Fathia Zghal

Ecology and distribution of the freshwater planarian Schmidtea mediterranea in Tunisia

Abstract The ecology of Schmidtea mediterranea, a freshwater planarian, is here described for the first time from Tunisia. The population consists of sexual diploids with a chromosome number of 2n = 8, and reproduces exclusively sexually through the formation of cocoons. Seasonal variation in the number of animals present as well their state of maturity, were correlated with water temperature.

The freshwater planarian Dugesia sicula Lepori, 1948 (Platyhelminthes, Tricladida) in Tunisia: ecology, karyology, and morphology

A study was carried out on freshwater planarians of the genus Dugesia from three localities in northern Tunisia: Joumine, Chiba, and Lebna. The three populations are fissiparous under field conditions and do not possess reproductive organs, except for some cases of hyperplastic ovaries in the Joumine population. After five months of breeding under laboratory conditions, with water temparature between 18 and 25 °C and under short photoperiod, 8.33 to 26% of specimens from the Joumine stream became sexualized, together with considerable increase of body length and width. For the other two populations the sexualization rate was very small. Extended period of darkness apparently played a positive role in this sexualization. The phenomenon of sexualization is discussed in the context of reproductive strategies. Histological and karyological studies of the sexualized animals allowed identification of these usually fissiparous planarians as representatives of Dugesia sicula Lepori, 1948. The species is here reported for the first time from Tunisia. The populations are restricted to permanent water basins resulting from the construction of dams in large rivers.

Étude ultrastructurale de l’ovogenèse chez la planaire Schmidtea mediterranea (Plathelminthe, Paludicole)

The ovary of the freshwater planarian Schmidtea mediterranea has been studied for the first time using both light and electron microscopy methods. The ultrastructure of the ovary revealed two types of cells: accessory cells and germinal cells at various stages of differentiation, distributed along a maturation axis. Initially, oogonia underwent cytoplasm growth due to the development of organelles, such as endoplasmic reticulum, Golgi complex, and mitochondria, which are all involved in the production of cytoplasmic inclusions or yolk globules. It is shown that the chromatoid body and fibrogranular aggregates may participate in the synthesis of vitelline inclusions. When completely mature, the oocytes have become larger, due to the accumulation of nutritive inclusions, which are round in shape and have a paracrystalline structure. These inclusions are interpreted as being yolk globules and may represent a kind of nutritive material for the developing embryo. These ultrastructural features of the ovary agree with the available phylogenetic tree, based on morphological and karyological characters that considers Schmidtea group as a genus and not a subgenus. The presence of sperm between the oocytes suggests that fertilization may occur within the ovary, representing an uncommon condition within the Triclads, in which fertilization usually takes places outside of the ovaries.

Sperm transfer and fertilization in the marine planarian Sabussowia dioica (Platyhelminthes, Tricladida, Maricola)

Summary It has been established that in the gonochoristic marine planarian Sabussowia dioica (Claparede, 1863), the male animal produces sclerotic spermatophores that are deposited onto the body wall of the female. Sperm contained in these capsules penetrate the parenchyma and eventually enter the ovaries and the anterior vitellarian follicles. External deposition of spermatophores is unique within the triclads, while formation of spermatophores is unique within the marine planarians.

Cocoon production, deposition, hatching, and embryonic development in the marine planarian Sabussowia dioica (Platyhelminthes, Tricladida, Maricola)

Summary Cocoons and embryonic development of the dioecious marine planarian Sabussowia dioica are described for the first time. Characteristics of cocoon production, deposition, hatching time, number of hatchlings, and embryonic development are compared with data reported in the literature for other triclads.

Recurrent Fulminant Myocarditis Revealing a Pheochromocytoma

Introduction: Pheochromocytoma is a rare etiology of fulminant myocarditis. It is however a curable tumor in which surgical ablation spares patients from dreadful cardiac complications surgical ablation spares patients from dreadful cardiac complications. Case report: We report the case of a 61-year-old patient, with a pheochromocytoma, documented by pathologic examination and revealed by recurrent fulminant myocarditis. Conclusion: It is advisable to search for pheochromocytoma in case of a non-explained and a fortiori recurrent myocarditis. Given its curability, potentially fatal complications could possibly be avoided after surgical treatment.

0511: Intraventricular delay and cardiac dysfunction in patients with myocardial infarction

In the acute phase of myocardial infarction (AMI), ischemic phenomena may affect the strength and timing of myocardial contraction. Purpose To correlate intraventricular delays to systolic, diastolic and performance parameters of the left ventricle (LV) and to heart failure occurrence in AMI patients. Methods A total of 372 consecutive patients (mean age: 61.6±12.4 years) who presented with an AMI were prospectively enrolled. Echocardiographic evaluation was carried out within 24-36 hours. Six basal LV segments were explored by pulsed tissue Doppler imaging (TDI) for electromechanical delays. Intraventricular mechanical delay (IMD) was then calculated from the difference between the earliest and most delayed sites. Correlations were assessed by the nonparametric Spearman rho test, and means were compared using Kruskall-Wallis and Mann-Whitney tests were used for correlations and Results The IMD (30.3ms±13.72ms) was not correlated to the location and extent of the AMI. The IMD was correlated to the cardiac output (Rho=-0.27, p=0.003) and to the mitral annular systolic velocity (lateral: Rho=0.18, p=0.027 and septal: Rho=-0.37, p 42.5ms had a higher rate of in-hospital heart failure (35.0% versus 4.7%, p Conclusion acute dyssynchrony in patients with AMI could be a marker or a factor of cardiac dysfunction.

121: Left ventricular diastolic function evaluation by left atrial volume and myocardial performance index in patients with acute myocardial infarction

Background Both left atrial volume index (LAVI) and myocardial performance index (MPI) were proved to be reliable parameters of left ventricular (LV) diastolic function. Aim We aimed to assess their usefulness in the setting of acute myocardial infarction (AMI) in comparison with conventional diastolic parameters Methods A cohort of three hundred and sixty patients with AMI (72% with ST segment elevation) with a mean age of 61.6 ±12.4 years (79% males; 39% diabetics) was enrolled. Patients with atrial fibrillation or conduction abnormalities were excluded from the study. All patients had a conventional and Doppler echocardiography assessment 24 to 36 hours after admission coupled with a measurement of LAVI and MPI index by conventional Doppler method (MPI1), tissue Doppler method at the lateral side of the mitral annulus (MPI2) and at its medial side (MPI3). Correlation between parameters was evaluated by Pearson coefficient (r). Results The three MPI indexes were significantly correlated to these parameters of LV diastolic function: The early diastolic tissue velocities at the lateral side of the mitral annulus (Ea l) (r1=−0.31, r2=−0.36, r3=−0.46, p LVAI was not correlated to MPI (r1=0.14, r2=0.11, r3=0.11, p>0.05) and it was only correlated with the early diastolic tissue velocity at the medial side of the mitral annulus (Ea s) (r=−0.18, p Conclusion While myocardial performance conventional and tissue indexes are strongly correlated with diastolic LV function in the acute phase of myocardial infarction, left atrial volume index seems be not sensitive to acute but only chronic alterations of this function.