Formal [4 + 2] Cycloadditions of Maleimides on Duplex DNA.

Near-quantitative DNA bioconjugation and detailed mechanistic investigations of reactions involving 5-(vinyl)-2'-deoxyuridine (VdU) and maleimides are reported. According to accelerated reaction rates in solvents with increasing polarity and trends in product stereochemistry, VdU-maleimide reactions proceed via a formal [4 + 2] stepwise cycloaddition. In contrast, 5-(1,3-butadienyl)-2'-deoxyuridine (BDdU) reacts with maleimides in a concerted [4 + 2] Diels-Alder cycloaddition. VdU-maleimide reactions enable high-yielding bioconjugation of duplex DNA in vitro (>90%) as well as metabolic labeling experiments in cells.

A Bright and Ionizable Cytosine Mimic for i-Motif Structures.

A new fluorescent cytosine analog "tsC" containing a trans-stilbene moiety was synthesized and incorporated into hemiprotonated base pairs that comprise i-motif structures. Unlike previously reported fluorescent base analogs, tsC mimics the acid-base properties of cytosine (pKa ≈ 4.3) while exhibiting bright (ε × Φ ≈ 1000 cm-1 M-1) and red-shifted fluorescence (λem = 440 → 490 nm) upon its protonation in the water-excluded interface of tsC+:C base pairs. Ratiometric analyses of tsC emission wavelengths facilitate real-time tracking of reversible conversions between single-stranded, double-stranded, and i-motif structures derived from the human telomeric repeat sequence. Comparisons between local changes in tsC protonation with global structure changes according to circular dichroism suggest partial formation of hemiprotonated base pairs in the absence of global i-motif structures at pH = 6.0. In addition to providing a highly fluorescent and ionizable cytosine analog, these results suggest that hemiprotonated C+:C base pairs can form in partially folded single-stranded DNA in the absence of global i-motif structures.

Novel Therapies for Critical Limb-Threatening Ischemia.

PURPOSE OF REVIEW: This review intends to discuss the latest endovascular and surgical advancement in the treatment of critical limb-threatening ischemia (CLTI). RECENT FINDINGS: We discuss novel endovascular technological advancements such as intravascular lithotripsy, the Tack endovascular stent, the PQ Bypass DETOUR system, and the LimFlow System for deep venous arterialization (DVA) in the very high risk "no-option" CLTI population. We also discuss the increasing adoption of radial and pedal approaches for endovascular revascularization and the tibiopedal arterial minimally invasive (TAMI) technique. On the surgical front, we discuss the distal vein patch technique and surgical and hybrid DVA. Recent advancements in the treatment options of CLTI will likely lead to reducing the rate of major amputations if they are adopted in a collaborative environment in order to apply the most appropriate treatment option to each individual patient based on the anatomy, comorbidities, functional status, and local expertise.

A Highly Fluorescent Nucleobase Molecular Rotor.

Fluorescent base analogs (FBAs) are powerful probes of nucleic acids' structures and dynamics. However, previously reported FBAs exhibit relatively low brightness and therefore limited sensitivity of detection. Here we report the hitherto brightest FBA that has ideal molecular rotor properties for detecting local dynamic motions associated with base pair mismatches. The new trans-stilbene annulated uracil derivative "tsT" exhibits bright fluorescence emissions in various solvents (ε × Φ = 3400-29 700 cm-1 M-1) and is highly sensitive to mechanical motions in duplex DNA (ε × Φ = 150-4250 cm-1 M-1). tsT is thereby a "smart" thymidine analog, exhibiting a 28-fold brighter fluorescence intensity when base paired with A as compared to T or C. Time-correlated single photon counting revealed that the fluorescence lifetime of tsT (τ = 4-11 ns) was shorter than its anisotropy decay in well-matched duplex DNA (θ = 20 ns), yet longer than the dynamic motions of base pair mismatches (0.1-10 ns). These properties enable unprecedented sensitivity in detecting local dynamics of nucleic acids.

The utility of trough mycophenolic acid levels for the management of lupus nephritis.

Background: Monitoring of mycophenolic acid (MPA) levels may be useful for effective mycophenolate mofetil (MMF) dosing. However, whether commonly obtained trough levels are an acceptable method of surveillance remains debatable. We hypothesized that trough levels of MPA would be a poor predictor of area under the curve (AUC) for MPA. Methods: A total of 51 patients with lupus nephritis who were on MMF 1500 mg twice a day and had a 4-h AUC done were included in this study. MPA levels were measured prior to (C0) and at 1 (C1), 2 (C2) and 4 (C4) h, followed by 1500 mg of MMF. The MPA AUC values were calculated using the linear trapezoidal rule. Regression analysis was used to examine the relationship between the MPA trough and AUC. Differences in the MPA trough and AUC between different clinical and demographic categories were compared using t-tests. Results: When grouped by tertiles there was significant overlap in MPA, AUC 0-4 and MPA trough in all tertiles. Although there was a statistically significant correlation between MPA trough levels and AUC, this association was weak and accounted for only 30% of the variability in MPA trough levels. This relationship might be even more unreliable in men than women. The use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers was associated with increased MPA trough levels and AUC at 0-4 h (AUC0-4). Conclusion: Trough levels of MPA do not show a strong correlation with AUC. In clinical situations where MPA levels are essential to guide therapy, an AUC0-4 would be a better indicator of the adequacy of treatment.

Enzymatic Incorporation of a Coumarin-Guanine Base Pair.

Previous expansions beyond nature's preferred base-pairing interactions have utilized either nonpolar shape-fitting interactions or classical hydrogen bonding. Reported here is a hybrid of these systems. By replacing a single N-H with C-H at a Watson-Crick interface, the design space for new drug candidates and fluorescent nucleobase analogues is dramatically expanded, as demonstrated here by the new, highly fluorescent deoxycytidine mimic 3-glycosyl-5-fluoro-7-methoxy-coumarin-2'-deoxyribose (dCC ). dGTP is selectively incorporated across from a template dCC during enzymatic DNA synthesis. Likewise, dCC is selectively incorporated across from a template guanine when dCC is provided as the triphosphate dCC TP. DNA polymerase I (Klenow fragment) exhibited about a 10-fold higher affinity for dCC TP than dCTP, allowing selective incorporation of dCC in direct competition experiments. These results demonstrate that a single C-H can replace N-H at a Watson-Crick-type interface with preservation of functional selectivity and enhanced activity.

Pulmonary and tricuspid valvuloplasty in carcinoid heart disease.

A 26-year-old female with carcinoid heart disease consisting of severe pulmonary and tricuspid valve stenosis was admitted with line associated sepsis. She recovered from sepsis with antibiotics and aggressive fluid resuscitation but became grossly volume overloaded with evidence of tense ascites and lower extremity edema. She developed worsening renal and hepatic function due to congestive nephropathy and hepatopathy, which did not respond to intravenous diuretics, and she was deemed too sick for surgical pulmonary and tricuspid valve replacement. Pulmonary and tricuspid valvuloplasty was performed as a rescue measure to alleviate her congestive symptoms and improve her candidacy for valve replacement. © 2016 Wiley Periodicals, Inc.

Early and midterm outcomes of transcatheter aortic valve replacement in patients with bicuspid aortic valves.

BACKGROUND: Bicuspid aortic valve (BAV) stenosis has been considered a relative contraindication to transcatheter aortic valve replacement (TAVR). We compared the outcomes of TAVR in patients with BAV stenosis versus patients with trileaflet aortic valve stenosis. METHODS: From March 2012 to September 2017, 727 patients underwent TAVR. Thirty-two patients with BAV were included in this study and compared to 96 patients with comparable risk factors (1:3) with a trileaflet aortic valve (TAV). Transesophageal echocardiography was used to estimate post-TAVR degree of paravalvular leak (PVL). RESULTS: Mean ± standard deviation Society of Thoracic Surgeons risk was 6.01 ± 3.42 in the BAV group and 6.08 ± 3.76 in the TAV group (P = 0.92). Thirty-day mortality was 4.2% (N = 4) in the TAV group and 6.25% (N = 2) in the BAV group (P = 0.63). Three (3.1%) patients in the TAV group and two (6.25%) patients in the BAV group developed a post operative stroke (P = 0.59). Following TAVR, mean aortic valve gradient significantly decreased in both TAV (42.56 ± 14.93 vs 9.27 ± 5.57, P < 0.001) and BAV (44.12 ± 11.82 vs 9.03 ± 7.29, P < 0.001) groups. No patient had a severe PVL after TAVR, and only two (2.08%) patients in the TAV group and one (3.12%) patient in the BAV group had moderate PVL (P = 1.0). Patient survival rate at 1 and 2 years was 86% in the BAV group and 90% at 1 and 2 years in the TAV group (P = 0.74). CONCLUSIONS: TAVR in BAV disease is feasible with favorable valve performance. Immediate and mid-term outcomes of TAVR in patients with BAV are comparable to those with TAV.

Oxidative Heck Reaction as a Tool for Para-selective Olefination of Aniline: A DFT Supported Mechanism.

This study describes the first para-selective palladium-catalyzed alkenylation of tertiary amines. This regioselective C-H activation was conducted without any chelation moieties. A series of olefins were reacted under mild reaction conditions at 60 °C, and the corresponding products were obtained in good yields with high selectivity.

Acute Kidney Injury After Transcatheter Aortic Valve Replacement.

BACKGROUND: Acute kidney injury (AKI) during transcatheter aortic valve replacement (TAVR) increases morbidity and mortality. In this study, we investigated the incidence and risk factors for AKI in patients undergoing TAVR. METHODS: Two hundred ninety consecutive patients underwent TAVR. Valve Academic Research Consortium (VARC)-I criteria for AKI diagnosis at 72 hours, and VARC-II criteria at seven days were employed. RESULTS: Overall AKI incidence was 24.62% (65/264): 50 patients at 72 hours and 15 patients at seven days. Multivariate logistic regression determined transapical (TA) approach (OR: 4.46 [1.37-7.63]), preprocedural glomerular filtration rate less than 45 mL/min (OR: 3.47 [1.35-14.70]), and blood transfusion (OR: 3.34 [1.58-11.09]) as independent predictors for AKI at 72 hours; and prior coronary artery bypass grafting (OR: 3.02 [1.007-9.09]) and peripheral artery disease (PAD) (OR: 3.53 [1.06-11.62]) for AKI at seven days. In-hospital and 30-day mortality was higher in AKI patients. Non-AKI patients' survival was 93% at six months, 89% at 12 months, and 86% at 24 months, whereas survival in AKI at 72 hours was 66% at 6, 12, and 24 months (HR AKI vs. non-AKI: 3.9 [CI: 2.0-7.6]), and survival in AKI at seven days was 64% at 6, 12, and 24 months, HR: 3.13 (CI: 1.42-6.92). For the 12 dialysis patients survival was 82% at 6, 12, and 24 months. CONCLUSIONS: AKI after TAVR is associated with worse outcomes. Blood transfusion should be administered restrictively in TAVR. Patients with CKD, PAD, prior CABG, and TA approach require close surveillance as they are at risk for AKI through seven days after TAVR. doi: 10.1111/jocs.12768 (J Card Surg 2016;31:416-422).

Operative and Mid-Term Outcomes of Thoracic Aortic Operation in Octogenarians and Beyond.

OBJECTIVES: To study the short and mid-term outcomes of thoracic aortic operations in patients ≥80 years old. METHODS: This is a retrospective chart review of patients ≥80 years old who underwent thoracic aortic operation in our institution between 2006 and 2013. RESULTS: Ninety-eight patients were studied. Fifty-four patients underwent open repair; 41 underwent endovascular repair; and three underwent hybrid repair with aortic arch debranching and subsequent endovascular stent graft. Hospital mortality rate among the entire cohort was 11/98 (11%): 7/54 (13%) for open repair; 2/41 (5%) for endovascular repair; and 2/3 (66%) for hybrid repair. Major adverse events occurred in 23/98 (23%) in the entire cohort: 15/54 (28%) in open repair; 5/41 (12%) in endovascular repair; and 3/3 (100%) in hybrid repair. Mean follow-up was 31 ± 28 months (median 26 months). Two- and five-year survival rates were 57%, and 34% for the open approach and 71%, and 43% for the endovascular approach respectively. CONCLUSIONS: Both open and endovascular thoracic aortic repairs can be performed with favorable mortality and perioperative morbidity in appropriately selected octogenarian patients. doi: 10.1111/jocs.12722 (J Card Surg 2016;31:334-340).

Efficacy and Safety of Recombinant Factor VII as Rescue for Severe Perioperative Bleeding in HeartMate II Recipients.

INTRODUCTION: We aimed to study the efficacy and safety of recombinant factor VIIa (rFVIIa) for management of perioperative bleeding in HeartMate II recipients. MATERIALS AND METHODS: Fifty-seven patients underwent HeartMate II implantation. Sixteen patients received rFVIIa (six intraop, eight early postop, and two both intra- and postop). The effect of rFVIIa on transfusion of blood products as well as the amount of chest tube drainage was used to assess efficacy and 30-day incidence of thromboembolic events was used to assess safety. RESULTS: Patients who received intraoperative rFVIIa had been transfused significantly more blood products prior to rFVIIa administration compared to total amount of intraoperatively transfused blood products in those who did not receive intra-op rFVIIa; however, there were no significant differences in the amount of transfused blood products and chest tube output in the 24-hour postoperative period between the two groups. Postoperative administration of rFVIIa did not have a significant impact on the amount of red blood cell transfusion but there was a trend towards decreased requirement for fresh frozen plasma (mean 2.7 vs. 1.1, p = 0.08), platelet (1.5 vs. 0.7, p = 0.14), and cryoprecipitate (5.3 vs. 1.2, p = 0.09). The hourly rate of chest tube output also decreased significantly from an average of 235 ± 57 mL/hour prior to rFVIIa administration to an average of 98 ± 36 mL/hour in the first four hours after rFVIIa administration (p value = 0.003). There were no 30-day thromboembolic events in those patients who received rFVIIa. CONCLUSIONS: This study supports selective use of rFVIIa in HeartMate II recipients for the management of severe perioperative bleeding.

Fluorescent molecular rotors detect O6-methylguanine dynamics and repair in duplex DNA.

Alkylation at the O6 position of guanine is a common and highly mutagenic form of DNA damage. Direct repair of O6-alkylguanines by the "suicide" enzyme O6-methylguanine DNA methyltransferase (MGMT, AGT, AGAT) maintains genome stability and inhibits carcinogenesis. In this study, a fluorescent analogue of thymidine containing trans-stilbene (tsT) is quenched by O6-methylguanine residues in the opposite strand of DNA by molecular dynamics that propagate through the duplex with as much as ∼9 Šof separation. Increased fluorescence of tsT or the cytosine analogue tsC resulting from MGMT-mediated DNA repair were distinguishable from non-covalent DNA-protein binding following protease digest. To our knowledge, this is the first study utilizing molecular rotor base analogues to detect DNA damage and repair activities in duplex DNA.

Speckle tracking echocardiography-determined measures of global and regional left ventricular function correlate with functional capacity in patients with and without preserved ejection fraction.

BACKGROUND: Standard measures of left ventricular systolic and diastolic function often fail to identify left ventricular dysfunction in patients with heart failure and do not correlate with measures of functional capacity. AIM: To determine if speckle tracking echocardiography (STE)-determined measures of global and regional myocardial contractility have a linear association with functional capacity in patients with and without preserved ejection fraction. METHODS: In 68 adult patients, functional status was estimated with the Duke Activity Status Index (DASI), left ventricular ejection fraction was determined with Simpson's biplane method, and QLAB advanced quantification software (Philips, The Netherlands) was used to determine peak measures of strain. RESULTS: Global and regional measures of longitudinal, circumferential, and radial strain had a strong linear association with the DASI score. Longitudinal strain in the inferolateral segments had the strongest correlation with DASI (r = -0.72, P < 0.001). In patients with an ejection fraction ≥45%, ejection fraction and E/e' had no correlation with DASI, whereas longitudinal strain in the inferolateral segments had significant correlation with DASI (r = -0.53, P = 0.03, n = 16). CONCLUSIONS: STE-determined measures of global and regional left ventricular function have a strong linear association with estimates of functional capacity in patients with and without preserved ejection fraction. STE-determined measures of strain, especially longitudinal strain, are likely to be important targets for therapy and should be considered in future studies aimed at improving our diagnosis of left ventricular inadequacy in patients with heart failure, especially those with preserved ejection fraction.

Prevalence and Clinical Characteristics of Low Back Pain among Operating Room Personnel: A Cross-Sectional Study in South of Iran.

Background: Low back pain is one of the most common musculoskeletal disorders and the most common cause of activity restriction in people younger than 45 years. Nurses have a high incidence and prevalence of low back pain in terms of physical and emotional factors among healthcare workers. This study aimed to evaluate the prevalence and clinical characteristics of low back pain. Methods: This cross-sectional study was performed on 385 operating room personnel of the hospitals affiliated with Shiraz (the largest city in southern Iran) University of Medical Sciences. The data were collected via a research-made developed questionnaire. The questionnaire consisted of two parts, including the demographic information and prevalence and dimensions of low back pain. Results: The results showed that the prevalence of low back pain was 74% among operating room personnel. There was a significant relationship among low back pain, education level, and marital status (p < 0.05). Conclusion: Hospital managers should reduce the prevalence of this disorder among operating room staff by teaching preventative patient handling techniques via training courses.

Technical pearls for swine lung transplantation.

BACKGROUND: Since the advent of ex vivo lung perfusion (EVLP), there has been increased focus on swine models of lung transplantation; however, the anatomic differences between human and swine lungs and the technical challenges in performing porcine lung transplantation are not well described in the surgical literature. METHODS: Surgically important anatomic variations are described, and the technical measures taken to address them during harvest and transplantation are introduced. RESULTS: There are three surgically important anatomic variations in pigs. First, the right cranial lobe bronchus arises directly from the trachea, which makes right lung transplantation technically challenging if not prohibitive. Second, the left hemi-azygos vein is fully developed and courses upward through the posterior mediastinum, where it crosses the left pulmonary hilum and drains directly into the coronary sinus. During transplantation, this vein is ligated and dissected away to expose the underlying left pulmonary hilar structures. Third, the right inferior pulmonary vein crosses the midline to drain into the left atrium immediately adjacent to the left inferior pulmonary vein. During donor lung preparation, the right inferior pulmonary vein is ligated distally from the left atrium, which leaves an adequate atrial cuff around the left sided pulmonary veins for later anastomosis. CONCLUSION: Experimental porcine lung transplantation is technically demanding. We have found recognition of the above described anatomical differences and technical nuances facilitate transplantation and provide reproducible results.

Highly diastereoselective cascade [5 + 1] double Michael reaction, a route for the synthesis of spiro(thio)oxindoles.

The first diastereoselective synthesis of spirothiooxindoles is reported via the Michael reaction between thiooxindoles and dibenzalacetones. The reaction was conducted without any catalyst or additive under green conditions, i.e., ethanol as the solvent and at room temperature. In addition, the described robust method benefits from scalability, simple work-up, and column chromatography-free purification. This work demonstrates the art of governing regio- and stereoselectivity, which has been discussed in the light of Density Functional Theory calculations. Our method represents the first synthesis of spiro[cyclohexanone-thiooxindoles] with the relative configuration of the aryl moieties at the cyclohexanone ring as cis. The obtained cis-spirothiooxindoles, can be used to afford cis-spirooxindoles, which their synthesis had not been explored before. According to our molecular docking studies, cis-spirooxindoles demonstrate higher binding affinities than corresponding trans-spirooxindoles for the OPRT domain of the Leishmania donovani uridine 5'-monophosphate synthase (LdUMPS). Thus, the reported method may eventually be utilized to develop new hit compounds for leishmaniasis treatment.

A Multidisciplinary Focus Review of Musculoskeletal Disorders Among Operating Room Personnel.

Musculoskeletal disorder is one of the major health issues and is recognized as the second most common occupational disease. The aim of the present study was to investigate the different aspects of musculoskeletal disorders in operating room personnel. The present study was conducted to evaluate the prevalence of MSDs among operating room personnel, in January 2020. In this study, the authors explored 30 articles from five databases including Medline/PubMed, ProQuest, Scopus, Embase, and Google Scholar. The present study found that physical, psychological, and demographic characteristics including age, gender, work experience, and smoking were the most important risk factors for these disorders. Musculoskeletal disorders were also prevalent in different areas of the body, with the highest prevalence being in the lumbar region. In addition, regular exercise and physical activity, the use of stretching and gentle exercise to reduce physical pressure, regard to the principles of ergonomics in the workplace, regular physical examinations, and awareness of the risk factors for these disorders. Therefore, operating room officials need to promote operating room programs focused on reducing musculoskeletal disorders and increase the awareness of the personnel about the risk factors by conducting training courses.

Cerebral hemodynamic abnormalities of patients with ischemic stroke who are opium addicted: A study by transcranial doppler ultrasonography.

Background: Ischemic stroke as the major cause of mortality and morbidity worldwide has different risk factors. One of its modifiable risk factors is opium addiction whose role is not clear yet. This study aimed at assessing the hemodynamic parameters in ischemic stroke patients addicted to opium using transcranial Doppler (TCD) ultrasonography and comparing them with non-addicted patients. Methods: This comparative cross-sectional study was conducted in an academic hospital in the north of Iran in 2016. All the patients diagnosed as ischemic stroke underwent cerebrovascular ultrasound in the first 4 days of symptoms onset. Frequency of hemodynamic abnormalities confirmed by pulsatility index (PI) and mean flow velocity (MFV) were determined and compared between the two groups. The data were analyzed by chi-square test, t-test, and multiple logistic regression models using SPSS software. Results: A total of 353 patients with ischemic stroke (92 addicted and 261 non-addicted patients) were enrolled in the study. Univariate analysis indicated that the PI and MFV differences were statistically significant between two groups of addicted and non-addicted patients (P = 0.0001). By multivariate logistic regression model, the age [odds ratio (OR) = 1.143], diabetes mellitus (DM) (OR = 3.875), hypertension (HTN) (OR = 2.557), and opium usage (OR = 9.615) had influence on PI and only opium usage (OR = 3.246) had influence on MFV. Conclusion: Opium usage affects the cerebral hemodynamic parameters and increases the chance of having abnormal PI as ten-fold and abnormal MFV as three-fold.

Concerted dynamics of metallo-base pairs in an A/B-form helical transition.

Metal-mediated base pairs expand the repertoire of nucleic acid structures and dynamics. Here we report solution structures and dynamics of duplex DNA containing two all-natural C-HgII-T metallo base pairs separated by six canonical base pairs. NMR experiments reveal a 3:1 ratio of well-resolved structures in dynamic equilibrium. The major species contains two (N3)T-HgII-(N3)C base pairs in a predominantly B-form helix. The minor species contains (N3)T-HgII-(N4)C base pairs and greater A-form characteristics. Ten-fold different 1J coupling constants (15N,199Hg) are observed for (N3)C-HgII (114 Hz) versus (N4)C-HgII (1052 Hz) connectivities, reflecting differences in cytosine ionization and metal-bonding strengths. Dynamic interconversion between the two types of C-HgII-T base pairs are coupled to a global conformational exchange between the helices. These observations inspired the design of a repetitive DNA sequence capable of undergoing a global B-to-A-form helical transition upon adding HgII, demonstrating that C-HgII-T has unique switching potential in DNA-based materials and devices.