Biomedical subjects
Publications and source records attributed to G Song.
This paper is a preliminary report on the molluscicidal activity of seed of Camellia sinensis (L) O. Kuntze (SCS). Its LD50 and LD90 were 10 and 16 micrograms/ml, respectively. We found also SCS inhibited oxygen consumption 65% and glycogen content of Oncomelania snail by 80%. The activity of hatching eggs to juvenile snails was inhibited by this seed at 8-16 micrograms/ml. Juvenile snails may also be killed by this molluscicide.
A simple and sensitive technique to detect point mutation of the p53 gene using silver staining method for single-strand conformation polymorphism analysis of polymerase chain reaction (PCR-SSCP) is reported. In this study, the aberrations of the p53 gene (exon 6-8) in clinical specimens of primary cervical carcinoma were examined. Of 27 tumor tissues 2 samples showed mutations of p53 exon 7. Absence of abnormal bands in the p53 exon 6-8 in all ten normal cervical tissues. It appears that inactivation of p53 gene by point mutation is infrequent in clinical samples of human cervical carcinomas.
To identify the characteristics and extent of orbitocranial tumor for the selection of operative methods, 64 patients with the tumor were studied with clinical materials, primarily CT and magnetic resonance imaging (MRI) appearances. The lesions were found in the orbit, cranium and orbito-cranium boundary parts and their diagnoses in regard to localization and identification could be made. Based on the preoperative diagnosis of an orbito-cranial tumor, its location, character, secondary changes and operation(s) in the past, a surgical approach was designed. The resection of a tumor could be completed in once or in several times of operation. 64 operations were performed on 53 patients and other therapies were given to the other 11 patients. The operative methods included orbitotomy via anterior route, 21 times via lateral route and 30 times via transcranial route. The operative results suggest that the transcranial route be complicated and have more complications; preoperatively, the operative indication be strictly selected and intraoperatively, ophthalmologists closely cooperate with neurological surgeons.
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By digital subtraction angiography (DSA), the authors made observations on 108 normal ophthalmic arteries in 80 patients with regard to the origins, courses, branching, morphology and anastomoses of the vessels. The merits and demerits of DSA in observing the ophthalmic artery were discussed.
The recombinant plasmid PAS1-HPV16E6 containing the HPV16E6 gene was expressed in E. coli AR120 under nalidixic acid induction. A 19KD expression protein was isolated, purified and identified. Mice were immunized with the purified E6 expression protein. A murine hybridoma, RAC6, was obtained by fusing splenic cells from an immunized BABL/c mouse with mouse myeloma cell line SP2/0-Ag14 cells, followed by screening in HAT medium, cloning and recloning in methyl cellulose. The hybridoma RAC6 stably produces specific monoclonal antibody against the E6 expression protein.
We report the two-dimensional nuclear magnetic resonance (NMR) characterization of the stoichiometric complex formed between the snake venom-derived long alpha-neurotoxin, alpha-bungarotoxin (BGTX), and a synthetic dodecapeptide (alpha 185-196) corresponding to a functionally important region on the alpha-subunit of the nicotinic acetylcholine receptor (nAChR) obtained from Torpedo californica electric organ tissue. BGTX has been widely used as the classic nicotinic competitive antagonist for the skeletal muscle type of nAChR which is found in the avian, amphibian, and mammalian neuromuscular junction. The receptor dodecapeptide (alpha 185-196) binds BGTX with micromolar affinity and has been shown to represent the major determinant of BGTX binding to the isolated alpha-subunit. Previous studies involving covalent modification of the native nAChR from Torpedo membranes with a variety of affinity reagents indicate that several residues contained within the dodecapeptide sequence (namely, Tyr-190, Cys-192, and Cys-193) apparently contribute directly to the formation of the cholinergic ligand binding site. The NMR-derived solution structure of the BGTX/receptor peptide complex defines a relatively extended conformation for a major segment of the "bound" dodecapeptide. These structural studies also reveal a previously unpredicted receptor binding cleft within BGTX and suggest that BGTX undergoes a conformational change upon peptide binding. If, as we hypothesize, the identified intermolecular contacts in the BGTX/receptor peptide complex describe a portion of the contact zone between BGTX and native receptor, then the structural data would suggest that alpha-subunit residues 186-190 are on the extracellular surface of the receptor.
Experiments were done on 23 pentobarbital anesthetized adult cats. 67 units recorded from the parabrachial and Kölliker-Fuse nuclear complex (NPBM-KF) could be antidromically activated by electrical stimulation of nucleus raphe magnus (NRM). Of the 67 units, 7 were respiratory related units (6 inspiratory, 1 expiratory). These comprise 8% of the 87 respiratory units examined. The antidromic latencies ranged from 0.4 to 2.5 ms. After injection of WGA-HRP (wheat germ agglutinin-conjugated horseradish peroxidase) into the NRM, many retrogradely labelled neurons were observed in the NPBM-KF. These results showed that neurons in the NPBM-KF sent axonal projections to the NRM, which may be involved in the control of respiration as well as nociception.
An inactivated golden hamster kidney cell culture (GHKC) vaccine against haemorrhagic fever with renal syndrome (HFRS) has been developed in recent years. A monovalent GHKC vaccine (lot 88-17) was prepared with L99 strain of the rat-type hantavirus, adapted in suckling mouse brain, cultivated in GHKC, and inactivated with 0.025% formalin, and a preliminary trial of the vaccine was carried out in a small number of human volunteers with the approval of the Ministry of Public Health, PRC, in order to identify safety and antibody response of the vaccine. Three inoculations were made on days 0, 7 and 28 respectively, by the intramuscular route with 1 ml vaccine each time for every volunteer. No obvious side effect was observed in vaccinees within 3 days after each inoculation. All 12 vaccinees (10 received three inoculations, and two received two inoculations of the vaccine) showed positive seroconversion of IgG antibody (by IFAT and ELISA) and neutralizing antibody (by enzyme focus reduction neutralization test, EFRNT), and 10 of them were still seropositive 180 and 360 days after the first inoculation. These results suggest that this vaccine would be safe for human use, and could effectively induce IgG and neutralizing antibody responses.
OBJECTIVE: The aim was to determine the exact sequence of hormone changes during the progression of fluid retention in a canine model of "congestive cardiac failure" induced by rapid right ventricular pacing, and during recovery when pacing is stopped. METHODS: Rapid ventricular pacing at a rate of 250 pulses.min-1 was used in six mongrel dogs with implanted right ventricular pacemakers. Right heart haemodynamics were measured by means of Swan Ganz catheterisation, allowing flow measurement by thermodilution and pressure measurement by external manometry. Plasma renin activity, arginine vasopressin, and atrial natriuretic factor were assayed on venous blood samples by radioimmunoassay. Noradrenaline was assayed by high pressure liquid chromatography. RESULTS: The onset of rapid pacing was accompanied by a fall in cardiac output and a rise in pulmonary arterial, pulmonary capillary wedge, and right atrial pressures. Noradrenaline and atrial natriuretic factor rose. Plasma renin activity showed an initial fall followed by a rise, and arginine vasopressin was unchanged in the first 8 h. When rapid pacing was continued for a further 35 d, clinical signs of fluid retention appeared by day 28, by which time cardiac output had fallen, and central pressures risen further. Atrial natriuretic factor peaked at around 14 d whereas plasma renin activity, arginine vasopressin, and noradrenaline tended to reach a plateau at about d 20 and then to show further increases as clinical signs of fluid retention appeared; this was most marked with plasma renin activity. Cessation of pacing at d 35 caused a rapid reversal (increase) of cardiac output but a more gradual reversal (decrease) of right heart pressures over 5 d; only wedge pressure returned to base line. Arginine vasopressin and plasma renin activity fell rapidly to around 40% of the final pacing levels and reached basal values after 8 h and 48 h respectively. Noradrenaline fell after 8 h and reached basal levels in 5 d. Atrial natriuretic factor fell quickly by 60% after 8 h but remained above basal levels for 5 d. At the end of pacing, body weight fell rapidly in conjunction with a large diuresis. CONCLUSIONS: These findings are compatible with a major role of one or more of renin, vasopressin, and noradrenaline in the pathophysiology of the fluid retention of heart failure; the manifestations are not counteracted by the rise in atrial natriuretic factor.
To elucidate the importance of glucose metabolism in Oncomelania snails, uniformly labelled D (14C)-glucose [(U-14C)-glucose] has been used as a tracer for observing glucose uptake, incorporation into macromolecules and the activity of enzymes involved in its metabolic pathway. Radioactivity of Oncomelania increased with time of exposure (3, 6, 12 and 24 h) to [(U-14C)-glucose] solution. In snails treated with 2 ppm bromoacetamide for 24 h, the radioactivity of soft tissues was markedly less than that of normal snails. Oncomelania can synthesize glycogen from absorbed glucose, and the absorbed (U-14C)-glucose may be incorporated into nucleic acid, protein and lipid, with 14CO2 excreted as an end metabolic product. 6-phosphoglucose dehydrogenase and 6-phosphogluconate dehydrogenase activities were demonstrated by the reduction of NADP and determination of 14CO2 from (1-14C)-glucose, respectively. The results indicate that there exists a phosphopentose pathway in Oncomelania.
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A murine Hybridoma, CEB9, which stably produces monoclonal antibody against human uterine cervical carcinoma is described. CEB9 was obtained by fusing splenic cells from a BALB/c mouse immunized with human uterine cervical carcinoma cell line CC-801 cells with mouse myeloma cell line SP2/0 -Ag14 cells, followed by cloning and subcloning. The antibody is identified as IgG. The results of immunocytochemistry and fluorescence analysis show that the antibody reacted strongly with human uterine cervical carcinoma cells only among the following tested cell lines: PLC/RF/5, 7402, LETP-78, Scle, Hep-2, 2BS, as well as primary cultured human fibroblast cells. Pancreatic carcinoma cells were reactive.
Ten choroidal melanomas studied were with computed tomography (CT, nine cases) and magnetic resonance imaging (MRI, one case). Both techniques detected all the intraocular tumors with localization and determination of the extent of the lesions. Three of them were found to have extraocular extension. Because both T1 and T2 were relatively shortened in melanoma, on T-weighted MR image, the tumor was seen as an area of moderately high signal and on T weighted image, melanoma appeared as an area of low signal. MRI can provide a histological diagnosis of this tumor.
The activity of angiotensin converting enzyme(ACE) in crude extracts of the rat renal cortex was increased when the oxidizing agent diamide was added to the extract. The maximal activity was obtained at concentrations over 1 mM, and the value was twice or more the activity in the absence of the pretreatment. The activity of ACE was also increased by the diamide-pretreatment of the isolated membrane fraction of the renal cortex, thereby indicating that the increase in activity was not due to oxidation of endogenous glutathione (GSH) that may lower the ACE activity, but rather that ACE itself was oxidized. When O2 was included in the extract for 2 h, the ACE activity also increased to about twice the original activity. Lineweaver-Burk plots analysis demonstrated that, after oxidation with diamide and O2, the Vmax was increased but the Km remained unchanged. We conclude that the action of ACE in the kidney functions may differ in relation to oxidation of the tissue.
Three distinctive types of viral inclusion bodies were identified in hantavirus-infected cells by thin-section electron microscopy. The inclusion bodies, designated granular, granulofilamentous, and filamentous, were intracytoplasmic and closely associated with the rough endoplasmic reticulum and Golgi cisternae. Virus specificity of the inclusions was verified by immune colloidal gold and immunoperoxidase labeling. The inclusion bodies were a common morphological marker for 13 strains of hantaviruses studied, irrespective of their origin.
The role of renal angiotensin converting enzyme (ACE) in blood pressure regulation is not well understood. In our studies, both acute and chronic treatment of hypertensive rats SHR and SHRSP with ACE inhibitors Enalapril and SA446 had a blood pressure lowering effect that coincided with an inhibition of renal cortical and aortic ACE, but not plasma ACE. Further, ACE activities in the renal cortex and aorta were found to increase with aging of the SHRSP, therefore concomitantly with hypertension development. In the kidney, brush border membranes (BBM) contained abundant ACE. We found that the activities of ACE in the renal cortex closely correlated to the activities in isolated BBM, in Wistar Kyoto rats and in the SHRSP. Thus, renal cortical ACE activity and blood pressure correlated in cases of ACE inhibition and hypertension development. Since the ACE activity in the renal cortex appeared to reflect the enzyme activity in BBM, the brush border ACE may have to be taken into account, in view of the relationship between renal ACE and blood pressure.
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