Hyperuricemia predicts worse prognosis in patients with chronic coronary syndrome after percutaneous coronary intervention: insights from Japanese real-world database using a storage system

Background

The relationship between hyperuricemia (HUA) and cardiovascular disease was observed in some epidemiological studies. However, the association between HUA and chronic coronary syndrome (CCS) after percutaneous coronary intervention (PCI) is not fully elucidated.

Purpose

The purpose of this study was to investigate the prognostic impact of HUA in patients with CCS after PCI.

Methods

This study is a retrospective, multicenter, observational study. We developed the Clinical Deep Data Accumulation System (CLIDAS), which consists of 6 university hospitals and the national cardiovascular center in Japan, directly obtains clinical data including patients background, laboratory data, echocardiogram, electrocardiogram, cardiac catheterization report, prescription, and long-term outcome from electronic medical records. A total of 9936 consecutive patients after PCI were analyzed. Of them, 5138 patients with CCS after PCI during April 2013 and March 2019 were analyzed, and divided into HUA group (patients with HUA at baseline, n=1724) and non-HUA group (patients without HUA at baseline, n=3414). HUA was defined as a serum uric acid levels ≥7.0 mg/dL for men or ≥6.0 mg/dL for women and/or taking urate-lowering drugs. The primary outcome was the major cardiovascular events (MACE) defined as being the composite of cardiovascular death, myocardial infarction, and hospitalization for heart failure.

Results

The median follow-up duration was 910 days (interquartile range: 307–1479 days). The proportion of male (78% vs. 78%) and age (71±11 vs. 71±10) were similar between the HUA and the non-HUA groups. The prevalence of hypertension (87% vs. 82%), atrial fibrillation (9% vs. 5%), and history of previous hospitalization for heart failure (15% vs. 6%) and baseline creatinine value (1.8±2.3 vs. 1.5±2.0 mg/dL) were significantly higher in the HUA group. In contrast, the prevalence of diabetes (43% vs. 48%) was significantly lower in the HUA group. The incidence of MACE was significantly higher in the HUA group than in the non-HUA group (13.1% vs. 6.4%, log rank P<0.001). Multivariate Cox regression analyses revealed that hyperuricemia was significantly associated with MACE (hazard ratio 1.50, 95% confidence interval 1.22–1.84, P<0.001) after controlling for other cardiovascular risk factors.

Conclusion

The real-world database CLIDAS revealed that hyperuricemia was significantly associated with the increase of MACE in patients with CCS after PCI. This result sheds light on the significant role of urate in prediction of prognosis, suggesting the possibility of new therapeutic approaches using urate-lowering drugs or SGLT2 inhibitors for the CCS patients.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Jichi Medical University, Tochigi, Japan, and Kowa Co., Ltd

Isolation of Human Coronaviruses OC43, HKU1, NL63, and 229E in Yamagata, Japan, Using Primary Human Airway Epithelium Cells Cultured by Employing an Air-Liquid Interface Culture

Isolation of seasonal coronaviruses, which include human coronavirus (HCoV) OC43, HCoV-HKU1, and HCoV-NL63, from primary cultures is difficult because it requires experienced handling, an exception being HCoV-229E, which can be isolated using cell lines such as RD-18S and HeLa-ACE2-TMPRSS2. We aimed to isolate seasonal CoVs in Yamagata, Japan to obtain infective virions useful for further research and to accelerate fundamental studies on HCoVs and SARS-CoV-2. Using modified air-liquid interface (ALI) culture of the normal human airway epithelium from earlier studies, we isolated 29 HCoVs (80.6%: 16, 6, 6, and 1 isolates of HCoV-OC43, HCoV-HKU1, HCoV-NL63, and HCoV-229E, respectively) from 36 cryopreserved nasopharyngeal specimens. In ALI cultures of HCoV-OC43 and HCoV-NL63, the harvested medium contained more than 1 × 10⁴ genome copies/µL at every tested time point during the more than 100 days of culture. Four isolates of HCoV-NL63 were further subcultured and successfully propagated in an LLC-MK2 cell line. Our results suggest that ALI culture is useful for isolating seasonal CoVs and sustainably obtaining HCoV-OC43 and HCoV-NL63 virions. Furthermore, the LLC-MK2 cell line in combination with ALI cultures can be used for the large-scale culturing of HCoV-NL63. Further investigations are necessary to develop methods for culturing difficult-to-culture seasonal CoVs in cell lines.

Longitudinal epidemiology of human coronavirus OC43 in Yamagata, Japan, 2010-2017: Two groups based on spike gene appear one after another

Human coronavirus OC43 (HCoV-OC43) is divided into genotypes A to H based on genetic recombination including the spike (S) gene. To investigate the longitudinal transition of the phylogenetic feature of the HCoV-OC43 S gene in a community, phylogenetic analysis of the S1 region of the S gene was conducted using 208 strains detected in Yamagata during 2010 to 2017 with reference strains of the genotype. The S1 sequences were divisible into four groups: A to D. All Yamagata strains belonged to either group B or group D. In group B, 46 (90.2%) out of 51 Yamagata strains were clustered with those of genotype E reference strains (cluster E). In group D, 28 (17.8%) and 122 (77.7%) out of 157 Yamagata strains were clustered, respectively, with genotype F and genotype G reference strains. In cluster G, 28 strains formed a distinct cluster. Monthly distributions of HCoV-OC43 in Yamagata in 2010 to 2017 revealed that group B and group D appeared one after another. In group B, the cluster E strains were prevalent recurrently. In conclusion, epidemics of HCoV-OC43 in Yamagata, Japan might be attributable to two genetically different groups: group B showed a recurrent epidemic of strains belonging to a single phylogenetic cluster and group D showed epidemic strains belonging to multiple clusters.

Genotypic diversity of Streptococcus suis and the S. suis-like bacterium Streptococcus ruminantium in ruminants

Although Streptococcus suis has attracted public attention as a major swine and human pathogen, this bacterium has also been isolated from other animals, including ruminants. However, recent taxonomic studies revealed the existence of other species that were previously identified as S. suis, and some of these isolates were reclassified as the novel species Streptococcus ruminantium. In Japan, biochemically identified S. suis is frequently isolated from diseased ruminants; however, such isolates have not yet been identified accurately, and their aetiological importance in ruminants is unclear. Therefore, to understand the importance of S. suis and S. suis-like bacteria in ruminants, we reclassified S. suis isolates from ruminants according to the updated classification and investigated their genetic diversity. Although both S. suis and S. ruminantium were isolated from healthy and diseased ruminants, most of the isolates from diseased animals were S. ruminantium, implying that S. ruminantium is more likely to be associated with ruminant disease than S. suis. However, the ruminant S. suis and S. ruminantium isolates from diseased animals were classified into diverse genotypes rather than belonging to certain clonal groups. Genome sequence analysis of 20 S. ruminantium isolates provided information about the antibiotic resistance, potential virulence, and serological diversity of this species. We further developed an S. ruminantium-specific PCR assay to aid in the identification of this bacterium. The information obtained and the method established in this study will contribute to the accurate diagnosis of ruminant streptococcal infections.

Clinical characteristics of children infected with enterovirus D68 in an outpatient clinic and the association with bronchial asthma

BACKGROUND

All reports of increases in severe respiratory disease associated with human enterovirus D68 (EV-D68) are from hospital settings. However, there are few reports describing clinical characteristics in less severely affected populations.

METHODS

We conducted a retrospective observational study from January 2010 to December 2015 in Yamagata, Japan. Using regional passive surveillance, 5794 respiratory specimens were collected from children who initially presented to an outpatient clinic with acute respiratory symptoms. The collected samples were tested for EV-D68 by reverse transcription PCR.

RESULTS

EV-D68 was detected in 79 specimens mainly during the two epidemic periods in August-October 2010 and August-October 2015, when detection rates were 10.2% (31 of 304 specimens) and 16.3% (46 of 282 specimens), respectively. Among the 69 EV-D68-positive children, excluding those with viral coinfection, 39 (57%) had upper respiratory tract infections, 23 (33%) bronchiolitis or asthma attack, 5 (7%) bronchitis, 1 (1%) meningitis and 1 (1%) acute flaccid paralysis. In 23 children with wheezing, retraction was observed in 10 (43%), and six (26%) were diagnosed with asthma exacerbation. Six children required hospital admission, five (83%) because of asthma exacerbation. A history of asthma or wheezing was the most significant risk factor for the development of wheezing (odds ratio, 8.23; 95% CI, 2.65-25.50; p < .001).

CONCLUSIONS

The low rate of hospitalization (9%, 6 of 69) indicates that most cases with EV-D68 infection were managed as outpatients. A history of asthma or wheezing was a potential risk factor for wheezing, resulting in hospitalization due to a severe asthma attack.

Detection of Saffold viruses from children with acute respiratory infections in Yamagata, Japan, between 2008 and 2015

Although Saffold virus (SAFV) was reported as a novel human cardiovirus in 2007, no causative association between SAFV and clinical disease has been proven and the longitudinal epidemiology of SAFVs is not available. To establish the relationship between SAFVs and acute respiratory infections (ARIs) and to clarify the longitudinal epidemiology of SAFVs, 7258 nasopharyngeal specimens were collected from children with ARIs in Yamagata, Japan between 2008 and 2015. The specimens were inoculated on a microplate including six cell lines as part of routine surveillance, and molecular screening was performed for SAFVs using a reverse transcription (RT)-PCR method. Throughout the study period, 95 (1.3%) SAFV genotype 2 (SAFV2), and 28 (0.4%) SAFV3 were detected, mainly between September and November. There were two outbreaks of SAFV2 in 2009 and 2013, and one outbreak of SAFV3 in 2012 and the positive rates during these outbreaks were 12.1% (53/439), 11% (35/319), and 4.4% (20/453), respectively. Sixty-three SAFV2 and 28 SAFV3 strains were detected as a single virus from children with ARIs such as pharyngitis, herpangina, and tonsillitis. These results suggested that SAFV2 and SAFV3 are possible causative agents of ARIs among children and their infections occur mainly in the autumn season in Japan.

Seroepidemiology of human parechovirus types 1, 3, and 6 in Yamagata, Japan, in 2014

To clarify the seroepidemiology of human parechovirus type 1 (HPeV1), 3 and 6, neutralizing antibodies (NT Abs) were measured in 214 serum specimens collected in 2014 in Yamagata, Japan. The seroprevalence against HPeV1 was 100% in all age groups, while that against HPeV3 and HPeV6 was 79.4% and 66.8%, respectively, overall. The geometric mean titers of NT Abs against HPeV1, 3 and 6 were 755.2, 255.0 and 55.9, respectively, overall. Our findings indicate that HPeV1 is the most prevalent HPeV circulating in Yamagata, followed by HPeV3 and HPeV6.

Chronological changes of mumps virus genotypes in Japan between 1999-2013

BACKGROUND

The molecular epidemiology of mumps virus (MuV) has been carried out worldwide based on genotyping proposed by the World Health Organisation. However, longitudinal molecular epidemiological studies of MuV are still limited.

METHODS

This study carried out genotyping of MuVs isolated in Yamagata prefecture, which is located in northern Japan, between 1999-2013, using standard nomenclature based on the sequence analysis of the entire 316 nucleotides of the small hydrophobic (SH) gene.

RESULTS

During this 15-year period, 249 MuVs were isolated, with the majority of them belonging to genotype G. Phylogenetic analysis revealed that genotype G strains were divided into two distinct clusters 1 and 2, consisting of 178 and 47 strains, respectively. The cluster 1 strains were isolated every year since 2001, except for 2012. The cluster 2 strains first appeared in 2011 and were dominant in 2011 and 2012. The epidemic pattern of genotype G strains observed in Yamagata was similar to those in Kanagawa and Hyogo prefectures located in eastern and western Japan, respectively. Only one L, three H and one F genotype strains were isolated in 2001, 2004 and 2010, respectively. Almost every year several genotype B strains related to Japanese vaccine strains were isolated.

CONCLUSIONS

These data demonstrated that the genotype G strains have been endemically perpetuating as the major type over a wide area of Japan since 2001, although the genotype G strains that emerged after 2011 differed from the earlier strains.

Detection of the human coronavirus 229E, HKU1, NL63, and OC43 between 2010 and 2013 in Yamagata, Japan

The available literature on human coronaviruses (HCoVs) in Japan is limited to epidemiological studies conducted over a maximum of 1 year. We conducted a 4-year study of HCoVs by analyzing 4,342 respiratory specimens obtained in Yamagata, Japan, between January 2010 and December 2013. A pan-coronavirus reverse transcription-PCR screening assay was performed, and all HCoV-positive specimens were subsequently confirmed by sequencing of the PCR products. We detected in 332 (7.6%) HCoV strains during the study period, comprising 133 (3.1%) HCoV-NL63, 83 (1.9%) HCoV-HKU1, 78 (1.8%) HCoV-OC43, and 38 (0.9%) HCoV-229E strains. HCoV detection per year ranged from 3.5% to 9.7%. HCoVs were detected mainly in winter, with January (28.5%) and February (25.3%) 2011 and December 2012 (14.6%) being the only months in which HCoV-NL63 detection per month exceeded 10.0%. HCoV-HKU1 displayed clear biennial peaks in January (18.3%) and February (10.7%) 2010 and in February (18.8%) and March (14.7%) 2012. The peak detection of HCoV-OC43 was 13.6% in November 2010, while that of HCoV-229E was 10.8% in March 2013. Our results indicated that there may be annual variations in the circulation of individual HCoV strains. Further long-term surveillance is necessary to clarify HCoV prevalence and circulation patterns in Japan.

Molecular epidemiology of enterovirus 71 strains isolated from children in Yamagata, Japan, between 1990 and 2013

Enterovirus 71 infections have become a major public issue in the Asia-Pacific region due to the large number of fatal cases. To clarify the longitudinal molecular epidemiology of enterovirus 71 (EV71) in a community, we isolated 240 strains from children, mainly with hand-foot-and-mouth diseases, between 1990 and 2013 in Yamagata, Japan. We carried out a sequence analysis of the VP1 region (891 bp) using 223 isolates and identified six subgenogroups (B2, B4, B5, C1, C2 and C4) during the study period. Subgenogroups C1 and B2 were found only between 1990 and 1993 and have not reappeared since. In contrast, strains in subgenogroups C2, C4 and B5 appeared repeatedly with genomic variations. Recent reports from several local communities in Japan have suggested that identical predominant subgenogroup strains, which have also been found in the Asia-Pacific region, have been circulating in a wide area in Japan. However, it is likely that there is a discrepancy between the major subgenogroups circulating in the Asia-Pacific region and those in Europe. It is necessary to continue the analysis of the longitudinal epidemiology of EV71 in local communities, as well as on regional and global levels, to develop strategies against severe EV71 infections.

Molecular evidence for the presence of new Babesia species in feral raccoons (Procyon lotor) in Hokkaido, Japan

We recently reported that feral raccoons (Procyon lotor) with splenomegaly native to Japan were carriers of a Babesia microti-like parasite identical to that found in the United States, which was likely introduced to Japan from North America via raccoons imported as pets. Thus, we attempted extensive molecular survey for piroplasma infections of feral raccoon with normal spleen in Hokkaido, Japan using nested PCR that target broadly to 18S ribosomal RNA gene (SSU-rDNA) of all the parasites in the genus Babesia, Theileria, Cytauxzoon and B. microti group. Of the 348 raccoon samples analyzed, 9 gave positive signals. Cloning and phylogenetic analysis on SSU-rDNA sequences revealed that six of nine positives were found to be infected with Babesia and the remaining three with previously unreported Sarcocystis. Babesia sequences were further separated into two distantly related groups, those that reside in a novel phylogenetic group were consisted solely of four parasites found in this study, while those which included one identical sequence found in the three of our specimens were assembled together with both Babesia parasites of tick's in Japan and of raccoon's in U.S. These results may indicate that not only a B. microti-like parasite but also at least two yet undescribed Babesia species are being established in their new life cycles in the feral raccoon populations in Japan.

Epidemiology, histopathology, and muscle distribution of Trichinella T9 in feral raccoons (Procyon lotor) and wildlife of Japan

The prevalences of Trichinella T9 in trapped raccoons (Procyon lotor) and several other potential mammalian reservoirs in Hokkaido, Wakayama, and Nagasaki Prefectures were investigated. Muscle samples were collected from 2003 to 2006 from 1,080 raccoons, 113 raccoon dogs including 2 species (Nyctereutes procyonoides albus and N. p. viverrinus), 41 wild boars (Sus scrofa leucomystax), 14 martens (Martes melampus), 10 badgers (Meles meles), 5 Siberian weasels (Martes sibirica coreana), 7 mink (Mustela vison), and 1 red fox (Vulpes vulpes japonica). The samples were digested, and the prevalence and mean intensity of infection with the Trichinella muscle larvae were determined. The prevalence and intensity of the muscle larvae were 0.9% and 93.3 larvae/g (range 0.4-201.8) in raccoons, and 1.6% and 61.6 larvae/g in raccoon dogs, respectively. The infected animals were captured in different areas in Hokkaido Prefecture. These results confirmed that raccoons, which have been introduced from North America since the 1970s, are involved in the sylvatic cycle of Trichinella in Japan. In raccoons, the muscle density of Trichinella T9 larvae was highest in the tongue, and larvae were not found in the heart muscle or diaphragm. This is the first report of Trichinella T9 infection of feral raccoons in Japan.

Babesia microti-like parasites detected in feral raccoons (Procyon lotor) captured in Hokkaido, Japan

Raccoons (Procyon lotor), which have recently become feral in Japan, were examined for the presence of Babesia microti-like parasites. Out of 372 raccoons captured in the west-central part of Hokkaido, 24 animals with splenomegaly were selected and tested by nested PCR targeting the babesial 18S rRNA gene. B. microti-like parasites were detected in two of the 24 individuals, and their DNA sequences were identical to that of the B. microti-like parasite reported from raccoons in the United States, suggesting that the parasites were probably imported into Japan and that the life cycle of the parasite has already been established in the country. The potential risk of this B. microti-like parasite spreading among dogs and foxes in Japan will need to be carefully monitored, as parasitization by phylogenetically very close parasites has been reported from such animals.

Reproductive characteristics of the feral raccoon (Procyon lotor) in Hokkaido, Japan

Reproduction of feral raccoons (Procyon lotor) in Hokkaido, Japan, was examined during a 2-year period by analysis of placental scars or fetuses in the uterus. Of 242 collected females, 69 (29%) were juveniles, 71 (29%) yearlings, and 102 (42%) adults. The pregnancy rate averaged 66% in yearlings and was significantly lower than the 96% average observed in adults (p<0.01). Litter size ranged from 1 to 7 offspring per female, and averaged 3.6 in yearlings and 3.9 in adults. There was no significant difference in mean litter size between yearlings and adults. In Hokkaido, the raccoon mating season peaked in February and the majority of litters were born between March and May, similar to patterns described in North America, but some females mated in summer. The reproductive potential of feral raccoons in Hokkaido was similar to that reported in North America. The recent increase in raccoon numbers can be explained by their high productivity. Harvest data suggest that hunting pressure on juveniles is lower than that for older age classes when using box traps in summer. In order to reduce the feral raccoon population, alternative hunting methods that increase juvenile mortality rates are needed.

Growth pattern and seasonal weight changes of the feral raccoon (Procyon lotor) in Hokkaido, Japan

The growth pattern and seasonal weight fluctuations of feral raccoons in Hokkaido were evaluated between 1999 and 2001. The growth rates inbody length and body weight were described for juveniles (young of the year) and yearlings (animals born in the previous season) using the Gompertz growth model. The asymptotic body sizes for males were greater than those for females. Young raccoons born during spring in the study area could potentially grow up to their asymptotic size at the beginning of their first winter, but they would not reach their full adult sizes until at least their second fall. Adult raccoons (animals > or = 2 -year-old) had seasonal weight fluctuations with annual weight loss of 25% to 28% of mean maximum weights in west-central Hokkaido, but these result would be an underestimate of the degree of annual weight fluctuations. Juvenile raccoons can be distinguished from the older animals by measuring body length or body weight during fall in Hokkaido.

Atrial fibrillation threshold predicted long-term efficacy of pharmacological treatment of patients without structural heart disease

AIMS

To ascertain if an electrophysiological study could predict long-term efficacy of anti-arrhythmic drugs in the treatment of lone atrial fibrillation.

METHODS AND RESULTS

Forty-four patients (36 males, 8 females, age 55.5 +/- 10.6) with paroxysmal atrial fibrillation were enrolled to undergo serial electrophysiological studies at the bedside. Two quadripolar catheters were inserted via the subclavian vein. Disopyramide (D: 2 mg/kg iv), cibenzoline (C: 1.4 mg/kg iv), aprindine (A: 2 mg/kg iv), pilsicainide (P: 2 mg/kg po) and flecainide (F: 3 mg/kg po) were tested. Atrial fibrillation threshold (AFT) was measured as the lowest current amplitude of rapid pacing (50 Hz for 1 s) to induce atrial fibrillation lasting more than 30 s. Before drug treatment, AFT was 3.9 +/- 0.3 mA. Pharmacological treatment raised AFT as follows: D 5.9 +/- 0.9 mA, C 7.6 +/- 1.2 mA, A 8.1 +/-1.1 mA, P 6.0 +/- 0.8 mA, F 7.3 +/- 1.1 mA. Recurrence of atrial fibrillation was observed during 1-year follow-up in 12% of cases when they were treated with a drug that raised AFT by 5 mA or more. On the other hand, the recurrence rate was 87% when patients were treated with a drug that raised AFT by less than 5 mA (P = 0.001).

CONCLUSION

AFT was a good predictor of long-term efficacy of pharmacological treatment against atrial fibrillation.

Successful thrombus removal using 6Fr hydrolyser thrombectomy catheter in acute myocardial infarction via radial artery

The 6Fr Hydrolyser thrombectomy catheter for acute myocardial infarction (AMI) successfully removed a massive thrombus in the coronary artery in three patients. The 6Fr Hydrolyser catheter could be advanced into the right coronary artery with bare-wire methods via a 6Fr sheath at the radial artery. This approach suggests that the device can be an alternative method for thrombolysis in selected AMI patients with massive thrombus in the coronary artery.

Clinical significance of the atrial fibrillation threshold in patients with paroxysmal atrial fibrillation

AF threshold and the other electrophysiological parameters were measured to quantify atrial vulnerability in patients with paroxysmal atrial fibrillation (PAF, n = 47), and those without AF (non-PAF, n = 25). Stimulations were delivered at the right atrial appendage with a basic cycle length of 500 ms. The PAF group had a significantly larger percentage of maximum atrial fragmentation (%MAF, non-PAF: mean +/- SD = 149 +/- 19%, PAF: 166 +/- 26%, P = 0.009), fragmented atrial activity zone (FAZ, non-PAF: median 0 ms, interquartile range 0-20 ms, PAF: 20 ms, 10-40 ms, P = 0.008). Atrial fibrillation threshold (AF threshold, non-PAF: median 11 mA, interquartile range 6-21 mA, PAF: 5 mA, 3-6 mA, P < 0.001) was smaller in the PAF group than in the non-PAF group. Sensitivity, specificity, and positive predictive value of electrophysiological parameters were as follows, respectively: %MAF (cut off at 150%, 78%, 52%, 76%), FAZ (cut off at 20 ms, 47%, 84%, 85%), AF threshold (cut off at 10 mA, 94%, 60%, 81%). There were no statistically significant differences between the non-PAF and PAF groups in the other parameters (effective refractory period, interatrial conduction time, maximum conduction delay, conduction delay zone, repetitive atrial firing zone, wavelength index), that were not specific for PAF. In conclusion, the AF threshold could be a useful indicator to evaluate atrial vulnerability in patients with AF.

[Pressure wire guide provisional coronary stent implantation]

OBJECTIVES

Whether coronary artery lesion successfully dilated by balloon angioplasty should be stented or not is unclear. The purpose of this study is to evaluate the provisional stent implantation method assessing residual ischemia by pressure wire.

METHODS

Thirty-one patients with de-novo lesions suitable for stenting were enrolled in a pressure wire guided provisional stent study. The pressure wire was used to assess the fractional flow reserve(FFR) before and after balloon angioplasty. When the FFR after angioplasty was less than 0.75, stent implantation was planned. Patients with lesions consisting of an intermediate stenosis proximal to the target lesion, chronic total occlusion, bypass graft and left main lesion were excluded from the study. Stent implantation was permitted even if the FFR was more than 0.75 when the operator thought stenting was necessary. Medical treatment was given with aspirin 162 mg/day, cilostazol 200 mg/day for 6 months and additional ticlopidine 200 mg/day for a month after stenting the lesion.

RESULTS

Target vessel was the left anterior descending coronary artery in 19 lesions, the right coronary artery in 3, and the circumflex coronary artery in 9. Stent implantation was performed in seven (23%) of 31 lesions and the other 24(77%) lesions were treated with only balloon angioplasty. The FFR before intervention was 0.58 +/- 0.16, and improved to 0.87 +/- 0.07 (p < 0.0001). Percentage diameter stenosis before intervention was 70.7 +/- 12.6% and improved to 20.1 +/- 13.3% (p < 0.0001) after intervention. There was no major cardiac event (death, coronary artery bypass grafting, myocardial infarction, stent thrombosis). Six months follow-up angiography was performed in 27 patients (87%). Angiographic restenosis (percentage diameter stenosis > or = 50%) was found in four patients (15%). A new lesion was found in two patients. Target vessel revascularization was performed in six patients (21%).

CONCLUSIONS

Lesions successfully dilated by balloon angioplasty with FFR > or = 0.75 do not require stenting.

Crystal structures of the transposon Tn5-carried bleomycin resistance determinant uncomplexed and complexed with bleomycin

The transposon Tn5 carries a gene designated ble that confers resistance to bleomycin (Bm). In this study, we determined the x-ray crystal structures of the ble gene product, designated BLMT, uncomplexed and complexed with Bm at 1.7 and 2.5 A resolution, respectively. The structure of BLMT is a dimer with two Bm-binding pockets composed of two large concavities and two long grooves. This crystal structure of BLMT complexed with Bm gives a precise mode for binding of the antibiotic to BLMT. The conformational change of BLMT generated by binding to Bm occurs at a beta-turn composed of the residues from Gln(97) to Thr(102). Crystallographic analysis of Bm bound to BLMT shows that two thiazolium rings of the bithiazole moiety are in the trans conformation. The axial ligand, which binds a metal ion, seems to be the primary amine in the beta-aminoalanine moiety. This report, which is the first with regard to the x-ray crystal structure of Bm, shows that the bithiazole moiety of Bm is far from the metal-binding domain. That is, Bm complexed with BLMT takes a more extended form than the drug complexed with DNA.

Crystallization and preliminary X-ray diffraction studies of Streptomyces phospholipase A2 in a calcium-binding form

Phospholipase A2 (PLA2) as a calcium-binding form, produced by Streptomyces violaceoruber, was crystallized in a form suitable for the diffraction analysis using the vapor diffusion method. Crystals were grown in 0.1 M Tris-HCl buffer (pH 8.5), 20 mM Ca2+ containing 50-60% (v/v) 2-methyl-2,4-pentanediol as a precipitant. They belong to the monoclinic space group P2(1), with the cell dimensions a=38.3 A, b=54.3 A, c=30.6 A, and beta=90.2 degrees. The crystals diffract the X-ray well and the diffraction intensity data were collected up to 1.6 A resolution. The crystal volume per unit mass, V(M) is 2.35 A3 Da(-1) with one molecule in the asymmetric unit, which corresponds to a solvent content of 47.7%.

Elastomeric Comb-Shaped High Molecular Mass Poly(Oxyethylene) for Polymer Electrolyte: Morphology and Ionic Conductivity

The morphology, dynamic mechanical properties and ionic conductivity of high molecular mass comb-shaped poly(oxyethylene)s with tri(oxyethylene) side chains (TECs) were investigated, when LiClO4 was doped at the concentration of [Li]/[ —O—] = 0.05 ∼ 0.15. The samples were TEC-11 and TEC-18, the contents of tri(oxyethylene) side chain of which were 11 and 18 mol%, respectively. With increasing salt concentration, the glass transition temperature increased and the melting temperature decreased followed by the disappearance of the melting point. By adding the salt at the concentration of [Li]/[—O—] = 0.10 or 0.15, an alternative structure was suggested to be formed although the poly(oxyethylene) matrix was completely amorphous. Due to the morphological characteristics of TECs and the concentration of the salt, both TEC-11 and TEC-18 exhibit the high ionic conductivities of 10−4 S/cm at 30°C, when the salt was doped at the concentration of [Li]/[—O—] = 0.10. The high molecular mass, over 106, of TECs gave rubbery electrolyte films without chemically crosslinked structure. The addition of the salt to TECs decreased the shear storage modulus at room temperature and expanded the temperature range of the rubbery plateau region within the range of salt concentrations studied here.

SD3212, a new antiarrhythmic drug, raises atrial fibrillation threshold in isolated rabbit hearts

SD3212 is a new antiarrhythmic drug which has class I, III, and IV effects. The purpose of this study was to elucidate the electrophysiological effects of this compound on a rabbit atrial fibrillation model, and to test a hypothesis that atrial fibrillation threshold is a quantitative indicator of atrial vulnerability. Whole hearts were excised from rabbits, and the aortas cannulated to perfuse the coronary arteries. Atrial fibrillation was induced with a burst stimulation of 50 Hz for 1 s while 3 microM acetylcholine (ACh) was perfused. When the right atrial appendage was paced at 200-ms intervals, SD3212 prolonged interatrial conduction time: control 30 +/- 1.2 ms, ACh 33 +/- 1.4 ms, ACh + SD 1 microM 37 +/- 2.4 ms, ACh + SD 3 microM 52 +/- 8.1 ms. The drug also prolonged the effective refractory period: control 80 +/-3.0 ms, ACh 48 +/- 3.8 ms, ACh + SD 1 microM 65 +/- 4.7 ms, ACh + SD 3 microM 98 +/- 15 ms. The rate of induction of atrial fibrillation by rapid pacing was 26% in Tyrode's solution, 85% in the presence of ACh, and 38% in the presence of ACh + SD 1 microM. The atrial fibrillation threshold decreased from 8.6 +/- 0.8mA (control) to 2.5 +/- 0.7 mA in the presence of ACh. It increased again to 7.8 +/- 1.0 mA in the presence of SD3212 (1 microM). SD3212 prolonged both the conduction time and refractory period. A reversed use-dependency was not prominent. These features caused antifibrillatory effects. Thus, the atrial fibrillation threshold seems to be a good quantitative indicator of atrial vulnerability.

The 1.5 A crystal structure of a bleomycin resistance determinant from bleomycin-producing Streptomyces verticillus

Bleomycin (Bm)-binding protein, designated BLMA, which is a Bm resistance determinant from Bm-producing Streptomyces verticillus, was crystallized in a form suitable for X-ray diffraction analysis. The diffraction intensity data were collected up to a resolution of 1.5 A with a merging R-value of 0.054 at a completeness of 94 %. The BLMA structure, determined by the single isomorphous replacement method including the anomalous scattering effect (SIR-AS) at a resolution of 2.0 A, was refined at 1.5 A resolution. The final R-factor was 19.0 % and R(free) was 22.1 % including 91 water molecules. The crystal packing showed a dimer form, which was generated by arm exchange. The 1.5 A high-resolution experiment allowed an analysis of the side-chain disorder of BLMA. The structural comparison of BLMA with a homologous protein from Streptoalloteichus hindustanus, designated Shble protein, showed that a Ser100-Gly103 loop was farther from the groove, which is a Bm-binding site, in BLMA than in the Shble protein. Furthermore the hydrophobicity of the groove in BLMA is much lower than that in the Shble protein. The structural differences between these proteins may be responsible for the observation that a half-saturating concentration (K(1/2)) of Bm is higher for BLMA than for the Shble protein.

Experimental investigations on relationships between myocardial damage and laser type used in transmyocardial laser revascularization (TMLR)

Transmyocardial laser revascularization (TMLR) using a CO2 laser is clinically attempted in end-stage ischemic heart disease that is not treated by conventional bypass grafting or transluminal angioplasty. Besides, clinical trials of TMLR using a Ho:YAG laser have started recently. In this study, we compared the degree of damage to normal myocardium using these 2 types of lasers. Hearts of adult mongrel dogs were exposed under general anesthesia. Dogs were divided into 2 groups; those with channels made in the left ventricle by CO2 laser (CO2 group, n = 5) and those with channels made by Ho:YAG laser (Ho:YAG group, n = 5). The chest was temporarily closed, then serum MB isozyme of creatinine kinase (CK-MB) and troponin T (TnT) were measured sequentially. Twenty-four hours after laser irradiation, hearts were isolated for pathological studies with hematoxylin-eosin and Masson's trichrome stains. The CO2 group produced CK-MB with a peak of 1162.2 +/- 462.2 IU/l and the Ho:YAG group 1804.0 +/- 992.4 IU/l after 12 hours, and there was a significant difference between two groups (p < 0.01). The CO2 group produced TnT with a peak of 1.2 +/- 0.4 ng/ml and the Ho:YAG group 11.6 +/- 4.1 ng/ml after 6 hours, and the peak value in Ho:YAG group was significantly higher than that in the CO2 group (p < 0.001). Thirty channels were confirmed histologically in the CO2 group, and the width of thermal damage layer around the channel lumen was 249 +/- 83 microns. Twenty-seven channels were confirmed histologically in the Ho:YAG group, and the width of thermal damage layer was 760 +/- 288 microns. Thermal damage in the Ho:YAG group was significant greater than that in the CO2 group (p < 0.01). We concluded that TMLR using a CO2 laser is more suitable for end-stage myocardial ischemia than a Ho:YAG laser in terms of myocardial damage.

Reperfusion in acute ischemic myocardium by transmyocardial revascularization using CO2 laser

Transmyocardial laser revascularization (TMLR) is currently applied to provide clinical benefits in the patients with end-stage coronary artery disease. However, this method is so far indicated only for chronic status of ischemic heart disease. In this study, we have investigated in the canine model whether acute ischemic myocardium could be reperfused by TMLR using CO2 laser. A CO2 laser was used to create transmural myocardial channels. The ischemic areas of 3 cm in diameter were created on the left ventricle with multiple coronary ligations. Laser procedure was carried out 30 minutes after coronary ligation in TMLR group (n = 6), while laser treatment was not performed after coronary ligation in acute myocardial infarction (AMI) group (n = 6). The level of MB isozyme of creatinine kinase (CK-MB) derived from coronary sinus was measured at 0, 3, 6, 12, 18, 24, and 48 hours after coronary ligations, and the pattern of serial CK-MB changing was analyzed. Animals were sacrificed 48 hours after treatment and histologically investigated. The time to peak level of CK-MB in TMLR group appeared significantly earlier (13.0 +/- 2.4 hours) than that in AMI group (22.0 +/- 3.1 hours). The value of CK-MB of 24 hours after ligation in TMLR group (1985 +/- 805 IU/L) was significantly lower than that in AMI group (4759 +/- 778 IU/L). The channels on the gross section after 48 hours of TMLR were patent with some of fibrin network. Red blood cells were scattered in the lumens. It was suggested that acute ischemic myocardium was directly reperfused through the open laser channels from the left ventricular chamber in the canine model.

Crystallization and preliminary X-ray diffraction studies of bleomycin-binding protein encoded on the transposon Tn5

A bleomycin-binding protein, designated BLMT, encoded on the transposon Tn5 was crystallized using the vapour-diffusion method in a form suitable for X-ray diffraction analysis. Crystals were grown at pH 6.5 in 0.1 M sodium cacodylate and 0.2 M calcium acetate, using 25% PEG 6000 as a precipitant. They belong to the orthorhombic system, space group C2221, with unit-cell dimensions a = 81.56, b = 85.25, c = 78.91 A and one dimer in the asymmetric unit. The diffraction intensity data were collected on beamline 18B of the Photon Factory to 2.0 A resolution with a merging R value of 0.052. The diffraction data set is 91% complete.

Pathological analysis of transmyocardial laser revascularization for acute myocardial ischemia

Transmyocardial laser revascularization (TMLR) is an alternative surgical procedure for the patients with intractable coronary artery disease. Efficacy of the treatment has been established, however, the mechanism of TMLR is still controversial. In this study, we investigated the effect of TMLR on acute myocardial ischemia with pathological analysis. Under general anesthesia, the hearts of mongrel dogs were exposed. Then, the anterior descending branch of the left coronary artery was ligated to make the ischemic area on the left ventricle. Laser punctures were made 30 minutes after coronary ligation in the TMLR group (n = 5), and no further procedure was performed after coronary ligation in the AMI group (n = 5). One month after these operations, the hearts were extirpated for pathological studies. The avascular area and the viable area in the infarcted area were macroscopically separated by Evans blue dye and triphenyltetrazolium chloride (TTC) staining. Thickness of the left ventricular wall in the infarcted area was also measured and compared. Furthermore, all of the infarcted area and the lased area were microscopically examined with Masson's trichrome stain. The size of the infarcted area in the TMLR group was smaller than that in the AMI group. It was significantly different (p < 0.05) in the basal and apical regions. As a result, the ratio of the viable area by the avascular area was larger in the TMLR group than in the AMI group. It was significantly different (p < 0.05) in the apical region. In the basal region, the thickness of the left ventricle in the AMI group was thinner than that of untreated dogs (normal group: n = 5), and there was no difference between the normal group and the TMLR group. Whereas in the apical region, significant difference of the thickness was found among AMI, TMLR, and normal groups (p < 0.05). In conclusion, our study supported; 1) TMLR reduced overall infarcted size, and increased the viable area in the infarcted area, 2) TMLR prevented the thinning of the left ventricular wall.

Enhancement of in vivo binding of [123I]beta-CIT by MK-801 in rat brain

The effects of MK-801, a noncompetitive NMDA receptor antagonist, on in vivo and in vitro binding of radioactive iodine ([123I] or [125I]) labeled beta-CIT [RTI-55, 3beta-(4-iodophenyl)tropane-2beta-carboxylic acid methyl ester] were investigated in rat brain. In the in vitro binding study, 10 pM of [125I]beta-CIT was incubated with either 0.03 microM or 3 microM of MK-801 at 24 degrees C for 60 min. In vitro, no alterations in [125I]beta-CIT binding in any region of rat brain slices were detected after addition of MK-801. In the in vivo binding study, [123I]beta-CIT was intravenously injected into rats 30 min after intraperitoneal injection of 0.03-1 mg/kg of MK-801. The in vivo [123I]beta-CIT binding in the striatum, frontal cortex, occipital cortex, hypothalamus, and thalamus was significantly increased by pretreatment with 1 mg/kg of MK-801. Kinetic analysis using the cerebellum as a reference region revealed that the increases in in vivo [123I]beta-CIT binding induced by MK-801 were mainly due to increases in both input rate constant k3 and output rate constant k4. The results of this study indicate that the glutamatergic system, including NMDA receptor, plays an important role in regulating neurotransmission in the dopaminergic or serotonergic systems in intact brain.

Cloning of rat dihydropyrimidine dehydrogenase and correlation of its mRNA increase in the rat liver with age

Overlapping cDNAs encoding dihydropyrimidine dehydrogenase (DPD), the rate-limiting enzyme of pyrimidine degradation, were isolated from a rat liver cDNA library, and a 4,353 bp cDNA sequence with a 3,075 bp open reading frame encoding a polypeptide of 1,025 residues with a molecular mass of 111,458 Da was determined. Western blot analysis of COS-7 cells that were transfected with an RT-PCR-derived DPD cDNA showed that the product from the cDNA binds to an anti-serum for DPD. Northern blot analysis was performed by using a partial fragment of the cloned cDNA as a probe. The mRNA level, the protein level, and the activity of DPD in the rat liver increased to the adult level by 3 mo of age. The levels of DPD in the liver of adrenalectomized rats increased 48 h after glucocorticoid administration. The increase of DPD after birth may be caused by the increase in glucocorticoid level.

Mitral valve replacement in a patient with an extensively calcified mitral anulus: report of a case

We report herein the case of a patient with chronic renal failure in whom mitral valve stenosis with extensive mitral anular calcification involving the entire anulus and leaflets was successfully treated surgically. Excision of both leaflets and partial resection of the anular calcification enabled the insertion of a 23-mm St. Jude Medical prosthetic valve. The technical difficulties involved with inserting the appropriate-sized prosthetic valve in a narrowed mitral anulus with heavy calcification are discussed following this case report.