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Biomedical subjects

R G Thompson

Publications and source records attributed to R G Thompson.

At least 55 records · Page 3Linked to original sources

Anorectal sepsis: microbiology in relation to fistula-in-ano.

One hundred and sixty-five patients presented in a 4-year period: 68 (41.2 per cent) had had previous anorectal sepsis and in 56 of these patients (82.3 per cent) the presenting sepsis was at the site of the previous abscess. The abscesses were drained and pus was sent for culture; any fistula, if found, was laid open. A second examination under anaesthesia was performed within 7--10 days if no fistula had been found. The pus from 114 patients grew bowel-derived organisms; 62 (54.4 per cent) fistulas were found. The pus from 34 patients grew skin-derived organisms but no fistula was demonstrated in this group. It is suggested that a second examination need only be performed if culture of the pus grows bowel-derived organisms: anorectal abscesses which grow skin-derived organisms are not associated with a fistula.

Abscess↗

Free and total insulin integrated concentrations in insulin dependent diabetes.

Studies of the 24 hr insulin concentration profiles in diabetic subjects on chronic exogenous insulin have been hampered by the presence of endogenous anti-insulin antibody, which gives spurious estimates of radioimmunoassayable insulin concentrations. The introduction of polyethylene glycol precipitation of endogenous antibody has allowed development of reliable assays for determination of free and total insulin concentration in subjects on insulin therapy. This article reports our observations of plasma free and total insulin concentration in 50 Type I and Type II ambulatory insulin dependent diabetics, utilizing a continuous 24 hr blood withdrawal technique. In response to exogenous insulin, study subjects had marked elevations in insulin concentrations compared to controls. Mean free insulin integrated concentration was 3.5-fold higher in diabetics than nondiabetics. Mean total insulin integrated concentration was 868 microunits/ml, more than 20 times in excess of total insulin concentration in nondiabetics. There was a wide range among diabetics in the percentage of total insulin in the free insulin fraction. Neither free nor total insulin integrated concentration correlated with dose of exogenous insulin. Free and total insulin concentration profiles showed a limited range of variation in insulin concentration during the 24 hr of study, no subject having a profile that mimicked that observed in nondiabetic subjects. Glucose integrated concentration showed no correlation with free insulin integrated concentration, however, it did correlate inversely with the percentage of total insulin in the free insulin fraction. These data emphasize the difficulty in establishing normal patterns of insulin among diabetic subjects on conventional subcutaneous insulin therapy.

Adolescent↗

Methylphenidate treatment of hyperactive children: effects on the hypothalamic-pituitary-somatomedin axis.

To further define the influence of methylphenidate on the growth hormone-somatomedin axis and prolactin secretion, serum growth hormone and prolactin concentrations were assessed over 24 hours and in response to provocative stimuli. The nine hyperactive subjects were all studied during methylphenidate therapy and after drug discontinuation, Diurnal patterns of growth hormone and prolactin concentrations were assessed using an ambulatory, continuous blood withdrawal procedure to ensure that activity, caloric intake, and sleep patterns mimicked normal schedules. No significant difference in integrated concentration of growth hormone, fasting somatomedin concentration, or prolactin integrated concentration was detected between subjects receiving or not receiving methylphenidate. There was a significant increase in peak growth hormone response to arginine stimulation among subjects receiving methylphenidate therapy; however, this appeared to correlate with acute methylphenidate administration. These data do not support the hypothesis that growth defects in hyperactive children treated with methylphenidate are caused by alteration in the hypothalamic-pituitary-somatomedin axis.

Adolescent↗

Biochemical specificity of septal hyperreactivity: a behavioral discrimination.

Intra-septal injections of specific monoamine and cell body neurotoxins were used to determine the anatomical and biochemical elements critical to both short and longer term changes in reactivity normally seen after septal lesions. A multivariate discrimination performed on the basis of tactile, foot-shock and heat responsiveness revealed that septal lesions have a unique effect not accounted for by specific monoamine induced degeneration. Injections of 6-hydroxydopa and monosodium glutamate had slight effects on heat and shock responsiveness not at all comparable in degree or kind to septal lesion effects. Decreased hippocampal, but not hypothalamic, levels of norepinephrine may be associated with the longer term increased responsiveness to shock and heat in animals with septal lesions.

5,7-Dihydroxytryptamine↗

Cardiac function in primary hypothyroidism.

Cardiac chamber dimensions and myocardial function were studied in 15 children with primary hypothyroidism prior to and after thyroxine therapy. Small pericardial effusions were detected in 11 of 15 subjects before therapy, which resolved in nine of 11 subjects after initiation of thyroxine replacement. There was no association between the severity of the thyroid failure and the presence of effusion, and no evidence of cardiac compromise due to effusions. No significant abnormality in cardiac chamber or myocardial dimensions, systolic time intervals, or indices of myocardial contractility was detected among the hypothyroid children as compared with a normal population. Neither myocardial dimensions nor contractility indices changed significantly on reestablishment of normal thyroxine concentrations with exogenous hormone. These data refute the existence of a myocardiopathy associated with hypothyroidism in children.

Adolescent↗

Integrated concentration of growth hormone in juvenile-onset diabetes.

Twenty-four-hour patterns of plasma growth hormone concentrations were evaluated during 50 studies of 42 subjects with juvenile-onset diabetes mellitus. Blood was sampled continuously over 24 h using a portable peristaltic pump under conditions in which subjects remained ambulatory and maintained their daily dietary and insulin regimens. All diabetics showed diurnal patterns characterized by frequent episodes of secretion of growth hormone. The mean 24-h concentration of growth hormone, designated the integrated concentration, was significantly higher among juvenile-onset diabetics (P less than 0.001) than it was in age- and sex-matched nondiabetic populations. Juvenile-onset diabetics younger than 20 yr had significantly higher (P less than 0.005) growth hormone integrated concentrations than did older juvenile-onset diabetics. There was no statistically significant correlation between the integrated concentrations of glucose and growth hormone; thus, the study failed to provide us with support for the hypothesis that elevated growth hormone concentrations in diabetics are a consequence of hyperglycemia. Variability of diurnal glucose concentrations was positively correlated (P less than 0.015) with the growth hormone integrated concentration among juvenile-onset diabetics. Our observations indicate that rapid declines in plasma glucose concentration or episodes of absolute hypoglycemia were significant factors, contributing to both the elevated integrated concentration and the secretory spiking of growth hormone observed in the diabetic population.

Adolescent↗

Triglyceride concentrations: the disaccharide effect.

The mean 24-hour or integrated concentration of triglyceride is significantly higher when dietary sucrose is provided rather than an equivalent amount of its component monosaccharides, glucose and fructose. In contrast, the plasma triglyceride concentration after a 12-hour fast is not significantly different.

Adult↗

Serum cholesterol and triglycerides in children with growth hormone deficiency.

To test the hypothesis that hyperlipidemia is characteristic of growth hormone deficiency in childhood, we have measured serum cholesterol and triglyceride concentrations in 24 euthyroid children with growth hormone deficiency. Although modest elevations of cholesterol and/or triglyceride above the 95th percentile for age, race, and sex were present in 46% of the children studied, the mean (+/- 1 SD) cholesterol of 173 +/- 36 mg/dl and the mean triglyceride of 80 +/- 42 mg/dl were not significantly different from published normal mean values. Administration of human growth hormone for 4 mo to 15 of these subjects did not alter these mean cholesterol and triglyceride values, but did result in a marked improvement in the growth rate. Some individuals (n = 6) with a subnormal growth response to therapy and/or a low serum thyroxine and high serum cholesterol were treated for an additional 4 mo with growth hormone and thyroid hormone together. There was a statistically significant decrement in serum cholesterol in this group. We conclude that modest hyperlipidemia does exist in some children with growth hormone deficiency. Subclinical hypothyroidism may play a role in the hypercholesterolemia of some children, as may growth hormone deficiency itself. Any association of growth hormone and lipid metabolism remains to be clarified.

Adolescent↗

Triglyceride integrated concentrations: effect of variation of source and amount of dietary carbohydrate.

The effect of changes in the amount of dietary carbohydrate (45 or 65% of total energy) and in the source of carbohydrate (sucrose or corn syrup) on plasma triglyceride and cholesterol concentrations was studied in eight healthy males. Subjects ingested each of the four formula diets for 10 days in a latin square sequence. Diet-induced response was assessed by measurement of plasma lipid concentrations in blood obtained after overnight fast and by measurement of the mean plasma lipid concentrations--designated the integrated concentration--of blood obtained by 24 hr continuous blood withdrawal. The fasting plasma triglyceride concentration increased significantly during ingestion of the high carbohydrate diet (P less than 0.005) but was not significantly influenced by the source of carbohydrate calories. The 45% carbohydrate diets induced larger meal associated plasma triglyceride variation than 65% diets. Sucrose-containing diets induced significantly higher plasma triglyceride integrated concentrations than corn syrup diets, whether provided as 45% (P less than 0.05) or 65% (P less than 0.005) of total energy. Diet-induced changes in fasting or integrated plasma cholesterol concentration were minimal.

Adult↗

Bystander-initiated cardiopulmonary resuscitation in the management of ventricular fibrillation.

We assessed the influence of bystander-initiated cardiopulmonary resuscitation upon outcome in 316 consecutive patients treated for out-of-hospital ventricular fibrillation. Of 109 patients who received bystander-initiated cardiopulmonary resuscitation, 47 (43%) were ultimately discharged home. Of 207 patients for whom resuscitation was delayed until arrival of fire department personnel, 43 (21%) survived (P less than 0.001). Improved survival was largely due to a reduction in subsequent hospital mortality rather than to a higher rate of initially effective resuscitation. In a separate analysis of 118 patients treated at a single institution after resuscitation, the reduced hospital mortality reflected a decrease in deaths due to shock and to anoxic encephalopathy. In addition, neurologic dysfunction was significantly less common if bystanders had initiated cardiopulmonary resuscitation. Bystander participation in cardiopulmonary resuscitation represents an important adjunct to a rapid-response emergency care system.

Consciousness↗

A new method of patellectomy for patellofemoral arthritis.

Total patellectomy, although it has a biomechanical disadvantage in that it may lead to a degree of quadriceps weakness, is frequently indicated in selected patients. Numerous different techniques of performing patellectomy have been described. In this paper, we present a technique of performing a patellectomy in which the continuity of the quadriceps mechanism is not disrupted and the vastuc medialis is advanced. Twenty-six patients (twenty-nine knees) in whom the procedure was performed were studied retrospectively. The findings in this series showed 90 per cent good or excellent results, two cases of extensor lag, an average of 118 degrees of knee flexion, minimum quadriceps atrophy with good strength, and minimum postoperative immobilization. The method presented has the important advantage of an easier, smoother postoperative knee-rehabilitation period, which is extremely advantageous in elderly patients.

Adolescent↗