Alternating bolus and continuous infusion 5-fluorouracil: a strategy to overcome resistance to this fluoropyrimidine in advanced colorectal cancer patients

Focusing our effort on the importance of FUra scheduling we have tested the hypothesis that pulse and continuous infusion (CI) of the fluoropyrimidine have different mechanisms of cytotoxicity. Our initial approach was to compare the mechanism of resistance of a cell line resistant to a short term exposure to FUra (HCT-8/FU4hR) to that of a cell line resistant to a prolonged exposure to the fluoropyrimidine (HCT-8/FU7dR). Cytotoxicity studies showed that HCT-8/FU4hR cells were still sensitive to FUra given as a 7-d exposure, suggesting different mechanisms of resistance. Indeed, rapid recovery of TS activity after drug removal was evident in the HTC-8/FU7dR cell line while HCT-8/FU4hR cells were similar to the parental cell line with regard to both the degree of in situ TS inhibition by FUra and duration of inhibition after FUra removal. In contrast, labelling studies with [³H-6] FUra (4 h exposure, 100 M) showed that the incorporation of the fluoropyrimidine into RNA is significantly decreased in HCT-8/FU4hR cells as compared to parental HCT-8 cells.Given the lack of cross resistance between the two schedulesin vitro, a pilot trial was done on patients with colorectal cancer refractory to bolus FUra. On 15 patients failing after FUra+LV or FUra alone 1 PR, 3 MR, 3 SD and 8 P were observed, confirmng a certain degree of activity of CI FUra in patients clinically resistant to bolus FUra.Based on this rationale, a phase II trial of schedule-oriented biochemical modulation of FUra in advanced colorectal cancer patients was conducted, employing a hybrid regimen of 2 biweekly cycles of FUra bolus (600 mg/sqm), preceeded by (24 h interval) methotrexate, 200 mg/sqm (in order to maximize the RNA effect of the drug) alternating with FUra continuous infusion, 200 mg/sqm daily for 3 weeks, modulated by leucovorin, 20 mg/sqm weekly bolus (in order to maximize the DNA effect).Thirty-three consecutive patients (median ECOG PS 1) with advanced measurable colorectal cancer and no prior therapy for metastatic disease entered the study, from February 1992 to August 1993. Three complete and 13 partial responses were obtained among these 33 patients (RR=48%, 95% confidence limis, 31–66%). After a median follow-up time of 23 months, 16 patients are still alive. The median progression free survival and overall survival were 9.6 and 20.8 months, respectively. No toxic deaths or grade 4 toxicity occurred. The incidence of grade 3 toxicity per patient in any cycle was: mucositis 6%, diarrhea 3% and vomiting 3% for the bolus part and 21%, 3% and 6% respectively, for the continuous infusion part of the regimen. Hand-foot syndrome occurred in 27% of the patients treated with the continuous infusion regimen.In conclusion, this experimental and clinical project has generated a novel regimen of schedule oriented biochemical modulation that is twice as active and half as toxic compared to bolus FU+LV given with either the daily x 5 or the weekly schedule. This high clinical activity is very encouraging, especially considering that 1) consecutive patients were entered, 2) the responses were independently reviewed, 3) the progression free survival and survival were much longer than those actually reported for this disease, 4) the toxicity of the program, in particular the bolus regimen, was relatively low allowing further intensification.     

Effects of glycated albumin on mesangial cells: evidence for a role in diabetic nephropathy

Nonenzymatically glycated proteins are preferentially transported across the glomerular filtration barrier, and the glomerular mesangium in diabetes is bathed with serum containing increased concentrations of glycated albumin. We investigated effects of glycated albumin on mesangial cells, which are involved in diabetic nephropathy. [³H]-thymidine incorporation was significantly inhibited when murine mesangial cells were grown in culture media containing human serum that had been nonenzymatically glycated by incubation for 4 days with 28 mM glucose. This inhibition was reversed when monoclonal antibodies that selectively react with Amadori products of glycated albumin were added to the culture media. Purified glycated albumin containing Amadori adducts of the glycation reaction induced significant inhibition of thymidine incorporation and stimulation of Type IV collagen secretion compared with cells cultured in the presence of purified nonglycated albumin. These changes were prevented when monoclonal antibodies specifically reactive with fructosyl-lysine epitopes in glycated albumin were added to the cultures. The antibodies had no effect on growth or collagen production in the presence of nonglycated albumin. The results provide the first evidence directly implicating Amadori adducts in glycated albumin in the pathogenesis of diabetic nephropathy, which is characterized by decreased cellularity in association with expansion of the mesangial matrix.     

Flavonols and C-Glycosylflavonoids of the caryophyllales

A survey of 112 species of the Caryophyllales showed the presence of flavonols in all eleven families and of C-glycosylflavonoids in nine families, being absent from the Aizoaceae and Cactaceae. 18% of the species contained both classes of compound. C-glycosylflavonoids are reported for the first time in the Amaranthaceae, Basellaceae, Didieraceae, Nyctaginaceae, Phytolaccaceae, Portulacaceae and Molluginaceae. The Caryophyllaceae contained prodominantly C-glycosylflavonoids, suggesting they are the most advanced family in the order.     

Loganin alleviates testicular damage and germ cell apoptosis induced by AGEs upon diabetes mellitus by suppressing the RAGE/p38MAPK/NF-κB pathway

Diabetes mellitus (DM) damages male reproduction at multiple levels, such as endocrine secretion, spermatogenesis and penile erection. We herein investigated the protective effects and mechanism of loganin targeting the advanced glycation end products (AGEs)/receptor for AGEs (RAGE)/p38 mitogen-activated protein kinase (p38MAPK)/NF-κB signalling pathway. Loganin relieved the general DM symptoms and decreased the blood glucose level of KK-Ay DM mice. Haematoxylin-eosin staining demonstrated that loganin ameliorated testicular histology and function and enhanced the activities of testis-specific markers lactate dehydrogenase (LDH), acid phosphatase (ACP) and gamma-glutamyl transferase (γ-GT). Loganin also showed evident anti-oxidative stress, anti-apoptotic and anti-inflammatory effects on DM-induced reproductive damage by restoring glutathione (GSH) level and superoxide dismutase (SOD) activity, as well as reducing reactive oxygen species (ROS) level and Bax/Bcl-2 ratio in vivo and in vitro. Western blotting exhibited that loganin significantly inhibited the AGEs/RAGE/p38MAPK/NF-κB signalling pathway. Acridine orange and ethidium bromide staining (AOEB) and Western blotting showed that loganin in combination with inhibitors of RAGE, p38MAPK and NF-κB exerted stronger anti-apoptotic effects on AGE-induced GC-2 cell damage compared with loganin alone. In conclusion, loganin can protect against DM-induced reproductive damage, probably by suppressing the AGEs/RAGE/p38MAPK/NF-κB pathway.     

腹腔镜结肠癌根治术治疗老年局部进展期结肠癌的疗效和安全性及对患者免疫功能的影响

目的:比较分析腹腔镜和开腹结肠癌根治术治疗老年局部进展期结肠癌的临床疗效和安全性及对患者免疫功能的影响。方法:根据随机数字表法,将64例老年局部进展期结肠癌患者随机分为腹腔镜组和开腹组,每组各32例,分别接受腹腔镜、开腹结肠癌根治术治疗。比较两组手术相关指标、手术前后免疫功能变化、术后近远期并发症的发生情况及预后。结果:与开腹组比较,腹腔镜组患者手术时间明显延长,而术中出血量、胃肠功能恢复时间则明显缩短(P<0.05)。两组淋巴结清扫数比较差异无统计学意义(P>0.05)。术后3个月,腹腔镜组CD4+、CD4+/CD8+比值均明显高于开腹组(P<0.05),且与术前比较差异均无统计学意义(P>0.05)。与开腹组比较,腹腔镜组患者术后切口感染的发生率明显降低(P<0.05),两组其他近期并发症如吻合口瘘、吻合口出血,远期并发症如黏连性肠梗阻、切口疝的发生率比较差异均无统计学意义(P>0.05)。腹腔镜组与开腹组术后2年的局部复发率、1年和2年生存率比较差异均无统计学意义(P>0.05)。结论:腹腔镜手术和开腹手术治疗老年局部进展期结肠癌患者的临床疗效和预后相当,但腹腔镜手术对患者的免疫功能影响更小,且安全性更高。     

Straw utilization for biofuel production: A consequential assessment of greenhouse gas emissions from bioethanol and biomethane provision with a focus on the time dependency of emissions

The shift from straw incorporation to biofuel production entails emissions from production, changes in soil organic carbon (SOC) and through the provision of (co‐)products and entailed displacement effects. This paper analyses changes in greenhouse gas (GHG) emissions arising from the shift from straw incorporation to biomethane and bioethanol production. The biomethane concept comprises comminution, anaerobic digestion and amine washing. It additionally provides an organic fertilizer. Bioethanol production comprises energetic use of lignin, steam explosion, enzymatic hydrolysis and co‐fermentation. Additionally, feed is provided. A detailed consequential GHG balance with in‐depth focus on the time dependency of emissions is conducted: (a) the change in the atmospheric load of emissions arising from the change in the temporal occurrence of emissions comparing two steady states (before the shift and once a new steady state has established); and (b) the annual change in overall emissions over time starting from the shift are assessed. The shift from straw incorporation to biomethane production results in net changes in GHG emissions of (a) ?979 (?436 to ?1,654) and (b) ?955 (?220 to ?1,623) kg CO₂‐eq. per t_{dry matter} straw converted to biomethane (minimum and maximum). The shift to bioethanol production results in net changes of (a) ?409 (?107 to ?610) and (b) ?361 (57 to ?603) kg CO₂‐eq. per t_{dry matter} straw converted to bioethanol. If the atmospheric load of emissions arising from different timing of emissions is neglected in case (a), the change in GHG emissions differs by up to 54%. Case (b) reveals carbon payback times of 0 (0–49) and 19 (1–100) years in case of biomethane and bioethanol production, respectively. These results demonstrate that the detailed inclusion of temporal aspects into GHG balances is required to get a comprehensive understanding of changes in GHG emissions induced by the introduction of advanced biofuels from agricultural residues.     

Thymol alleviates AGEs-induced podocyte injury by a pleiotropic effect via NF-κB-mediated by RhoA/ROCK signalling pathway

ABSTRACT

Advanced glycation end products (AGE) are those of the most powerful pathogenic factors that related to diabetic complications. In our study, we investigated the beneficial effects of thymol on AGE induced cell injury and apoptosis in human podocytes (HPCs) and attempted to clarify its mechanisms. Our results revealed that stimulation with AGE could significantly activate RhoA/NF-κB pathway. Results showed thymol could markedly suppress inflammatory responses, cell apoptosis and disordered cytoskeleton. Also thymol restored the expression of podocin, restrained migration capacity. Western blot analysis indicated that it could restore the expression of RhoA, ROCK and vimentin, nephrin, podocin and p65 and IκBα phosphorylation. Moreover, si-RhoA also suppressed the expression of pro-inflammatory cytokines, ROCK, and vimentin and the phosphorylation of p65 and IκBα. In conclusion, thymol inhibits AGE-induced cell injury in HPCs by suppressing the RhoA-NF-κB pathway and may be apromising therapeutic agent.     

Specific monitoring of aflatoxin M1 in real samples using aptamer binding to DNFS based on turn‐on method: A novel biosensor

In the present work, a novel biocompatible scaffold was fabricated for the DNA aptamer immobilization. For the first time, amino‐functionalized dendritic fibrous nanosilica (KCC‐1‐nPr‐NH₂) and gold nanoparticle supported by chitosan (AuNPs‐CS) were synthesized and electrodeposited successfully on the surface of the glassy carbon electrode by chronoamperometry technique. Unique oligonucleotide of aflatoxin M1 (5′‐ATC CGT CAC ACC TGC TCT GAC GCT GGG GTC GAC CCG GAG AAA TGC ATT CCC CTG TGG TGT TGG CTC CCG TAT) labeled by toluidine blue was immobilization on the prepared interface. Hence, a novel aptamer‐based bioassay was formed for highly sensitive quantitation of AFM1 using cyclic voltammetry and differential plus voltammetry. The structure and morphology of GQDs‐CS/KCC‐1‐nPr‐NH₂ were investigated by Fourier‐transform infrared spectroscopy, X‐ray diffraction, atomic force, scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy. The achieved low limit of quantification of apta‐assay for detection of AFM1 was 10fM. Also, calibration curve was linear from 0.1μM to 10fM in real samples. The proposed apta‐assay has acceptable long‐term stability. Designed aptasensor has a lot of remarkable advantages including excellent selectivity, sensitivity, and stability that could be used as facile bio‐device for the determination of AFM1 in milk samples.     

Circulating plasma microRNAs in colorectal neoplasia: A pilot study in assessing response to therapy

IntroductionCurrent serological surveillance markers to monitor colorectal cancer (CRC) or colorectal advanced adenomas (CAA) are hampered by poor sensitivity and specificity. The aim of this study is to identify and validate a panel of plasma microRNAs which change in expression after resection of such lesions.MethodsA prospectively maintained colorectal surgery database was queried for patients in whom both pre- and post-procedural serum samples had been obtained. An initial screening analysis of CRC and CAA patients (5 each) was conducted using screening cards for 380 miRNAs. Four identified miRNAs were combined with a previously described panel of 7 miRNAs that were diagnostically predictive of CRC and CAA. Differential miRNA expression was assessed using quantitative real-time polymerase chain reaction(qRT-PCR).ResultsFifty patients were included (n = 27 CRC, n = 23 CAA). There was no difference in age, gender, or race profile of CRC patients compared to CAA patients. Six miRNA were significantly increased after CRC resection (miR-324, let7b, miR-454, miR-374a, miR-122, miR-19b, all p<0.05), while three miRNAs were significantly increased following CAA resection (miR-454, miR-374a, miR-122, all p<0.05). Three miRNA were increased in common for both (miR-454, miR-374a, miR-122).DiscussionThe expression of miRNAs associated with neoplasia (either CRC or CAA) was significantly increased following surgical resection or endoscopic removal of CRC or CAA. Future studies should focus on the evaluation of these miRNAs in CRC and CAA prognosis.     

Oxidized albumin. The long way of a protein of uncertain function

Background

Proteins are extremely reactive to oxidants and should represent a potential target of instable reactive oxygen. This may represent a problem for plasma proteins since they may be directly modified in vivo in a compartment where antioxidant enzymatic systems are scarcely represented. On the other hand, it is possible that some plasma components have evolved over time to guarantee protection, in which case they can be considered as anti-oxidants.

Scope of review

To present and discuss main studies which addressed the role of albumin in plasma antioxidant activity mainly utilizing in vitro models of oxidation. To present some advances on structural features of oxidized albumin deriving from studies carried out on in vitro models as well as albumin purified in vivo from patients affected by clinical conditions characterized by oxidative stress.

Major conclusions

There are different interaction with HOCl and chloramines. In the former case, HOCl produces an extensive alteration of ²³⁸Trp and ¹⁶²Tyr, ⁴²⁵Tyr, ⁴⁷Tyr, while thiol groups are only partially involved. Chloramines are extremely reactive with the unique free SH group of albumin (³⁴Cys) with the formation of sulfenic and sulfinic acid as intermediates and sulfonic acid as end-product. Oxidized albumin has a modified electrical charge for the addition of an acidic residue and presents α-helix and random coil reorganization with subtle changes in domain orientation.

General significance

Albumin, is the major antioxidants in plasma with a concentration (0.8 mM) higher than other antioxidants by an exponential factor. Functional and protective roles in the presence of oxidative stress must be defined. This article is part of a Special Issue entitled Serum Albumin.