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Biomedical subjects

Y Huang

Publications and source records attributed to Y Huang.

At least 901 records · Page 50Linked to original sources
PubMed1996

Local electroretinogram and pattern visual evoked potential in maculopathies.

PURPOSES: To observe the characteristics of local electroretinogram (LERG) in normal subjects and patients with maculopathies, and to evaluate the applied worth of LERG and pattern visual evoked potential (PVEP) in maculopathies. METHODS: LERGs at 5 degrees and 15 degrees macular regions were recorded from 27 normal subjects (54 eyes). The factors of age, different eyes and stimulate areas for LERG influence were observed. Meanwhile, the LERG and PVEP were recorded from 25 patients (35 eyes) with maculopathies for making contrast study. RESULTS: In normal subjects, there was no significant influence of age to LERG. As the stimulated areas increased, the a- and b-wave amplitudes of LERG increased. In the patients with maculopathies, the a- and b-wave amplitudes of LERG at 5 degrees, 10 degrees and 15 degrees macular regions were significantly lowered and the mean values of P1 latency were prolonged and N1-P1 amplitudes of VEP were lowered, comparing with the control group. In the nearing stimulated area (5 degrees LERG and 14.9 x 19 degrees PVEP), there were no significant differences of the abnormal rates of both LERG and PVEP. CONCLUSION: There are close sensitivities of testing the function of macular region with LERG and PVEP in maculopathies. However, LERG is not influenced by the visual path diseases and visual acuity, it is a more effective and direct way than PVEP in measuring macular function.

Adolescent↗
PubMed1996

[Multiple organ failure in burn patients combined with inhalation injury].

To define the clinical features and prevention and treatment of multiple organ failure (MOF) developed in burn patients combined with inhalation injury, a retrospective clinical study on 4834 burn patients admitted into the Institute from Jan, 1977 to Aug, 1991, in which 366 cases sustained inhalation injury, was performed. It was shown that postburn MOF occurred in 115 cases among the 4834 victims, with an incidence of 2.38%. However, of the 366 cases with inhalation injury 76 were complicated with MOF, an incidence as high as 20.77%, approximately occupying two-thirds of the postburn MOF. The incidence and mortality of MOF were higher when there was inhalation injury. It occurred earlier. More respiratory complications, higher incidence of lung and cardiac failure as well as severe shock were observed. Moreover, hypoxemia and acidosis were found to be more severe in MOF patients with inhalation injury than those without. It is suggested that good control of inhalation injury and burn shock, as well as the ischemic-hypoxic damage of visceral tissues might be of great importance for the prevention and treatment of MOF in burn patients combined with inhalation injury.

Adult↗
PubMed1996

[The diagnosis and treatment of intracranial tuberculoma].

OBJECTIVE: To improve the level of diagnosis and treatment of intracranial tuberculoma. METHODS: Fourteen intracranial tuberculoma cases were hospitalized in the past five years, accounting for 0.9 per cent of the intracranial tumors in the same period. Five out of fourteen cases were treated conservatively while other nine were treated surgically. All the cases were received 6-month short-course anti-tuberculosis chemotherapy, among which only one case's treatment was prolonged to one year. RESULT: All the cases had good outcome, none of them dead. CONCLUSIONS: Operative indications of intracranial tuberculoma cases should be applied strictly. Good result could be gained via a short-course anti-tuberculosis chemotherapy, no matter operation was performed or not.

Adolescent↗
PubMed1996

[Relationship between c-erbB2 oncoprotein expression and biologic behavior of cervical squamous cell cancer].

OBJECTIVE: To investigate the relationship between c-erbB2 oncoprotein expression and biologic behavior and prognosis of cervical squamous cell cancer. METHOD: Immunohistochemistry was used to examine the c-erbB2 oncoprotein expression in 62 cases of cervical sequamous cell cancer, 9 cases of cervical iutraepithelical neoplasia (CIN) and 10 cases of normal epidermal tissues section of the cervix. RESULTS: Nineteen of 62 cancers and 1 of 9 cases of CIN showed positive staining. None of normal epithelium showed positive. In cervical cancer the positive staining rate of c-erbB2 oncoprotein in grade 1, 2 and 3 was 12.5%, 27.6% and 52.9% respectively. There was a significant difference between grade 1 + 2 and grade 3 (P = 0.019). In 20 cases operated on, 3 of 6 cases with positive staining had pelvic lymph node metastasis, while only 1 of 14 cases with negative staining had metastasis (P = 0.032). The 5-year survival rate of positive staining group was significantly lower than that of negative group (31.5% Vs 74.4%, P < 0.001). CONCLUSION: The c-erbB2 oncoprotein expression on cervical sequamous cell cancer was related to agressive biologic behavior and poor prognosis.

Adult↗
PubMed1996

[The effects of 3,4-dihydroxyacetophynone on the activity of nitric oxide synthetase in placental vascular endothelial cells and smooth muscle cells and on the level of endothelin-1 in plasma from pregnancy-induced hypertension patients].

OBJECTIVE: To observe the effects of 3,4-dihydroxyacetophynone (DHAP), one of the constituents of a traditional Chinese herbal medicine, on the activities of endothelial nitric oxide synthetase (NOS) in vascular endothelial cells (VEC) and vascular smooth muscle cells (VSMC) of placenta and the level of endothelin-1 (ET-1) in the plasma from PIH patients. METHOD: 22 nulliparous PIH patients were randomly divided into PIH group and DHAP treatment group. Each patients in DHAP group received intravenous administration of DHAP (160-240 mg/d). Blood samples were collected before the administration of DHAP and (or) before cesarean section. The placenta were assayed for nitric oxide synthase activity using histochemical analysis; the concentration of ET in plasma was measured by radioimmunoassays. 10 normal pregnant women or 10 nonpregnant women were served as controls. RESULTS: In normal pregnant controls, NOS activity was much higher than that in the PIH group; in DHAP group, there was some recovery of NOS activity after DHAP treatment. The concentration of ET was higher in PIH group than that of normal pregnant controls, but it decreased significantly after DHAP therapy (P < 0.05, vs PIH group or before DHAP therapy). CONCLUSION: This study indicates that DHAP is effective in the treatment of PIH and its mechanism of action may be due to the adjustment of NO/ET imbalance in PIH patients.

Acetophenones↗
PubMed1996

[An experimental study of regional spontaneous portasystemic shunt in cirrhotic rats].

CCl4 induced splenic portasystemic shunt (SPSS) was measured in 11 CCl4-induced cirrhotic rats and 10 controls, and mesenteric shunt (MPSS) was measured in 11 controls. 125I labeled albumin microspheres was used as nuclear markers for measurement of shunting rate. It was found that, portal resistance, free portal pressure, wedged hepatic venous pressure, portahepatic venous pressure gradient were all elevated markedly in cirrhotic rats, while the volume of portal flow had no significant difference between the two groups. SPSS and MPSS were higher remarkably those that in the normal controls, and SPSS was greater than MPSS significantly. It suggested that splenogastric venous bed is the main area for compensatory shunt and also the dangerous site of bleeding. Portaazygous disconnection is the operation of choice for control of bleeding. However it could impair the mechanism of spontaneous shunting compensation seriously. Disconnection operation combined with splenorenal shunt seems to be a reseasonable consideration.

Animals↗
PubMed1996

[Influence of Cordyceps sinensis (Berk.) Sacc. and rat serum containing same medicine on IL-1, IFN and TNF produced by rat Kupffer cells].

The results indicated that the levels of IL-1, IFN, and TNF, especially those of IL-1 and INF, produced by cultured rat kupffer cells were increased in the presence of Cordyceps sinensis (CS) or the drug serum (DS) from rats fed on CS. The experimental result of DS was similar to that of CS. However, the former had a better repeatability and stability.

Animals↗
PubMed1996

[Diagnosis and surgical management of pancreatic pseudocysts].

Fifty-two patients with pancreatic pseudocysts were treated surgically between 1968 and 1994. Clinical symptoms were non-specific. Ten patients with acute pancreatitis were managed conservatively and resolution occurred in 3 patients. 42 patients underwent operation. Internal drainage was performed in 28 patients, external drainage in 8, others in 6. Pancreatic fistulas occurred in the external drainage group, 2 patients died and 1 patient had the of recurred pseudocyst. There were no complications in the internal drainage group. It was quite different in the external drainage group. The management should differ in that acute and chronic pancreatic pseudocysts. Patients with pseudocysts of chronic pancreatitis could undergo emergent surgery of internal drainage because waiting 6 weeks for maturation of the pseudocysts after diagnosis was unnecessary and even hazardous. However, if pseudocyst developed after acute pancreatitis, it should be watched for up to 6-8 weeks. During this period the pseudocyst perhap disappeared spontanously or matured for surgery.

Adolescent↗
PubMed1996

Cloning and expression of full-length delta-endotoxin cryIA(c) gene in three kinds of prokaryotic systems using shuttle vector pHT3101.

Two fragments, 6.5kb and 4.3kb encoding 5' end and 3' end of delta-endotoxin cryIA(c) gene, respectively, were selected from the Bacillus thuringiensis kurstaki-HD-73 75kb plasmid gene pool using random primer labelling delta-endotoxin cryIA(b) gene probe. The full-length 3.92kb cryIA(c) gene including 5' end 152 bp promoter sequence and 3' end 198 bp terminater sequence was rebuilt after uncoding sequences were deleted. Three kinds of engineering strains harbouring the same recombinant plasmid pHTY1 were obtained after the cryIA(c) gene had been subcloned in shuttle vector pHT3101 and transformed to E. coli NM522, Bacillus subtilis AS1176 and Bacillus thuringiensis crystal-deficient 4D10(H3ab). SDS-PAGE electrophoresis patterns reveal that the cryIA(c) gene expressed the same 133,300 protoxin proteins in all three host systems with the same molecular weight to the crystal protein from the Bacillus thuringiensis kurstaki HD-73. Immuno-assays indicate that the expression proteins can react with antiserum of HD-73 paraspore crystal protein in the same pattern as the natural crystalprotein. Bioassays using crude expressed products from three host strains reveal that they all showed toxicities to second instar larvae of Plutella xylostella, and their LD50 were calculated to be 0.311 micrograms/cm2, 0.02 micrograms/cm2 and 0.017 micrograms/cm2, respectively.

Bacillus subtilis↗
PubMed1996

[Regulation of purine biosynthetic genes expression in Salmonella typhimurium. V. Nucleotide sequences evidence without purJ gene].

Previous genetic analysis showed that AICAI transformylase, IMP cyclohydrolase and GAR synthetase are encoded by purJ, purH and purD respectively, and which constitute a operon, mapped on 90 min in genetic map of Salmonella typhimurium But recent study in E. coli indicated that the genes encoding for above three enzymes only have purH and purD, without purJ gene. Report here is the DNA sequences evidence for abence of purJ gene in Salmonella typhimurium.

Escherichia coli↗
PubMed1996

[Effects of ATP on intracellular free [Ca2+]i in isolated cochlear OHC].

The effect of adenosine triphosphate (ATP) upon intracellular free calcium concentration ([Ca2+]i) of cochlear outer hair cell (OHC) isolated from guinea pigs was studied. Stained with fluorescence, [CA2+]i was measured using ACAS 570. ATP significantly increased the [Ca2+]i level, which then dropped rapidly from the peak value it rose again reaction after readdtion of ATP. This result indicates that ATP is a nerve transmitter acting on the outer hair cells.

Adenosine Triphosphate↗
PubMed1995

Cloning of the Schizosaccharomyces pombe gene encoding diadenosine 5',5"'-P1,P4-tetraphosphate (Ap4A) asymmetrical hydrolase: sequence similarity with the histidine triad (HIT) protein family.

Diadenosine 5',5"'-P1,P4-tetraphosphate (Ap4A) asymmetric hydrolase (EC 3.6.1.17) is a specific catabolic enzyme of Ap4A found in Schizosaccharomyces pombe. We have previously described the partial purification of Ap4A hydrolase from S. pombe [Robinson, de la Peña and Barnes (1993) Biochim. Biophys. Acta 1161, 139-148]. We determined the sequence of the N-terminal 20 amino acids of Ap4A hydrolase and designed two degenerate PCR primers based on the sequence. The 60 bp DNA fragment obtained by PCR, which is specific to Ap4A hydrolase, was used to isolate the Ap4A hydrolase gene, aph1, from S. pombe by screening a genomic DNA library in a multicopy plasmid. Ap4A hydrolase activity from the crude supernatant of a positive S. pombe transformant was about 25-fold higher than the control. There was no detectable stimulation of enzymic activity by phosphate. The aph1 gene from S. pombe contains three introns. The intron boundaries were confirmed by sequencing the cDNA of the aph1 gene from a S. pombe cDNA library. The deduced open reading frame of the aph1 gene codes for 182 amino acids. Two regions of significant local similarity were identified between the Ap4A hydrolase and the histidine triad (HIT) protein family [Séraphin (1992) DNA Sequence 3, 177-179]. HIT proteins are present in prokaryotes, yeast, plants and mammals. Their functions are unknown, except that the bovine protein inhibits protein kinase C in vitro. All four histidine residues which are conserved among the HIT proteins, including the HxHxH putative Zn(2+)-binding motif, are conserved in the Ap4A hydrolase. In addition, there are two regions of similarity between the Ap4A phosphorylases I and II from Saccharomyces cerevisiae and Ap4A hydrolase from S. pombe. These regions overlap with the HIT protein similarity regions. The aph1 gene from S. pombe is the first asymmetrical Ap4A hydrolase gene to be cloned and sequenced.

Acid Anhydride Hydrolases↗
PubMed1995

Control of cell fate by a deubiquitinating enzyme encoded by the fat facets gene.

Ubiquitin is a highly conserved polypeptide found in all eukaryotes. The major function of ubiquitin is to target proteins for complete or partial degradation by a multisubunit protein complex called the proteasome. Here, the Drosophila fat facets gene, which is required for the appropriate determination of particular cells in the fly eye, was shown to encode a ubiquitin-specific protease (Ubp), an enzyme that cleaves ubiquitin from ubiquitin-protein conjugates. The Fat facets protein (FAF) acts as a regulatory Ubp that prevents degradation of its substrate by the proteasome. Flies bearing fat facets gene mutations were used to show that a Ubp is cell type--and substrate-specific and a regulator of cell fate decisions in a multicellular organism.

Amino Acid Sequence↗
PubMed1995

A novel insertional mutation in the TC21 gene activates its transforming activity in a human leiomyosarcoma cell line.

TC21 is the fourth member of the ras gene family to exhibit oncogenic activation in human tumor cells. To assess the prevalence of activated TC21 oncogenes in human tumors, we have developed sensitive single-strand conformational polymorphism (SSCP) conditions and immunological reagents for the detection of both single base alterations and/or overt overexpression in a wide spectrum of human tumor cell lines and surgical samples. In an initial examination of 33 human tumor specimens, we observed a novel nine basepair three amino acids insertion at TC21 codon 24 in one human uterine leiomyosarcoma cell line, SK-UT-1. This mutant allele when transfected into NIH3T3 cells, displayed high transforming activity comparable to that of the Leu72 oncogenic mutant identified by expression cDNA cloning from a human ovarian carcinoma cell line. Comparing the level of GTP-binding by the mutant and normal TC21 products revealed that this novel lesion increases the GTP-bound form of the TC21 molecule. These findings imply that the mechanism by which mutations activate the oncogenic properties of this ras-related molecule is analogous to that of previously known ras family members.

3T3 Cells↗
PubMed1995

Interleukin-6 down-regulates expressions of the aldolase B and albumin genes through a pathway involving the activation of tyrosine kinase.

Interleukin-6 plays a key role in mediating acute-phase protein synthesis in hepatocytes. However, the mechanism of how interleukin-6 regulates aldolase B and albumin syntheses in hepatocytes is not completely understood. In this study, using primary cultured rat hepatocytes, we have shown that interleukin-6 down-regulates expressions of the aldolase B and albumin genes in a dose- and time-dependent manner. We examined whether the decrease in aldolase B and albumin mRNA expressions by interleukin-6 reflected transcriptional down-regulation or stability of the mRNA. Actinomycin D and cycloheximide did not affect the interleukin-6-mediated decrease in the expressions of both genes. These results suggest that the decreased expressions of both genes induced by interleukin-6 is controlled at the transcriptional level, and that it is due neither to increased degradation of mRNA nor to synthesis of new proteins. Protein kinases play a fundamental role in the intracellular signal transduction. To examine the interleukin-6 signal pathway(s) leading to the decrease of aldolase B and albumin mRNA expressions, we tested various kinds of protein kinase inhibitors in this system. Herbimycin A, an inhibitor of tyrosine kinase(s), prevented the decrease in the expression of aldolase B and albumin mRNAs by interleukin-6. H-7, an inhibitor of protein kinase C, prevented the decrease in the expression of albumin mRNA by interleukin-6, but did not induce recovery of that of aldolase B mRNA. These results suggest that a tyrosine kinase(s) or a herbimycin A-sensitive kinase(s) constitutes a common pathway for interleukin-6-mediated reduction of aldolase B and albumin mRNA expressions and that distinct pathways exist for the modes of expression of the two mRNAs.

Albumins↗
PubMed1995

4-Aminopyridine-induced phasic contractions in rat caudal epididymis are mediated through release of noradrenaline.

4-Aminopyridine, a K+ channel blocker, evoked phasic contractions in the caudal duct of the rat epididymis. The 4-aminopyridine-induced contractile response was either inhibited or prevented by the alpha 1-adrenoceptor antagonists, prazosin (IC50 = 2.7 nM) and benoxathian (IC50 = 14.6 nM). Blockers (1 microM) of alpha 2-adrenoceptors and purinoceptors but not of beta-adrenoceptors or muscarinic receptors caused a small but statistically significant reduction of the 4-aminopyridine-induced response. 4-Aminopyridine lost its ability to induce contractions after noradrenergic nerves had been destroyed by 6-hydroxydopamine. In addition, protriptyline and xylamine, blockers of noradrenaline uptake, also inhibited the 4-aminopyridine-induced contractile response. However, other putative K+ channel blockers (tetraethylammonium ion, quinine, quinidine and glibenclamide) did not cause the muscle to contract. These findings demonstrate that the 4-aminopyridine-induced release of noradrenaline and adenosine 5'-triphosphate as co-transmitters results from membrane depolarization due to 4-aminopyridine blockade of K+ channels in noradrenergic nerve terminals. The 4-aminopyridine-sensitive K+ channels might thus play a physiological role in regulating the nerve membrane potential and neurotransmission in the rat caudal epididymis.

4-Aminopyridine↗