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Biomedical subjects

H Wang

Publications and source records attributed to H Wang.

At least 1,513 records · Page 84Linked to original sources
PubMed1998

[Detection of hepatitis C virus and hepatitis G virus RNA by multiplex reverse transcription-polymerase chain reaction and microtiter plate reverse hybridization].

Multiplex reverse transcription-polymerase chain reaction for the simultaneous detection of HCV and HGV RNA has been established, in which primers were deduced from high conservative region of HCV and HGV and PCR amplicons were detected by microtiter plate reverse hybridization with HCV or HGV specific probe. Sequence analyses showed that amplicons of HCV were 93.1%-94.1% and 92.5%-93.7% of nucleotide homology compared with Takamizawa and Choo, and amplicons of HGV were 90.7%-92.5%, 92.0%-92.1% and 94.3%-94.5% of nucleotide homology with Simons, Linnen and Chang. The detective sensitivity was 100 times over that of electrophoretic assay with single amplification. CVs of HCV and HGV were 8.9% and 9.8%, respectively, and the optimal concentration of NaOH for hybridization was 0.1-0.15 mol/L. The optimal time for hybridization was 30-50 minutes. The results of detection with multiplex PCR showed the presence of infection with HCV or HGV alone and coinfection with both % them.

DNA Probes↗
PubMed1998

[The coinfection of hepatitis C virus with hepatitis G virus and its reaction to interferon treatment].

HGV RNA was detected in 60 cases of hepatitis C patients and its positive rate was 23.3%, also the HGV infection was more frequent in chronic hepatitis C patients than in acute hepatitis C, and was only detected in hepatitis C patients who experienced transfusion of blood or blood products. These results indicated that transfusion was the main transmission route for HGV infection. HGV infection could shorten the incubation period of post-transfusion hepatitis C, but it would not worsen the status of the disease. The coinfection of HCV and HGV did not interfere the effect of interferon treatment on hepatitis C patients either in normalization of ALT or the elimination of HCV.

Adult↗
PubMed1998

[Transient response in electric measurement of human auricular point].

This is an experiment on the measuring E approximately t and R approximately t for human auricular point, which shows there is a transient response of electric potential E(t) and voltage drop U(t) when t < 2 tau and there is at intervals change with the time after 2 tau about R(t) and E(t). We have obtained a response function of the E(t) and U(t) by the circuit analysis. The parameter of the transient character is relaxation time tau, tau approximately RC. The mathematical model is in correspondence with the experimental result of the auricular point and TPM simulation. It indicates that the character changing with the time should be extracted after 2 tau. This experiment is of importance to understanding the electric character of the otopoint.

Acupuncture Points↗
PubMed1998

[Transient response in electric measurement of human auricular point].

This is an experiment on the measuring E-t and R-t for human auricular point, which shows there is a transient response of electric potential E(t) and voltage drop U(t) when t < 2 tau and there is at intervals change with the time after 2 tau about R(t) and E(t). We have obtained a response function of the E(t) and U(t) by the circuit analysis. The parameter of the transient character is relaxation time tau,tau approximately RC. The mathematical model is in correspondence with the experimental result of the auricular point and TPM simulation. It indicates that the character changing with the time should be extracted after 2 tau. This experiment is of importance to understanding the electric character of the otopoint.

Acupuncture Points↗
PubMed1998

[The time-frequency analysis of the heart sound].

The Wigner-Ville distribution, the Choi-Williams distribution, and cone-kernel distribution are three time-frequency distributions. We compared the interference attenuation and time-frequency concentration properties of the three TFDs. The properties were then further investigated by studying the results obtained for a chirp signal. We analysed the heart sounds, nonstationary signals, with the three TFDs. The results indicate that the time-frequency signal analysis methods have high time-frequency resolution. The time-frequency signal analysis techniques may be helpful in unveiling the complex mechanisms of heart sound generation and be used in medical research and clinical diagnosis.

Adult↗
PubMed1998

[Isolation and identification of Agrobacterium spp. from cherry crown galls and their sensitivities to agrocin 84].

Crown galls were sampled from cherry yards of Shandong, Hebei, and Liaoning provinces. 46 pathogenic strains were isolated. Physiological and biochemical tests revealed that 4 strains were Agrobacterium tumefaciens(bio. 1) and that the other 42 strains were A. rhizogenes (bio. 2), according to the classifications and nomenclatures of the genus Agrobacterium and the species revised by Sawada et al and Bouzar. The Ti plasmids of all strains were nopaline type. All strains were sensitive to agrocin 84, which suggested that crown gall disease of cherry could be controlled by K84 strain.

Adenine Nucleotides↗
PubMed1998

[Establishment of hybridoma secreting anti-mycobacteria monoclonal antibody by using electrofusion technique].

By using the electrofusion technique, the fusion of NS1 myeloma cells with spleen cells of BALB/c mouse immunized with five species of mycobacteria was carried out. With the optimal electrofusion conditions, we obtained a high fusion efficiency of 1.75 hybrid cell clones per 10(5) spleen cells. ELISA was used for screening secreting antimycobacteria McAb hybrid cells. After cloning, 22 stable hybrid cells lines were selected, and 8 of them had been studied.

Animals↗
PubMed1998

[Observations of characteristics of the mechanisms of biological oxidation of cell wall-deficient bacteria].

The L-forms were induced from Staphylococcus aureus, Escherichia coli and Bacillus cereus by beta-lactam antibiotics and then observations on the properties of oxygen requirement, sugar fermentation and sensitive to cyanide of the L-forms were done. The results were shown that the L-forms derived from the obligate aerobe or the facultative anaerobe did not ferment sugars and were highly oxygen-dependent and more sensitive to cyanide than their parent bacteria. The metabolic activities which were same as the parent bacteria of the L-forms would return after the L-forms reverted to the typical bacteria forms. It was possible that the changes of biological oxidation mechanism were due to the deficiency of the cell wall which led to loss of the periplasmic space or the membrane-wall interlayer so that the enzymes for fermentation existed in the space could not be hold.

Bacillus cereus↗
PubMed1998

[The use of isoparametric element of arbitrary hexahedron for solving 3-D thoracic potential distribution].

Isoparametric element of arbitrary hexahedron plays an important role in finite element analysis. This article devotes itself to establishment of mathematical model and combination of derivative of shape function of such element type. In addition, the article also discusses the usage of isoparametric element for solving 3-D thoracic potential distribution in electrical field.

Algorithms↗
PubMed1998

[Preliminary study on radiant spectra of the leaves of paddy and upland rice].

The characteristics of the radiant spectra (i.e. absorption, reflectance and transmission) of leaves of paddy and upland rice were studied. The experiment proves that the characteristics of the radiant spectra of the seedling leaves of paddy and upland rice is basically the same in the range of 200-800nm, and their chlorophyll content of the leaves is also quite near (the average values for paddy and upland rice are 4.25mg/g and 4.28mg/g, respectively). However, the absorption of the flag leaves of upland rice is higher and the transmission is lower compared to paddy rice in the heading-flowering period, while the reflectance is almost the same except for 550nm. The chlorophyll content in the leaves of upland rice is approximate twice as that of paddy rice (the average values of paddy and upland rice are 0.86mg/g and 1.86mg/g, respectively).

Absorption↗
PubMed1998

[Detection of radical anion of nitrobenzene in situ on palladium electrode in different solvent].

By means of a highly sensitive electrolytic cell installed in the ESR cavity, radical anion of nitrobenzene in the process of nitrobenzene electroreduction on palladium electrode in different solvent is dectected by flowing electrolytic system. The results show that in different solvent the discrimination of the ESR spectra are different, the solvent has an effect on nitrobenzene radical anion. The nitrobenzene electroreduction on Pd electrode must produce radical anion as an intermediate.

English Abstract↗
PubMed1998

Differential effects of intrathecally administered delta and mu opioid receptor agonists on formalin-evoked nociception and on the expression of Fos-like immunoreactivity in the spinal cord of the rat.

This study examined the effects of intrathecally (i.t.) administered mu and delta opioid receptor agonists on the flinching behavior and the expression of Fos-like immunoreactivity (Fos-LI) in the spinal cord elicited by s.c. injection of 5% formalin in one hindpaw of the rat. Intrathecal pretreatment with either the delta-1 opioid receptor agonist [D-Pen2,5]enkephalin (DPDPE) or the delta-2 opioid receptor agonist [D-Ala2,Glu4]deltorphin (DELT) produced a dose-dependent inhibition of flinching behavior in phase 1 and phase 2 that was antagonized by coadministration of the delta-1 opioid receptor antagonist 7-benzylidinenaltrexone or the delta-2 opioid receptor antagonist Naltriben, respectively. Although i.t. pretreatment with 60 micrograms of DPDPE produced a small decrease in the numbers of Fos-LI neurons in laminae I, IIi and IIo, as well as laminae V and VI and laminae VII-X, i.t. pretreatment with 30 micrograms of DELT did not decrease the number of Fos-LI neurons in any region of the spinal cord. In contrast, i.t. pretreatment with an equieffective dose of the mu opioid receptor agonist [D-Ala2,NMePhe4,Gly-ol5]enkephalin (DAMGO) not only significantly decreased the number of flinches in phase 1 and phase 2, but also nearly completely prevented the expression of Fos-LI in all regions of the spinal cord. These effects were antagonized by pretreatment with the mu opioid receptor antagonist D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Phe-Thr-NH2. The efficacy of i.t. administered DAMGO suggests that a direct spinal action contributes to the inhibition of noxious stimulus-evoked Fos-LI in the spinal cord produced by systemically administered mu opioid receptor agonists such as morphine. The relative lack of effect of DPDPE or DELT suggests that delta opioid receptors do not modulate the early-immediate gene c-fos. Alternatively, because delta opioid receptor agonists inhibit synaptic transmission in the spinal cord by predominantly presynaptic mechanisms and do not hyperpolarize dorsal horn neurons, the excitatory inputs that persist in the presence of these agonists may be sufficient to activate the c-fos gene. Taken together, these results provide new evidence, at the level of a "third messenger," that the antinociception produced by i.t. administration of delta and mu opioid receptor agonists is mediated by different mechanisms.

Analgesics, Opioid↗
PubMed1998

Prevention of stroke and preservation of the functions of cerebral arteries by treatment with perindopril in stroke-prone spontaneously hypertensive rats.

The aim of this study was to determine whether the prevention of stroke with perindopril treatment in stroke-prone spontaneously hypertensive rats (SHRSP) is associated with the preservation of the myogenic properties of the cerebral arteries. After weaning at 4 weeks of age, male SHRSP were fed a Japanese-style rat diet with high salt to induce stroke development. Treatment with perindopril was given by gavage every morning beginning at 6 weeks of age. There were three experimental groups: two groups treated with 4 mg.kg-1.day-1 perindopril for different durations (8 or 12 weeks) and one control group consisting of littermates given distilled water. All the control animals developed stroke and died within 14 weeks of age, and myogenic response of the middle cerebral arteries (MCA) to pressure increase was lost in these animals. In contrast, all the treated SHRSP survived during the treatment period, and myogenic response of the MCA was preserved. After withdrawal of the treatment, SHRSP treated for a longer period (12 weeks) also survived longer than those treated for a shorter period (8 weeks). The subsequent development of stroke and death following treatment withdrawal after 8 or 12 weeks of treatment was associated with the loss of pressure-dependent constriction in MCA. A longer treatment duration also increased the stiffness of the MCA, MCA from SHRSP after 12 weeks of treatment had smaller external and lumen diameters, and thicker walls than those from the 8-week treatment group. In a separate study, we found that treatment of SHRSP with 1 or 4 mg.kg-1.day-1 of perindopril for 24 weeks beginning at 6 weeks of age also protected them against death related to stroke, because these rats survived up to 43 weeks of age, when the experiment was terminated. We conclude that there is an association between the absence of myogenic response in cerebral arteries and stroke development in SHRSP. Perindopril treatment preserves the myogenic response of MCA in SHRSP and prevents the stroke development in these animals. A prolonged treatment could increase the survival of SHRSP through a remodelling of the MCA and increasing the stiffness of the cerebral arteries.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1998

Expression of adrenomedullin in portal hypertensive gastric mucosa of rats.

We examined the expression and localization of adrenomedullin (AM) mRNA, AM receptor (AM-R) mRNA and AM protein in normal and portal hypertensive (PHT) rat gastric mucosa. Methods included competitive reverse transcription-polymerase chain reaction (RT/PCR), in situ hybridization and Western blot analysis. Both AM mRNA and AM-R mRNA were strongly expressed not only in normal rat gastric mucosa but also PHT rat gastric mucosa. While total AM and AM-R mRNA abundance was similar in both normal and PHT stomachs, in the superficial mucosa-where major defense mechanisms are located-their expression was significantly reduced in PHT rats by 33% (AM mRNA) and 25% (AM-R mRNA) (both p .0.05). AM protein was also expressed similarly in both normal and PHT gastric mucosa. We conclude that AM and its receptor play a role in regulation of gastric mucosal microcirculation and thus gastric mucosal defense.

Adrenomedullin↗
PubMed1998

[Gene diagnosis of 10 Chinese families with adult polycystic kidney disease from Guangxi region].

OBJECTIVE: To study presymptomatic gene diagnosis in adult polycystic kidney disease (APKD). METHODS: Linkage analysis and haplotype characterization were carried out in 10 unrelated Chinese APKD families from Guangxi region, including 97 individuals and 29 affected members. Members of these families were ultrasonographically examined. Linkage to PKD1 was investigated in all families with four microsatellite markers(SM7, CW2, AC2.5, and KG8). These flanking markers were amplified by PCR. RESULTS: The families were fully informative for gene diagnosis and no evidence of genetic heterogeneity was found. DNA analysis predicted 7 asymptomatic individuals(by 28 years old) as being affected, although they all presented negative ultrasonographs. CONCLUSION: Linkage analysis is still an important way in APKD presymptomatic gene diagnosis.

Adult↗
PubMed1998

[Construction and application of retroviral vector carrying green fluorescent protein].

OBJECTIVE: To construct retroviral vector carrying rapidly selective marker. METHODS: The recombination retroviral vector GCGFPPXSN was constructed by cloning the green fluorescent protein (GFP) cDNA into the retroviral vector containing putative internal ribosome entry sites GCXPXSN and transferred in ecotropic packaging cell line PE501 by electroporation method. The supernatants of the PE501GCGFPPXSN were used to infect the amphotropic packaging cell line PA317. The G418 resistant clones were selected in 4 weeks and were detectable by fluorescence microscopy or by fluorescence-activated cell sorting(FACS). RESULTS: A recombination retroviral vector GCGFPPXSN carrying rapidly selective marker GFP was constructed. GFP expression in packaging cell line PA317-GCGFPPXSN transferred by GCGFPPXSN was detected by fluorescence microscopy of FACS. PA317-GCGFPPXSN grew to a titer of 1.2 x 10(5) cpu/ml. By cocultivating retroviral vector producing cells and T lymphocytes, expression of GFP was observed in T lymphocytes 2 days after the end of the cocultivation. T lymphocytes expressing GFP were separated. CONCLUSION: The mammalian cell can be efficient gene transfected by retroviral vector carrying GFP. The use of GFP for cell marking represents an important advantage over conventional strategies which typically involve the use of neomycin resistance. GFP, in fact, allows a rapid in vitro selection of transduced cell by FACS. The selection requires only two-day culture with this retroviral vector, compared with 10-14 day culture with a classical retroviral vector.

Cell Line↗
PubMed1998

Mutagenicity of urine from individuals exposed to LPG combustion products.

The mutagenicity of urine from individuals exposed to the combustion products of liquefied petroleum gas (LPG) was detected with Salmonella typhimurium TA98 and its newly developed derivatives YG1021 (nitroreductase overproducing) and YG1024 (O-acetyltransferase overproducing). The detection showed significantly increased mutagenicity for the two YG strains and increased positive rates for all three strains in the presence of both rat liver S9 and beta-glucuronidase. Further analysis demonstrated that urine samples taken from smoking and non-smoking exposed individuals exhibited significantly higher mutagenic potency (revertants/10 microliters urine concentrate) than their corresponding controls. These results indicate that the increased urine mutagenicity is caused by the exposure to LPG combustion products or smoking. The mutagenic potency of urine samples of all exposed individuals tested with YG1024 was found to be about 7 times higher than with TA98. The difference in mutagenic potency was smaller for the same samples when comparison was made between YG1021 and TA98. This suggests that the mutagenic compounds present in the urine samples contain mainly aromatic compounds as glucuronide conjugates. Our results demonstrate that YG1024 is more sensitive than TA98 in detecting the mutagenicity of these samples. In addition, no significant difference in the mutagenic potency between the 'pure' exposed (non-smokers') and the 'pure' smokers' (unexposed) samples was found in all three tester strains. This might mean that the exposure extent of mutagens/carcinogens in LPG combustion products for exposed individuals roughly corresponds to the smoking level of smokers who smoke 20-40 cigarettes per day. Furthermore, the results also suggest that synergism might exist in the mutagenic effects of exposure to LPG combustion products and cigarette smoking.

Adult↗