Seroprevalence of trypanosomosis and associated risk factors in cattle from coast and amazonian provinces of Ecuador.

Trypanosomosis is a tropical disease caused by various protozoan haemoparasites, which affects wild and domestic animals, the latter ones related to worldwide livestock production systems. Species such as Trypanosoma vivax and Trypanosoma evansi have been described using serological and molecular tools in several countries from South and Central America. However, Ecuador presents a relevant knowledge gap in the associated general epidemiology and risk factors of the disease. Therefore, the objective of this study was to determine the seroprevalence of trypanosomosis in cattle from different regions of Ecuador. 745 serum samples from 7 Coastal and 3 Amazon provinces were screened for IgG anti-Trypanosoma spp. antibodies, using an in-house indirect ELISA. The seropositivity was explored and associated with several variables such as sex, age, breed, region, management, and province, using statistical tools. The general seroprevalence of trypanosomosis was 19.1% (95% CI: 16.30-22.1%). The Amazonian provinces of Sucumbíos and Napo and the Coastal province of Esmeraldas presented the highest seroprevalence values of 36.7% (95% CI: 27.67-46.47%), 23.64% (95% CI: 16.06-32.68%) and 25% (95% CI: 15.99-35.94%), respectively. Statistical significance was found for the region, province, and management variables, indicating as relevant risk factors the extensive management and Amazon location of the cattle analyzed. Specific actions should be taken to identify the exact species on reservoirs and susceptible hosts, evaluate the implication of farm management and cattle movement as risk factors, and implement surveillance and treatment plans for affected herds.

Molecular identification of Trypanosoma theileri in cattle from the Ecuadorian Amazon.

Trypanosoma theileri is a cosmopolitan opportunistic haemoparasite described in wild and domestic ruminants, and also in arthropod vectors. The presence of this parasite has been reported in several South American countries, including Amazonian regions. Despite the importance of livestock production, Ecuador possesses scarce studies about trypanosomosis and no T. theileri reports in its territory. Here, we showed molecular evidences of the presence of T. theileri in cattle from a province located in the Ecuadorian Amazon. Bovine blood samples were collected from 2014 to 2019, during campaigns to detect haemoparasites in the Ecuadorian provinces of Orellana and Sucumbíos. DNA was extracted from the buffy coat and used in PCR assays with three different molecular markers, ITS1, 18S and Cathepsin L-like. T. theileri was detected only in the Sucumbíos province, with a specific molecular prevalence of 8.6% (3/35) using the three primers and an additional animal detected as positive (11.4% prevalence) only by the ITS1 marker. DNA sequences derived from the generated amplicons were subjected to phylogenetics maximum parsimony and maximum likelihood analysis, which indicate the presence of TthI and TthII genotypes circulating in the evaluated animals. Molecular surveillance should be continually implemented in Ecuador in order to deepen the epidemiological and evolutionary knowledge about T. theileri as well other haemoparasites in the amazon parts of the country.

Effect of supplementation with vitamins D3 and K2 on undercarboxylated osteocalcin and insulin serum levels in patients with type 2 diabetes mellitus: a randomized, double-blind, clinical trial.

BACKGROUND: Patients with type 2 diabetes mellitus (T2DM) are characterized by chronic hyperglycemia as a consequence of decreased insulin sensitivity, which contributes to bone demineralization and could also be related to changes in serum levels of osteocalcin and insulin, particularly when coupled with a deficiency in the daily consumption of vitamins D3 and K2. The objective of this study was to evaluate the effect of vitamin D3 and vitamin K2 supplements alone or in combination on osteocalcin levels and metabolic parameters in patients with T2DM. METHODS: A double-blind, randomized clinical trial was carried out in 40 patients aged between 30 and 70 years old for 3 months. Clinical and laboratory assessment was carried out at the beginning and at the end of the treatment. The patients were divided into three groups: (a) 1000 IU vitamin D3 + a calcinated magnesium placebo (n = 16), (b) 100 µg of Vitamin K2 + a calcinated magnesium placebo (n = 12), and (c) 1000 IU vitamin D3 + 100 µg vitamin K2 (n = 12). RESULTS: After treatment in the total studied population, a significant decrease in glycemia (p = 0.001), HOMA-IR (Homeostatic model assessment-insulin resistance) (p = 0.040), percentage of pancreatic beta cells (p < 0.001), uOC/cOC index and diastolic blood pressure (p = 0.030) were observed; in vitamin D3 group, differences in serum undercarboxylated osteocalcin (p = 0.026), undercarboxylated to carboxylated osteocalcin index (uOC/cOC) (p = 0.039) glucose (p < 0.001) and  % of functional pancreatic beta cells (p < 0.001) were demonstrated. In vitamin K2 group a significant decrease in glycemia (p = 0.002), HOMA-IR (p = 0.041), percentage of pancreatic beta cells (p = 0.002), and in cOC (p = 0.041) were observed, conversely cOC concentration was found high. Finally, in the vitamins D3 + K2 a significant decrease in glycemia (p = 0.002), percentage of pancreatic beta cells (p = 0.004), and in the uOC/cOC index (p = 0.023) were observed. CONCLUSION: Individual or combined supplementation with vitamins D3 and K2 significantly decreases the glucose levels and  % of functional pancreatic beta cells, while D3 and D3 + K2 treatments also induced a reduction in the uOC/cOC index. Only in the group with vitamin D3 supplementation, it was observed a reduction in undercarboxylated osteocalcin while vitamin K2 increased the carboxylated osteocalcin levels.Trial registration NCT04041492.

Una revisión de técnicas básicas de neuroimagen para el diagnóstico de enfermedades neurodegenerativas / A review of basic neuroimaging techniques in diagnosis of neurodegenerative diseases

RESUMEN Actualmente los trastornos neurodegenerativos representan un grave problema de salud pública con una prevalencia en ascenso mundial, si bien se ha tratado de armonizar criterios de diagnóstico para estas enfermedades, aún existen obstáculos que dificultan su correcta diferenciación, dando lugar a errores posteriores en etapas terapéuticas. El objeto de esta revisión pretende mostrar el potencial de tres técnicas de neuroimagen (tomografía por emisión de positrones, resonancia magnética de difusión, resonancia magnética estructural), en la identificación de biomarcadores que apoyen el proceso diagnóstico, en tres de las afecciones neurodegenerativas más comunes (enfermedad de Alzheimer, deterioro cognitivo leve, demencia frontotemporal). Se realizó una revisión mediante búsqueda electrónica de literatura. Se destaca el uso de bases de datos como ScienceDirect, PubMed, SciELO, IEEE, para localizar información sobre hallazgos estructurales y funcionales representativos y el poder diagnóstico de estas técnicas. Como lo confirman los estudios, las neuroimágenes ponen en evidencia su potencial para el establecimiento de patrones en la diferenciación de trastornos neurodegenerativos. La resonancia magnética estructural permanece como herramienta central de diagnóstico, en la identificación de patrones de atrofia corticales y subcorticales. Por otro lado, los avances en la tomografía por emisión de positrones han abierto la puerta a un diagnóstico ante-mortem, y una identificación preclínica temprana. Asimismo, el enfoque reciente de la resonancia magnética de difusión posibilita la caracterización de la integridad microestructural de la materia blanca cerebral y su relación con el deterioro cognitivo en el contexto de la enfermedad neurodegenerativa. Al integrar información de diferentes dominios se apoya las herramientas clínicamente aceptadas, garantizando mejor precisión del diagnóstico y la predicción de la aparición de la enfermedad. Los resultados demuestran que, a través de enfoques multimodales, colaboraciones multicentro, armonización de las metodologías y parámetros de adquisición, es posible incluir estas herramientas en el arsenal clínico para la identificación de estas enfermedades.

ABSTRACT Currently, neurodegenerative disorders represent a serious public health problem, with an increasing prevalence worldwide. Even though there has been an attempt to harmonize the diagnostic criteria for these disorders, there are still obstacles that hinder their correct differentiation, leading to subsequent errors in therapeutic stages. This review aims to demonstrate the potential of three neuroimaging techniques (positron emission tomography, diffusion-weighted magnetic resonance, and structural magnetic resonance) in the identification of discriminating biomarkers that support the diagnostic process in three of the most common neurodegenerative disorders (Alzheimer's disease, Mild Cognitive Impairment, frontotemporal dementia). A review was done via an electronic literature search. The use of ScienceDirect, PubMed, SciELO, and IEEE databases to find information on representative structural and functional findings, as well as the diagnostic power of these techniques, is highlighted. As the studies confirm, neuroimages show their potential to establish patterns in the differentiation of neurodegenerative disorders. The structural magnetic resonance remains as a central tool in the identification of cortical and subcortical atrophy patterns. On the other hand, advances in positron emission tomography have enabled not only antemortem diagnosis but also early preclinical identification. Likewise, the recent approach of diffusion magnetic resonance allows to characterizing the microstructural integrity of the cerebral white matter and its relationship with cognitive deterioration in the context of the neurodegenerative disorder. By integrating information from different domains, the clinically accepted tools are supported, guaranteeing better diagnostic accuracy and the prediction of the onset of the disorder. The results show that through multimodal approaches, multicenter collaborations, harmonization of methodologies and acquisition parameters it is possible to include these tools in the clinical repertoire for the identification of these disorders.

Type 2 diabetes detection based on serum sample Raman spectroscopy.

In this work, we propose to the Raman spectroscopy as a new technique for the detection of the type 2 diabetes using blood serum samples. The serum samples were obtained from 15 patients who were clinically diagnosed with type 2 diabetes mellitus and 20 healthy volunteers. The average spectra showed equally intense peaks as, 695 cm-1, the doublet of tyrosine at 828 and 853 cm-1, phenylalanine at 1002 and 1028 cm-1, the phospholipid shoulder at 1300-1345 cm-1, and proteins (amide I) at 1654 cm-1. The major differences were found at 661 and 1404 cm-1 (glutathione), 714 (polysaccharides), 605 (Phe), 545 cm-1 (tryptophan), and the shoulder of amide III at 1230-1282 cm-1, where seem to disappear in the diabetes spectrum. On the contrary, the region that is more highlighted due to that diabetes peaks are clearly more intense was 897-955 cm-1. Principal component analysis and linear discriminate analysis were employed for developing discrimination method. The first three principal components provided a classification of the samples from healthy and diabetes patients with high sensitivity and specificity. In addition, when the first principal component was plotted as a function of the Raman shift, it revealed these shifts accounted for the greatest differences between control and diabetes samples, which coincided with the shifts of spectral differences shown by mean spectra. Our results demonstrated that serum sample Raman spectroscopy promises to become a non-invasive support tool of the currently applied techniques for type 2 diabetes detection, decreasing the false-positive cases.

RAD51 foci as a functional biomarker of homologous recombination repair and PARP inhibitor resistance in germline BRCA-mutated breast cancer.

Background: BRCA1 and BRCA2 (BRCA1/2)-deficient tumors display impaired homologous recombination repair (HRR) and enhanced sensitivity to DNA damaging agents or to poly(ADP-ribose) polymerase (PARP) inhibitors (PARPi). Their efficacy in germline BRCA1/2 (gBRCA1/2)-mutated metastatic breast cancers has been recently confirmed in clinical trials. Numerous mechanisms of PARPi resistance have been described, whose clinical relevance in gBRCA-mutated breast cancer is unknown. This highlights the need to identify functional biomarkers to better predict PARPi sensitivity. Patients and methods: We investigated the in vivo mechanisms of PARPi resistance in gBRCA1 patient-derived tumor xenografts (PDXs) exhibiting differential response to PARPi. Analysis included exome sequencing and immunostaining of DNA damage response proteins to functionally evaluate HRR. Findings were validated in a retrospective sample set from gBRCA1/2-cancer patients treated with PARPi. Results: RAD51 nuclear foci, a surrogate marker of HRR functionality, were the only common feature in PDX and patient samples with primary or acquired PARPi resistance. Consistently, low RAD51 was associated with objective response to PARPi. Evaluation of the RAD51 biomarker in untreated tumors was feasible due to endogenous DNA damage. In PARPi-resistant gBRCA1 PDXs, genetic analysis found no in-frame secondary mutations, but BRCA1 hypomorphic proteins in 60% of the models, TP53BP1-loss in 20% and RAD51-amplification in one sample, none mutually exclusive. Conversely, one of three PARPi-resistant gBRCA2 tumors displayed BRCA2 restoration by exome sequencing. In PDXs, PARPi resistance could be reverted upon combination of a PARPi with an ataxia-telangiectasia mutated (ATM) inhibitor. Conclusion: Detection of RAD51 foci in gBRCA tumors correlates with PARPi resistance regardless of the underlying mechanism restoring HRR function. This is a promising biomarker to be used in the clinic to better select patients for PARPi therapy. Our study also supports the clinical development of PARPi combinations such as those with ATM inhibitors.

CARDIOVASCULAR RISK FACTORS IN ADOLESCENTS: ROLE OF INSULIN RESISTANCE AND OBESITY.

INTRODUCTION: Childhood obesity is a public health problem characterized by early insulin resistance (IR), inflammation, and oxidative stress. The presence of an uninterrupted low-grade inflammatory state impairs metabolic and cardiovascular health. The population is particularly susceptible to develop metabolic disorders related to increased body fat. METHODS: Eighty-three adolescents were recruited and grouped according to HOMA-IR and BMI in either with or without IR and obese or normal-weight respectively. Anthropometric, biochemical, immunological and hormonal variables were determined. Transverse Analytical Study. RESULTS: Obesity, dyslipidemia, IL-6, and C-reactive protein were significantly higher in the IR group than in the non-IR group. Obese adolescents showed increased insulin levels, HOMA-IR, inflammatory markers, and triglycerides; while having lower HDL-C, and adiponectin when compared to normal-weight adolescents. As expected, obesity-related anthropometric markers positively correlated with IR and inflammatory markers while negatively correlated with adiponectin levels. CONCLUSIONS: Early IR, subclinical inflammation, dyslipidemia, and hypoadiponectinemia characterize obesity in adolescents. These factors may increase the risk of future coronary heart disease (CHD) and diabetes mellitus development (DM) in early adulthood.

Facilitated Engraftment of Isolated Islets Coated With Expanded Vascular Endothelial Cells for Islet Transplantation.

BACKGROUND: Diabetes is complex disease, which involves primary metabolic changes followed by immunological and vascular pathophysiological adjustments. However, it is mostly characterized by an unbalanced decreased number of the ß-cells unable to maintain the metabolic requirements and failure to further regenerate newly functional pancreatic islets. The objective of this study was to analyze the properties of the endothelial cells to facilitate the islet cells engraftment after islet transplantation. METHODS: We devised a co-cultured engineer system to coat isolated islets with vascular endothelial cells. To assess the cell integration of cell-engineered islets, we stained them for endothelial marker CD31 and nuclei counterstained with DAPI dye. We comparatively performed islet transplantations into streptozotocin-induced diabetic mice and recovered the islet grafts for morphometric analyses on days 3, 7, 10, and 30. Blood glucose levels were measured continuously after islet transplantation to monitor the functional engraftment and capacity to achieve metabolic control. RESULTS: Cell-engineered islets showed a well-defined rounded shape after co-culture when compared with native isolated islets. Furthermore, the number of CD31-positive cells layered on the islet surface showed a direct proportion with engraftment capacities and less TUNEL-positive cells on days 3 and 7 after transplantation. CONCLUSIONS: We observed that vascular endothelial cells could be functional integrated into isolated islets. We also found that islets that are coated with vascular endothelial cells increased their capacity to engraft. These findings indicate that islets coated with endothelial cells have a greater capacity of engraftment and thus establish a definitely vascular network to support the metabolic requirements.

Germline BRCA testing is moving from cancer risk assessment to a predictive biomarker for targeting cancer therapeutics.

PURPOSE: Originally, BRCA testing was used for risk assessment and prevention strategies for breast and ovarian cancer. Nowadays, BRCA status may influence therapeutic decision making at cancer diagnosis. Our objective was to analyze whether the medical advances have changed the burden and pattern of referral, and the pathogenic mutation detection rate. METHODS: We included 969 probands from our hereditary cancer registry who undertook a full BRCA analysis between 2006 and 2014. Chi-square tests were used to compare categorical variables. RESULTS: The number of genetic tests have raised from 28 to 170, representing a sixfold increase. In 2006, we tested 1.6 relatives/proband while this proportion was four in 2014. Overall, 20 % harbored a deleterious mutation and 11 % had a variant of unknown significance (VUS). There has been a downward trend in the detection rate of VUS. Testing patients with breast cancer during neoadjuvancy has raised from 4 to 25 % (p = 0.002), while testing them during remission has decreased from 79 to 29 % (p < 0.001). The proportion of patients assessed during the first 6 months after their cancer diagnosis has increased from 3 to 34 % (p = 0.001). Risk reducing mastectomy and salpingoophorectomy have raised from 0 to 24 %, and from 36 to 65 %, respectively. CONCLUSIONS: BRCA testing has experienced a sixfold increase, the number of relatives being tested has doubled, and the test is being performed at earlier phases of the disease. It is necessary to adequate the health resources to preserve the BRCA genetic counseling quality while incorporating BRCA testing for therapeutic decision making.

Single-chamber ICD, single-zone therapy in primary and secondary prevention patients: the simpler the better?

BACKGROUND: It is now well established that implantable cardioverter defibrillator (ICD) implantation reduces mortality in patients at increased risk of sudden cardiac death. However, the best programming parameters remain controversial. Our traditional policy has followed a simple approach in the vast majority of patients. In accordance with ICD programming in the major randomized clinical trials, we programmed a single high-rate, shock-only therapy zone. We aimed to demonstrate in this observational study that simple programming is not associated with higher shock rates or mortality when compared to other published studies. METHODS: Consecutive patients who underwent single-chamber ICD implantation with single-zone, high-rate programming at our institution between 1993 and 2008 were retrospectively studied. Data were collected prospectively in a database regarding details of ICD implantation, demographic data, and indication. RESULTS: Three hundred thirty-two patients were included in our study, 31 % primary prevention and 68 % secondary prevention. Mean ejection fraction (EF) is 33.7 ± 15.3. Over a mean follow-up period of 62.5 ± 38.1 months, 135 patients experienced ICD shock (annualized event rate 7.7 %); 89 patients (26.8 %) appropriate shock in VT-ventricular fibrillation (VF), 68 patients (20.5 %) inappropriate shocks, and 22 patients (6.6 %) both. Twenty-nine patients (8.7 %) were reprogrammed to additional VT-ATP zones. Twenty-two (6.6 %) patients underwent heart transplantation. Sixty-two patients (18.6 %) died during follow-up, 43.6 % out of them due to cardiac cause, mainly progressive heart failure. CONCLUSION: Our results show that simpler settings with single-zone, high-rate programming is associated with ICD shock rates and long-term mortality that does not appear to be worse when compared with contemporary studies which include multizone ICD programming with antitachycardia pacing activated.

Germline ATM mutational analysis in BRCA1/BRCA2 negative hereditary breast cancer families by MALDI-TOF mass spectrometry.

Biallelic inactivation of ATM gene causes the rare autosomal recessive disorder Ataxia-telangiectasia (A-T). Female relatives of A-T patients have a two-fold higher risk of developing breast cancer (BC) compared with the general population. ATM mutation carrier identification is laborious and expensive, therefore, a more rapid and directed strategy for ATM mutation profiling is needed. We designed a case-control study to determine the prevalence of 32 known ATM mutations causing A-T in Spanish population in 323 BRCA1/BRCA2 negative hereditary breast cancer (HBC) cases and 625 matched Spanish controls. For the detection of the 32 ATM mutations we used the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry technique. We identified one patient carrier of the c.8264_8268delATAAG ATM mutation. This mutation was not found in the 625 controls. These results suggest a low frequency of these 32 A-T causing mutations in the HBC cases in our population. Further case-control studies analyzing the entire coding and flanking sequences of the ATM gene are warranted in Spanish BC patients to know its implication in BC predisposition.

Atrial flutter after heart transplantation: mechanism and catheter ablation.

BACKGROUND: Atrial flutter is a frequent arrhythmia after heart transplantation, but little is known about its mechanism and treatment. We report the results of an electrophysiologic study in patients with atrial flutter after orthotopic heart transplantation, describing its mechanism and demonstrating the acute and long-term efficacy of catheter ablation for treating this arrhythmia. METHODS: We included 14 patients with symptomatic atrial flutter after orthotopic heart transplantation. All of them underwent an electrophysiologic study to determine the mechanism of the arrhythmia and catheter ablation when possible. RESULTS: Counterclockwise right atrial circuit around the tricuspid annulus involving the cavotricuspid isthmus was demonstrated in 13 patients (86%). Catheter ablation of the isthmus was performed with good acute results in all but 1. During a mean follow-up of 24 ± 17 months, recurrent atrial flutter was documented in 3 patients and atrial fibrillation in 2. In another patient, we demonstrated a left atrial origin. CONCLUSIONS: The most common mechanism of atrial flutter in heart transplant recipients is a counterclockwise circuit around the tricuspid annulus involving the cavotricuspid isthmus. Catheter ablation of the isthmus between tricuspid annulus and posterior atrial suture line represents an effective treatment in these patients. This condition may be avoided by changing the surgical technique to a bicaval anastomosis.

Effects of Hibiscus sabdariffa extract powder and preventive treatment (diet) on the lipid profiles of patients with metabolic syndrome (MeSy).

Insulin resistance, obesity, hypertension, and dyslipidemia are strongly associated with metabolic syndrome (MeSy), which is considered to be a reversible clinical stage before its evolution to coronary heart disease and diabetes. Currently, the antihypertensive and hypolipidemic properties of aqueous Hibiscus sabdariffa extracts (HSE) have been demonstrated in clinical trials and in vivo experiments. The aim of the present study was to evaluate the effects of a Hibiscus sabdariffa extract powder (HSEP) and a recognized preventive treatment (diet) on the lipid profiles of individuals with and without MeSy according to the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) criteria. The protocol was a follow-up study carried out in a factorial, randomized design (T1=preventive treatment comprises Diet, T2=HSEP, T3=HSEP+preventive treatment (Diet) X MeSy, non-MeSy individuals). A total daily dose of 100 mg HSEP was orally administered in capsules for one month. The preventive treatment (diet) was selected according to NCEP-ATP III recommendations and adjusted individually. Total cholesterol, LDL-c, HDL-c, VLDL-c, triglycerides, glucose, urea, creatinine, AST, and ALT levels in the blood were determined in all individuals pre- and post-treatment. The MeSy patients treated with HSEP had significantly reduced glucose and total cholesterol levels, increased HDL-c levels, and an improved TAG/HDL-c ratio, a marker of insulin resistance (t-test p<0.05). Additionally, a triglyceride-lowering effect was observed in MeSy patients treated with HSEP plus diet, and in individuals without MeSy treated with HSEP. Significant differences in total cholesterol, HDL-c, and the TAG/HDL-c ratio were found when the means of absolute differences among treatments were compared (ANOVA p<0.02). Therefore, in addition to the well documented hypotensive effects of Hibiscus sabdariffa, we suggest the use of HSEP in individuals with dyslipidemia associated with MeSy.

Mechanical performance and in vivo tests of an acrylic bone cement filled with bioactive sepia officinalis cuttlebone.

To promote osteointegration, bioactive cuttlebone particles containing collagen were used to fill an acrylic cement, varying filler concentration (0-50 wt%). Cuttlebone was characterized by X-ray diffraction, plasma atomic emission and FT-IR. Mechanical properties of the filled cement were determined following ASTM procedures, included stress-strain, compression, bending, and fracture toughness tests. For in vivo tests, three groups of seven adult healthy rabbits were prepared to make an implant in the parietal bone of each one. For such groups (I-III), the amount of filler in the cement was 0, 10 and 30 wt%, respectively. Mechanical results for the composites complied with norm requirements. However, as mechanical performance for composite with 50 wt% of filler decreased significantly, for the in vivo tests, such composite was excluded. In vivo tests showed that three implants of group I were loosely attached to the parietal bone, whereas all the implants made with cement containing cuttlebone particles (groups II and III) were firmly attached to the parietal bone, indicating osteointegration. These results clearly show the potential of this type of bioactive filler to be used for medical applications.

NF-kappa B is required for the development of tumor spheroids.

Tumor cells cultured in three-dimensional models provide a more realistic and biologically meaningful analysis of the initial phases of cancer development and drug resistance. Several studies have demonstrated that culture of cancer cells in three dimensions induces cellular resistance to a variety of anti-neoplastic drugs by poorly understood mechanisms. The role of the transcription factor NF-kappaB and inhibitors of apoptosis proteins (IAPs) in the onset and development of drug resistance during tumor spheroid growth has not been established. In this work, we found a significant increase in the activity and expression of NF-kappaB and its downstream target XIAP (X-linked IAP) in cancer cells grown as multi-cellular tumor spheroids. Blocking XIAP expression with RNA interference markedly increased the sensitivity of cancer tumor spheroid cells toward anti-neoplastic drugs, indicating a role for IAPs in establishing drug resistance. In turn, inhibition of NF-kappaB by negative dominants suppressed spheroid formation, whereas overexpression of the upstream kinase IkappaBKbeta increased their growth and resistance. The present data suggested that NF-kappaB and its downstream target XIAP were essential for the growth and drug resistance of small avascular tumor.

ATM germline mutations in Spanish early-onset breast cancer patients negative for BRCA1/BRCA2 mutations.

Heterozygous carriers of ATM (ataxia telangiectasia mutated gene) mutations have increased risk of breast cancer (BC). We have estimated the prevalence of mutations in the ATM gene among Spanish patients with early-onset BC. Forty-three patients diagnosed with BC before the age of 46 years, and negative for BRCA1 and BRCA2 mutations, were analysed for the presence of ATM mutations. A total of 34 ATM sequence variants were detected: 1 deleterious mutation, 10 unclassified variants and 23 polymorphisms. One patient (2.3%) carried the ATM deleterious mutation (3802delG that causes ataxia telangiectasia in the homozygous state) and 13 patients carried the 10 ATM unclassified variants. The truncating mutation 3802delG and eight of the rare variants were not detected in a control group of 150 individuals. Different bioinformatic sequence analysis tools were used to evaluate the effects of the unclassified ATM changes on RNA splicing and function protein. This in silico analysis predicted that the missense variants 7653 T>C and 8156 G>A could alter the splicing by disrupting an exonic splicing enhancer motif and the 3763 T>G, 6314 G>C, and 8156 G>A variants would affect the ATM protein function. These are the initial results concerning the prevalence of germline mutations in the ATM gene among BC cases in a Spanish population, and they suggest that ATM mutations can confer increased susceptibility to early-onset BC.

Metabolic changes induced by cold stress in rat liver mitochondria.

The mechanisms involved in the metabolic changes induced by cold stress in isolated rat liver mitochondria were studied. Respiration, ATP synthesis, and membrane potential as well as the contents of several metabolites were determined in liver mitochondria from cold-exposed rats. At different times of cold exposure, the force-flux relationships showed net variation in flux (enhanced respiration, diminished ATP synthesis) with no associated variation in force (H+ gradient); this suggested that decoupling rather than classical uncoupling was involved in the effects of cold stress. The flux control coefficient of the H+ leak on basal respiration was slightly increased by 380 h of cold exposure. Cold stress also induced a diminution in total membrane fatty acids, Zn2+, Fe3+, ATP, and ADP/O ratios; the content of cytochromes c + c1 and b oscillated. The contents of Ca2+, Na+, Pi, and cytochromes a + a3 were not affected, whereas matrix ADP, AMP, K+, and Mg2+ were markedly increased. Basal and oleic acid-stimulated respiration of mitochondria from cold-stressed rats was inhibited by GDP, carboxyatractyloside, or albumin. These agents did not affect basal respiration in control mitochondria. Western blot analysis showed enhanced expression of a protein of about 35 kDa, presumably the uncoupling protein 2, induced by long-term cold exposure. The overall data suggest that cold stress promoted decoupling of oxidative phosphorylation, and hence, changes in several matrix metabolites, by increasing free fatty acids and the UCP2 content.

[Unstable angina in octogenarians: is an invasive approach feasible and effective?]. / Angina inestable en el paciente octogenario: ¿es factible y eficaz el abordaje invasivo?

BACKGROUND AND OBJECTIVE: Octogenarian patients with unstable angina are usually managed more conservatively despite having a worse prognosis. Studies of balloon angioplasty in the elderly have demonstrated a higher incidence of adverse events but the new advances (mainly stenting) have improved the results. We evaluated the efficacy and safety of an invasive approach in octogenarians with unstable angina. PATIENTS AND METHOD: From January 1996 to October 1999, 100 patients at least 80 years old with unstable angina were admitted to our unit and among these, 74 (74%) underwent percutaneous revascularization. We evaluated immediate results, in-hospital events and clinical follow-up. RESULTS: A total of 145 lesions were treated in 74 patients. The stent implantation rate was 79%. The success rate was 92%. Two patients died during hospitalization due to cardiac causes and 1 patient had a non-Q infarction. At follow-up, 24 +/- 12 months (range: 4 -50 months) 14 patients died (19.4%). New revascularization was performed in 10 patients (13.5%), 9 with PTCA and 1 with surgery. The survival rate free of death and infarction in the first year was 89.2%. At the end of follow-up 58 patients were alive (78.4%), 45 asymptomatic and 13 had stable angina, class I or II. CONCLUSIONS: The results of stent implantation in octogenarians were good with a 92% procedural success. Ninety-six percent of patients were free of death and infarction during hospitalization and 78.4% of the patients remained alive, most of them asymptomatic at the end of follow-up.