Prevalence of middle mesial and middle distal canals in mandibular molars in an Egyptian subpopulation using micro-computed tomography.

OBJECTIVES: To study the prevalence of middle mesial and middle distal canals in permanent mandibular molars in Egyptian subpopulation using micro-computed tomography. MATERIALS AND METHODS: Two hundred and forty extracted mandibular permanent molars of Egyptian patients were scanned using micro-computed tomography, then the images were reconstructed to allow for the detection of the middle mesial (MM) and middle distal (MD) canals of the molars examined. The path of each extra canal was studied to determine the configuration of each canal. Data were analyzed statistically using the Chi-square test with a level of significance set at P< 0.05. RESULTS: The evaluation of three-dimensional (3D) images of this study showed that no significant difference was found between the percentage of MM (27.5%) and MD canals (22.5%) (P = 0.2064); however, there was a significant difference between the percentage of teeth having both extra canals (10%) and teeth having only one of these canals (P < 0.05). The confluent configuration (71%) was significantly higher than the other configurations (P < 0.05). CONCLUSION: A higher percentage of MM canal was detected followed by the MD canal. The least significant was both canals occurring within the same molar. The percentage of the confluent configuration was the highest. The apt knowledge of the variations of the root canal system anatomy and the respect of the discrepancies associated with diverse demographic areas will ensure the proper management of each tooth with endodontic involvement and its long-term success.

[Effect of the soft laser on gingival connective tissue. I--Effect on fibroblasts. Histoenzymology and electron microscopy study]. / Effet du soft-laser sur le tissu conjonctif gingival. I--Effet sur les fibroblastes. Etude d'histoenzymologie et de microscopie électronique.

The effect of soft-laser upon human gingival fibroblasts was studied after an initial biopsy followed by irradiation and numerous biopsies performed 5 mn, 15 mn, 1 hour and 24 hours after irradiation. In addition, control biopsies were performed in the same way on a non-irradiated gingival area. One hour after irradiation and up to 24 hours later, the enzymatic activities of the fibroblasts were obvious: oxidative enzymes, leucine aminopeptidase, and considerable Brachet's test highly positive (RNA). By transmission electron microscopy were changes were found in these fibroblasts. They were more numerous and their cytoplasmic organelles were increased (mitochondria, rough endoplasmic reticulum). An abundant granular material as well as collagen fibrils were accumulated along their cytoplasmic membrane. On the whole, from the 1st hour on following irradiation by soft-laser a stimulation of metabolic activity of the fibroblasts (oxidative activities, proteic synthesis) was observed with increased production of collagen.

[Effect of the soft laser on gingival connective tissue. II--Effect on wound healing. Optical microscopy, histoenzymology and electron microscopy studies]. / Effet du soft-laser sur le tissu conjonctif gingival. II--Effet sur la cicatrisation. Etude en microscopie optique, histoenzymologie et microscopie électronique.

The effect of soft-laser upon cicatrization of the gum was studied in 14 patients. After the initial biopsy, control biopsies were performed on the same patients in non-irradiated gums. In the absence of inflammation, cicatrization took place in a similar manner in the irradiated and control tissues. After an early vascular growth, connective cylinders occurred, accompanied by an increase of enzymatic activity) (oxidative enzymes, leucine aminopeptidase, alkaline phosphatase). Then, the scar was formed of longitudinal bundles. The laser induced an earlier cicatrization (14th day) than in the controls (21st day). The presence of inflammation in the gum delayed cicatrization and often promoted cheloid scars with abnormal anastomosing connective bundles. In this case also, irradiation by soft-laser was followed by a quicker and better cicatrization.

Liver monoamine oxidase (MAO) in liver homogenate of mice infected with Schistosoma mansoni and effect of certain therapeutic agents.

MAO activity in liver homogenate of mice infected with Schistosoma mansoni was determined from the second till the 14th week following infection. Significant diminution of MAO activity was noticed starting from the sixth week following infection, reaching its lowest value at the eighth week, obviously denoting progress of hepatic fibrosis. Treatment of the infected, animals with four different antischistosomal agents, tarter emetic, stibophen, niridazole and hycanthone, resulted in an improvement of the enzyme level to an almost normal value. This may indicate the ease with which the lesions in the liver including fibrosis recover when the infection is successfully treated.

Functional capacity of the tryptophan-niacin pathway in the premenarchial phase and in the menopausal age.

Studies on the interrelationship between female hormones associated with reproduction and the vitamin B6-dependent enzymes along the kynurenin pathway of trytophan metabolism were carried out in girls with an age less, and more than 10 years (just before the onset of the first menstrual cycle), and in postmenapausal women with and without relative (excess) production of estradioll from the adrenal cortex. It is found that most of the determined metabolites are retained by the girls with age less than 10 years after tryptophan loading without and with vitamin B6 supplementation. Estradiol from either the ovaries (in girls just before menarch), or the adrenal cortex-in postmenopausal women with relative (excess) production of this hormone-interferes with the further degradation of 3-hydroxyanthranilic acid. However, this interference could be completely restored by vitamin B6 supplementation. The extra presence of a partial impairment in the kynureninase enzyme is also suggested in these postmenopausal women. In the latter case, this enzymatic activity could be partially resored by vitamin B6 supplementation. On the contrary, the enzymes: kynureninases and adrenocortical estradio. Pyridoxine supplementation partially corrected the inhibition especially that of 3-hydroxykynurenine transaminase enzyme.