Plackett-Burman design in the biosynthesis of silver nanoparticles with Mutisia acuminatta (Chinchircoma) and preliminary evaluation of its antibacterial activity.

Background: The aim of this study was to synthesize silver nanoparticles (AgNPs) using the methanolic fraction of Mutisia acuminatta leaves using Plackett-Burman design to optimize process parameters and to evaluate its antibacterial effect. Methods: For the separation of Mutisia acuminatta phytoconstituents, chromatographic techniques were used. For characterization and identification, UV - VIS spectrophotometry, FTIR spectrophotometry, Dynamic Light Scattering (DLS) and transmission electron microscopy (TEM) were used. The Plackett-Burman design used polynomial regression statistical analysis to determine the most influential variables. Results: UV-VIS spectroscopy reported an absorbance concerning surface plasmon resonance between 410-420 nm wavelength for the AgNPs. FTIR spectrophotometry reported characteristic peaks in the biosynthesized AgNPs, observing the disappearance of spectral peaks between 1000-1500 cm -1. By UHPLC-MS, caffeic acid derivatives, coumarins, flavonoids, lignans, disaccharide and a complex formed between silver and the solvent (AgCH3CN+) were identified. Using DLS, the AgNPs presented an average hydrodynamic size of 45.91 nm. TEM determined the spherical shape of the AgNPs, presenting diameters in the range of 30 to 60 nm. The biosynthesized AgNPs showed higher antibacterial activity against Escherichia coli and Staphylococcus aureus than the total extract, the methanolic fraction and pure methanol. The polynomial model in the biosynthesis was validated with an adequate fitting representing the experimental data of the process. The most significant variables for the model obtained were the reaction pH (X 2) and the concentration of the precursor salt AgNO 3 (X 6). Conclusions: The synthesized AgNPs offer a viable option for further development due to the presence of bioactive compounds, adequate characterization and antibacterial activity.

Effects of virtual reality-based motor rehabilitation: a systematic review of fMRI studies.

Background.The use of virtual reality (VR) as a rehabilitation tool has been shown to induce motor and cognitive improvements in different populations. Functional magnetic resonance imaging (fMRI) has been used to investigate neuroplasticity resulting from these treatments. We hypothesize that VR rehabilitation induces functional improvement and brain changes that can be detected by fMRI.Objective.To systematically review the effects of VR intervention on the cortical reorganization measured by fMRI and associated with functional improvement.Approach.We performed a systematic review of studies published between 2005 and 2021. Papers were retrieved from six databases using the following keywords: 'motor rehabilitation', 'fMRI' and 'virtual reality'. Case studies, pre-post studies, cross-sectional studies, and randomized controlled trials published were included. Manuscripts were assessed by The National Institutes of Health study quality assessment tools to determine their quality.Main results.Twenty-three articles met our eligibility criteria: 18 about VR rehabilitation in stroke and five on other clinical conditions (older adults, cerebral palsy, and Parkinson's disease). Changes in neural patterns of activation and reorganization were revealed in both the ipsilesional and the contralesional hemispheres. Results were located mainly in the primary motor cortex, sensorimotor cortex and supplementary motor area in post-stroke patients in the acute, subacute, and chronic rehabilitation phases, and were associated with functional improvement after VR intervention. Similar effects were observed in older adults and in patients with other neurological diseases with improved performance.Significance.Most stroke-related studies showed either restoration to normal or increase of activation patterns or relateralization at/to the ipsilesional hemisphere, with some also reporting a decrease in activity or extent of activation after VR therapy. In general, VR intervention demonstrated evidence of efficacy both in neurological rehabilitation and in performance improvement of older adults, accompanied by fMRI evidence of brain reorganization.

Morphological diversity and discrimination tools of the non-marine ostracod Cypridopsis silvestrii across temporal and spatial scales from Patagonia.

Geometric morphometric methods are powerful tools to discriminate between closely related ostracods taxa as well as to study the relationship between their morphological variations, taxonomy and paleoecology. In this study, valve outline analysis allows the discrimination between the non-marine ostracod C. silvestrii and R. whatleyi juveniles, pointing out differences in the posterior valve area and surface ornamentation. Modern female specimens of C. silvestrii from 23 sites located in a spatial transect (41 to 51 °S) exhibited extensive morphological variability, on the basis of which three morphotypes (acuminated, transitional, subtruncated) were determined. Multivariate analyses showed that acuminated and transitional shapes are not arranged in groups but the subtruncated morphotype, previously described as E. cecryphalium, seems to be associated with low water conductivity (372 µS cm-1), dominant cold (5 ºC) and windy (8.6 m s-1) climatic conditions. The fossil cluster which included nine cores spanning the last 15.6 kyr, only covered acuminated and transitional shapes, which may indicate that these lineages might be older than the subtruncated morphotype. In addition, morphological differences between reproduction modes suggested that parthenogenetic females exhibit de posterior margin more acuminate than sexual females. These results set the ground for more precise ecological and paleoenvironmental studies in Patagonia.

Taxonomic revision of Cypridopsis silvestrii comb. nov. (Ostracoda, Crustacea) from Patagonia, Argentina with morphometric analysis of their intraspecific shape variability and sexual dimorphism.

In this study we redescribe an ostracod species belonging to the subfamily Cypridopsinae Kaufmann, 1900, sampled in seven localities of northern and southern Patagonia, Argentina. A new taxonomical combination is proposed, Cypridopsis silvestrii comb. nov., based on detailed description of females and the first descriptions of males. Cypridopsis silvestrii occurred on a wide geographical distribution range, from 40º to 48º S latitude, as well as broad environmental tolerance ranges. We evaluated morphological variations in two populations of C. silvestrii from northern (El Toro lake) and southern (El Sello lake) Patagonia, with contrasting limnological conditions. El Toro is a small shallow lake with high salinity waters and El Sello is a large deep lake with lower salinity. Based on morphometric analysis, our results showed intraspecific variation in valve shape and size between populations. Sexual dimorphism in El Toro population was identified through morphometric analyses. Additionally, comparison of valve outlines in living and subfossil individuals from El Toro lake allowed specimens previously described as juveniles of Eucypris fontana (Graf, 1931) to be identified as adults of C. silvestrii comb. nov. The present contribution increases knowledge of the taxonomic identity, the ecological requirements and the geographical distribution of C. silvestrii, and shows that morphometric analyses are a feasible and useful tool for exploring intraspecific shape differences and assisting in taxonomic identification. Furthermore, the results presented herein provide tools for C. silvestrii identification in paleolimnological studies, and emphasize the usefulness of studying living representatives for clarification of the taxonomic status of species widely distributed in Quaternary sediments.

Increase in Short-Interval Intracortical Facilitation of the Motor Cortex after Low-Frequency Repetitive Magnetic Stimulation of the Unaffected Hemisphere in the Subacute Phase after Stroke.

Low-frequency repetitive transcranial magnetic stimulation of the unaffected hemisphere (UH-LF-rTMS) in patients with stroke can decrease interhemispheric inhibition from the unaffected to the affected hemisphere and improve hand dexterity and strength of the paretic hand. The objective of this proof-of-principle study was to explore, for the first time, effects of UH-LF-rTMS as add-on therapy to motor rehabilitation on short-term intracortical inhibition (SICI) and intracortical facilitation (ICF) of the motor cortex of the unaffected hemisphere (M1UH) in patients with ischemic stroke. Eighteen patients were randomized to receive, immediately before rehabilitation treatment, either active or sham UH-LF-rTMS, during two weeks. Resting motor threshold (rMT), SICI, and ICF were measured in M1UH before the first session and after the last session of treatment. There was a significant increase in ICF in the active group compared to the sham group after treatment, and there was no significant differences in changes in rMT or SICI. ICF is a measure of intracortical synaptic excitability, with a relative contribution of spinal mechanisms. ICF is typically upregulated by glutamatergic agonists and downregulated by gabaergic antagonists. The observed increase in ICF in the active group, in this hypothesis-generating study, may be related to M1UH reorganization induced by UH-LF-rTMS.

Abusive head trauma at a tertiary care children's hospital in Mexico City. A preliminary study.

OBJECTIVES: Determine the prevalence, clinical signs and symptoms, and demographic and family characteristics of children attending a tertiary care hospital in Mexico City, Mexico, to illustrate the characteristics of abusive head trauma among this population. METHODS: This is a cross-sectional descriptive study of infants and children under 5, who suffered head trauma and were admitted to the National Pediatrics Institute in Mexico City, a tertiary care referral center. We reviewed medical records and extracted data on clinical and neurological signs and symptoms, fundus, radiological (long bones, thorax, CAT scan), and laboratory tests. We administered a standardized questionnaire assessing child abuse and neglect to the parents of the children included in the study. RESULTS: One hundred and twenty children, under 5 presenting with head trauma, were recruited, 13 (11%) were considered abusive head trauma (AbHT) and 107 (89%) were diagnosed as accidental head injury (AcHI). The AbHT group comprised younger infants (mean age 8 months) and the AcHI group included toddlers about an average of 25 months. To account for this significant age difference, we performed a comparison of age matched cases. The children in the AbHT were more likely to be female, the result of the first unintended pregnancy and the children of younger mothers (17-19). Mothers in this group had attended fewer than 5 prenatal care visits and fathers had a history of alcohol abuse. Five (38%) of the 13 AbHT children did not survive their injuries and overall showed greater neurological and respiratory compromise, increased prothrombin time (PT), and lower hematocrit values. The most common intracranial injuries suffered by children in the AbHT group were subdural/epidural hematoma and parenchymal/subarachnoid hemorrhage. Retinal hemorrhage was the most frequent ocular injury. CONCLUSIONS: In a tertiary care children's hospital, 11% of the children presenting with head trauma, were considered of abusive origin. Unintended pregnancy among teen mothers and substance abuse in the father were associated with abusive head trauma in this descriptive study.

[Gynecological clinical study in girls and adolescent victims of sexual abuse]. / Estudio clínico ginecológico en niñas y adolescentes que sufrieron abuso sexual.

In spite of a very important under-registration, sexual abuse represents a social and public health problem worldwide. In Mexico, estimated prevalence of sexual abuse in women is 17.3%, half of them in youngsters under 15 years old. Most of cases have a late gynecological evaluation, due to a delay in a formal complaint. Gynecologist or pediatrician are the specialists who most frequently perform the genital examination of girls suspected of sexual abuse, due to this a complete knowledge of the topic is necessary in order to make an accurate diagnosis, register the physical findings and give prompt medical and psychological treatment as well as follow up to the patient. Despite the low risk of acquiring a sexually transmitted infection, it is important to evaluate the use of prophylactic treatment and the prevention of unwanted pregnancy with emergency contraception. Big efforts are being made by preventive programs on sexual abuse, sexually transmitted infections and unwanted pregnancy, all of which are serious problems in Mexican children and youths, and should constitute a fundamental part of the public politics on sexual health.