Effect of trial therapy on subsequent therapy. A review of patients with hypertension who have completed a pharmacological intervention study.

After a clinical trial was completed in which two commonly used antihypertensive agents (prazosin and propranolol) were compared, 20 previously untreated men with moderate, asymptomatic, essential hypertension returned to the care of their general practitioners. Twelve months later 17 patients who were still attending the same doctor demonstrated improved blood pressure control with a decrease in their lying diastolic blood pressure from 96 +/- 2 mmHg to 91 +/- 2 mmHg (P less than 0.01).

Effect of indomethacin on urine concentration and dilution in the rat.

The precise role of prostaglandins in modulating urine concentration and dilution is unclear. Evidence in vitro has recently cast doubt on the accepted theory that renal prostaglandins inhibit the hydro-osmotic effect of vasopressin. Urine clearance studies were performed on indomethacin treated (prostaglandin deficient) and control anaesthetized water diuretic rats both before and during the addition of vasopressin in maximal (10 m-units) and supramaximal (100 m-units) concentrations.

Effect of an optimum dialysis fluid calcium concentration on calcium mass transfer during maintenance hemodialysis.

The effect of an optimum dialysis fluid calcium concentration (1.625 mmol/l) on calcium mass transfer from dialysis fluid to patient was assessed in patients on routine hemodialysis. While there was a mean body gain of only 3.

Mechanism of action of natriuretic fraction of urine.

The nature of calcium dependence of natriuretic fraction (NF)-induced contractions in the rat smooth muscle anococcygeus and a possible correlation between the effect of NF on sodium transport and its natriuretic potency was investigated. NF and noradrenaline-induced contractions were partially dependent on external calcium concentration. Ouabain and potassium (K) free solution (KoPSS)-induced contractions were totally dependent on external calcium and were more effectively inhibited by calcium antagonists than those of NF and noradrenaline suggesting pharmacomechanical coupling as the mode of calcium dependence of NF.

Adjunctive effect of salt restriction on antihypertensive efficacy.

The effect of dietary salt restriction on blood pressure was measured in patients with moderate hypertension receiving antihypertensive medication. Patients were studied during a randomly allocated 6 week period of moderate dietary salt restriction and during a 6 week period of normal diet. Twenty-four of twenty-eight patients achieved a reduction of salt excretion exceeding 20%.

Effect of dietary sodium restriction on patients receiving antihypertensive medication.

Twenty-four patients receiving medication for moderate to severe hypertension were studied during a six week normal diet and a six week low sodium period. Mean urinary sodium excretion was reduced from 169 +/- 13 to 92 +/- 7 mmol/24 hour yet with the exception of a small reduction in the mean erect systolic blood pressure 140.7 +/- 2.

Evaluating patients' satisfaction with medical students' interviewing skills.

Two studies are reported which examine the use and credibility of patients' reports of medical students' clinical interviewing skills. In the first study patients' high satisfaction via a standard rating form tended to match clinicians' assessment of second-year students' history-taking and physical examination skills. A second study used pre-defined 'ideal' and 'not-ideal' bedside roles by a small group of fourth-year students to examine how perceptive or tolerant hospital inpatients are about clinical interviews, whether this effect is sex-linked, and consequently how useful direct and indirect information obtained from patients is in training medical students' interviewing skills.

Effect of calcitonin on hemodialysis patients with hypercalcemia and renal osteodystrophy.

Because calcitonin administration has been shown to decrease the serum calcium level in certain hypercalcemic conditions, 10 patients on maintenance dialysis with renal osteodystrophy and persistent hypercalcemia were treated with salmon calcitonin for 3 months. While plasma calcium concentrations were reduced by calcitonin therapy in four patients, therapy was ceased in two patients due to a worsening of their hypercalcemia, although in another two patients the initial worsening of the hypercalcemia settled with continued therapy. No significant changes in calcium levels occurred in the remaining two patients.

Lithium administration and urinary electrolyte excretion in the rat.

The effect of lithium administration on urine eletrolyte excretion is controversial with reports of increased, unaltered and reduced excretion rates of sodium, potassium, calcium, magnesium and inorganic phosphate. Therefore rats treated with daily intraperitoneal lithium chloride for 3 weeks were studied and were found to have marked fluctuations in electrolyte excretion when compared to untreated rats. Although lithium-treated rats were always polyuric, urinary sodium, potassium and calcium excretion was significantly elevated immediately following intraperitoneal lithium but their excretion rates then returned towards normal.

Effect of calcitonin on urine concentration in the rat.

Because mammalian distal nephron segments with both calcitonin- and antidiuretic hormone- (ADH) sensitive adenylate cyclase activity have been described, in vivo and in vitro experiments were performed to study the effect of calcitonin on rat distal nephron water permeability. Calcitonin 1 and 0.1 U/ml, but not 0.

The mechanism of polyuria in rats pretreated with lithium studies by in vitro microperfusion.

The collecting ducts in papillae taken from normal rats have a measurable increase in diffusional tritiated water (THO) permeability with ADH 5 mu unit/ml and this increase is maximal with antidiuretic hormone (ADH) 100 mu unit/ml added to media. The presence of plasma from rats pretreated with lithium to make them polyuric inhibited the response to ADH. The lowest concentration of ADH that caused a measurable increase in diffusional water permeability was 50 mu unit/ml and the increase was maximal with ADH 2000 mu unit/ml.

Effect of differing concentrations of parathyroid hormone on rat renal electrolyte excretion.

Urinary clearance studies were performed on acutely thyroparathyroidectomized rats to study the effect of a range of parathyroid hormone (PTH) concentrations on renal electrolyte transport. PTH 0.1 U, prime and per hour, significantly increased the plasma calcium concentration, yet fractional calcium excretion was increased by 47.

The influence of cyclic nucleotides on DNA synthesis in skin.

Total saline-soluble protein, total DNA, and 3H-thymidine labelling of DNA were measured in cultured guinea-pig skin during a 3-day incubation period. An early rise in total soluble protein and a fall in total DNA indicated loss of the cells damaged in cutting the skin samples. Samples incubated with dibutyryl cyclic adenosine monophosphate (db cAMP) showed an early stimulation of DNA synthesis.

Relationship between plasma and cellular potassium content during potassium repletion.

The simultaneous effect of two weeks of potassium repletion therapy on the plasma concentration and total body content of potassium was assessed in seven patients with hypokalaemia. Glomerular filtration rate, renal plasma flow, and maximal urinary concentration were also measured both before and after therapy with potassium chloride. While the plasma potassium concentration quickly returned to normal, total body content of potassium remained depressed, emphasizing the unreliability of the plasma potassium concentration as an indicator of total body potassium status.