bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructure of the glomus cells in the carotid body of chronically hypoxic rats: With special reference to the similarity of amphibian glomus cells
Authors: Kusakabe Tatsumi , Powell Frank L. , Ellisman Mark H. 
Published: February 2005

AbstractThe ultrastructural characteristics of the glomus cells in the rat carotid body exposed to extremely long‐term hypoxia (10–12 weeks) were investigated. The glomus cells could be classified into four distinct types according to the shape of dense‐cored vesicles in the glomus cell cytoplasm: (1) small vesicle cells (SVCs, 50 nm in mean diameter), (2) large vesicle cells (LVCs, 80 nm in mean diameter), (3) dilated eccentric vesicle cells (EVCs, 400–800 nm in diameter), and (4) mixed vesicle cells (MVCs, large and eccentric vesicles). Many clusters of glomus cells were found to contain all four categories of cell types. The appearance of EVCs was a unique and common characteristic of glomus cells in this long‐term hypoxia model. We also noted other ultrastructural features with chronic hypoxia which are characteristic of the amphibian carotid labyrinth glomus cells: (1) incomplete covering of glomus cells with the supporting cell missing over a wide area, (2) long thin cytoplasmic projections in the intervascular stroma, and (3) intimate apposition of the glomus cells and pericytes (g‐p connection), endothelial cells (g‐e connection), plasma cells, and fibrocytes. Because arterial PO2 is generally low in amphibia, these may be general features of hypoxic adaptation and facilitate both uptake of oxygen from blood and release of catecholamine into the blood. The g‐p and g‐e connections may take part in the regulation of the microcirculation in the enlarged carotid body. © 1993 Wiley‐Liss Inc.
Posterior pituitary of the newborn marsupial possum, Trichosurus vulpecula
Authors: Gemmell R. T. , Chua T. , Bathgate R. A. D. , Sernia C. 
Published: February 2005

AbstractThe fetal anterior pituitary‐adrenal axis is thought to be involved in the initiation of birth in both eutherian and marsupial mammals. Little is known about the structure and function of the posterior pituitary at birth in the marsupial. Immunocytochemistry, high pressure liquid chromatography, and radioimmunoassay were used to identify vasopressin and mesotocin in the posterior pituitary of a newborn marsupial, the brushtail possum, Trichosurus vulpecula. The concentrations of vasopressin and mesotocin in the head of the newborn possum were 0.34 and 0.28 ng, respectively. The concentration of vasopressin was always greater than that of mesotocin, and the amounts of neuropeptides present in the head increased as the possum developed. © 1993 Wiley‐Liss Inc.
Unique features of the cauda epididymidal epithelium of hibernating bats may promote sperm longevity
Authors: Crichton Elizabeth G. , Suzuki Fumie , Krutzsch Philip H. , Hammerstedt Roy H. 
Published: February 2005

AbstractMeasurements of extremely high osmolalities in cauda epididymidal fluids of hibernating bat species led to an investigation of the junctional complex morphology of the epithelium of this sperm storage site. Freeze fracture replicas revealed the presence, at certain times of the year, of a tight junction architecture that resembled that traditionally thought to be exclusive to the blood‐testis barrier, the strongest permeability barrier in the body. It is hypothesized that seasonal establishment of these specialized Sertoli cell‐like tight junctions is necessary to the maintenance of the high osmotic state of the luminal environment, allowing for the prevention of dilution of its contents by paracellular routes and its protection from bursting under the osmotic pressure contained within. © 1993 Wiley‐Liss, Inc.
Immunoelectron microscopy on the localization of endothelin in the umbilical vein of perinatal rabbits
Authors: Sakamoto Yoshitaka , Doi Yoshiaki , Ohsato Keiichi , Fujimoto Sunao 
Published: February 2005

AbstractImmunoelectron microscopic localization of endothelin (ET) using the mouse monoclonal anti‐ET sera was performed on the pre‐and postnatal rabbit umbilical vein during stages when Weibel‐Palade (WP) bodies increase in number in the endothelial cells.The immunoreactions are localized in the rough endoplasmic reticulum, Golgi cisterns, and WP bodies that are actively segregated from the Golgi apparatus. After degranulation and extracellular release of WP bodies was induced by compound 48/80, heavy immunoreactions were seen in both vascular lumen and cytoplasm near the degranulated WP bodies. These results indicate that ET is stored in WP bodies after segregation from the Golgi apparatus and released from the endothelial cells concomitantly with other components of these granules by exocytosis.Because the immunoreactions are also seen in pinocytotic vesicles that are occasionally in contact with WP bodies, it seems likely that WP bodies are also involved in the uptake and storage of ET from blood plasma. © 1993 Wiley‐Liss, Inc.
Morphologic basis for loss of regulated insulin secretion by isolated rat pancreatic islets
Authors: Pai Gokul M. , Slavin Bernard G. , Tung Paul , Volk Bruno W. , Johnson Daisie G. , Anderson Deborah G. , Levin Seymour R. 
Published: February 2005

AbstractLaboratories engaged in secretory studies of rat pancreatic islets often encounter high baseline insulin secretion with poor secretory response to secretagogues, such as glucose. The specific morphologic abnormalities that accompany this unregulated release have not been described. We isolated islets comparing two approaches. Both used stationary digestion with collagenase. In method I, we distended the biliary duct extracorporeally with collagenase and minced the pancreas after a 28 min digestion (37°C). In method II, we distended the pancreas intracorporeally and digested for 40 min without mincing. Both methods utilized a similar collagenase concentration (2 μg/ml in Hank's balanced salt solution (HBSS)). Both methods yielded over 300 islets/rat. Islets from both methods appeared intact, when viewed under the dissecting microscope. We found that adequate secretion from incubated islets was evoked with method I, i.e., low basal insulin levels at low glucose (3.3 mM), tripling at 11.0 mM glucose, and nearly quadrupling in response to higher glucose (16.7 mM). In contrast, method II was characterized by high basal levels without response to higher glucose. Ultramicroscopic examination of islet B cells in method I revealed normal cytological features, while B cells in method II showed marked degranulation, profiles of swollen endoplasmic reticulum, and swollen mitochondria. Morphometric analysis of B cells confirmed quantitatively a decrease in secretory granule density and mitochondrial enlargement in method II compared to method I. Anatomic changes, largely confined to the B cells of islets may account for functional alterations of responses. Defects cannot be predicted from gross appearance of islets. © 1993 Wiley‐Liss, Inc.
Further studies on the kidney of the hook‐lipped African rhinoceros, Diceros bicornis
Authors: Maluf N. S. R. 
Published: February 2005

AbstractA healthy, pregnant Diceros bicornis (No. 29455), with histologically normal but relatively large kidneys containing a correspondingly large number of nephrons, died suddenly from an injury. Renal lobation was studied partly from serial transverse cuts across the kidney. The fibromuscular pelvic conduits, which are a craniocaudal bifurcation of the ureter, are associated with prominent longitudinally disposed paraconduital veins which anastomose with the interlobar veins. The arcuate veins open widely into the paraconduital veins. The latter drain into the major tributaries of the renal vein at the renal sinus. The interlobar arteries enter the parenchyma through the interlobar septa. These arteries release internal perforator branches, through the septa, which pass to the corticomedullary border, branch along that border as arcuate arteris, and release cortical branches centrifugally. All these branches give off twigs to the glomeruli.Relative renal mass of mammals is inversely proportional to their adult body mass. This is indicated by a regression line which includes rhinoceroses. D. bicornis No. 29455, accordingly, has exceptionally large kidneys.The mesonephros of the 75 mm fetus of D. bicornis has mature glomeruli and tubules. The metanephros has pelvic conduits, paraconduital veins, but, as yet, no medullary loops. © 1994 Wiley‐Liss, Inc.
Arrangement and innervation of the glutei medius and minimus and the piriformis: A morphological analysis
Authors: Akita Keiichi , Sakamoto Hirokazu , Sato Tatsuo 
Published: February 2005

AbstractIn order to examine the relationships between the positional arrangement and supplying nerves of the glutei medius and minimus and the piriformis, we investigated 49 pelvic halves of 28 cadavers. The superior gluteal nerve ran on the ventral surface of the piriformis in 44 cases (89.8%) (Type A), and some branches of the nerve perforated the piriformis in five cases (10.2%) (Type B). Based on the detailed findings of the innervation of the three muscles, the piriformis is chiefly composed of the caudal element of the gluteus medius (Type A) and in some cases the caudal element of the gluteus minimus as well (Type B). © 1994 Wiley‐Liss, Inc.
Ultrastructure as a basis for dating of rat endometrium
Authors: Spornitz U. M. , Rinderknecht B. P. , Edelmann A. , Scheidegger B. , Cairoli F. 
Published: February 2005

AbstractStudies on the endometrial cycle depend upon the precise dating of the cycle stage. In the present paper the generally applied method of vaginal smear was carefully verified through the measurement of the hormones relevant to the endometrial cycle. From rats predated through vaginal smear cytology, the hormone levels of estradiol‐17‐beta (E2) and progesterone (P), luteinizing hormone (LH), and follicle stimulating hormone (FSH) were measured. The values obtained were then compared to the standardized values of our reference curve. Animals with values that did not fit within the standard deviation of our reference curve were excluded from this investigation. Thus, for the first time exactly dated rat endometrial morphology was studied with electron microscopy. The morphology of the surface epithelium of rat endometrium from all four stages of the cycle is described in detail. In addition, a semiquantitative morphometric analysis of the following parameters was performed: cell volume, nuclear volume, the volume density of secretory granules, digestive vacuoles, mitochondria, Golgi apparatus, rough endoplasmic reticulum, and lipid vacuoles as well as the size of lipid vacuoles. With the cellular content of lipid vacuoles and their diameter, it is possible to differentiate between proestrus/estrus and diestrus I/diestrus II, the latter possessing definitely more and larger lipid vacuoles. During estrus the greatest cytoplasmic volume develops. In addition to this, secretory granules are only present during estrus. Finally, diestrus I can be well differentiated from diestrus II, because diestrus I exhibits more digestive vacuoles and during diestrus II a high percentage of free ribosomes is present. On the basis of distinct morphological features, described in this paper, it is now clearly possible to distinguish between the four different cycle stages. © 1994 Wiley‐Liss, Inc.
Postnatal differentiation and development of the rat epididymis: A stereological study
Authors: Jiang F. X. , Temple‐Smith P. , Wreford N. G. 
Published: February 2005

AbstractPostnatal development and differentiation of the rat epididymis was studied in the rat from 15 to 120 days of life using stereological techniques. Both the relative volume (volume density) and absolute volume of the epithelial, interstitial, and luminal compartments in the initial segment, caput, corpus, and cauda epididymides were determined. In all segments the volume density of the epithelial compartment increased between days 15 and 30 before falling to adult values at 45 days in the initial segment (0.476 ± 0.031), at 60 days in the caput (0.258 ± 0.028) and at 90 days in the corpus (0.245 ± 0.007) and cauda (0.140 ± 0.004). The relative volume of the interstitium decreased, whilst that of the lumen increased over the same period with adult values being achieved earlier in the proximal segments than in the distal segments. In contrast to volume fraction the absolute volume of all compartments in all segments increased from day 15 to day 90. Between 90 and 120 days the absolute volumes of compartments in the initial segment and caput showed little volume change. All compartments in the corpus and cauda showed significant increases in volume over the same period. A similar pattern of development was observed with respect to the surface area of both the luminal and basement membrane aspects of the epithelium; surface area per unit volume (surface density) in all segments reached adult values at approximately 60 days, whilst the increase in absolute area of the surfaces ceased at 90 days in the initial segment and caput and continued to 120 days in the corpus and cauda. The total length of the epididymal tubule showed the same pattern with no increase in length apparent in the initial segment and caput after 90 days. Length however continued to increase in the corpus and cauda between 90 and 120 days. Tubule and luminal diameter reached their definitive values in the initial segment on day 60 but continued to increase until day 90 in the distal segments. Epithelial height increased between 15 and 30 days in all segments; in the caput, epithelial height was greatest on day 30 before decreasing slightly; and in the corpus and cauda maximal epithelial height was observed on day 45 decreasing to stable values on day 60 and 90, respectively. All the data is consistent with a proximal to distal differentiation and development of the epididymis with growth continuing in all segments after the establishment of the definitive architecture. Growth of the distal segments continued after its cessation in the proximal segments. © 1994 Wiley‐Liss, Inc.
Quantitative study on the relation between structural and functional properties of the hearts from three different mammals
Authors: Kim Ho‐Dirk , Kim Chul Ho , Rah Bong‐Jin , Chung Hae‐Ik , Shim Tae‐Sub 
Published: February 2005

AbstractThe ultrastructural quantitative composition of left ventricular cardiac myocytes from isolated Langendorff‐perfused hearts was studied in three different mammals (rabbit, guinea pig, and rat). Volume densities of mitochondria, myofibrils, and unspecified cytoplasm were determined using morphometry and were compared to functional parameters including left ventricular developed pressure (LVDP), contractility (dP/dt), heart rate, TTI (tension‐time index, an index of oxygen consumption), and relative heart mass (H/B) obtained from these hearts. Each of the mammals was found to possess a very specific and characteristic quantitative composition of cardiac myocyte. Cardiac myocytes contained 26.8% mitochondria and 56.3% myofibrils in rabbits, 25.8% mitochondria and 60.9% myofibrils in guinea pigs, and 27.7% mitochondria and 58.1% myofibrils in rats. The LVDP, contractility, heart rate, and TTI were quite different among species. However, there were close correlations between the mitochondrial volume density and the LVDP (p < 0.05), and between the mitochondrial volume density and the TTI (p < 0.05), in any group of the animals. It is concluded that the mitochondrial volume density is a good indirect indicator of function of cardiac muscle related to oxidative capacity. © 1994 Wiley‐Liss, Inc.
Calmodulin immunoreactivity in the chicken pineal gland: Comparison with calbindin‐D28k, calretinin, and S100
Authors: Bastianelli Enrico , Pochet Roland 
Published: February 2005

AbstractCalmodulin distribution in the chicken pineal organ was investigated by immunohistochemistry. Calmodulin immunoreactivity was detected in ependymocytes in the follicular zone and in interstitial cells in the parafollicular zone. No calmodulin immunoreactivity was detected in pinealocytes. Lack of calmodulin immunoreactivity in pinealocytes raises questions about its proposed function in melatonin synthesis as suggested by pharmacological studies using calmodulin antagonists. The calmodulin distribution was comparable to that of S100, a glial cell marker. Two other markers, calbindin‐D28k and calretinin, which in neuroanatomical studies give excellent cytoarchitectonic staining, in the chick pineal permitted the detection of two subclasses of pinealocytes. One was darkly stained by calbindin‐D28k and rare. The other was very abundant and calretinin positive. In the parafollicular zone, calbindin‐D28k and/or calretinin antibodies allowed us to visualize cells presenting a neuron‐like morphology. Calretinin immunoreactivity was detected in nearly all pinealocytes in which hydroxy‐indol‐O‐methyl transferase was also located. Comparison between the lack of calmodulin and the presence of calretinin, belonging to the same calcium‐binding protein family, in chick pinealocytes raises the hypothesis about a possible role of calretinin in melatonin synthesis. © 1994 Wiley‐Liss, Inc.
Size‐selective comparison of fetal calvarial versus adult marrow osteogenic colony‐forming entities
Authors: Dutra Timothy F. , Bernard George W. 
Published: February 2005

AbstractBackground: This experiment was designed to test whether a single cell suspension of adult marrow‐derived cells will form mineralized bone nodules in vitro. Methods: At the time of plating, cellular dispersions of either young adult rabbit bone marrow cells or, as controls, of fetal mouse calvarial cells were size‐selected by sieving through various poresize plastic meshes. Results: When marrow‐derived cells were passed through a 105 μm pore‐size mesh, fibroblastic cell cultures grew in vitro in six of six attempts; however, marrow cell clusters backwashed off 105 μm pore‐size meshes produced osteogenic colonies in vitro in six of six trials. Fetal calvarial cells filtered through a 30 μm pore‐size mesh yielded osteogenic nodules in culture in six of six tests. Conclusions: For adult bone marrow, cell clumps or clusters larger than 105 μm produced bone colonies under standard cell culture conditions, whereas for fetal calvarial cells, the initiating agent was smaller than 30 μm. © 1994 Wiley‐Liss, Inc.
A morphological study of the lymphocyte traffic in Peyer's patches after an in vivo antigenic stimulation
Authors: Regoli Marì , Borghesi Chiara , Bertelli Eugenio , Nicoletti Claudio 
Published: February 2005

AbstractBackground: Lymphoid cells have often been observed in the intestinal lumen and it has been hypothesized that M cells could represent one of the most important migration routes for the immunocompetent cells from the lymphoid follicle to the lumen. However, a direct evidence of the passage was lacking. In this study we describe a morphological analysis of the lymphocyte traffic in rabbit Peyer's patches after an in vivo stimulation with an antigen normally not present in the intestine.Methods: The antigenic stimulation of a large number of Peyer's patches was carried out using the isolated ileal loop technique and then the samples from stimulated and control Peyer's patches were analysed by light and transmission electron microscopy.Results: We have been able to describe details of lymphocyte migration through M cells, from the follicle to the intestinal lumen, and a marked increase of intraluminal lymphocytes by counting the immunocompetent cells after periods of antigenic stimulation of varying lengths.Conclusions: Our finding is that the passage of lymphocytes to the lumen is an antigen‐dependent event and we also provide direct evidence that M cells are one of the migration routes. Our observations also indicate that lymphoid cells in the intestinal lumen may play an immunologic role in mucosal immunity. © 1994 Wiley‐Liss, Inc.
The peripheral cytoplasm of adrenocortical cells: Zone‐specific responses to ACTH
Authors: Loesser Kathryn E. , Cain Lisa D. , Malamed Sasha 
Published: February 2005

AbstractBackground: Differences in the cytoskeletal protein actin in cells from the zona glomerulosa and zona fasciculata would be of considerable interest because there is persuasive evidence that rat corticosteroids are secreted by mechanisms that are somewhat zone‐specific. We have previously shown evidence that actin may be involved in steroid secretion, possibly in connection with changes in adrenocortical microvilli. However, the cells upon which the data were based were not separated according to zone of origin.Methods: Immunogold electron microscopy and morphometric procedures were used to determine whether ACTH‐induced changes in the peripheral cytoplasm of isolated adrenocortical cells occur in both zona fasciculata and zona glomerulosa cells.Results: Actin immunoreactivity was more concentrated in the cytoplasm adjacent to the plasma membrane (including the cytoplasm within the microvilli) than it was in the internal cytoplasm in cells from both zones (4–6 times more concentrated in zona glomerulosa cells and 3–6 times more concentrated in zona fasciculata cells). However, the mean aggregate microvillar surface length (microvillar index) of untreated zona fasciculata cells previously reported (Loesser and Malamed, 1987) was 23% greater than that of untreated zona glomerulosa cells. Although ACTH (at a maximal steroidogenic concentration) had no effect on the peripheral cytoplasmic actin concentration of zona glomerulosa cells, there was a 24% increase in the aggregate microvillar length. In contrast, in zona fasciculata cells, ACTH treatment was accompanied by an increase in peripheral cytoplasmic actin concentration of 58–64% and an increase in aggregate microvillar surface length of 40% (previously reported (Loesser and Malamed, 1987)), almost twice that for zona glomerulosa cells.Conclusion: The results suggest that ACTH‐induced hormone release from zona fasciculata cells is mediated by increases in peripheral cytoplasmic actin and aggregate microvillar length; in zona glomerulosa cells such changes are small or absent. © 1994 Wiley‐Liss, Inc.
Quantitative analyses of cell behaviors underlying notochord formation and extension in mouse embryos
Authors: Sausedo Roger A. , Schoenwolf Gary C. 
Published: February 2005

AbstractBackground: Formation and extension of the notochord (i.e., notogenesis) is one of the earliest and most obvious events of axis development in vertebrate embryos. In birds and mammals, prospective notochord cells arise from Hensen's node and come to lie beneath the midline of the neural plate. Throughout the period of neurulation, the notochord retains its close spatial relationship with the developing neural tube and undergoes rapid extension in concert with the overlying neuroepithelium.Methods: In the present study, we examined notochord development quantitatively in mouse embryos. C57BL/6 mouse embryos were collected at 8, 8.5, 9, 9.5, and 10 days of gestation. They were then embedded in paraffin and sectioned transversely. Serial sections from 21 embryos were stained with Schiff's reagent according to the Feulgen‐Rossenbeck procedure and used for quantitative analyses of notochord extension.Results: Quantitative analyses revealed that extension of the notochord involves cell division within the notochord proper and cell rearrangement within the notochordal plate (the immediate precursor of the notochord). In addition, extension of the notochord involves cell accretion, that is, the addition of cells to the notochord's caudal end, a process that involves considerable cell rearrangement at the notochordal plate‐node interface.Conclusions: Extension of the mouse notochord occurs similarly to that described previously for birds (Sausedo and Schoenwolf, 1993 Anat. Rec. 237:58–70). That is, in both birds (i.e., quail and chick) and mouse embryos, notochord extension involves cell division, cell rearrangement, and cell accretion. Thus higher vertebrates utilize similar morphogenetic movements to effect notogenesis. © 1994 Wiley‐Liss, Inc.