[Roentgenologic and nuclear medicine findings in alkaptonuric ochronosis]. / Röntgenologische und nuklearmedizinische Befunde bei der alkaptonurischen Ochronose.

In alkaptonuria, a recessively inherited disturbance of amino acid metabolism, deposits of oxydation products of homogentisinic acid result in the disease pattern of ochronosis. Due to the enhanced brittleness of the supporting and gliding tissue, ochronotic arthropathy develops at the vertebral column and later at the major joints with typical roentgenological changes especially in the intervertebral space and the intervertebral disk, as well as the adjacent vertebral bodies. The bone scintigram shows enhanced accumulation in the base and tectorial plates as well as in the adjacent sclerosing zones in the spongiosa of the affected vertebral bodies.

[Determination of pulmonary diffusing capacity during artificial ventilation (author's transl)]. / Bestimmung der pulmonalen Diffusionskapazität während Beatmung.

Pulmonary diffusing capacity may be determined by rebreathing techniques using various test gases. The errors caused by functional inhomogenities are smaller with the rebreathing method than those found in the single-breath technique. However, until now there have been some disadvantages to the clinical application of the rebreathing technique. In the present paper, a modification of the rebreathing technique suggested by Piiper, Scheid, Meyer and Adaro (1975 and 1976), in which pulmonary diffusing capacity for carbon monoxide, DCO(RB), is measured, has been applied to intubated and anesthetised patients. Measurements were performed in 39 surgical patients with healthy lungs during artificial ventilation and narcosis. Under these conditions all patients had a DCO(RB) greater than or equal to 75 ml/min . kPa (10 ml/min.torr). The coefficient of variation for duplicate measurements was +/- 4.2%. In the same patients DCO-single-breath-measurements, DCO(SB), were also made. There was a significant (p less than 0.0001) correlation between DCO(RB) in artificially ventilated, anaesthetised patients in a supine position and DCO(SB) for spontaneously breathing, awake patients in a sitting position. A linear regression analysis of the data showed the DCO(SB) was related to DCO(RB) in the following manner: DCO(SB) = 1.62DCO(RB) = 4.44 (ml/min.torr) (r = 0.71, n = 39). The mean value of DCO(RB) was 53.4% of the mean value of DCO(SB). This difference may be due to the combination of different techniques used and different conditions during the measurements (reduced FRC, difference in F1O2 etc.). The histogramm of the distribution of DCO(RB) had a similar form to that of DCO(SB). The modified method has a high reproducibility and can easily be performed as a bed-side test without disturbance to patients with an endotracheal tube.

Human placenta alpha-N-acetylglucosaminidase: purification, characterization and demonstration of multiple recognition forms.

alpha-N-Acetylglucosaminidase (EC 3.2.1.50) was purified from human placenta by a four-step procedure including ammonium sulfate precipitation, affinity chromatography with immobilized antibodies against urinary alpha-N-acetylglucosaminidase, gel chromatography and discontinuous gel electrophoresis with a 30% recovery and 26 300-fold purification. Immunological methods revealed the contamination with about 10% non-alpha-N-acetylglucosaminidase protein. Isoelectric focusing led to a distribution of activity between 4.3 and 6.5 with maxima at pH 5.1 and pH 5.7. After treatment with neuraminidase, alpha-N-acetylglucosaminidase activity assembled at pH 5.7. The multiple isoelectric forms were endocytosed with different rates by cultured human skin fibroblasts. Placenta alpha-N-acetylglucosaminidase has an apparent molecular weight of 304 000 and contains 23.4% carbohydrate consisting of glucose, galactose, mannose, hexosamines and neuraminic acid. Gel electrophoresis in the presence of 0.1% sodium dodecylsulfate separated placenta alpha-N-acetylglucosaminidase into subunits with molecular weights of 86 500 and 81 000. The activity towards various substrates, the kinetics of hydrolysis, the pH optimum and the stability of the catalytic activity were assayed.