摘要:

A comparative study of the endocrine pancreas was carried out in genetically diabetic (db) mice and in mice with streptozotocin-induced (Sz) diabetes over a 12-week period of pronounced diabetes. Mice were examined at 9, 12 and 21 weeks of age. Plasma and pancreatic levels of immunoreactive insulin and immunoreactive glucagon were measured in both experimental animal models, and the biochemical data obtained were correlated with ultrastructural observations on the endocrine pancreas. Both pancreatic and plasma immunoreactive insulin levels were severely depressed in all Sz mice. Although pancreatic immunoreactive insulin concentrations in db mice were consistently lower than control values, these animals displayed a hyperinsulinemia which gradually dropped to control levels by 21 weeks. Pancreatic immunoreactive glucagon levels in 12- and 21-week-old db mice were markedly lower than those found in either control or in Sz mice. However, both db and Sz mice in all age groups exhibited a marked and persistent hyperglucagonemia. Pancreatic islet tissue was examined concurrently in control and experimental animals. The ultrastructural changes occurring in the endocrine cells are reported and discussed with regard to the pancreatic and plasma levels of the hormones presently monitored and in light of other recent studies on these animal models.

ISSN:1422-6405    

DOI:10.1159/000145690

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

We injured false tendons of the dog heart and examined the intercalated disks (ID) to locate the site of cardiac cell uncoupling. We put the preparations at two calcium concentrations: Ca++-free solution (no healing) and [Ca++]=5.4 mM (‘healing-over’). They were studied immediately, and 1 h, after the injury. We examined the diffusion of Procion yellow from the cut end and measured the relative area of nexus. After the ‘healing-over’ we found that the ID linking damaged and undamaged cells were the barrier to the diffusion of the dye, and that these ID underwent an exponential decrease in the nexal area (time constant 1.5 h). On the other hand, the next ID (i.e. the other extremity of the same cells) kept the nexal area they had in the unhealed condition. These facts indicate that the true uncoupling site is the ID that separate damaged from undamage

ISSN:1422-6405    

DOI:10.1159/000145691

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

A quantitative ultrastructural study on the prolactin (PRL) cells of normal male mice was correlated with serum PRL immunoassay determination at different times in a circadian period. Significant time fluctuations in the percentages of cytoplasmic volume occupied by most of the organelles, as well as cyclic variations in serum PRL concentrations were detected. The endoplasmic reticulum appeared more developed at the beginning of the light period, suggesting a higher synthesis of PRL at this time. The evaluation of the Golgi complex and the secretory granules would indicate that packaging of secretory material and storing of PRL granules ccurred mainly during the second half of the light period. This coincided with the lowest values in serum PRL concentration and an increment in mitochondrial mass. The highest emiocytotic activity together with a diminution of total secretory granules were found during the dark period. The peak of PRL serum concentration was also present in this phase, but some hours later. Evaluation of microtubules and lysosomes gave some additional information. The results are in keeping with those from some biochemical investigations performed in mice and rats, but are not in agreement with others. The importance of a morphometric approach to evaluate and corroborate the immunoassay methods in the study of cyclic hormone secretion is emphasized.

ISSN:1422-6405    

DOI:10.1159/000145692

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Serial paraffin sections (mostly stained with hematoxylin and eosin) of 52 human embryos at stages ranging from 13 to 20 (approximate ovulation age of 5–8 weeks) were examined. The first sign of definitive blood vessels was found to be localized in the apical incisure of the heart of an embryo at stage 14. Blood vessels of this kind closely resembled ‘blood islands’ in appearance, being composed of primitive erythroblasts surrounded by an outer layer of endothelium. At stage 16, a funnel-like invagination of the endothelium was recognized in the posterior wall of the sinus venosus. This structure was considered to represent one of the cardiac veins (probably the middle cardiac vein). A faint endothelial sprout of the left coronary artery was detected at stage 18, while the right one was observed later, at stage 19. Finally, at stage 20, both of the coronary arteries invariably existed with a covering of mesenchymal

ISSN:1422-6405    

DOI:10.1159/000145693

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Female Holtzman rats, weighing about 40 g, were given one of each of the following treatments: (a) 6% protein diet ad libitum throughout; (b) 6% protein diet for 2 weeks followed by 25 % protein diet ad libitum for 2 weeks; (c) 25 % protein diet fed in amounts isocaloric with treatment (a) and (d) 25% protein diet ad libitum throughout. These treatments were applied from weaning (21 days) to 49 days of age. Selected pairs of treatments were compared in order to elicit the influences of protein-calorie malnutrition, malnutrition recuperation, and protein deficit on both the absolute and relative weights of the following head components: skin (plus subcutaneous adipose tissue), muscular mass, eyeballs, skull, and encephalon. DNA and total protein concentrations in encephalon and muscle were also measured. The head components were classified into stables, for which growth decreased less than that of the head as a whole, and variables, for which growth decreased more than that of the head as a whole. The eyeballs, encephalon, and skull behaved as stable components, whereas the muscular mass and skin did so as variable components. The well-known modifications in the craniofacial growth pattern evoked by nutritional deficiencies were explained by the different reactions shown by the encephalon, functionally associated with the neurocranium, and the skeletal muscles, functionally associated with the masticatory apparatus. The changes observed in DNA concentration suggest that protein deficit delayed muscle growth through a decrease in cell size rather than a decrease in cell number in the muscular fibre.

ISSN:1422-6405    

DOI:10.1159/000145694

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The various colours produced by the MBTH reaction in collagen fibres of frozen tissue slices are caused not only by free aldehyde groups but also by cross-links up to the desmosin stage. The evidence is based on the colours produced by chemical models of the cross-links.

ISSN:1422-6405    

DOI:10.1159/000145695

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The uptake and retention of radiolabelled dihydrotestosterone or one of its metabolites by both the male and female reproductive organs were examined in the baboon. 2 male and 2 female baboons were injected intravenously with 1 μg/kg body weight of 3H-dihydrotestosterone and 2 animals, 1 male and 1 female, were injected with both labelled and 100 μg/kg body weight of radio-inert dihydrotestosterone. 1.5 h after the injections, the animals were sacrificed and the uterus, cervix, vagina, uterine tube, labia minora, seminal vesicles, prostate, ductus deferens, and prepuce were removed and treated for autoradiography. The stratified squamous epithelia of the cervix, vagina, labia minora and prepuce demonstrated uptake of label in the germinative, but not in the superficial, cell layers. The columnar cells lining the uterine tube and cervical glands, but not the uterine glands, were labelled. In addition, the nuclei of the cells in the luminal epithelium of the prostate and seminal vesicles contained silver grains. The interstitial cells of the seminal vesicles, prostate and ductus deferens, and the smooth muscle of the prostate and ductus deferens, but not the seminal vesicles, demonstrated an uptake of radioactivit

ISSN:1422-6405    

DOI:10.1159/000145696

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Testes of 6 rats were processed routinely for electron microscopy and, as an incidental finding, interstitial (Leydig) cells were found to contain bundles of unusual cylindrical bodies or macrotubules. These cytoplasmic structures were found in testes of only 2 of the 6 rats and varied in number from 2 to 346 per cell profile, usually in parallel array but with an irregular orientation in approximately 5 % of the cells. The macrotubules were up to 11 μm long, showed a diameter of 130 nm with a wall of 18–20 nm and an inside diameter of about 94 nm. The wall appeared to be formed by two membranes 6–7 nm thick showing a unit membrane structure with a central electron-lucent space of 6 nm. In several instances, the wall membranes appeared corrugated, which may account for the apparent formation of the wall by a spiralling small tubule or tubules of 18 nm diameter. Several macrotubules showed continuity between their wall membranes and elements of endoplasmic reticulum and occasionally two adjacent macrotubules showed continuity at their ends in a U-form. Similar if not identical structures have been described previously in four studies of interstitial cells of the rat renal medulla, in one instance correlated with water-deprivation. They have been considered an alteration in the endoplasmic reticulum. Also, they have been reported in pig uterine glands in pregnancy. They may represent a cellular response to an unrecognized physiopathological s

ISSN:1422-6405    

DOI:10.1159/000145697

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The Effect of fighting stress on blood leucocyte count was studied in the adult male bandicoot rat. Exposure to fighting stress for 3 h induced neutrophilia, eosinopenia, lymphopenia and monocytopenia. The changes were more significant in the subordinate rat than in the dominant animal. It is suggested that leucocyte responses to fighting are perhaps mediated by the adrenal gland in these animals.

ISSN:1422-6405    

DOI:10.1159/000145698

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

At the present time, complete agreement on the origin and course of parasympathetic preganglionic fibers to the alimentary canal has not been reached. The purpose of this study was to trace vagal fibers to the abdominal cavity and to follow the distribution of these fibers to the digestive tube. The technique used was to label neurons in the dorsal motor nucleus of the vagus (DMX) with 3H-leucine and then to follow the orthograde transport. 16 albino rats were used in this experiment. The right DMX in one group of rats and the left DMX in the other group was injected with 25 μCi of 3H-leucine in three injections. The injection sites and tissue sections from various areas of the digestive tube were processed for autoradiography. A heavy label was observed in the injection site and it could be traced down the vagus nerve through the thorax into the abdomen. Labelled vagal fibers were found in the parasympathetic ganglia of the stomach, small intestine and colon

ISSN:1422-6405    

DOI:10.1159/000145699

出版商:S. Karger AG    

年代:1983

数据来源: Karger