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Biomedical subjects

G D Foster

Publications and source records attributed to G D Foster.

At least 37 records · Page 2Linked to original sources
PubMed2000

The cylindrical inclusion gene of Turnip mosaic virus encodes a pathogenic determinant to the Brassica resistance gene TuRB01.

The viral component of Turnip mosaic virus (TuMV) determining virulence to the Brassica napus TuRB01 dominant resistance allele has been identified. Sequence comparisons of an infectious cDNA clone of the UK 1 isolate of TuMV (avirulent on TuRB01) and a spontaneous mutant capable of infecting plants possessing TuRB01 suggested that a single nucleotide change in the cylindrical inclusion (CI) protein coding region (gene) of the virus was responsible for the altered phenotype. A second spontaneous mutation involved a different change in the CI gene. The construction of chimeric genomes and subsequent inoculations to plant lines segregating for TuRB01 confirmed the involvement of the CI gene in this interaction. Site-directed mutagenesis of the viral coat protein (CP) gene at the ninth nucleotide was carried out to investigate its interaction with TuRB01. The identity of this nucleotide in the CP gene did not affect the outcome of the viral infection. Both mutations identified in the CI gene caused amino acid changes in the C terminal third of the protein, outside any of the conserved sequences reported to be associated with helicase or cell-to-cell transport activities. This is the first example of a potyvirus CI gene acting as a determinant for a genotype-specific resistance interaction.

Brassica↗
PubMed1999

Two-year changes in lipids and lipoproteins associated with the maintenance of a 5% to 10% reduction in initial weight: some findings and some questions.

OBJECTIVE: This study assessed whether a 5% to 10% reduction in initial weight would be associated with as favorable long-term (i.e., 100 weeks) changes in lipids and lipoproteins, as have been observed on a short-term basis (i.e., 8 weeks). RESEARCH METHODS AND PROCEDURES: This was a prospective evaluation of 25 obese women, each of whom had lost > or =5% of initial weight during 48 weeks of treatment and had maintained a weight loss of this magnitude at 1-year follow-up (week 100). Lipids and lipoproteins were obtained at baseline and at weeks 8, 24, 48, and 100. All participants had a baseline total cholesterol > or =5.17 mmol/L (200 mg/dL). RESULTS: At the end of the first 8 weeks, weight fell an average of 11.7+/-2.8%, total cholesterol 20.6+/-7.5%, low-density-lipoprotein (LDL) cholesterol 23.0+/-18.1%, and triglycerides 26.0+/-20.1%. At week 48, weight had fallen to 20.1+/-7.0% below baseline, but total cholesterol and LDL cholesterol were reduced only 11.5+/-10.4% and 12.0+/-14.0% below baseline, respectively. These latter reductions were significantly (p<0.05) smaller than those observed at week 8, despite the larger weight loss at week 48. High-density-lipoprotein cholesterol declined significantly (p<0.05) during the first 8 weeks, but returned to baseline values by week 24. Patients gained 7.4+/-7.4 kg from weeks 48 to 100, during which time total and LDL cholesterol (but not triglycerides) rose significantly (p<0.05). Patients who, at week 100, maintained losses >10% of initial weight had significantly greater reductions in total and LDL cholesterol values than did patients who maintained losses of only 5% to 10% of initial weight. DISCUSSION: Results of this study underscore the importance of assessing long-term changes in weight-related health complications when patients have lost weight but are no longer dieting (and exercising) as aggressively as they did during the initial months of treatment.

Adult↗
PubMed1999

Analysis of a translational enhancer present within the 5'-terminal sequence of the genomic RNA of potato virus S.

When present as a transcript leader the 5' untranslated sequence from the potato virus S genomic RNA molecule enhances translation of a downstream open reading frame both in vitro and in vivo. Translational enhancement was 30-fold in rabbit reticulocyte lysate and 15 fold in wheat germ above translation from a transcript with a synthetic leader. Transient expression experiments using tobacco protoplasts and particle bombardment of leaf tissue resulted in enhancement of fourteen and five-fold, respectively, above translation with a synthetic leader. In stably transformed plants the PVS 5'UTR enhanced translation yield ca. 5-fold compared with a synthetic 5'UTR.

5' Untranslated Regions↗
PubMed1999

Changes in resting energy expenditure after weight loss in obese African American and white women.

BACKGROUND: Previous studies showed that resting energy expenditure (REE) is lower in obese African American women than in obese white women. It is unknown, however, whether there are racial differences in how REE responds to weight loss and energy restriction. OBJECTIVE: We assessed REE, body composition, and respiratory quotient before and after weight loss in obese black and white women. DESIGN: We measured REE by indirect calorimetry and body composition by densitometry before and after 20-24 wk of treatment with a 3870-4289-kJ/d diet. Subjects were 109 obese females (24 black, 85 white) with a mean (+/-SD) body mass index (in kg/m2) of 36.3+/-5.0, weight of 95.7+/-12.6 kg, and age of 42.3+/-8.1 y. RESULTS: Before treatment, REE, adjusted for body composition, was significantly lower in black than in white subjects (P = 0.001). Black subjects lost significantly less weight during treatment than did white subjects (13.4+/-5.9 kg or 14.2+/-5.7% compared with 16.4+/-5.6 kg or 17.0+/-5.7%, respectively; P = 0.04). Analyses that controlled for initial REE and changes in fat mass and fat-free mass showed that blacks had significantly greater decreases in REE after treatment than did whites (9.9+/-7.3% compared with 6.3+/-7.4%; P = 0.02). CONCLUSION: This study suggests that weight loss results in greater reductions in REE in obese black women than in obese white women. These data underscore the need to consider both biological and behavioral factors when setting expectations and assessing outcomes for obesity treatment in African American women.

Adult↗
PubMed1998

A comparison of two approaches to the assessment of binge eating in obesity.

OBJECTIVE: To compare two different methods of assessing binge eating in a sample of 128 obese women enrolled in a weight loss protocol. METHOD: Prior to treatment, participants completed the Binge Eating Scale (BES) and the Questionnaire on Eating and Weight Patterns (QEWP), as well as measures of other relevant constructs. They were then classified as bingers and nonbingers by each method and chance-corrected agreement was calculated. RESULTS: The BES and QEWP identified a small and nearly equal number of subjects as having significant binge eating, but there was only modest overlap between the two groups (kappa of .45). Subgroup comparisons revealed fundamental differences between the BES and QEWP in the assessment of the critical and associated features of binge eating. DISCUSSION: The relative merits of these two approaches to classifying binge eaters and implications for the design of new methods are discussed.

Adult↗
PubMed1998

The fen-phen finale: a study of weight loss and valvular heart disease.

OBJECTIVE: To assess weight loss, as well as the prevalence of valvular heart disease, in 21 obese women who completed 2 years of treatment by fenfluramine and phentermine (fen-phen) in June 1997. RESEARCH METHODS AND PROCEDURES: Patients were 21 of 22 women who had completed a 1-year, open-label trial of fen-phen combined with lifestyle modification. This study describes the results of a second year of treatment. The presence of valvular heart disease, defined as aortic regurgitation of mild or greater severity and/or mitral regurgitation of moderate or greater severity, was assessed using two-dimensional, color Doppler and pulsed- and continuous-wave Doppler examinations. RESULTS: At 2 years, the 21 patients had a mean reduction in initial weight of 13.9 + 10.0%, which was significantly (p<0.001) smaller than their 1-year loss of 17.1 +/- 8.7%. Nine of 21 patients reported that they took fen-phen irregularly during the last 4 months of the study because of fears of developing health complications. These nine patients had a 2-year weight loss of 8.7 +/- 7.5%, compared with a significantly (p<0.04) larger loss of 17.6 +/- 10.5% for participants who reported taking medication regularly. Six of 20 (30%) patients met criteria for valvular heart disease. None of the six had signs or symptoms of this condition. DISCUSSION: Fenfluramine was withdrawn from the market on September 15, 1997 because of concerns that it was associated with valvular heart disease. The present findings are discussed in terms of the potentially favorable long-term benefits of combining lifestyle modification with weight loss medications that are both safe and effective.

Adult↗
PubMed1998

RNA extraction from virus-diseased sweet potato for reverse transcriptase polymerase chain reaction analysis.

Sweet potato virus disease (SPVD), which causes severe crop losses in Africa, is caused by a complex of sweet potato feathery mottle potyvirus (SPFMV) and sweet potato chlorotic stunt crinivirus (SPCSV). Extraction of pure RNA (for diagnosis by reverse transcriptase polymerase chain reaction [RT-PCR] methods) from diseased sweet potato proved to be difficult using five different total-RNA extraction procedures: (a) that of Chomczynski and Sacchi (1) (b) an adaptation of Lodhi et al., (2) and three commercially available kits (c) Clonsep (Clontech, Clontech Labs Inc, Palo Alto, CA; (d) RNeasy (Qiagen, West Sussex, UK); and (e) RNA isolator (Genosys Biotechnologies). Four of these methods (b-e) generated sufficient RNA, but it was unsuitable for RT-PCR amplification of SPFMV. When these RNA samples were treated with Wizard DNA extraction resin (Promega), the inhibitors of RT-PCR were consistently removed from three (b-d) of these four samples. Another deproteinating step was needed to allow RT-PCR amplification of sample e. The Wizard DNA column purification in conjunction with one of these total RNA extraction methods facilitates quick and reliable extraction of pure RNA for diagnostic purposes and might be suitable for similar problematic plant material.

Plant Diseases↗
PubMed1998

Exercise and the maintenance of weight loss: 1-year follow-up of a controlled clinical trial.

This study reports results 1 year after treatment for 77 obese women who had been treated for 48 weeks by diet combined with supervised (a) aerobic exercise, (b) strength training, (c) aerobic plus strength training combined, or (d) no exercise. Mean (+/- SD) end-of-treatment weight losses for the 4 conditions ranged from 13.5 +/- 9.1 kg to 17.3 +/- 10.3 kg, but there were no statistically significant differences among groups. Participants in all 4 conditions regained approximately 35% to 55% of their weight loss in the year after treatment; again, there were no significant differences among groups. Participants, however, who reported exercising regularly in the 4 months preceding the follow-up assessment regained significantly less weight than did nonexercisers.

Adult↗
PubMed1998

Assessment of body image dissatisfaction in obese women: specificity, severity, and clinical significance.

This study assessed the specificity, severity, and clinical significance of body image dissatisfaction in 79 obese women using the Body Dysmorphic Disorder Examination--Self-Report (J. C. Rosen & J. Reiter, 1996). The vast majority of obese women demonstrated body image dissatisfaction related to their obesity, with almost half reporting the greatest dissatisfaction with their waist or abdomen. On average, they reported significantly more body image dissatisfaction than did 43 nonobese controls. The 2 groups did not differ on self-reported symptoms of depression or self-esteem. Body image dissatisfaction correlated significantly with reports of depressive symptoms and lower self-esteem but was not correlated with body mass index. Results are discussed in terms of the role of body image dissatisfaction in understanding and treating obese individuals.

Adult↗
PubMed1998

The Eating Inventory in obese women: clinical correlates and relationship to weight loss.

OBJECTIVES: Describe the physical and psychological correlates of the Eating Inventory (EI) (also known as the Three-Factor Eating Questionnaire) factors in an obese sample, and determine the relationship between the three EI factors and weight loss. DESIGN: Consecutive series of obese women enrolled between 1987 and 1996 in clinical trials of weight loss treatments. PARTICIPANTS: 223 obese women with a weight of 100.7 +/- 15.5 kg, an age of 41.4 +/- 8.8 y and a body mass index (BMI) of 37.2 +/- 5.6 kg/m2. MEASURES: The EI and a variety of physical (weight, body composition and resting energy expenditure) and psychological (mood and binge eating) measures were assessed before and after 5-6 months of treatment. RESULTS: Before treatment, higher restraint scores were associated with lower body weights (P = 0.02), while higher disinhibition scores were associated with greater binge eating severity (P<0.0001). Weight loss treatment was associated with significant increases in restraint and decreases in disinhibition and hunger (all Ps<0.0001). Greater increases in restraint during treatment were associated with larger weight losses (P<0.0001). CONCLUSIONS: The three factors of the EI showed clinical utility in a sample of women receiving treatment for obesity.

Adult↗
PubMed1998

Short- and long-term changes in serum leptin dieting obese women: effects of caloric restriction and weight loss.

This study examined the effects of caloric restriction and weight loss on serum leptin concentrations in 49 obese women who participated in a 40-week weight loss program. During the first 12 weeks, half the subjects were provided a 1000 kcal/day low-calorie diet (LCD), compromised of portion-controlled foods, whereas the other half were prescribed a 1200 kcal/day balanced deficit diet (BDD) consisting of self-selected table foods. Thereafter, subjects in both conditions were instructed to consume approximately 1200-1800 kcal/day of self-selected foods, depending on their desired weight change. During the first 6 weeks, weight and serum leptin fell significantly more (P < 0.05) in women in the LCD condition than in the BDD condition. In the former group, the 55% reduction in baseline leptin was 10 times greater than the relative reduction in body weight. Stepwise multiple regression analysis revealed that degree of caloric restriction, but not weight loss, contribution significantly to the variance in the change in leptin at week 6. By contrast, long-term changes in leptin, when subjects had increased their calorie intake, were more strongly related to changes in weight and fat. At week 40, for example, weight loss account for 47% of the variance in the change in leptin. Serum leptin and body fat remained highly correlated after weight loss (r = 0.79, P < 0.001), as before (r = 0.66, P < 0.001). After treatment, however, we observed a greater-than-expected reduction in serum leptin concentrations, as expressed per kilogram of body fat. The significance of this finding remains to be determined.

Adipose Tissue↗
PubMed1997

Resting energy expenditure in obese African American and Caucasian women.

The prevalence of obesity among African American women approaches 50% and greatly exceeds rates for Caucasian women. In addition, black women lose less weight than white during obesity treatment and gain more weight when untreated. This study assessed resting energy expenditure (REE) and body composition in obese white (n = 122) and black (n = 44) women to explore the relationship between biological variables and these observed differences. REE and body composition were assessed by indirect calorimetry and densitometry, respectively, before weight loss. REE was significantly lower in black subjects (1637.6 +/- 236.9 kcal/d) than in white (1731.4 +/- 262.0) (p = 0.04). REE remained significantly lower in blacks than whites after adjusting for body weight (p = 0.02). REE, adjusted for fat-free mass, was also significantly lower in blacks than whites (p < 0.0001), although the overestimation of fat-free mass by densitometry in blacks may have contributed to this finding. There were no differences between the groups in respiratory quotient. These results suggest that a decreased REE may exist in obese black women, and it may be related to the observed differences between black and white women in the prevalence of obesity and in the response to weight loss treatment. These cross-sectional findings await confirmation in longitudinal studies.

Adult↗
PubMed1997

Lifestyle modification in the pharmacologic treatment of obesity: a pilot investigation of a potential primary care approach.

This study examined a new method of providing brief, individual lifestyle modification to obese individuals treated by pharmacotherapy. Twenty-six women with a mean (+/- SD) age of 47.0 +/- 7.2 years, weight of 97.6 +/- 13.0 kg, and body mass index of 36.5 +/- 5.0 kg/m2 were prescribed 60 mg/d of fenfluramine and 15 mg/d of phentermine for one year. In addition, half of the women were randomly assigned to traditional group behavior modification, conducted by a nutritionist, which included 32 75-minute sessions during the year. The other half were provided lifestyle modification by a physician during 10 15-20 minute structured visits. All participants received identical treatment manuals and comparable assignments for behavior change. At the end of one year, patients in the physician group achieved the same highly successful weight losses as those treated by group behavior modification (13.9 +/- 9.6 kg vs. 15.4 +/- 7.9 kg, respectively). Treatment was associated with highly significant improvements in lipids and lipoproteins, as well as in mood and several measures of appetite. Weight loss the first four weeks, as well as patient completion of daily food records during the first 18 weeks, correlated positively with weight loss at weeks 18, 26, and 52. Results of this study await replication using larger samples but strongly suggest that effective lifestyle modification can be provided during brief, structured physician visits. The findings are discussed in terms of their implications for the treatment of obesity in primary care practice.

Adult↗
PubMed1997

Psychological effects of weight cycling in obese persons: a review and research agenda.

This review summarizes studies on the psychological effects of weight cycling (i.e., weight loss and regain) in obese persons and proposes an agenda for future research on this topic. Among general psychological constructs, the current literature suggests that weight cycling is not associated with depression, other psychopathology, or depressogenic cognitive styles. Weight cycling is associated with decreased perceptions of health and well-being, although the clinical significance of this relationship is uncertain. Among weight- and eating-related constructs, weight cycling does not appear to be related to restraint, hunger, or personality traits associated with eating disorders. Weight cycling, however, does appear to be associated with clinically significant reductions in eating self-efficacy and weak but consistent increases in binge eating severity. Definitive conclusions about the presence or absence of the psychological consequences of weight cycling are premature, given the small number of studies, as well as a variety of methodological and interpretive concerns. A new generation of research is necessary to determine the extent and nature of the psychological sequelae of weight cycling.

Eating↗