Guiding the study of brain dynamics by using first-person data: Synchrony patterns correlate with ongoing conscious states during a simple visual task

Even during well-calibrated cognitive tasks, successive brain responses to repeated identical stimulations are highly variable. The source of this variability is believed to reside mainly in fluctuations of the subject's cognitive "context" defined by his/her attentive state, spontaneous thought process, strategy to carry out the task, and so on...As these factors are hard to manipulate precisely, they are usually not controlled, and the variability is discarded by averaging techniques. We combined first-person data and the analysis of neural processes to reduce such noise. We presented the subjects with a three-dimensional illusion and recorded their electrical brain activity and their own report about their cognitive context. Trials were clustered according to these first-person data, and separate dynamical analyses were conducted for each cluster. We found that (i) characteristic patterns of endogenous synchrony appeared in frontal electrodes before stimulation. These patterns depended on the degree of preparation and the immediacy of perception as verbally reported. (ii) These patterns were stable for several recordings. (iii) Preparatory states modulate both the behavioral performance and the evoked and induced synchronous patterns that follow. (iv) These results indicated that first-person data can be used to detect and interpret neural processes.     

Minimally invasive video thoracoscopic correction of pectus excavatum

Pectus excavatum, the most common congenital deformity of the chest wall, has esthetic, psychological and social repercussions as well as a slight impact on pulmonary function. Treatment is surgical and is carried out for esthetic purposes in most cases. The most commonly applied surgical technique is based on the one originally described by Ravitch: sub-perichondrial, bilateral chondrectomy and sternal osteotomy. In 1997, however. Nuss described a minimally invasive approach to correction by means of a support bar. Our objective was to perform minimally invasive correction of pectus excavatum using a substernal extrapleural approach guided by video-assisted thoracoscopy. We treated three patients over 15 years of age without surgical complications. In all three cases, the minimally invasive technique corrected the pectus excavatum with excellent esthetic results. Both the path of insertion and duration were shorter with the described approach than with traditional surgery. Video images facilitated extrapleural insertion of the bar and minimized complications.     

Bronchobiliary fistulae between a liver hydatid cyst and the middle lobe of the right lung

We report a case of bronchobiliary fistula between a liver hydatid cyst and the middle lobe of the right lung. It is also reviewed the etiology, pathogenesis, clinical features, diagnosis and treatment of bronchobiliary fistulas.     

Low-pressure laparoscopy may ameliorate intracranial hypertension and renal hypoperfusion

BACKGROUND: Increased abdominal pressure is associated with elevations in the intracranial pressure (ICP) and impaired renal function. These adverse effects are potentially important in clinical situations such as severe abdominal trauma and laparoscopic donor nephrectomy. It was hypothesized that the secondary elevation of ICP leads to release of vasoconstrictors, which may affect renal function by decreasing the renal blood flow (RBF). We investigated the effect of laparoscopy on ICP and renal blood flow in a porcine model. MATERIALS AND METHODS: The abdominal pressure of swine (N = 5; 20-25 kg) was gradually increased from baseline to 5, 15, and 25 mm Hg by insufflation of nitrogen into the abdominal cavity. The ICP was measured using a Camino monitor, and RBF was simultaneously measured using a Transonic Doppler probe placed on the renal artery. Results were analyzed using repeated measures ANOVA and the paired t-test. RESULTS: No significant change from baseline was observed in ICP and RBF when the abdominal pressure was 5 mm Hg. However, both ICP and RBF were affected by increasing the abdominal pressure to 15 and 25 mm Hg (P = 0.035 and 0.04 for ICP and P = 0.074 and 0.034 for RBF, respectively). CONCLUSIONS: Low-pressure laparoscopy may reduce the adverse effects of pneumoperitoneum on ICP and RBF. It may be advisable to use low pressures in laparoscopic surgery, especially when changes in ICP or renal perfusion may have significant clinical implications.     

Expression of CD44s and CD44 splice variants in human melanoma.

The ability of tumor cells to adhere and detach from extracellular matrix and endothelial cells, is a crucial step in the metastatic process and may alter the clinical prognosis of some human tumors such as melanomas. CD44, the major cell surface receptor for hyaluronate, has been implicated in cell adhesion and in tumor progression. We studied the expression of standard CD44 molecule (CD44s) and its variants v3 and v6 in 57 human primary melanoma biopsies, without previous treatment. We analyzed the association between CD44 expression and the principal clinicopathological features, including survival. Fifty-six of 57 tumors expressed CD44s, associated to the cytoplasmic membrane. No expression of CD44v3 or CD44v6 was detected. No association between CD44s expression and prognostic factors such as tumor thickness, growth type, stage or anatomic site of the lesion was found. However, a positive correlation between CD44s expression and Clark level (Spearman, p<0.001) was found. While only 33.3% of melanomas Clark I + II showed high expression of CD44s (more than 50% of positive cells), 82.6% of melanomas Clark IV + V did so. Kaplan-Meier analysis revelead that patients whose melanomas had high expression of CD44s showed a reduced relapse free survival (RFS) rate, though without statistical significance. No difference between the level of CD44 expression and overall survival (OS) was found. We conclude that melanomas only expressed CD44s, and that its level was associated with Clark's stage. CD44s seems not to be useful as a tumor marker, because it does not predict either RFS or OS.     

Regional lymphadenopathy in cat-scratch disease: ultrasonographic findings

Background. Cat-scratch disease (CSD) is considered to be an emerging disease worldwide and is caused by Bartonella henselae, a gram-negative bacterium introduced by a scratch or bite of a cat. The most common clinical manifestation is regional lymphadenopathy, but clinical recognition may be difficult, as atypical manifestations may occur. The diagnosis is confirmed with serologic testing and histology is rarely needed. This paper is based on our experience with the use of ultrasonography in the diagnosis of CSD.¶Objective. The aim of this study was to describe the sonographic and color Doppler appearances of regional lymphadenopathy in CSD, as this has not widely reported in the literature. ¶Materials and methods. Forty-seven patients (average 9.4 years) were included who all had serologically and/or histologically proven CSD and had been studied using US early in the clinical course. All had a positive history of exposure to cats and exhibited regional lymphadenopathy.¶Results. US showed large hypoechoic adenopathy with some transmission enhancement and high vascularization on color-flow Doppler imaging. In 30 patients, abdominal US was also performed and splenic and/or hepatic granulomata were found in 10.¶Conclusions. In our experience, sonography and especially color-Doppler and power-Doppler sonography was helpful in the diagnosis of CSD. We believe it should be used in the initial study of children with regional lymphadenopathy, and serologic testing should be performed when CSD is suspected.