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Biomedical subjects

L Adams

Publications and source records attributed to L Adams.

At least 181 records · Page 10Linked to original sources

Host defenses in the aged: evaluation of components of the inflammatory and immune responses.

Host defenses were evaluated in 70 healthy aged volunteers. Individuals who had diseases or who were taking medication known to affect the inflammatory and immune responses were excluded from the study. Volunteers were followed for 24 months to correlate their state of health with the evaluation of host defenses. Polymorphonuclear leukocyte function and the serum opsonic capacity for Escherichia coli and Staphylococcus aureus were normal. Assays of complement components and activity revealed unexplained elevations in native C3 and properdin, normal concentrations of factor B, normal conversion of C3 by inulin, and normal levels of hemolytic complement. The levels of IgG and IgA did not differ from levels noted in younger controls, but the concentration of IgM was decreased and that of IgE increased. The prevalence of autoantibodies was low. None of the volunteers were anergic, but lymphocyte responses to mitogens were depressed in three-day cultures. The number and percentages of E-rosette-forming cells and cells bearing surface IgD or IgM were normal. No lymphopenia was noted.

Age Factors↗

Comparative peripheral and coronary haemodynamic effects of rimiterol and isoprenaline.

1. Rimiterol and isoprenaline produced significant dose-related increases in cardiac output. 2. These changes in cardiac output were accompanied by increases in heart rate and myocardial oxygen consumption which were similar for each drug and dose-related. 3. Isoprenaline in contrast with rimiterol produced direct coronary vasodilation, i.e. coronary vasodilation in excess of that required to meet increases in myocardial oxygen demands. 4. It is suggested that the beta-adrenergic receptors in the human coronary vasculature are mainly of the beta1 type. 5. Rimiterol, because it does not produce direct coronary vasodilation may be preferable to isoprenaline in the treatment of low-cardiac output syndrome where there is regional myocardial ischaemia, since it would be less likely to produce a "coronary steal" effect.

Adult↗

Effects of selective and non-selective beta-adrenergic blockade on coronary dynamics in man assessed by rapid atrial pacing.

The effects on coronary dynamics of propranolol and atenolol were studied in 12 patients undergoing cardiac catheterisation for suspected coronary artery disease. Myocardial blood flow was measured using the coronary sinus continuous thermodilution technique. Data were obtained immediately after drug administration and during rapid atrial pacing. The immediate effects were similar for both drugs. A significant reduction in heart rate was accompanied by a small reduction in myocardial oxygen consumption. Changes in coronary sinus flow induced by rapid pacing were closely related to changes in tension-time index. This relation was not modified by propranolol or atenolol. Neither propranolol nor atenolol therefore has significant coronary vasoconstrictor properties. Cardioselectivity appears to be unimportant with respect to beta-adrenergic blockade and the coronary circulation.

Adult↗

Haemoglobin Rahere (beta Lys-Thr): A new high affinity haemoglobin associated with decreased 2, 3-diphosphoglycerate binding and relative polycythaemia.

A new haemoglobin with increased oxygen affinity, beta82 (EF6) lysine leads to threonine (Hb Rahere), was found during the investigation of a patient who was found to have a raised haemoglobin concentration after a routine blood count. The substitution affects one of the 2, 3-diphosphoglycerate binding sites, resulting in an increased affinity for oxygen, but both the haem-haem interaction and the alkaline Bohr effect are normal in the haemolysate. This variant had the same mobility as haemoglobin A on electrophoresis at alkaline pH but was detected by measuring the whole blood oxygen affinity; it could be separated from haemoglobin A, however, by electrophoresis in agar at acid pH. The raised haemoglobin concentration was mainly due to a reduction in plasma volume (a relative polycythaemia) and was associated with a persistently raised white blood count. This case emphasises the need to measure the oxygen affinity of haemoglobin in all patients with absolute or relative polycythaemia when some obvious cause is not evident.

Adult↗

Carbon monoxide yields of cigarettes and their relation to nicotine yield and type of filter.

Carbon monoxide (CO) yields of 11 popular brands of British cigarette, two types of cigarette containing tobacco-substitute, and one brand of cigar were measured under standardized conditions. Yields of the conventional cigarettes ranged from 5.0 to 20.2 mg per cigarette (1.3 to 4.7% by volume). The cigar yielded 81.7 mg (10.0%) CO and the two semi-synthetic cigarettes 17.2 (4.2%) and 28.2 mg (6.2%) CO. Puff-by-puff analysis showed an increase in CO concentration as a cigarette is smoked. In brands with nicotine yields over 1.0 mg no relationship was apparent between nicotine yield and CO yield, and the filters of cigarettes in this category did not appear to reduce the CO yield. In the low nicotine cigarettes with ventilated filters there appeared to be some correlation between nicotine yield and CO yield, and these filters were highly effective in reducing CO yield, owing mainly to the ventilation. We suggest that official publication of CO yields might motivate manufacturers to produce cigarettes with lower yields.

Carbon Monoxide↗

A new method for the direct estimation of blood oxygen content.

Identical blood samples were estimated for oxygen content by a fuel cell analyser (the "Lex-O2-Con'), and by the Van Slyke manometric technique. The new instrument was found to be accurate and repeatable, as well as quicker and easier to operate. Its response to oxygen was found to be unaffected by the presence of common anaesthetic agents.

Blood Gas Analysis↗

Induction of antibodies to nuclear antigens in rabbits by immunization with hydralazine-human serum albumin conjugates.

The antihypertensive drug hydralazine can induce in man a syndrome similar to spontaneous systemic lupus erythematosus (SLE). The pathogenesis of this drug-induced syndrome is not understood. In this investigation, five groups of rabbits were studied: group I, 10 rabbits hyperimmunized with hydralazine conjugated to human serum albumin (HSA) in complete Freund's adjuvant (CFA); group II, four rabbits with HSA in CFA; group III, four rabbits with CFA alone; group IV, five rabbits with hydralazine conjugated to rabbit serum albumin (RSA); and group V, four rabbits with a major metabolite of hydralazine conjugated to HSA. The rabbits immunized with hydralazine-HSA developed rising titers of antibodies to hydralazine and progressively increasing amounts of antibodies to both single-stranded and native DNA. The antibodies to DNA were cross-reactive with hydralazine as determined by inhibition of DNA binding and DNA hemagglutination tests. Similar results were obtained in rabbits immunized with the metabolite-HSA compound except the major hapten antibody response was to the metabolite. The DNA antibodies in this group were also capable of being absorbed by metabolite-HSA as well as hydralazine-HSA, indicative of the cross-reactivity between hydralazine and its metabolite. Immunization with hydralazine-RSA caused rabbits to produce antibodies to hydralazine but not to DNA, indicating the requirement for an immune response to the carrier protein in order for antibodies reactive with DNA to be produced. Thus, hyperimmunization of rabbits with hydralazine-protein conjugates may provide a useful animal model of SLE. The data suggests that an immune response to hydralazine may be important in human hydralazine-induced SLE.

Animals↗