Search PubMed⌕ Search

Biomedical subjects

J B Posner

Publications and source records attributed to J B Posner.

At least 199 records · Page 11Linked to original sources
PubMed1979

Enhancement of CNS penetration of methotrexate by hyperosmolar intracarotid mannitol or carcinomatous meningitis.

Intracarotid (i.c.) hyperosmolar mannitol enhances central nervous system (CNS) penetration of intravenous (i.v.) methotrexate (MTX) in normal adult rats. A fivefold augmentation in the CSF:serum and ipsilateral brain:serum MTX concentration ratios was observed 1 hour after drug administration. Intravenous mannitol had no such effect. Rats with meningeal carcinomatosis have a partial defect in blood-brain barrier function, and the CSF:serum MTX concentration ratio was 4.6 times higher in these animals than in normal rats prior to mannitol therapy. Intracarotid hyperosmolar mannitol further augmented the blood-brain barrier permeability to intravenous MTX. Intracarotid mannitol increased the therapeutic effect of MTX, since rats with meningeal carcinomatosis that received i.v. MTX and i.c. mannitol experienced a slight enhancement in survival.

Animals↗
PubMed1978

Epidural spinal cord compression from metastatic tumor: diagnosis and treatment.

The clinical findings in 130 conseucutive cases of spinal cord compression by metastatic extradural tumors were analyzed. These 130 patients were combined with a previous survey of 105 patients to compare the effectiveness of radiation therapy (RT) alone with that of surgical decompression followed by RT. Ambulation after treatment was considered a successful outcome. The most common primary tumors producing spinal cord compression were (in order) breast, lung, prostate, and kidney. In 68% of these tumors the thoracic region was involved. Pain was the primary symptom of 96% of the patients, while motor or sensory deficits (or both) were found in 82% of them. Therapy consisted of surgery and RT in 65 patients and RT alone in 170 patients. There were no differences in outcome between those treated by surgery combined with RT and those managed by RT alone. Patients with radiosensitive tumors and those ambulatory at the onset of treatment benefited whether treated by surgery or by RT. Seventy-five percent of living patients who improved from treatment remained ambulatory at 6 months, and approximately 50% of living patients were ambulatory at 1 year. We conclude that RT without decompressive laminectomy is as effective as decompressive laminectomy in treating epidural spinal cord compression from systemic cancer.

Adolescent↗
PubMed1977

Central nervous system infections in patients with cancer. Changing patterns.

Central nervous system infections in patients with cancer at Memorial Sloan-Kettering Cancer Center from 1971 to 1974 were surveyed and compared with a previous survey from 1955 to 1970. The two periods were similar in that: 1) There was a high incidence of CNS infection in patients with lymphoma, leukemia, and head and spine tumors, 2) specific organisms tended to infect patients with certain primary neoplasms, and 3) fungal infections were common and difficult to diagnose. The two periods differed in that: 1) the overall incidence of CNS infection was lower in 1971 to 1974, 2) there was a decreased incidence of cryptococcal meningitis, and 3) there was an increase in Listeria monocytogenes meningitis. Early recognition of CNS infection and aggressive therapy appears to increase survival.

Bacterial Infections↗
PubMed1977

Cerebral necrosis following radiotherapy of extracranial neoplasms.

We have examined 6 patients with delayed cerebral necrosis following irradiation of extracranial neoplasms. Four of the 6 patients received 1,760 rets (or less) tumor dose. The initial symptoms attributable to radiation necrosis appeared 4 to 31 months after irradiation and were those of a focal supratentorial mass. Cerebral angiography delineated an avascular frontal or temporal lesion in all 6 patients; in 1 case a magnification study revealed narrowing, irregularity, and occlusion of small cortical vessels. Four of our 6 patients underwent craniotomy with partial or complete surgical extirpation of necrotic brain tissue. Two operated patients are alive and without disabling neurological symptoms 30 and 25 months, respectively, after the operation. The characteristic neuropathological features of delayed radiation necrosis of brain suggest that vascular injury rather than neuronal or glial damage is of primary pathogenetic significance.

Adult↗
PubMed1977

Subacute sensory neuropathy: a remote effect of carcinoma.

Seven patients with subacute sensory neuropathy are described and the findings in 29 previously reported patients are reviewed. The presence of this characteristic neurological disorder strongly suggests an accompanying neoplasm. Five of 7 patients had cancer, and 4 died. Autopsy was performed on 3, and pathological analysis revealed inflammation and degeneration of dorsal root ganglia and degeneration of posterior roots and posterior columns of the spinal cord. The dorsal root ganglion was biopsied in 4 patients and showed similar inflammatory lesions. Electron microscopical studies showed inflammation and neuronal degeneration. No viral particles were seen. Viral cultures of the biopsied ganglia from 4 patients were negative. Antineuronal antibodies were not detected in 2 patients. The cause of this syndrome is unknown, and no treatment has been successful.

Adenocarcinoma↗
PubMed1977

Metastic tumor of the brain: development of an experimental model.

The injection of a suspension of Walker 256 carcinoma cells into the carotid artery of rats produced a model of hematogenously spread cerebral metastases. Most animals died from massive extracerebral tumors of the head and jaw; brain tumors were present in only one-quarter. External carotid artery ligation prior to tumor inoculation did not increase the incidence of fatal brain tumor. When cyclophosphamide, 15 mg/kg, was injected as a single dose on the fourteenth day after tumor inoculation, most of the extracerebral tumor disappeared. Fifty percent of the animals so treated were cured of tumor, but 90% of the remainder died of large intracerebral tumors. Severe cytopathic changes resulting from cyclophosphamide were present in extracerebral or choroid plexus tumors but were mild or nonexistent in intracerebral tumors. These selective effects of cyclophosphamide suggest that water-soluble agents are less effective against tumor in the brain than against extracerebral tumors despite the fact that metastatic tumor breaks down the blood-brain barrier.

Animals↗
PubMed1977

"Disappearing" spinal cord compression: oncolytic effect of glucocorticoids (and other chemotherapeutic agents) on epidural metastases.

Four patients suffering spinal cord compression resulting from epidural metastases were treated with adrenocorticosteroid hormones. For 2 patients, prompt relief of symptoms followed glucocorticoid therapy alone and was associated with marked shrinkage or disappearance of the metastasis, a direct oncolytic effect of the steroids. For the other 2 patients, glucocorticoids combined with other chemotherapeutic agents caused disappearance of the extradural tumor. For 1 patient, failure to recognize the oncolytic effects of the chemotherapy led to an unnecessary surgical procedure, and for a second patient an unnecessary operation was narrowly averted. Thus, for certain patients, glucocorticoids may occasionally have a marked oncolytic effect on epidural metastatic tumors.

Adolescent↗