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Biomedical subjects

C Grady

Publications and source records attributed to C Grady.

51 records · Page 3Linked to original sources

Positron emission tomography in Alzheimer's disease.

Twenty-one patients with a clinical diagnosis of dementia of the Alzheimer's type (DAT) and 29 healthy, age-matched controls were studied using positron emission tomography (PET) and [18F]2-fluoro-2-deoxy-D-glucose to measure regional cerebral glucose consumption in the resting state. Reductions in ratio measures of relative metabolism in some parietal, temporal, and frontal regions were found in mild, moderate, and severe DAT groups. A significant increase in right/left metabolic asymmetry, particularly in parietal regions, also was seen in mild and moderate groups. Only in the severely demented patients was the absolute cerebral metabolic rate reduced significantly from control values. Fourteen patients had repeated PET studies, but only those patients with moderate to severe dementia showed a decline in IQ over 6 to 15 months. There were no significant changes in metabolic measures over time. PET is useful in quantifying regional cerebral dysfunction in DAT, even in the early stages of the disease.

Aged↗

Brain metabolism in autism. Resting cerebral glucose utilization rates as measured with positron emission tomography.

The cerebral metabolic rate for glucose was studied in ten men (mean age = 26 years) with well-documented histories of infantile autism and in 15 age-matched normal male controls using positron emission tomography and (F-18) 2-fluoro-2-deoxy-D-glucose. Positron emission tomography was completed during rest, with reduced visual and auditory stimulation. While the autistic group as a whole showed significantly elevated glucose utilization in widespread regions of the brain, there was considerable overlap between the two groups. No brain region showed a reduced metabolic rate in the autistic group. Significantly more autistic, as compared with control, subjects showed extreme relative metabolic rates (ratios of regional metabolic rates to whole brain rates and asymmetries) in one or more brain regions.

Adolescent↗

Human brain glucose utilization and cognitive function in relation to age.

Brain oxidative metabolism was examined with positron emission tomography and [18F]2-deoxy-D-glucose in 40 healthy men aged 21 to 83 years, under conditions of reduced visual and auditory stimulation. The mean cerebral metabolic rate for glucose (CMRglc) equaled 4.6 to 4.7 mg X 100 gm-1 X min-1 and did not correlate significantly with age (p greater than 0.05). Regional cerebral metabolic rates for glucose (rCMRglc) and Q ratios (rCMRglc/CMRglc), which had lower coefficients of variation than did rCMRglc, also did not correlate with age. Hyperfrontality of cerebral metabolism was absent at all ages. Age decrements were demonstrated in the error score on the Benton Revised Visual Retention Test and in the Performance Subtest scaled score of the Wechsler Adult Intelligence Scale (WAIS) but not in the Verbal Subtest scaled score of the WAIS. The cognitive test scores did not correlate with brain metabolic rates. The results indicate that brain oxidative metabolism, when measured under resting conditions with reduced sensory input, is not reduced in relation to age in healthy men. Furthermore, no significant relations between intelligence and resting cerebral metabolism are evident.

Adult↗

Down's syndrome in adults: brain metabolism.

The cerebral metabolic rate for glucose, as measured with positron emission tomography and fluorine-18-labeled 2-deoxy-D-glucose, was significantly higher in four healthy young subjects with trisomy 21 syndrome (Down's syndrome) than the mean rate in healthy young controls. The rate of cerebral glucose utilization in the frontal lobe of a 51-year-old subject with Down's syndrome was significantly lower than the rate in the young subjects with this syndrome, but approximated the rate in middle-aged controls. Thus glucose utilization by the brain appears to be excessive in young adults with Down's syndrome but may decline with age in some brain regions.

Adult↗

Cerebral glucose utilization, as measured with positron emission tomography in 21 resting healthy men between the ages of 21 and 83 years.

Positron emission tomography (PET) scanning with 18F-2-deoxy-D-glucose was employed to examine hemispheric and regional rates of cerebral glucose utilization in 21 resting healthy men between the ages of 21 and 83 years. The eyes of the subjects were covered and the external auditory canals were plugged with cotton in the 45 minutes following injection of tracer. Mean hemispheric cerebral metabolic rates for glucose (CMRglc) averaged 4.3 to 4.4 mg x 100 g-1 X min-1, and mean hemispheric grey matter glucose utilization, (CMRglc)grey, averaged 5.2 to 5.3 mg x 100 g-1 X min-1. Neither parameter was correlated significantly with age, nor were their right/left ratios correlated with age (P greater than 0.05). The mean ratios, furthermore, did not differ significantly from 1. Regional cerebral metabolic rates for glucose, rCMRglc, at each of 31 identified midline and bilateral structures also were not correlated significantly with age. Mean rCMRglc ranged from 2.6 mg X 100 g-1 X min-1 at the centrum semiovale to 6.2 mg . 100 g-1 X min-1 at the precentral gyrus of the frontal lobe and precuneus of the parietal lobe. The results indicate that the cerebral metabolic rate for glucose is not correlated with age in healthy men.

Adult↗

What makes clinical research ethical?

Many believe that informed consent makes clinical research ethical. However, informed consent is neither necessary nor sufficient for ethical clinical research. Drawing on the basic philosophies underlying major codes, declarations, and other documents relevant to research with human subjects, we propose 7 requirements that systematically elucidate a coherent framework for evaluating the ethics of clinical research studies: (1) value-enhancements of health or knowledge must be derived from the research; (2) scientific validity-the research must be methodologically rigorous; (3) fair subject selection-scientific objectives, not vulnerability or privilege, and the potential for and distribution of risks and benefits, should determine communities selected as study sites and the inclusion criteria for individual subjects; (4) favorable risk-benefit ratio-within the context of standard clinical practice and the research protocol, risks must be minimized, potential benefits enhanced, and the potential benefits to individuals and knowledge gained for society must outweigh the risks; (5) independent review-unaffiliated individuals must review the research and approve, amend, or terminate it; (6) informed consent-individuals should be informed about the research and provide their voluntary consent; and (7) respect for enrolled subjects-subjects should have their privacy protected, the opportunity to withdraw, and their well-being monitored. Fulfilling all 7 requirements is necessary and sufficient to make clinical research ethical. These requirements are universal, although they must be adapted to the health, economic, cultural, and technological conditions in which clinical research is conducted. JAMA. 2000;283:2701-2711.

Beneficence↗

Grappling with global concerns in the search for an HIV vaccine.

There is a need for increasing international collaboration in the search for a safe and effective HIV vaccine. In addition to the ethical issues that must be considered in conducting any clinical research, unique issues arise in vaccine research and in international research. Careful deliberation and guideline development regarding the ethics of international vaccine research was the focus of a series of recent consultations sponsored by Joint United Nations Programme on HIV/AIDS (UNAIDS) around the world.

AIDS Vaccines↗

Investigating chronic symptoms in HIV: an opportunity for collaborative nursing research.

Because of improved life expectancy for people with HIV infection, today's clinician needs to understand and manage chronic symptoms that limit function and quality of life. The authors describe two collaborative HIV symptom-management studies conducted by the Division of Intramural Research of the National Institute of Nursing Research. Studies such as these are necessary to provide nurses and other healthcare personnel with the knowledge essential for appropriate, comprehensive, and quality patient care.

Chronic Disease↗

Body composition in clinically stable men with HIV infection.

Clinically stable HIV-infected men (N = 106) receiving investigational antiretrovirals were recruited. Subjects were divided into three HIV disease severity groups by CD4+ cell count. Standard measures of body composition were assessed, as well as serum measures of visceral protein stores and kilocalorie intake. Group 1 subjects (CD4+ T cells < 200) had significantly lower measures of body fat as compared with Group 2 (CD4 between 200 and 600) and Group 3 (CD4 > 600) despite adequate kilocalorie intake. Group 2 and Group 3 were not significantly different from each other. Our entire cohort had significantly lower muscle mass compared to norms. Our data demonstrate that people with advanced HIV disease have reduced muscle and fat.

Adult↗

Fatigue in HIV-infected men receiving investigational interleukin-2.

BACKGROUND: Although fatigue is an almost universal clinical complaint of people with human immunodeficiency virus (HIV) infection, little has been done to study systematically the etiology, frequency, severity, response to, or management of HIV-related fatigue. In addition, HIV-related treatments may contribute to fatigue. OBJECTIVES: To describe the extent and severity of perceived fatigue in a cohort of HIV-infected men (N= 50) who, as participants in a randomized clinical trial, were randomized to receive or not to receive investigational interleukin-2 (IL-2). METHOD: A modified Piper Fatigue Scale was used to measure fatigue at baseline, at the end of 5 days of IL-2 therapy, 1 week later at home, and 1 month later for three consecutive cycles of IL-2 therapy. RESULTS: Against a variable background of baseline fatigue in all subjects, those receiving IL-2 reported a significant increase in their level of fatigue after receiving IL-2. Fatigue levels remained elevated 1 week later but returned to baseline by 1 month. Fatigue was related to the dose of IL-2 but not to the reported amount or quality of sleep. CONCLUSIONS: Against a background of fatigue related to HIV infection and its multiple manifestations and treatments, therapy with IL-2 dramatically increases the experience of fatigue. Although this increase is transient and tends to return to baseline by 1 month, during that month the patient's life function and quality may be severely affected.

Adult↗

A comparison of calculated energy requirements to measured resting energy expenditure in HIV-1-infected subjects.

Twenty HIV-infected outpatients participating in clinical drug trials of the National Institute of Allergy and Infectious Diseases (NIAID) and enrolled in the collaborative National Institute of Nursing Research (NINR) nutrition study underwent indirect calorimetry measurements. Energy requirements for these subjects also were calculated using the Harris Benedict Equation (HBE). In all 20 subjects, the calculated energy requirements underestimated actual resting expenditure as determined by indirect calorimetry.

Activities of Daily Living↗

Laboratory methods for diagnosing and monitoring HIV infection.

The authors provide a brief review of laboratory methods used to diagnose infection, monitor HIV disease progression, and monitor response to treatment in the HIV-infected person. Included are descriptions of the characteristics of the HIV virus, and the immune damage that results from HIV infection. The authors describe the antibody tests, tests of the virus, "surrogate markers" of disease progression, and immune parameters. Nurses' understanding of these tests will facilitate effective patient monitoring and education.

AIDS Serodiagnosis↗