[Research on the recombinant plasmid pDJH2 of L. interrogans serovar lai: sequencing and alignment with other known bacterial Omp sequence]

The Leptospira whole cell vaccine (LWCV) currently used in China is safe and effective, out the immunity following vaccination with two doses of the fluid medium vaccine is of low order. The duration of immunity conferred by this vaccine is rather short, six months or at most one year. Therefore, it is necessary to develop new generation vaccines against Leptospirosis for the developing world. In this paper we report the sequencing of the insert fragment of pDJH2 from genomic DNA of L. interrogans sevovar lai strain 017 and its alignment with other bacterial omp sequences. A genomic library of Leptospira interrogaans serovar lai strain 017 was constructed with the plasmid vector pUC18. A recombinant plasmid designated pJDH2 was screened from the genomic library. Inserted fragment of pDH2 is 1.9 kb by gel electrophoresis. Immunization/protection was studied in BALB/c mice model. The results showed highly significant difference between pDJH2 and pUC18 (control). Inserted fragment of pDJH2 DNA sequencing was performed by Dr Yan Zhengxin (Max-Planck-Institut for Biology. Tubingen, Germany). Insert fragment was cloned into pBluescript II KS-(stratagene) and sequenced by using AB1 (Applied Bio Systems, Model 373A). Two open reading frames of 565 and 662 nucleotides were identified. There were identifiable initiation codons, terminators, Shine-Dalgano ribosome combining site, Pribnow boxes and Sextama boxes within the 2 sequenced regions. Nucleotide sequences were analysed using Gene Work, a suit of computer program developed by Department of Biochemistry St. Jude Children's Research Hospital Memphis. U.S.A. The results of formatted alignment showed the predicted nucleotide sequence of ORF1 of the serovar lai had significant similarity with ORF2 (49.36%). L. kirschneri ompL1 (49.26%), Borrelia burgdoferi omp (48.97%), Treponema phagedenis omp (47.3%); Salmonella typhimurium ompC(46.87%), Yersinia enterocolitica ompH (46.7%), Leptospira borgpeterseni pfap (46.3%), and Serratia marcescens omp (43.3%). The close relationship of the pDJH2 ORF1 and ORF2 nucleotide sequences from Leptospira kirschneri ompL 1 is apparent. Whether the recombinant pDJH2 will prove useful for vaccine development remains to be tested.

[Subclones of fragment DNA recombinant rpDJH2 of L. interrogans serovar lai strain 017 and it's expression of high level in E. coli]

Fragment of 1.9 kb recombinant DNA of pDJH2 was linked with vectors pT7-7 and pRSETs. Then they were transformed into E. coli JM109 (DE3) respectively. Expression of subclones was achieved in E. coli JM109 (DE3) with IPTG inducement. SDS-PAGE showed that the molecular weights of products were 68kd and 23 kd respectively. The amount of production seemed to be higher than that of the outer membrane proteins of L. interrogans serovar strain 017 in nature. Immunoblotting of pDJt and pDJrB2 (both are subclones) with the specific antiserum of anti-OMP of L. interrogans serovar lai strain 017 and the experiment of initiative immuno-protection in guinea pigs showed both protein-68 kd and 23 kd might be the antigens of immuno-protection on the outer membrane of L. interrogans serovar lai strain 017.

Anesthetic and convulsant properties of aromatic compounds and cycloalkanes: implications for mechanisms of narcosis

We examined the anesthetic and convulsant properties of 16 unfluorinated to completely fluorinated aromatic compounds, having six to nine carbon atoms (e.g., benzene to 1,3,5-tris(trifluoromethyl)benzene), and four cycloalkanes (cyclopentane to cyclooctane). Benzene, fluorobenzene, toluene, p-xylene, ethylbenzene, and cyclopentane caused excitation (twitching, jerking, and hyperactivity), and three aromatic compounds (perfluorotoluene, p-difluorotoluene and 1,3,5-tris(trifluoromethyl)benzene) and three cycloalkanes (cyclohexane, cycloheptane, and cyclooctane) produced convulsions. Cyclooctane and 1,3,5-tris(trifluoromethyl)benzene were nonanesthetics. Except for nonanesthetics and perfluorotoluene (too toxic to test for anesthetic potency), all compounds produced anesthesia or decreased the minimum alveolar anesthetic concentration of desflurane. Aromatic compounds were more potent and lipid-soluble than n-alkanes (data from previous report) and cycloalkanes. All three series increasingly disobeyed the Meyer-Overton hypothesis as molecular size increased. For a particular number of carbons (e.g., cyclohexane, n-hexane, and benzene), the deviation was cycloalkanes > or = normal alkanes > aromatic compounds. These results suggest that molecular shape (including "bulkiness") and size provide limited clues to the structure of the anesthetic site of action.

[Effects of burn serum on the endothelin receptor in cardiac microvascular endothelial cells]

Cardiac microvascular endothelial cells (CMEC) were harvested and cultured. Following incubation of CMEC with normal or burn rat (30% TBSA, II degree) serum for 12 hours, respectively, the affinity and binding capacity of endothelin (ET) receptor in CMEC membranes were investigated by radioligand binding assay. The results showed that only ETB receptor was distributed in rat CMEC membranes, with a maximal binding capacity (Bmax) of 142 +/- 27 fmol/mg protein and a dissociation constant (Kd) of 119 +/- 22 pmol/L. Burn rat serum induced an increase in Bmax of ETB receptor by 68%, without changing its Kd value, demonstrating that burn rat serum up-regulated ETB receptor. These results suggest that responsiveness to ET of microvascular endothelial cells may increase following burn.

Structure of the distal human gonadotropin releasing hormone (hGnrh) gene promoter and functional analysis in Gt1-7 neuronal cells

To assess potential species-specific expression of gonadotropin releasing hormone (GnRH), the distal human (h) GnRH promoter was cloned, characterized and tested in gene transfer studies. The nucleotide sequence of approximately 3.8 kb of 5'-flanking region was determined. Homology to the rat (r) GnRH sequence was observed in the proximal promoter region between -551 h (-424 r) and the transcriptional start site and within multiple distal promoter regions. In contrast, there was little similarity in the sequences between -1131/-551 h and -1031/-424 r. A deletion panel of 5'-flanking hGnRH promoter constructs was made and tested in transient transfection assays in GnRH-producing mouse GT1-7 neuronal cells. The largest hGnRH promoter construct (-3832/+5 h) exhibited high levels of reporter activity, similar to that observed with the largest rGnRH construct (-3026/+116 r). However, in contrast to the rat gene, deletion of distal promoter sequences of the hGnRH promoter to -1971, -1131 or -551 did not result in a decrease in luciferase reporter activity. Further truncation to -350 resulted in a 3-fold decrease in luciferase activity. There was no preferential use of the putative upstream hGnRH start site in neuronal cells. DNase I protection assays showed unique protection patterns with nuclear extracts from GT1-7 and Gn10 neuronal cells and the hGnRH and rGnRH promoter fragments. These data suggest the presence of different cis-acting elements and transacting factors that mediate species-specific neuronal GnRH expression.

Occupational and Environmental Risk Factors for Asthma in Rural Communities in China

Respiratory allergens such as dust, gases/fumes, and hay smoke, which are frequently present in agricultural settings, can cause or aggravate asthma. The purpose of this study was to examine the relationships between occupational and environmental exposures and asthma in Chinese rural communities. The study population consisted of 28,946 people 15 years old or older, living in rural areas of Anhui province, China. A modified Mandarin translation of the ATS-DLD questionnaire was administered by trained interviewers to request information about exposures to specific occupational/environmental agents and respiratory disorders. In Huaining, the prevalence of wheezing was 3.8% for men; 2.1% for women; the prevalence of asthma was 1.6% for men; 1.8% for women. In Zongyang, the prevalence of wheezing was 2.7% for men; 1.9% for women; the prevalence of asthma was 1.7% for men; 1.2% for women. With control for potential confounders such as gender, age, residential area, education level, and smoking status, the pooled adjusted odds ratios (ORs) of wheezing and asthma for the group exposed to wood/hay smoke were 1.36 (95% CI: 1.14-1.61) and 1.27 (95% CI: 1.02-1.58), respectively. For coal-stove users, the pooled adjusted ORs were 1.47 (95% CI: 1.09-1.98) for wheezing and 1.51 (95% CI: 1.05-2.17) for asthma. After stratification of the subjects by dust type, the estimated ORs for wheezing were 1.58 (95% CI: 1.02-2.44) among the group exposed to inorganic dust and 3.03 (95% CI: 1.25-7.33) among the group exposed to metal dust. Asthma was not shown to be significantly associated with any specific dust type. Findings of the present study are consistent with previously reported adverse respiratory health effects related to occupational/environmental exposures to wood/hay smoke and dust, and indicate the need for further occupational disease surveillance in rural communities.

New developments in flow injection separation and preconcentration techniques for electrothermal atomic absorption spectrometry

Flow injection (FI) on-line separation and preconcentration systems for electrothermal atomic absorption spectrometry (ETAAS) are reviewed, highlighting the main developments in the field since 1990 and work achieved in the authors' laboratory. These include developments in on-line preconcentration systems based on column techniques, solvent extraction, coprecipitation and hydride sequestration. Advantages, limitations and potentials of the FI-ETAAS combination are discussed.

[16S rRNA gene PCR-SSCP analysis of the reference strains from 15 serovars (14 serogroups) of pathogenic leptospires in China]

The DNAs of reference strains from 15 serovars (14 serogroups) of pathogenic leptospires in China were amplified with 16S rRNA gene primers, and then single-strand conformation polymorphism (SSCP) of the products were analyzed in 12.5% nondenaturing mini polyacrylamide gel (containing 5% glycerol) combining with silver-staining. All products showed two bands on electrophoresis at different parameters of voltage or current and concentration of gel. It proved that serovar lai, serovar canicola, serovar pyrogenes, serovar autumnalis, serovar australis, serovar pomona, serovar linhai, serovar hebdomadis, serovar haemolytica, serovar wolffi and serovar paidjan have the identical pattern (Leptospira interrogans), while serovar javanica, serovar ballum, serovar tarassovi and serovar manhao I belong to another pattern (L. borgpetersenii). The result was consistent with the classification of genetic species by Yasuda et al (1987) and Ramadass et al (1992).

GnRH gene expression in neuronal cell lines

Little is known about the mechanisms that subserve GnRH synthesis. The recent availability of clonal populations of GnRH neurons enables us for the first time to examine the structural organization of the GnRH locus. Studies are underway to dissect the manner in which neural specific expression and developmental regulation of GnRH are programmed. These studies will complement and provide direction to future animal studies designed to better understand the control of GnRH gene expression.

[Chemical constituents of the fruits of Vitex trifolia L]

Five compounds were isolated from the fruits of Vitex trifolia and identified on the basis of spectral data and chemical methods to be rho-hydroxybenzoic acid, beta-sitosterol, beta-sitosterol-3-O-glucoside, casticin and, 3,6,7-trimethylquercetagetin. Except beta-sitosterol all of the compounds were obtained from the fruits of the plant for the first time.

Effect of angiotensin converting enzyme inhibitors on tolerance of nitroglycerin

The aim of this study was to assess whether the angiotensin-converting enzyme inhibitors captopril and enalaprilat could change the tolerance of nitroglycerin in isolated rat aortae. In aortic rings precontracted with potassium chloride, captopril (1 microM) but not enalaprilat (0.1 microM) incubation potentiated the responses to nitroglycerin. It is suggested that captopril can reduce the tolerance of nitroglycerin because it is a sulfhydryl group donor.

Protein synthesis and secretion by cultured retinal pigment epithelia

Protein synthesis and secretion by post-natal sheep and calf retinal pigment epithelial (RPE) cells was investigated following labelling of choroidal pieces, isolated RPE cells and RPE cells in tissue culture with L-[U-14C] leucine. We show that RPE cells secrete a specific set of proteins that includes retinol binding protein (RBP) and transthyretin (TTR), which are both involved in retinol transport in blood. Using a two-chambered culture system we show that protein secretion by the post-natal RPE cells occurs predominantly across the apical pole of the cells, i.e., across the surface of the cells which, in vivo, faces the retina. In agreement with results of others using foetal RPE cells (Ong, D.E., Davis, J.T., O'Day, W.T. and Bok, D. (1994) Biochemistry 33, 1835-1842) we show that RBP and, to a lesser extent, TTR are also secreted predominantly across the apical pole of the cell. We have developed a cell culture model for the RPE that may be used as an in vitro model for studying transport across the blood-retinal barrier.

Molecular and Physiological Analysis of a Thylakoid K+ Channel Protein

Transport studies identified a K+ channel protein in preparations of purified spinach (Spinacea oleracea) thylakoid membrane. This protein was solubilized from native membranes and reconstituted into artificial proteoliposomes with maintenance of functional integrity. A 33-kD thylakoid polypeptide was identified as a putative component of this thylakoid protein. This identification was made using an antibody raised against a synthetic peptide representing a highly conserved region of K+ channel proteins. K+ channel activity co-migrated with the immunoreactive 33-kD polypeptide when solubilized thylakoid membrane protein was fractionated on a Suc density gradient. The antibody was used to immunoprecipitate the 33-kD polypeptide. Physiological function of this thylakoid membrane protein was elucidated by measuring photosynthetic electron transport of thylakoid preparations in the presence and absence of a K+ channel blocker. Results indicated that K+ efflux from the thylakoid lumen through this channel protein is required for the optimization of photosynthetic capacity. The effect this protein has on photosynthetic capacity is likely due to the requirement for K+ efflux from the thylakoid lumen to charge-balance light-induced proton pumping across this membrane.

Allelic variation in the Helicobacter pylori flagellin genes flaA and flaB: its consequences for strain typing schemes and population structure

Extensive DNA sequence diversity was noted in Helicobacter pylori flagellin genes flaA and flaB. PCR amplified sequences from 49 isolates were digested with AluI, HindIII, MboI or MspI, the resultant patterns were compared between the different isolates and these used to differentiate the isolates from each other. Evidence that the extensive diversity that was found in these genes is the result of reassortment of sequences between strains in the bacterial population is presented, such that a comparatively small number of individual sequence mutations can recombine together in random combinations to form a greater number of distinct alleles. Geographical differences in the predominant patterns in the flaA alleles were also observed and could reflect regional differences either in the human host population or in the bacterial population. In view of the genetic complexity of this species, molecular typing schemes designed to identify related strains may falsely associate strains if the methods do not characterize sufficient genetic sites to exclude chance associations of genetic markers in strains which are actually not closely related to each other.

Extraskeletal osteosarcoma: a clinicopathologic study of four cases

Four cases of extraskeletal osteosarcoma which were treated at the National Cancer Center Hospital have been reviewed. There were three males and one female. The ages of the patients were 32, 48, 48 and 59 years. Three patients had a solitary tumor located in the lower leg, thigh or postirradiated abdominal wall. The remaining patient had multiple tumors in the ipsilateral thigh and buttock. The predominant histologic subtype was osteoblastic in two cases, chondroblastic in one and malignant fibrous histiocytoma-like in one. Only one patient with a subcutaneous tumor was free of disease 16 years after a wide local excision without chemotherapy. The other three patients, two having undergone inadequate initial surgery, and one with multiple tumors, developed pulmonary metastases within 24 months of their initial surgical treatment. All of them died of the pulmonary metastases eight, 36 and 63 months after their initial treatment. Postoperative intensive chemotherapy was given to two patients. Although both had developed metastases to the lung, they received resection of the metastases combined with additional chemotherapy, surviving for more than 24 months after the occurrence of their first metastases.

Specific gravities of desflurane, enflurane, halothane, isoflurane, and sevoflurane

We determined the specific gravities of presently available volatile anesthetics in order to supply a consistent quantitative basis for calibration standards. Using four 50-mL volumetric flasks, we obtained the following values at 20 degrees C: desflurane 1.4651 +/- 0.0004 g/mL (mean +/- SD); enflurane 1.5230 +/- 0.0003 g/mL; halothane 1.8680 +/- 0.0007 g/mL; isoflurane 1.5019 +/- 0.0006 g/mL; and sevoflurane 1.5203 +/- 0.0008 g/mL. Measurements made at 0 degree C, 10 degrees C, 20 degrees C, and 25 degrees C (not for desflurane at 25 degrees C) revealed a decrease in specific gravity of 0.00250 +/- 0.00014 g/mL for each degree of increase in temperature. These data bear on the issue of cost for anesthetics that are stored as liquids, but used as gases.

[The pharmacodynamics of troxipide on experimental gastric ulcers in rats]

Effects of troxipide (Ku-54) on various experimental gastric ulcers in rats were studied. Ku-54 showed a dose-dependent antiulcerous action at 100, 200 and 300 mg/kg (particularly 300 mg/kg) p.o. in water-immersion stress, pylorus ligated and acetic acid reduced rats. The effect of cimetidine (CIM) (600 mg/kg) on water-immersion stress rats was significantly higher than that of Ku-54(300 mg/kg). On the other hand, the effect of Ku-54 (300 mg/kg) was higher than that of CIM (600 mg/kg) on the pylorus ligated and acetic acid reduced groups. The antiulcerous action of Ku-54 (300 mg/kg) was not related with the content and the pH of gastric juice.