PubMed Health⌕ Search

Biomedical subjects

A Gerber

Publications and source records attributed to A Gerber.

At least 37 records · Page 2Linked to original sources
PubMed2001

Sudden cardiac death after coronary artery bypass grafting is not predicted by signal-averaged ECG.

BACKGROUND: Sudden cardiac death (SCD) is a major cause of death despite successful revascularization in patients with coronary artery disease. The signal-averaged ECG (SAECG) is a sensitive predictor of SCD and could be used in the screening strategy to select patients for prophylactic cardioverter implantation. METHODS: The SAECG was recorded in 561 patients (mean age: 60 +/- 8.8 years) within 10 days of coronary artery bypass grafting. Signal-averaged ECG was performed with a bandpass filtering of 40 to 250 Hz for more than 250 beats until a noise level of 0.6 microV was achieved. All patients were followed for 5.5 +/- 1.2 years after the procedure. RESULTS: Preoperative angiographic ejection fraction was at least 60% in 393 patients (72%), 40% to 60% in 126 patients (23%), and 40% or less in 28 patients (5%). There were 34 deaths, 10 of which were SCD. Late potentials were found in a total of 150 patients (27%) and were equally frequent preoperatively and postoperatively and among patients with (30%) and without (27%) SCD. The only predictors for overall mortality were age and a reduced ejection fraction. CONCLUSIONS: Signal-averaged ECG did not predict prognosis in low-risk patients undergoing coronary artery bypass grafting.

Coronary Artery Bypass↗
PubMed2001

Instability of shoulder arthroplasty: balancing mobility and stability.

Avoidance of instability after shoulder arthroplasty is based on an appreciation of normal articular anatomy and its restoration, as well as adequate soft tissue release and secure repair of subscapularis. Errors in restoration of articular anatomy, or disruption of soft tissues about the joint, are the principal reasons for instability. Revision in such cases can be challenging because of difficulties in restoring normal articular position and orientation, as well as reconstruction of deficient soft tissues.

Arthroplasty, Replacement↗
PubMed2001

Ketamine for short ambulatory procedures in children: an audit.

BACKGROUND: The purpose of this audit was the evaluation of recovery and discharge times and the identification of perioperative events related to anaesthetics with intravenous ketamine and midazolam. METHODS: In our institution, we use this method as a routine technique for short ambulatory emergency or elective procedures. Two hundred children, aged 1-16 years, were included. Ninety percent of the study patients underwent emergency procedures. RESULTS: Most perioperative events were minor and easily corrected. Intraoperatively, most events were related to respiration, including oxygen desaturation, apnoea or laryngospasm. Vomiting, vertigo, visual disturbances, nightmares and hallucinations were observed in the postoperative period. Serious complications requiring hospital admission or further interventions in the postoperative period were rare. Mean recovery time was 100 min (range 20-325) and mean discharge time 130 min (range 25-360). CONCLUSIONS: Intravenous ketamine plus midazolam is a suitable, simple and fast anaesthetic technique for short, painful ambulatory procedures. Considering the possibility of potentially serious respiratory complications, it should be performed only by qualified anaesthesia staff who are trained in advanced airway management.

Adolescent↗
PubMed2001

Anatomy and intracompartmental pressure measurement technique of the pronator quadratus compartment.

The compartment of the pronator quadratus muscle in 25 cadaver specimens is described. Defined by the radius, ulna, and distal interosseous membrane dorsally and the pronator quadratus fascia on the palmar side, the osteofibrous walls of the compartment confine the pronator quadratus muscle within a noncompliant space. A safe and reliable location for compartment pressure measurement was defined at a site 4 cm proximal to the scaphoid tubercule, on the radial side of the flexor carpi radialis tendon and on the ulnar side of the radial artery. These clear anatomic definitions might be useful in diagnosis of compartment syndrome of the pronator quadratus; a clinical investigation may be justified on the basis of pressure measurements made using this technique.

Cadaver↗
PubMed2001

Interleukin-6 and transforming growth factor-beta 1 control expression of cathepsins B and L in human lung epithelial cells.

Cathepsins B and L are commonly expressed cysteine proteinases that play a major role in lysosomal bulk proteolysis, protein processing, matrix degradation, and tissue remodeling. Cathepsins are also implicated in tumor progression and metastasis, tissue injury, and inflammation. Cells at sites of inflammation often show upregulation and secretion of cathepsins. The regulation of cathepsin expression by inflammatory mediators is not well understood. The aims of this study were to investigate the effect of the cytokines interleukin-1 beta (IL-1 beta), IL-6, IL-10, transforming growth factor-beta 1 (TGF-beta 1), and hepatocyte growth factor (HGF) on expression of cathepsin B and cathepsin L mRNA (quantitative RT-PCR), on protein expression (ELISA, Western blot), and also on enzymatic activity of cathepsins B and L. Investigations were performed using the human lung epithelial cell line A-549. IL-6 was found to induce a concentration-dependent increase in mRNA expression, protein concentration, and enzymatic activity of cathepsin L. Cathepsin B mRNA and protein expression were not affected by IL-6. In contrast, TGF-beta 1 decreased the amount of cathepsin L mRNA and cathepsin B mRNA. At protein level, it was shown that TGF-beta 1 clearly reduced the concentration of cathepsin L but not cathepsin B. The cytokines IL-1 beta, IL-10, and HGF were found to exert no effect on cathepsin B and L expression. In conclusion, these results are the first to show that IL-6 and TGF-beta 1 have opposite effects on the regulation of expression of cathepsins B and L in A-549 human lung epithelial cells. The proinflammatory cytokine IL-6 induced an upregulation of cathepsin L, whereas TGF-beta 1 suppressed cathepsin B and L expression. Further studies are needed to clarify the mechanism that affects cathepsin B and L expression.

Cathepsin B↗
PubMed2001

The effects of sevoflurane and halothane anesthesia on cerebral blood flow velocity in children.

UNLABELLED: We compared cerebral blood flow velocity during anesthesia with sevoflurane and halothane in 23 children admitted for elective surgery (age, 0.4-9.7 yr; median age, 1.9 yr; ASA physical status I-II). Inhaled induction was performed in a randomized sequence with sevoflurane or halothane. Under steady-state conditions, cerebral blood flow velocity (systolic [V(s)], mean [V(mn)], and diastolic [VD]) were measured by a blinded investigator using transcranial pulsed Doppler ultrasonography. The anesthetic was then changed. CBFV measurements were repeated after washout of the first anesthetic and after steady-state of the second (equivalent minimal alveolar concentration to first anesthetic). The resistance index was calculated. VD and V(mn) were significantly lower during sevoflurane (V(mn) 1.35 m/s) than during halothane (V(mn) 1.50 m/s; P = 0.001), whereas V(s) was unchanged. The resistance index was lower during halothane (P < 0.001). Our results indicate lower vessel resistance and higher mean velocity during halothane than during sevoflurane. IMPLICATIONS: The mean cerebral blood flow velocity is significantly decreased in children during inhaled anesthesia with sevoflurane than during halothane. This might be relevant for the choice of anesthetic in children with risk of increased intracranial pressure, neurosurgery, or craniofacial osteotomies.

Anesthetics, Inhalation↗
PubMed2000

[Interventional treatment of acute myocardial infarct].

BACKGROUND: Randomised trials have shown that primary percutaneous angioplasty (PTCA) may offer advantages over thrombolysis in treating acute myocardial infarction (vessel patency is achieved more often, mortality and reinfarction rate are lower, cerebrovascular accidents are less frequent). Data from several foreign registries have been less clear. Up to now no registry data have been available for Switzerland. Data from registries are very important in planning optimal treatment under "real world" conditions. METHOD: All patients receiving acute PTCA during the first 24 hours of acute myocardial infarction were prospectively included in a registry at a single centre. We assessed times until revascularisation, as well as clinical, angiographic and outcome data. RESULTS: 503 patients (age 59 +/- 12 years, 15% women) were included from 1. 1. 1995 to 30.6.2000. Primary PTCA was performed in 334 patients, and rescue PTCA in 169. Diabetes mellitus was present in 36% of the total. Multivessel disease was present in 61%, anterior infarction in 36%, and 16% were in cardiogenic shock before intervention. The pre-hospital delay was 2:12 h (median). In-hospital decision delay (hospital admission until contact to cardiologist) in patients with primary PTCA was 31 minutes (median). The time from vessel puncture to recanalisation was 19 minutes (median). 273 patients were transferred for coronary angiography and intervention by other hospitals (218 by ground ambulance, 55 per helicopter transfer). The total transfer time (calculated from time of decision to arrival in the catheterization laboratory) was 57 minutes (median). PTCA was successful angiographically in 97% and TIMI 3 flow was obtained in 93% of all patients. Hospital mortality was low in view of the high proportion of patients in cardiogenic shock prior to PTCA (mortality in shock patients was 33%). Mortality in patients without pre-existing cardiogenic shock was 2%. CONCLUSION: Patients with acute myocardial infarction, especially high-risk patients, can be treated successfully by acute PTCA around the clock in Switzerland, in accordance with the strict international recommendations for time delays. The treatment results are similar to those in randomised trials. Transfer of patients from referral hospital is safe, with acceptable delays. Optimisation of the decision process and transport logistics may further improve outcome by reducing the total ischaemia time.

Adult↗
PubMed2000

Cathepsin K expression in human lung.

Tissue remodeling is crucial in different lung diseases, in the embryonal development as well as in bronchial carcinoma. Cathepsins were proposed to be involved in the degradation of matrix proteins. Cathepsin K is one of the most potent matrix-degrading cysteine proteinases known as yet. The elastinolytic and collagenolytic activity of this papain-like protease is comparable with that of neutrophil elastase. We have investigated the cathepsin K expression in normal adult lung tissues, in embryonal lung tissue and in bronchial carcinoma. With help of specific anti-cathepsin K antibodies it could be shown that cathepsin K was expressed in bronchial epithelial cells. These data could be confirmed at mRNA level using a quantitative RT-PCR as well as by visualisation of the specific enzymatic activity in epithelial cell lines. During the embryonal development cathepsin K was expressed in the epithelial cells of the developing bronchi. The expression seemed to be upregulated in parallel with the development of the bronchial and alveolar lumen. In the later phase of lung development the cathepsin K expression was restricted to bronchial epithelial cells. Furthermore, using quantitative RT-PCR it could be shown that cathepsin K-mRNA was upregulated in lung tumor tissues in comparison to normal tissues from the same patients. These data suggest that cathepsin K may play an important role in matrix remodeling of the lung under physiological and pathological conditions.

Bronchi↗
PubMed2000

Expression of cathepsins B and L in human lung epithelial cells is regulated by cytokines.

The cathepsins B, L, and H are expressed ubiquitously and represent the major proportion of lysosomal enzymes. They are involved in bulk proteolysis in the lysosomes, processing of proteins and matrix degradation. Under pathological conditions the participation of cathepsins, especially their secreted forms, was observed in inflammation, tumor progression and metastasis. The enzymatic activity of cathepsins is regulated by posttranslational modification, localization, maturation, changes in pH, and their interaction with inhibitors. Regulation at the level of transcription is not well elucidated. The aim of this study was to investigate the effect of IL-1 beta, IL-6, IL-10, TGF-beta 1, and HGF on mRNA expression and protein level in human lung epithelial cell lines A-549 and BEAS-2B. IL-6 leads to a twofold increase in cathepsin L mRNA expression, whereas TGF-beta 1 decreases the amount of cathepsin L mRNA. At protein level, using enzyme immunoassay, it was shown that IL-6 induced increased amounts of cathepsin L but not cathepsin B. In contrast, after incubation of bronchial epithelial cells with TGF-beta 1 the cathepsin L concentration was decreased. In conclusion, gene expression of cathepsins B and L is variable. The cytokines IL-6 and TGF-beta 1 modulate cathepsin gene expression.

Carcinoma↗
PubMed2000

Comparison of a new video-optical intubation stylet versus the conventional malleable stylet in simulated difficult tracheal intubation.

Handling and efficacy of a new video-optical intubation stylet were assessed in a simulated difficult tracheal intubation setting and compared with a conventional malleable stylet. Forty-five anaesthetists performed 10 tracheal intubations using both techniques. Laryngoscopy was performed by the observer, who created a grade 3 view according the classification by Cormack and Lehane. The time taken to place the tracheal tube and the final tracheal tube positions were documented. Mean (SD) intubation time for the video-optical stylet was 20.4 (7.7) s and for the malleable stylet 10.2 (3.3) s (p<0.01). With the video-optical stylet the trachea was correctly intubated in all 225 attempts; with the malleable stylet 44 (19.6%) oesophageal and 44 (19.6%) endobronchial intubations occurred (p<0.01). The video-optical intubation stylet enabled us to recognise inappropriate tracheal tube positions and to correct them immediately. This equipment can be considered a reliable and effective tool for management of the difficult airway.

Computer Terminals↗
PubMed2000

Staphylococcal alpha-toxin: repair of a calcium-impermeable pore in the target cell membrane.

Staphylococcal alpha-toxin forms heptameric pores that render membranes permeable for monovalent cations. The pore is formed by an amphipathic beta-barrel encompassing amino acid residues 118-140 of each subunit of the oligomer. Human fibroblasts are susceptible to alpha-toxin but are able to repair the membrane lesions. Thereby, toxin oligomers remain embedded in the plasma membrane and exposed to the extracellular medium. In this study, we sought to detect structural changes occurring in the pore-forming sequence during lesion repair. Single cysteine substitution mutants were labelled with the environmentally sensitive fluorochrome acrylodan and, after mixing with wild-type toxin, incorporated into hybrid heptamers on fibroblast membranes. Formation of the lipid-inserted beta-barrel was accompanied by characteristic fluorescence emission shifts. After lesion repair, the environment of the residues at the outer surface of the beta-barrel remained unchanged, indicating continued contact with lipids. However, the labelled residues oriented towards the channel lumen underwent a green to blue shift in fluorescence, indicating reduced exposure to water. Pore closure proceeded in the presence of calmodulin inhibitors and of microtubule disruptors; however, it was prevented by cytochalasin D and by inhibitors of lipid metabolism. Our findings reveal the existence of a novel mechanism of membrane repair that may consist in constriction of the inserted proteinaceous pore within the lipid bilayer.

Bacterial Toxins↗
PubMed2000

Effect of granulocyte colony-stimulating factor treatment on ex vivo neutrophil functions in nonneutropenic surgical intensive care patients.

Granulocyte colony-stimulating factor (G-CSF) preferentially stimulates growth and differentiation of neutrophil precursors and activates neutrophil functions. The aim of the present study was to investigate the functional response of the neutrophil to exogenous recombinant human G-CSF (rHuG-CSF) in nonneutropenic patients. In 30 surgical intensive care unit patients with severely impaired wound healing, leukocyte differential count, plasma G-CSF level, and a broad spectrum of neutrophil functions were monitored before (day 0), throughout (days 1 and 5), and at days 1 and 5 after stopping G-CSF treatment. G-CSF application resulted in a 3.5-fold increase in peripheral blood granulocyte count at day 5 of treatment. The mean plasma G-CSF level rose from 48 to a maximum of 2314 pg/ml at day 1 of G-CSF therapy. Neutrophil chemotaxis and stimulated lysozyme release were decreased throughout G-CSF treatment, whereas respiratory burst activity, phagocytic activity, and intracellular calcium concentration were enhanced by G-CSF. Neutrophil membrane depolarization remained unaffected. The increased count and activation state of neutrophils were associated with clinical improvement in most of these patients. Thus, G-CSF may be a useful adjuvant treatment for nonneutropenic patients with severely impaired wound healing.

Adult↗
PubMed2000

Remifentanil inhibits muscular more than cutaneous pain in humans.

In experimental studies, drug-induced analgesia is usually assessed by cutaneous stimulation. If analgesics act differently on cutaneous and deep nociception, the results of these studies may not be entirely applicable to clinical pain involving deep structures. We tested the hypothesis that opioids have different abilities to inhibit cutaneous and muscular pain. Either the opioid remifentanil or placebo was infused in 12 healthy volunteers in a cross-over fashion. Repeated electrical stimulation (five impulses at 2 Hz) was applied to both skin and muscle. Pain thresholds were recorded. Remifentanil caused a higher increase in the muscular pain thresholds than in the cutaneous pain thresholds (P = 0.035). We conclude that opioids inhibit muscular pain more strongly than cutaneous pain in humans.

Adult↗
PubMed2000

Impact of infusion line compliance on syringe pump performance.

To determine the impact of infusion line compliance on the time to occlusion alarm (occlusion time) and the size of the subsequent occlusion release bolus, we studied three different infusion lines in combination with a 50-ml and 10-ml syringe. The mean occlusion time of the 50-ml syringe amounted to 20.3 +/- 0.28 min and increased to 26.2 +/- 0.19 min with the infusion with the infusion line yeielding the largest compliance (P<0.0001). The mean occlusion time of the 10-ml syringe was 2.5 +/- 0.75 min and showed a 2.7-fold variation with the three infusion lines (2.6+/-0.08, 5.6 +/- 0.28 and 6.9 +/- 0.35 min, respectively; P<0.0001). Occlusion times correlated strongly to be calculated estimated compliance of the syringe-infusion line assembly (Pearson's r=0.998, P<0.0001). Infusion line compliance has an important impact on time to occlusion, particularly when using small, low compliant infusion pump syringes.

Compliance↗
PubMed2000

Investigation of annexin V binding to lymphocytes after extracorporeal photoimmunotherapy as an early marker of apoptosis.

BACKGROUND: Induction of programmed cell death is assumed to be a possible effect of extracorporeal photoimmunotherapy (ECPI). OBJECTIVE: In the present study lymphocytes of patients with cutaneous T cell lymphoma undergoing ECPI were investigated for early apoptotic events. METHODS: Annexin V, known for its selective affinity to phospholipids, was used to detect early phases of apoptosis. Simultaneous staining with propidium iodide binding to DNA allowed detection of late apoptotic/necrotic cells. RESULTS: At 1 h after ECPI, an increase in early apoptotic cells was found indicating a direct effect of ECPI. At 20 h after each ECPI session, a delayed increase in the number of apoptotic lymphocytes was observed in early apoptotic annexin-stained cells and in late apoptotic cells, whereas in nonirradiated cells no remarkable changes were found. Apoptosis was confirmed by altered light scattering properties and DNA fragmentation. CONCLUSION: The apoptotic cell death of reinfused lymphocytes is supposed to be a therapeutic effect of ECPI.

Aged↗
PubMed1999

Editing of messenger RNA precursors and of tRNAs by adenosine to inosine conversion.

The double-stranded RNA-specific adenosine deaminases ADAR1 and ADAR2 convert adenosine (A) residues to inosine (I) in messenger RNA precursors (pre-mRNA). Their main physiological substrates are pre-mRNAs encoding subunits of ionotropic glutamate receptors or serotonin receptors in the brain. ADAR1 and ADAR2 have similar sequence features, including double-stranded RNA binding domains (dsRBDs) and a deaminase domain. The tRNA-specific adenosine deaminases Tad1p and Tad2p/Tad3p modify A 37 in tRNA-Ala1 of eukaryotes and the first nucleotide of the anticodon (A 34) of several bacterial and eukaryotic tRNAs, respectively. Tad1p is related to ADAR1 and ADAR2 throughout its sequence but lacks dsRBDs. Tad1p could be the ancestor of ADAR1 and ADAR2. The deaminase domains of ADAR1, ADAR2 and Tad1p are very similar and resemble the active site domains of cytosine/cytidine deaminases.

Adenosine↗
PubMed1999

The expression of plasma membrane Ca2+ pump isoforms in cerebellar granule neurons is modulated by Ca2+.

Plasma membrane Ca2+ ATPase (PMCA) pump isoforms 2, 3, and 1CII are expressed in large amounts in the cerebellum of adult rats but only minimally in neonatal cerebellum. These isoforms were almost undetectable in rat neonatal cerebellar granule cells 1-3 days after plating, but they became highly expressed after 7-9 days of culturing under membrane depolarizing conditions (25 mM KCl). The behavior of isoform 4 was different: it was clearly detectable in adult cerebellum but was down-regulated by the depolarizing conditions in cultured cells. 25 mM KCl-activated L-type Ca2+ channels, significantly increasing cytosolic Ca2+. Changes in the concentration of Ca2+ in the culturing medium affected the expression of the pumps. L-type Ca2+ channel blockers abolished both the up-regulation of the PMCA1CII, 2, and 3 isoforms and the down-regulation of PMCA4 isoform. When granule cells were cultured in high concentrations of N-methyl-D-aspartic acid, a condition that increased cytosolic Ca2+ through the activation of glutamate-operated Ca2+ channels, up-regulation of PMCA1CII, 2, and 3 and down-regulation of PMCA4 was also observed. The activity of the isoforms was estimated by measuring the phosphoenzyme intermediate of their reaction cycle: the up-regulated isoforms, the activity of which was barely detectable at plating time, accounted for a large portion of the total PMCA activity of the cells. No up-regulation of the sarcoplasmic/endoplasmic reticulum calcium pump was induced by the depolarizing conditions.

Animals↗