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Biomedical subjects

K Hall

Publications and source records attributed to K Hall.

At least 397 records · Page 22Linked to original sources
PubMedDate not supplied

A multivariable analysis of factors governing the steady-state pharmacokinetics of valproic acid in 52 young epileptics.

A number of factors have been implicated in the interpatient variability of valproic acid (VPA) pharmacokinetics. These include patient age, concurrent anticonvulsant therapy, and dosage of VPA. In the clinical setting, it is important to determine which of these variables exert a major effect on the observed differences in VPA disposition. Accordingly, we analyzed the data from 52 young epileptic patients using multivariate statistical methods. Concurrent anticonvulsant therapy was the major determinant of VPA clearance in this patient population. The half-life of VPA was significantly related to age, but volume of distribution and clearance were not. The dosage of VPA affected the volume of distribution of VPA but not the half-life or clearance of this drug. These results provide a more rational understanding of VPA pharmacokinetics in the clinical setting and have implications for the monitoring and manipulation of VPA therapy in the epileptic population.

Adolescent↗
PubMedDate not supplied

'Z-RNA'--a left-handed RNA double helix.

In contrast to double-stranded DNA, there has so far been little evidence that double-stranded RNA can undergo major conformational transitions. We have investigated the conformation in different conditions of the double-stranded RNA molecule poly(G-C).poly(G-C), by NMR, circular dichroism and absorbance spectroscopy. We report here evidence obtained by these different spectroscopic techniques that poly(G-C).poly(G-C) undergoes a transition from the A-form to a left-handed Z-form in conditions of high ionic strength and at temperatures above 35 degrees C. This conformational transition may be of relevance to the biological situations in which double-stranded RNA occurs, such as in ribosomes and in some viruses.

Circular Dichroism↗
PubMedDate not supplied

Xp22.3 microdeletion in a 19-year-old girl with clinical features of MLS syndrome.

We describe a 19-year-old girl who has clinical features of microphthalmia with linear skin defects (MLS) syndrome caused by a microdeletion of Xp22.3. In addition to the classical ocular abnormalities and linear skin defects she has other features not previously described. She was previously reported in this journal in 1990 as poikiloderma congenitale, but her true diagnosis of an Xp22.3 microdeletion was clarified when fluorescent in situ hybridization (FISH) analysis indicated that one of her X chromosomes had a microdeletion including the KAL gene. We describe this patient with an Xp22.3 microdeletion to heighten awareness among dermatologists of this syndrome and to underscore the difficulties in diagnosing MLS syndrome.

Abnormalities, Multiple↗
PubMedDate not supplied

Peplau's model of nursing: caring for a man with AIDS.

Nursing models should be seen as an adaptable framework for care. Peplau's model of nursing centres on the interpersonal process and involves the client with a felt need and the nurse who has the knowledge to respond to the problem and be effective within the therapeutic process. When utilised effectively, negative energy can be channelled towards positive growth. Clients have a right to refuse nursing intervention. Confidentiality is paramount in building a trusting relationship.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Does nicotine have beneficial effects in the treatment of certain diseases?

Although tobacco smoking has long been associated with diseases of the lungs and cardiovascular system, numerous studies have demonstrated a negative association between tobacco smoking and ulcerative colitis, and the neurodegenerative diseases, Alzheimer's disease (AD) and Parkinson's disease (PD). The evidence suggests that nicotine--the main pharmacologically active ingredient of tobacco--appears to be responsible for this effect. Pure nicotine has no known carcinogenic properties and can be administered in numerous ways including transdermal patches and tablets. As a therapeutic agent, its association with tobacco can be likened to morphine and opium smoking. There is ample clinical evidence to suggest that nicotine could be beneficial in the treatment of some patients with diseases. Pharmacologically, nicotine acts on cholinergic (nicotinic-specific) receptors which are depleted in AD and PD. Nicotinic receptors also interact closely with several neurotransmitters including dopamine, which is implicated in both PD and Gilles de la Tourettes's syndrome. There is no doubt that tobacco smoking can be harmful and no-one should be encouraged to smoke. However, although nicotine has many harmful side-effects, it may have therapeutic value or at the very least be a useful tool for future drug development.

Alzheimer Disease↗
PubMedDate not supplied

First-dose and steady-state pharmacokinetics of valproic acid in children with seizures.

The serum concentration-time curve of valproic acid was followed in 25 children after single oral doses of the drug and at steady-state. Total body clearance (CL), half-life (t 1/2), and apparent volume of distribution (Vd) were calculated from the terminal portion of the curve and from the area under the serum concentration-time curve (AUC). The CL and Vd were significantly greater at steady-state (0.42 +/- 0.20 ml/min/kg and 0.231 +/- 0.067 L/kg, respectively) than after a single dose (0.32 +/- 0.13 ml/min/kg and 0.191 +/- 0.055 L/kg, respectively). This difference was most pronounced in patients with valproic acid dosage increases in excess of 20% and no change in their concurrent anticonvulsant therapy between the single-dose and steady-state study periods. The t 1/2 was not significantly different between the 2 study periods. There was a significant correlation between age and both CL and Vd after single doses and at steady-state. The t 1/2 did not appear to be age related. These results suggest that the adequacy of the dosage regimen must be determined during maintenance therapy rather than extrapolated from data obtained after a single dose. Re-evaluation of therapy as the child grows older may also be necessary in view of the age-related differences in valproic acid pharmacokinetics which this study has demonstrated.

Adolescent↗
PubMedDate not supplied

Mild traumatic brain injury in an insured population: subjective complaints and return to employment.

The great majority of traumatic brain injury (TBI) is of mild severity, with Glasgow Coma Scores (GCS) of 13-15, post-traumatic amnesia of less than 48 hours and brief, if any, hospitalization. All mild TBI admissions to hospital were provided with education in the form of a brief interview and a brochure on minor head trauma from the National Head Injury Foundation. Seventy-seven insured individuals with mild TBI were contacted by phone between 1 and 3 months post-injury to determine the frequency and severity of post-traumatic symptoms and the rate of return to work (RTW). Twenty-six per cent of those contacted had subjective complaints; 88% had returned to work or school; 16% of those returning did so with some symptoms. Only 45% of symptomatic individuals sought medical consultation for their condition when offered. Education about post-traumatic symptoms from the onset may provide sufficient reassurance to most individuals that future use of medical services is seen as unnecessary. Rate of RTW is relatively higher than reported in previous studies of mild TBI.

Activities of Daily Living↗
PubMedDate not supplied

Incidence and treatment of visual dysfunction in traumatic brain injury.

The incidence of visual dysfunction and effectiveness of visual exercises in acute traumatically brain injured inpatients in a rehabilitation programme were studied. Vision evaluation norms were established on 23 hospital staff. The evaluation was then administered to 51 inpatients within days after admission. An additional 21 patients were unable to participate, usually due to decreased cognition or agitation. Thirty of 51 (59%) scored impaired in one or more of the following: pursuits, saccades, ocular posturing, stereopsis, extra-ocular movements, and near/far eso-exotropia. For patients having dysfunction in pursuits or saccades, a 2-week baseline was followed by vision exercises. During the baseline interval patients were evaluated by an optometrist to verify therapists' findings. Six patients who participated in several weeks of treatment were evaluated at 2-week intervals by an independent rater. Progress is graphically illustrated. Conclusions were that the suitability of an inpatient vision programme, from our experience, is questionable. However, an initial evaluation proved valuable for informing staff of patients' visual status and for referral to an optometrist/ophthalmologist for further treatment.

Adolescent↗