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Biomedical subjects

M Sundaram

Publications and source records attributed to M Sundaram.

At least 73 records · Page 4Linked to original sources
PubMed1998

Radiologic case study. Transient migratory osteoporosis of the hip and knee.

Transient migratory osteoporosis is a self-limited disorder characterized by gradual onset of pain over several weeks to months and usually accompanied by characteristic findings on plain radiographs, scintigraphy, and MRI. Transient osteoporosis invariably resolves with conservative management, and therefore it is important to distinguish this uncommon syndrome from other disorders such as osteonecrosis, osteomyelitis, or infiltrative neoplasms, which require aggressive management. An accurate diagnosis of transient bone marrow edema syndrome or transient osteoporosis would lead to appropriate conservative management without biopsy, as in the case presented here.

Adult↗
PubMed1997

Metachronous multiple aneurysmal bone cysts.

We report on a 9-year-old boy with metachronous aneurysmal bone cysts involving the tibia and pubis respectively. The patient has been clinically and radiographically followed for 3 years.

Biopsy↗
PubMed1997

The use of gadolinium in the MR imaging of bone tumors.

Before determining the role of gadolinium in the evaluation of the solitary bone tumor, the practicing radiologist needs to determine which solitary bone lesions merit further evaluation with magnetic resonance imaging and why further imaging is required. A practical approach in applying magnetic resonance imaging to the indeterminate solitary bone lesion is outlined in this article, which serves as a guideline for logical and consistent application of MR imaging for this purpose. Although seemingly widely used, gadolinium appears to add little to the diagnostic sensitivity of specificity of MR with respect to solitary bone lesions. For selective tumors, such as osteosarcoma, gadolinium offers the potential for determining the efficacy of chemotherapy, by evaluating tumor necrosis prior and subsequent to chemotherapy. In select situations, especially sarcomas close to joints, gadolinium may aid and augment other pulse sequences in determining whether tumor resection should be intra- or extra-articular. However, gadolinium has a limited role in the evaluation of the solitary bone tumor, and its use should be the exception rather than the rule.

Antineoplastic Agents↗
PubMed1997

Cloning of a human nucleoside transporter implicated in the cellular uptake of adenosine and chemotherapeutic drugs.

In most mammalian cells nucleoside uptake occurs primarily via broad-specificity, es (e, equilibrative; 5, sensitive to NBMPR inhibition) transporters that are potently inhibited by nitrobenzylthioinosine (NBMPR). These transporters are essential for nucleotide synthesis by salvage pathways in hemopoietic and other cells that lack de novo pathways and are the route of cellular uptake for many cytotoxic nucleosides used in cancer and viral chemotherapy. They play an important role in adenosine-mediated regulation of many physiological processes, including neurotransmission and platelet aggregation, and are a target for coronary vasodilator drugs. We have previously reported the purification of the prototypic es transporter from human erythrocytes and have shown that this glycoprotein of apparent M, 55,000 is immunologically related to nucleoside transporters from several other species and tissues, including human placenta. Here we report the isolation of a human placental cDNA encoding a 456-residue glycoprotein with functional characteristics typical of an es-type transporter. It is predicted to possess 11 membrane-spanning regions and is homologous to several proteins of unknown function in yeast, nematodes, plants and mammals. Because of its central role in the uptake both of adenosine and of chemotherapeutic nucleosides, study of this protein should not only provide insights into the physiological roles of nucleoside transport but also open the way to improved therapies.

Adenosine↗
PubMed1997

Ras is required for a limited number of cell fates and not for general proliferation in Caenorhabditis elegans.

Experiments with mammalian tissue culture cells have implicated the small GTPase Ras in the control of cellular proliferation. Evidence is presented here that this is not the case for a living animal, the nematode Caenorhabditis elegans: proliferation late in embryogenesis and throughout the four larval stages is not noticeably affected in animals lacking Ras in various parts of their cell lineages. Instead, genetic mosaic analysis of the let-60 gene suggests that Ras is required only, at least later in development (a maternal effect cannot be excluded), for establishment of a few temporally and spatially distinct cell fates. Only one of these, the duct cell fate, appears to be essential for viability.

Animals↗
PubMed1997

Clinics in diagnostic imaging (21). Intraosseous lipoma of the calcaneum.

A 50-year-old woman presented with plantar foot pain. Radiographs and computed tomography demonstrated an intraosseous lipoma of the calcaneum. Curettage and packing were performed. The imaging features, including the magnetic resonance appearances, of intraosseous lipomas are described.

Bone Neoplasms↗
PubMed1996

Warfarin-induced spondyloarthropathy with pseudotumor-like appearance. A case report.

STUDY DESIGN: This case report illustrates an unusual complication of chronic warfarin administration. OBJECTIVES: The presurgical determination that the destructive process at L1-L2 was not infection or neoplasm involved the recognition that there was instability at this level resulting from chronic stress fractures. SUMMARY OF BACKGROUND DATA: Periosteal or osseous hemorrhagic masses (pseudotumors) have been well described in patients with hemophilia. To the authors' knowledge, this is the first reported case of this well-known phenomenon occurring in the axial skeleton as a consequence of warfarin administration. METHODS: Serial radiographic studies of the lumbar spine were available showing a progressive destructive lesion at L1-L2 and coinciding with the initiation of warfarin anticoagulation after aortic valve replacement. RESULTS: The destructive mass was demonstrated surgically to represent a large partially solidified chronic hematoma. CONCLUSIONS: Patients with stress fractures of the posterior arch and subsequent instability may be subject to development of such a spondyloarthropathy. Recognition of this unusual potential complication of warfarin therapy would prevent an incorrect diagnosis of tumor or infection. Early recognition of its occurrence could lead to early spinal stabilization.

Aged↗