Prevalence of free living amoeba in the domestic waters reservoirs in Sfax, Tunisia.

Free living amoebas (FLA) are opportunistic pathogen found in different water sources in the environment. The aim of this study was to investigate the prevalence of free living amoeba in different samples of domestic water reserves (DWR) in Sfax region from Tunisia. It was a prospective study dealing with 486 water samples collected from different DWR. After filtration through a cellulose acetate membrane samples were cultured on non-nutrient agar and the FLA were detected and strained with Giesma, Trichrome and red nuclear stain for morphological and morphotypic studies. FLA were found in 62% of samples. The Acanthopodial morphotype was detected in 43%, Polytactic (38%), Monotactic (28%), Fan-shaped (17%), Rugose (11%), Dactilopodial (10%) and Eruptive (9%). These results demonstrate that domestic water reserves are a significant source of the FLA and maintenance of DWR is recommended.

Isolation and molecular identification of Acanthamoeba spp from oasis water in Tunisia.

In the southern Tunisia Oasis, we conducted 211 water with drawals from various water traffic sites. This water is used for agriculture, swimming or various other human activities. Acanthamoeba genus was detected in 82% of collected samples. Sequencing of the amplification products with primers P892C/P892 has allowed us to detect genotypic variation with predominance of T4 genotype (51%) and presence of the genotypes T14, T5, T3, T16, T15, T10, T11, T9 and T7. They T4, T3, T5, T15, T11 and T10 genotypes have a high potential for pathogenicity and a very high degree of virulence due to their production of serine proteases and extracellular cysteine enzymes involved in tissue degradation of the host. T4 genotype was the most abundant in the environment as well as in infections caused by Acanthamoeba spp. T5 genotype was ranked second and T3 genotype was less abundant in the environment and its pathogenicity is discussed. Acanthamoeba strains with the genotypes T16, T9 and T7 were considered non pathogenic. In fact, they have been isolated only from the environment. However, for these strains, their role as a reservoir can be a real risk to human health.

Comprehensive characterization and optoelectronic significance of Ho3+ and Cr3+ Co-doped ZnAl2O4 spinels.

The spinels ZnAl1.99-xHoxCr0.01O4 (with x = 0 and 0.001) were synthesized using a solid-state method, and various techniques were employed for their characterization. X-ray diffraction (XRD) analysis confirmed a cubic spinel structure with the Fd3̄m space group for both spinels. The morphology and homogeneity of the chemical composition were determined using scanning electron microscopy (SEM) and energy dispersive X-ray analysis. Raman and infrared vibrational spectroscopy techniques were also employed for analysis. The optical band gap (Eg) was determined from UV/vis absorption spectra, and the direct transition behavior was confirmed by Tauc's law. The observed large disorder and defect concentration are attributed to the presence of Cr3+ and Ho3+ ions, explaining this behavior. The electron paramagnetic resonance (EPR) measurement presented different types of traps. Room temperature absorption spectra exhibited multiple peaks corresponding to the 3d-3d and 4f-4f transitions of Cr3+ and Ho3+ ions. The results obtained validate the significance of our compounds in optoelectronic device applications.

Optical characterization and defect-induced behavior in ZnAl1.999Ho0.001O4 spinel: Unraveling novel insights into structure, morphology, and spectroscopic features.

The ZnAl1.999Ho0.001O4 phosphor, prepared by the solid-state method, crystallizes in the cubic spinel structure. Morphology and chemical composition homogeneity were determined via Energy Dispersive X-ray and SEM analysis. The (Eg) optical band gap was evaluated from the UV/vis absorption spectrum, confirming direct transition behavior according to Tauc's law. The Urbach energy (Eu) in the ZnAl1.999Ho0.001O4 spinel was higher than that in the ZnAl2O4 spinel, indicating increased disorder and a higher concentration of defects due to Ho3+ ions. The penetration depth (δ(λ)), optical extinction (k(λ)), and refractive index (n(λ)) were assessed across wavelengths (λ). The room temperature absorption spectrum revealed several peaks corresponding to the 4f-4f transitions of Ho3+ ions.

Summerfield scaling model and electrical conductivity study for understanding transport mechanisms of a Cr3+ substituted ZnAl2O4 ceramic.

Solid-state and sol-gel procedures were used to prepare ZnAl1.95Cr0.05O4 nanocrystal spinels. From the results obtained by X-ray diffraction (XRD) and transmission electron microscopy (TEM), it can be concluded that the samples prepared by sol-gel synthesis are better crystallized than the ones resulting from the solid-state method. Studies by spectroscopy of impedance were done in function of frequency (40-107 Hz) and temperature (540-680 K) in the sample prepared by sol-gel synthesis. The electrical conductivity spectra obey Jonscher's law and two models were observed studying the variation of the exponent 's' as a function of temperature, Correlated Barrier Hopping (CBH) and Non-overlapping Small Polaron Tunnelling (NSPT). The predominant conduction mechanism is bipolaron hopping. The scaling behavior of conductivity spectra was checked by Summerfield scaling laws. The time-temperature superposition principle (TTSP) points to a common transport mechanism working for the low and middle frequency ranges. The scaling mechanism fails in the high-frequency ranges suggesting that conduction dynamics, and the usual hopping distance of mobile species, have changed. The values obtained for the activation energy from the hopping frequency, conductivity σ dc, bulk resistance R gb, and relaxation (f max), in the temperature range of 540-680 K, are very close. A higher and negative temperature coefficient of resistivity (TCR coefficient) equal to -2.7% K-1 is found at 560 K. This result shows that our compound is suitable for uncooled infrared bolometric applications and infrared detectors.

A far-red-emitting ZnAl1.95Cr0.05O4 phosphor for plant growth LED applications.

ZnAl2-xCrxO4 (x = 0 and 0.05) samples were synthesized via a high-temperature solid-state reaction method. The structure, photoluminescence properties, EPR measurements, thermal stability, and chromaticity diagram of the far-red phosphor ZnAl1.95Cr0.05O4 were investigated. These measurements have enabled us to study the Cr3+ transitions and the site symmetry of Cr3+ in the ZnAl2O4 host lattice and examine the suitability of ZnAl1.95Cr0.05O4 for plant growth application. According to optical and EPR measurements, Cr3+ ions substitute Al3+ ions with D3d symmetry in the ZnAl2O4 host. PLE measurement indicates that upon excitation at 390 nm and 530 nm, the far-red phosphor ZnAl1.95Cr0.05O4 exhibited bright far-red emission around 687 nm. Photoluminescence phenomena show a sharp R line origin from the sublevels of the 2Eg(2G) → 4A2(4F) transition in Cr3+ ions. The 2Eg level was split into 2Eg (Eg) and 2Eg (2Ag) levels in the distorted crystal field environment, and the sharp R line in the ZnAl2O4 matrix was split into R1 and R2 lines. In this paper, the temperature-dependent luminescence characteristics of ZnAl1.95Cr0.05O4 have been investigated. As the temperature increased from 300 K to 440 K, a slight decrease in the intensity of the R1 and R2 lines was observed under excitation at 390 nm. The experimental results show that the ZnAl1.95Cr0.05O4 phosphors exhibit a nearly zero-thermal-quenching behavior. The CIE chromaticity coordinates of the ZnAl1.95Cr0.05O4 phosphor were located at the boundary of the chromaticity diagram, signifying that the phosphors possessed high color purity. The emissions of the ZnAl1.95Cr0.05O4 phosphor match well with the PFR absorption of phytochromes in plants. The investigation indicates that ZnAl1.95Cr0.05O4 is a potential far-red phosphor matching ultraviolet (UV) LED chips for plant growth applications.

[Associated factors and sub-clinical myocardial dysfunction in obese patients with masked hypertension]. / L'hypertension artérielle masquée chez les obèses : facteurs associés et atteinte myocardique infraclinique.

INTRODUCTION: Obesity is a worldwide health problem. Masked hypertension is a relatively recent reported entity with a diagnostic problem. The aim of this study was to determine the clinical and paraclinical characteristics and to identify the predictive factors of masked hypertension in obese patients. METHODS: It is a prospective study including obese patients with normal arterial pressure at office. All of these patients were given ambulatory blood pressure measurement (ABPM) to screen for masked hypertension, laboratory tests and a complete echocardiography study. RESULTS: A total of 50 patients were included. The mean age was 46.52±10.4 years. The mean systolic blood pressure (BP) at office was 120.8±8.8mmHg and the mean diastolic BP was 75±7.3mmHg. The prevalence of masked hypertension in obese adults was 36% with a predominantly non-dipper profile (38%). The study of echocardiographic parameters found dilated left atrium (LA) in 16 patients (32%). The left ventricle (LV) was hypertrophied in 32 patients (64%). The overall LV global longitudinal strain (GLS) was on average -18.85±0.9% and the LA GLS was on average 37.35±4.5%. In our study, metabolic syndrome, low HDL cholesterol, elevated fasting blood glucose, hyperuricemia, LA dilatation, LV hypertrophy, diastolic LV dysfunction and altered myocardial deformities were factors associated with masked hypertension in obese adults. CONCLUSION: It is important to screen for hypertension by ambulatory measurement in at-risk obese patients who present associated cardiovascular risk factors to reduce morbidity and mortality. Echocardiography and speckle tracking analysis could be helpful in detection sub-clinical myocardial deterioration in obese patients with masked hypertension.

[Impact of socioeconomic factors on blood pressure control: Observational study about 2887 hypertensive patients]. / Impact des facteurs socioéconomiques sur l'équilibre de la pression artérielle : étude observationnelle à propos de 2887 hypertendus.

INTRODUCTION: Despite therapeutic progress, less than half of hypertensive patients are controlled. The objective of this study was to examine the links between blood pressure control and socioeconomic factors. METHODS: We used data collected in the cardiology department of Sfax University Hospital as part of the Tunisian national hypertension registry. We studied the associations between the socio-economic variables (educational level, profession, medical insurance) and optimal blood pressure control (SBP<140mmHg and DBP<90mmHg) using logistic regression models. RESULTS: The average age of our population was 65 and the sex ratio was 0.95. We found, as expected, the clinical and behavioral factors associated with a good blood pressure control, namely: female sex, low-sodium diet, therapeutic compliance, and regular physical activity. However, obesity and an increased number of antihypertensive drugs have been associated with poor blood pressure control. The study of the effect of socio-economic variables on BP control finds a significant gradient against the most disadvantaged social categories for our three social variables in the univariate analysis. The inclusion of clinical and behavioral factors in the multivariate analysis attenuated these associations but did not fully explain them. CONCLUSION: Our study shows that there are social inequalities in the control of blood pressure. Social justice and improving living conditions are probably the real solutions to the problem of these social inequalities in health.

Subclinical left ventricle impairment following breast cancer radiotherapy: Is there an association between segmental doses and segmental strain dysfunction?

BACKGROUND: Cardiotoxicity following breast cancer radiotherapy (RT) represents one of the most redoubtable toxicities. The Global longitudinal strain measurement (GLS) based on 2D speckle tracking imaging (STI) allows detection of left ventricular (LV) dysfunction at a subclinical stage. The aim of this prospective study was to detect patients at risk of cardiotoxicity using echocardiographic parameters and to determine the association between segmental RT doses and early cardiac toxicity. MATERIAL AND METHODS: The STI was performed prior to RT and at 3, 6 and 12 months after. The association between subclinical LV dysfunction, defined as a reduction of GLS more than 10% from the initial value, radiation doses to different LV segments and non-radiation factors were performed based on multivariate analyses. RESULTS: From June 2017 to August 2018, a total of 103 female patients were included. Sixty patients had left sided RT. Seven patients (7.8%) developed a GSL impairment. The segmental alterations predominated in the anteroseptal and apical LV segments. The mean Dmean in altered segments was significantly higher than in non-altered segments (6.7 ± 8.8Gy-7.8 ± 8.9Gy vs 4.9 ± 7.9-5.4 ± 8.2Gy; p < 0.05). Age > 55 years and obesity were important confounding factors that should be considered during radiotherapy planning. CONCLUSION: The results of our study show that radiation dose is correlated with the subclinical LV segments' alteration. Global heart delineation seems to be insufficient during the breast radiotherapy planning. Segmental delineation of the LV may be an interesting alternative to limit segmental doses and to reduce the risk of subclinical alterations. A mean dose of 5Gy could be proposed in exposed heart segment.

A critical assessment of widely used techniques for nitrate source apportionment in arid and semi-arid regions.

The assessment of nitrate pollution origin using stable isotope techniques is a fundamental prerequisite for the application of sustainable groundwater management plans. Although nitrate pollution is a worldwide groundwater quality problem, existing knowledge on the origin of nitrate pollution in arid and semi-arid regions is still scarce. Using the example of the Grombalia aquifer (NE Tunisia), this work summarizes the main strengths and constraints of multi-isotope techniques targeting at nitrate source identification and apportionment The results highlighted that, even in the case of well-established methodologies, like those of isotope hydrogeochemistry (δ15NNO3, δ 18ONO3 and δ 11B) and mixing modelling for source apportionment, it is fundamental to take into account regional and local end-members to avoid biased data interpretation and to fully exploit the potential of such accurate tools.

Endovascular treatment of an immediate postoperative transplant renal artery stenosis with a polymer free drug eluting stent.

The transplant renal artery stenosis occurred up to 23% after kidney transplantation. Endovascular treatment has become the treatment of choice of this complication, but could be challenging in immediate postoperative anastomotic narrowing. We report the case of a adolescent with early renal graft artery stenosis located in the anastomosis and diagnosed 3 days after renal transplantation, with necessity of haemodialysis. This complication was treated by angioplasty on the 25th day, using a polymer free drug eluting stent with a good result. We discussed the precautions and technical features of this procedure.

The ongoing challenge of Pulmonary Tuberculosis in Southern Tunisia: A review of a 22-year period.

BACKGROUND: Despite the wide use of anti-tuberculosis drugs, pulmonary tuberculosis (PTB) remains one of the most important causes of mortality and morbidity, particularly in developing countries. Therefore, combining clinical and epidemiological approach would be of a great benefit. Our study aimed to describe the epidemiological and clinical specificities of PTB and its recent chronological trends. METHODS: We conducted a retrospective study of all PTB new cases of any age diagnosed between 1995 and 2016 in Southern Tunisia. We applied the direct method of age-standardization using the World Standard Population to compute the age standardized incidence rate (ASIR) and the age standardized mortality rate (ASMR) per 100 000 inhabitants. RESULTS: We recorded 1121 new cases with PTB among 2771 new cases of tuberculosis (40.5%). The ASIR of PTB was 5.3/100 000 inhabitants/year and didn't change over the study period (rho=0.3; P=0.2). Patients with PTB were mainly aged between 15 and 59 years (n=861; 76.8%) and came from urban areas (n=600; 55%). The median duration of treatment was 7.6 months (IQR=[6-8 months]). Successful outcome was notified in 1075 cases (95.9%). Forty-one patients died yielding an ASMR of 0.18/100 000 inhabitants/year. Factors statistically associated with unsuccessful outcome included age≥60 years (OR=5; P<0.001) and shorter treatment duration (6.15 months vs 7.76 months; P<0.001). CONCLUSION: In contrast to the decline in the global PTB incidence reported worldwide and in the neighboring countries, our study revealed no significant change in the PTB rates from 1995 to 2016. Therefore, tools and strategies used to manage PTB should be strengthened by a substantial effort in both basic science and epidemiology to have better incidence curves.

[Cardiac involvement in Steinert myotonic dystrophy]. / Les anomalies cardiaques au cours de la dystrophie myotonique de Steinert.

INTRODUCTION: Myotonic dystrophy type 1 (DM1) is an autosomal dominant multisystemic disease with frequent cardiac involvement that may cause sudden death. This study was performed to determine the various cardiac manifestations in DM1, their frequency and the relevance of cardiac electrophysiological study in this disease. METHODS: Ten patients with DM1, five men and five women, mean age 44.3+/-7.8 years underwent neurological and cardiac assessments. RESULTS: The most frequent electrocardiographic findings were conduction abnormalities, essentially by intraventricular conduction defects (eight out of ten cases) such as bundle branch or fascicular blocks. Echocardiography showed alterations in systolic left ventricular function in two cases. Invasive electrophysiology testing showed sub-hisien block in three patients, requiring cardiac pacemaker implantation. These three patients had normal duration of PR interval and normal width of QRS complex. CONCLUSIONS: We recommend that all patients with DM1 should undergo cardiac investigation to detect subclinical cardiac involvement.

[Microalbuminuria and left ventricular geometry in essential arterial hypertension]. / Microalbuminurie et geometrie ventriculaire gauche dans l'hypertension arterielle essentielle.

The association between left ventricular hypertrophy and microalbuminuria is actually admitted. Recent studies shown that patients with microalbuminuria have higher left ventricular mass index, worst systolic function and often concentric geometric kind of left ventricular hypertrophy. The efficiency of an adapted and early therapeutic on a potential relationship between reduction of microalbuminuria and improvement of target organ injury, principally heart and kidney, is still to evaluate. The aim of our study is to review geometric and hemodynamic aspect of left ventricular hypertrophy in hypertensive micro-albuminuria patients.

Prosthetic valve endocarditis: management strategies and prognosis: A ten-year analysis in a tertiary care centre in Tunisia.

BACKGROUND: Prosthetic valve endocarditis (PVE) is a rare and serious complication after heart valve replacement; its optimal management strategy, though, still needs to be defined. OBJECTIVE: To study the clinical, microbiological and echocardiographic characteristics of PVE and to analyse the influence of the adopted therapeutic strategy (medical or surgical) on short- and midterm outcome in a tertiary care centre in a developing country (Tunisia). METHODS: All cases of PVE treated in our institution between 1997 and 2006 were retrospectively analysed according to the modified DUKE criteria. RESULTS: A total of 48 PVE episodes were diagnosed (30 men and 18 women), mean age was 37.93 years. Twenty-eight patients (58.33%) were exclusively medically treated, whereas 20 (41.66%) were treated by a combined surgical and medical strategy. Indications for surgery were haemodynamic deterioration in eight patients (40%), annular abscess in six (30%) and persisting sepsis in six (30%). In comparison with those from the medical group, operated patients had a longer delay to diagnosis (p=0.025), were more frequently in heart failure (p=0.04) and experienced more early complications (p=0.011); they also more frequently had prosthetic dehiscence (p=0.015), annular abscesses (p=0.039) and vegetations >10 mm (p=0.008). Conversely, no differences were found between the groups in terms of age, sex, or nature of involved organisms. In-hospital mortality for the medical group was 14.28% and for the surgical group 35% (p=0.09). CONCLUSION: PVE is a very serious condition carrying high mortality rates regardless of the adopted strategy. Our study demonstrates that, in selected patients, medical treatment could be a successful and acceptable approach. (Neth Heart J 2009;17: 56-60.).

[Lung abscess: Diagnosis and management]. / Abcès du poumon : diagnostic et prise en charge.

Lung abscesses are necrotic cavitary lesions of the lung parenchyma. They are usually caused by anaerobic bacteria or mixed flora and typically occur after aspiration. Primary lung abscesses occur in previously healthy patients with no underlying medical disorders and are usually solitary. Secondary lung abscesses occur in patients with underlying or predisposing conditions and may be multiple. The initial diagnosis is usually made by chest radiography showing a lung cavity with an air-fluid level. Typically, the cavity wall is thick and irregular, and a surrounding pulmonary infiltrate is often present. The differential diagnosis of pulmonary cavitation is wide, including different types of possible infections, neoplasia and malformations of the bronchial tree. Management is usually based on prolonged antibiotic treatment. Failure of conservative management, manifested by the persistence of sepsis and/or other abscess complications, may necessitate drainage with invasive techniques (percutaneous, endoscopic or surgical) or open surgical removal of the lung lesion in patients with good performance status and sufficient respiratory reserve.

Orbital cellulitis secondary to a fungal sinusitis caused by Scopulariopsis: The first case in Tunisia.

We report a case of invasive fungal sinusitis caused by Scopulariopsis in 57 year-old man who had recurrence of orbital cellulitis. CT-scan and magnetic resonance imaging found an orbital cellulitis associated to a left frontal sinusitis with bone erosion and calcification. Patient was treated by surgical debridement and voriconazole. Culture of excised tissue was positive for Scopulariopsis.

[Results of percutaneous mitral balloon commissurotomy in pregnant women about 12 cases]. / Résultats de la dilatation mitrale percutanée chez la femme enceinte à propos de 12 cas.

INTRODUCTION: Mitral stenosis (MS) is the most common valvular heart disease revealed or exacerbated by pregnancy. Percutaneous mitral balloon commissurotomy (PMC) is currently the treatment of choice when mitral valve morphology is favorable. AIM OF THE STUDY: The purpose of this study is to evaluate the immediate, medium and long term results of percutaneous mitral balloon commissurotomy in pregnant women with a severe symptomatic mitral stenosis despite medical treatment. PATIENTS AND METHODS: It is a retrospective study including 12 pregnant patients diagnosed with severe mitral stenosis and hospitalized in the cardiology department of Habib Thameur hospital between 1994 and 2014. A clinical and ultrasonographic monitoring was performed for over 15 years. RESULTS: Mean patients age was 31.5±4.4 years. All patients were in NYHA class III or IV despite medical treatment. Mitral regurgitation was rated as moderate in four cases. Functional improvement was observed in all cases immediately after the procedure. Mitral valve area increased from 1.02±0.5cm2 averaged to 2±0.35cm2. Mitral regurgitation increased in three cases and appeared in two cases. All patients delivered at term. Newborns were all healthy. Two of them had a low birth weight. On the long term follow-up (95.58±64.1 months), five patients had mitral restenosis: two had a surgical valve replacement and three underwent a second percutaneous mitral balloon commissurotomy. CONCLUSION: The effectiveness of the percutaneous mitral balloon commissurotomy is clearly documented by clinical and echocardiographic evaluation. In the case of pregnancy, the goal is not so much to obtain an optimal result but to cause hemodynamic improvement authorizing the continuation of pregnancy and childbirth.