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At least 55 records · Page 3Linked to original sources
PubMed1978

[Standardization of the methods of determining microorganism sensitivity to antibiotics. The importance of the method of interpreting the results in determining microorganism sensitivity to antibiotics].

The significance of the methods of the data interpretation for determination of the microbial sensitivity to antibiotics is discussed. A necessity for using semi-quantitative or quantitative systems of calculation instead of qualitative interpretation of the inhibition growth zone diameters is presented. It is shown that the use of the standard nutrient medium for determination of the antibiotic sensitivity in the laboratory practice may be a base for applying the methods of interpretation of the diffusion test data.

Agar↗
PubMed1978

[Survey of contamination of food by 3, 4-benzopyrene. I. Demonstration of a universal method of determination. Application to the determination in complete meals in food emporia].

A versatile spectrofluorimetric method is proposed for the determination of 3,4-benzopyrene in foods and biological material. Recording the emission spectrum allows a reliable identification, and determination at a 0,2 ppb level, with 85 p. 100 recovery and good reproductibility. The time required for analysis is decreased, if compared to existing methods. As a test of its reliability, results of a survey on 3,4-benzopyrene content in canteen meals are presented. The values obtain are very low, generally below 1 ppb; their significance is discussed.

Animals↗
PubMed1977

[Simultaneous determination of effective renal plasma flow and glomerular filtration rate using a double isotope technic--determination of the filtration fraction].

A method for the simultaneous determination of the effective renal plasma flow and of the glomerular filtration rate with the help of 131J-o-iodohippuric acid and 169Yb-DTPA using a double isotopic technique is described. Apart from this the method serves for the establishment of the filtration fraction. 40 patients with different clinical pictures (glomerulonephritis, pyelonephritis, cystic kidneys, stenosis of the renal artery) were examined. The clearance values established by us were in the areas characteristic for the clinical pictures. Pathological conditions could be established which are not yet characterized by an increase of the fixa of the urine in the serum. By the determination of the filtration fraction differential-diagnostically important insights are afforded. The examination is methodically simply to be performed and is of little stress for the patient. Therefore it seems to be suitable for the routine examination.

Glomerular Filtration Rate↗
PubMed1977

[Determination of urobilinoide concentration in the urine. New rapid method for clinical determination of urinary-urobilinoids using the Ehrlich-reaction].

A rapid method for quantitative determination of concentration of urobilinoids of fresh urine was developed. The method is based upon extraction of urinary urobilinoids using a mixture of acetic acid and ether and followed by the extraction of the ethereal phase with Ehrlich reagent and a solution of sodium acetate. Readings of absorbance from the absorption band of reaction products from urobilinoids and Ehrlich reagent are done. Performance of the rapid method: 2 ml urine + 10 ml ether + 2 ml acetic acid were thoroughly mixed for about 15 seconds. The ethereal extract was shaken after addition of 12 ml Ehrlich-reagent for 1 minute and 15 ml half-saturated sodium acetate solution were added. 0-3 minutes afterwards reading of absorption at 560 nm respectively filter Hg 578 nm. Photometer:mg/dl=29 X A578 nm, 1 cm -0,4. Spectrophotometer:mg/dl urobilinoids=13,7 X A560 nm X 1/d -0,22 (d=optical pathway). Photometrical determination of concentration of urobilinoid can also be done using table 1. Accuracy, reproducibility and specificity are fully satisfying for clinical use of the method.

Ethers↗
PubMed1976

The application of ferrihydroxamic complexes to photocolorimetric determination of drugs. Part 2: Quantitative determination of calcium pangamate (vitamin B15) and its calcium gluconate mixtures.

A quantitative method for calcium pangamate (Vitamin B15) and calcium gluconate determination, separately and in mixture, is proposed on the basis of the ferric hydroxamate procedure. The method may also be applied to the determination separately and in mixture, is proposed on the basis of the ferric of both preparations in mixture with various other substances which are not converted into lactone from in acid medium, and which the ferric hydroxamate procedure fails to develop.

Colorimetry↗
PubMed1978

[Determination of trace elements in dietary fats and emulsifiers by flameless atomic absorption spectrophotometry. 1. Determination of the ionogenically bound heavy metals copper, iron, nickel, zinc, lead and cadmium in dietary fats].

The knowledge of the trace metal contents in dietary fats is of considerable interest from the viewpoints of food hygiene and and storage stability. In the framework of the present paper, it is dealt with the determination of the ionogenically bound heavy metals copper, iron, nickel, zinc, lead and cadmium by means of flameless atomic absorption spectrometry (AAS). Problems related to trace analysis in dietary fats are discussed. Problem-oriented surveys in the form of tables inform about:--analytical conditions of the AAS technique,--metal contents as compared to data with the approved standard method,--contents of the ionogenically bound toxic trace elements cadmium, zinc and lead in samples of various dietary fats currently used in the German Democratic Republic.

Cadmium↗
PubMed1977

[Gas chromatographic determination of the volatile fatty acids (C1-C5) including lactic acid after conversion into their benzyl esters by phenyldiazomethane. Determination of the acids in silages (author's transl)].

A gas chromatographic method for the determination of the volatile fatty acids (C1-C5) including lactic acid is described. The acids are converted into their benzyl esters by means of phenyldiazomethane without previous purification of the reagent by distillation. The benzyl esters are well separated from the solvent as well as from one another. Silicone SE-30 is used as the stationary phase. An application of the method on silage acids is demonstrated.

Animal Feed↗
PubMed1977

The quantitative determination of metabolites of 6-mercaptopurine in biological materials. II. Advantages of a variable-wavelength HPLC spectrophotometric detector for the determination of 6-thiopurines.

The advantages of a variable-wavelength spectrophotometric detector for use in high-performance liquid chromatography are demonstrated with the detection of 6-mercaptopurine metabolites in cell extracts. 6-Methylthiopurines, unsubstituted 6-thiopurines and 6-thioguanines are most sensitively detected at 291, 322, and 342 NM, respectively. Compared with detection at 254 nm, the sensitivity at these wavelengths is about one to two orders of magnitude greater. Furthermore, in the 291-355-nm range, common purines, which are normally contained in cell extracts as free bases, nucleosides and nucleotides exhibit only minute absorbances and so do not interfere in quantitative determinations of 6-thiopurine compounds.

Animals↗
PubMed1975

Modification of the automated sequence determination as applied to the sequence determination of the Spirulina maxima ferredoxin.

The amino acid sequence of the Spirulina maxima ferredoxin was shown to be: H2N-Ala-Thr-Tyr-Lys-Val-Thr-Leu-Ile-Ser-Glu-Ala-Glu-Gly-Ile-Asn-Glu-Thr-Ile-Asp-Cys-Asp-Asp-Asp-Thr-Tyr-Ile-Leu-Asp-Ala-Ala-Glu-Glu-Ala-Gly-Leu-Asp-Leu-Pro-Tyr-Ser-Cys-Arg-Ala-Gly-Ala-Cys-Ser-Thr-Cys-Ala-Gly-Lys-Ile-Thr-Ser-Gly-Ser-Ile-Asp-Gln-Ser-Asp-Gln-Ser-Phe-Leu-Asp-Asp-asp-Gln-Ile-Gln-Ala-Gly-Tyr-Val-Leu-Thr-Cys-Val-Ala-Tyr-Pro-Thr-Ser-Asp-Cys-Thr-Ile-Gln-Thr-His-Gln-Glu-Glu-Gly-Leu-Tyr-COOH. The S. maxima ferredoxin is the first procaryote ferredoxin of the plant-algal type to be reported. A modification of the automated sequence determination of a peptide, which was extracted by the organic solvents used to remove excess reagents and the amino acid thiazoline, was utilized to complete the sequence of a 36 residue tryptic peptide.

Amino Acid Sequence↗
PubMed1975

Shared idiotypic determinants on B and T lymphocytes reactive against the same antigenic determinants. IV. Isolation of two groups of naturally occurring, idiotypic molecules with specific antigen-binding activity in the serum and urine of normal rats.

In the rat the major histocompatibility locus antigens are determined by the Ag-B locus. In the present article evidence is presented that the sera and urine of normal adult rats contain naturally occurring antibody-like molcules with reactivity to allogeneic Ag-B antigens. Such molecules can be shown to contain both antigen-binding capacity for the relevant antigens and the idiotypic markers signifying such specific reactivity. The molecules could be shown to be composed of two groups of molecules, one around 7S IgG in size and the other around 35,000 in molecular weight. Only the smaller molecules were found in the urine. From other data we know that the 7S molecules are produced by B lymphocytes and the 35,000-molecular-weight molecules by T cells. Purified natural anti-Ag-B factors, when inoculated into rabbits or chickens, lead to the production of specific anti-idiotypic antibodies that will selectively inactivate rat T lymphocytes with the capacity to react against the relevant Ag-B antigens while leaving other reactivity intact. We thus conclude that the present system allows the purification of naturally occurring idiotypic B- and T-cell products with antigen-binding specificity for further biochemical and functional analysis.

Animals↗
PubMed1976

Shared idiotypic determinants on B and T lymphocytes reactive against the same antigenic determinants. V. Biochemical and serological characteristics of naturally occurring, soluble antigen-binding T-lymphocyte-derived molecules.

Normal rat lymphocyte populations house a high percentage of lymphocytes with idiotypic, antigen-binding receptors for the major histocompatibility complex antigens of the rat. These receptors can be isolated from normal serum or lymphocyte supernatants. Idiotypic, antigen-binding molecules released from normal Lewis lymphocytes were thus isolated using anti-(Lewis anti-DA) immuno adsorbents. Analysis by SDS polyacrylamide electrophoresis using molecules labeled by external or internal means (125I or 3H) demonstrated that B lymphocytes produce molecules of 'conventional' 7S-8S IgM type. T-lymphocyte-derived molecules had a molecular weight of around 150,000 and consisted of two chains of similar size. Such single chains would succumb to proteolysis by normal serum factors to yield fragments in the size range of 30,000-40,000 daltons. All three groups of T-cell-derived molecules expressed both antigen-binding and idiotypic markers. No evidence was obtained that any light chains are linked to the T-receptor molecules. Serological analysis of the T-cell molecules failed to prove the existence of any determinants of constant immunoglobulin type, nor did these molecules express antigenic markers of major histocompatibility complex types.

Animals↗
PubMed1977

Automated fluoride ion determination. Determination of urine fluoride ion levels.

An automated method is described, using standard continuous flow techniques, for the determination of urine fluoride ion concentration using a fluoride ion selective electrode. It is shown that the kinetics of the electrode response to changes in fluoride ion can be used for the accurate measurement of fluoride ion concentration in urine, and that equilibration of the electrode response is not a prerequisite for the measurement of fluoride ion. Recovery experiments are in the range 83 to 90%; in-batch precision is between 0.9 and 1.6% and carryover 2.5% or less.

Autoanalysis↗
PubMed1977

Automated fluoride ion determination. Determination of serum fluoride ion levels.

A method is described, using standard continuous flow techniques, for the automated determination of serum fluoride ion concentration using a fluoride ion selective electrode. It is shown that the kinetics of the electrode response to changes in fluoride ion can be used for the accurate measurement of fluoride ion concentration in serum, and that equilibration of the electrode response is not a prerequisite for the measurement of fluoride ion. Recovery experiments are in the range 86.6-98.5%, in-batch precision is 1.0-6.1%, between-batch precision 5.5%, with carryover of -2.99%.

Autoanalysis↗
PubMed1976

The use of aldehyde dehydrogenase to determine H2O2 -producing reactions. I. The determination of the uric acid concentration.

The sequence of reactions catalyzed by uricase, catalase and aldehyde dehydrogenase for determination of the uric acid concentration was evaluated for human serum and urine samples. More than 60 substances were tested for possible interferences. Alcohol dehydrogenase, formaldehyde and homogentistic acid can disturb the proposed assay, but at concentrations which are not usually encountered in human serum or urine. In the presence of protein at least 99% of the uric acid was recovered.

Alcohol Oxidoreductases↗
PubMed1976

Determination of mycelial steroids with the aid of polyene antibiotics. II. Quantitative determination of the mycelial steroids of Mucor hiemalis.

UV absorption spectrum of polyene antibiotics was dramatically altered in the presence of steroids. The introduction of a steroid to an aqueous solution of polyene antibiotics resulted in a change in the ratio of absorbance of peak 3 (with shorter wavelength) to peak 1 (with longer wavelength), E3/E1. Interactions between 28 steroids and 4 polyene antibiotics were studied and the results revealed that the structures of steroids essential for the optimal interaction with polyene antibiotics were C-17 side chain, substitution C-3 hydroxyl group, intact steroid nucleus and aromatic A-ring. The ratio of E3/E1 was used for the determination of steroids in mycelium of Mucor hiemalis and the result was in good agreement with that obtained from gas chromatograph. The (-) strain had a greater change in the ratio of absorbance, E3/E1, than that of the (+) strain. The ratio of absorbance, E3/E1, decreased in the following order: the (-) strain, the (-) strain with the addition of the filtrate of (+) strains, the mated strains, the (+) with the addition of the filtrate of (-) strain and the (+) strain.

Amphotericin B↗