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Biomedical subjects

S El-Masry

Publications and source records attributed to S El-Masry.

11 recordsLinked to original sources
PubMed2005

Interleukin (IL)-4, IL-10, IL-18 and IFN-gamma cytokines pattern in patients with combined hepatitis C virus and Schistosoma mansoni infections.

Schistosoma mansoni infection is characterized by a strong T-helper type 2 (Th2) cell-associated immune response, but in the case of viral infection, it is associated with interferon-gamma (IFN-gamma) increase and induction of Th1 immune response. Few data are available about the immune response of cases infected with combined hepatitis C virus (HCV) and schistosomiasis. Thus, the investigation of the cytokine pattern in patients coinfected with both HCV and Schistosoma mansoni was our rationale. This study included four patient groups: Group 1 included 20 patients infected with chronic HCV, Group 2 included 15 patients infected with schistosomiasis alone, Group 3 included 20 patients with chronic HCV and schistosomiasis and Group 4 included 15 healthy control individuals with matched age and sex. Serum levels of IFN-gamma, interleukin (IL)-4, IL-10 and IL-18 were measured in all groups by enzyme-linked immunosorbent assay. The results showed that the patients infected with HCV had significantly higher serum levels of IFN-gamma and IL-18 compared with the controls and with the patients with schistosomiasis and coinfection (P < 0.001). On the other hand, serum levels of IL-4 and IL-10 were significantly higher in patients with schistosomiasis and coinfection compared with the control group (P < 0.001 and 0.0001, respectively) and with the HCV patients (P < 0.05 and P < 0.001, respectively). A significant increase in serum levels of IL-4 and IL-10 was also found in HCV patients compared with the control (P < 0.05). Schistosomiasis appears to induce a Th2 cytokine profile, with increase in serum levels of IL-4 and IL-10, even in the presence of HCV coinfection. In conclusion, schistosomiasis may downregulate the stimulatory effect of HCV on Th1 cytokines and this may lead to the chronicity of HCV infection in coinfected patients.

Adult↗
PubMed1980

Colorimetric and spectrophotometric determinations of hydrastis alkaloids in pharmaceutical preparations.

Hydrastine, canadine, and berberine were determined by the acid-dye technique. At pH 5.6, both the tertiary and the quaternary hydrastis alkaloids formed ion-pairs with bromcresol purple. The liberated hydrastine and canadine from the alkaloid-dye complexes were determined spectrophotometrically in the presence of berberine by the three-wavelength method of analysis. However, berberine could not be assayed successfully by this method due to significant partitioning in the aqueous phase during extraction. At pH 7.2, only berberine could ion-pair with bromcresol purple to form a chloroform-extractable complex. Consequently, the berberine content was analyzed selectively through the colorimetric determination of the combined dye at 580 nm. The suitability of the proposed methods was examined through the analyses of synthetic mixtures of hydrastis alkaloids and samples of hydrastis tincture and liquid extract. Percentage recoveries were 98.2-101.4 for the synthetic mixtures and 98.4-101.7 for the tincture and liquid extract spiked with berberine.

Alkaloids↗
PubMed1980

New spectrophotometric assay for pilocarpine.

A quick method for the determination of pilocarpine in eye drops in the presence of decomposition products is described. The method involves complexation of the alkaloid with bromocresol purple at pH 6. After treatment with 0.1N NaOH, the liberated dye is measured at 580 nm. The method has a relative standard deviation of 1.99%, and has been successfully applied to the analysis of 2 batches of pilocarpine eye drops. The recommended method was also used to monitor the stability of a pilocarpine nitrate solution in 0.05N NaOH at 65 degrees C. The BPC method failed to detect any significant decomposition after 2 h incubation, but the recommended method revealed 87.5% decomposition.

Indicators and Reagents↗
PubMed1979

Colorimetric and spectrophotometric determination of total and non-phenolic alkaloids in ipeca and its formulations.

A simple method, requiring no chromatographic separation, is presented for the determination of the total and non-phenolic alkaloids in ipeca and its preparations. The complex formed between the alkaloid and methyl orange at pH 5.0 is extracted with chloroform and treated with 0.1N NaOH. The liberated dye, determined at 460 nm, is a measure of the total alkaloids. The chloroform phase remaining is treated with 0.1N H2SO4, and the acid extract is measured at 283 nm for the non-phenolic alkaloids, calculated as emetine. The proposed method was successfully applied to samples of ipeca powder, ipeca tincture, and 3 British Pharmaceutical Codex mixtures containing ipeca tincture, namely, ipecacuanha mixture, pediatric; ipecacuanha and ammonia mixture, pediatric; and belladonna and ipecacuanha mixture, pediatric. The proposed method compares favorably with the Egyptian Pharmacopoeia, British Pharmacopoeia, and USP methods and has a relative standard deviation of 1.54%. The present procedure is less time-consuming and requires about 45 and 90 min for the assay of ipeca tincture and powder, respectively. Only a small sample (0.2 mL tincture of 1.0 g powder) is required.

Ammonia↗
PubMed1978

Instability of digoxin in acid medium using a nonisotopic method.

A selective nonisotopic assay was used to investigate the digoxin hydrolysis rates at 37 +/- 0.1 degrees over the pH 1.1--2.2 range. The colorimetric method adopted is based on the use of a xanthydrol reagent after extraction with chloroform. The spectrofluorometric method specified in the dissolution test for digoxin tablets was nonspecific because of digoxigenin interference. Digoxin hydrolysis followed specific acid hydrolysis, and K values of the apparent first-order reaction varied from 0.0357 to 0.0027 min-1 over the pH range used. The effect of the dissolution medium on digoxin stability during the dissolution tests of the tablets also was studied. Water (the BP medium) and 0.6% HCl (the USP medium) were compared using the fluorometric method and the xanthydrol method. In the USP medium (pH 1.3), no hydrolysis was revealed by the fluorometric estimation whereas the xanthydrol method showed about 74% hydrolysis. In water, the two methods revealed no hydrolysis. The extent of hydrolysis after 1 hr in the USP medium was studied using three brands of digoxin tablets of differing dissolution characteristics. The fast dissolving brand showed relatively more hydrolysis than the slow dissolving tablets.

Chemistry, Pharmaceutical↗
PubMed1978

Spectrophotometric determination of strychnine and brucine in liquid galenicals.

A rapid method is presented for determining strychnine and brucine in liquid galenicals. At pH 5.0, both strychnine and brucine are complexed with methyl orange. After treatment with 0.1N NaOH, the liberated alkaloids are determined spectrophotometrically, using the 2-wavelength method of analysis. The method has been successfully applied to the analysis of 4 batches of nux vomica tincture, nux vomica acid, and nux vomica alkaline mixtures. The method has a relative standard deviation of 0.52%.

Spectrophotometry, Ultraviolet↗
PubMed1977

Induction of HMG CoA reductase by the administration of 20,25-diazacholesterol.

This paper describes the direct examination of HMG CoA reductase activity in rats treated with 20,25-diazacholesterol. Conversion of acetyl CoA and HMG CoA to mevalonate increased to over 200% of control values in the microsomes and in the 12,000 g supernatant of liver homogenates after 5 days of treatment. The time course of induction coincided with the development of hypocholesterolemia. Animal weights, liver weights, and microsomal protein content did not vary significantly between animal groups. Incubations to which the compound was introduced in vitro in concentrations as great as 0.5 mM produced no significant difference from control incubations. Similar treatment of the animals with 7-ketocholesterol, a cholesterol derivative reported to repress HMG CoA reductase activity in tissue cultures, produced no appreciable difference in reductase activity or serum steroid levels in vivo.

Alcohol Oxidoreductases↗
PubMed1976

Determination of hyoscyamine in BPC mixtures.

The hyoscyamine contents of four BPC mixtures (containing either belladonna or hyoscyamus tincture) were determined using the acid-dye technique. A sample size of 10 ml was required. The mean percentage recovery of hyoscyamine ranged from 99.73 to 101.03 from three mixtures; from the magnesium trisilicate and belladonna mixture, it was 94.8. The effects of pH and adsorption on the extraction of the alkaloid-dye complex from the mixtures examined are discussed.

Aluminum Hydroxide↗