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Biomedical subjects

S Deng

Publications and source records attributed to S Deng.

At least 37 records · Page 2Linked to original sources
PubMed2001

Cigarette use in adolescents: the Cardiovascular Health in Children and Youth Study.

Tobacco is the leading cause of preventable death in the United States, and its use is increasing in adolescents. To determine the interventions needed to prevent the initiation of smoking, it is important to know the factors related to tobacco use by adolescents. In this study the following factors related to cigarette use were examined: age, gender, ethnicity, self-esteem, physical activity, parental smoking, and socioeconomic status. Participants were 1,207 youth completing a written survey for the Cardiovascular Health in Children and Youth Study (CHIC II). Participants ranged in age from 10 to 15 years, with a mean age of 12.2 years; 64.2% were White, 24.0% Black, 5.8% Hispanic, and 6.0% other races. White and Hispanic youth and youth of other races had significantly higher rates of smoking than did Black youth. Significant risk factors for smoking were: higher grade in school, White race, and for girls only, lower self-esteem. In White youth those in the lowest socioeconomic status were most likely to be current and experimental smokers. Smoking was as common in girls as in boys at these ages. Multivariate analysis showed that neither physical activity nor parental smoking were significant predictors of smoking behaviors. These results suggest that smoking prevention programs for adolescents should specifically target White and Hispanic youth and those from families with low socioeconomic status. In addition, these interventions should include ways to increase self-esteem in girls.

Adolescent↗
PubMed2001

Cloning and characterization of a second acid phosphatase from Sinorhizobium meliloti strain 104A14.

Sinorhizobium meliloti has two nonspecific periplasmic acid phosphatases. The NapD enzyme has been previously described, and a second acid phosphatase, NapE, is described in this report. NapE was partially purified from an S. meliloti napD mutant and characterized with respect to molecular mass and substrate range. As predicted from SDS-PAGE analysis, the subunit molecular mass of NapE is approximately 35.8 kDa and gel filtration experiments estimated the native molecular mass to be approximately 70 kDa, indicating that the active enzyme is a homodimer. NapE demonstrated significant activity with p-nitrophenyl phosphate, phenyl phosphate, and alpha-naphthyl-phosphate. The pH optimum was between 4.5 and 5.0. The gene encoding NapE was also sequenced and the inferred amino acid sequence from the predicted ORF was found to be 60% identical and 75% similar to that encoded by napD. An S. meliloti napE mutant was constructed and assessed for symbiotic competence. This mutant did not differ from the wild-type parent strain in nodulation and symbiotic efficiency.

Acid Phosphatase↗
PubMed2001

Leptin and obesity in mother-child pairs.

Defects in the leptin gene or the leptin receptor may be a genetic cause of obesity, but little is known about the familial associations of leptin and obesity. This study compared plasma leptin and measures of obesity in a sample of 248 subjects (124 mother-offspring pairs); 34% were African American and 66% were white. Youth were aged 12 to 16 years. Plasma leptin and body mass index (BMI) were higher in mothers than in their offspring and, among the offspring, higher in girls than boys, even after correcting for BMI or body fat. Racial differences in leptin were present in both mothers and youth when adjusting for percentage body fat but disappeared when adjusting for BMI. In univariate analyses of the associations between mothers and offspring, BMI was associated with leptin in all groups but was most strongly associated in white pairs and in mother-son pairs. In multiple regression analyses, when adjusting for BMI, significant predictors of leptin levelfor the boys and girls together were gender, BMI, and pubertal status of the offspring; in girls only BMI was significant (R2 = 0.72), and in boys the significant predictors were their BMI (R2 = 0.66) followed by their pubertal status (R2 = 0.06) and the leptin level of their mothers (R2 = 0.02). When adjusting for body fat, the predictors were the offspring's percentage bodyfat (R2 = 0. 67) and mother's leptin (R2 = 0.03), with similar results in gender-specific analyses. The authors conclude that leptin levels of youth are most closely associated with their degree of obesity or body fat; mother's leptin and, for boys only, pubertal status also play a small role. Although the small association between maternal leptin on leptin in their offspring could be due to either heredity or shared environment, the results of this study suggest that individual obesity and environmental factors are important predictors of leptin levels in children.

Adolescent↗
PubMed2001

Titer-dependent antagonism of cocaine following active immunization in rhesus monkeys.

Immunization may be a useful pharmacokinetic antagonist therapy for cocaine users. Three rhesus monkeys were immunized with a cocaine:bovine serum albumin conjugate in alum and later with complete and incomplete Freund's adjuvants. Monkeys developed cocaine-binding antibodies (as measured by enzyme-linked immunosorbent assay) after immunization with alum; greater antibody titers developed after immunization with Freund's adjuvants. The response rate-decreasing effect of cocaine diminished in proportion to antibody titer; there was no substantial change in the rate-decreasing effect of bupropion. Plasma cocaine concentrations increased in proportion to antibody titer. Immunizations were well tolerated and had no effect on response rates. These data suggest that the antibody response to a cocaine antigen can produce a specific pharmacokinetic shift in cocaine distribution sufficient to antagonize a behavioral effect of the drug, and can do so with minimal side effects.

Animals↗
PubMed2001

[The influence of recombinant human growth hormone on the metabolism of glucose and protein in severely burned patients].

OBJECTIVE: To investigate the influence of recombinant human growth hormone (rhGH) on the metabolism of glucose and protein in severely burned patients. METHODS: The serum levels of total protein and albumin and the incidence of hyperglycemia in 24 cases of severely burned patients treated by rhGH were determined and compared with those in patients without rhGH treatment (control group). RESULTS: The serum levels of total protein (TP) and albumin in burned patients after being treated by rhGH were much higher than those before treatment and those in control group. The blood level of glucose increased within 2 weeks, especially 1 week postburn. The incidences of hyperglycemia were 52.38%, 50.24% and 20% on 0 similar 3, 4 similar 7 and 8 similar 14 postburn days (PBDs), respectively. And the incidences of hyperglycemia were 100%, 50% and 0% when the administration of rhGH started within 1, 2 and after 2 weeks respectively. CONCLUSION: The systemic protein synthesis in severely burned patients could be accelerated by the use of rhGH. But early administration of rhGH in burned patients could affect blood sugar level obviously. And the optimal time to give rhGH is 2 weeks after burn injury.

Adult↗
PubMed2001

[Analysis of main chemical composition in hydrogenated rosin from Zhuzhou].

The acid fraction, the main part of the hydrogenated rosin produced by Zhuzhou Forest Chemicals Plant of China, was separated from neutral fraction by modified DEAE-Sephadex ion exchange chromatography and analyzed with GC-MS-DS technique by using DB-5 capillary column. Six dihydroabietic-type resin acids, four dihydropimaric/isopimaric-type resin acids and four tetrahydroabietic-type resin acids were identified. The hydrogenated rosin is composed mainly of 8-abietenoic acid, 18-abietanoic acid, 13-abietenoic acid, 8 alpha, 13 beta-abietanoic acid, 13 beta-8-abietenoic acid and 8-isopimarenoic acid etc.

Carboxylic Acids↗
PubMed2000

The axis of interleukin 12 and gamma interferon regulates acute vascular xenogeneic rejection.

Recent advances using transgenic animals or exogenous complement inhibitors have demonstrated prevention of hyperacute rejection of vascularized organs, but not graft loss due to acute vascular rejection. Using various wild-type and cytokine-deficient mice strains, we have examined the mechanisms of acute vascular rejection. C57BL/6 mice deficient in interleukin12 or gamma interferon showed faster acute vascular rejection than did wild-type mice. Furthermore, mice defective in B-cell development showed no acute vascular rejection. These results demonstrate that the axis of interleukin 12 and gamma interferon provides a survival advantage in vascularized xenografts by delaying or preventing acute vascular rejection caused by a B cell-dependent mechanism.

Acute Disease↗
PubMed2000

The influence of physical activity, socioeconomic status, and ethnicity on the weight status of adolescents.

OBJECTIVE: This study examined the effects of physical activity, television viewing, video game play, socioeconomic status (SES), and ethnicity on body mass index (BMI). RESEARCH METHODS AND PROCEDURES: The sample was 2389 adolescents, 10 to 16 years of age (12.7 +/- 1.0 years); 1240 (52%) females and 1149 (48%) males; 77% white and 23% African American; from rural (77%) and urban (23%) settings. BMI and skinfolds were directly assessed. All other data were obtained from questionnaires. RESULTS: Watching television on non-school days was related to being overweight (p < 0.005). However, when BMI analyses were adjusted for ethnicity and SES, there were no significant effects of television viewing on BMI (p > 0.061). Increased hours of video game play enhanced the risk of being overweight for both genders when analyses were adjusted for ethnicity and SES (p < 0.019). In males, participation in as little as one high-intensity physical activity 3 to 5 days a week decreased the ethnic- and SES-adjusted relative risk of being overweight (RR = 0.646; CI: 0.427 to 0.977). For females, the ethnic- and SES-adjusted relative risk for being overweight was not significantly altered by physical activity. The logistic analyses further indicated the influence of low SES and African American ethnicity overshadowed any direct effect of television or videos. DISCUSSION: Because weight status of male adolescents appears to be more related to exercise habits than to television or video game habits, increased participation in high-intensity exercise appears to be important. For females, neither videos nor exercise habits appear to be related to risk of being overweight. However, ethnicity and SES may be important factors that can influence body weight status, while television viewing may be of some importance. Thus, programs to reduce obesity in female adolescent should focus their efforts in lower SES communities.

Adolescent↗
PubMed2000

Changes in common activities of 3rd through 10th graders: the CHIC study.

PURPOSE: This study was a longitudinal examination of the change in both the activities done and the intensity of those activities from childhood to adolescence. METHODS: Common activities were assessed by questionnaire initially on 656 subjects from 21 elementary schools; 50.5% were female, 83.4% were Caucasian, 20.6% African-American, and 6.0% were other races. RESULTS: Girls more often reported sedentary activities overall. Weighted least squares analyses showed boys consistently reported more vigorous activities than girls (P < 0.0008). African-American girls reported fewer vigorous activities than Caucasian or other race girls (P = 0.027). Sedentary activities were more frequently reported with increasing age (X2 P < 0.001). The youngest African-American and Caucasian boys reported similar activity patterns. However, boys from other races reported more intense activities until sixth and seventh grades when African-American boys began reporting more sedentary activities than Caucasians or other races (P = 0.004). During sixth-eighth grades, Generalized Estimating Equations (GEE) models show that girls with more advanced pubertal status reported more sedentary activities than girls who were less developed (P < 0.0001). For high school girls, race was a marginally significant predictor (P = 0.05) of activity status. Neither race nor pubertal status were significant factors in activities chosen by middle school boys. However, for male high school students, Caucasians were more likely than African-Americans to report vigorous activities (P = 0.005). CONCLUSIONS: Variation in activities by race within gender suggests that establishing activity patterns in youth may be race-specific as well as gender-specific and must be accounted for in designing physical activity interventions. Also, pubertal maturation is a factor in activity choices in middle school girls.

Adolescent↗
PubMed2000

Animal models in xenotransplantation.

The severe shortage of donor organs has provided a strong impetus to push the investigation into the use of animal organs for humans. Xenotransplantation will not only benefit patients, but also represents a unique and potentially profitable business opportunity. However, there are many barriers to successful clinical xenotransplantation, including immunological barriers, physiological incompatibility, zoonosis and ethical concerns. This overview will focus on currently available animal models used in attempts to break through the immunological barriers to xenotransplantation. There are many advantages to using small animal, namely rodent, models in xenotransplantation research. For example, the use of the mouse model allows the use of knockout mice and careful dissection of rejection mechanisms at the molecular level. The following models can be used to study hyperacute rejection (HAR): guinea-pig-to-rat, mouse-to-rabbit, guinea-pig-to-mouse, rat-to-presensitised mouse and rat-to-alpha-Gal knockout mouse. The hamster-to-rat, mouse-to-rat and rat-to-mouse models are commonly used to study acute vascular rejection. Large animal models are complex and expensive, but they are more relevant to clinical xenotransplantation. Based on experiments using transgenic pig-to-primate models, HAR can be overcome. However, acute vascular rejection remains a major barrier at the present time. A pig cartilage-to-monkey model has been developed to study chronic rejection. Other novel models such as pig venous segment-to-monkey model and rat-to-primate model may represent viable options to study immunological barriers following xenotransplantation. Like many other medical breakthroughs, animal research will continue to make enormous contributions towards the eventual success of xenotransplantation.

Animals↗
PubMed2000

[Mixing of Cunninghamia lanceolata with Michelia macclurei and restoration of self-sustaining mechanism in G. lanceolata plantation].

The formation of self-sustaining mechanism is one of the major objectives for the sustainable management of plantations. In this study, the incorporation of different proportions of native Michelia macclurei into Cunninghamia lanceolata plantation was practiced to restore the degraded C. lanceolata plantation, and the comparison of nutrient cycling characteristics and soil nutrient concentrations was made among four types of plantation stand with different mixed rate of native M. macclurei representing four different restoration stages of degraded C. lanceolata plantations. With the increase of the proportion of M. macclurei in the plantation, the litterfall and returned nutrients N, P, K, Ca and Mg increased. The nutrient cycling efficiency increased significantly, e.g., that of N and Mg increased from about 0.1 for the degraded pure C. lanceolata plantation to above 0.5 for the pure M. macclurei plantation. Soil organic matter and nutrients also elevated. It is suggested that the self-sustaining mechanism of the C. lanceolata plantation forest gradually reformed as the proportion of native M. macclurei mixed in the plantation increased. The criteria to determine the proportion of native broad-leaved tree species mixed in C. lanceolata plantations for the purpose of sustainable management should be based on whether the self-sustaining mechanism was reformed and whether the soil nutrient status was improved.

Biomass↗
PubMed2000

[Bioproductivity of Castanopsis hysrix-Cyclobalanopsis glauca-Machilus pauhoi community in Huitong, Hunan].

Based on the mean DBH measurements of sample trees, the bioproductivity of subtropical Castanopsis hysrix-Cyclobalanopsis glauca-Machilus pauhoi community in Huitong, Hunan province was studied by regression analysis (y = a(D2.H)b). The results showed that the total biomass of the forest was 451.02 t.hm-2, and the component biomass of tree, shrub, liana and litter layer was 426.76, 17.76, 1.80 and 4.70 t.hm-2, respectively. The net production and average production of tree layer were 34.46 and 13.32 t.hm-2.yr-1, respectively.

Biomass↗
PubMed2000

[Mechanism of recombinant human growth hormone accelerating burn wound healing in burn patients].

OBJECTIVE: To investigate the mechanism of recombinant human growth hormone (rhGH) in acceleration of burn wound healing. METHODS: Thirty three severe burn patients were enrolled in this study and randomly divided into rhGH group (n = 18) and placebo control group (n = 15). The rhGH was administered subcutaneously in the dose of 0.1 mg . kg(-1) at 10 pm every evening in rhGH group for 14 days, while normal saline was used as a placebo in the control group. The serum concentration of GH and IGF-1 were assayed with ELISA method, and the proliferation index (PI) and S-phase fraction (SPF) of wound tissue was analyzed by flow cytometry (FCM). The expression of PCNA, EGFR and CK was assessed by immunohistochemical stains. RESULTS: Serum concentrations of GH and IFG-1 increased significantly after rhGH administration. The PI and SPF of wound tissue were obviously higher than those before rhGH administration and those in the control group. The expressions of PCNA, EGFR and CK was enhanced. In addition, the epidermis of healed wound was thicker in rhGH group than that in the control group. CONCLUSION: The application of rhGH in burn patients could improve the serum concentration of GH and IFG-1, promote DNA synthesis and PCNA and EFGR expression of epithelium, so that re-epithelialization of the burn wound could be accelerated.

Adult↗
PubMed2000

[Analysis of the factors related to the change of energy expenditure in burned patients].

OBJECTIVE: To analyze the factors related to the change of energy expenditure in burned patients. METHODS: Indirect calorimetry was employed to detect energy expenditure (EE) dynamically in 45 cases of burned patients and to analyze their change. RESULTS: EE increased immediately postburn and reached top level in about one week (11, 443.78 plus minus 3, 295.32) kJ/d. EE value was positively correlated to the size of burn area. EE was also correlated to the development of the disease. The EE variation happened in the early postburn stage. The degree of variation was positively correlated to the size of burn area. The EE value in patients with medium size burn and inhalation injury was higher than that without inhalation injury. Postoperative EE decreased obviously in patients with major burn who had undergone escharectomy. EE in male patients was higher than that in female. CONCLUSION: Postburn EE varied with some regularity, but was affected by burn depth and size, postburn time, inhalation injury, escharectomy, sex and individual difference.

Adolescent↗
PubMed1999

[Polymorphisms of five short tandem repeat systems in Chinese Han population in Chengdu]

OBJECTIVE: To get preliminary genotype and allele frequency distributions of D6S366, D6S477, D12S375, D12S391 and PLA2A loci in Chinese Han population in Chengdu area and to validate more short Tandem repeat (STR) systems for forensic application. METHODS: The polymerase chain reaction (PCR) was used. Five STR systems (D6S366, D6S477, D12S375, D12S391 and PLA2A) were amplified on DNA samples, which were extracted from 108 unrelated individuals EDTA-blood by Phenol/Chloroform method. The PCR products were analyzed by PAG vertical electrophoresis. RESULTS: Seven alleles were found at D6S366 locus, nine alleles at D6S477 locus, five alleles at D12S375 locus, nine alleles at D12S391 locus and seven alleles at PLA2A locus. No deviations from Hardy-Weinberg equilibrium were observed. The heterozygosities observed were 0.69, 0.78, 0.81, 0.68 and 0.79 for D6S366, D6S477, D12S375, D12S391 and PLA2A respectively. The chances of exclusion were 0.3621, 0.6004, 0.4581, 0.7014 and 0.5589 and the discriminating powers were 0.79, 0.93, 0.86, 0.96 and 0.91. CONCLUSION: All of the five loci in this study were useful markers for individual identification and paternity test and for genetics purposes.

Journal Article↗
PubMed1999

Gene therapy strategies to facilitate organ transplantation.

Organ transplantation is now the definitive therapy for many forms of end-organ disease, but chronic allograft rejection, the side effects of chronic immunosuppressive therapy and the severe donor organ shortage continue to limit its success. Gene therapy has the potential to prevent graft rejection by manipulating the immune response in the microenvironment of the graft or by facilitating the induction of tolerance. Genetic manipulation of stem cells to create transgenic and/or knockout animals that could serve as organ or cell donors could be combined with gene therapy approaches to overcome the problem of limited allogeneic donor organ supply.

Animals↗