A novel CT-based radiomics model for predicting response and prognosis of chemoradiotherapy in esophageal squamous cell carcinoma

No clinically relevant biomarker has been identified for predicting the response of esophageal squamous cell carcinoma (ESCC) to chemoradiotherapy (CRT). Herein, we established a CT-based radiomics model with artificial intelligence (AI) to predict the response and prognosis of CRT in ESCC. A total of 44 ESCC patients (stage I-IV) were enrolled in this study; training (n = 27) and validation (n = 17) cohorts. First, we extracted a total of 476 radiomics features from three-dimensional CT images of cancer lesions in training cohort, selected 110 features associated with the CRT response by ROC analysis (AUC ≥ 0.7) and identified 12 independent features, excluding correlated features by Pearson's correlation analysis (r ≥ 0.7). Based on the 12 features, we constructed 5 prediction models of different machine learning algorithms (Random Forest (RF), Ridge Regression, Naive Bayes, Support Vector Machine, and Artificial Neural Network models). Among those, the RF model showed the highest AUC in the training cohort (0.99 [95%CI 0.86-1.00]) as well as in the validation cohort (0.92 [95%CI 0.71-0.99]) to predict the CRT response. Additionally, Kaplan-Meyer analysis of the validation cohort and all the patient data showed significantly longer progression-free and overall survival in the high-prediction score group compared with the low-prediction score group in the RF model. Univariate and multivariate analyses revealed that the radiomics prediction score and lymph node metastasis were independent prognostic biomarkers for CRT of ESCC. In conclusion, we have developed a CT-based radiomics model using AI, which may have the potential to predict the CRT response as well as the prognosis for ESCC patients with non-invasiveness and cost-effectiveness.

Novel Biomarkers of Gastric Cancer: Current Research and Future Perspectives

Gastric cancer is a heterogeneous disease with diverse histological and genomic subtypes, making it difficult to demonstrate treatment efficacy in clinical trials. However, recent efforts have been made to identify molecular biomarkers with prognostic and predictive implications to better understand the broad heterogeneity of gastric cancer and develop effective targeted therapies for it. HER2 overexpression, HER2/neu amplification, MSI-H, and PD-L1+ are predictive biomarkers in gastric cancer, and a growing number of clinical trials based on novel biomarkers have demonstrated the efficacy of targeted therapies alone or in combination with conventional chemotherapy. Enrichment design clinical trials of targeted therapies against FGFR2b and claudin 18.2 have demonstrated efficacy in unresectable advanced gastric cancer. Nonetheless, it is essential to continuously validate promising molecular biomarkers and introduce them into clinical practice to optimize treatment selection and improve patient outcomes. In this review, we focused on established (PD-L1, HER2, MSI) and emerging biomarkers (FGFR2, CLDN18.2) in gastric cancer, their clinical significance, detection methods, limitations, and molecular agents that target these biomarkers.

Exploring rare cellular activity in more than one million cells by a transscale scope

In many phenomena of biological systems, not a majority, but a minority of cells act on the entire multicellular system causing drastic changes in the system properties. To understand the mechanisms underlying such phenomena, it is essential to observe the spatiotemporal dynamics of a huge population of cells at sub-cellular resolution, which is difficult with conventional tools such as microscopy and flow cytometry. Here, we describe an imaging system named AMATERAS that enables optical imaging with an over-one-centimeter field-of-view and a-few-micrometer spatial resolution. This trans-scale-scope has a simple configuration, composed of a low-power lens for machine vision and a hundred-megapixel image sensor. We demonstrated its high cell-throughput, capable of simultaneously observing more than one million cells. We applied it to dynamic imaging of calcium ions in HeLa cells and cyclic-adenosine-monophosphate in Dictyostelium discoideum, and successfully detected less than 0.01% of rare cells and observed multicellular events induced by these cells.

Geriatric nutritional risk index (GNRI) predicts long-term survival and limb events in patients with peripheral artery disease

Background

Geriatric nutritional risk index (GNRI) was developed as a “nutrition-related” risk index and was reported in different populations as associated with the risk of all-cause and cardiovascular morbidity and mortality.

Purpose

The purpose of this study was to assess the associations of GNRI with mortality and amputation free survival in patients with peripheral artery disease (PAD).

Methods

From January 2011 to June 2016, 295 consecutive patients (73.3±9.2 years; 75.6% male) with PAD undergoing endovascular treatment (EVT) in our hospital were retrospectively examined. The GNRI on admission was calculated as follows: 14.89 × serum albumin (g/dl) + 41.7 × body mass index (BMI)/22. Characteristics and mortality were compared between 2 groups: low GNRI (<92, n=110) with moderate or severe nutritional risk; and high GNRI (≥92, n=185) with no or low nutritional risk.

Results

The median follow up period was 39.4±26.4months. There were 85 deaths (28.8%) and 13 major amputation (4.4%) during the follow-up. Patients in the low-GNRI group were more often higher age, non-ambulatory state, hemodialysis and critical limb ischemia. BMI, serum hemoglobin, albumin, low-density lipoprotein were significantly lower, whereas serum C-reactive protein was significantly higher in the low-GNRI group than the high-GNRI group (P<0.05, respectively). Kaplan–Meier analysis revealed that patients in the low-GNRI group had a significantly lower amputation free survival, compared to those in the high-GNRI group (log-rank test, P<0.001).

Conclusion

The low GNRI is associated with an increased risk of mortality and limb events in patients with PAD.

Amputation-free survival (Kaplan-Meier)

Funding Acknowledgement

Type of funding source: None

P179 Alterations of resting heart rate and heart rate viability after cryoballon ablation in the patients with paroxysmal atrial fibrillation

Background

While it is generally accepted that cardiac autonomic nervous system (CANS) plays an important role in atrial fibrillation (AF) and pulmonary vein isolation (PVI) by radiofrequency catheter ablation modifies the ganglionated plexi (GP), the alterations of CANS after PVI are not clarified.

Purpose

The objective of this study was to investigate the alteration of CANS after conventional cryoballoon ablation (CBA) by using a non-invasive examination method of measuring resting heart rate (R-HR) and coefficient of variation of R-R interval (CVR-R) which is a representative parameter of heart rate viability. CVR-R reflects R-R interval variation affected by respiration. It is calculated from the R-R interval of consecutive 100 heart beats of sinus rhythm recorded at rest. Declines of CVR-R indicate the parasympathetic dysfunction and the normal range of it varies depend on the age. As age increases from 30s to 70s, the average value of CVR-R decreases from 4.0% to 2.4%.

Methods

Consecutive patients of paroxysmal AF treated with initial CBA in our institute participated. Subjects were limited to the patients who maintained sinus rhythm through the study and whose prescription had not been changed after procedure. All patients recorded 12-lead electrocardiogram to measure R-HR and CVR-R before and the day after the procedure. We compared R-HR and CVR-R of all patients before and after CBA. And in addition, we compared them in each of two groups whose pre-procedural H-RH were under 50 bpm (Group-U50) and over 70 bpm (Group-O70). All procedures were performed with second generation 28mm cryoballoon (CB)s under the conscious sedation with Dexmedetomidine. CB temperature was down to a minimum of -60°C and target application time was 180 seconds.

Results

In the procedure of all 105 patients (male gender, 54%; age, 66.9 ± 10.4years; CHADS2score, 1.15 ± 1.04; diabetes mellitus,14%; beta-blocker therapy, 16%), 1 of touch-up for PVI, 6 of supra vena cava isolation and 21 of cavotricuspid isthmus linear ablations with radiofrequency catheter were added. In all patients, R-HR increased from 58.9 ± 9.2bpm to 72.4 ± 9.5bpm (P < 0.01) and CVR-R decreased from 2.36 ± 1.08% to 1.24 ± 0.68% (P < 0.01), respectively. In Group-U50 (n = 14; male gender 64%; age 67.6 ± 12.4 years), R-HR increased from 47.1 ± 2.1bpm to 64.4 ± 7.9bpm (P < 0.01) and CVR-R decreased from 2.58 ± 1.59% to 1.34 ± 0.82% (P < 0.01), respectively. In Group-O70 (n = 17; male gender 43%; age 67.4 ± 12.6 years), R-HR increased from 73.7 ± 2.8bpm to 81.8 ± 7.4bpm (P < 0.01) and CVR-R decreased from 2.33 ± 0.94% to 1.14 ± 0.52% (P < 0.01), respectively. Values of CVR-R before and after CBA showed no significant difference between the two groups.

Conclusions

After CBA, R-HR increment and CVR-R decrement were significantly observed. CVR-R was halved regardless of pre–procedural R-HR. Damages to GP by CBA would be reflected as denervation of vagus nerves in CANS. R-HR increase might be associated with parasympathetic suppression of CANS.

P1917Can cryoballoon ablation produce alterations in cardiac and extra-cardiac autonomic nervous system in patients with atrial fibrillation?

Background

Cryoballoon ablation (CBA) during pulmonary vein isolation (PVI) for atrial fibrillation (AF) can cause direct thermal injury to structures adjacent to the left atrium, including the periatrial ganglionated plexi (GP). In contrast, it has not been clarified whether cardiac autonomic nervous system (CANS) modification by CBA could indirectly affect extra-CANS.

Purpose

This study was aimed to investigate the impact of CBA on extra-CANS as well as CANS in AF patients.

Methods

Ninety-three Consecutive patients who underwent initial CBA in our institute were enrolled. Among them, 64 subjects (age 67±9 years; male gender 52%; CHADS2 score 1.2±1.0; diabetes mellitus 16%; β-blocker therapy 23%) had paroxysmal AF (G-P) and 29 (age 66±7 years; male gender 90%; CHADS2 score 1.3±1.0; diabetes mellitus 24%; β-blocker therapy 34%) had sustained AF (G-S). In G-P, resting sinus heart rate (R-HR) and coefficient of variation of the R-R intervals (CVR-R) during sinus rhythm were measured in resting 12-lead electrocardiogram before and after CBA as an index of CANS. Decrease in CVR-R after PVI reflects the vagal nerve injury by the procedure. Pupil movement reflects the autonomic nervous function. In both groups, pupillary light reflex, as an indicator of extra-CANS activity, was measured by infrared videopupillography (Iriscorder® Dual C10641, Hamamatsu Photonics, Hamamatsu, Japan) before and after CBA. Velocity of dilatation (VD) is related to sympathetic function, and velocity of contraction (VC) is associated with the balance between sympathetic and vagal tone. All CBA were treated with second generation 28mm cryoballoons (CB). CB temperature was down to a minimum of −60°C and target application time was 180 seconds.

Results

Complete PVI was achieved in all patients, in which touch-up radiofrequency ablation for the PVI was required in 4 cases of G-S. In G-P, R-HR significantly increased (59.2±9.2bpm to 72.5±8.3bpm, p<0.01) and CVR-R significantly decreased (2.32±1.1% to 1.61±0.61%, p<0.01) after CBA, while VC and VD did not significantly change (3.83±1.03mm2/sec to 3.64±0.96mm2/sec and 1.83±0.62mm2/sec to 1.86±0.84mm2/sec, respectively). In G-S, there were not significant changes between before and after CBA in VC and VD (3.77±0.80mm2/sec to 3.71±0.99mm2/sec and 1.81±0.49mm2/sec to 1.80±0.59mm2/sec, respectively). There were no significant differences between two groups in VC and VD before the procedure.

Conclusion

These results suggest that CBA seems to result in local parasympathetic denervation due to damage of adjacent structures including ganglionated plexi while the alteration of CANS by CBA does not seem to efferently affect extra-CANS.

Deletion of JMJD2B in neurons leads to defective spine maturation, hyperactive behavior and memory deficits in mouse

JMJD2B is a histone demethylase enzyme that regulates gene expression through demethylation of H3K9me3. Although mutations of JMJD2B have been suggested to be responsible for neurodevelopmental disorders, the function of JMJD2B in the central nervous system (CNS) remains to be elucidated. Here we show that JMJD2B has a critical role in the development of the CNS. We observed JMJD2B expression, which was especially strong in the hippocampus, throughout the CNS from embryonic periods through adulthood. We generated neuron-specific JMJD2B-deficient mice using the cre-loxP system. We found an increase in total spine number, but a decrease in mature spines, in the CA1 region of the hippocampus. JMJD2B-deficient mice exhibited hyperactive behavior, sustained hyperactivity in a novel environment, deficits in working memory and spontaneous epileptic-like seizures. Together these observations indicate that JMJD2B mutant mice display symptoms reminiscent of neurodevelopmental disorders. Our findings provide evidence for the involvement of histone demethylation in the formation of functional neural networks during development.

Exendin-4, glucagon-like peptide-1 receptor agonist, enhances isoflurane-induced preconditioning against myocardial infarction via caveolin-3 expression

OBJECTIVE

To investigate the cardioprotective effects of isoflurane and exendin-4 against myocardial ischemia/reperfusion injury and the signaling pathways through which these effects are mediated.

MATERIALS AND METHODS

For infarct size measurements, anesthetized mice were subjected to 30 min of coronary artery occlusion followed by 2 h of reperfusion. Wild-type or caveolin-3 knockout mice received isoflurane, exendin-4, or isoflurane with exendin-4 before ischemia index determination. Caveolin-3 expression in the heart was measured by immunoblotting.

RESULTS

Myocardial infarct size was smaller in the isoflurane- [1.0 minimum alveolar concentration (MAC)] or exendin-4- (30 ng/kg i.v.) treated groups than the controls. Infarct size was not affected by isoflurane at 0.5 MAC or 3 ng/kg i.v. exendin-4, but the combination of these treatments reduced infarct size. Pharmacological preconditioning (isoflurane at 1.0 MAC, 30 ng/kg i.v. exendin-4, or isoflurane at 0.5 MAC with 3 ng/kg i.v. exendin-4) increased caveolin-3 protein expression in the heart after infarct induction. The cardioprotective effects of isoflurane, exendin-4, and isoflurane with exendin-4 were abolished in caveolin-3 knockout mice.

CONCLUSIONS

The combination of isoflurane and exendin-4 reduced infarct size, but it was not more effective than either agent alone, and the cardioprotective effects of these agents are mediated by caveolin-3 expression.

Migration ecology of juvenile temperate seabass Lateolabrax japonicus: a carbon stable-isotope approach

The migration pattern of juvenile temperate seabass Lateolabrax japonicus in the stratified estuary of the Yura River was examined using carbon stable-isotope ratios (δ(13)C). δ(13)C values of mysids, which are the most important prey items for this species, were consistently enriched in the lower estuary and surf zone (LES), while depleted in the freshwater zone (FW). δ(13)C values of juveniles in LES were enriched, while those in FW were depleted, consistent with the δ(13)C difference in prey items. The results of δ(13)C showed that many juveniles migrated upstream from April to June and most of them stayed in FW until at least July. Juveniles that stayed in FW and LES for a relatively longer period (> c. 20 days) showed higher condition factors than those that stayed in FW for a short period (several days). This indicates that residence in FW enabled juveniles to achieve as good a body condition as residence in LES.

Aerodynamic advantages of upside down take-off for aerial dispersal in Tetranychus spider mites

Aerial dispersal may be important for redistribution of spider mites into new habitats. Evidence for behavioral control of aerial take-off has been well documented for Tetranychus urticae Koch. Before aerial dispersal they exhibit the aerial take-off posture that involves lifting the forelegs upright and raising the forebody. However, whether the aerial take-off posture functions to increase drag has remained unclear. The objectives of this study were to clarify: (i) aerodynamic effects of the aerial take-off posture; and (ii) actual aerial take-off behavior in T. urticae. To evaluate the aerodynamic forces experienced by grounded spider mites in different postures, we constructed three-dimensional models of T. urticae, exhibiting the aerial take-off posture and the normal posture, using computer graphics. We found that the aerial take-off posture was effective in receiving greater rearward forces from wind rather than upward forces. As a result, aerial take-off from a horizontal platform is unlikely. Instead, inverted departure surfaces, e.g., lower leaf surfaces, with inclines are likely to be effective sites for take-off. Laboratory experiments and field observations indicated that the mites preferentially adopted such a position for orientation and take-off. Our findings provided a rationale for the take-off behavior of Tetranychus spider mites.

Atypical, bidirectional regulation of cadmium-induced apoptosis via distinct signaling of unfolded protein response

Cadmium is a widely distributed nephrotoxic metal that causes renal tubular injury. In this report, we investigated involvement of endoplasmic reticulum (ER) stress and individual unfolded protein responses in cadmium-initiated apoptosis of tubular epithelial cells. Cadmium chloride (CdCl(2)) induced expression of endogenous ER stress markers, GRP78, GRP94 and CHOP in vitro and in vivo, and subsequently caused cytological changes typical of apoptosis. Attenuation of ER stress by transfection with ER chaperone GRP78 or ORP150 suppressed CdCl(2)-triggered apoptosis. In response to CdCl(2), phosphorylation of RNA-dependent protein kinase-like ER kinase (PERK) and eukaryotic translation initiation factor 2alpha (eIF2alpha) was observed. Enhanced phosphorylation of eIF2alpha attenuated, whereas inhibition of eIF2alpha exacerbated CdCl(2)-induced apoptosis. Activating transcription factor 6 (ATF6) was also activated by CdCl(2) and blockade of this process suppressed induction of CHOP and thereby improved cell survival. CdCl(2) also triggered activation of the inositol-requiring ER-to-nucleus signal kinase 1 (IRE1)-X-box-binding protein 1 (XBP1) pathway and inhibition of XBP1 attenuated apoptosis independent of GRP78 and CHOP. c-Jun N-terminal kinase (JNK), another molecule downstream of IRE1, was also phosphorylated by CdCl(2) and its inhibition attenuated apoptosis. These results evidenced bidirectional regulation of apoptosis in cadmium-exposed cells. The ATF6 and IRE1 pathways cooperatively caused apoptosis via induction of CHOP, activation of XBP1 and phosphorylation of JNK, and the PERK-eIF2alpha pathway counteracted the proapoptotic processes.

Screening and identification of substances that regulate nephrin gene expression using engineered reporter podocytes

Downregulation of nephrin in podocytes leads to development of proteinuria in human and experimental kidney diseases. However, little is understood about pathophysiologic substances that regulate nephrin expression. In this report, we established conditionally immortalized reporter podocytes REPON for sensitive, continuous monitoring of nephrin gene expression. A murine podocyte cell line harboring a temperature-sensitive simian virus 40 large T antigen was stably transfected with a gene encoding secreted alkaline phosphatase (SEAP) under the control of the 5.4 or 8.3 kb nephrin gene promoter. The established reporter cells REPON5.4 and REPON8.3 were exposed to various pathophysiologic substances, and culture media were subjected to SEAP assay to identify regulators of nephrin gene expression. Among the bioactive substances tested, three physiological ligands of nuclear receptors including all-trans-retinoic acid, 1,25-dihydroxyvitamin D3, and dexamethasone significantly activated the nephrin gene promoter in a dose-dependent manner. These effects were observed in both REPON5.4 and REPON8.3 and were associated with upregulation of nephrin mRNA. The effects of these substances were synergistic, and the maximum effect was observed by combination of three agents. In contrast, inflammatory cytokines interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha as well as phorbol ester significantly downregulated the activity of the nephrin promoter as well as nephrin gene expression. These results elucidated the bidirectional regulation of nephrin by distinct pathophysiologic substances and may provide molecular bases for explaining how proteinuria is induced under pathologic situations and why some ligands for nuclear receptors have the anti-proteinuric potential.

Enhancement of NF-kappaB activity by resveratrol in cytokine-exposed mesangial cells

Resveratrol, a natural polyphenolic phytoalexin, has been considered as a potential anti-inflammatory agent because of its suppressive effect on nuclear factor-kappaB (NF-kappaB). However, we recently found that treatment of glomerular mesangial cells with resveratrol significantly and dose-dependently enhanced NF-kappaB activation triggered by proinflammatory cytokines. This finding was evidenced by different reporter assays as well as by expression of an endogenous NF-kappaB-dependent gene, intercellular adhesion molecule-1. The NF-kappaB promoting effect of resveratrol was also observed in renal tubular LLCPK1 cells, but not in HepG2 hepatoma cells. In all cell types tested, treatment with resveratrol alone did not affect NF-kappaB activity. The enhanced activation of NF-kappaB by resveratrol progressed for at least 24 h and was accompanied by sustained down-regulation of an endogenous NF-kappaB inhibitor, IkappaBbeta, but not IkappaBalpha. Although expression of inducible nitric oxide synthase was suppressed by resveratrol, nitric oxide, a negative regulator of NF-kappaB, was not involved in the regulation of NF-kappaB by resveratrol. These data elucidated, for the first time, that resveratrol may enhance activation of NF-kappaB under certain circumstances.

Hepatic portal venous gas associated with nonocclusive mesenteric ischemia in a hemodialysis patient

Hepatic portal venous gas (HPVG) has been rarely described in chronic hemodialysis patients. We report a case of HPVG in a 59-year-old female patient with hemodialysis-dependent chronic renal failure due to diabetes who presented with acute onset of abdominal pain. Abdominal CT demonstrated the presence of gas in the portal veins. However, on laparotomy, no evidence of bowel necrosis or perforation could be found. HPVG seemed to be caused by nonocclusive mesenteric ischemia (NOMI), an increasingly recognized complication in hemodialysis patients. The patient responded favorably to intravenous hyperalimentation and antibiotics.

Myocardial connections between left atrial myocardium and coronary sinus musculature in man

INTRODUCTION

Anatomic studies have shown that muscle morphologically identical to that of the atrial myocardium consistently surrounds the coronary sinus (CS). The CS musculature is connected to the left atrial (LA) myocardium in a variable fashion, with fewer connections in its distal portion. The aim of this study was to document the presence of connections between the LA myocardium and the CS musculature, using pacing maneuvers in man, and to study their potential association with natural atrial arrhythmia occurrence.

METHODS AND RESULTS

Thirty patients (19 men; mean age 50.5 years) underwent electrophysiologic study, during which a decapolar catheter with 2-mm interelectrode spacing every 10 mm was inserted into the CS, with the proximal electrode pair positioned at the ostium. Associated atrial arrhythmias were paroxysmal atrial fibrillation in 5, typical atrial flutter in 13, LA flutter in 1, and other in 11. Baseline S1 and a single extrastimulus were delivered during distal and proximal CS pacing, while recordings were obtained from the four remaining bipoles. During distal CS pacing, double potentials with increasing interpotential interval from proximal to distal CS as a function of extrastimulus prematurity were detected in nine patients, suggesting block in a discrete local pathway distally connecting the CS to the LA and leading to reversion of low LA activation. Local delay in this pathway without complete CS-LA block resulting in LA activation fusion was observed in eight patients. A single nonfractionated potential at the distal CS, even at the shortest attainable S1-S2 coupling interval, which was interpreted as no block within distal CS-LA connection(s), was observed in the other 13 patients. History of atrial fibrillation or atypical atrial flutter was found in 8 of 9 patients with block at the distal CS-LA connection but in only 3 of 13 patients with no CS-LA connection block (P = 0.004).

CONCLUSION

The ability to dissociate the LA from the distal CS suggests the presence of discrete connections between these structures in man. This observation appears to be associated with the clinical occurrence of atrial arrhythmias.

[Implementation and evaluation of public relations activity in a community health program]

OBJECTIVE

This study evaluated public relations activity in a community health program in order to develop effective strategies to attract the public attention for the program.

METHODS

An intervention study was conducted on public relations for "Nutrition Seminar for Citizens," sponsored by the Health Department of Machida City, Tokyo, in October, 1999. One ward in the city was selected as an intervention area, and another ward which had similar demographic and geographic characteristics was chosen as a control area. Two target populations were defined; one was women in their 20s to 60s (#1) and the other was those who had previously never utilized community health programs sponsored by the city (#2). Handbills were used as the medium for public relations for the seminar. These announced the time, place and content of the nutrition seminar and were designed by authors with special attention to catchphrases, colors and fonts. Handbills were distributed in the intervention area through elementary schools, local voluntary organizations and local health volunteers. In addition, the authors directly handed them out to people in front of two supermarkets in the town. The sources of seminar information were requested from the participants of the Nutrition Seminar with a self-administered questionnaire.

RESULTS

1. The percentage of participants who received the seminar information from handbills was higher than that of those who used monthly newsletters from the city as a source of information. 2. The percentage of participants from the intervention area was higher than that from the control area. 3. Regarding target populations #1 and #2, there were no differences in participation rates between the intervention and control area. 4. Among the four distribution routes, the local voluntary organization route was the most effective for attracting participants.

CONCLUSIONS

The results show that handbills can be an effective medium for pubic relations to increase the number of participants in community health programs. Also, local voluntary organizations can play a crucial role in information transfer in the community because of their high credibility. On the other hand, we could not reach specified target populations with the medium. Further surveys are needed to establish optimal media and routes to reach appropriate target populations in health programs.

Electrophysiological determinants of persistent dual atrioventricular nodal pathway physiology after slow pathway ablation in atrioventricular nodal reentrant tachycardia

The purpose of this study was to examine the electrophysiological determinants of the elimination of recurrent atrioventricular nodal reentrant tachycardia (AVNRT) despite the persistence of dual AV nodal pathway physiology or single echo beats after ablation procedures. The study included 26 patients with common AVNRT who had undergone successful ablation treatment and no long-term recurrence of AVNRT. The slow pathway potential was targeted, and the endpoint of ablation was one echo during atrial extrastimulus testing (ET) with isoproterenol. Persistent dual pathways physiology or single echoes were present in 12 patients (group I) and absent in 16 (group II) after ablation. The number of anterograde AV nodal pathways and maximum AH interval (Max AH) during ET were measured before and after ablation, and ventriculoatrial conduction during ventricular pacing was examined.

RESULTS

(1) multiple AV nodal pathways were more frequently observed in group I than in group II (50.0% vs 7%, P < 0.05); (2) Max AH decreased significantly after ablation in both groups (309 +/- 157 vs 171 +/- 53 ms in group II; P < 0.01, and 409 +/- 65 vs 274 +/- 86 ms in group I; P < 0.001); and (3) retrograde dual pathway conduction was more common in group I than in group II. These data suggest the presence of nonuniform conductive properties of the AV node in group I and that ablation targeting the slow pathway potential prevents recurrences of AVNRT by eliminating the pathway with the longest conduction time.

Comparison of effectiveness of an 8-mm versus a 4-mm tip electrode catheter for radiofrequency ablation of typical atrial flutter

An 8-mm catheter does not appear superior to 4-mm tip electrode for atrial flutter ablation. The potential advantage of allowing higher energy delivery on a larger surface is compensated by the lack of consistent contact with the endocardial surface.

Shortening of conduction time over arborized atrioventricular accessory pathway with Mahaim fibers physiology just before interruption during radiofrequency ablation

A 21-year-old woman had paroxysmal wide QRS tachycardia with a left bundle branch block configuration and a retrograde conducted P wave just behind the QRS complex. An electrophysiological study revealed antidromic atrioventricular tachycardia involving an atrioventricular connection with decremental conduction as the anterograde limb and normal atrioventricular node as the retrograde limb. During constant pacing from the high right atrium (HRA) at the cycle length (CL) of 600 ms, the QRS configurations were not identical to those during the wide QRS tachycardia or constant pacing at the CL of less than 500 ms. The process by which this arborized atrioventricular accessory pathway with the Mahaim fibers physiology was interrupted by radiofrequency catheter ablation is described. Radiofrequency energy was delivered to the site recording a Mahaim potential at the tricuspid annulus during constant pacing from the HRA at the CL of 429 ms. The stimulus-QRS interval gradually shortened as it reached the power plateau without changing the preexcited QRS configuration. Shortening of the conduction time over the Mahiam pathway might have resulted in changing of the propagation from a slow to fast conduction zone or acceleration in response to thermal effect in a node-like structure on the atrial insertion site.

[A case of metastatic liposarcoma originating in the retroperitoneum successfully treated with combination chemotherapy]

We reported a 36-year-old woman with metastatic liposarcoma originating in the retroperitoneum, which responded well to adjuvant chemotherapy. The primary tumor was removed by surgery. Two months later, the patient developed metastasis to the brain, and to the lung four months later. Metastatic liposarcomas to the brain generally are extremely rare. The patient was treated with combination chemotherapy using cyclophosphamide, vincristine, adriamycin, and dacarbazine (CYVADIC). After she was examined, the former two drugs were alternated with vindesine and ifosfamide, and another regimen with cisplatin and etoposide was given after a three-week interval. As a result, both of the metastases totally disappeared. No recurrent lesion has been noted for two years. Although the role of chemotherapy for liposarcoma has not been well defined and little data support its use in an adjuvant setting, this combination chemotherapy seemed to be effective for advanced liposarcoma.

Electrophysiological characteristics during slow pathway ablation of posterior atrioventricular junctional reentrant tachycardia

The purpose of this study was to compare the electrophysiological characteristics of posterior and anterior atrioventricular junctional reentrant tachycardia (AVJRT) during radiofrequency (RF) catheter ablation of a slow pathway. Twenty-four patients with common AVJRT, including 4 posterior (P) and 20 anterior AVJRT (A) were studied. We analyzed the retrograde atrial activation sequence of junctional rhythm and the presence of transient HA block during slow pathway ablation. When HA block developed, the AH interval before ablation and immediately after the end of energy delivery was measured. Successful ablation sites were divided into three groups; high (H), middle (M), and low (L) from the His bundle to the floor of the coronary sinus orifice. The results were: (1) the number of successful ablation sites were H 0, M 1, L 3 in P and H 1, M 8, L 11 in A; (2) the HA interval during AVJRT in P was longer than that in A (109 +/- 48 ms vs 43 +/- 6 ms, P < 0.01); (3) the retrograde atrial activation sequence during junctional rhythm was strictly concordant with that during AVJRT in both groups, but HA block developed during slow pathway ablation more often in P than in A (100% vs 30%, P < 0.01); and (4) The AH interval did not lengthen after HA block developed in P. These data suggest that another pathway does exist from the AV node to the atrium in addition to anterograde fast pathway and slow pathway, and that this pathway is used as the retrograde limb of P.

Effect of radiofrequency catheter ablation on parasympathetic denervation: a comparison of three different ablation sites

Radiofrequency (RF) catheter ablation of supraventricular tachycardias (SVT) has been shown to result in local parasympathetic denervation. The purpose of this study was to estimate the correlation between RF cumulative energy and parasympathetic denervation at three different ablation sites.

METHODS

45 patients who underwent RF ablation of 36 AV reentrant tachycardias and 9 AV nodal reentrant tachycardias were studied. Twenty patients had left free-wall accessory pathways (group L), 8 patients right free-wall accessory pathways (group R), and 17 patients septal accessory pathways (n = 8) or slow pathways (n = 9) (group S). Time and frequency domain analysis of heart rate variability on 24-hour ambulatory ECG recordings was performed before and after RF ablation. pNN50 and the high frequency (0.15 to 0.40 Hz, HF) component were measured to examine the effects on parasympathetic nerve activity. The values of delta pNN50 and delta HF were expressed as the percent change of pNN50 and HF that occurred after versus before RF ablation.

RESULTS

Both pNN50 and HF significantly decreased after RF ablation in all three groups. In group S, there was a significant correlation between RF cumulative energy and delta pNN50 (r = 0.66, P < 0.01) or delta HF (r = 0.58, P < 0.05). In contrast, there was no correlation between RF cumulative energy and delta pNN50 or delta HF in either group L or group R.

CONCLUSION

These data suggest that RF ablation produces parasympathetic denervation at all three sites along the mitral or tricuspid annulus and that parasympathetic fibers may be located predominantly in the septal area.

Exercise-induced coronary spasm: comparison of treadmill and bicycle exercise in patients with vasospastic angina

BACKGROUND

We investigated whether exercise-induced coronary spasms are influenced by the different exercise modes.

METHODS

We compared ischaemic ECG responses in 67 patients with vasospastic angina who underwent both treadmill and bicycle ergometer exercise and also coronary angiography.

RESULTS

ECG ST-segment elevation was provoked more frequently during treadmill exercise than it was during bicycle exercise (19 versus 9%, P < 0.05). Of 45 patients without significant coronary stenosis (coronary artery luminal diameter narrowing < 75%), 19 patients manifested ST-segment depression during treadmill exercise, whereas only seven patients did during bicycle exercise (42 versus 16%, P < 0.01). All patients with ST-segment elevation or depression during bicycle ergometer exercise also had ST-segment changes during treadmill exercise. Although higher systemic blood pressure levels and lower heart rates were found during bicycle exercise compared with during treadmill exercise the pressure-rate products at peak exercise did not differ between the two exercise tests.

CONCLUSIONS

It seems that treadmill and bicycle exercise are different stressors in patients with vasospastic angina, and that coronary spasms are provoked more frequently during treadmill exercise than they are during bicycle exercise. The cause of this difference is not known, but it may be related in part to the difference in systemic haemodynamic or neurohumoral response.

[MR diffusion-weighted imaging of cerebral infarction]

MR diffusion-weighted imaging was performed to investigate changes in water diffusion in patients with cerebral infarction, and diffusion-weighted images (DWI) were compared with T2-weighted images (T2WI). Acute and subacute infarcts were seen as areas of high intensity on DWI and showed lower apparent diffusion coefficients (ADCs), while chronic infarcts showed a relative increase in ADCs. The relative ADC increased progressively over time, becoming renormalized at 3 to 4 weeks, and was elevated in the chronic state. On DWI, infarcts as small as 5 to 6 mm in diameter and lesions adjacent to the ventricular or subarachnoid space could be readily identified. DWI was useful for distinguishing acute lesions from chronic lesions in patients with multiple cerebral infarction, and provided valuable pathophysiologic information on the course of ischemic stroke evolution.

Exclusive anti-Stokes Raman scattering using coherent material excitation

A new process capable of scattering intense anti-Stokes waves that uses stimulated electronic Raman scattering in metal vapor is proposed. The coherent material excitation produced by a prepump pulse couples with the forthcoming main pulse exclusively to create polarization that radiates the anti-Stokes wave. The selection rule governed by angular momentum conservation is the key to cause such strong coupling to induce unidirectional upconversion without any population inversion. The power conversion efficiency from the pump wave to the anti-Stokes wave is theoretically expected to reach 100% in this process.

[Acute and chronic effects of a new oral inotropic agent, ibopamine hydrochloride, on hemodynamic and metabolic responses to ergometer exercise in patients with severe congestive heart failure]

The hemodynamic and metabolic effects of ibopamine, an orally active 3,4-diisobutylic ester of N-methyl-dopamine, at rest and during exercise, were evaluated in 8 patients with severe congestive heart failure, initially at 2 hrs after oral 100 mg and after 4 weeks of maintenance therapy (100 mg, 3 times a day). At rest, a single dose of ibopamine increased CI, SVI and SWI, and reduced PCWP, PAm, RA and PVR. These beneficial hemodynamic effects were maintained during supine bicycle exercise: CI and SVI increased markedly (p less than 0.05) and PCWP, PAm, RA and SVR increased at a lower extent (p less than 0.05) after ibopamine than on control conditions. After chronic therapy with the drug, LVDd and CTR decreased (p less than 0.05) and exercise tolerance time increased (p less than 0.01). HR, BPm, double product, norepinephrine, epinephrine, renin activity, aldosterone and lactate/pyruvate did not change significantly after administration of ibopamine. Clinical responses after 4 weeks of maintenance therapy were good in 4 cases and fair in 1 case. No adverse effects were observed. Therefore, ibopamine seems to have not only a positive inotropic action, but also a potent vasodilating action, leading to both afterload and preload reduction and so to be useful for the treatment of severe congestive heart failure at rest and during exercise after acute and chronic therapy with the drug.

Novel method for the preparation of controlled-release theophylline granules coated with a polyelectrolyte complex of sodium polyphosphate-chitosan

A novel method for the preparation of theophylline granules coated with a polyelectrolyte complex of sodium tripolyphosphate and chitosan was developed. The theophylline granules containing sodium tripolyphosphate were stirred in an HCl solution of chitosan. During the mixing, the dissolved sodium tripolyphosphate in the granule moved to the surface and reacted with the chitosan, resulting in the formation of the polyelectrolyte complex film. The factors affecting the drug content, the particle size, and the coating-film thickness of the resultant coated granules were determined. The theophylline content in the coated granule decreased with increasing content ratio of sodium tripolyphosphate to theophylline in the original granule and with increasing chitosan concentration in the coating solution. The coated granule size increased with increasing chitosan concentration in the coating solution and with decreasing agitation speed. The coating-film thickness increased with an increase in the chitosan concentration, the pH of the coating solution, and the sodium tripolyphosphate to theophylline content ratio in the original granule. The drug-release pattern of the coated granules followed zero-order kinetics and the release rates were significantly reduced compared with that of the original granule.

[Measurement of 222Rn in air using liquid scintillation techniques (author's transl)]

A simple method for the measurement of 222Rn in air was established. At first step radon daughters in air were eliminated from air by suction using glass fiber filter, after that the air were introduced directly to the scrubbing bottle filled with scintillator based on toluene and bubbled until the concentration of 222Rn in the liquid scintillator reached equilibrium state. Then 120ml of the bubbled liquid scintillator were sealed in the teflon vial for the measurement of radioactivity. After the radioactive equilibrium between 222Rn and its daughters were reached, the radioactivity were measured by the low background liquid scintillation counter. The detection limit of 222Rn in air by this method was 3 x 10(-3) Bq/l air (8 x 10(-14)Ci/l air). Though alpha spectrometry by multi-channel analyzer was also achieved, the integral counting method was used more effectively. This method was effectively applied to determine the relatively high concentration of 222Rn in air.

[Studies on toxicity of hydrocortisone 17-butyrate 21-propionate -4. Chronic toxicity in rats by subcutaneous administration (author's transl)]

Chronic toxicity of hydrocortisone 17-butyrate 21-propionate (HBP), a new synthetic corticosteroid, was studied in rats. HBP was subcutaneously injected to rats as the daily doses of 0.001, 0.01, 0.01, 1.0 and 3.0 mg/kg for 6 months, and the following recovery test was carried out for 4 weeks. Hydrocortisone 17-butyrate (HB) and betamethasone 17-valerate (BV) were used as the reference drugs at the doses of 0.1, 1.0 and 3.0 mg/kg. The suppression of body weight gain by the administration of HBP was observed at the doses more than 1.0 mg/kg in male and more than 0.1 mg/kg in female, and the dead animals were sent at the highest dose of HB and BV. Mainly at the doses more than 0.1 mg/kg HBP induced the dose-dependent symptoms such as decrease in the number of white blood cells and total protein level in serum, and increase in total cholesterol, GOT and GPT level in serum, and atrophic changes of adrenals, lymphatic tissues, skin and subsexual organs. No usual abnormality was recognized at the doses less than 0.01 mg/kg of HBP. These symptoms were more toxic in male, and the strength of toxicity was in the order of BV greater than HB greater than HBP. Many of these findings have known as common effects of corticosteroids. The changes observed in this study were almost recovered after withdrawal of HBP at the doses less than 0.1 mg/kg. As the result, it was suggested that the maximum non-toxic dose of HBP was 0.001 mg/kg.