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Biomedical subjects

O M Rennert

Publications and source records attributed to O M Rennert.

At least 91 records · Page 5Linked to original sources
PubMed1981

Urinary polyamines in preterm infants.

Polyamines were determined in urine of 22 preterm infants (mean 30.0 weeks gestation) from birth to 22 weeks of age, and in full-term infants in the first week of life. A significant decline in urine putrescine and spermidine levels occurred with increased postnatal age in preterm infants. At expected term preterm infants had significantly higher levels of polyamines in urine than full-term infants at the same postconceptional age. No constant correlations between weight or linear growth velocity and urinary polyamine excretion could be established in this group of infants. Altered urine polyamine values were detected in two clinical situations: hyperbilirubinemia was associated with increased urine spermidine (and with increased spermidine/putrescine ratio), and liver disease was associated with increased levels of both putrescine and spermidine in urine.

Female↗
PubMed1981

Interconversion, catabolism and elimination of the polyamines.

Two catabolic pathways exist for spermidine and spermine. One is responsible for the interconversion of the polyamines, a physiological intracellular event. The first and probably rate limiting step of the polyamine interconversion pathway is acetylation in the N1-position by a cytosolic enzyme. The reaction products N1-acetylspermine and N1-acetylspermidine are substrates of the cytoplasmic polyamine oxidase. This enzyme transforms the N1-acetylpolyamines into spermidine and putrescine respectively. N1-Acetylspermidine is at the same time a major urinary excretion product. The factors which control the rates of N1-acetylspermidine degradation by polyamine oxidase versus its elimination via transport are not known. The second catabolic pathway forms putreanine from spermidine and N8-(2-carboxyethyl)-spermidine and spermic acid from spermine. It is catalyzed by the well known serum spermine oxidase. The second step in this reaction sequence, the dehydrogenation of the aldehydes formed by the serum spermine oxidase occurs intracellularly and is catalyzed either by specific or non-specific aldehyde dehydrogenases. The function of this "two compartment reaction sequence" is most probably to protect tissues from extracellular or exogenous (alimentary) polyamines. Its end-products appear to be physiologically indifferent urinary excretion products. Both catabolic pathways may have marked effects on the urinary polyamine pattern. Drugs as well as a variety of physiological and pathological states may influence polyamine catabolism and elimination at various levels, and may cause characteristic alterations in the urinary excretion of free and conjugated polyamines and of the amino acids deriving from the polyamines.

Acetylation↗
PubMed1980

Copper and ceruloplasmin activity in human amniotic fluid.

The variation in the level of copper and ceruloplasmin oxidase activity in human amniotic fluid from 20 weeks' gestation to term was reported. The protein content of amniotic fluid decreased toward term. A definite decreasing trend of concentration of copper, expressed both as nanograms of copper per milliliter of amniotic fluid and nanograms of copper per milligram of protein, was also observed from midgestation toward term. Ceruloplasmin, on the other hand, demonstrated a significant increase from the period 20 38 weeks' gestation, with a subsequent decline after 38 weeks.

Amniotic Fluid↗
PubMed1980

Polyamine metabolism in Menkes kinky hair disease.

Clinical investigations of the urinary excretion of putrescine and the polyamines spermidine and spermine in a patient with Menkes kinky hair disease are reported. This disorder, characterized by intra- and extracellular copper deficiency, is associated with significant depression of diamine oxidase and monoamine oxidase activity. Urinary excretion of diamine and polyamines, monitored over a 2-month interval in a 4-month old patient with Menkes kinky hair disease, documented a 3- to 10-fold increase in the excretion of free putrescine, spermidine and spermine as well as the conjugated derivatives of putrescine and spermidine. These observations suggest that abnormalities in diamine and polyamine concentration occur in disease states in which the metabolic transformation of these compounds is impaired.

Amine Oxidase (Copper-Containing)↗
PubMed1980

Genetic expression of Wilson's disease in cell culture: a diagnostic marker.

Wilson's disease fibroblasts have an elevated intracellular copper concentration as compared to cultured control cells. A decreased ratio of copper to protein was observed in cytoplasmic protein (or proteins) having a molecular weight greater than or equal to 30,000 in Wilson's disease cells. The results of this culture study indicate its potential importance in the early unequivocal diagnosis of this disorder.

Adolescent↗
PubMed1980

Multiple sulfatase deficiency (mucosulfatidosis): impaired degradation of labeled sulfated compounds in cultured skin fibroblasts in vivo.

Skin fibroblasts from a Japanese patient with multiple sulfatase deficiency (MSD) (Mucosulfatidosis) were studied with regard to metabolism of various sulfated compounds in vivo. Several sulfatase activities (arylsulfatases A, B and C, cholesterol sulfatase, heparin N-sulfatase) were deficient in skin fibroblasts grown in F-10 CO2 medium. The accumulation and degradation of 35S-sulfatide, 35S-mucopolysaccharides, 14C-cholesterol sulfate by MSD cells were also studied, comparing them to control, Hunter and metachromatic leukodystrophy cells. MSD fibroblasts accumulated and failed to degrade these compounds in vivo. Cholesterol sulfate was also incorporated into the control and pathological cells, and MSD cells were unable to hydrolyze cholesterol sulfate, though cholesterol sulfate is known to be hydrolyzed in the non-lysosomal subfraction. From these data it is clear that multiple enzyme deficiencies in MSD fibroblasts can be demonstrated in vivo.

Cells, Cultured↗
PubMed1980

Correlation of plasma propylthiouracil levels with inhibition of thyroid hormone synthesis in the rat.

The inhibition of thyroid hormone synthesis was studied in relation to plasma levels of 6-n-propyl-2-thiouracil (PTU). Na 125I (5 muCi) was injected i.p. into adult male Sprague-Dawley rats. After 30 min, graded doses of PTU (0.2 mg/kg. 0.1 mg/kg, and 0.05 mg/kg) were similarly injected. Thyroid hormone synthesis was followed by the accumulation of radioactivity into thyroid glands, which were removed at specified time intervals. PTU levels were measured spectrophotometrically at the time of sacrifice. A-ditionally, PTU (35S) was used to confirm blood levels of PTU and also to follow intrathyroidal PTU levels. Plasma PTU levels in excess of 0.18 microgram/ml completely inhibited thyroid hormone synthesis. Levels between 0.14 and 0.09 microgram/ml had a partial effect, and PTU levels less than 0.09 microgram/ml had no effect on thyroid hormone synthesis.

Animals↗
PubMed1980

Cystic fibrosis factors: effect of serum on the secretory response of dispersed rat submandibular cells.

The action of serum from cystic fibrosis patients on the intracellular maintenance, efflux, and uptake of potassium ions in dispersed acinar cells from the rat submandibular gland, a seromucous salivary gland, was investigated in an attempt to demonstrate the presence of factors affecting ion-coupled secretion. No effects specific to cystic fibrosis serum were demonstrated upon the following parameters of potassium transport: (1) maximal stimulation of K+ efflux by the cholinergic agonists carbamylcholine; (2) the dose-response curve of K+ efflux in response to carbamylcholine; (3) re-entry of K+ into cells after carbamylcholine stimulation; (4) the maintenance of K+ in the absence of added effectors. No differences were observed between cells pretreated with serum and cells to which serum was added at the time of cholinergic stimulation of secretion. At high concentrations, serum from both normal individuals and those with cystic fibrosis severely damaged the cells in a rapid and irreversible fashion. K+ transport has a direct, closely coupled, specific relationship to secretory activity and is Ca++ dependent in this system. From these observations, we conclude that serum from individuals with cystic fibrosis does not contain chemical compounds which specifically alter the major components of ion-coupling to secretion or the secretory process itself in salivary gland acinar cells.

Adolescent↗
PubMed1980

Polyamine-peptide conjugates: proposed functions.

Six polyamine-conjugated proteins were identified in human amniotic fluid. Three contained covalently bound spermine, one contained covalently bound spermidine, and two contained covalently bound putrescine. All were characterized by high content of serine, glycine, glutamate, and aspartate. Polyamination of proteins may participate in mechanisms for (1) polyamine specificity in cell growth; (2) cell surface attachment of polyamines; (3) transport of polyamines; (4) endocytosis and other cellular uptake processes; and (5) signaling protein degradation.

Amino Acids↗
PubMed1979

Isolation and characterization of a polyamine-peptide conjugate from human amniotic fluid.

Significant amounts of the diamine putrescine and the polyamines spermidine and spermine could be detected in human third-trimester amniotic fluid only after acid hydrolysis. This observation was interpreted to mean that these amines existed only in conjugated form in this biological fluid. Upon fractionation by ultrafiltration 90--10% of the putrescine was associated with the 1000--10 000 dalton fraction. Spermine was identified in this fraction and in a low-molecular weight fraction presumably representing acetylated derivatives. Spermidine was entirely associated with the 10 000--30 000 dalton fraction. The putrescine conjugate was purified to homogeneity by column chromatography on Biogels P10 and P6 followed by ion-exchange chromatography on DEAE-Sephadex A-25. Molecular weight by gel exclusion using peptide standards was estimated to be approx. 4600. The UV absorption spectrum of the putrescine conjugate conformed to that expected for a polypeptide. This putrescine conjugate contained 39 identified amino acids with a combined molecular weight of 4713. Putrescine was detectable by high pressure liquid chromatography only after acid hydrolysis of the conjugate. No other polyamines were detected in these hydrolyzates, nor were any polyamines demonstable in hydrolyzates of control peptides nor in pooled column washes. The identity of the putrescine determined by high pressure liquid chromatography was confirmed by a two-dimensional thin-layer chromatography method. These results establish the in vivo production of a putrescine--polypeptide conjugate in man. Such molecular species may constitute yet another metabolic pathway for polyamines or may reflect another mode of post-translational modification of polypeptide structure and function. The qualitative and quantitative analysis of polyamine conjugate in human aminotic fluid may prove to be useful in the detection of abnormalities in fetal development.

Amino Acids↗
PubMed1979

Polyamine conjugates and total polyamine concentrations in human amniotic fluid.

A study of the quantitative profile of polyamines in amniotic fluid from the 13th through the 40th week of gestation was undertaken. These experimental observations indicate the absence of free putrescine, spermidine and spermine throughout gestation. Quantities of acid-liberated putrescine, spermidine and spermine are highest in late first and late third trimester. Putrescine is associated with peptide or peptides of molecular weight 1000 to 10 000 throughout gestation. Spermidine is found in amniotic fluid covalently conjugated to peptide or peptides with molecular weight 10 000 to 30 000. Spermine appears to exist in amniotic fluid, both in the higher molecular weight fraction (1000 to 10 000) and as acetylated derivatives. The existance of polyamine conjugates is compatible with an in vivo function in the regulation of embryonic growth and development. Abnormalities in polymines conjugated to peptides or their concentration may be useful in the diagnosis of fetal maldevelopment.

Amniotic Fluid↗
PubMed1979

Folate antagonism following teratogenic exposure to diphenylhydantoin.

Previous studies have reported indirect evidence for the mediation of folate antagonism in the induction of malformations by diphenylhydantion. We have demonstrated that a teratogenic regimen of folate-deficiency and antagonism using 9-methyl PGA in the rat produces significantly decreased rates of oxygen consumption in the maldeveloping embryos. The present study reports similar reductions in oxygen uptake by mouse embryos from mothers treated with teratogenic doses of diphenylhydantoin, and documents a significant depression of the actual folate levels in such embryos. The differences are less significant with lower doses of diphenylhydantoin, and do not occur with a nonteratogenic dose.

Abnormalities, Drug-Induced↗
PubMed1979

Mucopolysaccharides in osteochondrodysplasias.

Mucopolysaccharide (MPS) metabolism in cultured skin fibroblasts was studied in one case of each of the following osteochondrodysplasias: chondrodysplasia punctata of the rhizomelic type, thanatophoric dysplasia, campomelic dysplasia, and osteogenesis imperfecta congenita. Accumulation of both sulfated and non-sulfated MPS, as well as secretion of total MPS, was normal in chondrodysplasia punctata of the rhizomelic type and in thanatophoric dysplasia. Accumulation of both sulfated and non-sulfated MPS was normal in campomelic dysplasia. Lastly, accumulation of sulfated MPS was normal in osteogenesis imperfecta congenita.

Cells, Cultured↗