Search PubMed⌕ Search

Biomedical subjects

M Krueger

Publications and source records attributed to M Krueger.

27 records · Page 2Linked to original sources
PubMed1984

Evidence for two copper atoms/subunit in dopamine beta-monooxygenase catalysis.

The stoichiometry of the copper requirement for the dopamine beta-monooxygenase-catalyzed conversion of dopamine to norepinephrine has been investigated by rapid chemical-quench techniques. This approach, which employs concentrated samples of enzyme, overcomes ambiguities of interpretation arising from levels of trace copper in excess of enzyme concentrations normally added to steady state kinetic assays. Low turnover numbers are observed when rapid quench kinetic studies are performed under conditions in which enzyme concentrations (2.5-7.1 microM) are in excess over trace copper levels (about 0.7 microM). The addition of exogenous Cu(II) results in full restoration of activity, which is maximal at a stoichiometry of 2 mol of copper/mol of enzyme subunit. From the dependence of catalytic activity on copper levels we conclude that both coppers are required for catalysis. No stimulation of activity was observed upon addition of the following metal ions: Ni(II), Co(II), Mn(II), Fe(III), and Zn(II). In addition, the magnitude of the tritium isotope effect for [2-3H]dopamine hydroxylation is invariant over a large range of enzyme activities accompanying changes in the ratio of copper to enzyme concentration. These results appear to rule out an effector role for the second mole of copper/subunit, implicating both copper atoms in active site redox chemistry.

Animals↗
PubMed1976

[Not Available].

Explore the source record for details and available documents.

Germany↗
PubMedDate not supplied

Cranial computed tomography interpretation in acute stroke: physician accuracy in determining eligibility for thrombolytic therapy.

CONTEXT: Intracranial hemorrhage must be excluded prior to administration of thrombolytic agents in acute stroke. OBJECTIVE: To evaluate physician accuracy in cranial computed tomography scan interpretation for determining eligibility for thrombolytic therapy in acute stroke. DESIGN: Administration of randomly selected, randomly ordered series of 15 computed tomography scans from a pool of 54 scans that demonstrated intracerebral hemorrhage, acute infarction, intracerebral calcifications (impostor for hemorrhage), old cerebral infarction (impostor for acute infarction), and normal findings. PARTICIPANTS: A convenience sample of 38 emergency physicians, 29 neurologists, and 36 general radiologists. MAIN OUTCOME MEASURES: Physician determination of eligibility for thrombolytic therapy based on computed tomography scan interpretation. RESULTS: Average correct score by all physicians on all computed tomography scans was 77% (95% confidence interval, 74%-80%). Of 569 computed tomography readings by emergency physicians, 67% were correct; of 435 readings by neurologists, 83% were correct; and of 540 readings by radiologists, 83% were correct. Overall sensitivity for detecting hemorrhage was 82% (95% confidence interval, 78%-85%); 17% of emergency physicians, 40% of neurologists, and 52% of radiologists achieved 100% sensitivity for identification of hemorrhage. CONCLUSION: Physicians in this study did not uniformly achieve a level of sensitivity for identification of intracerebral hemorrhage sufficient to permit safe selection of candidates for thrombolytic therapy.

Brain↗
PubMedDate not supplied

Descriptions of self: an exploratory study of adolescents with ADHD.

PROBLEM: How do adolescents experience attention deficit hyperactivity disorder (ADHD), and how are those experiences shaped and managed? METHODS: A qualitative exploratory design to investigate how adolescents with ADHD (N = 11; 8 males, 3 females) experience, perceive, and manage ADHD. Findings are based on a subset of data from a large grounded theory study of the experiences of living in a family when a child or adolescent has ADHD. The constant comparative method was used to analyze both individual and focus group interview data. FINDINGS: The primary finding, presented as a hypothesis, suggests that an ADHD adolescent's sense of self is distorted and that the development of self has been disrupted due to the neurobiology of ADHD and environmental factors associated with the difficulties of parenting a difficult child, social role expectations, and modeling. CONCLUSIONS: Therapeutic attention to how the self functions is important in stabilizing and ordering an adolescent's sense of self. Intrapsychic psychotherapy may be an important therapeutic approach in helping adolescents with ADHD develop personal responsibility and increased capacity for empathy.

Adolescent↗