The brain as a target for adrenocortical steroids: cognitive implications.

It is well established that a reciprocal control exists between the brain and glucocorticoid hormones. The brain regulates adrenocortical function via hypothalamic corticotrophin releasing hormone-41 (CRH-41), glucocorticoids act at specific receptors in the hippocampus, thus promoting negative feedback mechanisms. Because the hippocampus is a major site for memory processes, a role for excessive/long-lasting plasma glucocorticoid levels has been suggested in conditions of mental impairment. Major depression, Cushing's disease, and dementia of the Alzheimer type are disorders which share hyperactivity of the hypothalamo-pituitary-adrenal axis, as well as symptoms of cognitive decline. Although the mechanisms leading to hypercortisolemia appear to be different in each case, the neuropsychological features of these three disorders accord with the hypothesis of glucocorticoid-associated brain damage. It therefore is important to find pharmacological strategies that will avert or reduce these potential consequences on brain function.     

Recurrent caecal volvulus in mesenterium commune. A case report

We report a case of recurrent abdominal pain due to intermittent caecal volvulus arising in a patient with mesenterium commune. Colonic enema, abdominal CT scan and virtual colonography with three-dimensional colonic reconstruction were useful for detecting this rare abnormal intestinal fixation. Although right hemicolectomy was indicated, we performed a wide colonic resection from the terminal ileum to the distal sigmoid because the patient's short mesentery made it impossible to perform an ileum-transverse anastomosis. At six months follow-up, the patient was in good health and free of abdominal symptoms.     

To fix or not to fix? The role of fibular fixation in distal shaft fractures of the leg

Background

The role of stabilisation of the fibula in distal two-bone fractures of the leg is controversial. Some studies indicate the need for fibular stabilisation in 43 AO fractures, but few studies consider the role of the fibula in 42 AO fractures. The aim of the current paper is to explain the role of stabilisation of the fibula in 42 AO fractures, correlating the rates of healing and non-union between patients with and without fibula fixation.

Materials and methods

A total of 60 patients with 42 AO (distal) shaft fracture of the tibia with associated fracture of the fibula were selected. Patients were divided into two groups according to whether or not the fibula was fixed: Group I (n = 26) comprised patients who had their fibula fixed while Group II (n = 34) comprised patients who did not. The fibular fracture was classified according to the AO and related to the level of the tibial fracture. Other parameters examined were the union rate of the two groups correlated to the fracture pattern and position of the fibular fracture; the demographic data, such as age and gender; the presence of an open fracture, and the type of tibial fixation device used (nail or plate).

Results

None of the parameters considered (open injury, AO classification, device used and level of the fibular fracture relative to the tibial) were shown to have an influence on the development of a non-union.

Conclusion

This study showed a higher non-union rate when the fracture of the tibia and fibula were at the same level, the tibia was fixed with a bridging plate and the fibula left untouched. For this reason, we recommend fibular fixation in all 42 distal fractures when both fractures lie on the same plane and the tibial fracture is relatively stabilised.     

Optical coherence tomography versus stereoscopic fundus photography or biomicroscopy for diagnosing diabetic macular edema: a systematic review

PURPOSE: To review systematically the sensitivity and specificity of optical coherence tomography (OCT) for diagnosing macular edema attributable to diabetic retinopathy compared with well-established gold standard tests such as fundus stereophotography or contact and noncontact fundus biomicroscopy. METHODS: Medline and Embase were searched electronically and six major ophthalmic journals from 1998 to 2006 were hand searched. Two reviewers independently assessed trial searches, studied quality with the QUADAS (Quality Assessment of Diagnostic Accuracy Studies) checklist, and extracted data. The target disease was clinically significant macular edema (CSME) according to Early Treatment of Diabetic Retinopathy Study (ETDRS) criteria. A bivariate model was used to obtain summary estimates of sensitivity and specificity and fit a summary receiver operating characteristic (ROC) curve. RESULTS: Fifteen studies were considered eligible. These studies were of good quality for most items of the QUADAS checklist, but most studies did not report masking of examiners and did not describe how withdrawals and undetermined results were treated. Seven studies included healthy control subjects, which could have artificially enhanced OCT diagnostic performance. All but one study included both eyes of the patients without taking into account the within-subject correlation in statistical analyses. Sensitivity and specificity data could be extracted from only 6 of 15 studies, because appropriate cross tabulations of index and reference tests were not reported by the others. In five of these studies, central retinal thickness cutoffs between 230 and 300 microm were adopted to define abnormal OCT results and considered the central type of CSME only, whereas in one study a complex algorithm accounting for extrafoveal CSME was used. The design of one study was case-control and was excluded from the meta-analysis. The expected operating point on the summary ROC, a pooled estimate of all studies, corresponded to a sensitivity of 0.79 (95% CI: 0.71-0.86), a specificity of 0.88 (95% CI: 0.80-0.93), a positive likelihood ratio of 6.5 (95% CI: 4.0-10.7), and a negative likelihood ratio of 0.24 (95% CI: 0.17-0.32). These values suggest a good overall performance of OCT for diagnosing CSME. CONCLUSIONS: OCT performs well compared with fundus stereophotography or biomicroscopy to diagnose diabetic macular edema. The quality of reporting of such studies should be improved, and authors should present cross tabulations of index and reference test results. Data adjusted for within-subject correlation should also be provided, although this issue represents a challenge for systematic reviewers.     

Degree of Mineralization at the Attachment of Lateral Pterygoid

The degree of mineralization of bone (DMB) in the human mandibular condyle is heterogeneous, and differences in DMB have been related to variations in bone turnover caused by local strains. The lateral pterygoid muscle inserts at the anterior surface of the condyle. The aim of this study is to analyze the DMB at the attachment of this muscle as compared with a control region. It was hypothesized that, DMB at the attachment sites of lateral pterygoid muscles was lower than at the control regions, because of the larger number of loadings and subsequently higher remodeling rates. Also, as the human lateral pterygoid muscle is heterogeneous in its internal architecture, variations in DMB within the attachment sites were expected. 10 human mandibular condyles were scanned in a micro CT system. Within each condyle, two regions, that is, the pterygoid fovea and a posterior (control) region where no muscle was inserted, were selected to analyze regional differences in DMB. The attachment site was further divided into eight subregions to analyze subregional differences. At the pterygoid fovea the DMB of cortical bone was significantly lower than at the control region (p = 0.003) and increased in medio‐lateral direction. The results of this study could suggest an influence of the lateral pterygoid muscle on bone turnover at this site. Anat Rec 293:1387–1392, 2010. © 2010 Wiley‐Liss, Inc.     

Down-regulation of nitric oxide synthase-2 and cyclooxygenase-2 pathways by p53 in squamous cell carcinoma

The goal of this study was to analyze the correlation between inducible nitric oxide synthase (iNOS) and COX-2 activities and p53 gene status in head and neck squamous cell carcinomas (HNSCCs) in vivo and in vitro. In a series of 43 HNSCCs we observed an up-regulation of both iNOS and COX-2 pathways in tumor tissues and both activities were correlated each other (rs = 0.612 and P = 0.0002). We also found that p53-mutated HNSCCs (25 cases, 58.1%) showed higher levels of iNOS activity and cGMP in comparison with wild-type p53 tumors (18 cases, 41.9%) (P = 0.0005 and P = 0.01), as well as higher iNOS immunohistochemical expression (P = 0.03). Analogously, higher PgE2 levels were documented in p53-mutated HNSCCs when compared with wild-type p53 tumors (P = 0.015) and COX-2 protein expression was higher in p53-mutated HNSCCs (P = 0.007). A431 cancer cells expressing a p53 temperature-sensitive mutant showed an approximately 1.9- and 2.6-fold decrease in spontaneous NO(2-)/NO(3-) and PgE2 synthesis at permissive temperature, respectively, when compared with the same cells at nonpermissive temperature (P 相似文献   

Timing and significance of exercise-induced left ventricular outflow tract pressure gradients in hypertrophic cardiomyopathy

The relation of exercise-induced left ventricular (LV) outflow tract obstruction to functional capacity in hypertrophic cardiomyopathy (HC) is incompletely defined. Thus, we assessed the patterns of onset of physiologically provoked LV outflow gradients and exercise performance in 74 consecutive patients with HC (age 45 ± 16 years; 74% men) without LV outflow obstruction at rest. The subaortic gradients were measured serially using echocardiography in these 74 patients during maximum, symptom-limited, upright bicycle exercise testing. The time course of the provoked gradients and the relation to exercise performance were assessed. Of the 74 patients, 30 (41%) developed a dynamic LV outflow gradient of ≥30 mm Hg (mean 78 ± 37 mm Hg) during upright exercise testing that correlated highly with the gradients measured with the patients supine during the immediate recovery period (R2 = 0.97). The 16 patients in whom outflow obstruction developed rapidly at low exercise levels (≤5 METs) had a significantly reduced exercise capacity (6.1 ± 1.3 vs 8.0 ± 1.6 METs; p <0.01) compared to the other 14 patients in whom obstruction appeared later at greater exercise levels of >5 METs. The timing of the gradient onset was not predictable from the baseline clinical and echocardiographic features, peak exercise LV outflow tract gradient, or symptoms. In conclusion, in patients with HC without outflow obstruction at rest, the earlier onset of LV outflow tract gradients during physiologic exercise was associated with impaired exercise performance. These findings have provided insights into the determinants of functional impairment in HC and support the potential value of exercise echocardiography in the clinical assessment of patients with HC.