[Study of antigenic profile of blasts in acute lymphoblastic leukemia: flow cytometric analysis of 152 cases]. / Etude du profil antigénique des blastes au cours des leucémies aiguës lymphoblastiques : analyse de 152 cas par cytométrie en flux.

The aim of this study was to characterize the antigenic profile of blasts in acute lymphoblastic leukaemia (ALL) and to determine possible phenotypic aberrancies in a series of 152 patients with acute leukaemia diagnosed non myeloid leukaemia in cytology. Samples were analyzed by EPICS XL flow cytometer (Beckman Coulter) after staining with monoclonal antibodies(Beckman Coulter). Based on criteria of EGIL (European Group of Immunological Leukaemia), cases were classified as: acute lymphoblastic leukaemia (ALL, 52,6%); 75% cases of ALL belong to lymphoid B lineage. 80% of ALL B were CD10 positive, marker of best prognosis. In 10,5% of cases, biphenotypic leukaemia is diagnosed (lymphoid/myeloid). In 25% of cases aberrancies in phenotype were found. Flow cytometry has wide field of applications to characterize blast cells from patients with acute leukaemia: to establish diagnosis of lineage responsible in proliferation, to determine the stage of maturation, to predict prognosis for a better adaptation of adequate treatment, to follow evolution of disease after chemotherapy and to study minimal residual disease.

Design guidelines of 1-3 piezoelectric composites dedicated to ultrasound imaging transducers, based on frequency band-gap considerations.

Periodic piezoelectric composites are widely used for imaging applications such as biomedical imaging or nondestructive evaluation. In this paper such structures are considered as phononic crystals, and their properties are investigated with respect to periodicity. This approach is based on the investigation of band gaps, that strongly depend on the properties of the considered composites (geometry, size, nature of materials). It is motivated by the fact that band gaps in principle allow one to excite the thickness mode without exciting other parasitic propagating waves. The used plane-wave-expansion method has already been applied to periodic piezoelectric composites, but, in contrast to previous approaches, not only waves propagating in the symmetry plane of the composite are considered, but also waves propagating with a nonzero angle of incidence with this plane. The method is applied to a representative 1-3 connectivity piezocomposite in order to demonstrate its potentialities for design purposes. The evolution of band gaps is explored with respect to the wave vector component parallel to piezoelectric transducer-rod axis. All bulk waves that contribute to the setting up of plate modes in the vicinity of the thickness mode are found and identified.

Minimal residual disease detection in Tunisian B-acute lymphoblastic leukemia based on immunoglobulin gene rearrangements.

IGH gene rearrangement and IGK-Kde gene deletion can be used as molecular markers for the assessment of B lineage acute lymphoblastic leukemia (B-ALL). Minimal residual disease detected based on those markers is currently the most reliable prognosis factor in B-ALL. The aim of this study was to use clonal IGH/IGK-Kde gene rearrangements to confirm B-ALL diagnosis and to evaluate the treatment outcome of Tunisian leukemic patients by monitoring the minimal residual disease (MRD) after induction chemotherapy. Seventeen consecutive newly diagnosed B-ALL patients were investigated by multiplex PCR assay and real time quantitative PCR according to BIOMED 2 conditions. The vast majority of clonal VH-JH rearrangements included VH3 gene. For IGK deletion, clonal VK1f/6-Kde recombinations were mainly identified. These rearrangements were quantified to follow-up seven B-ALL after induction using patient-specific ASO. Four patients had an undetectable level of MRD with a sensitivity of up to 10-5. This molecular approach allowed identification of prognosis risk group and adequate therapeutic decision. The IGK-Kde and IGH gene rearrangements might be used for diagnosis and MRD monitoring of B-ALL, introduced for the first time in Tunisian laboratories.

Raman-like light scattering from acoustic phonons in photonic crystal fiber.

Raman and Brillouin scattering are normally quite distinct processes that take place when light is resonantly scattered by, respectively, optical and acoustic phonons. We show how few-GHz acoustic phonons acquire many of the same characteristics as optical phonons when they are tightly trapped, transversely and close to modal cut-off, inside the wavelength-scale core of an air-glass photonic crystal fiber (PCF). The result is an optical scattering effect that closely resembles Raman scattering, though at much lower frequencies. We use photoacoustic techniques to probe the effect experimentally and finite element modelling to explain the results. We also show by numerical modelling that the cladding structure supports two phononic band gaps that contribute to the confinement of sound in the core.

Identification of the translocation t(15;17) in acute myeloid leukemia (AML) initially classified as FAB M1: case report and review of the literature.

We report a case of a patient aged about 53 years, who initially presented with hematological disorders (WBC: 44000/mm3, Hb: 11g/dl, Pit: 127000/mm3) without tumoral syndrome. The Wright-Giemsa stained bone marrow and peripheral blood smears showed a population of blast cells characterized by cells with high N/C and strongly basophilic cytoplasm without granules. The nuclei were predominantly round. Nuclear chromatin was fine and contained small nucleoli. Cytochemisty was positive for peroxidase activity. Immunophenotyping showed myeloid typical markers of granulocytic lineage (MP0+, CD13+, CD33+, CD117+, CD34-). The karyotype revealed the expression of t(15;17) chromosomal translocation. The diagnosis of acute myeloid leukaemia (AML) was then evoked initially. The cytological features corresponded closely to the M1 subtype as defined in the FAB classification. The patient was treated with induction therapy according to the 7/3 protocol. One month later, he was discharged from hospital on hematological and cytogenetic remission. He died at home because of a heart attack. From the biological findings the patient was retrospectively diagnosed as having promyelocytic leukemia (hyperbasophilic form).

Evidence for complete surface wave band gap in a piezoelectric phononic crystal.

A complete surface acoustic wave band gap is found experimentally in a two-dimensional square-lattice piezoelectric phononic crystal etched in lithium niobate. Propagation in the phononic crystal is studied by direct generation and detection of surface waves using interdigital transducers. The complete band gap extends from 203 to 226 MHZ, in good agreement with theoretical predictions. Near the upper edge of the complete band gap, it is observed that radiation to the bulk of the substrate dominates. This observation is explained by introducing the concept of the sound line.

Complete band gaps in two-dimensional phononic crystal slabs.

The propagation of acoustic waves in a phononic crystal slab consisting of piezoelectric inclusions placed periodically in an isotropic host material is analyzed. Numerical examples are obtained for a square lattice of quartz cylinders embedded in an epoxy matrix. It is found that several complete band gaps with a variable bandwidth exist for elastic waves of any polarization and incidence. In addition to the filling fraction, it is found that a key parameter for the existence and the width of these complete band gaps is the ratio of the slab thickness, d, to the lattice period, a. Especially, we have explored how these absolute band gaps close up as the parameter d/a increases. Significantly, it is observed that the band gaps of a phononic crystal slab are distinct from those of bulk acoustic waves propagating in the plane of an infinite two-dimensional phononic crystal with the same composition. The band gaps of the slab are strongly affected by the presence of cutoff frequency modes that cannot be excited in infinite media.

[Haematological characteristics, FAB and WHO classification of 153 cases of myeloid acute leukaemia in Tunisia]. / Caractéristiques hématologiques et classification FAB et OMS de 153 cas de leucémies aiguës myéloïdes en Tunisie.

A complete blood analysis with a careful morphologic examination of peripheral blood and bone morrow smears completed by cytochemical reaction will help to classify the most acute myeloid leukaemia (AML). Actually, the study of other cytogenetis and immunophenotypic markers are now necessary to confirm diagnosis. The World Health Organisation WHO classification (2001) incorporates theses approaches. The purpose of this study is a bio-clinical review according to the WHO recommendations in 153 cases of LAM diagnosed between January 1998 and December 2003. The patients were aged 2 months to 90 years with sex ratio (M/F) of 1,22. The morphologic conclusion was difficult in 12% cases. Presence of dysplasia is noted in 50% of cases with multilineage dysplasia in 42% of cases. Our results showed cloned chromosomal abnormalities in 57% of cases (t(8;21): 12%, t(15;17) : 10%, Inv16: 1,3%, 11q23: 2,6% et complex karyotype: 14,3%). In 69% of cases with multilineage dysplasia, the karyotype was normal. 3 cases of LAM were noted at patients treated for breast cancer with chirurgic chemotherapy and radiotherapy 3, 4 et 5 years after treatment (LAM3 with t(15;17), LAM4 with genetic abnormalities of chromosomes 3, 5, 7, 8, 9, 14 et 16 et LAM 6 with genetic abnormalities of chromosomes 4, 7, 12, 14, 19 et 21). In WHO classification, cytology is essential in diagnosis of LAM even if the karytype have an important prognostic value. Research of signs of dysplasia lineage after lineage constitutes an important microscopic work and it is difficult to quantify dysplasia when the lineage is poor.

Familial hematological malignancies: ASXL1 gene investigation.

PURPOSE: Familial aggregation among patients with several hematological malignancies has been revealed. This emphasizes the importance of genetic factors. Only few genes predisposing to familial hematological malignancies have been reported until now due to the low occurrence. We have described in previous study PRF1 and CEBPA variants that might contribute to the background of genetic factors, which encourage us to extend our investigations to other cooperating genes. The aim of this study is to determine whether germline additional sex combs-like 1 (ASXL1) gene mutations may be involved? METHODS/PATIENTS: In this study, we investigated the candidate gene ASXL1 by direct sequencing in 88 unrelated Tunisian and French families with aggregated hematological malignancies. RESULTS: We report a new p.Arg402Gln germline missense substitution in two related Tunisian patients which has not been previously described. We identified here this variant for the first time in non-Hodgkin lymphoma. The p.Arg402Gln variant was not found in 200 control chromosomes. In silico analysis has predicted potential deleterious effect on ASXL1 protein. CONCLUSIONS: From an extended candidate genes analyzed in the field of familial hematological malignancies, ASXL1 might be involved. This variant should be considered since a potential damaging effect was predicted by in silico analysis, with a view to develop functional assay in order to investigate the biological assessment.

Hydatid cyst of the right atrium and rheumatic mitral disease: a fortuitous association.

Ecchinococcal infestation of the heart accounts for only 0.5-2% of ecchinococcosis cases. A case is reported of right atrial hydatid cyst associated with rheumatic mitral valve disease in a 43-year-old woman. Physical examination and chest X-radiography revealed mitral disease. Transthoracic and transesophageal echocardiography demonstrated a single, large cystic mass of 4 x 4 cm located in the right atrium, and heavily calcified mitral rheumatic disease with commissural fusion. Confirmatory computed tomography and magnetic resonance imaging excluded other extracardiac locations. Radioisotopic lung perfusion scanning and angiographic scanning excluded pulmonary embolism. The patient underwent mitral valve replacement and the hydatid cyst was excised. An intraoperative examination and subsequent pathology confirmed a diagnosis of hydatid cyst.

Out-of-plane propagation of elastic waves in two-dimensional phononic band-gap materials.

We have used a plane-wave-expansion model to study the out-of-plane propagation of elastic waves in a two-dimensional phononic band-gap material. The case of quartz rods embedded in an epoxy matrix has been computed. Band gaps for nonzero values of the wave-vector component parallel to the rods are shown to exist and are investigated. For wavelengths smaller than the period of the structure, modes are found that are localized in the epoxy intersites, and propagate perpendicularly to the plane of the structure.

Guided elastic waves along a rod defect of a two-dimensional phononic crystal.

It was shown that elastic waves propagating out-of-plane in a two-dimensional phononic crystal can experience full-band-gaps for nonzero values of the wave-vector component parallel to the rods. By further inserting a rod defect, it is demonstrated that modes propagating along the rod defect can be localized within the band-gaps of the phononic crystal. Such waveguide modes are exhibited for a tungsten/epoxy composite containing an aluminum nitride rod as the rod defect. It is expected that guided modes of such a structure can be excited and detected electrically owing to the piezoelectric effect.

Tunable filtering and demultiplexing in phononic crystals with hollow cylinders.

Acoustic band gap (ABG) materials constituted of steel hollow cylinders immersed in water can exhibit a tunable narrow pass band (NPB) located inside their gap. We theoretically investigate, using the finite difference time domain (FDTD) method, the properties of waveguides composed of a row of hollow cylinders in a two-dimensional (2D) phononic crystal made of filled steel cylinders. These waveguides exhibit NPB's at frequencies slightly higher than their infinite periodic ABG counterpart. The frequency of the waveguide's NPB can be selected by adjusting the inner radius of the hollow cylinders or by changing the nature of the fluid that fills them. We show that a waveguide constituted of a row of hollow cylinders with different inner radii can transport waves at two different frequencies. By selectively filling the cylinders with water or mercury we have created an active device that permits the transmission of waves at one, both, or neither of these frequencies. Finally, we examine the multiplexing and demultiplexing capabilities of Y shaped waveguides constituted of hollow cylinders.

Stopping of acoustic waves by sonic polymer-fluid composites.

A two-dimensional periodic array of air cylinders in water is known to have giant acoustic stop bands [M.S. Kushwaha and B. Djafari-Rouhani, J. Appl. Phys. 84 (1998) 4677]. It is shown in the present paper that hollow cylinders made of an elastically-soft polymer containing air inside and arranged on a square lattice in water can still give rise to large acoustic band gaps. Similar properties can also be obtained with a close-packed array of tubes containing water when arranged on a honeycomb lattice in air. The transmission coefficient of films made of such polymer-fluid composites has been calculated by finite difference time domain method. With film thickness not exceeding 75 mm, a deep sonic attenuation band was found with, in the best cases, a lower limit below 1 kHz and an upper limit above 10 kHz.

Theory of acoustic scattering by supported ridges at a solid-liquid interface.

We combine a general Green's function formalism and an approach due to Nyborg [W. L. Nyborg, in Acoustic Streaming, Physical Acoustics, edited by W. P. Mason (Academic, London, 1965), Vol. II B, Chap. 11] to calculate the first-order pressure and second-order pressure gradient fields in the vicinity of solid inhomogeneities at a solid/liquid interface. We treat the problem of scattering of an incident acoustic plane wave by a single ridge and two parallel ridges separated by a trench on a planar substrate. The calculated vibrational density of states shows the existence of resonances at low frequencies, especially in the case of a trench. Excitation of a trench resonant vibrational mode enhances the magnitude of the first-order pressure and of the second-order pressure gradient. The resonant frequencies of a trench decrease and the pressure enhancement increases with increasing aspect ratio of the ridges (height to width).

Phononic crystal with low filling fraction and absolute acoustic band gap in the audible frequency range: a theoretical and experimental study.

The propagation of acoustic waves in a two-dimensional composite medium constituted of a square array of parallel copper cylinders in air is investigated both theoretically and experimentally. The band structure is calculated with the plane wave expansion (PWE) method by imposing the condition of elastic rigidity to the solid inclusions. The PWE results are then compared to the transmission coefficients computed with the finite difference time domain (FDTD) method for finite thickness composite samples. In the low frequency regime, the band structure calculations agree with the FDTD results indicating that the assumption of infinitely rigid inclusion retains the validity of the PWE results to this frequency domain. These calculations predict that this composite material possesses a large absolute forbidden band in the domain of the audible frequencies. The FDTD spectra reveal also that hollow and filled cylinders produce very similar sound transmission suggesting the possibility of realizing light, effective sonic insulators. Experimental measurements show that the transmission through an array of hollow Cu cylinders drops to noise level throughout frequency interval in good agreement with the calculated forbidden band.

[Screening of hemoglobinopathies and molecular analysis of beta-thalassemia in Central Tunisia]. / Dépistage des hémoglobinopathies et analyse moléculaire des beta-thalassémies en Tunisie centrale.

BACKGROUND: Previous investigations have permitted to locate 16 beta-thalassemic mutations in different samples of the Tunisian population. One of them (IVS I nt 2: T--G) had been found only in the central region of Tunisia. Our research was carried out in this part of the country to estimate the prevalence of this mutation and to establish a prenatal diagnosis using appropriate probes. POPULATION AND METHODS: One thousand one hundred and five blood samples taken from 1987 to 1990 from healthy blood donors and 346 samples taken from 1985 to 1992 from patients were analysed. Detection of hemoglobinopathies was carried out by means of specific hematological tests and different electrophoretic and chromatographic techniques. Mutations were detected by means of the usual techniques of molecular biology. RESULTS: Sickle cell anemia and beta-thalassemia were the most frequent in the samples studied. The molecular analysis carried out on eight patients native of the Essouassi-El-Djem region point out that all these patients carry the same point mutation (IVS I nt 2: T-G) detected for the first time in 1988 in a patient native of the same region. One of these patients, aged 43, who did not suffer from anemia and did not show the usual symptoms of beta O thalassemia, had one hemolytic attack at the age of 17. CONCLUSIONS: The high number of persons carrying Hb S and beta-thalassemia trait increase the risk of appearance of homozygous forms. The presence of the same mutation IVS I nt 2: (T-G) in all beta O-thalassemic patients from Essouassi-El Djem region may indicate that it may have its origin there. The heterogeneity of clinical phenotype of these patients shows the difficulty of establishing a unique strategy of prenatal diagnosis by DNA analysing which can be applied in all cases.

[Infantile visceral leishmaniasis: difficult diagnosis in cases complicated by hemophagocytosis]. / Leishmaniose viscérale infantile: un diagnostic difficile en cas d'hémophagocytose associée.

BACKGROUND: Hemophagocytosis has already been reported in cases of visceral leishmaniasis and thus may complicate search for diagnosis. CASE REPORT: A previously healthy 2 year-old boy was referred for fever and splenomegaly with pancytopenia. An initial diagnosis of kala-azar was refuted because of absence of biological inflammatory syndrome, negativity of bone-marrow aspiration and splenic ponction and of specific serology. After three months of clinical deterioration and apparition of active hemophagocytosis, both bone marrow aspiration and specific serology for visceral leishmaniasis became positive. The boy was given sodium stibogluconate for 20 days; he improved gradually with complete and definitive remission. CONCLUSION: Diagnosis of visceral leishmaniasis may be difficult, even in countries where this condition is relatively frequent; the association with hemophagocytosis is possible and does not constitute a poor factor of prognosis if specific therapy is proposed.