bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cochlear nuclear complex of mice
Authors: Webster Douglas B. , Trune Dennis R. 
Published: February 2005

AbstractUsing serial sections stained with luxol fast blue‐cresyl violet, the cochlear nuclei of CBA/J mice were parcellated into the same cytoarchitectonic areas and layers that Osen (1969) used in cats. Within the spherical cell areas, the distribution of Nissl substance is more reliable than soma shape in identifying the spherical cells. The area of large spherical cells is extremely small in CBA/J mice but does contain significantly larger neurons than the small spherical cell area. In Golgi preparations, bushy cells are found in all areas of the ventral cochlear nucleus except in the octopus cell area and granule cell layer. They are more numerous anteriorly than posteriorly and details of their morphology are quite variable. Stellate cells are found throughout the ventral cochlear nuclei but are present in greatest numbers in the multipolar cell area; they are rare in the large spherical cell area and octopus cell area. Because size, soma morphology, and dendritic arborization vary on a continuum rather than in discrete steps, we have not subcategorized these neurons. Octopus cells are restricted to the posterior, dorsomedial area of the ventral cochlear nucleus. In the central region of the dorsal cochlear nucleus, stellate cells abound and are categorized as vertical, elongate, or radiate cells. In the granule layer of the dorsal cochlear nucleus there are both fusiform and Purkinje‐like neurons, so named because of their resemblance to cerebellar Purkinje cells. These Purkinje‐like cells differ from fusiform cells in having (1) a smaller cell body, spherical in shape, (2) no basal dendrites, (3) a sagittal dendritic orientation, (4) elaborate dendritic branching, and (5) abundant dendritic spines.
An immunocytochemical study of the cytogenesis of pancreatic endocrine cells in the lizard, Anolis carolinensis
Authors: Rhoten William B. , Hall Carl E. 
Published: February 2005

AbstractThe differentiation of the pancreatic endocrine cells in the lizard Anolis carolinensis following oviposition was examined. Immediately postoviposition (PO) there was no apparent differentiation of epithelioid cells into endocrine or exocrine components. Individual subpopulations of the endocrine‐like cells, which could not be identified during the early PO period on the basis of either their tinctorial properties at the light‐microscopic level or their granule morphologies at the electron‐microscopic level, exhibited specific hormonal localization by peroxidase‐antiperoxidase complex immunocytochemistry. All four hormones searched for, insulin, glucagon, somatostatin, and pancreatic polypeptide (PP), were present in epithelioid cells shortly after oviposition. However, the immunostained secretory granules in the early PO period were smaller than those of the adult. Secretory granule morphologies that are typical of the adult were acquired at different times during development. Delta granules were observed first and were followed by alpha granules, and beta granules which appeared shortly before birth. The secretory granules of the PP‐containing F cells could not be readily placed within this maturation sequence. Mosaic cells (containing more than one hormone) were not seen. Levels of immunoreactive insulin and glucagon in the pancreas increased several fold from day 10 to day 28 PO, but the attainment of adult beta‐granule morphologies did not appear to be directly related to insulin itself. The results show that cytodifferentiation of the anolian endocrine pancreas occurs postoviposition and that immunocytochemical methods can be used to follow an organelle sequence during development. These findings suggest that subcellular organelles undergo structural remodeling during maturation which, at least in the case of secretory granules, may have functional significance.
A cytochemical study of the Golgi apparatus of the spermatid during spermiogenesis in the rat
Authors: Tang X. M. , Lalli M. F. , Clermont Y. 
Published: February 2005

AbstractThe reactivity of the various components of the Golgi apparatus of rat spermatids for three phosphatase activities (nicotinamide adenine dinucleotide phosphatase, NADPase; thiamine pyrophosphatase, TPPase; cytidine monophosphatase, CMPase) and the incorporation of 3H‐fucose by the spermatids was analyzed at the 19 steps of spermiogenesis, i.e., during and after this organelle elaborated the glycoprotein‐rich acrosomic system. During steps 1–3, the Golgi apparatus produced, in addition to the proacrosomic granules, multivesicular bodies that became associated with the chromatoid body. NADPase was located within the four or five intermediate saccules of Golgi stacks, and TPPase was found in the last one or two saccules on the trans aspect of the stacks from steps 1 to 17 of spermiogenesis. CMPase was located within the thick saccular GERL elements found in the trans region of the Golgi apparatus from steps 1 to 7 of spermiogenesis, but the CMPase‐positive GERL disappeared from the Golgi apparatus after its detachment from the acrosomic system at step 8. The acrosomic system itself was reactive for CMPase and TPPase but was negative for NADPase, while the multivesicular bodies were CMPase and NADPase positive but unreactive for TPPase. Tritiated‐fucose was readily incorporated within the Golgi apparatus of steps 1–17 spermatids; in steps 1–7 it was subsequently incorporated within the acrosomic system and multivesicular bodies. These various data indicated (1) that the Golgi apparatus of spermatids, although it loses its CMPase‐positive GERL element in step 8, retains evidence of functional capacity until it degenerates in step 17; (2) that in early spermatids the various saccular components of the Golgi are specialized with respect to enzymatic activities; and (3) that each Golgi region may contribute in a coordinated fashion to the formation of the acrosomic system and multivesicular bodies.
Morphologic changes in the lung during the lifespan of Fischer 344 rats
Authors: Pinkerton Kent E. , Barry Brenda E. , O'Neil John J. , Raub James A. , Pratt Philip C. , Crapo James D. 
Published: February 2005

AbstractPulmonary structure and function were quantitatively investigated over the lifespan of the Fischer 344 rat by morphometric and physiologic techniques. Male animals 1 week, 6 weeks, 5 months, 14 months, and 26 months of age and female animals 5 months, 14 months, and 26 months of age were studied. All alveolar tissue compartments demonstrated significant increases in volume, surface area, and cell number during the first 5 months of life. From 5 to 26 months of age, remodelling in the epithelial and interstitial compartments continued to take place while the endothelial compartment remained relatively unchanged. In the epithelial compartment the ratio of type II cells to type I cells lining the alveolar surface decreased as age increased. In the interstitial compartment the volume of the noncellular components of the interstitium increased by 39% in males and by 89% in females from 5 to 26 months of age. Physiologic measurements of lung volumes in males at 6 weeks, 14 months, and 26 months demonstrated progressive increases in vital capacity (VC) and total lung capacity (TLC). Morphometric pulmonary‐diffusion capacity (DLO2) increased in males from 1 week to 5 months of age and remained relatively unchanged from 5 to 26 months of age in both sexes.
Overall architecture and pattern of lymph flow in the rat lymph node
Authors: Sainte‐Marie G. , Peng F.‐S. , Bélisle C. 
Published: February 2005

AbstractThe immunogenic content of the afferent lymph stimulates structures in the lymph node. Thus, a better knowledge of the processes of lymph flow and filtration in the organ should help us better understand various aspects of the node's function. To gain this understanding, we analyzed the distribution of flow in rat node draining areas locally injected with a small dose of China ink. Because the lymph‐flow pattern is likely related to the overall architecture of the node, we simultaneously studied its morphology. Indeed, while the different structures of the node are known, some aspects of its overall architecture need to be resolved. The present work aimed to accomplish this by an analysis of semiserial sections of nodes from various anatomical locations in normal rats; the sections were stained by the Dominici technique or silver‐impregnated.With respect to their architecture, the nodes could be distinguished into those with either a discontinuous or a continuous subcapsular sinus and peripheral cortex. These are referred to here, respectively, as segmented and nonsegmented nodes. In the segmented nodes, the subcapsular sinus with the peripheral cortex is separated by “gaps,” in which medullary sinuses reached the capsule. Further, a node appears to be divided into one or more “physiological compartments,” each one representing a nodal area related to an opening of an afferent lymphatic.The findings on China‐ink distribution indicate that the lymph‐flow pattern varies in different nodes and is determined by the particular architecture of a node, i.e., the lymph flow in a given node aligns itself along the pattern of segmentation of the organ. The findings suggest that the lymph content is first held by the endothelium lining the inner wall of a restricted area of the subcapsular sinus in a concentration which decreases with the distance from the related afferent lymphatic opening. Part of the content, possibly its nonimmunogenic fraction, would later be released to flow further along the sinus. It would then be phagocytosed by the macrophage accumulation located in the portions of medullary sinuses into which the lymph enters from the subcapsular sinus. The lymph thus filtered then flows along the medullary sinuses and leaves the organ. The latter findings also indicate that a node is divided into physiological compartments, each one being stimulated by the lymph from a given afferent lymphatic opening. As the immunogenic content of the lymph can differ from one lymphatic to another, this explains the frequent variations in similar structures located in different areas of a given node. Hence, the pattern of distribution of the openings of the afferent lymphatics of a node can account for the particularities of its overall architecture and its division into physiological compartments.
Immunocytochemical localization of corticotropin‐releasing factor (CRF) in the rat brain
Authors: Merchenthaler I. , Vigh S. , Petrusz P. , Schally A. V. 
Published: February 2005

AbstractThe immunocytochemical localization of neurons containing the 41 amino acid peptide corticotropin‐releasing factor (CRF) in the rat brain is described. The detection of CRF‐like immunoreactivity in neurons was facilitated by colchicine pretreatment of the rats and by silver intensification of the diaminobenzidine end‐product. The presence of immunoreactive CRF in perikarya, neuronal processes, and terminals in all major subdivisions of the rat brain is demonstrated. Aggregates of CRF‐immunoreactive perikarya are found in the paraventricular, supraoptic, medial and periventricular preoptic, and premammillary nuclei of the hypothalamus, the bed nuclei of the stria terminalis and of the anterior commissure, the medial septal nucleus, the nucleus accumbens, the central amygdaloid nucleus, the olfactory bulb, the locus ceruleus, the parabrachial nucleus, the superior and inferior colliculus, and the medial vestibular nucleus. A few scattered perikarya with CRF‐like immunoreactivity are present along the paraventriculo‐infundibular pathway, in the anterior hypothalamus, the cerebral cortex, the hippocampus, and the periaqueductal gray of the mesencephalon and pons. Processes with CRF‐like immunoreactivity are present in all of the above areas as well as in the cerebellum. The densest accumulation of CRF‐immunoreactive terminals is seen in the external zone of the median eminence, with some immunoreactive CRF also present in the internal zone. The widespread but selective distribution of neurons containing CRF‐like immunoreactivity supports the neuroendocrine role of this peptide and suggests that CRF, similarly to other neuropeptides, may also function as a neuromodulator throughout the brain.
Development of the connective tissue network in the neonatal hamster heart
Authors: Borg Thomas K. 
Published: February 2005

AbstractThe formation of the connective tissue network, composed principally of collagen, in the left ventricle of the neonatal hamster heart developed primarily during the first 20 days postpartum. The weave network of the endomysium, which was absent at birth, was visible by 4 days and was similar to that of the adult by 15 days postpartum. Myocyte‐myocyte and myocyte‐capillary struts formed gradually as the heart underwent physiological hypertrophy. These data were similar to the development of the connective tissue network in the rat except that the myocyte‐myocyte struts were more numerous in the hamster. Presumably this is because the hamster has a higher heart rate, which would require more mechanical coupling of the myocytes. Formation of the struts appears to take place at precise areas on the sarcolemma through the interaction of collagenous and noncollagenous components of the extracellular matrix.
Implantation in the rhesus monkey: Initial penetration of endometrium
Authors: Enders Allen C. , Hendrickx Andrew G. , Schlafke Sandra 
Published: February 2005

AbstractA series of peri‐implantation stages of the rhesus monkey has been collected; these range from preimplantation blastocysts through initial implantation to early villus formation. The three earliest postimplantation specimens encompass the stages of penetration into and through the uterine luminal epithelium and into endometrial blood vessels. The day of pregnancy was established by radioimmunoassay of estrogen (E) levels to determine the prevulatory E peak, and in each instance the embryo was examined to determine the extent of development. The conceptus collected on day 9.5 of pregnancy was the earliest implantation stage; it ballooned above a depression in the endometrium to which it was firmly attached. A column of syncytial trophoblast penetrated into the uterine epithelium to the basal lamina of the latter. The syncytial trophoblast shared junctional complexes with the uterine epithelial cells to which it was apposed at the margin of the site of epithelial penetration. Basal to the apical junction complexes, processes of syncytium indented uterine epithelial cells. Several epithelial cells had been partially isolated and surrounded by flanges of syncytial trophoblast. In the next specimen, at 10.0 days after ovulation, the uterine epithelium had initiated the epithelial plaque reaction. The trophoblast had extended along the residual basal lamina of the uterine epithelium and into the neck of an adjacent uterine gland. Cytotrophoblast was abundant in the central region of the implantation site, and was intermixed with syncytium which formed the majority of the peripheral trophoblast. In several places clefts had formed in the syncytial trophoblast; these clefts were lined with microvilli, had intermicrovillous caveolae, and consequently more closely resemble the trophoblast that eventually lines the intervillous spaces than the trophoblast involved in initial invasion. In the day‐10.5 specimen, in addition to prelacunar clefts, lacunae containing maternal blood were present for the first time. The basal lamina was penetrated in many places, and syncytial trophoblast was interposed between maternal endothelial cells of the underlying vessels.It was concluded that syncytial trophoblast is the first tissue to penetrate the uterine luminal epithelium; that the basal lamina of the uterine luminal epithelium, but not the basal lamina of endothelium, constitutes a temporary barrier to trophoblast penetration; that invasion is accomplished with less destruction of maternal tissue than previously suggested; and that the rapid superficial growth of the placenta is made possible by the early tapping of the endometrial vessels.
The early development of the AV node and bundle in the ferret heart
Authors: Marino Thomas A. , Severdia Joseph 
Published: February 2005

AbstractThe development of the atrioventricular (AV) junctional tissues in the ferret embryonic heart was studied on days 16, 18, and 21 of gestation. This important region of the heart was examined with PAS and toluidine‐blue staining at the light microscope level and with transmission electron microscopy at the ultrastructural level. By day 16 of gestation the ferret heart was in the initial stages of convolution. The heart was at the primitive four‐chamber stage by 18 days postcoitum. On day 21 of gestation the heart was in the process of being septated. The AV nodal primordia were first observed as two clusters of cells in the dorsal wall of the common atrium of the 16 day ferret embryo heart. These nodal primordial cells were morphologically different from working myocardial cells or cells of the AV canal. The AV canal cells were particularly numerous in the dorsal wall of the canal and eventually gave rise to the AV bundle in this region. On day 18 of gestation the morphological differences between the AV nodal, AV canal, and myocardial cells were readily apparent. By 21 days postcoitum, the AV node with its two regions had reached its definitive anatomic position. The AV bundle was also present in its normal adult location. The AV nodal cells were distinctly different when compared to the ventricular or atrial myocytes at this stage in development. In addition, the AV bundle cells were morphologically different from the AV nodal cells and working myocardial cells. A discussion of these findings relates this information to current descriptions of how the AV node and bundle develop.
A morphometric analysis of craniofacial growth and changes in spatial relations during secondary palatal development in human embryos and fetuses
Authors: Diewert Virginia M. 
Published: February 2005

AbstractStaged human embryos and fetuses in the Carnegie Embryological Collection were morphometrically analyzed to show craniofacial dimensions and changes in spatial relations, and to identify patterns that would reflect normal developmental events during palatal formation. Normal embryos aged 7–8 weeks postconception (Streeter‐O'Rahilly stages 19–23) and fetuses aged 9–10 weeks postconception, in eight groups with mean crownrump (CR) lengths of 18–49 mm, were studied with cephalometric methods developed for histologic sections. In the 4‐week period studied, facial dimensions increased predominantly in the sagittal plane with extensive changes in length (depth) and height, but limited changes in width. Growth of the mandible was more rapid than the nasomaxillary complex, and the length of Meckel's cartilage exceeded the length of the oronasal cavity at the time of horizontal movement of the shelves during stage 23. Simultaneously with shelf elevation, the upper craniofacial complex lifted, and the tongue and Meckel's cartilage extended forward beneath the primary palate. Analysis of spatial relations in the oronasal cavity showed that the palatomaxillary processes became separated from the tongue‐mandibular complex as the head extended, and the tongue became positioned forward with growth of Meckel's cartilage. As the head position extended by 35°, the cranial base angulation was unchanged and the primary palate maintained a 90° position to the posterior cranial base. However, the sagittal position of the maxilla relative to the anterior cranial base increased by 20° between stages 19 and 23. In the late embryonic and early fetal periods, the mean cranial 128° and the mean maxillary position angulation of approximately 34° were similar to the angulations previously shown to be present later prenatally and postnatally. The results suggest that human patterns of cranial base angulation and maxillary position to the cranial base develop during the late embryonic period when the chondrocranium and Meckel's cartilage form the primary skeleton.
Effects of pinealectomy on reproduction in the Syrian hamster mutant anophthalmic white (Wh)
Authors: Hagen Susan C. , Asher James H. 
Published: February 2005

AbstractThe gene Wh, causing anophthalmia in the Syrian hamster, Mesocricetus auratus, is a pleiotropic gene affecting eye development, pigmentation, hearing, and reproduction. Male hamsters homozygous for this gene are usually sterile. Since both Wh and the pineal organ are known to suppress reproductive function, the objective of this study was twofold: (1) to determine whether Wh, by itself, influences testicular differentiation; and (2) to determine whether removal of the pineal gland will restore fertility to both experimentally blinded (B), genetically normal [wh/wh(B)] hamsters and mutant, eyeless (Wh/Wh) hamsters. Accordingly, one testis from each of ten wh/wh(B) and ten Wh/Wh hamsters at approximately 60 days of age was removed, and these testes were compared at the gross and light microscopic level. Since all testes were identical at 60 days of age and contained normal differentiating germ cells, the gene Wh does not appear to affect initial testicular differentiation. Testicular tissues from at least ten wh/wh, wh/wh(B), heterozygous (Wh/wh), and Wh/Wh(B) hamsters, at 135 days of age, were also compared. Testes from all wh/wh(B), and 70% of the Wh/Wh hamsters were hypoplasic and aspermic. Approximately 30% of the testes from Wh/Wh hamsters contained some seminiferous tubules with normal sperm present. Pinealectomy fully restored adult testicular size and morphology in all wh/wh(B) and Wh/Wh hamsters. Thus, it was demonstrated that the atrophy of testes from Wh/Wh individuals is a pineal‐mediated phenomenon due to failure of eye development and the subsequent lack of a functional visual pathway. Testes from Wh/Wh hamsters appear to be completely competent to respond to the normal, antigonadotrophic effects of the pineal.
Characterization of putative secretory sites on ameloblasts of the rat incisor
Authors: Nanci A. , Warshawsky H. 
Published: February 2005

AbstractThe distribution and structure of the putative sites where enamel matrix is secreted from the ameloblast were studied by correlating the external topography with the distribution of organelles in Tomes' process cut in various planes of section. Both the interrod and rod secretion sites are associated with deep membrane infoldings. It was found that the interrod secretion site completely surrounds each ameloblast, and the marked interdigitation of adjacent cells results in a cooperative growth front for interrod enamel. In contrast, the rod secretion site is present on only one surface of the interdigitating portion of Tomes' process. Numerous granules were observed adjacent to the membrane infoldings associated with both sites, and granules were seen fused to membrane infoldings suggesting that the matrix of enamel is a merocrine secretion product.