861 research outputs found
Metabolic labelling of cholesteryl glucosides in Helicobacter pylori reveals how the uptake of human lipids enhances bacterial virulence.
Helicobacter pylori infects approximately half of the human population and is the main cause of various gastric diseases. This pathogen is auxotrophic for cholesterol, which it converts upon uptake to various cholesteryl α-glucoside derivatives, including cholesteryl 6'-acyl and 6'-phosphatidyl α-glucosides (CAGs and CPGs). Owing to a lack of sensitive analytical methods, it is not known if CAGs and CPGs play distinct physiological roles or how the acyl chain component affects function. Herein we established a metabolite-labelling method for characterising these derivatives qualitatively and quantitatively with a femtomolar detection limit. The development generated an MS/MS database of CGds, allowing for profiling of all the cholesterol-derived metabolites. The subsequent analysis led to the unprecedented information that these bacteria acquire phospholipids from the membrane of epithelial cells for CAG biosynthesis. The resulting increase in longer or/and unsaturated CAG acyl chains helps to promote lipid raft formation and thus delivery of the virulence factor CagA into the host cell, supporting the idea that the host/pathogen interplay enhances bacterial virulence. These findings demonstrate an important connection between the chain length of CAGs and the bacterial pathogenicity
Relationships between serum HER2 ECD, TIMP-1 and clinical outcomes in Taiwanese breast cancer
<p>Abstract</p> <p>Background</p> <p>Serum levels of the extracellular domain of HER2/neu (HER2 ECD) have been demonstrated to be associated with clinical outcomes. A disintegrin and metalloproteinase-10, a sheddase of HER2/neu, can drive cancer progression and its activity is inhibited by tissue inhibitor of metalloproteinase-1 (TIMP-1). However, elevated TIMP-1 expression has been associated with a poor prognosis of breast cancer. Therefore, this study was performed to explore the relationships between serum HER2 ECD, TIMP-1 and clinical outcomes.</p> <p>Methods</p> <p>One hundred and eighty-five female breast cancer patients, who received curative mastectomy without neo-adjuvant chemotherapy at Chang-Gung Memorial Hospital, were recruited with informed consent for this study. Pre-operative serum levels of HER2 ECD and TIMP-1 were measured using an enzyme-linked immunosorbent assay.</p> <p>Results</p> <p>Twenty-three cases (12.4%) were classified HER2 ECD positive. HER2 ECD positivity was significantly associated with age, lymph node involvement, histological grade, estrogen receptor status, progesterone receptor status, tissue HER2/neu overexpression, and disease-free survival (DFS). In an age, stage, ER and HER2/neu status matched subgroup (N = 41), the serum level of TIMP-1 was significantly associated with HER2 ECD positivity and DFS.</p> <p>Conclusions</p> <p>A high serum TIMP-1 was significantly associated with HER2 ECD positivity and a poorer DFS among Taiwanese primary breast cancer patients with HER2 overexpression.</p
Prognosis of ductal adenocarcinoma of pancreatic head with overexpression of CD44
SummaryBackgroundThe long-term survival rate of patients with pancreatic ductal adenocarcinoma (PDAC) is very low. Cancer stem cells have been identified in PDAC based on the expression of the surface markers CD24, CD44, CD133, and epithelial specific antigen. The prognosis of PDAC may be related to the presence or absence of tumor cells with cancer stem cell surface markers.MethodsEighty-six PDAC patients (51 male and 35 female patients) who underwent surgical treatment at Chang Gung Memorial Hospital—Lin-Kou Medical Center, Lin-Kou, Taiwan between 1998 and 2007 were included in this study. The patients' ages ranged from 30 years to 84 years. All their surgical specimens showed invasive ductal cancer. Immunohistochemical staining with CD44 antibodies was performed. The differences in clinical data, cell types of tumors, tumor staging, and survival rates between patients with CD44− (Group A; n = 33) and CD44+ (Group B; n = 53) were compared.ResultsClinical data, cell types of tumors, and tumor staging between the two groups showed no significant differences. The 3- and 5-year survival rates were, respectively, 51.5% and 19.8% in patients with CD44− tumor cells and 4.0% and 2.0% in those with CD44+ tumor cells. The differences were statistically significant (p < 0.0001). The median overall survival times of the two groups were also different (36.9 months vs. 12.2 months, p < 0.0001). Multivariate analysis showed that the CD44 as well as lymph node status, and differentiation of tumor cells were prognostic factors for patients with PDAC.ConclusionThe results suggested that CD44 expression in patients with PDAC after surgery was significantly associated with decreased survival, whereas patients with CD44− tumor cells survived significantly longer
Clinicopathologic features and outcomes following surgery for pancreatic adenosquamous carcinoma
<p>Abstract</p> <p>Background</p> <p>Pancreatic adenosquamous carcinoma (ASC) is a rare pancreatic malignancy subtype. We investigated the clinicopathological features and outcome of pancreatic ASC patients after surgery.</p> <p>Methods</p> <p>The medical records of 12 patients with pancreatic ASC undergoing surgical treatment (1993 to 2006) were retrospectively reviewed. Survival data of patients with stage IIB pancreatic adenocarcinoma and ASC undergoing surgical resection were compared.</p> <p>Results</p> <p>Symptoms included abdominal pain (91.7%), body weight loss (83.3%), anorexia (41.7%) and jaundice (25.0%). Tumors were located at pancreatic head in 5 (41.7%) patients, tail in 5 (41.7%), and body in 4 (33.3%). Median tumor size was 6.3 cm. Surgical resection was performed on 7 patients, bypass surgery on 3, and exploratory laparotomy with biopsy on 2. No surgical mortality was identified. Seven (58.3%) and 11 (91.7%) patients died within 6 and 12 months of operation, respectively. Median survival of 12 patients was 4.41 months. Seven patients receiving surgical resection had median survival of 6.51 months. Patients with stage IIB pancreatic ASC had shorter median survival compared to those with adenocarcinoma.</p> <p>Conclusion</p> <p>Aggressive surgical management does not appear effective in treating pancreatic ASC patients. Strategies involving non-surgical treatment such as chemotherapy, radiotherapy or target agents should be tested.</p
Isolated pancreatic metastasis from rectal cancer: a case report and review of literature
Isolated pancreatic metastases from a non-pancreatic primary malignancy are very rare. Studies have shown that resection of metastases is of proven benefit in some types of tumors. We report a case of 76-year-old Taiwanese woman with rectal adenocarcinoma treated with neoadjuvant chemoradiotherapy and abdominoperineal resection 2 years ago presenting with an asymptomatic mass at the pancreatic tail on a routine follow up abdominal computed tomography scan. The patient underwent distal pancreatectomy and splenectomy under the preoperative impression of a primary pancreatic malignancy. Histological examination of the surgical specimen showed metastatic adenocarcinoma. Immunohistochemical studies confirmed the diagnosis of pancreatic metastasis from rectal adenocarcinoma. Postoperative chemotherapy in the form of oral capecitabine was given. The patient is alive and disease free 12 months after the surgery. In a patient presenting with a pancreatic mass with history of a non-pancreatic malignancy, a differential diagnosis of pancreatic metastasis should be considered. Surgical resection of a solitary pancreatic mass is justified not only to get the definitive diagnosis but also to improve the survival
Computational analysis of a novel mutation in ETFDH gene highlights its long-range effects on the FAD-binding motif
<p>Abstract</p> <p>Background</p> <p>Multiple acyl-coenzyme A dehydrogenase deficiency (MADD) is an autosomal recessive disease caused by the defects in the mitochondrial electron transfer system and the metabolism of fatty acids. Recently, mutations in electron transfer flavoprotein dehydrogenase (<it>ETFDH</it>) gene, encoding electron transfer flavoprotein:ubiquinone oxidoreductase (ETF:QO) have been reported to be the major causes of riboflavin-responsive MADD. To date, no studies have been performed to explore the functional impact of these mutations or their mechanism of disrupting enzyme activity.</p> <p>Results</p> <p>High resolution melting (HRM) analysis and sequencing of the entire <it>ETFDH </it>gene revealed a novel mutation (p.Phe128Ser) and the hotspot mutation (p.Ala84Thr) from a patient with MADD. According to the predicted 3D structure of ETF:QO, the two mutations are located within the flavin adenine dinucleotide (FAD) binding domain; however, the two residues do not have direct interactions with the FAD ligand. Using molecular dynamics (MD) simulations and normal mode analysis (NMA), we found that the p.Ala84Thr and p.Phe128Ser mutations are most likely to alter the protein structure near the FAD binding site as well as disrupt the stability of the FAD binding required for the activation of ETF:QO. Intriguingly, NMA revealed that several reported disease-causing mutations in the ETF:QO protein show highly correlated motions with the FAD-binding site.</p> <p>Conclusions</p> <p>Based on the present findings, we conclude that the changes made to the amino acids in ETF:QO are likely to influence the FAD-binding stability.</p
Correlating Chemical Reaction and Mass Transport in Hydrogen-based Direct Reduction of Iron Oxide
Steelmaking contributes 8% to the total CO2 emissions globally, primarily due
to coal-based iron ore reduction. Clean hydrogen-based ironmaking has variable
performance because the dominant gas-solid reduction mechanism is set by the
defects and pores inside the mm-nm sized oxide particles that change
significantly as the reaction progresses. While these governing dynamics are
essential to establish continuous flow of iron and its ores through reactors,
the direct link between agglomeration and chemistry is still contested due to
missing measurements. In this work, we directly measure the connection between
chemistry and agglomeration in the smallest iron oxides relevant to magnetite
ores. Using synthesized spherical 10-nm magnetite particles reacting in H2, we
resolve the formation and consumption of w\"ustite (FeO) - the step most
commonly attributed to agglomeration. Using X-ray scattering and microscopy, we
resolve crystallographic anisotropy in the rate of the initial reaction, which
becomes isotropic as the material sinters. Complementing with imaging, we
demonstrate how the particles self-assemble, subsequently react and sinter into
~100x oblong grains. Our insights into how morphologically uniform iron oxide
particles react and agglomerate H2 reduction enable future size-dependent
models to effectively describe the multiscale iron ore reduction
Transmission of acute infectious illness among cases of Kawasaki disease and their household members
Background/purposeKawasaki disease (KD) is a disease of unknown cause and the causative agent is most likely to be infectious in nature. To investigate the household transmission pattern of infectious illness and etiology, we thus initiated a prospective case and household study.MethodsWe enrolled KD cases and their household members from February 2004 to September 2008. The KD cases and their household members accepted questionnaire-based interviews of the contact history, signs of infection, and symptoms to check whether clusters of infectious illness occurred.ResultsA total of 142 KD cases and 561 household members were enrolled. Among the 142 KD cases, 136 cases (96%) were typical KD, and six (4%) were atypical KD. Of the 561 household members, 17% were siblings, 46% were parents, 18% were grandparents, and the others were cousins or babysitters. Prior to the onset of their KD illness, 66% (94/142) KD cases had contact with ill household members. On the same day of the onset of KD cases' illness, 4% (6/142) KD cases had household members with illness. After KD cases' disease onset, 70% (100/142) KD cases had at least one other family member with illness. Overall, 61% (343/561) of all the household members had acute infectious illness during KD cases' acute stage, and 92% (130/142) of the families had clusters of infectious illness.ConclusionA total of 66% KD cases had positive contact with ill household members prior to their disease onset and 92% of families had clusters of infectious illness, so KD is strongly associated with infections
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