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Biomedical subjects

J J Townsend

Publications and source records attributed to J J Townsend.

At least 37 records · Page 2Linked to original sources
PubMed1993

A phase II evaluation of tamoxifen in unresectable or refractory meningiomas: a Southwest Oncology Group study.

Twenty-one patients with nonresectable refractory meningiomas were registered on a study giving tamoxifen 40 mg per M2 b.i.d. for four days, then 10 mg b.i.d. thereafter. Nineteen were eligible and evaluated for response. One patient (5%) achieved an MRI-documented partial response while two had a minor response measured on CT scan which was of short duration (4 and 20 months). Six patients (32%) remained stable for a median duration of 31 + months while ten (53%) demonstrated progression. Twenty-two percent (22%) reported subjective improvement though this did not correlate with objective improvement in all cases. At present, a definite recommendation for the use of tamoxifen in refractory meningiomas cannot be made. Further evaluation of hormonal therapy of meningiomas with a consensus for definition of endpoints for evaluation of response in view of the difficulty of evaluating radiologic findings with clinical outcome, is needed.

Female↗
PubMed1993

Augmentation of adoptively transferred experimental allergic encephalomyelitis by administration of a monoclonal antibody specific for LFA-1 alpha.

We investigated the effect of an anti-leukocyte function antigen 1 (LFA-1 alpha) monoclonal antibody, M17/4.2, on murine relapsing experimental allergic encephalomyelitis (EAE). In vitro investigations demonstrated that M17/4.2 inhibited proliferation with concanavalin A or myelin basic protein. Control mice treated with phosphate buffered saline (PBS) developed a mild to moderate disease at 7-10 days followed by a long-term relapsing clinical course. With administration of M17/4.2, the time of disease onset was unchanged; however, the severity of the disease was greatly augmented, resulting in early mortality. The pathology correlated well with the clinical course. M17/4.2 mice showed more inflammation and demyelination than PBS or anti-CD4 treated mice. Therefore, this anti-LFA-1 specific monoclonal antibody augmented EAE.

Animals↗
PubMed1993

Symptomatic hyponatraemia: can myelinolysis be prevented by treatment?

The treatment of hyponatraemia is controversial because of the risk of causing central or extrapontine myelinolysis (EPM). Rapid correction with hypertonic saline to a low normal sodium level has its proponents; others feel that slow correction to below normal sodium values is preventative. Most investigators feel that overcorrection should be avoided. It is not known whether the magnitude of serum sodium change is more important than the actual rate of correction. We present three patients with hyponatraemia ranging from 103 to 105 mmol/l who were corrected slowly with normal saline, corrected quickly with hypertonic saline, or rapidly overcorrected with hypertonic saline. All became comatose and died; all had EPM with or without central pontine myelinolysis (CPM). The rate of correction, the solution used, or the magnitude of correction did not seem to protect against demyelination. In a review of 67 reported CPM cases since 1983, no patients documented as having CPM or EPM by radiological studies or necropsy were treated with water restriction only. A group of 27 hyponatraemic patients treated only with water restriction and 35 with diuretic cessation alone did not develop CPM or EPM. This may be a reasonable approach to patients with symptomatic hyponatraemia and normal renal function.

Adult↗
PubMed1993

A randomized trial of radiotherapy versus radiotherapy plus CCNU for incompletely resected low-grade gliomas: a Southwest Oncology Group study.

Sixty adult patients with incompletely excised low-grade gliomas were randomly assigned to receive radiotherapy (55 Gy over a total of 6 1/2 to 7 weeks) either alone or with 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU; 100 mg/sq m every 6 weeks). Pathological review showed that six patients were ineligible for the study. Evaluation of patient age, extent of surgery, tumor grade, and performance status showed no significant differences between the treatment arms. The response rate, as judged by the disappearance or reduction in size of the tumor on computerized tomography scans, was 79% for radiation therapy alone versus 54% for irradiation plus CCNU. The median survival time was 4.45 years for all patients, with no significant difference between treatment arms (p = 0.7). For the group as a whole, patient age and performance status were the most important prognostic parameters. The majority of patients receiving chemotherapy experienced moderate hematological toxicity. This study demonstrates that CCNU chemotherapy does not improve the results of radiation therapy in the treatment of incompletely excised low-grade gliomas.

Adult↗
PubMed1992

Intrapulmonary neuroglial heterotopia.

Nonteratomatous intrapulmonary neuroglial heterotopia not associated with birth trauma or frank vascular embolization has been described rarely. This article briefly reviews the literature, and presents two additional cases of intrapulmonary neuroglial heterotopia. We found 14 cases in the literature. Twelve of these cases had central nervous system disruption, where neuroglial elements were in direct contact with amniotic fluid. Several hypotheses have been proposed, including fetal aspiration of detached neural fragments within amniotic fluid, neural crest migration defects, and vascular embolization with implantation. Of our two cases, one represents the first occurrence where central nervous system abnormalities were secondary to mechanical disruption, rather than to a primary neural tube defect. Our second case represents the youngest documented occurrence (17 weeks gestation) of intrapulmonary neuroglial heterotopia. Additionally, immunohistochemical studies were performed on these lesions, the results of which favor their neural origin. We present these findings and suggest they support the aspiration mechanism for neuroglial heterotopia in lung tissue.

Abnormalities, Multiple↗
PubMed1991

Cerebral granular cell tumor occurring with glioblastoma multiforme: case report.

A 65-year-old man presented with 4 weeks of partial right visual field loss. A left occipital granular cell tumor was diagnosed via open biopsy. No specific tumoricidal therapy was given, and the patient returned 2 weeks later with fluent dysphasia and mild right hemiparesis, and formed visual hallucinations. A large left parietotemporal mass, separate from the granular cell tumor, was diagnosed as a glioblastoma multiforme by stereotactic biopsy. The histogenesis of cerebral granular cell tumors is controversial; this case supports recent speculation of their possible glial origin.

Aged↗
PubMed1991

Chimeric cytotoxin IL2-PE40 inhibits relapsing experimental allergic encephalomyelitis.

IL2-PE40 is a chimeric protein composed of human interleukin-2 (IL2) genetically fused to a modified form of Pseudomonas exotoxin lacking the cell recognition domain. IL2-PE40 is cytotoxic for IL2 receptor-bearing lymphocytes in culture and can inhibit activation of T cells in vivo. IL2-PE40 can significantly diminish antigen-stimulated proliferation of lymphocytes sensitized to myelin basic protein. Intraperitoneal administration of IL2-PE40 not only markedly inhibits the clinical manifestations of adoptively transferred relapsing experimental allergic encephalomyelitis but also dramatically reduces both inflammation and demyelination characteristic of the disease.

Animals↗
PubMed1991

Neurenteric cysts of the posterior fossa: recognition, management, and embryogenesis.

Neurenteric cysts are endothelium-lined structures most commonly encountered in the lower cervical or upper thoracic spinal cord. The occurrence of neurenteric cysts within the cranial vault is unusual. We present three patients with neurenteric cysts located within the posterior fossa: one near the jugular foramen deforming the 4th ventricle, a second in the cerebellopontine angle, and a third in the prepontine cistern. Several different theories have been advanced to explain the embryogenesis of neurenteric cysts. We review these theories and conclude that cranial neurenteric cysts may arise from a disturbance of early gastrulation, shortly after the onset of primitive streak regression.

Adult↗
PubMed1989

Porphyrin-laser photodynamic induction of focal brain necrosis.

A noninvasive photodynamic method has been developed to produce focal brain necrosis using porphyrin activated in vivo with laser light. After peripheral injection of the photosensitive porphyrin derivative, Photofrin I, mice were irradiated on the posterior lateral aspect of the head through the intact depilated scalp with 632 nm argon-dye laser light. Animals were studied at one, two and seven days after irradiation. Blood-brain barrier damage was detected by the intravenous injection of Evans blue, horseradish peroxidase and heterologous immunoglobulins. At one and two days after irradiation, the lesions were characterized by extravasation of immunoglobulin and Evans blue, and by edema, ischemia and infiltration by monocytes. On the seventh day after irradiation, the lesion was smaller than it had been two days after irradiation, and had reactive changes at its edges and coagulative necrosis at its center. Extravasation of Evans blue and immunoglobulin was markedly reduced by the seventh day after irradiation, but uptake of horseradish peroxidase by macrophages located at the periphery of the lesion was evident.

Animals↗
PubMed1986

Central neurocytoma--a rare benign intraventricular tumor.

Two cases of Central neurocytoma arising in the lateral ventricles are presented. Both patients had well-circumscribed masses in the right lateral ventricle causing hydrocephalus. The tumors were composed of small round cells forming Homer Wright rosettes against a fine fibrillary background. In one patient surgical removal was complete and no recurrence has been noted approximately one year later. These tumors appear to be benign and complete surgical excision should be curative.

Adult↗
PubMed1986

Peripheral nervous system demyelination with herpes simplex virus.

Inoculation of the cornea or footpad with herpes simplex virus Type I (HSV) has been shown to produce subsequent encephalitis or myelitis respectively. Although Schwann cells become infected, there is no destruction or demyelination in the peripheral nervous system (PNS). Demyelination only occurs in the central nervous system. Previous studies have shown that the Schwann cells infected with HSV do not produce enveloped viral particles. The studies presented here demonstrate that microinjection of HSV into the sciatic nerve of mice causes focal mononuclear cell infiltration and demyelination seven days after injection. The Schwann cells in this model produced enveloped virus. These studies demonstrate that when HSV is introduced into the extracellular space of the PNS, demyelination occurs.

Animals↗
PubMed1985

A cell kinetic study on medulloblastomas.

The cell kinetics of medulloblastoma were studied to define characteristic proliferation for comparison with other neuroectodermal tumors. Four patients with cerebellar medulloblastoma received 3H-thymidine intravenously 1 to 2 days before surgery. Biopsy specimens from each tumor were processed for autoradiography. The respective average labeling indices were 14.4%, 14.1%, and 11.2% in the three mid-cerebellar medulloblastomas and 8.0% in the cerebellar hemispheric medulloblastoma. The mean survival time with various treatments including radiation therapy before or after the study in these four patients was 6 years (range, 3-9 years). In contrast, patients with malignant gliomas that had a labeling index greater than 5% died within 1 year. This difference in survival was attributed to the greater sensitivity of medulloblastoma to radiation therapy.

Adolescent↗
PubMed1985

Alexander's disease.

This is the first pathologic report of an infant at 37 weeks' gestation with Alexander's disease. The findings demonstrate that the disease can arise in utero and be extensive at birth before myelination begins.

Adult↗