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Biomedical subjects

M Dewey

Publications and source records attributed to M Dewey.

60 records · Page 4Linked to original sources
PubMed1976

Altered properties of deoxyribonucleic acid polymerase I isolated from the membrane of bacteriophage T4-infected Escherichia coli.

Previous studies have shown that a large fraction of the host cell deoxyribonucleic acid (DNA) polymerase I (EC 2.7.7.7) becomes associated with the cell membrane shortly after infection with bacteriophages T4 and T7. The present investigation of the bound enzyme revealed that the polymerase activity can be eluted from the membrane with chelating agents, and that the material thus obtained shows many properties that distinguish it from purified DNA polymerase I. These include its chromatographic behavior, sedimentation rate, sensitivity to anti-DNA polymerase I antiserum, and activity with synthetic and natural DNA primers. Several of these physical and biological parameters were shown to revert slowly during storage to those exhibited by the purified enzyme. Efforts to determine whether the unusual properties of the membrane enzyme resulted from its association with DNA failed to support that possibility. These observations suggest that either the cause or the result of membrane binding of DNA polymerase I is a transient change in conformation or structure of the enzyme, with a resultant change in its enzymatic activity.

Cell Membrane↗
PubMedDate not supplied

Outcomes of add-on treatment with lamotrigine in partial epilepsy.

The need for new antiepileptic drugs (AEDs) and more sensitive methods of assessing their efficacy is well recognized. This study was designed to evaluate the efficacy and safety of lamotrigine (LTG), a potential new AED and to develop and test new outcome measures. A health-related quality of life (HRQL) model was developed which contains previously validated measures of anxiety, depression, happiness, overall mood, self-esteem, and mastery and a specifically designed seizure severity scale with patient- and caregiver-based components. This HRQL model was used in a randomized, placebo-controlled, double-blind, cross-over study of LTG in 81 patients with refractory partial seizures. Seizure frequency was the primary measure and seizure severity and the HRQL were secondary measures of efficacy. The reduction in seizure frequency with LTG, relative to placebo, was 29.7% [95% confidence interval (CI) 17.8%, 39.9%] for total seizure count, 33.4% (95% CI 14.8%, 47.9%) for complex partial seizures (CPS) and 20.3% (95% CI 0.3%, 36.2%) for secondarily generalized tonic-clonic seizures (GTCS). However, although 41 patients elected to continue with LTG, only 11 experienced at least 50% reduction in total seizures, indicating that other factors influenced their decision. The score with LTG, relative to placebo, was significantly lower for the ictal (p = 0.017) and caregivers (p = 0.035) subscales of the seizure severity scale and significantly higher for happiness (p = 0.003) and mastery (p = 0.003). Simple correlation and multiple-regression analyses indicate that the effects on seizure frequency, seizure severity, and psychological variables appear to be independent of each other. This study indicates that LTG is effective in reducing seizure frequency and has additional favorable effects on seizure severity, mood, and perceived internal control. Some of the scales used indicate the potential of secondary measures of efficacy to enhance the sensitivity of trials of new AEDs.

Adolescent↗
PubMedDate not supplied

The Katz Adjustment Scale: modification for use with victims of traumatic brain and spinal injury.

Although the assessment of the social, emotional and personality sequelae of traumatic injury is of central clinical and medico-legal importance, no satisfactory standard assessment device for this purpose has yet been developed. A multicentered study of a mixed group of head and spinally injured patients is reported. Factor analysis of a modified version of the relatives' form of the Katz Social Adjustment Scale (KAS-R) yielded 30 first-order factors under three main domains of emotional/psychosocial, physical/intellectual and psychiatric changes, together with seven second-order factors which were readily identifiable in terms of syndromes accompanying traumatic injury. Discriminant function analyses indicated that prediction of patient group using KAS-R data was most accurate using the current study's first-order factors as compared with the original factor structure proposed by Katz and Lyerly or the second-order factors from the current analyses. The modified KAS-R shows considerable promise as an instrument for measuring the complex social, emotional and personality changes following traumatic injury, with special significance for assessing brain-injury victims. The representativeness of the current patient sample and implications for future development of the method are discussed.

Activities of Daily Living↗