Temporal relationship between elongation of the HIV type 1 glycoprotein 120 V2 domain and the conversion toward a syncytium-inducing phenotype.

The second and third variable domains (V2 and V3) of the human immunodeficiency virus type 1 (HIV-1) gp120 envelope molecule have been shown to be determinants of syncytium-inducing (SI) capacity. Previously we have reported evidence that increased length of the V2 domain and duplication or relocation of potential N-linked glycosylation sites in V2 might be used as prognostic markers for evolution toward an SI phenotype. Here, we used a PCR assay that discriminates a 6-nucleotide difference in the length of the V2 domain, with a sensitivity of 1 elongated V2 domain when present in a background of 125 to 625 short V2 domains.

Adverse long-term effects of reocclusion after coronary thrombolysis.

Objectives: This study sought to assess the long-term clinical consequences of reocclusion after coronary thrombolysis.

Background: After acute myocardial infarction successfully treated with thrombolysis, reocclusion occurs in approximately 30% of patients and leads to poorer in-hospital outcome. However, the long-term effects of reocclusion are unknown.

Perinatal exposure to polychlorinated biphenyls and dioxins through dietary intake.

Polychlorinated biphenyls (PCBs) and dioxins (polychlorinated dibenzo-p-dioxins and dibenzofurans) are potentially hazardous compounds. Since food is the major source (> 90%) for the accumulation of PCBs and dioxins in the human body, food habits in women determine the degree of fetal exposure and levels in human milk. In order to investigate an association between dietary intake and PCB and dioxin levels in human milk and PCB levels in maternal and cord plasma, the food intake of 418 Dutch women during pregnancy was recorded using semi-quantitative food frequency questionnaires.

Primary structure and tissue-specific expression of blue crab (Callinectes sapidus) metallothionein isoforms.

In aquatic animals, synthesis of the metal-binding protein metallothionein (MT) can be induced through exposure to elevated levels of metals in food or water. Whether the different routes of exposure lead to expression of different metallothionein isoforms in different tissues in unknown. In this study we examined the induction of metallothionein isoforms in the hepatopancreas and gills of the blue crab Callinectes sapidus.

Activated T cells can induce high levels of CTLA-4 expression on B cells.

Engagement of the TCR/CD3 complex together with ligation of CD28 by its counterstructures B7-1 (CD80) and B7-2 (CD86) on APC are required for mitogenic T cell activation. After activation, T cells not only express B7-1 and B7-2 molecules, but a second receptor for the B7 ligands, CTLA-4, can be found on their surfaces. We here show that B cells can be induced to express CTLA-4 on the plasma membrane.

Simple determination of human immunodeficiency virus type 1 syncytium-inducing V3 genotype by PCR.

Human immunodeficiency virus type 1 (HIV-1) phenotype variability plays an important role in the pathogenesis of AIDS. The presence of syncytium-inducing (SI) HIV-1 isolates in infected individuals is associated with a rapid decline of CD4+ T cells, rapid disease progression, and reduced survival time after AIDS diagnosis. The strong association between the SI capacity of HIV-1 and the presence of positively charged amino acid residues at positions 306 and/or 320 in the third variable domain (V3) of gp120 could here be confirmed in 97% of 402 primary HIV-1 isolates, indicating that the V3 genotype may be useful for prediction of the viral phenotype.

Characterization of the extracellular lipase, LipA, of Acinetobacter calcoaceticus BD413 and sequence analysis of the cloned structural gene.

The extracellular lipase from Acinetobacter calcoaceticus BD413 was purified to homogeneity, via hydrophobic-interaction fast performance liquid chromatography (FPLC), from cultures grown in mineral medium with hexadecane as the sole carbon source. The enzyme has an apparent molecular mass of 32 kDa on SDS-polyacrylamide gels and hydrolyses long acyl chain p-nitrophenol (pNP) esters, like pNP palmitate (pNPP), with optimal activity between pH 7.8 and 8.

Three-dimensional solution structure of Callinectes sapidus metallothionein-1 determined by homonuclear and heteronuclear magnetic resonance spectroscopy.

Metallothionein is a cysteine-rich metal-binding protein whose biosynthesis is closely regulated by the level of exposure of an organism to zinc, copper, cadmium, and other metal salts. The metallothionein from Callinectes sapidus is known to bind six divalent metal ions in two separate metal-binding clusters. Heteronuclear 1H-113Cd and homonuclear 1H-1H NMR correlation experiments have been used to establish that the two clusters reside in two distinct protein domains.

HIV-1 macrophage tropism is determined at multiple levels of the viral replication cycle.

The ability of HIV-1 to infect macrophages is thought to be essential in AIDS pathogenesis. We tested the ability of 19 primary virus isolates to infect monocyte-derived macrophages (MDM) from different donors. Two HIV-1 isolates were able to establish a productive infection in MDM from all donors tested, whereas eight completely lacked this capacity.

Influence of CD28 co-stimulation on cytokine production is mainly regulated via interleukin-2.

Interaction of CD28 with its ligand B7 plays an important role in the initiation of immune responses. The co-stimulatory signal generated by cross-linking of CD28 molecules results in enhanced T-cell proliferation and augmentation of cytokine production. In particular, mRNA levels of T-helper 1 (Th1)-type cytokines, such as interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) are reported to be strongly increased.

Differences in responsiveness to CD3 stimulation between naive and memory CD4+ T cells cannot be overcome by CD28 costimulation.

Activation of naive CD4+ T cells is essential for the induction of primary immune responses. However, this subset is less responsive to signaling via T cell receptor/CD3 (TcR/CD3) complex than memory CD4+ cells. For mitogenic activation of T cells, in addition to triggering of the TcR/CD3 complex, costimulatory signals are required that can be generated by surface structures present on the antigen-presenting cells.

Simultaneous regulation of CD2 adhesion and signaling functions by a novel CD2 monoclonal antibody.

Accessory molecules on T cells can support adhesion and transduce agonistic signals that facilitate Ag receptor-induced T cell activation. The T cell differentiation Ag CD2 may exert both functions, as has been amply demonstrated in studies with CD2 mAbs. In addition, experiments in which either purified ligand (CD58) or transfected CD2 and CD58 molecules were used have confirmed this notion.

Controlled insect-sting challenge in 55 patients: correlation between activation of plasminogen and the development of anaphylactic shock.

The pathogenesis of anaphylactic shock is not completely understood. Mast cell degranulation products may stimulate endothelial cells, leading to activation of fibrinolytic and coagulation systems. We investigated the activation of these systems in insect-sting anaphylaxis.

Regulation of CD27 expression on subsets of mature T-lymphocytes.

CD27, a lymphocyte-specific member of the TNF/NGF-R family, is expressed on the majority of peripheral blood T cells. Activation of T cells via TCR/CD3 induces high CD27 surface expression and the release of a soluble extracellular part of the molecule. After prolonged activation in vitro, CD27 becomes gradually switched off.

A putative glutathione-binding site in CdZn-metallothionein identified by equilibrium binding and molecular-modelling studies.

Glutathione (GSH) has been found to form a complex with both vertebrate and invertebrate copper-metallothionein (CuMT) [Freedman, Ciriolo and Peisach (1989) J. Biol. Chem.

A checklist for evaluating ergonomic risk factors associated with upper extremity cumulative trauma disorders.

A two-page checklist for determining the presence of ergonomic risk factors associated with the development of upper extremity cumulative trauma disorders (e.g., repetitiveness, local mechanical contact stresses, forceful manual exertions, awkward postures, and hand tool usage) was developed and evaluated as part of a joint labour-management ergonomics intervention programme.

Congenital quadricuspid aortic valve.

Two patients with a quadricuspid aortic valve are described, one of them with concomitant juxtaposed coronary orifices facing the right hand facing sinus. The etiology and incidence of this congenital anomaly will be discussed.

Induction of metallothionein mRNA in the blue crab (Callinectes sapidus) after treatment with cadmium.

1. Dietary treatment of blue crabs with cadmium led to an increase of cadmium metallothionein in the hepatopancreas. 2.

Hemocyanin synthesis in the blue crab Callinectes sapidus.

1. The synthesis of hemocyanin in the blue crab, Callinectes sapidus, was investigated by molecular techniques. 2.

Activation patterns of coagulation and fibrinolysis in baboons following infusion with lethal or sublethal dose of Escherichia coli.

Administration of low doses endotoxin or tumor necrosis factor (TNF) in human experimental models for sepsis results in transient activation of both coagulation and fibrinolysis and subsequent inhibition of the fibrinolytic system by plasminogen activator inhibitor type 1 (PAI-1). We have investigated in a baboon model for sepsis, whether administration of a lethal or sublethal dose of living E. coli could induce similar activation patterns.

Maturation- and differentiation-dependent responsiveness of human CD4+ T helper subsets.

The human CD45R0+ (memory) CD4+ T cell population can be subdivided into a large (82%) CD27+ and a small (18%) CD27- subset. Within the CD45R0+CD27- subset, cells accumulate that have been persistently stimulated by Ag in vivo. As an apparent consequence, TLC with a differentiated functional phenotype, producing either high levels of IFN-gamma (Th1-like), high levels of IL-4 (Th2-like) or high amounts of both these cytokines (here referred to as Thx) can primarily be generated from the CD27- memory CD4+ T cell subset.

In vivo magnetic resonance imaging of the blue crab, Callinectes sapidus: effect of cadmium accumulation in tissues on proton relaxation properties.

Nuclear magnetic resonance imaging (MRI) has been used to visualize the internal anatomy of a living blue crab. The resolution obtained in these studies was sufficient to distinguish individual organs by the differences in their proton densities and proton relaxation properties. T1 (spin-lattice relaxation time)-weighted imaging revealed the lipid-rich nature of the hepatopancreas and gonadal tissue.

Growth of the hypoplastic aortic arch after simple coarctation resection and end-to-end anastomosis.

Surgical treatment of a hypoplastic aortic arch associated with an aortic coarctation is controversial. The controversy concerns the claimed need to surgically enlarge the diameter of the hypoplastic arch, in addition to resection and end-to-end anastomosis. The purpose of this prospective study is to determine the fate of the hypoplastic aortic arch after resection of the aortic coarctation and end-to-end anastomosis.

The TACPyAT repeats in the chalcone synthase promoter of Petunia hybrida act as a dominant negative cis-acting module in the control of organ-specific expression.

Analysis of the expression of the GUS reporter gene driven by various regions of the Petunia hybrida chalcone synthase (chsA) promoter revealed that the developmental and organ-specific expression of the chsA gene is conferred by a TATA proximal module located between -67 and -53, previously designated as the TACPyAT repeats. Histochemical analysis of GUS reporter gene expression revealed that the organ-specific 67 bp promoter fragment directs the same cell-type specificity as a 530 bp promoter, whereas additional enhancer sequences are present within the more TATA distal region. Moreover, the region between -800 and -530 is also involved in extending the cell-type specificity to the trichomes of flower organs and of young seedlings.

Interleukin-6 release and the acute-phase reaction in patients with acute myocardial infarction: a pilot study.

We investigated the potential role of interleukin-6 as a mediator of the acute-phase reaction (APR) in patients with acute myocardial infarction. Of the six patients studied, five demonstrated increased plasma interleukin-6 levels. Interleukin-6 levels began to increase at 14 hours (mean; range = 8 to 20 hours) after the initial complaints and reached maximal levels of 28 to 250 U/mL (normal values less than 10 U/mL) after 36 hours (mean; range = 24 to 52 hours).