Probing the mechanism for hydrogel-based stasis induction in human pluripotent stem cells: is the chemical functionality of the hydrogel important?

It is well-known that pluripotent human embryonic stem cells (hPSC) can differentiate into any cell type. Recently, we reported that hPSC colonies enter stasis when immersed in an extremely soft hydrogel comprising hydroxyl-functional block copolymer worms (I. Canton, N. J. Warren, A. Chahal, K. Amps, A. Wood, R. Weightman, E. Wang, H. Moore and S. P. Armes, ACS Centr. Sci., 2016, 2, 65-74). The gel modulus and chemical structure of this synthetic hydrogel are similar to that of natural mucins, which are implicated in the mechanism of diapause for mammalian embryos. Does stasis induction occur merely because of the very soft nature of such hydrogels or does chemical functionality also play a role? Herein, we address this key question by designing a new hydrogel of comparable softness in which the PGMA stabilizer chains are replaced with non-hydroxylated poly(ethylene glycol) [PEG]. Immunolabeling studies confirm that hPSC colonies immersed in such PEG-based hydrogels do not enter stasis but instead proliferate (and differentiate if no adhesion substrate is present). However, pluripotency is retained if an appropriate adhesion substrate is provided. Thus, the chemical functionality of the hydrogel clearly plays a decisive role in the stasis induction mechanism.

Influence of Background Noise Produced in University Facilities on the Brain Waves Associated With Attention of Students and Employees.

As a consequence of noise exposure, lack of attention badly affects directly the academic and work performance. The study of the brain and the waves that it produces is the most objective way to evaluate this process. Attentional improvement is associated with increases of the amplitude in both beta and theta bands. The objective of this work is to study the influence of background noise produced inside university facilities on changes in the cerebral waves related to attention processes (beta 13-30 Hz and theta 4-7 Hz). Volunteers were asked to perform a specific task in which attention was involved. This task was performed in both silent and noisy conditions. To evaluate the cerebral activity of volunteers during the development of the test, measurement of spontaneous activity (electroencephalogram) was developed. The results show significant decreases in both beta and theta frequency bands under background noise exposure. Since attentional improvement is related to an increment on amplitude of both beta and theta bands, it is suggested that decreases on amplitude of these frequency bands could directly be related to a lack of attention caused by the exposure to background noise.

Forced synchronization of autonomous dynamical Boolean networks.

We present the design of an autonomous time-delay Boolean network realized with readily available electronic components. Through simulations and experiments that account for the detailed nonlinear response of each circuit element, we demonstrate that a network with five Boolean nodes displays complex behavior. Furthermore, we show that the dynamics of two identical networks display near-instantaneous synchronization to a periodic state when forced by a common periodic Boolean signal. A theoretical analysis of the network reveals the conditions under which complex behavior is expected in an individual network and the occurrence of synchronization in the forced networks. This research will enable future experiments on autonomous time-delay networks using readily available electronic components with dynamics on a slow enough time-scale so that inexpensive data collection systems can faithfully record the dynamics.

The development of anisotropic behaviours of 3T3 fibroblasts on microgrooved patterns.

3T3 fibroblasts cultured on microgrooved polydimethylsiloxane (PDMS) surfaces of two different widths (25 µm and 55 µm) were individually tracked using confocal microscopy with a novel live-cell staining technique over several hours without noticeable cytotoxic effects. By quantifying the cell morphology, orientation, and migration over time, we identified the timescale (about 2-4 h after seeding) over which cell behaviours transitioned from isotropy to anisotropy, where the preference is in the direction parallel to the pattern. The development of anisotropy occurred more rapidly and distinctly when a narrower ridge width was used, suggesting that it is the ridge width that imposed a physical barrier on the cells' morphology and motility. Furthermore, while we found a weak but statistically significant correlation between cell orientation and morphology on the single-cell level, there is a lack of correlation on the same level between cell orientation and migratory direction. This suggests that while morphology and migration are affected anisotropically by topographical patterns in a similar way, the underlying processes giving rise to the anisotropy is slightly different in the two cases.

Development of a 3D human in vitro skin co-culture model for detecting irritants in real-time.

Tissue engineered materials for clinical purposes have led to the development of in vitro models as alternatives to animal testing. The aim of this study was to understand the paracrine interactions arising between keratinocytes and fibroblasts for detecting and discriminating between an irritant-induced inflammatory reaction and cytotoxicity. We used two irritants [sodium dodecyl sulphate (SDS) and potassium diformate (Formi] at sub-toxic concentrations and studied interleukin-1 alpha (IL-1 alpha) release from human keratinocytes and activation of NF-kappaB in human fibroblasts. NF-kappaB activation in fibroblast 2D cultures required soluble factors released by prior incubation of keratinocytes with either SDS or Formi. Neither cell type responded directly to either agent, confirming a paracrine mechanism. Fibroblasts were then cultured in 3D microfiber scaffolds and transfected with an NF-kappaB reporter construct linked to GFP. Findings for 3D cultures were similar to those in 2D in that soluble factors released by prior incubation of keratinocytes with SDS or Formi was required for NF-kappaB activation in fibroblasts. Similarly, direct incubation with either agent did not directly activate NF-kappaB. A technical advantage of using transfected cells in 3D was an ability to detect NF-kappaB activation in live fibroblasts. To confirm paracrine signaling a twofold increase in IL-1 alpha was measured in keratinocyte-conditioned medium after incubation with SDS or Formi, which correlated with fibroblast NF-kappaB activity. In summary, this work has value for developing 3D tissue engineered co-culture models for the in vitro testing of irritant chemicals at sub-toxic concentrations, as an alternative to in vivo models.

Forced synchronization of a self-sustained chaotic oscillator.

This work presents a forced synchronization phenomenon like the asymptotic correlated behavior between chaotic oscillators forced by an external signal. Different kinds of forced synchronization are presented and given a theoretical justification explaining why it is possible to find some of them. Numerical results are presented for different cases such as antisymmetric, lag, phase, and identical forced synchronization.

Concurrencia de síndromes paraneoplásicos neurológicos, en paciente afecta de cáncer de mama y metástasis cerebral: revisión de la literatura / Concurrence of neurologic paraneroplastic syndromes in a woman with brain metastatic breast cancer: review of the literature

Los Síndromes paraneoplásicos neurológicos sonentidades complejas, de difícil diagnóstico, y quepueden afectar a cualquier parte del sistemanervioso. El descubrimiento de nuevos antígenosonconeuronales y su relación con las alteracionesinmunológicas asociadas están ayudando a undiagnóstico precoz. La asociación con el carcinomade mama es infrecuente. Presentamos el caso de unapaciente de 62 años, diagnosticada de carcinoma demama izquierda, mastectomizada y tratada conquimioterapia adyuvante. Presentó recidiva, conmetástasis cerebelosa resecada quirúrgicamente ytratada con radioterapia. Se complicó con cuadromiasteniforme de tipo Lambert-Eaton, disfunciónautonómica y posterior encefalítis límbica con comairreversible. La aplicación de los nuevos criteriosdiagnósticos, los descubrimientos moleculares y larealización de ensayos clínicos terapeúticos,podrían mejorar las expectativas en estas pacientes

Neurological paraneoplastic syndromes arecomplex entities of difficult diagnosis. They canlocate in any part of the nervous system producingimportant neurological dysfunctions. The discoveryof new specific anti-neuronal antibodies and theirrelation with the associated immunologicalalterations help to make an early diagnosis.Association with breast cancer is not frequent. Wepresent the case of a 62-year old patient with leftbreast carcinoma that had been treated bymastectomy and adjuvant chemotherapy one yearbefore. She relapsed with cerebellum metastasesand was treated by surgery and radiotherapy. Thepicture was complicated with a Lambert-Eaton-likemyasthenic syndrome, neuroplastic sensoryneuronopathy, limbic encephalitis and irreversiblecoma. The application of new diagnostic criteria,the molecular discoveries and the performance oftherapeutic clinical trials could better the lifeexpectancy of these patients

A single-nucleotide polymorphism in the gene encoding lymphoid protein tyrosine phosphatase (PTPN22) confers susceptibility to generalised vitiligo.

Vitiligo is an acquired hypomelanotic skin disorder resulting from the loss of functional melanocytes from the cutaneous epidermis and autoimmunity has been suggested to play a part in its pathogenesis. Recently, the missense R620W polymorphism in the PTPN22 gene, which encodes lymphoid protein tyrosine phosphatase (LYP), has been associated with susceptibility to autoimmune disorders. The objective of this study was to ascertain if the disease-associated 1858T allele was also associated with generalised (nonsegmental) vitiligo and so the frequencies of the PTPN22 1858C/T alleles were investigated in 165 English patients with generalised vitiligo and 304 ethnically matched control subjects. The results indicated that the 1858T allele was significantly over-represented in the vitiligo patient group compared with the control cohort. Of 330 vitiligo alleles, 48 (14.5%) encoded the Trp620 variant compared to 52 of 608 (8.6%) control alleles (P=0.006; odds ratio=1.82, 95% confidence interval=1.17-2.82). The results indicate that the LYP missense R620W polymorphism may have an influence on the development of generalised vitiligo and provide further evidence for autoimmunity as an aetiological factor with respect to this disease.

HER2 y carcinoma de próstata: ¿una relación de utilidad clínica? / HER2 and prostate carcinoma: is there any relation with clinical utility?

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[Prognostic factors of bacteremia: prospective study]. / Factores pronósticos de la bacteriemia: estudio prospectivo.

BACKGROUND: To identify the epidemiology and risk factors with influence in the outcome and mortality of a series of bacteriemic patients. MATERIAL AND METHODS: A prospective study of bloodstream infections with clinical significance detected in a secondary hospital of 650 beds over period from May 1998 to May 1999. The true bacteriemia was defined in basis to the criteria both the physician and microbiologist. A total of 16 variables were defined and categorized such as clinical-epidemiologic, intrinsic risk factor, extrinsic risk factor, outcome and survival. We used SPSS statistical package: For cuantitative variables we carried out with the mean with confidence interval of 95%, for cualitative variables: number and %. Univariate analysis of the results was carried out with the X2 test and t Student, the survival was expressed with Kaplan Meyer graphics and the logistic regression model. RESULTS: A total of 320 positive blood cultures were studied but only 272 blood cultures were considered true bacteriemia in 259 patients. The calculated incidence of significant episodes of bacteriemia per 1000 admissions/year was 13. The overall mortality was 22% whereas death attributable to bacteriemia was 16%. The mean age was 66.9 years (IC 95% 65-69), 59% episodes occurred in men. The 78% episodes occurred in patients hospitalized in medical services. 52% episodes were of nosocomial infection and 48% of community acquired infection. According to the severity of the underlying disease, 15% had fatal diseases and 35% episodes occurred in patients without underlying disease. According to the univariant analysis, the variables which where significantly associated with greater risk death were: etiology (fungus), septic shock, the inadequate antibiotic therapy, presence of extrinsic factors (central intravenous catheter, performance of invasive procedures, previous antimicrobial therapy) and the hospital stay of less than 10 days. According to the multivariable analysis showed that the factors remaining independent predictors of mortality were: septic shock (p < 0.0001, OR: 8), inadequate antimicrobial therapy (p < 0.005, OR: 6.7), existence of two or more extrinsic risk factors (p < 0.04). CONCLUSIONS: The presence of septic shock was the most important variable which influenced in the mortality in our serie, together with inappropriate antimicrobian therapy and the association of various extrinsic risk factors. These variables could be modified partly, for this reason the aggressive hemodynamic control and the early and appropriate antibiotic therapy would be the support of the successful bacteriemia management.

Factores pronóstico de la bacterimia: estudio prospectivo / Pronostic factors of the bloodstream infections: prospective study

Objetivo : Conocer la epidemiología e identificar los factores de riesgo que influyeron en la mortalidad de nuestros pacientes con bacteriemia.Material y métodos: Estudio prospectivo de las bacteriemias significativas detectadas en un hospital secundario de 650 camas en el período de mayo de 1998 a mayo de 1999. La catalogación como significativa se realizó de acuerdo con el criterio del clínico y microbiólogo implicados.Se analizaron 16 variables categorizadas como clínico-epidemiológicas, factores de riesgo intrínseco y extrínseco, evolución y supervivencia. El análisis estadístico se hizo en base al programa informático SPSS; para variables cuantitativas se utilizó la media con IC del 95 por ciento, y para las variables cualitativas: nº y por ciento. El análisis bivariante se realizó con t Student y X2; la supervivencia se expresó con gráficas de Kaplan-Meyer y el índice de regresión logística de Cox.Resultados: Se analizaron 320 hemocultivos que tras la valoración del clínico se redujeron a 272 episodios de bacteriemia clínicamente significativa en 259 pacientes, con una incidencia de 13 casos/1000 admisiones/año. La mortalidad global fue del 22 por ciento, mientras la directamente relacionada con la bacteriemia fue del 16 por ciento. La edad media fue 66,9 años (IC 95 por ciento: 65-69) con predominio de varones(59 por ciento), localizándose en el área médica hasta un 78 por ciento de los casos, siendo de origen nosocomial el 52 por ciento y comunitario el 48 por ciento. Un 15 por ciento de los casos eran portadores de enfermedad fatal y hasta un 35 por ciento carecían de enfermedad de base.Según el análisis univariante se asoció con mayor de riesgo de muerte (p<0,05): la etiología (fungemias), la presencia de shock, adecuación de tratamiento, existencia de factores extrínsecos (catéter central, antibioticoterapia previa y procedimientos invasivos) y estancia hospitalaria menor de 10 días. Con el análisis multivariante sólo se identificaron como factores pronósticos independientes: Shock séptico (p<0,0001 con RR. 8), adecuación de tratamiento (p<0,001 con RR 6,67), presencia de más de 2 factores extrínsecos (p<0,04).Conclusiones: La aparición de shock al diagnóstico fue la variable que más influyó en la mortalidad de nuestros pacientes, seguida de la inadecuación del tratamiento antibiótico y la existencia de factores de riesgo extrínsecos. Estas variables modificables en cierto grado obligan a incidir sobre la necesidad de un control hemodinámico agresivo y el establecimiento de un tratamiento antibiótico precoz adecuado (AU)

Contributions of Camillo Golgi to renal histology and embryology.

Camillo Golgi was awarded the Nobel prize in 1906 for his studies on the fine anatomy of the central nervous system. His wide present popularity depends on his discovery of the cell apparatus, the tendon mechanoreceptor and the tactile corpuscles of the fingertips that are named after him. However, Golgi also made important contributions to nephrology. In 1882, he published novel observations on the mechanism of renal hypertrophy, which he understood to be due to renal cell proliferation. Two years later, he described tubular cell mitoses in the kidney of a patient with tubulointerstitial nephritis, which he interpreted as an essential part of the repair process. His most important findings, published in 1889, were obtained by studying the microscopic anatomy of the kidney with an original technique that allowed the isolation of whole intact nephrons. He discovered that the ascending limb of Henle's loop always returned to the glomerulus from which the tubule originated, and he realized that the early distal tubule passed between the glomerular arterioles. In addition, applying the same method to dissect nephrons in progressive phases of development, he identified exactly what tubular segments originated from the various parts of the metanephric early S-shaped structure.

Involvement of interleukin-6 in the biology and metastatic activity of B16F10 melanoma cells.

In previous studies, we demonstrated the presence of the interleukin-2 (IL-2) signalling system in B16F10 murine melanoma and observed that in vitro treatment of B16F10 cells with IL-2, enhanced metastasis. To further understand the role played by interleukins in melanoma, we examined the effect of IL-6 on the metastatic activity and properties of B16 melanoma cells. We observed that B16F10 cells, cultured in the presence of IL-6, showed a clear increase in their metastatic ability, both in the liver and in the lungs. Neither cell proliferation nor in vitro colony formation were affected by IL-6; however, the expression of CD44 and VLA-4 increased. The IL-6 gene was expressed in B16F10 cells as shown by RT-PCR. A slight induction of IL-6 mRNA expression by IL-2 was observed, but not after treatment with IL-1beta or IL-6. Nevertheless, no soluble IL-6 could be detected in cell supernatants even after treatment with IL-2. Finally, we tested the effect of IL-1beta, IL-6 and IL-2 on the expression of the IL-2 receptor (IL-2R). IL-1beta turned out to be the strongest inducer of IL-2R expression in B16F10 cells. Altogether, these data confirm the involvement of interleukins in the biology and metastatic activity of melanoma.

The famous case of rheumatic hematuria described by Giammatteo Ferrari da Grado, professor at the University of Pavia (1432-1472).

Giammatteo Ferrari da Grado was an influential professor and teacher of medicine at the University of Pavia in middle of the 15th century. He authored three important texts, among which is the Consilia, a collection of cases he visited and/or consulted. Among these, Ferrari describes a case of rheumatic hematuria in an eminent patient, Gaston de Foix, prince of Navarre. Following a precise description of the symptoms, he makes a complex pathogenic interpretation based on the theory of humors current at the time, and goes on to offer his patient a generous spectrum of herbal, hygienic and dietetic remedies.