Biomedical subjects
Publications and source records attributed to A Riva.
Fluorescein-labelled glycosaminoglycans (F-GAG) were absorbed by the rat intestinal tract when administered in an anhydrous suspension consisting of vegetable fats and sodium taurocholate. A statistically significant regression between plasma levels of F-GAG and plasma lipoprotein lipase activities was found.
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While the use of the 24 hour Holter monitoring for the detection of the cardiac arrhythmias and conduction disturbances is well established, its applicability to the monitoring of the ST segment and T wave for the detection of myocardial ischemia is controversial. For these reasons the Holter monitoring is mainly confined to the detection of cadiac arrhythmias and is used in those centers where computer facilities are available. We proposed to record the electrocardiographic tape replayed at 60 times the real time on a direct recording ultraviolet oscillograph running at low speed obtaining a fast compact analogue representation of the Holter recording where the 24 hour Holter recording is compressed into cm 480 of paper. The analogue compact representation described allows an easy detection of the transient displacement of the ST segment and/or changes in the T wave amplitude and direction and/or QRS pattern all due to myocardial ischemia without the use of any expensive computer facilities.
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A cytochemical study on the localization of the enzymes glucose-6-phosphate dehydrogenase, sorbitol dehydrogenase, and alkaline phosphatase was carried out in human ampullary glands. Although the former two enzymes showed a marked reactivity, alkaline phosphatase was absent from epithelial cells. On the basis of these results it is concluded that, as in the human seminal vesicle, in the ampullary gland fructose is probably secreted via the oxidative mechanism proposed by Hers (Le Metabolisme du Fructose. Bruxelles, Arscia, 1957).
The localization of endogenous peroxidase was studied in human parotid and submandibular glands using the medium of Strum & Karnovsky either at pH 7 or at pH 8.3, after a short fixation of the tissues with a low concentration of glutaraldehyde. At pH 7 reaction product was found in seromucous cells of both glands in the cisternae of the rough endoplasmic reticulum, in the elements of the Golgi apparatus, and in secretory products. However, while in the parotid gland all secretory granules showed peroxidase activity, in the submandibular gland some of the granules were left unstained. At pH 8.3 the pattern of reactivity was practically unchanged in the submandibular gland, whereas the amount of precipitate noticeable in the secretory granules of the parotid gland was greatly reduced. The method of Novikoff et al. for catalase revealed the presence of a number of small bodies having in the characteristics of peroxisomes. Acid phosphatase was not demonstrable in the secretory granules of either parotid or submandibular glands. The lead precipitate indicating enzyme activity was observed only in lysosomes and, occasionally, in the elements of the Golgi apparatus of some sermucous cells.
Serum digitalis concentration was measured radioimmunologically on 1006 patients in the period from 1974-1976. The serum levels were correlated with the clinical signs of digitalis toxicity and the indications for determination of the serum digoxin concentration were established. Clinical signs of toxicity appear at a serum level of digoxin above 2.5 ng/ml. Therapeutic limits (range) are most influenced by individual factors. Serum digoxin determination is especially necessary in patients with renal failure and in undisciplined patients with erratic digitalis intake. It is a useful aid in controlling the course of digitalis intoxication, in "low dosage" digitalization and in the case of possible drug interactions.
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An intralobular duct of a human parotid gland has two parts, an intercalated part and a striated part. Intercalated ducts are lined with low cuboidal cells endowed with scanty cytoplasmic organelles. Striated ducts are lined with columnar cells rich in mitochondria and glycogen particles, and are characterized by extensive infoldings of the basal plasma membrane. The apical cytoplasm of the cells of the striated ducts shows a number of membrane-bound granules having a diameter of about 0-15 mum. These granules contain material of varying electron density which does not react with silver or with the histochemical reagents employed in the present study. Thus, on the basis of their small size and histochemical characteristics, they are distinct from the large and dense secretory granules observed in the so-called granular striated ducts of some animals. In addition, cells of striated ducts contain lysosomes, peroxisomes, and large lipoid bodies which give histochemical reactions typical of lipofuscins. Bodies of myoepithelial cells have been observed only in intercalated ducts. Their processes, however, extend into the proximal parts of striated ducts.
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