Fructose breath hydrogen test--is it really a harmless diagnostic procedure?

Usage of hydrogen breath tests has become one of the standard procedures in diagnosing chronic unspecific abdominal pain. These tests are said to be of sufficient specificity and sensitivity, are easily done, non-invasive and are more often practiced in outpatients. A 13-year-old boy is reported with chronic unspecific abdominal pain and growth retardation and so far misdiagnosed hereditary fructose intolerance (HFI), who developed life-threatening adverse effects during the fructose breath hydrogen test. It is concluded that the possibility of HFI should be excluded first by a carefully explored dietary history before the fructose breath test is performed under medical supervision. If there is any suspicion of HFI, a molecular genetic analysis should be preferred.

[Diagnosis of Hermansky-Pudlak syndrome]. / Diagnostik des Hermansky-Pudlak-Syndroms.

HISTORY AND ADMISSION FINDINGS: A 27-year-old woman presented with increased bleeding tendency and known oculocutaneous albinism. In addition to frequent nasal and gingival bleedings she had since childhood spontaneous extensive cutaneous bleedings. In addition she was extreme sensitive to UV light with visual disturbances. Bone-marrow biopsy when aged 9 years had revealed abnormal pigment-storing cells. Physical examination showed a very fair skin and hair, spontaneous nystagmus and extensive rash in the face. INVESTIGATIONS: Prothrombin, partial thromboplastin and thrombin times as well as fibrinogen level were normal. On re- admission bleeding time varied greatly, while platelet count was normal. Mean platelet volume was slightly reduced. Von Willebrand antigen, factor VIII:C, factor IX:C, factor XIII and alpha (2)-antiplasmin were all normal. Aggregometry indicated abnormal platelet function; there was reduced platelet aggregation after stimulation with adenosine diphosphate. Flow cytometry of whole blood demonstrated abnormal storage function of thrombocytic delta-granules. The underlying cause of the described symptoms was shown to be a gene defect in typical location on the long arm of chromosome 10. DIAGNOSIS AND TREATMENT: The triad of tyrosinase-positive oculocutaneous albinism, abnormal thrombocytic delta-granules and ceroid deposition in the cells of the reticuloendothelial system or the bone-marrow is called Hermansky-Pudlak syndrome (after those who first reported it). There is as yet no causal treatment. But the patient was advised to use a nasal spray of desmopressin for spontaneous or difficult to stop bleedings after minor injuries. Desmopressin i. v. should be given prophylactically before any operation.

Stability of ketone bodies in serum in dependence on storage time and storage temperature.

The serum concentrations of beta-hydroxybutyrate and acetoacetate as well as the beta-hydroxybutyrate/acetoacetate ratio are important parameters for the differential diagnosis of certain inborn errors of metabolism. Acetoacetate, however, is an unstable compound which becomes rapidly decarboxylated. At a storage temperature of -20 degrees C about 40% of the acetoacetate is lost within 7 days and after 40 days storage at this temperature virtually all of the acetoacetate has become degraded. At -80 degrees C the decomposition of acetoacetate occurs with a much slower rate and only 15% of the initial acetoacetate is lost after 40 days storage. The rate constants for the decarboxylation reaction were found to be (6.4 +/- 2.9) * 10(-5) [min(-1)] at -20 degrees C and (0.4 +/- 0.3) * 10(-5) [min(-1)] at -80 degrees C. In contrast, beta-hydroxybutyrate is very stable during storage and hence should be used as main parameter for the evaluation of ketonemia. If determination of acetoacetate and/or of the beta-hydroxybutyrate/acetoacetate ratio is necessary, an assay immediately after collecting the serum samples is recommended. Otherwise, the serum samples should be frozen as soon as possible and stored at -80 degrees C during transport and storage.

Cloning and characterization of another lignin peroxidase gene from the white-rot fungus Phanerochaete chrysosporium.

Lignin peroxidase (LiP) isozymes of Phanerochaete chrysosporium are encoded by a large family of closely related genes, whose total number is still unknown. Among genomic clones, obtained using the polymerase chain reaction to clone the LiP gene LPOA from Phanerochaete chrysosporium strain BKM-F 1767, another LiP gene was found. This gene, HG3, showed more than 95% nucleotide homology to those LiP gene variants which encode LiP isozyme H8. The gene encodes a protein of 372 amino acids, including the typical leader sequence for secretion, that is identical to the LiP isozyme H8 except for 6 amino acid substitutions.

Results of selective screening for inborn errors of metabolism in the former East Germany.

Since the early 1970s selective screening for inherited metabolic disorders has been performed in larger children's hospitals or metabolic centres of the former East-Germany. As a rule the following methods were employed: initially paper chromatography, drop, dip and spot tests, later on thin-layer chromatography and more recently enzyme analysis, gas chromatography, mass spectrometry and HPLC. Normally urine, blood or leucocytes were investigated. The diagnoses were confirmed in metabolic centres in Greifswald, Berlin or Leipzig or in collaboration with specialized laboratories abroad. About 130,000 subjects from former East Germany as well as from different East European countries were investigated, of which 365 patients were diagnosed and classified into roughly 40 various metabolic diseases. The proportion of positive diagnoses was 1 in 400.

Interaction of 5-azacytidine and dexamethasone in the control of hepatic tyrosine aminotransferase.

The nucleoside analog 5-azacytidine is able to induce tyrosine aminotransferase several-fold in the liver of suckling rats. Bilateral adrenalectomy abolishes this inducing effect. The drug also decreases significantly the concentration of cytosolic glucocorticoid receptor accompanied by an increase of the glucocorticoid receptor concentration in the nuclei. The antiglucocorticoid RU 486 which abolishes the induction of tyrosine aminotransferase and serine dehydratase by dexamethasone very effectively is not able to inhibit either the induction of tyrosine aminotransferase or the translocation of the glucocorticoid receptor into the nuclei by 5-azacytidine.

[Hemoglobin A1 in hypoglycemias in childhood]. / Hämoglobin A1 bei Hypoglykämien im Kindesalter.

The average HbA1 concentrations of 20 patients with hypoglycaemic diseases were not significantly different from metabolically healthy controls. There was also no correlation between the HbA1 and the blood glucose levels of these patients. Remarkably, two patients which responded to therapy with an increase of blood glucose showed also an increase of HbA1.

Biochemical and clinical observations in four patients with fructose-1,6-diphosphatase deficiency.

Three boys and one girl suffering from inherited fructose-1,6-diphosphatase (FDPase) deficiency are reported. All four patients had less than 25% residual hepatic FDPase activity. While in two out of three patients the enzyme deficiency was also expressed in leucocytes, one patient had a normal enzyme activity. Remarkably, three patients had pronounced neonatal hyperbilirubinaemia requiring exchange transfusion.

[N-procollagen(III)peptide and lysosomal beta-galactosidase in progressive scleroderma and silicosis]. / N-Prokollagen(III)peptid und lysosomale beta-Galactosidase bei progressiver Sklerodermie und Silikose.

The concentration of type III collagen aminopropeptide and the activity of lysosomal beta-galactosidase were determined in the serum of patients with progressive sclerosis (PS), silicosis and PS associated with silicosis. In PS-patients, the serum levels of both parameters were significantly increased with a high correlation to the stage of the disease and to each other. In patients with silicosis normal serum concentrations of both parameters were found, whereas in all patients suffering from silicosis and PS significantly elevated serum levels were detectable, independent of the stage of PS. Both parameters can also be used as markers of therapy (e.g. with D-penicillamine) and as early indicators for the development of PS in patients with silicosis.

Influence of the placenta on fetal plasma insulin and neonatal hepatic enzyme induction in the rat.

In order to study the placental role in controlling glucose metabolism and neonatal induction of tyrosine aminotransferase in rat liver, a comparison was made between the artificially delivered-rat feto-placental unit and the newborn littermates. The immunoreactive serum insulin in the feto-placental unit remains as high as in utero for at least 1 h whereas in the newborn rat it decreases rapidly after delivery. From Caesarian section to 6 h later, in contrast to the newborn littermates, the feto-placental unit remains hyperglycaemic. Upon glucagon injection the feto-placental unit shows a delay in the increase of the hepatic tyrosine aminotransferase activity in comparison with the newborn rat.

Changes of glycogen phosphorylase isozyme pattern, in rat tissues during pre- and postnatal development.

Quantitative estimates of M- and L-type phosphorylase subunits in adult and developing rat tissues have been obtained by immunotitration of tissue extracts with subunit-specific antibodies. It has been shown that M-type subunits occur in all studied tissues with exception of adult liver and placenta. L-type subunits account for most of the total phosphorylase activity in liver and bone marrow but are present also in a variety of other adult and in most of the fetal tissues examined. During maturation, selective increases in the expression of phosphorylase isozymes occur in certain tissues such as liver, brain, heart and skeletal muscle. The hitherto unknown hybrid LM has been produced by in vitro hybridization of M- and L-subunits.

Interaction of adrenal and pancreatic hormones in the control of hepatic enzymes during development.

In the liver of suckling rats, the synthesis of hepatic tyrosine aminotransferase, serine dehydratase, and phosphofructokinase 2 as well as of renal beta-glucosidase is controlled by the circulating concentrations of adrenal and pancreatic hormones. Glucagon is capable of stimulating enzyme synthesis only in the presence of a steroid hormone. Dexamethasone and estradiol have been found to exert a permissive function on the inducibility of the studied enzymes by glucagon. Between the hormones of the adrenal medulla and glucagon antagonistic effects in enzyme induction were observed. Obviously, this antagonism is mediated by the alpha 1-adrenergic signal transferring system. A characteristic age dependence of enzyme induction by dexamethasone has been established. This might be correlated to alterations in the degree of methylation of the respective promoters. The methylation inhibitor 5-azacytidine influences significantly the enzyme induction by glucocorticoid hormones.

Effect of prenatal insulin and glucagon injection on the glycogen content of rat placenta and fetal liver.

The placental glycogen content per g wet weight decreases after the 16th day of gestation but remains nearly constant till the 21st day of gestation when expressed per placenta as whole organ. Injection of insulin to rat fetuses at the 21st day of gestation gives rise to hypoglycemia and an increase of the glycogen content in liver and in placenta. Intrauterine glucagon application makes fetuses hyperglycemic in consequence of a mobilization of the placental glycogen stores. Hepatic glucose production appears in later stages because of the low activity of glucose 6-phosphatase as demonstrated by the effect of glucagon on the hepatic glucose 6-phosphate concentration.

Origin of the enhanced activity of lysosomal beta-galactosidase in serum and skin in progressive systemic sclerosis.

In 14 patients with progressive systemic sclerosis (PSS) the activities of acid lysosomal glycosidases (alpha-, beta-galactosidase, beta-glucosidase, beta-glucuronidase, and beta-N-acetyl-glucosaminidase) were determined fluorometrically in serum, leukocytes, and skin tissue. The beta-galactosidase was the only enzyme which exhibited a significantly elevated activity in PSS serum and skin but not leukocytes, as compared to the control. The activity patterns of the studied glycosidases in serum were similar to those found in skin, but differ from the distribution of glycosidase activities in leukocytes. In cultured dermal fibroblasts derived from PSS patients, an elevated intracellular activity of beta-galactosidase was detected. These results suggest that the increased beta-galactosidase activity in the serum originates from the skin fibroblasts.

Glycogen phosphorylase isozyme pattern in rat liver and isolated non-parenchymal liver cells.

The isozyme distribution of glycogen phosphorylase (EC 2.4.1.1) was studied in adult rat liver and isolated non-parenchymal liver cells by means of immuno-titration. In adult rat liver, the L-type of glycogen phosphorylase was found to dominate, whereas the heterogeneous non-parenchymal liver cell population apparently contains all three glycogen phosphorylase isozymes.