Effect of NPC15199 on [Ca²âº]i and viability in SCM1 human gastric cancer cells.

NPC15199 is a synthesized compound that inhibits inflammation in some models. However, whether NPC15199 affects Ca²âº homeostasis in human gastric cancer is unclear. This study examined the effect of NPC15199 on cytosolic free Ca²âº concentrations ([Ca²âº]i) and viability in SCM1 human gastric cancer cells. The Ca²âº-sensitive fluorescent dye fura-2 was used to measure [Ca²âº]i. NPC15199 evoked [Ca²âº]i rises concentration-dependently. The response was reduced by removing extracellular Ca²âº. NPC15199-evoked Ca²âº entry was not inhibited by store-operated channel inhibitors (nifedipine, econazole and SKF96365) and protein kinase C (PKC) activator (phorbol 12-myristate 13 acetate, PMA), or PKC inhibitor (GF109203X). In Ca²âº-free medium, treatment with the endoplasmic reticulum Ca²âº pump inhibitor thapsigargin or 2,5-di-tert-butylhydroquinone (BHQ) nearly abolished NPC15199-evoked [Ca²âº]i rises. Conversely, treatment with NPC15199 also nearly abolished thapsigargin or BHQ-evoked [Ca²âº]i rises. Inhibition of phospholipase C (PLC) with U73122 did not affect NPC15199-evoked [Ca²âº]i rises. NPC15199 at concentrations of 100-900 µM induced concentration-dependent, Ca²âº-independent decrease in viability. Together, in SCM1 cells, NPC15199 induced [Ca²âº]i rises that involved Ca²âº entry through PKC-insensitive non-store-operated Ca²âº channels and PLC-independent Ca²âº release from the endoplasmic reticulum. NPC15199 also induced Ca²âº-independent cell death.

Population structure and demographic history of Sicyopterus japonicus (Perciformes; Gobiidae) in Taiwan inferred from mitochondrial control region sequences.

The amphidromous goby Sicyopterus japonicus is distributed throughout southern Taiwan and Japan. Larvae of this freshwater fish go through a long marine stage. This migratory mode influences population genetic structure. We examined the genetic diversity, population differentiation, and demographic history of S. japonicus based on the mitochondrial DNA control region. We identified 102 haplotypes from 107 S. japonicus individuals from 22 populations collected from Taiwan and Islet Lanyu. High mean haplotype diversity (h = 0.999) versus low nucleotide diversity (θπ = 0.008) was detected across populations. There was low correspondence between clusters identified in the neighbor-joining tree and geographical region, as also indicated by AMOVA and pairwise F(ST) estimates. Both mismatch distribution analysis and Tajima's D test indicated that S. japonicus likely experienced a demographic expansion. Using a Bayesian skyline plot approach, we estimated the time of onset of the expansion of S. japonicus at 135 kyr (during the Pleistocene) and the time of stable effective population size at approximately 2.5 kyr (last glacial maximum). Based on these results, we suggest 1) a panmictic population at the oceanic planktonic larval stage, mediated by the Kuroshio current; 2) a long planktonic marine stage and long period of dispersal, which may have permitted efficient tracking of environmental shifts during the Pleistocene; and 3) a stable, constant population size ever since the last glacial maximum.

Transient renewal of thymopoiesis in HIV-infected human thymic implants following antiviral therapy.

Stem cell gene therapy strategies for AIDS require that differentiation-inducing stromal elements of HIV-infected individuals remain functionally intact to support the maturation of exogenous progenitor cells into mature CD4+ cells. To investigate the feasibility of stem cell reconstitution strategies in AIDS, we used the SCID-hu mouse to examine the ability of HIV-infected CD4+ cell-depleted human thymic implants to support renewed thymopoiesis. Here we report that following treatment of these implants with antiretroviral drugs, new thymopoiesis is initiated. This suggests that antiviral therapies might allow de novo production of T lymphocytes and provides support for the concept of therapeutic strategies aimed at reconstitution of the peripheral CD4+ T-cell compartment.

Maternal HIV-1 viral load and vertical transmission of infection: the Ariel Project for the prevention of HIV transmission from mother to infant.

Most HIV-1 infections of children result from mother-to-infant transmission, which may occur perinatally or postnatally, as a consequence of breast feeding. In this study, the influence of maternal viral load on transmission of infection to infants from non-breast-feeding mothers was examined using samples of plasma and peripheral blood mononuclear cells (PBMCs) collected at several time points during pregnancy and the 6-month period after delivery. These samples were analyzed by several quantitative methods, including virus cultures of PBMCs and polymerase chain reaction (PCR) assays for HIV-1 RNA in plasma and DNA in PBMCs. The risk of transmission increased slightly with a higher viral load, but transmission and nontransmission occurred over the entire range of values for each assay. No threshold value of virus load was identified which discriminated between transmitters and nontransmitters. We also noted a significant rise in viral load and a decline in CD4+ lymphocytes in the six months after delivery. These findings suggest that a high maternal viral load is insufficient to fully explain vertical transmission of HIV-1. Additional studies are needed to examine the post-partum increase in viremia.

In vitro activities of doripenem and other carbapenems against clinically important bacteria isolated in intensive care units: nationwide data from the SMART Programme.

This nationwide surveillance of clinically important bacteria from the intensive care units (ICUs) of major teaching hospitals throughout Taiwan investigated the susceptibilities to doripenem and other comparator carbapenems from September through November 2005. Minimum inhibitory concentrations (MICs) were determined for 1,311 clinical isolates using the broth microdilution method according to Clinical and Laboratory Standards Institute (CLSI) 2005 guidelines. Doripenem showed similar (within four-fold difference of MICs) in vitro activity to meropenem for Enterobacteriaceae and probably comparable activity to meropenem against important nosocomial non-fermentative Gram-negative bacilli (NFGNBs), including Pseudomonas aeruginosa, Acinetobacter baumannii and Burkholderia cepacia. Among the four carbapenems analysed, doripenem and meropenem exhibited better in vitro activity than imipenem or ertapenem against extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae and Escherichia coli isolates. However, the meropenem MIC(90) against ESBL-producing K. pneumoniae isolates was 2 microg/ml. Besides, doripenem with the MIC(90) of 0.5 microg/ml to Streptococcus pneumoniae possibly suggested its potential therapeutic effect regarding community-acquired pneumonia. Because of the heavy resistance burden in Taiwan, closely monitoring the evolutionary trend of carbapenem susceptibilities against clinically important pathogens is crucial in the future.

Laparoscopic preperitoneal repair for primary falciform ligament herniation.

Epigastric hernia involving the falciform ligament is exceptionally rare. Most reported cases are incisional hernia secondary to prior abdominal surgery. We report a case of primary falciform ligament herniation into the epigastric region repaired by the laparoscopic preperitoneal approach. In this case, an accompanying vessel along the herniated falciform ligament was identified. This finding provides a basis for the hypothesis of a perforating vessel piercing the linea alba and thereby creating a weak point for hernia protrusion (Moschowitz theory). The patient had an uneventful recovery and was discharged home on the postoperative day two. A laparoscopic preperitoneal approach is feasible for the repair of primary falciform ligament herniation. The magnified endoscopic view enables surgeons to achieve definite repair without missing occult defects.

HIV-1 production from infected peripheral blood T cells after HTLV-I induced mitogenic stimulation.

The human immunodeficiency virus type 1 (HIV-1) and human T-cell leukemia virus type I (HTLV-I) are two distinct human retroviruses that infect T cells. Recent epidemiologic studies have identified a cohort of individuals that are coinfected with both viruses. It is reported here that human peripheral blood leukocytes infected with HIV-1 in vitro can be induced to produce large quantities of HIV-1 after mitogenic stimulation by noninfectious HTLV-I virions. It is also shown that HTLV-I virions may exert this effect prior to, immediately following, or well after the cells are infected with HIV-1. These results provide further impetus for epidemiologic studies of dually infected individuals to determine whether HTLV-I may act as a cofactor for acquired immunodeficiency syndrome (AIDS).

Expression of the 3' terminal region of human T-cell leukemia viruses.

Human T-cell leukemia viruses (HTLV) are closely associated with some human T-cell leukemias and lymphomas. A unique 3' region of the HTLV genome is believed to be involved in HTLV-induced cellular transformation, although the function of this region has yet to be determined. A subgenomic messenger RNA transcribed from this region of HTLV has now been characterized. These results provide direct evidence for the expression of a novel gene in HTLV.

Identification of the putative transforming protein of the human T-cell leukemia viruses HTLV-I and HTLV-II.

The human T-cell leukemia viruses HTLV-I and HTLV-II are unique among the transforming retroviruses of vertebrates in their ability to transform human T cells in vitro and in their close association with human malignancies (T-cell lymphomas and leukemia). Their genomes are relatively simple, containing the genes gag, pol, env, and a 3' region termed "X." This 3' region may be responsible for the transforming potential of the viruses. The existence of proteins encoded by the 3' region has been postulated on the basis of multiple open reading frames. In the present study this region is shown to contain a gene encoding a protein of 40 kilodaltons in HTLV-I and 37 kilodaltons in HTLV-II. It is proposed that these proteins be called, respectively, p40xI and p37xII.

Cell cycle arrest by Vpr in HIV-1 virions and insensitivity to antiretroviral agents.

Expression of human immunodeficiency virus-type 1 (HIV-1) Vpr after productive infection of T cells induces cell cycle arrest in the G2 phase of the cell cycle. In the absence of de novo expression, HIV-1 Vpr packaged into virions still induced cell cycle arrest. Naturally noninfectious virus or virus rendered defective for infection by reverse transcriptase or protease inhibitors were capable of inducing Vpr-mediated cell cycle arrest. These results suggest a model whereby both infectious and noninfectious virions in vivo, such as those surrounding follicular dendritic cells, participate in immune suppression.

Functional relation between HTLV-II x and adenovirus E1A proteins in transcriptional activation.

The mechanism of cellular transformation by the human T-cell leukemia viruses (HTLV) is thought to involve a novel gene known as the x gene. This gene is essential for HTLV replication and acts by enhancing transcription from the HTLV long terminal repeat. The HTLV x gene product may also cause aberrant transcription of normal cellular genes, resulting in transformation of the infected cells. Although there is no evidence as yet for such a mechanism, it was shown that the HTLV-II x gene product can activate transcription from adenovirus E1A-dependent early promoters and therefore has the potential to activate cellular genes. It was also shown that the adenovirus and herpes pseudorabies immediate early proteins activate expression from the HTLV-I and HTLV-II long terminal repeats, though at lower levels than with the x gene product. These findings indicate possible common mechanisms of action for transcription-regulatory genes of distinct viruses.

Dual infection of the central nervous system by AIDS viruses with distinct cellular tropisms.

Human immunodeficiency virus (HIV) is the causative agent of the acquired immune deficiency syndrome (AIDS). A large number of AIDS patients show evidence of neurologic involvement, known as AIDS-related subacute encephalopathy, which has been correlated with the presence of HIV in the brain. In this study, two genetically distinct but related viruses were isolated from one patient from two different sources in the central nervous system: brain tissue and cerebrospinal fluid. Both viruses were found to replicate in peripheral blood lymphocytes, but only virus from brain tissue will efficiently infect macrophage/monocytes. The viruses also differ in their ability to infect a brain glioma explant culture. This infection of the brain-derived cells in vitro is generally nonproductive, and appears to be some form of persistent or latent infection. These results indicate that genetic variation of HIV in vivo may result in altered cell tropisms and possibly implicate strains of HIV with glial cell tropism in the pathogenesis of some neurologic disorders of AIDS.

Cytokines alter production of HIV-1 from primary mononuclear phagocytes.

Some strains of human immunodeficiency virus type 1 (HIV-1) can infect primary monocytes and monocyte-derived macrophages in vitro. In this report, the effect of cytokines on the production of one of these strains that shows a tropism for mononuclear phagocytes, designated HIV-1JR-FL, was studied. Primary peripheral blood mononuclear phagocytes infected with HIV-1JR-FL were treated with the hematopoietic factors: granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), macrophage colony-stimulating factor (M-CSF), and gamma-interferon (gamma-IFN). The M-CSF, GM-CSF, IL-3, and gamma-IFN were able to alter HIV-1 production under different conditions.

HTLV x gene mutants exhibit novel transcriptional regulatory phenotypes.

The human T-cell leukemia viruses, HTLV-I and HTLV-II, contain a gene, termed x, with transcriptional regulatory function. The properties of the x proteins were analyzed by constructing mutant genes containing site-directed deletions and point mutations. The results demonstrate that the amino terminal 17 amino acids of the x protein constitute part of a functional domain that is critical for the transcriptional activating properties of the protein. Within this region, substitution of a leucine residue for a proline residue results in major changes in the trans-activation phenotype of the protein. The mutant HTLV-II x protein, though incapable of activating the HTLV-II long terminal repeat, will block trans-activation of the HTLV-II long terminal repeat by the wild-type protein. The altered phenotype of this mutant suggests a potential negative regulatory function of the x protein.

U3 sequences from HTLV-I and -II LTRs confer pX protein response to a murine leukemia virus LTR.

Human T-cell leukemia virus (HTLV) types I and II are unusual among replication-competent retroviruses in that they contain a fourth gene (chi) necessary for replication. The chi gene product, p chi, transcriptionally transactivates the viral long repeat (LTR), and is thus a positive regulator. To investigate p chi transactivation, sequences from the U3 regions of the LTRs of HTLV-I and -II were inserted into the Moloney murine leukemia virus (M-MuLV) LTR by recombinant DNA techniques. Transient expression assays of the chimeric LTRs indicated that the HTLV sequences conferred to the M-MuLV LTR responsiveness to HTLV p chi protein. M-MuLV enhancers were not required for function of the chimeric LTRs. Infectious recombinant M-MuLVs containing chimeric LTRs were also generated. These viruses showed higher infectivity when assayed in mouse cells expressing HTLV-II p chi protein compared to normal mouse cells. Thus the HTLV sequences were able to confer p chi responsiveness to infectious M-MuLV. The generation of a virus dependent on a transactivating protein for its replication has implications for the evolution of the human T-cell leukemia viruses.

High rate of HTLV-II infection in seropositive i.v. drug abusers in New Orleans.

Confirmed infection with HTLV-II (human T cell leukemia virus type II) has been described only in rare cases. The major limitation to serological diagnosis of HTLV-II has been the difficulty of distinguishing HTLV-II from HTLV-I (human T cell leukemia virus type I) infection, because of substantial cross-reactivity between the viruses. A sensitive modification of the polymerase chain reaction method was used to provide unambiguous molecular evidence that a significant proportion of intravenous drug abusers are infected with HTLV, and the majority of these individuals are infected with HTLV-II rather than HTLV-I. Of 23 individuals confirmed by polymerase chain reaction analysis to be infected with HTLV, 21 were identified to be infected with HTLV-II, and 2 were infected with HTLV-I. Molecular identification of an HTLV-II--infected population provides an opportunity to investigate the pathogenicity of HTLV-II in humans.

HTLV x-gene product: requirement for the env methionine initiation codon.

The human T-cell leukemia viruses (HTLV) are replication-competent retroviruses whose genomes contain gag, pol, and env genes as well as a fourth gene, termed x, which is believed to be the transforming gene of HTLV. The product of the x gene is now shown to be encoded by a 2.1-kilobase messenger RNA derived by splicing of at least two introns. By means of S1 nuclease mapping of this RNA and nucleic acid sequence analysis of a complementary DNA clone, the complete primary structure of the x-gene product has been determined. It is encoded by sequences containing the env initiation codon and one nucleotide of the next codon spliced to the major open reading frame of the HTLV-I and HTLV-II x gene.

The x gene is essential for HTLV replication.

The human T-cell leukemia viruses (HTLV) are associated with T-cell malignancies in man and will transform normal human T cells in vitro. The mechanism of malignant transformation by HTLV is unknown but appears to be distinct from that of other classes of retroviruses, which induce malignant transformation through viral or cellular oncogenes. Recently a new gene, termed x, was identified in HTLV. This gene has been hypothesized to be the transforming gene of HTLV because of its conservation within the HTLV class of retroviruses. By in vitro mutagenesis of the HTLV-II x gene, it is now demonstrated that the presence of a functional x gene product is necessary for efficient HTLV transcription. Therefore, these studies provide direct evidence for an important function of the x gene in HTLV replication. The functional analogies between the x gene and transcriptional regulatory genes of some DNA viruses suggest that these viruses share similar mechanisms for cellular transformation.

HTLV-II transactivation is regulated by the overlapping tax/rex nonstructural genes.

The human T-cell leukemia virus (HTLV) types I and II have two nonstructural genes that are encoded in overlapping reading frames. One of these genes, known as tax, has been shown to encode a protein responsible for enhanced transcription (transactivation) from the viral long terminal repeats (LTRs). Genetic evidence indicates that the second nonstructural gene of HTLV-II, here designated rex, acts in trans to modulate tax gene-mediated transactivation in a concentration-dependent fashion. The rex gene may regulate the process of transactivation during the viral life cycle.