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Biomedical subjects

M C Fishman

Publications and source records attributed to M C Fishman.

At least 145 records · Page 8Linked to original sources
PubMed1986

Nuclear magnetic resonance imaging in evaluation and follow-up of children treated for coarctation of the aorta.

Electrocardiographic-gated nuclear magnetic resonance imaging was used to evaluate 10 patients, aged 2.5 to 18 years, with coarctation of the aorta. Six patients had balloon dilation angioplasty, one had surgical repair and three are awaiting treatment. Imaging studies were performed before and after therapy in three patients. In all pretreatment studies, the sagittal and 60 degrees left anterior oblique imaging planes adequately revealed the anatomy of the coarctation. Post-treatment imaging studies demonstrated effective relief of the coarctation in all cases. In three of the six patients who had balloon angioplasty, there was a variable degree of dilation of the aorta at the site of the previous coarctation. Nuclear magnetic resonance imaging is an effective noninvasive imaging method for visualizing coarctation of the aorta and for follow-up after treatment.

Adolescent↗
PubMed1986

Vascular magnetic resonance imaging.

Natural contrast from flow void potentiates the diagnosis of the intimal flap of aortic dissection, the dilated contour of aortic aneurysm, the protruding plaque of atherosclerotic disease, the recognition of deep vein thrombosis, and the identification of a number of acquired and congenital vascular abnormalities. Although MRI is costly at the present, the advantages of vascular MRI include noninvasive multiplanar imaging, no ionizing radiation, no contrast material requirements, and its use as an alternative to technically limited ultrasonography or computed tomography. MRI can define anatomy, measure blood flow, and be used for serial examinations in following disease processes and response to treatment. Future research with tissue characterization of atherosclerotic plaque may allow for early diagnosis and treatment of this ubiquitous disease. Not only chemical but also metabolic studies, including tissue perfusion in the heart and other solid viscera, would be of great value. Undoubtedly, MRI will have a permanent role in cardiovascular diagnosis.

Arteries↗
PubMed1985

Neuronal traits of clonal cell lines derived by fusion of dorsal root ganglia neurons with neuroblastoma cells.

In an attempt to immortalize the gene products of single neurons, somatic cell hybrids were produced by fusion of embryonic rat dorsal root ganglion (DRG) neurons with mouse neuroblastoma cells. Embryonic day 13 rat DRGs were fused with mouse neuroblastoma cells deficient in hypoxanthine phosphoribosyltransferase (HPRT; IMP:pyrophosphate phosphoribosyltransferase, EC 2.4.2.8). The hybrid cells were selected in medium with 100 microM hypoxanthine/1 microM aminopterin/12 microM thymidine to eliminate the neuroblastoma cells and with cis-hydroxyproline to retard fibroblast growth. Of the 17 lines derived, 4 manifested neuronal properties and were cloned. These lines retain both rat and mouse chromosomes and synthesize characteristic rat and mouse isoenzymes. Neuronal gangliosides, action potentials, and extensive neurite-like processes are exhibited by these hybrid cells, properties characteristic of DRG neurons but not of the neuroblastoma parent. Each line manifests a unique combination of action-potential properties and cell-surface markers, suggesting the selective expression of subsets of DRG neuronal genes. All of these neuronal properties are expressed constitutively, without the need for chemical induction or mitotic inhibition, and stably, without diminution after at least 5 months in culture. These lines may prove useful in the identification and isolation of gene products that characterize individual or small subsets of DRG neurons.

Animals↗
PubMed1985

Oxygen chemoreception by carotid body cells in culture.

Chemoreceptors for oxygen reside within the carotid body, but it is not known which cells actually sense hypoxia and by what mechanisms they transduce this information into afferent signals in the carotid sinus nerve. We have developed systems for the growth of glomus cells of the carotid body in dissociated cell culture. Here we demonstrate that, as in vivo, these cells contain the putative neurotransmitters dopamine, serotonin, and norepinephrine. Oxygen tension regulates the rate of dopamine secretion from the glomus cells. Similar to chemically stimulated catecholamine secretion from other adrenergic cells this hypoxia-stimulated release requires extracellular calcium. These results are compatible with the suggestion that the glomus cells of the carotid body are chemoreceptor cells and that they signal hypoxia by regulated secretion of dopamine.

Adrenal Medulla↗
PubMed1984

Synapse repression in cell culture.

The phenomenon of synapse repression was investigated in cell culture. It was found that the number of synapses between ciliary ganglion neurons and myotubes was reduced by the concomitant presence of ventral spinal cord neurons. Neurons from dorsal root ganglia, dorsal spinal cord or cortex did not cause a reduction. Conditioned medium from ventral spinal cord-myotube co-cultures was without effect suggesting the absence of soluble 'repression factors'. The addition of D-tubocurarine partially reversed the repression, indicating that the phenomenon has both activity-dependent and activity-independent aspects.

Animals↗
PubMed1984

A few axonal proteins distinguish ventral spinal cord neurons from dorsal root ganglion neurons.

A series of proteins putatively involved in the generation of axonal diversity was identified. Neurons from ventral spinal cord and dorsal root ganglia were grown in a compartmented cell-culture system which offers separate access to cell somas and axons. The proteins synthesized in the neuronal cell somas and subsequently transported into the axons were selectively analyzed by 2-dimensional gel electrophoresis. The patterns of axonal proteins were substantially less complex than those derived from the proteins of neuronal cell bodies. The structural and functional similarity of axons from different neurons was reflected in a high degree of similarity of the gel pattern of the axonal proteins from sensory ganglia and spinal cord neurons. Each axonal type, however, had several proteins that were markedly less abundant or absent in the other. These neuron-population enriched proteins may be involved in the implementation of neuronal diversity. One of the proteins enriched in dorsal root ganglia axons had previously been found to be expressed with decreased abundance when dorsal root ganglia axons were co-cultured with ventral spinal cord cells under conditions in which synapse formation occurs (P. Sonderegger, M. C. Fishman, M. Bokoum, H. C. Bauer, and P.G. Nelson, 1983, Science [Wash. DC], 221:1294-1297). This protein may be a candidate for a role in growth cone functions, specific for neuronal subsets, such as pathfinding and selective axon fasciculation or the initiation of specific synapses. The methodology presented is thus capable of demonstrating patterns of protein synthesis that distinguish different neuronal subsets. The accessibility of these proteins for structural and functional studies may contribute to the elucidation of neuron-specific functions at the molecular level.

Animals↗
PubMed1984

Carotid body cell culture and selective growth of glomus cells.

Cells of the fetal carotid body have been obtained by enzymatic digestion and maintained in culture both as single cells and as clusters for up to 2 mo. The glomus cells in culture synthesize catecholamines and adenine nucleotides, as determined by histochemical methods, and contain characteristic dense-core vesicles. Their growth requirements are different from other cells of neural crest origin in that they do not depend on nerve growth factor (as do sympathetic neurons) or corticosteroids (as do SIF cells) for survival. Neither hypoxia nor hypercarbia affects survival or relative preponderance of glomus cells in culture. Tyrosine-free medium, which selects for cells containing tyrosine hydroxylase, eliminates most of the nonadrenergic cells, thereby providing a culture dramatically enhanced in glomus cells.

Animals↗
PubMed1984

Radiographic manifestations of spontaneous renal sinus hemorrhage.

The radiographic and computed tomographic features of nontraumatic (spontaneous) hemorrhage into the renal sinus in four patients on anticoagulant therapy are described. Spontaneous renal sinus hemorrhage, a benign self-limited process related to anticoagulation, may have a lesser association with occult renal neoplasms than other types of renal bleeding. The diagnostic criterion of uncomplicated bleeding into the renal sinus is extrinsic compression of the pyelocaliceal system that proves to be completely reversible with spontaneous dissolution of clot. Often there is impaired excretion of contrast material with proximal caliectasis.

Aged↗
PubMed1984

The dissection sign of nonreducible ileocolic intussusception.

A retrospective study of 90 cases of ileocolic intussusception seen over a 5-year period was undertaken to identify features of failed hydrostatic reductions. A new, reliable sign of nonreducible intussusception was found: the dissection sign. Of the 90 cases, 23 demonstrated barium dissecting between the intussusceptum and intussuscipiens ; of those, nine had necrotic bowel found at surgery. All of the 23 cases with dissection failed hydrostatic reduction. Of the 23 patients, 22 were below age 2 years. None of those reduced by barium enema had dissection. The dissection sign on barium enema for ileocolic intussusception is an indication to discontinue hydrostatic reduction and to institute surgical treatment, especially in patients under age 2 years.

Barium Sulfate↗
PubMed1983

Axonal proteins of presynaptic neurons during synaptogenesis.

Changes occur in the synthesis and axonal transport of neuronal proteins in dorsal-root ganglia axons as a result of contact with cells from the spinal cord during synapse formation. Dorsal-root ganglia cells were cultured in a compartmental cel culture system that allows separate access to neuronal cell bodies and their axons. When cells from the ventral spinal cord were cultured with the dorsal-root ganglia axons, synapses were established within a few days. Metabolic labeling and two-dimensional electrophoresis revealed that four of more than 300 axonal proteins had changed in their expression by the time synapses were established. The highly selective nature of these changes suggests that the proteins involved may be important in the processes of axon growth and synapse formation and their regulation by the regional environment.

Animals↗
PubMed1983

High protein content: another cause of CT hyperdense benign renal cyst.

A high density renal mass (35 Hounsfield units), which did not enhance after intravenous contrast material proved to be a renal cyst containing a very proteinaceous fluid. The high protein concentration was the apparent cause of the unusually high attenuation values observed. This case is discussed and the causes of hyperdense benign renal cysts on computed tomography are reviewed.

Aged↗
PubMed1981

Renin and angiotensin: the complete system within the neuroblastoma x glioma cell.

Cells of the homogeneous hybrid line neuroblastoma x glioma (NG108-15) have many neuronal properties. Immunocytochemical tests show that they contain both immunoreactive renin and angiotensin; direct radioimmunoassays show that they are positive for renin, angiotensin I, and angiotensin II; enzymatic assays show that they contain angiotensinogen and converting enzyme as well. The renin appears to be present in an enzymatically inactive form that can be activated by trypsin and then blocked by antiserum to purified mouse submaxillary renin. Renin concentration and activity are increased by enhancing cellular differentiation with dibutyryl cyclic adenosine monophosphate or by serum withdrawal. These findings demonstrate a complete renin-angiotensin system within these neuron-like cells, and suggest that activation of intracellular renin could generate angiotensin II.

Angiotensin I↗