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Biomedical subjects

S Sabri

Publications and source records attributed to S Sabri.

At least 19 recordsLinked to original sources
PubMed2005

Familial predictors of childhood shyness: a study of the United Arab Emirates population.

OBJECTIVES: Phobic anxiety disorders generally breed true. In this regard, family studies have suggested an association between childhood shyness and maternal social phobia. In this study, the relationship between childhood shyness and maternal social anxiety was examined. SUBJECTS AND METHODS: 203 5-year-old children from an Arabian Gulf community and their mothers were evaluated. The children were assessed in stage 1 using the shyness scale of Stevenson-Hinde and Glover and the Preschool Behavior Checklist (PBCL), while mothers completed the Liebowitz Social Anxiety Scale. In the second stage, blind clinical interviews were carried out to ascertain the diagnosis of psychiatric diagnoses, if any, using DSM-IV criteria. RESULTS: 27% of the children were identified as shy using the shyness scale of Stevenson-Hinde and Glover and 19% scored above the cutoff for behavioral disturbance on the PBCL. Child shyness was associated with female gender and maternal social anxiety as indicated by scores on the Liebowitz Social Anxiety Scale, while an inverse relationship was noted with behavioral disturbance. The odds of the child having a high shyness score was increased if the mother had social anxiety (odds ratio = 2.14) and the child lived in a family that was 'not socially active' (odds ratio = 1.42). CONCLUSION: Our initial findings suggest that there may be a complex interaction between maternal social anxiety and family sociability in childhood shyness. Prospective longitudinal work is indicated.

Adult↗
PubMed2005

Correlation between hypertension and income distribution among United Arab Emirates population.

To determine the correlation between hypertension and income distribution among United Arab Emirates (UAE) population. Case-control study matched for age, sex, nationality and education. The survey included 500 hypertensive adults aged 20-65 years ascertained from Primay Health Care (PHC) Clinics along with a randomly selected sample of 500 control subjects from the community. Face-to-face interviews were done where data were gathered on socio-demographic-economic status (SES) and lifestyle habits. Hypertension was defined according to WHO criteria as having Systolic Blood Pressure (SBP) > or = 140 mm Hg and/or Diastolic Blood Pressure (DBP) > or = 90 mm Hg and/or being on antihypertensive treatment. The survey was carried out in urban and semi-urban PHC Clinics. A total of 818 subjects were included in this study from a sample of 1000; 409 cases and 409 controls. There were 422 males and 396 females in this study, with 255 UAE nationals and 438 expatriates. Hypertension was found to be significantly higher among the low income group (35.2% vs. 24.9% controls, p = 0.002; while mean SBP in the low income group was 130.2 +/- 17.6 vs. 128.0 +/- 17.4 controls, p = 0.022). Among males, smoking and alcohol consumption were higher among the group with low income level but only smoking showed significant difference (p value = 0.016). Activity level was higher among the low income groups. This study supports the importance of socio-economic factors as an income distribution effect on life-style habits and hypertension.

Adult↗
PubMed2004

Zyxin is up-regulated during megakaryocytic differentiation of human UT-7/c-mpl cells.

To characterize genes involved in megakaryocytic commitment, we compared expression profiles of bipotent cells (UT-7/c-mpl) with those of the same cells induced to differentiate towards megakaryopoiesis in the presence of TPO. Using cDNA arrays, we showed that 12 out of 2260 genes changed their expression level after 6h of TPO stimulation. One of these genes encodes for zyxin, a cytoskeleton protein component. Zyxin is up-regulated at the mRNA and protein levels in UT-7/c-mpl cells in response to TPO confirming the reliability of the cDNA array technology. Similarly, when CD34 positive cells were induced to differentiate into megakaryocytes, zyxin mRNA was accumulated. Furthermore, when megakaryocytes were allowed to spread on fibrinogen, formation of stress fibers and lamellipodia was induced and zyxin was localized at the picks of actin stress fibers. These results suggest an important role for zyxin during megakaryocytic differentiation and more precisely in the regulation of the integrin mediated adhesion process in megakaryocytes.

Antigens, CD34↗
PubMed2001

Role of p21(Cip1/Waf1) in cell-cycle exit of endomitotic megakaryocytes.

The cyclin-dependent kinase inhibitor p21(Waf-1/Cip-1) is expressed at high level during megakaryocyte differentiation, but its precise function remains unknown. In this study, it is confirmed that p21 was expressed at a high level in hypoploid (2N and 4N) and polyploid (at least 8N) human megakaryocytes derived from CD34(+) cells. A high expression of p27(Kip1), p16, cyclin E, and cyclin D3 was also found in both populations associated with a hypophosphorylated form of retinoblastoma protein, suggesting that the majority of hypoploid and polyploid megakaryocytes are G(1)-arrested cells. As human megakaryocytes grown in vitro present a defect in their polyploidization, the study switched to the murine model. The modal ploidy of megakaryocytes derived from lineage-negative cells was 32N, and an elevated expression of p21 was found in high-ploidy megakaryocytes. In addition, p21 and p27 were coexpressed in the majority of mature polyploid megakaryocytes. The p21 was detected by immunofluorescence in megakaryocytes derived from p53(-/-) mice, demonstrating a p53-independent regulation during megakaryocyte differentiation. Megakaryocytopoiesis of p21(-/-) mice was subsequently studied. No marked abnormality in the ploidy of primary or cultured megakaryocytes was detected. Overexpression of p21 in p21(-/-) or normal murine megakaryocytes and in human megakaryocytes showed in all these cases a marked inhibition in megakaryocyte polyploidization. In conclusion, while a reciprocal relation is observed between p21 levels in megakaryocytes and the cycling state of the cells, p21 is not essential for the determination of the ploidy profile in normal megakaryocytes in vivo. However, high levels of its expression in cultured megakaryocytes arrest the endomitotic cell cycle.

Animals↗
PubMed2001

Childhood behavioural disturbance in a community sample in Al-Ain, United Arab Emirates.

The prevalence of behavioural and emotional problems was evaluated among 620 United Arab Emirates nationals aged 6-18 years using the Rutter Parent Questionnaire. Of these children, 11.8% scores above the cut-off point indicating behavioural disturbance. The prevalence of conduct problems was greater among boys, while emotional problems were more common among girls. Certain unspecified chronic life difficulties, parental distress in relation to their children, family history of psychiatric illness and alcohol or drug use in a family member were associated with behavioural disturbance, but no significant association was found with gender, socioeconomic status, family size or recent life events. Our findings suggest that behavioural disturbance exists among a substantial number of school-aged children in the community.

Child↗
PubMed2000

Radiation-induced expression of functional Fas ligand in EBV-positive human nasopharyngeal carcinoma cells.

Ionizing radiation remains a major therapeutic tool against human cancers, especially epithelial tumors, which account for the majority of human malignancies. Although Fas and Fas-L are essential determinants of apoptosis, few data support their role in the cytotoxic effect of ionizing radiation. Epstein-Barr-virus (EBV)-positive nasopharyngeal carcinoma (NPC) were chosen to address this question owing to their known sensitivity to ionizing radiation and their constitutive expression of the Fas-receptor. We here report that, in xenografted NPC cells, Fas-L expression, which was very low in basal conditions, was dramatically increased by tumor irradiation. Both the Fas receptor and the Fas ligand were found to be functional in this model, and a high proportion of irradiated NPC cells underwent apoptosis following tumor irradiation. Induction of Fas-L expression and apoptosis were observed for doses as low as 2 Gy. These data show an increase in Fas-L expression upon irradiation exposure, and strongly suggest that, in some epithelial malignancies, Fas-mediated apoptosis can play a major role in the anti-tumor effect of ionizing radiation, in the range of doses used for therapeutic applications.

Animals↗
PubMed2000

Comparative CD43 behavior on monocytes and lymphocytes in kidney transplants.

In human cultured monocytic cells stimulated by cytokines, CD43 was demonstrated to exhibit a modification of sialylated epitopes (dys-sialylation) [Soler et al: Leukoc Biol 1997;61:609-618]. Therefore, we chose to investigate CD43 behavior on patients who present pathological status implicating monocytes after renal graft (KTR). We performed flow cytometry after immune staining using monoclonal antibodies to CD43 sialic acid-dependent (L60) and -independent (L10) epitopes. Compared to normal controls, mean fluorescence intensity was never altered on lymphocytes. Conversely, on monocytes, we found different profiles with L60: 26% of patients having normal CD43 expression, 54% displayed decreased values and 20% had a double population of monocytes, the major one being normal and the minor one with a very low staining. Decreased values were more frequent among KTR during the first 3 months following transplantation. L10 immunostaining was not altered on monocytes in patients with low values of CD43 staining by L60, confirming that the mechanism involved was a CD43 dys-sialylation. We investigated a possible role of cyclosporin (CsA) on human monocytic (THP-1) and lymphoid (Jurkat) cell lines. CsA decreases CD43 expression in monocytic and not in lymphoid cell lines and could be responsible for the specific dys-sialylation of KTR monocytes. Whatever, CD43 dys-sialylation might lead to functional abnormalities of monocytes in KTR, possibly involving the adhesion process.

Adolescent↗
PubMed2000

Glycocalyx modulation is a physiological means of regulating cell adhesion.

Here we present experimental evidence that phagocytic cells use modulation of specific components of their glycocalyx to regulate their binding capacity. Particles coated with antibodies specific for the CD32 medium affinity IgG receptor were driven along human monocytic THP-1 cells (expressing CD32) in a flow chamber operated at low shear rate. Surprisingly, only minimal adhesion was observed. However, when cells were activated by exposure to fibronectin-coated surfaces and/or soluble &ggr; interferon, adhesion efficiency was dramatically increased, whereas the apparent glycocalyx thickness displayed 20% decrease, and the surface density of CD43/leukosialin carbohydrate epitopes displayed 30-40% decrease on activated cells. The existence of a causal link between adhesion increase and glycocalyx alteration was strongly supported by the finding that (i) both phenomena displayed similar kinetics, (ii) an inverse relationship between THP-1 cell binding capacity and glycocalyx density was demonstrated at the individual cell level, and (iii) adhesion enhancement could not be ascribed to an increased binding site density or improved functional capacity of activated cells. Additional experiments revealed that cell-to-particle adhesion resulted in delayed (i.e. more than a few minutes) egress of CD43/leukosialin from contact areas. Since the time scale of particle attachment was less than a second, surface mobility should not affect the potential of CD43 to impair the initial step of adhesion. Finally, studies performed with fluorescent lectins suggested that THP-1 cell activation and increased adhesive potential were related to a decrease of O-glysosylation rather than N-glycosylation of surface glycoproteins.

Cell Adhesion↗
PubMed1997

Interest of image processing in cell biology and immunology.

Microscopy is a basic tool for cell biologists. Recent progress of electronics and computer science made powerful methodologies for digital processing of microscopic images easily available. These methods allowed impressive increase of the power of conventional microscopy. Dramatic image enhancement may be achieved by combination of filtering techniques, computer-based deblurring and contrast enhancement. Quantitative treatment of digitized images allows absolute determination of the density of different components of the observed sample, including antigens, intracellular calcium and pH. Morphometric studies are also greatly facilitated by image processing techniques. The capture of fast phenomena may be performed by transfer of small portion of microscopic images into computer memory as well as particular use of confocal microscopy. Finally, improved display of experimental data through coded colors or other procedures may enhance the amount of information that can be conveyed by visual examination of microscopical images. The purpose of the present review is to describe the basic principles of image processing and exemplify the power of this approach with a variety of illustrated applications to conventional, fluorescence or electron microscopy as well as confocal microscopy.

Image Processing, Computer-Assisted↗
PubMed1995

Chemical constituents of Artemisia arborescens and the effect of the aqueous extract on rat isolated smooth muscle.

Phytochemical analysis of the ground aerial parts of Artemisia arborescens resulted in the isolation from the ethanolic extract of the known compounds: artemitin, arborescin, sesamin, (+)-lirioresinol beta-dimethyl ether, chrysoeriol, apigenin, beta-sitosteryl glucoside, dihydroridentin, and chrysoeriol 4-glucoside. The last six compounds are isolated from this plant for the first time. The same fraction also yielded the new eudesmanolide jordanolide (1). The effect of an aqueous extract of the plant was studied on rat isolated ileum, uterus, and urinary bladder. The aqueous extract (AE) caused a concentration-dependent reduction in the amplitude of the phasic contractions and in the tone of the ileum. On the other hand, AE caused a significant increase in the frequency as well as the amplitude of the phasic contractions and increased the tone of the isolated uterus and the urinary bladder strips. On the uterus, quinacrine, an inhibitor of the release of arachidonic acid and its metabolites, and indomethacin, a cyclooxygenase inhibitor, potentiated rather than inhibited the effects of AE on this tissue. These observations are discussed in relation to the use of the plant extract in folk medicine.

Animals↗
PubMed1993

Effects of oblongine chloride, an alkaloid from Leontice leontopetalum on guinea-pig isolated smooth muscle and heart.

1. The effects of (-)oblongine chloride, a quaternary alkaloid from Leontice leontopetalum, on guinea-pig isolated ileal longitudinal segments, main pulmonary artery rings, spontaneously-beating atrium and isolated perfused heart were studied. 2. Oblongine chloride (3 x 10(-5)-10(-3) M) caused concentration-dependent relaxation of ileum, an effect which was not blocked by propranolol (10(-6) M) alone or in combination with prazosin (3 x 10(-8) M), or by indomethacin (10(-6) M), but was reduced by desensitization of the preparation by prior exposure to 3 x 10(-5) M ATP and, at high concentrations of oblongine, by a combination of propranolol and yohimbine (3 x 10(-6) M). 3. Oblongine chloride (10(-5)-3 x 10(-3) M) caused concentration-dependent relaxation of epinephrine-precontracted pulmonary artery. This effect was not affected by propranolol or by indomethacin but was significantly attenuated by pretreatment with 3 x 10(-5) M ATP and potentiated by pretreatment with quinacrine (10(-5) M). 4. Oblongine chloride (10(-5) M-3 x 10(-3) M) caused concentration-dependent increase in the contractility but did not affect the rate of the atrium. Similar effects were obtained with isolated perfused heart except that large concentrations of oblongine (10(-3), 3 x 10(-3) M) inhibited both contractility and rate of the heart. The inotropic effects of oblongine on the atrium were not blocked by propranolol or indomethacin but were significantly blocked by quinacrine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1993

Isolation and biological effects of 7-O-methyleriodictyol, a flavanone isolated from Artemisia monosperma, on rat isolated smooth muscles.

The isolation for the first time from the genus Artemisia (Compositae) of the known flavanone, 7-O-methyleriodictyol (7-methoxy-5,3',4'-trihydroxy-flavanone), its identification, and its biological effects on rat isolated smooth muscles are described. 7-O-Methyleriodictyol (10(-7) M to 3 x 10(-4) M) caused concentration-dependent inhibition of the amplitude of the phasic contractions and reduced the tone of the ileum, the uterus, and the urinary bladder. It also caused relaxation of the phenylephrine-precontracted pulmonary artery and the acetylcholine-precontracted trachea. The flavanone also shifted to the right the acetylcholine concentration-effect curve on the ileum and the oxytocin concentration-effect curve on the uterus. The maximum contractions induced by acetylcholine or oxytocin were also inhibited by 7-O-methyleriodictyol. These antispasmodic effects are partly consistent with the use of A. monosperma in folk medicine for certain gastrointestinal disorders.

Animals↗
PubMed1989

Preliminary observations on the pharmacology of petaline chloride, a quaternary alkaloid from Leontice leontopetalum.

1. Low concentrations of petaline chloride (1-300 micrograms/ml) caused relaxation of the epinephrine-contracted aorta, contraction of the ileum, and no effect on the trachea. 2. Larger concentrations (up to 3 mg/ml) caused nonsustained large contractions of the aorta and the trachea and increased the amplitude of the phasic contractions of the ileum. 3. The above effects were not inhibited in the presence of atropine. 4. Petaline chloride increased, in a concentration-dependent manner, the contractions of the spontaneously-beating atrium and the isolated perfused heart. 5. The effects of petaline chloride on the atrium and on the perfused heart were not affected by propranolol but were significantly reduced in the presence of quinacrine, suggesting the participation of arachidonic acid metabolism to this effect. 6. In anesthetized rats, petaline chloride (0.3-3 mg/100 g body weight; i.p.) increased both the systolic and diastolic blood pressure and increased the heart rate.

Alkaloids↗
PubMed1989

Effects of 3,3'-di-O-methylquercetin on guinea-pig isolated smooth muscle.

The effects of the flavone 3,3'-di-O-methylquercetin (DOMQ) have been examined and compared with those of quercetin, on guinea-pig isolated ileum, trachea, and main pulmonary artery (MPA). Except for transient contractions induced by low concentrations (10(-8)-3 x 10(-6) M), DOMQ and quercetin (up to 3 x 10(-4) M) caused reduction of the tone and the phasic contractions of the ileum. A23187 reversed the inhibitory effects of quercetin but not those of DOMQ. DOMQ and quercetin caused concentration-dependent relaxation of the trachea and the adrenaline-contracted MPA. DOMQ shifted to the right the concentration-effect curves induced by acetylcholine on the ileum and the trachea, and by adrenaline on MPA and those induced by CaCl2 on ileum, trachea and MPA. DOMQ also inhibited the contractions induced, in Ca2+-free EGTA-containing buffer, by histamine on ileum and by adrenaline on MPA. These observations suggest that DOMQ inhibits Ca2+ influx, Ca2+ release from intracellular stores and, more likely, Ca2+ binding to intracellular receptor proteins.

Acetylcholine↗
PubMed1988

Effects of hispidulin, a flavone isolated from Inula viscosa, on isolated guinea-pig smooth muscle.

1. In small concentrations (10(-7)-3 X 10(-6) M), hispidulin caused concentration-dependent contraction of isolated guinea-pig ileum and only mild relaxation of guinea-pig tracheal rings. 2. Larger concentrations (up to 3 X 10(-4) M) caused concentration-dependent relaxation of the ileum and the trachea. All the effects on the ileum and the trachea are reversible upon removal of the compound. 3. In concentrations from 10(-7) to 3 X 10(-4) M, hispidulin had no effect on the tone of the epinephrine-contracted rings of the guinea-pig main pulmonary artery. 4. Hispidulin caused a shift to the right of the acetylcholine concentration-effect curves on ileum and trachea and significantly inhibited the maximum contractions induced by acetylcholine. 5. In Ca2+-free, depolarizing solution, hispidulin caused both a shift to the right, and an inhibition of the maximum contractions, of the CaCl2 concentration-effect curves on ileum, trachea and pulmonary artery. 6. In Ca2+-free, EGTA-containing solution, hispidulin caused concentration-dependent inhibition of the contractions induced in the pulmonary artery by epinephrine and in the ileum by histamine. 7. These observations suggest that hispidulin may interfere with Ca2+ binding to the Ca2+-receptor protein(s) in the smooth muscle cell and/or with the agonist-induced Ca2+-release from intracellular stores. Less likely, hispidulin may interfere with Ca2+ influx through smooth muscle cell membrane.

Animals↗
PubMed1973

Extended deep femoral angioplasty.

At present reconstructive arterial surgery for atherosclerotic disease below the level of the inguinal ligament is restricted to femoropopliteal bypass grafts. We have found a new operation, which we call extended deep femoral angioplasty, to be effective not only in some cases where bypass is possible but also in many cases where it is impossible because of a poor run-off, lack of a suitable vein, or even when a bypass has failed. In a consecutively treated group of 34 patients operative reconstruction was limited to the deep femoral artery and a success rate of 65% was achieved. Most gratifying was the saving of a leg in eight patients in whom bypass was impossible.

Amputation, Surgical↗