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Biomedical subjects

J Weber

Publications and source records attributed to J Weber.

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

Dynamic 3D MR angiography of intra- and extracranial vascular malformations at 3T: a technical note.

Time-resolved, contrast-enhanced 3D MR angiography combined with parallel imaging at 3T was applied to an intracranial arteriovenous malformation, a dural arteriovenous fistula, and an extracranial facial arteriovenous malformation. The temporal resolution was one image every 1.5 seconds. Arterial feeders were depicted in all three cases. Early venous drainage was observed in the intracerebral arteriovenous malformation and the dural arteriovenous fistula, but not in the facial arteriovenous malformation. All findings were concordant with conventional angiography.

Adult↗
PubMed2005

Long-term analysis of the resistance development in HIV-1 positive patients treated with protease and reverse transcriptase inhibitors: correlation of the genotype and disease progression.

In this study, 27 HIV-1-positive patients on long-term highly active antiretroviral therapy (HAART) in the Czech Republic were followed for a period of up to 7 years. Variability of the HIV-1 protease (PR) sequence common in the Czech Republic was observed. Under the pressure of inhibitors of protease (PRIs) and reverse transcriptase (RTIs) mutations in PR were detected. Development of resistance to PRIs was followed by a decrease in CD4 count and increase in viral load. The dynamics of viral load closely corresponded to the accumulation of specific primary mutations in PR and RT. Out of 27 patients 18 developed resistance to PRIs and the prolonged therapy led to the accumulation of a higher number of amino acid changes associated with the resistance and, consequently, cross-resistance to several PRIs was observed. These multi-resistant variants of HIV-1 with mutations in PR could not be inhibited sufficiently with PRIs that are currently available in clinical practice. Efficient yet temporary suppression of viral replication was achieved by a lopinavir (LPV) treatment.

Amino Acid Substitution↗
PubMed2004

[The script concordance test: a new evaluation method of both clinical reasoning and skills in internal medicine].

OBJECTIVE: The script concordance test is designed to evaluate knowledge organization, which constitutes a crucial parameter of clinical skills. The objective of the present study was to assess the value of a new written evaluation tool to measure clinical skills in Internal Medicine. MATERIALS AND METHODS: A 95-item examination was completed by a group of medical students (N =17), a group of residents in Family practice (N =9), a group of residents in Internal Medicine (N =5), and a group of experienced physicians in Internal Medicine (N =7). The scores obtained were compared by analysis of variance. The reliability of the test was studied by calculating Cronbach's coefficient alpha. RESULTS: The mean score was 220.3 +/-41.7 for medical students, 230.5 +/-31.7 for residents in Family practice, 274.2 +/-32.2 for residents in Internal Medicine, and 352.1 +/-22.9 for experienced physicians in Internal Medicine. The differences observed between the scores for the various groups were significant (P <0.0001). Moreover, the value of Cronbach's coefficient alpha was 0.81 in the whole examination. CONCLUSION: Our data indicate that the script concordance test may easily allow to differentiate various levels of clinical skills in Internal Medicine. Moreover, because of Cronbach's coefficient alpha as high as 0.81, our findings suggest the validity of this test in Internal Medicine.

Diagnostic Tests, Routine↗
PubMed2004

[Proposed scoring system for assessment of functional impairment due to visual field defects].

INTRODUCTION: The purpose of the study is the development of a scoring system for the assessment of functional impairment due to visual field defects, based on the Esterman grid, but adapted to the existing system in the Federal Republic of Germany. METHODS: The score areas and the evaluation rules were altered iteratively, until the functional score by the new system matched as much as possible the score obtained from the existing system of geometrical defect patterns. RESULTS: The visual field is divided into 100 score areas, which are smaller in the visual field center and in its lower region, respectively. The areas inside the reference isopter are counted and taken as total function in percent. Areas with monocular perception are rated with 3/4 points. Functional impairment is defined as the difference of total function to 100%. For 9 of 20 defect patterns, the functional scores are equal. Another six patterns differ by 1-4%. The remaining 5 of 20 patterns differ by 6-8% in either direction. CONCLUSION: The new system is easier to apply, more consistent, and covers irregular defect patterns. The level of functional impairment is nearly identical with both systems. A transition to the scoring system would considerably increase the certitude and the quality of assessment especially in difficult cases.

Disability Evaluation↗
PubMed2004

Increased prevalence of and gene transcription by Chlamydia pneumoniae in cerebrospinal fluid of patients with relapsing-remitting multiple sclerosis.

Microbial agents may play a role in the pathogenesis of multiple sclerosis (MS). C. pneumoniae has been recently associated with MS; however, study results are at variance. We tested the hypothesis that Chlamydia pneumoniae-specific DNA and RNA are more often detected in cerebrospinal fluid (CSF) of patients with multiple sclerosis than patients with other neurological diseases (OND). We investigated CSF samples from 84 patients with definite MS and 89 OND patients (n = 62 with normal CSF; n = 27 with pathological CSF) using a nested polymerase chain reaction (PCR) to detect ompA gene sequences of C. pneumoniae. In subjects with positive PCR, we probed for chlamydial heat shock protein 60-mRNA and 16S-rRNA by reverse transcriptase (rt)-PCR. C. pneumoniae-specific DNA was more often detected in MS patients (50 %) than in all OND patients combined (28.1%, p = 0.003) and in OND patients with normal CSF (24.2%, p = 0.003) but not than in OND patients with pathological CSF (37%, p = 0.24). In relapsing-remitting MS (n = 55), the prevalence of C. pneumoniae DNA was higher (66.7 %) than in both OND subgroups (p <or= 0.05). In MS patients (n = 20), chlamydial heat shock protein 60-mRNA (75%) and 16S-rRNA (70%) were more often detected than in OND patients (n = 16; 18.8%; p < 0.005). Although more often detected in remitting-relapsing MS, C. pneumoniae DNA in CSF is not specific for MS owing to its high prevalence in OND controls. However, the higher rate of gene transcription suggests a more active metabolism of C. pneumoniae in MS patients.

Adult↗
PubMed2004

[Unilateral decompressive craniectomy in left transverse and sigmoid sinus thrombosis].

Cerebral venous and dural sinus thrombosis is a rare cause of stroke. We explore the controversial issue of anticoagulation therapy and indication for decompressive craniectomy in association with severe sinus thrombosis. The 62-year-old female patient was admitted to hospital, because of first generalized seizure. A computed tomographic (CT) scan of the brain revealed a left occipital hemorrhage. Digital subtraction angiogram showing thrombosis of the left transverse and sigmoid sinus. An intravenously administered regimen of heparin was begun, because of a protein S deficiency. On the 6th day the patients level of consciousness deteriorated, necessitating intubation, hyperventilation, and mannitol. Repeat CT scan revealed increasing edema with midline shift and obliteration of the basal cisterns, although the hemorrhagic lesion was unchanged. The patient developed signs of diencephalic dysfunction. A large left temporoparietooccipital craniectomy was performed and the dura was opened. The multiloculated intraparenchymatous hemorrhage portion of the brain was not removed. In addition, the patient was treated postoperatively with heparin therapy for three months, than a regimen of phenprocoumon was begun. Twelve months later the hemianopsia had not improved and she had an incomplete Wernicke's dysphasia. When, despite adequate anticoagulation therapy and intensive care, neurological deterioration occurs in sigmoideus and/or transversus dural sinus thrombosis with unilateral edema, a decompressive craniectomy should be considered especially in young patients.

Anticoagulants↗
PubMed2004

Declining prevalence of STI in the London sex industry, 1985 to 2002.

OBJECTIVES: To describe major changes in the London sex industry between 1985 and 2002 and assess the implications for sexually transmitted infection (STI) risk. METHOD: A descriptive study comparing women who first attended a sex work clinic between 1996 and 2002 and those first attending from 1985 to 1992; a nested case-control study. 1050 female sex workers took part. The setting was a specialist clinical service for sex workers based in a London genitourinary medicine (GUM) clinic, and fieldwork in west London. The main outcome measures were reported condom use and prevalent STI. RESULTS: Over the period of the study there was a significant increase in the proportion of sex workers not born in the United Kingdom (from 25% to 63%, p < 0.001), and women entered sex work at an older age (median 24 years compared with 20 years, p < 0.001). Condom use increased (with the exception of oral sex). There was a significant decline in the proportion of participants reporting a previous STI (32% compared with 80%, p < 0.001) and the prevalence of acute STI declined from 25% to 8% (p < 0.001). Acute STI was associated with younger age, younger age at first sex work, being new to sex work, and inconsistent condom use. In a multivariate analysis unprotected sex with clients was the only significant risk. CONCLUSION: Major restructuring of the sex industry, including the shift to a primarily migrant workforce, has been associated with a steep decline in acute STI, undermining popular assumptions that migrant sex workers are central to the ongoing STI epidemic. We attribute the decline in acute STI to an increase in safer sex.

Adolescent↗
PubMed2004

Receptor technology--cell binding to P-15: a new method of regenerating bone quickly and safely-preliminary histomorphometrical and mechanical results in sinus floor augmentations.

Modern implantology involves the application and optimization of bone engineering biomaterials and scaffolds to achieve predictability in quality and quantity of the regeneration result and to avoid the high morbidity factor of the present gold standard. In this respect, acceleration of (woven) bone formation and completeness of the regeneration result seems to be an reasonable attempt by multiplication of the whole cascades by duplicating all phases of cell binding, migration, proliferation and differentiation. Collagen I is an extracellular matrix protein with multiple main binding domains for osteogenic progenitor cells and therefore plays a crucial role in osteogenesis. PepGen P15 is the first man engineered collagen I binding domain for potential osteoblasts and is able to multiply the complete regeneration cascade. The article explains the principles of micromolecular receptor engineering and its application in sinus floor augmentations as a preliminary report. It presents the first clinical and histomorphometrical results of this new technology in sinus floor elevations. The future potential of individual bone regeneration will be discussed.

Adult↗
PubMed2003

Deletion of chromosome region 18q21.1 --> 18q21.3 in a patient without clinical features of the 18q- phenotype.

In a 16-month-old boy referred because of developmental delay and asymmetric motor development, chromosome analysis showed an aberrant chromosome 18 in all 25 metaphases examined. The chromosome aberration was initially interpreted either as an interstitial deletion of chromosome region 18q21.1 --> 18q21.3 or an unbalanced translocation involving the distal part of the long arm of chromosome 18. Chromosome microdissection in combination with fluorescence in situ hybridization demonstrated that the aberrant chromosome 18 had an interstitial deletion, the karyotype being: 46,XY,del(18)(q21.1q21.3). At age 27 months, his development was moderately retarded. He showed craniofacial asymmetry but no other anomalies. The clinical and cytogenetic findings are compared with previously reported patients with a terminal or interstitial deletion in the long arm of chromosome 18.

Chromosome Banding↗
PubMed2003

Understanding the formation of new clusters of alkali and alkaline Earth metals: a new synthetic approach, single-crystal structures, and theoretical calculations.

A new synthetic approach, reacting alkaline earth metal iodides with butyllithium, lithium hydroxide, and/or lithium butoxide under salt elimination, is presented, giving access to some interesting clusters of calcium, strontium, and barium, partially in combination with lithium. The so far largest calcium cluster Li[[Ca(7)(mu(3)-OH)(8)I(6)(thf)(12)](2)(mu(2)-I)].3THF, 4, and the new strontium compound [Sr(3)I(3)(OH)(2)(thf)(9)]I, 5, are shown to feature common building blocks of OH-capped M(3) triangles. On the basis of mainly electrostatic interactions, these clusters are not volatile. By introducing LiO(t)Bu, the two clusters [IM(O(t)Bu)(4)[Li(thf)](4)(OH)] (6, M = Sr; 7, M = Ba) are prepared, 7 exhibiting volatility as an important physical property, which makes it a potential precursor for chemical vapor deposition. The structural relationship between 4, 5, 6, and 7 and their respective starting materials is shown, and possible reaction mechanisms are proposed. Exhibiting surprising and new structural motifs, the bonding modes of these clusters are investigated by the electron localization function as well as by ab initio calculations.

Journal Article↗
PubMed2003

First-principles calculations of pseudolocal vibrational modes: the case of Cu and Cu pairs in Si.

Pseudolocal vibrational modes (pLVMs) are defect-related vibrational modes which are localized despite being below the phonon maximum. Such modes are sometimes seen as phonon replicas in photoluminescence spectra. The pLVMs associated with two copper-related defects are calculated from first-principles density-functional theory in periodic supercells. The localization of the pLVMs is quantified using the magnitude of the eigenvectors of the dynamical matrix.

Journal Article↗
PubMed2003

Concomitant renal cell carcinoma with pituitary adenoma.

Renal cell carcinoma has a complex and variable natural history. We report a case underlining this who presented concomitant renal cell carcinoma metastasis with pituitary and adrenocortical adenomas. A 62-year-old woman presented with visual loss. Imaging revealed a large sellar mass with suprasellar extension. Four years before, nephrectomy and adrenalectomy had been performed for a renal cell carcinoma with metastasis in a coexistent adrenocortical adenoma. Faced with progressive visual loss and the questionable pituitary pathology, the patient underwent trans-sphenoidal surgery. Due to profuse tumor bleeding, only a biopsy was possible. In a second operation, the patient underwent craniotomy with subtotal resection of the tumor. Histological examination of the specimen revealed a metastasis of the renal cell carcinoma and a pituitary adenoma. The case presented here and a review of the reports suggest that there are some differences between the clinical features and outcomes of metastases of renal cell carcinoma and those of pituitary gland metastases from other primary sites.

Adrenal Cortex Neoplasms↗
PubMed2003

Continuous-flow metal biosorption in a regenerable Sargassum column.

Metal biosorption behavior of raw seaweed S. filipendula in ten consecutive sorption-desorption cycles has been investigated in a packed-bed flow-through column during a continuous removal of copper from a 35mg/L aqueous solution at pH 5. The elutant used was a 1% (w/v) CaCl2/HCl-solution at pH 3. The sorption and desorption was carried out for an average of 85 and 15h, respectively, representing more than 41 days of continuous use of the biosorbent. The weight loss of biomass after this time was 21.6%. The Cu-biosorption capacity of the biomass, based on the initial dry weight, remained relatively constant at approximately 38 mg Cu/g. Loss of sorption performance was indicated by a shortening breakthrough time and a broadening mass-transfer zone. The column service time, considered up to 1 mg Cu/L in the effluent, decreased continuously from 25.4 h for the first to 12.7 h for the last cycle. The critical bed length, representing the mass-transfer zone, increased almost linearly from 28 to 34cm. "Life-factors" for S. filipendula were found to be 0.0008h(-1) for the breakthrough time and 0.008cm/h for the critical bed length, using an exponential decay and linear fitting functions, respectively. Regeneration with CaCl2/HCl at pH 3 provided elution efficiencies up to 100%. Maximum concentration factors were determined to be in the range 16-44, a decreasing tendency was observed with an increasing exposure time.

Adsorption↗
PubMed2003

Analysis of 3D kinematics concerning three different clubs in golf swing.

Although many professionals have produced books or videotapes which offer a novel approach to the game, a review of the scientific literature reports limited research evaluating the actual biomechanics of the golf swing in comparison with other sports. The aim of this study was to investigate the influence of kinematic pattern in golf swing using three different clubs: driver, five-iron, pitching-wedge. These three golf clubs have been chosen for their available range of ball flight. The measures of kinematic data during swing were established with the optoelectronic system VICON (Oxford's Metrics, Oxford, UK) with five cameras operating at 50 frames per second. Clubhead speed was measured using a swing made detector (Bell-Tronics, Ltd, Covington, USA). Seven right-handed male golfers with a high level of skill participated in the study. The results showed that there was an identical timing (movement time and proportion for each phase of the swing) between the three clubs tested, but the kinematics and the clubhead speed were different depending on the three different clubs used.

Adolescent↗
PubMed2003

Level of evidence as a future gold standard for the content quality of health resources on the internet.

OBJECTIVE: An assessment of the quality of health information on the Internet is an absolute necessity. In this study 'sensitive' information was defined as information found in documents published on the Internet, which could be used in a medical decision. For sensitive information, the main criterion chosen for the quality of the information was an indication of the level of evidence. A survey was conducted using the CISMeF health catalogue to assess how often a score of the level of evidence is mentioned in the information accessible on the Internet in French-language health resources. METHODS: Since 1999, members of the CISMeF team have systematically been searching for all documents containing 'sensitive' information and verifying whether the level of evidence was explicitly indicated as a score at least once in the document. RESULTS: As of June 2001, 10,190 resources were included in CISMeF; including 2964 textual 'sensitive' resources (29.1%). Out of all these resources, only 4.7% (95% confidence interval: 4.0 - 5.5%) indicated the level of evidence. A statistically significant difference in the prevalence of indicating the level of evidence according to resource types (e.g., 18.1% for guidelines compared to 0.0% for teaching material), year of publication (almost three times greater in 1997-2001 compared with 1990-1996) and publishers was observed. CONCLUSION: As the number of people accessing the growing amount of information on the Internet is increasing daily, publishers have an ethical obligation to inform their readers about the validity of 'sensitive' information their sites contain. However, the vast majority of the French language Internet resources that were surveyed do not mention a score of the level of evidence for their sensitive information.

Consensus↗