Usefulness of thoracic ultrasound in the assessment of removal of indwelling pleural catheter in patients with malignant pleural effusion.

INTRODUCTION: There are no defined criteria for deciding to remove a non-functioning indwelling pleural catheter (IPC) when lung re-expansion on chest X-ray is incomplete. Chest computed tomography (chest CT) is usually used. The objective of this work is to validate the usefulness of chest ultrasound performed by a pulmonologist and by a radiologist compared to chest CT. PATIENTS AND METHODS: Prospective, descriptive, multidisciplinary and multicenter study including patients with malignant pleural effusion and non-functioning IPC without lung reexpansion. Decisions made on the basis of chest ultrasound performed by a pulmonologist, and performed by a radiologist, were compared with chest CT as the gold standard. RESULTS: 18 patients were analyzed, all of them underwent ultrasound by a pulmonologist and chest CT and in 11 of them also ultrasound by a radiologist. The ultrasound performed by the pulmonologist presents a sensitivity of 60%, specificity of 100%, PPV 100% and NPV 66% in the decision of the correct removal of the IPC. The concordance of both ultrasounds (pulmonologist and radiologist) was 100%, with a kappa index of 1. The 4 discordant cases were those in which the IPC was not located on the ultrasound. CONCLUSIONS: Thoracic ultrasound performed by an expert pulmonologist is a valid and simple tool to determine spontaneous pleurodesis and remove a non-functioning IPC, which would make it possible to avoid chest CT in those cases in which lung reexpansion is observed with ultrasonography.

Microfluidic-based skin-on-chip systems for safety assessment of nanomaterials.

The skin is the body's largest organ, continuously exposed to and affected by natural and anthropogenic nanomaterials (materials with external and internal dimensions in the nanoscale range). This broad spectrum of insults gives rise to irreversible health effects (from skin corrosion to cancer). Organ-on-chip systems can recapitulate skin physiology with high fidelity and potentially revolutionize the safety assessment of nanomaterials. Here, we review current advances in skin-on-chip models and their potential to elucidate biological mechanisms. Further, strategies are discussed to recapitulate skin physiology on-chip, improving control over nanomaterials exposure and transport across cells. Finally, we highlight future opportunities and challenges from design and fabrication to acceptance by regulatory bodies and industry.

Evolutionary dynamics of autopolyploids in natural populations: the case of Turnera sidoides complex / Dinámica evolutiva de autopoliploides en poblaciones naturales: el caso del complejo Turnera sidoides

ABSTRACT Turnera sidoides (x=7) is one of the few well-studied South American autopolyploid complexes. Since polyploidy has played a prominent role within this complex, ongoing studies in T. sidoides focus on understanding the mechanisms involved in the origin and the establishment of polyploids using integrative approaches. This paper synthesises the results of more than 20 years of research on this topic. Cytogenetics analysis provided evidences for the production of unreduced male and female gametes, supporting the hypothesis of bilateral sexual polyploidization as the mechanism of origin of polyploids in T. sidoides. The finding of viable triploids suggested that unilateral sexual polyploidization could also be an important mechanism for the origin of tetraploids in T. sidoides. The occurrence of plants continuously forming many unreduced gametes would play a key role in the establishment of neopolyploids in natural populations. Also, the higher number of propagules that tetraploids contribute to subsequent generations, the ability to multiply asexually by rhizomes, and the occurrence of occasional cases of self-compatibility and successful illegitimate crosses in polyploids increase the likelihood that a low frequency of neopolyploids can be maintained in natural populations of T. sidoides. In addition, integration of cytogeographic and genetic divergence data together with past niche modelling provided further insights supporting the hypothesis that historical climatic and geomorphological events provided favourable conditions for the establishment of autopolyploids, with the wider distribution of tetraploids of T. sidoides being the result of their range expansion.

RESUMEN Turnera sidoides (x=7) es uno de los pocos complejos autopoliploides sudamericanos bien estudiados. Como la poliploidía ha tenido un papel destacado en el complejo, los estudios en curso en T. sidoides se centraron en la comprensión de los mecanismos implicados en el origen y el establecimiento de los poliploides mediante diferentes enfoques. En este trabajo se sintetizan los resultados de más de 20 años de investigación sobre este tema. El análisis citogenético proporcionó evidencias de la producción de gametos masculinos y femeninos no reducidos, sustentando la hipótesis de la poliploidización sexual bilateral como mecanismo de origen de los poliploides en T. sidoides. Sin embargo, el hallazgo de triploides fértiles sugirió que la poliploidización sexual unilateral también sería un mecanismo importante de origen de tetraploides en T. sidoides. La ocurrencia de plantas que forman continuamente gametos no reducidos desempeñaría un papel clave en el establecimiento de neopoliploides. Además, el mayor número de propágulos que los tetraploides aportan a las siguientes generaciones, la capacidad de multiplicación asexual por rizomas y los casos ocasionales de autocompatibilidad y cruzamientos ilegítimos exitosos aumentarían la probabilidad de que se mantenga una baja frecuencia de neopoliploides en las poblaciones naturales de T. sidoides. Asimismo, la integración de datos citogeográficos y de divergencia genética junto con el modelado de nicho en el pasado aportó información que sustenta la hipótesis de que los eventos climáticos y geomorfológicos históricos proporcionaron las condiciones favorables para el establecimiento y expansión de los tetraploides de T. sidoides.

[Computer-assisted total bilateral knee arthroplasty in one surgical time]. / Artroplastía total de rodilla bilateral en un tiempo quirúrgico asistida por computadora.

INTRODUCTION: Total navigated knee replacement uses a computer-guided system, which provides immediate information on pre-cut trans-operative conditions of the knee, in relation to pelvic limb alignment. MATERIAL AND METHODS: Observational, descriptive study conducted from March 2003 to February 2019. Total bilateral knee replacement was performed at the same time surgically by a surgeon, evaluating function and pain on the WOMAC, EVA, and range of motion scores of both knees. Two groups of patients were studied: the first represents presurgical and the second post-surgical. Student's t-test and 2 were applied for statistical analysis. RESULTS: 31 patients (62 prostheses), 83.9% of the female sex and 16.1% male, average age 67.32 years, average follow-up 6.55 years (± 3.8) were studied. It was identified that 100% of the patients in both knees have a deviation between 0o and 2o measured in the mechanical axis. The WOMAC scale showed an average of 22.71 ± 3.34 presurgical and 4.16 ± 1.84) post-surgical, with statistically significant differences. The average analog visual scale was 9.06 ± 0.814 presurgical and 2.35 ± 1.427 post-surgical. CONCLUSIONS: This technique is reliable, safe and satisfactory. Excellent clinical and radiographic results were evident regarding the positioning of prosthetic components.

INTRODUCCIÓN: La artroplastía total de rodilla navegada utiliza un sistema guiado por computadora que proporciona información inmediata de condiciones transoperatorias precorte de la rodilla, con relación a la alineación del miembro pélvico. MATERIAL Y MÉTODOS: Estudio observacional, descriptivo, efectuado de Marzo de 2003 a Febrero de 2019. Se realizó artroplastía total de rodilla bilateral navegada en un mismo tiempo quirúrgico por un cirujano, evaluando función y dolor según las escalas WOMAC, EVA y arcos de movilidad de ambas rodillas. Se estudiaron dos grupos de pacientes: el primero representa prequirúrgicos y el segundo postquirúrgicos. Se aplicó prueba t de Student y 2 para el análisis estadístico. RESULTADOS: Se estudiaron 31 pacientes (62 prótesis), 83.9% del sexo femenino y 16.1% del masculino, edad media 67.32 años, media de seguimiento 6.55 años (± 3.8). Se identificó que 100% de los pacientes intervenidos en ambas rodillas tienen una desviación entre 0o y 2o medida en el eje mecánico. La escala WOMAC mostró una media de 22.71 ± 3.34 prequirúrgica y 4.16 ± 1.84 postquirúrgica, con diferencias estadísticamente significativas. La escala visual análoga media fue de 9.06 ± 0.814 prequirúrgico y 2.35 ± 1.427 postquirúrgico. CONCLUSIONES: Esta técnica es confiable, segura y satisfactoria. Se evidenciaron excelentes resultados clínicos y radiográficos respecto al posicionamiento de los componentes protésicos.

Active Versus Passive Flow Control in UVC FILTERs for COVID-19 Containment.

Ultraviolet radiation as a germicide is widely used in the health field and even in domestic hygiene. Here, we propose an improvement in low-cost portable units of filtration for indoor air, which is based on ultraviolet radiation. In the current technology, to carry out an air filtration with a suspension of aerosols in which there is a likely concentration of pathogens, whether viral, bacterial or molds, the air is forced to pass as close as possible to the ionizing radiation source (near field). Since the optical mass is very small, the desired effect can be achieved in a considerably short time, deactivating the infective potential of these biological agents. The proposal of this work is the regulation of the flow or speed control of passage through these filters by passive elements instead of by electronic control systems. For this, two devices have been designed, simulated, and built, obtaining similar net pathogen inactivation rates under different flow rates. The passive flow control device has demonstrated higher performance in terms of flow rate and lower cost of production since they do not require electronics and are produced with fewer diodes. This passive device has also shown a lower projection of maintenance cost, lower energy consumption rate (higher efficiency), and longer projection of useful life.

Diseño y validación de material didáctico para una intervención educativa de enfermería en cuidadores primarios / Design and validation of didactic materials for a nursing educational intervention to primary caregivers / Desenho e validação de material didático para uma intervenção educativa de enfermagem em cuidadores primários

Resumen Introducción: El cuidador es una persona que en sí misma requiere cuidado, existe poca evidencia sobre la validación de material dirigido a cuidadores primarios de adultos en el domicilio. Objetivo: Diseñar y validar el material didáctico de apoyo en una propuesta de intervención educativa de enfermería para mejorar el autocuidado de cuidadores primarios de personas con enfermedades crónicas no transmisibles. Material y Métodos: Investigación metodológica para validación de diez carteles. Evaluación por cuatro expertos y diez cuidadores primarios. La investigación se desarrolló en cuatro fases: a) valoración de las necesidades en salud y determinación de los contenidos, b) elaboración de material didáctico, c) jueceo y validación técnica, d) validación con población. Se evaluaron los aspectos de atracción, comprensión, involucramiento y aceptación con un cuestionario dicotómico de ocho preguntas por cartel. Se calculó el coeficiente V de Aiken como indicador de aprobación. Se tomó el valor de 0.7 y superior como punto para la validación. Resultados: En la primera ronda de evaluación por los expertos se modificaron tres carteles por su bajo coeficiente de comprensión-atracción y se reelaboró un cartel. En la segunda versión de los carteles se alcanzaron coeficientes superiores a 0.81. Sin embargo, los cuidadores puntuaron dos carteles con valores inferiores al estándar, por lo que luego de tomar su opinión al respecto se modificaron aspectos de diseño. Discusión: Las recomendaciones de los expertos en el área y particularmente los intereses de los cuidadores primarios fueron la base para mejorar el diseño del material didáctico. Conclusiones: Tras ajustar elementos de la atracción y comprensión de los carteles se concluyó que el Material Didáctico (MD) es adecuado para su implementación en una Intervención Educativa (IE) dirigida a mejorar el autocuidado de cuidadores primarios.

Abstract Introduction: Caregivers are persons who themselves also need care, and there is few evidence regarding the validation of educational materials for caregivers of adult home care. Objective: To design and validate supporting didactic materials for a nursing educational intervention proposal in order to improve self-care among primary caregivers attending patients with non-transmissible chronic illnesses. Materials and Methods: This is a validating research study using 10 educational materials which were assessed by 4 field experts and 10 primary caregivers. The research study was developed in four stages: a) assessment of the health needs and determination of the contents for the education materials, b) elaboration of the education materials, c) technical validation, d) assessment on the use in a population. Features of attractiveness, comprehension, involvement, and acceptance were estimated using a dichotomous questionnaire of 8 questions for each educational material. The Aiken V coefficient of approval was calculated. Values greater than 0.7 were considered as valid results. Results: In the first round of assessment by the experts, three educational materials were modified due to their low coefficient of comprehension-attractiveness and one education material was redesigned. The subsequent version of the education materials showed coefficients higher than 0.81, however, caregivers gave two materials scores below the standard, and these materials were further redesigned. Discussion: The recommendations from the experts in the field, along with the interests of the primary caregivers, were the base to improve the design of the didactic materials. Conclusions: After adjusting elements related to the attractiveness and comprehension of the didactic materials, it was concluded that the redesigned materials were adequate for an educational intervention aimed at improving self-care among primary caregivers.

Resumo Introdução: O cuidador é uma pessoa que em si mesmo requer de cuidado, há pouca evidência sobre a validação de material dirigido aos cuidadores primários de adultos no domicílio. Objetivo: Desenhar e validar o material didático de apoio em uma proposta de intervenção educativa de enfermagem para melhorar o autocuidado de cuidadores primários de pessoas com doenças crônicas não transmissíveis. Material e Métodos: Pesquisa metodológica para validação de dez pôsteres. Avaliação por quatro especialistas e dez cuidadores primários. A pesquisa desenvolveu-se em quatro fases: a) avaliação das necessidades de saúde e determinação dos conteúdos, b) elaboração do material didático, c) julgamento e validação técnica, d) validação com população. Avaliaram-se os aspectos de atração, compreensão, envolvimento e aceitação com um questionário dicotômico de oito perguntas por pôster. Foi calculado o coeficiente V de Aiken como indicador de aprovação. Tomou-se o valor de 0.7 e superior como ponto para a validação. Resultados: Na primeira rodada de avaliação dos especialistas modificaram-se três pôsteres por seu baixo coeficiente de compreensão-atração e foi reelaborado um pôster. Na segunda versão dos pôsteres foram alcançados coeficientes superiores a 0.81. Porém, os cuidadores pontuaram dois pôsteres com valores inferiores ao padrão, portanto, após se manifestarem sobre o assunto modificaram-se aspectos de desenho. Discussão: As recomendações dos especialistas da área e particularmente, os interesses dos cuidadores primários foram a base para melhorar o desenho do material didático. Conclusões: Após ajustar elementos da atração e compreensão dos pôsteres foi concluído que o MD é adequado para sua implementação em uma IE dirigida a melhorar o autocuidado de cuidadores primários.

Epigenetic regulation of folate receptor-α (FOLR1) in human placenta of preterm newborns.

INTRODUCTION: Folates are essential nutrients for fetal development and pregnancy outcomes; they are transported to the fetus during gestation through specific folate transporters located in the placenta. In preterm newborns, we previously showed a lower placental mRNA expression of FOLR1 along with higher folate and lower vitamin B12 cord blood levels. Thereby we aimed to explore FOLR1 methylation in placentas of preterm newborns and hypothesized an increased FOLR1 methylation associated with cord blood folates and vitamin B12 concentrations. METHODS: FOLR1 methylation and mRNA were determined by methylation sensitive - high resolution melting (MS-HRM) and by real-time PCR respectively, in two placental sides of placental tissues: maternal (basal, BP) and fetal plates (chorionic, CP) of moderate preterm infants (32-36 gestational age) and term birth (37-41 gestational weeks). Folates and vitamin B12 were determined by electrochemiluminescence in umbilical cord blood samples from term and preterm newborns. RESULTS: We found that in preterm newborns, FOLR1 mRNA was lower in both plates of placenta compared with term newborns (p < 0,05) and was negatively associated with methylation of FOLR1 in CP. Preterm newborns presented higher folate and lower vitB12 concentrations in cord blood which correlated with increased placental FOLR1 methylation. DISCUSSION: In preterm newborns, placental FOLR1 expression is regulated by epigenetic mechanisms and presumably by maternal concentrations of folate and vitamin B12.

Three-dimensional skeletal changes after early proportional condylectomy for condylar hyperplasia.

The purpose of this study was to evaluate volumetric and dentoskeletal changes in 21 patients with active unilateral condylar hyperplasia (AUCH) after proportional condylectomy. A split-mouth design was used: control group healthy joints (HS, healthy side) and test group affected joints (AS, affected side) (21 per group). Cone beam tomography scans were obtained at T0 (preoperative), T1 (10days after the intervention), and T2 (approximately 12 months post-surgery). The condylar unit volume (CUV), articular cavity volume (ACV), and dentoalveolar units (DAUs) were measured. CUV showed a difference of 1.12cm3 between T0 and T1, increasing 0.4cm3 between T1 and T2 on AS. There was no difference between T0 and T2 on HS. ACV increased 0.65cm3 between T0 and T1 on AS, after which it decreased by 0.36cm3 at T2 (0.30cm3 larger than the initial articular cavity at T0). ACV showed no post-surgery differences on HS. Midline DAU showed extrusion of 0.20mm for maxilla and 0.52mm for mandible, while in the lateral area, maxilla was extruded by 0.3mm on HS and was intruded 0.12mm on AS. For the mandible, both sides showed extrusion (0.4-0.6mm). In the distal to canine and molar areas, intrusion of 0.2mm and 0.9mm, respectively, was observed on AS; there was extrusion of 0.6mm distal to the canine on HS. At the mandibular level, AS distal to the canine showed extrusion of 1mm, while intrusion of 0.2mm was observed in the molars. For HS, only extrusion at the molar level (0.2mm) was observed. In conclusion, after proportional condylectomy, a neocondyle forms within 12 months to equal the healthy contralateral side. The articular cavity, which is reduced in the initial stage, increases in size after surgery and the volume gradually approaches that of the healthy side. Dentoalveolar changes occur at the anterior and posterior levels, causing intrusion and extrusion of the interdental crests. An early proportional condylectomy as the sole surgical treatment for patients with AUCH allows normalization of the maxillomandibular relationship.

Early outcome of a 31-gene expression profile test in 86 AJCC stage IB-II melanoma patients. A prospective multicentre cohort study.

BACKGROUND: The clinical and pathological features of primary melanoma are not sufficiently sensitive to accurately predict which patients are at a greater risk of relapse. Recently, a 31-gene expression profile (DecisionDx-Melanoma) test has shown promising results. OBJECTIVES: To evaluate the early prognostic performance of a genetic signature in a multicentre prospectively evaluated cohort. METHODS: Inclusion of patients with AJCC stages IB and II conducted between April 2015 and December 2016. All patients were followed up prospectively to assess their risk of relapse. Prognostic performance of this test was evaluated individually and later combined with the AJCC staging system. Prognostic accuracy of disease-free survival was determined using Kaplan-Meier curves and Cox regression analysis. Results of the gene expression profile test were designated as Class 1 (low risk) and Class 2 (high risk). RESULTS: Median follow-up time was 26 months (IQR 22-30). The gene expression profile test was performed with 86 patients; seven had developed metastasis (8.1%) and all of them were in the Class 2 group, representing 21.2% of this group. Gene expression profile was an independent prognostic factor for relapse as indicated by multivariate Cox regression analysis, adjusted for AJCC stages and age. CONCLUSIONS: This prospective multicentre cohort study, performed in a Spanish Caucasian cohort, shows that this 31-gene expression profile test could correctly identify patients at early AJCC stages who are at greater risk of relapse. We believe that gene expression profile in combination with the AJCC staging system could well improve the detection of patients who need intensive surveillance and optimize follow-up strategies.

Using radio astronomical receivers for molecular spectroscopic characterization in astrochemical laboratory simulations: A proof of concept.

We present a proof of concept on the coupling of radio astronomical receivers and spectrometers with chemical reactors and the performances of the resulting setup for spectroscopy and chemical simulations in laboratory astrophysics. Several experiments including cold plasma generation and UV photochemistry were performed in a 40 cm long gas cell placed in the beam path of the Aries 40 m radio telescope receivers operating in the 41-49 GHz frequency range interfaced with fast Fourier transform spectrometers providing 2 GHz bandwidth and 38 kHz resolution. The impedance matching of the cell windows has been studied using different materials. The choice of the material and its thickness was critical to obtain a sensitivity identical to that of standard radio astronomical observations. Spectroscopic signals arising from very low partial pressures of CH3OH, CH3CH2OH, HCOOH, OCS, CS, SO2 (<10-3 mbar) were detected in a few seconds. Fast data acquisition was achieved allowing for kinetic measurements in fragmentation experiments using electron impact or UV irradiation. Time evolution of chemical reactions involving OCS, O2 and CS2 was also observed demonstrating that reactive species, such as CS, can be maintained with high abundance in the gas phase during these experiments.

Unilateral sagittal split ramus osteotomy: an alternative for some cases of asymmetric mandibular prognathism.

The objective of this study was to propose a treatment protocol for patients with lateral prognathism based on the unilateral sagittal split ramus osteotomy (USSRO). This was a prospective study involving 31 patients with lateral prognathism, who required a bilateral sagittal split ramus osteotomy (BSSRO). Two groups were formed using the proposed protocol, with specific inclusion criteria for each group: BSSRO (n=17) and USSRO (n=14). Occlusal parameters (dental midline deviation, overbite, and overjet) were measured preoperatively (T0), at model surgery (T1), 1 month postoperative (T2), and 1year after surgery (T3) and compared. P-values of <0.05 were considered significant. No significant difference was found between the USSRO and BSSRO groups for all occlusal parameters (T0, T1, T2, and T3). In both groups, there was a significant difference between T0 and T1 and no significant difference between T1 and T2 or T1 and T3 in all of the occlusal parameters; the exception was overbite between T1 and T2 in the BSSRO group, which showed a significant difference. No patient in either group showed signs or symptoms of temporomandibular joint dysfunction at T0 or T3. USSRO was found to be a stable alternative in patients with asymmetric mandibular prognathism. At the same time, it reduced the operating time and morbidity when compared to BSSRO.

Prevalence of Barrett's esophagus: An observational study from a gastroenterology clinic. / Prevalencia de esófago de Barrett: estudio observacional en una clínica de gastroenterología.

INTRODUCTION AND AIMS: Barrett's esophagus is a condition that predisposes to esophageal adenocarcinoma. Our aim was to establish the prevalence of Barrett's esophagus at our center, as well as determine its associated factors. MATERIALS AND METHODS: We retrospectively assessed the endoscopic reports of 500 outpatients seen at our Gastroenterology Service from November 2014 to April 2016. We determined the prevalence of Barrett's esophagus and analyzed the demographic, clinical, and endoscopic findings associated with that pathology. RESULTS: The prevalence of Barrett's esophagus was 1.8%. The mean age of the patients with Barrett's esophagus was 58.7 years (range: 45-70) and there was a predominance of men (66%). In the subgroup of patients with symptoms of gastroesophageal reflux (n=125), Barrett's esophagus prevalence was 7.2%. In the multivariate analysis, the factors that were independently associated with Barrett's esophagus were gastroesophageal reflux (P=.005) and hiatal hernia (P=.006). CONCLUSIONS: The overall prevalence of Barrett's esophagus was 1.8% in our population, with a prevalence of 7.2% in patients that had symptoms of gastroesophageal reflux.

Impact of Histological Factors of Hepatocellular Carcinoma on the Outcome of Liver Transplantation.

BACKGROUND: The aim of this study was to identify predictors of overall survival (OS), disease-free survival (DFS), and recurrence in a cohort of 151 patients with hepatocellular carcinoma (HCC) and cirrhosis who were treated by liver transplantation (LT). PATIENTS AND METHODS: A retrospective database of patients undergoing LT for radiologically diagnosed HCC at "12 de Octubre" Hospital, Madrid during 1986-2006 was analyzed. RESULTS: The median follow-up was 67.44 months (SD = 55.7 months). Overall 1-, 3-, 5-, and 10-year survival was 87.5%, 73.7%, 64.1% and 43.4%, respectively. The 5-year OS of patients beyond the Milan criteria was 47.14%, whereas that of patients within the Milan criteria was 70.13% (P = .011). The 5-year OS of patients beyond the Milan criteria and with microvascular invasion (MVI) was 27.27%, whereas that of patients beyond the Milan criteria and without MVI criteria was 57.89% (P = .003). Multivariate analysis of prognostic factors revealed MVI and G3 to be independent and statistically significant factors affecting OS (P < .0001 and P = .045, respectively), DFS (P < .0001 and P = .004, respectively), and recurrence (P = .0002 and P = .028, respectively). Multivariate analysis of prognostic factors also revealed preoperative fine-needle aspiration (FNA) to be an independent negative statistically significant factor affecting recurrence (P = .0022). Multivariate analysis of predictive MVI factors revealed preoperative α-fetoprotein (AFP) levels >200 ng/mL to be an independent positive and statistically significant predictor of MVI (P = .0004). CONCLUSION: MVI and G3 are independent negative factors affecting OS, DFS, and recurrence. The presence of MVI or AFP levels >200 ng/mL represent a contraindication for LT, as long as the patient is beyond the Milan criteria.

Evidence of the occurrence of structural chromosome changes at the initial diploid diversification of the autopolyploid Turnera sidoides L. (Passifloraceae) complex.

Turnera sidoides is an autopolyploid complex of obligate outcrossing perennial herbs. It includes five subspecies and five morphotypes in which diploid to octoploid cytotypes were found. Based on phenetic analyses of the complex and karyotype data of polyploid cytotypes, it has been hypothesized that morphological and chromosome differentiation of T. sidoides occurred at the diploid level. To test this hypothesis, we present the first detailed chromosome analysis of diploid populations of three subspecies and four morphotypes. CMA(+)/DAPI(-) bands were restricted to secondary constrictions (except in the andino morphotype) and varied in number and position among taxa. By contrast, DAPI staining was uniform in all the materials investigated. The number and position of 45S rDNA loci were coincident with the CMA(+)/DAPI(-) bands associated with secondary constrictions. Only one pair of 5S rDNA loci was detected in all the taxa (except in subsp. holosericea), but its position was variable. The identified chromosome markers varied among the three subspecies analyzed, but they were more conserved among the morphotypes of subsp. pinnatifida. Cluster analysis of these chromosome markers supports the current taxonomic arrangement of diploids and demonstrates that structural chromosome changes would have led or accompanied the initial differentiation of T. sidoides at the diploid level.