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Biomedical subjects

P Fox

Publications and source records attributed to P Fox.

At least 109 records · Page 6Linked to original sources
PubMed1979

LSD's effect on neuron populations in visual cortex gauged by transient responses of extracellular potassium evoked by optical stimuli.

The effects of systemic LSD (10--25 micrograms/kg) on visually evoked [K+]o responses from the striate cortex have been investigated in cats. Elevation of [K+]o was dependent on the orientation, and direction of stimulus movement and showed ocular dominance. LSD most commonly produced a depression of [K+]o transients and a deterioration in their directional selectivity. These observations suggest that the effect of LSD is to produce a net depression in visually evoked neuronal firing.

Animals↗
PubMed1979

Assessment of the antihypertensive effect of atenolol with 24 h ambulatory monitoring of blood pressure.

1. Twenty-four hour intra-arterial blood pressure measurements and electrocardiograms were obtained from 12 subjects with untreated essential hypertension. 2. The patients kept records of their activity, paying particular attention to times of retiring to bed, and times of waking in the morning. 3. All subjects were treated with a single daily dose of atenolol (50 to 200 mg) for between 2 and 9 months, and then underwent a second 24 h blood pressure study. 4. Arterial blood pressure was lowered significantly throughout the 24 h period with a single daily dose of atenolol.

Adult↗
PubMed1978

The effect of mental arithmetic on blood pressure variability and baroreflex sensitivity in man.

1. Baroreflex sensitivity was tested in three normal, three borderline and one hypertensive subject before and during mental arithmetic, the prolongation of pulse interval caused by a provoked rise in blood pressure being used as a measure of baroreflex sensitivity. 2. Baroreflex sensitivity was significantly decreased during mental arithmetic. 3. During mental arithmetic the arterial pressure fluctuated markedly. 4. These findings suggest that in man, as well as animals, the defence of alerting reaction depresses baroreflex control and thus contributes to the rise in blood pressure seen at this time.

Blood Pressure↗
PubMed1978

A comparison of the biological and biochemical properties of 1-(4-amino-2-methylpyrimidin-5-yl)methyl-3-(2-chloroethyl)-3-nitrosourea and 2-[3-(2-chloroethyl)-3-nitrosoureido]-D-glucopyranose.

1-4-Amino-2-methylpyrimidin-5-yl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU) is a water-soluble nitrosourea that has produced delayed hematological toxicity in man during Phase 1 clinical trials. ACNU has in vitro alkylating activy 40% less than that of 2-[3-(2-chloroethyl)-3-nitrosoureido]-D-glucopyranose (chlorozotocin) but shares the property of negligible carbamoylating activity with the latter compounds. ACNU is highly active against murine L1210 leukemia. However, the maximum therapeutic dose, 30 mg/kg (a dose lethal to 10% of the animals), produced a 64% reduction in peripheral WBC and an 85% decrease in circulating neutrophils in normal mice. This was correlated with a 76% inhibition of normal mouse bone marrow DNA synthesis within 24 hr after treatment, followed by full recovery within 48 hr after treatment, followed by full recovery within 48 hr. In contrast, DNA synthesis in L1210 cells was suppressed to less than 10% of control for a minimum of 72 hr. While ACNU, a pyrimidine analog, possesses many of the chemical properties of chlorozotocin, it does not share with the latter compound its reduced myelotoxicity at therapeutic doses. The glucose carrier of the chlorozotocin molecule appears to impart the selective sparing of normal bone marrow.

Animals↗
PubMedDate not supplied

Lessons learned from the Medicare Alzheimer Disease Demonstration.

The Medicare Alzheimer Disease Demonstration tested a case management and community care benefit for persons with dementia. The demonstration produced statistically but not clinically significant reductions in caregiver burden and depression. It increased access to community-based long-term care services but did not affect the level of services used. It did not reduce informal caregiver hours spent helping people with dementia. It produced statistically significant but not budget-neutral reductions in Medicare expenditures in that the degree of reduction in regular Medicare expenditures was not enough to offset the added demonstration costs. It did not reduce rates of nursing home placement. Informal care networks providing care to demented enrollees were generally able to function effectively, regardless of whether a professional case manager was involved or whether a long-term care benefit was available.

Aged↗
PubMedDate not supplied

Regional spatial normalization: toward an optimal target.

PURPOSE: The purpose of this work was to develop methods for defining, constructing, and evaluating a "minimal deformation target" (MDT) brain for multisubject studies based on analysis of the entire group. The goal is to provide a procedure that will create a standard, reproducible target brain image based on common features of a group of three-dimensional MR brain images. METHOD: The average deformation and dispersion distance, derived from discrete three-dimensional deformation fields (DFs), are used to identify the best individual target (BIT) brain. This brain is assumed to be the one with the minimal deformation bias within a group of MR brain images. The BIT brain is determined as the one with the minimal target quality score, our cost function based on the deformation displacement and dispersion distance. The BIT brain is then transformed to the MDT brain using an average DF to create an optimized target brain. This analysis requires the calculation of a large number of DFs. To overcome this limitation, we developed an analysis method (the fast method) that reduces the task from order N2 complexity to one of order N, a tremendous advantage for large-N studies. RESULTS: Multiscale correlation analysis in a group of 20 subjects demonstrated the superiority of warping using the MDT target brain, made from the BIT brain, over several individual and MDT-transformed target brains also from the group. CONCLUSION: Analysis of three-dimensional DF provides a means to quickly create a reproducible MDT target brain for any set of subjects. Warping to the MDT target was shown by an independent multiscale correlation method to produce superior results.

Adult↗
PubMedDate not supplied

Effects of long-term, once-daily administration of atenolol on ambulatory blood pressure of hypertensive patients.

We measured intraarterial, ambulatory blood pressure over a 24-h period in 12 subjects 24--63 years (mean 47.6) of age with newly diagnosed untreated hypertension. Measurements were performed both before and after 2--9 months of once-daily treatment with atenolol, a cardioselective beta-adrenoceptor antagonist. Significant reductions in arterial pressure (p less than 0.005) during treatment with atenolol (dose range 50--200 mg) were observed over the full 24-h period.

Adult↗
PubMedDate not supplied

A four-dimensional probabilistic atlas of the human brain.

The authors describe the development of a four-dimensional atlas and reference system that includes both macroscopic and microscopic information on structure and function of the human brain in persons between the ages of 18 and 90 years. Given the presumed large but previously unquantified degree of structural and functional variance among normal persons in the human population, the basis for this atlas and reference system is probabilistic. Through the efforts of the International Consortium for Brain Mapping (ICBM), 7,000 subjects will be included in the initial phase of database and atlas development. For each subject, detailed demographic, clinical, behavioral, and imaging information is being collected. In addition, 5,800 subjects will contribute DNA for the purpose of determining genotype- phenotype-behavioral correlations. The process of developing the strategies, algorithms, data collection methods, validation approaches, database structures, and distribution of results is described in this report. Examples of applications of the approach are described for the normal brain in both adults and children as well as in patients with schizophrenia. This project should provide new insights into the relationship between microscopic and macroscopic structure and function in the human brain and should have important implications in basic neuroscience, clinical diagnostics, and cerebral disorders.

Adolescent↗
PubMedDate not supplied

An acute problem.

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Aged↗
PubMedDate not supplied

Mental health: financial arrangements for long-stay residents.

The process of preparing long-stay patients for relocation from mental health hospitals to the community has been well described, but little attention has been paid to the effects such a move has on arrangements for residents' finances. This article describes a system which seemed to mix the best of the traditional hospital banking system with modern community-based commercial banking services, and how the provision of a financial service to a group of institutionalised residents assisted in the process of re-personalisation.

Adult↗
PubMedDate not supplied

Nursing developments: trust nurses' views.

Innovations in nursing require strong management. In this survey, the author sought the views of trust nurse executives on how the ideas of the UKCC's The Scope of Professional Practice and clinical supervision could be implemented. The results provide food for thought for nurses at all levels.

Education, Nursing, Continuing↗
PubMedDate not supplied

Short rations.

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England↗