A micro-focus X-ray diffractometer was applied to a ground section of sialolith, and localization of brushite and whitlockite was found. The sialolith was composed of a central core of organic material and a layered cortex of mineral components. The major component of the mineral cortex is apatite. Brushite and whitlockite locate independently at the surface layer of the cortex.

The degree of crystallinity of the inorganic components in bovine enamel during maturation was calculated and was compared with the degree of calcification. The process of calcification was quantified using monochromatic X-ray microradiography, and the extent of crystallization was analyzed using an X-ray microdiffraction method.The results showed two notable phenomena. (1) that calcification continued for a short time after the eruption of the tooth, and (2) that the crystallization of the inorganic components was delayed in relation to the process of calcification before eruption, but caught up and progressed rapidly after eruption.

Scanning electron microscopy of a submandibular sialolith showed octahedral and dipyramidal crystals located at the surface layer of cortex. The crystal habits observed were consistent with those of a tetragonal crystal system. X-ray microdiffraction revealed the presence of weddellite. The origin of weddellite within the calculus remains to be determined.

No abstract

The effect of twin gestation on carbohydrate metabolism was evaluated using a 75 g oral glucose tolerance test (75 g OGTT). A 75 g OGTT was performed in 63 twin gestations and 3 791 singleton gestations during the third trimester. Plasma glucose concentrations were measured in the pregnant women under fasting conditions as well as 30 min, 1 h, and 2 h after ingestion of glucose (75 g oral load), and serum insulin concentrations were measured in fasting and 30 min post-ingestion samples. Women with twin gestations showed significantly lower plasma glucose concentrations during fasting and 30 min after the glucose load in the samples taken than those with singleton gestations. No significant difference in serum glucose concentrations was found in the other specimens. There were no cases of gestational diabetes mellitus in our study. Although women with twin gestations demonstrated lower plasma glucose concentrations than women with singleton gestations, the difference observed was subtle. We could not find any significant differences in these plasma glucose values as used to define a pathologic OGTT between twin and singleton pregnancies, with the exception of the fasting value.