Effects of arginase inhibition on myocardial Ca2+ and contractile responses

Nitric oxide (NO) is thought to increase cardiac contractility by increasing cytosolic Ca²⁺ concentration ([Ca²⁺ ]_cyt ) during excitation. Alternatively, NO could increase the sensitivity of the contractile response to [Ca²⁺ ]_cyt (Ca²⁺ sensitivity). Arginase regulates NO production by competing with NO synthase (NOS), and thus, arginase inhibition should increase cardiac contractility by increasing NO production. We hypothesized that arginase inhibition increases cardiac contractility by increasing both [Ca²⁺ ]_cyt and Ca²⁺ sensitivity. [Ca²⁺ ]_cyt and contractile (sarcomere length [SL] shortening) responses to electrical stimulation were measured simultaneously in isolated rat cardiomyocytes using an IonOptix system. In the same cardiomyocytes, measurements were obtained at baseline, following 3-min exposure to an arginase inhibitor (S-[2-boronoethyl]-l-cysteine; BEC) and following 3-min exposure to BEC plus a NOS inhibitor (N^G -nitro-l-arginine-methyl ester; l-NAME). These responses were compared to time-matched control cardiomyocytes that were untreated. Compared to baseline, BEC increased the amplitude and the total amount of evoked [Ca²⁺ ]_cyt , and the extent and velocity of SL shortening in cardiomyocytes, whereas addition of l-NAME mitigated these effects. The [Ca²⁺ ]_cyt at 50% contraction and relaxation were not different across treatment groups indicating no effect of BEC on Ca²⁺ sensitivity. The [Ca²⁺ ]_cyt and SL shortening responses in time-matched controls did not vary with time. Arginase inhibition by BEC significantly increased the amplitude and the total amount of evoked [Ca²⁺ ]_cyt , and the extent and velocity of SL shortening in cardiomyocytes, but did not affect Ca²⁺ sensitivity. These effects of BEC were mitigated by l-NAME. Together, these results indicate an effect of NO on [Ca²⁺ ]_cyt responses that then increase the contractile response of cardiomyocytes.

Conformational control of two-dimensional gold nanoparticle arrays in a confined geometry within a vesicular wall

The two-dimensional (2D) assembly of gold nanoparticles (AuNPs) in a confined geometry is a rare phenomenon that has not been experimentally verified for complex systems. In this study, this process was investigated in detail using two types of block copolymers with hydrophobic and hydrophilic blocks and a series of AuNPs of three different sizes protected by hydrophobic ligands. In aqueous solutions, the selected block copolymers self-assembled into vesicular nanostructures with a hydrophobic domain in the wall, which functions as a confined geometrical space for hydrophobic AuNPs (i.e., it exerts a confinement effect and restricts the movement of AuNPs). Small-angle X-ray scattering studies revealed that AuNPs of different sizes assembled differently in the same confined geometry of the vesicular wall. In addition, optimal conditions for the formation of a regular NP array in the hydrophobic domain were determined. The AuNPs successfully self-assembled into a regular 2D lattice structure, forming a shell around the vesicle, when their size matched the thickness of the hydrophobic domain of the vesicular nanostructure. This study provides guidelines for the fabrication of nanoparticle arrays with controlled structures, which could enhance the functionality of materials and their physical properties.

Self-Assembly of 2D Gold Nanoparticle Superlattice in a Polymer Vesicle Layer Driven by Hydrophobic Interaction

Self-assembly of gold nanoparticles (AuNPs) into highly ordered superstructures provides a promising route toward fabricating materials with new functionalities or enhanced physical properties. Although self-assembly of AuNPs has garnered significant research attention recently, a highly ordered superlattice of AuNPs under a low concentration in a confined geometry formed by nonfunctionalized materials has not been reported. Herein, we investigate the self-assembly of a 2D AuNPs superlattice in a polymer vesicle layer using hydrophobic interactions, which exhibits centered rectangular lattice symmetry. To create the highly ordered AuNPs superlattice, the P(EG_x-b-iPGE_y) block copolymers that form the thickness of the hydrophobic vesicle layer comparable to the size of the AuNP are used as a template to control the AuNP degree of freedom. To the best of our knowledge, this study provides the first demonstration of a centered rectangular structure formation of AuNPs at the vesicle layer in 2D confined geometry.

Association of Intereye Visual-Sensitivity Asymmetry With Progression of Primary Open-Angle Glaucoma

Purpose

To investigate the relationship between intereye visual field defect (VFD) asymmetry and subsequent VF progression in primary open-angle glaucoma (POAG).

Methods

Moderate-stage patients with POAG (226 eyes of 113 patients) with a single hemifield defect were followed for 8.7 years. Participants were categorized into three groups by initial VF pattern: (1) unilateral VFD, (2) bilateral VFD within same hemifield (superior–superior, inferior–inferior), (3) bilateral VFD within opposite hemifield (superior–inferior). The mean deviation (MD) difference between the intereye was defined as the intereye MD asymmetry index (iMAI). Intereye visual-sensitivity difference within the same hemifield was calculated as the intereye hemifield visual-sensitivity asymmetry index. Functional progression was detected by Glaucoma Progression Analysis. The overall rate of MD change and the association between new indices were evaluated by linear regression. A Kaplan-Meier survival analysis was performed and the factors associated with glaucoma progression were evaluated by Cox proportional hazard modeling.

Results

Unilateral VFD eyes and bilateral VFD eyes within opposite VF hemifield showed significant progression and faster rate of MD change compared with bilateral VFD eyes within same VF hemifield (71.1% vs. 45.9% vs. 21.1% [P = 0.001]; –1.27 dB/y vs. −0.64 dB/y vs. −0.32 dB/y [P = 0.001]). Unilateral VFD eyes showed the fastest time to VF progression compared with other groups (P = 0.002). A faster rate of MD change was associated with greater intereye MD asymmetry index (P = 0.001) and greater intereye hemifield visual-sensitivity asymmetric index (P = 0.031), which were significant risk factors for glaucoma progression (all P < 0.001).

Conclusions

Among POAG eyes with comparable hemifield VFDs, eyes without a corresponding hemifield defect in the fellow eye showed faster rates of progression compared with those with a corresponding hemifield defect.

Molecular Weight-Dependent, Flexible Phase Behaviors of Amphiphilic Block Copolymer/Additive Complexes in Aqueous Solution

Pluronic amphiphilic block copolymers, well known to have a phase behavior can be controlled by external conditions, have a wide range of potential for applications such as nanotemplates or nanobuilding blocks. However, the phase behaviors of Pluronic block copolymer/additive complexes with highly ordered phases have not been fully investigated. Here, we report the unusual molecular weight-dependent self-assembly of Pluronic block copolymer/additive complexes. Depending on the temperature and additive, Pluronic P65 block copolymer with a lower molecular weight showed the closed loop-like (CLL) phase behavior with the disorder-order-disorder-order phase transition in aqueous solution, whereas Pluronic P105 and P85 block copolymers with higher molecular weights underwent highly ordered continuous phase transitions with face centered cubic (FCC), hexagonal, and lamellar phases. It is expected that the specific phase behavior of the block copolymer/additive complex can be applied in optical devices such as nanotemplates or optical sensors for a highly ordered superlattice. Furthermore, this study provides a new route to control the phase behavior of the block copolymers without a complicated process.

Normal-tension Glaucoma Management: A Survey of Glaucoma Sub-specialists in Korea

PURPOSE

To investigate the current management patterns of glaucoma subspecialists with regard to normal-tension glaucoma (NTG) in Korea and to determine the effect of the two largest NTG trials on their clinical practice.

METHODS

A questionnaire survey was sent to glaucoma subspecialist members of the Korean Glaucoma Society. The questionnaire concerned regular practice with respect to NTG and the extent to which it has been influenced by the Collaborative Normal-tension Glaucoma Study and the Low-pressure Glaucoma Treatment Study (LoGTS).

RESULTS

A total of 134 glaucoma subspecialists completed the survey, with a response rate of 56%. The survey reported that 88% and 78% of glaucoma subspecialists were familiar with the Collaborative Normal-tension Glaucoma Study and the LoGTS, respectively. With respect to mild or moderate NTG, most of the respondents (87%-91%) tended to treat their patients immediately without waiting for structural or functional progression. Among the respondents, 47 indicated that the LoGTS results-according to which, 20% of the respondents tended to use brimonidine more often-affected their management. The first-choice topical drugs for NTG were prostaglandin analogues (76%), brimonidine (9%), beta-blockers (8%), and topical carbonic anhydrase inhibitor (6%).

CONCLUSIONS

Regarding mild-to-moderate NTG, Korean glaucoma subspecialists tended to initiate treatment without waiting for further progression. The impact of the LoGTS on NTG management was not dominant in clinical practice in Korea. Prostaglandin analogs are the most frequently selected first-choice drugs for the management of NTG in Korea.

Interdigitation Zone Change According to Glaucoma-Stage Advancement

Purpose

To compare the macular interdigitation zone (IZ) of normal eyes with eyes showing different normal-tension glaucoma (NTG) stages.

Methods

Forty-two normal eyes (age, 56 ± 5.4 years), 45 pre-perimetric eyes (age, 59 ± 6.9 years), 51 mild-to-moderate glaucoma eyes (age, 58 ± 7.2 years; mean deviation [MD], –5.5 ± 3.0 dB), and 50 severe glaucoma eyes (age, 59 ± 6.9 years; MD, –15.1 ± 5.4 dB) were enrolled. All of the subjects underwent high-resolution spectral-domain optical coherence tomography (SD-OCT) to obtain 19 horizontal and 19 vertical macular B-scans 9 mm in length. The en face image of the scan area was divided into 589 rectangular boxes (side length of 375 µm). The IZ locations were marked on the corresponding image boxes. The IZ area was then quantified according to the number of boxes showing IZs among the 589 total boxes.

Results

The IZ area in the severe glaucoma eyes was significantly smaller than in the mild-to-moderate glaucoma eyes (28.99 ± 7.88 mm² vs. 40.79 ± 7.46 mm²; P < 0.001), was smaller in the mild-to-moderate glaucoma eyes than in the pre-perimetric glaucoma eyes (40.79 ± 7.46 mm² vs. 49.92 ± 8.10 mm²; P < 0.001), and was smaller still in the pre-perimetric glaucoma eyes than in the normal eyes (49.92 ± 8.10 mm² vs. 56.85 ± 7.94 mm²; P < 0.001). In the 146 NTG eyes, a statistically significant correlation was found between IZ area and MD (r = 0.64; P < 0.001).

Conclusions

SD-OCT revealed a reduction in IZ area in NTG eyes, and the extent of the reduction was positively associated with glaucoma severity. These findings suggest, though tentatively, that changes in the outer retinal layer can occur in the course of glaucoma progression.

Explaining the Rationale of Deep Learning Glaucoma Decisions with Adversarial Examples

PURPOSE

To illustrate what is inside the so-called black box of deep learning models (DLMs) so that clinicians can have greater confidence in the conclusions of artificial intelligence by evaluating adversarial explanation on its ability to explain the rationale of DLM decisions for glaucoma and glaucoma-related findings. Adversarial explanation generates adversarial examples (AEs), or images that have been changed to gain or lose pathologic characteristic-specific traits, to explain the DLM's rationale.

DESIGN

Evaluation of explanation methods for DLMs.

PARTICIPANTS

Health screening participants (n = 1653) at the Seoul National University Hospital Health Promotion Center, Seoul, Republic of Korea.

METHODS

We trained DLMs for referable glaucoma (RG), increased cup-to-disc ratio (ICDR), disc rim narrowing (DRN), and retinal nerve fiber layer defect (RNFLD) using 6430 retinal fundus images. Surveys consisting of explanations using AE and gradient-weighted class activation mapping (GradCAM), a conventional heatmap-based explanation method, were generated for 400 pathologic and healthy patient eyes. For each method, board-trained glaucoma specialists rated location explainability, the ability to pinpoint decision-relevant areas in the image, and rationale explainability, the ability to inform the user on the model's reasoning for the decision based on pathologic features. Scores were compared by paired Wilcoxon signed-rank test.

MAIN OUTCOME MEASURES

Area under the receiver operating characteristic curve (AUC), sensitivities, and specificities of DLMs; visualization of clinical pathologic changes of AEs; and survey scores for locational and rationale explainability.

RESULTS

The AUCs were 0.90, 0.99, 0.95, and 0.79 and sensitivities were 0.79, 1.00, 0.82, and 0.55 at 0.90 specificity for RG, ICDR, DRN, and RNFLD DLMs, respectively. Generated AEs showed valid clinical feature changes, and survey results for location explainability were 3.94 ± 1.33 and 2.55 ± 1.24 using AEs and GradCAMs, respectively, of a possible maximum score of 5 points. The scores for rationale explainability were 3.97 ± 1.31 and 2.10 ± 1.25 for AEs and GradCAM, respectively. Adversarial example provided significantly better explainability than GradCAM.

CONCLUSIONS

Adversarial explanation increased the explainability over GradCAM, a conventional heatmap-based explanation method. Adversarial explanation may help medical professionals understand more clearly the rationale of DLMs when using them for clinical decisions.

[Meta-analysis of laparoscopic versus open surgery for palliative resection of the primary tumor in stage IV colorectal cancer]

Objective: To systematically evaluate the safety and efficacy of laparoscopic versus open surgery for palliative resection of the primary tumor in stage IV colorectal cancer. Methods: The databases of CNKI, Wanfang, VIP, PubMed, EMBASE and Cochrane Library were searched to retrieve randomized controlled trials (RCT) or clinical controlled trials (CCT) comparing laparoscopic surgery with open surgery for palliative resection of the primary tumor in stage IV colorectal cancer published from January 1991 to May 2019. Chinese search terms included "colorectum/colon/rectum" , "cancer/malignant tumor" , "laparoscopy" , "metastasis" , " IV" ; English search terms included "laparoscop*" , "colo*" , "rect*" , "cancer/tumor/carcinoma/neoplasm" , " IV" , "metasta*" . Inclusion criteria: (1) RCT or CCT, with or without allocation concealment or blinding; (2) patients with stage IV colorectal cancer that was diagnosed preoperatively and would receive resection of the primary tumor; (3) the primary tumor that was palliatively resected by laparoscopic or open procedure. Exclusion criteria: (1) no valid data available in the literature; (2) single study sample size ≤20; (3) subjects with colorectal benign disease; (4) metastatic resection or lymph node dissection was performed intraoperatively in an attempt to perform radical surgery; (5) duplicate publication of the literature. Two researchers independently evaluated the quality of the included studies. In case of disagreement, the evaluation was performed by discussion or a third researcher was invited to participate. The data were extracted from the included studies, and the Cochrane Collaboration RevMan 5.1.0 version software was used for this meta-analysis. Results: Four CCTs with a total of 864 patients were included in this study, including 216 patients in the laparoscopic group and 648 patients in the open group. Compared with the open group, except for longer operation time (WMD=37.60, 95% CI: 26.11 to 49.08, P<0.05), laparoscopic group had less intraoperative blood loss (WMD=-74.89, 95% CI: -144.78 to -5.00, P<0.05), earlier first flatus and food intake after surgery (WMD=-1.00, 95% CI: -1.12 to -0.87, P<0.05; WMD=-1.61, 95%CI: -2.16 to -1.06, P<0.05), shorter hospital stay (WMD=-2.01, 95% CI: -2.21 to -1.80, P<0.05) and lower morbidity of postoperative complication (OR=0.52, 95% CI: 0.35 to 0.77, P<0.05). However, no significant differences were found in time to start postoperative chemotherapy, postoperative chemotherapy rate, and mortality (P > all 0.05). Conclusion: Laparoscopic surgery for palliative resection of the primary tumor is safe and feasible to enhance recovery after surgery by promoting postoperative bowel function recovery, shortening hospital stay and reducing postoperative complication in stage IV colorectal cancer.

Morphological characteristics of parapapillary atrophy and subsequent visual field progression in primary open-angle glaucoma

BACKGROUND/AIMS

To investigate the associations between the morphological characteristics of beta-zone parapapillary atrophy (β-zone PPA) and subsequent visual field (VF) progression in eyes with primary open-angle glaucoma (POAG).

METHODS

One hundred and twenty-one POAG eyes with β-zone PPA along with 48 normal eyes with β-zone PPA were included. β-zone PPA area was calculated based on the PPA pixel area/optic-disc pixel area ratio and the optical coherence tomography (OCT)-measured disc area. β-zone PPA margin irregularity was quantified as a function of both area (A) and perimeter (P, calculated as 1/(4πA/P²)). VF progression was defined using standard automated perimetry's guided progression analysis software.

RESULTS

Of the 121 POAG eyes, 49 (40.5%) showed VF progression during the 10.1±1.9 years of follow-up. The baseline β-zone PPA area was similar among the three groups (Progressors, Non-progressors and Controls, p=0.995). However, the β-zone PPA irregularity index was significantly higher in the Progressors (p<0.001). The cumulative probability of VF progression was greater in the higher PPA irregularity index group (p<0.001, log-rank test). A Cox proportional hazards model showed the significant influences of optic disc haemorrhage (HR: 2.661, p=0.034) and higher baseline PPA irregularity index (HR: 1.455, p=0.007) on subsequent progression.

CONCLUSIONS

In POAG eyes, baseline β-zone PPA margin regularity was significantly associated with subsequent VF progression. Irregular margin of β-zone PPA might be the mark of vulnerability in the parapapillary area to further glaucomatous damage.

Ten Years and Beyond Longitudinal Change of ß-Zone Parapapillary Atrophy: Comparison of Primary Open-Angle Glaucoma with Normal Eyes

PURPOSE

To investigate the difference in longitudinal change of ß-zone parapapillary atrophy (PPA) between eyes with primary open-angle glaucoma (POAG) and normal eyes.

DESIGN

Longitudinal, observation study.

PARTICIPANTS

A total of 153 eyes with POAG and 105 normal eyes.

METHODS

Participants were followed for 10 years or more, with disc photography performed every year. The topographic parameters of ß-zone PPA (area, maximal radial extent, angular extent around disc) were measured. The factors associated with the enlargement of ß-zone PPA parameters were assessed by odds ratio (OR) using multivariable logistic regression.

MAIN OUTCOME MEASURES

Enlargement of ß-zone PPA parameters and associated factors.

RESULTS

Over the course of the average 11.6±1.3-year follow-up period, enlargement of β-zone PPA was detected in 66.7% of POAG eyes and in 26.7% of normal eyes. Increment of all PPA parameters was significantly more common in cases of POAG than in normal eyes (all P < 0.001). The spatial distribution of maximal radial extent at baseline and final examination was significantly different between the 2 groups: POAG eyes; inferotemporal versus normal eyes; temporal (chi-square = 26.549, P < 0.001, chi-square = 19.320, P = 0.004, respectively). The widening of radial extent was significantly associated with older age (OR, 1.036; P = 0.010) and the presence of glaucoma (OR, 2.599; P = 0.002). The increment of angular extent was associated with the presence of glaucoma (OR, 12.167; P = 0.017) and optic disc hemorrhage (OR, 3.266; P = 0.019).

CONCLUSIONS

The pattern of ß-zone PPA change differed between POAG and normal eyes during a follow-up of 10 years or more. The enlargement of PPA occurred more frequently in POAG than in normal eyes. The widening of radial extent was associated with older age and glaucoma, whereas the increment of angular extent was associated with glaucomatous damage.

The vasculature in HFpEF vs HFrEF: differences in contractile protein expression produce distinct phenotypes

Both heart failure with reduced (HFrEF) and preserved (HFpEF) ejection fraction are associated with abnormalities of the vasculature, including a resting vasoconstriction and a decrease in sensitivity to nitric oxide (NO) mediated vasodilation. Vascular tone is controlled by the expression and activation of both smooth muscle (SM) and nonmuscle (NM) myosin, and NO mediated vasodilation is regulated by the expression of the leucine zipper positive (LZ+) isoform of the myosin targeting subunit (MYPT1) of myosin light chain phosphatase (MLCP). This study was designed to determine the expression of these contractile proteins in humans with HFrEF and HFpEF vs normal controls. We isolated tertiary mesenteric vessels from remnant biospecimens of patients undergoing partial or total colectomy at Mayo Clinic Rochester from August 2017 to December 2018, and examined the expression of MYPT1 and the LZ + MYPT1 isoform with immunoblots, while 2D SDS-PAGE was used to resolve the phosphorylated and nonphosphorylated regulatory light chains of NM and SM myosin. Our data show that NM myosin expression, as a percentage of total myosin, was 12 ± 3% (controls, n = 6), 7 ± 5% (HFpEF, n = 4) and 37 ± 18% (HFrEF, n = 5, p < 0.05). Total MYPT1 expression was significantly reduced (p < 0.05) in both HFpEF (70 ± 11%) and HFrEF (48 ± 6%); and in HFrEF, LZ + MYPT1 was also depressed (62 ± 19%, <0.05). These results demonstrate that HFrEF and HFpEF are distinct vascular entities, and the changes in protein expression contribute to the vascular abnormalities associated with these diseases. Further in HFpEF, the decrease in MYPT1 would explain why pharmacologic therapies that are designed to activate the NO/cGMP/PKG signaling pathway do not produce a clinical benefit.

Identification of a novel RIG-I isoform and its truncating variant in Japanese eel, Anguilla japonica

Retinoic acid-inducible gene-I (RIG-I) is a cytoplasmic viral RNA sensor that triggers the production of type I interferons (IFNs) and proinflammatory cytokines during viral infection. RIG-I gene has been identified previously in Japanese eel, Anguilla japonica. In the present study, we have characterized a novel isoform of RIG-I (designated as AjRIG-Ib) and its truncated variant (AjRIG-Ibv). The AjRIG-Ib encodes 940 amino acids (aa) consisting of two N-terminal caspase activation and recruitment domains (CARDs), a DEX(D/H) box RNA helicase domain, and a C-terminal regulatory domain (CTD). The AjRIG-Ibv encodes a protein of 843 aa, that shares similar structural organization with AjRIG-Ib, but lacking CTD. The gene expression analyses showed that AjRIG-Ib and AjRIG-Ibv were detectable in all tissues/organs examined, and AjRIG-Ib was the predominant form. The mRNA level of AjRIG-Ibv was upregulated rapidly at 8 h after the Poly I:C injection, and the significant increase of AjRIG-Ib was observed at 16 and 24 h post-injection (hpi). Laser confocal microscopy showed that AjRIG-Ib and AjRIG-Ibv were both located in cytoplasm. In addition, the overexpression of AjRIG-Ib or AjRIG-Ibv led to the increased activity of IFN promoter in transient transfection assay. Taken together, our results indicated that AjRIG-Ib and AjRIG-Ibv may play cooperative or somewhat complementary roles in coordinating the antiviral response in fish.

Self-Assembly of Temperature Sensitive Unilamellar Vesicles by a Blend of Block Copolymers in Aqueous Solution

A self-assembled unilamellar vesicle, which can be used as a drug delivery system, was easily and simply fabricated using a blended system of Pluronic block copolymers. Controlling the hydrophilic mass fraction of block copolymers (by blending the block copolymer with a different hydrophilic mass fraction) and temperature (i.e., the hydrophobic interaction is controlled), a vesicular structure was formed. Small angle neutron scattering measurements showed that the vesicular structure had diameters of empty cores from 13.6 nm to 79.6 nm, and thicknesses of the bilayers from 2.2 nm to 8.7 nm when the hydrophobic interaction was changed. Therefore, considering that the temperature of the vesicle formation is controllable by the concentration of the blended block copolymers, it is possible for them to be applied in a wide range of potential applications, for example, as nanoreactors and nanovehicles.

Self-assembly of gold nanoparticles in a block copolymer aggregate template driven by hydrophobic interactions

We report various self-assembled structures of gold nanoparticles in a block copolymer aggregate template, which are easily driven by hydrophobic interactions.

Phosphodiesterase expression in the normal and failing heart

The number of patients with heart failure with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF) is increasing, and for HFpEF, no therapies have clinical benefit. It has been hypothesized that PKG attenuates pathological remodelling, and increasing cGMP would be beneficial for patients with HF. However, neither the RELAX nor NEAT-HFpEF trial showed benefit. But there is still enthusiasm for increasing cGMP in patients with HF, which highlight the need to determine the expression of PDEs in cardiac muscle. This study used immunoblotting to examine the expression of the PDEs that have been suggested to be targets for therapy of HF in both canines (normal and HFpEF) and humans (normal and HFrEF). Our results demonstrate PDE1C and PDE3A are expressed in cardiac muscle, but we could not detect the expression of PDE2A, PDE5A, PDE7A and PDE9A in cardiac tissue lysates from either normal or failing hearts. Thus, one should not expect a clinical benefit for a therapy targeting these PDEs in heart failure, which highlights the importance of rigorous demonstration of the target of therapy prior to undertaking a clinical trial.

Discontinued stimulation of cardiomyocytes provides protection against hypothermia-rewarming-induced disruption of excitation-contraction coupling

NEW FINDINGS

What is the central question of this study? Will discontinued stimulation of isolated cardiomyocytes (asystole) during hypothermia mitigate hypothermia-rewarming-induced cytosolic Ca²⁺ overload? What is the main finding and its importance? Mimicking asystole or hypothermic cardiac arrest by discontinued stimulation of cardiomyocytes during hypothermia resulted in normal contractile function after rewarming. This result suggests that asystole during severe hypothermia provides protection from hypothermia-rewarming-induced contractile dysfunction in cardiomyocytes.

ABSTRACT

After exposure of spontaneously beating hearts or electrically stimulated isolated cardiomyocytes to hypothermia-rewarming (H/R), cardiac dysfunction or alteration in excitation-contraction coupling, respectively, is a consequence. In contrast, hypothermic cardiac arrest, as routinely applied during cardiac surgery, will not impose any hazard to cardiac function after rewarming. We hypothesize that by maintaining asystole during H/R, cardiomyocytes will avoid Ca²⁺ overload attributable to the transient stimulation-evoked elevation of [Ca²⁺ ]_i and thus, H/R-induced elevation of phosphorylated cardiac troponin I and reduced Ca²⁺ sensitivity after rewarming. To test this hypothesis, the aim of the study was to determine whether discontinued electrical stimulation (to imitate hypothermic cardiac arrest) versus stimulation during 3 h of H/R prevents disruption of excitation-contraction coupling in our established cardiomyocyte H/R model. Cytosolic Ca²⁺ and the contractile response (sarcomere length shortening) were measured using an IonOptix system, and the dynamic assessment of Ca²⁺ sensitivity of contraction was conducted using a phase-loop plot. Cardiomyocytes were divided into three groups. Group 1 (time-matched control) was continuously stimulated at 0.5 Hz for 3 h at 35°C. Group 2 was continuously stimulated during H/R at 0.5 Hz, whereas in group 3 stimulation was discontinued during H/R and thus the cells remained quiescent until the resumption of stimulation after rewarming. The results demonstrate that discontinued stimulation of cardiomyocytes during H/R, imitating hypothermic cardiac arrest during cardiac surgery, provides protection against H/R-induced disruption of excitation-contraction coupling. We suggest that protective effects are caused by preventing the protein kinase A-induced elevation of phosphorylated cardiac troponin I, which is a key mechanism to reduce myofilament Ca²⁺ sensitivity of contraction.

Beam-induced redox transformation of arsenic during As K-edge XAS measurements: availability of reducing or oxidizing agents and As speciation

During X-ray absorption spectroscopy (XAS) measurements of arsenic (As), beam-induced redox transformation is often observed. In this study, the As species immobilized by poorly crystallized mackinawite (FeS) was assessed for the susceptibility to beam-induced redox reactions as a function of sample properties including the redox state of FeS and the solid-phase As speciation. The beam-induced oxidation of reduced As species was found to be mediated by the atmospheric O₂ and the oxidation products of FeS [e.g. Fe(III) (oxyhydr)oxides and intermediate sulfurs]. Regardless of the redox state of FeS, both arsenic sulfide and surface-complexed As(III) readily underwent the photo-oxidation upon exposure to the atmospheric O₂ during XAS measurements. With strict O₂ exclusion, however, both As(0) and arsenic sulfide were less prone to the photo-oxidation by Fe(III) (oxyhydr)oxides than NaAsO₂ and/or surface-complexed As(III). In case of unaerated As(V)-reacted FeS samples, surface-complexed As(V) was photocatalytically reduced during XAS measurements, but arsenic sulfide did not undergo the photo-reduction.

[Comparison of intensified myeloablative conditioning regime without antithymocytic globulin (ATG) with myeloablative conditioning regime for single-unit unrelated umbilical cord blood transplantation in hematological malignancies]

OBJECTIVE

To campare the effect and tolerance beween intensified myeloablative conditioning regime (IMCR) without antithymocyte globulin (ATG) and myeloablative conditioning regime (MCR) for single-unit unrelated umbilical cord blood transplantation (sUCBT) in hematological malignancies.

METHODS

The clinical data of 190 patients with hematological malignancies undergoing sUCBT between April 2000 and December 2013 at Department of Hematology, Anhui Provincial Hospital were retrospectively analyzed, of whom 156 received IMCR without ATG (IMCR group), including 79 patient receiving total body irradiation (TBI)/cytosine arabinoside (Ara-C)/cyclophosphamide (CY) regime, 47 receiving fludarabine (Flu)/busulfan (Bu)/CY regime, and 30 receiving Ara-C/Bu/CY regime, and all of the 156 received a combination of cyclosporine A (CsA) and mycophelonate mofetil (MMF) for the prophylaxis of graft-versus-host disease (GVHD); the remaining 34 patients received MCR (MCR group), 30 patients receiving Bu/CY regime, and 4 receiving TBI/CY regime, all using CsA/MMF±ATG or methotrexate (MTX) for the prophylaxis of GVHD. The two groups were compared in disease status at the time of transplantation, characteristics of graft, transplantation effect, and transplantation-related complications.

RESULTS

There were no statistically significant differences between the two groups in gender, disease type, human leukocyte antigen match, ABO blood type match, and disease status at the time of transplantation (all P>0.05). The median age and body weight at transplantation in the IMCR group were significantly higher than those in the MCR group (13 years vs 9 years, P=0.003; 44 kg vs 26 kg, P=0.000). The median doses of infused total nucleated cells (×10(7)/kg) and CD34(+) cells (×10(5)/kg) in the IMCR group were significantly lower than in the MCR group (3.87 vs 4.99, P=0.002; 2.00 vs 3.17, P=0.000). The cumulative incidence of myeloid engraftment on the 42th day and platelet engraftment on the 120th day in the IMCR group were remarkably higher than in the MCR group [96.33%(95%CI: 96.27%-96.39%)vs 82.30%(95%CI: 80.67%-83.93%), P=0.000; 86.44%(95%CI: 86.28%-86.60%)vs 51.17%(95%CI: 49.02%-53.32%), P=0.002]. There were no statistically significant differences in the incidences of grade Ⅱ to Ⅳ acute GVHD, grade Ⅲ to Ⅳ acute GVHD, and 2-year chronic GVHD(P=0.482, 0.928, 0.579). The incidence of pre-engraftment syndrome in the IMCR group was higher than in the MCR group(82.70% vs 47.06%, P=0.000). And 180-day transplantation-related mortality (TRM) in the IMCR group was lower than that in the MCR group [20.50%(95%CI: 20.28%-20.71%)vs 42.20% (95%CI: 41.32%-45.09%), P=0.004]. Up to October 2015, with a median follow-up of 44.2(22.7-188.9)months, the estimated 3-year overall survival and disease-free survival in the IMCR group were both significantly higher than those in the MCR group (62.90% vs 34.10%, P=0.000; 58.60% vs 34.10%, P=0.001).

CONCLUSION

IMCR without ATG may improve the engraftment without increasing complications, reduce early transplantation-related mortality, and improve survival.

[Pathogens and clinical characteristics of bacterial infection in hematology department between 2010 and 2014]

OBJECTIVE

To analyze the characteristics of distribution and drug resistance of bacterial infection in several different parts of hematology department inpatients of Anhui Provincial Hospital from January 2010 to December 2014, including patients who had received hematopoietic stem cell transplantation (HSCT).

METHODS

Anti-microbial susceptibility test was done by Kirby-Bauer method and automated systems and the data were analysed by WHONET 5.6 software.

RESULTS

A total of 3 312 copies of inspection samples were analyzed, including 2 716 (82%) blood samples and other 596 specimens (18%). 634 bacterial strains were isolated from 3 312 samples (19.14%) including 488 samples (76.97%) from blood culture. 427 (67.35%) bacterial strains were gram-negative, and the other 207 (32.65%) were gram-positive. Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa were most common gram-negative bacterial and the resistant rates to imipenem were 0.8%, 11.8% and 3.3%, respectively. Detection rates of Extended-spectrum beta-lactamases in Escherichia coli and Klebsiella pneumoniae were 83.9% and 75.0%, respectively. At the same time, Coagulase negative Staphylococcus, Streptococcus and Enterococcus were most common kinds of gram-positive bacteria. Methicillin-resistant coagulase negative staphylococcus accounted for 65.9% antibiotic resistance. No vancomycin and/or linezolid and/or tigecycline resistant strains of Staphylococcus spp. and Enterococcus spp. were found in those patients.

CONCLUSION

Patients with hematology diseases had a higher risk of bacterial infections, mainly caused by Gram-negative bacteria. There are different distributions of bacterial in different wards.

Hypothermia/rewarming disrupts excitation-contraction coupling in cardiomyocytes

Hypothermia/rewarming (H/R) is poorly tolerated by the myocardium; however, the underlying intracellular basis of H/R-induced cardiac dysfunction remains elusive. We hypothesized that in cardiomyocytes, H/R disrupts excitation-contraction coupling by reducing myofilament Ca(2+) sensitivity due to an increase in cardiac troponin I (cTnI) phosphorylation. To test this hypothesis, isolated rat cardiomyocytes (13-15 cells from 6 rats per group) were electrically stimulated to evoke both cytosolic Ca(2+) ([Ca(2+)]cyto) and contractile (sarcomere shortening) responses that were simultaneously measured using an IonOptix system. Cardiomyocytes were divided into two groups: 1) those exposed to hypothermia (15°C for 2 h) followed by rewarming (35°C; H/R); or 2) time-matched normothermic (35°C) controls (CTL). Contractile dysfunction after H/R was indicated by reduced velocity and extent of sarcomere length (SL) shortening compared with time-matched controls. Throughout hypothermia, basal [Ca(2+)]cyto increased and the duration of evoked [Ca(2+)]cyto transients was prolonged. Phase-loop plots of [Ca(2+)]cyto vs. contraction were shifted rightward in cardiomyocytes during hypothermia compared with CTL, indicating a decrease in Ca(2+) sensitivity. Using Western blot, we found that H/R increases cTnI phosphorylation. These results support our overall hypothesis and suggest that H/R disrupts excitation-contraction coupling of cardiomyocytes due to increased cTnI phosphorylation and reduced Ca(2+) sensitivity.

Secondary angle closure glaucoma by lupus choroidopathy as an initial presentation of systemic lupus erythematosus: a case report

BACKGROUND

We present a rare case of secondary angle closure glaucoma due to systemic lupus erythematosus choroidopathy as initial presentation of systemic lupus erythematosus, accompanied by central nervous system vasculitis and uncontrolled nephropathy.

CASE PRESENTATION

A 31-year-old woman presented with decreased visual acuity, nausea, vomiting, fever, and bilateral angioedema-like eyelid swelling. She had persistent dry cough while taking medication for 3 months, and had usual posterior neck pain, which was treated with analgesic medication and Asian medicines. Intraocular pressure was 32 and 34 mmHg in her right and left eyes, respectively. Peripheral anterior chambers were shallow (grade I) using the van Herick method. Gonioscopy revealed 360° closed angle in both eyes. In both eyes, serous retinal detachment was found using optical coherence tomography and B scan ultrasonography, as well as choroidal thickening with effusion. Secondary acute angle closure glaucoma was drug induced, or caused by uveitis of unknown etiology when she was first treated with intraocular pressure-lowering medication. During evaluation of the drug-induced angioedema in the internal medicine department, systemic lupus erythematosus was diagnosed, based on malar rash, photosensitivity, proteinuria, and positive anti-Smith and anti-DNA antibodies, followed by initiation of steroid pulse therapy. Using fluorescein angiography, multifocal subretinal pinpoint foci were detected at the middle phase. We then diagnosed bilateral angle closure glaucoma by choroidal effusions, with lupus choroidopathy. At 2 months after steroid pulse therapy, subretinal fluid was not found, and visual acuity improved to normal. During the subsequent 2 years, lupus choroidopathy was not aggravated but lupus nephritis was not controlled.

CONCLUSION

Patients with systemic lupus erythematosus choroidopathy can develop ciliochoroidal effusion, which can lead to acute angle closure glaucoma. Systemic lupus erythematosus choroidopathy is an early sign of severe complications. Angle closure glaucoma by systemic lupus erythematosus choroidopathy can be effectively treated using antiglaucoma drugs and immunosuppressive therapy.

Optimal central venous pressure during the neohepatic phase to decrease peak portal vein flow velocity for the prevention of portal hyperperfusion in patients undergoing living donor liver transplantation

BACKGROUND

The association between intraoperative systemic hemodynamic status and preventing portal hyperperfusion, which induces shear stress on the sinusoidal endothelial cells of liver grafts, resulting in poor graft function in live-donor recipients, has not been identified. This study evaluates the effects of systemic hemodynamic parameters (SHPs) during the neohepatic phase on changes in hepatic hemodynamic parameters (HHPs) between the neohepatic phase and the 1st postoperative day.

METHODS

Thirty-eight patients undergoing living donor liver transplantation (LDLT) were enrolled in this study. HHPs (flow velocities of portal vein and hepatic artery) were measured immediately after hepatic artery and bile duct reconstruction and on the first postoperative day. SHPs (mean arterial pressure, central venous pressure [CVP], cardiac index, stroke volume variation, stroke volume index, systemic vascular resistance index, and central venous oxygen saturation) were recorded and averaged for 5 minutes after the measurement of HHPs. The relationships between the SHPs and HHPs were assessed using linear or quadratic regression analysis.

RESULTS

Peak portal vein flow velocity (PVV) decreased on the 1st postoperative day in 24 patients (63%). There was an inverted-U relationship between CVP and the percentage change in PVV (R(2) = 0.241, P = .008). According to the quadratic regression model, the PVV maximally decreased at a CVP of 7.8 mm Hg. No significant correlations were found between the other SHPs and HHPs.

CONCLUSIONS

Maintaining CVP (approximately 8 mm Hg) during the neohepatic phase was clinically beneficial in decreasing PVV to prevent portal hyperperfusion in the early postoperative period of LDLT.

Fourteen successful consecutive cases of ABO-incompatible living donor liver transplantation: new simplified intravenous immunoglobulin protocol without local infusion therapy

Since various innovative strategies including local infusion therapy and rituximab have been introduced, the survivals and outcomes of recipients in ABO-incompatible (ABO-I) living donor liver transplantation (LDLT) have remarkably improved. Thus, ABO-I LDLT can be a feasible therapeutic option for the patient with end-stage liver disease if an ABO-compatible donor is not available. Although most ABO-I protocols are based on rituximab, plasma exchange, and local infusion therapy, treatment strategies have been changing according to a center's preference or their results. Nonetheless, the consensus of the ABO-I LDLT protocol remains undetermined. Herein, we present our experience with new simple ABO-I LDLT protocol and the excellent results for 14 patients from January 2011 to May 2013. All patients were administrated a single dose of rituximab over 7 days before transplantation followed by plasma exchange to lower anti-ABO antibody titer ≤32. The basic immunosuppression protocol consisted of tacrolimus and steroids with mycophenolate mofetil starting 3 days before transplantation. Splenectomy was not performed routinely and local infusion therapy was not applied at the postoperative period. Instead, the patients received intravenous immunoglobulin (IVIG) after LDLT on days 1, 3, and 5. Neither antibody-mediated rejection nor biliary stricture were encountered in the patients, with a mean follow-up of 16.27 ± 9.4 months. This new simplified ABO-I LDLT protocol seems to prevent antibody-mediated rejection and could be considered as the safe and effective modality to overcome the ABO blood-type barrier in LDLT.

Human heart failure is accompanied by altered protein kinase A subunit expression and post-translational state

β-Adrenergic receptor blockade reduces total mortality and all-cause hospitalizations in patients with heart failure (HF). Nonetheless, β-blockade does not halt disease progression, suggesting that cAMP-dependent protein kinase (PKA) signaling downstream of β-adrenergic receptor activation may persist through unique post-translational states. In this study, human myocardial tissue was used to examine the state of PKA subunits. As expected, total myosin binding protein-C phosphorylation and Ser23/24 troponin I phosphorylation significantly decreased in HF. Examination of PKA subunits demonstrated no change in type II regulatory (RIIα) or catalytic (Cα) subunit expression, although site specific RIIα (Ser96) and Cα (Thr197) phosphorylation were increased in HF. Further, the expression of type I regulatory subunit (RI) was increased in HF. Isoelectric focusing of RIα demonstrated up to three variants, consistent with reports that Ser77 and Ser83 are in vivo phosphorylation sites. Western blots with site-specific monoclonal antibodies showed increased Ser83 phosphorylation in HF. 8-fluo-cAMP binding by wild type and phosphomimic Ser77 and Ser83 mutant RIα proteins demonstrated reduced Kd for the double mutant as compared to WT RIα. Therefore, failing myocardium displays altered expression and post-translational modification of PKA subunits that may impact downstream signaling.

Altered reactivity of tertiary mesenteric arteries following acute myocardial ischemia

BACKGROUND

It is unknown if cardiac ischemia has any deleterious effect on the contractile properties of nonischemic, peripheral vascular beds. Thus, the objective of the present study was to determine whether acute myocardial ischemia results in peripheral vascular dysfunction.

METHODS AND RESULTS

This study characterized force maintenance and the sensitivity to acetylcholine (ACh)-mediated smooth muscle (SM) relaxation of tertiary (3rd) mesenteric arteries from Sprague-Dawley rats following 30 min of myocardial ischemia. Both the phosphorylation of nonmuscle (NM) light chain (LC) and SM-LCs as well as the expression of myosin phosphatase targeting subunit 1 (MYPT1) were also determined. Our data demonstrate that acute myocardial ischemia resulted in vascular dysfunction of 3rd mesenteric vessels, characterized by decreases in force maintenance, ACh- and cGMP-mediated SM relaxation, the phosphorylation of NM-LCs and SM-LCs, and MYPT1 expression. Ischemia was also associated with an increase in protein polyubiquitination, suggesting that during ischemia MYPT1 is targeted for degradation or proteolysis.

CONCLUSION

Acute myocardial ischemia produces peripheral vascular dysfunction; the changes in LC phosphorylation and MYPT1 expression result in a decrease in both tone and the sensitivity to NO-mediated SM relaxation of the peripheral vasculature.

Acute insulin resistance following surgical trauma in rats

OBJECTIVE

To unravel the possible mechanism of acute posttraumatic insulin resistance in rats.

METHODS

Resection of small intestine was performed to establish the surgical trauma model. The blood glucose and serum insulin level were detected and the HOMA index was calculated. The Hyperinsulinemic-euglycemic clamp was performed to investigate the glucose disposal rate by peripheral tissue. The content and phosphorylation state of IRS-1, p85 of PI3-K and PKB/Akt in skeletal muscle were measured respectively. Finally, the [3H] labeled glucose uptake experiment was carried out.

RESULTS

The blood glucose elevated significantly after resection of small intestine in rats. The level of serum insulin decreased during the first 30 min after operation but elevated in the following time. The HOMA-IR in trauma group was significantly greater than control group; however the HOMA-β in trauma group was less than control group. The glucose disposal rate was decreased 49% after operation. The p-IRS-1(Ser307) was significantly enhanced 95% after trauma while the p-IRS-1 (Tyr612) was attenuated by 38%. The phosphorylation of its downstream target, p-PKB/Akt(Ser473) was attenuated by 48%. Accordingly, the glucose uptaken by skeletal muscle was significantly decreased in trauma group.

CONCLUSION

We demonstrated the posttraumatic insulin resistance occurred soon after surgical trauma in rats. The level of insulin was relatively insufficient because of the decreased sensitivity in peripheral tissue. Trauma induced Ser phosphorylation instead of Tyr phosphorylation eliminated the ability of IRS-1 to activate downstream effector molecules such as PKB/Akt and resulted in severe impairment of insulin signal transduction and glucose transport in skeletal muscle.

Molecular cloning and characterization of the STAT gene in Hyphantria cunea haemocytes

A new insect member of the signal transducer and activator of transcription (STAT) family of transcription factors, Hyphantria cunea STAT (HcSTAT), was cloned from the lepidopteran H. cunea. The domain involved in DNA interaction and the Src homology 2 (SH2) domain were well conserved. During all developmental stages, the gene was expressed at a low level in the haemocytes, fat body cells, midgut, epidermis and Malpighian tubules. The haemocytes and Malpighian tubules showed transcriptional activation of HcSTAT upon Gram-negative and Gram-positive bacterial challenges. These challenges increased the induction and nuclear translocation of the HcSTAT protein that recognizes a STAT target site in H. cunea haemocytes. In vivo treatment with sodium orthovanadate translocated HcSTAT to the haemocyte nucleus. This study shows the involvement of the haemocyte Janus kinase/STAT pathway after microbial infection in lepidopteran insects.

Homologous expression and quantitative analysis of T3SS-dependent secretion of TAP-tagged XoAvrBs2 in Xanthomonas oryzae pv. oryzae induced by rice leaf extract

Xanthomonas oryzae pv. oryzae (Xoo) produces a putative effector, XoAvrBs2. We expressed XoAvrBs2 homologously in Xoo with a TAP-tag at the C-terminus to enable quantitative analysis of protein expression and secretion. Addition of rice leaf extracts from both Xoo-sensitive and Xoo-resistant rice cultivars to the Xoo cells induced expression of the XoAvrBs2 gene at the transcriptional and translational levels, and also stimulated a remarkable amount of XoAvrBs2 secretion into the medium. In a T3SS-defective Xoo mutant strain, secretion of the TAPtagged XoAvrBs2 was blocked. Thus, we elucidated the transcriptional and translational expressions of the XoAvrBs2 gene in Xoo was induced in vitro by the interaction with rice and the induced secretion of XoAvrBs2 was T3SSdependent. It is the first report to measure the homologous expression and secretion of XoAvrBs2 in vitro by rice leaf extract. Our system for the quantitative analysis of effector protein expression and secretion could be generally used for the study of host-pathogen interactions.

Force relaxation and thin filament protein phosphorylation during acute myocardial ischemia

Ischemia impairs myocardial function and may contribute to the progression of heart failure. In this study, rats subjected to acute ischemia demonstrated reduced Ca(2+) -activated force as well as a decrease in myosin-binding protein-C, titin, and Ser23/24 phosphorylation of troponin I (TnI). All three proteins have been demonstrated to be downstream targets of β-adrenergic receptor activation (β-AR), leading to the hypothesis that decreased β-AR signaling during ischemia leads to reduced protein phosphorylation and reduced rate constants of force relaxation. To test this hypothesis, force relaxation transients were recorded from permeabilized perfused and ischemic rat heart fibers following photolysis of the caged chelator diazo-2. Relaxation transients were best fit by double exponential functions whereby the majority (>70%) of the force decline was described by the fast rate constant, which was ∼5 times faster than the slow rate constant. However, rate constants of relaxation between perfused and ischemic fibers were not different, despite significant decreases in sarcomeric protein phosphorylation in ischemic fibers. Treatment of perfused fibers with a cAMP analog increased Ser23/24 phosphorylation of TnI, yet the rate constants of relaxation remained unchanged. Interestingly, similar treatment of ischemic fibers did not impact TnI phosphorylation or force relaxation transients. Therefore, acute ischemia does not influence the rate constants of relaxation of permeabilized fibers. These results also suggest that the physiological level of sarcomeric protein phosphorylation is unlikely to be the primary driver of relaxation kinetics in permeabilized cardiac muscle fibers.

Nimesulide, a selective COX-2 inhibitor, acts synergistically with ionizing radiation against A549 human lung cancer cells through the activation of caspase-8 and caspase-3

Several lines of evidence suggest that non-steroidal anti-inflammatory drugs (NSAIDs) have a radiosensitizing effect on cancer cells in vitro and in vivo, but little is known about the underlying cellular mechanism. In this study, we found that the treatment with the NSAID nimesulide significantly increased the sensitivity of A549 human non-small cell lung cancer cells to radiotherapy. The combined nimesulide-radiation treatment increased apoptosis, induced the cleavage of caspase-3, caspase-9, and poly(ADP-ribose) polymerase (PARP), activated caspase-8, and induced cleavage of Bid. A pan-caspase inhibitor, z-VAD-fmk, suppressed this increase in apoptosis and also suppressed the cleavage of caspase-8, caspase-3, and PARP, suggesting a caspase-dependent mechanism. In addition, z-IETD-fmk, a selective caspase-8 inhibitor, suppressed the nimesulide- and radiation-induced cleavage activation of caspase-9, caspase-3, caspase-8, and Bid, and suppressed the concomitant apoptosis, indicating that the nimesulide-induced increase in radiosensitivity was initiated by caspase-8. However, the caspase-3 inhibitor z-DEVD-fmk failed to suppress activation of the caspase-8/Bid pathway, indicating that caspase-3 activation occurred downstream of caspase-8 activation in our experiments. Marked antitumor effects, which were evaluated by measuring protracted tumor regression, were observed when nude mice were treated with a combination of nimesulide at a clinically achievable dose (0.5 mg/kg) and radiation therapy. Our results, demonstrating the radiosensitivity-increasing and tumor growth-inhibiting effects of nimesulide, suggest that nimesulide may be suitable as an adjuvant to enhance the efficacy and selectivity of radiotherapy.

Small-angle neutron scattering study of the miscibility of metallocene-catalyzed octene linear low-density polyethylene and low-density polyethylene blends

Small-angle neutron scattering (SANS) analysis was performed to investigate the miscibility of blends of metallocene-catalyzed octene linear low-density polyethylene (octene-mLLDPE) and low-density polyethylene (LDPE). The quantitative SANS analysis found that the blends are miscible in both the melt and the quenched states. Moreover, this analysis confirmed that the radii of gyration of octene-mLLDPE(D) and LDPE(H) remain unchanged in the quenched state and that the two polymer components cocrystallizeviafast crystallization from the melt state.

Benefit and pitfalls of newborn hearing screening

The importance of universal newborn hearing screening (UNHS) in identifying hearing-impaired infants as early as possible is already well recognized. Transient evoked otoacoustic emissions (TEOAE) have been established as a reliable method for UNHS in full term infants. This is a cross sectional study between April 2003--December 2005. Thirteen thousand five hundred and ninety eight (13,598) newborns were screened for hearing loss with portable otoacoustic emission (OAE) before discharge. The initial coverage rate during the 3 years study period was 85.9% (13,598) with 89.2% (3762), 79.0% (4480) and 90.3% (5356) for 2003, 2004 and 2005 respectively. The mean age when hearing loss was diagnosed using ABR were 3.56 months old, 3.08 months old, and 2.25 months old and 3.01 months old for 2003, 2004, 2005 respectively and it was statistically significant. The defaulter rate at the third stage during the 3 years study period was 35% (21), 15.2% (7) and 18.2% (2) for 2003, 2004 and 2005 respectively. This study showed significant improvement in initial referral rate, coverage rate and age of diagnosis. However, we need to improve on high defaulter rates.

Functional changes in a novel uracil-DNA glycosylase determined by mutational analyses

Uracil-DNA glycosylase (UDG) is a ubiquitous enzyme found in bacteria and eukaryotes, which removes uracil residues from DNA strands. Methanococcus jannaschii UDG (MjUDG), a novel monofunctional glycosylase, contains a helix-hairpin-helix (HhH) motif and Gly/Pro rich loop (GPD region), which is important for catalytic activity; it shares these features with other glycosylases such as endonuclease III. First, to examine the role of two conserved amino acid residues (Asp150 and Tyr152) in the HhH-GPD region of MjUDG, mutant MjUDG proteins were constructed, in which Asp 150 was replaced with either Glu or Trp (D150E and D150W), Tyr152 was replaced with either Glu or Asn (Y152E and Y152N). Mutant D150W completely lacked DNA glycosylase activity, whereas D150E displayed reduced activity of about 70% of the wild type value. However, the mutants Y152E and Y152N retained unchanged levels of UDG activity. We also replaced Glu132 in the HhH motif with a lysine residue equivalent to Lys120 in endonuclease III. This mutation converted the enzyme into a bifunctional glycosylase/AP lyase capable of both removing uracil at a glycosylic bond and cleaving the phosphodiester backbone at an AP site. Mutant E132K catalyzes a beta-elimination reaction at the AP site via uracil excision and forms a Schiff base intermediate in the form of a protein-DNA complex.

Comparative analysis of two attacin genes from Hyphantria cunea

A full-length clone corresponding to attacin was isolated from a cDNA library made from fat body of immunized Hyphantria cunea larvae. This newly isolated attacin B shows characteristics different from those previously reported for attacin A. The two attacin cDNAs encode precursor proteins of 233 and 248 amino acid residues, respectively. The two attacins show 45.9% identity at the amino acid level, and 35.2% identity at the nucleotide level. Attacins A and B of H. cunea show significant identities with the attacins of Lepidoptera. Attacin B is a typical glycine-rich protein, while attacin A is leucine-rich. Attacin B is expressed from last instar larvae to adult, while attacin A showed stage-specific expression during the prepupal and pupal stages. Attacins A and B are predicted to have different secondary structure in that attacin A has no tendency to form helices but attacin B contains a substantial number of helices. Attacin A is induced at a trace level in infected larvae, while attacin B is strongly induced against Gram-positive and negative bacteria, fungi, and viruses. The attacin B transcripts were detected in fat body, epidermis and hemocytes after injection with Escherichia coli, Citrobacter freundii, or Candida albicans, but not in the midgut and Malpighian tubule. Recombinant attacin A showed no antibacterial activity, while recombinant attacin B showed strong antibacterial activity in proportion to the amount of the protein injected.