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61.
62.
Parathyroid hormone receptors in human dermal fibroblasts: structural and functional characterization 总被引:3,自引:0,他引:3
Previous studies have established the presence of parathyroid hormone (PTH)-sensitive adenylate cyclase activity in cultured human skin fibroblasts. The present study was undertaken to identify and quantitate PTH receptors directly in such cells. Human dermal fibroblast cell line CRL 1564 was found to possess specific binding sites for [125I]PTH(1-34). These sites bound PTH selectively; bovine and human PTH(1-34) and PTH(1-84) competed for [125I]PTH(1-34) binding sites, whereas the unrelated peptides calcitonin, insulin, AVP, angiotensin II, and ACTH(1-24) were inactive even at micromolar concentrations. Competitive binding experiments demonstrated the presence of binding site heterogeneity. These data fit a "two-site" model (p less than 0.001) in which one binding component has high affinity (Kd = 2.5 ng/ml = 0.6 nM) and low capacity (10(4) sites/cell) while the other has low affinity (Kd = 5.9 micrograms/ml = 1.5 microM) and high capacity (greater than 10(7) sites/cell). Similar high- and low-affinity [125I]bPTH(1-34) binding sites were seen also in CRL 1564 membranes containing a PTH-responsive adenylate cyclase. The Kd of the high-affinity sites was identical to the concentration of unlabeled bPTH(1-34) (4.2 ng/ml = 1.0 nM) required to half-maximally elevated cyclic AMP in CRL 1564 cells. Affinity labeling of specific PTH binding sites revealed the presence of multiple components with Mrs of 85, 70, 40, 33, and 23 kD on SDS-PAGE. Competition experiments did not disclose structurally discrete high- and low-affinity sites. Thus, structurally homologous PTH receptors in human skin fibroblasts apparently can assume two affinity states: (i) a high-affinity state coupled to adenylate cyclase and (ii) a low-affinity state that may represent uncoupled receptors. 相似文献
63.
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65.
M. Hřebíček K. Hodaňová J. Ledvinová J. Sokolová M. Elleder J. Zeman L. Vepřeková J. Musilová J. M. F. G. Aerts G. H. Renkema D. Hřebíček 《Virchows Archiv : an international journal of pathology》1996,428(4-5):305-309
We present a case of Merkel cell carcinoma of the thigh diagnosed by conventional histology, immunohistochemistry, electron microscopy and cytogenetics. A unique chromosome 6 trisomy characterized this primary neoplasm, as confirmed by FISH study. The role of chromosome analysis and interphase cytogenetics is emphasized as an adjunct in the subtyping of tumours and their prognostic evaluation. 相似文献
66.
Summary. Two vaccinia virus (VV) strains, WR and Praha, were selected for a study undertaken to determine whether the virus-encoded
interferon-γ receptor (IFN-γR) plays any role in virus virulence. Both of the viruses expressed the B8R gene coding for IFN-γR
in infected cell cultures. The nucleotide sequence of the Praha virus B8R gene was determined, and, when compared with the
published sequence of the WR virus, it only displayed one silent nucleotide substitution. Mutants of the WR and Praha viruses
with deleted B8R gene were constructed. In rabbits, skin lesions produced by the WR B8R-deleted mutants were smaller and tended
to disappear earlier than those caused by wild-type WR virus. Similar results were obtained with both independently prepared
WR B8R-deleted mutants. These data strongly suggested that the product of B8R gene did play a role in virus virulence. A similar
comparison of the wild-type Praha virus and its mutant could not be done because of the very low virulence of the parental
virus for rabbits.
Received March 13, 2000 Accepted August 16, 2000 相似文献
67.
Pericić D Bujas M Mirković K Jazvinsćak M 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1999,129(3):451-456
The effects of adrenalectomy, gonadectomy and combined adrenalectomy plus gonadectomy on the previously described sex-dependent
anticonvulsive effect of swim stress were studied in rats. The convulsive signs (myoclonic twitch, generalized convulsions,
tonic hindlimb extension) were produced by constant i.v. infusion of γ-aminobutyric acidA (GABAA) antagonist bicuculline, which started 15 min after termination of swim stress (10-min swim at 18–19°C). Adrenalectomy decreased
the threshold doses of bicuculline producing the first myoclonic twitch and the onset of generalized convulsions only in females.
In adrenalectomized females, but not in males, swim stress enhanced the threshold dose of bicuculline producing generalized
convulsions, but, unlike in adrenal-intact animals, it failed to enhance the dose of bicuculline producing tonic hindlimb
extension. In gonadectomized stressed and unstressed animals all sex differences disappeared, and swim stress enhanced in
both sexes only the threshold doses of bicuculline producing tonic hindlimb extension. Adrenalectomized plus gonadectomized
animals displayed clear sex differences in doses of bicuculline necessary to produce all the convulsive signs. In the same
animals swim stress postponed, especially in females, the onset of the first myoclonic twitch and generalized convulsions,
but not the onset of tonic hindlimb extension. In summary, our results suggest that hormones of the adrenal and gonadal glands
are only partly responsible for decreased susceptibility, especially of female rats, to the GABAA antagonist bicuculline. Moreover, they have demonstrated that stress produces a gender-specific anticonvulsive effect even
in the animals completely deprived of steroid hormones of peripheral origin.
Received: 4 June 1998 / Accepted: 11 June 1999 相似文献
68.
69.
S. Momčilović C. Cantacessi V. Arsić-Arsenijević D. Otranto S. Tasić-Otašević 《Clinical microbiology and infection》2019,25(3):290-309
Background
Parasitic diseases are one of the world's most devastating and prevalent infections, causing millions of morbidities and mortalities annually. In the past, many of these infections have been linked predominantly to tropical or subtropical areas. Nowadays, however, climatic and vector ecology changes, a significant increase in international travel, armed conflicts, and migration of humans and animals have influenced the transmission of some parasitic diseases from ‘book pages’ to reality in developed countries. It has also been noted that many patients who have never travelled to endemic areas suffer from blood-borne infections caused by protozoa. In the light of existing knowledge, this new trend can be explained by the fact that in the process of migration a large number of asymptomatic carriers become a part of the blood bank donor and transplant donor populations. Accurate and rapid diagnosis represents the crucial weapon in the fight against parasitic infections.Aims
To review old and new approaches for rapid diagnosis of parasitic infections.Sources
Data for this review were obtained through searches of PubMed using combinations of the following terms: parasitological diagnostics, microscopy, lateral flow assays, immunochromatographic assays, multiplex-PCR, and transplantation.Content
In this review, we provide a brief account of the advantages and limitations of rapid methods for diagnosis of parasitic diseases and focus our attention on current and future research in this area. The approximate costs associated with the use of different techniques and their applicability in endemic and non-endemic areas are also discussed.Implications
Microscopy remains the cornerstone of parasitological diagnostics, especially in the field and low-resource settings, and provides epidemiological assessment of parasite burden. However, increased use and availability of point-of-care tests and molecular assays in modern era allow more rapid and accurate diagnoses and increased sensitivity in the identification of parasitic infections. 相似文献70.
Highly purified and concentrated interferons obtained from L cells or from mouse peritoneal leukocytes (MPL) after induction with3H-uridin labeled double-stranded RNA of f2 phageE. coli (phage ds-RNA) were analysed by poly-acrylamide gel electrophoresis. A coincidence of the discrete radioactivity peak with one of the interferon activity peaks was demonstrated. 相似文献