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Biomedical subjects

G Meyer

Publications and source records attributed to G Meyer.

At least 37 records · Page 2Linked to original sources
PubMed2005

Thermo-chemotherapy for intermediate or high-risk recurrent superficial bladder cancer patients.

BACKGROUND: The purpose of this study was to evaluate the efficacy of combined local hyperthermia and intravesical mitomycin-C (MMC) in a selected group of patients with intermediate or high-risk recurrent transitional cell carcinoma (TCC) of bladder. PATIENTS AND METHODS: Forty-seven patients with multiple or recurrent Ta or T1 TCC of the bladder were treated with intravesical MMC and local hyperthermia of the bladder wall. Patients were treated with either a prophylactic protocol (40 mg MMC) after complete transurethral resection of all tumours or with an ablative protocol (80 mg MMC) in patients with viable tumours. RESULTS: Thirty-two patients were eligible for analysis. The prophylactic protocol was administered to 22 patients. After a mean follow-up of 289 days, 20 patients (91%) were recurrence free. Two patients (9%) had tumour recurrence after a mean period of 431 days. The ablative protocol was administered to 10 patients. Complete tumour ablation was achieved in eight patients (80%) after a mean follow up of 104.5 days. CONCLUSIONS: Our efficacy and safety results confirm those reported in previously published studies, suggesting the promising value of this combined treatment modality for both prophylactic and ablative patients. The ablative protocol offers an alternative therapy for a selected patient population for whom no other treatment option exists.

Adult↗
PubMed2005

Cofilin activity during insulin-like growth factor I-stimulated neuroblastoma cell motility.

Insulin-like growth factor I (IGF-I) is a potent stimulator of neuroblastoma cell motility. Cell motility requires lamellipodium extension at the leading edge of the cell through organized actin polymerization, and IGF-I stimulates lamellipodial elaboration in human neuroblastoma cells. Rac is a Rho GTPase that stimulates lamellipodial formation via the regulation of actin polymerization. In this study, we show that IGF-I-stimulated phosphatidylinositol 3-kinase (PI-3K) activity promotes rac activation and subsequent activation of the down- stream effectors LIM kinase and cofilin. Overexpression of wild-type LIM kinase and wild-type Xenopus ADF/cofilin (XAC) suppresses IGF-I-stimulated motility in SH-SY5Y cells, while expression of dominant negative LIM kinase and constitutively active XAC increases SH-SY5Y motility in the absence of IGF-I stimulation. These results suggest that regulation by cofilin of actin depolymerization is important in the process of neuroblastoma cell motility, and IGF-I regulates cofilin activity in part through PI-3K, rac, and LIM kinase.

Actin Depolymerizing Factors↗
PubMed2005

Microbiological evaluation of two hand hygiene procedures achieved by healthcare workers during routine patient care: a randomized study.

The aim of this study was to evaluate the comparative microbiological efficacy of hand rubbing and handwashing in healthcare workers from different wards, with particular emphasis on transient flora, and to assess predisposing factors for hand contamination after patient care in everyday practice. Over a six-month period, 50 healthcare workers were randomly assigned, using a crossover design, to perform handwashing with unmedicated soap and hand rubbing with an alcoholic solution following a healthcare procedure. Imprints of palms and fingertips were taken separately before and after each hand hygiene procedure. The number of colonies per plate was counted and transient pathogens were identified. Risk factors for hand contamination were determined. Hand rubbing produced a significantly greater reduction in microbiological load than handwashing (P<0.0001 for palms and P=0.0003 for fingertips). In multivariate analysis, working in a medical ward rather than in an intensive care unit was significantly associated with increased hand contamination (P=0.03 for palms and P=0.02 for fingertips). Transient pathogens were found on 15% of healthcare workers' hands before hand hygiene. The only factor associated with hand contamination by transient pathogens was the absence of gloving during the healthcare procedure (odds ratio 4.8; 95% confidence interval 1.2-19; P=0.03). After hand rubbing, no transient pathogens were recovered, while these were found in two cases after handwashing. Hand rubbing is more efficacious than handwashing for the decontamination of healthcare workers' hands following contact with patients and patients' environments. Gloving may reduce microbiological hand contamination by transient pathogens.

2-Propanol↗
PubMed2005

How safe are laparoscopic intracorporeal anastomoses?

BACKGROUND: A recent German Multicenter Study comprising 3 070 laparoscopic colorectal resections indicates that complete intracorporeal anastomoses are performed in only 1.8 % cases. The aim of our study was to review and analyse the safety of complete intracorpeal anastomosis. METHODS: In a literature survey we searched for complete intracorporeal anastomosis with different key words. RESULTS: In agreement with the literature, technically demanding hand-sutured anastomoses are no common practice. Intracorporeal anastomosis is usually done using endoscopic linear stapling devices or a conventional circular stapler by performing end-to-end, end-to-side, and side-to-side anastomoses. These techniques are more frequently used in the upper than in the lower gastrointestinal tract. CONCLUSIONS: The data published so far, however, indicates that completely intracorporeal performed anastomoses are safe in the hands of laparoscopically experienced surgeons. This technique implies very low percentages of postoperative stenoses (0-10 %) and, furthermore, very low percentages of postoperative anastomotic leakages (0-8 %).

Anastomosis, Surgical↗
PubMed2005

Differential value of risk factors and clinical signs for diagnosing pulmonary embolism according to age.

INTRODUCTION: The diagnostic value of clinical presentation of pulmonary embolism (PE) is uncertain in the elderly, who often have concomitant cardiopulmonary diseases that may mimic PE. The aim of our study was to assess the differential value of risk factors, symptoms and clinical signs of venous thromboembolism, results of electrocardiogram and chest X-ray for the diagnosis of PE in suspected patients according to age. METHODS: We analyzed data from two outcome studies which enrolled 1721 consecutive patients presenting in the emergency department with clinically suspected PE defined as acute onset of new or worsening shortness of breath or chest pain without any other obvious etiology. All patients underwent a sequential diagnostic work-up and a 3-month follow-up. RESULTS: The proportion of confirmed PE was 24.2% (416 of 1721). Strength of the association with PE did not differ according to age group for history of venous thromboembolism (VTE), recent surgery, tachypnea at admission or right ventricular strain on electrocardiogram. Active malignancy, hemoptysis, tachycardia, hemidiaphragmatic elevation and pleural effusion at chest X-ray were no more associated with PE in the patients aged of 75 years or more. Finally, symptoms and signs of deep venous thrombosis, and an alternative diagnosis less probable than PE were associated with PE in all age groups, but the strength of this association decreased significantly with advancing age. CONCLUSION: Some risk factors, symptoms and signs of VTE are less strongly or even not at all associated with PE in the elderly. Physicians should take this into account when attending elderly patients suspected of PE and when assessing their clinical probability of PE.

Age Factors↗
PubMed2005

German dental faculty attitudes towards computer-assisted learning and their correlation with personal and professional profiles.

BACKGROUND: Compared with its potential, computer technology use is still lacking in medical/dental education. OBJECTIVES: To investigate the primary advantages of computer-assisted learning (CAL) systems in German dental education, as well as the reasons for their relatively low degree of use correlated with personal and professional profiles of respondents. METHOD: A questionnaire was mailed to heads in the departments of conservative dentistry and prosthetic dentistry in all dental schools in Germany. Besides investigating the advantages and barriers to the use of computer technology, the questionnaire also contained questions regarding each respondent's gender, age, academic rank, experience in academia and computer skills. RESULTS: The response rate to the questionnaire was 90% (112 of 125). The results indicated a distinct discrepancy between the desire for and actual occurrence of lectures, seminars, etc. to instruct students in ways to search for and acquire knowledge, especially using computer technology. The highest-ranked advantages of CAL systems in order, as seen by respondents, were the possibilities for individual learning, increased motivation, and both objective theoretical tests and practical tests. The highest-ranked reasons for the low degree of usage of CAL systems in order were the inability to finance, followed equally by a lack of studies of CAL and poor cost-advantage ratio, and too much effort required to integrate CAL into the curriculum. Moreover, the higher the computer skills of the respondents, the more they noted insufficient quality of CAL systems (r = 0.200, P = 0.035) and content differences from their own dental faculty's expert opinions (r = 0.228, P = 0.016) as reasons for low use. CONCLUSION: The correlations of the attitudes towards CAL with the personal and professional profiles showed not only statistical significant reinforcements of, but also interesting deviations from, the average responses.

Adult↗
PubMed2005

Ion transport across the gallbladder epithelium.

The function of the gallbladder is not only to store bile, but also to concentrate it during the interdigestive phase by means of salt-dependent water reabsorption. On the contrary, secretions of water and salt take place during the digestive phase. Dysregulation of ion absorption or secretion are common in many gallbladder diseases, such as colelithiasis. Transepithelial absorptions are determined by the Na+/K+ pump on the basolateral membrane, and by several apical membrane Na(+)-coupled transporters. Among these, some isoforms of Na+/H+ and Cl-/HCO3(-) exchangers have been studied. The presence of a Na(+)-Cl(-) simport has been molecularly and functionally characterized in some animal species. The ion transepithelial secretion is mainly dependent on an apical chloride transport attributable to a CFTR-like cAMP-activated channel with high permeability to HCO3(-). The apical membrane electrical potential is one of the factors influencing anion secretion and is maintained by the activity of cAMP-dependent K+ channels. The regulation of the activity of these channels is complex, because of their sensitivity to voltage, and to intracellular calcium and pH. The coordinated interplay underlying the regulation of transporters and channels needs to be clarified yet, as well as the interactions between transporters, channels and aquaporins.

Animals↗
PubMed2004

Validation of a quality of life questionnaire measuring the subjective fear of falling in nursing home residents.

A quality of life scale was developed to measure the subjective fear of falling in nursing home residents. We assessed the dimensions fear of falling, daily living and social life within a randomized controlled trial of hip protector use. The Nottingham Health Profile (NHP) was used for validation. Statistical analysis covered factor analysis, internal consistency of subscales, construct and discriminant validity. Factor analysis revealed three reliable components (Cronbach's Alpha): fear of falling (0.92), social restriction due to limited mobility (0.74) and restriction by clothes due to the hip protector (0.72). The subscales fear of falling and social restriction were significantly intercorrelated with all subscales of the NHP. The new tool is a reliable and valid measure of fear of falling in nursing home residents. However, generalizability and applicability are limited by the small proportion of subjects able to complete the tests.

Accidental Falls↗
PubMed2004

Laparoscopic diaphragmatic plication: long-term results of a novel surgical technique for postoperative phrenic nerve palsy.

BACKGROUND: Paralysis of the diaphragm is a severe complication of cardiothoracic surgery carrying significant morbidity and mortality. This study demonstrates a novel minimally invasive technique for treatment of phrenic nerve injuries presenting with symptomatic eventration of the diaphragm. It also presents long-term results of three patients treated with this operation. METHODS: Chest x-ray proved eventration of the left diaphragm in all patients. Two patients required treatment due to prolonged respirator therapy/assisted ventilation for 4 weeks after cardiac surgery. One patient suffered from progressive dyspnea caused by increasing left-sided diaphragmatic elevation and underwent surgery 2 years after cardiac surgery. In all cases, a minimally invasive abdominal approach was chosen. During surgery the dome of the diaphragm was pulled down via three percutaneously inserted retention stitches. This resulted in two or three folds of the diaphragm located within the abdomen. These diaphragmatic folds were subsequently tightened using 12 to 15 unresorbable sutures with extracorporally prepared knots. Surgical as well as long-term follow-up results are presented of all patients and a review of the current literature is provided. RESULTS: Mean operating time was 203 min; mean intraoperative blood loss was 130 ml. No major complications occurred during surgery or the postoperative period. At a median follow-up of 72 months no recurrence was observed. CONCLUSIONS: Laparoscopic diaphragmatic plication provides excellent relief of symptoms caused by diaphragmatic paralysis. There is no perioperative morbidity, and hospital stay is short. The laparoscopic approach, therefore, is an attractive surgical alternative for the treatment of phrenic nerve palsy and should be considered in all suitable patients.

Aged↗
PubMed2004

Signs of temporomandibular disorders in tinnitus patients and in a population-based group of volunteers: results of the Study of Health in Pomerania.

The literature has documented a controversial discussion on the possible relationship of otogenous symptoms and craniomandibular dysfunction since the 1920s. Therefore, an investigation was conducted which consisted of two parts: a case study with population-based controls and a cross-sectional study. The aim of the first study was to screen a group of patients suffering from acute or chronic tinnitus for temporomandibular disorders (TMD) in comparison with a population-based group of volunteers without tinnitus. To this end, 30 patients (13 females and 17 males, age 18-71 years) suffering from acute hearing loss associated with tinnitus, isolated acute tinnitus, and chronically transient tinnitus were examined for symptoms of craniomandibular dysfunction. The results were compared with those of clinical functional analysis from 1907 subjects selected representatively and according to age distribution from the epidemiological 'Study of Health in Pomerania' (SHIP); the occurrence of tinnitus was ruled out in these control subjects. Statistical analysis was performed with Chi-square and Mann-Whitney U-tests. Sixty per cent of the tinnitus patients and 36.5% of the control subjects exhibited more than two symptoms of TMD (P = 0.004). Tinnitus patients had significantly more muscle palpation pain (P < 0.001), temporomandibular joint (TMJ) palpation pain (P < 0.001), and pain upon mouth opening (P < 0.001) than the general population group. No statistical differences were found in TMJ sounds, limitation of mandibular movement, or hypermobility of the TMJ. Furthermore, 4228 subjects of the population group examined in the epidemiological study were screened for co-factors of tinnitus with the help of a multivariate logistic regression model which was adjusted for gender, age, and a variety of anamnestic and examined data. Increased odds ratios (OR) were found for tenderness of the masticatory muscles (OR = 1.6 for one to three painful muscles and OR = 2.53 for four or more painful muscles), TMJ tenderness to dorsal cranial compression (OR = 2.99), listlessness (OR = 2.0) and frequent headache (OR = 1.84) A relationship between tinnitus and TMD was established in both examinations. Tinnitus patients seem to suffer especially from myofascial and TMJ pain. A screening for TMD should be included in the diagnostic survey for tinnitus patients.

Acute Disease↗
PubMed2004

Deposition of Foradil P in human lungs: comparison of in vitro and in vivo data.

In order to characterize the efficacy of dry powder inhalers, in vitro measurements are much easier to perform than human deposition studies, especially in early stages of drug development. In this study, lung deposition and delivered dose of radiolabeled Foradil P inhaled with the Aerolizer were measured in 10 healthy subjects. These data were then compared with data derived from an in vitro assessment of the device output and particle size distribution combined with mathematical modeling of lung deposition (modified ICRP-model). Delivered dose and lung deposition increased slightly but statistically significant with the inhalation peak flow in both the in vivo data and the in vitro data. The delivered dose ranged from 60% to 80% and lung deposition, relative to the fill weight, from 13% to 28%. Differences between the in vitro and in vivo data were slight and statistically not significant. This study indicates that in vitro assessment of device performance, in combination with lung deposition delivery data, are in good agreement with deposition data measured in healthy subjects. Since there was only a slight flow rate dependency of lung deposition without clinical relevance, it may additionally be concluded that the Aerolizer is a robust, easy to handle inhalation device with stable and reproducible drug delivery characteristics.

Administration, Inhalation↗
PubMed2004

Reelin receptors in developing laminated brain structures of mouse and human.

Reelin is an extracellular matrix protein secreted by a variety of cell types throughout the developing brain. The target cells for reelin express the cytoplasmic adapter protein Dab1, which binds to the reelin receptors VLDLR and ApoER2. In the present work, we have studied the localization of both receptors in developing mouse and human cortex, olfactory bulb and cerebellum. In mouse, some Cajal-Retzius cells express reelin and VLDLR; in humans, all the components of the signalling pathway (Reelin, Dab1, VLDLR and ApoER2) are present in subsets of Cajal-Retzius cells. In the mouse cortical plate, VLDLR and ApoER2 are present from E15 to postnatal stages; in human cortical plate they are most prominent at approximately 20 gestational weeks. In mice, cerebellar Purkinje cells only express VLDLR whereas in humans they express both VLDLR and ApoER2. Mitral cells of the mouse olfactory bulb are ApoER2-positive and VLDLR-negative. In sum, the receptor expression patterns are similar in the human and mouse cortical plate but differ in Cajal-Retzius and Purkinje cells, which in humans express additional components of the reelin-Dab1 pathway.

Adaptor Proteins, Signal Transducing↗
PubMed2004

DentSim - a future teaching option for dentists.

Apart from a requirement to acquire more and more academic knowledge, during their training, dental students need to acquire a full range of highly precise manual and technical skills, including excellent hand/eye coordination, to enable them to visualize and understand how to prepare cavities, prior to placing restorations. Furthermore, unlike medical students, dental students are in the position of administering treatment to patients very early in their training. The increasing academic workload means that these skills have to be mastered in a short space of time. This you will gain in the future only through the use of effective methods of the educations - for example by the use of the computer-assisted dental simulators (DentSim/DenX), which serves the visual-, audio- and practical learning channel simultaneously. Unlike the conventional phantom heads, the DentSim-unit has the following advantages - the acquisition of knowledge takes place in a multimedia learning environment with a high audio-visual content and degree of interaction and complexity, - problem-oriented learning takes place through clinically relevant work, - individual students can work to personalized programs through the digital tutor function, - two-dimensional knowledge is transferred into three-dimensional spatial work, - three-dimensional preparations can be easily analysed by two-dimensional error analysis, - all preparation exercises are recorded for error and effectiveness analysis. Apart from student training, the computer-assisted simulators can also be used for the evaluation of the effectiveness or the quality control of various teaching methods in the context of Evidence Based Dental Education.

Computer Simulation↗
PubMed2003

Reelin expression during embryonic brain development in Crocodylus niloticus.

The expression of reelin mRNA and protein was studied during embryonic brain development in the Nile crocodile Crocodylus niloticus, using in situ hybridization and immunohistochemistry. In the forebrain, reelin was highly expressed in the olfactory bulb, septal nuclei, and subpial neurons in the marginal zone of the cerebral cortex, dorsal ventricular ridge, and basal forebrain. At early stages, reelin mRNA was also detected in subventricular zones. In the diencephalon, the ventral lateral geniculate nuclei and reticular nuclei were strongly positive, with moderate expression in the habenula and focal expression in the hypothalamus. High expression levels were noted in the retina, the tectum, and the external granule cell layer of the cerebellum. In the brainstem, there was a high level of signal in cochleovestibular, sensory trigeminal, and some reticular nuclei. No expression was observed in the cortical plate or Purkinje cells. Comparison with reelin expression during brain development in mammals, birds, turtles, and lizards reveals evolutionarily conserved, homologous features that presumably define the expression profile in stem amniotes. The crocodilian cortex contains subpial reelin-positive cells that are also p73 positive, suggesting that they are homologous to mammalian Cajal-Retzius cells, although they express the reelin gene less intensely. Furthermore, the crocodilian cortex does not contain the subcortical reelin-positive cells that are typical of lizards but expresses reelin in subventricular zones at early stages. These observations confirm that reelin is prominently expressed in many structures of the embryonic brain in all amniotes and further emphasize the unique amplification of reelin expression in mammalian Cajal-Retzius cells and its putative role in the evolution of the cerebral cortex.

Alligators and Crocodiles↗
PubMed2003

Magneto-optical near-field microscopy of ultrathin films in ultrahigh vacuum.

We demonstrate that magnetic domains of ultrathin films can be imaged in situ in ultrahigh vacuum (UHV) by scanning near-field optical microscopy in combination with a Sagnac interferometer (Sagnac-SNOM). In the present set-up, the Sagnac interferometer is not only used for measuring the magneto-optical Kerr effect but also for tip-to-sample distance control. The high sensitivity of the instrument enabled us to study the magnetization reversal processes in externally applied magnetic fields in ultrathin films of Fe and Ni grown on Cu(100) single crystals.

Journal Article↗