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Biomedical subjects

J F Li

Publications and source records attributed to J F Li.

10 recordsLinked to original sources
PubMed1992

[Role of endothelium-derived relaxing factor in the contractions of intrapulmonary artery induced by oxygen-derived free radicals in chronic hypoxic rat].

The role of endothelium-derived relaxing factor (EDRF) on the effect of oxygen-derived free radicals (generated by xanthine-xanthine oxidase system) on intrapulmonary arterial in chronic hypoxic rats was studied by a microbioassay method. Intrapulmonary artery rings with intact or denuded endothelium of hypoxic (5,000 m, 10 days) and normoxic rats were prepared for observation of oxygen-derived free radicals induced contraction. It was shown that oxygen-derived free radicals induced contractions of intrapulmonary arterial rings with intact endothelium were obviously augmented in hypoxic rats than in normoxic controls. The augmented responses could be further potentiated by the addition of EDRF inactivator reduced hemoglobin (RHb), but diminished or even abolished by applying superoxide dismutase (Cu-Zn SOD). However, no effect on denuded rings was observed when RHb or SOD was added. It is concluded that chronic hypoxia may attenuate the action of EDRF in the enhancement of the reactivity of intrapulmonary artery to oxygen-derived free radicals.

Animals↗
PubMed1990

Determination of trace selenium in human body by anodic stripping voltammetry at gold-disc electrode.

For determination of trace Se we used high-pressure wet digester to pretreat the specimens obtained from the human body. This method is very effective in preventing loss of Se by volatilization which often occurs in the sample pretreatment. We studied the method of using anodic stripping voltammetry at gold-disc electrode to measure the trace Se present in the human body and found it to be the optimal procedure. The detection limitation was about 2 x 10(-8) g/L, the recovery rate of Se about 96.6 +/- 6.7% (chi +/- s), and the coefficient of variation CV = 7.0%.

Amniotic Fluid↗
PubMed1989

Scanning electron microscopic observations on the endothelial healing mechanism of vessels.

Systematic scanning electron microscopic observations of the healing mechanism in the endothelium of rat carotid arteries were carried out at the site of anastomosis. The site of needle holes and stitches are the main locations for thrombocyte adhesion and aggregation in normal vascular anastomosis. The repair process in endothelial injury can be divided into three stages. A thrombocyte-adhesion and filling stage is apparent at 1 hr postoperatively; this is also the period when thrombus is most likely to occur. A fibrin-covering stage is apparent at 2 hr after operation and reaches its peak in 24 hr. The formation of fibrin provides a framework for endothelial growth. In this period, there is still the possibility of thrombus formation. At 48 hr postoperatively, endothelial growth can be seen at the site of some needle holes. At 72 hr after operation, 47 percent of needle holes have endothelial growth, and the possibility of thrombus formation at the anastomotic site declines. The data suggest that eversion of the intima in vascular anastomosis and minimization of endothelial injury by considering the size of the needle hole, the duration of ischemia time, and perfection of surgical technique, are keys to the prevention of thrombus formation at the anastomotic site.

Anastomosis, Surgical↗
PubMed1986

[Mass photofluorography in early detection of peripheral lung cancer].

During 5 consecutive years of 100 mm photofluorography, 21 cases of primary lung cancer were discovered among 211,881 checked subjects in 54 factories in the suburbs of Beijing. Detection rate was 9.9/100,000. In the male smokers 40 years old or over, who comprised 13.7% of all examined with a detection rate of 55.0/100,000. Among the 21 cases, peripheral cancer was 61.9%, in which 38.4% were stage I 69.2% were treated by surgical resection, much higher than that of the central type. It may be concluded that photofluorography in mass screening has a certain value in early detection of the peripheral lung cancer and the male smokers 40 years or over should be examined as a priority group.

Adult↗
PubMed1983

Retina of river dolphin Lipotes Vexillifer.

The structure of retina of the Lipotes Vexillifer has been studied quantitatively under light microscope. The results obtained are as follows. (i) The thickness of the retina is 268 micrometer. The lamination of retina can be clearly distinguished. It consists of 10 layers. The thicknesses of the layers from pigment epithelium to internal limiting membrane are 12 micrometer, 44 micrometer, 2 micrometer, 48 micrometer, 20 micrometer, 36 micrometer, 68 micrometer, 32 micrometer, 8 micrometer and 2 micrometer respectively. (ii) The number of cells in the outer nuclear layer is larger than that in the inner nuclear layer. Two types of cell can be distinguished in this layer. The number of receptors and ganglion cells is in a ratio of 12 to 1. These results show that the retina type of the Lipotes corresponds to that of nocturnal animals. (iii) The diameters of ganglion cells range 1.5-37 micrometer with two peaks at 6 micrometer and 35 micrometer. This means that the ganglion cells fall into two groups according to size, and this has been proved by the observation on morphology of ganglion cells in the whole-mount preparation and sections of the retina. The percentages of large cells and small cells are 3% and 97% respectively. The proportion of small cells to large cells does not change greatly in different parts of the retina. (iv) No fovea and visual streak have been found in the retina.

Animals↗