bluuebunny/crossref_metadata_2025_split huggingface dataset:
Continuous‐Perifusion tissue culture of fetal and adult pancreas of the lizard Anolis carolinensis
Authors: Rhoten William B. 
Published: February 2005

AbstractThe differentiation of the fetal saurian pancreas in continuousperifusion tissue culture (CPTC) was examined. Splenic pancreases from 24‐day postoviposition fetuses of the green anole, Anolis carolinensis, were grown for 8 to 31 days by CPTC following successful preliminary studies with adult pancreas. Adult anolian endocrine pancreas was maintained for up to 7 days by CPTC. The pancreatic explants were examined morphologically by light and electron micros‐copy. The functional integrity of the endocrine cells was evaluated by measuring hormone levels of the explants and in the basal medium and by determining the kinetics of hormone release. The pancreatic endocrine cells from fetal and adult anoles were functionally and morphologically intact after CPTC. The exocrine pancreas was not maintained during culture. This study demonstrates for the first time the growth of the reptilian endocrine pancreas in culture.
The vasculature of the human penis: A reexamination of the morphological basis for the polster theory of erection
Authors: McConnell Joann , Benson George S. , Schmidt Waldemar A. 
Published: February 2005

AbstractThe morphology of human penile blood vessels has been studied to characterize columns of smooth muscle found in the intima. Although previous workers (Kiss, 1921; Conti, 1952) termed these intimal pads or polsters and concluded that they were actively responsible for the production of erection, more recent work has questioned these conclusions (Benson et al., 1980; Newman and Tchertkoff, 1980).Serial sections were taken throughout the length of the penis from 11 cadavers and stained with various histopathological stains. Numerous polster‐like structures were found, but all could be identified as either branch points in vessels, intimal cushions located at branch points, or arteriosclerotic lesions at various stages of development. None of these structures seem capable of functioning in the manner attributed to them by Conti (1952) and others. Furthermore, comparison of the structures found in the present study to illustrations of polsters in Conti's paper suggest that these are identical.The present study refutes the polster theory of erection and leaves open to further question the mechanisms involved in the control of blood flow into and within the penis.
Proliferation of sertoli cells in fetal and postnatal rats: A quantitative autoradiographic study
Authors: Orth Joanne M. 
Published: February 2005

AbstractProliferation of Sertoli cells during fetal and postnatal development of the rat was examined and quantified with light microscope autoradiography. Fetuses in utero were injected subcutaneously with 3H‐thymidine. The percentages of Sertoli nuclei that had incorporated label were determined in auto‐radiographs from fetuses aged 16 through 21 days of gestation. To compare the degree of Sertoli cell proliferation during fetal development with that occurring after birth, pups were also studied at intervals between the day of birth and 3 weeks of age. For each fetus or pup, at least 500 Sertoli cell nuclei in each of three sections were scored as labeled or unlabeled. These data were subjected to analysis of variance and the Newman‐Keuls test. The percentage of Sertoli cells incorporating 3H‐thymidine increased progressively from day 16 of gestation onward, to a maximum of 26.8% on day 20, two days before birth. Thereafter, this percentage dropped steadily until, in pups 21 days after birth, no labeled Sertoli cells were detected. These findings highlight the fetal period as the time of greatest expansion of the Sertoli cell population and indicate that, at birth, proliferation of these cells is already on the decline.
Light microscopic morphometric analysis of rat ileal mucosa: II. Component quantitation of Paneth cells
Authors: Rodning Charles B. , Erlandsen Stanley L. , Wilson I. Dodd , Carpenter Anna‐Mary 
Published: February 2005

AbstractA quantitative light microscopic morphometric analysis of lysozyme‐ and IgA‐containing Paneth cells within the ileal mucosa of physiologically manipulated and control (sham operation) animals was performed. The experimental groups of rats included animals raised in a gnotobiotic environment (microbial reduction) and animals with ileal self‐filling blind (microbial proliferation) and Thiry‐Vella (intestinal discontinuity) loops. The unlabeled antibody enzyme immunohistochemical localization technique was employed for the identification of intracellular lysozyme and IgA. Component quantitation was performed by use of a micrometer component quantitator.Marked Paneth cell hyperplasia was noted in association with gnotobiosis and with the Thiry‐Vella fistula. This observation quantitatively confirms previous subjective impressions of increased Paneth cell differentiation in association with those physiologic states. Since the neurovascular component of the Thiry‐Vella fistula is intact, the normal intraluminal succus entericus would appear to be involved in modulation of Paneth cell differentiation. The recognition of Paneth cell hyperplasia in association with the Thiry‐Vella fistula suggests that this may be a useful experimental model for an evaluation of the life cycle and functional characteristics of this cell population.The results also revealed that no significant change in the volume percentage of Paneth cells and a decreased volume percentage of Paneth cells containing IgA occurred in association with the self‐filling blind loop. A decreased volume percentage of IgA‐containing immunocytes in association with the blind loop has previously been reported. The data are most consistent with the interpretation that the Paneth cell and immunocyte response to antigenic stimulation are interrelated and that the Paneth cell population has a restricted latitude of response to microbial proliferation.
Pancreatic polypeptide (PP)‐like immunoreactivity in the Pancreatic islets of the anglerfish (Lophius americanus) and the channel catfish (Ictalurus punctatus)
Authors: Johnson Dana E. , Noe Bryan D. , Bauer G. Eric 
Published: February 2005

AbstractPancreatic polypeptide (PP) immunoreactivity was demonstrated in the endocrine pancreas of the anglerfish (Lophius americanus) and the channel catfish (Ictalurus punctatus) using immunohistochemistry. In both species, PP‐immunoreactive cells were localized at the periphery of endocrine tissue. In Lophius americanus, PP‐immunoreactivity could be localized in the principal islet, the pyloric or secondary islet, and the mesenteric or tertiary islets. A peripheral localization of PP‐immunoreactive cells having characteristic angular, or dendritic, appearance demonstrated in the above two species are a common finding among many teleost species. This peripheral localization of cells, particularly in principal (splenic) anglerfish islets, make them an ideal source of islet tissue which can be easily enriched or depleted of pancreatic polypeptide‐containing cells for use in studying the synthesis and secretion of islet hormones.
Concanavalin a receptor sites on lymph node cells in vivo and in vitro
Authors: Sun Donald C. , Leak Lee V. 
Published: February 2005

AbstractThe distribution and density of receptors for concanavalin A (Con A) on the surfaces of cells of intact and isolated popliteal and axillary lymph nodes were investigated in the rabbit. Intact lymph nodes were perfused via the subcapsular (marginal) sinus with either Con A peroxidase or Con A ferritin, fixed with glutaraldehyde, and processed for electron microscopy. Both Con A peroxidase and Con A ferritin were distributed on the plasmalemma of lymphocytes, macrophages, neutrophils, plasma cells, reticular endothelial cells, and the vascular endothelium.Counts of Con A‐conjugated ferritin particles indicated that the density of Con A receptors was generally similar for lymphocytes, macrophages, and neutrophils but lower on plasma cells. When lymph node cells were isolated by mechanical methods and exposed to Con A ferritin, the label was homogenously distributed on the cell surfaces of most cells. However, Con A binding was significantly higher on the surface of isolated cells than in the intact node. It is suggested that the increase in density of Con A binding sites on isolated cells may possibly be due to an unmasking of cell surface moieties in which additional Con A receptor sites become available as a result of the isolation procedure. The density of Con A ferritin binding sites was also significantly lower on the surface of isolated plasma cells than the lymphocyte and macrophage, suggesting that the density distribution of cell surface saccharides is different for various lymphoid cells.
Otoconial morphology of the developing chick
Authors: Ballarino Joanne , Howland Howard C. 
Published: February 2005

AbstractWe examined with scanning electron microscopy the otolithic organs of chick embryos aged 6 to 21 days. Otoconial forms not previously reported in adult birds or mammals were found. On the basis of the size and prevalence of various types of otoconia at different embryonic stages we organized the otoconial forms into a possible growth sequence starting with an early “double‐fluted” or skeletal form and terminating with the normal mature form found in adults.
Myocardial infarction in dogs with acute and gradual occlusion of the circumflex or right coronary arteries
Authors: Wilson Jack L. , Scheel Konrad W. 
Published: February 2005

AbstractThis study was designed to quantitate and describe the incidence and magnitude of myocardial infarction in the canine heart following acute and gradual occlusion of the circumflex or right coronary arteries. In animals with acute occlusion, the circumflex artery was ligated just distal to the bifurcation of the left coronary artery for 4 hr (seven dogs). Gradual occlusion was produced by placing an Ameroid occluder on the circumflex artery for 1 month (nine dogs), 3 months (nine dogs), and 5 months (eight dogs) and on the right coronary artery for 3 months (nine dogs). Ten dogs served as controls. At the end of the experiments the dogs were sacrificed, and identification of myocardial infarction was made with an enzyme‐mapping technique in dogs with acute occlusion and with histological methods in dogs with gradual occlusion. The volume of ventricular infarction was determined with the use of an Apple II Computer and graphics tablet. After 3 months, gradual occlusion of the right coronary artery produced a 22% incidence of infarction which was significantly less (P <.01, X2) than the 67% incidence observed with 3 months of gradual circumflex occlusion. The average infarct volume produced by gradual right coronary occlusion was 0.94 + 0.69%. The average volume of left ventricular infarction in animals with circumflex acute occlusion was 15.6% + 6.6 and the incidence of infarction was 100%. With gradual occlusion of the circumflex artery for 1, 3, and 5 months, average left ventricular infarction was 2.02 ± 1.01%, 3.13 ± 1.53%, and 2.96 ± 1.35%, respectively. There were no significant differences in the amount of damage observed among the three groups with gradual occlusion, and the average incidence of infarction for these three groups was 76%. In the 1‐, 3‐ or 5‐ month animals with circumflex occlusion, no additional areas of necrosis subsequent to the original damage were found, indicating that infarction is a single event in this model of gradual occlusion. These results suggest that infarct size is determined primarily by factors at the time of total occlusion and that gradual occlusion allows sufficient time for collateral growth, thereby limiting the extent of myocardial injury.
Newt forelimb cartilage regeneration after partial denervation
Authors: Egar Margaret , McCredie Janet , Singer Marcus 
Published: February 2005

AbstractWeekly operations to remove the fourth spinal nerve and prevent its contribution to the neutrotrophic factor available at the amputation stump of the newt arm resulted in significantly smaller regenerates with significant skeletal deficiencies in all four digits when compared to the unoperated control regenerate arm. The fourth nerve deficient arms had more than twice as many gross malformations as did the controls. These effects of partial denervation give tentative support to an hypothesis of neurotome subtraction that suggests a decisive role for nerves in determination of limb tissue.
Morphometric analysis of testicular Leydig cells in normal adult mice
Authors: Mori H. , Shimizu D. , Fukunishi R. , Christensen A. Kent 
Published: February 2005

AbstractStereological analysis was carried out on Leydig cells in perfusion‐fixed testes of normal adult mice.In a decapsulated testis, the seminiferous tubules occupy 89.3% and the interstitial tissue makes up 10.7% of the volume of the testis parenchyma. The Leyding cells comprise 3.8% of testicular volume. There are 24.9 million Leydig cells per cm3 (or gm) of tissue. An average Leydig cell has a volume of 1,533 μm3 and a surface area of 1150 μm2.The smooth endoplasmic reticulum (SER) is the most prominent organelle in the Leydig cells, and has a membrane surface area of 2,428 cm2 per cm3 of fresh testis tissue, which is 8.5 times the surface area of the plasma membrane and constitutes 56.9% of the total membranes in Leydig cells. Mitochondria occupy 10.1% of the Leydig cell volume of 11.4% of cytoplasmic volume. The inner mitochondrial membrane (including tubular or vesicular cristae) provides a surface area of about 2855 μm2/cell and is 2.26 times that of the outer membrane. There are approximately 712 cm2 of inner membranes per cm3 tissue. Mouse Leydig cells have numerous lipid droplets, which average 147 per cell and occupy 5.1% of the cell volume.
Species differences in the synaptic membranes of the end bulb of held revealed with the freeze‐fracture technique
Authors: Mattox D. E. , Neises G. R. , Gulley R. L. 
Published: February 2005

AbstractTwo morphological differences distinguish the membranes of the end bulb‐spherical cell synapse in rats and mice from those in guinea pigs and chinchillas. First, in freeze‐fracture replicas, the membranes of rat and mouse spherical cells lack perisynaptic aggregates which are present in the other species. Second, small gap junctions are present between the end bulb and spherical cell soma of rats and mice. These interspecies differences are not reflected in thin‐sectioned material. This observation points out the difficulty in attempting to generalize about the significance of intramembrane specializations in synaptic membranes.
Fine structure of regenerated ependyma and spinal cord in Sternarchus albifrons
Authors: Anderson Marilyn J. , Waxman Stephen G. , Laufer Michael 
Published: February 2005

AbstractThe caudal‐most regenerated spinal cord in Sternarchus albifrons consists solely of an ependymal tube. Ependymal cells are enlarged radially and are more numerous than in unregenerated cord. Projections of ependymal cell cytoplasm and Reissner's fiber fill most of the central canal. Small groups of neurites and cell processes filled with dense‐cored vesicles lie between abluminal processes of ependymal cells.Rostral to this, additional cells appear dorsal and lateral to the inner ependymal layer. Some cell bodies contain numerous dense‐cored vesicles. Larger bundles of neurites, some with synapses, are present. Invaginations of the peripheral edge of the cord create enclosed spaces lined with basal lamina. In the peripheral region, longitudinally oriented neurites extend through extracellular spaces or channels. The ventral portion at some levels of regenerated cord is completely filled with neurites, processes containing dense‐cored vesicles, and capillaries. Similar masses of neurites and processes containing dense‐cored vesicles lie outside the cord proper, in or near the meningeal layer.In rostral‐most sections, the organization of regenerated spinal cord approaches that of normal cord, with the regenerated cord exhibiting groups of myelinated axons, differentiated fibrous astrocytes and oligodendroglia, cell bodies containing dense‐cored vesicles, and differentiated electromotor neurons. These observations indicate a degree of pluripotency in some of the ependymal cells in adult Sternarchus. Moreover, they are consistent with a role of ependymal cells in the guidance of regenerating neurites.
Inverse correlation between “Synaptic” ribbon number and the density of adrenergic nerve endings in the pineal gland of various mammals
Authors: Karasek Michal , King Thomas S. , Brokaw James , Hansen John T. , Petterborg Larry J. , Reiter Russel J. 
Published: February 2005

AbstractThe number of “synaptic” ribbons was inversely correlated with the density of the adrenergic nerve endings of the pineal gland compared among a diverse group of species including the fox, cat, rat, cotton rat, white‐footed mouse, Djungarian hamster, ground squirrel, and chipmunk. The concentration of norepinephrine paralleled the number of adrenergic nerve terminals in the pineal glands of the cotton rat, rat, and ground squirrel, the only species in which norepinephrine concentrations were measured. The number of ribbon fields paralleled numbers of “synaptic” ribbons in all species examined. Adrenergic nerve endings were observed primarily within the perivascular spaces, although some endings also were found among parenchymal cells. Adrenergic nerve endings forming synaptic junctions with pinealocytes were not observed in any of these species, nor was there any physical association between these nerve endings and “synaptic” ribbons.
Avian lymph node: Light and electron microscopic study
Authors: Oláh Imre , Glick Bruce 
Published: February 2005

AbstractWe have observed by light and transmission electron microscopy lymphoid accumulations (LA) in the chicken located along the posterior tibial‐popliteal and lower femoral veins. Three types of LA were characterized: (1) LA on the wall of the lymphatic, (2) LA with germinal center, and (3) well‐developed LA possessing germinal centers and an intricate lymphatic sinus system. The latter will be termed a lymph node and is perhaps the structure responding to foot‐pad injection of antigen and/or phytohemagglutinin (PHA). After the injection of PHA into the foot‐pad, the lymph node enlarged and revealed the intermingling of two distinct groups of cells consisting of either small lymphocytes or medium lymphocytes and lymphoblasts. Because our earlier immunological paper proved the presence of T and B cells in the node, the two histologically distinct groups of cells appearing after PHA injection could reflect compartmentalization of T and B cells in the avian lymph node. Lymphoid and adipose tissues are in the same compartment. After PHA or antigen injection into the foot pad, the lymphoid tissue proliferates and the amount of the adipose tissue rapidly decreases. This suggests that lymphoid and adipose tissue form a special complex which is separated from the surrounding tissue by delicate connective tissue capsule. The relationship of the lymphoid and adipose tissue is comparable with that of myeloid and adipose tissue in the bone marrow. The majority of the sinuses shows smooth endothelial lining while others contain “hairy” macrophages attached to the endothelium. The germinal centers are located at the periphery of the node, but a few occur inside. The cellular content of the germinal centers is not unusual except for the presence of plasma cells.
Patterns of X‐radiation‐induced schwann cell development in spinal cords of immature rats
Authors: Gilmore Shirley Ann , Heard Jeanne K. , Leiting Jane E. 
Published: February 2005

AbstractSchwann cells, Schwann cell myelin, and connective tissue components develop in the spinal cord of the immature rat following exposure to x‐rays. For the purposes of this paper, these intraspinal peripheral nervous tissue constituents are referred to as IPNT. A series of investigations are in progress to elucidate factors related to the development of IPNT, and the present study is a light microscopic evaluation of the relationship between the amount of radiation administered (1,000–3,000R) to the lumbosacral spinal cord in 3‐day‐old rats and the incidence and distribution of IPNT at intervals up to 60 days postirradiation (P‐I). The results showed that IPNT was present in only 33% of the rats exposed to 1,000R, whereas its presence was observed in 86% or more of those in the 2,000‐, 2,500‐, and 3,000R groups. The distribution of IPNT was quite limited in the 1,000R group, where it was restricted to the spinal cord‐dorsal root junction and was found in only a few sections within the irradiated area. The distribution was more widespread with increasing amounts of radiation, and IPNT occupied substantial portions of the dorsal funiculi and extended into the dorsal gray matter in the 3,000R group. In all aR mals developing IPNT in the groups receiving 2,000R or more, the IPNT was present in essentially all sections from the irradiated area. Further studies will compare in detail spinal cords exposed to 1,000R in which IPNT is an infrequent, limited occurrence with those exposed to higher doses where IPNT occurs in a more widespread fashion in essentially all animals.
Scanning electron microscopy of monkey foveal photoreceptors
Authors: Borwein Bessie 
Published: February 2005

AbstractRhesus monkey retina and especially the foveal photoreceptors (PR) were investigated by scanning electron microscopy (SEM). There are a few scattered SEM photomicrographs of the primate retina in the literature but this is the first detailed and comprehensive view by SEM of a primate retina. Some new aspects of surface morphologoy are displayed and the study also highlights and emphasizes some aspects of photoreceptor structure that have either been overlooked or not clearly displayed in studies using transmission electron microscopy only.For examination by SEM retinas were fixd in glutaraldehyde‐formaldehyde, osmicated, immersed in thiocarbohydrazide, dehydrated in alcohols, and goldcoted. The fovea appears as a sharply defined pit with steep slopes, and its vitreal surface looks different from that of the rest of the retina. It appears to have a matted surface. The rest of the vitreal surface is relatively smooth and displays distinct lines which diverge in a radiating pattern from the foveal slopes. The chorid has a spongelike appearance; the sclera appears fibrous with the fibers running parallel to the vitreal surface. Photoreceptor nuclei are sometimes lost during tissue processing. They leave a discret “nuclear nest” formed from Müller cell processes. Henle fibers turn at a sharp angle from the cones to run parallel to the vitreal surface. The external limiting membrane is seen as a clear line. Immediately vitreal to it, the Müller cell microvilli surround the proximal inner segments. The cone inner segment (CIS) narrows toward the cilium where the cell is markedly constricted. The ciliary connectives are aligned and appear as a shadwy, slightly wavy zone when the retina is viewed in vertical section. The freestanding, tapering calycal processes (CP) arise from and are continuous with longitudinal CIS ridges. CP surround the proximal parts of the outer segments (OS), but there are no CP around the ciliary backbone. Some CP bear small protrusions. OS break off and remain embedded among the pigment epithelium microvilli (PEM) more often than PEM remain attached to OS distal ends. The foveal OS tapers slightly from its proximal to its distal end. The OS may bear knoblike swellings and convolutions in their more distal regions but not at their tips.