Classification and cyclic fatigue evaluation of new kinematics for endodontic instruments

This study evaluated the effect of new motions of the motor TriAuto ZX2 on the cyclic fatigue of endodontic instruments. Vortex Blue 35.06 instruments were divided into four groups (n = 10) and tested for fatigue in a curved artificial canal (90° and 2 mm radius) using the following motions: continuous rotation (CR), Optimum Torque Reverse (OTR) set at 180° and the Optimum Glide Path (OGP), which was tested at 90° and 240°. The time to fracture (TTF) and the lengths of the fractured fragments were recorded. The mean TTF was significantly different among the groups (anova , P < 0.05): OGP 90° (213.39 ± 27.45), OTR 180° (121.24 ± 17.03), OGP 240° (45.24 ± 5.61) and CR (8.43 ± 1.27). Weibull analysis confirmed the shortest life expectancy for CR and the longest survival for OGP at 90°. The resistance to fatigue was affected by motions and pre‐set angles. The proprietary movements that are currently available for endodontic instruments were classified according to their kinematics.     

Update in orthopaedic oncology.

Orthopaedic oncology is a growing field with unanswered questions. Improvements in imaging have led to increases in limb salvage surgery. Chemotherapy is indicated in most bone sarcomas but varied agents are used. Newer surgical procedures such as an internal hemipelvectomy and resection using an expandable prothesis are currently being evaluated. Further research in all areas is indicated.     

Complications associated with limb salvage for extremity sarcomas and their management

A retrospective clinical review of 100 consecutive patients with extremity sarcomas managed by limb salvage operations was performed to evaluate local tumor control and morbidity. The mean follow-up period was 45.1 months. Overall survival was 86%. There were local recurrences in 3% of patients, and 26 complications in 22 patients. Wound necrosis was the most frequent complication. Failure of allogeneic bone graft operations occurred in 25 patients. Most of the complications were salvageable without loss of limb. Limb salvage is an acceptable surgical treatment of extremity sarcomas based on adequate local control and minimal morbidity.     

Focal reduction of villous blood flow in early indomethacin enteropathy: a dynamic vascular study in the rat

Background—Oral indomethacin causes villousshortening, microvascular damage, and distortion, which might inducemucosal ischaemia and necrosis.
Aims—In order to determine the early events inindomethacin induced jejunal injury we examined the temporal relationsbetween morphological damage and changes in villous blood flowfollowing indomethacin.
Methods—In anaesthetised rats, mid jejunal villiwere exteriorised in a chamber and observed by fluorescence microscopy.Blood flow in surface capillaries was calculated from velocities and diameters. Indomethacin was applied by both luminal and intravenous routes for 90 minutes, after which the animal was perfusion fixed andthe villi were processed for histological examination. Control animalsreceived intravenous or luminal bicarbonate (1.25%).
Results—Blood flow slowed in individual villi at20 minutes, and progressed to complete stasis (in another group) by 45 minutes. Histological examination at 20 minutes revealed microvascular distortion, but no villous shortening: crypt depth:villous height ratios were 0.356 (0.02) in test and 0.386 (0.01) in surrounding villi(p>0.5). At stasis, the villi under study showed epithelial clumpingand were shortened: crypt depth:villous height ratios were 0.92 (0.2)in test and 0.42 (0.06) in surrounding villi (p<0.02). Vehicle alonehad no effect on either blood flow or histology.
Conclusions—Focal slowing of villous blood flowand microvascular distortion precede villus shortening and epithelialdisruption, and indicate that damage to surface microvasculature is anearly event in indomethacin induced mucosal injury in this model.

Keywords:indomethacin; jejunum; villi; microcirculation; endothelium; microthrombi

     

Acute effects of the selective cholinergic channel activator (nicotinic agonist) ABT-418 in Alzheimer’s disease

To explore further the potential for cognitive enhancement utilizing nicotinic stimulation in Alzheimer’s disease (AD), six otherwise healthy subjects with moderate AD received placebo and three doses (6, 12, and 23 mg) of the novel selective cholinergic channel activator (ChCA) (nicotinic agonist) ABT-418 over 6 h in a double-blind, within-subjects, repeated-measures design. Subjects showed significant improvements in total recall and a decline in recall failure on a verbal learning task. Qualitatively similar improvements were seen in non-verbal learning tasks such as spatial learning and memory, and repeated acquisition. No significant behavioral, vital sign, or physical side effects were seen. These results confirm that stimulating central nicotinic receptors has acute cognitive benefit in AD patients. These findings suggest that selective ChCAs have a potential therapeutic role in dementing disorders, and that further studies with this or similar agents in AD and/or Parkinson’s disease are warranted. Received: 27 February 1998/Final version: 9 September 1998     

Bile-salt metabolism in the primate fetus.

Fetal bile salt metabolism was assessed by the intravenous infusion of e114C]cholate into 6 monkey fetuses. The placental transfer, fetal plasma clearance, and fetal hepatic excretion of the administered radiolabeled bile salt were measured. Placental transfer averaged 30% of the injected dose, while biliary excretion averaged 36%. Of the amount excreted by the fetal liver, 78% was in the form of [14C]taurocholate. The findings suggest that bile salt metabolic and excretory mechanisms are undergoing developmental maturation at birth.     

Accuracy of electronic apical functions of a new integrated motor compared to the visual control of the working length—an ex vivo study

Clinical Oral Investigations - To evaluate ex vivo the efficacy of the integrated motor Tri Auto ZX2 in controlling the apical extent of preparation compared to conventional visual control (CVC) of...