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Biomedical subjects

Z Huang

Publications and source records attributed to Z Huang.

At least 415 records · Page 23Linked to original sources
PubMed1995

[Medicine of Liao Dynasty].

The Taizhu Emperor of Liao Dynasty forced the popularization of medical knowledge by imitating that of the Tang Dynasty. After entering the Capital Bian, Taizong Emperor, seized the medical men of Jin to the North, while Jingzong Emperor treasured medicine. All the above had pushed the development of Liao's medicine in Northern China to its mature stage. Special administration institutions for medicine were established. Autopsy and anatomy were advocated. Therapeutic modalities were mainly TCM, traditional materia medica and acu-moxibustion. Zhilugu and Yeludilu were among the famous physicians. However, viewing from an overall standpoints, Liao medicin was rather backward. Due to its small territory, religious superstition and special humanities and geographical conditions, the development was rather limited.

China↗
PubMed1995

[The protective effect of IL-1 beta on stress-induced gastric mucosal damage in rat].

The effect of recombinant IL-1 beta on stress-induced gastric mucosal lessions was studied in rats. Pretreatment with IL-1 beta prevented formation of gastric mucosal damage in a dose-dependent manner. IL-1 receptor antagonist peptide (IRAP) could totally reverse the protective effect of IL-1 beta. IL-1 fragment peptide (163-171) had no effect on gastric ulcer formation in the experimental model, whereas sulfhydryl blocker N-ehtylmaleimide partially blocked the protective effect of IL-1 beta. The concentration of protein and noneprotein sulfhydryls in the gastric mucosa was significantly decreased 3 h after stress, and this decrease was partially prevented by IL-1 beta. IL-1 beta also decreased the concentration of molondialdehyde (MDA) in the gastric mucosa after 3 h stress. The results suggest that IL-1 beta could effectively lessen the degree of stress-induced gastric mucosal damage, due possibly to the production of endogenous sulfhydryl compounds in the gastric mucosa.

Animals↗
PubMed1995

[Basaloid squamous carcinoma of the oesophagus: a distinctive clinico-pathological entity].

5 cases of basaloid-squamous carcinoma (BSC) of oesophagus were reported. Their pathological features were: 1. The main component of the tumors were basaloid carcinoma cells. 2. Concomitant squamous cell differentiation. 3. Comedo-like necrosis in the basaloid carcinoma component of the tumor. 4. Hyaline degeneration within the stroma of the basaloid carcinoma nests (PAS+). The immunohistochemistry of keratin 10.11, CEA and EMA in the basaloid carcinoma component of BSC were negative or weak positive, while actin and S-100 were positive in some parts of the tumor sections. This suggested that the carcinoma component was poorly differentiated and somewhat tended to differentiate toward myoepithelia or other directions. We therefore consider that the origin of BSC may be the primitive totipotential cell. BSC occurred more frequently in elderly males. The biological behavior of BSC was highly malignant. Regional lymph nodes or distant organ metastasis were usually found at the first operation. The mean survival period after operation was very short, BSC was therefore considered to be a specific clinicopathological entity.

Actins↗
PubMed1995

Percutaneous endovascular embolization of intracerebral arteriovenous malformations. Experience in 72 cases.

Endovascular therapeutic embolization of arteriovenous malformations (AVMs) of the brain was performed in 72 patients between October 1986 and March 1993. From October 1986 to May 1991, 38 patients in this series were treated with isobuty1-2-cyanoacrylate (IBCA) glue. After June 1991, in the remaining 34 patients the embolic materials used included surgical silk (5-0), polyvinyl alcohol (PVA), ethanol, and estrogen. After treatment, 29 patients (40.3%) had complete angiographic obliteration of AVM, 15 (21%) transient neurologic postembolization deficit, and 3 (4%) permanent deficit without death. Embolic agents and procedures are discussed as to their curative effects, safety, normal perfusion pressure breakthrough (NPPB) problem, with silk mixture fluid being considered preferable.

Adolescent↗
PubMed1995

[Effect of electroacupuncture on the discharges of pain-sensitive neurons in the hypothalamic dorsomedial nucleus of rats].

The discharges of pain-sensitive neurons of the hypothalamic dorsomedial nucleus (DMH) in Sprague-Dawley rats were recorded with glass microelectrodes, After electroacupuncture acupoints "Zusanli" and "Sanyinjiao", the rate of spontaneous discharges and the rate and duration of the pain-evoked discharges of pain-excitatory units of DMH were profoundly decreased, and the spontaneous firing rate of pain-inhibitory units was increased while their inhibitory response to nociceptive stimulation was released by the electroacupuncture. The results mentioned above suggest that DMH participates in the activity of acupuncture analgesia.

Acupuncture Analgesia↗
PubMed1995

[A study on the relative factors for secondary parathyroidosis and renal osteodystrophy in long-term hemodialysis patients].

The authors classified sixty chronic renal failure (CRF) patients receiving hemodialysis (HD) treatment into four groups for clinical study. Forty patients received HD for more than five years and the remaining twenty patients received HD for less than two years. These two groups were further divided into two subgroups according to whether they took Rocaltrol or not. The levels of parathyroid hormone (PTH), calcitonin (CT), alkaline phosphatase (AKP) and bone X-ray were studied in each patient. The results showed: the levels of PTH and CT were obviously increased in all the patients. The levels of PTH and CT were higher in the patients having received HD for more than five years than those for less than two years. They were also higher in patients who had not taken Rocatrol than those who had. Ninety-five percent of the patients having received HD for more than five years had renal osteodystrophy (ROD) without receiving Rocaltrol treatment, while only sixty-five percent of the patients developed ROD with Rocatrol treatment. The longer the HD time, the higher the ROD incidence. The cause, prevention and treatment of ROD were discussed.

Adult↗
PubMed1995

Nucleotide sequence of maize dwarf mosaic virus capsid protein gene and its expression in Escherichia coli.

The 3'-terminal 1,279 nucleotide sequence of maize dwarf mosaic virus (MDMV) genome has been determined. This sequence contains an open reading frame of 1,023 nucleotides and a 3'-non-coding region of 256 nucleotides. The open reading frame includes all of the coding regions for the viral capsid protein (CP) and part of the viral nuclear inclusion protein (NIb). The predicted viral CP consists of 313 amino acid residues with a calculated molecular weight of 35,400. The amino acid sequence of the viral CP derived from MDMV cDNA shows about 47%-54% homology to that of 4 other potyviruses. The viral CP gene was constructed in frame with the lacZ gene in pUC19 plasmid and expressed in E. coli cells. The fusion polypeptide positively reacted in Western blot with an antiserum prepared against the native viral CP.

Amino Acid Sequence↗
PubMed1995

Fluorescence spectroscopic study of the interaction of adenine and nucleotide with trichosanthin.

Trichosanthin (TCS) is an N-glycosidase that can attack the 28s rRNA of the ribosome at a highly conserved adenine residue. The interactions of adenine and its derivative nucleotides with TCS are reported. The fluorescence of Trp 192 of TCS is sensitive to the proximity of adenine, and produces a marked red shift indicative of trytophan in a more hydrophilic environment. By contrast AMP and ATP quench the maximal emission at 328nm. The binding of the adenine and ATP with TCS result in lower tryptophan accessibility to the quencher acrylamide, but higher tryptophan accessibility to the quencher iodide, while AMP caused higher tryptophan accessibility to acrylamide, and lower tryptophan accessibility to iodide. Also, the binding of nucleotides induces tryptophan heterogeneity in the protein. These findings lead us to propose that binding of nucleotides and adenine base cause different microenvironmental changes of the tryptophan residue, and Trp 192 may be involved in the active site of TCS.

Adenine↗
PubMed1995

[A study on duration of using VCu200 intrauterine device].

OBJECTIVE: To make certain of the duration of using V-copper 200mm2 intrauterine device (VCu200 IUD). METHODS: Six hundreds and sixty six pieces of VCu200 IUD used for different time period and removed for various reasons were analyzed. The life span of VCu200 IUD depended on corrosion, fragmentation and damage of copper wire and these parameters were measured on VCu200 IUD removed. RESULTS: There were significant difference in copper wire fragmentation rate between tenth year-group and fifteenth year group which were 12.36%, 25.53% respectively (P < 0.001), and so were the expulsion rate of copper wire 2.54%, 9.57% respectively (P < 0.05). The copper loss and copper releasing rate in tenth year-group were 39.73%, 22.95%micrograms/day respectively. Copper corrosion resulted in fragmentation of copper wire which occurred the earliest in three years of use and expulsion of copper wire segment occurred after five years of use. CONCLUSION: Comparing the above results with other copper intrauterine devices, it was suggested that the suitable duration of VCu200 IUD use was ten years.

Equipment Failure↗
PubMed1995

Multimodality therapy including surgical resection for limited small cell lung cancer.

From 1975 through 1990, 199 patients with limited small cell lung cancer (LSCLC) were subjected to multimodality treatment including surgical resection combined with chemotherapy or chemoradiotherapy in our department. The median postoperative survival time of the 199 patients was 39 months, and the 5-year survival rate was 26%, which was decreased with increase of tumor-stage. In comparison of the survival time of patients in Stage I and those in Stage IIIa, there was a significant difference (P < 0.01). There were no significant differences in survival rate of 3 and 5 years between the patients receiving chemotherapy prior to or after surgical resection. The improvement in survival was documented by surgical resection combined with chemotherapy or chemoradiotherapy for LSCLC. The effect of multimodality treatment is correlated with tumor P-TNM staging, the involvement of lymph node, especially that of the mediastinal lymph node, is a negative factor influencing the prognosis. Surgical resection is an initial management, followed by chemotherapy or chemoradiotherapy may be indicated in LSCLC patients of Stage I, Stage II and some Stage IIIa as the cancer can be resected completely.

Adult↗
PubMed1995

Human cytochromes P4501A1 and P4501A2: R-warfarin metabolism as a probe.

Two forms of the cytochrome P450 enzyme superfamily, P4501A1 and P4501A2, that are heterogeneously distributed in populations and are induced in response to environmental factors are important because of their capacity to bioactivate procarcinogens. Phenotyping P4501A1 and P4501A2 in individuals will thus provide assessments of those individuals' susceptibility to procarcinogens. The anticoagulant drug warfarin is metabolized by human P4501A1 and P4501A2, and we have characterized this metabolism for the R-warfarin enantiomer as a potential in vivo probe. cDNA-expressed human P4501A1 and P4501A2 are regioselective for R-warfarin 6- and 8-hydroxylation with very similar KM values: 1.4 mM (6-hydroxylation), 1.2 mM (8-hydroxylation), 1.6 mM (6-hydroxylation), and 1.4 mM (8-hydroxylation), respectively, indicating possible binding competition for R-warfarin between the two forms. However, when comparing 6- and 8-hydroxylation, P4501A1 showed weak regioselectivity for 8-hydroxylation, whereas P4501A2 exhibited strong regioselectivity for 6-hydroxylation, with 6-hydroxylation/8-hydroxylation ratios of 0.6 and 5.0, respectively. These findings were confirmed by using microsomes from 2,3,7,8-tetrachlorodibenzo-p-dioxin-treated HepG2 and MCF-7 cells expressing only P4501A1 (ratios of 0.7), and from human hepatic microsomal preparations containing only P4501A2 (average ratios of 4.0). P4501A2 levels in the liver preparations, as assessed by densitometry of immunoblots, correlated with R-warfarin 6-hydroxylation rates (r2 = 0.83) and caffeine 3-demethylation rates (r2 = 0.67), but not with R-warfarin 8-hydroxylation rates. P450s 2A6, 2B6, 2C9, 2D6, 2E1, and 3A4 did not yield either 6- or 8-hydroxy-warfarin from R-warfarin. We conclude that R-warfarin 6-hydroxylation rates are markers for human hepatic P4501A2, whereas ratios of 6-hydroxylation/8-hydroxylation could be used in vitro as a marker for P4501A1.

Base Sequence↗
PubMed1995

[The trend of the gallstone disease in China over the past decade].

The present study is the second national survey on 3911 srugically treated cases of gallstones which was collected from 33 hospitals of 5 provinces and 2 main cities of China and aims at reevaluating and comparing the trend of the gallstone disease in China since the first national survey was completed 10 years ago. The results showed that cholelithiasis remained one of the commonest surgical diseases and accounted for 11.5% of overall hospitalized patients during the same period of time and it occurred mostly in females of over 50 years of age, with a female-male ratio of 2.57 Vs 1.80% of the patients with single positioned gallstones had their stones in gallbladder and was mainly cholesterol stone in nature while pigmented bile duct stones was found only in 10% of the patients, which made the gallbladder Vs bile duct stone ratio and the cholesterol Vs pigment stone ratio a significant difference as 7.36 : 1 and 3.4 : 1 respectively when compared with the results of 1.5 : 1 and 3.4 : 1 from the first national survey, 10 years ago. A significantly decreased incidence of biliary ascariasis and biliary bacterial infection rate as well as the dietary changes from low protein, fat high vegetable to the opposite were directly relevant to the above alterations on the location and the type of the gallstones.

Adolescent↗
PubMed1995

Scrapie prions: a three-dimensional model of an infectious fragment.

Backgound. A conformational change seems to represent the major difference between the scrapie prion protein (PrPSc) and its normal cellular isoform (PrPC). We recently proposed a set of four helix bundle models for the three-dimensional structure of PrPC that are consistent with a variety of spectroscopic and genetic data. Results. We report a plausible model for the three-dimensional structure of a biologically important fragment of PrPSc. The model of residues 108-218 was constructed by an approach that combines computational techniques and experimental data. The proposed structures of this fragment of PrPSc display a four-stranded beta-sheet covered on one face by two alpha-helices. Residues implicated in the prion species barrier are found to cluster on the solvent-accessible surface of the beta-sheet of one of the models. This interface could provide a structural template that would assist the conversion of PrPC to PrPSc and hence direct prion propagation. Conclusion. Molecular models of the PrP isoforms should prove very useful in developing structural hypotheses about the process by which PrPC is transformed into PrPSc, the mechanisms by which PrP gene mutations give rise to the inherited human prion diseases, and the species barrier that seems to protect humans from animal prions. It seems likely that PrPC represents a kinetically trapped intermediate in PrP folding.

Journal Article↗
PubMed1994

Nonadditivity of mutational effects at the folate binding site of Escherichia coli dihydrofolate reductase.

The function of the hydrophobic residues Leu28, Phe31, Ile50, and Leu54 at the folate binding site in Escherichia coli dihydrofolate reductase (5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) has been studied by a combination of site-specific mutagenesis and reaction kinetics. Studies suggest that the overall protein structure and kinetic sequence for the reaction did not change for the mutant proteins compared to the wild-type enzyme. Two sets of mutated reductases have been constructed. The first set, in which the side chains of the targeted amino acids are spatially well separated (approximately 8 A), includes two single mutants (L28Y and L54F) and a double mutant (L28Y-L54F). This set features residues that increased the side chain surface area and the potential for substrate interactions. Unexpectedly, nonadditivity in the free energy changes for the thermodynamics of ligand binding and in the rates of hydride transfer and product release is observed. The progressive increase in dihydrofolate binding is reversed for the sterically more crowded double mutant, with delta delta G ca. 3 kcal mol-1 less favorable than anticipated. On the other hand, the decrease in the rate constant for hydride transfer noted with the single mutants relative to the wild-type enzyme is reversed for the double mutant, so that delta delta G not equal to is ca. 2 kcal mol-1 more favorable. The second set of mutant proteins includes two double mutants (L28A-F31A and I50A-L54G) in which the selected amino acids are separated by three to four intervening amino acids and a quadruple mutant (L28A-F31A-I50A-L54G) in which the two sets L28A-F31A and I50A-L54G are spatially distinct. This set deleted the side chain surface area to lower the opportunity for substrate interactions. Nonadditivity in the free energy changes associated with key kinetic and thermodynamic parameters is again observed. The decrease in dihydrofolate binding found with the two double mutants is not observed with the quadruple mutant, which binds the substrate with delta delta G ca. 6.5 kcal mol-1 more favorable than expected. Similarly, the quadruple mutant has a larger rate constant for hydride transfer (-delta delta G not equal to congruent to 1.7 kcal mol-1) than predicted. One interpretation for the nonadditivity is that these residues interact through binding of the folate substrate, which serves to link molecularly remote side chain moieties within the active site.(ABSTRACT TRUNCATED AT 400 WORDS)

Base Sequence↗
PubMed1994

Effects of cerebral ischemia in mice deficient in neuronal nitric oxide synthase.

The proposal that nitric oxide (NO) or its reactant products mediate toxicity in brain remains controversial in part because of the use of nonselective agents that block NO formation in neuronal, glial, and vascular compartments. In mutant mice deficient in neuronal NO synthase (NOS) activity, infarct volumes decreased significantly 24 and 72 hours after middle cerebral artery occlusion, and the neurological deficits were less than those in normal mice. This result could not be accounted for by differences in blood flow or vascular anatomy. However, infarct size in the mutant became larger after endothelial NOS inhibition by nitro-L-arginine administration. Hence, neuronal NO production appears to exacerbate acute ischemic injury, whereas vascular NO protects after middle cerebral artery occlusion. The data emphasize the importance of developing selective inhibitors of the neuronal isoform.

Amino Acid Oxidoreductases↗