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Biomedical subjects

N L Foster

Publications and source records attributed to N L Foster.

At least 73 records · Page 4Linked to original sources
PubMed1985

CSF dopamine-beta-hydroxylase activity in Parkinson's disease.

Although the most prominent neurochemical change in parkinsonism is nigrostriatal dopamine deficiency, norepinephrine content is also diminished in the CNS. In this study, dopamine-beta-hydroxylase (DBH) activity, a marker of central noradrenergic activity, was measured in the CSF of previously unmedicated parkinsonian patients and normal controls. The parkinsonian patients showed a reduction in CSF DBH levels to 41% of control values (p less than 0.01). Possible explanations for the decrease included a decreased noradrenergic nerve pool or a diminished rate of synthesis of catecholamines.

Adult↗
PubMed1985

Dystonia: treatment with bromocriptine.

As with parkinsonism, certain dystonias may involve disturbances in dopaminergic neurotransmission. The effects of bromocriptine, 18-150 mg/day (mean, 72.5), were studied in 15 patients with a variety of dystonic disorders, using a double-blind, crossover format. Of the 13 patients completing several weeks of medication, seven improved more than 10% and two worsened, on clinical ratings, while five recognized improvement in disability. Dopaminomimetic agents such as bromocriptine, used in the dose range effective for treating parkinsonism, may yield symptomatic improvement with several patterns of dystonia.

Adult↗
PubMed1984

Wechsler Adult Intelligence Scale performance. Cortical localization by fluorodeoxyglucose F 18-positron emission tomography.

We compared local cerebral glucose metabolism, as determined by positron emission tomography following administration of fluorodeoxyglucose F 18, with Wechsler Adult Intelligence Scale (WAIS) scores in 22 right-handed persons. Five study subjects were normal volunteers and the remainder had Alzheimer's disease. Subtest scores within the verbal IQ group or the performance IQ group were generally highly interrelated; there was usually no correlation between the verbal and performance subtests. The cortical distribution of regions in which glucose metabolism was most closely associated with verbal subtest scores generally centered in the left parasylvian area. In contrast, scores on the performance subtests mainly localized to the right posterior parietal region. Most WAIS subtests thus appeared to evaluate primarily either verbal or visuospatial cognitive functions and either left parasylvian or right posteroparietal cortical activity.

Aged↗
PubMed1984

Regional cortical dysfunction in Alzheimer's disease as determined by positron emission tomography.

Local cerebral glucose metabolism and psychometric function were compared in 17 patients with Alzheimer's disease and 5 healthy age-matched controls. Performance on tests of global intellectual function averaged 30 to 45% lower in the Alzheimer's group. Mean cortical glucose metabolism, as determined by positron emission tomography following fluorine-18-labeled fluorodeoxyglucose administration, was reduced by 30% in the Alzheimer's group. There was a significant positive correlation between the degree of overall dementia and the amount of metabolic reduction. The distribution of cortical hypometabolism was not uniform: the posterior parietal lobes and contiguous portions of the posterior temporal and anterior occipital lobes were most severely involved. The frontal cortex was relatively spared. These findings are compatible with the major clinical deficits found in patients with Alzheimer's disease and may help focus future biochemical probes into the pathophysiology of this disease.

Alzheimer Disease↗
PubMed1984

Peripheral beta-adrenergic blockade treatment of parkinsonian tremor.

The effect of nadolol, a peripherally acting beta-adrenergic blocker, on resting, postural, and intention tremor was examined in 8 patients with idiopathic Parkinson's disease whose motor symptoms, other than tremor, were well controlled with conventional medications. In a double-blind, placebo-controlled, crossover design, patients received 80 to 320 mg of nadolol for six weeks while continuing their previous therapeutic regimen. Accelerometer readings showed a 34% reduction (p less than 0.025) in tremor distance, but no change in tremor frequency, during nadolol therapy. Maximum benefit was achieved with a dose of 240 mg, when resting tremor improved 54%, postural tremor 32%, and intention tremor 54%. Physician ratings and patient reports supported the accelerometer results. Nadolol appears to be a safe, effective adjunct to current dopaminergic and anticholinergic therapy for severe tremor in Parkinson's disease.

Adrenergic beta-Antagonists↗
PubMed1984

Cortical abnormalities in Alzheimer's disease.

Regional cerebral glucose metabolism, an index of neuronal activity, was compared in 20 patients with Alzheimer's disease and 8 age-matched normal volunteers by positron emission tomography following [18F]2-fluoro-2-deoxy-D-glucose administration. Overall cortical glucose utilization in the Alzheimer's group was 10 to 49% below that of control individuals. The posterior parietal cortex and contiguous portions of posterior temporal and anterior occipital lobes were most severely affected; frontal cortex was relatively spared. This pattern of cortical involvement is consistent with the major clinical features of Alzheimer's disease. Comparison of patients with early and more advanced dementia suggested that a substantial decline in glucose metabolism occurs before cognitive impairment becomes evident; once the patient is symptomatic, however, small additional metabolic decrements are associated with a marked deterioration in intellectual function.

Aged↗
PubMed1984

Treatment of resting tremor by beta-adrenergic blockade.

The effect of nadolol, a peripherally acting beta-adrenergic blocker, on resting tremor was examined in eight patients with idiopathic Parkinson's disease. With the use of a double-blind, placebo-controlled study of crossover design, patients received 80 to 320 mg of nadolol for 6 weeks while continuing their previous treatment regimen. Accelerometer readings showed a progressive reduction in tremor amplitude, but no change in tremor frequency, with increasing nadolol dosage. Maximum benefit was achieved at 240 mg, when resting tremor improved 50% (p less than 0.01). Physician ratings confirmed these findings. The results suggest that response to beta-adrenergic blockade may not be limited to postural or intention tremor and that such agents may not reliably differentiate between the tremor of Parkinson's disease and essential tremor.

Adrenergic beta-Antagonists↗
PubMed1984

Blink rates and disorders of movement.

Blink rate, a putative noninvasive marker of central dopamine activity, was assessed in medication-free patients with Parkinson's disease, progressive supranuclear palsy, Huntington's disease, and dystonia. The normal control rate of 24 blinks per minute was significantly higher than the rate of 12 and 4 blinks per minute recorded for patients with Parkinson's disease and progressive supranuclear palsy, respectively. The rates for patients with Huntington's disease and dystonia did not differ significantly from those of controls (36 and 26 blinks per minute, respectively).

Adult↗
PubMed1983

THIP treatment of Huntington's disease.

We evaluated the therapeutic efficacy of gamma aminobutyric acid (GABA) system stimulation in four patients with classical Huntington's disease and one with the hypokinetic-rigid form. Orally administered THIP (4,5,6,7-tetrahydroisoxazolo-[5,4,-c] pyridin-3-ol), a novel GABA receptor agonist, failed to improve motor or cognitive function during a 2-week trial. At maximum levels, THIP mimicked another putative GABA agonist, muscimol, in causing unsteadiness of gait, diminished attention to sensory stimuli, and somnolence. These effects suggest that central GABA systems participate in the regulation of some human and behavioral functions. CSF content of homovanillic acid, a major metabolite of dopamine, increased during high-dose THIP therapy, suggesting that augmentation of dopaminergic function may have contributed to the drug's lack of efficacy.

Adult↗
PubMed1983

Alzheimer's disease: focal cortical changes shown by positron emission tomography.

Local rates of cortical glucose metabolism were estimated by positron emission tomography in 13 right-handed patients with Alzheimer's disease. Individuals with disproportionate failure of language function had markedly diminished metabolism in the left frontal, temporal, and parietal regions. Patients with predominant visuo-constructive dysfunction evidenced a hypometabolic focus in the right parietal cortex. Patients with memory failure as the most apparent feature had no significant metabolic asymmetry in cortical regions. In all subjects, verbal competency generally correlated with metabolic activity in the left frontal and temporal areas, while visuo-constructive test performance was linked to glucose utilization in the right parietal lobe.

Aged↗
PubMed1980

Progressive supranuclear palsy and hyperkalemic periodic paralysis.

A patient with hyperkalemic periodic paralysis experienced the gradual onset of additional and unexpected neurologic abnormalities in middle age, suggestive of progressive supranuclear palsy. Although the concurrence of these findings may be coincidental, these features may evade recognition in other patients by being misattributed to chronic myopathy or depression.

Bulbar Palsy, Progressive↗
PubMed1980

Metrizamide ventriculography in syringomyelia.

Computed tomography (CT) both with and without contrast agents has been used to diagnose syringomyelia. We report a case in which the diagnosis was made by injection of metrizamide into a ventriculoperitoneal shunt. Continuity of the syringomyelic cavity with the ventricular system was demonstrated. This case supports the hydrodynamic concept of syringomyelia formation and illustrates a potentially useful approach to its diagnosis.

Biomechanical Phenomena↗
PubMedDate not supplied

Balanced centralized and distributed database design in a clinical research environment.

Clinical research databases can meet both research and clinical needs, but this ideal is seldom achieved. Priorities often differ for those who collect and ultimately use the data and those who develop data systems. Traditional database designs also create logistical barriers that hamper communication. The Michigan Alzheimer's Disease Research Center has developed a secure, distributed data system with centralized data entry that provides an intuitive, individually customized interface for investigators in their clinics, laboratories and offices. Data are kept in a form that can be readily understood without reference to a code-book. Investigators can modify and query their own copies of the database without knowledge of programming languages. Balancing centralized and distributed designs for research databases enhance the accuracy and completeness of data collection and increases the use of data for research and clinical care.

Aged↗