Erratum: Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande [Phys. Rev. Lett. 130, 031802 (2023)]

This corrects the article DOI: 10.1103/PhysRevLett.130.031802.

Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande

We report a search for cosmic-ray boosted dark matter with protons using the 0.37  megaton×years data collected at Super-Kamiokande experiment during the 1996-2018 period (SKI-IV phase). We searched for an excess of proton recoils above the atmospheric neutrino background from the vicinity of the Galactic Center. No such excess is observed, and limits are calculated for two reference models of dark matter with either a constant interaction cross section or through a scalar mediator. This is the first experimental search for boosted dark matter with hadrons using directional information. The results present the most stringent limits on cosmic-ray boosted dark matter and exclude the dark matter-nucleon elastic scattering cross section between 10^{-33}cm^{2} and 10^{-27}cm^{2} for dark matter mass from 1  MeV/c^{2} to 300  MeV/c^{2}.

Serum interleukin-17A/interferon-gamma ratio as a predictor for the severity of atrial low voltage in atrial fibrillation: from FIB-MARK study

Background

Atrial fibrosis is hallmark of structural remodeling in atrial fibrillation (AF), but the inflammatory mechanism remains unclear. The purpose of the present study was to identify the specific inflammatory biomarkers to atrial fibrosis evaluated by atrial low voltage (LV) in AF patients for clarification of the mechanism.

Methods

Forty inflammatory biomarkers were quantified in 16 consecutive AF patients measured left atrial low voltage during catheter ablation.

Results

Median %LV area was 17%. In Pearson's correlation analysis, interleukin (IL)-17A and interferon (IFN)-γ was the most significant positive and negative correlation with %LV (R=0.35 and 0.43, P<0.001). Furthermore, there was a significant correlation between IL-17A/IFN-γ ratio and %LV (R=0.65, P=0.007). The area under the receiver operator characteristics curve of IL-17A/IFN-γ ratio for significant LV (%LV >10% as a reference standard) was 0.88. IL-17A/IFN-γ ratio was significantly higher in patients with significant LV than those without (1.41 versus 0.97, P=0.01), Furthermore, the sensitivity, specificity, and accuracy for detecting significant LV were 60%, 100%, and 75.0% at the cutoff value of 1.3. The event free survival from recurrent atrial tachyarrhythmias was not significantly different between patients with and without IL-17A/IFN-γ ratio >1.3 (83.3% versus 80.0% at 1-year, P=0.81).

Conclusions

Among inflammatory biomarkers, IL-17A/IFN-γ ratio was a significant predictor for the severity of left atrial low voltage n AF patients. Further study is needed to reveal the association between IL-17A and IFN-γ for development of fibrosis in AF.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): JSPS KAKENHI GrantNumber JP19K17594

Long-term outcomes evaluated by device-monitored physical activity in patients with implantable cardiac defibrillator or cardiac resynchronization therapy device

Background

The patients with implantable cardiac defibrillator (ICD) or cardiac resynchronization therapy device (CRT) have high risk of cardiac events, and lower physical activity has been thought to be associated with higher rate of cardiac events. On the other hand, cardiovascular implantable electronic devices can monitor physical activity through a built-in accelerometer. This study aimed to analyze long-term outcomes by device-based monitoring of physical activity in patients with ICD or CRT.

Methods

We retrospectively reviewed 89 patients with ICD/CRT, (56 males, 66.5 years old; ICD 45, CRT-D 42, CRT-P 2) who survived longer than 6 months after implantation in our institution. We analyzed physical activity by devices at 6th month and divided to 2 groups; In Low activity group (group L; n=38), their physical activity (moving time above 70 steps/min walk level) is less than 2 hours/day, and in Normal activity group (group N; n=51), physical activity is more than 2 hours/day. We evaluated their background characteristics in each group, physical activity at 12th month, and composite outcomes of hospitalization due to worsening of heart failure (HF) and death of any cause.

Results

Mean follow-up period was 57.4 months (median 40 months). In group L, they had higher age (71.1 y.o. vs. 63.2 y.o.; p=0.0003), higher rate of low EF (76.3% vs. 54.9%; p=0.035), and lower rate of attendance to outpatient cardiac rehabilitation program (10.5% vs 27.5%; p=0.043) compared with group N. 85.7% of patients in group L stayed in low physical activity at 12th month, and 87.8% of patient in group N stayed in normal physical activity. Composite outcomes of HF hospitalization and death occurred significantly higher in group L (Log-rank p<0.0001; 29.0% vs. 5.9% at 1 year, and 68.7% vs. 16.2% at 3 year: Figure 1) than in group N. Each event, HF hospitalization and death of any cause were shown significantly higher in group L (Log-rank p<0.0001). In group L, mortality rate of patients who could improve their physical activity from 6th month to 12th month was significantly lower than patients who stayed in low physical activity (Log-rank p=0.038).

Conclusions

Lower level of device-monitored physical activity was associated with higher mortality and higher rate of HF hospitalization in patients with ICD or CRT. Most of the patient in lower physical activity could not improve their activity from 6th month to 12th month. Early and continuous intervention is necessary especially for high risk patients such as high age or low EF.

Figure 1

Funding Acknowledgement

Type of funding source: None

Neofusicoccum parvum Colonization of the Grapevine Woody Stem Triggers Asynchronous Host Responses at the Site of Infection and in the Leaves

Grapevine trunk diseases cause important economic losses in vineyards worldwide. Neofusicoccum parvum, one of the most aggressive causal agents of the trunk disease Botryosphaeria dieback, colonizes cells and tissues of the grapevine wood, leading to the formation of an internal canker. Symptoms then extend to distal shoots, with wilting of leaves and bud mortality. Our aim was to characterize the transcriptional dynamics of grapevine genes in the woody stem and in the leaves during Neofusicoccum parvum colonization. Genome-wide transcriptional profiling at seven distinct time points (0, 3, and 24 hours; 2, 6, 8, and 12 weeks) showed that both stems and leaves undergo extensive transcriptomic reprogramming in response to infection of the stem. While most intense transcriptional responses were detected in the stems at 24 hours, strong responses were not detected in the leaves until the next sampling point at 2 weeks post-inoculation. Network co-expression analysis identified modules of co-expressed genes common to both organs and showed most of these genes were asynchronously modulated. The temporal shift between stem vs. leaf responses affected transcriptional modulation of genes involved in both signal perception and transduction, as well as downstream biological processes, including oxidative stress, cell wall rearrangement and cell death. Promoter analysis of the genes asynchronously modulated in stem and leaves during N. parvum colonization suggests that the temporal shift of transcriptional reprogramming between the two organs might be due to asynchronous co-regulation by common transcriptional regulators. Topology analysis of stem and leaf co-expression networks pointed to specific transcription factor-encoding genes, including WRKY and MYB, which may be associated with the observed transcriptional responses in the two organs.

Chip-based quantum key distribution

Improvement in secure transmission of information is an urgent need for governments, corporations and individuals. Quantum key distribution (QKD) promises security based on the laws of physics and has rapidly grown from proof-of-concept to robust demonstrations and deployment of commercial systems. Despite these advances, QKD has not been widely adopted, and large-scale deployment will likely require chip-based devices for improved performance, miniaturization and enhanced functionality. Here we report low error rate, GHz clocked QKD operation of an indium phosphide transmitter chip and a silicon oxynitride receiver chip—monolithically integrated devices using components and manufacturing processes from the telecommunications industry. We use the reconfigurability of these devices to demonstrate three prominent QKD protocols—BB84, Coherent One Way and Differential Phase Shift—with performance comparable to state-of-the-art. These devices, when combined with integrated single photon detectors, pave the way for successfully integrating QKD into future telecommunications networks.

Quantum key distribution has not been widely adopted in part due to technical hurdles preventing it being fully integrated in classical communication networks. Here the authors report quantum key distribution between two photonic chips manufactured with state-of-the-art telecoms industry processes.

Simple 40K removal by acidified water leaching for estimating low levels of radiocesium in fishery products following Fukushima Dai-ichi Nuclear Power Plant accident

We developed a simple method for ⁴⁰K removal by acidified water leaching combined with ammonium phosphomolybdate coprecipitation, for estimating low levels of radiocesium in Japanese flounder. ⁴⁰K removal from ashed samples was approximately 98%, with the radiocesium yield of ~98%. The treatment reduced the γ-spectral baseline to ~1/5 at ground and ~3/100 at underground levels (1.04 and 0.11 cph/keV, respectively). Faint signal of ¹³⁴Cs, which is embedded in the Compton continuum of ⁴⁰K in an untreated sample, was detected.

Experimental Evaluation of the Anchoring Efficiency of Bone Cement under Various Conditions, and Improved Cementing Techniques and Instrumentations for Total Hip Replacement

Viscoelastic properties of acrylic bone cement were studied by using a simplified controlled laboratory model simulating a component cementing in total hip replacement surgery. This study also dealt with improved cementing techniques developed through these experimental studies.

Computer-Assisted Detection of Cerebral Aneurysms in MR Angiography in a Routine Image-Reading Environment: Effects on Diagnosis by Radiologists

BACKGROUND AND PURPOSE

Experiences with computer-assisted detection of cerebral aneurysms in diagnosis by radiologists in real-life clinical environments have not been reported. The purpose of this study was to evaluate the usefulness of computer-assisted detection in a routine reading environment.

MATERIALS AND METHODS

During 39 months in a routine clinical practice environment, 2701 MR angiograms were each read by 2 radiologists by using a computer-assisted detection system. Initial interpretation was independently made without using the detection system, followed by a possible alteration of diagnosis after referring to the lesion candidate output from the system. We used the final consensus of the 2 radiologists as the reference standard. The sensitivity and specificity of radiologists before and after seeing the lesion candidates were evaluated by aneurysm- and patient-based analyses.

RESULTS

The use of the computer-assisted detection system increased the number of detected aneurysms by 9.3% (from 258 to 282). Aneurysm-based analysis revealed that the apparent sensitivity of the radiologists' diagnoses made without and with the detection system was 64% and 69%, respectively. The detection system presented 82% of the aneurysms. The detection system more frequently benefited radiologists than being detrimental.

CONCLUSIONS

Routine integration of computer-assisted detection with MR angiography for cerebral aneurysms is feasible, and radiologists can detect a number of additional cerebral aneurysms by using the detection system without a substantial decrease in their specificity. The low confidence of radiologists in the system may limit its usefulness.

Characterization and evolutionary analysis of tributyltin-binding protein and pufferfish saxitoxin and tetrodotoxin-binding protein genes in toxic and nontoxic pufferfishes

Understanding the evolutionary mechanisms of toxin accumulation in pufferfishes has been long-standing problem in toxicology and evolutionary biology. Pufferfish saxitoxin and tetrodotoxin-binding protein (PSTBP) is involved in the transport and accumulation of tetrodotoxin and is one of the most intriguing proteins related to the toxicity of pufferfishes. PSTBPs are fusion proteins consisting of two tandem repeated tributyltin-binding protein type 2 (TBT-bp2) domains. In this study, we examined the evolutionary dynamics of TBT-bp2 and PSTBP genes to understand the evolution of toxin accumulation in pufferfishes. Database searches and/or PCR-based cDNA cloning in nine pufferfish species (6 toxic and 3 nontoxic) revealed that all species possessed one or more TBT-bp2 genes, but PSTBP genes were found only in 5 toxic species belonging to genus Takifugu. These toxic Takifugu species possessed two or three copies of PSTBP genes. Phylogenetic analysis of TBT-bp2 and PSTBP genes suggested that PSTBPs evolved in the common ancestor of Takifugu species by repeated duplications and fusions of TBT-bp2 genes. In addition, a detailed comparison of Takifugu TBT-bp2 and PSTBP gene sequences detected a signature of positive selection under the pressure of gene conversion. The complicated evolutionary dynamics of TBT-bp2 and PSTBP genes may reflect the diversity of toxicity in pufferfishes.

Localization and interaction effects in ultrathin epitaxial NbN superconducting films

For epitaxial NbN films with thickness d, 2.0 nm ≤ d ≤ 20.5 nm, we observed a sharp superconducting transition, for which the transition temperature T(c) monotonically decreased with increasing 1/d. Regarding the suppression of T(c), the sheet resistance R(sq) dependence of T(c) closely fitted the Finkel'stein formula from localization theory, with a reasonable value of the electron mean free path comparable to atomic distance, which was used as a fitting parameter. On the other hand, the critical sheet resistance R(c), at which the superconducting-insulator transition was expected, was approximately one-third of the universal value R(q) = h/4e(2) suggested by the dirty boson model for self-duality. It is concluded that T(c) depression in the present NbN system is determined by localization theory but not the dirty boson model.

Afterpulse-like phenomenon of superconducting single photon detector in high speed quantum key distribution system

We discuss our estimates of the performance of a superconducting single photon detector (SSPD) in a high speed quantum key distribution (QKD) system. We find that at high repetition operation reflections from the readout circuit at room temperature causes an afterpulse-like phenomenon, and drastically increases the quantum bit error rate (QBER). Such effects are not seen during low frequency operation. By using an amplifier with a small reflection coefficient S11, we succeed in reducing the afterpulse-like phenomenon and increasing a secure key rate.

Field test of quantum key distribution in the Tokyo QKD Network

A secure communication network with quantum key distribution in a metropolitan area is reported. Six different QKD systems are integrated into a mesh-type network. GHz-clocked QKD links enable us to demonstrate the world-first secure TV conferencing over a distance of 45km. The network includes a commercial QKD product for long-term stable operation, and application interface to secure mobile phones. Detection of an eavesdropper, rerouting into a secure path, and key relay via trusted nodes are demonstrated in this network.

Charge-state-derivation ion detection using a super-conducting nanostructure device for mass spectrometry

Mass spectrometry (MS) is a method of analyzing ions based on their mass/charge (m/z) ratios. The m/z peak identification requires speculation on the ionic unit-charge states. This problem can be solved by using superconducting junction devices to measure the kinetic energies of single molecules. However, the kinetic energy measurement is followed by the dead time of 1-20 µs, which is fatally slow for modern high-resolution time-of-flight (TOF) analyzers. In this paper, we demonstrate that a superconducting nano-stripline detector (SSLD) composed of a 10-nm-thick and 800-nm-wide NbN strip realizes the charge-state derivation, and furthermore satisfies the ideal MS detector specifications such as a nano-second response, a short recovery time, a wide mass range, and no noise.

Long-distance entanglement-based quantum key distribution over optical fiber

We report the first entanglement-based quantum key distribution (QKD) experiment over a 100-km optical fiber. We used superconducting single photon detectors based on NbN nanowires that provide high-speed single photon detection for the 1.5-mum telecom band, an efficient entangled photon pair source that consists of a fiber coupled periodically poled lithium niobate waveguide and ultra low loss filters, and planar lightwave circuit Mach-Zehnder interferometers (MZIs) with ultra stable operation. These characteristics enabled us to perform an entanglement-based QKD experiment over a 100-km optical fiber. In the experiment, which lasted approximately 8 hours, we successfully generated a 16 kbit sifted key with a quantum bit error rate of 6.9 % at a rate of 0.59 bits per second, from which we were able to distill a 3.9 kbit secure key.

Lower brainstem dysfunction in an infant with persistent primitive trigeminal artery

A 6-month-old boy with persistent primitive trigeminal artery (PPTA) presented with stridor, dysphagia, delayed motor development and postural neck and shoulder dystonia. Magnetic resonance imaging/angiography and ultrasonography revealed PPTA, with flow from the dilated basilar artery to the right internal carotid artery, lower brainstem compression by the dilated basilar artery, and cerebellar vermis hypoplasia. Evoked potentials showed lower pons and medulla oblongata functional disruption. These lesions may be related to vascular etiology in the lower brainstem or to congenital malformation syndrome involving infratentorial structures. The relationship of this condition to Möbius syndrome is discussed.

The role of the hypothalamic nitric oxide in the pressor responses elicited by acute environmental stress in awake rats

We quantitatively investigated the change in nitric oxide (NO) in the hypothalamic paraventricular nucleus (PVN) and its effect on cardiovascular regulation during shaker stress (SS) using brain microdialysis in awake rats. Male Wistar rats were fed either N(G)-nitro-L-arginine methyl ester (L-NAME, 0.7 g/L) or tap water for 2 weeks. Two days after implantation of an arterial catheter and guide shaft, a microdialysis probe was placed to perfuse the PVN with degassed Ringer solution at 2 microl/min in awake normotensive Wistar (CONTROL) and chronic L-NAME-treated hypertensive rats. After the rat was placed in a plastic cage set on a shaker, the blood pressure and heart rate was monitored and 10-min SS was loaded at a frequency of 200 cycles/min. Dialysate samples were analyzed by NO analyzer (based on the Griess reaction) every 10 min, and NOx (NO(2)(-) + NO(3)(-)) was measured. Plasma NOx was also measured before and after SS. Pressor responses elicited by SS were significantly greater in L-NAME-treated rats than in the CONTROL. Although NOx in the PVN dialysate were increased by SS in the CONTROL, these responses were attenuated in chronic L-NAME-treated rats. Resting plasma NOx were higher in the CONTROL than in L-NAME-treated rats. SS elicited no difference between two groups in plasma NOx. These results indicated that NO within the PVN, but not in systemic circulation, may play a role on the attenuation of the pressor responses elicited by SS. The dysfunction of NO release within the PVN may, in part, play a role in the exaggerated pressor responses in acute environmental stress.

In situ polymerization into porous ceramics: a novel route to tough biomimetic materials

A hydroxyapatite-based biomimetic composite, which is henceforth referred to as a synthetic bony material with high toughness characteristics, was prepared. It was obtained from a hydroxyapatite (HAp) skeleton with a relative porosity fraction of approximately 32 vol %, prepared by cold-isostatic-press compaction, followed by a sintering process, leading to a hydroxyapatite structure containing percolated submicrometer porosity channels. The percolated pores were infiltrated with a liquid mixture of epsilon-caprolactam monomer and an initiator, before homogeneous in situ polymerization to 6-nylon within the fully percolated pore structure was induced thermally. The final composite consisted of a dense interpenetrated hydroxyapatite/6-nylon network in a fraction approximately 68/30 vol %. The work of fracture value of the hybrid composite was found to be comparable with those found in two natural materials (bovine femur and nacre), which were also investigated under the same testing conditions.

Role of the mitochondrial permeability transition and cytochrome C release in hydrogen peroxide-induced apoptosis

We investigated the role of the mitochondrial inner membrane permeability transition and subsequent release of cytochrome c into the cytosol during oxidative stress-evoked apoptosis. Sublethal oxidative stress was applied by treating L929 cells with 0.5 mM H2O2 for 90 min. Then the cellular localization of cytochrome c was examined by immunofluorescent staining and Western blotting. H2O2 treatment caused the permeability transition and pore formation, resulting in membrane depolarization and translocation of cytochrome c from the mitochondria into the cytosol. Pretreatment with cyclosporin A and aristolochic acid (to inhibit pore formation) significantly attenuated a reduction of the mitochondrial membrane potential, as well as signs of apoptosis such as DNA fragmentation, increased plasma membrane permeability, and chromatin condensation. Therefore, exposure to H2O2 caused the opening of permeability transition pores in the inner mitochondrial membrane. An essential role of cytosolic cytochrome c in the execution of apoptosis was demonstrated by its direct microinjection into the cytosol, thus bypassing the need for cytochrome c release from the mitochondrial intermembrane space. Microinjection of cytochrome c caused caspase-dependent apoptosis.

Significantly rapid relief from steroid-resistant nephrotic syndrome by LDL apheresis compared with steroid monotherapy

Rapid amelioration of hypercholesterolemia by LDL apheresis (LDL-A) was performed for long-standing nephrotic syndrome (NS) with hyperlipidemia due to focal segmental glomerulosclerosis (FGS) and the clinical data and prognosis were compared between LDL-A-treated and nontreated groups. Seventeen steroid-resistant NS patients treated with LDL-A (LDL-A group) and 10 NS patients treated with steroids only (steroid-monotherapy (SM) group) were compared. Serum cholesterol and phospholipid levels were significantly lowered only in the LDL-A group (p < 0.01, respectively). The LDL-A group showed a significant decrease of urinary protein (UP, p < 0.01) and increase of serum albumin (p < 0.05). Average time needed to achieve a decrease of UP to less than nephrotic range (< 3.5 g/day) was significantly shorter in the LDL-A group than in the SM group (p < 0.01). Although this is not a prospective study, it is highly expected that a rapid improvement of hypercholesterolemia by LDL-A in steroid-resistant NS will provide more rapid relief from NS than steroid therapy alone.

Antinociceptive effect of the novel compound OT-7100 in a diabetic neuropathy model

We previously reported that OT-7100 (5-n-butyl-7-(3,4,5-trimethoxybenzoylamino)pyrazolo[1,5-alpha]pyrimidine) had antinociceptive potency in various animal models. To further characterize this compound, the present study examined the effects of OT-7100 on mechanical hyperalgesia and motor nerve conduction velocity in streptozotocin-induced diabetic rats. OT-7100 significantly increased the nociceptive threshold in the diabetic rat in a dose-dependent manner. Gabapentin (anticonvulsant agent) and insulin strongly increased the nociceptive threshold but gabapentin increased it above normal levels. An aldose reductase inhibitor slightly increased the nociceptive threshold at a high dose. We also measured glucose levels and motor nerve conduction velocity in OT-7100-treated rats. Insulin decreased glucose levels but OT-7100 had no effect on glucose levels or on motor nerve conduction velocity. These results suggest that OT-7100 alleviates hyperalgesia in a diabetic neuropathy model in a different manner from gabapentin or aldose reductase inhibitor and may be a new treatment for the pain associated with peripheral nerve injury.

A novel analgesic compound OT-7100 attenuates nociceptive responses in animal models of inflammatory and neuropathic hyperalgesia: a possible involvement of adenosinergic anti-nociception

We studied the effects of OT-7100 (5-n-butyl-7-(3,4,5-trimethoxybenzoylamino)pyrazolo [1,5-a]pyrimidine), a novel analgesic compound, on the inhibitory action of adenosine on the contraction of guinea pig ileum and investigated the effects of OT-7100 on the nociceptive responses in animal models of inflammatory and peripheral neuropathic hyperalgesia and decreases spinal c-Fos expression. OT-7100 at 0.3 - 3 microM significantly enhanced the inhibitory effect of adenosine on the contraction of guinea pig ileum. The efficacy of OT-7100 (1, 3 or 10 mg/kg, p.o.) on hyperalgesia induced by yeast or substance P and in the Bennett model was significantly suppressed by coadministration of the adenosine A1 antagonist DPCPX (0.01 or 0.1 pmol/animal, i.t.), while OT-7100 without DPCPX significantly increased the nociceptive threshold in each rat model. OT-7100 (3, 10 and 30 mg/kg per day, p.o.) significantly inhibited the mechanical nociceptive threshold in the injured paw in the Chung model. OT-7100 (30 mg/kg, p.o.) significantly decreased the number of Fos-LI neurons in the spinal dorsal horn in the Bennett model. These finding suggest that OT-7100 inhibits hyperalgesia in these animal models possibly by enhancing adenosinergic neurotransmission in the dorsal horn, although we still lack direct evidence for it.

Immunoassay for human serum albumin using capillary electrophoresis-semiconductor laser-induced fluorometry

Capillary electrophoresis combined with semiconductor laser-induced fluorometry was applied to an immunoassay of human serum albumin. Human serum albumin was labeled with a fluorescent molecule (Cy5), which has an absorption maximum at 649 nm. The labeled albumin was purified by ultrafiltration in order to reduce signals, which are unreacted labeling reagent, product, and fragment products derived there from. After the purification, no signal for unreacted labeling reagent and fragment products was detectable in the electropherogram of the labeled albumin. The labeled albumin was then reacted with anti-albumin to form an immunocomplex, which was separated from the excess free albumin. The competitive immunoassay was used in the determination of human serum albumin in a controlled serum sample, using the labeled albumin. The obtained value was found to be 0.21 +/- 0.02 mg/ml, which is in good agreement with other known values.

A single amino acid change at Leu-188 in the reverse transcriptase of HIV-2 and SIV renders them sensitive to non-nucleoside reverse transcriptase inhibitors

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are selective for human immunodeficiency virus type 1 (HIV-1) and generally not effective on HIV-2 or simian immunodeficiency virus (SIV). Only SIVagm was found to be sensitive to NNRTIs. When the amino acid differences in RT between SIVmac and SIVagm were compared with the known amino acid substitutions of NNRTI-resistance variants of HIV-1, we came to consider that the amino acid residue Leu-188 of HIV-2 and SIVmac might be related to their resistance to NNRTIs. To test this hypothesis, we substituted Leu-188 to Cys or Tyr in HIV-2 and SIVmac, and examined sensitivity of the mutant molecular clones to NNRTIs. The L188Y mutant of HIV-2 became completely sensitive to delavirdine and efavirenz, while that of SIVmac was also significantly sensitive to these NNRTIs. We further isolated NNRTI-resistant variants from these mutant viruses and determined amino acid substitutions in RT. The roles of the observed substitutions in NNRTI-resistance were further confirmed by site-directed mutagenesis. Our study reveals the crucial role of L188 in the natural resistance of HIV-2 and SIVmac to NNRTIs. Furthermore, the observed substitutions in RT of HIV-2 and SIVmac support the common mechanism of action of NNRTIs against HIV-1, HIV-2 and SIV.

Specific labeling of the bovine heart mitochondrial phosphate carrier with fluorescein 5-isothiocyanate: roles of Lys185 and putative adenine nucleotide recognition site in phosphate transport

The amine/SH-modifying fluorescein 5-isothiocyanate (FITC) specifically labeled Lys(185) in the putative membrane-spanning region of the phosphate carrier from both the cytosolic and matrix sides of bovine heart mitochondria at 0 degrees C and pH 7.2, and the labeling inhibited the phosphate transport. Nonmodifying fluorescein derivatives having similar structural features to those of ADP and ATP (Majima, E., Yamaguchi, N., Chuman, H., Shinohara, Y., Ishida, M., Goto, S., and Terada, H. (1998) Biochemistry 37, 424-432) inhibited the specific FITC labeling and phosphate transport, but the nonfluorescein phenylisothiocyanate did not inhibit FITC labeling, suggesting that there is a region recognizing the adenine nucleotides in the phosphate carrier and that this region is closely associated with the transport activity. The phosphate transport inhibitor pyridoxal 5'-phosphate inhibited the specific FITC labeling, possibly due to competitive modification of Lys(185). In addition, FITC inhibited the ADP transport and specific labeling of the ADP/ATP carrier with the fluorescein SH reagent eosin 5-maleimide. Based on these results, we discuss the structural features of the phosphate carrier in relation to its transport activity.

Isolation and characterization of simian immunodeficiency virus variants that are resistant to nonnucleoside reverse transcriptase inhibitors

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) act quite specifically on human immunodeficiency virus type 1 (HIV-1). In general, they are not effective on human immunodeficiency virus type 2 (HIV-2) or simian immunodeficiency virus (SIV). Only SIV strains from African green monkeys are sensitive to several NNRTIs. Here we isolated NNRTI- and 3TC-resistant SIVagm variants. Viruses resistant to delavirdine contained V112I and M231I substitutions, while those resistant to 3TC contained a M 185I substitution. These amino acids are highly conserved in HIV-1, HIV-2, SIVmac and SIVagm, and the M184I (M185I in SIVagm) substitution was observed in 3TC-resistant HIV-1 and SIVmac. The roles of the observed mutations in NNRTI-resistance of SIVagm and HIV-1 were further confirmed by site-directed mutagenesis. The present results have provided a new insight into the common mechanism of sensitivity of HIV- 1 and SIVagm to NNRTIs.

Reduction of atherosclerosis despite hypercholesterolemia in lyn-deficient mice fed a high-fat diet

Oxidation and other modifications of serum low-density lipoprotein (LDL) are associated with the development of atherosclerosis, and a scavenger receptor and CD40 signalling are also known to play important roles in the process. We previously showed that the Src family protein-tyrosine kinase Lyn is physically and/or functionally associated with macrophage type-I and type-II class-A scavenger receptors (MSR-A) and CD40. In this study, we addressed whether Lyn is involved in the build-up of serum lipid levels and in atherosclerotic changes. When fed a normal diet, lyn-deficient mice had serum lipid levels that were no different from those of wild-type mice. By contrast, lyn-deficient mice fed a high-fat diet showed serum lipid levels that were much higher than those seen in wild-type mice. Curiously, however, the lyn-deficient mice fed either diet showed no increase in incidence of atherosclerotic lesions compared with wild-type mice. This may be partly explained by our data showing suppression of proliferation of peritoneal macrophages in response to oxidized LDL in the absence of Lyn, and failure of stimulation of the CD40 pathway in lyn-deficient macrophages to induce expression of monocytic chemoattractant protein-1 (MCP-1), which is related to atherosclerosis. These results suggest that Lyn plays an important role in the metabolism of serum lipids and in the development of atherosclerotic lesions on high-fat diets.

Nitric oxide is an excitatory modulator in the rostral ventrolateral medulla in rats

Nitric oxide is a messenger molecule having various functions in the brain. Previous studies have reported conflicting results for the roles of nitric oxide in the rostral ventrolateral medulla, a major center that regulates sympathetic and cardiovascular activities. We hypothesized that in this region, nitric oxide may have a biphasic effect on cardiovascular activity. Microinjection of a low dose (1 nmol) of a nitric oxide donor sodium nitroprusside or a cyclic GMP agonist 8-bromocyclic GMP into this area increased arterial pressure, whereas injection of a nitric oxide synthase inhibitor Nomega-nitro-L-arginine methyl ester or a soluble guanylate cyclase inhibitor methylene blue decreased arterial pressure. Microinjection of a high dose (100 nmol) of sodium nitroprusside decreased arterial pressure and inhibited spontaneous respiration with concomitant production of peroxynitrite, a strong cytotoxic oxidant. Increases in arterial pressure caused by microinjection of L-glutamate were inhibited after preinjection of Nomega-nitro-L-arginine methyl ester or methylene blue. Increases in arterial pressure caused by microinjection of sodium nitroprusside (1 nmol) were inhibited after preinjection of a glutamate receptor antagonist kynurenate. These results suggest that low doses of nitric oxide may increase arterial pressure, whereas high doses of nitric oxide may decrease arterial pressure through cytotoxic effects in the rostral ventrolateral medulla. They also indicate that nitric oxide may stimulate neurons both through activation of the nitric oxide cyclic GMP pathway and through modulation of glutamate receptor stimulation, and therefore, increase arterial pressure in rats.

Pressor response to pulsatile compression of the rostral ventrolateral medulla mediated by nitric oxide and c-fos expression

It has been reported that neurovascular compression of the rostral ventrolateral medulla might be causally related to essential hypertension. Recently, we found that pulsatile compression of the rostral ventrolateral medulla increases sympathetic nerve activity and elevates arterial pressure via activation of glutamate receptors in rats. We also found that increases in sympathetic and cardiovascular activities by microinjection of L-glutamate into the rostral ventrolateral medulla are mediated by c-fos expression-related substance(s) following activation of the nitric oxide-cyclic GMP pathway. Herein, we investigated whether responses to pulsatile compression are mediated by local activation of the nitric oxide-cyclic GMP pathway and/or c-fos expression-related substance(s) in rats. Increases in arterial pressure (15+/-1 mmHg), heart rate (9+/-1 b.p.m.), and sympathetic nerve activity (% change: 8.5+/-1.1%) induced by pulsatile compression were partially but significantly inhibited after local microinjection of a nitric oxide synthase inhibitor, L-N(G)-nitroarginine methyl ester (8+/-2 mmHg, 1+/-1 b.p.m., 4.0+/-1.3%; P<0.05 vs compression without pretreatment) or 7-nitroindazole (7+/-2 mmHg, 2+/-1 b.p.m., 4.0+/-1. 5%; P<0.05), or a soluble guanylate cyclase inhibitor, methylene blue (9+/-1 mmHg, 4+/-1 b.p.m., 4.1+/-1.4%; P<0.05). In addition, increases in arterial pressure, heart rate, and sympathetic nerve activity by pulsatile compression were significantly reduced 6 h after microinjection of antisense oligodeoxynucleotide to c-fos mRNA (2+/-2 mmHg, 2+/-1 b.p.m., 1.0+/-1.0%; P<0.05 vs sense oligodeoxynucleotide). These results suggest that increases in sympathetic and cardiovascular activities induced by pulsatile compression of the rostral ventrolateral medulla are mediated, at least in part, by local activation of the nitric oxide-cyclic GMP pathway and c-fos expression-related substance(s) in rats.

Effect of long-term cholesterol-lowering treatment with HMG-CoA reductase inhibitor (simvastatin) on myocardial perfusion evaluated by thallium-201 single photon emission computed tomography

Fifteen patients with either angina pectoris or old myocardial infarction, who had positive 201Tl single photon emission computed tomography (SPECT) imaging and coronary sclerosis of more than 50%, were treated with an HMG-CoA reductase inhibitor (simvastatin) for more than 1 year. They were compared with an untreated control group (n = 25). Total cholesterol decreased 22% and high-density lipoprotein (HDL) increased 9% with simvastatin; both changes were significantly different from those in controls. Long-term simvastatin induced improvement of myocardial perfusion on 201Tl SPECT images both during exercise and at rest, which was also significantly different from controls. In addition, the improvement of myocardial perfusion on 201Tl SPECT images was clearly related to the improvements in cholesterol values, especially nonHDL cholesterol. Thus, the greater the decrease in nonHDL cholesterol, the greater the improvement in myocardial perfusion at rest or during exercise with long-term treatment using an HMG-CoA reductase inhibitor. These findings indicate that the improvements in cholesterol values caused by HMG-CoA reductase inhibitor therapy are related to improvements of myocardial perfusion seen on 201Tl SPECT images.

Sensitive detection of myocardial contraction abnormality in chronic hemodialysis patients by ultrasonic tissue characterization with integrated backscatter

Since acoustic properties of the myocardium are sensitive to the myocardial structure and the contractile conditions of myocyte, the authors evaluated cardiac dysfunction based on the integrated ultrasonic backscatter in 18 hemodialysis (HD) patients (duration: 102 +/- 84 months, mean age: 57.6 +/- 9.7 years) and 11 age-matched normals. The cyclic variation of integrated backscatter (CV-IB) at interventricular septum (IVS) and left ventricular posterior wall (PW) was measured and compared with percent fractional shortening (%FS) and percent wall thickening (%Th). The CV-IB of HD patients was smaller than that of control subjects (IVS: 6.2 +/- 1.1 dB vs 8.2 +/- 1.1 dB, p = 0.0003 and PW: 8.4 +/- 2.2 vs 10.3 +/- 1.3, p= 0.025). No significant difference was observed in %FS and %Th between HD patients and control subjects. In HD, the ratio of velocities of early diastolic inflow (E) to late atrial inflow was decreased (0.7 +/- 0.2 vs 1.1 +/- 0.7, p = 0.049) and deceleration time of E was prolonged significantly (200 +/- 28 msec vs 159 +/- 30 msec, p = 0.0082). In the absence of overt cardiac systolic dysfunction, myocardial damage indicated as a decrease in CV-IB and diastolic dysfunction identified on transmitral velocity waveform were detected, which may reflect from the myocardial fibrosis. As a mechanism, pressure overload, hyperparathyroidism, and anemia were neglected, and the other humoral factors may contribute to the myocardial damage in chronic renal failure.

Modulation of endothelin-1 coronary vasoconstriction in spontaneously hypertensive rats by the nitric oxide system

To determine whether nitric oxide contributes to the augmented vasoconstrictive response to endothelin-1 (ET-1) in coronary vessels of hypertensive hearts, and also whether L-arginine administration can inhibit the augmented response to ET-1, we designed experiments to measure coronary perfusion resistance in isolated hearts of spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) with or without L-arginine administration (0.5 g/L) for 2 weeks. The hearts were paced at a constant rate and perfused by the Langendorff technique at constant pressure (75 mm Hg). Perfusion flow and pressure were monitored, and coronary vascular resistance (CVR) was calculated. ET-1 infusion elicited dose-dependent increases in CVR in both WKY and SHR. At an ET-1 concentration of 1.5 x 10(-9) mol/L, the response was significantly greater in SHR. In L-NAME-treated WKY and SHR, responses to ET-1 were augmented, compared with those of nontreated rats, and this augmentation was greater in WKY. L-arginine administration reduced the CVR response to ET-1 in SHR, whereas it did not change responses to ET-1 in WKY. These findings suggest that the augmented vasoconstriction of the coronary artery induced by ET-1 in hypertensive hearts was due to a reduction in nitric oxide release in coronary vessels and that L-arginine can partially inhibit the vasoconstrictive response of the coronary artery.

Sodium sensitivity and sympathetic nervous system in hypertension induced by long-term nitric oxide blockade in rats

1. Pharmacological inhibition of nitric oxide (NO) synthesis is known to produce acute and chronic hypertension in many animal species, but the underlying mechanisms mediating the hypertension are not completely understood. In particular, the pathogenetic roles of sodium sensitivity and the sympathetic nervous system in this model of hypertension are controversial. The present study was designed to test the hypothesis that long-term administration of the NO synthesis inhibitor NG-nitro-L-arginine methyl ester (L-NAME) to male Sprague-Dawley rats would produce a sodium-sensitive hypertension and that the enhanced activity of the sympathetic nervous system in this type of hypertension contributes to the sodium sensitivity. 2. NG-Nitro-L-arginine methyl ester was added to drinking fluid for 8 weeks at a concentration of 16 mg/dL. Rats received tap water for the first 4 weeks of the study and were then divided into two groups and placed on either a normal or high sodium intake (ingestion of either tap water or 0.9% NaCl, respectively). Awake systolic blood pressure was measured by the tail-cuff method every week. Urinary excretion rates of the stable NO metabolites and catecholamines during NO synthesis inhibition were examined. 3. Long-term administration of L-NAME produced a marked and sustained elevation in arterial pressure without altering urine flow, or sodium excretion rate. NG-Nitro-L-arginine methyl ester-induced hypertension was accompanied by a decreased urinary excretion of the stable NO metabolites NO2- and NO3- and was aggravated when rats drank 0.9% NaCl in place of tap water. Urinary excretion of adrenaline and noradrenaline, but not dopamine, in L-NAME-treated rats increased significantly within the first week of the study compared with control rats. L-Arginine (2 g/dL in drinking fluid) completely reversed the elevation of arterial pressure as well as the decrease in urinary NO2- and NO3- excretion and the increased urinary excretion of catecholamines associated with L-NAME treatment by 3 weeks of concomitant administration. 4. These results suggest that long-term inhibition of NO synthesis produces a sodium-sensitive hypertension and that changes in sympathetic nerve activity may, at least in part, contribute to the sodium sensitivity in this type of hypertension.

Enhanced HIV-1 replication by chemokines constitutively expressed in secondary lymphoid tissues

Persistent infection of human immunodeficiency virus (HIV) takes place in the secondary lymphoid tissues even during clinically latent stages. The CC chemokines secondary lymphoid tissue chemokine (SLC) and EBI1-ligand chemokine (ELC) are constitutively expressed in the secondary lymphoid tissues. They share CCR7 expressed on lymphocytes and mature dendritic cells and play key roles in the trafficking of these types of cells into the secondary lymphoid tissues. Here we report that growth of both X4 and R5 strains of HIV-1 in activated peripheral blood T cells was enhanced by SLC. The enhancing effect of SLC was abrogated by pretreatment of cells with pertussis toxin, indicating the involvement of signaling via a receptor coupled with a Galphai class of G-protein. Furthermore, SLC was found to enhance the promoter activity of HIV-1 LTR. These results suggest that signaling via CCR7 has a strong positive effect on HIV growth. Thus, SLC and ELC may contribute to persistent infection of HIV in the secondary lymphoid tissues by promoting viral replication in activated T cells.

Small amino acid changes in the V3 loop of human immunodeficiency virus type 2 determines the coreceptor usage for CXCR4 and CCR5

HIV-2 GH-1 is a molecular clone derived from an AIDS patient from Ghana. In contrast to the prototypic molecular clone ROD, GH-1 exhibits a narrow range of target cell specificity. By an infectious assay using HeLa-CD4 cells stably transfected with an HIV-1 LTR-beta-galactosidase reporter gene and transiently expressing various cloned chemokine receptors, we have examined the coreceptor usage of GH-1. In contrast to ROD, which uses principally CXCR4, GH-1 was found to use mainly if not exclusively CCR5 but not CXCR4. The distinct coreceptor usage of these two molecular clones allowed us to further map the region of gp120 that is important for the coreceptor specificity. By constructing a series of chimeric viruses between GH-1 and ROD, we have demonstrated that the C-terminal half of the V3 loop region of gp120 determines the differential coreceptor usage between GH-1 and ROD, and only a few amino acid differences in this region appear to be able to shift the specificity between CCR5 and CXCR4. Notably, the shift in the coreceptor usage from CCR5 to CXCR4 is associated with an increase in the net positive charge in the V3 region.

Distance between mitral anulus and papillary muscles: anatomic study in normal human hearts

BACKGROUND

Preservation of the annulo-papillary muscle continuity in mitral valve replacement is important. Even in patients who require excision of the mitral apparatus, the continuity can be restored. However, there is no guide to the proper length for the resuspension.

METHODS

In 57 normal cadaveric hearts, the distance from the tip of the papillary muscle to its corresponding mitral anulus was directly measured.

RESULTS

The distance from the tip of the anterolateral papillary muscle to the left trigone (10-o'clock position: D10) and to the point between the anterior and the middle scallops of the mural leaflet (8-o'clock position: D8) was 23.5 +/- 3.7 mm and 23.2 +/- 3.6 mm, respectively. The distance from the tip of the posteromedial papillary muscle to the right trigone (2-o'clock position: D2) and to the point between the middle and the posterior scallops of the mural leaflet (4-o'clock position: D4) was 23.5 +/- 4.0 mm and 23.5 +/- 3.9 mm, respectively. There was no statistically significant difference among the 4 distances (P =.96). Each distance was significantly longer than the corresponding chordae tendineae (D10 vs the anterior main chorda: 17.2 +/- 3.9 mm, D8 vs the anterior cleft chorda: 14.5 +/- 3.2 mm, D2 vs the posterior main chorda: 17.9 +/- 4.3 mm, and D4 vs the posterior cleft chorda: 14.9 +/- 3.2 mm, respectively; P =.0001). The mean distance had a significant correlation with the mitral annular diameter (r = 0.31, P =.019).

CONCLUSIONS

In normal hearts, the annulo-papillary muscle distances of the mitral apparatus are similar in 2-, 4-, 8-, and 10-o'clock positions and correlate with the mitral annular diameter.