Annual improvement trends in resuscitation outcome of patients defibrillated by laypersons after out-of-hospital cardiac arrests and compression-only resuscitation of laypersons

AIM

We aimed to investigate the effect of compression-only cardiopulmonary resuscitation (CPR) with conventional CPR in patients who were defibrillated by laypersons.

METHODS

This is a population-based, nationwide observational study. Adult and children who sustained a witnessed out-of-hospital cardiac arrest and defibrillated by laypersons between 2005 to 2019 were identified on the national database. The study used trend analyses, multivariate logistic regression, and inverse probability weighting using propensity score to explore changes in one-month survival and survival with a good neurological outcome over time and the influence of compression-only CPR compared with conventional CPR.

RESULTS

In total, 11,402 patients defibrillated by laypersons were enrolled in this study. The percentages of compression-only resuscitation increased dramatically and more than 50% from 2012 (P < 0.001). The percentages of cases with favorable resuscitation outcomes also increased annually (P < 0.001). By regression analysis, favorable outcomes were associated with recent years, male sex, younger age, and shorter resuscitation start time. In addition, the adjusted odds ratio of compression-only CPR to conventional CPR was 1.23 with a 95% confident interval 1.13-1.34. By inverse probability weighting, compression-only CPR was superior to conventional CPR for the favorable outcomes (P < 0.001). The adjusted outcomes in each year were better in compression-only resuscitation in most of the years. The overall relative risk reduction and the number needed to treat for compression-only resuscitation compared with conventional resuscitation were 7.6% and 22.1, respectively.

CONCLUSIONS

In Japan, the outcomes of out-of-hospital cardiac arrest patients who were defibrillated by laypersons were considerably better in compression-only resuscitation of laypersons every year.

The vascular response to ultrathin biodegradable polymer sirolimus-eluting stent at 2-weeks and 1-year follow up in patients with ST-elevation myocardial infarction

Background

Recent clinical study suggests newer-generation drug-eluting stents (DES) that combine ultrathin strut and nano-coating with biodegradable polymers sirolimus-eluting stent (BP-SES) could improve long-term clinical outcomes in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) over current generation DES. However, the details of vascular response in very early and chronic phase have not been systematically addressed.

Objective and method

We exploratory investigate early and chronic vascular response following BP-SES implantation in patients with STEMI to reveal mechanism of the favorable clinical outcomes in recent studies using frequency domain-optical coherence tomography (FD-OCT).

Consecutive twenty-four patients with STEMI who underwent FD-OCT after primary PCI and were eligible for follow-up FD-OCT at 2 weeks and 1 year after implantation were enrolled between June 2018 and August 2020.

OCT was performed immediately after PCI, at 2-weeks (2W) and 1-year (1Y) after the primary PCI. Struts were recorded as uncovered if any part was visibly exposed in the lumen or covered if a layer of tissue covered all reflecting surfaces. Struts of stents that are smaller than 3.0mm of diameter with more than 80μm between the center reflection and the adjacent vessel surface were recorded as malapposed. The reduction of atherothrombotic protrusion burden within the stent was also assessed.

Results

Twenty-four patients (age 64.9±11.4 years, male 83.3%) were enrolled.

The percentage of uncovered struts significantly decreased from post-PCI to 2W follow-up and from 2W follow-up to 1Y follow-up (62±20% post-PCI versus 27±11% at 2W follow up, p&lt;0.0001 and 2W follow-up versus 3.3±3.3% at 1Y follow up, p&lt;0.0001). Malapposed struts also decreased from post-PCI to 2W follow-up (4.1±3.6% post-PCI versus 1.5±2.2% at 2W follow-up, p&lt;0.0001), but no significant difference was shown between 2W follow-up and 1Y follow-up (2W follow-up versus 1.0±2.3 at 1Y follow up, p=0.12). The average protrusion area of athero-thrombotic burden decreased (0.57±0.32 at post-PCI versus 0.42±0.22 mm2 at 2W follow up, p&lt;0.0001) and its volume showed similar tendency (16.6±10.7 at post-PCI versus 12.9±8.23 mm3 at 2W follow up, p=0.0011). Thrombus was shown in all patients at post-PCI, but two patients (8.0%) showed it at 1Y follow-up.

Conclusion(s)

This study elucidated very early and chronic vascular responses following ultrathin strut BP-SES implantation in STEMI patients by FD-OCT. It showed resolution of athero-thrombotic materials in very early phase and favorable progression of strut coverage in very early and chronic phase.

Funding Acknowledgement

Type of funding sources: None.

Altered consciousness with transient abnormal signals in the hippocampus: A case report

Hippocampal infarction is relatively rare. Many different diseases can mimic hippocampal infarction including transient global amnesia, Alzheimer’s disease, epilepsy, encephalitis, and encephalopathies. An 89-year-old man was transported to our hospital for altered consciousness. Diffusion-weighted magnetic resonance imaging revealed slightly intense signals in the hippocampus with a mildly decreased apparent diffusion coefficient. Serial magnetic resonance imaging revealed features of hippocampal infarction. Symptoms and cognitive function gradually improved with rehabilitation, and he was transferred to a rehabilitation facility on Hospital Day 38. Hippocampal infarction is rare in patients with altered mental status, but should be considered when magnetic resonance imaging shows findings suggestive of this condition. Other differential diseases should be ruled out by serial magnetic resonance imaging and observation of the clinical course.

Contributions of small dense LDL and oxidized LDL on the formation of neoatherosclerosis in patients under statin treatment

Aim

In-stent neoatherosclerosis (NA) has emerged as an important contributing factor to late stent failure and cardiovascular events. The aim of this study was to investigate whether lipid markers are associated with NA using optical coherence tomography (OCT) after percutaneous coronary intervention (PCI) in patients with coronary artery disease under well-controlled low density lipoprotein cholesterol (LDL-c) on statin treatment.

Methods

We enrolled consecutive 115 patients under statin treatment who underwent PCI with current-generation drug-eluting stent for acute and chronic coronary syndrome. OCT image and various lipid markers were obtained at 1-year for scheduled research assessment. NA was defined as a lipid laden neointima or calcified neointima. Both small dense LDL-c (sd-LDL-c) and remnant lipoprotein cholesterol (RL-c) were measured using direct homogenous assay.

Results

During an average follow-up of 13 months, NA was observed in 14 (13.6%) patients. Not LDL-c but sd-LDL-c, Malondialdehyde-modified LDL (MDA-LDL) as oxidized LDL and (RL-c) were significantly higher in patients with NA. The optimal threshold values of sd-LDL-c, MDA-LDL and RL-c for predicting NA according to receiver operating characteristics analysis were 32.3 mg/dl, 91.0 U/L, and 3.3 mg/dL, respectively. On multivariate logistic regression analysis, sd-LDL-c (≥32.3 mg/dL) and MDA (≥91.0 U/L) were significantly associated with NA (odds ratio [OR]:13.62, p=0.016, OR: 12.68, p=0.01, respectively).

Conclusions

In statin-treated patients, sd-LDL-c and MDA-LDL but not LDL-c might be useful biomarkers to identify the formation of NA at 1 years after PCI. Aggressive reduction of these atherogenic LDL may have a potential to prevent the formation of NA.

Funding Acknowledgement

Type of funding sources: None.

Higher plasma level of small dense low-density lipoprotein cholesterol in ST-segment-elevation myocardial infarction patients with plaque rupture

Aim

The aim of this study was to compare small dense low-density lipoprotein cholesterol (sd-LDL-c) and various lipid markers between patients exhibiting plaque rupture (PR) in the culprit lesions evaluated by optical coherence tomography (OCT) imaging and those without PR in ST-segment elevation myocardial infarction (STEMI) patients.

Methods

We studied consecutive 60 de novo culprit lesions in 60 patients with STEMI who underwent pre-intervention OCT. PR was defined as a plaque containing a cavity that had overlying residual fibrous caps. Plasma sd-LDL-c was measured directly by homogeneous assay at the time of primary percutaneous coronary intervention.

Results

The patients were classified into PR (n=40, 66.7%) or non-PR (n=20, 33.3%). There were no significant differences in low-density lipoprotein cholesterol (LDL-c), non-high-density lipoprotein cholesterol (non-HDL-c) and pre-admission statin therapy between two groups (135.1±38.0 mg/dL vs 129.2±43.8 mg/dL; p=0.35, 157.1±37.4 mg/dL vs 143.0±37.7 mg/dL; p=0.24, 15.0% vs 20.0%; p=0.93). However, sd-LDL-c level was significantly higher in patients with PR than those with non-PR (44.0±18.1 mg/dL vs 28.0±9.3 mg/dL; p=0.0005). On multiple logistic regression analysis, sd-LDL-c was an independent predictor of PR (odds ratio, 1.14 per 1 mg/dL; p=0.0063).

Conclusion

Sd-LDL-c was significantly associated with PR of the culprit lesion in patients with STEMI.

Funding Acknowledgement

Type of funding sources: None.

Early vascular healing following bioresorbable-polymer sirolimus-eluting stent implantation in comparison with durable-polymer everolimus-eluting stent: sequential optical coherence tomography study

Background

Orsiro ultrathin-strut bioresorbable-polymer sirolimus-eluting stent (BP-SES) might facilitate early vascular healing responses that seems to be associated with improved long-term clinical outcomes. We compared the early vascular healing responses to BP-SES and Xience durable-polymer everolimus-eluting stent (DP-EES) in patients with chronic coronary syndrome (CCS) using optical coherence tomography (OCT).

Methods

A total of 40 patients with CCS receiving OCT-guided PCI were included. 20 patients were assigned to BP-SES, and 20 to DP-EES. OCT was performed immediately after stent placement (post-procedure) and at 1 month follow-up. Struts were recorded as uncovered if any part was visibly exposed in the lumen or covered if a layer of tissue covered all reflecting surfaces. The incidence of intrastent thrombus (IS-Th) and irregular protrusion (IRP) were also assessed.

Results

At 1 month, the percentage of uncovered struts was significantly lower in the BP-SES compared with the DP-EES (2.8±1.6% vs. 5.8±1.8%, respectively; p&lt;0.001), and that of malapposed struts was similar between both groups (2.5±3.1% vs. 2.4±2.2%; p=0.76). There were no differences in the incidence of IS-Th (65.0% vs. 55.0% at post-procedure; p=0.54, 30.0% vs. 35.0% at 1 month; p=0.75) and IRP (30.0% vs. 25.0% at post-procedure; p=0.74). IRP had completely resolved at 1 month in both groups.

Conclusion

Early vascular healing response to Orsiro BP-SES implantation was revealed in CCS patients at 1 month compared with Xience DP-EES. Orsiro BP-SES may have a potential to shorten the dual antiplatelet therapy duration.

Funding Acknowledgement

Type of funding source: None

Early vascular responses to ultrathin biodegradable polymer sirolimus-eluting stent for the treatment of st-elevation myocardial infarction

Background

Recent clinical study suggests newer-generation drug-eluting stents (DES) that combine ultrathin strut and nano-coating with biodegradable polymers sirolimus-eluting stent (BP-SES) could improve long-term clinical outcomes in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) over current generation DES. However, safety profiles in very early phase have not been systematically addressed.

Objective and method

We exploratory investigate early vascular response following BP-SES implantation in patients with STEMI to reveal mechanism of the favorable clinical outcomes in recent studies using frequency domain-optical coherence tomography (FD-OCT).

Consecutive twenty patients with STEMI who underwent FD-OCT immediately after primary PCI and were eligible for follow-up FD-OCT at 2 weeks after implantation were enrolled between June 2018 and November 2019.

Results

Twenty patients (age 62.7±11.3 years, male 85.0%) were enrolled with frequencies of hypertension (45.0%), diabetes mellitus (35.0%), dyslipidemia (55.0%) and smoking (80.0%). Aspiration catheter were used in all patients, and 1.13±0.34 stents were used. Only one patient (5.0%) received chronic antiplatelet therapy with aspirin prior to the onset of STEMI. All patients started to receive prasugrel as thienopyridine from this event and continued dual antiplatelet therapy for 2 weeks.

The percentage of uncovered struts significantly decreased from post-procedure to 2W follow-up (69±18% post-procedure versus 30±11% at 2W follow up, p&lt;0.0001). Malapposed struts also decreased (5.6±5.7% post-procedure versus0.9±1.2% at 2W follow up, p&lt;0.0001).The average protrusion area of athero-thrombotic burden numerically decreased (0.37±0.19 at post-procedure versus 0.34±0.14 mm2 at 2W follow up, p=0.19) and its volume showed similar tendency (10.60±6.40 at post-procedure versus 9.36±5.14 mm3 at 2W follow up, p=0.19).

Conclusion(s)

This study firstly elucidated very early vascular responses following ultrathin strut BP-SES implantation in STEMI patients, showing early progression of strut coverage and resolution of athero-thrombotic materials. This technology may have a potential to overcome the current generation DESs in this clinical setting.

Thrombus, uncovered and malapposed struts

Funding Acknowledgement

Type of funding source: None

Tachyarrhythmia improved by management of low back pain in a patient with delayed diagnosis of infective spondylodiscitis: A case report

A 77-year-old man presented to the emergency room with a 1-month history of persistent low back pain with the absence of vital sign abnormalities. On several previous orthopedic surgery clinic visits, pathological back pain had not been considered and pain killers had been prescribed because he had low back pain due to lumbar spinal canal stenosis. He was admitted to the intensive care unit for infectious spondylodiscitis and infective endocarditis with disseminated abscess caused by methicillin-resistant Staphylococcus aureus. Shock refractory tachyarrhythmia could not be managed with antiarrhythmic agent in the intensive care unit. Intractable low back pain and persistent tachyarrhythmia were adequately managed by pain control with fentanyl in the intensive care unit. Infectious spondylodiscitis and infective endocarditis were effectively managed with anti-methicillin-resistant Staphylococcus aureus drugs, initially in rotational usage, but the patient died of extended-spectrum beta-lactamase-producing Escherichia coli pneumonia on day 50 of hospitalization. Infectious spondylodiscitis should have been considered for persistent low back pain with hemodialysis, fever, and a history of device implantation. Pain management may be necessary for persistent tachycardia that proves unresponsive to usual antiarrhythmic medications.

THU0171 EFFICACY OF ABATACEPT FOR SUPPRESSING RADIOGRAPHIC PROGRESSION OF CERVICAL LESIONS IN PATIENTS WITH RHEUMATOID ARTHRITIS COMPARISON WITH METHOTREXATE TREATMENT; TWO YEARS OF FOLLOW-UP ~A MULTICENTER REGISTRY STUDY ~

Background:

Cervical lesions are known to occur at high frequency as a complication of rheumatoid arthritis (RA). Treatment with biological agents are more clinically effective than the DMARDs that were in use previously, in particular, with their efficacy in suppressing joint destruction having been emphasized. We reported the efficacy of infliximab, anti-tumor necrosis factor antibodies for suppressing the radiographic progression of RA cervical lesions at ACR2009, EULAR2010, 11, 12, 13, 14,16 and 18. However there is still few studies of efficacy of against RA cervical lesions of Abatacept (ABT) that inhibits T cell activation by binding to CD80/86.

Objectives:

To evaluate the efficacy of ABT for suppressing the radiographic progression of RA cervical lesions comparison with MTX for 2 years.

Methods:

We used ABT or MTX for treating Japanese patients with active RA who fulfilled the ACR criteria in 1987. The final study cohort of each 60 and 75 patients received continuous ABT and MTX treatment for at least 2 years. For evaluation of cervical lesions, the atlanto-dental interval (ADI), the space available for the spinal cord (SAC), and the Ranawat value were measured by plain lateral radiographs in the flexion position, at initiation and Year 1,2.

Results:

In the patients receiving ABT (n=60) and MTX (n =75), the number of female were each 48(80%) and 52(69%) cases(p=0.160). The mean age was 67.7 ± 12.9 and 63.6 ± 11.0 years old (p=0.004); disease duration was 16.7 ± 14.2 and 8.0 ± 9.5 years (p<0.001) and the mean dose of MTX was 8.4 ± 3.6 and 8.2 ± 2.9 mg/w (p=0.804). Clinical findings related to RA were as follows; CRP 2.2± 2.1 and 1.7± 2.3 mg/dl(p=0.008); ESR 47.2 ± 23.4 and 31.9 ± 21.8mm/h(p<0.001); MMP3 253 ± 280 and 223 ± 350ng/ml(p=0.003); the number of RF-positive 57(95%) and 60(80%) cases(p=0.011); DAS28-ESR 5.13 ± 0.99 and 4.30 ± 1.38 (p<0.001); ADI 3.6 ± 2.1 and 2.6 ± 1.6mm(p=0.003); SAC 18.5 ± 2.8 and 20.8 ± 2.5mm(p<0.001) and Ranawat value 14.4 ± 1.9 and 16.0 ± 1.5mm (p<0.001). The respective changes in cervical lesion parameters after 1 year were as follows: ADI: 0.20 ± 0.40 and 0.27 ± 0.45 mm (p = 0.367); SAC: −0.12 ± 0.32 and −0.17 ± 0.38 mm (p = 0.359); and Ranawat value: −0.15 ± 0.36 and −0.13 ± 0.34 mm (p = 0.783). The respective changes in cervical lesion parameters after 2 years were as follows: ADI: 0.35 ± 0.58 and 0.55 ± 0.70 mm (p = 0.099); SAC: −0.25 ± 0.47 and −0.45 ± 0.62 mm (p = 0.047); and Ranawat value: −0.23 ± 0.47 and −0.33 ± 0.55 mm (p = 0.293) in the patients receiving ABT and MTX (Fig. 1). The numbers of patients who did not showed progression in ADI, SAC and Ranawat value were each 42(70%) and 43(57%) cases(p=0.130); 46(77%) and 46(61%) cases(p=0.057) and 47(78%) and 53(71%) cases(p=0.313) after 2 years. Also the number who was able to suppress progression in all three parameters were each 42 cases (70%) receiving ABT and 43 cases (57%) receiving MTX (p=0.130) after 2 years (Fig. 2).

Conclusion:

This study suggested that ABT treatment can be used to suppress the progression of RA cervical lesions more than MTX treatment.

Disclosure of Interests:

Yasuhide Kanayama: None declared, Toshihisa Kojima Grant/research support from: Chugai, Eli Lilly, Astellas, Abbvie, and Novartis, Consultant of: AbbVie, Speakers bureau: AbbVie, Astellas, Bristol-Myers Squibb, Chugai, Daiichi-Sankyo, Eli Lilly, Janssen, Mitsubishi Tanabe, Pfizer, and Takeda, Yuji Hirano Speakers bureau: Tanabe-Mitsubishi, Pfizer, Eisai, Abbie, Chugai, Bristol-Meyers, Jansen, Astellas, UCB, Eli-Lilly, Asahikasei, Daiichi-Sankyo, Amgen, Nobunori Takahashi Speakers bureau: AbbVie, Asahi Kasei, Astellas, Bristol-Myers Squibb, Chugai, Daiichi-Sankyo, Eisai, Eli Lilly, Janssen, Mitsubishi Tanabe, Ono, Pfizer, Takeda, and UCB Japan, Yukiyoshi Oishi: None declared, Naoki Ishiguro Grant/research support from: AbbVie, Asahi Kasei, Astellas, Chugai, Daiichi-Sankyo, Eisai, Kaken, Mitsubishi Tanabe, Otsuka, Pfizer, Takeda, and Zimmer Biomet, Consultant of: Ono, Speakers bureau: Astellas, Bristol-Myers Squibb, Daiichi-Sankyo, Eli Lilly, Pfizer, and Taisho Toyama

Excellent performance of aromatic polyguanamines induced by multiple hydrogen bondable tetraazacalix[2]arene[2]-triazine ring in their main chain

A series of poly(guanamine) (c-PG)s containing tetraazacalix[2]arene[2]-triazine (mPDA₂CyC₂) were successfully prepared by solution polycondensation of mPDA₂CyC₂ with various aromatic diamines in an aprotic organic solvent with a lithium chloride additive (5 wt%) at 150 °C for 6 hours. The number-average molecular weights (M_n)s of these c-PG polymers reached up to 31 500, with a relatively broad molecular weight distribution (M_w/M_n) of 5.3. They showed good solubility in aprotic organic solvents, such as N-methylpyrrolidone and N,N-dimethylacetamide at a concentration of 2 mg mL⁻¹. The glass transition temperatures (T_g) of the c-PG polymers were in the range 359 °C–392 °C, approximately 160 °C higher than those of counterpart polymers (i.e., with no aza-calixarene-based PG (l-PG)). The coefficients of thermal expansion (CTEs) of the c-PG polymers were 29.7–48.1 ppm K⁻¹ (at 100 °C–150 °C), much lower than those of l-PG samples, i.e., 59.1–85.1 ppm K⁻¹. Transparent and almost colorless c-PG films were successfully prepared by a solution casting method, showing maximum tensile strength (σ_S), modulus (E_γ), and elongation at break (E_b) values of 151 MPa, 6.3 GPa, and 4.4%, respectively, for the c-PG polymer from mPDA₂CyC₂ and 4,4′-oxydianiline monomers. The corresponding l-PG film exhibited σ_S, E_γ, and E_b values of just 76 MPa, 5.4 GPa, and 1.6%, respectively. These outstanding thermal and mechanical properties of the c-PG polymers can be attributed to their multiple hydrogen bonding interaction between mPDA₂CyC₂ residues in the polymer backbone. This interaction was identified by infrared spectroscopy measurements at the broad absorption band around 3000–3400 cm⁻¹.

Poly(guanamine)s containing tetraazacalix[2]arene[2]triazine ring within the polymer main-chain show outstanding thermal and mechanical properties arisen from the multiple-hydrogen bond.

Type A fulminant Clostridium perfringens sepsis indicated RBC/Hb discrepancy; a case report

Background

Clostridium perfringens can cause various infections, including food poisoning, gas gangrene, cellulitis and fasciitis. C. perfringens septicemia is rare, but is a known cause of hemolysis by damaging red blood cell, and often proves rapidly fatal in emergency department (ED) situations.

Case presentation

A previously healthy 76-year-old man presented to the ED 8 h after onset of acute abdominal pain and diarrhea. Laboratory examination revealed a large discrepancy between the red blood cell count of 1.91 × 10⁶/mm³ and the hemoglobin level of 10.3 g/dL, suggesting massive intravascular hemolysis. Computed tomography revealed liver abscesses with gas. During ED treatment, the state of the patient rapidly deteriorated and he entered cardiopulmonary arrest. Blood cultures finally identified C. perfringens.

Conclusion

Intravascular hemolysis and red blood cell (RBC) / hemoglobin (Hb) discrepancy in the presence of infection should prompt ED physicians to consider C. perfringens septicemia and to act quickly to provide appropriate treatment.

Transcatheter arterial embolisation in four dogs with hepatocellular carcinoma

Four dogs with hepatocellular carcinoma were treated by transcatheter arterial embolisation. In all dogs, the tumour-supplying arteries were selectively embolised with gelatine sponge particles. Post-embolisation tumour volumes decreased relative to pre-embolisation volumes in all dogs. No adverse reactions were observed in three dogs after treatment but one dog showed pancreatitis. These results suggest that transcatheter arterial embolisation is a feasible treatment for dogs with hepatocellular carcinoma.

Nickel-Catalyzed Propylene/Polar Monomer Copolymerization

Nickel complexes bearing bidentate alkylphophine-phenolate ligands were synthesized and applied to the polymerization of propylene and the copolymerization of propylene and polar monomers. Therein, the use of bulky alkyl substituents on the phosphorus atom was crucial for the formation of highly regioregular polypropylenes. Theoretical calculations suggested that the 1,2-insertion of propylene is favored over the 2,1-insertion in these nickel-catalyzed (co)polymerization reactions. The substituent at the ortho position relative to the oxido group greatly influences the polymerization activity, the molecular weight, and stereoregularity of the polypropylenes. This method delivers moderately isotactic ([mm] ≤ 68%) crystalline polypropylenes. The present system represents the first example for a nickel-catalyzed regiocontrolled copolymerization of propylene and polar monomers such as but-3-en-1-ol, but-3-en-1-yl acetate, and tert-butyl allylcarbamate.

Rapid synthesis and properties of segmented block copolymers based on monodisperse aromatic poly(N-methyl benzamide) and poly(propylene oxide)

Monodisperse aromatic N-methyl benzamide-based molecules (M_w/M_n = 1.02–1.04) with terephthalic acid at both sides (MABx–x) were rapidly prepared by a step-wise reaction using the reported one-pot dendrimer synthetic method.

Effects of collagen hydrolysate on the tibialis anterior muscle and femur in senescence-accelerated mouse prone 6

OBJECTIVES

Effects of collagen hydrolysate (CHD) on the oxidative capacity of the tibialis anterior muscle and the cortical and trabecular density of the femur were investigated in senescence-accelerated mouse prone 6 (SAMP6).

METHODS

Sixteen-week-old male SAMP6 mice were divided into control (CON) and CHD groups. The CON group was given normal water, while the CHD group was given water containing CHD. Fibre cross-sectional areas (CSAs), fibre succinate dehydrogenase (SDH) staining intensity, and SDH activity of the tibialis anterior muscle were determined at 42 and 60 weeks of age. The cortical and trabecular density of the femur and serum osteocalcin levels were also determined.

RESULTS

The fibre SDH staining intensity and muscle SDH activity were higher in the CHD group at 60 weeks of age than in the age-matched CON group. The cortical and trabecular density and serum osteocalcin levels were greater in the CHD group at 60 weeks of age than in the age-matched CON group.

CONCLUSION

CHD inhibited th age-induced decrease in muscle oxidative capacity and bone density of SAMP6 mice. There is a possibility that CHD is effective for inhibition of age-induced degeneration in the musculoskeletal system.

Synthesis of highly refractive and highly fluorescent rigid cyanuryl polyimines with polycyclic aromatic hydrocarbon pendants

A series of rigid cyanuryl polyimines, polyguanamines (PGs) bearing polycyclic aromatic hydrocarbon pendants were successfully synthesized from 2-substituted 4,6-dichloro-1,3,5-triazine and aromatic diamine monomers.

Source of sex pheromone of the egg-larval parasitoid,Ascogaster reticulatus Watanabe (Hymenoptera: Braconidae)

A sex pheromone ofAscogaster reticulatus Watanabe (Hymenoptera: Braconidae), identified as (Z)-9-hexadecenal, elicits males' antennal matesearching behavior. In order to localize the source of sex pheromone production, each body part was separated and extracted with hexane and then subjected to 9-cm Petri dish bioassay. The highest activity was found in thorax extract. Among legs, wings, and thorax, legs have the highest activity. Among fore, middle, and hind legs, hind legs have the highest activity. Among coxa and trochanter, femur, tibia, and tarsus, tibia has the highest activity. From these results, the presence of a tibial sex pheromone gland was suggested.

Quenching electron runaway in positive high-voltage-impulse discharges in air by laser filaments

Strong hard (ε>100 keV) x rays being observed from impulse atmospheric discharges with maximal voltages from U=0.5 to 0.9 MV just before the breakdown were completely stopped with the use of femtosecond-laser-filament plasma. Runaway electrons generating such x rays and being estimated to achieve their maximal energy, ε~U, near the positive electrode disappear if a laser filament plasma is ignited perpendicularly to the runaway near the positive electrode. A preheating mechanism for formation of the electron runaway in air is proposed.