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Biomedical subjects

J C Sipe

Publications and source records attributed to J C Sipe.

14 recordsLinked to original sources
PubMed1992

P300 in multiple sclerosis: a preliminary report.

The P300 component of the event-related brain potential (ERP) elicited with auditory stimuli and pattern-shift visual evoked potentials (VEPs) was obtained from 16 patients with multiple sclerosis (MS) and 16 matched control subjects. P300 latency was significantly longer and component amplitude relatively depressed in the MS patients compared to control subjects. The P100 potential of the VEP also was delayed for both full-field and half-field stimulus conditions in the patients compared to control subjects. The findings suggest that the P300 ERP may reflect the cognitive decline associated with MS.

Adult↗
PubMed1985

Immunological complications in multiple sclerosis patients receiving interferon.

In a prospective, placebo-controlled study designed to test the efficacy of human alpha interferon (IFN) in the treatment of multiple sclerosis, we monitored several immunological functions. Interferon was shown to have many effects on the immune system, including activation of natural killer cells in vivo and elevation of serum immunoglobulin and cerebrospinal fluid IgG ratios. Furthermore, all patients who received IFN developed antibody titers to a protein contaminant (molecular weight, 27 kilodaltons) in the IFN preparation. This antibody was associated with an elevation in serum concentrations of C1q- and Raji-binding immune complexes in 6 of 12 patients. Some of these 12 patients developed symptoms suggestive of immune complex disease. IFN had pronounced effects on the immune system of these patients.

Antibodies↗
PubMed1979

Ultrastructure of skin biopsy specimens in lysosomal storage diseases: common sources of error in diagnosis.

Common sources of error in the diagnosis of lysosomal storage diseases by ultrastructural examination of skin specimens have been identified in a series of biopsies from 72 patients. Four principal factors have emerged as leading pitfalls and sources of error in diagnosis. First, the skin biopsy technique itself may lead to alterations of normal skin ultrastructure. Second, artifacts may be produced during fixation and preparation of tissue for electron microscopy. Third, cellular organelles and structures normally present in human skin may be mistakenly interpreted as pathological. Fourth, the use of cultured skin fibroblasts for ultrastructural identification of storage material is often accompanied by artifacts induced in tissue culture and is not recommended. Recognition of these common problems may aid interpretation of the fine structure of skin abnormalities. Furthermore, when skin biopsy specimens are used as the primary source of diagnostic material, correlation of both skin ultrastructure and assay for specific lysosomal enzymes in cultured dermal fibroblasts will facilitate diagnostic accuracy.

Biopsy↗
PubMed1978

The islands of Calleja: organization and connections.

The islands of Calleja (IC) in the rate are composed of seven small groups of granule cells in the polymorph layer of the olfactory tubercle and one large group, the insula magna, which lies along the border between septum, nucleus accumbens and nucleus of the diagonal band. The cytoarchitecture and neuronal morphology of the IC and surrounding cells, studied using Nissl-stained and Golgi-Kopsch material, are described. In addition, the afferent and efferent connections of the IC were analyzed using fluorescence histochemistry, the autoradiographic tracing method, and the anterograde and retrograde horseradish peroxidase methods. Topographically organized projections to the IC from the dopamine-containing cells of the substantia nigra-ventral tegmental area are demonstrated by the glyoxylic acid fluorescence histochemical method and the autoradiographic tracing technique. Anterograde and retrograde horseradish peroxidase studies provide evidence for reciprocal, topographically organized interconnections between the IC and the septum, nucleus accumbens, amygdala and piriform cortex. These observations indicate that the IC constitute a unique population of granule cells, located in the olfactory tubercle, innervated by dopamine neurons of the mesencephalon and interconnected with olfactory and non-olfactory components of the basal forebrain.

Animals↗
PubMed1977

The lateral hypothalamic area. An ultrastructural analysis.

An ultrastructural analysis of the rat lateral hypothalamic area (LHA) was undertaken in order to provide an initial step in the characterization of this complex area which appears to participate in a number of important neural functions. The organization of the normal tuberal LHA was compared to the area following acute and chronic denervating lesions. In the normal animal, the principal features of the LHA are the presence of lateral hypothalamic neurons, a major sagittal pathway (the medial forebrain bundle, MFB) and the interposed neuropil richly populated by a variety of synaptic terminal types. Alterations in the synaptic organization of the LHA following rostral and caudal MFB lesions were most pronounced in animals with acute and chronic caudal lesions. A 10% reduction of synaptic terminals containing 800-1000 A diameter dense core vesicles and a 10% increase in terminals containing lucent core vesicles was observed in animals with caudal lesions while no significant redistribution of synaptic terminal types occurred with rostral lesions. The preliminary degeneration experiments indicate that identification of the numerous and diverse afferents to the LHA neuropil may be aided by this method but that a detailed and systematic ultrastructural analysis will be required to identify sources of input with certainty.

Animals↗
PubMed1976

Gap junctions between astrocytes during growth and differentiation in organ culture systems.

Fetal rat neocortex maintained in organ culture systems with the use of sponge foam matrices and millipore filter platforms undergoes growth and cytodifferentiation along classical neuronal and glial lines up to 36 days in vitro (DIV). Astrocytic differentiation is characterized by accumulation of 80-90 A glial filaments in the cell bodies and processes of astrocytes. Gap or nexus junctions closely resembling those formed in mammalian brain in situ are identified by 15 DIV. By 36 DIV, interastrocytic gap junctions are numerous and frequently join extensive lengths of adjacent glial plasma membranes. The results suggest that these organ culture systems may provide a favorable environment for the study of cellular structure and function of coupled neuroglia.

Animals↗
PubMed1976

Gap junctions between human meningioma cells maintained in organ culture.

Intercellular junctions were commonly observed in a human syncitial meningioma maintained in organ culture for up to 44 days in vitro (DIV) using gelatin sponge foam matrices. The junctions were identified as one of three types: desmosomes; tight junctions; or gap junctions. Of the three types, gap junctions were frequently encountered and showed preservation of their characteristic ladder-like substructure. The results suggest that organ culture provides an environment that may facilitate correlation of the structure and function of gap junctions between coupled human meningioma cells.

Brain Neoplasms↗
PubMed1976

Astrocytic gap junctions in the rat lateral hypothalamic area.

An extensive system of gap or nexus junctions has been found between astrocytic processes in the neuropil of the lateral hypothalamic area in the albino rat. These specialized interastrocytic junctions occur in regions of high synaptic density where neural processes are separated by the interconnected glial system. In this study, 90% of the gap junctions observed in the lateral hypothalamic neuropil are in the immediate proximity of synaptic terminals. The close morphological relationship of these glial gap junctions with synaptic contacts suggests that they may play a significant role in the process of synaptic transmission.

Animals↗
PubMed1976

Transmissible mink encephalopathy. Reduced spongiform degeneration in aged mink of the Chediak-Higashi genotype.

Mink which are 18 months or older and are dying of transmissible mink encephalopathy (TME) have been found to have a marked reduction in spongiform degeneration of the brain if they are homozygous for the Aleutian gene and thus exhibit the autosomal recessive disorder known as the Chediak Higashi (CH) syndrome. CH mink younger than 1 year, and young or old non-CH mink have a typical lesion profile with widespread microvacuolation of the neuropile. Whereas aged CH mink have reduced spongiform degeneration at both the light and electron microscopic level, there is no other apparent alteration in the TME disease process. The length of incubation, clinical signs, astrocytic response, and brain concentration of the TME agent are comparable to those seen in non-CH mink. We conclude that spongiform degeneration is a secondary change in TME and speculate that vacuolation may be the result of lysosomal enzymes causing an increase in ganglioside catabolism.

Age Factors↗
PubMed1975

An experimental mouse testicular teratoma as a model for neuroepithelial neoplasia and differentiation. II. Electron microscopy.

The electron microscopic features of the stages of divergent neuroepithelial differentiation in the solid implants of a transplantable mouse testicular teratoma (OTT-6050) are presented and compared to the sequential stages of cytogenesis that have been described in the developing avian and mammalian central nervous system. Primitive neuroepithelial tumor cells showed the features of undifferentiated multipotential matrix (or ventricular) cells of the neural tube. They formed primitive medullary rosettes, from which various transitions were traced to more differentiated, cilia-containing ependymoblastomatous rosettes; the transitional features included increased granular endoplasmic reticulum and microvilli formation. Glial differentiation was characterized by the presence of mature ependymal rosettes and of astrocytes containing glial filaments. Neuronal differentiation included the development of synapses and the presence of dense-core vesicles in nerve cell processes. No intermediate cell forms were found that suggested multiple lines of differentiation occurring within a single cell.

Animals↗