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Biomedical subjects

Z Huang

Publications and source records attributed to Z Huang.

At least 379 records · Page 21Linked to original sources
PubMed1996

[The study of insertion sequence IS2. II. Polarity effect of the mutant and DNA sequence analysis].

Insertion Sequence IS2 brought about polarity effect when it was inserted into a transcription. In study I, we found that the into polarity effects were different whether IS2 was inserted into the left side or into the right side. In this study, further research also showed that the polarity effects were very different when different IS2 was inserted into the left side. The analysis on IS2 DNA sequence showed that when the direction of IS2 ORF was the same as the transcription direction of the inserted transcription, known as a left insertion, the polarity effect was weaker. When the direction of IS2 ORF was opposite to the transcription direction of the inserted transcription, known as a right insertion, the polarity effect was stronger. When a stop codon was produced in IS2 due to base mutation, the polarity effect of a left insertion was increased.

Base Sequence↗
PubMed1996

Endovascular embolization with self-made silk segment suspension in a rabbit model.

OBJECTIVE: To evaluate the efficacy and the histologic changes caused by self-made silk segment suspension as an agent for endovascular embolization of the external carotid artery of rabbit. METHODS: Three different silk suspension were used to perform selective endovascular embolization of the external carotid artery in 21 rabbits. Postembolization changes were investigated by angiography, light and electron microscopy, and behavioral and functional examination made in various groups of rabbits. RESULTS: The vascular changes in the group of simple silk segment were limited. The intima became thinner, while the media and adventitia were intact. However, in groups of ethanol-or estrogen-soaked silk segments, there was evident destruction of all layers of the vascular wall, including the intima, the media and the adventitia. CONCLUSIONS: Estrogen- or ethanol-soaked silk suspension is ideal and reliable for endovascular embolization, with the former being more effective than the latter. The obliteration caused by the suspension of simple silk segment was due to mechanical packing and compression plus incomplete thrombosis, which is likely to result in recurrence through compensatory collateral circulation.

Animals↗
PubMed1996

Expression of cytochromes P450 in human breast tissue and tumors.

In an effort to determine which members of the cytochrome P450 (CYP) superfamily are expressed in human breast tissue and tumors, RNA-polymerase chain reaction studies have been undertaken. Detection of expressed CYP mRNAs identifies those forms of the enzyme that are capable of expression in breast tissue, and provides insight into the potential for in situ xenobiotic and therapeutic drug metabolism. CYP1A1 mRNA was present in (5/11) breast tissues and (6/13) tumors. When normal and tumor tissues were from the same individuals, higher amplification occurred in normal tissues. CYP1B1 mRNA was present in all but one tissue, and CYP2C mRNA forms were present in all of the tissues. CYP3A4 mRNA was present in (8/11) normal breast tissues and (2/13) tumor tissues, and CYP3A5 mRNA was present in (9/11) normal tissues and (2/13) tumor tissues. The expression of the CYP3A mRNA forms was not coincident, suggesting differential regulation. CYP2D6 mRNA was present in (10/11) normal breast tissue and (10/13) tumors. Two splice variants of CYP2D6 mRNA were also detected; one with a 207 bp intron spliced in was detected in all of the normal tissue samples and (11/13) tumors, whereas another (which lacks a 3'-portion of exon 6) was detected in (9/11) normal breast tissues and (7/13) tumors. Thus, examples of each of the xenobiotic-metabolizing CYP1, CYP2, and CYP3 subfamilies were detected in low levels in human normal breast tissue and tumors. The machinery for possible in situ bioactivation of xenobiotics and modification of therapeutic drugs is thus present in human breast tissue.

Breast↗
PubMed1996

Studies on high-density cultivation of Vero cells with biosilon solid microcarrier.

From eight kinds of microcarriers, Biosilon has been chosen as the most suitable microcarrier for high-density cultivation of African green monkey kidney (Vero) cells. Conditions affecting high-density cultivation were studied with a 500 ml modified Wheaton spinner flask. When cultivation with a 1.5 L CelliGen bioreactor at inoculum density of 4.9 x 10(6)/ml and perfusion volume increased from 0.20 L to 3.65 L gradually, the cell density could reach 2.05 x 10(7)/ml after 22 days of cultivation. When Vesicular Stomatitis Virus (VSV) was inoculated into the cultures of 1.21 x 10(6) ml at the some MOI (multiplicity of infection), the virus titers reached 7 log TCID50/ml and 8 log TCID50/ml, respectively.

Animals↗
PubMed1996

Endovascular embolization of intracranial aneurysms with self-made tungsten coils in a dog model.

OBJECTIVE: To evaluate the embolization effects and the long-term histologic changes, including the ultrastructure of the neoendothelium, in experimental canine aneurysms obliterated with self-made tungsten microcoil. METHODS: Twenty-eight experimental aneurysms were microsurgically created in 14 mongrel dogs by using end-to-side jungular carotid anastomosis. The aneurysms were obliterated with either self-made tungsten microcoil alone or the microcoil plus micro direct current electrocoagulation, with preservation of the parent vessel. The animals were kept in observation. 48 hours, 4 weeks, and 4 months after the embolization of the aneurysms, repeated carotid arteriography was performed to assess the potential recanalization of the aneurysms. The animals were then respectively killed and submitted for autopsy. The carotid artery and the embolized aneurysms were resected and studied with light and electron microscopy. RESULTS: A total of 14 obliterated aneurysms were completely excluded from the parent circulation by an endothelialized layer of connective tissue. The fundus of the aneurysm was completely obliterated by heavy reactive fibrous tissue surrounding the microcoils with very minimal inflammatory reaction. CONCLUSIONS: Tungsten microcoils are a relatively ideal embolic material at present for endovascular treatment of aneurysms. Microcoils plus micro direct current electrocoagulation yield more reliable, accurate, and safer embolic effects than microcoils alone for the obliteration of aneurysms.

Animals↗
PubMed1996

Antitumor activity of thevetoside in vitro.

OBJECTIVE: To study the effects of thevetoside (TS), a cardiac glycoside, and an inhibitor of Na+, K(+)-ATPase, on tumor cells cultured in vitro. METHODS: The cytotoxic effects of TS on tumor cells were determined by trypan blue dye exclusion, neutral red vital staining and clonogenic assay. The time-effect relationship and growth inhibition of tumor cells by TS were assayed with trypan blue exclusion method. RESULTS: TS at low doses (0.005-0.1 mg.L-1), with dose dependence, was able to kill SMMC-7721, SGC-7901 and HeLa cells. IC50 values for SMMC-7721, SGC-7901 and HeLa cells were 0.007, 0.011 and 0.018 mg.L-1 by trypan blue dye exclusion test and 0.016, 0.055 and 0.078 mg.L-1 by neutral red vital staining test. TS inhibited the clonal forming rate of SMMC-7721 and SGC-7901 significantly with IC50 values of 0.021 and 0.036 mg.L-1, respectively. Only when the cells were continuously treated with TS for more than 8 hours, the drug-induced cell lethality could be displayed and strengthened quickly. The growth of tumor cells was notably inhibited after they were exposed to 0.1 microgram/ml of TS for 12 hours. All the experimental results of antitumor activity in vitro showed that SMMC-7721 was most sensitive to TS among the three kinds of tumor cells. CONCLUSIONS: TS has cytotoxic action on tumor cells cultured in vitro and this lethal effect must have an action process, in which tumor cells are not dead but suffer from deadly injury and lost the capability of unlimited proliferation.

Adenocarcinoma↗
PubMed1996

[The PCR amplification, cloning, sequencing, expression in E. coli of gene encoding endoflagella subunit protein (fla B) from Leptospira interrogans serovar lai].

A pair of oligonucleotide primers were designed by ourselves to amplify the endoflagella gene of L. interrogans serovar lai. A fragment about 840 bp was generated with PCR and inserted into plasmid pUC8 after the fragment and pUC8 were digested respectively with Bam HI and Pst I. A recombinant plasmid (designated as pLF1) was obtained. SDS-PAGE analysis indicated that a 33 kd was expressed in E. coli JM103 harboring pLF1 and the expression level of the protein was 11% of total bacterial soluble proteins. Western blot analysis showed that the protein band could be recognized by the antiserum against the endoflagella (Axiall filament) of Leptospira interrogans serovar lai. Nucleotide seguence data showed an open reading frame encoding 282 aminoacids residues, corresponding to a protein of molecular weight 33.6 kd. The G + C content of endoflagella subunit protein gene was 48 mol%. Therefore, the G + C content of the leptospiral fla B Gene is significantly higher than the reported 39 mol% G + C content of leptospiral genome of L.interrogans serovar lai but similar to the G + C of the Treponema pallidum genome. Comparison of the deduced endoflagellar subunit protein (fla B) amino acid sequence with flagellins from other bacteria revealed a high level of identity with the Treponema pallidum fla B proteins. Immunization/protection experiment was performed on the model of BALB/c mice and showed that the survival rate in the group JM103-pLF1 was higher than that in the group JM103-pUC8, but statistically the difference between them was significant (P < 0.05) and pLF1 did not induce significant levels of agglutinating antibodies against L.interrogans serovar lai.

Amino Acid Sequence↗
PubMed1996

[Effects of smoking on lung function in populations of Beijing and Guangzhou].

OBJECTIVE: To analyse the relationship between cigarette smoking and lung function in populations of Beijing and Guangzhou. METHODS: Complete lung function and smoking habit data were recruited from 7983 men and women aged 35-59 in or around Beijing and Guangzhou. Comparisons were made between smokers and never smokers. RESULTS: The mean values of FEV1/H2, FEF/H2 and FEV1/FVC are all lower in smokers than in never smokers for male smokers, the observed mean value of FEV1/H2 for each age group in smaller than the respective predicted value, and its descending trend with aging is more obvious than the predicted value when re-examination after 2-4 years; furthermore, smokers had higher prevalences of respiratory symptom and COPD. CONCLUSION: Cigarette smoking is harmful to lung function.

Adult↗
PubMed1996

[Effects of Radix angelicae sinensis on systemic and portal hemodynamics in cirrhotics with portal hypertension].

The present study investigated effects of Radix angelicae sinensis (RAS) on systemic and portal hemodynamics in cirrhotic patients with portal hypertension. The results demonstrated that, after intravenous injection of the agent (20 mg.kg-1.min-1), systemic hemodynamics (heart rate, mean arterial pressure, inferior vena cava pressure, systemic vascular resistance, cardiac output, cardiac index) remained unchanged, but portal hemodynamics signicantly improved, wedged hepatic venous pressure (WHVP) (3.79 +/- 0.76 kPa vs 2.72 +/- 0.89 kPa, P < 0.01) and hepatic venous pressure gradient (HVPG) (2.88 +/- 0.73 kPa vs 1.78 +/- 0.68 kPa, P < 0.01) reduced by 29.40 and 35.78 percent respectively. However, anti-portal hypertensive effect of RAS was inverse proportion to the basical level of WHVP or HVPG in the cirrhotics. We conclude that RAS can effectively decrease portal pressure and yet gives no influence on systemic hemodynamics in the cirrhotic patients with portal hypertension.

Adult↗
PubMed1996

[The cellular immunologic status of the laryngeal cancer patients].

To observe the cellular immunologic status of the laryngeal cancer patients 70 laryngeal cancer patients were examined with immunohistochemical method. The peripheral blood T lymphocyte subsets were detected and local tumor infiltrative T lymphocytes were observed. The results showed that the cellular immunologic function of laryngeal cancer patients was lower than that of the healthy persons and the function of late staged patients was lower than that of the early staged patients. The pattern of changes of these two observations was of the same trend. The clinical significance of the examinations was discussed.

Adult↗
PubMed1996

[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.

Animals↗
PubMed1996

[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.

Animals↗
PubMed1996

[A cohort study on the relationship between standardized mortality of pulmonary heart disease and smoking].

We explored the relationship between the standardized mortality of pulmonary heart disease (PHD) and smoking at Shifang county through a five-year follow-up study of 29,498 farmers over 35 years old. The death ratio of PHD was 30.35%, which stood first in all causes of death. The mortality of PHD for cigar/cigarette smokers regardless of sex was not significantly different from that for nonsmokers (P > 0.05). The RR was 1 or so. The analysis of data stratified by age showed that the specific mortality increased with age in spite of some inequalities smoking; the RR of PHD for cigar/cigarette smokers in all age groups were 1 or so revealing no significant differences (P > 0.05). However, the standardized mortality of PHD increased with the accumulated amount of smoking. The relationship between the mortality of PHD and short-term smoking with small dose was not significant (P > 0.05), but when the accumulated amount reached certain level, i.e. the smoker consumed cigar more than 270 kg or consumed cigarette more than 20,000 packs, the relationship between the behavior of cigar/cigarette smoking and the mortality of PHD became apparent. The RRs were 1.40-3.94 and the ARs 171-1610 per 100,000 person years (P < 0.05-0.01).

Adult↗
PubMed1996

Clinical research on acute hemoptysis treated with kexue ning.

The efficacy of Kexue Ning (stopping hemoptysis) in the treatment of acute hemoptysis, and its comparison with that of the control group (treated with western medicine) are reported in this paper. The results showed that both the time for cessation of hemoptysis and the cure rate were better in the therapeutic group than in the control group. In addition, marked improvement in blood rheology after treatment was also found in the therapeutic group, but not in the control group.

Acute Disease↗
PubMed1996

[Helicobacter pylori infection and gastric mucosa-associated lymphoid tissue hyperplasia].

The association of Helicobacter pylori (Hp) infection with mucosa-associated lymphoid tissue (MALT) hyperplasia in gastric mucosa was investigated. The results showed that the incidence of Hp infection increased as the degree of the mucosal injury was aggravated, but the prevalence of lymphoid follicles in the mucosa with atrophic antritis was much more than in the mucosa without the atrophic and the frequency of detecting Hp and intestinal metaplasia in the mucosa with lymphoid follicles significantly increased, as compared with the mucosa without it. These findings suggest that gastric MALT hyperplasia induced by Hp infection may lead to destruction of gastric glands through hypersensitivity.

Adolescent↗