[Air pollution and heart rhythm disturbance: A retrospective study]

INTRODUCTION

According to many studies, exposure to air pollution increases cardiovascular morbidity and mortality. It has also been shown that the frequency of heart rhythm disorders in Region wallonne is very high.

OBJECTIVES

The objective of this study is to test the hypothesis of a link between rhythm disorders measured by cardiac holters and data from devices measuring the concentration of air pollutants present in ambient air.

METHODOLOGY

The health data were obtained via the Erasme hospital's cardiology center. This is a retrospective data collection over the last 2 to 5 years. The environmental data are: PM2.5, PM10, NO2, O3 and temperature. The statistical models were based on "cross-case" analyses.

RESULTS

An association between PM10 and the number of ESAs was observed. An increase of 10μg/m³ of PM10 increases the number of ESAs by 20% (P=0.040). The number of ESAs increases with age (63% more ESAs when age increases by 10 years). A history of intervention also decreases the number of ESAs (-35%), the same phenomenon is observed for pacemaker wearers (-66%). The strongest association observed between NO2 and ESA with an OR of 1.37 (P=0.027) in the final model. No significant association was observed between the effects of air pollution and VPCs.

CONCLUSION

Our analyses resume the effects of the different pollutants on rhythm disorders, the effects adjusted for treatment and co-morbidities. They open the door to other more refined studies based on individual measurements.

[Analysis of comorbidities in hospitalized patients for ischemic stroke and their effects on lethality]

OBJECTIVES

The aim of the study consists of analyzing the comorbidities of acute ischemic stroke and those influencing its hospital lethality.

METHODS

We considered patients from Wallonia aged 25 years or more and admitted to a Belgian hospital for an acute ischemic stroke in 2013 and 2014. The analyzed medico-administrative data are taken from the Minimum Hospital Summary. A factorial correspondence analysis (FCA) was used to demonstrate the comorbidities profiles. A logistic regression was used to analyse the comorbidities influencing hospital lethality by ischemic stroke.

RESULTS

The stroke risk factors vary according to the age. Cardiac problems are more common in older people aged 85 years or more. High blood pressure, hypercholesterolemia and diabetes are more present between 65- and 84-year-olds. Overweight is more present between 55 and 74-year-olds. People who are addicted to alcohol or tobacco are often 65 years or younger. The logistic regression showed that age and heart problems are the risk factors that increase lethality. However there is a lethality diminution in the presence of high blood pressure, hypercholesterolemia, overweight and addiction to alcohol or tobacco.

CONCLUSION

This study demonstrates that medico-administrative databases and factorial statistical methods are perfectly adapted to confirm the ischemic stroke risk factors. This type of study will allow to target with more precision the secondary and tertiary prevention actions of stroke.

P809Effects of air temperature and pollution on Takotsubo cardiomyopathy

Background

Air temperature and pollution are the main environmental factors influencing cardiovascular mortality and risk of myocardial infarction. Takotsubo cardiomyopathy (TCM) is a transient and reversible myocardial dysfunction whose cause and pathogenesis remain incompletely understood, but which, unlike acute coronary syndrome, does not involve obstructive coronary atherosclerosis or plaque rupture. The potential role of the environment on the risk to develop TCM remains poorly defined.

Methods

We aimed to study the effects of air temperature, particulate matter (PM) and gaseous pollutants (NO2 and ozone) on hospitalization rate forTCM.

All hospitalizations in Belgian Hospitals for TCM (ICD 9:429.83) from 2009 to 2014 were recorded. National air pollution parameters were extracted from the Belgian Environment Agency database. A time-stratified and temperature-matched (except for air temperature effect) case-crossover analysis of the risk of TCM was performed. The main analysis focused on 0-day lag time (lag 0) between exposure and TCM; a lag structure analysis up to lag 4 was also performed.

Results

1840 patients were included in the study (88% women). More TCM occurred during the warm compared to the cold period (fig.1; chi2p value <0.05). At lag 0, each decrease of 1°C in ambient air temperature increased the odds ratio (OR) of TCM of 1.020 (IC 95%: 1.003–1.035). This effect was more pronounced during the cold period and at lag 4 (RR 1.060; IC 95%: 1.031–1.091). Conversely, during the warm period and between lag 1 and 4, an increase of 1°C in ambient air temperature increased the RR of TCM (OR 1.053 at lag 3; IC 95%: 1.021–1.086). No significant association was found between TCM and PM10, PM2.5, NO2at any lag. During the warm period, each increase in 10μg/m3 in ozone from lag 1 to 3 increased the risk of TCM (OR 1.089 at lag 3, IC 95%: 1.017–1.168).

Conclusions

Air temperature strongly influences the onset of TCM. Both cold spells and heat waves seem to be associated with the development of TCM. Ozone exposure also increases the risk of TCM during the warm period, whereas particulate and NO2 pollution do not seem to play a significant role. These patterns seem to differ from those previously reported with STEMI.

Air pollution and ST-elevation myocardial infarction: A case-crossover study of the Belgian STEMI registry 2009-2013

BACKGROUND

Previous studies have shown that air pollution particulate matter (PM) is associated with an increased risk for myocardial infarction. The effects of air pollution on the risk of ST-elevation myocardial infarction (STEMI), in particular the role of gaseous air pollutants such as NO₂ and O₃ and the susceptibility of specific populations, are still under debate.

METHODS

All patients entered in the Belgian prospective STEMI registry between 2009 and 2013 were included. Based on a validated spatial interpolation model from the Belgian Environment Agency, a national index was used to address the background level of air pollution exposure of Belgian population. A time-stratified and temperature-matched case-crossover analysis of the risk of STEMI was performed.

RESULTS

A total of 11,428 STEMI patients were included in the study. Each 10μg/m³ increase in PM10, PM2.5 and NO₂ was associated with an increased odds ratio (ORs) of STEMI of 1.026 (CI _95%: 1.005-1.048), 1.028 (CI _95%: 1.003-1.054) and 1.051 (CI _95%: 1.018-1.084), respectively. No effect of O₃ was found. STEMI was associated with PM10 exposure in patients ≥75y.o. (OR: 1.046, CI _95%: 1.002-1.092) and with NO₂ in patients ≤54y.o. (OR: 1.071, CI _95%: 1.010-1.136). No effect of air pollution on cardiac arrest or in-hospital STEMI mortality was found.

CONCLUSION

PM2.5 and NO₂ exposures incrementally increase the risk of STEMI. The risk related to PM appears to be greater in the elderly, while younger patients appear to be more susceptible to NO₂ exposure.

[Acute myocardial infarction in Charleroi: evolution of risk factors and therapeutic practices]

OBJECTIVES

The aim of the study consists in analyzing the evolution of acute coronary risk factors as well as the 28 days case fatality and the therapeutic practices over 12 years of follow-up in Charleroi. The factors influencing the mortality of these patients are also investigated.

METHODS

The Charleroi register of ischaemic cardiopathies is the oldest register of infarctions in the French-speaking community of Belgium. Analyses presented hereafter relate only patients in the 25-69-year age range over time from 1998 to 2009. Some analysis was extended to 25-74-year range. Treatment and risk factors evolutions over time were analysed using Chi(2) tests. Logistic regression was used to identify factors influencing 28 days mortality.

RESULTS

The analysis shows a significant decline in 28 days mortality. A marked increase in the prevalence of hypertension and hypercholesterolemia is highlighted as well as an increase of utilization of percutaneous transluminal coronary angioplasty (PTCA) between 1998 and 2009. The use of ß-blockers and antiplatelet drugs remained fairly stable between 1998 and 2009 with approximately 75% and 90% of the patients treated, respectively. The factors associated with fatality were specifically age of patients, antecedents of diabetes and antecedents of myocardial infarction, hypercholesterolaemia as well as oral antiplatelet drugs, ß-blockers therapies and PTCA.

CONCLUSIONS

The evolution of the therapeutic data on AMI in this register confirms that PTCA becomes the main coronary reperfusion. Angiotensin-converting enzyme inhibitors were without effect on mortality.

Comparative pharmacokinetics and metabolism of levetiracetam, a new anti-epileptic agent, in mouse, rat, rabbit and dog

1: The pharmacokinetics and metabolism of 14C-levetiracetam, a new anti-epileptic agent, in mouse, rat, rabbit and dog after a single oral dose were investigated. Moreover, the in vitro hydrolysis of levetiracetam to its major carboxylic metabolite by rat tissue homogenates was investigated to identify tissues involved in the production of the metabolite. Data are also presented on the induction of the enzyme(s) involved in levetiracetam hydrolysis in the rat. 2: Levetiracetam was rapidly and almost completely absorbed. The unchanged drug accounted for a very high percentage of plasma radioactivity. Levetiracetam did not bind to plasma proteins. Although brain radioactivity concentrations were lower than those of whole blood at early time points, brain-to-blood ratios increased over time. The predominant route of elimination of total 14C was excretion via urine, accounting for about 81, 93, 87 and 89% of the dose in the mouse, rat, rabbit and dog, respectively. Consequently, levetiracetam was poorly metabolized. It was submitted in vivo to hydrolysis and/or oxidation. Hydrolysis of the amide function of levetiracetam produced the corresponding acid. However, levetiracetam could also be oxidized at positions 3 and 4 of the 2-oxopyrrolidine ring. Finally, the compound and the corresponding acid metabolite could be oxidized at position 5 of the 2-oxopyrrolidine ring and then hydrolysed with the opening of the ring. 3: All the investigated rat tissues (liver, kidney, lung, brain, small intestine mucosa) had the potential to produce the acid metabolite. By contrast, the acid was undetectable following incubation of levetiracetam with buffer alone or heat-denaturated liver fractions. 4: No marked species or sex differences were observed in the absorption, disposition and metabolism of levetiracetam. 5:The hydrolysis of levetiracetam is carried out by an enzymatic process characterized by a broad tissue distribution. In the rat, the enzyme system hydrolysing levetiracetam is not induced by phenobarbital, at least under the experimental conditions used herein, whereas the enzyme system(s) involved in the other metabolic pathways is induced.

Discovery of orally bioavailable NK1 receptor antagonists

Benzyloxyphenethylpiperazines are a new class of high affinity NK1 receptor antagonists. Oral bioavailability and selectivity can be fine tuned by the nature of the substituents on the basic nitrogen atom. Addition of substituents with a carboxylic acid group led to very selective and orally active NK1 antagonists free of interaction with L-type calcium channels.

In vitro inhibition of human liver drug metabolizing enzymes by second generation antihistamines

Cetirizine, terfenadine, loratadine, astemizole and mizolastine were compared for their ability to inhibit marker activities for CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP3A4 and for some glucuronidation isoenzymes in human liver microsomes. The most pronounced effects were observed with terfenadine, astemizole and loratadine which inhibited CYP3A4-mediated testosterone 6beta-hydroxylation (IC50 of 23, 21 and 32 microM, respectively) and CYP2D6-mediated dextromethorphan O-demethylation (IC50 of 18, 36 and 15 microM, respectively). In addition, loratadine markedly inhibited the CYP2C19 marker activity, (S)-mephenytoin 4-hydroxylation (Ki of 0.17 microM). Furthermore, loratadine activated the CYP2C9-catalyzed tolbutamide hydroxylation (ca. 3-fold increase at 30 microM) and inhibited some glucuronidation enzymes. Mizolastine appeared to be a relatively weak and unspecific inhibitor of CYP2E1, CYP2C9, CYP2D6 and CYP3A4 (IC50Ss in the 100 micromolar range). Cetirizine demonstrated no effect on the investigated activities. A comparison of the inhibitory potencies of cetirizine, terfenadine, loratidine, astemizole and mizolastine with their corresponding plasma concentrations in humans suggests that these antihistamines are not likely to interfere with the metabolic clearance of coadministered drugs, with the exception of loratidine, which appears to inhibit CYP2C19 with sufficient potency to warrant additional investigation.

In vitro evaluation of potential drug interactions with levetiracetam, a new antiepileptic agent

Levetiracetam and its carboxylic metabolite (AcL) were tested for their potential inhibitory effect on 11 different drug metabolizing enzyme activities using human liver microsomes. The following specific assays were investigated: testosterone 6beta-hydroxylation [cytochrome P-450 3A4 (CYP3A4)], coumarin hydroxylation (CYP2A6), (R)-warfarin hydroxylation (CYP1A2), (S)-mephenytoin hydroxylation (CYP2C19), p-nitrophenol hydroxylation (CYP2E1) tolbutamide hydroxylation (CYP2C9), dextromethorphan O-demethylation (CYP2D6), epoxide hydrolase and UDP-glucuronyltransferase (UGT) toward paracetamol (UGT1*6), ethinyloestradiol (UGT1*1), p-nitrophenol (UGT(pl 6.2)), and valproic acid. None of these activities were affected by levetiracetam or AcL added at concentrations up to 1 mM. Additionally, primary cultures of rat hepatocytes were used to assess a potential inducing effect of levetiracetam on CYPs. Phenobarbital (2 mM), beta-naphtoflavone (40 microM), dexamethasone (1 microM), and phenytoin (up to 300 microM) were tested as positive controls. When added to cells for 48 h, all the positive controls increased 7-ethoxycoumarin O-deethylase activity demonstrating the inducibility of CYPs in the present culture conditions. By contrast, levetiracetam did not affect the activity up to 1 mM. The highest levetiracetam concentrations examined in the above in vitro studies are well in excess of those measured in the plasma of patients receiving therapeutic doses. It is thus concluded that levetiracetam is unlikely to produce pharmacokinetic interactions through inhibition of CYPs, UGTs, and epoxide hydrolase. Furthermore, based on the in vitro assays with rat hepatocytes, it could be speculated that levetiracetam does not act as a CYP inducer.

Syphilis in 1986

Symptoms of syphilis have evolved over the ages. In the 16th century, they were essentially cutaneomucous ones. While the intensity of the symptoms decreased localization of the infection in the various organs--mainly those of the cardiovascular and nervous system--gradually appeared. Over a period of years following the introduction of penicillin therapy, the cutaneous and visceral stages became less common. Reminder of the chief serological reactions and of some aspects of the experimental syphilis in the rabbit, similar to certain forms of human syphilis--a strong but late penicillin therapy has been proven ineffective in humans as well as in animals. It is to be regretted that numerous methods of using penicillin (all over the world), had been, from the beginning--except in a few cases--of a purely empirical nature. The authors emphasize--with proof to support their opinion--the failure of antibiotic therapy, which can explain the recent reappearance of hepatic and nervous localizations that had disappeared for 30 years. Despite views to the contrary the authors conclude that penicillin has in no way resolved all the problems raised by the treatment of syphilis.

[Activity of thiamphenicol in the early stage of syphilis]

Possible activity of thiamphenicol on Treponema pallidum during single-dose treatment of gonococcal infection with 10 tablets of 0.250 mg each was investigated using a new, more accurate method. We found that, under the conditions of our study, thiamphenicol fails to kill T. pallidum, exhibiting only incomplete activity. Thus, thiamphenicol taken during incubation of syphilis may delay or inhibit the emergence of primary manifestations but fails to achieve bacteriologic sterilization of T. pallidum acquired concomitantly with gonococcus. Clinical and serologic evidence of syphilis should therefore be looked for routinely three and six months after treatment.

[A method for evaluating the activity of antibiotics during the early phase of syphilitic infection]

The aim of our study is to evaluate the activity of antibiotics on Treponema pallidum (Tp) in the early stage of syphilis. Serum elimination kinetics for the antibiotic under study are first determined in rabbits. Four groups of seronegative rabbits are then submitted to intratesticular injection of a calibrated inoculum of Tp (Nichols virulent strain). The antibiotic is given simultaneously (TO), 3, 6 or 10 days after inoculation. Treated animals, as well as a control group of simultaneously infected untreated animals, are monitored for physical and serological changes for three months. Every animal is then tested according to the techniques of experimental rabbit syphilis to provide final conclusions. The technique investigates the direct activity on Tp of given serum concentrations of an antibiotic, and therefore the therapeutical effectiveness of an agent in a selected dosage. It also allows demonstration of sublethal activity on Tp of serum concentrations which are adequate for treating other concurrent infections (including STD) but not syphilis.

Is penicillin therapy always infallible in syphilis?

Penicillin is undoubtedly the antibiotic most effective on Treponema pallidum, but is it possible to prescribe it according to a standard regimen? Experimentation proves that such a uniform therapeutic plan cannot be determined for the following reasons: 1) Treponema pallidum may divide every 30 to 33 hours, but this concept is only established during the period of exponential growth in the initial lesion. Moreover, if Treponema pallidum are very quickly disseminated throughout the organism, then they do not divide at the same rate. In addition, we take into account a whole series of factors which can interfere with their rate of multiplication. 2) A penicillinemia of 0.03 U/ml may kill all the Treponema pallidum when they divide, but Dr. Eagle's data, although this would be a fairly active serum level, showed that the effective maximal serum concentration should be far higher, about 0.820 U/ml. The experimental data prove it is not possible to point out an accurate correlation between blood and tissue levels; thus, the penicillin levels in the cerebrospinal fluid are about 1/100 lower than those obtained in the serum. Among other factors it is necessary to take into account not only the age of the patient but also the penicillin complex chosen. Although the total of injected penicillin can be the same, the kinetics of serum levels are essentially variable, both regarding the increase of levels and duration according to the drug used. 3) As noted it follows that penicillinotherapy prescribed early with high and prolonged doses may allow a bacteriologic sterilization of primary syphilis.(ABSTRACT TRUNCATED AT 250 WORDS)

[Syphilis. An up-to-date physio-biological view of the main topics. IV.--The problem of the treatment by penicillin (author's transl)]

Can penicillin be considered as an infallible treatment for syphilis? Some practitioners have hoped and even believed that this antibiotic would be able to eradicate this infection. To support their thesis, they have put forward an uniform standard therapeutic plan capable of being applied to any stage of the disease and which is based upon the following syllogism: a) all T.p. would divide every 30-33 hours. b) a level of penicillinemia of 0.03 IU/ml would destroy all Treponema when they divide. c) thus, a penicillin therapy administered 3 times giving such levels in serum during a period of 33 hours would produce a bacteriological sterilization of the infected organism. But statistics have shown that these conceptions were wrong. As a matter of fact: 1) every biological research has clearly proved that it is wrong to assert such a rhythm of division for all T.p. Since this multiplication is submitted to a succession of factors that we know more or less well, thus, during the latency phase, T.p. vegetate inside the tissues without apparently multiplying so quickly. 2) For lack of being able to cultivate T.p., it is not possible to state which is the activity level of penicillin on this germ. 3) Finally, the kinetic elimination of penicillin varies extremely, particularly depending on the drug which is used with patients, and on the localization of these germs. All experimental and clinical studies agree and insist on the fact that penicillin therapy must be given early in the infection, at a prolonged and high dose; results having to be estimated on the serological answers, especially with repeated TPI and FTA tests. As far as the late phases of the disease are concerned, for lack of being able to cultivate T. pallidum and because we do not have any absolute criterion of any bacteriological sterilization, the serological answers being often positive, circumspection has always to be a rule: it is better to admit what we do not know rather than to assert without any proof.

[Syphilis. An up-to-date physio-biological view of the main topics. III -- The problem of immunity (author's transl)]

The problem of immunity in Syphilis is a very complex problem which is tightly bound to healing. But for lack of being able to grow T. pallidum and as we are without any absolute criterion of bacteriological sterilization, the only method we have to be able to consider this study is to have recourse to experimentation upon animals. Two theories had been proposed to give an explanation about this phenomenon occurring during a late treated syphilis: on one side, for Kolle, Evers and Neisser, immunity in syphilis would be due to a premunition given by the only persistence in the organism of T.p. having still kept all their virulence. On the other hand, as far as Chesney and Kemp are concerned it would be a true immunity, obtained before the application of any therapeutic treatment, but which is not due to persistence of T.p. in tissues. However, recent works have proved, and this has been confirmed by several searchers, that a penicillin therapy, even at a high dose, given six months after the infection outset, is no longer able of destroying all T.p. Immunity in syphilis would then be due to a modification of tissular receptivity kept by the persistence of T.p. vegetating in the organism in a commensal state. As far as the nature of this immunity is concerned, all the present research would lead to prove that this refractory state would not be due to tumoral properties, but more likely to tissular properties and probably to cell mediated phenomena. Similar research carried out in man has created an opportunity to demonstrate these facts similar to those observed in experimentations upon animals. They particularly prove that a persistent serology over a long period is not due to a "cicatrice sérologique" (Serological marker) but to the keeping of T.p. in a quiescent state. However, it is a more or less relative immunity which is concerned, depending upon a very large number of factors that are far from being elucidated.

[Syphillis. An up-to-date physio-biological view of the main topics. II- The evolutive process of experimental syphilitic infection and a comparison with clinical symptoms in man (author's transl)]

For lack of being able to grow Treponema pallidum, the only possibility that we have to study its biological behavior is to have recourse to experimentation upon animals. The stade comprising primary and secondary syphilis is characterized by visible "warning signals" which are not serious for the patient himself. But all their importance lies in the fact that they reveal the dissemination of T. pallidum inside the whole body. Thus, the healing alone or the disappearance of the lesion does not necessarily mean that it is cured. As a matter of fact, after that phase, infection may proceed "á bas bruit", as a chronic affection, which will come to light later, 10 to 15 years or more after the primary stage, as a visceral phase involving mainly cardiovascular or central nervous system. Those impairments cannot then be cured. Now, during that long period of latency, we are totally without any absolute criterion of "bacteriological sterilization", for we do not know precisely the physio-pathological meaning of these numerous serological reactions which are at out disposal and subsequently we are obliged to interpret them through divergent opinions because these techniques are not established on scientific method but are based upon empiric knowledges.

[Syphilis. Current physiobiological data. I. The bacteriological problem]

For lack of being able to grow Treponema pallidum, the only method which allows us to study the biology of this germ and the physiopathology of this infection lies in researches in experimental syphilis. After pointing out the different aspects of Treponema pallidum, either with light microscopy or electron microscopy, the authors review the different kinds of reproduction suggested by syphiligraphs, the recent trials to cultivate the treponema, and the processes of elimination. Then, they examine the biological properties and the antigenic structure of T.p. as it has been established by comparison with cultivable spirochetes. To end with, the authors show that both the TPI test and the FTA test are two very specific reactions; these tests mean nothing but the fact that the patient has been in contact with the antigens of Treponema pallidum and the quantitative tests cannot be considered as expressing the infectious potential capacity.

Kinetic study of serum penicillin concentrations after single doses of benzathine and benethamine penicillins in young and old people

In a comparative kinetic study of the serum concentrations of two penicillin complexes--medium-long-acting (benethamine penicillin) and long-acting (benzathine bipenicillin)--after a single injection in young adults and elderly people, the following results were confirmed statistically: (a) age was a major factor in the variations in serum penicillin concentrations and in their persistence in the serum; (b) the penicillin was absorbed faster in young than in elderly subjects even when a long-acting complex was used; (c) serum concentrations below the level regarded as lethal for treponemes appeared much earlier and more frequently in young than in old people; and (d) the bioequivalence between penicillin preparations could not be estimated solely for the number of units of the agent used but from the bioavailability of the chosen formulation. Thus a uniform and standard penicillin dosage allowing no safety margin may help in the superficial healing of a syphilitic chancre or the resolution of a roseola but it will certainly be insufficient to kill Treponema pallidum. It seems essential therefore to provide an antibiotic cover at high dosage over a long period of time.

Modified method of filtering cerebrospinal fluid and aqueous humour for the detection of treponemes. Proof of the persistence of their vitality in rabbits

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Experimental rabbit syphilis

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