Biomedical subjects

C Zimmermann

Publications and source records attributed to C Zimmermann.

At least 19 recordsLinked to original sources

PubMed2007

[Sleep disorders in depression. Suggestions for a therapeutic approach].

Sleep disorder is one of the major symptoms in depression. It can be a risk factor, predictor, or symptom of depressive episodes. Successful therapy of sleep disorder in severely depressed patients can be a problem of its own. So far, there are few data from systematic studies. Definite treatment recommendations and strategies do not exist. The use of sleeping aids is mainly based on clinical experience and arbitrary treatment preferences. This article tries to summarize the difficulties of a rational therapeutic approach to dyssomnia in depressive patients. In addition to medical treatment, the basics of sleep hygiene should be considered. From a pharmacological point of view, sedating antidepressants, short-term add-on benzodiazepines or nonbenzodiazepines, and long-term add-on low potency neuroleptics are considered appropriate treatments. The combination with atypical sedating antipsychotics or low-dose tricyclic antidepressants may be helpful. Drugs which primarily work through serotonin and noradrenalin have negative effects on sleeping disorders since they suppress REM sleep. In contrast to that, GABAergic, antihistaminic, and anticholinergic effects are beneficial for inducing and maintaining sleep. Half-time, pharmacodynamic and pharmacokinetic effects and interactions, and influence of the drugs on reaction time and personal well-being have to be considered.

Antidepressive Agents↗

PubMed2006

Effects of budesonide on P-glycoprotein expression in intestinal cell lines.

BACKGROUND AND PURPOSE: P-glycoprotein (P-gp) is an important efflux transporter that supports the barrier function of the gut against invading antigens and against administered drugs. Since glucocorticoids, such as budesonide, are frequently used during inflammatory bowel disease we investigated how budesonide influences P-gp expression in different intestinal cell lines. EXPERIMENTAL APPROACH: LS180 and Caco-2 cells were incubated with budesonide and changes in P-gp expression were determined on mRNA, protein and functional level. The mRNA expression levels of glucocorticoid receptor (GR) and pregnane X receptor (PXR) were determined in these cell lines. PXR receptor was transiently transfected into Caco-2 cells. KEY RESULTS: Budesonide showed an induction of P-gp in LS180 cells and a down-regulation in Caco-2 cells. Expression levels of nuclear receptors revealed high expression of PXR only in LS180 cells and exclusive expression of GR in Caco-2 cells. Mifepristone, an anti-glucocorticoid, could not reverse the down-regulation of P-gp by budesonide in Caco-2 cells. In PXR-transfected Caco-2 cells the budesonide-mediated down-regulation of P-gp was abolished. Furthermore the expression of cytochrome P450 3A4 (CYP3A4), another PXR target gene, was induced in PXR-transfected Caco-2 cells after budesonide treatment. CONCLUSIONS AND IMPLICATIONS: Budesonide has the potential to influence MDR1 expression in vitro. In LS180 cells, the induction of MDR1 by budesonide probably is mediated via PXR. The mechanism of the down-regulation in Caco-2 cells still remains unclear, but GR does not seem to be involved. Further studies are required to evaluate how budesonide alters P-gp expression in vivo.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2006

Nuclear charge radii of 9,11Li: the influence of halo neutrons.

The nuclear charge radius of 11Li has been determined for the first time by high-precision laser spectroscopy. On-line measurements at TRIUMF-ISAC yielded a 7Li-11Li isotope shift (IS) of 25 101.23(13) MHz for the Doppler-free [FORMULA: SEE TEXT]transition. IS accuracy for all other bound Li isotopes was also improved. Differences from calculated mass-based IS yield values for change in charge radius along the isotope chain. The charge radius decreases monotonically from 6Li to 9Li, and then increases from 2.217(35) to 2.467(37) fm for 11Li. This is compared to various models, and it is found that a combination of halo neutron correlation and intrinsic core excitation best reproduces the experimental results.

Journal Article↗

PubMed2006

[Dosage and kinetics of MMC release of a collagen implant used as a delivery device in glaucoma surgery in the rabbit eye].

PURPOSE: To determine the absorption and the release of mitomycin-C from a collagen implant and tissue impregnation in the anterior structures of the rabbit eye. METHODS: Determining the quantity of mitomycin-C that a collagen implant can absorb with the difference between dry and soaked weight. Mitomycin-C release was measured in vitro using spectrophotometry. The measurement was repeated using a bioassay. Ocular tissue impregnation was determined in 12 eyes of six rabbits. Sclera, implant, aqueous, and ciliary body specimens were collected for concentration measurement using HPLC from 1 to 6 h after surgery. RESULTS: The mean mitomycin-C quantity absorbed in the implant was 3.22+/-0.2 microg. In vitro release was 0.13 mg/ml after 10 min and 0.05 microg/ml at 6 h. The bioassay showed almost no antifibrotic activity in sclera. In vivo release of mitomycin-C was high from the first to the sixth hour. CONCLUSION: After filtering surgery, mitomycin-C in the collagen implant is clearly released and ocular tissues are effectively impregnated.

Animals↗

PubMed2005

Diffraction of a Bose-Einstein condensate from a magnetic lattice on a microchip.

We experimentally study the diffraction of a Bose-Einstein condensate from a magnetic lattice, realized by a set of 372 parallel gold conductors which are microfabricated on a silicon substrate. The conductors generate a periodic potential for the atoms with a lattice constant of 4 microm. After exposing the condensate to the lattice for several milliseconds we observe diffraction up to fifth order by standard time of flight imaging techniques. The experimental data can be quantitatively interpreted with a simple phase imprinting model. The demonstrated diffraction grating offers promising perspectives for the construction of an integrated atom interferometer.

Journal Article↗

PubMed2005

Quantum-degenerate mixture of fermionic lithium and bosonic rubidium gases.

We report on the observation of sympathetic cooling of a cloud of fermionic 6Li atoms which are thermally coupled to evaporatively cooled bosonic 87Rb. Using this technique we obtain a mixture of quantum-degenerate gases, where the Rb cloud is colder than the critical temperature for Bose-Einstein condensation and the Li cloud is colder than the Fermi temperature. From measurements of the thermalization velocity we estimate the interspecies s-wave triplet scattering length |amx|=20(+9)(-6)aB. We found that the presence of residual rubidium atoms in the |2, 1> and the |1, -1> Zeeman substates gives rise to important losses due to inelastic collisions.

Journal Article↗

PubMed2005

Adaptive regulation of the ileal apical sodium dependent bile acid transporter (ASBT) in patients with obstructive cholestasis.

BACKGROUND/AIMS: The apical sodium dependent bile acid transporter ASBT (SLC10A2) contributes substantially to the enterohepatic circulation of bile acids by their reabsorption from the intestine. In the rat, its adaptive regulation was observed in the kidneys, cholangiocytes, and terminal ileum after bile duct ligation. Whether adaptive regulation of the human intestinal ASBT exists during obstructive cholestasis is not known. METHODS: Human ASBT mRNA expression along the intestinal tract was analysed by real time polymerase chain reaction in biopsies of 14 control subjects undergoing both gastroscopy and colonoscopy. Their duodenal ASBT mRNA expression was compared with 20 patients with obstructive cholestasis. Additionally, in four patients with obstructive cholestasis, duodenal ASBT mRNA expression was measured after reconstitution of bile flow. RESULTS: Normalised ASBT expression in control subjects was highest (mean arbitrary units (SEM)) in the terminal ileum (1010 (330)). Low ASBT expression was found in colonic segments (8.3 (5), 4.9 (0.9), 4.8 (1.7), and 1.1 (0.2) in the ascending, transverse, descending, and sigmoid colon, respectively). Duodenal ASBT expression in control subjects (171.8 (20.3)) was found to be approximately fourfold higher compared with patients with obstructive cholestasis (37.9 (6.5); p<0.0001). Individual ASBT mRNA expression was inversely correlated with bile acid and bilirubin plasma concentrations. In four cholestatic patients, average ASBT mRNA increased from 76 (18) before to 113 (18) after relief of cholestasis (NS). Immunohistochemical assessment indicated that ASBT protein was expressed on the apical surface of duodenal epithelial cells. CONCLUSION: Obstructive cholestasis in humans leads to downregulation of ASBT mRNA expression in the distal part of the human duodenum.

Adaptation, Physiological↗

PubMed2005

Phase-sensitive detection of bragg scattering at 1D optical lattices.

We report on the observation of Bragg scattering at 1D atomic lattices. Cold atoms are confined by optical dipole forces at the antinodes of a standing wave generated by the two counterpropagating modes of a laser-driven high-finesse ring cavity. By heterodyning the Bragg-scattered light with a reference beam, we obtain detailed information on phase shifts imparted by the Bragg scattering process. Being deep in the Lamb-Dicke regime, the scattered light is not broadened by the motion of individual atoms.

Journal Article↗

PubMed2005

[Recurrent Candida sepsis with prolonged respiratory failure and severe liver dysfunction].

Systemic mycoses, especially pulmonary diseases and septicemia are observed increasingly at intensive care units. Essential risk factors for development of candidosis are the expanded use of antibiotics and immunocompromised patients, caused either as a result of a severe underlying disease or iatrogenically induced after organ transplantation. Candida albicans is the most frequent pathogen in microbiological findings. Blood cultures are only positive in massive fungemia. We report a 50-year-old patient with recurrent Candida-septicemia: rupture of the distal esophagus after dilatation because of cardiac achalasia with mediastinal emphysema and mediastinitis. Severe acute respiratory distress syndrome after aspiration with septic shock and acute renal failure at the beginning. Long-term mechanical ventilation, continuous renal replacement therapy and multifarious antibiotic therapy. Early microbiological samples of several positive blood cultures and bronchoalveolar lavages revealed the presence of Candida albicans. In the further clinical course, detection of Pseudomonas species in bronchoalveolar lavages and Staphylococci as well as Enterococci in a number of positive blood cultures. Later on development of a severe liver dysfunction with test results that showed an intrahepatic cholestasis. Because of coagulation failure commencement of artificial liver support with the MARS-system (molecule adsorbent recirculating system). Decrease of high bilirubin levels was accompanied by improvement of clinical condition of the patient. In the following course, repeated severe systemic infections with phases of septicemia or rather septic shock and detection of Candida in several positive blood cultures and bronchoalveolar lavages. In each case increasing bilirubin levels with signs of intrahepatic cholestasis and each time improvement with antimycotic therapy (voriconazol, caspofungin and fluconazol). The patient showed more and more signs of immunodeficiency in the sequel. The clinical appearance of candidosis is manifold. Systemic Candida infections are frequent in patients with immunodeficiency. A recurrent Candida septicemia with prolonged respiratory failure and severe liver dysfunction in form of cholestatic hepatosis, that improved several times with antimycotic therapy in combination with evidence based intensive care measures and artificial organ support is a comparatively rare event.

Candida↗

PubMed2004

Nuclear charge radii of 8,9Li determined by laser spectroscopy.

The 2s-->3s transition of (6,7,8,9)Li was studied by high-resolution laser spectroscopy using two-photon Doppler-free excitation and resonance-ionization detection. Hyperfine structure splittings and isotope shifts were determined with precision at the 100 kHz level. Combined with recent theoretical work, the changes in the nuclear-charge radii of (8,9)Li were determined. These are now the lightest short-lived isotopes for which the charge radii have been measured. It is found that the charge radii monotonically decrease with increasing neutron number from 6Li to 9Li.

Journal Article↗

PubMed2004

Self-synchronization and dissipation-induced threshold in collective atomic recoil lasing.

Networks of globally coupled oscillators exhibit phase transitions from incoherent to coherent states. Atoms interacting with the counterpropagating modes of a unidirectionally pumped high-finesse ring cavity form such a globally coupled network. The coupling mechanism is provided by collective atomic recoil lasing, i.e., cooperative Bragg scattering of laser light at an atomic density grating, which is self-induced by the laser light. Under the rule of an additional friction force, the atomic ensemble is expected to undergo a phase transition to a state of synchronized atomic motion. We present the experimental investigation of this phase transition by studying the threshold behavior of this lasing process.

Journal Article↗

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↗