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H Schulz

Publications and source records attributed to H Schulz.

At least 73 records · Page 4Linked to original sources
PubMed2001

[Measurement of the Fowler dead space in patients with pulmonary emphysema using C18O2].

In patients with lung emphysema, changes in lung volumes as well as changes in airway resistance are well known. The change in airway resistance is caused by obstruction of central airways, which is supposed to reduce the respiratory dead space. Until now, it was not possible to measure the respiratory dead space in patients with lung emphysema using the method of Fowler [2], because in this method distinction of the three phases of an inert gas expirogram is essential. While this distinction is easy in healthy subjects (fig. 1; expirogram 3), the separation of the three phases in patients with lung emphysema is not possible due to gradual transition of phase II into phase III in these patients (fig. 1; expirogram 2). The use of C18O2 as tracer gas allows to separate phase II and phase III even if the patients have severe emphysema (fig. 1; expirogram 1). CO2 labeled with the stable oxygen isotope 18O (C18O2) is completely taken up in the gas exchanging region of the lung, but not from the conducting airways. Therefore C18O2 is only expired from the dead space of the lung, but not from the alveolar region. Hence, C18O2 allows exact measurement of the respiratory dead space in patients with lung emphysema. 21 healthy nonsmoking subjects and 29 patients with clinical signs of lung emphysema participated in this study. There was a good correlation between respiratory dead space, measured by the use of Ar-gas and C18O2-gas in healthy subjects (fig. 2). This indicates, that the use of C18O2 is a valid method to measure the functional dead space. As expected, there was also a correlation between the airway resistance and respiratory dead space in patients with lung emphysema (fig. 3), but not in healty subjects. There was no significant difference of the mean values of the respiratory dead space between these two groups (223 +/- 43 ml in healthy subjects vs. 227 +/- 52 ml in patients), even though there were large differences in airway resistance (0.20 +/- 0.10 kPa/l/s vs. 0.49 +/- 0.27 kPa/l/s). This may be due to a loss of alveolar function in the area of the terminal bronchioli, which is typical for emphysematous patients. This entails a shift of functional dead space towards lung periphery and therefore causes an increase of the volume of functional dead space. But this enlargement may be compensated by the volume reduction, caused by the airway obstruction. Hence, these two oppositional mechanisms may result in only minimal change of dead space volume.

Adult↗
PubMed2001

Radioimmunoassay for N-terminal probrain natriuretic peptide in human plasma.

Measurement of plasma levels of natriuretic peptides has been used to assess left ventricular dysfunction and prognosis. Recently levels of the N-terminal peptide fragment of the precursor of brain natriuretic peptide have been reported to be present in peripheral plasma and to be increased in chronic heart failure patients. Our aim in this study was to develop a radioimmunoassay for N-terminal proBNP, to compare its plasma concentrations in control subjects and in patients with end-stage heart failure and to define its relation to brain natriuretic peptide (BNP). A polyclonal antibody was raised in rabbits against human N-terminal proBNP fragment (amino acid 1-21). The plasma N-terminal proBNP concentrations were assayed directly without extraction. No detectable cross-reactivity existed with other natriuretic peptides: BNP, ANP or N-terminal proANP. The assay had a detection limit (2 SD from zero) of 9.7 pmol/L. Plasma N-terminal proBNP was 29 (13-75) (median (range)) pmol/L in the control group. There were no gender difference, male: 28 (13-61) vs. female 33 (13-75) pmol/L, p= NS, but there was a positive correlation to age (r=0.52, p<0.0001). In patients with end-stage heart failure the median N-terminal proBNP levels were increased significantly 616 (114-2781) pmol/L (p<0.001) and in pooled data N-terminal proBNP showed a close correlation to BNP (r=0.96, p<0.0001). Size exclusion of plasma extracts indicated that proBNP (1-108) may circulate both as intact prohormone and as split products, N-terminal proBNP (1-76) and BNP (77-108). Our results support the concept that N-terminal proBNP measurement could be a valuable tool in the biochemical indication of increased cardiac wall stress.

Adult↗
PubMed2001

Impulse oscillometry in healthy nonsmokers and asymptomatic smokers: effects of bronchial challenge with methacholine.

The clinical application of respiratory impedance measurements by oscillation techniques for monitoring bronchial challenge testing is hampered by the fact that data in healthy nonsmokers and asymptomatic smokers are very limited. The objective of this study was to analyze the changes in impedance to a methacholine provocation test in healthy nonsmokers and asymptomatic smokers, and to investigate whether smokers show a different response compared to nonsmokers. The response to methacholine challenge was assessed by impulse oscillometry (IOS) (resistance R and reactance X at 5, 10, 15, 20, 25, and 35 Hz) and spirometry (FEV1, MEF50) in 105 healthy subjects (55 nonsmokers: "NS"; 50 asymptomatic smokers: "S") in whom the provocation dose of 2.44 mg methacholine did not result in a fall of FEV1 below 20% predicted of the baseline value. The baseline reactance X values of S were significantly lower compared to NS from 10 to 35 Hz (p < or = 0.01), whereas S and NS did not differ in resistance R over the whole frequency spectrum from 5 to 35 Hz. S showed a significantly higher mean baseline resonant frequency X(f0); i.e., the frequency at which inertial forces are equal and opposite to elastic forces, compared to NS (NS: X(fo) = 10.8+/-2.9 Hz; S = 12.6+/-4.0 Hz, p = 0.01). In both groups methacholine challenge resulted in an increase in R (f) especially at 5 and 10 Hz, and a marked decrease in X(f) over the whole frequency spectrum. In S a significantly higher decrease of postchallenge X5Hz and X10Hz was measured compared to NS (NS: deltaX(5Hz) = -0.044+/-0.003; S: deltaX(5HZ) = -0.083+/-0.013; p = 0.0017. NS: deltaX(10Hz) = -0.050+/-0.001; S: deltaX(10Hz) = -0.082+/-0.017; p = 0.008). R and X at low frequencies showed a three to four times higher postchallenge reaction compared to FEV1. Pre- and postchallenge FEV1 did not correlate with resistance R (f) and reactance X(f) over the whole frequency spectrum. In S perchallenge X(f) values from 10 to 35 HZ were significantly lower, and postchallenge decrease of X5Hz and X10Hz values were significantly higher compared to that of NS, whereas pre- and postchallenge R(f) values were similar in both groups. These results can be explained by changes in the elastic properties of the lung induced by a diffuse subclinical respiratory bronchiolitis.

Adult↗
PubMed2001

(99m)Tc-E-selectin binding peptide for imaging acute osteomyelitis in a novel rat model.

INTRODUCTION: In the present study, (99m)Tc-radiolabelled E-selectin binding peptide ((99m)Tc-IMP-178) was investigated for its potential to image acute pyogenic osteomyelitis in a new animal model. Intraindividual comparisons were performed using an irrelevant peptide ((99m)Tc-IMP-100) to demonstrate specificity. METHODS: An acute pyogenic osteomyelitis was induced by injecting 0.05 ml of 5% sodium morrhuate and 5x10(8) CFU of Staphylococcus aureus into the medullary cavity of the right tibia in 16 rats. Sixteen additional rats served as untreated controls. Whole-body imaging of pyogenic (n=4) and untreated (n=4) animals was performed continuously during the first 8 h (12 MBq i.v. of (99m)Tc-IMP-178 and (99m)Tc-IMP-100 for control), and one further single image was acquired after 16 h p.i. Tissue biodistribution studies were performed in 12 rats with an acute pyogenic osteomyelitis and in 12 untreated rats 1, 4 and 24 h after injection. Data of the histological/radiological and haematological investigations were obtained in all animals. RESULTS: Histopathologically, 15 of 16 treated rats (93%) developed an acute pyogenic osteomyelitis showing a major infiltration of the bone marrow by polymorphonuclear leukocytes as well as the formation of sequestra. Haematologically, the number of leukocytes increased by 100%, the lymphocytes by 11% and the granulocytes decreased by 39%. After i.v. injection, (99m)Tc-IMP-178 rapidly cleared from the body resulting in good scintigraphic target-to-background (T/B) ratios. The highest uptake of the tracer in the pyogenic bone was observed at 60 min p.i. (0.43+/-0.02% ID.g-1 for (99m)Tc-IMP-178 and 0.30+/-0.02% ID.g-1 for (99m)Tc-IMP-100), resulting in a higher osteomyelitis-to-healthy collateral ratio with T/B of 2.40+/-0.65 ((99m)Tc-IMP-178) compared with 1.85+/-0.48 ((99m)Tc-IMP-100). No adverse reactions were seen after injection of (99m)Tc-IMP-178. CONCLUSIONS: (99m)Tc-IMP-178 allows imaging of an acute osteomyelitic lesions, presumably by interaction of (99m)Tc-IMP-178 with activated upregulated vascular endothelium.

Acute Disease↗
PubMed2001

Expression analysis using oligonucleotide microarrays in mice lacking bradykinin type 2 receptors.

We recently conducted detailed cardiovascular and blood pressure-related phenotypic studies of mice lacking the bradykinin-B(2) receptor and were unable to identify a phenotype despite insensitivity to infused bradykinin. We therefore used oligonucleotide microarray analysis of some 12 000 genes and expressed sequence tags to identify molecular mechanisms that might be involved in compensating for the lack of a functional B(2) receptor in the kidneys of the mice. We identified 2 gene families that may have an impact on cardiovascular regulation and the bradykinin pathway. A water transport channel in the kidney, AQP4, was downregulated in the mice, whereas other members of the gene family did not show differences in expression levels. In addition, a number of serine proteases were upregulated in B(2) receptor-deficient mice. These genes are all located within a gene cluster on mouse chromosome 7. The findings were verified by an independent method. We suggest that microarray analysis has usefulness in elucidating otherwise unappreciated compensatory signaling pathways.

Animals↗
PubMed2001

Disease specific quality of life instruments in multiple sclerosis: validation of the Hamburg Quality of Life Questionnaire in Multiple Sclerosis (HAQUAMS).

Quality of life (QoL) is discussed as an additional outcome measure in multiple sclerosis (MS). However, few questionnaires assessing disease specific QoL in MS have been published. On the basis of the literature and interviews with clinicians and MS patients, we have developed a disease specific QoL instrument and validated it in a broad range of patients with MS. In this study, a heterogeneous sample of n = 237 MS patients completed the newly developed Hamburg Quality of Life Questionnaire in Multiple Sclerosis (HAQUAMS, in German language) and a battery of already validated questionnaires. They further underwent neurological scoring and objective tests. By these means, we investigated its validity, appropriateness, internal consistency, and retest reliability. Internal consistency and retest coefficients were high and satisfied psychometric standards. Convergent and discriminant validity was supported by direction, magnitude and pattern of correlations with other health measures. HAQUAMS subscales and its total score distinguished between patient groups of varied disease severity, cognitive impairment, and affective symptomatology. No floor or ceiling effects were found in either of the HAQUAMS subscales. The HAQUAMS is a reliable, valid and appropriate instrument for QoL assessment in multiple sclerosis. Data of responsiveness are currently being obtained.

Adult↗
PubMed2001

Pulmonary and systemic distribution of inhaled ultrafine silver particles in rats.

The cardiovascular system is currently considered a target for particulate matter, especially for ultrafine particles. In addition to autonomic or cytokine mediated effects, the direct interaction of inhaled materials with the target tissue must be examined to understand the underlying mechanisms. In the first approach, pulmonary and systemic distribution of inhaled ultrafine elemental silver (EAg) particles was investigated on the basis of morphology and inductively coupled plasma mass spectrometry (ICP-MS) analysis. Rats were exposed for 6 hr at a concentration of 133 microg EAg m(3) (3 x 10(6) cm(3), 15 nm modal diameter) and were sacrificed on days 0, 1, 4, and 7. ICP-MS analysis showed that 1.7 microg Ag was found in the lungs immediately after the end of exposure. Amounts of Ag in the lungs decreased rapidly with time, and by day 7 only 4% of the initial burden remained. In the blood, significant amounts of Ag were detected on day 0 and thereafter decreased rapidly. In the liver, kidney, spleen, brain, and heart, low concentrations of Ag were observed. Nasal cavities, especially the posterior portion, and lung-associated lymph nodes showed relatively high concentrations of Ag. For comparison, rats received by intratracheal instillation either 150 microL aqueous solution of 7 microg silver nitrate (AgNO(3) (4.4 microg Ag) or 150 microL aqueous suspension of 50 microg agglomerated ultrafine EAg particles. A portion of the agglomerates remained undissolved in the alveolar macrophages and in the septum for at least 7 days. In contrast, rapid clearance of instilled water-soluble AgNO(3) from the lung was observed. These findings show that although instilled agglomerates of ultrafine EAg particles were retained in the lung, Ag was rapidly cleared from the lung after inhalation of ultrafine EAg particles, as well as after instillation of AgNO(3), and entered systemic pathways.

Administration, Inhalation↗
PubMed2001

Bullying and victimization of primary school children in England and Germany: prevalence and school factors.

Differences in definitions and methodologies for assessing bullying in primary school children between countries have precluded direct comparisons of prevalence rates and school factors related to bullying. A total of 2377 children in England (6-year-olds/Year 2: 1072; 8-year-olds/Year 4: 1305) and 1538 in Germany (8-year-olds/Year 2) were questioned individually using an identical standard interview. In both countries the types of bullying to victimize others were similar: boys were most often perpetrators, most bullies were also victims (bully/victims), most bullying occurred in playgrounds and the classroom, and SES and ethnicity only showed weak associations with bullying behaviour. Major differences were found in victimization rates with 24% of English pupils becoming victims every week compared with only 8% in Germany. In contrast, fewer boys in England engaged every week in bullying (2.5-4.5%) than German boys (7.5%), while no differences were found between girls. In England, children in smaller classes were more often victimized. Further study of the group of bully/victims, schooling differences in England vs. Germany and implications for prevention of bullying are discussed.

Aggression↗
PubMed2001

Interleukin 16 expression in relation to disease activity in rheumatoid arthritis.

OBJECTIVE: Rheumatoid arthritis (RA) is a chronic inflammatory disease of unknown etiology characterized by an infiltration of CD4+ T lymphocytes within the rheumatoid synovium. Cytokines have been shown to play a modulatory role in the pathogenesis of RA. We analyzed the expression of a T cell derived cytokine. interleukin 16 (IL-16), in relation to disease activity to characterize its biologic function in RA. METHODS: Secreted IL-16 was measured by enzyme immunoassay in sera and synovial fluids (SF) from 25 patients with RA in comparison to 20 control samples from patients with osteoarthritis (OA). IL-16 expression in peripheral blood mononuclear cells (PBMC) was characterized by flow cytometric analysis after intracellular cytokine staining for IL-16. In synovial tissue specimens, IL-16 mRNA expression was analyzed by real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR). In parallel, expression of IL-16 was localized in synovial tissues by in situ hybridization and immunohistochemistry. Results were analyzed in relation to disease activity. RESULTS: IL-16 was detected at significantly higher levels in sera and SF of patients with RA in comparison to OA (p < 0.001). Flow cytometry of PBMC showed that a great proportion of both CD4+ and CD8+ T cells constitutively expressed the IL-16 protein. In synovial tissues, IL-16 mRNA levels were significantly elevated in comparison to OA controls (p < 0.001). In situ hybridization for IL-16 producing cells revealed a predominant accumulation of IL- 16 positive cells within the inflammatory infiltrates. A significant correlation between IL- 16 expression and local inflammatory activity could not be established (r = 0.27, p = 0.19) by microscopic analysis of the synovial cell infiltrate. In addition, no significant association was observed between serum, SF, and synovial tissue expression of IL-16 and clinical disease activity in RA. CONCLUSION: These data suggest IL-16 might play a role in the pathogenesis of chronic inflammation in RA. The lack of significant correlation between IL-16 expression, clinical disease activity, and local inflammatory activity suggests a regulatory rather than a proinflammatory function for IL-16 in the pathogenesis of chronic synovial inflammation in RA.

Adult↗
PubMed2001

[Treatment of the neurological sleep disorders restless legs syndrome and narcolepsy].

Pharmacological therapies are presented for two typical neurological sleep-wake disorders, restless legs syndrome (RLS) and narcolepsy. The individual discomfort caused by RLS and the accompanying problems with initiating and maintaining sleep often require a therapy with L-dopa and dopamine agonists. Positive treatment effects on sensory and motor symptoms have been shown in open trials and controlled studies. Development of time shift and/or augmentation of symptoms is a problem of L-dopa therapy. Further efficient drugs are opioids and benzodiazepines. The therapy of narcolepsy depends on its severity and the pattern of the symptoms. Excessive daytime sleepiness and sleep attacks are the most impairing symptoms, which are difficult to treat. These symptoms require an optimal combination of CNS stimulants with regular napping. Cataplexy and other REM sleep associated symptoms are effectively treated with REM sleep suppressing antidepressants.

Anti-Anxiety Agents↗
PubMed2001

[Diagnosis and classification of sleep disorders].

When sleep was recognized as an active process which is regulated by the interaction of homeostatic and circadian systems a new understanding of sleep disturbances set in, and sleep medicine developed as a new medical speciality. An internationally recognized classification system was developed which allows to diagnose the different sleep disturbances reliably. Sleep disorders comprise (a) dysregulations of the sleep-wake system (insomnias, hypersomnias, narcolepsy, parasomnias), (b) sleep associated disturbances of functional systems (for example sleep apnea, restless legs syndrome), (c) disturbances of the circadian sleep-wake rhythm, and (d) sleep disturbances in association with other organic or psychiatric illnesses. The present contribution shows the diagnostic procedures for four main sleep disorders, namely insomnia, obstructive sleep apnea (OSAS), restless legs syndrome (RLS), and narcolepsy.

Circadian Rhythm↗
PubMed2000

CCME, a nuclear-encoded heme-binding protein involved in cytochrome c maturation in plant mitochondria.

The maturation of c-type cytochromes requires the covalent attachment of the heme cofactor to the apoprotein. For this process, plant mitochondria follow a pathway distinct from that of animal or yeast mitochondria, closer to that found in alpha- and gamma-proteobacteria. We report the first characterization of a nuclear-encoded component, namely AtCCME, the Arabidopsis thaliana orthologue of CcmE, a periplasmic heme chaperone in bacteria. AtCCME is targeted to mitochondria, and its N-terminal signal peptide is cleaved upon import. AtCCME is a peripheral protein of the mitochondrial inner membrane, and its major hydrophilic domain is oriented toward the intermembrane space. Although a AtCCME (Met(79)-Ser(256)) is not fully able to complement an Escherichia coli CcmE mutant strain for bacterial holocytochrome c production, it is able to bind heme covalently through a conserved histidine, a feature previously shown for E. coli CcmE. Our results suggest that AtCCME is important for cytochrome c maturation in A. thaliana mitochondria and that its heme-binding function has been conserved evolutionary between land plant mitochondria and alpha-proteobacteria.

Amino Acid Sequence↗
PubMed2000

Capillary electrophoresis with laser-induced fluorescence in clinical drug development routine application and future aspects.

The clinical bioanalytical setting is characterized by sample volumes of < 1 ml biological fluid (e.g. plasma, urine), a range of 3-4 decades of concentrations to be quantified and a limit of quantitation in the microg/l-ng/l range for sets of 100-5000 individual samples. Setup of capillary electrophoresis (CE) for routine application in this analytical field was successful for analytes accessible to fluorescence detection by using laser-induced fluorescence (LIF) detection. Empowerment of CE-LIF for routine serial analysis of thousands of samples includes improvement in autosampler techniques, thorough procedures for capillary treatment and particularly more advanced detection technology. Introduction of multi-capillary systems with charge-coupled device cameras and frequency doubled Ar-ion laser (lambda = 257 nm) offers this technique the chance of superiority over classical analytical assays - especially in the field of (new) low volume samples e.g. capillary blood or microdialysate encouraging clinicians to search for meaningful non-invasive samples.

Anti-Infective Agents↗
PubMed2000

Assay of tramadol in urine by capillary electrophoresis using laser-induced native fluorescence detection.

Capillary electrophoresis (CE) with UV laser-induced native fluorescence detection was developed as a sensitive and selective assay for the direct determination of tramadol in human urine without extraction or preconcentration. The main problem in CE is the small inner diameter of the capillary which causes a low sensitivity with instruments equipped with a UV detector. Laser-induced native fluorescence with a frequency doubled argon ion laser at an excitation wavelength of 257 nm was used for the direct assay of tramadol in urine to enhance the limit of detection about 1,000-fold compared to UV absorption detection. The detection system consists of an imaging spectrograph and an intensified CCD camera, which views an illuminated 1.5 mm section of the capillary. This set-up is able to record the whole emission spectra of the analytes to achieve additionally wavelength-resolved electropherograms. In the concentration range of 20 ng/ml-5 microg/ml in human urine coefficients of correlation were better than 0.998. Within-day variation determined on four different concentrations showed accuracies ranging from 90.2 to 108.4%. The relative standard deviation (RSD) was determined to be less than 10%. Day-to-day variation presented accuracies ranging from 90.9 to 103.1% with an RSD less than 8%.

Analgesics, Opioid↗
PubMed2000

2,4-Dienoyl-CoA reductase from Escherichia coli is a novel iron-sulfur flavoprotein that functions in fatty acid beta-oxidation.

2,4-Dienoyl-CoA reductase is an enzyme that is required for the beta-oxidation of unsaturated fatty acids with even-numbered double bonds. The 2,4-dienoyl-CoA reductase from Escherichia coli was studied to explore the catalytic and structural properties that distinguish this enzyme from the corresponding eukaryotic reductases. The E. coli reductase was found to contain 1 mol of flavin mononucleotide and 4 mol each of acid-labile iron and sulfur in addition to 1 mol of flavin adenine dinucleotide per mole of protein. Redox titrations revealed a requirement for 5 mol of electrons to completely reduce 1 mol of enzyme and provided evidence for the formation of a red semiquinone intermediate. The reductase caused a significant polarization of the substrate carbonyl group as indicated by an enzyme-induced red shift of 38 nm in the spectrum of 5-phenyl-2,4-pentadienoyl-CoA. However, suspected cis --> trans isomerase and Delta(3),Delta(2)-enoyl-CoA isomerase activities were not detected in this enzyme. It is concluded that the 2, 4-dienoyl-CoA reductases from E. coli and eukaryotic organisms are structurally and mechanistically unrelated enzymes that catalyze the same type of reaction with similar efficiencies.

Escherichia coli↗
PubMed2000

Genome search for susceptibility loci of common idiopathic generalised epilepsies.

Genetic factors play a major role in the aetiology of idiopathic generalised epilepsies (IGEs). The present genome scan was designed to identify susceptibility loci that predispose to a spectrum of common IGE syndromes. Our collaborative study included 130 IGE-multiplex families ascertained through a proband with either an idiopathic absence epilepsy or juvenile myoclonic epilepsy, and one or more siblings affected by an IGE trait. In total, 413 microsatellite polymorphisms were genotyped in 617 family members. Non-parametric multipoint linkage analysis, using the GeneHunter program, provided significant evidence for a novel IGE susceptibility locus on chromosome 3q26 (Z(NPL) = 4.19 at D3S3725; P = 0.000017) and suggestive evidence for two IGE loci on chromosome 14q23 (Z(NPL) = 3.28 at D14S63; P = 0.000566), and chromosome 2q36 (Z(NPL) = 2.98 at D2S1371; P = 0.000535). The present linkage findings provide suggestive evidence that at least three genetic factors confer susceptibility to generalised seizures in a broad spectrum of IGE syndromes. The chromosomal segments identified harbour several genes involved in the regulation of neuronal ion influx which are plausible candidates for mutation screening.

Chromosomes, Human, Pair 14↗