Tyrosinemia type II: Mutation update, 11 novel mutations and description of 5 independent subjects with a novel founder mutation.

BACKGROUND: Tyrosinemia type II, also known as Richner-Hanhart Syndrome, is an extremely rare autosomal recessive disorder, caused by mutations in the gene encoding hepatic cytosolic tyrosine aminotransferase, leading to the accumulation of tyrosine and its metabolites which cause ocular and skin lesions, that may be accompanied by neurological manifestations, mostly intellectual disability. AIMS: To update disease-causing mutations and current clinical knowledge of the disease. MATERIALS AND METHODS: Genetic and clinical information were obtained from a collection of both unreported and previously reported cases. RESULTS: We report 106 families, represented by 143 individuals, carrying a total of 36 genetic variants, 11 of them not previously known to be associated with the disease. Variants include 3 large deletions, 21 non-synonymous and 5 nonsense amino-acid changes, 5 frameshifts and 2 splice variants. We also report 5 patients from Gran Canaria, representing the largest known group of unrelated families sharing the same P406L mutation. CONCLUSIONS: Data analysis did not reveal a genotype-phenotype correlation, but stressed the need of early diagnosis: All patients improved the oculocutaneous lesions after dietary treatment but neurological symptoms prevailed. The discovery of founder mutations in isolated populations, and the benefits of early intervention, should increase diagnostic awareness in newborns.

Resistance or tolerance? Highlighting the need for precise terminology in the field of disinfection.

The terms 'resistance' and 'tolerance' are well defined in the context of antibiotic research. However, in the field of disinfection, these terms are often used synonymously, which creates ambiguity and can lead to misunderstandings and misconceptions. In addition, this inconsistency in terminology makes it difficult to assess the risk of a disinfectant resistance. This general review aims to discuss existing definitions of the terms 'adaptation', 'susceptibility', 'tolerance', 'persistence' and 'resistance' in the light of disinfectants. The most ambiguity is found between tolerance and resistance. Whereas the former describes the not necessarily heritable survival of transient exposure to usually lethal concentrations, resistance is the strictly heritable ability to survive otherwise lethal concentrations of an antimicrobial agent, regardless of exposure time. A simple transfer of experience from antibiotic research is not recommended when assessing the risk of resistance to disinfectants, as there are important differences between antibiotics and disinfectants, although both are antimicrobials: (i) disinfectants are usually applied at concentrations that exceed the minimum inhibitory concentration by orders of magnitude, (ii) the exposure times of disinfectants are in the range of seconds, minutes, or a few hours, (iii) the mode of action of disinfectants is less specific, and (iv) disinfectants often contain more than one active agent with additive or synergistic effects. It is important to recognize that disinfectants, like other antimicrobial agents such as antibiotics, have a dualistic nature and should be used correctly and with caution.

Development of Metabolic Phenotype in Phenylketonuria: Evaluation of the Blaskovics Protein Loading Test at 5 Years of Age.

BACKGROUND: As part of the German Collaborative Study on Phenylketonuria (PKU)/Hyperphenylalaninaemia (HPA) Study Protocol, a Blaskovics protein loading test (180 mg phenylalanine (phe) protein equivalent per kg body weight and day for 72 h) had been applied to 145 children at the age of 6 months. For investigating possible age-related changes of metabolic phenotype, 51 of them received a 2nd loading test at 5 years of age. METHODS: Besides the analysis of blood phe levels, acidic phe transamination metabolites were quantified in urine. RESULTS: Compared to the 6-month data, the mean blood phe level 72 h after start of loading (Phe72) was found to be decreased by 7% (P = 0.06), whereas the mean urinary excretion (per 1.73 m2 body surface and day) of 2-hydroxyphenylacetic acid was increased 1.9-fold (P < 0.01). Corresponding with these analytical data, the kinetic model constant k out of metabolic plus renal phe disposal was found increased 1.3-fold in mean (P < 0.01).In 3 of the 51 patients, Phe72 was very high at 6 months while in the medium range at 5 years, suggesting that catabolic states may mimic a more severe metabolic defect.The blood phe level response of mild PKU (type II) was assigned identically at both ages in 7/9 patients. Diverging results were (i) response type III (mild hyperphenylalaninaemia) at 6 months and type II at 5 years and (ii) type II at 6 months and type III at age 5. CONCLUSION: Renal elimination of OHPAA and phe tolerance increase significantly between the age of 6 months and 5 years, suggesting that, at least in childhood, formation and/or renal disposal of phe transamination metabolites may be major distal determinants of phe tolerance.

Gastroenteropancreatic neuroendocrine tumours contain a common set of synaptic vesicle proteins and amino acid neurotransmitters.

Human neuroendocrine tumours of the gastroenteropancreatic system contain major integral membrane proteins of small synaptic vesicles of neurons, together with characteristic membrane polypeptides of large dense-core vesicles of neurons and neuroendocrine cells. The membrane polypeptides characteristic for small synaptic and large dense-core vesicles are detected in pheochromocytomas (n = 6), functional (n = 6) and non-functional (n = 6) foregut, and midgut carcinoids (n = 17). All gastroenteropancreatic tumours contain large amounts of amino acid neurotransmitters, i.e. glycine and glutamate. gamma-Aminobutyric acid, however, is only found in some foregut carcinoids. Thus, neuroendocrine gastroenteropancreatic tumours possess a vesicle type with a content and membrane composition similar to small synaptic vesicles of neurons.

HFE gene mutation and transferrin saturation in very low birthweight infants.

AIM: To determine if there is an association between high transferrin saturation and the C282Y HFE gene mutation in very low birthweight (VLBW) infants. METHODS: One hundred and forty three VLBW infants receiving recombinant erythropoietin and 3 to 9 mg/kg/day of enteral iron were studied. Genomic DNA was extracted from filter paper cards. The C282Y mutation was determined by restriction fragment length polymorphism analysis. RESULTS: Six infants were heterozygous for the mutation; none was homozygous. Ten infants had a transferrin saturation above 80% at least once. No infant was positive for both transferrin saturation above 80% and the mutation. CONCLUSIONS: The data strongly suggest that there is no association between high transferrin saturation and the HFE gene mutation in VLBW infants during the first weeks of life.

Experimental evaluation of a cell module for hybrid liver support.

Aim of the study was to evaluate a hybrid liver support system in a porcine model of acute liver failure, after hepatectomy. Pigs with a body weight of 70+/-18 kg underwent total hepatectomy and porto-cavo-caval shunting as well as ligation of the bile duct and the hepatic artery. Control animals were connected to the system (including capillary membrane plasma separation) containing a four compartment bioreactor with integral oxygenation and decentralized mass exchange but without liver cells. The treatment group received hybrid liver support with the same system including 370+/-42 g primary isolated porcine parenchymal liver cells in co-culture with hepatocyte nursing cells, tissue engineered to liver- like structures at high density. Treatment started after complete recovery from anesthesia and was performed continuously. A positive influence on peripheral vascular resistance and a reduced need of catecholamine dosage was observed in the treatment group. Hybrid liver support with a cell module upscaled for clinical application significantly prolonged survival time in animals after hepatectomy with the longest survival being 26 hours in the control group an 57 hours in the treatment group.

[Increased epidemic incidence of hepatitis B in a district hospital]. / Uber gehäuftes epidemisches Auftreten der Hepatitis B in einem Kreiskrankenhaus.

It is reported on an epidemic of hepatitis B of 29 patients in a district hospital. Due to diagnostic errors in importation and a more frequent appearance of diseases of hepatitis B in the surgical department and the 2nd medical department, in which above all diabetics are treated, took place. The average age of the patients was 55 years. In all patients the clinical course was to be regarded as severe. 4 of 29 patients died. In all patients the hepatitis B disease showed a pronounced jaundice with high transaminases, particularly the SGOT and LAP were clearly increased. Also the duration of the presence was longer than in hepatitis A as well as the transition into chronic hepatitis was more frequent. By diagnostic information of the physicians and the other medical staff as well as improved measures of desinfection the epidemic could be restricted.

[Creatinine concentration, osmolar concentration and blank color as basis for concentration dependent values in urine (author's transl)]. / Kreatininkonzentration, Osmolalität und Eigenfarbe als Bezugsgrössen für Konzentrationsangaben im Urin

The correlation between Creatinine concentration, osmolality and blank color of urines was investigated. Only values of creatinine concentration and osmolality allow an approximative inter-conversion. For urine analysis, especially in cases of a very high creatinine concentration, we recommend to measure osmolality as a control.

Haplotype analysis of the phenylalanine hydroxylase gene in Turkish phenylketonuria families.

We have estimated the haplotype distribution of mutant and normal phenylalanine hydroxylase (PAH) alleles for 17 Turkish phenylketonuria (PKU) families: 20 normal and 27 mutated PAH alleles could be identified. Of the latter, the most prevalent were associated with haplotype 6 (29.6%), 1 (18.5%) and 36 (11.1%), while the normal alleles were preferentially associated with haplotype 1 (20%). Of the 19 different haplotypes observed, 5 have not been described previously. The haplotype distribution differed significantly from that of the Northern European population. Two of the eight polymorphic sites were in association with PKU. No deletions of exon sequences were found in the families analysed.

[Thin layer chromatographic test for the indirect and direct detection of the enzyme defect in histidinemia]. / Indirekter und direkter dünnschichtchromatographischer Nachweis des Enzymdefektes bei der Histidinämie.

A thin layer chromatographic method for the direct and indirect detection of the enzyme defect in histidineemia is described. Histidin and urocanic acid are analyzed in 0,2-1 mg stratum corneum for specific screening. 5-10 mg skin biopsy material is needed for the direct measurement of the enzyme activity. This simple metabolic test is convenient even in normal hospital laboratories.

Hypotonic unmasking of erythrocyte receptor sites.

The study reports on plasmalemmal perturbation of erythrocytes under osmotic stress. In comparison with isotonic human erythrocytes a 10 minutes incubation in 150 mosm sodium cacodylate pH 7.4 at 20 degrees C results in an increase of the anti AH P binding rate by a factor of two. 0.1 M N-acetyl galactosamine inhibits the binding of anti-AH P of both isotonic and hypotonic red cells. Contrary to isotonic mouse erythrocytes the agglutination with peritoneal murine leukocytes of hypotonic red cells is greatly enhanced provided the erythrocytes have been incubated in autologous serum. The findings are considered evidence of the unmasking of binding sites due to nonspecific rearrangement of membrane constituents.

[Medium-chain acyl-CoA dehydrogenase defect. Acute cerebral episodes and nonketotic hypoglycemia in children]. / Medium-Chain-Acyl-CoA-Dehydrogenase(MCAD)-Defekt. Akute zerebrale Episoden und nicht-ketotische Hypoglykämien bei Kindern.

A four-year-old and a three-year-old boy with somnolence, coma and hypoglycaemia were found to have a defect in the beta-oxidation of medium-chain fatty acids (medium-chain acyl CoA dehydrogenase [MCAD] defect). The brother of one of them had died aged 16 months of an acute disease resembling Reye's syndrome (coma, fatty liver, cerebral oedema). The other two boys have no symptoms now under daily treatment with 100 mg/kg carnitine and frequent carbohydrate-high, fat-poor meals. The MCAD defect is inherited as an autosomal recessive trait and should be considered in the differential diagnosis of unexplained loss of consciousness in children with non-ketotic hypoglycaemia or with Reye's syndrome, as well as in families with sudden infant death.

[Phenylalanine-free amino acid mixture: metabolic effects in relation to a single dose]. / Phenylalaninfreie Aminosäurenmischung: Stoffwechselwirkung in Abhängigkeit von der Einzeldosis.

In the dietetic treatment of phenylketonuric patients phenylalanine free amino acid mixtures are given to meet the protein requirement of the patient. In four healthy probands we tested the metabolic effects of four different PKU-preparations given in variable amounts ingested with carbohydrate and fat containing meals. We determined glucose, insulin, amino acids, and urea in blood. Following the amino acid load we saw an increased insulin output with a hypoglycemic reaction or, with smaller amounts a lack of the normal postprandial blood glucose increase. Hyperaminoacidemias depended on the amount of amino acids ingested. The increase of blood urea found suggests that part of the amino acids were degraded. To compare the results we studied a PKU-patient. He showed corresponding but milder effects.

Clinical features and diagnostic approach in type I tyrosinaemia in an infant with cytomegaly virus infection and bacterial sepsis.

A severely ill 2-month-old female infant was admitted with meningitis and septicaemia caused by Streptococcus pneumoniae. The patient, who also had an acute cytomegalovirus (CMV) infection, revealed the typical clinical and biochemical characteristics of type I tyrosinaemia (TIT). Clinical evidence of severe hepatocellular damage was shown, but urinary succinylacetone was not detected. The diagnosis of TIT was finally confirmed by decreased activity of fumarylacetoacetase (FAA) in skin fibroblasts from the patient and both parents. Following dietary treatment and after overcoming the bacterial and viral infection, the patient's liver function improved.

Utilisation of amino acid mixtures in adolescents with phenylketonuria.

The nutritional regimen of patients with phenylketonuria (PKU) comprises a diet of natural proteins and phenylalanine (Phe)-free amino acid (AA) mixture. The main daily protein requirement is covered by a Phe-free AA mixture. In an adult with PKU, the consumption of the daily AA requirement in one single dose at breakfast caused nausea and vomiting. Therefore, four studies were designed to investigate the adverse and metabolic effects resulting from large intakes of AA mixtures used in the treatment of PKU patients with respect to the following: (1) biochemical effects following consumption of one single dose of Phe-free AA mixture in healthy persons; (2) transient metabolic changes caused by different individual regimens of AA intake in healthy persons and in one PKU patient; (3) nitrogen excretion in PKU patients taking the AA mixture in two or three portions; and (4) catabolic metabolism of AA in a PKU patient. In healthy subjects following the ingestion of the AA mixture in one bolus there was an increase in the blood levels of the given AA and also an increase in blood insulin concentration and a decrease in blood glucose concentration. These changes were less marked when the AA mixture was divided into three portions per day. In contrast, in a PKU patient following the ingestion of AA there was an increase in blood glucose. The urinary nitrogen excretion was greater in PKU patients when one compared to three portions of AA mixture was taken. The consumption of the daily requirement of AA mixture in one single does produced increased catabolism in a PKU patient. In conclusion it is recommended that the total daily amount of AA mixture should be divided into a minimum of three portions.

Liver pathology in transient neonatal hyperammonemia.

Ultrastructural investigations have been performed on two cases of transient neonatal hyperammonaemia (TNH). This newly recognized metabolic disorder is chiefly characterized by severe hyperammonaemia in the postnatal period, a comatous state, absence of abnormal organic aciduria, normal activity of urea cycle enzymes and, usually, complete recovery. The aetiology is presently unknown. Electron microscopy uncovered rather congruent alterations of hepatocyte structure, with a wide spectrum of mitochondrial lesions, an increase of autophagous bodies with organelle remnants, and changes in the excretory apparatus. Thus, in contrast to some of the hereditary disorders of the urea cycle, no specific structural changes could be found in TNH. This finding is in line with the observation of normal activities of main urea enzymes in these cases, and indicates that a different biochemical system may be pathogenetically involved in TNH.

Dependence of the utilization of a phenylalanine-free amino acid mixture on different amounts of single dose ingested. A case report.

For patients with phenylketonuria the daily ingested phenylalanine-free amino acid mixture is the most important source of nitrogen. It is recommended to ingest one third of the total amount combined with main meals. Some patients, especially the older ones, do not follow this recommendation; they ingest the entire daily amount of amino acid mixture in one portion. This intake mode leads to an increased oxidative utilization of the amino acids. To set up an example for this metabolic phenomenon, a 13C-leucine breath test was performed in one female phenylketonuric patient. She ingested a third of her daily amount of the amino acid mixture combined with an oral tracer of 3 mg 13C-leucine/kg body weight at breakfast. The breath test was carried out by a standardized time schedule over 5 h. Three days later the breath test was repeated when she ingested the total amount of amino acid mixture in only one portion at breakfast. Total daily caloric intake and food composition were not changed. On both days a 24 h urine was collected to determine total nitrogen loss. The 13C-content of expired air was analysed by gas isotope ratio mass spectrometry, the total nitrogen content was determined using a combustion unit. The 13C-elimination rate as a percentage of the applied 13C-tracer was 9.5% on the first test day as compared to 19.6% on the 2nd day. The corresponding total nitrogen excretion was increased (4.3-6.9 g/24 h).(ABSTRACT TRUNCATED AT 250 WORDS)