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Biomedical subjects

J R Paterson

Publications and source records attributed to J R Paterson.

18 recordsLinked to original sources

Probucol reduces plasma lipid peroxides in man.

Although primarily used as a lipid lowering drug, probucol also possesses anti-oxidant activity and has been shown in animal models to inhibit or delay the progression of atherosclerosis. It has been suggested that this anti-atherosclerotic effect may occur through inhibition of free radical oxidation of low density lipoprotein. The aim of this study was to investigate the effects of probucol on free radical activity in hyperlipidaemic patients. Plasma lipid peroxides were measured before probucol treatment, at 4 and 12 weeks treatment and then 4 weeks after stopping probucol. Lipid peroxide concentrations were significantly reduced during and 4 weeks after stopping treatment with probucol, when compared with baseline values. There were no changes in plasma vitamin E concentrations. The results of this study indicate that probucol reduces lipid peroxidation in patients, an effect which may occur through a free radical scavenging action.

Adult

Coronary venous lipid peroxide concentrations after coronary angioplasty: correlation with biochemical and electrocardiographic evidence of myocardial ischaemia.

BACKGROUND: Raised lipid peroxide concentrations in coronary venous plasma have been reported after coronary angioplasty in humans. This may reflect increased free radical activity after myocardial ischaemia and reperfusion. If so, it may be possible to correlate lipid peroxide concentrations with the degree of myocardial ischaemia produced during angioplasty. METHODS: 15 patients (age range 42-70; 12 men) with stable angina pectoris undergoing angioplasty of a proximal left anterior descending coronary artery stenosis were studied. Plasma lipid peroxide and lactate concentrations were measured in sequential blood samples taken from the great cardiac vein before and immediately after one to five serial 60 second balloon inflations. The maximum ST segment shift during each balloon inflation was also measured. RESULTS: Lipid peroxide concentrations in coronary venous plasma were raised from pre-angioplasty values by more than 2 SDs of the relevant measurement error after 27 out of 46 (59%) balloon inflations. Lactate concentrations were raised after 43 out of 46 (93%) balloon inflations. No significant difference was found between the peak percentage change of either lipid peroxide or lactate concentrations after any of the first three serial inflations. The maximum ST segment shift after each of the first three serial inflations was also similar. Coronary venous lactate concentrations after balloon inflation correlated positively with the maximum ST segment shift, but did not correlate with lipid peroxide concentrations. CONCLUSIONS: Raised lipid peroxide concentrations in coronary venous plasma can be detected in humans after balloon angioplasty. There is no positive correlation between lipid peroxide concentrations in coronary venous plasma after angioplasty and the degree of preceding myocardial ischaemia as assessed by either ST segment shift or lactate production. These indices showed that one to three serial 60 second balloon inflations each produce a similar degree of myocardial ischaemia. The origin of the raised lipid peroxide concentrations in coronary venous plasma after angioplasty remains unknown.

Adult

Free radical activity and hemostatic factors in NIDDM patients with and without microalbuminuria.

In non-insulin-dependent diabetes mellitus (NIDDM) patients, microalbuminuria predicts early mortality, predominantly from cardiovascular disease. Increased free radical activity and abnormalities in hemostasis have been implicated in the development of vascular disease. Therefore, we measured markers of free radical activity (nonperoxide-conjugated diene isomer of linoleic acid [PL-9,11-LA'] and lipid peroxides expressed as malondialdehyde [MDA]) along with the hemostatic variables: fibrinogen, von Willebrand factor (vWf), plasminogen activator inhibitor (PAI-1), tissue plasminogen activator (t-PA), and plasmin activity (B beta 15-42) in 24 NIDDM patients (12 patients with microalbuminuria and 12 without microalbuminuria) and in 12 age-matched control subjects. There were no differences in linoleic acid (PL-9,12-LA) concentrations between the three groups. PL-9,11-LA' was elevated in the microalbuminuric patients compared with control subjects (P less than 0.05), but there was no difference between the two diabetic groups. MDA was elevated in the microalbuminuric diabetic patients compared with those patients without microalbuminuria (P less than 0.05) and control subjects (P less than 0.001). MDA was also increased in the patients without microalbuminuria compared with control subjects (P less than 0.01). Except for B beta 15-42, all the hemostatic variables were increased (P less than 0.05) in the diabetic patients compared with control subjects. The microalbuminuric diabetic patients had further increases in vWf (P less than 0.03) and t-PA (P less than 0.03) compared with patients with microalbuminuria. Our study suggests that there is an increase in free radical activity and abnormalities in hemostatic variables favoring a hypercoagulable state in NIDDM, especially in those with microalbuminuria.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Screening for hyperlipidaemia in diabetes mellitus. Relationship to glycaemic control.

Diabetic patients have an increased risk of developing cardiovascular disease which, in part, may be due to lipid abnormalities. Our aim was to establish from an initial screening programme what proportion of diabetic patients attending a routine diabetic outpatient clinic had hyperlipidaemia despite having good or acceptable glycaemic control. We screened 299 randomly selected diabetic patients to assess the prevalence of hyperlipidaemia and its relationship to glycaemic control. Twenty-eight per cent had hyperlipidaemia (defined as cholesterol greater than 6.5 mmol/L and/or non-fasting triglycerides greater than 3 mmol/L). Of these hyperlipidaemic patients, 71% had good or acceptable glycaemic control as defined by a glycated haemoglobin value of less than 10%. Approximately 40% of type 2 diabetic patients had body mass index values outside recommended targets indicating the potential of weight reduction in this group as a treatment modality. Our results indicate that the majority of hyperlipidaemic diabetic patients had good or acceptable glycaemic control, and as such these patients are potential candidates for specific lipid lowering therapy.

Adolescent

Medical training in clinical biochemistry (chemical pathology) in Scotland 1985-1989.

A questionnaire was sent to 35 doctors who were believed to have trained in clinical biochemistry in Scotland between 1 January 1985 and 31 December 1989. Thirty replies were received from 23 individuals who were still employed in the specialty (including seven consultants and nine senior registrars) and from seven individuals who had left. Twenty considered that training within the laboratories in which they were employed had not been satisfactory. The main emphasis of training was directed towards reporting duties, clinical liaison, research, teaching and outpatient clinics. Little training was provided for the development of analytical experience, personnel selection and laboratory management. Those surveyed identified poor training in laboratory management as the main aspect of training which required improvement.

Adult

Delayed diagnosis of Addison's disease.

Addison's disease may be difficult to diagnose because of the non-specificity of the most frequently occurring symptoms. Hyponatraemia, hyperkalaemia, and uraemia are commonly detected in sera from patients with Addison's disease. We report two patients in whom the diagnosis was delayed, despite typical biochemical abnormalities in their sera during initial presentation. A computer search of 4 weeks of biochemical data (9862 requests for electrolytes) indicated that these typical biochemical abnormalities occurred commonly in other patients, increasing the difficulty of the clinical biochemist in detecting Addison's disease. Awareness of this problem, in combination with adequate clinical information, should enable the clinical biochemist to assist in the earlier diagnosis of Addison's disease.

Addison Disease

The effects of intradermal bradykinin are potentiated by angiotensin converting enzyme inhibitors in hypertensive patients.

1. To test the hypothesis that angiotensin converting enzyme (ACE) inhibitors potentiate the tissue effects of bradykinin, the thickness of weals produced by intradermal injections of bradykinin was measured in 17 hypertensive subjects whose antihypertensive regimen included an ACE inhibitor, and in 12 whose treatment did not. 2. Weal thickness increased linearly with the logarithm of the bradykinin dose in both groups (P less than 0.0001). 3. The patients receiving ACE inhibitors showed a mean response of 1.18 +/- 0.08 mm (mean +/- s.e. mean), compared with a mean response of 0.75 +/- 0.08 mm for patients not receiving an ACE inhibitor (P = 0.002). Mean weal response (1.08 +/- 0.9 mm) was not significantly different in patients taking captopril (n = 11) compared with that (1.29 +/- 0.12 mm) in patients taking enalapril (n = 9). 4. Facial flushing during the experiment occurred in six patients taking ACE inhibitors but none who were not. 5. Dermal responses to bradykinin are enhanced in patients taking ACE inhibitors as routine antihypertensive therapy. This study supports the hypothesis that bradykinin may be responsible for some of the adverse effects of these drugs.

Adult

On-call service: the role of chemical pathologists.

The workload of the chemical pathology advisory on-call service was investigated. Over three years 317 calls were recorded, giving a mean of nine calls a month. Seasonal variation in the number of calls was observed, with an increase in calls during December, January, and February. Requests for the arrangement of analysis accounted for 231 calls, while there were 98 requests for advice. Authorization of a request for analysis was the outcome of 156 calls. Advice with respect to investigation, treatment, or interpretation of results was offered during 173 calls. The acute medical and surgical wards, the accident and emergency department, renal unit and intensive care unit accounted for 198 of the calls. The two analyses most frequently requested, through the advisory on-call service, were serum digoxin and blood ethanol, with 51 and 33 requests, respectively. The "acute" wards and accident and emergency department had the greatest request rate, accounting for 35 of the requests for digoxin and 26 of the requests for blood ethanol. The acute care areas were responsible for the major part of the workload, and a clinical requirement for the services of chemical pathologists out of hours, was observed.

Blood Chemical Analysis

Drug therapy in patients with diabetes mellitus: an audit.

The drug therapy prescribed for 412 diabetic patients attending an outpatient clinic over a 12 week period was recorded to try and identify potential therapeutic problems. Over 90% of the patients were prescribed at least one drug (including insulin) with oral hypoglycaemic agents prescribed for 86% of non-insulin requiring diabetics. 19% of patients were prescribed more than three drugs and few patients took drug combinations. Of patients prescribed either glibenclamide or chlorpropamide, 63% were aged 65 yr or older. Despite their potential adverse clinical and biochemical effects, diuretics and beta-blockers were commonly prescribed, especially in hypertension. The prescribing of "newer" anti-hypertensive drugs, combination products in patients taking a multiple drug regimen, and the potential dangers of sulphonylureas in the elderly are three areas where alteration of prescribing habits may be of value.

Adrenergic beta-Antagonists

Effects of RMI 12,936, a synthetic antiprogestational steroid, on the oestrous cycle and ovulation in the rat.

RMI 12,936 inhibited the vaginal cycle and ovulation in the rat. This effect was not mimicked by oestrogen and was partly reversed by progesterone. Ovulation was restored by injection of hCG and the inhibition was associated with reduced cyclic and tonic LH secretion while hypophysial LH levels were generally unaffected. Hypophysial sensitivity to LH-RH was reduced compared with that when ovulation was blocked with sodium pentobarbitone. It is concluded that RMI 12,936 blocks ovulation by causing a reduction in hypophysial sensitivity to LH-RH and that this is probably an antiprogestational effect.

Androstenols

Voice control: an old technique reexamined.

The authors suggest the term implicit communication control more nearly describes the technique. In addition to the vocal element, the term includes the physical expressions of the face and hands.

Behavior Therapy