Reticular influences on primary and augmenting responses in the somatosensory cortex

The effects of brief, conditioning trains of high-frequency pulses to the midbrain reticular formation (RF) on primary and augmenting responses of somatosensory (SI) cortex were investigated. Testing stimulation was applied to the ventrobasal (VB) thalamus or to the white matter (WM) beneath SI in VB-lesioned animals. The RF-elicited EEG activation was associated with increased firing rates of SI neurons, enhanced probability of early synaptic discharges to VB or WM stimuli, and significantly reduced duration of the suppressed firing period following an afferent VB or WM volley. The diminished latency of the postinhibitory rebound under RF stimulation had the consequence that, within 10/sec shock-train, the second stimulus was delivered following completion of the rebound component and, instead of an augmented potential, generated a field response of primary-type. The dependence of the RF-induced change in augmenting potentials upon the sharpening effect exerted on the preceding inhibitory-rebound sequence was corroborated by analyzing the RF influence on neurons with different time-course of recovery from inhibition. The replacement of augmenting potentials by primary responses under RF stimulation is advanced as the mechanism behind the obliteration of spontaneously developing 'type I' spindle-waves during EEG arousal. The demonstration of RF influences on SI responses to WM stimulation in VB-lesioned animals points out the cortical level of the effects. The reticulo-thalamo-cortical pathways underlying these influences are discussed.     

Synchronous gastric adenocarcinoma and carcinoid

We report the rare case of a 68-year-old man who had two separate and histologically dissimilar gastric tumors: a poorly differentiated adenocarcinoma and a carcinoid. The latter tumor showed argyrophilic granules (Grimelius technique) and positivity for chromogranin A and neuron-specific enolase stains, confirming the neuroendocrine nature of the neoplasia. The literature concerning this subject is reviewed.     

Why human pemphigoid autoantibodies do not trigger disease by the passive transfer into mice?

The recapitulation of disease features in animals by the transfer of patient autoantibodies has been used to demonstrate the autoimmune nature of several diseases. Failure of disease induction by the passive transfer of autoantibodies has been assigned to a limited cross-reactivity of the autoantibodies with the murine tissue. However, the possibility that the passively transferred "inflammatory" patient autoantibodies may not be able to unfold their pathogenic potential due to restricted Fc-dependent effector functions has not yet been systematically explored. In this study we analyze the interaction of patients' autoantibodies with murine complement and granulocytes. Bullous pemphigoid is a blistering disease associated with autoantibodies, which are thought to induce subepidermal blistering by activating complement and granulocytes. The passive transfer of patients autoantibodies failed to induce skin blistering in wild type mice. The cross-reactivity of pemphigoid autoantibodies with murine antigens was analyzed in silico, ex vivo and by the passive transfer of IgG in vivo. Complement-fixing ability of patients' autoantibodies was evaluated by complement-binding test. Granulocyte activation was assessed by reactive oxygen species production assay and the cryosection model. We have found that although pemphigoid autoantibodies bound to murine skin in vitro and in vivo, they showed a lower capacity to fix murine complement and a reduced ability to activate murine granulocytes when compared with human complement and cells, respectively. These results indicate that for disease models using the passive transfer of patient autoantibodies, their interaction with the innate factors of the host should be optimized to match the human situation.     

How efficient is acoustic radiation force impulse elastography for the evaluation of liver stiffness?

Background

In chronic liver diseases, a correct estimation of the severity of liver fibrosis is important for recommendations regarding the treatment. Nowadays, evaluation of fibrosis is done by noninvasive methods such as biochemical scores and transient elastography instead of liver biopsy. The lack of sensitivity to detect fibrosis, because of its heterogeneity is a drawback of liver biopsy (LB).

Objectives

To compare transient elastography (TE) and acoustic radiation force impulse (ARFI) for the evaluation of liver stiffness (LS), against percutaneous LB.

Patients and Methods

Our study comprised of 223 subjects; 52 without fibrosis (38 volunteers and 14 patients with F0 on LB), 36 with F1, 40 with F2, 26 with F3 and 69 with liver cirrhosis (46 with LB and 23 with signs of cirrhosis). For each patient we performed in the same session 10 TE and 5 ARFI measurements. The median values were calculated.

Results

A strong linear correlation (Spearman rho = 0.870) was found between TE and fibrosis (P < 0.0001); there was also a weaker correlation between ARFI and fibrosis (Spearman rho = 0.646; P < 0.0001). TE measurements were also correlated with ARFI measurements (Spearman rho = 0.733, P < 0.0001). The best test for predicting significant fibrosis (F ≥ 2) was TE with a cut-off value of 7.1 kPa (AUROC 0.953). For ARFI, the cut-off value was 1.27 m/s-area under ROC curve (AUROC): 0.890, sensitivity (Se) of 88.7%, specificity (Sp) of 67.5%, positive predictive value (PPV) of 64.5%, and negative predictive value (NPV) of 90% (P = 0.0044). For predicting cirrhosis (F = 4), the optimum cut-off values were 14.4 kPa for TE (AUROC: 0.985, Se: 95.6%, Sp: 94.7%, PPV: 89.2%, NPV: 98%) and 1.7 m/s for ARFI (AUROC: 0.931, Se: 93%, Sp: 86.7%, PPV: 73.6%, NPV: 96.9%) (P = 0.0102).

Conclusions

LS evaluation by means of ARFI is not superior to TE for the assessment of liver fibrosis. ARFI is an accurate test for the diagnosis of cirrhosis.     

Neurogenic tumors of the posterior mediastinum

The posterior mediastinum is the potential space along each side of the vertebral column and adjacent proximal portions of the ribs--the paravertebral sulci. From the posterior mediastinal tumors, the most commonly encountered are the neurogenic tumors (75%), the remaining 25% are represented by a heterogenous group of rare tumors including teratoma, lymphoma, sarcoma and other lesions arising outside the mediastinum and projecting into the posterior compartment. Surgical excision, by thoracotomy or miniinvasive techniques, is the first line of treatment in the posterior mediastinal tumors. Tumors with extension into the spinal canal (dumbbell tumors), accounting for nearly 10% of the posterior mediastinal tumors, require a multidisciplinary approach: thoracic surgeon and neurosurgeon. We present the experience of the "Carol Davila" University of Medicine and Pharmacy Thoracic Surgery Clinic in the surgery of neurogenic posterior mediastinal tumors throughout a 9 year period (2001 - 2010). 42 cases admitted and operated in this period are being analysed.     

Detection of exon deletions within an entire gene (CFTR) by relative quantification on the LightCycler

BACKGROUND: Cystic fibrosis (CF) is associated with at least 1 pathogen point sequence variant on each CFTR allele. Some symptomatic patients, however, have only 1 detectable pathogen sequence variant and carry, on the other allele, a large deletion that is not detected by conventional screening methods. METHODS: For relative quantitative real-time PCR detection of large deletions in the CFTR gene, we designed DNA-specific primers for each exon of the gene and primers for a reference gene (beta2-microglobulin). For PCR we used a LightCycler system (Roche) and calculated the gene-dosage ratio of CFTR to beta2-microglobulin. We tested the method by screening all 27 exons in 3 healthy individuals and 2 patients with only 1 pathogen sequence variant. We then performed specific deletion screenings in 10 CF patients with known large deletions and a blinded analysis in which we screened 24 individuals for large deletions by testing 8 of 27 exons. RESULTS: None of the ratios for control samples were false positive (for deletions or duplications); moreover, for all samples from patients with known large deletions, the calculated ratios for deleted exons were close to 0.5. In addition, the results from the blinded analysis demonstrated that our method can also be used for the screening of single individuals. CONCLUSIONS: The LightCycler assay allows reliable and rapid screening for large deletions in the CFTR gene and detects the copy number of all 27 exons.     

alpha-Melanocyte-stimulating hormone is neuroprotective in rat global cerebral ischemia

The aim of the study was to investigate the effects of alpha-melanocyte-stimulating hormone (alpha-MSH), a tridecapeptide derived from proopiomelanocortin (POMC), on the neurodegeneration following global cerebral ischemia and reperfusion in the rat. The biological activities of alpha-MSH include inhibition of inflammatory responses and anti-pyretic effects. Male Sprague-Dawley rats were subjected to four-vessel occlusion (4-VO) global cerebral ischemia followed by reperfusion, and treated with alpha-MSH (intraperitoneally, i.p.) at 30 min, and 24, 48, 72 and 96 h post-ischemia. Stereological quantification of the pyramidal cells in the CA1 area of the hippocampus showed that the number of viable neurons in ischemic rats was 96,945+/-18,610 (means+/-SD) as compared to 183,156+/-49,935 in sham-operated rats (P<0.05). The number of viable neurons after treatment of ischemic rats with alpha-MSH was 162,829+/-34,757, i.e. significantly different from the number of viable neurons in ischemic rats injected with saline (P<0.01). Astrocyte proliferation due to the ischemic insult was markedly reduced by the treatment with alpha-MSH, and the loss in body weight was reduced by alpha-MSH. In conclusion, post-ischemic administration of alpha-MSH was found to provide neuroprotection in the CA1 pyramidal cell layer in the hippocampus, concomitant with a reduction in glial activation, indicating that alpha-MSH or mimetics thereof may have a potential in the treatment of stroke or other neurodegenerative diseases. Further studies will be required to define the post-ischemic time window for administration of alpha-MSH.     

Accurate Prediction of Collapse Temperature using Optical Coherence Tomography-Based Freeze-Drying Microscopy

The objective of this study was to assess the feasibility of developing and applying a laboratory tool that can provide three-dimensional product structural information during freeze-drying and which can accurately characterize the collapse temperature (T_c) of pharmaceutical formulations designed for freeze-drying. A single-vial freeze dryer coupled with optical coherence tomography freeze-drying microscopy (OCT–FDM) was developed to investigate the structure and T_c of formulations in pharmaceutically relevant products containers (i.e., freeze-drying in vials). OCT–FDM was used to measure the T_c and eutectic melt of three formulations in freeze-drying vials. The T_c as measured by OCT–FDM was found to be predictive of freeze-drying with a batch of vials in a conventional laboratory freeze dryer. The freeze-drying cycles developed using OCT–FDM data, as compared with traditional light transmission freeze-drying microscopy (LT-FDM), resulted in a significant reduction in primary drying time, which could result in a substantial reduction of manufacturing costs while maintaining product quality. OCT–FDM provides quantitative data to justify freeze-drying at temperatures higher than the T_c measured by LT-FDM and provides a reliable upper limit to setting a product temperature in primary drying.