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Biomedical subjects

C Becker

Publications and source records attributed to C Becker.

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

[On the way to isotopic spatial resolution: technical principles and applications of 16-slice CT].

The broad introduction of multi-slice CT by all major vendors in 1998 was a milestone with regard to extended volume coverage, improved axial resolution and better utilization of the tube output. New clinical applications such as CT-examinations of the heart and the coronary arteries became possible. Despite all promising advances, some limitations remain for 4-slice CT systems. They come close to isotropic resolution, but do not fully reach it in routine clinical applications. Cardiac CT-examinations require careful patient selection. The new generation of multi-slice CT-systems offer simultaneous acquisition of up to 16 sub-millimeter slices and improved temporal resolution for cardiac examinations by means of reduced gantry rotation time (0.4 s). In this overview article we present the basic technical principles and potential applications of 16-slice technology for the example of a 16-slice CT-system (SOMATOM Sensation 16, Siemens AG, Forchheim). We discuss detector design and dose efficiency as well as spiral scan- and reconstruction techniques. At comparable slice thickness, 16-slice CT-systems have a better dose efficiency than 4-slice CT-systems. The cone-beam geometry of the measurement rays requires new reconstruction approaches, an example is the adaptive multiple plane reconstruction, AMPR. First clinical experience indicates that sub-millimeter slice width in combination with reduced gantry rotation-time improves the clinical stability of cardiac examinations and expands the spectrum of patients accessible to cardiac CT. 16-slice CT-systems have the potential to cover even large scan ranges with sub-millimeter slices at considerably reduced examination times, thus approaching the goal of routine isotropic imaging.

Cardiovascular Diseases↗
PubMed2005

Factors relating to the use of physical restraints in psychogeriatric care: a paradigm for elder abuse.

The purpose of this study was to address one component of the complex topic "elder abuse". A prospective observational study in the psychogeriatric unit of an acute psychiatric hospital demonstrated that 30% (n=37) of all included patients (n=122) were physically restrained. The highest incidence (48%) was found in elderly patients with severe cognitive impairments (diagnosis of dementia and/or delirium) (n=60). The most commonly used devices of physical restraints were bed rails (100%), belts (trunk 93%, limbs 40%) and chair-tables ("gerichair") (41%). Most restraints occurred at the beginning of hospitalization (83%). Physical restraints were continued for many days and on average of many hours a day. Patients with low cognitive status and serious mobility impairments showed a very high risk of being restrained (p=0.015; OR 32.0 [95% CI:2.0-515.1]). Inability to perform ADL activities increased the frequency of restraint use (p=0.035; OR27.7 [95%CI: 1.3-604.1]). As possible co-factors repetitive disruptive behaviors were found. There was no significant difference between the frequency of falls in restrained or unrestrained patients during the observational period, but fall-related fractures (n=2) only occurred in restrained patients. It is possible that restraints increase the use of benzodiazepines and classical neuroleptics. These results confirm that physical restraints remain a common practice in psychogeriatric care. No evidence-based data support the value of restraints in regard to fall prevention and control of behavioral disturbances in elderly people with serious mental illness. In contrast, these devices can have serious adverse effects and mean one of the most severe interventions in fundamental human rights.

Accidental Falls↗
PubMed2005

[Effectiveness of a multifactorial intervention to reduce physical restraints in nursing home residents with dementia].

At present, observational studies and expert opinion are the best evidence for the use of physical restraints. Large regional and national disparities are described in acute and long-term care. Epidemiological data demonstrate a prevalence of 3-5% body-fixed or near body restraint devices. The hip fracture rate in Germany are approximately 50 per 1000 resident years. Between 40-50% of the residents in nursing homes are treated with psycho-tropic medication potentially limiting their physical mobility. The presented study protocol was designed to test the effectiveness of a multifactorial intervention to reduce physical restraints in long-term care (LTC) residents particularly with cognitive impairment. The intervention consists of an educational and an organizational part to empower staff members to improve their skills and practice in using restraints. Technical devices to reduce fall related injuries are additionally offered to the LTC facilities. The study population includes 200 LTC residents in 54 facilities in three states in Germany. The sample size calculation was based upon a 5% prevalence rate in the control group and an expected reduction of 50% in the intervention group. The protocol is a waiting-list control design. All waiting facilities will be offered to participate after their waiting period. Primary endpoints are the number of restrained residents and resident time (hours) of being restrained. The use of psychotropics, falls, fall-related injuries and the incidence of residents newly being restrained is being monitored. The study starts with a baseline documentation of all facilities followed by randomization and a three month intervention. Change agents will be responsible for the intervention. Technical devices will include a newly developed soft hip protector and sensor mats which notice the intent of leaving the bed. The aim of the study is to develop an evidence-based model for a knowledge transfer project to implement minimum restraint environments in LTC.

Accidental Falls↗
PubMed2005

[Medical care in the nursing home].

The introduction of the German mandatory long-term care insurance in 1995 has led to major changes in the delivery of medical services in nursing homes. This is a result of the assessment process, the demographic changes, modified access to facilities and the changing socioeconomic resources of informal caregivers. The fusion of the health care and long-term care insurance system is now being proposed by bipartisan committees. This will lead to major changes as well as the immediate announced changes of the long-term care insurance. The article gives an overview of these recent developments based on expert opinion.

Economics, Nursing↗
PubMed2005

In vivo imaging of colitis and colon cancer development in mice using high resolution chromoendoscopy.

BACKGROUND: Mouse models of colitis and cancer are indispensable for our understanding of the pathogenesis of these diseases. In the past, mice had to be sacrificed in order to analyse colitis activity and tumour development. We have developed a safe method for high resolution endoscopic monitoring of living mice. METHODS: Mice developing colitis or colonic tumours were anaesthetised using avertine and repeatedly examined by endoscopy. A novel miniendoscope (1.9 mm outer diameter), denoted Coloview, was introduced via the anus and the colon was carefully insufflated with an air pump before analysis of the colonic mucosa. An extra working channel allowed the introduction of biopsy forceps or injection needles as well as surface staining with methylene blue in order to visualise the surface of the crypts and the pit pattern architecture. RESULTS: Endoscopic pictures obtained were of high quality and allowed monitoring and grading of disease. Scoring of colitis activity as well as tumour size and growth was possible. In addition, pit pattern analysis using chromoendoscopy permitted discrimination between inflammatory and neoplastic changes. Biopsies yielded enough tissue for molecular and histopathological analyses. CONCLUSIONS: In summary, chromoendoscopy in mice allows monitoring of the development of colitis and colon cancer with high resolution. Manipulations such as local injection of reagents or taking biopsies can be performed easily.

Animals↗
PubMed2005

Engrafting periodontal fibroblasts with new 3-dimensional polylactide foams.

In clinical periodontics, "tissue engineering" techniques have been developed to guide the regenerative process following periodontal disease. We explored a new shaped biomaterial in order to promote cellular adhesion, proliferation and migration of periodontal cells. Granules of poly-D, L-lactide were foamed in specially designed moulds by a controlled gas-loading process. Explant cultures of periodontal tissue were seeded at different densities on the 3-dimensional scaffolds following analysis of cytotoxicity, cell proliferation and differentiation. The moulding procedure led to porous structures with predetermined tubes for cellular locomotion. Cells adhered to and populated the material's surface and inner cavities while retaining fibroblastic phenotype. An optimal ratio between cellular proliferation and mortality rate was achieved at a seeding density of > 10 6 cells/cm 3 scaffold. We designed modified polylactide scaffolds capable of acting as a stent and a cell carrier matrix. The foaming process is easy, cheap and suitable for commercial production.

Biocompatible Materials↗
PubMed2004

Aorto-iliac multidetector-row CT angiography with low kV settings: improved vessel enhancement and simultaneous reduction of radiation dose.

The aim of the study was to implement an abdominal CT angiography protocol using 100 kVp and to compare SNR and CNR, as well as subjective image quality, to a standard CT angiography protocol using 120 kVp on a 16 detector-row CT scanner. Forty-eight patients were referred for routine abdominal CT angiography on a 16 detector-row CT scanner. Patients were scanned using either 120 or 100 kVp at constant mAs settings. Vessel opacification was provided by automated contrast injection using similar injection protocols. Density measurements were performed along the aorto-iliac axis with SNR and CNR calculation. In addition, the estimated effective patient radiation dose was calculated. Results of both protocols were compared. The 100-kVp protocol (432+/-80 HU) showed a significantly higher vessel density than the 120-kVp (333+/-90 HU; P<0.001) protocol, corresponding to an average increase in signal intensity of 30.7%. SNR (36.0 vs 37.0) and CNR (31.1 vs 31.7) for the 100-kV protocol were not significantly lower that those for the standard protocol (P=0.79 and P=0.87), whilst the average estimated dose was significantly lower using the 100-kVp protocol (6.7+/-0.4 vs 10.1+/-1.2 mSv; P<0.0001). Tube kVp reduction from 120 to 100 kVp allows for significant reduction of patient dose in abdominal CT angiography, without significant change in SNR,CNR and image quality.

Adult↗
PubMed2004

[Technique and possibilities of cardiac computed tomography].

Electron beam computed tomography no longer has a role to play in Germany. In contrast, multidetector spiral CT has great potential for replacing some coronary catheter studies, in particular for the exclusion of coronary artery disease, and this in particular since the forthcoming introduction of a 64-slice MDCT scanner promises a further improvement in temporal and special resolution. Currently, however it is no alternative to invasive angiography, since quantification of coronary stenoses is not possible; nor can a diagnostic evaluation be made in the presence of coronary calcifications or intracoronary stents. In particular, however, before applying CT angiography to the heart, the patient groups that can benefit from this method must be defined, especially in light of the fact that radiation exposure is three times as high as with diagnostic coronary catheterization.

Coronary Angiography↗
PubMed2004

Improving balance by improving motor skills.

The effectiveness of a computer-assisted balance training was compared with a home based exercise program in healthy elderly subjects. Twenty-four physically active community dwelling elderly (median age 71 years) participated in the study. Balance was assessed by a summary performance score, measuring postural stability while standing, reaching, stepping and walking. Subjects of the computer-assisted balance training group could considerably improve their performance on the training device (p = 0.0078) as well as in the summary balance score (p = 0.0176). No improvement of balance was documented in the home-based exercise group. A superiority of the computer-assisted balance training exercise protocol over the home-based exercise group could not be documented (p = 0.3934). The study indicates that a computer-assisted balance training, focussing on one motor skill, can improve balance. It is suggested that a home-based exercise program is ineffective to improve balance in elderly persons, if there is no direct supervision.

Aged↗
PubMed2004

Effect of triacylglycerol structure on absorption and metabolism of isotope-labeled palmitic and linoleic acids by humans.

The effect of dietary TAG structure and fatty acid acyl TAG position on palmitic and linoleic acid metabolism was investigated in four middle-aged male subjects. The study design consisted of feeding diets containing 61 g/d of native lard (NL) or randomized lard (RL) for 28 d. Subjects then received an oral dose of either 1,3-tetradeuteriopalmitoyl-2-dideuteriolinoleoyl-rac-glycerol or a mixture of 1,3-dideuteriolinoleoyl-2-tetradeuteriopalmitoyl-rac-glycerol and 1,3-hexadeuteriopalmitoyl-2-tetradeuteriolinoleoyl-rac-glycerol. Methyl esters of plasma lipids isolated from blood samples drawn over a 2-d period were analyzed by GC-MS. Results showed that absorption of the 2H-fatty acids (2H-FA) was not influenced by TAG position. The 2H-FA at the 2-acyl TAG position were 85+/-4.6% retained after absorption. Substantial migration of 2H-16:0 (31.2+/-8.6%) from the sn-2 TAG position to the sn-1,3 position and 2H-18:2n-6 (52.8+/-6.4%) from the sn-1,3 position to the sn-2 position of chylomicron TAG occurred after initial absorption and indicates the presence of a previously unrecognized isomerization mechanism. Incorporation and turnover of the 2H-FA in chylomicron TAG, plasma TAG, and plasma cholesterol esters were not influenced by TAG acyl position. Accretion of 2H-16:0 from the sn-2 TAG position in 1-acylphosphatidylcholine was 1.7 times higher than 2H-16:0 from the sn-1,3 TAG positions. Acyl TAG position did not influence 2H-18:2n-6 incorporation in PC. The concentration of 2H-18:2n-6-derived 2H-20:4n-6 in plasma PC from subjects fed the RL diet was 1.5 times higher than for subjects fed the NL diet, and this result suggests that diets containing 16:0 located at the sn-2 TAG position may inhibit 20:4n-6 synthesis. The overall conclusion is that selective rearrangement of chylomicron TAG structures diminishes but does not totally eliminate the metabolic and physiological effects of dietary TAG structure.

Absorption↗
PubMed2004

Morbidity associated with intraportal islet transplantation.

INTRODUCTION: Complications associated with intraportal islet infusion have been reported. In this study, we analyzed the relationship between occurrence of complications and islet preparation characteristics/infusion technique. METHODS: We reviewed all intraportal islet infusions from 1992 to 2003. RESULTS: Sixteen islet autotransplantations were performed without infusion-related complications. The tissue volume injected was 13 +/- 11 mL with basal and peak portal pressures of 13 +/- 6 and 21 +/- 6 mm Hg. Seventy-seven intraportal islet allotransplantations were performed in 51 patients. Fifteen islet infusions were done by laparotomy during simultaneous islet/kidney transplantation without complication. Among 62 percutaneous transhepatic injections, nine complications (two portal branch thrombosis and seven intra-abdominal hemorrhages) were recorded. Rise in portal pressure was related to tissue volume injected (P <.05). Basal and peak portal pressures were 14 +/- 5 and 18 +/- 6 mm Hg in uncomplicated infusions, 14 +/- 9 and 18 +/- 9 mm Hg in the thrombosis group, and 13 +/- 7 and 18 +/- 5 mm Hg in the hemorrhage group (P >.05). Complications occurred only after percutaneous islet infusion (P <.03). CONCLUSIONS: Procedure-related morbidity of intraportal islet infusion is low. Changes in portal pressure are related to volume of tissue injected but do not seem to be associated with the occurrence of complications. Percutaneous infusion is a minimally invasive procedure, but this advantage must be balanced by the higher rate of complications.

Hemorrhage↗
PubMed2004

Islet of Langerhans allogeneic transplantation at the University of Geneva in the steroid free era in islet after kidney and simultaneous islet-kidney transplantations.

AIMS: We report a single-center experience of islet allogeneic transplantation in islet after kidney (IAK) and simultaneous islet-kidney (SIK) type 1 diabetic recipients using a steroid-free immunosuppressive regimen. METHODS: Eight patients received 12 islet infusions in 5 IAK and 3 SIK procedures. Median age was 51 years (range, 30-58 years) with a male:female ratio of 2:6. IAK was considered only for patients with a stable kidney function and a creatinine clearance level >60 mL/min. SIK was considered for patients with a counterindication for simultaneous kidney-pancreas transplantation. Immunosuppression was based on sirolimus/tacrolimus combined with daclizumab induction. Two consecutive infusions of >5000 islet equivalents (IEQ)/kg were planned. RESULTS: Five patients completed the transplantation course, whereas 3 patients received only 1 islet infusion. All patients have functional grafts (C-peptide >166 pmol/L) at 6-month median follow-up. Of 5 patients who completed their transplantation course 4 became insulin independent. HbA1c and fructosamine decreased over time, showing improved metabolic control. Severe adverse events were observed in 4 patients. One SIK patient died after OKT-3 treatment of severe kidney rejection. CONCLUSIONS: The Edmonton immunosuppressive protocol can be applied for patients undergoing either IAK or SIK procedures, with a high rate of graft function and insulin independence. Morbidity is higher than among patients undergoing solitary islet transplantation for type 1 brittle diabetes.

Adult↗
PubMed2004

Molecular karyotyping using an SNP array for genomewide genotyping.

BACKGROUND: Chromosomal imbalances are a major cause of developmental defects as well as cancer and often constitute the key in identification of novel disease related genes. Classical cytogenetic methods are limited in resolution and dependent on highly skilled labour, while methods with higher resolution, based on molecular cytogenetics approaches such as matrix CGH, are not widely available. METHODS: We have developed and evaluated a method we term "molecular karyotyping", using readily available and easy to handle oligonucleotide arrays originally designed for parallel genomewide analysis of over 10,000 SNPs. We show that we can easily and reliably detect unbalanced chromosomal aberrations of various sizes from as little as 250 ng of DNA on a single microarray, based on fluorescence intensity information from clusters of SNPs. RESULTS: We determined the resolution of this method through analysis of 20 trios with 21 previously confirmed subtle aberrations sizing between 0.2 and 13 Mb. Duplications and deletions of at least 5 Mb in size were reliably detectable, but detection of smaller aberrations was dependent on the number of SNPs they contained, thus seven of 10 different deletions analysed, with sizes ranging from 0.2 to 3.7 Mb, were not detectable due to insufficient SNP densitiy in the respective region. CONCLUSIONS: Deduction of reliable cut off levels for array peaks in our series of well characterised patients allows the use of the GeneChip Mapping 10K SNP array for performing rapid molecular karyotyping from small amounts of DNA for the detection of even subtle deletions and duplications with high sensitivity and specificity.

Chromosome Aberrations↗
PubMed2003

Risk indicators for falls in institutionalized frail elderly.

The aim of this study was to identify individual predisposing risk indicators for falls in a sample of institutionalized frail elderly in southern Germany. The design was a prospective observational study with a 1-year follow-up (October 1998-September 1999). The study population included 472 long-term-care residents whose mean age was 84 years; 77% were female. Risk indicators for accidental falls were analyzed by using logistic regression. Residents were found to have an incidence density rate of falls of 2,558 per 1,000 resident-years. Multiple logistic regression analysis revealed short-term memory loss, transfer assistance, urinary incontinence, positive fall history, and use of trunk restraints as predictors of falls. In a further logistic regression analysis, depressive symptoms, transfer assistance, urinary incontinence, and positive fall history were associated with frequent falls. Using these risk indicators as a screening procedure to identify fallers would be easy to administer and could be accomplished by nursing staff. Study results encourage specifically addressing urinary incontinence, cognitive impairment, use of restraints, depression, and transfer difficulties as modifiable predisposing risk factors for falls. Fall history represents an important nonmodifiable marker to identify residents at high risk.

Accidental Falls↗
PubMed2003

[Rare cause of a chest pain].

HISTORY AND ADMISSION FINDINGS: A 42-year-old woman was admitted because of a newly perceived pain localized in the ventral part of the fifth left rib. The physical examination was normal except for a palpable nodular thyroid and pain on palpation of this rib. The patient history contained a serious car accident and severe cigarette abuse. DIAGNOSTIC PROCEDURES: The chest x-ray in "bone technique" showed an osteolysis in the fifth left rib, which was confirmed by computer tomography and bone scan. The high resolution CT scan of the lung revealed a discrete interstitial reticular pattern with minor cystic alterations without lymph node enlargement. DIAGNOSIS, THERAPY AND CLINICAL COURSE: Transbronchial biopsy, bronchoalveolar lavage and a malignancy screening did not lead to a diagnosis. Therefore, the patient was submitted to partial rib resection and open lung biopsy. Histological examination revealed a Langerhans cell histiocytosis. The initial therapeutic approach was a strict smoking cessation. CONCLUSION: The differential diagnosis of a lytic bone lesion in a heavy smoker should include Langerhans cell histiocytosis. On smoking cessation a remission of the disease may be achieved.

Adult↗