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Biomedical subjects

R Holzer

Publications and source records attributed to R Holzer.

16 recordsLinked to original sources
PubMed2004

The impact of cardiopulmonary bypass on selenium status, thyroid function, and oxidative defense in children.

Selenium has important functions for oxidative defense and thyroid hormone metabolism. Selenium-dependent enzymes include 5'-iodothyronine deiodinase and glutathione peroxidase (GPX). The objective of this study was to investigate the relationship between plasma selenium, GPX activity, and thyroid hormone status in pediatric cardiac surgical patients. Plasma concentrations of selenium, free triiodothyronine (fT3), free thyroxin (fT4), and c-reactive protein as well as plasma activity of GPX were prospectively evaluated at anesthetic induction and 48 hours postoperatively in 59 children requiring cardiopulmonary bypass (CPB). GPX was measured at additional time points at 6, 12, and 24 hours postoperatively. There was a significant reduction in the plasma selenium concentration after cardiopulmonary bypass with obtained median measurements of 0.61 micromol/L (induction) and 0.51 micromol/L (48 hours postoperatively). The fT3/fT4 ratio decreased significantly from 0.28 at anesthetic induction to 0.22 at 48 hours postoperatively. There were no significant changes of GPX activity. 48 hours fT3 concentration, fT3/fT4 ratio, and selenium concentration were significantly negatively correlated with the time spent in intensive care. The concentration of plasma selenium in children undergoing cardiopulmonary bypass significantly decreases, resulting in diminished deiodinase activity, and a subsequent reduction in the conversion of T4 to T3.

Adolescent↗
PubMed2002

Congenital heart disease and neuroblastoma: just coincidence?

The clinical history of a neonate with simple transposition of the great arteries in whom a metastatic neuroblastoma was diagnosed incidentally at autopsy is described, and the literature containing all 66 previously reported cases of neuroblastoma associated with congenital cardiac malformations is reviewed. One third of the described cases were classified as in situ neuroblastoma; neural crest derived cardiac lesions were present in 31%. Several possible aetiological mechanisms are discussed, and we conclude that the association of neuroblastoma with congenital cardiac malformations is multifactorial in origin. The described case represents the first reported example in which catecholamine release may have contributed to the fatal outcome of definitive congenital cardiac surgery.

Adrenal Gland Neoplasms↗
PubMed2001

Polyimide-based microfluidic devices.

This paper describes the development of polyimide-based microfluidic devices. A layer transfer and lamination technique is used to fabricate flexible microfluidic channels in various shapes and with a wide range of dimensions. High bond strengths can be achieved by cure cycle adaptation and surface treatment of the polyimide layers prior to bonding. The polyimide microchannels can be combined with metallization layers to fabricate electrodes inside and outside channels. The resulting devices can be used for flexible fluidic and electrical connectors, implantable fluid delivery devices, microelectrodes with embedded fluidic channels, chip-based flow cytometry and for a great variety of other applications in medical, chemical or biological research.

Journal Article↗
PubMed2001

Similar efficacy following four weeks treatment of asthmatics with formoterol 12 micrograms b.d. delivered by two different dry powder inhalers: differences in inhaler handling.

This randomised, multicentre, parallel-group study compared the clinical efficacy and ease of handling of two dry powder inhalers delivering the long-acting beta 2-agonist formoterol. After run-in, 200 asthmatics on treatment with inhaled corticosteroids and still presenting with suboptimal asthma control were randomised to receive 12 micrograms formoterol twice daily via either the Aerolizer inhaler (Foradil Aerolizer) or the Turbuhaler inhaler (Oxis Turbuhaler) for four weeks. Study variables included the mean morning pre-medication peak expiratory flow (PEF) during the last seven days of treatment and the correct inhaler handling according to inhaler-specific checklists. The mean difference in the effect on morning pre-medication PEF was 13.86 l/min in favour of formoterol via the Aerolizer inhaler (90% confidence interval 2.50, 25.21) in the intent-to-treat population. Eighty-six per cent of the patients under treatment with formoterol via the Turbuhaler inhaler performed correctly all the essential inhalation manoeuvres, whereas 98% of those on the Aerolizer inhaler did so. These results strongly suggest similar clinical efficacy with twice daily treatment of formoterol 12 micrograms metered dose delivered either by the Aerolizer, or the Turbuhaler device. They also suggest that handling the Aerolizer is easier than that of the Turbuhaler.

Administration, Inhalation↗
PubMed1999

Quantitative determination of polycyclic aromatic hydrocarbons, polychlorinated biphenyls and organochlorine pesticides in sewage sludges using supercritical fluid extraction and mass spectrometric detection.

Supercritical CO2 extraction (SFE) proved to be a valuable, fast, quantitative and partly selective extraction technique for determining polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and chlorinated pesticides (OCPs) in sewage sludges of different catchment areas based on a comparison study with certified reference materials (CRMs) and on recovery data. Most PCB extracts could be measured directly after SFE whereas for PAHs a short clean-up improved the final separation by high-resolution capillary gas chromatography. Due to the amount of coextracted compounds and the low levels of OCPs, extracts obtained by SFE had to be submitted to a multistep clean-up for final measurement. Average concentrations of 6.9 mg/kg dry mass (dm) for the sum of the 16 Environmental Protection Agency PAHs, 0.1 mg/kg dm for the sum of the seven PCB congeners and 0.002-0.072 mg/kg dm for the OCPs were found in the sewage sludges. Compared to studies performed earlier in our laboratory PAHs are still present in similar concentrations whereas PCB levels have decreased significantly. OCPs could be detected in only low amounts. A correlation between sludge type and degree of contamination could only be found for PAHs.

Chromatography↗
PubMed1996

Comparison of high resolution gas chromatography with electron impact and negative ion mass spectrometry detection for the determination of coplanar polychlorobiphenyl congeners in sewage sludges.

The three most toxic coplanar PCB 77, 126 and 169 have been identified and quantified at ultra trace levels (0.02-4.8 ng/gdw) in swiss sewage sludge samples applying high resolution capillary gas chromatography (HRGC) and electron impact (EI) as well as negative ion chemical ionization (NCI) mass spectrometry (MS). NCI mass spectra have been dominated by the molecular ion as base peak and virtually no fragmentation has been observed. Detection limits of the planar PCB under single ion monitoring (SIM) conditions have been typically 100 fg for NCI-MS and 1 pg for EI-MS. NCI-MS was the preferred detection method for the determination of very low concentrations of these important contaminants in sewage sludge samples.

Journal Article↗
PubMed1993

Evaluation of fluticasone propionate (500 micrograms day-1) administered either as dry powder via a Diskhaler inhaler or pressurized inhaler and compared with beclomethasone dipropionate (1000 micrograms day-1) administered by pressurized inhaler.

Five hundred and eighty-five patients with moderate asthma, currently receiving 400-1000 micrograms day-1 of an inhaled corticosteroid, were treated for 6 weeks in a double-blind, randomized, parallel group study with either 500 micrograms day-1 fluticasone propionate as a dry powder via a Diskhaler inhaler, 500 micrograms day-1 fluticasone propionate via a pressurized inhaler or 1000 micrograms day-1 beclomethasone dipropionate via a pressurized inhaler. For all three treatment groups, mean morning and evening peak expiratory flow rates (PEFRs) increased within 1 week of the start of treatment. There were also improvements in clinic lung function, daytime and night-time asthma symptoms and a reduction in daytime and night-time rescue bronchodilator medication in all three groups. There were no statistically significant differences between the two formulations of fluticasone propionate in any of the efficacy parameters. Fluticasone propionate via the Diskhaler was significantly more effective than beclomethasone dipropionate over the 6 week study period in reducing diurnal variation (mean difference--4 l min-1, 95% CI--8 to 0 l min-1: P = 0.03). Fluticasone propionate via the Diskhaler produced a statistically significant improvement in night-time symptoms when compared to beclomethasone dipropionate whereas, beclomethasone dipropionate 1000 micrograms day-1 was statistically significantly more effective than both formulations of fluticasone propionate in improving daytime symptoms (P < 0.05). However, these statistical differences must be viewed together with the fact that very few patients recorded a score of 2 or more for both daytime or night-time symptoms. There was a similarly low incidence of adverse events with all three treatments with no evidence of hypothalamic pituitary adrenal (HPA)-axis suppression. The results of the 6-week comparative study showed that 500 micrograms day-1 fluticasone propionate whether administered via pressurized inhaler or Diskhaler is as effective and as safe as 1000 micrograms day-1 beclomethasone dipropionate administered via a pressurized inhaler in the treatment of moderate asthma. Over 12 months fluticasone propionate 500 micrograms day-1 via a pressurized inhaler was at least as effective and as well tolerated as beclomethasone dipropionate 1000 micrograms day-1.

Adolescent↗
PubMed1993

[Comparison of two long-acting theophylline preparations in daily evening administration].

The therapeutic value of a sustained-release theophylline preparation (Theospirex retard 300 mg) with administration of the daily dose once a day in the evening compared to the 2 x 1 dosage usual was investigated in 19 patients suffering from asthma symptoms manifested mainly at night. In this open randomized clinical trial, a sustained-release theophylline preparation (400 mg) which had already been used for administration once a day in the evening served as reference preparation. The single dose in the evening for both preparations was 600 mg pure theophylline. Target parameters were the level of theophylline in the blood, the pulmonary function, symptoms of asthma, and the tolerance of the two sustained-release drugs. The theophylline serum levels after 13 respectively 22 hours were 12.44 and 6.98 micrograms/ml for the reference drug and 11.72 and 7.11 micrograms/ml for Theospirex retard. Equivalence of the two drugs was shown in the parameters pulmonary function, symptoms of asthma and tolerance. This study shows that 300 mg Theospirex retard film-coated tablets are suitable for a single administration of the entire daily dose in the evening.

Adult↗
PubMed1992

[The time requirement for endoscopic diagnosis and therapy: results of a multicenter study].

For evaluation of the time requirements for endoscopic diagnostic and therapeutic procedures data of 13,321 patients gathered from 155 endoscopic units were collected. Time requirements were calculated for preparation of the procedure, examination and after-care of patients and instruments. The data indicate, that time requirement is significantly influenced by the special procedure. Therefore, calculation of the time requirement of an individual unit needs exact consideration of the frequency of different procedures. Only cleaning of instruments by washing machines could be shown to reduce time requirement. Education of endoscopists was demonstrated to be time intensive. Age (exemption children) sex of patients and video-endoscopy did not effect duration of procedures.

Adolescent↗
PubMed1982

[Mediastinitis and bilateral pleural effusion of pancreatic origin (author's transl)].

A case report is presented of a patient admitted to a thoracic specialist unit on account of predominantly pulmonary symptomatology. There was a left-sided haemorrhagic pulmonary effusion, which rapidly returned after tapping. The patient then developed a high fever and shock. Mediastinal widening was noted on X-ray, as well as a right-sided pleural effusion. Repeated tapping of the pleural effusions and drainage of a mediastinal abscess, which was diagnosed on mediastinoscopy as well as the administration of antibiotics led to an improvement in the patient's previously poor general condition. Sonography and subsequent endoscopic retrograde pancreatography were instrumental in eventually diagnosing chronic recurrent pancreatitis with cyst formation and retroperitoneal perforation into the mediastinum and pleural space. Laparotomy with removal of the pancreatic cysts and abdominal drainage led to complete recovery. The pathogenetic processes involved in the formation of internal fistulae, diagnostic problems and therapeutic management are discussed.

Adult↗
PubMedDate not supplied

Idiopathic multifocal intracardiac and pulmonary thrombosis: successful treatment with rTPA.

A 21-month-old boy with respiratory symptoms for one month secondary to idiopathic multichamber intracardiac and pulmonary thrombosis is presented who was successfully treated with recombinant tissue plasminogen activator (rTPA). The etiology and risk factors of pediatric intracardiac thrombosis are discussed and the literature and all reported cases are reviewed. It is important to consider cardiopulmonary thrombosis as a differential diagnosis of respiratory distress in childhood.

Coronary Thrombosis↗