Sensitivity to a CD4 mimic of a consensus clone of monkey-adapted CCR5-tropic SHIV-MK38C

By acclimatizing CCR5-tropic tier 1B SHIV-MK1 to rhesus monkeys, a tier 2 SHIV-MK38 strain with neutralization resistance and high replication ability was generated. In this study, we generated SHIV-MK38C, a monkey-infectious consensus molecular clone of SHIV-MK38. Analysis using pseudotype viruses showed that MK38C was tier 1C because it lacked the N169D mutation, which is the most important mutation for neutralization resistance. MK38C harboring the N169D mutation became tier 2. However, the replication ability of SHIV-MK38C with N169D was low; more than 17 weeks elapsed before its detection in monkeys. Tier 1C MK38C was sensitive to a CD4 mimic. Therefore, SHIV-MK38C could be used to evaluate CD4 mimics in vivo.

Inhibition of NADPH oxidase 4 activates apoptosis via the AKT/apoptosis signal-regulating kinase 1 pathway in pancreatic cancer PANC-1 cells

Pancreatic adenocarcinoma is an aggressive human malignancy and is characterized by resistance to apoptosis. Recently, NADPH oxidase (Nox) 4-mediated generation of intracellular reactive oxygen species (ROS) was proposed to confer antiapoptotic activity and thus a growth advantage to pancreatic cancer cells. The signaling mechanism by which Nox4 transmits cell survival signals remains unclear. Here, we show that both a flavoprotein inhibitor, diphenylene iodonium (DPI), and small interfering RNAs designed to target Nox4 mRNA (siNox4RNAs) inhibited superoxide production in PANC-1 pancreatic cancer cells, and depletion of ROS by DPI or siNox4RNAs induced apoptosis. Parallely, DPI treatment and siNox4RNA transfection blocked activation of the cell survival kinase AKT by attenuating phosphorylation of AKT. Furthermore, AKT phosphorylation of apoptosis signal-regulating kinase 1 (ASK1) on Ser-83 was reduced by DPI and siNox4RNAs. When ASK1Ser83Ala (an AKT phosphorylation-defective ASK1 mutant) was introduced into PANC-1 cells, this mutant alone induced apoptosis. But, addition of DPI or co-transfection of siNox4RNA had no additive effect, indicating that the mutant can substitute for these reagents in apoptosis induction. Taken together, these findings suggest that ROS generated by Nox4, at least in part, transmit cell survival signals through the AKT-ASK1 pathway in pancreatic cancer cells and their depletion leads to apoptosis.

Quantification and detection of bacteria from postoperative maxillary cyst by polymerase chain reaction

BACKGROUND/AIMS

Postoperative maxillary cyst (POMC) is known to occur as a delayed complication of radical maxillary sinus surgery, such as Caldwell-Luc surgery. The cyst gradually expands with no symptoms over a period of years, and then occasionally causes swelling and pain in the buccal region and/or the mucogingival fold. It is probable that bacterial infection affects the progression of POMC symptoms. The aims of this study were to determine the bacterial density and to examine the presence of 20 oral bacteria in POMC fluids.

METHODS

POMC fluids (4 purulent, 2 mucous and 4 serous) were sampled from 10 subjects (aged 43-77 years). Bacterial quantification and detection were performed by real-time polymerase chain reaction (PCR) and nested PCR based on bacterial 16S rRNA genes, respectively.

RESULTS

Bacterial DNA was detected in all samples and the average concentrations of bacterial DNA were 5.9 (purulent), 0.5 (mucous), and 0.7 (serous) ng/mg of sample. Twelve bacterial species, including anginosus streptococci, known to be associated with abscess formation, were detected in the purulent fluids, while two and five species were detected in the mucous and serous fluids, respectively.

CONCLUSION

Purulent fluids contained numerous bacteria of various types, thus suggesting that oral bacteria may cause symptoms such as pain in POMC with purulent fluids. Mucous and serous fluids also contained bacteria, although their numbers were small, thus suggesting an association between bacteria and progression of POMC.

Identification of mutans streptococci by restriction fragment length polymorphism analysis of polymerase chain reaction-amplified 16S ribosomal RNA genes

Mutans streptococci are frequently isolated from dental plaque and carious lesions. These bacteria have been identified by conventional methods such as biochemical and serologic tests followed by the isolation of colonies on the mitis-salivarius agar, which are sometimes inconsistent. Recently, species-specific polymerase chain reaction (PCR) has been reported to rapidly identify Streptococcus mutans and Streptococcus sobrinus. However, in the case of identification and classification into several species, e.g. within the group of mutans streptococci consisting of seven species, the identification using species-specific PCR seems somewhat inefficient because of need for the development and preparation of specific primers for each species. Therefore, in this study we developed a simple method using restriction fragment length polymorphism analysis of PCR-amplified 16S ribosomal RNA genes (16S rRNA genes PCR-RFLP) for the identification of seven different species included in the group of mutans streptococci. We amplified 16S rRNA gene sequences from genomic DNA samples by PCR using universal primers and digested the PCR products with the restriction endonucleases, HpaII and HaeIII. HpaII produced six RFLP patterns for eight reference strains, since the patterns for S. sobrinus, Streptococcus downei and Streptococcus ferus were similar. RFLP patterns produced with HaeIII could separate these three species. Furthermore, the RFLP patterns predicted from the 16S rRNA gene sequences in the GenBank database agreed with the actual RFLP patterns produced in the present study. The 16S rRNA sequence comparisons can be used to identify oral mutans streptococci; however, the identification by sequencing is sometimes difficult in large-scale studies and for small laboratories. Therefore, 16S rRNA genes PCR-RFLP, using HpaII and HaeIII, could be an alternative method for the identification of mutans streptococci, and may be applicable for large-scale studies on the cariogenicity of mutans streptococci.

Nested PCR for detection of mutans streptococci in dental plaque

AIMS

Mutans streptococci such as Streptococcus mutans and Streptococcus sobrinus have been implicated in human dental caries. In an attempt to develop a rapid and sensitive method for detecting Strep. mutans and Strep. sobrinus in dental plaque, a nested PCR amplification based on the 16S rRNA gene was employed.

METHODS AND RESULTS

A universal set of PCR primers for bacterial 16S rRNA gene was introduced for the first PCR, and then two sets of primers specific for the 16S rRNA gene sequences of either Strep. mutans or Strep. sobrinus were used for the second PCR. Eighteen plaque samples were analyzed, and a nested PCR was shown to be more sensitive for detecting Strep. mutans and Strep. sobrinus than direct PCR.

CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY

The 16S rRNA gene-based nested PCR method is a rapid and sensitive method for the detection of mutans streptococci, and may also be suitable for carrying out large-scale studies on the cariogenicity of mutans streptococci.

Lack of association between lumbar disc degeneration and osteophyte formation in elderly japanese women with back pain

Our study was designed to assess the contributions of the physical and constitutional factors to osteophyte formation, disc degeneration, and bone mineral density (BMD) in lumbar vertebrae of elderly postmenopausal women. A total of 126 Japanese women with back pain, aged over 60 years, were invited to participate in the study. Then 80 subjects with a full set of data for physical examinations, radiographs, MRI, and DXA were examined. TaqI polymorphism of vitamin D receptor (VDR) gene was examined in 60 subjects. Prevalence rates of osteophytes (on radiographs) and disc degeneration (on MRI) were 61 and 68%, respectively. Body weight and BMI correlated significantly with anteroposterior (AP) and lateral (LAT) BMD (r = 0.354 for weight, r = 0.347 for BMI) and mean osteophyte area (r = 0.557 for weight, r = 0.486 for BMI), and body weight also correlated with number of discs with osteophytes. However, these did not correlate with the disc area or the number of degenerated discs. Stepwise regression analysis revealed that body weight and LAT-BMD values independently related to the osteophyte area. Disc area (r = 0.386 for AP view) and osteophyte area (r = 0.384 for AP view) significantly correlated with BMD. However, disc area and osteophyte area did not correlate with each other (r = 0.056). The proportion of degenerated discs was higher in the lower lumbar discs, but not the proportion of discs with osteophytes. Frequencies of T and t alleles of VDR did not correlate with disc degeneration, osteophyte formation, or osteoporosis. Our data showed that increases in osteophyte formation and BMD in the lumbar vertebrae are influenced by body weight and BMI, but did not correlate with disc area, which correlated inversely with BMD. Disc degeneration and osteophyte formation seem to represent two different factors that affect lumbar spine in elderly women.

Th1/Th2 balance alteration in the clinical course of a patient with acute viral myocarditis

Cytokines have an important role in the pathogenesis and pathophysiology of myocarditis. In this study, subsets of peripheral helper T lymphocytes (Th) in a patient with acute viral myocarditis were analyzed by 3-color flow cytometry. During the clinical course of myocarditis, the Th1/Th2 ratio of peripheral lymphocytes changed. Th1 was dominant in the acute inflammatory phase during which levels of creatine kinase (CK) increased (day 6), then Th2 levels overtook those of Th1 in the recovery phase during which levels of CK decreased (day 13 and 20). At the time of discharge (day 35), Th1 and Th2 had normalized. Thus, it was speculated that the induction of lymphocytic myocarditis was associated with Th1 dominant status, and recovery was related to Th2 polarity. Th subset imbalances may play an important role in the pathogenesis of acute viral myocarditis and these analyses may be useful for understanding the disease activity of myocarditis.

Abrupt loss of constant fusion during entrainment of ventricular tachycardia at a critical paced cycle length

Sustained monomorphic ventricular tachycardia (VT) can be frequently entrained and interrupted with rapid pacing and the mechanism of the pacing-induced interruption is considered to be due to orthodromic block. This study focused on the incidence of VT which was interrupted at a critical cycle length and was characterized by an abrupt loss of constant fusion in the surface electrocardiogram (ECG), and the role of orthodromic block as the cause of such characteristic change and interruption of VT was analyzed. Among 45 consecutive patients with symptomatic VT, rapid pacing was performed in 43 VTs of 39 patients. The exit was mapped as the earliest site of the activation during VT and an electrode catheter was located at the site. Rapid pacing was performed at progressively shorter cycle lengths in steps of 10 msec until VT was interrupted and the timing of the orthodromic and direct capture was compared at the exit. Abrupt loss of constant fusion was observed in 25 of 39 patients (64.1%): and the loss was invariably associated with interruption of VT. When the timings of the activation of the exit were compared, which were measured from the preceding (n-1) stimulus as the time reference, the direct capture was relatively delayed compared to that of the orthodromic capture. This finding suggests that orthodromic block is the cause of the direct capture as well as the pacing-induced interruption of VT. In the remaining 13 patients (35.9%), the surface ECG showed a gradual transition into the fully paced QRS morphology. The direct capture was confirmed in the non-fused beats, but it was not necessarily associated with interruption of VT. The interval from the stimulus to the entrained electrogram at the exit showed a gradual prolongation until the exit was finally captured directly from the pacing site. The confirmation of constant fusion followed by abrupt loss in ECG can be a reliable hallmark of orthodromic block as the cause of the interruption of VT during transient entrainment at a critical paced cycle length.

Triterpene alcohol and sterol ferulates from rice bran and their anti-inflammatory effects

Six novel feruloyl esters of triterpene alcohols and sterols, viz., two trans-ferulates, cycloeucalenol and 24-methylenecholesterol trans-ferulates, and four cis-ferulates, cycloartenol, 24-methyelenecycloartanol, 24-methylcholesterol, and sitosterol cis-ferulates, besides five known trans-ferulates, cycloartenol (CAR), 24-methylenecycloartanol (24-MCA), 24-methylcholesterol, sitosterol, and stigmastanol trans-ferulates, and one known cis-ferulate, stigmastanol cis-ferulate, were isolated from the methanol extract of edible rice bran. These and eight other synthetic trans- and cis-ferulates of triterpene alcohols and sterols, along with the corresponding free alcohols, were evaluated with respect to their anti-inflammatory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation (1 microg per ear) in mice. All of the ferulates showed marked inhibitory activity, and their 50% inhibitory dose (ID(50)) was 0. 1-0.8 mg per ear. On the other hand, whereas two free triterpene alcohols, CAR and 24-MCA, showed strong inhibition (ID(50) 0.2-0.3 mg/ear), eight free sterols examined showed weaker activity (ID(50) 0.7-2.7 mg/ear) than their corresponding ferulates.

Expression of coxsackievirus and adenovirus receptor in hearts of rats with experimental autoimmune myocarditis

The expression of coxsackievirus and adenovirus receptor (CAR) was dominant in the brains and hearts of mice until the newborn phase. There is no detailed information concerning the relation between the expression of CAR and development of hearts. It is also uncertain whether CAR is able to be induced in adult hearts after cardiac injury. We demonstrated that CAR was abundant in the hearts of newborn rats but was barely detectable in the hearts of adult rats. The expression of CAR in rat hearts with experimental autoimmune myocarditis, which was induced by immunization of purified cardiac myosin, was serially investigated. Active myocarditis was observed from day 15 after immunization. By immunohistochemistry, cardiomyocytes were strongly stained for CAR antibody from days 24 to 42. CAR mRNA was also detected from days 18 to 30 by using reverse transcription-polymerase chain reaction. In the next experiment, the induction of CAR on isolated cardiomyocytes was investigated. CAR was barely detectable in cultured cardiomyocytes by Western blot analysis after isolation. This molecule gradually appeared along with the creation of clusters and beating of cardiomyocytes. Furthermore, the induction of CAR in cultured cardiomyocytes increased after supplement with conditioned medium of rat splenocytes activated by concanavalin A. In conclusion, rat CAR is expressed strongly in the hearts of newborn rats and is suppressed in those of adult rats. The expression of CAR is enhanced during the active phase of experimental autoimmune myocarditis and is induced by inflammatory mediators. CAR may play a role in cell-to-cell contact and adhesion of cardiomyocytes.

Recovery of the right atrial effective refractory period after cardioversion of chronic atrial fibrillation

The effective refractory period was shorter in patients with than without chronic atrial fibrillation (AF). The effective refractory period was prolonged, and at 12 and 24 hours after cardioversion of AF it was the same as the subjects without AF.

Electrophysiologic parameters to predict clinical recurrence of ventricular tachycardia in patients under electrophysiologic study-guided effective pharmacological therapy

Although an electrophysiologic study (EPS) is the most reliable method for selecting the treatment for a patient with sustained ventricular tachycardia (VT), VT recurrence may occur even during EPS-guided effective therapy. Electrophysiologic parameters were compared between patients with and without arrhythmic events under EPS-guided effective therapy to identify the predictive parameters of VT recurrence during the clinical course. The study population consisted of 77 consecutive patients with sustained VT who were receiving long-term pharmacological therapy that was demonstrated to be effective by the EPS assessment. The VT induction protocol employed 1-3 extrastimuli and rapid ventricular pacing at 2 right ventricular sites and 1 left ventricular site, and isoproterenol was infused when VT was not induced. To determine the 'effective' antiarrhythmic drug, all sustained ventricular arrhythmias had to be prevented during the whole induction protocol, but repetitive ventricular responses (RVR) were allowed to remain for up to 5 beats when they were in the same QRS configurations as the clinical VT and up to 12 beats when they were in polymorphic QRS configurations. The effective refractory periods (ERPs) at the 3 ventricular pacing sites and their difference (i.e., ERP-dispersion) and the maximum number of RVR beats were evaluated in an EPS during the control state and at the time of drug assessment. In the comparison of patients with and without VT recurrence, there was no significant difference in clinical characteristics or ERPs, but the deltaERP-dispersion (i.e., the increase in ERP-dispersion caused by the antiarrhythmic drug) and the maximum number of RVRs were significantly smaller in the group of patients without VT recurrence (deltaERP-dis, -3+/-8 vs. 6+/-12, p = 0.0027; maxRVR, 3+/-3 vs. 5+/-4, p = 0.0160). The VT recurrence rate was significantly lower in the patients with deltaERP-dis < or =0 or maxRVR<6 in comparison with the others (p = 0.01 14 and p = 0.0360). Patients with VT recurrence showed greater deltaERP-disp and a longer duration of RVRs at the time of drug assessment in comparison with the patients without VT recurrence. The prognosis of patients under EPS-guided therapy may be improved by the use of stricter criteria for drug assessment in the EPS, although this may decrease the number of drug responders determined in the EPS.

Importance of retrograde atrial activation in atrial fibrillation genesis in the initiation of atrial fibrillation in Wolff-Parkinson-White syndrome. Comparison of atrial electrophysiologic parameters between patients with different atrial fibrillation genesis (initiation sites) in atria

The changes in the duration of atrial electrograms during different atrial activation sequences from a sinus rhythm were evaluated to test the hypothesis that the prolongation of atrial electrogram duration caused by the different atrial activation sequence is more prominent at the site of atrial fibrillation (Afib) genesis (initiation site) than other areas. In 39 patients with single retrograde left-sided accessory connection who had inducible transient atrial fibrillation during an electrophysiologic study, the site of Afib genesis was determined and classified into three groups, i.e., 1) high right atrial genesis (HRA), 2) low right atrial genesis (LRA), and 3) left atrial genesis (LA). Single premature extrastimuli after 8 basic drive trains (600 ms) were delivered at the HRA and the right ventricular apex. Three atrial electrophysiologic parameters were evaluated at three atrial sites, i.e., 1) HRA, 2) LRA, and 3) coronary sinus. The atrial vulnerability parameters were as follows; 1) %A2/A1: % prolongation of atrial electrogram duration during premature beat (A2) in comparison with basic drive (A1), 2) wavelength index (WLI): calculated as [effective refractory period]/[A2], and 3) retrograde activation index (RAI): calculated as [A1 during retrograde activation; i.e., RVA pacing/[A1 during antegrade activation, i.e., HRA pacing], shown as a percentage. The Afib genesis was HRA in 20, LRA in 12 and LA in 7 patients. At the HRA recording site, %A2/A1 and RAI were the largest and WLI the shortest in the HRA genesis group in comparison with the other two groups. Similarly, at the LRA and LA recording sites, %A2/A1 and RAI were the largest and WLI the shortest in the groups with Afib genesis at these recording sites. In patients with inducible Afib, %A2/A1 and RAI were the highest and WLI the shortest at the atrial recording site close to the site of Afib genesis. Atrial wave prolongation during retrograde atrial activation, possibly the anisotropic conduction, was considered to play a role in initiating Afib as well as a conduction delay during the atrial premature beat.

Effect of atropine on QT prolongation and torsade de pointes induced by intracoronary acetylcholine in the long QT syndrome

We recently reported a marked QT prolongation and torsade de pointes (TDP) induced by an intracoronary acetylcholine (ACh) administration in patients with long QT syndrome, but the mechanism was not determined. In the present study, the effect of atropine on the ACh-induced QT prolongation and TDP was studied in long QT syndrome. Nine patients with congenital long QT syndrome were studied. ACh at doses of 20, 50, and 100 microg were injected in a stepwise manner into the left main coronary artery, and the changes in the QT interval were measured. In 4 of the 9 patients, ACh administration at a dose of 100 microg was repeated after an intravenous atropine administration at a dose of 0.5 mg. The QT intervals were measured using 12-lead electrocardiograms, and the data were compared before and after atropine administration. The coronary angiograms were normal and coronary spasm was not induced by ACh in all patients. The intracoronary administration of ACh at a dose of 100 microg significantly prolonged the corrected QT interval (QTc), from 511 +/- 26 to 629 +/- 40 ms (p <0.05). In 5 of the 9 patients, TDP was induced and was spontaneously terminated within 10 seconds (n = 4) or required direct-current shock (n = 1). After atropine administration, intracoronary ACh at the same dose resulted in no QT prolongation, and the QTc interval remained unchanged (525 +/- 29 vs 520 +/- 21 ms before and after atropine), and no TDP was induced. These findings indicate that the muscarinic receptor is involved in ACh-induced QT prolongation and TDP, both of which were prevented by the atropine administration.

Elevated serum lipoprotein(a) is a risk factor for left atrial thrombus in patients with chronic atrial fibrillation: a transesophageal echocardiographic study

BACKGROUND

Patients with chronic atrial fibrillation have an increased risk of thromboembolism. Apoprotein(a) has a structural homology with plasminogen, suggesting that lipoprotein(a) [Lp(a)] may produce thrombogenic effects by modulating the fibrinolytic system. However, the role of Lp(a) level in the formation of left atrial thrombus has not been studied. We sought to evaluate whether Lp(a) is a risk factor for left atrial thrombus in patients with chronic atrial fibrillation.

METHODS AND RESULTS

The consecutive series of 150 patients (mean age 67 +/- 8 years) with chronic atrial fibrillation underwent transesophageal echocardiography. Left atrial thrombus was diagnosed by transesophageal echocardiography. Clinical, biochemical, and echocardiographic variables were prospectively collected. Univariate analysis showed that patients with left atrial thrombus (n = 29, 19%) had higher frequency of spontaneous echo contrast (93% vs 55%, P <.0001) than patients without left atrial thrombus (n = 121). Patients with left atrial thrombus also had a significantly higher serum concentration of Lp(a) (34.5 +/- 24.1 vs 17.9 +/- 13.5 mg/dL, P <.0001), a larger left atrium (5.4 +/- 0.9 vs 4.8 +/- 0.7 cm, P <.001), and a lower left atrial appendage peak flow velocity (11.1 +/- 5.4 vs 23.5 +/- 14.6 cm/s, P <.0001). Multivariate regression analysis showed that the Lp(a) concentration (P <.0001) was a significant positive predictor and the left atrial appendage peak flow velocity (P =.0125) was a significant negative predictor of left atrial thrombus. Left atrial thrombus was present in 16 (48%) of 33 patients with Lp(a) level >/=30 mg/dL.

CONCLUSIONS

Elevated serum levels of Lp(a) are strongly associated with left atrial thrombus. These findings suggest that Lp(a) level may be a novel risk factor for left atrial thrombus in patients with chronic atrial fibrillation.

Comparison of arrhythmogenicity of atrial pacing at several right atrial pacing sites: evaluation of canine atrial electrograms during atrial pacing and arrhythmogenicity for atrial fibrillation

The changes in the duration of atrial electrograms and the appearance of AF during atrial pacing were compared among five atrial pacing sites in dogs to clarify the arrhythmogenicity of atrial pacing at different atrial pacing sites. In seven mongrel dogs (15-20 kg), the right atrial surface was exposed by right thoracotomy. Atrial electrograms were recorded via bipolar electrodes with an interelectrode distance of 1.2 mm at four right atrial sites: (1) the high right atrium (HRA), (2) the mid-right atrium (MRA), (3) the low right atrium (LRA), and (4) the center of the pectinate muscle (PM). The duration of the atrial electrograms at these four recording sites were measured during atrial pacing with fixed cycle lengths of 200, 150, and 120 ms delivered at five atrial sites: (1) the HRA, (2) the inferior vena cava (IVC), (3) the right atrial appendage (RAA), (4) Bachman's bundle (BB), and (5) the atrial septum (AS). In each dog, the atrial pacing with the 120-ms cycle length was performed five times at each pacing site to evaluate the inducibility of AF. When AF was induced, the atrial recording site which first showed a fragmented atrial electrogram was considered the initiation site of the AF. AF was induced during 9 of 35 episodes of atrial pacing at the HRA site, 11 of 35 at the IVC site, 5 of 35 at the RAA site, 3 of 35 at the BB site, and none at the AS site. The initiation site of AF was in the HRA site in 11 of 28 episodes of induced AF, in the MRA site in 9 of 28, and in the LRA site in 8 of 28. At each recording site, the shorter the paced cycle length, the longer the duration of the atrial electrogram regardless of the pacing site. During the atrial pacing with the 200-ms cycle length, the HRA pacing resulted in the shortest duration of the atrial electrogram at each recording site in comparison with the other pacing sites. However, during atrial pacing at the two shorter paced cycle lengths, the duration of the atrial electrogram was shorter during the pacing at the BB or AS sites in comparison with the other three pacing sites, i.e., the HRA, IVC, and RAA sites. These results were the same for all atrial recording sites, but the prolongation of the atrial electrogram was most prominent at the HRA and MRA recording sites, which are most likely initiation sites of the induced AF. In the canine atria, (1) the initiation sites of AF were likely to be the HRA, MRA, or LRA sites in comparison with the PM site; and (2) the atrial pacing at the BB or AS sites was considered less arrhythmogenic for AF than the pacing at the HRA, LRA, or RAA sites.

A comparison of electrophysiologic properties between responders and non-responders to DL-sotalol among patients with ventricular tachyarrhythmia. Importance of the lack of a reverse use-dependent effect on ventricular refractoriness to responders

This study was undertaken to determine whether dl-sotalol can prevent ventricular tachyarrhythmia inducibility that can be predicted from electrophysiologic parameters. The effects of dl-sotalol in 16 patients (ventricular tachycardia (VT) in 11 and fibrillation (VF) in 5) were determined in electrophysiologic studies before and after dl-sotalol (320 mg/day). In 9 of 16 patients (56%) after dl-sotalol, ventricular tachyarrhythmia could not be induced by the entire stimulation protocol (responders). There were significant differences in QT interval (462 +/- 52 vs. 415 +/- 34 msec; p < 0.05) and ventricular effective refractory period (VERP) at 600, 400 and 300 msec (302 +/- 28 vs. 262 +/- 20 msec; p < 0.001, 280 +/- 23 vs. 240 +/- 21 msec; p < 0.001, 256 +/- 24 vs. 222 +/- 12 msec; p < 0.005, respectively) between responders and non-responders. The percentile increases in VERP (% VERP) at 600, 400, and 300 msec in responders were 25%, 26%, and 27%, whereas those in non-responders was 9%, 7%, and 7%, respectively. Isoproterenol administered to responders did not fully reverse the dl-sotalol-induced prolongation of VERP (delta VERP) at 600, 400, and 300 msec, which remained significantly prolonged compared to the baseline (281 +/- 18 vs. 241 +/- 16 msec; p < 0.01, 258 +/- 20 vs. 223 +/- 21 msec; p < 0.01, 247 +/- 22 vs. 202 +/- 16 msec; p < 0.01, respectively). % VERP did not exhibit significant differences at 600 (16%), 400 (15%), and 300 (20%) msec, indicating the lack of a reverse use-dependency. The results suggest that delta VERP in responders did not show reverse use-dependency, and that the phenomenon may account for the efficacy of dl-sotalol.

Comparison of electrophysiologic effects of intravenous E-4031 and MS-551, novel class III antiarrhythmic agents, in patients with ventricular tachyarrhythmias

Electrophysiologic effects of intravenous E-4031 and MS-551, novel class III antiarrhythmic agents, were evaluated in 5 and 6 patient with ventricular tachyarrhythmia, respectively. Six patients had sustained ventricular tachycardia (VT) and 5 had ventricular fibrillation (VF). Electrophysiologic study was performed before and after administration of E-4031 and MS-551 [E-4031; loading infusion 9 micrograms/kg for 5 min + 0.15 microgram/kg/min, MS-551; loading infusion 0.3 mg/kg for 5 min + 0.01 mg/kg/min]. The QT intervals were significantly prolonged after administration of E-4031 and MS-551 from 409 +/- 37 to 455 +/- 49 msec (11%), and from 359 +/- 52 to 411 +/- 63 msec (14%), respectively. The QTc intervals were significantly prolonged from 457 +/- 17 to 494 +/- 24 msec (8%), and from 410 +/- 36 to 452 +/- 47 (10%), respectively. There were no significant differences in the QT and QTc intervals between these two agents. The right ventricular effective refractory period (VERP) with E-4031 was prolonged at 600 (from 244 +/- 27 to 270 +/- 31 msec, 11 +/- 2%), 400 (from 222 +/- 23 to 242 +/- 24 msec, 9 +/- 3%), and 300 msec (from 206 +/- 19 to 218 +/- 25 msec, 6 +/- 4%), and those with MS-551 were prolonged at 600 (from 240 +/- 23 to 268 +/- 23 msec, 12 +/- 2%), 400 (from 225 +/- 22 to 250 +/- 24 msec, 11 +/- 4%), and 300 msec (from 213 +/- 14 to 228 +/- 18 msec, 7 +/- 4%). Both E-4031 and MS-551 prolonged VERP in a "reverse" use-dependent manner without changing the conduction velocity. E-4031 prevented the induction of VT in one patient. MS-551 prevented the induction of VT and VF in one patient each. Further evaluation of these selective class III agents may be needed to determine if higher doses are required to achieve the pharmacological effects in patients with ventricular tachyarrhythmias.

Electrophysiologic effects of intravenous MS-551, a novel class III antiarrhythmic agent, on human atrium and ventricle

The effects of intravenous MS-551, a new class III antiarrhythmic drug, on atrium and ventricle were evaluated in 6 patients with ventricular tachyarrhythmias (4 males and 2 females; mean age 45 +/- 21 years) in an electrophysiologic study. Two patients had sustained ventricular tachycardia (VT) and 4 patients had ventricular fibrillation (VF). Electrophysiologic study was performed before and after the administration of MS-551 (loading infusion 0.3 mg/kg for 5 min + 0.01 mg/kg/min). The QT and QTc intervals were significantly prolonged by MS-551 from 359 +/- 52 to 411 +/- 63 msec (p = 0.01) and from 410 +/- 36 to 452 +/- 47 (p = 0.0172), respectively. No effect was observed on the sinus cycle length, QRS duration, or AH and HV intervals in sinus rhythm. The effective refractory periods of the right atrium (AERP) were significantly prolonged at paced cycle lengths of 600 (from 222 +/- 19 to 250 +/- 23 msec, p = 0.0009), 400 (from 207 +/- 15 to 228 +/- 15, p < 0.0001) and 300 (from 193 +/- 10 to 205 +/- 8 msec, p = 0.0127) msec. Similarly, the right ventricular ERP (VERP) were significantly prolonged at paced cycle lengths of 600 (from 240 +/- 23 to 268 +/- 23 msec, p < 0.0001), 400 (from 225 +/- 22 to 250 +/- 24 msec, p = 0.0007), and 300 msec (from 213 +/- 14 to 228 +/- 18 msec, p = 0.0071). MS-551 prolonged AERP and VERP in a "reverse" use-dependent manner without changing the conduction time in patients with ventricular tachyarrhythmias. MS-551 prevented the induction of VT in 1 patient and VF in only 1 patient in this electrophysiologic study. Further evaluation of the therapeutic potential of MS-551 using higher dosages is necessary.

Effects of the ATP-sensitive K channel opener nicorandil on the QT interval and the effective refractory period in patients with congenital long QT syndrome. Investigator Group for K-Channel Openers and Arrhythmias

Congenital or idiopathic long QT syndrome is characterized by a frequently lethal ventricular arrhythmia called torsades de pointes (TdP) as well as a prolonged QT interval. The long QT interval related to an abnormal gene of the Na+ channel has been shown to be shortened by mexiletine. However, the action of K+ channel openers on the QT interval associated with abnormal genes of the K channel has yet to be studied. Seven patients of five families with long QT syndrome were included in this study, of whom six had syncope and six had documented TdP. Either long QT interval or sudden cardiac death had been observed in family members of all seven patients. At 1 to 3 weeks after admission, when TdP or frequent ventricular arrhythmia had subsided, nicorandil, an ATP-sensitive K channel opener, was administered orally at a dose of 15 mg/day in five patients and at 30 mg/day in the remaining two patients, and the effects were assessed on the third day after drug administration. In four patients, the effective refractory period was measured in the right ventricle before and after administration of K channel opener administration. The QT interval (QTc) prior to administration of the K channel opener was 0.60 +/- 0.09 ms (mean +/- SD) (0.61 +/- 0.10 second(1/2)), which was shortened to 0.54 +/- 0.05 ms (0.55 +/- 0.06 second(1/2)) on the third day of drug administration (P < .05 for both): 10.4 +/- 8.0% (8.6 +/- 5.5%). The QT interval at varying preceding R-R intervals on Holter electrocardiograms showed a shift toward the right as a result of the drug administration. The effective refractory period showed a significant prolongation, 256 +/- 26 ms versus 280 +/- 22 ms before and after drug administration, respectively (P <.05). Intravenous administration of nicorandil resulted in no significant change in heart rate or blood pressure, while QTc showed a tendency to shorten, but nonsignificantly (P = .08). However, a hump on the monophasic action potential was abolished, especially at the long preceding R-R interval induced by premature stimulation of the ventricle. It is concluded that nicorandil shortens the QT interval slightly when administered orally, whereas the effective refractory period shows a slight prolongation. The physiologic and clinical significance of these effects needs to be studied further.

Reentrant ventricular tachycardia. Interpretations of electrophysiologic findings and its applications

Monomorphic sustained ventricular tachycardia (MSVT) was revisited in relation to the electrophysiologic findings and their relation to the drug efficacy. Old myocardial infarction is less common cause of MSVT in Japan, and the majority (about 2/3) of MSVT is unrelated to coronary artery disease but, the mechanism shared a common mechanism: reentry with an excitable gap as others. The reentrant mechanism was supported from the inducibility, the terminability of VT by electrical stimulation, and by the ability to entrain with rapid pacing. In MSVT associated with underlying heart diseases, diseased myocardium showed low amplitude and fragmented electrograms and the area was considered to participate as the central common pathway of reentrant circuit. The area of slow pathway showed a decremental conduction or all-or-nothing conductive property. The width of the excitable gap seemed to be determined by the maximal conductive frequency but not by the duration of action potential: effective refractory period. As to the drug efficacy, there was no baseline characteristics in predicting the efficacy. However, the significant narrowing of the width of the excitable gap was associated with the drug efficacy and VT became non-inducible after addition of the same drug. The response pattern of the excitable gap to specific drug including class III, was not predictable. Further electropharmacological studies will be warranted.

Methotrexate maintains bone mass by preventing both a decrease in bone formation and an increase in bone resorption in adjuvant-induced arthritic rats

We examined the effects of low doses methotrexate (MTX) and indomethacin (IND) on bone mass and turnover in normal male Sprague-Dawley rats and those with adjuvant-induced arthritis. Normal and the adjuvant (heat-killed mycobacterium)-injected rats, 6 weeks of age, were given MTX at daily doses of 0.05, 0.1, or 0.2 mg/kg body weight (BW) or IND at a daily dose of 1.0 mg/kg BW. Rats were killed at the start, or at 14 and 28 days. In normal rats, the administration of these agents did not change the lumbar and femoral BMD values, nor did the serum osteocalcin or urinary deoxypyridinoline (D-Pyr) levels. Lumbar trabecular osteoclast number (Oc.N/BS) and osteoclast surface (Oc.S/BS) were decreased in the rats given IND. In the arthritic rats, the administration of MTX did not prevent an early increase of paw edema in the adjuvant-injected limb, but late inflammatory edema was alleviated in the non-injected limb. However, MTX administration at a dose of 0.1-0.2 mg/kg BW maintained an age-dependent increase in the lumbar and femoral BMD values. While serum osteocalcin levels were decreased and urinary D-Pyr values were increased in the arthritic control rats, these bone markers remained at the levels of the normal rats. Decreases in mineral apposition rate (MAR) and bone formation rate (BFR/BS) and increases in the trabecular Oc.N/BS and Oc.S/BS values were prevented by MTX. While IND almost completely prevented inflammatory paw edema, it did not improve the parameters of bone formation. An increase in osteoclasts was prevented and the osteopenia in the lumbar and the femoral bone was only partially prevented by IND. These data suggest that MTX improves bone mass and turnover in the arthritic rat, in which several cytokines that affect bone cells are involved. An increase in bone resorption may be due to prostaglandins, but bone formation defect was suggested to be due to other cytokines such as IL-1, IL-6, and TNF-alpha in this model.

Local bone turnover in the metaphysis of the proximal tibia and the lumbar vertebra during the early periods after ovariectomy in rats

To clarify the local changes in bone formation and resorption during the early period after ovariectomy (OVX), 200 SD rats, 4 months of age, underwent OVX or sham surgeries and seven to nine rats from each group were terminated at 1, 3, 7, 11, 15, 19, 23, 28, 35, 63, and 91 days postsurgery after tetracycline labeling. Serum intact osteocalcin levels were measured. Undecalcified sections of the 5th lumbar body (L5) and the right proximal tibia were measured for trabecular bone area, the labeled perimeters and the interlabeling distances after Villanueva's staining. On the 4th lumbar body (L4) and the left proximal tibia, undecalcified sections were measured for the trabecular osteoclast by tartrate-resistant acid phosphatase staining. The uterine horns were atrophied on the 3rd postovariectomy day (day 3). Serum osteocalcin levels increased on day 7 and reached the highest value on day 23. In either L5 or the metaphysis of the proximal tibia, trabecular bone volume (BV/TV) significantly decreased on day 15. The trabecular bone loss on day 28 was approximately 50% in the tibia and 15% in the L5. In either the lumbar or the tibia, osteoclast numbers significantly increased at day 3, and peaked between days 15 and 23. In the tibia, however, the bone formation rates (BFR/BS) were significantly reduced on the 3rd and 7th post-surgical days compared with the start value for both the OVX and sham groups. The BFR/BS values in L5 did not decrease during the first 7 days in either group. The BFR/BS values were then increased for both L5 and the tibia after day 7. These data clearly demonstrated that the local bone turnover 7 days post-OVX was identical in the proximal tibia and the lumbar vertebra. In the proximal tibia, however, it may be suggested that the increased bone resorption and reduced formation within 7 days after OVX due to the combined effects of both an estrogen deficiency and the surgical intervention would possibly play a critical role in the greater magnitude of the trabecular bone loss.

[Diagnostic value of glass microfibre-based basophil histamine release test in food allergic children. Comparison with specific IgE antibody and skin scratch test]

We evaluated the diagnostic value of the glass microfibre-based histamine release test (HRT), which allows measurements to be performed using small amounts of whole blood, in 50 children with food allergy case histories. The patients were evaluated by radioallergosorbent tests (RAST), skin scratch tests (ST) and food challenge tests. Of the 50 patients, 39 had a confirmed clinical diagnosis of food allergy from food challenge tests and case histories, and were affected by a total of 60 positive allergens (egg 37, milk 11, soy beans 4, wheat 5, rice 3). The concordance, sensitivity, and specificity of HRT with the clinical diagnosis were 85.3%, 66.7% and 92.1%, those of RAST were 59.4%, 90.0% and 48.2%, and those of ST were 84.7%, 71.8% and 88.7%, respectively. The positive predictive values of HRT, RAST and ST were 75.5%, 38.8% and 66.7%. The false positive ratio of HRT (24.5%) was the lowest among all the tests. There was a significant correlation between HRT and RAST (r = 0.513, p < 0.001). However, the concordance of HRT with respect to RAST was 56.0%. The concordance and specificity of HRT in relation to the clinical diagnosis were higher than RAST and the same as ST. The sensitivity of RAST was higher than that of HRT. From these results, we concluded that RAST is good for the screening of allergens and that HRT is a useful diagnostic method for the confirmation of a clinical allergy.

The effect of 17 beta-estradiol treatment on the mass and the turnover of bone in ovariectomized rats taking a mild dose of thyroxin

We performed the dosing experiment to establish whether estrogen administration has any beneficial effects on the mass and the turnover of bone in ovariectomized rats taking a mild dose of thyroxin. Thirty-five Wistar rats, 28 weeks of age, received ovariectomies (OVX) or sham operations and were divided into five groups. Group 1 was the sham group, Groups 2-5 were ovariectomized. Group 2 was the OVX-control, Group 3 treated with thyroxin 30 micrograms/kg/day (T4), Group 4, 17 beta-estradiol 0.3 mg/kg/week (E2), and Group 5, the combination of T4 and E2. The duration of the experiment was 12 weeks. At the end of the experiment, serum chemistries were measured. Bone minerals in the femur were determined with single photon absorptiometry and bone turnover was assessed histomorphometrically. Alkaline-phosphatase increased in Group 3 (OVX-T4), but it reduced in Groups 4 (OVX-E2) and 5 (OVX-T4 + E2). Bone minerals decreased in Groups 2 (OVX) and 3. In Group 4, it was preserved at the same level as in Group 1. Group 5 showed a significant increase of bone mass compared with Group 1. Eroded surface and osteoid surface increased in Groups 2 and 3 and they were reduced in Groups 4 and 5. Bone volume and mineral apposition rate were at a maximum in Group 5. This study demonstrated that 17 beta-estradiol was capable of preventing the bone mass decrease by regulating the turnover in ovariectomized rats taking a mild dose of thyroxin. Osteoblast function appeared to be stimulated in combination with 17 beta-estradiol and thyroxin.

[Assessment of the amount of drug deposited in the lungs of asthmatic children using disodium cromoglycate as the marker]

Disodium cromoglycate (DSCG) is easily absorbed from the airways and lungs, and is excreted unchanged in the urine and bile. Therefore it is possible to estimate the dose of DSCG deposited in the airways and lungs based upon urinary excretion. The urinary concentration of DSCG was measured by the HPLC method in 78 asthmatic children aged 0 to 16 years after they had inhaled 20 mg nebulizer solutions with facemasks. Jet-type nebulizers were used. The mean urinary excretion of DSCG in the patients aged 0, 1, 2 and 3 years from 4-hour urinary collection represented 0.204%, 0.231%, 0.593%, 0.790%, respectively, of the dose administered. In the patients aged 3, 4, 5-6, 7-9 and 10-16 years, from 24-hour urinary collection, the figures were 0.625%, 0.895, 0.855, 1.176%, 1.070%, respectively. The mean dose deposited in the airways and lungs of the age groups 0-1, 2, 3, 4-6, 7-9, and 10-16 years represented approximately 0.5%, 1.4%, 1.4-1.8%, 2.0%, 2.7%, 2.4%, respectively, of the dose administered. Although there was a wide range in the total amount of DSCG deposited in the airways and lungs of asthmatic children, these data seem to provide a useful guide to standardizing the dosing in inhalation therapy.

Reduced mechanical competence of bone by ovariectomy and its preservation with 24R,25-dihydroxyvitamin D3 administration in beagles

To examine changes in mechanical competence of bone caused by ovariectomy, and to assess the effect of 24R,25-dihydroxyvitamin D3 (24R,25(OH)2D3) administration on mass and structure, we conducted mechanical tests on canine lumbar vertebrae and femur 31 months after surgery. Beagles weighing 9-10 kg were ovariectomized (OVX) or sham operated (n = 3, group 1). OVX dogs were divided into three groups. Group 2 (n = 3) received only the agent vehicle, groups 3 (n = 4) and 4 (n = 4) received daily 24R,25(OH)2D3 doses of 2 and 10 mcg/kg, respectively from 1 month after surgery. In group 4, the dose level was increased up to 100 mcg/kg by the 17 month. Then, L3 and L4 vertebrae and left femur were excised from each animal. Torsional tests at the femoral diaphysis were conducted. On the L3 specimen, the circumferential shell was removed to obtain a cancellous core specimen. The shell was left intact on the L4 specimen. In compression tests, the loading was stopped just after maximal strength was reached for minimum specimen collapse, from which 7-mcm thick, undecalcified, midcross sections parallel to the base of the specimen were obtained. Neither femoral morphology, bone mineral contents (BMCs) nor structural stiffness indicated a significant difference among groups. Though L3 and L4 BMCs were reduced in group 2, in group 3 and 4 they were significantly larger than in group 2. Compression tests on lumbar vertebral specimens showed a significant decrease in mechanical parameters in group 2. On the cancellous core specimen of L3, the mean structural stiffness in group 2 was 31.8% of that in group 1.(ABSTRACT TRUNCATED AT 250 WORDS)

The displacement of the femoral head by rotational acetabular osteotomy. A radiographic study of 97 subluxated hips

To determine the limits of medial and inferior displacement of the subluxated femoral head by rotational acetabular osteotomy, we studied the acetabular coverage and position of the femoral head radiographically before and after surgery in 97 hips. The median age of the patients at the time of surgery was 33 (18-54) years. The position of the femoral head was represented by its center and medial and upper borders. The average increase and decrease in the CE and the AC angle were 39 degrees and 27 degrees, respectively. The average medial displacement of the head was 8 (-12 to +19) mm measured from its center, and 7 (-10 to +21) mm measured from its medial border. The average inferior displacement was 5 (-6 to +19) mm from its center and 4 (-10 to +15) mm from the upper border. These results indicate that concentric reduction by rotational acetabular osteotomy is limited and that medial displacement of the subluxated femoral head is within similar ranges obtained by other conventional pelvic osteotomies.

Molecular cloning and nucleotide sequence of the cDNA for human liver glutamate dehydrogenase precursor

Two cDNA clones (lambda GDHh1 and lambda GDHn61) for glutamate dehydrogenase (GDH) were isolated from a human liver cDNA library in lambda gt11. The clone, lambda GDHh1, was isolated from the library using a synthetic 45mer oligodeoxy-ribonucleotide, the sequence of which was derived from the known amino acid sequence near the NH2-terminus of human liver GDH. Subsequently, lambda GDHn61 was isolated from the same library using lambda GDHh1 as a probe. The inserts of both clones contained an overlapping cDNA sequence for human liver GDH, consisting of a 5'-untranslated region of 70 bp, an open reading frame of 1677 bp, a 3'-untranslated region of 1262 bp and a 15 base poly(A) tract. The predicted amino acid sequence revealed that the human liver GDH precursor consisted of a total of 558 amino acid residues including the NH2-terminal presequence of 53 amino acids. The sequence deduced for the mature enzyme showed 94% homology to the previously reported amino acid sequence of human liver GDH.