Arthroscopic debridement of the arthritic knee.

Arthroscopic debridement was carried out in 49 knees of 44 patients. These patients, who had a primary diagnosis of arthritis, were older than 50 years of age. Two-thirds had roentgenographic evidence of severe arthritis. Age, weight, compartment location of arthritis, and presurgical range of motion did not affect surgical results. Symptoms of long duration, arthritic severity as evidenced by roentgenograms, and malalignment predicted poor results. Conversely, shorter duration of symptoms, mechanical symptoms, mild to moderate roentgenographic changes, and crystal deposition correlated with improved results. Surgery offered no benefit for 39% of the patients. Another 9% had temporary improvement, averaging 15 months, but were judged failures at the final follow-up examination. Good or excellent results were achieved in 52% of the patients and maintained through the final follow-up examination in 40% of the patients. Of these, two-thirds had no visible deterioration within a 33-month average follow-up period.

Standardization by reference methods: a German viewpoint.

The problems of applying optimized as well as standardized methods to the determination of enzyme activities in modern clinical laboratories are described. The failure of the so-called 'New Concept of Reference Method Values' in the quality assessment of enzyme assays is evidenced, and the advantages of standardized methods rather than only standard materials is demonstrated. Finally, the great similarities among European national recommended methods for enzyme assay is emphasized by a comparison of results obtained in estimating 5 enzymes.

Glutamate dehydrogenase: biochemical and clinical aspects of an interesting enzyme.

The molecular properties and possible metabolic functions of glutamate dehydrogenase (GLDH-EC 1.4.1.3) are described. The distribution of this enzyme in the body and particularly in the liver are outlined. The significance of these properties for GLDH release into the extracellular space, for the distribution and elimination of the enzyme and, foremost, for the assay of GLDH as a diagnostic indicator of hepatic and biliary disease are shown. Analytical methods are reviewed.

Amygdalin toxicity studies in rats predict chronic cyanide poisoning in humans.

Significant amounts of cyanide are released when amygdalin (Laetrile), a cyanogenic glycoside, is given orally or intravenously to rats. The amount of cyanide liberated following oral administration is dependent in part on the bacterial flora of the gut and can be suppressed by antibiotic pretreatment of the animals. Bacteria from human feces likewise hydrolyze amygdalin with release of cyanide. Humans taking amygdalin orally in the hope of preventing cancer are likely to be exposed to levels of cyanide in excess of that associated with the development of tropical ataxic neuropathy in people of underdeveloped countries where food containing cyanogenic glycosides is a staple part of the diet.

Laetrile toxicity studies in dogs.

Dogs were fed laetrile and fresh, sweet almonds under various conditions. The doses of laetrile were similar to those prescribed for patients with cancer and ranged on a basis of gram to square meter from an equivalent of the oral dose for man to five times this dose. Six of the ten dogs died of cyanide poisoning. One dog recovered, and three dogs, at the time of sacrifice, demonstrated various levels of neurologic impairment, ranging from difficulty in walking to coma. These studies demonstrate that oral laetrile is highly toxic when taken with some common table foods. We predict that there will be an increased incidence of cyanide poisoning in man as laetrile becomes more readily available.