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Biomedical subjects

J B Posner

Publications and source records attributed to J B Posner.

At least 217 records · Page 12Linked to original sources
PubMed1977

Experimental spinal cord compression by epidural neoplasm.

We have developed an experimental model of spinal cord compression in rats. Tumor injected anterior to the T-12 vertebral body grows through the intervertebral foramina to compress the cord and produces paraplegia in 3 to 4 weeks. Evidence for vasogenic edema in spinal cord compressed by tumor includes increased water content, leakage of horseradish peroxidase into gray matter, and histologic evidence of edema. The vascular supply to the cord overlying the tumor appears to be compromised. Both spinal cord edema and clinical symptoms are lessened by treating symptomatic animals with dexamethasone.

Acute Disease↗
PubMed1977

The effect of oral glycerol on intraventricular pressure in man.

Oral glycerol was administered to eight patients with meningeal carcinomatosis or acute leukemia in whom ventricular catheters and Ommaya reservoirs had been implanted for the purpose of intrathecal chemotherapy or chemoprophylaxis. Intraventricular pressure was monitored continuously via the Ommaya reservoirs before and after single doses of 0.5, 1.0 or l.5 gm per kilogram of body weight. The interrelationship between initial pressure, change in pressure, serum osmolarity, and duration of action was investigated, and the ratio of CSF-to-plasma osmolarity was determined 4 to 5 hours after glycerol administration. The effects of chronic 6-hourly and 4-hourly 1 gm per kilogram glycerol doses were studied in a patient with meningeal carcinomatosis and increased intracranial pressure. Our data suggest that as a cerebral dehydrating agent oral glycerol is most effective in patients with markedly increased intracranial pressure. A single 1 gm per kilogram dose is adequate to lower raised intraventricular pressure acutely, but its effect is short-lived. Continuous oral administration must be carefully monitored to avoid the establishment or a reverse osmotic gradient, secondarily increased intracranial pressure, and clinical deterioration.

Administration, Oral↗
PubMed1977

Treatment of experimental spinal cord compression caused by extradural neoplasms.

Epidural spinal cord compression was produced in rats by injection of Walker 256 carcinoma cell suspension anterior to the T-12 or T-13 vertebral body. The tumor grows through the intervertebral foramina to compress the spinal cord and produce paraplegia in 3 to 4 weeks. The effect of several treatments upon clinical signs was assessed. Dexamethasone caused a significant but transient improvement in neurological function. Radiation therapy likewise improved neurological function, and was more effective when given by a high-dose protracted course than when given either in a single dose or a low-dose protracted course. Laminectomy was not helpful in relieving neurological symptoms. Dimethyl sulfoxide did not relieve neurological symptoms. Cyclophosphamide was most effective in relieving neurological symptoms, and most of the animals that were treated with that drug when they were severely weak but still able to move their hind limbs recovered fully. Some animals that were totally paraplegic when treatment began recovered function after radiation therapy or cyclophosphamide treatment, but recovery was better if treatment was started when animals could still move their hind limbs. This animal model appears to be a useful way of studying the treatment of human spinal cord compression produced by epidural neoplasms.

Animals↗
PubMed1977

In vitro lymphocyte transformation of MS patients to paramyxovirus antigens.

The immune response of 21 MS patients and 21 healthy volunteers was tested in vitro lymphocyte transformation assay. The stimulating antigens were measles, mumps, parainfluenza, E. coli, S. aureus and C. albicans. MS patients were found to respond similarly to the normal controls to all antigens tested with the exception of mumps antigen. The maximum responses of the MS patients to this antigen were significantly lower than those observed for the normals. However, since 95 per cent of the MS lower maximum responses were still within the positive range, the immunological significance of this phenomenon will require further clarification.

Antigens, Viral↗
PubMed1975

Clinical evaluation of the unconscious patient.

A systematic approach in the differential diagnosis of the comatose patient, based on the pathophysiological classification of the various disorders causing coma and the clinical neurological examination, is outlined. This approach appears useful in that in most instances a clinical diagnosis suggesting the pathophysiological abnormality producing coma can be made. Appropriate laboratory tests can then be selected to establish a definitive etiological diagnosis. Such a systematic approach to the evaluation of the comatose patient hastens definitive therapy in a disorder where time in which to institute therapy is often short.

Aged↗
PubMed1975

Detection of measles antibodies in cerebrospinal fluid and serum by a radioimmunoassay.

Evidence that different structural components of the measles virus may act as antigens has been provided by the serologic methods of hemagglutination inhibition hemolysin inhibition, and nucleocapsid complement fixation. Using radioiodinated measles viral antigens, and immune precipitation assay has been designed that is capable of discriminating among various reactivities to measles viral structural components in serum or cerebrospinal fluid (CSF) and of distinguishing whether IgG and IgM antibody is involved. This technique has been applied to the study of measles antibodies in CSF and sera of patients with multiple sclerosis (MS) and other neurologic diseases. From data presented here, it was found that both groups of patients have individual reactivity to measles proteins, present in CSF and serum, whereas three normal CSF samples were found not to have such antibodies. It appears that oligoclonal immunoglobulins in CSF of MS patients may be detected by this method, and one patient with MS was found to have CSF IgM anti-measles antibodies.

Antibodies, Viral↗
PubMed1975

Does pseudotumor cerebri cause the empty sella syndrome?

Eight patients had both the "primary empty sella syndrome," diagnosed by the finding of an air-filled sella turcica at pneumoencephalography, and pseudotumor cerebri, diagnosed by the finding of an elevated cerebrospinal fluid pressure in the presence of normal ventricular size and position on pneumonencephalography. All eight patients were obese women, and six were hypertensive. Six complained of headaches and menstrual irregularities, and two were asymptomatic. Three had visual symptoms and four had papilledema at the time of examination. These two clinical disorders appear to be frequently related, and when they are related, visual field defects and visual loss are more likely to occur than when either entity appears alone. Chronically increased intracranial pressure from pseudotumor cerebri may produce an empty sella if the diaphragma sella is incompetent and the subarachnoid space herniates into the sella turcica.

Adult↗
PubMed1975

Neurologic manifestations of intravascular coagulation in patients with cancer. A clinicopathologic analysis of 12 cases.

Among 1,459 autopsied patients with cancer, 12 had multifocal infarcts of the brain that appeared to be caused by intravascular coagulation. Most of these patients were women with leukemia or lymphoma, and all had a clinical course in which neurologic signs and symptoms were prominent. All had evidence of generalized brain disease (delirium and stupor or coma), and several also had focal brain disease (focal seizures, hemiparesis). All patients had laboratory evidence of coagulation abnormalities, although these were often not severe when neurologic symptoms began. Pathologically, there were multifocal hemorrhagic or ischemic infarcts in the distribution of several cerebral vessels, without a systemic source for cerebral emboli. Fibrin thrombi were identified in cerebral vessels and in vessels of several other organs. The clinical findings fit the pathologic picture, and in most instances the correct diagnosis might have been made earlier had it been considered.

Adolescent↗