[Zinc induces normoxic accumulation of transcriptionally active hypoxia-inducible factor 1-alpha in mammary epithelial cells].

Both zinc and the α-subunit of hypoxia-inducible factor (HIF-1α) play important roles in the remodelling of mammary gland tissues. In the present study, we examined the level and the transcriptional activity of HIF-1α in mammary cells upon zinc treatment. In MCF-7 mammary adenocarcinoma and MCF-10A mammary epithelial cell lines, the toxicity levels of zinc differ. Interestingly, both cell lines overexpress HIF-1α following zinc treatment. As it was evident from an up-regulation of its specific target gene CA9 that encodes carbonic anhydrase IX, the stabilized HIF-1α translocated to the nucleus and was transcriptionally active. Hence, we conclude that zinc causes normoxic accumulation of transcriptionally active HIF-1α by interfering with its post-translational regulation.

Immunogenicity of a truncated enterovirus 71 VP1 protein fused to a Newcastle disease virus nucleocapsid protein fragment in mice.

Enterovirus 71 (EV71) is one of the viruses that cause hand, foot and mouth disease. Its viral capsid protein 1 (VP1), which contains many neutralization epitopes, is an ideal target for vaccine development. Recently, we reported the induction of a strong immune response in rabbits to a truncated VP1 fragment (Nt-VP1t) displayed on a recombinant Newcastle disease virus (NDV) capsid protein. Protective efficacy of this vaccine, however, can only be tested in mice, since all EV71 animal models thus far were developed in mouse systems. In this study, we evaluated the type of immune responses against the protein developed by adult BALB/c mice. Nt-VP1t protein induced high levels of VP1 IgG antibody production in mice. Purified VP1 antigen stimulated activation, proliferation and differentiation of splenocytes harvested from these mice. They also produced significant levels of IFN-γ, a Th1-related cytokine. Taken together, Nt-VP1t protein is a potent immunogen in adult mice and our findings provide the data needed for testing of its protective efficacy in mouse models of EV71 infections.

Detection of apoptotic cells in Vero cell cultures inoculated with samples derived from fatal cases of Sarawak acute childhood viral infection.

Infectious agent(s) causing the fatal Sarawak acute childhood viral infection (SACVI) has not been identified. In the present study, results indicating that inocula prepared from the fatal cases of SACVI induced apoptosis in Vero cell cultures are presented. These findings suggest the possible involvement of apoptotic cellular responses in SACVI.

Outbreak of fatal childhood viral infection in Sarawak, Malaysia in 1997: inocula of patients' clinical specimens induce apoptosis in vitro.

Identification of the aetiologic agent(s) associated with an outbreak of fatal childhood viral infection in Sarawak, Malaysia, in mid 1997 remains elusive. It is reported here that African green monkey kidney (Vero) and human monocytic (U937) cells treated with inocula derived from clinical specimens of some of these fatal cases showed the presence of cellular genomic DNA degradation when the extracted DNA was separated by pulsed field gel electrophoresis (PFGE), oligonucleosomal DNA ladders characteristic of apoptotic cells when the infected cells' DNA was separated by agarose gel electrophoresis, and apoptotic cellular DNA fragmentation when cells were stained using terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL). These results suggest that inocula derived from the patients' clinical specimens contain factors which stimulate apoptotic cellular responses in vitro.

Antibody responses of dengue fever patients to dengue 2 (New Guinea C strain) viral proteins.

The present study was undertaken to investigate the antibody responses of dengue fever (DF) patients to specific dengue virus proteins. Partially purified dengue 2 New Guinea C (NGC) strain virus was used as antigen. Under the present experimental protocols, it was observed that almost all DF patients' sera had detectable presence of antibodies which recognize the dengue 2 envelope (E) protein. The convalescent-phase sera especially had significant detectable IgG, IgM and IgE against the protein. In addition, IgGs specific against the NS1 dimer and PrM were also detected. Antibody against the core (C) protein, however, was not detectable in any of the DF patients' sera. The substantial presence of IgG against the PrM in the convalescent-phase sera, and the presence of IgE specific for the E, reflect the potential importance of these antibody responses in the pathogenesis of dengue.

Effect of trazodone and nefazodone on hepatic injury induced by carbon tetrachloride.

The present study aimed to evaluate the effect of the serotonin antagonists and reuptake inhibitors trazodone and nefazodone on liver injury induced by treatment with carbon tetrachloride (CCl(4)) in rats. Liver damage was induced in rats by oral administration of CCl(4) (2.8 mL/kg in olive oil). Nefazodone (5, 10, or 20 mg/kg), trazodone (5, 10, or 20 mg/kg), silymarin (25 mg/kg), or saline (control) was orally administered once daily in association with CCl(4) and for one week thereafter. Liver damage was assessed by determining serum enzyme activities and hepatic histopathology. In CCl(4)-treated rats, treatment with trazodone (5, 10, 20 mg/ kg), reduced serum alanine aminotransferase (ALT) levels by 24, 38.6, and 49.3%. Serum aspartate aminotransferase (AST) levels were decreased by 18.1, 37.9, and 42.2%, and alkaline phosphatase (ALP) levels decreased by 25.7, 32.6, and 39.7%, respectively. Nefazodone (5, 10, 20 mg/kg) in a dose-dependent manner reduced the elevation of ALT levels by 15.6, 36.5, and 45.9%, AST levels by 16.7, 17.3, and 43%, and ALP by 30.5, 37.5, and 42.9%, respectively. Silymarin treatment reduced the levels of ALT, AST, and ALP by 56.1-62.8, 56.0-64.0, and 50.1-58.2%, respectively. The administration of CCl(4) decreased levels of reduced glutathione in blood compared to the vehicle-treated group. In CCl(4)-treated rats, reduced glutathione levels increased after trazodone in a dose-dependent manner. Reduced glutathione was increased by nefazodone at concentrations of 5 and 10 mg/kg, but not after 20 mg/kg nefazodone. Reduced glutathione levels were increased by the administration of silymarin to near normal values. The administration of CCl(4) resulted in a marked increase in nitric oxide levels in serum (the concentrations of nitrite/nitrate) as compared to the control group. Treatment with trazodone or nefazodone caused a dose-dependent decrease in serum nitric oxide levels compared with the CCl(4) control group. Histopathological and histomorphometric examinations also indicated that CCl(4)-induced liver injury was less severe in trazodone and nefazodone-treated groups than in the CCl(4) control groups. Metabolic perturbations caused by CCl(4) in the form of decreased intracellular protein and mucopolysaccharide content in hepatocytes were improved by treatment with trazodone and nefazodone. It is concluded that administration of serotonin antagonists and reuptake inhibitors trazodone and nefazodone is associated with a reduction in experimental liver injury induced by CCl(4).

Molecular detection of enteroviruses from an outbreak of hand, foot and mouth disease in Malaysia in 1997.

Enterovirus 5'UTR sequences were detected by RT-PCR in 22 out of 47 suspected hand, foot and mouth disease (HFMD) patients during an outbreak of the disease with incidences of fatal brainstem encephalomyelitis in Malaysia in 1997. Genetic and phylogenetic analyses of the isolates 5'UTR sequences suggest the presence of predominantly enteroviruses with high sequence similarities to Echovirus 1 and Coxsackievirus A9 in the Malaysian peninsula. No fatal cases, however, were associated with these isolates. The remaining isolates, including all (4/4) isolates of the fatal cases from the Malaysian peninsula and Sarawak shared very high sequence identity with enterovirus 71MS (EV71). These findings suggest that several enteroviruses were circulating in Malaysia during the outbreak period, with only EV71 causing fatal infections.