Correlates of Concurrent Khat and Tobacco Use in Yemen

Background: Habitual substance use poses public health threat. This is a growing concern in countries where one or more substances are commonly used. Many individuals in Middle Eastern and East African countries use khat (Catha edulis), a stimulant often accompanied by smoking. However, few systematic attempts have been made to characterize patterns of concurrent khat and tobacco use. Objectives: To examine correlates such as gender and patterns of khat and tobacco use in concurrent users and khat-only users. Methods: This study used a cross-sectional design with a face-to-face interview method including 151 (74 women) concurrent users of khat and tobacco and 141 (76 women) khat-only users in Yemen. Data collection was completed in 2012. Analysis of variance (ANOVA) and logistic regressions were conducted to examine gender and khat use group differences in use patterns. Results: Reported frequency and intensity of khat use were greater in men than in women. Men and women khat users used different tobacco products and beverages while using khat. Khat use was more frequent in concurrent users relative to khat-only users. Earlier age of onset of khat use was associated with greater number of cigarettes smoked during a typical khat session. Approximately 70% of concurrent users reported initiating khat use prior to tobacco use. Conclusions/Importance: The results provide support for gender differences in khat and tobacco use, differences in khat use pattern between concurrent users of khat and tobacco and khat-only users, and positive associations between khat and tobacco use.     

In vivo genotoxicity study of titanium dioxide nanoparticles using comet assay following intratracheal instillation in rats

Titanium dioxide (TiO₂) is widely used as a white pigment in paints, plastics, inks, paper, creams, cosmetics, drugs and foods. In the present study, the genotoxicity of anatase TiO₂ nanoparticles was evaluated in vivo using the comet assay after a single or repeated intratracheal instillation in rats. The nanoparticles were instilled intratracheally at a dosage of 1.0 or 5.0 mg/kg body weight (single instillation group) and 0.2 or 1.0 mg/kg body weight once a week for 5 weeks (repeated instillation group) into male Sprague–Dawley rats. A positive control, ethyl methanesulfonate (EMS) at 500 mg/kg, was administered orally 3 h prior to dissection. Histopathologically, macrophages and neutrophils were detected in the alveolus of the lung in the 1.0 and 5.0 mg/kg TiO₂ groups. In the comet assay, there was no increase in % tail DNA in any of the TiO₂ groups. In the EMS group, there was a significant increase in % tail DNA compared with the negative control group. TiO₂ nanoparticles in the anatase crystal phase are not genotoxic following intratracheal instillation in rats.     

Cardiotoxic local anesthetics increasingly interact with biomimetic membranes under ischemia-like acidic conditions

The cardiotoxic effects of local anesthetics increase in cardiac ischemia which is characterized by the tissue pH lowering to 6.5 or less. Apart from the cardiac channel blockade, the membrane interaction has been referred to as another mode of their cardiotoxic action. By using biomimetic membranes, we verified the hypothesis that bupivacaine and lidocaine may increasingly interact with cardiac mitochondrial membranes under ischemia-like acidic conditions. Biomimetic membranes were prepared with different phospholipids and cholesterol to be unilamellar vesicles suspended in buffers of pH 7.4, 6.9, 6.4 or 5.9. Bupivacaine and lidocaine were reacted with the membrane preparations at cardiotoxically relevant concentrations and their membrane interactivities were determined by measuring fluorescence polarization. Both drugs interacted with 100 mol% 1,2-dipalmitoylphosphatidylcholine, peripheral nerve cell-mimetic and cardiomyocyte-mimetic membranes to increase membrane fluidity, although lowering the reaction pH from 7.4 to 5.9 decreased their membrane-fluidizing effects. In cardiomyocyte mitochondria-mimetic membranes containing 20 mol% cardiolipin, however, bupivacaine and lidocaine reversely increased their membrane interactivities at pH 5.9-6.4 compared with pH 7.4. Such increases were greater in anionic phospholipid membranes which consisted of substantial amounts of cardiolipin and phosphatidylserine. Positively charged bupivacaine and lidocaine would form ion-pairs with the negatively charged head-groups of anionic phospholipids under acidic conditions, thereby increasing the induced membrane fluidization. The mitochondrial membrane interactions depending on pH lowering may be, at least in part, responsible for local anesthetic cardiotoxicity enhanced in acidosis associated with cardiac ischemia.     

Roles of Na<Superscript>+</Superscript>/Ca<Superscript>2+</Superscript> exchanger isoforms NCX1 and NCX2 in motility in mouse ileum

The Na⁺/Ca²⁺ exchanger (NCX) is a plasma membrane transporter that is involved in regulating intracellular Ca²⁺ concentrations in various tissues. The physiological roles by which NCX influences gastrointestinal motility are incompletely understood, although its role in the heart, brain, and kidney has been widely investigated. In this study, we focused on the functions of the NCX isoforms, NCX1 and NCX2, in the motility of the ileum in the gastrointestinal tract. We investigated the response to electric field stimulation (EFS) in the longitudinal smooth muscle of the ileum obtained from wild-type mice (WT), NCX1-heterozygote knockout mice (NCX1 HET), NCX2 HET and smooth muscle-specific NCX1.3 transgenic mice (NCX1.3 Tg). EFS induced a phasic contraction that persisted during EFS and a tonic contraction that occurred after the end of EFS. We found that the amplitudes of the phasic and tonic contractions were significantly smaller in NCX2 HET, but not in NCX1 HET, compared to WT. Moreover, the magnitudes of acetylcholine (ACh)- and substance P (SP)-induced contractions of NCX2 HET, but not of NCX1 HET, were smaller compared to WT. In contrast, the amplitudes of the phasic and tonic contractions were greater in NCX1.3 Tg compared to WT. Similar to EFS, the magnitude of ACh-induced contraction was greater in NCX1.3 Tg than in WT. Taken together, our findings indicated that NCX1 and NCX2 play important roles in ileal motility and suggest that NCX1 and NCX2 regulate the motility in the ileum by controlling the sensitivity of smooth muscles to ACh and SP.     

Simultaneous changes in high-fat and high-cholesterol diet-induced steatohepatitis and severe fibrosis and those underlying molecular mechanisms in novel SHRSP5/Dmcr rat

Objectives

The aim of this study was to identify the molecular mechanisms underlying high-fat and high-cholesterol (HFC) diet-induced steatohepatitis and associated liver fibrosis progression in a novel stroke-prone, spontaneously hypertensive 5/Dmcr (SHRSP5/Dmcr) rat model.

Methods

SHRSP5/Dmcr rats were given the control or HFC-diet for 2, 8, and 16 weeks. Plasma and hepatic gene expression of key molecules involved in fatty acid oxidation, inflammation, oxidative stress, and fibrosis were subsequently analyzed.

Results

Rats fed the HFC-diet showed increased plasma tumor necrosis factor-α (TNF-α) and hepatic p50/p65 signals, but reduced hepatic Cu²⁺/Zn²⁺-superoxide dismutase across the treatment period and reduced plasma total adiponectin at 8 weeks. In HFC-diet-fed rats, transforming growth factor-β1 (TGF-β1) was elevated prior to the appearance of obvious liver fibrosis pathology at 2 weeks, followed by elevations in platelet-derived growth factor-B (PDGF-B) and α-smooth muscle actin (α-SMA), corresponding to evident liver fibrosis, at 8 weeks and by α₁ type I collagen production at 16 weeks. The HFC-diet increased hepatic total cholesterol accumulation, although hepatic triglyceride declined by 0.3-fold from 2 to 16 weeks due to reduced hepatic triglyceride synthesis, as suggested by the diacylglycerol acyltransferase 1 and 2 measurements.

Conclusions

TNF-α and p50/p65 molecular signals appeared to be major factors for HFC-diet-induced hepatic inflammation and oxidative stress facilitating liver disease progression. While the up-regulation of TGF-β1 prior to the appearance of any evident liver fibrosis could be an early signal for progressive liver fibrosis, elevated PDGF-B and α-SMA levels signified evident liver fibrosis at 8 weeks, and subsequent increased α₁ type I collagen production and reduced triglyceride synthesis indicated extensive liver fibrosis at 16 weeks in this novel SHRSP5/Dmcr model.

Electronic supplementary material

The online version of this article (doi:10.1007/s12199-012-0273-y) contains supplementary material, which is available to authorized users.     

Generation of a recombinant Oka varicella vaccine expressing mumps virus hemagglutinin-neuraminidase protein as a polyvalent live vaccine

We constructed a recombinant varicella-zoster virus (VZV) Oka vaccine strain (vOka) that contained the mumps virus (MuV) hemagglutinin-neuraminidase (HN) gene, inserted into the site of the ORF 13 gene by using the bacterial artificial chromosome (BAC) system in Escherichia coli. Insertion of the HN gene into the VZV genome was confirmed by PCR and Southern blot. The infectious virus reconstituted from the vOka-HN genome (rvOka-HN) had a growth curve similar to the original recombinant vOka without the HN gene. The mumps virus HN protein expressed in rvOka-HN infected cells was expressed diffusely in the cytoplasm, and modification of the protein was similar to that seen in MuV-infected cells. Electron microscopic examination of infected cells revealed that HN was expressed on the plasma membrane of the cells but not in the viral envelope, suggesting that the tropism of rvOka-HN would be unchanged from that of the original vOka strain. Immunization of guinea pigs with rvOka-HN-induced VZV- and HN-specific antibodies. Interestingly, the induced antibodies had a strong neutralizing activity against virus-cell infections of both MuV and VZV. Therefore, the novel varicella vaccine expressing MuV HN protein is suitable as a polyvalent live attenuated vaccine against VZV and MuV infections.     

8-Hydroxydeoxyguanosine levels in human leukocyte and urine according to exposure to organophosphorus pesticides and paraoxonase 1 genotype

Objective In order to investigate a role of paraoxonase 1 (PON1) polymorphism in organophosphorus (OP)-induced 8-hydroxydeoxyguanosine (8-OHdG) levels, urinary metabolites of OP, PON1 genotypes, and 8-OHdG levels in leukocyte and urine were measured in OP indoor insecticide sprayers and controls in summer and winter. Methods The study population contained 18 male sprayers and age-matched 18 male controls. Sprayers were primarily exposed to OP insecticides (mainly fenitrothion, dichlorvos, chlorpyrifos, and diazinon), and partially to pyrethroids (mainly permethrin) and carbamates (mainly propoxur). Urinary metabolites of OP were measured by gas chromatography-mass spectrometry. 8-OHdG levels in leukocyte and urine were measured by ELISA kit. PON1 genotype was identified using allele-specific fluorogenic TaqMan probes. Results The mean concentrations of urinary dimethyl phosphate (DMP) and total dialkyl phosphates (DAP) in summer and those of 8-OHdG in summer and winter were significantly higher in OP sprayers than controls. This resulted in a significant positive correlation between 8-OHdG levels and urinary DMP or DAP, suggesting a correlation between OP metabolites and production of oxidative stress. Of PON1 genotypes, incidences of Q/Q, Q/R, and R/R types were 17, 39, and 44% in OP sprayers and controls, respectively. Although PON1 polymorphism did not contribute to the leukocyte and urinary 8-OHdG levels, the urinary OP metabolite concentrations in summer showed a significant decrease as the number Q allele decreased. Conclusion These results indicate that an increase in OP metabolites is associated with a high level of oxidative stress in OP sprayers, although the contribution of the PON1 polymorphism to the metabolism of OP is still unclear.     

Development of WT1 peptide cancer vaccine against hematopoietic malignancies and solid cancers

Wild-type Wilms' tumor gene WT1 is highly expressed not only in hematopoietic malignancies, including leukemia and myelodysplastic syndromes (MDS), but also in various kinds of solid tumors. Human cytotoxic T lymphocytes (CTLs) which could specifically lyse WT1-expressing tumor cells with HLA class I restriction were generated in vitro. We have also demonstrated that mice immunized with the WT1 peptide or WT1 cDNA rejected challenges by WT1-expressing tumor cells and survived with no signs of auto-aggression to normal organs which physiologically expressed WT1 in prophylactic and therapeutic models. Furthermore, we and others detected IgM and IgG WT1 antibodies in the patients with hematopoietic malignancies, indicating that WT1 protein was highly immunogenic, and that immunoglobulin class-switch-inducing WT1-specific cellular immune responses were elicited in the patients. CD8+ WT1-specific CTLs were also detected in peripheral blood or tumor-draining lymph nodes of cancer patients. These results provided us with the rationale for elicitation of CTL responses targeting the WT1 product for cancer immunotherapy. On the basis of the findings mentioned above, we performed a phase I clinical trial of WT1 peptide cancer vaccine for the patients with malignant neoplasms. These results strongly suggested that WT1 peptide cancer vaccine had efficacy in the clinical setting, because clinical responses, including reduction of leukemic blast cells or regression of tumor masses, were observed after the WT1 vaccination in patients with hematopoietic malignancies or solid cancers. The power of TAA-derived cancer vaccine may be enhanced by combination with stronger adjuvants, helper peptide, or conventional treatments such as molecular-target-based drugs.