Prognosis after myocardial infarction: results of 15 year follow up

A total of 271 out of 757 patients who had suffered a myocardial infarction during 1966-7 were still alive after six years; these patients were subsequently followed up 15 years after the infarction. Two hundred and sixty eight (99%) of the patients alive at six years and 519 (95%) of the 549 originally discharged from hospital were traced. A coronary prognostic index, which had predicted survival both to three years and from three to six years after recovery from the infarct also predicted survival from six to 15 years after recovery. The major factor affecting survival to 15 years was age at the time of the original infarct. Among patients aged under 60 at the time of infarction women fared better than men (p = 0.027). Factors in the coronary prognostic index that were associated with impairment of left ventricular function at the time of infarction and that had predicted mortality to three years and from three to six years also predicted mortality from six to 15 years. These factors were cardiac enlargement, pulmonary venous congestion, and the presence of infarction before the index infarct. The dominant cause of death remained coronary heart disease and its complications.

Effect of parenteral immunization on the local immunoglobulin A response of the intestine to Shigella flexneri antigens

Most traditional methods of immunization involve parenteral vaccines. Using a chronically isolated ileal loop model as the probe, we examined the effect of a primary parenteral immunization on the local immune response of the intestine. Secretions from isolated ileal loops of rabbits given a primary parenteral immunization with Shigella flexneri without adjuvant showed a small, but definite, specific immunoglobulin A (IgA) response locally, whereas a vigorous serum antigen-specific IgG response was elicited. Also, stronger antigen-specific IgG activity was detected in secretions of parenterally immunized animals than from animals given shigella only by oral immunization. No local IgA or IgG memory response could be elicited by prior parenteral priming with S. flexneri antigens. Lastly, no increase in the primary local IgA response was found in secretions from animals given an oral dosage regimen previously shown to prime for mucosal memory and then challenged with a single parenteral dose of the same antigen. These studies demonstrate that without adjuvant, parenteral doses of S. flexneri antigens elicit both specific serum and local immune responses, but they are not able to prime for a mucosal memory response upon subsequent mucosal challenge. The implications of these findings for programs that use parenteral vaccination to protect against mucosal diseases are discussed.

Pharmacokinetics of valproic acid in young and elderly subjects

The disposition of valproic acid was studied following single dose intravenous administration in seven young male volunteers aged 20-35 years and six elderly male in-patients aged 75-87 years. Following administration of 400 mg sodium valproate, blood samples were collected for 48 h and valproic acid concentrations analysed by enzymatic immunoassay. The median elimination half-life was 7.2 h in the young subjects but 14.9 h in the elderly patients (P less than 0.01). However, clearance did not differ significantly between groups, the values for young and old being 0.69 and 0.58 1/h respectively. The prolonged half-life resulted from a greater volume of distribution in the elderly. The median values (1/kg) for young and old were 0.13 and 0.19 respectively (P less than 0.01). These pharmacokinetic changes are unlikely to be of clinical importance.

Tangier disease with normal serum cholesterol

Three patients with Tangier Disease (hypoalphalipoproteinaemia) from the same family are described. One shows the classically described lipid abnormalities of the disease, with a low serum cholesterol level, and almost absent high density lipoprotein (HDL). However, two of his siblings, although demonstrable as Tangier homozygotes, have serum cholesterol levels within the normal range. This anomaly has arisen because they are also heterozygous for familial combined hyperlipidaemia. The pattern of inheritance of the two disorders, Tangier Disease and combined hyperlipidaemia, appears to be unrelated.

Immune complex-like activity associated with abnormal serum lipoproteins in systemic erythematosus

Sera from four patients with systemic lupus erythematosus (SLE) were shown to contain abnormal lipoproteins which behaved as immune complexes (IC). One IC lipoprotein (IC VLDL) had the density in ultracentrifugation of very low density lipoprotein, but a markedly altered electrophoretic mobility. A second IC lipoprotein (IC LDL) had the electrophoretic mobility of very low density lipoprotein but was slightly denser than low density lipoprotein on ultracentrifugation. Both the IC VLDL and IC LDL contained IgG and behaved as IC in the Clq deviation test, platelet aggregation and rheumatoid factor inhibition assays, but not in the conglutinin and Clq binding assays and the Clq solid phase assay. These differences could be due to the low densities of the IC VLDL and IC LDL. The abnormal lipoprotein IC disappeared with clinical remission in two patients and were not present in the sera of other patients with inactive or mild SLE, Type IV hyperlipidaemia, or during prednisone therapy or plasma exchange for other conditions. These IC appeared to be markers of severe and active SLE.

Noradrenaline release and clearance in relation to age and blood pressure in man

Plasma noradrenaline concentration increases with age. This study was designed to investigate whether an increased rate of noradrenaline release into the circulation or a decrease in clearance is primarily responsible for this age related change in concentration. Sixteen healthy male subjects were studied, eight young (21-36 years) and eight old (65-78 years). Clearance was calculated from steady state noradrenaline concentrations during constant rate infusions of unlabelled noradrenaline. Clearance did not differ between the two groups: young 4.8 l/min (range 2.7-6.1), old 4.1 (range 2.6-8.2). The old subjects had significantly greater rates of release. Supine: young 10.3 nmol/min (range 5.3-17.6), old 19.7 (range 10.1-30), P less than 0.05. Standing: young 17.2 (range 11-36.4), old 29.2 (range 21.8-47.9), P less than 0.01. No significant relationship was found in either supine or standing position between rate of noradrenaline release and either systolic or diastolic blood pressure. These results indicate that plasma noradrenaline concentration rises with age because of an increased rate of release, but that this increased release is not responsible for the higher blood pressure seen in the elderly.

Prazosin disposition in young and elderly subjects

1 The disposition of prazosin following oral and intravenous administration has been studied in seven young and seven elderly men, all of whom were in good health and living independently in the community. 2 The elimination half-life (min) of prazosin was 123 +/- 19.4 (s.d.) in the young and 194 +/- 36 in the elderly (P less than 0.01). 3 Clearance (ml min-1 kg-1) was 3.94 +/- 0.73 in the young and 3.53 +/- 1 in the elderly (P greater than 0.1). Volume of distribution at steady state (1 kg-1) was 0.63 +/- 0.14 in the young and 0.89 +/- 0.26 in the elderly (P less than 0.05). 4 The absolute bioavailability of orally administered prazosin was 0.68 +/- 0.17 in the young and 0.48 +/- 0.16 in the elderly (P less than 0.05). 5 The significant increase in prazosin half-life in the elderly results from an increased volume of distribution, not from decreased clearance. 6 Gastrointestinal absorption of prazosin decreases in old age.

Demonstration of neutrophil dysfunction in the serum of patients with cystic fibrosis

The neutrophil function of 12 patients with cystic fibrosis was evaluated via the new Immunobead/NBT dye reduction test. While the neutrophils appeared to be hyperfunctional when studied in the standard assay using fetal calf serum, we demonstrated a significant neutrophil dysfunction when studied in their own respective serum. The dysfunction involved both the phagocytic and intracellular killing ability of the cells, which we postulate is due to an inhibitory factor present in the patient's serum. The inhibitory factor did not appear to be related to the level of circulating immune complexes.

Very low density lipoprotein metabolism in domestic pigs

Patterns of triacylglycerol (TG) turnover in plasma and liver, and the hepatic secretion of very density lipoprotein triacylglycerol (VLDL TG) into the circulation, have been studied in young Large White female pigs, using i.v. tracer [1,3-14C]- and [2-3H]glycerol. Serial measurements were made of plasma [14C]glycerol and [14C]glucose and of liver TG and plasma VLDL TG specific activities. In other studies VLDL TG obtained from a donor pig was reinjected into recipient animals to measure the early disappearance (dilution) of VLDL TG. Multicompartmental analysis revealed a mean rate of hepatic TG turnover somewhat slower than the rate of VLDL TG turnover, suggesting that almost all of the hepatic TG turnover was due to secretion of VLDL TG, and that the intestine probably contributed an appreciable part of the newly synthesized plasma VLDL TG. The t1/2 of reinjected VLDL TG, whether prepared by the most rapid possible techniques and reinjected immediately or stored for several days, was approximately 10 min. This was much faster than the t1/2 of the falling limb of the plasma VLDL TG curve seen after injection of labelled glycerol (t1/2 approximately 2 H). Thus, in these respects, the pig resembled all other species studied rather than human subjects as described by Farquhar et al.

Arterial connective tissue changes and distribution of 125I-labelled low density lipoprotein in hypertensive pigs

Young pigs with hypertension of 10 weeks duration, resulting from cellophane perinephritis, were injected with 125I-labelled low-density lipoprotein ([125I]LDL) before being killed 24 h or 48 h later. Intimal thickening and increased acid mucopolysaccharide were demonstrated in the aortas and major arteries of the hypertensive animals. Increased accumulation of [125I]LDL was observed in the inner media beneath areas of intimal thickening. It is suggested that the primary effect of hypertension in atherosclerosis is to produce structural changes in arterial connective tissue which allow increased accumulation of LDL by altering the permeability and binding properties of the arterial wall.