Estimating the economic burden of osteoporotic fractures in a multinational study: a real-world data perspective.

Fracture-related costs vary by country. A standardized methodology and presentations were proposed to fairly assess the economic burden of osteoporotic fracture. Results indicated substantial costs of osteoporotic fractures for pharmacy, hospitalization, emergency care, and outpatient visits in women aged ≥ 50 years in Australia, Germany, South Korea, Spain, and the USA. PURPOSE: The objective of this multinational, retrospective matched cohort study was to use a standardized methodology across different healthcare systems to estimate the burden of osteoporotic fracture (OF) in women aged ≥ 50 years in Australia, Germany, South Korea, Spain, and the USA. METHODS: Within each country, healthcare resource utilization and direct costs of care were compared between patients with newly identified OF and a propensity score-matched cohort without OF during follow-up periods of up to 5 years. RESULTS: Across all five countries, the OF cohort had significantly higher rates and length of inpatient admissions compared with the non-OF cohort. In each country, the adjusted total costs of care ratio between OF and non-OF cohorts were significant. The adjusted cost ratios for pharmacy, inpatient care, emergency care, and outpatient visits were similarly higher in the OF cohort across countries. CONCLUSION: The current study demonstrates the substantial economic burden of OF across different countries when compared with matched non-OF patients. The findings would assist stakeholders and policymakers in developing appropriate health policies.

Participation in a randomised controlled feasibility study of a complex intervention for the management of the Respiratory Symptom Distress Cluster in lung cancer: patient, carer and research staff views.

This paper reports finding from a nested qualitative study designed to elicit the views and perceptions of those who participated in a randomised controlled feasibility trial testing a non-pharmacological intervention, Respiratory Distress Symptom Intervention (RDSI), for the management of the breathlessness-cough-fatigue symptom cluster in lung cancer. Semi-structured interviews were conducted with 11 lung cancer patients, three caregivers and seven researchers involved in recruitment, consent, RDSI training and delivery and participant follow-up. Thematic analysis identified key considerations including: the importance of informed consent emphasising commitment to completion of paperwork and raising awareness of potential sensitivities relating to content of questionnaires; ensuring screening for the presence of symptoms reflects the language used by patients; appreciation of the commitment required from participants to learn intervention techniques and embed them as part of everyday life; conduct of interviews with patients who decline to participate; and conduct of serial interviews with those receiving RDSI to further inform its routine implementation into clinical practice. This study will inform the development of a fully powered follow-on trial testing the hypothesis that RDSI plus usual care is superior to usual care alone in the effective management of this symptom cluster in lung cancer.

Flash photolysis-electron spin resonance studies of photosystem I. A fast reduction of component of P-700+.

A 300 mus decay component of ESR Signal I (P-700+) in chloroplasts is observed following a 10 mus actinic xenon flash. This transient is inhibited by treatments which block electron transfer from Photosystem II to Photosystem I (e.g. 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB), KCN and HgCl2). The fast transient reduction of P-700+ can be restored in the case of DCMU or DBMIB inhibition by addition of an electron donor couple (2,6-dichlorophenol indophenol (Cl2Ind)/ascorbate) which supplies electrons to cytochrome f. However, this donor couple is inefficient in restoring electron transport in chloroplasts which have been inhibited with the plastocyanin inactivators, KCN and HgCl2. Oxidation-reduction measurements reveal that the fast P-700+ reduction component reflects electron transfer from a component with Em = 375 +/- 10 mV (pH = 7.5). These data suggest the assignment of the 300-mus decay kinetics to electron transfer from cytochrome f (Fe2+) to P-700+, thus confirming the recent observations of Haehnel et al. (Z. Naturforsch. 26b, 1171-1174 (1971)).

A major site of bicarbonate effect in system II reaction. Evidence from ESR signal IIvf, fast fluorescence yield changes and delayed light emission.

In order to determine the major site of bicarbonate action in the electron transport complex of Photosystem II, the following experimental techniques were used: electron spin resonance measurements of Signal IIvf, measurements of chlorophyll a fluorescence yield rise and decay kinetics, and delayed light emission decay. From data obtained using these experimental techniques the following conclusions were made: (1) absence of bicarbonate causes a reversible inactivation of up to 40% of Photosystem II reaction center activity; (2) there is no significant effect of bicarbonate on electron flow from the charge accumulating S state to Z; (3) there is no significant effect of bicarbonate on electron flow from Z to P-680+; (4) electron flow from Q-- to the intersystem electron transport pool is inhibited by from 4- to 6-fold under bicarbonate depletion conditions.

Photosystem I charge separation in the absence of centers A and B. II. ESR spectral characterization of center 'X' and correlation with optical signal 'A2'.

The Photosystem I electron acceptor complex was characterized by optical flash photolysis and electron spin resonance (ESR) spectroscopy after treatment of a subchloroplast particle with lithium dodecyl sulfate (LDS). The following properties were observed after 60 s of incubation with 1% LDS followed by rapid freezing. (i) ESR centers A and B were not observed during or after illumination of the sample at 19 K, although the P-700+ radical at g = 2.0026 showed a large, reversible light-minus-dark difference signal. (ii) Center 'X', characterized by g factors of 2.08, 1.88 and 1.78, exhibited reversible photoreduction at 8 K in the absence of reduced centers A and B. (iii) The backreaction kinetics at 8 K between P-700, observed at g = 2.0026, and center X, observed at g = 1.78, was 0.30 s. (iv) The amplitudes of the reversible g = 2.0026 radical observed at 19 K and the 1.2 ms optical 698 nm transient observed at 298 K were diminished to the same extent when treated with 1% LDS at room temperature for periods of 1 and 45 min. We interpret the strict correlation between the properties and lifetimes of the optical P-700+ A2 reaction pair and the ESR P-700+ center X- reaction pair to indicate that signal A2 and center X represent the same iron-sulfur center in Photosystem I.

Redox study of electron donation to P-680 in Photosystem II.

Flash-induced absorption changes at 820 nm were studied as a function of redox potential in Tris-extracted Photosystem II oxygen-evolving particles and Triton subchloroplast fraction II particles. The rereduction kinetics of P-680+ in both preparations showed biphasic recovery phases with half-times of 42 and 625 microseconds at pH 4.5. The magnitude of the 42 microseconds phase of P-680+ rereduction was strongly dependent on the redox potential of the medium. This absorption transient, attributed to electron donation from D1 (the secondary electron donor in oxygen-inhibited chloroplasts), titrated as a single redox component with a midpoint potential of +240 +/- 35 mV. The experimentally determined midpoint potential was found to be independent of pH over the tested range 4.5-6.0. In contrast, the magnitude of the 625 microseconds phase of P-680+ rereduction was independent of redox potential between +350 and +100 mV. These results are interpreted in terms of a model in which an alternate electron donor with Em approximately equal to 240 mV, termed D0, serves as a rapid donor (t 1/2 less than or equal to 2 microseconds) to P-680+ in Tris-extracted and Triton-treated Photosystem-II preparations. According to this model, the slower electron donor, D1, is functional only when D0 becomes oxidized.

Electron-spin resonance studies of the bound iron-sulfur centers in Photosystem I. II. Correlation of P-700 triplet production with urea/ferricyanide inactivation of the iron-sulfur clusters.

Photosystem I charge separation in a subchloroplast particle isolated from spinach was investigated by electron spin resonance (ESR) spectroscopy following graduated inactivation of the bound iron-sulfur centers by urea-ferricyanide treatment. Previous work demonstrated a differential decrease in iron-sulfur centers A, B and X which indicated that center X serves as a branch point for parallel electron flow through centers A and B (Golbeck, J.H. and Warden, J.T. (1982) Biochim. Biophys. Acta 681, 77-84). We now show that during inactivation the disappearance of iron-sulfur centers A, B, and X correlates with the appearance of a spin-polarized triplet ESR signal with [D] = 279 X 10(-4) cm-1 and [E] = 39 X 10(-4) cm-1. The triplet resonances titrate with a midpoint potential of +380 +/- 10 mV. Illumination of the inactivated particles results in the generation of an asymmetric ESR signal with g = 2.0031 and delta Hpp = 1.0 mT. Deconvolution of the P-700+ contribution to this composite resonance reveals the spectrum of the putative primary acceptor species A0, which is characterized by g = 2.0033 +/- 0.0004 and delta Hpp = 1.0 +/- 0.2 mT. The data presented in this report do not substantiate the participation of the electron acceptor A1 in PS I electron transport, following destruction of the iron-sulfur cluster corresponding to center X. We suggest that A1 is closely associated with center X and that this component is decoupled from the electron-transport path upon destruction of center X. The inability to photoreduce A1 in reaction centers lacking a functional center X may result from alteration of the reaction center tertiary structure by the urea-ferricyanide treatment or from displacement of A1 from its binding site.

On the mechanism of linolenic acid inhibition in Photosystem II.

Recent studies in our laboratory have reexamined the interaction of the unsaturated fatty acid, linolenic acid, with Photosystem II and have documented two principal regions of inhibition: one associated with the donor complex (Signal 2f or D1) to the reaction center, and the other located on the reducing side between pheophytin and Qa (Golbeck, J.H. and Warden, J.T. (1984) Biochim. Biophys. Acta 767, 263-271). A further characterization of fatty acid inhibition of secondary electron transport in Photosystem II at room and cryogenic temperatures is presented in this paper. These studies demonstrate that linolenic acid, and related fatty acid analogs, eliminate the transient absorption increase at 320 nm, attributed to Qa-; abolish the production, either chemically or photochemically, of the ESR signal (Q-Fe) associated with the bound quinone acceptor, Qa-; and prevent the photooxidation of Signal 2(1t)(D1) at cryogenic temperature. Linolenic-acid-treated samples are characterized by a high initial fluorescence yield (Fi) equivalent to the maximum level of fluorescence (Fmax); however, the spin-polarized triplet, associated with the reaction-center electron donor, P-680, is observed only in inhibited samples that have been prereduced with sodium dithionite. These results suggest the presence of an additional acceptor intermediate between pheophytin and Qa. The donor-assisted photoaccumulation of pheophytin anion in Photosystem II particles, as monitored by the decline of fluorescence yield, is inhibited by linolenic acid. Redox titrations of the fluorescence yield in control and inhibited preparations demonstrate that the midpoint potential for the primary acceptor for Photosystem II is insensitive to the fatty acid (Em approximately -583 mV) and thus indicate that primary photochemistry is functional during linolenic-acid inhibition. These data are consistent with the hypothesis that unsaturated fatty acids inhibit secondary electron transport in Photosystem II via displacement of endogenous quinone from quinone-binding peptides.

Interaction of linolenic acid with bound quinone molecules in Photosystem II. Time-resolved optical and electron spin resonance studies.

Time-resolved spectroscopic techniques, including optical flash photolysis and electron spin resonance spectroscopy, have been utilized to monitor electron-transport activity in Photosystem II subchloroplast particles. These studies have indicated that in the presence of 100 microM linolenic acid (1) a high initial fluorescence yield (Fi) is observed upon steady-state illumination of the dark-adapted sample; (2) flash-induced absorption transients (t greater than 10 mus) in the region of 820 nm, attributed to P-680+, are first slowed, then abolished; and (3) electron spin resonance Signal IIs and Signal IIf (Z+) are not detectable. Upon reversal of linolenic acid inhibition by washing with bovine serum albumin, optical and electron spin resonance transients originating from the photooxidation of P-680 are restored. Similarly, the variable component of fluorescence is recovered with an accompanying restoration of Signal IIs and Signal IIf. The data indicate that linolenic acid affects two inhibition sites in Photosystem II: one located between pheophytin and QA on the reducing side, and the other between electron donor Z and P-680 on the oxidizing side. Since both sites are associated with bound quinone molecules, we suggest that linolenic acid interacts at the level of quinone binding proteins in Photosystem II.

Phenylglyoxal modification of the Photosystem II reaction center.

Time-resolved spectroscopic techniques, including optical flash photolysis and electron spin resonance (ESR), have been used in conjunction with fluorescence-induction and dye-reduction assays to monitor electron transport in Photosystem II (PS II) subchloroplast particles incubated with the covalent modifier, phenylglyoxal. Phenylglyoxal-modified digitonin (D-10) particles from spinach are characterized by a high initial fluorescence yield (Fi) and an abolition of the variable component of fluorescence (Fv); an inhibition of PS-II-mediated reduction of dichlorophenol indophenol (DPIP) by sym-diphenylcarbazide; an abolition of flash-induced absorption transients (t1/2 greater than 2 microseconds) at 820 nm attributed to the primary electron donor, P-680+; the inhibition of photoreduction of the acceptor Qa; and the elimination of the ESR Signal 2s and Signal 2f. These observations suggest the critical participation of specific arginine residues on both the oxidizing and reducing sides of Photosystem II and also implicate phenylglyoxal as a quinone-binding site inhibitor (Golbeck, J.H. and Warden, J.T. (1984) Biochim. Biophys. Acta 767, 263-271).

A flash photolysis ESR study of photosystem II signal IIvf, the physiological donor to P-680+.

In flash-illuminated, oxygen-evolving spinach chloroplasts and green algae, a free radical transient has been observed with spectral parameters similar to those of Signal II (g approximately 2.0045, deltaHpp approximately 19G). However, in contrast with ESR Signal II, the transient radical does not readily saturate even at microwave power levels of 200 mW. This species is formed most efficiently with "red" illumination (lambda less than 680 nm) and occurs stoichiometrically in a 1:1 ratio with P-700+. The Photosystem II transient is formed in less than 100 mus and decays via first-order kinetics with a halftime of 400-900 mus. Additionally, the t1/2 for radical decay is temperature independent between 20 and 4 degrees C; however, below 4 degrees C the transient signal exhibits Arrhenius behavior with an activation energy of approx. 10 kcal-mol-1. Inhibition of electron transport through Photosystem II by o-phenanthroline, 3-(3,4-dichlorophenyl)-1,1-dimethylurea or reduced 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone suppresses the formation of the light-induced transient. At low concentrations (0.2 mM), 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone partially inhibits the free radical formation, however, the decay kinetics are unaltered. High concentrations of 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (1-5 mM) restore both the transient signal and electron flow through Photosystem II. These findings suggest that this "quinoidal" type ESR transient functions as the physiological donor to the oxidized reaction center chlorophyll, P-680+.

Investigation of the ammonium chloride and ammonium acetate inhibition of oxygen evolution by Photosystem II.

Using EPR and EXAFS spectroscopies we show that high concentrations of ammonium cations at alkaline pH are required for (1) inhibition of oxygen evolution: (2) an alteration of the EPR properties of the oxygen evolving complex: (3) the ability to detect YZ; and (4) the slow reduction of the Mn complex leading to the appearance of EPR detectable Mn2+. The inhibition of S state cycling, slowing of YZ reduction, appearance of Mn2+ and the yield of a Hpp < 10 mT S3 type EPR signal are decreased by calcium addition. This indicates that these effects were probably associated with calcium depletion arising from the high concentration of ammonium cation. The ammonia-induced changes to the S2 multiline EPR signal are not affected by calcium addition. The appearance of Mn2+ is shown to be reversible on illumination, suggesting that the Mn reduced from the native state is located at or near the native site. Simulations of the interaction which give rise to the S3 EPR signal are also presented and discussed. These indicate that lineshape differences occur through small changes in the exchange component of the interaction between the manganese complex and organic radical, probably through minor structural changes between the variously treated samples.

Is phylloquinone an obligate electron carrier in photosystem I?

Comparative quantitative analysis of phylloquinone content and photochemically competent P-700 has been performed on photosystem I particles subjected to photolysis with ultraviolet irradiation. Nonirradiated control particles exhibit a phylloquinone/P-700 stoichiometry of 1.9 +/- 0.2. Photolysis of the photosystem I particles induces a progressive depletion of phylloquinone, however, photochemistry as assayed at room temperature by the photooxidation of P-700 is unaffected. These data are not consistent with the assignment of phylloquinone as a functional intermediate at room temperature between P-700 and the iron-sulfur clusters, center A and center B.

Simultaneous peptide and oligonucleotide formation in mixtures of amino acid, nucleoside triphosphate, imidazole, and magnesium ion.

Simultaneous peptide and oligonucleotide formation was observed in reaction mixtures of amino acid, nucleoside triphosphate, imidazole, and MgCl2. At 70 degrees C in solutions that were evaporated to dryness the formation of peptide for phe and pro was greatest with CTP relative to ATP, GTP, and UTP. Lysine exhibited a preference for GTP and glycine for UTP. At ambient temperature insolution at pH 7.8, CTP was preferred by glycine, but at pH 8.7 UTP was preferred. The glycine nucleotide phosphoramidates were also detected and characterized in reactions at 40 degrees C. The glycine-reaction preference for CTP at pH 7.8 and UTP at 8.7 suggested that the basicity of the nucleoside triphosphate was involved in increasing the peptide yield. CTP near neutrality is the most basic nucleoside triphosphate and the basic anionic form UTP could facilitate peptide formation at pH 8.7. These data, together with information on the complexing of poly(C) by GTP, led to the experimentally approchable hypothesis that GTP, by forming a basic triplex between the cytosine residues adjacent to the peptidyl adenosine and aminoacyl adenosine at the termini of two proto-tRNAs, would promote peptide bond synthesis between the aminoacyl residue and peptidyl residue.

International Arctic Seas Assessment Project.

The International Atomic Energy Agency responded to the news that the former Soviet Union had dumped radioactive wastes in the shallow waters of the Arctic Seas, by launching the International Arctic Seas Assessment Project in 1993. The project had two objectives: to assess the risks to human health and to the environment associated with the radioactive wastes dumped in the Kara and Barents Seas; and to examine possible remedial actions related to the dumped wastes and to advise on whether they are necessary and justified. The current radiological situation in the Arctic waters was examined to assess whether there is any evidence for releases from the dumped waste. Potential future releases from the dumped wastes were predicted, concentrating on the high-level waste objects containing the major part of the radionuclide inventory of the wastes. Environmental transport of released radionuclides was modelled and the associated radiological impact on humans and the biota was assessed. The feasibility, costs and benefits of possible remedial measures applied to a selected high-level waste object were examined. Releases from identified dumped objects were found to be small and localised to the immediate vicinity of the dumping sites. Projected future annual doses to members of the public in typical local population groups were very small, less than 1 microSv--corresponding to a trivial risk. Projected future doses to a hypothetical group of military personnel patrolling the foreshore of the fjords in which wastes have been dumped were higher, up to 4 mSv/year, which still is of the same order as the average annual natural background dose. Moreover, since any of the proposed remedial actions were estimated to cost several million US$ to implement, remediation was not considered justified on the basis of potentially removing a collective dose of 10 man Sv. Doses calculated to marine fauna were insignificant, orders of magnitude below those at which detrimental effects on fauna populations might be expected to occur. Remediation was thus concluded not to be warranted on radiological grounds.