RESUMO
INTRODUCTION: Iliac lymphadenectomy is performed to provide anastomotic access during the vascular implantation procedure in renal transplantation. Iliac lymph nodes (LNs) are often enlarged, but there are no standardised guidelines for the management of incidentally enlarged LNs during transplantation. We aimed to evaluate histological findings of LNs sent for examination at our unit. METHODS: Patients were evaluated in two distinct date cycles. In the first cycle, lymphadenectomy and histological assessment were performed at the discretion of the transplanting surgeon. In the second cycle, all incidentally enlarged LNs were sent for histological assessment, regardless of size. RESULTS: In the first cycle (n = 76), 11 patients (14.47%) had incidentally enlarged iliac LNs on lymphadenectomy and histology showed only reactive changes. In the second cycle (n = 165), eight patients (4.85%) had incidentally enlarged LNs on lymphadenectomy. One patient was found to have mature B cell chronic lymphocytic leukaemia. The patient was referred to haematology and a "watch and wait" approach was taken, with the patient still alive at last follow-up (511 days post-transplantation). DISCUSSION: There are currently no published guidelines on the management of incidentally enlarged iliac LNs during transplantation. Current literature suggests that clinically significant lymphadenopathy needs to be investigated in all patients. Based on our centre's experience of a 5.26% (1 in 19) positive pathological LN sampling, we recommend that all incidental LNs with suspicious features and/or that are greater than 10mm in diameter should be considered for histological, microbiological and molecular assessment as appropriate.
Assuntos
Transplante de Rim , Linfadenopatia , Humanos , Transplante de Rim/efeitos adversos , Linfadenopatia/etiologia , Linfonodos/cirurgia , Excisão de Linfonodo , Anastomose CirúrgicaRESUMO
INTRODUCTION: Enhanced recovery after surgery (ERAS) is well established in many specialties but has not been widely adopted in renal transplantation. The aim of this survey was to understand current national practices and sentiment concerning ERAS for renal transplant recipients in the UK. METHODOLOGY: A national web-based survey was sent to consultant surgeons at all 23 UK adult renal transplant units. Completed questionnaires were collected between May and July 2020. Data were analysed according to individual responses and grouped according to the existence of formal ERAS pathways within units. RESULTS: All transplant units were represented in this survey. Three units had a formal ERAS pathway for all recipients. Of the remaining units, 65.9% considered implementing an ERAS pathway in the near future. The most commonly perceived barrier to ERAS implementation was 'embedded culture within transplant units' (54.8% of respondents). A fifth of respondents insert surgical drains selectively and 11.7% routinely discontinue patient-controlled analgesia on postoperative day 1. Most respondents routinely remove urinary catheters on day 5 (70%) and ureteric stents 4-6 weeks post-transplantation (81.7%). Median length of stay for deceased donor kidney transplant recipients was lower in units with ERAS programmes (5-7 days versus 8-10 days, respectively). The main cited barriers for discharge were 'suboptimal fluid balance' and 'requirement of treatment for rejection'. CONCLUSIONS: Despite slow uptake of ERAS in kidney transplantation, appetite appears to be increasing, particularly in the post-COVID-19 era. The current practice and opinions of transplant specialists highlighted in this survey may help to establish nationally agreed ERAS guidelines in this field.
Assuntos
COVID-19 , Recuperação Pós-Cirúrgica Melhorada , Transplante de Rim , Cirurgiões , Adulto , Humanos , COVID-19/epidemiologia , COVID-19/prevenção & controle , Reino Unido , Tempo de Internação , Complicações Pós-OperatóriasRESUMO
Indications for liver transplantation have expanded over the past few decades owing to improved outcomes and better understanding of underlying pathologies. In particular, there has been a growing interest in the field of transplant oncology in recent years that has led to considerable developments which have pushed the boundaries of malignant indications for liver transplantation beyond hepatocellular carcinoma (HCC). In this article, we review and summarise the published evidence for liver transplantation in non-HCC primary and metastatic liver malignancies and highlight ongoing clinical trials that address unresolved questions therein. We also examine the current technical, immunological and oncological challenges that face liver transplantation in this growing field and explore potential approaches to overcome these barriers.
Assuntos
Neoplasias Hepáticas/cirurgia , Transplante de Fígado , Carcinoma Hepatocelular/cirurgia , Colangiocarcinoma/cirurgia , Neoplasias Colorretais/patologia , Hemangioendotelioma Epitelioide/cirurgia , Hepatoblastoma/cirurgia , Humanos , Neoplasias Hepáticas/secundário , Tumores Neuroendócrinos/patologiaRESUMO
BACKGROUND: A significant proportion of donation after circulatory death (DCD) kidneys are declined for transplantation because of concerns over their quality. Ex vivo normothermic machine perfusion (NMP) provides a unique opportunity to assess the quality of a kidney and determine its suitability for transplantation. METHODS: In phase 1 of this study, declined human DCD kidneys underwent NMP assessment for 60 min. Kidneys were graded 1-5 using a quality assessment score (QAS) based on macroscopic perfusion, renal blood flow and urine output during NMP. In phase 2 of the study, declined DCD kidneys were assessed by NMP with an intention to transplant them. RESULTS: In phase 1, 18 of 42 DCD kidneys were declined owing to poor in situ perfusion. After NMP, 28 kidneys had a QAS of 1-3, and were considered suitable for transplantation. In phase 2, ten of 55 declined DCD kidneys underwent assessment by NMP. Eight kidneys had been declined because of poor in situ flushing in the donor and five of these were transplanted successfully. Four of the five kidneys had initial graft function. CONCLUSION: NMP technology can be used to increase the number of DCD kidney transplants by assessing their quality before transplantation.
Assuntos
Seleção do Doador , Transplante de Rim , Rim/irrigação sanguínea , Preservação de Órgãos/métodos , Perfusão/métodos , Adulto , Idoso , Morte , Feminino , Humanos , Rim/fisiologia , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , TemperaturaRESUMO
Aberrant cell death/survival has a critical role in the development of hepatocellular carcinoma (HCC). Caspase-2, a cell death protease, limits oxidative stress and chromosomal instability. To study its role in reactive oxygen species (ROS) and DNA damage-induced liver cancer, we assessed diethylnitrosamine (DEN)-mediated tumour development in caspase-2-deficient (Casp2(-/-)) mice. Following DEN injection in young animals, tumour development was monitored for 10 months. We found that DEN-treated Casp2(-/-) mice have dramatically elevated tumour burden and accelerated tumour progression with increased incidence of HCC, accompanied by higher oxidative damage and inflammation. Furthermore, following acute DEN injection, liver injury, DNA damage, inflammatory cytokine release and hepatocyte proliferation were enhanced in mice lacking caspase-2. Our study demonstrates for the first time that caspase-2 limits the progression of tumourigenesis induced by an ROS producing and DNA damaging reagent. Our findings suggest that after initial DEN-induced DNA damage, caspase-2 may remove aberrant cells to limit liver damage and disease progression. We propose that Casp2(-/-) mice, which are more susceptible to genomic instability, are limited in their ability to respond to DNA damage and thus carry more damaged cells resulting in accelerated tumourigenesis.
Assuntos
Caspase 2/deficiência , Neoplasias Hepáticas/induzido quimicamente , Neoplasias Hepáticas/patologia , Animais , Carcinoma Hepatocelular/induzido quimicamente , Carcinoma Hepatocelular/enzimologia , Carcinoma Hepatocelular/patologia , Caspase 2/metabolismo , Morte Celular , Proliferação de Células , Dano ao DNA , Dietilnitrosamina , Ativação Enzimática , Inflamação/complicações , Inflamação/patologia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Fígado/patologia , Neoplasias Hepáticas/enzimologia , Masculino , Camundongos Endogâmicos C57BL , Estadiamento de Neoplasias , Estresse Oxidativo , Estresse FisiológicoRESUMO
Caspase-2 belongs to the caspase family of cysteine proteases with established roles in apoptosis. Recently, caspase-2 has been implicated in nonapoptotic functions including maintenance of genomic stability and tumor suppression. Our previous studies demonstrated that caspase-2 also regulates cellular redox status and delays the onset of several ageing-related traits. In the current study, we tested stress tolerance ability in caspase-2-deficient (Casp2(-/-)) mice by challenging both young and old mice with a low dose of the potent reactive oxygen species (ROS) generator, PQ that primarily affects lungs. In both groups of mice, PQ induced pulmonary damage. However, the lesions in caspase-2 knockout mice were consistently and reproducibly more severe than those in wild-type (WT) mice. Furthermore, serum interleukin (IL)-1ß and IL-6 levels were higher in PQ-exposed aged Casp2(-/-) mice indicating increased inflammation. Interestingly, livers from Casp2(-/-) mice displayed karyomegaly, a feature commonly associated with ageing and aneuploidy. Given that Casp2(-/-) mice show impaired antioxidant defense, we tested oxidative damage in these mice. Protein oxidation significantly increased in PQ-injected old Casp2(-/-) mice. Moreover, FoxO1, SOD2 and Nrf2 expression levels were reduced and induction of superoxide dismutase (SOD) and glutathione peroxidase activity was not observed in PQ-treated Casp2(-/-) mice. Strong c-Jun amino-terminal kinase (JNK) activation was observed in Casp2(-/-) mice, indicative of increased stress. Together, our data strongly suggest that caspase-2 deficiency leads to increased cellular stress largely because these mice fail to respond to oxidative stress by upregulating their antioxidant defense mechanism. This makes the mice more vulnerable to exogenous challenges and may partly explain the shorter lifespan of Casp2(-/-) mice.
Assuntos
Caspase 2/metabolismo , Estresse Oxidativo , Animais , Caspase 2/genética , Herbicidas/toxicidade , Interleucina-1beta/biossíntese , Interleucina-6/biossíntese , Camundongos , Camundongos Knockout , Estresse Oxidativo/efeitos dos fármacos , Paraquat/toxicidadeRESUMO
Caspase-2 has been implicated in various cellular functions, including cell death by apoptosis, oxidative stress response, maintenance of genomic stability and tumor suppression. The loss of the caspase-2 gene (Casp2) enhances oncogene-mediated tumorigenesis induced by E1A/Ras in athymic nude mice, and also in the Eµ-Myc lymphoma and MMTV/c-neu mammary tumor mouse models. To further investigate the function of caspase-2 in oncogene-mediated tumorigenesis, we extended our studies in the TH-MYCN transgenic mouse model of neuroblastoma. Surprisingly, we found that loss of caspase-2 delayed tumorigenesis in the TH-MYCN neuroblastoma model. In addition, tumors from TH-MYCN/Casp2(-/-) mice were predominantly thoracic paraspinal tumors and were less vascularized compared with tumors from their TH-MYCN/Casp2(+/+) counterparts. We did not detect any differences in the expression of neuroblastoma-associated genes in TH-MYCN/Casp2(-/-) tumors, or in the activation of Ras/MAPK signaling pathway that is involved in neuroblastoma progression. Analysis of expression array data from human neuroblastoma samples showed a correlation between low caspase-2 levels and increased survival. However, caspase-2 levels correlated with clinical outcome only in the subset of MYCN-non-amplified human neuroblastoma. These observations indicate that caspase-2 is not a suppressor in MYCN-induced neuroblastoma and suggest a tissue and context-specific role for caspase-2 in tumorigenesis.
Assuntos
Caspase 2/metabolismo , Neuroblastoma/patologia , Animais , Caspase 2/deficiência , Caspase 2/genética , Modelos Animais de Doenças , Humanos , Estimativa de Kaplan-Meier , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Neuroblastoma/metabolismo , Neuroblastoma/mortalidade , Transdução de Sinais , Proteínas ras/metabolismoRESUMO
Reversibly switchable proteins are powerful tools with which to explore protein function in vitro and in vivo. For example, the activity of many proteins fused to the hormone-binding domain of the modified oestrogen receptor (ER(TAM)) can be regulated by provision or removal of 4-hydroxytamoxifen (4-OHT). Despite the widespread use of ER(TAM) fusions in vivo, inadequate data are available as to the most efficacious routes for systemic tamoxifen delivery. In this study, we have used two well-characterized ER(TAM) fusion proteins, both reversibly activated by 4-OHT, to compare the effectiveness and kinetics of 4-OHT delivery in mice in vivo by either tamoxifen in food or by intraperitoneal injection. Our data indicate that dietary tamoxifen offers an effective, facile and ethically preferable means for long-term activation of ER(TAM) fusion proteins in vivo.
Assuntos
Antineoplásicos/administração & dosagem , Receptores de Estrogênio/genética , Tamoxifeno/análogos & derivados , Administração Oral , Animais , Antineoplásicos/farmacologia , Genes Reporter , Injeções Intraperitoneais , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Cinética , Camundongos , Ratos , Receptores de Estrogênio/biossíntese , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/genética , Tamoxifeno/administração & dosagem , Tamoxifeno/farmacologia , Ativação Transcricional/efeitos dos fármacos , Proteína Supressora de Tumor p53/biossíntese , Proteína Supressora de Tumor p53/genéticaRESUMO
INTRODUCTION: Extraskeletal Ewing's sarcoma is reported in the medical literature, but none has been described as presenting with a resectable liver mass. METHODS: A case of a 29-year-old male patient who presented with a large symptomatic mass in the right lobe of the liver which, following resection, demonstrated the characteristic histopathology and fusion protein (EWSR1-Fli1) found in Ewing's sarcoma was reported. DISCUSSION: Complete surgical resection offers the best long-term outlook. Cure rates with appropriate surgical and chemotherapeutic management range between 30 and 60 %.
Assuntos
Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/cirurgia , Sarcoma de Ewing/patologia , Sarcoma de Ewing/cirurgia , Adulto , Humanos , Neoplasias Hepáticas/diagnóstico por imagem , Masculino , Radiografia , Sarcoma de Ewing/diagnóstico por imagemRESUMO
Caspase-2 is an initiator caspase, which has been implicated to function in apoptotic and non-apoptotic signalling pathways, including cell-cycle regulation, DNA-damage signalling and tumour suppression. We previously demonstrated that caspase-2 deficiency enhances E1A/Ras oncogene-induced cell transformation and augments lymphomagenesis in the EµMyc mouse model. Caspase-2(-/-) mouse embryonic fibroblasts (casp2(-/-) MEFs) show aberrant cell-cycle checkpoint regulation and a defective apoptotic response following DNA damage. Disruption of cell-cycle checkpoints often leads to genomic instability (GIN), which is a common phenotype of cancer cells and can contribute to cellular transformation. Here we show that caspase-2 deficiency results in increased DNA damage and GIN in proliferating cells. Casp2(-/-) MEFs readily escape senescence in culture and exhibit increased micronuclei formation and sustained DNA damage during cell culture and following γ-irradiation. Metaphase analyses demonstrated that a lack of caspase-2 is associated with increased aneuploidy in both MEFs and in EµMyc lymphoma cells. In addition, casp2(-/-) MEFs and lymphoma cells exhibit significantly decreased telomere length. We also noted that loss of caspase-2 leads to defective p53-mediated signalling and decreased trans-activation of p53 target genes upon DNA damage. Our findings suggest that loss of caspase-2 serves as a key function in maintaining genomic integrity, during cell proliferation and following DNA damage.
Assuntos
Caspase 2/deficiência , Dano ao DNA , Instabilidade Genômica , Aneuploidia , Animais , Caspase 2/genética , Caspase 2/metabolismo , Processos de Crescimento Celular/genética , Células Cultivadas , Modelos Animais de Doenças , Embrião de Mamíferos/citologia , Fibroblastos/citologia , Fibroblastos/fisiologia , Humanos , Camundongos , Camundongos Knockout , Transdução de Sinais , TransfecçãoAssuntos
Adesivo Tecidual de Fibrina/uso terapêutico , Hemostáticos/uso terapêutico , Laparoscopia , Pancreatectomia/efeitos adversos , Fístula Pancreática/prevenção & controle , Neoplasias Pancreáticas/cirurgia , Adesivos Teciduais/uso terapêutico , Humanos , Pancreatectomia/métodos , Fístula Pancreática/etiologia , Resultado do TratamentoRESUMO
Somatically acquired, activating mutations of GNAS, the gene encoding the stimulatory G-protein Gsalpha subunit, have been identified in kidney, thyroid, pituitary, leydig cell, adrenocortical and, more recently, in colorectal tumours, suggesting that mutations such as R201C may be oncogenic in these tissues. To study the role of GNAS in intestinal tumourigenesis, we placed GNAS R201C under the control of the A33-antigen promoter (Gpa33), which is almost exclusively expressed in the intestines. The GNAS R201C mutation has been shown to result in the constitutive activation of Gsalpha and adenylate cyclase and to lead to the autonomous synthesis of cyclic adenosine monophosphate (cAMP). Gpa33(tm1(GnasR201C)Wtsi/+) mice showed significantly elevated cAMP levels and a compensatory upregulation of cAMP-specific phosphodiesterases in the intestinal epithelium. GNAS R201C alone was not sufficient to induce tumourigenesis by 12 months, but there was a significant increase in adenoma formation when Gpa33(tm1(GnasR201C)Wtsi/+) mice were bred onto an Apc(Min/+) background. GNAS R201C expression was associated with elevated expression of Wnt and extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase (ERK1/2 MAPK) pathway target genes, increased phosphorylation of ERK1/2 MAPK and increased immunostaining for the proliferation marker Ki67. Furthermore, the effects of GNAS R201C on the Wnt pathway were additive to the inactivation of Apc. Our data strongly suggest that activating mutations of GNAS cooperate with inactivation of APC and are likely to contribute to colorectal tumourigenesis.
Assuntos
Proteína da Polipose Adenomatosa do Colo/metabolismo , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Subunidades alfa Gs de Proteínas de Ligação ao GTP/metabolismo , Sistema de Sinalização das MAP Quinases , Proteínas Mutantes/metabolismo , Proteínas Wnt/metabolismo , Adenoma/enzimologia , Adenoma/genética , Adenoma/metabolismo , Adenoma/patologia , Alelos , Animais , Diferenciação Celular/genética , Proliferação de Células , Cromograninas , Neoplasias Colorretais/enzimologia , Neoplasias Colorretais/metabolismo , AMP Cíclico/metabolismo , Progressão da Doença , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Feminino , Subunidades alfa Gs de Proteínas de Ligação ao GTP/genética , Regulação Neoplásica da Expressão Gênica , Loci Gênicos/genética , Humanos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Masculino , Glicoproteínas de Membrana/genética , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Proteínas Mutantes/genética , Mutação , Especificidade de Órgãos , Diester Fosfórico Hidrolases/metabolismo , Regiões Promotoras Genéticas/genética , Células-Tronco/metabolismo , Células-Tronco/patologia , Especificidade por Substrato , Regulação para CimaRESUMO
BACKGROUND: Kidneys from non-heart-beating donors (NHBDs) have high rates of delayed graft function (DGF). Use of calcineurin inhibitors is associated with a reduction in renal blood flow, which may delay graft recovery from ischaemic acute tubular necrosis. METHODS: To assess whether daclizumab (DZB) could safely replace tacrolimus in the immediate postoperative period, patients were randomized to receive DZB induction and daily mycophenolate mofetil with steroids (DZB group) or standard tacrolimus-based triple therapy (control group). Tacrolimus was given to patients in the DZB group when the serum creatinine level dropped below 350 micromol/l. RESULTS: Fifty-one patients were recruited at two centres over a 2-year interval between 2000 and 2003. The overall rate of immediate function was 28 per cent (13 of 46 grafts), with the highest rate in recipients of machine-perfused kidneys treated with DZB (eight of 15 patients). CONCLUSION: Induction with DZB and delayed introduction of tacrolimus reduced the incidence of DGF in recipients of machine-perfused NHBD kidneys.
Assuntos
Anticorpos Monoclonais/uso terapêutico , Imunoglobulina G/uso terapêutico , Imunossupressores/uso terapêutico , Transplante de Rim/métodos , Ácido Micofenólico/análogos & derivados , Tacrolimo/uso terapêutico , Adulto , Idoso , Anticorpos Monoclonais Humanizados , Daclizumabe , Quimioterapia Combinada , Feminino , Sobrevivência de Enxerto , Humanos , Masculino , Pessoa de Meia-Idade , Ácido Micofenólico/uso terapêutico , Estatísticas não Paramétricas , Doadores de Tecidos , Resultado do TratamentoRESUMO
A method is described for characterizing disaggregatory and proaggregatory prostanoids in a single assay. This "post-addition assay" consists of adding the test agent to PRP containing PGI2 (4-6 nM) 90 sec after an ADP challenge. The relative potencies of known inhibitors of ADP-induced aggregation were identical to the relative disaggregatory potencies determined by post-addition. The proaggregatory relative potencies for 16, 16-Me2-PGE2,PGE2,PGH2 and 11 alpha,9 alpha-epoxymethano-15 alpha-hydroxy-prostadienoic acid were 5.8 :2 : 1.8 : 1, respectively, revealing the significant thrombosis promoting activity of PGE2 and its analogs.
Assuntos
Plaquetas/efeitos dos fármacos , Ácidos Graxos/farmacologia , Agregação Plaquetária , Ácidos Prostanoicos/farmacologia , Difosfato de Adenosina/farmacologia , Relação Dose-Resposta a Droga , Epoprostenol/farmacologia , Humanos , Métodos , Prostaglandinas E/farmacologiaRESUMO
During the 36-month period from July, 1978, through July, 1981, 25 patients underwent a subxiphoid pericardial window procedure for diagnosis and therapy. Twelve patients were operated on for uremic pericarditis, 6 for malignancy, and 7 for etiological diagnosis of the pericarditis. All 12 patients with renal failure had enlarging effusions, despite aggressive dialysis. Eleven of the 12 are alive, free from recurrence, 3 to 36 months postoperatively. Six patients were operated on for suspected pericardial malignancy with hemodynamic compromise. Histological diagnosis was made from the pericardial tissue in all patients; only 1 patient lived more than 43 days following the procedure. In the group of 7 patients operated on for diagnosis, 4 were thought preoperatively to have tuberculous pericarditis. All 4 were treated with anti-tuberculosis chemotherapy and are asymptomatic, without evidence of calcification, 12 to 31 months postoperatively. This diverse group of patients demonstrates that the subxiphoid pericardial window is an effective approach for relief of uremic effusions and may adequately treat effusive tuberculous pericarditis when combined with multidrug chemotherapy. Patients with suspected malignant pericardial disease and hemodynamic compromise need to be carefully studied before an operative procedure is considered as a means of diagnosis and therapy.
Assuntos
Derrame Pericárdico/cirurgia , Pericardite/cirurgia , Adulto , Idoso , Antituberculosos/uso terapêutico , Neoplasias Cardíacas/cirurgia , Humanos , Métodos , Pessoa de Meia-Idade , Pericardite/etiologia , Pericardite Tuberculosa/tratamento farmacológico , Pericardite Tuberculosa/cirurgia , Pericárdio , Uremia/complicaçõesRESUMO
A young female with cerebral and left arm symptoms from the congenital subclavian steal syndrome is presented. Surgical correction was performed using an axillary-axillary bypass. Pre-operative noninvasive vascular evaluation demonstrated reversal of flow in the left carotid artery which was corrected postoperatively. There was complete relief of symptoms and equal upper extremity blood pressure. This report represents the first instance in which this extremely rare congenital disorder was fully evaluated with noninvasive vascular techniques, and the first to be treated with an extra-anatomical surgical approach.
Assuntos
Síndrome do Roubo Subclávio/congênito , Adulto , Angiografia , Artéria Axilar/cirurgia , Feminino , Humanos , Síndrome do Roubo Subclávio/diagnóstico por imagem , Síndrome do Roubo Subclávio/cirurgiaRESUMO
Methods for the evaluation of competitive interactions at receptors associated with platelet activation and inhibition using aggregometry of human PRP have been developed. The evidence supports the suggestion that PGE1 and PGI2 share a common receptor for inhibition of platelet reactivity, but only a portion (if any) of the aggregation stimulation associated with PGE2 is the result of PGE2 binding (without efficacy) to this receptor. PGE2 (at .3-20 microM) is an effective antagonist of PGE1, PGI2, and PGD2 producing a shift of about one order of magnitude in the IC50-values obtained from complete aggregation inhibition dose response curves. The antagonism of PGD2 inhibition is particularly notable, 80 nM PGE2 levels are detectable. This and other actions of PGE2 indicate another platelet receptor for PGE2. PGE1 acts at both the PGE2 and PGI2 receptor. Other substances showing PGI2-like actions only at high doses (1-30 microM), display additive responses with PGI2 indicative of decreased affinity for the I2/E1 receptor and the absence of PGE2-like aggregation stimulation activity. PGI2 methyl ester has intrinsic inhibitory action not associated with in situ ester hydrolysis. The methyl ester is dissaggregatory showing particular specificity for inhibition of release and second wave aggregation.
Assuntos
Plaquetas/metabolismo , Agregação Plaquetária , Receptores de Superfície Celular/metabolismo , Receptores de Prostaglandina/metabolismo , Difosfato de Adenosina/farmacologia , Ligação Competitiva , Epoprostenol/farmacologia , Humanos , Técnicas In Vitro , Agregação Plaquetária/efeitos dos fármacos , Prostaglandinas D/farmacologia , Prostaglandinas E Sintéticas/farmacologia , Prostaglandinas Sintéticas/farmacologiaAssuntos
Plaquetas/metabolismo , Epoprostenol/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Prostaglandinas D/farmacologia , Prostaglandinas E/farmacologia , Prostaglandinas/farmacologia , Receptores de Superfície Celular/metabolismo , Receptores de Prostaglandina/metabolismo , Difosfato de Adenosina/farmacologia , Plaquetas/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Relação Estrutura-AtividadeRESUMO
Thirty people with classical or definite rheumatoid arthritis received laser exposure to a Q-switch neodymium laser that operated at 1.06 micrometer with an output of 15 joules/cm2 for 30 nsec. One hand was lased at the proximal interphalangeal (PIP) and metacarpal phalangeal (MCP) joints, whereas the other hand was sham lased. The patient, physician, and occupational therapy evaluators did not know which hand was being lased. Twenty-one patients noted improvement of both their MCP and PIP joints of both hands during laser therapy. Twenty-seven noted improvement of their PIP joints and 26 noted improvement of the MCP joints during therapy. Heat, erythema, pain, swelling, and tenderness all improved with time in both hands, but the lased hand had more significant improvement in erythema and pain. There was also significant improvement in grasp and tip pressure on the lased side. The level of circulating immune complexes as measured by platelet aggregation decreased during lasing. The improvement may be related to laser exposure. The exact role that laser radiation has upon rheumatoid arthritis and its mechanism of action remain to be elucidated.