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Biomedical subjects

J B FINEAN

Publications and source records attributed to J B FINEAN.

At least 19 recordsLinked to original sources
PubMed1965

ULTRASTRUCTURAL STUDIES OF HUMAN CUTANEOUS NERVE WITH SPECIAL REFERENCE TO LAMELLATED CELL INCLUSIONS AND VACUOLE-CONTAINING CELLS.

One hundred and twenty-nine specimens of human cutaneous nerve obtained from patients suffering from a variety of neuromuscular disorders have been surveyed in detail by electron microscopy. The most striking finding was the presence of lamellated Schwann cell inclusions and of cells containing vacuoles, both of which appear to be derived from myelin and to show some correlation with sensory loss.

Cytoplasm↗
PubMed1962

Electron microscope studies of the structure of the microvilli on principal epithelial cells of rat jejunum after treatment in hypo- and hypertonic saline.

Immersion of the intestinal tissue, from rat jejunum, in hypertonic saline produced very rapid changes in all regions of the epithelial cells, but the apical region was apparently unaffected by hypotonic solutions for at least (1/2) hour. In both cases, blistering of the microvilli was taken as the first sign of degenerative changes which finally resulted in a breakdown to large vesicular particles. Consideration of both normal and modified tissue indicates that the core of the microvillus contains either paired strands or tubular structures. Lateral cross-fibres extended from the core to the microvillus membrane and may be an essential part of the supporting structure of the microvillus. Densitometer traces across the microvillus membrane at various stages of modification indicated that this membrane might include a 75 A unit membrane structure with additional components associated at either surface. Interruptions in the membrane were apparently expanded by the hypotonic solutions and these might possibly be distinguished from preparative artefacts.

Animals↗
PubMed1961

The application of x-ray diffraction and electron microscopy to the study of human peripheral nerve obtained by biopsy.

Human peripheral nerves obtained by biopsy from patients suffering from neuromuscular disorders have been studied by x-ray diffraction and electron microscopy. Few abnormal diffraction patterns have yet been recorded and their significance is not yet established. Electron micrographs have revealed wide variations in the numbers of myelinated fibres included in the nerve trunks and have facilitated a detailed study of the Schwann cell-axon relationships in the large numbers of unmyelinated fibres always present. Some indications of demyelination have been encountered.

Axons↗
PubMed1960

Electron microscope and x-ray diffraction studies of the effects of dehydrations on the structure of nerve myelin. I. Peripheral nerve.

The dehydration of frog sciatic nerve has been studied by allowing specimens to become partially or fully dried before fixation and preparation for electron microscopy. Low magnification electron micrographs of OsO(4)-fixed preparations showed marked tissue shrinkage which could be correlated quantitatively with the loss of water during the preliminary drying. KMnO(4)-fixation appeared to cause a rehydration of the dried tissue. Higher magnification electron micrographs of the OsO(4)-fixed preparations showed a sequence of modifications of the myelin layers which could be correlated with changes in the small-angle x-ray diffraction data which were recorded during drying. An intermediate stage of drying was characterised by a partial collapse of layers and a disappearance of the intraperiod dense line in some regions of the myelin sheath. Continuity between collapsed and non-collapsed layers was maintained throughout the sheath. The fully dried preparation showed two main modifications of the myelin layers. In many regions the layers (principal layers) resembled those of normal preparations, but showed an intensification and frequently a doubling of the intraperiod dense line. In addition, there was a very extensive system of fine (40 A periodicity) dense layers, some of which could be demonstrated to be continuous with the principal layers. In such cases it was observed that two of the fine layers were related to each principal layer. The correlation between diffraction data and electron microscope data is discussed, and some speculations are made concerning the molecular significance of the observations.

Animals↗
PubMed1960

Electron microscope and x-ray diffraction studies of the effects of dehydration on the structure of nerve myelin. II. Optic nerve.

The dehydration of rat optic nerve has been studied by allowing specimens to become partially or fully dried before fixation and preparation for electron microscopy. A correlation is established between electron micrographs of the myelin sheath and corresponding small-angle x-ray diffraction patterns. The modifications of the optic nerve myelin layers during drying were very similar to those described in more detail for the myelin of frog sciatic nerve. The most striking difference was that the system of fine layers characteristic of the fully dried myelin was much more extensive in the case of the optic nerve, and the layer thickness was significantly greater than the corresponding layer in the frog sciatic nerve preparation. The significance of these correlations is discussed.

Animals↗