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Biomedical subjects

R Rossi

Publications and source records attributed to R Rossi.

At least 415 records · Page 23Linked to original sources
PubMed1988

Effect of penbutolol on circadian blood pressure, and renin, aldosterone and cortisol levels in patients with essential hypertension.

We investigated the effect of an orally administered, long-acting, beta-adrenergic blocking agent, penbutolol, on the circadian rhythm of blood pressure (BP) and heart rate (HR), and plasma renin activity (PRA), aldosterone (PA) and cortisol (PC) levels in hospital patients with essential hypertension validated by a chronobiological inferential statistic method. After a wash-out period of three weeks, a group of 8 hypertensive patients (5 women and 3 men, 27 to 41 years old) underwent automatic BP and HR monitoring, and blood sampling for 24 hours in a hospital room before and after 4 weeks of treatment with penbutolol (40-mg tablet once a day at 9 a.m.). In basal conditions, a statistically significant mean circadian rhythm was demonstrated for HR, diastolic BP, PRA, PA, and PC. Systolic and diastolic BP were lowered by penbutolol, with only a minor decrease of HR. The treatment eliminated also the mean circadian rhythm of BP and HR. Penbutolol induced both a remarkable reduction of PRA with disappearance of the related circadian rhythm and a significant decrease in PA levels with maintenance of their circadian rhythmicity. The circadian secretory patterns of PC were similar before and after therapy. In conclusion, long-term treatment with penbutolol appears not only to set BP, PRA and PA values to lower levels, but also to decrease the within-day variation of BP, HR, and PRA. In addition, penbutolol does not influence the 24 h-secretion of PC.

Administration, Oral↗
PubMed1987

Conformational changes in diphtheria toxoids. Analysis with monoclonal antibodies.

Monoclonal antibodies (Mab) were raised against CRM197, a non-toxic mutant of diphtheria toxin (DT). The ability of four Mabs to bind DT and the six functional mutants CRM197, CRM176, CRM228, CRM1001, CRM45 and CRM30 was assessed by immunoblotting and by a radioimmunoassay in which the protein antigen in solution competes with labeled CRM197 for the Mab binding site. The results show that the peptides recognized by Mab11.3, Mab53 and Mab23 are accessible in the mutant molecules in solution but not when they are part of the native DT structure, which could therefore be described for this purpose as 'closed' in contrast with an 'open' conformation of CRM197, CRM176 and CRM228. In particular, the behaviour of Mab53 indicates that the single amino acid substitutions in the A fragments of CRM197 and CRM176 also affect the conformation of their B fragments.

Amino Acid Sequence↗
PubMed1987

Individual knowledge of emotions in asthmatic children.

Twenty male asthmatic children (ages 9-11) and their controls were interviewed regarding their concept of emotion using the interview format developed by Harris et al. (1981). The purpose of the study was to examine the asthmatic children's views on the nature and effects of happiness, anger and fear, together with strategies of self-control. The results indicate that healthy and asthmatic children have a different individual view of emotion. The most relevant finding concerns the different way in which healthy and asthmatic children consider fear: the most frequent view of fear in healthy children is similar to a behaviouristic model of emotion, while asthmatic children express a notion very similar to a cognitive model. Regarding anger, almost all healthy children believe themselves capable of exerting self-control whether on the inner mental components or on its outer expression, where a change of direction of mental processes is the only way asthmatic children see to modify their anger. The implications of these findings both for a description of asthmatic personality and therapy are outlined.

Anger↗
PubMed1987

Description and evaluation of a method for computer analysis of the exercise electrocardiogram.

The new approach to computer processing of exercise electrocardiography has been made easier by the development of microcomputers. Studies are necessary to validate analyzed electrocardiographic data for the diagnosis of ischemia. We describe and assess in this paper a new program for the analysis "on line" of 12 leads during effort. The program detects "normal QRS" and ectopic beats. Amplitude of R wave, length of QRS, ST level after a programmable delay from J point, ST maximal slope and amplitude of T wave are calculated and recorded every 15 sec in the 12 leads. In 200 exercise stress tests quantitative data provided by the processor were compared with visual analysis and with clinical data. ST level less than or equal to -0.8 mm and ST slope less than or equal to 1.2 mV/sec or ST level greater than or equal to +2.0 mm and ST slope less than or equal to 0.6 mV/sec were the best analyzed criteria for ischemia. Using these criteria, sensitivity increased from 86.6% by visual reading to 92% by computer analysis, without change in specificity (94%).

Adult↗
PubMed1987

Field trial of vaccination against American trypanosomiasis (Chagas' disease) in domestic guinea pigs.

Domestically bred South American guinea pigs received 3 to 5 immunizing intradermal inocula of 28 X 10(6) live attenuated Trypanosoma cruzi epimastigotes (TCC strain) per kg. These inocula were unable to produce patent infections or to propagate through vectors. Groups of experimental and control guinea pigs were exposed to natural T. cruzi infection in a field yard for periods of up to 551 days. Xenodiagnoses were applied periodically to all animals. This showed that the incidence of natural T. cruzi infection was significantly lowered at various periods post-exposure. The final proportion of infected animals was 39% (20/51) among vaccinees vs. 63% (32/51) among controls (P less than 0.02). The protective effect was exerted particularly upon males and lasted for over a year in one experimental series (infection in 1/7 vaccinees vs. 6/7 controls, P = 0.014). Vaccination reduced vector transmission rates from 38% to 18% (P less than 0.001). These results agree with previous laboratory experiments in showing a partial resistance which does not eliminate residual T. cruzi infection. However, the field work indicates that even this kind of resistance may have epidemiological impact, reducing both the number of reservoirs spreading the disease and the rate of vector transmission.

Animals↗
PubMed1987

Intensive care units as a source of methicillin-resistant Staphylococcus aureus.

Over a 12 month period, 209 isolates of methicillin resistant Staphylococcus aureus (MRSA) were obtained in 39 patients admitted to an ICU. In 23 patients MRSA was the major pathogen, producing either pneumonia, bacteremia or wound infection. In eight patients death was directly related to the MRSA infection. This study suggests an increasing occurrence of MRSA infections in ICU and the need to adopt control measures.

Adolescent↗
PubMed1986

Detection of cerebral injury after total circulatory arrest and profound hypothermia by estimation of specific creatine kinase isoenzyme levels using monoclonal antibody techniques.

New 2-site labeled monoclonal antibody techniques were used to measure serially plasma levels of brain-type creatine kinase (CK-BB), heart-type creatine kinase (CK-MB) and muscle-type creatine kinase (CK-MM) during a 20-hour postoperative period in 24 infants after deep hypothermia and total circulatory arrest used in pediatric cardiac surgery. A control group of 7 children undergoing cardiovascular procedures without extracorporeal circulation or circulatory arrest also were studied. There were marked increases in CK-MB and CK-BB levels in the circulatory arrest group but not in the closed group. CK-BB increased from 3.2 +/- 0.5 to 27 +/- 10 ng/ml and CK-MB from 5.9 +/- 2.1 to 137 +/- 12 ng/ml. The CK-MM concentrations increased from 299 +/- 91 and 194 +/- 49 ng/ml to 1,220 +/- 274 and 1,322 +/- 142 ng/ml in the closed and circulatory arrest groups, respectively. Peak levels of CK-MB and CK-BB occurred an average of 133 and 127 minutes, respectively, after reperfusion. The half-time of CK-BB differed significantly from that of CK-MB (149 +/- 15 vs 359 +/- 20 minutes). The arrest time had a more marked effect on CK-BB concentration than on CK-MB and CK-MM concentrations. Arteriointernal jugular venous concentration differences were consistently negative for CK-BB in the circulatory arrest group, but not for CK-MM and CK-MB.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1986

Low-renin primary hypertension in a young patient treated with dexamethasone.

We have studied a young untreated patient with low-renin hypertension. All the clinical tests were in normal range, except plasma renin activity, which was low. Also all traditional tests evaluating the adrenal function were normal. A test of supraphysiological ACTH stimulation revealed a partial enzymatic defect of adrenal 11-hydroxylase. The patient has been treated with dexamethasone (0.75 mg once daily), during 4 weeks. At the end of the treatment blood pressure reached normal values. The traditional adrenal function tests are not sufficient to exclude enzymatic abnormalities and their possible involvement in the pathogenesis of hypertension.

Adrenocorticotropic Hormone↗
PubMed1986

Remarks and experiments on the construction of respiratory waveforms from electrocardiographic tracings.

We report on some observations and preliminary experiments on the deduction of respiratory waveforms from electrocardiographic traces by interpolating the values of angles related to a cardiac electrical axis. The experiments concern comparing the trends obtained from different definitions of the cardiac electrical axis: respiratory waveforms deducted by considering the electrical axis of either the QRS complex or the T wave, and those deducted in the presence of cardiac rhythm disorders, noise, and drifts. The most significant result was obtained when, starting from an ECG trace, we were able to plot curves that were very close to the respiration curve obtained from a belt impedance meter. This result indicates that the objective can be attained. Other results concern specific cases and the constraints to be observed. Among those, arrhythmia, missing beats, pauses, noise, and drifts superimposed on the original ECG traces.

Arrhythmias, Cardiac↗