Activity-dependent PSD formation and stabilization of newly formed spines in hippocampal slice cultures

Development and remodeling of synaptic networks occurs through a continuous turnover of dendritic spines. However, the mechanisms that regulate the formation and stabilization of newly formed spines remain poorly understood. Here, we applied repetitive confocal imaging to hippocampal slice cultures to address these issues. We find that, although the turnover rate of protrusions progressively decreased during development, the process of stabilization of new spines remained comparable both in terms of time course and low level of efficacy. Irrespective of the developmental stage, most new protrusions were quickly eliminated, in particular filopodia, which only occasionally lead to the formation of stable dendritic spines. We also found that the stabilization of new protrusions was determined within a critical period of 24 h and that this coincided with an enlargement of the spine head and the expression of tagged PSD-95. Blockade of postsynaptic AMPA and NMDA receptors significantly reduced the capacity of new spines to express tagged PSD-95 and decreased their probability to be stabilized. These results suggest a model in which synaptic development is associated with an extensive, nonspecific growth of protrusions followed by stabilization of a few of them through a mechanism that involves activity-driven formation of a postsynaptic density.     

Comparison among total knee arthroplasties with a mobile bearing: menisci versus rotating platform versus AP glide platform

A retrospective study was conducted on 60 patients (53 females, seven males with a mean age of 68 years and 5 months) who underwent a total knee replacement using a mobile bearing. The diagnosis was primary osteoarthritis in 57 cases and rheumatoid arthritis in three cases. None of the patients underwent a bilateral procedure, thus 60 implants (33 all cementless, three all cemented, 24 with only the tibial component cemented) were considered. Three different groups were identified:

• Group 1: first 20 total knee arthroplasties with menisci.
• Group 2: first 20 total knee arthroplasties with rotating platform.
• Group 3: first 20 total knee arthroplasties with AP glide platform.

Clinical and radiological results at the final follow up, although different in time among the three groups, have shown no revision due to mechanical or septic reasons, and no signs of impending failure.     

Liver Surgery for Colorectal Metastases: Results after 10 Years of Follow-Up. Long-Term Survivors,Late Recurrences,and Prognostic Role of Morbidity

Background  Liver surgery is the gold-standard treatment of colorectal liver metastases. Five-year survival rates may be inadequate to evaluate surgical outcomes because some patients are alive with recurrence and late recurrences are possible. The aim of this study was to analyze 10-year survival outcome in terms of late recurrence rate and prognostic factors of survival. Methods  One hundred twenty-five patients underwent liver resection for colorectal liver metastases between 1985 and 1996. Four patients who experienced postoperative mortality were excluded. The analysis was performed on 121 patients. Results  Five- and 10-year survival rates were 23.1% and 15.7%, respectively. Nineteen patients were alive 10 years after liver resection and 17 were disease-free (5 after re-resection). Five- and 10-year disease-free survival rates were 17.4% and 14.8%, respectively. In patients with recurrence, re-resection significantly improved survival (P < 0.001); 98% of recurrences occurred within the first 5 years, but 15% of patients disease-free at 5 years developed later recurrence. Multivariate analysis evidenced five independent negative prognostic factors of survival: male sex (P = 0.029), synchronous metastases (P = 0.011), >3 metastases (P < 0.001), metastatic infiltration of nearby structures (P < 0.001), and postoperative morbidity (P < 0.001). In 17 patients without negative prognostic factors the 10-year survival rate was 35.3%. Conclusion  Liver resection for colorectal liver metastases may be curative in more than one-third of patients without negative prognostic factors. Postoperative morbidity significantly worsens long-term outcomes. The risk of recurrence after liver resection is high even after 5 years of follow-up, but re-resection can improve the outcome.     

Enterogenous cysts of the cerebellopontine angle: short review illustrated by two new patients

Summary Intracranial enterogenous cysts are an uncommon entity rarely found in the midline within the posterior cranial fossa. The occurrence of an enterogenous cyst in the cerebellopontine angle is exceptional. We present two new cases of cerebellopontine angle (CPA) enterogenous cysts and review the literature to clarify the diagnosis and the management of these lesions. Eighteen cases of CPA intradural enterogenous cysts have been reported to date, including the two cases presented in this article. All of them were symptomatic and underwent surgical treatment. After surgery, the symptomatic recurrence occurred in 31% of the patients, most of which had partial excision. Considering our patients and the published cases in the literature we suggest that the aim of surgery should be total removal of cyst and its content whenever possible. When partial resection of the cyst is performed, we recommend long-term clinical and neuroradiological follow-up. Correspondence: Paolo Perrini, MD, Neurosurgical Department, Hope Hospital, Salford, Manchester, UK.     

Bile leak after hepatectomy: predictive factors of spontaneous healing

BACKGROUND: Bile leakage after hepatectomy usually has spontaneous healing, but some patients require interventional procedures. To identify early predictive factors of conservative management failure. METHODS: This study focused on patients with bile leak after hepatectomy without extrahepatic biliary resection from 1996 through 2006. RESULTS: Bile leakage occurred in 34 of 593 patients (5.7%). Conservative management was successful in 26 patients (76.5%). At univariate analysis overall associated resections, vascular associated resections, and drainage output on days 1, 3, and 10 from leak onset were significant negative predictors of spontaneous healing. At multivariate analysis drainage output greater than 100 mL on day 10 was the only independent prognostic factor of conservative management failure (relative risk, 55.985; P = .008) with 80% sensitivity, 93.3% specificity, and 90% accuracy. CONCLUSIONS: Wait-and-see treatment is successful in most cases. Patients with drainage output greater than 100 mL 10 days after bile leakage diagnosis should be scheduled for interventional treatments.     

Continuous positive airway pressure for treatment of respiratory complications after abdominal surgery: a systematic review and meta-analysis

OBJECTIVE: We evaluated the potential benefit of continuous positive airway pressure (CPAP) to prevent postoperative pulmonary complications (PPCs), atelectasis, pneumonia, and intubation in patients undergoing major abdominal surgery. SUMMARY BACKGROUND DATA: PPCs are common during the postoperative period and may be associated with a high morbidity rate. Efficacy of CPAP to prevent PPCs occurrence is controversial. METHODS: Medical literature databases were searched for randomized controlled trials examining the use of CPAP versus standard therapy in patients undergoing abdominal surgery. The meta-analysis estimated the pooled risk ratio and the number needed to treat to benefit (NNTB) for PPCs, atelectasis, and pneumonia. RESULTS: The meta-analysis was carried out over 9 randomized controlled trials. Overall, CPAP significantly reduced the risk of (1) PPCs (risk ratio, 0.66; 95% confidence interval [CI], 0.52-0.85) with a corresponding NNTB of 14.2 (95% CI, 9.9-32.4); (2) atelectasis (risk ratio, 0.75; 95% CI, 0.58-0.97; NNTB, 7.3; 95% CI, 4.4-64.5); (3) pneumonia (risk ratio, 0.33; 95% CI, 0.14-0.75; NNTB, 18.3; 95% CI, 14.4-48.8). In all cases the variation in risk ratio attributable to heterogeneity was negligible, although there was some evidence of publication bias. CONCLUSIONS: This systematic review suggests that CPAP decreases the risk of PPCs, atelectasis, and pneumonia and supports its clinical use in patients undergoing abdominal surgery.