PubMed Health⌕ Search

Biomedical subjects

M Saad

Publications and source records attributed to M Saad.

32 records · Page 2Linked to original sources
PubMed1994

Causes and consequences of esterase 6 enzyme activity variation in pre-adult Drosophila melanogaster.

We report heritable threefold differences in both larval and pupal esterase 6 activity among 17 isoallelic lines of D. melanogaster extracted from a natural population. The activity differences in the two stages are only weakly correlated with each other or with previously determined values for esterase 6 activity in adults of these lines. The pre-adult activity variation is also unrelated to polymorphisms among the lines for six esterase 6 allozymes and six restriction sites in a region encompassing the esterase 6 coding DNA and the first kbp of 5' flanking DNA. However, two insertions, of 8.0 and 6.8 kbp, located about 1.4 kbp 5' of the esterase 6 coding region are associated with low activity in larvae and, to a lesser extent, in pupae, albeit not in adults. Restriction mapping reveals similarity between the 8.0 kbp insert and the 7.4 kbp retrotransposon 17.6. The differences in larval activity among lines are positively correlated with fitness as assessed from assays of pre-adult viability and development time but no significant associations between pupal esterase 6 activity and these measures are detected. Some effects of esterase 6 allozyme differences are also found for viability and development time but these effects could be explained by linkage disequilibrium between the 8.0 kbp insert and the EST6-9 allozyme.

Adaptation, Biological↗
PubMed1992

[Risk of dislocation and cataract formation in 240 IOGEL lenses. 4 years experiences].

Following planned extracapsular cataract extractions we implanted 240 IOGEL lenses into the capsular bag and noticed 5 dislocations into the vitreous cavity, 2 after an Nd-YAG capsulotomy, 4 postoperatively and 1 after surgical repositioning. Postoperatively, one lens was subluxated into the anterior chamber. Thirty-three patients required a 4- to 5-mm Nd-YAG capsulotomy because of a fibrotic or regenerative secondary cataract. Two lenses dislocated 2 and 6 weeks after the YAG capsulotomy into the vitreous cavity; the capsulotomy was performed 5 and 6 months, respectively, after the implantation. In 4 patients the IOGEL lens dislocated 3 times within the first 3 days and once within the first 3 months after implantation. Primary stable placement in the bag could be achieved, however. One patient required repositioning of the lens because of decentration 3 months after implantation. The lens dislocated on the following day. Late dislocation of the flexible and soft IOGEL lens can be due to the fact that the lenses do not adhere to the capsular sheets. Furthermore, postoperative capsular shrinkage enlarging a posterior capsular opening leads to lens dislocation. Eight patients underwent a secondary anterior chamber lens implantation. In three patients the IOGEL lens was explanted, in two of them without and in one of them with serious complications. The other five patients still have their IOGEL lens deep in the vitreous without complications. We suggest that if a YAG capsulotomy is necessary, it should not be performed before the 6th postoperative month. It should also not exceed 4 mm in diameter and no IOGEL lens should be implanted if a capsular rupture occurs intraoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Cataract Extraction↗
PubMed1991

Schistosoma mansoni nephropathy in Syrian golden hamsters: effect of dose and duration of infection.

In this work, 180 golden hamsters were infected with Schistosoma mansoni and 30 hamsters matched for age and sex served as controls. According to the number of injected cercariae, infected hamsters were divided into six main groups (20, 50, 100, 150, 200 and 250 cercariae). Each group was divided into five subgroups, according to the duration of infection after which animals were sacrificed (4, 6, 8, 12 and 24 weeks). Control and infected hamsters were subjected to laboratory evaluations (serum creatinine, blood urea nitrogen, cholesterol, albumin, total protein and urine protein concentration) and histopathologic examinations of kidney and liver tissues. A significant proteinuria, hypoalbuminemia and hypercholesterolemia was observed in schistosome infected (50 cercariae or more) but not in the controls and the group infected with 20 cercariae. There was significant correlation between these changes and duration of infection and the number of adult worm recovered from the mesenteric circulation at the end of the experiments. Histopathologic evaluation showed appearance of the circulating schistosome antigens, circulating anodic antigen (CAA) and circulating cathodic antigen (CCA), and of IgG glomerular deposits by the 6th week following infection; mesangial hypercellularity appeared early after infection (6-8 weeks), renal amyloid deposition appeared later (8-12 weeks). Egg antigens were not detected in the renal glomeruli. There was a significant correlation between the pathologic changes and duration of infection and the number of recovered adult worms from the mesenteric circulation. No histopathologic lesions were detected in controls and the group injected with 20 cercariae. A significant correlation was found between hepatic periportal fibrosis, amyloidosis and immune complex, deposition in the renal glomeruli. Hamsters did not tolerate infection with 150 cercariae or more for more than 12 weeks, and 20 cercariae caused no detectable glomerular disease. From this study, we concluded that S. mansoni infection causes nephropathy in the Syrian golden hamster. The disease became biochemically and histopathologically manifest by the 6th week following infection. Both immune complex deposition and renal amyloidosis stand as major pathogenic mechanisms. CAA and CCA are the major responsible antigens. Hepatic disease has an impact on the kidney lesion. 50 cercariae are the best dose to produce disease without early death of the animal. There is a significant correlation between the kidney disease and the duration and the load of S. mansoni infection.

Animals↗
PubMed1988

Genito-urinary complications of brucellosis.

Twelve cases of genito-urinary complications of brucellosis are presented. Ten patients had epididymo-orchitis, 1 presented with right hydronephrosis and 1 with haematuria and dysuria. The 10 cases of epididymo-orchitis were compared with 15 cases of acute non-specific epididymo-orchitis. The former were of longer duration and were not associated with lower urinary tract symptoms; almost all of these patients had ingested unpasteurised milk. Non-specific epididymo-orchitis had a more acute onset, shorter duration and was associated more frequently with pyuria, lower urinary tract symptoms, higher leucocyte counts and insignificant brucella titres. The distinction between these two types of epididymo-orchitis is essential, since the treatments are entirely different.

Adolescent↗
PubMed1988

The effect of postnatal development on the adherence of nonfimbriated and fimbriated Salmonella typhimurium to isolated small intestinal enterocytes.

The adherence of radiolabeled fimbriated (S 7471 OF) and nonfimbriated (S 7471 N) Salmonella typhimurium to small intestinal rat enterocytes was examined during postnatal development. The fimbriated strain invariably adhered in higher numbers than the nonfimbriated strain during all periods of development. The capability of enterocytes to bind Salmonella increased significantly during postnatal development and reached adult levels at weaning time (21 days of age). Bacterial adherence to enterocytes was similar if the cells were isolated from the proximal or the distal small intestine. Early weaning of pups did not affect the capability of enterocytes to bind Salmonella. Pretreatment of isolated enterocytes from adult animals with rat's milk before exposure to Salmonella had no effect on the level of bacteria that adhered per enterocyte. Conversely, pretreatment of Salmonella with rats' milk before binding to enterocytes from adult animals also did not alter the level of bacteria adhered per enterocyte. These results suggest an age-dependent, postnatal development of available receptors for S. typhimurium on rat enterocytes. The acquisition of these receptors is not affected by mother's milk and is unaltered by early weaning.

Aging↗
PubMed1987

Specific binding of leukotriene B4 to guinea pig lung membranes.

We have demonstrated binding sites for LTB4 in guinea pig lung membranes. Binding of [3H]-LTB4 was of high affinity (Kd = 0.76 nM), saturable and linear with protein concentration (0.2-1.2 mg/ml). Scatchard and Hill's plot analysis indicated a single class of binding site with a Hill's coefficient of 0.99 +/- 0.08 (n = 4). [3H]-LTB4 was unmetabolized during incubation with membrane preparations, as indicated by high performance liquid chromatography. Divalent cations such as Mg2+ and Ca2+ enhanced binding capacity without changing the Kd. Na+ ions decreased binding in a concentration-dependent manner. Guanine nucleotides, GTP, GTP gamma S and Gpp(NH)p also decreased the number of binding sites. Finally, competition experiments demonstrated the following order of potency for displacement of [3H]-LTB4 from its receptor site: LTB4 greater than 20-OH-LTB4 much greater than 20-COOH-LTB4 = 6-trans-12-epi-LTB4 greater than LTC4 = LTD4 = 5-HETE. These data indicate that a specific LTB4 receptor, in addition to the previously documented LTC4 and LTD4 receptors, exists in guinea pig lung.

Animals↗
PubMed1987

Dual regulation of neutrophil adenylate cyclase by fluoride and its relationship to cellular activation.

1 Fluoride stimulated (1-10 mM) and inhibited (10-100 mM) adenylate cyclase of neutrophil membranes in a GTP-independent manner. The latter fluoride concentration range corresponded to that shown previously to induce cellular responses. 2 Dual regulation of cyclase activity was also exhibited by a nonhydrolysable GTP analogue, guanosine 5'[gamma-thio]triphosphate (GTP gamma S). Inhibition was observed at 0.1-10 nM GTP gamma S while stimulation occurred at greater than 10 nM GTP gamma S. 3 Relatively high levels (greater than microM) of formylmethionyl-leucyl-phenylalanine inhibited adenylate cyclase in the presence of GTP (10 microM). 4 Pertussis toxin pretreatment abolished adenylate cyclase inhibition mediated by GTP gamma S and formylmethionyl-leucyl-phenylalanine but did not influence fluoride-induced inhibition.

Adenylate Cyclase Toxin↗
PubMed1986

In vivo platelet activity and lipoprotein patterns in coronary artery disease.

In order to determine the effect of hyperlipoproteinemia on the in vivo formation of circulating platelet aggregates (CPA) in patients with coronary artery disease, CPA ratios, lipoprotein pattern, serum cholesterol and triglycerides were determinated in 80 male patients with stable coronary artery disease and hyperlipoproteinemia. Similar studies were performed in 30 male age-matched patients with stable coronary artery disease without hyperlipoproteinemia and 60 male age-matched healthy volunteers; the latter group served as controls. CPA ratios were significantly lowered; i.e. an increase was observed in circulating platelet aggregates in 24 patients without hyperlipoproteinemia as compared with the values in the control group. All the cardiac patients with hyperlipoproteinemia had a significantly lower CPA ratio than the patients without hyperlipoproteinemia. Moreover, the lowering in CPA ratio was more marked among patients with type II a hyperlipoproteinemia than in those with type IV. We think that this in vivo test for platelet function may throw more light on the effect of hyperlipoproteinemia on the in vivo aggregation of circulating platelets in patients with coronary artery disease.

Cholesterol↗
PubMedDate not supplied

Acute variceal hemorrhage: the persistent bleeder. A plea for management.

A group of 1910 patients with acutely bleeding esophagogastric varices were managed in the Kasr El Aini sclerotherapy project; 458 of the patients (24%) were lost to follow-up. The remaining patients were studied in five groups: group I (294/401 patients), rigid versus flexible sclerotherapy; group II (254/336 patients), intravariceal versus paravariceal sclerotherapy; group III (174/227 patients), timing of initial sclerotherapy and the optimum frequency of sclerotherapy sessions; group IV (80/99 patients), splenectomy devascularization operation alone versus combined surgery with sclerotherapy; group V (650/847 patients), management of failures of and recurrences after sclerotherapy. The mean period of follow-up was 72 months. Rigid sclerotherapy was significantly superior to flexible sclerotherapy for emergency control of acute bleeding but was associated with significantly more morbidity. Paravariceal injection achieved insignificantly better initial control of bleeding and had more morbidity than intravariceal injection, which obliterated the varices in a significantly larger proportion of patients. Emergency injection of the acute bleeder should be carried out soon after admission, with sclerotherapy sessions repeated every 2 weeks. Combined sclerotherapy with splenectomy and devascularization was significantly more effective for controlling bleeding than surgery alone. Surgery should be done without delay for continued bleeding after the second attempt of sclerotherapy and in patients who rebleed after their third sclerotherapy session. Survival, however, was not significantly improved by the different modalities of sclerotherapy.

Arteries↗