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Biomedical subjects

M Pietsch

Publications and source records attributed to M Pietsch.

At least 55 records · Page 3Linked to original sources
PubMed1996

[Implantable catheter systems. Experiences with 1000 patients with central venous ports].

OBJECTIVE: To assess retrospectively duration of functioning and rate of complications of a totally implantable venous access system used for long-term chemotherapy. PATIENTS AND METHODS: Between 1985 and 1993, a central venous access system (Port-a-Cath) had been implanted subcutaneously for long-term chemotherapy in 1000 patients (479 males, 521 females; mean age 49 [15-86] years). Follow-up observations lasted until the end of the chemotherapy or the removal of the system. RESULTS: Mean time of functioning of the catheter system was 284 (2-1563) days. The complication rate was 12.8%: catheter infection in 4.9% and catheter thrombosis in 3.2%. A further 4.7% of patients had less common complications (malfunction, catheter dislocation, skin necrosis, catheter break or disconnection, pneumothorax). A total of 119 (11.9%) systems had to be removed because of complications. The rates of infection and of other complications were significantly lower in patients with solid tumours (2 and 4%, respectively) than in those with haematological disease (6 and 8%) (P < 0.05 for each). CONCLUSION: Totally implantable venous access systems are suitable for long-term chemotherapy and cause few complications.

Adolescent↗
PubMed1996

Altered inotropism in the failing human myocardium.

Beta-adrenoreceptor-cAMP-dependent inotropic interventions lose their effectiveness depending on the degree of myocardial failure. This blunted effect of beta-adrenoreceptor-dependent stimulation might be due to a downregulation of beta-adrenoreceptors and an increase of inhibitory G-proteins leading to decreased intracellular cAMP-concentrations. However, the maximal positive inotropic effect elicited by elevation of the extracellular [Ca2+] does not differ between failing and nonfailing human myocardium, indicating that terminally failing human myocardium is effective to increase force of contraction to the same degree as nonfailing tissue. Agents which increase force of contraction primarily via increasing the intracellular [Na+], e.g., cardiac glycosides and the Na(+)-channel activator BDF 9148, exert a higher potency in failing myocardium than in nonfailing tissue to increase force of contraction. This could result from an enhanced protein expression of the Na+/Ca(2+)-exchanger observed in diseased human hearts. Alterations in the intracellular Ca(2+)-homeostasis reported in failing myocardium lead to a negative force-frequency-relationship and a prolonged relaxation. As the protein expression of SERCA IIa and phospholamban seems to be similar in NYHAIV and nonfailing tissue, the reduced Ca(2+)- uptake may result from an altered regulation of these proteins, e.g., reduced phosphorylation of phospholamban or the SERCA IIa. After inhibition of the Ca(2+)-ATPase of the sarcoplasmic reticulum with the high specific inhibitor cyclopiazonic acid the former positive force-frequency-relationship became significantly less positive even in the nonfailing tissue and twitch course became similar to diseased hearts. These findings may be indicative for the importance of the Ca(2+)-reuptake mechanism into the sarcoplasmic reticulum in addition to the regulatory control at the site of the contractile apparatus for the regulation of contraction and relaxation in human myocardium.

Adrenergic beta-Agonists↗
PubMed1996

Deficits in selective and sustained attention processes in early treated children with phenylketonuria--result of impaired frontal lobe functions?

UNLABELLED: Twenty normally intelligent children with early treated phenylketonuria (PKU) (IQ: mean = 101.4, SD = 10.0; age: mean = 10 years 11 months, SD = 1.3 years) and 20 healthy controls, matched for age, sex and IQ, were assessed for their selective (Stroop Task) and sustained attention (Test-d-2). Using positron emission tomography an activation of the frontal lobe during the Stroop task had previously been demonstrated. In addition to the Stroop Task and the Test-d-2, a short-term memory test as a "non-frontal-lobe-function-task" was administered to all subjects. Group comparisons demonstrated that PKU children had specific deficits in selective and sustained attention, which were significantly correlated with the concurrent serum phenylalanine concentration. CONCLUSION: The results give evidence that even dietary treated children with PKU were suffering from impaired attentional control mechanisms in spite of a normal IQ. The deficits might be the result of impaired frontal lobe functions.

Adolescent↗
PubMed1996

Untreated non-phenylketonuric-hyperphenylalaninaemia: intellectual and neurological outcome.

The intellectual, neurological, and neuropsychological outcome of patients with non-phenylketonuric-hyperphenylalaninaemia (PKU-HPA) (serum phenylalanine levels under free diet < 600 mumol/l) has not been systematically studied so far. We therefore tested 28 patients (mean age = 21.8, SD = 4.2 years) for IQ (WAIS-R/WISC-R), school performance, job career, clinical neurological examination, fine motor performance (motor performance task), and selective and sustained attention (stroop task, Dot Pattern Exercise from the Sonneville visual attention task). In addition, cranial MRI (1.5 T unit) was obtained in 10 of these patients. Clinical-neurological examination revealed no significant abnormalities in the non-PKU-HPA patients. They also had a normal IQ (mean = 101.9, SD = 13.6). Compared to their healthy siblings, they attended a normal school and had a normal job career. The motor performance task revealed no deficits in fine motor abilities. The patients performed normally in the stroop task and the dot pattern exercise. Their MRIs were normal. Our results indicate that patients with non-PKU-HPA are not at risk for developing intellectual, neurological, and neuropsychological impairment, as described for patients with treated mild or classical phenylketonuria. From this point of view a dietary treatment is not necessary in patients with hyperphenylalaninaemia.

Adolescent↗
PubMed1996

Effect of L-dopa on visual evoked potentials and neuropsychological tests in adult phenylketonuria patients.

Eight adult, untreated patients with classical phenylketonuria received L-dopa and a decarboxylase inhibitor for 2 weeks. No effect of L-dopa therapy on choice reaction time tasks, sustained attention, frontal lobal function as well as latencies of visual evoked potentials was found. The results raise the question if adult patients with phenylketonuria really suffer from functional dopamine deficiency.

Adult↗
PubMed1996

Sustained attention in untreated non-PKU-hyperphenylalaninemia.

Twenty-four untreated adolescent and adult patients with non-PKU hyperphenylalaninemia (HPA) (serum Phe levels < 600 mumol/L) and 24 healthy controls matched for age, sex, and IQ were investigated for simple motor reaction time and sustained attention, which are prolonged in patients with mild or classical phenylketonuria (PKU). Patients with HPA were of normal intelligence and did not differ significantly from healthy controls in their test results. For HPA patients, reaction times and sustained attention were not significantly influenced by serum phenylalanine concentrations. We conclude that dietary treatment is not necessary in patients with non-PKU HPA.

Adolescent↗
PubMed1996

No fine motor deficits in patients with untreated non-phenylketonuria hyperphenylalaninaemia.

Twenty-four untreated adolescent and adult patients with non-phenylketonuria (PKU) hyperphenylalaninaemia (HPA) (serum phenylalanine levels < 600 mumol l-1) and 24 healthy controls matched for age, sex and IQ were investigated for their neurological outcome, especially for fine motor abilities by the Motor Performance Task. No pathological findings could be revealed by clinical neurological examination. Patients with HPA and healthy controls did not significantly differ in their fine motor performances. These performances were not significantly influenced by serum phenylalanine concentrations. Our results indicate that untreated patients with non-PKU HPA are not at clinically significant risk for developing fine motor deficits and severe neurological impairment. From this point of view a dietary treatment is not necessary in patients with HPA, as recommended most recently.

Adolescent↗
PubMed1996

[Effect of administration of blood products on the course of tetanus antibody concentration in immuno-incompetent patients].

OBJECTIVE: Collecting of data for immunoprophylaxis of tetanus in immunodeficient patients via administration of blood products. DESIGN: Prospective single case studies. SETTING: Clinical therapy in a department of hematology with continuous determination of tetanus antibody concentrations in patients' sera and administered blood products with an enzyme immunoassay. PATIENTS: 3 patients with acute myeloid leukemia (FAB classifications M1, M3, M4). INTERVENTIONS: Regular administration of blood products due to clinical therapy. RESULTS: After administration of about 4,000 IU tetanus antitoxin i.v., serum concentration is increasing by 1 IU/ml. Half life in serum amounts to 7 days. Protection lasts therefore up to 6 weeks. CONCLUSIONS: Immunodeficient patients may receive a medium-term effective protection against tetanus after selection of suitable blood products. This method is interesting also for prophylaxis of postoperative tetanus in immunocompetent patients.

Antibodies, Bacterial↗
PubMed1995

Tetanus immunization and its association to hepatitis B vaccination in patients with chronic renal failure.

A defect in the immune response of patients with chronic renal failure leads to low response rates and insufficient antibody concentrations following a number of highly recommended vaccinations. This has been shown before for immunization against hepatitis B and influenza. Few data are available concerning the efficacy of vaccination with tetanus toxoid in these patients. In a prospective, controlled study we vaccinated seronegative patients with chronic renal failure not on dialysis, patients on chronic intermittent hemodialysis, and patients after kidney transplantation with tetanus toxoid. The results were compared with those of a control group consisting of 13 age-matched patients with mild essential hypertension and normal kidney function. Only 11 of 20 (55%) patients in the chronic renal failure group and 16 of 23 (69%) in the dialysis group had a protective antibody response after triple vaccination. In contrast, all the patients in the control group and six of seven transplant patients seroconverted. The response to tetanus toxoid was highly associated with the response to a previously administered vaccination against hepatitis B. Responders to this vaccination also had a better response rate to tetanus toxoid. The antibody concentrations after vaccination were lower in all patient groups compared with the controls; the lowest titers were found in the transplant patients. Therefore, renal patients will need revaccination much earlier, and tetanus toxoid antibody levels should be checked if a patient is injured and potentially requires vaccination.

Adult↗
PubMed1995

Neurological findings in early treated phenylketonuria.

Twenty early treated, normal intelligent patients (IQ: mean 101.4, SD 10.0; age: mean 10.11, SD 1.3 years) with classical phenylketonuria and 20 age-, sex- and IQ-matched healthy controls were investigated for neurological outcome, especially with regard to fine motor ability using the motor performance task ("Motorische Leistungsserie"). No pathological findings were seen on clinical neurological examination. The patient group had significantly poorer results in a concentration task (Test-d-2) as well as in some subtests of the motor performance task. Patients had difficulties in tasks which needed speed and precision of arm-hand-finger movements. High serum phenylalanine concentrations were significantly correlated with these deficiencies in fine motor ability. Our data demonstrated mild neurological impairment even in early and relatively strictly treated patients with phenylketonuria.

Attention↗
PubMed1994

Regioselective synthesis of new sucrose derivatives via 3-ketosucrose.

3-Ketosucrose (alpha-D-ribo-hexopyranosyl-3-ulose-beta-D-fructofuranoside), obtained from sucrose via microbial oxidation with Agrobacterium tumefaciens, was shown to be an appropriate and versatile synthon for regioselective syntheses. Condensation with hydroxylamine and its derivatives with allyl and benzyl groups leads to the oxime and the corresponding substituted products. By reductive amination 3-amino-3-deoxy-alpha-D-allopyranosyl-beta-D-fructofuranoside is obtained which can readily be submitted to further functionalization to methacryloyl and fatty acid derivatives. After silylation of 3-ketosucrose the 3-allyl and butylene-substituted as well as decyl- and dodecyl-substituted sucrose can be obtained via Grignard reaction, the side chains being C-C linked to the saccharide.

Carbohydrate Conformation↗
PubMed1994

Cranial MRI in PKU: evaluation of a critical threshold for blood phenylalanine.

A group of 15 adolescent patients with PKU and good life time blood phenylalanine control was tested for white matter abnormalities on MRI. Five of the patients presented mild to moderate abnormalities in association with blood phenylalanine levels above 5.0 mg/dl. Patients with and without MRI changes could statistically not be discriminated by blood phenylalanine concentrations at the time of investigation as well as by phenylalanine levels of different time periods prior to MRI examination.

Adolescent↗
PubMed1993

[The status of maternally acquired tetanus immunity in newborn infants].

In newborn and their mothers a considerable lack of immunity to tetanus was found. Values of corresponding serum pairs differed in part; some children were unprotected in spite of maternal immunity. Pregnant women without protection should therefore be vaccinated twice before delivery. Over and above this, good hygienic standards in obstetrics must be maintained.

Antibodies, Bacterial↗