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Biomedical subjects

J S Nelson

Publications and source records attributed to J S Nelson.

At least 163 records · Page 9Linked to original sources
PubMed1980

Spinal cord infarction in a patient with sickle cell anemia.

The most common serious neurologic complication of sickle cell anemia is occlusive vascular disease with central nervous system infarction. The parenchymal lesions are most often located in the brain, chiefly within major cerebral arterial boundary zones. Spinal cord infarction is extremely rare. We report a patient with sickle cell anemia who developed an acute cervical myelopathy. At autopsy, there was a spinal cord infarction with extensive involvement of the rostral cervical segments. Recanalized thrombi were present in the right vertebral artery and smaller subarachnoid arterioles adjacent to the infarcted cord. This is the first report of autopsy-confirmed spinal cord infarction associated with sickle cell anemia.

Adult↗
PubMed1979

Defective activation of the pyruvate dehydrogenase complex in subacute necrotizing encephalomyelopathy (Leigh disease).

Autopsy examination confirmed the diagnosis of subacute necrotizing encephalomyelopathy (SNE) in a 7-month-old male infant who underwent several metabolic studies before death. Intermittent lactic acidemia and fumaric aciduria, an extreme hyperglycemic response to an intravenous bolus of alanine, and an elevated total body flux rate of glucose (58.4 mumoles . kg-1 . min-1) suggested a disturbance in the oxidative decarboxylation of pyruvate. Enzymological studies of postmortem samples revealed low nonactivated pyruvate dehydrogenase activity in liver (19.4%) and brain (53.8%). The lowest brain pyruvate dehydrogenase activities were noted in the midbrain and pontine regions. Supramaximal activation of the hepatic pyruvate dehydrogenase complex (135% of control values) occurred in vitro. Spontaneous reactivation following in vitro inactivation of the complex with adenosine triphosphate was significantly less (p less than 0.02) in the patient's samples compared to controls. The biochemical defect was not apparent in fibroblasts. These enzymological observations point to an in vivo defect in the activation mechanism of the pyruvate dehydrogenase complex as the biochemical disturbance in SNE. The findings suggest that dichloroacetate may be beneficial in treating SNE.

Alanine↗
PubMed1979

Congenital astrocytoma presenting with intracerebral hematoma. Case report.

A massive left intracerebral hematoma was surgically evacuated from a 2-week-old infant. Pathological examination showed that the hemorrhage had developed within a fibrillary astrocytoma. Neonatal intracerebral hemorrhage should raise the question of congenital tumor because such a hemorrhage in this age group is rarely the result of trauma, bleeding diathesis, or vascular malformation.

Astrocytoma↗
PubMed1978

Atypical neuronal ceroid-lipofuscinosis.

We describe the clinical, pathologic, and ultrastructural findings in a case of juvenile onset neuronal ceroid-lipofuscinosis without visual symptoms or retinal abnormalities. The histochemical and ultrastructural characteristics of the neuronal lipopigment were similar to those in typical cases of neuronal ceroid-lipofuscinosis. Atypical neuronal ceroid-lipofuscinosis may be distinguished histochemically, ultrastructurally, and clinically from another disorder called juvenile dystonic lipidosis, with which it has been confused.

Adolescent↗
PubMed1977

Leukoencephalopathy in childhood leukemia.

A 14-year-old boy survived for 7 years after the initial diagnosis and treatment of acute lymphocytic leukemia. Neurologic deterioration occured repeatedly throughout his complicated clinical course but it was most severe and only partially reversible following orally administered pyrimethamine. The neuropathologic lesions were distinctive and included a diffuse reactive astrocytosis, axonal degeneration, status spongiosis, circumscribed foci of demyelination and coagulative necrosis, and mural thickening with luminal narrowing of microcirculatory vessels. This collection of findings represents the leukoencephalopathy of childhood leukemia that we and others believe results in large part from the combined effects of cranial irradiation and chemotherapy. The role of folic acid antagonists, namely methotrexate and pyrimethamine, are particularly noteworthy in this regard.

Adolescent↗
PubMed1977

Oral vaccination and multivalent vaccine against Pseudomonas aeruginosa keratitis.

Active immunization against Pseudomonas aeruginosa keratitis and systemic disease in mice was studied. In the first series of experiments, monovalent vaccine, administered orally or intraperitoneally, protected against subsequent corneal and intraperitoneal challenge with the homologous strain of P. aeruginosa; however, oral administration of vaccine elicited less protection than intraperitoneal administration. After both routes, protection was observed at 11 and 32 days post-vaccination, but it was greater at 11 days. In the second series of experiments, multivalent vaccine administered intraperitoneally protected against corneal challenge with 56 to 78 percent of 18 strains.

Administration, Oral↗
PubMed1976

The pathologic characteristics of leukostasis and leukemic nodules occurring in the central nervous system of guinea pigs with L2C/NB leukemia.

Leukostasis and leukemic nodules are found in the central nervous system (CNS) of at least 75% of guinea pigs during the terminal stages of untreated L2C/NB leukemia, a transmissible, acute lymphocytic leukemia. The CNS lesions develop after extensive visceral leukemic infiltration at a time when the white cell count is rising to 10(5)-5 x 10(5) cells/mm3, and the differential examination shows predominantly blasts. Leukostasis precedes formation of the nodule. Both lesions may be found in any part of the central nervous system including the spinal cord, but are most numerous in the diencephalon and rostral brain-stem. Ultrastructural studies demonstrate that parenchymal leukostasis develops chiefly within capillaries, and is associated with endothelial cell degeneration and necrosis. Fibrin deposits are not seen within affected capillaries. The sequence of development, pathologic and hematologic characteristics of leukostasiss and leukemic nodules in human and L2C/NB leukemia are virtually identical. The CNS lesions of untreated L2C/NB leukemia are a precise, convenient model for the study of intracerebral leukostasis and leukemic nodules.

Animals↗
PubMed1976

Mechanisms underlying reduced growth rate in C3HBA mammary adenocarcinomas recurring after single doses of x-rays or fast neutrons.

C3HBA mammary tumors were irradiated with 3000 rads of 250-kVp X-rays or 1000 rads of 8-MeV neutrons, doses of radiation matched for producing equal growth delay. At 14 days postirradiation, tumors were regrowing at a reduced rate relative to controls. Cell kinetic parameters were examined using percentage of labeled mitoses techniques, and blood vessel spacing and tumor architecture were examined histologically to determine whether the mechanisms underlying growth rate changes were the same after neutron as after photon irradiation. The tumor volume-doubling time at 14 days posttreatment is similar in both irradiated groups (TD=117 hr for neutron-irradiated tumors, 132 hr for X-irradiated tumors) and is approximately twice as long as the doubling time of 61.4 hr in control tumors in the same size range. Control and X-irradiated tumors have median cell cycle durations of 19.3 and 18.5 hr, respectively; the more slowly growing X-irradiated tumors have a reduced growth fraction and increased cell loss factor. Regrowing neutron-irradiated tumors have a median cell cycle of 27.2 hr, with calculated growth fraction and cell loss factor values intermediate between those for control and X-irradiated tumors. Scatter in the percentage of labeled mitoses data makes it difficult to determine whether the cell cycle durations are significantly different. The average distance from tumor parenchymal interphase cells to the nearest recognizable blood vessel is nearly identical in the two irradiated groups and for both groups is significantly greater than interphase to vessel distance in controls. The average distance in irradiated tumors approaches the maximal distance for O2 diffusion in mouse adenocarcinomas of a corded structure surrounding a central blood vessel. Both neutron- and X-irradiated tumors contain more necrosis and fewer viable-appearing parenchymal cells than do control tumors of the same size. The similar growth rate and growth delay in this tumor after 3000 rads of X-rays of 1000 rads of neutrons occur in the face of possibly different cell cycle durations and seem related to similar circulatory system inadequacies which limit growth and are expressed as greater average cell-to-blood-vessel distance and increased cell loss leading to necrosis, indicating oxygen or nutrient deprivation.

Adenocarcinoma↗
PubMed1976

Estimation of tumor growth fraction in murine tumors by the primer-available DNA-dependent DNA polymerase assay.

The tumor growth fraction measured by the percentage labeled mitoses method has been determined in transplantable solid and ascites murine tumors, the latter being measured at different times after transplantation. These values were compared to an in vitro, autoradiographic assay that determines the fraction of cells in a given population (primer-available DNA-dependent DNA polymerase index) that have both nuclear DNA-dependent DNA polymerase and DNA capable of acting as primer-template. It appears that almost all cells with a short G1 phase duration (less than 19 hr) that are within the proliferative cycle are primer-available DNA-dependent DNA polymerase positive. The results of the comparison indicate that the primer-available DNA-dependent DNA polymerase index estimation of growth fraction is very nearly identical to the growth fraction measured by the percentage labeled mitoses method.

Animals↗
PubMed1975

Asymptomatic destruction of the fornix in man.

In the five previous reports dealing with the effects of interruption of the formix in man, two noted that a severe disturbance of recent memory resulted, and three indicated that no symptoms were evident. The brain was examined in only one of the cases cited. This report describes a patient, without any apparent neurological or psychological disturbances, in whom a malignant tumor had destroyed the formix bilaterally.

Adenocarcinoma↗