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61.
Giovanni Savettieri Rosa Guarneri Giuseppe Salemi Vincenzo La Bella Donatella Ferraro Salvatore Scondotto Federico Piccoli 《Neurochemical research》1990,15(8):773-776
[3H]Flunitrazepam (FNZ) binding to cortical neurons from fetal rat brain was investigated in vitro. The use of a synthetic medium specific for neurons made it possible to plot a developmental curve of3H-FNZ binding in an almost pure neuronal culture. Detectable specific binding was present in vitro at time 0 (that is, the 16th gestational day). A progressive increase of binding, due to an increment in the number of recognition sites, was observed on the subsequent days. The affinity of the specific binding sites to3H-FNZ was enhanced by the addition of exogenous GABA, whereas the density was not affected. 相似文献
62.
The daily and seasonal distribution of airborne fungal particles was recorded in a high altitude tropical zone. Sampling was
carried out in the southern part of Mexico City. An Andersen air sampler was used over a period of six months. Ten minutes
sampling for each set of plates was done at fixed schedule: 07:30, 14:00 and 19:00 hours. The sampler was placed 10 m above
the ground. Daily variation was found to be associated with the season, weather and atmospheric stability. The highest value
of mold counts (3195 CFU m−3) was recorded in the evening on October, a transitional month between the rainy and the dry seasons, the lowest (45 CFU m−3) at noon during the rainy season. Mold counts were significantly correlated with temperature, having negative signs both
in the morning and at noon, and being positive in the evening. The abundance of only three genera was recorded.Cladosporium, was isolated more frequently, and its abundance at 14:00 h was of 38%;Alternaria represented 4.0%, at 14:00 h, andAspergillus 3.0% at 7:30 h. Fifteen species belonging to the latter genera were identified and most of them are considered as opportunistic
molds of clinical significance. 相似文献
63.
64.
The structure of an HLA-A2.4 functional variant (A2.4c) expressed on donor KLO has been examined by comparative peptide mapping with other HLA-A2 antigens of known structure and radiochemical sequencing. All the peptide differences between A2.4c and A2.1 could be accounted for by five amino acid changes at positions 9, 43, 66, 95, and 156. The nature of residues 9, 43, and 95 in A2.4c was determined by sequencing to be identical to those in A2.2Y. The nature of residue 156 in A2.4c was also assigned as identical to that in A2.2Y on the basis of the identity of the corresponding peptide in its chromatographic comparison with A2.2Y. Position 66 was unique to A2.4c. It was determined to be an Asn residue instead of the Lys present in all other HLA-A2 antigens of known structure. This was the only detected amino acid difference between A2.4c and A2.2Y. The results indicate that, from a structural point of view, A2.4c is most closely related to the A2.2 subtype antigens and not to other A2.4 antigens. The data are compatible with the assumption that A2.4c was derived from A2.2Y by a single point mutation event. 相似文献
65.
Raúl Castaño Angel Ezquerra Nieves Doménech José A. López de Castro 《Immunogenetics》1988,27(5):345-355
The HLA-A2 antigen expressed by donor OZB can be distinguished from the main HLA-A2.1 subtype by isoelectric focusing - it is one charge unit more acidic — and by some alloreactive T-cell clones but not by cytolytic T lymphocyte lines. The structure of variant OZB has been examined by comparative peptide mapping with A2.1 and radiochemical sequence analysis. The two molecules were found to differ in a single tryptic peptide from the 0 region, spanning residues 220–243. The amino acid sequence of this peptide from variant OZB revealed that there was only one amino acid change of Glu instead of Ala at position 236, a hitherto invariant residue in class I HLA antigens. All previously characterized HLA or H-2 natural variants have structural changes restricted to the 1 and/or 2 domains. Thus, variant OZB is unique in that (1) it has one amino acid change in 3 and (2) it has no changes in l and 2. The only detected substitution of this variant may be accounted for by a single base change at the DNA level, suggesting that it might have resulted from a point mutation in the A2.1 gene. The structural features of variant OZB open a novel way to examine the influence of polymorphism in 3 on cytolytic T-cell recognition of naturally occurring class I antigens.Abbreviations CTL
cytolytic T lymphocytes
- HPLC
high performance liquid chromatography
- IEF
isoelectric focusing
- MHC
major histocompatibility complex 相似文献
66.
Chromium is an essential trace element and is associated with some biological pathways, especially with glucose tolerance.
For these reasons, we decided to determine the concentration of chromium in two sets of Brazilian medicinal plants. The first
group consisted of plants that are considered as antidiabetic, whereas the second included plants that do not have this therapeutic
property. The concentration of chromium was determined by flameless atomic absorption. All the plants analyzed contain chromium
in the normal range for this element, but the hypoglycemic plants contain more chromium than the others (1–4 μg/g compared
to 0.5–1.5 μg/g). 相似文献
67.
68.
69.
Giovanni Bernardini Pio Belgiojoso Marina Camatini 《Molecular reproduction and development》1988,21(4):403-408
The motility status of Xenopus laevis spermatozoa does not affect their respiration rate. Oxygen consumption for 109 spermatozoa is approximately 0.4 μmol/minute. Oxygen consumption is not increased by gramicidin D, an uncoupler, and it is not blocked by KCN or NaN3. The adenosine triphosphate (ATP) content of spermatozoa that have been activated is definitely less than that in the spermatozoa that remained immotile. Incubation in KCN, NaN3, and gramicidin decreases the ATP content and impairs motility. The conclusions of the present study are that in Xenopus spermatozoa motility and oxygen consumption are not correlated, and the composition of the respiratory chain of these spermatozoa presents noteworthy peculiarities. 相似文献
70.
Summary A similar pattern of variation with time in observed maxima of daily dose equivalent rates in human thyroids (TD - µSv·d–1) and of daily fallout radioactivities (FR - kBq·m–2) has been found after the Chernobyl accident. An estimate of the time-lag between the maxima in TD lines and the preceding FR peaks was made of about seven days for adult and nine days for juveniles. Applying this time-lag it was possible to estimate transfer factors from the fall-out to thyroid dose equivalent: the highest estimated values were 221 µSv/kBq·m–2 for adult and 641 µSv/kBq·m–2 for juvenile thyroids. These values differ from those published by UNSCEAR (United Nations 1988), which have been calculated for various regions of Czechoslovakia, from ingestion and inhalation intake estimates. A broad variation of transfer factor values could be expected to result from such transfer calculations using ingestion and inhalation estimates. The findings also support the concept of a need for prolonged iodine prophylaxy after emissions of radioiodine into the environment.Abbreviations TD
dose equivalent rates in thyroids [µSv·d–1]
- FR
fall-out radioactivity (-ies) [kBq·m–2] 相似文献