Cáncer de mama Her2-positivo: Terapias sistémicas actuales y experiencia local

El cáncer de mama (CM) es la primera causa de muerte por cáncer en mujeres tanto a nivel mundial como en Chile. Basados en características clínicas, histológicas y moleculares, múltiples estudios han identificado cuatro subtipos básicos de CM, los cuales están asociados a estrategias de tratamiento específicas y diferenciadas. El CM HER2-positivo representa un 15%-25% de todas las neoplasias mamarias y se caracteriza por su agresividad, recurrencia temprana y mayor tendencia a presentar compromiso del sistema nervioso central. En las últimas décadas, nuevas terapias dirigidas se han posicionado como el estándar de tratamiento y han cambiado la historia natural de esta enfermedad, transformándola en una enfermedad potencialmente curable incluso en etapas avanzadas. Esta revisión busca entregar un resumen de las bases biológicas de esta enfermedad. Por otro lado, dada la aparición de un creciente número de nuevas estrategias de manejo sistémico, nos proponemos revisar sus mecanismos de acción analizando reportes de datos clínicos publicados y la experiencia de nuestro grupo.

Breast cancer (BC) is the leading cause of cancer death for women both worldwide and in Chile. Based on clinical, histological, and molecular features, studies have identified four BC subtypes that correlate with treatment sensitivity. Human Epidermal growth factor Receptor type 2-positive (HER2+) BC represents 15%-25% of newly diagnosed breast neoplasms; HER2+ BC is characterized by its aggressive behavior, early recurrence, and higher risk of brain metastasis. In recent years, HER2-targeted therapies have become the mainstay of treatment and have redefined the natural history of this subtype, reducing relapse rates for early-stage patients and increasing survival in advanced-stage patients. Herein we review novel treatment strategies and their mechanisms of action, along with clinical and real-world data. We also provide a summary of currently available treatments for this subtype and our local experience regarding the management of this disease.

Genetic polymorphisms and protein levels in vocal fold leukoplakia: a systematic review.

Vocal fold leukoplakia (VFL) has a risk of malignant transformation. Therefore, patients can have symptoms such as dysphonia, vocal strain, difficulty breathing, and dysphagia. Additionally, there is a genetic predisposition that can be associated with genetic polymorphisms. We aimed to evaluate the influence of genetic polymorphisms and protein levels in the etiology of VFL. Our study followed the PRISMA checklist and was registered on PROSPERO database. The questions were: "Are genetic polymorphisms involved in the etiology of VFL? Are protein levels altered in patients with VFL?". Eligibility criteria were case control studies that compared the presence of polymorphisms or/and protein levels of subjects diagnosed with VFL and healthy controls. Of the 905 articles retrieved, five articles with a total of 1038 participants were included in this study. The C allele of the single nucleotide polymorphisms (SNP)-819 T/C IL-10, A allele of the SNP -592 A/C IL-10, CT genotype of the SNP rs11886868 C/T BCL11A, GG genotype of the SNP rs4671393 A/G BCL11A, LL genotype, and L allele of (GT)n repeat polymorphisms of the HO-1 were risk factors for VFL development. Nevertheless, there was a lack of association between VFL and the -1082 A/G IL-10, rs14024 CK-1, and -309 T/G Mdm2 SNPs. The concentrations of the MDM2, BCL11A, and HO-1 proteins were modified, while IL-10 levels were normally expressed in these subjects. In conclusion, most markers evaluated in this review could be potential indicators to develop effective therapies, avoiding a malignant transformation of the lesion.

Genetic polymorphisms and protein levels in vocal fold leukoplakia: a systematic review

Vocal fold leukoplakia (VFL) has a risk of malignant transformation. Therefore, patients can have symptoms such as dysphonia, vocal strain, difficulty breathing, and dysphagia. Additionally, there is a genetic predisposition that can be associated with genetic polymorphisms. We aimed to evaluate the influence of genetic polymorphisms and protein levels in the etiology of VFL. Our study followed the PRISMA checklist and was registered on PROSPERO database. The questions were: "Are genetic polymorphisms involved in the etiology of VFL? Are protein levels altered in patients with VFL?". Eligibility criteria were case control studies that compared the presence of polymorphisms or/and protein levels of subjects diagnosed with VFL and healthy controls. Of the 905 articles retrieved, five articles with a total of 1038 participants were included in this study. The C allele of the single nucleotide polymorphisms (SNP)-819 T/C IL-10, A allele of the SNP -592 A/C IL-10, CT genotype of the SNP rs11886868 C/T BCL11A, GG genotype of the SNP rs4671393 A/G BCL11A, LL genotype, and L allele of (GT)n repeat polymorphisms of the HO-1 were risk factors for VFL development. Nevertheless, there was a lack of association between VFL and the -1082 A/G IL-10, rs14024 CK-1, and -309 T/G Mdm2 SNPs. The concentrations of the MDM2, BCL11A, and HO-1 proteins were modified, while IL-10 levels were normally expressed in these subjects. In conclusion, most markers evaluated in this review could be potential indicators to develop effective therapies, avoiding a malignant transformation of the lesion.

DYNLT1 gene expression is downregulated in whole blood of patients at different Huntington's disease stages.

Huntington's disease (HD) is a neurodegenerative disorder caused by a CAG nucleotide expansion, which encodes the amino acid glutamine, in the huntingtin gene. HD is characterized by motor, cognitive, and psychiatric dysfunctions. In a previous study, we showed by qPCR that some genes altered in an HD mouse model were also altered in blood of HD patients. These alterations were mainly with respect to the dynein family. Therefore, this study aimed to investigate whether dynein light chain Tctex type 1 (DYNLT1) is altered in HD patients and if there is a correlation between DYNLT1 gene expression changes and disease progression. We assessed the DYNLT1 gene expression in the blood of 19 HD patients and 20 healthy age-matched controls. Also, in 6 of these patients, we analyzed the DYNLT1 expression at two time points, 3 years apart. The DYNLT1 gene expression in the whole blood of HD patients was significantly downregulated and this difference was widened in later stages. These data suggest that DYNLT1 could emerge as a peripheral prognostic indicator in HD and, also, might be a target for potential intervention in the future.

Differential gene expression in dairy cows under negative energy balance and ketosis: A systematic review and meta-analysis.

Development of ketosis in high-producing dairy cows contributes to several animal health issues and highlights the need for a better understanding of the genetic basis of metabolic diseases. To evaluate the pattern of differential gene expression in the liver of cows under negative energy balance (NEB), and under subclinical and clinical ketosis, a meta-analysis of gene expression and genome-wide association studies results was performed. An initial systematic review identified 118 articles based on the key words "cow," "liver," "negative energy balance," "ketosis," "expression," "qPCR," "microarray," "proteomic," "RNA-Seq," and "GWAS." After further screening for only peer-reviewed and pertinent articles for gene expression during NEB and clinical and subclinical ketosis (considering plasma levels of ß-hydroxybutyrate), 20 articles were included in the analysis. From the systematic review, 430 significant SNPs identified by genome-wide association studies (GWAS) were assigned to genes reported in gene expression studies by considering chromosome and base pair positions in the ARS-UCD 1.2 bovine assembly. Venn diagrams were created to integrate the data obtained in the systematic review, and Gene Ontology enrichment analysis was carried out using official gene names. A QTL enrichment analysis was also performed to identify potential positional candidate loci. Twenty-four significant SNPs were located within the coordinates of differentially expressed genes located on chromosomes 2, 3, 6, 9, 11, 14, 27, and 29. Three significant metabolic pathways were associated with NEB and subclinical and clinical ketosis. In addition, 2 important genes, PPARA (peroxisome proliferator activated receptor alpha) and ACACA (acetyl-coenzyme A carboxylase α), were identified, which were differentially expressed in the 3 metabolic conditions. The PPARA gene is involved in the regulation of lipid metabolism and fatty liver disease and the ACACA gene encodes an enzyme that catalyzes the carboxylation of acetyl-coenzyme A to malonyl-coenzyme A, which is a rate-limiting step in fatty acid synthesis. Gene network analysis revealed co-expression interactions among 34 genes associated with functions involving fatty acid transport and fatty acid metabolism. For the annotated QTL, 9 QTL were identified for ketosis. The genes FN1 (fibronectin 1) and PTK2 (protein tyrosine kinase 2), which are mainly involved in cell adhesion and formation of extracellular matrix constituents, were enriched for QTL previously associated with the trait "ketosis" on chromosome 2 and for the trait "milk iron content" on chromosome 14, respectively. This integration of gene expression and GWAS data provides an additional understanding of the genetic background of NEB and subclinical and clinical ketosis in dairy cattle. Thus, it is a useful approach to identify biological mechanisms underlying these metabolic conditions in dairy cattle.

Cognitive changes in patient living with HIV-AIDS and apolipoprotein-E polymorphism: is there an association?

Patients with HIV-AIDS treated with antiretroviral drugs still have high prevalence of cognitive disorders and many factors are likely to contribute for ongoing neurologic decline such as chronic low-level infection, coinfections with hepatitis B and C and genetic influences, both the virus and the host. Some evidences suggest that the genetic APOE polymorphism may be an associated risk factor. This study aimed to evaluate the association between APOE polymorphisms and cognitive disorders in patients with HIV-AIDS. This was a cross-sectional study comprising 133 patients aged 19-59 years old, with HIV-AIDS and were assisted at the infectious disease outpatient clinics at Hospital Universitário Oswaldo Cruz, in Recife, Brazil. For cognitive evaluation, Mini-Mental State Examination test (MMSE) and Montreal Cognitive Assessment test (MoCA) were used. The determination of APOE gene polymorphism was performed by using the PCR-RFLP technique. Sociodemographic and clinical characteristics were not significantly associated to APOE ε4 polymorphism, except for the high results of CD4 rate (p < 0.015). There was an absence associated between APOE ε4 polymorphism and neurocognitive tests. This study found no association between cognitive alterations and APOE polymorphism in patients with HIV-AIDS in the Northeast of Brazil. The imbalance of APOE allelic frequency distribution, according to Hardy-Weinberg law, there could be an adjustment phase of its equilibrium suffered by the HIV virus, however, the mechanism is still unknown.

The effect of oblique-angle sputtering on large area deposition: a unidirectional ultrathin Au plasmonic film growth design.

Growing ultrathin nanogranular (NG) metallic films with continuously varying thickness is of great interest for studying regions of criticality and scaling behaviors in the vicinity of quantum phase transitions. In the present work, an ultrathin gold plasmonic NG film was grown on a sapphire substrate by RF magnetron sputtering with an intentional deposition gradient to create a linearly variable thickness ranging from 5 to 13 nm. The aim is to accurately study the electronic phase transition from the quantum tunneling regime to the metallic conduction one. The film structural characterization was performed by means of high-resolution transmission electron microscopy, atomic force microscopy, as well as x-ray diffraction and reflectivity techniques, which indicate the Volmer-Weber film growth mode. The optical and electrical measurements show a transition from dielectric-isolated gold NPs towards a continuous metallic network when t becomes larger than a critical value of tM = 7.8 nm. Our results show that the onset of the percolation region occurs when a localized surface plasma resonance transforms to display a Drude component, indicative of free charge carriers. We demonstrate that, by using a continuously varying thickness, criteria for metallicity can be unambiguously identified. The onset of metallicity is clearly distinguished by the Drude damping factor and by discontinuities in the plasma frequencies as functions of thickness.

An optical-based biosensor of the epithelial sodium channel as a tool for diagnosing hypertension.

Arterial hypertension (HTN) is a world health concern presenting difficulties for its early detection. It leads to cardiovascular and kidney complications that increase morbidity in adults. Overexpression in the epithelial sodium channel (ENaC) in membrane platelets can be related with the presence of HTN and thus can be used as a biomarker to detect this medical condition. Here, we propose a method for HTN diagnosis based on gold nanoparticles (GNPs) conjugated to an antibody against the ENaC present on platelets. These functionalized GNPs were analyzed by Zeta potential, dynamic light scattering, electron microscopy, and other spectroscopic techniques. To verify that the GNPs and α-ENaC antibodies formed conjugates (GNPs-antiENaC) that maintained their specificity to the target, we carried out an indirect immunofluorescence detection assay of GNPs-antiENaC bound to a secondary antibody labeled with a fluorophore. Our results show that the presence of GNPs increase the fluorescence intensity in platelets treated with GNPs-antiENaC conjugates. It is also observed a clear tendency of the fluorescence signal in platelets treated with the conjugates that could be used for discrimination between normotensive and hypertensive samples. The proposed assay can be implemented as a very sensitive routine test to diagnose HTN.

Surveillance of avian influenza and Newcastle disease viruses in backyard poultry raised near migratory bird sites in Mato Grosso state, Brazil.

The Pantanal and Cerrado biomes in the state of Mato Grosso contain migratory bird sites in the municipalities of Cáceres and Araguaiana, respectively. The levels of avian influenza (AI) and Newcastle disease (ND) viral activity in backyard poultry at these sites are unknown owing to a lack of studies. Considering the risk of introduction of AI and ND to Brazil from migratory birds, as well as the importance of active surveillance in the detection and prevention of diseases for official control, monitoring in these poultry populations is faster, more practical and cheaper for official service veterinarians. The objective of this study was to verify the presence of AI and ND viral activity in backyard poultry reared near these migratory bird sites in the years 2016 and 2019. Serum samples and cloacal and tracheal swab samples collected from chickens, turkeys, quails, ducks and geese were evaluated by indirect diagnostic methods including enzyme-linked immunosorbent assay and haemagglutination inhibition tests and direct detection of viral sequences using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). No positive samples were detected by qRT-PCR.The frequencies of birds seropositive for AI and ND were 0.7% and 19.6% in 2016 and 0.5% and 17.2% in 2019, respectively, in Araguaiana and 0.8% and 32.3% in 2016 and 7.0% and 38.1% in 2019, respectively, in Cáceres. Antibodies belonging to AI subtypes H1, H4, H6 and H14 were identified in Cáceres in 2019. Spatial analysis showed an agglomeration of farms with seropositive poultry within the urban area of Cáceres, suggesting AI and ND virus activity in this area. This study showed no circulation of the notifiable AI subtypes H5 and H7 or the ND virus in backyard poultry raised around migratory bird sites in the state of Mato Grosso. The results of the present study support evidence indicating that the circulation of strains with low pathogenicity in urban areas enables backyard poultry to serve as a source of infection for other birds; thus, increased surveillance is necessary in this population.

Les biomes du Pantanal et du Cerrado dans l'état du Mato Grosso contiennent deux sites accueillant des oiseaux migrateurs, situés respectivement dans les comtés de Cáceres et d'Araguaiana. Faute d'études de terrain, le niveau d'activité virale de l'influenza aviaire et de la maladie de Newcastle chez les volailles de basse-cour de ces deux sites était jusqu'à présent inconnu. Compte tenu du risque d'introduction au Brésil de l'influenza aviaire et de la maladie de Newcastle par les oiseaux migrateurs, et de l'importance de la surveillance active pour détecter et prévenir ces maladies dans le cadre des activités de lutte conduites par les Services vétérinaires, il est plus pratique, moins onéreux et plus rapide pour les vétérinaires des services officiels d'axer la surveillance sur les populations de volailles de basse-cour. Les auteurs présentent les résultats d'une étude conduite en 2016 et en 2019 pour déterminer le niveau de circulation des virus de l'influenza aviaire et de la maladie de Newcastle chez les volailles de basse-cour élevées à proximité des sites d'oiseaux migrateurs. Des échantillons sériques et des écouvillons cloacaux et trachéaux prélevés sur des poulets, des dindes, des cailles, des canards et des oies ont été soumis à des méthodes de diagnostic indirectes telles que les épreuves immuno-enzymatique et d'inhibition de l'hémagglutination, et à une méthode de détection directe des séquences virales par amplification en chaîne par polymérase quantitative en temps réel couplée à une transcription inverse (qRT-PCR). Aucun échantillon positif n'a été détecté par qRT-PCR. Les taux de séropositivité respectivement à l'influenza aviaire et à la maladie de Newcastle étaient, chez les volailles prélevées à Araguaiana, de 0,7 % et 19,6 % en 2016, et de 0,5 % et 17,2 % en 2019 ; chez les volailles prélevées à Cáceres, ils étaient de 0,8 % et 32,3 % en 2016, et de 7,0 % et 38,1 % en 2019. Les anticorps détectés à Cáceres en 2019 appartenaient aux sous-types H1, H4, H6 et H14 du virus de l'influenza aviaire. L'analyse spatiale a révélé une concentration importante d'élevages ayant des volailles séropositives dans la zone urbaine de Cáceres, indiquant une activité des virus de l'influenza aviaire et de la maladie de Newcastle dans cette région. Aucune circulation des sous-types H5 et H7 à déclaration obligatoire du virus de l'influenza aviaire ni du virus de la maladie de Newcastle n'a été mise en évidence chez les volailles de basse-cour élevées autour des sites d'oiseaux migrateurs dans l'état du Mato Grosso. Les résultats de cette étude étayent les données d'après lesquelles les volailles de basse-cour des zones urbaines deviennent des sources d'infection pour d'autres espèces d'oiseaux à la faveur d'une circulation de souches faiblement pathogènes ; il est donc nécessaire de renforcer la surveillance dans cette population.

Los biomas de Pantanal y Cerrado, situados en el estado de Mato Grosso, albergan espacios frecuentados por aves migratorias en los municipios de Cáceres y Araguaiana, respectivamente. Debido a la falta de estudios al respecto, se desconocen los niveles de actividad de los virus de la influenza aviar (IA) y de la enfermedad de Newcastle (EN) en las aves de corral caseras de estas zonas. Teniendo en cuenta el riesgo de introducción en el Brasil de la IA y la EN por conducto de aves migratorias, así como la importancia de una vigilancia activa para la detección y prevención de enfermedades con fines de control oficial, para los veterinarios de los servicios públicos resulta más rápido, práctico y barato vigilar esas poblaciones de aves de corral. Los autores describen un estudio encaminado a comprobar, en los años 2016 y 2019, la actividad de los virus de la IA y la EN en bandadas caseras de aves de corral criadas cerca de los antedichos espacios de aves migratorias. Tras obtener muestras séricas e hisopados cloacales y traqueales de pollos, pavos, codornices, patos y gansos, se analizaron las muestras con técnicas de diagnóstico indirecto (ensayo inmunoenzimático y prueba de inhibición de la hemaglutinación) y de detección directa de secuencias víricas (retrotranscripción acoplada a reacción en cadena de la polimerasa cuantitativa en tiempo real: qRT-PCR). No se detectó ninguna muestra positiva por qRT-PCR. En cuanto a las tasas de seropositividad para la IA y la EN, en Araguaiana resultaron positivas el 0,7% y el 19,6%, respectivamente, de las aves analizadas en 2016, por un 0,5% y un 17,2% en 2019, mientras que en Cáceres lo fueron el 0,8% y el 32,3% en 2016 y el 7,0% y el 38,1% en 2019. En 2019 se identificaron en Cáceres anticuerpos correspondientes a los subtipos H1, H4, H6 y H14 del virus de la influenza aviar. El análisis espacial puso de relieve una aglomeración de fincas con aves de corral seropositivas en la zona urbana de Cáceres, hecho indicativo de que en la zona hay actividad de los virus de la IA y la EN. El estudio no evidenció circulación alguna de los subtipos H5 y H7 del virus de la IA, que son de declaración obligatoria, ni del virus de la EN en las aves de corral caseras criadas en los alrededores de los espacios del estado de Mato Grosso que albergan aves migratorias. Los resultados del estudio parecen avalar los datos que indican que la circulación de cepas poco patógenas en zonas urbanas hace de las bandadas caseras una posible fuente de infección para otras aves, razón por cual es tanto más necesario redoblar la vigilancia de estas poblaciones de aves de corral.

Percutaneous endovascular treatment of an iatrogenic superior cava vein syndrome during the immediate post-operative period after mitral-aortic valve replacement. / Tratamiento endovascular percutáneo de un síndrome de vena cava superior en el postoperatorio inmediato de recambio valvular mitroaórtico.

Superior vena cava syndrome (SVCS) results from superior vena cava obstruction, causing a decrease in venous return from the head, neck, and upper extremities. Although the most frequent cause is still malignant tumour processes, in recent years an increase has been observed in non-tumour causes, such as thrombosis of intravascular devices or iatrogenic causes during cardiac surgery. A case is presented of SVCS after cardiac surgery treated satisfactorily by an endovascular technique and systemic anticoagulation.

Double intracardiac thrombosis in a patient assisted by a venoarterial extracorporeal membrane oxygenation. / Trombosis intracardíaca doble en paciente asistido mediante membrana de oxigenación extracorpórea venoarterial.

Intracardiac thrombosis is a rare complication in patients receiving haemodynamic support with venous-arterial extracorporeal membrane oxygenation (VA-ECMO), but it has a high risk of mortality. This case report describes a patient who suffered cardiogenic shock after a ST-segment elevation myocardial infarction (STEMI) and who presented with intracardiac thrombosis during VA-ECMO support on two occasions after mitral valve replacement. The first one was after the insertion of a mechanical prosthesis, and the second, after replacing it with a biological valve.

Interfacial tension measurements using a new axisymmetric drop/bubble shape technique.

This paper introduces a new mathematical model that is used to compute either the interfacial tension of quiescent axisymmetric pendant/sessile drops and pendant/captive bubbles. This model consists of the Young-Laplace equation, that describes interface shape, together with suitable boundary conditions that guarantee a prescribed volume of drops/bubbles and a fixed position in the capillary. In order to solve the problem numerically, the Young-Laplace equation is discretized by using numerical differentiation and the numerical solutions are obtained applying the well-know Newton method. The paper contains a validation of the new methodology presented for what theoretical bubble/drops are used. Finally, some numerical results are presented for both drops and bubbles of water as well as several surfactant solutions to demonstrate the applicability, versatility and reproducibility of the proposed methodology.

Massive right hemothorax due to idiopathic spontaneous rupture of a phrenic artery following cardiac surgery. / Hemotórax masivo derecho por rotura espontánea idiopática de una arteria frénica tras cirugía cardiaca.

We report a case of a 35-years-old man who presented a massive haemothorax and hypovolemic shock following cardiac surgery, from spontaneous rupture of a phrenic artery. A quick diagnosis and immediate intervention is crucial to manage the patient.

Using artificial neural networks to select the parameters for the prognostic of mild cognitive impairment and dementia in elderly individuals.

BACKGROUND AND OBJECTIVES: A huge number of solutions based on computational systems have been recently developed for the classification of cognitive abnormalities in older people, so that individuals at high risk of developing neurodegenerative diseases, such as Cognitive Impairment and Alzheimer?s disease, can be identified before the manifestation of the diseases. Several factors are related to these pathologies, making the diagnostic process a hard problem to solve. This paper proposes a computational model based on the artificial neural network to classify data patterns of older adults. METHODS: The proposal takes into account the several parameters as diagnostic factors as gender, age, the level of education, study time, and scores from cognitive tests (Mini-Mental State Examination, Semantic Verbal Fluency Test, Clinical Dementia Rating and Ascertaining Dementia). This non-linear regression model is designed to classify healthy and pathological aging with machine learning techniques such as neural networks, random forest, SVM, and stochastic gradient boosting. We deployed a simple linear regression model for the sake of comparison. The primary objective is to use a regression model to analyze the data set aiming to check which parameters are necessary to achieve high accuracy in the diagnosis of neurodegenerative disorders. RESULTS: The analysis demonstrated that the usage of cognitive tests produces median values for the accuracy greater than 90%. The ROC analysis shows that the best sensitivity performance is above 98% and specificity of 96% when the configurations have only cognitive tests. CONCLUSIONS: The presented approach is a valuable tool for identifying patients with dementia or MCI and for supporting the clinician in the diagnostic process, by providing an outstanding support decision tool in the diagnostics of neurodegenerative diseases.

Effect of plant development (age and size) on the Mi-1-mediated resistance of tomato to whitefly Bemisia tabaci.

Whitefly, Bemisia tabaci, is one of the most important pests of tomato, Solanum lycopersicum L. The Mi-1 gene mediates tomato resistance to the Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) species of B. tabaci, three species of root-knot nematodes, Meloidogyne spp., and the potato aphid, Macrosiphum euphorbiae. Tomato seedlings bearing the Mi-1 gene are resistant to nematodes soon after germination but resistance to aphids is developmentally regulated; a reliable conclusion about Mi-1 resistance to B. tabaci was not available to date. In the present work, 3-, 5- and 8-week-old plants of the tomato cultivars Motelle and Moneymaker (bearing and lacking the Mi-1 gene, respectively) were simultaneously tested under free-choice (antixenosis) and no-choice (antibiosis) conditions, to assess the real influence of plant age on the Mi-1-mediated resistance to the MED species of B. tabaci. Subsequently, plants of the same age but with different level of development were compared to check whether the plant size can also affect this tomato resistance. Obtained results demonstrated that Mi-1-mediated resistance to B. tabaci is developmentally regulated, as variations in the age of bearing-Mi-1 plants affects most infestation parameters tested. Differences between cultivars with and without the Mi-1 gene were significant for 8- but not for 3-week-old plants. For 5-week-old plants, differences between cultivars were less pronounced than in older plants, expressing an intermediate level of resistance in Motelle. Plant size also influenced whitefly infestation and reproductive activity on the resistant cultivar. However, plant age has more impact than plant size on the Mi-1-mediated resistance of tomato to B. tabaci.

Morphological and molecular characterization of Cladosporium cladosporioides species complex causing pecan tree leaf spot.

The objective of this study was to characterize species of the Cladosporium cladosporioides complex isolated from pecan trees (Carya illinoinensis) with symptoms of leaf spot, based on morphological and molecular approaches. Morphological attributes were assessed using monosporic cultures on potato dextrose agar medium, which were examined for mycelial growth, sporulation, color, and conidia and ramoconidia size. Molecular characterization comprised isolation of DNA and subsequent amplification of the translation elongation factor 1α (TEF-1α) region. Three species of the C. cladosporioides complex were identified: C. cladosporioides, Cladosporium pseudocladosporioides, and Cladosporium subuliforme. Sporulation was the most important characteristic differentiating species of this genus. However, morphological features must be considered together with molecular analysis, as certain characters are indistinguishable between species. TEF-1αcan be effectively used to identify and group isolates belonging to the C. cladosporioides complex. The present study provides an important example of a methodology to ascertain similarity between isolates of this complex causing leaf spot in pecan trees, which should facilitate future pathogenicity studies.

Competitive counterion complexation allows the true host : guest binding constants from a single titration by ionic receptors.

Counterion competitive complexation is a background process currently ignored by using ionic hosts. Consequently, guest binding constants are strongly affected by the design of the titration experiments in such a way that the results are dependent on the guest concentration and on the presence of added salts, usually buffers. In the present manuscript we show that these experimental difficulties can be overcome by just considering the counterion competitive complexation. Moreover a single titration allows us to obtain not only the true binding constants but also the stoichiometry of the complex showing the formation of 1 : 1 : 1 (host : guest : counterion) complexes. The detection of high stoichiometry complexes is not restricted to a single titration experiment but also to a displacement assay where both competitive and competitive-cooperative complexation models are taken into consideration.

The use of genetic markers in the molecular epidemiology of histoplasmosis: a systematic review.

Histoplasmosis is a systemic mycosis caused by Histoplasma capsulatum, a dimorphic fungal pathogen that can infect both humans and animals. This disease has worldwide distribution and affects mainly immunocompromised individuals. In the environment, H. capsulatum grows as mold but undergoes a morphologic transition to the yeast morphotype under special conditions. Molecular techniques are important tools to conduct epidemiologic investigations for fungal detection, identification of infection sources, and determination of different fungal genotypes associated to a particular disease symptom. In this study, we performed a systematic review in the PubMed database to improve the understanding about the molecular epidemiology of histoplasmosis. This search was restricted to English and Spanish articles. We included a combination of specific keywords: molecular typing [OR] genetic diversity [OR] polymorphism [AND] H. capsulatum; molecular epidemiology [AND] histoplasmosis; and molecular epidemiology [AND] Histoplasma. In addition, we used the specific terms: histoplasmosis [AND] outbreaks. Non-English or non-Spanish articles, dead links, and duplicate results were excluded from the review. The results reached show that the main methods used for molecular typing of H. capsulatum were: restriction fragment length polymorphism, random amplified polymorphic DNA, microsatellites polymorphism, sequencing of internal transcribed spacers region, and multilocus sequence typing. Different genetic profiles were identified among H. capsulatum isolates, which can be grouped according to their source, geographical origin, and clinical manifestations.