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Biomedical subjects

R Hurwitz

Publications and source records attributed to R Hurwitz.

68 records · Page 4Linked to original sources

Intestinal enzymes: indicators of proliferation and differentiation in the jejunum.

Some intestinal enZymes were assayed which were related to: (i) Cellular proliferation, for example, aspartate carbamoyltransferase, thymidine kinase, uridine kinase, and dihydroorotase; (ii) cellular differentiation, for example, lactase, invertase, maltase, alkaline phosphatase, and dipeptidase; and (iii) lysosomes, for example, beta-glucuronidase, acid beta-galactosidase, and acid phosphatase. These enzymatic determinations can be used to distinguish the crypt from the villus during healthy or diseased states.

Animals↗

Effect of colchicine on intestinal disaccharidases: correlation with biochemical aspects of cellular renewal.

There was a significant depression of the activities of intestinal lactase, invertase, and alkaline phosphatase in rats given drinking water containing 2.5 mg of colchicine per 100 ml. Activities of intestinal maltase, aspartate transcarbamylase, and dihydroorotase were not affected by the drug. Injection of colchicine (1 mg/kg) caused depression of intestinal invertase activity within 8 hr. Investigation of the effect of colchicine on the disaccharides in vitro demonstrated that invertase and maltase were not affected by concentrations up to 125 mg/100 ml. Intestinal lactase was inhibited by concentrations exceeding 5 mg/100 ml. Calculation of the concentration of colchicine present in the intestine, after a single injection, indicated that the in vivo effect of colchicine was not due to simple enzyme inhibition. Histological examination showed an increase in crypt cells but no decrease in the length of the villi. Cellular migration along the villi, as well as activity of uridine kinase in intestinal mucosa, was increased in colchicine-treated rats. It was concluded that colchicine did not depress intestinal invertase, lactase, and alkaline phosphatase by decreasing cellular renewal, but rather it exerted its effect directly on the differentiated cells of the villus.

Alkaline Phosphatase↗

Assessment of coronary artery patency after stent placement using magnetic resonance angiography.

The ability to noninvasively assess the patency of coronary stents would represent a significant advance. We evaluated the safety and ability of two-dimensional coronary MR angiography in imaging stents and suggesting patency. Coronary MR angiography of 26 coronary stents (Palmaz-Schatz) was performed in 16 patients 39 to 73 years of age. Studies were performed between 2 and 4 months after stent placement. All patients were symptom free at the time of imaging. Coronary MR angiography was performed with a commercial 1.5-T MR imager using an electrocardiographically gated pulse sequence with breath-holding. Images were obtained in mid-diastole with and without fat suppression. Image artifacts caused by the metal in the stents were clearly visualized in all 26 stents (100% sensitivity for stent detection). Arterial flow signal was seen in the coronary artery or graft distal to the stent in 25 of 26 cases (96%). All patients, except for the one in which distal flow could not be seen, remained symptom free for >2 years. The distribution of stent locations was as follows: 10 in the right coronary artery (RCA), 10 in the left anterior descending coronary artery (LAD), 2 in the left circumflex coronary artery, and 4 in saphenous vein grafts (SVGs) to RCA. One patient had 2 RCA and 2 LAD stents, one had 3 RCA and 1 LAD stents, one had 3 SVG stents, and two had double RCA stents. Coronary MR angiography is safe for noninvasive imaging of coronary stents, and in the proper clinical setting, it can be used to help suggest patency.

Adult↗

Myocardial infarction late after Mustard procedure.

This case report discusses a young man with d-transposition of the great arteries who suffered three myocardial infarctions late after his Mustard procedure. The etiology was found to be a coronary embolism, with a mural thrombus in the systemic ventricle as the probable nidus. The risk factors of coronary embolism are discussed, and it is concluded that Mustard patients are at risk for coronary embolization and myocardial infarction, which can be a cause of sudden death.

Adolescent↗

Persistent eustachian valves in infants: course and management in symptomatic patients.

Although commonly found on echocardiograms, persistent Eustachian valves rarely result in clinical symptoms in newborns and infants without other significant structural heart disease. Previous reports have suggested that such patients require surgical treatment. The goal of this study is to delineate better the clinical course in infants presenting with symptoms that are a result of persistent Eustachian valves. A review of all patients with symptoms attributed to persistent Eustachian valves over a 10-year period at Riley Hospital for Children showed 3 of 4 patients improved, with eventual resolution of symptoms, with conservative management alone. This suggests that, contrary to previous reports, clinical observation may be warranted in many of these infants.

Cor Triatriatum↗

Monitoring intravenous fat emulsions in neonates with the fatty acid/serum albumin molar ratio.

Weekly determinations of the fatty acid/albumin molar ratio (FA/SA) were obtained 136 times on 50 neonates (birthweight range, 675-4300 grams; median, 1360 grams) to determine if our use of intravenous fat (IVF) was putting these newborns at risk for kernicterus. The FA/SA was measured using a convenient spectrophotometric technique which we have previously described (Berde CB, Kerner JA, Johnson JD: Clin Chem 26:1173-1177, 1980). Twenty-nine infants received IVF with doses from 0.5 to 3.3 gram/kilogram/day (mean 1.5 gram/kilogram/day), given over 24 hours whenever possible, most commonly begun in the second week of life when the bilirubin level was less than one half of the potential exchange level. Twenty-one infants received no IVF. Previous studies show that fatty acids do not begin to displace bilirubin from albumin until the FA/SA is greater than 6 in vivo, and greater than 4 in vitro. All our infants had safe values with mean FA/SA values of approximately 1.0. Continuous IVF as we administer it does not place neonates at risk for kernicterus. Centers administering IVF in the first week of life or by bolus should consider close monitoring of their infants with the FA/SA.

Fat Emulsions, Intravenous↗