Systemic treatment approaches in her2-negative advanced breast cancer-guidance on the guidelines

Despite advancements in the treatment of early-stage breast cancer, many patients still develop disease recurrence; others present with de novo metastatic disease. For most patients with advanced breast cancer, the primary treatment intent is noncurative-that is, palliative-in nature. The goals of treatment should therefore focus on maximizing symptom control and extending survival. Treatments should be evaluated on an individualized basis in terms of evidence, but also with full respect for the wishes of the patient in terms of acceptable toxicity. Given the availability of extensive reviews on the roles of endocrine therapy and her2 (human epidermal growth factor receptor 2)-targeted therapies for advanced disease, we focus here mainly on treatment guidelines for the non-endocrine management of her2-negative advanced breast cancer in a Canadian health care context.

Western blot analysis of BK channel β1-subunit expression should be interpreted cautiously when using commercially available antibodies

Large conductance Ca²⁺‐activated K⁺ (BK) channels consist of pore‐forming α‐ and accessory β‐subunits. There are four β‐subunit subtypes (β1–β4), BK β1‐subunit is specific for smooth muscle cells (SMC). Reduced BK β1‐subunit expression is associated with SMC dysfunction in animal models of human disease, because downregulation of BK β1‐subunit reduces channel activity and increases SMC contractility. Several anti‐BK β1‐subunit antibodies are commercially available; however, the specificity of most antibodies has not been tested or confirmed in the tissues from BK β1‐subunit knockout (KO) mice. In this study, we tested the specificity and sensitivity of six commercially available antibodies from five manufacturers. We performed western blot analysis on BK β1‐subunit enriched tissues (mesenteric arteries and colons) and non‐SM tissue (cortex of kidney) from wild‐type (WT) and BK β1‐KO mice. We found that antibodies either detected protein bands of the appropriate molecular weight in tissues from both WT and BK β1‐KO mice or failed to detect protein bands at the appropriate molecular weight in tissues from WT mice, suggesting that these antibodies may lack specificity for the BK β1‐subunit. The absence of BK β1‐subunit mRNA expression in arteries, colons, and kidneys from BK β1‐KO mice was confirmed by RT‐PCR analysis. We conclude that these commercially available antibodies might not be reliable tools for studying BK β1‐subunit expression in murine tissues under the denaturing conditions that we have used. Data obtained using commercially available antibodies should be interpreted cautiously. Our studies underscore the importance of proper negative controls in western blot analyses.

Commercially available anti‐BK β1‐subunit antibodies either detected protein bands of the appropriate molecular weight in tissues from both WT and BK β1‐KO mice or failed to detect protein bands at the appropriate molecular weight in tissues from WT mice. These commercially available antibodies are not reliable tools for studying BK β1‐subunit expression in murine tissues. Data obtained using these antibodies should be interpreted cautiously.

Altered L-type Ca2+ channel activity contributes to exacerbated hypoperfusion and mortality in smooth muscle cell BK channel-deficient septic mice

We determined the contribution of vascular large conductance Ca2+-activated K+ (BK) and L-type Ca2+ channel dysregulation to exaggerated mortality in cecal ligation/puncture (CLP)-induced septic BK channel β1-subunit knockout (BK β1-KO, smooth muscle specific) mice. CLP-induced hemodynamic changes and mortality were assessed over 7 days in wild-type (WT) and BK β1-KO mice that were either untreated, given volume resuscitation (saline), or saline + calcium channel blocker nicardipine. Some mice were euthanized 24 h post-CLP to measure tissue injury and vascular and immune responses. CLP-induced hypotension was similar in untreated WT and BK β1-KO mice, but BK β1-KO mice died sooner. At 24 h post-CLP (mortality latency in BK β1-KO mice), untreated CLP-BK β1-KO mice showed more severe hypothermia, lower tissue perfusion, polymorphonuclear neutrophil infiltration-independent severe intestinal necrosis, and higher serum cytokine levels than CLP-WT mice. Saline resuscitation improved survival in CLP-WT but not CLP-BK β1-KO mice. Saline + nicardipine-treated CLP-BK β1-KO mice exhibited longer survival times, higher tissue perfusion, less intestinal injury, and lower cytokines versus untreated CLP-BK β1-KO mice. These improvements were absent in treated CLP-WT mice, although saline + nicardipine improved blood pressure similarly in both septic mice. At 24 h post-CLP, BK and L-type Ca2+ channel functions in vitro were maintained in mesenteric arteries from WT mice. Mesenteric arteries from BK β1-KO mice had blunted BK/enhanced L-type Ca2+ channel function. We conclude that vascular BK channel deficiency exaggerates mortality in septic BK β1-KO mice by activating L-type Ca2+ channels leading to blood pressure-independent tissue ischemia.

Evolution of drug resistance: insight on TEM β-lactamases structure and activity and β-lactam antibiotics

Since the discovery of the first penicillin bacterial resistance to β-lactam antibiotics has spread and evolved promoting new resistances to pathogens. The most common mechanism of resistance is the production of β-lactamases that have spread thorough nature and evolve to complex phenotypes like CMT type enzymes. New antibiotics have been introduced in clinical practice, and therefore it becomes necessary a concise summary about their molecular targets, specific use and other properties. β-lactamases are still a major medical concern and they have been extensively studied and described in the scientific literature. Several authors agree that Glu166 should be the general base and Ser70 should perform the nucleophilic attack to the carbon of the carbonyl group of the β-lactam ring. Nevertheless there still is controversy on their catalytic mechanism. TEMs evolve at incredible pace presenting more complex phenotypes due to their tolerance to mutations. These mutations lead to an increasing need of novel, stronger and more specific and stable antibiotics. The present review summarizes key structural, molecular and functional aspects of ESBL, IRT and CMT TEM β-lactamases properties and up to date diagrams of the TEM variants with defined phenotype. The activity and structural characteristics of several available TEMs in the NCBI-PDB are presented, as well as the relation of the various mutated residues and their specific properties and some previously proposed catalytic mechanisms.

Does Pro(12)Ala Polymorphism Enhance the Physiological Role of PPARγ2?

Obesity and type 2 diabetes mellitus (T2D) are two major public health problems that have motivated the scientific community to investigate the high contribution of genetic factors to these disorders. The peroxisome proliferator activated by gamma 2 (PPARγ2) plays an important role in the lipid metabolism. Since PPARγ2 is expressed mainly in adipose tissue, a moderate reduction of its activity influences the sensitivity to insulin, diabetes, and other metabolic parameters. The present study aims to contribute to the elucidation of the impact of the Pro(12)Ala polymorphism associated with T2D and obesity through a meta-analysis study of the literature that included approximately 11500 individuals, from which 3870 were obese and 7625 were diabetic. Statistical evidence supports protective effect in T2D of polymorphism Pro(12)Ala of PPARγ2 (OR = 0.702 with 95% CI: 0.622; 0.791, P < 0.01). Conversely the same polymorphism Pro(12)Ala of PPARγ2 seems to favor obesity since 1.196 more chance than nonobese was found (OR = 1.196 with 95% CI: 1.009; 1.417, P < 0.004). Our results suggest that Pro(12)Ala polymorphism enhances both adipogenic and antidiabetogenic physiological role of PPARγ. Does Pro(12)Ala polymorphism represent an evolutionary step towards the stabilization of the molecular function of PPARγ transcription factor signaling pathway?

Spatial modulation microscopy for real-time imaging of plasmonic nanoparticles and cells

Spatial modulation microscopy (SMM) is a technique originally developed for quantitative spectroscopy of individual nano-objects. Here, a parallel implementation of the SMM technique is demonstrated based on a line detector capable of demodulation at kHz frequencies. The capabilities of the imaging system are shown using an array of plasmonic nanoantennas and dendritic cells incubated with gold nanoparticles.

NLRP5 mediates mitochondrial function in mouse oocytes and embryos

Unraveling molecular pathways responsible for regulation of early embryonic development is crucial for our understanding of female infertility. Maternal determinants that control the transition from oocyte to embryo are crucial molecules that govern developmental competence of the newly conceived zygote. We describe a series of defects that are triggered by a disruption of maternal lethal effect gene, Nlrp5. Previous studies have shown that Nlrp5 hypomorph embryos fail to develop beyond the two-cell stage. Despite its importance in preimplantation development, the mechanism by which the embryo arrest occurs remains unclear. We confirmed that Nlrp5 mutant and wild-type females possess comparable ovarian germ pool and follicular recruitment rates. However, ovulated oocytes lacking Nlrp5 have abnormal mitochondrial localization and increased activity in order to sustain physiological ATP content. This results in an accumulation of reactive oxygen species and increased cellular stress causing mitochondrial depletion. Compromised cellular state is also accompanied by increased expression of cell death inducer Bax and depletion of cytochrome c. However, neither genetic deletion (Bax/Nlrp5 double knockout) nor mimetic interference (BH4 domain or Bax inhibitory peptide) were sufficient to alleviate embryo demise caused by depletion of Nlrp5. We therefore conclude that lack of Nlrp5 in oocytes triggers premature activation of the mitochondrial pool, causing mitochondrial damage that cannot be rescued by inactivation of Bax.

Protective effects of the dipeptidyl peptidase IV inhibitor sitagliptin in the blood-retinal barrier in a type 2 diabetes animal model

AIM

The aim of this study was to evaluate the efficacy of sitagliptin, a dipeptidyl peptidase IV inhibitor (DPP-IV), in preventing the deleterious effects of diabetes on the blood-retinal barrier in male Zucker Diabetic Fatty (ZDF) rats.

METHODS

ZDF rats at 20 weeks of age were treated with sitagliptin (10 mg/kg/day) during 6 weeks. The effect of the drug on glycaemia was assessed by evaluating glycated haemoglobin (HbA1c). The content and/or distribution of tight junction (TJ) proteins occludin and claudin-5, as well as nitrotyrosine residues, interleukin (IL)-1β, BAX and Bcl-2 was evaluated in the retinas by western blotting and/or immunohistochemistry. Retinal cell apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) assay. The number of CD34+ cells present in peripheral circulation was assessed by flow cytometry, and endothelial progenitor cells (EPC) adhesion ability to the retinal vessels was evaluated by immunohistochemistry.

RESULTS

Sitagliptin improved glycaemic control as reflected by a significant decrease in HbA1c levels by about 1.2%. Treatment with sitagliptin prevented the changes in the endothelial subcellular distribution of the TJ proteins induced by diabetes. Sitagliptin also decreased the nitrosative stress, the inflammatory state and cell death by apoptosis in diabetic retinas. Diabetic animals presented decreased levels of CD34+ cells in the peripheral circulation and decreased adhesion ability of EPC to the retinal vessels. Sitagliptin allowed a recovery of the number of CD34+ cells present in the bloodstream to levels similar to their number in controls and increased the adhesion ability of EPC to the retinal vessels.

CONCLUSIONS

Sitagliptin prevented nitrosative stress, inflammation and apoptosis in retinal cells and exerted beneficial effects on the blood-retinal barrier integrity in ZDF rat retinas.

EVAR for aortoiliac aneurysms, including iliac branched grafts

For aortoiliac aneurysms involving the common iliac arteries several treatment options have been developed. In the early stages of the endovascular era the internal iliac artery was usually overstented with or without embolization. Thereafter relocation or bypass techniques were used in an attempt to preserve the internal iliac artery. Then endovascular techniques were used that involved the need for a femoro-femoral cross-over bypass. The development of iliac branched devices made it possible to preserve the internal iliac artery by endovascular means only. A first version of the iliac bifurcated graft needed to be pulled into the internal iliac artery but this technique proved too difficult. Newer versions including straight side-branches or helical side-branches for the internal iliac artery require a cross-over catheterization and introduction of a stent-graft to bridge the gap between the internal iliac artery and the iliac branch. Anatomical criteria including sufficient length of the common iliac artery and a normal calibre internal iliac artery should be taken into account, but also the health status of the patient, before one decides to use an iliac branched device for a patient with an aortoiliac aneurysm. Additional costs and technical challenges need to be balanced with the potential benefits for active patients who would be at risk for buttock claudication.

Automated microinjection of recombinant BCL-X into mouse zygotes enhances embryo development

Progression of fertilized mammalian oocytes through cleavage, blastocyst formation and implantation depends on successful implementation of the developmental program, which becomes established during oogenesis. The identification of ooplasmic factors, which are responsible for successful embryo development, is thus crucial in designing possible molecular therapies for infertility intervention. However, systematic evaluation of molecular targets has been hampered by the lack of techniques for efficient delivery of molecules into embryos. We have developed an automated robotic microinjection system for delivering cell impermeable compounds into preimplantation embryos with a high post-injection survival rate. In this paper, we report the performance of the system on microinjection of mouse embryos. Furthermore, using this system we provide the first evidence that recombinant BCL-XL (recBCL-XL) protein is effective in preventing early embryo arrest imposed by suboptimal culture environment. We demonstrate that microinjection of recBCL-XL protein into early-stage embryos repairs mitochondrial bioenergetics, prevents reactive oxygen species (ROS) accumulation, and enhances preimplantation embryo development. This approach may lead to a possible treatment option for patients with repeated in vitro fertilization (IVF) failure due to poor embryo quality.

Metastatic disease causing unilateral isolated hypoglossal nerve palsy

The authors present the case of a middle-aged woman diagnosed with lobar carcinoma in situ in her right breast. She eventually underwent a mastectomy and reconstruction. Histology revealed grade II invasive ductal carcinoma and she was commenced on adjuvant letrozole. The following year a MRI scan revealed she had developed spinal metastases and CT confirmed the presence of liver and lung metastases. She presented with a 5-month history of tongue weakness and difficulty manipulating food to the back of her mouth. On examination, there was marked right-sided hemiatrophy of the tongue with deviation of the tongue to the right side upon protrusion. MRI demonstrated ill-defined enhancing material close to the intracranial opening of the right hypoglossal canal. The patient was referred for consideration of radiotherapy. Due to the comorbidities of the patient, she was not a candidate for neurosurgical intervention.

In situ mechanical characterization of mouse oocytes using a cell holding device

This paper presents a cellular force measurement technique that allows for mechanical characterization of mouse oocytes during microinjection (i.e., in situ) without requiring a separate characterization process. The technique employs an elastic cell holding device and a sub-pixel computer vision tracking algorithm to resolve cellular forces in real time with a nanonewton force measurement resolution (2 nN at 30 Hz). Mechanical properties (i.e., stiffness) of both healthy and defective mouse oocytes are characterized. The experimental results suggest that the in situ obtained force-deformation data are useful for distinguishing healthy mouse oocytes from those with aging-induced cellular defects, promising an approach for oocyte quality assessment during microinjection. Biomembrane and cytoskeleton structures of the healthy and defective oocytes are also investigated in an attempt to correlate the measured subtle mechanical difference to cellular structure changes.

Methylglyoxal-induced imbalance in the ratio of vascular endothelial growth factor to angiopoietin 2 secreted by retinal pigment epithelial cells leads to endothelial dysfunction

Progressive microvascular complications are a main feature of diabetes and are associated with impairment of the angiogenic response. Methylglyoxal (MGO) has been implicated in the molecular events that lead to endothelial dysfunction in diabetes. In this study, we hypothesize that increased levels of MGO disrupt the ratio of vascular endothelial growth factor (VEGF) to angiopoietin 2 (Ang 2) secreted by retinal pigment epithelial (RPE) cells, which provides a key destabilizing signal that leads to apoptosis and decreased proliferation of retinal endothelial cells. Indeed, we show that MGO increases the levels of Ang 2 and dramatically decreases the levels of VEGF secreted by RPE cells in response to hypoxia. Downregulation of VEGF is likely to be related to decreased hypoxia-inducible factor-1alpha (HIF-1alpha) protein levels and HIF-1 transcriptional activity. Data further show that MGO-induced imbalance in the VEGF/Ang II ratio significantly changes the levels of BAX and Bcl-2 in endothelial cells. Moreover, this imbalance is accompanied by an increase in the activity of caspase-3 and decreased proliferation of endothelial cells. Data obtained in cell culture systems are consistent with observations in retinas of diabetic animals, where increased availability of MGO is associated with changes in distribution and levels of HIF-1alpha, VEGF and Ang 2 and increased microvascular permeability. In conclusion, the MGO-induced imbalance in the VEGF/Ang 2 ratio secreted by retinal epithelial cells activates apoptosis and decreases proliferation of retinal endothelial cells, which are likely to contribute to endothelial dysfunction in diabetic retinopathy.