Biomedical subjects
Publications and source records attributed to Z Fang.
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.
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).
Using the methods of in situ hybridization (ISHH), ISHH combined with immunocytochemistry ABC and image processing, somatostatin (SOM) mRNA level and coexistence of SOM mRNA and 5-HT in the nucleus raphe dorsalis (RD) of rat were studied in the normal group, noxious stimulation group, simple electroacupuncture group and electroacupuncture analgesia group (EA). A number of oval and fusiform cells with a weak to moderate hybridization signals were mostly distributed in dorsomedial subnucleus of RD and concentrated on rostral part. An increase of SOM mRNA positive cells could be seen in noxious stimulation group and simple electroacupuncture group comparing with the normal group. In EA group the number of SOM mRNA positive cells increased more than any other groups. A few SOM mRNA and 5-HT doubled cells could be seen in RD in the normal group. Most of the doubled cells were distributed in ventromedial, lateral subnuclei of RD. Comparing with the normal group, doubled cells increased in noxious and simple electroacupuncture group and increased significantly in EA group. The results suggest: (1) SOM takes part in modulation of pain. (2) SOM plays a role in EA. (3) Coexistence of SOM mRNA and 5-HT-in RD suggests that SOM and 5 HT interact synergically in EA.
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.
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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.
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.
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.
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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.
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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.
The function of red nucleus (RN) was important in motor control. This work was to study whether the RN influenced the effect of EA and the somatosensory afferent system. C-responses of spinal dorsal horn neurons (SDHN) were recorded as nociceptive responses. Electrical stimulation of RN could intensify the inhibitory effect of EA and inhibit nociptive response of SDHN. Naloxone (NX) could completely block that inhibition of RN. The result inferred that the RN can modulate both of somatomotion and somatosense. The endogenous opiate system is involved in the somatosensory modulation of RN.
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.
Twenty spontaneous hypertensive rats (SHR) with systolic blood pressure (SBP) >or= 20 kPa were chosen and divided randomly into two groups (acupuncture group and control group). The former was acupunctured on bilateral Quchi (L1 11), Zusanli (ST 36). Another 46 immature SHRs which were about 7-week-old with SBP ranged from 16 kPa to 20 kPa were given 10% high molecular weight dextran (HMWD) or normal saline by intervention respectively. The results showed: 1. After three course of acupuncture, SHRs' SBP dropped remarkably from 25.493 +/- 0.73 kPa to 19.547 +/- 0.555 kPa (P < 0.01); 2. After three courses of acupuncture, NE and 5-HT contents in plasma were lowered (P < 0.05, < 0.01) and DA content in plasma was increased (P < 0.05) compared with that in the control group. 3. After three course of acupuncture, NE content in brainstem, hypothalamus, cerebral cortex increased (P < 0.005-0.01) and DA content in brainstem, cerebral cortex increased remarkably (P < 0.005-0.01) compared with that in the control group. 5-HT content in brainstem, hypothalamus, and cerebral cortex increased obviously compared with that in the control group. 4. After 1 or 2 hours of intervention of 10% HMWD to immature SHR, the whole blood viscosity and blood pressure rise remarkably compared with normal saline group. The experiment implies that the mechanism of lowering the blood pressure of SHR by acupuncture lies in that it can adjust NE, DA and 5-HT contents in plasma and central nervous system to adjust the activity of sympathetic, reduce whole blood viscosity etc.
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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.
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