bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractVascularization 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

AbstractEffects 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

AbstractPlain 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

AbstractThe 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

AbstractExtracellular 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

AbstractThis 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

AbstractExtensor 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

AbstractRegional 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

AbstractThe 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

AbstractPituitary 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

AbstractRabbits 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

AbstractThe 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

AbstractGerm 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

AbstractThe 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

AbstractMice 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.