Enucleation of insulinoma using laparoscopic distal pancreatectomy with a focus on vascular and splenic preservation: a case report.

Insulinomas represent <10% of pancreatic tumors. It is a functional neuroendocrine tumor that can cause recurrent and severe episodes of loss of consciousness due to hypoglycemia. Surgical removal is the only curative treatment. The selection of the optimal surgical technique must be individualized for each patient. Currently, there are emerging innovations in less invasive techniques that reduce morbidity. We present the case of a 23-year-old woman who underwent enucleation of an insulinoma localized at the tip of the pancreatic tail after laparoscopic surgery, with a focus on vascular and splenic preservation. The tumor was safely identified during surgery and enucleated without injury to the spleen and adjacent vascular structures or postoperative complications.

High precision orientation mapping from 4D-STEM precession electron diffraction data through quantitative analysis of diffracted intensities.

The association of scanning transmission electron microscopy (STEM) and detection of a diffraction pattern at each probe position (so-called 4D-STEM) represents one of the most promising approaches to analyze structural properties of materials with nanometric resolution and low irradiation levels. This is widely used for texture analysis of materials using automated crystal orientation mapping (ACOM). Herein, we perform orientation mapping in InP nanowires exploiting precession electron diffraction (PED) patterns acquired by an axial CMOS camera. Crystal orientation is determined at each probe position by the quantitative analysis of diffracted intensities minimizing a residue comparing experiments and simulations in analogy to x-ray structural refinement. Our simulations are based on the two-beam dynamical diffraction approximation and yield a high angular precision (∼0.03°), much lower than the traditional ACOM based on pattern matching algorithms (∼1°). We anticipate that simultaneous exploration of both spot positions and high precision crystal misorientation will allow the exploration of the whole potentiality provided by PED-based 4D-STEM for the characterization of deformation fields in nanomaterials.

A novel scale based on biomarkers associated with COVID-19 severity can predict the need for hospitalization and intensive care, as well as enhanced probabilities for mortality.

Prognostic scales may help to optimize the use of hospital resources, which may be of prime interest in the context of a fast spreading pandemics. Nonetheless, such tools are underdeveloped in the context of COVID-19. In the present article we asked whether accurate prognostic scales could be developed to optimize the use of hospital resources. We retrospectively studied 467 files of hospitalized patients after COVID-19. The odds ratios for 16 different biomarkers were calculated, those that were significantly associated were screened by a Pearson's correlation, and such index was used to establish the mathematical function for each marker. The scales to predict the need for hospitalization, intensive-care requirement and mortality had enhanced sensitivities (0.91 CI 0.87-0.94; 0.96 CI 0.94-0.98; 0.96 CI 0.94-0.98; all with p < 0.0001) and specificities (0.74 CI 0.62-0.83; 0.92 CI 0.87-0.96 and 0.91 CI 0.86-0.94; all with p < 0.0001). Interestingly, when a different population was assayed, these parameters did not change considerably. These results show a novel approach to establish the mathematical function of a marker in the development of highly sensitive prognostic tools, which in this case, may aid in the optimization of hospital resources. An online version of the three algorithms can be found at: http://benepachuca.no-ip.org/covid/index.php.

In vitro propagation of a cuban Arbuscular Mycorrhizal Fungal strain and factible bacteria's association / Propagación in vitro de una cepa cubana de Hongos Micorrízicos Arbusculares y su factible asociación a bacterias

ABSTRACT In vitro root cultivation techniques based on modified root systems are often used in studies on Arbuscular Mycorrhizal Fungi (AMF). It is a simplified but powerful tool to investigate AMF root colonization and development of the extraradical mycelium. The aim of this study was to establish and characterize the in vitro culture of a Cuban strain of Rhizophagus irregularis (INCAM 11) by using transformed chicory roots. For that, superficially disinfected propagules of R. irregularis were co-culture with the hairy transformed chicory roots on Modified Strullu and Romand (MSR) medium during five months. Spore germination was observed 3-5 days after surface disinfection. The first contact between AMF hyphae and roots occurred 1 - 3 days after germination and a significant production of extensive extraradical mycelium was observed. New spore formation started within 21 - 25 days. After 5 months, 2000 spores could be observed per plate which were able to germinate, colonize, establish and reproduce again spores when associated to young transformed roots of chicory. The most frequent associated microorganism to the in vitro culture of INCAM 11 was isolated and identified as Paenibacillus sp.

RESUMEN Las técnicas de cultivo de raíces in vitro basadas en sistemas de raíces modificadas se utilizan a menudo en los estudios sobre hongos micorrízicos arbusculares (HMA). Es una herramienta simplificada pero poderosa para investigar la colonización de las raíces de los HMA y el desarrollo del micelio extrarradical. El objetivo de este estudio fue establecer y caracterizar el cultivo in vitro de una cepa cubana de Rhizophagus irregularis (INCAM 11) utilizando raíces transformadas de achicoria. Para ello, propágulos de R. irregularis desinfectados superficialmente fueron co-cultivados con las raíces transformadas de achicoria en medio Strullu y Romand modificado (SRM) durante cinco meses. La germinación de las esporas se observó 3-5 días después de la desinfección superficial. El primer contacto entre las hifas y las raíces se produjo entre 1 y 3 días después de la germinación y se observó una producción significativa de micelio extrarradical. La formación de nuevas esporas comenzó entre 21 - 25 días. Después de 5 meses, se pudieron observar 2000 esporas por placa que fueron capaces de germinar, colonizar, establecer y reproducir nuevas esporas cuando se asociaron a raíces jóvenes transformadas de achicoria. El microorganismo asociado frecuentemente al cultivo in vitro de INCAM 11 fue aislado e identificado como Paenibacillus sp.

Comparative Study on the Quality of Microcrystalline and Epitaxial Silicon Films Produced by PECVD Using Identical SiF4 Based Process Conditions.

Hydrogenated microcrystalline silicon (µc-Si:H) and epitaxial silicon (epi-Si) films have been produced from SiF4, H2 and Ar mixtures by plasma enhanced chemical vapor deposition (PECVD) at 200 °C. Here, both films were produced using identical deposition conditions, to determine if the conditions for producing µc-Si with the largest crystalline fraction (XC), will also result in epi-Si films that encompass the best quality and largest crystalline silicon (c-Si) fraction. Both characteristics are of importance for the development of thin film transistors (TFTs), thin film solar cells and novel 3D devices since epi-Si films can be grown or etched in a selective manner. Therefore, we have distinguished that the H2/SiF4 ratio affects the XC of µc-Si, the c-Si fraction in epi-Si films, and the structure of the epi-Si/c-Si interface. Raman and UV-Vis ellipsometry were used to evaluate the crystalline volume fraction (Xc) and composition of the deposited layers, while the structure of the films were inspected by high resolution transmission electron microscopy (HRTEM). Notably, the conditions for producing µc-Si with the largest XC are different in comparison to the fabrication conditions of epi-Si films with the best quality and largest c-Si fraction.

Tocilizumab reduces COVID-19 mortality and pathology in a dose and timing-dependent fashion: a multi-centric study.

Life-threatening COVID-19 is associated with strong inflammation, where an IL-6-driven cytokine storm appears to be a cornerstone for enhanced pathology. Nonetheless, the specific inhibition of such pathway has shown mixed outcomes. This could be due to variations in the dose of tocilizumab used, the stage in which the drug is administered or the severity of disease presentation. Thus, we performed a retrospective multicentric study in 140 patients with moderate to critical COVID-19, 79 of which received tocilizumab in variable standard doses (< 400 mg, 400-800 mg or > 800 mg), either at the viral (1-7 days post-symptom onset), early inflammatory (8-15) or late inflammatory (16 or more) stages, and compared it with standard treated patients. Mortality, reduced respiratory support requirements and pathology markers were measured. Tocilizumab significantly reduced the respiratory support requirements (OR 2.71, CI 1.37-4.85 at 95%) and inflammatory markers (OR 4.82, CI 1.4-15.8) of all patients, but mortality was only reduced (4.1% vs 25.7%, p = 0.03) when the drug was administered at the early inflammatory stage and in doses ranging 400-800 mg in severely-ill patients. Despite the apparent inability of Tocilizumab to prevent the progression of COVID-19 into a critical presentation, severely-ill patients may be benefited by its use in the early inflammatory stage and moderate doses.

Root-System Architectures of Two Cuban Rice Cultivars with Salt Stress at Early Development Stages.

Soil salinity is a critical problem for rice production and is also often associated with phosphors (P) deficiency. Plant hormones, like brassinosteroids, were shown to play a role in plant responses to different stresses and are also expected to mitigate salt stress. The aim of this study was to compare shoot growth and root architecture traits of two rice cultivars (INCA LP-5 and Perla de Cuba) during early plant development in response to salt, P limitation and a brassinosteroid. Seeds were placed in (I) paper rolls for 7 days and (II) mini-rhizotrons for 21 days without or with salt (50 mM NaCl), without or with 24-epibrassinolide (10-6 M) pre-treatment, and with two levels of P (10 or 1 ppm). The root system of LP-5 was larger in size and extent, while the roots of Perla were growing denser. Salt affected mainly the size- and extent-related root characteristics and explained about 70% of the variance. The effect of P was more pronounced without salt treatment. In Perla, P supply reduced the salt effect on root growth. The brassinosteroid had hardly any effect on the development of the plants in both experiments. Due to the high dependence on experimental factors, root length and related traits can be recommended for selecting young rice cultivars regarding salt stress and P deprivation.

Effects on Lignin Redistribution in Eucalyptus globulus Fibres Pre-Treated by Steam Explosion: A Microscale Study to Cellulose Accessibility.

The objective of this study was to investigate structural changes and lignin redistribution in Eucalyptus globulus pre-treated by steam explosion under different degrees of severity (S0), in order to evaluate their effect on cellulose accessibility by enzymatic hydrolysis. Approximately 87.7% to 98.5% of original glucans were retained in the pre-treated material. Glucose yields after the enzymatic hydrolysis of pre-treated material improved from 19.4% to 85.1% when S0 was increased from 8.53 to 10.42. One of the main reasons for the increase in glucose yield was the redistribution of lignin as micro-particles were deposited on the surface and interior of the fibre cell wall. This information was confirmed by laser scanning confocal fluorescence and FT-IR imaging; these microscopic techniques show changes in the physical and chemical characteristics of pre-treated fibres. In addition, the results allowed the construction of an explanatory model for microscale understanding of the enzymatic accessibility mechanism in the pre-treated lignocellulose.

Enhancement of Chloroprene/Natural/Butadiene Rubber Nanocomposite Properties Using Organoclays and Their Combination with Carbon Black as Fillers.

Organoclay nanoparticles (Cloisite® C10A, Cloisite® C15) and their combination with carbon black (N330) were studied as fillers in chloroprene/natural/butadiene rubber blends to prepare nanocomposites. The effect of filler type and load on the physical mechanical properties of nanocomposites was determined and correlated with its structure, compatibility and cure properties using Fourier Transformed Infrared (FT-IR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and rheometric analysis. Physical mechanical properties were improved by organoclays at 5-7 phr. Nanocomposites with organoclays exhibited a remarkable increase up to 46% in abrasion resistance. The improvement in properties was attributed to good organoclay dispersion in the rubber matrix and to the compatibility between them and the chloroprene rubber. Carbon black at a 40 phr load was not the optimal concentration to interact with organoclays. The present study confirmed that organoclays can be a reinforcing filler for high performance applications in rubber nanocomposites.

Frontotemporal brain sagging syndrome: Craniospinal hypovolemia secondary to a T6-T7 cerebrospinal fluid-venous fistula.

BACKGROUND: The frontotemporal brain sagging syndrome (FTBSS) is defined as an insidious/progressive decline in behavior and executive functions, hypersomnolence, and orthostatic headaches attributed to cerebrospinal fluid (CSF) hypovolemia. Here, a T6 CSF-venous fistula (e.g., between the subarachnoid CSF and a paraspinal vein) resulted in a CSF leak responsible for craniospinal hypovolemia. CASE DESCRIPTION: A 56-year-old male started with orthostatic headaches and fatigue after scuba diving. His symptoms included progressive, vertigo, tinnitus, nausea, lack of judgment, inappropriate behavior, memory dysfunction, apathy, tremor, orofacial dyskinesia, dysarthria, dysphagia, and hypersomnolence. The lumbar puncture revealed an opening pressure of 0 cm H2O. Magnetic resonance imaging (MRI) findings included brain sagging, bilateral temporal lobe herniation, and pachymeningeal enhancement. The computed tomography (CT) myelogram showed a thoracic diverticulum and a CSF-venous leak at the T6-T7 level. Surgery, which comprised a T6-T7 laminotomy, allowed for dissecting, clipping, and ligating the diverticulum/fistula. The patient improved postoperatively (e.g., cognitive, behavioral, and brainstem symptoms). The follow-up MRI's showed the reversion of the sagging index/uncal herniation. CONCLUSION: The FTBSS should be considered in the differential diagnosis of an early onset frontotemporal dementia. Establishing the diagnosis and localizing the site of a spinal CSF/venous leak warrant both MRI and myelogram CT studies, to pinpoint the CSF leak site for proper surgical clipping/ligation of these thoracic diverticulum/CSF-venous leaks.

The value of early and comprehensive diagnoses in a human fetus with hydrocephalus and progressive obliteration of the aqueduct of Sylvius: Case Report.

BACKGROUND: Mutant rodent models have highlighted the importance of the ventricular ependymal cells and the subcommissural organ (a brain gland secreting glycoproteins into the cerebrospinal fluid) in the development of fetal onset hydrocephalus. Evidence indicates that communicating and non-communicating hydrocephalus can be two sequential phases of a single pathological phenomenon triggered by ependymal disruption and/or abnormal function of the subcommissural organ. We have hypothesized that a similar phenomenon may occur in human cases with fetal onset hydrocephalus. CASE PRESENTATION: We report here on a case of human fetal communicating hydrocephalus with no central nervous system abnormalities other than stenosis of the aqueduct of Sylvius (SA) that became non-communicating hydrocephalus during the first postnatal week due to obliteration of the cerebral aqueduct. The case was followed closely by a team of basic and clinic investigators allowing an early diagnosis and prediction of the evolving pathophysiology. This information prompted neurosurgeons to perform a third ventriculostomy at postnatal day 14. The fetus was monitored by ultrasound, computerized axial tomography and magnetic resonance imaging (MRI). After birth, the follow up was by MRI, electroencephalography and neurological and neurocognitive assessments. Cerebrospinal fluid (CSF) collected at surgery showed abnormalities in the subcommissural organ proteins and the membrane proteins L1-neural cell adhesion molecule and aquaporin-4. The neurological and neurocognitive assessments at 3 and 6 years of age showed neurological impairments (epilepsy and cognitive deficits). CONCLUSIONS: (1) In a hydrocephalic fetus, a stenosed SA can become obliterated at perinatal stages. (2) In the case reported, a close follow up of a communicating hydrocephalus detected in utero allowed a prompt postnatal surgery aiming to avoid as much brain damage as possible. (3) The clinical and pathological evolution of this patient supports the possibility that the progressive stenosis of the SA initiated during the embryonic period may have resulted from ependymal disruption of the cerebral aqueduct and dysfunction of the subcommissural organ. The analysis of subcommissural organ glycoproteins present in the CSF may be a valuable diagnostic tool for the pathogenesis of congenital hydrocephalus.

Better detection of platelet aggregation in patients with metabolic syndrome using epinephrine and ADP.

BACKGROUND: Patients with metabolic syndrome (MS) often have increased platelet aggregation. In order to determine which concentration detects a higher level of platelet aggregation in patients with MS, the agonists ADP and epinephrine were compared. METHODS: The study included 56 subjects with MS and 53 healthy subjects. Blood pressure, weight, body-mass index, and hip-to-waist ratio were collected from all subjects. Insulin, glucose, total serum cholesterol, HDL-C, LDL-C, total triglycerides, markers of plasma atherogenicity, and indices of insulin resistance were measured in all participants. For aggregometry assays, the Born method was used. Platelets were treated with ADP and epinephrine in decreasing concentrations of 2.34, 1.17, and 0.58 µM, as well as, 11.0, 1.1, and 0.55 µM, respectively. ROC curves were plotted to define the diagnostic efficiency of epinephrine levels for MS. RESULTS: Among healthy individuals and MS patients significant differences were observed in body weight, body-mass index, waist-circumference, levels of insulin, indices of insulin resistance, and levels of HDL-cholesterol, LDL-cholesterol and total triglycerides. There was a significant difference in the detection of increased platelet aggregation using 11.0 µM and 0.55 µM epinephrine and 0.58 µM ADP. With both agonists, ROC analysis showed an area under the curve of >0.8 for 11.0 µM epinephrine and 2.34 µM ADP. However, for MS patients, 11.0 µM epinephrine had a slightly better diagnostic efficiency than 2.34 µM ADP. CONCLUSIONS: It was found that 11.0 µM epinephrine and 2.34 µM ADP detected better platelet aggregation in patients with MS than in healthy subject. Both concentrations detected increased platelet aggregation in patients with MS.

Soluble fractalkine in the plasma of fibromyalgia patients.

Fibromyalgia is a form of non-articular rheumatism in which inflammatory cytokines seem to be involved. However, there is still no analytical specific diagnostic criterion for this disease. The aim was to examine a possible role of fractalkine as a biomarker in fibromyalgia. Plasma levels of soluble fractalkine were compared between women diagnosed with fibromyalgia (n=17) and healthy women (n=10) as controls. Fractalkine released by monocytes was also evaluated. Fibromyalgia patients showed lower plasma fractalkine than healthy women. Since most inflammatory pathologies show elevated plasma levels of soluble fractalkine, the results may contribute towards a differential diagnosis for fibromyalgia.

Alternativas de derivación de LCR en pacientes de alta complejidad. Revisión de la literatura a raíz del caso de un recién nacido con Hidrocefalia post hemorrágica / Alternatives CSF shunt in patients highly complex: review of the literature following the case of a newborn with post hemorrhagic hydrocephalus

La hemorragia intraventricular (HIV) es una causa importante de daño cerebral en los recién nacidos prematuros. Su impacto negativo en el resultado del desarrollo neurológico se relaciona no sólo a su impacto directo, sino que también a las lesiones asociadas, como la hidrocefalia posthemorrágica (HPH). En la mayoría de los casos, la hidrocefalia es causada por la alteración de la reabsorción del líquido cefalorraquídeo (LCR) debido a la inflamación de las vellosidades subaracnoideas por el contacto con la sangre. El drenaje ventricular se utiliza a menudo como un procedimiento temporal para manejo de la HPH y algunos pacientes tratados con drenaje ventricular no requieren una derivación permanente; de no ser así, las derivaciones más usadas en los prematuros incluyen la ventriculoperitoneal (DVP), seguida por las derivaciones ventriculosubgaleal y ventriculoatrial. Las derivativas se consideran el tratamiento definitivo para la HPH; pero puede asociarse a complicaciones, tales como la infección, obstrucción, rechazo y el drenaje insuficiente. Otra alternativa, es la derivación ventrículopleural. Sin embargo, esta alternativa de derivación se vincula a otras complicaciones específicas, principalmente el neumotórax y el derrame pleural. Se presenta el caso clínico de EAV, quien a raíz de un parto prematuro, complicado con Hemorragia intraventricular, desarrolló Hidrocefalia y un quiste de Fosa Posterior, debiendo intervenirse en 36 oportunidades, por múltiples complicaciones. Durante su evolución se instalaron catéteres en prácticamente todos los sitios posibles, lográndose finalmente la solución del problema. Se revisa la literatura

Ventricular haemorrhage is an important cause of neurologic damage in preterm babies. Its negative impact in the final neurologic damage is not just related with the direct impact, but also with associated lesions like posthaemorrhagic hydrocephalus (PHH). In most of cases, hydrocephalus is caused by impaired cerebrospinal fluid (CEF) resorption due to the inflammation of the Arachnoid granulations because of the contact with blood. Ventricular drainage system is often used as a temporal procedure for the management of the PHH in children who have not a good response to serials lumbar punctures. Some patients treated with ventricular drainage don't need a permanent derivation, but if they do the most used in preterm babies include ventriculoperitoneal derivation (VPD) followed by ventriculosubgaleal and ventriculoatrial derivation. Derivation is considered the definitive treatment for PHH, but it can be associated with some complications as infection, obstruction and insufficient drainage. Another option is ventriculopleural derivation but this alternative is related to other complications like pneumothorax and pleural effusion. The presentation is about the case of the newborn EAV, who after preterm birth, complicated with intraventricular haemorrhage, developed hydrocephalus and a posterior fossa cyst, requiring 36 surgical interventions because of multiple complications. During its evolution he needed catheters installations in almost every possible sites, finally getting the problem solved. The literature is reviewed

A cell junction pathology of neural stem cells leads to abnormal neurogenesis and hydrocephalus.

Most cells of the developing mammalian brain derive from the ventricular (VZ) and the subventricular (SVZ) zones. The VZ is formed by the multipotent radial glia/neural stem cells (NSCs) while the SVZ harbors the rapidly proliferative neural precursor cells (NPCs). Evidence from human and animal models indicates that the common history of hydrocephalus and brain maldevelopment starts early in embryonic life with disruption of the VZ and SVZ. We propose that a "cell junction pathology" involving adherent and gap junctions is a final common outcome of a wide range of gene mutations resulting in proteins abnormally expressed by the VZ cells undergoing disruption. Disruption of the VZ during fetal development implies the loss of NSCs whereas VZ disruption during the perinatal period implies the loss of ependyma. The process of disruption occurs in specific regions of the ventricular system and at specific stages of brain development. This explains why only certain brain structures have an abnormal development, which in turn results in a specific neurological impairment of the newborn. Disruption of the VZ of the Sylvian aqueduct (SA) leads to aqueductal stenosis and hydrocephalus, while disruption of the VZ of telencephalon impairs neurogenesis. We are currently investigating whether grafting of NSCs/neurospheres from normal rats into the CSF of hydrocephalic mutants helps to diminish/repair the outcomes of VZ disruption.

A cell junction pathology of neural stem cells leads to abnormal neurogenesis and hydrocephalus

Most cells of the developing mammalian brain derive from the ventricular (VZ) and the subventricular (SVZ) zones. The VZ is formed by the multipotent radial glia/neural stem cells (NSCs) while the SVZ harbors the rapidly proliferative neural precursor cells (NPCs). Evidence from human and animal models indicates that the common history of hydrocephalus and brain maldevelopment starts early in embryonic life with disruption of the VZ and SVZ. We propose that a "cell junction pathology" involving adherent and gap junctions is a final common outcome of a wide range of gene mutations resulting in proteins abnormally expressed by the VZ cells undergoing disruption. Disruption of the VZ during fetal development implies the loss of NSCs whereas VZ disruption during the perinatal period implies the loss of ependyma. The process of disruption occurs in specific regions of the ventricular system and at specific stages of brain development. This explains why only certain brain structures have an abnormal development, which in turn results in a specific neurological impairment of the newborn. Disruption of the VZ of the Sylvian aqueduct (SA) leads to aqueductal stenosis and hydrocephalus, while disruption of the VZ of telencephalon impairs neurogenesis. We are currently investigating whether grafting of NSCs/neurospheres from normal rats into the CSF of hydrocephalic mutants helps to diminish/repair the outcomes of VZ disruption.

El estrés por temperatura provoca necrosis en tabaco negro; cuantificación por análisis de imágenes / Temperature stress provoke necrosis in black tobacco; quantification by image analysis

El tabaco negro (Nicotiana tabacum L.) es un importante cultivo económico en Cuba por su uso en la manufactura de puros Habanos. Factores bióticos y abióticos lo afectan, de ahí que sea valioso el estudio de los daños fisiológicos que le produce el estrés. El objetivo de este trabajo fue cuantificar los efectos del estrés por temperatura sobre el daño por necrosis en hojas, y determinar la acumulación de peróxido de hidrógeno (H2O2) in situ en los tejidos de Nicotiana tabacum L. (variedad Habana-2000). Se aplicaron diferentes tratamientos de temperatura (4 ºC, 25 ºC, 45 ºC y 60 ºC) a hojas de plantas de 4 semanas de edad; la necrosis se reveló con solución de azul de tripano. El área de tejidos con acumulación de peróxido (H2O2) en plántulas completas de 7 días de edad, sometidas a las mismas condiciones de estrés, se determinó con DAB. Se estimó el porcentaje de área necrosada y de acumulación de H2O2 utilizando el programa de análisis y procesamiento de imágenes ImageJ. Este programa es capaz de adquirir, mostrar, editar, resaltar y analizar imágenes. Se demostró que las hojas sometidas a 4 ºC, independientemente del tiempo de exposición, presentaron una mayor área necrosada (35 por ciento) en comparación con el resto de los tratamientos. Las áreas con acumulación de H2O2 in situ fueron mayores en los tratamientos de estrés por temperaturas altas (45 y 60°C). La detección y cuantificación de la necrosis producida por temperaturas extremas, combinando el método del azul de tripano con el análisis de imágenes, es una herramienta útil para valorar los daños producidos por estrés de temperaturas y pudiera ser utilizado para valorar los daños celulares provocados por otros tipos de estrés

Metabolismo mineral óseo durante la gestación y efectos sobre la masa ósea de la madre / Bone mineral metabolism during gestation and its effects on maternal bone mass

La gestación y lactancia son periodos de alta demanda de calcio, para el crecimiento fetal y para la producción de leche materna. Durante la gestación, la madre transfiere al feto 25 a 30 g de calcio y durante la lactancia se secretan 200 a 240 mg de calcio diario en la leche materna. Durante la gestación, los mecanismos adaptativos más importantes son el incremento en la absorción de calcio y el incremento del recambio óseo materno; durante la lactancia, hay tendencia a conservar más calcio a nivel renal, pero la desmineralización temporal del esqueleto materno parece ser el mecanismo más importante. Los estudios que emplean absorciometría dual de rayos X (DXA) son escasos, por el riesgo de radiación materna y fetal; pero, con otras técnicas, como el ultrasonido cuantitativo, se ha descrito una pérdida de masa ósea durante la gestación predominantemente dependiente del hueso trabecular. Mediante marcadores bioquímicos del remodelamiento óseo se ha demostrado que los suplementos de calcio reducen la tasa de remodelamiento durante el embarazo y parecen tener efecto benéfico sobre la pérdida ósea materna. Estudios longitudinales que emplean ultrasonido cuantitativo también han encontrado una disminución de la pérdida ósea, entre las mujeres que recibieron aporte o suplemento adecuado de calcio durante la gestación.

Pregnancy and lactation are periods of high calcium demand for skeletal growth and maternal milk production. Approximately 25-30 g of calcium are transferred to the fetus during pregnancy, and breast-feeding mothers secrete 200-240 mg/day of calcium in breast milk every day. During pregnancy, major physiologic adaptations include increased both calcium intestinal absorption and rate of maternal bone turnover; during lactation, there is a contribution of renal calcium conservation, but temporary maternal bone demineralization is the main mechanism to meet calcium requirements. Data on bone mineral density assessed by dual energy x-ray absortiometry (DXA) are sparse mainly due to concern about potential risk of radiation exposure to the fetus. Other radiation-free techniques like quantitative ultrasound have been used to assess maternal bone mass changes during pregnancy. Maternal bone loss mainly depending on trabecular areas during pregnancy has been described. Calcium supplements reduce maternal skeletal-bone turnover as evaluated by bone resorption markers during pregnancy and seem to have beneficial effects on maternal bone loss. Longitudinal studies with repeated measurements of quantitative ultrasound during pregnancy have found decrease in bone loss in pregnant women with adequate calciumin take or supplementation.

La inoculación de plantas con Pantoea sp., bacteria solubilizadora de fosfatos, incrementa la concentracion de P en los tejidos foliares / Plant inoculation with Pantoea sp., phosphate solubilising-bacteria increases P concentration in leaf tissues

El fósforo (P) es un macronutriente mineral esencial para las plantas. Aunque puede encontrarse en los suelos en diferentes formas minerales, la baja solubilidad de estos disminuye su disponibilidad para las plantas, y el nutriente debe aplicarse como fertilizante a los cultivos. Las reservas mundiales de P son limitadas y tendrán una reducción considerable en los próximos años. Usar microorganismos solubilizadores de fosfatos como inoculante para los cultivos es una alternativa biotecnologica para incrementar la disponibilidad del nutriente. Pantoea sp. (cepa 9C) es una bacteria endofitica fijadora de nitrogeno, aislada del interior de tallos de la caña de azucar (Loiret et al., 2004); este microorganismo produjo halos de solubilizacion con tamaños de hasta 6 mm en medio sólido NBRI-P en 7 dias a 30 grados centigrados, y en ese tiempo y condiciones solubilizo Ca3(PO4)2 en el medio líquido hasta acumular 1128 μg P mL-1. La bacteria sobrevivio durante 35 días en un sustrato preparado con mezcla de Vermiculita y suelo ferralítico rojo (Cambisol Ferrálico, ródico), alcanzando poblaciones de 3,2 x 1015 células g-1. Plantas de rábano (Raphanus sativus, L. var. Scarlet Globe), de alta demanda de P y crecimiento rápido, usadas como modelo y cultivadas en suelos inoculados con el microorganismo, absorbieron mas P que las plantas no inoculadas, alcanzando en los tejidos foliares concentraciones ≥ 3500 ppm P base seca.

Spores of the mycorrhizal fungus Glomus mosseae host yeasts that solubilize phosphate and accumulate polyphosphates.

The present paper reports the presence of bacteria and yeasts tightly associated with spores of an isolate of Glomus mosseae. Healthy spores were surface disinfected by combining chloramine-T 5%, Tween-40, and cephalexin 2.5 g L(-1) (CTCf). Macerates of these spores were incubated on agar media, microorganisms were isolated, and two yeasts were characterized (EndoGm1, EndoGm11). Both yeasts were able to solubilize low-soluble P sources (Ca and Fe phosphates) and accumulate polyphosphates (polyPs). Sequence analysis of 18S ribosomal deoxyribonucleic acid showed that the yeasts belong to the genera Rhodotorula or Rhodosporidium (EndoGm1) and Cryptococcus (EndoGm11). Results from inoculation experiments showed an effect of the spore-associated yeasts on the root growth of rice, suggesting potential tripartite interactions with mycorrhizal fungi and plants.