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Biomedical subjects

C Zimmermann

Publications and source records attributed to C Zimmermann.

At least 19 recordsLinked to original sources
PubMed2004

Antioxidant status in acute stroke patients and patients at stroke risk.

BACKGROUND AND PURPOSE: Antioxidant enzymes like copper/zinc superoxide dismutase (SOD), catalase and gluthatione peroxidase (GSHPx) are part of intracellular protection mechanisms to overcome oxidative stress and are known to be activated in vascular diseases and acute stroke. We investigated the differences of antioxidant capacity in acute stroke and stroke risk patients to elucidate whether the differences are a result of chronic low availability in arteriosclerosis and stroke risk or due to changes during acute infarction. METHODS: Antioxidant enzymes were examined in 11 patients within the first hours and days after acute ischemic stroke and compared to risk- and age-matched patients with a history of stroke in the past 12 months (n = 17). Antioxidant profile was determined by measurement of glutathione (GSH), malondialdehyde (MDA), SOD, GSHPx and minerals known to be involved in antioxidant enzyme activation like selenium, iron, copper and zinc. RESULTS: In comparison to stroke risk patients, patients with acute ischemic stroke had significant changes of the GSH system during the first hours and days after the event: GSH was significantly elevated in the first hours (p < 0.01) and GSHPx was elevated 1 day after the acute stroke (p < 0.05). Selenium, a cofactor of GSHPx, was decreased (p < 0.01). GSHPx levels were negatively correlated with National Institutes of Health Stroke Scale (NIHSS) scores on admission (r = -0.84, p < 0.001) and NIHSS scores after 7 days (r = -0.63, p < 0.05). MDA levels showed a trend for elevation in the first 6 h after the acute stroke (p = 0.07). No significant differences of SOD, iron, copper nor zinc levels could be identified. CONCLUSIONS: Differences of antioxidant capacity were found for the GSH system with elevation of GSH and GSHPx after acute stroke, but not for other markers. The findings support the hypothesis that changes of antioxidant capacity are part of acute adaptive mechanisms during acute stroke.

Aged↗
PubMed2004

Decisional strategies for the attribution of emotional distress in primary care.

BACKGROUND: In primary care the General Health Questionnaire (GHQ) is used to provide an independent assessment of probable caseness of psychological disorder against which to test the ability of the general practitioner (GP) to recognize patients with current emotional problems. METHOD: The aim of the present study was to identify those clinical and psychosocial data on patients that increase the likelihood of GPs' attribution of emotional distress (GP model) and those that predict patients' emotional distress as defined by the GHQ-12 (GHQ model). The associations were explored using a classification tree technique (CHAID) and compared using bivariate logistic regression. Six GPs and 444 primary care patients took part. RESULTS: The accuracy indices of the hierarchical GP and GHQ models were 72% and 69% respectively. The availability of information on patients' psychopharmacological and psychiatric/psychological treatment in the last year was the most important predictor of attribution. Occupational, financial and housing problems and life events of loss were the most important predictors of the GHQ-12 case definition. The overall accuracy of the bivariate model was 73%. Compared with the GHQ-12, GPs gave significantly more importance to psychiatric treatment, psychopharmacological drug use and chronic illness. CONCLUSIONS: The findings suggest that to improve the detection of current emotional distress in primary care patients GPs should pay foremost and systematic attention to social problems and recent life events of loss. These problems are important clues for the possible presence of emotional distress, whereas critical patient data, in particular psychiatric history and psychopharmacological treatment, increase the probability of attribution errors.

Affective Symptoms↗
PubMed2003

Observation of lasing mediated by collective atomic recoil.

We observe the buildup of a frequency-shifted reverse light field in a unidirectionally pumped high-Q optical ring cavity serving as a dipole trap for cold atoms. This effect is enhanced and a steady state is reached, if via an optical molasses an additional friction force is applied to the atoms. We observe the displacement of the atoms accelerated by momentum transfer in the backscattering process and interpret our observations in terms of the collective atomic recoil laser. Numerical simulations are in good agreement with the experimental results.

Journal Article↗
PubMed2003

[Intrapericardial fibrinolysis as a therapeutic option in a case of purulent pericarditis].

HISTORY AND ADMISSION FINDINGS: A 23-year-old man known to have Hodgkin's disease in remission and C-protein deficiency presented with chest pain and symptoms of respiratory infection. INVESTIGATIONS: A purulent pericardial effusion was detected by echocardiography. The chest X-ray showed a left-sided pneumonia. TREATMENT AND CLINICAL COURSE: When pericardiocentesis failed to drain the purulent but pathogen-free effusion completely, streptokinase was several times instilled intrapericardially and achieved fibrinolysis without complication. The effusion did not recur. CONCLUSIONS: Intrapericardial application of fibrinolytic agents seems to be an effective treatment of a purulent pericarditis.

Adult↗
PubMed2003

Nonlinear dynamics of a Bose-Einstein condensate in a magnetic waveguide.

We have studied the internal and external dynamics of a Bose-Einstein condensate in an anharmonic magnetic waveguide. An oscillating condensate experiences a strong coupling between the center of mass motion and the internal collective modes. Because of the anharmonicity of the magnetic potential, not only the center of mass motion shows harmonic frequency generation, but also the internal dynamics exhibit nonlinear frequency mixing. Thereby, the condensate shows shape oscillations with an extremely large change in the aspect ratio of up to a factor of 10. We describe the data with a theoretical model to high accuracy. For strong excitations we test the experimental data for indications of a chaotic behavior.

Journal Article↗
PubMed2003

L-arginine improves diminished cerebral CO2 reactivity in patients.

BACKGROUND AND PURPOSE: There is experimental evidence that L-arginine restores diminished CO2 reactivity after mild traumatic brain injury in rats. This effect is believed to be mediated by L-arginine-derived nitric oxide, which is a permissive substrate for CO2 reactivity. To clarify whether these findings can be transferred to the clinical situation and have beneficial effects in patients, we studied the effects of L-arginine on CO2 reactivity of the cerebral vessels in patients with impaired vasomotor reactivity (VMR) and compared them with patients with normal VMR. METHODS: Twenty-two patients with cardiovascular risk factors and VMR <50% with no extracranial or intracranial stenoses were examined by bilateral transcranial Doppler sonography of the right and left middle cerebral arteries and compared with 20 age- and risk-matched patients with normal VMR (>50%). VMR was tested by L-minute hyperventilation, followed by a 3-minute inhalation of 5% CO2. Examinations were performed before and after infusion of 30 g L-arginine over 30 minutes. The 22 patients with reduced VMR (<50%) were compared with 20 patients with normal VMR (>50%). RESULTS: Initial mean VMR of the 42 patients was 50+/-12%. There was no difference between the right- and the left-side VMR. In the 22 patients with reduced VMR in the first examination (42+/-8%), VMR increased significantly after infusion of L-arginine (52+/-14%, P=0.005). In contrast, values did not change after infusion of L-arginine in the 20 patients with normal VMR (59+/-8% before versus 59+/-13% after L-arginine). There was a negative correlation of initial CO2 vasoreactivity and the percentage of VMR increase after infusion of L-arginine. CONCLUSIONS: Our data support the hypothesis that in humans L-arginine is able to improve impaired CO2 reactivity of the cerebral vessels. This effect can be found in patients at cardiovascular risk with impaired VMR and might have therapeutic implications in the future.

Aged↗
PubMed2003

[Reninoma: a rare but curable cause of high blood pressure, a case report].

We report a case of a renin secreting tumor, which is a very rare cause of secondary high blood pressure. A 22-year-old woman was hospitalised for exploration of high blood pressure (160/110 mmHg) with severe hypokaliemia (2,7 mmol/l) and secondary hyperaldosteronism. Physical examination was normal except the high blood pressure. Bioassays show increased kaliuresis (66 mmol/24h), plasma renin (89 pg/ml in clinostastism--108 pg/ml in orthostatism), pro-renin (1207 pg/ml in clinostastism--1412 pg/ml in orthostatism) and aldosterone (210 pg/ml in clinostastism--566 pg/ml in orthostatism). The rest of the endocrine tests were normal (cortisol and ACTH at 8:00 am, urinary free cortisol, overnight 1 mg dexamethasone suppression test). Doppler ultrasound method, performed by an experienced radiologist, did not show renal artery stenosis. Abdominal computerized tomography showed a nodular formation at the upper pole of the right kidney, isodense to renal medullary. The size tumor was 15 mm. The renal vein sampling shows high values of renin on both sides whereas, for the pro-renin, the values were higher on the tumor side. In spite of treatment with CEI (Converting Enzyme Inhibitors) and calcium antagonists, the blood pressure was not controlled. Hypokaliemia persisted (3 mmol/l) in spite of high daily potassium intake (64 mmol/l of potassium chloride). After tumor resection, reninoma was diagnosed by the pathology examination and blood pressure, plasma rennin, plasma aldosterone level returned to normal.

Adult↗
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↗