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Technical Factors (technical + factor)
Selected AbstractsUnlocking the opportunity of tight glycaemic controlDIABETES OBESITY & METABOLISM, Issue 2005Innovative delivery of insulin via the lung As the incidence of diabetes reaches epidemic proportions, the use of new, alternative routes of insulin delivery to manage glycaemic control is becoming an ever more active area of research. The high permeability and large surface area of the lung make it an attractive alternative to subcutaneous (SC) insulin injections. This review discusses the technical factors that influence the efficacy of pulmonary drug delivery and describes how an appreciation of these issues has enabled the design of Exubera®, a novel, non-invasive, pulmonary dry-powder human insulin delivery system currently in development by Pfizer and the sanofi-aventis Group in collaboration with Nektar Therapeutics. While clinical trials of this novel aerosol delivery of insulin are still ongoing in patients with diabetes, the results so far suggest it is simple to use and can provide reproducible doses of insulin in therapeutic amounts with only a few inhalations per dose. In addition, it has been shown to be comparable in terms of efficacy and safety to a conventional SC insulin injection regimen. Delivering aerosolized drugs via the lungs avoids the necessity for SC injections and thereby may increase the patient's acceptability of an insulin-based therapeutic regimen. [source] Predictive factors for esophageal stenosis after endoscopic submucosal dissection for superficial esophageal cancerDISEASES OF THE ESOPHAGUS, Issue 7 2009H. Mizuta SUMMARY Endoscopic submucosal dissection (ESD) has been utilized as an alternative treatment to endoscopic mucosal resection for superficial esophageal cancer. We aimed to evaluate the complications associated with esophageal ESD and elucidate predictive factors for post-ESD stenosis. The study enrolled a total of 42 lesions of superficial esophageal cancer in 33 consecutive patients who underwent ESD in our department. We retrospectively reviewed ESD-associated complications and comparatively analyzed regional and technical factors between cases with and without post-ESD stenosis. The regional factors included location, endoscopic appearance, longitudinal and circumferential tumor sizes, depth of invasion, and lymphatic and vessel invasion. The technical factors included longitudinal and circumferential sizes of mucosal defects, muscle disclosure and cleavage, perforation, and en bloc resection. Esophageal stenosis was defined when a standard endoscope (9.8 mm in diameter) failed to pass through the stenosis. The results showed no cases of delayed bleeding, three cases of insidious perforation (7.1%), two cases of endoscopically confirmed perforation followed by mediastinitis (4.8%), and seven cases of esophageal stenosis (16.7%). Monovalent analysis indicated that the longitudinal and circumferential sizes of the tumor and mucosal defect were significant predictive factors for post-ESD stenosis (P < 0.005). Receiver operating characteristic analysis showed the highest sensitivity and specificity for a circumferential mucosal defect size of more than 71% (100 and 97.1%, respectively), followed by a circumferential tumor size of more than 59% (85.7 and 97.1%, respectively). It is of note that the success rate of en bloc resection was 95.2%, and balloon dilatation was effective for clinical symptoms in all seven patients with post-ESD stenosis. In conclusion, the most frequent complication with ESD was esophageal stenosis, for which the sizes of the tumor and mucosal defect were significant predictive factors. Although ESD enables large en bloc resection of esophageal cancer, practically, in cases with a lesion more than half of the circumference, great care must be taken because of the high risk of post-ESD stenosis. [source] BCR/ABL p210, p190 and p230 fusion genes in 250 Mexican patients with chronic myeloid leukaemia (CML)INTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 3 2002R.M. Arana-Trejo There are two major forms of the BCR/ABL fusion gene, involving ABL exon 2, but including different exons of BCR gene. The transcripts b2a2 or b3a2 code for a p210 protein. Another fusion gene leads to the expression of an e1a2 transcript, which codes for a p190 protein. Another, less common fusion gene is c3a2[e19a2], which encodes a p230 protein. The incidence of one or the other rearrangement in chronic myeloid leukaemia (CML) patients varies in different reported series. This study was designed to determine the frequency of coexpresion of the p210, p190 and p230 transcripts in 250 Mexican patients with CML. We performed nested and multiplex reverse transcriptase polymerase chain reaction (RT-PCR) on bone marrow samples from adult patients and found that all cases were positive for some type of BCR/ABL rearrangement. In 226 (90.4%) patients it was p210, while the remaining 9.6% showed coexpression or one of the transcripts of p190/p210/p230. In 7% of patients with p210 expression there are both isoforms (b3a2/b2a2), presumably the result of alternative splicing. The rate of coexpression of the p190/p210 transcripts was 5%, which is much lower than in other reports. This may be due to the technical factors. These patients had high platelet counts, marked splenomegaly and chromosomal abnormalities in addition to Ph,. Other types of coexpression seen were p210/p230 and p190/p210/p230, in patients with high-risk clinical factors. Our study confirms the occurrence of coexpression of different BCR/ABL transcripts, although the rate (9.6%) was much lower than has been reported in other populations. This may reflect either the sensitivity of the detection techniques used or the possibility of genetic differences between the populations studied. Coexpression may be due to alternative splicing or to phenotypic variation, with clinical courses different from classical CML. [source] Esophageal Temperature During Radiofrequency-Catheter Ablation of Left Atrium: A Three-Dimensional Computer Modeling StudyJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2006FERNANDO HORNERO M.D., Ph.D. Introduction: There is current interest in finding a way to minimize thermal injury in the esophagus during radiofrequency-catheter ablation of the left atrium. Despite the fact that the esophageal temperature is now being monitored during ablation, the influence of different anatomic and technical factors on the temperature rise remains unknown. Methods and Results: We implemented a three-dimensional computational model that included atrial tissue, epicardial fat, esophagus, aorta, and lung, all linked by connective tissue. The finite-element method was used to calculate the esophageal temperature distribution during a procedure of constant-temperature ablation with an 8-mm electrode, under different tissue conditions. Results showed that the distance between electrode and esophagus was the most important anatomic factor in predicting the esophageal temperature rise, the composition of the different tissues being of lesser importance. The measurement of the esophageal temperature in different sites of the lumen offered differences up to 3.7°C, especially for a short electrode,esophagus distance (5 mm). The difference in the convective cooling by circulating blood around electrode and endocardium did not show a significant influence on the esophageal temperature rise. Conclusion: Computer results suggest that (1) the electrode,esophagus distance is the most important anatomic factor; (2) the incorrect positioning of an esophageal temperature probe could give a low reading for the maximum temperature reached in the esophagus; and (3) the different cooling effect of the circulating blood flow at different atrial sites has little impact on the esophageal temperature rise. [source] The Distributional Effects of Public ExpenditureJOURNAL OF ECONOMIC SURVEYS, Issue 3 2000Gerd Schwartz It is commonly agreed that economic policies, including budgetary policies, can have potentially strong distributional effects. Traditional economic analysis held that economic policies affected the income distribution primarily through their impact on the rate of growth. More recently, it has come to be recognised that qualitative aspects of economic growth are probably more important than the rate of growth itself. While recent research has confirmed the potential role of expenditure policies as a redistributive tool, it has also shown that redistribution does not necessarily have to come at the expense of economic growth and efficiency. Although there are substantial analytical and technical problems to be faced in the design of equitable and cost-effective public expenditure programmes, unfavourable distributional outcomes of these programmes can usually be traced more to political and institutional pressures than to purely technical factors. JEL Classification number: H5 [source] Acute and Chronic Pulmonary Vein Reconnection after Atrial Fibrillation Ablation: A Prospective Characterization of Anatomical SitesPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2008KIM RAJAPPAN M.D. Background:Arrhythmia recurrence after atrial fibrillation (AF) ablation is often associated with pulmonary vein reconnection (PVR). We prospectively examined anatomical sites of both acute and chronic PVR. Methods:One hundred and fifty AF patients underwent PV wide encirclement and sites where immediate electrical isolation (EI) occurred were tagged using electroanatomic mapping/CT integration (CartomergeÔ, Biosense Webster, Diamond Bar, CA, USA). After 30 minutes PVs were checked and acute PVR sites marked at reisolation. Chronic PVR sites were marked at the time of repeat procedures. Results:On the left, immediate EI sites were predominantly on the intervenous ridge (IVR) and PV-left atrial appendage (PV-LAA) ridge. On the right they were at the roof, IVR, and floor of the PVs. Ninety-eight of one hundred and fifty patients had PVs checked after >30 minutes. Thirty-two of ninety-eight had acute PVR. This was mostly on the IVR and PV-LAA ridge on the left (88%), and on the roof and IVR on the right (78%). At repeat procedure, 38/39 patients had chronic PVR, predominantly on the IVR (61%) and PV-LAA ridge (21%) on the left, and on the roof, IVR, and floor of the right PVs (79%). There was minimal acute or chronic PVR posteriorly. Acutely PVR occurred close to the immediate EI site 60% of the time, but only 30% of the time chronically. Conclusion:Acute and chronic PVR sites have a preferential distribution. This may be determined by anatomical and technical factors. Knowledge of immediate EI sites may be beneficial acutely, but with chronic PVR a careful survey is required. These findings may help target ablation, improving safety and success. [source] Assessment of Celiac Plexus Block and Neurolysis Outcomes and Technique in the Management of Refractory Visceral Cancer PainPAIN MEDICINE, Issue 1 2010Michael A. Erdek MD ABSTRACT Objective., To assess demographic and clinical factors associated with celiac plexus neurolysis outcomes. Design., Retrospective clinical data analysis. Setting., A tertiary care, academic medical center. Patients., Forty-four patients with terminal visceral (mostly pancreatic) cancer who failed conservative measures. Interventions., Fifty celiac plexus alcohol neurolytic procedures done for pain control after a positive diagnostic block. Outcome Measures., A successful treatment was predefined as >50% pain relief sustained for ,1 month. The following variables were analyzed for their association with treatment outcome: age, gender, duration of pain, origin of tumor, opioid dose, type of radiological guidance used, single- vs double-needle approach, type of block (e.g., antero- vs retrocrural), immediate vs delayed neurolysis, volume of local anesthetic employed for both diagnostic and neurolytic blocks, and use of sedation. Results., Those variables correlated with a positive outcome included lower opioid dose and the absence of sedation. Strong trends for a positive association with outcome were found for the use of computed tomography (vs fluoroscopy), and using <20 mL of local anesthetic for the diagnostic block. Conclusions., Celiac plexus neurolysis may provide intermediate pain relief to a significant percentage of cancer sufferers. Both careful selection of candidates based on clinical variables, and technical factors aimed at enhancing the specificity of blocks may lead to improved outcomes. [source] Molecular Breast Imaging: Advantages and Limitations of a Scintimammographic Technique in Patients with Small Breast TumorsTHE BREAST JOURNAL, Issue 1 2007Michael K. O'Connor PhD Abstract:, Preliminary studies from our laboratory showed that molecular breast imaging (MBI) can reliably detect tumors <2 cm in diameter. This study extends our work to a larger patient population and examines the technical factors that influence the ability of MBI to detect small breast tumors. Following injection of 740 MBq Tc-99m sestamibi, MBI was performed on 100 patients scheduled for biopsy of a lesion suspicious for malignancy that measured <2 cm on mammography or sonography. Using a small field of view gamma camera, patients were imaged in the standard mammographic views using light pain-free compression. Subjective discomfort, breast thickness, the amount of breast tissue in the detector field of view, and breast counts per unit area were measured and recorded. Follow-up was obtained in 99 patients; 53 patients had 67 malignant tumors confirmed at surgery. Of these, 57 of 67 were detected by MBI (sensitivity 85%). Sensitivity was 29%, 86%, and 97% for tumors <5, 6,10, and ,11 mm in diameter, respectively. In seven patients, MBI identified eight additional mammographically occult tumors. Of 47 patients with no evidence of cancer at biopsy or surgery, there were 36 true negative and 11 false positive scans on MBI. MBI has potential for the regular detection of malignant breast tumors less than 2 cm in diameter. Work in progress to optimize the imaging parameters and technique may further improve sensitivity and specificity. [source] FDR Control by the BH Procedure for Two-Sided Correlated Tests with Implications to Gene Expression Data AnalysisBIOMETRICAL JOURNAL, Issue 1 2007Anat Reiner-Benaim Abstract The multiple testing problem attributed to gene expression analysis is challenging not only by its size, but also by possible dependence between the expression levels of different genes resulting from co-regulations of the genes. Furthermore, the measurement errors of these expression levels may be dependent as well since they are subjected to several technical factors. Multiple testing of such data faces the challenge of correlated test statistics. In such a case, the control of the False Discovery Rate (FDR) is not straightforward, and thus demands new approaches and solutions that will address multiplicity while accounting for this dependency. This paper investigates the effects of dependency between bormal test statistics on FDR control in two-sided testing, using the linear step-up procedure (BH) of Benjamini and Hochberg (1995). The case of two multiple hypotheses is examined first. A simulation study offers primary insight into the behavior of the FDR subjected to different levels of correlation and distance between null and alternative means. A theoretical analysis follows in order to obtain explicit upper bounds to the FDR. These results are then extended to more than two multiple tests, thereby offering a better perspective on the effect of the proportion of false null hypotheses, as well as the structure of the test statistics correlation matrix. An example from gene expression data analysis is presented. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Kidney retransplants after initial graft loss to vascular thrombosisCLINICAL TRANSPLANTATION, Issue 1 2001Abhinav Humar Background: Vascular thrombosis early after a kidney transplant is an infrequent but devastating complication. Often, no cause is found. These recipients are generally felt to be good candidates for a retransplant. However, their ideal care at the time of the retransplant and their outcomes have not been well documented. We studied outcomes in 16 retransplant recipients who had lost their first graft early posttransplant (<1 month) to vascular thrombosis. Methods: Of 2 003 kidney transplants between 1 January 1984 and 30 September 1998, we identified 32 recipients who had lost their first graft early posttransplant to vascular thrombosis. Of these 32 recipients, 16 were subsequently retransplanted and detailed chart reviews were done. Results: Of the 16 retransplant recipients, 12 lost their first graft to renal vein thrombosis and 4 to renal artery thrombosis. Thrombosis generally occurred early (mean, 3.6 d). Five recipients underwent a complete hematologic workup to rule out a thrombophilic disorder before their retransplant: 4 had a positive result (presence of antiphospholipid antibodies, n=3; increased homocysteine levels, n=1). These 4 recipients, along with 1 other recipient who had a strong family history of thrombosis, underwent thrombosis prophylaxis at the time of their retransplant. Prophylaxis consisted of low-dose heparin for the first 3,5 d posttransplant, followed by acetylsalicylic acid or Coumadin. Of the 16 retransplant recipients, none developed thrombosis. Of the 5 who underwent thrombosis prophylaxis, none had significant bleeding complications. At a mean follow-up of 5.4 yr, 10 (63%) recipients have functioning grafts. Causes of graft loss in the remaining 6 recipients were death with function (n=5, 31%) and acute rejection (n=1, 6%). Graft and patient survival rates after these 16 retransplants were equivalent to results after primary transplants. The incidence of acute and chronic rejection was also no different (p=ns). Conclusion: Vascular thrombosis in the absence of obvious technical factors should prompt a workup for a thrombophilic disorder before a retransplant. Recipients with an identified disorder should undergo prophylaxis at the time of the retransplant. Results in these retransplant recipients are equivalent to those seen in primary transplant recipients. [source] | ||||||||||