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Biomedical subjects

M Alami

Publications and source records attributed to M Alami.

52 records · Page 3Linked to original sources
PubMed1999

[Chronic urine retention disclosing isolated spinal dermoid cyst].

Spinal dermoid cysts are congenital lesions. Neurological symptoms are related to the affected area of the vertebral canal. The commonest type involves the sacrococcygeal area. Lesions of the cauda equina are found which result in sciatic pain, paresis of the bladder and rectum, flaccid paresis of the legs, and/or sphincter disturbances. The histology is typical and benign. The images on CT and MR provide diagnosis. We report a case of spinal dermoid cyst revealed by chronic urinary retention.

Adolescent↗
PubMed1998

Involvement of ATP-dependent Pseudomonas exotoxin translocation from a late recycling compartment in lymphocyte intoxication procedure.

Pseudomonas exotoxin (PE) is a cytotoxin which, after endocytosis, is delivered to the cytosol where it inactivates protein synthesis. Using diaminobenzidine cytochemistry, we found over 94% of internalized PE in transferrin (Tf) -positive endosomes of lymphocytes. When PE translocation was examined in a cell-free assay using purified endocytic vesicles, more than 40% of endosomal 125I-labeled PE was transported after 2 h at 37 degrees C, whereas a toxin inactivated by point mutation in its translocation domain was not translocated. Sorting of endosomes did not allow cell-free PE translocation, whereas active PE transmembrane transport was observed after > 10 min of endocytosis when PE and fluorescent-Tf were localized by confocal immunofluorescence microscopy within a rab5-positive and rab4- and rab7-negative recycling compartment in the pericentriolar region of the cell. Accordingly, when PE delivery to this structure was inhibited using a 20 degrees C endocytosis temperature, subsequent translocation from purified endosomes was impaired. Translocation was also inhibited when endosomes were obtained from cells labeled with PE in the presence of brefeldin A, which caused fusion of translocation-competent recycling endosomes with translocation-incompetent sorting elements. No PE processing was observed in lymphocyte endosomes, the full-sized toxin was translocated and recovered in an enzymatically active form. ATP hydrolysis was found to directly provide the energy required for PE translocation. Inhibitors of endosome acidification (weak bases, protonophores, or bafilomycin A1) when added to the assay did not significantly affect 125I-labeled PE translocation, demonstrating that this transport is independent of the endosome-cytosol pH gradient. Nevertheless, when 125I-labeled PE endocytosis was performed in the presence of one of these molecules, translocation from endosomes was strongly inhibited, indicating that exposure to acidic pH is a prerequisite for PE membrane traversal. When applied during endocytosis, treatments that protect cells against PE intoxication (low temperatures, inhibitors of endosome acidification, and brefeldin A) impaired 125I-labeled PE translocation from purified endosomes. We conclude that PE translocation from a late receptor recycling compartment is implicated in the lymphocyte intoxication procedure.

ADP Ribose Transferases↗
PubMed1998

[Syphilitic aortitis and "accelerated" atherosclerosis].

The authors present the case of a 42 year old patient admitted for surgery of massive aortic regurgitation. Investigation of this patient who had no significant cardiovascular risk factors, showed diffuse and accelerated atherosclerosis (severe stenosis at the origin of both subclavian arteries at both superficial femoral arteries). Tertiary syphilis with neurological involvement and aortitis was confirmed by histological examination (peroperative biopsy of the aortic wall). This case is unusual due to the association of early atherosclerosis with tertiary syphilis and raises the question of the causality of syphilis in the generation of these atherosclerotic lesions.

Adult↗
PubMed1998

[Percutaneous transluminal valvuloplasty in congenital pulmonary stenosis in adults. Apropos of 34 cases].

Percutaneous pulmonary valvulotomy is the treatment of choice for isolated congenital pulmonary valvular stenosis in childhood. However, experience of this procedure in the adult is much more limited. Between January 1984 and December 1994, 34 patients with severe or moderate pulmonary valvular stenosis underwent percutaneous transluminal valvuloplasty. The age of the patients ranged from 20 to 47 years (mean 22 +/- 4 years). Cardiac catheterisation was performed using the femoral vein in 27 cases and the internal jugular vein in 7 cases. Success was obtained in 28 patients (81% of cases). Pulmonary artery-right ventricular pressure gradient decreased from 113 +/- 35 to 32 +/- 13 mmHg (p < 0.001) after valvuloplasty with one or two balloon catheters. The tolerance of transluminal valvuloplasty was generally good. The poor results were explained by cases of dysplasic valves or of infundibular reactions. There was one death which occurred 24 hours after the procedure. Clinical and echocardiographic follow-up was obtained in 20 patients, 3 to 36 months after valvuloplasty (average: 23 +/- 13 months). No cases of restenosis were observed. Percutaneous transluminal pulmonary valvuloplasty in the adult is feasible and gives good results which are maintained at medium-term; it has become the treatment of choice of valvular pulmonary stenosis and gives good results which are maintained at medium-term, thereby avoiding surgical valvulotomy.

Adult↗
PubMed1998

[Epidemiology of sinusitis seen in hospitalized patients. Apropos of 77 episodes of sinusitis among 72 patients between 1993 and 1996].

The 77 cases of sinusitis seen in 72 patients admitted to the Briançon Hospital between January 1, 1993, and June 30, 1996, were studied. One or both maxillary sinuses were involved in 96.8% of cases. Sinus aspiration was done in 95 cases. All aspirates were subjected to microbiological studies. Of the 45 aspirates that yielded positive cultures, 36 grew one or more pathogenic organisms. The most commonly isolated bacteria were Pseudomonas aeruginosa (n = 7), Streptococcus pneumoniae (n = 5), and Haemophilus influenzae (n = 5). Nosocomial sinusitis defined on a set of criteria including hospital stay duration at onset and an acute tempo of evolution contributed 32.5% of cases overall, 55.2% in the intensive care unit and 18.7% in all other departments combined. Nosocomial cases in the intensive care unit were associated with well-known risk factors, namely tracheal intubation with ventilation and presence of a nasogastric tube. Other study criteria included the type of organism recovered by culture and whether patients ventilated via a tracheal tube had the same organism in their sinus and tracheal tube aspirates. Some nonintensive care patients had none of the known risk factors for sinusitis; prompt diagnosis and treatment of these cases of sinusitis is important to avoid infectious complications, which are, however, less common than in intensive care patients.

Adolescent↗
PubMed1997

Correlation of thallium uptake with left ventricular wall thickness by cine magnetic resonance imaging in patients with acute and healed myocardial infarcts.

Myocardial infarction (MI) is characterized by cellular necrosis which undergoes fibrotic transformation over time. Cine magnetic resonance imaging (MRI) offers high-resolution 3-dimensional images of the left ventricular myocardium, allowing sampling of the myocardial wall thickness over the entire left ventricle. Tomographic (single-photon emission computed tomography [SPECT]) thallium images also provide 3-dimensional information on the location and level of thallium uptake, which has been shown to correlate with myocardial viability. The purposes of this study were: (1) to examine the relation between both end-diastolic and end-systolic wall thickness and normalized thallium-201 uptake over the left ventricle in a group of patients with MI, (2) to examine the relation between regional wall thickening and normalized thallium uptake, and (3) to examine the relation between thallium uptake and wall thickness both early and late after infarction. Twenty-four patients with MI underwent stress, redistribution, and reinjection thallium SPECT imaging and cine MRI within several days. Seventeen patients underwent imaging late after infarction and 7 underwent imaging early after infarction. Normalized thallium activity was correlated with MRI wall thicknesses at both end-diastole and end-systole for 18 segments for each ventricle. In addition, end-diastolic and end-systolic wall thicknesses were grouped by their corresponding thallium activity levels into percentiles. End-systolic wall thickness correlated significantly with normalized thallium uptake in 14 of 18 segments, end-diastolic wall thickness in only 4 of 18 segments, and wall thickening in only 3 of 18 segments. Mean values for end-diastolic and end-systolic wall thicknesses corresponding to severely reduced (<50%) normalized thallium activity were 9.9 +/- 1.1 and 8.5 +/- 0.6, respectively. Using receiver-operating curve analysis, end-systolic wall performed as a better diagnostic parameter than end-diastolic wall for identifying severely reduced thallium activity levels. For all levels of thallium activity, end-diastolic wall thicknesses were all thinner late versus early after MI, whereas end-systolic wall thickness was thinner only in the segments corresponding to severely reduced thallium activity. Based on these results, end-systolic wall thickness is the best noninvasive anatomic parameter of myocardial scar.

Adult↗
PubMed1997

Ricin-binding proteins along the endocytic pathway: the major endosomal ricin-binding protein is endosome-specific.

Ricin is internalized after binding at the cell surface via lectin activity of the B-chain recognizing terminal galactose residues. Ricin-A chain is then translocated to the cytosol from various endocytic structures. Cell death is the result of catalytic inactivation of protein synthesis. Using (125)I-ricin overlays, we examined the distribution of ricin binding-proteins within highly purified preparations of plasma membrane vesicles, endosomes and lysosomes from lymphocytes. All compartments of the endocytic pathway had distinct profiles; some ricin-binding proteins were present throughout the pathway; others were restricted to the plasma membrane and endosomes. The major endosomal protein recognized by (125)I-ricin, a 166 kDa glycoprotein, was endosome-specific. When endosomal proteins were solubilized before chromatography onto ricin-agarose this protein was also by far the major specifically-bound glycoprotein. This 166 kDa glycoprotein might be involved in ricin translocation from this compartment.

Animals↗
PubMed1996

Translocation of full-length Pseudomonas exotoxin from endosomes is driven by ATP hydrolysis but requires prior exposure to acidic pH.

We attached human transferrin to Pseudomonas exotoxin A (PE) to specifically localize this toxin to the endosomal compartment and study its translocation from purified endosomes using a cell-free assay. Transferrin was linked to PE via a disulfide bond. Chemical derivatization inactivated the PE cell-binding domain, and transferrin-PE was found to be endocytosed via the transferrin receptor only. Transferrin was also conjugated to a truncated PE with no receptor-binding domain (PE46). After labeling mouse lymphocytes with radiolabeled transferrin-PE or transferrin-PE46 and endosome isolation, selective translocation of the full-sized toxin portion of the conjugate was observed in a cell-free system. This translocation was strictly dependent upon ATP hydrolysis and was not affected when the acidity of the endosome lumen was neutralized using weak bases, protonophores, or bafilomycin A1. Nevertheless, when present during cell labeling, inhibitors of endosome acidification prevented PE from acquiring translocation competence. Similar inhibition was observed when endocytosis was performed in the presence of brefeldin A, a drug known to interfere with the delivery of endocytic tracers to acidic endosomes. Our data indicate that full-length PE can be transferred to the cytosol directly from endosomes during intoxication by PE conjugates and that, although exposure to acidic pH is a prerequisite for translocation, ATP hydrolysis directly provides the energy required for PE translocation.

ADP Ribose Transferases↗
PubMed1995

[Association of coronary-pulmonary fistula and intercoronary fistula. Apropos of a case].

The authors present the case of a 30-year-old woman admitted to hospital for investigation of a systolodiastolic murmur. Assessment revealed a fistula between the trunk of the left coronary artery and the pulmonary artery, with an aneurysm on the left anterior descending artery (LAD), associated with an intercoronary anastomosis between the left conus artery and the LAD. Thallium myocardial scintigraphy demonstrated reversible decreased uptake in the anterolateroapical region. Simple coronaro-pulmonary fistulas are a rare disease. The positive diagnosis is suggested by echocardiography and confirmed by coronary angiography. The clinical course is generally favourable, except in the presence of complications such as aneurysm, heart failure or coronary insufficiency. This case raises the difficult problem of the operative indication in these young, usually asymptomatic patients.

Adult↗
PubMed1995

[Mitral valve prolapse and myocardial ischemia. Apropos of 2 cases].

The authors report two cases of severe myocardial ischaemia with healthy coronary arteries associated with mitral valvular prolapse (MVP). The first case was a 43-year-old woman treated with beta-blockers following the discovery of MVP. This patient was admitted to hospital six months later with persistent chest pain in a context of cardiogenic shock. The response to treatment was rapid and spectacular. The second case was a 44-year-old hypertensive smoker man in whom assessment of chest pain revealed several signs of myocardial infarction as well as MVP. This rare combination of MVP and myocardial ischaemia raises pathophysiological as well as therapeutic problems.

Adrenergic beta-Antagonists↗
PubMed1994

Cameroon: an African model for final stages of guinea worm eradication.

The Cameroon Guinea worm eradication program initiated case containment activities in 1991 in the Mayo-Sava Division, the only endemic region in the country. These activities differed from the Pakistan program, the only other operational model for dracunculiasis case containment, in two important ways. In Cameroon, next-level supervisors received reports of new cases from village health workers during routine weekly visits to endemic villages. The Pakistan program established a faster case reporting scheme that allowed higher level personnel (sector supervisors and regional managers) to confirm cases within one week of worm emergence. Second, in Cameroon case containment activities were extended only to villages reporting five or more cases the previous transmission season and villages with recent confirmed cases. In Pakistan, all villages reporting cases during the previous year were included in the program. A village-by-village case search one year after initiation of case containment in the Mayo-Sava indicated decreases of 60% in the number of cases and 51% in the number of villages reporting cases. Based on the apparent success of the efforts in Cameroon, we propose a two-stage scheme for implementation of case containment. Both stages are based on rapid detection and containment of cases, within 24 hr of worm emergence, by village-based health workers. In stage 1, cases are reported and confirmed during routine weekly visits to the endemic villages by next-level supervisors. Weekly reporting should be extended to all villages with recent confirmed cases and to as many villages reporting cases during the previous transmission season as logistically possible.(ABSTRACT TRUNCATED AT 250 WORDS)

Cameroon↗
PubMed1993

ATP-dependent translocation of ricin across the membrane of purified endosomes.

Ricin translocation was demonstrated (using both fluorescence- and radiolabel-based assays) across the membrane of endosomes purified from mouse lymphocytes. Selectivity of the process was shown by the absence of translocation activity of transferrin and horseradish peroxidase used as membrane-bound and fluid-phase endosome labels, respectively. Endocytosed 125I-ricin translocation was found to be strictly ATP- (Km approximately 4 mM) and temperature-dependent, with up to 30% endosomal 125I-ricin appearing in the external medium after 2 h at 37 degrees C. No treatments neutralizing the acidic endosome pH (ammonium chloride, nigericin, chloroquine) significantly impaired ricin translocation, and the pH gradient across the endosome membrane is not required for this process. Chase experiments showed that the ability of 125I-ricin to translocate increases with its depth in the endocytic system (i.e. plasma membrane << early endosomes < late endosomes). Both A and B ricin chains displayed translocation ability as demonstrated by the results of our assay on ricin, ricin B, transferrin-ricin A, and transferrin-ricin B conjugates. Biological activity of both ricin chains is preserved after translocation as shown by the inhibitory effect of the A chain on cell-free protein synthesis and the binding of the B chain to lactose-agarose.

Animals↗