Syntheses and Structures of Ruthenium Complexes Containing a Ru-H-Tl Three-Center-Two-Electron Bond.

Treatment of CpRuH(PP) (PP=dppm, dppe) with TlPF6 produced [CpRu(H)(Tl)(PP)]PF6 . X-ray diffraction and computational studies suggest that the complexes contain a Ru-H-Tl 3c-2e bond and can be viewed as the first σ-complexes of period 6 main-group hydrides [CpRu{η2 -(H-Tl)}(PP)]PF6 or [Tl{η2 -H-RuCp(PP)}]PF6 . The complexes can be stored as a solid at room temperature for days without appreciable decomposition, but are unstable in solution and evolved to the trimetallic complexes [{CpRu(PP)}2 (µ-Tl)]PF6 .

Management of the low-flow head and neck vascular malformations in children: the sclerotherapy protocol.

AIM: Image-guided sclerotherapy is becoming the preferred treatment for low-flow vascular malformations in head and neck region. The authors review the management protocol for this condition and evaluate its clinical outcomes. METHODS: Children with low-flow vascular malformations in head and neck region undergoing sclerotherapy from 2010 to 2013 were reviewed. All patients were assessed by pediatric surgeons and interventional radiologists in the multidisciplinary vascular anomalies clinic. Ultrasonography and intravenous contrast enhanced magnetic resonance imaging were performed preoperatively. Under general anesthesia with endotracheal intubation, sclerotherapy were performed with ultrasonographic and fluoroscopic guidance. Sodium tetradecryl sulfate (STS) foam or ethanolamine was used for venous malformation and doxycycline for lymphatic malformations as primary sclerosants, whereas 98% ethanol was reserved as an adjuvant sclerosant in selected cases of repeated procedures. Perioperative dexamethasone 0.2 mg/kg thrice daily was administered to decrease postsclerotherapy swelling and single dose intravenous mannitol 0.5 g/kg was given to minimize thromboembolic complications. Postoperatively, patients were admitted to intensive care unit for mechanical ventilation under deep sedation for airway protection. RESULTS: Overall 13 children (8 male and 5 female) with a mean age of 25 months (range, 2 mo-11 y) underwent a total of 25 sessions of image-guided staged sclerotherapy. There were five venous and eight lymphatic malformations. Location wise there were eight cervical, one lingual, one parotid, one lip, one facial, and one palatal lesions. Six patients had obstructive airway symptoms. Five patients required staged sclerotherapies from two to six sessions. There were no airway and thromboembolic complications. One patient had bleeding while another had recurrent swelling following sclerotherapy for lymphatic malformations and they were treated by aspiration. Significant size reductions of more than 50% volume were achieved in all patients. All patients with obstructive symptoms showed improvement. CONCLUSION: Sclerotherapy is a safe and effective treatment for head and neck vascular malformations in children. Routine perioperative protocol is essential to reduce airway and thromboembolic complications. Size reduction and functional improvement occurred in all patients undergoing sclerotherapy.

RuH2(CO)(PPh3)3 catalyzed selective formation of 1,4-disubstituted triazoles from cycloaddition of alkynes and organic azides.

The ruthenium hydride complex RuH(2)(CO)(PPh(3))(3) was found to be an effective catalyst for the cycloaddition reactions of terminal alkynes and azides. In the presence of RuH(2)(CO)(PPh(3))(3), various azides reacted with a range of terminal alkynes to produce 1,4-disubstituted 1,2,3-triazoles with 100% selectivity and moderate to excellent yields.

Children suspected of having pulmonary embolism: multidetector CT pulmonary angiography--thromboembolic risk factors and implications for appropriate use.

PURPOSE: To evaluate thromboembolic risk factors for pulmonary embolism (PE) detected by using computed tomographic (CT) pulmonary angiography in children and to determine whether such information could be used for more appropriate use of CT pulmonary angiography in this patient population. MATERIALS AND METHODS: The institutional review board approved this HIPAA-compliant retrospective study and waived the need for patient informed consent. Two hundred twenty-seven consecutive CT pulmonary angiography studies in 227 pediatric patients who underwent CT pulmonary angiography for clinically suspected PE at a single large pediatric referral hospital between July 2004 and March 2011 were evaluated. Age, sex, referral setting, and D-dimer result, as well as seven possible risk factors, were compared between patients with and those without PE. Multiple logistic regression modeling was used to identify the independent risk factors of PE. Receiver operating characteristic curve analysis was applied to determine the optimal cutoff number of risk factors for predicting a positive CT pulmonary angiography result for PE in children. RESULTS: Thirty-six (16%) of 227 CT pulmonary angiography studies were positive for PE. Five risk factors, including immobilization (P < .001), hypercoagulable state (P = .003), excess estrogen state (P = .002), indwelling central venous line (P < .001), and prior PE and/or deep venous thrombosis (P < .001), were found to be significant independent risk factors for PE. With use of two or more risk factors as the clinical threshold, the sensitivity of a positive PE result was 89% (32 of 36 patients), and the specificity was 94% (180 of 191 patients). CONCLUSION: It is unlikely for CT pulmonary angiography results to be positive for PE in children with no thromboembolic risk factors. The use of risk factor assessment as a first-line triage tool has the potential to guide more appropriate use of CT pulmonary angiography in children, with associated reductions in radiation exposure and costs.

Aprepitant pharmacokinetics and assessing the impact of aprepitant on cyclophosphamide metabolism in cancer patients undergoing hematopoietic stem cell transplantation.

Aprepitant, a neurokinin antagonist, is an effective antiemetic agent in chemotherapy for delayed nausea and vomiting. The study objective was to evaluate the pharmacokinetics of aprepitant and concurrent cyclophosphamide (CY), often a component of hematopoietic stem cell transplant (HSCT) conditioning regimen, in cancer patients undergoing HSCT. Forty subjects were randomized to either aprepitant or placebo in addition to standard antiemetics. Aprepitant or placebo was started 1 hour before the first chemotherapy or radiation dose for HSCT conditioning and administered daily until 4 days after infusion of the hematopoietic cell graft (for a total of 10-12 days). Serial blood samples were collected for aprepitant and CY plus 2 important CY metabolites. The results indicate that aprepitant is well absorbed and does not auto-induce its metabolism. No significant drug interaction was observed with CY or its metabolites. A significant portion of the patients had subtherapeutic aprepitant concentrations; however, chemotherapy-induced nausea and vomiting were effectively managed. No dosage adjustment was necessary, and administration of aprepitant in HSCT at the prescribed dosage of 125 mg orally on day 1 and 80 mg orally on each consecutive day through day +4 after HSCT was well tolerated with no significant changes in CY pharmacokinetic parameters.

Ruthenium-catalyzed regioselective deuteration of alcohols at the ß-carbon position with deuterium oxide.

A convenient method for regioselective H/D exchange between D(2)O and alcohols at the ß-carbon position using the catalytic system [(p-cymene)RuCl(2)]/ethanolamine/KOH is described. This method is applicable for deuteration of both primary and secondary alcohols. The H/D exchange reactions proceed through an oxidation/modification/reduction reaction sequence. Alcohols are first temporarily oxidized to carbonyl compounds by the hydrogen transfer catalyst. The carbonyl compounds then undergo deuteration at the carbon adjacent to the carbonyl group by keto-enol tautomerization in the presence of D(2)O and a catalytic amount of base. The deuterated carbonyl compounds are then reduced to produce deuterated alcohols. In support of the reaction mechanism, a well-defined bimetallic ruthenium complex was isolated from the reaction of [{(p-cymene)RuCl(2)}(2)] with ethanolamine. The activity of this complex is similar to that of [{(p-cymene)RuCl(2)}(2)]/ethanolamine.