bluuebunny/crossref_metadata_2025 huggingface dataset:
Ovarian, oviductal, and adrenal vascular connections in female lizards (genus Anolis)
Authors: Jones Richard E. , Summers Cliff H. , Austin Harriet B. , Smith Hobart M. , Gleeson Todd T.
Published: February 2005

The urinogenital blood vessels of Anolis equestris and A. carolinensis were studied using dissection, injection of silicone rubber, and histology. A new blood‐vascular connection between small veins in the pampiniform plexus at the base of the ovary and an ostial extension of the secondary oviductal vein is described. Chemical messengers could thus be carried in the blood from the ovarian venous drainage to the oviduct. Furthermore, close apposition of the secondary oviductal vein and artery provides an anatomical basis for countercurrent exchange of these messengers. A circular venous arcade, involving the supracardinal vein and branches of the oviductal veins, also is described; this arcade could serve to deliver adrenal hormones to each oviduct.
Hypotelorism in trisomy 1‐producing mice
Authors: v. Domarus Helmut
Published: February 2005

Trisomy 1 embryos in mice are smaller in all dimensions, showing a developmental retardation as compared with euploid mice. Very rarely the trisomic embryos develop a typical hypotelorism with holoprosencephalon and missing olfactory nerves. Corneal distances, angles between the optic nerves and further microscopic examination showed no intermediate forms between the trisomy 1 embryos and the rare trisomy 1 embryo with hypotelorism. There seems to be a threshold, beyond which the major developmental derangement occurred. This is an experimental model showing parallels to the occasional varying phenotypes in human trisomies.
Effects of age and strain differences on the red nucleus of the mouse mutant Dystonia musculorum
Authors: Stanley Edith , Messer Anne , Strominger Norman L.
Published: February 2005

The mouse mutant Dystonia musculorum exhibits pathological changes in the magnocellular neurons of the red nucleus. The present study shows that allelic differences occur in the age of onset and severity of this pathology. The magnocellular neurons of the Jackson allele (dtJ) almost completely disappear prior to 4 weeks of age while some of these cells are retained in the adult of the Albany strain (dtAlb). However, acetylcholinesterase histochemistry suggests that the remaining rubral neurons in dtAlb are nonfunctional. This pathology may contribute to the severe locomotor disturbances seen in these animals.
Blood vessels of the Peyer's patch in the mouse: I. Topographic studies
Authors: Yamaguchi K. , Schoefl G. I.
Published: February 2005

The topographic distribution of blood vessels in Peyer's patches of mice was studied by light and scanning electron microscopy with whole mounts of flattened gut segments and vascular corrosion casts. Peyer's patches are imbedded in the intestinal wall and share its blood supply. Two to four mural trunks may contribute to the area of the patch. In and around the lymphoid nodules the microcirculation is highly specialized. The nodule is permeated by a meshwork of fine capillaries that is supplied by arterioles entering on the serosal and lateral surfaces. Blood flow to the lymphoid nodule appears tobe monitored by arterial sphincters; the dense lymphatic tissue can also beby passed by arteriovenous communications. An extensive venous network encircles the nodule. Most of these venules are lined by high endothelium which is penetrated by lymphocytes. The geometry of these vessels suggests a slow and turbulent flow in these vascular segments that may aid margination of lymphocytes. A planar capillary plexus lies subjacent to the mucosal epithelium in the dome area.
A morphometric analysis of rat ventral prostate in organ culture
Authors: Martikainen Paula , Suominen Jyrki
Published: February 2005

A stereologic, morphometric method was used for determining the quantitative and qualitative changes in the rat ventral prostate during organ culture. The volume density of epithelium (VVEP), lumina (VVLU), and interstitium (VVIT) as well as the proportion of epithelium of the tissue, (VVEP) (VVEP+VVIT), the length density of tubular structures (Lv), mean diameter of the lumina (DLU), height of the epitheluium (h), and mean width of the interacinar tissue (λAP) were evaluated. In the perfusion‐fixed prostate these parameters gave the closest approximation for the in vivo situation: VVEP was 0.19 mm3/mm3; h 19.5 μm; VVEP/(VVEP+VVIT) 0.63 mm3 VVLU 0.70 mm3/mm3; DLU 230 μm; VVIT 0.11 mm3/mm3; λap 84.1 μm; and Lv 17.5 mm/mm3. Dissection of the prostate for culture caused leakage of prostatic secretions and a consequent diminution of VVLU (0.41 mm3/mm3) and DLU (151 μm), as well as folding of the epithelium and distortion of the interacinar tissue (VVIT 0.25 mm3/mm3). During 10 days culture in a defined medium, the prostate under‐went involutive changes including loss of total weight, a decrease of VVEP, and an increase of VVIT. During the first day a stimulatory effect on the epithelium occured, which might have been caused by a loss of androgenic control or by substances in leaking secretions. Testosterone postponed many of these changes and maintained the secretory function better. Thus, on day 4 the morphology of the prostate resembled better the situation in vivo than at the beginning of involutionary culture. However, later during culture changes, similar to those found without testosterone but weaker, were noted.

Statistical analysis of data showed that it is more advisable to use many pieces from one prostate lobe rather than to use many animals. Analysis of one slice is also sufficient to give relevant data on that piece.
Transverse periosteal sectioning and femur growth in the rat
Authors: McLain James B. , Vig Peter S.
Published: February 2005

Circumferential cuts through the periosteal covering of long bones have been demonstrated to transiently increase epiphyseal growth. This effect appears to be independent of vascular changes accompanying surgery and has been hypothesized to relate to releasing tension in the periosteal envelope. This study was designed to address problems of previous investigations by controlling for the effects of the surgical procedure and by using regression analyses to analyze intra‐ and interanimal variations in the length and proportionality of the femur in experimental, sham, and control Sprague‐Dawley male rat littermates. Experimental animals received circumferential periosteal sectioning of the right femur and no operation to the left limb. A sham operation without periosteal sectioning was performed on the right femur in the sham group. Right to left differences were analyzed using two multiple regression models; one involved three absolute length measurements as the dependent variables, while the other used the three ratios of these length measurements as the dependent variables. The ratio measures were utilized to reflect changes in bone proportionality.

Circumferential periosteal section was followed by an alteration in the shape of rat femurs at 2 weeks postsurgery with a slight retardation of the length dimension from medial epicondyle to head of the femur and an overgrowth of the length dimension from the lateral epicondyle to the greater trochanter. The sham procedure produced a proportional decrease in all length measurements. The experimental procedure was also associated with surface bone apposition at the site of section. At 3 weeks postsurgery, normalization of bony contours between sham, experimental, and control groups had occurred; however, there were still some statistically significant decreases of length dimensions in the sham and experimental groups. In the experimental group the length measurement involving the weight‐bearing head of the femur remained reduced at 3 weeks postsurgery.

It is hypothesized that the functional demands of the long bone play an important role in the effect of periosteal regulation on growth. In situations where a normal tensive force is exerted on the bone, the periosteal envelope will act to restrain epiphyseal growth. When the bone is under a normal compressive force the release of periosteal tension is not a quantitatively significant stimulus to epiphyseal growth and the effects of surgical intervention and muscle trauma will play a more important role in the growth response of the epiphyses.
Ultrastructure of the bone marrow in three murine strains with non‐malignant lymphoproliferative syndromes NZBxW, BXSB, and MRL/1pr
Authors: Brookoff Daniel , Weiss Leon
Published: February 2005

Three mouse strains, NZBxW, BXSB, and MRL/1pr have well documented congenital lymphoproliferative syndromes and lupus‐like disease. We studied the ultrastructures of the marrows of these mice searching for a model for intramedullary lymphopoiesis. In MRL/1pr, the strain with the most severe disease, the marrow was largely populated by large lymphocytes associated with dark branching stromal cells. These stromal cells are apparently of a recently recognized cell type which has been associated with extremely accelerated eosinophilopoiesis and erythropoiesis. They did not appear in the lymph nodes and spleens of the MRL/1pr mice or in the marrows of the other strains. BXSB marrows showed some non‐proliferant lymphocytic infiltrates and heightened erythropoiesis while NZBxW marrows resembled controls. We suggest that the dark stromal cells in the MRL/1pr marrows were important in supporting the production or differentiation of lymphoid precursor cells.
Electron microscopic study of intramembranous changes in protein‐extracted peripheral nervous system myelin
Authors: Cullen Michael J. , Peterson Richard G. , deF. Webster Henry
Published: February 2005

Sciatic nerves from young mice were incubated for 2–8 hours in 0.5% Triton X‐100 in 0.5 M ammonium acetate, a solution which solubilizes the large and small basic proteins of the myelin sheath. As previously noted (Peterson and Gruener, 1978), myelin sheaths from treated nerves extensively split and unravelled along major dense lines. Small focal areas of compact myelin remained. In freeze‐fracture replicas, areas of myelin with lamellar splitting contained few intramembranous particles, while membrane areas with greater than normal densities of particles were associated with the patches of compact myelin membrane. Fixation for as short a time as 15 minutes stabilized the myelin membrane enough to prevent the Triton X‐100 effects, even when incubations were extended to 20 hours. Controls, both untreated and 0.5 M ammonium acetate‐treated nerves, had predominantly compact myelin sheaths; their leaflets were covered with numerous intramembranous particles. The data suggest that Triton X‐100 alters the compact structure of peripheral nervous system myelin. In areas where lamellae are split and separated, there is a loss of intramembranous particles. It appears that the loss of intramembranous particles is related to the removal of the basic proteins which are located in major dense line regions of compact myelin sheaths.
Intercellular contacts of lymphocytes during migration across high‐endothelial venules of lymph nodes. An electron microscopic study
Authors: Campbell Ferrell R.
Published: February 2005

The migration of lymphocytes across the wall of high‐endothelial venules was studied by electron microscopic examination of murine lymph nodes fixed with glutaraldehyde and tannic acid. Regions of close membrane apposition, referred to in the present study as “intercellular contacts,” were observed between migrating lymphocytes and endothelial cells of the vessel wall. At high magnification the intercellular contacts resolve into pentalaminar structures resembling gap junctions. However, the location of these contacts suggests that they are regions of membrane adherence utilized for locomotion of the lymphocytes across the endothelium. At present, it is unclear whether these intercellular contacts are communicating junctions or sites of membrane adherence.
Distribution and size of Boettcher cells in the little brown bat, rabbit, and other species
Authors: Ramprashad Fred , Money Kenneth E. , Landolt Jack P. , Correia Manning J. , Laufer Jerry
Published: February 2005

The distribution and size of Boettcher cells were determined from serial sections of the temporal bones of four little brown bats and six rabbits. In addition, one harp seal and one two‐toed sloth were examined. In the little brown bat, the heights of the Boettcher cells measured 4–8 μm and they were found throughout much of the length of the cochlea. There were four rows in most of the lower basal coil, five rows in the upper basal coil, and four rows in the middle coil. In the rabbit there were nine rows in the basal coil and 12 rows in the middle coil. The heights of the Boettcher cells were approximately 14 μm in the rabbit. In the two‐toed sloth, Boettcher cells were sparsely distributed along the basal coil; similarly, in the harp seal, Boettcher cells were confined solely to the basal coil, where there were only three rows, which measured approximately 18 μm in height. The distribution and size of Boettcher cells in the rabbit and the little brown bat were compared to those in other mammalian species.
Relationship between the quality of fixation and the presence of stippled material in newly formed enamel of the rat incisor
Authors: Nanci A. , Warshawsky H.
Published: February 2005

Extracellular accumulation of a granular material that is presumed to be an organic “precursor” to mineralized enamel has been reported. This material, generally referred to as “stippled material,” was observed mainly after immersion fixation with osmium tetroxide. In studies with perfusion fixation, the presence of stippled material was inconsistent. Therefore, it appeared that the occurrence of stippled material was dependent on the method of fixation. To test this assumption, tissues were fixed by immersion in either osmium tetroxide or glutaraldehyde and by perfusion with either glutaraldehyde or a mixture of acrolein, glutaradehyde, and formaldehyde. It was found that as the quality of cellular preservation improved, the occurrence of stippled material decreased. Since no stippled material could be found in material judged to be well fixed, it was concluded that stippled material is not an extracellular precursor to mineralized enamel, but is a breakdown product resulting from poor fixation.
Formation of multinucleated fibroblasts in the periodontal ligaments of old mice
Authors: Cho Moon‐Il , Garant Philias R.
Published: February 2005

Multinucleated cells were observed to account for more than 17% of all cells in the periodontal ligament (PDL) of 20‐month‐old mice. The number of nuclei contained in sections of these cells ranged from 2 to 17, with over 50% of the multinucleated cells containing four or more nuclei within the plane of section. The multinucleated cells contained several cytoplasmic features resembling those previously described by the authors as characteristic of PDL fibroblasts. The multinucleated cells did not resemble osteoclasts or foreign body giant cells. It is suggested that fibroblasts develop a tendency to fuse and form multinucleated cells in the aged PDL. Similar cells were not observed in the PDL of young (5‐week‐old) mice or in the tail tendon at any age.
Meckel's diverticulum. I. Extramedullary myelopoiesis in the yolk sac of hatched chickens (Gallus domesticus)
Authors: Oláh Imre , Glick Bruce
Published: February 2005

We have described an extramedullary myelopoietic tissue located in the wall of the yolk sac. This myelopoietic site is absent at hatch and it produces only granulocytic and monocytic cells during the regression of the yolk sac from 2 to 7 weeks of age. The granulocytic and monocytic cells are located in two distinct zones. The monocytic cells migrate close to the lumen of the yolk sac where they may fuse and form giant cells. There are no mature granulocytes present. Cell migration has not been observed. Therefore, the fate and function of the young granulocytic cells are unknown. In this extramedullary myelopoietic tissue, the absence of erythrocyte and thrombocyte formation may indirectly suggest that these cells develop together in sinuses that are lacking in the wall of the yolk sac.
Phenoxyethanol as a nontoxic substitute for formaldehyde in long‐term preservation of human anatomical specimens for dissection and demonstration purposes
Authors: Frølich Karin W. , Andersen Ling Merete , Knutsen Arne , Flood Per R.
Published: February 2005

Formaldehyde has recently been declared a potential carcinogen. Occupational health authorities throughout the world are therefore likely to put stricter regulations to its use also within anatomical disciplines.

We have been able to reduce the atmospheric concentration of formaldehyde in our dissection rooms to below the detection limit of a conventional Dräger tube multigas analyzer (i.e., below 0.5 ppm or 0.6 mg formaldehyde/m3 air), by extracting previously formaldehyde‐fixed material for more than 3 months in 1% phenoxyethanol in tap water.

In this fluid our material has remained soft and flexible with a consistency and color retention suitable for dissection and demonstration purposes for up to 10 years. Fungal attacks are rare and we have been unable to raise bacteria from such specimens. Even the microscopical structure of most tissues remains satisfactory after 5 years in 1% phenoxyethanol.

The unpleasant and irritating smell traditionally felt in dissection rooms is almost absent in out facilities, but some of our students still mention slight odor, headache, drowsiness, and mild eye, nose, and throat irritation during their dissection practice periods.
Morphometric study on vasularization in the tail musculature of the anuran tadpole by scanning electron microscopy: I. Prometamorphic stage
Authors: Horiguchi Tsuyoshi , Watanabe Kyozo
Published: February 2005

Vascularization in the tail musculature, which contains red and white muscle fibers, of the prometamorphic anuran tadpole was analyzed quantitatively by scanning electron microscopy (SEM). The sample was fixed in glutaraldehyde and osmium tetroxide; this was followed by freeze‐fracturing in liquid nitrogen. As good ultrastructural preservation and reliable identification of capillaries were given by this technique, various morphometric parmeters, cross‐sectional capillary area in particular, could be measured exactly.

In red muscle fiber that had a small cross‐sectional area (2,060.1 μm2), high capillary density (1,283.5 capillaries/mm2) and a large cross‐sectional capillary area (96.4 μm2) was found. Although white fiber (9,372.2 μm2) was 4.6 times greater than red fiber in cross‐sectional fiber area, capillary density (95.8 cappilaries/mm2) and cross‐sectional fiber area, capillary area (29.5 μm2) were 13.4 times and 3.3 times smaller than those of red fiber, respectively. From these morphometric values the following parameters were evaluated; (1) capillary/muscle fiber number ratio of red muscle fiber (2.64) was 3.0 times greater than that of white fiber (0.89); and (2) total cross‐sectional capillary araa per crosssectional area of one muscle fiber was 44.0 times greater for red fiber (1.235.4 μm2/104 μm2) than for white fiber (28.1 üm2/104 μm2). Comparison of the latter parameter between the different fiber types may reflect the differences of real blood supply to them; i.e., red fiber was supplied a 44.0‐times richer blood flow than white fiber.

Advantages of morphometric study by SEM, and the relationship between obtained parameters for vascularization and blood supply to the different muscle fiber types, are discussed.
Effects of intraventricular injections of 6‐hydroxydopamine on anterior pituitary cell proliferation
Authors: Lewiński Andrzej , Konopacki Jan , Pawlikowski Marek , Lewińska Maria K. , Smith Nancy K. R. , Reiter Russel J.
Published: February 2005

Effects of intraventricular injections of 6‐hydroxydopamine (6‐OHDA; 200 μg/20 μl vehicle) on anterior pituitary cell proliferation in rats have been investigated by means of the colchicine metaphas‐arrest techniques. In those groups of animals receiving 6‐OHDA alone or 6‐OHDA plus desmethylimipramine (DMI, 25 mg/kg body weight i.p.), where the mean mitotic activity rates (MMARs) were initially low at 48 hours, an increase of MMARs was observed at 96 and 144 hours after the drug injections. At 144 hours after drug administration, the MMARs values in the 6‐OHDA‐injected group and in the 6‐OHDA+DMI‐treated group were significantly higher than those in the control groups. This increase of MMARs resulted from the enhancement of acidophilic and chromophobe cell proliferation. The low MMARs at 48 hours after 6‐OHDA injection are probably a result of dopamine release from damaged nerve endings; the enhancement of MMARs (particularly evident in the 6‐OHDA+DMI‐treated group) at 96 and 144 hours after drug adminstriation is presumably related to a deficiency of dopaminergic control of anterior pituitary cell proliferation.
Rat uterine tissue and cell responses to the presence of plain and indomenthacin‐delivering IUDs
Authors: Page C. C. , Hurst P. R. , Spears G. F. S.
Published: February 2005

Plain silastic intrauterine devices or those containing 270 m̈g of indomethacin were inserted into the caudal portion of one uterine horn of mature Wistar rats. After a 3‐week period animals were fixed by perfusion on the morning of day 2 after estrus. Segments of uterine tissue corresponding to regions adjacent to and cranial to the devices as well as an equivalent portion of the contralateral horn were embedded in glycol methacrylate. A group of control animals without any form of device were treated in an identical manner. Sections cut from these segments were evaluated by grid‐point stereology to ascertain changes in tissue volumes and cell populations. It was found that the presence of plain devices induced hypertrophy in the stroma and myometrium of the portion of the uterus adjacent to the device. The presence of indomethacin in such devices prevented stromal hypertrophy.

No changes in populations of fibroblasts or areas of glandular or vascular tissue were evident in any treatment group. Cell populations of neutrophils, eosinophils, and mononuclear cells, however, were elevated in the superficial stroma of the horns bearing either type of device; this feature was more pronouced for neutrophils in the presence of the indomethacin devices. Neutrophils, rather than eosinophils, predominated in the epithelia of the uterus bearing either type of IUD. Conversely, eosinophil populations were reduced in the superficial tissues cranial to the devices delivering indomethacin. Neutrophils and mononuclear cells were also found to be elevated in the deep stroma of tissues adjacent to both the plain and medicated device.
The relationship of epithelial cell types in the ventral prostate glands of castrated mice treated with testosterone
Authors: Sinha Akhouri A. , Bentley Michael D.
Published: February 2005

The purpose of this study was to determine the relationship of epithelial cell types in the ventral prostate glands of castrated mice treated with testosterone during the period of maximum DNA synthesis, mitosis, and restitution of the epithelium. Of 33 adult mice, ten were used as normal controls, six were used as castrated controls, at day zero of treatment, and 17 castrates were treated with testosterone for 1 through 8 days. Selected normals, castrates, and treated mice were injected with 3H‐thymidine prior to their sacrifice. Tissue samples from each mouse were processed for electron microscopy and autoradiography. The epithelium of the ventral prostate glands after testosterone treatment had four cell types: basal, intermediate, mitotic, and columnar. Intermediate and mitotic cells were most frequent during the second, third, and fourth day of androgen treatments. Basal and columnar cells were observed in normal, castrates, and androgen‐treated mice. The restitution of the epithelium included an initial phase of cell growth which was essentially comlete by the fifth day of hormone treatment. During the growth phase many basal and columnar cells synthesized DNA and became mitotic. Columnar cells increased their cell height and showed variable amounts or organelles and inclusions. The growth phase was followed by the secretory phase in which columnar cells contained abundant supranuclear organelles and inclusions and appeared as secretory cells much as those observed in normal prostate. The restitution process of the prostate glands of castrates was completed by the eighth day of hormone treatment.
Changes in the extracellular matrix components fibronectin and laminin during immune rejection of skeletal muscle
Authors: Gulati A. K. , Reddi A. H. , Zalewski A. A.
Published: February 2005

Extracellular matrix is known to play an important role during development and maintenance of various tissues. In the present study, changes in two extracellular matrix glycoproteins, fibronectin and laminin, were investigated in skeletal muscle undergoing immune rejection. Purified antibodies against fibronectin and laminin were used to analyze the matrix by indirect immunofluorescence at various intervals after transplantation of extensor digitorum longus muscle in rats. Fibronectin and laminin were localized in the pericellular basement membrane zone of the normal myofibers; however, the cytoplasm was devoid of both glycoproteins. Transplanted muscle grafts underwent a process of degeneration and then an initial regeneration during the first 7 days. This regeneration effort ceased with the onset of muscle rejection in 14‐day transplants. At this time, fibronectin was seen in the cytoplasmic region as well as the extracellular matrix of myofibers and myotubes. At later time intervals, an increased intensity of staining for fibronectin was seen throughout the rejected muscle. In muscle grafts undergoing regeneration but not rejection (i.e., nonantigenic grafts), such an increase in the presence of fibronectin was not seen (Gulati et al., 1982). The distribution of laminin did not change during the rejection process and was localized in the basement membrane zone of myofibers and myotubes, although the overall configuration of the basement membranes was deformed and collapsed. It appears that the basement membranes are resistant to degradation, and staining for laminin persists in rejected muscle. These results show marked changes in the extracellular matrix of muscle undergoing rejection. The appearance of fibronectin during the initial stages of muscle rejection may have a causal relationship to the process of immune defence mechanism; however, the exact role of fibronectin remains elusive.
Fine structural comparative peculiarities of the developing dipnoan dermal skeleton in the fins of Neoceratodus larvae
Authors: Géraudie Jacqueline
Published: February 2005

This study shows that actinotrichia are present in the growing fins of the dipnoan larvae Neoceratodus. They develop in advance of the camptotrichia, which will finally sustain the adult fin. Actinotrichia in dipnoan fins are similar to those already described in other osteichthyans. This feature strongly suggests the plesiomorphic character of the actinotrichia in the fish fins. In dipnoan, unlike other osteichthyan, actinotrichia are integrated in the growing camptotrichia and thus disappear in the adult fin. Consequently, only in dipnoan are actinotrichia a transitory dermal skeleton.
Growth of regenerating skeletal muscle fibers in cats
Authors: Maxwell Leo C. , Faulkner John A. , White Timothy P. , Hansen‐Smith Fay M.
Published: February 2005

Extensor digitorum longus (EDL) muscles of cats were grafted heterotopically or orthotopically, and either with or without prior denervation. The autografted muscles were studied at times from 4 to 518 days after grafting. Muscle weight, fiber cross‐sectional area, and ultrastructural, histochemical, and biochemical characteristics of regenerating muscle fibers were determined. Prior denervation reduced the mass of muscle at the time of grafting, but had no significant effect on the characteristics of the regenerating muscles. Orthotopic and heterotopic autografts achieved similar recovery of structure. Mean fiber area reached control values. Differentiation into fiber types occurred, but compared to control muscles, autografts had fewer Type I and Type IIA fibers. Electron microscopic analysis of regenerating muscle fibers revealed centrally located nuclei, but otherwise normal ultrastructure. The bimodal distribution of Z‐band width was consistent with differentiation into fiber types. Mean data of some morphological variables did not stabilize.
Regional differences of the proximal part of mouse epididymis: Morphological and histochemical characterization
Authors: Abou‐Haïla Aïda , Fain‐Maurel Marcelle‐Anne
Published: February 2005

Regional differences in the proximal part of mouse epididymis were reported to provide a morphological baseline for studies on functional zonation of this part that is critical in sperm maturation.

Macroscopical, histological, ultrastructural, and histochemical observations permitted us to subdivide this part into five segments, characterized by epithelial height, nuclear position, cytological and histochemical features of principal cells. Segment I corresponded to the initial segment previously described in rodents. Segment II differed from segment I by endoplasmic reticulum (ER) and dictyosomes aspect in principal cells, apical alkaline phosphatase and Ca2+‐dependent ATPase activities. Segment III was characterized by spermatozoa package, high content of cells in multivesicular bodies, mitochondria shape, complex interdigitating membranes, and strong periodic acid‐Schiff (PAS)‐positive cell border. Segments IV and V presented the same cytological features but differed by their esterase activity. In the principal cells of each segment, dense spherical concretions were scattered in ER caveolae.

Cells with apical nuclei were classified into two groups. The cells of the first group presented the same morphological and histochemical features as the adjacent principal cells and were scattered in the five segments (“apical cells”). The cells of the second group differed from the others by their goblet shape, a dense cytoplasm, and a high mitochondria succinate‐D activity. They presented different cytological and histochemical features depending on their localization in segments I (“narrow cells”), II (“prominent cells”), or III, IV, V (“mitochondria goblet‐cells”).

The possible relationships between epithelium structure and epididymal functions were herein discussed.
Quantitative analysis of rough endoplasmic reticulum approaches to the cell membrane in the secretory ameloblast of the rat incisor
Authors: McKee M. D. , Warshawsky H.
Published: February 2005

The distribution of approaches of rough endoplasmic reticulum to the cell membrane within the supranuclear region of the secretory ameloblast of the rat incisor was quantitated using a Zeiss MOP‐3. In ameloblasts cut in cross section, most of these approaches appear as circular profiles representing cross sections of elongated cisternae, which are aligned parallel to the long axis of the cell. Because of their position, orientation, and distribution of ribosomes, these approaches were consistent with the appearance of subsurface cisternae. Using cross‐sectioned ameloblasts, the lengths of apposed plasma membranes either between or within rows of cells were measured from electron micrographs. Along these lengths, matched approaches of rough endoplasmic reticulum from opposite sides of the apposed plasma membranes were counted. Approaches from either side that were unmatched were also counted. Thirteen percent of the approaches were matched between rows of ameloblasts, and 13.5% of the approaches were matched within rows, demonstrating no significant difference between the two sites. Furthermore, mathematical analysis showed that the theoretical probability of two approaches coinciding is 17%. The experimental values are not statistically different from the theoretical probability, and it is concluded that the matching of rough endoplasmic reticulum approaches to the plasma membrane, or subsurface cisternae, occurs at random.
Seasonal variations in pituitary thyrotropes of the hibernating bat Myotis lucifugus lucifugus: An immunohistochemical study
Authors: Anthony Edythe L. P. , Gustafson Alvar W.
Published: February 2005

Pituitary thyrotropes were identified throughout the year in the hibernating bat Myotis lucifugus lucifugus by means of light microscopic immunohistochemistry. These cells occupied a small proportion of the volume of the pars distalis (X = 1.36% in males; X = 1.52% in females) and exhibited a limited distribution pattern that was characteristic of all animals examined. Cells that were immunoreactive with an antiserum directed against the β subunit of thyroid‐stimulating hormone were most numerous in the median rostral and ventral regions; they were scarce or absent in the dorsal portion of the gland and in the extreme lateral wings. No significant seasonal variations were observed in this cell population in females. In males, however, immunoreactive thyrotropes occupied a significantly larger proportion of the pars distalis in June following arousal from hibernation than at other times of year. No evidence of involution was observed in these anterior pituitary cells in either males or females during hibernation.
Double immunocytochemical evidence for a clonal development of specific antibody‐containing cells in the rabbit spleen
Authors: van Rooijen N. , Kors N. , van Nieuwmegen R.
Published: February 2005

Rabbits were intravenously primed with the antigens human serum albumin (HSA) and bovine gamma globulin (BGG). The antigens were given simultaneously, or at an interval of 1, 2, or 4 days. After 2 months an intravenous booster injection with both antigens was given simultaneously. The localization pattern of anti‐HSA‐antibody‐containing cells and of anti‐BGG‐antibody‐containing cells in the spleen was determined during both the primary and secondary immune response. Anti‐HSA‐antibody‐containing cells and anti‐BGG‐antibody‐containing cells were not distributed randomly but, rather, were found in defined groups during the induction of an immune response. The most probable explanation for this grouping is that lymphoid cells, once triggered to proliferation by a particular antigen, show a clonal development in the spleen. During their proliferation and successive antibody formation, they migrate only slowly, so that they remain close together. Specific‐antibody‐containing cells were also detected in the popliteal lymph nodes and in the appendix of the rabbits.
Responsiveness of testis morphology to chemotherapy in childhood leukemia
Authors: Anelli Giuliana , Cozzi Giusi , Franchi Emilia , Parlavecchia Mariella , Chiara Franco , Masera Giuseppe , Camatini Marina
Published: February 2005

The appearance of seminiferous tubules and interstitial cells of children, aged 2.5 to 13 years, affected by acute lymphoblastic leukemia was analyzed in sections. The testicular biopsies were performed at the end of therapy (vincristine, prednisone, L‐asparaginase, 6‐mercaptopurine, intrathecal methotrexate), which was affected for the same period and at the same doses. Three age groups were considered (I, 2.5 to 5 years; II, 6 to 9 years; III, 12 to 13 years). Age groups I and II presented damage of some tubules (25–35%) and areas of degeneration. Histometric analysis performed for A type spermatogonial population gave a mean value corresponding to controls in age group I and a mean value significantly lower with respect to controls in age group II. Moreover, age group II presented a lack of increase in tubular cross section. These results suggest that there is a vulnerability both of whole tubules and of some areas of Sertoli cells and germ cells to cytotoxic‐induced damage. Leydig cells appear to be the cells least sensitive to drugs, and hormonal data indicate that the hypothalamic pituitary function appears to be intact, despite chemotherapy. Long‐term prospective studies of reproductive function in children receiving cancer chemotherapy are needed to determine the magnitude and duration of damage resulting from therapeutic treatment.
Germ cell degeneration in normal and microwave‐irradiated rats: Potential sperm production rates at different developmental steps in spermatogenesis
Authors: Johnson L. , Lebovitz R. M. , Samson W. K.
Published: February 2005

Germ cell degeneration in 14 normal and 14 microwave‐irradiated, adult (400–500 gm), Sprague‐Dawley rats was compared by evaluating potential sperm production rates at different developmental steps in spermatogenesis. Following 9 days of irradiation at 1.3 GHz (6 hours/day at 6.3 mW/gm using 1‐μsec pulsewidth at 600 pulses/second) or sham treatment, rats were killed at 6.5, 13.0, 26.0, or 52.0 days following treatment. Testes were perfused with 2% glutaraldehyde, embedded in Epon, and sectioned at 0.5 μm for morphometric analyses. Plasma LH and FSH concentrations were determined by radioimmunoassay from blood collected on the day of death. Considering nuclear size, percentage of nuclei in the parenchyma, and life span of different cells, potential daily sperm production was determined for type B spermatogonia, preleptotene or pachytene primary spermatocytes, or spermatids with round nuclei. No differences (P > .05) in parameters tested were found among time periods following irradiation. With the possible exception of sperm production per testis (P < .05) based on pachytene spermatocytes, microwave irradiation had no effect on the parameters evaluated. No degeneration was detected in spermatogenesis when potential sperm production rates were determined either from type B spermatogonia to spermatids or from type B spermatogonia to a posttesticular approximation of sperm production rate. Thus, it appears that regulation of sperm production rates must take place during spermatogonial mitoses, since once the number of type B spermatogonia is determined, there is essentially no subsequent alteration in sperm production potential in normal or irradiated adult rats.
Morphology and ultrastructure of the distal airway epithelium in the guinea pig
Authors: Davis M. Lynn , Lewandowski Jan , Dodson Ronald F.
Published: February 2005

The distal airways, defined anatomically as the region of the respiratory system including the terminal bronchioles through alveoli, were characterized in the guinea pig by means of light microscopy and by both scanning and transmission electron microscopy.

The epithelium of the terminal bronchioles was comprised of two cell types. Ciliated cells were cuboidal and contained long thin microvilli, ellipsoid mitochondria, and both rough and smooth endoplasmic reticulum. Nonciliated (Clara) cells were dome‐shaped and usually protruded into the bronchiolar lumen. Numerous large mitochondria, granules of varying density, and crystalloid inclusions were notable in nonciliated cells.

Respiratory bronchioles were characterized by a smooth‐surfaced, low cuboidal epithelium. The cells in this region contained the crystalloid material found in terminal bronchioles, numerous large mitochondria, lysosomelike inclusions, and unusual tubular structures arranged in a matrix.

The epithelium became progressively squamous toward the alveolar duct, where transition from bronchiolar cells to pneumocytes occurred. Transitional zones consisted of cells which, in addition to the above‐mentioned structures, contained inclusions with internal laminations. These inclusions were structurally similar to the lamellar bodies observed in typical type II pneumocytes of the alveoli.

The epithelium of both the alveolar ducts and alveoli was composed of type I and type II pneumocytes. Classical type I pneumocytes were squamous and very similar in cytoplasmic characteristics to the endothelial cells of the adjacent capillaries. Type II pneumocytes were characterized by the presence of lamellar bodies and numerous mitochondria.
Lymph node involvement in a humoral immune response
Authors: Geldof A. A. , van der Ende M. B. , Langevoort H. L.
Published: February 2005

Mice were primed subcutaneously in the hind footpads with horseradish peroxidase (HRP) and boosted intravenously 10 weeks later. The appearance of cells with cytoplasmic anti‐HRP antibody was studied in several lymph nodes. It appeared that following intravenous boosting antibody‐forming cells appeared in significant numbers in the popliteal, the lumbar, and (in some animals) the sciatic lymph nodes exclusively. In the other lymph nodes examined specific antibody‐forming cells were observed only occasionally. By subcutaneous injection of Evans blue in the hind footpads it was shown that the subcutis of the hind footpads of these animals is drained by the popliteal lymph nodes, the lumbar lymph nodes, and (to a lesser degree) the sciatic lymph nodes. The presence of trapped immune complexes within lymph node germinal centers was confined to these three nodes.

Based on these findings, it is concluded that specific antibody‐forming cells during the secondary response in these mice are induced exclusively in the lymph nodes draining the site of primary immunization.
Catecholamine synapses and contents in the paraventricular hypothalamic nucleus and nucleus tractus solitarius of DOCA‐salt hypertensive rats
Authors: Hwang Bang H. , Chiueh Chuang C. , Severs Walter B.
Published: February 2005

Central catecholamine (CA) neurons in the nucleus tractus solitarius (NTS) and paraventricular hypothalamic nucleus (PVN) were studied in Wistar rats that had been unilaterally nephrectomized. The experimental animals were then treated with deoxycorticosterone acetate (DOCA) and salt water. The control animals were treated with the vehicle and tap water. Blood pressure of animals 4 weeks after DOCA/salt treatment was significantly elevated when compared to control rats. Morphologically, CA terminals showed no noticeable changes in the DOCA/salt hypertensive rats. Furthermore, the density of CA terminals either in the NTS or in the PVN of the DOCA/salt hypertensive rats was not statistically different from that of normotensive controls, suggesting that salt does not cause lesions or destruction of CA terminals. However, an extensive electron‐microscopic morphometric analysis indicated that there was an enhancement of CA synaptogenesis (expressed by increased synaptic frequency among all CA boutons labeled with 5‐hydroxydopamine) in the PVN, but not in the NTS of DOCA/salt hypertensive rats. In addition, the high‐performance liquid chromatography revealed decreased CA contents in the PVN, but not in the NTS, of DOCA/salt hypertensive animals. Since synapses are primary sites for neurotransmitter release, the above results collectively suggest that more CA synapses formed in the PVN may reflect a net CA release from CA terminals resulting in the decreased CA content in the axonal terminals. Such an increased CA release and enhanced CA synaptogenesis may consequently enhance CA function in the PVN of hypertensive rats 4 weeks after DOCA/salt treatment, and relate to the development and/or maintenance of hypertension in the DOCA/salt rats.
Distribution of plasmelemmal vesicles on arterial endothelial surface as determined by freeze cleavage
Authors: Jan Kung‐Ming
Published: February 2005

The freeze‐fracture technique was used to study the density and distribution of plasmalemmal vesicles at the endothelial surface of canine carotid arteries. The fractured surface of the endothelium can be divided into areas with vesicles (Aves) and areas without vesicles (Anves), the latter being located at the parajunctional zone. With morphometric analysis, Aves and Anves were found to be 75% and 25% of the endothelial surface, respectively. The average width of Anves (distance from the intercellular cleft) is approxmately 0.4 μ. In Aves, the density of vesicles is 120 μm−2, and approxmately 16% of Aves is covered by the vesicle orifices. The tight junctions appear as long and straight strands, 8–9 nm in width. The number of the strands varies from one to five. The gap junctions consist of closely packed particles 9–10 nm in size which form patches or plaques from 80 to 800 nm in size. These findings provide the quantitative information needed for the theoretical modeling of transendeothelial vesicular transport of macromolecules.
Morphology of the erect glans penis in rats under various gonadal hormone conditions
Authors: Sachs Benjamin D. , Glater Glen B. , O'Hanlon Joyce K.
Published: February 2005

The scanning electron microscope (SEM) was used to compare erect and nonerect penile glandes of gonadally intact Norway rats (group I) and of castrated rats exposed to the following hormonal conditions: maintained with testosterone (T)‐filled Silastic capsules implanted subcutaneously (group T); maintained with implants of estradiol (E) for 8 or 12 days (group E1); maintained with E implants for 10 weeks (group E10); maintained with E implants for 9 weeks, then injected daily with testosterone propionate for 8 or 17 days (group E/T). As in previous SEM depictions of nonerect glandes of intact rats, spines projected toward the base of the glans at a shallow angle from the sulci of deep epithelial folds. In contrast, the folds on erect glandes of groups I and T were completely smoothed, and the spines were themselves erected. The penile cup formed at the distal end of the erect glans also contained spines; these were centrifugally directed at the rim and centripetally directed on the inner surface of the cup. The glandes of group E1 males were similar to those in groups I and T, with the spines showing no disorientation. Males in group E10 lacked spines in the cup and along most of the shaft of the glans, but erection revealed many sharp spines just proximal to the cup and on its rim. In group E/T, no papillae were detectable on the nonerect glandes, but erection revealed many small rounded papillae on the shaft and within the cup. The erection of the spines that occurs on the shaft and in the cup of the erect glans may facilitate previously proposed functions on the spines, including vaginal and cervical stimulation and removal of the copulatory plug. Our perfusion method may also facilitate estimation of the number, size, distribution, and hormonal sensitivity of penile papillae.
Endocrine cell populations in the colon and rectum of cat, dog, and monkey: Fine structure, immunocytochemistry, and distribution
Authors: Peranzi Gabriel , Lehy Thérèse
Published: February 2005

Comparative and quantitative ultrastructural studies of endocrine cells from the large bowel of European cat, beagle dog, and the monkey Callitrix jacchus were performed. The cat and monkey exhibited a roughly similar distribution of colonic endocrine cells with a frequency increasing toward the distal colon. On the contrary, the highest endocrine cell frequency in the dog colon was found in the cecum. In the dog and monkey, enterochromaffin (EC) cells were predominant in all segments. In the cat, non‐EC cells were predominant in the proximal colon. For each colonic segment, relative percentages of EC and non‐EC cells appeared on the whole to be roughly stable between individuals of the same species. Three subtypes of EC cells were distinguished in each species. Non‐EC cells were characterized by large variation in size and electron densities of their granules: Mean granule size per cell extended from 210 to 850 nm in cat, 310 to 770 nm in dog, and 130 to 470 nm in monkey. In each species, statistical analyses indicated that the non‐EC cell population was composed of two or more subpopulations. Some similarities were found between colonic endocrine cells of the monkey and man, whereas obvious differences appeared between the two carnivorous mammals. Immunocytochemical studies demonstrated the presence of cells containing enteroglucagon, somatostatin, or a pancreatic polypeptidelike substance in the colon of the monkey and the rectum of the three mammals. Correlative immunocytochemical and ultrastructural studies showed that the three kinds of immunostained endocrine non‐EC cells in each species had rather round granules, with great electron densities. Some subpopulations, morphologically distinguished, did not react to any of the antisera used. This suggests either the existence of secretory cycle in some endocrine cells or, perhaps, the presence of peptides still unknown in this part of the gut.