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Biomedical subjects

S Khouri

Publications and source records attributed to S Khouri.

14 recordsLinked to original sources
PubMed2005

[Giant extradural epidermoid cyst of the posterior fossa].

We report an unusual case of giant extradural epidermoid cyst of the posterior fossa in a 73-year-old man. The patient presented headache and gait disturbance for 3-4 months, cerebellar ataxia, left cerebellar dysmetria, and perturbed balance. The CT-scan showed a huge posterior fossa extradural lesion with a small area of peripheral contrast enhancement. Outcome was good after total resection of the lesion via a suboccipital approach. Pathology reported an epidermoid cyst. Extradural epidermoid cyst is a rare benign tumor of the skull which sometimes can reach considerable size. It is a slow growing lesion and may cause mild neurological deficits. The goal of surgical treatment is total resection of the tumor with its capsule. The long-term prognosis is excellent after successful resection.

Aged↗
PubMed2001

Sarcoidosis: the value of exercise testing.

STUDY OBJECTIVES: To evaluate exercise testing for the assessment of the extent of pulmonary disease in patients with sarcoidosis. DESIGN: Retrospective analysis of consecutive patients with sarcoidosis referred to the Pulmonary Physiology Laboratory between 1992 and 1997, who completed at least 6 min of progressive bicycle exercise. Resting and exercise pulmonary function measurements were compared to radiographic stage of disease. SETTING: Pulmonary Physiology Laboratory at Washington, DC, Veterans Affairs Medical Center. PATIENTS: Forty-eight outpatient veterans with biopsy specimen-proven sarcoidosis. RESULTS: Across all radiographic stages of sarcoidosis, total lung capacity, resting diffusing capacity, and exercise gas exchange measurements had a significant variance with radiographic stage. Across the early radiographic stage disease (stages 0 to 2), the change in alveolar-arterial oxygen pressure gradient between rest and exercise, normalized for oxygen uptake, was the most significant measurement in its variation with radiographic stage. CONCLUSIONS: Changes in gas exchange with exercise may be the most sensitive physiologic measurements to assess the extent of disease in early radiographic stages of sarcoidosis.

Adult↗
PubMed2000

Non-invasive grading of oligodendrogliomas: correlation between in vivo metabolic pattern and histopathology.

Several studies have shown that the prognosis of oligodendrogliomas is dependent on their histological grade. In order to identify a non-invasive method for the primary diagnosis and follow-up of these tumours, we investigated the relationship between their in vivo metabolism, assessed by positron emission tomography (PET), and their histological grade assessed at the same time. Forty-seven patients with histologically confirmed oligodendrogliomas were investigated. Conventional neuroradiological assessment by computed tomography and magnetic resonance imaging (MRI) was performed in all the patients. All the histology slices were reviewed by the same pathologist after referral from various pathology laboratories. The PET investigation included a carbon-1 methionine (11C-MET) uptake study and, in the majority of cases, a fluorine-18 fluorodeoxyglucose (18F-FDG) uptake study, in order to investigate at the same time both amino acid metabolism and glycolysis. The sampled tumour region of interest (ROI) was defined from the T1-weighted 3D MR scan matched with the PET scan. Tracer concentration in each voxel of the tumour ROI was divided by the mean concentration in an ROI of the same size located in the healthy brain tissue. For each tumour and each tracer, we characterized the metabolic pattern on the basis of the mean and the maximum tumour to healthy tissue concentration ratio, and also the standard deviation and range of the ratios, which indicate the degree of metabolic heterogeneity of the tumour. The histological criteria for differentiating between high- and low-grade tumours were those of the WHO and, partially, of the Sainte-Anne-Daumas-Duport classification. Highly significant differences between high- and low-grade oligodendrogliomas (Mann-Whitney test: P<0.0001) were observed for all the assessed parameters of 11C-MET uptake. On the other hand, the pattern of 18F-FDG uptake showed only moderate differences between the two tumour groups.

Adult↗
PubMed2000

Lactic acidosis secondary to nucleoside analogue antiretroviral therapy.

A 53-year-old woman with newly diagnosed HIV infection was treated with the nucleoside analogue antiretroviral agents lamivudine and stavudine and the protease inhibitor indinavir. An illness characterized by severe lethargy, persistent nausea and vomiting, lactic acidosis, hyperglycemia, and microvesicular hepatic steatosis developed. Her symptoms improved gradually after withdrawal of the antiretroviral agents. The illness can be explained by mitochondrial dysfunction caused by inhibition of mitochondrial DNA (mtDNA) polymerase by the nucleoside analogues. The patient was successfully treated with nonnucleoside reverse transcriptase inhibitors, which lack affinity for mtDNA polymerase.

Acidosis, Lactic↗
PubMed1999

Creatine kinase as a biochemical marker in diagnosis of placenta increta and percreta.

We describe 1 case of placenta increta and 1 of placenta percreta, both associated with elevated maternal serum creatine kinase concentration. In patients with placenta previa and ultrasonographic findings of an abnormally adherent placenta, an unexplained elevation in maternal serum creatine kinase level should alert the clinician to the possibility of placenta increta or placenta percreta, with an attendant increase in maternal morbidity.

Adult↗
PubMed1997

Evaluation of patterns of perfusion and metabolism in dobutamine-responsive myocardium.

OBJECTIVES: We investigated the patterns of perfusion and metabolism in dysfunctional myocardium whose contractility improved with dobutamine. BACKGROUND: Clinical studies have suggested that dobutamine echocardiography can identify hibernating myocardium, but laboratory studies suggest that reduced perfusion limits the response to dobutamine. METHODS: Twenty-five patients with coronary disease and ventricular dysfunction underwent low (5 and 10 micrograms/kg body weight per min) and high dose (maximum of 50 micrograms/kg per min) dobutamine echocardiography and positron emission tomography (PET) using nitrogen-13 (N-13) ammonia and fluorine-18 fluorodeoxyglucose (FDG) for imaging of perfusion and metabolism. Wall motion and tracer uptake were scored in 16 left ventricular segments. RESULTS: Perfusion and metabolism were normal in 56.4%, mildly reduced in 29.1% and mismatched (reduced perfusion, preserved FDG uptake) in 14.5% of dysfunctional segments viable on PET. Wall motion improved with dobutamine in 89 dysfunctional segments (62 at low dose, 27 only at peak dose), and 86 of these (97%) were viable on PET. Improvement in wall motion with dobutamine was more common in segments with normal perfusion and metabolism (56.5%) than in those with mildly reduced tracer uptake (28.5%, p < 0.001) and those with mismatch (32%, p = 0.03). All the segments with a biphasic response were supplied by vessels with > or = 70% stenosis, and 88% had normal perfusion and metabolism. CONCLUSIONS: The majority of viable segments with rest dysfunction had normal perfusion and metabolism, suggesting that myocardial stunning was common. Improvement of wall motion at low and high doses of dobutamine was highly correlated with myocardial viability on PET and was more common in myocardium with normal perfusion. A biphasic response to dobutamine identified segments with normal perfusion and metabolism supplied by severely diseased vessels.

Ammonia↗
PubMed1996

Exner's Depression Index and the Harris-Lingoes MMPI-2 subscales for depression.

This study examined the relationship between scores on the Harris-Lingoes MMPI-2 subscales for Depression and the categories of Exner's Rorschach Depression Index (DEPI) for 53 clients of a counselling agency. Scores on the subscale Mental Dullness related to the Depression Index as a whole and to the category Blends < 4. The subscale Subjective Depression also related to the category Blends < 4.

Adaptation, Psychological↗
PubMed1991

Influence of dietary fat composition on development of insulin resistance in rats. Relationship to muscle triglyceride and omega-3 fatty acids in muscle phospholipid.

High levels of some but not all dietary fats lead to insulin resistance in rats. The aim of this study was to investigate the important determinants underlying this observation. Insulin action was assessed with the euglycemic clamp. Diets high in saturated, monounsaturated (omega-9), or polyunsaturated (omega-6) fatty acids led to severe insulin resistance; glucose infusion rates [GIR] to maintain euglycemia at approximately 1000 pM insulin were 6.2 +/- 0.9, 8.9 +/- 0.9, and 9.7 +/- 0.4 mg.kg-1. min-1, respectively, versus 16.1 +/- 1.0 mg.kg-1.min-1 in chow-fed controls. Substituting 11% of fatty acids in the polyunsaturated fat diet with long-chain omega-3 fatty acids from fish oils normalized insulin action (GIR 15.0 +/- 1.3 mg.kg-1.min-1). Similar replacement with short-chain omega-3 (alpha-linolenic acid, 18:3 omega 3) was ineffective in the polyunsaturated diet (GIR 9.9 +/- 0.5 mg.kg-1.min-1) but completely prevented the insulin resistance induced by a saturated-fat diet (GIR 16.0 +/- 1.5 mg.kg-1.min-1) and did so in both the liver and peripheral tissues. Insulin sensitivity in skeletal muscle was inversely correlated with mean muscle triglyceride accumulation (r = 0.95 and 0.86 for soleus and red quadriceps, respectively; both P less than 0.01). Furthermore, percentage of long-chain omega-3 fatty acid in phospholipid measured in red quadriceps correlated highly with insulin action in that muscle (r = 0.97). We conclude that 1) the particular fatty acids and the lipid environment in which they are presented in high-fat diets determine insulin sensitivity in rats; 2) impaired insulin action in skeletal muscle relates to triglyceride accumulation, suggesting intracellular glucose-fatty acid cycle involvement; and 3) long-chain omega-3 fatty acids in phospholipid of skeletal muscle may be important for efficient insulin action.

Animals↗
PubMed1989

Fructose-induced in vivo insulin resistance and elevated plasma triglyceride levels in rats.

Insulin action was assessed by using the hyperinsulinemic (approximately 800 pmol/L) euglycemic clamp in rats fed equal amounts of glucose or fructose (35% of calories) for 4 wk. The glucose infusion rate required to maintain euglycemia was decreased in fructose-fed animals (14.6 +/- 1.4 vs 21.8 +/- 1.1 for glucose-fed rats, p less than 0.001) with this whole-body effect contributed to equally by an impairment in hepatic insulin action and a reduction in peripheral glucose disposal in a range of tissues. There was no difference in basal glucose turnover, energy expenditure, or postprandial blood glucose and insulin responses to the diets. In the fructose-fed rats there was an increase in fasting triglyceride levels by 2 wk. Euglycemic clamp glucose disposal correlated positively and clamp hepatic glucose output correlated negatively with fasting triglyceride levels. In summary, fructose but not glucose feeding led to impaired insulin action in both the liver and peripheral tissues, effects that may depend on antecedent circulating triglyceride levels.

Animals↗
PubMed1989

[Intracerebellar schwannoma. Apropos of a case. Review of the literature].

Intracranial schwannoma represents 8% of all primary brain tumors. It usually develops from the Schwann cells of a cranial nerve. Hemispheric intraparenchymal localisations are quite rare; 15 cases have been reported (3, 5, 12, 10, 14, 15, 18, 19, 23, 26, 28, 29) including one intraventricular localization (8). Intracerebellar localization is even by more exceptional. In 1977, one case was reported by Komminoth (16). Since then only one other case has been published in 1987 by Sarkar (25). In this paper, we report a third case.

Cerebellar Neoplasms↗
PubMedDate not supplied

[Hepatotoxic substances in Brazilian rum].

The purpose of this study was to investigate whether Brazilian "pingas" (liquor distilled from sugar cane) contain toxic agents other than ethanol at levels which might risk consumers health, especially regarding liver damage. We have studied 8 different "pingas" in which the levels of iron, copper and zinc were measured through an atomic absorption method, and the levels of ethanol, acetaldehyde, n-propanol, ethyl acetate, isobutane, and isoamylic alcohol were measured through gas chromatography and mass spectrometry. Iron levels were higher than those allowed in two liquors, samples 1 and 8 (respectively 0.57 mg/L and 0.38 mg/L). Such levels may be considered deleterious to health if these liquors are consumed in great amounts and during large periods, especially if a synergistic interaction between alcohol and iron exists, as accepted by some authors. Our findings warrant that further studies be performed.

Alcoholic Beverages↗