Characterization of novel UCP5/BMCP1 isoforms and differential regulation of UCP4 and UCP5 expression through dietary or temperature manipulation

Mitochondrial uncoupling proteins have been implicated in the maintenance of metabolic rate and adaptational thermoregulation. We recently reported the identification of a brain-specific mitochondrial uncoupling protein homologue, UCP4. Here we characterized another newly described member of the uncoupling protein family, termed UCP5 (also called BMCP1). UCP5 transcripts are present in multiple human and mouse tissues, with an especially high abundance in the brain and testis. Expression of UCP5 in mammalian cells reduces the mitochondrial membrane potential. Multiple isoforms of UCP5 were identified and exhibited tissue-specific distribution and different potency in reduction of membrane potential. Furthermore, the mRNA abundance of both UCP4 and UCP5 is modulated by nutritional status or temperature in a tissue-specific manner in mice. Brain UCP4 and UCP5 mRNA transcripts rose by 1.5- and 1.7-fold, respectively, and liver UCP5 expression increased by 1.8-fold in response to acute cold exposure. A high-fat diet increased UCP5 mRNA in liver by 1.6-fold selectively in the obesity-resistant A/J but not in the obesity-prone C57BL/6J mouse strain. Liver UCP5 expression decreased significantly with a 24 h fast and was restored to the normal level after refeeding. In contrast, brain transcripts for both genes were not significantly altered by fasting or high-fat diet. These findings are consistent with the notion that UCP4 and UCP5 may be involved in tissue-specific thermoregulation and metabolic changes associated with nutritional status.

Impact of endotoxin on UCP homolog mRNA abundance, thermoregulation, and mitochondrial proton leak kinetics

Linking tissue uncoupling protein (UCP) homolog abundance with functional metabolic outcomes and with expression of putative genetic regulators promises to better clarify UCP homolog physiological function. A murine endotoxemia model characterized by marked alterations in thermoregulation was employed to examine the association between heat production, UCP homolog expression, and mitochondrial proton leak ("uncoupling"). After intraperitoneal lipopolysaccharide (LPS, approximately 6 mg/kg) injection, colonic temperature (T(c)) in adult female C57BL6/J mice dropped to a nadir of approximately 30 degrees C by 8 h, preceded by a four- to fivefold drop in liver UCP2 and UCP5/brain mitochondrial carrier protein 1 mRNA levels, with no change in their hindlimb skeletal muscle (SKM) expression. SKM UCP3 mRNA rose fivefold during development of hypothermia and was correlated with an LPS-induced increase in plasma free fatty acid concentration. UCP2 and UCP5 transcripts recovered about three- to sixfold in both tissues starting at 6-8 h, preceding a recovery of T(c) between 16 and 24 h. SKM UCP3 followed an opposite pattern. Such results are not consistent with an important influence of UCP3 in driving heat production but do not preclude a role for UCP2 or UCP5 in this process. The transcription coactivator PGC-1 displayed a transient LPS-evoked rise (threefold) or drop (two- to fivefold) in SKM and liver expression, respectively. No differences between control and LPS-treated mouse liver or SKM in vitro mitochondrial proton leak were evident at time points corresponding to large differences in UCP homolog expression.

Aromatic DNA adducts in coke-oven workers, in relation to exposure, lifestyle and genetic polymorphism of metabolic enzymes

OBJECTIVE

This study investigates the effect of multiple factors, including exposure to polycyclic aromatic hydrocarbons (PAHs), lifestyle, genetic polymorphism of cytochrome P450 (CYP)1A1, glutathione transferase (GST)M1, GSTP1, N-acetyltransferase (NAT)2 and gene p53, as well as any family history of cancer, on DNA adduct levels in coke-oven workers.

METHODS

Sixty-five coke-oven workers employed at the largest iron-steel factory in China were recruited for the study. Personal data were collected at the interview. DNA adduct levels in total white blood cells (WBCs) were detected using 32P-postlabeling techniques. Genetic polymorphisms were analyzed by polymerase chain reaction (PCR) methods.

RESULTS

The subjects were divided into low and high exposure groups, according to personal exposure to PAHs. The mean adduct value was 1.57 (range 0.54 to 4.35) per 10(8) nucleotides. A tendency for increased levels of DNA adducts in the high exposure group was observed, compared with the low exposure group (P = 0.07). In the low exposure group, DNA adducts were found to be positively associated with urinary cotinine (r = 0.44, P = 0.01). The rare allele homozygotes of CYP1A1 showed significantly higher DNA adduct levels than those of other CYP1A1 genotypes. Individuals with the NAT2 wild type had significantly increased DNA adduct levels than those with other NAT2 genotypes in the high exposure group. The p53 genetic polymorphism revealed a significantly positive effect on DNA adducts formation. There was a significantly higher adduct level in the subjects with a family history of cancer than those without, in the high exposure category.

CONCLUSIONS

Effects of several variables, such as smoking, genetic polymorphism of 2 CYP1A1, NAT2, and gene p53, and a family history of cancer on DNA adduct levels were found, suggesting that these variables should be considered when evaluating the genotoxic effect of occupational exposure to PAHs using WBCs DNA adducts.

Increased death receptor 5 expression by chemotherapeutic agents in human gliomas causes synergistic cytotoxicity with tumor necrosis factor-related apoptosis-inducing ligand in vitro and in vivo

The intractability of malignant gliomas to multimodality treatments plays a large part in their extremely poor prognosis. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a novel member of the tumor necrosis factor (TNF) family that induces apoptosis preferentially in tumor cells through binding to its cognate death receptors, DR4 and DR5. Here we show that the DNA-damaging chemotherapeutic drugs, cis-diamminedichloroplatinum(II) (CDDP) and etoposide, elicited increased expression of DR5 in human glioma cells. Exposure of such cells in vitro to soluble human TRAIL in combination with CDDP or etoposide resulted in synergistic cell death that could be blocked by soluble TRAIL-neutralizing DR5-Fc or the caspase inhibitors, Z-Asp-CH2-DCB and CrmA. Moreover, systemic in vivo administration of TRAIL with CDDP synergistically suppressed both tumor formation and growth of established s.c. human glioblastoma xenografts in nude mice by inducing apoptosis without causing significant general toxicity. The combination treatment resulted in complete and durable remission in 29% of mice with the established s.c. xenografts and also significantly extended the survival of mice bearing intracerebral xenografts. These results provide preclinical proof-of-principle for a novel therapeutic strategy in which the death ligand, TRAIL, is safely combined with conventional DNA-damaging chemotherapy.

Allosteric inhibitors of inducible nitric oxide synthase dimerization discovered via combinatorial chemistry

Potent and selective inhibitors of inducible nitric oxide synthase (iNOS) (EC ) were identified in an encoded combinatorial chemical library that blocked human iNOS dimerization, and thereby NO production. In a cell-based iNOS assay (A-172 astrocytoma cells) the inhibitors had low-nanomolar IC(50) values and thus were >1,000-fold more potent than the substrate-based direct iNOS inhibitors 1400W and N-methyl-l-arginine. Biochemical studies confirmed that inhibitors caused accumulation of iNOS monomers in mouse macrophage RAW 264.7 cells. High affinity (K(d) approximately 3 nM) of inhibitors for isolated iNOS monomers was confirmed by using a radioligand binding assay. Inhibitors were >1,000-fold selective for iNOS versus endothelial NOS dimerization in a cell-based assay. The crystal structure of inhibitor bound to the monomeric iNOS oxygenase domain revealed inhibitor-heme coordination and substantial perturbation of the substrate binding site and the dimerization interface, indicating that this small molecule acts by allosterically disrupting protein-protein interactions at the dimer interface. These results provide a mechanism-based approach to highly selective iNOS inhibition. Inhibitors were active in vivo, with ED(50) values of <2 mg/kg in a rat model of endotoxin-induced systemic iNOS induction. Thus, this class of dimerization inhibitors has broad therapeutic potential in iNOS-mediated pathologies.

[An epidemiologic study of irritable bowel syndrome in Beijing - a stratified randomized study by clustering sampling]

OBJECTIVE

To explore the prevalence of irritable bowel syndrome (IBS) and its risk factors in Beijing.

METHODS

Phase I: a screening program for IBS was carried out in Beijing area according to symptoms using both Manning (modified including constipation) and Rome criteria. Random clustered sampling involving 2 486 subjects of the inhabitants was carried out under stratification of city, suburban and rural areas. Sample size of each studied area was in proportion to the population of the area. The range of age was 18 - 70. All subjects studied were requested to fill in a questionnaire assisted by trained doctors or medical students during the visit to their families. Phase II: a small number of patients who fulfilled the Manning criteria were further selected to undergo detail clinical examination in the hospital including laboratory examination, abdominal ultrasonography, colonoscopy or/and barium enema to exclude organic disease of the colon. Prevalence of IBS of the population was then adjusted by the rate of correct diagnosis during phase II study. Minnesota Multi - Personality Indices was used in some cases. Potential risk factors were explored by comparing frequencies among IBS group and non - IBS group using chi(2) and logistic analysis of multifactors.

RESULTS

The adjusted point prevalence of IBS in Beijing according to Manning criteria was 7.26%, in contrast to Rome criteria - 0.82%. Higher prevalence rate of IBS in the city (10.50%) than in rural areas (6.14%) (P < 0.001) was noticed. Male to female ratio was 1:1.15 with majority of IBS fell in age 18 - 40 (51.6%), and among intellectuals. Our study indicated that history of dysentery (OR = 3.00), exposure to coldness (OR = 1.55), ingestion of cold food and raw materials (OR = 1.24) might serve as the most important risk factors (P < 0.001). Patients with IBS seemed to have a higher tendency of abnormal personalities.

CONCLUSION

IBS is a common disorder in Beijing which deserves greater care.

[Distribution and transferring of carbon in kast soil system of peak forest depression in humid subtropical region]

Taking Guilin Yaji Karst Experiment Site as an exemple and with the methods of field monitoring and laboratory analysis, this paper studied the distribution and transferring of carbon in the karst soil system of peak forest depression in the humid subtropical region of China. The carbon pools in biomass, litters and soil organic matter(SOM) and their mobility as expressed by oxidizability and decomposition rate of SOM, the concentration of soil CO2 and the emission rate of CO2 from soil were investigated. The mobile carbon pool in the system supplied a rich source of CO2, which drived the karst process. When active karst process happened in Spring and Summer, over 60% of carbon in the output water was derived from soil CO2, as traced by delta 13 C distribution in the system. Therefore, owing to the carbon transfer in the pathway of air-plant-soil-water, karst process took place rather under soil-rock-water interface than under air-rock-water interface. Thus, the epigenetic karst process was driven and accelerated by soil as an interface of carbon environmental geochemistry.

Requirement of calmodulin binding by HIV-1 gp160 for enhanced FAS-mediated apoptosis

Accelerated apoptosis is one mechanism proposed for the loss of CD4+ T-lymphocytes in human immunodeficiency virus type 1 (HIV-1) infection. The HIV-1 envelope glycoprotein, gp160, contains two C-terminal calmodulin-binding domains. Expression of gp160 in Jurkat T-cells results in increased sensitivity to FAS- and ceramide-mediated apoptosis. The pro-apoptotic effect of gp160 expression is blocked by two calmodulin antagonists, tamoxifen and trifluoperazine. This enhanced apoptosis in response to FAS antibody or C(2)-ceramide is associated with activation of caspase 3, a critical mediator of apoptosis. A point mutation in the C-terminal calmodulin-binding domain of gp160 (alanine 835 to tryptophan, A835W) eliminates gp160-dependent enhanced FAS-mediated apoptosis in transiently transfected cells, as well as in vitro calmodulin binding to a peptide corresponding to the C-terminal calmodulin-binding domain of gp160. Stable Tet-off Jurkat cell lines were developed that inducibly express wild type gp160 or gp160A835W. Increasing expression of wild type gp160, but not gp160A835W, correlates with increased calmodulin levels, increased apoptosis, and caspase 3 activation in response to anti-FAS treatment. The data indicate that gp160-enhanced apoptosis is dependent upon calmodulin up-regulation, involves the activation of caspase 3, and requires calmodulin binding to the C-terminal binding domain of gp160.

Epidemiologic study of the irritable bowel syndrome in Beijing: stratified randomized study by cluster sampling

OBJECTIVE

To explore the prevalence of irritable bowel syndrome (IBS) in Beijing and its risk factors.

METHODS

Phase I: a screening for IBS in Beijing area according to symptoms using both Manning (modified including constipation) and Rome criteria. 2486 subjects were studied by cluster sampling of the inhabitant groups according to a stratified design of urban, suburban and rural areas, and sample size of each area studied was in proportion to the population of the area. Selection of the inhabitant groups was made by simple random sampling. Age of subjects enrolled in the study was 18-70 years. All subjects fulfilling the selection criteria were requested to fill in a questionnaire assisted by trained doctors or medical students during the visit to their families. Phase II: an aliquot of patients who fulfilled at least the Manning criteria were further selected according to their scoring series to undergo detail clinical examination in the hospital including laboratory examination, abdominal ultrasonography, colonoscopy or/and barium enema to exclude organic disease of the colon. Prevalence of IBS of the population was then adjusted by the rate of correct diagnosis during Phase II study. Study using Minnesota Multi-Personality Indices (MMPI) was done in some cases. Probable risk factors were explored by comparing their frequencies among IBS group and non-IBS group using chi 2 and logistic analysis of multifactors.

RESULTS

The adjusted point prevalence of IBS in Beijing is 7.26% according to Manning criteria, and is 0.82% according to Rome criteria. There is a higher prevalence rate in city (10.50%) than in rural areas (6.14%) by stratified analysis (P < 0.001). Male to female ratio is 1:1.15. And IBS is more common in people aged between 18-40 years (51.6%), and among the intellectuals. Our study indicated that history of dysentery (OR 3.00), exposure to cool (OR 1.55) and ingestion of cold food and raw materials (OR 1.24) may be the most important risk factors (P < 0.001), and IBS patients may have a higher tendency of psychological abnormalities.

CONCLUSION

IBS is a common disorder in Beijing and should be taken into consideration in the human welfare strategy.

Regional correlation between estimated UVB levels and skin cancer mortality in Japan

Most ecological studies investigating the relationship between incidence and/or mortality of skin cancer and surrogate measures of ultraviolet radiation B (UVB) have been conducted among the Caucasian population. The objective of the present study was therefore to assess the geographical correlation between ambient UVB estimates and regional mortality rates for skin cancer in Japan. The standardized mortality ratio (SMR) for malignant melanoma and other malignant neoplasms of the skin was calculated by sex, region and time-period for all deaths occurring in the period 1973-1994. The Spearman's correlation coefficient was calculated between estimated ambient UVB and regional SMRs for the two types of skin cancer. There was no geographical correlation between UVB and skin cancer mortality, except for a significantly negative correlation in malignant melanoma among males and a significantly negative correlation in other malignant neoplasms of the skin confined to unexposed anatomic sites of the body among females. The characteristic ecological relationship adds to the importance of conducting further epidemiological studies at the individual level in Japan.

[Application of IL-1 beta and 8 mRNA and some other indices in monitoring the activity of ulcerative colitis]

OBJECTIVE

To evaluate the monitoring action of the expression of IL-1 beta, IL-8 mRNA, myeloperoxidase (MPO) and superoxide dismutase (SOD) activity in the active ulcerative celitis (UC).

METHODS

Twenty active UC patients, 23 inactive UC patients; and 14 non-UC inflammation patients were selected. Twelve patients who complained of flatulence, abdominal pain and constipation receiving endoscopic examination were used as control. MPO and SOD activity, IL-1 beta and IL-8 mRNA expression (hybridization in situ) were determined on the endoscopic biopsy specimens of all patients. In 20 active UC patients, 14 patients received endoscopic examination and 4 indices detection were done once again after 2 months' treatment with prednisone and SASP.

RESULTS

Mucosal MPO activities of active UC patients, inactive UC patients, and non-UC inflammation patients are higher than those of control patients, (19.37 +/- 0.54, 11.59 +/- 1.41, and 12.97 +/- 0.49) U/g tissue vs (9.49 +/- 0.51) U/g tissue (P < 0.01). SOD activities are lower than that of control patients, (5.03 +/- 07,7. 7.66 +/- 0.79, and 6.98 +/- 0.61) U/mg protein vs (8.82 +/- 0.58) U/mg protein (P < 0.05). Mucosal MPO activity of active UC patients is also higher than that of inactive and non-UC inflammation patients (P < 0.01); while SOD activity is lower than them (P < 0.01). After 2 months' medical treatment, MPO activity of 14 active UC patients decreased, (12.61 +/- 0.74) U/g tissue vs (19.31 +/- 0.44) U/g tissue (P < 0.01), while SOD activity elevated (7.44 +/- 0.55) U/mg protein vs (5.10 +/- 1.05) U/mg protein (P < 0.05), compared with that of before treatment. Positive expression of IL-1 beta mRNA appeared in the epithelial and inflammatory cells of all active UC patients, 9 inactive UC patients, and 7 non-UC inflammation patients. While expression of IL-8 mRNA only appeared positively in all active UC patients. In 14 active UC patients, there were no detection of interleukin mRNA expression after 2 months' treatment.

CONCLUSIONS

Mucosal MPO, SOD, IL-1 beta, and IL-8 mRNA could be used as 4 indices monitoring the activity of UC. And IL-1 beta mRNA is also helpful to supervise early or late UC activity.

Knock-out of the neural death effector domain protein PEA-15 demonstrates that its expression protects astrocytes from TNFalpha-induced apoptosis

Apoptosis is a very general phenomenon, but only a few reports concern astrocytes. Indeed, astrocytes express receptors for tumor necrosis factor (TNF) alpha, a cytokine demonstrated on many cells and tissues to mediate apoptosis after recruitment of adaptor proteins containing a death effector domain (DED). PEA-15 is a DED-containing protein prominently expressed in the CNS and particularly abundant in astrocytes. This led us to investigate if PEA-15 expression could be involved in astrocytic protection against deleterious effects of TNF. In vitro assays evidence that PEA-15 may bind to DED-containing protein FADD and caspase-8 known to be apical adaptors of the TNF apoptotic signaling. After generation of PEA-15 null mutant mice, our results demonstrate that PEA-15 expression increases astrocyte survival after exposure to TNF.

Small molecule antagonists of the bradykinin B1 receptor

Screening Pharmacopeia's encoded combinatorial libraries has led to the identification of potent, selective, competitive antagonists at the bradykinin B1 receptor. Libraries were screened using a displacement assay of [3H]-des-Arglo-kallidin ([3H]-dAK) at IMR-90 cells expressing an endogenous human B1 receptor (Bmax = 20,000 receptors/cell, K(D) = 0.5+/-0.1 nM) or against membranes from 293E cells expressing a recombinant human B1 receptor (Bmax = 8,000 receptors/cell, K(D) = 0.5 +/- 0.3 nM). Compound PS020990, an optimized, representative member from the class of compounds, inhibits specific binding of 3H-dAK at IMR-90 cells with a KI of 6 +/- 1 nM. The compound inhibits dAK-induced phosphatidyl inositol turnover (K(Bapp) = 0.4 +/- 0.2 nM) and calcium mobilization (K(Bapp) = 17 +/- 2 nM) in IMR-90 cells. Compounds from the lead series are inactive at the B2 receptor and are > 1000-fold specific for B1 vs. a variety of other receptors, ion channels and enzymes. PS020990 and other related chemotypes therefore offer an excellent opportunity to explore further the role of B1 receptors in disease models and represent a potential therapeutic avenue.

Apoptosis and tumorigenesis in human cholangiocarcinoma cells. Involvement of Fas/APO-1 (CD95) and calmodulin

We have previously demonstrated that tamoxifen inhibits the growth of human cholangiocarcinoma cells in culture and inhibits tumor growth when cells are injected into nude mice. However, the mechanism of action of tamoxifen remains unknown. Here we demonstrate that tamoxifen and trifluoperazine, both potent calmodulin antagonists, induce apoptosis in vitro, probably acting via the Fas system, in human cholangiocarcinoma cells. Human cholangiocarcinoma cell lines heterogeneously express Fas antigen on their surface. Fas-negative and Fas-positive surface-expressing cells were isolated, cloned, and cultured. Fas antibody, tamoxifen, and trifluoperazine induced dose-dependent apoptosis only in Fas-positive cells; Fas-negative cells were unaffected. Furthermore, apoptosis induced by tamoxifen in Fas-positive cells was blocked by an inhibitory Fas antibody. Tamoxifen was not acting through an anti-estrogenic mechanism, because neither Fas-negative nor Fas-positive cells expressed estrogen receptors and the pure anti-estrogen compound, ICI 182780, did not induce apoptosis in either cell line. Fas-negative cells, but not Fas-positive cells, were able to produce tumors when subcutaneously injected into nude mice. These findings suggest Fas may be a candidate oncogene involved in the pathogenesis of cholangiocarcinoma. Furthermore, the similarity between the pro-apoptotic effects of tamoxifen and trifluoperazine support an underlying molecular mechanism for Fas-mediated apoptosis that involves calmodulin.

Fas expression prevents cholangiocarcinoma tumor growth

Cholangiocarcinoma continues to have a dismal prognosis with an overall survival rate of less than 10%. An increased understanding of the molecular oncogenesis of this tumor is needed. Fas/APO-1 (CD95) receptor and Fas ligand have been implicated as key factors in apoptosis. In this study we have examined the role of the Fas receptor in the growth of cholangiocarcinoma. The purpose of this study was to evaluate the role of the Fas receptor in the induction of apoptosis in cholangiocarcinoma and to assess the role of the Fas receptor in cholangiocarcinoma tumorigenesis. Human cholangiocarcinoma cells, SK-ChA-1, were evaluated for Fas receptor expression using fluorescence-activated cell sorting (FACS). Distinct cell populations (Fas-positive and Fas-negative) were isolated by FACS and cloned from single cell dilutions. Fas expression was assessed by FACS and reverse transcriptase-polymerase chain reaction (RT-PCR). Cell populations were further characterized by their sensitivity to anti-Fas monoclonal antibody at 72 hours. Cell viability and apoptotic index were evaluated by trypan blue cell count and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL) assay, respectively. Distinct cell populations were evaluated for their ability to form tumors in BALB/c nude mice (2.5 x 10(6) cells per subcutaneous injection). After 4 weeks, tumors were evaluated for tumor area by caliper measurement and Fas expression by RT-PCR. Maintenance of biliary phenotype was assured by means of AE-1 (cytokeratin) immunohistochemistry. Populations of Fas-positive and Fas-negative cells were identified, isolated, and confirmed by FACS and RT-PCR. Treatment of Fas-positive cells with anti-Fas monoclonal antibody produced an 80% reduction in cell viability compared to no decrease in viability in Fas-negative cells by trypan blue cell count. TUNEL staining showed an apoptotic index of 75% for Fas-positive cells incubated with anti-Fas monoclonal antibody and no significant evidence of apoptosis in the Fas-negative cells. When cholangiocarcinoma cells were subcutaneously injected into nude mice, only Fas-negative cells formed tumor nodules; Fas-positive cells failed to form tumor nodules. The analyzed tumors lacked Fas messenger RNA by RT-PCR but maintained the biliary cytokeratin AE-1 by immunohistochemistry. Fas receptor expression is an important mediator of apoptosis in cultured human cholangiocarcinoma cells and appears to be a critical determinant of cholangiocarcinoma tumor growth in nude mice.

TRAIL (Apo-2L) and TRAIL receptors in human placentas: implications for immune privilege

Mechanisms accounting for protection of the fetal semiallograft from maternal immune cells remain incompletely understood. In other contexts, interactions between TRAIL (TNF-related apoptosis-inducing ligand/Apo-2L) and its receptors kill activated lymphocytes. The purpose of this study was therefore to investigate the potential of the TRAIL/TRAIL-R system to protect the placenta against immune cell attack. Analysis by Northern blotting demonstrated mRNAs encoding TRAIL as well as the four TRAIL receptors (DR4, DR5, DcR1/TRID, DcR2/TRUNDD) in human placentas. Immunohistochemical experiments demonstrated that TRAIL protein is prominent in syncytiotrophoblast, an uninterrupted placental cell layer that is continuously exposed to maternal blood, as well as in macrophage-like placental mesenchymal cells (Hofbauer cells). Studies on cell lines representing trophoblasts (Jar, JEG-3 cells) and macrophages (U937, THP-1 cells) showed that both lineages contained TRAIL mRNA and that steady state levels of transcripts were increased 2- to 11-fold by IFN-gamma. By contrast, cell lineage-specific differences were observed in expression of the TRAIL-R genes. Although all four lines contained mRNA encoding the apoptosis-inducing DR5 receptor, only trophoblast cells contained mRNA encoding the DcR1 decoy receptor and only macrophages contained DcR2 decoy receptor transcripts. DR4 mRNA was present only in THP-1 cells and was the only TRAIL-R transcript increased by IFN-gamma. Cytotoxicity assays revealed that the two trophoblast cell lines were resistant, whereas the two macrophage lines were partially susceptible to killing by rTRAIL. Collectively, the results are consistent with a role for the TRAIL/TRAIL-R system in the establishment of placental immune privilege.

[Experimental studies in vitro on the alpha-fetoprotein-specific promoter mediated target gene therapy of hepatocellular carcinoma]

OBJECTIVE

To investigate the alpha-fetoprotein (AFP)-specific promoter mediated target gene therapy of hepatocellular carcinoma in vitro.

METHODS

Retroviral vector (LX2.2CD) in which the cytosine deaminase (CD) gene was driven by the 2.2 kb recombinant human AFP TRS. After transfecting three human hepatoma cell lines and one non-hepatoma cell line with LX2.2 CD, anti-G418 clones integrated CD gene were selected, and inhibitory experiment of cell growth was performed.

RESULTS

5-fluorocytosine (5FC) could confer the chemosensitivity to transduced AFP-producing hepatoma cells (HuH-7 and huH-1/c1-2), but not to AFP-nonproducing hepatoma cells (HLE) or nonhepatoma cells (GLC). On the other hand, when transfecting the above four tumor cell lines with another retroviral vector pCD2 (CD gene was driven by 5'LTR internal promoter), no cell selection was found in 5FC-induced cell grow inhibition.

CONCLUSIONS

Recombinant retrovival transfer of the CD gene under the control of the AFP TRS followed by 5FC may well be a promising trageted gene therapy for hepatoma.

[A single strand comformation polymorphism of vacuolating cytotoxin gene in H. pylori]

OBJECTIVE

To use PCR/SSCP analysis of the vacuolating cytotoxin gene (vacA) of H. pylori for differentiation of various strains of H. pylori.

METHODS

PCR was performed using the primers amplifing vacA gene of the bacteria embeded in the gastric mucosa of 159 patients with various gastric duodenal diseases. The products of PCR were further processed for SSCP analysis and southern blot hybridization. In the meantime, vacA genes of three different SSCP-patterns from three patients with duodenal ulcers were sequenced.

RESULTS

The rate of detection of H. pylori with the method was 100%. vacA1 and vacA2, the two subtypes of vacA, were 76.5% (114/149) and 23.5%(35/149), respectively. Eight different SSCP-patterns were distributed in various gastroduodenal diseases, and that 80% of duodenal ulcers was predominated with B pattern. Sequencing of DNA indicated a diversity of vacA gene structure.

CONCLUSION

PCR/SSCP can be used in the differentiation of different strains of H. pylori in epidemology, and in the follow up study after H. pylori eradication, especially in the differentiation between H. pylori recrudescence and reinfection.

Nested case-control study of esophageal cancer in relation to occupational exposure to silica and other dusts

BACKGROUND

Standardized proportionate mortality ratio (SPMR) was found to be 2.2 (95% CI = 1.3-3.5) for esophageal cancer (EC) among workers exposed to refractory brick dust in a large iron-steel complex in China.

METHODS

A nested case-control design within a cohort of industrial workers. One hundred and twenty-five EC cases and 250 controls were identified from the death registry file. Interviews were conducted of the next of kin for past exposure information on job, domestic, and lifestyle factors. History of occupational exposure to various dusts was reconstructed from personnel files and by interviewing colleagues utilizing a job-exposure matrix.

RESULTS

After adjusting for confounders, occupational exposure to silica dust was the most important risk factor among all variables investigated, with a 2.8-fold risk and a clear dose-response by length of exposure. Alcohol drinking (OR = 1.8) and coal cooking (OR = 2.0) were risk factors and high consumption of fruit diet (OR = 0.5) and meat diet (OR = 0.6) were protective factors.

CONCLUSIONS

The relationship between occupational exposure to silica dust and the risk of EC found in an earlier SPMR study was confirmed. Ingestion of silica particles after lung clearance may increase the risk of EC among workers exposed to silica.

[The significance of detection of Helicobacter pylori in saliva]

OBJECTIVE

To explore noninvasive and effective method to detect Helicobacter pylori (Hp) in saliva.

METHODS

DNAs of saliva and gastric mucosa from 138 and 159 patients of various gastro-duodenal diseases were detected with PCR by use of primers amplifying vacA gene. The products were further processed for SSCP and Southern blot hybridization.

RESULTS

The rate of detection of Hp in saliva and gastric mucosa was 71.7% and 100% respectively. vacA(1) and vacA(2), being the two subtypes of vacA, were recognized in Hp. PCR/SSCP analysis showed a 98% identity of the strains of Hp in the saliva and gastric mucosa.

CONCLUSION

Hp could be colonized in saliva and probably transmitted orally. The new method may provide noninvasive approach for detection of Hp and could be used in the investigation of family aggregation of Hp infection.

[A study on the symptoms and diagnostic criteria of irritable bowel syndrome in Chinese]

OBJECTIVE

To explore the related symptoms of irritable bowel syndrome (IBS) and its diagnostic criteria in Chinese.

METHODS

Symptomatic IBS was diagnosed using Manning criteria in a screening of 2486 subjects in Beijing. A questionnaire study was carried out randomly by clustering samples of residential groups according to a stratified design of city, suburban and rural areas. The sample size of each area studied was in proportion with the population of the area. Symptoms were recorded in detail by trained doctors and medical students and the results underwent computer analysis by comparing their percentages in an IBS (n = 215) group with those in a non-IBS (n = 2271) group. Single factor analysis was done by using Chi square test, those factors of significance were further analyzed by logistic analysis of multifactor.

RESULTS

In the single factor analysis, as much as 22 symptoms regarding the whole GI tract and urinary bladder were considered to be significantly related to IBS. After multifactor- analysis, those symptoms of colonic origin remain to be most significant; they were: (1) abdominal pain (> 6 times/a), (2) abdominal pain accompanied by altered bowel habits (both diarrhea and constipation), (3) pain released after defecation, (4) mucus in stool.

CONCLUSION

(1) Abdominal pain accompanied by altered bowel habit and pain relieved after defecation are the essential symptoms of IBS. Manning criteria modified by adding constipation with a positive predictive value of 80%, is most suitable in the epidemiologic study as well as in clinical screening of IBS in Chinese; Rome criteria with a positive predictive value of 75% is more reliable in research work and clinical trial. (2) Exclusion of organic disease is important in the diagnosis. (3) There is an overlapping of symptoms between IBS and functional dyspepsia, but those whose colonic symptoms predominate should be diagnosed as IBS, and vise versa. (4) IBS may present extraintestinal symptoms, such as symptoms of the urinary bladder, etc.

Five new triterpene saponins from Pulsatilla patens var. multifida

Five new oleanane-type glycosides (1-5), along with two known triterpene saponins, were isolated from the roots of Pulsatilla patens var. multifida (Ranunculaceae). The structures of the new triterpene saponins were elucidated as 3-O-beta-D-glucopyranosyl(1-->2)-beta-D-galactopyranosyl hederagenin 28-O-beta-D-glucopyranosyl ester (1), hederagenin 3-O-[beta-D-glucopyranosyl(1-->2)][beta-D-glucopyranosyl(1-->6)]-beta -D-galactopyranoside (2), 3-O-beta-D-glucopyranosyl bayogenin 28-O-alpha-L-rhamnopyranosyl(1-->4)-beta-D-glucopyranosyl(1-->6)-beta -D-glucopyranosyl ester (3), 3-O-beta-D-glucopyranosyl(1-->2)-beta-D-galactopyranosyl oleanolic acid 28-O-alpha-L-rhamnopyranosyl(1-->4)-beta-D-glucopyranosyl(1-->6)-beta -D-glucopyranosyl ester (4), and 3-O-[beta-D-glucopyranosyl(1-->2)][beta-D-glucopyranosyl(1-->6)]-beta -D-galactopyranosyl hederagenin 28-O-alpha-L-rhamnopyranosyl(1-->4)-beta-D-glucopyranosyl(1-->6)-beta -D-glucopyranosyl ester (5). Structure elucidation was accomplished by 1D and 2D NMR (HMQC, HMBC, and ROESY) methods, FABMS, and hydrolysis.

UCP4, a novel brain-specific mitochondrial protein that reduces membrane potential in mammalian cells

Uncoupling proteins (UCPs) are a family of mitochondrial transporter proteins that have been implicated in thermoregulatory heat production and maintenance of the basal metabolic rate. We have identified and partially characterized a novel member of the human uncoupling protein family, termed uncoupling protein-4 (UCP4). Protein sequence analyses showed that UCP4 is most related to UCP3 and possesses features characteristic of mitochondrial transporter proteins. Unlike other known UCPs, UCP4 transcripts are exclusively expressed in both fetal and adult brain tissues. UCP4 maps to human chromosome 6p11.2-q12. Consistent with its potential role as an uncoupling protein, UCP4 is localized to the mitochondria and its ectopic expression in mammalian cells reduces mitochondrial membrane potential. These findings suggest that UCP4 may be involved in thermoregulatory heat production and metabolism in the brain.

A study of multiple biomarkers in coke oven workers--a cross-sectional study in China

We conducted a cross-sectional molecular epidemiological study of coke oven workers exposed to the established carcinogen polycyclic aromatic hydrocarbons (PAHs) to evaluate the relationships between both traditional 'exposure markers' and a series of biomarkers, including urinary 1-hydroxypyrene as a marker of internal dose, leukocyte aromatic DNA adducts as markers of biologically effective dose, serum p53 protein as a response marker and genetic polymorphisms of cytochrome P4501A1 and glutathione S-transferase MI as susceptibility markers. Twenty-five male subjects each were randomly selected from the top, middle and bottom work areas of the oven, and the control plant. They were matched for age and smoking status. The mean levels of PAH exposure, monitored by stationary and personal samplers, and of worker urinary 1-hydroxypyrene differed significantly between the top, middle and bottom of the oven and control work areas. The highest stationary and personal PAH concentrations and 1-hydroxypyrene levels were demonstrated at the top work area. Good correlations were found between the stationary PAH levels, personal PAH levels and urinary 1-hydroxypyrene levels. No positive correlations were demonstrated between aromatic DNA adduct levels and current or cumulative PAH exposure dose. In the presence of genetic polymorphisms of cytochrome P4501A1, a positive correlation was demonstrated between aromatic DNA adducts and urinary 1-hydroxypyrene levels. There was also a significant correlation between serum p53 protein levels and the cumulated benzo[a]pyrene exposure dose. Although these biomarkers have certain limitations, they are applicable to cancer epidemiology, and may contribute to our understanding of the mechanisms of carcinogenesis.

The inhibition of brain acetylcholinesterase activity of juvenile largemouth bass Micropterus salmoides by sublethal concentrations of diazinon

An effect of diazinon on brain acetylcholinesterase (AChE) activity of juvenile largemouth bass Micropterus salmoides was observed. The exposure concentration started from 1/10 of the 24-h LC50 value, 90 micrograms/liter. The exposure duration was 24 h. Statistically significant and dose-dependent reductions in the mean AChE activities we seen at 90, 180, 270, 360, and 450 micrograms/liter. The results show that juvenile brain acetylcholinesterase activities were significantly inhibited by sublethal doses of diazinon. Inhibition of brain AChE will definitely cause physiological and behavioral modifications that reduce survival ability of the animals at an early stage of growth.

Accumulation of alpha-keto acids as essential components in cyanide assimilation by Pseudomonas fluorescens NCIMB 11764

Pyruvate (Pyr) and alpha-ketoglutarate (alphaKg) accumulated when cells of Pseudomonas fluorescens NCIMB 11764 were cultivated on growth-limiting amounts of ammonia or cyanide and were shown to be responsible for the nonenzymatic removal of cyanide from culture fluids as previously reported (J.-L. Chen and D. A. Kunz, FEMS Microbiol. Lett. 156:61-67, 1997). The accumulation of keto acids in the medium paralleled the increase in cyanide-removing activity, with maximal activity (760 micromol of cyanide removed min-1 ml of culture fluid-1) being recovered after 72 h of cultivation, at which time the keto acid concentration was 23 mM. The reaction products that formed between the biologically formed keto acids and cyanide were unambiguously identified as the corresponding cyanohydrins by 13C nuclear magnetic resonance spectroscopy. Both the Pyr and alpha-Kg cyanohydrins were further metabolized by cell extracts and served also as nitrogenous growth substrates. Radiotracer experiments showed that CO2 (and NH3) were formed as enzymatic conversion products, with the keto acid being regenerated as a coproduct. Evidence that the enzyme responsible for cyanohydrin conversion is cyanide oxygenase, which was shown previously to be required for cyanide utilization, is based on results showing that (i) conversion occurred only when extracts were induced for the enzyme, (ii) conversion was oxygen and reduced-pyridine nucleotide dependent, and (iii) a mutant strain defective in the enzyme was unable to grow when it was provided with the cyanohydrins as a growth substrate. Pyr and alphaKg were further shown to protect cells from cyanide poisoning, and excretion of the two was directly linked to utilization of cyanide as a growth substrate. The results provide the basis for a new mechanism of cyanide detoxification and assimilation in which keto acids play an essential role.

FCP1, the RAP74-interacting subunit of a human protein phosphatase that dephosphorylates the carboxyl-terminal domain of RNA polymerase IIO

TFIIF (RAP30/74) is a general initiation factor that also increases the rate of elongation by RNA polymerase II. A two-hybrid screen for RAP74-interacting proteins produced cDNAs encoding FCP1a, a novel, ubiquitously expressed human protein that interacts with the carboxyl-terminal evolutionarily conserved domain of RAP74. Related cDNAs encoding FCP1b lack a carboxyl-terminal RAP74-binding domain of FCP1a. FCP1 is an essential subunit of a RAP74-stimulated phosphatase that processively dephosphorylates the carboxyl-terminal domain of the largest RNA polymerase II subunit. FCP1 is also a stoichiometric component of a human RNA polymerase II holoenzyme complex.

[The effect of interleukin-1 beta interleukin-8 in the pathogenesis of experimental colitis and evaluation of interleukin-1 receptor antagonist therapy]

OBJECTIVE

To study the effect of interleukin-1 beta and interleukin-8 in the pathogenesis of colitis and evaluate the therapeutic effect of interleukin-1 receptor antagonist(IL-1ra).

METHODS

A rat model of chronic experimental colitis was induced by administration of trinitrobenzenesulfonic acid (TNBS, 30 mg) in 50% ethanol 0.25 ml. IL-1ra was then administered intravenously with a dosage of 7 mg/kg at different times. Hydrocortisone (3 mg) i.v. administration was served as control. Tissue expression of IL-1 beta mRNA and IL-8 mRNA was then studied by in situ hybridization before and after IL-1ra administration. Histological examination and tissue myeloperoxidase (MPO) and superoxide dismutase (SOD) activities detection were also made to assess the severity of colitis.

RESULTS

An acute inflammation with ulcers, neutrophil infiltration and crypt abscess developed that evolved into a chronic inflammation with abundant fibrous connective tissue hypertrophy at 21 days. And it then recurs only after 10 mg TNBS administration. Activities of MPO and SOD correlated with severity of inflammation. Expression of IL-1 beta mRNA was detected in macrophages in lamina propria and submucosa during the whole period of inflammation. It could be also present in epithelial cells in the 3rd day of colitis. While IL-8 mRNA expression appeared at the 3rd day, and disappeared at 21th day when colitis turned into chronic. After IL-1ra administration, the expression of these two interleukins could not be detected, accompanied with alleviation of histological manifestation, decrease of MPO activity and elevation of SOD activity.

CONCLUSIONS

IL-1 beta and IL-8 were involved in the pathogenesis of colitis. IL-1ra has preventive and therapeutic effect to colitis.

[p53 gene mutation in hepatocellular carcinoma]

OBJECTIVE

To study the relationship between mutation of p53 gene and hepatocellular carcinoma (HCC).

METHOD

Sixty-five cases of HCC from Nanning prefecture of high aflatoxin (AFB1) exposure were studied by polymerase chain reaction and restrictive fragment length polymorphism (PCR-RFLP) analysis to examine the exon 7 of p53 gene in HCC.

RESULT

58.5% of the cases were found to show mutation at codon 249 of p53 gene; 63.6% for the HCCs with HBsAg negative, and 57.4% for those with HBsAg positive; 88.9% for those with metastasis, and 46.8% for those with no metastasis. The mutation rate of p53 gene was 10.0%, 55.2% and 80.8% in the well-, moderately- and poorly-differentiated HCC respectively.

CONCLUSION

AFB1 is the most important agent for the mutation at the hot-spot, and hepatitis B virus is the synergistic risk factor. Further study indicated that the p53 gene mutation is correlated with the differentiation and the metastasis of HCC and may serve as an important prognostic factor.

[The establishment of TNBS-induced experimental colitis]

OBJECTIVE

To explore the pathogenesis of inflammatory bowel disease (IBD) and to establish some indices monitoring the activity and severity of IBD.

METHODS

A rat model of experimental colitis was induced by administration of the hapten 2, 4, 6-trinitrobenzenesulfonic acid (TNBS, 30 mg) in 50% ethanol 0.25 ml as the "barrier breaker". And it then recurs only after 10 mg TNBS administration. Inflammation was assessed by gross appearance using a grading scale and by histology. Myeloperoxidase(MPO) and superioxide dismutase(SOD) activities were also measured to evaluate the severity of inflammation.

RESULTS

An acute inflammation with ulcers and neutrophil infiltration developed that evolved into a chronic inflammation with luminol narrowing and abundant fibrous connective tissue hypertrophy at 21 days. Crypt abcess were observed in some rats killed in 1 week. MPO activity was significantly elevated, while SOD decreased, in mucosa from all treated groups at all time intervals when macroscopic and microscopic mucosal injury was evident.

CONCLUSIONS

These results indicate that this model affords an opportunity to study the pathogenesis of colonic inflammatory disease and may be used to evaluate new treatments potentially applicable to IBD in humans. In addition, MPO and SOD activities could be regarded as two markers which may evaluate the severity of colonic inflammation.

Calmodulin antagonists inhibit apoptosis of CD4+ T-cells from patients with AIDS

Recent studies indicate that Fas and Fas ligand are involved in apoptosis of T-cells in HIV-infected patients. We have demonstrated that calcium/calmodulin is involved in Fas-mediated apoptosis in human T-cell lines transfected with HIV recombinant cDNA. In the present study, we examined spontaneous apoptosis of T-cells in vitro in peripheral blood obtained from 11 patients with AIDS and 8 HIV-seronegative normal donors and the effect of the calmodulin antagonists, trifluoperazine (TFP) or tamoxifen (TMX), on apoptosis. The results show that: (1) levels of spontaneous apoptosis were higher in PBMCs obtained from patients with AIDS than HIV-negative normal controls and the levels of apoptosis correlated with the severity of disease. (2) The accelerated apoptosis occurred predominantly in CD4+ cells in patients with AIDS. (3) Calmodulin antagonists inhibited the spontaneous apoptosis of CD4+ T-cells from patients with AIDS, which resulted in an increase in the ratio of CD4+ to CD8+ T-cells. (4) The inhibitory effect of calmodulin antagonists on apoptosis was more significant in patients with advanced disease (CDC category C) compared to less severe disease (CDC category B). These results indicate that calmodulin antagonists inhibit HIV-associated apoptosis of CD4+ T-cells, and imply that the calcium/calmodulin play important roles in mediating apoptosis of CD4+ T-cells induced by HIV infection.

Identification and functional characterization of DR6, a novel death domain-containing TNF receptor

Tumor nectosis factor (TNF) receptors are key players in inflammation and immune regulation. A new member of this family, termed death receptor-6 (DR6), has been identified. Like other death receptors, DR6 is a type I transmembrane receptor, possesses four extracellular cysteine-rich motifs and a cytoplasmic death domain. DR6 is expressed in most human tissues and abundant transcript was detected in heart, brain, placenta, pancreas, thymus, lymph node and several non-lymphoid cancer cell lines. DR6 interacts with TRADD, which has previously been shown to associate with TNFR1. Furthermore, ectopic expression of DR6 in mammalian cells induces apoptosis and activation of both NF-kappaB and JNK.

Analytic assessment of the various bioimpedance methods used to estimate body water

Knowledge of patient fluid distribution would be useful clinically. Both single-frequency (SF) and impedance modeling approaches are proposed. The high intercorrelation between body water compartments makes determining the best approach difficult. This study was conducted to evaluate the merits of an SF approach. Mathematical simulation was performed to determine the effect of tissue change on resistance and reactance. Dilution results were reanalyzed, and resistance and parallel reactance were used to predict the intracellular water for two groups. Results indicated that the amount of intracellular and extracellular water conduction at any SF can vary with tissue change, and reactance at any SF is affected by all tissue parameters. Modeling provided a good prediction of dilution intracellular and extracellular water, but an SF method did not. Intracellular, extracellular, and total body water were equally predicted at all frequencies by SF resistance and parallel reactance. Extracellular and intracellular water are best measured through modeling, because only at the zero and infinite frequencies are the results sensitive only to extracellular and intracellular water. At all other frequencies there are other effects.

[Risk of lung cancer among iron and steel workers in Anshan, China--case-control study]

A case-control interview study on 610 lung cancer patients and 959 controls was conducted among male workers in Anshan Iron-steel Complex. After adjusting for non-occupational risk factors, such as smoking, pulmonary disease, family history of cancer and the consumption of fruit, risks for lung cancer were significantly higher in workers engaged in smelting and rolling (OR = 1.5, 95% CI = 1.1-2.2), in the fire-resistant brick factory (OR = 2.9, 95% CI = 1.4-5.9), in general loading (OR = 2.5 95% CI = 1.0-6.1), and in coking (OR = 3.4, 95% CI = 1.4-8.5) for 15 or more years. Significant dose-response was observed for exposure to total dust and B[a]P, but not for specific chemical components of dust. The lung cancer risk increased 40% in iron and steel workers with long term occupational exposure.

[Repair of large articular cartilage defect of hip with allograft of skull periosteum]

It is very difficult to repair large articular cartilage defect of the hip. From May 1990 to April 1994, 47 hips in 42 patients of large articuler cartilage defects were repaired by allograft of skull periosteum. Among them, 14 cases, whose femoral heads were grade. IV necrosis, were given deep iliac circumflex artery pedicled iliac bone graft simultaneously. The skull periosteum had been treated by low tempreturel (-40 degrees C) before and kept in Nitrogen (-196 degrees C) till use. During the operation, the skull periosteum was sutured tightly to the femoral head and sticked to the accetabulum by medical ZT glue. Thirty eight hips in 34 patients were followed up for 2-6 years with an average of 3.4 years. According to the hip postoperative criteria of Wu Zhi-kang, 25 cases were excellent, 5 cases very good, 3 cases good and 1 case fair. The mean score increased from 6.4 before operation to 15.8 after operation. The results showed, in compare with autograft of periosteum for biological resurface of large articular defect, this method is free of donor-site morbidity. Skull periosteum allograft was effective for the treatment of large articular cartilage defects in hip.

Activation of caspases triggered by cytochrome c in vitro

Previous studies have shown that Apaf-1 and caspase-9 in the presence of cytochrome c and dATP can form an initiating complex for an apoptotic protease cascade. We have developed a cytochrome c-dependent in vitro system in which caspases downstream of this initiation complex are activated. The activation of caspase-9 from zymogen form to active dimeric protease requires intrinsic enzymatic activity. In contrast, caspase-3 and caspase-7 zymogens are proteolytically processed by active caspase-9. Activation of the above caspases is blocked by a dominant negative form of caspase-9. The in vitro system displays surprising specificity in that other caspases, including 1, 2, 4, 8, 10, and 13, are not activated.

TRUNDD, a new member of the TRAIL receptor family that antagonizes TRAIL signalling

TRAIL/Apo-2L induces rapid apoptosis of a variety of tumor cell lines. A family of tumor necrosis factor receptor-related molecules have been identified as receptors for TRAIL. Herein, we report the identification of another member of the TRAIL receptor family, TRUNDD (TRAIL receptor with a truncated death domain). The TRUNDD transcript was detected in multiple human tissues. TRUNDD is highly homologous to all known TRAIL receptors and has an extracellular TRAIL-binding domain but lacks a functional intracellular death domain and does not induce apoptosis. Consistent with an inhibitory role, ectopic expression of TRUNDD attenuated TRAIL-induced apoptosis in mammalian cells.

Caspase-9, Bcl-XL, and Apaf-1 form a ternary complex

Genetic analysis of apoptosis in the nematode Caenorhabditis elegans has revealed the cell death machine to be composed of three core interacting components. CED-4 (equivalent to mammalian Apaf-1) is a nucleotide binding molecule that complexes with the zymogen form of the death protease CED-3, leading to its autoactivation and cell death. CED-9 blocks death by complexing with CED-4 and attenuating its ability to promote CED-3 activation. An equivalent ternary complex was found to be present in mammalian cells involving Apaf-1, the mammalian death protease caspase-9, and Bcl-XL, an anti-apoptotic member of the Bcl-2 family. Consistent with a central role for caspase-9, a dominant negative form effectively inhibited cell death initiated by a wide variety of inducers.

Occupational lung diseases and global occupational health on the Net

Occupational lung disease is a major area of concern in occupational health, exhibiting a diverse panorama across countries. While pneumoconiosis is deemed to be the most common occupational disease in many developing countries, emphasis is shifting towards asbestos-related lung diseases and occupational asthma in industrialized countries. Following the Occupational Health for All strategies set forth by the World Health Organization, we propose that a model system based upon the Global Health Network can serve as an effective vehicle towards the prevention of occupational lung diseases on a global scale. It has the potential to: (1) enhance transmission of data and collaboration with the primary health care system in disease surveillance; (2) strengthen research and information transfer and (3) promote education and training at all levels of prevention, with a possible application to the interpretation of chest radiograms.

Interaction of elongation factors TFIIS and elongin A with a human RNA polymerase II holoenzyme capable of promoter-specific initiation and responsive to transcriptional activators

Affinity chromatography on columns containing the immobilized monomeric transcriptional elongation factor TFIIS or the essential large subunit, Elongin A, of the trimeric elongation factor, Elongin, was used to purify a human RNA polymerase II holoenzyme from HeLa whole cell extract. This holoenzyme contained nearstoichiometric amounts of all the general transcription factors, TFIIB, TFIID (TBP + TAFIIs), TFIIE, TFIIF, and TFIIH, required to accurately initiate transcription in vitro at the adenovirus major late promoter. It behaved as a large complex, slightly smaller than 70 S ribosomes, during gel filtration chromatography, and contained nearly half the TFIID that was present in the extract used for the affinity chromatography. It also contained the cyclin-dependent kinase CDK8, a human homologue of the Saccharomyces cerevisiae holoenzyme subunit SRB10, and many other polypeptides. Efficient interaction of holoenzyme with TFIIS or Elongin A required only the amino-terminal region of either protein. These regions are similar in amino acid sequence but dispensable for TFIIS or Elongin to regulate elongation in vitro by highly purified RNA polymerase II. The transcriptional activators GAL4-VP16 and GAL4-Sp1 activated transcription in vitro by purified holoenzyme in the absence of any additional factors.

An antagonist decoy receptor and a death domain-containing receptor for TRAIL

TRAIL, also called Apo2L, is a cytotoxic protein that induces apoptosis of many transformed cell lines but not of normal tissues, even though its death domain-containing receptor, DR4, is expressed on both cell types. An antagonist decoy receptor (designated as TRID for TRAIL receptor without an intracellular domain) that may explain the resistant phenotype of normal tissues was identified. TRID is a distinct gene product with an extracellular TRAIL-binding domain and a transmembrane domain but no intracellular signaling domain. TRID transcripts were detected in many normal human tissues but not in most cancer cell lines examined. Ectopic expression of TRID protected mammalian cells from TRAIL-induced apoptosis, which is consistent with a protective role. Another death domain-containing receptor for TRAIL (designated as death receptor-5), which preferentially engaged a FLICE (caspase-8)-related death protease, was also identified.

[GC-MS analysis of constituents of essential oils from stems of Ephedra sinica Stapf, E. intermedia Schrenk et C.A. Mey. and E. equisetina Bge]

The essential oils from the dried stems of Ephedra sinica, E. intermedia and E. equisetina were analyzed by GC-MS qualitatively and GC quantitatively. One hundred and twenty-seven constituents were identified, l-alpha-terpineol (31.64%) in E. sinica, 1,4-cineole (12.80%) in E. intermedia and hexadecanoic acid (26.22%) in E. equisetina being the main constituents.

Test for qualitative interaction of clinical significance

We generalize the problem of detecting qualitative interaction between treatments and subsets in a two treatment clinical trial to the more practical problem of detecting a qualitative interaction greater than a non-negative value d, corresponding to the minimal treatment difference of clinical significance. We develop a test based on simultaneous confidence intervals for the generalized problem under the assumption of normality. The proposed test is easy to implement, either by hand calculation or through the use of virtually any existing statistical software. We derive explicit power function for the proposed test and give examples to illustrate the procedures.