Biomedical subjects

M Rabbani

Publications and source records attributed to M Rabbani.

At least 19 recordsLinked to original sources

PubMed2006

Photocatalytic degradation of C.I. Acid Red 27 by immobilized ZnO on glass plates in continuous-mode.

The photocatalytic degradation of C.I. Acid Red 27 (AR27), an anionic monoazo dye of acid class, in aqueous solutions was investigated with immobilized ZnO catalyst on glass plates in a continuous-mode. In the slurry ZnO system the separation and recycling of the photocatalyst is practically difficult. Thus, ZnO was immobilized on solid supports to solve this problem. The removal percent increases with increasing the photoreactor volume and light intensity but it decreases when the flow rate is increased. With decreasing flow rate from 43 to 15mlmin(-1), the complete decolorization and degradation was obtained at around 748 and 1080cm(3) from photoreactor volume. The increase in the light intensity from 21.4 to 58.5Wm(-2) increases the decolorization from 23 to 57.6% and degradation from 17.5 to 37.8% for 374cm(3) of photoreactor volume. NH(4)(+), NO(3)(-), NO(2)(-) and SO(4)(2-) ions were analyzed as mineralization products of nitrogen and sulfur heteroatoms. Results showed that final concentration of SO(4)(2-) ions and N-containing mineralization products were less than the finally expected stoichiometric values. The positive slope of production of NH(4)(+), NO(3)(-) and NO(2)(-) shows that these compounds are initial products resulting directly from the initial attack on the nitrogen-to-nitrogen double bond (-NN-) of the azo dye.

Amaranth Dye↗

PubMed2006

Protective effects of calcium-magnesium soft gels in morphine tolerant and dependent mice.

The present study was aimed at evaluating the acute effects of Calcium-Magnesium soft gels (CalMag) in morphine tolerant and dependent mice. Mice were rendered tolerant and dependent on morphine by subcutaneous injection of morphine over a fixed time period. Withdrawal signs were precipitated by injecting naloxone 2 h after the final injection of morphine. The tail-pinch assay was used to investigate the effects of various compounds on the development and reversal of morphine tolerance. Acute injection of CalMag (containing 50 mg/kg calcium and 25 mg/kg magnesium) significantly reduced the number of jumps, stands and fast breathing in morphine dependent mice. Co-administration of calcium (50 mg/kg) and magnesium (25 mg/kg) was also effective in preventing the development of morphine tolerance and dependence. Administration of calcium (up to 50 mg/kg) alone did not significantly block the development of tolerance and dependence. The mean latency to pain was significantly increased in animals pretreated with CalMag (containing 50 mg/kg calcium and 25 mg/kg magnesium). The mixture of calcium and magnesium at specific concentrations seem to be critical for preventing the development of morphine tolerance and dependence.

Animals↗

PubMed2005

Anxiolytic effects of Salvia reuterana Boiss. on the elevated plus-maze model of anxiety in mice.

The anxiolytic and sedative effects of hydroalcoholic extract (HE) of Salvia reuterana Boiss. was evaluated in mice. The HE of Salvia reuterana (100 mg/kg), increased the percentage of time-spent and the percentage of arm entries in the open arms of the elevated plus-maze. Spontaneous locomotor activity count measured in 15 min of the test was significantly decreased in animals pretreated with diazepam and 100 mg/kg of Salvia reuterana extract. Results of the present study provide support for the traditional usage of Salvia reuterana as a sedative and anxiolytic medicinal plant.

Animals↗

PubMed2005

Photooxidative degradation of Acid Red 27 in a tubular continuous-flow photoreactor: influence of operational parameters and mineralization products.

The decolorization and mineralization of Acid Red 27 (AR27), an anionic monoazo dye of acid class, was investigated using UV radiation in the presence of H2O2 in a tubular continuous-flow photoreactor as a function of oxidant concentration, reactor length, flow rate and light intensity. The removal efficiency of AR27 depends on the operational parameters and increases as the initial concentration of H2O2 and light intensity are increased but it decreases when the flow rate is increased. The AR27 degradation was followed through HPLC, UV-vis and COD analyses. The results of these analyses showed that the final outlet stream from the photoreactor was completely mineralized. The UV/H2O2 process was also able to mineralize nitrogen and sulfur heteroatoms into NH4+, NO3-, NO2- and SO4(2-) ions, respectively. The nitrogen of azo group was transformed predominantly to NH4+ ions. Decreasing the flow rate results in the reduction of COD and promotion of SO4(2-) at the final outlet stream of the photoreactor.

Amaranth Dye↗

PubMed2005

Hydroalcohol extract and fractions of Stachys lavandulifolia Vahl: effects on spontaneous motor activity and elevated plus-maze behaviour.

The present study aimed to investigate the anxiolytic effects of four fractions of Stachys lavandulifolia Vahl. The aerial parts of the plant were extracted with petroleum ether (PF), ethyl acetate (EF), butanol (BF) and water (AF) and tested for spontaneous motor activity and elevated plus-maze (EPM) behaviour in mice. The hydroalcohol extract (HE) and different fractions of S. lavandulifolia were administered intraperitoneally to male Syrian mice, at various doses, 30 min before the behavioural evaluation. The HE of S. lavandulifolia (at 50 mg/kg) increased the percentage of time spent (39%) and the percentage of arm entries in the open arms (53%). The HE (50 mg/kg), PF (25 and 50 mg/kg), EF (25 and 50 mg/kg) and AF (50 mg/kg) of S. lavandulifolia significantly increased the percentage of time spent and the percentage of arm entries in the open arms. The BF up to a dose of 50 mg/kg had no significant effects on any of the measured parameters in the EPM. The spontaneous locomotor activity was significantly decreased in animals injected with each plant fractions, compared with that of saline. The EF and AF showed the least and the most reduction in the activity, respectively. The anxiolytic effects of EF, PF and AF could be related to their content of flavonoids, phenylpropanoids or terpenoids.

Animals↗

PubMed2004

Critical effect of hydrogen peroxide concentration in photochemical oxidative degradation of C.I. Acid Red 27 (AR27).

The photochemical decolorization of C.I. Acid Red 27 (AR27), an anionic monoazo dye, was studied in the UV/H2O2 process by using a batch reactor with a UV-C lamp emitting at 254 nm (30 W). The decolorization rate follows pseudo-first order kinetic with respect to the AR27 concentration. The results indicate that the apparent reaction rate constant in the UV/H2O2 process is a function of H2O2 concentration. In this work, a mathematical relation between the apparent reaction rate constant of the AR27 removal and used H2O2 was established. The applied amount of H2O2 was performed in two forms: (i) the light fraction absorbed by H2O2 in 254 nm, (ii) the initial concentration ratio of H2O2 to AR27. The results obtained from this mathematical model are in good agreement with experimental results.

Amaranth Dye↗

PubMed2004

Anxiolytic effects of Echium amoenum on the elevated plus-maze model of anxiety in mice.

The ethanolic extract of Echium amoenum flowers at the dose of 50 mg/kg increased the percentage of time-spent and the percentage of arm entries in the open arms of the elevated plus-maze (EPM) and decreased the percentage of time-spent in the closed arms of EPM. Moreover, it prolonged the ketamine-induced latency to sleep but had no significant effects on total sleeping time induced by ketamine. Also, the locomotor activity was affected but not to the same extent as observed for diazepam. These results suggested that the extract of E. amoenum seems to possess anxiolytic effect with lower sedative activity than that of diazepam.

Animals↗

PubMed2003

Anxiolytic effects of Stachys lavandulifolia Vahl on the elevated plus-maze model of anxiety in mice.

Interest in alternative medicine and plant-derived medications that affect the "mind" is growing. The aim of the present study was to investigate the effects of a hydroalcoholic extract and essential oil of Stachys lavanduifolia Vahl on the elevated plus-maze (EPM) model of anxiety. The Stachys lavandulifolia extract or its essential oil was administered intraperitoneally to male TO mice, at various doses, 30 min before the behavioral evaluation. The extract of Stachys lavandulifolia at the dose of 100 mg/kg increased the percentage of time spent and the percentage of arm entries in the open arms of the EPM and decreased the percentage of time spent and the percentage of arm entries in the closed arms of the EPM. The plant extract at doses lower than 100 mg/kg had no significant effects on any of the parameters measured on the EPM. This dose of the plant extract prolonged the ketamine-induced sleeping time, and decreased the locomotor activity in mice. These results suggested that the extract of Stachys lavandulifolia possessed anxiolytic effect with relatively lower sedative activity than diazepam. The essential oil of Stachys lavandulifolia, however, at doses of up to 100 mg/kg did not have any significant effects on the mice behaviour on the EPM.

Animals↗

PubMed2003

Direct labelling of octreotide with 99mTc: effect of different concentration of reducing agents and amount of sodium pertechnetate on radiolabelling efficiency.

Octreotide, a synthetic analog of natural hormone somatostatin, was labelled with 99mTc. Labelling was accomplished by reduction of the cysteine bridge, which provided sulfhydryl groups for chelating with 99mTc. Sodium ascorbate and sodium dithionite in different concentrations were used as reducing agents. Different amounts of sodium pertechnetate were used for labelling of peptide. When the mass ratio of peptide and sodium ascorbate was 1:100 and the final concentration of dithionite in the labelling vial was 0.2-0.4 microg/microl with 0.18-1.48 GBq sodium pertechnetate more than 80% radiolabelling efficiency was confirmed by RP-HPLC, ITLC-SG and C18 Cartridge analysis. The stability of the 99mTc-peptide bond was evaluated by human serum challenge and that showed the stability was 90% after 4h.

Chromatography, High Pressure Liquid↗

PubMed2001

Chronic ethanol treatment reduces adenylyl cyclase activity in human erythroleukemia cells.

Characteristic changes of platelet membrane adenylyl cyclase activity have been described in men with alcoholism. We studied the occurrence of these changes in human erythroleukemia (HEL) cells after chronic ethanol treatment. Chronic treatment of the HEL cell with ethanol (50 or 100 mM) for 48 h resulted in significant reduction of prostaglandin E1-stimulated adenylyl cyclase activity. The acute ethanol (200 mM, 5 min) enhancement of adenylyl cyclase activity was significantly reduced after chronic ethanol treatment. We also observed a reduction in phorbol-12,13-dibutyrate (PDB) enhancement of prostaglandin E1-stimulation after chronic ethanol treatment. Chronic ethanol treatment (50 or 100 mM) reduced the activity of adenylyl cyclase in response to stimulation by acute ethanol to a greater extent than that of after acute PDB. The increase in cAMP formation by ethanol and PDB was only evident when prostaglandin E1 was present and under basal conditions (when no stimulatory agent was present) ethanol up to 200 mM, and PDB up to 1 M, had no significant effect on adenylyl cyclase activity. The reduced capacity of ethanol and/or PDB to stimulate adenylyl cyclase activity after chronic ethanol treatment suggests the involvement of a common denominator in the action of ethanol and PDB.

Adenylyl Cyclases↗

PubMed1999

Increases in neuronal Ca2+ flux after withdrawal from chronic barbiturate treatment.

Chronic barbital treatment significant increased the net K+-stimulated uptake of 45Ca2+ in cerebrocortical synaptosomal preparations, 24 h after withdrawal from chronic barbital administration. Basal uptake was not significantly changed. Hippocampal synaptosomal preparations showed a similar pattern, but the increase was not significant. The synaptosomal Ca2+ uptake was not affected by incubation with the dihydropyridine Ca2+ channel antagonist, nitrendipine, in controls or after chronic barbital treatment. Acute administration of a single dose of barbital did not alter the basal or stimulated uptake of 45Ca2+ in cortical synaptosomes, when this was measured 36 h after the barbital administration. Hippocampal slices prepared 24 h after withdrawal from chronic barbital treatment showed a significant increase in K+-stimulated uptake of 45Ca2+, and the basal uptake was significantly decreased. Both changes were prevented by nitrendipine. An increase in the density of dihydropyridine-sensitive binding sites was found in the cerebral cortex. The results indicate that both dihydropyridine-sensitive and insensitive neuronal Ca2+ channels are altered by chronic barbiturate treatment. These changes may be involved in physical dependence on barbiturates.

Animals↗

PubMed1999

Salmonella Thompson associated with improper handling of roast beef at a restaurant in Sioux Falls, South Dakota.

In October 1996, we investigated an outbreak of Salmonella serotype Thompson infections associated with Restaurant A in Sioux Falls, South Dakota, and conducted two cohort studies among persons who ate at luncheons catered by Restaurant A. Fifty-two Salmonella Thompson infections were identified between 29 September and 14 October 1996. Infections occurred among employees and patrons at Restaurant A and among attendees at three luncheons catered by the restaurant on 7 October. Roast beef cooked at Restaurant A was the only food item significantly associated with illness. Cooking times and storage temperatures for roast beef were inadequate to prevent multiplication of Salmonella, and the chefs were unaware of proper cooking and storage temperatures. We conclude that improper handling of roast beef probably caused this outbreak of Salmonella Thompson infections. Better knowledge of food safety practices by the cooking staff at Restaurant A, through required food safety education, might have prevented the outbreak.

Adolescent↗

PubMed1999

Role of protein kinase C in ethanol-induced activation of adenylyl cyclase.

Ethanol is known to enhance the activity of adenylyl cyclase (AC) in a number of cells and tissues. Recent work has suggested that the various isoforms of AC show differential sensitivity to ethanol, with Type VII AC being most sensitive. However, the mechanism of action of ethanol is unclear. In the present work, we investigated the effect of ethanol on AC activity in the human erythroleukemia (HEL) cell line, platelets, and AC VII-transfected HEK 293 cells. The HEL cells contain abundant amounts of mRNA for Type VII AC. We found that both ethanol and phorbol dibutyrate (PDBu) treatment enhanced agonist (prostaglandin E1; PGE1)-stimulated AC activity in HEL cells, as well as in platelets and HEK 293 cells transfected with AC VII. Inhibitors of protein kinase C (PKC) blocked the stimulatory effects of both ethanol and PDBu. However, the effects of ethanol and PDBu on AC activity were additive, suggesting that the mechanisms of action of ethanol and PDBu were not identical. Furthermore, a 30-min exposure of HEL cells to ethanol attenuated (desensitized) the ability of ethanol, but not PDBu, to enhance agonist-activated AC activity. On the other hand, a 30-min pretreatment with PDBu attenuated the AC response to the phorbol ester, but not to ethanol; but, after a 20 hr preincubation with phorbol ester, the ability of both PDBu and ethanol to enhance prostaglandin E1-stimulated AC activity was completely eliminated. Finally, pretreatment of HEL cells with pertussis toxin blocked the effect of PDBu, but not ethanol, on AC activity. The results support the involvement of phorbol ester-sensitive PKC(s) in ethanol's enhancement of agonist-activated activity of AC in HEL cells, but suggest that the mechanism of ethanol's action is different from that of PDBu. The findings with pertussis toxin suggest that PDBu activation of PKC(s) may affect AC activity through phosphorylation of a G1 protein, whereas ethanol may act by promoting phosphorylation of a different substrate (e.g., AC VII).

Adenylate Cyclase Toxin↗

PubMed1995

Tolerance to competitive NMDA antagonists, but no crosstolerance with barbiturates.

Tolerance occurred to the sedative actions of the competitive NMDA antagonists, CGP39551 and CGP37849, as measured by a decrease in spontaneous locomotor activity after 1 week or 2 weeks of administration, respectively, in studies using the TO strain of mice. Crosstolerance was seen between these compounds. When CGP37849 was given after 2 weeks treatment with CGP39551, an increase in locomotor activity was seen. Chronic barbiturate treatment, producing tolerance to the actions of pentobarbitone, did not affect the sedative properties of CGP39551 or CGP37849. Chronic treatment with CGP39551 did not alter the ataxic actions of pentobarbitone. Seven days of treatment with HA966 caused complete tolerance to its sedative actions, but no crosstolerance was seen to pentobarbitone, CGP39551, or CGP37849. A small but significant decrease was seen in the convulsion thresholds to NMDA after 15 days of treatment with CGP39551, and a small significant increase in ratings of convulsive behavior after 16 days injections of CGP37849. No significant changes were found in either Bmax or Kd for [3H]-MK-801 binding in cerebrocortical tissue 24 h after the last chronic treatment with either of the NMDA antagonists.

2-Amino-5-phosphonovalerate↗

PubMed1994

Dihydropyridine-sensitive calcium channels and barbiturate tolerance and withdrawal.

We have shown previously that the dihydropyridine calcium channel antagonist nitrendipine, given chronically, prevents the development of ethanol tolerance and physical dependence. The present study examines the effects on barbiturate tolerance and physical dependence. Nitrendipine, given acutely during withdrawal, provided little protection against barbiturate withdrawal, as measured by convulsive behaviour on handling. When nitrendipine was given chronically concurrently with the barbiturate, a prolonged protection against the withdrawal syndrome was seen. Acute nitrendipine significantly increased the latency of seizures in response to the partial benzodiazepine inverse agonist FG7142 during barbiturate withdrawal, but there was no effect on the seizure incidence in response to bicuculline. Chronic treatment with nitrendipine did not alter the development of tolerance to the ataxic or general anaesthetic actions of barbiturates, but evidence was found of a possible interaction between nitrendipine and pentobarbitone, which may have been pharmacokinetic. The results suggest that neuronal calcium channels may be involved to some degree in the development of the changes responsible for barbiturate withdrawal, but to a less extent than found previously for ethanol dependence.

Anesthesia, General↗

PubMed1994

Possible involvement of NMDA receptor-mediated transmission in barbiturate physical dependence.

1. The competitive antagonists at the N-methyl-D-aspartate (NMDA) receptor, CGP39551 and CGP37849, protected against the barbiturate withdrawal syndrome in mice, as measured by ratings of convulsive behaviour on handling. 2. The effective doses of these compounds were lower than those required to prevent seizures due to NMDA in naive animals; these were in turn lower than those needed to prevent the convulsive effects of the alpha-aminobutyric acid (GABA) antagonist, bicuculline. 3. The NMDA-receptor antagonists did not alter the increase in the incidence of convulsions due to the GABAA antagonist, bicuculline, that is seen during barbiturate withdrawal, although the latencies to these convulsions during barbital withdrawal were significantly increased after CGP39551. 4. Barbiturate withdrawal did not affect the convulsive actions of NMDA, whether measured by the incidence of convulsions or by intravenous infusion. 5. The Bmax for [3H]-dizocilpine ([3H]-MK801) binding was significantly increased by chronic barbital treatment in cerebrocortical but not in hippocampal tissues, while the Kd remained unaltered in either case. 6. At 1 h and 24 h after administration of a single dose of barbitone, the Bmax for [3H]-dizocilpine binding was unaltered in cerebrocortical tissue. Acute addition of barbitone in vitro did not alter [3H]-dizocilpine binding or the displacement of binding of thienylcyclohexylpyridine.

2-Amino-5-phosphonovalerate↗

PubMed1991

Image compression techniques for medical diagnostic imaging systems.

As a result of recent technological advances, a significant (and increasing) number of the images in a typical radiology department are represented in digital form. This includes images that have been captured using digital imaging modalities such as computed tomography and magnetic resonance imaging as well as images that have been digitally converted from film originals as in computed radiography. To provide economical storage of such images and to allow for their efficient transmission over various networks, it becomes necessary to consider digital image compression techniques. In this article, the fundamental concepts of several popular reversible and nonreversible image compression schemes are reviewed. In addition, the performance of the schemes in terms of compression ratio and reconstructed image quality as applied to medical diagnostic images is investigated.

Diagnostic Imaging↗

PubMed1991

Differential interactions between benzodiazepines and the dihydropyridines, nitrendipine and Bay K 8644.

The effects of the dihydropyridine calcium antagonist, nitrendipine and the calcium channel activator, Bay K 8644, have been compared on the anaesthetic, ataxic and anticonvulsant effects of benzodiazepines. Possible interactions between the peripheral benzodiazepine receptor antagonist, PK11195, and the classical benzodiazepines were also examined. Nitrendipine considerably potentiated the anaesthetic effects of benzodiazepines and increased their ataxic effects but had no effect on the anticonvulsant actions. Clonazepam did not produce anaesthesia, at doses up to 1 g kg-1 or when given with nitrendipine. When given alone, nitrendipine did not cause general anaesthesia. Nitrendipine did not appear to alter the metabolism of midazolam. The calcium channel activator, Bay K 8644, reduced the anaesthetic potency of midazolam and, when given alone, produced ataxia. It did not significantly alter central concentrations of midazolam. The "peripheral" benzodiazepine antagonist, PK11195, did not affect the ataxic or anaesthetic actions of benzodiazepines. These results suggest that dihydropyridine-sensitive calcium channels may be more important to the general anaesthetic than to the anticonvulsant actions of benzodiazepines. The "peripheral" benzodiazepine site did not appear to play a role in either of these properties.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗