Structural Features and Properties' Characterization of Polylactic Acid/Natural Rubber Blends with Epoxidized Soybean Oil.

Because of the effort to preserve petroleum resources and promote the development of eco-friendly materials, bio-based polymers produced from sustainable resources have attracted great attention. Among them, polylactide (PLA) and natural rubber (NR) present prominent polymers with unique barrier and mechanical features. A series of samples with improved phase compatibility were obtained by blending PLA and NR using a double-rotor mixer. A plasticizing and enhancing effect on the polymers' compatibility was achieved by using epoxidized soybean oil (ESO) as a natural plasticizer and compatibilizer. ESO compounding in the PLA-NR blends increased the mobility of the biopolymer's molecular chains and improved the thermal stability of the novel material. The size of the NR domains embedded in the continuous PLA matrix decreased with the ESO content increment. The combination of thermal analysis and scanning electron microscopy enabled the authors to determine the features of potential packaging material and the optimal content of PLA-NR-ESO for the best mechanical properties.

Improving the Power of the American Society of Anesthesiology Classification System to Risk Stratify Vascular Surgery Patients Based on National Surgical Quality Improvement Project-Defined Functional Status.

BACKGROUND: Recently published reports have shown that the American Society of Anesthesiology (ASA) classification system has limited applicability in vascular surgery patients. Most patients undergoing vascular procedures are designated as ASA class III, limiting discrimination in preoperative risk assessment. The 2006 National Surgical Quality Improvement Project (NSQIP), containing over 170,000 surgical cases, demonstrated that functional status is an important predictor of mortality. We propose that dividing ASA class III into 2 subgroups, based on NSQIP-defined functional status, improves the predictive value of the ASA scheme. METHODS: The 2006 NSQIP database was queried for ASA class III patients undergoing vascular surgery procedures. Patients were divided into groups IIIA and IIIB based on independent or dependent (partial or complete) functional status, respectively. Difference in 30-day survival between subgroups was evaluated using Kaplan-Meier and logistic regression analyses. Differences in postoperative morbidity and length of stay were compared using the unpaired t-test. RESULTS: ASA class III patients having undergone vascular surgery procedures numbered 11,555 (68%). Of those 9,913 (85.7%) patients were independent (IIIA), and 1,642 (14.3%) were dependent (IIIB). Mean 30-day mortality was 1.3% in subgroup IIIA, and 6.5% in IIIB (logrank P < 0.001, χ2, 137.8). Mean lengths of stay between subgroups IIIA and IIIB were 5.4 and 13.2 days (P < 0.001). The risk of NSQIP-defined postoperative complications was 0.16 in IIIA and 0.32 in IIIB (P < 0.001). CONCLUSIONS: A 5-fold difference in mortality was observed between patients who were functionally independent and dependent. A significant increase in length of stay and incidence of postoperative complications was also observed in subgroup IIIB. Subdividing ASA class III vascular surgery patients markedly improves the value of the ASA classification system. Given the "high-risk" nature of patients with vascular disease, the addition of functional status to the preoperative assessment will assist in predicting outcomes in this patient population.

Insertional Mutagenesis Confounds the Mechanism of the Morbid Phenotype of a PLNR9C Transgenic Mouse Line.

BACKGROUND: A mouse line with heterozygous transgenic expression of phospholamban carrying a substitution of cysteine for arginine 9 (TgPLNR9C) under the control of α-myosin heavy chain (αMHC) promoter features dilated cardiomyopathy, heart failure, and premature death. METHODS AND RESULTS: Determination of transgene chromosomal localization by conventional methods shows that in this line the transgenic array of 13 PLNR9C expression cassettes, arranged in a head-to-tail tandem orientation, have integrated into the bidirectional promoter of the αMHC (Myh6) gene and the gene for the regulatory noncoding RNA Myheart (Mhrt), both of which are known to be involved in cardiac development and pathology. Expression of the noncoding RNA Mhrt in TgPLNR9C mice exhibits profound deregulation, despite the presence of the second, intact allele. CONCLUSIONS: The TgPLNR9C mouse strain is, in the best case, a functionally ambiguous phenocopy of the human PLNR9C heterozygote, because a similar constellation of genetically programmed events can not occur in a patient. Publications featuring "cardiac-specific overexpression" are focused on the phenotype and typically forgo the definition of the transgene integration site or transgene temporal expression profile, so caution should be exercised in attributing clinical relevance to pathologic phenomena observed in αMHC-driven transgenes.

Analyzing Risk Factors for Morbidity and Mortality after Lung Resection for Lung Cancer Using the NSQIP Database.

BACKGROUND: Our goal was to develop a predictive model that identifies how preoperative risk factors and perioperative complications lead to mortality after anatomic pulmonary resections. STUDY DESIGN: This was a retrospective cohort study. The American College of Surgeons NSQIP database was examined for all patients undergoing elective lobectomies for cancer from 2005 through 2012. Fifty-eight pre- and intraoperative risk factors and 13 complications were considered for their impact on perioperative mortality within 30 days of surgery. Multivariate logistic regression and a logistic regression model using least absolute shrinkage and selection operator (LASSO) selection methods were used to identify preoperative risk factors that were significant for predicting mortality, either through or independent of complications. Only factors that were significant under both the multivariate logistic regression and LASSO-selected models were considered to be validated for the final model. RESULTS: There were 6,435 lobectomies identified. After multivariate logistic regression modeling, 28 risk factors and 5 complications were found to be predictors for mortality. This was then tested against the LASSO method. There were 7 factors shared between the LASSO and multivariate logistic regressions that predicted mortality based on comorbidity: age (p = 0.007), male sex (p = 0.011), open lobectomy (p = 0.001), preoperative dyspnea at rest (p < 0.001), preoperative dyspnea on exertion (p = 0.003), preoperative dysnatremia (serum sodium <135 mEq/L or >145 mEq/L) (p = 0.011), and preoperative anemia (p = 0.002). Of these, 3 variables predicted mortality independent of any complications: dyspnea at rest, dyspnea on exertion, and dysnatremia. CONCLUSIONS: The clinical factors that predict postoperative complications and mortality are multiple and not necessarily aligned. Efforts to improve quality after anatomic pulmonary resections should focus on mechanisms to address both types of adverse outcomes.

Parallel universes of Black Six biology.

UNLABELLED: Creation of lethal and synthetic lethal mutations in an experimental organism is a cornerstone of genetic dissection of gene function, and is related to the concept of an essential gene. Common inbred mouse strains carry background mutations, which can act as genetic modifiers, interfering with the assignment of gene essentiality. The inbred strain C57BL/6J, commonly known as "Black Six", stands out, as it carries a spontaneous homozygous deletion in the nicotinamide nucleotide transhydrogenase (Nnt) gene [GenBank: AH009385.2], resulting in impairment of steroidogenic mitochondria of the adrenal gland, and a multitude of indirect modifier effects, coming from alteration of glucocorticoid-regulated processes. Over time, the popular strain has been used, by means of gene targeting technology, to assign "essential" and "redundant" qualifiers to numerous genes, thus creating an internally consistent "parallel universe" of knowledge. It is unrealistic to suggest phasing-out of this strain, given the scope of shared resources built around it, however, continuing on the road of "strain-unawareness" will result in profound waste of effort, particularly where translational research is concerned. The review analyzes the historical roots of this phenomenon and proposes that building of "parallel universes" should be urgently made visible to a critical reader by obligatory use of unambiguous and persistent tags in publications and databases, such as hypertext links, pointing to a vendor's strain description web page, or to a digital object identifier (d.o.i.) of the original publication, so that any research done exclusively in C57BL/6J, could be easily identified. REVIEWERS: This article was reviewed by Dr. Neil Smalheiser and Dr. Miguel Andrade-Navarro.

CASQ1 gene is an unlikely candidate for malignant hyperthermia susceptibility in the North American population.

BACKGROUND: Malignant hyperthermia (MH, MIM# 145600) is a complex pharmacogenetic disorder that is manifested in predisposed individuals as a potentially lethal reaction to volatile anesthetics and depolarizing muscle relaxants. Studies of CASQ1-null mice have shown that CASQ1, encoding calsequestrin 1, the major Ca2+ binding protein in the lumen of the sarcoplasmic reticulum, is a candidate gene for MH in mice. The aim of this study was to establish whether the CASQ1 gene is associated with MH in the North American population. METHODS: The entire coding region of CASQ1 in 75 unrelated patients diagnosed by caffeine-halothane contracture test as MH susceptible (MHS) was analyzed by DNA sequencing. Subsequently, three groups of unrelated individuals (130 MHS, 100 MH negative, and 192 normal controls) were genotyped for a variant that was identified by sequencing. Levels of CASQ1 expression in the muscle from unrelated MHS and MH negative individuals were estimated by Western blotting. RESULTS: Screening of the entire coding sequence of the CASQ1 gene in 75 MHS patients revealed a single variant c.260T > C (p.Met87Thr) in exon 1. This variant is unlikely to be pathogenic, because its allele frequency in the MHS group was not significantly different from that of controls. There was also no difference in calsequestrin 1 protein levels between muscle samples from MHS and controls, including those carrying the p.Met87Thr variant. CONCLUSIONS: This study revealed a low level of protein coding sequence variability within the human CASQ1 gene, indicating that CASQ1 is not a major MHS locus in the North American population.

Novel excitation-contraction uncoupled RYR1 mutations in patients with central core disease.

Central core disease, one of the most common congenital myopathies in humans, has been linked to mutations in the RYR1 gene encoding the Ca(2+) release channel of the sarcoplasmic reticulum (RyR1). Functional analyses showed that disease-associated RYR1 mutations led to impairment of skeletal muscle Ca(2+) homeostasis; however, thorough understanding of the molecular mechanisms underlying central core disease and other RyR1-related conditions is still lacking. We screened by sequencing the complete RYR1 transcripts in ten unrelated patients with central core disease and identified five novel, p.M4640R, p.L4647P, p.F4808L, p.D4918N and p.F4941C, and four recurrent mutations. Four of the novel mutations involved amino acid residues that were positioned within putative transmembrane segments of the RyR1. The pathogenic character of the identified mutations was demonstrated by bioinformatic analyses and by the in vitro functional studies in HEK293 cells and RYR1-null (dyspedic) myotubes. Characterization of Ca(2+) channel properties of RyR1s carrying one recurrent and two novel mutations upholds the view that diminished intracellular Ca(2+) release caused by impaired Ca(2+) channel gating and/or Ca(2+) permeability is an important component of central core disease etiology. This study expands the list of functionally characterized disease-associated RyR1 mutations, increasing the value of genetic diagnosis for RyR1-related disorders.

A fluorodeoxyglucose avid mediastinal parathyroid adenoma masquerading as metastatic bladder cancer.

A 64-year old male with a prior medical history of bladder transitional cell carcinoma treated with a cystoprostatectomy and adjuvant platinum-based chemotherapy 10 years earlier underwent a surveillance positron emission tomography (PET) scan that revealed a metabolically active 2-cm nodule in the superior mediastinum, anterior to the origin of the innominate artery. The lesion was removed due to concerns of metastatic disease using a cervical mediastinoscope. Final pathology revealed an ectopic mediastinal parathyroid adenoma. The combination of the rare presentation, uncommon surgical approach and pathology makes this case unique.

Spontaneous axillary artery aneurysm: a case report and review of the literature.

Degenerative arterial aneurysms can occur in any vascular territory. However, they are exceedingly rare in the axillary artery. Complications of axillary artery aneurysms may result in acute vascular insufficiency and neurological deficits. Prompt treatment should be employed in the management of this condition. We report a case of an atraumatic degenerative axillary artery aneurysm that was treated with transaxillary open surgical bypass.

Acute aortic occlusion from a Candida fungus ball.

Fungal arterial infections are well-described entities resulting in direct invasion of the arterial wall or embolic occlusion of small and medium-sized arteries. However, acute occlusion of large vessels such as the aorta by fungal material is exceedingly rare. A 53-year-old woman presented with acute bilateral lower extremity ischemia. She had a history of fungal endocarditis requiring two prosthetic mitral valve replacements; the last episode was 7 months before the current admission. Imaging studies revealed that she had an acute infrarenal aortic occlusion, with evidence of multiple end-organ emboli. After transfemoral thromboembolectomy, perfusion was restored to her lower extremities with minor neurologic sequelae. She ultimately responded to intravenous antifungal agents.

Ryanodine receptor type 1 gene mutations found in the Canadian malignant hyperthermia population.

PURPOSE: Malignant hyperthermia (MH) is an autosomal dominant pharmacogenetic disorder that is manifested on exposure of susceptible individuals to halogenated anesthetics or succinylcholine. Since MH is associated primarily with mutations in the ryanodine receptor type 1 (RYR1) gene, the purpose of this study was to determine the distribution and frequency of MH causative RyR1 mutations in the Canadian MH susceptible (MHS) population. METHODS: In this study, we screened a representative cohort of 36 unrelated Canadian MHS individuals for RYR1 mutations by sequencing complete RYR1 transcripts and selected regions of CACNA1S transcripts. We then analyzed the correlation between caffeine-halothane contracture test (CHCT) results and RYR1 genotypes within MH families. RESULTS: Eighty-six percent of patients had at least one RyR1 mutation (31 out of 36), five of which were unrelated individuals who were double-variant carriers. Fifteen of the 27 mutations identified in RYR1 were novel. Eight novel mutations, involving highly conserved amino acid residues, were predicted to be causal. Two of the mutations co-segregated with the MHS phenotype within two large independent families (a total of 79 individuals). Fourteen percent of MHS individuals (five out of 36) carried neither RYR1 nor known CACNA1S mutations. CONCLUSIONS: The distribution and frequency of MH causative RyR1 mutations in the Canadian MHS population are close to those of European MHS populations. Novel mutations described in this study will contribute to the worldwide pool of MH-associated mutations in the RYR1 gene, ultimately increasing the value of MH genetic diagnostic testing.

Ca2+ dysregulation in Ryr1(I4895T/wt) mice causes congenital myopathy with progressive formation of minicores, cores, and nemaline rods.

Ryr1(I4895T/wt) (IT/+) mice express a knockin mutation corresponding to the human I4898T EC-uncoupling mutation in the type 1 ryanodine receptor/Ca(2+) release channel (RyR1), which causes a severe form of central core disease (CCD). IT/+ mice exhibit a slowly progressive congenital myopathy, with neonatal respiratory stress, skeletal muscle weakness, impaired mobility, dorsal kyphosis, and hind limb paralysis. Lesions observed in myofibers from diseased mice undergo age-dependent transformation from minicores to cores and nemaline rods. Early ultrastructural abnormalities include sarcomeric misalignment, Z-line streaming, focal loss of cross-striations, and myofibrillar splitting and intermingling that may arise from defective myofibrillogenesis. However, manifestation of the disease phenotype is highly variable on a Sv129 genomic background. Quantitative RT-PCR shows an equimolar ratio of WT and mutant Ryr1 transcripts within IT/+ myofibers and total RyR1 protein expression levels are normal. We propose a unifying theory in which the cause of core formation lies in functional heterogeneity among RyR1 tetramers. Random combinations of normal and either leaky or EC-uncoupled RyR subunits would lead to spatial differences in Ca(2+) transients; the resulting heterogeneity of contraction among myofibrils would lead to focal, irreversible tearing and shearing, which would, over time, enlarge to form minicores, cores, and nemaline rods. The IT/+ mouse line is proposed to be a valid model of RyR1-related congenital myopathy, offering high potential for elucidation of the pathogenesis of skeletal muscle disorders arising from impaired EC coupling.

beta-adrenergic regulation of a novel isoform of NCX: sequence and expression of shark heart NCX in human kidney cells.

The function, regulation, and molecular structure of the cardiac Na(+)/Ca(2+) exchangers (NCXs) vary significantly among vertebrates. We previously reported that beta-adrenergic suppression of amphibian cardiac NCX1.1 is associated with specific molecular motifs. Here we investigated the bimodal, cAMP-dependent regulation of spiny dogfish shark (Squalus acanthias) cardiac NCX, exploring the effects of molecular structure, host cell environment, and ionic milieu. The shark cardiac NCX sequence (GenBank accession no. DQ 068478) revealed two novel proline/alanine-rich amino acid insertions. Wild-type and mutant shark NCXs were cloned and expressed in mammalian cells (HEK-293 and FlpIn-293), where their activities were measured as Ni(2+)-sensitive Ca(2+) fluxes (fluo 4) and membrane (Na(+)/Ca(2+) exchange) currents evoked by changes in extracellular Na(+) concentration and/or membrane potential. Regardless of Ca(2+) buffering, beta-adrenergic stimulation of cloned wild-type shark NCX consistently produced bimodal regulation (defined as differential regulation of Ca(2+)-efflux and -influx pathways), with suppression of the Ca(2+)-influx mode and either no change or enhancement of the Ca(2+)-efflux mode, closely resembling results from parallel experiments with native shark cardiomyocytes. In contrast, mutant shark NCX, with deletion of the novel region 2 insertion, produced equal suppression of the inward and outward currents and Ca(2+) fluxes, thereby abolishing the bimodal nature of the regulation. Control experiments with nontransfected and dog cardiac NCX-expressing cells showed no cAMP regulation. We conclude that bimodal beta-adrenergic regulation is retained in cloned shark NCX and is dependent on the shark's unique molecular motifs.

Postoperative hyperbilirubinemia is an independent predictor of longterm outcomes after cardiopulmonary bypass.

BACKGROUND: Two decade-old studies of cardiopulmonary bypass (CPB) patients documented a 25% to 35% incidence of postoperative hyperbilirubinemia, associated with increased in-hospital morbidity and mortality. Longterm consequences of this complication are unknown. STUDY DESIGN: Medical records of CPB patients were reviewed. Mortality was ascertained through the National Death Index. Proportional hazards determined important factors in post-CPB survival. Logistic regression delineated predictors of hyperbilirubinemia. Kaplan-Meier and Mantel-Cox log-rank survival analyses compared hyperbilirubinemia groups. RESULTS: Bilirubin levels were followed in 826 (59.7%) patients. Bilirubin was normal in 570 (69.0%) patients (group 1), it was 1.4 to 2.8 mg/dL in 184 (22.3%) patients (group 2), and it exceeded 2.8 mg/dL in 72 (8.7%) patients (group 3). Elevated bilirubin was associated with decreased body mass index, congestive heart failure, heparin before operation, postoperative transfusion requirement, bleeding, and renal failure. In-hospital mortality was 4.3% in group 2 and 25.0% in group 3, compared with 0.9% in group 1 (p<0.001). Two-year crude survival was 95.8% in group 1, 84.8% in group 2, and 62.5% in group 3 (p<0.001). Multivariable predictors of longterm mortality were older age, history of stroke, emergency operation, increased duration of cardiopulmonary bypass, respiratory failure, and elevated bilirubin. Compared with survival in group 1, there was a 1.7-fold decrease in group 2 2-year survival (95% CI 0.9 to 3.0; p=0.09) and a 3.8-fold decrease in group 3 survival (95% CI 2.0 to 7.2; p<0.001). CONCLUSIONS: Postoperative bilirubin elevation in CPB patients is common and deadly. The predictive power of hyperbilirubinemia is similar to that of respiratory failure. The cause of postbypass hyperbilirubinemia is unknown and is probably multifactorial. Additional prospective studies are warranted.

An Ryr1I4895T mutation abolishes Ca2+ release channel function and delays development in homozygous offspring of a mutant mouse line.

A heterozygous Ile4898 to Thr (I4898T) mutation in the human type 1 ryanodine receptor/Ca(2+) release channel (RyR1) leads to a severe form of central core disease. We created a mouse line in which the corresponding Ryr1(I4895T) mutation was introduced by using a "knockin" protocol. The heterozygote does not exhibit an overt disease phenotype, but homozygous (IT/IT) mice are paralyzed and die perinatally, apparently because of asphyxia. Histological analysis shows that IT/IT mice have greatly reduced and amorphous skeletal muscle. Myotubes are small, nuclei remain central, myofibrils are disarranged, and no cross striation is obvious. Many areas indicate probable degeneration, with shortened myotubes containing central stacks of pyknotic nuclei. Other manifestations of a delay in completion of late stages of embryogenesis include growth retardation and marked delay in ossification, dermatogenesis, and cardiovascular development. Electron microscopy of IT/IT muscle demonstrates appropriate targeting and positioning of RyR1 at triad junctions and a normal organization of dihydropyridine receptor (DHPR) complexes into RyR1-associated tetrads. Functional studies carried out in cultured IT/IT myotubes show that ligand-induced and DHPR-activated RyR1 Ca(2+) release is absent, although retrograde enhancement of DHPR Ca(2+) conductance is retained. IT/IT mice, in which RyR1-mediated Ca(2+) release is abolished without altering the formation of the junctional DHPR-RyR1 macromolecular complex, provide a valuable model for elucidation of the role of RyR1-mediated Ca(2+) signaling in mammalian embryogenesis.

Wedge resection vs lobectomy: 10-year survival in stage I primary lung cancer.

BACKGROUND: The selection of lobectomy or wedge resection in the treatment of patients with stage I primary lung cancer remains controversial. Clinical judgment based on comorbidities remains the main decision factor. We investigated the impact of procedure on long-term survival in a multicenter retrospective analysis. METHODS: The records of 289 patients who underwent surgical resection of stage I primary lung cancer between 1993 and 1998 at three tertiary medical centers were reviewed for age, sex, type of resection, tumor size, number of lymph nodes dissected, pathology, and recurrence. Long-term survival was obtained through the Federal Social Security Death Index and Cancer Registries. Kaplan-Meier, Wilcox, logistic regression, and power and t test analyses were used to examine survival, predictors of mortality, and correlations. RESULTS: A total of 215 patients underwent lobectomy, and 74 underwent wedge resection. The groups were similar with respect to age, tumor size, and other comorbidities. Overall, there was a nonsignificant trend toward better survival times in patients after lobectomy vs wedge resection (mean [+/- SD] survival time, 5.8 +/- 0.3 vs 4.1 +/- 0.3 years, respectively; p = 0.112). This trend gained significance in smaller cancers, where patients who underwent lobectomy for tumors < 3 cm in size had better survival times compared to those who underwent wedge resection (p = 0.029). CONCLUSION: Although the overall difference in survival time between patients undergoing lobectomy and those undergoing wedge resection was not significant, patients with tumors < 3 cm in size had improved survival times after undergoing lobectomy. Thus, tumor size appears to be an important factor to be considered in preoperative planning. Randomized trials are necessary to confirm the superiority of lobectomy over wedge resection for stage IA lung cancers.