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Biomedical subjects

M Iacob

Publications and source records attributed to M Iacob.

At least 19 recordsLinked to original sources
PubMed2003

Restenosis in the coronary stent is an argument for the surgical myocardial revascularization.

BACKGROUND: This study will evaluate the difference between the frequency of restenosis in myocardial revascularization procedures by stents and CABG by coronarographic control after clinical criteria (angina). METHODS AND RESULTS: Out of the total of 6564 coronarographies performed (1999-2002) for diagnosis purposes, 3110 patients (44.8%) underwent myocardial revascularization procedures, PCI or CABG. PCI was performed in 981 patients (31%) and CABG in 1148 patients (37.3%). At the same time, we performed in our units 2067 surgical procedures, out of which 1148 (55%) revascularizations by CABG. The angiographic control for patients with myocardial revascularization by stent (55 patients) or CABG (50 patients) was performed by clinical criteria (angina reappears) on 105 patients. The restenosis we found in 47 patients (74.5%) treated by stent revascularization and in 29 patients from CABG procedures. In our study restenosis rate was 4.8% in patients with PCI and 2.5% in patients with CABG. CONCLUSIONS: Both surgical (CABG) and percutaneous coronary artery revascularization (PCI) have proved to be extremely effective in the treatment of patients with multivessel coronary disease. In our study restenosis rate was smaller in the patients with CABG than in the PCI group, taking into account the fact that we did not use drug eluting stent (DES) on a large scale. Results from the series of randomized trials (SOS, SIRIUS, ERACI, ARTS, BARI, etc.) have shown that the restenosis phenomenon is an apparent advantage in patients with DES. Restenosis prevention is a complex phenomenon (inflammation, procoagulation, cellular migration, etc.) and DES appearance opens a new era in PCI.

Angina Pectoris↗
PubMed2001

Chronic ACE inhibition enhances the endothelial control of arterial mechanics and flow-dependent vasodilatation in heart failure.

Reduced conduit arteries flow-dependent dilatation and altered compliance have been described during heart failure. However, the role of shear stress, the relation between endothelial dysfunction and mechanics, and the effect of chronic ACE inhibition on this relationship have not been investigated. The present study was designed to evaluate in heart failure patients the relationship between flow-dependent dilatation and radial artery mechanics at known shear stress levels and to assess the effect of chronic ACE inhibition. Sixteen stable congestive heart failure patients, who had never been treated with ACE inhibitors, participated in the study. Arterial pressure, cardiac output (bioimpedance), radial artery diameter (echo tracking) and flow (Doppler), total blood viscosity, and mean artery wall shear stress were assessed before and during a gradual increase in the forearm blood flow in response to gradual distal hand skin heating. Cross-sectional radial artery compliance and distensibility indexes were calculated at 34 degrees C, 40 degrees C, and 44 degrees C. The endothelium-independent vasodilatation was evaluated by use of glyceryl trinitrate. All parameters were assessed before and 24 hours after the last administration of perindopril (4 mg once daily) or placebo in a 2-month double-blind randomized study. Before treatment, there was no difference between the 2 groups for all parameters. After chronic ACE inhibition, systolic arterial pressure decreased at baseline from 126+/-11 to 118+/-10 mm Hg (P<0.05). During heating, the increase in diameter in response to shear stress was higher after ACE inhibition than after placebo (time/treatment interaction, P<0.05). Moreover, in contrast to placebo, at the same shear stress, there was a significant increase in compliance (3.23+/-0.79 x 10(-7) to 6.82+/-2.47 x 10(-7) m(2)/kPa, P<0.05) and distensibility (5.71+/-1.35 x 10(-3) to 8.87+/-1.88 x 10(-3)/kPa, P<0.05) during heating after ACE inhibition. The effect of glyceryl trinitrate did not change. The present study demonstrates that chronic administration of the ACE inhibitor perindopril increases the magnitude of the flow-dependent dilatation and restores the flow-dependent increase in compliance and distensibility of the radial artery evaluated at stable shear stress. In addition, the decrease in baseline systolic arterial pressure after ACE inhibitor suggests an associated increase in the distensibility of the proximal elastic conduit arteries.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2001

Role of arterial smooth muscle tone and geometry in the regulation of peripheral conduit artery mechanics by shear stress.

1. Although arterial blood flow is recognized as an important modulator of vascular tone and geometry, the effect of acute changes in shear-stress on conduit artery mechanics has not been fully investigated in humans because of technical limitations. 2. To assess, respectively, the effects of decreases and increases in flow and shear stress on radial artery tone and mechanics, arterial pressure (photoplethysmography), total blood viscosity, radial artery internal diameter, wall thickness (echotracking) and blood flow (Doppler) were measured in healthy volunteers (mean (+/-SEM) age 25 +/- 1 years) during a distal flow arrest (n=12) and hand skin heating (n=18). 3. Radial artery flow decreased from 31 +/- 4 to 7 +/- 1 10(-3) L/min during distal flow arrest (P < 0.001) and increased from 10 +/- 2 to 22 +/- 4 and 69 +/- 6 10(-3) L/min during heating (P < 0.001). At mean arterial pressure, these changes in flow were respectively associated with a parallel flow-dependent reduction and increase in diameter and midwall stress. There was no significant modification in mean elastic modulus. Compliance did not change when flow decreased and only increased at the highest level of flow. Finally, the cross-sectional compliance and incremental modulus were fitted as functions of midwall stress. The decrease in flow was associated with an upward shift of the modulus-midwall stress curve and a downward shift of the compliance-midwall stress curve. The increase in flow was associated with a downward shift of the modulus-midwall stress curve and an upward shift of the compliance-midwall stress curve at each level of wall shear stress. 4. By using two different procedures, we obtained similar results concerning the direct effects of increases and decreases in flow on stiffness of the arterial wall and on arterial compliance and demonstrated the presence of a flow-dependent regulation of arterial smooth muscle tone of peripheral conduit arteries in humans.

Adult↗
PubMed1998

Divergent effects of verapamil and amlodipine at rest and during exercise.

OBJECTIVE: To evaluate, in healthy volunteers, the effects of acute administration of two calcium antagonists with different pharmacological profiles, verapamil and amlodipine, on haemodynamics at rest and during exercise. SUBJECTS AND METHODS: Six healthy volunteers (aged 20-29 years) were randomly assigned to receive single oral doses of amlodipine (5 mg), slow-release verapamil (240 mg) or a placebo during a double-blind cross-over study. Systolic (SAP), diastolic and mean arterial pressures (measured using a cuff sphygmomanometer), heart rate (HR), cardiac index (CI, bioimpedance), rate-pressure product (SAP x HR), and noradrenaline and adrenaline plasma levels were measured at rest before drug administration, and at rest and during graded bicycle exercise (steps of 50, 100 and 150 W during 3, 3 and 4 min, respectively) started 3 h after drug administration. RESULTS: At rest arterial pressure, HR, rate-pressure product and catecholamine plasma levels did not change after verapamil or amlodipine administration, whereas CI significantly decreased after verapamil (from 3.9 +/- 0.4 to 3.3 +/- 0.4 l/min per m2) but not after amlodipine (3.9 +/- 0.3 and 4.1 +/- 0.5 l/m per m2) administration. During exercise the increases in SAP and HR were slightly but not significantly higher after amlodipine than after verapamil administration, rate-pressure product and CI were higher after amlodipine (22 +/- 1 x 10(3) mmHg x beats/min and 13 +/- 2 l/min per m2, respectively) than after verapamil (20 +/- 1 x 10(3) mmHg x beats/min and 10 +/- 2 l/min per m2, respectively) administration. Plasma levels of noradrenaline and adrenaline were similar at rest after each treatment and were slightly more increased after amlodipine administration during exercise. CONCLUSIONS: In contrast to amlodipine, verapamil induced a slight myocardial depressive effect at rest and did not potentiate the myocardial effects of the sympathetic stimulation induced by exercise. The myocardial action of verapamil is such as to induce some decrease in myocardial oxygen demand, both at rest and during exercise.

Adult↗
PubMed1992

Bioactive polymers: in vitro and in vivo study of controlled release neomycin.

Neomycin is coupled on xanthan-a polysaccharide of microbial biosynthesis produced by Xanthomonas campestris-through ionic complexation. The kinetics of neomycin release, in vitro, at pH = 8.2 is studied. A controlled release of neomycin, following a zero order kinetics is observed, regardless of the eluent flow. Neomycin complexed on xanthan, administered in a unique daily dose to patients suffering from dysentery in the 100 cases taken in study, has shown a high clinical efficiency as compared with the treatments with ampicillin or furazolidone, administered for 5-10 days or longer.

Adult↗
PubMedDate not supplied

[Role of endothelium-derived nitric oxide in sustained flow-dependent dilatation of human peripheral conduit arteries].

Endothelial dysfunction is involved in the pathogenesis of cardiovascular diseases and is generally associated to the decrease in arterial nitric oxide (NO) availability. In humans, endothelial function can be evaluated by the post-ischaemic flow-dependent dilatation (FDD) of peripheral conduit arteries which is mainly mediated by the NO release when short duration of reactive hyperaemia are used (3 to 5 min ischaemia). However, recent studies suggest that the role of NO in this response decreases as the duration of the hyperaemic stimulation increases. The aim of the present study was thus, to evaluate, in healthy subjects, the role of NO in the FDD of conduct arteries in response to a sustained stimulation. Radial artery diameter (echotracking) and flow (Doppler) were measured, 7 cm under the elbow line, at baseline and during post-ischaemic hyperaemia (10 min wrist cuff inflation) in 10 healthy subjects (age: 24 +/- 1 years) in control period and after acute blockade of the endothelial NO-synthase by local infusion of NG-monomethyl L-arginine (L-NMMA, brachial artery, 8 mumol/min, 7 min). Endothelium-independent dilatation was studied by mean of sodium nitroprusside infusion (SNP: 5, 10 and 20 nmol/min, 3 min each dose before and after L-NMMA). L-NMMA administration decreased radial artery blood flow at base (Control: 14 +/- 2 vs L-NMMA: 10 +/- 1 ml/min, P < 0.05) and increased radial artery vasodilatation in response to SNP (P < 0.05) thus, demonstrating NO-synthase inhibition. Therefore, after L-NMMA there was a small decrease in radial FDD (Control: base: 2.52 +/- 0.05 mm, FDD: 11.3 +/- 0.6% vs L-NMMA: base: 2.51 +/- 0.04 mm: FDD: 9.0 +/- 0.9%; p < 0.05) without change in hyperaemia. In conclusion, our results demonstrate, in contrast to those obtained after short duration of hyperaemia, that the relative implication of NO in the flow-dependent vasodilatation of peripheral conduit arteries in humans decreases in response to sustained stimulation and suggest, in these experimental conditions, an associated flow-dependent vasodilating mechanism that is unaffected by the NO-synthase inhibition.

Adult↗
PubMedDate not supplied

[Hand skin heating: a new method for the evaluation of conduit artery endothelial function in insulin-dependent diabetic patients].

The presence of an altered endothelium-mediated flow-dependent dilatation (FDD) of peripheral conduit arteries in insulin-dependent diabetic patients without microangiopathy is still controversial. We studied 10 normotensive and non atherosclerotic insulin-dependent diabetic patients (D group) without complication (neuropathy, microalbuminuria or neuropathy) and 10 control subjects (C group) matched for age, sex and BMI. Radial artery diameter (RAD, echotracking) and flow (RAF, Doppler) were measured at baseline and during FDD in response to distal hand skin heating (from 34 to 44 degrees C). a method developed to increase RAF by stable steps by decreasing gradually hand skin vascular resistance. Endothelium-independent dilatation was evaluated by administration of glyceryl trinitrate (GTN: 0.3 mg spray). At baseline, there was no difference between group for RAF (C: 18 +/- 5 vs D: 18 +/- 2 mL/min; NS) and RAD (C: 2.51 +/- 0.12 vs D: 2.54 +/- 0.07 mm; NS). Heating induced in the diabetic group a smaller increase in RAF (C: 473 +/- 126% vs D: 262 +/- 63%; p<0.05) and RAD (C: 22.6 +/- 2.6% vs D: 16.1 +/- 1.8%; p<0.01). This last result remains significant when the increase in RAF was included into the analysis of RAD variation during heating (p<0.05). GTN-induced dilatation was similar in the 2 groups. Our results obtained by use of the hand skin heating method demonstrate the presence of an abnormal arteriolar skin reactivity and an altered peripheral conduit artery endothelium-dependent dilatation in uncomplicated insulin-dependent diabetic patients. The early identification of these anomalies, with negative prognostic value, could contribute to the management of these patients.

Adult↗
PubMedDate not supplied

[Infectious endocarditis in mitral valve prolapse].

The paper reports on 13 cases of infectious endocarditis in the patients with prolapse of the mitral valve admitted for a period of 10 years (1979-1989) into the Clinic of Cardiology of the Fundeni Hospital. These cases stand for 3.6% of the cases with prolapse of the mitral valve admitted during that period, and 5% of the patients with infectious endocarditis. Our study dealt only with the cases of the prolapse of the mitral valve, clinically and echographically documented before the appearance of the septic graft. The hemocultures were positive in all the patients (viridans streptococci in 84.61% cases). The symptomatology, the clinical objective data and the paraclinical results (phonocardiographic, echocardiographic, electrocardiographic, radiologic, investigations with isotopes), the response to the treatment (medical, surgical) and the evolution in time were analyzed. An increase was found during endocarditis in the number of patients with holosystolic murmurs (30.7% cases) versus those with click-telesystolic murmur, the appearance in 41.15% of the cases of valvular vegetations at the Echo examination, and in 15.38% cases of ruptures of cordages. Mitral insufficiency secondary to endocarditis became worse, in 30.76% cases. The treatment with antibiotics resulted in the healing of the infection in all the cases. The surgery was not necessary in any patient during the evolution of endocarditis. The surgery (valvular prosthesis) was made in 23.07% cases, which presented, after curing the septic graft, important mitral regurgitation with cardiac insufficiency refractory to the medical treatment. Prophylaxis of the infectious endocarditis in the prolapse of mitral valve with mitral regurgitation is necessary.

Adult↗
PubMedDate not supplied

[An experimental model of data base organization in glaucoma with computer processing (a preliminary note)].

The authors report on an experimental model of data base set up for glaucoma with possibilities of statistical-mathematical processing. The application is designed for miniprocessors of the INDEPENDENT or CORAL type in FORTRAN 77. The paper presents the level structure of the display, and the ways of using the information under the form of assisted diagnosis and prognosis, according to which the attention is then directed to the rhythm and detailed content of the future examination.

Computer Systems↗
PubMedDate not supplied

Anatomoclinical correlations in coronary heart disease: recent advances and unanswered questions.

An attempt is made to summarize the recent available information on anatomoclinical correlations in coronary heart disease. The paper focuses attention on: (a) the role in the pathogenesis of unstable angina pectoris, severe arrhythmias and sudden cardiac death, of repeated cycles of formation, disintegration and peripheral embolization of intramural thrombi or of thrombi developed on preexisting atherosclerotic plaques; (b) a still apparently unsolved problem: which comes first, coronary thrombosis or myocardial infarction? (c) the pathophysiological and clinical significance of the "border zone" of myocardial infarcts; (d) the importance, in the pathogenesis of coronary heart disease and particularly of sudden cardiac death, of obstructive lesions which occur in the vessels supplying the conduction system of the heart.

Angina Pectoris↗