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Biomedical subjects

W C Taylor

Publications and source records attributed to W C Taylor.

At least 19 recordsLinked to original sources
PubMed2001

The 3' non-coding region of a C4 photosynthesis gene increases transgene expression when combined with heterologous promoters.

The Me1 gene of the dicot Flaveria bidentis encodes NADP malic enzyme, which catalyses the decarboxylation reaction of C4 photosynthesis in bundle sheath cells. We have previously shown that the 3' non-coding region (Me1 3') controls quantitative expression of the gene. We wondered whether Me1 3' can increase expression when combined with heterologous promoters. We tested a highly expressed, constitutive promoter, the S4 promoter from subterranean clover stunt virus, and a highly expressed, leaf-specific promoter, the light-harvesting chlorophyll a/b-binding protein gene 3 (Lhcb3) promoter of Arabidopsis thaliana. Promoter-3'-end combinations were tested in transgenic C4 Flaveria plants and C3 tobacco. We found that Me1 3' increased expression of the gusA reporter gene several-fold in leaves of both species in combination with either of the promoters. In both cases Me1 3' does not alter the expression pattern for either promoter. We conclude that Me1 3' can be used as a transcription terminator to increase transgene expression in C3 dicot plants.

3' Untranslated Regions↗
PubMed2001

Quantitative regulation of the Flaveria Me1 gene is controlled by the 3'-untranslated region and sequences near the amino terminus.

The Me1 gene of Flaveria bidentis codes for the C4 isoform of NADP malic enzyme, which accumulates to a high-level only in bundle sheath cells. Previous experiments demonstrated that sequences at the 5' end of the gene control cell specificity whereas sequences at the 3' end are necessary for high-level expression. To localize quantitative regulator sequences, we have analysed a series of Me1 3' deletion constructs fused to the gusA reporter gene. We show that sequences within the 3'-untranslated region (3'-UTR) control quantitative levels of expression. Analysis of 5' promoter fusions demonstrated that high-level expression also requires sequences within the N-terminal coding region of the gene, suggesting possible interactions between the 3'-UTR and 5' coding regions. Cell-specific regulatory sequences are located in a different part of the 5' end of the gene, between 1023 bp upstream of the transcription start and the start of translation.

3' Untranslated Regions↗
PubMed2001

A new cyclobutane lignan from Cinnamomum balansae.

A new cyclobutane lignan, named cinbalansan (6), was isolated from the leaves of Cinnamomum balansae, along with five known compounds, 1,2-dimethoxy-4-(1-E-propenyl)benzene (1), 1,2-dimethoxy-4-(1-Z-propenyl)benzene (2), 1,2-dimethoxy-4-(2-propenyl)benzene (3), 3,4-dimethoxybenzaldehyde (4), and E-(3,4-dimethoxyphenyl)-2-propenal (5). The structure of cinbalansan was shown to be 1beta,2beta,3alpha,4alpha-1,2-dimethyl-3,4-bis(3,4-dimethoxyphenyl)cyclobutane by a combination of 1H-, 13C-NMR, and NOE- experiments and by direct analysis of the 1H-NMR spectrum by the method of X-application.

Acrolein↗
PubMed2001

New rearranged clerodane diterpenes from Tinospora baenzigeri.

Baenzigeroside B, a new rearranged clerodane diterpene glucoside, was isolated from the stems of Tinospora baenzigeri. The aglycone of baenzigeroside B, baenzigeride B (isolated as its acetate), was found together with baenzigeride A, baenzigerosides A and B in the leaves of the same plant. Baenzigeride B and baenzigeroside B are the first examples of a new class of rearranged clerodane diterpenes. The possible biogenesis of the compounds is discussed.

Acetylation↗
PubMed2000

Lanostanes and friedolanostanes from the pericarp of Garcinia hombroniana.

The CH2Cl2 extract from the pericarp of Garcinia hombroniana yielded three 17,14-friedolanostanes [(24E)-3alpha-hydroxy-17,14-friedolanostan-8, 14,24-trien-26-oic acid, methyl (24E)-3alpha,23-dihydroxy-17,14-friedolanostan-8,14,24 -trien-26-oate and methyl (24E)-3alpha,9,23-trihydroxy-17,14-friedolanostan-14,2 4-dien-26-oate] and two lanostanes [3beta- and 3alpha-hydroxy-23-oxo-9,16-lanostadien-26-oic acid]. The structure of (14E)-3alpha-hydroxy-17,14-friedolanostan-8,14,24-trie n-26-oic acid was determined using spectroscopic and X-ray analyses, while the structures of the other compounds were elucidated solely from analysis of spectroscopic data.

Magnoliopsida↗
PubMed2000

Using objective physical activity measures with youth: how many days of monitoring are needed?

PURPOSE: The purpose of this study was to establish the minimal number of days of monitoring required for accelerometers to assess usual physical activity in children. METHODS: A total of 381 students (189 M, 192 F) wore a CSA 7164 uniaxial accelerometer for seven consecutive days. To examine age-related trends students were grouped as follows: Group I: grades 1-3 (N = 92); Group II: grades 4-6 (N = 98); Group III: grades 7-9 (N = 97); Group IV: grades 10-12 (N = 94). Average daily time spent in moderate-to-vigorous physical activity (MVPA) was calculated from minute-by-minute activity counts using the regression equation developed by Freedson et al. (1997). RESULTS: Compared with adolescents in grades 7 to 12, children in grades 1 to 6 exhibited less day-to-day variability in MVPA behavior. Spearman-Brown analyses indicated that between 4 and 5 d of monitoring would be necessary to a achieve a reliability of 0.80 in children, and between 8 and 9 d of monitoring would be necessary to achieve a reliability of 0.80 in adolescents. Within all grade levels, the 7-d monitoring protocol produced acceptable estimates of daily participation in MVPA (R = 0.76 (0.71-0.81) to 0.87 (0.84-0.90)). Compared with weekdays, children exhibited significantly higher levels of MVPA on weekends, whereas adolescents exhibited significantly lower levels of MVPA on weekends. Principal components analysis revealed two distinct time components for MVPA during the day for children (early morning, rest of the day), and three distinct time components for MVPA during the day for adolescents (morning, afternoon, early evening). CONCLUSIONS: These results indicate that a 7-d monitoring protocol provides reliable estimates of usual physical activity behavior in children and adolescents and accounts for potentially important differences in weekend versus weekday activity behavior as well as differences in activity patterns within a given day.

Acceleration↗
PubMed2000

A review of correlates of physical activity of children and adolescents.

BACKGROUND: Understanding the factors that influence physical activity can aid the design of more effective interventions. Previous reviews of correlates of youth physical activity have produced conflicting results. METHODS: A comprehensive review of correlates of physical activity was conducted, and semiquantitative results were summarized separately for children (ages 3-12) and adolescents (ages 13-18). The 108 studies evaluated 40 variables for children and 48 variables for adolescents. RESULTS: About 60% of all reported associations with physical activity were statistically significant. Variables that were consistently associated with children's physical activity were sex (male), parental overweight status, physical activity preferences, intention to be active, perceived barriers (inverse), previous physical activity, healthy diet, program/facility access, and time spent outdoors. Variables that were consistently associated with adolescents' physical activity were sex (male), ethnicity (white), age (inverse), perceived activity competence, intentions, depression (inverse), previous physical activity, community sports, sensation seeking, sedentary after school and on weekends (inverse), parent support, support from others, sibling physical activity, direct help from parents, and opportunities to exercise. CONCLUSION: These consistently related variables should be confirmed in prospective studies, and interventions to improve the modifiable variables should be developed and evaluated.

Adolescent↗
PubMed1999

Correlates of physical activity in a national sample of girls and boys in grades 4 through 12.

Psychological, biological, social, and physical environmental variables were examined for their association with physical activity of young people. A national sample of 1,504 parents and children in Grades 4-12 were interviewed by telephone. Twenty-two potential determinants were assessed along with an 11-item child physical activity index (alpha = .76). Hierarchical multiple regressions were conducted separately for 6 age-sex subgroups. Percentage of variance explained ranged from 18% for boys in Grades 4-6 to 59% for girls in Grades 10-12. Three variables had strong and consistent associations with the child physical activity index that generalized across subgroups: use of afternoon time for sports and physical activity, enjoyment of physical education, and family support for physical activity. These 3 variables should be targeted for change to promote physical activity in all groups of young people.

Adolescent↗
PubMed1999

Childhood and adolescent physical activity patterns and adult physical activity.

PURPOSE: A major research priority is the influence of childhood and adolescent physical activity patterns on adult physical activity. The research in this area is inconsistent. Therefore, the purpose of this study was to evaluate the relationships among specific components of physical activity during childhood and adolescence and exercise habits in adulthood. METHODS: We analyzed preteen and teenage experiences, individual and team sports, and several psychosocial variables. One hundred and five male volunteers completed questionnaires about their current (estimated energy expenditure (EE)) and historic physical activity and a treadmill stress test. RESULTS: Based on correlations and regression analyses, without and with controlling for potentially confounding variables (treadmill run time and sum of skinfolds), the frequency of being forced to exercise and the frequency of being encouraged to exercise during the preteen years were inversely related to adult physical activity. Being forced to exercise during the preteen years was more related to participation in individual sports than to participation in team sports or both individual and team sports. CONCLUSIONS: Being forced to exercise during childhood may have potentially negative consequences for later activity. The findings indicate that experiences related to participation in activity during childhood and adolescence may influence adult physical activity. The implications of our findings are discussed and future research is recommended.

Adolescent↗
PubMed1999

Physical activity among African American and Latino middle school girls: consistent beliefs, expectations, and experiences across two sites.

Physical inactivity is a major public health concern. Low levels of physical activity are reported in many subgroups of women including adolescent girls. More data are needed to better understand factors related to physical activity participation in adolescent girls. Therefore, we explored adolescent girls' reasons for participating and not participating in physical activity. Two independent samples were taken in California and Texas; the total sample included thirty-four African American and Latino girls. Six focus groups were conducted by trained facilitators. Based on independent qualitative analyses, six replicated themes emerged from the focus groups. Fun, social support, and concern with body image facilitated participation in activity. In contrast, negative experiences in physical education classes, concerns about appearance after activity, and lack of opportunity impeded participation in activity. Overall, the girls showed an interest in physical activity and identified activity motivators and barriers. We discuss the implications of our findings for future research.

Adolescent↗
PubMed1998

Physical activity interventions in low-income, ethnic minority, and populations with disability.

BACKGROUND: Low-income, racial and ethnic minority, and populations with disabilities are more likely to be sedentary than the general population. Increasing physical activity in these groups is an important public health challenge. This report summarizes interventions that have targeted populations at risk for inactivity. METHODS: Computer and manual searches were performed to identify manuscripts published from 1983 to 1997. Interventions conducted in these populations in which physical activity was part of the intervention, and activity or cardiorespiratory fitness were outcome measures, were included in the review. RESULTS: Fourteen studies were identified. Most studies used pre-post or quasi-experimental designs. Common intervention features for the ten studies that included ethnic minority groups were community advisory panels, community needs assessments, and community members delivering the intervention. Eight studies reported a theoretical framework that guided the intervention. Increased physical activity was documented in two studies. Post-intervention follow-up was conducted in two studies; both reported no significant findings. Only four studies for people with disabilities were found; all four reported post-intervention physical activity change. CONCLUSION: Much work remains to develop effective interventions for these populations. Research that involves the community at all steps in the design and implementation of the intervention shows greatest promise for promoting behavior change. Future intervention studies should include: (1) rigorous experimental designs; (2) theoretically based interventions; and (3) validated assessment instruments to detect physical activity change.

Adolescent↗
PubMed1998

Biomedical risk factors for hospital admission in older adults.

OBJECTIVES: This study examines the influence of risk factors such as cigarette smoking, blood pressure, serum cholesterol, or chronic illness on frequency of hospital admission in a population-based sample. METHODS: Data from the National Health and Nutrition Examination Survey I Epidemiologic Followup Study for 6,461 adults aged 45 years and older were used to assess the influence of risk factors measured by interview, physical examination, and laboratory tests on frequency of hospital admission over a 12- to 16-year follow-up period. Cox proportional hazard regressions were estimated separately for men and women and for ages 45 to 64 years and 65 years and older. SUDAAN software was used to correct for clustering, stratification, unequal weighting, and multiple observations per respondent. RESULTS: Risk of hospitalization was higher for current but not former smokers (relative risk [RR] = 1.17-1.34 for different age-sex groups; P < 0.01), higher blood pressure (RR = 1.25-1.28 for ages 45-64; RR = 1.07-1.15 for ages 65 and older; P < 0.01), and lower serum albumin (RR = 1.08-1.14; P < 0.01). Diabetes, lung conditions, heart attack, and ulcer each were associated with higher risk in at least three of the four age-sex groups, as was arthritis among the middle-aged (45-64 years). Serum cholesterol was not associated with hospitalization. CONCLUSIONS: Chronic conditions with high morbidity as well as many factors associated with mortality are associated with a higher frequency of hospitalization.

Age Factors↗
PubMed1998

Modeling all-cause mortality: projections of the impact of smoking cessation based on the NHEFS. NHANES I Epidemiologic Follow-up Study.

OBJECTIVES: A model that relates clinical risk factors to subsequent mortality was used to simulate the impact of smoking cessation. METHODS: Survivor functions derived from multivariate hazard regressions fitted to data from the first National Health and Nutrition Examination Survey (NHANES I) Epidemiologic Followup Study, a longitudinal survey of a representative sample of US adults, were used to project deaths from all causes. RESULTS: Validation tests showed that the hazard regressions agreed with the risk relationships reported by others, that projected deaths for baseline risk factors closely matched observed mortality, and that the projections attributed deaths to the appropriate levels of important risk factors. Projections of the impact of smoking cessation showed that the number of cumulative deaths would be 15% lower after 5 years and 11% lower after 20 years. CONCLUSIONS: The model produced realistic projections of the effects of risk factor modification on subsequent mortality in adults, Comparison of the projections for smoking cessation with estimates of the risk attributable to smoking published by the Centers for Disease Control and Prevention suggests that cessation could capture most of the benefit possible from eliminating smoking.

Aged↗
PubMed1997

A triterpenoid saponin from Maesa ramentacea.

The structure of a piscicidal triterpenoid saponin (saponin A) isolated from the leaves of Maesa ramentacea has been shown to be 3-O-[[(alpha-rhamnopyranosyl (1-->2)-alpha-L-rhamnopyranosyl(1-->2)-beta-D-galactopyranosyl (1-->3)]-[beta-D-glucopyranosyl(1-->2)]-beta-D-glucuronopyranosyl] barringtogenol C21, 22-O-diangeloate. Extensive use was made of homo- and heteronuclear 2D NMR techniques.

Carbohydrate Conformation↗
PubMed1996

Analysis of Mutator-induced mutations in the iojap gene of maize.

The recessive nuclear mutation iojap (ij) in maize produces striped plants with normal chloroplasts in green sectors and poorly developed chloroplasts in the white sectors. The ij mutation is also characterized by an array of additional phenotypic affects which suggests a pivotal role for Ij in chloroplast development. The Ij gene from maize has been isolated; however, the sequence has not provided information on the action of the Ij gene product. As an extension of the analysis of the Ij gene we have generated a number of independent transposon insertion mutations using the Robertson's Mutator (Mu). Insertions were found to be distributed throughout the 5' half of the gene and all showed a similar striping pattern to that of the original ij mutation, ij-ref. While several of the new mutant alleles produced ij-homologous transcripts none produced detectable levels of the Ij polypeptide product. Chloroplast development in some cells appears to be able to proceed in the absence of the Ij polypeptide.

Alleles↗
PubMed1996

Pregnancy, alcohol use and the effectiveness of written health education materials.

This study was conducted to determine whether health education materials were more effective when written at a lower rather than a higher reading level. Women (n = 252) who visited public health maternity clinics selected either English- or Spanish-language health designed to discourage alcohol use, depending on whether the women preferred to read English or Spanish. The materials were written on the third and the 10th-grade reading levels. The women were randomly assigned to receive materials written on one of the two levels. Then participants completed the pre-test, read the health education material and were post-tested immediately. Among English-speaking participants, the material written at the lower reading level was shown to be more effective. Whereas among Spanish-speaking participants, test scores were unchanged after reading either health education material. Overall, we recommend that health care providers design or purchase materials that are easy-to-read and provide face-to-face counseling about abstaining from alcohol. Providers should not rely on written materials to communicate important messages when working with pregnant women.

Adult↗
PubMed1996

Non-phenolic linear diarylheptanoids from Curcuma xanthorrhiza: a novel type of topical anti-inflammatory agents: structure-activity relationship.

The topical anti-inflammatory activity of three non-phenolic linear 1,7-diarylheptanoids, previously isolated from a Thai medicinal plant, Curcuma xanthorrhiza (Zingiberaceae) and four new semi-synthetic derivatives of the naturally occurring compounds were assessed in the murine model of ethyl phenylpropiolate-induced ear edema. The naturally occurring compound 1E,3E,1,7-diphenylheptadien-5-one (6) exerted the most potent anti-inflammatory activity, with an ID50 value of similar magnitude to that of the reference drug oxyphenbutazone (67 vs. 46 micrograms/ear, respectively). None of the semi-synthetic diarylheptanoids was more active than 6. The chemical structures and pharmacological data of the natural and semi-synthetic derivatives identified a distinct structure-activity relationship. The degree of unsaturation in positions 1 and 3, and the nature of the oxygenated functional group in position 5 of the C7-chain were found to play significant roles in determining the observed in vivo activity. Based on these findings, the non-phenolic linear 1,7-diarylheptanoids-are proposed to represent a novel class of topical anti-inflammatory agents.

Alkynes↗