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Biomedical subjects

S Tilak

Publications and source records attributed to S Tilak.

9 recordsLinked to original sources

Intracranial mass lesions: sequential thallium and gallium scintigraphy in patients with AIDS.

PURPOSE: To determine the efficacy of sequential thallium and gallium scintigraphy to differentiate intracranial neoplasms (lymphoma and glioma) from other nonmalignant intracranial mass lesions among patients with acquired immunodeficiency syndrome (AIDS). MATERIALS AND METHODS: The authors reviewed the cases of 40 patients with human immunodeficiency virus (HIV) who underwent thallium and gallium scanning to evaluate intracranial mass lesions from October 1991 through November 1997. There was a definitive final diagnosis of the nature of the mass lesions in 21 of these cases. In these 21 cases, the scintigraphic patterns were reviewed and were compared with the final diagnosis. RESULTS: On the basis of results at thallium and gallium scanning, the patients were divided into three groups. Group A included 13 patients (11 with brain tumors [lymphomas and gliomas] and two with progressive multifocal leukoencephalopathy [PML]) with thallium-positive, gallium-positive scans. Group B included five patients with intracranial infections (tuberculosis, Cryptococcus, bacteria) with thallium-negative, gallium-positive scans. Group C included three patients (one with PML and two with infarcts) with thallium-negative, gallium-negative scans. All patients with lymphomas were in group A. The sensitivity and specificity of the thallium-positive, gallium-positive pattern for intracranial malignancy were 100% and 80%, respectively. CONCLUSION: Sequential thallium and gallium scanning helped differentiate tumors from nonmalignant intracranial mass lesions and may help differentiate infections from PML or infarcts.

Acquired Immunodeficiency Syndrome↗

Evidence of cortical metabolic dysfunction in early Huntington's disease by single-photon-emission computed tomography.

We compared perfusion of prefrontal, motor, and sensory cortices and basal ganglia in 29 Huntington's disease (HD) patients and nine controls. We found a significant reduction in perfusion in patients with HD of short (< 6 years, n = 10), medium (6-10 years, n = 8), and long duration (> 10 years, n = 11) compared with controls. Among short-duration patients, we observed decreases in cortical perfusion before evidence of atrophy on magnetic resonance imaging, suggesting that decreases in neuronal activity, as reflected by perfusion levels, precede gross structural changes. As expected, decreased perfusion was marked in basal ganglia. The extent of cortical perfusion correlated with clinical assessments of functional capabilities as well as with the duration of disease. Prefrontal perfusion correlated with cognitive measures, and motor cortical perfusion correlated with physical disability and activities of daily living scores. We found no significant clinical correlations with sensory cortical perfusion. Single-photon-emission computed tomography may be a sensitive method for assessing disease progression in clinical trials and pharmacologic intervention.

Adult↗

Normal anatomy of the skull base.

CT and MR imaging increasingly are being used for the evaluation of the skull base. New innovative techniques have revolutionized radiologic understanding of normal skull base anatomy. Thus, normal anatomic relationships with radiographic correlation are vital for accurate pathologic assessment.

Humans↗

Action of delta 9-tetrahydrocannabinol on the pool of acid soluble nucleotides.

The effects of delta 9-tetrahydrocannabinol (THC) treatment on acid soluble pools of uridine nucleoside and nucleotides were investigated in Tetrahymena pyriformis and in isolated mouse lymphocytes and spermatogenic cells. In THC treated Tetrahymena and mouse lymphocytes the uptake of labelled precursor into acid soluble pools of uridine nucleoside and nucleotides fluctuated, whereas in pachytene spermatocytes and round spermatid cells the labelled pool was reduced. The reduction in the labelled pool measured in mouse spermatogenic cells was attributed primarily to a reduction in radioactively labelled uridine nucleoside. Treatment of Tetrahymena in high concentrations of THC (960 and 3,200 microM) resulted in an increase of labelled uridine nucleoside and a reduction in the amount of labelled uridine nucleotides. Expansion of the acid soluble pool with radioactive uridine resulted in small differences in labelled nucleoside and nucleotides in control and THC treated Tetrahymena and mouse lymphocytes. The results are discussed in terms of the effects of THC on macromolecular synthesis in various cellular systems.

Animals↗

Temporal arteritis-like presentation of carotid atherosclerosis.

A 68 year-old woman presented with a two-week history of amaurosis fugax, ipsilateral fronto-temporal headache and jaw claudication suggesting carotid giant cell arteritis. However, this syndrome proved to be due to atherosclerosis causing complete occlusion of the external carotid artery at its origin and narrowing of the internal carotid artery. Combined external and internal carotid endarterectomy relieved the symptoms. The symptom complex of temporal arteritis may be rarely mimicked by carotid atherosclerotic occlusive disease.

Aged↗