Abstract: A channel or chamber device having means for inhibiting flow of aqueous medium therein after the channel or chamber has been filled with aqueous medium. The device has a channel or chamber with a sample intake port at one end and an exhaust port at the other end. A restricted or reduced size chamber portion having reduced dimension (height, cross-sectional area or diameter) toward the exhaust port is provided with a water-expandable polymer in the restricted or reduced size chamber portion. The water-expandable polymer inhibits flow or forms a seal in the exhaust port when the polymer is contacted with an aqueous medium. The channel or chamber device having means for inhibiting flow of aqueous medium therein is especially adaptable to capillaries used in medical diagnostic measuring devices which contain an analytical reagent for biological fluids, such as saliva and plasma.

Abstract: Oxygen-independent methods, systems and devices for the enzymatic colorimetric assay and detection of biochemical analytes. Two systems are described, both of which produce less than one equivalent of dye per equivalent of substrate, maintaining dye concentrations in the range where Beer's law predicts a linear color-concentration relationship. One system produces an analog color signal from an analog analyte input, the other system produces a digital color signal from an analog analyte input.

Abstract: The invention provides a reagent system for the enzymatic determination of an oxidizable substrate in a fluid sample; the system includes an active amine trap for inactivating high concentrations of aldehyde and ketone oxidation products comprising a combination of at least one primary amine and at least one alpha-effect amine. An example of the oxidizable substrate is alcohol.

Abstract: A system for quantitative colorimetric analysis of biological fluids or organic compounds, including NAD(P)H, or a substrate of an enzyme which reacts with the formation or consumption of NAD(P)H. Concentrations of organic substrates for example alcohol, cholesterol, uric acid, in a biological fluid such as saliva, blood or urine may be determined. The system gives a digital reading of the organic material the concentration which is sought to be determined; the concentration of NAD(P)H is determined by a color change or color "signal" when the NAD(P)H is above a threshold concentration and by the absence of a color signal when the concentration of NAD(P)H is below the threshold concentration. The system includes a chromogen, an electron-accepting reactant which, until exhausted, prevents a visible color change due to accumulation of reduced chromogen, and a catalyst.

Abstract: An assay system useful for the determination of NAD(P)H, NAD(P), or a substrate of an enzyme which reacts with the formation or comsumption of NAD(P)H. Concentrations of organic substrates for example alcohol, cholesterol, uric acid, in a biological fluid such as saliva, blood or urine may be determined. The system includes a diaphorase which catalyzes a NAD(P)H-dependent reduction of a chromogen to cause a visible color change; this color change is indicative of the concentration sought to be determined. The system includes a chromogen which is a first substrate for the diaphorase which causes a color change when reduced by NAD(P)H, and a second substrate which is a competing substrate for the diaphorase; the competing substrate is irreversibly reduced by the diaphorase. The system is capable of measuring colorimetrically without dilution concentrations of organic compounds in biological fluids which previously could not be measured in such concentration.

Abstract: A novel highly effective prokaryotic expression system is exemplified specifically by being used to produce the useful enzyme .beta.-glucuronidase (BG). This system uses a hybrid plasmid comprising BG gene promoter DNA. The level of expression of BG by an E. coli K-12 derivative host is in the 50% of total cellular protein range. The invention expression system also can be used to express other useful proteins, as disclosed herein.

Abstract: Hybrid useful proteins are prepared by a novel biological system comprising a prokaryotic host transformed with novel hybrid plasmids' .beta.-glucuronidase (BG) gene DNZ and the desired protein gene DNA. Specifically exemplified are plasmids which comprise BG gene DNA and protein A DNA. E. coli K-12 derivative hosts transformed with plasmid pBG3-2.DELTA.n express >60% of the desired fusion protein having protein A-like biological activity. Other useful proteins can be expressed via the elegant highly efficient expression system of the subject invention.

Abstract: A novel highly effective prokaryotic expression system is exemplified specifically by being used to produce the useful enzyme .beta.-glucuronidase (BG). This system uses a hybrid plasmid comprising BG gene promotor DNA. The level of expression of BG by an E. coli K-12 derivative host is in the 50% of total cellular protein range. The invention expression system also can be used to express other useful proteins, as disclosed herein.

Abstract: Hybrid useful proteins are prepared by a novel biological system comprising a prokaryotic host transformed with novel hybrid plasmids' .beta.-glucuronidase (BG) gene DNA and the desired protein gene DNA. Specifically exemplified are plasmids which comprise BG gene DNA and protein A DNA. E. coli K-12 derivative hosts transformed with plasmid pBG3-2.DELTA.N express >60% of the desired fusion protein having protein A-like biological activity. Other useful proteins can be expressed via the elegant highly efficient expression system of the subject invention.

Abstract: A method of preventing the precipitation of proteins, such as hormone preparations, within drug delivery systems that depend on the fluidity of the infusate for proper function. A polyol, such as glycerol, is mixed with the protein solution prior to the introduction of the solution into the drug delivery system. The polyol is added in amount sufficient to prevent precipitation of the protein during long-term storage in the drug delivery device. According to one form of usage, the protein-polyol solution is injected to the pressurized drug storage reservoir of an implanted infusion pump by injection through the patient's skin. As the solution is discharged from the delivery device by the constant pressure exerted upon the storage chamber, its low rate of flow is controlled by a restricted fluid passage. The solution is conveyed to an infusion site and diluted by the blood stream.