Reduced Retinal Function in the Absence of Nav1.6

Background: Mice with a function-blocking mutation in the Scn8a gene that encodes Nav1.6, a voltage-gated sodium channel (VGSC) isoform normally found in several types of retinal neurons, have previously been found to display a profoundly abnormal dark adapted flash electroretinogram. However the retinal function of these mice in light adapted conditions has not been studied. Methodology/Principal Findings: In the present report we reveal that during light adaptation these animals are shown to have electroretinograms with significant decreases in the amplitude of the a- and b-waves. The percent decrease in the a-and b-waves substantially exceeds the acute effect of VGSC block by tetrodotoxin in control littermates. Intravitreal injection of CoCl 2 or CNQX to isolate the a-wave contributions of the photoreceptors in littermates revealed that at high background luminance the cone-isolated component of the a-wave is of the same amplitude as the a-wave of mutants. Conclusions/Significance: Our results indicate that Scn8a mutant mice have reduced function in both rod and the cone retinal pathways. The extent of the reduction in the cone pathway, as quantified using the ERG b-wave, exceeds the reduction seen in control littermates after application of TTX, suggesting that a defect in cone photoreceptors contributes to the reduction. Unless the postreceptoral component of the a-wave is increased in Scn8a mutant mice, the reduction in the b-wave is larger than can be accounted for by reduced photoreceptor function alone. Our data suggests that th

Reliability and validity of needle biopsy evaluation of breast-abnormalities using the B-categorization – design and objectives of the Diagnosis Optimisation Study (DIOS)

<p>Abstract</p> <p>Background</p> <p>The planned nationwide implementation of mammography screening 2007 in Germany will increase the occurrence of mammographically detected breast abnormalities. These abnormalities are normally evaluated by minimal invasive core biopsy. To minimize false positive and false negative histological findings, quality assurance of the pathological evaluation of the biopsies is essential. Various guidelines for quality assurance in breast cancer diagnosis recommend applying the B-classification for histopathological categorization. However, to date there are only few studies that reported results about reliability and validity of B-classification. Therefore, objectives of our study are to determine the inter- and intraobserver variability (reliability study) and construct and predictive validity (validity study) of core biopsy evaluation of breast abnormalities. This paper describes the design and objectives of the DIOS Study.</p> <p>Methods/Design</p> <p>All consecutive asymptomatic and symptomatic women with breast imaging abnormalities who are referred to the University Hospital of Halle for core breast biopsy over a period of 24 months are eligible. According to the sample size calculation we need 800 women for the study. All patients in the study population underwent clinical and radiological examination. Core biopsy is performed by stereotactic-, ultrasound- or magnetic resonance (MR) guided automated gun method or vacuum assisted method. The histopathologic agreement (intra- and interobserver) of pathologists and the histopathologic validity will be evaluated. Two reference standards are implemented, a reference pathologist and in case of suspicious or malignant findings the histopathologic result of excision biopsy. Furthermore, a self administrated questionnaire which contains questions about potential risk factors of breast cancer, is sent to the participants approximately two weeks after core biopsy. This enables us to run a case-control-analysis (woman with breast cancer histological verified after excision are defined as cases, woman without malignant breast lesions are defined as controls) to investigate the predictive values of various risk factors on breast cancer risk.</p> <p>Conclusion</p> <p>The analysis of reliability and validity of the histopathological evaluation of core biopsy specimens of breast abnormalities is intended to provide important information needed for a high quality in breast cancer diagnostic and for planning of treatment strategies.</p

Influence of age on combined effects of cyclosporin and nifedipine on rat alveolar bone

Background: There is some evidence showing that cyclosporin A (CsA) and nifedipine (NIF) affect bone metabolism. The purpose of this work was to study the effects of CsA and NIF, given alone or concurrently, on alveolar bone of rats of different ages. Methods: Rats 15, 30, 60, and 90 days old were treated daily with 10 mg/kg body weight of CsA subcutaneously injected and/or 50 mg/kg body weight of NIF/day given orally for 60 days. Alveolar bone of the first lower molars was morphologically and stereologically evaluated in serial 5 mum bucco-lingual paraffin sections, stained with hematoxylin and eosin. Serum calcium and alkaline phosphatase levels were measured in all animals at the end of the experimental period. Results: Rats treated with CsA or NIF alone or CsA and NIF concurrently showed decreased alveolar bone density. CsA was more effective than NIF. A significant decrease in serum calcium was found only in animals treated with CsA or CsA/NIF. The results were similar regardless of age. Conclusions: These results indicate that the decrease in the alveolar bone volume in rats caused by CsA and NIF alone or concurrently is not age dependent. Furthermore, NIF (50 mg/kg) did not further increase the loss of alveolar bone volume induced by CsA (10 mg/kg).75226827

Role of protease-activated receptor-2 in inflammation, and its possible implications as a putative mediator of periodontitis

Proteinase-activated receptor-2 (PAR2) belongs to a novel subfamily of G-protein-coupled receptors with seven-transmembrane domains. This receptor is widely distributed throughout the body and seems to be importantly involved in inflammatory processes. PAR2 can be activated by serine proteases such as trypsin, mast cell tryptase, and bacterial proteases, such as gingipain produced by Porphyromonas gingivalis. This review describes the current stage of knowledge of the possible mechanisms that link PAR2 activation with periodontal disease, and proposes future therapeutic strategies to modulate the host response in the treatment of periodontitis