Biomedical subjects

M Abaza

Publications and source records attributed to M Abaza.

7 recordsLinked to original sources

PubMed2000

Treatment of stenosis and thrombosis in haemodialysis fistulas and grafts by interventional radiology.

BACKGROUND: There are no large series reporting the long-term results after radiological treatment of both stenosis and thrombosis in native fistulas (AVFs) and prosthetic grafts. METHODS: Between 1987 and 1999, 726 dilations, 135 stent placements and 257 declotting procedures were performed in 209 consecutive forearm AVFs, 74 upper arm AVFs and 156 prosthetic grafts. The stents used were the Wallstent*, the Craggstent*, and the Passager*. Declotting was performed by manual catheter-directed thromboaspiration, with or without previous urokinase infusion. RESULTS: The initial success rates ranged from 78 to 98%. The rate of significant complications was 2%. Primary patency rates at 1 year were twice as good for forearm AVFs (50%) than for grafts (25%) (P<0.05), and were 34% for upper arm AVFs. Secondary patency rates were similar in the 3 groups at 1 year (80-86%) and at 2 years (68-80%). Reintervention was necessary every 18 months in forearm AVFs compared to every 9 months in grafts (P<0.05). Thrombosed grafts fared worse than failing grafts. Accesses of less than 1 year's duration needed more reinterventions than older accesses (every 16 months versus 30 in forearm AVFs, every 7 months versus 13 in grafts, P<0.05). CONCLUSIONS: The percutaneous treatment of stenosis and thrombosis in haemodialysis access achieves patency rates similar to those reported in the surgical literature and confirms that grafts must be avoided as much as possible given their poorer outcome, especially after the first thrombosis. Poorer outcome is also demonstrated in accesses of less than 1 year's duration.

Arm↗

PubMed1993

Acute biphenotypic leukaemia: immunophenotypic and cytogenetic analysis.

The incidence of acute biphenotypic leukaemia has ranged from less than 1% to almost 50% in various reports in the literature. This wide variability may be attributed to a number of reasons including lack of consistent diagnostic criteria, use of various panels of antibodies, and the failure to recognize the lack of lineage specificity of some of the antibodies used. The morphology, cytochemistry, immunophenotype and cytogenetics of acute biphenotypic leukaemias from our institution were studied. The diagnostic criteria took into consideration the morphology of the analysed cells, light scatter characteristics, and evaluation of antibody fluorescence histograms in determining whether the aberrant marker expression was arising from leukaemic blasts or differentiated bone marrow elements. Fifty-two of 746 cases (7%) fulfilled our criteria for acute biphenotypic leukaemias. These included 30 cases of acute lymphoblastic leukaemia (ALL) expressing myeloid antigens, 21 cases of acute myelogenous leukaemia (AML) expressing lymphoid markers, and one case of ALL expressing both B- and T-cell associated antigens. The acute biphenotypic leukaemia cases consisted of four major immunophenotypic subgroups: CD2+ AML (11), CD19+ AML (8), CD13 and/or CD33+ ALL (24), CD11b+ ALL (5) and others (4). Chromosomal analysis was carried out in 42/52 of the acute biphenotypic leukaemia cases; a clonal abnormality was found in 31 of these 42 cases. This study highlights the problems encountered in the diagnosis of acute biphenotypic leukaemia, some of which may be responsible for the wide variation in the reported incidence of this leukaemia. We suggest that the use of strict, uniform diagnostic criteria may help in establishing a more consistent approach towards diagnosis of this leukaemic entity. We also suggest that biphenotypic leukaemia is comprised of biologically different groups of leukaemia based on immunophenotypic and cytogenetic findings.

Adolescent↗

PubMed1993

Insufficient dialysis shunts: improved long-term patency rates with close hemodynamic monitoring, repeated percutaneous balloon angioplasty, and stent placement.

Over 54 months, 70 short stenoses of 63 shunts (32 Brescia-Cimino fistulas, 31 grafts) in 59 patients necessitated a first percutaneous transluminal angioplasty (PTA). Restenosis led to 63 redilations in 38 lesions. Nine stents were inserted in seven grafts and two proximal veins in seven patients, the indication being that stenosis had recurred twice in 6 months. In three of these stenoses, five delayed intrastent redilations were necessary. Three previously dilated occluded grafts were recovered with local thrombolysis. Morbidity was 4.08%, with one immediate rupture, four delayed pseudoaneurysms (1-28 months), and two periprocedural bacteremias. Half (15 of 29) of graft stenoses and only 14% (four of 27) of Brescia-Cimino fistula stenoses had a mean restenosis interval of less than 6 months. The mean restenosis interval increased from 3.6 months +/- 0.5 (standard deviation) before stent placement to 15.2 months +/- 0.4 after stent placement (P < .001). Insertion of a stent can be advised when stenoses of graft venous anastomoses have recurred twice in less than 6 months. The combination of all interventional radiologic procedures allowed a significant improvement in secondary patency rates after PTA, with 82% at 1 year, 79% at 2 years, and 71% at 3 years.

Adult↗

PubMed1993

Studies on human fascioliasis in Egypt. 2. Serum iron and copper in chronic fascioliasis.

Twenty-three patients diagnosed as established fascioliasis were enrolled in the present study. Fasciolia cases were investigated for serum iron, copper and their carrier proteins together with haemoglobin and some blood indices. A significant reduction in serum iron was detected in the examined group. This reveals the occurrence of iron deficiency anaemia in patients with chronic fascioliasis.

Adolescent↗

PubMed1992

Effects of timing and dose of vitamin A on tissue retinol concentrations and antibody production in the previously vitamin A-depleted rats.

The effect of retinol repletion in previously vitamin A-depleted Lewis rats on antibody production to pneumococcal polysaccharide (SSS-III) was studied. When vitamin A-depleted rats were given either 0.35 mumol (0.1 mg) or 5.2 mumol (1.5 mg) retinol, plasma retinol became normal within 8 h. Liver and lymphoid-organ retinol concentrations were normalized by 1 d after repletion with 5.2 mumol but not 0.35 mumol retinol. Antibody production to SSS-III was compared after administering 5.2 mumol retinol either as a divided dose (half given 4 d before and half given on the day of immunization) or as a single dose concurrent with immunization. Vitamin A-depleted rats produced very little SSS-III-specific antibody. The divided dose of retinol consistently restored anti-SSS-III production whereas the single concurrent dose was less effective despite equal effects on tissue retinol concentrations. Interestingly, normalization of plasma retinol was not always a good predictor of the immune response to pneumococcal polysaccharide.

Animals↗

PubMed1991

Imaging cytometry by multiparameter fluorescence.

A system is described for performing multicolor fluorescence image cytometry of cell preparations. After the setting up stage, the operation is automatic: the microscope fields are found and focused; then images are acquired for each fluorophore, corrected and analyzed, without any operator interaction. Human peripheral blood lymphocytes on microscope slides were used as a test system. In these experiments, three fluorescent antibodies were used to identify lymphocyte sub-populations, and a DNA content probe was used to identify all nucleated cells. The cell subset percentages determined by image cytometry were comparable to percentages obtained when cells from the same preparation were analyzed by flow cytometry. Multicolor fluorescence imaging cytometry can potentially be extended to the analysis of cells in smears, fine needle biopsies, imprints, and tissue sections.

Algorithms↗

PubMedDate not supplied

Wallstents and Craggstents in hemodialysis grafts and fistulas: results for selective indications.

PURPOSE: To report the value of selective placement of self-expandable stents (Wallstent and Craggstent) for the treatment of limitations and, occasionally, of complications of dilation in hemodialysis access, and especially for delaying restenosis. MATERIALS AND METHODS: This is a retrospective study of a 7-year period, during which 41 Wallstents and 11 Craggstents were placed in 26 polytetrafluoroethylene (PTFE) grafts, 15 native fistulas, and nine central veins of 47 patients. The indications were stenosis recoil (n = 13), recurrent restenosis within 6 months (n = 33), restenosis after 6 months (n = 3), and acute angioplasty-induced rupture (n = 1). Restenosis after stent placement necessitated redilation and percutaneous declotting and 10 additional stent placements. RESULTS: Two initial misplacements were corrected immediately. Primary patency rates for PTFE grafts were 58% +/- 10% at 6 months and 23% +/- 10% at 1 year, respectively. Secondary patency rates were 100% at 6 months and 88% +/- 8% at 1 year, respectively. For native fistulas, primary patency rates were 47% +/- 12% at 6 months and 20% +/- 18% at 1 year. Secondary patency rates were 95% +/- 6% at 6 months and 79% +/- 14% at 1 year. It was necessary to reintervene after stent placement to maintain or to restore patency every 9 months for PTFE grafts and every 7.3 months for native fistulas. When stents were placed for treatment of early recurring restenosis, the mean interval between radiologic interventions (redilations or declottings) performed to maintain or to restore patency before stent placement was multiplied by 2.1 after stent placement for both grafts (3.2 months increased to 6.9, P < .01) and native fistulas (2.9 months increased to 6.2, P < .02). CONCLUSIONS: Wallstents and Craggstents are valuable for the treatment of failure of regular dilation and they double the intervals between reinterventions for early (< 6 months) recurring stenoses in PTFE grafts and native fistulas.

Adult↗