bluuebunny/crossref_metadata_2025 huggingface dataset:
Training‐induced acceleration of O2 uptake on‐kinetics precedes muscle mitochondrial biogenesis in humans
Authors: Zoladz Jerzy A. , Grassi Bruno , Majerczak Joanna , Szkutnik Zbigniew , Korostyński Michał , Karasiński Janusz , Kilarski Wincenty , Korzeniewski Bernard
Published: December 2012

New Findings

What is the central question of this study?

A few weeks of endurance training accelerate the oxygen uptake () on‐kinetics in humans. The main aim of the present study was to determine whether the acceleration of on‐kinetics obtained by a short period of moderate‐intensity training can be explained by an intensification of mitochondrial biogenesis.

What is the main finding and its importance?

We demonstrated that 5 weeks of moderate‐intensity training accelerates the on‐kinetics during moderate‐intensity cycling in the absence of enhanced mitochondrial biogenesis or capillarization in the trained muscles. We postulate that in the early stages of training an intensification of ‘parallel activation’ of oxidative phosphorylation could account for the shortening of the on‐transient.

The effects of 5 weeks of moderate‐intensity endurance training on pulmonary oxygen uptake kinetics ( on‐kinetics) were studied in 15 healthy men (mean ± SD: age 22.7 ± 1.8 years, body weight 76.4 ± 8.9 kg and maximal 46.0 ± 3.7 ml kg−1 min−1). Training caused a significant acceleration (P= 0.003) of on‐kinetics during moderate‐intensity cycling (time constant of the ‘primary’ component 30.0 ± 6.6 versus 22.8 ± 5.6 s before and after training, respectively) and a significant decrease (P= 0.04) in the amplitude of the primary component (837 ± 351 versus 801 ± 330 ml min−1). No changes in myosin heavy chain distribution, muscle fibre capillarization, level of peroxisome proliferator‐activated receptor γ coactivator 1α and other markers of mitochondrial biogenesis (mitochondrial DNA copy number, cytochrome c and cytochrome oxidase subunit I contents) in the vastus lateralis were found after training. A significant downregulation in the content of the sarcoplasmic reticulum ATPase 2 (SERCA2; P= 0.03) and a tendency towards a decrease in SERCA1 (P= 0.055) was found after training. The decrease in SERCA1 was positively correlated (P= 0.05) with the training‐induced decrease in the gain of the on‐kinetics ( at steady state/Δpower output). In the early stage of training, the acceleration in on‐kinetics during moderate‐intensity cycling can occur without enhanced mitochondrial biogenesis or changes in muscle myosin heavy chain distribution and in muscle fibre capillarization. The training‐induced decrease of the O2 cost of cycling could be caused by the downregulation of SERCA pumps.
Functional Characterization of Reductive Dehalogenases by Using Blue Native Polyacrylamide Gel Electrophoresis
Authors: Tang Shuiquan , Chan Winnie W. M. , Fletcher Kelly E. , Seifert Jana , Liang Xiaoming , Löffler Frank E. , Edwards Elizabeth A. , Adrian Lorenz
Published: December 2012

Dehalococcoides mccartyi
strains are obligate organohalide-respiring bacteria harboring multiple distinct reductive dehalogenase (RDase) genes within their genomes. A major challenge is to identify substrates for the enzymes encoded by these RDase genes. We demonstrate an approach that involves blue native polyacrylamide gel electrophoresis (BN-PAGE) followed by enzyme activity assays with gel slices and subsequent identification of proteins in gel slices using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). RDase expression was investigated in cultures of
Dehalococcoides mccartyi
strain BAV1 and in the KB-1 consortium growing on chlorinated ethenes and 1,2-dichloroethane. In cultures of strain BAV1, BvcA was the only RDase detected, revealing that this enzyme catalyzes the dechlorination not only of vinyl chloride, but also of all dichloroethene isomers and 1,2-dichloroethane. In cultures of consortium KB-1, five distinct
Dehalococcoides
RDases and one
Geobacter
RDase were expressed under the conditions tested. Three of the five RDases included orthologs to the previously identified chlorinated ethene-dechlorinating enzymes VcrA, BvcA, and TceA. This study revealed substrate promiscuity for these three enzymes and provides a path forward to further explore the largely unknown RDase protein family.
Uptake of α-Ketoglutarate by Citrate Transporter CitP Drives Transamination in Lactococcus lactis
Authors: Pudlik Agata M. , Lolkema Juke S.
Published: December 2012

Transamination is the first step in the conversion of amino acids into aroma compounds by lactic acid bacteria (LAB) used in food fermentations. The process is limited by the availability of α-ketoglutarate, which is the best α-keto donor for transaminases in LAB. Here, uptake of α-ketoglutarate by the citrate transporter CitP is reported. Cells of
Lactococcus lactis
IL1403 expressing CitP showed significant levels of transamination activity in the presence of α-ketoglutarate and one of the amino acids Ile, Leu, Val, Phe, or Met, while the same cells lacking CitP showed transamination activity only after permeabilization of the cell membrane. Moreover, the transamination activity of the cells followed the levels of CitP in a controlled expression system. The involvement of CitP in the uptake of the α-keto donor was further demonstrated by the increased consumption rate in the presence of
l
-lactate, which drives CitP in the fast exchange mode of transport. Transamination is the only active pathway for the conversion of α-ketoglutarate in IL1403; a stoichiometric conversion to glutamate and the corresponding α-keto acid from the amino acids was observed. The transamination activity by both the cells and the cytoplasmic fraction showed a remarkably flat pH profile over the range from pH 5 to pH 8, especially with the branched-chain amino acids. Further metabolism of the produced α-keto acids into α-hydroxy acids and other flavor compounds required the coupling of transamination to glycolysis. The results suggest a much broader role of the citrate transporter CitP in LAB than citrate uptake in the citrate fermentation pathway alone.
Evidence for Phenotypic Plasticity among Multihost Campylobacter jejuni and C. coli Lineages, Obtained Using Ribosomal Multilocus Sequence Typing and Raman Spectroscopy
Authors: Read Daniel S. , Woodcock Dan J. , Strachan Norval J. C. , Forbes Kenneth J. , Colles Frances M. , Maiden Martin C. J. , Clifton-Hadley Felicity , Ridley Anne , Vidal Ana , Rodgers John , Whiteley Andrew S. , Sheppard Samuel K.
Published: December 2012

Closely related bacterial isolates can display divergent phenotypes. This can limit the usefulness of phylogenetic studies for understanding bacterial ecology and evolution. Here, we compare phenotyping based on Raman spectrometric analysis of cellular composition to phylogenetic classification by ribosomal multilocus sequence typing (rMLST) in 108 isolates of the zoonotic pathogens
Campylobacter jejuni
and
C. coli
. Automatic relevance determination (ARD) was used to identify informative peaks in the Raman spectra that could be used to distinguish strains in taxonomic and host source groups (species, clade, clonal complex, and isolate source/host). Phenotypic characterization based on Raman spectra showed a degree of agreement with genotypic classification using rMLST, with segregation accuracy between species (83.95%), clade (in
C. coli
, 98.41%), and, to some extent, clonal complex (86.89%
C. jejuni
ST-21 and ST-45 complexes) being achieved. This confirmed the utility of Raman spectroscopy for lineage classification and the correlation between genotypic and phenotypic classification. In parallel analysis, relatively distantly related isolates (different clonal complexes) were assigned the correct host origin irrespective of the clonal origin (74.07 to 96.97% accuracy) based upon different Raman peaks. This suggests that the phenotypic characteristics, from which the phenotypic signal is derived, are not fixed by clonal descent but are influenced by the host environment and change as strains move between hosts.
A Combined System for Engineering Glycosylation Efficiency and Glycan Structure in Saccharomyces cerevisiae
Authors: Parsaie Nasab Farnoush , Aebi Markus , Bernhard Gesche , Frey Alexander Daniel
Published: December 2012

We describe a novel synthetic N-glycosylation pathway to produce recombinant proteins carrying human-like N-glycans in
Saccharomyces cerevisiae
, at the same time addressing glycoform and glycosylation efficiency. The Δ
alg3
Δ
alg11
double mutant strain, in which the N-glycans are not matured to their native high-mannose structure, was used. In this mutant strain, lipid-linked Man
3
GlcNAc
2
is built up on the cytoplasmic side of the endoplasmic reticulum, flipped by an artificial flippase into the ER lumen, and then transferred with high efficiency to the nascent polypeptide by a protozoan oligosaccharyltransferase. Protein-bound Man
3
GlcNAc
2
serves directly as a substrate for Golgi apparatus-targeted human N-acetylglucosaminyltransferases I and II. Our results confirmed the presence of the complex human-like N-glycan structure GlcNAc
2
Man
3
GlcNAc
2
on the secreted monoclonal antibody HyHEL-10. However, due to the interference of Golgi apparatus-localized mannosyltransferases, heterogeneity of N-linked glycans was observed.
A Genetic System for Clostridium ljungdahlii: a Chassis for Autotrophic Production of Biocommodities and a Model Homoacetogen
Authors: Leang Ching , Ueki Toshiyuki , Nevin Kelly P. , Lovley Derek R.
Published: December 2012

Methods for genetic manipulation of
Clostridium ljungdahlii
are of interest because of the potential for production of fuels and other biocommodities from carbon dioxide via microbial electrosynthesis or more traditional modes of autotrophy with hydrogen or carbon monoxide as the electron donor. Furthermore, acetogenesis plays an important role in the global carbon cycle. Gene deletion strategies required for physiological studies of
C. ljungdahlii
have not previously been demonstrated. An electroporation procedure for introducing plasmids was optimized, and four different replicative origins for plasmid propagation in
C. ljungdahlii
were identified. Chromosomal gene deletion via double-crossover homologous recombination with a suicide vector was demonstrated initially with deletion of the gene for FliA, a putative sigma factor involved in flagellar biogenesis and motility in
C. ljungdahlii
. Deletion of
fliA
yielded a strain that lacked flagella and was not motile. To evaluate the potential utility of gene deletions for functional genomic studies and to redirect carbon and electron flow, the genes for the putative bifunctional aldehyde/alcohol dehydrogenases,
adhE1
and
adhE2
, were deleted individually or together. Deletion of
adhE1
, but not
adhE2
, diminished ethanol production with a corresponding carbon recovery in acetate. The double deletion mutant had a phenotype similar to that of the
adhE1
-deficient strain. Expression of
adhE1
in
trans
partially restored the capacity for ethanol production. These results demonstrate the feasibility of genetic investigations of acetogen physiology and the potential for genetic manipulation of
C. ljungdahlii
to optimize autotrophic biocommodity production.
Autofluorescence as a Tool for Structural Analysis of Biofilms Formed by Nonpigmented Rapidly Growing Mycobacteria
Authors: Muñoz-Egea María-Carmen , García-Pedrazuela María , Mahillo Ignacio , García María Jesús , Esteban Jaime
Published: December 2012

The structure of biofilms formed by seven nonpigmented rapidly growing mycobacteria, including saprophytes and opportunistic species, was analyzed. Analysis included amount of covered surface, thickness, cell viability, and presence of intrinsic autofluorescence at different times using confocal laser scanning microscopy and image analysis. Autofluorescence was detected inside and outside cells of all mycobacteria.
Escherichia coli and Klebsiella pneumoniae Producing CTX-M Cephalosporinase from Swine Finishing Barns and Their Association with Antimicrobial Use
Authors: Mollenkopf Dixie F. , Mirecki Jennifer M. , Daniels Joshua B. , Funk Julie A. , Henry Steven C. , Hansen Glenn E. , Davies Peter R. , Donovan Tara S. , Wittum Thomas E.
Published: December 2012

We report the recovery of
Escherichia coli
or
Klebsiella pneumoniae
containing the extended-spectrum β-lactamase gene
bla
CTX-M
from 24 of 1,495 (1.6%) swine fecal samples in 8 of 50 (16%) finishing barns located in 5 U.S. states. We did not detect an association between antimicrobial use and recovery of
bla
CTX-M
.
Aeromonas and Pseudomonas Species Carriers of
ampC
FOX Genes in Aquatic Environments
Authors: Voolaid Veiko , Tenson Tanel , Kisand Veljo
Published: December 2012

Resistance to beta-lactam antibiotics is evolutionarily ancient, and resistance to new drugs develops and quickly spreads. Most studies on beta-lactam resistance concentrate on pathogens in medical and veterinary settings. We show that
ampC
FOX genes can be found in natural environmental isolates.
The Type III Secretion System of Bradyrhizobium japonicum USDA122 Mediates Symbiotic Incompatibility with
Rj2
Soybean Plants
Authors: Tsukui Takahiro , Eda Shima , Kaneko Takakazu , Sato Shusei , Okazaki Shin , Kakizaki-Chiba Kaori , Itakura Manabu , Mitsui Hisayuki , Yamashita Akifumi , Terasawa Kimihiro , Minamisawa Kiwamu
Published: December 2012

The
rhcJ
and
ttsI
mutants of
Bradyrhizobium japonicum
USDA122 for the type III protein secretion system (T3SS) failed to secrete typical effector proteins and gained the ability to nodulate
Rj2
soybean plants (Hardee), which are symbiotically incompatible with wild-type USDA122. This suggests that effectors secreted via the T3SS trigger incompatibility between these two partners.
Activation of an Essential Calcium Signaling Pathway in Saccharomyces cerevisiae by Kch1 and Kch2, Putative Low-Affinity Potassium Transporters
Authors: Stefan Christopher P. , Zhang Nannan , Sokabe Takaaki , Rivetta Alberto , Slayman Clifford L. , Montell Craig , Cunningham Kyle W.
Published: December 2012

In the budding yeast
Saccharomyces cerevisiae
, mating pheromones activate a high-affinity Ca
2+
influx system (HACS) that activates calcineurin and is essential for cell survival. Here we identify extracellular K
+
and a homologous pair of transmembrane proteins, Kch1 and Kch2 (Prm6), as necessary components of the HACS activation mechanism. Expression of Kch1 and especially Kch2 was strongly induced during the response to mating pheromones. When forcibly overexpressed, Kch1 and Kch2 localized to the plasma membrane and activated HACS in a fashion that depended on extracellular K
+
but not pheromones. They also promoted growth of
trk1 trk2
mutant cells in low K
+
environments, suggesting they promote K
+
uptake. Voltage-clamp recordings of protoplasts revealed diminished inward K
+
currents in
kch1 kch2
double-mutant cells relative to the wild type. Conversely, heterologous expression of Kch1 in HEK293T cells caused the appearance of inwardly rectifying K
+
currents. Collectively, these findings suggest that Kch1 and Kch2 directly promote K
+
influx and that HACS may electrochemically respond to K
+
influx in much the same way as the homologous voltage-gated Ca
2+
channels in most animal cell types.
Why do clinicians not refer patients to online decision support tools? Interviews with front line clinics in the NHS
Authors: Elwyn Glyn , Rix Andrew , Holt Tom , Jones Deborah
Published: December 2012

Objective

To assess whether clinical teams would direct patients to use web-based patient decision support interventions (DESIs) and whether patients would use them.

Design

Retrospective semistructured interviews and web server log analysis.

Participants and settings

57 NHS professionals (nurses, doctors and others) in orthopaedic, antenatal, breast, urology clinics and in primary care practices across 22 NHS sites given access to DESIs hosted on the NHS Direct website.

Results

Fewer than expected patients were directed to use the web tools. The most significant obstacles to referral to the tools were the attitudes of clinicians and clinical teams. Technical problems contributed to the problems but the low uptake was mainly explained by clinicians’ limited understanding of how patient DESIs could be helpful in clinical pathways, their perception that ‘shared decision-making’ was already commonplace and that, in their view, some patients are resistant to being involved in treatment decisions. External factors, such as efficiency targets and ‘best practice’ recommendations were also cited being significant barriers. Clinicians did not feel the need to refer patients to use decision support tools, web-based or not, and, as a result, felt no requirement to change existing practice routines. Uptake is highest when clinicians set expectations that these tools are integral to practice and embed their use into clinical pathways.

Conclusions

Existing evidence of patient benefit and the free availability of patient DESIs via the web are not sufficient drivers to achieve routine use. Health professionals were not motivated to refer patients to these interventions. Clinicians will not use these interventions simply because they are made available, despite good evidence of benefit to patients. These attitudes are deep seated and will not be modified by solely developing web-based interventions: a broader strategy will be required to embed DESIs into routine practice.
Clinical features of myocardial infarction and myocarditis in young adults: a retrospective study
Authors: Pellaton Cyril , Monney Pierre , Ludman Andrew James , Schwitter Juerg , Eeckhout Eric , Hugli Olivier , Muller Olivier
Published: December 2012

Objectives

To evaluate the prevalence and clinical presentation of myocardial infarction (MI) and myocarditis in young adults presenting with chest pain (CP) and an elevated serum troponin I (TnI) to the emergency department (ED).

Design

Retrospective, observational, single-centre study.

Participants

All consecutive patients 18–40 years old admitted to the ED for CP with an elevated TnI concentration.

Primary outcome measures

Prevalence of MI, myocarditis and the characterisation of clinical presentation.

Results

1588 patients between 18 and 40 years old were admitted to the ED with CP during 30 consecutive months. 49 (3.1%) patients with an elevated TnI (>0.09 μg/l) were included. 32.7% (16/49) were diagnosed with MI (11 ST-elevation myocardial infarction (STEMI) and 5 non-ST-elevation myocardial infarction (NSTEMI)) and 59.2% (29/49) with myocarditis. Compared with patients with myocarditis, MI patients were older (34.1±3.8 vs 26.9±6.4, p=0.0002) with more cardiovascular risk factors (mean 2.06 vs 0.69). Diabetes (18.8% vs 0%, p=0.0039), dyslipidaemia (56.2% vs 3.4%, p<0.0001) and family history of coronary artery disease (CAD) (37.5% vs 10.3% p=0.050) were associated with MI. Fever or recent viral illness were present in 75.9% (22/29) of patients with myocarditis, and in 0% of MI patients (p<0.0001). During follow-up, two patients with myocarditis were re-admitted for CP.

Conclusions

In this study, 32.7% of patients <40-year-old admitted to an ED with CP and elevated TnI had a diagnosis of MI. Key distinctive clinical factors include diabetes, dyslipidaemia, family history of CAD and fever or recent viral illness.
Predictors of cardiovascular events in a contemporary population with impaired glucose tolerance: an observational analysis of the Nateglinide and Valsartan in impaired glucose tolerance outcomes research (NAVIGATOR) trial
Authors: Preiss David , Thomas Laine E , Sun Jie-Lena , Haffner Steven M , Holman Rury R , Standl Eberhard , Leiter Lawrence A , Mazzone Theodore , Rutten Guy E , Tognoni Gianni , Martinez Felipe A , Chiang Fu-Tien , Califf Robert M , McMurray John J
Published: December 2012

Objectives

Risk factors for cardiovascular events are well established in general populations and those with diabetes but have been sparsely studied in impaired glucose tolerance (IGT). We sought to identify predictors of (1) a composite cardiovascular outcome (cardiovascular death, non-fatal myocardial infarction and non-fatal stroke) and (2) cardiovascular death, among patients with IGT.

Design

We studied participants enrolled in the Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes Research (NAVIGATOR) trial. Predictors of cardiovascular events were identified in observational analyses.

Setting

Clinical trial participants in 40 countries.

Participants

9306 participants with biochemically confirmed IGT at high risk of cardiovascular events participated in NAVIGATOR.

Primary and secondary outcome measures

Cox proportional hazard regression models were constructed using variables (demographic data, medical history, clinical features, biochemical results and ECG findings) recorded at baseline to identify variables associated with and predictive of cardiovascular events.

Results

Over 6.4 years, 639 (6.9%) participants experienced a cardiovascular event, and 244 (2.6%) cardiovascular death. While predictors of both outcomes included established risk factors such as existing cardiovascular disease, male gender, older age, current smoking status and higher low-density lipoprotein cholesterol, other variables such as reduced estimated glomerular filtration rate, previous thromboembolic disease, atrial fibrillation, higher urinary albumin/creatinine ratio and chronic obstructive pulmonary disease were also important predictors. Glycaemic measures were not predictive of cardiovascular events. c-Statistics for predicting cardiovascular events and cardiovascular death were 0.74 and 0.82, respectively. This compares with c-statistics for cardiovascular events and cardiovascular death of 0.65 and 0.71, respectively, using the classical Framingham risk factors of age, total cholesterol, high-density lipoprotein cholesterol, systolic blood pressure, treatment for hypertension and smoking status.

Conclusions

The most powerful independent predictors of cardiovascular events in IGT included both established risk factors and other variables excluding measures of glycaemia, allowing effective identification of high-risk individuals.
Instruments used to measure the effectiveness of palliative care education initiatives at the undergraduate level: a critical literature review
Authors: Frey Rosemary Ann , Gott Merryn , Neil Hayley
Published: December 2012

Background

The increase in the numbers of patients with palliative care needs has resulted in growing pressures on the small number of specialist palliative care providers within the New Zealand context. These pressures can potentially be eased by ensuring an adequately trained workforce, beginning with undergraduate training in the healthcare field. The goal of the present review is to ascertain what tools exist to measure the effectiveness of undergraduate palliative care education initiatives.

Method

A systematic review of qualitative and quantitative literature was undertaken. Searches within ERIC, CINAHL Plus, Medline and Medline in Progress, and Google Scholar databases were conducted for the period 1990–2011. A checklist adapted from Hawkeret alwas used to select and assess data.

Results

14 of the 112 articles met the inclusion criteria. Overall inconsistencies in the amount of validation information provided and a narrow focus on aspects of palliative care competence was apparent. No universally applicable validated questionnaire to assess the effectiveness of undergraduate palliative care education could be identified.

Conclusions

The increased focus by educational institutions on instilling palliative care skills in healthcare students necessitates the development of comprehensive and validated tools to evaluate the effectiveness of education initiatives.
The lived experience of physicians dealing with patient death
Authors: Whitehead Paul Richard
Published: December 2012

Background

A growing body of research indicates that physicians suffer high levels of stress, depression and burnout. Related literature has found that physician stress can negatively impact patient care. This study builds upon previous research that found some dying patients experienced ‘iatrogenic suffering’ caused by the way physicians communicated with them regarding terminal diagnoses and palliative treatment. The goal of this research was to explore physicians’ experiences of dealing with patient death in order to understand how such experiences affect them and their communication with patients.

Methods

This study used qualitative methods to conduct and analyse 10 individual, semistructured interviews with senior physicians from several specialty areas at a large, tertiary care hospital. The resulting themes were validated using member checks and expert review.

Results

This article presents five essential themes that provide a concise description of the lived experience of patient death for these physicians. Interpretation: These themes indicate that physicians can experience very strong and lasting emotional reactions to some patient deaths, and also that patient death can elicit intense experiences related to professional responsibility and competence. A key finding is the description of a complex process of managing the balance between personal and professional reactions in the face of patient death. The implication is that difficulties negotiating this balance may lead to unintended lapses in compassion and suboptimal outcomes in patient care.
Whole slide images for primary diagnostics of paediatric pathology specimens: a feasibility study
Authors: Al-Janabi Shaimaa , Huisman André , Nikkels Peter G J , ten Kate Fiebo J W , van Diest Paul J
Published: December 2012

Introduction

Whole slide images (WSI) have been used in many pathology applications such as teleconsultation, teaching and research, but not in primary diagnostics. The aim of this study was to test the feasibility of using WSI in primary diagnostics of paediatric pathology specimens and placental tissue.

Materials and methods

Eighty consecutive tissues biopsies and resections from patients under 18 years old were selected, as well as 20 placentas. These cases had been diagnosed in the year 2009 by a single pathologist. The same pathologist who had performed the original diagnosis based on light microscopy was asked to rediagnose these 100 cases on WSI scanned at 20× magnification as well as by light microscopy having the original clinical information available, but blinded to the original light microscopic diagnoses. The original diagnoses were compared with WSI based diagnoses and rediagnoses by light microscopy and classified as concordant, mildly discordant (without clinical consequences) and discordant (with clinical consequences).

Results

The original diagnoses were concordant with WSI and light microscopic diagnoses in 90% and 93% of cases respectively, which was not significantly different. Digital reassessment yielded eight mild discrepancies and two discrepant cases (2%) where the difference in diagnoses could have clinical implications for the patient. Light microscopic reassessment showed seven mild discrepancies. It turned out to be difficult to identify nucleated red blood cells on WSI, even when scanned at 40×.

Conclusions

Primary diagnostics of paediatric tissue biopsies and resections can generally well be done on WSI. However, some difficulties were encountered in examining placenta tissue where the identification of nucleated red blood cells may need higher resolution or even scanning at multiple focus depths, which is well possible on most current slide scanners.
Synthesis of hydrazine and azapeptide derivatives by alkylation of carbazates and semicarbazones
Authors: Garcia-Ramos Yesica , Proulx Caroline , Lubell William D.
Published: December 2012

Hydrazine and azapeptide analogs were synthesized effectively by alkylation of alkylidene carbazates and semicarbazones. In comparisons of benzylidene, benzhydrylidene, and fluorenylidene tert-butyl carbazates in alkylations using bases of different pKb character, superior conversion was obtained using the fluorenone derivative. Mild alkylation conditions were found employing Et4NOH as base and used to convert fluorenylidene tert-butyl carbazate into 13 different protected hydrazines. Moreover, racemization was avoided during alkylation of fluorenylidene semicarbazide in the synthesis of aza-propargylglycinylphenylalanine tert-butyl ester, the protecting groups from which could be selectively removed.
Ultrasound-mediated targeted drug delivery: recent success and remaining challenges
Authors: Castle Jason , Butts Matthew , Healey Andrew , Kent Kevin , Marino Michael , Feinstein Steven B.
Published: December 2012

The potential clinical value of developing a novel, nonviral, ultrasound-directed gene and drug delivery system is immense. Investigators soon will initiate clinical trials with the goal of treating a wide variety of maladies using noninvasive, ultrasound-based technology. The ongoing, scientific validation associated with promising preclinical success portents a novel range of therapeutics. The clinical utility and eventual clinical successes await vigorous testing. This review highlights the recent successes and challenges within the field of ultrasound-mediated drug delivery.
Different roles of the cardiac Na+/Ca2+-exchanger in ouabain-induced inotropy, cell signaling, and hypertrophy
Authors: Bai Yan , Morgan Eric E. , Giovannucci David R. , Pierre Sandrine V. , Philipson Kenneth D. , Askari Amir , Liu Lijun
Published: December 2012

Previous studies have shown that digitalis drugs, acting as specific inhibitors of cardiac Na+/K+-ATPase, not only cause positive inotropic effects, but also activate cell signaling pathways that lead to cardiac myocyte hypertrophy. A major aim of this work was to assess the role of Na+/Ca2+-exchanger, NCX1, in the above two seemingly related drug effects. Using a mouse with ventricular-specific knockout (KO) of NCX1, ouabain-induced positive inotropy that was evident in isolated wild-type (Wt) hearts was clearly reduced in KO hearts. Ouabain also increased Ca2+transient amplitudes in Wt myocytes, but not in KO myocytes. Ouabain-induced activations of ERK 1/2 were noted in Wt myocytes, but not in KO myocytes; however, ouabain activated PI3K1A and Akt in both Wt and KO myocytes. Protein synthesis rate, as a measure of hypertrophy, was increased by ouabain in Wt and KO myocytes; these drug effects were prevented by a PI3K inhibitor but not by a MEK/ERK inhibitor. Hypertrophy caused by ET-1, but not that induced by ouabain, was accompanied by upregulation of BNP gene in Wt and KO myocytes. The findings indicate 1) the necessity of NCX1 for positive inotropic action of ouabain; 2) the irrelevance of NCX1 and ERK 1/2 activation to ouabain-induced hypertrophy; and 3) that hypertrophy caused by ouabain through the activation of PI3K1A/Akt pathway is likely to be beneficial to the heart.
Nampt secreted from cardiomyocytes promotes development of cardiac hypertrophy and adverse ventricular remodeling
Authors: Pillai Vinodkumar B. , Sundaresan Nagalingam R. , Kim Gene , Samant Sadhana , Moreno-Vinasco Liliana , Garcia Joe G. N. , Gupta Mahesh P.
Published: December 2012

Nicotinamide phosphoribosyltransferase (Nampt) is an important coenzyme involved in cellular redox reactions. Inside the cell, Nampt (iNampt) functions as a rate-limiting enzyme in the NAD salvage pathway, and outside the cell (eNampt), it acts as a proinflammatory cytokine. High-circulating levels of Nampt are reported in different pathological conditions. This study was designed to examine the role of Nampt in the development of cardiac hypertrophy and ventricular remodeling. We studied the hypertrophic response in Nampt heterozygous (+/−) knockout and cardiac-specific overexpressing Nampt transgenic mice. Whereas Nampt+/−mice were protected against agonist (isoproterenol and angiotensin II)-induced hypertrophy, Nampt transgenic mice spontaneously developed cardiac hypertrophy at 6 mo of age. Experiments conducted to gain insight into the mechanism revealed that treatment of cardiomyocytes with recombinant (eNampt) or overexpression with Nampt-synthesizing adenovirus vector (Ad.Nampt) induced cardiomyocyte hypertrophy. The prohypertrophic effects of eNampt and Ad.Nampt were blocked by the addition of a Nampt-blocking antibody into cultures, thus suggesting that Nampt was in fact invoking hypertrophic response of cardiomyocytes by acting on the cell surface receptors. We also found increased Nampt levels in the supernatant of cardiomyocyte cultures subjected to stress by either serum starvation or H2O2treatment. Exploration of signaling pathways in Nampt-induced cardiac hypertrophy and fibrosis revealed increased activation of mitogen-activated protein kinases, namely, JNK1, p38, and ERK. This was also associated with increased calcineurin levels and nuclear factor of activated T-cell localization into the nucleus. From these studies we conclude that cardiomyocytes are capable of secreting Nampt during stress, and exogenous Nampt is a positive regulator of cardiac hypertrophy and adverse ventricular remodeling.
A computational model of hemorrhage and dehydration suggests a pathophysiological mechanism: Starling-mediated protein trapping
Authors: Reisner Andrew T. , Heldt Thomas
Published: December 2012

We sought to understand the degree to which a single computational cardiovascular model could replicate the typical responses of healthy subjects through a breadth of blood loss patterns and whether such a model could illuminate the cause-effect relationships that underlie the observed responses. The model consisted of compartments for the upper body, lower body, viscera, and kidneys as well as a four-chambered heart and a pulmonary compartment. Transcapillary fluid flux was governed by Starling forces, whereas lymphatic flow was driven by hydrostatic tissue pressure and scaled by a lymphatic activation term. We adjusted parameters based on results from one protocol involving moderate continual blood loss in a canine model. Next, we simulated six additional protocols spanning euvolemic and dehydrated subjects and compared in silico behavior with in vivo hemodynamic responses and fluid shifts. The model was able to replicate group-averaged behavior (i.e., within 1 or 2 SEs) of the rate and quantity of vascular refill and the associated cardiac output during slow, moderate, and rapid ongoing blood losses, the restitution after the cessation of blood loss, and the absence of restitution in dehydrated subjects. The model suggested that the earlier phase of restitution, i.e., transcapillary fluid shifts, was antagonistic to the later phase of restitution, i.e., protein return via lymphatics. This phenomenon was termed “interstitial protein trapping.” In conclusion, the model appears valid for a range of blood loss patterns and prehydration states. Further investigation into the in vivo relevance of interstitial protein trapping is justified.
Myocardial oxidative metabolism and protein synthesis during mechanical circulatory support by extracorporeal membrane oxygenation
Authors: Priddy Colleen M. O′Kelly , Kajimoto Masaki , Ledee Dolena R. , Bouchard Bertrand , Isern Nancy , Olson Aaron K. , Rosiers Christine Des , Portman Michael A.
Published: December 2012

Extracorporeal membrane oxygenation (ECMO) provides essential mechanical circulatory support necessary for survival in infants and children with acute cardiac decompensation. However, ECMO also causes metabolic disturbances, which contribute to total body wasting and protein loss. Cardiac stunning can also occur, which prevents ECMO weaning, and contributes to high mortality. The heart may specifically undergo metabolic impairments, which influence functional recovery. We tested the hypothesis that ECMO alters oxidative metabolism and protein synthesis. We focused on the amino acid leucine and integration with myocardial protein synthesis. We used a translational immature swine model in which we assessed in heart 1) the fractional contribution of leucine (FcLeucine) and pyruvate to mitochondrial acetyl-CoA formation by nuclear magnetic resonance and 2) global protein fractional synthesis (FSR) by gas chromatography-mass spectrometry. Immature mixed breed Yorkshire male piglets ( n = 22) were divided into four groups based on loading status (8 h of normal circulation or ECMO) and intracoronary infusion [13C6,15N]-L-leucine (3.7 mM) alone or with [2-13C]-pyruvate (7.4 mM). ECMO decreased pulse pressure and correspondingly lowered myocardial oxygen consumption (∼40%, n = 5), indicating decreased overall mitochondrial oxidative metabolism. However, FcLeucine was maintained and myocardial protein FSR was marginally increased. Pyruvate addition decreased tissue leucine enrichment, FcLeucine, and Fc for endogenous substrates as well as protein FSR. The heart under ECMO shows reduced oxidative metabolism of substrates, including amino acids, while maintaining 1) metabolic flexibility indicated by ability to respond to pyruvate and 2) a normal or increased capacity for global protein synthesis.
Sex differences in sympathetic neural and limb vascular reactivity to mental stress in humans
Authors: Yang Huan , Drummer Thomas D. , Carter Jason R.
Published: December 2012

Mental stress elicits a robust and consistent forearm vasodilation, but vascular reactivity in the calf remains inconsistent. It has been reported that calf vascular responses to MS may be sex dependent. Muscle sympathetic nerve activity (MSNA) is an important contributor to calf blood flow (CBF), yet the relations between sex, limb blood flow, and MSNA reactivity to mental stress have not been explored. We hypothesized that mental stress would elicit more dramatic vasodilation of the limbs in women and that this might be explained by reduced MSNA reactivity and/or blunted sympathetic vascular transduction. We measured heart rate (HR), mean arterial pressure (MAP), CBF, calf vascular conductance (CVC), forearm blood flow (FBF), forearm vascular conductance (FVC), and MSNA concurrently in 18 men (age: 23 ± 2 yr) and 16 women (age: 24 ± 2 yr) during 5 min of supine baseline and 5 min of mental stress. Mental stress elicited similar increases in MAP (Δ10 ± 1 vs. Δ11 ± 1 mmHg), HR (Δ16 ± 2 vs. Δ17 ± 2 beats/min), FBF (Δ81 ± 16% vs. Δ83 ± 15%), and FVC (Δ62 ± 13% vs. Δ65 ± 13%) in men and women, respectively. In contrast, CBF (Δ16 ± 8% vs. Δ37 ± 9%, P = 0.036) and CVC (Δ4 ± 7% vs. Δ24 ± 8%, P = 0.036) responses were exaggerated in women compared with men. Changes in FVC were significantly correlated with changes in CVC in women ( r = 0.681, P = 0.004) but not in men. MSNA reactivity to mental stress was not different between men and women; however, changes in CVC were negatively correlated with increases of MSNA in men ( r = −0.411, P = 0.045) but not in women. In conclusion, our data suggest different patterns of calf vascular reactivity to mental stress in men and women that might relate, in part, to altered vascular transduction of MSNA.
Endothelial 12(S)-HETE vasorelaxation is mediated by thromboxane receptor inhibition in mouse mesenteric arteries
Authors: Siangjong Lawan , Gauthier Kathryn M. , Pfister Sandra L. , Smyth Emer M. , Campbell William B.
Published: December 2012

Arachidonic acid (AA) metabolites mediate endothelium-dependent relaxation in many vascular beds. Previously, we identified the major AA 12/15-lipoxygenase (12/15-LO) metabolite of mouse arteries as 12-hydroxyeicosatetraenoic acid (12-HETE). The goal was to determine the stereospecific configuration of mouse vascular 12-HETE and characterize the role of 12-HETE stereoisomers in the regulation of vascular tone. Using normal, reverse phase, and chiral HPLC, the stereospecific configuration was identified as 12( S)-HETE. 12( S)-HETE relaxed U46619-, carbocyclic thromboxane A2-, PGF2α-, and 8-iso PGF2α-preconstricted mesenteric arteries, but not phenylephrine-preconstricted arteries. 12( R)-HETE was more potent than 12( S)-HETE in relaxing U46619-preconstricted mouse arteries (maximum relaxations = 91.4 ± 2.7% and 71.8 ± 5.9%, respectively). Neither 12-HETE isomer caused constriction. Pretreatment with 12( S)- or 12( R)-HETE (1 μM) inhibited constrictions to U46619 but not phenylephrine. To investigate the role of thromboxane A2(TP) receptors in 12-HETE vascular actions, [3H]SQ29548 radioligand binding studies were performed in mouse platelets. U46619, 12( R)-HETE, and 12( S)-HETE displaced [3H]SQ29548 binding with IC50s of 0.07, 0.32, and 1.73 μM, respectively. Both 12( S)- and 12( R)-HETE inhibited intracellular calcium increases induced by U46619 (10 nM) in HEK293 cells overexpressing TPαreceptor (65.5% and 45.1%, respectively) and coexpressing prostacyclin (IP) and TPαreceptors (58.0% and 27.1%, respectively). The LO inhibitor NDGA (10 μM) reduced AA relaxations in arteries preconstricted with U46619 but not phenylephrine. These results indicate that exogenous and endogenous 12( S)-HETE relax mouse mesenteric arteries that are preconstricted with thromboxane agonists. These 12( S)-HETE relaxations are mediated by TP receptor competitive inhibition and inhibition of TP agonist-induced increases in intracellular calcium.
Urine Metabolite Profiling of Human Colorectal Cancer by Capillary Electrophoresis Mass Spectrometry Based on MRB
Authors: Chen Jin-Lian , Fan Jing , Yan Liu-Shui , Guo Hui-Qin , Xiong Jing-Jing , Ren Yan , Hu Jun-Duo
Published: December 2012

Aim. The study was to investigate the metabolic profile of urine metabolites and to elucidate their clinical significance in patients with colorectal cancer.Methods. Colorectal cancers from early stage and advanced stage were used in this study. Urine samples of colorectal cancer patients and healthy adults were collected and subjected to capillary electrophoresis mass spectrometry based on moving reaction boundary analysis. The metabolic data were analyzed by SPSS 17.0 to find urinary biomarkers for colorectal cancer.Results. The results indicated that the urine metabolic profiling of colorectal cancer patients had significant changes compared with the normal controls, and there were also differences between early stage and advanced colorectal cancer patients. Compared with the control group, the levels of isoleucine, valine, arginine, lactate acid and leucine increased(P<0.05), but those of histidine, methionine, serine, aspartic acid, citric acid, succinate, and malic acid decreased in urine samples from colorectal cancer(P<0.05). Furthermore, the levels of isoleucine and valine were lower in urine of patients with advanced colorectal cancer than those in early stage colorectal cancer(P<0.05).Conclusion. The technique of capillary electrophoresis mass spectrometry based on MRB could reveal the significant metabolic alterations during progression of colorectal cancer, and the method is feasible and may be useful for the early diagnosis of colorectal cancer.
Percutaneous Soft Tissue Release for Treating Chronic Recurrent Myofascial Pain Associated with Lateral Epicondylitis: 6 Case Studies
Authors: Lin Ming-Ta , Chou Li-Wei , Chen Hsin-Shui , Kao Mu-Jung
Published: December 2012

Objective. The purpose of this pilot study is to investigate the effectiveness of the percutaneous soft tissue release for the treatment of recurrent myofascial pain in the forearm due to recurrent lateral epicondylitis.Methods. Six patients with chronic recurrent pain in the forearm with myofascial trigger points (MTrPs) due to chronic lateral epicondylitis were treated with percutaneous soft tissue release of Lin’s technique. Pain intensity (measured with a numerical pain rating scale), pressure pain threshold (measured with a pressure algometer), and grasping strength (measured with a hand dynamometer) were assessed before, immediately after, and 3 months and 12 months after the treatment.Results. For every individual case, the pain intensity was significantly reduced(P<0.01)and the pressure pain threshold and the grasping strength were significantly increased(P<0.01)immediately after the treatment. This significant effectiveness lasts for at least one year.Conclusions. It is suggested that percutaneous soft tissue release can be used for treating chronic recurrent lateral epicondylitis to avoid recurrence, if other treatment, such as oral anti-inflammatory medicine, physical therapy, or local steroid injection, cannot control the recurrent pain.
Changing Trends in the Prevalence and Disparities of Obesity and Other Cardiovascular Disease Risk Factors in Three Racial/Ethnic Groups of USA Adults
Authors: Romero Camila X. , Romero Tomas E. , Shlay Judith C. , Ogden Lorraine G. , Dabelea Dana
Published: December 2012

Objectives. To examine trends in the prevalence and disparities of traditional cardiovascular disease (CVD) risk factors among the major race/ethnic groups in the USA: non-Hispanic Whites (NHWs), non-Hispanic Blacks (NHBs), and Mexican Americans (MAs).Methods. We used cross-sectional trend analysis in women and men aged 25–84 years participating in the NHANES surveys, years 1988–1994 (n=14,341) and 1999–2004 (n=12,360).Results. The prevalence of obesity and hypertension increased significantly in NHW and NHB, both in men and women; NHB had the highest prevalence of obesity and hypertension in each time period. Diabetes prevalence showed a nonsignificant increasing trend in all groups and was higher in MA in both periods. Smoking significantly decreased in NHW men and NHB, the latter with the largest decline although the highest prevalence in each period; no changes were noted in MA, who had the lowest prevalence in both periods. Race/ethnic CVD risk factors disparities widened for obesity and hypercholesterolemia, remained unchanged for diabetes and hypertension, and narrowed for smoking.Conclusions. The increasing prevalence of obesity and hypertension underscores the need for better preventive measures, particularly in the NHB group that exhibits the worst trends. The decline in smoking rates may offset some of these unfavorable trends.
Use of i-scan Endoscopic Image Enhancement Technology in Clinical Practice to Assist in Diagnostic and Therapeutic Endoscopy: A Case Series and Review of the Literature
Authors: Hancock Shawn , Bowman Erik , Prabakaran Jyothiprashanth , Benson Mark , Agni Rashmi , Pfau Patrick , Reichelderfer Mark , Weiss Jennifer , Gopal Deepak
Published: December 2012

Background. i-scan is a software-driven technology that allows modifications of sharpness, hue, and contrast to enhance mucosal imaging. It uses postimage acquisition software with real-time mapping technology embedded in the endoscopic processor. Aims. To review applications of i-scan technology in clinical endoscopic practice. Methods. This is a case series of 20 consecutive patients who underwent endoscopic procedures where i-scan image enhancement algorithms were applied. The main outcome measures were to compare mucosal lesions with high-definition white light endoscopy (HD-WLE) and i-scan image enhancement for the application of diagnostic sampling and therapy. Results. 13 cases involving the upper GI tract and 7 cases of the lower GI tract are included. For upper GI tract pathology i-scan assisted in diagnosis or therapy of Barrett’s esophagus with dysplasia, esophageal adenocarcinoma, HSV esophagitis, gastric MALT lymphoma, gastric antral intestinal metaplasia with dysplasia, duodenal follicular lymphoma, and a flat duodenal adenoma. For lower GI tract pathology i-scan assisted in diagnosis or therapy of right-sided serrated adenomas, flat tubular adenoma, rectal adenocarcinoma, anal squamous cell cancer, solitary rectal ulcer, and radiation proctitis. Conclusions. i-scan imaging provides detailed topography of mucosal surfaces and delineates lesion edges, which can directly impact endoscopic management.