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Biomedical subjects

N Pandit

Publications and source records attributed to N Pandit.

At least 19 recordsLinked to original sources

The 'mouse face' appearance of the vertebrae in Paget's disease.

Paget's disease is occasionally found as an incidental finding on bone scans performed for the evaluation of metastatic disease, which causes a diagnostic and a subsequent therapeutic dilemma. We have previously described the "Mouse Face" appearance of vertebrae on bone scans (increased uptake in the vertebral body, posterior elements, and the spinous process), which was fairly specific for Paget's disease in a small series. This retrospective study was undertaken to determine if this observation holds true in a larger series. Bone scans performed in 2,881 patients were randomly selected, and were reviewed by 2 physicians. Thirty-nine cases with a "Mouse Face" appearance were identified. Diagnosis was established in 30 of the 39 patients by correlative radiographic studies and/or clinical follow-up. Twenty patients were referred for the evaluation of possible metastases, and 7 were found to have metastases at the sites of "Mouse Face". The other 13 had Paget's disease. However, 6 of the 7 patients with metastases had extravertebral findings compatible with multiple metastases, and the remaining patient had a "Mouse Face" lesion only, with a question of metastases. Ten patients were evaluated for Paget's disease or others, and none of them had metastases at the site of the "Mouse Face". The "Mouse Face" appearance is more suggestive of Paget's disease than metastases even in patients with cancer. These patients should be assumed unlikely to have vertebral metastases, unless proven by another correlative radiologic study.

Adult

Brain perfusion imaging during preoperative temporary balloon occlusion of the internal carotid artery.

UNLABELLED: The main objective of this study was to assess whether 99mTc-HMPAO brain SPECT imaging can identify patients at high risk of developing an infarct following permanent carotid occlusion in the course of brain surgery. METHODS: Test balloon occlusion of the internal carotid artery was performed in 44 patients with a variety of head and neck tumors or aneurysms. Technetium-99m-HMPAO was injected intravenously while the balloon was initiated and a SPECT study was obtained 30 min later. Follow-up CT scans were obtained routinely for all patients at 2 wk and 1 mo following surgery, or earlier when necessary. Thirty patients and five normal volunteers had semiquantitative analysis of cerebral perfusion. RESULTS: Twenty-six patients demonstrated ipsilateral perfusion abnormalities during trial occlusion. Eight patients in this group underwent bypass grafting prior to sacrifice of the artery: two resulting in infarcts. Eighteen patients had symmetric cerebral perfusion during occlusion and four of these patients underwent permanent therapeutic carotid occlusion; three patients had subsequent infarcts and the fourth patient had an impending stroke. CONCLUSION: Patients with symmetric cerebral perfusion measured by 99mTc-HMPAO SPECT may still have a high long-term complication rate following carotid sacrifice. The scan findings in these patients were not predictive of the outcome. Patients with asymmetric cerebral perfusion had alternative therapeutic approach to carotid sacrifice and most of them had good surgical outcomes.

Brain

Reversible cerebral perfusion abnormalities associated with cyclosporine therapy in orthotopic liver transplantation.

A 60-yr-old woman experienced several episodes of generalized seizures following 2 wk of immunosuppressive therapy with cyclosporine for orthotopic liver transplantation. CT showed low density in the white matter of the parieto-occipital lobes. A 99mTc-HMPAO brain SPECT showed diminished perfusion in the parieto-occipital cortex bilaterally. Although the cyclosporine was discontinued, the patient's neurologic status initially worsened and then improved over the next several days. Repeat perfusion brain SPECT showed resolution of most of the perfusion abnormalities, while repeat CT showed persistent white matter changes in the parieto-occipital lobes. We report the presence of reversible cortical perfusion abnormalities in conjunction with cyclosporine therapy. The findings suggest that perfusion brain SPECT may be a sensitive monitor of cyclosporine-induced neurotoxicity.

Brain

Variable expression of the Opc outer membrane protein in Neisseria meningitidis is caused by size variation of a promoter containing poly-cytidine.

Opa proteins of Neisseria meningitidis exhibit translational phase variation via addition or deletion of repetitive coding repeat units within the DNA encoding the protein leader sequence. In contrast, Opc phase variation is the result of transcriptional regulation. Transcription starts 13 nucleotides after the -10 region of an unusual promoter sequence containing a variable number of contiguous cytidine residues and lacking a -35 region. Efficient expression of Opc occurred in strains with 12 to 13 cytidine residues, intermediate expression in strains with 11 or 14 residues and no expression with < or = 10 or > or = 15 residues. This unusual regulation may have evolved because the Opc protein enables meningococcal invasion and is immunogenic.

Bacterial Outer Membrane Proteins

Development of 5q- myelodysplasia in a patient with sarcoidosis.

Sarcoidosis has been observed in association with numerous blood dyscrasias including lymphoma, leukemia, and multiple myeloma. This report describes a patient with sarcoidosis and a refractory anemia whose bone marrow karyotype showed deletion of the long arm of chromosome 5, consistent with a myelodysplastic syndrome. Concurrent sarcoidosis and myelodysplasia may relate to the continued availability of cytokines as a consequence of repeated macrophage, T-cell, and B-cell interactions, with evolution to the 5q- abnormality. This association may merit specific attention in the future approach to the diagnostic evaluation in certain patients with sarcoidosis.

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