Impairment of synaptic plasticity by the stress mediator CRH involves selective destruction of thin dendritic spines via RhoA signaling.

Stress is ubiquitous in modern life and exerts profound effects on cognitive and emotional functions. Thus, whereas acute stress enhances memory, longer episodes exert negative effects through as yet unresolved mechanisms. We report a novel, hippocampus-intrinsic mechanism for the selective memory defects that are provoked by stress. CRH (corticotropin-releasing hormone), a peptide released from hippocampal neurons during stress, depressed synaptic transmission, blocked activity-induced polymerization of spine actin and impaired synaptic plasticity in adult hippocampal slices. Live, multiphoton imaging demonstrated a selective vulnerability of thin dendritic spines to this stress hormone, resulting in depletion of small, potentiation-ready excitatory synapses. The underlying molecular mechanisms required activation and signaling of the actin-regulating small GTPase, RhoA. These results implicate the selective loss of dendritic spine sub-populations as a novel structural and functional foundation for the clinically important effects of stress on cognitive and emotional processes.

Trends of hepatitis A hospitalizations and costs associated with the hospitalization in Spain (2000-2005).

The objective of this study was to analyse data related to hospitalization, comorbidities, average stays and costs associated with the hospitalization cases of hepatitis A in Spain, during the period between 2000 and 2005. A retrospective, descriptive study of the epidemiological characteristics of hepatitis A patients admitted to Spanish hospitals was performed using, as an information source, the Minimum Basic Data Set. National hospitalization rates were calculated for hepatitis A. Comorbidities, mortality, average and median stays, and mean medical costs related to hospitalization were analysed. Costs were calculated using Diagnosis-Related Groups for the disease. The total number of hospitalized patients with hepatitis A diagnosis was 2351 subjects (rate 1.87/100,000 inhabitants). The highest rate corresponds to the group aged between 20 and 39 years (3.07/100,000 inhabitants). Some 60.1% of hospitalized hepatitis A cases were diagnosed in men. Twenty-two deaths (0.9%) out of the total of hospitalized subjects were reported. The average hospital stay caused by hepatitis A was 6.8 days. The trends in the rate of hospitalized hepatitis A cases in Spain, from the year 2000 to 2005, were not statistically significant. Differences were found neither in the hospitalization percentage, nor in the average length of stay. An increase of cost from 836,278 euro in the year 2000 to 1,272,608 euro in the year 2005 was observed. The rate of hospitalized hepatitis A subjects in Spain has not changed over the period 2000-2005. The total cost derived from these hospitalizations has increased by 52%.

[Density-mask spiral computed tomography in patients who are candidates for a lung-volume-reduction intervention: a preliminary study]. / La Tomografia Computerizzata spirale con maschera della densità nei pazienti candidati a intervento di riduzione del volume polmonare: studio preliminare.

PURPOSE: To investigate the usefulness of helical CT with multiplanar reconstructions and density mask in emphysematous patients candidate for lung volume reduction surgery (LVRS), in order to assess the feasibility of surgery and for surgical planning. MATERIAL AND METHODS: Twenty emphysematous patients (5 women and 15 men; age range: 55-67 years, mean: 61) candidate for LVRS were submitted to isotope perfusion scanning, chest radiography during maximal inspiration and expiration and Helical CT with the low volume contrast technique, multiplanar reconstructions and density mask. RESULTS: Only 8 of the 20 patients examined were submitted to LVRS. They had irregular distribution of emphysema at isotope perfusion scanning and density mask CT. Surgery consisted in an atypical resection of the upper lobe portions which appeared most damage with both techniques. Six of the remaining 12 nonsurgical patients were excluded because of homogeneous distribution of emphysema at both CT and perfusion scanning, which was incompatible with surgery. Lung transplant was considered for 4 of these patients, but only 2 of them actually received it. Three patients were excluded from LVRS because of excessive diaphragm excursion during expiration at chest radiography and of multiple confluent areas of emphysema in both lung at CT and perfusion scanning. One patient with a large area of emphysema in the right upper lobe at CT and perfusion scanning was excluded due to associated severe interstitial disease. Another patient with emphysema mainly involving the lower lobes, as clearly depicted with both techniques, was excluded because the emphysema was secondary to alpha 1-antitrypsin deficiency, a condition known to have a less favorable surgical outcome. Finally, one patient was excluded due to a previous upper transverse laryngectomy, although CT and perfusion scanning patterns were compatible with surgery. CONCLUSIONS: In our opinion, density mask helical CT yields more accurate and clearer images than perfusion scanning, and allows the patients candidate for surgery to undergo a single examination to evaluate the extent and distribution of emphysema and to detect other possible pathological conditions. Though ours was a small series, the results suggest that perfusion scanning be integrated with density mask helical CT, the latter a very important technique for surgical planning.