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Biomedical subjects

H K Berry

Publications and source records attributed to H K Berry.

At least 37 records · Page 2Linked to original sources
PubMed1982

Diagnosis of phenylalanine hydroxylase deficiency (phenylketonuria).

Needle liver biopsies were carried out on patients with phenylketonuria (PKU) to establish a diagnosis either of partial or complete phenylalanine hydroxylase (PH) deficiency. Ten phenylketonuric patients and two parents were studied. Nine of the ten patients had completed a three-day oral phenylalanine challenge. Each met the accepted criteria as having classic PKU, based on a sustained rise in the serum phenylalanine level greater than 20 mg/dL. A diagnosis of classic PKU was confirmed in six patients by the absence of hepatic PH activity. Four of the PKU patients had PH activity ranging from 9% to 24% of that found in liver from non-PKU control subjects. The two parents had 27% and 42% of the PH activity found in the control subjects; their child had no activity. Current methods for distinguishing partial from complete PH deficiency are not always reliable, and the degree of the deficiency can best be established by direct measurement of the enzyme in liver.

Biopsy, Needle↗
PubMed1982

Reduction of cerebrospinal fluid phenylalanine after oral administration of valine, isoleucine, and leucine.

A supplement of the branched chain amino acids, valine, isoleucine, and leucine (VIL) was administered orally to patients with phenylketonuria, either together with unrestricted diet of natural protein or with a low phenylalanine diet. The VIL supplement brought about a significant reduction of the cerebrospinal fluid-serum ratio of phenylalanine from a mean value of 0.254 without VIL to 0.204 with VIL. The reduction varied from 15-40% (mean 21%). Concentrations of glycine, lysine, methionine, threonine, tryptophan, and tyrosine were within normal limits in serum and cerebrospinal fluid of infants with phenylketonuria. No amino acid imbalance was created by the supplement and no adverse effects from VIL were observed.

Administration, Oral↗
PubMed1982

Gas-chromatographic/mass spectrometric detection of 3-hydroxy-3-methylglutaryl-CoA lyase deficiency in double first cousins.

Gas chromatography/mass spectrometry was used for the detection of 3-hydroxy-3-methylglutaryl-CoA lyase (EC 4.1.3.4) deficiency in double first cousins. This enzyme is in the last step of leucine catabolism and is also involved in ketogenesis. Quantitation of urinary organic acids as their cyclohexyl esters demonstrated increased concentrations of 3-hydroxy-3-methylglutaric acid, 3-methylglutaconic acid, 3-methylglutaric acid, and 3-hydroxyisovaleric acid. The procedure is more rapid, sensitive, and specific than previously reported gas-chromatographic methods for acid quantitation. The affected children initially presented with symptoms similar to Reye's syndrome; the acids were quantitated during periods of altered intake of protein and fat. Both leucine and fat intake contributed to increased acid excretion. These studies suggest that life-threatening episodes of hypoglycemia are best prevented with a low-protein, low-fat diet.

Amino Acid Metabolism, Inborn Errors↗
PubMed1981

Progress in experimental phenylketonuria: a critical review.

Experimental progress in the development of an accurate and useful model of phenylketonuria (PKU) during the last 15 years is reviewed in detail. From this review it is clear that the recent emergence of models using the combined administration of phenylalanine (phe) and p-chlorophenylalanine (PCPA) constitutes a major success that lays the groundwork for future research into the pathogenesis and treatment of PKU. Biochemical evidence on the pathophysiology of PKU is also briefly reviewed in the context of the behavioral and biochemical adequacy of the models used. It appears that in the past biochemical investigations into PKU have been impaired by use of inadequate models, a situation that should now change if the best of the phe-PCPA models are more widely adopted. New trends in PKU research involve the role of large neutral amino acids other than phe as potential aids in the treatment of PKU and the appearance of a new model based on the use of alpha-methylphenylalanine (AMPhe) combined with phe. It appears that PKU research may be on the brink of a new and productive era as investigations into these promising areas unfold and as new emerge through the full utilization of existing models.

Abnormalities, Multiple↗
PubMed1980

Elevated meconium lactase activity. Its use as a screening test for cystic fibrosis.

Screening of newborn infants could provide information needed to evaluate the effects of early treatment on the course and prognosis of cystic fibrosis (CF). Two procedures of screening meconium for CF were compared: increased albumin levels, detected by a commercial test strip; and increased lactase activity, detected by glucose production after incubation of meconium with lactose. Specimens positive by the lactase test were retested for albumin. Low-birth-weight infants accounted for more than half the positive test results with both procedures. Sweat chloride measurements were carried out only on infants whose meconium specimens had albumin concentration greater than 12 mg/g (wet weight), measured by radial immunodiffusion. Twelve infants with CF were identified through screening, six while testing 44,816 specimens by lactase activity test. Three additional infants with CF were missed because meconium specimens were negative to both tests.

Albumins↗
PubMed1979

Identification and quantitation of urinary dicarboxylic acids as their dicyclohexyl esters in disease states by gas chromatography mass spectrometry.

Clinical studies were conducted by gas chromatography mass spectrometry selected ion monitoring of urinary dicarboxylic acids as dicyclohexyl esters. The dicyclohexyl esters of the dicarboxylic acids give characteristic electron impact mass spectra suitable for selected ion monitoring. The mass spectra exhibit a prominent acid + 1H ion and an (acid + 1H)-H2O ion for use as quantitating and confirming ions. The cyclohexyl esters are stable for days at room temperature and have excellent chromatographic properties. Dicarboxylic acid quantitation is performed within one hour using only 50 microliter of unpurified urine. A rapid method specifically for methylmalonic acid quantitation is described which has assisted physicians in the diagnosis of pernicious anemia and methylmalonic aciduria. This procedure is applicable for screening urinary organic acids for detection of inborn errors of metabolism. The detection of a child with elevated medium length dicarboxylic acids in the terminal urine specimen is reported. This condition, previously described as an inborn error, is attributed to a terminal event. Finally, an increase in urinary succinic acid paralleling putrescine levels is described during a response to cancer chemotherapy.

Dicarboxylic Acids↗
PubMed1979

Distribution of phenylalanine hydroxylase (EC 1.14.3.1) in liver and kidney of vertebrates.

The range of phenylalanine hydroxylase activity was determined by measuring the conversion of radioactive phenylalanine to tyrosine in liver and kidney of various vertebrates. Rodents (rats, mouse, gerbil, hamster and guinea pig) were found to have the highest liver phenylalanine hydroxylase activity among all animals studied. They are also the only species that possessed a significant kidney phenylalanine hydroxylase activity which was about 25% of that found in the liver of the same animal. The synthetic dimethyl-tetrahydro-pteridine, used as a cofactor for the enzyme assay in most studies, catalyzed non-enzymatic hydroxylation of phenylalanine to tyrosine. Inclusion of boiled-blank and strict control of timing between incubation and product measurement were essential precautions to minimize erroneous results from substrate contamination and non-enzymatic hydroxylation.

Animals↗
PubMed1979

Intellectual development and academic achievement of children treated early for phenylketonuria.

Twenty early-treated children with classical phenylketonuria (PKU), five early-treated children with variant PKU and seven untreated children with hyperphenylalinemia were compared with non-PKU family members in terms of intellectual development, and 14 school-age PKU children were also compared for academic achievement. For the early-treated children with classical PKU, mean IQ (98) was within the normal range, but nine of these 20 children had IQ scores more than 1SD below those of family members. There was a significant negative correlation between phenylalanine concentrations at one to four years of age and later measured intelligence in these early-treated children, but this was probably a consequence of poor dietary control in the early years. The early-treated children with variant PKU and those with hyperphenylalaninemia had IQ scores consistent with those of unaffected family members, but untreated children with variant PKU had scores significantly lower than their own early-treated siblings. Achievement scores of the early-treated PKU children were consistent with their intellectual ability: they and their non-PKU siblings had similar standard scores for reading and spelling, but arithmetic scores were significantly lower for the PKU children. Early-treated children whose diet had been discontinued had achievement scores in all subjects below those predicted from their IQS.

Achievement↗
PubMed1978

Galactose-1-phosphate accumulation by a Duarte-transferase deficiency double heterozygote.

An infant, suspected of having galactosemia following a positive screening test on dried blood spots, was shown to be a Duarte-transferase deficiency compound heterozygote through studies of electrophoretic mobility of the transferase enzyme in blood from the patient and family members. No rise in blood glucose was seen following oral ingestion of galactose. At the same time, galactose rose in plasma and was excreted in the urine; galactose-1-phosphate accumulated in erythrocytes. A galactose-free diet was considered the prudent course in the presence of the patient's inability to metabolize galactose completely.

Blood Glucose↗
PubMed1977

Induced PKU in rats: effects of age and melatonin treatment.

Newborn rats injected on Days 1-8 of life with L-phenylalanine (2 g/kg) and p-chlorophenylalanine (80 mg/kg) displayed biochemical symptoms analogous to human phenylketonuria (PKU) and maze learning impairments. The behavioral effects were less evident in rats treated on Days 9-16 or 7-24. None of the symptoms observed were alleviated by simultaneous administration of melatonin (10 mg/kg/day).

Aging↗
PubMed1977

Tyrosinemia with acute intermittent porphyria: aminolevulinic acid dehydratase deficiency related to elevated urinary aminolevulinic acid levels.

A patient who had hereditary tyrosinemia was observed during two illnesses to have characteristics of acute intermittent porphyria with associated hypertension. Metabolic studies revealed elevated levels of urinary aminolevulinic acid but normal levels of porphyrin metabolites associated with, and possibly explained by, decreased red blood cell activity of the zinc-dependent enzyme, aminolevulinic acid dehydratase. Zinc deficiency could not be directly associated with the diminished enzyme activity. The patient's hypertension appeared to be related to increased urinary excretion of catecholamines and to elevated renin activity in peripheral venous blood.

Adolescent↗