2-micron vectors containing the Saccharomyces cerevisiae metallothionein gene as a selectable marker: excellent stability in complex media, and high-level expression of a recombinant protein from a CUP1-promoter-controlled expression cassette in cis.

We have constructed 2-micron-based yeast expression vectors containing a copy of the metallothionein (CUP1) gene of Saccharomyces cerevisiae as a semi-dominant, selectable marker. When used for the expression of the thrombin inhibitor hirudin, originally derived from the leech Hirudo medicinalis, these vectors displayed the following characteristics. (1) In the presence of copper salts, they were mitotically more stable than similarly designed control vectors lacking the CUP1 gene. In copper-sensitive host strains, the apparent plasmid stability was 100%, even in complex media and during fed-batch fermentation for an extended period of time. (2) Use of the CUP1-stabilized plasmids improved the production of hirudin by both copper-sensitive and copper-resistant hosts. The highest hirudin titers were obtained with a delta CUP1 host. (3) Copper selection resulted in a moderate increase in average plasmid copy numbers (up to two-fold) as assessed by measuring hirudin expression from a constitutive promoter (GAPFL). This effect was most noticeable if the vector showed an asymmetric segregation pattern (i.e., high rates of plasmid loss in the absence of copper). (4) The CUP1 marker proved particularly useful in combination with a CUP1-promoter-controlled expression cassette on the same plasmid. In such a set-up, the rates of transcription of the heterologous protein and that of the selectable marker are tightly linked. Therefore, an increase in selective pressure directly provokes an increase in product yields. In a copper-sensitive host strain, this plasmid design allowed for the production of very high amounts of biologically active hirudin. Our results clearly establish the utility of the CUP1 marker in the construction of stable yeast expression vectors.

Determination of acid phosphatase in cultivation medium using asymmetrical flow field-flow fractionation.

Highly glycosylated proteins and proteins larger than 100,000 Da are difficult to analyze in complex media with standard liquid chromatography techniques. Asymmetrical flow field-flow fractionation is a simple bio-compatible method for such analysis which can also be used for on-line monitoring. A method for determination of acid phosphatase (EC 3.1.3.2), molecular weight 1,000,000, produced by a recombinant DNA yeast strain is presented.

Flow injection analysis and in-line biosensors for bioprocess control: a comparison.

Miniaturization will unify the different approaches chosen for the application of biosensors in bioprocess control. The most versatile system, which in our opinion is flow injection analysis will be the method of choice for the introduction of biosensors in bioprocess control. A lot of experience will be gained for the future development of miniaturized total chemical analysis systems.

[Cardiomyopathy after osteosarcoma treatment: a contribution to the cardiotoxicity of adriamycin]. / Kardiomyopathie nach Osteosarkombehandlung: ein Beitrag zur Kardiotoxizität von Adriamycin.

The frequency and severity of clinical and subclinical heart damage were studied in patients who had been treated with adriamycin (ADR) as part of the Cooperative Osteosarcoma Studies (COSS). The study charts of 785 patients from 63 participating institutions were reviewed: The overall incidence of drug-induced congestive heart failure was 2.2% (17 cases, 5 fatal). Late left ventricular function was studied in 29 tumor free survivors 81 +/- 41 month after treatment with 342 +/- 113 mg/m2 ADR. A detailed history and physical exam for signs of overt heart disease were obtained. M-mode echocardiography (ECHO, 29 cases) with evaluation of the fractional shortening rate (FS) and radionuclide ventriculography (RNV, 18 cases) with determination of the systolic ejection fraction at rest (EF) were used to screen for subclinical cardiac disease. Impaired cardiac function leading to pathological values was documented in close to one half of these patients. The frequency and severity of clinical and subclinical heart damage increased with cumulative adriamycin and time since cessation of anthracycline therapy.

Flow injection analysis and biosensors: applications for biotechnology and environmental control.

Our experience in industrial bioprocess monitoring and environmental control let us develop a concept for biosensor research which distinguishes itself from other, more popular, approaches. Biosensors must improve and/or simplify existing state-of-the-art analysis systems. Only the parallel development of biosensors and their complementary metrology leads to industrially sound solutions. The combination of flow injection analysis with immobilized enzymes in the form of enzyme columns is already used today for the solution of on-line analytical problems in bioprocesses and environmental control.

A flow injection analysis system for fermentation monitoring and control.

An automated analysis system for on-line fermentation monitoring is presented. The modular system consists of an in-line sterilizeable crossflow microfilter, a selection valve that allows injection of sample or standards, a degassing unit, a dilution module, and a FIA manifold with a spectrophotometric UV/VIS detector. In the dilution module samples are conditioned and diluted depending upon concentration of analyte and the working range of the analyzer. Methods for the monitoring of glucose, ethanol, ammonia and phosphate are described. Results from the monitoring of glucose and their use in fermentation control are presented. The maximal analysis frequency is 30 samples per hour including the dilution of 1 : 200. Detection limits are 5 mg/L for ethanol and glucose, 1 mg/L for phosphate and 50 mg/L for ammonia.