Biomedical subjects

H Shu

Publications and source records attributed to H Shu.

At least 55 records · Page 3Linked to original sources

PubMed1995

[Research on the factors influencing the sporogonic multiplication of Plasmodium vivax in the mosquito vector].

Volunteers with no previous malaria history infected with northern Guangdong isolate of Plasmodium vivax and mosquito vector, Anopheles stephensi, were the objects and materials used in the research. Totally there were 16 volunteers, half of them were infected by mosquito-bite and another half by blood-inoculation. Blood was drawn when parasitemia reached a certain level and the erythrocytic forms developed into large trophozoites. Mosquitoes fed on infected blood from 5 and 4 donors of the two groups gave high gland infection rate and high gland indices respectively, but the highest gland indices were got from volunteers infected by mosquito-bite. The time of blood-feeding is important, only those blood samples taken from the people 3 to 8 days after the first onset gave good sporozoite harvest and the gland infection was greatly reduced on the 9th day. During this period (d3-8), the density of gametocyte had obvious influence on the intensity of mosquito infection. When the sex ratio of gametocyte (female:male) was 4:1 or less, the result would be good. For the purpose of reflecting more perfectly the circumstance of the sporogonic multiplication of plasmodium in the mosquito vector, we suggest the concept of gut/gland infection intensity which equals the product of the infection rate and the index of oocyst/positive gland.

Adult↗

PubMed1995

[Effect of environmental temperature, cryopreservation and aging on Plasmodium vivax sporozoites developing into exoerythrocytic stages].

After Anopheles stephensi mosquitoes with salivary infection of Plasmodium vivax were put in environments with temperatures of 30 +/- 1 degrees C, 26 +/- 1 degrees C or 13 +/- 1 degrees C for 5 d, their glands were aseptically dissected and sporozoites were collected and inoculated into HepG2-A16 cell monolayers. Seven days post-inoculation the cultured materials were harvested and the exoerythrocytic schizonts and hypnozoites were observed under the microscope by using immunoperoxidase staining technique. The results showed that the sporozoite developing rate of 30 +/- 1 degrees C group and 13 +/- 1 degrees C group was significantly lower than that of 26 +/- 1 degrees C group (0.33%, 0.35% and 0.75% respectively). The proportion of hypnozoites in the total number of EE forms was the highest in the low temperature group (62.5%) compared with 26 +/- 1 degrees C and 30 +/- 1 degrees C group (40.1% and 42.7% respectively). Suggesting that the low environmental temperature first affected the viability of tachysporozoites or the phenotype of sporozoites and thus resulted in heightened hypnozoite rate. This is parallel to the epidemiological data that in the regions of high latitute vivax malaria with long incubation period was more frequently observed. When the sporozoites within the body of mosquito were cryopreserved at -70 degrees C or in liquid nitrogen for 24 h or 5 d respectively, the proportion of hypnozoite increased 87.4% and 82.4%, respectively. However, cryopreservation did not inactivate all of the tachysporozoites, indicating that the resistance to ultralow temperature in bradysporozoite was much greater than that in tachysporozoites. Aging of sporozoites decreased their developing rate and the exoerythrocytic (EE) schizonts were found to grow sluggishly and asynchronously, indicating that the size of EE schizont and the age of sporozoites are in negative correlation. Meantime, proportion of the hyponozoite decreased significantly.

Aging↗

PubMed1995

[Observation on hypnozoite of different isolates of Plasmodium vivax in cultured materials].

The hypnozoites of different isolates of P. vivax from Shenzhen and Shixin, Guangdong Province, Changsha, Hunan Province and Yincheng, Hubei Province of China in cultured materials were observed employing immunoperoxidase staining method. The percentages of hypnozoites among exoerythrocytic stages were 40.1, 43.5, 50.6 and 57.1%, respectively, indicating that the percentage of hypnozoites and the latitude are in positive correlation. The equation is y = -6.68 + 2.05x. When the difference in latitude of Plasmodium vivax isolate source was more than 5 degrees, a significant difference in the percentage of hypnozoites in various geographic isolates was found. However, the average diameters of hypnozoites and schizonts among various geographic isolates showed no significant difference. The results showed that in the regions north to the Yangtze River, the proportion of hypnozoite in the liver stage of P. vivax was larger than those in the southern China, being consistent with the clinical manifestations.

Animals↗

PubMed1995

[A comparative study of fat emulsions clearance test using long chain triglycerides and medium chain triglycerides in volunteers].

Intravenous fat emulsions clearance test using long chain triglycerides (LCT) and medium chain triglycerides (50% MCT/LCT) were studied in ten healthy chinese volunteers. In the morning (8:00 AM) the lipid was infused continuously for 5 hours at rate of 0.17g.kg-1/h. There was an interval of two weeks between LCT and MCT/LCT. The peak concentration of serum triglyceride was smaller in MCT group. The area under concentration curve had significant difference between LCT and MCT groups (6108 +/- 461 vs 4495 +/- 362, P < 0.05). The serum free fatty acid was 628 +/- 42 in LCT and 1049 +/- 1 in MCT respectively in 5 hour (P < 0.001). The concentrations of very low-density lipoprotein (VLDL) in serum were increased in volunteers receiving LCT and MCT, but those of LDL and HDL were decreased. The blood sugar and cholesterol had no significant difference after lipids infusions. The study demonstrated that medium chain triglycerides was faster to be cleared than long chain triglycerides.

Adult↗

PubMed1995

Effect of monoclonal antibodies on the entry and development of Plasmodium vivax sporozoite in cultured cells.

We have observed the effect of monoclonal antibodies against sporozoites (2F2,NV3,2E10) and blood stages (4B2,8E3) of P. vivax on entry and subsequent development of P. vivax sporozoites in HepG2--A16 cells in vitro. The results demonstrated that inhibitory effects of monoclonal antibodies on the attachment and entry were found to be related to the antibody concentration. At 25 micrograms/ml, the percentages of inhibition of sporozoite invasion were 100% (2F2), 76%(NVS3) and 10.5% (2E10). Even if the invasion was not totally inhibited, the presence of abnormal exoerythrocytic schizonts suggested that continued effect of antibodies after sporozoite penetration still existed. No significant effects of 4B2 (4.5%) and 8E3 (3.4%) were recorded as compared with normal mouse serum. These findings indicate that inhibition of sporozoite invasion assay may be useful for determining the protective effect of anti-sporozoite antibodies in vitro.

Animals↗

PubMed1994

Muscarinic M1 receptor mediated inhibition of GABA release from rat cerebral cortex.

Presynaptic modulation of [3H]GABA release was examined using rat cerebral cortical slices. In vitro addition of carbachol, a muscarinic receptor agonist, resulted in a significant suppression of the release of [3H]GABA evoked by high potassium (50 mM) stimulation in a dose dependent manner, while noradrenaline, isoproterenol, dopamine, 5-hydroxytryptamine, histamine and glutamic acid had no significant effect on the evoked release of [3H]GABA. This suppressive effect of carbachol was antagonized invariably by atropine. Furthermore, it was found that the suppressive action of carbachol could be antagonized by pirenzepine, a selective M1 muscarinic receptor antagonist, but not by AF-DX 116 and 4-DAMP, M2 and M3 receptor antagonists, respectively. These results suggest that the release of GABA from cerebral cortical GABA neurons may be modulated by presynaptic M1 muscarinic receptor.

Animals↗

PubMed1994

[Seroepidemiologic study on the feasibility of screening for the antibody to HCV by pooling the serum specimens].

The feasibility of screening for the antibody to HCV by pooling 10 serum specimens was studied by utilizing the epidemiologic method of single blind random allocation. We changed only the ratio between the pooled serum specimen volume and the serum specimen diluent volume, with their total volume and single serum specimen volume being as much as the volume required by EIA. Other steps were the same as those of EIA. The result showed that taking single serum specimen as the control group, the sensitivity and specificity of pooled serum specimen were 100% and 97.6%, respectively. The false positive rate was 2.4%, Kappa value was 0.95 (P < 0.05). The analysis of profit found that remarkable social and economic benefit will be obtained when serum pooling method is used. These results demonstrate that pooling 10 serum specimens is feasible to screening the antibody to HCV in blood donors by EIA.

Adolescent↗

PubMed1994

[Simultaneous determination of serum copper and zinc levels in patients with cancer of the digestive tract by ion-exchange chromatography].

Serum copper and zinc were simultaneously determined by ion-exchange chromatography (IC) in 35 normal volunteers and 45 patients with benign diseases or different stage cancers of the digestive tract. No significant differences of serum Cu, Zn and Cu/Zn ratio were found among normal volunteers, patients with benign diseases and those with stage I or II cancers, while in the group of stage III and IV cancer patients, serum Cu (26.53 +/- 1.41 mumol/L) and Cu/Zn ratio (2.25 +/- 0.16) were very significantly elevated (P < 0.01) and that of serum Zn (11.78 +/- 0.46 mumol/L) was remarkably decreased (P < 0.05). Our results showed that serum Cu, Zn and Cu/Zn ratio were of no help in detecting early stage cancers and in differentiating them from benign diseases but were useful in predicting stages of cancers before operation for a better choice of therapy.

Adult↗

PubMed1994

[In vitro cultivation of the exoerythrocytic stage of Plasmodium vivax (southern China isolate)].

An in vitro culture system for the exoerythrocytic (EE) stage of Plasmodium vivax was first developed in our laboratory in China. Anopheles stephensi mosquitoes were infected by membrane feeding with heparinized blood from a volunteer. After 14-18 days, the mosquito salivary glands were aseptically dissected in culture medium and ground in a tissue grinder to form sporozoite suspension. Sporozoites were counted and added to the cultures of monolayer hepatoma cells at the number of 4.9 x 10(4)-1.3 x 10(5) per cover glass. Sometimes, 8-10 pairs of infected gland were added directly to the cultured cells. On day 7, EE schizonts of P. vivax were found in cultures. In addition, normal erythrocytes (type o) were added to the cultures on day 10 at a concentration of 10(8) per dish. Fourteen days later, erythrocytes in culture supernatant were collected and thin blood films were made. Numerous intra-erythrocytic P. vivax parasites were identified on the films after Giemsa staining. Most intra-erythrocytic forms were rings and early large trophozoites. Schuffer's dots were present in many of the infected cells which were pale and obviously enlarged. These results indicated that the in vitro hepatic cycle of P. vivax was established.

Animals↗

PubMed1993

A noninvasive video-based method for measuring lens transmission properties of the human eye.

The Lens Absorption Monitor (LAM) is an automated video-based system for obtaining rapid objective noninvasive measurements of the spectral transmission properties of the human lens. The technique is based on intensity measurements of the 4th Purkinje image for different wavelengths, and incorporates several features that overcome some of the difficulties associated with previous studies using this approach. LAM transmission measures for the visible spectrum can be obtained in approximately 2 s, and in most instances can be obtained without having to dilate the subject's eye. This paper describes the technique and presents our initial findings for 40 normal observers between the ages of 24 and 77 years. Results of the LAM technique show that it is able to measure the wavelength-dependent properties of the lens accurately and to identify age-related changes in "yellowing" of the lens. Test-retest reliability of the LAM is better than for psychophysical estimates of ocular media transmission. LAM and psychophysical measures in the same subjects were found to be correlated, although LAM measures produced consistently lower values of lens density than the psychophysical determinations. There was only moderate agreement between LAM and psychophysical measures of lens density. Possible explanations for these differences are discussed. Future research will determine whether this technique is able to detect and quantify early cataract development.

Adult↗

PubMed1993

Pharmacokinetics of a micronized, poorly water-soluble drug, HO-221, in experimental animals.

N-[[[4-(5-Bromo-2-pyrimidinyloxy)-3-chlorophenyl]amino]carbonyl] - 2-nitrobenzamide (HO-221) is presently under development as an oral anticancer agent with a novel mode of action. However, HO-221 exhibits extremely poor bioavailability after oral administration because it is only slightly soluble in water (0.055 micrograms/ml at 37 degrees C). Our previous study revealed that the micronization of HO-221 to the submicron region improved this oral bioavailability. In this study, the oral pharmacokinetics of this micronized HO-221 was investigated in rats, dogs and monkeys. After oral administration, the agent was moderately absorbed with the Tmax of 6.5-8.0, 17.3-20.0 and 12.0 h, and eliminated with the terminal half-lives of 11.9-15.0, 66.8-78.3 and 42.3 h in rats, dogs and monkeys, respectively. The bioavailability was incomplete (3.7-21.4%). In rats, the plasma concentration did not increase proportionally with increasing oral doses. In dogs, food enhanced the bioavailability 2.2-fold with a standard meal and 3.6-fold with a high fatty meal as compared with fasting conditions.

Administration, Oral↗

PubMed1993

[Study on subclinical infection with M. leprae--a follow-up].

In this article, we reported the results of studies on the rates of subclinical infection (SI) among leprosy contacts and a follow-up using PGL-I-ELISA. The results indicated that: (1) the rates of SI were higher in household contacts than those in around population; (2) factors such as type of leprosy, degree of contact affected the development of SI; (3) among 97 followed-up contacts, one person developed clinical leprosy in the second year; (4) acid-fast bacilli (AFB) were seen in the skin or peripheral blood of some subjects, some factors affecting SI, and the significance of AFB in skin and blood are discussed in detail.

Adolescent↗

PubMed1990

Structure and function of P-glycoprotein in the normal liver and intestine.

Multidrug resistance (MDR) genes encode a family of membrane glycoproteins of approximately 170 kD (P-glycoproteins). In man and mouse, the MDR 1 (mdr 1) genes confer resistance to relatively hydrophobic cationic anti-cancer drugs (i.e., vinblastin, adriamycin). Anti-cancer drug sensitivity is restored by addition of other drugs (i.e., verapamil, reserpine) which are also P-glycoprotein substrates. Transfection of MDR 1 genes produces the resistance phenotype and overexpression of P-glycoprotein. Parenchymal cells in several normal tissues express P-glycoprotein in the secretory domain of the plasma membrane (i.e., bile canaliculus of hepatocytes, brush border of proximal tubular, and small intestinal cells). Studies using plasma membrane vesicles of different sidedness derived from the bile canaliculus and small intestinal brush border permit characterization of P-glycoprotein as a unidirectional, temperature dependent, saturable, ATP-dependent transporter which is competitively inhibited by various anti-cancer drugs and other compounds. Transport studies using single cell fluorescence microscopy with image analysis confirm observations in vesicles. No natural substrate has been identified. Structural studies indicate that the requirements for substrates are molecular weight of 350 to 100, hydrophobicity, two planar rings, and a weak cationic charge. Alternative mechanisms of transport function are considered. The identity of P-glycoproteins in normal rat and human tissues has not been established. Antibody reactions suggest that they may belong to the MDR 2 or 3 class. Studies using everted gut sacs suggest that inhibition of P-glycoprotein may facilitate accumulation of anti-cancer drugs in the tissue.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1990

[A study of gene therapy for beta-thalassemia. I. Retroviral-mediated transfer of human beta-globin gene into Friend cells].

We used a replication-defective retrovirus vector containing the human beta-globin gene to transfect the ecotropic packaging cell line psi-2, and then harvested the virus supernatant to infect the amphotropic packaging cell line PA317. As a result, a recombinant vector producing cell line (PIW beta) with a titer of 1.1 x 10(5) CFU/ml was isolated. By infecting Friend cells with this high titer virus vector, high efficiency gene transfer was achieved. Southern blot hybridization analysis indicated that the intact human beta-globin gene was stably integrated into the genome of the target cells. Our results provide a useful reference for further studies of gene therapy of beta-thalassemia.

Blotting, Southern↗

PubMed1990

[Treatment and prevention of asymmetrical intrauterine growth retardation with huoxue huayu prescription].

The purpose of this study was to observe the therapeutical and preventive effect of the compound prescriptions of Huoxue Huayu (promoting blood circulation to remove stasis, PBCRS) and Yiqi Huoxue, replenishing Qi to remove stasis, RQRS) on experimental intrauterine growth retardation (IUGR) caused by passive smoking during pregnancy in rats. The fetal average birth weight and the erythrocyte deformability were found to be significantly reduced in the smoke-exposed group compared with the control group. However, there was a significant increase of blood viscosity (at both shear rates), Hb, Ht, MCV, MCH levels and the erythrocyte fragility in the smoke-exposed group in comparison with the control group. After the mother-rats were given PBCRS and RQRS prescriptions during gestation, the fetal average birth weight and erythrocyte deformability were markedly increased. The blood viscosity, Hb, Ht, MCV, MCH levels and erythrocyte fragility of pregnant rats were decreased. No differences were found in the control group and the two treated groups. The electronic microscope observation of erythrocyte shape shows there were some protrusions on the surface of red cells in the smoke-exposed group. The protrusions were significantly reduced in the two treated groups, which was similar to the control group. The erythrocyte deformability, the blood viscosity, Hb, Ht, MCV, MCH levels indicate that there was a significant correlation between them and the fetal average birth weight respectively. This study indicates that blood stasis is one of the pathogenetic mechanisms of asymmetrical IUGR and that the PBCRS recipe could improve intrauterine growth environment of fetal which could treat and prevent IUGR in obstetrics.

Animals↗

PubMed1989

[Human selenium deficiency during total parenteral nutrition support (a case report)].

There is accumulating evidence that selenium plays an important role in human nutrition. We have seen an increasing number of reports of selenium deficiency in patients after long-term Total Parenteral Nutrition (TPN) support, such as Home Parenteral Nutrition support. There had been no such patient reported in China until now. A sever multiple gastro-intestinal external fistulae patient was admitted in early Oct. 1985. His intestinal fluid loss was about 4-6 liters/day and he was a resident of a town where many people have low serum selenium levels. After two weeks of high calorie, high nitrogen TPN support, his serum selenium levels were 7.14, 6.25, and 7.97 micrograms/L (around the 3rd and 4th weeks of such TPN support). The patient also showed a higher heart rate and pain in the thigh muscle. After 4 weeks of selenium supplement, his serum selenium levels and heart rate were back to normal and the muscle pain disappeared.

Adolescent↗

PubMed1988

Bioavailability of soil-bound TCDD: oral bioavailability in the rat.

The implications to the public health of trace amounts of 2,3,7,8-TCDD in the environment are under evaluation by regulatory agencies in the United States and Western Europe. One major consideration in such evaluations is the contribution to human exposure via ingestion of TCDD-contaminated soil. An 80% figure is under consideration by some regulators for estimated human exposure. A contractor for one agency has, in fact, used a value of 100% bioavailability for estimating human bioavailability. Several studies have investigated the oral bioavailability of TCDD from contaminated soil in animals. Most have reported estimates of 25-50%, although one has reported less than 0.5 and 85%, depending on the source of the contaminated soil. This paper reports an oral bioavailability of approximately 43% in the rat dosed with three environmentally contaminated soil samples from Times Beach, Missouri. This figure did not change significantly over a 500-fold dose range of 2 to 1450 ng TCDD/kg of body weight for soil contaminated with approximately 2, 30, or 600 ppb of TCDD. The relevance of animal oral bioavailability data for the human remains to be evaluated. However, since regulatory agencies use animal data for extrapolating to humans, the 43% or 25-50% figure would be more accurate than the 80 or 100% estimates.

Administration, Oral↗

PubMed1988

Bioavailability of soil-bound TCDD: dermal bioavailability in the rat.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), an unwanted by-product formed during the manufacture of hexachlorophene and phenoxyherbicides, has been found as an environmental contaminant in many U.S. and Western European sites. This study examines in the rat the degree of dermal absorption of TCDD bound to soil. Such information would assist regulatory agencies in evaluating the degree of exposure of humans who come in contact with TCDD-contaminated soil. Several parameters which may influence dermal absorption were studied, including TCDD dose, duration of contact, presence of crankcase oil as a co-contaminant, and environmentally contaminated vs laboratory-prepared soil. The dermal penetration of TCDD following 4 hr of contact with skin was approximately 60% of that following 24 hr of contact (P less than or equal to 0.05). Following 24 hr of contact with the skin, the degree of dermal uptake of TCDD contaminated soil was approximately 1% of the administered dose. Under the conditions of the present study, the degree of uptake does not appear to be influenced to any significant extent by the concentration of TCDD on soil, the presence of crankcase oil as co-contaminants, or by environmentally vs laboratory-contaminated soil. Although a number of parameters examined in this study did not significantly influence the degree of dermal absorption of TCDD in the rat following 24 hr of contact with the contaminated soil, the unqualified use of the 1% value to estimate human exposure would overestimate human exposure, since there is general agreement among researchers that rat skin tends to be more permeable than human skin to highly lipid-soluble compounds such as TCDD.

Animals↗