Nitric oxide (NO) plays an Important role In regulating platelet activation.Both endogenous and exogenous NO Inhibit platelet adhesion and aggregation in vivo.The aim of the present study was to assess the activity ol inhaled NO on platelet aggregation and pulmonary thrombosis.Rats were Intubated, catheterized, and ventilated for 2 h wtth room air (controls) or with 20, 40, or 80 pom of NO mixed wtth room air.Heparinized blood was then collected from 6 rats in each group via carotid artery catheterlzatton and PRP was prepared for aggregation studies performed within 30 mln.The in vivo antithromboUc activity of Inhaled NO was tested In rats using a model of lung platelet thromboembolism.For these purposes control rats (n -6) and rats subjected to 80 ppm of NO (n -6) were Injected intravenously with 2.5 mg/kg ol equine tendon collagen to induce platelet-rich thrombosis in the pulmonary vasculature, while pulmonary artery pressure was monitored continuously.Ten min after collagen injection, rats were sacrificed for histotogical examination of the lungs to evaluate the degree of pulmonary blood vessel occlusion by collagen-induced platelet-rich thrombi.The ex vivo platelet aggregation induced by 1 ug/ml collagen was reduced by 48% in the 40 ppm group and by 49% In the 80 ppm group, but was not inhibited in the 20 ppm group.Platelet counts In whole blood samples taken 3 min after collagen Injection revealed smaller decreases in platelet numbers for the 80 ppm NO group compared to controls (57 ± 9% vs 74 ± 7% decrease resp, P < 0.05).Simultaneously, pulmonary artery pressure rise was significantly greater in controls compared to the 80 ppm NO group (32 ± 4 vs 26 ± 3 mmHg, resp, P < 0.05).Histotogical examination demonstrated significantly more intrapulmonary thrombosis in control rats compared to 80 ppm NO treated rats, in accordance with increased mortality after 10 min (3/6, vs 0/6 in the 80 ppm NO group).Thus, NO inhalation (40 and 80 ppm) counteracts platelet activation by strong stimuli, both in vitro and in vivo, and may be therapeutically beneficial in pulmonary thromboembolic disease.

Male aginq is associated with alterations in plasma levels of antioxidants such as Coenzyme Q10 (CoQ10) , and with a decrease of the fat-free body mass (FFM). In order to reveal, whether these changes can affect CoQ10 metabolism, 73 non-obese, healthy males were studied, in age range 22–100 years, divided in 4 age groups: 20–55 (n = 23); 56–70 (n = 20); 71–90 (n = 8) and 91–100 (n =22). Serum CoQ10 was measured by HPLC technique. Body composition was assessed by multifrequency bioimpedance analysis. Subjects aged 91–100 years displayed lower serum CoQ10 levels and FFM than the other age-groups (p <0.001). Linear regression anlysis revealed significant correlations between FFM and age (r = − 0.82, p < 0.00001), serum CoQ10 and age (r = − 0.35, p <0.01). and serum CoQ10 and FFM (r = − 0.49, p < 0.001). Multiple regression analysis confirmed the correlation between serum CoQ10 and FFM (p < 0.01), but did not for serum CoQ10 and age. The proportion of FFM decreases with age. CoQ10 levels are also lower in older people, but they seem to be linked to FFM and not to aging itself. Since muscle tissue is the major component of FFM, and a reduction of the metabolic rate is another feature of aging, serum CoQ10 may be an indirect index of metabolic activity in the elderly.

Intense neurohormonal activation has been demonstrated in patients with primary or precapillary secondary pulmonary hypertension (PH) but the relation of neurohormons to functional impairment is not well known. Plasma levels of atrial natriuretic peptide (ANP), aldosterone (ALD), renin activity (PRA), epinephrine (PE), norepinephrine (PNE) and endothelin (ET) were assessed from the antecubital vein in 12 patients with primary PH, 7 patients with precapillary secondary PH (2 connective tissue disease, 2 chronic thromboembolic, 3 closed atrial septal defect) and 10 control subjects. Twelve patients were in NYHA functional class II (PH-II) and 7 in class III/IV (PH-III/IV). Mean PA pressure (PAP), cardiac index (CI), pulmonary vascular resistance (PVR) and right atrial pressure were assessed by heart catheterization:PAPCIPVRRAP(mmHg)(l/minlm2)(RU)(mmHg)PH-II53 ± 132.4 ± 0.412 ± 33 ± 2PH-III/IV61 ± 92.0 ± 0518 ± 611 ±5P0.170.070.0090.0001

Primary (PPH) or precapillary secondary (SPH) pulmonary hypertension show similar hemodynamic abnormalities and an intense neurohormonal activation has been detected in both syndromes. Comparative analysis of the neurohormonal profile and its relation to hemodynamics of patients with PPH and SPH are not available. Plasma levels of atrial natriuretic peptide (ANP). aldosterone (ALD). renin activity (PRA). epinephrine (PE). norepinephrine (PNE) and endothelin (ET) were assessed from the antecubital vein in 12 patients with PPH and 7 patients with SPH (2 connective tissue disease, 2 chronic thromboembolic, 3 closed atrial septal defect). Hemodynamics were measured by heart catheterization. Between PPH and SPH patients no differences were assessed on cardiac index (CI) (2.2 ± 0.2 vs 2.3 ± 03 l/min/m2, ns), mean pulmonary artery pressure (PAP) (55 ± 12 vs 58 ± 12 mmHg, ns), pulmonary vascular resistance (PVR) (14 ± 6 vs 14 ± 4 RU, ns) right atrial pressure (RAP) (4 ± 4 vs 8 ± 7 mmHg, p = 0.13) and mixed venous blood oxygen saturation (vSat) (62 ± 7 vs 65 ± 9%, ns). Neurohormonal parameters in patients with PPH and patients with SPH were as followsANP(pg/ml)ALD(pg/mi)PRA(ng/ml/h)PE(pg/ml)PNE(pg/ml)ET(pg/ml)PPH203 ± 139178 ± 1321.8 ± 2.1351 ± 420426 ± 3434.5 ± 3.1SPH210 ± 110220 ± 2622.5 ± 4.0268 ± 333637 ± 7206.9 ± 3.7pnsnsnsnsnsns

We tested the usefulness of a sustained intravenous infusion of nifedipine and a combination of nifedipine and metoprolol in the early management of 14 patients with unstable angina pectoris. After a 24-hour run-in period, nifedipine was titrated in a stepwise fashion (mean dose 27 +/- 7 micrograms/min). After nifedipine treatment coronary blood flow increased from 150 +/- 66 to 183 +/- 74 ml/min (p less than 0.05), whereas double product, myocardial oxygen consumption, and both arterial and coronary sinus (nor)epinephrine levels were unchanged. Myocardial lactate uptake increased from 3.4 +/- 26.1 to 31.3 +/- 26.6 mumol/min (p less than 0.005) and free fatty acid uptake from 7.2 +/- 22.1 to 34.5 +/- 33.7 mumol/min (p less than 0.05). A small nonsignificant improvement in amino acid metabolism was observed. Metoprolol was added in seven patients and led to a decrease in double product (-2.2 +/- 1.6 x 10(3); p less than 0.01) and myocardial oxygen consumption (-3.2 +/- 3.8 ml/min; p less than 0.05). The lactate uptake/oxygen uptake ratio increased by 18% after metoprolol (p = NS). The number of episodes of chest pain decreased from 2.4 +/- 1.1/24 hours to 0.1 +/- 0.2 in the nifedipine group and from 2.9 +/- 1.1/24 hours to 0.3 +/- 0.5 in the nifedipine plus metoprolol group (both p less than 0.01). We conclude that in the acute phase of unstable angina, intravenous nifedipine can be carefully titrated to improve coronary blood flow and oxidative metabolism. The addition of metoprolol is also associated with a reduction in myocardial oxygen demand. This treatment results in significant hemodynamic stability.

A simple, fast, fully automated method for plasma serotonin determination is described. Full automation is obtained by coupling two devices: a sample processing station and a solid-phase autosampler. The sample processing station dilutes the plasma sample and is then connected, on-stream, with the solid-phase autosampler. It firstly fills a loop with all the solvents necessary for the sample clean-up, then, inverting the flow, pumps these solvents through the silica-bonded cation-exchange disposable extraction cartridge positioned on the autosampler. For the elution, the cartridge is switched on-stream with the HPLC analytical column and serotonin is eluted by the HPLC mobile-phase. The HPLC separation is performed by ion-pairing reversed-phase liquid chromatography. The column effluent is completely reduced by an electrochemical reactor and serotonin is detected in an oxidation-mode by a dual-cell electrochemical detector. The plasma sample is 50 μl, the plasma sensitivity is 40 ng/l, the retention time is 6 min and the recovery is 95%. The repeatibility, the normal ranges for platelet-poor and for platelet-rich plasma have been established and correlation with manual HPLC calculated.

The urinary catecholamine metabolites, vanimandelic acid, homovanillic acid, 3,4-dihydroxyphenylacetic acid and 5-hydroxyindoleacetic acid, were extracted on a silica-bonded strong-anion-exchanger cartridge (SAX) and then injected into an high-performance liquid chromatographic (HPLC) system by column switching. Chromatography was performed on a reversed-phase analytical column with electrochemical detection. Full automation was obtained by coupling two devices: a solid-phase automatic sampler and intelligent autosampler. For each substance the recovery was greater than 95% and the coefficient of variation was ca. 3%; the analysis takes 11 min. Substance instability problems are overcome, because the samples are extracted and injected in rapid succession. The normal values and correlation with manual HPLC were established for a large number of samples.

The results of a study on 68 VDT operators are hereby presented. Various biochemical indexes are evaluated as markers of stress. In particular, urinary catecholamines and their metabolites (E, NE, DA, HVA, VMA), ACTH, cortisol, NEFA and fructosamine have been tested by the Authors. Each assay has been performed both in basal conditions, and after the completion of subjects workshift, taking into account the normal hormonal biorhythms. The data which emerged have been analyzed by statistical method ("Student t" with coupled data). Each subject data was confronted before and after workshift. The number of hours of VDT exposure and the different types of duties have been considered and evaluated. The results show that, although the data are all included within the normal range, some of the tested parameters after workshift are significantly higher, compared with the same parameters referring to the basal condition. In particular, Epinephrine and Norepinephrine seem to be the most effective markers of stress. Analogous studies will be pursued in the future by the Authors on a larger number of VDT operators.

A fully automated analyzer is described for the HPLC analysis of catecholamines.