Chromospheric Helium Imaging Photometer (an Instrument for High Time Cadence 1083-nm Wavelength Solar Observations).

The scientific motivation, design criteria, and specifications for a new ground-based instrument to observe the Sun in the He i 1083-nm spectral line is described. The instrument employs a liquid-crystal tunable Lyot-type spectral filter and an array detector that allows the full solar disk to be observed with a time cadence of minutes. We describe the telescope's optical and mechanical features and discuss computer interface and data-reduction procedures employed. Instrument performance during the initial year of operation of the telescope at its high-altitude site is summarized.

Tunable liquid-crystal filter for solar imaging at the He i 1083-nm line.

A Lyot-Ohman filter for imaging near the solar He i 1083-nm line is described. Fast and continuous spectral tunability is provided by nematic liquid crystals. This solid-state filter has a free spectral range of 2.35 nm and a spectral resolution of 0.135 nm at the operating wavelength of 1083 nm. A wide-fielded design was used for both static and electro-optic retarder elements, facilitating use in fast imaging systems. A first-light He i image of the Sun is presented.

Analysis of desmethylmethsuximide using high-performance liquid chromatography.

Analysis of desmethylmethsuximide by high-performance liquid chromatography (HPLC) is described. After adding an internal standard (IS), 200 microliters of plasma was buffered to pH 4.5 and extracted with dichloroethane. The organic solvent was then evaporated to dryness and the residue reconstituted in 100 microliters of mobile phase prior to injecting a 20 microliters aliquot onto a Hypersil 5 MOS column, which was eluted with acetonitrile/acetate buffer (pH 5.5) 36:64 vol/vol. Constituents were separated in approximately 8 min. Using this method, down to 1.0 mg/L of desmethylmethsuximide in plasma can be accurately determined. The method is suitable for therapeutic monitoring of desmethylmethsuximide in patient samples.

The analysis of clobazam and its metabolite desmethylclobazam by high-performance liquid chromatography.

The analysis of clobazam and its metabolite desmethylclobazam by high-performance liquid chromatography is described. After adding an internal standard 500 microliters of plasma is extracted under basic conditions into dichloroethane. The organic solvent is then evaporated to dryness and the residue reconstituted in 100 microliters of mobile phase prior to injecting an aliquot (30 microliters) onto a Hypersil 5 MOS column, which is eluted with acetonitrile/acetate buffer (pH 5.4) 40:60 vol/vol. The components are separated in approximately 12 min. Using this method, 15 micrograms L-1 of clobazam and 30 micrograms L-1 of desmethylclobazam can be detected. The method is suitable for the therapeutic monitoring of these two drugs in patient samples.

Clearance of phenylethylmalonamide during haemodialysis of a patient with renal failure.

Information is presented for the serum concentrations during haemodialysis of primidone, phenobarbitone, and phenylethylmalonamide (PEMA) in a patient with renal failure receiving chronic primidone therapy. The concentrations of drug and metabolites fell during haemodialysis, but PEMA concentrations were above normal at all times. The average renal clearance of PEMA during 6 h of dialysis was found to be 84.7 +/- 4.6 ml min-1.

Gas chromatographic analysis of phenylethylmalonamide in human plasma.

A method is described for the analysis of phenylethylmalonamide in human plasma. Analysis of plasma requires only 200 microliter of sample which is extracted with dichloroethane. After filtration and evaporation of the solvent the residue is reconstituted in 50 microliter of chloroform and 5 microliter are injected onto the gas chromatograph. The column used is a mixture of CDMS/WG11 coated on Chromosorb W HP 100-120 mesh. The method is suitable for use in single-dose pharmacokinetic studies.

Pharmacokinetics of phenylethylmalonamide (PEMA) in elderly men.

The pharmacokinetics of phenylethylmalonamide (PEMA) were studied in 6 elderly men after oral administration of a single 400 mg dose. Peak PEMA serum levels were obtained within 4 h of intake, half-life values ranged from 30.7-57.9 h in these elderly men. The elimination half-life was twice as long when compared to a study previously performed in young volunteers.

Phenylethylmalonamide serum levels in patients treated with primidone and the effects of other antiepileptic drugs.

Data are presented for the serum levels of 2-ethyl-2-phenylmalonamide (PEMA) in patients receiving anticonvulsant medication. Statistical analysis of these data indicates that the serum level of PEMA, which is a metabolite of primidone, is affected not only by the dose of primidone but also by the serum levels of other prescribed anticonvulsant drugs. In particular, phenobarbitone is shown to be a major perturbation upon the PEMA serum level.

Pharmacokinetics of phenylethylmalonamide (PEMA) in normal subjects and in patients treated with antiepileptic drugs.

The pharmacokinetics of phenylethylmalonamide (PEMA), a major metabolite of primidone, were investigated following administration of single oral doses (400 mg) to six normal subjects and six patients receiving chronic treatment with antiepileptic drugs. Peak serum PEMA levels were usually attained with 2-4 h after intake. The oral bioavailability estimated on the basis of the recovery of unchanged drug in the urine of normal subjects was at least 80%. Half-life values ranged from 17 to 25 h in normal subjects and from 10 to 23 h in the patients. No statistically significant difference in any of the calculated kinetic parameters could be found between the two groups. The data indicate that PEMA is readily absorbed from the gastrointestinal tract and that it is eliminated predominantly unchanged in the urine of man.

A method for predicting atmospheric aerosol scattering coefficients in the infrared.

A method for predicting scattering coefficients in the atmospheric windows from 1.0 micro to 15.0 micro is presented. The method avoids the assumptions that the index of refraction and the aerosol distribution are constants over the range of relative humidity values. Relative humidity is taken as the independent variable with the aerosol distribution and index of refraction dependent upon the value of the relative humidity. A two-component continental and maritime aerosol distribution is used. Although strictly applicable to the 1.0-15.0 micro wavelength region, the calculations are extended with a lesser degree of accuracy into the visible region so that comparisons with measured data may be made.

Infrared measurements of atmospheric transmission at sea level.

Atmospheric transmittance spectra from 0.56 micro to 10.7 micro obtained over a 25-km horizontal path at sea level, are presented. The sources were six 150-cm diam carbon are searchlights. A radiometrically calibrated spectrometer equipped with a NaCl prism and a thermocouple detector was used to record the spectral distribution of the radiation transmitted through the atmosphere. The transmittance spectra were obtained for values of precipitable water vapor ranging from 21.5 cm to 43.3 cm. From these spectra the selective transmittance of four atmospheric windows was measured. A plot of selective transmittance as a function of the square root of the precipitable water vapor for the four windows shows that the transmittance in these windows is well described by the statistical model of band absorption.

Near infrared atmospheric absorption over a 25-knm horizontal path at sea level.

Atmospheric absorption spectra obtained over a 25-km, horizontal, sea level path in the Cape Kennedy area are presented. Six 150-cm diam carbon are searchlights positioned from 11 m to 17 m above the ground were used as sources of continuous radiation. Solar spectra obtained from sea level are traced above the corresponding horizontal path spectra for comparison. The spectral region covered is 0.68 micro to 4.86 micro and the spectral resolution varies over this region from about 0.6 x 10(-4) micro to 60 x 10(-4) micro. The amount of water vapor in the path varied from 9 to 39 precipitable cm.