bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of P2 receptors for purine and pyrimidine nucleotides in human placental cotyledons
Authors: Ralevic Vera , Burrell Stephen , Kingdom John , Burnstock Geoffrey 
Published: August 2006

The aim of this study was to characterize P2 receptors in the arterial vascular bed of human perfused placental cotyledons. Vasoconstrictor responses to bolus injections of purine and pyrimidine nucleotides were tested at basal tone, and vasodilator responses in preparations with tone raised by perfusion with prostaglandin F2α (PGF2α; 10–50nm).
At basal tone, bolus injections of the P2X‐selective agonist α,β‐methylene ATP (α,β‐meATP; 0.5–500nmol) elicited dose‐dependent vasoconstriction. ATP (0.005–5μmol) also elicited dose‐dependent vasoconstriction, but was less potent than α,β‐meATP. Vasoconstriction was also elicited by other nucleotides, but only at the highest dose tested (5μmol): UTP >CTP=ITP (n=6). GTP and TTP did not cause vasoconstriction.
Constrictor responses to bolus injections of α,β‐meATP were resistant to desensitization and were not significantly affected when carried out in the presence of 1μm α,β‐meATP added to the perfusate. However, responses to bolus injections of α,β‐meATP were partially blocked by perfusion with 10μm α,β‐meATP. In contrast, responses to ATP and UTP were unaffected by 10μm α,β‐meATP. The P2X receptor antagonist pyridoxalphosphate‐6‐azophenyl‐2′,4′‐disulphonic acid (PPADS; 10 and 100μm) had no significant effect on vasoconstriction mediated by α,β‐meATP and ATP.
Removal of the endothelium had no significant effect on constrictor responses to α,β‐meATP, ATP and UTP. Inhibition of nitric oxide (NO) synthesis with NG‐nitro‐l‐arginine methyl ester (l‐NAME; 100μm) had no significant effect on vasoconstriction to ATP and α,β‐meATP.
In preparations with tone raised with PGF2α (10–50nm) vasodilatation was elicited by nucleotides with the following order of potency: 2MeSATP=ADP >>ATP >UTP >CTP=GTP=ITP=TTP. pD2 values were: 2MeSATP, 10.03±0.26 (n=7); ADP, 9.97±0.40 (n=5); ATP, 8.89±0.18 (n=7); UTP, 7.79±0.35 (n=7). Maximal responses to 2MeSATP and ADP were similar and were approximately 40% greater than maximal responses to ATP and UTP.
Vasodilator responses to nucleotides were abolished by l‐NAME (100μm) and by removal of the endothelium.
In conclusion, contractile responses mediated by α,β‐meATP and ATP in human placental smooth muscle are resistant to desensitization and insensitive to PPADS and, thus, show a dissimilar pharmacological profile to the classic smooth muscle P2X1 receptor. There may be two subtypes of smooth muscle P2 receptor based on differential antagonism of α,β‐meATP and ATP with α,β‐meATP. A smooth muscle P2 receptor mediates vasoconstriction to UTP, and may indicate a further subtype. Endothelium‐dependent, NO‐dependent, vasodilatation to 2MeSATP and ADP may be mediated by P2Y1 receptors, while endothelial P2Y2 receptors are likely to mediate NO‐dependent relaxation to ATP and UTP.
Effects of β2‐agonist‐ and dexamethasone‐treatment on relaxation and regulation of β‐adrenoceptors in human bronchi and lung tissue
Authors: Hauck R. W. , Harth M , Schulz C , Präuer H , Böhm M , Schömig A 
Published: August 2006

Long‐term treatment with β2‐adrenoceptor agonists can lead to a decreased therapeutic efficacy of bronchodilatation in patients with obstructive pulmonary disease. In order to examine whether or not this is due to β‐adrenoceptor desensitization, human bronchial muscle relaxation was studied in isolated bronchial rings after pretreatment with β2‐adrenoceptor agonists. Additionally, the influence of pretreatment with dexamethasone on desensitization was studied.
The effect of β2‐agonist incubation alone and after coincubation with dexamethasone on density and affinity of β‐adrenoceptors was investigated by radioligand binding experiments.
In human isolated bronchi, isoprenaline induces a time‐ and concentration‐dependent β‐adrenoceptor desensitization as judged from maximal reduction in potency by a factor of 7 and reduction of 73±4% in efficacy of isoprenaline to relax human bronchial smooth muscle.
After an incubation period of 60 min with 100 μmol l−1 terbutaline, a significant decline in its relaxing efficacy (81±8%) and potency (by a factor 5.5) occurred.
Incubation with 30 μmol l−1 isoprenaline for 60 min did not impair the maximal effect of a subsequent aminophylline response but led to an increase in potency (factor 4.4).
Coincubation of dexamethasone with isoprenaline (120 min; 30 μmol l−1) preserved the effect of isoprenaline on relaxation (129±15%).
In radioligand binding experiments, pretreatment of lung tissue for 60 min with isoprenaline (30 μmol l−1) resulted in a decrease in β‐adrenoceptor binding sites (Bmax) to 64±1.6% (P<0.05), while the antagonist affinity (KD) for [3H]‐CGP‐12177 remained unchanged.
In contrast, radioligand binding studies on lung tissue pretreated with either dexamethasone (30 μmol l−1) or isoprenaline (30 μmol l−1) plus dexamethasone (30 μmol l−1) for 120 min did not lead to a significant change of Bmax (160±22.1% vs 142.3±28.7%) or KD (5.0 nmol l−1 vs 3.5 nmol l−1) compared to the controls.
In conclusion, pretreatment of human bronchi with β‐adrenoceptor agonists leads to functional desensitization and, in lung tissue, to down‐regulation of β‐adrenoceptors. This effect can be counteracted by additional administration of dexamethasone. Our model of desensitization has proved useful for the identification of mechanisms of β‐adrenoceptor desensitization and could be relevant for the evaluation of therapeutic strategies to counteract undesirable effects of long‐term β‐adrenoceptor stimulation.

British Journal of Pharmacology (1997) 121, 1523–1530; doi:10.1038/sj.bjp.0701289
Imipenem Resistance Among Pseudomonas aeruginosa Isolates Risk Factors for Infection and Impact of Resistance on Clinical and Economic Outcomes
Authors: Lautenbach Ebbing , Weiner Mark G. , Nachamkin Irving , Bilker Warren B. , Sheridan Angela , Fishman Neil O. 
Published: August 2006

Objectives.To identify risk factors for infection with imipenem-resistant Pseudomonas aeruginosa and determine the impact of imipenem resistance on clinical and economic outcomes among patients infected with P. aeruginosa.Designs.An ecologic study, a case-control study, and a retrospective cohort study.Setting.A 625-bed tertiary care medical center.Patients.All patients who had an inpatient clinical culture positive for P. aeruginosa between January 1, 1999, and December 31, 2000.Results.From 1991 through 2000, the annual prevalence of imipenem resistance among P. aeruginosa isolates increased significantly (P<.001 by the χ2 test for trend). Among 879 patients infected with P. aeruginosa during 1999-2000, a total of 142 had imipenem-resistant P. aeruginosa infection (the case group), whereas 737 had imipenem-susceptible P. aeruginosa infection (the control group). The only independent risk factor for imipenem-resistant P. aeruginosa infection was prior fluoroquinolone use (adjusted odds ratio, 2.52 [95% confidence interval {CI}, 1.61-3.92]; P<.001). Compared with patients infected with imipenem-susceptible P. aeruginosa, patients infected with imipenem-resistant P. aeruginosa had longer subsequent hospitalization durations (15.5 days vs 9 days; P = .02) and greater hospital costs ($81,330 vs $48,381; P<.001). The mortality rate among patients infected with imipenem-resistant P. aeruginosa was 31.1%, compared with 16.7% for patients infected with imipenem-susceptible P. aeruginosa (relative risk, 1.86 [95% CI, 1.38-2.51]; P<.001). In multivariable analyses, there remained an independent association between infection with imipenem-resistant P. aeruginosa and mortality.Conclusions.The prevalence of imipenem resistance among P. aeruginosa strains has increased markedly in recent years and has had a significant impact on both clinical and economic outcomes. Our results suggest that curtailing use of other antibiotics (particularly fluoroquinolones) may be important in attempts to curb further emergence of imipenem resistance.
An application for assessing quality of RNA hybridized to Affymetrix GeneChips
Authors: Archer Kellie J. , Guennel Tobias 
Published: August 2006

Abstract
Summary: This paper describes a stand-alone application for estimating the 3′ to 5′ ratio by fitting a mixed effects model to the interior pixel intensities of perfect match probes for selected control probe sets from an Affymetrix *.DAT file. The effectiveness of this method was demonstrated previously by an application of the method to two microarray datasets for which external verification of RNA quality was known. This application provides a more objective assessment of sample quality in that both a point estimate and 95% confidence interval about the 3′ to 5′ ratio are provided.
Availability: The software and installation instructions are freely available for download at
Contact: kjarcher@vcu.edu
TheturnipMutant of Arabidopsis Reveals ThatLEAFY COTYLEDON1Expression Mediates the Effects of Auxin and Sugars to Promote Embryonic Cell Identity
Authors: Casson Stuart A. , Lindsey Keith 
Published: August 2006

AbstractThe transition from embryonic to vegetative growth marks an important developmental stage in the plant life cycle. The turnip (tnp) mutant was identified in a screen for modifiers of POLARIS expression, a gene required for normal root growth. Mapping and molecular characterization of tnp shows that it represents a gain-of-function mutant of LEAFY COTYLEDON1 (LEC1), due to a promoter mutation. This results in the ectopic expression of LEC1, but not of other LEC genes, in vegetative tissues. The LEC class of genes are known regulators of embryogenesis, involved in the control of embryonic cell identity by currently unknown mechanisms. Activation of the LEC-dependent pathway in tnp leads to the loss of hypocotyl epidermal cell marker expression and loss of SCARECROW expression in the endodermis, the ectopic accumulation of starch and lipids, and the up-regulation of early and late embryonic genes. tnp also shows partial deetiolation during dark growth. Penetrance of the mutant phenotype is strongly enhanced in the presence of exogenous auxin and sugars, but not by gibberellin or abscisic acid, and is antagonized by cytokinin. We propose that the role of LEC1 in embryonic cell fate control requires auxin and sucrose to promote cell division and embryonic differentiation.
Interaction between Nitric Oxide and Ethylene in the Induction of Alternative Oxidase in Ozone-Treated Tobacco Plants
Authors: Ederli Luisa , Morettini Roberta , Borgogni Andrea , Wasternack Claus , Miersch Otto , Reale Lara , Ferranti Francesco , Tosti Nicola , Pasqualini Stefania 
Published: August 2006

Abstract
The higher plant mitochondrial electron transport chain contains, in addition to the cytochrome chain, an alternative pathway that terminates with a single homodimeric protein, the alternative oxidase (AOX). We recorded temporary inhibition of cytochrome capacity respiration and activation of AOX pathway capacity in tobacco plants (Nicotiana tabacum L. cv BelW3) fumigated with ozone (O3). The AOX1a gene was used as a molecular probe to investigate its regulation by signal molecules such as hydrogen peroxide, nitric oxide (NO), ethylene (ET), salicylic acid, and jasmonic acid (JA), all of them reported to be involved in the O3 response. Fumigation leads to accumulation of hydrogen peroxide in mitochondria and early accumulation of NO in leaf tissues. Although ET accumulation was high in leaf tissues 5 h after the start of O3 fumigation, it declined during the recovery period. There were no differences in the JA and 12-oxo-phytodienoic acid levels of treated and untreated plants. NO, JA, and ET induced AOX1a mRNA accumulation. Using pharmacological inhibition of ET and NO, we demonstrate that both NO- and ET-dependent pathways are required for O3-induced up-regulation of AOX1a. However, only NO is indispensable for the activation of AOX1a gene expression.
White blood cell sister chromatid exchange among a sample of Thai subjects exposed to toluene, an observation
Authors: Wiwanitkit Viroj , Suwansaksri Jamsai , Soogarun Suphan 
Published: August 2006

SummaryThere is a particular concern with toluene because some research has indicated that toluene exposure could result in chronic toxicity including mutagenesis and carcinogenesis. This study aimed to determine the rate of sister chromatid exchanges (SCE), a marker for genotoxicity, and its correlation to the classical urine biomarker for toluene exposure, urine hippuric acid, among a sample of Thai exposed subjects. A total of 26 police (all males) were included in this study. The average (mean ± SD) urine hippuric acid level in these police was 0.8 ± 0.4 mg/g creatinine. The average (mean ± SD) SCE level in these police was 4.5 ± 1.0/cell. The average SCE among the police with high urine hippuric acid levels was non‐significantly higher than the average SCE level of those without (P = 0.41). This implies that the cytogenetic response to toluene was not different between the subjects with and without high toluene exposure. High exposure to toluene seems not to be related to high SCE.
Effect of Different Temperatures on Various Bacteria Isolated from Frozen Meat Piesa
Authors: KERELUK K. , PETERSON A. C. , GUNDERSON M. F. 
Published: August 2006

SUMMARYThe effect of temperature, particularly storage temperature, is one of the most important factors in controlling microbial populations of frozen foods. Adequate temperature control of frozen foods should limit the growth of microorganisms and insure maintenance of original quality and wholesomeness. This investigation was undertaken to show that correct storage temperatures do inhibit the growth of bacteria which might be considered as the source of potential public health hazard, while certain saprophytic species are able to survive and grow well at the, same low temperatures. The cultures were all isolated from chicken pies.Bacterial counts were determined by plating techniques on Brain Heart Infusion (BHI) agar after various time intervals up to 30 days at ‐13°, 0°, 5°, 10°, 20° and 37° C, using both BHI broth and chicken gravy as media. Very similar results were obtained in the two media. Escherichia coli and Streptococcus faecalis had a minimum growth temperature between 5° and 10° C for active reproduction. A minimum growth temperature between 5° and 10° C was observed for the culture of Staphylococcus aureus. Of two cultures representing variants of Pseudomonas fluorescens, one culture followed the growth‐temperature pattern shown by the previously mentioned organisms and failed to grow at or below 5° C. The other P. fluorescens culture grew rapidly at 5° C. Ability to grow at low temperatures is a constitutive characteristic of the organism and is not common to all types of bacteria. At refrigerator temperatures, the growth of the psychrophilic saprophytic species tested completely outstripped the growth of several bacteria of public health significance. This indicates the great likelihood that a frozen food on defrosting, particularly in a refrigerator, would become completely unacceptable, due to the development of off flavors and odors and deteriorated physical appearance before it became a health hazard.
Media for Detecting Pectolytic Gram‐Negative Bacteria Associated with the Softening of Cucumbers, Olives, and Other Plant Tissuesa
Authors: KING A. DOUGLAS , VAUGHN REESE H. 
Published: August 2006

SUMMARYThe limitations of cosine methylene blue or basic fuchsin polypectate gels prompted further investigations to develop a selective pectate gel that could be used to enumerate or isolate gram‐negative pectolytic bacteria even when they composed a minor portion of the microbial population.Crystal violet and brilliant green with bile proved the most effective of several selective agents studied. Of the two, crystal violet was much less inhibitory. Actidione, 10 mg per L added after sterilization, is helpful in the control of growth of molds and yeasts on this medium.The crystal violet medium has a productivity comparable to that of standard plate‐count agar when pure cultures are used. It was successfully used to enumerate known populations of pectolytic gram‐negative bacteria among mixed populations of other nonpectolytic gram‐negative and ‐positive bacteria. It is also being used routinely for enumeration and isolation of pectolytic gram‐negative bacteria from natural sources.Thus far, pectolytic bacteria belonging to 5 genera, including Aerobacter, Escherichia, Paracolobactrum, Aeromonas, and Achromobacter, have been isolated by use of the crystal violet gel.
Production of Irradiation Odors from Beef Protein Fractions and Their Derivatives
Authors: HEDIN P. A. , KURTZ GEORGE W. , KOCH ROBERT B. 
Published: August 2006

SUMMARYThis report contains information on some odors produced by gamma irradiation of several beef protein fractions and their derivatives. The odor was shown to vary with protein class, with molecular weight and electric charge, with the medium, and with the availability of functional groups. The unorthodox physical and chemical responses of an odor characterized as a “wet dog” odor are contrasted with those of a “wet chicken feather” odor. Of chief significance is the large variety of irradiated odors that can be produced from a single starting material as conditions are varied.
Sugar Sulfonates and Their Behavior
Authors: BRAVEMAN J. B. S. , KOPELMAN J. 
Published: August 2006

SUMMARYNew crystalline bisulfite addition products of mannose and galactose were prepared, namely α‐hydroxy‐galactose sulfonate, and α‐hydroxy‐mannose sulfonate, and their properties studied. In addition, the rates of dissociation of these sulfonates were studied, and further evidence is presented to show that these products have an open‐chain configuration.The evidence obtained supports the theory put forward previously by one of the authors, namely, that sulfur dioxide and sulfates interact only with the open‐chain aldehyde configuration of the sugars when the cyclic forms of the sugars open during their mutarotation. A maltose sulfonate was prepared in which only half of the molecule was capable of interaction with sulfites. This addition product failed to crystallize. It is probable that the same mechanism is of importance in interpreting the browning phenomena during the Maillard reaction.
Spectral Measurements of Hematin Pigments of Cooked and Cured Meats
Authors: TAPPEL A. L. 
Published: August 2006

SUMMARYReflectance spectra, low temperature absorption spectra and difference absorption spectra are used for the identification of the hematin pigments of cooked and cooked cured meats. These spectra provide more critical identification of the cooked and cured meats as hemochromes.
Fatty Acids of the Lipids of Vegetables. I. Peas (Pisum sativum)a
Authors: LEE FRANK A. , MATTICK LEONARD R. 
Published: August 2006

SUMMARYChanges taking place in the fatty acids of the lipid material of the edible pea were investigated. Peas were held 1 year in storage at –17.8°C in the raw and enzyme‐inactivated condition, to determine changes taking place in the fatty acids. Under these conditions, all of the several fatty acids in the phospholipid fraction showed large losses in the raw as contrasted with the enzyme‐inactivated samples. At the same time the neutral fats in the same sample showed losses for all the unsaturated fatty acids in the raw when contrasted with those extracted from the enzyme‐inactivated material. The fatty acids in the neutral fat and the free fatty acids of the raw material showed a net gain in the total quantity of palmitic acid. It seems possible that this increase came from the three unsaturated C18 acids.
Fractionation of the Component(s) Responsible for Sex Odor/Flavor in Porka,b,c
Authors: CRAIG H. B. , PEARSON A. M. , WEBB N. B. 
Published: August 2006

SUMMARYSex odor/flavor in pork was produced when fat, lean (with fat), and most organs from a boar were heated in a skillet or in boiling water. Odor seemed not to be entirely absent in boar fat at body temperature, although volatilization appeared to occur to a much greater extent at approx. 100–108° C. Sex odor was found to be water‐insoluble, ether‐soluble, and definitely associated with the fatty tissues of boars. It was absent in rehydrated moisture‐free, fat‐free lean. Distillation methods proved unsatisfactory for collecting the sex odor components in recognizable form, since no consistent and reproducible differences could be detected between boar and barrow fat when collected volatile compounds were analyzed by heat test and gas ehromatography. Cold saponification of boar fat yielded a small quantity of unsaponifiable matter that produced a concentrated, permeating sex odor on exposure to heat. Thus, the agent(s) responsible for sex odor in pork are located in the unsaponifiable material. Cholesterol and squalene were found in this fraction in both boar and barrow fat, but sex odor was not produced when these compounds were heated.
The Composition of Commercially Important Fish Taken From New England Waters.
Authors: BROOKE RICHARD O. , RAVESI ELINOR M. , STEINBERG MAYNARD A. 
Published: August 2006

SUMMARYThe protein, oil, ash, moisture, sodium, and potassium content of samples of butterfish, flounder, pollock, and hake was determined. In addition, length, weight, and fillet yield have been recorded. Fillet yield differed markedly both with species and with the size of the fish. Analysis showed a wide variation in the percentage of oil, not only in butterfish (considered an oily fish) but also in lean fish such as silver hake and flounder. Protein content proved to be consistently higher in pollock than in the other fish. Mineral and oil components showed a much higher percentage in offal than in corresponding fillets. Analysis of variance indicated that significant differences in results were related to the season in which the fish were caught.
Radiation Sterilization of Food.
Authors: SCHMIDT C. F. , NANK W. K. , LECHOWICH R. V. 
Published: August 2006

SUMMARYThe radiation resistance of spores of 6 strains of Type E Clostridium botulinum was determined in a beef stew substrate. The results are evaluated in terms of the minimum dose showing no spoilage for a 2 billion total inoculum level (20 cans each with 100 million spores per can) and in terms of a calculated radiation D value. The mean radiation D value for 6 strains is 0.132 megarad (range 0.125–0.138). A comparison with results for 6 strains of Type A and 5 strains of Type B shows that Type E strains possess about 45–5570 of the resistance to ionizing radiations of Types A and B. It is concluded that any radiation dose for food sterilization based upon the maximum resistance of Type A or B strains would provide ample protection against Type E strains. The unswelled cans at the lowest radiation level showing no spoilage were free of toxin and recoverable Type E spores.
The Flavor of Cucumbers
Authors: FORSS D. A. , DUNSTONE E. A. , RAMSHAW E. H. , STARK W. 
Published: August 2006

SUMMARYNona‐2, 6‐dienal, non‐2‐enal, hex‐2‐enal, and three saturated aliphatic aldehydes were isolated from cucumbers. Quantitative and qualitative aspects of the flavor of nona‐2,6‐dienal and non‐2‐enal were examined.
Chew Count as a Measure of Tenderness of Pork Loins with Various Degrees of Marblinga
Authors: HARRINGTON G. , PEARSON A. M. 
Published: August 2006

SUMMARYSome tasters were more repeatable than others in making chew counts, and were thereby able to discriminate more between loins of differing tenderness. Mean chew counts by six tasters for 36 loins ranged from 25.3 to 47.0, with one exceptional value at 60.0. These showed a high correlation with mean shear values based on 10 shears per loin. On average, an increase of 1 lb in shear value corresponded to an increase of 4 in the chew count in this experiment. Mean chew counts and shear values both showed significant correlations with two measures of marbling fat made on the 36 loins (visual scores and intramuscular fat contents), the less marbled loins being somewhat tougher. On average, an increase of 1% in intramuscular fat corresponded to a decrease of about 1.5 in chew count or 0.4 lb in shear value.