Detection of human coronavirus RNA in surgical smoke generated by surgical devices

BACKGROUND

Gaseous by-products generated by surgical devices - collectively referred to as 'surgical smoke' - present the hazard of transmitting infective viruses from patients to surgical teams. However, insufficient evidence exists to evaluate and mitigate the risks of SARS-CoV-2 transmission via surgical smoke.

AIM

To demonstrate the existence and infectivity of human coronavirus RNA in surgical smoke using a model experiment and to evaluate the possibility of lowering transmission risk by filtration through a surgical mask.

METHODS

Pelleted HeLa-ACE2-TMPRSS2 cells infected with human coronavirus were incised by electric scalpel and ultrasonic scalpel, separately. A vacuum system was used to obtain surgical smoke in the form of hydrosol. Reverse transcription-quantitative polymerase chain reaction was used to analyse samples for the presence of viral RNA, and infectivity was determined through plaque assay. Furthermore, a surgical mask was placed centrally in the vacuum line to evaluate its ability to filter viral RNA present in the surgical smoke.

FINDINGS

In this model, 1/10⁶ to 1/10⁵ of the viral RNA contained in the incision target was detected in the collected surgical smoke. The virus present in the smoke was unable to induce plaque formation in cultured cells. In addition, filtration of surgical smoke through a surgical mask effectively reduced the amount of viral RNA by at least 99.80%.

CONCLUSION

This study demonstrated that surgical smoke may carry human coronavirus, though viral infectivity was considerably reduced. In clinical settings, surgical mask filtration should provide sufficient additional protection against potential coronavirus, including SARS-CoV-2, infection facilitated by surgical smoke.

Abstract P5-07-07: The immune microenvironment of ductal carcinoma in situ of the breast

Background: The importance of tumor-infiltrating lymphocytes (TIL) in invasive breast carcinoma for tumor development and therapeutic response is widely accepted. However, the immune microenvironment of breast ductal carcinoma in situ (DCIS) has not been fully elucidated. Evasion of immune surveillance is a necessary step in tumor evolution. In DCIS, the tumor cells are relatively protected from the immune system due to an myoepithelial cell layer and basement membrane, and intraductal immune cells are rarely detected. In contrast, in invasive disease, cancer cells and immune cells are often intermingled. Thus, understanding the immune microenviroment of in situ to invasive carcinoma transition might be particularly important to identify novel targets for early stage of tumor invasion.

Aims: The aim of this study is to evaluate the clinical importance of TILs in DCIS.

Methods: TILs were assessed in 133 DCIS samples with or without microinvasive disease according to the proposed method from the International Immuno-Oncology Working Group on Breast Cancer. In addition, the relationship between TILs in DCIS and clinicopathological features was evaluated.

Results: TILs are present in most DCIS in varying levels. The median proportion of TILs in DCIS was 14%. Only a minority of DCIS showed >50% TILs, which represented only 12.8% of all cases. High TILs in DCIS was significantly associated with comedo necrosis (p<0.0001), high nuclear grade (p=0.0030), ER negativity (p<0.0001), PR negativity (p<0.0001), HER2 positivity (p=0.0030). Triple negative DCIS and HER2 positive DCIS had significantly higher level of TILs (p=0.0008). No correlation was demonstrated between TILs and recurrence risk.

Conclusions: High TILs in DCIS was significantly associated with adverse histopathologic features. Further characterization of immune environment of DCIS may be essential for immunotherapy and breast cancer prevention.

Citation Format: Yamashita N, Hisamatsu Y, Shigechi T, Tokunaga E, Saeki H, Oki E, Maehara Y. The immune microenvironment of ductal carcinoma in situ of the breast [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-07-07.

A phase I study of binimetinib (MEK162) in Japanese patients with advanced solid tumors

PURPOSE

Binimetinib is a potent, selective MEK1/2 inhibitor with demonstrated efficacy against BRAF- and RAS-mutant tumors. Retinal adverse events associated with MEK inhibitors have been reported in some cases. The aim of this study was to assess single-agent binimetinib, with detailed ophthalmologic monitoring, in Japanese patients with advanced solid tumors.

METHODS

This was an open-label phase I dose-escalation and dose-expansion study (NCT01469130). Adult patients with histologically confirmed, evaluable, advanced solid tumors were enrolled and treated with binimetinib 30 or 45 mg twice daily (BID). The primary objective was to determine the maximum tolerated dose (MTD) and/or recommended phase II dose (RP2D) of single-agent binimetinib in Japanese patients.

RESULTS

Twenty-one patients were enrolled; 3 and 8 patients had documented BRAF and KRAS mutations, respectively. Two of 6 patients (33 %) receiving binimetinib 45 mg BID in dose-escalation experienced recurrent grade 2 retinal adverse events (AEs) which were reversible, and this dose was declared the MTD and RP2D. All patients experienced ≥1 AE suspected to be treatment related; the most common (>50 %) were blood creatine phosphokinase increase (76 %), retinal detachment and aspartate aminotransferase increase (62 % each), and diarrhea (52 %). There were no complete or partial responses; 14 patients (67 %) had stable disease, which lasted >180 days in 5 patients. Expression of phospho-ERK decreased in the skin following binimetinib treatment at both dose levels, indicating target inhibition.

CONCLUSIONS

Binimetinib demonstrated efficacy and acceptable safety in Japanese patients with solid tumors, supporting the 45 mg BID dose of binimetinib as the RP2D.

New constraint on the existence of the μ+ → e+ γ decay

The analysis of a combined data set, totaling 3.6 × 10(14) stopped muons on target, in the search for the lepton flavor violating decay μ(+) → e(+)γ is presented. The data collected by the MEG experiment at the Paul Scherrer Institut show no excess of events compared to background expectations and yield a new upper limit on the branching ratio of this decay of 5.7 × 10(-13) (90% confidence level). This represents a four times more stringent limit than the previous world best limit set by MEG.

P1-02-10: Vimentin Expression; as a Prognostic Factor and a Possible Molecular Target of Triple Negative Breast Cancer

BACKGROUND: Triple negative breast cancer (TNBC), characterized by absence of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2), is typically associated with aggressive tumor phenotype and poor prognosis. TNBC is also considered highly heterogeneous disease. Since TNBC lacks efficient therapeutic target, it is generally treated with nonspecific cytotoxic agents. A better understanding of molecular and histopathological features of TNBC is of great importance, in order to develop a new therapeutic strategy and to improve the prognosis of TNBC. TNBC has many similarities with basal-like breast cancer (BLBC), and is also associated with stemness and BRCAness. In addition, recent studies suggest links between TNBC and epithelial-mesenchymal transition (EMT). To identify prognostic biomarkers and novel therapeutic targets, we investigated the expression of the factors associated with EMT in TNBC.

MATERIALS and METHODS: Sporadic invasive breast cancer specimens were obtained from 659 Japanese patients who underwent surgery in our department between 1994 and 2010, and 90(14%) cases were diagnosed as TNBC. The E-cadherin and vimentin mRNA expression was evaluated by quantitative RT-PCR. The E-cadherin, vimentin, CK5/6 and epidermal growth factor receptor(EGFR) protein expression was assessed by immunohistochemistry. In this study, we defined TNBC with positive expression of CK5/6 and/or EGFR as BLBC, and TNBC with low expression of E-cadherin and positive expression of vimentin as EMT-type.

RESULTS: Compared with non-TNBC cases, E-cadherin mRNA expression was significantly lower in TNBC cases (p=0.0012). Immunohistochemically, E-cadherin expression was significantly lower (p=0.0001) and vimentin expression was significantly higher (p=0.0049) in TNBC cases. Vimentin expression was associated with younger age (<50 years old, p=0.021), high nuclear grade (p=0.017) and high Ki67 expression (p<.001) in TNBC. Among the patients with TNBC, vimentin expression was significantly associated with poor prognosis, in terms of disease free survival (p=0.0059) and overall survival (p=0.013). Multivariate analysis showed that vimentin expression was an independent prognostic factor for both disease free survival (p=0.017) and overall survival (p=0.012). Among TNBC cases, 52(63%) cases were BLBCs and 15(18%) cases were EMT-type. Among BLBC patients, vimentin expression was also associated with significantly shorter disease free survival (p=0.0085) and overall survival (p=0.0057). The patients with both BLBC and EMT-type features showed especially poor prognosis(P=0.05). CONCLUSION: These findings suggest that elevated expression of vimentin attributes to the aggressive phenotype in TNBC patients. Vimentin expression might be useful as a molecular marker for prognosis of TNBC, and vimentin may represent a novel therapeutic target of TNBC.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-02-10.

New limit on the lepton-flavor-violating decay μ+→e+γ

We present a new result based on an analysis of the data collected by the MEG detector at the Paul Scherrer Institut in 2009 and 2010, in search of the lepton-flavor-violating decay μ(+)e(+)γ. The likelihood analysis of the combined data sample, which corresponds to a total of 1.8×10(14) muon decays, gives a 90% C.L. upper limit of 2.4×10(-12) on the branching ratio of the μ(+)→e(+)γ decay, constituting the most stringent limit on the existence of this decay to date.

The detection of IgG and IgA autoantibodies to desmocollins 1-3 by enzyme-linked immunosorbent assays using baculovirus-expressed proteins, in atypical pemphigus but not in typical pemphigus

BACKGROUND

We have shown previously that human desmocollin (Dsc) 1 is recognized by IgA autoantibodies of subcorneal pustular dermatosis (SPD) type IgA pemphigus. However, the presence of IgG anti-Dsc autoantibodies is still controversial, and antibodies to Dsc2 and Dsc3 have not been clearly identified.

OBJECTIVES

To investigate this by producing recombinant proteins consisting of the entire extracellular domains of human Dsc1, 2 and 3 in baculovirus, and to use them to establish an enzyme-linked immunosorbent assay (ELISA).

METHODS

By this ELISA, we examined in total 165 cases of various types of autoimmune bullous diseases, as well as 23 normal controls.

RESULTS

None of 45 sera of classical pemphigus showed either IgG or IgA antibodies to any Dsc. In contrast, one atypical pemphigus serum showed both IgG and IgA antibodies to Dsc1, which were adsorbed by incubation with Dsc1 baculoprotein. Furthermore, this ELISA detected both IgA and IgG anti-Dsc3 antibodies in one atypical case, and IgA antibodies to both Dsc2 and Dsc3 in another. This reactivity was confirmed by positive IgA immunofluorescence with Dsc2 and Dsc3 expressed on COS-7 cells. These results show that both IgG and IgA autoantibodies against all of Dsc1-3 are present in the sera of particular cases of nonclassical pemphigus, except for IgG antibodies to Dsc2, but that they are not detected in classical pemphigus. Unexpectedly, although IgA antibodies of all of eight SPD type IgA pemphigus sera reacted with Dsc1 expressed on COS-7 cells, only one serum was positive in Dsc1 ELISA for IgA.

CONCLUSIONS

This result indicates either that Dscs expressed by baculovirus may not adopt the correct conformation or that Dscs may need association with other molecules to express all the epitopes for autoantibodies.

Epidermolysis bullosa acquisita sera react with distinct epitopes on the NC1 and NC2 domains of type VII collagen: study using immunoblotting of domain-specific recombinant proteins and postembedding immunoelectron microscopy

BACKGROUND

The sera of epidermolysis bullosa acquisita (EBA) react with type VII collagen, a major component of anchoring fibrils, in which the major epitopes have been considered to be present in the N-terminal noncollagenous (NC) 1 domain.

OBJECTIVES

To determine whether there are also epitopes in the C-terminal NC2 domain, and to determine their ultrastructural localization.

METHODS

Immunoblotting using recombinant proteins of the NC1 and NC2 domains of type VII collagen, and postembedding immunoelectron microscopy.

RESULTS

Twenty of 28 EBA sera tested reacted with the NC1 domain and eight sera reacted with the NC2 domain. The sera that reacted with the NC1 domain showed immunoreactivity within the lamina densa and the sera that reacted with the NC2 domain showed immunoreactivity in the dermis 300-360 nm below the lamina densa.

CONCLUSIONS

This study clearly identified the presence of epitopes in the NC2 domain, and showed that the epitope in the NC1 domain is present in the lamina densa and that the epitope in the NC2 domain is in the dermis below the lamina densa.

Calcium handling and sarcoplasmic-reticular protein functions during heart-failure transition in ventricular myocardium from rats with hypertension

The objective of this study was to determine the primary event that occurs in Ca2+-regulatory sarcoplasmic-reticular (SR) proteins during subacute transition from concentric/mechanically-compensated left ventricular (LV) hypertrophy to eccentric/decompensated hypertrophy. Using Dahl salt-sensitive rats with hypertension, changes of myocardial contraction, intracellular Ca2+ transients, SR Ca2+ uptake, protein levels of SR Ca2+ ATPase (SERCA2), phospholamban, and calsequestrin (CSQ), and mRNA levels of SERCA2 and CSQ were serially determined and compared between the established stage of LV hypertrophy (LVH) and the subsequent stage of overt LV dysfunction (CHF). In LVH, isolated LV papillary muscle preparations showed an equal peak-tension level and a mild prolongation of the isometric tension decay compared to those of age-matched controls. The Ca2+ transients as measured by aequorin were unchanged. The Ca2+ uptake of isolated SR vesicles and the protein/mRNA levels of SR proteins were also equivalent to those of the controls. In contrast, in CHF, the failing myocardium showed a further prolongation of the contraction time course and a 39% reduction of the peak-tension development. The Ca2+ transients showed changes consisting of a decrease in the peak level and a prolongation of the time course. In addition, the SR Ca2+ uptake was decreased by 41%. Despite these functional changes, the protein and mRNA levels of the SR components remained equivalent to those of the age-matched controls. Thus, in this hypertensive animal, 1) at the LVH stage, myocardial contractility and intracellular capability to regulate Ca2+ remained normal; 2) at the CHF stage, impaired SR Ca2+ handling and the subsequent reduction of myocardial contraction were in progress; and 3) impairments of SR function occurred at the post-translational protein level rather than at the transcriptional/translational levels. Our findings support the role of SR proteins as the primary determinant of the contractile dysfunction that occurs during the heart-failure transition; however, post-translational modulators of these SR elements may also be critical.

Environmental occurrence of nitrotriphenylene observed in airborne particulate matter

1- and 2-Nitrotriphenylenes were found in the airborne particulate matter extracts collected in central Tokyo between the winter of 1998 and the winter of 1999. In particular, we have identified and quantified nitrotriphenylenes in the airborne particulate matter extracts collected over four consecutive 6-h periods on 2 December 1999. The concentrations of 1- and 2-nitrotriphenylene ranged from 0.04 to 0.44 and from 0.02 to 0.47 ng/m3, respectively, and the concentrations in the airborne particulate matter extracts collected during the 18:00-24:00 h time period were the highest of the four collection periods. 1-Nitropyrene and 2-nitrofluoranthene were also identified and quantified in the four 6-h samples. Although the concentrations of 1- and 2-nitrotriphenylenes were not higher than that of 2-nitrofluoranthene except during the 18:00-24:00 h time period, the concentrations were much higher than that of 1-nitropyrene during the four collection periods. The higher concentrations of 1- and 2-nitrotriphenylenes during the 18:00-24:00 h time period are presumably responsible for the high reactivity of parent triphenylene with NO2/NO3/N2O5, and high stability of 1- and 2-nitrotriphenylenes toward O3 + O2. In addition, the observed isomer distribution of nitrotriphenylenes suggested that direct emission of nitrotriphenylenes is also a source as well as their atmospheric formation.

Mutagenic nitrated benzo[a]pyrene derivatives in the reaction product of benzo[a]pyrene in NO2-air in the presence of O3 or under photoirradiation

In order to clarify the contribution of nitrated products to the direct-mutagenic activity of products of the reactions of benzo[a]pyrene in NO2-air under various conditions, heterogeneous reactions of BaP deposited on filter in the air containing 10 ppm of NO2 have been conducted in dark or under photoirradiation. The reaction products have been analyzed by gas chromatography and mutagenicity of the products fractionated by preparative HPLC was assayed for Salmonella typhimurium strains TA98 and YG1024 in the absence of S9 mix. 3,6-dinitrobenzo[a]pyrene and 1,3-dinitrobenzo[a]pyrene, which are strong direct-acting mutagens, largely contributed to the total direct-acting mutagenicity of the dark reaction products in NO2-air. On the other hand, both the dark reaction in the presence of O3 and the photoreaction in NO2-air resulted in the formation of much smaller amounts of nitrobenzo[a]pyrenes than that observed in the dark reaction in the absence of O3. These results show that the contribution of other direct-acting mutagens to the total direct-acting mutagenicity of the products in these reactions should be considered. Benzo[a]pyrene lactones were identified in a highly mutagenic fraction of the products of the dark reaction in the presence of O3 and photoreaction and a nitrobenzo[a]pyrene lactone was also identified in a highly mutagenic fraction of the dark reaction products in the presence of O3. Nitrated oxygenated benzo[a]pyrene derivatives such as nitrobenzo[a]pyrene lactone were considered to largely contribute to direct-acting mutagenicity of the products of the dark reaction in the presence of O3 and photoreaction.

Altered stoichiometry of FKBP12.6 versus ryanodine receptor as a cause of abnormal Ca(2+) leak through ryanodine receptor in heart failure

BACKGROUND

In the pathogenesis of cardiac dysfunction in heart failure, a decrease in the activity of the sarcoplasmic reticulum (SR) Ca(2+)-ATPase is believed to be a major determinant. Here, we report a novel mechanism of cardiac dysfunction revealed by assessing the functional interaction of FK506-binding protein (FKBP12.6) with the cardiac ryanodine receptor (RyR) in a canine model of pacing-induced heart failure.

METHODS AND RESULTS

SR vesicles were isolated from left ventricular muscles (normal and heart failure). The stoichiometry of FKBP12.6 per RyR was significantly decreased in failing SR, as assessed by the ratio of the B(max) values for [(3)H]dihydro-FK506 to those for [(3)H]ryanodine binding. In normal SR, the molar ratio was 3.6 ( approximately 1 FKBP12.6 for each RyR monomer), whereas it was 1.6 in failing SR. In normal SR, FK506 caused a dose-dependent Ca(2+) leak that showed a close parallelism with the conformational change in RyR. In failing SR, a prominent Ca(2+) leak was observed even in the absence of FK506, and FK506 produced little or no further increase in Ca(2+) leak and only a slight conformational change in RyR. The level of protein expression of FKBP12.6 was indeed found to be significantly decreased in failing SR.

CONCLUSIONS

An abnormal Ca(2+) leak through the RyR is present in heart failure, and this leak is presumably caused by a partial loss of RyR-bound FKBP12.6 and the resultant conformational change in RyR. This abnormal Ca(2+) leak might possibly cause Ca(2+) overload and consequent diastolic dysfunction, as well as systolic dysfunction.

PKA phosphorylation dissociates FKBP12.6 from the calcium release channel (ryanodine receptor): defective regulation in failing hearts

The ryanodine receptor (RyR)/calcium release channel on the sarcoplasmic reticulum (SR) is the major source of calcium (Ca2+) required for cardiac muscle excitation-contraction (EC) coupling. The channel is a tetramer comprised of four type 2 RyR polypeptides (RyR2) and four FK506 binding proteins (FKBP12.6). We show that protein kinase A (PKA) phosphorylation of RyR2 dissociates FKBP12.6 and regulates the channel open probability (Po). Using cosedimentation and coimmunoprecipitation we have defined a macromolecular complex comprised of RyR2, FKBP12.6, PKA, the protein phosphatases PP1 and PP2A, and an anchoring protein, mAKAP. In failing human hearts, RyR2 is PKA hyperphosphorylated, resulting in defective channel function due to increased sensitivity to Ca2+-induced activation.

Mechanism of preserved positive lusitropy by cAMP-dependent drugs in heart failure

In tachycardia-induced heart failure (HF), positive lusitropic effects of milrinone or dobutamine were assessed by evaluating the time constant of left ventricular (LV) pressure decay (tau) and Ca(2+)-ATPase activity of the sarcoplasmic reticulum (SR). The peak value of the positive first derivative of LV pressure (+dP/dt) was less increased, either by dobutamine (2-10 microg x kg(-1) x min(-1)) or by milrinone (4-20 microg/kg), in HF than in control (P < 0.05), whereas tau was shortened to an extent similar to that in control with dobutamine [P = not significant (NS)] and to an even greater extent with milrinone (P < 0.05). Ca(2+)-ATPase activity increased similarly in HF and control with dobutamine (1 microM; +11% in HF vs. +12% in control, P = NS), whereas it increased more with milrinone (1 microM; +19% in HF vs. +11% in control, P < 0.05). Ca(2+)-ATPase activity-cAMP relationships were shifted to the left by milrinone or dobutamine in HF compared with control. Thus, in HF, the sensitivity of Ca(2+)-ATPase activity to cAMP was increased on addition of cAMP-dependent inotropic agents, contributing to the preservation of positive lusitropy.

[A clinical investigation of infective endocarditis at a community hospital in Japan]

There have been few reports on the clinical features of infective endocarditis (IE) in Japan. We clinically investigates 45 episodes (36 cases) of definite IE that were experienced from January 1985 to March 1997 at a community hospital, Okinawa Chubu Hospital, Okinawa, Japan. Regarding age, prior dental procedure, causative organisms and sites of infection, analyses and comparison were performed on a total of 94 episodes, by adding another 49 episodes of IE that were experienced between 1977 and 1984 at our hospital. The mean age was 47 years and majority of patients in the recent 12 years were older than 50 years of age. Mortality of all 94 episodes was 20%, while that of recent 45 cases was 13%. Eight % of all episodes had history of recent dental treatment but significance of the finding remains unclear. Alpha streptococci were most common (33%) and Staphylococcus aureus was the second most common organism (17%). Eleven % of all episodes were culture-negative and there was a statistically significant difference in the histories of prior antibiotic therapy between culture-negative and culture-positive episodes. Regarding sites of infection, 27% of all episodes involved mitral valves, while 24% involved aortic valves. Prosthetic valves were involved in 12%. Ninety-eight % of the recent episodes had fever, 98% had cardiac murmurs and 27% had characteristic mucocutaneous lesions. Heart failure was the most common complication (27%) and half of the cases with prosthetic valve infection had heart failure. Cerebral embolism was most frequently seen among the major arterial embolic complications. Our results were similar to those which were previously reported from other countries. We should have a high index of suspicion for endocarditis whenever we see patients who present various clinical manifestations and fever of which origin remains unclear. Willingness to obtain blood culture before starting antibiotics is most important.

Abnormal Ca2+ release from cardiac sarcoplasmic reticulum in tachycardia-induced heart failure

OBJECTIVE

In heart failure, little information is available as to the Ca2+ release function of sarcoplasmic reticulum (SR), which plays a major role in cardiac contractile function. Here, we assessed the rapid kinetics of drug-induced Ca2+ release from cardiac SR in combination with a measurement of ryanodine binding in heart failure.

METHODS

The SR vesicles were isolated from dog left ventricular (LV) muscles (normal (N), n = 10; pacing induced heart failure (HF), n = 10). The time course of SR Ca2+ release was continuously monitored by a stopped-flow apparatus using arsenazoIII as a Ca2+ indicator, and Ca2+ uptake and [3H]ryanodine binding assays were done using a filtration method.

RESULTS

The amount of Ca2+ uptake was reduced in HF to 55% of N (P < 0.05). Even the more marked and earlier appeared decrease was seen in the rate constant and the initial rate of polylysine (PL; a specific release trigger)-induced Ca2+ release (P < 0.05). However, the PL concentration dependency of the initial rate shifted towards lower concentrations of PL in HF than in N ([PL] at half maximum stimulation = 0.13 vs. 0.35 microM). The [3H]ryanodine binding assay revealed a lower Bmax (pmol/mg) in HF than in N (0.91 +/- 0.19 vs. 2.64 +/- 0.59, P < 0.05), but no difference in Kd (nM) (0.95 +/- 0.29 vs. 0.90 +/- 0.11, P = n.s.). The [PL] dependency on the enhancement of [3H]ryanodine binding again showed a shift towards lower [PL] in HF than in N.

CONCLUSIONS

In pacing-induced heart failure, the Ca2+ releasing function of SR is disturbed, which may result in an intra-cellular Ca2+ transient that was slowed down.

An unusual DNA adduct derived from the powerfully mutagenic environmental contaminant 3-nitrobenzanthrone

The covalent binding of an N-hydroxy metabolite of the powerfully mutagenic 3-nitrobenzanthrone (NBA) to 2'-deoxyguanosine (dG) and calf thymus DNA has been investigated in vitro. The major adduct obtained from the reaction of the N-acetoxy-N-acetyl derivative (N-Aco-N-Ac-ABA) of 3-aminobenzanthrone (ABA) and dG was identified as N-acetyl-3-amino-2-(2'-deoxyguanosin-8-yl)benzanthrone (dG-N-Ac-ABA) by 1H NMR and mass spectroscopies as well as by the reaction of N-Aco-N-Ac-ABA with the double-stranded calf thymus DNA. The coupling with the dG moiety occurred exclusively at C-2 of benzanthrone (BA), suggesting a significant contribution of a resonance-stabilized arenium ion intermediate derived from BA to the production of this new type of adduct. The preferred conformation of the adduct has been shown to be syn by 1H and 13C NMR.

Importance of left anterior descending coronary artery curvature in determining cross-sectional plaque distribution assessed by intravascular ultrasound

We assessed the relation between the circumferential distribution of coronary atherosclerotic plaques and the structure of the epicardial coronary arteries in patients with coronary artery disease using intravascular ultrasound in vivo. Coronary atherosclerosis preferentially formed at the inner arc of the curved coronary vessels, and greater vessel curvatures were associated with greater distributions of atherosclerotic lesions along the inner coronary artery wall.

Effects of dantrolene sodium on progression of left ventricular hypertrophy induced by pressure overload in rats

We studied the long-term effects of dantrolene sodium (D), a specific sarcoplasmic reticulum (SR) Ca2+-release inhibitor, on the progression of left ventricular pressure-overloaded hypertrophy in rats. We treated abdominal aorta-constricted rats with one of two doses of D for 4 weeks. The extent of hypertrophy was expressed as the ratio of left ventricle to body weight. Hemodynamic parameters were measured by using a microtip catheter manometer. Although a low dose of D (500 mg/L in drinking water) decreased blood pressure to normal levels, the progression of cardiac hypertrophy was not inhibited. In contrast, a high dose of D (5 mg/kg, i.p.) also reduced blood pressure and inhibited the progression of cardiac hypertrophy. Dantrolene sodium had no effect on cardiac function in sham-operated rats. Thus control of Ca2+ release from the SR might be crucial in regulating the progression of cardiac hypertrophy, the final mediator possibly being intracellular Ca2+ concentration.

Alterations in cardiac SR Ca(2+)-release channels during development of heart failure in cardiomyopathic hamsters

The cardiomyopathic Syrian hamster develops a progressive cardiomyopathy characterized by cellular necrosis, hypertrophy, cardiac dilatation, and congestive heart failure. This study aimed to identify alterations in cardiac mechanical function and in the cellular content of sarcoplasmic reticulum (SR) Ca(2+)-release channels (ryanodine receptors, RyR) in the heart of the UM-X7.1 cardiomyopathic hamster during the development of heart failure. Experimental and healthy control hamsters were examined at 8, 18, and 28 wk of age. The UM-X7.1 hamsters had developed left ventricular (LV) hypertrophy at 8 wk and a marked LV dilatation at 18-28 wk. During the latter stage, the UM-X7.1 hamster hearts showed global hypokinesis. Equilibrium binding assays of high-affinity sites for [3H]ryanodine were performed in ventricular homogenate preparations. There was no significant difference between the two groups in the maximum number of [3H]ryanodine binding sites (Bmax) at either 8 or 18 wk of age, although the cardiac pump function was impaired in UM-X7.1 hamsters at 18 wk of age. By 28 wk, Bmax was significantly lower in the UM-X7.1 hamsters. Quantitative immunoblot assay revealed that the content of RyR protein in cardiomyopathic hearts, which was increased at the early stage, declined to below normal as heart failure advanced. These results suggest that the number of RyR in the UM-X7.1 cardiomyopathic hamsters was preserved at both the hypertrophic and early stages of heart failure with a possibly compensatory increase in the level of protein expression, although the cardiac function already showed a tendency to be impaired.

Early changes in the functions of cardiac sarcoplasmic reticulum in volume-overloaded cardiac hypertrophy in rats

By sequestering activator calcium, the sarcoplasmic reticulum (SR) plays the central role in the excitation-contraction (E-C) cycle of cardiac muscle. Hence, functional changes in the SR in diseased myocardium might critically determine its mechanical characteristics. Previously, we demonstrated that both Ca2+ release and uptake were increased in SR isolated from hearts showing compensatory left ventricular (LV) hypertrophy taken from pressure-overloaded rats. However, it has not been elucidated whether such alterations also occur in the volume-overloaded myocardium. Rats in which volume-overloaded hypertrophy had been induced by aortocaval shunt 12 weeks prior to the investigation were compared to sham-operated controls in terms of SR Ca2+ uptake and release, and density of Ca2+ releasing channels (ryanodine receptors, RyR). Isometric tension and intracellular Ca2+ transients were also measured using the bioluminescent Ca2+ indicator, aequorin, in isolated LV papillary muscles. The extent of hypertrophy was verified by measuring the ratio of biventricular weight to body weight. In vivo, the aortocaval shunt rats showed normal LV contractility and slightly depressed LV relaxation, indicating a compensatory (adaptive) stage of LV function. In contrast, Ca2+ release, uptake, and maximal number of [3H]-ryanodine binding sites were all significantly lower in aortocaval shunt rats than in controls. Both the Ca2+ transients and isometric relaxation of the isolated myocardium were significantly prolonged in aortocaval shunt rats, though their amplitudes were similar in the two groups. Thus, the volume-overloaded cardiac hypertrophy, even at its hemodynamically compensatory (adaptive) stage, (i) was accompanied by abnormal Ca2+ handling, as indicated by prolonged intracellular Ca2+ transients and isometric tension traces, (ii) seems to involve subcellular mechanisms related to decreases in SR Ca2+ release and uptake functions, as well as to a decrease in the number of RyR. Therefore, changes in the intracellular processes underlying cardiac E-C coupling, including SR function, precede the development of this type of heart disease.

Differences in sarcoplasmic reticulum gene expression in myocardium from patients undergoing cardiac surgery. Quantification of steady-state levels of messenger RNA using the reverse transcription-polymerase chain reaction

Little is known about any alterations in sarcoplasmic reticulum (SR) gene expression associated with cardiac diseases of varying degrees of severity. We assessed, using the reverse transcription-polymerase chain reaction (RT-PCR) technique, SR Ca2+ transport protein gene expression in small tissue samples from failing hearts in patients undergoing cardiac surgery. Total RNA was extracted from 30- to 50-mg samples from the hearts of 13 patients with coronary artery disease, congenital heart disease, or valvular heart disease. We used RT-PCR to synthesize and amplify cDNA encoding cardiac SR Ca(2+)-ATPase, ryanodine receptor (RYR), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The amount of each mRNA in the sample was expressed relative to the amount of GAPDH mRNA. The expression level of each mRNA was correlated with the cardiac functional index. The mRNA levels for Ca(2+)-ATPase and RYR varied between heart samples, but showed a positive correlation with left ventricular ejection fraction. Ca(2+)-ATPase mRNA levels showed in inverse relationship with plasma brain natriuretic peptide. In addition, we isolated partial cDNA encoding a human cardiac RYR. The cDNA consisted of 487 nucleotides, and the nucleotide and deduced amino acid sequences showed 93% and 99% homology, respectively, to those of rabbit cardiac RYR. These results suggest that decreased levels of mRNA for SR Ca2+ transport protein could be related to abnormal cardiac function, regardless of the etiology of the heart disease. RT-PCR provides a rapid and economical way of quantifying the expression of multiple genes in small specimens and may, therefore, aid understanding of the pathophysiology and treatment of heart disease.

Altered cardiac mechanism and sarcoplasmic reticulum function in pressure overload-induced cardiac hypertrophy in rats

Cardiac sarcoplasmic reticulum (SR) sequesters Ca2+ and plays a crucial role in the regulation of intracellular Ca2+. Its functional properties are central to the excitation-contraction (E-C) cycle of cardiac muscle. In this study, we examined the hypothesis that alterations in SR function occur during the development of hypertrophy of the left ventricle (LV) induced in rats by pressure overload secondary to abdominal aortic coarctation. Ten days, 4 and 8 weeks after the operation, hemodynamic parameters were measured using a catheter-tip manometer. The SR vesicles of hypertrophic LV (group A) and sham-operated LV (group S) at each stage were used to study Ca2+ release and uptake, and to characterize the ryanodine receptor. Moderate hypertrophy was observed in group A even at the earliest stage. Systolic LV pressure and peak +dP/dt were significantly increased in group A. There were no significant change in diastolic LV pressure in either group at any stage. Hemodynamic data indicated that LV function in group A was enhanced during the development of the hypertrophy. The amount of Ca2+ release and uptake, and the number of ryanodine binding sites on the SR were higher in group A than in group S at both early and middle stages. However, 8 weeks after the operation, SR activity was normal, even though cardiac function was still augmented. Our results indicated that LV hypertrophy induced by pressure overload is associated with altered intracellular Ca2+ regulation, as reflected by the increased Ca2+ release and uptake functions of the SR and the quantitative change in the number of ryanodine receptors during the early stages of the development of hypertrophy. Therefore, alterations in the SR Ca2+ transport capacity could account, at least in part, for the alterations in E-C coupling seen in hypertrophy.

Influence of aortic impedance on the development of pressure-overload left ventricular hypertrophy in rats

BACKGROUND

Aortic input impedance, which represents LV afterload, is considered to be a major determinant for the development of pressure-overload left ventricular (LV) hypertrophy.

METHODS AND RESULTS

To test whether the sustained change in aortic input impedance might affect the mode of development of LV hypertrophy, coarctation of either the ascending aorta (G1, n = 13) or suprarenal abdominal aorta (G2, n = 12) was performed over 4 weeks in 6-weeks-old Wistar rats. Although peak LV pressure and total systemic resistance were increased similarly in G1 and G2, time to peak LV pressure was decreased by 24% (P < .01) in G1 compared with G2. The aortic input impedance spectra revealed that the early systolic loading in G1 was characterized by an increase in characteristic impedance, whereas the late systolic loading in G2 was by an augmented arterial wave reflection. G1 showed a smaller increase (P < .01) in either the ratio of LV weight (mg) to body weight (g) or LV wall thickness than G2 after aortic banding. Myocyte diameter was also smaller (P < .05) in G1 (14.3 +/- 0.7 mm) than in G2 (16.1 +/- 1.2 mm). The ex vivo passive pressure-volume relation had a rightward shift in G1 compared with G2, suggesting less concentric LV hypertrophy in G1.

CONCLUSIONS

The sustained early systolic loading due to the increase in characteristic impedance was accompanied by less concentric, reduced hypertrophy, whereas the sustained late systolic loading due to the augmented arterial wave reflection was accompanied by concentric, adequate hypertrophy.

[Acute massive pulmonary embolism--report of a case]

A 72-year-old female, who had received medication for hypertension and angina pectoris was hospitalized with complaining of an abrupt dyspnea. Roentgenogram of the chest revealed no abnormal findings except cardiac enlargement. An electrocardiogram showed overloading of the right ventricle. Arterial blood gas analysis of room air showed 55.4 mmHg of PaO2, 25.5 mmHg of PaCO2 and 7.30 of PH, respectively. Acute and massive pulmonary embolism was diagnosed by an emergent pulmonary arteriography. Despite intensive treatment such as infusion of urokinase and heparin for four days, thrombus was still detected in the left main pulmonary artery by a transesophageal echocardiography. By the result of ineffective conservative therapy, embolectomy was performed under cardiopulmonary bypass. However mechanical respiratory support was required for a long time due to the right heart failure, she is doing well for a year after the operation.

Mutagenicity of the reaction products of carbazole in the presence of nitrogen dioxide and nitrocarbazole

The mutagenicity of the photochemical reaction products of carbazole in the presence of nitrogen dioxide (NO2) and nitrocarbazole was investigated using a high-pressure mercury lamp (100 W). Samples extracted from the photochemical reaction products of carbazole with NO2 were more mutagenic than those of acridine and phenazine with NO2 for Salmonella typhimurium strain TA98 in the absence of S9 mix with a trend toward detoxification in the presence of the metabolic system. The mutagenicity of the photochemical reaction products of carbazole with NO2 were higher than those of the reaction products of carbazole with a mixture of NO2 and sulfur dioxide (SO2) and no irradiation. Mononitro- and dinitro-carbazole in the samples extracted from the reaction products were analyzed by mass spectrometry. It was suggested that mononitrocarbazole, which seemed to be weakly mutagenic, and dinitrocarbazole were readily formed by the reaction of carbazole with NO2, and that the other high-potency mutagens were formed by the photochemical reaction of carbazole with NO2 with irradiation by light.

Mutagenicity of the photochemical reaction products of pyrene with nitrogen dioxide

The mutagenicity of the photochemical reaction products of pyrene with nitrogen dioxide (NO2) and the mutagens in them were investigated for the interpretation of their biological significance as genetoxic hazards of polycyclic aromatic hydrocarbons (PAHs) in airborne particles. Samples extracted from the photochemical reaction products of pyrene with NO2 diluted with air using a high-pressure mercury lamp were mutagenic for Salmonella typhimurium strains TA97 and TA98 in the absence of S9 mix, with a trend to detoxification in the presence of the metabolic system. The mutagens in the crude samples extracted from their products, which were fractionated by normal-phase high-performance liquid chromatography (HPLC) on a column of Nucleosil 100-30 with n-hexane-benzene as an eluting solution, were analyzed by HPLC, mass spectrometry and Fourier transform infrared (FT-IR) spectrometry. Based on these results, it was recognized that 1-nitropyrene (1-NP), 1,3-dinitropyrene (1,3-DNP), 1,6-dinitropyrene (1,6-DNP) and 1,8-dinitropyrene (1,8-DNP) was formed by the photochemical reaction of pyrene with NO2. The yield of DNPs peaked at 2-3 h irradiation.