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Biomedical subjects

E L Hogan

Publications and source records attributed to E L Hogan.

At least 145 records · Page 8Linked to original sources
PubMed1980

Serum gangliosides in cerebral astrocytoma.

The serum concentration and composition of gangliosides were examined in 80 humans including 10 normal subjects. A significant increase was found in the total gangliosides of serum in 7 patients with cerebral astrocytomas. There was also an increased percentage of serum gangliosides with simpler structure, particularly GM3. The serum of patients with other intracranial tumors, including pituitary adenomas, ependymoma, teratoma, and metastases, did not show an increase in total ganglioside; however the pattern of simplification was found in these and in a few patients with extracranial tumors as well. The findings suggest that astrocytoma tumors shed sialoglycolipids into the circulation, and their assay may be useful in monitoring oncological therapy.

Astrocytoma↗
PubMed1980

The effects of spinal cord trauma on myelin.

Experimental spinal cord trauma was produced in rats by dropping a 10-g weight from a height of 30 cm upon exposed spinal cord. The histological lesion consisted of edema, necrosis, and hemorrhage. The fine structure of the early traumatic lesion (4 to 12 hours) included granular dissolution of axons and a characteristic vesiculation of myelin. The predominant ultrastructural features of older lesions (12 to 72 hours) were intra-axonal calcification and lipid-laden macrophages. The yield of myelin and the activity of adenosine 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP) were reduced by approximately 15% at 4 hours and by 60% at 72 hours. Losses in all myelin proteins were observed, but were most severe and occurred earliest in the basic proteins. The ultrastructural and biochemical alterations observed in this study indicate that proteinase activity is increased and may be partially responsible for the traumatic myelinolysis in experimental spinal cord trauma.

Animals↗
PubMed1980

Gangliosides of human cerebral astrocytomas.

Ganglioside content and composition were examined in a series of 25 human gliomas, which were graded histologically by the criteria of Kernohan. The concentration of total gangliosides (lipid-bound sialic acid [LBSA]) was decreased with respect to normal brain tissue in nearly all tumors, and the extent of reduction correlated with the stage of tumor anaplasia. The distribution of individual gangliosides was altered in glial tumor tissue with an increase in proportion of the structurally simple gangliosides and reduction of polysialogangliosides. The most consistent and significant difference was the elevation of proportion of ganglioside GD3 from 4-5% of total LBSA in normal brain to 20% in the astrocytoma grade IV. The proportions of gangliosides GM2 and GD2 were also found to be elevated in all grades of the tumors. The simplification of ganglioside composition seems to be associated with transformation of the astrocyte with the accumulation of the simpler gangliosides, since the changes resemble those reported with in vitro transformation rather than those of analyses of preparations of purified glial cells.

Astrocytoma↗
PubMed1979

Activity of 2',3'-cyclic nucleotide 3'-phosphohydrolase in human cerebrospinal fluid.

Activity of the myelin marker enzyme 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP) was assayed in cerebrospinal fluid samples obtained from patients with multiple sclerosis (MS) and other neurological diseases. The enzyme activity was found to be elevated in acute cases of MS and reduced during remission. It was present in other demyelinating diseases, and no activity was detected in normal CSF. CNP may be released into CSF from any insult to myelin. The level of activity appears to reflect demyelination and the rate of breakdown of the myelin sheath.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1978

Abnormal T cell subpopulations and circulating immune complexes in the Guillain-Barré syndrome and multiple sclerosis.

Immunologic studies were performed in 21 patients with multiple sclerosis (MS) and 16 with the Guillain-Barré syndrome (GBS). Levels of thymus-derived (T) cells measured by "total" and "active" rosette formation between sheep erythrocytes and peripheral blood mononuclear cells (TEt, TEa) were within normal limits in all the patients, with the exception of four GBS patients, including one who also had received chemotherapy for lymphoma and three who were receiving steroids. When lymphocytes from the 21 patients were incubated with the bone-marrow-derived (B) lymphoblastoid cell line PGLC-33H, there were, for 12 of 18 MS patients and 11 of 16 GBS patients, significant decreases in a subpopulation of peripheral blood T lymphocytes that form "PGLC rosettes" (PGR) with the PGLC-33H cells. (Peripheral blood T cells from normal individuals formed PGR with 23.9 +/- 3.8 percent of PGLC-33H cells.) Using the 125l-C1q binding assay, immune complexes were detected in the serum of 14 of 19 MS patients and 15 of 16 GBS patients. An association between increased C1q binding and decreased PGR values was found in 10 of 18 MS patients and 12 of 17 GBS patients. The results suggest that in both diseases the etiology may involve a decrease in the subset of T cells that bind to the IgM-producing cell line PGLC-33H, in association with the appearance of circulating immune complexes containing the infectious viral agent.

Antigen-Antibody Complex↗
PubMed1977

The differentiation of synthesis from incorporation of basic protein in Quaking mutant mouse myelin.

The incorporation of radioactive label into the myelin basic protein isolated from whole brain and from purified myelin of Quaking mice and normal littermates was compared. four Quaking mice (32 days) and 4 littermate controls were injected intracranially with 150 muCi [2-3H]glycine and 25 muCi of [2-14C]glycine, respectively. One hour later, the 8 mice were sacrificed and their brains combined for common homogenization. The 3H/14C ratios of the small and large basic protiens in whole brain were 3.44 and 2.48 respectively, while the 3H/14C ratios for these proteins in myelin were 0.79 and 1.00, respectively. In the same experiment, the microsomal fraction had a 3H/14C ratio of 2.98 which is the expected ratio for normal incorporation. The results indicate that the synthesis of basic protein in whole brain of Quaking mouse proceeds at a normal rate, but specifically, the incorporation of basic protein into myelin is depressed suggesting a defect at the step of assembly of myelin components into a final membrane product.

Animals↗
PubMed1976

Undernutrition in the developing rat: effect upon myelination.

Long-Evans rats were undernourished from birth by removing the mother from the sucling rats for part of each day; the undernutrition was continued after weaning till 60 days of age by restricting the daily food intake. Brain development was monitored by histologic and selected biochemical analyses coordinated with an ultrastructural morphometric analysis of the pyramidal tract of 30-day-old rats. Brain and body growth were already reduced after 10 days of undernutrition. At 20 days of age, the peak of myelination in the controls, the body and brain weights of the undernourished rats, compared to the controls, were reduced by 25 and 60%, respectively, and by the end of the study (60 days), the brain and body weights were reduced by 30 and 70%, respectively. Morphometric analysis indicated that the proportion of myelinated axons was significantly reduced in starved (34%) relative to control (43%) animals. Fiber analysis revealed that not only were the myelin sheaths thinner in the undernourished rats, but that the sheath was disproportionately reduced relative to the axon diameter. Chemical analysis on a whole brain basis demonstrated a greater than 60% deficit in the relatively myelin-specific galactolipids. (Whole brain analysis included regions more severely affected than the morphometrically analyzed pyramidal tract.) We also obtained evidence for both a delay in the initiation and a general retardation of myelinogenesis. The promyelinating fibers (axons with one or two non-compacted myelin lamellae) still constituted 4.5% of the myelinated fibers in the undernourished animals at 30 days but had declined to 0.3% in the controls. Analysis of the fabtty acids of cerebroside and sulfatide (lipids enriched in myelin) demonstrated in the undernourished group a pattern characteristic of a younger animal. Thus, the effect of undernutrition on the developing rat appears to be one of inhibited and somewhat retarded myelination. These effects were most likely due to a reduction in the number of myelinating glia formed and the restricted capacity of those which form to generate myeline lamellae.

Age Factors↗
PubMed1976

Tay-Sachs disease: a pilot screening program for the detection of the heterozygote in the Charleston Jewish community.

A pilot screening program for the detection of the carrier (heterozygote) of the Tay-Sachs disease (TSD) gene has recently been completed at the Medical University of South Carolina. A fluorometric assay for serum hexosaminidase A and B was performed on the serum of 181 individuals from the Charleston Jewish community. One hundred seventy-six of these individuals were classified as normal based on the percent hexosaminidase A (Hex A) in their serum; five persons were classified as carriers of the Tay-Sachs gene, including a young married couple who were later referred for genetic counseling.

Gene Frequency↗
PubMed1974

Effect of lead intoxication on the postnatal growth of the rat nervous system.

Lead encephalopathy was induced in developing Long-Evans rats by adding lead carbonate (4% w/w) to the diet of nursing mother immediately after delivery. The morphological and biochemical features of cerebral ontogenesis were studied in 30-day-old rats. By the 30th postnatal day, the overall effect of lead intoxication was retardation of brain growth. The mass of both the cerebral gray and white matter was appreciably reduced in the lead rats without any reduction in cell populations. While the neuronal population was preserved, the growth of neurons was reduced and their maturation retarded. The retarded neuronal growth was characterized by the limited proliferation of processes in the neuropil and by the reduction in the number of synapses per neuron. However, synaptogenesis was neither delayed nor perturbed but reduced by the limited development of neuronal dendritic fields. The myelination was altered and its cerebral content significantly reduced. The effect of lead on myelination was one of hypomyelination. The hypomyelination appears to be primarily related to retarded growth and maturation of the neuron and is not a reflection of a defect in the myelinating glia or a delay in the initiation of myelination.

Animals↗