Building momentum through networks: Bioimaging across the Americas.

In September 2023, the two largest bioimaging networks in the Americas, Latin America Bioimaging (LABI) and BioImaging North America (BINA), came together during a 1-week meeting in Mexico. This meeting provided opportunities for participants to interact closely with decision-makers from imaging core facilities across the Americas. The meeting was held in a hybrid format and attended in-person by imaging scientists from across the Americas, including Canada, the United States, Mexico, Colombia, Peru, Argentina, Chile, Brazil and Uruguay. The aims of the meeting were to discuss progress achieved over the past year, to foster networking and collaborative efforts among members of both communities, to bring together key members of the international imaging community to promote the exchange of experience and expertise, to engage with industry partners, and to establish future directions within each individual network, as well as common goals. This meeting report summarises the discussions exchanged, the achievements shared, and the goals set during the LABIxBINA2023: Bioimaging across the Americas meeting.

Feature-based 3D+t descriptors of hyperactivated human sperm beat patterns.

The flagellar movement of the mammalian sperm plays a crucial role in fertilization. In the female reproductive tract, human spermatozoa undergo a process called capacitation which promotes changes in their motility. Only capacitated spermatozoa may be hyperactivated and only those that transition to hyperactivated motility are capable of fertilizing the egg. Hyperactivated motility is characterized by asymmetric flagellar bends of greater amplitude and lower frequency. Historically, clinical fertilization studies have used two-dimensional analysis to classify sperm motility, despite the inherently three-dimensional (3D) nature of sperm motion. Recent research has described several 3D beating features of sperm flagella. However, the 3D motility pattern of hyperactivated spermatozoa has not yet been characterized. One of the main challenges in classifying these patterns in 3D is the lack of a ground-truth reference, as it can be difficult to visually assess differences in flagellar beat patterns. Additionally, it is worth noting that only a relatively small proportion, approximately 10-20% of sperm incubated under capacitating conditions exhibit hyperactivated motility. In this work, we used a multifocal image acquisition system that can acquire, segment, and track sperm flagella in 3D+t. We developed a feature-based vector that describes the spatio-temporal flagellar sperm motility patterns by an envelope of ellipses. The classification results obtained using our 3D feature-based descriptors can serve as potential label for future work involving deep neural networks. By using the classification results as labels, it will be possible to train a deep neural network to automatically classify spermatozoa based on their 3D flagellar beating patterns. We demonstrated the effectiveness of the descriptors by applying them to a dataset of human sperm cells and showing that they can accurately differentiate between non-hyperactivated and hyperactivated 3D motility patterns of the sperm cells. This work contributes to the understanding of 3D flagellar hyperactive motility patterns and provides a framework for research in the fields of human and animal fertility.

Nanocomposites of Silicon Oxides and Carbon: Its Study as Luminescent Nanomaterials.

In this work, hybrid structures formed by nanostructured layers, which contain materials, such as porous silicon (PSi), carbon nanotubes (CNTs), graphene oxide (GO), and silicon-rich oxide (SRO), were studied. The PSi layers were obtained by electrochemical etching over which CNTs and GO were deposited by spin coating. In addition, SRO layers, in which silicon nanocrystals are embedded, were obtained by hot filament chemical vapor deposition (HFCVD) technique. Photoluminescence (PL) spectra were obtained from the hybrid structures with which a comparative analysis was completed among different PL ones. The SRO layers were used to confine the CNTs and GO. The main purpose of making these hybrid structures is to modulate their PL response and obtain different emission energy regions in the PL response. It was found that the PL spectra of the CNTs/SRO and GO/SRO structures exhibit a shift towards high energies compared to those obtained from the PSi layers; likewise, the PSi/CNTs/SRO and PSi/GO/SRO structures show a similar behavior. To identify the different emission mechanisms originated by PSi, GO, CNTs, and SRO, the PL spectra were deconvolved. It was found that the Psi/CNTs/SRO and Psi/GO/SRO structures exhibit a PL shift in respect to the PSi layers, for this reason, the modulation of the PL emission of the structures makes these hybrid structures promising candidates to be applied in the field of photonic and electroluminescent devices.

Extending resolution within a single imaging frame.

The resolution of fluorescence microscopy images is limited by the physical properties of light. In the last decade, numerous super-resolution microscopy (SRM) approaches have been proposed to deal with such hindrance. Here we present Mean-Shift Super Resolution (MSSR), a new SRM algorithm based on the Mean Shift theory, which extends spatial resolution of single fluorescence images beyond the diffraction limit of light. MSSR works on low and high fluorophore densities, is not limited by the architecture of the optical setup and is applicable to single images as well as temporal series. The theoretical limit of spatial resolution, based on optimized real-world imaging conditions and analysis of temporal image stacks, has been measured to be 40 nm. Furthermore, MSSR has denoising capabilities that outperform other SRM approaches. Along with its wide accessibility, MSSR is a powerful, flexible, and generic tool for multidimensional and live cell imaging applications.

3D+t feature-based descriptor for unsupervised flagellar human sperm beat classification.

Human spermatozoa must swim through the female reproductive tract, where they undergo a series of biochemical and biophysical reactions called capacitation, a necessary step to fertilize the egg. Capacitation promotes changes in the motility pattern. Historically, a two-dimensional analysis has been used to classify sperm motility and clinical fertilization studies. Nevertheless, in a natural environment sperm motility is three-dimensional (3D). Imaging flagella of freely swimming sperm is a difficult task due to their high beating frequency of up to 25 Hz. Very recent studies have described several sperm flagellum 3D beating features (curvature, torsion, asymmetries, etc.). However, up to date, the 3D motility pattern of hyperactivated spermatozoa has not been characterized. The main difficulty in classifying these patterns in 3D is the lack of a ground truth reference since differences in flagellar beat patterns are very difficult to assess visually. Moreover, only around 10-20% of induced to capacitate spermatozoa are truly capacitated, i.e., hyperactivated. We used an image acquisition system that can acquire, segment, and track spermatozoa flagella in 3D+t. In this work, we propose an original three-dimensional feature vector formed by ellipses describing the envelope of the 3D+t spatio-temporal flagellar sperm motility patterns. These features allowed compressing an unlabeled 3D+t dataset to separate hyperactivated cells from others (capacitated from non-capacitated cells) using unsupervised hierarchical clustering. Preliminary results show three main clusters of flagellar motility patterns. The first principal component of these 3D flagella measurements correlated with 2D OpenCASA head determinations as a first approach to validate the unsupervised classification, showing a reasonable correlation coefficient near to 0.7. Clinical relevance- The novelty of this work is defining a 3D+t feature-based descriptor consisting of a set of ellipses enveloping the flagellar motion of human sperm for its unsu-pervised classification. This is a new promising tool to determine the viability of human sperm to fertilize the egg.

Fluorescence fluctuation-based super-resolution microscopy: Basic concepts for an easy start.

Due to the wave nature of light, optical microscopy has a lower-bound lateral resolution limit of approximately half of the wavelength of visible light, that is, within the range of 200 to 350 nm. Fluorescence fluctuation-based super-resolution microscopy (FF-SRM) is a term used to encompass a collection of image analysis techniques that rely on the statistical processing of temporal variations of the fluorescence signal. FF-SRM aims to reduce the uncertainty of the location of fluorophores within an image, often improving spatial resolution by several tens of nanometers. FF-SRM is suitable for live-cell imaging due to its compatibility with most fluorescent probes and relatively simple instrumental and experimental requirements, which are mostly camera-based epifluorescence instruments. Each FF-SRM approach has strengths and weaknesses, which depend directly on the underlying statistical principles through which enhanced spatial resolution is achieved. In this review, the basic concepts and principles behind a range of FF-SRM methods published to date are described. Their operational parameters are explained and guidance for their selection is provided.

Due to light's wave nature, an optical microscope's resolution range is 200 to 350 nanometers. Several techniques enhance resolution; this work encompasses several fluorescence fluctuation super-resolution (FF-SMR) methods capable of achieving nanoscopic scales. FF-SRM is known to be suitable for fixed or live-cell imaging and compatible with most conventional microscope setups found in a laboratory. However, each FF-SRM approach has its strengths and weaknesses, which depend directly on the underlying principles through which enhanced spatial resolution is achieved. Therefore, the basic concepts and principles behind diverse FF-SRM methods are revisited in this review. In addition, their operational parameters are explained, and guidance for their selection is provided for microscopists interested in FF-SRM.

MIS-Like Structures with Silicon-Rich Oxide Films Obtained by HFCVD: Their Response as Photodetectors.

MIS-type structures composed of silicon-rich oxide (SRO), thin films deposited by hot filament chemical vapor deposition (HFCVD), show interesting I-V and I-t properties under white light illumination and a response as photodetectors. From electrical measurements, it was found that at a reverse bias of -4 V, the illumination current increased by up to three orders of magnitude relative to the dark current, which was about 82 nA, while the photogenerated current reached a value of 25 µA. The reported MIS structure with SRO as the dielectric layer exhibited a hopping conduction mechanism, and an ohmic conduction mechanism was found with low voltage. I-t measurements confirmed the increased photogenerated current. Furthermore, the MIS structure, characterized by current-wavelength (I-λ) measurements, exhibited a maximum responsivity value at 254 mA/W, specific detectivity (D*) at 2.21 × 1011 cm Hz1/2 W-1, and a noise equivalent power (NEP) of 49 pW at a wavelength of 535 nm. The structure exhibited good switching behavior, with rise and fall times between 120 and 150 ms, respectively. These rise and decay times explain the generation and recombination of charge carriers and the trapping and release of traps, respectively. These results make MIS-type structures useful as photodetectors in the 420 to 590 nm range.

Retained Copper Intrauterine Device Fragment in Pregnancy: A Case Report.

Copper intrauterine device (IUD) failure and fragmentation are rare, with minimal documentation on their effects in pregnancy. Recommendations from professional organizations highlight the importance of prompt identification and surgical removal, as case reports have noted various acute and chronic intra-abdominal pathologies. However, limited guidance exists around counseling patients who are pregnant with a retained IUD fragment. Here, we present a case of a normal pregnancy with a retained copper IUD fragment, while reviewing existing data on management and counseling.

Folleto complementario de Parasitología Médica para estudiantes de la carrera de Medicina / Supplementary booklet of Medical Parasitology for medicine major students

RESUMEN Fundamento: la asignatura Microbiología y Parasitología Médica aporta las herramientas necesarias para el abordaje de los problemas de salud de la población, en los que intervienen agentes biológicos. Objetivo: diseñar un folleto complementario sobre el tema Parasitología Médica de la asignatura Microbiología y Parasitología Médica para estudiantes de segundo año de la carrera de Medicina de la Facultad de Ciencias Médicas Ernesto Che Guevara de la Serna de Pinar del Río. Métodos: se realizó una investigación educativa, con un universo de 455 estudiantes de segundo año de Medicina durante el curso 2019-2020, en la Facultad de Ciencias Médicas "Ernesto Ché Guevara de la Serna" de Pinar del Río, y 118 profesores que conforman el claustro de este año de la carrera. La muestra quedó conformada por 171 estudiantes y 16 profesores seleccionados de manera intencional. Resultados: se evidenció cierto grado de desactualización sobre los contenidos de Parasitología Médica en la asigantura Microbiología y Parasitología Médica. Se constató la necesidad de estudiantes y profesores de contar con un folleto complementario de Parasitología Médica. Se elaboró un Folleto Complementario de Parasitología Médica para estudiantes de la carrera de Medicina. Conclusiones: el folleto confeccionado fue valorado por los especialistas como útil y pertinente, por la actualización de sus contenidos y tratamiento metodológico.

ABSTRACT Rationale: the subject Medical Microbiology and Parasitology provides the necessary tools for the approach of health problems of the population, in which biological agents are involved. Objective: to design a complementary booklet on the topic Medical Parasitology of the subject Medical Microbiology and Parasitology for second academic-year students of medicine major at Ernesto Che Guevara de la Serna School of Medical Sciences of Pinar del Río. Methods: an educational research was carried out with a target group of 455 students from second academic-year students of medicine major during the course 2019-2020 at Ernesto Che Guevara de la Serna School of Medical Sciences of Pinar del Río and 118 professors comprising the teaching staff of this academic year in medicine major. The sample included 171 students and 16 professors who were intentionally selected. Theoretical, empirical and statistical methods were applied. Results: there was evidence of a certain degree of lack of updating on the contents of Medical Parasitology in the Microbiology and Medical Parasitology course. The need of students and professors to have a complementary booklet on Medical Parasitology was noted. A Complementary Booklet on Medical Parasitology was devised for students of medicine major. Conclusions: the booklet was considered useful and pertinent by the specialists, due to its updated contents and methodological treatment.

Nanoscale organization of rotavirus replication machineries.

Rotavirus genome replication and assembly take place in cytoplasmic electron dense inclusions termed viroplasms (VPs). Previous conventional optical microscopy studies observing the intracellular distribution of rotavirus proteins and their organization in VPs have lacked molecular-scale spatial resolution, due to inherent spatial resolution constraints. In this work we employed super-resolution microscopy to reveal the nanometric-scale organization of VPs formed during rotavirus infection, and quantitatively describe the structural organization of seven viral proteins within and around the VPs. The observed viral components are spatially organized as five concentric layers, in which NSP5 localizes at the center of the VPs, surrounded by a layer of NSP2 and NSP4 proteins, followed by an intermediate zone comprised of the VP1, VP2, VP6. In the outermost zone, we observed a ring of VP4 and finally a layer of VP7. These findings show that rotavirus VPs are highly organized organelles.

Percepción de riesgo sobre VIH/sida en pacientes atendidos por infecciones de trasmisión sexual

Fundamento: a treinta años del comienzo de la infección por el virus de inmunodeficiencia humana en el mundo, la poca percepción de riesgo de la enfermedad se mantiene como un factor determinante en la trasmisión del virus. Objetivo: determinar la percepción de riesgo sobre virus de inmunodeficiencia humana/sida que tienen los pacientes atendidos por infecciones de trasmisión sexual en el Policlínico área Centro de Sancti Spíritus en el año 2011. Metodología: se realizó un estudio descriptivo. La población fue de 116 pacientes, para la recolección de la información se aplicó una encuesta validada por expertos, previo consentimiento de los pacientes. Resultados: predominaron las edades entre 15 y 44 años, el estado civil soltero, el nivel de escolaridad universitario y el técnico medio terminado respectivamente, se observó que la mayoría fueron trabajadores. No existe percepción del riesgo de enfermar en los encuestados, asimismo no identifican objetivamente los motivos que aumentan la posibilidad de enfermar, sino que lo ven de forma muy subjetiva, unido al no uso del condón como medida preventiva para no enfermar en un número considerable de pacientes. Conclusiones: el uso del condón es insuficiente y aún tienen baja o ninguna percepción de riesgo a la infección por VIH(AU)

Comportamiento de algunos factores de riesgo en un grupo de hipertensos esenciales / The behavior of several risk factor in a group of essential hypertensive patients

Estudiamos 52 pacientes hipertensos esenciales comprendidos entre 23 y 59 años de ambos sexos, sin considerar diferencias raciales pertenecientes al Policlínico de la Universidad Central de Las Villas en el período de septiembre-noviembre del 2003, con el propósito de valorar el comportamiento de algunos factores de riesgo cardiovascular. Empleamos un modelo de encuesta para la recolección de datos personales, resultados de laboratorio y prueba de peso sostenido

Comportamiento de algunos factores de riesgo en un grupo de hipertensión esenciales / The behavior of several risk factor in a group of essential hypertensive patients

estudiamos 52 pacientes hipertensos sesnciales comprendidos entre 23 y 59 años de ambos sexos, sin considerar diferencias raciales pertenecientes al Policlínico de la Universidad Centrla de Las Villas en el período de septiembre-noviembre del 2003, con el propósito de valorar el comportamiento de algunos factores de riesgo cardiovascular. Empleamos un modelo de encuesta para la recolección de datos personales, resultados de laboratorio y prueba de peso sostenido(AU)

Respuesta cadiovascular a la sobrecarga salina de un grupo de hipertensos ligeros / Cardiovascular response to saline overload of a group of mild hypertensive patients

Se realizó un estudio del comportamiento de la presión arterial en humanos, para lo cual fueron valorados 68 individuos en condiciones de reposo y durante la realización de pruebas de hiperreactividad vascular, antes de la administración oral de una sobrecarga salina y después de la misma. Nos propusimos comparar el comportamiento de algunas variables hemodinámicas y del indicador PD 20-40, durante las pruebas ergométricas y de respiración en circuito cerrado con concentraciones crecientes de C02, en las condiciones experimentales citadas. La muestra se dividió en tres grupos: normotensos, hipertensos sal sensibles e hipertensos sal resistentes. Se obtuvieron valores superiores de las variables hemodinámicas estudiadas en los hipertensos sal resistentes antes de la sal; después de ésta las variables analizadas fueron superiores en los sal sensibles y disminuyeron en los resistentes, por lo que se obtuvieron diferencias significativas(AU)