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Biomedical subjects

J P Latchaw

Publications and source records attributed to J P Latchaw.

11 recordsLinked to original sources
PubMed1985

Medulloblastoma. Period of risk reviewed.

Collins postulated that patients with Wilms' tumor surviving for a period equal to their age at diagnosis plus 9 months were no longer at risk for a recurrence. Although this no longer holds for Wilms' tumor, it has been applied to patients with medulloblastoma. Case histories of patients who survived a period of risk designated by Collins' rule and later developed a histologically confirmed recurrent medulloblastoma are discussed. Reported cases violating Collins' rule constitute less than 2% of all medulloblastomas. The continued use of Collins' rule is advocated. Patients who have survived this period of risk, are neurologically stable, and have a negative computerized tomography (CT) head scan are exceedingly unlikely to develop a recurrent medulloblastoma.

Age Factors↗
PubMed1985

Treatment of acute focal cerebral ischemia and recirculation with d-propranolol.

The purpose of the investigation was to evaluate the effects of d-propranolol upon temporary cerebral ischemia followed by a period of reperfusion, that is, a situation analogous to major cerebral artery embolization. Twenty adult cats, lightly anesthesized with nitrous oxide, underwent 4 hours of right middle cerebral artery (MCA) occlusion and 2 hours of recirculation. Ten cats were untreated and 10 cats received d-propranolol, the weak beta-blocking isomer of racemic (d,l) propranolol. The d-propranolol was infused directly into the right carotid artery at doses of 2 mg/kg, given as a bolus immediately before MCA occlusion, and 0.33 mg/kg/hour, given continuously for 6 hours beginning immediately after MCA occlusion. Systemic arterial blood pressure was similar in both groups, but heart rate was transiently reduced in the treated group immediately after the bolus injection of d-propranolol and MCA occlusion. Regional cerebral blood flow (rCBF), measured by the xenon-133 clearance technique, was not significantly different in the ischemic, right hemisphere. Electroencephalographic (EEG) activity changes in the ischemic, right hemisphere were similar in both groups, but there was significant deterioration of EEG activity in the left, nonischemic hemisphere of untreated cats after MCA reopening. Swelling of the ischemic, right hemispheres was similar in both groups and more severe than in previous studies wherein there was no recirculation phase. Carbon perfusion and blood-brain barrier changes were also similar. The results of the study failed to show a protective effect despite theoretical beneficial actions of d-propranolol. Also, the study demonstrated that d-propranolol does not have a detrimental effect upon rCBF in acute focal cerebral ischemia.

Animals↗
PubMed1984

Thromboxane synthetase inhibition in acute focal cerebral ischemia in cats.

The purpose of this investigation was to study the effects of a selective thromboxane A2 (TXA2) synthetase inhibitor (TSI) upon the evolution of cerebral infarction in the cat. Adult cats, lightly anesthetized with nitrous oxide, underwent right middle cerebral artery (MCA) occlusion for 4 hours followed by a 2-hour period of reperfusion before sacrifice. Ten cats received 3 mg/kg TSI intravenously immediately before, and 10 cats received 3 mg/kg TSI intravenously immediately after MCA occlusion. Ten cats were used as controls receiving no treatment. The bleeding time was determined at baseline and at the end of each experiment. Electroencephalographic (EEG) recordings were obtained before and after MCA clipping and MCA release, and at hourly intervals thereafter. Regional cerebral blood flow (rCBF) was measured using the xenon-133 (133Xe) clearance technique before and after MCA occlusion, after MCA reopening, and before terminating each experiment. Thirty minutes before each cat was sacrificed, Evans blue dye and sodium fluorescein were given intravenously. The animals were then perfused with colloidal carbon and the brains removed and evaluated for midline shift. Evans blue dye and sodium fluorescein extravasation, carbon staining, and infarct size. The bleeding time, arterial blood pressure, rCBF changes, brain swelling, and vital dye extravasation were not statistically different between the three treatment groups. The EEG changes, carbon staining, and infarct size differences between the three groups also failed to reach statistical significance, but there was a suggestion that these parameters were adversely affected in the cats pretreated with TSI. Ten additional cats undergoing MCA occlusion and reperfusion were used for pharmacological studies. Five of them received 3 mg/kg TSI intravenously immediately after MCA occlusion, and serial drug and thromboxane B2 (TXB2) levels (a stable metabolite of TXA2) were determined. Another five cats were not treated and serial TXB2 levels were obtained. Production of TXA2 was inhibited by 95% in cats receiving TSI. In conclusion, thromboxane synthetase inhibition failed to modify favorably the evolution of cerebral infarction. When TSI was given before MCA occlusion, cerebral infarction tended to be more extensive.

Animals↗
PubMed1983

Trigeminal neuralgia treated by radiofrequency coagulation.

Ninety-six patients underwent percutaneous radiofrequency coagulation (RC) of the Gasserian ganglion for relief of trigeminal neuralgia between 1973 and 1978. Fifty-two percent of patients who were followed for 5 years were free of recurrence after a single RC procedure. Factors predicting clinical results were sought from initial historical and demographic data. Age, sex, duration of illness, and previous response to medication were unrelated to outcome. Patients previously treated by open surgery appeared to receive less benefit from subsequent RC. The RC procedure seemed more effective in the treatment of patients with classical tic douloureux than in those with atypical features. The degree of sensory loss created by RC was associated with the clinical outcome. Patients acquiring dense sensory deficits demonstrated a reduced risk of recurrence (p = 0.006): 25% of patients with dense sensory loss and 55% of those with a partial deficit developed a recurrence by 5 years, whereas all patients without initial sensory loss suffered a recurrence by 5 years.

Adult↗
PubMed1982

Encouraging surgical results in walking patients with epidural metastases.

The management of epidural metastases is in a state of controversy between combined surgical and radiation treatment and treatment by radiation alone. Review of the literature shows that one group, patients who are ambulatory before treatment, have been studied rarely. We analyzed our last 15 years of experience at the Cleveland Clinic and found 39 patients who were ambulatory preoperatively; 84% of these walked during the short term follow-up and 93% of the 1-year survivors walked. These data suggest that surgery has an important role in the management of ambulatory patients.

Epidural Space↗
PubMed1981

Treatment of acute focal cerebral ischemia with concentrated albumin.

The object of the investigation was to study the effects of concentrated albumin upon the evolution of cerebral infarction. Twenty adult cats lightly anesthetized with ketamine hydrochloride underwent right middle cerebral artery (MCA) occlusion for 6 hours. Ten cats were not treated and 10 cats received concentrated (i.e., 25 g/100 ml) human serum albumin (5 ml/kg i.v.) at the time of MCA occlusion. The blood volume increased 30 to 40% in the cats receiving concentrated albumin. The hematocrit fell for 32 +/- 5% (SD) before occlusion to 23 +/- 6% at 2.5 hours after occlusion in treated cats, whereas the hematocrit in untreated cats remained stable at 35 +/- 5. Regional cerebral blood flow (rCBF) changes in the right sylvian region were similar in the untreated and treated groups. The mean rCBF before occlusion was 42 +/- 11 ml/100 g/minute in the untreated cats and 44 +/- 8 ml/100 g/minute in the treated cats. Untreated and treated cats had similar reductions of rCBF in the right sylvian region to less than or equal to 18 ml/100 g/minute at some point after occlusion. An index of erythrocyte flow and microcirculatory resistance was determined by measuring the transit of 99Tc-labeled erythrocytes in the right sylvian region. The erythrocyte transit time before occlusion was 10 +/- 2 seconds in the untreated group and 9 +/- 1 seconds in the treated group. After 6 hours, the erythrocyte transit was 19 +/- 3 seconds in the untreated group and 15 +/- 3 seconds in the treated group (p less than or equal to 0.1), suggesting that less microcirculatory impairment occurred in some treated cats. Electroencephalographic changes during the initial 3 hours of occlusion were less severe in the treated cats than in the untreated cats, suggesting that the collateral flow in the border zone of the MCA territory initially may have been improved by treatment. Impairment of carbon perfusion, ischemic edema, and neuronal alterations after 6 hours of occlusion were the same in both groups. Increased permeability of the blood-brain barrier to Evans blue dye, however, was more marked in the treated group. The findings of the study indicate that concentrated albumin does not substantially modify the evolution of cerebral infarction.

Animals↗
PubMedDate not supplied

Treatment of acute focal cerebral ischemia with propranolol.

Propranolol has been found to have a protective effect in experimental myocardial ischemia. Protection of ischemic kidneys was subsequently demonstrated following treatment with propranolol and its weaker beta blocking isomer, d-propranolol. The objective of the present investigation was to study the effects of propranolol (i.e., racemic d,1 mixture) and d-propranolol upon regional cerebral blood flow (rCBF) and early ischemic changes following experimental middle cerebral artery (MCA) occlusion. Thirty adult cats, lightly anesthetized with ketamine hydrochloride, underwent 3 hours or right MCA occlusion. Ten cats were untreated. Ten cats were given a continuous infusion of propranolol (1 mg/kg/hr) for 4 hours beginning 1 hour before MCA occlusion and a 4 mg/kg bolus immediately before occlusion. Ten cats were given a continuous infusion of d-propranolol (0.5 mg/kg/hr) for 4 hours beginning 1 hour before MCA occlusion and a 2 mg/kg bolus immediately before occlusion. The therapeutic agents were injected directly into the right carotid artery. The rCBF in the right Sylvian region was not significantly different in the 3 groups. EEG changes also were similar. Carbon filling defects were found to be smallest in the d-propranolol-treated group. Light microscopic studies demonstrated a reduction in infarct size in the propranolol and d-propranolol groups. The findings of the investigation indicated that propranolol and d-propranolol do not have a deleterious effect on rCBF after MCA occlusion and suggested that these agents have a protective effect upon ischemic cerebral tissue.

Animals↗
PubMedDate not supplied

Treatment of acute focal cerebral ischemia with propranolol.

Propranolol's potential as a protective agent against tissue injury has been noted in experimental myocardial, renal and early acute focal cerebral ischemia. The purpose of the present investigation was to study further the effects of racemic (d,l) propranolol on blood-brain barrier permeability, morphological changes, cortical electrical activity, and regional cerebral blood flow (rCBF) in experimental focal cerebral ischemia. Thirty adult cats, anesthetized with nitrous oxide, underwent 6 hours of right middle cerebral artery (MCA) occlusion. Fifteen cats were untreated. Fifteen cats were given a continuous infusion of racemic propranolol (1 mg/kg/hr) for 7 hours beginning 1 hour before MCA occlusion and a 4 mg/kg bolus immediately before occlusion, both directly into the right carotid artery. Right Sylvian rCBF did not significantly differ in the treated and untreated groups. Carbon filling defects and vital dye (i.e., Evans blue and fluorescein) extravasation were less severe in the propranolol treated animals. Light microscopic findings demonstrated no difference in infarct size between the two groups. The findings suggest that at doses given, racemic propranolol does not exert a protective effect upon cerebral tissue subjected to 6 hours of incomplete ischemia.

Animals↗