PubMed Health⌕ Search

Biomedical subjects

M J Moore

Publications and source records attributed to M J Moore.

16 recordsLinked to original sources
PubMed1992

C-terminal cysteines of Tn501 mercuric ion reductase.

Mercuric ion reductase (MerA) catalyzes the reduction of Hg(II) to Hg(0) as the last step in the bacterial mercury detoxification pathway. A member of the flavin disulfide oxidoreductase family, MerA contains an FAD prosthetic group and redox-active disulfide in its active site. However, the presence of these two moieties is not sufficient for catalytic Hg(II) reduction, as other enzyme family members are potently inhibited by mercurials. We have previously identified a second pair of active site cysteines (Cys558 Cys559 in the Tn501 enzyme) unique to MerA, that are essential for high levels of mercuric ion reductase activity [Moore, M. J., & Walsh, C. T. (1989) Biochemistry 28, 1183; Miller, S. M., et al. (1989) Biochemistry 28, 1194]. In this paper, we have examined the individual roles of Cys558 and Cys559 by site-directed mutagenesis of each to alanine. Phenotypic analysis indicates that both merA mutations result in a total disruption of the Hg(II) detoxification pathway in vivo, while characterization of the purified mutant enzymes in vitro shows each to have differential effects on catalytic function. Compared to wild-type enzyme, the C558A mutant shows a 20-fold reduction in kcat and a 10-fold increase in Km, for an overall decrease in catalytic efficiency of 200-fold in kcat/Km. In contrast, mutation of Cys559 to alanine results in less than a 2-fold reduction in kcat and an increase in Km of only 4-5 fold for an overall decrease in catalytic efficiency of only ca. 10-fold in vitro. From these results, it appears that Cys558 plays a more important role in forming the reducible complex with Hg(II), while both Cys558 and Cys559 seem to be involved in efficient scavenging (i.e., tight binding) of Hg(II).

Alanine↗
PubMed1978

Bilateral primary germ cell testicular tumors: report of four cases and review of the literature.

Bilateral primary germ cell tumors of the testicle are rare. The last comprehensive review of the literature (1955) revealed a 1.6% incidence. However, during the past twenty years, cases have been reported more often, raising the questions of increased frequency due to prolonged survival following surgery and/or roentgen therapy for unilateral tumors. A search of the medical journals during the past two decades fails to show any increased frequency of bilaterality (1.56%). All general combinations of cell types may occur and the tumors may appear simultaneously or sequentially. Successive seminomas are seen more often followed in frequency by concurrent seminomas. Although 50% of the second primaries were diagnosed within five years, 3% of the patients developed the second tumor after 20 years, stressing the need for extended follow-up. Factors affecting the diagnosis, management and prognosis of bilateral testicular tumors are discussed. Four additional cases of bilateral germ cell tumors are described.

Adult↗
PubMed1977

Eye contact and face scanning in early infancy.

Visual fixations of 3- to 5-week-old, 7-week-old, and 9- to 11-week-old infants were recorded as they scanned an adult's face which was stationary, moving, or talking. A dramatic increase in face fixations occurred between 5 and 7 weeks for all conditions. Talking produced an intensification of scanning in the eye area in the two older groups.

Aging↗
PubMed1977

New evidence on the value of birth expectations.

Past national surveys regarding birth expectations have usually been restricted to currently married women, a fact which has led demographers to question the usefulness of these data. Because the June 1976 Current Population Survey includes the expectations of all women in a cohort regardless of marital status, it provides the data needed to evaluate biases due to restricted survey universes. At older ages, where there are substantial differences in lifetime expectations between currently married and single women, there are relatively few single women; at younger ages, however, where the proportion of single women in a cohort is relatively large, the differences in expectations are small. This counterbalancing effect makes the lifetime birth expectations of currently married women a close approximation of all women in a cohort. The analysis also indicates that the observed intracohort declines in lifetime birth expectations since 1967 were due largely to the addition at subsequent survey dates of previously unmarried women; nevertheless, some "true" cohort declines also seem to have occurred.

Adolescent↗
PubMedDate not supplied

Relaxation training as a nursing intervention versus pro re nata medication.

To determine the effect of relaxation training on the frequency of intake of pro re nata medication for relief of tension and to compare the difference between live and taped instructions of this training 60 patients on PRN minor tranquilizers and sedatives in one nursing unit were studied. Subjects were randomly assigned to three groups: group A, control; group B, live instruction; group C, taped instruction. Dependent variables monitored were: 1) frequency of intake of PRN medication; 2) pre- and postinstruction change in blood pressure, pulse, and respiration; 3) change in the Taylor Manifest Anxiety Scale; and 4) change on the Minnesota Multiphasic Personality Inventory score. Although no significant difference was found between method of relaxation training, there was evidence that group B surpassed group C in terms of benefit of the treatment. Physiologic variables as well as MMPI scales K, I, and VII yielded better results for group B. Not all variables demonstrated significant differences. Groups B and C were more similar at the conclusion of the study than had been anticipated-perhaps because subjects responded favorably to inclusion in the study regardless of method of training.

Analysis of Variance↗