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M Sundaram

Publications and source records attributed to M Sundaram.

At least 127 records · Page 7Linked to original sources
PubMed1993

Case report 786: Ewing's sarcoma of the left zygoma.

We present a relatively common tumor, Ewing's sarcoma, in an exceptionally rare site, the zygomatic bone, wherein the only symptom was swelling in the cheek despite intracranial extension. Ewing's sarcoma is not an uncommon tumor in the Asian Indian as it is in the African American. It appear to occur as frequently in the subcontinent as it does in Europe and in Americans of European descent.

Adolescent↗
PubMed1993

Elastofibroma dorsi: a radiological diagnosis.

Elastofibroma dorsi is a rarely made radiological diagnosis. The rarity of the condition, lack of a suitable imaging modality, and an inconsistent clinical approach in evaluating indeterminate soft tissue tumors has contributed to this failure. With magnetic resonance imaging now being recognized as the examination of choice for all indeterminate soft tissue tumors, a prebiopsy diagnosis can frequently be made by radiologists familiar with the characteristic periscapular location, predilection for elderly females, and short T2 on magnetic resonance imaging.

Female↗
PubMed1993

Case report 799: Extraskeletal chondrosarcoma (Fig. 3).

In summary, extraskeletal chondrosarcoma is a rare soft tissue tumor. There may or may not be calcification, and in uncalcified tumors the diagnosis may not even be considered by the radiologist. The body of information as to clinical outcome is limited. Both of the patients whose tumors have been illustrated here are alive 2 years following surgery.

Adult↗
PubMed1993

Genetic and phenotypic studies of hypomorphic lin-12 mutants in Caenorhabditis elegans.

The lin-12 gene of Caenorhabditis elegans is thought to encode a receptor for intercellular signals that specify certain cell fates during development. We describe several alleles of lin-12 that reduce but do not eliminate lin-12 activity (hypomorphic alleles). These alleles cause a novel egg-laying defective (Egl) phenotype in hermaphrodites as well as incompletely penetrant cell fate transformations seen with high penetrance in lin-12 null mutants. Characterization of the Egl phenotype revealed additional roles of lin-12 in the development of the egg-laying system that were not apparent from studying lin-12 null mutants: lin-12 activity is required for proper early vulval morphogenesis as well as for some unknown later aspect of egg-laying system development. Reversion of the Egl phenotype caused by one lin-12 hypomorphic allele was used to identify potential interacting genes as described in the accompanying paper.

Alleles↗
PubMed1993

Suppressors of a lin-12 hypomorph define genes that interact with both lin-12 and glp-1 in Caenorhabditis elegans.

The lin-12 gene of Caenorhabditis elegans is thought to encode a receptor which mediates cell-cell interactions required to specify certain cell fates. Reversion of the egg-laying defective phenotype caused by a hypomorphic lin-12 allele identified rare extragenic suppressor mutations in five genes, sel-1, sel-9, sel-10, sel-11 and sel(ar40) (sel = suppressor and/or enhancer of lin-12). Mutations in each of these sel genes suppress defects associated with reduced lin-12 activity, and enhance at least one defect associated with elevated lin-12 activity. None of the sel mutations cause any obvious phenotype in a wild-type background. Gene dosage experiments suggest that sel-1 and sel(ar40) mutations are reduction-of-function mutations, while sel-9 and sel-11 mutations are gain-of-function mutations. sel-1, sel-9, sel-11 and sel(ar40) mutations do not suppress amorphic lin-12 alleles, while sel-10 mutations are able to bypass partially the requirement for lin-12 activity in at least one cell fate decision. sel-1, sel-9, sel-10, sel-11 and sel(ar40) mutations are also able to suppress the maternal-effect lethality caused by a partial loss-of-function allele of glp-1, a gene that is both structurally and functionally related to lin-12. These sel genes may therefore function in both lin-12 and glp-1 mediated cell fate decisions.

Alleles↗
PubMed1993

Synovial sarcoma: MR imaging findings in 34 patients.

OBJECTIVE: MR imaging is considered the procedure of choice for detecting and staging soft-tissue tumors. Its ability to show differences between benign and malignant soft-tissue tumors and its usefulness in suggesting a specific histologic diagnosis remain controversial. We studied the MR features of synovial sarcoma in 34 patients to determine if these tumors have specific MR findings that can be used to suggest the diagnosis. MATERIALS AND METHODS: MR imaging studies of 34 patients with synovial sarcoma were collected from two institutions and studied to determine the following characteristics of the tumor: size, shape, location, signal intensity and homogeneity, margin definition, presence of hemorrhage, and relationships to adjacent structures. These findings were then correlated with pathologic findings. RESULTS: The tumors tended to be deep, large (85% were > or = 5 cm in diameter), and located in the extremities with epicenters close to joints (63% within 7 cm of a joint). The lesions were usually inhomogeneous on T2-weighted images (82%) and clearly delineated from surrounding tissues (91%). Forty-four percent had high signal consistent with hemorrhage on both T1- and T2-weighted images. Fluid-fluid levels, best visualized on T2-weighted images, were present in 18% of patients. Thirty-five percent of the lesions had areas that were hyper-, iso-, and hypointense relative to fat on T2-weighted images, constituting a triple signal intensity. The tumors frequently involved adjacent bone, with 71% invading, eroding, or touching bone. No association of pathologic subtypes with specific imaging findings was noted. CONCLUSION: Our results show a spectrum of MR imaging findings in synovial sarcoma. Nevertheless, the results suggest that synovial sarcoma should be considered when MR images show a relatively well-defined but inhomogeneous hemorrhagic lesion near a joint and in contact with bone. Fluid-fluid levels and areas hyper-, hypo-, and isointense relative to fat (triple signal) on T2-weighted sequences support the diagnosis.

Adolescent↗
PubMed1993

Hippocampal changes in developing postnatal mice following intrauterine exposure to domoic acid.

Domoic acid (0.6 mg/kg) was injected intravenously through the caudal vein in pregnant female mice on the 13th day of gestation and EEG was monitored in the developing progeny during postnatal days 10-30. No clinical seizure activity was observed during this period. However, these mice demonstrated generalized electrocortical inhibition associated with diffuse spike and wave activity in their basal EEG records. Intrauterine domoic acid-exposed (IUD) mice had significantly reduced seizure thresholds to an additional dose of domoic acid, given postnatally. At the light microscopic level, hippocampus of IUD mice exhibited age related developmental neurotoxicity. No cellular damage was observed on postnatal day 1. On day 14, severe neuronal damage was observed in the hippocampal CA3 and dentate gyrus regions. On day 30, in addition to CA3 and dentate gyrus, CA4 was also involved. Brain regional GABA levels were significantly reduced and glutamate levels increased in IUD mice. Kainate receptor binding to hippocampal synaptosomal membranes from IUD mice at 30 d of age was significantly increased. There was also an enhanced 45Ca influx into cortical and hippocampal slices of these mice. These findings suggest that intrauterine exposure to domoic acid can induce hippocampal excitotoxicity by increasing the neuronal calcium influx through kainate receptor activation. Histological changes suggest progressive hippocampal damage in IUD mice, but without overt clinical seizures.

Aging↗
PubMed1992

Case report 747: Leiomyosarcoma of great saphenous vein.

Vena caval leiomyosarcomas are rare tumors; noncaval leiomyosarcomas are even less common and are rarely diagnosed preoperatively. We present a case of leiomyosarcoma of the great saphenous vein that was diagnosed by MRI based on its appearance and location. The presence of an intraluminal tumor in a vein on MRI should suggest the diagnosis of leiomyosarcoma of the vein, allowing definitive operative excision. With widespread use of MRI for indeterminate soft-tissue masses, we anticipate presurgical diagnosis of venous leiomyosarcoma will be made with increasing certainty and frequency.

Female↗