Comparison of Vpu sequences from diverse geographical isolates of HIV type 1 identifies the presence of highly variable domains, additional invariant amino acids, and a signature sequence motif common to subtype C isolates.

We compared the Vpu sequences from 101 strains of HIV-1 isolated from diverse geographical regions and various subtypes in order to identify regions of high variability, and those amino acid residues that were highly conserved or invariant. In addition to the highly conserved casein kinase II (CKII) phosphorylation sites, our analysis identified additional invariant residues in the transmembrane domain and in the first and second alpha-helical domains. Our analysis revealed that all subtype C sequences had a conserved LRLL motif at the C terminus that was also found in A/C intersubtype recombinants.

A molecular clone of simian-human immunodeficiency virus (DeltavpuSHIV(KU-1bMC33)) with a truncated, non-membrane-bound vpu results in rapid CD4(+) T cell loss and neuro-AIDS in pig-tailed macaques.

We report on the role of vpu in the pathogenesis of a molecularly cloned simian-human immunodeficiency virus (SHIV(KU-1bMC33)), in which the tat, rev, vpu, env, and nef genes derived from the uncloned SHIV(KU-1b) virus were inserted into the genetic background of parental nonpathogenic SHIV-4. A mutant was constructed (DeltavpuSHIV(KU-1bMC33)) in which 42 of 82 amino acids of Vpu were deleted. Phase partitioning studies revealed that the truncated Vpu was not an integral membrane protein, and pulse-chase culture studies revealed that cells inoculated with DeltavpuSHIV(KU-1bMC33) released viral p27 into the culture medium with slightly reduced kinetics compared with cultures inoculated with SHIV(KU-1bMC33).

EGF receptors of hepatocytes from rats treated with phenobarbital are sensitized to down-regulation by phenobarbital in culture.

Hepatocytes from Fisher 344 rats treated with the liver tumor promoter phenobarbital (PhB; 0.1% in the drinking water, 2-3 months) exhibit reduced epidermal growth factor (EGF) binding and EGF-induced mitogenesis in culture. Similar responses are induced by >1 mM PhB added to the culture medium of hepatocytes from untreated rats.

Transforming growth factor-beta overrides the adhesion requirement for surface expression of alpha(5)beta(1) integrin in normal rat kidney fibroblasts. A necessary effect for induction of anchorage-independent growth.

We have previously shown that the expression of alpha(5)beta(1) integrin on the cell surface is dependent upon cell adhesion to the extracellular matrix, and we report here that transforming growth factor-beta (TGF-beta) overcomes this requirement in normal rat kidney (NRK) fibroblasts. Thus, suspended NRK cells treated with TGF-beta show levels of surface alpha(5)beta(1) integrin that are equivalent to those seen in adherent cells. Moreover, several experiments showed that this effect is necessary for the induction of anchorage-independent growth by TGF-beta.

The integrin alpha v beta 6 binds and activates latent TGF beta 1: a mechanism for regulating pulmonary inflammation and fibrosis.

Transforming growth factor beta (TGF beta) family members are secreted in inactive complexes with a latency-associated peptide (LAP), a protein derived from the N-terminal region of the TGF beta gene product. Extracellular activation of these complexes is a critical but incompletely understood step in regulation of TGF beta function in vivo. We show that TGF beta 1 LAP is a ligand for the integrin alpha v beta 6 and that alpha v beta 6-expressing cells induce spatially restricted activation of TGF beta 1.

Cell cycle control of chromosomal DNA replication.

Accurate replication and segregation of chromosomal DNA is essential for high-fidelity transmission of genetic information from generation to generation. Eukaryotic cells typically replicate by first duplicating their chromosomes during the S phase followed by their segregation between two daughter cells during the M phase. Over recent years, advances in our understanding of this process at the molecular level have been incredibly rapid.

The dietitians' philosophy and practice in multidisciplinary weight management.

Dietitians are developing a philosophy and a practice protocol of weight management. A professional philosophy of weight management addresses questions about the social, psychological, and biological spectra of weight management: Should overweight be considered in terms of size acceptance or gluttony and sloth? How should emotional overeating and obsessive restriction be managed? Should obesity be considered a chronic disease, or should the idea that health at every size is possible be espoused? A professional practice protocol addresses another set of questions: Is obesity to be viewed as a short-term and long-term health challenge? Regarding the spectrum of antiobesity agents and antidieting approaches of weight management, what professional position and individual practice will be adopted? Should professional contact with patients be continuous or aimed toward self-care? What measures of successful outcomes will be used: weight change or life quality improvement? How should professional responsibility be balanced with personal concerns about eating and health behaviors that affect body weight? What are examples of closing the gap between the vision and the reality of the roles and goals of the dietitian on a weight management team? Dietitians are translating philosophy into practice. Because dietary control alone has a record of limited success in weight loss and less success in maintaining weight loss, the dietitian's expanded role includes helping patients manage weight with coping skills, motivation techniques, physical activity, and food behavior change.

Exacerbation of atopic dermatitis after bacillus Calmette-Guérin vaccination.

In two children with atopic dermatitis, routine vaccination with bacillus Calmette-Guérin (BCG) was followed by severe exacerbation of skin disease. If the sequence is cause and effect, a possible mechanism is stimulation of a Th2 lymphocyte cytokine profile by the vaccine, with migration of activated lymphocytes to inflamed skin. In children with active atopic dermatitis, BCG vaccination is best deferred until remission.

Recovery and relapse in geriatric depression after treatment with antidepressants and ECT in a medical-psychiatric population.

The objective of this naturalistic, longitudinal treatment outcome study was to determine relapse rates in geriatric depression following treatment with antidepressants and electroconvulsive therapy in a medical-psychiatric population. Thirty-nine elderly patients (average age 71 years) with unipolar major depression were treated with either antidepressants (AD) or, if resistant to AD treatment, ECT followed by maintenance antidepressants. Patients were monitored over 18 months, and relapse rates were closely determined using the Longitudinal Interval Follow-up Evaluation (LIFE) and the 21-item Hamilton Depression Rating Scale.

Lithium intolerance in a medical-psychiatric population.

This pilot study was designed to explore the tolerance and efficacy of lithium as an adjunctive prophylactic agent when added to maintenance antidepressant regimens following an episode of depression in an older medical-psychiatric population. In a randomized controlled trial, 27 depressed patients had either lithium carbonate or placebo added to their maintenance antidepressant (AD) regimen following an index episode of depression. Of 17 patients who received lithium carbonate, 76% (13/17) were unable to tolerate this agent for the duration of the study because of side effects (e.

Characterization of Cdc47p-minichromosome maintenance complexes in Saccharomyces cerevisiae: identification of Cdc45p as a subunit.

Cdc47p is a member of the minichromosome maintenance (MCM) family of polypeptides, which have a role in the early stages of chromosomal DNA replication. Here, we show that Cdc47p assembles into stable complexes with two other members of the MCM family, Cdc46p and Mcm3p. The assembly of Cdc47p into complexes with Cdc46p does not appear to be cell cycle regulated, making it unlikely that these interactions per se are a rate-limiting step in the control of S phase.

Resistance training in children and youth: a meta-analysis.

This research used meta-analysis to examine the effect of resistance training on children and youth. Studies investigating the effects of various forms of resistance training in participants of ages less than 18 years were analyzed. Effects sizes (ES) were calculated by gender, age group (boys ages > or = 16 years and girls ages > or = 14 years were defined as older), training (isokinetic, isometric, isotonic), and design type (pretest-posttest or experimental-control).

Cdc45p assembles into a complex with Cdc46p/Mcm5p, is required for minichromosome maintenance, and is essential for chromosomal DNA replication.

We report the isolation and characterization of CDC45, which encodes a polypeptide of 650 amino acids that is essential for the initiation of chromosomal DNA replication in the budding yeast, Saccharomyces cerevisiae. CDC45 genetically interacts with at least two members of the MCM (minichromosome maintenance) family of replication genes, CDC46 and CDC47, which are proposed to perform a role in restricting initiation of DNA replication to once per cell cycle. Like mutants in several MCM genes, alleles of CDC45 also show a severe minichromosome maintenance defect.

Phosphorylation of MCM4 by cdc2 protein kinase inhibits the activity of the minichromosome maintenance complex.

In eukaryotes, tight regulatory mechanisms ensure the ordered progression through the cell cycle phases. The mechanisms that prevent chromosomal DNA replication from taking place more than once each cell cycle are thought to involve the function of proteins of the minichromosome maintenance (MCM) family. Here, we demonstrate that Xenopus MCM4, a member of the MCM protein family related to Spcdc21/ ScCDC54, is part of a large protein complex comprising several other MCM proteins.

The yeast tribrid system--genetic detection of trans-phosphorylated ITAM-SH2-interactions.

Protein-protein interactions are often dependent on the post-translational modification of one component of a complex. To facilitate the study of these interactions in signal transduction, we have developed the yeast tribrid system, a modification of the yeast two-hybrid system. We demonstrate that the interactions are dependent upon the presence of a tyrosine kinase, an SH2 domain and a tyrosine containing substrate.

Cell adhesion to extracellular matrix regulates the life cycle of integrins.

The expression of alpha 5 beta 1 integrin on the surface of fibroblasts requires adhesion to substratum. We have examined the basis for this adhesion-dependent surface expression by comparing the life cycle of integrins in parallel cultures of adherent and nonadherent cells. Results of biosynthetic labeling experiments in NRK fibroblasts showed that the synthesis and biosynthetic processing of the beta 1 integrin subunit proceed in the absence of cell attachment; however, when examining the behavior of preexisting cell surface integrins, we observed that the alpha beta 1 integrins are internalized and degraded when adhesion to substratum is blocked.

Human shoulder tendon biopsy samples in organ culture produce procollagenase and tissue inhibitor of metalloproteinases.

Objective: To investigate the production of the matrix metalloproteinase (MMP), collagenase (MMP-1), and its natural inhibitor, the tissue inhibitor of metalloproteinases (TIMP) by diseased human tendon samples in organ culture.

Methods: Portions of tendons were excised from the shoulders of patients undergoing shoulder surgery, classified as either proximal to the lesion (abnormal) or distal to the lesion (normal) according to their macroscopic appearance at surgery, and placed in organ culture for periods of up to 28 days. The release of collagenase and TIMP activity in the conditioned culture medium was measured.

Cell cycle-regulated transcription of the CLB2 gene is dependent on Mcm1 and a ternary complex factor.

Clb2 is the major B-type mitotic cyclin required for entry into mitosis in the budding yeast Saccharomyces cerevisiae. We showed that accumulation of CLB2 transcripts in G2 cells is controlled at the transcriptional level and identified a 55-bp upstream activating sequence (UAS) containing an Mcm1 binding site as being necessary and sufficient for cell cycle regulation. Sequences within the cell cycle-regulated UAS were shown to bind Mcm1 in vitro, and mutation which abolished Mcm1-dependent DNA binding activity eliminated cell cycle-regulated transcription in vivo.

Cell cycle-regulated nuclear import and export of Cdc47, a protein essential for initiation of DNA replication in budding yeast.

The CDC47 gene was isolated by complementation of a cdc47 temperature-sensitive mutant in Saccharomyces cerevisiae and was shown to encode a predicted polypeptide, Cdc47, of 845 aa. Cdc47 belongs to the Cdc46/Mcm family of proteins, previously shown to be essential for initiation of DNA replication. Using indirect immunofluorescence microscopy and subcellular fractionation techniques, we show that Cdc47 undergoes cell cycle-regulated changes in its subcellular localization.

Cdc54 belongs to the Cdc46/Mcm3 family of proteins which are essential for initiation of eukaryotic DNA replication.

CDC54 is a gene essential for initiation of DNA replication in Saccharomyces cerevisiae, and which is known to genetically interact with other regulators of the S-phase, including CDC46. We describe the isolation and sequencing of CDC54 and show that it encodes a protein structurally related to Cdc46p, Mcm2p and Mcm3p by the presence of a conserved domain of 145 amino acids which is internal to each polypeptide. This conserved domain resembles the DEAD box of RNA helicases and is similar to the conserved domain associated with a group of transcription and replication factors with known or assumed DNA-dependent ATPase activity, suggesting it may be involved in nucleic-acid recognition.