Biomedical subjects

G Matos

Publications and source records attributed to G Matos.

6 recordsLinked to original sources

PubMed2005

Treatment of unprotected left main coronary artery stenosis with a drug eluting stent in a heart transplant patient with allograft vasculopathy.

High risk angioplasty with drug eluting stent placement into an unprotected left main coronary artery in a heart transplant recipient with allograft vasculopathy is reported. Ten month angiographic follow up is reported. The literature is reviewed and current methods of revascularisation are described in detail. This is the first report of drug eluting stent use in this clinical situation.

Coronary Restenosis↗

PubMed1997

Infiltrator Angioplasty Balloon Catheter: a device for combined angioplasty and intramural site-specific treatment.

OBJECTIVES: We describe a new angioplasty device (Infiltrator Angioplasty Balloon Catheter; IABC) with intramural drug delivery capability. The conventional balloon part of the device, when inflated, dilates the vessel or has three rows of longitudinally mounted infiltrator nipples to penetrate the tunica media. Through an independent infiltrator port and nipples, drugs can be infiltrated directly into the vessel wall. METHODS: The device was tested in 117 normal coronary arteries of 58 farm pigs. RESULTS: (1) The infiltration procedure does not damage the vessel angiographically or histologically. At the infiltration site, the endothelial layer and the internal elastic lamina has a controlled interruption, and the infiltrated fluid is distributed among the medial layers, causing a mild focal edema and medial thickening (1.8 times on average). (2) Rhodamine tracer is circularly and evenly distributed through the whole width of the vessel wall within 10 min after infiltration. (3) Two weeks after the infiltration procedure, the medial layer reveals mild local thickening and remodelling without luminal narrowing. (4) Of the intramurally infiltrated Tcm99-labeled surfurcolloid, 83.8% is detectable at 5 min after the delivery procedure by gamma camera. (5) The IABC, if oversized, is able to achieve angiographic dilatation in normal pig coronary arteries, causing histologic damage similar to or less than that induced by conventional balloon dilatation. CONCLUSIONS: The IABC can deliver fluid-phase substances directly into the vessel wall with microliter accuracy and with 90% efficiency without significant acute and subacute damage to the vessel wall. It is also suitable for combined dilatation and local drug delivery.

Angioplasty, Balloon, Coronary↗

PubMed1996

Effects of bisaramil on coronary-occlusion-reperfusion injury and free-radical-induced reactions.

The aim of this study was to determine whether bisaramil-an antiarrhythmic compound under clinical investigation-influences the reperfusion-induced arrhythmias and biochemical parameters characterizing occlusion-reperfusion-induced free-radical reactions. The left descending coronary artery (LAD) was occluded for 60 min in anaesthetized dogs followed by one hour of reperfusion. Blood samples were taken at different times of the occlusion and reperfusion for the determination of plasma concentration of malondialdehyde (MDA), reduced (GSH) and oxidized glutathione (GSSG); furthermore of the activity of catalase and superoxide dismutase (SOD). Free-radical generating capacity of polymorph neutrophil granulocytes (PMN) was also measured. At the end of the experiments heart tissue samples were excised from the injured areas and from the intact part of the left ventricular muscle. In tissues samples the concentrations of MDA and GSH and the activity of SOD were determined. Bisaramil was given as an i.v. bolus injection at a dose of 2 mg kg-1 several minutes prior to the end of LAD-occlusion; then the administration was repeated in the 30th minute of reperfusion. In the control group (10 dogs) ventricular fibrillation (VF) occurred in seven cases which resulted in death in three. In the bisaramil-treated group, however. VF was seen in three cases and no death was recorded. Bisaramil inhibited the elevation of the plasma concentration of MDA and GSSG during the reperfusion and abolished the decrease in the plasma concentration of GSH during the occlusion and reperfusion. The activity of SOD and catalase in plasma was much better preserved in the bisaramil-treated group then in the controls. Bisaramil significantly inhibited the increase of the superoxide-radical generating capacity of PMNs during the reperfusion. The data obtained from myocardial tissue samples supported the cardioprotective effect of bisaramil. The biochemical investigation of ischemic-reperfused myocardium showed that bisaramil promoted preservation of SOD-activity and of tissue glutathione. Results of this study clearly showed that bisaramil has a significant effect on ischemiareperfusion injury. Besides its inhibitory effects on ischaemia-reperfusion induced arrhythmias it has a special benefit in influencing free-radical mediated damage leading to better preservation of membranes and to limitations of irreversible cell injuries.

Animals↗

PubMed1995

Influence of the beta-blocker therapy on neutrophil superoxide generation and platelet aggregation in experimental myocardial ischemia and reflow.

The beneficial effect of beta-blockade has been reported in acute myocardial ischemia as well as in the postinfarction period. Recent interest focused on the special effect of beta-blocking agents regarding the changes of lipid metabolism, free radical mediated reactions and arachidonic acid cascade. In previous experiments on dogs we have shown that ultrashort-acting beta-blocker (Brevibloc) could modify production of prostacyclin and thromboxane in ischemic heart tissue. The purpose of this study was to investigate the effect of Brevibloc on the function of isolated neutrophils and platelets during myocardial ischemia and reperfusion. In mongrel dogs the left descending coronary artery (LAD) was ligated for 1 or 2 hours followed by one hour reperfusion. Animals were divided into two groups: Group I control dogs (n = 21) no drugs were given; in Group II. (n = 20) short half-life beta-blocker esmolol HCl (Brevibloc) was administered intravenously. Polymorphonuclear leukocytes (PMN) were isolated from venous blood before and after LAD ligature and following reperfusion. Spontaneous and phorbol myrystate acetate (PMA) stimulated superoxide radical generation of isolated PMN was measured. Platelets were separated at the same periods and maximal aggregation was determined in platelet rich plasma (PRP) after stimulation with collagen, adrenaline and ADP. There was no spontaneous radical production of PMN neither in the control, nor in the Brevibloc treated animals. Neutrophil superoxide production after activation in Group I was 9.54 +/- 0.3 O2-/min/1.5 x 10(6) before LAD ligature, and significant elevation was present following one hour reperfusion (14.8 +/- 0.8 O2-/min/1.5 x 10(6)). Increased production of neutrophils was inhibited by beta-blocker therapy (9.32 +/- 1.05, 8.25 +/- 0.82 respectively). Collagen and ADP stimulated platelet aggregation increased more than 20% during ischemia in Group I, which elevated further after reperfusion. Administration of Brevibloc diminished maximal aggregation in both cases, after 1-2 hours of LAD ligature and after reperfusion, compared to the initial value. Our findings suggested that ultrashort-acting beta-blocker has in vivo inhibitory action on neutrophil superoxide generation and platelet aggregation influencing the pathological cellular interactions.

Adrenergic beta-Antagonists↗

PubMed1992

Prevalence of HTLV infection in the Dominican Republic: association with neurological disease.

The presence of the human T-cell leukemia virus (HTLV) in Dominican blood donors and patients with tropical spastic paraparesis (TSP) was first detected in 1987. To define further the seroprevalence in the country, nearly 4,000 samples from high- and low-risk populations, as well as patients with neurological disease and with leukemia or lymphoma were tested for HTLV antibodies. A 1-2% seropositivity rate was found among the low-risk population, a 2-5% in the high-risk, and at least 87% in those with TSP. A few patients with malignancy also had antibodies to HTLV. An increase in seropositivity with age and a predominance of female seropositive individuals were found. Infectious virus was isolated from TSP patients, prostitutes, and family members of index patients. These data indicate the substantial level of HTLV infection in another Caribbean country and its relation to neurologic disease.

Adolescent↗

PubMed1992

Computerized tomography versus magnetic resonance imaging: a comparative study in hypothalamic-pituitary and parasellar pathology.

OBJECTIVE: We wished to analyse the relative value of computerized tomography and magnetic resonance in patients referred for evaluation of pituitary and parasellar lesions. DESIGN: We performed a separate evaluation by two independent neuroradiologists of computerized tomography and magnetic resonance images ordered numerically and anonymously, with no clinical data available. PATIENTS: We studied 40 patients submitted for hypothalamic-pituitary study; 31 were carried out preoperatively, of which histological confirmation later became available in 14. The remaining nine patients were evaluated postoperatively. MEASUREMENTS: Over 40 parameters relating to the bony margins, cavernous sinuses, carotid arteries, optic chiasm, suprasellar cisterns, pituitary, pituitary stalk and extension of the lesion were evaluated. These reports were compared with the initial ones offered when the scans were ordered, and with the final diagnosis. RESULTS: Concordance between initial computerized tomography and magnetic resonance was observed in 27 cases (67.5%); among the discordant cases computerized tomography showed the lesion in two, magnetic resonance in 10, while in the remaining case reported to harbour a microadenoma on computerized tomography the differential diagnosis between a true TSH-secreting microadenoma and pituitary resistance to thyroid hormones is still unclear. Both neuroradiologists coincided in their reports in 32 patients (80%); when the initial report was compared with those of the neuroradiologists, concordance was observed with at least one of them in 34 instances (85%). Discordant results were observed principally in microadenomas secreting ACTH or PRL and in delayed puberty. In the eight patients with Cushing's disease (histologically confirmed in six) magnetic resonance was positive in five and computerized tomography in two; the abnormal image correctly identified the side of the lesion at surgery. CONCLUSIONS: In patients referred for evaluation of Cushing's syndrome or hyperprolactinaemia (due to microadenomas) or after surgery, magnetic resonance is clearly preferable to computerized tomography. In macroadenomas both scans are equally diagnostic but magnetic resonance offers more information on pituitary morphology and neighbouring structures. Nevertheless, there are cases in which the results of computerized tomography and magnetic resonance will complement each other, since different parameters are analysed with each examination and discordant results are encountered.

Adenoma↗