bluuebunny/crossref_metadata_2025_split huggingface dataset:
Brain growth and differentiation in two fetal bats: Qualitative and quantitative aspects
Authors: Pirlot Paul , Bernier Réjane 
Published: February 2005

AbstractThe development of the main brain components in two fetal bats (one insectivorous and one frugivorous type) is studied quantitatively and comparatively. The telencephalon, cerebellum, and diencephalon grow faster in the frugivorous bat. The brainstem maintains a greater relative volume throughout in the insectivorous type. The morphology and density of neurons in the cerebellum, cAUdate nucleus, olfactory, mitral stratum, and neocortical layer II suggest that there exists an initial delay in development in the frugivorous bat; through subsequent reordering, however, it becomes more advanced in development in accordance with the more progressive status of the adult forms in its category. In this there may be a certain ontogenetic recapitulation of a possible chiroptera phylogeny. These comparisons also point to the precociousness of the functional determination of those structures that are related to future behavior in a purely deterministic, non‐teleological sense. The qualitative differentiation appears to be more significant than might be expected in comparison with the quantitative proliferation. Technical problems in volved in the study of brain morphogenesis are discussed, especially the difficulty of distinguishing the respective effects of cell multiplication, cell death, and artificial increase in cell density through tissue shrinkage.
Pathogenesis of bromodeoxyuridine‐induced cleft palate in hamster
Authors: Shah Ravindra M. , King Katherine O. , Feeley E. J. Elizabeth 
Published: February 2005

AbstractIn the present study, the morphological, histochemical, biochemical, and cellular aspects of the pathogenesis of bromodeoxyuridine (BrdU)‐induced cleft palate in hamster fetuses were analyzed. Morphological observations indicated that BrdU interferes with the growth of the vertical shelves and thus induces cleft palate. At an ultrastructural level, BrdU‐induced changes were first seen in the mesenchymal cells. Eighteen hours after drug administration, the initial alterations were characterized by swelling of the nuclear membrane and the appearance of lysosomes in the mesenchymal cells of the roof of the oronasal cavity. During the next 6 hr, as the palatal primordia developed, lysosomes were also seen in the overlying epithelial cells. The appearance of lysosomal activity, which was verified by acid phosphatase histochemistry, was temporally abnormal and was interpreted as a sublethal response to BrdU treatment. Later the cellular alterations subsided; 48 hr after BrdU treatment, they were absent in both the epithelial and mesenchymal cells of the vertically developing palatal shelves. Subsequently, unlike controls (in which the palatal shelves undergo reorientation and fusion), the BrdU‐treated shelves remained vertical until term. Biochemical determination of DNA synthesis indicated that although there was an inhibition of DNA synthesis at the time of appearance of palatal primordia, a catch‐up growth during the ensuing 12 hr may have restored the number of cells available for the formation of a vertical palatal shelf. It was suggested that BrdU affected cytodifferentiation in the palatal tissues during the critical phase of early vertical development to induce a cleft palate.
Size and shape of human cranial sutures–A new scoring method
Authors: Hauser Gertrud , Manzi Giorgio , Vienna Alessandro , de Stefano Gian Franco 
Published: February 2005

AbstractA method for the differentiation of sutural patterns of the human cranial vault is introduced. Three criteria of differentiation are considered, one for size and two for shape: (1) maximal shape extension; (2) basic configuration; (3) secondary protrusion. The method is illustrated here for the coronal and lambdoid sutures of 70 recent Italian skulls (35 adult males and 35 adult females). Differences between coronal and lambdoid sutural size and shape can be detected analytically; for example, the coronal suture commonly shows lesser degrees of shape extension, a simpler basic configuration, and an absence of secondary protrusion. Heterogeneity within each suture, as well as a relationship among corresponding sections and between the three criteria adopted, have been also observed; symmetry predominates for both the sutures, and sexual differences are slight.
Morphometric study of the prepubertal rabbit testis: Germ cell numbers and seminiferous tubule dimensions
Authors: Iczkowski Kenneth A. , Sun Eric L. , Gondos Bernard 
Published: February 2005

AbstractTestes from rabbits aged 1–9 weeks were examined by light microscopy. Changes in seminiferous tubule dimensions, testicular volume, and volume fraction of tubules were assessed. Germ cells and Sertoli cells were counted in round tubular cross sections and total germ cell number in each testis was estimated. Mitotic, meiotic, and degenerative activities of germ cells as well as their basal or central positions within tubules were quantified. A marked, steady increase in testis volume and in tubular length and volume occurred over the prepubertal period; but diameter underwent no significant increase and in fact decreased until week 4. Overall, tubules lengthened 40‐fold and testis volume increased 25‐fold; the percentage volume of the testis occupied by tubules rose from one‐third neonatally to three‐fifths at the onset of spermatogenesis. The ratio of germ cells to total tubular (germ and Sertoli) cells was lowest at 3 weeks. However, the total number of germ cells increased little until 3 weeks, after which it rose at a sharp rate commensurate with testis volume. Percentage of germ cells in mitosis peaked sharply at 3 weeks, dropped in subsequent weeks, and then rose at 7 weeks at the initiation of spermatogenesis. Importantly, the surge in mitosis at 3 weeks was followed by a redistribution of germ cells to a predominantly basal location from 3 to 7 weeks. Meiotic activity was sparse at 7 weeks and became abundant by 9 weeks. Germ cell degeneration remained relatively constant during weeks 1 through 6, with an increase at 7 weeks.
Distribution of cytochrome P‐450 monoxygenase enzymes in the nasal mucosa of hamster and rat
Authors: Adams Donald R. , Jones Alisa M. , Plopper Charles G. , Serabjit‐Singh Cosette J. , Philpot Richard M. 
Published: February 2005

AbstractDeposition of inhaled particulates onto the respiratory mucosa is relatively great in that portion of the nasal cavity unprotected by ciliated, goblet, or keratinized superficial cells. The cytochrome P‐450 system is an important enzyme system involved in the biotransformation of xenobiotics into metabolites that are more readily absorbed. To examine the transitional region caudal to the nasal vestibule, nasal tissues of hamster and rat were prepared for immunocytochemistry. Blocks of tissue representing four levels along the axis of the nasal cavity were examined. Paraffin sections were processed through the avidin‐biotin peroxidase procedure, with diaminobenzidine tetrahydrochloride as the chromagen. Enzyme localization was accomplished through the use of antibodies for three rabbit cytochrome P‐450 isozymes; 2, 5, and 6 (subfamilies IIB, IVB, and IA, respectively); and for rabbit NADPH‐cytochrome P‐450 reductase. Enzyme distribution was similar in both hamster and rat nasal tissues except in cells of striated and intercalated ducts of nasal glands and in cells of the nasolacrimal duct where immunoreactivity for reductase and isozyme 2 was intense in nonciliated cells lining the nonolfactory epithelium, in sustentacular cells of the olfactory epithelium, and acinar cells of olfactory glands. Distribution of reaction products to isozyme 5 and 6 were similar to but not so intense as those of reductase an isozyme 2. Reaction products for reductase and isozyme 2 occurred generally in the same cellular and intracellular regions with the following exceptions: isozyme 2 was more concentrated in cells of striated ducts and of the nasolacrimal duct, and reductase was more abundant in intercalated ducts of nasal glands. Ciliated and goblet cells in epithelia lining much of the nasal cavity evidenced little reactivity; those ciliated cells adjacent to olfactory mucosa contained reaction product. It is concluded that the nonciliated epithelium adjacent to the internal ostium of the nose contains enzymes essential for biotransforming extrinsic particles that impinge on it from inhaled air currents.
Spontaneous decidual reactions and menstruation in the black mastiff bat, Molossus ater
Authors: Rasweiler John J. 
Published: February 2005

AbstractUterine function was assessed histologically in nonpregnant Molossus ater removed from a laboratory breeding colony. During the luteal phase of the cycle, bilateral decidual reactions were found to develop spontaneously in the absence of either embryos or experimental manipulation of the uterus. These included the formation of early decidual giant cells, closure of the uterine lumina, and morphological changes in the endometrial blood vessels. Some endothelial cell hypertrophy was noted in much of the decidua, but this was most pronounced in vessels associated with an unusual vascular tuft that formed in the endometrium surrounding the cranial end of the uterine lumen. These latter vessels also developed very prominent basal laminae. In pregnant bats, this tuft played a central role in the morphogenesis of the definitive discoidal chorioallantoic placenta. At the end of nonpregnant cycles, the decidua became necrotic and was sloughed off with associated bleeding. As in menstruating catarrhine primates, the endometrium of M. ater is vascularized by spiral arterioles and populated by distincitve granulocytes containing large, acidophilic granules. Increased coiling of these arterioles did not appear to be an essential element in the mechanism of menstruation in this species. M. ater is a monotocous, seasonal breeder, with a relatively long gestation period. Although it has a bicornuate uterus, ovulation and implantation appear to occur only on the right side of the tract. The ability to menstruate probably affords this bat an efficient mechanism for eliminating a highly differentiated endometrium from the usual implantation site in the event of a reproductive failure. In the wild, this may provide M. ater with another chance to establish a pregnancy at a still opportune time during the same breeding season.
Development of Sertoli cell junctional specializations and the distribution of the tight‐junction‐associated protein ZO‐1 in the mouse testis
Authors: Byers Stephen , Graham Robert , Dai Hai Ning , Hoxter Becky 
Published: February 2005

AbstractBasally located tight junctions between Sertoli cells in the postpubertal testis are the largest and most complex junctional complexes known. They form at puberty and are thought to be the major structural component of the “blood–testis” barrier. We have now examined the development of these structures in the immature mouse testis in conjunction with immunolocalization of the tight‐junction‐associated proteins ZO‐1 (zonula occludens 1). In testes from 5‐day‐old mice, tight junctional complexes are absent and ZO‐1 is distributed generally over the apicolateral, but not basal, Sertoli cell membrane. As cytoskeletal and reticular elements characteristic of the mature junction are recruited to the developing junctions, between 7 and 14 days. ZO‐1 becomes progressively restricted to tight junctional regions. Immunogold labeling of ZO‐1 on Sertoli cell plasma membrane preparations revealed specific localization to the cytoplasmic surface of tight junctional regions. In the mature animal, ZO‐1 is similarly associated with tight junctional complexes in the basal aspects of the epithelium. In addition, it is also localized to Sertoli cell ectoplasmic specializations adjacent to early elongating, but not late, spermatids just prior to sperm release. Although these structures are not tight junctions, they do have a similar cytoskeletal arrangement, suggesting that ZO‐1 interacts with the submembrane cytoskeleton. These results show that, in the immature mouse testis, ZO‐1 is present on the Sertoli cell plasma membrane in the absence of recognizable tight junctions. In the presence of tight junctions however, ZO‐1 is found only at the sites of junctional specializations associated with tight junctions and with elongating spermatids.
Proximal skeletal muscle alterations in streptozotocin‐diabetic rats: A histochemical and morphometric analysis
Authors: Medina‐Sanchez Maria , Rodriguez‐Sanchez Carmen , Vega‐Alvarez Jose Antonio , Menendez‐Pelaez Armando , Perez‐Casas Antonio 
Published: February 2005

AbstractThe response of rat quadriceps muscle fibers to chronic streptozotocin (STZ) diabetes was studied. Transverse sections of rectus femoris muscle from diabetic and weight‐matched control rats were assayed for myofibrilar adenosine triphophatase (ATPase) and nicotinamide adenine dinucleotide‐tetrazolium reductase (NADH‐TR). A quantitative analysis was carried out by an automatic interactive analysis system focused on the fiber type size and distribution. STZ‐induced diabetes caused important effects in this muscle, with changes in the distribution of oxidative enzyme reactions, type I fiber hypertrophy, and type II fiber atrophy, which was greater in type IIB than in type IIA. It is concluded that hypoinsulinism produces morphological alterations in proximal skeletal muscle fibers that are similar to those of neurogenic myopathy. Thus the pathological changes in these mammalian muscle fibers could explain the clinical syndrome seen in diabetic patients called “diabetic symmetrical proximal motor neuropathy”, perhaps the least understood of the major neuropathic complications of diabetes.
Effects of early partial decapitation on the ontogenic development of chicken lymphoid organs. I. Thymus
Authors: Herradón P. G. , Razquin B. , Zapata A. G. 
Published: February 2005

AbstractFor the present study we used the classic model of early partial decapitation (DCx) of chicken embryos (Fugo, J. Exp. Zool., 85:271–298, 1940; Betz, Gen. Comp. Endocrinol., 9:172–186, 1967) in an attempt to analyze the neuroendocrine immune relationships during ontogeny. The elimination of the prosencephalon in chickens at 33–38 hr of incubation induced profound structural, histochemical, and morphometric changes in the embryonic development of the thymus gland. These included a greater development of the cortex than of the medulla, an increased mitotic index, high numbers of pyknotic cells, and enlarged connective tissue trabeculae containing numerous large lymophoid cells; hypertrophied reticular‐epithelial cells; delayed appearance of medullary epithelial cysts; and intrathymic granulopoiesis. Furthermore, preliminary radioimmunoassays revealed a sharp increase in the values of circulating thymic hormones, mainly thymosin β4 in 17‐day‐old embryos. The results are discussed with regard to the possible role of prolactin, thyroxine, testosterone, and thymic hormones in the ontogenic development of the chicken thymus.
Interodontoblastic collagen (von Korff fibers) and circumpulpal dentin formation: An Ultrathin serial section study in the cat
Authors: Bishop M. A. , Malhotra M. , Yoshida S. 
Published: February 2005

AbstractThe collagenous fibers of von Korff pass from the dentin matrix between the odontoblasts into the dental pulp. Although collagen fibrils are known to be present between odontoblasts, the existence of von Korff fibers has remained controversial. This may be because their continuity between the dentin matrix and the pulp has not been demonstrated ultrastructurally.In this study we have examined the odontoblast layer in the middle to apical regions of perfusionfixed permanent canine teeth of cats by using transmission electron microscopy. Ultrathin sections of demineralized specimens revealed frequent bundles of collagen fibrils (1) entering the odontoblast layer from the predentin, (2) present between odontoblst cell bodies, and (3) passing form between the odontoblasts into the pulp.The question of continuity of these bundles from the predentin, across the odontoblast layer into the pulp was examined in ultrathin serial sections. Unbroken continuity of a collagen bundle from the predentin between the odontoblasts into the pulp was established in a reconstruction of one series of 22 serial sections and was very strongly suggested by a number of other series in which the numbers of available sections restricted their full visibility.This investigation has shown, therefore, that classical von Korff fibers are present and that these fibers are present in fully erupted teeth with closed apices, i.e., at a time when secondary circumpulpal dentinogenesis is in progress.The findings call for a reexamination of the question of von Korff fibers during mantle dentinogenesis and primary circumpulpal dentinogenesis. Resolution of their existence at the earlier stages of dentinogenesis should be possible by using the ultrathin serial‐sectioning technique.
Tandem Scanning Confocal Microscopy (TSCM) of normal and ischemic living kidneys
Authors: Andrews Peter M. , Petroll W. Matthew , Cavanagh H. Dwight , Jester James V. 
Published: February 2005

AbstractTandem Scanning Confocal Microscopy (TSCM) allows one to section optically into and record real‐time images of living organs and tissues in a noninvasive fashion. In this paper, we will present some initial TSCM observations of subcapsular nephrons in the living, intact kidneys of Munich‐Wistar rats and evaluate the nephron's responses to temporary ischemia and to intravenous infusion of mannitol. The rats were anesthetized with Inactin and a laparotomy performed to expose the kidneys. Using a TSCM equipped with a 20× water‐immersion objective, we optically sectioned through the intact kidney capsule and recorded real‐time images of living subcapsular glomeruli and uriniferous tubules. The proximal tubule brush border was highly reflective and allowed us to distinguish between the first and second segments of the proximal tubules as well as the distal tubules. Cellular elements of the blood could be seen passing repidly through peritubular capillaries and individual glomerular capillary loops. With fluorescent filters in place, intravenously injected carboxyfluorescein was seen to pass through the glomerular capillary loops and then progressively through the different segments of the uriniferous tubules. Ligation of the renal artery resulted in rapid swelling of proximal tubule cells into the tubular lumens, loss of reflectiveness of the microvillous brush broders, and closure of the peritubular capillary spaces. Upon relases of the ligature, the proximal tubule lumens again became patent, often opening up abruptly and in a zipper‐like fashion down the length of the tubules. Increasing the glomerular filtration rate by intravenous infusion of mannitol resulted in increases in tubular luminal and perimeter dimensions. Mannitol also acted as an effective impermeant osmotic agent and prevented most of the cellular swelling which was otherwise seen in response to renal ischemia.
Liver units in three dimensions: I. organization of argyrophilic connective tissue skeleton in porcine Liver with particular reference to the “compound hepatic lobule”
Authors: Ekataksin Wichai , Wake Kenjiro 
Published: February 2005

AbstractLiver units were investigated in pig livers by means of histologic serial tracing, physical model building, and computer‐aided three‐dimensional imaging. Observations of the argyrophilic connective tissue skeleton were based mainly on the celloidin‐embedded serial sections treated with silver impregnation. The parenchymal mass that clothed the initial segments of hepatic venous radicles was demarcated by fibrous septa which formed isolable units with two basic patterns: the simple hepatic lobule (SHL) and the compound hepatic lobule (CHL). Both lobule types presented regular limiting structures circumscribing each unit. Three‐dimensional studies revealed that 25% of the lobules in a section belonged to the SHL type and 75% to the CHL type, the latter being predominant among the surface lobules. When considered in only two dimensions, however, the SHL‐like lobules constituted the majority. Polygonal analysis disclosed that the pentagonal lobule was the most typical, instead of the “hexagonal” or “classic” lobule. The CHLs represented a multiaxial unit containing a system of venous tributaries in accordance with intralobular septation, whereas the SHLs were found with one axial vessel having a dendritic tendency at the incipient end; some SHLs were drained eccentrically by separate vessels into a sublobular vein. It was observed that, in dividing CHLs, whereas particular sinosoids were transformed into portal twigs, other sinusoids were changed into central venous tributaries. Fibrous deposition occurred along the septal‐line sinusoids, bringing into view the septum‐initiating plane. Fibroconnective tissue was supplied from the portal area and central (sublobular) adventitia, where portal triad structures and adventitial arterioles, respectively, were included. The findings of the present study facilitate the understanding of several characters of the lobules that have been reported previously, or occasionally postulated, such as the portal‐central bridging tendency, the intralobular arterioles or ductules, the translobular artery or portal vein, the “portal‐portal” or “portal‐central” anastomoses, and the apposition of pericentral zone close to periportal zone. Based on differences in argyrophilia of sinusoidal reticulum, in proportion of lobule types, and in vasculature, the anatomic heterogeneity of liver unity was demonstrable in zonality, regionality, and locality. © 1991 WILEY‐LISS, INC.
Distribution of five peptides, three general neuroendocrine markers, and two synaptic‐vesicle‐associated proteins in the spinal cord and dorsal root ganglia of the adult and newborn dog: An immunocytochemical study
Authors: Bonfanti Luca , Bellardi Sergio , Ghidella Silvana , Gobetto Armando , Polak Julia M. , Merighi Adalberto 
Published: February 2005

AbstractThis study describes the immunocytochemical distribution of five neuropeptides (calcitonin gene‐related peptide [CGRP], enkephalin, galanin, somatostatin, and substance P), three neuronal markers (neurofilament triplet proteins, neuron‐specific enolase [NSE], and protein gene product 9.5), and two synaptic‐vesicle‐associated proteins (synapsin I and synaptophysin) in the spinal cord and dorsal root ganglia of adult and newborn dogs. CGRP and substance P were the only peptides detectable at birth in the spinal cord; they were present within a small number of immunoreactive fibers concentrated in laminae I–II. CGRP immunoreactivity was also observed in motoneurons and in dorsal root ganglion cells. In adult animals, all peptides under study were localized to varicose fibers forming rich plexuses within laminae I–III and, to a lesser extent, lamina X and the intermediolateral cell columns. Some dorsal root ganglion neurons were CGRP‐ and/or substance P‐immunoreactive.The other antigens were present in the spinal cord and dorsal root ganglia of both adult and newborn animals, with the exception of NSE, which, at birth, was not detectable in spinal cord neurons. Moreover, synapsin I/synaptophysin immunoreactivity, at birth, was restricted to laminae I–II, while in adult dogs, immunostaining was observed in terminal‐like elements throughout the spinal neuropil.These results suggest that in the dog spinal cord and dorsal root ganglia, peptide‐containing pathways complete their development during postnatal life, together with the full expression of NSE and synapsin I/synaptophysin immunoreactivities. In adulthood, peptide distribution is similar to that described in other mammals, although a relative absence of immunoreactive cell bodies was observed in the spinal cord.