Biomedical subjects
Publications and source records attributed to A Weiner.
Farnesyl pyrophosphate synthetases from pig and avian livers exhibit higher catalytic activities in the presence of 0.2 mM ZnCl2 than in the presence of MgCl2 or MnCl2 which are known to be required for enzyme activity. This is not the case for isopentenyl pyrophosphate isomerase or squalene synthetase.
This study follows up supracondylar fractures of the humerus in 41 children. Twenty-one boys and 20 girls were observed over an average period of 4.6 yr. The ages at the time of the fracture varied between 1 and 15 yr, the highest incidence occurring between 5 and 8 yr. Twenty-four patients were treated by closed reduction and long arm cast fixation, and 17 were handled by closed reduction after overhead skeletal traction. The children who were treated with skeletal traction had comparatively more-severe fractures. Although the results have no statistical significance, a greater range of motion was regained in the elbows treated by the skeletal traction method. Following treatment, none of the patients had complications from infection or from neurovascular problems. One of the problems this study posed was in comparing our work to similar published reports. We therefore developed a new scoring system for evaluating the results achieved in treatment of this type of fracture.
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Nursing assistants (aides) and licensed practical nurses (LPNs) from three proprietary nursing homes participated in a continuing education program designed to enhance knowledge and attitudes about the elderly in long-term care. The program covered six weeks for the initial 115 aides and one full-day seminar for the 83 LPNs. The content covered knowledge and human anatomy, the physiology of normal aging, physical and psychosocial problems of the elderly and, for the nurses, problems associated with cardiovascular accidents. The final participants (29 aides and 52 LPNs) consisted of those who were tested before and after their training with respect to knowledge, life satisfaction, and attitudes toward the elderly. Results indicated overall favorable changes for both aides and LPNs, particularly in the areas of increased knowledge and more positive attitudes. The data suggest that continuing education is an effective means of influencing the knowledge and attitudes of personnel in long-term care facilities, and it should be a first step toward improving the quality of care for elderly residents.
For yeast glyoxalase I, a stereospecific proton-transfer mechanism requires the formation of either a cis or a trans-enediol intermediate. Analogs of the two possible isometric enediol intermediates, formed from the hemimercaptal due to phenylglyoxal and glutathione, have been synthesized in which the oxygen atoms of the enediol are replaced by protons. Both isomeric analogs are strong linear competitive inhibitors of the enzyme having nearly equal inhibition constants: Ki(cis) = 0.10 mM; Ki(trans) = 0.16 mM. This suggests that while hydrophobic interactions between substrate, enediol intermediate and enzyme may contribute significantly to binding, this type of interaction is not an independent stereochemical determinant of the reaction.
Protein requirements for conversion of phiX174 single-stranded DNA to a double-stranded replicative form with a small gap (RF II) have been determined by resolution and reconstitution of the multienzyme system from extracts of gently lysed Escherichia coli. Assays depended on: (a) complementation of extracts of thermosensitive mutants and (b) fractionation of extracts of wild type cells to divide essential components into groups, each of which was further resolved. These procedures have yielded eight proteins: dnaB protein, dnaC protein, proteins i and n (two novel proteins without a defined genetic locus), dnaG protein, DNA polymerase III holoenzyme (polymerase III and copolymerase III), and DNA unwinding protein; purification procedures for the first four are presented here. (Closure of RF 22 requires as with phage M13, DNA polymerase I and ligase.)
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Replication is accomplished by multienzyme systems whose operations are usefully considered in respect to three stages of the process: initiation, elongation, anid termination. 1) Initiation entails synthesis of a short RNA fragment that serves as primer for the elongation step of DNA synthesis. This stage, probed by SS phage DNA templates, reveals three distinctive and highly specific systems in E. coli. The Ml3 DNA utilizes RNA polymerase in a manner that may reflect how plasmid elements are replicated in the cell. The ØX174 DNA does not rely on RNA-polymerase, but requires instead five distinctive proteins which may belong to an apparatus for initiating a host chromosome replication cycle at the origin. The G4 DNA, also independent of RNA polymerase, needs simply the dnaG protein for its distinctive initiation and may thus resemble the system that initiates the replication fragments at the nascent growing fork. In each case it is essential that in vitro the DNA-unwinding protein coat the viral DNA and influence its structure. 2) Elongation is achieved in every case by the multisubunit, holoenzyme form of DNA polymerase III. Copolymerase III, which is an enzyme subunit, and adenosine triphosphate are required to form a proper complex with the primer template but appear dispensable for the ensuing chain growth by DNA polymerase (33). 3) Termination requires excision of the RNA priming fragment, filling of gaps and sealing of interruptions to produce a covalently intact phosphodiester backbone. DNA polymerase I has the capacity for excision and gapfilling and DNA ligase is required for sealing. What once appeared to be a simple DNA polymerase-mediated conversion of a single-strand to a duplex circle (34) is now seen as a complex series of events in which diverse multienzyme systems function. Annoyance with the difficulties in resolving and reconstituting these systems is tempered by the conviction that these are the very systems used ,by the cell in replicating its chromosome and extrachromosomal elements. Thus, understanding of the regulation of replication events in the cell, their localization at membrane surfaces and integration with cell division, and their coordination with phage DNA maturation and particle assembly will all be advanced by knowledge of the components of the replicative machinery.
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The Matrix model was originally developed in response to the cocaine epidemic of the 1980s. The program consists of relapse prevention groups, education groups, social support groups, individual counseling, and urine and breath testing delivered in a structured manner over a 16-week period. The treatment is a directive, nonconfrontational approach which focuses on current issues and behavior change. Several evaluations of the model have supported its usefulness and efficacy with methamphetamine (MA) users. Methamphetamine users appear to respond to treatment similarly to cocaine users and many continue to show improvements at follow-up.