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Biomedical subjects

J N Isenberg

Publications and source records attributed to J N Isenberg.

33 records · Page 2Linked to original sources
PubMed1977

Gallbladder disease in cystic fibrosis.

In 84 consecutive patients with cystic fibrosis, oral cholecystography was abnormal in 39 (46.4%). The incidence of abnormal cholecystograms increased with patient age. The 26 patients with a nonvisualized gallbladder following double-dosage oral cholecystography were evaluated with intravenous cholangiography; 19 (70.3%) of these were abnormal. Ten patients were found to have calculi, an incidence of 11.9%. Awareness of the high incidence of cholecystographic abnormalities and calculi should be helpful in the evaluation of patients with cystic fibrosis, particularly since symptoms of abdominal pain are frequent in such patients and may lead to radiographic investigations.

Adolescent↗
PubMed1977

The infant and hepatitis B virus infection.

HBV has been shown to be responsible for a broad spectrum of disease in infants although most are asymptomatic carriers with mild transaminase elevation and unresolved hepatitis on liver biopsy. Maternal-infant transmission is responsible for most infections. Blood product infusion should become less significant. Acute maternal hepatitis in the perinatal period results in asymptomatic infant infections at rates far exceeding transmission from asymptomatic carrier mothers. Carrier mothers with the e-antigen or HBV-associated DNA polymerase transmit infection more readily than do carrier mothers without these HBV markers. The presence of maternal anti-e may be protective. Intrapartum and postpartum transmission occurs more often than transplacental infection. For this reason attempts at prophylaxis with immune serum globulin administered in the newborn period should be further evaluated.

Female↗
PubMed1976

Immunodeficiency, xanthomas and obstructive liver disease.

Chronic obstructive liver disease and secondary hyperlipidemia developed in an immunodeficient boy. Sequential addition of cholestyramine and phenobarbital to his medical regimen, following an initial response to bile drainage, resulted in the disappearance of xanthomas and pruritus, and the restoration of normal serum concentrations of lipids and bile acids. This improvement may result from shifting the bile acid pool from the peripheral blood compartment to the enterohepatic circulation.

Bile Acids and Salts↗
PubMed1976

Aspartylglucosaminuria: unique biochemical and ultrastructural characteristics.

The observation of vacuolated lymphocytes in a coarsely featured two year old female with hepatosplenomegaly, mitral insufficiency, and mild psychomotor retardation led to the first diagnosed case of aspartylglucosaminuria in the United States. Although physical characteristics and bone roentgenograms were consistent with a mucopolysaccharide disorder, analysis of the urine showed no mucopolysaccharide elevation. The chromatographic, enzymatic, and ultrastructural studies confirming the diagnosis are presented.

Amidohydrolases↗
PubMed1976

The glycoprotein-degrading potential of peripheral leukocytes in cystic fibrosis.

In this study, the potential problems and discrepancies in cill culture techniques were avoided by isolating leukocytes from the peripheral blood of patients with cystic fibrosis and healthy human volunteers and preparing homogenates to determine the specific activities of 5 lysosomal enzymes involved in the degradation of glycoproteins. Four lysosomal hydrolases involved in the breakdown of the carbohydrate side chain were assayed using artificial substrates. The fifth enzyme, aspartylglucosamine amido hydrolase, which cleaves the linkage between this side chain and the peptide backbone, was assayed with natural substrate. No differences in enzyme activities between the 2 leukocyte sources were observed. Because no enzyme activities were deficient and no compensatory increases were noted, we concluded that the thick, glycoprotein-rich, exocrine secretions in cystic fibrosis cannot be attributed to a defect in their catabolism.

Acetylglucosaminidase↗
PubMed1976

Clinical observations on the biliary system in cystic fibrosis.

The biliary tree of 66 patients with cystic fibrosis was examined by conventional roentgenographic methods. Forty-five per cent of the oral cholecystograms were judged abnormal by our criteria. A study was considered abnormal if there was no visualization or if there was visualization of a microgallbladder or structural abnormality including marginal irregularities, septate gallbladder or cholelithiasis. Intravenous cholangiography was used to further study the 22 patients who did not visualize on the oral study. Again, anatomic abnormalities were prevalent but six patients in this group had normal appearing gallbladders. Abdominal pain, a frequent symptom in cystic fibrosis, was not associated with roentgenographic abnormality. No correlation was seen between the external biliary tree abnormalities and multifocal biliary cirrhosis which was present in 40% of these patients. Further, no correlation was seen between serum gamma glutamyl transpeptidase levels and either of these lesions.

Adolescent↗
PubMed1975

Aspartylglucosaminuria: psychomotor retardation masquerading as a mucopolysaccharidosis.

A 5-year-old girl with coarse facies, visceromegaly, and vacuolated lymphocytes is presented as the first case of aspartylglucosaminuria diagnosed in this country. This metabolic defect in glycoprotein catabolism can be clinically confused with other storage diseases such as the mucopolysaccharidoses and mucolipidoses. It is not diagnosed by routine laboratory screening methods. Special studies are required to confirm the diagnosis, but a thin-layer chromatography method for screening urine is presented for use when the diagnosis is suspected. The developmental potential in this inborn error of metabolism is documented.

Amidohydrolases↗
PubMed1975

The metabolism of 3alpha, 7alpha, 12alpha-trihydorxy-5beta-cholestan-26-oic acid in two siblings with cholestasis due to intrahepatic bile duct anomalies. An apparent inborn error of cholic acid synthesis.

Studies were carried out in a family in which two children with cholestasis due to intrahepatic bile duct anomalies were shown to have increased amounts of the cholic acid precursor, 3alpha, 7alpha, 12alpha-trihydorxy-5beta-cholestan-26-oic acid (THCA). The metabolism of THCA was studied in one of these patients after an intravenous injection of (3H)THCA, and the cause of the increased amounts of THCA in this condition was found to be due to a metabolic defect in the conversion of this compound into cholic acid. A small amount of (3H)cholic acid was also identified after (3H)THCA administration, confirming that this metabolic defect was incomplete. Varanic acid (3alpha, 7alpha, 12alpha, 24xi-tetrahydorxy-5beta-cholestan-26-oic acid), a metabolite of THCA, could not be identified in either of these patients. By assuming that this compound would be conjugated and excreted if the metabolic block occurred after the formation of varanic acid, the defect in these patients appears to be due to a deficiency of a 24-hydroxylating enzyme system required to convert THCA into varanic acid. This condition appears to be transmitted in an autosomal recessive fashion, because the two affected patients were of opposite sex, and neither a normal sibling nor the two parents have increased amount of THCA in their bile.

Adult↗
PubMedDate not supplied

Evoked potential abnormalities in children with chronic cholestasis.

To assess the effect of chronic cholestasis and vitamin E deficiency on nervous system function, we did multimodality evoked potential testing of 17 children (mean age = 47 months) who had chronic liver disease. Evoked potential testing was repeated periodically in 11 patients 1 to 33 months after the initial study. Eight children had abnormal delays of the P100 peak of the visual evoked potential, and these children each had significantly higher total serum bile acid levels than did children who had normal visual evoked potentials (p = 0.002). Bilateral brainstem auditory evoked potential abnormalities consistent with conductive hearing losses were initially present in six patients. However, persistent conductive losses were found in four patients, all of whom had arteriohepatic dysplasia. Four children had mildly abnormal somatosensory evoked potentials that were due solely to a mild peripheral neuropathy. Biochemical measures of vitamin E status were not consistently associated with either normal or abnormal visual, brainstem auditory or somatosensory evoked potentials or a combination of evoked potential abnormalities, and an abnormality of one evoked potential type was not associated with an abnormality of any other. A similar lack of relationship between evoked potential results and plasma vitamin A measurement was noted. Following marked improvement in or resolution of cholestasis in four patients, the visual evoked potential became normal, but other evoked potentials did not change. Visual evoked potential improvement was greatest in two patients who underwent orthotopic liver transplantation. This is the first report that demonstrates frequent, potentially reversible visual system abnormalities that are associated with cholestasis and cannot be attributed solely to vitamin E and/or A deficiency.(ABSTRACT TRUNCATED AT 250 WORDS)

Abetalipoproteinemia↗
PubMedDate not supplied

Characterization of vitamin E status in cholestatic children by conventional laboratory standards and a new functional assay.

In the present study, the clinical application of a new functional test for vitamin E deficiency was evaluated. Erythrocytes from cholestatic children at risk for vitamin E deficiency and appropriate controls were incubated in vitro with hydrogen peroxide and the malondialdehyde generated and released into the supernatant quantitated. The results of these incubations were compared with fasting plasma vitamin E levels, the ratio of plasma vitamin E to plasma lipid levels, and, in some instances, hydrogen peroxide hemolysis tests. Malondialdehyde formation was less than 6% in controls and vitamin E-sufficient cholestatic children. However, cholestatic vitamin E-deficient children had a mean malondialdehyde formation of 41%. The results also suggest that for children less than 4 months of age, a ratio of plasma vitamin E to total plasma lipids less than 0.6 mg/g may be sufficient to provide protection from in vitro peroxidation. The authors suggest that this functional assay of vitamin E status be included in the evaluation of individuals with the potential for vitamin E deficiency.

Absorption↗