Morphometric Analysis (morphometric + analysis)

Distribution by Scientific Domains
Distribution within Life Sciences

Kinds of Morphometric Analysis

  • geometric morphometric analysis
  • multivariate morphometric analysis
  • quantitative morphometric analysis


  • Selected Abstracts


    SYSTEMATICS OF THE HILDENBRANDIALES (RHODOPHYTA): GENE SEQUENCE AND MORPHOMETRIC ANALYSES OF GLOBAL COLLECTIONS,

    JOURNAL OF PHYCOLOGY, Issue 2 2003
    Alison R. Sherwood
    Fifty-seven collections of marine and freshwater Hildenbrandia from North America, South America, Europe, and Africa were compared with 21 type and historically important specimens using multivariate morphometrics. Additionally, phylogenetic analyses of 48 specimens of Hildenbrandia and two specimens of Apophlaea were carried out based on sequences of the rbcL chloroplast gene and the nuclear 18S rRNA gene. Morphometric analyses based on vegetative cell and filament dimensions distinguished two groups of freshwater Hildenbrandia specimens, the first corresponding to those collections from North America and the Philippines and the second to those from Europe and the Canary Islands. The first group had smaller mean cell and filament dimensions (cells 4.0 × 4.4 ,m, filaments 46.5 ,m) and corresponded to H. angolensis, whereas the second group had larger mean dimensions (cells 5.8 × 6.6 ,m, filaments 55.3 ,m) and represented H. rivularis. Marine specimens were morphometrically distinguishable into two groups based on tetrasporangial division pattern as well as other thallus characters. However, measurements and character determinations of some type specimens differed greatly from the original descriptions, and thus further work to determine the stability of these characters is required. Phylogenetic reconstruction based on the 18S rRNA gene and rbcL gene sequence data generally demonstrated separation of the marine and freshwater forms of Hildenbrandia, with some marine taxa forming monophyletic groups (e.g. H. lecannellieri and H. occidentalis) and others forming paraphyletic groups (e.g. H. rubra). The two specimens of Apophlaea formed a monophyletic group within the paraphyletic genus Hildenbrandia. [source]


    Morphometric Analysis on the Size, Shape and Areal Distribution of Glacial Cirques in the Maritime Alps (Western French-Italian Alps)

    GEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 3 2004
    Paolo Roberto Federici
    Abstract The morphometry of 432 glacial cirques in the Maritime Alps (Western French-Italian Alps), studied over several years of fieldwork, was analysed with the use of a geographical information system. Some of the parameters automatically evaluated from digital elevation models required an objective and relatively new definition. In particular, cirque length was measured along a line that, from the threshold midpoint, splits the cirque into two equivalent surfaces; cirque width was automatically drawn as the longest line inscribed in the cirque and perpendicular to the length line. Significant correlations were found among the different factors and parameters analysed. In particular, cirque shape analysis showed that cirques develop allometrically in the three dimensions, i.e. more in length and width than in altitudinal range. Nevertheless cirques of the Maritime Alps have a regular, almost circular shape (mean L/W value = 1.07). The correlations among length, width and area are all very high (r2= 0.8,0.9). In terms of size, cirques show a wide range in area from 0.06 to 5.2 km2 with a mean value of 0.4 km2. The largest cirques are found on SSW-facing slopes and at high elevations. Small cirques can be found at all altitudes but all those at high elevation are part of compound cirques at the main head valleys. Most cirques (37%) are characterized by a northern aspect; NE and SW are also frequent directions. [source]


    Sexual Dimorphism in America: Geometric Morphometric Analysis of the Craniofacial Region,

    JOURNAL OF FORENSIC SCIENCES, Issue 1 2008
    Erin H. Kimmerle Ph.D.
    Abstract:, One of the four pillars of the anthropological protocol is the estimation of sex. The protocol generally consists of linear metric analysis or visually assessing individual skeletal traits on the skull and pelvis based on an ordinal scale of 1,5, ranging from very masculine to very feminine. The morphologic traits are then some how averaged by the investigator to estimate sex. Some skulls may be misclassified because of apparent morphologic features that appear more or less robust due to size differences among individuals. The question of misclassification may be further exemplified in light of comparisons across populations that may differ not only in cranial robusticity but also in stature and general physique. The purpose of this study is to further examine the effect of size and sex on craniofacial shape among American populations to better understand the allometric foundation of skeletal traits currently used for sex estimation. Three-dimensional coordinates of 16 standard craniofacial landmarks were collected using a Microscribe-3DX digitizer. Data were collected for 118 American White and Black males and females from the W.M. Bass Donated Collection and the Forensic Data Bank. The MANCOVA procedure tested shape differences as a function of sex and size. Sex had a significant influence on shape for both American Whites (F = 2.90; d.f. = 19, 39; p > F = 0.0024) and Blacks (F = 2.81; d.f. = 19, 37; p > F = 0.0035), whereas size did not have a significant influence on shape in either Whites (F = 1.69; d.f. = 19, 39; p > F = 0.08) or Blacks (F = 1.09; d.f. = 19, 37; p > F = 0.40). Therefore, for each sex, individuals of various sizes were statistically the same shape. In other words, while significant differences were present between the size of males and females (males on average were larger), there was no size effect beyond that accounted for by sex differences in size. Moreover, the consistency between American groups is interesting as it suggests that population differences in sexual dimorphism may result more from human variation in size than allometric variation in craniofacial morphology. [source]


    Reconstruction and Morphometric Analysis of the Nasal Airway of the Dog (Canis familiaris) and Implications Regarding Olfactory Airflow

    THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 11 2007
    Brent A. Craven
    Abstract The canine nasal airway is an impressively complex anatomical structure, having many functional roles. The complicated branching and intricate scrollwork of the nasal conchae provide large surface area for heat, moisture, and odorant transfer. Of the previous anatomical studies of the canine nasal airway, none have included a detailed rendering of the maxilloturbinate and ethmoidal regions of the nose. Here, we present a high-resolution view of the nasal airway of a large dog, using magnetic resonance imaging scans. Representative airway sections are shown, and a three-dimensional surface model of the airway is reconstructed from the image data. The resulting anatomic structure and detailed morphometric data of the airway provide insight into the functional nature of canine olfaction. A complex airway network is revealed, wherein the branched maxilloturbinate and ethmoturbinate scrolls appear structurally distinct. This is quantitatively confirmed by considering the fractal dimension of each airway, which shows that the maxilloturbinate airways are more highly contorted than the ethmoidal airways. Furthermore, surface areas of the maxilloturbinate and ethmoidal airways are shown to be much different, despite having analogous physiological functions. Functionally, the dorsal meatus of the canine nasal airway is shown to be a bypass for odorant-bearing inspired air around the complicated maxilloturbinate during sniffing for olfaction. Finally, nondimensional analysis is used to show that the airflow within both the maxilloturbinate and ethmoturbinate regions must be laminar. This work has direct relevance to biomimetic sniffer design, chemical trace detector development, intranasal drug delivery, and inhalation toxicology. Anat Rec, 290:1325,1340, 2007. © 2007 Wiley-Liss, Inc. [source]


    Morphometric Analysis of the Canal System of Cortical Bone: An Experimental Study in the Rabbit Femur Carried Out with Standard Histology and Micro-CT

    ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2010
    U. E. Pazzaglia
    Summary The osteonal pattern of cortical bone is gradually built around the intracortical vessels by the progression of the cutting cones (secondary remodelling); therefore, the central canal size can be used as index of the remodelling activity. An experimental model in the rabbit femur was used to investigate, through central canal morphometry and frequency distribution analysis, the remodelling activity, comparing the middle of the diaphysis (mid-shaft) with the extremity (distal-shaft) and at the same level sectors and layers of the cortex in transversal sections. The study documented a higher density of canals in the mid-shaft than in the distal-shaft and a higher remodelling in the distal-shaft. There were no significant differences between dorsal, ventral, medial and lateral sectors at both mid-shaft and distal-shaft levels, while the number of canals was higher in the sub-periosteal layers than in the sub-endosteal. A lower threshold of 40 ,m2 was observed in the central canal area. Sealed osteons in the midshaft were 22.43% of the total number of osteons of the central canal area between 40 and 200 ,m2 and 0.44% of those of the distal-shaft. Micro-CT allowed a 3D reconstruction of the vascular canal system, which confirmed the branched network pattern rather than the trim architecture of the traditional representation. Some aspects like the lower threshold of the central canal size and the sealed osteons documented the plasticity of the system and its capacity for adaptation to changes in the haemodynamic conditions. [source]


    Phrenic Nerve Distribution in the Rabbit Diaphragm and Morphometric Analysis of Nerve Branches

    ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2006
    H. B. Turgut
    Summary The best method to evaluate the pathogenesis of diaphragmatic disorders is to demonstrate the distribution pattern of the phrenic nerve in the diaphragm. For this purpose the branching pattern and the microanatomic features of the phrenic nerve were observed in six rabbits. All diaphragms were stained by using Sihler's stain method. The phrenic nerve divided into three to four branches when entering the diaphragm. These branches were classified as sternal, anterolateral, posterolateral and crural. The crural branches were the thickest whereas the anterolateral branches were the thinnest. Knowledge about the distribution pattern of the phrenic nerve may be important in surgical approach to the diaphragm. [source]


    Corpus callosum and posterior fossa development in monozygotic females: a morphometric MRI study of Turner syndrome

    DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 5 2003
    Susannah L Fryer BA
    Previous neuroimaging research in Turner syndrome (TS) has indicated parietal lobe anomalies, while anomalies in other brain loci have been less well-substantiated. This study focused on potential cerebellar abnormalities and possible disruptions of interhemispheric (parietal) callosal connections in individuals with TS. Twenty-seven female children and adolescents with TS (mean age 13 years, SD 4 years 2 months) and 27 age-matched female control individuals (mean age 13 years 2 months, SD 4 years 1 month) underwent MRI. Age range of all participants was 7 to 20 years. Morphometric analyses of midline brain structures were conducted using standardized, reliable methods. When compared with control participants, females with TS showed reduced areas of the genu of the corpus callosum, the pons, and vermis lobules VI,VII, and an increased area of the fourth ventricle. No group difference in intracranial area measurements was observed. The reduced area of the genu in TS may reflect compromised connectivity between inferior parietal regions. Further, cerebellar vermis hypoplasia associated with TS agrees with literature that suggests the posterior fossa as a region prone to structural alterations in the face of early developmental insult. [source]


    Guidelines for assessment of bone microstructure in rodents using micro,computed tomography

    JOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2010
    Mary L Bouxsein
    Abstract Use of high-resolution micro,computed tomography (µCT) imaging to assess trabecular and cortical bone morphology has grown immensely. There are several commercially available µCT systems, each with different approaches to image acquisition, evaluation, and reporting of outcomes. This lack of consistency makes it difficult to interpret reported results and to compare findings across different studies. This article addresses this critical need for standardized terminology and consistent reporting of parameters related to image acquisition and analysis, and key outcome assessments, particularly with respect to ex vivo analysis of rodent specimens. Thus the guidelines herein provide recommendations regarding (1) standardized terminology and units, (2) information to be included in describing the methods for a given experiment, and (3) a minimal set of outcome variables that should be reported. Whereas the specific research objective will determine the experimental design, these guidelines are intended to ensure accurate and consistent reporting of µCT-derived bone morphometry and density measurements. In particular, the methods section for papers that present µCT-based outcomes must include details of the following scan aspects: (1) image acquisition, including the scanning medium, X-ray tube potential, and voxel size, as well as clear descriptions of the size and location of the volume of interest and the method used to delineate trabecular and cortical bone regions, and (2) image processing, including the algorithms used for image filtration and the approach used for image segmentation. Morphometric analyses should be based on 3D algorithms that do not rely on assumptions about the underlying structure whenever possible. When reporting µCT results, the minimal set of variables that should be used to describe trabecular bone morphometry includes bone volume fraction and trabecular number, thickness, and separation. The minimal set of variables that should be used to describe cortical bone morphometry includes total cross-sectional area, cortical bone area, cortical bone area fraction, and cortical thickness. Other variables also may be appropriate depending on the research question and technical quality of the scan. Standard nomenclature, outlined in this article, should be followed for reporting of results. © 2010 American Society for Bone and Mineral Research [source]


    Induction of oxidative stress by homocyst(e)ine impairs endothelial function,

    JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2001
    Vibhas S. Mujumdar
    Abstract Previous studies have demonstrated a relationship between hyperhomocysteinemia and endothelial dysfunction, reduced bioavailability of nitric oxide, elastinolysis and, vascular muscle cell proliferation. In vivo decreased nitric oxide production is associated with increased matrix metalloproteinase (MMP) activity and formation of nitrotyrosine. To test the hypothesis that homocysteine neutralizes vascular endothelial nitric oxide, activates metalloproteinase, causes elastinolysis and vascular hypertrophy, we isolated aortas from normotensive Wistar rats and cultured them in medium containing homocysteine, and calf serum for 14 days. Homocysteine-mediated impairment of endothelial-dependent vasodilatation was reversed by co-incubation of homocysteine with nicotinamide (an inhibitor of peroxinitrite and nitrotyrosine), suggesting a role of homocysteine in redox-mediating endothelial dysfunction and nitrotyrosine formation. The Western blot analysis, using anti-nitrotyrosine antibody, on aortic tissue homogeneates demonstrated decreased nitrotyrosine in hyperhomocysteinemic vessels treated with nicotinamide. Zymographic analysis revealed increased elastinolytic gelatinase A and B (MMP-2, -9) in homocysteine treated vessels and the treatment with nicotinamide decreases the homocysteine-induced MMP activation. Morphometric analyses revealed significant medial hypertrophic thickening (1.4,±,0.2-fold of control, P,=,0.03) and elastin disruption in homocysteine-treated vessels as compared to control. To determine whether homocysteine causes endothelial cell injury, cross-sections of aortas were analyzed for caspase activity by incubating with Ac-YVAD-AMC (substrate for apoptotic enzyme, caspase). The endothelium of homocysteine treated vessels, and endothelial cells treated with homocysteine, showed marked labeling for caspase. The length-tension relationship of homocysteine treated aortas was shifted to the left as compared to untreated aortas, indicating reduced vascular elastic compliance in homocysteine-treated vessels. Co-incubation of homocysteine and inhibitors of MMP, tissue inhibitor of metalloproteinase-4 (TIMP-4), and caspase, YVAD-CHO, improved vascular function. The results suggest that alteration in vascular elastin/collagen ratio and activation of MMP-2 are associated with decreased NO production in hyperhomocysteinemia. J. Cell. Biochem. 82:491,500, 2001. © 2001 Wiley-Liss, Inc. [source]


    SYSTEMATICS OF THE HILDENBRANDIALES (RHODOPHYTA): GENE SEQUENCE AND MORPHOMETRIC ANALYSES OF GLOBAL COLLECTIONS,

    JOURNAL OF PHYCOLOGY, Issue 2 2003
    Alison R. Sherwood
    Fifty-seven collections of marine and freshwater Hildenbrandia from North America, South America, Europe, and Africa were compared with 21 type and historically important specimens using multivariate morphometrics. Additionally, phylogenetic analyses of 48 specimens of Hildenbrandia and two specimens of Apophlaea were carried out based on sequences of the rbcL chloroplast gene and the nuclear 18S rRNA gene. Morphometric analyses based on vegetative cell and filament dimensions distinguished two groups of freshwater Hildenbrandia specimens, the first corresponding to those collections from North America and the Philippines and the second to those from Europe and the Canary Islands. The first group had smaller mean cell and filament dimensions (cells 4.0 × 4.4 ,m, filaments 46.5 ,m) and corresponded to H. angolensis, whereas the second group had larger mean dimensions (cells 5.8 × 6.6 ,m, filaments 55.3 ,m) and represented H. rivularis. Marine specimens were morphometrically distinguishable into two groups based on tetrasporangial division pattern as well as other thallus characters. However, measurements and character determinations of some type specimens differed greatly from the original descriptions, and thus further work to determine the stability of these characters is required. Phylogenetic reconstruction based on the 18S rRNA gene and rbcL gene sequence data generally demonstrated separation of the marine and freshwater forms of Hildenbrandia, with some marine taxa forming monophyletic groups (e.g. H. lecannellieri and H. occidentalis) and others forming paraphyletic groups (e.g. H. rubra). The two specimens of Apophlaea formed a monophyletic group within the paraphyletic genus Hildenbrandia. [source]


    Morphometric analysis of neuromuscular topography in the serratus anterior muscle

    MUSCLE AND NERVE, Issue 3 2006
    S. Potluri PhD
    Abstract Groups of neurons form ordered topographic maps on their targets, and defining the mechanisms that develop such maps, and reconnect them after disruption, has biological as well as clinical importance. The neuromuscular system is an accessible and well-studied model for defining the principles that guide map formation, both during its development and its reformation after motor nerve damage. We present evidence for the expression of this map at the level of nerve terminal morphology and muscle fiber type in the serratus anterior muscle. Morphometric analyses indicate, first, a rostrocaudal difference in nerve terminal size depending on the ventral root of origin of the axons. Second, motor endplates are larger on type IIB than type IIA muscle fibers. Third, whereas IIB muscle fibers are distributed rather evenly along the rostrocaudal axis of the muscle, the more rostral type IIB fibers are preferentially innervated by anteriorly derived (C6) motor neurons, and more caudal IIB fibers are preferentially innervated by posteriorly derived (C7) motor neurons. This inference is supported by analysis of the size of nerve terminals formed in each muscle sector by rostral and caudal roots, and by evidence that the larger terminals are on IIB fibers. These results demonstrate a subcellular expression of neuromuscular topography in the serratus anterior muscle (SA) muscle in the form of differences in nerve terminal size. These results provide deeper insights into the organization of a neuromuscular system. They also offer a rationale for a topographic map, that is, to allow spinal motor centers to activate selectively different compartments within a muscle. Muscle Nerve, 2006 [source]


    SYSTEMATICS OF THE CAMBRIAN TRILOBITE FAMILY NEPEIDAE, WITH REVISION OF AUSTRALIAN SPECIES

    PALAEONTOLOGY, Issue 3 2005
    JOHN R. PATERSON
    Abstract:, Taxonomy of the Cambrian trilobite family Nepeidae is revised. Morphometric analyses of the genera Nepea and Penarosa demonstrate that use of proportions of linear dimensions of the cranidium to differentiate species is invalid, and that infrageneric variation is continuous. The taxonomy and biostratigraphy of all Australian species of Nepeidae is revised. Species considered valid herein include: Nepea narinosa (type species), N. tonsillata, N. nans, Penarosa retifera (type species), P. elaticeps, P. rhinodelphis, P. netenta, Loxonepea loxophrys (type species) and Ferenepea hispida (type species). Folliceps is considered to be a junior subjective synonym of Nepea, Trinepea is regarded as a junior subjective synonym of Penarosa, and Ascionepea is considered to be a junior subjective synonym of Ferenepea. [source]


    Evidence of cell-nonautonomous changes in dendrite and dendritic spine morphology in the met-signaling,deficient mouse forebrain

    THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 21 2010
    Matthew C. Judson
    Abstract Human genetic findings and murine neuroanatomical expression mapping have intersected to implicate Met receptor tyrosine kinase signaling in the development of forebrain circuits controlling social and emotional behaviors that are atypical in autism-spectrum disorders (ASD). To clarify roles for Met signaling during forebrain circuit development in vivo, we generated mutant mice (Emx1Cre/Metfx/fx) with an Emx1-Cre-driven deletion of signaling-competent Met in dorsal pallially derived forebrain neurons. Morphometric analyses of Lucifer yellow-injected pyramidal neurons in postnatal day 40 anterior cingulate cortex (ACC) revealed no statistically significant changes in total dendritic length but a selective reduction in apical arbor length distal to the soma in Emx1Cre/Metfx/fx neurons relative to wild type, consistent with a decrease in the total tissue volume sampled by individual arbors in the cortex. The effects on dendritic structure appear to be circuit-selective, insofar as basal arbor length was increased in Emx1Cre/Metfx/fx layer 2/3 neurons. Spine number was not altered on the Emx1Cre/Metfx/fx pyramidal cell populations studied, but spine head volume was significantly increased (,20%). Cell-nonautonomous, circuit-level influences of Met signaling on dendritic development were confirmed by studies of medium spiny neurons (MSN), which do not express Met but receive Met-expressing corticostriatal afferents during development. Emx1Cre/Metfx/fx MSN exhibited robust increases in total arbor length (,20%). As in the neocortex, average spine head volume was also increased (,12%). These data demonstrate that a developmental loss of presynaptic Met receptor signaling can affect postsynaptic morphogenesis and suggest a mechanism whereby attenuated Met signaling could disrupt both local and long-range connectivity within circuits relevant to ASD. J. Comp. Neurol. 518:4463,4478, 2010. © 2010 Wiley-Liss, Inc. [source]


    Intraspecific genome size variation and morphological differentiation of Ranunculus parnassifolius (Ranunculaceae), an Alpine,Pyrenean,Cantabrian polyploid group

    BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2010
    EDUARDO CIRES
    The aim of this study was to assess genome size variation and multivariate morphometric analyses to ascertain cytotype distribution patterns and the morphological differentiation within the Ranunculus parnassifolius group in the Pyrenees and the Alps. Although divergences in nuclear DNA content among different species within a genus are widely acknowledged, intraspecific variation is still a somewhat controversial issue. Holoploid and monoploid genome sizes (C- and Cx-values) were determined using propidium iodide flow cytometry in 125 plants of R. parnassifolius s.l. distributed across four European countries. Three different DNA ploidy levels were revealed in the study area: diploid (2n , 2x, 57.14%), triploid (2n , 3x, 1.19%), and tetraploid (2n , 4x, 41.67%). The mean population 2C-values ranged from 8.15 pg in diploids to 14.80 pg in tetraploids, representing a ratio of 1 : 1.8. Marked intraspecific/interpopulation differences in nuclear DNA content were found. Diploid populations prevail in the Pyrenees, although tetraploid cytotypes were reported throughout the distribution area. In general, mixed-cytotype populations were not found. The Spearman correlation coefficient did not reveal significant correlations between genome size and altitude, longitude, or latitude. Morphometric analyses and cluster analyses based on genome size variation revealed the presence of three major groups, which exhibited a particular biogeographical pattern. A new cytotype, DNA triploid, was found for the first time. Tetraploid populations showed constant nuclear DNA levels, whereas diploid populations from the Pyrenees, in which introgressive hybridization is suggested as a presumable trigger for genome size variation, did not. Scenarios for the evolution of geographical parthenogenesis in R. parnassifolius s.l. are discussed. Finally, the different levels of effectiveness between plant and animal reference standards are analysed. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 251,271. [source]


    Are there two cryptic species of the lesser jerboa Jaculus jaculus (Rodentia: Dipodidae) in Tunisia?

    BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2010
    Evidence from molecular, cytogenetic data, morphometric
    Jerboas belonging to the genus Jaculus are widely distributed rodents inhabiting Palearctic desert and semi-desert areas. Previous studies on the lesser Egyptian jerboa Jaculus jaculus showed the existence of various morphological forms of controversial taxonomic status. They were sometimes related to two different species, J. jaculus and Jaculus deserti, although this has not been recognized in recent taxonomic updates. To clarify the systematic status of J. jaculus in Tunisia, we performed molecular (phylogenetic analyses of cytochrome b sequences), morphological (multivariate analyses of 13 skull measurements) and karyotypic (standard preparations from bone marrow cells) analyses on a number of specimens collected from ten localities. Our analyses revealed two monophyletic, well differentiated clades, with a mean genetic divergence value (K2P = 10.9 ± 0.01%), which is within the range of distances generally observed between rodent species. Morphometric analyses clearly separated populations of the two genetic clades from each other. However, karyotypes of individuals from both clades appeared similar. Individuals from both molecular clades/morphometric groups were found in sympatry in most of the localities sampled. These results, as obtained from a restricted area of the total distribution, suggest that there are two separate species within the currently accepted J. jaculus in Tunisia. Alternative hypotheses such as the occurrence of a strong, ancient phylogeographic structure, or the presence of pseudogenes, are also considered to account for the results obtained. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 673,686. [source]


    Caspr reveals an aggregation of nodes and flanking node free zones at the rat trigeminal sensory root and dorsal root entry zones

    GLIA, Issue 3 2005
    Michael A. Henry
    Abstract The sensory root entry zone demarcates the transition from the peripheral nervous system (PNS) to the central nervous system (CNS). In this study, we describe the organization of nodes of Ranvier at the trigeminal sensory and dorsal root entry zones of the rat. Caspr immunoreactivity (IR) was used to identify the paranodal region of nodes of Ranvier, while L-MAG-IR was used to identify CNS oligodendrocytes. Immunofluorescence confocal microscopy revealed a dense aggregation of nodes precisely at the PNS to CNS transition with prominent node-depleted zones on either side, while L-MAG-IR was confined to ensheathing fibers on the central side of nodes located in this dense band and identified these as transitional nodes. Morphometric analysis of the PNS and CNS sides of the trigeminal and the PNS side of the dorsal root entry zones confirmed the presence of virtually node-free domains flanking the transitional zone. Further, the reappearance of nodes on the far side of the node-free zones strongly correlated with nodal diameter, with small nodes reappearing first. These findings suggest that the PNS/CNS transition may represent the initial site of myelination of the primary afferent axon within this area. © 2004 Wiley-Liss, Inc. [source]


    Comparison Insight Bone Measurements by Histomorphometry and ,CT,

    JOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2005
    Daniel Chappard MD
    Abstract Morphometric analysis of 70 bone biopsies was done in parallel by ,CT and histomorphometry. ,CT provided higher results for trabecular thickness and separation because of the 3D shape of these anatomical objects. Introduction: Bone histomorphometry is used to explore the various metabolic bone diseases. The technique is done on microscopic 2D sections, and several methods have been proposed to extrapolate 2D measurements to the 3D dimension. X-ray ,CT is a recently developed imaging tool to appreciate 3D architecture. Recently the use of 2D histomorphometric measurements have been shown to provide discordant results compared with 3D values obtained directly. Material and Methods: Seventy human bone biopsies were removed from patients presenting with metabolic bone diseases. Complete bone biopsies were examined by ,CT. Bone volume (BV/TV), Tb.Th, and Tb.Sp were measured on the 3D models. Tb.Th and Tb.Sp were measured by a method based on the sphere algorithm. In addition, six images were resliced and transferred to an image analyzer: bone volume and trabecular characteristics were measured after thresholding of the images. Bone cores were embedded undecalcified; histological sections were prepared and measured by routine histomorphometric methods providing another set of values for bone volume and trabecular characteristics. Comparison between the different methods was done by using regression analysis, Bland-Altman, Passing-Bablock, and Mountain plots. Results: Correlations between all parameters were highly significant, but ,CT overestimated bone volume. The osteoid volume had no influence in this series. Overestimation may have been caused by a double threshold used in ,CT, giving trabecular boundaries less well defined than on histological sections. Correlations between Tb.Th and Tb.Sp values obtained by 3D or 2D measurements were lower, and 3D analysis always overestimated thickness by ,50%. These increases could be attributed to the 3D shape of the object because the number of nodes and the size of the marrow cavities were correlated with 3D values. Conclusion: In clinical practice, ,CT seems to be an interesting method providing reliable morphometric results in less time than conventional histomorphometry. The correlation coefficient is not sufficient to study the agreement between techniques in histomorphometry. The architectural descriptors are influenced by the algorithms used in 3D. [source]


    Contribution of Nitric Oxide Synthase to Improved Early Graft Patency in Human Saphenous Vein Graft Harvested by a Novel ,No-Touch' Technique

    JOURNAL OF CARDIAC SURGERY, Issue 6 2002
    JCS Tsui
    Aim: Saphenous vein (SV) is the most commonly used conduit in bypass procedures but has a one-year occlusion rate of 15-30%. A new ,no-touch' technique where the SV is harvested with a cushion of surrounding tissue with no distension has led to improved early patency rates of 5% at 18-months. Nitric oxide (NO), synthesised by nitric oxide synthase (NOS) has properties beneficial to graft patency. Our aim was to study the distribution of NOS in SV harvested by this technique and the effect of distension and removal of perivascular tissue on NOS content of SV. Methods: Following ethical committee approval and patients' informed consent, SVs were harvested from ten patients undergoing coronary artery bypass grafting. A segment of vein was harvested by the conventional technique (surrounding tissue stripped and vein distended with saline); another part was stripped but not distended (,control') and the remaining parts harvested by the ,no-touch' technique. Samples of each segment were taken and transverse sections prepared for NOS identification using 3[H]L-NG nitroarginine (NO Arg) autoradiography and NADPH-diaphorase histochemistry. NOS isoforms were studied using standard immunohistochemistry. Endothelial cells and nerves were also identified using immunohistochemistry with CD31 and NF200 respecitvely, to confirm sources of NOS. Morphometric analysis of NADPH-diaphorase staining was carried out to study tissue NOS content. Results: NO Arg binding representing NOS was preserved on the lumen of ,no-touch' vessels whilst that on conventional and control vessels was reduced. NOS was also localised to the medial smooth muscle cells of all vein segments and to the intact adventitia of ,no-touch' segments. This was confirmed by NADPH-diaphorase staining, which revealed a mean reduction of NOS by 19.5% (p < 0.05, ANOVA) in control segments due to stripping of surrounding tissue alone and a reduction of 35.5% (p < 0.01, AVNOVA) in conventional segments due to stripping and distension, compared to ,no-touch' segments. Adventitial NOS sources in ,no-touch' vessels corresponded to vasa vasorum and paravascular nerves. All three NOS isoforms contributed to the preserved NOS in ,no-touch' vessels. Conclusions: Apart from preserved lumenal NOS, NOS sources are also located in the media and adventitia of SV grafts. These are reduced by both adventitial damage and vein distension during conventional vein harvesting. The ,no-touch' technique avoids these procedures, preserving NOS sources. This may result in improved NO availability in SV harvested by this technique, contributing to the improved patency rates reported. [source]


    Evaluation of processed bovine cancellous bone matrix seeded with syngenic osteoblasts in a critical size calvarial defect rat model

    JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 3 2006
    U. Kneser
    Abstract Introduction: Biologic bone substitutes may offer alternatives to bone grafting procedures. The aim of this study was to evaluate a preformed bone substitute based on processed bovine cancellous bone (PBCB) with or without osteogenic cells in a critical size calvarial defect rat model. Methods: Discs of PBCB (Tutobone®) were seeded with second passage fibrin gel-immobilized syngenic osteoblasts (group A, n = 40). Cell-free matrices (group B, n = 28) and untreated defects (group C; n=28) served as controls. Specimens were explanted between day 0 and 4 months after implantation and were subjected to histological and morphometric evaluation. Results: At 1 month, bone formation was limited to small peripheral areas. At 2 and 4 months, significant bone formation, matrix resorption as well as integration of the implants was evident in groups A and B. In group C no significant regeneration of the defects was observed. Morphometric analysis did not disclose differences in bone formation in matrices from groups A and B. Carboxyfluorescine-Diacetate-Succinimidylester (CFDA) labeling demonstrated low survival rates of transplanted cells. Discussion: Osteoblasts seeded into PBCB matrix display a differentiated phenotype following a 14 days cell culture period. Lack of initial vascularization may explain the absence of added osteogenicity in constructs from group A in comparison to group B. PBCB is well integrated and represents even without osteogenic cells a promising biomaterial for reconstruction of critical size calvarial bone defects. [source]


    Chondrocranial development in larval Rana sylvatica (Anura: Ranidae): Morphometric analysis of cranial allometry and ontogenetic shape change

    JOURNAL OF MORPHOLOGY, Issue 2 2002
    Peter M. Larson
    Abstract This study provides baseline quantitative data on the morphological development of the chondrocranium in a larval anuran. Both linear and geometric morphometric methods are used to quantitatively analyze size-related shape change in a complete developmental series of larvae of the wood frog, Rana sylvatica. The null hypothesis of isometry was rejected in all geometric morphometric and most linear morphometric analyses. Reduced major axis regressions of 11 linear chondrocranial measurements on size indicate a mixture of allometric and isometric scaling. Measurements in the otic and oral regions tend to scale with negative allometry and those associated with the palatoquadrate and muscular process scale with isometry or positive allometry. Geometric morphometric analyses, based on a set of 11 chondrocranial landmarks, include linear regression of relative warp scores and multivariate regression of partial warp scores and uniform components on log centroid size. Body size explains about one-quarter to one-third of the total shape variation found in the sample. Areas of regional shape transformation (e.g., palatoquadrate, otic region, trabecular horns) are identified by thin-plate spline deformation grids and are concordant with linear morphometric results. Thus, the anuran chondrocranium is not a static structure during premetamorphic stages and allometric patterns generally follow scaling predictions for tetrapod cranial development. Potential implications regarding larval functional morphology, cranial development, and chondrocranial evolution in anurans are discussed. J. Morphol. 252:131,144, 2002. © 2002 Wiley-Liss, Inc. [source]


    Morphometric analysis of CD34-positive vessels in salivary gland adenoid cystic and mucoepidermoid carcinomas

    JOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 9 2009
    H. Luukkaa
    Background:, Carcinomas of the salivary glands are uncommon and morphologically a diverse group of malignancies. To evaluate the prognostic value of CD34 immunostaining of the vessels in adenoid cystic carcinoma (AdCC) and mucoepidermoid carcinoma (MEC), an automated image analysis method was used. Method:, In a nationwide study, covering salivary gland cancer (SGC) patients in Finland 1991,1996, 37 AdCC and 18 MEC patients (M 25, F 30, age 25,90, mean 63) were included. In addition to clinical characteristics the size, shape, staining intensity and vessel density in CD34 immunostained histologic samples were measured. Results:, Altogether 4433 vessels were measured from AdCC and 2615 from MEC tumor. Of the total tumor vessels measured, 2651 were from patients who deceased with disease (Group I) and 4397 were from specimens derived from those who did not die of disease (Group II) during the 10-year follow-up. The staining intensity was significantly higher in MEC than in AdCC tumor (P = 0.0005). In MEC, the Group I patients had a higher staining intensity among high-grade patients compared with patients with low grade disease, whereas the tumors in Group II had a lower staining intensity among the high-grade compared with the low grade tumors (P = 0.018). A higher vessel density was found in patients with MEC in group II compared with group I (P = 0.017). Conclusions:, The staining intensity of CD34 positive vessels in MEC was higher than in AdCC. In MEC, higher staining intensity of vessels in high-grade tumors and lower vessel density in all MEC patients, predicted poor survival. [source]


    Morphometric analysis of canine skeletal muscles following experimental callus distraction according to the ilizarov method

    JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2000
    Bernd Fink
    Muscle fiber diameter and fiber-type distribution were analyzed during callus distraction. The right tibia in 24 beagles was lengthened 2.5 cm by callus distraction after osteotomy and application of a ring fixator. Distraction was started at the fifth postoperative day, at a rate of two times for 0.5 mm per day. Twelve dogs that underwent limb-lengthening and three dogs in the control group that did not undergo limb-lengthening were killed at the end of the 25-day distraction phase (group A). The remaining dogs (12 that underwent limb-lengthening and three that did not) were killed after an additional consolidation period of 25 days (group B). The tibialis anterior, extensor digitorum longus, peroneus longus, and gastrocnemius muscles were removed from the right limb (which had undergone distraction) and the left control side of each animal. Crosscut cryostat sections were stained by adenosine triphosphatase at pH 4.3 and 9.4 to determine the size and distribution of types I and II fibers. Morphometric analysis of the muscle fibers was performed by a computer-assisted two-point technique. On the lengthened side, the muscles revealed marked atrophy affecting predominantly type-II fiber in the dogs in group A and affecting both fiber types in dogs in group B. Fiber density increased in both groups. In addition, fiber-type grouping indicative of reinnervation was obvious in group B. Fiber-type distribution in the dogs in group B showed a shift toward type I in the tibialis anterior (p = 0.043) and extensor digitorum longus (p = 0.034) muscles and a shift toward type II in the gastrocnemius (p = 0.038). The data show that tension-stress during tibial lengthening leads to atrophy of type-II fiber, reflecting disuse of muscle fiber in the distraction period as well as neurogenic atrophy followed by the reinnervation processes. Furthermore, the data are consistent with the occurrence of histoneogenesis during limb-lengthening resulting in an increase in fiber density. [source]


    A quantitative comparison of the ontogeny of two closely-related Upper Devonian phacopid trilobites

    LETHAIA, Issue 2 2005
    CATHERINE CRÔNIER
    The best insight into the development of Devonian phacopids has been obtained from Trimerocephalus lelievrei Crônier & Feist, 1997, a Famennian phacopine from Morocco, where changes in size and shape have been quantified. In this study, a morphometric approach has been used: (1) to retrodeform and then establish patterns of morphological variation in a well preserved but tectonically deformed assemblage belonging to another phacopine species Weyerites ensae (Richter & Richter, 1926), a Famennian phacopine from Thuringia, and (2) to establish patterns of developmental and evolutionary changes within two closely related species: Weyerites ensae and Trimerocephalus lelievrei. The method of retrodeformation using a set of discrete points presumed to be homologous on all studied individuals, has demonstrated that the next analyses are possible on the retrodeformed material as compared to the undeformed material. Morphometric analysis based on outline analysis has permitted demonstration of progressive shape change in agreement with ontogenetic ordination and a comparison of changes in size and shape in Weyerites ensae. The main changes in shape appear to occur in the meraspid period, whereas increase in size takes place mainly in the holaspid period. This pattern, already reported for Trimerocephalus lelievrei, can be generalized for phacopine trilobites from the Late Devonian. Moreover, the comparison of the two ontogenetic trajectories has shown that most of the differences are related to ,structural' changes, probably linked to a relative pre- post-displacement. The results suggest that ecological adaptation may be studied by examining the changes in development that occur within species through time and space. [source]


    Nerve regeneration through an epineurial sheath: Its functional aspect compared with nerve and vein grafts

    MICROSURGERY, Issue 5 2001
    Ercan Karacao, lu M.D.
    Although nerve graft is still the only reliable choice in repair of defects in peripheral nerve structure, it has the disadvantage of donor nerve morbidity and of sometimes being unavailable. It has long been researched in alternate nerve grafts with other materials. Studies have shown that nerves could regenerate across short nerve gaps through various conduits, such as veins, pseudosheaths, and bioabsorbable tubes. Despite encouraging studies, their functional results remain unclear. The present study used 40 rats, in which nerve grafts, vein grafts, and epineurial tubes were placed into 1-cm gaps in sciatic nerves created by resection. In one group, sciatic nerves were denuded of the surrounding epineurium, to assess the possible morbidity caused by epineurial sheath technique. At 2, 4, 8, 12, 20, and 28 weeks, functional assessment of nerve regeneration was performed using walking track analysis. The number of myelinated fibers and fiber diameters was measured and electron microscopic evaluation performed. Functionally, the index values were very close to each other in nerve graft and epineurial sheath groups. Morphometric analysis showed significance between the groups. The result of denuded sciatic nerve group was the same as the base track values. It was concluded that the ready availability of epineurial sheath as a conduit to span short nerve gaps could eliminate the morbidity associated with nerve graft harvest and capitalize on the potential benefits of neurotrophism in directing nerve regeneration. © 2001 Wiley-Liss, Inc. Microsurgery 21:196,201 2001 [source]


    Processed porcine collagen tubulization versus conventional suturing in peripheral nerve reconstruction: An experimental study in rabbits

    MICROSURGERY, Issue 3 2001
    Guda C.M. Heijke M.D.
    In peripheral nerve reconstruction, various procedures are used. One of the procedures that received the most interest in the past decade is the tubulization technique for small nerve gaps. A disadvantage in the use of non-biodegradable tubes is that the material often has to be removed owing to its mechanical properties. Some investigators, in exploring the use of collagen tubes, being a natural biodegradable material, found either allogenicity or xenogenicity and immune responses that may inhibit nerve regeneration. Processed porcine collagen (PPC) is a new inert and biodegradable material that has a favorable effect on wound healing, as demonstrated by experiments on other tissues. The aim of our study was to compare the healing of nerve sutures with PPC tubes with conventional end-to-end sutures. In our experiments, we reconstructed the saphenous nerves of 27 rabbits. In series 1 (n = 12) and 2 (n = 12), PPC tubes were slid over an end-to-end nerve suture without or with a 10-mm nerve gap, respectively. In series 3 (n = 12), conventional suturing was performed in the collateral saphenous nerves of the animals of series 1. Epineurial suturing was performed. Three other non-operated saphenous nerves served as controls. The healing was studied after 3, 6, and 12 months in sections stained by monoclonal antibodies and by conventional histologic staining. Morphometric analysis of the regenerating axons was done by using confocal scanning laser microscopy (CLSM). Data analysis was carried out using a software program especially developed for this purpose. All results were evaluated statistically. Our results showed that during the healing period in the distal nerve stump, the number of axons of the PPC procedure with a 10-mm gap was significantly higher than that in the procedure without a gap. At 12 months, the mean number of axons of all procedures was significantly lower than in the non-operated nerve, and the mean axon diameter in all distal stumps did not differ significantly from that of the non-operated nerve. In the distal nerve stump, the ratio of total axon area to total fascicle area in the PPC procedure with a gap was significantly higher than that in the conventional suturing procedure. After 12 months, there was no significant difference between the percentages of axon outgrowth of the PPC procedure without a gap, the conventional suturing procedure, and the non-operated nerve (100%). The percentage of axon outgrowth in PPC with a gap was significantly higher than in the other procedures. © 2001 Wiley-Liss, Inc. Microsurgery 21:84,95 2001 [source]


    Host-driven divergence in the parasitic plant Orobanche minor Sm. (Orobanchaceae)

    MOLECULAR ECOLOGY, Issue 19 2008
    C. J. THOROGOOD
    Abstract Many parasitic angiosperms have a broad host range and are therefore considered to be host generalists. Orobanche minor is a nonphotosynthetic root parasite that attacks a range of hosts from taxonomically disparate families. In the present study, we show that O. minor sensu lato may comprise distinct, genetically divergent races isolated by the different ecologies of their hosts. Using a three-pronged approach, we tested the hypothesis that intraspecific taxa O. minor var. minor and O. minor ssp. maritima parasitizing either clover (Trifolium pratense) or sea carrot (Daucus carota ssp. gummifer), respectively, are in allopatric isolation. Morphometric analysis revealed evidence of divergence but this was insufficient to define discrete, host-specific taxa. Intersimple sequence repeat (ISSR) marker-based data provided stronger evidence of divergence, suggesting that populations were isolated from gene flow. Phylogenetic analysis, using sequence-characterized amplified region (SCAR) markers derived from ISSR loci, provided strong evidence for divergence by clearly differentiating sea carrot-specific clades and mixed-host clades. Low levels of intrapopulation SCAR marker sequence variation and floral morphology suggest that populations on different hosts are probably selfing and inbreeding. Morphologically cryptic Orobanche taxa may therefore be isolated from gene flow by host ecology. Together, these data suggest that host specificity may be an important driver of allopatric speciation in parasitic plants. [source]


    Increased recombination frequency showing evidence of loss of interference is associated with abnormal testicular histopathology

    MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 4 2003
    Susannah Varmuza
    Abstract Nondisjunction leading to aneuploid gametes has been linked genetically to both increases and decreases in recombination frequency on the aneuploid chromosome. In the present study, we present physical evidence of increased frequency of recombination nodules as measured by Mut-S-like homologue-1 (MLH1) foci on pachytene chromosomes from sterile male mice homozygous for a mutation in the protein phosphatase 1c, (PP1c,) gene. The pattern of elevated recombination frequency in PP1c, mutant spermatocytes is consistent with a loss of interference. Previous studies demonstrated: (1) spermiogenesis is impaired starting at step 8 with a severe reduction in elongating and condensed spermatids; (2) spermatids and sperm exhibit elevated rates of DNA fragmentation; and (3) haploid gametes exhibit elevated levels of aneuploidy. Morphometric analysis of developing testes revealed that the first wave of meiosis proceeds at a normal rate in mutant testes, a surprising result given that the PP1 inhibitor okadaic acid has been shown to accelerate progression of spermatocytes from pachytene to the first meiotic division (MI). Evidence of abnormal testicular histopathology is apparent at 3 weeks, before the appearance of haploid gametes, eliminating the possibility that the mutant phenotype is caused by the presence of abnormal spermatids, but coincident with the appearance of the first set of mid to late pachytene spermatocytes. These observations lead us to conclude that the PP1c, mutation causes a complex phenotype, including subtle adverse effects on meiosis, possibly mediated by defective signaling between germ cells and Sertoli cells. Mol. Reprod. Dev. 64: 499,506, 2003. © 2003 Wiley-Liss, Inc. [source]


    Morphometric analysis of neuromuscular topography in the serratus anterior muscle

    MUSCLE AND NERVE, Issue 3 2006
    S. Potluri PhD
    Abstract Groups of neurons form ordered topographic maps on their targets, and defining the mechanisms that develop such maps, and reconnect them after disruption, has biological as well as clinical importance. The neuromuscular system is an accessible and well-studied model for defining the principles that guide map formation, both during its development and its reformation after motor nerve damage. We present evidence for the expression of this map at the level of nerve terminal morphology and muscle fiber type in the serratus anterior muscle. Morphometric analyses indicate, first, a rostrocaudal difference in nerve terminal size depending on the ventral root of origin of the axons. Second, motor endplates are larger on type IIB than type IIA muscle fibers. Third, whereas IIB muscle fibers are distributed rather evenly along the rostrocaudal axis of the muscle, the more rostral type IIB fibers are preferentially innervated by anteriorly derived (C6) motor neurons, and more caudal IIB fibers are preferentially innervated by posteriorly derived (C7) motor neurons. This inference is supported by analysis of the size of nerve terminals formed in each muscle sector by rostral and caudal roots, and by evidence that the larger terminals are on IIB fibers. These results demonstrate a subcellular expression of neuromuscular topography in the serratus anterior muscle (SA) muscle in the form of differences in nerve terminal size. These results provide deeper insights into the organization of a neuromuscular system. They also offer a rationale for a topographic map, that is, to allow spinal motor centers to activate selectively different compartments within a muscle. Muscle Nerve, 2006 [source]


    Partial depletion of macrophages by ED7 reduces renal injury in Adriamycin nephropathy

    NEPHROLOGY, Issue 5 2005
    YIPING WANG
    SUMMARY: Background: Because macrophages are considered to be possible effectors of disease in Adriamycin (ADR) nephrosis, we hypothesized that depletion of macrophages might protect against the initiation of renal injury. In the present study, a monoclonal antibody (ED7) directed against CD11b/CD18 integrin, which is expressed by macrophages, was used to investigate the pathogenetic effects of macrophages in ADR nephropathy. Methods: Male Wistar rats were treated with ED7 antibody, starting 1 day prior to ADR (7.5 mg/kg) treatment, or 7 days post-ADR when overt proteinuria was established. Results: Circulating ED7-positive cells were reduced by approximately 30% in rats with ADR nephrosis by the ED7 antibody, while the number of macrophages in the renal cortex of ADR rats was reduced by nearly 50% with the ED7 treatment, whether administered before or after ADR. Creatinine clearance was significantly ameliorated by ED7 when commenced pre-ADR (P < 0.05), but not when commenced post-ADR (P = NS) in comparison to untreated ADR rats. However, proteinuria was not alleviated by either ED7 treatment. Morphometric analysis showed less glomerular sclerosis when ED7 was commenced pre-ADR compared with ADR alone (P < 0.01), but not when commenced post-ADR (P = NS). Tubular atrophy was reduced by ED7 when it was commenced pre-ADR (tubular cell height and tubular diameter: P < 0.01 and P < 0.001, respectively), as was interstitial expansion (P < 0.01) compared with ADR alone. Cortical macrophage infiltration was reduced by 50% compared with ADR alone by the ED7 commenced before or after ADR. The number of cortical CD4+ T cells fell with ED7 starting pre-ADR, but not with the ED7 treatment commencing after ADR. Conclusion: Partial macrophage depletion starting before but not after ADR protected both renal function and structure in this model of chronic proteinuric renal disease. [source]


    External urethral sphincter activity in diabetic rats

    NEUROUROLOGY AND URODYNAMICS, Issue 5 2008
    Guiming Liu
    Abstract Aim To examine the temporal effects of diabetes on the bladder and the external urethral sphincter (EUS) activity in rats. Methods Female Sprague-Dawley rats (n,=,24) were divided into two groups: streptozotocin-induced diabetic rats and age-matched controls. Cystometrograms (CMGs) were taken under urethane anesthesia and electromyograms (EMG) of the EUS were evaluated in all rats at 6 and 20 weeks after diabetes induction. After EMG assessment, the tissues of the urethra were harvested for morphological examination. Results Diabetes caused reduction of body weight, but an increase in bladder weight. CMG measurements showed diabetes increased threshold volume, contraction duration, high-frequency oscillations (HFO), and residual volume. Peak contraction amplitude increased in 6-week but not 20-week diabetic rats. EUS-EMG measurements showed increased frequency of EUS-EMG bursting discharge during voiding in 6-week diabetic rats (8.1,±,0.2 vs. 6.9,±,0.6/sec) but not in 20-week (5.8,±,0.3 vs. 6.0,±,0.2/sec) diabetic rats compared with controls. EUS-EMG bursting periods were also increased in both 6-week and 20-week diabetic rats compared with controls. EUS-EMG silent periods were reduced in 6-week diabetic rats, but were not changed in 20-week diabetic rats compared with controls. Active periods did not change in 20-week diabetic rats, but increased in 6-week diabetic rats compared with controls. Morphometric analysis showed atrophy of the EUS after 20 week but not 6 weeks of DM induction. Conclusions Our data indicates diabetes causes functional and anatomical abnormalities of the EUS. These abnormalities may contribute to the time-dependent bladder dysfunction in diabetic rats. Neurourol. Urodynam. 27:429,434, 2008. © 2008 Wiley-Liss, Inc. [source]