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The in situ identification of lymphocyte subpopulations by means of immunopathological techniques using specific monoclonal antibodies provides a tool for the study of the gastrointestinal-associated lymphoid tissue (GALT) in health and disease. In this field, monoclonal antibodies have been applied previously using light microscopy and either immunofluorescence or immunoperoxidase; however, these techniques are not sensitive enough to allow precise evaluation of localization of labelling. We describe an immunoelectronmicroscopic method, which defines labelling specificity, since it allows the identification of cells by immunophenotype labelling and ultrastructural markers simultaneously. This in turn allows a better evaluation of the labelled cells and of the relationship between labelled and unlabelled cells. The main features of the method are the use of fresh tissue samples, fixing in paraformaldehyde CaCl2, and the coupling of the immune reaction to an amplification system (avidin-biotin-peroxidase complex). The technique yields a good preservation of cellular ultrastructure, together with a strong and specific immunolabelling. Our results confirm the high specificity of monoclonal antibodies when applied to immunopathology techniques. We confirm the pattern of distribution of various lymphocyte subsets in the jejunal mucosa described by other authors by light microscopy.

Intracellular free calcium, [Ca2+]i, was studied in platelets of essential hypertensive subjects and normotensive controls under basal conditions and after stimulation with epinephrine, norepinephrine, angiotensin II, ouabain, and thrombin, using the fluorescent calcium indicator quin 2. Basal [Ca2+]i was significantly higher in hypertensive subjects (n = 32) than in normotensive controls (n = 30; 167.4 +/- 5.0 vs 143.2 +/- 3.1 nmol/L; p less than 0.001). Epinephrine, norepinephrine, angiotensin II, and ouabain had no effect on platelet calcium, whereas thrombin induced a dose-dependent increase in [Ca2+]i in both the presence and absence of extracellular calcium. This [Ca2+]i increase in the presence of extracellular calcium, which depends mainly on calcium influx, was significantly higher (p less than 0.05) in platelets of hypertensive subjects at all thrombin concentrations (ranging from 0.025-0.1 U/ml), while the [Ca2+]i increase in the absence of extracellular calcium, which depends only on release from intracellular stores, was similar in hypertensive subjects and controls. These results suggest that, in essential hypertension, there is not only increased platelet resting [Ca2+]i but also an increase in agonist-mediated calcium influx, which appears to indicate a cell membrane abnormality in the platelets of subjects with essential hypertension.

The Authors analyze the clinical and biological meanings of some markers of coagulative activity (beta thromboglobulin, PF4, fibrinogen, fibrinopeptide A) and their changes in some arterial diseases. The role of main atherosclerosis risk factors (dyslipidaemia, hypertension, smoking and diabetes) in promoting a thrombophylic state in these pathological conditions is also considered. Finally the Authors evaluate the usefulness of the markers of coagulative activity from both a diagnostic and a preventive point of view in the arteriopathies of atherosclerotic etiology.

Urinary and kidney kallikrein were studied in rats with renal clip hypertension. The effect of protease inhibitors on urinary and kidney BAEE esterase activity was similar. Both hypertensive and not hypertensive operated rats excrete significantly less kallikrein than controls; in the ischaemic kidney kallikrein is diminished whereas is not increased in contralateral. Kallikrein is therefore related to renal functional mass but does not seem responsible for a natriuretic effect.

1. The 24 h urinary excretion of kallikrein has been studied in 40 normotensive control subjects and in 74 age-matched patients with essential hypertension under similar conditions. By use of the renin-sodium index, hypertensive patients were divided into two subgroup: low-renin hypertension and normal-renin hypertension patients. Urinary kallikrein determinations were also obtained from six hypertensive patients with primary aldosteronism. 2. Urinary kallikrein was significantly lower both in patients with normal-renin and low-renin essential hypertension. Urinary kallikrein excretion was very high in the patients with primary aldosteronism. 3. In nine hypertensive patients beta-adreno-receptor-blocking therapy caused a significant decrease of plasma renin activity, but had no significant effect on urinary kallikrein excretion. 4. The results support the concept that low urinary kallikrein is likely to be a marker of essential hypertension. Under certain conditions its excretion is positively related to mineralocorticoid hormone concentrations but it is not primarily related to the renin-angiotensin system.

The presence of tubular involvement, as a marker for the detection of urinary tract infection (UTI) site, was examined in 19 patients with pyelonephritis and in 15 patients with cystitis or asymptomatic bacteriuria. The urinary excretion of four markers of tubular proteinuria, beta 2-microglobulin (beta 2M), lysozyme (LZ), lactic dehydrogenase isoenzyme V (LAD-5) and N-acetyl-beta D-glucosaminidase (NAG), was investigated. LAD-5 appeared particularly valuable for the early detection of upper UTI. However, the overall diagnostic accuracy appeared to be further strengthened using, besides LAD-5, one additional variable. A set of simple and noninvasive biochemical tests on urine samples can reliably help to identify the site of UTI.