J.C. Crawhall

Cysteamine, penicillamine, glutathione, and their derivatives analyzed by automated ion exchange column chromatography

Abstract Amino thiols have been measured by automatic amino acid analysis after blockage of the SH group by reagents such as iodoacetic acid, iodoacetamide, and N -ethylmaleimide. Elution characteristics for these derivatives for penicillamine, cysteamine, and glutathione are described. Cysteamine has been measured in rat plasma after oral administration (stomach tube). It had a biological half-life in rat plasma of 1.7 hr. Glutathione as its iodoacetamide derivative can be measured simultaneously with cystine in extracts of fibroblast cells of patients with cystinosis. This will be valuable for investigations of the metabolic defect in cystinosis, but the technique has certain difficulties which interfere with the accuracy of the analysis.

Fabry's Disease: Differentiation between Two Forms of α-Galactosidase by Myoinositol

Myoinositol appears to be a competitive inhibitor of α-galactosidase activity in fibroblasts of normal human skin but not of the residual α-galactosidase activity of fibroblasts obtained from patients with Fabrys disease. It is suggested that normal fibroblasts contain two α-galactosidases, only one of which is present in cells from patients with Fabrys disease, and that these enzymes can be distinguished by their different Michaelis constants, rates of heat inactivation, and responses to the inhibitor myoinositol.

A rapid method for the analysis of urinary methylmalonic acid

Abstract A method for the determination of urinary methylmalonic acid, applicable on a routine clinical basis, is described. The method is based on the isolation of a mono-tooligo-carboxylic acid fraction from urine by a series of ether extractions and the subsequent gas Chromatographie analysis of these acids as their trimethylsilyl esters and ethers. The method is simple, rapid, and quantitative, and involves no hazardous chemistry.

A rapid gas chromatographic method for the quantitation of volatile fatty acids in urine : Propionic acid excretion in vitamin B12 deficiency

Abstract A method for the isolation and quantitation of urinary volatile fatty acids is described. The method involves a simple clean-up procedure to eliminate neutral substances (e.g. ketones) and subsequent gas chromatographic analysis of the free acids. Analysis time is shorter, recoveries are excellent, and separation of the acids has been improved over previously reported methods. The method is used to study propionic acid excretion in vitamin B12 deficient patients.

Reduction of disulfides with sodium and potassium borohydrides and its application to urinary disulfides.

Abstract The reduction of various naturally occurring disulfides with sodium and potassium borohydride is reported. Both these hydrides were poor reducing agents at room temperature but at a higher temperature (50°) the reduction was complete within 30 min. Sterically hindered disulfides, penicillamine-cysteine-mixed disulfide and penicillamine disulfide, were only partially reduced; the former up to 50% and the latter up to 10–12%. At room temperature a much better yield of free thiols was obtained from Sterically hindered disulfides in the presence of Cu2+ or Fe2+. The sodium borohydride method was used to measure urinary disulfides in cystinuric patients, their parents, and control subjects; it was also used in a patient with β-mercaptolactate-cysteine disulfideuria. This method was not successful when patients were receiving penicillamine therapy because of the partial reduction of penicillamine-cysteine-mixed disulfide.

Case Report: Catecholamine-Secreting Paraganglioma of Glomus Jugulare Region

ABSTRACT A 43-year-old woman had clinical and biochemical evidence of a secreting paraganglioma of the glomus jugulare region. Catecholamine secretion was exacerbated during embolization of the tumor before surgery and resulted in a life-threatening vasomotor attack. Preoperatively, pharmacologic blockade of excessive catecholamine secretion with prazocin controlled her blood pressure, tachycardia, and symptoms. The tumor was resected and its catecholamine content measured. This case is reported to stress the importance of adequate preoperative assessment of patients with paragangliomas of the head and neck. The extreme rarity of catecholamine-secreting tumors of this region should not lead us to underestimate the morbidity and mortality of such patients undergoing surgery or any other invasive procedure whether the diagnosis is confirmed or only suspected.

Separation and quantitation of oxypurines by isocratic high-pressure liquid chromatography: Application to xanthinuria and the Lesch-Nyhan syndrome

An isocratic HPLC technique has been developed for the separation and measurement of urine and plasma oxypurines in a patient with xanthinuria. The case history and laboratory data are presented. Xanthine excretion was 172 mg/g creatinine and hypoxanthine was 45 mg/g creatinine. Uric acid was too small to be measured but uricase determination showed only 3 mg/24 hr. Serum oxypurine analysis showed hypoxanthine 0.87 mg/dl and xanthine 0.35 mg/dl. Uric acid was not seen in this patients serum but could be readily measured in normal control subjects. The technique can also be used to separate nucleotides from purine bases, and we have demonstrated its application to the measurement of erythrocyte hypoxanthine guanine phosphoribosyl transferase and adenine phosphoribosyl transferase in a kindred associated with the Lesch-Nyhan syndrome.

Elevation of serum creatine kinase in severe hypokalemic hyperaldosteronism

The association between hypokalemia and increased serum creatine kinase has been investigated. Two patients were found who had severe hypokalemic hyperaldosteronism who had elevation of serum creatine kinase activity. The CPK activity returned to normal values after fluid and potassium replacement. In a prospective study of 129 patients with hypokalemia which did not include any patients with hyperaldosteronism, 12 were found to have increased CPK activity but each of these had some other severe disease process which could account for the increased CPK. Three other patients with K+ (2.2 MEq/1 did not have increased CPK. It is concluded that patients with severe hypokalemia such as that occurring in hyperaldosteronism with muscle weakness may have elevated CPK directly related to their hypokalemia. In other patients with hypokalemia, 10% may have increased CPK but this is related to other disease processes.

Uric acid estimation: a comparison of the manual uricase-UV and the phosphotungstate auto-analyzer methods

1. Uric acid estimations by the uricase-UV and the autoanalyzer colorimetric procedures were compared. 2. At all levels of serum uric acid concentration measured, results with the uricase-UV method were significantly lower than those with the phosphotungstate method. 3. The data indicate that the critical uric acid level (measured by the autoanalyzer) at which allopurinol, uricosuric, and other agents are instituted should be decreased approximately 10 per cent when determinations are done by the uricase method.

Gas chromatographic estimation of hydroxyproline

Abstract A method for the determination of hydroxyproline is described. The imino acid is cleanly separated from other urinary metabolites on an ion-exchanger. The eluant containing hydroxyproline is flash evaporated and chromatographed as its trimethylsilyl (TMS) ester. The method avoids several potential sources of interference found in currently available methods. It is very specific for hydroxyproline and recovery is satisfactory.