A simple method for calculating the depth of EEG sources using minimum norm estimates (MNE)

Neural source localization using electroencephalographic data is usually performed using either dipolar models or minimum norm based techniques. While the former demands a priori information about the number of active sources and is particularly suitable for generators, which occupy small pieces of cortical tissue, the major drawbacks of the second approach are its dependence on the uncorrelated noise, and its tendency to localize the sources at the surface. In this paper, a simple mathematical procedure, based on the behavior of the dispersion of the minimum norm solutions, is introduced, in order to estimate the depth of the sources. The correct position of the active generators is obtained using successively deeper surfaces instead of the application of a regularization matrix, as is commonly described in the bibliography. The evaluation of this technique is performed using single and double dipolar simulated generators and two different models for the head: spherical and realistic. The results yield a mean accuracy of about 10 mm for the most disadvantageous situations studied and thus, this method seems to be very promising to handle the depth of the neural generators.     

Anti-hyperalgesic effects of two sphingosine derivatives in different acute and chronic models of hyperalgesia in mice

Background

The study evaluated the effects of two sphingosine derivatives N-(2-tert-butoxycarbamylhexadecyl)glutaramide (AA) and N-(1-benzyloxyhexadec-2-yl)glutaramide (OA) in different models of hypersensitivity in mice.

Heat dissipation after nonanatomical lung resection using a laser is mainly due to emission to the environment: an experimental ex vivo study

Laser-directed resection of lung metastases is performed more frequently in recent years. The energy-loaded laser rays heat up the lung tissue, considerably. It is still unclear which mechanism is more important for tissue heat dissipation: the lung perfusion or the tissue emission. Therefore, we created a special experimental model to investigate the spontaneous heat dissipation after nonanatomical lung resection using a diode-pumped laser with a high output power. Experiments were conducted on paracardiac pig lung lobes (n?=?12) freshly dissected at the slaughterhouse. Nonanatomical resection of lung parenchyma was performed without lobe perfusion in group 1 (n?=?6), while group 2 (n?=?6) was perfused at a physiological pressure of 25 cm H₂O at 37 °C with saline via the pulmonary artery. For this, we used a diode-pumped neodymium-doped yttrium aluminum garnet (Nd:YAG) LIMAX® 120 laser (Gebrüder Martin GmbH & Co. KG, Tuttlingen, Germany) with a wavelength of 1,318 nm and a power output of 100 W. Immediately after completing laser resection, the lungs were monitored with an infrared camera (Type IC 120LV; Trotec, Heinsberg, Germany) while allowed to cool down. The resection surface temperature was taken at 10-s intervals and documented in a freeze-frame until a temperature of 37 °C had been reached. The temperature drop per time unit was analyzed in both groups. Immediately after laser resection, the temperature at the lung surface was 84.33?±?8.08 °C in group 1 and 76.75?±?5.33 °C in group 2 (p?=?0.29). Group 1 attained the final temperature of 37 °C after 182.95?±?53.76 s, and group 2 after 121.70?±?16.02 s (p?=?0.01). The temperature drop occurred exponentially in both groups. We calculated both groups’ decays using nonlinear regression, which revealed nearly identical courses. The mean time of tissue temperature of >42 °C, as a surrogate marker for tissue damage, was 97.14?±?26.90 s in group 1 and 65.00?±?13.78 s in group 2 (p?=?0.02). Heat emission to the environment surpasses heat reduction via perfusion in nonanatomically laser-resected lung lobes. In developing a cooling strategy, a topical cooling method would be promising.     

Identification of HPV genotypes causing cervical precancer using tissue-based genotyping

Identification of high-risk human papillomavirus genotypes causing cervical precancer is crucial for informing HPV vaccine development and efficacy studies, and for determining which types to include in next-generation genotyping assays. Co-occurrence of hrHPV infections is common and complicates carcinogenicity assessment; accurate attribution requires tissue-based genotyping of precancers. We included all women with cervical intraepithelial neoplasia Grade 2 or worse (CIN2+) from the Biopsy Study, an observational study of 690 women enrolled between 2009 and 2012 at the University of Oklahoma. Tissue-based genotyping, including whole tissue sections (WTS) and laser-capture microdissection (LCM), was performed on all precancers with multiple hrHPV infections detected in cytology, totaling over 1,800 HPV genotyping assays. Genotype attribution was compared to hierarchical and proportional hrHPV-type attribution models. Of 276 women with CIN2+, 122 (44.2%) had multiple hrHPV genotypes in cytology. Of 114 women with genotyping data, 94 had one or more hrHPV detected in tissue. Seventy-one women (75.5%) had a single causal hrHPV genotype, while 23 women had multiple hrHPV genotypes causing CIN2+. Ten women had multiple causal infections in a single biopsy, contrary to the previous notion that each lesion is caused by a single type only. While HPV16 was the predominant causal hrHPV genotype using all approaches, the hierarchical model overattributed HPV16, whereas other causal hrHPV genotypes, particularly HPV18 and HPV35, were underattributed. Understanding true causal genotypes is important for the evaluation of vaccine efficacy, to estimate the extent of unmasking, and for type-specific risk assessment in screening and management.     

The Role of GJD2(Cx36) in Refractive Error Development

Refractive errors are common eye disorders characterized by a mismatch between the focal power of the eye and its axial length. An increased axial length is a common cause of the refractive error myopia (nearsightedness). The substantial increase in myopia prevalence over the last decades has raised public health concerns because myopia can lead to severe ocular complications later in life. Genomewide association studies (GWAS) have made considerable contributions to the understanding of the genetic architecture of refractive errors. Among the hundreds of genetic variants identified, common variants near the gap junction delta-2 (GJD2) gene have consistently been reported as one of the top hits. GJD2 encodes the connexin 36 (Cx36) protein, which forms gap junction channels and is highly expressed in the neural retina. In this review, we provide current evidence that links GJD2(Cx36) to the development of myopia. We summarize the gap junctional communication in the eye and the specific role of GJD2(Cx36) in retinal processing of visual signals. Finally, we discuss the pathways involving dopamine and gap junction phosphorylation and coupling as potential mechanisms that may explain the role of GJD2(Cx36) in refractive error development.     

Modulation of in vitro eosinophil progenitors by hydrocortisone: role of accessory cells and interleukins

The growth of human eosinophil progenitors (CFU-Eo) and the modulation of growth by hydrocortisone were studied as functions of the presence of lymphocytes and monocytes in marrow cells under study; and the source of colony-stimulating factors, specifically, media conditioned by macrophage-like cell line, GCT; phytohemagglutinin-stimulated mononuclear cells (PHA-LCM); or the T cell line, MO. CFU-Eo growth was greatest in marrow containing accessory cells as compared to marrow depleted of accessory cells; and in marrow treated with phytohemagglutinin-stimulated leukocyte conditioned media (PHA-LCM) or MO (T cell line)-conditioned medium (MO-CM) as compared with GCT cell- conditioned medium (GCT-CM). Hydrocortisone reproducibly inhibited eosinophil progenitor growth in unfractionated marrow stimulated by GCT- CM. This effect was abrogated by admixing irradiated mononuclear cells or T lymphocytes with the target marrow or by adding interleukin 1 or interleukin 2 (IL-1, IL-2). Inhibition by hydrocortisone did not occur when monocyte and T lymphocyte depleted marrow was studied. Unlike GCT- CM, MO-CM and PHA-LCM stimulated equal proportions of eosinophil progenitors in nondepleted and accessory cell-depleted marrow and demonstrated less hydrocortisone inhibition. However, both GCT-CM and PHA-LCM produced in the presence of hydrocortisone stimulated significantly fewer CFU-Eos in both unfractionated and accessory cell- depleted marrow target populations. These results indicate that the growth of CFU-Eo and inhibition of growth by hydrocortisone is a direct function of a monocyte-T cell interaction and probably is mediated through effects on the production/release of eosinophil colony stimulating factor (Eo-CSF).