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Biomedical subjects

R Schmid

Publications and source records attributed to R Schmid.

At least 37 records · Page 2Linked to original sources
PubMed2004

Perfusion temperature during cardiopulmonary bypass does not affect serum S-100beta release.

BACKGROUND: The potentially harmful effects of normothermia on neurological outcome during cardiopulmonary bypass (CPB) are controversial. METHODS: In this study, we compared the early and late release patterns of S-100beta, a marker of cerebral injury, after normothermic and moderately hypothermic CPB. Forty-eight patients undergoing coronary artery bypass grafting were randomly assigned to either the normothermia (37 degrees C) or the hypothermia (32 degrees C) group. Serum S-100beta levels were measured until 24 h after CPB. Neurological examination was performed before and after surgery. RESULTS: With the exception of intraoperative blood glucose levels, there were no differences between groups. This also applied to peak S-100beta values (Gr-N: 3.5 +/- 1.9 microg/l; Gr-H: 3.5 +/- 3.4 microg/l) and values after 24 h (Gr-N: 0.32 +/- 0.16 microg/l; Gr-H: 0.35 +/- 0.28 microg/l). CONCLUSIONS: The similar pattern of S-100beta release without evident neurological complications in the normothermia group does not suggest an increase in cerebral injury during normothermic CPB.

Aged↗
PubMed2003

Efficacy of montelukast in the treatment of chronic obstructive pulmonary disease in five horses.

Five horses with moderate to severe chronic obstructive pulmonary disease (COPD) were treated with 0.11 (0.01) mg/kg bodyweight of montelukast, a cysteinyl leukotriene receptor antagonist, once a day for 26 days. The horses were evaluated clinically and endoscopically and subjected to arterial blood gas analysis and lung function tests before and after the period of treatment, and the plasma concentrations of montelukast were determined by high-performance liquid chromatography with fluorescence detection. The treatment did not result in statistically significant differences in the total scores of clinical and endoscopical signs, or in the difference in the arterioalveolar partial pressure of oxygen, maximal changes in pleural pressure, pulmonary resistance or dynamic compliance. The mean (sd) peak plasma concentration (C(max0) of montelukast was 12 (4) ng/ml and was reached 66 (13) minutes (t(max)) after its oral administration. The dose of montelukast per kg bodyweight was approximately the same as that for human beings, but the C(max) in the horses was 28 times lower and the t(max) was reached in one-fifth of the time, suggesting that its oral bioavailability may be lower.

Acetates↗
PubMed2003

[18F]FDG imaging of head and neck tumours: comparison of hybrid PET and morphological methods.

The aim of this study was to evaluate fluorine-18 fluorodeoxyglucose ([(18)F]FDG) imaging of head and neck tumours using a second- or third-generation hybrid PET device. Results were compared with the findings of spiral computed tomography (CT) and magnetic resonance imaging (MRI), and, as regards lymph node metastasis, the ultrasound findings. A total of 116 patients with head and neck tumours (83 males and 33 females aged 27-88 years) were examined using a hybrid PET scanner after injection of 185-350 MBq of [(18)F]FDG (Picker Prism 2000 XP-PCD, Marconi Axis gamma-PET(2) AZ). Hybrid PET examinations were performed in list mode using an axial filter. Reconstruction of data was performed iteratively. Ninety-six patients underwent CT using a multislice technique (Siemens Somatom Plus 4, Marconi MX 8000), 18 patients underwent MRI and 100 patients were examined by ultrasound. All findings were verified by histology, which was considered the gold standard, or, in the event of negative histology, by follow-up. Correct diagnosis of the primary or recurrent lesion was made in 73 of 85 patients using the hybrid PET scanner, in 50 of 76 patients on CT and in 7 of 10 patients on MRI. Hybrid PET successfully visualised metastatic disease in cervical lymph nodes in 28 of 34 patients, while 23 of 31 were correctly diagnosed with CT, 3 of 4 with MRI and 30 of 33 with ultrasound. False positive results regarding lymph node metastasis were seen in three patients with hybrid PET, in 14 patients with CT and in 13 patients with ultrasound. MRI yielded no false positive results concerning lymph node metastasis. In one patient, unrecognised metastatic lesions were seen on hybrid PET elsewhere in the body (lung: n=1; bone: n=1). Additional malignant lesions at sites other than the head and neck tumour were found in three patients (one patient with lung cancer, one patient with pelvic metastasis due to a carcinoma of the prostate and one patient with pulmonary metastasis due to breast cancer). It is concluded that [(18)F]FDG PET with hybrid PET scanners is superior to CT and MRI in the diagnosis of primary or recurrent lesions as well as in the assessment of lymph node involvement, whereas it is inferior to ultrasound in the detection of cervical lymph node metastasis.

Adult↗
PubMed2003

[German-speaking memory clinics: state of the art and practical recommendations].

The 7th annual meeting of the memory clinics of Germany, Switzerland and Austria in March 2002 in Göttingen, Germany was an optimal opportunity to make an inventory about the state of the art in diagnostic and therapy of dementia and mild cognitive impairment in German-speaking memory clinics. Several problems were discussed including difficulties in 1) diagnosis of patients with aphasia or foreign patients, 2) handling of demented patients without a caregiver, 3) psychological support for patients, who have been diagnosed in a very early stage, 4) misunderstandings between general practitioners, neurologists and psychiatrists in private practice on the one hand and the memory clinics on the other hand, 5) recommendations for prevention of dementia, 6) recommendations concerning dementia and car driving and 7) questions of genetic counselling. The following paper is a summary of the results of a workshop in Göttingen and gives practical recommendations based on the experiences of the memory clinics.

Aged↗
PubMed2003

[Burden of relatives and their expectations towards psychiatric institutions. A review of the literature and own results].

OBJECTIVE: This article aimed to provide an overview regarding the burden of relatives of mentally ill patients and their expectations towards psychiatric institutions. METHODS: The literature was selected from Medline covering the years 1996 - 2002. 342 articles were reviewed, 145 of which were described in this review. RESULTS: The burden of relatives are manifold and can be classified into the following categories: time spent on caring, financial difficulties, occupational restrictions, detrimental effects on relatives own physical and psychological well-being, reduction in leisure activities, negative effects on social relationships, experiences of discrimination and refusal, deficiencies in information about illness, feelings of not being taken seriously, insufficient service support, long distance to mental health service, emotional burdens of caregivers and difficulties with the patients behaviour. The expectations of the relatives mainly refer to the categories "relationship between staff and relatives", "information about illness" and "establishing of institutions required". CONCLUSION: The various burdens of relatives and their expectations towards psychiatric services point to necessary improvements of mental health services in the sense of a consumer-oriented psychiatric care.

Caregivers↗
PubMed2002

Molecular cloning and characterization of the cathepsin B-like proteinase from the cotton boll worm, Helicoverpa armigera.

An enzyme purified from the ovaries of Helicoverpa armigera, as an active form with molecular mass of 30 kDa on SDS-PAGE, was identified as a cysteine proteinase because it could be inhibited by E-64, a specific inhibitor of cysteine proteinase, and required reducing conditions for activity. This enzyme was further identified as a cathepsin B-like cysteine proteinase by partial amino acid sequencing. A cDNA encoding this proteinase was cloned from H. armigera, using degenerate primers and RACE techniques. Results of Northern blots indicated that the mRNA encoding the proteinase was transcribed in the ovaries, the fat bodies of female and male adults, pupae and in the larvae. No mRNA was detected from the larval epidermis or from the midgut. Hence, transcription of the cathepsin B-like cysteine proteinase from H. armigera was tissue-specific, but not gender- or developmental stage-specific. However, proteolytic activities were only detected from ovaries, and adult female and male fat bodies. No activity was observed from pupal and larval fat bodies, from the larval epidermis or from the midgut. Only one form of mRNA of approximately 1100 bases was detected, and in situ hybridization showed that the transcripts were distributed in the adult female fat bodies, follicular cells and the oocytes. Since the proteinase expressed in ovaries was able to degrade vitellin in vitro, it may be involved in the degradation of vitellin during embryonic development.

Adipose Tissue↗
PubMed2002

A novel mutation of the RP1 gene (Lys778ter) associated with autosomal dominant retinitis pigmentosa.

BACKGROUND: Besides the three known genes (RHO, RDS/Peripherin, NRL) involved in autosomal dominant retinitis pigmentosa (adRP), a fourth gene, RP1, has been recently identified. Initial reports suggest that mutations in the RP1 gene are the second most frequent cause of adRP. The clinical findings were described in a family with adRP and a novel mutation in the RP1 gene. METHOD: Index patients from 15 independent families with adRP in which RHO mutations had been excluded in previous examinations were screened for mutations in the RP1 gene by means of direct DNA sequencing. Evaluation of the RP1 phenotype in patients included funduscopy, kinetic perimetry, dark adapted final threshold test, standard electroretinography and, in one case, multifocal electroretinography. RESULTS: One novel nonsense mutation (Lys778ter) in one of these 15 patients was detected. Cosegregation of the mutation with the disease phenotype could be established in the index patient's family. The phenotype comprises variable expression of clinical disease probably including one case of incomplete penetrance, a onset of symptoms beginning in adulthood, and evidence of regionally varying retinal function loss. CONCLUSION: The Lys778ter mutation localises inside the critical region harbouring all mutations described so far. The ophthalmic findings support previous observations that variation of disease expression appears as a typical feature of the RP1 phenotype.

Aged↗
PubMed2001

Reactivity of a metallacyclopentatriene intermediate: metal-to-ligand-to-metal re-migration of a phosphine ligand versus a 1,2 hydrogen shift.

The reaction of nona-2,7-diyne, deca-2,8-diyne and hex-1-yne with [RuCp(PR3)(MeCN)2]PF6 (R = Cy, Ph, Me) affords, depending on the structure of the alkyne and the substituent of the phosphine ligand, ruthenium metallacyclopentatriene, allyl carbene and/or butadienyl carbene complexes involving either metal-to-ligand-to-metal migration of the phosphine ligand with concomitant C-H activation or a facile 1,2 hydrogen shift.

Journal Article↗
PubMed2001

Purification and properties of two chitinolytic enzymes of Serratia plymuthica HRO-C48.

The chitinolytic rhizobacterium Serratia plymuthica HRO-C48 was previously selected as a biocontrol agent of phytopathogenic fungi. One endochitinase (E.C. 3.2.1.14), CHIT60, and one N-acetyl-beta-1,4- D-hexosaminidase (E.C. 3.2.1.52), CHIT100, were purified and characterized. The endochitinase CHIT60, with an apparent molecular mass of 60.5 kDa, had a N-terminal amino acid sequence highly similar to that of chitinases A from Serratia liquefaciens and Serratia marcescens. The enzyme activity had its peak at 55 degrees C and pH 5.4, and increased by more than 20% in the presence of 10 mM Ca(2+), Co(2+) or Mn(2+). Activity was inhibited by 80% in the presence of 10 mM Cu(2+). CHIT100 appeared to be a monomeric enzyme with a molecular mass of 95.6 kDa and a pI of 6.8. Optimal activity was obtained at 43 degrees C and pH 6.6, and decreased by more than 90 % in the presence of 10 mM Co(2+) or Cu(2+). CHIT100 (100 microg ml(-1)) inhibited spore germination and germ tube elongation of the phytopathogenic fungus Botrytis cinerea by 28 % and 31.6 %, respectively. With CHIT60 (100 microg ml(-1)), the effect was more pronounced: 78 % inhibition of of germination and 63.9 % inhibition of germ tube elongation.

Amino Acid Sequence↗
PubMed2001

Selective extraction of subunit D of the Na(+)-translocating methyltransferase and subunit c of the A(1)A(0) ATPase from the cytoplasmic membrane of methanogenic archaea by chloroform/methanol and characterization of subunit c of Methanothermobacter thermoautotrophicus as a 16-kDa proteolipid.

Chloroform/methanol was applied to cytoplasmic membranes of the thermophilic methanogens Methanothermobacter thermoautotrophicus and Methanothermobacter marburgensis as well as to the mesophile Methanosarcina mazei Gö1. In any case, the chloroform/methanol extraction yielded only two proteins, subunit D (MtrD) of the Na(+)-translocating methyltetrahydromethanopterin:coenzyme M methyltransferase and the proteolipid of the A(1)A(0) ATPase. Both polypeptides are assumed to be directly involved in ion translocation in their respective enzymes, but have not been studied in detail due to lack of simple isolation procedures. The rapid and selective isolation by chloroform/methanol offers a new way to obtain the large quantities of material required for biochemical analyses. As a first result, molecular and biochemical data suggest that the proteolipid from M. thermoautotrophicus is a duplication of the 8-kDa proteolipid usually present in other archaea, but it retained the conserved glutamate involved in proton translocation in every copy. This is the first 16-kDa proteolipid found in archaea.

Adenosine Triphosphatases↗
PubMed2001

A comprehensive two-dimensional map of cytosolic proteins of Bacillus subtilis.

Proteomics relying on two-dimensional (2-D) gel electrophoresis of proteins followed by spot identification with mass spectrometry is an excellent experimental tool for physiological studies opening a new perspective for understanding overall cell physiology. This is the intriguing outcome of a method introduced by Klose and O'Farrell independently 25 years ago. Physiological proteomics requires a 2-D reference map on which most of the main proteins were identified. In this paper, we present such a reference map with more than 300 entries for Bacillus subtilis proteins with an isoelectric point (pI) between 4 and 7. The most abundant proteins of exponentially growing cells were compiled and shown to perform mainly housekeeping functions in glycolysis, tricarboxylic acid cycle (TCC), amino acid biosynthesis and translation as well as protein quality control. Furthermore, putative post-translational modifications were shown at a large scale, with 47 proteins in total forming more than one spot. In a few selected cases evidence for phosphorylation of these proteins is presented. The proteome analysis in the standard pI range was complemented by either stretching the most crowded regions in a narrow pH gradient 4.5-5.5, or by adding other fractions of the total B. subtilis proteome such as alkaline proteins as well as extracellular proteins. A big challenge for future studies is to provide an experimental protocol covering the fraction of intrinsic membrane proteins that almost totally escaped detection by the experimental procedure used in this study.

Bacillus subtilis↗
PubMed2001

Extracellular proteins of Staphylococcus aureus and the role of SarA and sigma B.

Staphylococcus aureus synthesizes a large number of extracellular proteins that have been postulated to play a role in bacterial virulence. The proteomic approach was used to analyse the pattern of extracellular proteins of two different S. aureus strains, RN6390 and COL. Thirty-nine protein spots were identified by N-terminal sequencing or MALDI-TOF-MS. The differences of the extracellular protein patterns between both strains are striking. Among the 18 proteins identified in S. aureus COL there are nine proteins not yet discovered in S. aureus RN6390. These are enterotoxin B, leukotoxin D, enterotoxin, serin proteases (SplA and SplC), thermonuclease, an IgG binding protein and two so far unknown proteins in S. aureus with similarities to SceD precursor in Staphylococcus carnosus and to synergohymenotropic toxin precursor in Streptococcus intermedius. In contrast, lipase as well as staphylokinase identified in S. aureus RN6390 were not detectable in S. aureus COL under the same conditions. By using a regulatory mutant of sarA (ALC136) isogenic to strain RN6390 we identified five proteins positively regulated by SarA and 12 proteins negatively regulated by SarA. Besides V8 protease (StsP) and Hlb already described to be regulated by the sar locus new putatively sarA-dependent proteins were identified, e.g. glycerolester hydrolase and autolysin both down-regulated in the sarA mutant, and aureolysin, staphylokinase, staphopain and format tetrahydrofolate lyase up-regulated in the mutant. Moreover, the role of sigma B in expression of extracellular proteins was studied. Interestingly, we found 11 proteins at an enhanced level in a sigB mutant of S. aureus COL, among them enterotoxin B, alpha and beta hemolysin, serine proteases SplA and SplB, leukotoxin D, and staphopain homologues. The sigma B-dependent repression of gene expression occurs at the transcriptional level. Only one protein, SceD, was identified whose synthesis was down-regulated in the mutant indicating that its gene belongs to the sigma B-dependent general stress regulon.

Amino Acid Sequence↗
PubMed2001

[MRI-assisted brachytherapy of nonresectable liver metastases. Preliminary technical and clinical experiences].

PURPOSE: To evaluate the feasibility and efficacy of MR-guided interstitial brachytherapy of non-resectable liver metastasis. METHODS: Liver metastases (0.8-5.2 cm in diameter) were treated during a prospective phase I/II study using an open 0.2 Tesla MR system (Magnetom Open Viva, Siemens, Erlangen). MR-compatible brachytherapy applicators were placed percutaneously under MR-guidance in an open 0.2 Tesla MR system (Magnetom Open Viva, Siemens, Erlangen) using fast T1-weighted sequences. Pretreatment and follow-up studies were performed using a 1.5 Tesla MR system. RESULTS: Preliminary results of an unpublished prospective study are discussed exemplary on 2 selected patients. The median procedure time was 4.9 h. No major complications were observed and late effects were acceptable. In large symptomatic metastases only a temporary relief of pain was achieved. In smaller metastases (DM 3 cm) a tumor control was observed. CONCLUSION: MR-guided brachytherapy is feasible and has the potential to ablate liver metastases with diameter of less than 3 cm. Further developments are necessary.

Adenocarcinoma↗
PubMed2001

Anticonvulsant action and long-term effects of gabapentin in the immature brain.

The anticonvulsant action and the long-term effects on learning, memory and behavior of the new generation antiepileptic drug gabapentin (GBP) were investigated in immature animals. Kainic acid (KA) was administered to rats on postnatal day (P) 35. Animals were treated with GBP or saline from P36 to P75 and spontaneous seizure frequency was monitored. After tapering the drug, the rats were tested in the water maze and open field test. Brains were then analyzed for histological lesions. Animals treated with GBP following KA-induced status epilepticus had a reduced incidence of spontaneous recurrent seizures, a better pathology score, and less aggressiveness compared to saline-treated controls. Effectiveness of GBP on seizure threshold was tested using flurothyl inhalation in 10 separate age groups of animals ranging from the newborn period to adulthood. Furthermore, GBP plasma concentration peaks were determined in all age groups. At all ages, GBP pre-treated animals demonstrated a higher seizure threshold. Plasma GBP concentrations did not significantly change with age. These data suggest that acute administration of a single therapeutic dose of GBP increases the seizure threshold at all ages studied, while chronic treatment following the status reduces spontaneous seizure frequency and cell damage and has no long-term adverse consequences on cognitive processes during development.

Acetates↗
PubMed2001

Soft tissue concentrations of ciprofloxacin in obese and lean subjects following weight-adjusted dosing.

OBJECTIVE: To investigate whether weight adjusted ciprofloxacin dosing results in comparable target site concentrations in obese and lean subjects. DESIGN: Comparative study in two populations. SUBJECTS: Twelve obese subjects (mean weight 122+/-22.6 kg, 28-52 y, male&ratio;female ratio 4&ratio;8) and 12 age- and sex-matched lean controls (mean weight 59+/-8.6 kg). METHODS: Sampling of interstitial space fluid by means of calibrated in vivo microdialysis after a weight-adjusted intravenous bolus dose of 2.85 mg/kg ciprofloxacin. Analysis of drug concentration by high pressure liquid chromatography. RESULTS: We found significantly higher peak and trough levels of ciprofloxacin in plasma for obese subjects (9.97+/-5.64 and 0.44+/-0.10 microg/ml vs 2.59+/-1.06 and 0.19+/-0.09 microg/ml in lean subjects, P<0.05), while concentration-time curves of interstitial fluid of muscle and subcutaneous fat did not differ between the groups. Tissue penetration, expressed as AUC(tissue)/AUC(plasma) ratio was significantly lower in obese subjects (0.45+/-0.27 vs 0.82+/-0.36, P<0.01). CONCLUSION: We conclude that the penetration process into the interstitial space fluid is impaired in obese subjects. Therefore antibiotic doses need not be adjusted for an increase in fat/water ratio. Weight-adjusted dosing based on actual body weight will yield adequate tissue levels for ciprofloxacin.

Adult↗
PubMed2001

[Automated swinging flashlight test in patients with optic nerve diseases].

AIM OF THE STUDY: The swinging flashlight test is an objective method to diagnose a lesion of the anterior visual pathways. However, errors and faults may easily alter the test's results. Hence, the value of the swinging flashlight test depends highly on the examiner's skills. Therefore an automated and objective procedure was developed which is independent from the examiner. METHODS: A binocularly measuring instrument adapted for video pupillography was supplied with two arrays of light emitting diodes in front of each eye of the subject. By means of this illumination, pupillary light reflexes are elicited alternately. Pupil size is registered continuously, and after artifact elimination, the response amplitudes of the pupils are determined as a mean of right and left pupil. Responses elicited via right and left eye are compared. By varying the stimulus intensity it is possible to measure the amount of the relative afferent pupillary defect. The procedure was tested in 31 patients with optic nerve disorders. RESULTS: The measurements were easily feasible, stable and reliable. Correlation between the relative afferent pupillary defect detected manually by grey filter compensating and with the automated procedure proved to be high. Both variables correlated highly significant with a Spearman rank coefficient of 0.65. If the clinical test is regarded as the golden standard, the automated swinging flashlight test is able to detect 85% of the relative afferent pupillary defects > or = 0.3 logE and 94% of the defects > or = 0.6 logE. CONCLUSION: The automated swinging flashlight test can be recommended to exclude influences by the examiner or if the exact amount of the relative afferent pupillary defect is desired, e.g. when monitoring therapeutic effects in optic nerve diseases. Furthermore, an automated swinging flashlight test could serve as a screening test.

Adult↗
PubMed2001

Single-dose pharmacokinetics of levofloxacin during continuous veno-venous haemofiltration in critically ill patients.

The present study was performed to analyse the pharmacokinetics of levofloxacin during continuous veno-venous haemofiltration (CVVH) with a high-flux polyamide membrane. Twelve patients received 500 mg levofloxacin intravenously. The mean levofloxacin concentration peak was 1.9 +/- 1.0 mg/L. The elimination half-life, haemofiltration clearance and total removal were 8.3 +/- 2.6 h, 27.6 +/- 8.4 mL/min and 56 +/- 19%, respectively. Further multiple-dose studies are required to enable dosage recommendations to be made for patients receiving renal replacement therapy with CVVH.

Anti-Infective Agents↗