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Biomedical subjects

G Williams

Publications and source records attributed to G Williams.

At least 739 records · Page 41Linked to original sources
PubMed1982

Urinary unconjugated 5 alpha-androstane-3 alpha, 17 beta-diol in patients with prostatic tumours.

A sensitive and reliable radioimmunoassay (RIA) for urinary unconjugated 5 alpha-androstane-3 alpha, 17 beta-diol is described. The mean overall recovery of unconjugated 5 alpha-androstane-3 alpha, 17 beta-diol was found to be 57.4%. The sensitivity of the assay was 79 fmol per assay tube and the intra and inter-assay variations ranged between 7.2% and 11.4%. The mean +/- SEM for the concentration of this androgen in the urine of normal men was 339.6 +/- 66.8 nmol/24 h. The corresponding values for patients with benign prostatic hypertrophy (BPH) and carcinoma of the prostate (Ca) were 297.8 +/- 44.7 and 1592.1 +/- 622.7 respectively. The mean value for Ca patients was significantly higher than either BPH (p less than 0.05) or normal subject (p less than 0.02), suggesting a differential urinary excretion pattern for unconjugated 5 alpha-androstane-3 alpha, 17 beta-diol between BPH and Ca patients. It is concluded that the combined measurement of this androgen in the plasma and urine provides a more accurate assessment of the profile of this hormone than a single plasma estimation.

Adult↗
PubMed1982

Structural factors influencing the ability of compounds to inhibit hydroxyapatite formation.

For a compound to inhibit potently the transformation of amorphous calcium phosphate into hydroxyapatite, it is suggested that the minimum structural requirement is a phosphate group and, at some other position, either another phosphate group preferably or a carboxylic moiety. Primary amino groups abolish inhibitor potential. Inhibitor potency is modified by various secondary factors, including the number and proximity of active groups, their stereochemistry, steric factors, the lability of the molecule, and in special instances its lipophilicity. Parameters used to monitor the transformation indicate that inhibitors can be grouped into two classes, and it is suggested that this is because one class acts as a hydroxyapatite crystal growth inhibitor. The close proximity of two phosphate groups or of a phosphate and multiple carboxylic groups is proposed to determine in part whether or not a compound acts as a crystal growth inhibitor. Further, bulky side groups render a molecule inactive as a crystal growth poison, although it will still inhibit by other mechanisms.

Adenosine Triphosphate↗
PubMed1982

Captopril pharmacokinetics and the acute hemodynamic and hormonal response in patients with severe chronic congestive heart failure.

Twelve patients with severe chronic congestive heart failure (CHF) underwent simultaneous evaluation of the pharmacokinetic, pharmacodynamic, and neurohumoral actions of a single 25 mg oral dose of the angiotensin-converting enzyme (ACE) inhibitor captopril (CPT). Following drug administration, which raised plasma renin activity (PRA) and thereby indicated significant ACE inhibition, both free (unchanged) and total CPT (including active metabolites) were detectable in the blood with 40 minutes and peak blood levels of the agent were recorded 1 hour after CPT. Total CPT concentration was higher and persisted longer than free CPT, which became virtually nondetectable 8 hours after ingestion. Concomitantly, left ventricular function was markedly augmented by the oral ACE inhibition in all patients, with the magnitude of this improvement being closely related to the baseline PRA. Thus, the overall hemodynamic response to CPT, which rapidly appears in the bloodstream following drug intake in patients with advanced CHF, is a function of the extent of baseline renin-angiotensin-aldosterone activity.

Adult↗
PubMed1982

Erythrocyte - endothelial cell adherence in sickle cell disease, diabetes mellitus, and falciparum malaria: adverse effects reversed with piracetam.

The erythrocytes of patients with sickle hemoglobin, diabetes, and Falciparum malaria adhere disproportionately to endothelial cells. Such pathophysiological activity compromises the microcirculation and results in clinical disease. Since Piracetam (2-oxo-1 pyrrolidine acetamide) has been shown to have a number of clinically beneficial actions on the formed elements of the blood including disengagement of adherent diabetic and sickle erythrocytes there is a rational basis for the trial of Piracetam as an adjuvant drug in SS disease and in diabetes mellitus to improve function of the microcirculation. For similar but somewhat more complex reasons Piracetam may potentiate the efficacy of anti-malarial drugs at any given dosage. Piracetam, a drug known to be safe in a decade of clinical usage, merits serious study in the 3 cited diseases.

Anemia, Sickle Cell↗
PubMed1982

Control of severe vesical haemorrhage by therapeutic embolisation.

Therapeutic embolisation is now recognised as having a role in the management of bladder haemorrhage and is particularly valuable in severe cases where the patient's life is at risk. This paper describes the procedures which were used to manage two patients with massive haematuria, from a tumour in one case and from an arterial malformation in the other. Previous reports indicate that haemorrhage from a bladder tumour can usually be controlled by embolisation which is limited to the tumour itself but haemorrhage due to post-radiation telangiectasis requires more extensive arterial occlusion and this was taken into account in planning the embolisation procedure in the first case. Neither patient developed gluteal pain after embolisation which was probably due to the fact that the superior gluteal arteries were not completely occluded. The left axillary approach was used as a catheter passing down the aorta can usually be manipulated into the internal iliac arteries and their smaller branches on both sides without difficulty.

Adult↗
PubMed1982

Captopril kinetics in chronic congestive heart failure.

We investigated the kinetics of 25 mg captopril by mouth in 12 patients with congestive heart failure and correlated them with the hormonal and hemodynamic changes associated with the drug. Observations were made after a single dose (25 mg orally), and after short-term therapy (25 mg t.i.d. for 3 days). Captopril kinetics were as previously reported in normal subjects, with the exception that time to maximum concentration (tmax) to free captopril was slightly higher and the half-life (t1/2) was slightly shorter than in normal subjects. Total captopril t1/2 was longer than normal, suggesting cumulation. Urinary excretion was slower than normal. Differences between captopril kinetics on days 1 and 5 were that the tmax developed somewhat sooner, with a shorter t1/2 on day 5 and total captopril blood levels were higher on day 5 than on day 1. Urinary excretion was greater on day 5 than on day 1. Hemodynamic improvement after a single oral dose of captopril was significant and correlated with baseline plasma renin activity (PRA). The onset of converting-enzyme inhibition, as determined by PRA and hemodynamic improvement correlated with captopril blood levels.

Adult↗
PubMed1982

Prostacyclin in prostatic cancer: a better marker than bone scan or serum acid phosphatase?

Prostaglandins have been implicated in the development and spread of malignant tumours. Gas chromatography and mass spectrometry (GC-MS) analysis of prostaglandins in benign and malignant prostatic tissue showed that prostacyclin (PGI2), a prostanoid known to induce bone resorption, was the major component. PGI2 is hydrolysed to 6-oxo-PGF1 alpha. Plasma levels of 6-oxo-PGF1 alpha were measured as an index of PGI2 formation in patients with benign and malignant prostatic disease. The mean plasma 6-oxo- level in an age-matched control group was comparable to that of patients with benign prostatic hypertrophy. A significant elevation was found in patients with a TO carcinoma (P less than 0.05). Plasma 6-oxo- levels rise with advancing disease and the concentration varied with the degree of tumour differentiation. Plasma 6-oxo-levels were a more accurate monitor of disease progression than tartrate labile acid phosphatase in patients with M1 carcinoma. Persistently elevated levels were associated with a bad prognosis.

Acid Phosphatase↗
PubMed1982

Phaeochromocytomas of the bladder.

Phaeochromocytomas of the bladder are rare, only about 100 cases having been reported previously. Four adults with these lesions have been managed at Hammersmith Hospital in the past 10 years. Three patients had hypertension, together with syncopal attacks and/or headaches, induced by micturition. The fourth patient presented with haematuria. After control of blood pressure and localization of the tumours by various combinations of cystoscopy, intravenous urography, venous sampling, ultrasound, angiography and computerized coaxial tomography (CT scanning), 3 patients underwent partial cystectomy, and the fourth pelvic exenteration. Two patients were apparently cured of the disease, but 2 were not. One developed modal metastases and recurrence of hypertension after 18 months and one rapidly developed metastases in the lungs and elsewhere. Effective therapy probably requires a high index of suspicion in diagnosing the condition and possibly an aggressive surgical and radiotherapeutic policy.

Adult↗
PubMed1982

A variant alkaline phosphatase in renal cell carcinoma.

We report a case of renal cell carcinoma in which up to 32% of the abnormally increased alkaline phosphatase activity in serum was contributed by a variant alkaline phosphatase originating in the primary tumor and its secondary deposits. The variant enzyme was probably an altered form of normal renal alkaline phosphatase. The rest of the alkaline phosphatase activity in the serum was of hepatic origin, but no abnormality of the liver was discovered at autopsy.

Adenocarcinoma↗
PubMed1982

Steroid receptors in kidney tumours.

The presence of androgen and oestrogen receptors in normal and malignant human kidneys is reported. Characterization of these receptors was performed by glycerol gradient centrifugation and isoelectric focusing. Androgen receptors were detected in 40% of the tissues and its concentration was higher in the malignant kidneys. Oestrogen receptors were demonstrable in 8 out of 9 tumours, but only one out of 7 normal kidneys. The level of this receptor was extremely low.

Centrifugation, Density Gradient↗
PubMed1982

Relapsing idiopathic membranous nephropathy.

In a series of 60 patients with idiopathic membranous nephropathy (IMN), 8 subjects, aged 16-65 years at presentation, suffered spontaneous relapse of proteinuria after remissions of 25 months to 30 years. Renal biopsy was performed at the time of relapse in 5 cases and revealed histopathology identical to that of the original lesion. Eight courses of immunosuppressive therapy given to 6 patients did not affect either the appearance or duration of remission or relapse. No patient had a familial tendency to renal disease. Immunogenetic markers, HLA A, B and DR, did not distinguish those who relapsed from other patients with IMN. At the end of the study, 3 patients were in a second remission, one had died of myocardial infarction during relapse, 3 remained nephrotic and one had mild renal insufficiency but no proteinuria. As compared with the rest of the series the overall prognosis was not influenced by the relapses.

Adolescent↗