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Biomedical subjects

L Edwards

Publications and source records attributed to L Edwards.

At least 73 records · Page 4Linked to original sources

Double-ended pigtail polyethylene stents in management of benign and malignant ureteric obstruction.

Surgical urinary diversion for incurable pelvic malignancy has a high morbidity and mortality, and external drainage provides less than ideal palliation. Six patients with ureteric obstruction caused by cancer have been managed by operative or endoscopic insertion of self-retaining polyethylene tubes. These techniques also have applications in non-malignant disease, and the treatment of two patients with benign ureteric stricture is described.

Abdominal Neoplasms

Effect of infusing the branched-chain amino acids on concentrations of amino acids in plasma and brain and on brain catecholamines after total hepatectomy in the rat.

In totally hepatectomized rats supported by infusion of glucose, the concentrations of many amino acids in plasma and brain rose progressively over time, while the brain levels of norepinephrine decreased. Infusion of a solution containing glucose, leucine, isoleucine, and valine after hepatectomy greatly reduced the accumulation of other essential amino acids in plasma and brain. However, the decrease in brain norepinephrine content was not significantly affected by this infusion, suggesting that high brain concentrations of monoamine precursor amino acids are not the primary cause of norepinephrine depletion after hepatectomy.

Amino Acids

An objective comparison of transurethral resection and bladder neck incision in the treatment of prostatic hypertrophy.

Transurethral resection has become the operation of choice in almost all cases of benign prostatic enlargement. However, when the gland does not exceed 30 gm. bladder neck incision is easier to perform, results in a lower morbidity, and is less likely to be followed by incontinence and retrograde ejaculation. We studied 2 groups of men with proved obstruction. Complete urodynamic investigation was done on 51 patients before and on 44 patients after the operation. We compared our subjective and objective findings in the 2 groups. The conclusion suggest that bladder neck incision is as effective as transurethral resection in relieving the obstruction of prostatic enlargement in the presence of a small gland.

Humans

Plasma and skeletal muscle amino acids following severe burn injury in patients and experimental animals.

This study describes and analyzes sequential changes in plasma and skeletal muscle free amino acids following severe burn injury. Plasma free amino acids were determined in children (n = 9) with burns averaging 60% total body surface area and were compared with laboratory beagles (n = 44) which received a flame burn totaling 30% of their body surface area. In addition, needle biopsy specimens were obtained from the semitendonosus muscle in the animals to determine free intracellular amino acids. In both patients and animals the amount of total free amino acids in plasma fell following burn, suggesting relative protein deficiency. This drop was primarily due to a 47% drop in nonessential amino acids. However, plasma phenylalanine was consistently higher than normal following burn, and was strongly associated with death and weight loss in both animals and patients, especially when analyzed as a ratio with tyrosine. This finding suggested excessive catabolism, hepatic dysfunction, or both. Plasma levels of several amino acids correlated significantly with weight loss. Alterations in muscle free amino acids generally were similar to plasma amino acids. Exceptions were muscle alanine and glycine which strongly correlated with weight loss. However, the determination of muscle free amino acid profiles did not yield clinically useful information not available from plasma profiles. Plasma levels of liver enzymes suggested progressive hepatic dysfunction. These studies show that the laboratory beagle is a good model for studying the metabolic alterations of amino acids that accompany burn injury, since they mimic humans in many parameters which appear to be most useful with respect to clinical evaluation.

Amino Acids

Interstitial cystitis.

Twenty histologically proven cases of interstitial cystitis were investigated in an attempt to find evidence of a possible autoimmune mechanism in its aetiology. HLA tissue typing was performed, autoantibody profiles were obtained, and a questionnaire of the patients' past history completed, especially with respect to other autoimmune conditions. An experiment was designed to test the effect of sodium cromoglycate on rat bladders. The results are discussed in relation to the management of patients with interstitial cystitis.

Aged

Endourethral urethroplasty.

Following internal urethrotomy for treatment of strictures of the bulbous urethra, 11 patients had primary split skin grafts inlaid over the urethrotomy site. There were no operative complications and the results in 5 patients with a 9-month follow-up are good.

Adult

Serum total and free thyroxine and triiodothyronine during dynamic muscular exercise in man.

The effect of strenuous dynamic muscular exercise on serum-free thyroxine (FT4) and free triiodothyronine (FT3) concentrations has been studied in 10 healthy subjects. In the course of 7.8-19 min of treadmill exercise (protocol of R. A. Bruce), the group showed a mean increase in serum albumin concentration of 11.4% (P less than 0.01). Five subjects demonstrated an increase in FT4 concentrations (x = +54%) and five showed decreased FT4 (x = -36%). The difference in FT4 concentrations was accounted for primarily by acute alterations in dialyzable fraction T4 (DFT4) rather than total serum T4. Mean changes in DFT4 were statistically significant (P less than 0.02) when increased FT4 and decreased FT4 groups were compared. Acute exercise was accompanied by a 9% decrease in dialyzable fraction T3 (DFT3) (P less than 0.02) in the 10 subjects, but the concomitant decrease in FT3 concentration was not significant. Changes in DFT4 and DFT3 and FT4 and FT3 concentrations were not correlated. Trends in double product (heart rate times blood pressure) with maximal exercise and in double-product recovery after exercise suggested that increased FT4 concentrations developed in subjects who were physically better trained.

Adult

Inhibition of dopamine-induced release of growth hormone by thyrotropin-releasing hormone.

The effects of thyrotropin-releasing hormone (TRH) and dopamine (DA) on serum growth hormone (GH) levels were examined in the adolescent male baboon. Intravenously administered DA (40 microgram/kg-min-1 for 20 min) raised serum GH and glucose and lowered serum insulin concentrations but caused no increase in blood pressure. Concomitant intravenous infusion of TRH at 2 doses (96 ng/kg-min-1 and 40 microgram/kg-min-1 for 20 min) blocked the DA-induced increase in serum GH. The relatively low effective doses of TRH used to suppress the DA-induced GH increase suggest an interaction with catecholamines at the hypothalamic and/or pituitary to influence GH release.

Animals