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Biomedical subjects

M Hooker

Publications and source records attributed to M Hooker.

10 recordsLinked to original sources

Magnetic resonance imaging in a military setting: a utilization analysis.

A prospective study was conducted to evaluate the use of magnetic resonance imaging (MRI) by orthopedic surgeons and residents versus the use of MRI by non-orthopedically trained health care providers in diagnosing knee pathology. Fifty patients initially evaluated by members of one of these groups who underwent subsequent knee MRI evaluation were selected to participate. Two orthopedic examiners individually examined all patients, recording clinical diagnosis and the merit of MRI evaluation in each case. Clinical accuracy, sensitivity, and specificity were compared between groups based on MRI findings. Diagnostic accuracy was similar; however, the orthopedic group displayed greater sensitivity, suggesting better clinical assessment. The study examiners observed both groups using MRI equally inappropriately and found 62% of the imaging studies unjustified. We conclude that knee MRI is used inappropriately in the current military setting. An algorithm is proposed to guide the future use of MRI in the diagnosis and management of knee pathology.

Adult↗

How generalizable are the results of large randomized controlled trials of antiretroviral therapy?

OBJECTIVES: To examine the generalizability of two large randomized controlled clinical trials of antiretroviral therapy in HIV-infected individuals. METHODS: The demographic, clinical and laboratory characteristics of HIV-infected participants in two antiretroviral trials (Concorde and Delta) at three study sites were compared with those of two other groups of patients to whom the trial results would be applicable: eligible patients who were screened for the trials but who did not enrol, and eligible patients who were not approached or screened for the trials. RESULTS: Among enrolled participants in the Concorde and Delta trials there was an under-representation of patients who had acquired HIV infection heterosexually (P = 0.014) or through injecting drug use (P = 0.03), and a greater representation of homosexual men (P < 0.001) compared to non-enrolled participants. Trial participants in Concorde had significantly less advanced immunosuppression compared to non-trial participants (P = 0.0001), while in Delta the converse was true. Concorde participants were also much less likely to be lost to follow-up for more than a year (9%) compared to eligible but unscreened patients (40%) (P < 0.001), and screened but unenrolled patients (22%) (P = 0.035). CONCLUSIONS: In applying the findings of large randomized clinical trials, it is important to establish whether there are systematic differences between the characteristics of trial participants and eligible non-participants, which might affect the generalizability of the study results. A log of the characteristics of enrolled as well as eligible but non-enrolled patients should be maintained so that the representativeness of the trial population can be evaluated.

Adult↗

Serum vitamin B12 and transcobalamin levels in early HIV disease.

A cohort of asymptomatic human immunodeficiency virus (HIV) seropositive patients was followed over a 2 1/2-year period, to establish changes in serum vitamin B12 (B12) concentrations. Serum B12, CD4 count, and clinical progression to acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC) were measured. The unsaturated B12 binding capacities of the transcobalamins were also determined at the start of the study and compared to those from a homosexual HIV seronegative control group. The geometric mean of serum B12 in 218 asymptomatic HIV seropositive patients was significantly lower than of a homosexual HIV seronegative control group (P = 0.02) and the unsaturated B12 binding capacities of transcobalamins I and II were significantly higher in the asymptomatic patients compared with the same control group (P < 0.03, P < 0.0001, respectively). Fifty-nine of the asymptomatic HIV seropositive patients were followed over a 2 1/2-year period during which most had falling serum B12 levels (64%). Twelve patients progressed clinically to ARC or AIDS, of which nine had repeat serum B12 estimation prior to progression. All nine patients had or developed falling serum B12 levels without any evidence of an HIV-related bowel disorder. All patients progressing had falling CD4 counts. Subnormal serum B12 levels are common in HIV disease and occur at an early stage. B12 levels fall in most patients with time and may help predict those patients whose disease will progress the most rapidly.

Acquired Immunodeficiency Syndrome↗

Whose health is it? Views about decision-making and information-seeking from people with HIV infection and their professional carers.

The views of people with HIV and their professional carers about patients' views on involvement in decision-making and information-seeking were studied, using a standardized self-report instrument. Patients and staff reported high levels of desire for patients' involvement in their care, but there were important differences between groups. Staff had higher preference for patients' involvement in decision-making than the patients themselves, while the opposite was the case for information-seeking. There were differences between professional groups and symptomatic and asymptomatic patients, social workers generally reporting higher preference for patients' autonomy, while doctors reported lower levels. Symptomatic patients tended to have lower preference for autonomy than asymptomatic ones. The significance and practical implications of the findings are discussed.

Adult↗

Pharmacokinetics of 2-fluorodideoxycytidine (2FddC) in patients infected with human immunodeficiency virus.

1. The aim of this study was to estimate an oral dosage regimen of 2FddC giving peak plasma drug concentrations close to the antiretroviral IC50 of 150 ng ml-1. 2. A total of 55 doses (40 intravenous infusions and 15 oral solutions) were given to 21 patients. One group (n = 6-11) received single doses of 0.01 mg kg-1 intravenously (i.v.), 0.1 mg kg-1 i.v. and 0.1 mg kg-1 orally (p.o.) in that order. The other group (n = 8-10) received single doses of 0.03 mg kg-1 i.v., 0.3 mg kg-1 i.v. and 0.3 mg kg-1 p.o. in that order. Blood and urine samples were collected up to 24 h after each dose for drug assay by h.p.l.c.-u.v. 3. The peak plasma concentrations of 2FddC were proportional to dosage across the range 0.03 to 0.3 mg kg-1. After intravenous dosing, the mean (%CV) volume of distribution was 60 (28) 1 and the mean (CV%) plasma clearance was 23 (23) 1 h-1. On average, 71% of the dose was recovered unchanged in urine and renal clearance exceeded concurrent creatinine clearance. 4. Plasma concentrations reached mean peaks of 37 and 96 ng ml-1 after oral doses of 0.1 and 0.3 mg kg-1, respectively. The mean absolute bioavailability was 50% within a 95% confidence interval of 20 to 80%. 5. The adverse events were usually mild or moderate in severity and were generally attributed to the disease rather than the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗

Transmission of HIV to heterosexual partners of infected men and women.

Future heterosexual spread of HIV will in part depend on the efficiency of transmission from men to women and from women to men. We studied seventy-eight female sexual partners of men infected with HIV and 18 male sexual partners of infected women. Participants were interviewed concerning sexual practices, use of contraception and other risk factors for HIV infection. Fifteen out of 78 (19.2%) female partners and one out of eighteen (5.5%) male partners were seropositive for HIV antibody. All couples had practised vaginal intercourse. Seropositive female partners did not differ significantly from seronegative partners with regard to length of relationship, number of acts of vaginal intercourse, other sexual practices, stage of clinical disease in the index case, or numbers of other sexual partners in the last five years. In two women, seroconversion was documented after one act of unprotected sexual intercourse. The majority of infected female partners (eight out of 15) had sexual relationships with men who were asymptomatic and did not practice anal intercourse. Biological factors such as variability in infectivity of the index case and susceptibility of the contact, as well as behavioural variables may be important in determining transmission.

Adolescent↗

Disabled-worker beneficiaries under OASDI: comparison with severely disabled PA recipients.

The 1972 Survey of Disabled and Nondisabled Adults found that more than 1 million severely disabled persons aged 20-64 were receiving payments under Federal-State public assistance programs. To determine the reasons why most of these individuals did not qualify for disabled-worker benefits under the social security program, their characteristics were compared with those of the approximately 1.5 million disabled-worker beneficiaries. The public assistance recipients were found to be younger and less well educated than their disabled-worker beneficiary counterparts. A greater proportion of them were women and more were members of minority races. Public assistance recipients became disabled at an earlier age and had been disabled longer. Compared with disabled-worker beneficiaries, they had held less skilled jobs, had earned less money, and had had a weaker attachment to the labor force. These characteristics greatly reduced their chances of qualifying for disabled-worker benefits. Lack of knowledge about the program was also an important contributing factor.

Adult↗