Biomedical subjects

I Ali

Publications and source records attributed to I Ali.

At least 19 recordsLinked to original sources

PubMed2003

Equilibrium uptake and sorption dynamics for the removal of a basic dye (basic red) using low-cost adsorbents.

Waste carbon slurries (generated in fertilizer plants) and blast furnace slag (generated in steel plants) have been converted into low-cost potential adsorbents. The adsorbents have been characterized and tried for the removal of the dye basic red from wastewater. Studies were performed at different pH to find the pH at which maximum adsorption occurs. Equilibrium isotherms were determined to assess the maximum adsorption capacity of the adsorbents. Adsorption capacities are compared for activated carbon developed from fertilizer waste and activated slag developed from blast furnace waste. The adsorption data are correlated with Freundlich and Langmuir isotherms in each system. The kinetics of adsorption depends on the adsorbate concentration and the physical and chemical characteristics of the adsorbent. Studies were conducted to delineate the effect of pH, temperature, initial absorbate concentration, particle size of the adsorbent, and solid-to-liquid ratio. The adsorption of basic red was found to be endothermic and first-order in nature.

Journal Article↗

PubMed2003

Dependence of radiochromic film optical density post-exposure kinetics on dose and dose fractionation.

Radiochromic film (RCF) has been shown to be a precise and accurate secondary planar dosimeter for acute exposure radiation fields. However, its application to low dose-rate brachytherapy has been questioned because of possible dose-rate effects. To address this concern, we have measured the optical density (OD) of Model 55-2 RCF as a function of time (interval between the completion of irradiation and densitometry using a 633 nm laser scanner) following exposure (from less than 1 hour to 90 days) for single and split doses from 1 Gy to 100 Gy. Our work demonstrates that film darkening as a function of post-irradiation time depends significantly on total dose, with films exposed to lower doses developing faster than films given higher doses. At 1 Gy, the OD 90 days after exposure is 200% larger than that measured 1 h after exposure compared to a 20% increase over 90 days for doses larger than 20 Gy. An empirical model with time-independent, fast and slow growth terms was used to fit single exposure data. The dependence of the resulting best-fit parameters on dose was investigated. Splitting the dose into two fractions (20 Gy followed by doses of 1-80 Gy 24 h later) results in modest post-irradiation time-dependent changes in the total optical density (at most 15% at small doses), which dissipates within 20 hours following the second exposure. This experimental finding is consistent with the predictions of a simple cumulative dose superposition model. Overall, both experimental and empirical modeling suggest that dose-rate effects may be relatively small despite the strong dependence of film darkening kinetics on total dose. However, more experimental evaluation of radiochromic film response dependence on dose rate and dose-time-fractionation patterns is needed.

Brachytherapy↗

PubMed2002

Bupropion (Zyban) toxicity.

Bupropion is a monocyclic antidepressant structurally related to amphetamine. Zyban, a sustained-release formulation of bupropion hydrochloride, was recently released in Ireland, as a smoking cessation aid. In the initial 6 months since it's introduction, 12 overdose cases have been reported to The National Poisons Information Centre. 8 patients developed symptoms of toxicity. Common features included tachycardia, drowsiness, hallucinations and convulsions. Two patients developed severe cardiac arrhythmias, including one patient who was resuscitated following a cardiac arrest. All patients recovered without sequelae. We report a case of a 31 year old female who required admission to the Intensive Care Unit for ventilation and full supportive therapy, following ingestion of 13.5g bupropion. Recurrent seizures were treated with diazepam and broad complex tachycardia was successfully treated with adenosine. Zyban caused significant neurological and cardiovascular toxicity in overdose. The potential toxic effects should be considered when prescribing it as a smoking cessation aid.

Adult↗

PubMed2002

Thermodynamic study of the enantiomeric resolution of flurbiprofen by HPLC using Chiralpak AD-RH column.

The chiral resolution of (+/-)-flurbiprofen was achieved using water-acetonitrile (60:40, v/v) containing 0.1% acetic acid on a Chiralpak AD-RH column at 20 degrees C. The enantio-resolution was studied with different percentages of acetonitrile. Thermodynamic parameters (enthalpy, entropy and free energy) were calculated by carrying out the enantio-resolution experiments at 0 to 60 degrees C. The enantio-resolution was found to be exothermic in nature. Attempts have been made to explain the mechanism of chiral resolution of flurbiprofen on the Chiralpak AD-RH column.

Chromatography, High Pressure Liquid↗

PubMed2001

Photoelectron diffraction mapping: molecules illuminated from within.

We demonstrate the use of a multiparticle coincidence technique to image the diffraction of an electron wave whose source is placed at a specific site in a free molecule. Core-level photoelectrons are used to illuminate the molecule from within. By measuring the vector momenta of two molecular fragments and the photoelectron, a richly structured electron diffraction pattern is obtained in a body-fixed frame of the randomly oriented molecule in the gas phase. We illustrate this technique for CO, creating a photoelectron from the C(1s) shell and scanning its energy from zero to 30 eV.

Journal Article↗

PubMed2001

Environmental exposure of the pediatric age groups in Cairo City and its suburbs to cadmium pollution.

In a trial to assess the exposure of subjects in the pediatric age group to cadmium (Cd) pollution, serum Cd was estimated by atomic absorption spectrometry in 405 subjects, birth-18 years old, from Cairo City and its suburbs. Serum Cd mean concentrations were: 0.92 microg/l in 32 neonates (birth-4 weeks); 1.33 microg/l in 70 infants (4 weeks-2 years); 1.11 microg/l in 100 children in the preschool period (2-6 years); 1.34 microg/l in 103 primary school children (6-12 years); and 1.24 microg/l in 100 adolescents (12-18 years). In neonates, serum Cd was higher in babies with weights and heights that remained below the 5th percentile for age. Breast-fed infants had a serum Cd geometric mean level (1.25 microg/l) that was not in accordance to that of their mothers' milk (0.52 microg/l, P < 0.001), suggesting alternative routes of exposure. Environmental tobacco-smoke exposure was the most important determinant of Cd status in the school-aged children, the geometric mean being 1.42 microg/l in passive smokers vs. 1.2 microg/l in non-exposed children (P < 0.05). Moreover, adolescents who were active smokers had a significantly higher serum Cd level (1.7 microg/l) as compared to non-smokers (1.2 microg/l). Gender did influence the Cd status in adolescents, being higher among males, probably related to smoking, or to the difference in lifestyle of adolescents according to gender in the community. Alpha-1-microglobulinuria was accompanied by a higher serum Cd concentration in the group of adolescents only, suggesting a subclinical renal effect after several years of cumulative exposure. The residential classification, whether urban or suburban, did not influence the serum Cd status; neither did the present or past history of bronchial asthma. These findings certainly justify further evaluation of the problem of Cd pollution among Cairene individuals, knowing the long-term consequences of exposure to it. Systematic efforts for the proper disposal of Cd wastes and prevention of smoking in public places are recommended.

Adolescent↗

PubMed2001

Studies on the effect of alcohols on the chiral discrimination mechanisms of amylose stationary phase on the enantioseparation of nebivolol by HPLC.

The chiral recognition mechanism of amylose CSPs has been described by achieving the enantiomeric resolution of (+/-)-nebivolol on Chiralpak AD and Chiralpak AD-RH columns with methanol, ethanol, 1-propanol, 2-propanol, 1-butanol as mobile phases at different flow rates. The energies of interactions of methanol, ethanol, 1-propanol, 2-propanol and 1-butanol with both phases were calculated. The (+)-RRRS enantiomer eluted first when using methanol, ethanol and 1-propanol, while the elution order was reversed when using 2-propanol and 1-butanol as the mobile phases. It has been concluded that the reversal elution order observed was due in part to the chiral cavities on the amylose CSP which were responsible for the bondings of different magnitude between chiral stationary phase and enantiomers, which are influenced with the type of alcohol used as mobile phase on the conformation of the 3,5-dimethyl phenyl carbamate moiety on the pyranose ring system of the amylose.

2-Propanol↗

PubMed2001

Chrysotile asbestos fibers detected in the newborn pups following gavage feeding of pregnant mice.

Female pregnant mice were fed chrysotile asbestos suspension by gavage to determine whether there is transfer of fibers to the fetuses. Groups of mice were given 2 doses of either 50 microg chrysotile suspension in 0.2 ml sterile normal saline (treated), or 0.2 ml saline (control), and were allowed to mate 2 d later. After pregnancy was confirmed, the treated and control groups received 2 additional doses of chrysotile asbestos or saline on gestational d 7 and 12. Both groups were allowed to deliver naturally, and the pups were sacrificed at 8, 1, 19, or 20 d after birth. The lungs and liver of two pups from each mother were processed for fiber counts using electron microscopy and energy-dispersive x-ray analysis (EDXA). All pups of the treated group had chrysotile fibers, while none were present in pups from controls. The mean fiber count of the lungs of treated group of pups was 780 fibers/g, and the mean fiber count of the liver was 214 fibers/g. Mean length of the fibers in the lung and liver was 18.48 microm and 18.30 microm, respectively. The fibers were thin, measuring 0.42 microm and 0.33 microm in the lung and liver, respectively. There was no significant difference in the weight gain between the treated and control group of pups. The postnatal fetal mortality of the 2 groups, 8.2% for the treated and 4.5% for the control group, were not statistically significant. To our knowledge, this is the first animal study to demonstrate that oral ingestion of chrysotile asbestos during pregnancy results in transfer of asbestos fibers to the fetuses.

Administration, Oral↗

PubMed2001

A comparative study of the enantiomeric resolution of several tetralone derivatives on macrocyclic antibiotic chiral stationary phases using HPLC under normal phase mode.

The enantiomeric resolution of five substituted 2-(4-pyridylalkyl)-1-tetralone derivatives has been achieved on three macrocyclic glycopeptide antibiotic chiral stationary phases namely, Chirobiotic R, T, and V columns. The mobile phase used was hexane-ethanol-triethylamine (12:8:0.01, v/v/v). The flow rates were 1 mL/min for Chirobiotic T and 2 mL/min for Chirobiotic R and V respectively. The UV detection was carried out at 254 nm. The values of alpha of the resolved enantiomers of the reported tetralone derivatives were in the range of 1.32 to 2.51 on Chirobiotic R, 2.02 to 2.88 on Chirobiotic T and 1.55 to 2.54 on Chirobiotic V respectively while the values of Rs were in the range of 1.00 to 2.50 on Chirobiotic R, 1.00 to 1.95 on Chirobiotic T and 1.00 to 1.60 on Chirobiotic V respectively. The best resolution was achieved on Chirobiotic R column.

Anti-Bacterial Agents↗

PubMed2001

Comparison of the chiral resolution of econazole, miconazole, and sulconazole by HPLC using normal-phase amylose CSPs.

Resolution of the enantiomers of (+/-)-econazole, (+/-)-miconazole, and (+/-)-sulconazole has been achieved on different normal-phase chiral amylose columns, Chi-ralpak AD, AS, and AR. The mobile phase used was hexane-2-propanol-diethylamine, 400:99:1 (v/v). The flow rates of the mobile phase used were 0.50 and 1.00 mL min(-1). The alpha values for the resolved enantiomers of econazole, miconazole, and sulconazole on the chiral phases were in the range 1.63 to 1.04; the Rs values varied from 5.68 to 0.32.

Amylose↗

PubMed2001

Pharmacological comparison of human homomeric 5-HT3A receptors versus heteromeric 5-HT3A/3B receptors.

The present study determined the detailed pharmacological profile of heterologously expressed human (h) homomeric 5-HT3A receptors in direct comparison to heteromeric h5-HT3A/3B receptors. The very minor differences in their respective pharmacological profiles indicates that the 5-HT3B receptor subunit alters, predominantly, the biophysical rather than the pharmacological properties of the 5-HT3 receptor.

Free Radical Scavengers↗

PubMed2001

Removal of DDD and DDE from wastewater using bagasse fly ash, a sugar industry waste.

Bagasse fly ash, a waste from the sugar industry, was converted into an effective adsorbent and was used for the removal of DDD [2,2-Bis(4-chlorophenyl)-1,1-dichloroethane] and DDE [2,2-Bis(4-chlorophenyl)-1,1-dichloroethene] pesticides from wastewater. The DDD and DDE are removed by the developed adsorbent up to 93% at pH 7.0, with the adsorbent dose of 5 g/l of particle size 200-250 microns at 30 degrees C. The removal of these two pesticides was achieved up to 97-98% in column experiments at a flow rate of 0.5 ml/min. The adsorption was found to be exothermic in nature. The bagasse fly ash system has been used for the removal of DDD and DDE from the wastewater. The developed system is very useful, economic, and reproducible.

Carbon↗

PubMed2001

Nodal vessels disease as a risk factor for atrial fibrillation after coronary artery bypass graft surgery.

OBJECTIVE: Atrial fibrillation (AF) is common after coronary artery bypass graft (CABG) surgery. Atrial ischaemia due to diseased atrioventricular (AV) and sinoatrial (SA) arteries has been proposed as a cause of AF post-CABG. We examined if the presence of diseased nodal arteries was a significant predictor of the development of AF post-CABG. METHODS: 100 consecutive cases (AF post-CABG) were compared to 100 consecutive controls (No AF post-CABG) with respect to pre-operative angiographic evidence of diseased nodal arteries. Cases and controls identified from the Society of Thoracic Surgeons database underwent detailed chart reviews to obtain data on potential risk factors. Patients were excluded if they were undergoing anything but a routine CABG procedure, were older than 65 years, or had previous AF. All angiograms were reviewed by a single radiologist blinded to outcome. The effect of grafting diseased nodal arteries on the development of AF post-CABG was also measured. A multiple logistic regression model was utilized to measure the effect of disease in each artery on the development of AF post-CABG. RESULTS: Cases and controls were comparable regarding potential risk factors, with the exception that the AF group was older than the non-AF group. Significant AV artery disease was detected in 78 cases compared to 74 controls (adjusted odds ratio (OR) OR=1.04, CI, 0.51-2.12, P=0.82). Significant SA artery disease was detected in 34 cases compared to 21 controls (adjusted OR=2.093, CI: 1.06-4.09, P=0.03). Six of ten patients having revascularization of their SA nodal artery developed AF versus 28 of 45 of those who did not (OR=0.91, CI: 0.18-5.06, P=0.58). Forty-eight of 87 patients having revasacularization of their AV nodal artery developed AF versus 30 of 65 of those who did not (OR=1.44, CI: 0.72-2.88, P=0.27). CONCLUSION: The presence of a diseased SA artery is significantly associated with AF post-CABG. Such association may be used to identify a subset of patients who might be targeted with prophylaxis.

Aged↗

PubMed2001

HPLC enantiomeric resolution of nebivolol on normal and reversed amylose based chiral phases.

Racemic nebivolol, a beta-adrenergic blocker showing very promising beta-adrenergic antagonist properties in comparison to other beta-adrenergic blockers has been resolved by HPLC under normal and reversed phase modes. The columns used were Chiralpak AD and Chiralpak AD-RH containing amylose tris (3,5-dimethyl phenyl carbamate) as the chiral selector. The mobile phases used were pure ethanol and 1-propanol. The flow rates used were 0.5, 1.0 and 1.5 ml/min. The best resolution was achieved at 0.5 ml/min. flow rate with ethanol and 1-propanol on both Chiralpak AD and Chiralpak AD-RH stationary phases. The values of infinity for both alcohols on Chiralpak AD were 1.38 while on Chiralpak AD-RH these values were 1.41 and 1.38 respectively. The values of Rs for ethanol and 1-propanol were 2.63 and 1.71 on Chiralpak AD and 1.73 and 1.76 on Chiralpak AD-RH respectively.

Adrenergic beta-Antagonists↗

PubMed2000

Hemolysis of human red blood cells by riboflavin-Cu(II) system.

The photodynamic action of riboflavin is generally considered to involve the generation of reactive oxygen species, whose production is enhanced when Cu(II) is present in the reaction. In the present study we report that photoactivated riboflavin causes K(+) loss from fresh human red blood cells (RBC) in a time dependent manner. Addition of Cu(II) further enhances the K(+) loss and also leads to significant hemolysis. Riboflavin in a 2:1 stoichiometry with Cu(II) leads to maximum K(+) loss and up to 45% hemolysis. Bathocuproine, a specific Cu(I)-sequestering agent, when present in the reaction, inhibits the hemolysis completely. Free radical scavengers like superoxide dismutase, potassium iodide and mannitol inhibited the hemolysis up to 55% or more. However, thiourea was the most effective scavenger showing 90% inhibition. These results suggest that K(+) leakage and hemolysis of human RBC are basically free radical mediated reactions.

Copper↗

PubMed2000

HPLC enantiomeric resolution of novel aromatase inhibitors on cellulose- and amylose-based chiral stationary phases under reversed phase mode.

The chiral resolution of seven aromatase inhibitors (four triazole derivatives (Ia, Ib, Ic, and Id) and three tetrazole derivatives (IIa, IIb, and IIc)) was achieved on Chiralcel OJ-R [cellulose tris (4-methyl benzoate)], Chiralcel OD-RH [cellulose tris (3,5-dimethylphenyl carbamate)], and Chiralpak AD-RH [amylose tris (3,5-dimethylphenyl carbamate)] chiral stationary phases. The mobile phases used were A: 2-PrOH-MeCN (90:10, v/v); B: 2-PrOH-MeCN (50:50, v/v); C: MeCN-H(2)O (50:50, v/v); D: MeCN-H(2)O (80:20, v/v); and E: MeCN-H(2)O (95:05, v/v). The flow rate was 0.5 mL/min for all the mobile phases. The resolution capability of these chiral stationary phases were in the order Chiralpak AD-RH > Chiralcel OD-RH > Chiralcel OJ-R. The values of alpha and Rs of the resolved enantiomers of the aromatase inhibitors varied from 1.02-5.63 and 1. 12-6.72, respectively.

Amylose↗

PubMed2000

Impaired activation of cytosolic phospolipase A(2) in inflamed canine colonic circular muscle.

BACKGROUND & AIMS: Arachidonic acid (AA) is a critical second messenger in several cell types. We examined whether cholinergic AA acts as a second messenger in contraction of colonic circular muscle cells and if this role is altered by inflammation. METHODS: The experiments were performed on single dispersed cells. AA release was measured by high-performance liquid chromatography. Escherichia coli membranes labeled with (3)H-AA were used as a substrate for determining phospholipase A(2) (PLA(2)) activity, and Western immunoblotting for protein expression. RESULTS: Acetylcholine and the PLA(2) activator melittin induced cell contractions and AA release. Both effects were inhibited by the PLA(2) inhibitor ONO-RS-082. Cytosolic and membrane PLA(2) activities increased in response to acetylcholine. These were blocked by ONO-RS-082 and cytosolic PLA(2) 100-kilodalton antibody, but not by dithiothreitol, a secretory PLA(2) inhibitor. Acetylcholine- and melittin-stimulated release of AA and their contractile response were attenuated in inflamed cells. Immunoblotting indicated that the protein expression of cPLA(2) was suppressed during inflammation. CONCLUSIONS: AA acts as a second messenger in muscarinic receptor-activated contractions of colonic circular muscle cells. cPLA(2) is the primary enzyme that releases AA in these cells; its expression as well as activation are significantly attenuated by inflammation. The attenuated release of AA may partly account for the inhibition of colonic circular muscle tone and phasic contractions observed during inflammation.

Acetylcholine↗

PubMed2000

Progress in cancer chemoprevention: development of diet-derived chemopreventive agents.

Because of their safety and the fact that they are not perceived as "medicine," food-derived products are highly interesting for development as chemopreventive agents that may find widespread, long-term use in populations at normal risk. Numerous diet-derived agents are included among the >40 promising agents and agent combinations that are being evaluated clinically as chemopreventive agents for major cancer targets including breast, prostate, colon and lung. Examples include green and black tea polyphenols, soy isoflavones, Bowman-Birk soy protease inhibitor, curcumin, phenethyl isothiocyanate, sulforaphane, lycopene, indole-3-carbinol, perillyl alcohol, vitamin D, vitamin E, selenium and calcium. Many food-derived agents are extracts, containing multiple compounds or classes of compounds. For developing such agents, the National Cancer Institute (NCI) has advocated codevelopment of a single or a few putative active compounds that are contained in the food-derived agent. The active compounds provide mechanistic and pharmacologic data that may be used to characterize the chemopreventive potential of the extract, and these compounds may find use as chemopreventives in higher risk subjects (patients with precancers or previous cancers). Other critical aspects to developing the food-derived products are careful analysis and definition of the extract to ensure reproducibility (e.g., growth conditions, chromatographic characteristics or composition), and basic science studies to confirm epidemiologic findings associating the food product with cancer prevention.

Biomarkers↗