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Abstract
Giant vesico-prostatic urethral calculus is uncommon. Urethral stones rarely form primarily in the urethra, and they are usually associated with urethral strictures, posterior urethral valve or diverticula. We report a case of a 32-year-old man with giant vesico-prostatic (collar-stud) urethral stone presenting with sepsis and bladder outlet obstruction. The clinical presentation, management, and outcome of the giant prostatic urethral calculus are reviewed.
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102
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Tonelli M, Wiebe N, Knoll G, Bello A, Browne S, Jadhav D, Klarenbach S, Gill J. Systematic review: kidney transplantation compared with dialysis in clinically relevant outcomes. Am J Transplant 2011; 11:2093-109. [PMID: 21883901 DOI: 10.1111/j.1600-6143.2011.03686.x] [Citation(s) in RCA: 864] [Impact Index Per Article: 66.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Individual studies indicate that kidney transplantation is associated with lower mortality and improved quality of life compared with chronic dialysis treatment. We did a systematic review to summarize the benefits of transplantation, aiming to identify characteristics associated with especially large or small relative benefit. Results were not pooled because of expected diversity inherent to observational studies. Risk of bias was assessed using the Downs and Black checklist and items related to time-to-event analysis techniques. MEDLINE and EMBASE were searched up to February 2010. Cohort studies comparing adult chronic dialysis patients with kidney transplantation recipients for clinical outcomes were selected. We identified 110 eligible studies with a total of 1 922 300 participants. Most studies found significantly lower mortality associated with transplantation, and the relative magnitude of the benefit seemed to increase over time (p < 0.001). Most studies also found that the risk of cardiovascular events was significantly reduced among transplant recipients. Quality of life was significantly and substantially better among transplant recipients. Despite increases in the age and comorbidity of contemporary transplant recipients, the relative benefits of transplantation seem to be increasing over time. These findings validate current attempts to increase the number of people worldwide that benefit from kidney transplantation.
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Tonelli M, Wiebe N, Knoll G, Bello A, Browne S, Jadhav D, Klarenbach S, Gill J. Systematic review: kidney transplantation compared with dialysis in clinically relevant outcomes. Am J Transplant 2011. [PMID: 21883901 DOI: 10.1111/j.1600-6143.2011.03686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Individual studies indicate that kidney transplantation is associated with lower mortality and improved quality of life compared with chronic dialysis treatment. We did a systematic review to summarize the benefits of transplantation, aiming to identify characteristics associated with especially large or small relative benefit. Results were not pooled because of expected diversity inherent to observational studies. Risk of bias was assessed using the Downs and Black checklist and items related to time-to-event analysis techniques. MEDLINE and EMBASE were searched up to February 2010. Cohort studies comparing adult chronic dialysis patients with kidney transplantation recipients for clinical outcomes were selected. We identified 110 eligible studies with a total of 1 922 300 participants. Most studies found significantly lower mortality associated with transplantation, and the relative magnitude of the benefit seemed to increase over time (p < 0.001). Most studies also found that the risk of cardiovascular events was significantly reduced among transplant recipients. Quality of life was significantly and substantially better among transplant recipients. Despite increases in the age and comorbidity of contemporary transplant recipients, the relative benefits of transplantation seem to be increasing over time. These findings validate current attempts to increase the number of people worldwide that benefit from kidney transplantation.
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104
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Li C, Alvey C, Bello A, Wilner KD, Tan W. Pharmacokinetics (PK) of crizotinib (PF-02341066) in patients with advanced non-small cell lung cancer (NSCLC) and other solid tumors. J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.15_suppl.e13065] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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105
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Ekman E, Gimbel J, Bello A, Smith M, Keller D, Annis K, Brown M, West C, Verburg K. Efficacy and safety of intravenous tanezumab in osteoarthritis hip and knee pain: comparison to placebo and naproxen in two phase III studies (NCT00830063 & NCT00863304). THE JOURNAL OF PAIN 2011. [DOI: 10.1016/j.jpain.2011.02.223] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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106
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Oguntayo OA, Zayyan M, Odogwu K, Koledade K, Mbibu H, Bello A, Sani S. Foreign body (Metallic flashlight cover) in the urinary bladder mimicking advanced cancer of the cervix: Case report and review of the literature. AFRICAN JOURNAL OF UROLOGY 2010. [DOI: 10.1007/s12301-009-0018-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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107
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Mathew J, Karia R, Warrich N, Morgan D, Lee A, Ellis I, Robertson J, Bello A. O-58 Factors influencing local control in patients undergoing breast conservation surgery for ductal carcinoma in situ. EJC Suppl 2010. [DOI: 10.1016/j.ejcsup.2010.06.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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108
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Ahmed A, Bello A, Mbibu NH, Maitama HY, Kalayi GD. Epidemiological and aetiological factors of male infertility in northern Nigeria. Niger J Clin Pract 2010; 13:205-209. [PMID: 20499757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
OBJECTIVE To evaluate some epidemiologic and aetiologic factors for male infertility in our patients. METHOD All male patients who presented with infertility in urology clinic of the department of surgery between 1991and2005 were retrospectively reviewed. Epidemiologic and aetiological factors of male infertility were studied. RESULT There were 537 patients; age ranged 18 to 56 years with a mean of 34 +/- 9.0 SD years. Primary infertility was seen in 515 (96%) patients. About 70% were infertile for 2 to 6 years. Primary testicular insufficiency was seen in 260 patients (48.7%) mainly resulting from genitourinary tract infection. Azoospermia resulting from testicular pathology was seen in 18 (3.4%) and obstruction to the vas or epididymis was seen 75 (14.0%) patients. Two hundred and fourteen (45%) patients had oligospermia resulting from testicular insufficiency while 61 (11.4%) had oligospermia due obstruction. CONCLUSION Infertility resulted mainly from preventable causes. This can be prevented by prompt and adequate treatment of genitourinary infection, testicular maldescent and testicular torsion.
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Yin D, Carpentieri M, Gualberto A, Li D, Paz-Ares LG, Canon JR, Sanchez-Torres J, O'Byrne KJ, Bello A. Effect of figitumumab (CP-751871) on the pharmacokinetics of cisplatin and pemetrexed in patients with advanced non-small cell lung cancer (NSCLC). J Clin Oncol 2010. [DOI: 10.1200/jco.2010.28.15_suppl.e18046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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110
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Xu H, Yin D, Pierce KJ, Shreeve SM, Duncan B, Bello A. Pharmacokinetics (PK) of PF-562271, a focal adhesion kinase (FAK) inhibitor, and its effect on CYP3A in patients with advanced nonhematologic malignancies. J Clin Oncol 2010. [DOI: 10.1200/jco.2010.28.15_suppl.2553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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111
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Laredo E, Grimau M, Bello A, Wu DF, Zhang YS, Lin DP. AC Conductivity of Selectively Located Carbon Nanotubes in Poly(ε-caprolactone)/Polylactide Blend Nanocomposites. Biomacromolecules 2010; 11:1339-47. [DOI: 10.1021/bm100135n] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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112
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Ogunbode O, Omololu O, Ogunbode A, Bello A. O700 Perceptions of Nigerian female undergraduates towards sexually coercive behaviours. Int J Gynaecol Obstet 2009. [DOI: 10.1016/s0020-7292(09)61073-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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113
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Yusuf AJ, Bello A, Abubakar ML, Mbibu NH. Genital self-mutilation in schizophrenic patients. A report of two cases. AFRICAN JOURNAL OF UROLOGY 2009. [DOI: 10.1007/s12301-009-0035-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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114
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Bello A, Tran K, Chand A, Doria M, Allocca M, Hildinger M, Beniac D, Kranendonk C, Auricchio A, Kobinger GP. Isolation and evaluation of novel adeno-associated virus sequences from porcine tissues. Gene Ther 2009; 16:1320-8. [PMID: 19626054 DOI: 10.1038/gt.2009.82] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
High antigenic compatibility and low toxicity is associated with xenograft transplantation of porcine tissues in immunodeficient human recipients. We hypothesized that adeno-associated viruses (AAVs) of porcine origin could be highly compatible to human tissues and thus of good efficiency and low toxicity for in vivo gene transfer. Porcine tissues were screened by PCR for the presence of AAV using primers designed to bind conserved regions and amplify variable regions of an alignment of several AAV sequences available on GenBank. We isolated new AAV capsid sequences from porcine tissues and successfully generated a recombinant AAV2/po1 vector by transfection. The AAV2/po1 vector was not cross-neutralized by antisera generated against all other commonly used AAVs (serotype 1, 2, 3, 4, 5, 7 and 8) indicating a distinct antigenic profile. Preexisting immunity to AAVpo1 could not be detected in the human sera evaluated. In mice, AAV2/po1 particles expressing beta-galactosidase or green fluorescent protein demonstrated high transduction efficiency in muscle fibers and the retina after intramuscular or intraocular administration. Biodistribution experiments following systemic administration showed efficient gene transfer exclusively in muscle fibers. Novel AAVs derived from porcine tissues may contribute to the generation of new preventive or curative clinical modalities acceptable for human use.
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Ahlgren P, Thirlwell M, O’Regan R, Mormont C, Levesque L, Gaspo R, Woloj M, Bello A, Martell B, Leyland-Jones B. An open-label study of sunitinib (SU) plus exemestane (E) in the first-line treatment of hormone receptor (HR)-positive metastatic breast cancer (MBC). J Clin Oncol 2009. [DOI: 10.1200/jco.2009.27.15_suppl.e12019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
e12019 Background: SU, an oral multitargeted tyrosine kinase inhibitor of VEGFRs, PDGFRs, KIT, FLT3, CSF-1R and RET has activity in heavily pretreated pts with MBC. The aromatase inhibitor (AI), E, has proven 1st-line activity that compares favorably with tamoxifen in pts with HR+ BC in the adjuvant setting (Jones et al. 2008). Combining agents that target different signaling pathways may have additive/synergistic activity; combining the AI letrozole with the anti-VEGF agent bevacizumab prolonged progression-free survival to >14 mos as 1st-line therapy for HR+ MBC (Dickler et al. 2008). An open-label, phase I, dose-finding study of first-line SU + E was conducted in HR+ MBC pts. Methods: Eligible pts (postmenopausal; female; ≥18 yrs) had an ECOG PS ≤1, LVEF ≥50% and locally recurrent (unresectable) or MBC. Exclusion criteria included HER2+ BC (unless pt had progressed after trastuzumab) and prior treatment in the metastatic setting. Pts received SU 37.5 mg/d + E 25 mg/d on a continuous daily dosing regimen; if dose-limiting toxicities (DLTs) were experienced by >1/6 pts in the first 8 wks then further pts would be enrolled at SU 25 mg/d + E 25 mg/d. Pharmacokinetic (PK) analyses were performed for each drug and the active SU metabolite SU12662. Results: As of December 2008, enrollment was completed (N=6; mean age 59 ± 11 yrs; 50% of pts had ≥3 metastatic sites). No DLTs were observed and no dose reductions were required throughout the treatment period. An overview of key data is shown below. One death occurred on study (non treatment-related Enterobacter sepsis). No treatment-related G4/5 AEs occurred. PK parameter values determined for SU and E suggested increases in the systemic exposure of both drugs when administered concurrently. Conclusions: These data indicate that SU + E was tolerable with manageable toxicities, with increases in PK parameters and a similar AE profile to that of either single agent alone. This combination should be considered in future clinical trials. [Table: see text] [Table: see text]
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Bello A, Dorantes S, Márquez JL, Jaimes ML. Physical and biochemical characteristics of platelets in severely malnourished children with purpura. SCANDINAVIAN JOURNAL OF HAEMATOLOGY 2009; 8:321-7. [PMID: 5134832 DOI: 10.1111/j.1600-0609.1971.tb00881.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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117
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Robertson L, Díez-Rojo MA, López-Pérez JA, Buena AP, Escuer M, Cepero JL, Martínez C, Bello A. New Host Races of Meloidogyne arenaria, M. incognita, and M. javanica from Horticultural Regions of Spain. PLANT DISEASE 2009; 93:180-184. [PMID: 30764107 DOI: 10.1094/pdis-93-2-0180] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In total, 140 populations of the genus Meloidogyne collected from representative horticultural regions of Spain and maintained at the Department of Agroecology, Institute of Agrarian Sciences, Madrid were characterized using perineal morphology, sequenced characterized amplified region polymerase chain reaction with species-specific primers, and bioassay. Using a modified North Carolina differential host test as a basis, 13 Meloidogyne populations did not fit into the published race scheme. These populations had very limited host ranges, reproducing only on susceptible tomato cv. Marmande and sometimes also on tobacco cv. NC95 and the pepper cv. Sonar in the case of Meloidogyne arenaria. They did not reproduce on cotton or peanut. The species and new races were identified as M. incognita races 5 (6 populations) and 6 (2 populations) and M. javanica race 5 (2 populations), with new records of M. arenaria race 3 (2 populations) and M. javanica race 1 (23 populations) for Spain.
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118
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Casali PG, Fumagalli E, Bello A, George S. Safety and tolerability of sunitinib (SU) initiated 24 h after the last dose of imatinib (IM) in advanced GIST. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.10557] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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119
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Chiorean EG, Sweeney CJ, Verschraegen CF, Lee FC, Jones SF, Rabinowitz I, Tye L, Bello A, Chao R, Burris HA. Tolerability/safety of sunitinib (SU) on schedule 2/1 in combination with capecitabine (C) in patients (pts) with advanced solid tumors (STs): A phase I dose-finding study. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.3562] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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120
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Riest G, Peters J, Weiss M, Dreyer S, Klassen PD, Stegen B, Bello A, Eikermann M. Preventive effects of perioperative parecoxib on post-discectomy pain. Br J Anaesth 2007; 100:256-62. [PMID: 18079431 DOI: 10.1093/bja/aem345] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Cyclooxygenase inhibitor treatment is viewed increasingly critical because of safety considerations, and there are several open questions on their optimal use. METHODS In a randomized placebo-controlled study in 320 patients undergoing discectomy, we administered parecoxib 40 mg either perioperatively (before operation and after operation), after operation (first dose given in the evening after surgery), or before operation (single parecoxib dose given 45 min before surgery). We measured the main outcome variables: average pain score, morphine consumption, and opioid-related symptom distress at 25, 49, and 73 h after surgery. RESULTS Perioperative parecoxib significantly (i) improved the pain score compared with both placebo and postoperative parecoxib, (ii) decreased morphine consumption, and (iii) reduced the opioid-related symptom distress score. Neither a single preoperative dose nor postoperative parecoxib (first dose given in the evening after surgery) significantly improved morphine's analgesic effectiveness. CONCLUSIONS Perioperative parecoxib compared with postoperative parecoxib improves post-discectomy pain and results in a reduction in adverse effects associated with opioid therapy. Postoperative parecoxib, or a single pre-incisional parecoxib dose, does not significantly improve post-discectomy pain or opioid side-effects up to 3 days after surgery.
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Cross J, Steinberg M, Yassi A, Astrakianakis G, Lu J, Rodriguez-Acosta RL, Schoenfisch AL, Richardson DB, Lipscomb HJ, Dement JM, Alamgir H, Yu S, Quinn MM, Markkanen P, Galligan C, Chalupka S, Kim H, Sama S, Gore R, Kriebel D, Bello A, Davis L, Laramie A, Firsova N. Health care workers. Occup Environ Med 2007. [DOI: 10.1136/oem.64.12.e6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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122
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Piedra Buena A, García-Alvarez A, Díez-Rojo MA, Ros C, Fernández P, Lacasa A, Bello A. Use of pepper crop residues for the control of root-knot nematodes. BIORESOURCE TECHNOLOGY 2007; 98:2846-51. [PMID: 17098424 DOI: 10.1016/j.biortech.2006.09.042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 09/27/2006] [Accepted: 09/27/2006] [Indexed: 05/12/2023]
Abstract
The biofumigant effect of pepper crop residues (PCR) for controlling Meloidogyne incognita populations was evaluated. Under laboratory conditions, 0, 5, 10 and 20 g PCR were applied to 500 g nematode infested soil, with four replicates per treatment. After 20 days at 25 degrees C, PCR reduced significantly M. incognita populations and root galling indices in susceptible tomato cv. Marmande, and increased K, N and organic C in soil. In the field, biofumigation with PCR combined with fresh animal manures (with and without plastic cover), methyl bromide, and a control were evaluated through root galling indices on a pepper crop. Each treatment, except for the control, had a grafted and non-grafted susceptible pepper sub-treatment, with three replicates. Root galling indices were lower, and yields higher, on grafted plants, biofumigation with PCR and plastic cover, with similar values as MB treatment, suggesting that biofumigation with PCR is an efficient non-chemical alternative to control M. incognita populations, especially when applied with plastic cover, nitrogen-rich organic matter and followed by grafting on resistant pepper.
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Verschraegen C, Sweeney C, Chiorean G, Lee F, Jones S, Tye L, Bello A, Chao R, Burris H. 714 POSTER Phase I tolerability/safety of sunitinib in combination with capecitabine in patients (pts) with advanced solid tumors. EJC Suppl 2007. [DOI: 10.1016/s1359-6349(07)70513-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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124
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Leong S, Eckhardt S, Chan E, Chow L, VerMeulen W, Rothenberg M, Bello A, Chow Maneval E, Chao R, Lockhart A. 716 POSTER Sunitinib combined with modified (m) FOLFOX6 chemotherapy in patients with advanced solid tumors: a phase I study. EJC Suppl 2007. [DOI: 10.1016/s1359-6349(07)70515-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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125
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Mehta V, Johnston A, Cheung R, Bello A, Langford RM. Intravenous Parecoxib Rapidly Leads to COX-2 Inhibitory Concentration of Valdecoxib in the Central Nervous System. Clin Pharmacol Ther 2007; 83:430-5. [PMID: 17687276 DOI: 10.1038/sj.clpt.6100304] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Evidence in animal studies supports widespread induction of cyclooxygenase-2 (COX-2) in the central nervous system (CNS) following tissue injury, probably mediated by cytokines, transducing the signal across the blood-brain barrier. CNS COX-2 blockade is a possible therapeutic target for drugs that are able to reach adequate CNS levels and abolish the prostaglandin E2-induced central sensitization. This human pharmacokinetic study investigated valdecoxib cerebrospinal fluid (CSF) and plasma concentrations over time in 37 patients following 40 mg of single-dose intravenous parecoxib. High-performance liquid chromatography/tandem mass spectrometry analysis was performed. Valdecoxib was first detectable in the CSF at 15 min postdosing, increased rapidly until 50 min, and thereafter remained between 6 and 14 ng/ml. This is the first human study demonstrating CNS COX-2 inhibitor penetration as early as 15 min. CSF valdecoxib concentration rapidly reached in vitro IC50 (inhibitory concentration 50) (1.57 ng/ml) by 17 min and remained consistently higher thereafter.
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Laredo E, Prutsky N, Bello A, Grimau M, Castillo RV, Müller AJ, Dubois P. Miscibility in poly(L-lactide)-b-poly(epsilon-caprolactone) double crystalline diblock copolymers. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2007; 23:295-303. [PMID: 17684703 DOI: 10.1140/epje/i2007-10191-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Accepted: 06/11/2007] [Indexed: 05/16/2023]
Abstract
Thermally stimulated depolarization currents, TSDC, wide-angle X-ray scattering, WAXS, differential scanning calorimetry, DSC, and polarized light optical microscopy, PLOM, have been used to examine poly(L-lactide)-b-poly(epsilon-caprolactone) diblock copolymers in a wide composition range. Both components are crystallizable and the miscibility in the amorphous phase has been determined from the behavior of the primary relaxations which are the dielectric manifestation of the glass transition, and also from the superstructural morphology revealed by PLOM and the compositional dependence of the melting points as determined by DSC. Distinct segmental mobilities in the amorphous phase which can be well resolved by TSDC are present; the alpha mode of the slower component shifts to lower temperatures as the PCL content increases while the glass transition of neat PCL is present for all compositions. A relaxation times bimodal distribution is apparent for PCL-rich copolymers. The composition dependence of the multiple glass transitions detected in these weakly segregated copolymers are predicted by the self-concentration model for a miscible blend made of components with a large T(g) contrast.
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Di Lorenzo L, Trabucco S, Massola A, Corfiati M, Bello A, Soleo L. [A case of occupational lung disease (welder lung) in a mechanical worker]. GIORNALE ITALIANO DI MEDICINA DEL LAVORO ED ERGONOMIA 2007; 29:840-843. [PMID: 18409991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A case of welder's lung is reported in a male hard smoker who had worked as welder-carpenter for almost 30 years. In order to establish an etiologic diagnosis, given the informed consent from the worker, open lung biopsy was performed that allowed to obtain sufficiently large specimens of affected lung to make histological, immunohistochemical and mineralogical examination. In such a way the pathologic features were accurately defined and a multidisciplinary approach was applied to differential diagnosis. The worker is recommended to undergo a strict health surveillance because of the reported association of welder's lung with lung cancer, especially in smokers.
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Sweeney C, Verschraegen C, Chiorean G, Lee F, Jones S, Tye L, Bello A, Chao R, Burris H. A phase I dose escalation study of sunitinib plus capecitabine in patients with advanced solid tumors. J Clin Oncol 2007. [DOI: 10.1200/jco.2007.25.18_suppl.3592] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
3592 Background: Sunitinib malate (SU) is an oral, multitargeted tyrosine kinase inhibitor of VEGFRs, PDGFRs, KIT, RET, and FLT3, approved internationally for the treatment of advanced RCC and imatinib-resistant or -intolerant GIST. This phase I study assesses the safety, tolerability and pharmacokinetics (PK) of SU in combination with capecitabine (C). Methods: Pts with advanced solid tumors not amenable to curative therapy, previously treated with =2 prior chemotherapy regimens, and ECOG PS =1 were eligible. Prior antiangiogenic therapy was not permitted. Three SU schedules were evaluated: 4 wks on treatment followed by 2 wks off in 6-wk cycles (4/2 schedule); 2 wks on followed by 1 wk off in 3-wk cycles (2/1 schedule), and continuous dosing (CD schedule). In all cases C was administered orally bid on days 1–14. SU and C doses were alternately escalated in serial pt cohorts to determine the maximum tolerated dose (MTD) of SU for all schedules using a standard 3 + 3 design. PK and antitumor efficacy were also assessed. Results: A total of 50 pts have been enrolled; 28 pts have been treated on the 4/2 schedule: SU 50 mg + C 1,000 mg/m2, and SU 37.5 mg + C 1,250 mg/m2 were not tolerated. Dose limiting toxicities (DLTs) included: grade 3 myalgia (n=1), grade 3 fatigue (n=2), and grade 3 hand- foot syndrome (n=2). The MTD for the 4/2 schedule was SU 37.5 mg/day + C 1,000 mg/m2. No DLTs nor dose reductions were observed among 9 pts treated at the MTD. Preliminary PK data do not indicate drug-drug interactions between SU and C. 3 pts (1 each with breast cancer, neuroendocrine carcinoma, and thyroid carcinoma) achieved confirmed partial responses. On the 2/1 schedule patients are being accrued to SU 37.5 or 50 mg + C 1,000 mg/m2 and doses of SU 37.5 mg + C 1,000 mg/m2 or SU 25 mg + C 1,250 mg/m2 are being explored on the CD schedule. Conclusions: The combination of SU 37.5 mg/day (4/2 schedule) with C 1,000 mg/m2 in pts with advanced solid tumors appears tolerable. SU may be administered in combination with C with no apparent drug-drug interaction. Subsequent cohorts will define the MTD of SU administered on the 2/1 and CD schedules. Further studies of this combination in breast cancer are warranted. No significant financial relationships to disclose.
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Bello A, Peteroy-Kelly MA. Research Note: The relationship between triclosan antimicrobial product usage and the susceptibility of the staphylococci to the antibiotic ciprofloxacin. ACTA ACUST UNITED AC 2007. [DOI: 10.1893/0005-3155(2007)78[51:rntrbt]2.0.co;2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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López-Cepero J, Piedra Buena A, Díez-Rojo MA, Regalado R, Brito E, Hernández Z, Figueredo M, Almendros G, Bello A. Evaluation of soil biodesinfestation with crop and garden residues in the control of root-knot nematodes populations. COMMUNICATIONS IN AGRICULTURAL AND APPLIED BIOLOGICAL SCIENCES 2007; 72:703-711. [PMID: 18399508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Fresh crop and garden residues were applied both under laboratory conditions and in commercial greenhouse in order to asses their effect on soil nematodes populations and soil fertility. In the laboratory experiments, dosages of 5 to 20 g of cabbage residues, chicken manure, cabbage residues+chicken manure, grass+chicken manure, as well as leaves and stems of orange tree, pine tree, oleander, olive tree, palm tree and boxwood were mixed with 500 g soil having root-knot nematodes (Meloidogyne incognita) and soil moisture was adjusted at field capacity. A control treatment without residues was also included. The mixtures were kept into plastic bags, with four replications, and the bags were incubated for four weeks at 30 degrees C, when nematological and soil fertility analyses were carried out. In general, all these materials significantly (P < 0.05) reduced M. incognita populations and increased saprophagous nematodes, with slight effects on soil fertility except for the K increase with residues application. Tomato plants susceptible to M. incognita were planted in pots with 300 cm3 of the treated soils and kept for five weeks in a growth chamber (24 +/- 1 degrees C, 14 hours light), when root galling indices were evaluated. Most materials applied reduced root galling indices as regards to the control. In the greenhouse experiment, cabbage residues, cabbage residues+chicken manure, grass+chicken manure and grass+cabbage residues were applied to the soil and covered with a polyethylene sheet for 5 weeks. A cabbage residues:chicken manure treatment and a control (not-amended) treatment, without polyethylene, were also included. At the end of the experiment, the nematological analysis showed that all materials successfully controlled M. incognita populations, reaching 86-100% mortality with organic amendments vs. 6% for the control. After the greenhouse biodesinfestation experiment, a tomato crop was grown for one month, when root galling indices were determined. All materials significantly reduced this value from 4.75 in the control to 1.0-2.25 with the organic amendments, except for the cabbage residues+chicken manure treatment without polyethylene (index = 4.0). Our results show that fresh crop and garden residues successfully reduced M. incognita populations and root galling indices when applied with polyethylene covers, having good potential to be considered in integrated management programs.
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Marco C, Bello A, Fatou JG. Thermal Stability of Poly(hexamethylene Oxide) Related to the Method of Synthesis. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/00222338008066640] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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132
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Di Lorenzo L, Pappagallo M, Gimigliano R, Palmieri E, Saviano E, Bello A, Forte A, DeBlasio E, Trombetti C. Pain relief in early rehabilitation of rotator cuff tendinitis: any role for indirect suprascapular nerve block? EUROPA MEDICOPHYSICA 2006; 42:195-204. [PMID: 17039215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
AIM The purpose of the trial was to evaluate the efficacy of suprascapular nerve block (SSNB) to relieve the shoulder pain, ameliorate recovery after physiotherapy and reduce disability due to a rotator cuff tendinitis (RCT). A prospective, randomized, comparison cross over investigation was performed in the setting of a large inpatient rehabilitation unit with more than 200 admissions annually. METHODS A total of 40 potential study subjects, who complained of shoulder pain from a RCT, were enrolled and randomly assigned to standard rehabilitation treatment plus SSNB (Group A) or to standard rehabilitation treatment alone (Group B). The UCLA shoulder rating scale was used to assess the shoulder mobility on admission and discharge, and to calculate the percentage of potential improvement achieved during rehabilitation (effectiveness). A pain visual analogic scale was used to serially assess pain. At the end of the trial, a self-report questionnaire evaluated whether patients could sleep and achieve activity of day life carry out everyday activities better than they could before treatment. RESULTS Forty patients suffering from RCT entered the study. Those receiving nerve block from the beginning of the treatment in addition to standard rehabilitation therapy reported significantly less pain during physiotherapy and better final outcomes. During treatment with SSNBs, patients reported a more significant reduction in the intensity of pain and a better reduction of pain during sleep and rehabilitation exercises in comparison to with the standard therapy alone. A statistically significant inverse correlation was found between shoulder pain and mobility. CONCLUSIONS The results indicate that combining nerve block with standard rehabilitative therapy may improve the final outcome of painful RCT. It decreased the severity and frequency of the perceived pain, improved the compliance with physiotherapy, restored more normal sleep patterns, and increased compliance with the rehabilitation program. This result proves to be an effective, safe and inexpensive therapeutic option for patients suffering from painful disabling shoulder tendinitis.
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Bello A, Giannetto M, Mori G. Electrochemically induced derivatization of poly(2,2′-bithiophene) and characterization of functionalized polymers by FT-IR microscopy, SEM microanalysis and EQCM. J Electroanal Chem (Lausanne) 2005. [DOI: 10.1016/j.jelechem.2004.09.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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134
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Laredo E, Grimau M, Bello A, Sánchez F, Gómez MA, Marco C, Campoy I, Arribas JM. The effect of compatibilization on the dynamic properties of polypropylene/nylon-6 blends studied by broad band dielectric spectroscopy. ACTA ACUST UNITED AC 2005. [DOI: 10.1002/polb.20421] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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135
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Grimau M, Laredo E, Sánchez F, López-Carrasquero F, Báez ME, Bello A. Molecular dynamics in nanophase-separated comb-like poly(alpha-n-alkyl beta-L-aspartate)s. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2004; 15:383-393. [PMID: 15565501 DOI: 10.1140/epje/i2004-10056-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2004] [Accepted: 10/04/2004] [Indexed: 05/24/2023]
Abstract
A series of poly(alpha-n-alkyl beta-L-aspartates) which are nanophase self-assembled comb-like polymers has been studied by dielectric spectroscopy in a broad frequency range (10(-2) < or = nu < or = 3 x 10(6) Hz), with n-alkyls side chains of various lengths, 10 < or = n < or =18. In every member of the series the same relaxations were identified after the decomposition of the experimental isothermal trace in up to three peaks with relaxation times distributions. The strength, width and average relaxation time for all the relaxation modes were determined for each material. Besides the local low temperature, Arrhenius modes, two relaxation modes, alpha and alpha(PE), present a cooperative character whose dynamics are not affected by the side chains melting. The alpha(PE) relaxation is a polyethylene-like glass transition of the amorphous side chains and its dynamics is strongly dependent on the n value due to the increasing restrictions imposed by the self-assembled confinement. The strength of the alpha(PE) relaxation mode increases as the lateral chains loose their 2D order. The restricted chopstick motion of the rigid rods is thought to be the origin of the alpha mode; this motion is hindered at temperatures where the cage size decreases as a result of the increasing disorder with temperature.
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Bello A, Capirci O, Volterra V. Lexical production in children with Williams syndrome: spontaneous use of gesture in a naming task. Neuropsychologia 2004; 42:201-13. [PMID: 14644106 DOI: 10.1016/s0028-3932(03)00172-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study investigates lexical organization and lexical retrieval in children with Williams syndrome (WS), by examining both naming accuracy and accompanying use of gestures in a picture-naming task. Ten children with the genetic disorder of Williams syndrome (age range: 9.5-12.9) were compared with 20 typically developing children, 10 matched for chronological age (CA) and 10 for mental-age (MA). Lexical production was measured by administering the Boston Naming test (BNT). Older typically developing children performed significantly better than the other two groups. No differences in accuracy were found between the children with WS and the typically developing children matched for mental-age. The overall distribution of error types displayed by children with WS indicate that the lexical-semantic organization is similar to that of typically developing children. However, compared to controls, the WS group produced more iconic gestures during the task, in patterns that suggest the existence of specific word-finding difficulties in these children. Results are discussed within the framework of recent theories on the role of gesture in speech production.
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Laredo E, Grimau M, Sánchez F, Bello A. Water Absorption Effect on the Dynamic Properties of Nylon-6 by Dielectric Spectroscopy. Macromolecules 2003. [DOI: 10.1021/ma034954w] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Gajjar DA, Bello A, Ge Z, Christopher L, Grasela DM. Multiple-dose safety and pharmacokinetics of oral garenoxacin in healthy subjects. Antimicrob Agents Chemother 2003; 47:2256-63. [PMID: 12821477 PMCID: PMC161848 DOI: 10.1128/aac.47.7.2256-2263.2003] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Garenoxacin (T-3811ME, BMS-284756) is a novel des-F(6) quinolone that has been shown to be effective in vitro against a wide range of clinically important pathogens, including gram-positive and gram-negative aerobes and anaerobes. This study was conducted to evaluate the safety and tolerability of multiple oral doses (100 to 1200 mg/day) of garenoxacin in healthy subjects and to determine its multiple-dose pharmacokinetics. Forty healthy male and female subjects (18 to 45 years of age) were enrolled in this randomized, double-blind, placebo-controlled, sequential, multiple- and ascending-dose study. Each subject received a once-daily oral dose of garenoxacin (100, 200, 400, 800, or 1200 mg) or a placebo for 14 days. Blood and urine samples were collected for measurements of garenoxacin by validated liquid chromatography with dual mass spectrometry, and plasma garenoxacin concentration-time data were analyzed by noncompartmental methods. The effects of garenoxacin on Helicobacter pylori, psychometric test performance, and electrocardiograms were assessed, as was drug safety. Over the 14 days of dosing, geometric mean peak concentrations of garenoxacin in plasma (C(max)) at the 100- and 1200-mg doses were within the ranges of 1.2 to 1.6 and 16.3 to 24 microg/ml, respectively. The corresponding values for the geometric mean area under the concentration-time curve over the dosing interval (AUC(tau)) for garenoxacin in plasma at the 100- and 1200-mg doses were within the ranges of 11.5 to 15.7 and 180 to 307 microg. h/ml, respectively. Increases in systemic exposure to garenoxacin in terms of AUC and C(max) were approximately dose proportional over the 100- to 400-mg dose range but demonstrated increases that were somewhat greater than the dose increments at the 800- and 1200-mg doses. Median values for the time to achieve C(max) were in the range of 1.13 to 2.50 h for all doses. The mean elimination half-life for garenoxacin in plasma appeared to be independent of dose and ranged from 13.3 to 17.8 h (day 14). Approximately 30 to 50% of an administered garenoxacin dose was excreted unchanged in the urine. At doses of 100 to 400 mg, steady-state concentrations of garenoxacin in plasma appeared to be attained by the fourth dose. Multiple oral doses of garenoxacin were well tolerated and did not demonstrate clinically significant effects on QT(c) or psychometric test results. Garenoxacin administered alone for 14 days at doses of >or=400 mg demonstrated activity against H. pylori. These results suggest that multiple once-daily oral doses of garenoxacin of up to 1200 mg are safe and well tolerated and that the pharmacokinetics of garenoxacin support once-daily administration.
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Nord CE, Meurling L, Russo RL, Bello A, Grasela DM, Gajjar DA. Effect of garenoxacin on eubacteria in the normal intestinal microflora when administered concomitantly with digoxin. J Chemother 2003; 15:244-7. [PMID: 12868550 DOI: 10.1179/joc.2003.15.3.244] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Garenoxacin is a new des-F(6)-quinolone with a broad antimicrobial spectrum. It has been reported that antibiotics may raise digoxin concentrations in the plasma of patients who are taking these agents concurrently, possibly due to the effect on the digoxin-metabolizing intestinal microflora. Sixteen healthy subjects were given a loading dose of digoxin (0.25 mg orally, q 6 h) on Day 1 followed by once-daily doses of 0.25 mg on Days 2 through 14. The subjects also received garenoxacin 600 mg orally, q 24 h, on Days 8 through 14. The number of enterococci, bacilli, corynebacteria, enterobacteria, bifidobacteria, lactobacilli, clostridia and bacteroides decreased whereas the number of eubacteria increased in the intestinal microflora. Eubacterium lentum strains increased during the administration of garenoxacin and returned towards normal levels within 14 days after the last dose of garenoxacin. The fecal concentrations of garenoxacin varied between 14.0-310.0 mg/kg. The minimum inhibitory concentrations of garenoxacin against the isolated E. lentum strains were >64 mg/L. There was no degradation of digoxin by the E. lentum strains.
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Andrews J, Honeybourne D, Jevons G, Boyce M, Wise R, Bello A, Gajjar D. Concentrations of garenoxacin in plasma, bronchial mucosa, alveolar macrophages and epithelial lining fluid following a single oral 600 mg dose in healthy adult subjects. J Antimicrob Chemother 2003; 51:727-30. [PMID: 12615879 DOI: 10.1093/jac/dkg110] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A microbiological assay was used to measure concentrations of garenoxacin (BMS-284756) in plasma, bronchial mucosa (BM), alveolar macrophages (AM) and epithelial lining fluid (ELF), following a single 600 mg oral dose. Twenty-four healthy subjects were allocated into four nominal time intervals after the dose, 2.5-3.5, 4.5-5.5, 10.5-11.5 and 23.5-24.5 h. Mean concentrations in plasma, BM, AM and ELF, respectively, for the four nominal time windows were for 2.5-3.5 h 10.0 mg/L (S.D. 2.8), 7.0 mg/kg (S.D. 1.3), 106.1 mg/L (S.D. 60.3) and 9.2 mg/L (S.D. 3.6); 4.5-5.5 h 8.7 mg/L (S.D. 2.2), 6.0 mg/kg (S.D. 1.9), 158.6 mg/L (S.D. 137.4) and 14.3 mg/L (S.D. 8.2); 10.5-11.5 h 6.1 mg/L (S.D. 1.9), 4.0 mg/kg (S.D. 1.4), 76.0 mg/L (S.D. 47.7) and 7.9 mg/L (S.D. 4.6); and 23.5-24.5 h 2.1 mg/L (S.D. 0.5), 1.7 mg/kg (S.D. 0.7), 30.7 mg/L (S.D. 12.9) and 3.3 mg/L (S.D. 2.3). Concentrations at all sites exceeded MIC(90)s for the common respiratory pathogens Haemophilus influenzae (0.03 mg/L), Moraxella catarrhalis (0.015 mg/L) and Streptococcus pneumoniae (0.06 mg/L). These data suggest that garenoxacin should be effective in the treatment of community-acquired pneumonia and chronic obstructive pulmonary disease.
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Noveck RJ, Vargas R, Russo R, Bello A, Gajjar D, Grasela D. Pharmacokinetics (PK) of Garenoxacin in Healthy Subjects and in Subjects With Hepatic Impairment. Clin Pharmacol Ther 2003. [DOI: 10.1016/s0009-9236(03)90650-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Herasme L, Bello A, Moreno L, Moya M, Rosario S. Country watch: Dominican Republic. AIDS HEALTH PROMOTION EXCHANGE 2002:9-11. [PMID: 12344820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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143
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Bello A, Perez E, Marugan MM, Perena JM. Liquid-crystalline poly[oxybis(trimethylene) p,p'-bibenzoate]: effect of the central ether group. Macromolecules 2002. [DOI: 10.1021/ma00205a037] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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145
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Bello A, Bracke W, Jagur-Grodzinski J, Sackmann G, Szwarc M. Poly(hexamethylphosphoramide) and Its Copolymer. Macromolecules 2002. [DOI: 10.1021/ma60013a021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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146
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Marco C, Bello A, Perena JM, Fatou JG. Oxidation of poly(hexamethylene sulfide) single crystals. Macromolecules 2002. [DOI: 10.1021/ma00235a019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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147
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Gomez MA, Cozine MH, Schilling FC, Tonelli AE, Bello A, Fatou JG. Solid-state carbon-13 NMR study of poly(3,3-diethyloxetane). Macromolecules 2002. [DOI: 10.1021/ma00174a008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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148
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Laredo E, Hernandez MC, Bello A, Grimau M, Müller AJ, Balsamo V. Local and segmental dynamics in homopolymer and triblock copolymers with one semicrystalline block. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2002; 65:021807. [PMID: 11863555 DOI: 10.1103/physreve.65.021807] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2001] [Indexed: 05/23/2023]
Abstract
Thermally stimulated depolarization currents, TSDC, experiments have been performed on a series of poly(styrene)-b-poly(butadiene)-b-poly(epsilon-caprolactone) triblock copolymers SBC with different proportions of the poly(epsilon-caprolactone) crystallizable block, PCL. The morphology of the segregated microphases varies with the PCL content and has been observed by transmission electron microscopy. The crystallinity of the PCL block is estimated by wide angle x-ray scattering, WAXS. The relaxation times distribution is extracted by a numerical decomposition of the TSDC spectra and it is shown that this distribution is not significantly changed on going from the homopolymer to the triblock copolymer with 16 wt % to 77 wt % of PCL in the original samples. Better segregation of the mesophase structure is reached when the samples are annealed at 413 K and important variations in the TSDC and WAXS spectra are observed as a result of the thermal treatment. For the S09B14C77 triblock copolymer the results obtained can be explained by postulating the existence of a rigid amorphous phase in the PCL block. Such rigid amorphous phase is located between the core-shell cylinders formed by the other blocks [with poly(styrene)(PS) as core and poly(butadiene)(PB) as shell] and is constrained by undulated lamellae of crystalline PCL material. In the case of S35B15C50 triblock copolymer, an important amount of diffuse PS-PCL interphase where the homopolymers are mixed must be present before annealing. The results for the material with the less abundant PCL block are explained as a result of the confinement in nanotubes of PCL surrounded by PB embedded in a vitreous PS matrix. Broadband dielectric experiments on these same materials confirm the results obtained by TSDC spectroscopy.
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Grimau M, Laredo E, Pérez Y. MC, Bello A. Study of dielectric relaxation modes in poly(ε-caprolactone): Molecular weight, water sorption, and merging effects. J Chem Phys 2001. [DOI: 10.1063/1.1355288] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Puma M, Laredo E, Bello A, Galavis ME, Suarez N. Computer analysis of electron paramagnetic resonance data using the Monte Carlo method. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/21/32/010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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