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Biomedical subjects

Y Tang

Publications and source records attributed to Y Tang.

At least 217 records · Page 12Linked to original sources
PubMed1999

Inhibitory actions of polysaccharide sulfate on action potentials and contraction of papillary muscles in guinea pigs.

AIM: To examine the effects of polysaccharide sulfate (PSS) on the action potentials and contractile force in guinea pig papillary muscles. METHODS: Using intracellular microelectrode to record fast (FAP) and slow (SAP) action potentials. RESULTS: PSS (> or = 50 mg.L-1) caused concentration-dependent decreases in the contractile force and the action potential duration (APD) of FAP without affecting the resting potential (RP), action potential amplitude (APA), and maximal upstroke velocity (Vmax). The Vmax, APA, and APD of BaCl2-induced SAP were concentration-dependently decreased by PSS (> or = 15 mg.L-1) and the effects were antagonized by isoprenaline (1 mumol.L-1). The APA and APD of isoprenaline-induced SAP were decreased by PSS (> or = 15 mg.L-1) in a concentration-dependent manner and the effects were attenuated by elevation of extracellular Ca2+ concentration. CONCLUSION: PSS selectively inhibited the slow inward current.

Action Potentials↗
PubMed1999

[Study of surgical depilation in pig and human body].

OBJECTIVE: The study is to show how much dermis and the follicles within it should be removed in order to prevent hair regeneration. METHODS: The experiment used Wuzhishan mini pigs. Different thickness of the pig's dermis and the follicles within it were removed to observe hair regeneration. According to the result, the dermis and the follicles were removed from the scalps of 62 patients from Jan. 1995 to Dec. 1996. Subsequent hair regeneration was observed. RESULTS: Using surgical depilation to remove 1/4-2/5 thickness of the scalp dermis and the follicles within it stopped most of the hair regeneration. The rate of hair regeneration was 10-30%. Satisfactory clinical effects were achieved. CONCLUSION: Surgical depilation is a simple, effective, cheap way for hair removing.

Adolescent↗
PubMed1999

Molecular mechanism of recessive congenital methemoglobinemia in Chinese pedigrees.

OBJECTIVE: To investigate the molecular mechanism of recessive congenital methemoglobinemia (RCM) in Chinese and to establish a gene diagnostic method of polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP). METHODS: Total RNA was isolated from the peripheral leukocytes of the propositus and b5R cDNA synthesized by reverse transcription-polymerase chain reaction (RT-PCR). The coding region of b5R cDNA was analyzed by sequencing of the RT-PCR products. RESULTS: Both propositi A and B were found to be homozygotes for a G to A transition at codon 57 in exon 3, changing a guanine to an adenine. This point mutation was not an artificial occurrence during polymerase chain reaction (PCR), as confirmed by Msp I restriction enzyme analysis of the genomic DNA. Propositus A's mother and propositus B's sister and her nephew were found to be heterozygotes for the mutation. CONCLUSION: A guanine-to-adenine transition at codon 57, replacing arginine with glutamine, was the molecular basis for RCM in two Chinese families.

Adult↗
PubMed1999

[The isolation and drug susceptibility of penicillin resistant Streptococcus pneumoniae in Guangzhou].

OBJECTIVE: To investigate the isolation rate and drug susceptibility of PRSP in Guangzhou and in vitro antimicrobial activities of 8 antimicrobial agents against PRSP. METHODS: MICs were tested by E-test. RESULTS: Of 102 strains of Streptococcus pneumoniae, 12 strains were low-level resistant against penicillin (isolation rate 11.8%) and the antimicrobial activites of 5 drugs (augmentin, cefaclor, ceftriaxone, cefuraxime, ofloxaxin) against them were within their MICs, augmentin and ceftriaxone being the most powerful. They were resistant to azithromicin, oxacillin and penicillin. CONCLUSIONS: The isolation rate of Penicillin resistant Streptococcus pneumoniae was not high in Guangzhou, but it may increase with the extensive use of antimicrobial agents, which deserves much attention.

Anti-Bacterial Agents↗
PubMed1999

[Effects of short veno-venous hemofiltration on severe acute pancreatitis].

OBJECTIVE: To estimate the effects of therapy of short veno-venous hemofiltration (SVVH, 4hr) on severe acute pancreatitis (SAP). METHODS: Twenty patients were divided randomly into hemofiltration group (HF, 10 pts) and non-hemofiltration group (NHF, 10 pts). The local, systemic manifestations were compared between two groups; and the concentration of serum pro-inflammatory cytokines (TNFalpha, IL-1beta, IL-6, IL-8, sIL-2R) and anti-inflammatory cytokines (IL-2, IL-10) were determined at different observation points. RESULTS: In the HF and NHF group, the duration for disappearance of abdominal pain and tenderness, and amelioration for abdominal distension was (8.5 +/- 6.3) d vs. (90.0 +/- 49.0) d and (16.9 +/- 5.2) d vs. (63.4 +/- 36.0) d. CT scores at the 14th day and APACHE II scores at the 10th day was (5.6 +/- 1.3) vs. (7.7 +/- 0.8) and (4.5 +/- 1.5) vs. (7.4 +/- 2.1). The average hospital stay and cost of therapy were (33.0 +/- 20.7) d vs. (56.4 +/- 16.0) d and (53,200 +/- 16,000) vs. (89,100 +/- 25,000) RMB (P < 0.05). The concentration of 5 serum pro-inflammatory cytokines at each observation points after hemofiltration was decreased significantly (P < 0.05) in the HF group. But the concentration of the two serum anti-inflammatory cytokines was increased significantly (P < 0.05) as compared with that of the NHF group. CONCLUSIONS: Through SVVH, the imbalance of pro-inflammatory and anti-inflammatory cytokines has been corrected at early stage; thus, the severity of the disease is ameliorated significantly and the efficacy of therapy is increased.

Female↗
PubMed1999

[Application of cerium cytochemical method in observation of renal injury caused by oxygen free radical with cadmium induction].

OBJECTIVE: To study acute renal injury caused by oxygen free radical with cadmium induction. METHODS: Electron microscopy cytochemical and energy dispersive X-ray (EDX) analysis techniques were used. RESULTS: Cadmium ions could enter the epithelial cells of renal proximal convoluted tubules. Excessive production of oxygen free radical was found in the kidney tissues, which located mainly in the endothelial cells of blood vessels, mitochondria of epithelial cells of renal proximal convoluted tubules, microvilli and basement membrane. Swelling of epithelial cells and mitochondria and drop of epithelial cells could occur in renal proximal convoluted tubules. CONCLUSION: It suggests that cadmium ions can induce the formation of large amount of oxygen free radical and cause renal injury.

Acute Kidney Injury↗
PubMed1999

[The effect of defibrase in prevention of experimental atherosclerosis in rabbits].

OBJECTIVE: To study the anti-atherosclerosis effect of difibrase in rabbits. METHODS: Use of computer, light microscope, electron microscope, biochemistry and histochemical methods to identify the total cholesterol (TC) content, mean plaque area in aorta and its cholesterol content, degree of stenosis of coronary arteries of the experimental animals and control animals. RESULTS: Defibrase could decrease the mean plaque area of aorta and the TC content in the experimental animal group was less than that in the control group (P < 0.01). The findings in aortic arches and thoracic aorta were similar to those in the aorta (P < 0.05, P < 0.01). The number of plaques at the small artery openings in the thoracic aorta and abdominal aorta of the experimental group were less than that of the control group (P < 0.01). The cross sections made at the upper third of all hearts showed that the degree of stenosis of coronary artery branches in the heart wall of the experimental group was much less than that of the control group. CONCLUSION: Defibrase can significantly inhibit atherosclerosis.

Animals↗
PubMed1999

[Diagnosis and treatment of internal jugular phlebectasia (three cases report].

OBJECTIVE: To discuss the diagnosis and treatment of patients with rare abnormal veins: the internal jugular phlebectasia. METHODS: Three patients with swollen during straining or crying were diagnosed as internal jugular vein dilatation by ultra-sonography, DSA and MRI. Then an operation of envelopment of the right internal jugular vein with the sternocleidomastoid muscle was performed in two cases. In the third case, the bilateral internal jugular ectasia, the right internal jugular vein were resected and the left internal jugular vein was enveloped with the resected vein. RESULTS: These three patients were treated satisfactorily by operation, and no recurrence in the following two years. CONCLUSION: To those who want their internal jugular phlebectasia to be treated, the operation of envelopment of internal jugular vein with sternocleidomastoid muscle is a good method.

Adolescent↗
PubMed1999

[Determination of serum proteins by high performance capillary zone electrophoresis].

The separation method of serum proteins was established with an untreared 50 microns i.d. x 47 cm (40 cm to detector) capillary and detection of absorbance at 200 nm. Analysis was performed by pressure injectction 17.23 kPa.s and by applying 23 kV in the constant voltage mode. Serum samples were diluted 40-folds with assay buffer (12.5 mmol/L sodium borate, 1 mmol/L calcium lactate, 0.7 mmol/L magnesium sulfate, 1 mmol/L EDTA were mixed). A normal control serum protein was separated into 6 fractions. In pregnant serum, the alpha 0 was an additionally unknown fraction. Comparison of capillary electrophoresis with conventional cellulose acetate electrophoresis for analysis of serum proteins from normal control, pregnant women multiple myeloma and tonic rachitis patients indicates that capillary clectrophoresis is a new technique for the analysis of serum proteins because of its high efficiency, on-line data processing and automation. Capillary electrophoresis is the reliable technique for clinical diagnosis of serum protein abnormalities.

Albumins↗
PubMed1999

[Purification and properties of glutamate dehydrogenase from Pseudomonas pseudoalcaligenes].

Glutamate dehydrogenase was purified from the crude extract of Pseudomonas pseudoal-caligenes. The enzyme had a molecular weight of 290,000 and was composed of six subunits with identical molecular weight of 47,000. The enzyme was highly specific for NADP(H) and the substrates. The biochemical properties such as kinetic parameters and heat stability were also examined. The purified GDH showed considerable loss of activity upon freezing.

Glutamate Dehydrogenase↗
PubMed1999

[The influence of interferon alpha neutralizing antibodies on the therapeutic effectiveness in patients with chronic viral hepatitis].

OBJECTIVE: To study the influence of interferon alpha (IFN-alpha) neutralizing antibody (NA) on the therapeutic effectiveness of IFN-alpha. METHODS: 30 healthy persons and 116 patients with chronic viral hepatitis treated with IFN-alpha were studied, and the NA in their sera were tested by using the antiviral neutralizing bioassay (ANB). RESULTS: None was positive for NA in sera of the healthy persons and patients before IFN-alpha treatment, 20 of 116 patients developed NA after IFN-alpha therapy, the positivity was 17.2% (20/116). NA appeared after 2 months of alpha IFN treatment, all 20 patients were positive after 6 months. The NA positivity in treated groups of IFN-alpha 2a, IFN-alpha 2b and IFN-alpha 1b were 34.6%, 13.2% and 11.5% respectively. The clearance rates of virus in NA-positive group and NA high-titered group were significantly lower than those in NA-negative group and NA low-titered group (P < 0.01 and P < 0.05, respectively) In contrast, the relapse rates of virus in NA-positive group was markedly higher than that in NA-negative group (P < 0.05). CONCLUSION: NA may develop with its regularity in the chronic viral hepatitis patients treated with alpha IFN. The frequencies of NA development are related with the subtypes of alpha IFN used. NA can inhibit IFN activity, thereby affecting the therapeutic effectiveness of IFN.

Adult↗
PubMed1999

[Study on the determination method of Mo in the internal organs of body by graphite furnace atomic absorption spectrophotometry].

A new method for the determination of Mo in the heart by tantalum-lining graphite tube was developed. The tantalum-lining graphite tube can entirely eliminate effects of stable carbide formed. The sensitivity was enhanced to compare with the conventional graphite tube. At the same time, it also climinates memory effect completely and reduces the interferences of coexistent elements such as Fe, Na, K etc. The method is simple, accurate and rapid.

Humans↗
PubMed1999

[Spectrophotometric determination of trace amount of cadmium in marine products].

The colour reaction of Cd(II) on xylend orange in the presence of hexamethylenetetramine-KNO3-HNO3 has been studied. Cd(II) forms the complex at pH = 6.2-6.4 (lambda(max) = 578.4 nm) with an apparent molar absorptivity of 1.6 x 10(4) L x mol(-1) x cm(-1). Beer's law is obeyed for Cd(II) in the range of 0.5-6 microg x mL(-1). The detection limit is 0.007 microg x mL(-1) with the recovery of 90%-105%. The method is simple and highly sensitive, and has been applied to the analysis of sample with satisfactory results.

Animals↗
PubMed1998

Absence of antinociceptive tolerance to improgan, a cimetidine analog, in rats.

Improgan, an analog of the histamine receptor antagonist cimetidine, produces highly effective analgesia following intraventricular injection. The present study examined changes in the antinociceptive effects of improgan following once daily intraventricular injections. Improgan (100-150 microg) produced near maximal antinociception 10 and 30 min after daily administration on all 4 test days, whereas comparable morphine treatments (50 microg) induced considerable tolerance. Thus, improgan produced highly effective analgesia without the development of tolerance.

Analgesics, Non-Narcotic↗
PubMed1998

X-ray studies on two forms of bovine beta-trypsin crystals in neat cyclohexane.

Two orthorhombic forms (Vm values are 2.3 and 3.0 A3/Da) of bovine beta-trypsin crystals in neat cyclohexane were determined to 1.93 A resolution, by X-ray diffraction. Both structures in organic solvent are similar to those in aqueous solution. In the high packing density form, one cyclohexane molecule is found in a hydrophobic site near the active center. One sulfate locates at the active site with hydrogen or salt bond to the Ser-His catalytic diad, and five more sulfates bind on the molecular surface. The conformation of the side chains near the sulfates changed greatly. In the low packing density form, one cyclohexane and three sulfates are found. In both structures, one benzamidine molecule locates at the hydrophobic pocket of the active center. Most water molecules on the enzyme surface are retained except some with high temperature factors.

Animals↗
PubMed1998

Differences in susceptibility to tumor necrosis factor alpha-induced apoptosis among MCF-7 breast cancer cell variants.

Widespread use of MCF-7 human breast carcinoma cells as a model system for breast cancer has led to variations in these cells between different laboratories. Although several reports have addressed these differences in terms of proliferation and estrogenic response, variations in sensitivity to apoptosis have not yet been described. Tumor necrosis factor alpha (TNF-alpha) has been shown to both induce apoptosis and inhibit proliferation in MCF-7 cells. We observed that TNF-alpha inhibited proliferation in MCF-7 cell variants from three different laboratories (designated M, L, and N). MCF-7 M cells were resistant to TNF-alpha-induced apoptosis, whereas MCF-7 L cells were moderately resistant to the effect of TNF-alpha. A third variant, MCF-7 N, underwent apoptosis when exposed to TNF-alpha. Analysis of the p55 TNF-alpha receptor (TNFR) 1 expression revealed the greatest expression in MCF-7 N cells, whereas the MCF-7 L and M cells expressed 89 and 67% of MCF-7 N cell TNFR1 levels, respectively. Ceramide generation occurred in all three variants in response to TNF-alpha treatment, with MCF-7 N cells expressing the greatest increase. Cleavage of the CPP32/caspase 3 substrate poly(ADP-ribose) was observed in MCF-7 N and L cells as early as 3 and 6 h, respectively, but poly(ADP-ribose) cleavage was not observed in MCF-7 M cells. The delayed protease activation in the L variant may represent the mechanism by which these cells display delayed sensitivity to TNF-a-induced apoptosis. Expression of the Bcl-2, Mcl-1, Bcl-X, Bax, and Bak proteins was analyzed to determine whether the differences in MCF-7 cell sensitivity to apoptosis could be correlated to the differential expression of these proteins. Whereas Bak, Bcl-X, and Mcl-1 levels were identical between variants, the levels of Bcl-2 were 3.5-3.8-fold higher and the levels of Bax were 1.5-1.7-fold lower in the resistant variants (M and L) as compared with those of the sensitive variant (N). Taken together, these results suggest that differences in susceptibility to TNF-alpha-induced apoptosis among MCF-7 breast cancer cell variants may be explained by differences in TNFR expression, ceramide generation, differential expression of the Bcl-2 family of proteins, and protease activation.

Apoptosis↗