摘要:

AbstractMacrophages are common in rat testicular interstitial tissues. Interstitial‐tissue macrophages were characterized using ultrastructural, cytochemical, immunologic, and autoradiographic methods. Testicular interstitial‐tissue macrophages have a single indented nucleus, paranuclear Golgi complex, rough endoplasmic reticulum, coated vesicles, and numerous heterogeneous lysosomal vacuoles. Long filopodia and lamellopodia extend from the macrophage cell body into the lymphatic space. Macrophages are usually found adjacent to Leydig cells, and numerous Leydig cell processes are inserted into coated membrane invaginations on the macrophage surface. Secondary lysosomal vacuoles in the macrophage are cytochemically reactive for acid phosphatase (trimetaphosphatase) and aryl sulfatase. Testicular interstitial macrophages are endocytically active, avidly incorporating exogenously administered trypan blue dye and monomeric plutonium‐citrate. Macrophages were isolated from the testes by allowing them to adhere to glass. The isolated macrophages were found to have receptors for the Fc portion of immunoglobulin G on their surface. The association of macrophages with Leydig cells and their endocytic and immunologic activity suggests that these cells may play an important role(s) in testicular functions. In addition, the ability of these cells to incorporate exogenous materials indicates that they could have a role in gonadal toxicity reac

ISSN:0002-9106    

DOI:10.1002/aja.1001680102

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

年代:1983

数据来源: WILEY

摘要:

AbstractCircadian rhythmicity in cell proliferation was studied by several cytokinetic techniques in 8‐week‐old CD2F1and Swiss male mice. In separate experiments on four different dates, subgroups of six or seven mice (fed ad libitum and standardized to 8 hours light alternating with 16 hours of darkness) were killed at 3‐hour intervals over a period of 24–48 hours. Cosinor analyses were used to determine the parameters of circadian periodicity in the data. Flow cytometric (FCM) analyses of DNA synthesis in tongue and stomach were compared with estimates of tritiated thymidine (3HTdR) incorporation into the DNA in these tissues. Circadian variation in tongue epithelium was reproducible in phasing and in range‐of‐change (100–140%) in seven 24‐hour studies. The proportion of cells in G1 and G2 in tongue epithelium also demonstrated a circadian periodicity. When DNA synthesis in stomach was analyzed by the two methods, the results were entirely different and thus not comparable. The circadian rhythms in3HTdR uptake agreed with those reported previously, but results of analyses by FCM were less certain, since epithelium of this organ could not be analyzed separately. Circadian rhythms were detected by FCM in G1, S, and G2M in Ehrlich ascites carcinoma (EAC). The mitotic index of this tumor varied with a circadian periodicity similar to that of the FCM‐derived rhythm in G2M. This study validates the reliability of older techniques, such as3HTdR uptake and mitotic indices, and suggests that circadian rhythms can be important in studies of cellular pro

ISSN:0002-9106    

DOI:10.1002/aja.1001680103

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

年代:1983

数据来源: WILEY

摘要:

AbstractMuscle spindle density (number of spindes per gram of muscle) of all 29 muscles of the forearm and leg of the domestic pigeon was evaluated by counting receptors in van Gieson‐stained serial cross sections. Extra‐ and intrafusal fiber‐type profiles were determined from histochemical preparations. Muscles of the leg had on the average significantly more avian slow‐twitch oxidative extrafusal fibers (22.5 vs. 0.8%) and slower contraction times than muscles of the forearm, but fiber‐type profiles and gross actions of muscles showed no consistent relation to the relative abundance of receptors. Differences in intrafusal fibertype composition among spindles were sought because of their potential effect on the quality of the afferent discharge. The number of intrafusal fibers per spindle was on the average significantly less (4.57 vs. 5.99) in the muscles of the leg than in those of the forearm; and of spindles with the same number of intrafusal fibers, those in the leg had smaller periaxial spaces. Distribution of intrafusal fiber types identified with the myofibrillar adenosine triphosphatase reaction differed among spindles of varying sizes. An acid‐ and alkali‐labile type occurred most frequently (P = 0.05) in spindles with one to three intrafusal fibers, and an acid‐labile and alkali‐stable type was most often seen (P = 0.05) in spindles with 4 to 7 intrafusal fibers. The smaller receptors were more abundant in the leg, while the larger ones were about equally distributed between the two extremities. Muscle fibers with dimensions that sometimes approached small extrafusal fibers were present in about 3% of the axial bundles examined, most of them in the forearm. The selective morphological variation of avian muscle spindles may represent the structural basis for qualitatively different afferent discharges that relate to the characteristic types of locomotion served by th

ISSN:0002-9106    

DOI:10.1002/aja.1001680104

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

年代:1983

数据来源: WILEY

摘要:

AbstractElectron microscopic and histochemical procedures were used to describe iron loading in the normal liver of parasitic adult sea lampreys,Petromyzon marinusL. Ferric iron is present in large quantities as ferritin in the cytoplasmic matrix, in hemosiderin granules, and in large vacuoles of hepatocytes. Ferritin is also found in the lateral intercellular space, in the perivascular space, and in the sinusoidal lumen. Large crystals in the cytoplasmic and nuclear matrices of some hepatocytes likely represent excessive aggregations of ferritin molecules. Ferrous iron is localized at the lateral cell membrane and vacuolar membranes of hepatocytes. Iron accumulation is less significant in Kupffer cells which are present in small numbers. The relationship of iron loading in the adult lamprey liver to the sanguivorous diet, the rate of erythrophagocytosis, the absence of bile ducts and canaliculi, and the nature of iron‐binding proteins in the plasma are considered. Emphasis is placed on the similarity of the above morphological findings to those resulting from experimentally induced and pathological states of iron loading in other vertebrates, and on the potential use of the lamprey as a model for studying iron loading in the vertebrate live

ISSN:0002-9106    

DOI:10.1002/aja.1001680105

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe volumes of the major tissue compartments, vascular space, interstitial space, and luteal cells, in the corpus luteum (CL) of 16‐day pregnant rats were determined morphometrically after different fixation procedures. Ovaries were fixed by perfusion at physiologic pressures (PF), by immersion directly in fixative (IF), by immersion after clamping blood vessels to prevent escape of blood (IFC), or by immersion after administration of heparin to prevent blood clotting (IFH). Three CL in each of eight ovaries were examined for each fixation method. Total volumes were significantly larger in CL fixed by PF and IFC, and approximated physiologic volumes as assessed from frozen ovaries. Perfusion‐fixed CL had significantly larger vascular and interstitial spaces and smaller cell volumes than immersion‐fixed CL. Capillary surface area varied significantly between the four groups in accordance with absolute volume of vascular space. Estimated numbers of endothelial cells and amounts of connective tissue differed significantly, presumably due to difficulties in identifying these components in immersion‐fixed CL with collapsed vessels. The fixation methods used caused substantial fluid shifts between the three major compartments. A theoretical approach for considering these shifts and the likely physiologic situation was de

ISSN:0002-9106    

DOI:10.1002/aja.1001680106

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe present study deals with the functionally enigmatic “synaptic” ribbons and spherules of guinea pig pinealocytes. Whereas the ribbons have been shown to exhibit a 24‐hr rhythmicity with low numbers during the day and high numbers at night, very little of a definitive nature is known about the spherules. Sixteen male guinea pigs of the Hartley strain were perfusion fixed, 8 between 0900–1100 hr, and 8 between 2100–2300 hr. The ribbons and spherules were counted in the pineal parenchyma of the proximal, intermediate, and distal regions. In confirmation of earlier studies, it was found that “synaptic” ribbons are equally abundant in the proximal, intermediate, and distal regions of the gland, during both the day and the night, and that they increase significantly in number at night when compared with daytime values. The spherules, by contrast, are more abundant proximally and are present in greater numbers during the day than at night. As ribbons and spherules are usually not found in one and the same pinealocytic profile, and based on previous electrophysiological studies, it is proposed that the ribbons are morphological markers of nocturnally active pinealocytes, whereas spherules characterize diurnally active

ISSN:0002-9106    

DOI:10.1002/aja.1001680107

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

年代:1983

数据来源: WILEY

摘要:

AbstractThis study correlates the morphological and biochemical events during the accumulation of hepatic lipids in diabetic rats in response to insulin treatment and a high‐carbohydrate, fat‐free diet. Alloxan‐diabetic rats were fed a high‐carbohydrate, fat‐free diet and treated with insulin for 12, 36, or 60 hr or 4.5 or 6.5 days. Samples of livers were obtained for determination of malic enzyme activity and the histochemical demonstration of lipids. An increased accumulation of hepatic lipids, although delayed, was observed following insulin treatment of diabetic rats fed the special diet. Small lipid droplets were visible after 36 hr of treatment, which later increased and coalesced into larger droplets present in all hepatocytes. Maximal accumulation was observed at 4.5 days of treatment. These changes were paralleled by an increase in the activity of hepatic malic enzyme. By 6.5 days of treatment, the lipid content of the hepatocytes had decreased and a periportal pattern was discernible. In contrast, malic enzyme activity continued to increase through 6.5 days of treatment. By comparison, no hepatic lipid accumulation occurred in regular chow‐fed diabetic rats receiving insulin treatment or in diabetic rats placed on the special diet alone. These results suggest that the combination of insulin treatment and a high‐carbohydrate, fat‐free diet caused an imbalance in the production and mobilization of

ISSN:0002-9106    

DOI:10.1002/aja.1001680108

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

年代:1983

数据来源: WILEY

摘要:

AbstractSertoli cells of the ground squirrel (Spermophilus lateralis), a seasonal breeder, were examined by light and electron microscopy and their structure, particularly the organization of the cytoskeleton, was related to events that occur in the seminiferous epithelium during spermatogenesis. Among the events considered and described are the apical movement of elongate spermatids, withdrawal of residual cytoplasm from germ cells, transport of smooth endoplasmic reticulum (SER) between the base and apex of the Sertoli cells, and sperm release. These events are dramatically evident in this species because the seminiferous epithelium is thin, i.e., there are few germ cells, and both the germ cells and Sertoli cells are large.Sertoli cells of the ground squirrel have a remarkably well developed cytoskeleton. Microfilaments occur throughout the cell but are most evident in ectoplasmic specializations associated with junctions. Intermediate filaments occur around the nucleus, as a layer at the base of the cell, and adjacent to desmosome‐like junctions with germ cells. Intermediate filaments, together with microtubules, are also abundant in regions of the cell involved with the transport of SER, in cytoplasm associated with elongate spermatids, and in processes that extend into the residual cytoplasm of germ cells. Our observations of ultrastructure are consistent with the hypothesis that Sertoli cell microtubules are involved with the movement of germ cells within the seminiferous epithelium, and further implicate these structures as possibly playing a role in the retraction of residual cytoplasm from germ cells and the intracellular transport of SER. The abundance and organization of intermediate filaments suggest that these cytoskeletal elements may also be involved with events that occur during spermatogenesi

ISSN:0002-9106    

DOI:10.1002/aja.1001680109

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

年代:1983

数据来源: WILEY

摘要:

AbstractStudy of Sertoli cells of the ground squirrel provides a unique opportunity to examine cell structure and function. The cells are large, have an elaborate cytoskeleton, and undergo dramatic changes in organization during spermatogenesis. Microtubules (MTs) are prominent elements of the cytoskelton and appear to be associated structurally with many of the events that occur during sperm production. To investigate the function of MTs, animals were injected subcutaneously with colchicine, and their seminiferous epithelia examined by light and electron microscopy. Some animals were injected with 30–80 mg of the drug per kg body weight and sacrificed 3 to 5 hr later. Others were given 0.3 mg/kg/day for 6 days and processed on day 7. Virtually no MTs were seen in Sertoli cells after short‐term treatments, and their numbers were greatly reduced after the long‐term injections. Intermediate filaments were very evident throughout the cytoplasm of treated cells, particularly in the short‐term studies. Moreover, a close association of some of these filaments with centrioles was observed. In all cases, elongate spermatids which normally move apically did not do so. Indeed, some spermatids appear to have been pulled to a basal position after having moved apically prior to treatment. Also, smooth endoplasmic reticulum (SER) accumulated basally in the Sertoli cell, unlike controls, and the acrosomes of late spermatids developed abnormally or did not complete their shape changes. Cell junctions appeared normal and sperm release was observed. In conclusion, our data suggest that Sertoli cell MTs are necessary for the normal development and translocation of spermatids in the seminiferous epithelium and are involved with positional changes in Sertoli cell SER. They do not appear essential for the maintenance of cell ju

ISSN:0002-9106    

DOI:10.1002/aja.1001680110

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe distribution of cells displaying glucagonlike or gastric inhibitory polypeptide (GIP)‐like immunoreactivity was examined in the pancreatic islets and gastrointestinal tracts of rats, dogs, and humans. A‐cells in the pancreatic islets in all three species were stained by antisera having regional specificity for pancreatic‐type glucagon, gut‐type glucagon (glicentin), or GIP. Oxyntic A‐cells of the gastric mucosa in dogs and humans also were stained comparably by these three antisera. In contrast, the K‐ and L‐cells in the intestinal mucosa of those species were stained only by antisera capable of reacting with GIP or gut‐type glucagon, respectively. Tests of antibody specificity showed that the GIP antiserum did not cross‐react with either pancreaticor gut‐type glucagon. Likewise, the glucagon antisera showed no cross‐reactivity with GIP. Hence, these findings suggest that pancreatic and gastric A‐cells contain a peptide with GIP‐like immunoreactivity distinct from glucagon or glicentin per se. Although the exact basis of the GIP‐like immunostaining of A‐cells is unknown, it may be due to the presence of a glucagon precursor sharing certain amino‐acid sequences with GIP. This hypothesis is consistent with several recent investigations showing that the processing of proglucagon molecules dif

ISSN:0002-9106    

DOI:10.1002/aja.1001680111

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

年代:1983

数据来源: WILEY