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D Morvan

Publications and source records attributed to D Morvan.

17 recordsLinked to original sources
PubMed1992

Model-based determination of cut-off values for left ventricular hypertrophy from echocardiographic myocardial mass data.

1. The left ventricular myocardial mass is a measurement that is easy to obtain by echocardiography. It is currently used for the definition of left ventricular hypertrophy, but cut-off values are often critical, since they depend on covariates of left ventricular myocardial mass such as sex, age, body surface area, physical training, blood pressure, etc. As it is very difficult in any laboratory to obtain a sufficient number of normal subjects for the establishment of left ventricular myocardial mass experimental distributions, we propose a non-linear model for the calculation of echocardiographic left ventricular myocardial mass distribution in normal subjects, from personal and literature data. left ventricular myocardial mass probability density function was computed from the following two assumptions: the joint distribution of the internal and external left ventricular diameters is assumed to be bivariate normal, and the relation between left ventricular myocardial mass and ventricular diameters is given by the formula of Devereux & Reicheck (Devereux, R. B. & Reicheck, N. Circulation 1977; 55, 613-8). 2. The Gaussian assumption was tested by using skewness tests. The model was further developed for the myocardial mass index distribution. The calculated probability density functions were compared with experimental data and showed very good agreement. Furthermore, they were used to define cut-off values of left ventricular hypertrophy at selected false-positive ratios. Finally, since left ventricular myocardial mass may vary under normal conditions with co-variates, the model may provide co-variate-matched cut-off values for any, even small, series of non-diseased control subjects.

Adult↗
PubMed1992

Cardiomyopathy in Friedreich's ataxia: a Doppler-echocardiographic study.

Heart involvement is frequent in Friedreich's ataxia (FA), the most prevalent of the spino-cerebellar degenerative diseases, which is inherited with an autosomal recessive pattern. However, the pathophysiological link between cardiac and neurological disorders is not yet clearly established. We compared a group of 10 patients with FA to a control group (C) of 16 normal subjects, using Doppler-echocardiography. To see whether cardiac involvement was specific to FA, the data of patients with FA were also compared to those of patients with autosomal dominant olivo-ponto-cerebellar atrophia (OPCA), another spino-cerebellar degenerative disease. There was an increase in left ventricular mass index in FA (154 +/- 9 g.m-2 vs 99 +/- 7 g. m-2 in C, P < 0.001), systolic function was normal, the ejection fraction (EF) slope and E/A ratio were decreased (85 +/- 9 mm.s-1 vs 130 +/- 7 mm.s-1 in C, P < 0.001 and 1.5 +/- 0.1 vs 1.7 +/- 0.1 in C, P < 0.01, respectively), while the isovolumic relaxation period was increased (96 +/- 3 ms vs 92 +/- 2 ms in C, P < 0.01). Deceleration time and time-velocity integrals of A wave to total mitral flow were not modified. In OPCA only the E/A ratio was decreased (1.5 +/- 0.1 vs 1.7 +/- 0.1 in C, P < 0.05). These data show the presence of cardiomyopathy in FA with left ventricular hypertrophy and suggest the presence of diastolic function abnormalities. The cardiomyopathy seems specifically associated with FA and not to spino-cerebellar degenerative disease in general.

Adolescent↗
PubMed1992

Temperature changes induced in human muscle by radio-frequency H-1 decoupling: measurement with an MR imaging diffusion technique. Work in progress.

To investigate temperature increases in tissues during magnetic resonance (MR) imaging or spectroscopy, the authors measured temperature changes in vitro and in vivo (leg of a volunteer) in a condition simulating hydrogen-1 decoupling in MR spectroscopy. Noninvasive measurements were obtained by using the temperature dependence of the translational diffusion coefficient of water. Temperature was measured at 0.5 T (86 MHz) by using a stimulated-echo sequence that included intense gradient pulses and a procedure reducing sensitivity to bulk tissue motion. Calibration curves of the diffusion coefficient against thermocouple-measured temperature were obtained for a gelatin phantom and bovine muscle. Temperature changes were 5.3 degrees C +/- 0.5 at 2.5 cm from the coil in gelatin and 7.7 degrees C +/- 0.5 at 0.7 cm in bovine muscle. The temperature changed by 4.9 degrees C +/- 1.9 at 2.2 cm from the coil in the calf muscle of a volunteer. The H-1 decoupling protocol can be adapted (modifications in transmission power, duty cycle) to reduce heating effects to below safety recommendations.

Animals↗
PubMed1991

Cardiac hypertrophy and function in asymptomatic acromegaly.

Heart disease frequently occurs in advanced acromegaly. In order to investigate cardiac mass and function in acromegaly in the absence of obvious cardiac disease, we performed Doppler echocardiography in 15 asymptomatic acromegalic patients (six of them had systemic hypertension). The data were compared with those of a group of 10 age-matched controls. Left ventricular mass index (LVMI) was increased in acromegaly (110 +/- 32 vs 32 +/- 12 g m-2, P = 0.02), but shortening fraction and systolic time intervals did not differ. Mitral EF slope was decreased (80 +/- 21 vs 101 +/- 30 mms-1, P less than 0.02), while the duration of the isovolumic relaxation period (IRP) was increased (92 +/- 13 vs 69 +/- 16 ms, P less than 0.01). Hypertensive acromegalic patients (n = 6) had a higher LVMI than normotensive acromegalic patients (n = 9) (133 +/- 27 vs 94 +/- 24 g m-2, P = 0.02) and this was confirmed by a meta-analysis of data in the literature: the prevalence of hypertrophy was 76% in the presence of hypertension vs 50% in its absence, P less than 0.002. IRP was prolonged in normotensive acromegalic patients vs normal controls (90 +/- 11 vs 69 +/- 16 ms, P less than 0.01). In conclusion, subclinical cardiac abnormalities occur frequently in acromegaly in the absence of obvious heart disease, and hypertrophy is observed in asymptomatic hypertensive acromegaly. Moreover, diastolic abnormalities are found in asymptomatic acromegaly and could be caused by several heart-related factors.

Acromegaly↗
PubMed1990

Discriminant factor analysis of 31P NMR spectroscopic data in myopathies.

Discriminant factor analysis (DFA) enables one to distinguish among diagnostic groups using diagnostic variables. It provides discriminant functions that are linear combinations of the diagnostic variables and that optimally separate diagnostic groups. It was used to enhance the accuracy of 31P NMR data in the diagnosis of myopathies. DFA allowed a good separation of normal subjects, congenital neuromuscular disorders with type I fiber predominance, and McArdle's diseases. It elicited an unexpected homogeneity of idiopathic rhabdomyolyses, the metabolic origin of which is unknown, and suggested that the abnormality could involve the mitochondrial oxidative metabolism in some of them. In mitochondrial myopathies, an expected heterogeneity is shown by DFA. It may allow an automatic diagnosis of some myopathies from 31P NMR data or guide biochemists by comparing biochemical features of a new patient to those of previously established groups.

Adult↗
PubMed1990

[Role of arterial hypertension in the cardiac involvement of acromegaly].

Cardiac disease is common in acromegaly. Several mechanisms have been implicated: hypertension, coronary artery disease, valvular heart disease, endocrinopathies including "acromegalic cardiomyopathy". Fifteen consecutive patients with acromegaly, aged 48 +/- 13 years and treated for 4 +/- 5 years, underwent Doppler echocardiography. The patients had no cardiovascular symptoms: 6 had hypertension for 10 +/- 7 years and were compared with a group of 10 control subjects of the same age (48 +/- 17 years). The myocardial mass index (MMI) was higher in acromegaly (110 +/- 32 vs 82 +/- 12 g/m2, p = 0.02), left ventricular enddiastolic dimensions where comparable (48 +/- 7 vs 48 +/- 5 mm, NS) fractional shortening was slightly greater (0.37 +/- 0.04 vs 0.34 +/- 0.04, p = 0.07) as was velocity of shortening (NS) and the ratio of systolic time intervals (NS). The mitral EF slope was decreased (80 +/- 21 vs 101 +/- 30 ms; p less than 0.02); the ratio of the amplitudes of the E and A waves was a little decreased and the isovolumic relaxation phase was increased (92 +/- 13 vs 69 +/- 16 ms; p less than 0.01). Hypertensives (N = 6) had higher MMI (133 +/- 27 vs 94 +/- 24 g/m2, p = 0.02). Normotensive patients had larger isovolumic relaxation periods than control subjects (90 +/- 11 vs 69 +/- 16 ms, p less than 0.05). These results show that in the infraclinical phase, the heart in acromegaly is hypertrophied, not dilated. Hypertension plays a significant role in the development of this hypertrophy. Left ventricular systolic function is normal but diastolic function is impaired.

Acromegaly↗
PubMedDate not supplied

Correlation of MR changes with Doppler US measurements of blood flow in exercising normal muscle.

Muscle data from phosphorus-31 magnetic resonance (MR) spectroscopy and hydrogen-1 MR imaging and popliteal artery data from duplex Doppler ultrasound were compared during an exercise test of the anterior compartment of the leg, in nine healthy volunteers. Significant variations (mean +/- standard deviation) were observed at the end of exercise versus rest in intracellular pH (pHi) (6.32 +/- 0.02 vs 7.02 +/- 0.04, P < .001), T2 (38.2 msec +/- 2.3 vs 29.5 msec +/- 1.1, P < .001), and popliteal output (652 mL/min +/- 232 vs 149 mL/min +/- 65, P < .001). These variables showed the following significant correlations at the end of exercise: T2 and pHi (r = -.784, P < .01), T2 and popliteal output (r = .737, P < .03), and pHi and popliteal output (r = -.902, P < .001). However, during recovery, the T2 curve was significantly different from those of pHi and popliteal output. This suggests that even if circulatory conditions play a role in the maximum T2 variation during exercise, they do not directly explain T2 changes. Furthermore, the correlations involving pHi suggest the role of the metabolism of exercising muscle in transcapillary fluid movement.

Adult↗
PubMedDate not supplied

[Culicidae of the French Territory of Afars and Issas. The genera Aedes, Culiseta, Uranotaenia and Mimomyia].

During an entomological survey conducted in French Territory of Afars and Issas from november 1973 to june 1975, the following species were collected: Aedes caspius, A. vittatus, Culiseta longeareolata, Uranotaenia balfouri, Mimomyia mimomyiaformis, M. mediolineata. To these mosquitoes, we must add the record of A. aegypti larvae on a dhow berthing in Djibuti while this mosquito does not exist actually in the Territory. The epidemiological importance of these culicids is discussed.

Aedes↗
PubMedDate not supplied

[The question of endemic malaria in Republic of Djibouti (author's transl)].

Since 1973 autochthonous cases of malaria due to P. Falciparum have been reported among local population of French Afars and Issas Territory; 191 cases observed between 1973 and 1976 are recorded. Their monthly distribution and geographical repartition are studied, jointly with the distribution of A. gambiae which has been recently collected in the Territory. This study shows a significant correspondance between the presence of A. gambiae and the malaria cases observed which did not come from neighbouring countries. We may, then, expect the development of small disseminated foci, resulting from the simultaneous introduction of both the parasite and its anopheline vector. This brings about a new epidemiological situation for the Territory.

Africa, Eastern↗
PubMedDate not supplied

[Current aspects of human salmonellosis in Upper Volta. Study carried out at Centre Muraz (Bobo-Dioulasso) from 1966 to 1977: isolation of 1,013 Salmonella strains].

In a long term research programme of Centre Muraz a study on salmonellosis in Upper Volta has been carried out, at Bobo-Dioulasso, from 1966 to 1977. Investigations have been executed at Centre Muraz, at Bobo-Dioulasso hospital and at Ouagadougou hospital. All the strains of Salmonella were collected at Centre Muraz by biology laboratory, which is a reference service for Upper Volta. This country is include; among the 32 countries which collaborate with W.H.O. and are involved in the world epidemiological surveillance of salmonellosis. For twelve years, 1.013 Samonella strains have been isolated : 1.002 from man and only 11 from animals. The study, which is presented, deals with human salmonellosis. These diseases have been considered from several points of view : bacteriology, clinic, treatment and epidemiology. The various origins of these strains have been specified. The different technics used for diagnosis are discussed briefly : hemoculture (for typhoïd fever and few other types of salmonellosis), coproculture (for "minor" salmonellosis) are the most common and useful methods. Among the 1.013 which have been found, S. typhi is highly predominant (67 p. 100). In the other hand, S. dublin and S. typhi murium play an important role in the various serotypes which occured. A total of 76 serotypes, already known elsewhere, but found for the first time in Upper Volta, have been observed. Three new serotypes have been described : S. bobo, S. kua and S. farakan. As far as clinical problem is concerned, two main aspects are frequent : either typhoid fever syndrome (caused by S. typhi and, scarcely, by other germs, like S. dublin) or gastrointestinal infections, which present different forms and are more or less severe. Up to now, one single strain of S. typhi murium, suspected to be resistant to chloramphenicol has been isolated in 1977. Such a problem would need more complete research in a reference centre. Otherwise, no epidemic multiresistance has been observed. Checking strictly all the strains by systematic antibiograms is now absolutly essential in the plan of a steady epidemiological surveillance.

Adult↗
PubMedDate not supplied

[Culicidae of the French Territory of Afars and Issas. I. The genus Anopheles].

During an entomological survey conducted in French Territory of Afars and Issas from November 1973 to June 1975, eight Anopheles species were collected: A. rhodesiensis, A. azaniae, A. dthali, A. macmahoni, A. gambiae, A. turkhudi, A. salbaii and A. pharoensis. One can note particularly the presence of A. gambiae which does not seem to be observed in the Territory since the beginning of the century.

Africa↗
PubMedDate not supplied

[Culicidae of the French Territory of Afars and Issas. 2. The genus Culex].

During an entomological survey conducted in French Territory of Afars and Issas from November 1973 to June 1975, seven Culex species were collected: C. sitiens, C. tritaeniorhynchus, C. univittatus, C. simpsoni, C. laticinctus, C. pipiens fatigans, C. tenagius, to which we must add two other doubtfully identified species (C. ethiopicus and C. decens), and one unidentified species.

Africa↗