Latent ion tracks were finally observed in diamond

Injecting high-energy heavy ions in the electronic stopping regime into solids can create cylindrical damage zones called latent ion tracks. Although these tracks form in many materials, none have ever been observed in diamond, even when irradiated with high-energy GeV uranium ions. Here we report the first observation of ion track formation in diamond irradiated with 2-9 MeV C60 fullerene ions. Depending on the ion energy, the mean track length (diameter) changed from 17 (3.2) nm to 52 (7.1) nm. High resolution scanning transmission electron microscopy (HR-STEM) indicated the amorphization in the tracks, in which π-bonding signal from graphite was detected by the electron energy loss spectroscopy (EELS). Since the melting transition is not induced in diamond at atmospheric pressure, conventional inelastic thermal spike calculations cannot be applied. Two-temperature molecular dynamics simulations succeeded in the reproduction of both the track formation under MeV C60 irradiations and the no-track formation under GeV monoatomic ion irradiations.

Verifying the Japanese version of the Healthy Aging Brain Care Monitor self-report tool for evaluating post-intensive care syndrome

BACKGROUND

Post-intensive care syndrome (PICS) requires the use of multiple assessment tools because it affects multiple domains: Cognitive, Functional, and Behavioural/Psychological. Therefore, this study translated the self-report (SR) version of the Healthy Aging Brain Care Monitor (HABC-M), spanning multiple domains, into Japanese and analysed its reliability and validity in a post-intensive care setting.

METHODS

Patients aged 20 years or older and admitted to the adult intensive care unit from August 2019 to January 2021 were included and surveyed by questionnaire. The 21-item Dementia Assessment Sheet for the Regional Comprehensive Care System was used to validate cognitive and physical aspects, and the Patient Health Questionnaire-9, the Generalized Anxiety Disorder-7, and the Post Traumatic Stress Disorder Checklist for Diagnostic and Statistical Manual of Mental Disorders 5th edition were used to validate emotional aspects. Reliability was assessed by Cronbach's alpha, and congruent validity by correlation analysis. Multivariate linear regression models were used to identify potential factors for PICS.

RESULTS

A total of 104 patients (mean age: 64 ± 14 years) with 3 median mechanical ventilation days (interquartile range: 2-5) were enrolled. The Cognitive domain of the HABC-M SR was highly correlated with memory and disorientation (r = 0.77 for each), while the Functional domain was highly correlated with Instrumental Activities of Daily Living Scale (r = 0.75-0.79). The Behavioural/Psychological domain highly correlated with the Patient Health Questionnaire-9, Generalized Anxiety Disorder-7, and Post Traumatic Stress Disorder Checklist for Diagnostic and Statistical Manual of Mental Disorders 5th edition (r = 0.75-0.76). Multivariate analysis revealed longer ICU stays associated with lower Cognitive and Functional (p = 0.03 for each) domains and longer mechanical ventilation days with a lower Behavioural/Psychological domain (p < 0.01).

CONCLUSION

The translated Japanese HABC-M SR showed high validity for assessment of the Cognitive, Functional, and Behavioural/Psychological domains of PICS. Therefore, we recommend that the Japanese version of the HABC-M SR be routinely used in the assessment of PICS.

POS0687 INHIBITION OF BONE EROSION, DETERMINED BY HIGH-RESOLUTION PERIPHERAL QUANTITATIVE COMPUTED TOMOGRAPHY (HR-pQCT), IN RHEUMATOID ARTHRITIS PATIENTS RECEIVING A CONVENTIONAL SYNTHETIC DMARD (csDMARD) PLUS DENOSUMAB VS csDMARD THERAPY ALONE: RESULTS OF AN OPEN-LABEL, RANDOMIZED, PARALLEL-GROUP STUDY

Background

Denosumab, a human IgG2 monoclonal antibody with high affinity for RANKL, is approved for treatment of bone erosion (ER) in patients with RA, based on the results of clinical trials. However, its effectiveness in combination with conventional therapy in RA patients has not been fully investigated in clinical practice.

Objectives

This exploratory study aimed to compare, in patients receiving conventional synthetic disease-modifying anti-rheumatic drugs (csDMARD) for treatment of RA, the effectiveness of combined use of csDMARD and denosumab vs csDMARD alone, in terms of inhibition of ER determined by HR-pQCT.

Methods

Detail protocol of this open-label, randomized, parallel-group study has been published previously.1 RA patients with moderate or low disease activity and progressive ER were eligible, and were randomly assigned to receive denosumab in addition to the csDMARD (denosumab) group or to continued use of the csDMARD alone (csDMARD) group. Denosumab was administered every 6 months during the 12-month study period. The primary endpoint was change in ER-depth at the second and third metacarpal bones, determined by HR-pQCT at month 6. For the primary endpoint, a linear mixed effect model analysis was performed using treatment group, sex, anti-cyclic citrullinated peptide (CCP) antibody (positive vs negative), and baseline disease activity (DAS28-ESR) as fixed effects, patients as random effects, and baseline values as covariates. For extension data, measurement time-point and the interaction between treatment group and measurement time-point was further added as fixed effects. The adverse events (AEs) were recorded.

Results

A total of 46 patients were randomized to denosumab and csDMARD groups (both N=23), and baseline characteristics were similar between both groups. Although the difference was not significant, the estimate mean (95%CI) change of ER-depth at month 6 from baseline as the primary endpoint was −0.57 (−1.52, 0.39) in the denosumab group vs −0.22 (−0.97, 0.53) in the csDMARD group, respectively. At months 6 and 12, ER-depth, -width, and -volume (extension data) were numerically lower in the denosumab group than in the csDMARD group (Table 1). Compared with patients in the csDMARD group, those in the denosumab group had significantly higher volumetric bone mineral density (vBMD) at month 12. AEs were reported in 12 (52.2%) and 13 (56.5%) of patients in the denosumab and csDMARD groups, respectively. The most common AEs of denosumab groups was hypocalcemia (reported in 4), and all the events were causally related with denosumab. Serious AEs were reported in 1 (4.3%) and 2 (8.7%) of patients in the denosumab and csDMARD groups, and which were not related to treatment drug.

Table 1.

ER and microstructure in denosumab group vs csDMARD group

MonthDenosumab group (n=21)csDMARDs group (n=22)Difference (Denosumab- csDMARDs)n1Estimate Means [95%CI]n1Estimate Means [95%CI]Estimate Means [95%CI]ER-depth617−0.46 [−1.31, 0.39]25−0.20 [−0.89, 0.49]−0.27 [−0.86, 0.32]1217−0.56 [−1.41, 0.29]22−0.20 [−0.90, 0.49]−0.35 [−0.95, 0.24]ER-width617−0.26 [−1.10, 0.57]25−0.06 [−0.73, 0.61]−0.20 [−0.81, 0.40]1217−0.27 [−1.10, 0.56]22−0.03 [−0.70, 0.64]−0.24 [−0.85, 0.38]ER-volume616−6.21 [−23.89, 11.46]24−1.71 [−16.07, 12.66]−4.51 [−16.67, 7.65]1217−6.25 [−23.94, 11.44]21−3.18 [−17.56, 11.20]−3.07 [−15.32, 9.17]vBMD6426.41 [2.78, 10.03]442.46 [−1.33, 6.24]3.95 [−0.05, 7.94]12389.20 [5.46, 12.95]423.66 [−0.15, 7.46]5.55 [1.46, 9.63]*

These were extension data.

This is the efficacy analysis set which excluded 3 patients from the full analysis set.

*; p<0.01

n, number of patients; n1, number of measurement points

Conclusion

Our results suggest that adding denosumab to csDMARD therapy may help prevent ER, promote ER repair, and improve bone microstructure.

References

[1]Iwamoto N, et al., Trials. 2019;20(1):1–8.

Disclosure of Interests

Naoki Iwamoto Speakers bureau: Daiichi Sankyo Co., Ltd., Grant/research support from: Daiichi Sankyo Co., Ltd., Ko Chiba Speakers bureau: Daiichi Sankyo Co., Ltd., Shuntaro Sato: None declared, Kazuteru Shiraishi: None declared, Konosuke Watanabe: None declared, Nozomi Ohki: None declared, Akitomo Okada: None declared, Tomohiro Koga: None declared, Makiko Kobayashi Employee of: Daiichi Sankyo Co., Ltd. (retired at submission), Kengo Saito Employee of: Daiichi Sankyo Co., Ltd., Naoki Okubo Employee of: Daiichi Sankyo Co., Ltd., Atsushi Kawakami Speakers bureau: Daiichi Sankyo Co., Ltd., Grant/research support from: Daiichi Sankyo Co., Ltd.

Severity and prevalence of burnout syndrome in paediatric intensive care nurses: A systematic review

OBJECTIVES

The aim of this study is to identify burnout syndrome severity and prevalence in paediatric intensive care unit nurses.

DESIGN

Systematic review.

SETTING

Paediatric intensive care unit.

MAIN OUTCOME MEASURES

A librarian was consulted on methodology before the search process. MEDLINE (via PubMed), EMBASE, the Cochrane Library, CINAHL, and PsycINFO were searched for full-text studies published before September 2019 in any language. Only those observational studies exploring burnout syndrome, including paediatric intensive care unit nurses, were included. Two authors independently screened studies. We assessed the risk of bias within each study based on the Office of Health Assessment and Translation tool.

RESULT

After screening 1238 articles, we identified six studies which met the systematic review criteria. All studies included were published after 2012 and participant sample sizes were between 35 and 195 nurses. Three studies were conducted in the United States of America while the others were from the United Kingdom, Turkey and Taiwan. Prevalence of burnout syndrome in pediatric intensive care unit nurses was reported in these studies as between 42% and 77%. The assessment tools used in these studies were the (abbreviated) Maslach Burnout Inventory, Abbreviated Maslach Burnout Inventory, Occupational Burnout Inventory, and Professional Quality of Life Scale Version 5. We could not conduct a meta-analysis due to the lack of studies.

CONCLUSION

Our systematic review identifies that a low number (6 total) of relevant studies focused on burnout syndrome for pediatric intensive care unit nurses with a prevalence of burnout syndrome in paediatric intensive care unit nurses of between 42% and 77%.

St. Luke's International University and University of North Carolina at Chapel Hill collaboration project to develop the first DNP program in Japan

We report an international collaborative project to develop the first Doctor of Nursing Practice (DNP) program in Japan. We described the development and implementation of the first DNP program at the St. Luke's International University in Tokyo and the collaboration with the University of North Carolina at Chapel Hill in the United States. Faculty perceptions in both parties gradually evolved from the traditional perspective of international collaboration to the transitional and the beginning of the holistic partnership perspectives. The collaboration resulted in an innovative DNP program that directly addressed the gap between nursing education programs and Japan's clinical needs. The collaborative project cultivated a holistic international partnership. Rather than reporting a manual for international collaboration, we present our reflections and outcomes as narratives that others could use to achieve a holistic global partnership.

Severe COVID-19 Infection Associated with Endothelial Dysfunction Induces Multiple Organ Dysfunction: A Review of Therapeutic Interventions

Since December 2019, the SARS-CoV-2 (COVID-19) pandemic has transfixed the medical world. COVID-19 symptoms vary from mild to severe and underlying chronic conditions such as pulmonary/cardiovascular disease and diabetes induce excessive inflammatory responses to COVID-19 and these underlying chronic diseases are mediated by endothelial dysfunction. Acute respiratory distress syndrome (ARDS) is the most common cause of death in COVID-19 patients, but coagulation induced by excessive inflammation, thrombosis, and disseminated intravascular coagulation (DIC) also induce death by multiple-organ dysfunction syndrome. These associations imply that maintaining endothelial integrity is crucial for favorable prognoses with COVID-19 and therapeutic intervention to support this may be beneficial. Here, we summarize the extent of heart injuries, ischemic stroke and hemorrhage, acute kidney injury, and liver injury caused by immune-mediated endothelial dysfunction that result in the phenomenon of multi-organ dysfunction seen in COVID-19 patients. Moreover, the potential therapeutic effect of angiotensin receptor blockers and angiotensin-converting enzyme inhibitors that improve endothelial dysfunction as well as the bradykinin storm are discussed.

Ion tracks in silicon formed by much lower energy deposition than the track formation threshold

Damaged regions of cylindrical shapes called ion tracks, typically in nano-meters wide and tens micro-meters long, are formed along the ion trajectories in many insulators, when high energy ions in the electronic stopping regime are injected. In most cases, the ion tracks were assumed as consequences of dense electronic energy deposition from the high energy ions, except some cases where the synergy effect with the nuclear energy deposition plays an important role. In crystalline Si (c-Si), no tracks have been observed with any monomer ions up to GeV. Tracks are formed in c-Si under 40 MeV fullerene (C₆₀) cluster ion irradiation, which provides much higher energy deposition than monomer ions. The track diameter decreases with decreasing the ion energy until they disappear at an extrapolated value of ~ 17 MeV. However, here we report the track formation of 10 nm in diameter under C₆₀ ion irradiation of 6 MeV, i.e., much lower than the extrapolated threshold. The diameters of 10 nm were comparable to those under 40 MeV C₆₀ irradiation. Furthermore, the tracks formed by 6 MeV C₆₀ irradiation consisted of damaged crystalline, while those formed by 40 MeV C₆₀ irradiation were amorphous. The track formation was observed down to 1 MeV and probably lower with decreasing the track diameters. The track lengths were much shorter than those expected from the drop of S_e below the threshold. These track formations at such low energies cannot be explained by the conventional purely electronic energy deposition mechanism, indicating another origin, e.g., the synergy effect between the electronic and nuclear energy depositions, or dual transitions of transient melting and boiling.

Matrix-material dependence on the elongation of embedded gold nanoparticles induced by 4 MeV C60 and 200 MeV Xe ion irradiation

We report the elongation of embedded Au nanoparticles (NPs) in three different matrices, i.e. amorphous carbon (a-C), crystalline indium tin oxide (In_xSn_1-xO_z; ITO) and crystalline calcium fluoride (CaF₂), under irradiations of 4 MeV C₆₀ ⁺ cluster ions and 200 MeV Xe¹⁴⁺ ions. Under 4 MeV C₆₀ cluster irradiation, strong sputtering is induced in CaF₂ layer so that the whole the layer was completely lost at a fluence of 5 × 10¹³ ions cm^-2. Au NPs were partly observed in the SiO₂, probably due to the recoil implantation. Amorphous carbon (a-C) layer exhibits low sputtering loss even under 4 MeV C₆₀ irradiation. However, the elongation in a-C layer was low. While the ITO layer showed a certain decrease in thickness under 4 MeV C₆₀ irradiation, large elongation of Au NPs was observed under both 4 MeV C₆₀ and 200 MeV Xe irradiation. The ITO layer preserved the crystallinity even after large elongation was induced. This is the first report of the elongation of metal NPs in a crystalline matrix.

Learning experiences and identity development of Japanese nursing students through study abroad: a qualitative analysis

OBJECTIVES

This study aimed to qualitatively analyze the experiences and perceptions of students at a nursing college in Japan who studied abroad in Asia and North America, thereby identifying the full range of benefits of study abroad programs for Japanese nursing students.

METHODS

We conducted a qualitative analysis of the reflection papers and free-response questionnaire items completed by 50 Japanese undergraduate nursing students who participated in 9 study abroad programs in Asia and North America. Content analysis of the data proceeded from typological and deductive to data-driven and inductive, recursively and collaboratively.

RESULTS

The results reveal perceived benefits in the areas of English language proficiency and motivation; knowledge of nursing practices, healthcare systems, and global health; cultural awareness and sensitivity; and various types of identity development (second-language motivation and identity, national/ethnic identity, professional identity, identity as a global citizen, and personal growth). It was also shown that students' perceptions of what they learned or gained varied according to the specific characteristics of each study abroad program.

CONCLUSIONS

Study abroad experiences are often critical turning points that enhance nursing students' identity formation in the context of multiple and overlapping communities of practice. They also enhance core elements of the educational mission of a nursing college, particularly relating to liberal arts and internationalization. These findings can inform the development of assessment tools to be used in conjunction with study abroad programs at nursing colleges.

Hillocks created for amorphizable and non-amorphizable ceramics irradiated with swift heavy ions: TEM study

In a previous study, we found that hillocks (i.e. surface ion tracks) can be imaged using transmission electron microscopy (TEM) by irradiating thin CeO₂ samples with swift heavy ions (SHI) at oblique incidence. In the present study, the same TEM method is applied to Y₃Fe₅O₁₂ (YIG) and three fluorides (CaF₂, SrF₂ and BaF₂) for observing hillocks. For YIG, which is one of the amorphizable materials, hillocks are found to have amorphous features consistent with amorphous features of ion tracks. For the fluorides, it is found that the hillocks do not exhibit amorphous features, and they are composed of nanocrystallites. Although hillocks for YIG and CaF₂ exhibit different crystallographic features, hillock diameter agrees with the molten region diameter predicted by the thermal spike model for both materials. It is found that for YIG the hillock diameter is comparable to the ion track diameter, whereas for the fluorides it is always larger than the ion track diameter. The present result shows the existence of the velocity effect for ion track diameter in CaF₂. It is also found that for fluorides both hillock and ion track diameters vary in the order of cation mass (i.e. CaF₂ < SrF₂ < BaF₂). The above results of hillocks and ion tracks for SHI-irradiated fluorides can be consistently interpreted within the framework of the thermal spike model, if melting and successive recrystallization are assumed.

Increased ghrelin signaling prolongs survival in mouse models of human aging through activation of sirtuin1

Caloric restriction (CR) is known to retard aging and delay functional decline as well as the onset of diseases in most organisms. Ghrelin is secreted from the stomach in response to CR and regulates energy metabolism. We hypothesized that in CR ghrelin has a role in protecting aging-related diseases. We examined the physiological mechanisms underlying the ghrelin system during the aging process in three mouse strains with different genetic and biochemical backgrounds as animal models of accelerated or normal human aging. The elevated plasma ghrelin concentration was observed in both klotho-deficient and senescence-accelerated mouse prone/8 (SAMP8) mice. Ghrelin treatment failed to stimulate appetite and prolong survival in klotho-deficient mice, suggesting the existence of ghrelin resistance in the process of aging. However, ghrelin antagonist hastened death and ghrelin signaling potentiators rikkunshito and atractylodin ameliorated several age-related diseases with decreased microglial activation in the brain and prolonged survival in klotho-deficient, SAMP8 and aged ICR mice. In vitro experiments, the elevated sirtuin1 (SIRT1) activity and protein expression through the cAMP-CREB pathway was observed after ghrelin and ghrelin potentiator treatment in ghrelin receptor 1a-expressing cells and human umbilical vein endothelial cells. Furthermore, rikkunshito increased hypothalamic SIRT1 activity and SIRT1 protein expression of the heart in the all three mouse models of aging. Pericarditis, myocardial calcification and atrophy of myocardial and muscle fiber were improved by treatment with rikkunshito. Ghrelin signaling may represent one of the mechanisms activated by CR, and potentiating ghrelin signaling may be useful to extend health and lifespan.

Efficacy of Whole Bowel Irrigation Using Solutions with or without Adsorbent in the Removal of Paraquat in Dogs

1 The efficacy of whole bowel irrigation with a solution containing either polyethylene glycol (PEG) with electrolyte or an adsorbent (Kayexalate™) with a cathartic (sorbitol) was investigated in 18 dogs who had been given 250 mg kg -1 paraquat dichloride via a jejunal tube to eliminate the influence of gastric absorption.

2 Plasma paraquat concentrations 2 and 3 h after the initiation of bowel irrigation and at the end of the study (5 h later) were significantly lower in the bowel irrigation groups than in the control (no bowel irrigation) group.

3 The total body clearances of paraquat in the bowel irrigation groups were significantly greater than in the control group.

4 There were no significant differences between the two different irrigation solution groups in plasma paraquat concentration, the area under the plasma concentration time curve and the total body clearance.

5 In the PEG with electrolyte group, about 70% of the administered dose of paraquat was removed by means of bowel irrigation (n=4).

6 The adjunction of the adsorbent had no beneficial effects.

7 Haemodynamic changes associated with whole bowel irrigation were unremarkable except that right atrial and pulmonary arterial pressures were elevated in the latter part of the study.

Experimental evidence of crystalline hillocks created by irradiation of CeO₂ with swift heavy ions: TEM study

In this study, CeO2 was irradiated with 200 MeV Au ions at oblique incidence. Observation of as-irradiated samples by transmission electron microscopy (TEM) shows that hillocks are created not only at the wide surfaces, but also at the crack faces of the thin samples. Since the hillocks created at the crack faces can be imaged by TEM, their shape and crystallographic features can be revealed. From the images of hillocks created at the crack faces, many of the hillocks are found to be spherical. We present the first experimental evidence that hillocks created for CeO2 irradiated with swift heavy ions have a crystal structure whose lattice spacing and orientation coincide with those of the matrix. The mechanism of spherical crystalline hillock formation is discussed based on the present results.

Three-year denosumab treatment in postmenopausal Japanese women and men with osteoporosis: results from a 1-year open-label extension of the Denosumab Fracture Intervention Randomized Placebo Controlled Trial (DIRECT)

SUMMARY

A 12-month extension phase of DIRECT in Japanese subjects with osteoporosis showed that total 3 years of denosumab treatment in Japanese postmenopausal women and men with osteoporosis was associated with low fracture rates, persistent bone turnover marker (BTM) reductions, continuous bone mineral density (BMD) increases, and a favorable overall benefit/risk profile.

INTRODUCTION

The DIRECT trial demonstrated that 2 years of treatment with denosumab 60 mg subcutaneously every 6 months significantly reduced the incidence of vertebral fracture compared to placebo in Japanese postmenopausal women and men with osteoporosis. The purpose of this study is to evaluate the efficacy and safety of denosumab treatment for up to 3 years.

METHODS

This study includes a 2-year randomized, double-blind, placebo-controlled phase and a 1-year open-label extension phase in which all subjects received denosumab. The data correspond to 3 years of denosumab treatment in subjects who received denosumab (long-term group) and 1 year of denosumab treatment in subjects who received placebo (cross-over group) in the double-blind phase.

RESULTS

Eight hundred and ten subjects who completed the double-blind phase enrolled into the extension phase, and 775 subjects completed the study. All subjects received denosumab with daily supplements of calcium and vitamin D. The cumulative 36-month incidences of new or worsening vertebral fractures and new vertebral fractures were 3.8 and 2.5 %, respectively, in the long-term group. In this group, the BMD continued to increase, and the reduction in BTMs was maintained. In the cross-over group, comparable BMD increases and BTMs reductions to those of in their first year of the long-term group were confirmed. Adverse events did not show a notable increase with long-term denosumab administration. One event of osteonecrosis of the jaw occurred in the cross-over group.

CONCLUSIONS

Three-year denosumab treatment in Japanese subjects with osteoporosis showed a favorable benefit/risk profile.

Optical birefringence of Zn nanoparticles embedded in silica induced by swift heavy-ion irradiation

Zn nanoparticles (NPs) embedded in a silica matrix subjected to irradiation with swift heavy ions of 200 MeV Xe¹⁴⁺ have been found to undergo shape elongation from spheres to prolate-spheroids while maintaining the major axes of the NPs in parallel alignment. The directionally-aligned Zn spheroids enable acquisition of optical properties, such as linear dichroism and birefringence. In this paper, the birefringence of the Zn spheroids was evaluated by the crossed-Nicols (XN) transmittance, where a sample was inserted between a pair of optical polarizers that were set in an orthogonal configuration. Linearly-polarized light aligned by the first polarizer was transformed to an elliptic polarization by the birefringence of the Zn spheroids. The existence of the birefringence was confirmed by the non-zero transmittance of the second polarizer in the orthogonal configuration. The sample irradiated with a fluence of 5.0 × 10¹³ ions/cm² exhibited a maximum XN transmittance of 2.1% at a photon energy of ~4 eV. The XN transmission was observed down to a fluence of 1.0 × 10¹² ions/cm², but reduced below the detection limit at a fluence of 1.0 × 10¹¹ ions/cm². The possible application of the elongated Zn NPs as a polarizer with nanometric thickness working in the near- and mid-ultraviolet region is discussed.

Shape elongation of Zn nanoparticles in silica irradiated with swift heavy ions of different species and energies: scaling law and some insights on the elongation mechanism

Zinc nanoparticles (NPs) embedded in silica were irradiated with swift heavy ions (SHIs) of seven different combinations of species and energies. The shape elongation induced by the irradiations was evaluated by optical linear dichroism (OLD) spectroscopy, which is a sensitive tool for determining the change in the mean aspect ratio (AR) of NPs. Although the mean AR change indicated a linear fluence dependence in the low- and medium-fluence regions, it indicated a nonlinear dependence in the high-fluence region. The data reveal that the elongation efficiency of Zn is correlated with the electronic stopping power 'Se in silica' and is not correlated with either the 'Se in Zn' or the nuclear stopping power. The elongation efficiency plotted as a function of the 'Se in silica' revealed a linear relationship, with a threshold value of ∼2 keV nm(-1), which is the same dependence exhibited by the ion-track formation in silica. The log-log plot showed that the elongation efficiency increased linearly with Se above a critical value of ∼3 keV nm(-1) and steeply decreased with Se to the power of 5 below the critical Se. The steep decrease can be ascribed to the discontinuous nature of the ion tracks, which is expected at Se ∼ 2-4 keV nm(-1) in silica. The fluence Φ dependences of AR - 1 under various irradiations are well-normalized with the electronic energy deposition of SHIs, i.e., the product of Se and Φ, with a Se greater than the same critical value of ∼3 keV nm(-1). The normalized data above the critical value fell on a linear relation, AR(Φ) - 1 ∝ SeΦ, for SeΦ < 2 keV nm(-3) and a sublinear relation, AR(Φ) - 1 ∝ (SeΦ)(1/2) for SeΦ > 2 keV nm(-3). On the basis of these experimental results, we discuss some insights into the elongation mechanism.

Administration of exogenous acylated ghrelin or rikkunshito, an endogenous ghrelin enhancer, improves the decrease in postprandial gastric motility in an acute restraint stress mouse model

BACKGROUND

Physical or psychological stress causes functional disorders in the upper gastrointestinal tract. This study aims to elucidate the ameliorating effect of exogenous acylated ghrelin or rikkunshito, a Kampo medicine which acts as a ghrelin enhancer, on gastric dysfunction during acute restraint stress in mice.

METHODS

Fasted and postprandial motor function of the gastric antrum was wirelessly measured using a strain gauge force transducer and solid gastric emptying was detected in mice exposed to restraint stress. Plasma corticosterone and ghrelin levels were also measured. To clarify the role of ghrelin on gastrointestinal dysfunction in mice exposed to stress, exogenous acylated ghrelin or rikkunshito was administered, then the mice were subjected to restraint stress.

KEY RESULTS

Mice exposed to restraint stress for 60 min exhibited delayed gastric emptying and increased plasma corticosterone levels. Gastric motility was decreased in mice exposed to restraint stress in both fasting and postprandial states. Restraint stress did not cause any change in plasma acylated ghrelin levels, but it significantly increased the plasma des-acyl ghrelin levels. Administration of acylated ghrelin or rikkunshito improved the restraint stress-induced delayed gastric emptying and decreased antral motility. Ameliorating effects of rikkunshito on stress-induced gastric dysfunction were abolished by simultaneous administration of a ghrelin receptor antagonist.

CONCLUSIONS & INFERENCES

Plasma acylated/des-acyl ghrelin imbalance was observed in acute restraint stress. Supplementation of exogenous acylated ghrelin or enhancement of endogenous ghrelin signaling may be useful in the treatment of decreased gastric function caused by stress.

Biomechanical analysis for the epidural needle insertion

In order to test the hypothesis about reduction in the deformation of the ligamentum flavum due to tension inside the ligamentum flavum, nonlinear finite element (FE) analysis was employed. As a preliminary analysis of natural tissue, nonlinear FE analysis was applied to a rubber plate. Assuming that the rubber is third-order Mooney-Rivlin model, the analysis and the experimental curves overlap with each other until pierced point. The maximum major strain calculated by FE analysis was feasible to predict pierced point. To apply nonlinear FE analysis for the porcine ligamentum flavum, the Mooney-Rivlin coefficient of the porcine ligamentum flavum was identified from the tensile test data. Assuming that the sharp bar pierced the ligamentum flavum when the maximum major strain reached a constant value, the required displacement became shorter by 1.0mm by applying the initial tension.

The relationship of social norms to use of services and caregiver burden in Japan

PURPOSE

To develop an improved measure of "sekentei" (a social-psychological process that restricts behaviors that do not conform to social norms such as family caregiving) among family caregivers in Japan, and to describe the relationships among sekentei and caregiver's actual use of services, a reluctance to use services, and care burden.

DESIGN

Descriptive correlational study. Family caregivers (N = 260) of impaired elders responded to a structured questionnaire.

METHODS

Exploratory and confirmatory factor analyses were used to assess the construct validity of the sekentei scale for caregivers (SSC). With the SSC, the relationships among main variables were verified.

FINDINGS

The SSC showed satisfactory reliability and validity. Sekentei was significantly correlated with care burden, but not to actual use or reluctance to use services.

CONCLUSIONS

Sekentei is an important factor related to caregiver burden in Japan. Further research might include the extent to which sekentei is a factor in care burden in other cultures.

[Anesthetic management for left ventricular assist device implantation in patients waiting for heart transplantation]

We report the anesthetic management of patients with dilated cardiomyopathy who underwent left ventricular assist device implantation (LVAD). Anesthesia was induced and maintained with midazolam and fentanyl. Transesophageal echocardiography (TEE) and a PA catheter were useful for hemodynamic monitoring and management of the patients. Furthermore, TEE is useful for the early detection of inflow of the air which is absorbed by negative pressure derived from high LVAD support pressure. On starting LVAD support, evaluation of right ventricular function and treatment for right ventricular failure were important and necessary for the patients. Added to conventional therapy using catecholamines, inhaled nitric oxide may provide a favorable effect for right ventricular failure.

Cardiac troponin I and myocardial contusion in the rabbit

BACKGROUND

Patients with cardiac contusion have a high risk of cardiac complications during emergency anesthesia. Despite the progress in cardiac imaging, a biologic marker of myocardial damage such as cardiac troponin I remains useful and has been proposed in clinical practice. The relationship among histologic injury, left-ventricular function, and release of cardiac enzymes and cardiac troponin I has been investigated after a controlled myocardial contusion in a rabbit model.

METHODS

A global trauma (two levels of energy: 250 and 350 mJ) was produced on an isolated preparation of rabbit's heart, of which the temperature, perfusion flow, beating rate, and left-ventricular volume were kept constant. Left-ventricular pressure and its first derivative as a function of time were measured during a 60-min period after the blow; a timed collection of the effluent was made to assess creatine kinase, lactate dehydrogenase, and cardiac troponin I. At the end of the period, an anatomic score of the contusion was calculated by histologic examination of the hearts.

RESULTS

Compared with a control group, the two levels of cardiac trauma resulted in a proportional anatomic injury significantly correlated with left-ventricular dysfunction (Delta%dP/dtmax = -16 +/- 12 and -36 +/- 20% at 3 min, mean +/- SD). Transient releases in cardiac markers after the lesser amount of trauma contrasted with a prolonged and biphasic release of cardiac troponin I after the greater amount. Peak cardiac troponin I level was correlated with anatomic injury (rho = 0.596, P= 0.001) and negatively correlated with left-ventricular dysfunction (r = -0.375, P= 0.04).

CONCLUSION

Cardiac troponin I is a marker of anatomic and functional consequences of experimental cardiac trauma and may be a predictive indicator of early posttraumatic cardiac complications during the postoperative period.

Plasma lidocaine, monoethylglycinexylidide, and glycinexylidide concentrations after epidural administration in geriatric patients

BACKGROUND AND OBJECTIVES

The purpose of this study was to evaluate the effect of age on the pharmacokinetics of lidocaine after epidural administration.

METHODS

Two percent lidocaine with epinephrine (5 microg/mL) was administered in two different age groups: an adult group (age 42 +/- 6 years, n = 10) and an elderly group (age 77 +/- 4 years, n = 10). Concentrations of lidocaine and its active metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX), were measured in plasma samples obtained after 15, 30, 45, 60, 90, 120, 150, and 180 minutes of administration using high-performance liquid chromatography with ultraviolet detection.

RESULTS

No significant differences in plasma concentrations of lidocaine and its metabolites were observed between the two groups during the 3 hours of study. However, the elderly group showed significantly longer mean residence times (MRTs) and lower plasma clearance of lidocaine during the period compared with the adult group (P < .05). Plasma concentration ratios of MEGX/lidocaine were significantly lower in the elderly group after 2 hours of lidocaine administration (P < .05).

CONCLUSIONS

The increase in plasma lidocaine concentration after epidural anesthesia in elderly patients was not as high as anticipated. However, the elderly patients showed longer MRTs, lower clearance, and lower ratios of MEGX/lidocaine than did the adult (middle-age) patients.

The age-related effects of epidural lidocaine, with and without epinephrine, on spinal cord blood flow in anesthetized rabbits

The effect of epidural or spinal epinephrine when added to local anesthetics on spinal cord blood flow (SCBF)are controversial. We evaluated the effects of epidural lidocaine, with or without epinephrine, on spinal cord blood flow in young and adult rabbits receiving 2% plain lidocaine, 2% lidocaine with epinephrine (1:200,000), or saline epidurally. Colored microspheres were injected through the left ventricle 10 min before and 7.5 and 30 min after epidural injection. The organs (brain, heart, kidneys, and the L6-7 segment of the spinal cord) were analyzed for regional blood flow determination. A significant decrease in mean arterial pressure was observed after the administration of lidocaine, with or without epinephrine, in both adult and young animals compared with saline. SCBF did not change over time in adult rabbits. Conversely, a significant decrease in SCBF was observed in the two groups of young rabbits receiving lidocaine. This decrease correlated with the decrease in mean arterial pressure but did not correlate with the use of epinephrine. We conclude that any reduction in blood pressure occurring in pediatric patients receiving a combined epidural-general anesthetic may result in decreased SCBF.

IMPLICATIONS

In young rabbits, any decrease in blood pressure was followed by a decrease in spinal cord blood flow, a decrease that did not correlate to the use of epinephrine and was not observed in adult animals. These data suggest that blood pressure should be monitored closely to promptly treat any decrease in blood pressure when combined epidural-general anesthesia is used in children.

Translational regulation of angiotensin II type 1A receptor. Role of upstream AUG triplets

The cDNA sequence of rat angiotensin II type 1A receptor (AT1AR) shows that AT1AR transcripts have AUG triplets in the 5'-leader region that may begin a short open reading frame encoding an 11-amino acid peptide. In this study, the mutational inactivation of the start codon of the short open reading frame in AT1AR-chloramphenicol acetyltransferase (CAT) reporter gene constructs resulted in a 2.6-fold increase in CAT activity, whereas CAT transcript levels were not affected. Furthermore, experiments with rat AT1AR cDNA-transfected Cos-7 cells revealed that mutagenesis of the upstream AUG increased the AT1AR protein up to 2.5-fold, although AT1AR transcript levels showed no changes. The synthetic peptide corresponding to the sequence of the short open reading frame significantly suppressed the amount of AT1AR product in the in vitro translation system. The inhibiting effect of the short open reading frame appears to operate at least in part at the level of translation initiation, because polysome analysis with transfected Cos-7 cells showed that mutagenesis of the upstream AUG resulted in a shift of AT1AR mRNA distribution from a smaller to larger fraction of polysomes. Taken together, these results show that the upstream AUG inhibits translational regulation, suggesting that the short open reading frame in the 5'-leader region of AT1AR transcripts has a certain role in the translation of AT1AR protein.

[Addition of fentanyl to epidural lidocaine raises the toe temperature]

In order to investigate effects of addition of fentanyl epidurally on the onset of sympathectomy from epidural lidocaine, we have measured the toe temperature of 29 healthy patients undergoing elective lower extremity or lower abdominal surgeries. The latency of onset of the toe temperature was significantly shorter in patients receiving both epidural lidocaine and fentanyl compared with those receiving epidural lidocaine alone (258 +/- 135 vs 398 +/- 184 sec, P < 0.05 [mean +/- SD]). Osmolarity and pH of the epidural solutions were similar between the two groups. These results suggest, but do not indicate, that sympathectomy from epidural lidocaine is accelerated by the addition of fentanyl.

Spinal anesthesia attenuates myocardial ischemia during coronary artery spasm induced by intraaortic methacholine in rats

Coronary artery spasm is not rare in patients with coronary artery disease, but the influence of regional anesthesia on spasm-induced myocardial ischemia is not known. We investigated the effects of spinal anesthesia on myocardial ischemia during coronary artery spasm in rats, and compared these with the effects of an alpha- and beta-adrenergic antagonist, and an alpha-adrenergic agonist. An intraaortic catheter was inserted via the right internal carotid artery so that the tip of the catheter was placed near the coronary ostium. An intrathecal catheter was placed at lumbar level. Coronary spasm was induced by the intraaortic injection of methacholine, and we identified the thresholds of myocardial ischemia, defined as the dose of methacholine that induced ST-segment elevation. Subsequently, the thresholds were determined after spinal anesthesia, and after the intraaortic injection of phentolamine and propranolol. The thresholds of myocardial ischemia increased significantly after intrathecal bupivacaine. In contrast, the threshold did not change after the injection of phentolamine. The thresholds increased significantly after the injection of propranolol. Methoxamine significantly decreased the threshold of ischemia. These results demonstrated that spinal anesthesia attenuated myocardial ischemia during methacholine-induced coronary spasm. This effect was equivalent to that of propranolol.

Characterization of glucocorticoid response element of rat angiotensin II type 1A receptor gene

The responsiveness of the rat angiotensin II type 1a and type 1b receptor (AT1a-R and AT1b-R) genes to glucocorticoid was examined in rat vascular smooth muscle cells (VSMCs) and the glucocorticoid response element (GRE) of the AT1a-R gene was characterized. Glucocorticoid induced an increase in AT1a-R mRNA levels, whereas AT1b-R mRNA levels were unaffected. The nuclear run-off assay indicated that the transcription of the AT1a-R gene, but not that of the AT1b-R gene, was increased by glucocorticoid. The mRNA stability of AT1a-R was unchanged by glucocorticoid. Promoter/chrolamphenicol acetyltransferase reporter analysis demonstrated that the 5'-flanking region of the AT1a-R gene was functional in rat VSMCs and established that the GRE motif between -770 to -756 could confer glucocorticoid responsiveness on the AT1a-R gene.

Combined use of glucagon and milrinone may not be preferable for severe propranolol poisoning in the canine model

In a previous study of propranolol poisoning, glucagon and milrinone significantly increased cardiac output, but the improvement caused by glucagon was almost entirely due to the chronotropic effect. This study investigates the combined effect of glucagon, in a dose not inducing tachycardia, and milrinone on beta-blocker poisoning. Following the administration of 10 mg/kg propranolol IV over ten minutes, dogs (N = 20) were divided into four treatment groups, group S (saline), group G (glucagon 2.5 micrograms/kg), group M (milrinone 100 micrograms/kg), and group G + M (glucagon 2.5 micrograms/kg plus milrinone 100 micrograms/kg). Hemodynamic parameters were observed over the next thirty minutes. Heart rate, cardiac output, and mean arterial pressure were decreased in all groups after the administration of propranolol. Heart rate, mean arterial pressure, cardiac output, and stroke volume recovered to the baseline values in group G + M. However, heart rate in group G + M showed a significant increase versus the other three groups. In a canine model of severe propranolol poisoning, the combined effect of glucagon 2.5 micrograms/kg and milrinone 100 micrograms/kg brought about a significant hemodynamic improvement, but it was accompanied by an excessive increase of heart rate. Combined therapy of milrinone and glucagon may not be preferable therapy in beta-blocker poisoning in the canine model.

Age-related decrease in toe-thumb temperature difference with lumbar epidural anaesthesia

With lumbar epidural anaesthesia, big toe skin temperature increases and is associated with a compensatory decrease of thumb temperature. The purpose of the present study was to examine whether thumb-big toe temperature differences were affected by age. Following the attachment of temperature probes at the digital pad of the right big toe and the right thumb, lumbar epidural anaesthesia at L2/3 was performed in 54 patients with 10 ml lidocaine 1.5%. Big toe and thumb skin temperatures were measured continuously and recorded every minute. Fifteen minutes after epidural injection, the toe temperature increased 6.3 +/- 2.1 degrees C (delta F) from the control value, 29.4 +/- 2.2 degrees C, and the thumb temperature decreased -1.5 +/- 1.0 degrees C (delta H) from the control value, 31.6 +/- 2.8 degrees C. Regression coefficient between delta T15 (toe-thumb skin temperature 15 min after epidural injection) and age was: Y = -0.7X + 8.95 (r = 0.35, P < 0.01; Y = delta T15, X = age). The ratio of delta H to delta F and age was expressed as: Y = 0.51X - 46.57 (r = 0.41, P < 0.01: Y = delta H/delta F, X = age). It is concluded that, in lumbar epidural anaesthesia, the decrease of the thumb skin temperature is reduced with aging.

[Fluctuation of injection pressure of syringe pumps; the effect of syringe volumes and speed settings]

We measured fluctuation of injection pressure by several types of commercially available syringe pumps in order to investigate the effect of syringe volumes (Terumo syringe) and speed settings on the irregularity of injection speeds. We recorded the injection pressure continuously with various speed settings, except that one of the pumps injected irregularly at the settings of 2 and 1 ml.h-1. With 50 ml syringes, only two of the six pumps injected precisely at all the speed settings. With the other four types, a steep increase in pressure was recorded at the speed setting of 1 ml.h-1. However irregular infusion was never observed by using a syringe of a high resistant type (TOP syringe). With 30 ml syringes, injection pressures fluctuated in most of the six syringe pumps at a speed lower than 5 ml.h-1. In conclusion, changes in injection pressures depend on types of syringes, syringe volumes and speed settings. We urge not to use a 30 ml syringe to infuse vasoactive drugs with syringe pumps.

Arteriovenous differences in PCO2 and cardiac output during CPR in the dog

Using 14 mongrel dogs, we investigated the correlation between arteriovenous differences of PCO2 (AVD-CO2) and cardiac output (CO) during CPR. Ventricular fibrillation was induced by an electrical current and the respirator was stopped for 5 min. Cardiopulmonary resuscitation (CPR) was performed during the next 10 min and CO was measured with simultaneous arterial and venous blood gas analysis. CO was measured 26 times during CPR. The animals were divided into two groups according to the values of CO during CPR: low-CO group (CO < 0.3 l/min) and high-CO group (CO > or = 0.3 l/min). AVD-CO2 in the low CO group was 39.8 +/- 5.7 mmHg and that of the high group was 27.4 +/- 14.8 mmHg (mean +/- S.D., P < 0.05). In conclusion, AVD-CO2 showed an inverse result with the degree of CO during CPR.

Toe skin temperature as a guide to epidural anaesthesia dosing

To determine the time for additional epidural anaesthesia, skin temperature of the big toe was evaluated in 50 patients undergoing mastectomy. Epidural catheters were placed at or near the T5-6 intervertebral space and 12 ml, lidocaine 1.5% with 1:200,000 epinephrine were injected. When the skin temperature, which had increased following epidural anaesthesia, decreased by 0.3 degrees C without an increase of systolic arterial blood pressure (ABP) of more than 20%, 8 ml lidocaine 1.5% were injected. If the skin temperature increased, the monitor was judged to have been useful. When ABP increased > 20% without a decrease of skin temperature, the monitor was judged not to have been useful. Monitoring of toe skin temperature was useful in 39 patients (78%) in estimating the time for the first additional dose of epidural anaesthetic. First, second and third intervals between injection were 96.5 +/- 21.0 (n = 39), 69.7 +/- 14.2 (n = 35) and 50.1 +/- 12.2 min (n = 7), respectively. We conclude that, when epidural puncture is performed at upper thoracic levels, toe skin temperature can be a useful monitor to judge the time for additional anaesthetic.

Milrinone versus glucagon: comparative hemodynamic effects in canine propranolol poisoning

Glucagon has been reported to be one of the most effective treatments for severe beta-blocker poisoning. Recently, amrinone was suggested as an alternative therapeutic choice for beta-blocker poisoning. Milrinone, a derivative of amrinone, acts independently of beta-adrenoceptors and increases cyclic AMP. Therefore milrinone may also be effective in the treatment of beta-blocker poisoning. In the present study, we compared the effect of glucagon and milrinone in treating severe beta-blocker poisoning. Following the administration of 10 mg/kg propranolol i.v. over 10 min, heart rate, cardiac output, mean arterial pressure, stroke volume, and end tidal CO2 were depressed, while central venous pressure, and pulmonary capillary wedge pressure increased significantly (p < 0.05). Following the administration of saline (Group S, N = 3), glucagon 20 micrograms/kg (Group G, N = 5), and milrinone 300 micrograms/kg (Group M, N = 5), hemodynamic parameters were observed for 30 min. In group M, mean arterial pressure, cardiac output and stroke volume recovered to their baseline values, while central venous pressure and pulmonary capillary wedge pressure decreased. Although there were no significant differences between groups G and M, the heart rate, central venous pressure and pulmonary capillary wedge pressure, mean arterial pressure and stroke volume did not return to baseline values in group G. Milrinone administration produced a significant hemodynamic improvement without increasing the heart rate in the canine model of severe heart failure caused by propranolol. In the glucagon treatment group, central venous pressure and pulmonary capillary wedge pressure improved less than the milrinone group. Although more data are needed before a clinical recommendation, milrinone might be an effective drug to treat beta-blocker poisoning.

Plasma alcohol concentrations after celiac plexus block in gastric and pancreatic cancer

OBJECTIVE

The objective of this study was to compare the plasma alcohol concentrations after celiac plexus block in different types of cancer. The authors studied the consecutive changes of plasma alcohol concentrations after celiac plexus block in a gastric cancer group (group 1, n = 6) and a pancreatic cancer group (group 2, n = 5).

METHOD

Celiac plexus block was performed with 10 ml of absolute ethyl alcohol. In all patients, operations had been performed 1.2-3.5 years before the block. Arterial blood was sampled at 0, 5, 10, 15, 30, 60, 120, 240, and 480 minutes after the block.

RESULTS

The average dose of absolute ethyl alcohol was 0.186 g/kg in group 1 and 0.182 g/kg in group 2. Plasma alcohol concentrations in group 1 were about four times greater than those of group 2 (p < 0.01). The mean maximum level was reached at 15 minutes after injection in group 1 (44.0 +/- 5.8 mg/dl) and at 30 minutes in group 2 (13.1 +/- 2.4 mg/dl).

CONCLUSION

Plasma alcohol concentrations after celiac plexus block showed different patterns according to the site of cancer and the type of operation performed.

End-tidal CO2 and plasma lactate level: a comparison of their use as parameters for evaluating successful CPR

Serial changes of end-tidal CO2 (ETCO2) and plasma lactate levels during CPR have been described as useful to investigate or evaluate the results of CPR. However, there have been no reports comparing these parameters in the same model. By inducing cardiopulmonary arrest (2-7 min) in 28 Wistar rats, ETCO2 and serum lactate levels were studied after and just before CPR, respectively. In the survived group (N = 16), ETCO2 was maintained in high levels (20.1-16.3 mmHg), however in the non-survived group (N = 12), ETCO2 showed an abrupt decline (6.0-2.0 mmHg). The lactate levels before CPR in two groups were significantly higher than those of control levels, however there was no significant difference just before the CPR between the two groups. ETCO2 during CPR is a useful indicator for determining the successful application of CPR. However, serum lactate levels sampled just before the onset of CPR did not prove to be a useful indicator of successful CPR in rats.

Residual left ventricular pump function after acute myocardial infarction in NIDDM patients

OBJECTIVE

Left ventricular remodeling occurs immediately after MI, involving structural changes in noninfarcted segment. However, the residual left ventricular pump function in NIDDM patients after acute MI has not been clarified. The purpose of this study was to evaluate the difference in the process of left ventricular remodeling between NIDDM and nondiabetic patients.

RESEARCH DESIGN AND METHODS

Left ventricular regional EF images obtained by radionuclide angiography were investigated in 20 NIDDM and 29 nondiabetic patients the 3rd wk after acute MI.

RESULTS

Regional EF of the noninfarcted area and P/V had a significant hyperbolic relation with left ventricular EDV in both groups of patients. Despite no difference in the extent of myocardial necrosis and the number of coronary vessels diseased between NIDDM and nondiabetic patients, regional EF of the noninfarcted area and P/V were significantly lower when left ventricular EDV increased in NIDDM patients compared with nondiabetic patients.

CONCLUSIONS

Pathogenetic changes of the residual myocardium associated with NIDDM may adversely influence the process of left ventricular remodeling after MI, especially in patients with increased left ventricular EDV.

Arteriovenous differences of blood alcohol concentrations after celiac plexus block

After a celiac plexus block with ethyl alcohol, patients sometimes complain of symptoms of alcohol intoxication. We studied the consecutive changes of arterial and venous blood alcohol concentrations in 11 patients and investigated whether an arteriovenous difference exists. We performed a celiac plexus block with 10 ml absolute ethyl alcohol. The sampling sites were radial artery and internal jugular vein. Blood samples were collected at 0, 5, 10, 15, 30, 60, 120, 240 and 480 minutes after the block. The maximum level was reached 15 minutes after injection in both arterial and venous blood, 29.9 +/- 19.4 and 27.7 +/- 21.8 mg/dl (means +/- SD), respectively. Arteriovenous differences were observed 5 and 10 minutes after ethyl alcohol injection (p less than 0.01). There was a significant negative correlation between the ratio of arteriovenous differences to venous sampling and the time elapsed after the block (r = 0.41, p less than 0.01).

Left ventricular function in myocardial infarction. Predictive value during negative low-level exercise three weeks postinfarction

To evaluate whether the response of left ventricular pump function during low-level exercise in the early postinfarction period can anticipate its change during the first year after acute myocardial infarction (MI), global and regional ejection fractions (EF) were investigated using radionuclide angiography in 52 consecutive patients with negative predischarge exercise test. The changes in left ventricular EF and regional EF of the noninfarcted area during the early exercise test had a good linear relation with the changes during the first year after MI (r = 0.86, p less than 0.001 and r = 0.81, p less than 0.001, respectively). Our results indicate that the mobilization of the Frank-Starling mechanism and myocardial contractility were the important factors related to the change of left ventricular EF, and that the changes of left ventricular EF during exercise in the patient with a negative predischarge exercise test can predict the direction of change (concordant rise or fall) during the first year after MI.