PubMed Health⌕ Search

Biomedical subjects

T W May

Publications and source records attributed to T W May.

5 recordsLinked to original sources
PubMed1992

Effects of withdrawal of phenytoin on cognitive and psychomotor functions in hospitalized epileptic patients on polytherapy.

The effects of the withdrawal of phenytoin (PT) on cognitive and psychomotor functions of long-term patients in an epilepsy centre were studied. The patients had been treated for many years (31.1 +/- 10.8 yrs.) with PT in combination with other antiepileptic drugs. The serum concentration of PT was in the lower to middle therapeutic range (6.8 +/- 3.1 mg/l). Only patients in which the efficacy of PT was questionable were included in the study. PT was withdrawn in 17 patients. The PT dose was not changed in 12 patients (control group). Psychological tests were carried out immediately before the withdrawal of PT and about 10 weeks later. Tests were also carried out with the control group at the same time. A significantly improved performance (using a composite score) was noted after the withdrawal of PT. The statistical evaluation of the different tests showed an significant improvement in one test of concentration and two tests of psychomotor function (tapping and pursuit rotor with the dominant hand). There was no significant change in the frequency of seizures.

Adult↗
PubMed1991

Nomogram for the prediction of unbound phenytoin concentrations in patients on a combined treatment of phenytoin and valproic acid.

The interpretation of the total phenytoin (PT) concentration can be problematic if valproic acid (VPA) is given as a comedication, because VPA displaces PT from the protein binding sites and can increase the free fraction of PT. In order to estimate the free or unbound PT concentration (PTf) from the total PT concentration (PTt) and VPA concentration, a nomogram was constructed and evaluated. Data of 84 patients on combined therapy with PT and VPA were used in drawing up the regression equation (PTf = 0.0792.PTt + 0.000636.PTt.VPA) from which the nomogram was constructed. The predictions were checked using another 33 patients whose serum concentrations were determined in the morning and in addition several times during the day. The results show that using this method the PTf concentrations can be accurately estimated from the PTt and VPA concentrations.

Adolescent↗
PubMed1988

Trace element residues in bluegills and common carp from the lower San Joaquin River, California, and its tributaries.

Whole-body samples of bluegills (Lepomis macrochirus) and common carp (Cyprinus carpio) from the San Joaquin River and two tributaries (Merced River and Salt Slough) were analyzed to determine if the concentrations of any of nine elements were elevated as a result of exposure of the fish to agricultural subsurface (tile) drainage water. Highest concentrations (micrograms/g dry weight) detected were as follows (first number in each pair applies to bluegills and the second to carp): arsenic (As), 0.97 and 1.5; boron (B), 14 and 20; cadmium (Cd), 0.14 and 0.27; chromium (Cr), 2.7 and 2.2; mercury (Hg), 3.3 and 2.9; molybdenum (Mo), 2.8 and 3.6; nickel (Ni), 0.87 and 2.2; lead (Pb), 0.26 and 2.3; and selenium (Se), 3.2 and 5.5. The lowest concentrations were below the levels of detection, except for Hg (0.15 in bluegills and 0.12 in carp) and Se (0.43 and 0.56). As judged by comparisons with data from the National Contaminant Biomonitoring Program and other published surveys, the concentrations of B, Hg, Mo, and Se were moderately elevated in fish from several sites in the San Joaquin Valley. However, only the Se concentrations were positively correlated with water quality variables (e.g., total alkalinity, conductivity, and turbidity) known to be influenced by irrigation return flows. Historical data from one site (Salt Slough), where trace elements in whole fish have been measured since 1969, indicated that Se concentrations increased more than twofold between 1973 and 1977, but thereafter remained near 3.0 micrograms g-1 (dry weight basis), presumably due to the continuing practice of disposing seleniferous tile drainage water into the most convenient stream channel.

Animals↗