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1.
Am J Transplant ; 16(2): 535-40, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26523479

RESUMO

Recipients of pancreas transplant alone (PTA) may be at increased risk for developing end-stage renal disease (ESRD). The survival experience of PTA recipients developing ESRD has not been described. Furthermore, the relative survival of these patients as compared to diabetics on chronic dialysis is unknown. We studied all adult PTA recipients from January 1, 1990 to September 1, 2008 using the Scientific Registry of Transplant Recipients. Each PTA recipient developing ESRD was matched to 10 diabetics on chronic dialysis from the United States Renal Data System. Cox proportional hazards models were fitted to determine the relation between ESRD and mortality among PTA recipients, and the relation between PTA and mortality among diabetics on chronic dialysis. There were 1597 PTA recipients in the study, of which 207 developed ESRD. Those with ESRD had a threefold increase in mortality versus those without (adjusted hazard ratio 3.28 [95% confidence interval: 2.27, 4.76]). There was no significant difference in the risk of death among PTA recipients with ESRD versus diabetics on dialysis. PTA recipients developing ESRD are three times more likely to die than PTA recipients without ESRD; however, the risk of death in these patients was similar to diabetics on chronic dialysis without PTA.


Assuntos
Diabetes Mellitus Tipo 1/terapia , Rejeição de Enxerto/etiologia , Falência Renal Crônica/etiologia , Transplante de Pâncreas/efeitos adversos , Adulto , Feminino , Seguimentos , Taxa de Filtração Glomerular , Sobrevivência de Enxerto , Humanos , Falência Renal Crônica/patologia , Testes de Função Renal , Masculino , Complicações Pós-Operatórias , Prognóstico , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Fatores de Risco
2.
Am J Transplant ; 11(9): 1792-802, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21812920

RESUMO

The first Banff proposal for the diagnosis of pancreas rejection (Am J Transplant 2008; 8: 237) dealt primarily with the diagnosis of acute T-cell-mediated rejection (ACMR), while only tentatively addressing issues pertaining to antibody-mediated rejection (AMR). This document presents comprehensive guidelines for the diagnosis of AMR, first proposed at the 10th Banff Conference on Allograft Pathology and refined by a broad-based multidisciplinary panel. Pancreatic AMR is best identified by a combination of serological and immunohistopathological findings consisting of (i) identification of circulating donor-specific antibodies, and histopathological data including (ii) morphological evidence of microvascular tissue injury and (iii) C4d staining in interacinar capillaries. Acute AMR is diagnosed conclusively if these three elements are present, whereas a diagnosis of suspicious for AMR is rendered if only two elements are identified. The identification of only one diagnostic element is not sufficient for the diagnosis of AMR but should prompt heightened clinical vigilance. AMR and ACMR may coexist, and should be recognized and graded independently. This proposal is based on our current knowledge of the pathogenesis of pancreas rejection and currently available tools for diagnosis. A systematized clinicopathological approach to AMR is essential for the development and assessment of much needed therapeutic interventions.


Assuntos
Autoanticorpos/imunologia , Rejeição de Enxerto/diagnóstico , Transplante de Pâncreas/imunologia , Guias de Prática Clínica como Assunto , Rejeição de Enxerto/imunologia , Humanos
3.
Am J Transplant ; 10(6): 1414-9, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20553448

RESUMO

Ureteral stricture is the most common urologic complication after renal transplantation. When endourologic management fails, open ureteral reconstruction remains the standard treatment. The complexity of some of these procedures makes it necessary to explore other means of repair. This study evaluated the intermediate-term outcome of subcutaneous pyelovesical bypass graft (SPBG) on renal transplant recipients. We reviewed 8 patients (6 male and 2 female; mean age 52 years) with refractory ureteral strictures postrenal transplantation, who received SPBG as salvage therapy. All patients failed endourologic management and half failed open management of their strictures. After a mean follow-up of 19.4 months, 7 out of 8 renal grafts have good function with mean GFR of 58.5 mL/min/1.73 m(2), without evidence of obstruction or infection. One patient lost his graft due to persistent infection of the SPBG and one patient developed a recurrent urinary tract infection managed with long-term antibiotics. SPBG offers a last resort in the treatment of ureteral stricture after renal transplantation refractory to conventional therapy.


Assuntos
Transplante de Rim/efeitos adversos , Ureter/cirurgia , Obstrução Ureteral , Adulto , Idoso , Constrição Patológica/complicações , Constrição Patológica/etiologia , Constrição Patológica/cirurgia , Feminino , Seguimentos , Humanos , Rim/cirurgia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento , Obstrução Ureteral/etiologia , Obstrução Ureteral/cirurgia , Obstrução Ureteral/terapia , Procedimentos Cirúrgicos Vasculares/efeitos adversos
4.
Transplant Proc ; 41(1): 133-4, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19249497

RESUMO

INTRODUCTION: The use of expanded criteria donors (ECDs) is still limited because of inferior graft survival compared to standard criteria donors (SCDs). We assessed the impact of immediate graft function (IGF) on renal graft survival among recipients of SCD and ECD grafts to determine whether these kidneys performed equally well under "ideal" conditions favoring IGF. METHODS: We included all cadaveric renal transplants performed from 1990 to 2002 (n = 335). Delayed graft function (DGF) was defined as the need for dialysis in the first 7 days posttransplant. Slow graft function (SGF) and IGF were defined as a serum creatinine fall by <20% versus >20% in the first 24 hours posttransplant, respectively. Non-death censored actual graft survivals are reported herein. RESULTS: Seventy-two of the 335 subjects (21.5%) received organs from ECDs and displayed IGF in 54.7%, SGF 16.2%, and DGF 29.1%. Among SCDs, the SGF and DGF rates were 15.3% and 23.4%, respectively. In ECD, the SGF and DGF rates were 19.4% and 50% (P < .02). Actual graft survivals at 1 and 5 years was 86.3% and 70.4%, respectively. Patients with IGF had higher actual graft survival at 5 years compared to SGF and DGF (83.5% vs 74.1% vs 45.4%). DGF had an equally bad impact on actual 5-year graft survival in SCDs and ECDs (42.6% vs 50%). CONCLUSION: DGF has a strong detrimental impact on 5-year graft survival. There is a higher rate of DGF in ECD versus SCD kidneys. The detrimental impact on 5-year actual graft survival is equal in SCD and ECD kidneys. Minimizing DGF should be our goal.


Assuntos
Sobrevivência de Enxerto/fisiologia , Transplante de Rim/fisiologia , Cadáver , Creatinina/sangue , Quimioterapia Combinada , Seguimentos , Rejeição de Enxerto/epidemiologia , Humanos , Imunossupressores/uso terapêutico , Transplante de Rim/imunologia , Seleção de Pacientes , Estudos Retrospectivos , Fatores de Tempo , Doadores de Tecidos
5.
Transplant Proc ; 41(1): 124-6, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19249494

RESUMO

INTRODUCTION: Because kidneys show remarkable resilience and can recover function, we examined the impact on long-term graft survival in deceased donor renal transplants of both immediate graft function (IGF) and the rate of renal function recovery over the first 3 months after transplantation. METHODS: We included all cadaveric renal transplants from 1990 to 2007 (n = 583). Delayed graft function (DGF) was defined as the need for dialysis in the first 7 days posttransplant. Slow graft function (SGF) and IGF were defined by serum creatinine falls of <20% or >20% in the first 24 hours posttransplant respectively. Recovery of renal function was expressed as either the best creatinine clearance (CrCl) in the first 3 months post-renal transplantation (BCrCl-3mos) as calculated using the Cockcroft-Gault formula or as a percentage of actual versus expected value (as calculated from the donors' CrCl at procurement). RESULTS: There were 140 (23.6%) subjects who received extended criteria donor (ECD) organs. The overall graft survival at 1 and 5 years was 87.8% and 74%, respectively. The 5-year graft survivals for patients with IGF, SGF, and DGF were 85%, 76%, and 54%, respectively (P < .02). ECD kidneys showed twice the DGF rate (49% vs 23%, P < .001). BCrCl-3mos of <30 mL/min displayed a 5-year graft survival of 34%; 30 to 39 mL/min, 72%; 40 to 49 mL/min, 85%; and >50 mL/min, 82% (P < .001). Similarly, a recovery within 90% of expected CrCl in the first 3 months posttransplant correlated with 5-year graft survival of 81%; a recovery of 70% to 90%, with 65%; and a recovery of <70%, with 51% (P < .001). CONCLUSION: Early graft function in the first 3 months showed a significant impact on long-term graft survival after deceased donor renal transplantation.


Assuntos
Cadáver , Sobrevivência de Enxerto/fisiologia , Transplante de Rim/fisiologia , Doadores de Tecidos , Creatinina/metabolismo , Seguimentos , Humanos , Testes de Função Renal , Transplante de Rim/mortalidade , Seleção de Pacientes , Taxa de Sobrevida , Sobreviventes , Fatores de Tempo
6.
Am J Transplant ; 8(2): 307-16, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18211506

RESUMO

In a randomized, open-label, multicenter study, de novo renal transplant patients received no steroids (n = 112), steroids to day 7 (n = 115), or standard steroids (n = 109) with cyclosporine microemulsion (CsA-ME), enteric-coated mycophenolate sodium (EC-MPS) and basiliximab. The primary objective, to demonstrate noninferiority of 12-month GFR in the steroid-free or steroid-withdrawal groups versus standard steroids, was not met in the intent-to-treat population. However, investigational groups were not inferior to standard steroids in the observed-case analysis. Median 12-month GFR was not significantly different in the steroid-free or steroid-withdrawal groups (58.6 mL/min/1.73 m(2) and 59.1 mL/min/1.73 m(2)) versus standard steroids (60.8 mL/min/1.73 m(2)). The 12-month incidence of biopsy-proven acute rejection (BPAR), graft loss or death was 36.0% in the steroid-free group (p = 0.007 vs. standard steroids), 29.6% with steroid withdrawal (N.S.) and 19.3% with standard steroids. BPAR was significantly less frequent with standard steroids than either of the other two regimens. Reduced de novo use of antidiabetic and lipid-lowering medication, triglycerides and weight gain were observed in one or both steroid-minimization group versus standard steroids. For standard-risk renal transplant patients receiving CsA-ME, EC-MPS and basiliximab, steroid withdrawal by the end of week 1 achieves similar 1-year renal function to a standard-steroids regimen, and may be more desirable than complete steroid avoidance.


Assuntos
Corticosteroides/uso terapêutico , Imunossupressores/uso terapêutico , Transplante de Rim/fisiologia , Metilprednisolona/uso terapêutico , Adolescente , Corticosteroides/administração & dosagem , Corticosteroides/efeitos adversos , Adulto , Idoso , Esquema de Medicação , Quimioterapia Combinada , Seguimentos , Taxa de Filtração Glomerular , Teste de Histocompatibilidade , Humanos , Imunossupressores/efeitos adversos , Transplante de Rim/imunologia , Metilprednisolona/administração & dosagem , Metilprednisolona/efeitos adversos , Pessoa de Meia-Idade , Doadores de Tecidos/estatística & dados numéricos
7.
Int J Dent Hyg ; 6(4): 280-9, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19138179

RESUMO

OBJECTIVE: To review the literature on whether a hand-held triangular woodstick, as compared with no adjunct or other interdental cleaning device in addition to daily toothbrushing, can improve clinical parameters of gingival inflammation. MATERIAL AND METHODS: MEDLINE and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched through February 2008 to identify appropriate studies. Plaque and gingivitis were selected as outcome variables. RESULTS: Independent screening of the titles and abstracts of 181 MEDLINE and 65 CENTRAL papers yielded seven publications with eight clinical experiments that met the eligibility criteria. The improvement in gingival health, as observed in seven studies, represents a significant incremental benefit realized by the use of triangular woodsticks. None of the studies that scored plaque demonstrated any significant advantage to the use of woodsticks, as opposed to alternative methods, in gingivitis patients. CONCLUSION: Evidence from controlled trials, most of which were also randomized, shows that woodsticks do not have an additional effect on visible interdental plaque or gingival index, but do, however, provide an improvement in interdental gingival inflammation by reducing the bleeding tendency.


Assuntos
Dispositivos para o Cuidado Bucal Domiciliar/classificação , Placa Dentária/prevenção & controle , Gengivite/prevenção & controle , Índice de Placa Dentária , Hemorragia Gengival/prevenção & controle , Humanos , Índice Periodontal , Ensaios Clínicos Controlados Aleatórios como Assunto , Projetos de Pesquisa
8.
Int J Dent Hyg ; 6(3): 154-65, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18768018

RESUMO

AIM: To review the available literature, considering the effect of instrumentation with the Vector ultrasonic scaler on human teeth in vitro and in vivo compared to conventional ultrasonic instruments and/or hand instrumentation. The assessed effects are calculus removal, time of instrumentation, root surface aspects, cell attachment, patients' perception, bleeding upon probing, pocket depth, clinical attachment loss and microbiological effects. MATERIALS AND METHODS: MEDLINE-PubMed and the Cochrane Central register of controlled trials (CENTRAL) were searched up through January 2008 to identify appropriate studies. RESULTS: Independent screening of the titles and abstracts of 270 MEDLINE-PubMed and 15 Cochrane papers resulted in 15 suitable publications. The studies differed in design and outcome, so this review summarizes the outcomes in a descriptive manner. Comparisons are presented against conventional ultrasonic system and scaling and root planing. CONCLUSION: The Vector ultrasonic scaler provided comparable clinical and microbiological periodontal healing results as scaling and root planing and conventional ultrasonic system in moderately deep pockets. The Vector ultrasonic scaler may be used as a gentle root debridement device for supportive periodontal therapy, as an alternative to other conventional ultrasonic system. The operator should however consider the extra time needed for instrumentation.


Assuntos
Raspagem Dentária/instrumentação , Dente/patologia , Terapia por Ultrassom/instrumentação , Cálculos Dentários/terapia , Desenho de Equipamento , Humanos , Satisfação do Paciente , Doenças Periodontais/terapia , Fatores de Tempo , Raiz Dentária/patologia
9.
J Periodontol ; 78(6): 1011-6, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17539713

RESUMO

BACKGROUND: Inconclusive evidence exists in the literature with regard to the additional (beneficial) mechanical effect of a dentifrice on plaque removal. A previous split-mouth study found that a dentifrice did not contribute to plaque removal. Because of limitations of the split-mouth model, a crossover design was used to evaluate whether a commercially available dentifrice had an additional effect on mechanical plaque removal during manual toothbrushing. METHODS: Thirty-six subjects were given a manual toothbrush and a standard dentifrice. After a 48-hour plaque accumulation, subjects brushed under supervision with or without a dentifrice (total time of 2 minutes) in a 2 x 2 crossover design. RESULTS: Plaque reductions were 50% with and 56% without the use of dentifrice. This 6% difference was statistically significant (P = 0.034). Explorative analysis showed that brushing without a dentifrice was more effective in removing plaque on the approximal surfaces. CONCLUSIONS: The use of a dentifrice did not contribute to mechanical plaque removal during manual toothbrushing. It seemed that the mechanical action provided by the toothbrush was the main factor in the plaque-removing process.


Assuntos
Placa Dentária/terapia , Dentifrícios/uso terapêutico , Escovação Dentária/métodos , Adulto , Cariostáticos/uso terapêutico , Estudos Cross-Over , Dentifrícios/química , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Fluoreto de Sódio/uso terapêutico
10.
Oral Health Prev Dent ; 5(2): 145-52, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17722442

RESUMO

PURPOSE: To review in a systematic approach the effectiveness of specific fluoride treatments on the root caries activity in adults. MATERIALS AND METHODS: An electronic search of the National Library of Medicine, Washington DC (Medline-PubMed), and the specialist trials register of the Cochrane Oral Health Group up to and including April 2005 was performed using specific search terms to identify randomised controlled trials, controlled clinical trials and longitudinal studies of at least 3 months duration, which investigated the effect of specific fluoride treatments with regard to root caries activity and/or incidence in healthy adults. Comparisons were made against the root caries status before the initiation of the additional fluoride application regimen and between groups in controlled studies. The papers were screened independently by two reviewers (MH and SP). RESULTS: Out of 348 titles and abstracts, six papers fulfilled the selection criteria and were processed for data extraction. The highest level of evidence was presented in the two papers using a double-blind controlled randomised clinical trial (Wallace et al, 1993; Baysan et al, 2001). Both these studies indicate that the increased application of fluoride in the form of a high concentration dentifrice or additional mouthwash had a positive effect on the root caries incidence/severity. CONCLUSION: Additional fluoride appears to be a preventive and therapeutic treatment for root caries.


Assuntos
Cariostáticos/uso terapêutico , Fluoretos/uso terapêutico , Cárie Radicular/tratamento farmacológico , Adulto , Dentifrícios/química , Dentifrícios/uso terapêutico , Humanos , Antissépticos Bucais/química , Antissépticos Bucais/uso terapêutico , Cárie Radicular/epidemiologia , Desmineralização do Dente/tratamento farmacológico , Remineralização Dentária/métodos
11.
J Periodontol ; 77(9): 1522-7, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16945029

RESUMO

BACKGROUND: Inconclusive evidence exists in the literature with regard to the additional effect of the use of dentifrice on plaque removal. The present study was undertaken to test whether the use of dentifrice during toothbrushing contributes to the instant cleaning efficacy of the brushing procedure. METHODS: Three groups of patients, 40 subjects each, were randomly assigned to one of three dentifrices that differed with respect to the relative dentin abrasivity (RDA) value. After a 48-hour plaque accumulation, subjects brushed under supervision in a split-mouth order with or without the use of dentifrice (total time=2 minutes). RESULTS: Plaque reductions varied between 51% and 58% for the three dentifrices. The overall analysis showed a mean difference of 3% in plaque reduction in favor of brushing without dentifrice (P=0.017). The type of dentifrice did not influence this observed difference (P=0.506). Also, the order of the brushing procedure (starting the brushing procedure with or without dentifrice) had no interaction with the effect of dentifrice on the brushing (P=0.187). CONCLUSIONS: The use of dentifrice does not contribute to the instant mechanical plaque removal during manual toothbrushing. A higher dentifrice abrasivity does not seem to contribute to increased plaque removal with a manual toothbrush. It appears that the mechanical action provided by the use of a toothbrush is the main factor in the plaque-removing process.


Assuntos
Placa Dentária/terapia , Dentifrícios/uso terapêutico , Escovação Dentária , Adulto , Índice de Placa Dentária , Feminino , Humanos , Masculino , Dióxido de Silício/uso terapêutico , Método Simples-Cego , Fluoreto de Sódio/uso terapêutico
12.
JOP ; 7(1): 51-5, 2006 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-16407619

RESUMO

CONTEXT: Isolated pancreatic injuries resulting from non-penetrating trauma are rare. CT is currently the modality of choice in evaluating pancreatic injury. Delay in recognizing patients who need immediate surgery is an important cause of increased morbidity due to specific pancreatic complications. CASE REPORT: A 47-year-old man with blunt abdominal trauma after a car accident underwent a CT scan. Initial CT findings included diffuse pancreatic enlargement suggestive of isolated grade 1 pancreatic injury. A follow-up CT scan 3 days later revealed a fracture line at the pancreatic body. Subsequent surgical exploration confirmed the suspicion of concomitant duct transection. Seven months after surgery, a pseudocyst had formed adjacent to the site of the injury. CONCLUSIONS: This case demonstrates the potential importance of serial CT scans in the diagnosis, grading and management of isolated pancreatic injury.


Assuntos
Pâncreas/diagnóstico por imagem , Pâncreas/lesões , Ferimentos não Penetrantes/diagnóstico por imagem , Amilases/sangue , Hematócrito , Hemoglobinas/análise , Humanos , Escala de Gravidade do Ferimento , Masculino , Pessoa de Meia-Idade , Pâncreas/patologia , Pâncreas/cirurgia , Tomografia Computadorizada por Raios X , Ferimentos não Penetrantes/patologia , Ferimentos não Penetrantes/cirurgia
13.
Cell Death Differ ; 10(9): 987-96, 2003 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12934073

RESUMO

Phenotypic change of adult pancreatic islets has been implicated in the development of certain pancreatic cancers and in islet transplant failure. The aim of this study was to characterize intracellular events that mediate changes in adult islet phenotype. Using an in vitro islet-to-duct transformation model, canine islets were induced to undergo phenotypic transformation to duct-like epithelial structures through a two-stage process. Stage one was characterized by widespread islet cell apoptosis associated with the formation of cavitary spaces within the islets. During this stage, c-Jun N-terminal regulated kinase (JNK) and caspase-3 activities were elevated, while extracellular signal-regulated kinase (ERK) and Akt activities were decreased. The second stage of the process was characterized by an inversion in the balance in activity between these signal transduction pathways and by a concomitant decrease in apoptosis. The transformed islets were no longer immunoreactive for islet cell hormones, but expressed the duct epithelial cell marker CK-AE1/AE3. In contrast to islet cells, these duct epithelial cells were highly proliferative. To clarify the role of the identified changes in signal transduction events, we performed additional studies using pharmacological inhibitors of enzyme activity and demonstrated that inhibition of JNK and caspase-3 activity prevented cystic transformation. Our results indicate that the balance in signaling activity between ERK/Akt and JNK/caspase-3 appears to be an important regulator of islet cell death and differentiation.


Assuntos
Apoptose , Ilhotas Pancreáticas/citologia , Ductos Pancreáticos/citologia , Proteínas Serina-Treonina Quinases , Transdução de Sinais , Animais , Caspase 3 , Caspases/metabolismo , Diferenciação Celular , Divisão Celular , Células Cultivadas , Cães , Células Epiteliais/citologia , Células Epiteliais/enzimologia , Feminino , Ilhotas Pancreáticas/enzimologia , Cinética , Masculino , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Ductos Pancreáticos/enzimologia , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt
14.
J Pediatr Endocrinol Metab ; 18(4): 363-72, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15844470

RESUMO

Critical illness has an important impact on the human endocrine system. Very few studies have been performed to elucidate the alterations of the GH/IGF-I axis in acutely ill children. The aim of this study was to investigate several parameters of this axis in children with trauma (TRA) and sepsis (SEP) requiring admission to the pediatric intensive care unit (PICU). A total of 16 children, ten with TRA and six with SEP (age 1-10 years) as well as 18 healthy children (CS) of similar age and gender were included in the study. Two children, one with TRA and one with SEP, died. Serum IGF-I and -II, IGFBP-1 and -3, and GH levels were measured on days 1, 3 and 7 after admission. GH levels were higher in the patients than in CS (p = 0.04), with no difference between TRA and SEP, and were elevated during PICU stay (p = 0.05). Serum IGF-I, -II and IGFBP-3 were lower in the patients than in CS (p = 0.03, 0.02 and 0.001, respectively) with a tendency to increase up to day 7. Finally, IGFBP-1 levels were similar in the patients and CS. These findings indicate that critically ill children are characterized by low levels of IGF-I and -II as well as IGFBP-3 accompanied by elevated levels of GH, probably reflecting the development of peripheral GH resistance. No significant differences were found between the different catabolic conditions, sepsis and trauma.


Assuntos
Estado Terminal , Hormônio do Crescimento Humano/sangue , Fator de Crescimento Insulin-Like I/metabolismo , Sepse/sangue , Ferimentos e Lesões/sangue , Estudos de Casos e Controles , Criança , Pré-Escolar , Estado Terminal/mortalidade , Feminino , Humanos , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/sangue , Fator de Crescimento Insulin-Like II/metabolismo , Masculino , Estudos Prospectivos , Sepse/mortalidade , Ferimentos e Lesões/mortalidade
15.
Biomicrofluidics ; 9(4): 044125, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26339324

RESUMO

Human pancreatic islets are seldom assessed for dynamic responses to external stimuli. Thus, the elucidation of human islet functionality would provide insights into the progression of diabetes mellitus, evaluation of preparations for clinical transplantation, as well as for the development of novel therapeutics. The objective of this study was to develop a microfluidic platform for in vitro islet culture, allowing the multi-parametric investigation of islet response to chemical and biochemical stimuli. This was accomplished through the fabrication and implementation of a microfluidic platform that allowed the perifusion of islet culture while integrating real-time monitoring using impedance spectroscopy, through microfabricated, interdigitated electrodes located along the microchamber arrays. Real-time impedance measurements provide important dielectric parameters, such as cell membrane capacitance and cytoplasmic conductivity, representing proliferation, differentiation, viability, and functionality. The perifusion of varying glucose concentrations and monitoring of the resulting impedance of pancreatic islets were performed as proof-of-concept validation of the lab-on-chip platform. This novel technique to elucidate the underlying mechanisms that dictate islet functionality is presented, providing new information regarding islet function that could improve the evaluation of islet preparations for transplantation. In addition, it will lead to a better understanding of fundamental diabetes-related islet dysfunction and the development of therapeutics through evaluation of potential drug effects.

16.
FEBS Lett ; 455(3): 203-8, 1999 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-10437773

RESUMO

Isolation and purification of islet cells exposes them to ischemic, osmotic and mechanical stresses. The objective of this study was to determine the roles of the MAP-kinases in islets immediately following isolation. During the first 48 h, activity of JNK1 and JNK2 declined markedly. Activity of p38 increased steadily with time in culture while extracellular signal regulated kinase (ERK) activity declined dramatically within 24 h post-isolation. High p38 activation relative to ERK activation immediately following isolation correlated with a decrease in islet survival after 36 h in culture. Absence and/or transiency of ERK signaling in conjunction with sustained activation of p38 pathway could be an important regulator of cell death in islets during and following their isolation by commonly employed procedures.


Assuntos
Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Proteínas de Ciclo Celular , Sobrevivência Celular/fisiologia , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/enzimologia , Proteínas Quinases Ativadas por Mitógeno , Fosfoproteínas Fosfatases , Adolescente , Adulto , Animais , Apoptose/fisiologia , Separação Celular , Cães , Fosfatase 1 de Especificidade Dupla , Ativação Enzimática , Humanos , Proteínas Imediatamente Precoces/metabolismo , Técnicas In Vitro , Transplante das Ilhotas Pancreáticas , Proteínas Quinases JNK Ativadas por Mitógeno , Pessoa de Meia-Idade , Proteína Quinase 9 Ativada por Mitógeno , Proteínas Quinases/metabolismo , Proteína Fosfatase 1 , Proteínas Tirosina Fosfatases/metabolismo , Suínos , Proteínas Quinases p38 Ativadas por Mitógeno
17.
J Histochem Cytochem ; 47(4): 499-506, 1999 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10082751

RESUMO

The reasons for the failure of clinical islet transplantation remain obscure. Islet isolation, however, exposes the islet to variety of cellular stresses, including disruption of the cell-matrix relationship, an event associated with apoptosis. The cell-matrix relationship is characterized by an interaction between cell surface integrin receptors and matrix molecules of the surrounding basement membrane (BM). The purpose of this study was to characterize integrin expression and the distribution of the peri-insular BM in human, porcine, canine, and hamster pancreas, and after routine islet isolation. Whereas islets in the porcine pancreas do not have a demonstrable BM, islets in the human, canine, and hamster pancreas have an almost continuous BM with very little direct exocrine to endocrine cell-cell contact. After islet isolation, the BM was destroyed, only to be reestablished during the period of culture. In the pancreas of all four species, integrin alpha3 was expressed only on islet cells, and integrin alpha5 was present on islet cells as well as on acinar, centroacinar, and duct cells. Integrin alphaV was detected only in human and canine pancreas. Integrin beta1 was demonstrated only in the human pancreas. In isolated islets, integrin alpha3, alpha5, and alphaV expression decreased during the culture period and the intensity of the staining was observed to be coincident with the distribution of the BM. In summary, this is the first report of integrin expression in hamster, canine, porcine, and human islets. After islet isolation, the altered islet cell-matrix relationship is reflected both in the decrease in integrin expression and in the destruction of the peri-insular BM. These profound changes will need to be considered as the process of islet isolation for transplantation is refined. (J Histochem Cytochem 47:499-506, 1999)


Assuntos
Integrinas/biossíntese , Ilhotas Pancreáticas/metabolismo , Adulto , Animais , Membrana Basal/metabolismo , Células Cultivadas , Colágeno/metabolismo , Cricetinae , Cães , Feminino , Humanos , Imuno-Histoquímica , Laminina/metabolismo , Masculino , Pessoa de Meia-Idade , Fatores de Tempo
18.
Surgery ; 126(2): 393-8, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10455912

RESUMO

BACKGROUND: Islet isolation exposes the islet to a variety of cellular stresses and disrupts the cell-matrix relationship--events known to be associated with apoptosis. The purpose of this study was to determine whether islet isolation leads invariably to islet cell death and to specify the mechanisms involved. METHODS: Canine islets were isolated using Liberase CI and purified using a centrifuge. Islets were sampled for up to 5 days in culture and analyzed by routine histology, electron microscopy, immunocytochemistry, and reticulin staining for basement membrane. Apoptosis was assessed by cell death enzyme-linked immunosorbent assay and terminal deoxynucleotidyl transferase-mediated decoxyuridine triphosphate nick and labeling (TUNEL) assay. Activation of the prosurvival ERK1/2 and proapoptotic p38 and JNK were determined by immunoblotting. RESULTS: Immediately after isolation, the peri-insular basement membrane was absent, and integrin-alpha 5 expression diminished. DNA fragmentation rose from 2.5 +/- 1.8 (arbitrary units) on the day of isolation to 42.4 +/- 6.7 48 hours later (P < .05), coinciding with the appearance of pyknotic nuclei and apoptotic bodies. The apoptotic index determined by TUNEL assay increased from 5% +/- 1% on the day of isolation to 60% +/- 2% on day 5 (P < .01), and most of the affected cells were beta-cells. Finally, the p38 and JNK activity were elevated relative to ERK1/2. CONCLUSIONS: During isolation, islet cells undergo profound changes in structure and function, resulting in beta-cell apoptosis. These findings suggest that strategies directed to the manipulation of the cell-matrix relationship and the modulation of mitogen-activated protein kinase signal transduction may offer a valuable new approach to improving islet transplant outcome.


Assuntos
Apoptose , Transplante das Ilhotas Pancreáticas , Ilhotas Pancreáticas/patologia , Proteínas Quinases JNK Ativadas por Mitógeno , Quinases de Proteína Quinase Ativadas por Mitógeno , Animais , Separação Celular , Cães , Feminino , Marcação In Situ das Extremidades Cortadas , Ilhotas Pancreáticas/fisiologia , MAP Quinase Quinase 4 , Masculino , Fosforilação , Proteínas Quinases/metabolismo
19.
Pancreas ; 20(3): 270-6, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10766453

RESUMO

Purified islet allografts have largely failed to maintain long-term glucose homeostasis in human recipients, and the reasons for this are unclear. It is noteworthy, however, that islet isolation destroys or removes cellular and noncellular elements of the pancreas that could play an important role in supporting islet survival. The purpose of this study was to determine whether human islet isolation leads to the induction of programmed cell death. Human islets were enzymatically isolated from cadaveric donor pancreata using Liberase or Collagenase P, purified over a discontinuous BSA gradient, then cultured in RPMI 1640 at 37 degrees C in 5% CO2 for < or = 7 days. Islets were examined daily by routine histology and immunocytochemistry for islet hormones, DNA fragmentation [cell death; enzyme-linked immunosorbent assay (ELISA) and TUNEL assay] and for transglutaminase (TG) activity, two indicators of apoptosis. TG activity and DNA fragmentation increased by 1,000% and 1,890%, respectively (p < 0.05) This corresponded to the appearance of pyknotic nuclei on light microscopy, the presence of apoptotic bodies on electron microscopy, and the demonstration of TUNEL-positive cells. These were present primarily in a distribution that corresponded to the insulin-immunoreactive cells. At 5 days, 31.4 +/- 2.2% of islet cells were TUNEL positive. In summary, apoptosis of islet cells appears soon after islet isolation, and involves primarily the beta cell. This is the first report of apoptosis of islet cells after human islet isolation. The loss of beta-cell mass could be implicated in the failure of islet transplantation and merits further investigation.


Assuntos
Apoptose , Ilhotas Pancreáticas/citologia , Adolescente , Adulto , Cadáver , Separação Celular , Colagenases , Fragmentação do DNA , Ensaio de Imunoadsorção Enzimática , Humanos , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Microscopia Eletrônica , Pessoa de Meia-Idade , Termolisina , Transglutaminases/metabolismo
20.
Pancreas ; 13(1): 89-95, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8783339

RESUMO

Chronic pancreatitis (CP) is characterized by the presence of an inflammatory infiltrate with progressive destruction of acinar cells and fibrosis. The finding that endothelin-1 (ET-1), an endothelium-derived peptide having vasoconstrictive and mitogenic properties, reduces pancreatic blood flow (PBF) in normal rats suggested that the peptide may be associated with the reduced PBF seen in animal models of CP and with the morphological abnormalities of the disease. This study investigates changes in blood flow to the pancreas and other abdominal organs in a rat model of CP and compares ET-1 production in the pancreata of these rats and normal controls. CP was induced in male Wistar rats by the injection of oleic acid into the common bile/pancreatic duct. The radiolabeled microsphere technique was employed to measure blood flow to the pancreas, duodenum, liver, spleen, and kidneys. Immunohistochemistry was used to investigate the cellular production of ET-1. After 3 weeks, significant decreases were noted in body weight, pancreatic weight, and pancreatic DNA, amylase, and protein content in the animals with CP. PBF was reduced by 64% and duodenal blood flow by 80% relative to those in control animals. Hepatic and splenic blood flows were increased by 91 and 88%, respectively, compared to those in controls. A 50% decrease in renal blood flows were increased by 91 and 88%, respectively, compared to those in controls. A 50% decrease in renal blood flow was also seen in the experimental group after 3 weeks. Pancreata from animals with CP stained diffusely for ET-1 in the cytoplasm of vascular endothelial, acinar, and ductal cells. In the control pancreata, focal staining for ET-1 was observed only in acinar cells. This difference was significant in endothelial and ductal cells. There was weak staining of islet cells in both groups. The results suggest that elevation in local production of ET-1 may be associated with the morphological and hemodynamic changes of CP.


Assuntos
Endotelina-1/biossíntese , Pâncreas/irrigação sanguínea , Pâncreas/metabolismo , Pancreatite/fisiopatologia , Animais , Velocidade do Fluxo Sanguíneo , Doença Crônica , Modelos Animais de Doenças , Imuno-Histoquímica , Masculino , Microcirculação/fisiopatologia , Microesferas , Pancreatite/metabolismo , Ratos , Ratos Wistar , Fluxo Sanguíneo Regional
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