bluuebunny/crossref_metadata_2025_split huggingface dataset:
A morphological and histochemical study of sertoli cells in normal and XX sex‐reversed mice
Authors: Chung Kyung Won 
Published: February 2005

AbstractMorphological and histochemical studies on the testes of mice with XX sex‐reversal demonstrates several profound differences in the ultracytology and oxidative enzyme activity of Sertoli cells as compared to the normal. Membranous structures, cytoplasmic inclusions, and certain dehydrogenases in Sertoli cells of normal mice are described in relation to a possible role in steroid synthesis. In XX sex‐reversed mice, two types of Sertoli cells are observed in the seminiferous tubules which are devoid of germ cells. One type is the randomly dispersed cells, which reveal the following ultrastructural alterations when compared with the normal cells: large spherical nuclei with prominent nucleoli, reduced smooth endoplasmic reticulum, pleomorphic mitochondria with no apparent cristae, and decreased lipid droplets. The other type is clustered cells which appear similar to immature Sertoli cells. These cells have small nuclei with poorly developed nucleoli, small profiles of rough endoplasmic reticulum, pleomorphic mitochondria, decreased lipid droplets, and an absence of specialized inter‐Sertoli cell junctions.The results of this study suggest that functional and ultrastructural alterations of Sertoli cells in XX sex‐reversed mice may result from degeneration or absence of germinal cells, and that steroidogenesis by Sertoli cells in mice may be associated with the development of germinal cells. It is also suggested that Sertoli cells may secrete a steroid which controls follicle‐stimulating hormone secretion.
Distribution of lumbar afferent axons in muscle coat of cat urinary bladder
Authors: Uemura Etsuro , Fletcher Thomas F. , Bradley William E. 
Published: February 2005

AbstractLumbar spinal ganglia, L2,3,4 were ablated in four cats to determine the distribution of degenerating lumbar afferents in the urinary bladder. Bladders were collected at 7, 14, 21 and 35 days following ganglionectomy. Six regions of the urinary bladder were sampled bilaterally and examined ultrastructurally in each cat. Overall, 3,033 terminal axons were counted, of which 2.6% were degenerating; of these, 9% had synaptic vesicles and were interpreted as efferent axons of postganglionic neurons with cell bodies in spinal ganglia. Lumbar afferents were most numerous in the trigone region, followed next by the ventral neck region; regions cranial to the ureters had similar small populations of lumbar afferents. A similar distribution pattern was observed for terminal axons containing granular synaptic vesicles. The relative concentration of lumbar innervation caudal to the ureters seems to account for the increased density of terminal axons observed in this region. Lumbar afferents were distributed bilaterally to the bladder and were numerically similar within and outside muscle fascicles. Ultrastructural evidence supports the position that bladder receptors are free nerve endings except for sparse Pacinian corpuscles.
A scanning electron microscopic study of the extrapulmonary respiratory tract
Authors: Andrews Peter M. 
Published: February 2005

AbstractScanning electron microscopy, sometimes supplemented with transmission electron microscopy, was used to study the ultrastructural morphology of the extrapulmonary respiratory tract. Material for observation was taken from male rat respiratory tracts which were fixed in situ and critical point‐dried. Goblet cells, brush cells, potential ciliated cells, ciliated cells, cornified vestibule cells and the olfactory mucosa could be distinguished by their characteristic surface morphologies. The distribution of these various cell types throughout the extrapulmonary respiratory tract is described. Transmission electron microscopy of material treated with ruthenium red reveals that a polyanionic surface layer coats all cilia, microvilli and the intervening cell surfaces on all cell types found in the nasal cavities, trachea and extrapulmonary bronchi.
Circadian rhythm of glycogen in the immature rat uterus: Effects of estrogen administration
Authors: Hoopes Phillip C. , Bo Walter J. , Krueger Wayne A. 
Published: February 2005

AbstractThe glycogen concentration in the immature rat uterus was investigated at three‐hour intervals over a 24‐hour period. Control animals received injections of 0.1 ml of oil while 0.06 μg of 17β‐estradiol was administered to experimental rats; the animals were sacrificed 24 hours later. Peak concentrations were observed at 9 a.m. for both control and experimental groups. The low value for controls appeared at 12 p.m. and for experimentals at 3 a.m. The difference between low and high points represented a 102% increase for controls and 59% for estradiol‐treated rats. These data show that a circadian rhythm is present in the rat uterus and that the uterus of the immature rat responds differently to estrogen stimulation according to the time of day the hormone is given.
The anatomy and innervation of the sphincter of oddi in the dog and cat
Authors: Kyösola Kimmo , Rechardt Leena 
Published: February 2005

AbstractThe fine morphology of the choledocho‐duodenal junctions of dogs and cats was studied by means of microdissection, classical histological staining techniques and by demonstrating in serial sections non‐specific cholinesterases, which stain the smooth muscle components excellently. The inbuilt cholinergic nervous apparatus was studied in serial sections by demonstrating acetylcholinesterase. By combining these methods, the three‐dimensional structural arrangement of the intrinsic cholinergic innervation system, with reference to the various substructures to be innervated, could be studied and mapped in detail.The most important features in the morphology, with respect to the function, were the tapering of the terminal ductus choledochus into a nozzle, the existence of concentric retrograde saccules around the ampulla and the intramural part of the bile duct, and the complex construction of the sphincters. Normally such a structure makes possible an active suction‐pressure pumping for evacuation of bile and pancreatic juice, being at the same time effective in preventing regurgitation of the duodenal fluid. On the contrary, if the orificium of the ampulla is obstructed, this structural arrangement probably facilitates regurgitation, especially into the pancreatic duct.The intrinsic cholinergic nervous apparatus of the choledocho‐duodenal junction was extremely rich, especially if compared with the cholinergic innervation of the muscular layer of the gut wall. This can probably be considered as an indication of complex motor (and possibly associated sensory) functions of the sphincters, in contrast to only slow gross contractions of the gut.To summarize: both morphological and neuroanatomical bases seem to be provided for rhythmic suction‐pressure pumping as well as for sensitive protective reflex functions in the choledocho‐duodenal junctions of the dog and cat. The finely graded complex interactions of the various muscle components are regulated by connecting and integrating neural elements between the individual smooth muscle units.
Effects of cytochalasin B on the fine structure of organized endodermal cells of the early chick embryo
Authors: Stagno Paul A. , Low Frank N. 
Published: February 2005

AbstractFresh pullet eggs (White Leghorn) were incubated for 36 to 48 hours. The blastoderms were exposed to cytochalasin B (CB), 10 or 40 μg/ml, for 2, 5, and 15 minutes prior to fixation by immersion in buffered chick Ringers solution containing CB, previously dissolved in dimethysulfoxide (DMSO), or by sub‐blastodermic injection. Controls fixed in ovo possess relatively flat surfaces with bulges due to uptake of yolk. Numerous microappendages (blebs, microvilli and ruffles) are present, especially at cell margins. DMSO‐controls present a similar cell surface except that small blebs are more prominent. The plasmalemmas of CB‐treated endodermal cells possess numerous large blebs (2‐10 μm in diameter), smaller blebs (0.2 μm) and microvilli. Cell dissociation occurs in selected areas resulting in rounded cells, devoid of microappendages, with peripheral processes. Transmission electron microscopic preparations of tissues similar to those used for scanning electron microscopy reveal that large blebs are filled with membranous material. Microfilaments are present but lack their normal subplasmalemmal arrangement. Microtubules and other cell organelles are apparently unaffected by CB. Evidence in this study supports the concept that cytochalasin B exerts its influence through alteration of the plasmalemma.
Evolution of the endoplasmic reticulum during rat spermiogenesis
Authors: Clermont Yves , Rambourg Alain 
Published: February 2005

AbstractThe endoplasmic reticulum (ER) was stained selectively by a sequence of uranyl acetate, lead and copper citrate, according to the method of Thiéry and Rambourg ('76), and then investigated in 0.5 to 2.0‐μm‐thick sections with the transmission electron microscope. Examination of photographic stereopairs allowed a three‐dimensional visualization of the ER at various steps of spermiogenesis.During the Golgi and cap phases of spermiogenesis (steps 1–7, classification of Leblond and Clermont, '52a), the ER is distributed throughout the cytoplasm as a three‐dimensional network of spherical and tubular cisternae connected by narrow tubules. In addition, a close network of tubular cisternae is located along the convex surface of the Golgi apparatus and lines the plasma membrane. Where the cell membrane joins that of another spermatid to form an intercellular bridge, this network extends across the bridge.During the acrosome phase (steps 8–14), the cytoplasm contains an abundant ER that shows the following modifications: (A) Along the inside and outside of the caudal tube the cisternae form long tubes or plates which run adjacent and parallel to the microtubules. These cisternae are connected by delicate lateral anastomoses; (B) Along the flagellum the ER forms a “fenestrated sleeve” made up of a close network of tubular cisternae; (C) Similar networks are organized as “fenestrated spherules” enclosing large vesicles seen throughout the cytoplasm; (D) At a short distance from the flagellum, the ER cisternae are continuous with a stack of annulate lamellae and an aggregate of radially arranged collapsed cisternae called the “radial body”.During the last or maturation phase (steps 15–19), the ER regresses. Thus, during the final steps in the formation of the flagellum, the ER network fragments and then most of the cisternae disappear from the cytoplasm. The “radial body” is the last element of the ER to be dissolved. Thus the ER undergoes extensive structural modifications during spermiogenesis, suggesting an active contribution of this organelle to the differentiation of the spermatid into a spermatozoon.
Qualitative and quantitative morphologic study of peyer's patches of the mouse after neonatal thymectomy and hydrocortisone injection
Authors: Abe Kazuhiro , Ito Takashi 
Published: February 2005

AbstractPeyer's patches in normal adult mice, neonatally thymectomized mice and mice injected with hydrocortisone were studied qualitatively and quantitatively by light microscopy. The patch was divided into germinal center, follicular area, parafollicular area and dome area. In normal mice, the volumetric ratio of the germinal center to the entire patch was 30.9%; that of the follicular area, 33.3%; that of the parafollicular area, 27.7%; and that of the dome area, 8.2%. Thymus‐dependent small lymphocytes were 40% of small lymphocytes in the patch. Out of the total thymus‐dependent small lymphocytes in the patch, 13% were included in the germinal center; 19%, in the follicular area; 62%, in the parafollicular area; and 6%, in the dome area. Hydrocortisone‐sensitive small lymphocytes were 65% of the total small lymphocytes in the patch, the germinal center contained 9%; the follicular area, 84%; the parafollicular area, 2%; and the dome area, 5%. The epithelium over the dome area was invaded by numerous small lymphocytes. Forty‐eight percent of lymphocytes within the epithelium over the dome were thymus‐dependent and 67% were hydrocortisone‐sensitive.It is concluded that Peyer's patch may be considered as a peripheral lymphatic tissue, functionally as well as morphologically.
The spiral constrictor of the gastroesophageal junction
Authors: Jackson Arthur J. 
Published: February 2005

AbstractThe gastroesophageal region was reconstructed from the histological analyses of five human newborn infants. In addition, the musculature of eight (3 newborn and 5 adult) human stomachs obtained from autopsies, with the lower one‐third of the esophagus attached, was dissected with the aid of a binocular dissecting microscope.The muscularis mucosae, in the region of the gastroesophageal junction, exhibited no increase in thickness, nor was there any indication of special mucosal folds. In addition, the gastroesophageal junction contained no morphologic evidence that would support the existence of an anatomic sphincter (a localized thickening of circular muscle fibers). However, the obliquely arranged inner circular muscle fibers of the esophagus separated into fascicular bundles below the esophageal opening. Some of the fasciculi, as they descended, again became circular in shape and continued into the stomach, forming the middle circular muscle layer, while other fasciculi maintained their oblique course toward the left surface of the esophagus. These fasciculi, coursing on the anterior and posterior surfaces of the esophagus, crossed and interdigitated along the left surface of the esophagus in the region of the incisura cardiaca. After crossing, the oblique fasciculi descended into the stomach forming the inner oblique muscle layer. Based upon this description of crossing and interdigitating fasciculi, it is suggested that closure of the gastroesophageal junction may be due to contraction of spirally arranged muscle. Since the term “sphincter” generally implies a circular structure, it is proposed that the term “spiral constrictor” be considered in naming this anatomical arrangement.
Effects of therapeutic radiation on microstructure of the human mandible
Authors: Savostin‐Asling Irene , Silverman Sol 
Published: February 2005

AbstractMandibular bone from eight patients who had received therapeutic radiation (6,000–7,200 rads) for intra‐oral cancer was obtained at surgery (1 month to 9 years after radiation) and compared histologically with non‐irradiated mandibular bone from five subjects. Measurements made on the nternal remodeling process of cortical bone included the extent of internal surface and the fraction indicating resorption, and the proportions of osteones which were incomplete (less than 3/4 filled with matrix), complete, and plugged. Appreciable differences were observed in all parameters except plugged osteones. The findings suggested early cessation of osteogenesis, and somewhat later cessation of resorption, without subsequent resumption of either process. The histologic appearance of the osteoblasts, osteoclasts, and osteones was in accord. Microfractures found in the irradiated bone were not seen to have healed. Radiation damage to the osteoprogenitor cells is postulated.
Elimination of multiple innervation in the developing avian superior oblique muscle
Authors: Holt R. K. , Sohal G. S. 
Published: February 2005

AbstractMotor endplates in the developing avian superior oblique muscle first appear on day 18 of incubation. Most of the endplates from this time through hatching (day 27) are innervated by multiple fibers. Each endplate in the post‐hatching period is innervated by only one fiber. Time of elimination of multineuronal innervation does not correlate with the time of trochlear neuron loss; the former occurs much later in development. Removal of multiple innervation is therefore, not the cause of the naturally occurring neuron loss.
Ultrastructure of Merkel corpuscles and so‐called “transitional” cells in the white leghorn chicken
Authors: Saxod Raymond 
Published: February 2005

AbstractIn the chicken Merkel corpuscles are located in the dermis and consist of specialized Merkel cells, discoid nerve endings and lamellar cells. Merkel cells contain characteristic membrane‐bound dense‐core granules and bundles of microfilaments. Asymmetric junctions, synapse like, with thickened membranes and clusters of dense‐core vesicles were observed between the Merkel cells and the nerve endings. The nerve ending is derived from myelinated nerves and sometimes contains clusters of clear vesicles. A laminar system formed by lamellar cells of the Schwann cell type encloses the Merkel cells and the nerve endings. So called “transitional” cells, showing some of the morphological features of both keratinocytes and Merkel cells, were observed in the basal layer of the epidermis. One was located partly in the epidermis and partly in the dermis. The structure of Merkel corpuscles is compared with that of Merkel cells in other tetrapods. The developmental significance of “transitional” cells and the origin of Merkel cells are discussed.
Development of the diarthrodial joints in the rat embryo
Authors: Mitrovic D. 
Published: February 2005

AbstractThe development of appendicular synovial joints of both legs was studied with histological and histochemical techniques in 43 rat embryos aged 12 to 21 days. From this and previous studies, it appears that joints develop by a sequence of cellular events leading to a full expression of the phenotypic characteristics. The classically described stages: cell condensation, three layered mesenchyme, vascular invasion and joint clefting, were chronologically recorded in all joints. The observations relevant to the intra‐articular structures, such as joint capsule, menisci and ligaments, were also presented. Previously unreported, cellular aspects were described during joint morphogenesis and their biological significance was discussed. Among these cellular aspects, of particular interest are: a. an early wave of cell necrosis occurring immediately after differentiation of the interzone. Disappearance of necrotic cells is thought to prevent chondrification of this tissue by clearing up the cells with chondroblastic potentialities; and b. a morphologically peculiar type of cells that differentiate alongside, and by the time of, clefting and seem to be related to this process. Thus, the joint clefting appears also to result from a cell‐tissue related phenomenon, acting in conjunction with the joint motion, the importance of which has been previously demonstrated.
Glucocorticoid‐induced alterations in collagen of neonatal mouse condylar cartilage
Authors: Lewinson Dina , Silbermann Michael 
Published: February 2005

AbstractNeonatal mice were treated with a single dose of triamcinolone hexacetonide, a long‐acting synthetic analogue of cortisol, and their mandibular condyles were studied ultrastructurally ten days thereafter. A pronounced decrease in the number and size of matrix granules (proteoglycans) was found in the cartilaginous matrix of triamcinolone‐treated condyles. In contrast, a marked increase concomitant with significant structural changes was noted in collagen fibrils. An obvious enhancement of collagen fibrillogenesis was noticed in the pre‐mineralizing extracellular matrix. Atypical, wider than normal, banded collagen fibrils were found to form dense meshworks which appeared to lack any specific orientation or organization. It is proposed that glucocorticoid hormones, given systemically to neonatal mice, interfere with regulatory mechanisms involved with the biosynthesis of cartilaginous matrical macromolecules, i.e., proteoglycans and collagen and thereby promote certain aging processes within active growth centers.
Postnatal development of the granule cell in the kitten cerebellum
Authors: Smith Diane E. , Downs Irene 
Published: February 2005

AbstractNewborn to 9‐week‐old kittens were anesthetized and then sacrificed by inserting a scalpel into the thoracic cavity and severing the descending aorta. The cerebella were removed and processed according to Golgi‐Cox and rapid Golgi modifications. The results indicate that the dendritic processes of the granule cells undergo a marked postnatal maturation even though there is little postmigratory change in the size and shape of the cell body. A clubshaped swelling of the distal portions of the dendrites is observed by the end of the first week; this “claw” becomes multilobated by three weeks and displays elaborate digitiform projections by nine weeks. The sequence of postnatal development in the kitten appears to follow a time course similar to that observed in other species. A possible correlation between the postnatal development of the granule cell and the postnatal development of the spincocerebellar system is discussed.
Scanning electron microscopy of epidermal cell migration in wound healing during limb regeneration in the adult newt, Notophthalmus viridescens
Authors: Repesh Lillian A. , Oberpriller Jean C. 
Published: February 2005

AbstractThe epidermal cells which migrate over the wound surface of the amputated limb of the adult newt were examined using the scanning electron microscope. Specimens were prepared routinely for scanning electron microscopy or were embedded in Epon 812 for light microscopic observations. A cuff of epidermal cells was seen at the edge of the wound, from which cells appeared to migrate over the wound surface. As early as five hours after transection of the limb, the basal layers of this cuff appeared to send out pseudopodial projections. These seemed to establish a physical contact with a fibrin‐like substratum, which apparently served as a means of support for the migrating cells. Subsequently, the epidermal cells became elongate and had the appearance of streaming toward the center of the wound. Between 10 and 13 hours post‐amputation, the cells in the central region of the stump were rounded up and some possessed microappendages resembling microplicae and microvilli. Throughout the entire period of wound coverage, the cells seemed to maintain contact with the fibrin network, which appeared to be the first structural element of wound architecture. As a result of these observations, the mechanism by which the epidermal cells migrate has been clarified.