407 research outputs found
Symbiont diversity is not involved in depth acclimation in the Mediterranean sea whip Eunicella singularis
In symbiotic cnidarians, acclimation to depth and lower irradiance can involve physiological changes in the photosynthetic dinoflagellate endosymbiont, such as increased chlorophyll content, or qualitative modifications in the symbiont population in favour of better adapted strains. It has been argued that a lack of capacity to acquire new symbionts could limit the bathymetric distribution of the host species, or compromise its long-term survival in a changing environment. But is that always true? To address this question, we investigated the symbiont genetic diversity in Eunicella singularis, a Mediterranean sea whip species with a wide bathymetric distribution (10 to 50 m depth), which has recently suffered from mass mortalities after periods of abnormally high sea temperatures. We measured symbiont population densities and chlorophyll content in natural populations, and followed the response of the holobionts after reciprocal transplantations to deep and shallow depths. A total of 161 colonies were sampled at 2 depths (10 and 30 m) at 5 sites in the northwestern Mediterranean. All colonies harboured a single ribosomal Symbiodinium clade (A'), but a relatively high within-clade genetic diversity was found among and within colonies. This diversity was not structured by depth, even though the deeper colonies contained significantly lower population densities of symbionts and less chlorophyll. We did, however, reveal host-symbiont specificity among E. singularis and other Mediterranean cnidarian species. Transplantation experiments revealed a limit of plasticity for symbiont population density and chlorophyll content, which in turn questions the importance of the trophic role of Symbiodinium in E. singularis
Medical ovariectomy in menopausal breast cancer patients with high testosterone levels : a further step toward tailored therapy
Five years of adjuvant therapy with anti-estrogens reduce the incidence of disease progression by about 50% in estrogen receptor-positive breast cancer patients, but late relapse can still occur after anti-estrogens have been discontinued. In these patients, excessive androgen production may account for renewed excessive estrogen formation and increased risks of late relapse. In the 50% of patients who do not benefit with anti-estrogens, the effect of therapy is limited by de novo or acquired resistance to treatment. Androgen receptor and epidermal growth factor receptor overexpression are recognized mechanisms of endocrine resistance suggesting the involvement of androgens as activators of the androgen receptor pathway and as stimulators of epidermal growth factor synthesis and function. Data from a series of prospective studies on operable breast cancer patients, showing high serum testosterone levels are associated to increased risk of recurrence, provide further support to a role for androgens in breast cancer progression. According to the above reported evidence, we proposed to counteract excessive androgen production in the adjuvant setting of estrogen receptor-positive patients and suggested selecting postmenopausal patients with elevated levels of serum testosterone, marker of ovarian hyperandrogenemia, for adjuvant treatment with a gonadotropins-releasing hormone analogue (medical oophorectomy) in addition to standard therapy with anti-estrogens. The proposed approach provides an attempt of personalized medicine that needs to be further investigated in clinical trials
Metabolic syndrome and postmenopausal breast cancer in the ORDET cohort : a nested case-control study
Background and aims: The increase in breast cancer incidence over recent decades has been accompanied by an increase in the frequency of metabolic syndrome. Several studies suggest that breast cancer risk is associated with the components of metabolic syndrome (high serum glucose and triglycerides, low HDL-cholesterol, high blood pressure, and abdominal obesity), but no prospective study has investigated risk in relation to the presence of explicitly defined metabolic syndrome. We investigated associations between metabolic syndrome, its components, and breast cancer risk in a nested case-control study on postmenopausal women of the ORDET cohort. Methods and results: After a median follow-up of 13.5 years, 163 women developed breast cancer; metabolic syndrome was present in 29.8%. Four matched controls per case were selected by incidence density sampling, and rate ratios were estimated by conditional logistic regression. Metabolic syndrome (i.e. presence of three or more metabolic syndrome components) was significantly associated with breast cancer risk (rate ratio 1.58 [95% confidence interval 1.07-2.33]), with a significant risk increase for increasing number of components (P for trend 0.004). Among individual metabolic syndrome components, only low serum HDL-cholesterol and high triglycerides were significantly associated with increased risk. Conclusions: This prospective study indicates that metabolic syndrome is an important risk factor for breast cancer in postmenopausal women. Although serum HDL-cholesterol and triglycerides had the strongest association with breast cancer, all components may contribute to increased risk by multiple interacting mechanisms. Prevention or reversal of metabolic syndrome by life-style changes may be effective in preventing breast cancer in postmenopausal women
MicroRNAs and cancer metabolism reprogramming : the paradigm of metformin
Increasing evidence witnesses that cancer metabolism alterations represent a critical hallmark for many types of human tumors. There is a strong need to understand and dissect the molecular mechanisms underlying cancer metabolism to envisage specific biomarkers and underpin critical molecular components that might represent novel therapeutic targets. One challenge, that is the focus of this review, is the reprogramming of the altered metabolism of a cancer cell toward that of un-transformed cell. The anti-hyperglicemic agent, metformin has proven to be effective in reprogramming the metabolism of cancer cells even from those subpopulations endowed with cancer stem like features and very high chemoresistenace to conventional anticancer treatments. A functional interplay involving selective modulation of microRNAs (miRNAs) takes place along the anticancer metabolic effects exerted by metformin. The implications of this interplay will be also discussed in this review
Graphene oxide integrated sensor for electrochemical monitoring ofmitomycin C–DNA interaction
WOS: 000302308600025PubMed ID: 22439135We present a graphene oxide (GO) integrated disposable electrochemical sensor for the enhanced detection of nucleic acids and the sensitive monitoring of the surface-confined interactions between the anticancer drug mitomycin C (MC) and DNA. Interfacial interactions between immobilized calf thymus double-stranded (dsDNA) and anticancer drug MC were investigated using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques. Based on three repetitive voltammetric measurements of 120 mu g mL(-1) DNA immobilized on GO-modified electrodes, the RSD % (n = 3) was calculated as 10.47% and the detection limit (DL) for dsDNA was found to be 9.06 mu g mL(-1). EIS studies revealed that the binding of the drug MC to dsDNA leads to a gradual decrease of its negative charge. As a consequence of this interaction, the negative redox species were allowed to approach the electrode, and thus increase the charge transfer kinetics. On the other hand, DPV studies exploited the decrease of the guanine signal due to drug binding as the basis for specifically probing the biointeraction process between MC and dsDNA.Royal Society through Joint Project Scheme [1212R0168]; Turkish Academy of Sciences (TUBA)Turkish Academy of SciencesThis work was supported by the Royal Society through Joint Project Scheme (Project No. 1212R0168). A.E. acknowledges the Turkish Academy of Sciences (TUBA) as an Associate member for its partial support. Authors would like to thank Dr. M. McMullan for the assistance on the synthesis of graphene oxide
A novel approach to breast cancer prevention: reducing excessive ovarian androgen production in elderly women
Minimizing endogenous estrogen production and activity in women at high risk for breast cancer is a prominent approach to prevention of the disease. A number of clinical trials have shown that the administration of selective-estrogen receptor modulators or aromatase inhibitors significantly reduces the incidence of breast cancer in healthy women. Unfortunately, these drugs often produce adverse effects on the quality of life and are, therefore, poorly accepted by many women, even those who are at high risk for breast cancer. We propose a novel alternative approach to decreasing estrogen production: suppression of ovarian synthesis of the androgen precursors of estrogens by administration of long-acting gonadotropin-releasing hormone analogs to women with ovarian stromal hyperplasia. The specific target population would be elderly postmenopausal women, at increased risk of breast cancer, and with high blood levels of testosterone, marker of ovarian hyperandrogenemia, and recognized factor of risk for breast cancer. Testosterone levels are measured at baseline to identify women at risk and during the follow-up to evaluate the effectiveness of therapy. The postmenopausal ovary is an important source of excessive androgen production which originates from the ovarian interstitial cell hyperplasia frequently present in breast cancer patients. We propose to counter the source of androgen excess in women with ovarian stromal hyperplasia, thus reducing the substrate for estrogen formation without completely inhibiting estrogen synthesis. Available evidence indicates that gonadotropin-releasing hormone analogs can be safely used for breast cancer prevention in postmenopausal women
Anticoagulation for the long-term treatment of venous thromboembolism in patients with cancer
Background: Cancer increases the risk of thromboembolic events in patients including those receiving anticoagulation treatments. Objectives: To compare the efficacy and safety of low molecular weight heparin (LMWH) and oral anticoagulants for the long-term treatment of venous thromboembolism (VTE) in patients with cancer. Search methods: We conducted a comprehensive search for studies of anticoagulation in cancer patients including 1. a February 2013 electronic search of: the Cochrane Central Register of Controlled Trials (CENTRAL Issue 12, 2012), MEDLINE, and EMBASE; 2. a handsearch of conference proceedings; 3. checking of references of included studies; 4. use of the 'related citation' feature in PubMed; and 5. a search of clinicaltrials.gov for ongoing studies. Selection criteria: We included randomized controlled trials (RCTs) comparing long-term treatment with LMWH versus oral anticoagulants (vitamin K antagonist (VKA) or ximelagatran) in patients with cancer and symptomatic objectively confirmed VTE. Data collection and analysis: Using a standardized data form, we extracted data on methodological quality, participants, interventions and outcomes of interest: survival, recurrent VTE, major bleeding, minor bleeding, thrombocytopenia, and postphlebitic syndrome. We assessed the quality of evidence at the outcome level following the GRADE approach. Main results: Of 9559 identified citations, 10 RCTs (11 reports) were eligible and reported data for 1981 patients with cancer. We excluded 14 studies in which patients with cancer constituted study subgroups, but did not report outcome data for them. Meta-analysis of seven RCTs comparing LMWH with VKA found no statistically significant survival benefit (hazard ratio (HR) 0.96; 95% confidence interval (CI) 0.81 to 1.14) but a statistically significant reduction in VTE (HR 0.47; 95% CI 0.32 to 0.71). The remaining findings did not exclude a beneficial or harmful effect of LMWH compared with VKA for the outcomes of major bleeding (RR 1.07; 95% CI 0.52 to 2.19), minor bleeding (RR 0.89; 95% CI 0.51 to 1.55), or thrombocytopenia (RR 0.98; 95% CI 0.57 to 1.66). We judged the quality of evidence as low for mortality, major bleeding, and minor bleeding, and as moderate for recurrent VTE. One RCT comparing dabigatran with VKA did not exclude beneficial or harmful effects of one agent over the other. One RCT comparing six months' extension of anticoagulation with 18 months of ximelagatran 24 \u3bcg twice daily versus no extended ximelagatran did not exclude beneficial or harmful effects for the outcomes of reduction in VTE, mortality, and minor bleeding. One RCT comparing once-weekly subcutaneous injection of idraparinux for three or six months versus standard treatment (parenteral anticoagulation followed by warfarin or acenocoumarol) suggested a reduction in recurrent VTE (HR 0.39; 95% CI 0.14 to 1.11) at six months, but did not exclude beneficial or harmful effects for the outcomes of mortality (HR 0.99; 95% CI 0.66 to 1.48) and major bleeding (RR 1.04; 95% CI 0.39 to 2.83). Authors' conclusions: For the long-term treatment of VTE in patients with cancer, LMWH compared with VKA reduces venous thromboembolic events but not mortality. The decision for a patient with cancer and VTE to start long-term LMWH versus oral anticoagulation should balance the benefits and harms and integrate the patient's values and preferences for the important outcomes and alternative management strategies
Metformin : on ongoing journey across diabetes, cancer therapy and prevention
Cancer metabolism is the focus of intense research, which witnesses its key role in human tumors. Diabetic patients treated with metformin exhibit a reduced incidence of cancer and cancer-related mortality. This highlights the possibility that the tackling of metabolic alterations might also hold promising value for treating cancer patients. Here, we review the emerging role of metformin as a paradigmatic example of an old drug used worldwide to treat patients with type II diabetes which to date is gaining strong in vitro and in vivo anticancer activities to be included in clinical trials. Metformin is also becoming the focus of intense basic and clinical research on chemoprevention, thus suggesting that metabolic alteration is an early lesion along cancer transformation. Metabolic reprogramming might be a very efficient prevention strategy with a profound impact on public health worldwide
In vivo and in vitro evidence that intrinsic upper- and lower-limb skeletal muscle function is unaffected by ageing and disuse in oldest-old humans
Aim: To parse out the impact of advanced ageing and disuse on skeletal
muscle function, we utilized both in vivo and in vitro techniques to comprehensively
assess upper- and lower-limb muscle contractile properties in
8 young (YG; 25 6 years) and 8 oldest-old mobile (OM; 87 5 years)
and 8 immobile (OI; 88 4 years) women.
Methods: In vivo, maximal voluntary contraction (MVC), electrically
evoked resting twitch force (RT), and physiological cross-sectional area
(PCSA) of the quadriceps and elbow flexors were assessed. Muscle biopsies
of the vastus lateralis and biceps brachii facilitated the in vitro assessment
of single fibre-specific tension (Po).
Results: In vivo, compared to the young, both the OM and OI exhibited
a more pronounced loss of MVC in the lower limb [OM (60%) and OI
(75%)] than the upper limb (OM = 51%; OI = 47%). Taking into
account the reduction in muscle PCSA (OM = 10%; OI = 18%), only
evident in the lower limb, by calculating voluntary muscle-specific force,
the lower limb of the OI (40%) was more compromised than the OM
(13%). However, in vivo, RT in both upper and lower limbs (approx.
9.8 N m cm
2) and Po (approx. 123 mN mm
2), assessed in vitro, implies
preserved intrinsic contractile function in all muscles of the oldest-old and
were well correlated (r = 0.81).
Conclusion: These findings suggest that in the oldest-old, neither
advanced ageing nor disuse, per se, impacts intrinsic skeletal muscle function,
as assessed in vitro. However, in vivo, muscle function is attenuated
by age and exacerbated by disuse, implicating factors other than skeletal
muscle, such as neuromuscular control, in this diminution of function.
Keywords in vitro, in vivo, oldest-old, sarcopeni
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