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1.
Artigo em Inglês | MEDLINE | ID: mdl-38803276

RESUMO

BACKGROUND: The superiority of anatomical liver resection (AR) for localized hepatocellular carcinoma (HCC) over nonanatomical liver resection (NR) remains controversial. This study aimed to investigate the impact of AR in preventing local and early HCC recurrence. METHODS: A total of 280 patients who underwent initial liver resection for solitary HCC ≤5 cm in diameter were categorized into the AR and NR groups and compared using propensity score matching analysis. RESULTS: Between the matched pairs (n = 87 in each group), the incidence rates of local and early (recurrence within 2 years after surgery) recurrences in the AR group were significantly lower than those in the NR group (13.8% vs. 28.7%, p = .025; 20.7% vs. 35.6%, p = .028, respectively). The overall survival in the AR group was better than that in the NR group (median: 13.4 vs. 7.6 years, p = .003). NR was among independent risk factors for early recurrence (odds ratio: 1.98, 95% CI: 1.1-3.6, p = .023) and prognostic factors for local recurrence (hazard ratio: 2.44, 95% CI: 1.4-4.4, p = .003). CONCLUSION: AR is superior in controlling local and early recurrence postoperatively for solitary HCC ≤5 cm in diameter compared with NR.

2.
Asian J Surg ; 2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38688761

RESUMO

BACKGROUND: Portal vein embolization (PVE) followed by major hepatectomy is a common treatment strategy for patients with perihilar cholangiocarcinoma (PHCC); however, the long-term dynamics of the liver remnant volume (LRV) remain unclear. Here, we report the dynamics of the LRV in patients who underwent hepatectomy following PVE. METHODS: A total of 39 patients with PHCC who underwent right hemihepatectomy or left trisectionectomy with extrahepatic bile duct resection between 2004 and 2021 were enrolled in this study [PVE (n = 27) and non-PVE (n = 12]). Long-term remnant liver dynamics were analyzed in propensity score-matched pairs (n = 10/group). RESULTS: The LRV/future liver remnant volume (FLRV) at 1 week to 1 month after hepatectomy were smaller in the PVE group than in the non-PVE group (1.53 vs. 1.69, p = .044 and 1.52 vs 1.99, p = .003, respectively). In the non-PVE group, the LRV/FLRV ratio plateaued 1-3 months postoperatively, whereas progressive hypertrophy occurred in the PVE group, and the LRV/FLRV ratio became equal in both groups at 1 year after hepatectomy (1.96 vs. 1.97; p = .799). Multivariate analysis revealed that FLRV/total liver volume (TLV) ≤ 0.43 was the only independent predictor of LRV/FLRV ≥1.9 at 1 year after hepatectomy (odds ratio:5.345, 95% confidence interval:1.210-23.615; p = .027). CONCLUSION: Although the long-term LRV was nearly equal in both groups, short-term LRV hypertrophy was lower in the PVE group than in the non-PVE group.

3.
Am J Surg Pathol ; 48(6): 751-760, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38584480

RESUMO

Intrahepatic cholangiocarcinoma (iCCA) has been newly subclassified into two different subtypes: large-duct (LD) type and small-duct (SD) type. However, many cases are difficult to subclassify, and there is no consensus regarding subclassification criteria. LD type expresses the highly sensitive diagnostic marker S100 calcium-binding protein P (S100P), while SD type lacks sensitive markers. We identified osteopontin (OPN) as a highly sensitive marker for SD type. This study aimed to develop new subclassification criteria for LD-type and SD-type iCCA. We retrospectively investigated 74 patients with iCCA and subclassified them based on whole-section immunostaining of S100P and OPN. Of the 74 cases, 41 were subclassified as LD type, 32 as SD type, and one was indeterminate. Notably, all S100P-negative cases had OPN positivity. Seventy-three of the 74 cases (98.6%) were clearly and easily subclassified as LD or SD type using only these 2 markers. We also determined the value of immunohistochemistry in cases that were difficult to diagnose based on hematoxylin-eosin and Alcian blue-periodic acid-Schiff staining. Furthermore, we analyzed the clinicopathological characteristics and prognoses of these 2 subtypes. LD type was a poor prognostic factor on univariate analysis; it had significantly worse overall survival ( P = 0.007) and recurrence-free survival ( P < 0.001) than the SD type. In conclusion, we propose new subclassification criteria for iCCA based on immunostaining of S100P and OPN. These criteria may help pathologists to diagnose subtypes of iCCA, supporting future clinical trials and the development of medications for these 2 subtypes as distinct cancers.


Assuntos
Neoplasias dos Ductos Biliares , Biomarcadores Tumorais , Proteínas de Ligação ao Cálcio , Colangiocarcinoma , Imuno-Histoquímica , Osteopontina , Humanos , Colangiocarcinoma/patologia , Colangiocarcinoma/classificação , Colangiocarcinoma/mortalidade , Colangiocarcinoma/química , Colangiocarcinoma/diagnóstico , Osteopontina/análise , Neoplasias dos Ductos Biliares/patologia , Neoplasias dos Ductos Biliares/classificação , Neoplasias dos Ductos Biliares/mortalidade , Neoplasias dos Ductos Biliares/química , Neoplasias dos Ductos Biliares/diagnóstico , Masculino , Feminino , Pessoa de Meia-Idade , Biomarcadores Tumorais/análise , Idoso , Estudos Retrospectivos , Proteínas de Ligação ao Cálcio/análise , Adulto , Idoso de 80 Anos ou mais , Proteínas de Neoplasias/análise , Valor Preditivo dos Testes , Ductos Biliares Intra-Hepáticos/patologia , Ductos Biliares Intra-Hepáticos/química
5.
Intern Med ; 63(8): 1105-1112, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-37779076

RESUMO

Cholangiocarcinoma has a poor prognosis, and resection is the only curative treatment. Pembrolizumab, a programmed death receptor 1 inhibitor, has proven effective against unresectable or metastatic solid tumors with high microsatellite instability (MSI-H) or a high tumor mutation burden (TMB-H). In the present case, pembrolizumab treatment was initiated after standard chemotherapy for MSI-H and TMB-H unresectable intrahepatic cholangiocarcinoma. Intrahepatic tumor necrosis perforated the abdominal cavity. Emergency surgery was performed, but the patient died 36 days after admission. A pathological autopsy revealed that the intrahepatic tumor had almost completely disappeared.


Assuntos
Anticorpos Monoclonais Humanizados , Antineoplásicos Imunológicos , Neoplasias dos Ductos Biliares , Colangiocarcinoma , Humanos , Instabilidade de Microssatélites , Antineoplásicos Imunológicos/uso terapêutico , Mutação , Colangiocarcinoma/tratamento farmacológico , Colangiocarcinoma/genética , Colangiocarcinoma/cirurgia , Biomarcadores Tumorais/genética , Ductos Biliares Intra-Hepáticos , Neoplasias dos Ductos Biliares/tratamento farmacológico , Neoplasias dos Ductos Biliares/genética , Neoplasias dos Ductos Biliares/cirurgia
6.
J Endod ; 2023 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-37595682

RESUMO

INTRODUCTION: Rheumatoid arthritis (RA) is an autoimmune disease that involves joint inflammation. Although periodontal disease reportedly contributes to RA onset, the associations of RA with pulpitis and apical periodontitis have not been described. The purpose of this study was to examine the effects of immune response disruption of RA for pulpitis and apical periodontitis with SKG mice. METHODS: SKG and BALB/c (control) mice were used to establish models of pulp infection. Histologic studies of pulp and apical periodontal tissue were performed at 3, 5, 7, 14, and 28 days; odontoblast dynamics were analyzed by antinestin staining, and apoptotic cells were examined by TdT-mediated digoxygenin (biotin)-dUTP nick end labeling staining. RESULTS: Inflammatory cell infiltration into the exposed pulp was observed at 3 days in the SKG and control group groups; the infiltration extended to the apical pulp area at 14 days after surgery. Inflammatory cell infiltration and bone resorption in the apical pulp area were observed from 14-28 days in the SKG and control groups; there were significant increases in inflammatory cell infiltration and bone resorption in the control group at 28 days. The numbers of apoptotic cells in pulp and apical periodontal tissue were higher in the SKG group than in the control group at 14 and 28 days. The number of odontoblasts decreased in the SKG and control groups until 14 days and then disappeared in the SKG and control groups at 28 days. CONCLUSIONS: This study suggested that immune response disruption in RA is involved in prolonging the inflammatory state of pulpitis and apical periodontitis.

7.
Asian J Surg ; 46(1): 431-437, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35610148

RESUMO

BACKGROUND: The aim of this study was to evaluate the safety of urgent laparoscopic cholecystectomy (Lap-C) for grade II acute cholecystitis (AC) in high-risk patients who were defined by Tokyo Guideline 18 as having age-adjusted Charlson comorbidity index ≥6 or American Society of Anesthesiologists physical status classification (ASA-PS) ≥ 3, compared with elective Lap-C following percutaneous transhepatic gallbladder drainage (PTGBD). METHODS: In 73 grade II AC patients who underwent Lap-C from January 2012 to March 2021, 35 were identified as high-risk; 22 underwent urgent Lap-C (urgent group) and 13 PTGBD followed by elective Lap-C (elective group). Surgical and perioperative outcomes were analyzed. RESULTS: There was no significant difference in operation time (median: 101 min vs 125 min; P = 0.371), blood loss (25 ml vs 7 ml; P = 0.853), morbidity rate (31.8% vs 38.5%; P = 0.726), or the incidence of total perioperative major complications (13.6% vs 15.4%; P = 1.000) between the two groups. The total duration of treatment was significantly shorter in the urgent group than the elective group (11 days vs 71 days; P < 0.001). Multivariate analysis revealed that blood loss ≥45 ml [odds ratio (OS): 12.14, 95% confidence interval (CI): 2.03-72.42, P = 0.006], and age ≥75 years with ASA-PS ≥ 3 (OS: 9.85, 95%CI: 1.26-77.26, P = 0.03) were the independent risk factors for total perioperative major complications. CONCLUSION: In well-selected high-risk patients with grade II AC, urgent Lap-C can be performed with comparable safety to elective Lap-C following PTGBD.


Assuntos
Colecistectomia Laparoscópica , Colecistite Aguda , Colecistostomia , Humanos , Idoso , Drenagem , Colecistite Aguda/cirurgia , Resultado do Tratamento , Estudos Retrospectivos
8.
Surg Case Rep ; 8(1): 132, 2022 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-35831765

RESUMO

BACKGROUND: Liver metastasis is the most common form of distant spread of colorectal cancer. Despite oncological and surgical advances, only about 25% of patients are eligible to undergo resection. As the liver has a limited resectable volume, tumor reduction and remnant liver hypertrophy are of critical importance in treating initially unresectable colorectal cancer liver metastasis. Associated liver partition and portal vein ligation for staged hepatectomy (ALPPS) allows rapid liver hypertrophy within a short period and has been reported to be useful in recent years. CASE PRESENTATION: A 29-year-old woman complaining of bloody stool was referred to our hospital. She was diagnosed with rectal cancer (Rb) with simultaneous multiple liver and lung metastases. The patient was then initially commenced on chemotherapy and completed it with a satisfactory response. Right trisectionectomy was necessary to achieve hepatic clearance; however, the future liver remnant (FLR) volume was insufficient. Therefore, we decided to perform totally laparoscopic ALPPS to obtain enough FLR volume. However, the FLR increase was slow, and FLR did not attain the required volume for right trisectionectomy. Computed tomography showed that right portal venous blood flow was increased via developed collateral vessels around the portal vein. We attempted to induce further liver growth by blocking portal blood flow using additional percutaneous transhepatic portal vein embolization (PTPE), and a rapid increase in FLR was obtained. The patient underwent right trisectionectomy and partial resection of S2 with negative margins, and the patient was discharged without postoperative liver failure. CONCLUSIONS: Resumption of the portal venous blood flow through collateral vessels after ALPPS may have interfered with the planned residual liver hypertrophy. Performing PTPE in addition to ALPPS increased the FLR volume, and radical hepatectomy was completed safely. Remnant portal venous blood flow following ALPPS is an important issue to be considered in surgical planning, and early additional portal vein embolization could be effective.

9.
World J Gastroenterol ; 28(6): 675-682, 2022 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-35317428

RESUMO

BACKGROUND: Malignant lymphoma is a rare form of gallbladder malignancy. Most of these malignancies are diffuse large B-cell lymphomas or mucosa-associated lymphoid tissue-type lymphomas; however, Burkitt's lymphoma of the gallbladder is extremely rare, and only two previous reports are available in the literature. Herein, we report a rare case of Burkitt's lymphoma of the gallbladder mimicking gallbladder adenocarcinoma. CASE SUMMARY: An 83-year-old man with no abdominal complaints was found to have a gallbladder tumor and periportal lymph node enlargement on computed tomography (CT) performed for hypertension screening. His laboratory data revealed slightly elevated serum levels of carcinoembryonic antigen and soluble interleukin 2 receptor. Imaging examinations revealed two irregular and contrast-enhanced masses extending into the gallbladder lumen, but these did not infiltrate the serosa. Moreover, a periportal lymph node had enlarged to 30 mm. Based on these findings, we diagnosed the patient as having gallbladder adenocarcinoma with lymph node metastasis, which was treated using bile duct resection with gallbladder bed resection and periportal lymph node dissection. However, the patient was finally diagnosed as having Burkitt's lymphoma. Although the surgical margin was pathologically negative, recurrence was noted at the hepatic radical margin and superior pancreaticoduodenal lymph nodes on positron emission tomography/CT soon after discharge. Thus, he was referred to a hematologist and started receiving treatment with reduced-dose cyclophosphamide, doxorubicin, vincristine, and prednisone. CONCLUSION: Burkitt's lymphoma can occur in the gallbladder. Biopsy can be useful in cases with findings suggestive of gallbladder malignant lymphoma.


Assuntos
Linfoma de Burkitt , Neoplasias da Vesícula Biliar , Idoso de 80 Anos ou mais , Linfoma de Burkitt/diagnóstico , Linfoma de Burkitt/cirurgia , Colecistectomia , Neoplasias da Vesícula Biliar/diagnóstico , Neoplasias da Vesícula Biliar/patologia , Neoplasias da Vesícula Biliar/cirurgia , Humanos , Metástase Linfática , Masculino
10.
Pathol Res Pract ; 232: 153832, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35287087

RESUMO

Leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5) is a known cancer stem cell marker. However, there are no reported analyses of LGR5 mRNA expression in normal liver and liver cancer tissues. Here, we evaluated LGR5 expression by RNAscope, a newly developed RNA in situ hybridization technique, using a tissue microarray consisting of 25 samples of intrahepatic cholangiocarcinoma (ICC) selected from the medical archives at our hospital. LGR5 expression levels were divided into high and low expression groups by the five-grade scoring system, and clinicopathological features were analyzed. Low LGR5 expression was identified in some normal hepatocytes and bile duct cells. In addition, LGR5 expression was identified in all bile duct cancer samples except one case. Well-differentiated to moderately-differentiated adenocarcinoma tended to show higher LGR5 expression than poorly-differentiated adenocarcinoma (P = 0.0561), and the large duct type showed significantly higher LGR5 expression levels than the small duct type (P = 0.0225). Patients in the high LGR5 expression group tended to have good overall survival (OS) (P = 0.0623). The Cox proportional hazard regression model revealed that the high LGR5 expression group showed independently better OS for ICC (P = 0.0285). High LGR5 expression is possibly a good prognosis factor in ICC. However, the detailed mechanism of LGR5 in this disease remains unclear, and further analysis is warranted.


Assuntos
Adenocarcinoma , Neoplasias dos Ductos Biliares , Colangiocarcinoma , Adenocarcinoma/patologia , Ductos Biliares Intra-Hepáticos/patologia , Humanos , Prognóstico , Receptores Acoplados a Proteínas G/genética
11.
J Surg Case Rep ; 2022(2): rjac005, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35145622

RESUMO

Colocutaneous fistula associated with Crohn's disease after mesh repair for inguinal hernia has not been previously reported in the literature. We report such case in an 83-year-old man following a preperitoneal repair of a left-sided inguinal hernia using Kugel patch. The patient has Crohn's disease in remission status for 4 years. One month after inguinal hernia repair, he presented with fever and left-sided inguinal pain and swelling. Computed tomography revealed abscess formation in the preperitoneal and subcutaneous space of the left-sided inguinal region. Colonoscopy showed local exacerbation of Crohn's disease in the sigmoid colon, and formation of fistula between the sigmoid colon and abdominal wall of the left-sided inguinal region. We performed mesh removal with Hartmann resection following percutaneous abscess drainage. The post-operative course was uneventful, and no sign of recurrence of the hernia was found for 3 years post-operatively.

12.
Ann Surg Oncol ; 29(2): 1437-1448, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34664139

RESUMO

BACKGROUND: Although various biomarkers are useful in predicting cancer prognosis, the most effective preoperative systemic biomarkers for pancreatic ductal adenocarcinoma (PDAC) have not been established. This study aimed to evaluate whether the lymphocyte-to-monocyte ratio (LMR) can predict the long-term outcomes for patients who were to undergo surgical resection of PDAC. METHODS: The study involved 170 patients with PDAC who underwent resection. Multivariate analysis was performed to identify the independent prognostic factors for overall survival (OS) and disease-free survival (DFS) among clinicopathologic, surgical, and seven systemic biomarker-related factors including LMR. Subgroup analysis of PDAC located in the body and tail of the pancreas (B/T PDAC) was performed (n = 60) to eliminate the influence of preoperative cholangitis and surgical procedure. Furthermore, OS according to the postoperative course of the LMR value group was investigated. RESULTS: A low LMR (<3.3) was the only independent predictive factor for OS (hazard ratio [HR], 3.52; p < 0.001) and DFS (HR, 3.31; p < 0.001) among the systemic biomarkers. Subgroup analysis of the B/T PDAC also showed that low the LMR was the independent predictive factor for OS (HR, 3.24; p = 0.002) and DFS (HR, 4.42; p = 0.003). The PDAC that maintained a high LMR from before surgery to 1 year after surgery showed good long-term outcomes (median OS, 8.5 years; 5-year survival rate, 61.8 %). CONCLUSIONS: Preoperative LMR was an independent predictor of OS and DFS after surgery for PDAC. Maintaining a high LMR through the pre- and postoperative courses might improve the prognosis for patients with PDAC.


Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Carcinoma Ductal Pancreático/cirurgia , Humanos , Linfócitos , Monócitos , Neoplasias Pancreáticas/cirurgia , Prognóstico , Estudos Retrospectivos
13.
Ann Thorac Surg ; 114(1): 257-264, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-34389301

RESUMO

BACKGROUND: The necessity of thoracic epidural analgesia (TEA) during minimally invasive surgery (MIS) remains unclear. We investigated TEA efficacy in MIS versus thoracotomy and the noninferiority of a preemptive intercostal nerve block (ICNB) to TEA in MIS. METHODS: We investigated 393 patients who underwent lung resection, with and without TEA, between 2014 and 2019 (242 MIS, 151 thoracotomy) and 93 patients who underwent MIS with ICNB between 2019 and 2020. To address selection bias 70 TEA and 70 ICNB patients were propensity score matched. Endpoints were pain score during hospitalization, postoperative complications, duration of operating room use, analgesia-related adverse effects, and use of supplemental pain medication. RESULTS: One-third of patients with MIS discontinued TEA on postoperative day 1 or earlier; those with early TEA discontinuation reported worse pain the next day. TEA was associated with lower pain scores compared with non-TEA, regardless of surgical invasiveness, and a lower complication risk in patients with thoracotomy but not MIS. For MIS, ICNB was associated with an equivalent pain score on postoperative day 1, lower average pain score during hospitalization, shorter duration of operation room use, less frequent use of supplemental pain medication, and similar risk of postoperative complication and analgesia-related adverse effects compared with TEA after matching. CONCLUSIONS: Given early TEA discontinuation after MIS and ICNB's noninferior pain relief, preemptive ICNB can be an alternative for TEA in patients undergoing MIS.


Assuntos
Analgesia Epidural , Humanos , Nervos Intercostais , Manejo da Dor , Dor Pós-Operatória/tratamento farmacológico , Toracotomia/efeitos adversos
14.
Surg Open Sci ; 6: 1-4, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34355156

RESUMO

BACKGROUND: Perforated appendicitis without an associated abscess necessitates emergency surgery. However, it is difficult to predict the presence of perforation before surgery, and the predictive factors are still unclarified. Our purposes were to characterize a patient population with perforated appendicitis without an associated abscess to identify the preoperative predictive factors of appendiceal perforation. METHODS: We retrospectively identified 150 patients who underwent appendectomy for acute appendicitis at our institution from June 2018 to November 2020. Logistic regression analysis was performed to analyze the concurrent effects of various factors on the prevalence of perforated appendicitis. RESULTS: Forty (29%) of 150 patients had appendiceal perforation detected intraoperatively. Of these 40 patients, only 19 had appendiceal perforation detected on preoperative computed tomography. Multivariable analysis found that a higher C-reactive protein level, higher total bilirubin level, and the presence of an appendiceal fecalith were independent predictive factors for appendicitis with perforation. CONCLUSION: Our analysis suggests that the presence of an appendiceal fecalith, a total bilirubin level of more than 21.38 µmol/L, and a C-reactive protein level of more than 3.0 × 104 µg/L are predictive factors of perforated appendicitis.

16.
Am J Case Rep ; 22: e931114, 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33844677

RESUMO

BACKGROUND Protein-losing enteropathy as a complication of superior mesenteric artery occlusion is extremely rare and severe, and sometimes requires intestinal resection. However, the ideal treatment strategy has not yet been determined. CASE REPORT A 77-year-old man with underlying hypertension and diabetes was admitted to the Emergency Department with acute abdominal pain after eating. Contrast-enhanced computed tomography revealed complete occlusion of the superior mesenteric artery with thrombosis, and superior mesenteric artery occlusion was diagnosed. It was successfully treated with interventional therapy, followed by continuous intra-arterial prostaglandin E1 infusion and continuous intravenous heparin infusion. However, the patient developed hypoproteinemia and diarrhea about 10 days after the interventional therapy. Colonoscopy and X-ray studies did not reveal any abnormal findings; however, technetium-99m-labeled human serum albumin scintigraphy indicated protein-losing enteropathy. With total parenteral nutrition and protein-rich oral nutrition, with protein intake at twice the amount in a standard diet, serum albumin improved from 15 g/L to 32 g/L after treatment. Additionally, we administered diuretics to avoiding edema related to the hypoproteinemia. The patient recovered from the hypoproteinemia and diarrhea without complications. CONCLUSIONS Protein-losing enteropathy is an extremely rare but critical complication of superior mesenteric artery occlusion. Treating the underlying pathology is the mainstay of protein-losing enteropathy and dietary modifications also play a critical role. Our patient was successfully treated with strict nutritional therapy, combined oral protein-rich nutrition and total parenteral nutrition, which avoided surgery.


Assuntos
Hipoproteinemia , Oclusão Vascular Mesentérica , Enteropatias Perdedoras de Proteínas , Idoso , Humanos , Masculino , Artéria Mesentérica Superior/diagnóstico por imagem , Artéria Mesentérica Superior/cirurgia , Enteropatias Perdedoras de Proteínas/diagnóstico por imagem , Enteropatias Perdedoras de Proteínas/etiologia , Enteropatias Perdedoras de Proteínas/terapia , Cintilografia
17.
J Phys Chem B ; 121(35): 8291-8299, 2017 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-28762739

RESUMO

Redox active cofactors play a dynamic role inside protein binding active sites because the amino acids responsible for binding participate in electron transfer (ET) reactions. Here, we use femtosecond transient absorption (FsTA) spectroscopy to examine the ultrafast ET between quinacrine (Qc), an antimalarial drug with potential anticancer activity, and riboflavin binding protein (RfBP) with a known Kd = 264 nM. Steady-state absorption reveals a ∼ 10 nm red-shift in the ground state when QcH32+ is titrated with RfBP, and a Stern-Volmer analysis shows ∼84% quenching and a blue-shift of the QcH32+ photoluminescence to form a 1:1 binding ratio of the QcH32+-RfBP complex. Upon selective photoexcitation of QcH32+ in the QcH32+-RfBP complex, we observe charge separation in 7 ps to form 1[QcH3_red•+-RfBP•+], which persists for 138 ps. The FsTA spectra show the spectroscopic identification of QcH3_red•+, determined from spectroelectrochemical measurements in DMSO. We correlate our results to literature and report lifetimes that are 10-20× slower than the natural riboflavin, Rf-RfBP, complex and are oxygen independent. Driving force (ΔG) calculations, corrected for estimated dielectric constants for protein hydrophobic pockets, and Marcus theory depict a favorable one-electron ET process between QcH32+ and nearby redox active tyrosine (Tyr) or tryptophan (Trp) residues.


Assuntos
Proteínas de Membrana Transportadoras/química , Quinacrina/química , Técnicas Eletroquímicas , Transporte de Elétrons , Estrutura Molecular , Análise Espectral , Termodinâmica
18.
Dalton Trans ; 41(17): 5343-50, 2012 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-22451041

RESUMO

We report the synthesis, structure and properties of the cyanide-bridged dinuclear complex ions [Ru(L)(bpy)(µ-NC)M(CN)(5)](2-/-) (L = tpy, 2,2';6',2''-terpyridine, or tpm, tris(1-pyrazolyl)methane, bpy = 2,2'-bipyridine, M = Fe(II), Fe(III), Cr(III)) and the related monomers [Ru(L)(bpy)X](2+) (X = CN(-) and NCS(-)). All the monomeric compounds are weak MLCT emitters (λ = 650-715 nm, ϕ ≈ 10(-4)). In the Fe(II) and Cr(III) dinuclear systems, the cyanide bridge promotes efficient energy transfer between the Ru-centered MLCT state and a Fe(II)- or Cr(III)-centered d-d state, which results either in a complete quenching of luminescence or in a narrow red emission (λ ≈ 820 nm, ϕ ≈ 10(-3)) respectively. In the case of Fe(III) dinuclear systems, an electron transfer quenching process is also likely to occur.

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