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Biomedical subjects

D Michalk

Publications and source records attributed to D Michalk.

At least 37 records · Page 2Linked to original sources
PubMed1994

Protecting effect of taurine against hypoxic cell damage in renal tubular cells cultured in different transplant preservation solutions.

We conclude that, within this experimental model and under these experimental conditions, taurine supplementation of standard kidney preservation solutions improves survival of kidney cells during hypoxic preservation. The protective effect depends on the taurine concentration, the hypoxic preservation time and the used preservation solution. Physiological taurine concentrations are effective during short hypoxic periods, whereas pharmacological taurine concentrations seem to be needed for longer periods of hypoxia. Within this experimental model University of Wisconsin solution seems to be more effective than Euro collins solution.

Animals↗
PubMed1994

The determination of ultrasound velocity in the os calcis, thumb and patella during childhood.

Maximising the accumulation of bone tissue during growth and puberty is one of the most important aims in the prevention of osteoporosis. For prevention studies in children it is necessary to develop methods for skeletal status without radiation. Ultrasonic velocity (speed of sound = SOS) has been proposed as an alternative method. Using a new ultrasonic system (Osteoson K4, Minhorst, Germany), we investigated the reproducibility and age-dependency of SOS in several peripheral bones in 218 children and young adults. Intra-observer (day to day) reproducibility: calcaneus CV = 0.64%, patella CV = 1.18% and thumb CV = 0.43% (n = 25). Inter-observer reproducibility: calcaneus CV = 1.1%, patella CV = 2.48% and thumb CV = 0.62% (n = 16). SOS in thumb and patella increased with age and peaked at 20-25 years. SOS in the calcaneus showed no increase after puberty. Studies in bones from pigs show no dependency of SOS from the thickness of analysed cortical or trabecular bone slices. We conclude that the reproducibility of SOS measurements especially in the thumb is comparable with those of radiation methods. The SOS data in growing, healthy children and the independency from bone dimensions provides more evidence that SOS describes the elastic qualities of the bones.

Adolescent↗
PubMed1993

Holocarboxylase synthetase deficiency: early diagnosis and management of a new case.

We present a new case of holocarboxylase synthetase (HCS) deficiency, a rare autosomal recessive metabolic disorder, causing the "early-onset" form of multiple carboxylase deficiency. The patient was born at term of healthy consanguineous parents after an uncomplicated pregnancy. On the 2nd day of life she refused oral feeding, became tachydyspnoeic and showed excessive weight loss. Laboratory studies showed metabolic acidosis, marked lactic acidaemia, hyperammonaemia and increased urinary excretion of 3-hydroxyisovaleric acid, 3-methylcrotonylglycine, 3-hydroxpropionic acid and methylcitric acid. Peritoneal dialysis combined with oral supplementation of biotin (10 mg/day) started on the 3rd day of life resulted in rapid clinical recovery and normalisation of biochemical parameters. HCS deficiency was established in lymphocytes and skin fibroblasts. The activities of all biotin-dependent carboxylases were severely decreased in fibroblasts grown in medium with moderate biotin concentration (10(-8) mol/l) but normal in a high biotin medium (10(-5) mol/l). Mitochondrial carboxylase activities in lymphocytes were 23%-29% of mean normal during therapy with 20 mg of biotin/day, with the higher dose of 40 mg/day they were within (3-methylcrotoryl-CoA carboxylase, pyruvate carboxylase) or slightly below (propionyl-CoA carboxylase) the normal range. At the age of 3 years the patient's physical and psychomotor development are normal. Early biotin supplementation should be considered in newborns with lactic acidosis and organoaciduria until a final diagnosis has been established. Furthermore, the required individual dose of biotin has to be carefully evaluated biochemically for the individual patient.

Biotin↗
PubMed1992

Psychosocial adaptation of children and adolescents with chronic renal failure.

In a multicentre study comprising five paediatric nephrology centres in Western Germany, psychosocial and educational parameters were assessed (during 1987) in 479 children and adolescents with chronic renal failure (CRF) in order to gain insight into their psychosocial adaptation to the disease. At the time of assessment, 31% of patients were on conservative treatment, 14% on haemodialysis, 9% on continuous ambulatory peritoneal dialysis and 46% had a functioning transplant. The mean age at assessment was 13.6 years. Additional disabilities were noted in 29% of patients. School attendance of the 233 children of school age was in general satisfactory; 22% of patients attended schools for disabled or handicapped children. Vocational training was frequently inadequate, especially for dialysed patients, and only 14 of 53 adolescents over 16 years had graduated. Of 49 adult patients, only 21 were in some form of employment. A lack of age-appropriate independence was observed in a large proportion (86%) of patients over 17 years, who continued to live with their parents or other persons taking care of them, whilst only 14% were living alone or with a partner. We conclude that, despite improved survival, psychosocial adaptation continues to be impaired in paediatric patients with CRF, especially in adolescents and those on dialysis.

Adaptation, Psychological↗
PubMed1991

[Effect of L-carnitine supplementation on lipid metabolism of renal failure, dialysis-dependent children and adolescents].

In six renally insufficient children and adolescents (age: 8-21 years) on hemodialysis the effect of L-carnitine supplementation at two dose levels (10 mg/kg/d vs. 100 mg/kg/d) on parameters of lipid metabolism was investigated. L-Carnitine substitution was carried out over four weeks per dose level. Under this regime a significant increase of the serum carnitine concentration occurred together with a decrease in the AC/FC-ratio (x: 1.59 to x:0.83). During the same period a significant decrease in serum triglyceride levels as well as an increase in serum HDL-cholesterol were observed. An inverse correlation (r = -0.63; p less than 0.0008) was found between HDL-cholesterol and the AC/FC-ratio. L-carnitine supplementation and its increasing effect on HDL-cholesterol in patients with renal insufficiency may be considered as antiatherogenic.

Adolescent↗
PubMed1990

Particulate (high-molecular-mass) and soluble alkaline phosphatase in urine determined by high-performance liquid chromatography.

We detected in urine by HPLC two enzyme fractions of alkaline phosphatase (AP, EC 3.1.3.1), soluble and particulate, analogous to those in serum. The second fraction was eluted with high-salt-content eluent at the same elution time as high-molecular-mass, or particulate, AP in serum. AP characterization in urine from a patient with acute rejection crisis showed a greater sensitivity of the particulate form to treatment with L-phenylalanine, which suggests a higher content of intestinal-type AP in the particulate form. The soluble fraction showed a more liver-type AP behavior. Changes in the chromatograms after the sample was treated with 1-butanol and Triton X-100 support a membrane origin of the particulate AP. Urinalyses from patients with acute renal disease showed increased activity of soluble and particulate AP, with a relatively greater increase of particulate AP.

Adult↗
PubMed1989

[Kidney involvement in infectious diseases].

Involvement of the kidneys without direct invasion of them by the pathogenic agents has been recognized in a variety of infections with bacteria, viruses, fungi, and protozoa. Pathogenetic importance attaches to immune mechanisms with formation and glomerular deposition of immune complexes, or direct damage caused to the renal parenchyma by microbial toxins. Signs and symptoms may range from minimal proteinuria and/or microhematuria, through nephritic or nephrotic syndrome, to acute or chronic renal failure. Accordingly, all kinds of glomerulonephritis or interstitial nephritis may be found on histological examination. With rapid elimination of the causative agent the prognosis is generally good.

Child↗
PubMed1988

[Acute recurrent pancreatitis as the main symptom of lupus erythematosus disseminatus in childhood].

A 17 year old girl with chronic relapsing pancreatitis since the age of 11 developed focal seizures, leukopenia, anemia and thrombozytopenia, signs suggesting lupus erythematodes. All immunologic investigations, including tests for Anti-DNS-Antibodies were negative, however. Therapy with prednisone and azathioprine resulted in clinical remission. Reduction of the immunosuppression lead to a severe crisis, which was controlled by plasmaseparation and cyclophosphamide. Subsequent analysis of circulating immune complexes revealed bound anti-DNS-antibodies.

Acute Disease↗
PubMed1984

The effect of L-carnitine-supplemented total parenteral nutrition on tissue amino acid concentrations in piglets.

Miniature piglets underwent total parenteral nutrition (TPN) with and without L-carnitine supplementation during a 7-day period. Thereafter the tissue amino acid concentrations of liver, heart, skeletal muscle and brain were determined and compared to those of orally fed animals. The altered tissue amino acid concentrations during TPN without carnitine returned to normal when L-carnitine was supplemented. The most striking changes of tissue concentrations showed taurine in liver, muscle and brain and ethanolamine in heart and brain. In muscle the branched-chain amino acids were increased when L-carnitine was added to the TPN regime. Ethanolamine changes were discussed with respect to the position of this amino acid in the synthesis of phospholipids. The marked decrease of brain taurine concentrations after carnitine-free TPN was accompanied by reduced values for GABA. Both the substances function as inhibitory transmitters in the brain and should be considered when seizure activity in patients with systemic carnitine deficiency is discussed.

Administration, Oral↗
PubMed1983

Tissue carnitine concentrations after total parenteral nutrition with and without L-carnitine supplementation.

The concentrations (mumoles/g dry weight) of total carnitine (TC), free carnitine (FC) and acylcarnitine (AC) were determined in skeletal muscle, heart, liver, kidney and brain cortex of male mini pigs (4000-5000 g) after seven days of total parenteral nutrition (TPN) with amino acids 5% (3.0g/kg/d), glucose (25g/kg/d) and lipids 20% (4g/kg/d). This regime was administered with L-carnitine supplementation (1.5 mg/kg/d; n = 7) (group 1) and without it (n = 5) (group 2). Orally alimented animals (n = 5) served as controls (group 3). (Average carnitine intake: 3 mg/d) Carnitine free TPN affected only the concentrations in muscle. TC was markedly reduced (3.6 +/- 0.8) when compared with oral controls (5.8 +/- 0.7) (p<0.01). This decrease was exclusively due to AC, whereas FC concentrations remained almost unchanged. In group 1 the concentrations of TC in skeletal muscle, heart and brain cortex were higher than in both the other groups. The increase was mainly due to AC and FC remained unchanged in heart and brain. The concentrations in liver and kidney were not affected by either carnitine free or carnitine supplemented TPN. AC, determined as described, consists almost entirely of acid soluble acetyl-carnitine, the major product of fatty acid oxidation. Since the AC concentrations were almost exclusively altered by the two TPN-regimes we conclude that the observed changes reflect regulatory changes of fatty acid oxidation. Thus the decrease of muscle TC in group 2 is considered a consequence of an insulin induced down regulation (plasma insulin: mean 20 muU/ml; maximum: 60 muU/ml) of fatty acid oxidation in consequence of high glucose intake (25 g/kg/d). The increased TC concentrations after carnitine supplemented TPN are discussed to reflect an enhancement of oxidative degradation of fatty acids as a pharmacological effect of L-carnitine.

Journal Article↗
PubMed1983

Survival time in cystinosis. A collaborative study.

In a retrospective study the overall survival time of 205 cystinotic patients of six countries was determined. The median survival time was 8.5 years. The median time for 'renal death' (age at death due to uraemia or age at starting renal replacement therapy) was 9.2 years. The youngest patient dying of renal death was 5.2 years. No sex difference in survival time was noticed. Furthermore no difference in survival time was noted between the different countries. The analysis of the overall survival curve indicates no clear differences between the infantile and adolescent types of cystinosis.

Adolescent↗
PubMed1982

Is there a risk for kidney stone formation in cystic fibrosis?

Patients with malabsorption syndromes have an increased risk of kidney stone formation. Those with cystic fibrosis (CF) suffer from extreme forms of steatorrhea, but they are not reported to be prone to kidney stone formation. Risk parameters for renal stone formation were studied in the urine of 43 patients with cystic fibrosis and compared to those of 5 patients with calcium oxalate nephrolithiasis and 21 healthy controls. Patients with CF showed increased urinary concentrations of oxalate, phosphate, xanthine and uric acid, and decreased concentrations of magnesium and citrate, comparable to concentrations found in patients with calcium oxalate stones. However, compared to stone bearing controls the calcium concentration was markedly decreased in the urine of CF patients. Our results suggest that hypocalciuria in CF seems to protect against nephrolithiasis despite the presence of lithogenic factors. Calcium supplementation instituted for clinical reasons may result in an increased risk for kidney stone formation. This risk may be diminished by additional administration of magnesium as well as allopurinol.

Adolescent↗
PubMed1982

Renal handling of inorganic sulfate in children with chronic kidney disorders.

Excretion, clearance and tubular reabsorption of inorganic sulfate (SO4) were measured in 38 children with various chronic kidney disorders over a wide range of glomerular filtration rates (GFR). The SO4 excretion remained constant up to advanced renal failure. Significant correlations were found between GFR and clearance or tubular reabsorption of SO4, respectively. It appears that in early renal insufficiency the reduction of tubular SO4 reabsorption is sufficient to prevent an increase in plasma SO4. At GFR values below 30 ml/min/1.73 m2 about half of the children studied exhibited a net tubular secretion of SO4 and all patients showed a rapid increase of plasma SO4 up to 10 times mean normal levels. It is suggested that the accumulation of SO4 in uremia is less compensated for than that of other ions.

Absorption↗