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Biomedical subjects

R Smith

Publications and source records attributed to R Smith.

At least 1,423 records · Page 79Linked to original sources
PubMed1980

DOPA metabolism in neuroblastoma.

Blood plasma samples from 60 neuroblastoma patients prior to, during, and following treatment were studied for their content of circulating DOPA using a radioenzymatic assay. Normal values were established from children who were tumor-free or had other nonneurogenic tumors. The highest plasma DOPA concentration in tumor-free or nonneuroblastoma controls was 5.3 ng/ml with a mean of 2.15 ng/ml. Most neuroblastoma patients (28/31) with active disease had DOPA values above this level. Only one out of 30 "successfully" treated patients without evidence of disease was encountered with an abnormally high level. In treated patients, elevated values forewarned of impending clinical recurrence or persistent tumor. Cerebrospinal fluid DOPA levels in one patient with cerebral neuroblastoma were extraordinarily high and suggests that this assay may prove useful to distinguish neuroblastoma from other central neuroectodermal or metastatic tumors. Plasma DOPA appears to be a reliable predictive and diagnostic test for neuroblastoma.

Adolescent↗
PubMed1980

Dibromochloropropane and its effect on testicular function in man.

This study represents the largest series to date documenting the gonadotoxic effect in humans of dibromochloropropane, a widely used pesticide. Three semen analyses, serum hormonal determinations (luteinizing hormone, follicle-stimulating hormone and testosterone) as well as genital examinations were completed for 228 workers at 2 chemical production sites and consisting of a dibromochloropropane-exposed and non-exposed cohort. Parameteric and non-parametric statistical analyses of the data sets of the sperm densities from the 2 subpopulations demonstrated statistical significance (p less than 0.10) at the short-term (1.5 years) manufacturing plant. Log transformation of the sperm count and hourly exposure data were necessary to develop meaningful statistical conclusions. The serum concentration of follicle-stimulating hormone as a group mean was significantly greater at both production sites for the exposed cohort when compared to the non-exposed participants but decreased by 10 levels of magnitude when the group demonstraing shorter but more recent exposure was compared to those from the plant with longer chemical production. Finally, a dose-response model suggested significant changes in sperm density at the short-term but more recently operated production site when more than 100 adjusted hours of exposure were exceeded, while the longer operated but longer closed facility demonstrated a significant impairment only when more than 1,000 adjusted hours of dibromochloropropane exposure were surpassed. This difference in exposure data may reflect regenerative changes in the tests once the gonadotoxic substance had been removed but exact nature of the dibromochloropropane effect and the possibility of a "no effect" concentration remain to be defined clearly.

Antinematodal Agents↗
PubMed1980

Scientific thought and the boundary of insanity and criminal responsibility.

The insanity defence is considered in terms of the operation of incommensurable scientific and legal discourses, a dualism which in turn is held to reflect individualist values. This analysis is used to explain both the recurring nature of medico-legal controversy and the historical results of the defence in Victorian England.

Criminal Psychology↗
PubMed1980

Relationship between the basal blood alanine concentration and the removal of an alanine load in various clinical states in man.

1. Blood alanine was measured in six patients undergoing total hip replacement and in four normal subjects starved for 4 days. Hypoalaninaemia occurred in both groups and persisted in the surgical patients despite an adequate diet. The blood alanine was also low in four insulin-dependent diabetic patients and in four patients with muscular dystrophy; it was normal in four patients with cirrhotic liver disease. 2. The removal of an intravenous L-alanine load (12 g; 133 mmol) was significantly increased after surgery and in the diabetic patients, unaltered by starvation, and decreased in the cirrhotic patients. 3. Increases in blood glucose were observed when alanine infusion was performed 6 h after surgery and after 3 days' starvation. Increases in blood lactate and pyruvate always occurred after alanine infusion but were most marked 6 h after surgery. 4. These results show that the metabolic response to an alanine load and the ability of the body to remove it alter with change in physiological state, and that the hypoalaninaemia after surgery and in diabetes is related to an increased removal of intravenous alanine, whereas that during starvation is not.

Adolescent↗
PubMed1980

Plasma alpha 2HS-glycoprotein concentration in Paget's disease of bone: its possible significance.

1. The plasma concentration of the alpha 2HS-glycoprotein has been measured in 58 normal adults and in patients with Paget's disease of bone before (24) and during treatment (16). 2. The average plasma alpha 2HS-glycoprotein was lower in the patients with Paget's disease than in the normal adults and was inversely related to plasma alkaline phosphatase activity (r = -0.55, n = 24, P less than 0.001). 3. When the patients with Paget's disease were treated with either diphosphonate or calcitonin, the plasma alpha 2HS-glycoprotein concentration increased towards normal. In those patients treated with calcitonin, this increase was too rapid to be entirely accounted for by a cessation of bone formation.

Aged↗
PubMed1980

The removal of infused leucine after injury, starvation and other conditions in man.

1. To investigate the effects of starvation, elective surgery, accidental injury and other clinical conditions on the metabolism of branched-chain amino acids in man, we have measured the basal concentration of leucine and the removal of metabolic effects of infused L-leucine. 2. The blood concentration of leucine as significantly increased by surgery, starvation and accidental injury, and decreased in cirrhosis. It tended to increase in diabetes and was unaffected by muscular dystrophy. 3. The half-life of infused leucine was nearly doubled by 4 days of complete starvation, unaltered by surgery and decreased by severe accidental injury, Infusion with Intralipid, which increased free fatty acid and ketone-body concentrations, had no effect on the removal of a leucine load. The clearance rate of infused leucine was reduced in diabetes and muscular dystrophy and increased in cirrhosis. 4. The effects of infused leucine on blood glucose and ketone bodies differed according to the groups studied. 5. Since the traumatized patients were given sufficient energy and nitrogen and disposed of a leucine load at a different rate from the starved patients, the causes of the increase in blood concentration of leucine in these two conditions are different.

Adolescent↗
PubMed1980

The effect of 3-methylhistidine in food on its urinary excretion in man.

1. To establish whether 3-methylhistidine in food is quantitatively excreted in the urine, five normal adults on a vegetarian diet were given known amounts of 3-methylhistidine in meat or fish. The mean cumulative 5-day increment in 3-methylhistidine excretion in non-hydrolysed urine accounted for an average of 90% of the 3-methylhistidine given during the first 3 days of this period. 2. To define the variation in urinary 3-methylhistidine on a constant mixed intake, the daily 3-methylhistidine excretion was measured for 6 days in four patients on a metabolic "balance" diet. The mean daily variation was less than 10%. 3. The results show that under the conditions of this study the increase in urinary 3-methylhistidine above basal levels can be quantitatively accounted for by the 3-methylhistidine content of additional food; in subjects on a constant diet it should be possible to detect relatively small changes in 3-methylhistidine excretion.

Adult↗
PubMed1980

Early biochemical changes and severity of injury in man.

To investigate whether biochemical changes soon after injury could be used as a measure of its severity or to predict its outcome we have examined the relationships of an injury severity score, initial blood metabolite concentrations, and subsequent biochemical changes in 33 injured patients. At about 4 hours after injury severity was related directly to blood lactate, pyruvate, and alanine (p less than 0.01), and inversely to blood ketone body concentrations (p less than 0.05). In 19 patients the daily total nitrogen, histidine, and 3-methylhistidine excretion was measured for 7 days. Only total urinary nitrogen was related to injury severity; 3-methylhistidine was inversely related to initial ketone body concentration; and histidine excretion was related to initial lactate, pyruvate, and alanine concentration. It is concluded that certain early biochemical measurements are significantly related to the severity of injury, and thus may be of practical importance.

Adolescent↗
PubMed1980

Pituitary function in normoprolactinaemic infertile men receiving bromocriptine.

A double blind trial of bromocriptine 7.5 mg daily versus placebo was carried out in ten infertile men. Pretreatment basal plasma prolactin, thyroid stimulating hormone (TSH) testosterone and luteinizing hormone (LH) concentrations were normal, but plasma follicle-stimulating-hormone (FSH) was raised in four individuals. After 4 months treatment with bromocriptine a significant fall in plasma prolactin was observed (P less than 0.01), both under basal conditions and following thyroid stimulating hormone releasing hormone (TRH). Basal plasma gonadotrophin, testosterone and thyroid stimulating hormone (TSH) concentrations did not alter. No change in sperm density, volume or motility was noted. However an apparent fall in the peak plasma LH (but not FSH) response to gonadotrophin releasing hormone (LHRH) was observed in patients receiving bromocriptine. This reduction in plasma LH responsiveness was significant when compared with the baseline response (P less than 0.05) but failed to reach significance when compared with the placebo response. It is concluded that prolonged bromocriptine therapy in normoprolactinaemic men does not suppress FSH secretion, and any reduction in plasma LH responsiveness to LHRH is not accompanied by a significant fall in plasma testosterone.

Adult↗
PubMed1980

Tests of fetal wellbeing in the third trimester of pregnancy.

Five different products secreted by the fetoplacental unit into the maternal circulation were measured in 272 patients when they were 34 weeks pregnant. The most useful indicator of present pathology or future complications of pregnancy was a placental protein, pregnancy associated plasma protein. A which was raised in pre-eclamptic toxaemia, antepartum haemorrhage and premature labour. The highest values were recorded in pre-eclampsia before any signs of the disease were evident. Schwangerschafts protein 1 was also raised in pre-eclampsia and antepartum haemorrhage but only after the disease had presented. Placental lactogen was also raised in pre-eclampsia and its measurement may have some predictive value. Total oestriol was lowered in fetal growth retardation and the unconjugated steroid raised in pre-eclampsia and lowered in retarded fetal growth.

Estriol↗