Sorbitol and other polyols in lens, adipose tissue and urine in diabetes mellitus.

Sugars and polyols (glucose, fructose, sorbitol, inositol and pentitols) have been measured in urine, adipose tissue and lens in groups of diabetic and non-diabetic patients. The daily excretions of glucose, sorbitol and inositol were raised in the diabetics. There was a linear relation between 24 hour urinary excretion of glucose and hexitols (r = +0.87, p less than 0.001). In lens of diabetics there was an increase in glucose concentration, but not of fructose, sorbitol or inositol. Compounds readily detected in adipose tissue were inositol and glucose; in addition an unidentified carbohydrate was detected in adipose tissue that related to the concentration of tissue glucose. These results are discussed in relation to the possibility that tissue accumulation of polyols could be responsible for the secondary complications of diabetes such as cataracts.     

A simple automated method for the fluorometric titration of calcium in biological fluids,.

A new automatic device has been developed for the determination of the calcium content in biological fluids. The method is based on a fluorometric titration technique, in which calcium is titrated with ethyleneglycolbis-(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA). The end-point of the titration is indicated by quenching of the fluorescence of a calcium-calcein complex, in which calcein is the fluorescein-complexone indicator. To obtain proper results we found it necessary to use a 1 molar potassium hydroxide solution as titration medium. The results are printed out directly in concentration units (mmol/l). In order to carry out these determinations, several electronic and mechanical devices, including a sample-changer, titration cabinet with built-in fluorometer, control unit and electron titrator, were developed. Together they form the new calcium automatic device of which several qualitites such as precision, recovery and correlation have been studied. The disturbing influence of bilirubin has been minimized by using an excitation wavelength of 492 nm, at which there is nearly no absorption by bilirubin. At a concentration of bilirubin of as much as 500 micronmol/l, the recovery of calcium is still about 96%.     

Physico-chemical and immunological properties of acid alpha-glucosidase from various human tissues in relation to glycogenosis type II (Pompe's disease).

The physico-chemical and immunological properties of acid alpha-glucosidase from various human tissues have been studied. Heat stability of acid alpha-glucosidase from heart, liver and skeletal muscle is identical, but for kidney some different results are obtained. Identical isoelectrofocussing patterns are found for heart, liver and skeletal muscle. Furthermore, the effect of antiserum against human liver acid alpha-glucosidase on the activity of acid alpha-glucosidase from various tissues is studied. The results are discussed in relation to glycogenosis type II (Pompe's disease).     

Plasma lysozyme level and reticuloendothelial system function in human liver disease

Plasma lysozyme levels have been reported to reflect the functional status of the reticuloendothelial system (RES). We measured plasma lysozyme levels in 22 patients with acute hepatitis and 21 patients with cirrhosis and a mesocaval shunt. In 17 of these patients RES function was assessed by measuring the disappearance rate (t/2) of radio-labelled sulphur colloid. In acute hepatitis plasma lysozyme levels and colloid t/2 were significantly lower than in healthy controls and cirrhotics. In the acute hepatitis patients, the plasma lysozyme levels rose significantly two weeks after admission as the hepatitis improved. The colloid t/2 of the 17 patients with liver disease was significantly correlated with the plasma lysozyme level (r = +0.66, p = 0.005).These results suggest that in human liver disease, in comparison with animal experiments, plasma lysozyme is dependent on RES functional status in the sense that a more active RES will result in a lower lysozyme level.     

International survey of the radioimmunological measurement of serum reverse triiodothyronine

An international survey was conducted to study the performance of the radio immunoassay of serum reverse triiodothyronine (rT₃). Eight laboratories were provided with 10 serum samples containing several concentrations of rT₃ and thyroxine (T₄). Each laboratory also obtained the same batch of pure rT₃. T₄ and rT₃ were measured by all participants in these samples. Half of the investigators routinely correct their data for T₄ cross-reactivity. The results demonstrate that the performance of the rT₃ radioimmunoassay is, on the average, satisfactory as judged from recovery experiments. Serum T₄ influences the rT₃ measurement to a lesser extent in the laboratories where corrections are performed compared with the others. Simple correction methods appear to fail, however, as the effect of a certain T₄ concentration was found to vary with the rT₃ level in the sample.     

Separation of human alpha-amylase isozymes by electro-focusing and their immunological properties.

Human alpha-amylase (alpha-1,4-glucan-4-glucanohydrolase, EC 3.2.1.1) was separated by electrofocusing. The amylases in serum and urine were seperated into two major isozymes with isoelectric points of pH 6.4-6.5 and pH 6.9-7.0, respectively, and one minor isozyme with an isoelectric point of pH 5.9. The amylases in saliva were separated into one major isozyme with an isoelectric point of pH 6.5 and two minor isozymes with isoelectric points of pH 6.0 and 6.9. The amylases in pancreatic juice gave one major peak at pH 7.0 and two minor peaks at pH 6.0 and pH 6.5. Repeated electrofocusing of each isozyme have only a single peak with a constant isoelectric point. The antigenicites of these three isozymes were also investigated using antisera to rat pancreatic and parotid amylases.     

Convenient immunofixation electrophoresis on cellulose acetate membrane.

Applying polyspecific antiserum onto cellulose acetate membrane after electrophoretic separation can result in a simultaneous fixation of multiple antigens as discrete bands with a resolving power of at least 30 ng protein per band.