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1.
Staphylococcal enterotoxins A and C1 (SEA or SEC1) bound to major histocompatibility-I (MHCI) molecules with high affinity (binding constants ranging from 1.1 microM to 79 nM). SEA and SEC1 directly bound MHCI molecules that had been captured by monoclonal antibodies specific for H-2Kk, H-2Dk, or both. In addition, MHCI-specific antibodies inhibited the binding of SEC1 to LM929 cells and SEA competitively inhibited SEC1 binding; indicating that the superantigens bound to MHCI on the cell surface. The affinity and number of superantigen binding sites differed depending on whether MHCI was expressed in the membrane of LM929 cells or whether it was captured. These data support the hypothesis that MHCI molecules can serve as superantigen receptors.  相似文献   

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Where lymphatic filariasis has diminished since about the 1950s, it has most frequently, though not always, been a direct result of chemotherapeutic intervention against the parasite. Diethylcarbamazine (DEC), a well-established drug, has been the single agent of chemotherapeutic control and has been successful in a wide variety of regimens. This paper reviews the experience with one strategy: long-term, low-dose treatment through DEC-medicated common salt. Diethylcarbamazine-medicated salt played a major role in the Chinese filariasis control program and has been successful in more limited trials in India, Brazil, and Tanzania. It is not being used today in any endemic area, but the evidence suggests that it is safe, effective, and relatively inexpensive. Enough is already known about the beneficial effects of DEC-medicated salt from community-wide studies to develop specific guidelines for its use in community programs.  相似文献   

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Two girls aged 11 months and 6 years, presented with an invasive group A streptococcal (GAS) infection during the course of primary varicella. The infant had severe cellulitis of the left arm and leg, fever and bacteraemia. She developed osteomyelitis of ulna and tibia. The 6-year-old girl had a fever > 38.5 degrees C, hypotension, an acute respiratory distress syndrome, liver function abnormalities, and positive cultures of blood and joints. Her clinical picture was compatible with a GAS-associated toxic shock syndrome. If during the course of primary varicella persistent fever, secondary fever or pain in one or more extremities occurs, invasive bacterial infection by GAS or Staphylococcus aureus should be considered, even in the absence of skin infection or cellulitis.  相似文献   

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OBJECT: The aim of this study was to determine the usefulness of magnetic resonance (MR) imaging-documented extravasation as an indicator of continued hemorrhage in patients with acute hypertensive intracerebral hemorrhage (ICH). METHODS: The authors studied 108 patients with acute hyperintensive ICH. Imaging modalities included noncontrast-enhanced computerized tomography (CT) scanning, gadolinium-enhanced MR imaging, and conventional cerebral angiography obtained within 6 hours after the onset of hemorrhage. A repeated CT scan was obtained within 48 hours to evaluate enlargement of the hematoma. Findings on MR imaging indicating extravasation, including any high-intensity signals on T1-weighted postcontrast images, were observed in 39 patients, and 17 of these also showed evidence of extravasation on cerebral angiography. The presence of extravasation on MR imaging was closely correlated with evidence of hematoma enlargement on follow-up CT scans (p < 0.001). CONCLUSIONS: Evidence of extravasation documented on MR imaging indicates persistent hemorrhage and correlates with enlargement of the hematoma.  相似文献   

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BACKGROUND: Nitric oxide (NO) seems to play an important role in modulating tissue injury during reperfusion of the liver. In this study, we have evaluated and compared the effects of FK409 (FK), a potent spontaneous NO releaser, and L-arginine in ischemia-reperfusion injury of the rat liver. METHODS: Male Sprague-Dawley rats underwent 90 min of hepatic ischemia followed by reperfusion. FK or L-arginine was used (intravenously) in two different doses for each drug (group I, 3.2 mg/kg FK; group II, 1.6 mg/kg FK; group IV, 100 mg/kg L-arginine; and group V, 300 mg/kg L-arginine). Saline was used in control animals (group III). Hepatic enzyme status, microcirculation, serum nitrite (NO2-) and nitrate (NO3-) and tissue injury score were evaluated at predetermined times. RESULTS: Serum NO2-/NO3- was elevated immediately by FK treatment dose-dependently but not by L-arginine. However, L-arginine caused late (6-24 hr) elevation of the NO metabolites dose-dependently. The elevation of serum aspartate aminotransferase and alanine aminotransferase was suppressed and hepatic microcirculation was improved in the FK-treated groups dose-dependently. L-Arginine also improved the microcirculation, but hepatic enzymes at 24 hr of reperfusion were significantly higher in group V than in the control group. These findings were well reflected by the extent of tissue injury in respective groups. CONCLUSION: FK treatment in the immediate reperfusion period improves hepatic microcirculation and confers a significant protective effect on hepatic ischemia-reperfusion injury in the rat.  相似文献   

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In an area in which brugian filariasis is endemic, when cytokine levels were analyzed as a function of clinical status comparing those who were asymptomatic and amicrofilaremic with those who were microfilaremic, it was found that both interferon (IFN)-gamma and interleukin (IL)-5 were suppressed in microfilariae carriers (P < .01 and P < .001, respectively), but IL-4 was unabated. Age had a significant effect on cytokine production in both groups. In asymptomatic amicrofilaremic subjects, IL-4 production was high in young persons and decreased with age, whereas in microfilaremic subjects, IL-4 increased significantly with age. Conversely, IFN-gamma showed a tendency to increase with age in asymptomatic amicrofilaremic subjects but not in microfilaremic subjects. IL-5 decreased significantly with increasing age in both asymptomatic amicrofilaremic and microfilaremic groups. These results indicate that the length of exposure to and infection with filarial parasites can each exert a substantial effect on the cytokine response profiles of host T cell populations.  相似文献   

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Heritability is well known to be a poor indicator of genetical variation in fitness. We show here that it is also an inadequate measure of genetical variation in fecundity.  相似文献   

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Monitored the skin-potential responses of 6 college students while each was seen for 10 counseling sessions. Results indicate that the nature of a S's skin-potential wave was generally a reliable indicator of the way the S was managing or experiencing his feelings, as reported on the Mood Adjective Check List during the sessions. Negative skin-potential responses were accompanied by feelings described as pleasant and released; positive responses were associated with unpleasant and inhibited feelings, and neutral responses were often associated with unpleasant and inhibited feelings but also tended to coincide with thoughtful moods. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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Many studies on perceptual development in infancy use visual attention behaviour as an indicator of intellectual capacities. Decrement of attention with repeated exposure to a visual stimulus (habituation) and recovery of attention to a novel stimulus (dishabituation) are interpreted as reflecting the infant's processing of stimulus information. This information processing interpretation as well as the main empirical habituation-dishabituation procedures are explained. Furthermore, sensory adaptation arguments for habituation and dishabituation are discussed and refuted. Following this critical discussion, empirical evidence for the information processing point of view is given. In this context, investigations are mentioned which indicate substantial correlations between early habituation and dishabituation and later intelligence. These studies support a continuity perspective of mental development from infancy.  相似文献   

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B Greatrex 《Canadian Metallurgical Quarterly》1997,6(9):486, 488, 490-486, 488, 493
The incidence of beta-haemolytic group B streptococcal infection in babies at or shortly after birth appears to have risen during the last 20 years. About 30% of women could be colonized at any one time, and because of the transient nature of this organism research has failed to find a way of identifying women who will be colonized at the end of pregnancy. The baby is at risk of early-onset disease from mother-to-baby transmission during the birth process. If identified early enough, those mothers who present a risk can be treated in time to protect the baby during the birth. Late-onset disease can be the result of cross-infection from carers, and the education of midwives, nurses and mothers could reduce the risk. Education could also aid identification of the early signs of disease, and therefore increase the likelihood of a successful outcome of treatment.  相似文献   

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OBJECTIVE: The relationship between exposure to naphthalene and urinary excretion of naphthols was examined. METHODS: Concentrations of naphthalene and naphthols in breathing-zone air during a workshift and 1-naphthol and 2-naphthol in urine collected after the workshift were determined for 102 male workers. Gas chromatography with a flame ionization detector (GC-FID) was used to determine the air concentration. Urine naphthols were extracted after acid hydrolysis by solid-phase extraction and separated by the GC-FID method. Naphthalene homologues in air and their metabolites in urine samples were identified by gas chromatography-mass spectrometry. RESULTS: 1-Naphthol, 2-naphthol and 1,4-naphthoquinone were identified in the urine samples. The time-weighted average concentrations of naphthalene and naphthols in the breathing-zone air showed that the exposure level of the workers was rather low. The geometric mean values were as follows: 0.77 and 0.87 mg/m3 for naphthalene, 0.016 and 0.034 mg/m3 for 1-naphthol, 0.012 and 0.067 mg/m3 for 2-naphthol during tar distillation and naphthalene oil distillation, respectively. The corresponding urinary concentrations of 1- and 2-naphthols were 693.1 and 264.4 micromol/mol and 264.4 and 297.7 micromol/mol creatinine, respectively. The correlation coefficients between the naphthol concentrations in urine and the breathing-zone air concentrations of naphthalene were statistically significant, varying in the range of 0.64--0.75 for 1-naphthol and 0.70--0.82 for 2-naphthol. There was linear dependence (r = 0.76) between the summary concentration of naphthols in urine and the naphthalene concentration in air. CONCLUSIONS: Workers in tar distillation and naphthalene distillation are exposed to rather low concentrations of naphthalene and methylated naphthalenes and naphthols. Naphthols and 1,4-naphthoquinone identified in the urine appear to be the products of the hydroxylation of naphthalene present in the breathing-zone air. These findings suggest that the summary concentration of naphthols in urine can be used as a biomarker for naphthalene exposure.  相似文献   

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The purpose of this investigation was to examine the relationship between the root surface structure of human teeth and the age of the individual and also to evaluate whatever contribution this relationship might give to multiple regression methods for age estimation. The material, consisting of 1000 permanent teeth, excluding molars, was examined by means of a new scoring system (Surface Roughness Scores, SRS) for surface roughness, in addition to the scoring systems of Gustafson (RG) and Johanson (RJ) for root resorption. Statistical analyses using the SPSS package indicated a symmetric left/right distribution of root surface structure. The Pearson correlation between age and RJ varied from -0.02 for maxillary central incisors to 0.54 for mandibular central incisors and was approximately the same for RG. These two scoring systems seem to be of little value in methods for age estimation. Correlations between age and the new scoring systems SRS were significant for all teeth and varied from 0.44 for maxillary second premolars to 0.68 for mandibular first premolars. There was no detectable influence of gender or reason for extraction. However, the SRS could not be assessed with sufficient reproducibility, and the estimates were therefore too subjective to be used as the sole criterion for age estimation. This scoring system could, however contribute positively to a multiple regression method.  相似文献   

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