Vagal reflex provoked by radiofrequency catheter ablation in the right aortic sinus cusp: a Bezold–Jarisch-like phenomenon

A 66-year-old woman with idiopathic premature ventricular contractions with a left bundle branch block QRS morphology and left inferior axis underwent electrophysiologic testing. Successful radiofrequency ablation was achieved in the right coronary cusp (RCC). However, radiofrequency ablation at sites adjacent to the successful ablation site provoked sinus bradycardia followed by atrioventricular conduction block. That phenomenon might be explained by a vagal reflex through stimulation of vagal pathways or receptors in the anterior epicardial fat pads neighboring to the RCC. A vagal reflex should be kept in mind as a complication during catheter ablation of ventricular arrhythmias originating from the RCC.     

Covalent immobilization of chitosan derivatives onto polymeric film surfaces with the use of a photosensitive hetero-bifunctional crosslinking reagent

Partially N-acetylated chitosan was covalently immobilized onto polymeric film surfaces using the photosensitive hetero-bifunctional crosslinking reagent, methyl 4-azidobenzoimidate, which was previously attached to the chitosan by the reaction between an imidoester group of the reagent and a free amino group of the chitosan. The grafting was accomplished by irradiating with ultraviolet light the modified chitosan being coated on the film surfaces to photolyse arylazide groups, thus crosslinking the chitosan and the underlying substrate polymer together. For ultraviolet absorption and infrared spectroscopy, the irradiation time of 3 min was found to be sufficient for the photolysis of the azide group. The thickness of the immobilized chitosan layer was estimated to be of the order of 30–150 nm using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The chitosan molecules immobilized on the surfaces could be chemically modified by several reagents and also treated with a heparin solution to form a polyelectrolyte complex on the surface. The ionically bound heparin was partially released into a phosphate buffer solution.     

Histamine synthesis is required for granule maturation in murine mast cells

Mast cells are the major sources of histamine, which is released in response to immunological stimulations. The synthesis of histamine is catalyzed by histidine decarboxylase (HDC). Previous studies have shown that Hdc^?/? mast cells exhibit aberrant granule morphology with severely decreased granule content. Here, we investigated whether the histamine synthesized in mast cells regulates the granule maturation of murine mast cells. Several genes, including those encoding granule proteases and enzymes involved in heparin biosynthesis, were downregulated in Hdc^?/? peritoneal mast cells. Impaired granule maturation was also found in Hdc^?/? BM‐derived cultured mast cells when they were cocultured with fibroblasts in the presence of c‐kit ligand. Exogenous application of histamine and several H₄ receptor agonists restored the granule maturation of Hdc^?/? cultured mast cells. However, the maturation of granules was largely normal in Hrh4^?/? peritoneal mast cells. Depletion of cellular histamine with tetrabenazine, an inhibitor of vesicular monoamine transporter‐2, did not affect granule maturation. In vivo experiments with mast cell deficient Kit^W/Kit^W‐v mice indicated that the expression of the Hdc gene in mast cells is required for granule maturation. These results suggest that histamine promotes granule maturation in mast cells and acts as an proinflammatory mediator.     

Effects of etizolam and ethyl loflazepate on the P300 event-related potential in healthy subjects

Background

Benzodiazepines carry the risk of inducing cognitive impairments, which may go unnoticed while profoundly disturbing social activity. Furthermore, these impairments are partly associated with the elimination half-life (EH) of the substance from the body. The object of the present study was to examine the effects of etizolam and ethyl loflazepate, with EHs of 6 h and 122 h, respectively, on information processing in healthy subjects.

Methods

Healthy people were administered etizolam and ethyl loflazepate acutely and subchronically (14 days). The auditory P300 event-related potential and the neuropsychological batteries described below were employed to assess the effects of drugs on cognition. The P300 event-related potential was recorded before and after drug treatments. The digit symbol test, trail making test, digit span test and verbal paired associates test were administered to examine mental slowing and memory functioning.

Results

Acute administration of drugs caused prolongation in P300 latency and reduction in P300 amplitude. Etizolam caused a statistically significant prolongation in P300 latency compared to ethyl loflazepate. Furthermore, subchronic administration of etizolam, but not ethyl loflazepate, still caused a weak prolongation in P300 latency. In contrast, neuropsychological tests showed no difference.

Conclusions

The results indicate that acute administration of ethyl loflazepate induces less effect on P300 latency than etizolam.     

Sentinel lymph nodes in endometrial cancer: is hysteroscopic injection valid?

We aimed to describe hysteroscopic peritumoral tracer injection for detecting sentinel lymph nodes (SLNs) in patients with endometrial cancer and to evaluate tolerance of the procedure, detection rate and location of SLNs. Five patients with early endometrial cancer underwent hysteroscopic radiotracer injection followed by lymphoscintigraphy, then by surgery with hysteroscopic peritumoral blue dye injection, and radioactivity measurement using an endoscopic handheld gamma probe. SLNs and other nodes were sent separately to the pathology laboratory. SLNs were evaluated by hematoxylin-eosin-saffron staining and, when negative, by immunohistochemistry. Tolerance of the injection by the patients was poor (mean visual analog scale score, 8/10). SLNs were detected in only two patients (external iliac and common iliac+paraaortic, respectively). Detection rates were 1/5 by radiotracer, 1/5 by dye, and 2/5 by the combined method. One SLN was involved in a patient whose other nodes were negative. In three patients no SLNs were found by radiotracer or blue dye. Of the 83 non sentinel nodes removed from these patients, none was involved. Hysteroscopic peritumoral injection may be more difficult than cervical injection and, in our experience, carries a lower SLN detection rate.     

Difference of osteopontin gene regulation between bone and kidney

 Osteopontin is a sialoprotein that is expressed in various cells. It plays a variety of important roles in cell adhesion, migration, signaling, calcification, and immunity. Its diverse functions indicate that the regulation of osteopontin may also vary extensively among tissues. Although osteopontin promoter has been studied in vitro, in vivo analyses may be more appropriate for elucidating osteopontin's functions. In an attempt to investigate osteopontin gene expression, we generated transgenic mice in which the bacterial β-galactosidase reporter gene was conjugated downstream of osteopontin promoter. The osteopontin promoter was a mouse −910 bp upstream fragment, which we had previously found functional in 3T3 cells. Among 34 transgenic founders, 13 mice were transgenic, as determined with the polymerase chain reaction. Osteopontin and β-galactosidase signals were evaluated with in situ hybridization. Among the 13 transgenic mice, 3 were β-galactosidase-positive. In these transgenic mice, osteopontin signals were observed in bones and kidneys, whereas β-galactosidase message was detected only in bones. This suggests that the −910 bp osteopontin promoter is active in bones but not in kidneys. These data imply that the promoter region required for osteopontin expression in kidneys may differ from that in bones. Received: March 22, 2002 / Accepted: December 5, 2002 RID="*" ID="*" Offprint requests to: T. Sakuma Acknowledgments. We greatly appreciate the excellent histotechnological assistance of Mr. Kenji Morihana. This work was supported in part by a grant from The Ministry of Education, Science, and Culture, Japan (no. 12470056).     

Analysis of the arterial blood pressure waveform using Fast Fourier Transform technique during left ventricular nonpulsatile assistance: in vitro study

The arterial blood pressure waveform is variable during left ventricular assistance. The aim of this study is to examine the correlation between the left ventricular assist device (LVAD) condition and the arterial blood pressure waveform in a fixed cardiac output condition using a mock circuit. This mock circulation loop was composed of an aortic compliance chamber, a left atrial compliance chamber, a pneumatic pulsatile pump as a native heart, and a rotary blood pump representing the LVAD with left atrial drainage. The Fast Fourier Transform technique was utilized to analyze the arterial blood pressure waveform and calculate the pulsatility index (PI) and the pulse power index (PPI). The PI and PPI decreased with the increase of the LVAD rotational speed, exponentially. There was a significant negative correlation between the PI, PPI, and the LVAD rotational speed, flow rate, and assist ratio. The best correlation was observed between the PPI and the assist ratio (r = 0.986). From this viewpoint, an ideal LVAD condition may be estimated from the pulsatility change of the arterial blood pressure waveform.     

A case of graft replacement of the ascending aorta to the aortic arch and the partial descending aorta in a single stage for thrombosed aortic dissection (debakey type II + IIIB)

We report here a case of graft replacement of the ascending aorta to the aortic arch and the middle portion of the descending aorta in a single stage for thrombosed aortic dissection. The patient was a 53-year-old male who was transfered to our hospital with a diagnosis of thrombosed aortic dissection. Conservative therapy was continued but three weeks after the onset, chest enhanced CT scan and digital subtraction angiography revealed an opacified false lumen in the ascending aorta and a ulcer like projection in the middle portion of the descending aorta. He was therefore diagnosed as having redissection in DeBakey type II + IIIb thrombosed aortic dissec- tion. Graft replacement of the ascending aorta, the aortic arch, and a part of the descending aorta was performed in a single stage via median stenotomy with the aid of extracorporeal circulation and selective cerebral perfusion. Postoperative digital subtraction angiography showd satisfac- tory reconstruction of the thoracic aorta. The patient is still leading a normal life two years after the operation.