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Biomedical subjects

X Yang

Publications and source records attributed to X Yang.

At least 253 records · Page 14Linked to original sources
PubMed2001

Angiotensin II type 1 receptor modulation of L-type calcium currents in guinea-pig ventricular cells.

OBJECTIVE: To study the cellular mechanism of the effect of Ang II on ICa,L in single guinea-pig ventricular cells by using losartan and 1-(5-lsoquinolinylsulfonyl)-2-Methyl-Piperazine (H-7) as the Ang II type 1 receptor (AT1) inhibitor and protein kinase C inhibitor, respectively. METHODS: Patch clamp techniques were used to study the cellular mechanism of the effect of Ang II on ICa,L in single guinea-pig ventricular cells. RESULTS: In the whole cell patch clamp recording model, Ang II stimulated ICa,L in a concentration dependent manner; the maximal effect was obtained at 100 nmol/L (n = 9). At 30 nmol/L, Ang II stimulated peak ICa,L from 11.3 +/- 0.6 pA/pF to 15.3 +/- 0.6 pA/pF (at + 10 mV, n = 9, P < 0.05). 100 nmol/L Losartan, a specific AT1 receptor inhibitor, had no effect on ICa,L (n = 9), but the effect of Ang II on ICa,L was inhibited by 100 nmol/L Losartan. Ang II on ICa,L was also inhibited by 20 mumol/L H-7, a specific protein kinase C inhibitor, whereas H-7 alone has no effect on ICa,L (n = 9). CONCLUSION: Ang II stimulates ICa,L in guinea-pig ventricular cells by binding to AT1 through a transduction pathway involving protein kinase C.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2001

[Preparation and analysis of pure type II collagen from porcine articular cartilage].

This investigation was aimed at the preparation of pure type II collagen from porcine articular cartilage and the feasible method for producing type II collagen in bulk. After dispersal of the porcine articular cartilage, the proteoglycans were extracted by guanidinium hydrochloride and dissolved by pepsin in acid solvent. The contaminants including denatured and degraded protein and other collagen was removed via the repeated procedure of purification. For obtaining the purer type II collagen, the chromatography with sepharose H. P. Column was also used. The purity of the sample was compared with the type II collagen produced by Sigma Company. Both type II collagens were characterized by SDS-PAGE electrophoresis, amino acid analysis and maximal violet chromatography, and all of the results accorded with the standard photograph in the references. The purity of the sample was higher than that of the product of Sigma Company. This prepared collagen of type II is a product of high purity. The raw materials are the common porcine articular cartilage, which is rich in resource and low in cost. Therefore, it is suitable to produce type II collagen in batches.

Amino Acids↗
PubMed2001

[The diagnostic value and limitations of total serum bile acid determined enzymatically].

OBJECTIVE: To elucidate the diagnostic value of total serum bile acid. METHOD: Clinical data from 913 cases was statistically analyzed with SPSS for Windows and other statistical procedures reported previously. RESULTS: (1) The mean of TBA of healthy subjects was (4.0 +/- 3.2) micromol/L. The TBA level of liver disease group is significantly higher than other group(P < 0.01). (2) The mean of TBA of patients with acute hepatitis was (167.2 +/- 132.4) micromol/L, the highest value was 449.5 micromol/L, it was significantly higher than other groups. TBA was a sensitive mark reflecting acute hepatic injury. (3) The sensitivity of TBA in patients with cirrhosis was 85.8%, higher than routine liver function tests. TBA is a valuable mark reflecting collateral circulation. (4) The sensitivity of TBA in mild chronic hepatitis was only 30.5%, much lower than ALT and TBIL (P < 0.01). (4) There was a relationship between the level of TBA and the severity of patients' condition, but the value of TBA for evaluating the severity was not as good as TBIL. CONCLUSION: The specificity of TBA is quite high, the sensitivity is moderate, TBA is valuable for the diagnosis of liver disease, especially for acute hepatitis and cirrhosis, but it's sensitivity for mild chronic hepatitis is only 30.5%, it is not as good as TBIL for evaluating the condition of patients.

Acute Disease↗
PubMed2001

[Appraisal of renal failure reversing therapies in lupus nephritis].

OBJECTIVE: This study aimed to explore the therapies of reversing renal failure in lupus nephritis. METHODS: The research strategy was a retrospective cohort study. 173 patients were included in the study. All of them were consecutive in-patients of newly diagnosed renal failure (serum creatinine > 180 micromol/L) with lupus nephritis from 1991 to 1999 in the university hospital. The research factors included steroids, cyclophosphamide and cyclosporin. Steroids were divided to oral prednisone, intravenous dexamethasone and intravenous methylprednisolone pulse; cyclophosphamide dose intensity was divided into three grades: none, low dose (average dose 0.25 g/m(2) body surface area per week). 51 demographic, clinical and laboratory data were included in the study as possible confounding factors. The study end-point was recovery of renal function that was defined as a level of serum creatinine <or= 116 micromol/L in the azotemia patients or a 50% reduction of serum creatinine and discontinuation of dialysis in the uremic patients. The improvement had to be maintained for at least three months. Collection of the study factors and outcome variable was conducted by two separate, blinded groups of clinical specialists with two structured abstracting forms. RESULTS: The number of complete following up patients was 142 (82.1%). After over 6 months of following up, 93 cases (65.5%) recovered their renal function and 17 cases (12.0%) died. In COX proportional hazard regression model, cyclophosphamide therapy was significantly associated with the recovery of renal function. The adjusted hazard ratio (HR) to recovery of renal function was 4.41, 95% CI = 1.03 - 18.94 in low dose; and the HR was 13.29, 95% CI = 3.11 - 56.82 in high dose cyclophosphamide therapy. The gender, duration of renal dysfunction, small renal size, severe anemia and serum creatinine were also significantly associated with renal function recovery. Cyclophosphamide therapy was not significantly associated with death. The variables associated with death were low level of serum albumin and edema. CONCLUSION: Cyclophosphamide pulse was an efficient therapy in reversing renal failure of lupus nephritis, especially in the patients with short duration of renal failure, non-small in renal size, and non-severe anemia.

Administration, Oral↗
PubMed2001

[Cerebral watershed infarcts].

OBJECTIVE: To investigate the clinical types and characteristics of cerebral watershed infarcts (CWI). METHODS: Analysis of the clinical data and imaging characteristics of 192 cases with CWI confirmed by CT scan or MRI. RESULTS: In 69 cases (35.9%), CWI appeared as wedge-shaped areas on CT scan or MRI, the infarcts located at marginal zones between the anterior and middle cerebral arteries and were usually associated clinically with hemiparesis, transcortical motor aphasia and dementia. In 74 cases (38.5%) the infarcts also appeared as wedge-shaped areas on CT scan and MRI, but located at marginal zones between the middle and posterior cerebral arteries, the patients mainly showed mild hemiparesis and apathy. In 49 cases (25.5%), the long-line or triangle-shaped infarct areas usually located at marginal zones between the superficial and deep territory of the middle cerebral arteries in the basal ganglia and posterolateral angulus frontalis. CONCLUSION: The presentation of CWI is complicated, and the diagnosis of that mainly depends on imaging studies such as CT scan and MRI.

Adult↗
PubMed2001

[A study of survival motor neuron and neuronal apoptosis inhibitory protein gene in spinal muscular atrophy].

OBJECTIVE: To study the absence of survival motor neuron(SMN) gene exon 7,8 and neuronal apoptosis inhibitory protein(NAIP) gene exon 5,6 in Chinese patients with type I - IV spinal muscular atrophy (SMA) and to confirm the relationship between the deletions of SMN, NAIP and SMA phenotype. METHODS: PCR and PCR-enzyme methods were used to detect the deletions of NAIP gene exon 5,6 and SMN gene exon 7,8 in 45 SMA (I - IV) patients and 30 healthy relatives of the patients and 30 normal controls. RESULTS: Deletions of exon 7 and 8 of the telomeric SMN gene were 4/4, 2/3, 1/8 and 0/30 in type I, II, III and IV SMA patients, respectively. One patient with type II lacked the exon 7 but retained exon 8. No deletions was found in the relatives and controls(0/60). No deletions of exon 5 and 6 of the NAIP gene was detected in all the patients, healthy relatives and controls. CONCLUSIONS: Deletions of SMN gene exon 7 and 8 exa mined by PCR-enzyme digestion could be recommended as an accurate gene diagnostic method for SMA with type I and II. However, the method was not as useful in type III as in I and II for making a diagnosis of SMA. Type IV SMA, a heterogeneous disease with phenotypical similarities to type I - III SMA, may be caused by deletion of other genes. The frequency of NAIP deletion was lower in Chinese SMA patients.

Child↗
PubMed2001

[The surgical treatment for cerebellopontine angle meningioma].

OBJECTIVE: To discuss the risks and benefits of the surgical treatment for cerebellopontine angle meningioma. METHODS: Eighty-eight patients with cerebellopontine angle meningioma treated surgically in the last twenty years were analyzed retrospectively. All patients were followed up from six months to eleven years. RESULTS: Complete resection was done in 68 (77.3%) patients and subtotal resection in the rest 20 patients. Six(6.8%) patients died after the operation. Follow up showed that eight (13.3%) patients died and six (10%) patients developed recurrence. CONCLUSION: Surgery is the treatment of choice for cerebellopontine angle meningioma. It is the key to rationally choose the adequate approach, carefully manage and protect the vessels, nerves, brain stem and to institute timely and rationally the auxiliary therapy for the postoperative complications in order to increase the efficacy and improve the patients' quality of life.

Adolescent↗
PubMed2001

[Study on variation and interrelations of characteristics at ginseng germplasms].

The variation and interrelations of some characteristics of Panax ginseng germplasms(lines), which were five selfmating generations of some single plants were studied. Methods of multivariate analysis, such as correlation, regression, or clustering, and coefficient of variation were used. The results were of benefit to the breeding and standardized planting of Panax ginseng.

Genetic Variation↗
PubMed2001

Prospective survey on neurosurgical intensive care for patients with severe head injury.

OBJECTIVE: To prospectively compare the clinical outcome of intensive care therapy (ICT) with that of conventional care therapy (CCT) in severe head injured patients. METHODS: Patients with severe head injury were assigned randomly into Group ICT and Group CCT, 100 patients in each group. Patients in Group ICT accepted intensive care therapy in neurosurgical intensive care (NIC) unit for the first 2 weeks after admission, while patients in Group CCT accepted conventional care therapy in ordinary ward. The outcomes were evaluated 3 months after injury. RESULTS: There was a significant increase in good recovery (54%) (chi(2)=4.43, P<0.05) and significant decrease of death (25%) (chi(2)=4.50, P<0.05) in Group ICT compared to 39% and 39% in Group CCT respectively. The differences were also confirmed statistically in the following aspects: the patients under 50 years with good recovery pronounced a number increase (chi(2)=7.54, P<0.01), while the mortality in the same range of age was decreased in Group ICT (chi(2)=5.28, P<0.05). The mortality was reduced significantly in patients with GCS for 6-8 on admission (chi(2)=8.47, P<0.01) and in patients with the level of brain stem injured below mesencephalon (chi(2)=4.15, P<0.05). ICT would improve the outcome in patients undergoing conservative therapy only (chi(2)=13.13, P<0.01). CONCLUSIONS: NIC plays an important role in assessing the neurological state, guiding management, evaluating curative effect and estimating the outcome.

Adolescent↗
PubMed2001

[The scleral buckling combined with argon laser photocoagulation for retinal detachment].

OBJECTIVE: To investigate the effects and indications of postoperative photocoagulation with argon laser instead of intraoperative cryotherapy for closing the retinal breaks during the scleral buckling operation in rhegmatogenous retinal detachment (RD) METHODS: An analysis of clinical data in 35 RD cases (38 eyes) was conducted retrospectively. These cases were treated by argon laser photocoagulation after the scleral buckling surgery from December, 1999 to April, 2000 in our hospital. RESULTS: Thirty-eight eyes were followed-up from 3 to 6 months. In 36 of 38 eyes, the retina was reattached after surgery (94.7%). Postoperatively, thirty-one eyes (86. 1%) had a visual acuity (VA) of >or= 0.05 and the best VA was 1.0. CONCLUSIONS: The method using postoperative photocoagulation instead of cryotherapy during scleral buckling surgery can simplify the surgical manipulations, alleviate the vessel damage of the retina and uvea and reduce the postoperative complications. It is a practicable way to treat RD. Surely, photocoagulation can not totally replace cryotherapy. Proper selection of indications and avoidance of complications of photocoagulation can elevate the successful rate of reattachment of RD, and promote the recovery of visual function.

Adolescent↗
PubMed2001

[Chromosome t (8; 21) and t (15; 17) in a patient with acute myeloid leukemia].

OBJECTIVE: To report an acute myeloid leukemia (AML) patient with both chromosome t (8; 21) and t (15; 17). METHODS: Chromosome specimen was prepared by short-term culture of bone marrow cells, karyotype analyses by R-banding technique, and fusion genes by reverse transcriptase-polymerase chain reaction (RT-PCR). RESULT: Karyotype analyses showed the appearance of 45, X, -X, t (8; 21), t (15; 17), and RT-PCR assay revealed AML1/ETO and PML-RARalpha fusion gene transcripts. CONCLUSION: AML with both t (8; 21) and t (15; 17) might be recognized as a a novel subtype of acute leukemias.

Bone Marrow Cells↗
PubMed2001

[Clinical study of P-gp, and bcl-2 protein expression in non-Hodgkin's lymphomas patients].

OBJECTIVE: To investigate the relationship between the expression of P-gp, P26-bcl-2 and the prognosis in intermediate and high grade non-Hodgkin's lymphomas (NHL). METHODS: Sixty cases of intermediate and high grade NHL were retrospectively reviewed using immunohistochemical method. All patients were received CHOP chemotherapy over 4 courses. RESULTS: P-gp was identified in 15 and P26-bcl-2 in 25 cases. The 3-year survival rates for patients with P26-bcl-2 (+) and P26-bcl-2 (-) were 37.64% and 76.80%, respectively (P < 0.005), and for patients with both positive P-gp and P26-bcl-2 and both negative were 15.38% and 48.48%, respectively (P = 0.038). CONCLUSIONS: There is direct relationship between the P-gp, P26-bcl-2 protein expression and the prognosis in intermediate and high grade non-Hodgkin's lymphoma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

[Eukaryotic expression, purification and analysis of the fusion protein of Epo-Tpo(C)].

OBJECTIVE: To further elucidate the function of Tpo(C) and create a new type of Epo. METHODS: Tpo(C) was linked to Epo to produce a fusion protein--Epo-Tpo(C). The fusion gene was expressed in CHO cell. After selection with G418, Epo-Tpo(C)-expressing cell lines was obtained. The supernatant had 15 U/ml Epo activity. The results of PCR and Southern Blotting indicated the fusion gene was fused into the genome. RT-PCR and RNA Dot Blotting analysis found the Epo-Tpo(C) mRNA. The supernatant was purified with Blue-Sepharose CL-6B. RESULTS: The rate of recovery was 94%. The in vivo activity tested by reticulocytes was 20% higher than ELISA. The half-life was about 12 hours while the Epo standard sample had half-life of 8 hours tested with ELISA in rat. CONCLUSION: The results proved that Tpo(C) could protect Epo and improve its function. The fusion protein had satisfactory effect in the model of rat renal failure.

Animals↗
PubMed2001

[Prospective study of combination of interferon-alpha with ribavirin for treatment of chronic hepatitis C in children].

OBJECTIVE: To explore more efficacious therapy for chronic hepatitis C in children. METHODS: With combination of recombinant interferon-alpha/ribavirin therapy, we treated 15 children, with viral sera and biopsy-proven chronic hepatitis C, who did not respond to the treatment of interferon-alpha alone and had frequently relapse, with the disease courses of 5-9 years (mean 4.5 years). Mean age of the children (12 males and 3 females) was 6.8 years (6 months-10 years). 14 patients had blood transfusion history. RESULTS: HCV RNA in 12 patients was negative after combined treatment of 3 months (1.5-5 months). None of the patients treated had skin rash and severe adverse reaction. Transient fever and influenza-like symptoms with combined therapy were similar to those with interferon-alpha therapy alone. Hemoglobin level decreased slightly in 9 patients (mean decrease by 5 g/L; max, 20 g/L). Reticulocytes elevated slightly. White blood cells, platelets, Bun and Cr were normal in all the patients. CONCLUSION: Our results show that combination of interferon-alpha with ribavirin for treatment of hepatitis C in children is efficacious, safe and reliable. It deserves popularization.

Antiviral Agents↗
PubMed2001

[A study of on the transport of neurotrophin-4 in facial nerve].

OBJECTIVE: This is a study on the transport information of neurotrophin-4 (NT-4) in facial nerve using radioactive tracer technique. METHODS: After one lateral facial nerve trunk of adult rabbit was transected, a silicone chamber was inserted between the stumps, and 7.4 MBq of 131I-NT-4 was administered into the chamber. At the distinct moment of post-injection, the head of one rabbit was imaged at coronary position, the bilateral facial nerve trunk and brain-stem of the others were collected and counted respectively. After 1 mg of brain-derived neurotrophic factor (BDNF) and 7.4 MBq of 131I-NT-4 were administered into the chamber of one rabbit, the rabbit was imaged at coronary position of head at distinct moment. RESULTS: 5.08% of 131I-NT-4 was transported into facial nerve trunk at 4 h of post-injection. 131I-NT-4 presented high peak in facial nerve trunk during the period of 8, 12 h, the peak values were 20.58% and 22.74% respectively. 34.75% and 45.57% of 131I-NT-4 were transported into the brain-stem of experimental side at 8 h and 12 h respectively. The transport of 131I-NT-4 was markedly restrained by BDNF in facial nerve. CONCLUSION: NT-4 displays a receptor-mediated retrograde transport in facial nerve.

Animals↗
PubMed2001

[Pilot study on mutations of p53 gene in laryngeal carcinoma].

OBJECTIVE: To determine the characteristic and frequency of the point mutation of p53 gene. METHODS: 22 cases of laryngeal squamous cell carcinoma (LSCC) with positive expression of mutant p53 protein and 2 cases of normal laryngeal epithelium as control were examined by means of polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP), single strand conformation polymorphism (SSCP) and DNA sequencing analyses. RESULTS: 3 cases of LSCC had the point mutation on codons 248, 250 and 254 of exon 7 in p53 gene. None of the cases had the point mutation on codon 249. CONCLUSION: These findings suggest that the point mutation on codon 249 of exon 7 in p53 gene may be uncommon in LSCC. SSCP and DNA sequencing analyses are sensitive and rapid methods for detecting p53 gene mutation.

Adult↗