Glutamate exocytosis from astrocytes controls synaptic strength

The release of transmitters from glia influences synaptic functions. The modalities and physiological functions of glial release are poorly understood. Here we show that glutamate exocytosis from astrocytes of the rat hippocampal dentate molecular layer enhances synaptic strength at excitatory synapses between perforant path afferents and granule cells. The effect is mediated by ifenprodil-sensitive NMDA ionotropic glutamate receptors and involves an increase of transmitter release at the synapse. Correspondingly, we identify NMDA receptor 2B subunits on the extrasynaptic portion of excitatory nerve terminals. The receptor distribution is spatially related to glutamate-containing synaptic-like microvesicles in the apposed astrocytic processes. This glial regulatory pathway is endogenously activated by neuronal activity-dependent stimulation of purinergic P2Y1 receptors on the astrocytes. Thus, we provide the first combined functional and ultrastructural evidence for a physiological control of synaptic activity via exocytosis of glutamate from astrocytes.     

Analysis of CT features and quantitative texture analysis in patients with thymic tumors: correlation with grading and staging

Objectives

To evaluate potential relationship between qualitative CT features, quantitative texture analysis (QTA), histology, WHO staging, Masaoka classification and myasthenic syndrome in patients with thymic tumors.

Materials and methods

Sixteen patients affected by histologically proven thymic tumors were retrospectively included in the study population. Clinical information, with special regard to myasthenic syndrome and serological positivity of anti-AchR antibodies, were recorded. Qualitative CT evaluation included the following parameters: (a) location; (b) tumor edges; (c) necrosis; (d) pleural effusion; (e) metastases; (f) chest wall infiltration; (g) tumor margins. QTA included evaluation of “Mean” (M), “Standard Deviation” (SD), “Kurtosis” (K), “Skewness” (S), “Entropy” (E), “Shape from Texture” (TX_sigma) and “average of positive pixels” (MPP). Pearson–Rho test was used to evaluate the relationship of continuous non-dichotomic parameters, whereas Mann–Whitney test was used for dichotomic parameters.

Results

Histological evaluation demonstrated thymoma in 12 cases and thymic carcinoma in 4 cases. Tumor necrosis was significantly correlated with QTA Mean (p = 0.0253), MPP (p = 0.0417), S (p = 0.0488) and K (p = 0.0178). WHO staging was correlated with Mean (p = 0.0193), SD (p = 0.0191) and MPP (p = 0.0195). Masaoka classification was correlated with Mean (p = 0.0322), MPP (p = 0.0315), skewness (p = 0.0433) and Kurtosis (p = 0.0083). Myasthenic syndrome was significantly associated with Mean (p = 0.0211) and MPP (p = 0.0261), whereas tumor size was correlated with Mean (p = 0.0241), entropy (p = 0.0177), MPP (p = 0.0468), skewness (p = 0.009) and Kurtosis (p = 0.006).

Conclusion

Our study demonstrates significant relationship between radiomics parameters, histology, grading and clinical manifestations of thymic tumors.

     

Intraoperative limphonodal mapping in gastric, pulmonary and large bowel tumors. The sentinel limphonode technique

The concept of the sentinel lymphatic node was introduced by Cabanas in 1977, but it has proved to be successful for the treatment of the melanoma and breast cancer only since the 90s. Many studies have recently extended this technique to other neoplasias. This study deals with 36 patients who were to undergo surgery for 14 gastric adenocarcinomas, 11 of the colon and 11 pulmonary. Once the neoplastic mass was detected, 2 to 5 ml of a vital dye (Blu Patent) were injected in the serosa along the perimeter of the tumor by means of several 0.5 ml injections. A lymphatic node was diagnosed in 22 patients, respectively 10 gastric neoplasias, 6 pulmonary, 6 of the colon. In 14 cases the lymphatic node was found to be negative, in 8 cases positive. In the remaining 14 patients the lymphatic node was not detected. Although data do not always agree, the sentinel lymphatic node technique seems to have been successful for this kind of tumors. For this reason we have carried out this study and published our first data.     

Perineal excision of a large angiomyxoma in a young woman following magnetic resonance and angiographic imaging

BACKGROUND: Aggressive angiomyxomas are rare, arise from connective tissue of the perineum or the lower pelvis, and affect predominantly young women. CASE: We describe an unusual case of aggressive angiomyxoma in which the perineal approach was possible owing to MRI scanning and selective angiography indications. CONCLUSION: In cases of large aggressive angiomyxomas these diagnostic procedures should make it possible to decide which operative route might be best for the patient.     

Traesjugular intrahepatic portosystemic shunt in portai vein thrombosis: Role of the right gastric vein with anomalous insertion

Transjugular intrahepatic portosystemic shunt (TIPS) was performed in two patients with portal vein thrombosis. In both patients, hepatopetal flow had been maintained by an anomalous insertion of the right gastric vein (RGV) into the portal vein bifurcation and into the left portal branch respectively. In one patient, the main portal trunk could not be recanalized and the RGV was used as an accessory portal vein to place one stent for TIPS. In the other case, access through the partial portal-vein occlusion was gained and three stents were placed from the hepatic vein to the main portal vein distal to the thrombus. In portal vein thrombosis, the aberrant insertion of the RGV into the left or right portal branches may maintain patency of the intrahepatic portal system and, in case of unsuccessful recanalization of the porta, may represent the sole pathway for placing a TIPS