bluuebunny/crossref_metadata_2025 huggingface dataset:
Trophic effect of the sympathetic nervous system on the early development of the rat parotid gland: A quantitative ultrastructural study
Authors: Bloom Gunnar D. , Carlsöö Bengt , Danielsson Åke , Hellström Sten , Henriksson Roger
Published: February 2005

Rats were sympathetically denervated on one side by avulsion of the superior cervical ganglion either immediately after birth (within 4 hr) or when the salivary glands were fully developed. Nine weeks after ganglionectomy the parotid glands were subjected to microscopical studies. As shown by the lack of specific fluorescence, sympathetic denervation caused an almost total depletion of catecholamines in the acini. This was further substantiated at the electron microscopic level using KMnO4 as fixative. No alterations in either gland weight or in acinar cell size were noticeable after adult sympathectomy. On the other hand, neonatal denervation caused a decrease in gland weight as well as acinar cell hypotrophy. The mean volume of individual acinar cells was reduced by roughly 25% and the granule volume density by about 50%. Also the mean volume of individual granules was decreased. These findings indicate an important role for the sympathetic nerve system in the maturation of the rat parotid gland.
Ultrastructural changes during stimulation of amphibian oxyntic cells viewed by scanning and transmission electron microscopy
Authors: Logsdon Craig D. , Machen Terry E.
Published: February 2005

Amphibian oxyntic cells exposed by cryofracture were examined by field emission scanning electron microscopy. Comparisons were made between the structure thus revealed and those seen in thin‐sectioned material from the same mucosas examined by transmission electron microscopy. Resting oxyntic cells had apical surfaces which were relatively smooth with some short microvilli. Apical cytoplasm was filled with smooth membrane tubules (so‐called vesicotubules). Stimulation with a combination of histamine, dibutyryl cyclic AMP, and isobutylmethylxanthine (a phosphodiesterase inhibitor) led to a dramatic elaboration (i.e., increased membrane surface area) and a decrease in number of vesicotubules in the apical cytoplasm. The surface morphology of the stimulated oxyntic cell was much different from that reported for the mammalian parietal cell. Two types of surface elaboration were observed. Most commonly the surface was formed of flattened microplicae or lingulae. An irregular surface formed by the swelling of enlarged spaces near the apical surface was also observed. These new data have been used to evaluate the models which have been proposed to explain the nature of the transition from resting to stimulated morphology. A new model, which incorporates fusion of intracellular vesicotubules with each other and also with apical membrane, is proposed. The proposed fusion process may cause an increase in membrane area open to the extracellular (luminal) solution within the cell (rather than the eversion of membranes into the gastric lumen). Expansion of spaces between the microplicae may be caused by hydroosmotic pressures developed during active HCl secretion.
Organ distribution and fate of newly formed splenic lymphocytes in the pig
Authors: Pabst R. , Nowara E.
Published: February 2005

The production of lymphoid cells in the pig spleen was studied autoradiographically after selective labeling of the spleen using an extracorporeal perfusion circuit. Tritiated thymidine was added as a DNA precursor. One to 4 days after local labeling of the spleen the relative and absolute number of spleenderived lymphocytes were determined in the following organs: mesenteric, cervical and inguinal lymph nodes, thymus, bone marrow, Peyer's patches, tonsils, three different parts of the gut, lung, liver, and blood. The labeled lymphocytes which migrated to these organs were all small lymphocytes, except for some large cells in the lamina propria. In the bone marrow, however, a considerable number of the spleen‐derived immigrants were transformed into plasma cells. The total number of labeled lymphocytes decreased dramatically from Day 1 to Day 4 after labeling, indicating a high percentage of short‐lived cells. Within the spleen, plasma cells had the highest labeling index of about 30% at Day 1 but this dropped to only 1.5% on Day 3. The organ distribution of the splenic emigrants changed from Day 1 to Day 4 with a relative increase in lymphocytes found in lymph nodes and a decrease in the lung and the intestinal wall. The newly formed splenic lymphocytes migrated to T‐ and B‐cell areas in lymph nodes, Peyer's patches, and tonsils. In the intestinal wall labeled lymphocytes were found in the lamina propria and also as intraepithelial lymphocytes. There was no obvious redistribution between organ compartments with time after labeling of the spleen. The spleen produces large numbers of lymphocytes, which show typical organ distribution and homing to areas in lymphoid and nonlymphoid organs.
Axoglial synaptoid contacts in the neural lobe of the human fetus
Authors: Okado Nobuo , Yokota Norio
Published: February 2005

Axoglial synaptoid contacts as well as junctional specializations were examined in the neural lobe of five human fetuses ranging from 7.5 to 19 weeks of ovulation age. Because synapselike contacts (SLC), which have both presynaptic and postsynaptic densities, were observed only in the youngest fetus (7.5 weeks), they may be transient structures. Axoglial SLC were also found in older fetuses, but their structural characteristics were different from those found in a 7.5‐week fetus in that the cytoplasmic membrane density was found only on the presynaptic side and its extent was decreased.

In the youngest fetus observed here (7.5 weeks), puncta adherentia were observed. In the fetuses older than 11 weeks, gap junctions, long adherentia‐type junctions with thick filamentous structures, and mixed junctions with both types of contact were found between pituicytes.
The ability to predict weight gain, individual organ weight, and corresponding food intake in the rat by the four‐parameter model for physiological responses
Authors: Schweisthal Michael R. , Cole Thomas B. , Mercer L. Preston
Published: February 2005

The applicability of the four‐parameter model for physiological responses to the prediction of food intake and corresponding weight gain and individual organ weight gain was studied further in 40‐day postpartum male rats. Seven groups of animals were maintained on diets in which protein content ranged from 0 to 23.54% casein. Food intake and weight gain were recorded every other day for each animal for 21 days. At the termination of the experiment the following organs were removed and weighed: liver, heart, lungs, spleen, kidneys, adrenals, and testes. When these weight values are fitted by use of the four‐parameter model, food intake and total animal and organ weight gains can be predicted in relation to the amount of protein in the diet. It was found that liver, heart, lungs, spleen, and whole animal had similar K(0.5) values. However, it was also shown that there is variation in response of organs when relating organ weight as a percentage of body weight. For example, heart, lungs, and testes show an increased ratio on low protein diet while liver, kidneys, and adrenals maintain a fairly constant ratio and the spleen shows a decreased ratio. Additionally, it was noted that the animals on low protein diet consumed more food per gram body weight but did so at a slower rate. Possible future applications of the four‐parameter model for physiological reponses are discussed.
Correlation between growth rate and cytochemistry in morris hepatomas
Authors: Kang Yuan‐Hsu , Morris Harold P. , Criss Wayne E.
Published: February 2005

The correlation between the cytochemistry (glycoprotein, glycogen, glucose‐6‐phosphatase, catalase, alkaline phosphatase) and the growth rate of the fast‐growing Morris hepatoma 3924A and the slow‐growing Morris hepatoma 9618A was studied by utracytochemical techniques.

By the chromic acid‐phosphotungstic acid technique, acid glycoprotein is stained in glycocalyx, Golgi saccules and vesicles, and secretory granules of the tumor cells of both hepatomas. However, the hepatoma 3924A cells contain thicker glycocalyx and more numerous glycoprotein‐rich granules than hepatoma 9618A cells. Abundant alpha and beta glycogen particles are present in the hepatoma 9618A cells, whereas extremely few beta particles are found in hepatoma 3924A. Moderate glucose‐6‐phosphatase activity is observed in the cisternae of endoplasmic reticulum and nuclear envelope of hepatoma 9618A, but it is totally absent in hepatoma 3924A. High catalase activity is present in numerous peroxisomes of hepatoma 9618A. Hepatoma 3924A contains only a few catalase‐positive microperoxisomes. Weak to moderate alkaline phosphatase is present in the plasma membrane and nuclear envelope of hepatoma 9618A cells, while hepatoma 3924A shows no activity of the enzyme. All the cytochemical parameters except glycoprotein show an inverse relationship with the growth rate of the hepatomas. The higher intracellular glycoprotein content of hepatoma 3924A may be related to differences in cell coat secretion (composition and activity) from the slower‐growing hepatoma 9618A.
Sperm autoantigens and fertilization. III. Ultrastructural localization of guinea pig autoantigens
Authors: Tung Kenneth S. K. , Yanagimachi Hiroko , Yanagimachi Ryuzo
Published: February 2005

Guinea pig sperm autoantigens have been localized by direct and indirect immunoferritin techniques in (1) plasma membrane over the entire sperm head, (2) acrosomal contents, (3) fibrous sheath and outer dense fibers of the tail filament, and (4) the inner acrosomal membrane of 50% of acrosome reacted spermatozoa. These cellular structures are known to be involved in guinea pig sperm rouleaux formation, acrosome reaction, interaction of acrosome‐reacted sperm with zona pellucida and with the vitellus of guinea pig ova. Since IgG and Fab of autoantiserum to guinea pig spermatozoa have been shown to interfere with these cellular reactions, this study provides further evidence, albeit indirect, that sperm autoantigens are involved in these cellular events.
Parabiosed rabbit ears: An innovation for experimental subcutaneous implantation
Authors: Grimes L. Nichols
Published: February 2005

A new technique is described for the experimental implantation of material subcutaneously into the rabbit ear's auricula without having to cut the skin at the surface of the site. This technique is important because the integument's vascular suppy to the implantation site is not severed as it is with other implantation techniques. The techique consists of resecting all the tissue except one integument from a circular site on each of the rabbit's auriculae. Then the two auriculae are parabiosed at these sites with the implant inserted between them.
Acid and alkaline phosphatase activity in migrating primordial germ cells of the early chick embryo
Authors: Swartz William J.
Published: February 2005

Little information is available concerning enzyme activity in primordial germ cells (PGCs) of the early chick embryo. The present study is designed to examine the disposition of alkaline and acid phosphatase activity in the PGCs during their migration into the developing gonads of the early chick embryo. White Leghorn chick embryos were sacrificed at daily intervals from 1 to 6 days of incubation. Following sacrifice the embryos were fixed, dehydrated, and embedded in glycol methacrylate (GMA). Alkaline and acid phosphatases were demonstrated by the simultaneous diazo‐coupling method. The embryonic tissues at the different ages were examined for PGCs and the histochemical reactions for alkaline and acid phosphatases in these cells evaluated. Acid phosphatase activity did not appear within PGCs until 3 days of incubation, and then in only a few PGCs in the active phase of their migration in the dorsal mesentery, suggesting that there is no large wave of degeneration of these cells during migration. Alkaline phosphatase activity was observed as early as 2 days of incubation in PGCs during the passive phase of their migration in extraembryonic blood vessels. Alkaline phosphatase‐positive PGCs in the active phase of migration were also found in the dorsal mesentery; however, the cellular localization of this enzyme differed from that observed in the passively migrating PGCs, indicating that there are alterations in the metabolic activities of these cells during the active and passive phases of migration.
Cell specialization in collecting tubules of the guinea pig kidney: Carbonic anhydrase activity and glycosaminoglycan production in different cells
Authors: Sato Akira , Spicer Samuel S.
Published: February 2005

The distribution of complex carbohydrates has been investigated cytochemically at the light and electron microscope levels in collecting ducts of the guinea pig kidney. The dialyzed iron method demonstrated acidic complex carbohydrate ultrastructurally on the outer surface of the apical and the basolateral plasmalemma of the principal cells and in their maturing Golgi cisternae and secretory granules. Glycoconjugate in these sites stained for sulfate esters with the high iron diamine method but lacked reactivity toward the periodic acid‐thiocarbohydrazide‐silver proteinate (PA‐T‐SP) sequence for visualizing vicglycol‐containing glycoprotein. Lability to testicular hyaluronidase and resistance to sialidase identified the Glycosaminoglycan (GAG) in principal cell granules and the plasmalemmae as a chondroitin sulfate. In contrast, intercalated cells of the collecting ducts failed to stain with the cationic reagents, but showed light PA‐T‐SP reactivity demonstrative of neutral glycoprotein in the glycocalyx of the apical plasmalemma. Immunostaining with the immunoglobulin‐enzyme bridge procedure localized carbonic anhydrase selectively to the intercalated cells. The ultrastructural and cytochemical observations on the guinea pig collecting ducts implicate intercalated cells in fluid and electrolyte transport and principal cells in secretion of a chondroitin sulfate to the tubule lumen and intercellular space.
Ultrastructural localization of alkaline and acid phosphatases in the human fallopian tube epithelium during the menstrual cycle
Authors: Lindenbaum Ella S. , Beach Dvorah , Peretz Bezalel A.
Published: February 2005

Ultrastructural and cytochemical methods were utilized to study the human Fallopian tube fimbrial epithelium during the different stages of the menstrual cycle.

Alkaline phosphatase reaction product was located along the apical and lateral plasma membranes of the secretory cells only, regardless of the stage of the cycle. The ciliated cells were almost devoid of any reaction product at all stages of the cycle.

Acid phosphatase reaction product depicted the lysosomes. These appeared as electron‐dense bodies, of almost equal numbers in the ciliated and the secretory cells at all stages of the cycle. Thus the number of lysosomes did not vary appreciably during the different stages of the menstrual cycle. Many lipid droplets were found in both cells; these were rimmed by acid phosphatase reaction product, and some were partially enveloped by electron‐dense bodies containing acid phosphatase deposits. Acid phosphatase deposits were also found on the inner face of Golgi vesicles.
Morphometric changes in the lungs of rats following adrenalectomy supplemented by desiccated thyroid
Authors: Adkisson V. T. , Callas G.
Published: February 2005

Studies were conducted to assess the effects of thyrotoxicosis on the lung of the adult adrenalectomized rat. The animals were divided into four groups of seven animals each: Adrenalectomized animals receiving desiccated thyroid in their food for 8 weeks, adrenalectomized animals, and sham‐operated animals receiving regular laboratory chow. Unoperated animals were used as controls. There were no differences in the pressure‐volume curves or morphometric parameters between unoperated‐control and sham‐operated animals; therefore they will be collectively reported as control animals. Lung volume in the thyroid‐treated animals showed an increase of 19% in pressure‐volume studies when compared with the other groups. Lung volume determined morphometrically demonstrated a 19% increase in volume when adrenalectomized thyroid‐treated rats were compared with control amimals, and a 29% increase compared with adrenalectomized animals. The thyroid‐treated animals also showed an alveolar surface density (Sva) increase of 58% over control and 28% over adrenalectomized animals. In addition, alveolar surface area (Sa) of the treated animals was 89% greater than control and 65% greater than adrenalectomized animals. The marked difference in the surface‐to‐volume ratio indicates that alveoli were smaller and more numerous in the lungs from the thyroid‐treated animals. These results are readily apparent in examination of light microscopic sections of the lung specimens from the four groups of animals. These findings indicate that chronic thyroid administration results in a significant increase in lung volume, which we attribute to increased alveolar partitioning.
Continuous‐Perifusion tissue culture of fetal and adult pancreas of the lizard Anolis carolinensis
Authors: Rhoten William B.
Published: February 2005

The 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

The 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

Proliferation 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

A 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

Pancreatic 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

The 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

We 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

This 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

Weekly 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

Stereological 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

Two 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

The 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

The 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

We 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

Schwann 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

Rhesus 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.
Autoradiographic location of sensory nerve endings in dentin of monkey teeth
Authors: Byers Margaret R. , Dong Willie K.
Published: February 2005

We have used the autoradiographic method to locate trigeminal nerve endings in monkey teeth. The nerve endings were labeled in two adult female Macaca fascicularis by 20 hours of axonal transport of radioactive protein (3H‐L‐proline). We found a few labeled axons in contralateral mandibular central incisors and one mandibular canine. In ipsilateral teeth, numerous myelinated and unmyelinated axons were labeled; they formed a few terminal branches in the roots but primarily branched in the crown to form the peripheral plexus of Raschkow and to terminate as free endings in the odontoblast layer, predentin, and as far as 120 μm into dentinal tubules. Electron microscopic autoradiography showed that the radioactive axonally transported protein was confined to sensory axons and endings; odontoblasts and dentin matrix were not significantly labeled. Labeled free nerve endings were closely apposed to odontoblasts in dentin but did not form distinctive junctions with them.

Nerve endings were most numerous in the regular tubular dentin of the crown adjacent to the tip of the pulp horn, occurring in at least half of the dentinal tubules there. Reparative dentin was poorly innervated, even near the tip of the crown, and it had a different tubular structure and adjacent pulpal structure from the innervated dentin. Radicular dentin was not innervated in most areas but did contain a few labeled axons where the predentin was wide and the odontoblasts were columnar, as at the buccal and lingual poles of some roots.

Our results show that dentinal sensory nerve endings in primate teeth can be profuse, sparse, or absent depending on the location and structure of dentin and its adjacent pulp. When dentin was innervated, the tubules were straight and contained odontoblast processes, the predentin was wide, the odontoblast cell bodies were relatively columnar, and there was an adjacent cell‐free zone and pulpal nerve plexus.
Silver methods applied to semithin sections to identify peptide‐producing endocrine cells
Authors: López J. , De Rada O. Díaz , Sesma P. , Vázquez J. J.
Published: February 2005

Silver methods were successfully applied to semithin sections of Epon‐embedded material, in bronchial epithelium of the chicken lung, as well as in stomach and gut of the frog. Silver methods with some modifications characterize very well the cytoplasmic argyrophilic and argentaffin granules. They give good results in plastic‐embedded material.
A new look at the mineralized and unmineralized components of intraosseous fibers of the interdental bone of the mouse
Authors: Johnson Roger B.
Published: February 2005

The degree of mineralization of deeply embedded intraosseous fibers has been the subject of speculation. However, there were few available descriptive morphological studies addressing this question. The present study demonstrated that morphological differences were evident between intraoseous fibers of different levels of the interdental septum. It also revealed that the degree of mineralization of intraosseous fibers was often different at the wall of the tooth socket in comparsion to that at deeper levels of interdental bone. Except in the superior crestal third, intraosseous fibers became less mineralized as they passed from the wall of the tooth socket to the midline of the interdental septum. They were surrounded by sheaths throughout their distribution. It was concluded that there might be significant differences in the morphology of intraossoeus fibers of the mouse in comparision to the morphology of intrasseous fibers of the dog, which have previously been described in detail.
A granular cell at the acinar‐intercalated duct junction of the rat submandibular gland
Authors: Qwarnström E. E. , Hand A. R.
Published: February 2005

A granular cell was present at the acinar‐intercalated duct junction in submandibular gland of adult rats of several different strains. It occurred more frequently in females thanin males. It was a small pyramidalshaped cell, usually forming the most proximal part of the intralobular duct system. The cell contained a relatively large, basally located nucleus. Numerous heterogeneous granules, usually exhibiting both electron‐dense and electron‐lucent regions, were present in the apical cytoplasm. Exocytosis of the granules at the apical cell surface was occasionally seen. Dilated cisternae of endoplasmic reticulum were frequently observed between the apical granules and in the basal and lateral cytoplasm. The function of the granular cell is unknown. Their structure and location suggest that they may (1) constitute a mature secretory cell population, or (2) represent progenitor cells for acinar and/or intercalated duct cells.
Ultrastructural and biochemical changes in rat soleus muscle following tenotomy
Authors: Margolis Ronald N. , Baker James H.
Published: February 2005

This study was designed to correlate changes in the ratelimiting enzymes of glycogen synthesis (glycogen synthase) and glycogen breakdown (glycogen phosphorylase) with the ultrastructural changes which occur in the soleus muscle following tenotomy. Soleus muscles were removed at 1, 2, 3, 7, 14, 21, and 63 days after tenotomy and were prepared for electron microscopy or frozen for enzyme analysis. In the first 7 days posttenotomy, soleus muscle fibers underwent a series of degenerative changes, while both synthase and phosphorylase activities decreased. Over the next 8 weeks the histological appearance of the soleus muscle eventually returned to normal while synthase and phosphorylase activities increased. We suggest that recovery from tenotomy involves an increase in the energy demands of the muscle, resulting in the increased activity of the key rate‐limiting enzymes of muscle glycogen metabolism from the drastically reduced levels observed in the period before recovery begins.
Effect of ethanol on nucleolar structure: A cytological indication of change in RNA/protein synthesis
Authors: Dunmire Carole R. , Lavelle Faith W.
Published: February 2005

The effects of chronic ethanol ingestion on an organelle known to be involved in protein synthesis were studied cytologically in nerve cells of the adult hamster. Twenty‐six animals were administered standard laboratory chow and either tap water (controls) or a 15% ethanol solution (experimentals) for a period of 7 weeks. Brains were perfusion‐fixed, sectioned transversely, and stained with buffered thionin for microscopic analysis. Reported here are changes in an RNA‐rich intranucleolar body (INB) seen in facial motor neurons and cerebellar Purkinje cells of the golden hamster. After chronic ethanol ingestion, the size and frequency of the INB increased significantly in both cell populations. Theoretical considerations are discussed concerning the correlation between this apparent storing of nucleolar RNA/RNP and the biochemical evidence of other investigators for ethanol‐induced alterations in RNA/protein synthesis and utilization in neurons.