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Relative Volume (relative + volume)
Selected AbstractsThe evolution of hippocampus volume and brain size in relation to food hoarding in birdsECOLOGY LETTERS, Issue 12 2004László Zsolt Garamszegi Abstract Food-hoarding birds frequently use spatial memory to relocate their caches, thus they may evolve a larger hippocampus in their brain than non-hoarder species. However, previous studies testing for such interspecific relationships provided conflicting results. In addition, food hoarding may be a cognitively complex task involving elaboration of a variety of brain regions, even outside of the hippocampus. Hence, specialization to food hoarding may also result in the enlargement of the overall brain. In a phylogenetic analysis of distantly related birds, we studied the interspecific association between food hoarding and the size of different brain regions, each reflecting different resolutions. After adjusting for allometric effects, the relative volume of the hippocampus and the relative size of the entire brain were each positively related to the degree of food-hoarding specialization, even after controlling for migration and brood parasitism. We also found some significant evidence for the relative volume of the telencephalon being associated with food hoarding, but this relationship was dependent on the approach we used. Hence, neural adaptation to food hoarding may favour the evolution of different brain structures. [source] Villous trophoblast growth in pregnancy at high altitudeJOURNAL OF ANATOMY, Issue 5 2002T. M. Mayhew The trophoblastic epithelium of placental villi exhibits continuous turnover. Phases of proliferation, recruitment, maturation, terminal differentiation (apoptosis) and extrusion exist in steady state and occur in distinctive spatial compartments, viz. cytotrophoblast cells (CT), syncytiotrophoblast (ST), syncytial knots (SK), denudation sites (DEN) and syncytial fragments. Hypoxia in vitro stimulates CT proliferation but inhibits recruitment into ST. Pregnancy at high altitude (HA) is associated with reduced birthweight and provides a convenient model of preplacental (hypobaric) hypoxia. HA placentas show impoverished villous growth and changes in the incidences of CT cells and SK regions. Here we examine placentas from Amerindian and nonindigenous women who completed full-term pregnancies at low altitude (LA; 400 m; n = 25) and high altitude (HA; 3600 m; n = 45) in Bolivia. We test the hypothesis that HA pregnancy disturbs the epithelial steady state as reflected in the relative volumes and surfaces of trophoblast compartments. Masson trichrome stained tissue sections and microscopical fields were generated by uniform random sampling. Point and intersection counts were used to estimate the volumes and surface areas of nonsyncytial knots (nonSK), SK regions, syncytial bridges (SB) and denudation sites (DEN). Absolute values were compared by 2-way analyses of variance to resolve altitudinal from ethnic effects. At LA, trophoblast comprised about 85% nonSK, 8% SK, 5% SB and 3% CT by volume. Its maternal surface area comprised about 91% nonSK, 5% SK, 2% SB, and 3% DEN. Apart from CT (the fractional volume of which increased to 4%, P < 0.05), relative volumes of trophoblast compartments did not alter significantly at HA. However, there was a roughly 30% reduction in absolute volume of trophoblast at HA (P < 0.001) which could be explained mainly by a decrease in volume of nonSK regions (P < 0.001). The volume of CT was unaltered. Absolute surface areas of villi also declined at HA (by 20%, P < 0.01) and, again, this was attributed mainly to nonSK. The findings confirm that poor villous growth is partly due to failure of trophoblast to attain the growth seen at LA. The reduced trophoblastic growth occurs despite an increase in relative volume of CT cells (consistent with previously reported increases in proliferative activity) and, probably, by a combination of compromised syncytial fusion and continuing extrusion of syncytial fragments. [source] The Relationship Between Endocardial Voltage and Regional Volume in Electroanatomical Remodeled Left Atria in Patients with Atrial Fibrillation: Comparison of Three-Dimensional Computed Tomographic Images and Voltage MappingJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2009JAE HYUNG PARK B.Sc. Background: Long-standing atrial fibrillation (AF) changes left atrial (LA) morphology, and the LA size is related to recurrence after radiofrequency catheter ablation (RFCA). We hypothesize that LA morphology, based on embryological origin, affects the outcome of RFCA. Methods: We analyzed 3D computed tomographic (CT) images of LA in 70 patients with AF (54 males, 55.6 ± 10.5 years old, paroxysmal AF (PAF):persistent AF (PeAF) = 32:38) who underwent RFCA. Each LA image was divided into venous atrium (VA), anterior LA (ALA), LA appendage (LAA), and both antrum. Absolute and relative volumes were calculated, and the lengths of linear ablation sites were measured. Results: (1) In patients with the mean LA voltage , 2.0 mV, LA volume, especially ALA, was larger (P < 0.01) compared to those with LA voltage > 2.0 mV. (2) The total LA volume was significantly larger (P < 0.01) and LAA voltages (P < 0.05) and conduction velocities (P < 0.05) were lower in patients with PeAF than in those with PAF. (3) In patients with recurrence, LA volume was generally larger (P < 0.01) than in those without recurrence. In PAF patients with recurrence, the relative volume of ALA was significantly larger (P < 0.01) than those without recurrence. Conclusions Morphologically remodeled LA has low endocardial voltage, and enlargement of ALA is more significant in electroanatomically remodeled LA. The disproportional enlargement of ALA was observed more often in PAF patients with recurrence after ablation than those without recurrence. [source] Dissipation of inclusions in HgCdTe/CdTe films under the influence of laser shock wavesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2004Vitaly Yakovyna Abstract Using HgCdTe/CdTe structures as an example, the study of the effect of laser shock waves on the narrow-gap semiconductors with high density of inhomogeneties as well as on the epitaxial layer/substrate interface are presented. It is found that laser shock wave treatment is an effective way to reduce the relative volume of precipitates in semiconductors. The technique is very promising for developing a low-temperature tool for modification of device structures parameters. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A Discussion of the Kamlet-Jacobs Formula for the Detonation PressurePROPELLANTS, EXPLOSIVES, PYROTECHNICS, Issue 1 2006Luc Kazandjian Abstract The main features of the Kamlet-Jacobs formula for the detonation pressure of CHNO explosives are analytically derived from a BKW (Becker-Kistiakowsky-Wilson) equation of state of the detonation products. In the derivation, well-known typical values at the Chapman-Jouguet state, in particular the nearly constant value of the relative volume of the detonation products, are used. [source] Short-Term Antiandrogen Flutamide Treatment Causes Structural Alterations in Somatic Cells Associated with Premature Detachment of Spermatids in the Testis of Pubertal and Adult Guinea PigsREPRODUCTION IN DOMESTIC ANIMALS, Issue 3 2010LR Maschio Contents In spite of widespread application of flutamide in the endocrine therapies of young and adult patients, the side effects of this antiandrogen on spermatogenesis and germ-cell morphology remain unclear. This study evaluates the short-term androgen blockage effect induced by the administration of flutamide to the testes of pubertal (30-day old) and adult (65- and 135-day old) guinea pigs, with an emphasis on ultrastructural alterations of main cell types. The testes removed after 10 days of treatment with either a non-steroidal antiandrogen, flutamide (10 mg/kg of body weight) or a pharmacological vehicle alone were processed for histological, quantitative and ultrastructural analysis. In pubertal animals, flutamide androgenic blockage induces spermatogonial differentiation and accelerates testes maturation, causing degeneration and detachment of primary spermatocytes and round spermatids, which are subsequently found in great quantities in the epididymis caput. In post-pubertal and adult guinea pigs, in addition to causing germ-cell degeneration, especially in primary spermatocytes, and leading to the premature detachment of spherical spermatids, the antiandrogen treatment increased the relative volume of Leydig cells. In addition, ultrastructural evaluation indicated that irrespective of age antiandrogen treatment causes an increase in frequency of organelles involved with steroid hormone synthesis in the Leydig cells and a dramatic accumulation of myelin figures in their cytoplasm and, to a larger degree, in Sertoli cells. In conclusion, the transient exposition of the guinea pigs to flutamide, at all postnatal ages causes some degenerative lesions including severe premature detachment of spermatids and accumulation of myelin bodies in Leydig and Sertoli cells, compromising, at least temporarily, the spermatogenesis. [source] Characteristics of Rabbit Transgenic Mammary Gland Expressing Recombinant Human Factor VIIIANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2009P. Chrenek Summary The objective of this research was to compare (i) the content of milk protein and recombinant human factor VIII (rhFVIII) in the milk of transgenic and non-transgenic rabbit females at three lactations and (ii) histological structure, ultrastructural morphology and occurrence of apoptosis in rabbit transgenic and non-transgenic mammary gland during third lactation and involution. Significant differences (t0.05) in milk protein content were found between transgenic and non-transgenic at all three lactations. The percentage of apoptotic cells was significantly higher (t0.01) in non-transgenic ones compared with transgenic mammary gland tissues (6.5% versus 2.4%) taken at the involution stage. Morphometrical analysis of histological preparations at the involution stage detected a significantly higher (t0.05) relative volume of lumen in transgenic animals compared with non-transgenic ones (60.00 versus 46.51%). Ultrastructural morphology of the transgenic mammary gland epithelium at the involution stage revealed an increased relative volume of protein globules (t0.05); at the lactation stage, a significantly higher volume of mitochondria (13.8%) compared with the non-transgenic (9.8%) ones was observed. These results, although revealing differences in some parameters of ultrastructure and histology, indicate no harmful effect of the mouse whey acid protein-hFVIII transgene expression on the state of mammary gland of transgenic rabbit females. [source] Ultrastructural Morphometry of Mammary Gland in Transgenic and Non-transgenic RabbitsANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2006S. Dragin Summary The mammary gland of transgenic animals has been used for the production of recombinant proteins of therapeutic and nutraceutical use. The objective of this study was to compare the ultrastructure of transgenic and non-transgenic rabbit mammary gland tissue. New Zealand White transgenic rabbits were obtained by breeding non-transgenic rabbits with transgenic founder rabbits containing a whey acidic protein-human factor VIII (WAP-hFVIII) transgene integrated into their genome. Samples of mammary gland tissue from lactating rabbit females were isolated by surgical procedures. These samples were examined by optical and electron microscopy and photographs were taken. Measurements of ultrastructural organelles were made from digital images of the mammary cells. No differences were found in the cellular structure of mammary tissue, but significant differences t(0.001) in the relative volume of mitochondria and vacuoles between transgenic and non-transgenic mammary gland epithelium were observed. [source] INVESTIGATION OF THE MICROCIRCULATION AND THE STATE OF OXIDATIVE STRESS IN THE RAT AFTER SCORPION ENVENOMATIONCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 4 2007Z Sahnoun SUMMARY 1Severe cases of scorpion envenomation (SE) generally show both respiratory and cardiocirculatory dysfunction. However, the pathophysiology of SE remains controversial. In the present study, we tried to explain the pathophysiology of the haemodynamic perturbations and cardiac failure in rats poisoned by the venom of Buthus occitanus tunetanus through a histomorphometric study of myocardial and muscular skeletal microcirculation and analysis of the oxidative stress state in order to evaluate the implication of the inflammatory process in the pathogenesis of SE. 2Experiments were performed on 96 rats divided into 16 groups (n = 6 in each group). Two groups were used to determine the optimum conditions of venom administration and times when to measure haemodynamic parameters. The B. occitanus tunetanus venom was administered at a dose of 800 µg/kg and tissues were removed 5 and 20 min after envenomation. Six groups were used for histomorphometric study: two control groups, two poisoned groups an two melatonin-pretreated and poisoned groups. The histomorphometric study was performed on isolated hearts and skeletal muscles. The final eight groups of rats (two control groups, two envenomated groups, two control groups pretreated with melatonin and two groups pretreated and envenomated) were used to investigate the state of tissue oxidative stress during SE and to evaluate the anti-oxidant effect of melatonin on rats poisoned with B. occitanus tunetanus venom. This study was based on the determination of tissue malondialdehyde in isolated organs as an indicator of thiobarbituric acid-reactive substances (TBARS). Melatonin was injected at a dose of 5 mg/kg, i.v., 15 min before the administration of serum or venom. Data were compared using analysis of variance and Tukey's test for multiple pair-wise comparisons. 3Five minutes after venom injection, a significant reduction in the mean relative volume of venules and arterioles in the heart and skeletal muscles of poisoned rats was noted. Twenty minutes after venom injection, these volumes were significantly increased in the heart and skeletal muscles of poisoned rats. Pretreatment of envenomated rats with melatonin resulted in a significant decrease in the mean relative volume of the venules and arterioles in the heart and skeletal muscles 5 and 20 min after venom injection compared with untreated envenomated rats. Investigation of the oxidative stress state showed a highly significant increase in TBARS in poisoned rats compared with control groups 5 and 20 min after venom injection. Melatonin pretreatment of rats poisoned with B. occitanus tunetanus venom resulted in an important and highly significant reduction of TBARS compared with untreated envenomated rats. 4It appears from the results of the present study that administration of B. occitanus tunetanus venom engendered an excessive myocardial and skeletal muscular vasoconstriction attributed to massive catecholamine release followed by arteriolar and venular vasodilatation. This venous stasis at the muscular microcirculation could be due to myocardiac failure. However, the concomitant presence of arteriolar vasodilatation suggests an inflammatory process in the pathophysiology of SE. This process was suggested by the genesis of a state of oxidative stress in relation to the important lipoperoxidation, which was inhibited by administration of the anti-oxidant melatonin. Thus, melatonin pretreatment seemed to accentuate the first phase of vascular reactivity in envenomed rats and inhibit the second vasodilator phase observed 20 min after administration of the venom. [source] Development of cortical and subcortical brain structures in childhood and adolescence: a structural MRI studyDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 1 2002Elizabeth R Sowell PhD The purpose of the present study was to describe in greater anatomical detail the changes in brain structure that occur during maturation between childhood and adolescence. High-resolution MRI, tissue classification, and anatomical segmentation of cortical and subcortical regions were used in a sample of 35 normally developing children and adolescents between 7 and 16 years of age (mean age 11 years; 20 males, 15 females). Each cortical and subcortical measure was examined for age and sex effects on raw volumes and on the measures as proportions of total supratentorial cranial volume. Results indicate age-related increases in total supratentorial cranial volume and raw and proportional increases in total cerebral white matter. Gray-matter volume reductions were only observed once variance in total brain size was proportionally controlled. The change in total cerebral white-matter proportion was significantly greater than the change in total cerebral gray-matter proportion over this age range, suggesting that the relative gray-matter reduction is probably due to significant increases in white matter. Total raw cerebral CSF volume increases were also observed. Within the cerebrum, regional patterns varied depending on the tissue (or CSF) assessed. Only frontal and parietal cortices showed changes in gray matter, white matter, and CSF measures. Once the approximately 7% larger brain volume in males was controlled, only mesial temporal cortex, caudate, thalamus, and basomesial diencephalic structures showed sex effects with the females having greater relative volumes in these regions than the males. Overall, these results are consistent with earlier reports and describe in greater detail the regional pattern of age-related differences in gray and white matter in normally developing children and adolescents. [source] Villous trophoblast growth in pregnancy at high altitudeJOURNAL OF ANATOMY, Issue 5 2002T. M. Mayhew The trophoblastic epithelium of placental villi exhibits continuous turnover. Phases of proliferation, recruitment, maturation, terminal differentiation (apoptosis) and extrusion exist in steady state and occur in distinctive spatial compartments, viz. cytotrophoblast cells (CT), syncytiotrophoblast (ST), syncytial knots (SK), denudation sites (DEN) and syncytial fragments. Hypoxia in vitro stimulates CT proliferation but inhibits recruitment into ST. Pregnancy at high altitude (HA) is associated with reduced birthweight and provides a convenient model of preplacental (hypobaric) hypoxia. HA placentas show impoverished villous growth and changes in the incidences of CT cells and SK regions. Here we examine placentas from Amerindian and nonindigenous women who completed full-term pregnancies at low altitude (LA; 400 m; n = 25) and high altitude (HA; 3600 m; n = 45) in Bolivia. We test the hypothesis that HA pregnancy disturbs the epithelial steady state as reflected in the relative volumes and surfaces of trophoblast compartments. Masson trichrome stained tissue sections and microscopical fields were generated by uniform random sampling. Point and intersection counts were used to estimate the volumes and surface areas of nonsyncytial knots (nonSK), SK regions, syncytial bridges (SB) and denudation sites (DEN). Absolute values were compared by 2-way analyses of variance to resolve altitudinal from ethnic effects. At LA, trophoblast comprised about 85% nonSK, 8% SK, 5% SB and 3% CT by volume. Its maternal surface area comprised about 91% nonSK, 5% SK, 2% SB, and 3% DEN. Apart from CT (the fractional volume of which increased to 4%, P < 0.05), relative volumes of trophoblast compartments did not alter significantly at HA. However, there was a roughly 30% reduction in absolute volume of trophoblast at HA (P < 0.001) which could be explained mainly by a decrease in volume of nonSK regions (P < 0.001). The volume of CT was unaltered. Absolute surface areas of villi also declined at HA (by 20%, P < 0.01) and, again, this was attributed mainly to nonSK. The findings confirm that poor villous growth is partly due to failure of trophoblast to attain the growth seen at LA. The reduced trophoblastic growth occurs despite an increase in relative volume of CT cells (consistent with previously reported increases in proliferative activity) and, probably, by a combination of compromised syncytial fusion and continuing extrusion of syncytial fragments. [source] The Relationship Between Endocardial Voltage and Regional Volume in Electroanatomical Remodeled Left Atria in Patients with Atrial Fibrillation: Comparison of Three-Dimensional Computed Tomographic Images and Voltage MappingJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2009JAE HYUNG PARK B.Sc. Background: Long-standing atrial fibrillation (AF) changes left atrial (LA) morphology, and the LA size is related to recurrence after radiofrequency catheter ablation (RFCA). We hypothesize that LA morphology, based on embryological origin, affects the outcome of RFCA. Methods: We analyzed 3D computed tomographic (CT) images of LA in 70 patients with AF (54 males, 55.6 ± 10.5 years old, paroxysmal AF (PAF):persistent AF (PeAF) = 32:38) who underwent RFCA. Each LA image was divided into venous atrium (VA), anterior LA (ALA), LA appendage (LAA), and both antrum. Absolute and relative volumes were calculated, and the lengths of linear ablation sites were measured. Results: (1) In patients with the mean LA voltage , 2.0 mV, LA volume, especially ALA, was larger (P < 0.01) compared to those with LA voltage > 2.0 mV. (2) The total LA volume was significantly larger (P < 0.01) and LAA voltages (P < 0.05) and conduction velocities (P < 0.05) were lower in patients with PeAF than in those with PAF. (3) In patients with recurrence, LA volume was generally larger (P < 0.01) than in those without recurrence. In PAF patients with recurrence, the relative volume of ALA was significantly larger (P < 0.01) than those without recurrence. Conclusions Morphologically remodeled LA has low endocardial voltage, and enlargement of ALA is more significant in electroanatomically remodeled LA. The disproportional enlargement of ALA was observed more often in PAF patients with recurrence after ablation than those without recurrence. [source] Splitting the S&P 500 futuresTHE JOURNAL OF FUTURES MARKETS, Issue 12 2004Jianli Chen In this paper we investigate the consequences of the Chicago Mercantile Exchange's 1997 redesign of the S&P 500 futures contract. The focus is on two important measures of exchange efficacy: member proprietary income and outside customer volume. Floor traders did not appear to benefit in their proprietary trading from the redesign,revenue fell after the contract split and doubling of the minimum tick. On the other hand, looking at relative volumes, it appears that customer volume was relatively constant, showing little sensitivity to the increase in tick size, possibly due to an increased use of limit orders by customers, bypassing floor traders. Through this redesign the futures exchange was apparently interested in preserving customer volume in an increasingly competitive index trading environment, not enhancing member noncompetitive proprietary trading revenue. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:1147,1163, 2004 [source] Oily calcium hydroxide suspension (Osteoinductal) used as an adjunct to guided bone regeneration: an experimental study in ratsCLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2007Andreas Stavropoulos Abstract Objectives: To evaluate whether an oily calcium hydroxide suspension (OCHS) promotes bone healing when used as an adjunct to guided bone regeneration (GBR). Material and methods: Rigid, hemispherical, teflon capsules were placed with their open part facing the lateral surface of the ramus on both sides of the mandible in 10 adult Wistar rats. In each animal, one capsule was filled out with an OCHS (test) before placement, while the capsule on the other side was left empty (control). After 4 months of healing, the animals were sacrificed and histological sections containing the capsules and the neighboring soft and hard tissues were prepared. On three to four sections taken by uniformly random sampling from each specimen, the relative volumes of (1) the newly formed bone (mineralized bone and marrow), (2) the soft connective tissue, (3) the residual OCHS, and (4) the acellular (empty) space inside the capsule were estimated by a point-counting technique, and expressed as percentage of the space originally created by the capsule. Results: There was no new bone formation inside the capsules in all but one test specimen, where only a minimal amount of newly formed bone could be observed in continuation with the lateral surface of the ramus. OCHS had a homogenous appearance and occupied the major portion (79.4%) of the space created by the capsule. No signs of active resorption of the material could be observed. On the contrary, 31.5% of the space provided by the capsule was filled out with newly formed bone in the control group. The new bone had a trabecular appearance with large marrow spaces filled with hematopoietic and fatty marrow. The rest of the capsule space in the controls appeared empty. Conclusion: OCHS may hamper bone healing when used as an adjunct to GBR. [source] | |||||||||||||