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11.
Ohne Zusammenfassung 相似文献
12.
Dopamine content and metabolism in mesencephalic and diencephalic cell cultures: sex differences and effects of sex steroids. 总被引:7,自引:0,他引:7
Sexual differentiation of dopaminergic neurons was studied in gender-specific cultures. Dissociated cell cultures were prepared from di- or mesencephalon of gestational day 14 rat embryos and raised in the absence or presence of 17 beta-estradiol or testosterone for up to 13 days in vitro (DIV). Developmental profiles of levels of dopamine (DA) and metabolites as well as capacity for vesicular storage of the transmitter were determined by HPLC. Tyrosine hydroxylase-immunoreactive (TH-IR) neurons were counted. Higher levels of DA were measured in female than in male cultures of both brain regions. In mesencephalic cultures, the differences in DA levels were fully accounted for by sex differences in numbers of TH-IR cells, whereas no sex differences in cell numbers were found in diencephalic cultures. Dihydroxyphenylacetic acid (DOPAC) levels and vesicular storage capacity matured faster in mesencephalic than in diencephalic cultures, but no sex differences were observed. Homovanillic acid (HVA) could not be detected except in 13-DIV mesencephalic cultures. Hormonal treatment did not erase sexual differentiation of dopaminergic neurons. Irrespective of the gender, however, both steroids decreased DA and DOPAC contents in diencephalic cultures but not in mesencephalic cultures. It is proposed that sexual differentiation of dopaminergic systems proceeds in a region-specific fashion and that neurogenesis and development of various parameters of dopaminergic activity may be differentially affected. Sexual differentiation of dopaminergic neurons may be initiated independently of the action of gonadal steroid hormones and may subsequently be modified by differences in hormonal environment. 相似文献
13.
Multiple connexins confer distinct regulatory and conductance properties of gap junctions in developing heart. 总被引:4,自引:0,他引:4
Multiple gap junction proteins (connexins) and channels have been identified in developing and adult heart. Functional expression of the three connexins found in chick heart (connexin42, connexin43, and connexin45) by stable transfection of communication-deficient neuro2A (N2A) cells revealed that all three connexin cDNAs are capable of forming physiologically distinct gap junctions that differ in their transjunctional voltage dependence and unitary channel conductances. The transjunctional voltage dependences of connexin45 and connexin42 closely resembled those of 4-day and 18-day embryonic chick heart gap junctions, respectively. The multiple channel conductances between 80 and 240 pS, including the predominant 160 pS channel, observed in embryonic chick heart were also common to connexin42. The expression of multiple gap junction channels with distinct conductance and regulatory properties within a given tissue may account for developmental changes in intercellular communication. 相似文献
14.
Lead poisoning in six captive avian species 总被引:2,自引:0,他引:2
W. Nelson Beyer James W. Spann Louis Sileo J. Christian Franson 《Archives of environmental contamination and toxicology》1988,17(1):121-130
Red-winged blackbirds (Agelaius phoeniceus), brown-headed cowbirds (Molothrus ater), common grackles (Quiscalus quiscula), mallards (Anas platyrhynchos), northern bobwhites (Colinus virginianus), and eastern screech-owls (Otus asio) were poisoned with a concentration of lead (Pb) acetate in the diet which was increased by 60% each week until half of the birds in each treatment group died; surviving birds and all control birds except screech-owis were then killed by euthanasia. An additional group of mallards was poisoned with Pb shot. The gizzards of mallards poisoned either way usually were stained with bile; some of these birds also had proventricular impaction. Most poisoned birds of the other species were emaciated but lacked other gross lesions caused by Pb poisoning. In birds other than mallards, Pb poisoning could not be diagnosed without histological or hematological examinations or analysis of tissues. Poisoned birds of all six species could be reliably separated from control birds by an increase in the protoporphyrin concentrations in the blood and by a decrease in the activity of delta-aminolevulinic acid dehydratase (ALAD) in red blood cells. Hepatic iron (Fe) concentrations varied so much among individual birds that even though median hepatic Fe concentrations increased in poisoned birds, hepatic Fe concentrations were not useful in identifying poisoned birds. Renal intranuclear inclusion bodies occurred in 83% of all birds dying from Pb poisoning. Nephrosis, myocardial necrosis, and arterial fibrinoid necrosis were occasionally present. Median hepatic Pb concentrations varied from 20 ppm (wet wt) in male red-winged blackbirds to 111 ppm in female northern bobwhites. Median renal Pb concentrations varied from 22 ppm in redwinged blackbirds to 190 ppm in female northern bobwhites. Hepatic and renal Pb concentrations varied substantially among birds within each species. Median hepatic and renal Pb concentrations of birds that died were not statistically different (p > 0.05) from those of birds that were killed. Lead shot and Pb acetate affected mallards similarly. 相似文献
15.
Venöse Thromboembolien (VTE) stellen eine häufige Morbiditäts- und Mortalitätsursache dar; die jährliche Inzidenz wird mit etwa 1 : 1 000 angegeben. Dabei sind verschiedene Risikogruppen zu unterscheiden, die sowohl durch endogene Faktoren (z. B. genetisch deteminierte Thrombophilie), viel häufiger aber durch exogene Faktoren (zugrundeliegende Erkankung) charakterisiert werden. Diese Heterogenität resultiert in Besonderheiten bei Prophylaxe und Therapie von VTE, auf die in dieser Darstellung eingegangen werden soll. 相似文献
16.
S. W. Han R. Flamm C. Y. Hachem H. Y. Kim J. E. Clarridge D. G. Evans J. Beyer J. Drnec D. Y. Graham 《European journal of clinical microbiology & infectious diseases》1995,14(4):349-352
Various transport and storage conditions for the recovery ofHelicobacter pylori from gastric biopsies were evaluated. Gastric mucosal biopsies from 16Helicobacter pylori-infected patients were stored in cysteine-Albimi medium containing 20 % glycerol in a refrigerator (4°C) for 1 and 2 weeks and in a –20°C laboratory freezer for 4 and 12 weeks. Two clinical isolates were stored in saline, Stuart's transport media, cysteine-Albimi broth with 20 % glycerol, brucella broth with 20 % glycerol and skim milk with 17 % glycerol at room temperature, 4°C, –20°C and –70°C. Storage at 4°C for 1 and 2 weeks resulted inHelicobacter pylori recovery from 81 % and 19 % of biopsies, respectively. Storage at –20°C yieldedHelicobacter pylori recovery in 100 % and 57 % after 4 and 12 weeks, respectively. At room temperature after 6 h, theHelicobacter pylori titer was reduced. The best storage media for frozen isolates were skim milk/glycerol, brucella broth/glycerol and cysteine-Albimi/glycerol (in descending order). Recovery was better at –70°C than –20°C. 相似文献
17.
R. R. Cocco K.-M. Järvinen N. Han K. Beyer H. A. Sampson 《Clinical and experimental allergy》2007,37(6):831-838
BACKGROUND: For immunotherapeutic approaches, 'critical' amino acids (AAs) within allergenic epitopes are replaced with alternate AAs to eliminate IgE antibody binding. OBJECTIVE: To determine the critical AAs for IgE binding in beta-casein and beta-lactoglobulin (BLG). METHODS: Peptides of 10-14 AAs in length were synthesized on a derivatized cellulose membrane with single AA substitutions (alanine or glycine) at each position. Membranes were incubated with a pool of sera from 15 cow's milk-allergic patients and individual sera from six of the 15 patients. In cases where no decrease in binding occurred with a single AA substitution, peptides with two AA substitutions were generated and labelled. RESULTS: Using pooled patient sera, single AA substitutions led to complete elimination of binding to six of 11 peptides for beta-casein and to all six peptides for BLG. Substituting two AAs led to an elimination of binding to four of the remaining five beta-casein epitopes. However, in three of the 11 modified beta-casein peptides and five of the six BLG peptides, no decrease in IgE binding occurred in at least one individual patient. For these patients, critical AAs other than those defined by the patient serum pool were identified, indicating a heterogeneous pattern of IgE recognition. CONCLUSION: These results indicate that AAs critical for IgE binding are more heterogeneous than initially defined by pooled milk-allergic patient sera. For future immunotherapeutic interventions with mutated peptides, critical AAs should also be identified with individual patient sera to account for heterogeneity of IgE binding between patients. 相似文献
18.
F Schneider H Ellgring J Friedrich I Fus T Beyer H Heimann W Himer 《Pharmacopsychiatry》1992,25(5):233-239
This paper describes the influence of neuroleptic therapy on facial action in drug-naive schizophrenics. In a comparative study of medicated and unmedicated schizophrenic patients, the coordinates of 12 small light-reflecting points, attached to subjects' faces, were computer-recorded and analyzed automatically during a semi-standardized clinical interview. In addition, facial activity in videotaped interviews was coded using the Facial Action Coding System (FACS). Each sample group comprised of eight patients with the DSM-III-R diagnostic criteria "schizophrenia" or "schizophreniform disorder". Subjects were studied on two occasions, one shortly after admission to the hospital, the other three weeks later. Group 1 was unmedicated during the first session, whereas group 2 was medicated throughout the study. Three weeks after the start of medication, at the second interview, both recording methods showed a reduction in facial activity and facial expression across all subjects in group 1. The facial action of patients in group 2, however, remained unchanged. 相似文献
19.
Lafont BA Rivière Y Gloeckler L Beyer C Hurtrel B Paule Kieny M Kirn A Aubertin AM 《Virology》2000,266(2):286-298
We have analyzed the nef gene sequences amplified from 12 macaques presenting various patterns of infection with SIVmacBK28-41, a clone derived from attenuated SIVmacBK28. We have observed seven mutation hot spots at positions 56, 75, 432, 588, 680, 699, and 779. The major alteration was a thymidine insertion at position 699, leading to a frameshift in the SIVmacBK28-41 nef gene and changing the last 15 amino acids of Nef into a 31-amino-acid-long C-terminal domain nearly identical to that encoded by pathogenic SIVmac239 and SIVmac251. The insertion was found at early time points in proviruses obtained from rapid progressor macaques, after 2 years postinfection in progressors, and rarely or only after 4 years postinfection in nonprogressors. Fixation of the other mutations occurred only after insertion of thymidine 699. Phylogenetic analysis demonstrated that the nef genes isolated from progressors evolved from the allele present in SIVmacBK28-41 to alleles present in SIVmac239 or SIVmac251, whereas nef sequences from nonprogressors stayed clustered with that of the inoculated molecular clone. These data stress the importance of the C-terminal extremity of the Nef protein of SIVmac239 or SIVmac251 in viral pathogenesis. 相似文献
20.