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Biomedical subjects

A Rizk

Publications and source records attributed to A Rizk.

12 recordsLinked to original sources
PubMed2005

Sex-differences in age-related cognitive decline in C57BL/6J mice associated with increased brain microtubule-associated protein 2 and synaptophysin immunoreactivity.

Understanding cognitive aging is becoming more important as the elderly population grows. Here, the effects of age and sex on learning and memory performance were compared in female and male young (3-4 months old) middle-aged (10-12 months old) and old (18-20 months old) wild-type C57BL/6J mice. Old males and females performed worse than young or middle-aged mice in novel location, but not novel object recognition tasks. Old mice, of both sexes, also showed impaired spatial water maze performance during training compared with young or middle-aged mice, however only old females failed to show robust spatial bias during probe trials. While there was no age-difference in passive avoidance performance for males, females showed an age-related decline. There was no difference in cognitive performance between young and middle-age mice of either sex on any task. Cognitive performance was associated with alterations in immunoreactivity of microtubule-associated protein 2-positive dendrites and synaptophysin-positive pre-synaptic terminals in hippocampal CA1, CA3, and dentate, entorhinal cortex, and central nucleus of amygdala. Overall, microtubule-associated protein 2 immunoreactivity was increased in old females compared with both young and middle-age females with no significant difference in males. In contrast, synaptophysin immunoreactivity increased from young to middle-age in females, and from middle-age to old in males; females had higher levels of synaptophysin immunoreactivity than males in middle-age only. Elevated levels of microtubule-associated protein 2 and synaptophysin may constitute a compensatory response to age-related functional decline in mice.

Adaptation, Physiological↗
PubMed2001

Transfusion-related acute lung injury after the infusion of IVIG.

BACKGROUND: Transfusion-related acute lung injury (TRALI) is a well-characterized, serious complication of blood component therapy in hospitalized patients. The signs and symptoms are often attributed to other clinical aspects of a patient's condition, and therefore TRALI may go unrecognized. IVIG is a pooled plasma derivative commonly used in the outpatient setting. Respiratory complications of IVIG infusion have typically been attributed to volume overload or allergic and vasomotor reactions. TRALI has never been documented to occur after IVIG infusion. CASE REPORT: A 23-year-old man with multifocal motor neuropathy developed noncardiogenic pulmonary edema 6 hours after receiving 90 g of IVIG by a rapid-infusion protocol. He fully recovered in 5 days with nasal oxygen and bed rest. Granulocyte-associated IgG was detected in his blood 14 and 27 weeks after the event. The lots of IVIG that he received were found to contain a low-titer, panreactive, granulocyte antibody, mostly IgG. CONCLUSION: This is the first documented case of TRALI after IVIG infusion. An autoimmune syndrome, including autoantibody-coated granulocytes, may have been a priming stimulus for granulocyte interaction with pulmonary capillary endothelium. Rapid infusion of a large quantity of granulocyte antibody may have precipitated TRALI. A pooled plasma product or derivative may result in TRALI.

Adult↗
PubMed2000

Plasma carnitine levels as a marker of impaired left ventricular functions.

L-Carnitine plays a role in the utilization of fatty acids and glucose in the myocardium. Previous studies have indicated carnitine deficiency in patients with congestive heart failure. However, the extent of altered carnitine metabolism and left ventricular function is not fully determined. This study is designed to determine if plasma L-carnitine levels can serve as a marker for impaired left ventricular function in patients with congestive heart failure. To test this hypothesis, plasma and urinary levels of L-carnitine were measured in 30 patients with congestive heart failure (CHF) and in 10 control subjects. CHF was due to dilated cardiomyopathy (DCM) and rheumatic heart disease (RHD). Cardiac functions such as percentage of fractional shortening (%FS), ejection fraction (EF), left ventricular mass index (LVMI), were determined by echocardiography. All patients and control subjects had normal renal functions. Plasma carnitine was significantly higher in patients with DCM (37.05+/-7.62, p < 0.0001) and with RHD (47.2+/-8.04, p < 0.0001) vs. the control subjects (14.4+/-5.30 mg/L). Urinary carnitine was significantly higher in DCM (49.13+/-14.11, p < 0.0001) and in RHD 43.53+/-15.5, p < 0.0001), than the control (25.1+/-5.78 mg/L). Plasma carnitine level correlated significantly with impaired left ventricular systolic functions in these patients: % FS < 25 % (r = -0.38 and p = 0.038), EF < 0.55 (r = -0.502 and p = 0.005) and LMVI > 124 gm/m2 (r = 0.436, and p = 0.016). These data suggest that elevated plasma and urinary carnitine levels in patients with CHF could serve as a marker for myocardial damage and impaired left ventricular functions.

Adult↗
PubMed1996

[Oncocytoma of the caruncle. Anatomo-clinical study apropos of a case].

A clinico-pathologic case of an oncocytoma of the caruncle is reported in a 60-year old male patient. Clinically a granular reddish painless tumor was observed in the caruncle. A total surgical excision was performed. The histopathological study established the diagnosis of oncocytoma of the caruncle. Although rare, this tumor should be recognized by ophthalmologists, specially in elderly, because of exceptional adenocarcinoma. The oncocytoma is cured by surgical excision.

Adenoma, Oxyphilic↗
PubMed1988

Postmenopausal endometrial patterns and serum estradiol concentrations.

Eighty postmenopausal women were subjected to endometrial biopsy. Inadequate biopsy was recorded in 30 cases. In the remaining cases (n = 50) the correlation between endometrial patterns and serum estradiol (E2) was performed. These cases were presenting with uterine bleeding (n = 38) or minor gynecological symptoms (n = 12). Proliferative endometrium was the predominant endometrial pattern whereas endometrial malignancy was only present in 15.8% of the bleeding cases. Serum E2 was significantly elevated in cases having malignant endometrium or adenomatous hyperplasia compared to cases having other endometrial patterns. Serum E2 measurement is recommended as a simple screening test for the detection of postmenopausal endometrial hyperplasia and/or malignancy.

Biopsy↗
PubMed1988

Plasminogen interactions with platelets in plasma.

In this report we used a fluorescent flow cytometry-based assay to examine plasminogen binding to platelets in plasma. Our data indicate that platelets activated in platelet-rich plasma (PRP) by adenosine-5'-diphosphate (ADP) or thrombin bind plasminogen to their surface. Fab fragments of the monoclonal antibody LJ-CP8 that are directed against the fibrinogen binding site on the glycoprotein (GP) IIb-IIIa complex inhibit both plasminogen and fibrinogen binding to ADP-stimulated platelets as does 5 mmol/L EDTA. Platelet aggregation and plasminogen and fibrinogen binding are also concurrently inhibited by the Gly-Arg-Asp (RGD) analogue Gly-Arg-Gly-Asp-Ser (GRGDS) when it is added to PRP before ADP stimulation. The scrambled peptide analogue SDGRG has no effect. The monoclonal antibody 6D1, directed against the von Willebrand factor binding site on GPIb, has no effect on plasminogen-platelet binding, nor does antithrombospondin antibody. epsilon-Aminocaproic acid (EACA), however, inhibits plasminogen binding to ADP-activated platelets. These data indicate that plasminogen binds to platelets activated in plasma, that binding occurs on platelet GPIIb/IIIa, and that binding may be mediated via plasminogen association with fibrinogen via lysine binding domains. Finally, we found both plasminogen and fibrinogen on resting platelets in PRP and demonstrated that they are equally displaced by EDTA, LJ-CP8, and 10E5 (an additional anti-GPIIb/IIIa monoclonal antibody). Plasminogen is also equally displaced by EACA. These data suggest that plasminogen is also bound to GPIIb/IIIa on resting platelets, possibly also via interaction with fibrinogen.

Adenosine Diphosphate↗
PubMed1985

[Familial paroxysmal polyserositis. Previously unpublished peritoneal complications. A case].

A young unmarried Lebanese woman presenting with periodic disease (familial paroxysmal polyserositis) since she was 3 months old developed recurrent abundant ascites at the age of 21 years. Several hundred millilitres of strongly eosinophilic fluid were evacuated. Exploratory laparotomy unexpectedly disclosed an encapsulating peritonitis with adhesions involving the small bowel and the ascending colon; there were masses of lipid-laden cells, clusters of cholesterol/crystals and marked mesoepithelial reaction. In view of the patient's dramatic response to colchicine 2 mg/day, these findings were regarded as being related to the periodic disease.

Ascites↗
PubMed1978

Electrophysiological demonstration of an excitatory subthalamonigral pathway in the rat.

The subthalamonigral projection was studied with extracellular techniques in the rat. Orthodromic and antidromic stimulations of this pathway were performed in different sets of experiments in order to exclude the possible activation of passing fibers. A majority of the recorded cells in the subthalamic nucleus (STN) were antidromically activated by nigral stimulation. It was furthermore shown that the subthalamofugal fibers are excitatory to cells located in the pars compacta as well as in the pars reticulata of the substantia nigra. The possible existence of another descending STN pathway is also discussed.

Animals↗
PubMedDate not supplied

Bilateral posterior fixation sutures on the medial rectus muscles for correction of nonaccommodative esotropia with infantile onset criteria.

BACKGROUND: Bilateral posterior fixation sutures on the medial rectus muscles can be used in the management of nonaccommodative esotropia with criteria indicative of infantile onset. The postoperative results of posterior scleral fixation of bilateral medial rectus muscles on ocular motility and the angle of esotropia in different directions of gaze, as well as on the near point of convergence, have been studied. METHODS: Twenty-six patients suffering nonaccommodative esotropia of the infantile onset type, showing variable angles, adduction overshooting, and esodeviation, which had started within the first year of life, were examined. The angle of esotropia was measured at near, distance, and in the different directions of gaze. All patients underwent post-equatorial scleral fixation of both medial rectus muscles at 12 mm to 14 mm from the insertion, depending on the preoperative angle of esotropia. RESULTS: With the alternate prism cover test, 20 patients (76.9%) showed an angle <10 prism diopters (delta) in the primary position, as well as in the different directions of gaze. Fifteen of the 20 patients (57.7%) even showed simultaneous perception at near and at distance with Bagolini's striated glasses. Six patients were under-corrected. CONCLUSIONS: Bilateral posterior fixation of the medial rectus muscles is a good procedure to correct the angle of esotropia in patients who meet the following criteria: essential infantile esotropia, showing overacting medial rectus muscles, variable angles, and nonaccommodative convergence excess.

Accommodation, Ocular↗