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Biomedical subjects

G Ruben

Publications and source records attributed to G Ruben.

5 recordsLinked to original sources

Meningiomas in elderly patients. Clinico-therapeutic considerations.

This study examines the immediate and long-term results of surgical treatment for intracranial meningioma in patients aged 65 and over. Average patient age was 69 years. The most frequent localizations were the convexity (29.8%) and the sphenoid wing (20.1%). Preoperative risk factors included hypertension (16.1%), cardiopathies (16.1%), diabetes (12.9%) pneumopathies (12.9%) and peripheral vascular diseases (9.6%). All patients were assessed according to the Karnofsky Performance Status (KPS). Operative mortality was 18.5% (23 cases). At long term follow up (minimum 4 months, maximum 12 years, average 5 years) 31.5% of patients were cured, 32.3% had improved and 4% had worsened. The risk factors that mainly influenced results included poor preoperative clinical condition as expressed by low KPS, while the most frequent medical postoperative complications that increased the rate of operative mortality were brain edema, infections and lung embolism.

Aged↗

Collective bargaining in 1989: old problems, new issues.

Some problems which plagued negotiators throughout the decade continue into the next, and are joined by additional issues such as rising cost of health insurance, family care, and health and safety concerns.

Collective Bargaining↗

Relaxed circular SV40 DNA as cleavage intermediate of two restriction endonucleases.

We have determined the mode of cleavage of superhelical SV40 DNA (Form I) by restriction endonucleases EcoRI and HpaII at 37 degrees C. By analysis with agarose gel electrophoresis and direct examination with dark field electron microscopy, we found that a large amount of the single-nicked circular DNA (Form II) was produced before the linear SV40 DNA (Form III) appeared. Thus, both restriction enzymes cleave only one strand of the superhelical DNA first. The second cleavage on the complementary strand occurred after a lag period. The first order rate constant for the second cleavage by EcoRI endonuclease was determined and a kinetic reaction scheme for both enzymes is proposed.

DNA Restriction Enzymes↗

Synchronous digestion of SV40 DNA by exonuclease III.

We have established an optimal condition for the synchronous digestion of SV40 DNA with Escherichia coli exonuclease III. Electron microscopy and polyacrylamide gel electrophoresis were used to obtain accurate measurements on the lengths of DNA before and after exonuclease III digestion. Based on this finding, a new method for determining the sequence of long duplex DNA can be realized. It involves (a) the synchronous digestion of the DNA from the 3' ends with exonuclease III, followed by (b) repair synthesis with labeled nucleotides and DNA polymerase, and (c) sequence analysis of the repaired DNA.

Base Sequence↗