Data collected in a national external quality assessment program for free thyroxine (fT4) and free triiodothyronine (fT3) were analyzed to evaluate the performance of 10 method/kits with 26 control samples distributed to approximately 170 laboratories. The control materials were normal serum pools, pooled sera supplemented with thyroid hormones, a pregnancy serum pool, serum pooled from patient...

Kinetic studies on hydrogen peroxide-induced inactivation of mutant formate dehydrogenase from Pseudomonas sp. 101 (PseFDH Cys255Ala) suggest a simple bimolecular mechanism for enzyme reaction with the inactivation agent. In the excess of hydrogen peroxide, the decrease in enzyme activity follows first-order kinetics. Therefore, the first-order effective inactivation kinetic constants determine...

Metabolic engineering studies have generally focused on manipulating enzyme levels through either the amplification, addition, or deletion of a particular pathway. However, with cofactor-dependent production systems, once the enzyme levels are no longer limiting, cofactor availability and the ratio of the reduced to oxidized form of the cofactor can become limiting. Under these situations, cofa...

HeLa cells were exposed to formaldehyde and its metabolic derivatives, methanol, formic acid, and acetaldehyde, to investigate that the toxicity of formaldehyde is not caused by the chemical group. After 1 h of treatment with formaldehyde, mitochondrial assays showed that low concentrations (e.g. 10 μmol/L) of formaldehyde promoted growth of the HeLa cells, while higher concentrations (e.g. ≥62...

In addition the enzyme catalyzes the oxidation of NADH by 0 2 . The stoichiometry of the first reaction is proved by the formation of the amount of NADH which under anaerobic conditions exactly corresponds to the amount of formate used. In this reaction NAD is replaceable by a large number of redox dyes. For the second reaction the stoichiometry is proved a) kinetically by the relation of the v...

Abstract: Classical cost efficiency (CE) measurement models require exact and accurate knowledge of the input and output values for each decision making unit (DMU). However, the observed values of the input and output data in real-world problems are often imprecise or vague. In recent years, fuzzy data envelopment analysis (DEA) has been successfully used to deal with imprecise or vague data in...

P aediatricians are frequently asked to see children who cause concern because of their slow growth or development. In this situation, despite the absence of any specific abnormal signs, thyroid function tests are commonly requested. They are nearly always normal. We describe three patients, where abnormal results led to erroneous treatment for thyrotoxicosis. These patients had a diagnosis of ...

CO2 fi xation is a potential technology for the realization of photocatalytic CO2 reduction and synthesis of organic compounds from CO2 as a starting material. Many studies of CO2 fi xation or utilization have investigated ultra-visible light induced photocatalysis on semiconductors such as titanium dioxide1), silicon carbide1) and strontium titanate2) in heterogenous aqueous media. Biological ...

CLINICALCHEMISTRY, Vol. 34, No. 3, 1988 599 2. Stockigt JR, De Garis M, Barlow JW. “Unbound analog” methods for free T4: a note of caution. N Engi J Med 1982;307:126. 3. De Nayer P, Malvaux P, Beckers C. Familial dysalbuminemic hyperthyroxinemia (FDH): inadequacy of the “analog” methods for assaying free T4 levels. Eur J Nuci Med 1984;9:284-5. 4. Stockigt JR, Dyer SA, Mohr VS. White EL, BarlowJ...