Highly purified human immunodeficiency virus type 1 reveals a virtual absence of Vif in virions

The vif gene of human immunodeficiency virus type 1 (HIV-1) is essential for the productive infection of primary blood-derived lymphocytes, macrophages, and certain human T-cell lines. It has been shown that Vif is associated with HIV-1 virions purified by sucrose density-equilibrium gradient analysis. However, the specificity of Vif incorporation into virions has not been determined. Moreover, recent studies have demonstrated that standard HIV-1 particle preparations created with sucrose density-equilibrium gradients are contaminated with cell-derived microvesicles. Here we demonstrate, as previously reported, that Vif cosediments with HIV-1 particles in sucrose density-equilibrium gradient analysis. However, we also found that, when Vif was expressed in the absence of all other HIV-1-encoded gene products and then isolated by sucrose density-equilibrium gradient centrifugation from extracellular supernatants, its sedimentation pattern was largely unaltered, suggesting that Vif can be secreted from cells. Using a newly developed OptiPrep velocity gradient method, we were able to physically separate most of the extracellular Vif from the HIV-1 virions without disrupting the infectivity of the virus. By titrating serial dilutions of purified Vif and Gag against the viral peak fraction in the OptiPrep gradient, we demonstrate that <1.0 Vif molecule per virion was present. This study shows that Vif is not significantly present in HIV-1 virions, a finding which is consistent with the idea that Vif functions predominantly in the virus-producing cells during virus assembly. The OptiPrep velocity gradient technique described here could be an easy and rapid way to purify HIV and other enveloped viruses from microvesicles and/or cell debris.     

Does affective blunting in schizophrenia reflect affective deficit or neuromotor dysfunction?

Schizophrenia inpatients withdrawn from all neuroleptic medication were administered measures of affective blunting, diminished affective experience, and neuromotor dysfunction. The correlations among the measures provided support for the hypothesis that measures of affective blunting reflect both neuromotor and affective deficits. Because the interpretation of such measures is therefore ambiguous, measures of diminished affective experience may have greater validity in research on affective deficits in schizophrenia than measures of blunted affective expression.     

GABAA and GABAB receptors differentially regulate synaptic transmission in the auditory thalamo-amygdala pathway: an in vivo microiontophoretic study and a model

PURPOSE: Our purpose was to investigate the feasability of using sequential PCR and FISH analysis of single cells for preimplantation diagnosis. METHODS: Protocols for sequential PCR and FISH analysis of a single fibroblast (cell recycling) were optimized for six loci and the rates of allele specific dropout (ADO) were determined. RESULTS: Conditions that allow reliable genotyping of single cells in lysis buffer were not optimal for amplifying fibroblasts fixed to coverslips. After optimizing conditions, we observed a success rate of 85% for both analyses in sequential PCR-FISH experiments in single cells for the four loci studied. The individual success rates for each technique revealed a slightly higher rate for FISH (91-95%) than for PCR (85-87%) for single cells on coverslips. The presence of two hybridization signals in FISH experiments demonstrated that the failure to amplify both alleles from heterozygous cells on coverslips was due to true ADO, and not the loss of chromosomal material. The ADO rate observed on coverslips varied between 10 and 14%, which is significantly higher than that observed in solution, even after meticulous optimization. CONCLUSIONS: Sequential PCR and FISH analysis of single cells remains an attractive possibility. However, until the problem of the increased rate of ADO is resolved, cell recycling should be applied to clinical preimplantation genetic analysis.     

Characteristics of a highly labile human type 5 17beta-hydroxysteroid dehydrogenase

The overall disposition and hepatobiliary transport of BQ-123, an anionic cyclopentapeptide, and three analogs were examined in rats in vivo. Total body clearance (CLtotal) and biliary excretion clearance (CLbile, p) exhibited 4- to 8-fold differences between the compounds, with those for BQ-485 and compound A having the highest and lowest values, respectively. The CLbile, p values of BQ-485, BQ-123, and BQ-518 were almost equal to the CLtotal, suggesting that hepatobiliary transport is the major elimination pathway for these compounds. Hepatic uptake clearance (CLuptake, vivo) and biliary excretion clearance (CLbile, h/fT), which was defined for the hepatic unbound concentration, were separately determined to examine the hepatic uptake and excretion processes, respectively. Both the CLuptake, vivo and CLbile, h/fT of BQ-485 were higher than those of BQ-123, whereas the corresponding values for BQ-518 were similar to those for BQ-123. The CLuptake, vivo and CLbile, h/fT of compound A were, respectively, approximately two thirds and one half those of BQ-123, suggesting that the lower CLbile, p value is due to the low efficiency of both the uptake and excretion processes. The CLuptake, vivo of these four peptides in vivo was similar to the extrapolated values based on the carrier-mediated transport activity previously assessed in vitro in isolated rat hepatocytes. The primary active transport previously assessed in an in vitro study in canalicular membrane vesicles was also highest for BQ-485 and lowest for compound A, similar to CLbile, h/fT in vivo. Thus, the transporters on both the sinusoidal and canalicular membranes determine the efficiency of the peptide overall elimination from the circulation.     

Pharmacokinetics of medroxyprogesterone acetate after single and multiple injection of Cyclofem in Chinese women

The intake of fluorides with water, food, dental fluoride preparations, or in particular fluoride supplements, such as NaF tablets, may lead to dental fluorosis. In the present study conducted in a nonfluoridated area in Germany, developmental enamel defects were examined using the Modified Developmental Defects of Enamel Index (Mod DDE Index), which subdivides enamel defects into the categories demarcated (Mod DDE score 1) and diffuse (Mod DDE score 2) opacities and hypoplasia (Mod DDE score 3). 158 children, between 8.5 and 10 years old, were assigned to three examination groups, defined by three different fluoride tablet programs. The children in all three examination groups, F1, F2, and F3, had received 0.25 mg F-/day up to the age of 2 years, F1 and F3 from birth on, F2 beginning with the 7th month of life. F1 and F2 received 0.5 mg F-/day during the 3rd and 0.75 mg F-/day during the 4th and 5th year of life. For F3, beginning with the 3rd year of life, no further recommendations were made. 158 sociodemographically matched children living in a neighboring town served as controls and did not take part in any structured fluoride supplementation program. The proportions of children with Mod DDE scores 1, 2, or 3 at least in one index tooth were significantly higher in the examination groups (40%) than in the control group (20%). Also, the proportions of children with Mod DDE score 2 at least in one index tooth were significantly higher in the examination groups (18%) than in the control group (8%). The proportions of children with Mod DDE score 1 at least in one index tooth were 25% in the examination groups and 17% in the control group. No Mod DDE score 3 was found. Not more than 5% of the children in each group had 50% of their teeth with Mod DDE score 1, 2, or 3. The proportions of teeth per child with Mod DDE score 2 were significantly higher in the examination group than in the control group. While uncontrolled variables cannot be excluded, the observed differences between the experimental and control groups may be attributed to the ingestion of fluoride tablets in the experimental group.     

Survival of cells with bleomycin-induced chromosomal lesions in the cultured lymphocytes of lung cancer patients

OBJECTIVE: To investigate whether persistent T lymphocyte activation is a feature of steroid-resistant (SR) asthma and to study the inhibitory effects of dexamethasone and other immuno-inhibiting agents on PHA-induced proliferation of peripheral blood T lymphocytes from SR and steroid-sensitive (SS) asthmatics. MATERIAL AND METHODS: 15 SR and 15 SS asthmatics were studied. Serum levels of soluble interleukin-2 receptor (sIL-2R) were measured before and after prednisone therapy by an enzyme-linked immunosorbent assay. PHA-driven proliferative assay was performed to evaluate inhibition of T lymphocyte proliferation. RESULTS: Serum levels of sIL-2R were elevated in both patients with SR and SS asthma as compared with normal controls (P < 0.001). After a 7-day course of prednisone (20 mg/day), serum levels of sIL-2R decreased significantly in SS asthmatics (P < 0.001) but not in SR asthmatics (P > 0.1). Proliferation of T lymphocytes from the sensitive but not the resistant asthmatics was significantly (P < 0.002) inhibited by dexamethasone (10 mol/L), reflecting a shift of the dose-response curve. In contrast, oxymatrine and thymus-derived immunosuppressors inhibited proliferation of T lymphocytes to a similar degree between SR and SS asthmatics. CONCLUSIONS: The results suggest that persistent T lymphocyte activation due to a relative insensitivity of the cells to glucocorticoids is a feature of SR asthma. Immuno-inhibiting agents other than glucocorticoids may be of therapeutic benefit in patients with SR asthma.