The effects of sugars and polyols on the thermal denaturation temperature, Tm, of acid-soluble collagen from calf skin were studied at pH 4.0 under atmospheric pressure as well as high pressures up to 4,000 atm. Addition of these compounds invariably raised Tm with increases in their concentration over the whole range of pressure. The extent of stabilization by different sugars and polyols is discussed in terms of their different influences on the structure of water. The hydroxymethyl chain length of polyols and equatorial OH groups of the sugars were found to be decisive factors for their stabilizing effect on collagen structure. The similarity in their stabilizing effects on collagen and globular proteins suggests that our stabilization mechanism proposed for globular proteins can be essentially extended to fibrous proteins: such protein stabilization would be dominantly mediated through a preferential hydration of protein, originating in the water-structure-making character of sugars and polyols.

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SummaryA theoretical study was made on the dynamic behavior of a single-vessel continuous fermentation subject to a growth inhibition a t high concentration of the rate limiting substrate. Phase plane plotting and stability analysis showed three steady states to exist; namely, a "washout" state, a nontrivial stable state, and an unstable state. Whether the system attains a nontrivial steady state or is to be washed-out depends upon the initial values of the cell and/or substrate concentration(s). Since this property is a characteristic feature of the present system, an experimental procedure was suggested to insure a stable operation in practice.

The expression levels of the Wilms' tumor gene WT1 were examined in 34 primary thyroid cancers (24 papillary, 5 follicular, 1 anaplastic, and 4 medullary carcinomas), 17 thyroid follicular adenomas, and 6 normal-appearing thyroid tissues using quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR). In 33 of 34 thyroid cancers, the WT1 mRNA was expressed at levels ranging from 5.0 × × × ×10−2 levels (WT1 expression level in K562 leukemic cells was defined as 1.0). The WT1 mRNA expression levels were significantly higher than those in either thyroid follicular adenomas (P < < < <0.001) or normal-appearing thyroid tissues (P < <

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