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Biomedical subjects

W G Li

Publications and source records attributed to W G Li.

52 records · Page 3Linked to original sources
PubMed1992

[Dynamic changes in the platelet granule membrane glycoprotein level in patients with acute myocardial infarction].

Platelet granule membrane glycoprotein (GMP-140) level was measured by using 125I labelled monoclonal antibody (SZ-51) in 20 patients with acute myocardial infarction in the first three days and at the first three weekends. The correlation of severe arrhythmia and administration of aspirin with platelet GMP-140 in AMI were studied respectively. It is shown that platelet GMP-140 increased significantly in the first three days after AMI, then it dropped quickly, but remained at high level as compared with the controlled group till the third weekend (P < 0.01). Platelet GMP-140 level was higher in the first three days than at the first three weekends (P < 0.01). The changes of platelet GMP-140 have not been shown to be related with severe arrhythmia or administration of aspirin (P > 0.05). The results indicated that the platelets in AMI are activated continuously in the first three weeks after infarction; it might be thought as an important index of coronary artery thrombus formation.

Aged↗
PubMed1991

A preliminary report on the intervention trials of primary liver cancer in high-risk populations with nutritional supplementation of selenium in China.

The purpose of this study was to evaluate the effect of selenium (Se) in the prevention of human primary liver cancer. Three intervention trials were conducted among the residents at high risk to primary liver cancer (PLC) in Qidong county, Jiang-su province, the People's Republic of China. This area has the second highest rate of PLC in China. One trial was undertaken among the general population in a township with supplement of table salt fortified with 15 ppm anhydrous sodium selenite (Se-salt) for 5 y and the other four townships with similar PLC incidence rate served as the controls using normal table salt. The second trial was undertaken among hepatitis B virus surface antigen carriers (HBVsAg+) receiving supplement of 200 micrograms Se in form of selenized yeast (Se-yeast) daily vs placebo for 4 y. The third trial was carried out in members of families with high PLC incidence using Se-yeast (200 micrograms of Se daily) vs placebo for 2 y. The results showed that nutritional supplement of Se could reduce the PLC incidence significantly.

Adult↗
PubMed1991

Progesterone-dependent cathepsin L proteolytic activity in cat uterine flushings.

Sequence analysis of a cDNA clone for the progesterone-dependent protein (PDP) of the cat uterus revealed that PDP may be cathepsin L. This study was undertaken to directly measure the cathepsin L activity in uterine flushings from pregnant and ovariectomized steroid-treated animals in order to confirm that PDP is cathepsin L. Optimum activity toward the substrate Z-Phe-Arg-NMec was observed at a pH of 5-6. Z-Phe-Phe-CHN2, a specific inhibitor of cathepsin L, significantly inhibited the proteolytic activity present in uterine flushings. Immunoabsorption of PDP from uterine flushings obtained from progesterone (P)-treated cats reduced cathepsin L proteolytic activity to levels observed in ovariectomized and estradiol (E2)-treated animals. In E2-primed and E2 + P-treated animals, proteolytic activity in uterine flushings was detectable after 7 days and peaked after 11-13 days of E2 + P treatment. This proteolytic activity was also dramatically increased before implantation (10-12 days after coitus) in pregnant cats. Thus, our data indicate that changes in cathepsin L activity in uterine flushings are correlated with changes in PDP, the uterine protein synthesized and released from the epithelial cells of the deep uterine glands. PDP, via its cathepsin L proteolytic activity, may play a role in the implantation process.

Animals↗
PubMed1991

Insect resistance of transgenic tobacco plants expressing delta-endotoxin gene of Bacillus thuringiensis.

The initiative B.thuringiensis delta-endotoxin (Bt toxin) gene clones TH12 and TH48 contain two different classes of homologous genes, the 5.3 kb class and 6.6 kb class, respectively. Bt toxin genes of both classes, modified at the 5'-end and truncated at the 3'-end, can still be expressed to produce the insecticidal, truncated toxin proteins in E. coli. The modified Bt toxin genes were inserted into the plant binary expression vector pBin 437 (a derivative plasmid of pBin 19) and were transferred into tobacco by Ti plasmid-mediated gene transfer system. Southern blot and DNA slot blot analysis indicate that the Bt toxin genes have been integrated into tobacco genome at a copy number of 1 to 5. Northern blot analysis of polyA+ RNAs from progeny of the transgenic plants revealed that Bt toxin genes of both 5.3 kb and 6.6 kb classes were expressed in transgenic plants, though the transcripts were degraded to RNAs of lower molecular weights. In insecticidal test, 5 plants from the progeny of 5.3 kb class gene-transformed SR1 tobacco plants and 3 plants from those of 6.6 kb class gene-transformed plants were found to be toxic to the testing larvea of H.assulta. In comparison with the control, mortality of the insects fed on transgenic plants reached 40-50% and the growth of the survived insects was remarkably inhibited. These results indicate that the modified Bt genes of the 5.3 kb and 6.6 kb classes were expressed in transgenic plants and could confer on the transgenic plants a new character of insect resistance.

Animals↗
PubMed1990

Immunological detection of cat uterine proteins in ferrets, dogs and baboons.

In the cat, a high molecular weight (greater than 320 kDa) estrogen (E2)-dependent protein (CUPED) and a group of low molecular weight (28 kDa, 36 kDa, 41 kDa) progesterone (P)-dependent proteins (PDP) are synthesized by the epithelial cells of the deep uterine glands and secreted into the lumen. The present study was designed to investigate the possibility that other species synthesize proteins similar to CUPED and PDP in response to steroids. Uterine flushings and media from cultured endometrial explants obtained from E2 or P dominated animals were analyzed on Western blots for the presence of proteins which cross-react with antibodies raised against CUPED and PDP. CUPED antibody immunoreacted with a protein band at approximately the same molecular weight as CUPED in the media and flushings from E2-treated ferret, dog and baboon, but not from rat, mouse or hamster. In the cat, ferret and dog, specific immunocytochemical staining was observed in the apical portion of the secretory cells. In the baboon, staining was observed in both the basal and apical areas of the epithelial cells. The presence of CUPED in the uterine lumen during the E2-dominated phase of the reproductive cycle in several species suggests that CUPED may play a general role in providing the necessary biochemical milieu for reproductive success. The PDP antibody did not cross-react with proteins in the media of species other than cat, and therefore may be unique to the cat.

Animals↗
PubMed1989

Experimental study of free periosteal autograft. Animals age and periosteal osteogenesis.

This is a study of the correlation between the age of animals and the osteogenic potential of free periosteal autograft. The tibial periosteum of 27 rabbits, ranging in age from 4-104 weeks, was stripped and implanted into the quadriceps. Radiographic and histologic examination demonstrated that new bone was formed in both the young and adult rabbits. The morphologic basis and mechanism of bone formation of periosteum are discussed. Maintenance of integrity of the cambium layer of the periosteal graft is emphasized. Free periosteal graft of adult rabbits in the "resting" state can retain its osteogenic potential and produce new bone.

Aging↗
PubMed1989

Experimental study of free periosteal autograft. II. Increasing osteogenesis of periosteum.

The difference in osteogenesis of the periosteal graft and the effects of changing the recipient environment were studied in 26 young and 16 adult rabbits. The periosteal grafts from bilateral tibiae were implanted to the right and left sides of the abdominal wall, on the right side a coagulum was added. For quantitative examination, radionuclide, CT, ion-selective electrode, atomic absorption spectrometry and biochemical autoassay methods were used. The results showed that osteogenesis of periosteal grafts may increase by changing the local environments. The amount of periosteal bone formed in the adult rabbits was obviously less than in the young. The bone formation of the periosteal grafts with a coagulum, especially in the adults was increased. The possible mechanism of increasing periosteal osteogenesis by the coagulum is discussed.

Animals↗
PubMed1986

[Regional distribution of liver cancer and its relation to selenium levels in Qidong County, China].

The selenium (Se) level in barley and maize from 43 communes of Qidong county, a high risk area of liver cancer in China, were assayed. An inverse correlation between the Se level and the liver cancer incidence was observed. An inverse correlation was also observed between the blood Se level and liver cancer incidence of the local residents. When selenite solution was sprayed on the crops during their preflowering, the content of Se in barley and maize was increased by 6 fold over the control. It is suggested that the increase of blood Se level of the residents who live in the low-Se areas by this method be useful in the prevention of liver cancer.

China↗
PubMed1983

Relation between geographical distribution of liver cancer and climate-aflatoxin B1 in China.

This paper analyses, for the first time in China, the relationship between the data on climate (temperature and humidity) in the country, aflatoxin, hepatitis B and primary liver cancer mortality, by using the methods of geographical epidemiology and generalized factor analysis, and also approaches the characteristics of the geographical distribution of liver cancer in China from a climate-mould viewpoint. The authors come to the conclusion that climate is an important environmental condition that determines the differences in the distributions of liver cancer in different areas, and that aflatoxin B1 is one of the main carcinogenic factors of liver cancer.

Aflatoxin B1↗
PubMedDate not supplied

Chemoprevention trial of human hepatitis with selenium supplementation in China.

A three-year study has been conducted for prevention of infectious hepatitis with supplementation of table salt fortified with 15 ppm anhydrous sodium selenite to the general population of 20,847 persons in a township M.Z. at Qidong County, Jiangsu Province, China. The results showed that the incidence of virus hepatitis infection in the test township was significantly lower than that of controls provided with normal table salt. The incidence rate of infectious hepatitis in the treated township M.Z. was 1.20 and 4.52 per 1,000, whereas the average incidence in the 6 surrounding control townships was 2.96 and 10.48 per 1,000 in 1986 and 1987, respectively. The incidence of hepatitis B surface antigen (HBsAg+) was 13.2% vs 19.23% for males and 10.42% vs 12.24% for females in the supplemented vs nonsupplemented neighboring township, respectively. Epidemiological studies have demonstrated that a low grain Se content is associated with a high regional incidence of hepatitis B virus infections.

Adult↗
PubMedDate not supplied

Selenium chemoprevention of liver cancer in animals and possible human applications.

An inverse correlation between geographic distribution of liver cancer incidence and the selenium (Se) contents of whole blood and grains was observed in Qidong county, Jiangsu province, a high liver cancer area of the People's Republic of China. Animal experiments demonstrated that supplementation of Se reduced the incidence of liver cancer in rats exposed to aflatoxin B1. Se was also shown to inhibit the growth of transplanted tumors. A lower incidence of liver preneoplastic alterations and reduction of hepatitis B virus infection in ducks by Se-supplementation was observed, and three pilot studies for a Se-intervention trial on human liver cancer were carried out on the residents of Qidong county. A protective effect on the cellular DNA damage induced by aflatoxin B1 was observed in lympocytes from human with Se-supplements.

Aflatoxins↗