摘要:

Pancreatic islets from adult Wistar rats were isolated by an improved collage -nase digestion technique. Examination of the preparations showed that they contained B cells possessing secretory granules, each having an eccentric electron-dense core surrounded by an electron-lucent halo; the Golgi bodies with their characteristic features were located in a juxtanuclear position. Roughly surfaced endoplasmic reticulum and mitochondria were present and were mostly normal in appearance. The cell possessed all the ultrastructural attributes indicating that they were fully functional and structurally intact.

ISSN:1422-6405    

DOI:10.1159/000147348

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The distribution of calcitonin gene-related peptide (CGRP)- and substance P (SP)-immunoreactive (IR) nerve fibers and their correlation in the periodontal ligament of mouse incisors were examined by indirect immunofluorescence. Both CGRP-IR and SP-IR thin nerve fibers were abundant in the apical and middle third of the periodontal ligament. In the lingual portion of the incisal periodontal ligament, these nerve fibers were localized in the alveolar half of the periodontal ligament and were observed as free nerve endings. No CGRP-IR and SP-IR specialized nerve endings, such as Ruffini-like corpuscles, were observed. In the labial periodontal ligament, CGRP-IR and SP-IR nerve fibers ran along the incisal axis. The distribution of CGRP-IR nerve fibers was very similar to that of SP-IR nerve fibers.

ISSN:1422-6405    

DOI:10.1159/000147349

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The development of tumorigenic conditions in the carcinogen-exposed rat colon was studied using selected morphological, histochemical, immunohistochemical and biochemical methods of analysis. Rats were treated with two carcinogens: 1,2-dimethylhydrazine and N-methyl-N’-nitro-N-nitrosoguanidine alone or with deoxycholic acid as a tumor promoter. It was found that 3 months after treatment of animals with the carcinogens the following changes were developed in colonic tissue: infiltration of lymphocytes in the mucous membrane, high increase in mitotic index among epithelial cells, negative reactions of colonic cells for neutral mucopolysaccharides and sulfomucins and positive reactions to carboxyl groups, nonsulfated acid mucosubstances and tissue polypeptide antigens. An increase in the activity of ornithine decarboxylase in colonic tissue was developed within the same time period and has been seen only in those tissues which were characterized by the development of precancerous conditions. Individual variations were observed in the manifestation of the studied parameters in rat neoplastic colonic tissues. It is suggested that these differences reflect an individual sensitivity of animals to carcinogens and the magnitude of the dysplastic processes induced in the colo

ISSN:1422-6405    

DOI:10.1159/000147350

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The ultrastructure of the parathyroid glands of fetal and pregnant golden hamsters exposed to 5-gravity environment was studied. In the centrifuged fetal animals the Golgi complexes associated with some prosecretory granules were significantly increased compared with those of the control fetal animals, and several secretory granules were located in a peripheral position just beneath the plasma membrane. In the centrifuged pregnant animals the Golgi complexes associated with numerous prosecretory granules were significantly increased, cisternae of the granular endoplasmic reticulum appeared to be increased compared with those of the control pregnant animals, many secretory granules were located in the peripheral cytoplasm and several granules were situated close to the plasma membrane. These findings suggest that in the parathyroid glands of the fetal golden hamsters as well as the pregnant animals the synthesis and release of parathyroid hormone may be stimulated in response to a hypergravity environment.

ISSN:1422-6405    

DOI:10.1159/000147351

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

In the preferential harvesting of rounded mitotic (M phase) cells of human Chang liver monolayer cultures by mechanical agitation in Ca2+-free phosphate-buffered saline, degranulation of endoplasmic reticulum (ER) was observed. Mitotic cells are known to have a series of Ca2+ transients and, without being subjected to Ca2+-free washings, did not have degranulated ER. Quiescent cells incubated with 0.7 mM adenosine 5’-triphosphate (ATP) in Ca2+-free HEPES-buffered saline produced very similar ER degranulations. Confocal argon laser imaging of fluo-3-loaded cells showed a Ca2+ transient peaking at 2 min after ATP treatment. In the absence of extracellular Ca2+ transients of Ca2+ elevation in the cytosol would exit the cell in a down-gradient, draining the ER Ca2+ stores. Substituting ATP with 1 µM brominated A23187 calcium ionophore in the incubation that contained 1-100 mM CaCl2, respectively, did not produce ER degranulation, thereby excluding raised cytosolic Ca2+ per se as the cause of ER degranulation. In fact, incubation with 0.7 mM ATP in the presence of 1-5 mM CaCl2 failed to produce ER degranulation. ER degranulated cells, from treatment with ATP without extracellular Ca2+ as well as from Ca2+-free washings at M phase, could be rescued by subsequent incubation in growth medium that contains Ca2+ whereupon the rounded cells re-flatten (a round-to-flat change) and have well-defined rough ER. It therefore seems possible for Ca + depletion, or at least a reduction, to be causally related to ER degranulation. If that were the case, ER granularity would appear to be a facultative rather than a constitutive sta

ISSN:1422-6405    

DOI:10.1159/000147352

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The present immunocytochemical study revealed γ-aminobutyric acid (GABA) immunoreactivity in the oxyntic and pyloric mucosa of the rat stomach at light-and electron-microscopic levels. GABA-immunoreactive endocrine cells were numerously seen in the lower half portion of the pyloric mucosa but rarely in the oxyntic mucosa. These cells were round or oval in shape and sometimes had a short cytoplasmic process. Serotonin-immunoreactive enterochromaffin (EC) cells were also observed in the oxyntic and pyloric mucosa of the stomach. The distribution and shapes of the immunoreactive cells were similar to those of the GABA-immunoreactive cells. With a double immunolabeling technique using anti-GABA and antiserotonin serum, GABA-immunoreactive endocrine cells showed serotonin immunoreactivity and were identified as EC cells. At the electron-microscopic level the GABA-immunoreactive cells contained round or oval, spindle-like, pear-shaped granules in EC cells. The immunoreaction product in the EC cells was generally confined to the granular cores. These findings suggest that GAB A may be synthesized in the EC cells and be released from the granules of the cells after adequate stimuli

ISSN:1422-6405    

DOI:10.1159/000147353

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

In this study, an attempt has been made to examine and analyse the ancieni mandibles of people who have died several hundreds of years ago during the second and first millenium B.C. These mandibles have been recovered from the burial mounds in Bahrain (Arabian Gulf) and preserved in the Nationa Museum and the Department of Antiquities in Bahrain. The dental conditions recorded are e.g. attrition, caries, fluorosis, periodontitis or antemortem tooth loss. The results indicate the age, sex, diet, occupation and environmental con ditions that existed and even the culture of the people. A comparative study of the ancient mandibles and those of the present generation has been carried out

ISSN:1422-6405    

DOI:10.1159/000147354

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The present paper describes mucous cells in the forestomach glandular regior which immunoreacted to antibovine pepsinogen serum in adult and young bac trian camels, Camelus bactrianus (female, 25 years old; female, 6 months old from Hilar Inner Mongolia, People’s Republic of China, in August 1988). Thest immunoreactive cells in forestomach glandular regions also reacted to Alciai blue (pH 1.0) and/or periodic acid-Schiff. Cross-reactivity of antibovine pep sinogen serum against extracts from the forestomach glandular region waí analyzed by Western blotting, supporting that this serum could detect pepsir and/or pepsinogen in the bactrian camel. It was suggested that mucous cells ii forestomach glandular regions produce pepsinogen molecul

ISSN:1422-6405    

DOI:10.1159/000147355

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

This paper studies the influence of an antimitotic factor (puromycin) and a hormonal factor (thyroid hormone, TH) on canal growth. The tibiae of 15 six-day-old rats were cultured in a serum-free chemically defined medium. The cultures were carried out for as long as 6 days. Our results show: (1) canal growth is not dependent on perichondrium or chondroepiphysis growth; (2) the canal is greater and has a complex pattern in a triiodothyronine (T3)-treated assay group; (3) round and multinucleated cells are more numerous in the T3-treated assay group than in the other groups. We hypothesize that the canal grows by a physiological phenomenon of programed cell death and that it is stimulated by TH.

ISSN:1422-6405    

DOI:10.1159/000147356

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Glycolipids, glycoproteins, glycosaminoglycans and sialoglycoproteins have all been implicated in a number of developmentally significant processes related to complex interactions between cell surfaces and the extracellular matrix. The present study was designed to localize glycoconjugates recognized by peanut agglutinin (PNA) and Madura pomifera (MPA) lectins during mouse molar root development. Postnatal ICR mice at 10, 15, 21, 28 and 42 days were used. Lower jaws were dissected, fixed in 4% paraformaldehyde, decalcified in 5% EDTA and embedded in paraffin. Serial sections were made and stained with FITC-conjugated PNA or MPA. β-Lactose was used as an inhibitory sugar for PNA, and α-D-melibiose for MPA. PNA specifically stained Hertwig’s epithelial root sheath (HERS), whereas MPA stained a number of tissues. The outermost layer of root dentin, forming cellular cementum, alveolar bone and HERS showed positive reactions with MPA. Glycoconjugates localized by the lectins may be functionally related to molecules which contribute to root formation and cementogene

ISSN:1422-6405    

DOI:10.1159/000147357

出版商:S. Karger AG    

年代:1992

数据来源: Karger