Mitochondrial Responses to Sublethal Doxorubicin in H9c2 Cardiomyocytes: The Role of Phosphorylated CaMKII

Background

Doxorubicin (Dox) is effective against different types of cancers, but it poses cardiotoxic side effects, frequently resulting in irreversible heart failure. However, the complexities surrounding this cardiotoxicity, especially at sublethal dosages, remain to be fully elucidated. We investigated early cellular disruptions in response to sublethal Dox, with a specific emphasis on the role of phosphorylated calcium/calmodulin-dependent protein kinase II (CaMKII) in initiating mitochondrial dysfunction.

Methods

This study utilized the H9c2 cardiomyocyte model to identify a sublethal concentration of Dox and investigate its impact on mitochondrial health using markers such as mitochondrial membrane potential (MMP), mitophagy initiation, and mitochondrial calcium dynamics. We examined the roles of and interactions between CaMKII, dynamin-related protein 1 (Drp1), and the mitochondrial calcium uniporter (MCU) in Dox-induced mitochondrial disruption using specific inhibitors, such as KN-93, Mdivi-1, and Ru360, respectively.

Results

Exposure to a sublethal dose of Dox reduced the MMP red-to-green fluorescence ratio in H9c2 cells by 40.6% compared with vehicle, and increased the proportion of cells undergoing mitophagy from negligible levels compared with vehicle to 62.2%. Mitochondrial calcium levels also increased by 8.7-fold compared with the vehicle group. Notably, the activation of CaMKII, particularly its phosphorylated form, was pivotal in driving these mitochondrial changes, as inhibition using KN-93 restored MMP and decreased mitophagy. However, inhibition of Drp1 and MCU functions had a limited impact on the observed mitochondrial disruptions.

Conclusion

Sublethal administration of Dox is closely linked to CaMKII activation through phosphorylation, emphasizing its pivotal role in early mitochondrial disruption. These findings present a promising direction for developing therapeutic strategies that may alleviate the cardiotoxic effects of Dox, potentially increasing its clinical efficacy.

Inhibition of the uric acid efflux transporter ABCG2 enhances stimulating effect of soluble uric acid on IL-1β production in murine macrophage-like J774.1 cells

Soluble uric acid (UA) absorbed by cells through UA transporters (UATs) accumulates intracellularly, activates the NLRP3 inflammasome and thereby increases IL-1β secretion. ABCG2 transporter excludes intracellular UA. However, it remains unknown whether ABCG2 inhibition leads to intracellular accumulation of UA and increases IL-1β production. In this study, we examined whether genetic and pharmacological inhibition of ABCG2 could increase IL-1β production in mouse macrophage-like J774.1 cells especially under hyperuricemic conditions. We determined mRNA and protein levels of pro-IL-1β, mature IL-1β, caspase-1 and several UATs in culture supernatants and lysates of J774.1 cells with or without soluble UA pretreatment. Knockdown experiments using an shRNA against ABCG2 and pharmacological experiments with an ABCG2 inhibitor were conducted. Extracellularly applied soluble UA increased protein levels of pro-IL-1β, mature IL-1β and caspase-1 in the culture supernatant from lipopolysaccharide (LPS)-primed and monosodium urate crystal (MSU)-stimulated J774.1 cells. J774.1 cells expressed UATs of ABCG2, GLUT9 and MRP4, and shRNA knockdown of ABCG2 increased protein levels of pro-IL-1β and mature IL-1β in the culture supernatant. Soluble UA increased mRNA and protein levels of ABCG2 in J774.1 cells without either LPS or MSU treatment. An ABCG2 inhibitor, febuxostat, but not a urate reabsorption inhibitor, dotinurad, enhanced IL-1β production in cells pretreated with soluble UA. In conclusion, genetic and pharmacological inhibition of ABCG2 enhanced IL-1β production especially under hyperuricemic conditions by increasing intracellularly accumulated soluble UA that activates the NLRP3 inflammasome and pro-IL-1β transcription in macrophage-like J774.1 cells.

[Gut microbiota and cardiovascular disease-insights into the potential and challenges of drug discovery]

Cardiovascular disease is a major cause of death worldwide, with high prevalence and morbidity. Recent advances in technology have reported that abnormalities in the gut microbiota are associated with a variety of diseases, including cardiovascular diseases. The gut microbiota is a complex ecosystem that plays an important role in maintaining host health. It has been reported that the imbalance of gut microbiota causes changes in the production of substances derived from gut bacteria, such as short-chain fatty acids, trimethylamine-N-oxide, and lipopolysaccharide, and contributes to the development of cardiovascular diseases. In the drug discovery, it is a promising approach to prevention and therapy of the cardiovascular disease to focus on the relation between gut and heart, such as gut bacteria. However, there are challenges that must be overcome to convert this approach into effective therapy. In this review, we focus on cardiovascular diseases, particularly atherosclerotic disease, heart failure, and atrial fibrillation, and discuss the relationship between gut bacteria and substances derived from gut bacteria in cardiovascular disease. We also discuss the challenges and potential of drug discovery targeting the gut-heart relationship for the treatment and prevention of cardiovascular disease.

No significant association between stable iodine intake and thyroid dysfunction in children after the Fukushima Nuclear Disaster: an observational study

PURPOSE

Stable iodine prophylaxis helps prevent childhood thyroid cancer in nuclear emergencies; however, there is limited information on its effect on thyroid function. This study aimed to examine thyroid function and autoimmunity among children and adolescents that took stable iodine after the Fukushima Nuclear Disaster.

METHODS

For this observational study, data were obtained from children and adolescents that underwent thyroid cancer screening at Hirata Central Hospital from April 2012 to March 2018. Participant characteristics, including possible hypothyroidism and hyperthyroidism, were compared between the prophylaxis and no-prophylaxis groups. Multivariable logistic regression models were used to assess for possible hypothyroidism, autoantibodies positive, and hyperthyroidism.

RESULTS

A total of 1,225 participants with stable iodine prophylaxis and 3,946 without prophylaxis were enrolled. Of those participants, blood samples were available for 144 and 1,201 participants in the prophylaxis and no-prophylaxis groups, respectively. There were 17 (11.8%) and 146 cases (12.2%) of possible hypothyroidism or autoantibodies positive cases in the prophylaxis and no-prophylaxis groups, respectively, and there were no cases and 3 cases (0.2%) of possible hyperthyroidism in those two groups, respectively. Multivariable analysis for possible hypothyroidism revealed no association between stable iodine intake and possible hypothyroidism or autoantibodies positive [odds ratio 0.716 (95% confidence interval 0.399-1.284)] (p = 0.262). We did not perform multivariable analysis for hyperthyroidism due to the limited number of cases.

CONCLUSION

Significant adverse effects of stable iodine intake on thyroid function were not observed among children and adolescents 7 years after the Fukushima Nuclear Disaster.

Preventive effects of nitrate-rich beetroot juice supplementation on monocrotaline-induced pulmonary hypertension in rats

Beetroot (Beta vulgaris L.) has a high level of nitrate; therefore, its dietary intake could increase nitric oxide (NO) level in the body, possibly preventing the development of pulmonary hypertension (PH). In this study, we examined the effects of beetroot juice (BJ) supplementation on PH and the contribution of nitrate to such effects using a rat model of monocrotaline (MCT, 60 mg/kg s.c.)-induced PH. Rats were injected subcutaneously with saline or 60 mg/kg MCT and were sacrificed 28 days after the injection. In some rats injected with MCT, BJ was supplemented from the day of MCT injection to the day of sacrifice. First, MCT-induced right ventricular systolic pressure elevation, pulmonary arterial medial thickening and muscularization, and right ventricular hypertrophy were suppressed by supplementation with low-dose BJ (nitrate: 1.3 mmol/L) but not high-dose BJ (nitrate: 4.3 mmol/L). Of the plasma nitrite, nitrate, and their sum (NOx) levels, only the nitrate levels were found to be increased by the high-dose BJ supplementation. Second, in order to clarify the possible involvement of nitrate in the preventive effects of BJ on PH symptoms, the effects of nitrate-rich BJ (nitrate: 0.9 mmol/L) supplementation were compared with those of the nitrate-depleted BJ. While the former exerted preventive effects on PH symptoms, such effects were not observed in rats supplemented with nitrate-depleted BJ. Neither supplementation with nitrate-rich nor nitrate-depleted BJ affected plasma nitrite, nitrate, and NOx levels. These findings suggest that a suitable amount of BJ ingestion, which does not affect systemic NO levels, can prevent the development of PH in a nitrate-dependent manner. Therefore, BJ could be highly useful as a therapy in patients with PH.

Cardioprotective Effects of a Nonsteroidal Mineralocorticoid Receptor Blocker, Esaxerenone, in Dahl Salt-Sensitive Hypertensive Rats

We investigated the effects of esaxerenone, a novel, nonsteroidal, and selective mineralocorticoid receptor blocker, on cardiac function in Dahl salt-sensitive (DSS) rats. We provided 6-week-old DSS rats a high-salt diet (HSD, 8% NaCl). Following six weeks of HSD feeding (establishment of cardiac hypertrophy), we divided the animals into the following two groups: HSD or HSD + esaxerenone (0.001%, w/w). In survival study, all HSD-fed animals died by 24 weeks of age, whereas the esaxerenone-treated HSD-fed animals showed significantly improved survival. We used the same protocol with a separate set of animals to evaluate the cardiac function by echocardiography after four weeks of treatment. The results showed that HSD-fed animals developed cardiac dysfunction as evidenced by reduced stroke volume, ejection fraction, and cardiac output. Importantly, esaxerenone treatment decreased the worsening of cardiac dysfunction concomitant with a significantly reduced level of systolic blood pressure. In addition, treatment with esaxerenone in HSD-fed DSS rats caused a reduced level of cardiac remodeling as well as fibrosis. Furthermore, inflammation and oxidative stress were significantly reduced. These data indicate that esaxerenone has the potential to mitigate cardiac dysfunction in salt-induced myocardial injury in rats.

MicroRNA-494-3p inhibits formation of fast oxidative muscle fibres by targeting E1A-binding protein p300 in human-induced pluripotent stem cells

MYOD-induced microRNA-494-3p expression inhibits fast oxidative myotube formation by downregulating myosin heavy chain 2 (MYH2) in human induced pluripotent stem cells (hiPSCs) during skeletal myogenesis. However, the molecular mechanisms regulating MYH2 expression via miR-494-3p remain unknown. Here, using bioinformatic analyses, we show that miR-494-3p potentially targets the transcript of the E1A-binding protein p300 at its 3'-untranslated region (UTR). Myogenesis in hiPSCs with the Tet/ON-myogenic differentiation 1 (MYOD1) gene (MyoD-hiPSCs) was induced by culturing them in doxycycline-supplemented differentiation medium for 7 days. p300 protein expression decreased after transient induction of miR-494-3p during myogenesis. miR-494-3p mimics decreased the levels of p300 and its downstream targets MYOD and MYH2 and myotube formation efficiency. p300 knockdown decreased myotube formation efficiency, MYH2 expression, and basal oxygen consumption rate. The binding of miR-494-3p to the wild type p300 3'-UTR, but not the mutated site, was confirmed using luciferase assay. Overexpression of p300 rescued the miR-494-3p mimic-induced phenotype in MyoD-hiPSCs. Moreover, miR-494-3p mimic reduced the levels of p300, MYOD, and MYH2 in skeletal muscles in mice. Thus, miR-494-3p might modulate MYH2 expression and fast oxidative myotube formation by directly regulating p300 levels during skeletal myogenesis in MyoD-hiPSCs and murine skeletal muscle tissues.

Underestimation of COVID-19 cases in Japan: an analysis of RT-PCR testing for COVID-19 among 47 prefectures in Japan

BACKGROUND

Under the unique Japanese policy to restrict reverse transcriptase-polymerase chain reaction (RT-PCR) testing against severe acute respiratory syndrome coronavirus 2, a nationwide number of its confirmed cases and mortality remains to be low. Yet the information is lacking on geographical differences of these measures and their associated factors.

AIM

Evaluation of prefecture-based geographical differences and associated predictors for the incidence and number of RT-PCR tests for coronavirus disease 2019 (COVID-19).

DESIGN

Cross-sectional study using regression and correlation analysis.

METHODS

We retrieved domestic laboratory-confirmed cases, deaths and the number of RT-PCR testing for COVID-19 from 15 January to 6 April 2020 in 47 prefectures in Japan, using publicly available data by the Ministry of Health, Labour and Welfare. We did descriptive analyses of these three measures and identified significant predictors for the incidence and RT-PCR testing through multiple regression analyses and correlates with the number of deaths through correlation analysis.

RESULTS

The median prefectural-level incidence and number of RT-PCR testing per 100 000 population were 1.14 and 38.6, respectively. Multiple regression analyses revealed that significant predictors for the incidence were prefectural-level population (P < 0.001) and the number of RT-PCR testing (P = 0.03); and those for RT-PCR testing were the incidence (P = 0.025), available beds (P = 0.045) and cluster infections (P = 0.034).

CONCLUSION

Considering bidirectional association between the incidence and RT-PCR testing, there may have been an underdiagnosed population for the infection. The restraint policy for RT-PCR testing should be revisited to meet the increasing demand under the COVID-19 epidemic.

Effects of Beet Juice Supplementation on Monocrotaline-Induced Pulmonary Hypertension in Rats

BACKGROUND

Recently, attention has been focused on the cardiovascular protective effects of beet juice (BJ) with high amounts of nitrate. In this study, we examined the effect of BJ supplementation in a rat model of monocrotaline (MCT)-induced pulmonary hypertension (PH).

METHODS

MCT (60 mg/kg) was subcutaneously administered to rats, and BJ (prepared by dissolving BJ powder at a concentration of 1 g/l or 10 g/l in drinking water) supplementation was started from the day of, 1 week before, and 2 weeks after MCT injection. Saline-injected rats given drinking water were used as controls.

RESULTS

Low-dose BJ supplementation starting from the day of MCT injection exerted protective effects on the MCT-induced elevation of right ventricular systolic pressure, right ventricular hypertrophy, and pulmonary arterial remodeling, without causing a significant increase in plasma nitrite plus nitrate (NOx) levels. On the other hand, such beneficial effects were not observed with high-dose BJ supplementation, although the NOx levels were slightly higher than those in the low-dose group. In addition, low-dose BJ supplementation starting from 1 week before MCT injection did not improve PH symptoms, as described above. Furthermore, low-dose BJ supplementation starting from 2 weeks after MCT injection was ineffective against functional and morphological alterations in pulmonary circulation associated with MCT-induced PH.

CONCLUSIONS

Habitual ingestion of a suitable amount of BJ could be a potential option for preventing PH. However, beneficial effects cannot be expected when PH has developed to some degree.

Development of the micro pixel chamber based on MEMS technology

Micro pixel chambers (μ-PIC) are gaseous two-dimensional imaging detectors originally manufactured using printed circuit board (PCB) technology. They are used in MeV gamma-ray astronomy, medicalimaging, neutron imaging, the search for dark matter, and dose monitoring. The position resolution of the present μ-PIC is approximately 120 μm (RMS), however some applications require a fine position resolution of less than 100 μm. To this end, we have started to develop a μ-PIC based on micro electro mechanical system (MEMS) technology, which provides better manufacturing accuracy than PCB technology. Our simulation predicted the gains of MEMS μ-PICs to be twice those of PCB μ-PICs at the same anode voltage. We manufactured two MEMS μ-PICs and tested them to study their behavior. In these experiments, we successfully operated the fabricatedMEMS μ-PICs and we achieved a maximum gain of approximately 7×103 and collected their energy spectra under irradiation of X-rays from 55Fe. However, the measured gains of the MEMS μ-PICs were less than half of the values predicted in the simulations. We postulated that the gains of the MEMS μ-PICs are diminished by the effect of the silicon used as a semiconducting substrate.

Abstract P3-10-14: Breast cancer provider delay after the 2011 triple disaster in Fukushima, Japan

Introduction

Timely diagnosis and treatment is an indispensable part of breast cancer management. Delay of this process, also known as provider delay, can result in a deteriorated prognosis of affected patients. Although it has been suggested that disasters can impact cancer care and extend provider delay, there is little information available on long-term trends of breast cancer provider delay in post-disaster settings.

So-so district of Fukushima prefecture, Japan, experienced an earthquake, tsunami and the Fukushima Daiichi Nuclear Power Plant Accident in 2011. So-so district has areas falling within the mandatory, voluntary and non-evacuation ordered zones. Due to a long-term shortage of medical staff and closure of medical institutions post-disaster, patients with breast cancer may have experienced longer provider delay in this area.

Objectives

To compare provider delay of breast cancer patients and elucidate contributing factors to delay pre- and post-disaster, in an area severely affected by Japan's 2011 triple disaster.

Methods

We retrospectively investigated data of newly diagnosed breast cancer patients who undertook first medical consultation at the two main cancer centers in the non-evacuation ordered zone of So-so district from 2005 to 2016. Sociodemographic and clinical information was collected from medical records. The main outcome measure was median (days) from first medical consultation to start of breast cancer-specific treatment, pre- and post-disaster, using Mann-Whitney U test. Multivariate linear regression was then conducted to identify any factors which contributed to extended provider delay before and after the disaster.

Results

A total of 157 pre-disaster patients and 121 post-disaster patients were included in the study. There was no significant difference in the interval of median days of first medical consultation to start of first treatment pre- and post-disaster (40 vs. 39, p=0.82). Although diagnosis was made in a shorter interval post-disaster compared to pre-disaster (11 vs. 14, p=0.01) with significantly smaller median number of biopsies (1 vs. 1, p=0.001), this post-disaster improvement in diagnostic process was offset by deferred start of treatment after diagnosis (26 vs. 22, p=0.008). Among the pre-disaster patients, cancer detection by breast cancer screening program (p&lt;0.001), being engaged in full-time job (p&lt;0.042), and number of biopsies before diagnosis (p=0.005) contributed to longer provider delay in multivariate regression. However, consultation from other medical providers (p=0.03) was the only factor which significantly contributed to extended delay post-disaster, after controlling for multiple variables.

Conclusion

There was no significant increase in provider delay among breast cancer patients post-disaster. However, a median interval of 39 days from first medical consultation to start of treatment is much longer than other high-income countries, and shows much room for improvement in future.Introduction

Timely diagnosis and treatment is an indispensable part of breast cancer management. Delay of this process, also known as provider delay, can result in a deteriorated prognosis of affected patients. Although it has been suggested that disasters can impact cancer care and extend provider delay, there is little information available on long-term trends of breast cancer provider delay in post-disaster settings.

So-so district of Fukushima prefecture, Japan, experienced an earthquake, tsunami and the Fukushima Daiichi Nuclear Power Plant Accident in 2011. So-so district has areas falling within the mandatory, voluntary and non-evacuation ordered zones. Due to a long-term shortage of medical staff and closure of medical institutions post-disaster, patients with breast cancer may have experienced longer provider delay in this area.

Objectives

To compare provider delay of breast cancer patients and elucidate contributing factors to delay pre- and post-disaster, in an area severely affected by Japan's 2011 triple disaster.

Methods

We retrospectively investigated data of newly diagnosed breast cancer patients who undertook first medical consultation at the two main cancer centers in the non-evacuation ordered zone of So-so district from 2005 to 2016. Sociodemographic and clinical information was collected from medical records. The main outcome measure was median (days) from first medical consultation to start of breast cancer-specific treatment, pre- and post-disaster, using Mann-Whitney U test. Multivariate linear regression was then conducted to identify any factors which contributed to extended provider delay before and after the disaster.

Results

A total of 157 pre-disaster patients and 121 post-disaster patients were included in the study. There was no significant difference in the interval of median days of first medical consultation to start of first treatment pre- and post-disaster (40 vs. 39, p=0.82). Although diagnosis was made in a shorter interval post-disaster compared to pre-disaster (11 vs. 14, p=0.01) with significantly smaller median number of biopsies (1 vs. 1, p=0.001), this post-disaster improvement in diagnostic process was offset by deferred start of treatment after diagnosis (26 vs. 22, p=0.008). Among the pre-disaster patients, cancer detection by breast cancer screening program (p&lt;0.001), being engaged in full-time job (p&lt;0.042), and number of biopsies before diagnosis (p=0.005) contributed to longer provider delay in multivariate regression. However, consultation from other medical providers (p=0.03) was the only factor which significantly contributed to extended delay post-disaster, after controlling for multiple variables.

Conclusion

There was no significant increase in provider delay among breast cancer patients post-disaster. However, a median interval of 39 days from first medical consultation to start of treatment is much longer than other high-income countries, and shows much room for improvement in future.

Citation Format: Ozaki A, Leppold C, Tsubokura M, Sawano T, Tsukada M, Ohira H. Breast cancer provider delay after the 2011 triple disaster in Fukushima, Japan [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-10-14.

Establishment of Imaging Spectroscopy of Nuclear Gamma-Rays based on Geometrical Optics

Since the discovery of nuclear gamma-rays, its imaging has been limited to pseudo imaging, such as Compton Camera (CC) and coded mask. Pseudo imaging does not keep physical information (intensity, or brightness in Optics) along a ray, and thus is capable of no more than qualitative imaging of bright objects. To attain quantitative imaging, cameras that realize geometrical optics is essential, which would be, for nuclear MeV gammas, only possible via complete reconstruction of the Compton process. Recently we have revealed that "Electron Tracking Compton Camera" (ETCC) provides a well-defined Point Spread Function (PSF). The information of an incoming gamma is kept along a ray with the PSF and that is equivalent to geometrical optics. Here we present an imaging-spectroscopic measurement with the ETCC. Our results highlight the intrinsic difficulty with CCs in performing accurate imaging, and show that the ETCC surmounts this problem. The imaging capability also helps the ETCC suppress the noise level dramatically by ~3 orders of magnitude without a shielding structure. Furthermore, full reconstruction of Compton process with the ETCC provides spectra free of Compton edges. These results mark the first proper imaging of nuclear gammas based on the genuine geometrical optics.

Characterization of Ruminococcus albus cellodextrin phosphorylase and identification of a key phenylalanine residue for acceptor specificity and affinity to the phosphate group

Ruminococcus albus has the ability to intracellularly degrade cello-oligosaccharides primarily via phosphorolysis. In this study, the enzymatic characteristics of R. albus cellodextrin phosphorylase (RaCDP), which is a member of glycoside hydrolase family 94, was investigated. RaCDP catalyzes the phosphorolysis of cellotriose through an ordered 'bi bi' mechanism in which cellotriose binds to RaCDP before inorganic phosphate, and then cellobiose and glucose 1-phosphate (Glc1P) are released in that order. Among the cello-oligosaccharides tested, RaCDP had the highest phosphorolytic and synthetic activities towards cellohexaose and cellopentaose, respectively. RaCDP successively transferred glucosyl residues from Glc1P to the growing cello-oligosaccharide chain, and insoluble cello-oligosaccharides comprising a mean of eight residues were produced. Sophorose, laminaribiose, β-1,4-xylobiose, β-1,4-mannobiose and cellobiitol served as acceptors for RaCDP. RaCDP had very low affinity for phosphate groups in both the phosphorolysis and synthesis directions. A sequence comparison revealed that RaCDP has Gln at position 646 where His is normally conserved in the phosphate binding sites of related enzymes. A Q646H mutant showed approximately twofold lower apparent K(m) values for inorganic phosphate and Glc1P than the wild-type. RaCDP has Phe at position 633 corresponding to Tyr and Val in the +1 subsites of cellobiose phosphorylase and N,N'-diacetylchitobiose phosphorylase, respectively. A F633Y mutant showed higher preference for cellobiose over β-1,4-mannobiose as an acceptor substrate in the synthetic reaction than the wild-type. Furthermore, the F633Y mutant showed 75- and 1100-fold lower apparent Km values for inorganic phosphate and Glc1P, respectively, in phosphorolysis and synthesis of cellotriose.

Role of superoxide production in post-ischemic cardiac dysfunction and norepinephrine overflow in rat hearts

Reactive oxygen species and norepinephrine are known as physiological active substances which cause cell damage and cardiac dysfunction in myocardial ischemia/reperfusion injury. We investigated the role of reactive oxygen species, especially superoxide (O2(-)), in ischemia-induced norepinephrine overflow and cardiac dysfunction using superoxide scavengers tempol and tiron. According to the Langendorff technique, isolated rat hearts were subjected to 40-min global ischemia followed by 30-min reperfusion. Tempol (10 and 100 µM) and tiron (100 and 500 µM) were perfused 15 min before ischemia and during reperfusion. Cardiac levels of oxidative stress markers such as O2(-) and malondialdehyde were notably increased during ischemia and following reperfusion, which were suppressed by the administration of tempol or tiron. These agents significantly improved ischemia/reperfusion-induced cardiac dysfunction such as decreased left ventricular developed pressure and the maximum and minimum value of the first derivative of left ventricular pressure and increased left ventricular end-diastolic pressure. Furthermore, norepinephrine overflow in the coronary effluent after ischemia/reperfusion was significantly suppressed by the administration of each agent. These results suggest that endogenously increased O2(-) is involved in norepinephrine overflow and cardiac dysfunction after myocardial ischemia/reperfusion.

Whole genome sequencing of meticillin-resistant Staphylococcus aureus

BACKGROUND

Staphylococcus aureus is one of the major causes of community-acquired and hospital-acquired infections. It produces numerous toxins including superantigens that cause unique disease entities such as toxic-shock syndrome and staphylococcal scarlet fever, and has acquired resistance to practically all antibiotics. Whole genome analysis is a necessary step towards future development of countermeasures against this organism.

METHODS

Whole genome sequences of two related S aureus strains (N315 and Mu50) were determined by shot-gun random sequencing. N315 is a meticillin-resistant S aureus (MRSA) strain isolated in 1982, and Mu50 is an MRSA strain with vancomycin resistance isolated in 1997. The open reading frames were identified by use of GAMBLER and GLIMMER programs, and annotation of each was done with a BLAST homology search, motif analysis, and protein localisation prediction.

FINDINGS

The Staphylococcus genome was composed of a complex mixture of genes, many of which seem to have been acquired by lateral gene transfer. Most of the antibiotic resistance genes were carried either by plasmids or by mobile genetic elements including a unique resistance island. Three classes of new pathogenicity islands were identified in the genome: a toxic-shock-syndrome toxin island family, exotoxin islands, and enterotoxin islands. In the latter two pathogenicity islands, clusters of exotoxin and enterotoxin genes were found closely linked with other gene clusters encoding putative pathogenic factors. The analysis also identified 70 candidates for new virulence factors.

INTERPRETATION

The remarkable ability of S aureus to acquire useful genes from various organisms was revealed through the observation of genome complexity and evidence of lateral gene transfer. Repeated duplication of genes encoding superantigens explains why S aureus is capable of infecting humans of diverse genetic backgrounds, eliciting severe immune reactions. Investigation of many newly identified gene products, including the 70 putative virulence factors, will greatly improve our understanding of the biology of staphylococci and the processes of infectious diseases caused by S aureus.

Hepatic coma recovered after interventional obliteration for ileocecal-inferior vena cava shunt--report of one case

We performed interventional angiography (IVA) in a patient with liver cirrhosis (LC) and hepatoma (HCC) who experienced repeated attacks of unconsciousness due to hyperammonemia caused by ileocecal-inferior vena cava (IC-IVC) shunt and succeeded in the treatment. We report the results below. The patient, 53-year-old male, underwent endoscopic injection sclerotherapy for esophageal varix due to LC followed by splenectomy for pancytopenia in 1986. He made good progress. However intraarterial anticancer therapy was conducted for HCC in 1994. From that time hepatic coma began to appear and its frequency gradually increased. Hepatic coma occurred once every 3 weeks from June 1996. He was thus admitted to our hospital. Hematobiochemical testes showed that ammonia level was 297 mcg/dl. Albumin 2.8d/dl, and Total-Bilirubin 10.78 mg/dl. Arterioportography from superior mesenteric artery showed most of portal blood flowed away from the liver though the ileocolic vein to IVC. We decided to conduct IVA for treatment. Specially, a 6Fr balloon catheter was inserted from the right inguinal region into a shunt to the portal vein though IVC by the Seldinger technique. The balloon was inflated in the shunt to close the shunt. Six ml of 5% ethanolamime oleate with iopamidol was injected because retrograde angiography showed that iopamidol was flowed out via testicular vein to IVC. The balloon catheter was retained for 24 hours. Angiography, conducted from the catheter again 24 hours later, showed that the shunt was occluded, blood ammonia level was 71 mcg/dl after occlusion. Hepatic coma was not observed after treatment. We encountered a very rare case who repeated hepatic comas due to IC-IVC shunt and recovered dramatically after IVA.

An improved endoscopic variceal ligation for esophageal and solitary gastric varices--three-O-band-shooter

We have reported a 16.0 mm long new type of instrument with the inner diameter of inner cylinder of 10.3 mm for endoscopic variceal ligation which could shoot 3 elastic O bands continuously in short period of time without removing the endoscope. The suction volume of new instrument is larger than that of the Stiegmann's ligator. We performed endoscopic variceal ligation (EVL) in 17 cases of the esophageal varix and 8 cases of the solitary gastric varix. EVL was performed as prophylaxis as all the cases. The esophageal varices were eliminated in all the cases after ulcer formation. The procedure was performed one time in 15 cases and two times in the remaining 2 cases. Three patients died one to hepatic failure during the follow-up period between 4 and 16 months. Six and twelve months cumulative recurrence rates were 30% and 48% respectively. On the other hand all the gastric varices disappeared after one sitting of the treatment. There was one variceal recurrence during the follow-up period. Computed tomography and/or arterioportography performed before had showed patent gastro-renal shunt in five cases. No change in the shunt was observed after the treatment. No serious complications due to EVL was encountered in all the cases. Therefore, it is thought that this method can be used for the treatment of not only esophageal varices but also gastric varices.

Mitochondrial DNA mutations associated with the 11778 mutation in Leber's disease

To clarify the characteristics of possible synergestic mitochondrial DNA (mtDNA) mutations associated with Leber's hereditary optic neuropathy (LHON), we analyzed the entire nucleotide sequences of mitochondrial genome of two Japanese patients from independent pedigrees harboring the 11778 mtDNA mutation, and compared their sequences with those of 47 disease and 6 normal controls. We have detected several unique mutations in the mtDNA in addition to the 11778 mutation. Two nucleotide substitutions, an A-to-G transition at position 856 in the 12S rRNA gene and an A-to-G transition at 14692 in the T psi C loop of the tRNA(Glu) gene, occurred at highly conserved sites among various species. These mutations in combination with the 11778 mutation might synergetically contribute to the pathogenesis of LHON.

[The efficacy and side effects of chemotherapy for primary lung cancer with cisplatin and etoposide]

We treated 34 primary lung cancer patients with chemotherapy of cisplatin and etoposide. There were 2 cases of CR (15%) and 8 cases of PR (61%) out of 13 cases of small cell lung cancer. No case of CR and one case of PR (5%) were obtained out of 21 cases of non-small cell cancer. Side effects were leukopenia, increase of BUN and creatinine, angina pectoris, supraventricular premature contraction, and renal failure. WBC reached nadir on day 15 on average. When we repeated this regimen, we encountered 3 cases of acute myocardial infarction, and it was useful for small cell lung cancer.

[CDDP-containing combination chemotherapy for advanced lung cancer]

The effect and toxicities of Cis-containing combination chemotherapy were tested in 28 patients with primary lung cancer. All patients were treated with 80 mg/m2 Cisplatinum on the first day and 750 mg ftorafur p.o. every day. In addition to these drugs, patients with squamous cell cancer were treated with continuous subcutaneous infusion of 4 mg/m2 Peplomycin for 5 days and one shot i.v. of 4 mg MMC. Patients with adeno- and large cell cancer were treated with 30 mg/m2 Adriamycin and 4 mg MMC, while patients with small cell cancer were given 150 mg/m2 VP-16 p.o. for 5 days. The following results were obtained. Of 22 evaluable patients, overall response rate was 50%. In each histologic type, response rate was 50% (5/10) for squamous cell carcinoma 50% (4/8) for adenocarcinoma 33% (1/3) for large cell carcinoma and 100% (1/1) for small cell carcinoma. No CR was obtained in this series. Main side effects due to Cisplatinum were nausea, vomiting, loss of appetite, mild leukopenia and thrombocytopenia, mild elevation of serum creatinine and BUN and alopecia, all of which were transient. Interstitial pneumonitis was observed in 40% of patients with squamous cell cancer. Two patients with adenocarcinoma died within 3 weeks after treatment due to embolism of the abdominal aorta and myocardial infarction probably caused by treatment with Adriamycin.