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Biomedical subjects

C Zimmermann

Publications and source records attributed to C Zimmermann.

At least 37 records · Page 2Linked to original sources
PubMed2002

[Undetected tracheal tumours responsible for ventilator-dependency].

HISTORY AND CLINICAL FINDINGS: Case 1 A patient with former carcinoma of the larynx became dependent on mechanical ventilation. She failed to be weaned from the respirator because of severe bronchial obstruction, therefore she was transferred to a weaning center. Case 2 A COPD patient with respirator dependency due to infectious exacerbation underwent percutaneous tracheostomy shortly after primary intubation. Status asthmaticus was considered to be the reason of following unsuccessful weaning. INVESTIGATIONS, DIAGNOSIS AND TREATMENT: Case 1 Performing a bronchoscopy the diagnosis of a central tumor (local recurrence) was found causing nearly total obstruction of the trachea. The ensuing treatment was restricted to palliation. Case 2 After transferral to the weaning center a small cell lung cancer located in the central tracheal was identified by bronchoscopy. The tumor masses were exstirpated by laser technique and the patient was weaned immediately afterwards. Chemotherapy and radiation of the mediastinum were performed. CONCLUSIONS: Fibreoptic bronchoscopy is an essential tool concerning diagnosis and treatment of tracheal tumors which may cause difficult weaning from mechanical ventilation. Every percutaneous tracheostomy should be performed with endoscopical guidance.

Adult↗
PubMed2002

The autoimmune response to chromatin antigens in systemic lupus erythematosus: autoantibodies against histone H1 are a highly specific marker for SLE associated with increased disease activity.

This study investigates specificity, sensitivity and concomitant presence of antibodies against histone H1 (H1), nucleosomes (NUC), chromatin (CHR) and dsDNA in patients with systemic lupus erythematosus (SLE), analyses their association with SLE disease activity and characterizes the immunodominant epitope reactivity of anti-H1 antibodies and its relation to SLE disease activity. In a cross-sectional study 394 sera of patients with various rheumatic diseases and healthy subjects were analysed by ELISA for antibodies against H1, NUC, CHR and dsDNA. In addition, a longitudinal analysis was performed that included 121 sequential serum samples derived from 16 SLE patients to assess the relation of these antibodies as well as antibodies to histone H2B to SLE disease activity. To assess epitope reactivity of anti-H1 antibodies overlapping synthetic peptides covering the entire H1 sequence were used. Anti-H1 antibodies yielded a sensitivity of approximately 45% and a specificity of over 98% for SLE, which was comparable to that found for anti-dsDNA antibodies. Anti-CHR and anti-NUC antibodies were of similar sensitivity but slightly (anti-CHR) or considerably (anti-NUC) less specific for SLE (95 and 85%, respectively). The sequential analysis revealed a strong correlation of anti-H1 antibodies with SLE disease activity that was better than the correlation of anti-dsDNA and anti-NUC antibodies, while only weak correlation was found for anti-CHR and anti-H2B antibodies. The immunodominant epitope for anti-HI was localised between amino acids 204 and 218 (pp204-218) and immune reactivity to this epitope also correlated with disease activity. Anti-H1 is a highly specific marker for SLE with a diagnostic value comparable to anti-dsDNA. A positive testing for anti-H1 indicates increased disease activity, as does the appearance of antibodies to its immunodominant epitope pp204-218.

Antibodies, Antinuclear↗
PubMed2001

Action and distribution of organic solvent contaminations in hydrating cement: time-resolved insights into solidification of organic waste.

Cementitious materials are widely used as binders both in construction and in environmental technology (e.g., for stabilization and solidification). When dealing with materials contaminated with organic solvents, it is important to have an idea about the interaction between the solvents and the hydrating cement. Here, we introduce nuclear magnetic resonance relaxometry experiments as a way to study both the influence of organic model contaminants on the hydration kinetics of cement and the distribution of the contaminant in the cement matrix during the first hours and days of hydration. All solvents were found to lead to some delay in the hydration kinetics. While nonpolar compounds only lead to a minor delay and qualitatively to the same hydrating kinetics as in an uncontaminated cement mixture, the polar solvents lead to much more pronounced delays in the hydration kinetics. For toluene contents in the low percent range, there was no indication for the formation of macroscopic liquid pockets in the hydrating cement paste. The findings are consistent with recent results on the distribution of toluene in fully hydrated concrete samples.

Cementation↗
PubMed2001

Bose-Einstein condensation in a surface microtrap.

Bose-Einstein condensation has been achieved in a magnetic surface microtrap with 4 x 10(5) (87)Rb atoms. The strongly anisotropic trapping potential is generated by a microstructure which consists of microfabricated linear copper conductor of widths ranging from 3 to 30 microm. After loading a high number of atoms from a pulsed thermal source directly into a magneto-optical trap the magnetically stored atoms are transferred into the microtrap by adiabatic transformation of the trapping potential. In the microtrap the atoms are cooled to condensation using forced rf-evaporation. The complete in vacuo trap design is compatible with ultrahigh vacuum below 2 x 10(-11) mbar.

Journal Article↗
PubMed2001

Lipopolysaccharide-induced ischemic tolerance is associated with increased levels of ceramide in brain and in plasma.

Intravenous administration of lipopolysaccharide (LPS) (0.9 mg/kg) has been shown to induce ischemic tolerance in spontaneously hypertensive rats (SHR). TNF-alpha is believed to play a crucial role in preconditioning as its inhibition with TNF-alpha-binding protein abolished tolerance. Our recent studies (Liu et al., Am. J. Physiol. 278 C144, 2000) have demonstrated that ceramide, a downstream messenger in TNF-alpha signaling, is a mediator of hypoxia-induced tolerance in neuronal cells. To test the hypothesis that ceramide contributes to LPS-induced tolerance in vivo, SHR were injected intravenously with either LPS or saline and the levels of ceramide in brain and in plasma were determined by reversed phase HPLC. LPS injection resulted in a significant increase of ceramide in plasma with a maximum at 24 h (8.32+/-1.14 pmol/microl (LPS) vs. 2.65+/-0.62 pmol/microl (saline)). LPS also induced ceramide upregulation in brain cortex, which started between 6 and 12 h and remained elevated up to 48 h after LPS injection. Fluorescent NBD-C6 ceramide was able to cross blood-brain barrier and was found in brain vessels, perivascular cells and in brain parenchyma 30 min after intravenous injection. These findings demonstrate that LPS preconditioning leads to elevation of ceramide in brain and plasma and, in conjunction with previous work, suggests that ceramide plays a role in LPS-induced protection against brain ischemic injury in vivo.

4-Chloro-7-nitrobenzofurazan↗
PubMed2001

Further results on the reliability of the Parental Bonding Instrument (PBI) in an Italian sample of schizophrenic patients and their parents.

The reliability of the Italian version of the Parental Bonding Instrument (PBI) was assessed in a group of 26 schizophrenic patients and their parents. In both groups, internal consistency indices were satisfactory and mean PBI scores at test and retest were stable. The test-retest reliability coefficients for the PBI scales of parents ranged from .65 to .67, those of the patients from .32 (paternal-protection score) to .67 (maternal-care score). The less satisfactory test-retest reliability of patients' paternal protection score was due to minor intra-category rather than inter-category variations in their ratings. This suggests difficulties with a four-point rating scale, which might depend partly on the generally poor schooling of the sample, but it may also reflect uncertainty of schizophrenic patients concerning fathers' controlling behavior. Further studies should pay attention to this factor. Patients' PBI mean scores are compatible with an affection-less control rearing style, while those of their parents, characterized by similar poor care but less control, are consistent with a pattern of weak parental bonding.

Adolescent↗
PubMed2001

Use of dobutamine stress echocardiography in detecting silent myocardial ischaemia in asymptomatic diabetic patients: a comparison with thallium scintigraphy and exercise testing.

AIMS: Silent myocardial ischaemia is frequent in diabetic patients. The aim of this study was to compare the efficacy of thallium-201 single-photon emission computed tomography (201Tl SPECT) coupled with exercise stress testing (EST), and dobutamine stress echocardiography (DSE) in the detection of asymptomatic coronary artery disease. METHODS: Fifty-six asymptomatic diabetic patients, with a known duration of diabetes > 15 years for Type 1 and > 5 years for Type 2, having at least three added risk factors, but without rest ECG abnormalities, were enrolled in this prospective study. All of them were submitted to DSE with a maximum infusion rate of 40 microg/kg per min dobutamine +/- i.v. atropine, and to 201Tl SPECT coupled with EST. Coronary angiography was performed if at least one test was abnormal. RESULTS: Diabetic patients were 37 males and 19 females, aged mean (sd) 60 +/- 10 years, 10 Type 1 and 46 Type 2, with a known duration of disease of mean (sd) 17 +/- 9 years. Feasibility of DSE was 91%. No serious complication occurred during the test. Coronary angiography was performed in 26 patients (47%); 17 were abnormal (30% of the whole group): six patients had a one-vessel, six a two-vessel and five a three-vessel disease. Predictive positive value was 69% for DSE, 75% for 201Tl SPECT and 60% for EST. DSE was falsely negative in four cases vs. eight for 201Tl SPECT and nine for EST. CONCLUSIONS: Asymptomatic coronary disease is common in diabetes associated with other risk factors. DSE appears useful in its detection and a good alternative to 201Tl SPECT.

Adult↗
PubMed2000

A new route into single-crystalline partially oxidized cobalt compounds: reactions with zintl-type hexaselenodistannate(III) K6Sn2Se6 as mild oxidant

Reactions of K6Sn2Se6 (1) with [Cp*CoCl]2 were investigated in order to probe the stability of the formal +3 oxidation state at Sn and possible ligand properties of heteroatomic zintl-type anion "Sn2Se6(6)- ". From these experiments, we obtained the following compounds that are oxidized to different extent as a result of the reaction with SnIII: [Cp2*Co][Cl2Co(mu2-Cl)2Li(thf)2] (2), [(Cp*Co)3(mu-Se)2] (3), [(Cp*Co)3(mu3-Se)2][Cl2Co(mu2-Cl)2Li(thf)2] (4), and [(Cp*Co)4(mu3-Se)4] (5). These compounds were structurally characterized by single-crystal X-ray diffractometry. It shows that the reaction conditions strongly affect the type and oxidation state of the isolated product. Two of the observed compounds, 3 and 4, are closely related both structurally and electronically; this is discussed and further illustrated by cyclovoltammetric measurements. The choice of the terminal Cp* ligand attached to the transition metal in the reactand complex is assumed to be basically dependent for the alignment of unexpected structural details when compared with known compounds of similar compositions. In conclusion, 1 is observed to act as mild oxidant as well as selenide donor, but is not in the position to keep its Sn-Se framework under the given reaction conditions.

Journal Article↗
PubMed2000

Differences in verbal behaviours of patients with and without emotional distress during primary care consultations.

BACKGROUND: In primary care consultations patients with emotional distress tend to give verbal cues or symptom reports with psychological or psychiatric contents. This study examined the cue behaviour defined not only by psychological, but also by medical, social and life episodes related contents in patients with and without emotional distress, recognized and not by their GP. The GP's verbal behaviour in relation to patients' cue emission was also investigated. METHOD: For the six participating GPs two groups of matched pairs of patients (N = 238) were created. The two groups comprised either patients considered by GPs as being without emotional distress or patients considered as emotionally distressed. Within each pair, one patient was a case (GHQ-12 score > 2) and the other was the matched control (GHQ-12 score < 3). The medical interviews with these patients were transcribed and classified according to the Verona Medical Interview Classification System (VR-MICS). RESULTS: GHQ positive patients of both groups gave more cues in terms of total proportion than their matched controls (GHQ negative patients). The proportion of cues given by patients was related also to GP's verbal behaviour, increasing with closed psychosocial questions and decreasing with the use of active interview techniques. Attribution of emotional distress was more frequent when patients were high attenders and had a past psychiatric history. The content of cues changed in relation to GP's attribution: recognized patients gave more cues and more often with psychological content, patients not recognized as distressed gave mainly cues related to their lifestyle and life episodes. CONCLUSIONS: To improve the recognition of those emotionally distressed patients most likely to be missed GPs should increase their attention to cues related to life style and life episodes.

Adult↗
PubMed2000

Framing of outcome and probability of recurrence: breast cancer patients' choice of adjuvant chemotherapy (ACT) in hypothetical patient scenarios.

PURPOSE: To examine the effects of framing of outcome and probabilities of cancer occurrence on the treatment preference which breast cancer patients indicate for hypothetical patient scenarios. METHODS: A modified version of the Decision Board Instrument (Levine et al. 1992) was administered to 35 breast cancer patients with past ACT experience. Patients expressed their choice regarding ACT for six scenarios which were characterized by either negative or positive framing of outcome and by one of the three levels of probability of recurrence (high, medium, low). RESULTS: The framing had no influence on ACT choices over all three probability levels. The majority chose ACT for high and medium risk and one third switched from ACT to No ACT in the low-risk condition. This switch was statistically significant. CONCLUSION: Hypothetical treatment decisions against ACT occur only when the probability of recurrence is low and the benefit of ACT is small. This finding for patients with past experience of ACT is similar to those reported for other oncological patient groups still in treatment.

Adult↗
PubMed2000

Analysis of the molecular composition of Ro ribonucleoprotein complexes. Identification of novel Y RNA-binding proteins.

Human Ro ribonucleoproteins (RNPs) are composed of one of the four small Y RNAs and at least two proteins, Ro60 and La; association of additional proteins including the Ro52 protein and calreticulin has been suggested, but clear-cut evidence is still lacking. Partial purification of Ro RNPs from HeLa S100 extracts allowed characterization of several subpopulations of Ro RNPs with estimated molecular masses of between 150 and 550 kDa. The majority of these complexes contained Ro60 and La, whereas only a small proportion of Ro52 appeared to be associated with Ro RNPs. To identify novel Y RNA-associated proteins in vitro, binding of cytoplasmic proteins to biotinylated Y RNAs was investigated. In these reconstitution experiments, several proteins with estimated molecular masses of 80, 68, 65, 62, 60 and 53 kDa, the latter two being immunologically distinct from Ro60 and Ro52, respectively, appeared to bind specifically to Y RNAs. Furthermore, autoantibodies to these proteins were found in sera from patients with systemic lupus erythematosus. The proteins bound preferentially to Y1 and Y3 RNA but, with the exception of the 53-kDa protein, only weakly to Y4 RNA and not at all to Y5 RNA. Coprecipitation of the 80, 68, 65, and 53-kDa proteins by antibodies to Ro60 and La was observed, suggesting that at least a proportion of the novel proteins may reside on the same particles as La and/or Ro60. Finally, the binding sites for these proteins on Y1 RNA were clearly distinct from the Ro60-binding site involving a portion of the large central loop 2, which was found to be indispensable for binding of the 80, 68, 65 and 53-kDa proteins, as well as the stem 3-loop 3 and stem 2-loop 1 regions. Interestingly, truncation of the La-binding site resulted in decreased binding of the novel proteins (but not of Ro60), indicating La to be required for efficient association. Taken together, these results suggest the existence of further subpopulations of Ro RNPs or Y RNPs, consistent with the heterogeneous characteristics observed for these particles in the biochemical fractionation experiments.

Autoantibodies↗
PubMed2000

[Value of retrospective assessment of the Epworth Sleepiness Scale after long-term CPAP therapy in obstructive sleep apnea disorder]].

BACKGROUND: Daytime-sleepiness is the main symptom of the obstructive sleep apnoea syndrome. Standarized questionnaires (e.g. the Epworth sleepiness scale = ESS) have become useful diagnostic tools. In this study we investigated wether there is a difference between the estimation of initial "pre-treatment" daytime sleepiness (by ESS) compared to the retrospective ESS score after implementation of CPAP therapy. PATIENTS AND METHODS: We included 46 patients (RDI 39/h +/- 20.2, CPAP pressure 8 cm/H2O +/- 1.7, daily use of 5.8 h +/- 1.8, RDI with CPAP 7.6/h +/- 5.3). We examined the ESS score before CPAP-therapy (ESS-base) in comparison to the retrospective estimation of the initial conditions after one year of CPAP-therapy (ESS-retro). RESULTS: There was no statistical significant difference between ESS base (11.7 +/- 4.6) and ESS-retro (12.7 +/- 5.2). ESS decreased to 5.4 +/- 3.7 by CPAP-therapy (p < 0.01). CONCLUSION: From a chronological point of view ESS is a consistent parameter of daytime sleepiness. Hence, the retrospective estimation of pre-CPAP ESS can be considered as a useful diagnostic tool.

Adult↗
PubMed2000

Plasminogen activation in focal cerebral ischemia and reperfusion.

In focal cerebral ischemia the plasminogen-plasmin system plays a role in the fibrinolysis of vessel-occluding clots and also in the proteolysis of extracellular matrix components, which potentially contributes to brain edema and bleeding complications. The authors investigated the plasminogen activation after middle cerebral artery occlusion with and without reperfusion (reperfusion intervals 9 and 24 hours) in rats by histologic zymography and compared areas of increased plasminogen activation to areas of structural injury, which were detected immunohistochemically. After 3 hours of ischemia, increased plasminogen activation was observed in the ischemic hemisphere. The affected area measured 5.2%+/-8.5% and 19.4%+/-30.1% of the total basal ganglia and cortex area, respectively. Reperfusion for 9 hours after 3 hours of ischemia led to a significant expansion of plasminogen activation in the basal ganglia (68.8%+/-42.2%, P < 0.05) but not in the cortex (43.0%+/-34.6%, P = 0.394). In the basal ganglia, areas of increased plasminogen activation were related to areas of structural injury (r = 0.873, P < 0.001). No such correlation was found in the cortex (r = 0.299, P = 0.228). In this study, increased plasminogen activation was demonstrated early in focal cerebral ischemia. This activation may promote early secondary edema formation and also secondary hemorrhage after ischemic stroke.

Animals↗
PubMed1999

T cell ignorance in mice to Borna disease virus can be overcome by peripheral expression of the viral nucleoprotein.

Infection of neonates with Borna disease virus (BDV) induces severe meningoencephalitis and neurological disorder in wild-type but not in beta(2)-microglobulin-deficient mice of strain MRL (H-2(k)). Temporary in vivo depletion of CD8(+) T cells delayed BDV-induced disease for several weeks. Depletion of CD4(+) T cells had a similar beneficial effect, indicating that the BDV-induced neurological disorder in mice is a CD4(+) T cell-dependent immunopathological process that is mediated by CD8(+) T cells. Lymphocytes prepared from brains of diseased mice were mainly from the CD8(+) T cell subset. They showed up-regulation of activation markers and exerted strong MHC I-restricted cytotoxic activity against target cells expressing the BDV nucleoprotein p40. Infection of B10.BR (H-2(k)) or congenic C57BL/10 (H-2(b)) mice resulted in symptomless, lifelong persistence of BDV in the brain. Superinfection with a recombinant vaccinia virus expressing BDV p40 but not with other vaccinia viruses induced severe neurological disease and encephalitis in persistently infected B10.BR mice but not in persistently infected C57BL/10 mice, indicating that the disease-inducing T cell response is restricted to the nucleoprotein of BDV in H-2(k) mice. Our results demonstrate that the cellular arm of the immune system may ignore the presence of a replicating virus in the central nervous system until proper antigenic stimulation at a peripheral site triggers the antiviral response.

Animals↗
PubMed1999

A novel approach to visualize polyclonal virus-specific CD8 T cells in vivo.

Recent technical breakthroughs in generating soluble MHC class I-peptide tetramers now allow the direct visualization of virus-specific CD8 T cells after infection in vivo. However, this technique requires the knowledge of the immunodominant viral epitopes recognized by T cells. Here, we describe an alternative approach to visualize polyclonal virus-specific CD8 T cells in vivo using a simple adoptive transfer system. In our approach, C57BL/6 (Thy1.2) mice were infected with lymphocytic choriomeningitis virus, vesicular stomatitis virus, or vaccinia virus to induce virus-specific memory T cells. Tracer T cells (2 x 106) from these virus-immune mice were adoptively transferred into nonirradiated (C57BL/6 x B6.PL-Thy-1a)F1 mice. After infection of the F1-recipient mice with the appropriate virus, the transferred cells expanded vigorously, and on day 8 postinfection 60-80% of total CD8 T cells were of donor T cell origin. Under the same conditions memory CD4 T cells gave rise to at least 10 times less cell numbers than memory CD8 T cells. The transfer system described here not only allows to visualize effector and memory CD8 T cells in vivo but also to isolate them for further in vitro characterization without knowing the epitopes recognized by these Ag-specific CD8 T cells.

Adoptive Transfer↗
PubMed1999

Protection against lymphocytic choriomeningitis virus infection induced by a reduced peptide bond analogue of the H-2Db-restricted CD8(+) T cell epitope GP33.

Recent investigations have suggested that pseudopeptides containing modified peptide bonds might advantageously replace natural peptides in therapeutic strategies. We have generated eight reduced peptide bond Psi(CH2-NH) analogues corresponding to the H-2Db-restricted CD8(+) T cell epitope (called GP33) of the glycoprotein of the lymphocytic choriomeningitis virus. One of these pseudopeptides, containing a reduced peptide bond between residues 6 and 7 (Psi(6-7)), displayed very similar properties of binding to major histocompatibility complex (MHC) and recognition by T cell receptor transgenic T cells specific for GP33 when compared with the parent peptide. We assessed in vitro and in vivo the proteolytic resistance of GP33 and Psi(6-7) and analyzed its contribution to the priming properties of these peptides. The Psi(6-7) analogue exhibited a dramatically increased proteolytic resistance when compared with GP33, and we show for the first time that MHC-peptide complexes formed in vivo with a pseudopeptide display a sustained half-life compared with the complexes formed with the natural peptide. Furthermore, in contrast to immunizations with GP33, three injections of Psi(6-7) in saline induced significant antiviral protection in mice. The enhanced ability of Psi(6-7) to induce antiviral protection may result from the higher stability of the analogue and/or of the MHC-analogue complexes.

Amino Acid Sequence↗