Influence of the punch diameter and curvature on the yield pressure of MCC-compacts during Heckel analysis.

The volume reduction behaviour of powders has been quantified by means of the 'in-die' yield pressure (YP) using Heckel analysis. However, because different YPs are reported for the same material, the experimental conditions influencing this material-constant were investigated. Silicified microcrystalline cellulose was compressed into flat-faced and convex tablets using a compaction simulator instrumented with load and displacement transducers. During compression, upper and lower punch force and displacement data were recorded and corrected for punch deformation. A symmetrical triangle wave compression profile was used and the instantaneous punch velocity was kept constant (5mm/s). Individual tablet height and weight were used for Heckel analysis. The influence of the 'effective compression pressure' (P(EFF)) (ranging from 10 to 350 MPa), punch diameter (PD) (4, 9.5 and 12 mm) and filling depth (FD) (4.5, 7.5 and 10.5mm) on YP was statistically evaluated using Response Surface Modelling software. A quadratic surface response equation, describing the relationship between P(EFF), PD, FD and YP, was proposed for concave (Adj R(2): 0.8424; S.D.: 14.60 MPa) and flat-faced (Adj R(2): 0.8409; S.D.: 4.49 MPa) punches. YP and tensile strength were mainly determined by P(EFF), irrespective of punch curvature. FD and PD had only a minor influence on the YP, although more pronounced for the concave punches. The method used resulted in reproducible P(EFF) and tensile strength values and the flat-faced tablets showed less weight variation. Flat-faced punches are preferred over punches with a concave surface when investigating the volume reduction behaviour of a powder by means of Heckel analysis and the experimental parameters should be reported.     

Dantrolene protects hippocampal cells from damage induced by TsTX, an alpha-scorpion toxin from Tityus serrulatus.

We examined the effects of dantrolene, an inhibitor of intracellular calcium release, on alterations associated with the intrahippocampal injection of the TsTX scorpion toxin. Male Wistar rats (230-250 g) were injected with Ringer solution (1 microl; n = 6); TsTX toxin (1 microg/microl; n = 8); and dantrolene (10.0 mg/kg) plus TsTX toxin (1 microg/microl; n = 6). After injection, electroencephalographic (EEG) recordings and observation of animals behaviour were performed continuously for 4 h. One week later, animals were submitted to histopathological analysis. TsTX caused electrographic seizure expressed by moderate or intense discharges and neuronal loss in hippocampal areas in all injected animals (n = 8). Dantrolene reduced the effect of TsTX. Thus, 67% of rats (four out of six) treated with toxin and dantrolene had electrographic convulsions, but only for 30 min after injection and none of them presented neuronal damage. Dantrolene or Ringer had no effects on the EEG.     

Intrusion of overerupted molars with temporary anchorage devices before prosthetic reconstruction: A case report

Extraction of teeth without adequate prosthetic rehabilitation frequently can lead to overeruption of opposing teeth, which may cause occlusal disturbances and complicate dental restoration. Equilibration with consequent need of endodontic treatment, surgical intrusion or extraction are often indicated as a remedy in such cases. The article proposes a method of orthodontic intrusion with the use of temporary anchorage devices as a predictable and less invasive option. Important clinical aspects of molar intrusion with respect to surrounding anatomical structures are also discussed.     

Die Methode von Schützenberger-Siegfried zur Bestimmung des beweglichen Blutsauerstoffes

Ohne Zusammenfassung     

Repair of thoracic aortic aneurysm due to noninfectious aortitis

Abstract Background and aim: Isolated thoracic aortitis (ITA) is a newly‐defined pathological entity with a still‐unknown etiopathology and with some potential relationship to IgG4‐related systemic disease. We investigated patients on whom the ascending aorta was operated to identify the clinical and histopathological features of ITA and its relationship to IgG4‐related systemic disease. Methods: Two hundred fifty‐one patients underwent replacement of the ascending aorta. Retrospective review of all histological reports was done to identify noninfectious aortitis. Immunohistochemical analysis of resected specimens was performed in all cases. Results: We found 11 (4.4%) patients with noninfectious aortitis aged 52 to 79 years; nine of the patients were female. All patients underwent ascending aorta replacement. The 30‐day mortality was 0. During the follow‐up period (median 12 months) four patients died (two of them because of progression of aortic disease). None of the seven living patients developed any IgG4‐related diseases, and all had normal serum levels of IgG and IgG4. Conclusions: Surgical treatment of ITA has acceptable short‐ and mid‐term results. Because follow‐up serum levels of IgG and IgG4 were normal in survivors, postoperative corticosteroid therapy may not be indicated in patients in the absence of active vasculitis.