Combining tumour response and progression free survival as surrogate endpoints for overall survival in advanced colorectal cancer.

BACKGROUND: Progression free survival (PFS) and tumour response (TR) have been investigated as surrogate endpoints for overall survival (OS) in advanced colorectal cancer (aCRC), however their validity has been shown to be suboptimal. In recent years, meta-analytic methods allowing for use of multiple surrogate endpoints jointly have been proposed. Our aim was to assess if PFS and TR used jointly as surrogate endpoints to OS improve their predictive value. METHODS: Data were obtained from a systematic review of randomised controlled trials investigating effectiveness of pharmacological therapies in aCRC, including systemic chemotherapies, anti-epidermal growth factor receptor therapies and anti-angiogenic agents. Multivariate meta-analysis was used to model the association patterns between treatment effects on the surrogate endpoints (TR, PFS) and the final outcome (OS). RESULTS: Analysis of 33 trials reporting treatment effects on all three outcomes showed reasonably strong association between treatment effects on PFS and OS, however the association parameters were obtained with a large uncertainty. A weak surrogate relationship was noted between the treatment effects on TR and OS. Modelling the two surrogate endpoints, TR and PFS, jointly as predictors of treatment effect on OS gave no marked improvement to surrogate association patterns. Modest improvement in the precision of the predicted treatment effects on the final outcome was noted in studies investigating anti-angiogenic therapy, however it was likely due to chance. CONCLUSION: The joint use of two surrogate endpoints did not lead to marked improvement in the association between treatment effects on surrogate and final endpoints in advanced colorectal cancer.

Prospective mid-term results of a consecutive series of a short stem.

A large number of short stem prostheses for hip -arthroplasty have been introduced in the past years. Although there is a large increase of publications about short stems, there is still little data available about survival and revision rates. We report prospectively on the outcome of 84 consecutive NANOS® short stem prostheses in 81 patients. We have included 37 female patients and 44 male patients with an average age of 61.6 ±â€ˆ9.2 years. The main diagnoses were osteoarthritis in 67 patients, dysplastic osteoarthritis in 8 patients and avascular necrosis of the femoral head in 6 patients. Along with demographic data and co-morbidities, the Harris Hip Score was recorded preoperatively and at follow-up. The Harris Hip Score increased from 36.6 ±â€ˆ14.5 preoperatively to 94.5 ±â€ˆ8.8 at the final follow-up. During the main follow-up time (27.7 months ±â€ˆ5.7) none of the 84 stems were revised, intraoperatively three fissure fractures occurred.

Osteochondritis dissecans of the medial femoral condyle : New cell-free scaffold as a treatment option.

There is no gold standard in treating osteochondral lesions, which is why the treatment remains very challenging. Osteochondral defects can occur in any joint, but the most common locations are the knee and the ankle. Trauma, repeated microtrauma, avascular necrosis and osteochondritis dissecans (a special type of avascular necrosis) are blamed for the cartilage damage and the damage of adjacent subchondral bone. The self-healing ability of the cartilage is unfortunately very poor; thus, it is necessary to develop new methods of cartilage repair. Unfortunately, few data and long-term survival rates for these new scaffolds are available. We report a case of osteochondritis dissecans treated with a new cell-free scaffold MaioRegen® (Fin-Ceramica Faenza Spa, Faenza, Italy).

[Plastic surgery options for the treatment of chronic foot ulcers]. / Plastische Deckungsmöglichkeiten chronischer Ulzera am Fuß

BACKGROUND: A large number of possibilities to cover chronic ulcers are available. The special aspects of the diabetic foot need to be considered when selecting a flap design for coverage. OBJECTIVES: The purpose of this work is to discuss which plastic surgery techniques are preferred when treating chronic ulcers of the diabetic foot. MATERIALS AND METHODS: Analysis of our own cases and discussion of basic literature. RESULTS: Muscle flaps generally have better perfusion and increased angiogenic activity than skin flaps and, therefore, have better results in the treatment of chronic wounds. Especially important when choosing a procedure for the treatment of the diabetic foot is the situation of vessels and perfusion. CONCLUSIONS: An interdisciplinary approach with internal, orthopedic, and radiological specialists from the beginning of the treatment is the basis for success. The pedicled myocutaneous instep flap with inclusion of the abductor hallucis muscle allows stable coverage in the weight bearing area to be obtained. Free flaps like the anterolateral thigh flap should be raised including a muscle (part of vastus lateralis muscle) to achieve multilayer coverage. Postoperative wound care and training of the flap by the patient are also important for successful treatment and need to be guaranteed in advance.

Diabetes mellitus impairs CD133+ progenitor cell function after myocardial infarction.

BACKGROUND: Circulating progenitor cells (PC) can positively influence the healing of ischaemic myocardium. Cardiovascular risk factors including diabetes mellitus (DM) may have a negative influence on both number and recruitment of PC. Recent evidence suggests that less differentiated CD133(+)PC contribute to myocardial healing and are promising candidates for therapy. Therefore, we investigated whether DM affects CD133(+)PC. METHODS: CD133(+)PC were analyzed in patients following acute myocardial infarction and successful reperfusion [acute myocardial infarction (AMI, n=45) with/without non-insulin-requiring type 2 DM (T2DM)]. Stable coronary artery disease patients (CAD, n = 45) served as stable controls. Number and phenotype of CD133(+)PC were assessed by flow cytometry. CD133(+)PC chemotaxis was assessed towards vascular endothelial growth factor, an angiogenic stimulus upregulated in AMI. The expression of anti-oxidant enzymes in CD133(+)PC was detected by reverse-transcriptase PCR. RESULTS: In non-DM patients, the number of CD133(+)PC increased on day 3 following AMI (P=0.0001). In contrast, no changes were observed in AMI patients with T2DM. Regarding the function of CD133(+)PC, an enhanced chemotactic response was observed following AMI in both non-DM (P=0.0001) and T2DM (P=0.007). However, the AMI-related functional activation was significantly weaker in diabetic patients (P=0.001). Moreover, the expression of catalase was lower in CD133(+)PC from T2DM. CONCLUSIONS: Our results show that T2DM not only limits the abundance of CD133(+)PC following AMI, but also limits their activation. This might be explained by a lower resistance of CD133(+)PC to oxidative stress. Our data provide a possible explanation for the delayed postischaemic vascular healing and myocardial recovery in DM.

Role of strategic cysteine residues in oxidative damage to the yeast plasma membrane H(+)-ATPase caused by Fe- and Cu-containing Fenton reagents.

Damage caused to Saccharomyces cerevisiae SY4 plasma membrane H(+)-ATPase by Fe- and Cu-Fenton reagents was determined in secretory vesicles containing enzyme in which Cys residues were replaced singly or in pairs by Ala. Cys-221 situated in a beta-sheet domain between M2 and M3 segments, phosphorylation domain-located Cys-409 and Cys-532 situated at the ATP-binding site play a role in the inactivation. In the presence of all three residues the enzyme exhibited a certain basic inactivation, which did not change when Cys-532 was replaced with Ala. In mutants having intact Cys-532 but lacking one or both other cysteines, replacement of Cys-221 with Ala led to lower inactivation, suggesting that Cys-221 may serve as a target for metal-catalyzed oxidation and intact Cys-532 promotes this target role of Cys-221. In contrast, the absence of Cys-409 caused higher inactivation by Fe-Fenton. Cys-532 thus seems to serve as a target for Fe-Fenton, intact Cys-409 causing a conformational change that makes Cys-532 less accessible to oxidation. The mutant lacking both Cys-221 and Cys-409 is more sensitive to Fe-Fenton than to Cu-Fenton and the absence of both Cys residues thus seems to expose presumable extra Fe-binding sites. These data and those on protection by ATP, ADP, 1,4-dithiothreitol and deferrioxamine B point to complex interactions between individual parts of the enzyme molecule that determine its sensitivity towards Fenton reagents. ATPase fragmentation caused by the two reagents differed in that the Fe-Fenton reagent produced in Western blot "smears" whereas the Cu-Fenton reagent produced defined fragments.

Mechanisms of Saccharomyces cerevisiae PMA1 H+-ATPase inactivation by Fe2+, H2O2 and Fenton reagents.

Although considerably more oxidation-resistant than other P-type ATPases, the yeast PMA1 H+-ATPase of Saccharomyces cerevisiae SY4 secretory vesicles was inactivated by H2O2, Fe2+, Fe- and Cu-Fenton reagents. Inactivation by Fe2+ required the presence of oxygen and hence involved auto-oxidation of Fe2+ to Fe3+. The highest Fe2- (100 microM) and H2O2 (100 mM) concentrations used produced about the same effect. Inactivation by the Fenton reagent depended more on Fe2+ content than on H2O2 concentration, occurred only when Fe2+ was added to the vesicles first and was only slightly reduced by scavengers (mannitol, Tris, NaN3, DMSO) and by chelators (EDTA, EGTA, DTPA, BPDS, bipyridine, 1,10-phenanthroline). Inactivation by Fe- and Cu-Fenton reagent was the same; the identical inactivation pattern found for both reagents under anaerobic conditions showed that both reagents act via OH*. The lipid peroxidation blocker BHT prevented Fenton-induced rise in lipid peroxidation in both whole cells and in isolated membrane lipids but did not protect the H+-ATPase in secretory vesicles against inactivation. ATP partially protected the enzyme against peroxide and the Fenton reagent in a way resembling the protection it afforded against SH-specific agents. The results indicate that Fe2+ and the Fenton reagent act via metal-catalyzed oxidation at specific metal-binding sites, very probably SH-containing amino acid residues. Deferrioxamine, which prevents the redox cycling of Fe2+, blocked H+-ATPase inactivation by Fe2+ and the Fenton reagent but not that caused by H2O2, which therefore seems to involve a direct non-radical attack. Fe-Fenton reagent caused fragmentation of the H+-ATPase molecule, which, in Western blots, did not give rise to defined fragments bands but merely to smears.

Oxidative stress in microorganisms--I. Microbial vs. higher cells--damage and defenses in relation to cell aging and death.

Oxidative stress in microbial cells shares many similarities with other cell types but it has its specific features which may differ in prokaryotic and eukaryotic cells. We survey here the properties and actions of primary sources of oxidative stress, the role of transition metals in oxidative stress and cell protective machinery of microbial cells, and compare them with analogous features of other cell types. Other features to be compared are the action of Reactive Oxygen Species (ROS) on cell constituents, secondary lipid- or protein-based radicals and other stress products. Repair of oxidative injury by microorganisms and proteolytic removal of irreparable cell constituents are briefly described. Oxidative damage of aerobically growing microbial cells by endogenously formed ROS mostly does not induce changes similar to the aging of multiplying mammalian cells. Rapid growth of bacteria and yeast prevents accumulation of impaired macromolecules which are repaired, diluted or eliminated. During growth some simple fungi, such as yeast or Podospora spp., exhibit aging whose primary cause seems to be fragmentation of the nucleolus or impairment of mitochondrial DNA integrity. Yeast cell aging seems to be accelerated by endogenous oxidative stress. Unlike most growing microbial cells, stationary-phase cells gradually lose their viability because of a continuous oxidative stress, in spite of an increased synthesis of antioxidant enzymes. Unlike in most microorganisms, in plant and animal cells a severe oxidative stress induces a specific programmed death pathway--apoptosis. The scant data on the microbial death mechanisms induced by oxidative stress indicate that in bacteria cell death can result from activation of autolytic enzymes (similarly to the programmed mother-cell death at the end of bacillary sporulation). Yeast and other simple eukaryotes contain components of a proapoptotic pathway which are silent under normal conditions but can be activated by oxidative stress or by manifestation of mammalian death genes, such as bak or bax. Other aspects, such as regulation of oxidative-stress response, role of defense enzymes and their control, acquisition of stress tolerance, stress signaling and its role in stress response, as well as cross-talk between different stress factors, will be the subject of a subsequent review.

Effect of killer toxin K1 on yeast membrane potential reported by the diS-C3(3) probe reflects strain- and physiological state-dependent variations.

The rate and extent of uptake of the fluorescent probe diS-C3(3) reporting on membrane potential in S. cerevisiae is affected by the strain under study, cell-growth phase, starvation and by the concentration of glucose both in the growth medium and in the monitored cell suspension under non-growth conditions. Killer toxin K1 brings about changes in membrane potential. In all types of cells tested, viz. in glucose-supplied stationary or exponential cells of the killer-sensitive strain S6/1 or a conventional strain RXII, or in glucose-free exponential cells of both strains, both active and heat-inactivated toxin slow down the potential-dependent uptake of diS-C3(3) into the cells. This may reflect "clogging" of pores in the cell wall that hinders, but does not prevent, probe passage to the plasma membrane and its equilibration. The clogging effect of heat-inactivated toxin is stronger than that exerted by active toxin. In susceptible cells, i.e. in exponential-phase glucose-supplied cells of the sensitive strain S6/1, this phase of probe uptake retardation is followed by an irreversible red shift in probe fluorescence maximum lambda max indicating damage to membrane integrity and cell permeabilization. A similar fast red shift in lambda max signifying lethal cell damage was found in heat-killed or nystatin-treated cells.

Inactivation of the plasma membrane ATPase of Schizosaccharomyces pombe by hydrogen peroxide and by the Fenton reagent (Fe2+/H2O2): nonradical vs. radical-induced oxidation.

In the absence of added Fe2+, the ATPase activity of isolated Schizosaccharomyces pombe plasma membranes (5-7 mumol P(i) per mg protein per min) is moderately inhibited by H2O2 in a concentration-dependent manner. Sizable inactivation occurs only at 50-80 mmol/L H2O2. The process, probably a direct oxidative action of H2O2 on the enzyme, is not induced by the indigenous membrane-bound iron (19.3 nmol/mg membrane protein), is not affected by the radical scavengers mannitol and Tris, and involves a decrease of both the K(m) of the enzyme for ATP and the V of ATP splitting. On exposing the membranes to the Fenton reagent (50 mumol/L Fe2+ + 20 mmol/L H2O2), which causes a fast production of HO. radicals, the ATPase is 50-60% inactivated and 90% of added Fe2+ is oxidized to Fe3+ within 1 min. The inactivation occurs only when Fe2+ is added before H2O2 and can thus bind to the membranes. The lack of effect of radical scavengers (mannitol, Tris) indicates that HO. radicals produced in the bulk phase play no role in inactivation. Blockage of the inactivation by the iron chelator deferrioxamine implies that the process requires the presence of Fe2+ ions bound to binding sites on the enzyme molecules. Added catalase, which competes with Fe2+ for H2O2, slows down the inactivation but in some cases increases its total extent, probably due to the formation of the superoxide radical that gives rise to delayed HO. production.

Screening women in family practice settings: association between depression and smoking cigarettes.

OBJECTIVE: The purpose of this survey study was to test female family practice outpatients for an association between depression and cigarette smoking. METHODS: The survey consisted of demographic items including questions on smoking, and an eight-item self-report depression screening instrument. Eighty percent of the women (ages 18-91) approached agreed to participate in this study (N = 695). RESULTS: Thirty-two percent scored positive for depression and 28% smoked cigarettes. Cigarette smokers had significantly higher depression scores than did nonsmokers, and heavier smokers (> 10/day) had higher scores than did smokers of 10 or fewer cigarettes/day. CONCLUSION: There appears to be an association between smoking and depression among female family practice patients. This warrants both patient care and research attention.