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Biomedical subjects

M Wassef

Publications and source records attributed to M Wassef.

At least 163 records · Page 9Linked to original sources
PubMed1981

The effect of bleeding patterns on the response of haemophilic haemarthroses to different doses of factor VIII.

Three hundred and thirty-nine consecutive bleeds into the knees, elbows and ankles of severe haemophiliacs were graded I if more than 50% of normal movement was present, and graded 2 if less than 50% of normal movement was present. Nursing staff then administered randomly allocated doses of 7,14 or 28 units of factor VIII per kg. Medical staff unaware of initial doses assessed progress thereafter at 12-hourly intervals. Grade I bleeds into "normal" joints showed no difference in response to the three dosage regimes, but grade 2 bleeds did worse on low doses. There was no significant difference in the response to each dose of bleeds into restricted and into target joints. However, when a restricted joint became a target joint as well, both grade I and grade 2 bleeds did badly on low doses. The target joint as well, both grade I and grade 2 bleeds did badly on low doses. The percentage of patients with bleeds into these joints whose range of movement had not returned to baseline 48 h after receiving a low dose of factor VIII was significantly higher than those who had received the higher doses.

Ankle Joint↗
PubMed1981

[Undifferentiated clear cell thyroid carcinoma. Diagnostic interest of ultrastructural study (author's transl)].

Optical and electron microscopy features of an undifferentiated clear cell carcinoma of the thyroid are presented. Tumor cells have irregular, often multiple nuclei, showing numerous mitosis. Diastase-digested P.A.S. positive material is demonstrated in their cytoplasm. Numerous lymphocytes and plasma cells are present in the stroma. Electron microscopy showed large cytoplasmic areas of monoparticular free glycogen, few lipid droplets, numerous desmosomes and some intercellular microvilli. Most cells contained varying amounts of tonofilament bundles suggesting a partial epidermoid differentiation. This atypical appearance has not been described in metastases from clear cel carcinoma of kidney and may assist the primary nature of undifferentiated clear cell thyroid carcinoma.

Adenocarcinoma↗
PubMedDate not supplied

Cardiac functional improvement by a human Bcl-2 transgene in a mouse model of ischemia/reperfusion injury.

BACKGROUND: Apoptosis has been shown to contribute to myocardial reperfusion injury. It has been suggested that, in reducing the apoptotic component within the ischemic area at risk, Bcl-2 overexpression could lead to a ventricular function improvement. METHODS: Transgenic mice overexpressing the anti-apoptotic human Bcl-2 cDNA in heart were subjected to a 1-h left coronary artery occlusion followed by a 24-h reperfusion. At the end of the experiment, left ventricular function was assessed by two-dimensional echocardiography. After sacrifice, the area at risk (AR) and the infarct area (IA) were determined by Evans blue and triphenyltetrazolium chloride staining, respectively. The extent of apoptosis was assessed by the TUNEL method. Non-transgenic littermates served as controls. RESULTS: Baseline AR was not different between Bcl-2 transgenic mice and their wild-type littermates. In contrast, left ventricular ejection fraction was significantly improved in the transgenic mice line (61.25 +/- 4.0%) compared to non-transgenic littermates (43.2 +/- 5.0%, p < 0.01). This functional amelioration was correlated with a significant reduction of infarct size in transgenic animals (IA/AR 18.51 +/- 3.4% vs 50.83 +/- 8.4% in non-transgenic littermates). Finally, apoptotic nuclei were less numerous in transgenic mice than in controls as quantified by TUNEL analysis (8.1 +/- 2.2% vs 20.6 +/- 4.4%). CONCLUSIONS: Bcl-2 overexpression is effective in reducing myocardial reperfusion injury and improving heart function. This benefit correlates with a reduction of cardiomyocyte apoptosis. The apoptotic component of ischemia/reperfusion injury could therefore constitute a new therapeutic target in the acute phase of myocardial infarction.

Animals↗
PubMedDate not supplied

MR-Guided PTA in experimental bilateral rabbit renal artery stenosis and MR angiography follow-up versus histomorphometry.

PURPOSE: To assess in vivo 1) MR-guided percutaneous transluminal renal angioplasty (PTRA) in experimental bilateral rabbit renal artery stenosis (RAS); 2) postprocedural follow-up by gadolinium-enhanced MR angiography versus histomorphometry. METHODS: Fifteen male NZW rabbits of mean weight 4.0 kg (range 3.5-4.2 kg) underwent bilateral RAS induction by combined overdilation-deendothelialization with a gadolinium-filled balloon, passively MR-guided by the artifact of a 0.014-inch guidewire. After 4 weeks the rabbits were randomized into two groups: group A (n = 8) underwent right-sided PTRA for treatment of RAS, group B (n = 7) underwent left-sided PTRA. After another 4 weeks the rabbits were killed to assess by histomorphometry recurrent stenosis and contralateral induction injury stenosis lesions. Each step was preceded by gadolinium-enhanced three-dimensional MR angiography, and the cortex-to-aorta (C/A) signal intensity ratio was calculated. RESULTS: RAS induction was successful in all cases. Fourteen arteries developed restenosis and 13 only initial stenosis. MR-guided PTRAs were feasible in 22 arteries (73%). For a successful catheterization of the ostium (20 arteries, 66% success rate), 10-25 steps were required. Five to eight steps were required for balloon localization and inflation for each PTRA. The restenosis effect was reflected by a 16% (12%-27%) decrease in C/A values on MR angiograms (p < 0.05). CONCLUSION: MR guidance and MR angiography represent a feasible, less invasive alternative for performing and assessing experimental PTRA in RAS.

Angioplasty, Balloon↗
PubMedDate not supplied

Phenotypic and functional characteristics of porcine peritoneal mesothelial cells.

The objective of this study was to establish a technique to isolate porcine mesothelial cells (PMCs) from omental tissue and to compare them to human mesothelial cells (HMCs). The PMCs were dispersed by collagenase digestion and isolated on a Ficoll layer. Their morphologic and ultrastructural features were assessed at confluence by light and electronic microscopy, and they were characterized by immunohistochemistry using specific HMC markers. PMC proliferation was studied in the presence of growth factors platelet-derived growth factor (PDGF), epidermal growth factor (EGF) or transforming growth factors beta1, beta2, or beta3 (TGF). Fibrinolytic PMC activity was detected by zymography for tissue plasminogen activator (tPA) and by reverse zymography for plasminogen activator inhibitor-1 (PAI-1). The recalcification time of cell lysates was used to define PMC procoagulant activity, and gelatinase zymography was used to detect metalloproteinase production. At confluence, PMCs formed typical cobblestone monolayers and exhibited structural features characteristic of HMCs. Weibel Palade bodies were never seen. Specific HMC markers (HBME1, ME1, WT1) cross-reacted with PMCs. As HMCs and PMCs coexpressed cytokeratin and vimentin, and also expressed vinculin and alpha-actin. Addition of PDGF or EGF to the culture medium stimulated PMC proliferation. PMCs constitutively expressed fibrinolytic and procoagulant activity and secreted MMP9 and MMP2. The technique described in this study allows isolation of mesothelial cells from porcine omental tissue. These porcine cells exhibit a mesothelial phenotype and functional properties similar to those of HMCs. Our data warrant an evaluation of mesothelial cells as targets in several therapeutic strategies with porcine models.

Animals↗
PubMedDate not supplied

Direct intratumoral embolization of juvenile angiofibroma.

INTRODUCTION: Embolization is a well-established technique that facilitates the subsequent surgical removal of vascularized tumors such as juvenile angiofibroma. However, there is risk of a neurological accident during angiography and tumor embolization from the internal carotid artery. Direct intratumoral embolization may help prevent these potential side effects. METHOD: A group of 7 patients with juvenile angiofibroma vascularized through the branches of the internal carotid artery underwent direct tumoral embolization under general anesthesia. An injection made slowly with an intranasal or lateral percutaneous route with either a mixture of cyanoacrylate, lipiodal, and tungsten powder. Continuous radiographic control was used. RESULTS: This technique induced a marked devascularization and necrosis of the tumor. The technique provided useful perioperative visualization of the tumor. No neurologic sequelae were encountered. CONCLUSION: Direct intratumoral embolization deserves further consideration. This might be especially important in tumors with extracranial extension, cavernous sinus involvement, or those with small or multiple recurrences.

Adolescent↗
PubMedDate not supplied

Cardiac papillary fibroelastoma: aA rare cause of ischemic stroke in the young.

Among etiologies of stroke in young adults, primary cardiac tumors are very rare. We report the case of a 37-year-old woman who was admitted for an ischemic stroke in the right middle cerebral artery region. Etiologic investigations revealed, after transthoracic and transesophageal echocardiography, an aortic valve tumor. Treatment was first medical with anticoagulation, then surgical. Histological examination showed a papillary fibroelastoma. After a review of the literature, the possible mechanisms of the ischemic event are discussed and lead to the conclusion that this tumor must be surgically excised, even if asymptomatic, because of recurrent ischemic complications responsible for myocardial infarction, stroke and sudden death.

Adult↗
PubMedDate not supplied

A delayed teflonoma of the neck simulating a thyroid neoplasm.

Pseudotumoral granulomatous foreign body reaction to Teflon particles is a rare complication of intracordal Teflon paste injection for unilateral vocal cord paralysis. We report a case of pseudotumor of the thyroid area, which appeared 3 years after intracordal Teflon paste injection and presented as a cold thyroid nodule. At frozen section examination the presence of a giant-cell foreign body granuloma containing numerous refringent particles suggested a 'teflonoma'. The diagnosis was confirmed on permanent sections, after comparison of the intratissular particles with fresh Teflon paste, under conventional and polarized light. The histological and ultrastructural features of the lesion are presented and attention is drawn to the long delay between initial Teflon injection and the clinical manifestation of the lesion.

Aged↗