Real-world effectiveness of ixazomib combined with lenalidomide and dexamethasone in relapsed/refractory multiple myeloma: the REMIX study

Ixazomib (IXA) is an oral proteasome inhibitor (PI) used in combination with lenalidomide and dexamethasone (IXA-Rd) for patients with relapsed and/or refractory multiple myeloma (RRMM). The REMIX study is one of the largest prospective, real-world analysis of the effectiveness of IXA-Rd in the setting of RRMM. Conducted in France between August 2017 and October 2019, the REMIX study, a non-interventional prospective study, included 376 patients receiving IXA-Rd in second line or later and followed for at least 24 months. Primary endpoint was the median progression-free survival (mPFS). Median age was 71 years (Q1-Q3 65.0 - 77.5) with 18.4% of participants older than 80 years. IXA-Rd was initiated in L2, L3 and L4 + for 60.4%, 18.1% and 21.5%, respectively. mPFS was 19.1 months (95% CI [15.9, 21.5]) and overall response rate (ORR) was 73.1%. mPFS was 21.5, 21.9 and 5.8 months in patients receiving IXA-Rd as L2, L3, L4 + respectively. Among patients receiving IXA-Rd in L2 and L3, mPFS was similar for patients previously exposed to lenalidomide (19.5 months) than for those lenalidomide naive (not exposed, 22.6 months, p = 0.29). mPFS was 19.1 months in patients younger than 80 years and 17.4 months in those 80 years or older (p = 0.06) with similar ORR (72.4% and 76.8%) in both subgroups. Adverse events (AEs) were reported in 78.2% of patients including 40.7% of treatment-related AE. IXA discontinuation was due to toxicity in 21% of patients. To conclude, the results of the REMIX study are consistent with the results of Tourmaline-MM1 and confirm the benefit of IXA-Rd combination in real life. It shows the interest of IXA-Rd in an older and frailer population, with an acceptable effectiveness and tolerance.

Hexagonal silicon-germanium nanowire branches with tunable composition

Hexagonal SiGe-2H has been recently shown to have a direct bandgap, and holds the promise to be compatible with silicon technology. Hexagonal Si and Ge have been grown on an epitaxial lattice matched template consisting of wurtzite GaP and GaAs, respectively. Here, we present the growth of hexagonal Si and SiGe nanowire branches grown from a wurtzite stem by the vapor-liquid-solid growth mode, which is substantiated byin situtransmission electron microscopy. We show that the composition can be tuned through the whole range of stoichiometry from Si to Ge, and the possibility to realize Si and SiGe heterostructures in these branches.

Atrioventricular nodal ablation with pacemaker implant is associated with improved safety outcomes compared to pulmonary vein isolation of atrial fibrillation with heart failure

Background

Pulmonary vein isolation (PVI) and atrioventricular nodal ablation (AVNA) with pacemaker implant have both been advocated for patients with atrial fibrillation (AF) and heart failure with reduced ejection fraction (HFrEF). Direct comparisons between the two are limited.

Purpose

We sought to compare outcomes and complications following PVI versus AVNA with implant of a cardiac implantable electronic device (CIED) among patients with AF and HFrEF.

Methods

We queried the National Inpatient Sample from 2011 to 2019, using relevant ICD-9 and -10 diagnostic and procedural codes for AF, HFrEF, ablation, and CIED implant to identify our study cohort. Exclusion criteria included presence of a pre-existing CIED, ventricular arrhythmias, non-AF supraventricular arrhythmias, and surgical AF ablation. Baseline characteristics included age, sex, race, and comorbidities related to AF and cardiovascular disease. Severity of comorbidities was assessed via Deyo-Charlson Comorbidity Index (Deyo-CCI). Outcomes investigated include all-cause mortality, major adverse cardiovascular events (MACE), extra-cardiac procedural complications, length of stay, and total hospital charges. Outcomes associations were analyzed using multivariate logistic regression adjusted for baseline characteristics that were significantly different (P<0.05) between cohorts expressed as adjusted odds ratios (aOR) and 95% confidence intervals (CI). SPSS v28.0 (IBM, Armonk, NY) was used to carry out all calculations.

Results

We identified 3,565 encounters for PVI and 1,355 for AVNA with CIED implant among hospitalized patients with AF and HFrEF. Patients who underwent AVNA were more often older (73.8 vs 66.2 years), with more severe comorbidities (mean Deyo-CCI score 2.9 vs 2.6) and were more likely to have an emergent procedure performed (81.3% vs 69.7%; p<0.001 for all). However, the AVNA cohort had less mortality (0.5% vs 1.2%, p=0.03), MACE (6.1% vs 7.8%, p=0.04), and total complications (12.7% vs 16.3%, p=0.002), but longer hospital stay (8.0 vs 6.5 days) and higher total charges ($201,100 vs $159,382; p<0.001 for both). After adjusting for confounders, AVNA remained independently associated with decreased odds of mortality (aOR: 0.370; 95% CI [0.159–0.862], p=0.02), MACE (aOR: 0.552; 95% CI [0.420–0.726], p<0.001), and total complications (aOR: 0.708; 95% CI [0.589–0.852], p<0.001).

Conclusion

Despite older age with more severe comorbidities and less elective procedures, hospitalized patients with AF and HFrEF who underwent AVNA with CIED implant had improved safety outcomes compared to PVI. Further studies comparing the intermediate and long-term outcomes and efficacy between therapies are needed to better delineate which would best serve this population.

Funding Acknowledgement

Type of funding sources: None.

Assessing outcomes following catheter ablation of ventricular tachycardia in patients with durable left ventricular assist devices

Background

Management of ventricular tachycardia (VT) after implant of a durable left ventricular assist device (LVAD) is challenging, without consensus on optimal therapy. Multiple small studies have examined catheter ablation of VT in these patients with low reported incidence of complications.

Purpose

We sought to evaluate periprocedural outcomes following VT ablation among LVAD recipients.

Methods

We queried the National Inpatient Sample from 2011 to 2019 to conduct our study. Baseline characteristics include age, sex, race, and comorbidities related to cardiovascular disease. Comorbidity severity was assessed using the Deyo-Charlson Comorbidity Index (Deyo-CCI). Patients with any supraventricular arrhythmias were excluded. Outcomes investigated include heart transplant procedure, all-cause mortality, major adverse cardiovascular events (MACE), and periprocedural complications. Multivariate regression was used to analyze outcomes associations adjusted for baseline characteristics that were significantly different (P<0.05) between cohorts expressed as adjusted odds ratios (aOR) and 95% confidence intervals (CI). SPSS v28.0 (IBM, Armonk, NY) was used to carry out all calculations.

Results

We identified 56 patients who underwent ablation among 2,202 LVAD recipients hospitalized for VT. Patients who underwent ablation were more likely to have ischemic cardiomyopathy (33.9% vs. 22.2%, p=0.03) or an automated implantable cardioverter-defibrillator (55.4% vs 34.3%, p=0.001). There were otherwise no significant differences between cohorts (mean Deyo-CCI score of 2.3 for both, p=0.48). Between those who did and did not undergo ablation, there were no significant differences in heart transplant (5.4 vs 5.0%, p=0.9), mortality (7.1% vs 7.0%, p=0.96), total strokes (3.6% vs 5.0%, p=0.48), myocardial infarction (3.6% vs 4.6%, p=0.71), overall MACE (8.9% vs 10.2%, p=0.26) or total complications (35.7% vs 41.9%, p=0.35). There were no incidents of pump thrombosis in the ablation group, but 92 events (4.3%) were found in the medical therapy group. Multivariate analysis affirmed no significant association between ablation and mortality (aOR 1.277, CI [0.450–3.629]), MACE (aOR 1.125, CI [0.436–2.902]), or total complications (aOR 0.932, CI [0.528–1.645]).

Conclusion

Overall complications following VT ablation among LVAD patients were higher than previously reported but no statistically significant differences were found compared to conservative management. While ablation appears safe to perform, particularly among those with structural heart disease and ischemic cardiomyopathy, longer duration studies are needed to determine the efficacy of this procedure.

Funding Acknowledgement

Type of funding sources: None.

Gender disparities in ventricular tachycardia: evaluating clinical outcomes and interventions

Background

Gender differences in the etiology of ventricular arrhythmia are well-known and can potentially affect clinical outcomes. Women have been under-represented in studies investigating ventricular tachycardia (VT). Thus, gender differences in clinical outcomes of VT are poorly defined.

Purpose

We sought to elucidate the clinical outcomes and interventions among women with VT.

Methods

We used the National Inpatient Sample to identify patients aged 18 and older admitted with VT from 2011 to 2019. Observations missing data on age, sex and mortality were excluded. Baseline characteristics include age, race, and comorbidities related to cardiovascular disease. Severity of comorbidities was assessed via the Deyo-Charlson Comorbidity Index (Deyo-CCI) score. Outcomes investigated include all-cause mortality, major adverse cardiovascular events (MACE), and incidence of catheter ablation, cardioversion, and automated implantable cardioverter defibrillator (AICD) insertion. Gender and outcomes association were analyzed using multivariable logistic regression adjusted for baseline characteristics that were significantly different (P<0.05) between cohorts expressed as adjusted odds ratios (aOR) and 95% confidence intervals (CI). SPSS v28.0 (IBM, Armonk, NY) was used to carry out all calculations.

Results

Between 2011 and 2019, there were an estimated 3,544,445 hospital admissions for VT, of which, 33.8% were women, who were more likely to be older (69.2 vs 68.0 years) and of minority descent (30.3% vs 26.7%) compared to men. Women were less likely to have coronary artery disease (43.5% vs 62.2%) or ischemic cardiomyopathy (5.0% vs 11.9%) and had a lower mean Deyo-CCI score (2.2 vs 2.4; p<0.001 for all). Women had a higher incidence of mortality (10.6% vs 9.2%) and ischemic stroke (5.3% vs 4.5%), but less acute coronary syndrome (17.6% vs 21.4%; p<0.001 for all). Overall incidence of MACE was lower among women (28.6% vs 31.4%; p<0.001). Multivariate regression analysis demonstrated that female sex remained independently associated with increased odds for all-cause mortality (aOR: 1.089; 95% CI: [1.062–1.116], p<0.001) although decreased odds for MACE (aOR: 0.952; 95% CI: [0.939–0.965]). Female sex was also independently associated with decreased odds for cardioversion (aOR: 0.936; 95% CI: [0.910–0.963]), AICD insertion, (aOR: 0.737; 95% CI: [0.711–0.764]) and ablation (aOR: 0.806; 95% CI: [0.766–0.847]; all p<0.001).

Conclusion

In this retrospective analysis of patients hospitalized with VT, women had less coronary artery disease and less MACE, yet all-cause mortality was higher. Female sex was also independently associated with fewer interventions, including AICD insertion and ablation. Although there are gender differences in risk factors and causes of VT, this does not fully explain disparities in care and outcomes. Further studies are needed to explore and elucidate these gender disparities.

Funding Acknowledgement

Type of funding sources: None.

Cardiac tamponade in venoarterial extracorporeal membrane oxygenation

Cardiac tamponade is a challenging diagnosis in the unstable patient requiring extracorporeal membrane oxygenation. We present a case of cardiac tamponade secondary to hemorrhagic pericardial effusion that developed in the setting of cardiopulmonary resuscitation and venoarterial extracorporeal membrane oxygenation. Specifically, we aim to discuss the pertinent diagnostic challenges in confirming this diagnosis.

Prognostic factors of overall survival for patients with FIGO stage IIIc or IVa ovarian cancer treated with neo-adjuvant chemotherapy followed by interval debulking surgery: A multicenter cohort analysis from the FRANCOGYN study group

INTRODUCTION

The aim of this study was to identify prognostic factors of overall survival in patients with FIGO stage IIIc or IVa ovarian cancer (OC) treated by neo-adjuvant chemotherapy (NAC) followed by interval debulking surgery.

MATERIALS AND METHODS

Data from 483 patients with ovarian cancer were retrospectively collected, from January 1, 2000 to December 31, 2016, from the FRANCOGYN database, regrouping data from 11 centers specialized in ovarian cancer treatment. Median overall survival was determined using the Kaplan-Meier method. Univariate and multivariate analysis were performed to define prognostic factors of overall survival.

RESULTS

The median overall survival was 52 after a median follow up of 30 months. After univariate analysis, factors significantly associated with decreased overall survival were; no pelvic and/or para-aortic lymphadenectomy (p = 0.002), residual disease (CC1/CC2/CC3) after surgery (p < 0.001), positive cytology after NAC (p < 0.001), omental disease after NAC (p = 0.002), no pathologic complete response (pCR) (p = 0.002). In multivariate analysis, factors significantly associated with decreased overall survival were; residual disease after surgery (HR = 1.93; CI95% (1.16-3.21), p = 0.01) and positive cytology after NAC (HR = 1.59; CI95% (1.01-2.55), p = 0.05). Patients with no residual disease after surgery had a median overall survival of 64 months versus 35 months for patients with residual disease. Patients with negative cytology after NAC had a median overall survival of 71 months versus 43 months for patients with positive cytology after NAC.

CONCLUSION

In this first and largest French based retrospective study, complete cytoreductive surgery in ovarian cancer remains the main prognostic factor of overall survival.

[Comparing prediction performances of 18F-FDG PET and CGFL/Curie nomogram to predict pathologic complete response after neoadjuvant chemotherapy for HER2-positive breast cancers]

OBJECTIVES

The aim of this study was to compare the value of ¹⁸F-fluorodesoxyglucose positron emission tomography (¹⁸F-FDG PET/CT) with CGFL/Curie nomogram to predict a pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) in women with human epidermal growth factor 2 (HER2)-positive breast cancer treated by trastuzumab.

METHODS

Fifty-one women with HER2-positive breast cancer treated with trastuzumab plus taxane-based NAC were retrospectively included from January 2005 to December 2015. For ¹⁸F-FDG PET/CT, the analyzed predictor was the maximum standardized uptake value of the primary tumor and axillary nodes after the first course of NAC (PET₂.SUV_max). pCR was defined by no residual infiltrative tumor but in situ tumor was accepted. Accuracy of CGFL/Curie nomogram and PET₂.SUV_max was evaluated measuring sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV). Combined prediction was evaluated testing predictor's associations.

RESULTS

For CGFL/Curie nomogram's performances, Se, Sp, PPV and NPV were respectively: 76% (95%CI: 58-90%), 57% (95%CI: 43-66%), 55% (95%CI: 42-65), 77% (95%CI: 59-90%). For PET₂.SUV_max's performances, Se, Sp, PPV and NPV were respectively: 67% (95%CI: 48-81%), 77% (95%CI: 64-97%), 67% (95%CI: 48-82%), 77% (95%CI: 64-87%). ROC curves for these predictors were similar; the areas under the curve were 0.6 (95%CI: 0.56-0.64) for PET₂.SUV_max and 0.55 (95%CI: 0.50-0.59) for CGFL/Curie nomogram. Combined prediction was efficient with Se at 80%, VPN at 76%, Sp at 78% and VPP at 81%.

CONCLUSIONS

CGFL/Curie nomogram and PET₂.SUV_max were two efficient predictors of pCR in patients with HER2-positive breast cancer. Combined prediction has an improved accuracy.

Shear-driven phase transformation in silicon nanowires

We report on an unprecedented formation of allotrope heterostructured Si nanowires by plastic deformation based on applied radial compressive stresses inside a surrounding matrix. Si nanowires with a standard diamond structure (3C) undergo a phase transformation toward the hexagonal 2H-allotrope. The transformation is thermally activated above 500 °C and is clearly driven by a shear-stress relief occurring in parallel shear bands lying on {115} planes. We have studied the influence of temperature and axial orientation of nanowires. The observations are consistent with a martensitic phase transformation, but the finding leads to clear evidence of a different mechanism of deformation-induced phase transformation in Si nanowires with respect to their bulk counterpart. Our process provides a route to study shear-driven phase transformation at the nanoscale in Si.

A New Model to Study the Role of Arachidonic Acid in Colon Cancer Pathophysiology

A significant increase in cyclooxygenase 2 (COX2) gene expression has been shown to promote cylcooxygenase-dependent colon cancer development. Controversy associated with the role of COX2 inhibitors indicates that additional work is needed to elucidate the effects of arachidonic acid (AA)-derived (cyclooxygenase and lipoxygenase) eicosanoids in cancer initiation, progression, and metastasis. We have recently developed a novel Fads1 knockout mouse model that allows for the investigation of AA-dependent eicosanoid deficiency without the complication of essential fatty acid deficiency. Interestingly, the survival rate of Fads1-null mice is severely compromised after 2 months on a semi-purified AA-free diet, which precludes long-term chemoprevention studies. Therefore, in this study, dietary AA levels were titrated to determine the minimal level required for survival, while maintaining a distinct AA-deficient phenotype. Null mice supplemented with AA (0.1%, 0.4%, 0.6%, 2.0%, w/w) in the diet exhibited a dose-dependent increase (P < 0.05) in AA, PGE2, 6-keto PGF1α, TXB2, and EdU-positive proliferative cells in the colon. In subsequent experiments, null mice supplemented with 0.6% AA diet were injected with a colon-specific carcinogen (azoxymethane) in order to assess cancer susceptibility. Null mice exhibited significantly (P < 0.05) reduced levels/multiplicity of aberrant crypt foci (ACF) as compared with wild-type sibling littermate control mice. These data indicate that (i) basal/minimal dietary AA supplementation (0.6%) expands the utility of the Fads1-null mouse model for long-term cancer prevention studies and (ii) that AA content in the colonic epithelium modulates colon cancer risk. Cancer Prev Res; 9(9); 750-7. ©2016 AACR.

Influence of Ergometer Design on Physiological Responses during Rowing

The aim of this study was to compare the physiological responses and rowing efficiency on 2 different rowing ergometers: stationary vs. dynamic ergometers manufactured by Concept2. 11 oarswomen and oarsmen rowed 4 min at 60% and 70% of peak power output on both ergometers (randomized order). Power output, stroke rate, heart rate, oxygen uptake, carbon dioxide production, lactate accumulation and rating of perceived exertion were recorded at each stage on the 2 ergometers. Gross and net efficiencies were computed. Exercise intensity was associated with increases in all parameters. Rowing on dynamic ergometer was associated with higher heart rate, oxygen uptake, carbon dioxide production and stroke rate, concomitantly to lower blood lactate accumulation but also to lower gross and net efficiencies. The present study showed that rowing efficiency and blood lactate accumulation were lower on the Concept2 dynamic ergometer than on its stationary counterpart. If the use of the Concept2 dynamic ergometer may provide some advantages (reduced risk of injuries), its utilization requires a specific evaluation of physiological responses during an incremental exercise for an adapted management of training.

Comparison of outcomes after unrelated cord blood and unmanipulated haploidentical stem cell transplantation in adults with acute leukemia

Outcomes after unmanipulated haploidentical stem cell transplantation (Haplo) and after unrelated cord blood transplantation (UCBT) are encouraging and have become alternative options to treat patients with high-risk acute leukemia without human leukocyte antigen (HLA) matched donor. We compared outcomes after UCBT and Haplo in adults with de novo acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Median follow-up was 24 months. Analysis was performed separately for patients with AML, n=918 (Haplo=360, UCBT=558) and ALL, n=528 (Haplo=158 and UCBT=370). UCBT was associated with delayed engraftment and higher graft failure in both AML and ALL recipients. In multivariate analysis, UCBT was associated with lower incidence of chronic graft-vs-host disease both in the AML group (hazard ratio (HR)=0.63, P=0.008) and in the ALL group (HR=0.58, P=0.01). Not statistically significant differences were observed between Haplo and UCBT for relapse incidence (HR=0.95, P=0.76 for AML and HR=0.82, P=0.31 for ALL), non-relapse mortality (HR=1.16, P=0.47 for AML and HR=1.23, P=0.23 for ALL) and leukemia-free survival (HR 0.78, P=0.78 for AML and HR=1.00, P=0.84 for ALL). There were no statistically differences on main outcomes after unmanipulated Haplo and UCBT, and both approaches are valid for acute leukemia patients lacking a HLA matched donor. Both strategies expand the donor pool for patients in need.

Morphine stimulates cancer progression and mast cell activation and impairs survival in transgenic mice with breast cancer

BACKGROUND

Morphine stimulates angiogenesis and cancer progression in mice. We investigated whether morphine influences tumour onset, development, and animal model survival, and whether µ-opioid receptor (MOR), lymphangiogenesis, mast cell activation, and substance P (SP) are associated with the tumour-promoting effects of morphine.

METHODS

Transgenic mice with a rat C3(1) simian virus 40 large tumour antigen fusion gene which demonstrate the developmental spectrum of human infiltrating ductal breast carcinoma were used. Mice were treated at different ages with clinically relevant doses of morphine or phosphate-buffered saline to determine the effect on tumour development and progression, and on mouse survival. Tumours were analysed for MOR, angiogenesis, lymphangiogenesis, SP, and mast cell activation by immunofluorescent- or laser scanning confocal-microscopy. Cytokine and SP levels were determined by enzyme-linked immunosorbent assay.

RESULTS

Morphine did not influence tumour development when given before the onset of tumour appearance, but significantly promoted progression of established tumours, and reduced survival. MOR-immunoreactivity (ir) was observed in larger but not in smaller tumours. Morphine treatment resulted in increased tumour angiogenesis, peri-tumoural lymphangiogenesis, mast cell activation, and higher levels of cytokines and SP in tumours. SP-ir co-localized with mast cells and elsewhere in the tumours.

CONCLUSIONS

Morphine does not affect the onset of tumour development, but it promotes growth of existing tumours, and reduces overall survival in mice. MOR may be associated with morphine-induced cancer progression, resulting in shorter survival. Mast cell activation by morphine may contribute to increased cytokine and SP levels, leading to cancer progression and refractory pain.

Nonverbal and verbal cognitive discrepancy profiles in autism spectrum disorders: influence of age and gender

Research suggests that discrepant cognitive abilities are more common in children with autism spectrum disorder (ASD) and may indicate an important ASD endophenotype. The current study examined the frequency of IQ discrepancy profiles (nonverbal IQ > verbal IQ [NVIQ > VIQ], verbal IQ > nonverbal IQ [VIQ > NVIQ], and no split) and the relationship of gender, age, and ASD symptomatology to IQ discrepancy profile in a large sample of children with ASD. The NVIQ > VIQ profile occurred at a higher frequency than expected, had more young males, and showed more autism symptoms than the other groups. Results suggest that the NVIQ > VIQ profile may be less likely to represent a subtype of ASD, but rather a common developmental pathway for children with ASD and other disorders.

Composition and local strain mapping in Au-catalyzed axial Si/Ge nanowires

For most applications, heterostructures in nanowires (NWs) with lattice mismatched materials are required and promise certain advantages thanks to lateral strain relaxation. The formation of Si/Ge axial heterojunctions is a challenging task to obtain straight, defect free and extended NWs. And the control of the interface will determine the future device properties. This paper reports the growth and analysis of NWs consisting of an axial Si/Ge heterostructure grown by a vapor-liquid-solid process. The composition gradient and the strain distribution at the heterointerface were measured by advanced quantitative electron microscopy methods with a resolution at the nanometer scale. The transition from pure Ge to pure Si shows an exponential slope with a transition width of 21 nm for a NW diameter of 31 nm. Although diffuse, the heterointerface makes possible strain engineering along the axis of the NW. The interface is dislocation-free and a tensile out-of-plane strain is noticeable in the Ge section of the NW, indicating a lattice accommodation. Experimental results were compared to finite element calculations.

Hemolysis induced by an extreme mountain ultra-marathon is not associated with a decrease in total red blood cell volume

Prolonged running is known to induce hemolysis. It has been suggested that hemolysis may lead to a significant loss of red blood cells; however, its actual impact on the erythrocyte pool is unknown. Here, we test the hypothesis that prolonged running with high hemolytic potential decreases total red blood cell volume (RCV). Hemolysis (n = 22) and RCV (n = 19) were quantified in ultra-marathon runners before and after a 166-km long mountain ultra-endurance marathon (RUN) with 9500 m of altitude gain/loss. Assessment of total hemoglobin mass (Hbmass) and RCV was performed using a carbon monoxide rebreathing technique. RUN induced a marked acute-phase response and promoted hemolysis, as shown by a decrease in serum haptoglobin (P < 0.05). Elevated serum erythropoietin concentration and reticulocyte count after RUN were indicative of erythropoietic stimulation. Following RUN, runners experienced hemodilution, mediated by a large plasma volume expansion and associated with a large increase in plasma aldosterone. However, neither Hbmass nor RCV were found to be altered after RUN. Our findings indicate that mechanical/physiological stress associated with RUN promotes hemolysis but this has no impact on total erythrocyte volume. We therefore suggest that exercise 'anemia' is entirely due to plasma volume expansion and not to a concomitant decrease in RCV.

Characterization of an arachidonic acid-deficient (Fads1 knockout) mouse model

Arachidonic acid (20:4(Δ5,8,11,14), AA)-derived eicosanoids regulate inflammation and promote cancer development. Previous studies have targeted prostaglandin enzymes in an attempt to modulate AA metabolism. However, due to safety concerns surrounding the use of pharmaceutical agents designed to target Ptgs2 (cyclooxygenase 2) and its downstream targets, it is important to identify new targets upstream of Ptgs2. Therefore, we determined the utility of antagonizing tissue AA levels as a novel approach to suppressing AA-derived eicosanoids. Systemic disruption of the Fads1 (Δ5 desaturase) gene reciprocally altered the levels of dihomo-γ-linolenic acid (20:3(Δ8,11,14), DGLA) and AA in mouse tissues, resulting in a profound increase in 1-series-derived and a concurrent decrease in 2-series-derived prostaglandins. The lack of AA-derived eicosanoids, e.g., PGE₂ was associated with perturbed intestinal crypt proliferation, immune cell homeostasis, and a heightened sensitivity to acute inflammatory challenge. In addition, null mice failed to thrive, dying off by 12 weeks of age. Dietary supplementation with AA extended the longevity of null mice to levels comparable to wild-type mice. We propose that this new mouse model will expand our understanding of how AA and its metabolites mediate inflammation and promote malignant transformation, with the eventual goal of identifying new drug targets upstream of Ptgs2.

Vasculogenic mimicry of acute leukemic bone marrow stromal cells

Angiogenesis is thought to be involved in the development of acute leukemia (AL). We investigated whether bone marrow stromal cells (BMSCs) derived from stem cells might be responsible for the increase in microvascular density (MVD), and compared 13 bone marrow samples from AL patients with 23 samples from patients in complete remission (controls). We demonstrated that AL-derived BMSC secreted more insulin growth factor-1 (IGF-1) and SDF-1alpha than controls. In addition, in contrast to normal adherent BMSCs, adherent BMSCs derived from CD133+/CD34+ stem cells from AL patients were able to form capillary-like structures ('vasculogenic mimicry') on Matrigel. The increase in vasculogenic mimicry occurred through PI3 kinase and rho GTPase pathway as inhibitors of these signaling pathways (wortmannin and GGTI-298, respectively) were able to reduce or prevent capillary tube formation. In normal BMSC, addition of exogenous IGF-1 generated capillary-like tubes through the same pathway as observed spontaneously in AL-derived BMSC. The involvement of IGF-1 in the mimicry process was confirmed by the addition of a neutralizing antibody against IGF-1R or a IGF-1R pathway inhibitor (picropodophyllin). In conclusion, AL-derived BMSC present functional abnormalities that may explain the increase in MVD in the bone marrow of AL patients.

[Immediate reactions to local anesthetics: diagnostic and therapeutic procedures]

BACKGROUND

Despite the widespread use of local anesthetics and frequently reported adverse reactions, true IgE-mediated allergy to local anesthetics is extremely rare. We report on 80 patients seen in our department for adverse reactions to local anesthetics, and we propose a clinical strategy to confirm or rule out immediate allergy to local anesthetics.

PATIENTS AND METHODS

We retrospectively analyzed the medical files of all patients referred to our department by their doctor or dentist for suspected immediate allergic reaction to local anesthetics between September 2001 and May 2004. These patients underwent skin tests (prick test and intradermal tests) exploring immediate allergy.

RESULTS

Eighty cases were tested in our department during this period. The most common symptoms were facial edema or dizziness following injection of an anesthetic occurring between a few seconds and more than 48 hours after administration. The causative local anesthetics were of the amide group in 91% of cases and of the ester group in 9% of cases. Seventy-nine patients had negative skin tests, allowing us to eliminate the diagnosis of immediate allergy, and the anesthetic could be reinjected with good tolerability. One patient presented with positive skin tests to lidocaine and cross reactivity to mepivacaine.

COMMENTS

Adverse reactions to local anesthetics are common and are mostly of pharmacological or toxic origin. However, allergic accidents with local anesthetics are rare and are mostly of type IV involving specific T cells. Immediate allergy to local anesthetics remains extremely rare with less than 10 authentic documented cases being published to date. Skin tests offer a reliable method for exploring immediate allergy in our experience and we propose a diagnostic strategy to confirm or rule out immediate allergy to local anesthetics.

Activation of FGFR1beta signaling pathway promotes survival, migration and resistance to chemotherapy in acute myeloid leukemia cells

Fibroblast growth factors (FGFs) are important regulators of hematopoiesis and have been implicated in the tumorigenesis of solid tumors. Recent evidence suggests that FGF signaling through FGF receptors (FGFRs) may play a role in the proliferation of subsets of acute myeloid leukemias (AMLs). However, the precise mechanism and specific FGF receptors that support leukemic cell growth are not known. We show that FGF-2, through activation of FGFR1beta signaling, promotes survival, proliferation and migration of AML cells. Stimulation of FGFR1beta results in phosphoinositide 3-kinase (PI3-K)/Akt activation and inhibits chemotherapy-induced apoptosis of leukemic cells. Neutralizing FGFR1-specific antibody abrogates the physiologic and chemoprotective effects of FGF-2/FGFR1beta signaling and inhibits tumor growth in mice xenotransplanted with human AML. These data suggest that activation of FGF-2/FGFR1beta supports progression and chemoresistance in subsets of AML. Therefore, FGFR1 targeting may be of therapeutic benefit in subsets of AML.

Mineralocorticoid hormones exert dramatic effects on pluripotent human stem cell progeny

The authors studied mineralocorticoid receptor (MCR)-mediated effects of steroids on CD34(+) progenitor cells. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis showed the presence of mRNA for both the MCR and the alpha subunit of the epithelial sodium channel, a member of the amiloride-sensitive sodium channel (ASSC) superfamily, in human CD41(+) megacaryoblastic cells derived from cultured bone marrow CD34(+) isolates, as well as in the human erythromegakaryoblastic leukemia (HEL) cell line. Immunofluorescence also revealed the presence of both the MCR and ASSC in circulating CD34(+) and medullar CD41(+) megacaryoblastic cells, the former as a nucleocytoplasmic protein and the latter as a membrane-bound protein, as expected from earlier studies using MCR-specific targets. In a selective medium, the formation of erythrocyte burst-forming units, and of the granulocyte-macrophage colony-forming units, by circulating CD34(+) cells was influenced by the agonists deoxycorticosterone and aldosterone, as well as by the antagonists RU 26752 and ZK 91587, targeted for the MCR. The multiplication of the leukemic HEL progeny, derived from CD41(+) cells, was similarly altered by these steroids targeted for the MCR. In contrast, in the optimal growth medium, the multiplication, and colony formation by bone marrow CD34(+) progenitor cells were not altered by either aldosterone or ZK 91587. These and other studies reveal that the receptor-mediated action of mineralocorticoids may influence the functional maturation of the hematopoietic progenitor lineage, contrary to the classical notion where the mineralotropic effect would be a unique feature of the epithelial cell.

Acute renal failure in the tropics: emerging trends from a tertiary care hospital in South India

AIM

To study epidemiology, laboratory parameters, outcome and factors determining outcome of patients presenting with acute renal failure in our hospital.

MATERIALS AND METHODS

A prospective study between December 1997-December 1999 in which all patients presenting with acute renal failure were included. Demographics, laboratory parameters, etiology, outcome and prognostic factors determining outcome were studied.

RESULTS

642 patients were part of the study. The predominant underlying cause for ARF was sepsis (153/642); overall mortality was 26.5%. Patients who had sepsis were admitted in the ICU, and patients with oliguria had poorer outcome.

CONCLUSION

Sepsis continues to be the predominant cause of ARF. Overall mortality of our patients is better, because of the case mix, a large percentage of patients had acute gastroenteritis as a cause of CRF.