Management of hyperparathyroid-induced hypercalcaemic crisis with intracardiac thrombi.

A 29-year-old previously healthy patient presented with a hyperparathyroid-induced hypercalcaemic crisis refractory to conventional therapy. The patient developed ventricular fibrillation and subsequently required emergency parathyroidectomy and extracorporeal membrane oxygenation support. Extensive intracardiac and pulmonary trunk thrombi were identified soon after the commencement of extracorporeal membrane oxygenation, despite full anticoagulation. In this report we highlight the non-specific presentations of hypercalcaemia which may lead to delayed diagnosis, and discuss the incidence, risk factors and treatment of a hyperparathyroid-induced hypercalcaemic crisis. We emphasise the role of emergency parathyroidectomy as a salvage therapy in medically refractory We consider the likely factors leading to intracardiac thrombi formation in this case, including how hypercalcaemia may have been a contributing factor.

Once versus twice daily aspirin after coronary bypass surgery: a randomized trial.

Essentials Coronary artery bypass graft (CABG) failure is associated with myocardial infarction and death. We tested whether more frequent dosing improves aspirin (ASA) response following CABG surgery. Twice-daily compared with once-daily dosing reduces ASA hyporesponsiveness after CABG surgery. The efficacy of twice-daily ASA needs to be tested in a trial powered for clinical outcomes. SUMMARY: Background Acetyl-salicylic acid (ASA) hyporesponsiveness occurs transiently after coronary artery bypass graft (CABG) surgery and may compromise the effectiveness of ASA in reducing thrombotic graft failure. A reduced response to ASA 81 mg once-daily after CABG surgery is overcome by four times daily ASA dosing. Objectives To determine whether ASA 325 mg once-daily or 162 mg twice-daily overcomes a reduced response to ASA 81 mg once-daily after CABG surgery. Methods Adults undergoing CABG surgery were randomized to ASA 81 mg once-daily, 325 mg once-daily or 162 mg twice-daily. The primary outcome was median serum thromboxane B2 (TXB2 ) level on postoperative day 4. We pooled the results with those of our earlier study to obtain better estimates of the effect of ASA 325 mg once-daily or in divided doses over 24 h. Results We randomized 68 patients undergoing CABG surgery. On postoperative day 4, patients randomized to receive ASA 81 mg once-daily had a median day 4 TXB2 level of 4.2 ng mL-1 (Q1, Q3: 1.5, 7.5 ng mL-1 ), which was higher than in those randomized to ASA 162 mg twice-daily (1.1 ng mL-1 ; Q1, Q3: 0.7, 2.7 ng mL-1 ) and similar to those randomized to ASA 325 mg once-daily (1.9 ng mL-1 ; Q1, Q3: 0.9, 4.7 ng mL-1 ). Pooled data showed that the median TXB2 level on day 4 in groups receiving ASA 162 mg twice-daily or 81 mg four times daily was 1.1 ng mL-1 compared with 2.2 ng mL-1 in those receiving ASA 325 mg once-daily. Conclusions Multiple daily dosing of ASA is more effective than ASA 81 mg once-daily or 325 mg once-daily at suppressing serum TXB2 formation after CABG surgery. A twice-daily treatment regimen needs to be tested in a clinical outcome study.

Multiple daily doses of acetyl-salicylic acid (ASA) overcome reduced platelet response to once-daily ASA after coronary artery bypass graft surgery: a pilot randomized controlled trial.

BACKGROUND: The efficacy of ASA for prevention of graft failure following CABG surgery may be limited by incomplete platelet inhibition due to increased post-operative platelet turnover. OBJECTIVES: To determine whether acetyl-salicylic acid (ASA) 325 mg once-daily or 81 mg four-times daily overcomes the impaired response to ASA 81 mg once-daily in post-operative coronary artery bypass graft (CABG) patients. METHODS: We randomized 110 patients undergoing CABG surgery to either ASA 81 mg once-daily, 81 mg four times daily or 325 mg once-daily and compared their effects on serum thromboxane B2 (TXB2 ) suppression and arachidonate-induced platelet aggregation. RESULTS: One hundred patients were included in the final analysis. Platelet counts fell after surgery, reached a nadir on day 2, and then gradually increased. Although there was near complete suppression of TXB2 on the second or third post-operative day, TXB2 levels increased in parallel with the rise in platelet count on subsequent days. This increase was most marked in patients receiving ASA 81 mg once-daily and less evident in those receiving ASA four times daily. On post-operative day 4, (i) median TXB2 levels were lower with four times daily ASA than with either ASA 81 mg once-daily (1.1 ng/mL; Quartile(Q) Q1,Q3: 0.5, 2.4 and 13.3 ng/mL; Q1,Q3: 7.8, 30.8 ng/mL, respectively; P < 0.0001) or ASA 325 mg once-daily (3.4 ng/mL; Q1,Q3: 2.0, 8.2 ng/mL; P = 0.002), and (ii) ASA given four times daily was more effective than ASA 81 mg once-daily and 325 mg once-daily at suppressing platelet aggregation. CONCLUSIONS: Four times daily ASA is more effective than ASA 81 and 325 mg once-daily at suppressing serum TXB2 formation and platelet aggregation immediately following CABG surgery.

Real-world variability in dabigatran levels in patients with atrial fibrillation.

BACKGROUND: In clinical practice, physicians are given the choice of selecting one of two dabigatran doses based on patient characteristics, with the lower dose typically used in patients at a higher risk of bleeding. OBJECTIVES: The objectives of the study were to (i) estimate the inter- and intra-patient variability in dabigatran levels with 110 mg (DE110) and 150 mg (DE150) doses, (ii) examine the effect of physicians' dose selection on levels in DE110 and DE150 subgroups, and (iii) explore whether a single trough measurement identifies patients with extreme levels on subsequent visits. METHODS: In this prospective observational study of 100 patients with atrial fibrillation (AF), peak and trough levels of dabigatran were measured with the Hemoclot(®) assay at baseline and every 2 months thereafter (maximum four visits). RESULTS: Inter-patient variability in dabigatran levels (geometric coefficient of variation [gCV], 51-64%) was greater than intra-patient variability (gCV, 32-40%). Similar medians and distributions of levels were observed in DE110 and DE150 subgroups. Patients receiving DE110 were older, had lower renal function and weighed less than those receiving DE150. Up to 40% of patients whose trough levels were in the upper extremes, and up to 80% of patients whose trough levels were in the lower extremes at baseline, showed subsequent levels that fell in the middle quartiles. CONCLUSIONS: Our data support the practice of selecting the dabigatran dose based upon clinical characteristics because it results in similar levels of drug exposure in patients given DE110 or DE150. They do not support the concept that a single Hemoclot(®) measurement reliably identifies patients with consistently high or low values.

Die relief, seating methods and fit of full crowns.

This study investigated the influence of different frequencies of vibration supplied by an electropneumatic condenser on the seating rate and vertical discrepancy of full crowns with four different internal configurations: A) unrelieved; B) four layers of die spacer; C) eight layers of die spacer and D) unrelieved but vented occlusally. Crowns were luted with zinc phosphate cement under a static 5 Kg load alone and with three frequencies of vibration. The seating process was monitored electronically to determine seating rate and final fit. Venting and die relief enhanced seating under static load. Vibration increased the seating rate and reduced vertical discrepancy of groups B to D crowns compared to group A crowns. Medium frequency vibration with group C and D crowns gave the smallest vertical discrepancies. Vibration did not improve the final seating of group A crowns. This suggests that vibration is only effective when an escapeway of some kind is provided.

Molecular modelling of beta turns in a cyclic melanotropin.

Alpha-Melanocyte stimulating hormone (alpha-MSH) is a tridecapeptide which interacts with a family of G protein-coupled receptors, the melanocortin receptors, to cause its biological effects. We have modelled the low energy conformations of the alpha-MSH derivatives as part of a project to probe the receptor binding conformation of melanocortins, and also to design ligands for targeting cytotoxic drugs to MC1 receptors expressed by melanoma cells. Here we report a molecular dynamics study of beta turns in a cyclic lactam analogue [Nle4, Asp5, D-Phe7, Lys10]alpha-MSH. The data show that it is possible for a beta turn to exist in the ring portion of this molecule which contains the melanocortin conserved sequence - His-Phe-Arg-Trp-, even though the lowest energy conformers lack a beta turn.

Success rate in endodontic therapy--a retrospective study. Part II.

An evaluation of the success and failure in endodontic therapy performed by undergraduate students over a seven year period was made. The success rate was found to be 90.6%. Age and sex had no significant determination on the outcome of treatment. Further observations on other factors that might influence the prognosis of endodontic therapy were made and discussed in this paper.

Success rate in endodontic therapy--a retrospective study. Part I.

A survey was undertaken to review the success rate of endodontic treatment carried out by the undergraduates of the Dental Faculty, University of Singapore over a seven year period. A recall system resulted in a total of 385 cases which were successfully recalled and reviewed. The survey comprised of two parts:--A) history-taking from the endodontic record charts and B) clinical and radiographic evaluation of the cases. The cases in the survey had a minimum 2-year recall period. The success rate obtained was 90.6% which compared favourably with other studies. Root canals that were underfilled and root-fillings showing satisfactory apical compression were found to be more successful, the results being statistically significant (P less than 0.05). Endodontic therapy in non-vital teeth and a recall period of at least 2 years were also associated with a higher success rate. This paper discusses the overall success rate of endodontic therapy and the success and failure rate in relation to age and sex. The success rate in relation to other factors such as level of root-filling, apical compression and period of recall will be reported in a separate part of this paper.