Acute circumflex coronary artery occlusion; dilemma in diagnosis and management

Background

Acute coronary syndrome (ACS) with occlusion of the circumflex coronary artery (LCX) poses diagnostic dilemma that may lead to a delay in reperfusion.

Purpose

We sought to assess the diagnostic significance of initial electrocardiography (ECG) changes in patients with acute LCX occlusion in relation to its clinical characteristics and the management.

Methods

From consecutive 1269 patients with ACS who were admitted to our institution during a 5-year period (2015–2019), 138 patients with ACS due to LCX occlusion were analyzed for clinical, ECG and angiographic presentation, and the door-to-balloon (DTB) time. ECG changes were classified into 4 different patterns: 1) ST-elevation in inferior/lateral leads (ST-E); 2) ST-depression in V1-V4 (ST-D); 3) no significant ST changes (No-ST); and 4) others.

Results

(1) No-ST pattern was found in 47 patients (34%), ST-E in 47 patients (34%), ST-D in 25 patients (18%) and others in 19 patients (14%). (2) Occlusion site: Proximal LCX; 16 patients with No-ST (34%), 6 patients with ST-E (13%), 13 patients with ST-D (52%). Distal LCX; 28 patients with No-ST (60%), 35 patients with ST-E (74%), 11 patients with ST-D (44%) (p=0.007). (Table) (3) Echocardiographic identification of left ventricular asynergy; 31 patients with No-ST (66%), 38 patients with ST-E (81%), 22 patients with ST-D (88%). (4) No-ST group was associated with longer DTB time; 245 min (170–562 min), compared to 93 min (83–121 min) in ST-E group and 97 min (70–129 min) in ST-D group (p<0.0001). DTB time ≤90 min was significantly uncommon in No-ST group (11%), compared to ST-E group (46%) and ST-D group (43%) (p=0.0004). (Figure)

Conclusion

One-third of the patients with LCX-ACS showed no ST changes, resulting in significantly longer DTB time. Improving diagnostic accuracy with anticipation for LCX-ACS and the use of echocardiographic examination and also the possible application of posterior leads (V7-V9) recording is challenging but critical to avoid delayed reperfusion and to improve outcomes in these patients without ECG changes.

Funding Acknowledgement

Type of funding sources: None.

Comparison of coronary atherosclerotic features in response to achieving LDL-C <55 mg/dl between non-diabetic and diabetic patients: insights from the REASSURE-NIRS registry

Introduction

Current ESC guideline recommends achieving LDL-C <1.4 mmol/l in very high-risk subjects. Despite fabvourable anti-atherosclerotic effects of lowering LDL-C, its efficacy is diminished in type 2 diabetic patients. Whether response of coronary atheroma to on-treatment LDL-C <1.4 mmol/l differs in diabetic and non-diabetic subjects has not been elucidated yet.

Methods

The REASSURE-NIRS registry is an on-going multi-center registry to enroll CAD subjects receiving PCI under the guidance of near-infrared spectroscopy/intravascular ultrasound (NIRS/IVUS: DualProTM, Nipro, Tokyo, Japan) imaging. Culprit lesions in 557 CAD patients who already received a statin were evaluated by NIRS/IVUS. Maximum 4-mm-lipid-core burden-index (maxLCBI4mm) and plaque calcification grade at culprit sites were measured. Calcification grade at each 1-mm cross-sectional image was defined as follows: calcium arc 0° = 0, 0–90° = 1, 90–180° = 2, 180–270° = 3, 270–360° = 4. MaxLCBI4mm and the averaged calcification grade were compared in diabetic and non-diabetic subjects stratified according to on-treatment LDL-C level, respectively.

Result

The proportion of diabetic (n=293, HbA1c; 6.9±0.9%) and non-diabetic patients (n=264) with on-treatment LDL-C <1.4 mmol/l was 8.54 and 16.67%, respectivey (p=0.01). In non-diabetic patients, achieving LDL-C <1.4mmol/L was associated with a lower maxLCBI4mm, whereas, in diabetic patients, maxLCBI4mm was numerically smaller under achieving LDL-C <1.4 mmol/l, but this comparison did not meet statistical significance (Figure 1). Furthermore, a greater degree of calcification grade in non-diabetic patients was observed in association with on-treatment LDL-C level (Figure 2). However, plaque calcification at diabetic coronary atheroma was not necessarily induced under achieving stricter LDL-C goal. Subgroup analysis demonstrated that diabetic patients with body mass index ≥25 (odds ratio = 0.15; 95% CI: 0.18–1.19, p=0.04), estimated glomerular filtration rate <60 (mL/min/1.73m2) (odds ratio = 0.31; 95% CI: 0.10–0.90, p=0.03) and non-insulin use (odds ratio = 0.36; 95% CI: 0.14–0.87, p=0.02) benefit from achieving LDL-C <1.4 mmol/l.

Conclusion

Achieving LDL-C <1.4 mmol/l was associated with more stabilized atheroma in non-diabetic patients with CAD, whereas these favourable effects were not observed in diabetic subjects. Our findings suggest the potential need to modify additional atherogenic risks for stabilizing diabetic coronary atheroma under achieving LDL-C <1.4 mmol/l.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Inhibition of fibrotic changes in infrapatellar fat pad alleviates persistent pain and articular cartilage degeneration in monoiodoacetic acid-induced rat arthritis model

OBJECTIVE

We have reported that fibrotic changes in infrapatellar fat pad (IFP) after acute joint inflammation are closely associated with persistent pain in rats. In this study, to examine the effects of anti-fibrotic treatment on persistent pain, we used C-type natriuretic peptides (CNP) at the recovery phase after acute joint inflammation.

DESIGN

Thirty-two male Wistar rats were used in this study. Monoiodoacetic acid (MIA) was injected intra-articularly to induce IFP fibrosis and persistent pain. CNP was injected after acute inflammatory phase in the same knee joint. Time-course pain-avoidance behavior tests and histological analyses were performed to examine the effects of CNP.

RESULTS

Histological evaluations indicated that intra-articular injection of CNP inhibited fibrotic changes in IFP after acute inflammation. Incapacitance tests indicated that MIA injection into rat knee joint quickly decreased the percent weight on ipsilateral limb. In the vehicle group, the decrease was maintained up to day 28, suggesting that pain persistence occurred after acute inflammation (Day 0/Day 28, Est Dif -8.15, CI -10.78∼-5.53, Linear mixed-effect model). In contrast, the pain was alleviated in the CNP group after day 14 (Day0/Day 14, -0.51, -2.62-1.59). In addition, we observed significant improvement in the degree of articular cartilage degeneration at day 14 in the CNP group (OARSI score: vehicle 16.14 ± 4.37 vs CNP 6.87 ± 3.44, P < 0.01; Wilcoxon rank sum test).

CONCLUSION

Fibrotic changes in IFP may play important roles in both persistent pain and articular cartilage degeneration.

Characterization of thromboembolic and bleeding risks in cancer patients with acute myocardial infarction under the use of guideline-recommended dual-antiplatelet therapy

Background

Atherosclerotic cardiovascular disease including acute myocardial infarction (AMI) has become one of major co-existing diseases in cancer patients due to their improved survival rate. Current guideline recommends dual-antiplatelet therapy (DAPT) in patients with AMI. Given that the presence of cancer elevates not only coagulability but bleeding risks, these substrate may further worsen cardiovascular outcomes and bleeding risks in cancer subjects with AMI receiving DAPT.

Methods

We retrospectively analyzed 712 AMI patients treated by primary PCI with drug-eluting stent and DAPT between 2007 and 2017. The diagnosis of cancer was determined through medical record review. Clinical characteristics, thromboembolic (=all-cause death+non-fatal MI+stroke) and bleeding events were compared in AMI subjects with vs. without cancer.

Results

Cancer was identified in 11.1% (=79/712) of study subjects. Of these, around 40% of them had gastrointestinal cancer (=35/79), followed by lung cancer (=5/79) and breast cancer (=8/79). Cancer patients were more likely to be older (77±7 v. 69±13 years, p&lt;0.001) with a history of Af (25 v. 10%, p&lt;0.001), CKD (eGFR&lt;60: 60 v. 42%, p=0.002), anemia (hemoglobin: 12.8±1.8 v. 13.9±1.8 g/dl, p&lt;0.001). Under anti-thrombotic (DAPT=86%, triple-antiplatelet therapy=14%) and optimal medical therapies (ACE-I=90%, beta-blocker=76%, statin=96%), more frequent occurrence of thromboembolic events was observed in patients with cancer (34.2 v. 12.6%, p=0.004, Picture). Furthermore, the presence of cancer was associated with more than four times greater risk of bleeding events compared to non-cancer subjects (18.9 v. 4.3%, p&lt;0.001, Picture). In particular, the frequency of both major (10.1 vs. 3.3%, p=0.003) and minor (8.9 vs. 0.9%, p&lt;0.001) bleeding events was significantly higher in patients with cancer. In multivariate analysis, cancer independently predicted bleeding events (Table).

Conclusions

Under the use of guideline recommended DAPT, the concomitance of cancer in AMI subjects was a predictor for thromboembolic as well as bleeding events. In particular, the relationship between cancer and bleeding was significant. These observations underscore the appropriate selection and duration of anti-thrombotic agents in AMI subjects with cancer.

Cardiac/Bleeding Events in AMI Subjects

Funding Acknowledgement

Type of funding source: None

Characterization of plaque features exhibiting physiological mismatch between fractional flow reserve and resting index: near-infrared spectroscopy imaging analysis

Background

In addition to fractional flow reserve (FFR), resting indexes (RI) have been shown as another physiological measure to evaluate myocardial ischemia. Despite the clinical usefulness of RI without the use of intravenous vasodilatory agent, discrepancy between FFR and RI infrequently occurs. Whether this physiological mismatch is derived by specific plaque feature remains unknown.

Purpose

To characterize coronary plaques associated with coronary physiological mismatch.

Methods

We analyzed 59 coronary arteries (LAD/RCA/LCX=49/4/6) with FFR≤0.80 in 57 stable CAD subjects receiving PCI. Following measurement of FFR and RI, culprit lesion was evaluated by near-infrared spectroscopy and intravascular ultrasound (NIRS/IVUS). The analyzed vessels were stratified according to FFR and RI values: FFR≤0.75+RI&gt;0.89 (n=6: physiological mismatch), FFR&gt;0.75+RI&gt;0.89 (n=6), FFR≤0.75+RI≤0.89 (n=33) and FFR&gt;0.75+RI≤0.89 (n=14).

Results

The median values of percent diameter stenosis, FFR and RI were 51%, 0.75 and 0.87, respectively. Physiological mismatch was observed in 10.1% (=6/59) of analyzed vessels. On IVUS imaging, maximum percent plaque area was greater than 70% in all groups (p=0.29). Furthermore, there were no significant differences in angiographic and IVUS-derived minimum lumen area across 4 groups (Table). However, culprit lesions exhibiting physiological mismatch contained a substantially larger amount of lipid plaque, reflected by a higher maximum 4-mm lipid-core burned index (maxLCBI4mm: p=0.04) on NIRS imaging (Table). Multivariate analysis demonstrated maxLCBI4mm as the only plaque feature associated with physiological mismatch (odds ratio=1.010, 95% CI: 1.001–1.019, p=0.02).

Conclusion

Plaque feature associated with coronary physiological mismatch was the extent of lipidic materials but not the quantity of coronary atheroma. Since the accumulation of lipidic plaque component is caused by endothelial dysfunction, this vascular substrate could impair baseline vasomotion, thereby causing a lower FFR despite preserved RI value. Evaluation of lipidic burden may be a potential option to avoid unnecessary deferral of revascularization in subjects with normal RI value.

maxLCBI4mm in each group

Funding Acknowledgement

Type of funding source: None

P5635Predictive ability of lipdic burden for FFR-derived physiological measures: insights from near-infrared spectroscopy imaging analysis

Background

Fractional flow reserve (FFR) has enabled to physiologically assess the myocardial ischemia of coronary artery with intermediate stenosis. Mechanistically, not only the severity of coronary stenosis but also the extent of maximal vasodilatation within the entire coronary artery potentially affects this physiological measure. Since the accumulation of lipidic materials within vessel wall increases vascular stiffness via inducing endothelial dysfunction, the presence of lipidic atheroma burden may affect physiological measures.

Purpose

To investigate the association of FFR with lipidic coronary atheroma by near-infrared spectroscopy/intravascular ultrasound (NIRS/IVUS) imaging, which quantitatively visualize lipidic burden in vivo.

Methods

We analyzed 61 coronary arteries (LAD/RCA/LCX=52/5/4) with FFR≤0.80 in 59 stable coronary artery disease subjects receiving PCI. Following FFR measurement, NIRS/IVUS imaging was conducted to evaluate the extent of atheroma burden (maximum percent plaque area=max%PA) and lipidic materials (lipid core burden index within the entire vessel=LCBIvessel). The analyzed vessels were stratified according to FFR: definite FFR group (FFR≤0.74, n=34) and gray-zone FFR group (0.75≤FFR≤0.80, n=27).

Results

NIRS/IVUS imaging analysis (analyzed longitudinal length=77±7mm) was more likely to exhibit a significantly higher LCBIvessel and a larger max%PA in the definite FFR group (Table). Of note, FFR was significantly correlated to LCBIvessel (ρ=-0.299, p=0.02), but not max%PA (ρ=-0.255, p=0.07). Multivariate analysis demonstrated that an independent determinant of FFR≤0.74 was LCBIvessel [odds ratio (OR)=1.016, 95% confidential interval (CI)=1.002–1.031, p=0.02], but not max%PA [OR=1.084, 95% CI=0.994–1.182, p=0.07]. Area under the receiver-operating characteristic curve analysis elucidated that the addition of LCBIvessel to angiography- and IVUS-derived measures resulted in a significant improvement for detecting FFR≤0.74 (picture).

Definite FFR Group (FFR≤0.74, n=34) Gray-zone FFR Group (0.75≤FFR≤0.80, n=27) p value Fractional flow reserve (FFR) 0.68±0.05 0.78±0.02 <0.01 Percent diameter stenosis (%) 56.2±13.1 51.9±7.8 0.16 Maximum percent plaque area (max%PA, %) 84.3±6.9 79.9±7.2 0.01 Lipid core burden index within the entire vessel (LCBIvessel) 102.0±60.2 65.6±51.6 0.01

ROC analysis for detecting FFR≦0.74

Conclusion

The propagation of lipidic burden associates with the physiological measures. The present findings indicate the possibility that vessel characteristics or instability may have influence for causing ischemia on the coronary artery.

P1561An elevated risk of heart failure and stroke events in octogenarian Japanese patients with acute myocardial infarction who received percutaneous coronary intervention

Background

The proportion of the octogenarian population is expanding especially in Eastern society. Due to the clustering of risk factors, acute myocardial infarction (AMI) represents a major cardiovascular complication in octogenarian subjects. This suggests the need to further optimize their therapeutic management to prevent future cardiac events after AMI. However, analysis of clinical characteristics and cardiovascular outcomes in octogenarian subjects with AMI who received the current established medical therapies is limited.

Purpose

To investigate clinical features and prognosis in octogenarian AMI subjects treated with percutaneous coronary intervention (PCI).

Methods

We analyzed 1547 AMI subjects underwent PCI between 2007 and 2017. Baseline characteristics and the occurrence of composite major adverse cardiovascular events (cardiac death, non-fatal MI, revascularization, heart failure and stroke) were compared in octogenarian and non-octogenarian subjects.

Results

22.0% (340/1547) of study subjects was octogenarian. They were more likely to have chronic kidney disease (CKD) and a lower level of LDL-C on admission (Table). Moreover, a higher prevalence of severer Killip class and LVEF <30% were observed in octogenarians (Table). However, they were not optimally treated with the established medical therapies at discharge (Table). During the observational period (median=3.1 years), the composite of cardiovascular events more frequently occurred in octogenarian subjects. Of note, they exhibited a 2.15-fold and 3.01-fold increased risk for heart failure and stroke events, respectively (Figure).

Table 1 Non-Octogenarian (n=1207) Octogenarian (n=340) P-value CKD* (%) 33.8 63.2 <0.0001 LVEF <30% (%) 5.7 10.3 0.02 Killip class 1.33±0.03 1.55±0.05 <0.0001 LDL-C (mmol/L) 3.20±0.03 2.80±0.05 <0.0001 Statin (%) 86.3 78.2 0.0006 Beta-blocker (%) 74.0 65.8 0.005 ACE-I/ARB (%) 87.3 76.6 <0.0001 DAPT (%) 86.0 88.6 0.42 *CKD is defined as estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2.

Figure 1

Conclusions

Octogenarian subjects with AMI were high-risk group associated with heart failure and stroke events. Their distinct clinical backgrounds may affect the adoption of optimal medical therapies, potentially resulting in worse cardiovascular outcomes. Further intensified management should be applied to octogenarian subjects with AMI.

Plasma natriuretic peptide levels in fetuses with congenital heart defect and/or arrhythmia

OBJECTIVE

Diagnosing fetal heart failure remains challenging because it is difficult to know how well the fetal myocardium will perform as loading conditions change. In adult cardiology, natriuretic peptides (NPs) are established markers of heart failure. However, the number of studies investigating NP levels in fetuses is quite limited. The aim of this study was to evaluate the significance of plasma NP levels in the assessment of heart failure in fetuses with a congenital heart defect (CHD) and/or arrhythmia.

METHODS

This was a prospective observational study conducted at a tertiary pediatric cardiac center. A total of 129 singletons with CHD and/or arrhythmia and 127 controls were analyzed between 2012 and 2015. Umbilical cord plasma atrial NP, brain NP and N-terminal pro-brain NP levels at birth were compared with ultrasonography findings indicating fetal heart failure, such as cardiovascular profile (CVP) score and morphological characteristics.

RESULTS

Fetuses with CHD and/or arrhythmia had higher NP levels than did controls (P < 0.01). NP levels of fetuses with CHD and/or arrhythmia were correlated inversely with CVP score (P for trend < 0.01). No differences in NP levels were found in fetuses with CHD and/or arrhythmia and a CVP score of ≥ 8 in comparison to controls. Multivariate analysis showed that a CVP score of ≤ 5, tachy- or bradyarrhythmia at birth, preterm birth and umbilical artery pH < 7.15 were associated independently with high NP levels (P < 0.01). Among fetuses with a CVP score of ≤ 7, abnormal venous Doppler sonography findings were significantly more common and more severe in fetuses with tachy- or bradyarrhythmia than in those with CHD, and those with tachy- or bradyarrhythmia had higher NP levels than did those with CHD (P = 0.01). Fetuses with right-heart defect and moderate or severe tricuspid valve regurgitation had significantly higher NP levels than did fetuses with other types of CHD (P < 0.01).

CONCLUSIONS

Plasma NP levels in fetuses with CHD and/or arrhythmia are correlated with the severity of fetal heart failure. Elevated NP levels are attributed mainly to an increase in central venous pressure secondary to arrhythmia or atrioventricular valve regurgitation due to CHD, rather than to the morphological abnormality itself. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Effect of basal insulin therapy on vascular endothelial function and adipokine profiles in people with Type 2 diabetes

AIM

To compare the effects of the basal insulin analogues glargine and detemir on endothelial function and adipocytokine levels in people with Type 2 diabetes.

METHODS

We studied 32 people with Type 2 diabetes whose blood glucose control was unsatisfactory while receiving only oral hypoglycaemic drugs. Participants were randomized to either insulin glargine or detemir for 24 weeks and then crossed over to the other treatment without a washout period. Flow-mediated vasodilatation, adipocytokine levels (plasminogen activator inhibitor-1 and leptin/adiponectin ratio), and fasting ghrelin levels were monitored.

RESULTS

HbA_1c levels were significantly decreased by both basal insulin therapies. Body weight was significantly increased by glargine but not by detemir. The proportion of flow-mediated vasodilatation was significantly increased by detemir but not glargine (glargine: from 5.17 ± 0.69 to 5.94 ± 0.83%; detemir: from 4.89 ± 0.78 to 7.92 ± 0.69%). Plasminogen activator inhibitor-1 level was significantly decreased by only detemir (glargine: from 16.4 ± 1.8 to 17.3 ± 2.1; detemir: from 19.2 ± 2.8 to 16.0 ± 1.6 ng/ml). The leptin/adiponectin ratio was significantly increased only by glargine. Acyl ghrelin level was significantly decreased by glargine but not detemir.

CONCLUSIONS

These results suggest that the effect on endothelial function and adipocytokine profiles may differ between glargine and detemir in people with diabetes (Trial registration ID: UMIN000004973).

How to Embolize Wide-Necked Aneurysms?

Novel endovascular approaches are needed for safer and more definitive treatment of wide-necked aneurysms, to overcome the limitations of the Guglielmi detachable coil (GDC) system and further, the application of this technique.

The double GDC technique (DGT), for embolization of wide-necked aneurysms, and the combination of stent placement and coil deposition (CTSC) for management of fusiform aneurysms have been developed and their usefulness is reviewed. The DGT involves scaffolding of a GDC coil to form a stabilizing frame inside the aneurysmal neck and then positioning of a second coil to reinforce the first coil. After confirming the absence of coil herniation in the parent artery, both coils are released together. A patient with a wide-necked large aneurysm of the left internal carotid artery was treated using this technique, and followed up angiographically and clinically for a period of three months. The follow-up angiograms revealed complete embolization of the aneurysm.

The patient had no neurological changes or adverse events during the procedure. The CTSC involves reconstructing the artery with a stent and packing the aneurysm lumen with GDCs through the stent interstices. A patient with a dissecting fusiform aneurysm of the vertebral artery associated with hypoplasia of the contralateral vertebral artery was treated using this technique to prevent rebleeding. His clinical course was uneventful over a six-month follow-up period. Angiography performed two months after the procedure confirmed excellent flow through the right vertebral artery and absence of filling of the daughter aneurysm.

Characterizing a fast-response, low-afterglow liquid scintillator for neutron time-of-flight diagnostics in fast ignition experiments

The characteristics of oxygen-enriched liquid scintillators with very low afterglow are investigated and optimized for application to a single-hit neutron spectrometer for fast ignition experiments. It is found that 1,2,4-trimethylbenzene has better characteristics as a liquid scintillator solvent than the conventional solvent, p-xylene. In addition, a benzophenon-doped BBQ liquid scintillator is shown to demonstrate very rapid time response, and therefore has potential for further use in neutron diagnostics with fast time resolution.

Randomized clinical trial: rikkunshito in the treatment of functional dyspepsia--a multicenter, double-blind, randomized, placebo-controlled study

BACKGROUND

Rikkunshito, a standardized Japanese herbal medicine, is thought to accelerate gastric emptying and relieve dyspepsia, although no large-scale, randomized, placebo-controlled trials of rikkunshito have been conducted. This study aimed to determine the efficacy and safety of rikkunshito for treating functional dyspepsia (FD).

METHODS

FD patients received 2.5 g rikkunshito or placebo three times a day for 8 weeks in this multicenter, randomized, placebo-controlled, parallel-group trial. The primary end point was the proportion of responders at 8 weeks after starting test drug, determined by global patient assessment (GPA). The improvement in four major dyspepsia symptoms severity scale was also evaluated. In addition, plasma ghrelin levels were investigated before and after treatment.

KEY RESULTS

Two hundred forty-seven patients were randomly assigned. In the eighth week, the rikkunshito group had more GPA responders (33.6%) than the placebo (23.8%), although this did not reach statistical significance (p = 0.09). Epigastric pain was significantly improved (p = 0.04) and postprandial fullness tended to improve (p = 0.06) in the rikkunshito group at week 8. Rikkunshito was relatively more effective among Helicobacter pylori-infected participants (rikkunshito: 40.0% vs placebo: 20.5%, p = 0.07), and seemed less effective among H. pylori-uninfected participants (rikkunshito: 29.3% vs placebo: 25.6%, p = 0.72). Among H. pylori-positive individuals, acyl ghrelin levels were improved just in rikkunshito group. There were no severe adverse events in both groups.

CONCLUSIONS & INFERENCES

Administration of rikkunshito for 8 weeks reduced dyspepsia, particularly symptoms of epigastric pain and postprandial fullness. (UMIN Clinical Trials Registry, Number UMIN000003954).

The photonuclear neutron and gamma-ray backgrounds in the fast ignition experiment

In the fast-ignition scheme, very hard x-rays (hereinafter referred to as γ-rays) are generated by Bremsstrahlung radiation from fast electrons. Significant backgrounds were observed around the deuterium-deuterium fusion neutron signals in the experiment in 2010. In this paper the backgrounds were studied in detail, based on Monte Carlo simulations, and they were confirmed to be γ-rays from the target, scattered γ-rays from the experimental bay walls (γ'-rays), and neutrons generated by (γ, n) reactions in either the target vacuum chamber or the diagnostic instruments (γ-n neutrons).

Quantitative measurement of hard x-ray spectra for high intensity laser produced plasma

X-ray line spectra ranging from 17 to 77 keV were quantitatively measured with a Laue spectrometer, composed of a cylindrically curved crystal and a detector. Either a visible CCD detector coupled with a CsI phosphor screen or an imaging plate can be chosen, depending on the signal intensities and exposure times. The absolute sensitivity of the spectrometer system was calibrated using pre-characterized laser-produced x-ray sources and radioisotopes. The integrated reflectivity for the crystal is in good agreement with predictions by an open code for x-ray diffraction. The energy transfer efficiency from incident laser beams to hot electrons, as the energy transfer agency for specific x-ray line emissions, is derived as a consequence of this work.

Obsessive-compulsive behavior as a symptom of dementia in progressive supranuclear palsy

AIMS

To describe obsessive-compulsive symptoms (OCS) as under-recognized behavioral and psychological symptoms of dementia of progressive supranuclear palsy (PSP) and to discuss possible mechanisms based on MRI and SPECT findings.

METHODS

We studied 74 PSP patients. OCS are defined as persistent and unreasonable, but non-delusional/hallucinatory, ideas and behaviors. Demography, cognition, the widths of middle cerebellar peduncles (MCP) and the inter-caudate distances (ICD), both corrected by the intracranial size (MCP and ICD ratios), and changes on voxel-based SPECT were compared between the subgroups with and without OCS. Finally, the predicative power of various factors to OCS was investigated.

RESULTS

We observed OCS in 18 patients (24%). They were obsessed with daily trifles and physical symptoms among other things. OCS was not associated with demography or cognitive levels. OCS-positive patients had significantly smaller MCP and ICD ratios and showed marked uptake decreases in the orbitofrontal cortex, caudate and thalamus. Relative uptake increases in the cerebellum, specifically the tonsils, were milder in OCS-positive than -negative patients. A smaller right MCP, a smaller ICD ratio and lower uptake increases in the right cerebellar were the significant predictors of OCS.

CONCLUSIONS

OCS are frequent but under-recognized behavioral and psychological symptoms of dementia in PSP. Dysfunction of the fronto-caudate-thalamus-cerebellum circuit may be involved.

Down-scattered neutron imaging detector for areal density measurement of inertial confinement fusion

A custom developed (6)Li glass scintillator (APLF80+3Pr) for down-scattered neutron diagnostics in inertial confinement fusion experiments is presented. (6)Li provides an enhanced sensitivity for down-scattered neutrons in DD fusion and its experimentally observed 5-6 ns response time fulfills the requirement for down-scattered neutron detectors. A time-of-flight detector operating in the current mode using the APLF80+3Pr was designed and its feasibility observing down-scattered neutrons was demonstrated. Furthermore, a prototype design for a down-scattered neutron imaging detector was also demonstrated. This material promises viability as a future down-scattered neutron detector for the National Ignition Facility.

Visuospatial dysfunction may be a key in the differentiation between Alzheimer's disease and subcortical cognitive impairment in moderate to severe stages

AIMS

Recent studies have suggested that subcortical cognitive impairment (SubCI) and Alzheimer's disease (AD) can be differentiated by visuospatial tasks. We addressed at what severity stage these differences become apparent and what components in visuospatial processes are subject to impairment.

METHODS

Sixty patients with AD, 22 with vascular cognitive impairment and 63 with extrapyramidal diseases with cognitive impairment were assessed using the revised Hasegawa Dementia Scale (HDSR), clock drawing/reading/matching tests (CDT, CRT, CMT), figure copying (FIG) and Frontal Assessment Battery (FAB). Patients were categorized according to the HDSR scores in order to control for the severity of global cognitive impairment. Raw scores were converted to Z-scores for comparisons.

RESULTS

In the mild stage, results of all measures were comparable between AD and SubCI. In the moderate-severe stage, scores of CDT, CRT, CMT, FIG and FAB were significantly lower in SubCI. The results suggest that (given that global cognition is controlled for) visuo-perception, visuo-construction and semantic-numerical analyses of visual information may be more impaired in SubCI than AD.

CONCLUSIONS

AD and SubCI may be difficult to be differentiated in the mild stages, and the visuospatial cognitive system may be extensively defective in SubCI.

Experimental evidence of impact ignition: 100-fold increase of neutron yield by impactor collision

We performed integrated experiments on impact ignition, in which a portion of a deuterated polystyrene (CD) shell was accelerated to about 600 km/s and was collided with precompressed CD fuel. The kinetic energy of the impactor was efficiently converted into thermal energy generating a temperature of about 1.6 keV. We achieved a two-order-of-magnitude increase in the neutron yield by optimizing the timing of the impact collision, demonstrating the high potential of impact ignition for fusion energy production.

Ghrelin stimulates milk intake by affecting adult type feeding behaviour in postnatal rats

The influence of ghrelin on feeding behaviour during infancy is unknown. To determine whether ghrelin influences milk intake in rat pups, newborn rats received a single i.p. injection of either rat ghrelin (100 microg/kg) or rabbit anti-ghrelin immunoglobulin G (100 microg/kg) every 5 days from postpartum day 5 to day 30 (P5-P30). Milk intake was then assessed by body weight gain following a 2-h suckling period. Ghrelin significantly increased weight gain relative to vehicle-injected controls in P20, P25 and P30 pups, but not in younger animals. Similarly, after 8 h of milk restriction, anti-ghrelin injections significantly decreased weight gain in P25 and P30, but not in younger pups. Interestingly, however, ghrelin did increase independent feeding in P10 and P15 pups using a paradigm in which pups consumed milk from a milk-soaked paper towel. We therefore conclude that ghrelin stimulates milk intake at an early postnatal stage, primarily by affecting adult-type feeding behaviour.

Ghrelin prevents development of diabetes at adult age in streptozotocin-treated newborn rats

AIMS/HYPOTHESIS

Ghrelin, a stomach-derived hormone, functions in multiple biological processes, including glucose metabolism and cellular differentiation and proliferation. In this study, we examined whether early treatment with ghrelin can regenerate beta cells of the pancreas in an animal model of diabetes mellitus, the n0-STZ model, in which neonatal rats are injected with streptozotocin (STZ) at birth.

METHODS

Following administration of ghrelin to n0-STZ rats from postnatal days 2 to 8, we examined beta cell mass, mRNA expression levels of insulin and of pancreatic and duodenal homeobox 1 (Pdx1) gene, and pancreatic morphology on days 21 and 70. In addition, we investigated the effects of ghrelin on beta cell replication.

RESULTS

By day 21, ghrelin treatment increased pancreatic expression of insulin and Pdx1 mRNA in n0-STZ rats. The number of replicating cells was also significantly increased in the ghrelin-treated n0-STZ model. At day 70, n0-STZ rats exhibited hyperglycaemia, despite slight increases in plasma insulin levels. Ghrelin treatment resulted in the improvement of plasma glucose levels, which were associated with normal plasma insulin levels. Pancreatic insulin mRNA and protein levels were significantly increased in ghrelin-treated n0-STZ model animals.

CONCLUSIONS/INTERPRETATION

These findings suggest that ghrelin promotes regeneration of beta cells in STZ-treated newborn rats. Thus, early administration of ghrelin may help prevent the development of diabetes in disease-prone subjects after beta cell destruction.

Tight regulation of transgene expression by tetracycline-dependent activator and repressor in brain

Methods to temporally and spatially regulate gene mutations will provide a powerful strategy to investigate gene function in the brain. To develop these methods, we have established a tightly regulated system for transgene expression in the forebrain using both a tetracycline (Tc)-dependent transcription activator (rtTA) and a repressor (TetR-Kruppel-associated box). In this system, the repressor binds to the Tc-responsive element (TRE) in the absence of doxycycline (Dox), leading to the repression of leaky activation of TRE-mediated transcription caused by weak binding of rtTA to TRE. Upon Dox administration, only the activator binds to TRE and activates transcription. We tested this system in cultured cells by bicistronically expressing both the regulators using an internal ribosome entry site (IRES). In COS-1, HeLa and SHSY5Y cells, leaky transcription activation led by rtTA in the absence of Dox was repressed without decreasing the level of activated transcription in the presence of Dox. Using this system, transgenic mice were produced that express both the regulators using IRES in the forebrain under the control of the alphaCaMKII promoter and were bred with transgenic mice carrying the TRE-dependent reporter transgene. In reverse transcription-polymerase chain reaction and in situ hybridization analyses of the forebrain in adult double transgenic mice, the treatment of Dox induces reporter mRNA expression, which was not detected before the treatment and after the withdraw of Dox following the treatment. These results indicate that this system allows the tight regulation of transgene expression in a Dox-dependent fashion in the forebrain and will be useful in investigating gene function in the brain.

Plasma ghrelin levels in healthy elderly volunteers: the levels of acylated ghrelin in elderly females correlate positively with serum IGF-I levels and bowel movement frequency and negatively with systolic blood pressure

Aging is associated with a decrease in growth hormone (GH) secretion, appetite and energy intake. As ghrelin stimulates both GH secretion and appetite, reductions in ghrelin levels may be involved in the reductions in GH secretion and appetite observed in the elderly. However, only preliminary studies have been performed on the role of ghrelin in elderly subjects. In this study, we sought to clarify the physiologic implications of the age-related alterations in ghrelin secretion by determining plasma ghrelin levels and other clinical parameters in healthy elderly subjects. Subjects were > or = 65 years old, corresponding to the SENIEUR protocol, had not had a resection of the upper gastrointestinal tract and had not been treated with hormones. One hundred and five volunteers (49 men and 56 women) were admitted to this study (73.4 +/- 6.3 years old). Plasma levels of acylated ghrelin in elderly female subjects positively correlated with serum IGF-I levels and bowel movement frequency and negatively with systolic blood pressure. In elderly men, desacyl ghrelin levels correlated only weakly with bowel movement frequency. These findings suggest that the plasma levels of the acylated form of ghrelin may influence the age-related alterations in GH/IGF-I regulation, blood pressure and bowel motility. These observational associations warrant further experimental studies to clarify the physiologic significance of these effects.

Helicobacter pylori infection modifies gastric and plasma ghrelin dynamics in Mongolian gerbils

BACKGROUND

and aim: Although ghrelin, a novel growth hormone releasing peptide localised mainly in the gastric fundus, is reported not only to accelerate food passage and gastrointestinal motility but also to affect appetite and weight control, regulation of gastric ghrelin secretion under the conditions of gastric Helicobacter pylori infection is unknown. The present study was designed to investigate plasma and gastric ghrelin levels in Mongolian gerbils with H pylori colonisation of the gastric mucosa.

METHODS

Gerbils orally inoculated with H pylori were examined after inoculation. To examine preproghrelin mRNA expression in the gastric mucosa, cDNA encoding the gerbil preproghrelin and glyceraldehyde-3-phosphate dehydrogenase homologue was isolated and a quantitative reverse transcription-polymerase chain reaction system was established.

RESULTS

In gerbils showing H pylori colonisation (H pylori group), expression of preproghrelin mRNA and total ghrelin levels were significantly decreased 17 and 23 weeks later (p<0.01). Although the number of ghrelin immunoreactive cells decreased as the stomach weight increased, the gastric contents of total and active ghrelin in this group were the same as those in controls. Gastric myeloperoxidase activity showed a positive correlation with plasma ghrelin levels. On the other hand, at 17 weeks, plasma ghrelin levels were significantly increased in the H pylori group (p<0.05), suggesting a compensatory increase in secretion of the peptide at this time point.

CONCLUSION

The present experimental study demonstrated that gastric and plasma ghrelin dynamics are altered in response to H pylori infection.

Amidated fish ghrelin: purification, cDNA cloning in the Japanese eel and its biological activity

We purified ghrelin from stomach extracts of a teleost fish, the Japanese eel (Anguilla japonica) and found that it contained an amide structure at the C-terminal end. Two molecular forms of ghrelin with 21 amino acids were identified by cDNA and mass spectrometric analyses: eel ghrelin-21, GSS(O-n-octanoyl)FLSPSQRPQGKDKKPP RV-amide and eel ghrelin-21-C10, GSS(O-n-decanoyl) FLSPSQRPQGKDKKPPRV-amide. Northern blot and RT-PCR analyses revealed high gene expression in the stomach. Low levels of expression were found only in the brain, intestines, kidney and head kidney by RT-PCR analysis. Eel ghrelin-21 increased plasma growth hormone (GH) concentrations in rats after intravenous injection; the potency was similar to that of rat ghrelin. We also examined the effect of eel ghrelin on the secretion of GH and prolactin (PRL) from organ-cultured tilapia pituitary. Eel ghrelin-21 at a dose of 0.1 nM stimulated the release of GH and PRL, indicating that ghrelin acts directly on the pituitary. The present study revealed that ghrelin is present in fish stomach and has the ability to stimulate the secretion of GH from fish pituitary. A novel regulatory pathway of GH secretion by gastric ghrelin seems to be conserved from fish to human.

Purification and distribution of ghrelin: the natural endogenous ligand for the growth hormone secretagogue receptor

Growth hormone secretagogues (GHS) are small synthetic molecules that act through a specific G-protein coupled receptor (GPCR) termed GHS-R, which is a distinct receptor from that of growth hormone releasing hormone (GHRH). This receptor was one of the orphan GPCR, i.e. a GPCR with no known natural ligand, until we purified its endogenous ligand from rat stomach and named it "ghrelin". Ghrelin is a 28-amino-acid peptide, in which the serine 3 is modified by an n-octanoic acid and this modification is essential for ghrelin's activity. The discovery of ghrelin indicates that the release of GH from the pituitary may be regulated not only by hypothalamic GHRH, but also by ghrelin from the stomach and hypothalamus.

Hemodynamic, renal, and hormonal effects of ghrelin infusion in patients with chronic heart failure

Ghrelin is a novel GH-releasing peptide that may also induce vasodilation and a positive energy balance through GH-independent mechanisms. However, the hemodynamic, renal, and hormonal effects of ghrelin in patients with chronic heart failure (CHF) remain unknown. Accordingly, 12 patients with CHF were given an iv infusion of human ghrelin (0.1 microg/kg.min) or placebo. Ghrelin significantly decreased mean arterial pressure (-9 mm Hg, P < 0.05) without a significant change in heart rate. Ghrelin significantly increased cardiac index (+25%, P < 0.05) and stroke volume index (+30%, P < 0.05), although it did not significantly alter mean pulmonary arterial pressure or pulmonary capillary wedge pressure. Infusion of ghrelin induced a marked increase in serum GH level (15-fold), associated with slight increases in circulating epinephrine, ACTH, cortisol, and PRL. Infusion of ghrelin did not significantly alter urine volume, urinary sodium excretion, or creatinine clearance. These hemodynamic, renal and hormonal parameters remained unchanged during placebo infusion. In summary, iv infusion of ghrelin, a potent GH-releasing peptide, had beneficial hemodynamic effects in patients with CHF in the absence of renal effects.

Bullfrog ghrelin is modified by n-octanoic acid at its third threonine residue

We have identified the amphibian ghrelin from the stomach of the bullfrog. We also examined growth hormone (GH)-releasing activity of this novel peptide in both the rat and bullfrog. The three forms of ghrelin identified, each comprised of 27 or 28 amino acids, possessed 29% sequence identity to the mammalian ghrelins. A unique threonine at amino acid position 3 (Thr(3)) in bullfrog ghrelin differs from the serine present in the mammalian ghrelins; this Thr(3) is acylated by either n-octanoic or n-decanoic acid. The frog ghrelin-28 has a complete structure of GLT (O-n-octanoyl)FLSPADMQKIAERQSQNKLRHGNM; the structure of frog ghrelin-27 was determined to be GLT(O-n-octanoyl)FLSPADMQKIAERQSQNKLRHGN; frog ghelin-27-C10 possessed a structure of GLT(O-n-decanoyl)FLSPADMQKIAERQSQNKLRHGN. Northern blot analysis demonstrated that ghrelin mRNA is predominantly expressed in the stomach. Low levels of gene expression were observed in the heart, lung, small intestine, gall bladder, pancreas, and testes, as revealed by reverse transcription polymerase chain reaction analysis. Bullfrog ghrelin stimulated the secretion of both GH and prolactin in dispersed bullfrog pituitary cells with potency 2-3 orders of magnitude greater than that of rat ghrelin. Bullfrog ghrelin, however, was only minimally effective in elevating plasma GH levels following intravenous injection into rats. These results indicate that although the regulatory mechanism of ghrelin to induce GH secretion is evolutionary conserved, the structural changes in the different ghrelins result in species-specific receptor binding.

Stomach is a major source of circulating ghrelin, and feeding state determines plasma ghrelin-like immunoreactivity levels in humans

Ghrelin, an endogenous ligand for the GH secretagogue receptor, was isolated from rat stomach and is involved in a novel system for regulating GH release. Although previous studies in rodents suggest that ghrelin is also involved in energy homeostasis and that ghrelin secretion is influenced by feeding, little is known about plasma ghrelin in humans. To address this issue, we studied plasma ghrelin-like immunoreactivity levels and elucidated the source of circulating ghrelin and the effects of feeding state on plasma ghrelin-like immunoreactivity levels in humans. The plasma ghrelin-like immunoreactivity concentration in normal humans measured by a specific RIA was 166.0 +/- 10.1 fmol/ml. Northern blot analysis of various human tissues identified ghrelin mRNA found most abundantly in the stomach and plasma ghrelin-like immunoreactivity levels in totally gastrectomized patients were reduced to 35% of those in normal controls. Plasma ghrelin-like immunoreactivity levels were increased by 31% after 12-h fasting and reduced by 22% immediately after habitual feeding. In patients with anorexia nervosa, plasma ghrelin-like immunoreactivity levels were markedly elevated compared with those in normal controls (401.2 +/- 58.4 vs. 192.8 +/- 19.4 fmol/ml) and were negatively correlated with body mass indexes. We conclude that the stomach is a major source of circulating ghrelin and that plasma ghrelin-like immunoreactivity levels reflect acute and chronic feeding states in humans.

Enhanced exercise-induced GH secretion in subjects with Pro7 substitution in the prepro-NPY

The leucine 7 to proline 7 (Leu7Pro) polymorphism in the signal peptide of NPY is associated with high blood lipid concentrations and accelerated rate of atherosclerosis as well as diabetic retinopathy. Also, healthy subjects with this polymorphism have increased NPY secretion during sympathetic stimulation. Because NPY may regulate GH release and ghrelin may regulate NPY formation, we studied the effects of the Leu7/Pro7 genotype on GH, ghrelin, and IGF-I secretion during standardized cycle-ergometer exercise. Furthermore, we studied the effect of the Leu7/Pro7 genotype on diurnal GH secretion in rest in a separate study. The subjects with Leu7/Pro7 genotype had 54% higher maximal increases in the plasma GH concentrations than the controls during exercise. There were no significant differences in the ghrelin or IGF-I concentrations during exercise among the groups. Furthermore, there were no differences in diurnal GH secretion between the genotypes. The results indicate that the prepro-NPY genotype has an influence on GH response during exercise in humans. The clinical significance of this finding is not known, and further studies are needed to evaluate whether the observed change in GH secretion during exercise could play a role in promoting diseases.

Elevated circulating level of ghrelin in cachexia associated with chronic heart failure: relationships between ghrelin and anabolic/catabolic factors

BACKGROUND

Ghrelin is a novel growth hormone (GH)-releasing peptide, isolated from the stomach, that may also cause a positive energy balance by stimulating food intake and inducing adiposity. We sought to investigate the pathophysiology of ghrelin in the cachexia associated with chronic heart failure (CHF).

METHODS AND RESULTS

Plasma ghrelin was measured in 74 patients with CHF and 12 control subjects, together with potentially important anabolic and catabolic factors, such as GH and tumor necrosis factor (TNF-alpha). Patients with CHF were divided into two groups, those with cachexia (n=28) and those without cachexia (n=46). Plasma ghrelin did not significantly differ between all CHF patients and controls (181+/-10 versus 140+/-14 fmol/mL, P=NS). However, plasma ghrelin was significantly higher in CHF patients with cachexia than in those without cachexia (237+/-18 versus 147+/-10 fmol/mL, P<0.001). Circulating GH, TNF-alpha, norepinephrine, and angiotensin II were also significantly higher in CHF patients with cachexia than in those without cachexia. Interestingly, plasma ghrelin correlated positively with GH (r=0.28, P<0.05) and TNF-alpha (r=0.31, P<0.05) and negatively with body mass index (r=-0.35, P<0.01).

CONCLUSIONS

Plasma ghrelin was elevated in cachectic patients with CHF, associated with increases in GH and TNF-alpha and a decrease in body mass index. Considering ghrelin-induced positive energy effects, increased ghrelin may represent a compensatory mechanism under catabolic-anabolic imbalance in cachectic patients with CHF.

Stomach is a major source of circulating ghrelin, and feeding state determines plasma ghrelin-like immunoreactivity levels in humans

Ghrelin, an endogenous ligand for the GH secretagogue receptor, was isolated from rat stomach and is involved in a novel system for regulating GH release. Although previous studies in rodents suggest that ghrelin is also involved in energy homeostasis and that ghrelin secretion is influenced by feeding, little is known about plasma ghrelin in humans. To address this issue, we studied plasma ghrelin-like immunoreactivity levels and elucidated the source of circulating ghrelin and the effects of feeding state on plasma ghrelin-like immunoreactivity levels in humans. The plasma ghrelin-like immunoreactivity concentration in normal humans measured by a specific RIA was 166.0 +/- 10.1 fmol/ml. Northern blot analysis of various human tissues identified ghrelin mRNA found most abundantly in the stomach and plasma ghrelin-like immunoreactivity levels in totally gastrectomized patients were reduced to 35% of those in normal controls. Plasma ghrelin-like immunoreactivity levels were increased by 31% after 12-h fasting and reduced by 22% immediately after habitual feeding. In patients with anorexia nervosa, plasma ghrelin-like immunoreactivity levels were markedly elevated compared with those in normal controls (401.2 +/- 58.4 vs. 192.8 +/- 19.4 fmol/ml) and were negatively correlated with body mass indexes. We conclude that the stomach is a major source of circulating ghrelin and that plasma ghrelin-like immunoreactivity levels reflect acute and chronic feeding states in humans.

Substantial production of ghrelin by a human medullary thyroid carcinoma cell line

Ghrelin, an endogenous ligand for the GH secretagogue receptor, is a novel acylated peptide produced in the gastrointestinal endocrine cells as well as neuroendocrine cells in the hypothalamus. The Ser(3) residue of ghrelin is modified by n-octanoic acid, a modification necessary for hormonal activity. Human medullary thyroid carcinoma is known to produce a variety of gastrointestinal and neuroendocrine peptides. In the present study we investigated ghrelin production in the thyroid gland, especially in human medullary thyroid carcinoma. PCR amplification demonstrated prepro-ghrelin gene transcripts in normal human thyroid tissue and two medullary thyroid carcinoma cell lines (human TT cells and rat 6-23 cells), but not in a rat thyroid follicular cell line. TT cells showed the expression of prepro-ghrelin mRNA of about 0.6 kb by Northern blot analysis. Furthermore, production of ghrelin in TT cells was demonstrated by RIA and immunocytochemistry. Accumulation of des-n-octanoyl ghrelin in the cultured medium of the cells was confirmed. Finally, human medullary thyroid carcinoma surgical specimens showed significantly higher des-n-octanoyl ghrelin contents than normal thyroid tissues. In conclusion, we revealed that ghrelin was produced by the human thyroid parafollicular carcinoma cell line, TT cells. These findings suggest that ghrelin is produced in the thyroid C cells as well as in medullary thyroid carcinoma and may provide opportunities to investigate its physiological role in the thyroid gland.

[Contrivance for frozen section diagnosis of early minute lung cancer during operation]

We reported the technique of pathological diagnosis for minute lung cancer lesion of early stage during operation. Target lesion for our technique may be less than 1 cm in size and not be detected by palpation. Our technique may superior to usual method of frozen section of tissue specimen without fixation. At first, resected lung specimen was fixed by injection of 20% formalin solution subsequent warming by microwave oven for 40 seconds. Almost all lesions may be detected in proper thickness of specimen. Specimen was washed out and steeped in the 20% of sucrose solution for 30 to 60 seconds in order to avoid crystallization of water that was contained within lung specimen. Then thin sliced section of specimen was made by Cryostat in usual method. The minute cancer lesion was able to detect more easy than usual method of making frozen section of specimen. Formalin fixed and sucrose steeped frozen section may be able to evaluate the surgical margin from cancer exactly than the section made by non-fixed specimen.

Chronic administration of ghrelin improves left ventricular dysfunction and attenuates development of cardiac cachexia in rats with heart failure

BACKGROUND

Ghrelin is a novel growth hormone (GH)-releasing peptide that may also induce vasodilation and stimulate feeding through GH-independent mechanisms. We investigated whether ghrelin improves left ventricular (LV) dysfunction and attenuates cardiac cachexia in rats with chronic heart failure (CHF).

METHODS AND RESULTS

Ligation of the left coronary artery or sham operation was performed; 4 weeks after surgery, rat ghrelin (100 microg/kg SC BID) or saline was administered for 3 weeks. Echocardiography and cardiac catheterization were performed. Serum GH and insulin-like growth factor-1 were significantly higher in both CHF and sham rats treated with ghrelin than in those given placebo (P<0.05 for both). CHF rats given placebo showed an impaired increase in body weight compared with sham rats given placebo (P<0.05). CHF rats treated with ghrelin, however, showed a significantly greater increase in body weight than those given placebo (+10% versus +3%, P<0.05). They showed significantly higher cardiac output (315+/-49 versus 266+/-31 mL. min(-1). kg(-1), P<0.05) and LV dP/dt(max) (5738+/-908 versus 4363+/-973 mm Hg/s, P<0.05) than CHF rats given placebo. Ghrelin increased diastolic thickness of the noninfarcted posterior wall, inhibited LV enlargement, and increased LV fractional shortening in CHF rats (from 15+/-3% to 19+/-3%, P<0.05).

CONCLUSIONS

Chronic subcutaneous administration of ghrelin improved LV dysfunction and attenuated the development of LV remodeling and cardiac cachexia in rats with CHF.

Structure-activity relationship of ghrelin: pharmacological study of ghrelin peptides

Ghrelin, a novel peptide purified from the stomach, is the endogenous ligand of the growth hormone secretagogue receptor. The Ser(3) residue of ghrelin is modified with a lipid n-octanoic acid, a modification necessary for hormonal activity. To clarify the role of acyl modification and to identify the active core of ghrelin, we examined the activities of partially digested ghrelin and synthetic ghrelin derivatives. The activities confirmed that the N-terminal portion is the active core. Moreover, synthetic ghrelin derivatives demonstrated that octanoic acid is not the only modification of the Ser(3) side chain to sustain the activity of ghrelin; other acyl acid modifications maintained activity. Amino acid replacement of Ser(3) indicated that an L-configuration of the third residue is critical for ghrelin activity. In addition, more stable ether or thioether bonds are capable of replacing the octanoyl ester bond in ghrelin, advantageous for the generation of pharmaceuticals with longer stability.

Structural similarity of ghrelin derivatives to peptidyl growth hormone secretagogues

Ghrelin is a 28-amino acid residue endogenous growth hormone secretagogue. Intensive investigations revealed that the N-terminus tetrapeptide, having octanoyl group at Ser(3), is the minimum active core. In this study, we further explored the structure-function relationships of the active N-terminus portion of ghrelin using a Ca(2+) mobilization assay. The smallest and most potent ghrelin derivative we have found so far is 5-aminopentanoyl-Ser(Octyl)-Phe-Leu-aminoethylamide, showing comparable activity to the natural molecule. In the process of modifying the active core, the ghrelin-derived short analogues emerged structurally close to peptidyl growth hormone secretagogues. The N-terminus modification suggested that Gly(1)-Ser(2) unit works as a spacer, forming adequate distance between N(alpha)-amino group and n-octanoyl group. Replacement of 3rd and 4th amino acid residues to D-isomer suggested that the N-terminal dipeptide contributes to shape the biologically active geometry by effecting conformation of residues in positions 3 and 4.

Mediastinal neurilemmoma complicated with spinal subarachnoid hemorrhage

A 28-year-old woman suffered severe back pain and headache during exercising on three occasions during the prior two-month period. On admission, the physical examination revealed symptoms of meningeal irritation, nuchal rigidity, severe headache, continuous nausea, and vomiting. Cerebral computed tomography of the intracranial subarachnoidal space revealed no subarachnoid hemorrhage. Her cerebrospinal fluid was bloody. Spinal magnetic resonance imaging identified a posterior mediastinal tumor adherent to the left side of the 5th thoracic vertebra and an abnormally expanded blood vessel near the mediastinal tumor. In addition, a high signal intensity lesion appeared to be present on the surface of the spinal cord. A mediastinal neoplasm was removed through standard thoracotomy. During surgery, marked enlargement was noted in some veins (hemiazygos and 5th intercostal veins) which apparently had been constricted by the mediastinal tumor. Surgical and radiological findings suggested a relationship between the constricted venous return due to the tumor and the patient's spinal subarachnoid hemorrhage.