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Biomedical subjects

D Gale

Publications and source records attributed to D Gale.

18 recordsLinked to original sources

Trigeminal neuralgia and multiple sclerosis. A complex diagnosis.

Trigeminal neuralgia is a well-recognized complication in patients with multiple sclerosis. A case report is presented that describes multiple sclerosis in a middle-aged man with otherwise classical unilateral trigeminal neuralgia who demonstrated a variable response to pharmacologic and surgical intervention. The case highlights the difficulties of diagnosis when trigeminal neuralgia occurs concurrently with multiple sclerosis.

Adult

Exacerbation of experimental colitis by nonsteroidal anti-inflammatory drugs is not related to elevated leukotriene B4 synthesis.

The ability of nonsteroidal anti-inflammatory drugs to exacerbate experimental colitis, and the possible contributions of the "shunting" of arachidonate via the 5-lipoxygenase pathway, were investigated using a rat model in which colitis was induced by intracolonic administration of trinitrobenzene sulfonic acid in a vehicle of 50% ethanol. Twice daily treatment with indomethacin (0.1-1 mg/kg SC) during the first week after trinitrobenzene sulfonic acid/ethanol administration resulted in dose-dependent increases in the severity of colitis and in the incidence of mortality. Mortality was not observed in vehicle-treated colitic rats or in normal rats treated with indomethacin. Similar exacerbation of colitis was observed in rats treated with naproxen (5 mg/kg). Whereas treatment with a 5-lipoxygenase inhibitor, PF-5901 (100 mg/kg PO), resulted in a significant reduction of the severity of colitis, concomitant administration of PF-5901 and indomethacin (0.5 mg/kg SC) did not inhibit the exacerbative effects of the indomethacin in this model. In separate studies, administration of indomethacin was found to significantly increase colonic myeloperoxidase activity (a measure of tissue granulocyte numbers) and suppress colonic prostaglandin E2 synthesis, while not significantly affecting colonic leukotriene B4 synthesis. The effect on myeloperoxidase activity was seen during the period 21-24 hours after trinitrobenzene sulfonic acid ethanol administration, but not during the period 45-48 hours after induction of colitis. In in vitro studies using samples of inflamed colon and in vivo studies in which colonic eicosanoid production was measured by colonic dialysis, inhibition of prostaglandin E2 synthesis was not accompanied by significant changes in leukotriene B4 synthesis. These results suggest that inhibitors of colonic prostaglandin synthesis can markedly exacerbate colitis, and that this effect is unrelated to alterations in colonic leukotriene B4 synthesis. Endogenous prostaglandins may exert anti-inflammatory effects during the acute stages of colitis.

Animals

Posterior cerebral artery stenosis.

We analyzed the clinical features of symptomatic posterior cerebral artery (PCA) stenosis in 6 patients selected from 15 patients with angiographically documented PCA atherostenosis occurring during a 7-year period. Transient ischemic attacks (TIAs) were the major presentation in 5 patients. A homonymous visual field defect was present in 2 patients. TIA symptoms were predominantly visual or sensory, or both. The most common visual symptom was difficulty seeing to one side. One patient saw flashing lights. Sensory spells were always paresthetic, usually involving the arm and hand and occasionally the face and leg. Three patients had visual and sensory spells together. Two patients with a visual field defect had calcarine infarcts found by computed tomography. All patients were treated with warfarin. During follow-up (4 months to 4 years), no patient had a new stroke in the PCA territory, and only one continued to have TIAs. PCA atherostenosis is rarer then PCA embolic occlusion. In contrast to those with PCA embolism, our patients with PCA atherostenosis had more TIAs and fewer infarcts. The clinical features of PCA stenosis--preponderance of visual and sensory TIAs--distinguish this vascular lesion from stenosis of the middle cerebral artery.

Aged

Isotope-dilution assay for urinary methylmalonic acid in the diagnosis of vitamin B12 deficiency. A prospective clinical evaluation.

Vitamin B12 deficiency is a frequently considered diagnosis for which there is no single, commonly available and accurate test. A urinary methylmalonic acid assay using gas chromatography-mass spectrometry has been proposed as the preferred test. We reviewed vitamin B12 assays on 1599 consecutive patients and prospectively studied all patients with low serum B12 levels (n = 75) and a random sample of patients with normal levels (n = 68). Of 96 evaluable patients, 7 had clinical deficiency. All 7 deficient patients had urinary methylmalonic acid levels greater than 5 micrograms/mg creatine (sensitivity, 100%; confidence interval, 65% to 100%). Of the 89 patients who were not clinically deficient, 88 had urinary methylmalonic acid levels less than or equal to 5 micrograms/mg creatinine (specificity, 99%). The overall test accuracy in this population was 99%. If the high sensitivity and specificity of the gas chromatography-mass spectrometry assay for urinary methylmalonic acid is supported by other clinical studies, the methylmalonic acid assay may become the reference standard for the diagnosis of vitamin B12 deficiency.

Aged

Oxygen consumption of chronically stimulated skeletal muscle.

The latissimus dorsi muscles of six dogs were made fatigue resistant by chronic electrical conditioning. Once the muscles were conditioned, oxygen consumption was measured during periods of exercise. The ratio of the tension developed to oxygen consumed during moderate stimulation (300 msec on) for the control and the electrically conditioned muscles was 16.3 +/- 3.5 and 36.5 +/- 6.7 kg-sec/ml oxygen, respectively. During intense stimulation (800 msec on) the ratio was 12.6 +/- 2.1 and 54.2 +/- 8.9 kg-sec/ml oxygen, respectively. Thus the conditioned muscle was able to develop and maintain tension with a considerably reduced oxygen expenditure. The increased efficiency of the conditioned muscle helps to explain its increased resistance to fatigue and the ability of pumping chambers constructed from electrically preconditioned skeletal muscle to perform sustained cardiac type work.

Animals

Visual field defects in medico-legal cases.

A retrospective survey of the incidence of spiral visual fields, both bilateral and unilateral, in a group of 1,143 cases seen for the purpose of giving a medico-legal opinion is described.

Accidents