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F A Simeone

Publications and source records attributed to F A Simeone.

At least 55 records · Page 3Linked to original sources
PubMed1982

Qualitative measurement of cerebral infarction using ultraviolet fluorescence.

A reliable method of macroscopically determining the volume of cerebral infarction using ultraviolet fluorescence was developed in an animal model. Cerebral infarction was induced in 40 dogs by occluding the distal internal carotid and middle cerebral arteries. No barbiturates were administered. Intravenous sodium fluorescein was given before the animal was killed. Following fixation, 1 cm coronal sections were evaluated with ultraviolet light of 366 nm wavelength. The area of induced fluorescence for each section was determined using a grid overlay. Microscopic examination revealed that the areas of ischemic cell necrosis corresponded to areas of maximal fluorescence. This is an easily reproducible method to determine the volume of cerebral infarction.

Animals↗
PubMed1982

Arterial obstruction and ocular neovascularization.

A series of 12 patients (13 eyes) with neovascular glaucoma in association with arterial obstructive disease is presented. Appropriately characterized as having an ocular ischemic syndrome, the anterior segment findings in each included aqueous flare and rubeosis iridis. Posterior segment manifestations included midperipheral intraretinal hemorrhages (venous stasis retinopathy), narrowed retinal arteries, often a cherry red spot, and neovascularization of the disc and/or retina. Most eyes with the ocular ischemic syndrome have either ipsilateral common carotid artery obstruction or severe bilateral obstruction of the internal carotid arteries.

Aged↗
PubMed1982

Failure of intravascular volume expansion without hemodilution to elevate cortical blood flow in region of experimental focal ischemia.

Cerebrovascular and cardiac alterations evoked by intravascular volume expansion with whole blood, a popular adjunct in the clinical prevention or therapy of the focal ischemic deficits of cerebral vasospasm and acute stroke, were studied in splenectomized dogs. Clipping of the right distal internal carotid and proximal middle cerebral arteries in eight dogs reduced regional cortical blood flow (rCoBF) by 49% to 58% without altering cardiac output (CO), and produced about 10% hemispheric infarction. Eight dogs underwent similar cerebral arterial occlusion and eight dogs underwent arterial manipulation without clipping. Both latter groups received two autologous whole blood infusions within 2 hours, each equal to 20% of the respective dog's total blood volume. Despite significant CO elevations after the infusions, rCoBF in the middle cerebral arterial territory did not rise. These whole-blood infusions did not significantly alter mean arterial blood pressure, hematocrit, intracranial pressure, or, in dogs with clipped cerebral arteries, the relative size of infarction. These data suggest that nondilutional hypervolemia neither elevates collateral perfusion to ischemic regions of the brain nor reduces infarction. In addition, elevations in CO do not appear to augment blood flow in either ischemic or normal brain.

Animals↗
PubMed1982

Effect of extracranial-intracranial bypass and pentobarbital on acute stroke in dogs.

Ninety-three mongrel dogs underwent intracranial carotid and middle cerebral artery occlusions. They were then randomized into four groups: 1) the untreated control group (no surgical or medical therapy) showed significant neurological deficit, 16% mortality, and 17% mean hemisphere infarction; 2) in the bypass group (superficial temporal to middle cerebral artery (STA-MCA) anastomosis completed within 3 hours of occlusion), neurological deficit was diminished, mortality was 7%, and mean infarction 5.66%; 3) in the pentobarbital group (single dose of pentobarbital, 35 mg/kg administered intravenously 30 minutes after occlusion), neurological deficit was essentially the same as in the previous group, there was no mortality, and mean infarction was 5.52%; and 4) in the pentabarbital/bypass group (pentabarbital dose plus STA-MCA bypass), neurological deficit was slightly lower than in previous treatment groups, there was no mortality , and mean hemisphere infarction was 1.78%. Extracranial-intracranial bypass produced an immediate 31.6% increase in regional cortical blood flow. The combination of pentobarbital postocclusive therapy and early extracranial-intracranial bypass beneficial synergism.

Animals↗
PubMed1982

Pentobarbital changes compartmental contribution to cerebral blood flow.

Barbiturates were administered to normal dogs, establishing an isoelectric electrocorticogram. Cortical cerebral blood flows (CBF) and deeper CBF's were respectively measured by krypton-85 (85Kr) and xenon-133 (133 Xe). Following barbiturate administration, the two methods of measuring CBF showed a poor coefficient of variation (r=0.12, p less than 0.05). The cortical flows decreased less than the fast compartment flows. A shifting of percentage contribution of flow to the slow compartment (60% increase, p less than 0.001) was observed after barbiturate infusion. A selective shunting of blood flow to the slower areas may explain the lowering of intracranial pressure and protection of the deep white matter observed by many authors who use barbiturates in clinical an experimental situations.

Animals↗
PubMed1980

Effects of 2-ethylamino-1,3,4-thiadiazole on hepatic adenosine nucleotides in experimental hemorrhagic shock.

2-Ethylamino-1,3,4-thiadiazole (EAT), originally tested as a cancer chemotherapeutic agent, has been shown to increase the de novo synthesis of purines. To evaluate its effects on hepatic adenosine nucleotides in hemorrhagic shock, EAT was administered to dogs prior to bleeding. Concentrations of uric acid and allantoin in serum and lymph were also measured as additional indices of purine metabolism in the dog. During oligemia, the adenosine triphosphate (ATP) in serial liver biopsies fell to half of the control values in treated and untreated groups. After reinfusion, the APT and total adenosine nucleotides increased in both groups but were significantly higher in treated than in untreated control animals (P less than 0.05). In treated animals the hepatic ATP reached 93% and 109% of initial values at one and three hours after reinfusion, respectively. Corresponding values were 63% and 80% in surviving untreated control animals. During oligemia and after reinfusion, the uric acid was increased in both groups but remained significantly lower in treated than in untreated animals. The arterial pressure of treated animals remained higher after reinfusion than in untreated animals. Studies in oligemic rats demonstrated significantly greater survival in EAT-treated animals than in untreated controls. The data suggest that pretreatment with EAT results in improved recovery of the hepatic adenosine nucleotide pool and increased survival of oligemic animals, which may be related to the greater availability of substrates for synthesis of the adenosine nucleotides.

Adenine Nucleotides↗
PubMed1978

The Grimonster symposium on the occasion of the 50th anniversary of the first lumbar sympathectomy.

Under the auspices of the Belgian Surgical Society, a small group of American and European surgeons discussed in detail the place of lumbar sympathectomy in present day surgical practice. A consensus was reached concerning the physiologic effect, anatomical variations and indications for the operation. Conclusions included the questionable value of lumbar sympathectomy for treating intermittent claudication due to aortoiliac disease alone, its possible effectiveness when obliterative arterial disease is limited to the femoral popliteal segment, and its occasional beneficial effect when performed in conjunction with some reconstructive arterial operations.

Belgium↗
PubMed1978

Vascular complications of upper cervical spine injuries.

Upper cervical spine injuries can be complicated by occlusion of the vertebral and carotid arteries. Injury to the former is more common. The arteries may be kinked or temporarily occluded, in which case the symptoms are transient. With more forceful trauma, damage to the intima and subsequent thrombosis or prolonged spasm may ensue. Early recognition of ischemic symptoms hastens the diagnosis. In most instances it is not possible to alter advanced neurologic deficits once they are established.

Adult↗
PubMed1977

The treatment of patients with recurrent ventricular fibrillation.

During the four year period from 1972 to 1975, eleven patients, eight with recurrent and three with first attacks of ventricular fibrillation, underwent aortocoronary bypass graft and/or resection of ventricular aneurysm. All patients had old myocardial infarction from seven weeks to six years. Left ventricular angiography demonstrated discrete aneurysm of the anterior wall of the left ventricle in nine of the patients and akinesis or hypokinesis of the anterior and posterior wall of the left ventricle in the remaining two. Coronary angiography was carried out in ten patients and revealed significant disease of the left anterior descending and right coronary arteries in ten and nine patients, respectively. There was no operative mortality, and there were two late deaths. Eight patients have improved significantly and have had no further sign of ventricular irritability. The present study indicates that aortocoronary bypass graft and/or resection of ventricular aneurysm is an effective method of therapy for patients with repeacted ventricular fibrillation who have ventricular aneurysm and ischemic heart disease.

Adult↗
PubMed1977

The lumbar sympathetic. Anatomy and surgical implications.

The ganglionated lumbar sympathetic chains lie on the lateral aspects of the bodies of the lumbar vertebrae and not more laterally as in the thorax where the chain lies in relation to the heads and necks of the ribs. Lumbar ganglia vary in number. They are best numbered according to the spinal nerve to which the particular ganglion sends its postganglionic fibers, but, at operation, the surgeon is unable to obtain this kind of information. It is customary to mark the extent of resection by the application of a dura clip to the proximal and distal ends of the trunk. Roentgenographic visualization later can approximate the level of resection in relation to the vertebrae. Anomalies can lead to unsuccessful denervation of the lower extremities. These include extraganglionic connecting sympathetic nerve trunks, intermediate ganglia, and cross-over fibers connecting the right and left lumbar sympathetic trunks usually at the level of the fourth and fifth lumbar segments, but anatomically sometimes as high as the third and second. Specific complications of lumbar sympathectomy include failure of adequate denervation, brief paralytic ileus, hyperidrosis in parts of the body which remain normally innervated, sexual dysfunction, and post-sympathectomy neuralgia.

Aged↗