Search PubMed⌕ Search

Biomedical subjects

P A Jorge

Publications and source records attributed to P A Jorge.

At least 19 recordsLinked to original sources
PubMed1998

[Effect of eggplant on plasma lipid levels, lipidic peroxidation and reversion of endothelial dysfunction in experimental hypercholesterolemia].

PURPOSE: To study the effect of egg plant on endothelium-dependent relaxation, and plasma lipids in hypercholesterolemic rabbits, and to assess influence of this plant on the malondialdehyde (MDA) content of LDL particles and the arterial wall. METHODS: Thirteen male rabbits were randomly assigned to control (C), hypercholesterolemic (H) and egg plant (E) treated groups (n = 10 each). The H and E rabbits were fed a diet supplemented with cholesterol (0.5%) and coconut oil (10%) for 4 weeks. In addition, group E received 10 mL of the fruit juice/day during the last 2 weeks. The animals were killed and the aorta removed to measure MDA content and the endothelium dependent relaxation responses. Total plasma cholesterol, VLDL, LDL, HDL and triglyceride levels were determined using commercial kits. MDA was quantified in native and oxidized LDL and in the arterial wall. RESULTS: After 4 weeks, the E group rabbits had a significantly lower weight, plasma cholesterol, LDL, triglyceride and aortic cholesterol content than group H(p < 0.05). The MDA content that was significantly increased in the LDL particles and in the arterial wall of H rabbits was reduced in the E group (p < 0.05). Endothelium-dependent relaxation were significantly higher in the E group compared H group rabbits (p < 0.05). CONCLUSION: In hypercholesterolemic rabbits egg plant juice significantly reduced weight, plasma cholesterol levels, aortic cholesterol content and the MDA concentrations in native-oxidized LDL and in the arterial wall and increased the endothelium-dependent relaxations.

Animals↗
PubMed1997

Endothelium-dependent coronary flow in ischemia reperfusion.

The aim of the present report was to study the effect of ischemia-reperfusion on the endothelial cell function of coronary vessels. Twelve adult male dogs were instrumented for the measurement of aortic and left ventricular pressures, heart rate and coronary blood flow. The left anterior descending coronary artery was occluded for 90 minutes followed by 20 minutes of reperfusion. Acetylcholine was infused into the coronary artery at a rate of 15 micrograms/kg/min. Coronary flow, heart rate and aortic and left ventricular pressures were registered during the pre-occlusion period and after 20 minutes of reperfusion under basal conditions, as well as during acetylcholine administration. These same parameters were also measured during reactive hyperemia following vessel deocclusion. Acetylcholine produced a 155% increasing coronary flow during the pre-occlusion period (p < 0.05). In the reperfusion period, no statistically significant difference was observed between the flows in the presence and absence of this substance, nor were there any differences in the other cardiovascular parameters monitored. Triphenyltetrazolium staining confirmed myocardial infarction in all the hearts examined. The authors conclude that reperfusion following myocardial infarction prevents the increasing in coronary flow in response to acetylcholine as a result of endothelial dysfunction in the resistance coronary vessels.

Acetylcholine↗
PubMed1997

Rapid reversal of endothelial dysfunction in hypercholesterolaemic rabbits treated with simvastatin and pravastatin.

1. The main objective of the present study was to verify the speed with which two 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, simvastatin and pravastatin, could revert endothelial cell dysfunction in hypercholesterolaemic rabbits. An attempt was also made to correlate the plasma cholesterol level and the tissue cholesterol and malondialdehyde (MDA) contents of the aortae with the endothelium-dependent relaxation on the assumption that any endothelial dysfunction could be rapidly and partially reversed, even in the presence of relatively high serum cholesterol levels. 2. Ninety-one male New Zealand white rabbits were randomly assigned to hypercholesterolaemic (control), simvastatin or pravastatin groups. All rabbits were fed a diet supplemented with cholesterol (0.5%) and coconut oil (2%) for 8 weeks. Simvastatin (10 and 20 mg/day) and pravastatin (15 and 30 mg/day) were administered 6, 4 and 2 days before the end of the experiment. At the end of the 8th week, animals were killed and the aortae were removed for histological examination as well as for the measurement of cholesterol and MDA contents and for endothelium-dependent relaxation studies. 3. The results showed that significant improvement in endothelium-dependent relaxation was obtained only with pravastatin and only with 4 or 6 days of administration. In these cases, the cholesterol and MDA contents of the vessel wall were reduced, although no significant changes were observed in plasma total cholesterol. Higher doses of the drugs did not alter these results. 4. We conclude that pravastatin enhances endothelium-dependent relaxation when administered to cholesterol-fed rabbits, probably via an anti-oxidant action. This effect, which was observed to start on the 4th day of drug administration, may represent a new therapeutic approach for the treatment of acute coronary syndromes in hypercholesterolaemic patients.

Animals↗
PubMed1997

[Effects of omega-3 acids on endothelium-dependent relaxation in hypercholesterolemic rabbits].

PURPOSE: To study the effect of omega-3 fatty acid on endothelium-dependent relaxation, total plasma cholesterol, LDL-cholesterol, HDL-cholesterol and triglycerides levels as well as, the malondialdehyde (MDA) content of the LDL particles and arterial wall. METHODS: Fourteen male rabbits were randomly assigned to hypercholesterolemic and omega-3 groups. The dose of omega-3 fatty acid utilized was 300g/kg/day during 15 days. All rabbits were fed a diet supplemented with cholesterol (0.5%) and coconut oil (2%) for four weeks. At the end of the experiment the animals were killed and the aorta removed for measurement of MDA content and the endothelium-dependent relaxation studies. Total plasma cholesterol, VLDL-cholesterol, LDL-cholesterol, HDL-cholesterol and triglycerides was measured by enzymatic kits. MDA was also measured in natives and oxidized LDL and arterial wall. RESULTS: Cholesterol and VLDL-cholesterol were increased significantly in the omega-3 treated animals. The triglyceride level was significantly reduced (p < 0.05). The MDA content was increased in the LDL particles and in the arterial wall (p < 0.05). Endothelium-dependent relaxation was significantly reduced (p < 0.05). CONCLUSION: Omega-3 fatty acid impairs the endothelium-dependent relaxation when administered to cholesterol fed rabbits, increases the cholesterol and reduces the triglycerides plasma levels. The lipid peroxidation of the LDL particles and arterial wall was increased.

Animals↗
PubMed1996

Effects of vitamin E on endothelium-dependent coronary flow in hypercholesterolemic dogs.

The authors studied the effect of vitamin E on endothelium-dependent coronary flow in hypercholesterolemic dogs. Adult mongrel dogs weighing 7.4 +/- 1.0 kg were divided into control, hypercholesterolemic and vitamin E groups. The animals in the hypercholesterolemic group were fed a diet enriched with cholesterol (5% w/w) and coconut oil (10% w/w) for 40 days. The vitamin E group received the same diet plus 400 IU of vitamin E during the last 15 days of the experiment. Total serum cholesterol levels were evaluated at the beginning and at the end of the experiment using a commercial enzyme kit and a Beckman analyzer. The coronary flow was determined by electromagnetic flowmetry using a probe positioned in the left anterior descending coronary artery, near the ostium. A needle connected to a perfusion pump was introduced into the coronary artery for the administration of acetylcholine and sodium nitroprusside at a rate of 5 micrograms/kg per min. The aorta was cannulated for the measurement of arterial blood pressure via a pressure transducer coupled to a Siemens multi-channel recorder. The tissue cholesterol content and malonic dialdehyde (MDA) were also measured in isolated coronary vessel specimens. At the end of 40 days, the serum cholesterol levels had increased by 226% and 190% in the hypercholesterolemic and vitamin E groups, respectively. However, the difference in the levels of these two groups was not significant (P > 0.05). The aortic blood pressure and heart rate remained unchanged during acetylcholine administration. In contrast, systolic and diastolic pressure fell and the heart rate increased during the infusion of sodium nitroprusside. The tissue cholesterol content and MDA were significantly (P < 0.05) increased in coronary artery specimens from the hypercholesterolemic compared to control animals. Vitamin E was able to reduce these increases in cholesterol treated animals (P < 0.05). The percent change in coronary flow during acetylcholine administration was significantly lower in the hypercholesterolemic group when compared with control animals (P < 0.05) but was unaltered in the vitamin E group (P > 0.05). During sodium nitroprusside administration, the coronary flow increased in the vitamin E group (P < 0.05). The authors conclude that hypercholesterolemia reduces endothelium-dependent coronary flow and increases the tissue cholesterol content and MDA of coronary arteries. Vitamin E decreases the MDA and the tissue cholesterol content without significantly affecting the total serum cholesterol level. Vitamin E may thus restore coronary flow by reverting endothelial dysfunction.

Acetylcholine↗
PubMed1994

Effects of simvastatin and pravastatin on endothelium-dependent relaxation in hypercholesterolemic rabbits.

OBJECTIVES: The present study was conducted to investigate endothelium-dependent relaxation in hypercholesterolemic rabbits after treatment with two HMG-CoA reductase inhibitors: Simvastatin and Pravastatin. METHODS: Thirty male New Zealand rabbits were randomly assigned to Control, Simvastatin and Pravastatin groups and fed a diet supplemented with lipids and cholesterol (coconut oil 10% and cholesterol 1%) for 8 weeks. The drugs were administered in dosages of 10 mg/kg from the fourth to seventh weeks; at the end of the seventh week, plasma cholesterol was determined, and the Pravastatin dosage adjusted to 15 mg/kg to obtain similar levels of plasma cholesterol for the two experimental groups. At the end of the 8th week, the animals were killed and aorta removed for histologic examination and the measurement of cholesterol content, as well as for the conduction of endothelium-dependent relaxation studies. RESULTS: At the end of the study serum cholesterol was reduced by 57.1% in the Pravastatin group and 58.4% in the Simvastatin group, with the aortic cholesterol content in the former being significantly lower than that of the Simvastatin and Control groups (p < 0.05). Histologic examination also revealed a significant decrease in volume fractions of foam cells in Pravastatin-treated animals, whereas endothelium-dependent relaxation in response to ACh was significantly impaired in the Simvastatin group. No significant difference was found in relaxation induced by nitroprusside. CONCLUSIONS: In spite of the similar reduction in plasma cholesterol obtained by different doses, it seems that Pravastatin preserves the endothelium-dependent relaxation of aortic rings of hypercholesterolemic rabbits more effectively than does Simvastatin.

Acetylcholine↗
PubMed1991

[Coronary microcirculation in myocardial reperfusion. The phenomenon of no-reperfusion].

PURPOSE: The study of the ultrastructural features of the coronary microvessels in postischemic reperfusion. MATERIAL AND METHODS: Five mongrel dogs of either sex, weighing 2 to 17 kg were studied Each dog was anesthetized with 30 mg. of pentobarbital and ventilated with room air. A thoracotomy was done and the left descendent coronary artery was isolated. Aorta and right atria pressures, electrocardiogram and coronary blood flow was measured. After 90 minutes of coronary occlusion and 20 minutes of reperfusion carbon black was injected into the anterior descending coronary artery to identify the area of impaired perfusion. The heart was excised and placed in a ice-cold saline. The left ventricle was cut transversely in six slices of 1 cm thickness parallel to the atrioventricular sulcus. Tissue specimens were taken from the subendocardial, mid-myocardial (in the non reperfused area) subepicardial and control layers for electron microscopic examination. Each slice was then incubated in a 1% solution of triphenyltetrazolium chloride (TTC) at 37 degrees C for 10 minutes. RESULTS: The infarcted areas showed widespread tissue damage with relaxed myofibrils cellular edema, swollen mitochondria with fractured cristae and nuclear changes. The vascular endothelium demonstrated severe injury with edema, cytoplasmic clearing, loss of pinocytotic vesicles, nuclear changes, formation of blebs into the vascular lumen and intravascular neutrophil. In the mid-myocardial layer, near the non reperfused vessels, a striking contrast was observed between the vessel and myocardium cells patterns. The usual picture was a severe vascular damage without myocyte injury. CONCLUSION: This study showed that prominent capillary damage with coagulation necrosis was the morphologic pattern observed in areas of myocardial infarction. In the mid-myocardium, near the non reperfused vessel, severe capillary damage was found in areas of preserved myocytes. Obstruction of flow at the capillary level, correlates well with the decrease of the coronary flow reserve observed during the post-ischemic reperfusion.

Animals↗
PubMed1990

[The coronary flow reserve during reperfusion in myocardial infarction].

PURPOSE: The study of coronary flow reserve on the reperfused myocardium damaged by 90 minutes of severe ischemia. MATERIAL AND METHODS: Nine mongrel dogs of either sex, weighing 12 to 17 kg were studied. Each dog was anesthesiated with 30 mg of pentobarbital and ventilated with room air. A thoracotomy was done and the left descendent coronary artery was isolated. Aorta and right atria pressures was measured using a Siemmens-Elema transducers and mingograf recording-804 (Siemmens Instruments). Coronary blood flow was measures with a Caroline Medical Electromagnetic flowmeter, 501D. The index studied was the coronary resistance, calculated as the quotient of the diastolic aortic pressure and the diastolic blood flow. The coronary reserve was studied during reactive hyperemia produced by 10 seconds of coronary occlusion in the 5, 10, 15 and 20 minutes of reperfusion. The infarcted area was detected by TTC (triphenyltetrazolium) method. RESULTS: All the hearts examined showed infarcted area. The diastolic coronary resistance during the reactive hyperemia in the 20 minutes of reperfusion was higher than the control value. CONCLUSION: The coronary vascular reserve was decreased during reperfusion, in the myocardial infarction.

Animals↗
PubMed1990

[Significance of intramural vascular injuries in myocardial revascularization. A case report].

The authors report the case of 59 year-old hypertensive woman, suffering from angina pectoris, who died 24 hours after coronary by pass surgery due to cardiogenic shock. Autopsy revealed a small recent postero-lateral infarction. The venous by pass, however, were inconspicuous. Histologic examination showed extensive microarteriopathy with stenosing intimal fibro-elastosis and hyperplasia of the media, affecting 73% of the vessels with a diameter greater than 150 micra. The authors believe that the diffuse microangiopathy could have affected the myocardial reperfusion, and participated of the mechanical dysfunction.

Angina Pectoris↗
PubMed1990

[Coronary flow reserve during myocardial reperfusion, after 15 minutes of ischemia].

PURPOSE: To study the coronary resistance reserve on the reperfused myocardium, damaged by 15 minutes of severe ischemia. MATERIAL AND METHODS: Eight mongrel dogs, of either sex, weighing 14.4 to 21 kg were used. The index studied was the late diastolic coronary resistance. The coronary reserve was studied through reactive hyperemia produced by 10 seconds of coronary occlusion in the 5, 10, 15 and 20 minutes of reperfusion. Histological studies were done in the reperfused and control areas. RESULTS: The myocardial structure in the reperfused area was essentially normal, without any lesion on the capillaries or intra-myocardial vessels. The diastolic coronary resistance, after reactive hyperemia, during the reperfusion 20 minutes, have no differences with the control values. The coronary resistances in the reperfusion time, improved progressively until normal control, considering the perfusion pressure. CONCLUSION: The coronary vascular reserve is preserved after 15 minutes of ischemia, followed by 20 minutes of reperfusion, considering the perfusion pressure.

Animals↗
PubMed1989

[Histologic aspects of intramyocardial arterioles, during drug induced vasodilation and vasoconstriction].

The author studied the histologic features of the intramyocardial arterioles of the dog, under various situations of vasomotricity induced by drugs. Hemodynamics were evaluated by the pressures of the right atria and the aorta and through the coronary flow. The histologic studies were done on biopsy specimens taken from the anterior left ventricular wall. The results were 1.1 (0.7-1.3) for the control state, 0.3 (0.1-0.6) for situations of vasodilatation and 1.5 (1.1-1.8) during vasoconstriction. The authors believe that the histologic appearance of the intramyocardial vessels, in the various situations of vasomotricity may represent the lower and upper limits of the autoregulatory curve.

Animals↗
PubMed1989

[Adrenergic coronary vasoconstriction during myocardial hypoperfusion].

The intramural branches of the coronary arteries of dogs were studied using venilite casts. The intramyocardial vessels have a general pattern with straight branches that cross from the epicardium toward the endocardium. Many branches were observed throughout the extension of these vessels, mainly in the subendocardium, where there is a rich interconnecting plexus. Some branches divides immediately in the subepicardium. These anatomic findings concur with the observations that the subendocardium is more susceptible to ischemia, as it is dependent on an extensive vascularization. These anatomic findings indicate that during constant underperfusion, the alpha adrenergically mediated vasoconstriction of the subepicardial vessels have an unexpected beneficial effect because of decreased transmural steal.

Animals↗
PubMed1989

[Ischemic cardiopathy with normal epicardial coronary arteries. Probable spasm of the coronary arteries. A case report].

The authors discuss the case of a young woman, with chest pain at rest and normal coronary arteries. Sixty-three days after the onset of the symptoms the patient had a myocardial infarction. The coronariogram showed obstruction of the left coronary artery in its full length. The authors consider that a coronary spasm was the cause of the infarction. It is very likely that independent of personal characteristics, coronary spasm may be persistent, involve the whole extent of the vessel and occur even with use of vasodilator drugs.

Adult↗