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Sean Collins

Publications and source records attributed to Sean Collins.

9 recordsLinked to original sources
PubMed2006

The association between angiotensin converting enzyme inhibitor or angiotensin receptor blocker use during postischemic acute transplant failure and renal allograft survival.

BACKGROUND: Postischemic acute renal transplant failure occurs in approximately one fourth of all dead donor transplantations. Uncertainty exists regarding the putative association between the use of angiotensin converting enzyme inhibitors (ACEIs) or angiotensin II AT1 receptor blockers (ARBs) and kidney transplant graft survival in patients with delayed allograft function. METHODS: We conducted an open cohort study of all 436 patients who experienced an acute renal transplant failure out of all 2,031 subjects who received their first kidney transplant at the Medical University of Vienna between 1990 and 2003. Actual and functional graft survival was compared between users and nonusers of ACEI/ARB using exposure propensity score models and time-dependent Cox regression models. RESULTS: Ten-year actual graft survival averaged 44% in the ACEI/ARB group, but only 32% in patients without ACEI/ARB (P=0.002). The hazard ratio of actual graft failure was 0.58 (95% confidence interval: 0.35-0.80, P=0.002) for ACEI/ARB users compared with nonconsumers. Seventy-one percent of subjects with ACEI/ARB had a functional graft at 10 years versus 64% of ACEI/ARB nonusers (P=0.027). The hazard ratio of functional graft loss was 0.48 (95% confidence interval: 0.24-0.91, P=0.025). CONCLUSIONS: Use of ACEI/ARB in patients experiencing delayed allograft function was associated with longer actual and functional transplant survival.

Angiotensin II Type 1 Receptor Blockers↗
PubMed2006

C5'- and C3'-sugar radicals produced via photo-excitation of one-electron oxidized adenine in 2'-deoxyadenosine and its derivatives.

We report that photo-excitation of one-electron-oxidized adenine [A(-H)*] in dAdo and its 2'-deoxyribonucleotides leads to formation of deoxyribose sugar radicals in remarkably high yields. Illumination of A(-H)* in dAdo, 3'-dAMP and 5'-dAMP in aqueous glasses at 143 K leads to 80-100% conversion to sugar radicals at C5' and C3'. The position of the phosphate in 5'- and 3'-dAMP is observed to deactivate radical formation at the site of substitution. In addition, the pH has a crucial influence on the site of sugar radical formation; e.g. at pH approximately 5, photo-excitation of A(-H)* in dAdo at 143 K produces mainly C5'* whereas only C3'* is observed at high pH approximately 12. 13C substitution at C5' in dAdo yields 13C anisotropic couplings of (28, 28, 84) G whose isotropic component 46.7 G identifies formation of the near planar C5'*. A beta-13C 16 G isotropic coupling from C3'* is also found. These results are found to be in accord with theoretically calculated 13C couplings at C5' [DFT, B3LYP, 6-31(G) level] for C5'* and C3'*. Calculations using time-dependent density functional theory [TD-DFT B3LYP, 6-31G(d)] confirm that transitions in the near UV and visible induce hole transfer from the base radical to the sugar group leading to sugar radical formation.

Adenine↗
PubMed2006

Comparison of BioGlue reinforced and standard running sutured vesicourethral anastomoses.

OBJECTIVES: To compare a BioGlue-reinforced laparoscopically sutured vesicourethral anastomosis (VUA) with a standard laparoscopically sutured VUA in a porcine model. METHODS: Twelve pigs were divided into two groups. In group 1 (n = 6), a standard laparoscopically sutured VUA was performed. In group 2 (n = 6), a standard laparoscopic sutured VUA was performed, and the anastomosis was reinforced with BioGlue. Groups 1 and 2 were completed consecutively. The animals in both groups were killed at 1 week postoperatively. In all cases, cystography was performed immediately after completion of the anastomosis and at death. At necropsy, the gross findings of the VUA were documented, and each anastomosis was excised en bloc for an extensive histopathologic evaluation of the healing parameters, including inflammation and fibrosis at each tissue level, foreign body reactions, and necrosis. RESULTS: Of the 12 VUAs, 11 were successfully performed laparoscopically. The median operative time for groups 1 and 2 was 70 and 100 minutes, respectively (P = 0.03). The median anastomotic time for groups 1 and 2 was 30 and 50 minutes, respectively (P = 0.02). No difference was seen in urinary extravasation on the cystographic evaluation in the immediate postoperative or 1-week evaluations. At necropsy, a gross complete circumferential histologic tissue approximation was noted in 1 (20%) of 5 pigs in group 1 and 2 (33%) of 6 pigs in group 2 (P = 0.66). No urinomas were noted in either group. Histopathologic evaluation revealed no significant difference between groups 1 and 2 regarding inflammation, fibrosis, foreign body reactions, or necrosis. CONCLUSIONS: The application of BioGlue to the anastomotic line extended the procedure time and did not improve the quality of the VUA.

Anastomosis, Surgical↗
PubMed2006

Update on the epidemiology and biology of renal cortical neoplasms.

A new era is developing in the understanding of the diagnosis, classification, and management of renal-cell carcinoma (RCC). Historically, RCC has been divided into subtypes on the basis of the histopathologic findings alone. Now, genetic alterations, nuclear characteristics, and clinical criteria are routinely incorporated into the classification. The greater use of axial imaging that began in the 1980s dramatically increased the incidence of RCC, but there has not been a decrease in the percentage of cases that are metastatic. Nevertheless, many incidental lesions prove to be benign, so there is renewed enthusiasm for biopsy before treatment is selected. Genetic conditions associated with RCC, such as Von Hippel Lindau and Birt-Hogg-Dube syndromes, along with genetic analyses of tumors, have provided considerable insight into the pathogenesis of these lesions. Renal-cell carcinoma is resistant to chemotherapy, and high-dose interleukin-2 is the only regimen currently approved by the Food and Drug Administration for the treatment of advanced RCC. Stem cell transplantation is an evolving therapy. The vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), platelet-derived growth factor (PDGF), and transforming growth factor-alpha pathways are promising targets for medical therapy of RCC. Bevacizumab, a monoclonal antibody that acts as a competitive blocker of the VEGF receptor; sorafenib, an oral well-tolerated tyrosine kinase inhibitor that blocks the intracellular second-messenger system associated with the VEGF receptor; sunitinib, a multitarget inhibitor of kinases associated with the VEGF and PDGF receptors; temsirolimus (CCI-779), a kinase blocker that inhibits the mammalian target of rapamycin pathway; and erlotinib, an inhibitor of the tyrosine kinases associated with the EGF receptor, have shown promise. Combinations of the above therapies and cytokines also are being investigated, as there may be synergistic effects.

Biopsy↗
PubMed2006

Implementing cash for work programmes in post-tsunami Aceh: experiences and lessons learned.

Cash for work (CFW) programmes are utilised in various disaster and emergency contexts and were a prominent component of the tsunami response in Aceh province, Indonesia. This paper describes Mercy Corps' CFW programme, discusses CFW implementation experiences and provides key recommendations for similar programmes in future emergencies. For the majority of CFW participants and their households, CFW was the only source of household income and 93 per cent of household incomes were attributable to it. The CFW programme empowered displaced populations to return to their communities; 91 per cent of participants indicated that CFW facilitated their return. Other reported psychosocial benefits included providing productive activities and giving communities an opportunity to work together. Mercy Corps' experience in Aceh demonstrates that cash disbursements can be safely delivered in a widespread manner in emergencies, and that when implemented on a short-term basis, can have positive impacts at the individual and community level.

Disasters↗
PubMed2005

UVA-visible photo-excitation of guanine radical cations produces sugar radicals in DNA and model structures.

This work presents evidence that photo-excitation of guanine radical cations results in high yields of deoxyribose sugar radicals in DNA, guanine deoxyribonucleosides and deoxyribonucleotides. In dsDNA at low temperatures, formation of C1'* is observed from photo-excitation of G*+ in the 310-480 nm range with no C1'* formation observed > or =520 nm. Illumination of guanine radical cations in 2'dG, 3'-dGMP and 5'-dGMP in aqueous LiCl glasses at 143 K is found to result in remarkably high yields (approximately 85-95%) of sugar radicals, namely C1'*, C3'* and C5'*. The amount of each of the sugar radicals formed varies dramatically with compound structure and temperature of illumination. Radical assignments were confirmed using selective deuteration at C5' or C3' in 2'-dG and at C8 in all the guanine nucleosides/tides. Studies of the effect of temperature, pH, and wavelength of excitation provide important information about the mechanism of formation of these sugar radicals. Time-dependent density functional theory calculations verify that specific excited states in G*+ show considerable hole delocalization into the sugar structure, in accord with our proposed mechanism of action, namely deprotonation from the sugar moiety of the excited molecular radical cation.

Cations↗
PubMed2005

Heart failure observation units: optimizing care.

Heart failure causes substantial morbidity and mortality in the United States and accounts for a higher proportion of Medicare costs than any other disease. Most of these costs result from the high rate of hospital admissions and protracted length of stay associated with episodes of acute decompensation of heart failure. Thus, effective clinical strategies to obviate hospitalization and readmission can result in substantial savings. A specialized heart failure observation unit, in which patients receive rapid, goal-directed emergency care for heart failure symptoms, can be a critical component in this effort, providing intensive therapeutic monitoring and education. In institutions with specialized heart failure observation units, patients are triaged to this setting shortly after presentation to the emergency department (ED), and clinic referrals can be directed to this unit after minimal ED evaluation. Aggressive follow-up is also arranged at discharge. Recent additions to the therapeutic armamentarium and future advances in diagnostics and monitoring will continue to improve patient care and prevent avoidable hospitalizations.

Coronary Care Units↗
PubMedDate not supplied

Management of acute decompensated heart failure in the emergency department.

Heart failure, a disease of epidemic proportions, has a tremendous clinical and financial impact on the US health care system. With more than 5 million Americans diagnosed with heart failure and 5-year mortality approaching 50%, it is the most common cause of hospitalization in patients older than 65 years and is the single most expensive diagnosis in the US health care system. Because the average US hospital loses more than 1000 dollars per heart failure admission, effective therapies that decrease length of stay, reduce hospital costs, and prevent 30-day readmissions are needed. This article reviews the relevant pathophysiology of heart failure, discusses the newest diagnostic strategies for emergency department diagnoses, evaluates recent advances and effects of early aggressive therapies, and presents a suggested algorithm for the treatment of acutely decompensated heart failure in emergency departments.

Aged↗