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PubMed2001

Ferula harmonis 'zallouh' and enhancing erectile function in rats: efficacy and toxicity study.

Ferula harmonis, which is locally called 'zallouh' in the Middle East, is used as an aphrodisiac as it is reputed to enhance male sexual behavior, however, there is no scientific verification. In this study, the oil extracted from the seeds of Ferula harmonis was tested for its efficacy in enhancing erectile function and toxicity in male rats. The sexual activities assessed by penile erection index were dose dependent. The ED(50) (12.03 mg/kg) was 880 times less than the LD(50) (10.6 g/kg). However, when doses ranging from 0.05, 0.5 to 2 g/kg were given daily for 28 days, acute and subacute toxicity were observed. There was a decrease in total body weight, hepatomegaly, atrophic testis, significant decrease in hemoglobin and red blood cell count. In addition, there was a significant decrease in cholesterol level. All the above indicate that the crude oil from the plant Ferula harmonis can enhance erectile function, however, it becomes toxic if it is used for a long period of time. Further studies are underway to isolate and identify the active ingredients and their exact mechanisms of action.

Animals↗
PubMed2006

Two-dimensional ionization chamber arrays for IMRT plan verification.

In this paper we describe a concept for dosimetric treatment plan verification using two-dimensional ionization chamber arrays. Two different versions of the 2D-ARRAY (PTW-Freiburg, Germany) will be presented, a matrix of 16 x 16 chambers (chamber cross section 8 mm x 8 mm; the distance between chamber centers, 16 mm) and a matrix of 27 x 27 chambers (chamber cross section 5 mm x 5 mm; the distance between chamber centers is 10 mm). The two-dimensional response function of a single chamber is experimentally determined by scanning it with a slit beam. For dosimetric plan verification, the expected two-dimensional distribution of the array signals is calculated via convolution of the planned dose distribution, obtained from the treatment planning system, with the two-dimensional response function of a single chamber. By comparing the measured two-dimensional distribution of the array signals with the expected one, a distribution of deviations is obtained that can be subjected to verification criteria, such as the gamma index criterion. As an example, this verification method is discussed for one sequence of an IMRT plan. The error detection capability is demonstrated in a case study. Both versions of two-dimensional ionization chamber arrays, together with the developed treatment plan verification strategy, have been found to provide a suitable and easy-to-handle quality assurance instrument for IMRT.

Computer-Aided Design↗
PubMed1989

Interhemispheric transfer in patients with incomplete section of the corpus callosum. Anatomic verification with magnetic resonance imaging.

Tests of interhemispheric disconnection including visual, somesthetic, kinesthetic, auditory, and complex motor functions were performed on seven patients with chronic epilepsy who had undergone partial surgical section of the corpus callosum, verified by magnetic resonance imaging. Two patients with only one third of the splenium remaining demonstrated disconnection syndromes involving all modalities except vision, which was completely intact. Five patients had lesions involving the rostrum and the anterior two thirds to four fifths of the body of the callosum, with the splenium spared. They demonstrated little evidence of disconnection in the modalities indicated, except for left ear suppression on a dichotic listening task and partial somatosensory disruption in some cases. These results emphasize the importance of the posterior corpus callosum for interhemispheric sensory and sensorimotor transfer, although some discrepancies between current behavioral data and previous anatomic findings remain.

Adolescent↗
PubMed1998

Portal dose image (PDI) prediction for dosimetric treatment verification in radiotherapy. I. An algorithm for open beams.

A method is presented for calculation of transmission functions for high energy photon beams through patients. These functions are being used in our clinic for prediction of portal dose images (PDIs) which are compared with PDIs measured with an electronic portal imaging device (EPID). The calculations are based on the planning CT-scan of the patient and on the irradiation geometry as determined in the treatment planning process. For each beam quality, the required input data for the algorithm for transmission prediction are derived from a limited number of measured beam data. The method has been tested for a PDI-plane at 160 cm from the focus, in agreement with the fixed focus-to-detector distance of our fluoroscopic EPIDs. For 6, 23 and 25 MV photon beams good agreement (approximately 1%) has been found between calculated and measured transmissions through anthropomorphic phantoms.

Algorithms↗
PubMed2006

[Surgical intervention in patients with malignant glioma].

Glial tumors occur at an incidence from 2 to 10/ 100.000 (Japan vs. Sweden) and building up to 50 % of all patients suffering from brain tumors. 50 % of those are again malignant gliomas Grade III and Grade IV. Despite all therapeutic approaches the median survival for glioblastomas is 15 months and for anaplastic gliomas Grade III 30 months. After diagnosis, preferably by MRI, a neurosurgical procedure is performed under microsurgical guidelines mostly by means of neuronavigation and intraoperative guidance. Depending on the preoperative diagnosis and localisation of the pathologic lesion an open craniotomy or a stereotactic biopsy is performed. This allows the histological verification and decompression and cytoreduction. A gros total safe removal preserving neurological function is the most important goal of surgery. Tumor removal in eloquent areas such as speech area is performed under local anesthesia as an awake operation. Age, Karnofsky performance status, histology as well as radical removal have a significant influence on overall survival. Adjuvant radiotherapy and chemotherapy with Temozolemide have further improved the outcome significantly. The 2-year survival has reached 28 % in most recent studies. Further experimental therapies in controlled trials, such as intratumoral convection-enhanced instillation of immunotoxins and radiopeptids, photodynamic therapy and direct instillation of new formulations of chemotherapeutic drugs (e. g. nanoparticles) are promising new approaches. New developments in the treatment of patients harboring malignant brain tumors allow an individual neurooncological treatment concept to be established to enhance overall survival and quality of life.

Brain↗
PubMed1992

Randomised trial of case finding and surveillance of elderly people at home.

Health screening for old people who live at home has been the subject of debate for 30 years or so. It has come to the fore again in the UK with the new emphasis on annual assessments by general practitioners (GPs) of those aged 75 or more. Screening in the elderly has implications for manpower. How can it best be done? We describe here a randomised, controlled study of case finding and surveillance in patients aged 65 and over in a general practice in South Wales. Problem identification was by a postal questionnaire, focusing on function, that was sent at random to 369 eligible patients with subsequent verification and intervention by a specially appointed nurse. The 356 controls had no questionnaires and no contact with that nurse. The study lasted 3 years, and end-points included mortality, self-ratings of quality of life, and health status, and use of all services (GP contacts, hospital admission, home help, and so on). Mortality was significantly lower in the intervention group (18%) than in the controls (24%) (difference 6.0% [95% CI 0.1-11.9%], p less than 0.05). Total number of hospital admissions did not differ between intervention and control groups, but duration of hospital stay of patients aged 65 to 74 years was significantly shorter in the intervention group (difference 4.6 days [95% CI 1.6-7.6], p less than 0.01). An increase in visits to a GP was largely offset by a lower number of home visits by a GP. Quality-of-life measures revealed no between-group differences, but self-rated health status was superior in the intervention group. We conclude that the use of a postal screening questionnaire with selective follow-up and intervention can favourably influence outcome and use of health care resources by elderly people living at home.

Aged↗
PubMed1988

Control analysis of biochemical pathways: a novel procedure for calculating control coefficients, and an additional theorem for branched pathways.

A novel method for calculating control coefficients of individual enzymes on fluxes and concentrations in metabolic pathways is presented. This method is derived by applying the theorem on implicit functions to the equations defining the steady state metabolite concentrations; it allows verification of the existing summation theorems and connectivity relations, and leads to a novel theorem for flux control coefficients in branched pathways. The method and the novel theorem are illustrated by several examples.

Mathematics↗
PubMed2003

Elucidation of ataxin-3 and ataxin-7 function by integrative bioinformatics.

The spinocerebellar ataxias (SCAs) are a class of hereditary neurodegenerative diseases, which are caused by the pathological expansion of unstable CAG triplet repeats found in a number of apparently unrelated genes. The proteins encoded by the SCA genes typically translate this expanded (CAG)n repeat into an expanded poly(Q) stretch. Several pathological features are common to all SCAs, irrespective of the gene harbouring the expansion. The specific contributions of the mutated genes are currently hard to assess, as the physiological role of most of the so-called ataxins is not known. By combining the results of profile-based sequence analysis with genome-wide functional data available for model organisms, we have derived detailed predictions of the physiological function of two SCA gene products. Ataxin-3, the protein mutated in Machado Joseph Disease (SCA3), belongs to a novel group of cysteine-proteases and is predicted to be active against ubiquitin chains or related substrates. The catalytic site of this enzyme class is similar to that found in UBP and UCH type ubiquitin proteases. For ataxin-7, the gene product of the SCA7 gene, we have identified an orthology relationship to the yeast open reading frame Ygl066c. Recently published evidence from genome-wide studies suggests that Ygl066c is a component of the SAGA histone acetyltransferase complex. By analogy, a similar role for the mammalian ataxin-7 can be expected. The functional predictions reported here are sufficiently precise to allow a direct experimental verification. Moreover, both findings have implications for the general pathogenesis of spinocerebellar ataxias by providing a direct connection of these diseases with ubiquitin metabolism and histone acetylation.

Acetylation↗
PubMed2005

Compton-scattering measurement of diagnostic x-ray spectrum using high-resolution Schottky CdTe detector.

The analysis of x-ray spectra is important for quality assurance (QA) and quality control (QC) of radiographic systems. The aim of this study is to measure the diagnostic x-ray spectra under clinical conditions using a high-resolution Schottky CdTe detector. Under clinical conditions, the direct measurement of a diagnostic spectrum is difficult because of the high photon fluence rates that cause significant detector photon pile-up. An alternative way of measuring the output spectra from a tube is first to measure the 90 deg Compton scattered photons from a given sample. With this set-up detector, pile-up is not a problem. From the scattered spectrum one can then use an energy correction and the Klein-Nishina function to reconstruct the actual spectrum incident upon the scattering sample. The verification of whether our spectra measured by the Compton method are accurate was accomplished by comparing exposure rates calculated from the reconstructed spectra to those measured with an ionization chamber. We used aluminum (Al) filtration ranging in thickness from 0 to 6 mm. The half value layers (HVLs) obtained for a 70 kV beam were 2.78 mm via the ionization chamber measurements and 2.93 mm via the spectral measurements. For a 100 kV beam we obtained 3.98 and 4.32 mm. The small differences in HVLs obtained by both techniques suggest that Compton scatter spectroscopy with a Schottky CdTe detector is suitable for measuring the diagnostic x-ray spectra and useful for QA and QC of clinical x-ray equipment.

Aluminum↗
PubMed2004

Extraction of optical scattering parameters and attenuation compensation in optical coherence tomography images of multilayered tissue structures.

A recently developed analytical optical coherence tomography (OCT) model [Thrane et al., J. Opt. Soc. Am. A 17, 484 (2000)] allows the extraction of optical scattering parameters from OCT images, thereby permitting attenuation compensation in those images. By expanding this theoretical model, we have developed a new method for extracting optical scattering parameters from multilayered tissue structures in vivo. To verify this, we used a Monte Carlo (MC) OCT model as a numerical phantom to simulate the OCT signal for heterogeneous multilayered tissue. Excellent agreement between the extracted values of the optical scattering properties of the different layers and the corresponding input reference values of the MC simulation was obtained, which demonstrates the feasibility of the method for in vivo applications. This is to our knowledge the first time such verification has been obtained, and the results hold promise for expanding the functional imaging capabilities of OCT.

Algorithms↗
PubMed1999

[Use of a cyclotron in the production of positron emitting radionuclides].

The experience acquired by our center during the first two years of using cyclotron 18/9 (IBA) dedicated to the production of clinical positron emission radionuclides is described. The cyclotron performance characteristics, production yields, quality control and synthesized radiotracers are analyzed. Cyclotron makes it possible to produce up to 3,300 mCi of 18F-, 270 mCi of 18F2, 3,100 mCi of 11C, 502 mCi of 13N (in 120, 60, 35 and 20 minutes respectively) and 540 mCi/min of 15O. In our center, about 85% of the PET studies are performed with 18F-FDG, whereas the remaining are done with 15O-water, 11C-bicarbonate, 11C-methionine, 13N-ammonia or 18F-. Cyclotron is included in the Radiopharmacy Unit of our PET facility and is subjected to a global quality control program. Follow-up of the bombardment parameters and periodic verifications of the cyclotron performance have made it possible to prevent equipment functioning problems, increase mean time between stoppage and decrease downtime. We conclude that cyclotron has high production capabilities and allows enough flexibility for a clinical and research positron emission tomography center; furthermore, it can also be used for regional distribution of 18F-FDG to satellite PET centers.

Carbon Radioisotopes↗
PubMed2002

A comparative study on kernel-based probabilistic neural networks for speaker verification.

This paper compares kernel-based probabilistic neural networks for speaker verification based on 138 speakers of the YOHO corpus. Experimental evaluations using probabilistic decision-based neural networks (PDBNNs), Gaussian mixture models (GMMs) and elliptical basis function networks (EBFNs) as speaker models were conducted. The original training algorithm of PDBNNs was also modified to make PDBNNs appropriate for speaker verification. Results show that the equal error rate obtained by PDBNNs and GMMs is less than that of EBFNs (0.33% vs. 0.48%), suggesting that GMM- and PDBNN-based speaker models outperform the EBFN ones. This work also finds that the globally supervised learning of PDBNNs is able to find decision thresholds that not only maintain the false acceptance rates to a low level but also reduce their variation, whereas the ad-hoc threshold-determination approach used by the EBFNs and GMMs causes a large variation in the error rates. This property makes the performance of PDBNN-based systems more predictable.

Algorithms↗
PubMed2001

A feasible method for clinical delivery verification and dose reconstruction in tomotherapy.

Delivery verification is the process in which the energy fluence delivered during a treatment is verified. This verified energy fluence can be used in conjunction with an image in the treatment position to reconstruct the full three-dimensional dose deposited. A method for delivery verification that utilizes a measured database of detector signal is described in this work. This database is a function of two parameters, radiological path-length and detector-to-phantom distance, both of which are computed from a CT image taken at the time of delivery. Such a database was generated and used to perform delivery verification and dose reconstruction. Two experiments were conducted: a simulated prostate delivery on an inhomogeneous abdominal phantom, and a nasopharyngeal delivery on a dog cadaver. For both cases, it was found that the verified fluence and dose results using the database approach agreed very well with those using previously developed and proven techniques. Delivery verification with a measured database and CT image at the time of treatment is an accurate procedure for tomotherapy. The database eliminates the need for any patient-specific, pre- or post-treatment measurements. Moreover, such an approach creates an opportunity for accurate, real-time delivery verification and dose reconstruction given fast image reconstruction and dose computation tools.

Animals↗
PubMed2002

Half-width of intensity profiles of light scattered from self-affine fractal random surfaces and simulational verifications.

Based on the fact that the half-width of the Fourier transform is inversely proportional to that of a symmetrical primary decay function, the half-width of the intensity profiles of light scattered from self-affine fractal random surfaces in the whole k( perpendicular ) region is studied. The primary function, whose Fourier transform is the intensity profile, is approximated with a simple mathematical decay function by equating their half-widths and maximums. The expression obtained for the half-width of the scattered intensity profiles reduces to the present results in the two extreme cases with the scattering roughness factors being either very small or very large. For a complete verification, we perform a simulation of the light scattering, in which self-affine fractal random surfaces are generated with an algorithm that is an analogy to the formation of laser speckles. The simulated and theoretical results conform well.

Journal Article↗
PubMed2002

Usefulness of dynamic magnetic resonance pancreatography with secretin [correction of secretion] injection for evaluating pancreatic exocrine function after pancreatogastric reconstructive surgery.

BACKGROUND/PURPOSE: The usefulness of dynamic magnetic resonance pancreatography (MRP) with secretin injection as a new method of assessing pancreatic exocrine function was evaluated in patients undergoing pancreatogastrostomy. METHODS: A series of 12 patients who had undergone pancreatogastrostomy were classified into group 1 (9 patients whose pancreas was normal preoperatively) and group 2 (3 patients with a firm pancreas accompanied by distended pancreatic ducts). The pancreatic exocrine function was evaluated using the changes in maximum pancreatic duct diameter and the intensity ratio calculated by tracing the contour line on the images of pancreatic juice secretion newly occurring after dynamic MRP with prior secretin injection. RESULTS: Clear visualization of the pancreatic duct by MRP was achieved in all 12 patients, and a decrease in pancreatic duct diameter was evident postoperatively in group 2. Pancreatic juice secretion was well visualized on MRP images following secretin injection in 10 patients but not in 2 patients of group 2. Higher intensity ratios were noted in group 1 than in group 2. CONCLUSIONS: Dynamic MRP with secretion injection enables clear verification of pancreatic juice secretion on images and permits objective evaluation of pancreatic exocrine function. It therefore is a useful procedure for assessing pancreatic exocrine function after resection of the pancreas.

Adult↗
PubMed2002

Pheochromocytomas: detection with 18F DOPA whole body PET--initial results..

PURPOSE: To evaluate fluorine 18 ((18)F) dihydroxyphenylalanine (DOPA) whole-body positron emission tomography (PET) as a biochemical imaging approach for detection of pheochromocytomas. MATERIALS AND METHODS: (18)F DOPA PET and magnetic resonance (MR) imaging were performed in 14 consecutive patients suspected of having pheochromocytomas (five sporadic, nine with von Hippel-Lindau disease); metaiodobenzylguanidine (MIBG) scintigraphy was performed in 12 of these patients. The individual imaging findings were assessed in consensus by specialists in nuclear medicine and radiologists blinded to the results of the other methods. The findings of the functional imaging methods were compared with those of MR imaging, the reference standard. Histologic verification could be obtained in eight patients with nine tumors. RESULTS: Seventeen pheochromocytomas (11 solitary, three bifocal; 14 adrenal, three extraadrenal) were detected with MR imaging. (18)F DOPA PET and MR imaging had concordant results in all 17 tumors. In contrast, MIBG scintigraphy had false-negative results in four patients with three adrenal tumors smaller than 2 cm and one extraadrenal tumor with a diameter of 3.6 cm. On the basis of these data, sensitivities of 100% for (18)F DOPA PET and of 71% for MIBG scintigraphy were calculated. Specificity was 100% for both procedures. CONCLUSION: (18)F DOPA PET is highly sensitive and specific for detection of pheochromocytomas and has potential as the functional imaging method of the future.

Adolescent↗
PubMed1991

Time spent in state-recommended functions by consultant dietitians in Wisconsin skilled nursing facilities.

In this study we determined how consultant dietitians working in Wisconsin skilled nursing facilities distributed their time among contracted duties. At the time of the study, the 400 skilled nursing facilities in Wisconsin employed 160 consultant dietitians. Of these, 135 consultant dietitians were eligible to participate in the study. A mailed questionnaire was used to collect data on educational background, experience, and actual time spent in state-recommended functions, additional resident-care functions, and additional non-resident-care functions. Completed, usable questionnaires were returned by 65 (48%) of the 135 consultant dietitians. Data were analyzed statistically and presented as medians, means, and standard deviations. Mean time (minutes) consultant dietitians spent per resident admission activity was as follows: data collection, 31.3; care planning, 28.9; resident counseling, 18.5; medical record review, 17.7; discharge referral, 15.4. Mean time (minutes) consultant dietitians spent per month in other activities was as follows: facility evaluation, 75.3; student training, 120; allied staff training, 38.7; foodservice staff training, 46.8; technician training, 128; menu planning, 76.9; diet manual review, 21.6; quality assurance programs, 31.8; quality assurance audits, 34; report preparation for facility administrator, 33.4; and policy development, 32.8. Mean times reported in this study may be used as time guidelines by the state of Wisconsin for evaluating how skilled nursing facilities contract for services of consultant dietitians. Other state and federal regulatory agencies could use the time guidelines for comparison and verification until future studies provide more data on time standards for state-recommended functions, additional resident-care functions, and additional non-resident-care functions.

Consultants↗
PubMed2004

Anaerobic biodegradation of aircraft deicing fluid in UASB reactors.

A central composite design was employed to methodically investigate anaerobic treatment of aircraft deicing fluid (ADF) in bench-scale Upflow Anaerobic Sludge Blanket (UASB) reactors. A total of 23 runs at 17 different operating conditions (0.8% 1.6% ADF (6000-12,000mg/L COD), 12-56h HRT, and 18-36gVSS/L) were conducted in continuous mode. The development of four empirical models describing process responses (i.e. COD removal efficiency, biomass-specific acetoclastic activity, methane production rate, and methane production potential) as functions of ADF concentration, hydraulic retention time, and biomass concentration is presented. Model verification indicated that predicted responses (COD removal efficiencies, biomass-specific acetoclastic activity, and methane production rates and potential) were in good agreement with experimental results. Biomass-specific acetoclastic activity was improved two-fold from 0.23gCOD/gVSS/d for inoculum to a maximum of 0.55gCOD/gVSS/d during ADF treatment in UASB reactors. For the design window, COD removal efficiencies were higher than 90%. The predicted methane production potentials were close to theoretical values, and methane production rates increased as the organic loading rate is increased. ADF toxicity effects were evident for 1.6% ADF at medium organic loadings (SOLR above 0.5gCOD/gVSS/d). In contrast, good reactor stability and excellent COD removal efficiencies were achieved at 1.2% ADF for reactor loadings approaching that of highly loaded systems (0.73gCOD/gVSS/d).

Acetates↗