bluuebunny/crossref_metadata_2025 huggingface dataset:
The ultrastructure of adrenergic neurons in sympathetic ganglia of the newborn rabbit after treatment with 6‐hydroxydopamine
Authors: Papka Raymond E.
Published: February 2005

The effects of 6‐hydroxydopamine, an analog of dopamine which produces degeneration of peripheral adrenergic nerve terminals in adult animals, on adrenergic neurons in the sympathetic ganglia of newborn rabbits were studied with the electron microscope. Animals were treated with a 50 mg/kg dose of 6‐hydroxydopamine within six hours after birth and subsequently given daily doses until seven injections had been administered. The results of this study indicate that the adrenergic neurons underwent a “reaction” to 6‐hydroxydopamine which was first manifested by an increase in filaments and smooth membranous structures in the cell bodies. In the axons of these neurons a similar increase in filaments and membranous elements, as well as accumulations of dark‐core vesicles and mitchondria, were evident. Microtubules, although plentiful in normal cells and axons, were not conspicuous in these cells and axons. This initial reaction was later followed by degeneration of the cell bodies and axons and their eventual disappearance, leading to a reduction in cell population and size of the ganglia. It is suggested that the initial effect of 6‐hydroxydopamine on adrenergic neurons (in newborn animals) may be an interference with their axoplasmic transport mechanism which leads to cell degeneration and death. This study also has shown that some of the small “granule‐containing” cells in sympathetic ganglia may be sensitive to 6‐hydroxydopamine, at least in newborn rabbits, as is indicated by their degeneration.
Intestinal absorption of ferritin in the suckling rat
Authors: Shervey Paul D. , Gardner Paul J.
Published: February 2005

Extensive absorption of ferritin was demonstrated in the proximal and distal ileum of 8–12 day‐old rats. In some regions, ferritin droplets were distributed in the basal cytoplasm of the columnar epithelium and in the lamina propria one hour after feeding. Subsequently, iron‐positive material was localized adjacent to vessels of the lamina propria and in macrophages. Absorption of lesser quantities was demonstrated in the duodenum.
Thymus weight changes during the early post‐natal period in mice
Authors: O. Simpson Leslie
Published: February 2005

Multiple regression analysis of the relationships of thymus weight to age and body weight, suggests that thymic growth patterns are widely variable and possibly are strain characteristics.
Location of nerve cells producing the synaptic vesicles situated in the substantia gelatinosa of the spinal cord (1)
Authors: Duncan Donald , Morales Ricardo
Published: February 2005

A search for the cells of origin of synaptic vesicles with electron‐opaque cores and located in the substantia gelatinosa was attempted by subjecting cats to transection of dorsal roots and double hemisection in the upper lumbar region. The hemisections were accompanied by interruption of the dorsal rootlets to the affected segment. The cats were perfused with buffered aldehydes and processed for electron microscopy 55–71 days after the operations. Comparison of intact and operated sides of the rhizotomized cats revealed no discernible differences in numbers and location of the granulated vesicles associated with the substantia gelatinosa. In cats with double hemi‐section plus rhizotomy the distribution of the granules was the same on the normal and operated sides but the numbers appeared to be reduced especially close to the surgical incisions. Dark‐core vesicles were situated in association with the Golgi apparatus of substantia gelatinosa neurons, in dendrites, in small axons and in synaptic sacs in all material studied. It was concluded that most of the granulated vesicles located in the substantia gelatinosa are produced by small neurons in the immediate vicinity of their axon terminals.
Radioimmunological evidence for early functional activity in chick embryonic beta cells
Authors: Green Tim D. , Benzo Camillo A.
Published: February 2005

A radioimmunoassay for insulin was utilized to investigate developmental aspects of insulin storage and secretion in the chick embryo. Immunoreactive insulin was detected in both the pancreas and blood plasma from the fifth embryonic day onwards. The present data show that the chick embryonic beta cell has the potential for activity early in development, and that insulin may be secreted at earlier developmental stages than hitherto accepted.
Fine structural studies of the sino‐auricular nodal tissue in the heart of a teleost fish, misgurnus, with particular reference to the cardiac internuncial cell
Authors: Yamauchi Akio , Fujimaki Yoko , Yokota Reiko
Published: February 2005

The sino‐auricular nodal tissue of the heart of the loach (Misgurnus anguillicaudatus, Cantor) contains (1) myocardial cells receiving rich innervation, (2) isolated nerve cells, and (3) cardiac internuncial cells which are interposed between autonomic axon terminals and myocardial cells. Structural specializations are noted at the synapse between the autonomic axon and the myocardial cell, as well as at the axon‐internuncial cell synapse. Between the internuncial cell and the myocardial cell, attachment plaques are present with a patchy locus of a close junction, wherein the extracellular space appears to be almost obliterated. Estimations were made of the surface areas of an internuncial cell body and a nerve cell body as revealed by serial sampling of the tissue at about 0.5 μ intervals. The results show that for an internuncial cell body followed over a length of 15 μ, 52.5% of its total surface is covered by vesiculated axons, 3.8% by non‐vesiculated axons, 12.2% by myocardial cells, and 3.1% by Schwann cell processes; for a nerve cell body followed over a length of 16 μ, only 1.8% is covered by vesiculated axons, 0.5% by non‐vesiculated axons, nil by myocardial cells, and 96.4% by a satellite cell and its processes. It is considered that the internuncial cell represents a specialized cell type in the nodal tissue of the fish heart, playing a role in modulating the autonomic nerve impulses before they are transmitted to the effector myocardial cells.
Large inclusions in receptor cells of the amphibian lateral line
Authors: Wickham M. Gary
Published: February 2005

With few exceptions, anatomical studies of amphibian lateral line systems have been limited to gross and light microscopic investigations. The lateral line of Xenopus laevis had been studied at the fine structural level, but electron microscopic data are available only for late larval and adult stages. A comparison of the ultrastructure of lateral line receptor cells at different stages in the life histories of urodele species indicates that four categories of large (to 3 μ diameter) organelles occur in these animals. Apical and synaptic dense bodies are morphologically similar but lie at opposite ends of the cell. Lysosomes and multivesicular bodies are concentrated in regions of the Golgi apparatus. Previously undescribed perinuclear crystalline inclusions seem to be associated with bundles of microfilaments. Inclusions of similar internal structure also occur within the nucleus. The location of a crystalline structure in the nucleus makes the definition of a more typical nucleolus mandatory.
Emiocytosis of B granules from saurian pancreatic islets perifused in vitro
Authors: Rhoten William B.
Published: February 2005

Splenic islets of Anolis carolinensis incubated in an in vitro perifusion system with media containing a non‐stimulatory concentration of glucose had the same ultrastructural appearance as islets removed from an intact animal. When horseradish peroxidase was included in this medium, no profiles suggestive of emiocytotic release of B granules were observed despite basal insulin secretion.

With cytochalasin B and a high concentration of glucose, the B cells exhibited margination of their secretory granules and moderate degranulation, but rarely were profiles suggestive of emiocytosis seen. In the presence of cytochalasin B, glucose and the other insulin secretagogues used, the B cells were more degranulated than with only cytochalasin B and glucose present, but profiles indicative of emiocytosis were infrequently encountered. Emiocytosis of the B granules was demostrated convincingly with the inclusion of peroxidase and the above agents. Virtually all the B cells had at least one secretory granule fused with the limiting membrane and surrounded by the peroxidase, and some B cells exhibited multiple release of granules. From these observations it is concluded that emiocytosis plays a major role in the secretion of insulin from B cells of Anolis.

The B cells from control perifusions, as well as from intact animals, did not contain a microfilamentous cell web. Granular or filamentous masses were not demonstrated in B cells from splenic islets perifused with cytochalasin B. The mechanism of emiocytotic release of insulin from the B cells of Anolis is discussed with reference to these observations.
Uptake of marker particles by in vitro ventilated and perfused rat lung
Authors: Vidić Branislav
Published: February 2005

Colloidal gold marker was present in the capillary lumen and at various stages of pinocytosis and passage through the endothelial cells. It was occasionally located in the peri‐endothelial space, close to the basement membrane. The uptake of marker by other cells was not observed. These results suggest the existence of two barriers, the biological (pinocytotic and hydrolytic capacities of the endothelial cells) and mechanical (permeability of the basement membrane).
Morphometry of synaptic ultrastructure using equidensitometry
Authors: Nolan Terence , Jones D. Gareth
Published: February 2005

Electron micrographs of synapses stained with an ethanolic solution of phosphotungstic acid have been subjected to equidensitometric analysis by the recently developed Agfacontour Professional film. Subtle variations in the staining of presynaptic dense projections and postsynaptic structures have been detected. Morphometry of these micrographs has been facilitated by this technique which is rapid and obviates the need for expensive and complex electronic equipment.
Morphology of the nasal cavities and associated structures in Artibeus jamaicensis and Myotis lucifugus
Authors: Bhatnagar Kunwar P. , Kallen Frank C.
Published: February 2005

Anatomical differences in olfactory structures point to a more highly developed olfactory sense in the frugivorous bat Artibeus jamaicensis than in the insectivorous bat Myotis lucifugus. Artibeus' nostrils show greater potential for differential control of nasal airstreams. Its nasal cavities, in contrast to Myotis, are clearly demarcated into olfactory and respiratory portions. Both species have seven turbinals, but of the five ethmoturbinals, Artibeus has four endoturbinals and one ectoturbinal whereas Myotis has three and two, respectively. The configuration and histology of the more complex turbinals of Artibeus indicates a greater surface area of olfactory epithelium. The nasal epithelia are thicker in Artibeus. Olfactory receptors appear similar in both species but the thickness and composition of the olfactory epithelium in Artibeus suggests the presence of about twice as many receptors per unit area. This is also reflected in the relative prominence of olfactory nerve bundles. From these and other bulbar relationships we conclude that the proportion of fila olfactoria to large mitral cells, as reflected by the olfactory bulb glomeruli, is some function of a fundamental 2:1 relationship. Nasal glands, with flaps covering two of their more prominent ducts, and blood vessels are more pronounced in Artibeus. This presumably correlates with the nasal type of phonation exhibited by this bat as well as a greater ability to condition air per se. Nasopalatine ducts exist in both species but only Artibeus has a vomeronasal organ. A diffuse ganglion accompanies the organ; some of its neurons are associated with the unmyelinated vomeronasal nerve, whereas others are intraepithelial. The vomeronasal nerve terminates in a prominent accessory olfactory bulb.
Coexistence of dyads and triads in an adult striated muscle
Authors: Wong Y. C. , Hwang J. C.
Published: February 2005

Electron microscopic studies have revealed the presence of both dyads and triads in the accessory muscle of the walking leg of the horseshoe crab Tachypleus gigas. The dyads and triads are present in approximately equal numbers. The evolutionary significance of the coexistence of dyads and triads in such an ancient animal is discussed.
Quantitative electron microscopic autoradiography of in vivo incorporation of 3H‐choline, 3H‐leucine, 3H‐acetate and 3H‐galactose in non‐ciliated bronchiolar (Clara) cells of mice
Authors: Petrik Peter , Collet André J.
Published: February 2005

The participation of Clara cells in the formation of alveolar surfactant and their general metabolism were studied in mice by quantitative autoradiography under electron microscopy after in vivo incorporation of four precursors: 3H‐choline, 3H‐leucine, 3H‐acetate and 3H‐galactose.

Tritiated choline, a specific precursor of the dipalmitoyl‐phosphatidylcholine‐active fraction of the surfactant, is not incorporated into Clara cells. In contrast, 3H‐acetate is first incorporated actively into the endoplasmic reticulum and Golgi apparatus of these cells and, subsequently, in its secretory granules. It is suggested that acetate follows the general metabolism of the cell and/or is transformed into cholesterol. Tritiated leucine is incorporated into the secretory granules, although part of it remains more permanently in the cells. Tritiated galactose is actively incorporated, passes through the Golgi apparatus and eventually appears in the secretory granules.

These results suggest that the Clara cell does not synthetize the tensio‐active fraction of the lining layer, as does pneumocyte II, but participates in the synthesis and secretion of proteins, glucides and possibly the cholesterol belonging to the hypophase.
Regeneration of the ureter and repair of the oviduct in the adult newt Notophthalmus viridescens
Authors: Scadding Steven R. , Liversage Richard A.
Published: February 2005

The responses of the oviduct and the male ureter to transection were studied histologically. The ureter regenerates by the formation of a blastema, then the development of a bridge of cells between the cut ends, and finally by restoration of the lumen. Seven out of 12 cases fixed 30 to 40 days after transection had reconstituted the lumen and four of the remaining five cases had the two ends joined and would likely have regenerated if they had not been fixed. In contrast, the oviducts did not appear to have any regenerative capacity; only two out of the 17 cases fixed 31 to 41 days after transection exhibited some reconstitution. The transected oviducts did not form a blastema or give any evidence of cellular dedifferentiation.
Ultrastructure of the mouse superior cervical ganglion, with particular reference to the pre‐ and postganglionic elements covering the soma of its principal neurons
Authors: Yokota Reiko , Yamauchi Akio
Published: February 2005

Electron microscopy of superior cervical ganglia of the mouse shows both pre‐ and postganglionic elements impinging upon the soma of principal neurons. The preganglionic cholinergic axon terminals are estimated to cover about 0.7% of the total surface area of the neuronal soma and are characterized by dense packing of synaptic vesicles which remain unchanged after the administration of 5‐hydroxydopamine. Postganglionic elements are estimated to cover about 1.8% of the total surface of the neuronal soma. In many cases they contain small granular vesicles (with or without agranular reticulum), and are considered to be represented in part by vesiculated segments of the dendrite and in part by recurrent axon collaterals of the principal neuron. These postganglionic elements usually make puncta adhaerentes, but occasionally an efferent synapse, on the soma of principal neurons in the ganglion. Evidence is presented which suggests that the soma, in turn, is capable of influencing the perisomal, postganglionic elements through a somatic efferent synapse.
Increased orbital volume after periodic intrabulbar injections of silicone in growing rabbits
Authors: Sarnat Bernard G. , Shanedling Philip D.
Published: February 2005

The intent of this experiment was to determine whether with an increase in ocular mass there would be an increase in orbital volume. Eighteen, four‐week old, 220 to 420 gm Dutch rabbits were used. In 12 animals silicone was injected into one eye but not the opposite one. No silicone was injected into the eyes of six untreated rabbits. In a ten week period the total amount of ten silicone injections into each treated eye ranged from 1.2 to 1.6 ml. After each rabbit was euthanatized, elastic rubber base imprints were made of both cleaned orbits to determine the volumes. In the untreated animals the differences between the right and left orbital volumes ranged from — 0.1 to 0.2 ml (— 2.4 to 4.7%). The mean of the differences was not statistically significant. When the eyes were injected with silicone, the differences in orbital volumes between the injected and non‐injected sides ranged from 0.6 to 0 ml (14.6 to 0%). The mean of the differences was 0.3 ml which is statistically significant. It was concluded that periodic intrabulbar injections of silicone in the growing rabbit significantly increased orbital volume.
Some observations on the fine structure of the epidermal‐dermal junction in the skin of the frog tadpole, Rana rugosa
Authors: Nakao Taisuke
Published: February 2005

Special lamellated bodies, 400 to 700 Å in diameter, are observed in the adepidermal space at the epidermal‐dermal junction of the skin of the frog tadpole, Rana rugosa. Each stained lamella is about 20 Å thick and separated from adjacent lamellae by spacings of 20 to 30 Å. The lamellated bodies are demonstrated in specimens prepared with phosphotungstic acid (PTA)‐containing fixatives, but are not revealed in specimens fixed with ordinary aldehyde fixatives which lack PTA. They are sometimes observed within the cytoplasm of basal epidermal cells, suggesting their epidermal origin. Far less frequently, comparable structures are present outside the sarcolemma of skeletal muscle fibers. Three kinds of anchoring structures are observed at the epidermal‐dermal junction: anchoring filaments, anchoring fibrils, and anchoring fibers. The anchoring filaments are observed in the adepidermal space connecting hemidesmosomes to the basal lamina. They are 200 to 230 Å in diameter and have no banding pattern. Anchoring fibrils, 210 to 250 Å thick and unbanded, are present in the upper one‐third of the collagenous lamellae. Fibrils do not have a banding pattern. Direct continuity between anchoring fibrils and anchoring filaments is suggested. Anchoring fibers, about 170 mμ, thick, occur less frequently. They are composed of laterally aggregated finer fibrils which show no clear bandings. Their distal ends join with the basal lamina and they extend proximally deep into the collagenous lamellae.
Distribution and configuration of surface myoneural junctions in the frog sartorius muscle
Authors: Carpenter Duncan B.
Published: February 2005

The Karnovsky cholinesterase stain was used to map the positions of the myoneural junctions distributed over the inner surface of three frog sartorius muscles. In each preparation end‐plates were seen to occur in clusters, predominantly associated with fine myelinated nerve fibers in proximity to the larger nerve branches. No myoneural junctions were observed in the extreme proximal or distal regions of the muscles. Although more junctions were found in the regions proximal to the point of nerve entry into the sartorius muscle, terminals were more consistent in their location in areas distal to this point. End‐plate configurations varied appreciably in length, branching and complexity, but the majority of the terminal nerve processes extended parallel to the long axis of the muscle fibers.
Freeze‐fracture appearance of the capillary endothelium in the cerebral cortex of mouse brain
Authors: Connell C. J. , Mercer K. L.
Published: February 2005

Extensive tight junctions are located between overlaps of plasma membranes of capillary endothelial cells. Micropinocytotic vesicles are few in number and are seen as invaginations on the A face and as protrusions on the B face. The freeze‐fracture appearance of these cells is consistent with their thin section appearance and their role as the site of the blood‐brain barrier.
Proliferative response to the skin‐sensitizing contact agent dinitrofluorobenzene in lymph nodes in mice
Authors: Schneider Gary B.
Published: February 2005

When dinitrofluorobenzene (DNFB) is applied to the skin in mice, it induces a state of delayed hypersensitivity. During the three days following the application of this contact agent, lymphoblasts accumulate in the diffuse cortex of the lymph node draining the area of sensitization. This accumulation of blast cells – referred to as a blastogenic response – appears to be part of the induction phase of delayed hypersensitivity.

This is an investigation into the origin of the cells of the blastogenic response. There is evidence from other studies that lymphocytes immigrate to the lymph nodes draining a site of sensitization. This paper provides complementary evidence that cellular proliferation in the diffuse cortex of the sensitized lymph node is another source for the accumulation of blast cells. This proliferation has been studied by counting mitotic figures, and by autoradiography after giving 3H‐thymidine in order to determine the number of blast cells undergoing DNA synthesis and the duration of the various phases of the cellular reproductive cycle.

The results show a high degree of correlation between mitotic figures and blast cells in the diffuse cortex of the sensitized lymph nodes, consistent with a population of dividing blast cells. Approximately 80 percent of the blast cells were in the DNA‐synthetic phase of the reproductive cycle at the peak of the blastogenic response, and the cells were dividing with approximately an eight hour generation time.

These results can be interpreted to indicate that the cells of the blastogenic response, although accumulating initially by immigration to the draining lymph node, become a homogeneous, nondifferentiating population of blast cells, all proliferating at near maximal rate to provide the great numbers of blast cells seen three days after application of the sensitizing agent.
Modifications, some cytochemical properties and transport of intralysosomal membranes
Authors: Vidić Branislav
Published: February 2005

The structural alterations of intralysosomal membranes were investigated in the rat lateral nasal and maxillary glands. In addition to conventional electron microscopical procedures, the following cytochemical reactions were applied: acid phosphatase, ruthenium red, phosphotungstic acid, and silver tetraphenylporphine sulfonate. Two forms of intralysosomal membranes were described, the myelin‐like figure and the aligned membranes. The former variety occurred most often in the lysosome and occasionally in some other organelles (e.g., secretory granule, multivesicular body, Golgi apparatus). Some figures were observed in the process of extrusion from the lysosome into the cellular interior. Furthermore, there were indications of the release by the cell of these membranes either into the lumen or toward the basal lamina. The acid phosphatase test revealed an association of the enzyme with the myelinated membrane in the lysosomal medium, in various cellular locations, and in the cellular environment. The possible importance of some interstitial cells in the transport of these membranes from the acinar base outward was noted. The other form, referred to as aligned membranes, occurred only as individual couples within the lysosomal interior. The formation of multilamellar complexes by further cross‐binding of membranous pairs was not observed. They displayed a focal occurrence of globules of apparently lipid material and a continuity with the already existing lipid droplets. Both types of altered membranes stained with phosphotungstic acid at pH 1.5, although they did not stain with silver tetraphenylporphine sulfonate. Most findings suggested that the two membranous varieties represented different patterns in membrane autodigestion.
Prenatal development of the vomer in normal and cleft palate mice
Authors: Sakizlioglu Isik , Frommer Jack , Shiere Frederic R.
Published: February 2005

In mouse fetuses with cleft palate induced by cortisone, the shape of the entire nasal septal structure was slightly altered, due possibly to the lack of palatal shelf contact, but no significant changes occurred in the basic development of the vomer. Nor was any evidence found to show a direct or indirect influence of the vomer on structures involved in the formation of a cleft palate.
“Native” striated collagen produced by chick notochordal epithelial cells in vitro
Authors: Carlson Edward C. , Upson Rosalyn H.
Published: February 2005

We report here the observation of striated collagen produced by notochordal cells in vitro. Fibrils with collagen‐like striations were seen in large intercellular spaces following three days of incubation in vitro. Surprisingly, similar fibrils and large sheets (1,500 Å wide) of collagen showing a 510 Å periodicity were seen in notochordal tissues cultured in the presence of β‐aminopropionitrile (BAPN), a known inhibitor of cross‐linking in tropocollagen. These observations support the view that the notochord should be considered one of several embryonic epithelial tissues known to secrete collagen.
Lethocerus flight muscle paramyosin: Antibody localization and electrophoretic studies
Authors: Levine Rhea J. C. , Dewey Maynard M. , Elfvin Myra , Walcott Benjamin
Published: February 2005

Antibody specific for Limulus paramyosin stains the A bands of Lethocerus flight muscle sarcomeres. SDS‐polyacrylamide gels of both Limulus telson and Lethocerus flight myofibrillar preparations show bands with mobility similar to that of purified Limulus paramyosin.
Origin, differentiation and renewal of the four main epithelial cell types in the mouse small intestine IV. Paneth cells
Authors: Cheng Hazel
Published: February 2005

The origin, differentiation and fate of Paneth cells in adult mouse small intestine was examined by electron microscopic radioautography at various times after a single injection of 3H‐thymidine.

The Paneth cell population consists of 23% young Paneth cells with granules less than 2 μm in diameter, 63% mature Paneth cells with granules 2–3 μm in diameter, and 14% old Paneth cells with granules greater than 3 μm in diameter.

Light and electron microscopic radioautography confirms that typical Paneth cells are not labeled 1 hour after 3H‐thymidine injection and, therefore, are not capable of proliferation. However, labeled cells with a few small Paneth cell granules are first observed 12 hours after an injection. Except for the presence of granules, these cells are indistinguishable from the highly proliferative crypt‐base columnar cells. It is, therefore, suspected that Paneth cells are derived from crypt‐base columnar cells.

With time after injection, differentiation proceeds: stacks of rough endoplasmic reticulum cisternae appear, the granules become progressively more numerous and larger, and the nucleus acquires an irregular shape. Labeled mature Paneth cells are observed by five days after injection.

Unlike the other three cell types, Paneth cells do not migrate up to the villus epithelium and thus are not lost through the extrusion zone. Instead they undergo degeneration in the crypt‐base and are eventually phagocytosed by an adjacent crypt‐base columnar cell.
Ontogeny of human fetal lymph nodes
Authors: Bailey Raymond P. , Weiss Leon
Published: February 2005

Developing lymph nodes from 30 human embryos and fetuses with crown‐rump lengths (CRL) of 18 mm (5.6 wk) to 245 mm (26 wk) were examined by light microscopy. The nodes were embedded in araldite, and the sections examined were approximately 1 μ in thickness. The development of nodes was divided into three stages: 1. the lymphatic plexus and connective tissue invagination (30 mm to 67 mm CRL); 2. the early fetal lymph node (43 mm to 95 mm CRL); and 3. the late fetal lymph node (CRL greater than 75 mm). The lymphatic plexus was formed by connective tissue invaginations and bridges which divided a lymph sac into a meshwork of channels and spaces. Connective tissue invaginations were endothelially‐lined and were surrounded by lymphatic space. Reticular cells, macrophages, and blood vessels were found in these invaginations. Early fetal lymph nodes were formed from invaginations when the cellular density and lymphocyte content increased. The lymphatic space surrounding the early node was the developing subcapsular sinus. With further development the early node became packed with lymphocytes, increasing the cellular density and size of the node. The connective tissue surrounding the subcapsular sinus condensed to form the capsule. Afferent lymphatic vessels pierced the capsule. Capillaries, veins, postcapillary venules, and occasional arteries were found in early and late nodes.
Morphological and histochemical studies on a PAS‐positive granular leukocyte in blood and connective tissues of Catostomus commersonnii Lacépède (Teleostei:Pisces)
Authors: Barber D. Louise , Westermann Jean E. Mills
Published: February 2005

This study was undertaken to identify an ubiquitous granular leukocyte found in Catostomus commersonnii Lacépède. The cell contains large, numerous, strongly PAS‐positive cytoplasmic granules, an eccentric nucleus and prominent, persistent juxtanuclear space. It develops in the hemopoietic tissue of the kidney, and mature cells are found not only in kidney and peripheral blood but also in areas of connective tissue where mast cells are usually located. Electron microscopy confirms the presence of a large Golgi apparatus, unlamellated cytoplasmic granules and extensive rough‐surfaced endoplasmic reticulum.

Histochemical studies show that the cytoplasmic granules are alcianophobic, non‐metachromatic and unstained by acridine orange. Histamine is detectable spectrophotometrically in kidney tissue, but the PAS‐positive granular leukocyte does not consistently degranulate after treatment with histamine liberator 48/80.

The authors suggest that while the PAS‐positive granular leukocyte is not identical with classical basophils/mast cells, which are absent in C. commersonnii, it may represent an evolutionary precursor of these cells.
Comparative anatomical study of the hyoid apparatus in selected primates
Authors: Hilloowala R. A.
Published: February 2005

This paper embodies a comparative study of the hyoid apparatus in six species of primates. There is a direct correlation between a predominantly herbivorous diet and an increase in the relative size of the basihyal (the body) of the hyoid bone.

The basihyal has a deep “cup‐shaped” concavity in the howler but is very flat in the marmoset. The baboon, rhesus and capuchin fall in between these two extremes. The configuration and size of the basihyal are directly proportional to the presence or absence and the size of the median air‐sacs. Of the species studied, the posterior cornu (thyrohyal) of the hyoid bone is present in all the species, but the hypohyal is present only in the baboon, rhesus and capuchin. A true styloid process is found only in the baboon, although the rhesus has a bony spicule. All except the howler have a stylomandibular ligament from which arise the stylohyoid, stylopharyngeus and styloglossus muscles. The anterior bellies of the two sides of the digastric muscle are truly united only in the marmoset, but are approximated in the baboon and rhesus. The stylohyoid muscle at its insertion into the basihyal is pierced by the intermediate tendon of the digastric muscle in the rhesus and capuchin, but not in the howler and baboon. In the marmoset the presence of a stylohyoid muscle is variable.
Tubules and filaments in satellite cells and axons of sensory neurons
Authors: Peach Roy
Published: February 2005

Satellite cells covering the axon hillock region and initial axon process of the neurons of rat and mouse trigeminal ganglia contained numerous parallel microtubules and microfilaments. These were oriented circumferentially to axonal neurofilaments and neurotubules. The latter were sometimes grouped in fascicles. The results suggest a specialized role for the supporting cell in this region and that fascicles of neurotubules are not related to action potential initiation.
Effect of steroids on definitive localization of primordial germ cells in the chick embryo
Authors: Swartz William J.
Published: February 2005

It has been suggested that PGCs are attracted to developing gonads by a chemotactic‐like agent secreted by the gonads and that this agent might be steroidal in nature. This study was undertaken to ascertain whether specific exogenous steroid hormones exert an influence on germ cell colonization of the gonads, by enhancing, inhibiting or otherwise interfering with it. Testosterone cypionate in cottonseed oil, crystalline testosterone propionate, estrone in aqueous suspension and crystalline estradiol‐17β were administered to chick embryos at 33 hours incubation. Normally developed embryos, those receiving cottonseed oil (vehicle for testosterone cypionate) and those receiving cholesterol served as controls. A decrease in the number of germ cells in the gonadal area at five days of incubation occurred in all groups receiving the androgens and estrogens. However, in only one group (that receiving testosterone cypionate) was this decrease found to be significant. The mean number of germ cells found in the cottonseed oil controls and the cholesterol controls closely paralleled that of the normally developed controls. Normal asymmetry in the distribution of the germ cells favoring the left side in the chick was not affected in any of the groups; however, the percentage distribution of the germ cells between the right and left gonads at this early stage appeared to be affected.
The mode of lymphocyte migration through postcapillary venule endothelium in lymph node
Authors: Farr Andrew G. , De Bruyn Peter P. H.
Published: February 2005

The pathway of migration of lymphocytes across the walls of the postcapillary venules was studied in lymph nodes of rats. By means of serial sections, it was determined that lymphocytes enter the venule wall through the endothelial cells and not through the intercellular spaces. After the endothelial cell has been penetrated, the lymphocytes enter the intercellular spaces, from where they gain access to the lymphatic parenchyma. It cannot be excluded, however, that in some instances the path of migration of a lymphocyte is entirely through an endothelial cell from lumen to subendothelial space. While perforating an endothelial cell, a migrating lymphocyte may be in simultaneous contact with the vascular lumen, the intercellular space, and the subendothelial tissue.
Development of the implantation chamber in the pregnant bitch
Authors: Barrau Marny D. , Abel John H. , Torbit C. A. , Tietz W. J.
Published: February 2005

Uteri taken from 25 bitches at various times during the early stages of pregnancy were studied cytologically to determine how the implantation chamber developed and how fetal‐maternal relations were established. On day 13 after the end of estrus, knobs of trophoblastic syncytium formed and became wedged between cells of the uterine luminal epithelium. The syncytium quickly spread along the uterine lumen and into the mouths of the glands, dislodging and surrounding maternal cells. As invasion continued trophoblastic villi, consisting of cores of cytotrophoblast covered by a continuous layer of syncytium, penetrated deeper into the endometrium. The syncytium spread to surround maternal vessels and decidual cells. By day 26 the trophoblast had extended down to the large lacunae. Here syncytial trophoblast covering tips of the villi degenerated, leaving cytotrophoblast exposed to the necrotic zone. These cells possessed characteristics of absorbing cells. Hematomas were formed by focal necrosis of fetal and endometrial tissue at the poles of the implantation sites. Large pools of extravasated blood accumulated and red blood cells were phagocytized by surrounding trophoblastic cells.

Therefore, the endotheliochorial relationship in the canine placenta appeared to be established by syncytial trophoblast invading a cellular endometrium. In the necrotic zone and hematomas, cellular trophoblast may have lost its syncytial covering, but elsewhere maternal vessels and decidual cells in the placenta were in direct contact only with syncytial trophoblast.
Cytodifferentiation of striated duct cells and secretory cells of the convoluted granular tubules of the rat submandibular gland
Authors: Cutler Leslie S. , Chaudhry Anand P.
Published: February 2005

The structural and functional development of the striated ducts and convoluted granular tubules (CGT) of the rat submandibular gland (SMG) were studied by electron microscopy and alkaline protease chemistry. Development of the SMG was followed from 14 days of gestation through 30 weeks of age. The specialized morphology of the basal aspect of the striated duct cells arises from cellular extensions which are first seen at 20 days of gestation. These processes elongate and intertwine with similar processes from adjacent cells, and as the cells enlarge the processes are compressed together giving the appearance of “infolding” of the basal plasma membrane. Mitochondria migrate to the basal part of the cell and are seen in close relationship to the cellular extensions throughout the development of these cells. Development of the striated duct is complete by one week after birth. The CGT develop from the proximal portions of intralobular striated ducts. At one week after birth, cells of the proximal striated duct demonstrate apical vacuoles. By two weeks after birth these vacuoles are replaced by distinct zymogen‐like granules. There is a progressive accumulation of large numbers of secretory granules in the CGT cells as the animals age. However, rough endoplasmic reticulum is a relatively inconspicuous cellular component throughout development. The accumulation of alkaline protease activity in the gland closely parallels the pattern of granule accumulation.
A light and electron microscopic study of the pineal gland of the ground squirrel, Citellus tridecemlineatus
Authors: Povlishock John T. , Kriebel Richard M. , Seibel Hugo R.
Published: February 2005

The pineal gland of the 13‐lined ground squirrel (Citellus tridecemlineatus) has been examined at the light and electron microscopic level. This gland is composed of low‐density parenchymal cells interspersed among which are occasional glial, vascular and neural elements. Punctuating the glandular parenchymal mass are prominent perivascular and intercellular spaces.

The parenchymal cells possess numerous mitochondria and less prominent profiles of rough and smooth‐surfaced endoplasmic reticulum. Golgi apparatus, microtubules and lipid droplets of varying size and electron density constitute regular cytoplasmic features, with dense‐core vesicles being present occasionally. The parenchymal cells have numerous processes. One among these in each cell extends for several micra to terminate in a bulbous expansion containing both clear and dense‐core vesicles and occasional electron‐dense inclusions. These bulbous terminals are found within the perivascular and intercellular spaces where they course in close proximity to both other parenchymal elements and axon terminals. Glial cells and their processes invest the pineal periphery and incompletely separate the parenchymal cells.
Neuroanatomical clues to peripheral locomotor control in small crustaceans (Artemia salina)
Authors: Kane Eileen S. C.
Published: February 2005

Brine shrimp (Artemia salina) were prepared for light and electron microscopy at several stages. Immersion‐fixed, rapid Golgi impregnations demonstrated two distinct neuronal types in thoracic appendages of mature, freely swimming Artemia. Isolated motor neurons had large cell somas and thick, radiating dendrites at the body wall‐limb junction. A long, elaborate axon extended into the limb. Groups of a second type of neuron with smaller somas and very thin, radiating processes occurred in the distal limb near presumably tactile bristles. Thick axons from motor neurons were traced to terminals associated with limb muscle. Both muscle and axon were best seen with Nomarski optics. Motor axons possessed elongate, irregularly shaped boutons en passant and morphologically variable boutons terminaux; the latter included huge endings with knobbed projectiles arising from thick collaterals, or smaller, round boutons from thin collaterals. In addition, a thick, unidentified axon coursed longitudinally within the central body wall, sending short collaterals peripherally. The elaborate peripheral neurons described in this Golgi study may be anatomical correlates for the extraordinary coordination of mature brine shrimp. Because Artemia movements resemble those of leech and decapods, which have been studied extensively electrophysiologically, the possibility of similarly elaborate peripheral structures supplementing central control of locomotion in those invertebrates should be considered.
An unusual type of cilium
Authors: Kubota Kimo , Malloy John J. , Low Frank N.
Published: February 2005

The connective tissue cells of the dentinal pulp of unerupted dog teeth possess occasional cilia. Internally there are 4 to 8 peripheral doublets and one central doublet. Nine peripheral doublets are observed only close to or near the basal body.
Organ culture of osteopetrotic (ia) rat bone: Evidence that the defect is cellular
Authors: Nyberg Leroy M. , Marks Sandy C.
Published: February 2005

Calvarial bone from osteopetrotic (ia) rats and normal littermates has been cultured in a chemically defined medium supplemented with homologous serum to test for the presence of inhibitors or the absence of promoters of bone resorption in mutant serum. In addition, the response of mutant and normal bone to parathyroid extract and hydrocortisone was tested in vitro. The results indicate that mutant and normal serum do not differ with respect to their ability to support bone resorption and that ia bone responds to hydrocortisone but not parathyroid extract in organ culture. These data indicate that the skeletal defect in ia rats is not humoral but cellular.
Ultrastructural evidence for the uptake of 5,6‐dihydroxytryptamine in the frog's gustatory cell
Authors: Nada Osami , Hirata Kazuho
Published: February 2005

The fungiform papillae of the frog were examined electron microscopically after a single injection of 5,6‐dihydroxytryptamine (5,6‐DHT). Thirty minutes after 5,6‐DHT injection, numerous vesicles partially occupied with dark material were found in the cytoplasm of gustatory cell processes. Three days after the drug treatment, the majority of vesicles were completely filled with dark material so that their limiting membrane became obscure, while the terminal portions of gustatory cells showed no evidence for fine structural alteration indicative of drug retention. In addition, clear vacuoles, suggesting a degenerative change induced by the uptake of the neurotoxic agent, occurred in the cytoplasm of gustatory cell processes. It is suggested that the uptake of 5,6‐DHT in gustatory cells may reflect the presence of an indoleamine, probably 5‐hydroxytryptamine (serotonin).
Intercellular relationships in the external glial limiting membrane of the neocortex of the cat and rat
Authors: Williams Vick
Published: February 2005

The external glial limiting membrane of the cerebral cortex appears to be a complete astrocytic mantle covering the pial surface of the molecular layer. It consists of flattened cell bodies arranged singly or in small groups spaced about 100 μ apart and multitudes of interdigitating processes arrayed in layers. The glial mantle is thicker in the sulci than on the gyri. It is covered externally by a basal lamina which is associated with collagenous fibrils and cells of the pia mater. The extracellular space in aldehyde‐perfused material appears as a regular, electron‐lucent interval 150 Å wide between adjacent cell membranes. Gap junctions are frequently encountered in the external glial limiting membrane; desmosomes are present between astrocytic processes but are seen much less often.
The hypothalamic magnocellular neurosecretory system of the guinea pig. II. Immunohistochemical localization of neurophysin and vasopressin in the fetus
Authors: Silverman A. J.
Published: February 2005

The development of the hypothalamic magnocellular neurosecretory system of the fetal guinea pig was examined by immunohistochemistry. Neurophysin was first observed in the supraoptic nucleus (SON), median eminence (ME) and posterior pituitary (PP) on day 40 of gestation. It was not regularly present in the paraventricular nucleus (PVN) until day 47. Vasopressin was first observed in the SON, ME and PP on day 45. In the median eminence immunoreactive deposits indicative of both peptides were observed in both the fibers of the hypothalamo‐hypophysial tract (H‐HT) in the presumptive zona interna as well as in axons projecting to the developing primary portal plexus.
Proliferative kinetics of large and small intraepithelial lymphocytes in the small intestine of the mouse
Authors: Röpke C. , Everett N. B.
Published: February 2005

The proliferative kinetics of the intraepithelial lymphocytes (IL) of the mouse intestine have been evaluated. By inducing mitotic arrest it was found that large IL — constituting about 50% of the IL — showed a mitotic rate of 2.3. Autoradiographic results obtained after two different schedules of 3H‐thymidine injections showed that 30% of the large IL were in DNA synthesis, and that the large IL were renewed at a rate comparable to that of blast cells from Peyer's patches, mesenteric lymph nodes and thoracic duct lymph. The small IL were renewed very rapidly compared to small lymphocytes of peripheral lymphoid tissues, although small lymphocytes with lifespans of several weeks were also present in the epithelial sheet. By the use of intestinal perfusion, in vivo, it was estimated that the loss of lymphocytes from intestinal villi into the lumen of the gut was negligible, and it is concluded that the most probable kinetic model for the majority of IL is: B and T lymphoblasts invade the epithelium and undergo mitosis. B lymphoblasts give rise predominantly to plasma cells, and T lymphoblasts give rise to small lymphocytes — probably long‐lived — which reenter the circulation.
The effects of preparative procedures for scanning electron microscopy on the size of isolated lymphocytes
Authors: Schneider Gary B.
Published: February 2005

The diameter of lymphocytes, isolated from a sample of peripheral blood by Ficoll‐Hypaque sedimentation, was determined after eight different steps in the preparative procedure for scanning electron microscopy (SEM). There was a 43% total reduction in mean cellular diameter of the lymphocytes studied, the diameter dropping from 8.4 μm prior to fixation, to a final diameter of 4.8 μm in the cells examined under the scanning electron microscope. The bulk of this shrinkage occurred during critical‐point drying. In view of this finding, caution should be exercised in describing detailed cell surface morphology by SEM when similar preparative procedures are employed.