EVOLUTION, Issue 4 2002
Mikko Heino
Abstract We present a new probabilistic concept of reaction norms for age and size at maturation that is applicable when observations are carried out at discrete time intervals. This approach can also be used to estimate reaction norms for age and size at metamorphosis or at other ontogenetic transitions. Such estimations are critical for understanding phenotypic plasticity and life-history changes in variable environments, assessing genetic changes in the presence of phenotypic plasticity, and calibrating size- and age-structured population models. We show that previous approaches to this problem, based on regressing size against age at maturation, give results that are systematically biased when compared to the probabilistic reaction norms. The bias can be substantial and is likely to lead to qualitatively incorrect conclusions; it is caused by failing to account for the probabilistic nature of the maturation process. We explain why, instead, robust estimations of maturation reaction norms should be based on logistic regression or on other statistical models that treat the probability of maturing as a dependent variable. We demonstrate the utility of our approach with two examples. First, the analysis of data generated for a known reaction norm highlights some crucial limitations of previous approaches. Second, application to the northeast arctic cod (Gadus morhua) illustrates how our approach can be used to shed new light on existing real-world data. [source]

PRESERVATION OF "UMBU" (SPONDIAS TUBEROSA ARRUDA CÂMARA) PULP IN THE GREEN STAGE OF MATURATION BY COMBINED METHODS

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 3 2007
ELIDA CONCEIÇÃO JORGE
ABSTRACT "Umbu" (Spondias tuberosa Arruda Câmara) is a typical fruit from northeastern Brazil of considerable economic importance to this region, because several products are derived from it and commercialized, especially the pulp, which can be used as a raw material for preserves and juices. The objective of this research was to study the preservation of umbu in the green stage of maturation by combined methods, including heat treatment and the addition of preservatives and sucrose. The pulps were blanched, pasteurized and mixed with the preservatives and sucrose according to a complete factorial design with three variables (ratio pulp/sucrose, potassium sorbate and sodium metabisulfite), two levels and two repetitions. The products were filled into high-density polyethylene packages and exposed to a temperature of 40C for 120 days. Physicochemical, color and chemical (SO2) analyses showed that the concentrations of sodium metabisulfite and potassium sorbate used did not significantly alter product quality. The addition of sucrose significantly decreased the water activity and led to intense browning. The microbiological evaluations showed good product stability for 120 days. The overall results indicated that the heat treatment applied was effective if high levels of hygiene were maintained during the preparatory stages and the packaging materials were well sanitized. The combined preservation methods appear to be an economic way to preserve these high-acid pulps. [source]

THE APPLICATION OF ELECTRON SPIN RESONANCE AS A GUIDE TO THE MATURATION AND TYPING OF ORGANIC MATTER IN THE NORTH SEA

JOURNAL OF PETROLEUM GEOLOGY, Issue 1 2003
R. A. McTavish
In early electron spin resonance (ESR) analysis of North Sea wells, maturation of organic matter (OM) was expressed in terms of maximum palaeotemperature (MPT) based on North American calibrations that did not consider the influences of kerogen composition or overpressure. In the North Sea, the MPTs were anomalous in overpressured sequences and relative to other indices of OM maturation such as vitrinite reflectance, so the ESR method was abandoned there in geochemical studies. However, early empirical study of North Sea ESR data indicated that, in relation to functions that linked temperature and pore pressure, some ESR parameters were predictable without reference to MPTs. In order to re-evaluate ESR parameters as indices of OM maturation, the physical factors (temperature and pressure) which affect OM maturation are related in the present paper to the ESR parameters "g" (spectral position) and Ng (spin density) at six well locations in the northern North Sea. A third ESR parameter, W (line width), is not an effective guide to maturation levels due to its complex relationship to the physical factors and kerogen types. However, cross-plots of W versus "g" and Ng appear to be as effective as pyrolysis for kerogen typing. Levels of maturation investigated in the North Sea wells range through the equivalent vitrinite reflectance values of about 0.50,1.50%. The values of "g" and Ng have been differentiated for kerogen type, but undifferentiated values of "g" have also been studied. Regression analysis has shown that there are linear relationships between the ESR parameters "g" and Ng, and the physical factors present-day temperature (To), "effective" temperature (Te), and differential pressure (Pd). Correlation coefficients for both "g" (undifferentiated and differentiated) and Ng (differentiated) relative to the physical factors are high; the highest values are for "g" and Ng relative to Te and Pd (r =,0.950 for "g" differentiated or undifferentiated, r = 0.944,0.976 for Ng differentiated, respectively). However, correlation coefficients were lower for "g" and Ng relative to To. More frequent high correlation coefficients and larger sample populations suggest that "g" (undifferentiated) is a more reliable index of OM maturation than Ng(differentiated). However, the estimation of levels of OM maturation is improved if both indices are used together. The ESR method appears to be effective both for estimating levels of OM maturation and for kerogen typing. It has a number of potential advantages over other geochemical methods: firstly, it is more sensitive for estimating OM maturation than most other methods; secondly, it can be used to analyze organic matter which is as old as Proterozoic; thirdly, it does not destroy the samples analyzed. [source]

Maturation of Corporate Governance Research, 1993,2007: An Assessment

CORPORATE GOVERNANCE, Issue 3 2009
Boris Durisin
ABSTRACT Manuscript Type: Review Research Question/Issue: This study seeks to investigate whether governance research in fact is a discipline or whether it is rather the subject of multi-disciplinary research. We map the intellectual structure of corporate governance research and its evolution from 1993,2007. Research Findings/Results: Based on the analysis of more than 1,000 publications and 48,000 citations in Corporate Goverance: An International Review (CGIR) and other academic journals, our study identifies the most influential works, the dominant subfields, and their evolution. Our study assesses the maturation of corporate governance research as a discipline; it finds increasing sophistication, depth and rigor, and consistency in its intellectual structure. Theoretical Implications: There is a large body of accumulated corporate governance research in the US, yet there is an empirical gap on cross-national studies in the literature. Furthermore, hardly any of the top cited works undertake their study in a cross-national setting. Thus, corporate governance research and CGIR in its quest to contribute to a global theory of corporate governance might benefit if articles have a cross-national methodological approach and empirical grounding in their research design and if articles explicitly aim at stating the theoretical underpinnings they draw on. Practical Implications: Globalists find in CGIR an outlet addressing economics and finance (e.g., whether and how compensation or dismissal of CEOs is related to board characteristics), management (e.g., whether and how best practice codes adoption is related to board characteristics and performance), and accounting (e.g., whether and how earnings manipulations is related to board characteristics) issues globally. [source]

Development of the corticospinal system and hand motor function: central conduction times and motor performance tests

DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 4 2000
U M Fietzek
Maturation of the corticospinal (CS) tract and hand motor function provide paradigms for central nervous system development. In this study, involving 112 participants (aged from 0.2 to 30 years), we evaluated central motor conduction times (CMCT) obtained with transcranial magnetic stimulation (TMS) during preinnervation conditions of facilitation and relaxation. Auditory reaction time, velocity of a ballistic movement of the arm, finger tapping, diadochokinesis, and fine motor visuomanual tracking were also examined. The maturation profiles for every parameter were calculated. CMCTs for the different preinnervation conditions reached adult values at different times and this could be explained by maturation of excitability at the cortical and spinal level. A stable phase for CMCTs and reaction time was reached during childhood. Parameters which measured motor speed and skill indicated that the development of these continued into adulthood. The maturation of the fast CS tract seems to be completed before the acquisition of the related motor performance has been accomplished. In conclusion, we could demonstrate that data from several neurophysiological methods can be combined and used to study the maturation of the function of the nervous system. This approach could allow appraisal of pathological conditions that show parallels with omissions or lack of developmental progress. [source]

Influences of postconceptional age and postnatal experience on the development of auditory recognition memory in the newborn infant

DEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2002
Raye-Ann deRegnier
Abstract We evaluated the effects of postconceptional age and postnatal experience on the development of neonatal auditory recognition memory. Three groups were tested: a premature newborn group (tested at 35,38 weeks postconceptional age, ,1 week old), a full-term newborn group (tested at 39,42 weeks postconceptional age, ,1 week old), and a full-term experienced group (tested at 39,42 weeks postconceptional age, >1 week old; range 8,30 days). Event-related potentials were collected while infants listened to the maternal voice alternating with a stranger's voice. Postconceptional age was correlated with the development of recognition memory for the maternal voice while there were qualitative effects of postnatal experience on latency measurements. Maturity of auditory cortical responses was not correlated with recognition memory abilities. We conclude that maturation of the recognition memory pathways is primarily a function of postconceptional age with qualitative effects of postnatal experience. Maturation of the auditory recognition memory pathway is not contingent upon maturation of the "P2" peak thought to arise from primary auditory cortex. © 2002 Wiley Periodicals, Inc. Dev Psychobiol 41: 216,225, 2002. Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/dev.10070 [source]

Maturation of action monitoring from adolescence to adulthood: an ERP study

DEVELOPMENTAL SCIENCE, Issue 6 2005
Alexandra M. Hogan
This study investigated the development of the frontal lobe action-monitoring system from late childhood and adolescence to early adulthood using ERP markers of error processing. Error negativity (ERN) and correct response negativity (CRN) potentials were recorded while adolescents and adults (aged 12,22 years, n = 23) performed two forced-choice visual reaction time tasks of differing complexity. Significant age differences were seen for behavioural and ERP responses to complex (infrequent, incompatible) trials: adolescents elicited an error negativity of reduced magnitude compared with adults. Furthermore, in contrast to adults, adolescents showed a non-significant differentiation between response-locked ERP components elicited by correct (CRN) and error responses (ERN). Behaviourally, adolescents corrected fewer errors in incompatible trials, and with increasing age there was greater post-error slowing. In conclusion, the neural systems underlying action-monitoring continue to mature throughout the second decade of life, and are associated with increased efficiency for fast error detection and correction during complex tasks. [source]

Maturation of fetal responses to music

DEVELOPMENTAL SCIENCE, Issue 5 2004
B.S. Kisilevsky
Maturation of fetal response to music was characterized over the last trimester of pregnancy using a 5-minute piano recording of Brahms' Lullaby, played at an average of 95, 100, 105 or 110 dB (A). Within 30 seconds of the onset of the music, the youngest fetuses (28,32 weeks GA) showed a heart rate increase limited to the two highest dB levels; over gestation, the threshold level decreased and a response shift from acceleration to deceleration was observed for the lower dB levels, indicating attention to the stimulus. Over 5 minutes of music, fetuses older than 33 weeks GA showed a sustained increase in heart rate; body movement changes occurred at 35 weeks GA. These findings suggest a change in processing of complex sounds at around 33 weeks GA, with responding limited to the acoustic properties of the signal in younger fetuses but attention playing a role in older fetuses. [source]

Growth and Lipid Metabolism in Girls and Young Women with Epilepsy during Pubertal Maturation

EPILEPSIA, Issue 7 2005
Kirsi Mikkonen
Summary:,Purpose: To assess growth and the serum lipid profile in girls with epilepsy receiving monotherapy at a mean age of 12.6 years and approximately 6 years later. Methods: A population-based cohort of 77 girls with epilepsy and 49 healthy controls participated in this follow-up study including two cross-sectional evaluations (age range, 8,18.5 years on the first evaluation, and 12.5,25.8 years on the second evaluation). Forty of the patients were initially taking valproate (VPA), 19, carbamazepine (CBZ), and 18, oxcarbazepine (OXC). Growth data were compiled, body mass index (BMI) was calculated, and serum total (TC), and high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C) cholesterol and triglyceride concentrations were analyzed. Results: Linear growth and final height did not differ between the patients and the controls. At follow-up, the mean BMI of the patients who were off medication (61%) was similar to that of the controls, whereas the patients initially treated with VPA who were still taking any medication had a higher BMI. On the first evaluation, the patients taking VPA had low serum HDL-C, and those taking CBZ or OXC had high serum TC and LDL-C concentrations. At follow-up, serum lipid levels were similar in the patients off medication and the controls. Conclusions: Neither epilepsy nor antiepileptic therapy affects linear growth or final height, but they may have unfavorable effects on body weight and serum lipid concentrations. Lipid-profile impairment seems to be transient if the medication is discontinued. Overweight is common in patients treated with VPA during puberty if epilepsy and medication continue into adulthood. [source]

Requirement of HMGB1 and RAGE for the maturation of human plasmacytoid dendritic cells

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2005
Ingrid
Abstract Dendritic cells (DC) are key components of innate and adaptive immune responses. Plasmacytoid DC (PDC) are a specialized DC subset that produce high amounts of type I interferons in response to microbes. High mobility group box 1 protein (HMGB1) is an abundant nuclear protein, which acts as a potent pro-inflammatory factor when released extracellularly. We show that HMGB1 leaves the nucleus of maturing PDC following TLR9 activation, and that PDC express on the plasma membrane the best-characterized receptor for HMGB1, RAGE. Maturation and type I IFN secretion of PDC is hindered when the HMGB1/RAGE pathway is disrupted. These results reveal HMGB1 and RAGE as the first known autocrine loop modulating the maturation of PDC, and suggest that antagonists of HMGB1/RAGE might have therapeutic potential for the treatment of systemic human diseases. [source]

Maturation of postsynaptic nicotinic structures on autonomic neurons requires innervation but not cholinergic transmission

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2002
Sergio Kaiser
Abstract Postsynaptic development at the neuromuscular junction depends on nicotinic transmission and secreted components from the presynaptic motor nerve terminal. Similarly, secreted components and synaptic activity are both thought to guide development of glutamatergic synapses in the CNS. Nicotinic synapses on chick ciliary neurons are structurally complex: a large presynaptic calyx engulfs the postsynaptic neuron and overlays a series of discrete mats of receptor-rich somatic spines tightly interwoven and folded against the soma. We used fluorescence imaging of ,7-containing nicotinic receptors and the spine constituent drebrin to monitor postsynaptic development. The results show that surgical disruption of the preganglionic input or removal of the ganglionic synaptic target tissue after synapses form in the ganglion does not disrupt the receptor-rich spine mats. Similarly, removal of the target tissue even prior to synapse formation in the ganglion does not prevent subsequent formation of the receptor clusters and associated spine constituents. Postsynaptic development is arrested, however, if normal innervation is prevented by ablating the preganglionic neurons prior to synapse formation. In this case the neurons express reduced levels of nicotinic receptors and cytoskeletal components and organize them only into early-stage clusters. Even low levels of residual innervation, however, can restore much of the normal postsynaptic receptor patterns. Chronic pharmacological blockade of cholinergic synaptic activity fails to replicate the effects of ablating the preganglionic nucleus. The results indicate that ciliary neurons are programmed to express postsynaptic components and can initiate clustering of ,7-containing receptors but need presynaptic guidance for maturation of the postsynaptic structure. [source]

Chronic Hypoxia Delays Myocardial Lactate Dehydrogenase Maturation in Young Rats

EXPERIMENTAL PHYSIOLOGY, Issue 3 2003
Z. Daneshrad
The effect of exposure to hypobaric hypoxia for 4 weeks (oxygen pressure = 106 hPa), equivalent to 5500 m in altitude) on myocardial total lactate dehydrogenase (tLDH) activity and isoform (H and M) composition was comparatively studied in growing (4.5 weeks old) and in adult (4.5 months old) male rats. The consequences of the hypoxia-induced anorexia were checked in growing rats using a pair-fed group. Exposure to hypoxia induced a significant decrease in the H/tLDH ratio in the left (LV) and right ventricle (RV) of growing and adult rats. In adult rats this alteration was mainly a consequence of the significant increase in the specific activity of the M isomer, which resulted in an increase in the overall LDH activity. In contrast, in the LV of young rats exposed to hypoxia, the specific activity of the M isomer was similar to that of normoxic animals while the H isomer activity was significantly lower than in normoxic rats, and the overall LDH activity remained unchanged. These effects were specifically due to hypoxia per se since no significant alterations were observed in pair-fed animals. In the hypertrophied RV, the alteration of H and M isomers following hypoxia was similar to that observed in adults (i.e. no change in H and an increase in M isoform). We conclude that the well-known hypoxia-induced decrease in the H/tLDH ratio is governed by different age-dependent mechanisms. In adult rats, hypoxia may induce in both ventricles a stimulating effect on M isomer expression. In the LV of growing rats this stress could inhibit the H isomer maturation without any effect on the M isomer. In the RV of growing rats this effect could have been counteracted by the growth effect of the hypertrophying process. [source]

Control of oligodendrocyte generation and proliferation by Shp2 protein tyrosine phosphatase

GLIA, Issue 12 2010
Ying Zhu
Abstract Extracellular signals play essential roles in controlling the proliferation and differentiation of oligodendrocyte progenitor cells in the developing central nervous system. However, the intracellular pathways that transduce these extrinsic signals remain to be elucidated. In this study, we showed that conditional ablation of the nonreceptor tyrosine phosphatase Shp2 in Olig1-expressing oligodendrocyte lineage resulted in dramatic reduction in the generation and proliferation of oligodendrocyte progenitor cells in the spinal cord. Maturation and myelination of oligodendrocytes were also compromised in the Shp2 mutants. The deficits in oligodendrocyte development in Shp2 mutants nearly phenocopied those observed in PDGF-A mutants, suggesting that Shp2 is a crucial component in transducing PDGF-A signals in the control of oligodendrocyte proliferation and maturation. © 2010 Wiley-Liss, Inc. [source]

Immunohistochemical expression patterns of AP2, and AP2, in the developing fetal human breast

HISTOPATHOLOGY, Issue 6 2007
N Friedrichs
Aims:, AP2, (TFAP2A) and AP2, (TFAP2G) transcription factors have been implicated in the control of proliferation, differentiation and apoptosis of normal breast epithelium and in breast cancer. The aim of this study was to provide a comprehensive analysis of the expression patterns of TFAP2A and TFAP2G in the developing fetal breast anlage with other relevant markers. Methods and results:, Sixty fetal and one infant human breast specimens from 14 weeks of gestational age to 5 months old were examined. The primary breast outgrowth/nipple showed TFAP2A expression by the basal cells (week 14), followed later by cytokeratin (CK) 5 co-expression (week 17). Sprouting of the secondary outgrowths was characterized by HER-2+ invading cells. Preliminary ductal buds were lined by TFAP2G/HER-1-expressing myoepithelial precursors (week 19). Maturation of TFAP2A/CK18+ epithelia and TFAP2G/smooth muscle actin-positive myoepithelia proceeded in a distal-to-proximal manner beginning in the terminal end buds (week 22). CK5+ progenitor cells and CK5/TFAP2A or CK5/TFAP2G co-expressing intermediary glandular or myoepithelial cells were found in the terminal end buds of neonatal fetal breast tissue. Conclusions:, AP2 transcription factors may play decisive pacemaker roles in initiating and coordinating budding and branching processes during formation of the fetal breast anlage, possibly via modulation of an epidermal growth factor receptor. [source]

Development of Tactile Responses in Human Preterm and Full-Term Infants From 30 to 40 Weeks Postconceptional Age

INFANCY, Issue 1 2002
Isabel Fearon
Maturation of tactile sensitivity prior to term was examined in 36 preterm and 13 full-term infants using a fixed-trial, habituation procedure. Each infant was presented with a series of 8 habituation (arm stroke), 2 novel (arm lift), and 2 recovery (arm stroke) stimulus trials while heart rate and body movements were recorded. Maturation was observed with a gradual increase in the magnitude of the stimulus-elicited cardiac acceleration and cardiac-movement coupling from 30 to 40 weeks postconceptional age. The majority of infants displayed habituation,an excitatory response (heart rate acceleration and body movement),to the initial presentation of a tactile stimulus, response decline with repeated stimulations, and renewed response to a novel stimulus. A substantial number of infants (40%) failed to respond initially to the tactile stimulus, increased responding over several stimulus presentations, and failed to discriminate the presentation of a novel stimulus. We speculate that these differences in response patterns observed over all ages represent individual difference in the perception of stimulus intensity. [source]

Reproductive status in females of the Brazilian catfish, Pseudoplatystoma fasciatum reared in cages

JOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2010
E. Romagosa
Summary The distinctive morphological features of the ovaries the ,cachara', Pseudoplatystoma fasciatum were characterized macroscopically, and by histology, when reared in cages, from March 2005 to February 2006. Forty eight females (mean total weight = 2.7 kg, mean standard length = 65.1 cm) were allocated to four cages of 2.7 m3 (20 fish/cage) which were installed in four 600 m2 ponds, located at the IP, Pariquera-Açu, São Paulo, Brazil. The monthly, samples were fixed in 4%-buffered formalin before preparation for histological examination, ovaries were removed and weighted. The gonadosomatic index (GSI) was calculated as = 100 × weight ovaries/total fish weight. The ovaries are the cystovarian type and macroscopically, were established three stages of ovarian maturation: Resting, developing Maturation (initial, intermediate, final) and Regression (initial, intermediate, final). Based on morphological criteria of those ovaries, the oocyte development has been divided into distinct stages: (i) oocyte growth (vitellogenesis); (ii) oocyte maturation, along which it goes through different phases of development, before (iii) ovulation and, (iv) spawning. When the P. fasciatum were kept in confinement and not induced to breed occurs fail to attain final oocyte maturation, start the process of degeneration. Consequently, the weight started to decline and 45% of the ovaries showed atresia of vitellogenic follicles. This was considered indicative of a recent cessation of the reproductive activity. Such failure could have been caused by stress of the monthly sampling involving a certain degree of disturbance, and perhaps also by the existence of stressors while in captivity. The synchronous ovary contained oocytes in an unique stage of development and had potential to perform total spawning up to one time a year, with the period reproductive beginning in the end of November to the beginning of February, coinciding with the highest water temperatures in the experimental cages (29.0,31.5°C) and the increase of mean values of GSI. During the regression phase, residual oocytes could be observed together with decrease of the mean values of GSI and, the temperatures. [source]

Maspin Is Involved in Bone Matrix Maturation by Enhancing the Accumulation of Latent TGF-,,,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2007
Reiko Tokuyama
Abstract Maspin, a serine protease inhibitor, is expressed by formative osteoblasts. The repression of maspin expression in osteoblastic cells decreased the level of latent TGF-, in the extracellular matrix, whereas the overexpression of maspin increased latent TGF-,. These findings suggest that maspin plays an important role in bone matrix formation, particularly in the accumulation of latent TGF-,. Introduction: Maspin is a serine protease inhibitor that exhibits tumor suppressive and anti-angiogenic activities. This study was performed to elucidate a possible role for maspin in bone formation. Materials and Methods: We performed immunohistochemical analysis of the expression of maspin during endochondral ossification. We evaluated the expression of maspin mRNA and protein in ROS 17/2.8 cells and primary rat osteoblastic cells by RT-PCR, immunocytochemistry, and Western blot analysis. We also examined the accumulation of TGF-, in the extracellular matrix of cultured ROS 17/2.8 cells after transfection with vectors expressing either maspin or maspin antisense. Results: We observed expression of maspin by active osteoblasts in vivo. Rat osteoblastic cells also expressed maspin mRNA and protein in vitro. Moreover, the accumulation of latent TGF-, in the extracellular matrix significantly decreased in cultures exposed to an anti-maspin antibody and when cells were transfected with a maspin antisense-expressing vector. In contrast, accumulation of latent TGF-, in the extracellular matrix increased after transfection of cells with a vector expressing maspin. Conclusions: These findings suggest that maspin expressed in active osteoblasts plays an important physiological role during maturation of the bone matrix, and in particular, during the process of accumulation of latent TGF-, in the extracellular matrix. [source]

Smad3-Deficient Chondrocytes Have Enhanced BMP Signaling and Accelerated Differentiation,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2006
Tian-Fang Li
Abstract Smad3 deficiency accelerates chondrocyte maturation and leads to osteoarthritis. Primary chondrocytes without Smad3 lack compensatory increases of TGF-, signaling factors, but BMP-related gene expression is increased. Smad2 or Smad3 overexpression and BMP blockade abrogate accelerated maturation in Smad3,/, chondrocytes. BMP signaling is increased in TGF-, deficiency and is required for accelerated chondrocyte maturation. Introduction: Disruption of TGF-, signaling results in accelerated chondrocyte maturation and leads to postnatal dwarfism and premature osteoarthritis. The mechanisms involved in this process were studied using in vitro murine chondrocyte cultures. Materials and Methods: Primary chondrocytes were isolated from the sterna of neonatal wildtype and Smad3,/, mice. Expressions of maturational markers, as well as genes involved in TGF-, and BMP signaling were examined. Chondrocytes were treated with TGF-, and BMP-2, and effects on maturation-related genes and BMP/TGF-, responsive reporters were examined. Recombinant noggin or retroviral vectors expressing Smad2 or Smad3 were added to the cultures. Results: Expression of colX and other maturational markers was markedly increased in Smad3,/, chondrocytes. Smad3,/, chondrocytes lacked compensatory increases in Smad2, Smad4, TGFRII, Sno, or Smurf2 and had reduced expression of TGF - ,1 and TGFRI. In contrast, Smad1, Smad5, BMP2, and BMP6 expression was increased, suggesting a shift from TGF-, toward BMP signaling. In Smad3,/, chondrocytes, alternative TGF-, signaling pathways remained responsive, as shown by luciferase assays. These non-Smad3-dependent TGF-, pathways reduced colX expression and alkaline phosphatase activity in TGF-,-treated Smad3,/, cultures, but only partially. In contrast, Smad3,/, chondrocytes were more responsive to BMP-2 treatment and had increased colX expression, phosphoSmads 1, 5, and 8 levels, and luciferase reporter activity. Overexpression of both Smad2 and Smad3 blocked spontaneous maturation in Smad3-deficient chondrocytes. Maturation was also abrogated by the addition of noggin, an extracellular BMP inhibitor. Conclusions: These findings show a key role for BMP signaling during the chondrocyte maturation, occurring with loss of TGF-, signaling with important implications for osteoarthritis and cartilage diseases. [source]

Expression of FGFR3 with the G380R Achondroplasia Mutation Inhibits Proliferation and Maturation of CFK2 Chondrocytic Cells

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2000
Janet E. Henderson
Abstract A G380R substitution in the transmembrane-spanning region of FGFR3 (FGFR3Ach) results in constitutive receptor kinase activity and is the most common cause of achondroplastic dwarfism in humans. The epiphyseal growth plates of affected individuals are disorganized and hypocellular and show aberrant chondrocyte maturation. To examine the molecular basis of these abnormalities, we used a chondrocytic cell line, CFK2, to stably express the b variant of wild-type FGFR3 or the the constitutively active FGFR3Ach. Overexpression of FGFR3 had minimal effects on CFK2 proliferation and maturation compared with the severe growth retardation found in cells expressing FGFR3Ach. Cells expressing the mutant receptor also showed an abnormal apoptotic response to serum deprivation and failed to undergo differentiation under appropriate culture conditions. These changes were associated with altered expression of integrin subunits, which effectively led to a switch in substrate preference of the immature cell from fibronectin to type II collagen. These in vitro observations support those from in vivo studies indicating that FGFR3 mediates an inhibitory influence on chondrocyte proliferation. We now suggest that the mechanism is related to altered integrin expression. [source]

Maturational Atrioventricular Nodal Physiology in the Mouse

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2000
COLIN T. MAGUIRE B.S.
Mouse AV Nodal Maturation. Introduction: Dual AV nodal physiology is characterized by discontinuous conduction from the atrium to His bundle during programmed atrial extrastimulus testing (A2V2 conduction curves), AV nodal echo beats, and induction of AV nodal reentry tachycardia (AVNRT). The purpose of this study was to characterize in vivo murine maturational AV nodal conduction properties and determine the frequency of dual AV nodal physiology and inducible AVNRT. Methods and Results: A complete transvenous in vivo electrophysiologic study was performed on 30 immature and 19 mature mice. Assessment of AV nodal conduction included (1) surface ECG and intracardiac atrial and ventricular electrograms; (2) decremental atrial pacing to the point of Wenckebach block and 2:1 conduction; and (3) programmed premature atrial extrastimuli to determine AV effective refractory periods (AVERP), construct A2V2 conduction curves, and attempt arrhythmia induction. The mean Wenckebach block interval was 73 ± 12 msec, 2:1 block pacing cycle length was 61 ± 11 msec, and mean AVERP100 was 54 ± 11 msec. The frequency of dual AV nodal physiology increased with chronologic age, with discontinuous A2V2, conduction curves or AV nodal echo heats in 27% of young mice < 8 weeks and 58% in adult mice (P = 0.03). Conclusion: These data suggest that mice, similar to humans, have maturation of AV nodal physiology, hut they do not have inducible AVNRT. Characterization of murine electrophysiology may be of value in studying genetically modified animals with AV conduction abnormalities. Furthermore, extrapolation to humans may help explain the relative rarity of AVNRT in the younger pediatric population. [source]

Changes in Radical-scavenging Activity and Components of Mulberry Fruit During Maturation

JOURNAL OF FOOD SCIENCE, Issue 1 2006
Tomoyuki Oki
ABSTRACT Extracts of mulberry fruits (Morus sp.) were prepared from 8 cultivars harvested at 4 stages of maturity, and their radicalscavenging activity, anthocyanin content, and total phenolic content were measured. The radical-scavenging activity was evaluated by a spectrophotometric assay using the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) in a 96-well microplate. Mulberry fruit extracts exhibited the DPPH-scavenging activities, ranging from 2.5 to 20.3 ,mol-Trolox equiv/g-FW. Their activities were variable during maturation, and the highest activity was observed in the fully mature mulberry fruit in all cultivars. Anthocyanin was scarcely present in the immature mulberry fruits; however, its content increased as the fruit matured in all cultivars. On the other hand, all immature mulberry fruits contained non-anthocyanin phenolic compound. An on-line high-performance liquid chromatography (HPLC) method for the detection of DPPH-scavenging compounds revealed the difference in predominant radical scavengers between the immature and fully mature stages in the Miran 5 cultivar. Four major radical scavengers in the Miran 5 cultivar were assigned to 2 caffeoylquinic acids (chlorogenic acid and its isomer) and 2 anthocyanins (cyanidin 3-glucoside and cyanidin 3-rutinoside) in the immature and fully mature stages, respectively, by LC-ESI-MS/MS analysis. The change in the content of 4 compounds in mulberry fruits during maturation demonstrated that the most likely contributors to the DPPH-scavenging activity were caffeoylquinic acids in the immature mulberry and anthocyanins in the mature and fully mature mulberry. [source]

Changes in Basal Hypothalamic Chicken Gonadotropin-Releasing Hormone-I and Vasoactive Intestinal Polypeptide Associated with a Photo-Induced Cycle in Gonadal Maturation and Prolactin Secretion in Intact and Thyroidectomized Starlings (Sturnus vulgaris)

JOURNAL OF NEUROENDOCRINOLOGY, Issue 7 2002
A. Dawson
Abstract Chicken gonadotropin-releasing hormone-I (GnRH-I) and the avian prolactin-releasing hormone, vasoactive intestinal polypeptide (VIP), were measured in the basal hypothalamus in male starlings during photo-induced gonadal growth and the subsequent development and maintenance of reproductive photorefractoriness. Comparisons were made with thyroidectomized birds, which maintain breeding condition irrespective of changes in photoperiod. In intact birds, basal hypothalamic GnRH-I increased four-fold after photostimulation and then decreased 115-fold over 12 weeks to values characteristic of long-term photorefractoriness. Pituitary and plasma prolactin increased after photostimulation, reaching peak values when the testes were regressing, and returned to low values in long-term photorefractory birds. Basal hypothalamic VIP did not change after photostimulation in intact birds. In photostimulated thyroidectomized birds, values for basal hypothalamic GnRH-I and VIP, and for pituitary and plasma prolactin, remained no different to those of nonphotostimulated intact birds. These observations confirm that reproductive photorefractoriness is related to a decrease in hypothalamic GnRH-I. However, photorefractoriness in terms of prolactin secretion is not similarly related to a decrease in basal hypothalamic VIP. The mechanisms responsible for the decrease in prolactin in long-term photorefractory birds and for the total lack of photoperiodic responses in thyroidectomized birds remain unresolved. [source]

New frontiers of assisted reproductive technology (Chien Tien Hsu Memorial Lecture 2007)

JOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 1 2009
P. C. Ho
Abstract Many significant advances have been made in assisted reproductive technology since the birth of the first baby conceived with in vitro fertilization and embryo transfer. The development of recombinant gonadotropins and gonadotropin releasing hormone antagonists helps to simplify the ovarian stimulation. Excessive ovarian stimulation should be avoided because of the risks of ovarian hyperstimulation syndrome and reduction in endometrial receptivity. Maturation of oocytes in vitro has been developed in some centers. It is still uncertain whether techniques such as assisted hatching, blastocyst transfer and pre-implantation aneuploidy screening can improve the live birth rates in assisted reproduction. The introduction of pre-implantation genetic diagnosis for selection of human lymphocyte antigens (HLA) compatible embryos for treatment of siblings has raised ethical concerns. There is a higher risk of obstetric complications and congenital abnormalities even in singleton pregnancies achieved with assisted reproduction. Because of the risks of multiple pregnancies, elective single embryo transfer is increasingly used in good-prognosis patients. With a good freezing program, the cumulative pregnancy rate (including the pregnancies from subsequent replacement of frozen-thawed embryos) is not adversely affected. Improvement in cryopreservation techniques has made it possible to cryopreserve slices of ovarian tissue or oocytes, thus helping women who have to receive sterilizing forms of anti-cancer treatment to preserve their fertility. It is important that the development of the new techniques should be based on good scientific evidence. Ethical, legal and social implications should also be considered before the introduction of new techniques. [source]

Additive Inhibition of Dendritic Cell Allostimulatory Capacity by Alcohol and Hepatitis C Is Not Restored by DC Maturation and Involves Abnormal IL-10 and IL-2 Induction

ALCOHOLISM, Issue 6 2003
Angela Dolganiuc
Background: Excessive alcohol use results in impaired immunity, and it is associated with increased incidence and progression of chronic hepatitis C virus (HCV) infection. Here we investigated the effects of HCV infection and alcohol on myeloid dendritic cells (DC) that are critical in antiviral immunity. Methods: Immature and mature DCs were generated from monocytes of chronic HCV infected patients (HCV-DC) and controls (N-DC) with IL-4 plus granulocyte-macrophage colony stimulating factor (GM-CSF) in the presence or absence of alcohol (25 mM). DC allostimulatory capacity was tested in mixed lymphocyte reaction (MLR) and cytokine production by ELISA. Results: Allostimulatory capacity of HCV-DCs was reduced compared to N-DCs and it was further inhibited by alcohol treatment (p < 0.01). MLR was also decreased with alcohol-treated N-DCs. DC phenotypic markers and apoptosis were comparable between HCV-DCs and N-DCs irrespective of alcohol treatment. However, HCV-DCs and alcohol-treated N-DCs exhibited elevated IL-10 and reduced IL-12 production. Reduced MLR with HCV-DCs and its further inhibition by alcohol coexisted with decreasing IL-2 levels (p < 0.017). DC maturation partially improved but failed to fully restore the reduced allostimulatory function of either alcohol-treated or alcohol-naïve HCV-DCs (p < 0.018). Conclusions: Alcohol and HCV independently and together inhibit DC allostimulatory capacity, increase IL-10, reduce IL-12 and IL-2 production that cannot be normalized by DC maturation. HCV and alcohol interact to modulate innate and adaptive immune responses via dendritic cells. [source]

Growth, Maturation, Induced Spawning, and Production of the First Generation of South American Catfish, Pseudoplatystoma sp., in North America

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2008
Konrad Dabrowski
Growth, plasma steroids, and the appearance of gonads (histology and gonadosomatic index) were followed in South American catfish (surubim, Pseudoplatystoma sp.) raised in captivity in the aquaculture facility at The Ohio State University, Columbus, Ohio, USA, from 2003 until 2006. Broodstock growth showed a great individual variation and it did not seem sex dependent. The levels of 11-ketotestosterone were high in males during the reproductive season. Three out of six females spawned after receiving two doses of carp pituitary extract (0.5 and 5 mg/kg) at 11-h intervals. Fertilization was performed in only one female in February 2006. Egg size was 0.73 ± 0.06 mm in diameter at stripping. Two males released sperm, and it was used for fertilization. Sperm concentrations were 24 × 109 and 15.5 × 109 spermatozoa/mL in Male 1 and Male 2, respectively, and viability was confirmed after activation in 0.3% NaCl. Embryo survival at 9 h after fertilization was 44 and 23% for Male 1 and Male 2, respectively. Embryos hatched 15 h after fertilization. Larvae were 3.53 ± 0.09 mm in length at hatching and were successfully raised (72% survival after 2 wks) using live brine shrimp nauplii. [source]

Properties of the hepatitis C virus core protein: a structural protein that modulates cellular processes

JOURNAL OF VIRAL HEPATITIS, Issue 1 2000
McLauchlan
The core protein of hepatitis C virus (HCV) is believed to form the capsid shell of virus particles. Maturation of the protein is achieved through cleavage by host cell proteases to give a product of 21 000 MW, which is found in tissue culture systems and sera from infected individuals. However, efficient propagation of the virus is not possible at present in tissue culture. Hence, studies have focused on the properties of the core protein and its possible role in pathologies associated with HCV infection. This review describes key features of the polypeptide and the status of current knowledge on its ability to influence several cellular processes. [source]

Early production of thymic stromal lymphopoietin precedes infiltration of dendritic cells expressing its receptor in allergen-induced late phase cutaneous responses in atopic subjects

ALLERGY, Issue 7 2009
C. J. Corrigan
Background:, Thymic stromal lymphopoietin (TSLP) is an interleukin (IL)-7-like cytokine that triggers dendritic cell-mediated T helper (Th)2 inflammatory responses through a receptor consisting of a heterodimer of the IL-7 receptor alpha (IL-7R,) chain and the TSLP receptor (TSLPR), which resembles the cytokine receptor common gamma chain. Dendritic cells activated by TSLP prime development of CD4+ T cells into Th2 cells contributing to the pathogenesis of allergic inflammation. We hypothesized that allergen exposure induces expression of TSLP and results in recruitment of TSLPR bearing cells in the cutaneous allergen-induced late-phase reaction (LPR) in atopic subjects. Methods:, Skin biopsies were obtained from atopic subjects (n = 9) at various times after cutaneous allergen challenge. In situ hybridization and immunohistochemistry were used to determine TSLP mRNA expression and to measure infiltration of TSLPR+ DC in skin LPR. RT-PCR and flow cytometry were employed to analyse TSLPR expression on isolated blood DC. Results:, Allergen-induced skin TSLP expression occurred as early as 1 h after allergen challenge, whereas TSLPR+ and CD11c+ cells infiltrated relatively late (24,48 h). The majority of TSLPR+ cells were DC co-expressing blood DC antigen-1 (BDCA-1) or BDCA-2. Freshly isolated blood DC expressed both TSLPR and IL-7R, chains. Maturation and stimulation with TSLP or polyriboinosinic,polyribocytidylic acid in vitro upregulated the expression of both TSLPR and IL-7R, chains in DC but not in chemoattractant receptor-homologous molecule expressed on Th2 cells+ CD4+ T cells. Conclusion:, The data suggest that TSLP plays a role in augmenting, through DC recruitment and activation, the development of Th2-type T cells in allergic inflammation. [source]

Influence of oocyte collection technique on initial chromatin configuration, meiotic competence, and male pronucleus formation after intracytoplasmic sperm injection (ICSI) of equine oocytes,

MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 1 2001
Maria Elena Dell'Aquila
Abstract There is a great variability in the success of horse oocyte maturation and fertilization among laboratories. This study was conducted to determine if the meiotic and developmental competence of horse oocytes could be dependent on the method of oocyte collection, i.e., aspiration of follicular fluid with a vacuum apparatus, or opening follicles and scraping the granulosa layer. Horse oocytes were recovered from abattoir ovaries by aspiration or scraping and classified as having compact (Cp), expanded (Ex), or partial (P) cumuli. In Experiment 1 (Part A in May and Part B in October), oocytes were fixed immediately after collection to assess whether the collection method influenced the initial chromatin configuration of oocytes. In Experiment 2, in vitro maturation rates of oocytes recovered by aspiration or scraping were compared. In Experiment 3, oocytes were matured in vitro and submitted to intracytoplasmic sperm injection (ICSI). Initial chromatin configuration differed according to collection method in that there was a significantly higher prevalence of diffuse chromatin within the germinal vesicle in oocytes recovered by scraping than in oocytes recovered by aspiration (29/87, 33% and 28/166, 17%, respectively; P,<,0.01). Maturation of oocytes to metaphase II did not significantly differ between scraped and aspirated oocytes (56/101, 55.4 % vs. 65/106, 61.4%, respectively). The overall pronucleus formation rate after ICSI of oocytes recovered by scraping was not significantly different than that of oocytes recovered by aspiration (50/99, 52.6% vs. 50/85, 68.5 %, respectively); however, the rate of abnormal fertilization was significantly higher for oocytes collected by aspiration (14/73, 19% vs. 6/94, 6%, respectively; P,<0.05). These results demonstrate that the collection method affects the population of recovered oocytes and may contribute to differences in results observed among laboratories working with horse oocytes. Mol. Reprod. Dev. 60: 79,88, 2001. © 2001 Wiley-Liss, Inc. [source]

Histopathologic Maturation of Juvenile Xanthogranuloma in a Short Period

PEDIATRIC DERMATOLOGY, Issue 2 2001
Yumiko Kubota M.D.
The initial biopsy specimen showed a dense collection of small histiocytes as evidenced by CD68 staining without either lipidization or giant cell formation, admixed with a small number of lymphocytes. On the other hand, sections from the excised specimen obtained 2 weeks after the initial biopsy from the same site showed a mixed proliferation of abundant foam cells together with Touton giant cells, some small histiocytes, and small numbers of lymphocytes and eosinophils. Mitotic figures were fewer in the excised nodule than in the initial biopsy specimen. Fascicles of spindle-shaped cells arranged in a vague storiform pattern were additionally found in the deep portion of the nodule. Our case findings suggest that xanthomatization of the JXG could have been accelerated by the inflammation associated with the biopsy, based on the histopathologic fact that the change from an early phase to a mature form occurred within the very short period of 2 weeks. [source]