Bovine immunodeficiency virus tat gene: cloning of two distinct cDNAs and identification, characterization, and immunolocalization of the tat gene products

cDNAs encoding the bovine immunodeficiency virus (BIV) transactivator gene (tat) were cloned from virally infected cells and characterized. BIV expresses two distinct tat mRNAs composed of three exons that are derived by alternative splicing. The BIV tat mRNA splice variants encode Tat proteins of 103 (Tat103) and 108 (Tat108) amino acids. The Tat103 coding region is specified only by exon 2, while that of Tat108 is specified by a truncated exon 2 and the first 30 nt of exon 3. Thus, the first 98 amino acids of each Tat are identical, and have amino terminal, cysteine-rich, conserved core, basic, and carboxyl-terminal domains similar to Tats encoded by primate lentiviruses. BIV-infected bovine cells express a 14-kDa phosphorylated Tat protein identical in size to recombinant Tat expressed in bacteria. BIV Tat was shown to localize exclusively in the nucleoli of virally infected and Tat-expressing cells. Reporter gene assays indicated that Tat103 and Tat108 can strongly transactivate the BIV long terminal repeat (LTR) in virally permissive canine Cf2Th and nonpermissive HeLa and mouse NIH 3T3 cells, but not in permissive lapine EREp cells. However, an intact BIV tat gene is required for viral replication in both Cf2Th and EREp cells. Strong LTR activation by BIV Tat requires a TAR (transactivation responsive) element delimited by viral nt +1 to +31 and the Tat basic domain. BIV Tat strongly cross-transactivates the HIV-1 LTR in a TAR-dependent manner in Cf2Th, but not in EREp, HeLa, or NIH 3T3 cells. In contrast, strong, TAR-dependent cross-transactivation of the BIV LTR by HIV-1 Tat could not be demonstrated in any of these cell types. In Cf2Th cells Tat108 effects a moderately stronger transactivation of the BIV LTR than Tat103, indicative of a functional difference in BIV Tat proteins encoded by the mRNA splice variants. The present studies demonstrate that BIV Tat parallels the primate lentiviral Tats in structure and biochemistry but is not interchangeable with the latter.     

Improving adherence to fluid restrictions in male hemodialysis patients: A comparison of cognitive and behavioral approaches.

Compared a cognitive intervention and a behavioral intervention to determine their relative effectiveness in reducing interdialytic weight gain (IWG) among 8 adult male hemodialysis patients. The behavioral model consisted of positive reinforcement, shaping, and self-monitoring. The cognitive model consisted of a counseling intervention designed to modify health beliefs. In 3 studies, both interventions produced immediate reductions in IWG. However, the behavioral intervention was superior to the cognitive intervention in producing maintenance of reduced weight gain. Combining the interventions resulted in no improvement over the behavioral intervention alone. Continuation of self-monitoring procedures produced maintenance of improvements up to 2 mo posttreatment. With the exception of the barriers dimension, health beliefs did not change along with adherence behavior changes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extraction and replacement of permanent pacemaker leads through occluded vessels: use of extraction sheaths as conduits--balloon venoplasty as an adjunct

Patients (pts) may present for lead extraction with symptomatic or asymptomatic subclavian vein or superior vena cava thrombosis. Replacement of permanent pacemaker leads (PPLs) in these pts may be difficult and may require accessing a new site. We examined the utility of replacing PPLs through completely occluded vessels using extraction sheaths as conduits through the total occlusion. Over six years, a total of 210 atrial and/or ventricular PPLs were extracted from 137 pts. Two pts presented with angiographically documented thrombotic occlusion of the subclavian vein. One additional pt. who had presented with a superior vena cava (SVC) syndrome, had a totally occluded innominate vein and SVC occlusion. Balloon venoplasty was used as an adjunct to dilate the SVC. In all pts, after PPLs were removed via a subclavian extraction sheath through the occluded vessel, the retained sheath was used to place a guide wire, then a peel away dilating sheath, to insert new PPLs, in each case on the side of total venous occlusion. Seven PPLs and two lead fragments were extracted, and five new PPLs replaced, ipsilateral to the venous occlusion. These data show that extraction of PPLs through thrombosed veins may be performed successfully and may not require replacing the leads through a new site. This technique spares the pt the need to access the opposite subclavian vein, and it avoids an excessive number of PPLs in the subclavian vein and SVC. The procedure illustrates an efficient means to reintroduce new PPLs with the potential to reduce associated morbidity, since repeat puncture of the subclavian vein is not required. Safety of the procedure as a whole must be considered with regard to the known risks of lead extraction, some complications of which may be substantial using current techniques.     

Prospective study of high grade anal squamous intraepithelial neoplasia in a cohort of homosexual men: influence of HIV infection, immunosuppression and human papillomavirus infection

OBJECTIVE: To determine the risk of developing high grade anal squamous intraepithelial neoplasia (HG-AIN) in relation to HIV infection and immunosuppression, after controlling for the effects of human papillomavirus (HPV) infection. DESIGN: Prospective cohort study of 158 HIV-seropositive and 147 HIV-seronegative homosexual men presenting to a community-based clinic with initially negative anal cytologic and colposcopic findings. METHODS: Subjects completed self-administered questionnaires, underwent cytologic screening, and standardized unaided and colposcopic examination of the proximal anal canal for presence of abnormalities suggestive of AIN. Anal specimens were screened for HPV DNA. RESULTS: HG-AIN developed in eight (5.4%) and 24 (15.2%) HIV-seronegative and -seropositive men, respectively. Risk of HG-AIN among HIV-seronegative men was associated with detection of anal HPV types 16 or 18 by Southern transfer hybridization (STH), detection of HPV 16 or 18 at the lower levels by polymerase chain reaction but not by STH, and with number of positive HPV tests; HG-AIN risk among HIV-seropositive men was associated with detection of HPV 16 or 18 only by STH, detection of HPV types other than 16 or 18, CD4 count < or = 500 x 10(6)/l, and number of positive HPV tests. HIV-induced immunosuppression remained an independent predictor of HG-AIN after adjusting for type and level of detection of HPV; HIV infection predicted HG-AIN risk after adjustment for number of positive HPV tests. CONCLUSIONS: The association of HG-AIN with HIV, independent of HPV type, level of HPV detection and number of positive HPV tests, suggests that this increased risk cannot be entirely explained by an effect of HIV on HPV detection. Future studies focusing on factors more specific to the local microenvironment in the anal canal should help clarify these issues.     

In vitro drug sensitivity and clinical aspects of Plasmodium falciparum malaria in African children

OBJECTIVE: To compare body mass index (BMI), lipid, lipoprotein and apolipoprotein concentrations according to the Hind III and Pvu II restriction polymorphisms of the LPL gene in obese subjects. DESIGN: Cross sectional study of anthropometric and lipid variables in relation to genetic factors. SETTING: Nutrition Outpatient Clinic of Bichat Hospital in Paris, France. SUBJECTS: 236 unrelated patients (162 women and 74 men) were selected on the basis of 120% of ideal body weight. MAIN OUTCOME MEASURES: Anthropometry (body mass index, waist to hip ratio), blood lipids and lipoproteins, determination of LPL Hind III and Pvu II genotypes. RESULTS: Digestion with Hind III generated two alleles, H1 (absence of cutting site) and H2 (presence of cutting site), with frequencies of 0.30 and 0.70 respectively. Digestion with Pvu II generated two alleles P1 and P2 with frequencies of 0.49 and 0.51 respectively. The Hind III polymorphism was significantly associated with body mass index (BMI) (P < 0.05). The H2H2 genotype was associated with hypertriglyceridemia: 68% of the hypertriglyceridemic subjects have the H2H2 genotype vs 43% of the normotriglyceridemic group (P < 0.05). Plasma triglyceride levels varied significantly among the Hind III genotypes, H2H2 genotype having the highest total and VLDL-triglyceride levels; the Hind III polymorphism also showed a significant association with HDL2-cholesterol. These associations were only seen in women and were not explained by the variations in BMI and age. No significant associations were found between lipid traits and Pvu II genotype. CONCLUSION: These results suggest that genetic variation in the LPL gene in obese subjects is associated with hypertriglyceridemia and possibly with a predisposition to obesity.     

mago nashi mediates the posterior follicle cell-to-oocyte signal to organize axis formation in Drosophila

Establishment of the anteroposterior and dorsoventral axes in the Drosophila egg chamber requires reciprocal signaling between the germ line and soma. Upon activation of the Drosophila EGF receptor in the posterior follicle cells, these cells signal back to the oocyte, resulting in a reorganization of the oocyte cytoplasm and anterodorsal migration of the oocyte nucleus. We demonstrate that the gene mago nashi (mago) encodes an evolutionarily conserved protein that must be localized within the posterior pole plasm for germ-plasm assembly and Caenorhabditis elegans mago is a functional homologue of Drosophila mago. In the absence of mago+ function during oogenesis, the anteroposterior and dorsoventral coordinates of the oocyte are not specified and the germ plasm fails to assemble.     

Common patterns of genetic evolution in human solid tumors

Microscopy is a basic tool for cell biologists. Recent progress of electronics and computer science made powerful methodologies for digital processing of microscopic images easily available. These methods allowed impressive increase of the power of conventional microscopy. Dramatic image enhancement may be achieved by combination of filtering techniques, computer-based deblurring and contrast enhancement. Quantitative treatment of digitized images allows absolute determination of the density of different components of the observed sample, including antigens, intracellular calcium and pH. Morphometric studies are also greatly facilitated by image processing techniques. The capture of fast phenomena may be performed by transfer of small portion of microscopic images into computer memory as well as particular use of confocal microscopy. Finally, improved display of experimental data through coded colors or other procedures may enhance the amount of information that can be conveyed by visual examination of microscopical images. The purpose of the present review is to describe the basic principles of image processing and exemplify the power of this approach with a variety of illustrated applications to conventional, fluorescence or electron microscopy as well as confocal microscopy.