Biomedical subjects
Publications and source records attributed to X Yang.
A computer program for computing the free Ca2+ concentration in the experimental solution containing multiple metals and ligands used for the experimentals of myofibrillar AT-Pase or skinned muscle cell is presented. This program is convenient and accurate.
To investigate the acute effects of platelet activating factor (PAF) on pulmonary circulation and cardiovascular function in rats, twenty anesthetized Wistar rats were given 100-800 ng/kg PAF by bolus intrapulmonary artery infusion. Mean pulmonary artery pressure (mPAP), mean systemic artery pressure (mSAP) and cardiac output (CO) were measured before and after administration. The results showed that PAF infusion caused: a rise in mPAP from 2.11 +/- 0.20 kPa to 2.65 +/- 0.11 kPa (100 ng/kg, P > 0.05), from 2.32 +/- 0.25 kPa to 2.85 +/- 0.24 kPa (200 ng/kg, P < 0.05) and from 2.11 +/- 0.33 kPa to 3.01 +/- 0.45 kPa (400 ng/kg, P < 0.05)p; a down in mSAP from 16.0 +/- 2.11 kPa to 9.1 +/- 2.39 kPa (100 ng/kg, P < 0.05); from 16.3 +/- 1.38 kPa to 7.0 +/- 0.57 kPa (200 ng/kg, P < 0.05) and from 16.4 +/- 2.56 kPa to 6.3 +/- 0.89 kPa (400 ng/kg, P < 0.05); and a down in CO from 48.1 +/- 2.16 ml/min to 30.8 +/- 3.27 ml/min (100 ng/kg, P < 0.05), from 47.8 +/- 2.12 ml/min to 25.6 +/- 2.86 ml/min (200 ng/kg, P < 0.05) and from 48.3 +/- 2.24 ml/min to 20.0 +/- 2.39 ml/min (400 ng/kg, P < 0.05). These findings suggested that PAF play an important role in the pathophysiologic course of pulmonary hypertension.
Twenty patients with surgically and pathologically confirmed gynecologic cancer from December, 1991 to December, 1992 were treated by intraperitoneal (i.p.) chemotherapy with carboplatin in 15 and by intravenous (i.v.) chemotherapy with carboplatin in 5, patients had normal hepatic and renal function test and were nonsmoker. Using Grathite atomic absorption spectrum method, total mean maximal plasmic carboplatin concentration in the cases by intravenous infusion was 8 times greater than those by intraperitoneal infusion. The half-life of plasmic elimination in the cases treated by i.v. infusion and by i.p. infusion were respectively 10.82 +/- 4.95 hours and 54.04 +/- 10.75 hours (P < 0.05). But total carboplatin plasmic clearance in the cases were 1.88 +/- 0.53 ml/min and 1.12 +/- 0.58 ml/min, respectively (P < 0.05). Pharmacokinetic profiles suggest a possible therapeutic advantage by giving the drug intraperitoneally for the treatment of tumour nodules situated in the peritoneum. This research also suggest the method has the possibility in increasing antitumn effect and decreasing bone marrow in intoxication because of the wide distribution, low plasmic concentration and slow clearance of drugs.
Through catheter on uterine artery digital subtractive angiography (DSA) intraarterial infusion of chemotherapeutic agents for the treatment of malignant trophoblastic diseases can raise local drug concentration, improve therapeutic results and reduce general side-effects. But mural thrombosis, a possible complication of intra arterial catheterization, should not be overlooked. This study reports 2 cases of mural thrombosis complication in selective pelvic artery catheterization for chemotherapy. The incidence, relevant factors to its occurrence such as technique of catheterization and the duration of catheter retention, as well as measures of prevention and treatment of mural thrombosis are discussed together with review of literature. With regards to prevention of mural thrombosis, stress is being laid on the importance of the technique of catheterization. Preliminary comments on the problem of heparin administration as a preventive measure of mural thrombosis are made.
An experimental study on the damage and regeneration of the corneal sensory nerves in rabbit eyes with herpes simplex keratitis (HSK) was carried out by means of acetylcholine esterase staining and transmission electron microscopy. The results indicate that the diminution of the corneal sensitivity detected clinically in HSK is caused by the damage of the terminals of the sensory nerve plexus in the epithelial and subepithelial layers of the cornea and in the later stage of HSK, the corneal sensory nerves begin to regenerate, that is the basis of the restoration of corneal sensitivity.
21 patients (mandibular prognathism = 11, mandibular retrognathism = 10) whose occlusal force and masticatory efficiency were measured and analysed preoperatively, three and six months following sagittal split ramus osteotomy. The result shows that, in individuals with mandibular retrognathism treated by lengthening of the mandible, the occlusal force and masticatory efficiency would decrease, in individuals with mandibular prognathism treated by reduction in mandibular length, the occlusal force and masticatory efficiency would increase. There is no linear correlation relationship between the change of the occlusal force and the movement of the angle and the distance of the mandible.
It is difficult to make a precise diagnosis of intestinal tuberculosis and to differentiate it from Crohn's disease. For evaluating Polymerase Chain Reaction (PCR) assay in these two aspects, 36 specimens of intestinal tuberculosis from surgical resections and endoscopic biopsies and 26 Crohn's disease samples were subjected to PCR assay. 21 specimens of normal colon tissue surrounding cancer were used as the control. Oligonucleotides derived from the IS 6110 sequence, which is repeated in M. tuberculosis chromosome and highly specific for the M. tuberculosis complex, were used as a primer. The amplified PCR products were detected by examination of ethidium-bromide-stained polyacrylamide gels. The specificity of PCR products was confirmed by digestion with Sal I restrictive endonuclease and southern blot hybridization using digoxigenin-labeled probe. The results showed that the M. tuberculosis DNA was identified in 27/36 intestinal tuberculosis, but none of 26 Crohn's disease. Acid fast bacilli were only found in 16/36 intestinal tuberculosis. In conclusion, as a rapid, sensitive, and specific pathogenic method in diagnosis of intestinal tuberculosis, PCR assay has been developed in this study, and is considered valuable in the differentiation between intestinal tuberculosis and Crohn's disease.
Myxoid liposarcoma and malignant fibrous histiocytoma (MFH) are common soft tissue sarcomas of adulthood. Histopathologically they often show intratumor heterogeneity. In some cases, differential diagnosis of liposarcoma and MFH is difficult. It has been reported that myxoid liposarcomas are characterized by chromosomal translocation t (12; 16) (q13; p11), and that this results in two types (type I and type II) of FUS/TLS-CHOP fusion transcripts. In this study, the FUS/TLS-CHOP chimeric transcripts in seven malignant soft tissue tumors of Asian patients were analyzed by reverse transcription-polymerase chain reaction, DNA blot hybridization and nucleotide sequencing. One myxoid liposarcoma and two round cell liposarcomas possessed a chimeric transcript whose fusion point was the same as that of the type I fusion transcript reported previously for myxoid liposarcoma. We were thus able to detect the type I FUS/TLS-CHOP fusion transcript in clinical specimens of liposarcoma from Asian patients, including the first examples of round cell liposarcoma. These results suggest that the detection of FUS/TLS-CHOP chimeric transcripts or chimeric genes can be used as a diagnostic tool for the pathological diagnosis of liposarcomas.
To examine the impact of the underlying defective platelet mechanism on the response to 1-desamino-8-D-arginine vasopressin (DDAVP, Desmopressin), we studied the effect of intravenous infusion of 0.3 microgram/kg of DDAVP in a randomized double blind placebo-controlled trial with cross-over in 18 carefully characterized patients with congenital platelet defects (CPD) and BT > or = 9 min. Eleven patients had normal dense granule stores and normal thromboxane A2 (TxA2) production (Group I), 3 patients had normal granule stores but impaired TxA2 production (Group II), and 4 had delta-storage pool deficiency (Group III). DDAVP shortened BT at 50 min (DDAVP 14.6 +/- 2.2 vs placebo 19.6 +/- 2.3 min; n = 18; mean +/- SE; p = 0.003) and 4 h (17.0 +/- 2.2 vs 19.6 +/- 2.1 min, p = 0.055), and raised plasma FVIIIC and von Willebrand factor (vWF). At 50 min DDAVP shortened BT by > or = 5 min in 8 of 11 Group I patients (mean 9.7 +/- 1.3 vs 16.3 +/- 2.8 min; p < 0.008), 1 of 3 Group II patients (11.9 +/- 3.9 vs 17.7 +/- 6.6; p = NS) and none of Group III patients (mean 30 min both arms). Ten patients (Group I or II) were managed successfully during surgical procedures with DDAVP alone. We conclude that DDAVP shortens BT in majority of CPD patients with normal dense granule stores and suggest that BT response may be dependent on the underlying platelet defect. DDAVP is a useful modality in management of selected patients, particularly those with normal dense granule stores.
Twenty-six patients with obstructive jaundice were investigated for RBC immune function. It was found that C3b receptor's E rosette forming rate in jaundiced patients was significantly lower than that of nonjaundiced patients, and the C3b receptor's E rosette forming inhibitory rate was higher than that of nonjaundiced patients. The RBC immune function disturbance may contribute to the postoperative sepsis in jaundiced patients.
Luminol-hemin-H2O2 system was used for chemiluminescent flow injection analysis with immobilized luminol to determine hydrogen peroxide. The flow injection system was simplified. The method is fast and sensitive, and it has a dynamic range of detection from 1.0 x 10(-9) to 5.0 x 10(-4) mol/L with the detection limit of 2.6 x 10(-11) mol/L for H2O2.
The changes of the structure, content and anion transport function as well as the blood gases and electrolytes inside and outside the erythrocytes were investigated in 3 groups of subjects: type I respiratory failure patients (group 1, n = 40); type II respiratory failure patients (group 2, n = 40) and controls (group 3, n = 37). The results showed that (1) anion transport function impairment of erythrocyte membrane band 3 protein and HCO3-/Cl- exchange restrain may be the reasons that aggravate CO2 retention and respiratory acidosis in cor pulmonale patients with type II respiratory failure. (2) band 3 protein anion transport function impairment in patients of cor pulmonale with type II respiratory failure is reversible. Therefore, it was necessary to supply oxygen to cor pulmonale patients with hypoxemia in time, which may contribute to the recovery of anion transport function.
A gene library was constructed from large plasmid DNA of wild strain E519/66A of human enterotoxigenic Escherichia coli (ETEC). Positive colonies containing CS6 antigen were obtained. The CS6 gene fragment was identified by restriction endonuclease mapping. It was approximately 4.6 kb in length and responsible for encoding CS6 genes and regulating the CS6 antigen. Two forms of fimbriae protein with different molecular weight were produced by the selected clones. Both of them could react with the same CS6 antiserum. So we expect to use the recombinant strain as candidate for human ETEC vaccine development, and it is also useful for further research on the expression and regulation of genes encoding CS6 fimbriae protein.
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Human ovarian cancer cell line SKOV3 was grown during a period of four months in the presence of increasing concentrations of cisplatin (25-100 ng/ml). In the course of this treatment, the cells exhibited dramatic changes in morphology, including reduction in cell size, loss of cellular projections and clustering. This was accompanied by the appearance of P-glycoprotein (Pgp) on the cell membrane, as detected by flow cytometry and immunochemistry methods using the anti-Pgp monoclonal antibodies MRK16 and C219. The new cell line, designated SKOV3/CIS, was also resistant to alkylating agents, such as chlorambucil, similarly to the parental SKOV3 cells. In addition, it also acquired resistance to classical multidrug resistance drugs, such as doxorubicin, taxol and actinomycin D. Verapamil enhanced the sensitivity of SKOV3/CIS to doxorubicin (260-fold), in conformity with the proposed mechanism of Pgp in multidrug resistance (MDR), but it did not potentiate cisplatin cytotoxicity in SKOV3/CIS cells. Our results suggest that cisplatin can cause Pgp expression, and that both cisplatin-resistance and Pgp-mediated MDR phenotypes can coexist in some tumor types. Although Pgp does not appear to be responsible for cisplatin resistance, exposure to cisplatin can lead to the development of MDR phenotype, a complication that should be considered in clinical situations, especially in the chemotherapy of ovarian cancer.
Fresh tissue of human choriocarcinoma was injected subcutaneously into the BALB/C nude mouse. The xenografts had grown up with 16-68 passages. The hCG level of the ascites or intratumoral blood was 400-20,000 mIU/ml. Radioimmunodetection was performed using 131I labelled murine anti-hCG McAb. The labelled antibody could be specifically accumulated in the tumor sites and the tumor imaging was acquired. The ideal imaging time was 72-96 hours after the injection of antibody.
Percutaneous balloon mitral valvoplasty (PBMV) and radiofrequency catheter ablation (RFCA) have been used in the treatment of mitral stenosis (MS) and supraventricular tachycardia. The techniques of PBMV and RFCA yield better results with the development of interventional cardiology, but there is no report about PBMV performed simultaneously with RFCA in the same patient. Seven patients with mitral stenosis and Wollf-Parkinson-White (W-P-W) Syndrome were successfully treated with PBMV and RFCA by transseptal methods. LA, LAP, mPG and mPA were decreased from 43.4 +/- 4.6mm, 21.8 +/- 6.8mmHg, 21 +/- 7.7mmHg and 45.7 +/- 16.5mmHg to 39.2 +/- 3.7mm (P < 0.05), 12.7 +/- 4.5mmHg, 12 +/- 3.7mmHg and 32.3 +/- 9mmHg (P < 0.01). MVA was increased from 0.96 +/- 0.33cm2 to 1.7 +/- 0.80cm2 (P < 0.01). delta wave disappeared in 12-lead surface EKG and SVT could not be induced in electrophysiological study after the treatment. The overall time of the procedure for this series was 93 +/- 34 minutes and fluoroscopy time was 23 +/- 7 minutes on the average. Radiofrequency energy applications were 3 +/- 2 times each procedure. PBMV and RFCA are safe and highly effective in the treatment of MS and W-P-W syndrome. The results in the present study proved the feasibility of the combined use of PBMV and RFCA. We prefer a first choice of PBMV and then RFCA in order to avoid aggravation of the hemodynamics due to mitral stenosis. The results also showed that of overall procedure and fluoroscopy only took a short time for this series. We suggest that it could be used as a routine method for the treatment of mitral stenosis complicated by W-P-W syndrome.
The effects of Tetrandrine (Tet) on intraacinous pulmonary arteries (IAPA) and bemodynamics were studied by means of a rat pulmonary hypertension model induced by monocrotaline. The results showed that Tet could reduce the contractive pressure of pulmonary artery, right ventricle and right atrium of heart by 28.0%, 28.3%, and 31.5% respectively. It could also decrease the vascular degeneration of endoepithelial cells of IAPA, the endoepithelial subcavity, the collagens of medial membrane and the numbers of smooth muscles of IAPA.