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Biomedical subjects

H Huang

Publications and source records attributed to H Huang.

At least 469 records · Page 26Linked to original sources
PubMed1995

[Response of ovarian endodermal sinus tumor to combination chemotherapy with cis-platinum, vincristine and bleomycin or vincristine, actinomycin and cyclophosphamide].

The treatment results of 63 cases of ovarian endodermal sinus tumor admitted to Peking Union Medical College Hospital from August 1977 through April 1992 by combination chemotherapy were reported. Patients were divided into three groups. The first group received full courses of vincristine, actinomycin and cyclophosphamide (VAC) or cis-platinum, vincristine and bleomycin (PVB) chemotherapy in adequate dosages (37 cases). The second group also received VAC or PVB chemotherapy but in inadequate dosages (17 cases). The third group took no VAC or PVB chemotherapy but some other chemotherapeutic drugs (9 cases). 28 of the 63 patients died. The 35 surviving patients have been followed for 1 to 15 years. The sustained remission rates were 81.1%, 23.5% and 11.1% for the first, second and third group respectively. As the ovarian endodermal sinus tumor is very sensitive to VAC or PVB chemotherapy an extensive or aggressive cytoreductive surgery and retroperitoneal lymphadenectomy seemed to be not necessary. Such a point of view is demonstrated by our preliminary study. The treatment results for the primary cases are significantly better than that of the recurrent cases. The sustained remission rate is 94.7% for the former while that for the latter is 66.7%.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

Release of guanosine triphosphate binding protein alpha subunits from mouse myocardial membranes: basic properties and their alterations in acute murine Chagas disease.

OBJECTIVE: The aim was to investigate the arrangement of heterotrimeric alpha beta gamma G proteins in myocardial membranes using GTP gamma S dependent release characteristics of their alpha subunits in acute murine Chagas disease. METHODS: The properties of GTP gamma S dependent alpha subunit release were monitored immunochemically as well as by cholera toxin and pertussis toxin catalysed [32P]ADP ribosylation. RESULTS: GTP gamma S, as opposed to other nucleotides, caused optimal and virtually instantaneous release of soluble 40 kDa [32P]ADP ribosylated protein in pertussis toxin treated membranes. When determined immunochemically, infection decreased both the sensitivity to GTP gamma S dependent release of alpha i subunits and appeared to facilitate the appearance of GTP gamma S dependent release of alpha i3. GTP gamma S also caused the release of soluble 45 and 40 kDa proteins as detected by cholera toxin-[32P]ADP ribosylated membranes and immunochemical analysis. With regard to cholera toxin-[32P]ADP ribosylated Gs substrates sensitive to GTP gamma S dependent release, infection (1) decreased the amount of 45 kDa alpha s protein, (2) increased the amount of 40 kDa protein, and (3) enhanced sensitivity to GTP gamma S. In contrast, there was no effect of infection on the magnitude or sensitivity to GTP gamma S dependent release of immunochemical alpha s. CONCLUSIONS: The diverse characteristics of GTP gamma S dependent release of the very similar alpha subunits from myocardial membranes and their unique sensitivity to infection with T cruzi suggest that these very similar proteins are arranged within the plasma membrane in such a manner as to modify their biochemical behaviour.

Adenosine Diphosphate↗
PubMed1995

[Detection of intrauterine transmission of human cytomegalovirus by nested polymerase chain reaction].

OBJECTIVE: Using nested polymerase chain reaction (PCR) to detect Intrauterine transmission of human cytomegalovirus (HCMV). METHODS: Ninety one cases of pregnant women were devided into three groups according to their gestational stages. In the first and second trimesters, they terminated pregnancy voluntarily. HCMV-DNA in maternal and cord blood as well as placenta were detected respectively by nested PCR. RESULTS: In the first trimester, 20 out of 30 cases were infected, Intrauterine transmission occured in 8 of the 20 infected mothers (HCMV-DNA were found in the chorionic villus). In the second trimester, 21 out of 30 cases were infected, 7 of them transmitted HCMV to their fetus through placenta. In this term, the placenta infection rate is 40% (12/30). In the third trimester, 23 out of 31 cases women infected HCMV, 18 of them transmitted HCMV to their fetus through placenta, the placenta infection rate is 66.67% (20/30). The congenital infection rate is 58.06% (18/31), much higher than the reported levels marked by cord sera IgM and (or) infants viremia. CONCLUSIONS: HCMV transmitted from mother to infant mainly through placenta. Nested PCR provides a valuable method that can detected virus infection not limited by virus reproduction state and human immuno-reaction ability.

Cytomegalovirus↗
PubMed1995

[A prospective study on relationship between abnormal nasopharyngeal mucosa and nasopharyngeal carcinoma].

Abnormal nasopharyngeal mucosa was defined as abnormal finding under the examination of nasopharyngoscope. 43541 healthy persons aged 30-64 were observed for 6 years in the high risk area of NPC, by mean of EBV serological and nasopharyngeal cavity examination. The results are as follows. 1. In the high risk area of NPC, abnormal nasopharyngeal mucosa such as follicle hyperplasia and bulge are common in the younger people, especially in the post-roof of the nasopharyngeal cavity. 2. There was no significant difference on statistics between the abnormal and normal groups on the positive rate and GMT of EBV VCA/IgA. Abnormal nasopharyngeal mucosa did not change with the change of VCA/IgA titer. 3. There was significant difference on the prevalence rate of NPC between the abnormal nasopharyngeal mucosa and normal groups except the age, sex factors. There was no confirmation of the abnormal nasopharyngeal mucosa as precancerous lesion.

Adult↗
PubMed1994

Mechanism-based inhibition of human leukocyte elastase and cathepsin G by substituted dihydrouracils.

A series of dihydrouracil derivatives has been synthesized and investigated for their in vitro inhibitory activity toward human leukocyte elastase (HLE) and cathepsin G (Cath G). Alkyl [sulfonyl(oxy)] uracils 1-2 were found to be efficient, time-dependent inhibitors of elastase (kobs/[I] M-1 s-1 values ranged between 480 and 8110). These compounds formed acyl enzymes that exhibited variable hydrolytic stability which appeared to be dependent on the nature of the R1 group (believed to be accommodated at the primary specificity site, S1). The acyl enzymes formed with cathepsin G deacylated rapidly, leading to a significant regain of enzymatic activity. In sharp contrast, the corresponding phosphorus compounds 3-4 were found to be potent, time-dependent irreversible inhibitors of HLE. Furthermore, the results of the structure-activity relationship studies suggest that the binding modes of compounds 1-2 and 3-4 may be different.

Cathepsin G↗
PubMed1994

Use of a monoclonal antibody to detect DNA damage caused by the anticancer drug cis-diamminedichloroplatinum (II) in vivo and in vitro.

A monoclonal antibody, MAb62-5, was prepared and used to detect DNA damage due to the anticancer drug cis-diamminedichloroplatinum (II) (or cisplatin). ELISA competition indicated that the binding of MAb62-5 to cisplatin-DNA was competitively inhibited (50% control) by 210 nM of cisplatin bound to DNA, cisplatin/nucleotide (D/N) = 0.2. Using a DNA mobility shift assay, MAb62-5 binding activity was inhibited by 50% by approximately 50-fold molar excess of cisplatin-DNA adducts (D/N = 0.08), whereas there was less than 5% inhibition by UV-DNA adducts or mock-treated DNA. In addition, MAb62-5 showed a similar affinity to the cisplatin-DNA adducts as compared to an endogenous cisplatin-damaged DNA recognition protein. Using ELISA with this antibody, we have demonstrated a 2-fold enhancement in excision repair of cisplatin-DNA adducts in resistant HeLa cells. This is supported by the measurement of repair-associated DNA strand breaks using alkaline elution and host cell reactivation of transfected plasmid DNA carrying cisplatin damage. These findings also provide explanation for the complexicity of immunoassay in cells.

Antibodies, Monoclonal↗
PubMed1994

Relation between age, arterial distensibility, and aortic dilatation in the Marfan syndrome.

This study examined the relations between age, arterial distensibility, and systemic hemodynamics in patients with the Marfan syndrome. The study group included 170 patients referred to a specialist clinic, of whom 55 (age 26 +/- 12 years) were diagnosed as having Marfan syndrome. The remaining 115 patients (age 25 +/- 14 years) formed a control group. Each patient underwent echocardiographic examination, with measurement of ascending aorta diameter at end-diastole and end-systole, and aortic flow velocities. The elastic properties of the aorta were indexed by calculation of aortic distensibility, wall stiffness, and systemic pulse wave velocity. Mean end-diastolic aortic diameter in the Marfan group (38 +/- 9 mm) was greater than that in the controls (26 +/- 4 mm, p < 0.01). Resting heart rate and aortic flow velocities were similar in the 2 groups, but systemic arterial pulse pressure was greater in the Marfan group (50 +/- 12 mm Hg) than in the controls (41 +/- 8 mm Hg, p < 0.01). Aortic diameter increased with age in both groups, but at all ages the Marfan group exhibited greater aortic diameters (p < 0.05). Aortic distensibility was less in the Marfan group (2.6 +/- 1.3 cm2.dynes-1 x10(-6)) than in the controls (6.2 +/- 2.1 cm2.dynes-1 x 10(-6), p < 0.01), and the aortic wall stiffness index was greater in the Marfan group (7.9 +/- 3.4) than in the controls (2.8 +/- 0.6, p < 0.01). Aortic wall stiffness increased with age and aortic diameter, but at all ages the Marfan group exhibited a stiffer aorta for a given diameter than did the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Comparative RFLP mapping of an allotetraploid wild rice species (Oryza latifolia) and cultivated rice (O. sativa).

The purpose of this study was to construct a comparative RFLP map of an allotetraploid wild rice species, Oryza latifolia, and to study the relationship between the CCDD genome of O. latifolia and the AA genome of O. sativa. A set of RFLP markers, which had been previously mapped to the AA genome of cultivated rice, were used to construct the comparative map. Fifty-eight F2 progeny, which were derived from a single F1 plant, were used for segregation analysis. The comparative RFLP map contains 149 DNA markers, including 145 genomic DNA markers from cultivated rice, 3 cDNA markers from oat, and one known gene (waxy, from maize). Segregation patterns reflected the allotetraploid ancestry of O. latifolia, and the CC and DD genomes were readily distinguished by most probes tested. There is a high degree of conservation between the CCDD genome of O. latifolia and the AA genome of O. sativa based on our data, but some inversions and translocations were noted.

Biological Evolution↗
PubMed1994

Alterations in angiotensin II receptor mediated signal transduction shortly after coronary artery constriction in the rat.

OBJECTIVE: The aim of the study was to determine the effect of coronary artery constriction on the density of angiotensin II receptors and on the effector responses coupled with these receptors on myocytes one week after surgical induction of coronary artery stenosis in rats. METHODS: After induction of coronary artery stenosis and following the estimation of global cardiac performance, myocytes were enzymatically dissociated and radioligand binding studies were performed. In addition, the isotonic contractile performance, cytosolic calcium transients, and angiotensin II stimulated inositol phosphate generation in myocytes were measured in the presence and absence of the angiotensin II receptor subtype antagonist losartan. RESULTS: After documenting left ventricular failure and right ventricular dysfunction, the expression and density of angiotensin II receptors in left ventricular myocytes were evaluated and found to be increased 3.1-fold and 4.1-fold, respectively. Corresponding increases in right ventricular myocytes were 3.6-fold and 4.5-fold. In contrast, the quantity of the regulatory protein Gq alpha was not altered in either ventricle. Angiotensin II did not increase the generation of total inositol phosphates in left and right ventricular myocytes at maximum stimulation. However, the threshold for the formation of inositol phosphates was lowered in left ventricular myocytes of coronary narrowed rats. Measurements of single cell mechanics indicated that angiotensin II stimulation markedly improved the depression in myocyte function biventricularly. This inotropic effect was coupled with the restoration of cytosolic calcium. CONCLUSIONS: The upregulation of angiotensin II receptors on myocytes in this model of global ischaemia may be a compensatory mechanism ameliorating myocyte contractility in an attempt to sustain ventricular pump function.

Angiotensin II↗
PubMed1994

Active oxygen species are involved in the induction of micronuclei by arsenite in XRS-5 cells.

The human carcinogen, arsenic, is genotoxic to mammalian cells in vitro. The mechanism is largely unknown, although the involvement of free radicals has been suggested. Since the X-ray sensitive Chinese hamster ovary cell line, XRS-5, is also sensitive to several free-radical generating agents, including H2O2, we have used this cell line to test whether the genotoxic effect of arsenite is mediated via the generation of active-oxygen species. The results indicate that the XRS-5 cells are more sensitive to arsenite in terms of cell-killing and micronucleus induction compared to the parental CHO-K1 cells. The level of arsenic uptake and release, the levels of elementary components for arsenic detoxification, glutathione and glutathione S-transferase activities in these two cell lines are very similar. The XRS-5 cells, however, were shown to have 6-fold lower catalase activity in comparison to CHO-K1 cells. Moreover, catalase could effectively reduce the frequency of arsenite-induced micronuclei. These results indicate that the low catalase activity may be an important reason why XRS-5 cells are more sensitive to the toxic effects of arsenite, and arsenite probably induces micronuclei via the overproduction of H2O2. The XRS-5 cells had a higher background level of micronuclei, and were also more sensitive to gamma-rays in terms of induction of micronuclei. Catalase, however, did not reduce the background level or the frequency of gamma-ray-induced micronuclei. Therefore, the lower catalase activity seems to bear little relation to the high background level of micronuclei and the hypersensitivity to gamma-rays in micronucleus induction in XRS-5 cells.

Animals↗