Congenital arterial anomaly in the middle ear presenting as a glomus tumor.

A case of congenital agenesis of the cervical internal carotid artery with rerouting via the inferior tympanic artery and the embryonic hyoid artery to the horizontal internal carotid artery is presented. At otoscopy the anomaly simulated a glomus tumor. CT scan, by demonstration of the absence of the vertical portion of the carotid canal, the enlargement of the inferior tympanic canaliculus, and the soft tissue mass within the middle ear in continuity with the horizontal internal carotid artery, diagnosed the anomaly very accurately.

Resorption of the lateral maxillary incisor: assessment by CT.

Computed tomography of the maxillary alveolar arch was performed in three children with delayed eruption of one or both maxillary cuspids. Computed tomography demonstrated close contact between the ectopically localized and nonerupted canine and the lateral incisor. The lesion was unilateral in two patients and bilateral in one. In two patients resorption of the lateral incisor root was demonstrated. Moreover, CT permitted exact determination of the extent of the lesion by differentiating between superficial cementodentine resorption limited to the cementodentine (superficial resorption) and resorption extending into the pulpal canal (pulpal canal involvement).

[Amyloidosis of the stomach: presentation of a case]. / Amyloidosis van de maag: voorstelling van een geval.

We consider here a case presenting X-ray abnormalities in the stomach caused by amyloidosis: decreased distensibility of the stomach wall and absence of folds. These X-ray findings are non-specific. They can also be observed in cases of chronic gastritis and tumor infiltration.

Vanadium containing bromoperoxidase: An example of an oxidoreductase with high operational stability in aqueous and organic media.

The conversion is described of phenolsulphonephtalein (phenol red) to 3,3',5,5'-tetrabromophenolsulphonephthalein (bromophenol blue) by bromoper-oxidase from the brown alga Ascophyllum nodosum. This reaction provides a convenient assay for the detection of bromoperoxidase activity in vitro. Bromoperoxidase was shown to be stable under turnover conditions for three weeks at room temperature, catalyzing the bromination of phenol red into bromophenol blue. When stored at room temperature in organic sol vents such as acetone, methanol, ethanol [present up to 60% (v/v)], and 1-propanol [40% (v/v)], bromoperoxidase was stable for more than one month. As far as we know this is the first example of an oxidoreductase which displays such great stability. This enhances the applicability of the enzyme in organic synthesis.

Kinetics and stability of immobilized chicken liver xanthine dehydrogenase.

Xanthine dehydrogenase (EC 1.2.1.37) was isolated from chicken livers and immobilized by adsorption to a Sepharose derivative, prepared by reaction of n-octylamine with CNBr-activated Sepharose 4B. Using a crude preparation of enzyme for immobilization it was observed that relatively more activity was adsorbed than protein, but the yield of immobilized activity increased as a purer enzyme preparation was used. As more activity and protein were bound, relatively less immobilized activity was recovered. This effect was probably due to blocking of active xanthine dehydrogenase by protein impurities. The kinetics of free and immobilized xanthine dehydrogenase were studied in the pH range 7.5-9.1. The Km and V values estimated for free xanthine dehydrogenase increase as the pH increase; the K'm and V values for the immobilized enzyme go through a minimum at pH 8.1. By varying the amount of enzyme activity bound per unit volume of gel, it was shown that K'm is larger than Km are result of substrate diffusion limitation in the pores of the support material. Both free and immobilized xanthine dehydrogenase showed substrate activation at low concentrations (up to 2 microM xanthine). Immobilized xanthine dehydrogenase was more stable than the free enzyme during storage in the temperature range of 4-50 degrees C. The operational stability of immobilized xanthine dehydrogenase at 30 degrees C was two orders of magnitude smaller than the storage stability, t 1/2 was 9 and 800 hr, respectively. The operational stability was, however, better than than of immobilized milk xanthine oxidase (t 1/2 = 1 hr). In addition, the amount of product formed per unit initial activity in one half-life, was higher for immobilized xanthine dehydrogenase than for immobilized xanthine oxidase. Unless immobilized milk xanthine oxidase can be considerable stabilized, immobilized chicken liver xanthine dehydrogenase is more promising for application in organic synthesis.