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Biomedical subjects

Z Feng

Publications and source records attributed to Z Feng.

At least 199 records · Page 11Linked to original sources
PubMed1996

Work site-based cancer prevention: primary results from the Working Well Trial.

OBJECTIVES: This paper presents the behavioral results of the Working Well Trial, the largest US work site cancer prevention and control trial to date. METHODS: The Working Well Trial used a randomized, matched-pair evaluation design, with the work site as the unit of assignment and analysis. The study was conducted in 111 work sites (n = 28,000 workers). The effects of the intervention were evaluated by comparing changes in intervention and control work sites, as measured in cross-sectional surveys at baseline and follow-up. The 2-year intervention targeted both individuals and the work-site environment. RESULTS: There occurred a net reduction in the percentage of energy obtained from fat consumption of 0.37 percentage points (P = .033), a net increase in fiber densities of 0.13 g/1000 kcal (P = .056), and an average increase in fruit and vegetable intake of 0.18 servings per day (P = .0001). Changes in tobacco use were in the desired direction but were not significant. CONCLUSIONS: Significant but small differences were observed for nutrition. Positive trends, but no significant results, were observed in trial-wide smoking outcomes. The observed net differences were small owing to the substantial secular changes in target behaviors.

Cross-Sectional Studies↗
PubMed1996

Regulation of a physiological apoptosis: mouse mammary involution.

Continuous milk production during lactation is dependent on a complex interplay of lactogenic hormones and the suckling stimulus exerted by the young. Involution can be initiated in the mouse mammary gland at any stage of lactation by removing the pups; involution then remains reversible for about 30 to 36 h. Involution in the mouse mammary gland is characterized by a massive loss of secretory epithelial cells from programmed cell death. The nuclear activation of protein kinase A and transcription factor activator protein 1 precede the irreversible phase of involution that is characterized by internucleosomal DNA fragmentation. Activation of activator protein 1 and fragmentation of chromosomal DNA can be prevented by lactogenic hormone treatment in explant cultures derived from mammary tissue at lactation. The elevation in activator protein 1 coincides with the epithelial expression of sulfated glycoprotein 2, a potential target gene of activator protein 1. Programmed cell death in the mammary gland is associated with the expression of the growth arrest gene, gas-1, and the integrin-associated protein gene, IAP, which codes for a putative Ca2+ channel that is dependent on integrin. Their potential roles during involution are discussed.

Animals↗
PubMed1996

Long-term cryopreservation of bone marrow for autologous transplantation.

Little is known about the effect of long-term cryopreservation on the viability of hematopoietic stem cells (HSC) or on the success of autologous bone marrow transplantation. Although progenitor cell assays such as culture of CFU-GM after thawing can be predictive of engraftment, the most rigorous assay for the cryosurvival of HSC is engraftment after reinfusion of stem cells. We retrospectively evaluated the engraftment data for 36 patients with hematologic malignancies or solid tumors treated at the Fred Hutchinson Cancer Research Center between 1981 and 1993 who received bone marrows stored for 2 years or more. The median duration of cryopreservation for this study group was 2.7 years (range 2.0-7.8). Ninety-seven percent of patients in the study group achieved a granulocyte count of > or = 0.5 x 1.0(9)/1 at a median of 19 days (range 10-115) vs 86% of control group (selected by diagnosis and date of storage) at a median of 20 days (P = 0.14). Seventy percent of patients in the study group achieved a platelet count > or = 20 x 10(9)/1 at a median of 27 days (range 9-69) vs 74% of control group at a median of 23 days (P = 0.47). Also, samples of 28 marrows cryopreserved for a median of 4.4 years (range 2.0-7.8) were cultured to determine if a loss of hematopoietic progenitors relative to duration of storage could be detected. The storage length was not predictive for the quantity of colonies formed (P = 0.57 for BFU-E-derived colonies; P = 0.65 for CFU-GM-derived colonies). We found no consistent detrimental effect of long-term cryopreservation on the success rate of autologous bone marrow transplantation. This report confirms previous reports that marrow cells cryopreserved for several years are capable of engrafting. Therefore, bone marrow cells may be stored at an early appropriate time before the side-effects of multiple cycles of chemotherapy and radiotherapy on hematopoietic tissues are incurred.

Adolescent↗
PubMed1996

Lactose metabolism and time to pregnancy.

OBJECTIVE: To investigate whether, in the absence of galactosemia, relatively high intestinal lactase activity or low activity of an enzyme involved in galactose catabolism reduces fertility, as it does in the presence of galactosemia. DESIGN: Retrospective cohort study. SETTING: Healthy women selected from the community. PATIENTS: Fifty-three married women. INTERVENTION: Urinary galactose after an oral lactose challenge (a measure of intestinal lactase activity), erythrocyte galactose-1-phosphate uridyltransferase (transferase) activity, and transferase polymorphisms by isoelectric focusing. MAIN OUTCOME MEASURE: Pregnancy rate (number of pregnancies divided by number of months at risk) in the 12 months after stopping use of birth control to become pregnant. RESULTS: Relatively high urinary galactose was not related to a decreased rate of pregnancy during the first 12 months (> or = 24.6 compared with < or = 14.3 mg: relative risk [RR] = 1.9; 95% confidence interval [CI] = 0.86 to 4.0). Relatively high transferase activity was not related to an increased rate of pregnancy (> or = 19.5 compared with < or = 17.2 mumol/h per g hemoglobin: RR = 1.1; 95% CI = 0.56 to 2.4). Low-activity transferase polymorphisms were not related to a decreased rate (RR = 1.2; 95% CI = 0.58 to 2.5). CONCLUSION: Our study does not support the hypothesis that the biologic variation in galactose metabolism that exists in the general population influences infertility.

Adolescent↗
PubMed1996

Leukotriene B4 modulates in vivo expression of delayed-type hypersensitivity by a receptor-mediated mechanism: regulation by lipoxin A4.

Leukotriene B4 (LTB4) is a potent proinflammatory arachidonic acid metabolite whose actions are mediated by specific receptors. Recent characterization of a high-affinity LTB4 receptor on the surface of guinea pig CD4+ T lymphocytes prompted examination of a possible role of LTB4 in modulating in vivo expression of delayed-type hypersensitivity (DTH) to tuberculin (PPD). In the absence of PPD, intradermal injections of LTB4 or LTB4/LTD4 receptor antagonists did not elicit delayed-onset erythema at 24 h. When injected together with PPD, LTB4 (1 fmol to 1 pmol) caused a significant 25 to 30% decrease in DTH expression, whereas LTB4 receptor antagonists SC-41930, LY-223982, ONO-4057 (0.1-10 nmol), caused a highly significant (P < .01) 25 to 50% increase. The effect of SC-41930 on DTH expression was inhibited by a 10-fmol dose of LTB4. LTD4 receptor antagonist LY-171883 had no effect on DTH expression. Lipoxin A4 (LXA4) interferes with binding of LTB4 to T lymphocytes or neutrophils by reducing LTB4 receptor density. It caused a small but significant enhancement of DTH expression at 1-nmol doses when injected with PPD. Lipoxin B4 had no effect. Enhancement or inhibition of grossly visible delayed skin responses to PPD by LTB4. LTB4 receptor antagonists or LXA4 was not associated with qualitative or quantitative changes in superficial or deep dermal mononuclear cell infiltrates at the reaction site. We conclude that LTB4 modulates visible expression of DTH in vivo by a receptor-mediated mechanism.

Animals↗
PubMed1996

[Interventional treatment for partial stenosis or occlusion type of Budd-Chiari syndrome].

It is difficult to deal with interventional management of partial stenosis or occlusion type of Budd-chiari syndrome and manage the hepatic veins associated with inferior vena cave occlusion. Puncture, PTA and vascular stent plant were used to treat 12 patients with partial stenosis or occlusion of Budd-chiari syndrome. The procedures were successful. Either the symptoms or signs disappeared or relieved after operation. No severe side effects occurred. Follow-up for 1.5 through 26 months (average 8.5 months) revealed that the early or middle results were gratifying. There may be danger during operation, but perfect skills and adequate clinical anatomic knowledge help avoid severe side effects.

Adult↗
PubMed1995

Lactose and galactose intake and metabolism in relation to the risk of epithelial ovarian cancer.

It has been suggested that aspects of lactose consumption and metabolism favoring a relatively high tissue level of galactose-1-phosphate may predispose women to ovarian cancer. The authors sought to examine this hypothesis in a study of 108 18- to 74-year-old Caucasian residents of a three-county area of western Washington who were diagnosed with stage I ovarian cancer during 1989-1991, and 108 age- and race-matched controls. Lactose and galactose intake, measured using a food frequency questionnaire, had been hypothesized to increase risk, but were somewhat lower among the cases than among the controls (75th percentile of lactose intake vs. 25th: odds ratio (OR) = 0.80, 95% confidence interval (Cl) 0.52-1.2; of galactose intake: OR = 0.71, 95% Cl 0.48-1.1). Intestinal lactase activity, also hypothesized to have a positive relation with ovarian cancer occurrence, was measured with an oral lactose challenge followed by determination of urinary galactose; no evidence that it was related to the disease was found (75th percentile of excreted galactose vs. 25th: OR = 0.87, 95% Cl 0.62-1.2). Galactose-1-phosphate uridyltransferase (transferase), the enzyme responsible for the metabolism of galactose-1-phosphate, was measured in erythrocytes; no deficit in cases was observed (75th percentile of transferase activity vs. 25th: OR = 1.3, 95% Cl 0.80-2.1). There was also no excess of cases carrying low-activity genetic variants of the transferase enzyme (lower-activity variants vs. higher-activity variants: OR = 0.61, 95% Cl 0.21-1.7). These results do not support the hypothesis that aspects of lactose and galactose intake and metabolism have a bearing on the etiology of ovarian cancer.

Adult↗
PubMed1995

Design and synthesis of piperidine-3-carboxamides as human platelet aggregation inhibitors.

A detailed structure-activity analysis was carried out using eight 1-alkyl(aralkyl)nipecotamides (type 5), 33 bis-nipecotamidoalkanes and aralkanes (type 6), and 7 N,N'-bis(nipecotoyl)-piperazines (type 7) as inhibitors of human platelet aggregation. Steric factors played an important role in determining the activity of type 5 compounds possessing an an appropriate degree of hydrophobic character. Types 6 and 7 compounds were more potent than the corresponding type 5 molecules. Hydrophobic character appeared to influence the activity of type 6 compounds. A 3-substituent on the piperidine ring was necessary for antiplatelet activity; the substituent should be preferably an amide with its C attached directly to the ring. 3,5-Disubstitution and 2-substitution led to a decline in activity. Optimal activity was attained when the two nipecotoyl ring N atoms were connected by an aralkyl group, and separated by approximately 7 A. It is suggested that van der Waals forces and pi interactions may govern the inhibitor-platelet interaction. The most potent type 6 inhibitor was alpha,alpha'-bis[3-(N-ethyl-N-butylcarbamoyl)piperidino]-p-xylene (6i). The most potent type 5 compound was 1-decyl-3-(N,N-diethylcarbamoyl)piperidine (5a). Any substitution on the piperazine ring of type 7 compounds led to a decline in activity, the most active analog being N,N'-bis(1-decylnipecotoyl)piperazine (7a). It is suggested that nipecotamides interact with anionic platelet sites located 7 A from each other and connected by a hydrophobic well.

Adult↗
PubMed1995

The Working Well Trial: baseline dietary and smoking behaviors of employees and related worksite characteristics. The Working Well Research Group.

BACKGROUND: The Working Well Trial, the largest randomized worksite health promotion trial to date, tests the effects of cancer prevention and control interventions on dietary and smoking behaviors of employees and the worksite environment. The trial is a 5-year cooperative agreement conducted in 57 matched pairs of worksites in 16 states by four study centers, a coordinating center, and the National Cancer Institute. The dual aims of this paper are to: (a) present a baseline description of the dietary and smoking habits of 20,801 employees, who are predominantly blue-collar workers; and (b) describe the social and physical environments of their worksites that may facilitate or hinder health behavior changes. METHODS: The self-administered baseline survey of individuals consisted of a core set of questions common across all study centers on diet and smoking. The organizational survey consisted of eight instruments administered via interviews with key informants in each worksite. Continuous variable were analyzed by a mixed linear model and binary data were analyzed by the Generalized Estimating Equation. RESULTS: The population represented is largely male (67.5%) and blue collar (53.5%). Mean levels of fat and fiber intakes were close to the national averages (36.6% of calories as fat and 13.1 g of fiber). Smoking prevalence (25.2%) was slightly lower than the national average. The worksites had a high level of health promotion activities (42% had nutrition programs, 53% had smoking control programs), but lacked environmental support for dietary behavior change and perceived support for smoking cessation. CONCLUSIONS: These findings replicate and extend previous research results to a large sample of diverse, largely blue-collar worksites. In addition the baseline results lay a foundation for the development of new insights into the relationship between individual and organizational level variables that may interact to influence behavioral and cultural norms.

Adult↗
PubMed1995

Psychosocial correlates of healthful diets: baseline results from the Working Well Study.

BACKGROUND: This report examines psychosocial factors related to selection of healthful diets. Understanding why people select healthful diets can lead to rational design and evaluation of nutrition intervention programs. METHODS: Data are from 16,287 respondents to the baseline survey for the Working Well Trial, a randomized, controlled trial of worksite-based health promotion. The psychosocial constructs we measured were predisposing factors (beliefs, perceived benefits, and motivation; 5 items, Cronbach's alpha = 0.65) and enabling factors (barriers, norms, and social support; 6 items, Cronbach's alpha = 0.57). The healthful diet outcomes were intakes of fat, fiber, and servings of fruits and vegetables (from a food frequency questionnaire) and intention and self-efficacy to decrease fat and increase fruits and vegetables. RESULTS: Based on a 5-point scale (1 = low to 5 = high), the mean predisposing factor scale score was much higher than the enabling factor scale score (3.77 vs 2.50, P < 0.001). Comparing respondents in the highest category of the predisposing scale to those in the lowest, mean percentage of energy from fat was 22.4% lower (-9 percentage points), fiber was 85.2% higher (+4.6 g/1,000 kcal), and fruits and vegetables were 100% higher (+1.6 servings/day) (all trends, P < 0.001). Associations were similar, but much weaker, for the enabling scale. Multiple regression models, which included covariates related to diet and the predisposing and enabling scales, explained a total of between 13 and 26% of the variance in diet and intention to change diet. After control for covariates, the predisposing scale remained a significant and strong predictor of diet and intention to change diet but the enabling scale explained small and nonsignificant amounts of variance. CONCLUSIONS: Predisposing factors are strong predictors of current diet and intention to change diet. Final results from the Working Well Trial will provide more information on whether enabling factors can be enhanced by intervention and whether these changes result in healthier eating patterns.

Adult↗
PubMed1995

Kinetic analysis of impaired work-cost performance in jaundiced rabbit liver.

Impairment of energy metabolism was studied in jaundiced rabbit liver by kinetic analysis of energy transfer function. Free cytosolic ADP (ADPf), as calculated from the measured components of the glyceraldehyde-3-phosphate dehydrogenase and 3-phosphoglycerate kinase/lactate dehydrogenase reactions, decreased from the control value of 48.1 to 37.0 microM at 24 h after bile duct ligation. The maximal velocity (Vmax) of ATP synthesis, as measured by state 3 respiration of isolated mitochondria, decreased from the control value of 62.1 to 38.3 nmol ATP synthesized per min per mg mitochondrial protein, while the Michaelis constant for ADP (Km) decreased from the control value of 19.2 to 12.8 microM. ATP synthesis velocity in vivo }v: Vmax/[1 + (Km/[ADPf])], as calculated by Vmax, Km and ADPf, decreased from the control value of 44.4 to 28.5 nmol ATP synthesized per min per mg mitochondrial protein. Delta v/delta ADPf(delta v/delta ADPf: Vmax.Km/(Km + [ADPf])2), which indicates work-cost performance of the liver, decreased from the control value of 0.263 to 0.198. Biochemical output of the liver, as measured by hippurate synthesis from benzoate, decreased from the control value of 98.4 to 32.7 mg/h. These results indicate that synergistic decreases in ADPf, Vmax, v and delta v/delta ADPf take place in the course of deterioration of mitochondrial ATP synthesis and work output in jaundiced liver.

Adenosine Diphosphate↗
PubMed1995

Mutagenesis of rat dopamine beta-hydroxylase: examination in cell-free system.

Dopamine beta-hydroxylase (DBH; EC 1.14.17.1) exists as membrane-bound and soluble forms in neurosecretory vesicles. The features of DBH required for glycosylation and incorporation into membranes were studied in a cell-free system. Translation of full-length DBH with microsomal membranes generated two glycosylated products (GH and GL) depending on the magnesium concentration. Carboxyl-terminal, in contrast to amino-terminal, truncations gave translation products that were glycosylated by microsomal membranes. Site-directed mutants were generated with the second AUG codon and the region of a putative signal sequence cleavage site modified. Translation without membranes indicated that the second AUG is not used to initiate translation. The mutant with Glu41-->Leu41 and Ser43-->Thr43 yielded only the GH form with membranes, whereas mutation of Ser43-->Ala43 generated both GH and GL forms. Both glycosylated forms comigrated with the microsomal membranes on sucrose gradients. Endoglycosidase H digestion indicated that the differences between the GH and GL forms are not due to the sugar moiety. The results suggest a role for cleavage of a signal sequence in the formation of different forms of DBH. The possibility that these mutations change the secondary structure near the signal cleavage site, affecting processing, is discussed.

Amino Acid Sequence↗
PubMed1995

Glucocorticoid and progesterone inhibit involution and programmed cell death in the mouse mammary gland.

Milk production during lactation is a consequence of the suckling stimulus and the presence of glucocorticoids, prolactin, and insulin. After weaning the glucocorticoid hormone level drops, secretory mammary epithelial cells die by programmed cell death and the gland is prepared for a new pregnancy. We studied the role of steroid hormones and prolactin on the mammary gland structure, milk protein synthesis, and on programmed cell death. Slow-release plastic pellets containing individual hormones were implanted into a single mammary gland at lactation. At the same time the pups were removed and the consequences of the release of hormones were investigated histologically and biochemically. We found a local inhibition of involution in the vicinity of deoxycorticosterone- and progesterone-release pellets while prolactin-release pellets were ineffective. Dexamethasone, a very stable and potent glucocorticoid hormone analogue, inhibited involution and programmed cell death in all the mammary glands. It led to an accumulation of milk in the glands and was accompanied by an induction of protein kinase A, AP-1 DNA binding activity and elevated c-fos, junB, and junD mRNA levels. Several potential target genes of AP-1 such as stromelysin-1, c-jun, and SGP-2 that are induced during normal involution were strongly inhibited in dexamethasone-treated animals. Our results suggest that the cross-talk between steroid hormone receptors and AP-1 previously described in cells in culture leads to an impairment of AP-1 activity and to an inhibition of involution in the mammary gland implying that programmed cell death in the postlactational mammary gland depends on functional AP-1.

Animals↗
PubMed1995

[The founding of Baoding Medical College].

Baoding Medical College, an earlier institution of combining western and traditional Chinese medicine, played an active role in the development of combined medicine. This paper introduces its historical background, regulations for teaching program and student management. This might be helpful to contemporary educational reform.

China↗
PubMed1995

Expression and activity of cell cycle regulators during proliferation and programmed cell death in the mammary gland.

In the mammary gland distinct phases of proliferation, differentiation and programmed cell death of epithelial cells occur at defined stages of development. Here we show that the expression and activity of cell cycle regulators during normal and preneoplastic proliferation and programmed cell death are remarkably similar. In all cases we found elevated levels of a protein kinase A activity and of transcription factor AP-1, cFos and JunD being the major components of the AP-1 DNA binding complex. A correlation between cFos and JunD expression and chromosomal DNA fragmentation during programmed cell death was observed. Several genes associated with G1, including cyclin D1, D2 and D3 and c-fos, c-jun, junB, JunD, c-myc and p53, are induced in proliferating and in apoptotic mouse mammary tissue. Whereas the expression of these genes correlated with active proliferation of epithelial cells in terminal end buds during puberty, very little proliferation or DNA synthesis, but, instead, extensive apoptosis of epithelial cells, was observed during involution. Our results suggest that a G1-like state is associated with programmed cell death of mammary epithelial cells in vivo and that apoptosis occurs without S-phase induction.

Journal Article↗
PubMed1995

Rabies viral antigen in human tongues and salivary glands.

Lingual and major salivary tissue samples from three cases of rabies were stained with the immunoperoxidase (ABC) technique. All tissue blocks had been embedded in paraffin 4-10 years before. The first antibody used was monoclonal antirabies nucleocapsin (N) mouse antibody (HAM). Four out of five pieces of tongue from two cases showed a large amount of granular staining indicating rabies antigen (RVAg) inside serous glandular cells, terminal nerves, muscle cells and covering epithelial cells including taste cells. In the tissue probes from the third case only minimal granular staining was found, probably due to complete absence of the serous gland. In contrast to the tongue, only a little weakly reacting material was found in 4 out of 9 probes of salivary gland, either in acini or in nerve fibres. The amount of RVAg is evidently much greater in the human tongue than in major salivary glands, whereas major salivary glands from infected dogs, foxes and skunks reportedly contain much RVAg. As the human tongue's serous gland appears to be a preferred location for RVAg, it may be a source of oral infection.

Adolescent↗