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Biomedical subjects

J Hardie

Publications and source records attributed to J Hardie.

112 records · Page 7Linked to original sources
PubMed1968

Regulation of starch biosynthesis in plant leaves: activation and inhibition of ADPglucose pyrophosphorylase.

The ADPglucose pyrophosphorylases of 7 plant-leaf tissues were partially purified and characterized. In all cases the enzymes showed stability to heat treatment at 65 degrees for 5 minutes in the presence of 0.02 m phosphate buffer, pH 7.0. The leaf ADPglucose pyrophosphorylases were activated 5 to 15-fold by 3-phosphoglycerate. Fructose-6-phosphate and fructose 1, 6-diphosphate stimulated ADPglucose pyrophosphorylase to lesser extents. The A(0.5) (conc of activator required to give 50% of the observed maximal activation) of 3-phosphoglycerate for the barley enzyme was 7 x 10(-6)m while for the sorghum enzyme it was 3.7 x 10(-4)m. Inorganic phosphate proved to be an effective inhibitor of ADPglucose synthesis. The I(0.5) (conc of inhibitor that gave 50% inhibition of activity for the various leaf enzymes varied from 2 x 10(-5)m (barley) to 1.9 x 10(-4)m (sorghum). This inhibition was reversed or antagonized by the activator 3-phosphoglycerate. These results form the basis for an hypothesis of the regulation of leaf starch biosynthesis.

Glucosyltransferases↗
PubMedDate not supplied

Ultrastructural contributions to the study of morphological differentiation in malignant mixed (pleomorphic) tumors of salivary gland.

Ultrastructural studies of pleomorphic adenoma have shown a coordinated differentiation of luminal epithelial and modified myoepithelial cells with the latter cells related to processes resulting in the myxochondroid stroma. Five examples of various histologic types of malignant mixed tumor of parotid origin were examined by electron microscopy to see if underlying patterns of tumor cell differentiation and organization matched those of pleomorphic adenoma. Whether they were intracapsular tumors (with or without identifiable pleomorphic adenoma), carcinomas ex pleomorphic adenoma, or a true malignant mixed tumor, all lesions had cell types and organizations either identical to those in pleomorphic adenoma or, as in less-differentiated examples, displayed features suggesting origin from luminal cells, myoepithelial cells, or both. Even the chondroid cells in the true malignant mixed tumor expressed ultrastructural features indicating their epithelial derivation. On the basis of these findings, some alterations to the classification and terminology of the subtypes of malignant mixed tumor are suggested.

Adenoma, Pleomorphic↗
PubMedDate not supplied

The Miswak as an aid in oral hygiene.

The Miswak is chewing stick used throughout the Middle East. In this article for FDI World, Drs. John Hardie and Khaled Ahmed, both practitioners in Saudi Arabia, review the literature on its mechanical cleansing action and the chemicals within its fibres which may be more effective in promoting oral health. They speculate that, since the plaque removing properties of the miswak and conventional toothbrush are similar, the beneficial effects of the toothbrush may also depend less upon the mechanical efficiency of its bristles and more upon the chemical constituents of the toothpaste.

Dental Devices, Home Care↗