ABSTRACT
Purpose: Published studies have revealed challenges for people with human immunodeficiency virus (HIV) living in rural areas compared to those in urban areas, such as poor access to HIV care, insufficient transportation, and isolation. The purpose of this study was to examine associations between population density and multiple psychosocial and clinical outcomes in the largest cohort of women with HIV (WWH) in the United States. Methods: Women's Interagency HIV Study (WIHS) participants from Southern sites (n = 561) in 2013-2018 were categorized and compared by population density quartiles. The most urban quartile was compared with the most rural quartile in several psychosocial and clinical variables, including HIV viral load suppression, HIV medication adherence, HIV care attendance, depression, internalized HIV stigma, and perceived discrimination in healthcare settings. Results: Although women in the lowest density quartile were unexpectedly more highly resourced, women in that quartile had greater odds of not attending an HIV care visit in the last six months (odds ratio [OR] = 0.64, 95% confidence interval [CI] [0.43-0.95]), yet higher odds for having fully suppressed HIV when compared to women in the highest density quartile (OR = 1.64, 95% CI [1.13-2.38]). Highly urban WWH had greater likelihood of unsuppressed HIV, even after controlling for income, employment, and health insurance, despite reporting greater HIV care adherence and similar medication adherence. Discussion: Further investigation into the reasons for these disparities by population density is needed, and particular clinical attention should be focused on individuals from high population density areas to help maximize their health outcomes.
Subject(s)
HIV Infections , Medication Adherence , Population Density , Rural Population , Humans , Female , HIV Infections/drug therapy , HIV Infections/epidemiology , Adult , Retrospective Studies , Longitudinal Studies , Middle Aged , United States/epidemiology , Medication Adherence/statistics & numerical data , Rural Population/statistics & numerical data , Urban Population/statistics & numerical data , Social Stigma , Viral Load , Health Services Accessibility/statistics & numerical dataABSTRACT
Objective: To assess whether juvenile idiopathic arthritis (JIA) is associated with healthcare utilization and in-hospital complications after total hip or knee arthroplasty (THA/TKA). Method: We used the 1998-2014 US National Inpatient Sample. We performed multivariable-adjusted logistic regression, adjusted for age, race/ethnicity, gender, income, Deyo-Charlson comorbidity index, insurance payer, and the underlying diagnosis. Results: Of the 4 116 485 THAs and 8 127 282 TKAs, 1882 people with JIA had THAs (0.02%) and 1388 had TKAs (0.01%). Compared to people without JIA, people with JIA post-THA and post-TKA had higher odds ratio [OR (95% confidence interval), respectively] of total hospital charges above the median [1.30 (1.05, 1.60) and 1.37 (1.08, 1.74)], length of hospital stay > 3 days [1.64 (1.27, 2.12) and 1.44 (1.07, 1.93)], and discharge to non-home settings [1.37 (1.07, 1.76)] post-THA, but not post-TKA [1.02 (0.77, 1.36)]. People with JIA also had higher OR of transfusion post-TKA [1.92 (1.44, 2.55)], but not post-THA [1.00 (0.77, 1.30)]. Sensitivity analyses that adjusted for hospital characteristics confirmed the main study findings with minimal or no attenuation of OR. Conclusions: People with JIA utilized more healthcare services post-THA/TKA and were more likely to receive transfusions post-TKA. Interventions to reduce the risk of higher resource utilization are needed in people with JIA.
Subject(s)
Arthritis, Juvenile/complications , Arthroplasty, Replacement, Hip/statistics & numerical data , Arthroplasty, Replacement, Knee/statistics & numerical data , Patient Acceptance of Health Care/statistics & numerical data , Postoperative Complications/epidemiology , Adult , Aged , Arthroplasty, Replacement, Hip/adverse effects , Arthroplasty, Replacement, Hip/economics , Arthroplasty, Replacement, Knee/adverse effects , Arthroplasty, Replacement, Knee/economics , Cohort Studies , Female , Humans , Male , Middle Aged , Postoperative Complications/etiology , United States/epidemiologyABSTRACT
OBJECTIVE: The aim of this study was to assess whether lupus is associated with poorer outcomes after primary total hip arthroplasty (THA). METHODS: We used the 1998-2014 US National Inpatient Sample data. Multivariable-adjusted separate logistic regression models assessed the association of lupus with post-operative complications (implant infection, transfusion, THA revision and mortality) and health care utilization outcomes (total hospital charges, discharge to an inpatient facility and length of hospital stay >3 days) post-THA, adjusting for demographics, underlying diagnosis, comorbidity, insurance payer and hospital characteristics, using odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Among 4,116,485 primary THA hospitalizations, 22,557 (0.5%) were in patients with lupus. Patients with lupus were younger and more likely to be female, African-American or Hispanic, living in the South, or to have Medicaid insurance, and had higher comorbidity or lower income. In multivariable-adjusted analyses, the presence of lupus was associated with significantly higher risk of implant infection, transfusion, discharge to an inpatient facility and higher hospital charges above the median, with respective ORs of 1.95 (95% CI, 1.28, 2.97), 1.34 (95% CI, 1.25, 1.43), 1.21 (95% CI, 1.01, 1.44) and 1.38 (95% CI, 1.30, 1.47). Lupus was not significantly associated with the risk of revision, mortality or hospital stay >3 days; the ORs were 1.10 (95% CI, 0.68, 1.78), 0.95 (95% CI, 0.61, 1.47) and 1.06 (95% CI, 0.99, 1.13), respectively. CONCLUSIONS: Lupus was associated with a higher risk of implant infection, transfusion, discharge to an inpatient facility and higher hospital charges post-primary THA. Insight into modifiable factors associated with these outcomes may improve outcomes in patients with lupus undergoing THA.
Subject(s)
Arthroplasty, Replacement, Hip/adverse effects , Length of Stay/statistics & numerical data , Lupus Erythematosus, Systemic/complications , Postoperative Complications/epidemiology , Aged , Aged, 80 and over , Cohort Studies , Databases, Factual , Female , Humans , Logistic Models , Lupus Erythematosus, Systemic/epidemiology , Male , Middle Aged , Multivariate Analysis , Risk Factors , Treatment Outcome , United States/epidemiologyABSTRACT
INTRODUCTION: In June 2012, the government of Canada severely restricted the scope of the Interim Federal Health Program that had hitherto provided coverage for the health care needs of refugee claimants. The Quebec government decided to supplement coverage via the provincial health program. Despite this, we hypothesized that refugee claimant children in Montreal would continue to experience significant difficulties in accessing basic health care. OBJECTIVES: (1) Report the narrative experiences of refugee claimant families who were denied health care services in Montreal following June 2012, (2) describe the predominant barriers to accessing health care services and understanding their impact using thematic analysis and (3) derive concrete recommendations for child health care providers to improve access to care for refugee claimant children. METHODS: Eleven parents recruited from two sites in Montreal participated in semi-structured interviews designed to elicit a narrative account of their experiences seeking health care. Interviews were recorded, transcribed, coded using NVivo software and subjected to thematic analysis. RESULTS: Thematic analysis of the data revealed five themes concerning barriers to health care access: lack of continuous health coverage, health care administrators/providers' lack of understanding of Interim Federal Health Program coverage, refusal of services or fees charged, refugee claimants' lack of understanding about health care rights and services and language barriers, and four themes concerning the impact of denial of care episodes: potential for adverse health outcomes, psychological distress, financial burden and social stigma. CONCLUSION: We propose eight action points for advocacy by Canadian paediatricians to improve access to health care for refugee claimant children in their communities and institutions.
ABSTRACT
Ensuring equitable and fair organ allocation is a central charge of the United Network for Organ Sharing (UNOS) as the Organ Procurement and Transplantation Network (OPTN) through its contract with the Department of Health and Human Services (DHHS). The OPTN/UNOS Board initiated a reassessment of the current allocation system. This paper describes the efforts of the OPTN/UNOS Heart Subcommittee, acting on behalf of the OPTN/UNOS Thoracic Organ Transplantation Committee, to modify the current allocation system. The Subcommittee assessed the limitations of the current three-tiered system, outcomes of patients with status exceptions, emerging ventricular assist device (VAD) population, options for improved geographic sharing and status of potentially disenfranchised groups. They analyzed waiting list and posttransplant mortality rates of a contemporary cohort of patient groups at risk, in collaboration with the Scientific Registry of Transplant Recipients to develop a proposed multi-tiered allocation scheme. This proposal provides a framework for simulation modeling to project whether candidates would have better waitlist survival in the revised allocation system, and whether posttransplant survival would remain stable. The tiers are subject to change, based on further analysis by the Heart Subcommittee and will lead to the development of a more effective and equitable heart allocation system.
Subject(s)
Health Care Rationing , Heart Diseases/surgery , Heart Transplantation , Resource Allocation , Tissue and Organ Procurement , Adult , Directed Tissue Donation , Humans , United States , Waiting ListsABSTRACT
In this study, the influence exogenous electron shuttles on the growth and glucose fermentative metabolism of Clostridium sp. BC1 was investigated. Bicarbonate addition to mineral salts (MS) medium accelerated growth and glucose fermentation which shifted acidogenesis (acetic- and butyric-acids) towards solventogenesis (ethanol and butanol). Addition of ferrihydrite, anthraquinone disulfonate, and nicotinamide adenine dinucleotide in bicarbonate to growing culture showed no significant influence on fermentative metabolism. In contrast, methyl viologen (MV) enhanced ethanol- and butanol-production by 28- and 12-fold, respectively with concomitant decrease in hydrogen, acetic- and butyric-acids compared to MS medium. The results show that MV addition affects hydrogenase activity with a significant reduction in hydrogen production and a shift in the direction of electron flow towards enhanced production of ethanol and butanol.
Subject(s)
Butanols/metabolism , Clostridium/metabolism , Ethanol/metabolism , Fermentation/physiology , Glucose/metabolism , Anaerobiosis , Clostridium/growth & development , Electron Transport/physiology , Fermentation/drug effects , Hydrogenase/metabolism , Paraquat/pharmacology , Sodium Bicarbonate/pharmacologyABSTRACT
A number of research irradiations of (68)Zn was carried out at Brookhaven Linac Isotope Producer aiming to develop a practical approach to produce the radioisotope (67)Cu through the high energy (68)Zn(p,2p)(67)Cu reaction. Disks of enriched zinc were prepared by electrodeposition of (68)Zn on aluminum or titanium substrate and isolated in the aluminum capsule for irradition. Irradiations were carried out with 128, 105 and 92 MeV protons for at least 24h. After irradiation the disk was chemically processed to measure production yield and specific activity of (67)Cu and to reclaim the target material. The recovered (68)Zn was irradiated and processed again. The chemical procedure comprised BioRad cation exchange, Chelex-100 and anion exchange columns. Reduction of the oxidation degree of copper allowed for more efficient Cu/Co/Zn separation on the anion exchange column. No radionuclides other than copper isotopes were detected in the final product. The chemical yield of (67)Cu reached 92-95% under remote handling conditions in a hot box. Production yield of (67)Cu averaged 29.2 µCi/[µA-h×g (68)Zn] (1.08MBq/[µA-h×g (68)Zn]) in 24h irradiations. The best specific activity achieved was 18.6 mCi/µg (688.2 MBq/µg).
ABSTRACT
Laboratory batch and column experiments were conducted to investigate the role of microbial exudates, e.g., exopolymeric substance (EPS) and alginic acid, on microbial Cr(VI) reduction by two different Pseudomonas strains (P. putida P18 and P. aeuroginosa P16) as a method for treating subsurface environment contaminated with Cr(VI). Our results indicate that microbial exudates significantly enhanced microbial Cr(VI) reduction rates by forming less toxic and highly soluble organo-Cr(III) complexes despite the fact Cr(III) has a very low solubility under the experimental conditions studied (e.g., pH 7). The formation of soluble organo-Cr(III) complexes led to the protection of the cells and chromate reductases from inactivation. In systems with no organic ligands, soluble organo-Cr(III) end products were formed between Cr(III) and the EPS directly released by bacteria due to cell lysis. Our results also provide evidence that cell lysis played an important role in microbial Cr(VI) reduction by Pseudomonas bacteria due to the release of constitutive reductases that intracellularly and/or extracellularly catalyzed the reduction of Cr(VI) to Cr(III). The overall results highlight the need for incorporation of the release and formation of organo-Cr(III) complexes into reactive transport models to more accurately design and monitor in situ microbial remediation techniques for the treatment of subsurface systems contaminated with Cr(VI).
Subject(s)
Chromium/metabolism , Exudates and Transudates/metabolism , Pseudomonas/metabolism , Soil Pollutants/metabolism , Biodegradation, Environmental , Chromium/analysis , Soil Microbiology , Soil Pollutants/analysisABSTRACT
Chromium (III) binding by exopolymeric substances (EPS) isolated from Pseudomonas putida P18, Pseudomonas aeruginosa P16 and Pseudomonas stutzeri P40 strains were investigated by the determination of conditional stability constants and the concentration of functional groups using the ion-exchange experiments and potentiometric titrations. Spectroscopic (EXAFS) analysis was also used to obtain information on the nature of Cr(III) binding with EPS functional groups. The data from ion-exchange experiments and potentiometric titrations were evaluated using a non-electrostatic discrete ligand approach. The modeling results show that the acid/base properties of EPSs can be best characterized by invoking four different types of acid functional groups with arbitrarily assigned pK(a) values of 4, 6, 8 and 10. The analysis of ion-exchange data using the discrete ligand approach suggests that while the Cr binding by EPS from P. aeruginosa can be successfully described based on a reaction stoichiometry of 1:2 between Cr(III) and HL(2) monoprotic ligands, the accurate description of Cr binding by EPSs extracted from P. putida and P. stutzeri requires postulation of 1:1 Cr(III)-ligand complexes with HL(2) and HL(3) monoprotic ligands, respectively. These results indicate that the carboxyl and/or phosphoric acid sites contribute to Cr(III) binding by microbial EPS, as also confirmed by EXAFS analysis performed in the current study. Overall, this study highlights the need for incorporation of Cr-EPS interactions into transport and speciation models to more accurately assess microbial Cr(VI) reduction and chromium transport in subsurface systems, including microbial reactive treatment barriers.
Subject(s)
Chromium/metabolism , Polysaccharides, Bacterial/metabolism , Soil Pollutants/metabolism , Adsorption , Chromium/chemistry , Hydrogen-Ion Concentration , Kinetics , Models, Biological , Models, Chemical , Polysaccharides, Bacterial/chemistry , Soil/chemistry , Soil Pollutants/chemistry , X-Ray Absorption SpectroscopyABSTRACT
Phthalic acid, a ubiquitous organic ligand, formed soluble mono- and biligand complexes with a uranyl ion that was then reduced to a U(IV)-phthalate by a Clostridium species under anaerobic conditions. We confirmed the reduction of the hexavalent uranium to the tetravalent oxidation state by UV-vis absorption and X-ray absorption near edge structure spectroscopy. Sequential micro- and ultrafiltration of the solution revealed that the bioreduced uranium was present as a colloid with particles between 0.03 and 0.45 microm. Analysis with extended X-ray absorption fine structure revealed the association of the reduced uranium with the phthalic acid as a repeating biligand 1:2 U(IV):phthalic acid polymer. This is the first report of the formation of a U(IV) complexed to two phthalic acid molecules in the form of a polymeric colloid. Although it was proposed that the bioreduction and the precipitation of uranium might be an invaluable strategy to immobilize uranium in contaminated environments, our results suggest that the organic ligands present there might hinder the precipitation of the bioreduced uranium under anaerobic conditions and, thereby, enhance its environmental mobility as uranium organic complexes or colloids.
Subject(s)
Colloids/chemistry , Phthalic Acids/chemistry , Polymers/chemistry , Soil Pollutants, Radioactive , Uranium/chemistry , Water Pollutants, Radioactive , Biodegradation, Environmental , Oxidation-Reduction , Solubility , Time FactorsABSTRACT
Macroscopic and spectroscopic investigations (XAFS, XRF, and TRLIF) on Hanford contaminated vadose zone sediments from the U-tank farm showed that U(VI) exists as different surface phases as a function of depth below ground surface (bgs). Secondary precipitates of U(VI) silicate precipitates (boltwoodite and uranophane) were present dominantly in shallow-depth sediments (15-16 m bgs), while adsorbed U(VI) phases and polynuclear U(VI) surface precipitates were considered to dominate in intermediate-depth sediments (20-25 m bgs). Only natural uranium was observed in the deeper sediments (> 28 m bgs) with no signs of contact with tank wastes containing Hanford-derived U(VI). Across all depths, most of the U(VI) was preferentially associated with the silt and clay size fractions of sediments. Strong correlation between U(VI) and Ca was found in the shallow-depth sediments, especially for the precipitated U(VI) silicates. Because U(VI) silicate precipitates dominate in the shallow-depth sediments, the released U(VI) concentration by macroscopic (bi)carbonate leaching resulted from both desorption and dissolution processes. Having different U(VI) surface phases in the Hanford contaminated sediments indicates that the U(VI) release mechanism could be complicated and that detailed characterization of the sediments using several different methods would be needed to estimate U(VI) fate and transport correctly in the vadose zone.
Subject(s)
Environmental Monitoring , Geologic Sediments/chemistry , Uranium/chemistry , Radioactive Waste , Washington , Water Pollutants, Radioactive/chemistry , Water Pollution, Radioactive/prevention & controlABSTRACT
Frequency modulation atomic force microscopy (FM-AFM) is rapidly evolving as the technique of choice in the pursuit of high resolution imaging of biological samples in ambient environments. The enhanced stability afforded by this dynamic AFM mode combined with quantitative analysis enables the study of complex biological systems, at the nanoscale, in their native physiological environment. The operational bandwidth and accuracy of constant amplitude FM-AFM in low Q environments is heavily dependent on the cantilever dynamics and the performance of the demodulation and feedback loops employed to oscillate the cantilever at its resonant frequency with a constant amplitude. Often researchers use ad hoc feedback gains or instrument default values that can result in an inability to quantify experimental data. Poor choice of gains or exceeding the operational bandwidth can result in imaging artifacts and damage to the tip and/or sample. To alleviate this situation we present here a methodology to determine feedback gains for the amplitude and frequency loops that are specific to the cantilever and its environment, which can serve as a reasonable "first guess," thus making quantitative FM-AFM in low Q environments more accessible to the nonexpert. This technique is successfully demonstrated for the low Q systems of air (Q approximately 40) and water (Q approximately 1). In addition, we present FM-AFM images of MC3T3-E1 preosteoblast cells acquired using the gains calculated by this methodology demonstrating the effectiveness of this technique.
ABSTRACT
Phthalic acid, a ubiquitous organic compound found in soil, water, and in domestic and nuclear wastes can affect the mobility and bioavailability of metals and radionuclides. We examined the complexation of uranium with phthalic acid by potentiometric titration, electrospray ionization-mass spectroscopy (ESI-MS), and extended X-ray absorption fine structure (EXAFS) analysis. Potentiometric titration of a 1:1 U/phthalic acid indicated uranyl ion bonding with both carboxylate groups of phthalic acid; above pH 5 the uranyl ion underwent hydrolysis with one hydroxyl group coordinated to the inner-sphere of uranium. In the presence of excess phthalic acid, ESI-MS analysis revealed the formation of both 1:1 and 1:2 U/phthalic acid complexes. EXAFS studies confirmed the mononuclear biligand 1:2 U/phthalic acid complex as the predominant form. These results show that phthalates can form soluble stable complexes with uranium and may affect its mobility.
Subject(s)
Phthalic Acids/chemistry , Uranium/chemistry , Organometallic Compounds/chemical synthesis , Organometallic Compounds/chemistry , Potentiometry/methods , Solubility , Spectrometry, Mass, Electrospray Ionization/methods , Spectrometry, X-Ray Emission/methodsABSTRACT
An anaerobic, gram positive, spore-forming bacterium Clostridium sp., common in soils and wastes, capable of reduction of Fe(III) to Fe(II), Mn(IV) to Mn(II), Tc(VII) to Tc(IV), and U(VI) to U(IV), reduced Pu(IV) to Pu(III). Addition of 242Pu (IV)-nitrate to the bacterial growth medium at pH 6.4 resulted in the precipitation of Pu as amorphous Pu(OH)4 due to hydrolysis and polymerization reactions. The Pu (1 x 10(-5) M) had no effect upon growth of the bacterium as evidenced by glucose consumption; carbon dioxide and hydrogen production; a decrease in pH of the medium from 6.4 to 3.0 due to production of acetic and butyric acids from glucose fermentation; and a change in the Eh of the culture medium from +50 to -180 mV. Commensurate with bacterial growth, Pu was rapidly solubilized as evidenced by an increase in Pu concentration in solution which passed through a 0.03 microm filtration. Selective solvent extraction of the culture by thenoyltrifluoroacetone (TTA) indicated the presence of a reduced Pu species in the soluble fraction. X-ray absorption near edge spectroscopic (XANES) analysis of Pu in the culture sample at the Pu LIII absorption edge (18.054 keV) showed a shift of -3 eV compared to a Pu(IV) standard indicating reduction of Pu(IV) to Pu(III). These results suggestthat, although Pu generally exists as insoluble Pu(IV) in the environment, under appropriate conditions, anaerobic microbial activity could affect the long-term stability and mobility of Pu by its reductive dissolution.
Subject(s)
Anaerobiosis , Clostridium/metabolism , Plutonium/metabolism , Biotransformation , Oxidation-Reduction , Solubility , Spectrum Analysis/methodsABSTRACT
Angiotensin-converting enzyme inhibitors combined with higher doses of hydrochlorothiazide (HCT), that is, 25 mg daily, have been recognized as an effective form of antihypertensive therapy. To evaluate the coadministration of 20 mg ramipril with 25 mg HCT, we carried out a randomized, double-blind, controlled trial with two dose schedules of ramipril (20 mg q.d. and 10 mg b.i.d.) and HCT monotherapy arms as comparators in 354 patients with stage 2 hypertension. The clinic blood pressure (BP) was assessed using a semiautomatic digital device and 24-h BP was measured using ambulatory BP recordings at baseline and after 8 weeks of therapy. At baseline, the demographics and baseline BP values were similar in the four treatment groups (age: 51-53 years, 52-58% male, 64-68% non-black, clinic BP: 155-158/103-104 mm Hg). Ramipril-HCT induced significantly greater reductions in both the clinic and ambulatory BP than the HCT and ramipril monotherapy treatments (for example, additional reductions in ambulatory BP on ramipril-HCT ranged from -7.3/-5.2 to -10.3/-7.4 mm Hg compared to the monotherapies, all P<0.001). Reductions from baseline were still numerically greater for the clinic BPs derived from device measurements than those for the BP values derived from 24-h ambulatory BP measurements (changes in clinic diastolic BP ranged from -8.5 to -15.5 mm Hg across treatment groups, whereas changes in ambulatory diastolic BP were -4.7 to -12.0 mm Hg for the same groups). Thus, these data support the use of ambulatory BP monitoring even when automated BP devices are used for the assessment of clinical BP in trials that attempt to differentiate BP responses among active comparator groups. In conclusion, based on its efficacy and tolerability profile the combination of ramipril and HCT was shown to be effective therapy for the treatment of stage 2 hypertension.
Subject(s)
Angiotensin-Converting Enzyme Inhibitors/therapeutic use , Blood Pressure Determination/statistics & numerical data , Blood Pressure/drug effects , Diuretics/therapeutic use , Hydrochlorothiazide/therapeutic use , Hypertension/physiopathology , Ramipril/therapeutic use , Angiotensin-Converting Enzyme Inhibitors/administration & dosage , Blood Pressure/physiology , Diuretics/administration & dosage , Dose-Response Relationship, Drug , Double-Blind Method , Drug Therapy, Combination , Female , Follow-Up Studies , Humans , Hydrochlorothiazide/administration & dosage , Hypertension/drug therapy , Male , Middle Aged , Ramipril/administration & dosage , Treatment OutcomeABSTRACT
Inorganic polyphosphates (PolyP) are simple linear phosphate (PO(4)(3-)) polymers which are produced by a variety of microorganisms. One of their functions is to complex metals resulting in their precipitation. We investigated the interaction of phosphate and low-molecular-weight PolyP (1400-1900Da) with uranyl ion at various pHs. Potentiometric titration of uranyl ion in the presence of phosphate showed two sharp inflection points at pHs 4 and 8 due to uranium hydrolysis reaction and interaction with phosphate. Titration of uranyl ion and PolyP revealed a broad inflection point starting at pH 4 indicating that complexation of U-PolyP occurs over a wide range of pHs with no uranium hydrolysis. EXAFS analysis of the U-HPO(4) complex revealed that an insoluble uranyl phosphate species was formed below pH 6; at higher pH (> or = 8) uranium formed a precipitate consisting of hydroxophosphato species. In contrast, adding uranyl ion to PolyP resulted in formation of U-PolyP complex over the entire pH range studied. At low pH (< or = 6) an insoluble U-PolyP complex having a monodentate coordination of phosphate with uranium was observed. Above pH 6 however, a soluble bidentate complex with phosphate and uranium was predominant. These results show that the complexation and solubility of uranium with PO(4) and PolyP are dependent upon pH.
Subject(s)
Polyphosphates/chemistry , Uranyl Nitrate/chemistry , Chemical Precipitation , Hydrogen-Ion Concentration , Hydrolysis , Models, Molecular , Potentiometry , SolubilityABSTRACT
AIMS: The goal of this study was to determine whether nisin and lactoferrin would act synergistically to inhibit the growth of Listeria monocytogenes and Escherichia coli O157:H7. METHODS AND RESULTS: Lactoferrin and nisin separately or in combination were suspended in peptone yeast glucose broth and following inoculation with L. monocytogenes or E. coli O157:H7 growth inhibition of each pathogen was determined. At 1000 microg ml(-1) lactoferrin L. monocytogenes was effectively inhibited. However, E. coli O157:H7 initially was inhibited and then grew to cell density similar to the control. A combination of 500 microg ml(-1) of lactoferrin and 250 IU ml(-1) of nisin effectively inhibited the growth of E. coli O157:H7, whereas, 250 microg ml(-1) of lactoferrin and 10 IU ml(-1) of nisin were inhibitory to L. monocytogenes. CONCLUSIONS: The results suggest that lactoferrin and nisin act synergistically to inhibit the growth of L. monocytogenes and E. coli O157:H7. SIGNIFICANCE AND IMPACT OF THE STUDY: Natural preservatives that are active against gram-positive and gram-negative pathogens are desirable to the food industry and consumers. This study demonstrates that lactoferrin and nisin work synergistically reducing the levels required independently inhibiting growth of two major foodborne pathogens. Previous reported results indicated a low level of antimicrobial activity; however, this work was not performed in low divalent cation concentration media. It has been suggested that nondivalent cation-limiting medium such as trypticase soy broth (TSB), can reduce or completely eliminate the inhibitory activity. Further knowledge of these interactions can increase the understanding of the antimicrobial activity of lactoferrin. This should make the use of these compounds by industry more attractive.
Subject(s)
Anti-Bacterial Agents/pharmacology , Escherichia coli O157/drug effects , Lactoferrin/pharmacology , Listeria monocytogenes/drug effects , Nisin/pharmacology , Animals , Cattle , Drug SynergismABSTRACT
p18(Ink4c) functions as a dedicated inhibitor of cyclin-D-dependent kinases. Loss of Ink4c predisposes mice to tumor development and, in a dose-dependent manner, complements the tumor-promoting effects of various oncogenes. We have now addressed whether Ink4c loss impacts B-cell tumor development in the Emu-Myc transgenic mouse, a model of human Burkitt lymphoma. Loss of one or both alleles did not influence the onset of lymphoma in Emu-Myc transgenics, and did not appreciably affect Myc's proliferative or apoptotic responses in precancerous B cells. Nevertheless, Ink4c loss modulated the effects of Myc-induced transformation by decreasing the frequency of Arf loss, an ordinarily common event in Emu-Myc-induced lymphomas.
Subject(s)
Cyclin-Dependent Kinase Inhibitor p18/physiology , Lymphoma, B-Cell/genetics , Lymphoma, B-Cell/prevention & control , Proto-Oncogene Proteins c-myc/physiology , Animals , Apoptosis/genetics , Cell Proliferation , Cyclin-Dependent Kinase Inhibitor p16/genetics , Cyclin-Dependent Kinase Inhibitor p18/genetics , Disease Progression , Gene Expression Regulation, Neoplastic , Genes, Immunoglobulin Heavy Chain , Lymphoma, B-Cell/pathology , Mice , Mice, Inbred C57BL , Mice, Transgenic , Oncogene Proteins, Fusion/genetics , Oncogene Proteins, Fusion/physiology , Proto-Oncogene Proteins c-myc/geneticsABSTRACT
The stability constants and the associated thermodynamic parameters of formation of the binary and the ternary complexes of Am(3+), Cm(3+) and Eu(3+) were determined by a solvent extraction to measure the variation in the distribution coefficient with temperature (0-60 degrees C) for aqueous solutions of I = 6.60 m (NaClO(4)). The formation of ternary complexes is favored by both the enthalpy (exothermic) and the entropy (endothermic) values. (13) C NMR, TRLFS and EXAFS spectral data was used to study the coordination modes of the ternary complexes. In the formation of the complex M(EDTA)(Ox)(3-), the EDTA retained all its coordination sites with Ox binding via two carboxylates and with one water of hydration remaining attached to the M(3+). In the complex M(EDTA)(Ox)(2)(5-), one carboxylate, either from EDTA or Ox, is not bounded to M(3+) and there were no water of hydration attached to these cations.