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Biomedical subjects

W Li

Publications and source records attributed to W Li.

At least 901 records · Page 50Linked to original sources
PubMed1997

[Studies on cell senescence induced by D-galactose in cultured neurons and fibroblasts].

The cell senescence induced by D-galactose (D-gal) in cultured rat fetal brain neurons and human fetal lung fibroblast was investigated in vivo and in vitro. The results showed pronounced decreases in nerve cell diameters, number of process and percentage of multiprocess neurons including "pyramidal" and "stellate" shaped and a rather high level of mortality rate observed in D-gal-treated (8 g/L) neurons. Lessening of the proliferating population of lung fibroblast taken from rat treated with D-gal (50 mg/kg.d, subcutanous injection for 6 weeks) was observed. We have also determined the changes of cell cycle in human fetal lung fibroblast cells treated with D-gal (8 g/L): the proportion of the G0-G1 cells increased but the G2-M and DNA level and the results showed that decreased and the cell growth rate declined in comparison with those of the control. Lipid peroxidation was observed in both kinds of cells because D-gal was proved to have action of decreasing SOD activity and increasing MDA content, the results found in D-gal-treated rats were similar to those observed in hypoxanthine-xanthine oxidation reaction system (O2-), indicating that reactive oxygen was generated in the course of D-gal metabolism. It is concluded that D-gal has the hastening effect on cell senescence and oxidative stress might be responsible for this aging effect.

Aging↗
PubMed1997

[Effects of lithium chloride and harringtonine on the differentiation, proliferation and c-myc proto-oncogene expression of HL-60 cells].

This research was to observe the effects of lithium chloride (LiCl) and Harringtonine (HT) on the proliferation and differentiation of HL-60 leukemia cells. The results obtained by liquid suspension culture, semi-solid colony culture and 3H-TdR incorporation into HL-60 cells indicated that different concentrations of LiCl (5-20 mmol/L) and HT (10(-8)-10(-5)mol/L) exerted the inhibitory effects in a dose-dependent manner on HL-60 cell proliferation respectively. When LiCl (10 mmol/L) and HT (10(-7) mol/L) were added together in the liquid culture or semi-solid culture of HL-60 cells, they showed much greater inhibitory effect than that by each agent separately. It was discovered that there was induction of the differentiation of HL-60 cells by lithium and HT and the induction of HL-60 cells differentiation by HT was markedly enhanced by the addition of low concentration of lithium. This work also showed that by treating HL-60 cells with lithium and HT, the expression of the c-myc proto-oncogene was markedly decreased as measured by RT/PCR-mRNA (P < 0.01). These findings provide some evidence of the mechanismcausing leukemic change and of the potential use of lithium and HT in the treatment of leukemia and in vitro purging of leukemic cells for autologous bone marrow transplantation.

Antineoplastic Agents↗
PubMed1997

[The injury of Xenopus laevis oocytes membrane and its acetylcholine receptor by free radical and the protection of lycium barbarum polysaccharide].

The injury of the Xenopus laevis oocytes membrane and its acetylcholine receptor by free radicals was observed by exposing Xenopus laevis oocytes to the xanthine oxidase hypoxanthine (XO-HPX) reaction system. The results showed that under the action of free radicals the passive electrical membrane parameters changed significantly, this effect was directly proportional to the concentration of XO-HPX and the reaction time. The membrane function was not affected by 2 hours reaction with XO-HPX, while significant decrease of various membrane functional indices was found after more than 4 hours reaction, the Ach polarization decreased, the rise time prolonged, the degree of depolarization decreased, the decay 1/2 time shortened. SOD may be used to eliminate the effect of free radicals on the above mentioned membrane parameters. Lycium barbarum polysaccharide (LBP) may be used to improve the passive electrical membrane parameters of the injured membrane, but it does not lead to the recovery of Ach depolarization. The results suggest that the injury of cell membrane and Ach receptor by XO-HPX reaction system may be caused by the production of O2- free radicals. LBP may antagonize the action of free radicals on the membrane while it is ineffective in muscarine receptor injury.

Animals↗
PubMed1997

[The Chinese total diet study in 1992--macro elements and trace elements].

Ten macro elements and trace elements were directly determined in the 1992 total diet study conducted in four districts of China from north to south. The intake of these elements was evaluated. The levels of intake for seasonal variation and for different age groups were reported. The results showed that the intakes of Ca, P, K, Mg, Zn, Se and Cu were low in children. The intake of Ca, P and Zn was insufficient for adults. The intakes of other seven elements reached or approached their RDA levels, but there were big differences among the 4 districts. The relationships between intakes of Ca/P and Na/K as well as Fe and Cu and iron difficiency anemia were discussed.

Adolescent↗
PubMed1997

[Study on dietary pattern and nutrients intakes of residents in areas of high and low incidence of esophageal cancer].

The dietary pattern and nutrients intakes of residents in areas with high and low prevalence of esophageal cancer were studied by 3 days' dietary survey. The results showed that the dietary pattern and nutrients intakes of residents in areas with low prevalence (ALP) of esophageal cancer was superior to that in area with high prevalence (AHP). The amount of soybean, meat and vegetable consumed by residents in the ALP was more than that in the AHP. Deep color vegetable and gaelic vegetable were dominant in ALP, but so were light color vegetables in AHP. The protein quality and quantity as well as the amount of Zn, Ca, RE and riboflavin consumed in the AHP were lower than that in the ALP. The energy from carbohydrate accounts for 78.14% of the total in the AHP. It is suggested that poor dietary pattern and the quality and amount of nutrients intake may be related to the development of esophageal cancer, and nutrition intervention in area of high prevalence seems rational.

Adolescent↗
PubMed1997

[Molecular mechanism and therapy of hypoalbuminemia in peritoneal infection].

Albumin mRNA expression was studied by the use of reverse transcriptional polymerase chain reaction (RT-PCR) to determine the molecular mechanism in peritoneal infection. Albumin mRNA content markedly decreased. Endotoxin inhibited albumin mRNA expression in vivo probably by stimulating TNF,IL-1, and IL-6 production. Changes of the hormone levels were not the cause of hypoalbuminemia in infection. Reconbined growth hormone and astragalus polysaccharides alleviated inhibition albumin synthesis inhibition increasing albumin serum concentration in rats with peritoneal infection. The results suggested that hypoalbuminemia is associated with endotoxemia during sepsis, which inhibites hepatocytes albumin synthesis probably by stimulating nonparenchymal cells to produce TNF, IL-1, and IL-6.

Albumins↗
PubMed1997

[Influence of recombinant growth hormone on protein metabolism during severe infection: an animal experiment].

We observed the influence of recombinant growth hormone (rGH) on protein metabolism during sepsis and found its mechanisms. Cecal ligation and puncture were choosen to duplicate the severe infection model. Animals of therapy group received rGH 1 U/kg/d after CLP operation, while sepsis group received normal saline. rGH accelerated regaining of the positive nitrogen equilibrium, improved plasma albumin level. rGH accelerated the recovery of intestinal mucosa glutaminase activity, preserved the normal structure of intestinal mucosa, reduced the portal venous endotoxin level and venous TNF level. rGH improved the albumin synthesis of isolated hepatocytes, and inhibited the expression of albumin mRNA level during severe infection. We conelude that rGH preserves the normal structure and function of intestinal mucosa during sepsis, and reduces gut origin hypermetabolism reactions. Moreover, rGH improves the synthesis of protein.

Albumins↗
PubMed1997

[Primary renal epithelioid angiosarcoma with transitional cell carcinoma in renal pelvis].

To understand the clinical characteristics of primary renal epithelioid angiosarcoma. We used clinical pathology, immunohistochemistry and electron microscopy. Analysis and discussion about the case were combined with a review of the literature. We first report a female case of the left renal epithelioid angiosarcoma and concomitantly, transitional cell carcinoma developing from the renal pelvis at age 69. Epithelioid angiosarcoma showed positive results for FVIIIRA+, UEA, CD31, Cytokeratin and EMA. Weibel-Palade bodies were identified by electron microscopy. Primary renal epithelioid angiosarcoma was a rare clinical entity with a poor prognosis, which mimics epithelial tumor, both morphologically and immunohistochemically, and may be lead to misdiagnosis. The combined use of endothelial cell markers including FVIIIRA, CD31, UEA and electronmicroscopy can confirm the diagnosis of this neoplasm.

Aged↗
PubMed1997

[The application of corticosteroid following photorefractive keratectomy].

OBJECTIVE: The application methods of corticosteroid following excimer laser photorefractive keratectomy (PRK) were compared. METHODS: PRK was performed on 600 myopic eyes with Nidek-EC 5000 PRK System, and then randomly they were divided into group A (228 eyes) and B (372 eyes). Different methods of application of corticosteroid were performed in the two groups. The follow-up period was 6 months. RESULTS: After 6 months of follow-up, the rate of uncorrected visual acuity > or = 0.8 or > or = 1.0 was 97.9%, 93.2% in group A and 98.6%, 93.5% in group B, respectively. Transient ocular hypertension occurred in 2.2% in group A and 2.7% in group B, but the difference was statistically not significant (P > 0.05), the rate of haze greater than grade 1 was 18.4% in group A and 5.4% in group B, with statistically significant difference (P < 0.05). CONCLUSION: After PRK, the appropriate application of corticosteriod can effectively reduce the rate of haze formation and regression towards myopia caused by haze. Powerful corticosteroid used at postoperative early stage and its low concentration at later stage can reduce the incidence of corticosteroid ocular hypertension.

Administration, Topical↗
PubMed1997

[Macular light sensitivity and afferent pupillary function in children's amblyopia].

OBJECTIVE: To study the characteristics of macular light sensitivity (MLS) and relative afferent pupillary defect (RAPD) in anisometropic and ametropic amblyopia in school-aged children. METHODS: By using the static perimetry technique and swinging light test, we assessed MLS and RAPD in normal subjects, anisometropic and ametropic amblyopia in school-aged children. RESULTS: In comparison with the normal group, the MLS in both anisometropic and ametropic amblyopic eyes was significantly depressed. The MLS of the fellow eyes of the amblyopic eyes in anisometropic subjects was also depressed as compared with that of the normal group. The rate of RAPD was positive in 34.29% in the anisometropic amblyopic group. CONCLUSIONS: The static perimetry technique demonstrates a marked depression of MLS in all amblyopic eyes tested, suggesting a defect of visual X-channel. The pathogenesis of monocular amblyopia and binocular amblyopia is probably different, thus MLS examination can help assess prognosis. RAPD in anisometropic amblyopia may reflect a deficiency of peripheral visual system. The fellow eye of the anisometropic amblyopia eye may also be abnormal in terms of psychophysical standard.

Afferent Pathways↗
PubMed1997

[Kidney lesions complicated by hypoxic ischemic encephalopathy of neonatal pig].

To study the kidney lesions complicated by hypoxic ischemic encephalopathy (HIE) in newborn, we successfully established a neonatal pig model of HIE. Changes in brain tissue similar to those of newborn in HIE were detected after 2 hours of hypoxia and ischemia. Meanwhile, swelling of kidneys, hemorrhage below encapsules, swellin of tubular epithelial cells, necrosing and falling of a few tubular epithelial cells, and narrowing of tubular lumens were observed. The basement membranes of renal tubules remained normal serum BUN and creatinine increased significantly after experiment compared with before (P < 0.025 and P < 0.05 respectively). The results showed that the kidney of neonatal pig was damaged in HIE. But the injury was not severe. After 72 hours free from hypoxia, the structure and function recovered approximately from the injury.

Animals↗
PubMed1997

[Effect of tetrandrine on pulmonary vascular morphology in rats with hypoxia pulmonary hypertension].

To investigate the effect of Tetrandrine on pulmonary vascular morphology in rats with hypoxia pulmonary hypertension. We established the model of hypoxia pulmonary hypertension and observed the small pulmonary arterial morphologic changes under light microscope and electron microscope after the rats were treated with Tetrandrine; also, we made morphometric analysis. The results showed that the small pulmonary arteria in rats with hypoxia pulmonary hypertension was thinner than normal ones and had proliferation of smooth muscular cells. Morphometry displayed that the external diameter became smaller and that the ratio of vascular wall thickness to external diameter (M/T%) and the ratio of vascular wall area to total area (MA%) increased. The pathologic change significantly decreased after the rats were treated with Tetrandrine, indicating that Tetrandrine inhibited hypoxia-induced thickening and muscularization of small pulmonary arteria by inhibiting the proliferation of collagenous fibers so that narrowing of small pulmonary arteria was significantly slackened and pulmonary hypertension was alleviated. Therefore, we conclude that tetrandrine may partly prevent the development of pulmonary hypertension.

Alkaloids↗
PubMed1997

[The changes of glutamate receptor and free Ca2+i in hypoxic-ischemic cerebral injury: experimental study].

This experiment was designed to explore the pathogenesis in hypoxic-ischemic encephalopathy (HIE). Sixteen newborn pigs were divided into two groups: (Group A) normal control and (Group B) HIE 24 hours. The glutamate receptor (Glu R) in forebrain crude synaptic membrane (SPM) and free Ca2+i in RBC were tested respectively. The results revealed that the binding sites (Bmax) of Glu R in Group B was much lower than that in Group A, but the affinity (Kd) showed no statistic difference between Group A and Group B. In addition, free Ca2+i of RBC in Group B was much higher than that in Group A. This study demonstrates that the changes of Glu R and Ca2+i are involved in the pathogenesis of hypoxic-ischemic cerebral injury in newborn animals.

Animals↗
PubMed1997

[Effects of chronic hypoxia on calmodulin activity in rats].

To investigate the effects of chronic hypoxia of calmodulin activity in rats, we divided 40 wistar rats into four major groups. One group acted as control. The other three groups were made hypoxic by placing them in an isobaric hypoxic chamber (O2 = 10%) for 1, 2 and 3 weeks respectively. Calmodulin activity was measured by Phosphodiesterase method. The results showed that the mean pulmonary arterial pressure and the pulmonary vascular resistance in rats were remarkably increased by chronic hypoxia. The total calcium levels and the calmodulin content in the lung tissue of rats were significantly elevated at 2-3 weeks of hypoxia exposure. However, the calmodulin content in the lung tissue of the rats exposed to hypoxia for 1 week also increased, but it was lower than those at 2-3 weeks of hypoxia exposure. Therefore, we conclude that Ca(2+)-calmodulin system may play a central role in mediating hypoxai-induced pulmonary hypertension.

Animals↗
PubMed1997

[Uterine activity in active phase].

This study was designed to understand the uterine activity (UA) in normal labor. 43 nulliparous women(33 in normal course of labor and 10 in abnormal course of labor) were in the active phase of spontaneous labor with cephalic presentation for vaginal delivery. An open-end fluid filled intrauterine catheter connected to a pressure transducer was used to measure the uterine contraction intensity, frequency and duration. UA was quantified by means of Montevideo Unit (MU) and Uterine activity integral(UAI). The receiver operator characteristic(ROC) curve defined the cut-off points of UA between normal labor and abnormal labor. The results showed that MU and UAI were correlated with the rate of cervial dilatation in the active phase of labor (r = 0.3734 and 0.3502 respectively, P < 0.05). There was a strong correlation between MU and UAI (r = 0.7173, P < 0.001). The mean of UA in normal labor as MU = 226(s = 68.45) mmHg/15 min. UAI = 901(s = 258.02) kPa/15 min. The minimum of UA to normal labor in MU was 170 mmHg/15 min, of UAI 650 kPa/15 min. The study suggests that quantification of UA is very useful in the management of labor, especially in the proper use of oxytocin in cases abnormal labor.

Female↗