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Biomedical subjects

J F Li

Publications and source records attributed to J F Li.

34 records · Page 2Linked to original sources
PubMed1994

Seroepidemiologic study of Cryptosporidium infection in children from rural communities of Anhui, China and Fortaleza, Brazil.

A cluster-sampling, cross-sectional study was conducted for assessing the prevalence of Cryptosporidium infection in children less than 16 years of age from three villages, Dondian, Linshan, and Fuziyin, in rural Anhui in eastern China. Among 320 apparently healthy children less than 10 years of age from Dondian who had stool specimens collected, cryptosporidial oocysts were found in stools of three children from Dondian, and no positive specimens were found in 239 children studied from Linshan. In addition, a total of 610 serum samples from children in these three villages were tested for specific IgG antibody to Cryptosporidium with an enzyme-linked immunosorbent assay (ELISA) and the prevalence rates were 42.3%, 51.7%, and 57.5%, respectively, in Dondian, Linshan, and Fuziyin. Seroprevalence increased progressively with age. No detectable antibody was found in infants between two and six months of age, and seropositivity steadily increased after one year of age. Among 36 sera from adults 15-60 years of age without diarrheal illness in Huanglu villages of rural Chaohu, 50% (18 of 36) were positive. As expected, a good correlation was found in the specific IgG antibody between the paired serum specimens from 30 matched mother-neonates who showed transplacental transfer of IgG. However, little or no IgM antibody was seen in the neonates even though several mothers had a positive anticryptosporidial IgM enzyme-linked immunoassay result. Forty randomly selected serum samples from children less than four years of age in a similarly impoverished semiurban community in Fortaleza, Brazil, where the majority of households also have pit toilets and shared community water supplies and 172 serum samples from patients one month to 29 years of age admitted to the University of Virginia Hospital without diarrhea were also examined. In Fortaleza, almost all children acquired antibody by their second year of life, demonstrating the high prevalence of this infection. In rural Anhui, only about half the children were infected by 5-7 years of age. The overall prevalence rate (16.9%) of seropositivity among children and young adults in Virginia was much lower than in China and Brazil. These results indicate that cryptosporidial infection is ubiquitous, and is highly endemic in these impoverished communities. The difference between China and Brazil may reflect earlier weaning, hygiene practices, poorer water or sanitation, multiple siblings in family and geographic environment in Brazil.

Adolescent↗
PubMed1994

[An experimental study on photosensitization of cultured human cells with hypocrellin A].

The photosensitive effects of hypocrellin A on cultured HeLa cells were studied by the methods of immunofluorescence cytochemistry, flow cytometry and others. The results showed that, in the presence of 3.66 mumol/L hypocrellin A, illumination of HeLa cells with visible light, the morphology was changed and the microvilli on the cells were disappeared; the proliferation of the cells decreased with increasing irradiated dose and this effect seemed more sensitive in tumor cells than in normal cells; the increased population of cycle cells at S phase but decreased at G1 phase were observed by FCM; the photodamage effect of hypocrellin A induced the sparse distribution of cytoplasmic microtubles and almost disappearance of the fluorescence intensity of MTOC, they were observed in HeLa cells as shown by immunofluoresent microscopy. All the aforesaid results indicated that photosensitization of hypocrellin A inhibits cells growth, resulting from the damage in cell membrane and cytoskeleton and S phase delay of the cell cycle.

Cell Division↗
PubMed1994

[Synthesis of N-(4-carbomethoxy-4-phthalimidobutanoyl)-N-substituted glycines, proline and pyroglutamic acid].

This paper reports the synthesis of eleven N-(4-carbomethoxy-4-phthalimidobutanoyl)-N-substituted glycines (VII1-9), proline (VII10) and pyroglutamic acid (VII11) expected to have inhibitory activity on angiotensin converting enzyme. All of the compounds mentioned above and the corresponding t-butyl esters of VII1-9 were not reported in the literature previously. The structures were confirmed through their IR, 1HNMR, MS spectra and elemental analysis. In preliminary test in rats, compounds VII8, VII9 and VII10 showed marked hypotensive activity.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1993

Assessment of manure-application effects upon the runoff water quality by algal assays and chemical analyses.

The effects of manure-application mode, rate to soil, and rainfall characteristics on the quality of agricultural runoff water have been assessed by means of the algal-growth-potential test (AGPT) and chemical analyses. This study used two modes of manure application (i.e. surface mode and incorporation mode), three manure-application rates (0, 150, 300 kg N ha(-1)), and two rainfall intensities and times (i.e. 11 mm h(-1) for 142 min and 22 mm h(-1) for 71 min). The effects of the dilution of runoff water on algal growth were also examined. The algal yields obtained with runoff from soil with the incorporated manure mode are similar to those from soil without manure application and are lower than those with the surface mode of manure application. A higher manure-application rate increases the load of nutrients in the runoff and subsequently the algal yield. The dilution of runoff water can stimulate or limit the algal growth, depending on the concentration of toxicants, N (nitrogen) and P (phosphorus) from runoff and in the aquatic diluting medium. A lower rainfall intensity plus a longer rainfall time increases algal productivity. This study showed that N is the limiting factor to algal growth at low dilution but that, at high dilution or with the incorporation mode of manure application, P becomes the limiting factor to algal growth.

Journal Article↗
PubMed1993

Circulatory crisis caused by cigarette smoking in tissue transfer. Clinical and experimental studies.

Cigarette smoking-induced circulatory crisis occurred in two patients receiving toe transfer and one patient having musculocutaneous flap. After anticoagulation and antispasm treatment, one survived and two failed. Experimental studies demonstrated that cigarette smoking is harmful to the healing of endothelia at the anastomotic site of vessels. Five days after operation, the complete recovery rate of the endothelium over sutures of anastomotic sites was 16%-19% in smoking groups, but 75% in the control group. The mechanism and characteristics of circulatory crisis caused by cigarette smoking are discussed.

Adult↗
PubMed1993

[Effects of the jianpi yiqi prescription in treating infantile repetitive respiratory infection].

A clinical and experimental study to evaluate effects of the Jianpi Yiqi (JPYQ, Invigorate the spleen and supplement the Qi) prescription was conducted, in contrast to 51 cases treated with transfer factor. The results showed that there were statistically significant differences between two groups for therapeutical effects (P < 0.005). In the experimental group, the effective rate and the total effective rate were respectively 75% and 92.1; while in control group, 8% and 72%. Measuring immunoglobulin (IgG), both groups were increased, but the experimental group was higher than that of control (P < 0.001). The inactivation in oxygen free radicals of JPYQ was determined by electron spin resonance (ESR) in vitro. When the concentration was 5%, the clearance rate of the more reactive hydroxyl radical (.OH) was 78%, and superoxide radical (O2.-) was 38%. Whether direct dissolution or dissolution combined with dialysis was performed, there was superoxide dismutase (SOD) activity. In addition, the relationship between infantile repetitive respiratory infection with Spleen Qi Deficiency and free radicals were discussed.

Child↗
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↗