The influence of obstructive sleep apnea and continuous positive airway pressure on the nasal microbiome

OBJECTIVE

The aim of this study was to investigate the influence of obstructive sleep apnea and continuous positive airway pressure on the nasal microbiome.

PATIENTS AND METHODS

Endonasal swabs from the olfactory groove of 22 patients with moderate and severe obstructive sleep apnea (OSA) and a control group of 17 healthy controls were obtained at the Department of Otorhinolaryngology of the Friedrich-Alexander-Universität Erlangen-Nürnberg. 16S rRNA gene sequencing was performed to further evaluate the endonasal microbiome. In a second step, the longitudinal influence of continuous positive airway pressure (CPAP) therapy on the nasal microbiome was investigated (3-6 and 6-9 months).

RESULTS

Analysis of the bacterial load and β-diversity showed no significant differences between the groups, although patients with severe OSA showed increased α-diversity compared to the control group, while those with moderate OSA showed decreased α-diversity. The evaluation of longitudinal changes in the nasal microbiota during CPAP treatment showed no significant difference in α- or β-diversity. However, the number of bacteria for which a significant difference between moderate and severe OSA was found in the linear discriminant analysis decreased during CPAP treatment.

CONCLUSIONS

Long-term CPAP treatment showed an alignment of the composition of the nasal microbiome in patients with moderate and severe OSA as well as an alignment of biodiversity with that of the healthy control group. This change in the composition of the microbiome could be both part of the therapeutic effect in CPAP therapy and a promoting factor of the adverse side effects of the therapy. Further studies are needed to investigate whether the endonasal microbiome is related to CPAP compliance and whether CPAP compliance can be positively influenced in the future by therapeutic modification of the microbiome.

Active, artificial hair cells for biomimetic sound detection based on active cantilever technology

We aim at building and studying artificial hair cells (AHC) based on MEMS technology to understand the extraordinary sound perception of the human ear and build a sensor system with similar properties. These perception properties, i.e. detecting six orders of sound pressure level and simultaneously frequency differences of only 3-5 Hz, are obtained mainly due to the sophisticated biological sensors in the inner ear, called hair cells, which convert the acoustic waves into electric signals. They amplify weak inputs and compress larger ones, known as compressive nonlinearity, thus enabling this impressive dynamic range, typically not captured by current engineering solutions. We tackle this demand by building artificial hair cells on the basis of smart, self-actuated and self-sensing mechanical resonator beams with suitable actuation feedback. Thereby, we take advantage of the fact that the compressive nonlinearity arises naturally in dynamical systems tuned to a bifurcation point. This tuning is achieved by an appropriate feedback loop inspired by physiological models. Initial results on the detection properties of a single AHC will be shown demonstrating amplification and a decreased width of the resonance peak.

[Instruction in medical ethics during clinical training for medical students: report on experience in radio-oncology]

The article gives a review of the current state of education in medical ethics in Germany. The issue is considered from the viewpoint of radio-oncology. Both the pertinent literature and our own experience in teaching medical ethics are presented. In October 2003, medical ethics was integrated into the curriculum of medicine. The aim was to train competence in the field of personal attitudes and to intensify skills of moral reasoning. Our own experiences are positive, which is in accordance with the reports of other working groups. Most of the students were interested in education in medical ethics and looked upon ethical training as being an important part of their studies. Medical students are interested in ethical education during the clinical period of their studies, which has been taken into account since the actual change of the curriculum. Radio-oncologists as specialists in other clinical fields can offer important contributions when they discuss clinical cases from the viewpoint of medical ethics. The long-term effect of such an education will become the subject of future research.

[Ethics and diagnosis related groups]

At the turn of the year 2003/2004 a change took place in the in-patient sector of the German public health care system from the former daily-rate-based reimbursement of medical services to a reimbursement in accordance with diagnosis related groups (DRGs). At the same time, there are indications for a paradigm change in the allocation of medical services: away from the even provision of medical care across all country's municipalities towards a concentration in specialized medical centres - with uncertain ethical implications. On one hand, one hopes to cut costs in the in-patient area. On the other hand, it is questionable, whether cutting costs still allows an adequate treatment of multimorbid, chronically ill patients. The new system likely favours the active, autonomously deciding patient, who is capable of using additional information from the planned quality reports to obtain the best possible medical services. But the new system could create a disadvantage for the less informed patient groups, especially those who don't have easy access to such information. It is not our intention to idealise the German health care system before the invention of diagnosis related groups. Based on a survey of studies from the U.S., the article assesses consequences of such a system and relates them to ethical considerations.

Ethics, EBM, and hospital management

Matters of hospital management do not figure prominently on the medical ethics agenda. However, management decisions that have to be taken in the area of hospital care are in fact riddled with ethical questions and do have significant impact on patients, staff members, and the community being served. In this decision making process evidence based medicine (EBM) plays an increasingly important role as a tool for rationalising as well as rationing health care resources. In this article, ethical issues of hospital management and the role of EBM will be explored, with particular reference to disease management programs, diagnosis related groups, and clinical pathways as recent developments in the German health care system.

Non-therapeutic research with minors: how do chairpersons of German research ethics committees decide?

OBJECTIVES

Clinical trials in humans in Germany-as in many other countries-must be approved by local research ethics committees (RECs). The current study has been designed to document and evaluate decisions of chairpersons of RECs in the problematic field of non-therapeutic research with minors. The authors' purpose was to examine whether non-therapeutic research was acceptable for chairpersons at all, and whether there was certainty on how to decide in research trials involving more than minimal risk.

DESIGN

In a questionnaire, REC chairpersons had to evaluate five different scenarios with (in parts) non-therapeutic research. The scenarios described realistic potential research projects with minors, involving increasing levels of risk for the research participants. The chairpersons had to decide whether the respective projects should be approved.

METHODS

A total of 49 German REC chairpersons were sent questionnaires; 29 questionnaires were returned. The main measurements were approval or rejection of research scenarios.

RESULTS

Chairpersons of German RECs generally tend to accept non-therapeutic research with minors if the apparent risk for the participating children is low. If the risk is clearly higher than "minimal", the chairpersons' decisions differ widely.

CONCLUSION

The fact that there seem to be different attitudes of chairpersons to non-therapeutic research with minors is problematic from an ethical point of view. It suggests a general uncertainty about the standards of protection for minor research participants in Germany. Therefore, further ethical and legal regulation of non-therapeutic research with minors in Germany seems necessary.

Long-term effects of Helicobacter pylori eradication on gastric antral mucosa in duodenal ulcer patients

OBJECTIVES

The aim of this study was to assess the consequences of prolonged Helicobacter pylori eradication on gastric antral mucosa in duodenal ulcer patients.

PATIENTS AND METHODS

Forty-three duodenal ulcer patients with confirmed H. pylori eradication after one year of follow-up were included in this retrospective study. Before H. pylori eradication and during the follow-up, four antral prepyloric biopsy samples were taken for histopathological examination and culture. Histopathological lesions were graded semi-quantitatively according to the updated Sydney System for activity, chronic inflammation, glandular atrophy and intestinal metaplasia (IM), as well as presence of lymphoid follicles.

RESULTS

After a mean follow-up of 43 +/- 23 months, H. pylori eradication statistically improved all gastritis scores, including the atrophy score and the lymphoid follicle score but excluding the IM score. H. pylori eradication resulted in normalization of gastric mucosa in 51.2% of patients and a significantly lower proportion of patients with non-atrophic gastritis and atrophic gastritis without IM. Atrophy totally disappeared in 16/29 patients (55.2%) in whom IM was absent. No predictive factor for regression of atrophy or normalization of gastric mucosa was identified.

CONCLUSION

In duodenal ulcer patients, prolonged absence (more than one year) of H. pylori can lead to normalization of the antral mucosa and the disappearance of mucosa-associated lymphoid tissue, as well as the regression of antral atrophy. Long-term studies involving selected patients with atrophy and IM which persist after H. pylori eradication are needed to determine the potential benefits of treating H. pylori gastritis with regard to gastric cancer prevention.

Neuronal and inducible nitric oxide synthase distribution in retinas of microphthalmic mice

A study about the distribution of neuronal nitric oxide synthase (n-NOS) and inducible NOS (i-NOS) was performed in microphthalmic retinas at postnatal day (pd) 2 and pd 7. Neither n-NOS nor i-NOS immunoresponse could be detected at pd 2. At pd 7, i-NOS activity was revealed in the retinas of mi/mi littermates but not in those of heterozygotes or wild-type littermates. The expression of n-NOS corresponded to the postnatal retinal development. Retinal rosettes were strongly labelled.

Retinoblastoma protein in microphthalmic mice

A microphthalmic strain of mice was used to study immunoresponse of the retinoblastoma protein. Comparing wild-type, heterozygote and homozygote microphthalmic eyes, we found an increasing labelling of phosphorylated retinoblastoma protein (pRb) in the retinal pigment epithelium. Additionally, microphthalmic eyes expressed pRb in the neuroepithelium. Especially rosettes were strongly labelled.

[Adenoma of the choledochus]

Two patients with signs of an obstructed main bile duct underwent surgery. Choleductectomy was performed followed by Mirizzi exploration. Extemporaneous pathology examination of the intra-ductal tissue revealed benign adenoma of the main bile duct. Resection of the main bile duct with hepato-duodenal anastomosis was performed in the first patient and resection with end-to-end anastomosis in the second.

[Effect of postmortem duration on endothelial cell density in short-term culture with McCarey-Kaufman medium. An experimental study with Swine corneas]

It is recommended by the Eye Bank Association of American that the post-mortem time of donor tissue stored in intermediate storage should not exceed 6 h. In an experimental study we investigated the impact of post-mortem time on the storage of corneas kept in McCarey-Kaufman medium. Eyeballs of freshly slaughtered pigs were kept in moist chamber storage at 4 degrees C for 0, 6, 12, 24, and 48 h. Subsequently, corneal-scleral rims were dissected and stored in MK-Medium for 2 days at 4 degrees C. The corneas were stored in organ culture for another 2 days at 31 degrees C in MEM medium containing 10% fetal calf serum. A control group consisted of corneas that had been stored in organ culture for 2 days. Morphometric analysis revealed no significant changes in endothelial cell density compared to control corneas after up to 24 h of moist chamber storage prior to storage in MK medium. A significant decrease in endothelial cell density could only be detected in corneas that had been kept in moist chamber storage for 48 h before MK medium storage. We conclude that the recommendation that only donor corneas with short post-mortem times be used may exclude large amounts of potentially feasible tissue for penetrating keratoplasty.

[Behavior of human rib and patella cartilage]

Report is based on compression- and relaxation experiments with 90 rib- and 30 patella cartilage samples of different aged human bodies to evaluate the elastic and viscoelastic response. The results indicate biomechanical similarities and differences between patella-and rib cartilage as well as in the several age groups. In all age group we could obtain that rib cartilage is "stiffer" than patella cartilage and a loosening in capacity of tensional reduction with increasing age.

Precambrian Age of the Boston Basin: New Evidence from Microfossils

A Vendian (Late Proterozoic Z) age has been determined for the Boston Basin by comparison of a microflora from the Cambridge Argillite with other late Precambrian assemblages. The microfossils, which include Bavlinella cf. faveolata, are preserved as petrifactions in pyrite. This age designation for the sedimentary rocks of the Boston Basin should allow for the reinterpretation of the structure of the basin and its regional correlations.