Adaptation and learning as strategies to maximize reward in neurofeedback tasks.

Introduction: Adaptation and learning have been observed to contribute to the acquisition of new motor skills and are used as strategies to cope with changing environments. However, it is hard to determine the relative contribution of each when executing goal directed motor tasks. This study explores the dynamics of neural activity during a center-out reaching task with continuous visual feedback under the influence of rotational perturbations. Methods: Results for a brain-computer interface (BCI) task performed by two non-human primate (NHP) subjects are compared to simulations from a reinforcement learning agent performing an analogous task. We characterized baseline activity and compared it to the activity after rotational perturbations of different magnitudes were introduced. We employed principal component analysis (PCA) to analyze the spiking activity driving the cursor in the NHP BCI task as well as the activation of the neural network of the reinforcement learning agent. Results and discussion: Our analyses reveal that both for the NHPs and the reinforcement learning agent, the task-relevant neural manifold is isomorphic with the task. However, for the NHPs the manifold is largely preserved for all rotational perturbations explored and adaptation of neural activity occurs within this manifold as rotations are compensated by reassignment of regions of the neural space in an angular pattern that cancels said rotations. In contrast, retraining the reinforcement learning agent to reach the targets after rotation results in substantial modifications of the underlying neural manifold. Our findings demonstrate that NHPs adapt their existing neural dynamic repertoire in a quantitatively precise manner to account for perturbations of different magnitudes and they do so in a way that obviates the need for extensive learning.

Adenomyosis in Pregnancy-Should It Be Managed in High-Risk Obstetric Units?

BACKGROUND: Uterine adenomyosis is an increasingly frequent disorder. Our study aimed to demonstrate the presence of obstetric complications in the population affected by this condition to demonstrate the need for follow-up in high-risk obstetric units. MATERIAL AND METHODS: The data for the study were obtained from TriNetX, LLC, between 2010 and 2020. The outcomes analyzed were intrauterine growth restriction (IUGR), preterm delivery, cesarean delivery, hypertension, abruption placentae, and spontaneous abortion. Seven thousand six hundred and eight patients were included in the cohort of pregnant patients with adenomyosis, and 566,153 women in the cohort of pregnant patients without any history of endometriosis. RESULTS: Upon calculating the total risk of presenting any of these problems during pregnancy, we obtained an OR = 1.521, implying that a pregnancy with adenomyosis was 52.1% more likely to present some complication. We found: IUGR OR = 1.257 (95% CI: 1.064-1.485) (p = 0.007); preterm delivery OR = 1.422 (95% CI: 1.264-1.600) (p = 0.0001); cesarean delivery OR = 1.099 (95% CI: 1.002-1.205) (p = 0.046); hypertensive disorders OR = 1.177 (95% CI: 1.076-1.288) (p = 0.0001); abruption placentae OR = 1.197 (95% CI: 1.008-1.422) (p = 0.040), and spontaneous abortion OR = 1.529 (95% CI: 1.360-1.718) (p = 0.0001). CONCLUSION: We conclude that the review carried out and the data we obtained on increased risk provide sufficient evidence to recommend that patients with adenomyosis should be managed in obstetric high-risk units.

[Photo-based examination for diabetic eye pathologies in a German ophthalmological practice without personal doctor-patient contact]. / Fotobasierte Untersuchung auf diabetische Augenveränderungen in einer deutschen Augenarztpraxis ohne direkten Arzt-Patienten-Kontakt.

BACKGROUND: An increasing number of patients suffering from diabetes require regular ophthalmological check-ups to diagnose and/or treat potential diabetic retinal disease. Some countries have already implemented systematic fundus assessments including artificial intelligence-based programs in order to detect sight-threatening retinopathy. The aim of this study was to improve the detection of diabetic fundus changes in Germany without examination by a doctor and to create an easy access to ophthalmological examinations. MATERIAL AND METHODS: In this prospective monocentric study 93 patients in need for a routine check-up for diabetic retinopathy were included. The study participants took up an offer of an examination (visual examination, non-mydriatic camera-based fundus examination) without doctor-patient contact. Patient satisfaction with the organization and examinations was assessed using a questionnaire. RESULTS: The mean age was 53.5 years (SD 13.6 years, 49.5% female) and 17 eyes (18.3%) showed a diabetic retinopathy which was detected using a camera-based examination. Within the small sample, no patient had to repeat the examination due to poor image quality. All categories of the questionnaire showed a good to very good satisfaction, indicating a high acceptance of the other examination form that took place at the ophthalmologist's premises. CONCLUSION: In our study in an ophthalmological practice a high level of acceptance among the patients interested in the screening for diabetic retinopathy without any direct patient-doctor contact was achieved. Our study shows a very good acceptance and feasibility. Future use of artificial intelligence in clinical practice may help to be able to screen many more patients as in this study imaging quality was very good.

Survival study and factors associated with mortality in Chilean patients on peritoneal dialysis infected with SARS-CoV-2.

The Covid-19 pandemic has been responsible for millions of deaths worldwide. Patients with comorbidities- such as those on peritoneal dialysis (PD)- present higher morbidity and mortality than the general population. We prospectively evaluated all Chilean patients on PD (48 centres) and followed those who had Covid-19 from the beginning of the Covid-19 pandemic in Chile (March 2020) to January 2021 (start of vaccination campaign). We described demographic history, comorbidities, factors related to infection, need for hospitalisation and death due to Covid-19. During the study period, 106 adults on PD were infected by SARS-CoV-2, with a mean age of 53.1 (±16.3) and of which 53.9% were female. From that group, 54.8% required hospitalisation and 24.5% (n = 26) died due to Covid-19. Most of the patients (63.4%) were infected at home and 22.8% during hospitalisation for other reasons. There was a significant association for Covid-19 mortality with: being ≥60 years old, diabetes, time on PD ≥5 years, need for hospitalisation and hospital-acquired infection. At 90 days of follow-up, all deaths associated to Covid-19 occurred before 40 days. We conclude that patients on PD without Covid-19 vaccination have a high mortality and need for hospitalisation associated to Covid-19. To avoid this negative outcome, it is necessary to intensify strategies to avoid contagion, especially in those ≥60 years old, with diabetes and/or ≥5 years spent on PD.

[Metformin-associated lactic acidosis. Report of one case]. / Acidosis láctica asociada a metformina. Caso clínico.

Metformin-associated lactic acidosis is a severe and infrequent adverse event. Early diagnosis is essential to start an early treatment, which often has favorable results. We report a 56 years old non-insulin-requiring type 2 diabetic female who developed a severe metabolic acidosis associated with metformin in relation to an acute renal failure secondary to infectious diarrhea. Early treatment with bicarbonate and continuous hemofiltration allowed a quick improvement of the patient. Metformin-associated lactic acidosis has an elevated mortality (50-80%) and has a specific and effective treatment. Therefore, the condition must be born in mind.

Acidosis láctica asociada a metformina: caso clínico / Metformin-associated lactic acidosis: report of one case

Metformin-associated lactic acidosis is a severe and infrequent adverse event. Early diagnosis is essential to start an early treatment, which often has favorable results. We report a 56 years old non-insulin-requiring type 2 diabetic female who developed a severe metabolic acidosis associated with metformin in relation to an acute renal failure secondary to infectious diarrhea. Early treatment with bicarbonate and continuous hemofiltration allowed a quick improvement of the patient. Metformin-associated lactic acidosis has an elevated mortality (50-80%) and has a specific and effective treatment. Therefore, the condition must be born in mind.

Correlation between predialysis systolic blood pressure and predialysis hydration status in hemodialysis patients / Correlación entre la presión arterial sistólica prediálisis y el estado de hidratación prediálisis en pacientes de hemodiálisis

One of the goals of hemodialysis is to maintain normal hydration status in ESRD patients.Pre hemodialysis systolic blood pressure is usually used as a clinical parameter of hydration status and to set ultrafiltration rate before Hd. It is unclear how much pre-Hd SBP correlated with hydration status. The aimwas to determine correlation between pre-Hd SBP and hydration status before Hd. An observational correlation study was performed in two dialysis centers in Santiago, Chile, from January-June, 2011. Adult patients inHd for at least three months, who gave their informed consent were included. Patients with pacemaker,amputee, hospitalized and metallic prostheses were excluded. Total-body water and over hydrated were assessed with bioimpedance spectroscopy before the first and third dialysis session of the week. Pre-Hd SBP,pre-Hd body weight, pre-Hd TBW and pre-Hd OH, were analyzed using Pearson correlation and linear regressionmodel. 96 measurements were assessed, 52 % were male with median age 59.5 years. The correlationbetween pre-Hd SBP and pre-Hd overhydration was r=0.33, and total body water r=0.15, with a predictedvalue, R2=0.10 and R2 =0.14 respectively. Pre-Hd SBP had low correlation with pre-Hd hydration status and by itself, is not a reliable parameter to set ultrafiltration rate before Hd. Nevertheless Pre-Hd body weight predicted in 70 % the pre-Hd TBW.

Uno de los objetivos de la hemodiálisis es mantener la hidratación normal en pacientes ESRD. La presión arterial sistólica pre hemodiálisis, es usualmente utilizada como parámetro clínico del estado de hidratación y para fijar la velocidad de ultrafiltración antes de la hemodialisis. No está claro cuanto se correlacionan la presión arterial sistólica prehemodialysis con el estado de hidratación. El objetivo fue determinar la correlación entre la PAS prehemodiálisis y el estado de hidratación antes de Hd. Se realizó un estudio de correlación observacional en dos centros de diálisis de Santiago de Chile, de Enero a Junio de 2011. Se incluyeron pacientes adultos en HD durante al me-nos tres meses que dieran su consentimiento informado. Se excluyeron los pacientes con marcapasos, amputados, hospitalizados y pró-tesis metálicas. El agua corporal total y el exceso de hidratación se evaluaron con espectroscopia 1030 de bioimpedancia antes de la primera y tercera sesión de diálisis de la semana. Pre-Hd PAS, pre-Hd peso corporal, pre-Hd ACT y pre-Hd OH, se analizaron utilizando el modelo de correlación y regresión lineal de Pearson. Se evaluaron 96 mediciones, 52% eran hombres con edad media 59, 5 años. La correlación entre la PAS pre-Hd y la sobrehidratación pre-Hd fue r=0, 33 y agua corporal total r=0, 15, con un valor predicho, R2= 0, 10 y R2 = 0, 14 respectivamente. Existe baja correlación entre la PAS Pre-Hd con el esta-do de hidratación pre-Hd y por lo mismo, no es un parámetro confiable para establecer la tasa de ultrafiltración antes de Hd. Sin embargo, el peso corporal Pre-Hd predijo en un 70% el agua corporal total pre-Hd.

Three-Dimensional Hysterosalpingo-Contrast-Sonography for the Assessment of Tubal Patency in Women with Infertility: A Systematic Review with Meta-Analysis.

BACKGROUND/AIMS: We aimed at performing a systematic review to determine the diagnostic accuracy of three-dimensional (3D) hysterosalpingo-contrast-sonography (HyCoSy) for detecting tubal occlusion. METHODS: A systematic review in Medline database search from January 1989 to October 2015 to identify relevant studies evaluating 3D-HyCoSy. Eligibility criteria were studies assessing the role of 3D-HyCoSy for diagnosing tubal occlusion in infertile women. Index test was 3D-HyCoSy. Reference standard was laparoscopy with dye test or X-ray hysterosalpingography. Quality was assessed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and Quality Assessment of Diagnostic Accuracy Studies-2 tool. Pooled sensitivity and specificity for the method were estimated. RESULTS: A total number of 88 papers were identified. After exclusions, nine studies were ultimately included. Pooled estimated sensitivity was 98% (95% CI 91-100) with a moderate heterogeneity (I2: 64.8%, 95% CI 39.6-89.9; and Cochran Q 22.7, p < 0.001). Pooled estimated specificity was 90% (95% CI 83-95) with significant heterogeneity (I2: 80.3%, 95% CI 68.1-92.5; and Cochran Q 40.6, p < 0.001). Positive likelihood ratio was 10.3 (95% CI 5.6-18.7) and negative likelihood ratio was 0.02 (95% CI 0.00-0.21). CONCLUSION: 3D-HyCoSy is an accurate test for diagnosing tubal occlusion in women with infertility.

Transvaginal/transrectal ultrasound for assessing myometrial invasion in endometrial cancer: a comparison of six different approaches.

OBJECTIVE: To compare the diagnostic performance of six different approaches for assessing myometrial infiltration using ultrasound in women with carcinoma of the corpus uteri. METHODS: Myometrial infiltration was assessed by two-dimensional (2D) transvaginal or transrectal ultrasound in 169 consecutive women with well (G1) or moderately (G2) differentiated endometrioid type endometrial carcinoma. In 74 of these women three-dimensional (3D) ultrasound was also performed. Six different techniques for myometrial infiltration assessment were evaluated. The impression of examiner and Karlsson's criteria were assessed prospectively. Endometrial thickness, tumor/uterine 3D volume ratio, tumor distance to myometrial serosa (TDS), and van Holsbeke's subjective model were assessed retrospectively. All subjects underwent surgical staging within 1 week after ultrasound evaluation. Definitive histopathological data regarding myometrial infiltration was used as gold standard. Sensitivity and specificity for all approaches were calculated and compared using McNemar test. RESULTS: The impression of examiner and subjective model performed similarly (sensitivity 79.5% and 80.5%, respectively; specificity 89.6% and 90.3%, respectively). Both methods had significantly better sensitivity than Karlsson's criteria (sensitivity 31.8%, p<0.05) and endometrial thickness (sensitivity 47.7%, p<0.05), and better specificity than tumor/uterine volume ratio (specificity 28.3%, p<0.05) and TDS (specificity 41.5%, p<0.05). CONCLUSION: Subjective impression seems to be the best approach for assessing myometrial infiltration in G1 or G2 endometrioid type endometrial cancer by transvaginal or transrectal ultrasound. The use of mathematical models and other objective 2D and 3D measurement techniques do not improve diagnostic performance.

Deviations of the glass transition temperature in amorphous conjugated polymer thin films.

The deviations of the glass transition temperature (T(g)) in thin films of an amorphous conjugated polymer poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine) (TFB) are reported. Monotonic and nonmonotonic T(g) deviations are observed in TFB thin films supported on Si-SiOx and poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS), respectively. A three-layer model is developed to fit both monotonic and nonmonotonic T(g) deviations in these films. A 5-nm PEDOT:PSS capping layer was not found to be effective to remove the free-surface effect in Si-SiOx supported TFB films.

Luxación congénita de rodilla, a propósito de un caso / Congenital dislocation of the Knee, a case report

La luxación congénita de rodilla es una entidad de muy baja incidencia (0.017 casos por mil nacidos vivos) y 1 por 100.000 casos en relación con la displasia de cadera y que puede presentarse en forma aislada o como parte de algunas entidades teratológicas (síndrome de Down, artrogriposis, mielomeningocele, etc.). Describimos a un neonato, de sexo femenino, que presenta una rodilla izquierda en hiper-extensión, asociado a genu valgo, pie plano valgo y displasia de cadera del mismo lado. De inicio, el manejo fue conservador, pero frente al fracaso terapéutico tuvo que ser intervenido quirúrgicamente para lograr la rehabilitación del paciente. Concluimos que la intervención quirúrgica debe ser precoz y oportuna en esta afección.

Congenital dislocation of the knee is a very rare disease (0.017 cases/1000 live newborns and 1/100.000 in relation to hip dysplasia). Usually is an isolated finding, but some times it is associated to other entities (Down syndrome, arthrogriposis, myelomeningocele, etc). We describe a female newborn who presented at birth hyperextend left knee, genu valgo, flat foot and hip dysplasia of the same side. She was treated conservatively with no improvement, so she underwent surgery and later rehabilitation. We conclude that surgery should be early and the first line of treatment of this condition.

The role of TASK-like K+ channels in oxygen sensing in the carotid body.

The carotid body plays an important role in initiating protective responses to hypoxemia. The primary oxygen sensing cells are the glomus or type 1 cells. Hypoxia evokes the secretion of neurotransmitters from these cells which then excite afferent nerves. This response is mediated via membrane depolarization and voltage-gated Ca2+ entry. Studies from this laboratory have revealed that membrane depolarization in response to hypoxia is primarily the result of inhibition of background K+ channels which show strong similarities to the acid sensitive tandem-P-domain K+ channels TASK-1 and TASK-3. The background K+ channels of type-1 cells are also very sensitive to inhibition of mitochondrial energy metabolism and, in excised patches, appear to be directly activated by ATP. Thus these TASK-like background channels would appear to confer the ability to sense changes in oxygen levels, pH and metabolism upon the type 1 cell. The key issue of whether the effects of hypoxia are mediated through changes in metabolism remains unanswered but the effects of inhibition of mitochondrial energy metabolism and of hypoxia upon background K+ channels is mutually exclusive suggesting that there is a close link between metabolism and oxygen sensing in the type 1 cell.

[Severe hyperkalemia associated to the use of losartan and spironolactone: case report]. / Hiperkalemia grave asociada a drogas que actúan sobre el sistema renina, angiotensina, aldosterona: un problema que requiere atención. Caso clínico.

Hyperkalemia is a complications of the use of angiotensin converting enzyme inhibitors, angiotensin receptor antagonists and aldosterone antagonists. These drugs are commonly used for the treatment of hypertension and cardiac failure. We report a 84 year-old female treated with losartan 50 mg/day and spironolactone 25 mg/day that presented with a hyperkalemia of 8.4 mEq/l and bradicardia, drowsiness and respiratory depression. She required hemodialysis and ventilatory assistance. She was discharged in good conditions five days after admission.