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Biomedical subjects

B Jackson

Publications and source records attributed to B Jackson.

At least 217 records · Page 12Linked to original sources
PubMed1986

The use of alcoholic paper wipes for routine hand cleansing: results of trials in two hospitals.

The use of alcoholic paper hand wipes by nursing staff was assessed in two trials. No significant changes in total viable counts from finger imprint samples were observed when wipes were used, but some decrease in samples positive for Enterobacteriaceae and Staphylococcus aureus was recorded. The wipes were found to be pleasant and convenient to use. It is concluded that wipes are an acceptable alternative to soap and water for routine hand cleansing.

Bacteria↗
PubMed1986

Angiotensin-converting enzyme (ACE) measurement in human serum using radioinhibitor ligand binding.

MK351A, a tyrosyl analogue of enalaprilic acid (MK422) is a potent inhibitor of angiotensin-converting enzyme (ACE). MK351A was radioiodinated with 125I and used to develop a radio inhibitor binding assay for human serum ACE. 125I MK351A associated rapidly and reversibly with human serum ACE (T 1/2 = 1/2 h). Bound 125I MK351A was displaced by an excess of cold MK351A, to give non-specific binding of less than 1%. Scatchard analysis of binding was linear (r = -0.99, n = 6, p less than 0.001), indicating a single class of binding site. ACE was estimated in serum from normal patients and patients with sarcoid by the radio inhibitor binding assay and by enzyme kinetic assay using Hip-His-Leu as substrate. The two methods for ACE estimation correlated closely (r = 0.87, n = 82, p less than 0.001). The radio inhibitor binding assay for human serum ACE is a simple, sensitive and specific assay which utilizes novel assay methodology.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1986

Angiotensin converting enzyme (ACE), characterization by 125I-MK351A binding studies of plasma and tissue ACE during variation of salt status in the rat.

Angiotensin converting enzyme (ACE) was measured in rat plasma and tissues by analysis of the binding of the radio-inhibitor 125I-MK351A, a tyrosyl derivative of enalaprilic acid. Labelled 125I-MK351A bound to plasma and tissue ACE preparations and was displaced in a concentration-related manner by MK351A. Scatchard analysis yielded a single line from which MK351A binding sites/mg protein and MK351A dissociation constant were calculated. Tissue and plasma ACE from Sprague Dawley rats was studied over a wide range of sodium intakes (low salt, 0.026 +/- 0.012 mmol/24 h; normal salt, 0.58 +/- 0.09 mmol/24 h; and high salt, 10.4 +/- 1.3 mmol/24 h) and during high salt and DOCA treatment. Across the range of sodium states studied there were no consistent changes in plasma, lung, aorta, brain, epididymis or kidney MK351A binding sites/mg protein, or equilibrium dissociation constant. Calculated MK351A binding sites (nmol/mg protein) were 1.64 +/- 0.14 in lung, 0.47 +/- 0.04 in aorta, 0.44 +/- 0.05 in epididymis, 0.18 +/- 0.01 in brain and 0.053 +/- 0.004 in kidney preparations (n = 24 in each group) reflecting reported ACE enzymatic activity in these tissues. Equilibrium dissociation constant KD was uniform within each tissue, but varied between organs. The KD (mol/l X 10(-12)) was 50 +/- 2 in aorta, 57 +/- 2 in lung, 58 +/- 2 in epididymis, 61 +/- 3 in brain, 62 +/- 2 in plasma and 84 +/- 3 in kidney (n = 24 in each group).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1986

Evaluation of angiotensin converting enzyme (ACE) in the pharmacokinetics and pharmacodynamics of ACE inhibitors.

The increasing number of angiotensin converting enzyme (ACE) inhibitors means that compounds with different enzyme kinetics, pharmacokinetics, bioavailability, and pharmacodynamics will appear. They will, however, all inhibit ACE, and their hypotensive effect will be a consequence of this action. Enalapril (MK-421) is an esterified prodrug, which in man is converted by the liver to the bioactive potent ACE inhibitor enalaprilate (enalaprilic acid, MK-422). This probably accounts for the slower plasma appearance of MK-422 and the longer duration of action of enalapril. The clinical significance of deesterification by the liver needs further study but minor abnormalities of liver function, such as occur in congestive heart failure, do not affect the rate of deesterification and hence the plasma enalaprilat levels. A close relationship between the plasma drug level, degree of ACE inhibition, and the hormonal and hypotensive effect can be demonstrated after both acute and chronic enalapril administration to hypertensive patients. Chronic therapy with enalapril leads to induction of ACE but in humans this is not sufficient to lead to resistance or tolerance to the drug. Enalapril offers an exciting new approach to the treatment of hypertension with some distinct advantages over conventional antihypertensive therapy.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1986

Preservation of renal function in the rat remnant kidney model of chronic renal failure by blood pressure reduction.

The remnant kidney model of chronic renal failure was established in female Sprague-Dawley rats subjected to surgical removal of the right kidney and segmental infarction of seven-eighths of the left kidney. Plasma creatinine (mumol/l) rose from 65 (s.e.m. = 16, n = 18) to 153 (s.e.m. = 27, t-test, P less than 0.001, d.f. = 17) over 6 weeks. Histological glomerulosclerotic lesions were present from 2 weeks and prominent by 6 weeks post-surgery. Rats were treated with enalapril (5 mg/kg per day, n = 11) or felodipine (30 mg/kg per day, n = 13) from 1 week post-surgery, and their course compared to untreated rats (n = 18). Blood pressure (mmHg) was lowered by both treatments. Six weeks post-nephrectomy, systolic blood pressure in the untreated group was 176 (s.e.m. = 7, n = 18), enalapril group 122 (s.e.m. = 5, t-test, P less than 0.001, d.f. = 27), and felodipine group 128 (s.e.m. = 3, t-test, P less than 0.001, d.f. = 29). Plasma creatinine (mumol/l) was lower in the enalapril group (110, s.e.m. = 8, t-test, P less than 0.05, d.f. = 27) but not the felodipine group (173, s.e.m. = 19, t-test, n.s.) 6 weeks after subtotal nephrectomy compared to the untreated group (153, s.e.m. = 27). Glomerulosclerosis (blinded histological score) was reduced with enalapril treatment (1.93, s.e.m. = 0.03, t-test, P less than 0.05, d.f. = 27) but not felodipine treatment (2.15, s.e.m. = 0.04, c.f. untreated 2.36, s.e.m. = 0.12, t-test, n.s.). Urinary protein excretion (mg/24 h) was 84 (s.e.m. = 22, n = 13) in untreated rats, 15 (s.e.m. = 3, t-test, P less than 0.001, d.f. = 22) in enalapril-treated rats and 221 (s.e.m. = 35, n = 10) with felodipine treatment. Functional and structural damage in the rat remnant kidney model of chronic renal failure was ameliorated by treatment with enalapril but not by treatment with felodipine.

Animals↗
PubMed1986

Characterization of angiotensin converting enzyme from rat tissue by radio-inhibitor binding studies.

Angiotensin converting enzyme (ACE) derived from rat lung, aorta, epididymus, brain, kidney and plasma was characterized by radio-inhibitor (125I-MK351A) binding studies. Under optimal binding conditions at equilibrium 125I-MK351A bound to ACE was displaced from ACE in a concentration related manner by unlabelled MK351A. MK351A binding site concentration for each tissue and equilibrium dissociation constant (KD) was estimated by Scatchard analysis of binding data. Binding sites/mg protein was greatest in lung and least in brain. The KD for kidney ACE was significantly higher than that of lung, aorta, epididymus or brain ACE (P less than 0.005; t-test, d.f. = 10). 125I-MK351A bound to ACE prepared from lung and kidney was displaced in a concentration dependent manner by SQ20881, SQ14225, MK422, and Ro31-3113-000. Concentration of ACE inhibitor required to displace 50% of bound 125I-MK351A (DD50) was consistently higher for kidney-derived ACE than lung-derived ACE. The differences in radio-inhibitor binding characteristics of ACE from different rat tissues suggests that the enzyme active site may not be identical in all organs.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1986

Primary aldosteronism due to a malignant ovarian tumour.

The case of a woman with autonomous aldosteronism, hypertension, and malignant ovarian tumour is reported. Hormone studies revealed high plasma aldosterone levels, and low plasma renin concentration. Following surgical removal of a malignant sex cord stromal tumour, the hyperaldosteronism regressed, and the hypertension improved. Subsequently the tumour recurred, as did hyperaldosteronism.

Aldosterone↗
PubMed1986

Renovascular hypertension: treatment with the oral angiotensin-converting enzyme inhibitor enalapril.

Sixteen patients with an established diagnosis of renovascular hypertension were entered in an open study of enalapril (MK421), an oral angiotensin-converting enzyme (ACE) inhibitor, for treatment of their hypertension. Initial blood pressure was 178.9 +/- 6.3/106.2 +/- 3.1 mm Hg during conventional therapy on a median of 3 different antihypertensive agents. All antihypertensive therapy was ceased and the patients admitted to hospital. Following introduction of enalapril, blood pressure fell to 161.5 +/- 6.9/90.6 +/- 4.1 mm Hg at 24 h (p less than 0.01 systolic and diastolic). Blood pressure control (diastolic blood pressure, phase V, less than 95 mm Hg) was achieved with monotherapy in 7 patients and in a further 5 patients with addition of a diuretic. Renal function was compromised in 4 patients, requiring cessation of enalapril in 2 instances. Enalapril is an oral ACE inhibitor useful in the treatment of renovascular hypertension. Close monitoring of renal function is necessary during the introduction of enalapril therapy in patients with renovascular hypertension.

Adult↗
PubMed1986

Platelet function in hypercholesterolemics before and after hypolipidemic drug therapy.

Platelet function parameters were studied in type II hyperlipoproteinemics in relation to baseline and drug-induced changes in serum cholesterol levels. There were no significant differences between 28 type II hyperlipoproteinemics and 19 normal subjects in baseline values for platelet aggregation, thromboxane generation, sensitivity to prostacyclin, plasma platelet factor 4 or beta-thromboglobulin. Eleven of the hyperlipoproteinemic patients were treated with a combination of the cholesterol-lowering drugs probucol and colestipol. The drug treatment resulted in statistically significant lowering of serum total and low-density lipoprotein (LDL)-cholesterol levels (30% reduction of mean LDL-cholesterol, p less than 0.01); however, there was no significant change in any of the platelet function parameters after the drug treatment compared with placebo. These results provide evidence against a relationship between serum cholesterol levels and in vitro platelet function.

Adult↗
PubMed1986

Differential renal function during angiotensin converting enzyme inhibition in renovascular hypertension.

Renal function was measured sequentially in 32 patients with proven renovascular hypertension who were treated with the oral angiotensin converting enzyme inhibitor captopril. Renal function was assessed by serial measurement of serum creatinine. Six patients showed acute rises in serum creatinine concentration compatible with acute renal failure. Acute renal failure was confined to those patients with stenosis to a solitary kidney (transplant or native, occurring in 3 of 8 patients) or bilateral renal artery stenosis (occurring in 3 of 13 patients). No rise in serum creatinine concentration was observed in 11 patients with unilateral renal artery stenosis during long-term angiotensin converting enzyme inhibitor therapy. Acute renal failure during angiotensin converting enzyme inhibitor therapy was not related to the degree of blood pressure fall or the plasma angiotensin II level. Eleven patients with renovascular hypertension were followed prospectively with estimation of renal function by 99mTc-diethylenetriaminepentaacetic acid (DTPA) clearance (determined by computer analysis of scintillation camera renography). In six patients with unilateral renal artery stenosis, total 99mTc-DTPA clearance and serum creatinine level remained constant following angiotensin converting enzyme inhibitor therapy, while in five patients with bilateral renal artery stenosis 99mTc-DTPA clearance fell from 40 +/- 9 to 27 +/- 5 ml/min (p less than 0.05). Split renal function studies revealed that 99mTc-DTPA clearance fell in most kidneys with stenosed arteries during angiotensin converting enzyme inhibition, including the stenosed kidney from patients with unilateral renal artery stenosis (16 stenosed kidneys studied; change in Tc-DTPA clearance, -7.5 +/- 2.7 ml/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1986

Methods to assess relative reliability of diet records: minimum records for monitoring lipid and caloric intake.

A total of 252 diet records of 18 outpatients attending a lipid clinic were analyzed by a computer-assisted method to determine the minimum number of daily diet records that would be reliable for monitoring dietary adherence. Each subject recorded food intake in special diaries for 14 consecutive days between two clinic visits. All possible randomly selected combinations of 3, 4, 5, 7, 9, and 11 consecutive days of records in the 14-day period were analyzed for calories and lipids. Sets of records were said to be within a 95% confidence interval when the information yielded on any parameter differed by 5% or less from the mean values for the entire 14 days' records. All sets of records for 7, 9, and 11 days were in the 95% confidence range; therefore, 7 consecutive days of food recording were considered the minimum requirement for a 95% confidence limit. Out of 11 possible combinations of 4 consecutive day-sets of records, all but 3 sets were within 95% confidence limits. Consequently, 4 consecutive days of records were deemed acceptable as a reasonable compromise for minimal, reliable monitoring of diet compliance in outpatients for the nutrients studied.

Adult↗