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Biomedical subjects

A Garg

Publications and source records attributed to A Garg.

At least 163 records · Page 9Linked to original sources
PubMed1992

Peculiar distribution of adipose tissue in patients with congenital generalized lipodystrophy.

Congenital generalized lipodystrophy (CGL) is a rare genetic disease with extreme paucity of fat from birth which is believed to be generalized, involving the whole body. Affected patients are characterized by severe insulin resistance. Sites of adipose tissue distribution in patients with CGL have not been studied systematically. Therefore, the fat distribution in three women (17-20 yr old) with CGL was investigated. Determination of body composition by underwater volume displacement suggested the complete absence of body fat (range, -3 to -7%; normal, 15-25%). Whole body magnetic resonance imaging, however, detected fat in particular anatomical sites, namely in orbits, palms and soles, and periarticular and epidural regions. Some fat was also localized in the tongue, breasts, vulva, and buccal area. Fat in other subcutaneous areas, intraabdominal and intrathoracic regions, and bone marrow was essentially absent. Thus, patients with CGL do not have a complete absence of body fat; of interest, fat is present in those sites where adipose tissue may be serving mainly a mechanical function. Patients with CGL, therefore, provided a unique opportunity to identify the various sites of localization of "mechanical" adipose tissue in the human body. Our study suggests that the genetic defect in CGL results in poor growth and development of metabolically active adipose tissue, whereas mechanical adipose tissue is well preserved.

Adipose Tissue↗
PubMed1992

Lipid-lowering therapy and macrovascular disease in diabetes mellitus.

Patients with diabetes mellitus are at increased risk of morbidity and mortality from macrovascular disease manifesting as coronary heart disease, cerebrovascular accidents, and peripheral vascular disease. Increased frequency of dyslipidemia, hyperglycemia, obesity, hypertension, and associated nephropathy may contribute to accelerated atherogenesis in diabetic patients. Therefore, besides intensive control of hyperglycemia, management of dyslipidemia, hypertension, and obesity should also be emphasized in diabetic patients. Those who smoke should be strongly encouraged to quit smoking. Besides attempts to achieve normal levels of plasma lipoproteins, consideration also should be given to normalization of compositional abnormalities of various lipoproteins in patients with diabetes mellitus. The therapeutic goals for cholesterol reduction should be lower in diabetic patients than nondiabetic subjects. The first step is to achieve good metabolic control of diabetes mellitus by diet, exercise, and weight reduction and, if needed, with sulfonylureas or insulin therapy. Because most of the patients with insulin-dependent diabetes mellitus achieve normal levels of plasma lipoproteins with intensive insulin therapy, lipid-lowering medications are rarely needed. In patients with non-insulin-dependent diabetes mellitus, however, dyslipidemia often persists despite good glycemic control. Lipid-lowering medications should be considered in such patients. Because nicotinic acid can cause marked deterioration in glycemic control, and bile acid-binding resins may accentuate hypertriglyceridemia, these agents are less desirable for use by diabetic patients. Inhibitors of hydroxymethylglutaryl coenzyme A reductase may be preferred in patients with elevated LDL cholesterol and mld hypertriglyceridemia. For diabetic patients with marked hypertriglyceridemia, however, fibric acid derivatives should be the drug of choice.

Diabetic Angiopathies↗
PubMed1992

Effect of high carbohydrate intake on hyperglycemia, islet function, and plasma lipoproteins in NIDDM.

OBJECTIVE: To study effects of high carbohydrate intake on hyperglycemia, islet functions, and plasma lipoproteins in patients with NIDDM. RESEARCH DESIGN AND METHODS: An attempt was made to induce hyperglycemia in 10 men with NIDDM by feeding them an isocaloric high-carbohydrate diet (65% of energy as simple carbohydrates [31% as glucose] and 20% as fat) for 28 days in a metabolic ward. Response to the high-carbohydrate diet was compared with that of feeding a diet rich in monounsaturated fat (45% of energy as fat [31% as monounsaturated fat] and 38% as carbohydrates) for 28 days in a cross-over manner. Islet functions were assessed by evaluating plasma glucose, insulin, C-peptide and glucagon responses to standard meal tolerance tests on days 0, 14, 21, and 28 of each dietary period. Fasting plasma lipoproteins were determined during the last week of each dietary period. RESULTS: The high-carbohydrate diet caused significant but modest accentuation of hyperglycemia, particularly in patients with moderately severe diabetes mellitus, whereas no change was observed with the high-monounsaturated fatty-acid diet. Accentuation of hyperglycemia was accompanied by an increase in plasma glucagon levels, but no significant change in insulin and C-peptide responses. In 1 patient, feeding the high-carbohydrate diet for 68 days produced marked hyperglycemia and caused definite suppression of insulin and C-peptide responses along with an increase in glucagon levels. Compared with the high-monounsaturated fat diet, the high-carbohydrate diet also raised plasma triglyceride and VLDL cholesterol concentrations. CONCLUSIONS: High-carbohydrate diets may cause accentuation of hyperglycemia and a rise in plasma glucagon levels in NIDDM patients. High-carbohydrate diets also adversely affect lipoproteins and therefore may not be desirable in all NIDDM patients.

Blood Glucose↗
PubMed1992

High-carbohydrate, low-fat diet? Negative.

Triglyceride levels rise with increased carbohydrate intake, according to a long-term study of normal children from several countries. Moreover, carbohydrate raises blood glucose levels and insulin requirements.

Cholesterol↗
PubMed1992

Comparison of effects of high and low carbohydrate diets on plasma lipoproteins and insulin sensitivity in patients with mild NIDDM.

Previous studies indicate that diets rich in digestible carbohydrates improve glucose tolerance in nondiabetic individuals, but may worsen glycemic control in NIDDM patients with moderately severe hyperglycemia. The effects of such high-carbohydrate diets on glucose metabolism in patients with mild NIDDM have not been studied adequately. This study compares responses to an isocaloric high-carbohydrate diet (60% of total energy from carbohydrates) and a low-carbohydrate diet (35% of total energy from carbohydrates) in 8 men with mild NIDDM. Both diets were low in saturated fatty acids, whereas the low-carbohydrate diet was rich in monounsaturated fatty acids. The two diets were matched for dietary fiber content (25 g/day). All patients were randomly assigned to receive first one and then the other diet, each for a period of 21 days, in a metabolic ward. Compared with the low-carbohydrate diet, the high-carbohydrate diet caused a 27.5% increase in plasma triglycerides and a similar increase in VLDL-cholesterol levels; it also reduced levels of HDL cholesterol by 11%. Plasma glucose and insulin responses to identical standard breakfast meals were studied on days 4 and 21 of each period, and these did not differ significantly between the two diets. At the end of each period, a euglycemic hyperinsulinemic glucose clamp study with simultaneous infusion of [3-3H]glucose revealed no significant changes in hepatic insulin sensitivity; and peripheral insulin-mediated glucose disposal remained unchanged (14.7 +/- 1.4 vs. 16.5 +/- 2.3 microM.kg-1.min-1 on the high-carbohydrate and low-carbohydrate diets, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1992

A truncated species of apolipoprotein B, B-83, associated with hypobetalipoproteinemia.

Familial hypobetalipoproteinemia, a syndrome associated with low plasma cholesterol levels, can be caused by apoB gene mutations. We identified a healthy 42-year-old man whose total plasma cholesterol level was 80 mg/dl. His plasma very low density lipoprotein (VLDL) contained a unique truncated apoB species, apoB-83, in addition to the normal B apolipoproteins, apoB-100 and apoB-48. Virtually no apoB-83 was detectable in his low density lipoprotein (LDL). From the subject's kindred, we identified nine other hypocholesterolemic subjects whose VLDL contained apoB-83. A tendency for cholelithiasis was noted in the apoB-83 heterozygotes, particularly in the older individuals. From the apparent size of apoB-83 on SDS-polyacrylamide gels and its reactivity with apoB-specific monoclonal antibodies, we estimated that it would contain approximately 3700-3800 amino acids. DNA sequencing of apoB genomic clones from two affected individuals revealed that apoB-83 was caused by a C----A transversion in exon 26 of the apoB gene (apoB cDNA nucleotide 11458). This mutation converts Ser-3750 (TCA) into a premature stop codon (TAA) and creates a unique MseI restriction endonuclease site. Thus, a single nucleotide transversion in the apoB gene results in a unique truncated apoB species, apoB-83, and the clinical syndrome of familial hypobetalipoproteinemia.

Adolescent↗
PubMed1991

DNA adducts of the antitumor agent diaziquone.

We have studied adduct formation of the antineoplastic agent diaziquone (AZQ; NSC 182986) with DNA and nucleotides in vitro. The aziridine moieties of AZQ can be expected to interact covalently with DNA which, in turn, presumably elicits the antitumor activity. We analyzed AZQ-DNA adducts by a modified 32P-postlabeling assay involving purification of the nuclease P1-enriched labeled adducts by high-salt C18 reversed-phase thin-layer chromatography and separation of the eluted adducts on a polyethyleneimine-cellulose layer using non-urea salt solutions. Modification of calf thymus DNA with AZQ produced two major (22% and 40%) and at least eight minor adducts. At equal concentrations of AZQ and DNA (1 micrograms/microliters each), peak binding was observed in about 2 h [1926 +/- 378 (SD) fmol/micrograms of DNA] with the binding levels remaining practically unchanged through 4 h. However, incubation for 24 h resulted in over 40% decline, indicating adduct instability. AZQ was found to be highly reactive in vitro as evidenced by its substantial binding (49 +/- 14 fmol/micrograms of DNA) even at a DNA:AZQ ratio of 100:1. When incubated with mononucleotides, AZQ reacted extensively with adenine, guanine, and cytosine but only slightly with thymine. Cochromatography of the modified DNA and nucleotides revealed that one of the major adducts and several minor adducts were guanine derived. The aziridine rings of AZQ were found to be the main reactive sites as its monoaminoalcohol derivative showed as much DNA reactivity as did the parent compound, but no activity was observed when both aziridine groups were hydrolyzed to diaminoalcohols. The improved 32P-postlabeling assay seems capable of detecting relatively polar adducts such as those formed with AZQ at a level of one adduct/10(9) nucleotides.

Animals↗
PubMed1991

The potential of carp to bioactivate benzo[a]pyrene to metabolites that bind to DNA.

We have investigated the formation of DNA adducts in starved, fed and 5,6-benzoflavone-pretreated carp following i.p. administration of benzo(a)pyrene. 32P-postlabeling analysis of the liver DNAs showed the presence of one predominant (greater than 92%) adduct in all three groups. Cochromatography experiments revealed that the main adduct was identical to authentic BPDEI-dG (10 beta-(deoxyguanosin-N2-yl)-7 beta, 8 alpha, 9 alpha-trihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene). The formation of the adduct was evident as early as 1.5 h post-treatment and the levels increased steadily up to 7 days, reaching about 125, 110 and 102 attomole/microgram DNA in starved, fed and benzoflavone-pretreated carp, respectively. During this period, the benzo[a]pyrene-induced benzo[a]-pyrene monooxygenase activity increased from the uninduced, natural level of about 3 pmol/mg per min to levels of 35, 62 and 79 pmol/mg per min in starving, fed and 5,6-benzoflavone pretreated fish, respectively. A slow but steady formation of the diolepoxide-dG adduct was also observed in the liver DNA of carp following p.o. treatment. These results indicate that carp can biotransform polycyclic aromatic hydrocarbons such as benzo[a]pyrene to 'reactive' metabolites that bind to DNA.

Animals↗
PubMed1991

Contralateral pneumonectomy after single-lung transplantation for emphysema.

An intractable contralateral air leak developed in a 46-year-old woman after right single-lung transplantation for emphysema. A left pneumonectomy was performed on postoperative day 17, leaving the patient with only one transplanted lung. Fifteen months postoperatively the patient is well and has satisfactory pulmonary function. Survival with a good quality of life is possible after single-lung transplantation and bilateral sequential pneumonectomies.

Female↗
PubMed1991

A biomechanical and ergonomic evaluation of patient transferring tasks: bed to wheelchair and wheelchair to bed.

A laboratory study was conducted in an effort to reduce back stress for nursing personnel while performing the patient handling tasks of transferring the patient from bed to wheelchair and wheelchair to bed. These patient handling tasks were studied using five manual techniques and three hoist-assisted techniques. The manual techniques involved one-person and two-person transfers. One manual technique involved a two-person lift of the patient under the arms; the others used a rocking and pulling action and included the use of assistive devices (a gait belt using a two-person transfer, a walking belt with handles using a one-person and a two-person transfer, and a patient handling sling with cutout areas to allow for a hand grip (Medesign) for a one-person transfer). The three mechanical hoists were Hoyer, Trans-Aid and Ambulift. Six female nursing students with prior patient transfer experience served both as nurses and as passive patients. Static biomechanical evaluation showed that pulling techniques, as compared to lifting the patient, required significantly lower hand forces and produced significantly lower erector spinae and compressive forces at the L5/S1 disc (P greater than or equal to 0.01). Shear force, trunk moments and the percentage of females who were capable of performing the transfers (based on static strength simulation) also favoured pulling methods. Perceived stress ratings for the shoulder, upper back, lower back and whole body were lower for pulling methods than those for lifting the patient (P less than or equal to 0.01). Patients found the pulling techniques, with the exception of when using the gait belt, felt more comfortable and more secure than the lifting method (P less than or equal to 0.01). However, a number of subjects believed that the patient handling sling (Medesign) and the walking belt with one person making the transfer would not work for those patients who could not bear weight and those who were heavy, contracted or combative. A walking belt with two persons was the preferred manual method. Two out of three hoists (Hoyer lift and Trans-Aid) were perceived by the nurses to be as physically stressful as manual methods. Patients found these two hoists to be more uncomfortable and felt less secure than with three of the five manual methods (one- and two-person walking belts and Medesign). Ambulift was found to be the least stressful, the most comfortable, and the most secure among all eight methods. Pulling techniques and hoists took significantly longer amounts of time to make the transfer than manually lifting the patient (P less than or equal to 0.01). The two-person walking belt using a pulling technique and Ambulift are recommended for transferring patients from bed to wheelchair and wheelchair to bed. A large-scale field study is needed to verify these recommendations.

Adult↗
PubMed1991

A biomechanical and ergonomic evaluation of patient transferring tasks: wheelchair to shower chair and shower chair to wheelchair.

A laboratory study was conducted to evaluate five different manual techniques (two-person manual lifting; rocking and pulling the patient using a gait belt with two persons; walking belt with one and two persons) and three different mechanical hoists (Hoyer lift, Trans-Aid and Ambulift) for transferring patients from wheelchair to shower chair and shower chair to wheelchair. Six female nursing students with prior patient transfer experience served both as nurses and as passive patients. Static biomechanical evaluation showed that the mean trunk flexion moments, erector spinae muscle forces and compressive and shear forces at the L5S1 disc for the four pulling methods ranged from 92 to 125 Nm, 1845 to 2507 N, 1973 to 2641 N and 442 to 580 N, respectively, as compared to about 213 Nm, 4260 N, 5050 N and 926 N for two-person manual lifting. Perceived stress ratings for the shoulder, upper back, lower back and whole body were significantly lower for pulling methods than those for lifting the patient (p less than or equal to 0.01). Patients found pulling techniques, except the gait belt, to be more comfortable and secure than the lifting method (p less than or equal to 0.01). However, most of the nurses believed that Medesign and the one-person walking belt would not work on those patients who cannot bear weight and those who are heavy, contracted or combative. A two-person walking belt was the most preferred method. Two out of three hoists (Hoyer lift and Trans-Aid) were perceived by the nurses to be more stressful than one- and two-person walking belts. The patients found these two hoists to be more uncomfortable and less secure than with three of the five manual methods (one- and two-person walking belts and Medesign). Pulling techniques and hoists took significantly longer amounts of time to make the transfer than manually lifting the patient (p less than or equal to 0.01). The two-person walking belt, using a gentle rocking motion to utilize momentum and a pulling technique, and Ambulift are recommended for transferring patients from wheelchair to shower chair and shower chair to wheelchair.

Baths↗
PubMed1991

Ergonomics and the older worker: an overview.

Several studies have shown that an individual's capacity for physical and mental work tends to decrease with advancing age. Different capacities begin to deteriorate at different ages and at different rates. However, important bench marks appear to occur in the twenties, forties, and sixties. Ergonomics is the science of fitting the task to the worker. It offers the potential of compensating for the decrease in an individual's functional capacities that occur with age through appropriate job design. Without proper ergonomic job design, older workers could well find themselves at a disadvantage due to compromised productivity and health. This overview will cover the history of ergonomics and its importance in workplace design. The effects of age-related declines on various physical and mental capacities will be reviewed and ergonomic recommendations to accommodate these declines will be presented. To remain competitive in an international marketplace the skills and knowledge of the older worker must be used advantageously. The knowledge required to keep the older worker employed safely and productively can only be acquired through a carefully designed longitudinal study patterned after the Baltimore Longitudinal Study.

Accidents, Occupational↗
PubMed1991

Postheparin lipolytic activity and plasma lipoprotein response to omega-3 polyunsaturated fatty acids in patients with primary hypertriglyceridemia.

The hypotriglyceridemic action of omega-3 (n-3) fatty acids is attributed primarily to reduction in hepatic triglyceride synthesis and reduced secretion of very-low-density lipoproteins (VLDLs). However, increased catabolism of triglyceride-rich lipoproteins was reported and could be due to increased availability of peripheral lipoprotein lipase (LPL) or hepatic lipase (HL). In this study plasma lipoproteins and postheparin activities of LPL and HL were determined in 12 patients with primary hypertriglyceridemia before and during isocaloric substitution of omega-3 fatty acids (10 g/d) for 4 wk. Omega-3 polyunsaturates resulted in 53% and 61% reductions in plasma triglyceride and VLDL-cholesterol concentrations, respectively (P less than 0.0001). However, low-density-lipoprotein (LDL)-cholesterol concentrations increased by 26% (P less than 0.001). Activities of postheparin LPL and HL essentially remained the same. Thus, in patients with primary hypertriglyceridemia, reduction in plasma triglyceride concentrations and increase in LDL-cholesterol concentrations mediated by omega-3 polyunsaturates seem to occur without an increase in LPL or HL activities.

Aged↗
PubMed1991

Effects of cooling the legs on performance in a standard Wingate anaerobic power test.

The possibility that peripheral hypothermia may impair muscular performance in various sports led us to assess the usefulness of the Wingate anaerobic power test in subjects with normal and cooled leg muscles. Using this test without modification, peak power, average power output, and cumulated work to the point of fatigue were all decreased by cooling, although the fatigue index (the declining rate of change of power output) was less. It is concluded that this test could usefully be employed in field studies to assess the possibility that muscle chilling may influence a person's potential for producing maximal bursts of muscular work.

Adult↗