Comparison of SERCA1 and SERCA2a expressed in COS-1 cells and cardiac myocytes

Cultured COS-1 cells, as well as chicken embryonic and neonatal rat cardiac myocytes, were infected with recombinant adenovirus vectors to define limiting factors in the expression and Ca2+ transport function of recombinant sarcoplasmic-endoplasmic reticulum Ca(2+) (SERCA) isoforms. Titration experiments showed that all COS-1 cells and myocytes in culture could be infected by an adenovirus titer of 10 plaque-forming units (pfu) per seeded cell. Raising the adenovirus titer further yielded higher protein expression up to an asymptotic limit for functional, membrane-bound SERCA protein. The asymptotic behavior of SERCA expression was not transcription related but was due to posttranscriptional events. The minimal (-268) cardiac troponin T (cTnT) promoter was a convenient size for adenovirus vector construction and manifested tight muscle specificity. However, its efficiency was lower than that of the nonspecific cytomegalovirus (CMV) promoter. At any rate, identical maximal levels of SERCA expression were obtained with the CMV and the cTnT promoter, as long as the viral titer was adjusted to compensate for transcription efficiency. A maximal threefold increase of total SERCA protein expression over the level of the endogenous SERCA of control myocytes was reached (a sevenfold increase compared with the endogenous SERCA of the same infected myocytes due to reduction of endogenous SERCA after infection). In contrast with previous reports [Ji et al. Am. J. Physiol. 276 (Heart Circ. Physiol. 45): H89-H97, 1999], a higher kinetic turnover was demonstrated for the SERCA1 compared with the SERCA2a isoform as shown by a 5.0- versus 2.6-fold increase in calcium uptake rate accompanying maximal expression of recombinant SERCA1 or SERCA2a, respectively. This information is deemed necessary for studies attempting to modify myocardial cell function by manipulation of SERCA expression.

A case-control study of lung cancer and environmental tobacco smoke among nonsmoking women living in Shanghai, China

INTRODUCTION

The incidence of lung cancer in women living in China is among the highest in the world but it does not appear that tobacco smoking is a major risk factor for lung cancer. As tobacco smoking is highly prevalent in Chinese men, exposure to environmental tobacco smoke (ETS) may play an important role in the development of lung cancer in Chinese women who never smoked. We conducted the present investigation because previous studies did not account for dietary habits or indoor air pollution from Chinese-style cooking and they did not assess the effect of occupational exposure to ETS.

METHODS

A population-based, case-control study was conducted to evaluate the relationship between lung cancer and exposure to ETS among nonsmoking women living in Shanghai, China. Five-hundred and four women diagnosed with incident, primary lung cancer between February 1992 and January 1994 were identified through the population-based Shanghai Cancer Registry. A control group of 601 nonsmoking women was selected randomly from the Shanghai Residential Registry, and was approximately frequency-matched to the age distribution of the lung cancer cases. Information on lifetime domestic and occupational exposure to ETS was obtained through face-to-face interviews. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated by unconditional logistic regression.

RESULTS

The OR for ever exposed to ETS from spouses was 1.1 (95% CI: 0.8-1.5), and the OR for ever exposed to ETS at work was 1.7 (95% CI: 1.3-2.3). Furthermore, the OR increased with increasing number of hours of daily exposure to ETS in the workplace and with increasing number of smoking co-workers. No associations were found for exposure to ETS during childhood.

CONCLUSIONS

The main findings of the present study are that long-term occupational exposure to ETS, both alone or in combination with exposures at home, conferred an increased risk of lung cancer among women who never smoked. The inconsistency of the results regarding exposure to ETS at home and at work may have been due to lower exposures at home.

Overlapping effects of S3 stalk segment mutations on the affinity of Ca2+-ATPase (SERCA) for thapsigargin and cyclopiazonic acid

Chimeric exchanges and mutations were produced in the Ca(2+)-ATPase (SERCA) to match (in the majority of cases) corresponding sequences of the Na(+),K(+)-ATPase. The effects of these mutations on the concentration dependence of the specific Ca(2+)-ATPase inhibition by thapsigargin (TG) and cyclopiazonic acid (CPA) were then determined. Extensive chimeric mutations on the large cytosolic loop, on the S4 stalk segment, and on the M3 transmembrane segments produced little or no modification of the Ca(2+)-ATPase sensitivity to either inhibitor. On the other hand, the presence of a six amino acid Na(+), K(+)-ATPase sequence within the S3 stalk segment of the Ca(2+)-ATPase raised 60-fold the apparent K(i) for TG and 250-fold the apparent K(i) for CPA. More limited mutations within the same S3 segment, however, affected differently the concentration dependence of the Ca(2+)-ATPase inhibition by TG or CPA. Specifically, single mutation of Phe256 to Val increased 20-fold the apparent K(i) for TG, while having very little effect on the apparent K(i) for CPA. These findings indicate significant overlap of the TG and CPA binding domains within the S3 stalk segment of the Ca(2+)-ATPase, where the contribution of each protein residue is dependent on the structures of the two inhibitors. Saturating concentrations of either or both TG and CPA produce an identical reduction of the affinity of the ATPase for ATP, suggesting that only one inhibitor can bind at any time due to significant overlap of their binding domains. It is suggested that perturbations produced by binding of either inhibitor within the stalk segment interfere with the long-range functional linkage between ATP utilization in the ATPase cytosolic region and Ca(2+) binding in the membrane-bound region.

[The role of NF-kappa B in the TNF-alpha-induced endothelial cell apoptosis]

OBJECTIVE

To investigate whether TNF-alpha could activate the signaling pathway-NF-kappa B/I-kappa B alpha required for the expression of inducible nitric oxide synthase (iNOS) to induce endothelial cell apoptosis by nitric oxide (NO).

METHODS

Aminoguanidine (AG, an inhibitor of iNOS) and Pyrrolidine dithiocarbamate (PDTC, an inhibitor of NF-kappa B) were evaluated for their influence on the apoptosis of cultured bovine pulmonary artery endothelial cells (BPAEC) induced by TNF-alpha. Apoptosis was confirmed by morphology, ultrastructural observation, agarose gel electrophoresis of DNA, and percentage of DNA fragmentation. Western blot analyses were used to detect the expression of iNOS and the levels of I-kappa B alpha in BPAEC exposed to TNF-alpha. Electrophoretic mobility shift assays (EMSA) were used to determinate the activity of NF-kappa B in BPAEC.

RESULTS

TNF-alpha induced BPAEC apoptosis (18.0 +/- 4.3)% in a concentration- and time-dependent manner. Both AG and PDTC attenuated the apoptosis of BPAEC induced by TNF-alpha, with peventages of DNA fragmentation in 2, 4, 10 mmol/L AG being (10.0 +/- 2.2)%, (7.8 +/- 1.2)% and (8.2 +/- 1.3)% vespectively. In BPAEC after TNF-alpha exposure, Western blot analyses revealed the expression of iNOS and the decrease in I-kappa B alpha. EMSA demonstrated an impermanency increase in NF-kappa B binding activity.

CONCLUSIONS

TNF-alpha can induce endothelial cell apoptosis by NO, which is produced by increasing iNOS expression and activating the signal pathway-NF-kappa B.

Determination of indinavir in human cerebrospinal fluid and plasma by solid-phase extraction and high-performance liquid chromatography with column switching

A rapid, sensitive and robust sample preparation procedure for the quantitative determination of indinavir in human cerebrospinal fluid (CSF) and plasma is described. Indinavir and the internal standard were isolated from CSF or plasma samples by cation-exchange solid-phase extraction with SCX cartridges, while the chromatographic separation was adopted from a previous method, using a cyano column connected by a switching valve to a C18 column. UV detection was set at 210 nm. The standard curve was linear over the concentration range of 2 to 2000 ng/ml in CSF and 5 to 2000 ng/ml in plasma. The intra-day coefficients of variation at all concentration levels were < or = 5.9%. The inter-day consistency was assessed by running QC samples during each daily run. The coefficients of variation for quality control samples in both matrixes were < or = 6.1%. The method has been utilized to support clinical pharmacokinetic studies.

Function of estrogen receptor tyrosine 537 in hormone binding, DNA binding, and transactivation

The human estrogen receptor (hER) is a ligand-activated transcription factor which, like many other members of the nuclear receptor protein family, exhibits a dimerization-dependent transcriptional activation. Several previous reports have provided evidence of the phosphorylation of the hER at tyrosine 537 (Y537). However, the exact function of a putative phosphorylation at this site remains controversial. Using a yeast transactivation assay, and in vitro biochemical approaches, we show that phosphorylation of tyrosine 537 is not required for the hER to bind hormone, or to activate transcription. An hER tyrosine 537 to phenylalanine (Y537F) mutant retains 70-75% of the transactivation potential of wild type hER in a yeast reporter system. Furthermore, the mutated receptor exhibits wild type hormone and DNA binding affinities. However, this mutation results in a decrease in receptor stability as measured by a decrease in the extent of hormone binding over time. The most striking difference between the wild type and Y537F hER is in the estradiol binding kinetics. Whereas the off-rate for estradiol exhibits a two-state binding mechanism, the Y537F mutant hER exhibits a monophasic estradiol off-rate. On the basis of these data and other reports describing the structure and activity of Y537 mutations, as well as knowledge of the three-dimensional structure of the hER ligand binding domain, we propose an alternate model wherein Y537F mutation favors an "open" pocket conformation, affecting the estrogen binding kinetics and stability of the hormone-bound, transcriptionally active "closed" pocket conformation. Although its phosphorylation is not essential for function of the hER, Y537 is nevertheless a critical residue intricately involved with the conformational changes of the hER and its ability to activate transcription.

Isolation and identification of xylitol dehydrogenase gene from Trichoderma reesei

A cDNA sub-library from the fungus Trichoderma reesei grown on xylan was constructed in S.cerevisiae recombinant strain H475 harboring a xylose reductase (XR) gene from Pichia stipitis. The xylitol dehydrogenase (XDH) gene was screened from sub-library on a SC selective medium in which xylose was used as a sole carbon source. The length of XDH gene, xdh1, was about 1.3 kb. Southern, Northern and Western blots were carried out, indicating that xdh1 has high affinity with T.reesei and the molecular weight of the xylitol dehydrogenase from T.reesei was about 40 kDa. The strain HX1 harboring both the XR gene from P.stipitis and the XDH gene from T.reesei was able to grow on the xylose medium and converted more than 90% of the xylose into xylitol, ethanol, and other by-products.

[Transforming growth factor-beta1 induced cultured human trabecular cells to produce elastin]

OBJECTIVE

To understand transforming growth factor-beta(1) (TGF-beta(1)) inducing cultured human trabecular cells (HTCs) to produce elastin and to approach the effect of resistance of aqueous outflow in the pathogenesis and mechanism of primary open angle glaucoma (POAG).

METHODS

Trabecular meshwork's specimens were collected from twelve normal eyeballs of six human donors under six years of age within 24 hours after death. HTCs were primarily cultured and subcultured. Cultured cells were observed under light and electron microscopes. Laminin (LN) and IV collagen (IV C) in extracellular matrix (ECM) were immunohistochemically stained by S-P method. The third passage confluent cells after two weeks were divided into three groups: control group, TGF-beta(1) group and neutralizing antibody of TGF-beta(1) group. Concentration of neutralizing antibody of TGF-beta(1) was 30 microg/ml. After culturing for two weeks, elastin in the media of three groups was respectively determined by western blotting from sodium dodecylsulfate-polyacrylamide gel electrophoresis using anti-human aortic alpha-elastin rabbit serum, biotin conjugated goat anti-rabbit IgG and anti-biotin conjugated horse radish peroxidase.

RESULTS

Cultured HTCs were identified from cultured cell's growing characteristics, morphological features under light and electron microscopes, and stained peculiarities of LN and IV C in ECM. With western blotting, elastin in the control group was not detected, elastin in TGF-beta(1) group was detected, and elastin in neutralizing antibody of TGF-beta(1) group was not detected.

CONCLUSION

TGF-beta(1) induces cultured HTCs to produce elastin, which the neutralizing antibody of elastin can antagonize; the increase of the amount of elastin may aggravate its stacking in ECM and increase the resistance of aqueous outflow in trabecular meshwork, leading to the occurrence of glaucoma.

Lung cancer and indoor air pollution arising from Chinese-style cooking among nonsmoking women living in Shanghai, China

Associations between indoor air pollution from Chinese-style cooking and lung cancer have been found in several investigations. To provide more detailed estimates of the associations while accounting for key confounding factors, we conducted a population-based, case-control study of lung cancer among nonsmoking women living in Shanghai, the People's Republic of China. Five hundred four incident, primary lung cancer cases diagnosed from February 1992 through January 1994 were identified through the population-based Shanghai Cancer Registry. A control group of 601 nonsmoking women was selected randomly from the Shanghai-Residential Registry, and they were frequency-matched to the expected age distribution of the cases. Exposure to indoor air pollutants from Chinese-style cooking was ascertained through in-person interviews. We estimated adjusted odds ratios (OR) and 95% confidence intervals (CI) by unconditional logistic regression. There were similar patterns of excess risk for exposure to indoor air pollutants from Chinese-style cooking across different histological types of lung cancer. Women who did not have a separate kitchen experienced a 28% increased risk of lung cancer (OR = 1.28; 95% CI = 0.98-1.68). We found little association with area of the windows of the apartment where subjects had lived for the longest period of time. Heating cooking oils to high temperatures was associated with a 1.64-fold increased risk of lung cancer (95% CI = 1.24-2.17). An 84% excess risk was found among women who most often cooked with rapeseed oil (OR = 1.84; 95% CI = 1.12-3.02). Lung cancer risks were also related to "considerable" smokiness of the kitchen during cooking (OR = 2.38; 95% CI = 1.58-3.57), frequent eye irritation during cooking (OR = 1.68; 95% CI = 1.02-2.78), to a more than weekly use of frying (OR = 2.09; 95% CI = 1.14-3.84) and deep-frying (OR = 1.88; 95% CI = 1.06-3.32). This population-based case-control study confirmed that exposure to indoor air pollution from Chinese-style cooking, especially cooking unrefined rapeseed oil at high temperatures in woks, may increase the risk of lung cancer.

Risk of developing lung cancer in relation to exposure to fumes from Chinese-style cooking

In an evaluation of the association between exposure to indoor air pollution from Chinese-style cooking and the risk of lung cancer, epidemiologic and experimental studies were reviewed. The 9 case-referent studies that were identified showed consistent positive associations between the risk of lung cancer and a variety of indices of exposure to indoor air pollution arising from Chinese-style cooking. Three experimental studies showed that volatile emissions from oils heated in woks are mutagenic in several in vitro short-term test systems. Several toxic agents, including some accepted or suspected carcinogens, have been detected in the emissions of the heated cooking oils. While experimental data support the epidemiologic data, it may be premature to conclude that the association is causal. However, simple precautions can be taken to reduce the risk in the event that exposure to indoor air pollution arising from Chinese-style cooking is indeed a cause of lung cancer.

[Influence of cell growth factors on transferrin gene expression of human lens epithelial cells in culture]

OBJECTIVE

To assess the influence of transforming growth factor-beta(1) (TGF-beta(1)) and basic fibroblast growth factor (bFGF) on the transferrin mRNA levels of cultured human lens epithelial cells.

METHODS

Lens anterior capsules were collected from 40 eyeballs of 20 human donors under 3 years of age within 24 hours after death. Lens epithelial cells were primarily cultured and subcultured. TGF-beta(1) (1 microg/L) and bFGF (250 microg/L) were added to the 3rd passage cells when they became confluent after their growth for 2 weeks. The total cellular RNA was extracted from cultured cells by guanidine isothiocyanate, etc. after the growth factors acting for 3 days. Transferrin mRNA levels were determined by a Northern blot analysis with a probe.

RESULTS

In comparison with the control group, the expressions of transferrin in the growth factor treatment groups were obviously increased. In comparison with bFGF group, transferrin mRNA level in TGF-beta(1) group was obviously increased.

CONCLUSIONS

TGF-beta(1) and bFGF upregulate transferrin gene expression of cultured lens epithelial cells remarkably, can reduce lenticular oxidative damaging process in which transferrin participates and play an important role in the pathological mechanism of cataract formation after extracapsular cataract extraction.

Mercaptopyridine-N-oxide, an NADH-fumarate reductase inhibitor, blocks Trypanosoma cruzi growth in culture and in infected myoblasts

The enzyme NADH-fumarate reductase is not found in mammalian cells but it is present in several parasitic protozoa including Trypanosoma cruzi, the parasite that causes Chagas' disease. This study shows that the drug 2-mercaptopyridine-N-oxide (MPNO) inhibits NADH-fumarate reductase purified from T. cruzi (ID50 = 35 microM). When added to intact cells, MPNO inhibited the growth of T. cruzi epimastigotes in culture (ID50 = 0.08 microM) as well as the infection of mammalian myoblasts by T. cruzi trypomastigotes (ID50 = 20 microM). At a concentration of 2.4 microM, MPNO also inhibited the growth of amastigotes (intracellular dividing forms) in cultured mammalian myoblasts. Supplementation of culture media with 5 mM succinate, the product of fumarate reductase, partially protected against the inhibition of the growth of epimastigotes by MPNO. Moreover, MPNO inhibited the accumulation of succinate in cultures of epimastigotes, as measured by high performance liquid chromatography. Although MPNO may have other intracellular targets in addition to fumarate reductase, these results support the hypothesis that compounds which inhibit the enzyme fumarate reductase may be potential chemotherapeutic agents against Chagas' disease.

[Calf trabecular cell culture in vitro, morphological and cytoskeletal ultrastructures and kinetics investigation]

OBJECTIVE

To establish the method of culturing calf trabecular cells (CTCs) in vitro, to understand the morphology and function of CTCs, to probe into the effect of resistance of aqueous outflow in the pathogenesis and mechanism about primary open angle glaucoma(POAG). To direct the clinical using of drugs and to open up new antiglaucomatous medicine by pharmacological studies of CTCs.

METHODS

Trabecular meshwork was collected from twenty eyeballs of calf donors after slaughter. The tiusse was primarily cultured and cells were subcultured. The growing characteritics and morphological features of cultured primary and passaged cells were observed by light and electron microscopes. Cell kinetics of the third and tenth passaged cells were analysed using autoradiography and flow cytometry. The influence of the antiglaucomatous drugs 0.25 mg.ml-1 epinephrine (EPI) and 0.025 mg.ml-1 dipivalyl epinephrine (DPE) on cell kinetics of the third passaged cells was studied.

RESULTS

The growing characteritics and morphological features of cultured CTCs were as same as those of human trabecular cells. Growing types of CTCs included most of epitheial cell and few of fibroblast. The amount of cellular microfilaments was reduced, DNA synthesis time(Ts) and cell cycle time(Tc) were obviously prolonged with passaged increasing. Antiglaucomatous drugs-EPI (0.25 mg.ml-1) and DPE (0.025 mg.ml-1) made microfilaments dissolving, Ts and Tc obviously prolonging.

CONCLUSION

Establishing the method of culturing CTCs in vitro and understanding their morphology, function and pharmacological effects provided an important information for studying human trabecular cells and probing into the effect of resistance of aqueous outflow in the pathogenesis and mechanism about POAG. These studies indicated that antiglaucomatous drugs-EPI (0.25 mg.ml-1) and DPE (0.025 mg.ml-1) influenced obviously microfilaments and cell kinetics of the third passaged cells and suggested that it is not to be ignored that 1% EPI and 0.1% DPE may make CTCs' microfilaments dissolving and may inhibit CTCs' division and proliferation when they are used in clinical therapy.

[Influence of transforming growth factor-beta1 on actin in cultured human trabecular cells]

OBJECTIVE

To understand transforming growth factor-beta(1) (TFG-beta(1)) influencing microfilament actins in cultured human trabecular cells (HTCs) and approach to the effect of resistance of aqueous outflow in the pathogenesis and mechanism of primary open angle glaucoma (POAG).

METHODS

Trabecular meshwork was collected from 68 eyeballs of 34 human donors under 6 years old within 24 hours after death. HTCs were primarily cultured and subcultured. Cultured cells were observed by light and electron microscopes. Laminin (LN) and IVcollagen (IVC) in extracellular matrix (ECM) were immunohistochemically stained by S-P method. Various doses (0, 1, 5 ng/ml) of TFG-beta(1) and 30 microg/ml neutralizing antibody of TFG-beta(1) were respectively added to the third passage cells before confluence and acted for 6, 12, 24 hours. Stress fibers stained with fluorescein isocyanate (FITC)-phalloidin were observed under light and electron microscopes. Various doses (0, 0.5, 1, 5 ng/ml) of TFG-beta(1) and 30 microg/ml neutralizing antibody of TFG-beta(1) were respectively added to the third passage cells after confluence for one week and acted for 6, 12, 24, 48 hours. The positive numbers of labeled F-actins were quantitatively evaluated by flow cytometry. Various doses (0, 0.5, 1, 5 ng/ml) of TFG-beta(1) and 30 microg/ml neutralizing antibody of TFG-beta(1) were respectively added to the third passage cells after confluence for one week and acted for 6, 12, 24, 36, 48 hours. The amount of beta-actin mRNA expression was semi-quantitatively evaluated by densitometry with reverse transcription-polymerase chain reaction (RT-PCR) using specific oligonucleotide primers for beta-actin and glyceraldehyde-3-phosphate dehydrogenase (G3PDH) as an internal standard.

RESULTS

According to the growing characteristics and morphological features of the cultured cells, they were identified as HTCs. In comparison with the control group, TGF-beta(1) could increase the stress fibrous bundle, the contents of F-actins and the expression of beta-actin mRNA; the effects of TFG-beta(1) appeared time dependent and were antagonized by neutralizing antibody of TFG-beta(1). When TFG-beta(1) was at higher concentration and longer acting time, cell proliferation was inhibited, cell membrane ruptured and cells peeled off in cultured HTCs before confluence.

CONCLUSIONS

Application of reverse transcription-semiquantitative PCR can promote the pathogenic research of POAG at genetic level, in a certain extent, TFG-beta(1) can obviously upregulate microfilament actins in the confluent HTCs, enhance the contractility of trabecular cells and decrease the resistance of aqueous outflow in trabecular meshwork.

Recombinant adenovirus is an efficient and non-perturbing genetic vector for human dendritic cells

Recombinant adenoviral vectors have promise for human gene therapy because of efficient transgene expression in nondividing primary cell types. Dendritic cells (DC) have potential as adjuvants for immune therapy, since they are specialized to capture antigens to form MHC-peptide complexes, migrate to T cell areas in the lymph node, and activate T cells including CD4+ helpers and CD8+ cytotoxic T lymphocytes (CTL). We show that several current chemical and physical transfection methods allow < 2 % of DC to express reporter genes but that recombinant adenoviruses, encoding the reporter genes green fluorescent protein and LacZ, efficiently transfect monocyte-derived human DC. Immature DC, generated with IL-4 and GM-CSF, are transfected to 95% efficiency, while mature DC show reduced transfection (50%) and gene expression. Adenovirus-transfected, immature DC exhibit several critical functions. The DC can differentiate in the presence of lipopolysaccharide or a monocyte-conditioned medium to express the surface markers of mature, T cell stimulatory DC including CD25, CD83, and high levels of CD86 and HLA-DR. Transfected DC can also secrete high levels of IL-12 and are potent inducers of T cell growth. Transgene expression in DC is stable for at least 6 days in the presence of the DC survival factor, TRANCE. Therefore adenoviral infection does not perturb the maturation and function of DC. The efficiency of adenoviral-mediated gene transfer prompts the evaluation of this vector in studies of DC biology, including the expression of antigens for active immune therapy.

Roles of free GPIs in amastigotes of Leishmania

Glycosylated phosphatidylinositols (GPIs) are abundant cell surface molecules of the Leishmania. Amastigote-specific GPIs AmGPI-Y and AmGPI-Z, both ethanolamine (EtN)-containing glycolipids, were identified in Leishmania amazonensis. A paucity of GPI-anchored proteins in amastigotes of L. amazonensis made the kinetoplastid suitable for evaluating the importance of free (i.e. unconjugated to protein or polysaccharide) GPIs. A strain deficient in both AmGPI-Y and AmGPI-Z was produced by stable transfection of wild-type Leishmania with a GPI-phospholipase C gene. Phosphatidylinositol deficiency was not detected in the transfectants. GPI-deficient promastigotes infected murine macrophages in vitro and differentiated into amastigotes whose growth was arrested within the host cells. Cytostasis of amastigotes was also observed during axenic culture of GPI-deficient parasites. In a hamster model of leishmaniasis, GPI-deficient promastigotes produced smaller lesions with 20-fold fewer amastigotes than infections with control parasites. Together, these observations indicate that EtN-GPIs may be essential for amastigote viability, replication, and/or virulence. Implicit in these observations is the notion that drugs targeted against the GPI biosynthetic pathway might be of value in the management of human leishmaniasis.

[A study on porins of Escherichia coli HX88108]

To investigate the relationship between porins deficiency and the resistance of Escherichia coli HX88108. The porins of Escherichia coli HX88108 were studied by SDS-PAGE and were compared with the porins of standard strains. The result showed that E. coli HX88108 did not lose OmpF and OmpC, and the molecular weights of these two porins were 38 kd and 37 kd respectively. There is no relationship between the resistance of Escherichia coli HX88108 and porins deficiency.

Recombinant adenovirus is an efficient and non-perturbing genetic vector for human dendritic cells

Recombinant adenoviral vectors have promise for human gene therapy because of efficient transgene expression in nondividing primary cell types. Dendritic cells (DC) have potential as adjuvants for immune therapy, since they are specialized to capture antigens to form MHC-peptide complexes, migrate to T cell areas in the lymph node, and activate T cells including CD4+ helpers and CD8+ cytotoxic T lymphocytes (CTL). We show that several current chemical and physical transfection methods allow < 2 % of DC to express reporter genes but that recombinant adenoviruses, encoding the reporter genes green fluorescent protein and LacZ, efficiently transfect monocyte-derived human DC. Immature DC, generated with IL-4 and GM-CSF, are transfected to 95% efficiency, while mature DC show reduced transfection (50%) and gene expression. Adenovirus-transfected, immature DC exhibit several critical functions. The DC can differentiate in the presence of lipopolysaccharide or a monocyte-conditioned medium to express the surface markers of mature, T cell stimulatory DC including CD25, CD83, and high levels of CD86 and HLA-DR. Transfected DC can also secrete high levels of IL-12 and are potent inducers of T cell growth. Transgene expression in DC is stable for at least 6 days in the presence of the DC survival factor, TRANCE. Therefore adenoviral infection does not perturb the maturation and function of DC. The efficiency of adenoviral-mediated gene transfer prompts the evaluation of this vector in studies of DC biology, including the expression of antigens for active immune therapy.

[A case-control study on relationship between body mass index and lung cancer in non-smoking women]

OBJECTIVE

To investigate the relationship between body mass index (BMI) and lung cancer in non-smoking women.

METHODS

A population-based case-control study on lung cancer in non-smoking women was conducted during February 1992 to December 1993 in Shanghai. Totally, 504 cases of lung cancer of non-smoking women and 601 population controls were studied.

RESULTS

The risk of lung cancer increased with the decrease of BMI. The odds ratio of lung cancer in non-smoking women was 1.95, as compared to controls with the highest quartile of their BMI, with a dose-response pattern (P < 0.0002 with chi(2) test for trend), adjusted for age, schooling and income. Non-conditional logistic regression analysis was used to adjust for some main risk factors found in other studies carried out at home, such as passive smoking, tea drinking, eye irritation by cooking oil fume, kinds of cooking oils, pulmonary tuberculosis, family history of lung cancer, age of menarche, menstrual cycle and dietary nutrition (including intake of vitamins C and E, beta-carotene, total fat and calorie), was used to adjust. There still existed relationship between BMI and lung cancer in non-smoking women after adjustment for those factors. Stratification analysis showed that there was relationship mainly between BMI and lung adenocarcinoma.

CONCLUSION

BMI may be a risk factor for lung cancer in non-smoking women.

[Human trabeculer cells in culture and cell identification]

PURPOSE

To establish the method of culturing human trabecular cells(HTCs) in vitro and to determine identifyng main points concerning cultured HTCs.

METHODS

Trabecular meshwork, corneal and scleral tissue were collected from sixty-eight eyeballs of thirty-four human donors less than six years of age within 24 hours after death. The tissues were primarily cultured and the cells subcultured. Cultured cells were observed by light and electron microscopes. Fibronectin(FN), laminin(LN) and IV collagen (IV C) in extracellular matrix(ECM) of the cultured cells were immunohistocytochemically stained by S-P method.

RESULTS

HTCs easily grew in the event of young donors and short-time drawing materials. Trabecular meshwork should be accurately separated. Techniques in primary culture, and time and proportion in subculture should be suitabled. Experimental studies should select the third to fifth passages. The growing characteristics, morphological features of cultured HTCs under light and electron microscopes differed from those of corneal and scleral cells adjoining them. Ultramicrostucture distinguished HTCs from corneal interstitial cells. ECM stained by S-P method distinguished HTCs from scleral fibroblast.

CONCLUSIONS

These studies suggest that it is not difficult to culture HTCs in general culturing condition as long as the main points about culturing them are known-well. The identification of cultured HTCs must be combined with three aspects: the growing characteristics and morphological features of cultured cells under light and electron microscopes, and the immunohistochemical stained peculiarities of FN, LN and IV C in ECM of cultured cells. To establish the method of culturing HTCs in vitro and to determine identifyng main points concerning cultured HTCs become an essential condition and an important guarantee in order to investigate the pathogenesis and mechanism on primary open angle glaucoma(POAG) deeply.

Mta has properties of an RNA export protein and increases cytoplasmic accumulation of Epstein-Barr virus replication gene mRNA

The Epstein-Barr virus (EBV) Zta and Mta regulatory proteins were previously found to be required for efficient replication of oriLyt in cotransfection-replication assays, but the contribution of Mta to the replication process was unknown. We now demonstrate that Mta regulates replication gene expression. Using the polymerase processivity factor BMRF1 as an example, we found that in transfected cells, total BMRF1 mRNA levels were unaffected by Mta but that the amounts of cytoplasmic BMRF1 RNA and protein were greatly increased in the presence of Mta. Mta also increased cytoplasmic accumulation of the BALF2, BALF5, BSLF1, and BBLF4 replication gene mRNAs but did not affect cytoplasmic levels of BBLF2/3 mRNA. Thus, five of the six core replication genes require Mta for efficient accumulation of cytoplasmic RNA. The contribution of Mta to posttranscriptional RNA processing was examined. Examination of Mta localization in transfected cells by indirect immunofluorescence revealed that Mta colocalized with the splicing factor SC35. We also found that Mta has RNA binding activity. Glutathione S-transferase-Mta bound to BMRF1 and BMLF1 transcripts but not to a control cellular gene RNA. Mta contains a consensus leucine-rich nuclear export signal. Such signal sequences are characteristic of proteins that undergo nuclear export. Examination of Mta localization in a heterokaryon assay provided evidence that Mta shuttles between the nucleus and the cytoplasm. Our experiments indicate that Mta functions in RNA processing and transport and mediates cytoplasmic accumulation of a number of EBV early mRNAs.

Respiration and oxidative phosphorylation in the apicomplexan parasite Toxoplasma gondii

Respiration, oxidative phosphorylation, and the mitochondrial membrane potential (DeltaPsi) of tachyzoites of the apicomplexan parasite Toxoplasma gondii were assayed in situ using very low concentrations of digitonin to render their plasma membrane permeable to succinate, ADP, safranin O, and other small molecules. The rate of basal respiration was slightly increased by digitonin when the cells were incubated in medium containing succinate. ADP promoted an oligomycin-sensitive transition from resting to phosphorylating respiration. Respiration was sensitive to antimycin A and cyanide, and N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) was oxidized by antimycin A-poisoned mitochondria. The addition of ADP after TMPD/ascorbate also resulted in phosphorylating respiration. The antitoxoplasmosis drug atovaquone, at a very low concentration (0.03 microM), totally inhibited respiration and disrupted the mitochondrial membrane potential. Atovaquone was shown to inhibit the respiratory chain of T. gondii and mammalian mitochondria between cytochrome b and c1 as occurs with antimycin A1. Phosphorylation of ADP could not be obtained in permeabilized tachyzoites in the presence of either pyruvate, 3-oxo-glutarate, glutamate, isocitrate, dihydroorotate, alpha-glycerophosphate, or endogenous substrates. Although ADP phosphorylation was detected in the presence of malate, this activity was rotenone-insensitive and was probably due to the conversion of malate into succinate through a fumarate reductase activity that was detected in mitochondrial extracts. Together these results provide the first direct biochemical evidence that the respiratory chain and oxidative phosphorylation are functional in apicomplexan parasites, although the terminal respiratory pathway is different from that in the mammalian host.

Growth inhibitory effect of juvenile hormone analogues on epimastigotes of Trypanosoma cruzi

Several compounds, structurally related to the insect growth regulator Fenoxycarb, exhibited interesting inhibition action to control proliferation of Trypanosoma cruzi, the parasite responsible for Chagas' disease. Some of these drugs were shown to be potent growth inhibitors of this parasite. All of these drugs had previously presented juvenoid activity on several non-related bug species such as Tenebrio molitor, Galleria mellonella, Dysdercus cingulatos, and Pyrrhocoris apterus.

Analysis of centrosome abnormalities and angiogenesis in epidermal-targeted p53172H mutant and p53-knockout mice after chemical carcinogenesis: evidence for a gain of function

We previously developed a transgenic mouse model that expresses in the epidermis a murine p53172R-->H mutant (p53m) under the control of a human keratin-1-based vector (HK1.p53m). In contrast to mice with wild-type p53 and p53-knockout mice, HK1.p53m mice exhibit increased susceptibility to chemical carcinogenesis, with greatly accelerated benign papilloma formation, malignant conversion, and metastasis. In the study presented here, we examined the expression pattern of several differentiation markers and observed that p53m tumors exhibited a less differentiated phenotype than tumors elicited in non-transgenic mice. Metastasis in p53m tumors was also associated with a poorly differentiated phenotype. To determine whether genomic instability was associated with a putative gain-of-function role for this p53m, in situ examination of centrosomes was performed in HK1.p53m and equivalent p53-null papillomas. In contrast to HK1.p53m papillomas, which had centrosome abnormalities at high frequencies (75% of cells contained more than three centrosomes/cell), p53-null tumors exhibited few abnormal centrosomes (4% of cells contained more than three centrosomes/cell). To determine whether angiogenesis played a role in the rapid progression of p53m tumors, the expression of vascular endothelial growth factor, a promoter of angiogenesis, and thrombospondin-1, an inhibitor of angiogenesis, was examined in tumors derived from either p53m or p53-knockout mice. Regardless of their p53 status (wild type, p53m, p53-/-), all of the papillomas exhibited similar levels of vascular endothelial growth factor expression and decreased expression of thrombospondin-1 as did normal epidermis. In addition, tumors from different p53 genotypes showed a similar density of blood vessels. Because p53 status did not appear to play an overt role in angiogenesis, these data suggest that p53m accelerates tumorigenesis primarily by exerting a gain of function associated with genomic instability.