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Biomedical subjects

A R Lorimer

Publications and source records attributed to A R Lorimer.

At least 109 records · Page 6Linked to original sources
PubMed1976

Low density lipoprotein metabolism in a family of familial hypercholesterolemic patients.

A low-density lipoprotein turnover study was performed on six heteroxygous familial hypercholesterolemic subjects and five control subjects. The diagnosis of the condition was clear-cut on biochemical, clinical, and genetic grounds. Kinetic analysis of the plasma decay curves gave the following mean values: (1) The plasma concentration of low density lipoprotein apoprotein (apoLDL) in the affected subjects was 247 mg/dl, a 2.5-fold increase over control values (98 mg/dl). (2) The calculated fractional catabolic rate of the intravascular apoLDL pool in the dyslipo-proteniemics was reduced with respect to control data (16.4%/day versus 31.2%/day), and the half-life of the apolipoprotein was correspondingly increased (6.07 days versus 3.63 days). (3) The absolute catabolic rate of the apoLDL was 15.6 mg/kg/day in contrast to the lower value of 11.6 mg/kg/day in the control group. (4) A strong negative correlation was observed between the plasma apoLDL concentration and the fractional catabolic rate (r = 0.96). We conclude from our data that increased apoLDL synthesis coupled with a defective or saturated catabolic mechanism is implicated in the pathogenesis of familial hypercholesterolemia.

Adult↗
PubMed1976

Lipoprotein levels in apparently healthy men and women in the west of Scotland.

Lipoprotein typing was undertaken in apparently healthy women (419) and men (103) in whom measurements of fasting total cholesterol, triglycerides, and cholesterol content of the major lipoprotein fractions were made. In the female group (30 to 59 years) there was a significant rise in total cholesterol, low density lipoprotein (LDL) cholesterol, and triglycerides with age. Using total cholesterol and triglyceride levels for classification, type II hyperlipoproteinaemia was present in 1 per cent and type IV in 6-7 per cent. When LDL cholesterol levels were also considered, type II occurred in 9-8 per cent ( 8-4% type IIA and 1-4% type IIB). In the male group ( 40 to 59 years) there was no increase in cholesterol or triglyceride levels with age: II per cent had type IV hyperlipoproteinaemia and none had a type II abnormality. When LDL cholesterol levels were also considered, type II occurred in 3 per cent ( 2% type IIA and 1% IIB). The apparent increase in LDL cholesterol frequency of type IIA abnormality in women could be merely the consequence of arbitrary selection of upper limits of normality for LDL cholesterol, but may signify improved detection of a high risk group.

Adult↗
PubMed1976

Comparison of 12-lead and computer-analysed 3 orthogonal lead electocardiogram in coronary artery disease.

The computer-analysed 3 orthogonal lead system ("3-lead ECG") provides a rapid and consistent interpretation of the electrocardiogram. In 102 patients undergoing selective coronary arteriography, the ability of such a system to predict the presence of absence of coronary artery disease and the site of myocardial ischaemia was compared with that of the conventional scalar electrocardiogram interpreted by cardiologists ("12-lead ECG"). Each system predicted the site of myocardial ischaemia with equal accuracy. The 3-lead ECG was a more sensitive index (3-lead ECG sensitivity=77%; 12-lead ECG sensitivity=70%) but less specific (3-lead ECG specificity=74%; 12-lead ECG specificity=78%). In coronary artery disease, the predictive "index of merit" for the 3-lead ECG was 0-51, compared with 0-48 for the 12-lead ECG. These results provide further justification for the routine use of the 3 orthogonal lead electrocardiogram.

Adult↗
PubMed1976

Mitral valve replacement in the presence of severe pulmonary hypertension.

Thirty patients with severe preoperative pulmonary hypertension (pulmonary artery pressure range 90-165 mmHg, mean 118 mmHg) were reviewed following single mitral valve replacement, with prosthetic valves, within the last 10 years (1964-74). The early and late mortality for this group was no different from that of the total series of mitral valve replacements performed over the same period. Marked postoperative clinical improvement was accompanied by corresponding radiological and electrocardiographic changes. In addition there was a statistically highly significant haemodynamic improvement in the 21 survivors (mean survival time 5 1/2 years). At recatheterization the mean pulmonary artery pressure was 41-5%, the mean wedge pressure 46-3%, and the transpulmonary gradient (PAm-LAm) 36-1% of the preoperative values. It is concluded that gross pulmonary hypertension is not per se a contraindication to mitral valve replacement surgery.

Adult↗
PubMed1976

Indications for beta-adrenoceptor blocking drugs in hypertension.

The past 10 years have firmly established the role of beta-adrenoceptor blocking agents in the treatment of hypertension. They have been shown to lower systolic and diastolic blood pressure in the lying and standing position in mild, moderate and severe hypertension. Precise indications for beta-blockade have not yet been completely defined. Some authorities regard them as the drug of first choice in the management of most grades of idiopathic hypertension. There are in addition certain situations where beta-blockade seems especially suitable. These include the presence of associated coronary heart disease manifest either as angina pectoris or dysrhythmia. These agents can be introduced when side effects from other drugs are severe or intolerable and are valuable in the management of hypertensive young males since beta-blocking drugs do not interfere with sexual function. Compared with normotensive subjects 'stress' has been shown to produce excessive rise of blood pressure in those with labile or sustained idiopathic hypertension. After therapy with beta-blocking agents the rise in blood pressure after 'stress' is reduced. If labile and/or mild hypertension are the precursors of subsequently more severe sustained hypertension, then long term beta-blockade may help to control this response.

Adrenergic beta-Antagonists↗
PubMed1975

Relation between extent of coronary artery disease and severity of hyperlipoproteinaemia.

Lipoprotein analyses were performed in 133 male patients and were correlated with the coronary arteriographic findings. The prevalence of hyperlipoproteinaemia was significantly higher in those patients with coronary artery disease (P less than 0-02). In addition, the more extensive the degree of coronary artery pathology the higher were the plasma concentrations of total cholesterol, triglyceride, and low density lipoprotein (LDL) cholesterol. Hyperlipoproteinaemia was more prevalent in the younger patients with coronary artery disease (P less than 0-02).

Age Factors↗
PubMed1975

Tricuspid valve replacement: a five-year appraisal.

Organic disease of the tricuspid valve required surgery in 18% of all patients undergoing valve replacement over a five-year period. Differentiation of organic from functional disease is difficult and may be made only at open-heart surgery. The results of a series of 56 patients who underwent tricuspid valve replacement are presented; of these, 53 had organic disease. Operative mortality at the end of five years had fallen to 7% with significant clinical improvement in 79% of patients, a reduction in cardiothoracic ratio in 81%, and a low incidence of postoperative tricuspid incompetence.

Female↗
PubMed1975

Early results of heart valve replacement with the Björk-Shiley prosthesis.

The operation on and subsequent course of 88 patients with valve replacements using Björk-Shiley tilting disc prostheses has been reviewed in terms of mortality, clinical results, and valve function. The follow-up period varied between 6 months and 2 years. The hospital mortality was 17% and late mortality 8%. Of those who left hospital, 75% returned to full normal activity and required less (or no) drug therapy other than maintenance anticoagulation. There was one transient embolic episode. Significant intravascular haemolysis does not occur with this prosthesis.

Adult↗
PubMed1975

The prevalence of hyperlipoproteinaemia in vascular disease.

Surveys of the apparently healthy working population of the West of Scotland have revealed a high prevalence of hyperlipoproteinaemia (HIP). In males, type IV occurred more frequently (12%) than in females (3.3%), although obesity played an important part in this finding. HLP also occurred frequently (61%) in survivors of myocardial infarction (type II 39%, type IV 22%) but less frequently in peripheral vascular disease (38%), although there was a higher prevalence in females (47%) than males (32%) largely due to an increased prevalence of type IIa (29.5% cf 7.5%). HLP did not appear to play a significant role in cerebrovascular disease.

Adult↗
PubMed1974

The effects of a new beta-adrenoceptor blocking compound, tolamolol, on haemo-dynamics and myocardial function in man.

1 The effects of tolamolol on haemodynamics and myocardial contractility were investigated in two groups of six patients undergoing diagnostic cardiac catheterization.2 The intravenous administration of tolamolol (0.15 mg/kg) produced a significant fall in heart rate from a control value (87 +/- 7 to 62 +/- 3 beats/min) 5 min after administration and a concomitant fall in cardiac output from 4.7 +/- 0.9 to 3.5 +/- 0.8 litres/minute. There was no significant change in systemic blood pressure, pulmonary artery blood pressure or stroke volume.3 There was no change in left ventricular end diastolic pressure after tolamolol. There was a fall in the maximum rate of rise of the left ventricular pressure (LV dp/dt(max)) and the derived index of the left ventricular contractile state (V(max)).4 These results suggest that tolamolol has a predominantly negative chronotropic but also a lesser negative inotropic action on the heart.

Adrenergic beta-Antagonists↗