Biomedical subjects

A Beck

Publications and source records attributed to A Beck.

At least 37 records · Page 2Linked to original sources

PubMed2005

[The physics of vacuum therapy].

BACKGROUND: Vacuum therapy is a routine and successful method for wound treatment and for the temporary covering of soft-tissue defects. It is an occlusive method that can be used for treating acute, chronic and infected wounds. To date, no data are available regarding secretion transit times and pressure conditions in lesions treated with vacuum therapy. The present study had as its objectives to examine the mechanisms of vacuum therapy and determine the effects of physical forces on the wound surface with the purpose of formulating recommendations for pressure settings using the various available vacuum pumps. MATERIAL AND METHODS: Using an appropriate model, we measured secretion transit times and pressures using two different vacuum therapy pads. We then conducted pressure measurements during dressing change in eight patients with wound surfaces greater than 20 cm(2). RESULTS: The secretion transit times remained unchanged with the polyvinyl alcohol (PVA) pad and a negative pressure of 40 kPa, but decreased by about 50 % when the black polyurethane (PU) pad was used. Pressure measurements showed that, at this negative pressure, there was only a slight positive external pressure of 31 mmHg on the wound surface. CONCLUSION: When the PVA pad is used, negative pressures greater than 40 kPa should be applied in order to effect a maximum transit of wound secretion and prolongation of the use of the vacuum dressing. When the PU pad is used, the applied negative pressure can be lower due to the pad's larger pores, as recommended by Argenta and Morykwas. An excessive external pressure on the wound surface does not occur.

Biophysical Phenomena↗

PubMed2005

[Assessment of two different software solutions for the evaluation of CT colonography].

PURPOSE: To compare a commercial CT colonography software ("Colonography", Siemens, Forchheim) with a non-commercial post-processing system ("Colotux", Department of Informatics). MATERIAL AND METHODS: Identical data sets of 10 patients, who underwent an ultra-low-dose multi-detector CT colonography (ULD-MDCTC) (4x1 mm collimation, 8 mm pitch, 120 kVp, 10 mAs) were analyzed retrospectively. Assessment was performed using both software solutions by two resident radiologists, who did not have any experience with any colonography software tool before and who did not know the clinical symptoms of the patients or the results of the conventional colonoscopy. Both systems were analyzed using several subjective quality criteria including workflow, handling, image quality, endoluminal navigation and analysis of lesions with grading on a 5-point-scale. Results concerning polyps were compared between the two systems as well as with conventional colonoscopy. RESULTS: Both colonography systems detected the same number of polyps. Although both showed some advantages for single criteria, no relevant difference was noted in general for subjective assessment. The time for calculation of three dimensional interactive volumes was three times longer for "Colotux" compared to "Colonography." Linux-based "Colotux" showed a trend towards better subjective image quality and easier measurement of polyp size. An intuitive desktop and "Syngo"-workflow integration were advantages of "Colonography." CONCLUSION: The analysis of CT colonographies (4-detector-row-CT-scanner, ultra low dose technique, supine position) can adequately be achieved by both software solutions. There was no significant subjective or objective difference of quality between a "stand-alone" individual system and a commercial workflow-integrated solution. A relevant factor for decision between the two systems may be the difference in time needed for the 3D volume calculation, especially in institutes with a high frequency of examinations.

Aged↗

PubMed2005

An unusual case of early fulminant post-traumatic fat embolism syndrome.

A multiple-injured patient developed a very early onset fulminant fat embolism syndrome that was partially masked by haemorrhagic shock. Despite early diagnosis by transoesophageal echocardiography and aggressive symptomatic treatment, there was a rapid evolution to death. Post mortem examination revealed the presence of both pulmonary and systemic fat emboli. This case highlights the ever present risk of masked fat embolism syndrome shortly after trauma.

Echocardiography, Transesophageal↗

PubMed2005

"We don't really have cause to discuss these things, they don't affect us": a collaborative model for developing culturally appropriate sexual health services with the Bangladeshi community of Tower Hamlets.

OBJECTIVE: To identify barriers to accessing sexual health care among the Bangladeshi community of east London and to develop a model of community participation in service development. METHODS: Qualitative study using one to one interviews with sexual health service users plus focus groups in community settings. RESULTS: 58 people participated in the study, 12 in individual interviews and the remainder in six focus groups. All were of Bangladeshi origin. Four main themes were reported as impacting on access to services; confidentiality concerns, relevance of services to the community, problems with discussing sexual issues, and problems with previous experiences of health promotion. Community values regarding sex outside of marriage were an important underlying factor in participants' responses. Existing sexual health services were seen as culturally insensitive by patients and community groups. CONCLUSIONS: Community based health initiatives among hard to reach ethnic minority groups should use existing networks of statutory and non-statutory groups to benefit from local expertise and relationships. Steering groups composed of members of the local communities served by the clinic can usefully inform service development.

Adult↗

PubMed2005

Test bed for assessment of the kinematical determination of navigation systems for total knee arthroplasty. Does a limited range of motion of the hip joint influence the accuracy of the determination?

OBJECTIVE: To locate the rotational center of the hip joint, CT-less navigation systems for artificial knee-joint replacement use movements of the femur with a rigid body attached. It cannot be assumed that the hip joint provides free mobility at all times. The purpose of the present study was: 1) To build a mechanical model to assess the system's accuracy in locating the rotational center of the hip by simulating a step-wise reduction of the range of motion (ROM) of the hip joint. 2) To determine the system's resolution by assessing a critical distance between two positions of the same femoral rigid body during the process of locating the rotational center of the hip. 3) To determine the sensitivity of the navigation system to the rotation of a femoral rigid body relative to the femoral bone while locating the rotational center of the hip joint. MATERIAL AND METHODS: To assess the impact that a limited ROM of the hip joint has on the accuracy of determination of the hip joint's rotational center, a test bed was built. This enables validation of the algorithm used by a CT-less navigation system. RESULTS: In the first part of the study, it was shown that a reduction of the ROM of the hip joint to 30% of its initial value had no evident influence on the accuracy of locating the rotational center of the joint. In the second part of the study, it was determined that the limit of resolution between two spatial points of the pivoting process is between 4.4 and 8.7 cm. The third part of the study showed that the examined system rejected the determination of the hip center even when the rigid body was only rotated through 22.5 degrees . CONCLUSIONS: The results show that osteoarthritis of the hip with a limited ROM, for example, cannot be taken as a contraindication for the use of the evaluated CT-less navigation system. However, the surgeon should ensure that the pivoting of the femur is performed without hindrance within the free range of motion of the hip joint. In accordance with the vendor's recommendation, a minimum distance of 10 cm should be maintained between two spatial points. To ensure safe and unconstrained operation, the rigid body must be firmly attached to the bone and must not be dislocated.

Arthroplasty, Replacement, Knee↗

PubMed2004

Effect of asimadoline, a kappa opioid agonist, on pain induced by colonic distension in patients with irritable bowel syndrome.

BACKGROUND: Visceral hypersensitivity plays a major role in irritable bowel syndrome pathophysiology. Opioid kappa receptors on afferent nerves may modulate it and be the target for new irritable bowel syndrome treatments. AIM: This study evaluated the effect of the kappa opioid agonist asimadoline on perception of colonic distension and colonic compliance in irritable bowel syndrome patients. METHOD: Twenty irritable bowel syndrome female patients (Rome II criteria; 40 +/- 13 years) and hypersensitivity to colonic distension (Pain threshold < or = 32 mmHg) were included in a randomized double-blind cross-over trial comparing the effect of a single oral dose of asimadoline 0.5 mg or placebo on sensory thresholds (defined as a constant and sustained sensation) elicited by left colon phasic distension (5 mmHg steps, 5 min) up to a sensation of abdominal pain. Colonic compliance was compared by the slope of the pressure-volume curves. RESULTS: On asimadoline, pain threshold (mean +/- s.d.) (29.8 +/- 7.2 mmHg) was higher than on placebo (26.3 +/- 7.8 mmHg), difference not statistically significant (P = 0.1756, ANOVA). Area under curve of pain intensity rated at each distension step was significantly lower on asimadoline (89.3 +/- 33.9, ANOVA) than on placebo (108.1 +/- 29.7) (P = 0.0411). Thresholds of perception of nonpainful distensions were not altered on asimadoline, as compared with placebo. Colonic compliance was not different on placebo and asimadoline. CONCLUSION: Asimadoline decreases overall perception of pain over a wide range of pressure distension of the colon in irritable bowel syndrome patients, without altering its compliance. These data suggest that further studies should explore the potential benefit of asimadoline in treatment of pain in irritable bowel syndrome patients.

Acetamides↗

PubMed2004

Stimulus-response versus stimulus-stimulus-response learning in cerebellar patients.

Ample evidence exists that the cerebellum is involved in associative motor learning, particularly in eyeblink-conditioning. In visuomotor associative learning the role of the cerebellum is less clear. One open question is whether cerebellar patients' deficits in visuomotor learning are present both in a stimulus-response and a stimulus-stimulus-response association task. Twelve patients with cerebellar degeneration and 12 healthy matched control subjects participated. A magnetic resonance imaging (MRI) volumetric analysis of the cerebellum was performed to assess the degree of cerebellar atrophy. In a blocked design, subjects had to learn the association between one color square or two color squares and a right or left key press. In the latter condition, the two colors were shown one after the other in the same sequence except for two blocks at the end of the experiment. Overall, cerebellar subjects reacted significantly slower than controls. In both groups, reaction time decreased over blocks, and the learning effect was more pronounced in the stimulus-response than in the stimulus-stimulus-response condition. Post hoc analyses revealed that learning differences between conditions were significant in cerebellar patients but not control subjects. Furthermore, only healthy subjects were irritated, i.e., they significantly increased reaction times in the blocks with reversed sequence in the stimulus-stimulus-response condition. Cerebellar subjects tended to name less correct stimulus-stimulus-response associations after the experiment. Finally, cerebellar volume correlated with parameters of motor performance, but not learning. In conclusion, cerebellar patients showed deficits in stimulus-stimulus-response, but not stimulus-response learning. Future experiments are needed to differentiate between possible deficits in learning the stimulus-stimulus association, use of sequence information, and/or impaired motor performance interfering with learning.

Adult↗

PubMed2004

Complete nucleotide sequence of the RNA 1 of a grapevine isolate of Arabis mosaic virus.

The complete nucleotide sequence of the genomic RNA 1 of the grapevine isolate NW (Neustadt an der Weinstrasse) of Arabis mosaic virus (ArMV) was determined. It is 7334 nucleotides long excluding the poly(A) tail, and contains one long open reading frame encoding a polypeptide of 2284 amino acids. The 5' and 3' non-coding regions were 227 and 252 nucleotides long respectively, and showed stretches of high identity with the corresponding 5' and 3' non-coding regions of ArMV-NW RNA 2. The analysis of the amino acid sequence of the polyprotein encoded by the RNA 1 of the ArMV-NW showed that the conserved amino acid motifs, characteristic for the viral protease co-factor, the NTP-binding protein, the cystein protease, and the RdRp core domains, were all present. Amino acid sequence comparisons between the polyproteins encoded by the RNAs 1 of ArMV-NW and other nepoviruses showed 75% identity with the GFLV-F13, and up to 36% with other nepoviruses.

Genome, Viral↗

PubMed2004

Difference in metallic wear distribution released from commercially pure titanium compared with stainless steel plates.

INTRODUCTION: Stainless steel and commercially pure titanium are widely used materials in orthopedic implants. However, it is still being controversially discussed whether there are significant differences in tissue reaction and metallic release, which should result in a recommendation for preferred use in clinical practice. MATERIALS AND METHODS: A comparative study was performed using 14 stainless steel and 8 commercially pure titanium plates retrieved after a 12-month implantation period. To avoid contamination of the tissue with the elements under investigation, surgical instruments made of zirconium dioxide were used. The tissue samples were analyzed histologically and by inductively coupled plasma atomic emission spectrometry (ICP-AES) for accumulation of the metals Fe, Cr, Mo, Ni, and Ti in the local tissues. Implant corrosion was determined by the use of scanning electron microscopy (SEM). RESULTS: With grades 2 or higher in 9 implants, steel plates revealed a higher extent of corrosion in the SEM compared with titanium, where only one implant showed corrosion grade 2. Metal uptake of all measured ions (Fe, Cr, Mo, Ni) was significantly increased after stainless steel implantation, whereas titanium revealed only high concentrations for Ti. For the two implant materials, a different distribution of the accumulated metals was found by histological examination. Whereas specimens after steel implantation revealed a diffuse siderosis of connective tissue cells, those after titanium exhibited occasionally a focal siderosis due to implantation-associated bleeding. Neither titanium- nor stainless steel-loaded tissues revealed any signs of foreign-body reaction. CONCLUSION: We conclude from the increased release of toxic, allergic, and potentially carcinogenic ions adjacent to stainless steel that commercially pure Ti should be treated as the preferred material for osteosyntheses if a removal of the implant is not intended. However, neither material provoked a foreign-body reaction in the local tissues, thus cpTi cannot be recommend as the 'golden standard' for osteosynthesis material in general.

Adipose Tissue↗

PubMed2004

Genetic immunization and comprehensive screening approaches in HLA-A2 transgenic mice lead to the identification of three novel epitopes in hepatitis C virus NS3 antigen.

Interferon-gamma (IFN gamma)-producing CD8+ T cells have been shown to play a key role in the control or eradication of hepatitis C virus (HCV) infections. In particular, T cells specific of the non-structural protein 3 (NS3) are often associated with control of viremia. The aim of the study was to identify novel HLA-A2 restricted CD8+ T cell epitopes specific of NS3 using a combination of comprehensive approaches. HLA-A2.1 transgenic mice were immunized with a DNA vaccine optimized for NS3 specific epitope presentation and induced CD8+ T cell reactivity was screened using 42 algorithm-predicted peptides as well as a library of 78 overlapping 15-mer peptides spanning the whole protein. Three epitopes mapping within the NS3 protease (GLL: aa 1038-1047) or helicase (ATL: aa 1260-1268 and TLH: aa 1617-1625) were identified. These epitopes, which display similar and high in vitro binding capacities to soluble HLA-A2 molecules, are able to induce either cytotoxic T lymphocytes (CTL) and/or IFN gamma-producing T cells. Comparative in vitro target cell sensitization studies revealed a higher immunogenicity of the GLL peptide as compared with both ATL and TLH peptides. This peptide was capable to recall in vitro HCV-specific IFN gamma and IL-10-producing T cells from peripheral blood mononuclear cells (PBMC) of chronically infected patients. These data increase the pool of NS3-specific CD8+ T cell epitopes available to analyze HCV associated immunity and could contribute to the design and evaluation of candidate vaccines.

Amino Acid Sequence↗

PubMed2004

[Diagnostic apparatus in the shock trauma room].

Opinions vary with regard to the equipment and structural furnishings required for adequate management of the trauma patient in the dedicated shock suite. In order to assess the current situation in Germany, we conducted a survey of the 76 centers participating in the Polytrauma Registry of the DGU. Fifty-one questionnaires were returned by centers representing all levels of care. Responses revealed, for example, that not all centers possess capabilities for conventional radiography in the shock suite (7/51). Only 20 centers had a fixed table; the remaining 24 hospitals used either an image converter or a mobile X-ray unit. A dedicated ultrasound scanner was provided for the shock suite in 39 of 51 centers responding. Dedicated computed tomography scanners were provided for the shock suite in only eight centers (one dedicated trauma center, three level 3 centers, four university hospitals). All eight scanners use helical CT technology; at least three of the units are 8- or 16-slice. Of 51 shock suites, 12 are air-conditioned in compliance with sterile criteria (and are officially designated as surgical suites), while the remaining 39 are not. In acute cases, emergency surgeries can be performed in the shock suite in 37 centers, but not in the remaining 14 shock suites. According to the survey, slightly less than half of the hospitals responding are un-satisfied with the shock suite infrastructure ( n=24) and, of these, 13 centers are actively planning changes (the necessary financial resources have been guaranteed in 10 centers). Fourteen centers desire changes but do not currently have the required money. Information provided by Philips and Siemens suggests that the cost of furnishing a new shock suite ranges between 1.4 and 1.7 million euros. Responses to our survey show that a large gap remains between wishes and reality in the technical infrastructure in many shock suites in Germany.

Diagnostic Equipment↗

PubMed2004

[Magnetic resonance tomography guided focussed ultrasound surgery (MRgFUS) in tumor therapy--a new noninvasive therapy option].

The demand for minimal or non-invasive therapies especially in tumor therapy is increasing constantly. High frequency focussed ultrasound represents an effective and safe alternative to established thermoablative procedures. In this article we report the advantages of MR-guidance for focussed ultrasound. We describe first clinical experiences in the treatment of uterine fibroids, breast cancer and fibroadenomas of the breast employing MR-guided focussed ultrasound surgery (MRgFUS). This method offers strong potential in the treatment also of other tumorentities since it provides excellent accuracy. Currently numerous efforts are undertaken to introduce MRgFUS for the therapy of liver or cerebral tumors.

Breast Neoplasms↗

PubMed2004

Carbohydrate moieties of molluscan Rapana venosa hemocyanin.

Using Zn2+ ions as new method, several FUs have been isolated from molluscan Hc Rapana venosa without formation of non-functional proteolytic side products. N-terminal sequences of these fragments in comparison with FUS from other gastropodan Hcs show a very high degree of structural identity. Four Fus, purified from enzyme-treated structural subunits RvH1 and RvH2 (RvH1-a, RvH1-f, RvH2-a and RvH2-e) show identical N-terminal sequences compared to fragments isolated after treatment with Zn2+ ions. However, in some cases trypsin cleaves RvH chains at different positions if compared to the Zn2+ treatment. To analyze the oligosaccharide composition of two FUS from the first structural subunit of Rapana Hc, RvH1-a and RvH1-f, several techniques were applied: capillary electrophoresis, MALDI-MS, ESI-MS in combination with glycosidase digestions. On basis of these results and the determined amino acid sequence two N-linkage sites were identified in the FU RvH1-a, but only one in the FU RvH1-f.

Amino Acid Sequence↗

PubMed2004

Preserved verb generation in patients with cerebellar atrophy.

A role of the right cerebellar hemisphere has been suggested in linguistic functions. Nevertheless, studies of verb generation in cerebellar patients provide inconsistent results. The aim of the present study was to examine verb generation in a larger group of cerebellar patients with well-defined lesions. Ten subjects with degenerative cerebellar disorders and ten healthy matched controls participated. Subjects had to generate verbs to the blocked presentation of photographs of objects (i.e. four blocks of sixteen objects). As control condition, the objects had to be named. Furthermore, dysarthria was quantified by means of a sentence production and syllable repetition task. Volumetric analysis of individual 3D-MR scans was performed to quantify cerebellar atrophy. Cerebellar patients were slower in the sentence production and syllable repetition tasks, and cerebellar volume was decreased compared to controls. Despite cerebellar atrophy and dysarthria, the answers produced did not differ between patients and controls. In addition, both groups revealed the same amount of decrease in verbal reaction time over blocks (i.e. learning). The results suggest that the role of the cerebellum in verb generation is less pronounced than previously suggested.

Adult↗

PubMed2004

[Ultrasound- and fluoroscopy-guided implantation of peripherally inserted central venous catheters (PICCs)].

PURPOSE: Evaluation of ultrasound- and fluoroscopy-guided implantation of peripherally inserted central venous catheters (PICCs). MATERIALS AND METHODS: In 32 patients (12 males, 20 females; mean age 64.1 +/- 11.9 years) with clinical indication for long term central venous catheter (chemotherapy: N = 5; parenteral nutrition and fluid substitution: N = 26; parenteral pain therapy: N = 1) a PICC was placed by an interventional radiologist using ultrasound guidance. RESULTS: The placement of the PICC was technically successful in 31 (96.9%) patients, with placement of 20 single-lumen 5F PICCs, 4 double-lumen 6F PICCs and 7 double-lumen 7F PICCs. The mean duration of catheter usage was 28.4 (2 - 161) days with a total of 910 catheter days. No catheter occlusions were recorded. Two patients developed a superficial venous thrombosis of the upper extremity. The resulting thrombotic rate was 2.2 per 1000 catheter days. No catheter associated infection was recorded. CONCLUSION: The ultrasound guided placement of peripherally inserted central venous catheters (PICCs) via a superficial vein of the upper extremity is a practical alternative to central catheters via central veins.

Adult↗

PubMed2004

[Comparison of different MRI sequences with and without application of Gd-BOPTA as follow-up after LITT].

PURPOSE: Comparison of various MR imaging techniques without and with the application of Gd-BOPTA for the follow-up of thermal tumor ablations by means of laser-induced therapy (LITT). MATERIALS AND METHODS: Thermal tumor ablations were performed with LITT in 19 patients showing a local recurrence. The metastases were from colorectal carcinoma in 15 cases (78.9 %) and from cervix, bronchial, gastric and renal carcinoma respectively in one patient each. The size of the metastases before ablation was on average 38.5 mm (min = 25 mm, max = 58 mm). The MRI protocol consisted of T2 UTSE FS, T1 w GRE without and with Gd-BOPTA at an early (20 s post injection) and late stage (> 120 min post injection). Two independent radiologists evaluated image contrast of the local relapse and necrosis in comparison to the surrounding healthy liver parenchyma on a scale from - 10 to + 10. Liver parenchyma was in any sequence 0. Recurrences were confirmed with follow-up examinations in all patients. Statistical analysis was performed by means of Wilcoxon and Kendall's W-test. RESULTS: Both radiologists found absolute ratios for contrast differences between thermal necrosis and local recurrence, with an average of 10.95 for T2 w UTSE FS and of 6.58 for T1 w GRE without, and of 4.05 for T1 w GRE with Gd-BOPTA in the early and of 2.26 in the late stage. Superiority for UTSE FS was significant (p < 0.05). The statistical analysis showed a high agreement for both radiologists for all values (p < 0.001). CONCLUSION: For early detection of local recurrences after thermal ablation T2 w UTSE FS is most suitable. For the detection of new foci, the use of liver specific contrast media is advisable.

Contrast Media↗

PubMed2004

Mothers' expressed emotion towards children with and without intellectual disabilities.

OBJECTIVES: To identify factors associated with maternal expressed emotion (EE) towards their child with intellectual disability (ID). DESIGN AND METHOD: A total of 33 mothers who had a child with ID and at least one child without disabilities between the ages of 4 and 14 years participated in the study. Mothers completed self-assessment questionnaires which addressed their sense of parenting competence, beliefs about child-rearing practices, and their reports of behavioural and emotional problems of their child with ID. Telephone interviews were conducted to assess maternal EE towards the child with ID and towards a sibling using the Five Minute Speech Sample (FMSS; Magana et al. 1986), and also to assess the adaptive behaviour of the child with ID using the Vineland Adaptive Behaviour Scale (VABS; Sparrow et al. 1984). RESULTS: Mothers with high EE towards their child with ID were more satisfied with their parenting ability, and their children had more behaviour problems. Analysis of differential maternal parenting, through comparisons of EE towards their two children, showed that mothers were more negative towards their child with ID for all domains of the FMSS except dissatisfaction. CONCLUSIONS: A small number of factors associated with maternal EE towards children with ID were identified. Differences in maternal EE towards their child with ID and their other child suggest that EE is child-driven rather than a general maternal characteristic. Implications of the data for future research are discussed.

Adolescent↗

PubMed2003

Relevance of primary reduction for the clinical outcome of femoral neck fractures treated with cancellous screws.

INTRODUCTION: Femoral head-preserving treatment for femoral neck fractures with cancellous screws is a method widely performed, but its success depends on the quality of primary reduction. The goal of our study was to evaluate the relevance of reduction quality on the clinical outcome. PATIENTS AND METHODS: We retrospectively analyzed the postoperative reduction result of 39 patients. The angular rotation and the inferior displacement of the proximal fracture fragment were digitally assessed from AP radiographs. The clinical outcome was recorded by a follow-up after a mean 5.5 years. RESULTS: Unsuccessful healing was observed in eight patients, femoral head necrosis in three patients, non-union in two patients, implant loosening in one patient, and posttraumatic arthritis in two patients, all resulting in the need for a total hip replacement. This clinical course was strongly associated with a primary reduction in varus position, whereas reduction in anatomic or valgus angulation had no negative effect on the clinical outcome. An inferior offset was no negative predictor for successful healing. CONCLUSION: We conclude that a non-anatomic reduction in varus angulation significantly increases the risk of healing failure and therefore should be avoided. Reduction in valgus position should be performed if secondary redislocation is imminent.

Adult↗