Column elution and concentration of volatile compounds in biological fluids

A new solvent elution method is described for the isolation and concentration of volatile metabolites in biological fluids. The procedure involves elution of the sample with a solvent through a micro-column of an adsorbent into glass-wool and evaporation of the excess solvent in a stream of helium at room temperature. The volatiles are revocered by subsequent heat desorption into a chromatogrpaphic system. Both elution and evaporation are made in a single step using a novel sampling device. Since the technique is based on liquid-solid adsorption chromatography, the adsorbent-solvent system which gives the maximum yield of volatile constituents was studied. The method is simple, highly efficient and reproducible, requiring only small volumes of biological fluids (less than 100 mul).

Interaction of adrenergic antagonists with prostaglandin E2 and tetrahydrocannabinol in the eye

Both alpha- and beta-adrenergic antagonists have been utilized in an atempt to discern the site of action of prostaglandin (PG) and tetrahydrocannabinol (THC) in the eye. Both alpha- and beta-adrenergic antagonists (alpha-antagonists, phentolamine and phenoxybenzamine; beta-antagonists, propranolol and sotalol) cuased a dose-dependent reduction in intraocular pressure and blood pressure and increased total outflow facility. The results are consistent with the concept that both alpha- and beta-adrenergic receptors are present in the anterior uvea and that vasomotor tone is essential to the maintenance of normal intraocular pressure. No antagonist reduced the PG-induced elevation of intraocular pressure unless the blood pressure was severely lowered. All antagonists inhibit the normal PG-induced increase in total outflow facility, indicating that these agents protect the blood-aqueous barrier from breakdown without altering the vasodilatory response to PG. All antagonists reduced the fall in intraocular pressure produced by THC by approximately 50 per cent, except for sotalol which completely abolished the intraocular pressure fall. Only the alpha-adrenergic antagonists prevented the THC-induced increase in total outflow facility. The results indicate that true outflow facility may well be regulated exclusively by alpha-receptors. The data are consistent with the effect of THC being primarily a vasodilation of the efferent blood vessels of the anterior uvea. The partial inhibition by alpha-adrenergic antagonists may also suggest a lesser role of THC on the afferent vessels.

Gas-chromatographic and mass-spectrometric detection of low-molecular-weight aliphatic alcohols in urine of normal individuals and patients with diabetes mellitus

We studied the aliphatic alcohols in 100 urines from 25 patients with diabetes mellitus under treatment with insulin, oral antidiabetic medication, or special diet. The procedure involves adsorption of the low-molecular-weight urinary metabolites on a porous polymer of 2,6-diphenyl-p-phenylene oxide (Tenax GC), gas-chromatographic separation, mass spectrometric identification, and mass fragmentographic representation of the primary alcohols by a computer. The concentrations of ethanol, n-propanol, isobutanol, n-butanol, and isopentanol are increased as compared with urine from normal persons.

Pattern of ocular response to topical and systemic prostaglandin

Changes in both intraocular pressure and total outflow facility were determined after short- and long-term infusion and topical application of prostaglandin E1 and E2. The intraocular pressure with both routes of administration increased within 15 minutes by 10 to 15 mm. Hg; long-term infusion caused the intraocular pressure to be elevated for a longer time, although a fall in intraocualr pressure occurred despite continued infusion. Total outflow facility did not increase until 30 minutes after initiation of treatment and thereafter increased further with time, irrespective of the route of drug application. The initial increase in intraocular pressure is suggested to be the result of vascular changes, namely an increase in the leakiness of the iris vessels and the capillary pressure of the ciliary body vessels caused by the vasodilatory actions of prostaglandins.

Mode of inhibition of diphtheria toxin by ammonium chloride

Kim, K. (University of Washington, Seattle), and N. B. Groman. Mode of inhibition of diphtheria toxin by ammonium chloride. J. Bacteriol. 90:1557-1562. 1965.-The inhibition of diphtheria toxin by ammonium salts was independent of toxin concentration over a 100-fold range of toxin. Inhibition by minimal concentrations of ammonium chloride was abolished by lowering the pH, indicating that free ammonia is the active form of inhibitor. A single addition of ammonium chloride inhibited toxin for a limited period of time, but periodic readdition of the ammonium salt was required to sustain inhibition indefinitely in the absence of antitoxin. Toxin was not destroyed and its adsorption occurred equally well in the presence or absence of ammonium chloride. Preadsorbed toxin was also effectively inhibited by the addition of ammonium chloride. Inhibited toxin remained accessible to antitoxin neutralization. Attempts to reverse ammonia inhibition by the addition of succinate or reduced nicotinamide adenine dinucleotide were unsuccessful. Attempts to inhibit toxin by interfering with active transport were also unsuccessful.

In vitro inhibition of diphtheria toxin action by ammonium salts and amines

Kim, K. (University of Washington, Seattle), and N. B. Groman. In vitro inhibition of diphtheria toxin action by ammonium salts and amines. J. Bacteriol. 90:1552-1556. 1965.-An inhibitor for diphtheria toxin action on HeLa cells was demonstrated in the growth supernatant fractions of both toxinogenic and nontoxinogenic strains of Corynebacterium diphtheriae and in the Mueller and Miller medium in which these organisms were grown. The inhibitor in the growth supernatant fractions of the nontoxinogenic strain was dialyzable, stable to autoclaving, and stable on storage in the refrigerator for a period of many months, but was destroyed by ashing. When the components of Mueller and Miller medium were analyzed, only the Casamino Acids proved inhibitory. Further study with artificial mixtures of amino acids revealed that glutamine alone inhibited toxin. It was subsequently shown that ammonium salts and the aliphatic amines, glycamine and prolamine, could also function as inhibitors. Histamine and 16 amino acids tested individually were ineffective. The effectiveness of the amines and the ineffectiveness of sodium or potassium ions indicates that there is a specific requirement for inhibition.