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Biomedical subjects

A Shalaby

Publications and source records attributed to A Shalaby.

8 recordsLinked to original sources
PubMed1999

Changes in intestinal endocrine cells in the mouse after unilateral cervical vagotomy.

The effect of right or left unilateral cervical vagotomy on the intestinal endocrine cells was studied in 23 mice at 2 and 8 weeks after operation, respectively. The results were compared with that from 10 sham operated mice. Various types of endocrine cells in duodenum and proximal colon were detected by immunohistochemistry and quantified by computerized image analysis. In mouse duodenum, chromogranin-, CCK/gastrin-, GIP- and somatostatin-cells were significantly decreased at 2 weeks after right vagotomy, but returned to the control levels at 8 weeks. Serotonin-cells were reduced at both 2 and 8 weeks after right vagotomy. The amount of the duodenal endocrine cells did not change after left vagotomy with the exception of secretin-cells, which were diminished at 8 weeks after both right and left vagotomy. In the proximal colon, chromogranin-cells were also decreased at 2 weeks after right vagotomy. Serotonin-cells were reduced at 8 weeks after left vagotomy but not right vagotomy. There was no significant difference between the unilaterally vagotomized and the sham operated mice with regard to PYY- and glucagon-cells. It was concluded that vagotomy affected the intestinal endocrine cells in mouse. The influence was more pronounced in the small intestine than the proximal colon. The right vagus nerves seemed to exert more effect on the intestinal endocrine cells than the left ones.

Animals↗
PubMed1999

Effects of unilateral cervical vagotomy on antral endocrine cells in mouse.

The present study was carried out to investigate the effect of unilateral cervical vagotomy on the antral endocrine cells in mouse. Fifty-four mice were randomly divided into three groups, 18 in each, for left or right cervical vagotomy, or sham operation as controls. The animals were sacrificed 2, 4, and 8 weeks after the operation, respectively. Chromogranin-, gastrin/CCK-, serotonin-, and somatostatin-cells were detected by immunohistochemistry and quantitated by computerised image analysis. The results showed that the number of chromogranin-cells was decreased in both left and right vagotomized mice after 4 weeks and remained at the same level after 8 weeks. The numbers of gastrin-, serotonin- and somatostatin-cells did not change after right vagotomy. However, the numbers of gastrin- and somatostatin-cells were decreased after left vagotomy, whereas no change was found in serotonin-cells. Endocrine cells with vacuolated cytoplasm and pyknotic nuclei were also observed during the course of time. The alteration in the antral endocrine cells observed in this study seemed to be dynamic and depended on the observation time after the operation as well as the denervated branches of the vagus nerve. This may explain, at least partially the contradictory results obtained earlier by different investigators.

Animals↗
PubMed1991

[HPC purity tests for caffeine, theophylline and theobromine].

After giving a survey of the literature of the HPLC methods for the determination of caffeine, theophylline and theobromine two methods are presented for their purity test, i.e. their detection in each other at the trace level. In the reversed-phase system the stationary phase was C18-silica and the 2:3 mixture of methanol and water was used as the eluent at a detection wavelength of 254 nm. The k' values for theobromine, theophylline and caffeine are 0,25, 0,62 and 1,12, respectively. This system enables the detection of 0,2% of theobromine and 0,1% of theophylline in caffeine and 0,2% of caffeine in theobromine or theophylline. In the normal phase system silica was used as the stationary phase while the eluent was 85:15:0,05 mixture of chloroform, dioxane and formic acid. The wavelength of the detection was 273 nm. The k' values of caffeine, theobromine and theophylline are 1,5 4,0 and 5,6, respectively. This system also enables the detection of 0,1% of theophylline and theobromine in caffeine or 0,2% of caffeine in the former. Theophyline and theobromine can be detected in each other at the 0,1% level.

Caffeine↗
PubMed1989

Ion-pair HPLC study of sulfonamides, barbiturates and antiphlogistic acids on a dynamically modified silica gel stationary phase.

The behaviour of some groups of acidic drugs (barbital derivatives, sulfonamides and antiphlogistic acids) was studied with a reversed-phase ion-pair HPLC method. A methanol-water-posphate buffered (pH = 7) mobile phase containing various concentrations of cetrimide was applied on a silica gel column. The correlations between the migration and the chemical structure within the different groups of compounds are discussed. Monofunctional benzene derivatives were utilized to investigate the influence of the various functional groups in this system on the retention.

Anti-Inflammatory Agents↗
PubMed1989

Indirect potentiometric titration of reducing carbohydrates. I. Using alkaline potassium mercuric bromide solution and sulphide selective electrode.

Indirect potentiometric titration of reducing carbohydrates was developed, where sugar is heated with excess of alkaline Hg(II)-bromide solution. The end point is detected potentiometrically using sulphide selective electrode. The effect of the alkalinity of the reagent, the heating period in a boiling water bath and the presence of the sucrose were studied. The statistical analysis of the results obtained by this method reveals that it can be used with the same accuracy as the Fehling' method.

Bromides↗