Valproic acid radiosensitizes anaplastic thyroid cells through a decrease of the DNA damage repair capacity.

BACKGROUND: Anaplastic thyroid cancer (ATC) represents a rare lethal human malignancy with poor prognosis. Multimodality treatment, including radiotherapy, is recommended to improve local control and survival. Valproic acid (VA) is a clinically available histone deacetylase inhibitor with a well-documented side effect profile. In this study, we aim to investigate the combined effect of VA with photon irradiation in vitro. METHODS: Anaplastic thyroid cancer cells (8505c) were used to investigate the radiosensitizing effect of VA. RESULTS: VA sensitized cells to photon irradiation. VA increased radiation-induced apoptosis and radiation-induced DNA damage measured by γH2AX foci induction. Furthermore, VA prolonged γH2AX foci disappearance over time in irradiated cells and decreased the radiation-induced levels of mRNA of key DNA damage repair proteins of the homologous recombination (HR) and the nonhomologous end joining (NHEJ) pathways. CONCLUSIONS: VA at a clinically safe dose enhance the radiosensitivity of 8505c cells through an increase in radiation-induced apoptosis and a disruption in the molecular mechanism of HR and NHEJ DNA damage repair pathways.

Generation, establishment and characterization of a pluripotent stem cell line (CVTTHi001-A) from primary fibroblasts isolated from a patient with activated PI3 kinase delta syndrome (APDS2).

APDS2 is caused by mutations in PIK3R1 gene resulting in constitutive PI3Kδ activation. PI3Kδ is predominantly expressed in leukocytes and plays critical roles in regulating immune responses. Here we first derived fibroblast primary cells from a skin biopsy of a patient carrying a heterozygous single T deletion in intron 11 of the PIK3R1 gene. We next present the derivation of an induced pluripotent stem cell (iPS) line using a non-integrative reprogramming technology. Pluripotent-related hallmarks are further shown, including: iPSCs self-renewal and expression of pluripotent and differentiation markers after in vitro differentiation towards embryonic germ layers, assessed by RT-PCR and immunofluorescence.

Chain-Branched Polyhydroxylated Octahydro-1H-Indoles as Potential Leads against Lysosomal Storage Diseases.

Here, the synthesis and glycosidase inhibition properties of the two first known 3-ethyloctahydro-1H-indole-4,5,6-triols are reported. This study shows the transformation of d-glucose into polyhydroxylated 1-(2-nitrocyclohexane) acetaldehydes, followed by a protocol involving the formation of the azacyclopentane ring. Results of inhibitory potency assays and docking calculations show that at least one of them could be a lead for optimization in the search for compounds that behave like folding chaperones in lysosomal storage diseases.

Environmental Effects Determine the Structure of Potential ß-Amino Acid Based Foldamers.

This work shows that hybrid peptides formed by alternating trans-2-aminocyclopentanecarboxylic acid (trans-ACPC) and trans-2-aminocyclohexanecarboxylic acid (trans-ACHC) do not fold in the solvents typically used in the study of their homo-oligomers. Only when the peptides are assayed in SDS micelles are the predicted helical structures obtained. This indicates that the environment could play an equally important role (as the backbone stereochemistry) in determining their fold, possibly by providing a sequestered environment.

The Philippines health system review

The Asia Pacific Observatory on Health Systems and Policies (the APO) is a collaborative partnership of interested governments, international agencies, foundations, and researchers that promotes evidence-informed health systems policy regionally and in all countries in the Asia Pacific region. The APO collaboratively identifies priority health system issues across the Asia Pacific region; develops and synthesizes relevant research to support and inform countries' evidence-based policy development; and builds country and regional health systems research and evidence-informed policy capacity.

Tumor de células esteroideas sin otra especificación: reporte de un caso / Steroid cell tumour, not otherwise specified (NOS): A case report

Los tumores de ovario de células esteroideas constituyen una entidad infrecuente de virilización. Pueden originarse del estoma o de los cordones sexuales; en ocasiones el linaje tumoral es desconocido, denominándose tumor esteroide no especificado. Presentamos el caso de una paciente con signos de virilización rápidamente progresiva, sugestivo de origen ovárico. Las pruebas de imágenes fueron negativas, y tras ser sometida a intervención quirúrgica se objetivó la presencia de un tumor microscópico con marcadores positivos para células esteroideas

Ovarian steroid cell tumours are an uncommon cause of virilisation. They may originate from the stroma or sex cords; sometimes the tumour lineage is unknown, in which case the tumour is described as ‘not otherwise specified’. We report the case of a patient with signs of rapidly progressive virilisation, suggestive of ovarian origin. Imaging tests were negative. After surgical intervention, the presence of microscopic tumour markers positive for steroid cells was observed

Computer-aided structure-based design of multitarget leads for Alzheimer's disease.

Alzheimer's disease is a neurodegenerative pathology with unmet clinical needs. A highly desirable approach to this syndrome would be to find a single lead that could bind to some or all of the selected biomolecules that participate in the amyloid cascade, the most accepted route for Alzheimer disease genesis. In order to circumvent the challenge posed by the sizable differences in the binding sites of the molecular targets, we propose a computer-assisted protocol based on a pharmacophore and a set of required interactions with the targets that allows for the automated screening of candidates. We used a combination of docking and molecular dynamics protocols in order to discard nonbinders, optimize the best candidates, and provide a rationale for their potential as inhibitors. To provide a proof of concept, we proceeded to screen the literature and databases, a task that allowed us to identify a set of carbazole-containing compounds that initially showed affinity only for the cholinergic targets in our experimental assays. Two cycles of design based on our protocol led to a new set of analogues that were synthesized and assayed. The assay results revealed that the designed inhibitors had improved affinities for BACE-1 by more than 3 orders of magnitude and also displayed amyloid aggregation inhibition and affinity for AChE and BuChE, a result that led us to a group of multitarget amyloid cascade inhibitors that also could have a positive effect at the cholinergic level.

Effect of pH and ligand charge state on BACE-1 fragment docking performance.

In this work we propose a protocol for estimating the effect of pH on the docking performance to BACE-1, which affords the charge state of the inhibitor as well as the protonation state of all ionisable residues in the protein at a given pH value. To the best of our knowledge, this is the first report of a protocol predicting the BACE-1 ligand docking poses not only at the neutral pH at which most crystallographic structures were obtained, but also at the optimal pH of the enzyme (in the acidic range), at which most of the BACE-1 binding affinity assays are performed. We have applied this protocol to a set of 23 fragment-like BACE-1 ligands that span four orders of magnitude in their binding affinities. The pK a values of the BACE-1 acidic residues deviate substantially from the estimates for model compounds in solution and display a ligand dependent variability, especially in the case of the catalytic Asp dyad residues. This outcome should have a strong bearing on the design of protocols for docking based BACE-1 screening campaigns. Finally, we were able to find an explanation for the poor docking success rate of some fragments based on the availability of anchoring points, a rationale that could help to improve hit rates in BACE-1 screening campaigns.

On the active site protonation state in aspartic proteases: implications for drug design.

Aspartic proteases (AP) are a family of important hydrolytic enzymes in medicinal chemistry, since many of its members have become therapeutical targets for a wide variety of diseases from AIDS to Alzheimer. The enzymatic activity of these proteins is driven by the Asp dyad, a pair of active site Asp residues that participate in the hydrolysis of peptides. Hence, the protonation state of these and other acidic residues present in these enzymes determines the catalytic rate and the affinity for an inhibitor at a given pH. In the present work we have reviewed the effect of the protonation states of the titratable residues in AP's both on catalysis and inhibition in this family of enzymes. The first section focuses on the details of the catalytic reaction mechanism picture brought about by a large number of kinetic, crystallographic and computational chemistry analyses. The results indicate that although the mechanism is similar in both retroviral and eukaryotic enzymes, there are some clear differences. For instance, while in the former family branch the binding of the substrate induces a mono-ionic charge state for the Asp dyad, this charge state seems to be already present in the unbound state of the eukaryotic enzymes. In this section we have explored as well the possible existence of low barrier hydrogen bonds (LBHB's) in the enzymatic path. Catalytic rate enhancement in AP's could in part be explained by the lowering of the barrier for proton transfer in a hydrogen bond from donor to acceptor, which is a typical feature of LBHB's. Review of the published work indicates that the experimental support for this type of bonds is rather scarce and it may be more probable in the first stages of the hydrolytic mechanism in retroviral proteases. The second section deals with the effect of active site protonation state on inhibitor binding. The design of highly potent AP inhibitors, that could be the basis for drug leads require a deep knowledge of the protonation state of the active site residues induced by their presence. This vital issue has been tackled by experimental techniques like NMR, X-ray crystallography, calorimetric and binding kinetic techniques. Recently, we have developed a protocol that combines monitoring the pH effect on binding affinities by SPR methods and rationalization of the results by molecular mechanics based calculations. We have used this combined method on BACE-1 and HIV-1 PR, two important therapeutic targets. Our calculations are able to reproduce the inhibitor binding trends to either enzyme upon a pH increase. The results indicate that inhibitors that differ in the Asp dyad binding fragments will present different binding affinity trends upon a pH increase. Our calculations have enabled us to predict the protonation states at different pH values that underlie the above mentioned trends. We have found out that these results have many implications not only for in silico hit screening campaigns aimed at finding high affinity binders, but also (in the case of BACE-1) for the discovery of cell active compounds.

Experimental and 'in silico' analysis of the effect of pH on HIV-1 protease inhibitor affinity: implications for the charge state of the protein ionogenic groups.

The pH dependence of the HIV-1 protease inhibitor affinity was studied by determining the interaction kinetics of a series of inhibitors at three pH values by surface plasmon resonance (SPR) biosensor analysis. The results were rationalized by molecular mechanics based protocols that have as a starting point the structures of the HIV-1 protease inhibitor complexes differing in the protonation states as predicted by our calculations. The SPR experiments indicate a variety of binding affinity pH dependencies which are rather well reproduced by our simulations. Moreover, our calculations are able to pinpoint the possible changes in the charged state of the protein binding site and of the inhibitor that underlie the observed effects of the pH on binding affinity. The combination of SPR and molecular mechanics calculations has afforded novel insights into the pH dependence of inhibitor interactions with their target. This work raises the possibility of designing inhibitors with different pH binding affinity profiles to the ones described here.

Interferon-ß lipofection II. Mechanisms involved in cell death and bystander effect induced by cationic lipid-mediated interferon-ß gene transfer to human tumor cells.

We evaluated the cytotoxic effects (apoptosis, necrosis and early senescence) of human interferon-ß (hIFNß) gene lipofection. The cytotoxicity of hIFNß gene lipofection resulted equivalent to that of the corresponding addition of the recombinant protein (rhIFNß) on human tumor cell lines derived from Ewing's sarcoma (EW7 and COH) and colon (HT-29) carcinomas. However, it was stronger than rhIFNß on melanoma (M8) and breast adenocarcinoma (MCF7). To reveal the mechanisms involved in these differences, we compared the effects of hIFNß gene and rhIFNß protein on EW7 and M8 (sensitive and resistant to rhIFNß protein, respectively). Lipofection with hIFNß gene caused a mitochondrial potential decrease simultaneous with an increase of oxidative stress in both cell lines. However, rhIFNß protein displayed the same pattern of response only in EW7-sensitive cell line. The great bystander effect of the hIFNß gene lipofection, involving the production of reactive oxygen species, would be among the main causes of its success. In EW7, this effect killed >60% of EW7 cell population, even though only 1% of cells were expressing the transgene. As hIFNß gene was effective even in the rhIFNß protein-resistant M8 cell line and in a way not limited by low lipofection efficiency, these results strongly support the clinical potential of this approach.

Interferon-ß lipofection I. Increased efficacy of chemotherapeutic drugs on human tumor cells derived monolayers and spheroids.

We evaluated the effect of hIFNß gene transfer alone or in combination with different antineoplastic drugs commonly used in cancer treatment. Five human tumor-derived cell lines were cultured as monolayers and spheroids. Four cell lines (Ewing sarcomas EW7 and COH, melanoma M8 and mammary carcinoma MCF-7) were sensitive to hIFNß gene lipofection. Although this effect appeared in both culture configurations, spheroids showed a relative multicellular resistance (insensitive colon carcinoma HT-29 excluded). EW7 and M8 hIFNß-expressing cells were exposed to different concentrations of bleomycin, bortezomib, carboplatin, doxorubicin, etoposide, methotrexate, paclitaxel and vincristine in both configuration models. In chemotherapy-sensitive EW7 monolayers, the combination of hIFNß gene and antineoplastic drugs displayed only additive or counteractive (methotrexate) effects, suggesting that cytotoxic mechanisms triggered by hIFNß gene lipofection could be saturating the signaling pathways. Conversely, in chemotherapy-resistant EW7 spheroids or M8 cells, the combination of hIFNß with drugs that mainly operate at the genotoxic level (doxorubicin, methotrexate and paclitaxel) presented only additive effects. However, drugs that also increase pro-oxidant species can complement the antitumor efficacy of the hIFNß gene and clearly caused potentiated effects (bleomycin, bortezomib, carboplatin, etoposide and vincristine). The great bystander effect induced by hIFNß gene lipofection could be among the main causes of its effectiveness, because only 1 or 2% of EW7 or M8 hIFNß-expressing cells killed more than 60 or 80% of cell population, respectively.

Cytotoxic and genotoxic effects of defence secretion of Ulomoides dermestoides on A549 cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Ulomoides dermestoides (Fairmaire, 1893) is a cosmopolitan tenebrionid beetle reared by Argentine people who consume them alive as an alternative medicine in the treatment of different illnesses such as asthma, Parkinson's, diabetes, arthritis, HIV and specially cancer. AIM OF THE STUDY: To evaluate the cytotoxicity and DNA damage of the major volatile components released by Ulomoides dermestoides on human lung carcinoma epithelial cell line A549. MATERIALS AND METHODS: The defence compounds of Ulomoides dermestoides were extracted with dichloromethane and analyzed and quantified by capillary gas chromatography. The toxicity effects of the beetle's extract against A549 cell line were evaluated. Cytotoxicity was evaluated by MTT test and Trypan blue assay and genotoxicity was evaluated by the comet assay. The synthetic compounds, individually or combined, were also tested in A549 cells and normal mononuclear human cells. RESULTS: The defence compounds of Ulomoides dermestoides extracted with dichloromethane (methyl-1,4-benzoquinones, ethyl-1,4-benzoquinones and 1-pentadecene as major components) showed cytotoxic activity on A549 cells demonstrated by MTT test and Trypan blue assay, with IC(50) values of 0.26equivalent/ml and 0.34equivalent/ml, respectively (1equivalent=amount of components extracted per beetle). The inhibition of A549 cell proliferation with the synthetic blend (1,4-benzoquinone and 1-pentadecene) or 1,4-benzoquinone alone was similar to that obtained with the insect extract. 1-Pentadecene showed no inhibitory effect. Low doses of insect extract or synthetic blend (0.15equivalent/ml) inhibited mononuclear cell proliferation by 72.2±2.7% and induced significant DNA damage both in tumor and mononuclear cells. CONCLUSION: Results of this study demonstrated that defence compounds of Ulomoides dermestoides reduced cell viability and induced DNA damage. We also concluded that the insect benzoquinones are primarily responsible for inducing cytotoxicity and genotoxicity in culture cells.

On a possible neutral charge state for the catalytic dyad in ß-secretase when bound to hydroxyethylene transition state analogue inhibitors.

ß-Secretase is one of the aspartic proteases involved in the formation of amyloid plaques in Alzheimer's disease patients. Our previous results using a combination of surface plasmon resonance experiments with molecular modeling calculations suggested that the Asp dyad in ß-secretase bound to hydroxylethylene containing inhibitors adopts a neutral charged state. In this work, we show that the Asp dyad diprotonated state reproduced the binding ranking of a set of these inhibitors better than alternative protonation states.

Beauveria bassiana infection alters colony development and defensive secretions of the beetles Tribolium castaneum and Ulomoides dermestoides (Coleoptera: Tenebrionidae).

We studied the effect of the entomopathogenic fungus Beauveria bassiana strain GHA on a) colony development of the beetles Tribolium castaneum (Herbst) and Ulomoides dermestoides (Fairmaire) (Coleoptera: Tenebrionidae) under laboratory conditions; and 2) the volatile blend released by both beetles, containing defensive pheromones, by using the solid phase microextraction technique. Colony development of both species was strongly altered 3 mo after treatment with B. bassiana, showing a significant reduction in progeny of 37.5% for T. castaneum and 50.0% for U. dermestoides. We also showed that the volatiles released by T. castaneum diminished close to 20% compared with those of healthy beetles, whereas in U. dermestoides secretions dramatically dropped to 5%, 7 d after immersion in 1 x 10(9) conidia per ml. These results suggest that after infection events take place, fungus-induced diminished secretion of the defensive pheromones may be a physiologic clue for behavioral changes in infected beetles.

Effect of the protonation state of the titratable residues on the inhibitor affinity to BACE-1.

BACE-1 is one of the aspartic proteases involved in the cleavage of beta amyloid peptide, an initial step in the formation of amyloid plaques whose toxicity induces neuron death in Alzheimer's disease patients. One of the central issues in the search of novel BACE-1 inhibitors is the optimum pH for the binding of inhibitors to the enzyme. It is known that the enzyme has optimal catalytic activity at acidic pH, while cell active inhibitors may bind optimally at higher pH. In this work we determine the effect of the pH on the affinities of a set of inhibitors, with a variety of chemical motifs, for the ectodomain region of BACE-1 by a surface plasmon resonance (SPR) biosensor based assay. In order to understand the molecular interactions that underlie the diverse optimum pH for the binding of the various inhibitors as observed experimentally, we have calculated the titration curves for a set of BACE-1 ligand complexes. The results indicate that the pK(a) values of the titratable residues of the protein depend on the nature of the ligand involved, in disagreement with previous work. The enzyme-inhibitor structures with the resulting protonation states at pH values 4.5 and 7.4 served as the starting point for the prediction of the pH-dependent binding ranking. Our calculations reproduced the entire affinity ranking observed upon pH increase and most of the binding trends among inhibitors, especially at low pH. Finally, our cell-based assays indicate a possible correlation between high inhibitor affinity at both acidic and neutral pH values, with optimal cell response, a result that may open new venues for the search of potent BACE-1 inhibitors that are active at the cellular level.

Factors predicting mortality in elderly patients on dialysis.

UNLABELLED: Elderly patients are increasingly enrolled in dialysis programs and present a series of special characteristics due to their high morbidity and mortality. OBJECTIVE: To describe the characteristics of incident dialysis patients aged >75 years, their comorbidities and their admissions, with a view to determining the factors that influence their course and mortality. PATIENTS AND METHODS: The study included all patients aged >75 years who started dialysis in our center since January 2000. The mean duration of follow-up was 3.3 +/- 2.2 years. Data were collected on incident comorbidity, admissions and their causes. A total of 139 patients were included, with a mean age of 78.6 +/- 2.6 years (67.6% males, 33.8% diabetic and 7.9% on peritoneal dialysis). Three groups were established according to age: 75-79, 80-85 and >85 years. The most frequent comorbidities were chronic obstructive pulmonary disease (25.9%), ischemic heart disease (25.2%), heart failure (25.9%), neoplasms (23.7%), peripheral vascular disease (23.7%), cerebrovascular disease (18.7%) and arterial hypertension (81%). The Charlson index was calculated, not adjusted for age, and comorbidity tertiles were established. RESULTS: During follow-up, the patients presented 0.82 +/- 0.99 admissions/patient/year, with a duration of 12.1 +/- 20.6 days/patient/year. The main causes of admission were infection (33%), vascular access problems (27%) and peripheral vascular events (14%). A total of 61 patients died (44%), and 4 underwent kidney transplantation (2.9%). The mean duration of follow-up of the transplanted patients was 3.6 +/- 1.8 years. The main causes of death were infection (32%), cardiovascular problems (28.3%) and neoplastic disease (11.3%). The global survival rate was 90, 82 and 53% after 1, 2 and 5 years, respectively. No significant differences in survival or annual admission rate were found in relation to age group and dialysis technique. In contrast, the annual admission rate and days of admission were directly correlated to the Charlson index (p = 0.009 and p = 0.032, respectively). No significant differences in the Charlson index were found between the patients on hemodialysis and those subjected to peritoneal dialysis. In the univariate model, the factors associated to mortality were diabetes, chronic obstructive pulmonary disease, heart failure and the Charlson index. In the multivariate model, only the Charlson index remained as an independent predictive factor (p = 0.006). CONCLUSIONS: Unlike the general population, age does not influence mortality or admissions in elderly patients on dialysis. Incident comorbidity is the factor exerting the greatest influence upon mortality and admissions. Advanced age in itself should not be regarded as an excluding factor for starting dialysis.

Evolución del índice de resistencia a darbepoetina alfa en pacientes dializados que cambian de administración semanal a quincenal en la práctica clínica / Evolution of the darbepoetin alpha resistance index in patients on dialysis who change from weekly to fortnightly treatments in clinical practice

Antecedentes: Diversos estudios han demostrado la eficacia de darbepoetina alfa (DA) administrada quincenalmente (C2S), lo que permite simplificar el tratamiento para la anemia, pero faltan datos acerca de la evolución del índice de resistencia (IRE) tras el espaciamiento desde una frecuencia semanal (CS) en la práctica clínica. Material y métodos: Estudio observacional, multicéntrico, retrospectivo, con 16 semanas de seguimiento, en pacientes dializados estables convertidos de DA CS a C2S. El espaciamiento se realizó según ficha técnica (duplicación de dosis semanal). El cálculo del IRE fue: dosis DA (µg/sem.kg*200)/Hb (g/dl). Se analizó la evolución del IRE mediante un ANOVA multivariado de medidas repetidas, ajustando por variables confusoras. Resultados: Se reclutaron 202 pacientes (137 en hemodiálisis [HD], DA intravenosa, y 65 con diálisis peritoneal [DP], DA subcutánea). La edad media (DE) fue 66 (17) años, y el 61% eran hombres. Se apreció una gran variabilidad intercentro en el IRE basal (coeficiente de variación del 88%, p <0,001 para diferencias entre centros). En el análisis univariado los factores predictores de IRE elevado fueron un bajo nivel de albúmina, la HD, o los antecedentes de enfermedad cardiovascular. Durante el seguimiento, el IRE aumentó ligeramente en los pacientes con HD (9,3 [8,4] basal frente a 11,1 [7,3] a 16 semanas; p <0,05), y se mantuvo estable en los pacientes con DP (6,8 [4,6] frente a 6,7 [4,0], respectivamente; NS). En el análisis multivariado, tras ajustar por los niveles de albúmina y el centro, el IRE global no presentó cambios significativos (media [IC 95%] basal de 10,0 [8,7-11,4] frente a 10,5 [9,3-11,8] a las 16 semanas, cambio ajustado de +0,5 [–0,67; 1,67]; NS). Conclusiones: La conversión de frecuencia semanal a quincenal de DA logró mantener el IRE, con independencia del tipo de diálisis. El análisis multivariado refleja que, una vez ajustado por las variables centro y estado de inflamación/nutricional del paciente, no hay cambios en el IRE en las primeras 16 semanas tras el espaciamiento (AU)

Background: Darbepoetin alfa (DA) administered every-other-week (Q2W) is efficacious and safe for the treatment of anaemia in patients undergoing dialysis. There are no data available regarding the evolution of erythropoietic resistance index (ERI) after conversion from weekly (QW) to Q2W administration of DA in clinical practice. Material and methods: Multicenter, observational, retrospective, 16-weeks study, which included stable patients undergoing dialysis who were converted from DA QW to DA Q2W in clinical practice. Conversion was done according to product specifications (duplicating QW dose). The ERI to DA was calculated by dividing the weekly DA dose per kilogram of weight (µg/wk.kg)*200 by the Hb level (g/dL). ERI evolution with time was evaluated by multivariate repeated measures ANOVA, adjusting for significant covariates. Results: A total of 202 patients were included (137 patients undergoing haemodialysis [HD], intravenous (IV) DA, and 65 patients receiving peritoneal dialysis [PD], subcutaneous DA). Mean (SD) age was 66 (17) years; 61% of patients were men. Large intercentre variability was observed for the ERI at conversion time (coefficient of variation of 88%, p <0.001 for differences between centres). In the univariate analysis, predictor factors for high baseline ERI were low albumin level (r = –0.29; p =0.001), HD (mean ERI of 9.3 [8.4] vs 6.8 [4.6] for PD; p = 0.005), or previous cardiovascular disease (9.9 [8.7] vs 7.4 [6.3] for patients without history; p =0.025). During the follow up, the ERI was slightly increased in HD patients (9.3 [8.4] at conversion vs 11.1 [7.3] at 16 weeks; p <0.05), and remained stable in PD patients (6.8 [4.6] vs 6.7 [4.0], respectively; NS). In the multivariate analysis, there were no significant differences in ERI during the 16 weeks post-conversion after adjusting for albumin levels and centre (adjusted baseline mean [95% CI] of 10.0 [8.7-11.4] vs 10.5 [9.3-11.8] at 16 weeks, adjusted change of +0.5 [–0.67; 1.67] ; NS). After 16 weeks, only 7 patients (3.5%) had discontinued Q2W administration. Conclusions: Extension from weekly to once every-other-week darbepoetin alfa allows to simplify anaemia treatment without increasing the resistance index, regardless of dialysis type. The multivariate analysis shows that, after adjusting by center and inflammation/nutritional status, there were no changes in the response to darbepoetin alfa during the first 16 weeks after conversion in clinical practice (AU)

[Evolution of the darbepoetin alpha resistance index in patients on dialysis who change from weekly to fortnightly treatments in clinical practice]. / Evolución del índice de resistencia a darbepoetina alfa en pacientes dializados que cambian de administración semanal a quincenal en la práctica clínica.

BACKGROUND: Darbepoetin alpha (DA) administered every-other-week (Q2W) is efficacious and safe for the treatment of anaemia in patients undergoing dialysis. There are no data available regarding the evolution of erythropoietic resistance index (ERI) after conversion from weekly (QW) to Q2W administration of DA in clinical practice. MATERIAL AND METHODS: Multicenter, observational, retrospective, 16-weeks study, which included stable patients undergoing dialysis who were converted from DA QW to DA Q2W in clinical practice. Conversion was done according to product specifications (duplicating QW dose). The ERI to DA was calculated by dividing the weekly DA dose per kilogram of weight (microg/wk.kg)*200 by the Hb level (g/dL). ERI evolution with time was evaluated by multivariate repeated measures ANOVA, adjusting for significant covariates. RESULTS: A total of 202 patients were included (137 patients undergoing haemodialysis [HD], intravenous (IV) DA, and 65 patients receiving peritoneal dialysis [PD], subcutaneous DA). Mean (SD) age was 66 (17) years; 61% of patients were men. Large intercentre variability was observed for the ERI at conversion time (coefficient of variation of 88%, p < 0.001 for differences between centres). In the univariate analysis, predictor factors for high baseline ERI were low albumin level (r = -0.29; p =0.001), HD (mean ERI of 9.3 [8.4] vs 6.8 [4.6] for PD; p = 0.005), or previous cardiovascular disease (9.9 [8.7] vs 7.4 [6.3] for patients without history; p =0.025). During the follow up, the ERI was slightly increased in HD patients (9.3 [8.4] at conversion vs 11.1 [7.3] at 16 weeks; p < 0.05), and remained stable in PD patients (6.8 [4.6] vs 6.7 [4.0], respectively; NS). In the multivariate analysis, there were no significant differences in ERI during the 16 weeks post-conversion after adjusting for albumin levels and centre (adjusted baseline mean [95% CI] of 10.0 [8.7-11.4] vs 10.5 [9.3-11.8] at 16 weeks, adjusted change of +0.5 [-0.67; 1.67]; NS). After 16 weeks, only 7 patients (3.5%) had discontinued Q2W administration. CONCLUSIONS: Extension from weekly to once every other-week darbepoetin alpha allows to simplify anaemia treatment without increasing the resistance index, regardless of dialysis type. The multivariate analysis shows that, after adjusting by center and inflammation/nutritional status, there were no changes in the response to darbepoetin alpha during the first 16 weeks after conversion in clinical practice.

Suicide gene therapy on spontaneous canine melanoma: correlations between in vivo tumors and their derived multicell spheroids in vitro.

To validate the use of multicellular spheroids to predict the efficacy of herpes simplex thymidine kinase/ganciclovir (HSVtk/GCV) suicide gene therapy in the respective in vivo tumors, we established and characterized 15 melanoma-derived cell lines from surgically excised melanoma tumors. Three HSVtk-lipofected cell lines were not sensitive to GCV in any culture configuration, other five displayed similar sensitivity as monolayers or spheroids, and only one resulted more sensitive when grown as spheroids. Other six cell lines manifested a relative multicellular resistance (MCR) phenotype growing as spheroids, compared with the same cells growing as monolayers. The reverse correlation between the MCR and the monolayers survival to HSVtk/GCV suggests that one of the main causes of MCR would be the rapid cell repopulation after suicide gene treatment. The high correlation of MCR with the spheroids radial growth and with the mitotic index of the respective originary tumors supported this re-growth involvement. A remarkable finding was the high correlation in HSVtk/GCV sensitivity between in vivo tumor and the corresponding derived cell lines growing as spheroids (R(2) = 0.85). This strongly encourages the implementation of spheroids as highly realistic experimental model for optimizing and predicting the in vivo response of the respective tumors to therapeutic strategies.