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Biomedical subjects

B Jackson

Publications and source records attributed to B Jackson.

At least 253 records · Page 14Linked to original sources
PubMed1984

An automatic monitoring system for measuring handwashing frequency in hospital wards.

A handwash monitoring system is described which enables accurate measurements to be taken of the frequency of handwashing by nursing and medical staff during the course of their duties. Preliminary studies have demonstrated it can record handwashing frequency with 93 per cent accuracy and, during preliminary ward trials, the measured handwashing frequency was 5-10 washes per nurse per shift. This was far less than the nurses' claimed handwashing frequency.

Cross Infection↗
PubMed1984

Hypertension and unilateral hydronephrosis.

We report 2 cases of hypertension associated with unilateral hydronephrosis. Lateralization of renal vein renins and exaggerated hyperreninemia following captopril suggested renin-mediated hypertension in 1 case, which responded well to nephrectomy.

Adult↗
PubMed1984

Serum lipids in normo- and hyperlipidemics after methyldopa and propranolol.

We report on serum lipoprotein changes after antihypertensive therapy in nine subjects with type II hyperlipoproteinemia and eight subjects with normolipidemia. They received placebo for 6 wk, followed by random order crossover between methyldopa and propranolol for 6 mo. Physical activity, diet, and other drugs were monitored for constancy. No other antihypertensive drugs were used. Doses required for normalization of blood pressure ranged between 40 to 360 mg/day for propranolol and 500 to 2500 mg/day for methyldopa. Mean blood pressure was equally lowered to normal by both drugs. Triglyceride levels increased after propranolol and after methyldopa. Subjects with normocholesterolemia developed higher serum triglyceride levels after each drug, whereas such a change did not occur in patients with hypercholesterolemia. Low-density lipoprotein cholesterol levels were reduced by methyldopa only in patients with baseline hypercholesterolemia. There was no correlation between lipoprotein level changes, dose required of either drug, or propranolol blood levels. The baseline lipoprotein metabolism disorder appears more likely to determine the type of changes in serum lipoprotein levels after these antihypertensive drugs.

Adult↗
PubMed1984

Mechanism for hypotensive action of angiotensin converting enzyme inhibitors.

The mechanism(s) for the hypotensive effect of Angiotensin Converting Enzyme (ACE) inhibitors remains elusive. This is because of the multiplicity of the biological actions of angiotensin, the dual role of ACE and the ability of the inhibitors to induce the enzyme. After a single dose of enalapril (MK421), a new ACE inhibitor, in patients with essential hypertension a close linear relationship between the plasma level of enalaprilic acid (MK422) and the degree of ACE inhibition could be demonstrated. Furthermore the degree of ACE inhibition was linearly related to the hormonal changes and to the fall in blood pressure. After chronic administration of enalapril the plasma levels of MK422 were found to be dose dependent. As in the acute study there was also a linear relationship between the plasma level of MK422 and the degree of ACE inhibition. However, the plasma enalaprilic acid level-ACE inhibition dose response curve after chronic administration was shifted to the right, compared to the dose response curve after acute administration suggesting that ACE had been induced during chronic administration of enalapril in humans. There were direct linear relationships between both the degree of ACE inhibition the plasma and enalaprilic acid (MK422) level to the fall in mean arterial pressure. These results suggest that regardless of the final mechanism for the hypotensive action of ACE inhibitors it is a consequence of their inhibition of the enzyme.

Antihypertensive Agents↗
PubMed1984

Probucol with colestipol in the treatment of hypercholesterolemia.

The effects of therapy with 1 g of probucol and 20 g of colestipol were compared with those of the drugs used singly on 47 patients with hypercholesterolemia in a double-blind, double-placebo, diet-controlled, crossover trial that lasted 18 months. The probucol and colestipol combination, but neither drug alone, reduced mean serum low-density-lipoprotein (LDL)-cholesterol levels from 242 +/- 51 (SE) mg/dL during the diet and placebo phase to 171 +/- 41 mg/dL. Probucol significantly lowered high-density-lipoprotein (HDL)-cholesterol levels and increased LDL:HDL-cholesterol ratios. Combination therapy did not change LDL:HDL cholesterol ratios. Probucol alone or in combination reduced very-low-density-lipoprotein cholesterol levels, despite concomitant elevations of serum triglyceride levels caused by colestipol in the combination protocol. Gastrointestinal side effects of single drugs were abolished when drugs were used in combination. Compared with the values in the diet-placebo phase, LDL-cholesterol levels were reduced by more than 20% in 81% of patients, by more than 30% in 49%, and by more than 40% in 17%. This drug combination proved to be safer and have greater hypocholesterolemic effects in more patients than other marketed drug treatments.

Adult↗
PubMed1984

Effect of dietary sodium on angiotensin-converting enzyme (ACE) inhibition and the acute hypotensive effect of enalapril (MK-421) in essential hypertension.

The hormonal and hypotensive effects of a single oral 10 mg dose of enalapril (MK-421), were assessed by a double-blind randomized trial in 12 subjects with essential hypertension, during a 100 and 40 mmol/day sodium intake. Peak serum MK-421 appeared 1 h following oral dosage. The bioactive conversion product of MK-421 (the parent diacid MK-422) appeared later, was maximal 4 h following dosage, and was still detectable 24 and 32 h later. Serum angiotensin-converting enzyme (ACE) activity was inhibited maximally at 4 h (by 57 +/- 4% of control activity) and had a similar time course to the serum MK-422 level. Plasma angiotensin II and aldosterone fell during ACE inhibition, but no change in bradykinin was detected. Reciprocal rises in plasma renin and angiotensin I occurred with a similar time course to ACE inhibition. Sodium depletion did not alter drug levels, basal serum ACE nor the time course of its inhibition. The initial blood pressure was however significantly lower when the subjects had been on the 40 mmol/day sodium diet. Blood pressure fell in all subjects and the fall was maximal 4-8 h following MK-421. There was a close correlation between plasma drug level, ACE inhibition and the hypotensive effect. These results suggest that regardless of the final mechanism for the antihypertensive action of MK-421 it is a consequence of its inhibition of ACE.

Adult↗
PubMed1983

The effect of variable fat diets and cholesterol-lowering drugs on Antithrombin III levels in hyperlipoproteinemic and normal subjects.

Functional and immunological Antithrombin III (AT III) levels were studied in normal and hyperlipoproteinemic subjects undergoing crossover therapeutic trials of either diets or hypocholesterolemic drugs. The diet trial subjects, 7 hyperlipoproteinemics and 15 normals, were randomly assigned to crossover between a high saturated fat diet (P/S ratio 1:8) and a high polyunsaturated fat diet (P/S ratio 4:1) for periods of 6-8 weeks, preceded by a baseline period on regular American diet (P/S ratio 1:1). For the drug trials, 33 type II A or B hyperlipoproteinemics were treated in random and double-blind fashion with Colestipol (20 gm/day) or both, for periods of 3 months, preceded by a double placebo period. Mean low density lipoprotein cholesterol levels were significantly different (p less than 0.001) between high saturated and high polyunsaturated fat diets (157 +/- 37 mg/dl vs 137 +/- 31 mg/dl respectively, mean +/- S.D.) and between placebo and drug treatment periods (226 +/- 51 mg/dl vs 183 +/- 44 mg/dl respectively, mean + S.D.). There was no difference in basal functional or immunological AT III levels between normal and hyperlipoproteinemics. AT III levels did not correlate significantly with cholesterol or triglyceride levels and remained unchanged despite significant reductions in serum cholesterol related to the diet and drug therapy. There appears to be no significant association between baseline or post treatment serum cholesterol levels and functional or immunological AT III. Thus, changes in AT III are unlikely to play a role in the link between hypercholesterolemia and thrombosis.

Adult↗
PubMed1983

Post traumatic renal hypertension.

Two cases of hypertension following renal trauma are reported. In both cases, blood pressure was controlled with captopril, an angiotensin converting enzyme inhibitor. Mechanisms of hypertension following renal trauma are reviewed and the place of medical or surgical management discussed.

Adult↗
PubMed1983

The role of prostaglandins in gentamicin-induced nephrotoxicity in the dog.

The effects of chronic gentamicin administration on renal function was studied in dogs receiving 4 mg/kg i.m. of gentamicin b.i.d. for 28 days. Administration of gentamicin resulted in a bimodal change in renal function. A decrease in urine osmolality was first noted on day 6 and declined progressively throughout the study. This decrease in urinary concentrating ability was preceded by a steady rise in urinary prostaglandin E2 (PGE) excretion and followed by a rise in plasma renin activity (PRA). Prior to an increase in azotemia, urinary PGE decreased precipitously while PRA continued to rise throughout the remainder of the study. The precipitous decrease in GFR was accompanied by a significant increase in FENa to seven times control. These studies suggest a dual effect of chronic gentamicin administration on renal function: (1) an early effect manifested by stimulation of urinary prostaglandin production with a concomitant loss of urinary concentrating ability and mild prerenal azotemia, and (2) a late effect, preceded by a decrease in urinary prostaglandin excretion while PRA continues to increase, and manifested by increase fractional excretion of sodium and progressive azotemia.

Acute Kidney Injury↗
PubMed1983

Pharmacology of agents acting on the renin-angiotensin system.

The renin-angiotensin system is the most important hormonal system in the control of blood pressure. It can be blocked at several steps in its reaction pathway. Angiotensin-converting enzyme, or kininase II, is responsible for catalysing the formation of vasoconstrictor angiotensin II as well as for the breakdown of the vasodilator bradykinin. With the advent of specific orally active angiotensin-converting enzyme inhibitors (captopril and enalapril) a practical and effective means of blocking angiotensin formation is now clinically available. ACE inhibitors are effective long-term therapy in patients with essential hypertension. They are particularly useful in the treatment of severe accelerated drug-resistant hypertension and renovascular hypertension, and the agents of choice for afterload reduction in severe congestive cardiac failure. They have several pharmacological advantages, important in anaesthetic practice, over other hypotensive agents. They have no central nervous or autonomic nervous system effects. Thus, patients being treated with ACE inhibitors retain normal sympathetic cardiovascular responses.

Angiotensin-Converting Enzyme Inhibitors↗