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Biomedical subjects

N Moser

Publications and source records attributed to N Moser.

17 recordsLinked to original sources
PubMed2006

[Transport of blood gas samples: is the pneumatic tube system safe?].

BACKGROUND: Transport of blood gas samples via a pneumatic tube system and subsequent analysis in the central laboratory can reduce costs and errors compared to on-site testing in the operating theatre or the intensive care unit. In this study, a modern pneumatic tube transport system was tested for its usability for this purpose. METHODS: A total of 4 consecutive blood gas samples were obtained intraoperatively from 54 different patients and sent to the central laboratory. Of these, 3 samples were transferred using the pneumatic tube system but by different methods and 1 sample was transported personally which served as a reference. The results of sample analysis concerning blood gases, electrolytes and haemoglobin were compared and examined for differences. RESULTS: No statistically significant differences could be determined between the different modes of transportation. CONCLUSION: Transport of samples for blood gas analysis via a modern pneumatic tube system is safe when samples are correctly prepared.

Analysis of Variance↗
PubMed2003

Time to progression is dependent on the expression of the tumour suppressor PTEN in ovarian cancer patients.

BACKGROUND: Quantitative analyses of PTEN expression of ovarian cancer tissues were performed in this study. PTEN expression was investigated in terms of each patient's progression-free interval to indicate the role of PTEN in the generation of platinum refractory tumours. MATERIALS AND METHODS: The study group comprised 20 ovarian cancer patients from whom fresh frozen tissues of both the primary tumour and specimens of progressive disease were available. The PTEN protein and phosphorylation of the downstream effector protein kinase B (PKB) were quantified by Western blot analyses and subsequent densitometry. Data were analyzed for individual PTEN variation with respect to the clinical course as defined by the progression-free interval. RESULTS: Applying the usual clinical criteria for platinum-sensitivity after progression, seven patients were considered platinum-sensitive whereas 13 patients had suffered a progression within 12 months after the chemotherapy. In 5/7 (71%) cases with prolonged time to progression, an increase in PTEN was observed. Decline of PTEN expression occurred in 9/13 (69%) patients with poor outcome. PTEN expression corresponds inversely to PKB phosphorylation in 14/20 (70%) tissues investigated. CONCLUSIONS: The data suggest that decreased PTEN expression accompanies the progression of ovarian cancer. Declining PTEN expression results in a shortened relapse-free interval, whereas an increase of PTEN prolongs the time to progression. However, as far as recurrence occurs, PTEN is not the only mechanism to suppress tumour progression in ovarian cancer.

Adult↗
PubMed2001

Expression of the alpha4 isoform of the nicotinic acetylcholine receptor in the fetal human cerebral cortex.

Nicotinic acetylcholine receptors are likely to play an important role in neuronal migration during development. Furthermore, the alpha4 receptor subunit gene is related to a hereditary juvenile form of epilepsy. Only little information is available, however, on the expression of cerebrocortical nicotinic acetylcholine receptors during human fetal development. Using non-isotopic in situ hybridization and immunohistochemistry, we have studied the distribution of the alpha4 subunit of the nicotinic acetylcholine receptor mRNA and protein in the human frontal cortex at middle (17-24 weeks of gestation) and late (34-42 weeks of gestation) fetal stages. Both, alpha4 receptor mRNA and alpha4 receptor protein were observed beginning during week 17-18 of gestation. At this time of development, a few weakly labeled mRNA-containing cells were present mainly in the ventricular zone, the subplate and the cortical plate. A similar distribution pattern was found for the receptor protein. Around week 38 of gestation, the distribution in the cerebral cortex of alpha4 subunit-containing cells was similar to that of adult human cortices with the highest densities of labeled neurons found in layers II/III, followed by layers V and VI. Nicotinic acetylcholine receptor-containing neurons appear rather early in human fetal development. Given functional maturity, they may interact during cortical development with acetylcholine released from corticopetal fibers or other yet unknown sources subserving the process of neuronal migration and pathfinding.

Animals↗
PubMed2001

Parvalbumin-containing interneurons of the human cerebral cortex express nicotinic acetylcholine receptor proteins.

Cholinergic fibers from the basal forebrain are known to contact cholinoceptive cortical pyramidal neurons. Recent electrophysiological studies have revealed that nicotinic acetylcholine receptors are also present in human cerebrocortical interneurons. A direct visualization of nicotinic receptor subunits in cortical interneurons has, however, not yet been performed. We have applied double-immunofluorescence using antibodies against parvalbumin --a marker for the Chandelier and basket cell subpopulation of interneurons--and to the alpha4 and alpha7 subunit proteins of the nicotinic acetylcholine receptor. The vast majority of the parvalbuminergic interneurons was immunoreactive for the alpha4 and the alpha7 nicotinic acetylcholine receptor. Provided these receptors would be functional--as suggested by recent electrophysiological findings--the connectivity pattern of cholinergic afferents appears much more complex than thought before. Not only direct cholinergic impact on cortical projection neurons but also the indirect modulation of these by cholinergic corticopetal fibers contacting intrinsic cortical cells would be possible.

Adult↗
PubMed2000

Expression of nicotinic acetylcholine receptors in Alzheimer's disease: postmortem investigations and experimental approaches.

Nicotinic ligand binding studies have shown rather early that the cholinoceptive system is affected in Alzheimer's disease (AD). Today, molecular histochemistry enables one to study the nicotinic acetylcholine receptor (nAChR) subunit expression on the cellular level in human autopsy brains, in animal models and in in vitro approaches, thus deciphering the distribution of nAChRs and their role as potential therapeutic targets. The studies on the nAChR expression in the frontal and temporal cortex of AD patients and age-matched controls could demonstrate that both, the numbers of alpha4- and alpha7-immunoreactive neurons and the quantitative amount, in particular of the alpha4 protein, were markedly decreased in AD. Because the number of the corresponding mRNA expressing neurons was unchanged these findings point to a translational/posttranslational rather than a transcriptional event as an underlying cause. This assumption is supported by direct mutation screening of the CHRNA4 gene which showed no functionally important mutations. To get more insight into the underlying mechanisms, two model systems organotypic culture and primary hippocampal culture - have been established, both allowing to mimic nAChR expression in vitro. In ongoing studies the possible impact of beta-amyloid (Abeta) on nAChR expression is tested. Preliminary results obtained from primary cultures point to an impaired nAChR expression following Abeta exposure.

Aged↗
PubMed2000

Classical Alzheimer features and cholinergic dysfunction: towards a unifying hypothesis?

OBJECTIVE: Our autopsy studies show possible links between classical Alzheimer pathology and decreased expression of nicotinic acetylcholine receptors. For further elucidation we are now using in vitro models. We report preliminary evidence for the impact of beta-amyloid on nicotinic receptor expression in hippocampal dissociation culture. METHODS: Cultures (E18 rats) were grown in a serum-free medium and incubated at 8 days in vitro for 3 days with 1 microM Abeta1-42. Expression of alpha4, alpha7, and beta2 nicotinic receptor subunit protein was assessed immunohistochemically and rated semiquantitatively. RESULTS: Abeta1-42 incubation resulted in a massive reduction of alpha4 protein-expressing neurons, this effect was less pronounced for the alpha7 and beta2 subunit protein. CONCLUSION: These findings provide first evidence for a direct impact of classical Alzheimer pathology features on nicotinic receptor expression in vitro. Our model will be useful for testing the potential of drugs to stop or reverse these effects.

Alzheimer Disease↗
PubMed1998

[Validation of the "Digest Questionnaire" for consistency and reproducibility with reference to upper abdominal symptoms].

"Digest" is a international effort to record the prevalence of digestive symptoms in the general population. The international questionnaire was tested in German translation for reliability and reproducibility. The questionnaire consists of 14 symptoms, which were investigated by standardized questions. Each symptom was described in 3 dimensions: frequency, severity and impact on daily activities. 127 successive patients referred for upper gastrointestinal endoscopy were interviewed twice by a young assistant and by an experienced gastroenterologist before the diagnostic work-up. A further 72 volunteers served as a control group. In these volunteers no upper gastrointestinal endoscopy was performed. Reliability and reproducibility were calculated by the Spearman rank test. The most frequent diagnoses were: organic diseases (oesophagitis [28], gastric ulcer/erosive gastritis [32] and duodenal ulcer [18]); functional diseases (dyspepsia [32] and irritable bowel syndrome [14]). Reproducibility was satisfactory by accepted standards (p > 0.7). Reliability was very good, with r-values for each symptom between p 0.96-0.99. The impact on daily activities was highest in the case of heart-burn or localized upper gastrointestinal pain, and lowest in the case of belching and fullness. The questionnaire can be easily administered by the non-specialist and the results discriminate well between functional/organic diseases and healthy people, thanks to excellent reproducibility and reliability.

Activities of Daily Living↗
PubMed1997

A synthetic model for microsurgical training: a surgical contribution to reduce the number of animal experiments.

Microsurgery has grown to be an essential technique in pediatric surgery. Thus, there is an increasing need for basic training and skills maintenance, which require a continuous laboratory training. As an alternative to microsurgical exercises on living animals, a model including a simulation vein, artery and nerve is being introduced. It provides an opportunity to practice microsurgical technique with optimal availability at any time at fairly low cost. Its potentials and limits in the training of microsurgical dissection, anastomosis and quality control are being compared to experiments on anesthetized animals. Although a few exercises on living animals are mandatory to close the gap between the laboratory and the patient, a synthetic model is a valuable tool in microsurgical training and helps to reduce animal experiments.

Anastomosis, Surgical↗
PubMed1997

Muscle biopsy for malignant hyperthermia screening in children.

Malignant Hyperthermia (MH) remains a life-threatening event in anaesthetic practice. In paediatric patients, triggering agents such as volatile anaesthetics and other succinylcholine are widely used. For children with a positive family history or previous clinical signs of MH, muscle biopsy for the halothane and caffeine in vitro muscle contracture tests is the only reliable procedure for diagnosis of MH susceptibility. Here we investigated outcome and compliance of patients and parents involved in the test. Twenty-four children between 6 and 14 yrs of age were admitted to hospital for biopsy. Muscle withdrawal was performed at the upper leg from lateral vastus muscle using regional or trigger-free general anaesthesia. Outcome and compliance were controlled by a telephone interview or direct physical re-evaluation. Seventeen patients out of 24 were diagnosed as clinically MH-susceptible according to the protocol of the European MH Group. Seven children were excluded as MH-negative by the test. Twenty-one children were evaluated postoperatively. Minor side effects of wound healing occurred, but none of the patients showed any abnormalities of muscle contracture or movement performance. Considering the high risk of fatal complications in the presence of MH-susceptibility, muscle biopsy of the upper leg for in-vitro diagnosis is a justified procedure that is acceptable to children and their parents.

Adolescent↗
PubMed1996

Alpha4-1 subunit mRNA of the nicotinic acetylcholine receptor in the rat olfactory bulb: cellular expression in adult, pre- and postnatal stages.

In addition to their role in signal transduction, nicotinic acetylcholine receptors have been shown in vi-tro to be involved in neuronal growth cone regulation during development. This idea is supported by recent histochemical findings showing that iso- and archicortical nicotinic alpha4-1 receptor mRNA expression precedes cholinergic fiber ingrowth. To test whether this also holds true for rhinencephalic parts of the telencephalon, we have studied the olfactory bulb by digoxigenin-mediated in situ hybridization, using an alpha4-1 isoform-specific riboprobe and an alkaline-phosphatase-based detection system. Development is characterized by early intense alpha4-1 mRNA expression (embryonic day 14), reaching a peak around postnatal day 2 when all olfactory bulb layers are invested with numerous alpha4-1 transcript-bearing neurons. Subsequently, the density of labeled neurons decreases to reach adult levels (postnatal day 120), where strongly labeled neurons remain in the mitral cell layer, outer external plexiform layer, and glomerular layer. The unifying pattern of iso-, archicortical, and rhinencephalic alpha4-1 mRNA expression is its early onset, i.e. preceding cholinergic innervation. This points to a possible role of nicotinic receptors regarding neuronal migration in all three regions.

Animals↗
PubMed1996

Clinical and imaging features of pulmonary strongyloidiasis.

We evaluated 20 patients with pulmonary strongyloidiasis for risk factors, clinical and imaging manifestations, complications, treatment, and outcome. Eighteen (90%) had risk factors for strongyloidiasis including steroid use, age greater than 65, chronic lung disease, use of histamine blockers, or chronic debilitating illness. Pulmonary signs and symptoms, including cough, shortness of breath, wheezing, and hemoptysis, were present in 19 (95%); adult respiratory distress syndrome (ARDS) developed in 9 (45%). Pulmonary infiltrates occurred in 18 (90%). Gastrointestinal signs and symptoms were also common. Peripheral blood eosinophilia occurred in 15 (75%). Twelve (60%) had secondary infection, and 3 (15%) had bacterial lung abscesses. All were treated with thiabendazole, 25 mg/kg twice daily; on average, patients without ARDS were treated for 3 days, versus 7 days for those with ARDS. Seventy percent responded to therapy; 30% died. Preexisting chronic lung disease and ARDS were statistically significant predictors of a poor prognosis.

Adolescent↗
PubMed1996

[A new method for treating the Kirner deformity with the SM-Fix phalangeal distractor].

The Kirner deformity belongs to the rare bony deformities of the small finger. The present treatments range from hemiepiphysiodesis to osteotomy with bone-grafting. We present a ten-year-old girl with a unilateral Kirner deformity treated in a new fashion. Through a distal phalanx osteotomy and the use of a SM-Fix-phalangeal distractor, bridging the distal interphalangeal joint, the axis was corrected. After four to five weeks the defect was filled by callus distraction. The advantage of this method is not only the minimal traumatisation of the juvenile distal phalanx but also the functional and cosmetic results.

Bone Lengthening↗