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Biomedical subjects

M Geyer

Publications and source records attributed to M Geyer.

At least 19 recordsLinked to original sources
PubMed2006

Magnetic resonance imaging scans for vestibulocochlear nerve tumours: what is actually found?

BACKGROUND: Approximately 20 per cent of adult patients presenting to otolaryngology clinics have symptoms pertaining to the inner ear. These are investigated with magnetic resonance imaging (MRI) internal auditory meatus scans. This study analysed all findings from 736 sequential MRI internal auditory meatus scans performed on 731 patients over a one year period. METHODS: Six hundred and seventy-two patients were included for analysis. Of these, 419 (62.35 per cent) had normal MRI scans, 221 (32.90 per cent) had MRI findings thought to be unrelated to their presenting symptoms, 32 (4.76 per cent) had findings thought to be the cause of their symptoms, and eight (1.19 per cent) had the typical appearance of an VIIIth nerve schwannoma. CONCLUSIONS: Magnetic resonance image scanning of the inner ears and auditory pathways yields a diagnosis of VIIIth nerve tumours of the order of 1 per cent, does not show other causes of inner-ear symptoms in a further 4 per cent, and shows incidental intra- and extracranial abnormalities in a further 33 per cent, most of which are not clinically significant.

Aged↗
PubMed2006

[Epidemiology of gastrointestinal bleeding in the elderly].

The epidemiological pattern of gastrointestinal bleed in western countries has been steadily changing over the last few years given the rising prevalence of an elderly population. In a one year prospective study at a referral hospital in Zurich, Switzerland, hospitalised patients were investigated with regards to the epidemiology of gastrointestinal (GI) bleeding. Of 7406 hospitalisations, a total number of 224 GI bleeds were registered (53% women, mean age 71 +/- 16, 63% with relevant co morbidities). Of 197 patients with GI bleeds, 51% had upper and 37% lower gastrointestinal bleedings. 2% had concurrent upper and lower gastrointestinal bleedings and 10% remained unexplained. The following spectrum of lesions identified as bleeding sources was: 24% ulcer bleedings, 16% diverticular bleedings, 10% colitis, 10% esophagitis and 6% Mallory-Weiss lesions. The frequency of bleeds significantly increased with patient's age. In addition, diverticular bleeding in the elderly was highly associated with intake of Aspirin. The prognosis of gastrointestinal bleeding in elderly patients in this study was excellent with a bleeding associated mortality of only 3.1%.

Age Factors↗
PubMed2006

Primary mouse hepatocytes for systems biology approaches: a standardized in vitro system for modelling of signal transduction pathways.

Complex cellular networks regulate regeneration, detoxification and differentiation of hepatocytes. By combining experimental data with mathematical modelling, systems biology holds great promises to elucidate the key regulatory mechanisms involved and predict targets for efficient intervention. For the generation of high-quality quantitative data suitable for mathematical modelling a standardised in vitro system is essential. Therefore the authors developed standard operating procedures for the preparation and cultivation of primary mouse hepatocytes. To reliably monitor the dynamic induction of signalling pathways, the authors established starvation conditions and evaluated the extent of starvation-associated stress by quantifying several metabolic functions of cultured primary hepatocytes, namely activities of glutathione-S-transferase, glutamine synthetase, CYP3A as well as secretion of lactate and urea into the culture medium. Establishment of constant metabolic activities after an initial decrease compared with freshly isolated hepatocytes showed that the cultured hepatocytes achieve a new equilibrium state that was not affected by our starving conditions. To verify the highly reproducible dynamic activation of signalling pathways in the in vitro system, the authors examined the JAK-STAT, SMAD, PI3 kinase, MAP kinase, NF-kappaB and Wnt/beta-catenin signalling pathways. For the induction of gp130, JAK1 and STAT3 phosphorylation IL6 was used, whereas TGFbeta was applied to activate the phosphorylation of SMAD1, SMAD2 and SMAD3. Both Akt/PKB and ERK1/2 phosphorylation were stimulated by the addition of hepatocyte growth factor. The time-dependent induction of a pool of signalling competent beta-catenin was monitored in response to the inhibition of GSK3beta. To analyse whether phosphorylation is actually leading to transcriptional responses, luciferase reporter gene constructs driven by multiple copies of TGFbeta-responsive motives were applied, demonstrating a dose-dependent increase in luciferase activity. Moreover, the induction of apoptosis by the TNF-like cytokine Fas ligand was studied in the in vitro system. Thus, the mouse hepatocyte in vitro system provides an important basis for the generation of high-quality quantitative data under standardised cell culture conditions that is essential to elucidate critical hepatocellular functions by the systems biology approach.

Animals↗
PubMed2006

How we do it: patient participation in cochlear implant selection.

. Involving patients and parents in the choice of their cochlear implant encourages an active role in the process and facilitates 'bonding' and 'ownership' of the device. . The most frequent reasons given by patients for selecting a device included cochlear implant comfort and appearance. . We describe the Implant Programme based at the Royal National Throat, Nose and Ear Hospital, London, and also examine patient satisfaction with the scheme.

Adult↗
PubMed2005

[Achillodynia].

Achilles tendinitis and posterior heel pain are caused by a wide variety of disorders. Understanding of the functional anatomy and pathomechanics of the Achilles tendon is essential for diagnosis and adequate therapy. Possible causes for heel pain include paratenonitis, tendinitis, tendinitis with partial rupture, insertional tendinitis, subachilles and retroachilles bursitis, Haglunds deformity and calcaneal spur. These chronic overuse symptoms may be triggered by pes plano valgus, lateral ankle instability, hyperlaxity, malalignement of the lower extremity, forefoot or hip disorders. In obese patients the deforming forces on the rear foot position and thereby overuse of the achillis tendon due to the overweight are increased. Lack of training with loss of muscular compensation or forefoot disorders also favor overuse problems. A sudden increase of load in an attempt of loosing weight by unaccustomed exercise, without giving the tissue adequate time for adaptation may lead to the start of the symptoms. Therapy of Achilles tendinitis is preferably conservative, in chronic cases operative therapy depends on the structures involved.

Achilles Tendon↗
PubMed2005

[The emotional sensitivity of elderly people--validation of the Profile of Mood States for people over 60 years].

The German short version of the "Profile of Mood States (POMS)" with 35 items (seven-point response scale; rating related to the past 24 hours) was psychometrically tested in a sample of elderly people of 60 years of age and older (n=690; 57% female). The internal structure of the POMS with four factors (dejection, fatigue, displeasure, vigour) could largely be replicated, even though the first three factors are intercorrelated. Reliability of the scales appears to be very good. The convergent validity of the POMS scales could be proved by correlations with the Beck Depression Inventory and the SF-36. Specific norms are presented for four age groups, men and women and elderly living in Eastern and Western Germany. So it seems appropriate to use the German short version of the POMS as a valid and economic instrument for gerontological studies.

Aged↗
PubMed2005

Unusual mass in the hepatic portal of an 86-year-old woman.

Varicose veins in the hepatoduodenal ligament and hepatic portal are normally due to cavernous transformation of the portal vein. We present an unusual case of varices of the common bile duct in an asymptomatic 86-year-old woman who was referred to our hospital for evaluation of a suspected cholangiocarcinoma. A cholangiocarcinoma could be excluded, however, and the diagnosis of intramural varicosis of the common bile duct was made with transabdominal colour Doppler sonography. Sonography showed multiple dilated vessels in the wall of the common bile duct. Most patients with choledochal varices are asymptomatic. Choledochal varices may, however, result in dilatation of the biliary system, causing raised levels of serum alkaline phosphatase and even jaundice.

Aged↗
PubMed2004

[Religiosity and spirituality in the elderly].

The present paper presents results regarding religious attitudes and behaviors as well as the perceived social support by religious communities in n = 593 elderly over 60 years (31.2% female, mean age 69.5 years) from the German general population. The results are based on the German 15-item version SBI-15R-D of the "Systems of Belief Inventory" (Holland et al., 1998). Furthermore, religiosity was analyzed as a potential protective factor regarding body complaints in the elderly. Higher scores on religiosity could be found in women compared to men and in elderly from Western Germany compared to those from Eastern Germany. There were no significant correlations between religiosity and body complaints. It is discussed whether the self-ratings of religiosity reflect conventional ideas of a religious orientated person rather than a genuine spiritual attitude.

Activities of Daily Living↗
PubMed2003

Post-tonsillectomy haemorrhage: a 7-year retrospective study.

Amongst fears about iatrogenic transmission of new variant Creutzfeldt-Jakob disease (vCJD), last year the Department of Health of the U.K. advised that all adenotonsillectomies be performed using disposable instruments. Following implementation of these guidelines, many consultants reported an increase in post-tonsillectomy haemorrhage in association with the use of disposable instruments. We have undertaken a retrospective study of tonsillectomy and have confirmed a significant increase in the incidence of return to the theatre for arrest of postoperative haemorrhage (5.32% vs. 2.18%) during the period when disposable instruments were used.

Creutzfeldt-Jakob Syndrome↗
PubMed2003

[The influence of socio-demographic factors on personality dimensions in the elderly].

The personality factors neuroticism, extraversion, openness for experiences, agreeableness and conscientiousness were investigated in a random population sample of n=497 people over 60 years old with the help of a German version of the NEO Five-Factor Inventory - NEO-FFI (2, 6). The results were compared with those from n=497 people between 18 and 30 years old and with those from n=1051 people between 31 and 60 years old. The elderly described themselves as being less extroverted, less open, more agreeable and more conscientious than the people under 60 years old. Means of the personality factors were not associated with age in the over 60 years old. The average level of neuroticism and conscientiousness was significantly higher in women over 60 years old than in men. People living in the former Eastern Germany were more open and conscientiousness than those living in former Western Germany. A higher level of openness was found in people with a higher educational level. There was a higher level of neuroticism in people living without a partner than in those living with a partner.

Adult↗
PubMed2003

[Somatoform complaints in elderly of Germany].

The aim of this paper is to report on the prevalence of somatoform disorders in older age. A total of 630 representatively selected persons older than 60 years were asked to complete the questionnaire SOMS 2 (Screening for somatoform disorders, Rief et al., 1997). The results show that somatoform pain is very common in old age. Of the people, 71.8% report at least one symptom, 50.5% on at least four symptoms and 23.4% suffer from at least eight symptoms. The frequency of somatoform symptoms is much higher in people over 60 years old than in persons who are younger than 60 years old. Pain is very often localized in several body regions. In contrast to findings from younger age groups, older women do not report more somatoform pain than older men. When looking at the differences between "young olds" and "old olds" somatoform pain increases with increasing age. The high frequency of somatoform pain in older people is in clear contrast to the low prevalences of somatoform disorders defined according to DSM-IV or ICD-10 (0%-0.3%). The results show that the real prevalence of somatoform disorders is extremely underestimated because of the restrictive criteria of the diagnosis systems.

Age Factors↗
PubMed2001

A natural variability in the proline-rich motif of Nef modulates HIV-1 replication in primary T cells.

In the infected host, the Nef protein of HIV/SIV is required for high viral loads and thus disease progression. Recent evidence indicates that Nef enhances replication in the T cell compartment after the virus is transmitted from dendritic cells (DC). The underlying mechanism, however, is not clear. Here, we report that a natural variability in the proline-rich motif (R71T) profoundly modulated Nef-stimulated viral replication in primary T cells of immature dendritic cell/T cell cocultures. Whereas both Nef variants (R/T-Nef) downregulated CD4, only the isoform supporting viral replication (R-Nef) efficiently interacted with signaling molecules of the T cell receptor (TCR) environment and stimulated cellular activation. Structural analysis suggested that the R to T conversion induces conformational changes, altering the flexibility of the loop containing the PxxP motif and hence its ability to bind cellular partners. Our report suggests that functionally and conformationally distinct Nef isoforms modulate HIV replication on the interaction level with the TCR-signaling environment once the virus enters the T cell compartment.

Amino Acid Motifs↗
PubMed2001

Domain assembly, surface accessibility and sequence conservation in full length HIV-1 Nef.

The accessory Nef protein from human and simian immunodeficiency viruses is critical for efficient viral replication and pathogenesis. Here we present an assembly of the full length structure of HIV-1 Nef, allele NL4-3, based on the previously solved anchor and core domain structures. The center part of the 33 residue encompassing flexible loop at the C-terminus of Nef, involved in Nef internalization and CD4 endocytosis, has been modelled. The degree of sequence conservation in HIV-1 Nef proteins was determined using a total of 186 different strains from five different subtypes. The sequence conservation has been correlated with the accessible surface area and with secondary structure features for individual residues. The high amount of flexible regions in Nef accounts for the large surface and the multiple interaction sites the protein exhibits.

Alleles↗
PubMed2001

The Rev/Rex homolog HERV-K cORF multimerizes via a C-terminal domain.

Expression of human endogenous retrovirus K (HERV-K) is associated with germ-cell neoplasia. HERV-K encodes a protein of the Rev/Rex family, cORF, that supports cellular transformation and binds the promyelocytic leukemia zinc finger (PLZF) protein implicated in spermatogenesis. Rev/Rex function invariably depends on multimerization. Here we show that cORF likewise self-associates to form higher-order oligomers. Amino acids (aa) 47-87 in cORF are sufficient, aa 75-87 essential for self-association. Consistently, this domain is predicted to form a hydrophobic alpha-helix that may represent an oligomerization interface. The existence of a dimerization-competent cORF mutant lacking PLZF-binding activity (cORF47-87) suggests a way of dominant negative inhibition of the proposed tumor susceptibility factor cORF.

Dimerization↗
PubMed2001

[Psychiatric problems in the elderly--standardization of the Symptom Check List SCL-90-R in patients over 60 years of age].

In the following article, data of the symptom checklist SCL-90-R (Derogatis 1986) for elderly people are introduced, including an estimation of the controlling factors on psychological complaints in old age. The representative sample is based on 394 persons aged 61 to 96; their psychological complaints have been studied with respect to SCL-90-R. Evidently elderly people did not state an increasing load on psychological complaints, but a different structure of psychological symptoms. Therefore with increasing age the scales "Somatization", "Obsessive-compulsive" and "Phobic anxiety" increase, while "Interpersonal sensitivity", "Anger--hostility" and "Paranoid ideation" are decreasing. Within that frame, elderly females report increasing symptomatic load compared to elderly males. Furthermore, aspects of social support and health-related attitudes were found to be important predictors of psychological complaints in old age.

Aged↗
PubMed2001

Solution NMR structure of the cold-shock protein from the hyperthermophilic bacterium Thermotoga maritima.

Cold-shock proteins (Csps) are a subgroup of the cold-induced proteins preferentially expressed in bacteria and other organisms on reduction of the growth temperature below the physiological temperature. They are related to the cold-shock domain found in eukaryotes and are some of the most conserved proteins known. Their exact function is still not known, but translational regulation, possibly via RNA chaperoning, has been discussed. Here we present the structure of a hyperthermophilic member of the Csp family. The NMR solution structure of TmCsp from Thermotoga maritima, the hyperthermophilic member of this class of proteins, was solved on the basis of 1015 conformational constraints. It contains five beta strands combined in two antiparallel beta sheets making up a beta barrel structure, in which beta strands 1-4 are arranged in a Greek-key topology. The side chain of R2, which is exclusively found in thermophilic members of the Csp family, probably participates in a peripheral ion cluster involving residues D20, R2, E47 and K63, suggesting that the thermostability of TmCsp is based on the peripheral ion cluster around the side chain of R2.

Amino Acid Sequence↗