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Biomedical subjects

J B Posner

Publications and source records attributed to J B Posner.

261 records · Page 15Linked to original sources
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Meningeal carcinomatosis: development of an experimental model.

An experimental model of meningeal carcinomatosis has been produced by intracisternal inoculation of Walker 256 carcinoma cell suspension into Wistar rats. The tumor grows rapidly and is fatal in about 15 days if 10(6) cells are injected. The histopathological pattern observed is similar to that seen in diffuse leptomeningeal involvement of systemic cancer in human beings. The model will be useful for investigating the pathophysiology of the neurological disability produced by meningeal carcinomatosis and the efficacy of chemotherapeutic agents.

Animals↗
PubMedDate not supplied

Colonic ileus complicating laminectomy.

Colonic ileus is an unusual form of adynamic ileus that often mimics true intestinal obstruction and that, if not recognized and adequately treated, may be fatal. We have encountered three patients in whom this syndrome followed apparently uncomplicated laminectomy for herniated disc or spinal stenosis. Two of our three patients required abdominal exploration for diagnosis and treatment of the complication. At operation, a large distended colon without volvulus or tumor was found. Cecostomy was performed in both patients. The third patient was treated conservatively. All three patients recovered without sequelae. The pathogenesis of the illness is unknown, but the most widely held view is that ileus results from increased sympathetic activity that inhibits the bowel. Conservative management consisting of correction of any fluid or electrolyte abnormalities, continuous gastric suction via nasogastric tube, and placement of a rectal tube may relieve the symptoms. Patients should, however, be followed carefully and, if distention of the cecum exceeds 12 cm, a decompressive operation is indicated.

Aged↗
PubMedDate not supplied

Brain tumors.

At the same time that studies indicate an increase in the frequency of brain tumors, improvements in diagnosis and treatment have increased the clinician's ability to deal with these cancers. Dr. Posner, Chairman of the Department of Neurology at Memorial Sloan-Kettering Cancer Center in New York City, encourages physicians to be alert for symptoms of brain tumors, to be positive about treatment, and to be prepared to refer patients to investigative treatment so that progress can continue.

Adult↗
PubMedDate not supplied

MR imaging of brainstem tumors.

Eighteen patients aged 4-72 years old with brainstem tumors were studied using a 0.5 T magnetic resonance (MR) imager and a third- or fourth-generation computed tomographic (CT) scanner. MR imaging showed the brainstem to be enlarged on sagittal views in all cases; exophytic growth was seen in eight. Alterations of signal intensities were shown in most cases on spin-echo sequences using 30 and 90 msec echo times and inversion recovery techniques. It was not possible to distinguish primary from metastatic tumors. The configurations and margins of the areas with abnormal signal did not appear to correlate with the clinical behavior of the tumors. CT was able to recognize brainstem tumor in only 13 of 16 cases. In the two cases of metastases, plain CT scans were normal, but enhancement was seen after administration of contrast material in one. It appears that MR imaging is sensitive in detecting tumor enlargement and abnormal signals and is superior to CT in evaluating brainstem tumors.

Adolescent↗