The severity of airways obstruction as a determinant of treatment response in COPD

Guidelines recommend that patients with COPD are stratified arbitrarily by baseline severity (FEV₁) to decide when to initiate combination treatment with a long-acting β₂-agonist and an inhaled corticosteroid. Assessment of baseline FEV₁ as a continuous variable may provide a more reliable prediction of treatment effects. Patients from a 1-year, parallel-group, randomized controlled trial comparing 50 μg salmeterol (Sal), 500 μg fluticasone propionate (FP), the combination (Sal/FP) and placebo, (bid), were categorized post hoc into FEV₁ <50% and FEV₁ ≥50% predicted subgroups (n=949/513 respectively). Treatment effects on clinical outcomes – lung function, exacerbations, health status, diary card symptoms, and adverse events – were investigated. Treatment responses based on a pre-specified analysis explored treatment differences by severity as a continuous variable. Lung function improved with active treatment irrespective of FEV₁; Sal/FP had greatest effect. This improvement appeared additive in milder disease; synergistic in severe disease. Active therapy significantly reduced exacerbation rate in patients with FEV₁ <50% predicted, not in milder disease. Health status and breathlessness improved with Sal/FP irrespective of baseline FEV₁; adverse events were similar across subgroups. The spirometric response to Sal/FP varied with baseline FEV₁, and clinical benefits were not restricted to patients with severe disease. These data have implications for COPD management decisions, suggesting that arbitrary stratifications of baseline severity are not necessarily indicative of treatment efficacy and that the benefits of assessing baseline severity as a continuous variable should be assessed in future trials.     

Effect of add-on therapy of tiotropium in COPD treated with theophylline

Background

Although combination therapy with bronchodilators is recommended for chronic obstructive pulmonary disease (COPD), there is insufficient evidence for the efficacy of some combinations of long-acting bronchodilators.

Objective

We investigated the effects of a combination therapy with tiotropium and theophylline in COPD patients.

Methods

In a 12-week, open-labeled, parallel-group randomized study, pulmonary functions and dyspnea scores were compared between the combination and theophylline alone therapy at baseline, and 4 and 8 weeks after randomization in COPD.

Results

Sixty-one COPD patients completed the trial (31 combination therapy, 30 theophylline alone; mean age 70 years; 58 males; mean dyspnea score 2.0 and forced expiratory volume in one second (FEV₁) 1.5 L [62.5% predicted]). FEV₁ in the combination group, but not in the theophylline alone, was significantly increased at 4 (1.56 ± 0.13 L, p < 0.001) and 8 weeks (1.60 ± 0.13 L, p < 0.001) from the baseline (1.40 ± 0.12 L). In the combination group, but not the theophylline alone group, the dyspnea score was significantly improved after 4 (p < 0.01) and 8 weeks (p < 0.05) compared with baseline. In 17 patients who did not receive theophylline at screening, treatment with 4 or 8 weeks of theophylline alone did not improve dyspnea score or FEV₁.

Conclusion

Addition of tiotropium therapy to theophylline treatment can improve dyspnea and pulmonary function in COPD. Although this study did not assess whether there was any benefit of adding theophylline to patients treated with tiotropium, tiotropium can be a useful addition in COPD already treated with theophylline.     

Trapping the ATP binding state leads to a detailed understanding of the F1-ATPase mechanism

The rotary motor enzyme F_oF₁-ATP synthase uses the proton-motive force across a membrane to synthesize ATP from ADP and P_i (H₂PO₄⁻) under cellular conditions that favor the hydrolysis reaction by a factor of 2 × 10⁵. This remarkable ability to drive a reaction away from equilibrium by harnessing an external force differentiates it from an ordinary enzyme, which increases the rate of reaction without shifting the equilibrium. Hydrolysis takes place in the neighborhood of one conformation of the catalytic moiety F₁-ATPase, whose structure is known from crystallography. By use of molecular dynamics simulations we trap a second structure, which is rotated by 40° from the catalytic dwell conformation and represents the state associated with ATP binding, in accord with single-molecule experiments. Using the two structures, we show why P_i is not released immediately after ATP hydrolysis, but only after a subsequent 120° rotation, in agreement with experiment. A concerted conformational change of the α₃β₃ crown is shown to induce the 40° rotation of the γ-subunit only when the β_E subunit is empty, whereas with P_i bound, β_E serves as a latch to prevent the rotation of γ. The present results provide a rationalization of how F₁-ATPase achieves the coupling between the small changes in the active site of β_DP and the 40° rotation of γ.The molecular motor F_oF₁-ATP synthase is composed of two domains: a transmembrane portion (F_o), the rotation of which is induced by a proton gradient, and a globular catalytic moiety (F₁) that synthesizes and hydrolyzes ATP. The primary function of the proton-motive force acting on F_oF₁-ATP synthase is to provide the torque required to rotate the γ-subunit in the direction for ATP synthesis (1, 2). The catalytic moiety, F₁-ATPase, has an α₃β₃ “crown” composed of three α- and three β-subunits arranged in alternation around the γ-subunit, which has a globular base and an extended coiled-coil portion (3) (Fig. 1A). F₁-ATPase by itself binds ATP and hydrolyzes it to induce rotation of the γ-subunit (in the opposite direction from that for synthesis) on the millisecond time scale under optimum conditions (4, 5). All of the α- and β-subunits bind nucleotides, but only the three β-subunits are catalytically active. The original crystal structure (3) of F₁-ATPase from bovine heart mitochondria (MF₁) led to the identification of three conformations of the β-subunit: β_E (empty), β_TP (ATP analog bound), and β_DP (ADP bound); Fig. 1A. In the known structures of F₁-ATPase, which apparently are near the “catalytic dwell” state, the state in which catalysis occurs (6, 7), the β_E subunit conformation is partly to fully open and is very different from those of the β_TP and β_DP subunits, which are closed and very similar to each other (SI Appendix, SI1).Open in a separate windowFig. 1.(A) F₁-ATPase. The three β-subunits and the γ-subunit are shown (α-subunits are not shown for clarity): β_E (yellow), β_DP (orange), β_TP (gold), and γ (purple). To define the β_DP subunit conformation we use the angle between helix B (βT163-A176) and helix C (βT190-G204). The two helices are highlighted: helix B (blue) and helix C (gray); the B^C angle is depicted as a red angle. The β_DPH6 helix, whose orientation was reported to undergo a 20° change during the 40° substep γ-rotation, is highlighted as red. During the forced rotation simulations with an external torque, the force acts on the C_α atom of MF₁:γM25 (shown as a red sphere). The direction of the force is determined as the cross-product of the radial vector of γM25:C_α and the rotational axis (green). (B) Proposed 360° rotation cycle of F₁-ATPase showing the subunit conformations, as well as the binding–release of ligands and the hydrolysis of ATP. Starting from the binding of an ATP* to the β_E subunit in the ATP waiting state (0°), rotation of the γ-stalk by 200° (80°, 40°, 80°) leads to the transition of β_E (γ = 0°) via β_TP (γ = 80°) to β_DP (γ = 200°), the catalytic dwell state where hydrolysis of ATP* takes place. The hydrolysis product P_i* in the β_DP subunit is not released at this catalytic dwell (200°). Instead, the other hydrolysis product ADP* is released first after a 40° rotation [β_DP (200°) → β_HO (240°)]. Then, β_HO is transformed to β_E and P_i* is released after an additional 80° rotation to another catalytic dwell state (320°); the latter is shown in brackets outside the main cycle (see below). Finally, the release of P_i* from β_E leads to a 40° rotation that completes the 360° cycle (21, 41). The other subunits are going through corresponding cycles offset by 120° (β_DP) and 240° (β_TP), respectively. Here, the prime symbol when it appears on the β_DP and β_E conformations indicates that the conformation of corresponding subunits change slightly in or near the specified reaction steps. The γ-subunit is shown as a yellow oval, and its rotation during the hydrolysis cycle is indicated by a red arrow. The reaction steps occurring in or near the catalytic dwell and corresponding changes of ligands in each β-subunit are also shown in the 320° catalytic dwell: The first state (Left in the 320° catalytic dwell) has a bound ATP in β_DP′, and is thus referred to as a prehydrolysis state (the state before the hydrolysis of ATP during the catalytic dwell). The second state (Middle) represents the state after ATP hydrolysis (posthydrolysis state), and the third state (Right) presents the state after the release of P_i bound in β_E′ (postrelease state).     

Budesonide�Cformoterol (inhalation powder) in the treatment of COPD

The budesonide–formoterol dry powder inhaler (Symbicort^® Turbuhaler^® 160/4.5–640/18 μg/day) contains the long-acting β₂-adrenoreceptor agonist formoterol and the inhaled corticosteroid budesonide. Two large, 12-month trials examined the effect of budesonide–formoterol 160/4.5 μg twice daily in COPD patients who met these criteria. The studies were identical, except one in which the patients had received oral prednisolone 30 mg/day and had inhaled formoterol 4.5 μg twice daily for 2 weeks before randomization. In terms of the FEV₁, budesonide–formoterol produced an effect greater than that of both budesonide alone and formoterol alone reported in previous studies. The combination was generally more effective than either of the components in terms of peak expiratory flow, symptoms, and exacerbations. These advantages of the combination over those of either budesonide alone or formoterol alone were quite consistent. Improving lung function and decreasing symptoms significantly, budesonide–formoterol combination therapy provides significant clinical improvements in COPD, despite the limited reversibility of impaired lung function in the disease.     

Benefits of short inspiratory muscle training on exercise capacity, dyspnea, and inspiratory fraction in COPD patients

Static lung hyperinflation has important clinical consequences in patients with chronic obstructive pulmonary disease (COPD). Given that most of these patients have respiratory and peripheral muscle weakness, dyspnea and functional exercise capacity may improve as a result of inspiratory muscle training (IMT). The present study is designed to investigate the benefits of a short outpatient program of IMT on inspiratory muscle performance, exercise capacity, perception of dyspnea, and the inspiratory fraction (IF). Thirty patients (24 males, 6 females) with significant COPD (forced expiratory volume in one second [FEV₁] = 46.21% ± 6.7% predicted, FEV₁ = 33.6% ± 8.04% predicted) were recruited for this study and had 3 months of IMT (30 minutes/day for 6 days/week) in an outpatient clinic. Following IMT, there was a statistically significant increase in inspiratory muscle performance (an increase of the maximal inspiratory pressure from 59% ± 19.1% to 79% ± 21.85% predicted; p = 0.0342), a decrease in dyspnea (from 5.8 ± 0.78 to 1.9 ± 0.57; p = 0.0001), an increase in the distance walked during the 6 minute walk test, from 245 ± 52.37 m to 302 ± 41.30 m, and finally an increase in the IF (the new prognostic factor in COPD) from 27.6 ± 9.7% to 31.4% ± 9.8%. The present study concludes that in patients with significant COPD, IMT results in improvement in performance, exercise capacity, sensation of dyspnea, and moreover an improvement in the IF prognostic factor.     

A dose-ranging study of tiotropium delivered via Respimat? Soft MistTM Inhaler or HandiHaler? in COPD patients

This was a multicenter, randomized, double-blind within device, parallel-group, dose-ranging study. COPD patients (n = 202; 86% male; mean age: 61 years) were randomized to receive tiotropium 1.25 μg, 2.5 μg, 5 μg, 10 μg, or 20 μg Respimat^® SMI (a novel, propellant-free device); tiotropium 18 μg HandiHaler^®; placebo Respimat^®; or placebo HandiHaler^® for 3 weeks. The primary endpoint was trough FEV₁ on Day 21. Other assessments included FVC, PEFR, rescue medication use, safety, and pharmacokinetics. In general, all active treatments improved the primary and secondary endpoints on Day 21 (steady state) compared with placebo. Tiotropium 5 μg Respimat^®, 20 μg Respimat^®, and tiotropium 18 μg HandiHaler^® were statistically significantly higher than placebo for the primary endpoint (mean change in trough FEV₁ was 150 mL (both Respimat^® doses) versus 20 mL (placebo Respimat^®); p < 0.05; and 230 mL (HandiHaler^®) versus −90 mL (placebo HandiHaler^®); p ≤ 0.001). The urinary excretion (up to 2 hours post-dose) of tiotropium 5–10 μg Respimat^® was comparable with tiotropium 18 μg HandiHaler^®; the overall incidence of adverse events was comparable across treatment groups. Tiotropium 5 and 10 μg Respimat^® improve lung function in COPD patients and appear to be comparable with tiotropium 18 μg HandiHaler^®.     

Effect of Bilateral Lung Volume Reduction Surgery on FEV1 Decline in Severe Emphysema

Study Objective. To examine whether lung volume reduction surgery (LVRS) alters the anticipated natural rates of decline in FEV₁. Design. Retrospective analysis of spirometry results (188 studies) in patients before and after bilateral LVRS. Setting. Large, urban, academic medical center. Patients. 25 patients with severe emphysema (mean (SD) age 60 ± 8 yrs; FEV₁ 0.74 ± 0.29 L, 29% predicted). Interventions. Bilateral LVRS performed via median sternotomy, with areas targeted for resection based on preoperative evaluation using high-resolution computed tomography, quantitative perfusion scans, and intraoperative inspection of the lungs. Linear regression analysis was performed on each patient using all serial postbronchodilator FEV₁ values from before and after LVRS. Results. Lung function data were available between 2–1001 days prior to LVRS and 71–1169 days after LVRS. Comparison of single pre- and post-LVRS FEV₁ results confirmed a significant post-operative (3 month) improvement in lung function. The calculated rate of decline in FEV₁ prior to LVRS was 202 ± 205 mL/yr. Following LVRS, the rate of decline in FEV₁ was unchanged at 178 ± 150 mL/yr (p = 0.64). Conclusions. In patients with severe emphysema, bilateral LVRS does not appear to significantly alter the rate of FEV₁ decline.     

Effect of tiotropium on health-related quality of life as a primary efficacy endpoint in COPD

Clinical manifestations of chronic obstructive pulmonary disease (COPD), including airflow limitation, dyspnea, and activity limitation, ultimately lead to impaired health-related quality of life (HRQoL). This 9-month, randomized, double-blind, multicenter study compared the effect of once-daily tiotropium 18 μg and placebo on HRQoL, spirometric parameters, and exacerbations in 554 patients with moderate-to-severe COPD. HRQoL was assessed using the St. George’s Respiratory Questionnaire (SGRQ) and the new 8-item Visual Simplified Respiratory Questionnaire (VSRQ), which is currently being validated. The primary efficacy endpoint was the proportion of patients achieving a reduction of at least 4 units in the SGRQ total score at study end (Month 9). Mean ± SD baseline SGRQ total score was 47.4 ± 18.1. Significantly more tiotropium-treated patients achieved a reduction of at least 4 units in the SGRQ score vs placebo at study end (59.1% vs 48.2%, respectively; p = 0.029). Tiotropium significantly improved spirometric parameters (forced expiratory volume in 1 second [FEV₁]: 0.11 ± 0.02 L vs 0.01 ± 0.02 L; between-group difference: 0.10 ± 0.03 L, p = 0.0001) and reduced exacerbations vs placebo. Maintenance treatment with tiotropium provided significant and clinically relevant improvements in HRQoL, as measured by the SGRQ.     

Human platelets inhibit liver fibrosis in severe combined immunodeficiency mice

AIM:To investigate the role of human platelets in liver fibrosis.METHODS:Severe combined immunodeficiency(SCID)mice were administered CCl4and either phosphate-buffered saline(PBS group)or human platelet transfusions(hPLT group).Concentrations of hepatocyte growth factor(HGF),matrix metallopeptidases(MMP)-9,and transforming growth factor-β(TGF-β)in the liver tissue were compared between the PBS and the hPLT groups by enzyme-linked immunosorbent assay(ELISA)and Western blotting.The effects of a human platelet transfusion on liver fibrosis included the fibrotic area,hydroxyproline content,and-smooth muscle actin(α-SMA)expression,which were evaluated by picrosirius red staining,ELISA,and immunohistochemical staining using an anti-mouse-SMA antibody,respectively.Phosphorylations of mesenchymal-epithelial transition factor(Met)and SMAD3,downstream signals of HGF and TGF-β,were compared between the two groups by Western blotting and were quantified using densitometry.Hepatocyte apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling.Furthermore,the accumulation of human platelets in the liver 2 h after platelet transfusion was compared between normal and fibrotic livers by immunohistochemical staining using an anti-human CD41 antibody.RESULTS:The fibrotic area and hydroxyproline content in the liver were both significantly lower in the hPLT group when compared to the PBS group(fibrotic area,1.7%±0.6%vs 2.5%±0.6%,P=0.03;hydroxyproline content,121±26 ng/g liver vs 156±47 ng/g liver,P=0.04).There was less α-smooth muscle actin staining in the hPLT group than in the PBS group(0.5%±0.1%vs 0.8%±0.3%,P=0.02).Hepatic expression levels of mouse HGF and MMP-9were significantly higher in the hPLT group than in the PBS group(HGF,109±13 ng/g liver vs 88±22 ng/g liver,P=0.03;MMP-9,113%±7%/GAPDH vs 92%±11%/GAPDH,P=0.04).In contrast,the concentration of mouse TGF-β in the liver tissue was significantly lower in the hPLT group than in the PBS group(22±5ng/g liver vs 39±6 ng/g liver,P=0.     

Comparison of PPIs and H2-receptor antagonists plus prokinetics for dysmotility-like dyspepsia

AIM: To compare efficacy of proton pump inhibitors (PPIs) with H₂-receptor antagonists (H₂RAs) plus prokinetics (Proks) for dysmotility-like symptoms in functional dyspepsia (FD).METHODS: Subjects were randomized to receive open-label treatment with either rabeprazole 10 mg od (n = 57) or famotidine 10 mg bid plus mosapride 5 mg tid (n = 57) for 4 wk. The primary efficacy endpoint was change (%) from baseline in total dysmotility-like dyspepsia symptom score. The secondary efficacy endpoint was patient satisfaction with treatment.RESULTS: The improvement in dysmotility-like dyspepsia symptom score on day 28 was significantly greater in the rabeprazole group (22.5% ± 29.2% of baseline) than the famotidine + mosapride group (53.2% ± 58.6% of baseline, P < 0.0001). The superior benefit of rabeprazole treatment after 28 d was consistent regardless of Helicobacter pylori status. Significantly more subjects in the rabeprazole group were satisfied or very satisfied with treatment on day 28 than in the famotidine + mosapride group (87.7% vs 59.6%, P = 0.0012). Rabeprazole therapy was the only significant predictor of treatment response (P < 0.0001), defined as a total symptom score improvement ≥ 50%.CONCLUSION: PPI monotherapy improves dysmotility-like symptoms significantly better than H₂RAs plus Proks, and should be the treatment of first choice for Japanese FD.     

COPD heterogeneity: Gender differences in the multidimensional BODE index

Background:

The BODE index was recently validated as a multidimensional tool for the evaluation of patients with COPD. The influence of gender on the BODE index has not been studied.

Hypothesis:

The contribution of each component of the disease to the BODE index may differ according to gender.

Methods:

We evaluated age, forced expiratory volume in one second (FEV₁), Modified Medical Research Council (MMRC) score, 6-min walk distance (6MWD), and body mass index (BMI) in 52 men and 52 women with COPD and the same BODE index. We compared the studied parameters between men and women and then performed a multiple regression analysis by gender.

Results:

We found statistically significant differences between men and women in all parameters: FEV₁ % (55 ± 17 vs 63 ± 18, p < 0.001), MMRC [1 (0–2) vs 1 (1–2) p = 0.03], BMI [28 (26–30) vs 25 (22–30), p = 0.05], and 6MWD [546 (451–592) vs 462 (419–520), p = 0.001]. Multiple regression analysis revealed that each component of the BODE index had different weight (β standardized coefficient) in men and women respectively: FEV₁% (0.74 vs 0.62), MMRC (0.31 vs 0.48), BMI (−0.09 vs −0.17), and 6MWD (0.13 vs 0.10).

Conclusions:

The contribution of each component to the BODE index differs by gender in subjects with similar BODE scores. Long term longitudinal studies will help determine the significance of our findings.     

Effect of interferon-γ and tumor necrosis factor-α on hepatitis B virus following lamivudine treatment

AIM: To evaluate anti-hepatitis B virus (HBV) activity and cytotoxicity of interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) following lamivudine treatment of HepG2.2.15 cells.METHODS: HepG2.2.15 cells were treated with 2 μmol/L lamivudine for 16 d (lamivudine group), cultured for 10 d, followed by 5 ng/mL TNF-α and 1000 U/mL IFN-γ for 6 d (cytokine group), or treated with 2 μmol/L lamivudine for 10 d followed by 5 ng/mL TNF-α and 1000 U/mL IFN-γ for 6 d (sequential group), or cultured without additions for 16 d (control group). Intracellular DNA was extracted from 3 × 10⁵ HepG2.2.15 cells from each group. The extracted DNA was further purified with mung bean nuclease to remove HBV relaxed circular DNA that may have remained. Both HBV covalently closed circular DNA (cccDNA) and HBV DNA were examined with real-time polymerase chain reaction. The titers of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) were quantified with enzyme-linked immunosorbent assay. Cell viability was measured with the cell counting kit-8 assay.RESULTS: Compared to lamivudine alone (22.63% ± 0.12%), both sequential (51.50% ± 0.17%, P = 0.034) and cytokine treatment (49.66% ± 0.06%, P = 0.041) showed a stronger inhibition of HBV cccDNA; the difference between the sequential and cytokine groups was not statistically significant (51.50% ± 0.17% vs 49.66% ± 0.06%, P = 0.88). The sequential group showed less inhibition of HBV DNA replication than the lamivudine group (67.47% ± 0.02% vs 82.48% ± 0.05%, P = 0.014); the difference between the sequential and cytokine groups was not statistically significant (67.47% ± 0.02% vs 57.45% ± 0.07%, P = 0.071). The levels of HBsAg and HBeAg were significantly decreased in the sequential treatment group compared to the other groups [HBsAg: 3.48 ± 0.04 (control), 3.09 ± 0.08 (lamivudine), 2.55 ± 0.13 (cytokine), 2.32 ± 0.08 (sequential), P = 0.042 for each between-group comparison; HBeAg: 3.48 ± 0.01 (control), 3.08 ± 0.08 (lamivudine), 2.57 ± 0.15 (cytokine), 2.34 ± 0.12 (sequential), P = 0.048 for each between-group comparison]. Cell viability in the cytokine group was reduced to 58.03% ± 8.03% compared with control cells (58.03% ± 8.03% vs 100%, P = 0.000). Lamivudine pretreatment significantly reduced IFN-γ + TNF-α-mediated toxicity of HepG2.2.15 cells [85.82% ± 5.43% (sequential) vs 58.03% ± 8.03% (cytokine), P = 0.002].CONCLUSION: Sequential treatment overcame the lower ability of lamivudine alone to inhibit cccDNA and precluded the aggressive cytotoxicity involving IFN-γ and TNF-α by decreasing the viral load.     

Systemic inflammation after inspiratory loading in chronic obstructive pulmonary disease

Objective

Patients with chronic obstructive pulmonary disease (COPD) present systemic inflammation. Strenuous resistive breathing induces systemic inflammation in healthy subjects. We hypothesized that the increased respiratory load that characterizes COPD can contribute to systemic inflammation in these patients.

Patients and methods

To test this hypothesis, we compared leukocyte numbers and levels of circulating cytokines (tumor necrosis factor alpha [TNFα], interleukin-1β [IL-1β], IL-6, IL-8, and IL-10), before and 1 hour after maximal incremental inspiratory loading in 13 patients with stable COPD (forced expiratory volume in one second [FEV₁] 29 ± 2.5% ref) and in 8 healthy sedentary subjects (FEV₁ 98 ± 5% ref).

Results

We found that: (1) at baseline, patients with COPD showed higher leukocyte counts and IL-8 levels than controls (p < 0.01); and, (2) one hour after maximal inspiratory loading these values were unchanged, except for IL-10, which increased in controls (p < 0.05) but not in patients with COPD.

Conclusions

This study confirms the presence of systemic inflammation in COPD, shows that maximal inspiratory loading does not increase the levels of pro-inflammatory cytokines (IL-1β, IL-8) in COPD patients or controls, but suggests that the former may be unable to mount an appropriate systemic anti-inflammatory response to exercise.     

A Simple and Efficient Method for Preparing High-Purity α-CaSO4·0.5H2O Whiskers with Phosphogypsum

A simple and efficient approach for the high-purity CaSO₄·2H₂O (DH) whiskers and α-CaSO₄·0.5H₂O (α-HH) whiskers derived from such phosphogypsum (PG) was proposed. The impact of different experimental parameters on supersaturated dissolution–recrystallization and preparation processes of α-CaSO₄·0.5H₂O was elaborated. At 3.5 mol/L HCl concentration, the dissolution temperature and time were 90 °C and 20 min, respectively. After eight cycles and 5–8 times cycles, total crystallization amount of CaSO₄·2H₂O was 21.75 and 9.97 g/100 mL, respectively, from supersaturated HCl solution. The number of cycles affected the shape and amount of the crystal. Higher HCl concentration facilitated CaSO₄·2H₂O dissolution and created a much higher supersaturation, which acted as a larger driving force for phase transformation of CaSO₄·2H₂O to α-CaSO₄·0.5H₂O. The HCl solution system’s optimum experimental conditions for HH whiskers preparation involved acid leaching of CaSO₄·2H₂O sample, with HCl concentration 6.0 mol/L, reaction temperature 80 °C, and reaction time 30 min–60 min. Under the third cycle conditions, α-CaSO₄·0.5H₂O whiskers were uniform in size, clear, and distinct in edges and angles. The length range of α-CaSO₄·0.5H₂O whiskers was from 106 μm to 231 μm and diameter range from 0.43 μm to 1.35 μm, while the longest diameter ratio was 231. Purity of α-CaSO₄·0.5H₂O whiskers was approximately 100%, where whiteness reached 98.6%. The reuse of the solution enables the process to discharge no waste liquid. It provides a new reference direction for green production technology of phosphogypsum.     

Structural reorganization of the interleukin-7 signaling complex

We report here an unliganded receptor structure in the common gamma-chain (γ_c) family of receptors and cytokines. The crystal structure of the unliganded form of the interleukin-7 alpha receptor (IL-7Rα) extracellular domain (ECD) at 2.15 Å resolution reveals a homodimer forming an “X” geometry looking down onto the cell surface with the C termini of the two chains separated by 110 Å and the dimer interface comprising residues critical for IL-7 binding. Further biophysical studies indicate a weak association of the IL-7Rα ECDs but a stronger association between the γ_c/IL-7Rα ECDs, similar to previous studies of the full-length receptors on CD4⁺ T cells. Based on these and previous results, we propose a molecular mechanism detailing the progression from the inactive IL-7Rα homodimer and IL-7Rα–γ_c heterodimer to the active IL-7–IL-7Rα–γ_c ternary complex whereby the two receptors undergo at least a 90° rotation away from the cell surface, moving the C termini of IL-7Rα and γ_c from a distance of 110 Å to less than 30 Å at the cell surface. This molecular mechanism can be used to explain recently discovered IL-7– and γ_c-independent gain-of-function mutations in IL-7Rα from B- and T-cell acute lymphoblastic leukemia patients. The mechanism may also be applicable to other γ_c receptors that form inactive homodimers and heterodimers independent of their cytokines.     

Graph fission in an evolving voter model

We consider a simplified model of a social network in which individuals have one of two opinions (called 0 and 1) and their opinions and the network connections coevolve. Edges are picked at random. If the two connected individuals hold different opinions then, with probability 1 - α, one imitates the opinion of the other; otherwise (i.e., with probability α), the link between them is broken and one of them makes a new connection to an individual chosen at random (i) from those with the same opinion or (ii) from the network as a whole. The evolution of the system stops when there are no longer any discordant edges connecting individuals with different opinions. Letting ρ be the fraction of voters holding the minority opinion after the evolution stops, we are interested in how ρ depends on α and the initial fraction u of voters with opinion 1. In case (i), there is a critical value α_c which does not depend on u, with ρ ≈ u for α > α_c and ρ ≈ 0 for α < α_c. In case (ii), the transition point α_c(u) depends on the initial density u. For α > α_c(u), ρ ≈ u, but for α < α_c(u), we have ρ(α,u) = ρ(α,1/2). Using simulations and approximate calculations, we explain why these two nearly identical models have such dramatically different phase transitions.     

Vitamin K1 supplementation to improve the stability of anticoagulation therapy with vitamin K antagonists: a dose-finding study

Background

Poor anticoagulant stability in patients using vitamin K antagonists is a risk factor for both bleeding and thrombosis. In previous studies supplementation with low dose vitamin K₁ was shown to improve the stability of anticoagulant control. We set up a study to confirm earlier reports and to determine the optimal daily dose of vitamin K₁ in preparation of a large study with clinical endpoints.

Design and Methods

Four hundred patients from two anticoagulation clinics starting with vitamin K antagonists, independently of a possible history of instable anticoagulation, were randomized to receive either placebo or 100, 150 or 200 μg of vitamin K₁ together with their treatment with vitamin K antagonists. The treatment was administered for 6 to 12 months. Anticoagulation stability, expressed as the percentage of time that the International Normalized Ratio was within the therapeutic range, was compared between the groups.

Results

After adjustment for age, sex, vitamin K antagonist used, anticoagulation clinic and interacting drugs as confounding factors the difference in percentage of time with the International Normalized Ratio within the therapeutic range between the placebo group and the vitamin K₁ groups was 2.1% (95% CI: −3.2% – 7.4%) for the group taking 100 μg, 2.7% (95% CI: −2.3% –7.6%) for the group taking 150 μg and 0.9% (95% CI: −4.5% – 6.3%) for the group taking 200 μg vitamin K₁ group, in favor of the vitamin K₁ groups. The patients from both the 100 μg group and the 150 μg group had a 2-fold higher chance of reaching at least 85% of time with the International Normalized Ratio within the therapeutic range. There were no differences in thromboembolic or hemorrhagic complications between the groups.

Conclusions

In patients starting vitamin K antagonists, supplementation with low dose vitamin K₁ resulted in an improvement of time that anticoagulation was within the therapeutic range. Differences between doses were, however, small and the improvement is unlikely to be of clinical relevance. For future studies we recommend selecting only patients with instable anticoagulant control. (This study was registered at www.isrctn.org as ISRCTN37109430)     

Effectiveness of Saccharomyces boulardii in a rat model of colitis

AIM: To investigate the effects of Saccharomyces boulardii (S. boulardii) in an experimental rat model of trinitrobenzene sulfonic acid (TNBS)-induced colitis.METHODS: Thirty-two Wistar albino female rats were categorized into five groups. On the first day of the study, 50 mg TNBS was administered via a rectal catheter in order to induce colitis in all rats, except those in the control group. For 14 d, the rats were fed a standard diet, without the administration of any additional supplements to either the control or TNBS groups, in addition to 1 mg/kg per day S. boulardii to the S. boulardii group, 1 mg/kg per day methyl prednisolone (MP) to the MP group. The animals in the S. boulardii + MP group were coadministered these doses of S. boulardii and MP. During the study, weight loss, stool consistency, and the presence of obvious blood in the stool were evaluated, and the disease activity index (DAI) for colitis was recorded. The intestines were examined and colitis was macro- and microscopically scored. The serum and tissue levels of tumor necrosis factor-α (TNF-α) and nitric oxide (NO) were determined, and fungemia was evaluated in the blood samples.RESULTS: The mean DAI scores for the MP and S. boulardii + MP groups was significantly lower than the TNBS group (3.69 ± 0.61 vs 4.46 ± 0.34, P = 0.018 and 3.77 ± 0.73 vs 4.46 ± 0.34, P = 0.025, respectively). While no significant differences between the TNBS and the S. boulardii or MP groups could be determined in terms of serum NO levels, the level of serum NO in the S. boulardii + MP group was significantly higher than in the TNBS and S. boulardii groups (8.12 ± 4.25 μmol/L vs 3.18 ± 1.19 μmol/L, P = 0.013; 8.12 ± 4.25 μmol/L vs 3.47 ± 1.66 μmol/L, P = 0.012, respectively). The tissue NO levels in the S. boulardii, MP and S. boulardii + MP groups were significantly lower than the TNBS group (16.62 ± 2.27 μmol/L vs 29.72 ± 6.10 μmol/L, P = 0.002; 14.66 ± 5.18 μmol/L vs 29.72 ± 6.10 μmol/L, P = 0.003; 11.95 ± 2.34 μmol/L vs 29.72 ± 6.10 μmol/L, P = 0.002, respectively). The tissue NO levels in the S. boulardii, MP and S. boulardii + MP groups were similar. The mean serum and tissue TNF-α levels were determined to be 12.97 ± 18.90 pg/mL and 21.75 ± 15.04 pg/mL in the control group, 18.25 ± 15.44 pg/mL and 25.27 ± 11.95 pg/mL in the TNBS group, 20.59 ± 16.15 pg/mL and 24.39 ± 13.06 pg/mL in the S. boulardii group, 9.05 ± 5.13 pg/mL and 24.46 ± 10.85 pg/mL in the MP group, and 13.95 ± 10.17 pg/mL and 24.26 ± 10.37 pg/mL in the S. boulardii + MP group. Significant differences in terms of the levels of serum and tissue TNF-α and the macroscopic and microscopic scores were not found between the groups. S. boulardii fungemia was not observed in any of the rats. However, Candida fungemia was detected in one rat (14%) in the TNBS group, two rats (28%) in the S. boulardii group, three rats (50%) in the MP group, and three rats (42%) in S. boulardii + MP group.CONCLUSION: S. boulardii does not demonstrate considerable effects on the DAI, pathological scores, or cytokine levels but does decrease the tissue NO levels.