WW domain-containing oxidoreductase: a candidate tumor suppressor

Common fragile site gene WWOX encodes a candidate tumor suppressor WW domain-containing oxidoreductase. Alteration of this gene, along with dramatic downregulation of WWOX protein, is shown in the majority of invasive cancer cells. Ectopic WWOX exhibits proapoptotic and tumor inhibitory functions in vitro and in vivo, probably interacting with growth regulatory proteins p53, p73 and others. Hyaluronidases regulate WWOX expression, increase cancer invasiveness and seem to be involved in the development of hormone-independent growth of invasive cancer cells. Estrogen and androgen stimulate phosphorylation and nuclear translocation of WWOX, although binding of WWOX to these sex hormones is unknown. We propose that suppression of WWOX expression by overexpressed hyaluronidases might contribute in part to the development of hormone independence in invasive cancer.

MCP-1, a highly expressed chemokine in dengue haemorrhagic fever/dengue shock syndrome patients, may cause permeability change, possibly through reduced tight junctions of vascular endothelium cells

Vascular leakage, one hallmark of dengue haemorrhagic fever (DHF) and dengue shock syndrome, has been linked to the mediators secreted from cells in the circulatory system. In this study, extremely high expression levels of monocyte chemoattractant protein-1 (MCP-1) were found in the plasma of DHF patients compared with low MCP-1 expression levels in the plasma of enterovirus 71-infected patients. It was also found that MCP-1 expression was induced in dengue virus 2 (DV2)-infected monocytes and lymphocytes, but not in liver or endothelial cells. Exposing monolayers of human umbilical vein endothelial cells (HUVECs) to recombinant human MCP-1 (rhMCP-1) or to the culture supernatant of DV2-infected human monocytes increased the vascular permeability of the cells. MCP-1-neutralizing monoclonal antibody only partially prevented monolayer permeability change. Consistently, the distribution of the tight junction protein ZO-1 on the cellular membranes of HUVECs was disrupted by rhMCP-1 or by the conditioned medium of DV2-infected monocytes. In summary, it was found that the increased permeability and disrupted tight junctions of human vascular endothelium cells were effected through a mechanism partially dependent on MCP-1, which was secreted by DV2-infected monocytes and lymphocytes.

Ceramide in apoptotic signaling and anticancer therapy

Ceramide, a product of sphingolipid metabolism, is generated in response to various stress stimuli, such as tumor necrosis factor-alpha, CD95/Fas, chemotherapeutic agents, and irradiation. Ceramide may modulate the biochemical and cellular processes that lead to apoptosis. However, the mechanisms by which ceramide regulates apoptotic events are not fully defined. It is believed that the biological effect of ceramide depends on its concentration, the activation or differentiation status of the cell, and the time frame of action. Here, we discuss the metabolism and cell apoptotic signaling of ceramide. The involvement of protein kinases (i.e. PI3K/Akt and GSK-3beta) and protein phosphatases (i.e. PP1 and PP2A), Bcl-2 family proteins, mitochondrial damage, and caspase cascade activation are demonstrated. Further, ceramide and its derivatives have recently been incorporated into strategies for anticancer therapies. An understanding of the apoptotic signaling pathways mediated by ceramide may shed light on its potential for therapeutic intervention.

Cytokines and serotonin transporter in patients with major depression

Altered cytokine secretion as a mechanism in the etiology of depression is still obscure. The serotonin transporter (5-HTT) may play an important role in the termination of serotonergic neurotransmission by serotonin (5-HT) uptaking into presynaptic neurons and representing as an initial action site for selective 5-HTT reuptake inhibitors (SSRI). In our study, we evaluated whether cytokines and 5-HTT acted as biological markers for depression. Blood samples were collected from 42 participants. The differences in cytokine and 5-HTT mRNA expressions of leukocytes were assessed between the patients with major depression (n=20) and the healthy controls (n=22), along with the measurements prior and after treatment with a SSRI, fluoxetine, for 3 months in the follow-up patient group (n=8). The results revealed that the mRNA expressions of IL-1beta, IL-6, IFNgamma, TNFalpha, and 5-HTT were higher in the depressed patients than those of the healthy controls. The higher level of mRNA expressions of IFNgamma and 5-HTT diminished after fluoxetine treatment. Furthermore, we found a positive correlation between 5-HTT and cytokines mRNA expressions in total participants, which suggested that pro-inflammatory cytokines and 5-HTT might play critical roles in the pathogenesis of major depression and that their levels were affected by chronic treatment with 5-HTT inhibitors.

Autoimmune Pathogenesis in Dengue Virus Infection

The pathogenic mechanisms of dengue hemorrhagic fever and dengue shock syndrome (DHF/DSS) caused by dengue virus (DV) infection remain unresolved. Patients with DHF/DSS are characterized by several manifestations, including severe thrombocytopenia, vascular leakage, and hepatomegaly. In addition to the effect of virus load and virus variation, abnormal immune responses of the host after DV infection may also account for the progression of DHF/DSS. Actually, viral autoimmunity is involved in the pathogenesis of numerous viral infections, such as human immunodeficiency virus, human hepatitis C virus, human cytomegalovirus, herpes simplex virus, Epstein- Barr virus, and DV. In this review, we discuss the implications of autoimmunity in dengue pathogenesis. Antibodies directed against DV nonstructural protein 1 (NS1) showed cross-reactivity with human platelets and endothelial cells, which lead to platelet and endothelial cell damage and inflammatory activation. Based on these findings, we hypothesize that anti-DV NS1 is involved in the pathogenesis of DF and DHF/DSS, and this may provide important information in dengue vaccine development.

Lithium inhibits ceramide- and etoposide-induced protein phosphatase 2A methylation, Bcl-2 dephosphorylation, caspase-2 activation, and apoptosis

Lithium confers cell protection against stress and toxic stimuli. Although lithium inhibits a number of enzymes, the antiapoptotic mechanisms of lithium remain unresolved. Here, we report a novel role of lithium on the blockage of ceramide- and etoposide-induced apoptosis via inhibition of protein phosphatase 2A (PP2A) activity. Overexpression of PP2A resulted in caspase-2 activation, mitochondrial damage, and cell apoptosis that were inhibited by okadaic acid (OA) and lithium. Lithium and OA abrogated ceramide- and etoposide-induced Bcl-2 dephosphorylation at serine 70. Furthermore, ceramide- and etoposide-induced PP2A activation involved methylation of PP2A C subunit, which lithium suppressed. Lithium caused dissociation of PP2A B subunit from the PP2A core enzyme, whereas ceramide caused recruitment of the B subunit. Taken together, lithium exhibited an antiapoptotic effect by inhibiting Bcl-2 dephosphorylation and caspase-2 activation, which involved, at least in part, a mechanism of down-regulating PP2A methylation and PP2A activity.

Volume replacement in infants with dengue hemorrhagic fever/dengue shock syndrome

Volume replacement was studied prospectively in 208 infants with dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS). The mean volume of intravenous fluid used was 110.4 mL/kg administered over a mean period of 25.8 hours. The mean volumes of intravenous fluid replacement in infants with DSS was significantly higher than in those with non-shock DHF (129.8 mL/kg versus 102.1 mL/kg; P = 0.001). Patients with DSS had significantly higher proportional requirements for dextran and blood transfusions than non-shock infants. Recurrent shock, prolonged shock, and acute respiratory failure were recorded in 8, 6, and 13 patients, respectively. Four patients with DSS died of severe complications. Intravenous fluid replacement with special care to avoid fluid overload requires careful attention to established indications for use of colloidal solutions and blood transfusions. To improve case fatality rates, special efforts need to be directed to infants with DHF/DSS accompanied by severe complications.

The Dual-Specific Binding of Dengue Virus and Target Cells for the Antibody-Dependent Enhancement of Dengue Virus Infection

Using flow cytometric assay and monoclonal anti-dengue Ab, we observed that both anti-E and anti-prM Abs could enhance dengue virus infection in a concentration-dependent but serotype-independent manner. Increases were found in both the percentage of dengue-infected cells and the expression of dengue E and NS1 protein per cell. Dengue virion binding and infection were enhanced on FcR-bearing cells via the Fc-FcgammaRII pathway. Furthermore, anti-prM Ab also enhanced dengue virion binding and infection on cells lacking FcR, such as BHK-21 or A549 cells, by the mechanism of peptide (CPFLKQNEPEDIDCW)-specific binding. Anti-prM Ab cross-reacted with BHK-21 or A549 cells and recognized self-Ags such as heat shock protein 60. In summary, a novel mechanism of anti-prM Ab-mediated enhancement on dengue virus infection was found to be mediated by dual specific binding to dengue virion and to target cells, in addition to the traditional enhancement on FcR-bearing cells.

Correlation of serum levels of macrophage migration inhibitory factor with disease severity and clinical outcome in dengue patients

Dengue virus infection can cause mild dengue fever (DF) or severe dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Cytokines are believed to be involved in the pathogenesis of dengue infection. However, the role of the pro-inflammatory cytokine macrophage migration inhibitory factor (MIF) in dengue infection is unclear. In this study, serum levels of MIF in adult dengue patients with different disease severity and clinical outcome were determined and compared with the levels of other cytokines, tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), IL-10, and interferon gamma (IFN-gamma), in the same patients. Serum levels of MIF, IL-6, and IL-10, but not IFN-gamma or TNF-alpha, were higher in all DHF patients who died than in DHF survivors and DF patients. We conclude that in addition to IL-6 and IL-10, elevated levels of serum MIF are a potential predictor of disease severity and clinical outcome in dengue patients.

Streptococcal pyrogenic exotoxin B cleaves properdin and inhibits complement-mediated opsonophagocytosis

Streptococcal pyrogenic exotoxin B (SPE B), a cysteine protease, is an important virulence factor in group A streptococcal (GAS) infection. The reduction of phagocytic activity by SPE B may help prevent bacteria from being ingested. In this study, we investigated the mechanism SPE B uses to enable bacteria to resist opsonophagocytosis. Using Western blotting and an affinity column immobilized with SPE B, we found that both SPE B and C192S, an SPE B mutant lacking protease activity, bound to serum properdin, and that SPE B, but not C192S, degraded serum properdin. Further study showed that SPE B-treated, but not C192S-treated, serum blocked the alternative complement pathway. Reconstitution of properdin into SPE B-treated serum unblocked the alternative pathway. GAS opsonized with SPE B-treated serum was more resistant to neutrophil killing than GAS opsonized with C192S-treated or normal serum. These results suggest that a novel SPE B mechanism, one which degrades serum properdin, enables GAS to resist opsonophagocytosis.

Air samples versus biomarkers for epidemiology

BACKGROUND

It has been speculated on theoretical grounds that biomarkers are superior surrogates for chemical exposures to air samples in epidemiology studies.

METHODS AND RESULTS

Biomarkers were classified according to their position in the exposure-disease continuum-that is, parent compound, reactive intermediate, stable metabolite, macromolecular adduct, or measure of cellular damage. Because airborne exposures and these different biomarkers are time series that vary within and between persons in a population, they are all prone to measurement error effects when used as surrogates for true chemical exposures. It was shown that the attenuation bias in the estimated slope characterising a log exposure-log disease relation should decrease as the within- to between-person variance ratio of a given set of air or biomarker measurements decreases. To gauge the magnitudes of these variance ratios, a database of 12,077 repeated observations was constructed from 127 datasets, including air and biological measurements from either occupational or environmental settings. The within- and between-person variance components (in log scale, after controlling for fixed effects of time) and the corresponding variance ratios for each set of air and biomarker measurements were estimated. It was shown that estimated variance ratios of biomarkers decreased in the order short term (residence time < or =2 days) > intermediate term (2 days < residence time < or =2 months) > long term biomarkers (residence time >2 months). Overall, biomarkers had smaller variance ratios than air measurements, particularly in environmental settings. This suggests that a typical biomarker would provide a less biasing surrogate for exposure than would a typical air measurement.

CONCLUSION

Epidemiologists are encouraged to consider the magnitudes of variance ratios, along with other factors related to practicality and cost, in choosing among candidate surrogate measures of exposure.

Antibody to severe acute respiratory syndrome (SARS)-associated coronavirus spike protein domain 2 cross-reacts with lung epithelial cells and causes cytotoxicity

Both viral effect and immune-mediated mechanism are involved in the pathogenesis of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) infection. In this study, we showed that in SARS patient sera there were autoantibodies (autoAbs) that reacted with A549 cells, the type-2 pneumocytes, and that these autoAbs were mainly IgG. The autoAbs were detectable 20 days after fever onset. Tests of non-SARS-pneumonia patients did not show the same autoAb production as in SARS patients. After sera IgG bound to A549 cells, cytotoxicity was induced. Cell cytotoxicity and the anti-epithelial cell IgG level were positively correlated. Preabsorption and binding assays indicated the existence of cross-reactive epitopes on SARS-CoV spike protein domain 2 (S2). Furthermore, treatment of A549 cells with anti-S2 Abs and IFN-gamma resulted in an increase in the adherence of human peripheral blood mononuclear cells to these epithelial cells. Taken together, we have demonstrated that the anti-S2 Abs in SARS patient sera cause cytotoxic injury as well as enhance immune cell adhesion to epithelial cells. The onset of autoimmune responses in SARS-CoV infection may be implicated in SARS pathogenesis.

Suckling mice were used to detect infectious dengue-2 viruses by intracerebral injection of the full-length RNA transcript

OBJECTIVE

In this study we established a mouse brain injection system to detect infectious dengue-2 virus produced from the full-length RNA transcripts.

METHODS

In vitro transcription was used to synthesize full-length dengue-2 virus RNA from the plasmid pRS424FLDEN2NGC, which was intracerebrally injected into the 6-day-old suckling mice (ICR strains). Engineered dengue-2 viruses were detected in the brain sections using immunohistochemistry staining. RT-PCR followed by restriction endonuclease BstEII digestion was used to confirm the mosquito C6/36 cells cocultured with the mouse brain extract.

RESULTS

The mice inoculated with the full-length dengue-2 viral RNA transcript showed paralysis symptoms and died between day 10 and 13 postinjection. The dengue-2 virus-specific antigens (E, Core and NS1) were detected in all the brain and part of the liver sections of the paralyzed mice by immunohistochemistry staining, indicating the existence of dengue-2 virus in these tissues of the suckling mice. The viruses detected in the brains of suckling mice were indeed infectious, which was further confirmed by coculturing mosquito C6/36 cells with the brain extract of the injected mice.

CONCLUSIONS

We developed an in vivo approach to detect and produce engineered dengue viruses with infectivity from the full-length plasmid cDNA. This suckling mice system will also aid in screening the infectious viruses that are created by site-directed mutagenesis and is useful for the studies of dengue virus gene function and pathogenesis in the host.

Cordyceps sinensis mycelium protects mice from group A streptococcal infection

Group A streptococcus (GAS) infection can cause severe invasive diseases, including necrotizing fasciitis and streptococcal toxic shock syndrome. Cordyceps sinensis, a Chinese herbal medicine, is an immunomodulator. In this study the air-pouch bacterial inoculation model was used to investigate the protective efficacy of C. sinensis mycelium extract against GAS infection. Force-feeding mice with C. sinensis mycelium extract for 3 consecutive days before GAS infection increased the survival rate and reduced local skin-tissue injury compared with mice fed PBS. Bacterial numbers in the air pouch exudates from C. sinensis-treated mice were lower than those from PBS-treated mice. Blood and organs in PBS-treated mice showed bacterial dissemination, but those in C. sinensis-treated mice did not. Three days of pretreatment with C. sinensis extract followed by C. sinensis treatment every other day after GAS infection resulted in 100% survival. The post-GAS-infection levels of aspartate aminotransferase, alanine aminotransferase and blood urea nitrogen in the sera of C. sinensis-treated mice were lower than those of PBS-treated mice. Taken together, these results show that C. sinensis mycelium extract protects by decreasing bacterial growth and dissemination, thereby increasing mouse survival rate. IL-12 and IFN-gamma expression and macrophage phagocytic activity also increased after C. sinensis treatment.

Streptococcal pyrogenic exotoxin B causes mitochondria damage to polymorphonuclear cells preventing phagocytosis of group A streptococcus

The streptococcal pyrogenic exotoxin B (SpeB) is known to be involved in group A streptococcus (GAS) survival in blood, but the detailed mechanism is not clear. For clarification of this issue, speB isogenic mutants of strains M6 and M49 were constructed by using an integrational plasmid and confirmed by Southern blot analysis. The resistance to phagocytosis of wild-type strains and their speB isogenic mutants was analyzed. The results demonstrated a five-fold increase in phagocytosis of speB mutants compared to that of wild-type strains in whole blood, but no significant difference in plasma. To further clarify whether this effect is due to a functional SpeB protein, recombinant SpeB (r-SpeB) and a SpeB mutant protein lacking proteinase activity (r-C192S) were purified and incubated with a speB mutant in whole blood. The results showed a two- to threefold increase in resistance to phagocytosis when the M6 speB mutant was incubated with r-SpeB, but not with r-C192S. Incubation with the wild-type strain, speB mutant, or the r-SpeB protein did not affect the total cell number of polymorphonuclear (PMN) cells in whole blood under laboratory conditions. However, the PMN cells' mitochondria showed decreasing dehydrogenase activity and loss of membrane potential after r-SpeB treatment. These data indicate that SpeB could cause the mitochondria damage to the PMN cells, preventing immune clearance at an early infectious stage.

Effects of oligopeptide permease in group a streptococcal infection

The oligopeptide permease (Opp) of group A streptococci (GAS) is a membrane-associated protein and belongs to the ATP-binding cassette transporter family. It is encoded by a polycistronic operon containing oppA, oppB, oppC, oppD, and oppF. The biological function of these genes in GAS is poorly understood. In order to understand more about the effects of Opp on GAS virulence factors, an oppA isogenic mutant was constructed by using an integrative plasmid to disrupt the opp operon and confirmed by Southern blot hybridization. No transcript was detected in the oppA isogenic mutant by Northern blot analysis and reverse transcriptase PCR. The growth curve for the oppA isogenic mutant was similar to that for wild-type strain A-20. The oppA isogenic mutant not only decreased the transcription of speB, speX, and rofA but also increased the transcription of speF, sagA (streptolysin S-associated gene A), slo (streptolysin O), pel (pleotrophic effect locus), and dppA (dipeptide permease). No effects on the transcription of emm, sda, speJ, speG, rgg, and csrR were found. The phenotypes of the oppA mutant were restored by the oppA revertant and by the complementation strain. The oppA mutant caused less mortality and tissue damage than the wild-type strain when inoculated into BALB/c mice via an air pouch. Based on these data, we suggest that the opp operon plays an important role in the pathogenesis of GAS infection.

Bcl-2 rescues ceramide- and etoposide-induced mitochondrial apoptosis through blockage of caspase-2 activation

Recent studies indicate that caspase-2 is involved in the early stage of apoptosis before mitochondrial damage. Although the activation of caspase-2 has been shown to occur in a large protein complex, the mechanisms of caspase-2 activation remain unclear. Here we report a regulatory role of Bcl-2 on caspase-2 upstream of mitochondria. Stress stimuli, including ceramide and etoposide, caused caspase-2 activation, mitochondrial damage followed by downstream caspase-9 and -3 activation, and cell apoptosis in human lung epithelial cell line A549. When A549 cells were pretreated with the caspase-2 inhibitor benzyloxycarbonyl-Val-Asp(-OMe)-Val-Ala-Asp(-OMe)-fluoromethyl ketone or transfected with caspase-2 short interfering RNA, both ceramide- and etoposide-induced mitochondrial damage and apoptosis were blocked. Overexpression of Bcl-2 prevented ceramide- and etoposide-induced caspase-2 activation and mitochondrial apoptosis. Furthermore, caspase-2 was activated when A549 cells were introduced with Bcl-2 short interfering RNA or were treated with Bcl-2 inhibitor, which provided direct evidence of a negative regulatory effect of Bcl-2 on caspase-2. Cell survival was observed when caspase-2 was inhibited in Bcl-2-silencing cells. Blockage of the mitochondrial permeability transition pore and caspase-9 demonstrated that Bcl-2-modulated caspase-2 activity occurred upstream of mitochondria. Further studies showed that Bcl-2 was dephosphorylated at serine 70 after ceramide and etoposide treatment. A protein phosphatase inhibitor, okadaic acid, rescued Bcl-2 dephosphorylation and blocked caspase-2 activation, mitochondrial damage, and cell death. Taken together, ceramide and etoposide induced mitochondria-mediated apoptosis by initiating caspase-2 activation, which was, at least in part, regulated by Bcl-2.

Cloning and characterization of a small-size peptide Zfra that regulates the cytotoxic function of tumor necrosis factor by interacting with JNK1

By cDNA library screening, here we isolated an unusual gene transcript encoding a 31-amino-acid zinc finger-like peptide that regulates apoptosis (named Zfra). Northern blotting and RT/PCR showed the transcript is abundant in spleen but absent in several prostate and breast cancer cells. When stably expressed in L929 fibroblasts, Zfra conferred resistance to the cytotoxic effects of TNF and FasL. In contrast, transiently expressed Zfra could enhance or inhibit the cytotoxicity of overexpressed death domain proteins TRADD, FADD, and RIP of the TNF signaling pathway. By GST pull-down assay and co-immunoprecipitation, TNF and UV light were shown to induce Zfra to rapidly self-associate and bind JNK1. While JNK1 is a downstream effector of the TNF signaling, Zfra regulation of the TNF cytotoxic function is likely due to its interaction, in part, with JNK1.

Sentinel node detection with radiocolloid lymphatic mapping in early invasive cervical cancer

We assessed the feasibility of sentinel lymph node detection using technicium-99 radiocolloid lymphatic mapping for predicting lymph node metastases in early invasive cervical cancer. Thirty patients with cervical cancer (stages IA2-IIA) underwent preoperative lymphoscintigraphy using technicium-99 intracervical injection and intraoperative lymphatic mapping with a handheld gamma probe. After dissection of the sentinel nodes, the standard procedure of pelvic lymph node dissection and radical hysterectomy was performed as usual. The sentinel node detection rate was 100% (30/30). There were seven (23.3%) cases of microscopic lymph node metastases on pathologic analysis. All of them had sentinel node involvement. Therefore, the sensitivity of sentinel node identification for prediction of lymph node metastases was 100%, and no false negative was found. Preoperative lymphoscintigraphy, coupled with intraoperative lymphatic mapping, located the sentinel nodes accurately in our study patients. This sentinel node detection method appears to be feasible for predicting lymph node metastases.

Expression of cytokine, chemokine, and adhesion molecules during endothelial cell activation induced by antibodies against dengue virus nonstructural protein 1

Vascular dysfunction is a hallmark associated with disease onset in dengue hemorrhagic fever and dengue shock syndrome. In addition to direct viral damage, immune responses to dengue virus (DV) infection may also underlie the pathogenesis of disease. We have proposed a mechanism of molecular mimicry in which Abs directed against DV nonstructural protein 1 (NS1) cross-react with endothelial cells and induce damage. In this study, we demonstrated the inflammatory endothelial cell activation induced by anti-DV NS1 via the transcription factor NF-kappaB-regulated pathway. Protein phosphorylation and NF-kappaB activation were observed after anti-DV NS1 stimulation in a human microvascular endothelial cell line-1. The cytokine and chemokine production, including IL-6, IL-8, and MCP-1, but not RANTES, in endothelial cells increased after treatment with anti-DV NS1 Abs. The expression of IL-6, IL-8, and MCP-1 was blocked by the preabsorption of anti-DV NS1 with DV NS1 or by the inhibition of NF-kappaB activation. Furthermore, the increases in both ICAM-1 expression and the ability of human PBMC to adhere to endothelial cells were also observed, and these effects were inhibited by pretreatment with anti-ICAM-1 or anti-MCP-1 Abs. Therefore, in addition to endothelial cell apoptosis, as previously reported, inflammatory activation occurs in endothelial cells after stimulation by anti-DV NS1 Abs. These results suggest the involvement of anti-DV NS1 Abs in the vasculopathy of DV infection.

Double-clad Cr4+:YAG crystal fiber amplifier

A novel double-clad Cr4+:YAG crystal fiber is demonstrated by use of a codrawing laser-heated pedestal growth method. Up to 10 dB of gross gain at a wavelength of 1.52 microm is achieved at a pump power of 0.83 W, which, to our knowledge, is the first Cr4+-doped fiber amplifier in the optical fiber communication band.

Elevated serum levels of a c-erbB-2 oncogene product in oral squamous cell carcinoma patients

OBJECTIVES

Amplification of the proto-oncogene c-erbB-2 (HER-2/neu) has been shown to be a prognostic marker in many kinds of cancer including oral squamous cell carcinoma (OSCC). In order to obtain further information on the c-erbB-2 gene product p185, it is necessary to quantify expression levels. In this study we used an enzyme-linked immunosorbent assay (ELISA) for the extracellular domain of p185 to determine whether a soluble oncoprotein fragment can be detected in the serum of OSCC patients.

METHOD

Sera from 84 OSCC patients, 51 breast cancer patients (as positive controls), and 15 healthy controls were assayed in an ELISA. To study c-erbB-2 overexpression in OSCC, and breast cancer tissue samples we used an immunohistochemical technique.

RESULTS

The mean serum value (ng/ml, mean/SD) for the normal controls was 8.46/1.29. We chose the 95% level of normal controls as a cut-off to distinguish individuals with elevated levels. The breast cancer patients' and OSCC patients' serum values were 13.83/6.82 and 13.1/4.56, respectively. Significant differences (P < 0.0001) were observed between normal control and OSCC, normal control and the breast cancer group. Immunohistochemically detectable p185 (intermediate to high) was noted in 30 of 61 OSCC, and 24 of 51 breast cancer patients. There was a trend of association of serum oncoprotein fragment levels with tumor stages, but not with tumor sizes, nodal stages, metastases, and oral habits including betel quid chewing, alcohol drinking and smoking in the OSCC group.

CONCLUSION

The results of the present study raise the possibility that soluble c-erbB-2 protein levels in serum is a useful parameter for monitoring the disease status as well as the effect of therapy on patients with OSCC.

Streptococcal pyrogenic exotoxin B-induced apoptosis in a549 cells is mediated by a receptor- and mitochondrion-dependent pathway

It has been shown that streptococcal pyrogenic exotoxin B (SPE B) can induce cells to undergo apoptosis. The present study is to dissect the role of SPE B protease and SPE B protein in the apoptotic process of A549 cells and to elucidate the SPE B-induced apoptotic pathway. Recombinant SPE B (rSPE B) and C192S, a mutant of SPE B without protease activity, were expressed in Escherichia coli and purified by using an affinity column. The apoptosis of A549 cells was assayed by propidium iodide staining, followed by flow cytometry analysis. Our results showed that SPE B induced apoptosis in a dose-dependent manner, whereas C192S did not. When cells were pretreated with rSPE B (2 mug/ml) for as briefly as 5 min and then incubated with C192S of 28 kDa, an apoptosis that is proportional to the period of pretreatment was observed but not with C192S of 42 kDa. These results suggest that the extracellular protease activity of rSPE B is required for the initiation of apoptosis and that the size of SPE B is important for an effective induction of apoptosis. The time course analysis revealed that molecules activated in apoptosis were in the following order: caspase-8 (1.5 h), t-Bid (2.5 h), Bax (3 h), cytochrome c release (6 h), caspase-9 (7 h), and caspase-3 (8 h). The overexpression of Bcl-2 inhibited depolarization of mitochondrial membrane, cytochrome c release, and apoptosis. The results of the present study suggest that SPE B-induced apoptosis is mediated through a receptor-like mechanism and a mitochondrion-dependent pathway.

On the Importance of Exposure Variability to the Doses of Volatile Organic Compounds

The connection between occupational exposure to volatile organic compounds (VOCs) and the resulting internal doses is complicated by variability in air levels from day to day and by nonlinear kinetics of metabolism. We investigated long-term liver doses of VOCs and their metabolites using a physiologically based toxicokinetic model, to which 10,000 random 8-h exposures were inputted. Three carcinogenic VOCs were studied (i.e., benzene, perchloroethylene, and acrylonitrile); these compounds are all bioactivated in the liver and represent a wide range of an important toxicokinetic parameter Vmax/QL x KM. For each VOC, simulations were performed using mean air concentrations (muX) between 0.0003 and 1 mg/l (which covers both linear and saturated metabolism) and using coefficients of variation of exposure (CVX) between 0.23 and 2.18 (which includes most occupational settings). Two long-term measures of internal dose were examined, i.e., the area under the liver concentration-time curve (AUCL) and the area under the metabolic rate-time curve (AURC). Interestingly, both AUCL and AURC were linear functions of cumulative exposure (CE, mg x h/l air) even when metabolism was saturated and CVX was large. Yet, at a given CE, both AUCL and AURC were affected by CVX, with the magnitude of the effect increasing with Vmax/QL x KM (i.e., perchloroethylene < benzene < acrylonitrile). Nonetheless, the effects of CVX were typically only a few percent and should be of little consequence unless a VOC has large values of Vmax/QL x KM, muX,and CVX. We conclude that CE should be a sufficient predictor of the dose of either the parent chemical (VOC) or its metabolite in the liver, even when metabolism is nonlinear. We also observed that AUCL and AURC were sensitive to changes in values of model parameters in the high-variability scenarios, suggesting that (when CVX is large) the population variability of AUCL and AURC can be quite large at a fixed CE.

Molecular sieving MFI-type zeolite membranes for pervaporation separation of xylene isomers

Molecular sieving MFI-type zeolite membranes were prepared by a secondary growth method without using an organic template. Silicalite membranes with intercrystalline pores minimized or eliminated were obtained by this synthesis method which avoids the template removal step. The silicalite membrane exhibits molecular sieving characteristics with pervaporation separation factor for p-xylene to o-xylene or m-xylene of as high as about 70, the highest ever reported for a pervaporation membrane.

Sequential caspase-2 and caspase-8 activation upstream of mitochondria during ceramideand etoposide-induced apoptosis

Recently, caspase-2 was shown to act upstream of mitochondria in stress-induced apoptosis. Activation of caspase-8, a key event in death receptor-mediated apoptosis, also has been demonstrated in death receptor-independent apoptosis. The regulation of these initiator caspases, which trigger the mitochondrial apoptotic pathway, is unclear. Here we report a potential regulatory role of caspase-2 on caspase-8 during ceramide-induced apoptosis. Our results demonstrate the sequential events of initiator caspase-2 and caspase-8 activation, Bid cleavage and translocation, and mitochondrial damage followed by downstream caspase-9 and -3 activation and cell apoptosis after ceramide induction in T cell lines. The expression of truncated Bid (tBid) and the reduction in mitochondrial transmembrane potential were blocked by caspase-2 or caspase-8, but not caspase-3, knockdown using an RNA interference technique. Ceramide-induced caspase-8 activation, mitochondrial damage, and apoptosis were blocked in caspase-2 short interfering RNA-expressing cells. Therefore, caspase-2 acts upstream of caspase-8 during ceramide-induced mitochondrial apoptosis. Similarly, sequential caspase-2 and caspase-8 activation upstream of mitochondria was also observed in etoposide-induced apoptosis. These data suggest sequential initiator caspase-2 and caspase-8 activation in the mitochondrial apoptotic pathway induced by ceramide or etoposide.

Histopathologic changes in kidney and liver correlate with streptococcal pyrogenic exotoxin B production in the mouse model of group A streptococcal infection

Previous studies show that isogenic mutants deficient in streptococcal pyrogenic exotoxin B (SPE B) cause less mortality and skin tissue damage than wild-type strains of Streptococcus pyogenes when inoculated into mice via an air pouch. In this study, the growth and dissemination of bacteria, pathologic changes in various organs, and their correlation with SPE B production were examined. Bacterial numbers in the air pouch from wild-type strain NZ131-infected mice increased at 48 h, while those from speB mutant SW510-infected mice continuously reduced. Mice infected with NZ131 developed bacteremia and greater dissemination in the kidney, liver, and spleen; those infected with SW510 showed either no or slight bacteremia and dissemination. Co-inoculation of SW510 with recombinant SPE B showed a higher bacterial count in the air pouch, bacteremia, and organ dissemination compared to co-inoculation with a C192S mutant lacking protease activity. The histopathologic changes examined showed lesions in kidney and liver in the NZ131-infected but not in SW510-infected mice. The elevation in sera of BUN, AST, and ALT correlated positively with renal and liver impairment. Taken together, SPE B produced during S. pyogenes infection plays a pathogenic role. A direct effect of SPE B on vessel permeability change was also demonstrated.

Antibody-mediated endothelial cell damage via nitric oxide

Vascular disorders, resulting from endothelial cell dysfunction, may be caused by various stimuli, including infectious pathogens, cytotoxic reagents, and pathophysiological mechanisms mediated by immune responses. Endothelial cell dysfunction characterized by apoptosis and abnormal immune activation is, at least in part, induced by anti-endothelial cell antibody (AECA) in some cases of autoimmune disease. However, the molecular mechanisms of AECA-mediated pathogenetic damage to host vascular system remain unclear. The dual role of nitric oxide (NO) both in endothelial cell apoptosis and survival has been described. In this paper, endothelial cell apoptosis caused by the presence of cross-reactive AECA via a NO-mediated mechanism is demonstrated in dengue virus infection. Endothelial cells undergo apoptosis via the mitochondria-dependent pathway that is regulated by NO production. NO-regulated endothelial cell injury thus may play a role in the disruption of vessel endothelium and contribute to the AECA-induced pathogenesis of vasculopathy. The modulation of NO may provide the therapeutic strategies for autoimmune diseases by preventing the AECA-mediated endothelial cell damage.

Molecular analysis of group A streptococcal isolates associated with scarlet fever in southern Taiwan between 1993 and 2002

Collected between 1993 and 2002 at a Taiwanese university hospital, 77 group A streptococcus isolates associated with scarlet fever were grouped by emm typing and pulsed-field gel electrophoresis. The predominance of an emm1 clone before 1996 and the presence of genetically diverse emm1 and emm4 strains thereafter were found.

Dengue hemorrhagic fever in infants: a study of clinical and cytokine profiles

A prospective study of clinical and cytokine profiles of 107 infants with dengue hemorrhagic fever (DHF)/dengue shock syndrome (DSS) was conducted. Fever, petechiae on the skin, and hepatomegaly were the most common clinical findings associated with DHF/DSS in infants. DSS occurred in 20.5% of the patients. Hemoconcentration and thrombocytopenia were observed in 91.5% and 92.5% of the patients, respectively. Serologic testing revealed that almost all of the patients (95.3%) had primary dengue virus infections. These data demonstrate that clinical and laboratory findings of DHF/DSS in infants are compatible with the World Health Organization's clinical diagnostic criteria for pediatric DHF. The present study is the first to report evidence of production of cytokines in infants with DHF/DSS and to describe the difference between the cytokine profile of infants with primary dengue virus infections and children with secondary infections. Overproduction of both proinflammatory cytokines (interferon-gamma and tumor necrosis factor-alpha) and anti-inflammatory cytokines (interleukin-10 and -6) may play a role in the pathogenesis of DHF/DSS in infants.

Down-regulation of Bcl-2, activation of caspases, and involvement of reactive oxygen species in 6-hydroxydopamine-induced thymocyte apoptosis

OBJECTIVE

Our previous work showed that 6-hydroxydopamine (6-OHDA) induced mouse thymocytes to undergo apoptosis both in vivo and in vitro. In the present study, we further investigated the mechanisms of 6-OHDA-induced apoptosis in vitro.

METHODS

Naive mouse thymocytes were cultured with 6-OHDA. The percentages of apoptotic cells were quantified by propidium iodide staining, and DNA fragmentation was detected by agarose gel electrophoresis. Intracellular Bcl-2 was analyzed by immunofluorescence staining. Cu/Zn superoxide dismutase (Cu/Zn-SOD) activities were measured by the SOD-525 method.

RESULTS

The apoptotic effect of 6-OHDA was blocked by desipramine, a catecholamine uptake blocker. Treatment with 6-OHDA caused a reduction in Bcl-2 expression. VAD-FMK, a broad-spectrum caspase inhibitor, and DEVD-CHO, a potent inhibitor of caspase-3, could block 6-OHDA-induced thymocyte apoptosis. However, the specific caspase-1 (ICE) inhibitor YVAD-CMK had no effect. This cell death process was prevented by the protein synthesis inhibitor cycloheximide and by antioxidants. The level of Cu/Zn-SOD activities also decreased after cells were exposed to 6-OHDA.

CONCLUSION

These results suggest an apoptotic effect of 6-OHDA via the uptake of this neurotoxin by thymocytes, and that down-regulation of Bcl-2, activation of caspases, such as caspase-3 but not caspase-1, generation of reactive oxygen species, and new synthesis of proteins are involved in this process.

Combined removal of SO2 and NO using sol-gel-derived copper oxide coated alumina sorbents/catalysts

The present paper reports experimental results on the removal of sulfur dioxide and nitrogen oxide from simulated flue gas using a copper oxide coated on alumina sorbent/catalyst prepared by the sol-gel method. Selective catalytic reduction of nitric oxide by ammonia over sol-gel derived CuO/gamma-Al2O3 sorbents/catalysts with different degrees of sulfation was studied in a fixed-bed packed reactor. The optimum temperature for NO reduction was found at 350 degrees C for both fresh and sulfated catalysts. The properties for simultaneous removal of SO2 and NO by the sol-gel-derived CuO/gamma-Al2O3 sorbents were studied using simulated dry flue gas. The optimum operating temperature for the combined deSO2/deNO operations was identified at 350 degrees C. At the space velocity of 5200 h(-1) and 350 degrees C, a fixed-bed reactor packed with the 7.9 wt% CuO/gamma-Al2O3 sorbent prepared by the sol-gel method offers SO2 sorption capacity of 2.3 mmol g(-1) and NO conversion of 92% with a dry simulated flue gas as the feed. Under these experimental conditions, the sol-gel derived sorbents/catalysts have comparable efficiency for removal of SO2 and NOx as their commercial counterparts. The significantly higher crush strength of the sol-gel derived sorbents/catalysts make them very promising for their use in the copper oxide process for combined removal of SO2 and NOx from flue gas in a single unit operation.

Tissue plasminogen activator induced by dengue virus infection of human endothelial cells

Dengue hemorrhagic fever and dengue shock syndrome (DHF/DSS) are severe complications of dengue virus (DV) infection. However, the pathogenesis of hemorrhage induced by dengue virus infection is poorly understood. Since endothelial cells play a pivotal role in the regulation of hemostasis, we studied the effect of DV infection on the production of tissue plasminogen activator (tPA) and plasminogen activator inhibitor 1 (PAI-1) in vitro using both primary isolated endothelial cells, human umbilical cord veins cells, and a human microvascular endothelial cell line. DV infection significantly induced the secretion of tPA but not PAI-1 of human endothelial cells. In addition, tPA mRNA of endothelial cells was induced by DV as demonstrated by RT-PCR. Antibody against IL-6 but not control antibody inhibited DV-induced tPA production of endothelial cells. Furthermore, a good correlation between sera levels of IL-6 and tPA was found in DHF but not DF patients. These results suggest that IL-6 can regulate DV-induced tPA production of endothelial cells, which may play important roles in the pathogenic development of DHF/DSS.

Maturation processing and characterization of streptopain

Streptopain is a cysteine protease expressed by Streptococcus pyogenes. To study the maturation mechanism of streptopain, wild-type and Q186N, C192S, H340R, N356D and W357A mutant proteins were expressed in Escherichia coli and purified to homogeneity. Proteolytic analyses showed that the maturation of prostreptococcal pyrogenic exotoxin B zymogen (pro-SPE B) involves eight intermediates with a combination of cis- and trans-processing. Based on the sequences of these intermediates, the substrate specificity of streptopain favors a hydrophobic residue at the P2 site. The relative autocatalytic rates of these mutants exhibited the order Q186N > W357A > N356D, C192S, H340R. Interestingly, the N356D mutant containing protease activity could not be converted into the 28-kDa form by autoprocessing. This observation suggested that Asn(356) might involve the cis-processing of the propeptide. In addition, the maturation rates of pro-SPE B with trypsin and plasmin were 10- and 60-fold slower than that with active mature streptopain. These findings indicate that active mature streptopain likely plays the most important role in the maturation of pro-SPE B under physiological conditions.

Mechanism of high-temperature CO2 sorption on lithium zirconate

Lithium zirconate (Li2ZrO3) is one of the most promising materials for CO2 separation from flue gas at high temperature. This material is known to be able to absorb a large amount of CO2 at around 400-700 degrees C. However, the mechanism of the CO2 sorption/desorption process on Li2ZrO3 is not known yet. In this study, we examined the CO2 sorption/desorption mechanism on Li2ZrO3 by analyzing the phase and microstructure change of Li2ZrO3 during the CO2 sorption/desorption process with the help of thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) analyses. Li2ZrO3 powders were prepared from lithium carbonate (Li2CO3) and zirconium oxide (ZrO2) by the solid-state method, and the CO2 sorption/desorption property was examined by TGA. It was shown that pure Li2ZrO3 absorbs a large amount of CO2 at high temperature with a slow sorption rate. Addition of potassium carbonate (K2CO3) and Li2CO3 in the Li2ZrO3 remarkably improves the CO2 sorption rate of the Li2ZrO3 materials. DSC analysis for the CO2 sorption process indicates that doped lithium/potassium carbonate is in the liquid state during the CO2 sorption process and plays an important role in improving the CO2 uptake rate. XRD analysis for phase and structure change during the sorption/desorption process shows that the reaction between Li2ZrO3 and CO2 is reversible. Considering all data obtained in this study, we proposed a double-shell model to describe the mechanism of the CO2 sorption/desorption on both pure and modified Li2ZrO3.

Cross-talk between tumor cells and neutrophils through the Fas (APO-1, CD95)/FasL system: human glioma cells enhance cell viability and stimulate cytokine production in neutrophils

Many tumor cells are resistant to Fas-mediated killing, which has been primarily used as a mechanism to evade immune attack. In this study, we found a new action of Fas on tumors where activation of the Fas signal may force tumor cells to produce survival factors for neutrophils. Human peripheral circulating neutrophils in coculture with glioma cells showed significant delays in spontaneous apoptosis. Interleukin (IL)-6 and IL-8 partially mediated the glioma cell-associated, protective effect on neutrophils. The Fas agonistic antibody CH-11 dose-dependently stimulated the expression of IL-6 and IL-8 in glioma cells. Accordingly, blocking the Fas/FasL interaction reduced IL-6 and IL-8 production in glioma cells and impaired their protective effect on neutrophils. Coculture with glioma cells also affected the expression of cytokines in neutrophils, including IL-8, interferon-gamma, and tumor necrosis factor alpha to various extents. Collectively, our results demonstrate bi-directional cross-talk between tumor and immune cells. Although Fas activation alone cannot induce apoptosis in tumor cells, it may potentially initiate an effective anti-tumor response through a circumvented mechanism.

Use of polymerase chain reaction to detect the soft rot pathogen, Pythium myriotylum, in infected ginger rhizomes

AIMS

The aims are to establish a polymerase chain reaction (PCR)-based method for detecting Pythium myriotylum in the rhizome of ginger and diagnosing ginger soft rot and screening health seed ginger.

METHODS AND RESULTS

A booster PCR method was established for detection of P. myriotylum using a specific primer selected from rDNA ITS1 region coupled with universal primer ITS2. It successfully applied to the detection of P. myriotylum in naturally infected ginger rhizomes but not from DNA of ginger rhizomes collected from field without target fungus.

CONCLUSIONS

A specific method for detecting P. myriotylum was achieved.

SIGNIFICANCE AND IMPACT OF THE STUDY

The new PCR method has allowed us to monitor ginger for the presence of P. myriotylum as a way of disease diagnosis or healthy seed ginger examination.

Antibodies from dengue patient sera cross-react with endothelial cells and induce damage

Dengue virus infection causes a wide range of diseases from the mild febrile illness dengue fever to the life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Vascular leakage and hemorrhagic syndrome are the clinical features associated with dengue infection, yet the mechanisms remain unclear. In this study, the cross-reactivity of dengue patient sera with endothelial cells was demonstrated. There were higher percentages of endothelial cells reactive with dengue hemorrhagic fever/dengue shock syndrome patient sera than those with dengue fever patient sera. The percentages of endothelial cells reactive with patient serum IgM were higher than those with IgG. Further studies showed that the endothelial cell binding activity was inhibited by pretreatment with dengue virus nonstructural protein 1 (NS1). The antibodies against NS1 produced after dengue virus infection may, at least in part, account for the cross-reactivity of patient sera with endothelial cells. Furthermore, dengue patient sera induced endothelial cell apoptosis via a caspase-dependent pathway that was also inhibited by NS1 pretreatment. In addition to apoptosis, patient sera caused cell lysis in the presence of complement, and DHF/DSS patient sera showed higher percentages of cytotoxicity than dengue fever patient sera. Thus, the generation of cross-reactive autoantibodies against endothelial cells would lead to their dysfunction, which may play a role in the pathogenesis of dengue virus infection.

Virus replication and cytokine production in dengue virus-infected human B lymphocytes

Dengue virus (DV) replication, antibody-enhanced viral infection, and cytokine responses of human primary B lymphocytes (cells) were characterized and compared with those of monocytes. The presence of a replication template (negative-strand RNA intermediate), viral antigens including core and nonstructural proteins, and increasing amounts of virus with time postinfection indicated that DV actively replicated in B cells. Virus infection also induced B cells to produce interleukin-6 and tumor necrosis factor alpha, which have been previously implicated in virus pathogenesis. In addition, a heterologous antibody was able to enhance both virus and cytokine production in B cells. Furthermore, the levels of virus replication, antibody-enhanced virus replication, and cytokine responses observed in B cells were not statistically different from those in monocytes. These results suggest that B cells may play an important role in DV pathogenesis.

Heparin inhibits dengue-2 virus infection of five human liver cell lines

Liver is suggested to be the major target of dengue virus infection and plays an important role in the immunopathogenesis of dengue hemorrhagic fever. Previously, we reported that five human liver cell lines (HuH-7, HA22T, Hep3B, PLC, and Chang liver) with various degrees of differentiation and tumorigenicity showed different susceptibility for dengue virus infection. Here, we demonstrate that heparin, an analogue of heparan sulfate (HS), can compete with HS on cell membrane for virus binding and subsequently inhibits the replication of dengue-2 and Japanese encephalitis viruses in hepatoma and BHK-21 cells, respectively. It indicates that the binding of these viruses with HS is an important process for their invasion. Moreover, the inhibitory effect of heparin correlates with the infectivity of the virus in the cells. All together, our results suggest that HS is an important host component for dengue and Japanese encephalitis virus replication, which can be effectively blocked by heparin.

Transient CD4/CD8 ratio inversion and aberrant immune activation during dengue virus infection

The immune status after dengue virus infection was studied in dengue patients from an outbreak of serotype 3 dengue virus infection in the southern part of Taiwan during November and December 1998. Consecutive blood samples from 29 dengue patients, of whom 21 had dengue fever and 8 had dengue hemorrhagic fever/dengue shock syndrome, were collected, and the immunophenotypes of the peripheral blood mononuclear cells were determined by flow cytometry. The early activation marker CD69 appeared on lymphocytes and monocytes at day 4 after the onset of fever, and declined afterward. However, a transient reverse in the CD4/CD8 ratio occurred at days 6-10 after the onset of fever. The CD4/CD8 ratio inversion was manifested in 10 of 29 dengue patients and was encountered more frequently in dengue hemorrhagic fever/dengue shock syndrome than in dengue fever patients. Analysis of the clinical blood cell count of these 10 cases showed that increase of immature neutrophils developed at fever days 5-6, CD4(dim) or CD8(dim) monocytosis at days 6-7, and atypical lymphocytosis at days 8-10 after the onset of fever. Serum IL-6 was found at either day 7 or day 9-11. The PHA-stimulated T-cell response was depressed as well. These changes in immune parameters indicate aberrant immune activation during dengue virus infection and might be involved in the pathogenesis of dengue virus infection.

Endothelial cell apoptosis induced by antibodies against dengue virus nonstructural protein 1 via production of nitric oxide

The onset of vascular leakage and hemorrhagic diathesis is one of the life-threatening complications occurring in dengue patients, yet the pathogenic mechanisms are not well understood. In this study, we demonstrated that Abs against dengue virus nonstructural protein 1 (NS1) generated in mice cross-reacted with human endothelial cells and mouse vessel endothelium. After binding, mouse anti-NS1 Abs induced endothelial cell apoptosis in a caspase-dependent manner. Inducible NO synthase expression could be observed; it showed a time- and dose-dependent correlation with NO production. Endothelial cell apoptosis, characterized by exposure of phosphatidylserine on the cell surface and nuclear DNA fragmentation, was blocked by treatment with the NO synthase inhibitor N(omega)-nitro-L-arginine methyl ester. Further studies demonstrated that the expression of Bcl-2 and Bcl-x(L) decreased in both mRNA and protein levels, whereas p53 and Bax increased after anti-NS1 treatment. Cytochrome c release was also observed. All of these effects could be inhibited by N(omega)-nitro-L-arginine methyl ester. Taken together, anti-NS1 Abs act as autoantibodies that cross-react with noninfected endothelial cells and trigger the intracellular signaling leading to the production of NO and to apoptosis. Endothelial cell damage may cause vascular leakage that contributes to the pathogenesis of dengue disease.

The effect of dexamethasone upon patient-controlled analgesia-related nausea and vomiting

Ninety female patients were enrolled in this randomised, double-blind, placebo-controlled study to compare the anti-emetic effect of intravenous dexamethasone 8 mg with saline control in preventing patient-controlled analgesia-related nausea and vomiting following major orthopaedic surgery. The prophylactic administration of dexamethasone 8 mg significantly reduced the overall incidence of patient-controlled analgesia-related nausea and vomiting (p<0.001) and the need for rescue anti-emetics (p<0.01). Furthermore, patients who received dexamethasone showed a higher incidence of complete responses (no vomiting or need for rescue anti-emetic for a 24-h postoperative period) than those who received saline (p<0.05). We conclude that dexamethasone 8 mg may be valuable for preventing patient-controlled analgesia-related nausea and vomiting in women undergoing major orthopaedic surgery.

In-vivo phenotyping for CYP3A by a single-point determination of midazolam plasma concentration

We investigated whether a single plasma midazolam concentration could serve as an accurate predictor of total midazolam clearance, an established in-vivo probe measure of cytochrome P450 3A (CYP3A) activity. In a retrospective analysis of data from 224 healthy volunteers, non-compartmental pharmacokinetic parameters were estimated from plasma concentration-time curves following intravenous (IV) and/or oral administration. Based on statistical moment theory, the concentration at the mean residence time (MRT) should be the best predictor of the total area under the curve (AUC). Following IV or oral midazolam administration, the average MRT was found to be approximately 3.5 h, suggesting that the optimal single sampling time to predict AUC was between 3 and 4 h. Since a 4-h data point was common to all studies incorporated into this analysis, we selected this time point for further investigation. The concentrations of midazolam measured 4 h after an IV or oral dose explained 80 and 91% of the constitutive interindividual variability in midazolam AUC, respectively. The 4-h midazolam measurement was also an excellent predictor of drug-drug interactions involving CYP3A induction and inhibition. Compared with baseline values, the direction and magnitude of change in midazolam AUC and the 4-h concentration were completely concordant for all study subjects. We conclude that a single 4-h midazolam concentration following IV or oral administration represents an accurate marker of CYP3A phenotype under constitutive and modified states. Moreover, the single-point approach offers an efficient means to phenotype and identify individuals with important genetic polymorphisms that affect CYP3A activity.

Prevention of PONV with dexamethasone in female patients undergoing desflurane anesthesia for thyroidectomy

BACKGROUND

Desflurane is associated with a higher incidence of 24-h postoperative nausea and vomiting (PONV) as compared with sevoflurane or isoflurane. Dexamethasone 5 mg i.v. is suggested to be the minimum effective dose for prophylaxis of PONV in women undergoing thyroidectomy with isoflurane anesthesia. The objective of this study was to investigate whether a 5 mg dose of dexamethasone could be enough for, or a larger dose at 8 mg, could be more capable of preventing PONV in women undergoing desflurane anesthesia for thyroidectomy.

METHODS

One hundred and thirty five patients were assigned to receive one of three treatment regimens prior to induction i.e., dexamethasone 8 mg i.v. (Group D8), dexamethesone 5 mg i.v. (Group D5) or saline (Group S).

RESULTS

It was demonstrated that the prophylactic administration of either dexamethasone 8 mg or 5 mg significantly reduced the overall incidence of PONV in patients undergoing thyroidectomy with desflurane anesthesia (P < 0.001, Group D8 vs. Group S; Group D5 vs. Group S). However, patients who received dexamethasone 8 mg showed a higher incidence of complete responses (no vomiting or need of rescue antiemetic medication for a 24-h postoperative period) in comparison with those receiving dexamethasone 5 mg (86% vs. 67%; P < 0.01).

CONCLUSIONS

The results of this study showed that in PONV prophylaxis, in female patients undergoing desflurane anesthesia for thyroidectomy, the effect of dexamethasone 8 mg was superior to that of dexamethasone 5 mg.

Antiproliferative effect of nitric oxide on rat glomerular mesangial cells via inhibition of mitogen-activated protein kinase

The effect of nitric oxide (NO) donors and lipopolysaccharide (LPS) on the proliferation of rat glomerular mesangial cells was characterized. Exogenous application of a NO donor inhibited serum-induced proliferation in a time- and dose-dependent manner. S-Nitrosoglutathione (GSNO) also increased cGMP generation and arachidonic acid release, but it did not cause any measurable increase in the cytosolic Ca2+ concentration. Chelation of cytosolic Ca2+ or inhibition of mitogen-activated protein kinase (MAPK) kinase had an inhibitory effect on proliferation, but neither enhanced the antiproliferative effect of GSNO. In contrast, inhibition of guanylate cyclase or phospholipase A2 had no effect on proliferation, but partially reversed GSNO-induced antiproliferation by approximately 98 and 65%, respectively. GSNO did not cause cell death. Incubation of cells with LPS induced endogenous NO generation and had an antiproliferative effect. LPS-induced antiproliferation was reversed completely by inhibition of nitric oxide synthase and partially by inhibition of guanylate cyclase or phospholipase A2. GSNO or LPS inhibited serum-induced MAPK activation, and both effects were partially reversed by inhibition of guanylate cyclase or phospholipase A2. Inclusion of 8-bromo-cGMP or arachidonic acid in the growth medium resulted in a similar antiproliferative effect. In conclusion, in rat glomerular mesangial cells, MAPK inhibition and an antiproliferative effect could be induced by either an increase in the cellular concentration of NO or exposure of the cells to LPS. Part of the effect of NO was attributable to the increased cellular cGMP generation and arachidonic acid release.

New phenanthridine linkers for the solid-phase synthesis of acid-containing compounds

Two novel, reusable phenanthridine linkers that use cerium ammonium nitrate as a cleavage reagent are described. These linkers are based on a disubstituted amide and are designed for the release of carboxylic acids but tolerate exposure to acidic, basic, and reductive reaction conditions. Application of these linkers to solid-phase organic synthesis affords products in excellent yields and high purities.

Facile allylic C-H bond activation on the bridging disulfide ligand in the Ru(III) dinuclear complex having a conjugated RuSSRu core

Treatment of [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)(mu-S(2))](CF(3)SO(3))(4) (1), which is prepared by the reaction of [[RuCl(P(OCH(3))(3))(2)](2)(mu-S(2))(mu-Cl)(2)] (2) with 4 equiv of AgCF(3)SO(3), with terminal alkenes such as 1-pentene, allyl ethyl ether, allyl phenyl ether, 1,4-hexadiene, and 3-methyl-1-butene, resulted in the formation of complexes carrying a C(3)S(2) five-membered ring, [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCH(2)CH(2)CR(1)R(2)S]](CF(3)SO(3))(4) (3, R(1) = CH(2)CH(3), R(2) = H, 40%; 4, R(1) = OCH(2)CH(3), R(2) = H, 60%; 5, R(1) = OC(6)H(5), R(2) = H, 73%; 6, R(1) = CH=CHCH(3), R(2) = H, 48%; 7, R(1) = R(2) = CH(3), 40%). Reaction of 1 with methylenecycloalkanes was found to give several different types of products, depending on the ring size of the substrates. A trace of [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCH(CH(2)CH(2))CH(CH(3))S]](CF(3)SO(3))(4) (9) having a C(2)S(2) four-membered ring to bridge the two Ru atoms was obtained by the reaction of 1 with methylenecyclobutane, whereas the reaction with methylenecyclohexane gave [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-S(CH(2)(C=CHCH(2)CH(2)CH(2)CH(2))S)](CF(3)SO(3))(3) (10) in 69% yield via C-S bond formation and elimination of a proton. Throughout these reactions with alkenes giving a variety of products, the activation of the allylic C-H bond is always the essential and initial key step.