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R K Liem

Publications and source records attributed to R K Liem.

105 records · Page 6Linked to original sources
PubMed1979

Biochemical and immunological characterization of neurofilaments in experimental neurofibrillary degeneration induced by aluminum.

In order to identify the protein composition of 10 nm neuronal filaments, we prepared enriched fractions of rabbit spinal neurons undergoing experimental neurofilamentous degeneration induced by aluminum. Electron microscopy of the isolated perikarya showed well-preserved, large perinuclear masses of neurofilaments, which were not found in similarly isolated control perikarya. Comparison of these glial-free fractions by SDS-polyacrylamide gel electrophoresis revealed several-fold augmentation in the filament-enriched neurons of proteins migrating at 68,000 and 160,000 daltons, with an additional component at 200,000 daltons. Otherwise, the protein patterns were identical; no band was found at 51,000 daltons, the molecular weight assigned to the major proteins both of glial filaments and of a previously reported bovine brain filament preparation. An antiserum raised against the 160,000 dalton component of a modified bovine brain filament fraction produced specific and intense fluorescent staining of the aluminum-induced neurofilament bundles. Antibodies to the 51,000 dalton protein of brain filaments and to tubulin failed to stain the induced filaments. The results strongly support the hypothesis that both normal and aluminum-induced neuronal filaments are composed of 68,000, 160,000 and 200,000 dalton polypeptides and do not contain significant amounts of the 51,000 dalton filament protein. The likelihood of biochemical heterogeneity among organelles with similar morphology, namely the glial and neuronal filaments, is raised.

Aluminum↗
PubMed1979

Neurofilaments.

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Actins↗
PubMed1978

Intermediate filaments in nervous tissues.

Intermediate filaments have been isolated from rabbit intradural spinal nerve roots by the axonal flotation method. This method was modified to avoid exposure of axons to low ionic strength medium. The purified filaments are morphologically 75-80 percent pure. The gel electrophoretogram shows four major bands migrating at 200,000, 145,000, 68,000, and 60,000 daltons, respectively. A similar preparation from rabbit brain shows four major polypeptides with mol wt of 200,000 145,000, 68,000, and 51,000 daltons. These results indicate that the neurofilament is composed of a triplet of polypepetides with mol wt of 200,000, 145,000, and 68,000 daltons. The 51,000-dalton band that appears in brain filament preparations as the major polypeptide seems to be of glial origin. The significance of the 60,000- dalton band in the nerve root filament preparation is unclear at this time. Antibodies raised against two of the triplet proteins isolated from calf brain localize by immunofluorescence to neurons in central and peripheral nerve. On the other hand, an antibody to the 51,000-dalton polypeptide gives only glial staining in the brain, and very weak peripheral nerve staining. Prolonged exposure of axons to low ionic strength medium solubilizes almost all of the triplet polypeptides, leaving behind only the 51,000- dalton component. This would indicate that the neurofilament is soluble at low ionic strength, whereas the glial filament is not. These results indicate that neurofilaments and glial filaments are composed of different polypeptides and have different solubility characteristics.

Animals↗
PubMed1975

One hundred consecutive operations for diverticulitis of the colon.

This report describes 100 consecutive patients treated surgically for diverticulitis of the colon. The main indications for operation were recurrent attacks (33), rapid progressive symptoms (17), bleeding (16), palpable mass (14), or combinations of the above. Eighty-four patients had primary resection (two deaths), ten had staged procedure (two deaths), and six had Hartmann procedures (one death). The mortality was highest in staged procedures as this group of patients included those with complications resulting in the greatest operative risks. No deaths occurred in the elective cases. In 25 cases, various complications developed. The most common was wound infection and sepsis. The five deaths in the series are reported in detail with an evaluation of possible alternative methods of treatment. Follow-up of the series showed only one recurrence in the two years after operation.

Adult↗