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Biomedical subjects

G Ren

Publications and source records attributed to G Ren.

32 records · Page 2Linked to original sources
PubMed1997

[Effects of cigarette smoke extract on proliferation and ET-1 release of airway smooth muscle cells].

OBJECTIVE: To investigate whether the effect of smoking on airway smooth muscle cells (ASMC) is mediated by the autocrine action of endothelin-1 (ET-1). METHODS: Abbit ASMC was cultured exposed to cigarette smoke extract (CSE), we examined the mitogenic effect CSE on ASMC in vitro and whether the ETA receptor antagonist JKC-301 can inhibit this effect. RESULTS: The exposure of ASMC to 10% and 30% CSE resulted in obvious cytotoxity. The viability of ASMC was decreased, the lipid peroxides (MDA) formation was increased, and the release of lactate dehydrogenase (LDH) into supernatant was enhanced. 5% CSE significantly enhanced the cultured ASMC[3H]-thymidine (3H-TdR) incorporation by 59.9% (P < 0.01) over control. The ASMC proliferative response to 5% CSE was dose-dependently inhibited by JKC-301. Moreover, 5% CSE evoked time-dependent release of endogenous ET-1 from ASMC. CONCLUSION: These data demonstrate that 5% CSE mediates ASMC proliferation via release and autocrine mitogenic action ET-1.

Administration, Inhalation↗
PubMed1997

Collecting duct carcinoma of the kidney.

OBJECTIVE: To describe the clinical, pathologic and immunohistochemical characteristics of collecting duct carcinoma (CDC) of the kidney. METHODS: Five cases of CDC (3 males and 2 females, aged 41 to 67 years) were identified between January, 1990 and December, 1994. Routine histopathologic study and immunohistochemical examinations of the surgical specimens were performed. RESULTS: Four patients underwent radical nephrectomy; 3 have been alive without evidence of recurrence for 3 months, 2 years and 2.5 years, respectively after the operation. Bone metastasis was noted 2 months after the operation in 1 case. One patient was submitted to simple nephrectomy because of extensive regional node involvement and died of lung metastasis 14 months after the surgery. Grossly, the tumors were usually grey-whitish in color and located in the renal medulla. Microscopically, the characteristic structure of tubulo-papillary pattern could be identified. Marked desmoplastic reaction was noted and atypical hyperplastic changes were found in the adjacent collecting ducts. Immunohistochemical studies revealed positive results to epithelial membrane antigen, high molecular weight cytokeratin and peanut agglutinin. CONCLUSION: CDC of the kidney is a rare disease with a poor prognosis. Radical nephrectomy is recommended even if the tumor is small.

Adult↗
PubMed1996

Approaches and reconstruction in skull base operation.

OBJECTIVE: To design convenient lateronasal and infrafrontal approaches or lateronasal subvolution approach to radically resect skull base tumors involving cranial cavity. METHODS: From 1987 through 1994, 22 patients with malignant tumors, 6 with benign tumors, one with a giant sphenoid sinus cyst and one with intranasal meningoencephalocele underwent the operation. Twenty-three cases had anterocranial fossa involved; 4, midcranial fossa; 2, anteromedial cranial fossa; and 1 case, posteromedial cranial fossa. Among the patients with malignant tumors, 11 underwent expansive maxillectomy and 10 had orbital contents resected. The intracranial approaches through lateronasal and infrafront (21 cases), nasal columella lateral subvolution (3 cases) and other approaches were used. RESULTS: The reconstruction of bony skull base defect in excess of 3.00 cm x 3.00 cm with total front musculocutaneous flap (8 cases), galeal and pericranial flap (5 cases) or other tissues (3 cases) has effectively prevented meningoencephalocele. Twelve cases had the dura resected in a range of 2.00 cm x 2.00 cm to 7.00 cm x 6.00 cm. Reconstruction of the dura defect with autofascia lata in 9 cases and other tissues in 3 cases effectively prevented the cerebrospinal fluid leak. Eight of 22 (36.4%) patients with malignant tumors have been alive and free of disease for 3-7 years after the operation. Six patients with benign tumors, one patient with giant sphenoid sinus cyst and one with meningoencephalocele were cured with this reconstructing method. CONCLUSIONS: Frontal musculocutaneous and pericranial flaps have advantages over free bone because of easy surviving and easy operating without occurrence of osteonecrosis and exclusive reaction.

Adolescent↗
PubMed1996

[Changes in urinary excretion of platelet activating factor and its significance in patients with primary nephrotic syndrome].

In order to explore the change of urinary excretion of platelet activating factor (PAF) and its significance in patients with primary nephrotic syndrome (PNS), we determined the urinary and plasma PAF in 12 cases of PNS, using platelet aggregation bioassay. The results showed that the level of urinary PAF was significantly higher in patients with PNS (n = 12) than in healthy controls (n = 10), but that of plasma PAF was comparable in patients with PNS and controls, suggesting that the excessive generation of PAF is confined to kidney. There was a significant positive correlation between urinary excretion of PAF and proteinuria (r = 0.73, P < 0.01). The results indicated that increased urinary excretion of PAF can serve as an indicator for augmentation of the permeability of glomerular basement membrane (GBM) in PNS.

Adult↗
PubMed1995

[Characters and insecticidal polypeptide of a new strain of Bacillus thuringiensis subsp. kenyae in China].

A new strain of Bacillus thurinigiensis Bt with high toxicity against noctuidae larvae has been screened for many generations since isolated from larvae candle of Aphomia gularis in Yiyang County, Jiangxi Province, in China. By comparison and analysis of results of physiological and biochemical test, flagella antigen identification and esterase type, the strain is identified as H4a-4c Bt serovar. kenyae. Since its crystal protein type and plasmid type are different from those of Bt serovar. kenyae's type 023. The strain is assigned a novel strain: Btken-Ag. Btken-Ag's parasporal crystals are multi-morphorous: bipyramid, cube, small irregular sphere and embedded. After UMT dissolve, PAGE and SDS-PAGE separation preparation and analysis, it is found that its major insecticide component to Heliothis armigera is 61kD toxic protein. By ELISA homology analysis, it is found that this toxic protein has high homology with crystal protein of 023 and 7501 (H4a-4c), partly homology with that of HD-1(H3a-3b), but no homology with that of Bti(H14) and (Bacillus sphaericus) Ts-1 strain. In bioassay with larvae from Culex pipiens, Pseudaletia unipuncta and Heliothis armigera, together with other ten Bt strains, Btken-Ag is toxic to 3 star larvae of Culex pipiens; two isolates of Btken-Ag (b1-4 and H4-1) show higher toxicity than type strain 023 and HD-1 do to Pseudaletia unipuncta and Heliothis armigera.

Animals↗
PubMed1995

[Pharmacological studies of Polygonum capitatum Buch-Ham. ex D. Don].

The pharmacological effect of aqueous extract of Polygonum capitatum has been studied. The experimental results show that Polygonum capitatum markedly decreases WBC and RBC in urine of pyelonephritis mode in rats, the death rate of Escherichia coli infected mice, and the temperature of feverish rabbits. It has also been found that after oral administration of Polygonum capitatum the animal urine markedly inhibits the growth of Escherichia coli, but diuretic action of the herb has not been observed.

Animals↗
PubMed1994

The effect of fibronectin on re-epithelialization of rabbits cornea after alkali burn.

The authors found experimentally that (1) fibronectin enhanced the healing of rabbit corneal epithelium after alkali burn and prevented the secondary breakdown; (2) it rapidly deposited on the denuded basement membrane to disappear as epithelial cells slid over, and (3) ultrastructurally, the neighbouring epithelial cells became flattened, with filopodia at the advancing edge, and extended to the wounded areas at 24 hours after the burn. However, the epithelial defects recurred 72 hours after the burn when the basement membrane vanished till after the 8th week, indicating that the latter was associated with the secondary epithelial breakdown.

Animals↗
PubMed1993

[Morphogenesis of Bacillus sphaericus Ts-1 and formation of toxic proteins to mosquito larva].

The close relationships between morphogenesis of Bacillus sphaericus Ts-1 and formation of toxic proteins were studied systemically and comparatively by Enzyme-Linked Immunosorbent Assay, FITC-IgG Location and SDS-PAGE etc. This study showed that the toxic proteins of Ts-1 were produced in 8h culture at 30 degrees C. The toxicity increased steadily along with the sporification and then declined as the free spores increased greatly without collection immediately. It is suggested that substances homologous with crystal toxic proteins were situated on the cell walls.

Animals↗
PubMed1991

[An experimental study on the selective ablation of AV node].

26 dogs were divided into two equal groups. Each dog was anesthetized, and a tetrapolar electrode was inserted transvenously to the area of AV junction. Unipolar leads of HBE were recorded with each of the four electrodes. The electrode where the highest H wave was recorded was considered to the contiguous to the His bundle, and the first or the second electrode proximal to the above-mentioned one was considered as in the vicinity of the AV node. These electrodes were used as cathodes, and electric discharges were performed with an external defibrillator. Two dogs in each group died of VF during discharge. Complete AV blocks were produced in all the other dogs. After discharge, in each of the 11 dogs in His bundle ablation group, the H wave disappeared, the escaping rhythm was slower and irregular, the QRS interval was wide, multiple ventricular extrasystoles or VT occurred, and 4 dogs died due to cardiac arrest within 3 days. These manifestations denoted that the block was situated in the His bundle, and the escaping rhythm focus located within the bundle branch or the ventricle. In contrast, the H waves still existed in 9 dogs of the AV node ablation group, the A waves dissociated with the H waves, the relationship between H waves and V waves was fixed, and H-V intervals were the same as before discharge. In all the 11 dogs, the morphology and the width of QRS did not change in comparison with those before discharge, the escaping rhythm was quicker and regular, and the incidence of ventricular extrasystole was low.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Separation and purification of the toxic protein of Bacillus sphaericus Ts-1].

Bacillus sphaericus strain Ts-1 is highly insecticidal to larvae of the mosquito. It's insecticidal component is toxic proteins. The toxin was extracted from spore-crystal complexes by disruption in a Sonicator Cell Disruptor Model W-220F followed by treatment with 0.05 mol/L NaOH. Fraction recovered from chromatography of the spore-crystal complexes on column of Sephadex G-200 were assayed against mosquito larvae and the toxic fractions from gel chromatography were subjected to SDS-PAGE. The toxic proteins in B. sphaericus Ts-1 spore-crystal complex migrated in position corresponding to 42kD and 43kD. Bioassay of the two purified proteins prepared by PAGE indicated that they were all toxic to mosquito larvae. Toxic protein was further purified by DEAE-cellulose chromatography. The toxic protein with a molecular weight of 42kD was obtained.

Animals↗
PubMed1990

[Enzyme-linked immunosorbent assay of larvicidal toxic proteins of Bacillus sphaericus Ts-1].

Bacillus sphaericus Ts-1 Mosquito larvicidal toxins 42 k Da and 43 k Da were isolated by Sephadex G-200 chromatography. Three strains of highly toxic B. sphaericus and two non toxic strains were screened for toxic proteins using ELISA. The lowest detectable toxin level was 1.56 X 10(-5) mg/ml. Non toxic strains did not produce antigens reacting to either the 42 kDa or the 43 kDa antibodies. Ts-1 cultures were examined at 12 and 24 h by LC50 bioassay against Culex pipiens. The LC50's at 12 h and 24 h were 0.71 ppm and 0.154 ppm, respectively, i.e., the toxin level at 24 h was 4.6 times the level at 12 h. ELISA tests established total toxin at 0.049 mg/ml and 0.225 mg/ml at 12 h and 24 h, respectively, confirming the LC50 study.

Bacillus↗
PubMed1990

[Processing technique of American ginseng].

The article deals with a new technique for processing American ginseng cultivated in China by far-infrared and moisture absorption. The qualities of processed product as per ton-quantity (including appearance, physical properties and chemical compositions) show no difference from those of American ginseng imported from U.S.A. and Canada. The mathematical model of dry-loss weight of American ginseng during processing is given in this article.

Amino Acids↗
PubMedDate not supplied

mRNA expression of proto-oncogenes and platelet-derived growth factor in proliferative vitreoretinal diseases.

PURPOSE: To detect the expression of mRNA of protooncogenes ets-1, c-jun, c-fos, and platelet-derived growth factor (PDGF) in proliferative membranes of patients with proliferative diabetic retinopathy (PDR) and proliferative vitreoretinopathy (PVR). METHODS: cDNA was synthesized from mRNA of proliferative membranes from patients with PDR, PVR, premacular fibrosis (PMF), acute retinal necrosis (ARN), and age-related macular degeneration (ARMD). Ets-1, c-jun, c-fos, PDGF-A, and PDGF-B cDNA were amplified using reverse transcriptase-polymerase chain reaction (PCR). RESULTS: Proto-oncogene mRNA was highly expressed in membranes from patients with severe PDR, grade D PVR. PDGF mRNA was expressed in almost all samples. CONCLUSIONS: Our results suggest that not only PDGF mRNA was expressed in the membranes of patients with PDR and PVR, but proto-oncogenes ets-1, c-jun, and c-fos mRNA were also expressed.

DNA Probes↗