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Biomedical subjects

S Mohamed

Publications and source records attributed to S Mohamed.

At least 19 recordsLinked to original sources
PubMed2006

Detection of low-frequency lambda-doublet transitions of the free 12CH and 13CH radicals.

By Fourier transform microwave spectroscopy, lambda-doubling transitions of (12)CH and (13)CH in the lowest rotational levels of the X(2) product operator(1/2) ground state have been directly detected, which has not been done previously. For both radicals, hyperfine-split lines have been measured to an accuracy of better than 1 ppm between 3 and 15 GHz, an improvement of at least 2 orders of magnitude over previous laboratory data. The measured frequencies have been combined with all previous data for CH and (13)CH in the v = 0 level of the X(2) product operator electronic state to determine improved hyperfine parameters. The production of CH from various gases also has been studied and, with methanol, the yield of CH relative to OH. Astronomical studies of CH in higher rotational levels and (13)CH can now be undertaken on the basis of the present work.

Astronomical Phenomena↗
PubMed2006

Fluorescence X-ray absorption spectroscopy using a Ge pixel array detector: application to high-temperature superconducting thin-film single crystals.

A Ge pixel array detector with 100 segments was applied to fluorescence X-ray absorption spectroscopy, probing the local structure of high-temperature superconducting thin-film single crystals (100 nm in thickness). Independent monitoring of pixel signals allows real-time inspection of artifacts owing to substrate diffractions. By optimizing the grazing-incidence angle theta and adjusting the azimuthal angle phi, smooth extended X-ray absorption fine structure (EXAFS) oscillations were obtained for strained (La,Sr)2CuO4 thin-film single crystals grown by molecular beam epitaxy. The results of EXAFS data analysis show that the local structure (CuO6 octahedron) in (La,Sr)2CuO4 thin films grown on LaSrAlO4 and SrTiO3 substrates is uniaxially distorted changing the tetragonality by approximately 5 x 10(-3) in accordance with the crystallographic lattice mismatch. It is demonstrated that the local structure of thin-film single crystals can be probed with high accuracy at low temperature without interference from substrates.

Algorithms↗
PubMed2006

Decreasing efficacy of repeated intravitreal triamcinolone injections in diabetic macular oedema.

BACKGROUND/AIM: Intravitreal triamcinolone (IVTA) results in transient improvements in diabetic macular oedema (DMO), necessitating repeated injections. The authors report a case series of 10 eyes of 10 patients with DMO, who received a repeat injection of 4 mg IVTA, at least 26 weeks after the first injection of the same dose. METHOD: Pre-injection and at 2, 4, 9, and 17 weeks post-injection, best corrected visual acuity (BCVA) and central foveal thickness (CFT) on optical coherence tomography, after the first and repeat injections, were compared using paired t test. Side effects were monitored. RESULTS: BCVA, CFT, intraocular pressure (IOP), and cataract scores were not significantly different before initial and repeat injections (given at 32.5 (SD 3.5) weeks after the first injection). Transient improvements of BCVA and CFT were achieved after both injections. However, after the repeat injection, the BCVA was significantly worse at all time points (p<0.05) and so were the best achieved CFT and the CFT at 4 weeks post-injection (p = 0.034 and 0.011 respectively), compared with the initial injection. Post-injection maximum IOPs and increase in cataract scores were not significantly different between the two injections. CONCLUSION: A repeat injection of 4 mg of IVTA may not be as effective as an initial injection for the treatment of DMO.

Aged↗
PubMed2006

Neurocognitive functioning in dually diagnosed middle aged and elderly patients with alcoholism and schizophrenia.

BACKGROUND: Alcohol abuse and dependence have important clinical implications for managing patients with schizophrenia. Alcoholism in schizophrenia patients can interfere with the course and prognosis of the schizophrenic illness. OBJECTIVE: The purpose of the present study was to compare the cognitive status, symptom profile and quality of life of middle aged and older patients (>44 years old) with schizophrenia and alcohol abuse/dependence vs those without alcohol abuse/dependence. We initially hypothesized that more males in this age group with schizophrenia would exhibit alcoholism. We also examined the characteristics of the 45-54 year age group with those of the > or = 55 year old group and hypothesized that comorbidity with alcohol would be associated with worse cognition and quality of life in later life. METHODS: Data were obtained from a database from the Center for Services and Interventions research at the University of California, San Diego. Patients had diagnoses of schizophrenia or schizoaffective disorder. Data collected included demographic characteristics, cognitive status (tested with the Mattis Dementia Rating Scale learning, the Figural and Story Memory Test of the Wechsler Memory Scale-Revised and the California Verbal Learning Test [CVLT]). In addition, patients had undergone psychopathologic assessment and were screened for quality of life using the Quality of Well Being scale. RESULTS: We demonstrated that the older aged patients with alcoholism had worse scores assessing cognition relative to the same aged group without alcoholism. In addition, they had worse cognitive scores relative to the younger group (45-54 year old) with alcoholism. There was no significant difference with regards to quality of life. In addition, more males than females exhibited alcoholism. CONCLUSION: The results are consistent with the premise that the higher cognitive function in the younger schizophrenia patients with alcoholism appear to mask the effects of alcohol use on cognition at that age. However, for the older group of schizophrenia patients, the effects of alcohol use on neuropsychological functioning appear to be deleterious.

Alcoholism↗
PubMed2006

Pro-angiogenesis action of thyroid hormone and analogs in a three-dimensional in vitro microvascular endothelial sprouting model.

AIM: Our laboratory has recently demonstrated the pro-angiogenesis effects of thyroid hormone in the chick chorioallantoic membrane model. METHODS: Generation of new blood vessels from existing vessels was promoted two- to three-fold by either L-thyroxine (T4) or 3,5,3'-triiodo-L-thyronine (T3) at total hormone concentrations of T7-T9 M. RESULTS: T4-agarose, a formulation of thyroid hormone that does not cross the cell membrane, produced a potent pro-angiogenesis effect comparable to that obtained with T3 or T4. In the present investigation, T3, T4, T4-agarose, and basic fibroblast growth factor, each added to vascular endothelial growth factor, produced comparable pro-angiogenesis effects in the in vitro three-dimensional human microvascular endothelial sprouting model. The pro-angiogenesis effect of the thyroid hormone analogs was blocked by PD 98059, an inhibitor of the mitogen-activated protein kinase (MAPK; ERK1/2) signal transduction cascade. A specific avb3 integrin antagonist (XT199) also inhibited the pro-angiogenesis effect of either thyroid hormone analogs or T4-agarose. Tetrac, a thyroid hormone analog that blocks cell surface-initiated actions of T4 and T3, inhibited the pro-angiogenesis response of thyroid hormone. CONCLUSIONS: T4, T3, and T4-agarose are pro-angiogenic in the three-dimensional human microvascular endothelial sprouting model, an action that is initiated at the plasma membrane, involves avb3 integrin receptors, and is MAPK-dependent.

Cells, Cultured↗
PubMed2005

Rotational spectra of the carbon-chain radicals HC5O, HC6O, and HC7O.

Three new free carbon-chain radicals, HC5O, HC6O, and HC7O, and their deuterated isotopic species have been observed by Fourier transform microwave spectroscopy of a supersonic molecular beam. In contrast to the shorter HCnO radicals, these all have linear heavy-atom backbones and 2Pi electronic ground states. Like the isovalent HCnS radicals, the ground states of the HCnO radicals alternate with odd and even numbers of carbon atoms: those of HC5O and HC7O are 2Pi1/2 and that of HC6O is 2Pi3/2. From frequency measurements between 6 and 26 GHz, the rotational constant B, the centrifugal distortion constant D, and the lambda-type doubling and magnetic hyperfine constants have been determined to high precision for each chain. Predicted properties from coupled-cluster calculations are also reported for chains up to HC9O. The production of HCnO radicals for n even was highly favored when O2 was used as the source of oxygen, but those with n odd were best produced with CO.

Journal Article↗
PubMed2005

Phacoemulsification with intravitreal triamcinolone in patients with cataract and coexisting diabetic macular oedema: a 6-month prospective pilot study.

AIMS: To assess the safety and efficacy of phacoemulsification with intravitreal triamcinolone (ivTA) injection in diabetics with cataract and clinically significant macular oedema (CSMO). METHODS: A total of 19 eyes of 15 consecutive diabetic patients with cataract and CSMO were prospectively recruited. Patients underwent phacoemulsification and intraocular lens implantation with 4 mg ivTA injection at completion of surgery. Patients were followed up on day 1, then weekly for 1 month, and thereafter monthly until 6 months postoperatively. Best corrected visual acuity (BCVA), central macular thickness (CMT) measured by optical coherence tomography, and adverse events were recorded. RESULTS: In total, 17 eyes completed 6 months of follow-up. In all, 58.8% showed improvement in BCVA of >or=2 lines, with statistically significant improvement in mean Snellen BCVA of 2.4 lines at 6 months. The peak BCVA was achieved at 4 months. The mean CMT decreased from a baseline of 449 microm to a minimum of 321+/-148 microm (28.5% reduction) achieved at 2 months, with statistically significant reduction at all postoperative time intervals until 6 months. Of 17 eyes, 4 (23.5%) developed transiently elevated intraocular pressure that normalised by 6 months in all but one patient. No injection- or surgery-related complications were encountered. CONCLUSIONS: Phacoemulsification with concurrent 4 mg ivTA injection appears to be a safe option for managing diabetics with cataract and CSMO. However, large-scaled randomised controlled trials are necessary for delineating the relative contributions of cataract removal and CMT reduction to visual improvement. Moreover, the transient effect on CMT may warrant further studies to determine optimal timing and dosage of further ivTA injections.

Aged↗
PubMed2004

Vasorelaxation induced by common edible tropical plant extracts in isolated rat aorta and mesenteric vascular bed.

In this study, the vasodilatory actions of nine edible tropical plant extracts were investigated. Ipomoea batatas (sweet potato leaf), Piper betle (betel leaf), Anacardium occidentale (cashew leaf), Gynandropsis gynandra (maman leaf), Carica papaya (papaya leaf), and Mentha arvensis (mint leaf) extracts exhibited more than 50% relaxing effect on aortic ring preparations, while Piper betle and Cymbopogon citratus (lemongrass stalk) showed comparable vasorelaxation on isolated perfused mesenteric artery preparation. The vascular effect on the aortic ring preparations were mainly endothelium-dependent, and mediated by nitric oxide (NO) as supported by the inhibition of action in the presence of N(omega)-nitro-L-arginine (NOLA), an nitric oxide synthase (NOS) inhibitor, or by the removal of endothelium. In contrast, vasodilatory actions in resistance vessels (perfused mesenteric vascular beds) appear to involve several biochemical mediators, including NO, prostanoids, and endothelium-dependent hyperpolarizing factors (EDHFs). Total phenolic contents and antioxidant capacities varied among different extracts and found to be independent of vascular relaxation effects. This study demonstrates that many edible plants common in Asian diets to possess potential health benefits, affording protection at the vascular endothelium level.

Animals↗
PubMed2004

Brown deposits in the optic of foldable intraocular lenses in patients with uveitis.

PURPOSE: To report a new finding of brown deposits scattered in the substance of the optic of foldable intraocular lenses (IOL) following phakoemulsification in patients with uveitis. METHODS: Consecutive uveitis patients (54 patients, 71 eyes) who had undergone phakoemulsification with a foldable posterior chamber IOL between March 1996 and November 2000 were studied. A variety of biomaterials from seven different manufacturers had been implanted. One masked observer using slit-lamp biomicroscopy assessed deposits in the substance of the optic of the IOL. RESULTS: Brown deposits were detected in the substance of the optic of 25/71 (35%) IOLs with 18/22 (82%) of AcrySof MA60BM IOLs being affected. Using logistic regression analysis, the AcrySof MA60BM IOL was significantly associated with the presence of deposits (adjusted odds ratio=38.5, 95% CI 6.9-200, P<0.001). Using multiple regression analysis, there was a significant association between the severity of deposits and the use of the AcrySof MA60BM IOL (P=0.005). Compared with other foldable IOLs implanted, the AcrySof MA60BM IOL was 38.5 times more likely to develop intra-IOL deposits. There was no association with those eyes that had undergone increased intraocular manipulations. The deposits did not appear to affect visual acuity. CONCLUSIONS: To our knowledge the finding of brown intra-IOL deposits has not previously been described. These deposits are more frequent in the AcrySof MA60BM implant than the other foldable implants studied. They share some similarities with glistenings, but their exact nature remains unknown.

Adult↗
PubMed2004

Inhibition of endothelial cell tube formation by the low molecular weight heparin, tinzaparin, is mediated by tissue factor pathway inhibitor.

Heparin and low molecular weight heparins (LMWHs) have both antithrombotic and anti-angiogenic activities. The anti-angiogenic activity of LMWH may be associated with the release of endothelial tissue factor pathway inhibitor (TFPI), an important endogenous inhibitor of tissue factor/Factor VIIa (TF/fVIIa). To evaluate the effects of LMWH, tinzaparin, and TFPI in a model of angiogenesis-mediated processes, we compared the effects of tinzaparin, and recombinant TFPI in inhibiting either basic fibroblast growth factor-2 (FGF2)- or TF/fVIIa-induced endothelial cell tube formation in human umbilical vein endothelial cells (HUVEC). Our results show that tinzaparin and recombinant TFPI both blocked endothelial tube formation induced by either FGF2 or TF/fVIIa, in a concentration-dependent manner. Endothelial tube formation was only marginally inhibited by a potent and specific anti-Factor Xa, recombinant tick anticoagulant protein (rTAP). A monoclonal anti-TFPI anti-body reversed the inhibitory effects of either tinzaparin or recombinant-TFPI on HUVEC tube formation. Tinzaparin fractions in the range of 8,000 to 12,600 Da were most effective in stimulating the release of TFPI from HUVEC. These results suggest that the inhibitory effect of the LMWH tinzaparin on endothelial tube formation is associated with stimulation of the release of TFPI, but not to anti-Factor Xa activity.

Cells, Cultured↗
PubMed2004

Evaluation of antifungal efficacy in an optimized animal model of Trichophyton mentagrophytes-dermatophytosis.

Dermatophytoses are known to cause considerable discomfort, cosmetic problems and financial loss that have been recognized as a significant health concern worldwide. Since currently available antifungal agents have limitations in their efficacy, new agents are being developed. This study was undertaken to optimize an in vivo model of experimental dermatophytosis for evaluation of the efficacy of antifungal compounds. Guinea pigs were infected with different inocula of T. mentagrophytes to establish dermatophytosis. The optimal conditions for dermatophytosis in guinea pigs were found to be an inoculum size of 1 x 10(7) fungal cells applied on abraded skin. After optimization, animals were treated with oral or topical formulations of terbinafine. The optimized guinea pig model was found to be highly reproducible, and useful in the primary screening and evaluation of the anti-dermatophytic efficacy of topical and oral formulations of antifungal agents.

Administration, Cutaneous↗
PubMed2001

Citalopram augmentation of antipsychotic treatment in older schizophrenia patients.

BACKGROUND: Depressive symptoms are common in older patients with schizophrenia; yet, few studies have examined the usefulness of antidepressants in this population. OBJECTIVE: We conducted a 10-week single-blind trial of citalopram (20-40 mg/day) vs no citalopram augmentation in 19 middle-aged and elderly patients with schizophrenia hospitalized for more than six of the last 12 months. At study-entry, the patients had been on stable doses of antipsychotics for at least two weeks, and had a 17-item Hamilton Depression Rating (HAM-D) scale score of 12 or greater. Nine patients were randomly assigned to citalopram augmentation, and 10 to no augmentation of antipsychotics. RESULTS: Patients in both groups improved on positive and negative symptoms, but the citalopram group had significantly greater improvement in HAM-D and Clinical Global Impression Scale scores than the control group. There were no major side effects. CONCLUSION: Larger double-blind studies are needed to follow up on these preliminary findings.

Aged↗
PubMed2001

Alpha-tocopherol content in 62 edible tropical plants.

Vitamin E was determined by the high-performance liquid chromatography (HPLC) method. All the plants tested showed differences in their alpha-tocopherol content and the differences were significant (p < 0.05). The highest alpha-tocopherol content was in Sauropus androgynus leaves (426.8 mg/kg edible portion), followed by Citrus hystrix leaves (398.3 mg/kg), Calamus scipronum (193.8 mg/kg), starfruit leaves Averrhoa belimbi (168.3 mg/kg), red pepper Capsicum annum (155.4 mg/kg), local celery Apium graveolens (136.4 mg/kg), sweet potato shoots Ipomoea batatas (130.1 mg/kg), Pandanus odorus (131.5 mg/kg), Oenanthe javanica (146.8 mg/kg), black tea Camelia chinensis (183.3 mg/kg),papaya Carica papaya shoots (111.3 mg/kg), wolfberry leaves Lycium chinense (94.4 mg/kg), bird chili Capsicum frutescens leaves (95.4 mg/kg), drumstick Moringa oleifera leaves (90.0 mg/kg), green chili Capsicum annum (87 mg/kg), Allium fistulosum leaves (74.6 mg/kg), and bell pepper Capsicum annum (71.0 mg/kg). alpha-Tocopherol was not detected in Brassica oleracea, Phaeomeria speciosa, Pachyrrhizus speciosa, Pleurotus sajor-caju, and Solanum melongena.

Chromatography, High Pressure Liquid↗
PubMed2001

Flavonoid (myricetin, quercetin, kaempferol, luteolin, and apigenin) content of edible tropical plants.

Studies were conducted on the flavonoids (myricetin, quercetin, kaempferol, luteolin, and apigenin) contents of 62 edible tropical plants. The highest total flavonoids content was in onion leaves (1497.5 mg/kg quercetin, 391.0 mg/kg luteolin, and 832.0 mg/kg kaempferol), followed by Semambu leaves (2041.0 mg/kg), bird chili (1663.0 mg/kg), black tea (1491.0 mg/kg), papaya shoots (1264.0 mg/kg), and guava (1128.5 mg/kg). The major flavonoid in these plant extracts is quercetin, followed by myricetin and kaempferol. Luteolin could be detected only in broccoli (74.5 mg/kg dry weight), green chili (33.0 mg/kg), bird chili (1035.0 mg/kg), onion leaves (391.0 mg/kg), belimbi fruit (202.0 mg/kg), belimbi leaves (464.5 mg/kg), French bean (11.0 mg/kg), carrot (37.5 mg/kg), white radish (9.0 mg/kg), local celery (80.5 mg/kg), limau purut leaves (30.5 mg/kg), and dried asam gelugur (107.5 mg/kg). Apigenin was found only in Chinese cabbage (187.0 mg/kg), bell pepper (272.0 mg/kg), garlic (217.0 mg/kg), belimbi fruit (458.0 mg/kg), French peas (176.0 mg/kg), snake gourd (42.4 mg/kg), guava (579.0 mg/kg), wolfberry leaves (547.0 mg/kg), local celery (338.5 mg/kg), daun turi (39.5 mg/kg), and kadok (34.5 mg/kg). In vegetables, quercetin glycosides predominate, but glycosides of kaempferol, luteolin, and apigenin are also present. Fruits contain almost exclusively quercetin glycosides, whereas kaempferol and myricetin glycosides are found only in trace quantities.

Chromatography, High Pressure Liquid↗
PubMed2001

High levels of oestrogen receptor-alpha in tumorigenesis: inhibition of cell growth and angiogenic factors.

We previously found that the stable overexpression of oestrogen receptor-alpha in the human endothelial cell line ECV304* inhibits its growth in vitro, and that this inhibition is possibly mediated through a down-regulation of the vasoactive agents endothelin-1 and vascular endothelial growth factor. Here we show an in vivo growth-inhibitory effect of oestrogen receptor-alpha overexpression in tumours initiated in nude mice from the same clone of ECV304. In addition, we show that this growth inhibition is accompanied by an alphavbeta3-mediated inhibition of cell migration in vitro, and a down-regulation of the integrin alphavbeta3, vascular endothelial growth factor and vascularization in vivo. The levels of vascular endothelial growth factor and integrin alphavbeta3, through their effect on cell growth and migration, contribute to the process of angiogenesis and to the pathogenesis of atherosclerosis and cancer. The results shown here demonstrate that a higher level of oestrogen receptor-alpha in the cell, through its effect on certain angiogenic factors, may play a role in the control of angiogenesis.

Animals↗
PubMed2001

Tegumental alterations in Schistosoma mansoni worms induced by treatment of infected mice with naproxen pre- and/or post-infection.

Schistosoma mansoni infected mice were treated with naproxen (CAS 22204-53-1) in a dose of 3-4 mg/kg body weight. Treatment was conducted for 7 days before and/or 28 days post infection. Adult worms, developed 7 weeks post infection, were studied by electron microscopy. In both groups, the dorsal surface of the male worms was much more affected by the drug than that of female ones. The most significant morphological degeneration was the change in the aspect and the form of tubercles. Moreover, shrinkage and loss of spines from the ventral surface were also observed. A small portion of the posterior end of female worms showed loss of spines. However, in the first group given naproxen 7 days before infection, the level and extent of changes increased particularly in male worms. There was pronounced oedema, swelling, wrinkling with constriction and collapse of sensory bulbs.

Animals↗
PubMed2001

Hemophilic arthropathy: considerations in management.

The authors evaluate nonsurgical and surgical approaches to treating patients with hemophilic arthropathy and review the functional and economic limitations imposed on treating these patients. Indications for surgery are discussed and a case study that incorporates both conservative and surgical management options is presented. While the advent of factor replacement therapy has dramatically changed the course of treatment and prognosis for patients with hemophilia, the authors argue that the economic burden of treating these patients is still very high. The authors recommend that proper conservative and surgical management options for patients with hemophilia should be based upon a thorough understanding of the disease process.

Adult↗