bluuebunny/crossref_metadata_2025_split huggingface dataset:
Response of urinary malondialdehyde to factors that stimulate lipid peroxidation in vivo
Authors: Dhanakoti S. N. , Draper H. H. 
Published: January 2007

AbstractMalondialdehyde (MDA) derivatives occur as normal constituents of rat and human urine. In a previous study, it was found that MDA excretion in rats is responsive to MDA intake and to certain factors that increase lipid peroxidation in vivo: vitamin E deficiency, iron administration and a high concentration of cod liver oil (CLO) fatty acids in the tissues. In the present study, the effect on MDA excretion of several additional dietary and endogeneous factors was evaluated.The composition of dietary fatty acids had a major influence on MDA excretion in fed animals, being highest for animals fed n−3 fatty acids (20∶5 and 22∶6) from CLO, intermediate for those fed n−6 (18∶2) acids from corn oil (CO) and lowest for those fed saturated acids from hydrogenated coconut oil (HCO). Diet was the main source of urinary MDA in all groups. Fasting produced a marked increase in urinary MDA, which tended to be higher in rats previously fed CLO. Fasting MDA excretion was not affected by the level of CO in the diet (5, 10 or 15%), indicating that feeding n−6 acids does not increase lipid peroxidation in vivo. Adrenocorticotropic hormone and epinephrine administration increased urinary MDA, further indicating that lipolysis either releases fatty acid peroxides from the tissues or increases the susceptibility of mobilized fatty acids to peroxidation. A decrease in fasting MDA excretion was observed in rats previously fed a high level of antioxidants (vitamin E+BHT+vitamin C) vs a normal level of vitamin E. MDA excretion increased following adriamycin and CCl4 administration. No increase was observed following short‐term feeding of a choline‐methionine‐deficient diet, which has been reported to increase peroxidation of rat liver nuclear lipids.This study provides further evidience that urinary MDA can serve as a useful indicator of lipid peroxidation in vivo when peroxidation of dietary lipids is precluded.
An improved method for the colorimetric assay of lipase activity using an optically clear medium
Authors: Renard G. , Grimaud J. , El Zanf A. , Pina M. , Gralle J. 
Published: January 2007

AbstractLipase activity can be spectrophometrically measured in an optically clear medium using long chain fatty thioesters of 1‐mercapto‐2,3‐propanediol or 2‐mercaptoethanol as substrates. With hexamethylphosphoric triamide solutions of these thiosubstrates, the Michaëlis‐Menten constants of lipase fromRhizopus arrhizus were determined. The effects of calcium chloride and of bovine serum albumin on the enzyme activity were established.
Paul Oliver: a selective bibliography, 1952–2005
Authors: FORD ROB 
Published: January 2007

This selective listing concentrates on Paul Oliver's writings on music – therefore, references to books and articles on architecture have been omitted. For reasons of space, Paul's numerous record, book and concert reviews, published in journals such as Jazz Monthly, Audio & Record Review, Melody Maker, and Blues Unlimited, have not been included. For similar reasons, I have chosen not to include the many entries Paul contributed to the following encyclopedias: Jazz on Record: A Critical Guide to the First 50 Years, 1917–1967, ed. A. McCarthy, A. Morgan, M. Harrison and P. Oliver (London, Hanover, 1968); The New Grove Dictionary of Music and Musicians, ed. S. Sadie (London, Macmillan, 1980); and The New Grove Dictionary of Jazz, ed. B. Kernfeld (London, Macmillan, 1994). However, I have included entries from The Continuum Encyclopedia of Popular Music of the World, as examples of Paul's more recent writing. Also omitted are details of the radio programmes made for the BBC from the mid 1950s to the late 1990s.Thank you to Paul for his help with this bibliography.
Protein and Cellular Engineering with Unnatural Amino Acids
Authors: Liao Jiayu 
Published: January 2007

AbstractProteins are the central functional constituents in all living organisms ranging from viruses, bacteria, yeast, and plants to mammals. All of these biopolymers that are formed by natural biosynthetic pathways are composed of a genetically determined sequence of the 20 so‐called natural amino acids. The physical and chemical properties of proteins are a reflection of the side chains of each of the component amino acids. However, for some purposes it would be very desireable to have amino acids with side chains of various selected physical chemical properties, such as a keto group, a crosslinker, or a NMR probe group, incorporated into the protein. Although chemical and biochemical methods for modifying amino acid moieties in proteins have been achieved, recent successes in incorporating unnatural amino acids in vivo open entirely new avenues for determining protein functions in vivo and for the creation of unnatural proteins with novel functionalities. Several examples by employing the novel activity of unnatural amino acids have shown significant roles in both basic research and biotechnology.
A Potential Portal Flow in the Inner Ear
Authors: Friis Morten , Qvortrup Klaus 
Published: January 2007

AbstractObjectives/Hypothesis: The aim of the present study was to visualize the flow direction of blood in the extraosseous part of the vein of the vestibular aqueduct (VVA) and to explore the effect of an induced obstruction in the distal part of the VVA before it merges with the sigmoid sinus. The endolymphatic sac has been implicated as a potential endocrine gland, which venules drain to the VVA. A reversal of the direction of flow in the VVA toward the inner ear could, through vestibular arteriovenous anastomosis, cause portal circulation in the inner ear.Study Design: The authors conducted an experimental animal study using in vivo fluorescence microscopy.Results: Obstructing the distal part of the VVA just before it empties into the sigmoid sinus immediately reverses the flow of blood in the VVA toward the inner ear.Conclusions: After an obstruction of the VVA, the drained venous blood from the endolymphatic sac may enter a portal circulation in the inner ear, which could cause disturbances in the endolymph homeostasis and potentially symptoms as seen in Meniere disease.
A sirtuin in the African trypanosome is involved in both DNA repair and telomeric gene silencing but is not required for antigenic variation
Authors: Alsford Sam , Kawahara Taemi , Isamah Cyril , Horn David 
Published: January 2007

Summary Silent information regulator 2 (Sir2)‐related proteins or sirtuins function as NAD+‐dependent deacetylases or ADP ribosylases that target a range of substrates, thereby influencing chromatin structure and a diverse range of other biological functions. Genes encoding three Sir2‐related proteins (SIR2rp1–3) have been identified in the parasitic trypanosomatids, early branching protozoa with no previously reported transcriptional silencing machinery. Here we show that, in the mammalian‐infective bloodstream‐stage of the African trypanosome, Trypanosoma brucei, SIR2rp1 localizes to the nucleus while SIR2rp2 and SIR2rp3 are both mitochondrial proteins. The nuclear protein, SIR2rp1, controls DNA repair and repression of RNA polymerase I‐mediated expression immediately adjacent to telomeres. Antigenic variation, however, which involves the silencing and Pol I‐mediated transcriptional switching of subtelomeric variant surface glycoprotein genes, continues to operate independent of SIR2rp1.
A direct estimate of JIc from the load versus load‐line displacement record
Authors: PEHRSON B. P. , LANDES J. D. 
Published: January 2007

ABSTRACTThe purpose of this study is to examine the current standard fracture toughness test procedure to determine if there could be an easier method to get a JIc value from the test record. The current method for determining JIc involves a detailed computational and construction procedure. The objective in this study is to simplify the analysis for the determination of JIc.The results of this study show that the load and displacement record for a fracture toughness test can be used to directly estimate a JQ value, a provisional value for fracture toughness, JIc. The J value taken at the maximum load point can be used along with an adjustment factor to estimate a JQ value. This JQ estimate is close to the one obtained from the construction procedure of ASTM Standard E 1820. When a unit‐sized specimen is tested, that is, a specimen with a width of 50 mm and a thickness of 25 mm the maximum load point provides a direct estimate of JQ. Other sizes require a size adjustment factor, which is simply a square root relationship between the width of the test specimen and a unit width. The proposed new method of estimating JQ is simple in concept and requires a minimum number of calculations. It appears to produce values of JQ which are comparable to those obtained from the ASTM E1820 construction procedure and may produce less scatter.
Ischaemia: a pathogenetic clue in diversion colitis?
Authors: Villanacci V. , Talbot I. C. , Rossi E. , Bassotti G. 
Published: January 2007

AbstractObjective   It is not common that, after diversion of the faecal stream by a colostomy, the defunctioned colon develops colitis. The pathogenesis of this colitis is still unclear and it has been proposed that ischaemia may play a major role. Our aim is to look for signs of ischaemia in a group of patients developing colitis after diversion colostomy for various causes.Method   Surgical specimens from 32 patients resected for colitis developed after diverting colostomy were examined with routine (haematoxylin–eosin) and Elastic‐Van Gieson and Perls’ stains.Results   The histological features related to mucosal crypt architecture, crypt epithelium and inflammation were mild, non specific or related to the underlying disease. Fibrosis was present in 21 (65.6%) patients, superficial coagulative necrosis was found in 18 (56%) patients, splitting and/or thickening of muscularis mucosae was present in 20 (62%) patients. The vessels were substantially normal or ectasic without thrombi or alterations in the wall. Evident ischaemia with coagulative necrosis, submucosal oedema and focal fibrosis was detected in only two (6%) patients and an intermediate picture between acute and chronic ischaemia was present in 16 (50%) patients.Conclusion   It is possible that ischaemia plays some role in the pathogenesis of diversion colitis; however, further studies are needed to firmly establish its role.
Eating fast food: attitudes of high‐school students
Authors: Mattsson Jan , Helmersson Helge 
Published: January 2007

AbstractAlarmingly consistent recent research shows that industrially produced foods such as fast food contain compounds that add to obesity and high cholesterol among young people. Less physical activity and a higher propensity to eat ready‐made food (in Sweden and internationally) have aggravated the health situation for the young generation. They also have become ‘addicted’ to sugar by the consumption of lemonade and other sweet drinks that are often served in conjunction with fast food. Food consumption patterns are highly cultural, and, once formed in early years, they become difficult to change. The findings of this study, which was based on a small sample of written accounts and transcribed interviews, indicate that high‐school students in Sweden are well aware of the good and bad attributes of fast food, such as: speed, convenience, fat and sugar. Clear differences in attitude were found between male and female students: female students view fast food in a broad food chain context, whereas male students concentrate on fast eating and satiety.
Critical role of sodium in cytosolic [Ca2+] elevations in cultured hippocampal CA1 neurons during anoxic depolarization
Authors: Kiedrowski Lech 
Published: January 2007

AbstractAlthough the extent of ischemic brain damage is directly proportional to the duration of anoxic depolarization (AD), the mechanism of cytosolic [Ca2+] ([Ca2+]c) elevation during AD is poorly understood. To address the mechanism in this study, [Ca2+]c was monitored in cultured rat hippocampal CA1 neurons loaded with a Ca‐sensitive dye, fura‐2FF, and exposed to an AD‐simulating medium containing (in mmol/L): K+ 65, Na+ 50, Ca2+ 0.13, glutamate 0.1, and pH reduced to 6.6. Application of this medium promptly elevated [Ca2+]c to about 30 µmol/L, but only if oxygen was removed, the respiratory chain was inhibited, or if the mitochondria were uncoupled. These high [Ca2+]c elevations depended on external Ca2+ and could not be prevented by inhibiting NMDA or α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionate (AMPA)/kainate receptors, or gadolinium‐sensitive channels. However, they could be prevented by removing external Na+ or simultaneously inhibiting NMDA and AMPA/kainate receptors; 2‐[2‐[4‐(4‐nitrobenzyloxy)phenyl]ethyl]isothiourea methanesulfonate (KB‐R7943), an inhibitor of plasmalemmal Na+/Ca2+ exchanger, partly suppressed them. The data indicate that the [Ca2+]c elevations to 30 µmol/L during AD result from Na+ influx. Activation of either NMDA or AMPA/kainate channels provides adequate Na+ influx to induce these [Ca2+]c elevations, which are mediated by KB‐R7943‐sensitive and KB‐R7943‐resistant mechanisms.
Do Food and Dose Timing Affect the Efficacy of Sildenafil? A Randomized Placebo-Controlled Study
Authors: Zinner Norman 
Published: January 2007

ABSTRACT

Introduction
Sildenafil citrate has been used worldwide by men with erectile dysfunction. The prescribing information for sildenafil suggests ingestion 1 hour before sexual activity and also notes reduced maximum plasma concentration and delayed time to maximum concentration following ingestion with a high-fat meal. The clinical impact of coingestion of food and these factors has never been evaluated.

Aim
To determine, using a naturalistic study design, whether sildenafil taken 1 hour before or during a meal compared with usual ingestion 30–60 minutes before sexual activity affects efficacy or patient satisfaction.

Methods
After a 1–2-week washout, 48 men (29–79 years old), currently satisfied with sildenafil, followed each of four regimens: (A) sildenafil 1 hour before a meal and placebo 30–60 minutes before planned coitus vs. (B) placebo 1 hour before a meal and sildenafil 30–60 minutes before coitus; and (C) sildenafil during a meal and placebo 30–60 minutes before coitus vs. (D) placebo during a meal and sildenafil 30–60 minutes before coitus. Subjects were not instructed to change their regular dietary habits during the course of the study.

Main Outcome Measures
Change from baseline in the International Index of Erectile Function (IIEF) Erectile Function (EF) domain score, responses to Sexual Encounter Profile (SEP) questions 2 (erection sufficient for penetration) and 3 (erection sufficient to complete intercourse), and measures of patient preference and satisfaction.

Results
Mean changes in IIEF-EF domain scores were 11.4 for regimens A and B and 11.2 for C and D. Positive SEP2 responses were recorded for 93.9% and 91.8% of intercourse attempts in A and B and 91.4% and 92.6% in C and D. Corresponding results for SEP3 were 84.7% and 85.9%, and 83.4% and 87.5%, respectively. There were no significant differences between pairs of treatments on satisfaction. The time between sildenafil ingestion and intercourse attempt (0–0.5 to &gt;10 hours) had no significant effect on responses to SEP2, but decreased responses to SEP3 from a maximum of 92.8% at 1.5–2 hours to 81.6% at more than 10 hours (P = 0.003).

Conclusion
No significant loss of efficacy occurs when sildenafil is taken shortly before or with a meal. The duration of action for sildenafil may exceed 10 hours.
Test for Detection of Disease-Associated Prion Aggregate in the Blood of Infected but Asymptomatic Animals
Authors: Chang Binggong , Cheng Xin , Yin Shaoman , Pan Tao , Zhang Hongtao , Wong Poki , Kang Shin-Chung , Xiao Fan , Yan Huimin , Li Chaoyang , Wolfe Lisa L. , Miller Michael W. , Wisniewski Thomas , Greene Mark I. , Sy Man-Sun 
Published: January 2007

ABSTRACT

We have developed a sensitive in vitro assay for detecting disease-associated prion aggregates by combining an aggregation-specific enzyme-linked immunosorbent assay (AS-ELISA) with the fluorescent amplification catalyzed by T7 RNA polymerase technique (FACTT). The new assay, named aggregation-specific FACTT (AS-FACTT), is much more sensitive than AS-ELISA and could detect prion aggregates in the brain of mice as early as 7 days after an intraperitoneal inoculation of PrP
Sc
. However, AS-FACTT was still unable to detect prion aggregates in blood of infected mice. To further improve the detection limit of AS-FACTT, we added an additional prion amplification step (Am) and developed a third-generation assay, termed Am-A-FACTT. Am-A-FACTT has 100% sensitivity and specificity in detecting disease-associated prion aggregates in blood of infected mice at late but still asymptomatic stages of disease. At a very early stage, Am-A-FACTT had a sensitivity of 50% and a specificity of 100%. Most importantly, Am-A-FACTT also detects prion aggregates in blood of mule deer infected with the agent causing a naturally occurring prion disease, chronic wasting disease. Application of this assay to cattle, sheep, and humans could safeguard food supplies and prevent human contagion.
Use of the Agilent 2100 Bioanalyzer for Rapid and Reproducible Molecular Typing of
Streptococcus pneumoniae
Authors: Hathaway Lucy J. , Brugger Silvio , Martynova Alina , Aebi Suzanne , Mühlemann Kathrin 
Published: January 2007

ABSTRACT

Restriction fragment length polymorphism (RFLP) analysis is an economic and fast technique for molecular typing but has the drawback of difficulties in accurately sizing DNA fragments and comparing banding patterns on agarose gels. We aimed to improve RFLP for typing of the important human pathogen
Streptococcus pneumoniae
and to compare the results with the commonly used typing techniques of pulsed-field gel electrophoresis and multilocus sequence typing. We designed primers to amplify a noncoding region adjacent to the pneumolysin gene. The PCR product was digested separately with six restriction endonucleases, and the DNA fragments were analyzed using an Agilent 2100 bioanalyzer for accurate sizing. The combined RFLP results for all enzymes allowed us to assign each of the 47 clinical isolates of
S. pneumoniae
tested to one of 33 RFLP types. RFLP analyzed using the bioanalyzer allowed discrimination between strains similar to that obtained by the more commonly used techniques of pulsed-field gel electrophoresis, which discriminated between 34 types, and multilocus sequence typing, which discriminated between 35 types, but more quickly and with less expense. RFLP of a noncoding region using the Agilent 2100 bioanalyzer could be a useful addition to the molecular typing techniques in current use for
S. pneumoniae
, especially as a first screen of a local population.
Theory of Lethal Mutagenesis for Viruses
Authors: Bull J. J. , Sanjuán R. , Wilke C. O. 
Published: January 2007

ABSTRACT
Mutation is the basis of adaptation. Yet, most mutations are detrimental, and elevating mutation rates will impair a population's fitness in the short term. The latter realization has led to the concept of lethal mutagenesis for curing viral infections, and work with drugs such as ribavirin has supported this perspective. As yet, there is no formal theory of lethal mutagenesis, although reference is commonly made to Eigen's error catastrophe theory. Here, we propose a theory of lethal mutagenesis. With an obvious parallel to the epidemiological threshold for eradication of a disease, a sufficient condition for lethal mutagenesis is that each viral genotype produces, on average, less than one progeny virus that goes on to infect a new cell. The extinction threshold involves an evolutionary component based on the mutation rate, but it also includes an ecological component, so the threshold cannot be calculated from the mutation rate alone. The genetic evolution of a large population undergoing mutagenesis is independent of whether the population is declining or stable, so there is no runaway accumulation of mutations or genetic signature for lethal mutagenesis that distinguishes it from a level of mutagenesis under which the population is maintained. To detect lethal mutagenesis, accurate measurements of the genome-wide mutation rate and the number of progeny per infected cell that go on to infect new cells are needed. We discuss three methods for estimating the former. Estimating the latter is more challenging, but broad limits to this estimate may be feasible.
High-Frequency Epigenetic Repression and Silencing of Retroviruses Can Be Antagonized by Histone Deacetylase Inhibitors and Transcriptional Activators, but Uniform Reactivation in Cell Clones Is Restricted by Additional Mechanisms
Authors: Katz Richard A. , Jack-Scott Emily , Narezkina Anna , Palagin Ivan , Boimel Pamela , Kulkosky Joseph , Nicolas Emmanuelle , Greger James G. , Skalka Anna Marie 
Published: January 2007

ABSTRACT
Integrated retroviral DNA is subject to epigenetic gene silencing, but the viral and host cell properties that influence initiation, maintenance, and reactivation are not fully understood. Here we describe rapid and high-frequency epigenetic repression and silencing of integrated avian sarcoma virus (ASV)-based vector DNAs in human HeLa cells. Initial studies utilized a vector carrying the strong human cytomegalovirus (hCMV) immediate-early (IE) promoter to drive expression of a green fluorescent protein (GFP) reporter gene, and cells were sorted into two populations based on GFP expression [GFP(+) and GFP(−)]. Two potent epigenetic effects were observed: (i) a very broad distribution of GFP intensities among cells in the GFP(+) population as well as individual GFP(+) clones and (ii) high-frequency GFP reporter gene silencing in GFP(−) cells. We previously showed that histone deacetylases (HDACs) can associate with ASV DNA soon after infection and may act to repress viral transcription at the level of chromatin. Consistent with this finding, we report here that treatment with the histone deacetylase inhibitor trichostatin A (TSA) induces GFP activation in GFP(−) cells and can also increase GFP expression in GFP(+) cells. In the case of the GFP(−) populations, we found that after removal of TSA, GFP silencing was reestablished in a subset of cells. We used that finding to enrich for stable GFP(−) cell populations in which viral GFP reporter expression could be reactivated by TSA; furthermore, we found that the ability to isolate such populations was independent of the promoter driving the GFP gene. In such enriched cultures, hCMV IE-driven, but not the viral long terminal repeat-driven, silent GFP reporter expression could be reactivated by the transcriptional activator prostratin. Microscopy-based studies using synchronized cells revealed variegated reactivation in cell clones, indicating that secondary epigenetic effects can restrict reactivation from silencing. Furthermore we found that entry into S phase was not required for reactivation. We conclude that HDACs can act rapidly to initiate and maintain promoter-independent retroviral epigenetic repression and silencing but that reactivation can be restricted by additional mechanisms.