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Biomedical subjects

S E Hall

Publications and source records attributed to S E Hall.

At least 91 records · Page 5Linked to original sources
PubMed1980

Glucose and free fatty acid turnover in thyrotoxicosis and hypothyroidism, before and after treatment.

Glucose and free fatty acid (FFA) turnover (RT) were measured by isotopic methods in groups of patients with thyrotoxicosis and hypothyroidism and compared with normal subjects. Patients with thyrotoxicosis were then studied after treatment with oral propranolol and again after treatment with carbimazole. Patients with hypothyroidism were studied again after treatment with thyroxine. Glucose RT was increased by about a third in thyrotoxicosis (12.7 mumol. min.-1 kg-1 +/- 1.0 SEM compared to 9.5 +/- 0.5 in normal subjects) while FFA RT was doubled (12.5 mumol. min.-1 kg-1 +/- 1.2 compared to 6.3 +/- 0.9 in normals). Propranolol was without effect, but carbimazole normalized these variables. In hypothyroidism both glucose and FFA RT were normal (9.1 +/- 0.7 and 6.7 +/- 0.9 respectively). Mean glucose and FFA RT both rose following thyroxine treatment, but not significantly; the post-treatment values remaining within the normal range (10.3 +/- 0.7 and 7.0 +/- 1.3 respectively). Oxidation of FFA, as estimated by 14CO2 excretion, was increased in thyrotoxicosis (42.8% +/- 2.9 SEM compared to 34.8 +/- 2.3 in normal subjects) and fell with carbimazole treatment (34.7 +/- 4.1). In hypothyroid subjects FFA oxidation increased following thyroxine treatment (from 34.4 +/- 4.1). In hypothyroid subjects FFA oxidation increased following thyroxine treatment (from 34.4 +/- 3.3 to 46.2 +/- 3.6).

Adult↗
PubMed1979

Glucose and free fatty acid turnover in normal subjects and in diabetic patients before and after insulin treatment.

Turnover rates of glucose and free fatty acids were measured, using 3H-glucose and 14C-l-palmitic acid as tracers, in insulin-requiring diabetic patients at presentation and after insulin treatment. Correlations were sought with rates of substrate oxidation, determined independently from respiratory exchange, and with plasma hormone concentrations. The rates of appearance of glucose and of free fatty acids were increased in the diabetics to 17.6 and 10.2 micronmol min-1 kg-1 respectively. Both rates fell to normal (13.3 and 7.1 micronmol min-1 kg-1) after insulin. In the untreated state there was an inverse relationship between the rates of utilisation of glucose and free fatty acids (r = 0.61; p less than 0.05). It is suggested that this relationship represents the impairment of peripheral glucose utilisation by free fatty acids and by ketone bodies in vivo, so far only demonstrated in vitro. The tracer calculated rates of glucose utilisation correlated well over a wide range with the respiratory quotient in untreated diabetics, while respiratory quotient was inversely related to free fatty acid turnover rates. In untreated diabetics plasma cortisol and 3,3', 5'-triiodothyronine (rT3) were increased whereas thyroxine and 3,5,3'-triiodothyronine (T3) were decreased. 3,5,3'-Triiodothyronine concentration was closely related to the metabolic clearance rate of glucose (p less than 0.05), while cortisol concentrations correlated with glucose production (p less than 0.02) and blood ketone body concentration (p less than 0.02). It is concluded that glucose overproduction is the major contributor to the hyperglycaemia of untreated diabetes.

Adult↗
PubMed1978

The effect of propranolol on thyroid hormones and oxygen consumption in thyrotoxicosis.

The possibility that propranolol may exert its beneficial actions in thyrotoxicosis by an effect on thyroid hormone concentrations has been investigated by measuring these and oxygen consumption in a group of thyrotoxic patients before and after treatment with propranolol. Following treatment a significant fall in plasma T3 concentration and oxygen consumption occurred and a direct correlation was found between these two variables. Propranolol may, therefore, exert some of its beneficial effects in thyrotoxicosis by an action on T3 metabolism.

Adult↗
PubMed1977

The turnover and conversion to glucose of alanine in newborn and grown dogs.

The extent of transfer of carbon atoms from alanine to glucose was examined in pups and grown dogs. [U-14C]Alanine and [2-3H]glucose were injected intravenously and by using the SAAM-26 program a compartmental model was formulated from the tracer data to quantify the kinetics of the alanine- and glucose-carbon system. A 3-compartment model was necessary to describe the alanine-carbon kinetics. Strict identification of these compartments with physiological counterparts was not possible. The overall transport (turnover) rate of alanine-C was found not to change significantly with age when calculated on the basis of body weight. Carbon atoms from alanine reach glucose by three identifiable pathways of different speed. The kinetics suggest that the different pathways are at least in part due to differences in the metabolism of the three carbon atoms of alanine. In pups less than 11 days of age 45-49% of the carbon atoms leaving the alanine subsystem enter glucose; in adults it was 70%. In young pups 18-19% of glucose-C utilized was derived from alanine-C, whereas in adults, 62%. Accordingly a smaller percentage of carbon atoms utilized as alanine appears in glucose and a smaller percentage of glucose-C is derived from alanine in pups than in grown dogs.

Age Factors↗
PubMed1976

Effects of age and fasting on gluconeogenesis from glycerol in dogs.

The extent of gluconeogenesis from glycerol was examined in pups and adult dogs. With use of the SAAM-26 program, a four compartment model was formulated from tracer data to calculate the kinetics of the glycerol:glucose system. In the postabsorptive state gluconeogenesis from glycerol declines with age: 13.8% of glucose carbon originated from glycerol in 0- to 4-day-old pups, 6% in adults. Approximately 50% of glycerol carbon is converted to glucose carbon independent of age. During fasting, a) the percentage of glucose carbon arising from glycerol carbon increased to 13.3% and 10.3% in adult dogs and pups 5-19 days old, respectively, in younger pups it declined to 3.4%; b) glycerol production increased in adults, but decreased in the youngest pups; c) glucose production and utilization decreased at all ages, and a smaller percentage of glycerol carbon was converted to glucose carbon, especially in the youngest pups. Thus in neonates fasting decreases gluconeogenesis from glycerol.

Aging↗
PubMed1976

Plasma glucagon in pups, decreased by fasting, unaffected by somatostatin or hypoglycemia.

In pups less than 4 days old, the mean basal plasma immunoreactive glucagon (IRG) level was about 3 times higher than in adult dogs. This high level decreased with age, and in pups older than 12 days the mean plasma IRG level did not differ from that in adults. Insulin-induced hypoglycemia did not raise plasma IRG concentration in young pups. Fasting decreased plasma IRG in young, but not in older pups. This decrease is consistent with the decrease in gluconeogenesis and in contrast to the metabolic adjustments observed in the adult organism. In pups less than 7 days old, both the pancreas and gastric mucosa contained considerably more IRG than the normal value reported for adult dogs. Gastroduodenal IRG was immunologically indistinguishable from pancreatic glucagon. In pups, somatostatin did not decrease the plasma concentration of either IRG or immunoreactive insulin (IRI) and caused no change in plasma glucose or in the rates of glucose production and utilization calculated from experiments with tracers. The experiments indicate that in pups the pancreatic and gastric alpha-cells are unresponsive to stimuli normally effective in grown dogs.

Age Factors↗
PubMed1975

Re-incorporation of carbon atoms into plasma glucose in newborn dogs.

The ratio of the total turnover rate of glucose calculated with [2-3H]glucose as the tracer and the irreversible disposal rate of glucose, calculated with [U-14C]glucose as the tracer was found to be 1.35 +/- 0.28 SD (+/- 0.08 SEM) in dogs 1-33 days of age. This value was unrelated to age and to the level of glucose in the plasma. Accordingly, under basal conditions the overall re-incorporation of carbon atoms into newly released glucose in pups is nearly identical with that found in grown dogs.

Aging↗
PubMedDate not supplied

Glucose and free fatty acid turnover in Cushing's syndrome.

Glucocorticoids are known to have acute effects on glucose and free fatty acid (FFA) metabolism. The effects of the longstanding hypercorticism of Cushing's syndrome were studied by isotopic techniques in a group of Cushingoid patients compared to a control group. In the Cushing's group, glucose production and utilization rates were significantly higher than in control subjects, while FFA turnover also tended to be higher, but not significantly. It is suggested that increased glucose production is the main cause of the hyperglycemia seen in Cushing's syndrome.

Adult↗
PubMedDate not supplied

Recent advances in solid phase synthesis.

The use of solid phase synthesis continues to expand as chemists identify methodology that enables complex reactions. Recent efforts in this area have focused on new carbon-carbon bond forming reactions as well as a variety of heterocyclic systems. These examples are described along with updates on new linking strategies for solid phase synthesis.

Chemistry, Organic↗
PubMedDate not supplied

Multiplicity of inputs in the afferent path to cat auditory cortex neurons revealed by tone-on-tone masking.

This report presents preliminary evidence on the effect of continuous tonal maskers on the responses of single primary auditory cortical neurons in anesthetized cats to tonal signals across their effective frequency ranges 10 dB above characteristic frequency threshold. Tonal maskers had three kinds of effects. In many cells, the masker produced a generalized suppression of responses to tones across the response area. In some neurons, typically those with monotonic intensity profiles, tonal maskers on one side of the response area produced a selective suppression of responses to tone signals on the same side as the masker. This differential sensitivity to the masker is evidence of independent inputs to those neurons on the high- and low-frequency sides of their excitatory response areas. Finally, in non-monotonic neurons, tonal maskers at the high-frequency edge of the excitatory response area produced enhanced responses to tonal signals on the same side of the response area as the masker. We interpret this as a release from the effect of an inhibitory input located at the high-frequency edge of the response area.

Acoustic Stimulation↗
PubMedDate not supplied

Enhancing volunteer effectiveness.

The characteristics of being genuine/congruent, having an unconditional positive regard and an empathic understanding, can be integrated into the training volunteers receive prior to assignment with patients/families. Understanding and practicing these concepts may further promote the interpersonal relationships volunteers have with patients/families and other hospice professionals.

Empathy↗
PubMedDate not supplied

Enhancing volunteer effectiveness: a didactic and experiential workshop.

Presented is an actual workshop to enhance the personal and professional development of volunteers and their relationship with others. This workshop is a follow up to information in the article, "Enhancing volunteer effectiveness" which appeared in the May/june (1996) issue of The American Journal of Hospice & Palliative Care.

Curriculum↗