Search PubMed⌕ Search

Biomedical subjects

J Schaub

Publications and source records attributed to J Schaub.

At least 37 records · Page 2Linked to original sources
PubMed2000

Magnesium balance studies in premature and term infants.

BACKGROUND: The knowledge of magnesium requirements of premature infants is still very limited, although it is essential for the optimal composition of suitable formulas. AIM OF THE STUDY: The study concept was 1) to assess physiological magnesium balance data of healthy term infants and longitudinal results from formula-fed premature infants and 2) to deduce conclusions on the magnesium content of the formulas. METHODS: Premature infants (n = 14, birth weight < or = 1500 g, gestational age < or = 32 weeks) were studied in conventional balance trials with 1) a semi-elemental diet (A), 2) preterm infant formula (B), and 3) infant formula (C). In addition, healthy term formula-fed (n = 11, D) and breast-fed (n = 14, E) infants were investigated. Analysis was performed by flame atomic absorption spectroscopy. RESULTS: The median magnesium intake ranged between 4.84 mg/kg x d-1 (breast-fed infants) and 16.33 mg/kg x d-1 (premature infants). The term breast-fed infants retained nearly as much magnesium as term formula-fed infants (3.37 vs. 3.97 mg/kg x d-1), due to a low percental fecal and urinary excretion. A higher magnesium retention was observed in the premature group: A: 7.97 mg/kg x d-1, B: 5.3 mg/kg x d-1, 3.) C: 5.54 mg/kg x d-1. CONCLUSION: In view of the high percental magnesium retention in formula-fed premature infants, excessive supply should be avoided. The long-term effects of lower intakes have to be monitored.

Bottle Feeding↗
PubMed2000

Molybdenum supplementation in phenylketonuria diets: adequate in early infancy?

BACKGROUND: Molybdenum concentrations in formulas exceed those in human milk by far. Infants with phenylketonuria require semisynthetic phenylalanine-restricted diets. Because these diets are presently supplemented with molybdenum, a study was conducted to determine whether retention and plasma concentration in the recipients are equivalent to those of healthy breast-fed infants. METHODS: Balance and plasma studies were conducted in healthy breast-fed infants (n = 17) and in patients with phenylketonuria (n = 4) at the age of 4 weeks, and the plasma investigations were repeated at the ages of 4 and 12 months. The samples were analyzed by atomic absorption spectroscopy (balance studies) and high-resolution inductively coupled plasma mass spectrometry (plasma). RESULTS: Molybdenum intake and retention in all infants with phenylketonuria were more than 18 times those of breast-fed infants. The plasma concentrations reflected these differences. A median of 0.04 microg/l was assessed in breast-fed infants at 4 weeks and less than 0.02 microg/l at 4 months of age. Comparative results of infants with phenylketonuria were 2.9 microg/l and 2.5 microg/l, respectively. There were no significant differences between the groups at 12 months of age. CONCLUSIONS: The phenylketonuria diets investigated showed excessive retention and plasma concentrations of the essential trace element molybdenum in early infancy. In view of these findings, the present practice of molybdenum fortification should be revised.

Bottle Feeding↗
PubMed1999

Stem cell factor influences neuro-immune interactions: the response of mast cells to pituitary adenylate cyclase activating polypeptide is altered by stem cell factor.

Mast cells degranulation can be elicited by a number of biologically important neuropeptides, but the mechanisms involved in mast cell-neuropeptide interactions have not been fully elucidated. Stem cell factor (SCF), also known as c-kit or kit ligand, induces multiple effects on mast cells, including proliferation, differentiation, maturation, and prevents apoptosis. We investigated the ability of SCF to affect mast cell responsiveness to the neuropeptides pituitary adenylate cyclase activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP). PACAP 1-27, PACAP1-38, or VIP failed to induced preformed mediator release from mouse bone-marrow-cultured mast cells (BMCMC) derived in concanavalin A-stimulated spleen conditioned medium (CM). By contrast, BMCMC grown in SCF-containing medium or freshly isolated peritoneal mast cells exhibited significant 3H-hydroxytrypamine (5-HT) release in response to PACAP peptides or VIP. Deoxyglucose and the mitochondrial inhibitor antimycin significantly inhibited PACAP-induced 5-HT release indicating that the central event induced by PACAP peptides was exocytosis. The G(alpha)i inhibitor, pertussis toxin, significantly diminished PACAP-induced 5-HT release from BMCMCs in SCF suggesting the involvement of heterotrimeric G-proteins. Western blot analysis using antibodies directed against the human VIP type I/PACAP type II receptor demonstrated a 70-72 kD immunoreactive protein expressed in greater amounts in BMCMC grown in SCF compared with BMCMC in CM. We conclude that SCF induces a mast cell population that is responsive to PACAPs and VIP involving a heterotrimeric G-protein-dependent mechanism.

Animals↗
PubMed1998

Fanconi-Bickel syndrome--the original patient and his natural history, historical steps leading to the primary defect, and a review of the literature.

UNLABELLED: Fanconi-Bickel syndrome (FBS) is a rare autosomal recessive disorder of carbohydrate metabolism recently demonstrated to be caused by mutations in Glut2, the gene for the glucose transporter protein 2 expressed in liver, pancreas, intestine and kidney. The disease was first described in a 3-year-old Swiss boy in 1949. Here we report a follow up of this original patient over more than 50 years and show that the typical clinical and laboratory findings of FBS (hepatomegaly secondary to glycogen accumulation, glucose and galactose intolerance, fasting hypoglycaemia, a characteristic proximal tubular nephropathy and severe short stature) persist into adulthood. We further summarize the historical observations that eventually led to the identification of the basic defect of FBS and give an overview of the 82 cases from 70 families in the published literature and from personal communications. CONCLUSION: Although with the first description of a congenital defect of facilitative glucose transport the main steps in the pathophysiology of Fanconi-Bickel syndrome have been elucidated, numerous pathophysiological mechanisms are far from clear and thus encourage the ongoing study of patients with this disorder.

Child, Preschool↗
PubMed1997

The identification of hyperoxaluria in very low-birthweight infants--which urine sampling method?

The present study was performed to determine the best method of urine collection for measurement of oxalate excretion in very low-birthweight (VLBW) infants and to verify the utility of the oxalate/creatinine ratio in VLBW infants. This has not been investigated in this group with developing renal function. In a prospective study of 30 VLBW infants, we compared oxalate excretion in urine collected over 24 h and in a spot urine sample. The urinary oxalate concentration was measured by the oxalate oxidase method. The correlation coefficient between the amount of oxalate per kilogram body weight excreted daily and the oxalate/creatinine ratio in spot urine sample was 0.80 (P < 0.0001) and with the oxalate/creatinine ratio in a 24-h urine collection 0.82 (P < 0.0001). The two highest levels of oxalate excretion (> 100 mumol/kg per day) were detected with both oxalate/creatinine ratios (> 1 mmol/ mmol). No circadian rhythm of oxalate excretion was found. The measurement of the oxalate/creatinine ratio in spot urine samples is suitable for screening VLBW infants for hyperoxaluria.

Circadian Rhythm↗
PubMed1997

Mutations in GLUT2, the gene for the liver-type glucose transporter, in patients with Fanconi-Bickel syndrome.

Fanconi-Bickel syndrome (FBS) is a rare autosomal-recessive inborn error of metabolism characterized by hepatorenal glycogen accumulation, Fanconi nephropathy and impaired utilization of glucose and galactose. To date, no underlying enzymatic defect in carbohydrate metabolism has been identified. Therefore, and because of the impairment of both glucose and galactose metabolism, a primary defect of monosaccharide transport across membranes has been suggested. Here we report mutations in the gene encoding the facilitative glucose transporter 2 (GLUT2) in three FBS families, including the original patient described in 1949 by Fanconi and Bickel. Homozygous mutations were found in affected individuals, whereas all parents tested were heterozygous for the respective mutation. Because all detected mutations (delta T446-449, C1251T and C1405T) predict truncated translation products that cannot be expected to have functional monosaccharide transport activity, GLUT2 mutations are probably the cause of FBS.

Consanguinity↗
PubMed1997

Oxalate excretion during the first 7 weeks in very-low-birth-weight infants.

To determine reference values, we studied urinary excretion of oxalate prospectively and longitudinally in a cohort of 23 very-low-birth-weight (VLBW) infants. The urinary oxalate concentrations were evaluated in 24-hour urine samples by the oxalate oxidase method. Urine samples were obtained at 1, 2-3, 4-5 and 6-7 weeks of age. The median oxalate amount was 24 mumol/kg body weight/day with a 10th-90th percentile range of 16-45 in the 1st week. Oxalate excretion was highest in 2- to 3-week-old infants (median: 35; percentile range: 26-56 mumol/kg body weight/day). In the 4th-5th week, the median was 24 (percentile range: 15-47) mumol/kg body weight/day and in weeks 6-7 also 24 (percentile range: 10-36) mumol/ kg body weight/day. Also, the urinary oxalate concentration as well as the oxalate-creatinine ratio showed increased values in the first 3 weeks of life and decreased values afterwards. In a multivariate analysis, nutrition or gestational age did not affect the urinary oxalate concentration, the daily amount excreted or the oxalate-creatinine ratio. The investigated parameters (oxalate amount and oxalate-creatinine ratio in urine) were significantly age dependent). The data show that urinary oxalate excretion in VLBW infants approaches levels that are in the same range as those of patients with urolithiasis. Thus the risk of nephrocalcinosis in VLBW infants may be increased.

Age Distribution↗
PubMed1996

Precast commercial polyacrylamide gels for separation of DNA amplificates by temperature gradient gel electrophoresis: application to clonality analysis of lymphomas.

The third complementary determining region (CDR-III) of the rearranged immunoglobulin heavy chain (IgH) genes represents a unique marker for a lymphocyte and its clonal descendants and can be amplified by the polymerase chain reaction (PCR) technique. This approach has markedly enhanced the sensitivity for detection of clonal lymphocyte populations in patients with malignant B-lymphoid neoplasias. To monitor minimal residual disease (MRD) in tissue specimens during or after antineoplastic treatment, the problem of detecting the presence of a few clonal (malignant) lymphocytes in coexistence with a majority of polyclonal lymphocytes has to be addressed. Semi-nested PCR amplification of CDR-III rearrangements from specimen infiltrated by tumor cells generates clonal signals in front of a polyclonal background, and therefore high resolution electrophoretic techniques for separation of DNA fragments are required. Temperature gradient gel electrophoresis (TGGE) resolving DNA homo- and heteroduplexes according to their thermal stability has been successfully applied for this purpose using special electrophoretic equipment. We describe an adjustment to this technique by using a commercially available precast 0.5 mm thick polyacrylamide gel and by changing a standard horizontal electrophoretic device into a TGGE device. By this means we screened patients with B-cell lymphoma undergoing high-dosage radiochemotherapy followed by autologous transplantation for continuous presence of clonal (tumor-specific) CDR-III rearrangements. Specimens from blood and bone marrow were collected on diagnosis as well as before and after autologous transplantation. In addition, the autograft (bone marrow or peripheral blood hematopoietic stem cells) was analyzed. Tumor cells were easily detected in the transplants and in specimens collected during follow-up examinations. The clinical value of these findings remains unclear as yet because the number of cases investigated was small and the follow-up time is still too short. However, we conclude that the technique of combining the sensitivity of PCR with the specificity of high resolution TGGE is easy to use, making it possible to handle, in a clinical routine, a great number of samples within a short time in order to monitor MRD in patients with B-cell neoplasias.

Cell Transplantation↗
PubMed1996

Cerebrospinal fluid concentrations of leukotriene B4 in bacterial meningitis.

We investigated whether leukotriene B4 (LTB4), a granulocyte inflammatory mediator, is detectable in cerebrospinal fluid using a high performance liquid chromatographic method. In non-pleocytotic cerebrospinal fluid (n = 5) and in cerebrospinal fluid from children with aseptic meningitis (n = 8), LTB4 concentrations were below the detection limit (< 0.2 ng ml-1). In the range 0-20 ng ml-1, the recovery rate of LTB4 that had been added to non-pleocytotic cerebrospinal fluid was > 90%. In cerebrospinal fluid with a polymorphonuclear leucocyte (PMN) count higher than 1,000/ml, LTB4 was detectable in six out of seven specimens with a concentration of 0.35-3.3 ng ml-1. LTB4 concentration was significantly correlated with PMN number. These results, together with observations in animal models, are discussed with regard to a pathophysiological role of LTB4 in bacterial meningitis.

Child↗
PubMed1994

Natural history of body mass index in Williams-Beuren syndrome.

Body mass index (BMI) is a useful tool for the investigation of obesity or underweight. It follows a typical pattern throughout childhood. During the first few years of life underweight due to feeding problems and gastrointestinal disturbances is considered a common sign in Williams-Beuren syndrome (WBS), whereas obesity is frequently reported in WBS adults. Systematic studies on weight gain and body mass index in WBS do not exist. Therefore, we studied weight gain relative to height expressed as BMI in 82 WBS girls (459 measurements of weight and height) and in 104 WBS boys (562 measurements). At birth BMI was significant lower in WBS than in normal infants in both sexes (P < 0.0001). During the first months of life, mean BMI showed a catch-up from the 3rd to the 10th-50th centiles in WBS infants relative to the normal standards. The further course of BMI was almost parallel to normal development. In addition, a gradual relative increase to the 50th centile of normal was seen in both sexes. In conclusion, weight gain during the first year of life was sufficient. Feeding and gastrointestinal problems seem not to have a severe impact on weight gain in infancy. Until adulthood weight relative to height continuously reached the 50th centile of normal. Thus, obesity is not a common finding in young adults with WBS. The results of this study may serve as a disease-specific reference of BMI development in WBS patients.

Abnormalities, Multiple↗