Biomedical subjects

A Meyer

Publications and source records attributed to A Meyer.

At least 19 recordsLinked to original sources

PubMed2006

State of the art management of adrenal masses--"how to do it?".

By the frequent use of computed tomography or ultrasound the detection of incidentally found adrenal tumours has become a common problem. This is also reflected in the worldwide proliferation of literature over the past decades. Most incidentally-found adrenal tumours are benign non-functioning cortical adenomas. But benign functioning tumours producing aldosterone, cortisol or catecholamines, adrenocortical carcinoma or adrenal gland metastasis can also be found. Surgical therapy is always indicated in case of hormonal overproduction or in case of suspected adrenocortical carcinoma; in all other cases the correct and adequate therapeutic approach is still under debate and a controversial topic of discussion. This review deals with the different forms of adrenal tumours regarding the optimal diagnostic and therapeutic approach to give physicians an easy-to-follow guideline.

Adrenal Gland Neoplasms↗

PubMed2006

Effect of densification on the density of vibrational states of glasses.

We studied the effect of densification on the vibrational dynamics of a Na(2)FeSi(3)O(8) glass. The density of vibrational states (DOS) has been measured using nuclear inelastic scattering. The corresponding changes in the microscopic, intermediate-range, and macroscopic properties have also been investigated. The results reveal that, in the absence of local structure transformations, the Debye level and the glass-specific excess of vibrational states above it have the same dependence on density, and the evolution of the DOS is fully described by the transformation of the elastic medium.

Journal Article↗

PubMed2006

Which complement assays and typings are necessary for the diagnosis of complement deficiency in patients with lupus erythematosus? A study of 25 patients.

INTRODUCTION: Deficiencies in components of the classical pathway of complement activation are strong risk factors for lupus erythematosus (LE).Yet, it has not been addressed whether the conventional measurements of the serum hemolytic CH50 activity and antigenic concentrations of C3 and C4 are sufficient to asses a deficiency in C4A, C4B or C2 components, the most common deficiencies associated with LE. PATIENTS AND METHODS: In a retrospective series, we performed complement analyses in 35 patients with LE who were systematically screened for a complement deficiency. The majority of patients had cutaneous LE with mild systemic involvement and no complement consumption. Of 25 patients (72%) with complement deficiency we found 13 with a partial C4A deficiency, 2 with a complete C4A deficiency, 6 with a partial C4B deficiency, 2 with a complete C4B deficiency and 2 with a combined partial C2 and C4A deficiency. RESULTS: The total complement activity (CH50) was decreased in only one out of two patients with complete C4B deficiency. CH50 level was found to be low-normal (35-38 U/ml(-1)) in one patient with partial C4B deficiency, one patient with complete C4B deficiency and both patients with combined partial C4A and C2 deficiency. Total C4 levels were normal in 9 out of 13 the patients with a partial C4A deficiency and in 2 out of 6 patients with a complete C4B deficiency. The antigenic concentration of C3 was low in only 1 patients with a complete C4B deficiency and within the normal range in all the others patients. Overall, 50% of the patients had normal or elevated C3, C4, and CH50 levels. DISCUSSION: This study emphasizes that the usual measurements of CH50, C3 and C4 levels are not adequate to detect a C4 and/or C2 deficiency in patients with LE. In epidemiologic or investigative studies addressing the prevalence of complement deficiency, more elaborated diagnostic tests, such as C4 protein allotyping, C2 level measurement and genetic screening for type I C2 deficiency should also be performed.

Adult↗

PubMed2006

Benign giant cell tumor of the spine: an unusual indication for radiotherapy.

INTRODUCTION: Giant cell tumors are rare primary bone tumors. Multicentricity as well as spinal localization is extremely rare. CASE REPORT: We report about a 64-year-old female patient presenting with history of three osseous and one pulmonal manifestation of a benign giant cell tumor that have manifested metachronously within 23 years. The two periphery bone and the one pulmonal manifestation were treated surgically with success. Now, a further osseous lesion occurred at the seventh vertebra of the thoracic spine and was treated by dorsal instrumentation and replacement of the seventh vertebra. Nine months later, local recurrence of this benign giant cell tumor developed at the thoracic spine and was treated with radiotherapy with a total dose of 45 Gy. Three months after salvage radiotherapy definite local progress occurred localized within the former radiation treatment field. Due to neurological deficits a laminectomy and a stabilization of the destroyed sixth vertebra with bone cement was carried out. Histopathological examination again showed benign giant cell tumor without suspicion of malignancy. CONCLUSION: In the literature the use of radiation therapy remains an appropriate therapy option in benign giant cell tumors with minimal adverse sequelae if primary surgical treatment is not feasible or fails. In cases of definitive radiotherapy a total dose > 45 Gy should be discussed.

Female↗

PubMed2006

Magnetic versus manual guidewire manipulation in neuroradiology: in vitro results.

INTRODUCTION: Standard microguidewires used in interventional neuroradiology have a predefined shape of the tip that cannot be changed while the guidewire is in the vessel. We evaluated a novel magnetic navigation system (MNS) that generates a magnetic field to control the deflection of a microguidewire that can be used to reshape the guidewire tip in vivo without removing the wire from the body, thereby potentially facilitating navigation along tortuous paths or multiple acute curves. METHOD: The MNS consists of two permanent magnets positioned on either side of the fluoroscopy table that create a constant precisely controlled magnetic field in the defined region of interest. This field enables omnidirectional rotation of a 0.014-inch magnetic microguidewire (MG). Speed of navigation, accuracy in a tortuous vessel anatomy and the potential for navigating into in vitro aneurysms were tested by four investigators with differing experience in neurointervention and compared to navigation with a standard, manually controlled microguidewire (SG). RESULTS: Navigation using MG was faster (P=0.0056) and more accurate (0.2 mistakes per trial vs. 2.6 mistakes per trial) only in less-experienced investigators. There were no statistically significant differences between the MG and the SG in the hands of experienced investigators. One aneurysm with an acute angulation from the carrier vessel could be navigated only with the MG while the SG failed, even after multiple reshaping manoeuvres. CONCLUSION: Our findings suggest that magnetic navigation seems to be easier, more accurate and faster in the hands of less-experienced investigators. We consider that the features of the MNS may improve the efficacy and safety of challenging neurointerventional procedures.

Catheterization↗

PubMed2006

The first Belgian hand transplantation--37 month term results.

The first Belgian hand transplant was a 22 year-old man with a traumatic amputation of his dominant hand at the junction of the middle and distal thirds of the forearm. The donor and recipient had three HLA mismatches. The cross-match was negative. The total ischaemic time was slightly over 6 hours. Immunosuppression included antithymocyte globulins at induction and tacrolimus, mycophenolate mofetil and prednisolone as induction and maintenance therapy. There has been no episode of rejection. The only significant complications, except for transient hyperglycaemia, were psychological. At 37 months post-transplantation, the patient has fully incorporated his transplant into his self-image and is back at work. He has good sensibility (two-point discrimination of 6mm at the thumb and index finger pulps), acceptable wrist and finger motion with functioning intrinsic muscles. According to Chen's criteria, the result is good to excellent.

Adult↗

PubMed2006

Reconstruction of defects in the head and neck with free flaps: 20 years experience.

Between March 1982 and December 2002 we did a total of 534 reconstructions with free flaps from various donor sites for 529 patients. The jejunum was the donor site in 181 reconstructions (34%), followed by the radial forearm flap in 173 reconstructions (32%); 86% of the reconstructions were immediately after excisions. Surgical re-exploration was necessary in 37 patients (7%); the failure rate from necrosis of the flap was 5%. Factors associated with complications were American Society of Anesthesiology (ASA) class and age.

Adolescent↗

PubMed2006

[Diagnosis and therapy of auditory synaptopathy/neuropathy].

Pathological auditory brainstem responses (lack of responses, elevated thresholds and perturbed waveforms) in combination with present otoacoustic emissions are typical audiometric findings in patients with a hearing impairment that particularly affects speech comprehension or complete deafness. This heterogenous group of disorders first described as "auditory neuropathy" includes dysfunction of peripheral synaptic coding of sound by inner hair cells (synaptopathy) and/or of the generation and propagation of action potentials in the auditory nerve (neuropathy). This joint statement provides prevailing background information as well as recommendations on diagnosis and treatment. The statement focuses on the handling in the german language area but also refers to current international statements.

Brain Stem↗

PubMed2006

[Intraocular pressure measurements with the Proview self-tonometer in comparison of Goldmann applanation tonometry in healthy and glaucomatous eyes].

BACKGROUND: The aim of this study was to compare the results of intraocular pressure (IOP) measurements obtained using the pressure phosphene tonometer Proview with those from Goldmann applanation tonometer (GAT) in normal and glaucomatous eyes. PATIENTS AND METHODS: The IOP in 150 eyes of 62 healthy volunteers and 88 patients with glaucoma or ocular hypertension was measured prospectively in a sitting position. After being trained to use the Proview device, Goldmann applanation tonometry was performed first. Then the patient took a reading with the Proview self-tonometer. RESULTS: For all investigated eyes the measurements with the Proview were on average 5.5 mmHg higher than those by GAT. Only 34 % of the readings from the two devices were within a difference range of +/- 3 mmHg. On comparing the group of glaucomatous patients with slight visual field defects with the group of healthy subjects and patients with ocular hypertension without visual field defects we determined almost the same mean difference between the Proview and GAT (mean difference in the group with visual field defects = 4.7 +/- 4.1 mmHg; without defects = 4.8 +/- 2.9 mmHg). CONCLUSIONS: The tonometer Proview did not show a close agreement to GAT. Therefore, the PPT does not offer an alternative method for measuring IOP. We do not recommend the Proview for self-tonometry at home or for clinical management of patients with glaucoma. Slight visual field defects seem to have no influence on intraocular pressure measurement with the self-tonometer.

Adolescent↗

PubMed2006

Multicriteria decision analysis: a comprehensive decision approach for management of contaminated sediments.

Contaminated sediments and other sites present a difficult challenge for environmental decisionmakers. They are typically slow to recover or attenuate naturally, may involve multiple regulatory agencies and stakeholder groups, and engender multiple toxicological and ecotoxicological risks. While environmental decision-making strategies over the last several decades have evolved into increasingly more sophisticated, information-intensive, and complex approaches, there remains considerable dissatisfaction among business, industry, and the public with existing management strategies. Consequently, contaminated sediments and materials are the subject of intense technology development, such as beneficial reuse or in situ treatment. However, current decision analysis approaches, such as comparative risk assessment, benefit-cost analysis, and life cycle assessment, do not offer a comprehensive approach for incorporating the varied types of information and multiple stakeholder and public views that must typically be brought to bear when new technologies are under consideration. Alternatively, multicriteria decision analysis (MCDA) offers a scientifically sound decision framework for management of contaminated materials or sites where stakeholder participation is of crucial concern and criteria such as economics, environmental impacts, safety, and risk cannot be easily condensed into simple monetary expressions. This article brings together a multidisciplinary review of existing decision-making approaches at regulatory agencies in the United States and Europe and synthesizes state-of-the-art research in MCDA methods applicable to the assessment of contaminated sediment management technologies. Additionally, it tests an MCDA approach for coupling expert judgment and stakeholder values in a hypothetical contaminated sediments management case study wherein MCDA is used as a tool for testing stakeholder responses to and improving expert assessment of innovative contaminated sediments technologies.

Journal Article↗

PubMed2006

Indications and results of surgery for incidentally found adrenal tumors.

INTRODUCTION: The accidental discovery of an adrenal mass called incidentaloma has become an increasingly frequent clinical problem with the question of a correct and appropriate therapeutic approach being the subject of controversial discussions. MATERIALS AND METHODS: Clinical charts of 52 patients (22 male, 30 female) who underwent adrenalectomy for an incidentaloma at our institution between 1987 and 2001 were reviewed. RESULTS: Median age was 56.4 years. Reasons for surgery were unclear significance in 22 patients, suspicion of malignancy in 5, increase in size in 8, maximum tumor diameter of more than 5 cm in 7, fear of malignancy in 1, and subclinical secretion of cortisol in 5 patients. No data were available for 4 patients. Surgical resection was performed using a conventional transabdominal approach in 28 patients, a conventional dorsal approach in 17 patients, and an endoscopic retroperitoneal approach in 7 patients. Histopathologic examination ruled out adrenal adenoma in 32 patients, adrenal myelolipoma in 12, unilateral nodular hyperplasia in 4, cystic lesion in 3, and adrenocortical carcinoma in 1 patient. The mean size of all lesions was 5.5 cm. Evaluating the criteria for surgical treatment regarding age of the patients and size of the lesions, 25 patients (48%), including the patient with the adrenocortical carcinoma, were younger than 60 years and had an adrenal lesion exceeding 4 cm in size. During postoperative follow-up that was available for 39 patients, 3 developed contralateral tumors that were treated by resection in 1 and by close follow-up in 2. CONCLUSIONS: Size should not be the sole criterion; treatment should be tailored to the individual patient. Especially in patients younger than 60 years with an adrenal lesion exceeding 4 cm in size, an adrenalectomy, predominantly via an endoscopic approach, should be carried out, because a repeated and life-long close follow-up of an anxious patient who has been informed of the diagnosis will in some cases exceed the cost of a single endoscopic operation.

Adrenal Gland Neoplasms↗

PubMed2006

Targeting RGD recognizing integrins: drug development, biomaterial research, tumor imaging and targeting.

Integrins constitute an important class of cell adhesion receptors responsible not only for cell-matrix adhesion but also for signaling bidirectionally across the membrane. Integrins are involved in many biological processes such as angiogenesis, thrombosis, inflammation, osteoporosis and cancer. Integrins thus play a key role in many severe human diseases. In this review we will describe recent research and development of RGD-containing integrin ligands for medical applications including drug design, radiolabeling, drug targeting, as well as biomaterial research. Many ligands have been developed for targeting the avb3 integrin in order to block angiogenesis or osteoporosis, but there are also other integrins like avb5 and a5b1 which become more and more interesting for similar purposes. aIIbb3 constitutes a potent target in thrombosis therapy; but the search for suitable ligands is still ongoing. We will reconstruct the drug development process for these integrin subtypes considering selected examples with focus on structure based design. Different structural requirements are pointed out concerning integrin activity and particularly the selectivity towards the distinct integrin types. Furthermore, we will show recent progress in tumor and thrombosis imaging based on radiolabeled RGD-containing ligands binding avb3 or aIIbb3, respectively. Additionally further advances in biomaterial research are presented. We describe the coating of different implant materials with various avb3 recognizing ligands for the purpose of increasing cell attachment and biocompatibility.

Animals↗

PubMed2006

[Evaluation of the vaccine coverage of the general practitioners in the French Community].

The present inter-University study aims to analyze the vaccine statute of the Belgian French-speaking general practionners and the reasons of their possible non-vaccination. A questionnaire with an exhaustive list of vaccines was sent by postal way to a random sample of thousand two hundred and twenty general practitioners. The results were analyzed via SPSS 13. The rate of answer is 60.83%. Two thirds of the doctors (67%) considered themselves in order of vaccination anti-influenza. A majority of doctors (59.7%) is vaccinated systematically each year. The majority of the doctors (83%) considered themselves in antitetanus order of vaccination. Two thirds (67%) think that the vaccine protects from 5 to 10 years. Nearly 73% of the doctors considered themselves in order of vaccination against hepatitis B. More than 50% of the doctors received a vaccine HBV since less than 10 years. The majority of the doctors (79.2%) made a blood control of their protection after vaccination HBV Almost half of the doctors thinks that the vaccine protect for life, 23% from 10 to 20 years and 14% from 5 to 10 years. Two thirds (67%) of the doctors did not make a vaccine against rubella. In 80% of the cases vaccination dated from more than 20 years. In nearly two thirds of the cases the doctors did not make blood control of their protection. Nearly 60% of the questioned doctors think that vaccination offers a protection to life. About half of the doctors did not consider themselves in order of vaccination against the whooping-cough. In three quarter of the cases last vaccination dated from more than 20 years. The two principal durations of protection of the vaccine are with life and between 10 and 20 years. Three quarters of the questioned doctors are considered in order of vaccination against the poliomyelitis. However in 62% of the cases the last vaccine goes up with more than 20 years. More two thirds of the doctors think than the vaccine protects with life or from 10 to 20 years. Two thirds of doctors considered themselves in order of vaccination against the diphteria. For a third of the doctors the vaccine dated from less than 5 years, in more than one quarter of the cases to more than 20 years like between 5 and 10 years. About half of the doctors said they were vaccinated against other pathologies: hepatitis A (34.5%), the yellow fever (21.1%), the thyphoid fever (12.5%), the BCG (8.9%), the pneumococcus (6.6%), meningitis and variola (5%). In the French Community, the vaccine coverage of the general practitioners against the influenza (67%), tetanus (83%) and hepatitis B (73%) is, in this study, higher or equal to the other Belgian and international studies but remains insufficient. A bad vaccine coverage is observed concerning rubella, the whooping-cough, the poliomyelitis. The answers over the durations of protection of the vaccines are rather disparate and show a bad knowledge of these durations and diagrams of vaccination. An update of this knowledge could be carried out during the continuous medical trainings.

Adolescent↗

PubMed2005

Surgical treatment of primary hyperparathyroidism.

BACKGROUND: With the use of routine calcium evaluation, the incidence of primary hyperparathyroidism (pHPT) has considerably increased. The aim of our study was the assessment of the morbidity and the outcome of surgically treated patients with pHPT. METHODS: The charts of 279 patients (204 female, 75 male, median age: 58 years) who underwent surgery for pHPT between 1989 and 1999 were retrospectively reviewed. A follow-up was carried out on 235 patients after a mean period of 3.6 years (0.2-10 years). RESULTS: In 148 patients a unilateral, and in 130 patients a bilateral approach was taken. Transplanted parathyroid tissue was removed from the left forearm of one patient. At follow-up persistent hypocalcemia was seen in 30 patients (20 after bilateral, 10 after unilateral exploration). 6 patients (1 after bilateral, 5 after unilateral exploration) revealed a newly developed persistent paresis of the recurrent laryngeal nerve. In 5 patients persistent (1 after unilateral, 4 after bilateral exploration) and in 5 patients recurrent (2 after unilateral, 3 after bilateral exploration) pHPT could be observed. CONCLUSION: Both unilateral and bilateral cervical exploration for pHPT have a high rate of success with a low morbidity. Therefore, patients with assumed asymptomatic pHPT with unspecific neuropsychological abnormalities should also be evaluated for surgical intervention.

Female↗

PubMed2005

Strong reproductive skew among males in the multiply mated swordtail Xiphophorus multilineatus (Teleostei).

Male swordtails in the genus Xiphophorus display a conspicuous ventral elongation of the caudal fin, the sword, which arose through sexual selection due to female preference. Females mate regularly and are able to store sperm for at least 6 months. If multiple mating is frequent, this would raise the intriguing question about the role of female choice and male-male competition in shaping the mating system of these fishes. Size-dependent alternate mating strategies occur in Xiphophorus; one such strategy is courtship with a sigmoid display by large dominant males, while the other is gonopodial thrusting, in which small subordinate males sneak copulations. Using microsatellite markers, we observed a frequency of multiple paternity in wild-caught Xiphophorus multilineatus in 28% of families analyzed, but the actual frequency of multiple mating suggested by the correction factor PrDM was 33%. The number of fathers contributing genetically to the brood ranged from one to three. Compared to other species in the family Poeciliidae, both frequency and degree of multiple paternity were low. Paternity was found to be highly skewed, with one male on average contributing more than 70% to the offspring. Hence in this Xiphophorus mating system, typically one male dominates and sneaker males do not appear to be particularly effective. Postcopulatory mechanisms, however, such as sperm competition, are also indicated by our data, using sex-linked phenotypes among the offspring.

Animals↗

PubMed2005

Scattering curves of ordered mesoscopic materials.

Analytical expressions for the scattering functions of ordered mesoscopic materials are derived and compared to experimentally determined scattering curves. Ordered structures comprising spheres (fcc, bcc, hcp, sc), cylinders (hex, sq), and lamellar structures are considered. The expressions take into account particle size distributions and lattice point deviations, domain size, core/shell structures, as well as peak shapes varying analytically between Lorentzian and Gaussian functions. The expressions allow one to quantitatively describe high-resolution synchrotron small-angle X-ray (SAXS) and neutron scattering (SANS) curves from lipid and block copolymer lyotropic phases, core/shell nanoparticle superstructures, ordered nanocomposites, and ordered mesoporous materials. In addition, the diffuse out-of-plane scattering of grazing incidence GISAXS and GISANS experiments of laterally ordered thin films can be quantitatively analyzed.

Lipids↗

PubMed2005

Outcome following single vs bilateral lung transplantation in recipients 60 years of age and older.

AIMS: The significant shortage of donor organs in lung transplantation necessitates a careful selection of lung transplant recipients. The outcome of lung transplant recipients aged 60 years and older has not been analyzed systematically. METHODS: We retrospectively reviewed our experience with older recipients. Between January 1999 and July 2003, 248 patients underwent lung transplantation at our institution, of which 18 were aged 60 years and older (7.3%, range 60-66, mean 62 +/- 1.1). RESULTS: Eleven (61%) of the recipients 60 years and older received a single (SLTx) and seven (39%), a bilateral lung transplant. Donor age in the single transplant cohort was 30 +/- 4 years. It was 33 +/- 3 years in bilateral patients. Posttransplant ventilation time was significantly different among groups, with 282 +/- 32 hours after bilateral and 56 +/- 13 hours after transplant (P < .05). Also significantly longer was the length of the ICU stay in the bilateral group. First PaO2 in the ICU was not different among the two groups. The 1-year survival in the single transplant group was significantly better compared to the bilateral group with 73% versus 43%, respectively. CONCLUSIONS: The 1-year survival following lung transplantation in patients older than 60 years is markedly reduced compared to recipients under 60 years of age. If a lung transplant is considered in a recipient above the age of 60 years, a single transplant should be favoured. If that is not indicated, patients over 60 should be very carefully selected for bilateral transplant.

Aged↗

PubMed2005

[Contribution of in vivo confocal microscopy to limbal tumor evaluation].

PURPOSE: To explore tumors of the limbus with a new in vivo confocal microscope and to compare the images to histology results. METHODS: We evaluated three tumors in three patients with the Heidelberg Retina Tomograph II, Rostock Cornea Module. A diagnostic and therapeutic excision with adjunctive cryotherapy was performed for each individual. Confocal microscopy was compared to histopathologic sections. RESULTS: Histology identified two dysplasias and one carcinoma in situ. The main pathological features were visible on our images: cytonuclear atypias, epithelial folds into an inflammatory and vascularized conjunctival stroma, fine vessels perpendicular to the surface, a clear limit with normal epithelium, papillomatous organization, and abnormal keratinization. CONCLUSION: Our preliminary study showed that this type of limbal tumor could be explored using in vivo confocal microscopy. We were not able to determine whether there was a microinvasion. This new method could be a diagnostic aid, especially for atypical lesions and for follow-up because of frequent recurrences. Other studies are necessary to confirm our hypothesis.

Adult↗