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Biomedical subjects

X Meng

Publications and source records attributed to X Meng.

At least 235 records · Page 13Linked to original sources
PubMed1993

Cloning of chicken hsp90 beta: the only vertebrate hsp90 insensitive to heat shock.

The cloning of chicken hsp90 beta, reported here, supports the hypothesis that the hsp90 alpha and beta genes are the result of a gene duplication event that occurred at the time of the emergence of vertebrates. Avian hsp90 beta mRNA is not inducible by thermal stress contrary to the mouse and human hsp90 alpha and beta mRNAs. Moreover, hsp90 beta mRNA level is not increased by mitogenic stimuli, like serum or insulin, which induce hsp90 alpha mRNA. Different functions and regulations of hsp90 alpha and beta will be probably more easily understood in the avian species than in higher vertebrates.

Amino Acid Sequence↗
PubMed1993

[Recording intracellular potentials of viscero-nociceptive neurons in posterior group of thalamic nuclei (PO) and their labeling with HRP intracellularly in cats].

Intracellular potentials (ICP) of the neurons in PO evoked by stimulating greater splanchnic nerve (GSN) were recorded in 42 cats. The resting potentials and action potentials induced by stimulating GSN were 53.74 +/- 11.68 mV and 29.44 +/- 9.22 mV respectively. Owing to intensity of the stimulation we can record EPSP and single spike or polyspikes on it. The action potentials derived from stimulating GSN (related action potentials) were inhibited by injection of morphine intravenously. On the basis of recording ICP, we also labeled 2 related neurons with stimulation of GSN and 2 unrelated ones. Differences between two kinds of the neurons were compared preliminarily. The ICP of the related neuron with stimulating GSN were inhibited by stimulating Amygdala too. Factors influencing amplitude of action potential in intracellular recording, criteria of determining nociceptive neuron and inhibition derived from stimulating Amygdala were also discussed.

Action Potentials↗
PubMed1993

[Experimental study on intratumoral injection with hydroxyapatite bioceramics and adriamycin in implanted hepatoma in mice].

Hydroxyapatite (HA) bioceramics is a biomaterial used in orthopedic area. We observed its anticancer effect in experimental hepatoma-22 (H22) in mice. BALB/c mice implanted with H22 were grouped into I, II, III and IV. Intratumoral injections were given as follows: (I) HA 0.1 g and ADM 0.1 mg n = 28; (II) HA 0.1 g n = 16; (III) ADM 0.1 mg n = 16; (IV) untreated n = 20. The tumor regression rates of the groups I, II and III were 65.9%, 41.9% and 51.1%, respectively. The mean survivals of groups I, II, III and IV were 32, 22, 26 and 18 days. Six mice of group I were alive more than 50 days before being killed, in which 4 tumor samples showed that no residual tumor cells could be seen under microscope. The possible mechanism of HA anti-cancer action is: (1) the dissolved matter of HA, glycoprotein and microfibril around the tumor cells may disturb the metabolism of cancer; (2) fibrocalcific process restricts the tumor growth; (3) immunoenhancement action (4) as a drug-release system HA is a hopeful agent of intratumoral injection for treatment of cancer.

Animals↗
PubMed1992

Intracellular potentials of visceronociceptive neurons in posterior group of thalamic nuclei and its labeling with HRP intracellularly in cat.

The intracellular potentials (ICP) of 42 visceronociceptive neurons related to stimulating greater splanchnic nerve (SPL) in Posterior group of thalamic nuclei (PO) were investigated. We analyzed the electrophysiological features, such as amplitude of resting potentials and action potentials of the neurons. Following acquisition of electrophysiological data, (HRP) was injected into 3 neurons, whose responses were inducted by stimulating SPL (related neurons) and able to be inhibited by morphine intravenously. Two neurons revealing spontaneous discharges but are not able to evoke response by stimulating SPL (non-related neurons), also were stained by HRP. Two kinds of neurons, related and non-related ones, display different dendrite branching patterns.

Action Potentials↗
PubMed1992

[Pathological and clinical study on 80 cases of liver disease in pregnancy].

Ninety-seven cases of liver disease in pregnancy confirmed by pathological examination were studied. The results showed that in addition to virus hepatitis (58.8%), which was the leading cause, there were quite a proportion of other liver diseases. Among these acute fatty liver of pregnancy accounted for 18.6%, intrahepatic cholestasis of pregnancy were 16.5%. The causes of misdiagnosis and the bases for differential diagnosis were discussed. It was considered that early pathological examination of liver and other morphological study were important in diagnosis of liver diseases in pregnancy.

Adult↗
PubMed1992

[Role of Langerhans' cells against cervical human papilloma virus infection and development of cervical carcinoma].

Human papilloma virus (HPV) in the development of cervicitis and cervical carcinoma, and the role of Langerhans' cells (LC) against cervical HPV infection and development of cervical carcinoma were studied by immunohistochemistry and by DNA molecular hybridization techniques for the HPV type 6, 11, 16 and 18 DNA sequences. The total results were analysed and correlated. It was found that the positive rate of HPV type 6 and 11 in cervicitis was significantly higher than that in cervical carcinoma (P less than 0.01), and the positive rate of HPV type 16 and 18 was higher than that in cervicitis, but only the difference of HPV type 16 positive rate reaches significance level (P less than 0.01). The results also showed that the mean density of S100 + LC in cervical carcinoma specimens was significantly higher than that in cervicitis specimens (P less than 0.01). The results indicate that HPV type 6 and 11 are closely related with cervicitis, and HPV type 16 and 18 are closely related with the development of cervical carcinoma. LC plays an important role in attacking HPV infection of the cervix and the development of cervical carcinoma. The results also suggest that S100 + LC and OKT6 + LC are different subtypes of LC, and S100 + LC is an activated-subtype which plays a major role of immunosurveillance function.

Carcinoma, Squamous Cell↗
PubMed1992

[Study on the serological typing of patients with epidemic hemorrhagic fever (EHF) and host animals in Junan County, Shangdong Province].

Using hemagglutination inhibition test (HI), we confirmed that Junan County is an endemic area of both EHF of R. norvegicus and A. agrarius, which indicated that the main host animals were R. norvegicus and A. agrarius in the area. Remarkable difference was shown between the infectious rates of pigs from the endemic area and that of pigs from the nonendemic area, which suggested that pigs could play certain roles in the transmission of EHF. We also proved that the main transmission mode of EHF virus in rats was horizontal transmission, and vertical transmission in rats also existed.

Animals↗
PubMed1992

[Estrogen and progesterone receptors in laryngeal carcinoma].

The existence of hormone receptors on or within neoplastic tissue has potential diagnostic, therapeutic, and prognostic importance. It has now been demonstrated in many reports that cancers of the breast and prostate often express hormone receptors and can be controlled by hormone manipulation. The fact that larynx is a target organ for androgenic steroids has long been known. The question of whether laryngeal carcinoma expresses hormone receptors has been a matter of interest. We adopted the fluorescent hormone conjugate method to measure the estrogen receptor (ER) and progesterone receptor (PR) in 25 patients with laryngeal cancer. Our findings indicated that in 25 samples of laryngeal cancer 48% were ER positive, and 68% were PR positive. Cells of the laryngeal cancer not only contain ER and PR but also have relationship between the presence of receptors and the degree of histologic differentiation. Low differentiated cancers are inclinable to contain low level receptors. From this initial survey it appears that the hormone receptors could play an important role in the cancer of larynx. The presence of receptors in some laryngeal carcinoma implicates that these tumors are possibly hormone sensitive.

Adult↗
PubMed1992

[Pharmacological study on Veronicastrum sibiricum (L.) Pennell].

Six compounds were isolated from Veronicastrum sibiricum and identified as D-mannitol, beta-sitosterol, daucosterine, 3-0-acetyloleanolic acid, 3, 4-dimethoxy cinnamic acid and isoferulic acid. Pharmacological experiment has shown that isoferulic acid is anti-inflammatory and analgesic; 3-0-acetyloleanolic acid is anti-inflammatory; mannitol is analgesic, 3, 4-dimethoxy is also anti-inflammatory and analgesic.

Analgesics↗
PubMed1991

Quantification of in-vitro post-antibiotic effect based on the mean recovery-time. I: Theoretical perspectives and a practical procedure.

An empirical description of the post-antibiotic effect has been previously proposed on the basis of the time required for the bacterial density to increase by one log10 following antimicrobial exposure. In this study, a set of theoretical perspectives are established and the post-antibiotic effect quantitatively defined based on the mean-recovery time. The mean recovery-time can be determined by measuring the area above the growth curve of a bacterial population following antimicrobial exposure. It can be shown that the previously proposed description of the post-antibiotic effect may be regarded as a special case of the definition based on the mean-recovery. Furthermore, a practical procedure is described for the quantitation of the post-antibiotic effect from a given set of data in the form of a growth curve.

Anti-Bacterial Agents↗
PubMed1991

Quantification of in-vitro post-antibiotic effect based on the mean recovery-time. II: A comparison of colony counting versus photometric methods for the determination of bacterial growth.

In the preceding paper, a method for the quantification of the post-antibiotic effect (PAE) has been developed based upon the mean recovery-time of an antibiotic-treated bacterial population, showing that the mean recovery-time is determined by the area above a growth curve of the bacterial population. Such an area determination of PAE implies that this method is less likely to be influenced by the early portion of a growth curve and therefore less dependent on the ability of a technique to detect a minimum bacterial density (sensitivity limit). In this study, this implication is further demonstrated in theory and through experimentation. As a result, an approach to estimation of contribution of the early portion of a growth curve to the quantitation of PAE based on the mean recovery-time is derived. The PAE of ciprofloxacin on Escherichia coli ATCC 25922 was determined under different test conditions using colony count and optical density measurements for determining bacterial growth. Differences in durations of the PAE quantitated by the mean recovery-time from the colony count measured and optical density measured growth curves were not statistically significant (P greater than 0.05).

Anti-Bacterial Agents↗
PubMed1990

[DNA polymorphisms and haplotypes in the apoAI-CIII gene region and coronary heart disease].

Polymorphisms and haplotypes identified by DNA Restriction Fragment Length Polymorphisms in the apoAI-CIII gene region were investigated both in 33 Chinese patients with coronary heart disease and 50 unrelated healthy subjects, using genomic DNA hybridization analysis with a 1.0 kb fragment of the human apoAI gene cDNA. The frequencies of the S2 and M2 alleles were 0.167 and 0.22 in healthy subjects, 0.11 and 0.24 in patients respectively. There were no differences in the frequencies of the S2 and M2 alleles between patients and healthy subjects. Since none of the subjects had the genotypes, S1S2M1M1, S2S2M1M2 and S2S2M1M1, all of the S2 alleles were considered to be associated with the M2 alleles at least in Chinese population. The alleles identified by the apoCIII Sst-I and apoAI Msp-I polymorphisms are in linkage disequilibrium. The individuals with the haplotype S1-M2 were significantly increased in patients compared with the ones in healthy subjects (26% versus 4.6%; chi 2 = 6.91, d.f = 1, P less than 0.01). The results of the present study suggest that both the apoCIII Sst-I and apoAI Msp-I polymorphisms may be a useful genetic marker for the analysis of apoAI-CIII gene complex and the haplotype S1-M2 may be a useful linkage marker for the putative atherogenic gene in Chinese.

Apolipoprotein A-I↗