Synthetic peptides from a conserved region of gp120 induce broadly reactive anti-HIV responses.

In our efforts to identify products that might be used for active immunotherapy in human immunodeficiency virus (HIV) infection, we have studied synthetic peptides derived from the CD4 attachment site of gp120. Two peptides have emerged with particularly interesting properties. The first (B138) is linear and spans the envelope residues 421-438; the second (1005/45) encompasses amino acids 418-445 and is cyclized by way of a disulphide bond joining its terminal cysteines. Both species have been shown to inhibit syncytial formation in a conventional bioassay, B138 being the most efficient. Both peptides elicit high titres of anti-peptide antibodies in immunized mice, rabbits and goats, with titres exceeding 1:10(5) in many cases. A substantial portion of this response is directed against gp120 as determined by enzyme-linked immunosorbent assay (ELISA). Analysis by flow cytometry has demonstrated that the antisera are broadly reactive with multiple diverse strains of HIV. The anti-gp120 activity of the anti-peptide antiserum was further confirmed by radioimmuno-precipitation (RIP) assays. Furthermore, RIP analysis and inhibition experiments in a GD4-gp120 binding assay have revealed that anti-peptide sera contain antibodies directed against the CD4 attachment site on gp120 and interfere with this receptor-ligand interaction.     

Controlled elimination of intracellular H(2)O(2): regulation of peroxiredoxin, catalase, and glutathione peroxidase via post-translational modification

The predominant enzymes responsible for elimination of hydrogen peroxide (H(2)O(2)) in cells are peroxiredoxins (Prxs), catalase, and glutathione peroxidases (GPxs). Evidence suggests that catalytic activities of certain isoforms of these H(2)O(2)-eliminating enzymes are extensively regulated via posttranslational modification. Prx I and Prx II become inactivated when phosphorylated on Thr(90) by cyclin B-dependent kinase Cdc2. In addition, the active-site cysteine of Prx I-IV undergoes a reversible sulfinylation (oxidation to cysteine sulfinic acid) in cells. Desulfinylation (reduction to cysteine) is achieved by a novel enzyme named sulfiredoxin. c-Abl and Arg nonreceptor protein tyrosine kinases associate with catalase in cells treated with H(2)O(2) by mechanisms involving the SH3 domains of the kinases and the Pro(293)PheAsnPro motif of catalase and activate catalase by phosphorylating it on Tyr(231) and Tyr(386). Similarily, GPx1 is activated by c-Abl- and Arg-mediated phosphorylation. The tyrosine phosphorylation is critical for ubiquitination-dependent degradation of catalase.     

Evidence that productive rearrangements of TCR γ genes influence the commitment of progenitor cells to differentiate into αβ or γδ T cells

Two models have been considered to account for the differentiation of γδ and αβ T cells from a common hematopoietic progenitor cell. In one model, progenitor cells commit to a lineage before T cell receptor (TCR) rearrangement occurs. In the other model, progenitor cells first undergo rearrangement of TCRγ, δ, or both genes, and cells that succeed in generating a functional receptor commit to the γδ lineage, while those that do not proceed to attempt complete β and subsequently α gene rearrangements. A prediction of the latter model is that TCRγ rearrangements present in αβ T cells will be nonproductive. We tested this hypothesis by examining Vγ2-Jγ1Cγ1 rearrangements, which are commonly found in αβ T cells. The results indicate that Vγ2-Jγ1Cγ1 rearrangements in purified αβ T cell populations are almost all nonproductive. The low frequency of productive rearrangements of Vγ2 in αβ T cells is apparently not due to a property of the rearrangement machinery, because a transgenic rearrangement substrate, in which the Vγ2 gene harbored a frame-shift mutation that prevents expression at the protein level, was often rearranged in a productive configuration in αβ T cells. The results suggest that progenitor cells which undergo productive rearrangement of their endogenous Vγ2 gene are selectively excluded from the αβ T cell lineage.     

Malignant granular cell tumor at the retrotracheal space

We report a case of an extremely rare neoplasm, malignant granular cell tumor (MGCT). The patient was a 21-year-old woman, who was 5 months pregnant. The tumor occurred in the retrotracheal space, extending from the level of the larynx to the thoracic inlet. In addition, there were multiple, variable-sized tumor nodules within both lung fields on chest CT scan. Histologically, tissue biopsied from the periphery of the tumor consisted of solid sheets of large ovoid cells with ample, eosinophilic cytoplasm, eccentric nuclei, and prominent nucleoli. Each cell showed slight atypism of the nuclei. There was a focal necrosis at the periphery of the lesion. These cells stained strongly for S-100 protein, neuron-specific enolase (NSE) and CD68. On electron microscopy, the tumor cells contained autophagic vacuoles. The patient refused further treatment and died 7 months later. The exact cause of death was not known. Until now, the diagnosis of MGCTs has been made only when metastasis and an aggressive clinical course are identified, although some observers advocate that some histologic features such as nuclear pleomorphism, necrosis, and the presence of any mitotic activity are indicative of malignancy. These histologic findings are not easily detectable in every case of MGCT, as in our case. So the diagnosis of a MGCT should be considered in cases with aggressive clinical findings and some histologic features, such as necrosis, nuclear atypism, and mitotic activities, which could suggest the malignant behavior of this neoplasm.     

Caffeine and histamine-induced oscillations of K(Ca) current in single smooth muscle cells of rabbit cerebral artery

In the present experiment, we characterized the intracellular Ca²⁺ oscillations induced by caffeine (1 mM) or histamine (1–3 M) in voltage-clamped single smooth muscle cells of rabbit cerebral (basilar) artery. Superfusion of caffeine or histamine induced periodic oscillations of large whole-cell K⁺ current with fairly uniform amplitudes and intervals. The oscillatory K⁺ current was abolished by inclusion of ethylenebis(oxonitrilo)tetraacetate (EGTA, 5 mM) in the pipette solution. Caffeine- and histamine-induced periodic activation of the large-conductance Ca²⁺-activated K⁺ [K_(Ca)] channel was recorded in the cell-attached patch mode. These results suggest that the oscillations of K⁺ current are carried by the K_(Ca) channel and reflect the oscillations of intracellular Ca²⁺ concentration ([Ca²⁺]_i). Ryanodine (1–10 M) abolished both caffeine- and histamine-induced oscillations. Caffeine- induced oscillations were abolished by the sarcoplasmic reticulum Ca²⁺-adenosine 5-triphosphatase (Ca²⁺-ATPase) inhibitor, cyclopiazonic acid (10 M), and a high concentration of caffeine (10 mM). Inclusion of heparin (3 mg/ml) in the pipette solution blocked histamine-induced oscillations, but did not block caffeine-induced oscillations. By the removal of extracellular Ca²⁺, but not by the addition of verapamil and Cd²⁺, the caffeine-induced oscillations were abolished. Increasing Ca²⁺ influx rate increased the frequencies of caffeine-induced oscillations. Spontaneous oscillations were also observed in cells that were not superfused with agonists, and had similar characteristics to the caffeine-induced oscillations. From the above results, it is concluded, that in smooth muscle cells of the rabbit cerebral (basilar) artery, ryanodine-sensitive Ca²⁺-induced Ca²⁺ release pools play key roles in the generation of caffeine- and histamine-induced intracellular Ca²⁺ oscillations.     

The effect of an intercollegiate soccer game on maximal power performance.

The effect of a competitive soccer match on maximal power performance was assessed on 19 members of an NCAA Division III female soccer team. Performance testing occurred within 24 hours prior to the game (Pre), immediately postgame (IP), and 24 hours postgame (24P). Each subject performed a squat jump (SJ) and countermovement jump (CMJ). Comparisons between starters (n = 10) and nonstarters (n = 9) revealed no between-group differences in power performance at IP, but starters were found to have significantly lower power and force measures at 24P than nonstarters. There were significant correlations between playing time and peak force during the SJ at 24P (r = -0.47), and between playing time and peak power during the SJ at IP (r = -0.57) and 24P (r = -0.51), and during the CMJ at IP (r = -0.49). Comparisons between different positions revealed no differential fatigue patterns. Results of this study show that power performance appears to be maintained for the duration of a soccer match but declines significantly within 24 hours after the match. Position played does not appear to affect performance decrements seen at 24 hours postmatch.     

The effect of Jeo Dang-Tang on cytokines production in the patients with cerebral infarction

The herbal formulation "Jeo Dang-Tang" (JDT) has long been used for various cerebrovascular diseases. However, very little has scientific investigation been carried out. The aim of the present study is to investigate the effect of JDT on the production of various cytokines in the patients with cerebral infarction (CI). Peripheral blood mononuclear cells (PBMC) obtained from the patients with CI were cultured for 24h in the presence or absence of lipopolysaccharide (LPS) or phytohemagglutinin (PHA). The amount of interleukin (IL)-4, IL-10 and transforming growth factor (TGF)-1beta, in culture supernatant, was significantly increased in the JDT, LPS or PHA treated cells compared to unstimulated cells (P < 0.05). We also show that increased IL-4, and IL-10 level by LPS or PHA was significantly inhibited by JDT in a dose-dependent manner. Maximal inhibition rate of IL-4 and IL-10 production by JDT was 45 +/- 2% and 51 +/- 5% for LPS-stimulated cell and 41.5 +/- 3% and 70.8 +/- 2% for PHA-stimulated cells, respectively (P < 0.05). On the other hand, JDT significantly increased the LPS or PHA-induced TGF-beta1 production (P < 0.05). These data suggest that JDT has a regulatory effect on the cytokines production, which might explain its beneficial effect in the treatment of CI.     

Reactivation of Epstein-Barr virus in Sj?gren''s syndrome

Summary Sjögren's syndrome (SS) is a chronic autoimmune disease characterized by severe dryness of the eyes and mouth, resulting from lymphocytic infiltration of the lacrimal and salivary glands. SS may exist as a primary condition (primary SS, 1° SS) or as a secondary condition (2° SS) in association with rheumatoid arthritis, systemic lupus erythematosus, or progressive systemic sclerosis. In some 1° SS patients, there may be involvement of the extraglandular organs, including skin, kidney, liver, lung and nervous system. Furthermore, these patients may develop a lymphoproliferative syndrome that includes lymphadenopathy and increased risk of lymphoma. In the pathogenesis of SS, a role for Epstein-Barr virus (EBV) has been suggested because: (a) EBV is present in salivary gland epithelial cells of normal individuals and exaggerated immune responses against EBV could play a role in the destruction of salivary glands in SS; (b) SS salivary gland biopsies contain increased levels of EBV DNA in comparison to normal salivary glands, indicating viral reactivation and inability of lymphoid infiltrates to control EBV replication in SS patients; and (c) salivary gland epithelial cells in SS patients express high levels of HLA-DR antigens and may present EBV-associated antigens to immune T cells in SS patients. Therefore, SS may represent a situation in which genetically predisposed individuals (i. e., HLA-DR3-DQA4-DQB2) have a persistent but ineffectual T cell immune response against EBV at its site of latency. Among 14 non-Hodgkin's lymphomas that developed in SS patients, EBV DNA was detected in increased amounts in the tumor tissue of one patient. Characterization of this tumor DNA revealed: (a) polyclonal immunoglobulin gene rearrangements; (b) EBV DNA with an unusual restriction fragment length polymorphism pattern involving the Bam M fragment; and (c) EBV terminal repeat sequences suggestive of viral replication, similar to those reported in EBV lymphomas occurring in other immunocompromised individuals. Early recognition of this clinical problem may allow beneficial use of antiviral agents.     

Ultrastructural localization of phosphoglycerate kinase in adult<Emphasis Type="Italic"> Clonorchis sinensis</Emphasis>

Phosphoglycerate kinase (PGK) is an enzyme that produces one ATP molecule in the glycolytic pathway. Clonorchis sinensis is largely dependent on glycolysis for energy production. We performed immunoelectron microscopy on adult C. sinensis by using mouse immune serum raised against recombinant C. sinensis PGK. A high density of gold particles was found in the microvilli of the intestinal epithelium and in lamellae of the sperm duct. PGK was common in the somatic cells of intra-uterine eggs and in excreted products. It was localized with moderate intensity in muscular fibers of the subtegumental muscle layer, and in the myoepithelia of the intestine and excretory bladder. We suggest that PGK plays an essential role in C. sinensis energy production for movement via muscle contraction.