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Biomedical subjects

D S Gray

Publications and source records attributed to D S Gray.

At least 37 records · Page 2Linked to original sources
PubMed1989

Effect of carbohydrate refeeding on free fatty acids after a fast in obese diabetic and obese non-diabetic females.

The metabolic effects of refeeding with oral or intravenous carbohydrate were studied in obese women after ten or 14 days of fasting. Seven patients were refed with protein-free fruit juice for a total of 250 g of carbohydrate (1,000 kcal) over ten hours. The juice was sipped continuously throughout this time, causing a drop in free fatty acids (FFA) from 1.07 +/- 0.08 to 0.61 +/- 0.05 mmol/L (P less than .01) over the first four hours. Over the next four hours, despite continuous ingestion of the carbohydrate and elevated plasma glucose (132 +/- 9 mg/dL) and insulin (2.81 +/- 0.86 ng/mL) (1 ng/mL = 25 microU/mL), FFA rose to 0.99 mmol/L (P less than .01). Similar results were obtained in five patients refed with similar amounts of oral glucose and four patients who received an equivalent amount of glucose intravenously (IV). Refeeding with carbohydrate of obese diabetic and non-diabetic women after a two-week fast caused an abrupt decrease in FFA that was followed after four hours by an increase in FFA and glycerol, despite continued ingestion of carbohydrate glucose and insulin.

3-Hydroxybutyric Acid↗
PubMed1989

Diagnosis and prevalence of obesity.

Obesity is a condition of increased adipose tissue mass. Many techniques are available for measurement of body fat, but none is available widely for clinical purposes. The new technique of bioelectrical impedance may change this in the future. For now, relative weight and BMI are used as indices of obesity, which may be defined as a BMI greater than 30 kg per m2. This corresponds to a relative weight approximately 120 per cent above desirable. According to this definition, obesity exists in 10 to 12 per cent of adult men and women in the United States and Canada.

Adipose Tissue↗
PubMed1989

Effect of obesity on bioelectrical impedance.

The purpose of this study was to validate the use of bioelectrical impedance in assessing human body composition and to explore the use of this technique in obesity. Eighty-seven adults varying widely in body composition (range: 8.8-59.0% body fat) underwent measurement of bioelectrical impedance and underwater weighing (density). Fat-free mass determined from density (FFMd) was compared with FFM estimated from bioelectric impedance according to previously published regression equations. Correlation coefficients were high at all levels of body fat (0.94-0.99) but impedance equations overestimated FFM compared with FFMd in subjects greater than 42% body fat. This effect was greatest in subjects greater than 48% body fat and a regression equation was derived for determination of FFM for these subjects. These data confirm the excellent agreement between body composition determined from bioelectrical impedance and density but suggest that caution should be used in applying existing regression equations to very obese subjects.

Adult↗
PubMed1988

Effects of repeated weight loss and regain on body composition in obese rats.

To test the hypothesis that repeated loss and gain of weight through dieting will result in increasing fatness, 200-g female Sprague-Dawley rats were castrated and allowed to become obese on a high-fat diet for 6 wk. Two successive periods of severe food restriction (50% maintenance for 28 d and 25% maintenance for 21 d) were each followed by ad libitum refeeding on the high-fat diet until control body weights were attained. Percent body fat was determined indirectly from body density and total-body water at the end of each cycle. Restricted rats gained weight and attained control body weights on ad libitum feeding without overshooting these weights, and percentage body fat was not different from that of controls at the end of either cycle (cycle 1 22.3 +/- 1.7 vs 23.8 +/- 1.7%; cycle 2 19.0 +/- 1.1 vs 21.6 +/- 0.8%). Repeated cycles of weight loss and regain do not produce increased body fatness or decreased rate of weight loss in ovariectomized rats.

Animals↗
PubMed1988

Changes in bioelectrical impedance during fasting.

Six obese females had daily measurements of bioelectrical impedance during a 2-wk fast and measurement of total body water (TBW) by deuterium oxide dilution before and at the end of the fast. The three related measures of resistance (R), reactance (Xc), and impedance (Z) were found to follow very similar patterns throughout the fast, increasing for the first 7 d and remaining stable for the second 7 d. Weight loss averaged 10 kg and R increased whereas height squared divided by resistance (ht2/R) decreased during the fast with opposite changes during refeeding. Changes in resistance were significantly greater during the first week of fasting than during the second. With the exception of the subject who was the most obese, changes in ht2/R correlated well with changes in TBW (r = 0.94). It is concluded that bioelectrical impedance measurements accurately reflect changes in TBW during a 2-wk fast.

Adult↗
PubMed1988

Obesity. Part I--Pathogenesis.

Obesity--defined by a body mass index above 30 kg per m2--is a major problem for affluent nations. Its prevalence is higher in North America than in Europe--between 9% and 12% of the population. Reduced energy expenditure from exercise or metabolism or both may be an important contributory factor in the development of obesity because of a failure to reduce food intake sufficiently to maintain energy balance. A high ratio of abdominal circumference relative to gluteal circumference carries a twofold or greater risk of heart attack, stroke, hypertension, diabetes mellitus, gallbladder disease, and death. The effect of increased quantities of abdominal fat is greater than that of a similar increase in total body fat on the risks of ill health associated with obesity. Genetic factors appear to contribute about 25% to its etiology.

Adult↗
PubMed1988

Obesity. Part II--Treatment.

Conventional diets and increased exercise are the cornerstones of traditional therapy for obesity, but available data suggest that the most important component of any program is the associated behavior modification through which new ways of dealing with old problems can be learned and continually applied. This combined with very-low-calorie diets--less than 800 kcal per day--are in wide use, mostly under medical supervision. The currently available appetite-suppressing drugs are of limited efficacy, but many new ones are under active development and hold promise for the future. The most effective surgical intervention appears to be the gastric bypass operation, but this should be reserved for those who are at high risk from their obesity.

Female↗
PubMed1984

Short bowel syndrome.

This syndrome can result from surgical resection of large amounts of the small intestine. The hallmark is malabsorption, which can result in diarrhea, malnutrition, and a number of severe and possibly lethal metabolic abnormalities. New techniques for parenteral nutrition in the home have permitted patients with this syndrome to lead relatively normal lives, while allowing continuing adaptation of the remaining small intestine.

Adaptation, Physiological↗
PubMed1983

Nutritional support of the hospitalized patient.

Malnutrition is being recognized more frequently in hospitalized patients. Clinically significant malnutrition is defined as nutritional deficits that have serious adverse effects on the treatment and outcome of illness. The anergic metabolic profile is a simple method of assessing nutritional status. New techniques of enteral and parenteral nutritional support can stop or reverse the progression of malnutrition.

Adipose Tissue↗
PubMed1982

An inexpensive surgical headholder for the rat.

In many surgical procedures, there is a need to secure the animal's skull in a particular orientation. Described here is a surgical headholder for the rat that is inexpensive and easily constructed. The main component of the headholder is a screw type tubing clamp that is modified to allow the hard palate of the rat to be rigidly secured to the base plate of the clamp. This headholder has proven to be a highly satisfactory alternative to commercially available devices.

Animals↗
PubMed1979

An easily constructed durable chronic intracerebral cannula system.

A simple, inexpensive, and rugged intracerebral cannula system is described and construction details are provided for both guide and injection cannula assemblies. The guide cannula assembly is easily and quickly molded from dental acrylic cement and has a protective acrylic collar surrounding the end of the actual guide cannula. This system is believed to offer some advantage over current methodologies in terms of expense, durability and ease of construction and is well suited to use in rodents.

Animals↗