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Biomedical subjects

T L Roberts

Publications and source records attributed to T L Roberts.

17 recordsLinked to original sources
PubMed1995

trans isomers of oleic and linoleic acids in adipose tissue and sudden cardiac death.

trans isomers of unsaturated fatty acids are formed by biological or industrial hydrogenation. A population case-control study of sudden cardiac death in mean was done to test the hypothesis that trans isomers of oleic acid and linoleic acid increase the risk of sudden cardiac death due to coronary artery disease. In adipose tissue obtained at necropsy from 66 cases of sudden cardiac death and taken from 286 healthy age and sex matched controls, the proportions of trans isomers of oleic and linoleic acid were measured by gas-liquid chromatography. In cases, the mean (SE) percentage of total trans fatty acids (C18:1 plus C18:2), expressed as a proportion of all fatty acids, was significantly lower (2.68 [0.08]%) than in healthy controls (2.86 [0.04]%; p < 0.05). trans C18:1 was 2.1 (0.7)% in cases compared with 2.27 (0.04)% (p < 0.05) in controls. The proportion of all trans isomers of linoleic acid was 0.58 (0.02)% in cases compared with 0.59 (0.01)% in controls (p = 0.98). The estimated relative risk for sudden cardiac death of trans C18:1 and C18:2 fatty acids combined did not differ significantly from 1.0 in relation to the distribution of these trans isomers by quintile in the control population. The relative risk (95% CI) of sudden cardiac death in the top quintile was 0.40 (0.15-1.02) for C18:1 and 1.08 (0.48-2.74) for C18:2 compared with the bottom quintiles of their respective control distributions. When these univariate relations for trans fatty acids were adjusted for coronary risk factors, smoking was the only factor that remained independently associated with risk of sudden cardiac death (2.27 [1.23-4.17]). Overall, there was no evidence of a relation between trans isomers of oleic and linoleic acids combined and sudden cardiac death. However, trans oleic acid was negatively associated with risk of sudden cardiac death, whereas no association with trans forms of linoleic acid was seen. This study does not support the hypothesis that trans isomers increase the risk of sudden cardiac death.

Adipose Tissue↗
PubMed1993

Linoleic acid and risk of sudden cardiac death.

OBJECTIVE: To test the hypothesis that the essential fatty acid, linoleic acid, measured in adipose tissue as an indicator of long term dietary intake, is inversely related to the risk of sudden cardiac death. DESIGN: A population case-control study. SETTING: A regional health district. SUBJECTS: 84 men (age 25-64 years) who died instantaneously or within 24 hours of the onset of symptoms with no history of coronary heart disease or medically treated hyperlipidaemia, and in whom coronary artery disease was diagnosed at postmortem examination as the primary cause of death, were compared with 292 age (to within two years) and sex matched healthy controls and their partners drawn from the general practitioners' records with whom the cases were registered. MAIN OUTCOME MEASURES: Fatty acid composition of adipose tissue and the risk of sudden cardiac death. RESULTS: Linoleic acid in adipose tissue was inversely related to the risk of sudden cardiac death. The estimated relative risk (95% CI) of sudden cardiac death was 5.7 (1.8 to 17.9) for the lowest quintile and 4.0 (1.2 to 12.9) for the next quintile of adipose linoleic acid in the control population when compared with the highest quintile. This inverse relation was independent of age, reported smoking habits, history of hypertension, and diabetes, although there was a close association with cigarette smoking. The estimated adjusted proportionate increase in risk (95% CI) of sudden cardiac death was 1.14 (1.03 to 1.23) for every 1% reduction of linoleic acid in adipose tissue. CONCLUSIONS: The percentage content of linoleic acid in adipose tissue was inversely related to the risk of sudden cardiac death. Populations with a high risk of sudden cardiac death may benefit from increasing their dietary intake of polyunsaturated fatty acid oils, principally from cereals and vegetables.

Adipose Tissue↗
PubMed1985

Lack of adverse effect of silicone implant on sarcoidosis of the breast.

Involvement of the breast by sarcoidosis is extremely rare, with only 11 case reports in the literature. The potential adverse interaction between silicone prostheses and this disease process poses an unusual clinical dilemma. However, two patients with sarcoidosis of the breast had silicone breast implants placed without exacerbation of their disease nor unusual periprosthetic complications. We conclude that sarcoidosis of the breast does not appear to be a contraindication to placement of silicone implants.

Adult↗
PubMed1979

Antibiotic penetration into normal and inflamed tissues as reflected by peripheral lymph.

The concentration of antibiotic in peripheral lymph reflects the tissue levels. Following microsurgical cannulation of the right lymphatic duct in 28 healthy rabbits, either penicillin-G, nafcillin, erythromycin, or cefazolin was given intramuscularly, and lymph and serum samples obtained at frequent intervals. Penicillin or nafcillin was administered to 14 additional rabbits with cellulitis of the right upper extremity. A serum sample drawn between one and two hours after an intramuscular injection, in general, reflects the peak lymph antibiotic concentration and hence the peak tissue concentration of the drug. After two hours the lymph level remains equal to or greater than the simultaneous serum level. The presence of inflammation did not alter the peak antibiotic levels. However, nafcillin required longer for equilibration in the inflamed state than in the uninflamed state, whereas penicillin-G equilibrated more rapidly in the presence of inflammation.

Animals↗
PubMed1978

Microsurgical two-layer vasovasostomy: laboratory use of vasectomized segments.

A microsurgical laboratory model is described which uses optimally preserved human vasectomy segments. These preserved specimens retain their natural appearance and handling qualities, permitting ready availability of material for practice, which is mandatory before clinical performance. If laboratory facilities are not available, the model can be used for practice in a convenient area of the operating suite.

Humans↗
PubMed1978

An experimental study of end-to-side microvascular anastomosis.

Forty-nine end-to-side arterial anastomoses were carried out in dogs. The saphenous artery was anastomosed to the femoral artery. Variations in technique were made regarding the shape of the aperture in the large artery and in the incident angle of the small artery. Blood flow was measured in the immediate postoperative period with electromagnetic flowmeters on the saphenous and femoral arteries. There was no significant difference in flow between each of the four types of anastomoses studied. In each of the flow was slightly, but not significantly, higher than the preoperative level.

Animals↗
PubMed1975

A new filtered sump tube for wound drainage.

A new filtered sump tube has been designed for drainage of collections of fluids from wounds without the danger of infection by airborne contaminants. A two-staged filter has been attached to the vent lumen that removes particulate matter and bacteria from the air that passes through the filter. A clinical evaluation of this tube confirms the superiority of sump drainage as compared with closed suction drainage in the removal of fluids from wounds or cavities.

Abdominal Injuries↗
PubMedDate not supplied

Maintenance of adequate hemodialysis access. Prevention of neointimal hyperplasia.

The maintenance of adequate hemodialysis vascular access is frequently complicated in the patient with polytetrafluoroethylene (PTFE) A-V hemodialysis grafts by venous anastomotic stenosis. This stenosis is caused by neointimal hyperplasia (NIH), a response to vascular injury. In this study, the authors prospectively analyzed the effect of a short-term regimen consisting of administration of two medications, heparin and low molecular weight dextran, on the development of NIH at the venous anastomosis in 79 patients with PTFE A-V hemodialysis grafts. In addition, they evaluated other parameters' effects on the development of NIH. In comparison with control subjects, heparin had some effect in minimizing the development of NIH in the PTFE grafts when evaluated radiologically at 3 months, although this effect was not statistically significant. Low molecular weight dextran, however, had no trend or statistically significant effect on this venous anastomotic narrowing. Interestingly, patient age, use of calcium channel blockers, and presence of diabetes mellitus (DM) all appeared to affect the development of NIH. Increasing age and use of calcium channel blockers was associated with decreased development of NIH; conversely, DM was associated with worsened NIH. In evaluation of access survival (time to first access failure), degree of venous anastomosis stenosis at 3 months was not predictive. Patient time on dialysis pre graft placement was the only measured parameter related to access failure. The method of dialysis pre graft placement (hemodialysis versus peritoneal dialysis) was not a significant factor in early access failure. Pharmacologic treatment of venous anastomotic narrowing in PTFE hemodialysis grafts due to NIH continues to be difficult. Short-term treatment with the tested medication failed to statistically affect NIH. Patient age, use of calcium channel blockers, and presence of DM were all factors in the development of NIH. Of measured parameters, time on dialysis pre graft placement was the only factor correlated with early access failure. In future treatment regimens, one should consider more prolonged treatment. In addition, noted risk factors should be considered when determining type of renal replacement therapy.

Adult↗