Atrial placement of Aveir-VR leadless pacemaker in a patient with complex cardiac anatomy.

Leadless pacemakers have provided new treatment modalities that can be especially useful in patients with complex cardiac anatomy and contraindications toward other pacemaker approaches. The Aveir™ single-chamber (VR) leadless pacemaker (LP) (Abbott Laboratories, Chicago, IL) is a recently approved device that can be placed in the right ventricle for patients with bradycardia. In this case, we present a novel use for the device through placement in the atrium to control atrial flutter in a patient with a hypoplastic right ventricle.

Ir(III) Half-Sandwich Photosensitizers with a π-Expansive Ligand for Efficient Anticancer Photodynamic Therapy.

One approach to reduce the side effects of chemotherapy in cancer treatment is photodynamic therapy (PDT), which allows spatiotemporal control of the cytotoxicity. We have used the strategy of coordinating π-expansive ligands to increase the excited state lifetimes of Ir(III) half-sandwich complexes in order to facilitate the generation of 1O2. We have obtained derivatives of formulas [Cp*Ir(C∧N)Cl] and [Cp*Ir(C∧N)L]BF4 with different degrees of π-expansion in the C∧N ligands. Complexes with the more π-expansive ligand are very effective photosensitizers with phototoxic indexes PI > 2000. Furthermore, PI values of 63 were achieved with red light. Time-dependent density functional theory (TD-DFT) calculations nicely explain the effect of the π-expansion. The complexes produce reactive oxygen species (ROS) at the cellular level, causing mitochondrial membrane depolarization, cleavage of DNA, nicotinamide adenine dinucleotide (NADH) oxidation, as well as lysosomal damage. Consequently, cell death by apoptosis and secondary necrosis is activated. Thus, we describe the first class of half-sandwich iridium cyclometalated complexes active in PDT.

In situ enzymatic generation of Au/Pt nanoparticles as an analytical photometric system: proof of concept determination of tyramine.

In situ enzymatic generation of bimetallic nanoparticles, mainly Au/Pt, overcomes the drawbacks (continuous absorbance drift, modest LOQ, and long-time reaction) observed when AuNP alone are produced. In this study, Au/Pt nanoparticles have been characterized by EDS, XPS, and HRTEM images using the enzymatic determination of tyramine with tyramine oxidase (TAO) as a model. Under experimental conditions, the Au/Pt NPs show an absorption maximum at 580 nm which can be related to the concentration of tyramine in the range 1.0 × 10-6M to 2.5 × 10-4M with a RSD of 3.4% (n = 5, using 5 × 10-6M tyramine). The Au/Pt system enables low LOQ (1.0 × 10-6 M), high reduction of the absorbance drift, and a significant shortening of the reaction time (i.e., from 30 to 2 min for a [tyramine] = 1 × 10-4M); additionally, a better selectivity is also obtained. The method has been applied to tyramine determination in cured cheese and no significant differences were obtained compared to a reference method (HRP:TMB). The effect of Pt(II) seems to involve the previous reduction of Au(III) to Au(I) and NP generation from this oxidation state. Finally, a three-step (nucleation-growth-aggregation) kinetic model for the generation of NPs is proposed; this has enabled us to obtain a mathematical equation which explains the experimentally observed variation of the absorbance with time.

Enzymatically mediated fluorescent copper nanocluster generation for tyramine determination.

This work details the enzymatic generation of fluorescence nanomaterials and the use of this optical signal as the analytical parameter for the quantification of the substrate. More specifically, fluorescent copper nanoclusters have been obtained during the enzymatic reaction of tyramine oxidase and tyramine in the presence of Cu(II); the fluorescence intensity being proportional to the concentration of tyramine. The nanoclusters obtained show fluorescence at 445 nm by being excited at 320 nm and have been characterized by TEM, EDX, and XPS. The formation mechanism has also been studied, suggesting that under the optimal conditions (0.1 M MES buffer and pH = 6), the formation of the nanoclusters is due to the reducing properties of the product of the enzymatic reaction (p-hydroxybenzaldehyde) in MES buffer. The method shows a linear relationship with the concentration of tyramine in the range from 1.0·10-5 to 2.5·10-4 M, a RSD of 3% (n = 5) and a LOD of 6.3·10-6 M. The method has been applied to the determination of tyramine in sausage with good results.

Selective generation of gold nanostructures mediated by flavo-enzymes to develop optical biosensors.

This paper explores, for the first time, the use of flavo-enzymes for the enzymatic generation of gold nanomaterials. It has been demonstrated that when the oxidation of glucose by GOx is carried out in the presence of Au(III), the in-situ formation of gold nanomaterials is observed. Moreover, depending on the experimental conditions, either nanoparticles (AuNPs) or nanoclusters (AuNCs) are better observed, whose spectroscopical properties can be related to the concentration of glucose. Working at pH 6, only AuNCs with fluorescence at 420 nm (λex=335 nm) are obtained (linear relationship from 6.0·10-5 M to 1.5·10-3 M glucose). However, when the enzymatic reaction is performed at pH 8, AuNPs (λmax=580 nm) are also obtained (linear relationship from 5.5·10-4 M to 2.0·10-3 M glucose). Mathematical equations describing the variation of fluorescence and absorbance values during the reaction have been proposed. The results obtained suggest that AuNCs are formed using GOx as nucleation seeds. Since AuNPs belong to the branched-type, it is suggested that they are obtained by AuNC coalescence. From these models the AuNP molar absorptivity per atom was obtained (2.0(±0.3)·103 M-1cm-1). Finally, the method has been applied to the determination of glucose in orange juice and human plasma samples. Comparing the results with the GOx/HRP/TMB method and a commercial glucometer, no significant differences (P=0.05) are obtained.

Combating Child Summer Food Insecurity: Examination of a Community-Based Mobile Meal Program.

Low-income children's access to meals decreases during the summer months due to losing the benefit of the free and reduced-price lunches they normally receive during the school year. Few studies critically examine community-based approaches to providing summer meals. This mixed methods study examined a mobile meal program implemented in a community with large economic disparities. Parents and caregivers who attended the mobile meal program with a child at one of three sites completed surveys that screened for risk of food insecurity and examined access and utilization of community food resources. Interviews with a representative subsample of English- and Spanish-speaking participants elicited an in-depth understanding of food insecurity in the community and perspectives on the mobile meal program. Surveys (n = 284) were completed in English (78%) and Spanish (22%). Participants identified primarily as Asian (32%), Latino/Hispanic (29%), and White (27%), with 26% screening positive for risk of food insecurity within the past 12 months. Qualitative interviews (n = 36) revealed widespread support for meals served in public settings as they were perceived to be welcoming, fostered social interactions, and helped the community at large. Participants described the high cost of living as a key motivation for participating and cited immigration fears as a barrier to accessing public resources. Findings from this study suggest the importance of innovative community-based approaches to serving hard-to-reach children during the summer.

Deep venous thrombosis and pulmonary embolisms in adult patients undergoing craniotomy for brain tumors.

OBJECTIVE: The development of venothromboembolisms (VTEs), including deep vein thrombosis (DVT) and pulmonary emboli (PE), is common in brain tumor patients. Their development can be catastrophic. Studies evaluating pre-operative clinical factors that predispose patients to the development of VTE are few and limited. An understanding may help risk stratify patients and guide subsequent therapy aimed at reducing the risk of DVTs/PEs. METHODS: All adult patients who underwent surgery for an intracranial tumor at an academic tertiary care institution between 1998 and 2008 were retrospectively reviewed. Stepwise multivariate logistical regression analysis was used to identify pre-operative factors associated with the development of peri-operative (within 30 days of surgery) DVTs/PEs among patients who underwent surgery of their intracranial tumor. RESULTS: Of the 4293 patients in this study, 126 (3%) patients developed DVT and/or PE in the peri-operative period. The pre-operative factors independently associated with the development of DVTs/PEs were: poorer Karnofsky performance scale (KPS) [odds ratio (OR), 1·040; 95% confidence interval (CI), 1·026-1·052; P<0·0001], high grade glioma (OR, 1·702; 95% CI, 1·176-2·465; P = 0·005), older age (OR, 1·033; 95% CI, 1·020-1·046; P<0·0001), hypertension (OR, 1·785; 95% CI, 1·180-2·699; P = 0·006), and motor deficit (OR, 1·854; 95% CI, 1·244-2·763; P = 0·002). Eighty six per cent of the patients with DVTs/PEs were treated with either unfractionated or low molecular weight heparin, and 4% of these patients developed intracranial hemorrhage. DISCUSSION: The present study found that poorer functional status, older age, pre-operative motor deficit, high grade glioma, and hypertension each independently increased the risk of developing peri-operative DVTs/PEs. These findings may provide patients and physicians with prognostic information that may guide therapies aimed at minimizing the development of peri-operative DVTs/PEs.