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Biomedical subjects

P A Jorge

Publications and source records attributed to P A Jorge.

At least 19 recordsLinked to original sources
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↗
PubMed1979

Sequence of shortening of the normal human left ventricle.

Left ventricular sequence of shortening was studied through the analysis of cineventriculograms in 30 degree right anterior oblique projection of 11 normal patients. In all patients transverse shortening progressed in base to apex direction, in a concentric fashion. Base descent started simultaneously with the first transverse inward motion and continued throughout systole. There was a slight protrusion of the apex in the beginning of systole, lasting a mean of 115 ms.

Adolescent↗