摘要:

AbstractIn the dorsal epidermis of both C57BL/10J (black,BB) and C57BR/cdJ (brown,bb) mice, the number of melanocytes positive to the dopa reaction (melanocyte population) increases from birth to day 3 or 4, and then gradually decreases. However, the number of melanoblasts plus melanocytes positive to the combined dopa‐premelanin reaction (melanoblast‐melanocyte population) remains constant until day 3 or 4 and then decreases in the two strains. Despite the similarity of the developmental dynamics in both black and brown mice, there is a significant difference in the number of differentiated melanocytes. Melanocytes are more numerous and more dopa‐reactive in brown mice than in black. The maximal density of the melanoblast‐melanocyte population on day 3 or 4 does not differ in brown and black mice. Moreover, the maximal density of the melanocyte population in brown epidermis does not differ from that of the melanoblast‐melanocyte population of both brown and black. These results indicate thatballele, when homozygous, enhances the differentiation of epidermal melanoblasts by inducing high tyrosinase

ISSN:0003-276X    

DOI:10.1002/ar.1092090402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractIn the pharyngeal pad on the roof of the anterior pharynx ofCarassius carassiustwo types of thin striated muscle fibers (1.5‐10 μm in diameter) were found. No pattern was discerned in the orientation of muscle fibers which form a loose tissue as a whole. One of them (Z fiber) is characterized by position of triads at the level of Z lines, and in the other type (A‐I fiber) they were seen at the junction of the A and I bands.Three types of intermyofibrous junction are noted between muscle fibers of the same type or between those of different types. The first type possesses ultrastructural features such as a uniform intercellular space about 90 nm which contains the basal lamina, a dense mat of the filamentous material on the sarcoplasmic aspect of the cell membrane, and a connection of myofibrils with the dense layer by thin I band filaments. The second type resembles the previous type but is distinguished from it by the lack of myofibrillar association. The third type is the nexus or gap junction. Intermyofibrous junctions of the second type are most frequently encountered (82%). Those of the first type are less frequently seen (15%), whereas the third type junctions are far less frequently seen (3%).Nerve endings at the neuromuscular junction of both types of muscle fiber contain numerous small clear vesicles suggesting their cholinergic na

ISSN:0003-276X    

DOI:10.1002/ar.1092090403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe distribution of intravascularly administered ferritin was examined in histological sections of femurs from 2‐day‐old chicks. The ferritin was seen in the mineralized portion of the bone as well as in the vessels 5 minutes after injection into the external jugular vein but was essentially absent 4 hours after injection. The concentration of ferritin in the vessels appeared to increase from the endosteal to the periosteal surface. In the mineral the ferritin appeared to move as a front roughly parallel and distal to the canals. A scheme for the movement of fluid and associated material through the mineralized portion of chick bone is presented that suggests that the driving force for the bone fluid is attributable to pressure differentials between adjacent canals. This differential is due to the geometry of the canals and increases as the angle of the canal relative to the endosteal surface decrea

ISSN:0003-276X    

DOI:10.1002/ar.1092090404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe vascularity and the density of arteriovenous anastomoses (AVAs) were studied in the skin of the domestic fowl by using vascular injections and histological sections. The density of AVAs and associated blood vessels were low in the wattles and in the thoracic skin (five to 23 AVAs per cm2and five to 14 AVAs per cm2, respectively), whereas the eyelids were highly vascular and contained many AVAs (170‐172 AVAs per cm2). It is suggested that the blood vessels in the eyelids are important in the temperature regulation of the eye and that AVAs in the thoracic skin may contribute to the control of blood flow through the brood patc

ISSN:0003-276X    

DOI:10.1002/ar.1092090405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe integument of larval, parasitic adult, and upstream‐migrant lampreys (Petromyzon marinus) was examined for iron deposition using light microscopic histochemistry and routine and histochemical procedures in the electron microscope. Ferritin particles, representing ferric iron, are present throughout most of the cytoplasmic matrix and within dense granules and vacuoles of epidermal mucous cells, but are not located in skein or granular cells. These particles are abundant in mucous cells of the dorsal surface but not the ventral surface and are more concentrated in adult lampreys compared to larva. Histochemistry revealed only sparse amounts of ferrous iron. Iron is not present in the dermis but is found in adipocytes of a subcutaneous layer. The deposition of integumentary iron is discussed with reference to body pigmentation and excretion of this meta

ISSN:0003-276X    

DOI:10.1002/ar.1092090406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe distribution of lysozyme in the endocervix of estrous, pseudopregnant, and ovariectomized rabbits was studied using two different immunocytochemical techniques—the unlabeled antibody enzyme method of Sternberger et al. (1970) and the peroxidase‐labeled antibody method of Taylor and Burns (1974). With both procedures, a fine immunostaining precipitate was seen over the entire area of basal mucous granules, while immunodeposits were coarser and mostly located in the outer zone of central and apical granules. A nonspecific staining was noted when tissues were reacted with peroxidase‐antiperoxidase complex alone. This troublesome artifact was abolished by preincubating tissues with human IgA. This step did not affect the specific immunostaining for lysozyme yet nonspecific staining was absent from specificity and method controls carried out for both immunocytochemical procedures. The presence of high levels of lysozyme in the endocervical epithelium of estrous rabbits was also confirmed in enzymatically isolated endocervical epithelia using the lysoplate method of Osserman and Lawlor (1966). Mucous granules and immunostainable intracellular lysozyme were abundant during estrus, decreased during early pseudopregnancy, and were absent after longterm ovariectomy. However, they were restored by the administration of estradiol (5 μ/12 hours/10 days) to ovariectomized animals. These data indicate a common hormonal regulation and secretory mechanism for endocervical mucous glycoproteins and ly

ISSN:0003-276X    

DOI:10.1002/ar.1092090407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractLysozyme is a bacteriolytic enzyme component of the secretory granules of endocervical mucous cells. In order to study the subcellular distribution of this enzyme in specific cell populations, endocervical cells from estrous and 5‐day pseudopregnant rabbits were separated by unit gravity sedimentation. The application of this technique to pronase‐dispersed endocervical cells from estrous rabbits resulted in the isolation and enrichment of two mucous cell types that were distinguished morphologically into type I and type II cell populations. Lysozyme was identified in both cell types, using an unlabeled antibody enzyme method, and the degree of staining paralleled the number of mucous granules. In the absence of estrogen dominance in 5‐day pseudopregnant rabbits, there was a 50% reduction in the number of mucous cells with a concomitant reduction in both the number of secretory granules per cell and the intracellular concentration of lysozyme. In the absence of ovarian steroid hormones, i.e., 15–16 weeks after ovariectomy, endocervical cells were devoid of secretory granules and lysozyme staining was negative. Enriched populations of endocervical cells represent a potential experimental model for studying the hormonal role in the regulation of lysozyme synthesis by specific cell popu

ISSN:0003-276X    

DOI:10.1002/ar.1092090408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

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

ISSN:0003-276X    

DOI:10.1002/ar.1092090409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

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 a

ISSN:0003-276X    

DOI:10.1002/ar.1092090410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

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 mitocho

ISSN:0003-276X    

DOI:10.1002/ar.1092090411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY