Redescription of Heligmosomoides neopolygyrus, Asakawa and Ohbayashi, 1986 (Nematoda: Heligmosomidae) from a Chinese rodent, Apodemus peninsulae (Rodentia: Muridae); with comments on Heligmosomoides polygyrus polygyrus (Dujardin, 1845) and related species in China and Japan.

Heligmosomoides neopolygyrus, Asakawa and Ohbayashi, 1986 (Nematoda, Heligmosomoidea) is redescribed from Apodemus peninsulae from Rangtang, Sichuan, China. A morphological review of the Heligmosomoides spp. belonging to the "polygyrus line" proposed by Asakawa (1988) is made using new characters. This enabled us to distinguish two subspecies in Mus musculus (Heligmosomoides polygyrus bakeri from Japan and H. p. polygyrus from China) and two valid species in Apodemus spp. (H. neopolygyrus from Japan (in A. peninsulae) and from China (in A. agrarius) and H. asakawae from China (in A. uralensis)). Three parasite species of A. agrarius and A. peninsulae, previously identified by Asakawa et al. (1993) as H. neopolygyrus, are considered to be Heligmosomoides incertae sedis. This is the first report of H. neopolygyrus in A. peninsulae from China.

Description of a new species of Heligmosomoides (Nematoda: Heligmosomidae) parasitic in Microtus limnophius (Rodentia: Cricetidae) from Rangtang, Sichuan, China.

Heligmosomoides craigi n. sp. (Nematoda: Heligmosomoidea) is described from Microtus limnophilus Büchner, 1889 (Rodentia: Cricetidae) from Rangtang, Sichuan, China. It is related to H. protobullosus Asakawa, 1987 and H. longispiculum Tokobaev & Erkulov, 1966 both parasites of Microtus spp. from Japan and USSR, respectively by the following features: a ratio of spicule length/body length of more than 45% and rays 9 shorter than rays 10. The new species is differentiated by rays 8 being closed to rays 6 and 19-22 cuticular ridges versus 14 in H. protobullosus (synlophe not described in H. longispiculum). H. longicirratus (Schulz, 1954) also a parasite of Microtus sp. from the USSR is the most closely related species based on the number of cuticular ridges (20) and the ratio of spicule length/body length (48% versus 50%). There are no illustrations of this species and the female has not been described; for that reason, it is not possible to compare it accurately with our specimens.

Numerical response of a helminth community in the course of a multi-annual abundance cycle of the water vole (Arvicola terrestris).

The impact of parasitism on population dynamics is determined in part by the numerical responses of parasites during population fluctuations of their hosts. Vole populations fluctuate in multi-annual cycles allowing such responses to be studied over successive phases of population growth, abundance and decline. We investigate how a helminth community (5 nematode and 7 cestode species) evolved over a full 6-year Water Vole (Arvicola terrestris) population cycle. Brillouin and individual parasite species richness (IPSR) indices were used to measure the numerical response of the parasite community. We report a correlation between levels of parasite intensity and vole population cycle phases. Both indices were consistently higher during pre-decline and decline phases for male and female voles alike. The numerical response of the parasite community suggests that populations may be regulated by parasitism and that studies of this mechanism should allow both for the cyclic or non-cyclic character of the host populations and for the response of the broadest possible set of the local parasite community.

Frenkelia parasites in a small mammal community. Dynamics of infection and effect on the host.

A community of small mammals, Clethrionomys glareolus, Arvicola terrestris, Microtus arvalis, M. agrestis, M. subterraneus, Apodemus spp. and Sorex spp., was studied as hosts of Frenkelia glareoli and F. microti in Fronche-Comté (France). They were monitored in spring, summer and autumn on an area of about 1,350 ha comprising open field, hedgerow network and forest. Among 1,714 small mammals examined between July 1992 and October 1993, 47% (178/376) of C. glareolus, 9.9% (14/139) of A. terrestris and 1.3% (4/311) of Apodemus spp. were infected by F. glareoli. The prevalence of infection with F. microti was 9.2% (66/716) in M. arvalis and 8.2% (6/73) in M. agrestis. M. subterraneus and Sorex spp. were not infected. The maintenance of each parasite in a rural landscape is assured both by a forest and a grassland host. Multiple logistic regression showed that prevalence was highly age-dependent, with an apparent seasonal pattern. Prevalence varied between 30% in summer and 60% in early spring for F. glareoli in C. glareolus and between 3% in autumn to 30% in early spring for F. microti in M. arvalis. The year, habitat, host sex, relative density had no impact on prevalence. In M. arvalis only, sexually active voles were preferentially uninfected, indicating a possible impact of this parasitism on fertility.

Interactions between landscape changes and host communities can regulate Echinococcus multilocularis transmission.

An area close to the Qinghai-Tibet plateau region and subject to intensive deforestation contains a large focus of human alveolar echinococcosis while sporadic human cases occur in the Doubs region of eastern France. The current review analyses and compares epidemiological and ecological results obtained in both regions. Analysis of rodent species assemblages within quantified rural landscapes in central China and eastern France shows a significant association between host species for the pathogenic helminth Echinococcus multilocularis, with prevalences of human alveolar echinococcosis and with land area under shrubland or grassland. This suggests that at the regional scale landscape can affect human disease distribution through interaction with small mammal communities and their population dynamics. Lidicker's ROMPA hypothesis helps to explain this association and provides a novel explanation of how landscape changes may result in increased risk of a rodent-borne zoonotic disease.

[Aortic stenosis with left ventricular dysfunction]. / Rétrécissement aortique avec dysfonction ventriculaire gauche.

Patients affected by aortic stenosis with severe systolic left ventricular dysfunction have a poor spontaneous prognosis. The results of valvular replacement are globally good, at the price of an acceptable operative mortality. The existence of surgical failure has however prompted much work aimed at better definition of prognostic factors and for proposing new methods of specifying surgical indications. In this article based on a review of the literature, we discuss the physiopathology of left ventricular dysfunction, predictive factors for operative risk and survival, and the elements to be taken into account in order to adjust therapeutic decisions in these severe cases.

An epidemiological and ecological study of human alveolar echinococcosis transmission in south Gansu, China.

Human alveolar echinococcosis (AE) is usually a rare, highly pathogenic zoonotic disease, transmitted across the northern hemisphere between fox and rodent hosts. In China the first cases were described in 1965; however very few epidemiological studies have been undertaken since. Following identification in 1991 of a serious focus of human AE in south Gansu province, detailed village-based community and ecological studies were carried out between 1994 and 1997. Hepatic ultrasound mass screening with serological testing (five tests) identified 84/2482 new AE cases (3%). An overall prevalence of 4.1% (135/3331) was recorded for the area when previous cases were also included. Based on a seropositive result only, without an ultrasound scan indication, no additional AE cases were identified. Of the evolutive AE cases, 96% were seropositive in at least one test, while up 15-20% of individuals who exhibited hepatic calcified lesions and 12-15% exhibiting hepatic nodular lesions were seropositive for specific Em2 or Em18 antibodies. Village (n=31) human AE prevalence rates varied from 0 to 15.8%. Questionnaire analysis indicated that total number of dogs owned over a period was a risk factor (P<0.006), but not a history of red fox hunting (P>0.6). Rodent ecology studies revealed an association between density indices of voles (Microtus limnophilus) and village AE prevalence rates, on the one hand, and village landscape characterised by a ratio of scrub/grassland to total area above 50% (P<0.005). Long-term transmission of Echinococcus multilocularis and risk of zoonotic infection of south Gansu farmers may be related ultimately to a process of deforestation driven by agriculture. This in turn probably results in creation of optimal peri-domestic habitats for rodents that serve as intermediate host species (such as M. limnophilus) and subsequent development of a peri-domestic cycle involving dogs.

Epidemiology of alveolar echinococcosis in Xinjiang Uygur autonomous region, China: a preliminary analysis.

The Xinjiang Uygur autonomous region (XUAR) in north-western China is known to be endemic for Echinococcosis multilocularis, the causative agent of human alveolar echinococcosis (HAE). Despite regular reports of HAE cases in their region, very little is known about the local epidemiology of the disease or the transmission of E. multilocularis. The epidemiology of HAE in Xinjiang has now been investigated by the analysis of data collected from the medical records of 157 clinical cases who had attended the four main hospitals in the region. These data indicate that the disease is relatively common in the Altai, western Junggar, and Tianshan mountain ranges, whereas the Tarim and Junggar basins are likely to be of low endemicity. The prevalence of the disease in the Kunlun mountains is not clear. Semi-nomadic groups, especially those of Kazakh or Mongol origin, have a higher risk of infection than other ethnic groups. Prevalence of the disease in humans appears to be correlated with aspects of the local climate, such as annual precipitation and temperature. Red foxes, Microtinae, Ochotona spp. and Marmota spp. may be important hosts of E. multilocularis in the XUAR, sustaining the transmission cycles of the parasite.

Karyological and dental identification of Microtus limnophilus in a large focus of alveolar echinococcosis (Gansu, China).

A study of voles (Arvicolidae, Rodentia) from Gansu (China) designed to identify a potential host of Echinococcus multilocularis, responsible for human alveolar echinococcosis, leads to a general analysis of Microtus limnophilus population karyotypes, M1 of M. oeconomus populations from all of Eurasia and of M. limnophilus of Mongolia. The Microtus of Gansu belonging to the nominal subspecies M. limnophilus limnophilus (2n = 38; NF = 58) differs markedly in size and shape of M1 from the M. limnophilus of Mongolia, which must therefore be considered as a new subspecies M. limnophilus of malygini nov. ssp. (2n = 38; NF = 60) and the M. oeconomus of Mongolia should be ranked as M. oeconomus kharanurensis nov. ssp. (2n = 30; NF = 60).

Paradoxical embolism following acute pulmonary embolism: diagnosis and outcome.

We report on ten cases of paradoxical embolism that occurred following pulmonary embolism and emphasize the echocardiographic contribution. Two patients had a thrombus trapped in a foramen ovale. An embolectomy was performed on one of those patients and the outcome was post-operative death. The other patient died suddenly prior to planned surgery. The remaining eight had inter atrial communication or foramen ovale that were highly patent upon contrast echography. Two of them who presented cardiogenic shock died rapidly despite resuscitation measures. The remaining six patients were treated medically with anticoagulants and have experienced no recurrence of embolism after a mean follow up 34+/-31 months.

[Malignant cardiac lymphoma. Diagnosis by echocardiography]. / Lymphome malin tumoral de localisation cardiaque. Diagnostic par échocardiographie.

The authors report a case of cardiac malignant non-Hodgkin lymphoma. The initial clinical presentation suggested recurrent angina in a patient who had undergone angioplasty of the left anterior descending artery two years previously. Echocardiography showed severe left ventricular dysfunction with apical and septal akinesia and also allowed visualisation of two oval masses in the right ventricle without dilatation of the right heart chambers. Transoesophageal echocardiography confirmed these abnormal echos which corresponded to tumour invasion of not only the right heart chambers but also the interatrial septum, the left atrial appendage and the descending thoracic aorta. Histological diagnosis of lymphoma was made from an excision biopsy of a mass in the calf muscle. The post-mortem examination confirmed the presence of a highly malignant T-cell non-Hodgkin lymphoma. The patient rapidly deteriorated and died during the first session of chemotherapy.

[Chronic constrictive pericarditis apropos of 3 cases disclosed by refractory cardiac failure]. / Péricardite chronique constrictive à propos de trois cas révélés par une insuffisance cardiaque réfractaire.

Chronic constrictive pericarditis is a difficult diagnosis and may present atypically. The authors report three clinical cases and review the diagnostic strategy of constrictive pericarditis. In these three patients, the diagnosis was finally made after one or more years of symptomatic disease and after several diagnostic work ups and ineffective treatments. In cardiac failure, pericardial calcification is often not observed on chest X-ray and Doppler echocardiography is usually the diagnostic investigation. Adiastole presents with dilatation of the vena cava and atria, contrasting with normal ventricles without major valvular disease. Doppler echocardiography enables distinction of constrictive pericarditis from restrictive cardiomyopathy: normal myocardium, thickened pericardium, specific septal motion, inspiratory increase in right ventricular dimensions, premature opening of the pulmonary valve, important variations in ventricular filling with respiration, expiratory diastolic reflux in the hepatic veins. Catheterisation confirms adiastole and may suggest a pericardial aetiology in characteristic cases, associated with only mild increases in pulmonary artery pressure. If need be, the pericardial thickening > 4 mm may be observed with magnetic nuclear resonance imaging and, when a doubt remains with respect to the diagnosis of cardiomyopathy, the absence of fibrosis on endomyocardial biopsy provides the diagnosis and indication for curative surgery: pericardectomy.

[Recording of pulmonary venous flow with Doppler echocardiography; normal and pathological aspects]. / En registrement du flux veineux pulmonaire par échocardiographie Doppler; aspects normaux et pathologiques.

The appearances of pulmonary venous flow Doppler echocardiography have been the subject of many reports. The recording is obtained by transthoracic or transoesophageal pulsed Doppler examination. The value of this parameter in the study of left ventricular diastolic function has been clearly established. The transoesophageal approach is mainly useful for quantifying mitral regurgitation and for monitoring left atrial pressure during surgery. This review of the literature describes the methods of recording and the normal appearances of pulmonary venous flow, and then discusses the different variations encountered in pathological conditions.

Assessment of severity of mitral regurgitation by measuring regurgitant jet width at its origin with transesophageal Doppler color flow imaging.

BACKGROUND: The ability of transesophageal color Doppler echocardiography to provide high-resolution images of both cardiac structure and blood flow in real time is advantageous for many clinical purposes. This study was performed to determine the utility of the regurgitant jet width at its origin measured by transesophageal Doppler color flow imaging in the assessment of severity of mitral regurgitation. METHODS AND RESULTS: Sixty-three consecutive patients with mitral regurgitation underwent transesophageal color Doppler examination, and the diameter of regurgitant jet at its origin was measured. Both right and left cardiac catheterizations were performed within 24 hours of Doppler studies, and angiographic grading of mitral regurgitation and regurgitant stroke volume were evaluated. There was a close relation between the jet diameter at its origin measured by transesophageal Doppler color flow imaging and the angiographic grade of mitral regurgitation (r = 0.86, p less than 0.001). A jet diameter of 5.5 mm or more identified severe mitral regurgitation (grade III or IV) with a sensitivity of 92%, specificity of 92%, and positive and negative predictive values of 88% and 95%, respectively. In 31 patients with isolated mitral regurgitation, the jet diameter correlated well with the regurgitant stroke volume determined by a combined hemodynamic-angiographic method (r = 0.85, p less than 0.001). A jet diameter of 5.5 mm or more identified a regurgitant stroke volume of 60 ml or more with a sensitivity of 88%, specificity of 93%, and positive and negative predictive values of 94% and 87%, respectively. CONCLUSIONS: The regurgitant jet width at its origin measured by transesophageal Doppler color flow imaging provides a simple and useful method of measuring the severity of mitral regurgitation, and it may allow differentiation between mild and severe mitral regurgitation.

[Quantification of mitral valve diseases by Doppler]. / Quantification des valvulopathies mitrales par Doppler.

Echo Doppler makes a fundamental contribution to the non-invasive quantification of mitral valve disease. It enables calculation of gradients and of orifice surface area in mitral stenosis. The quantification of mitral insufficiency is also possible though more difficult: it is based upon the combination of semi-quantitative and quantitative methods, in particular the calculation of regurgitation fraction obtained by comparison of flow rates at different orifices in cases of pure regurgitation. Finally, the calculation of pulmonary artery pressures from a Doppler record in tricuspid and pulmonary insufficiency can be used to assess the effects of mitral valve disease on the pulmonary circulation. Echo Doppler thus provides a reliable non-invasive hemodynamic assessment of mitral valve disease and should lead to a reduction in the number of invasive investigations in this type of valve disease.

[Determination of cardiac output by Doppler ultrasonics. Principle, techniques and limitations]. / Détermination du débit cardiaque par écho Doppler. Principe, techniques, limites.

The development of quantitative applications of Doppler ultrasound for the measurement of cardiac output was a lengthy and difficult process. These applications call for rigor of the part of the ultrasound cardiographer and a sufficiently echoic patient. Numerous studies have demonstrated the reliability of Doppler ultrasound in determining aortic flow. A high degree of consensus has emerged for measuring aortic areas and velocities at the ring. Doppler ultrasound quantification of the pulmonary flow has been validated in children. In adults, measurement of the pulmonary ring is often difficult and may lead to major errors in the estimation of the flow rates. The determination of mitral flow is also possible, either at the ring or at the tip of the mitral funnel. A few publications highlight the value of Doppler ultrasound in evaluation of tricuspid flow, however, these results require confirmation.