交沙霉素在中国汉族、维吾尔族及哈萨克族中的药代动力学比较

交沙霉素在中国汉族、维吾尔族及哈萨克族中的药代动力学比较李国昌陈春雁杨明义（新疆石河子医学院第一附属医院药剂科，石河子８３２００８；石河子农学院医院，石河子８３２００３）为探讨交沙霉素（ｊｏｓａｍｙｃｉｎ）在不同民族正常人体内过程，我们用相同的受...     

Women worried about their familial breast cancer risk--a study on genetic advice in general practice

AIMS: To ascertain whether women who consulted their GP because they perceived themselves as at increased risk of familial breast cancer were indeed at increased risk, and to evaluate potential strategies for assessing genetic risk of breast cancer in general practice. METHODS: Sixty-seven out of 81 women who had consulted their GP for advice about their possible increased risk of developing breast cancer due to breast cancer in the family were interviewed. Familial breast cancer risk was assessed by a clinical geneticist. This assessment was compared with two recent guidelines for referral for genetic counselling. RESULTS: More than half (52%; n = 35) the women had a relative risk of two and over for developing breast cancer, while another half of these 35 (25%; n = 17) had a relative risk of three and over. All the women (n = 17) with a relative risk of three and over were identified by means of the two current guidelines for referral for genetic counselling, while more than half of the women (61%; n = 11) with a relative risk between two and three were identified. CONCLUSIONS: More than half the women concerned about their familial risk of breast cancer are indeed at increased risk of breast cancer. Current guidelines correctly identify women at high risk. However, doubts about the health gain and feasibility of referral warrant caution, and need further investigation.      

Similarities among hypervariable segments of immunoglobulin chains.

A human lambdaV (Mcg) and a human lambdaII (Vil) myeloma protein have identical sequences in their first hypervariable segments although they differ at 21 positions throughout the variable region. If a different structural gene is responsible for each subgroup, the findings favor insertion of information for the hypervariable or complementarity-determining segments.     

Reaction of germinal centers in the T-cell-independent response to the bacterial polysaccharide alpha(1-->6)dextran.

Primary immunization of BALB/c mice with alpha(1-->6)dextran (DEX), a native bacterial polysaccharide, induces an unexpected pattern of splenic B-cell responses. After a peak of antibody-secreting B-cell response at day 4, deposition of dextran-anti-dextran immune complexes, as revealed by staining with both dextran and antibodies to dextran, occurs and persists in splenic follicles until at least the fourth week after immunization. Antigen-specific B cells appear and proliferate in such follicles, leading by day 11 to development of DEX-specific germinal centers as characterized by the presence of distinct regions of DEX+ peanut agglutinin-positive (PNA+) cells. At this time, fluorescence-activated cell sorter analysis also reveals the appearance of a distinct population of DEX+ PNA+ splenic B cells. In contrast, DEX+ PNA- cells, characterized by intense cytoplasmic staining, are present outside of splenic follicles, peak at day 4 to day 5, and persist until at least day 28. The frequency of these cells correlates with DEX-specific antibody-secreting cells, as detected by the ELISA-spot assay. Thus, in addition to the expected plasma cellular response, the typical T-cell-independent type II antigen, DEX, surprisingly also elicits the formation of antigen-specific germinal centers. These observations raise fundamental questions about the roles of germinal centers in T-cell-independent immune responses.     

Indicators of nutritional status among clients from a New York City methadone treatment center

As the AIDS epidemic in the United States moves steadily into the IV drug-abusing population, knowledge of factors related to immune suppression and disease progression gain in public health importance. Indicators of nutritional status, consisting of anthropometric and hematologic data as well as demographic data, were obtained from a random sample of 130 clients in a New York City methadone treatment center. Subjects for this study were selected according to the entry criteria established for inclusion in a large-scale study of the role of nutritional factors and cell-mediated immunity in a group at high risk of HIV seropositivity. Our results indicate a larger than U.S. population-average heterogeneity for Body Mass Index, hematocrit, and hemoglobin concentration, parameters which are conventionally thought to be proxies for general nutritional status. The findings indicate that while some methadone treatment clients are at low nutritional risk, others are probably at very high risk of adverse drug-nutrient and drug-body habitus interactions as well as being at high risk of acquiring infections commonly associated with HIV-related immunodeficiency.     

Cell surface receptors for ecotropic murine retroviruses: mobile membrane proteins that mediate binding and slow endocytosis of the viral envelope glycoprotein

The gp70 envelope glycoproteins of ecotropic murine leukemia viruses bind to receptors that occur only on mouse and rat cells and on interspecies hybrid cells that contain mouse chromosome 5. A substantial fraction of the gp70 that was bound specifically by these criteria remained undegraded and accessible to extracellular labeling reagents for many hours. Accordingly, cells with ecotropic receptors could be labeled specifically. As seen by immunofluorescence microscopy, the gp70-receptor complexes were uniformly dispersed on mouse fibroblast plasma membranes. These complexes were mobile, and they aggregated into patches when crosslinked by antibodies at 37 degrees, but not when membrane lipid fluidity was frozen at 0 degrees. Ecotropic receptors still bound gp70 specifically after cells were fixed with 3.7% formaldehyde, but these receptors could not be patched, indicating that they were nondiffusible. Viable cells slowly endocytosed gp70-receptor complexes at 37 degrees (approximate half-life 5-7 hr) and the gp70 was then proteolytically degraded in lysosomes. In the presence of 20 microM chloroquine, a lysosomal inhibitor, undegraded gp70 was seen to slowly accumulate in these intracellular organelles. These results suggest that ecotropic receptors mediate a slow internalization of attached ligand. Long-lived binding of gp70 onto surfaces of uninfected cells may explain important features of viral-induced leukemia, the host immune response, and immunosuppression.     

Spinning top urethra: not a normal variant

Spinning top urethra (STU) is a term used to describe a widened posterior urethra seen mainly in girls. It is commonly regarded as a normal variant. The authors studied 30 girls with STU using videourodynamics. Twenty-eight showed bladder instability; 21, a congenital wide bladder neck anomaly; and 20, both instability and a wide bladder neck. One patient had a sensitive bladder. All patients had a urodynamic abnormality. The authors believe that the STU is nearly always an indication of bladder instability or wide bladder neck anomaly. The most common mechanism for the dilatation of the posterior urethra is that unstable contractions are resisted by a voluntary increase in distal sphincter tension so as to prevent leakage of urine. The resulting pressure rise produces distention of the posterior urethra, which will be maximal in subjects with a weak bladder neck mechanism as in the congenital wide bladder neck anomaly. The authors believe that STU is seldom if ever a normal variant.     

Vibrio vulnificus (Lactose-Positive Vibrio) and Vibrio parahaemolyticus Differ in Their Susceptibilities to Human Serum

Eleven Vibrio vulnificus (lactose-positive vibrio) strains were less susceptible to the bactericidal activity of normal human serum or serum treated with magnesium-ethyleneglycol-bis (β-aminoethyl ether)-N,N′-tetraacetic acid than were six Vibrio parahaemolyticus strains.