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Biomedical subjects

K Otto

Publications and source records attributed to K Otto.

At least 55 records · Page 3Linked to original sources
PubMed1986

Improved purification and some properties of bovine lysosomal carboxypeptidase B.

Lysosomal carboxypeptidase B (peptidyl-L-amino-acid hydrolase, EC 3.4.18.1) from bovine spleen purified to apparent homogeneity was found to have a molecular weight of 52 000 in the absence and of 25 000 in the presence of urea, determined by gel filtration, indicating the existence of two subunits of identical size. The amount of approx. 15% carbohydrate estimated after cleavage by endoglycosidase H was shown to be insignificant for enzymatic activity. The isoelectric focusing separated lysosomal carboxypeptidase B into several protein bands - each enzymatically active - with a range of isoelectric points between 4.6 and 5.2. The titration of the sulphydryl group in the active site of the enzyme with the proteinase inhibitor E-64 yielded one thiol group per molecule. A maximum of activation was achieved by the addition of selenocystamine together with dithioerythritol and EDTA in the incubation solution. Under these conditions the carboxypeptidase hydrolyzed benzoylglycylarginine (80 kat/mol enzyme), benzoylarginine amide (38 kat/mol enzyme) and carbobenzoxyglutaryltyrosine (110 kat/mol enzyme). Slight enzymatic activities towards benzoylarginine 2-naphthylamide and benzoylarginine p-nitroanilide could be measured. With the oxidized insulin B chain, lysosomal carboxypeptidase B exhibited only carboxypeptidase activity.

Animals↗
PubMed1983

Sequence of the lacZ gene of Escherichia coli.

The nucleotide sequence of the lacZ gene coding for beta-galactosidase (EC 3.2.1.23) in Escherichia coli has been determined. Beta-Galactosidase is predicted to consist of 1023 residues, resulting in a protein with a mol. wt. of 116 353 per subunit. The protein sequence originally determined by Fowler and Zabin was shown to be essentially correct and in an Appendix these authors comment on the discrepancies.

Bacterial Proteins↗
PubMed1983

Comparison of Papanicolaou staining and Feulgen staining for automated prescreening.

Feulgen staining is considered to be a quantitative DNA-specific cytochemical procedure. The applicability of this staining in high-resolution cytometry was tested in comparison with a regressive Papanicolaou staining. Papanicolaou-stained or Feulgen-stained intermediate and carcinoma cells selected by a cytologist were examined with a Zeiss scanning microscope photometer at 546 and 560 nm, respectively. After cell image segmentation and feature extraction, a statistical data evaluation was carried out by computer. Cell distributions with respect to four selected nuclear features demonstrated the influence of the staining procedure on cell feature measurements. The discriminatory power of the classification system as related to both staining procedures was studied using discriminant analysis. Using only nuclear features, a 7.3% improvement of the overall correct classification rate (from 85.0% to 92.3%) was achieved using Feulgen staining. The misclassification rate was simultaneously reduced by 50%. Using cytoplasmic as well as nuclear features, a 98% rate of correct classification was achieved.

Cell Nucleus↗
PubMed1981

pUR222, a vector for cloning and rapid chemical sequencing of DNA.

A multipurpose plasmid, pUR222, was constructed. It contains six unique cloning sites (PstI, SalI, AccI, HindII, BamHI and EcoRI) in a small region of its lac Z-gene part. Insertion of foreign DNA into the plasmid can be easily detected. Bacteria harbouring recombinant plasmids generally give rise to white colonies, while those containing only vector DNA form blue colonies on indicator plates. Plasmid DNA purified by a rapid method (Birnboim, H.C. and Doly, J. (1979) Nucl. Acids. Res. 7, 1513-1523) can be used for chemical sequencing of the cloned insert DNA. Labeled fragments need not be isolated after cutting with the proper restriction enzymes and are treated directly according to the sequencing protocol of Maxam and Gilbert.

Base Sequence↗
PubMed1981

Numerical analysis of cell populations in smear and monolayer preparations from the uterine cervix. I. The proportions of isolated, abnormal epithelial cells in slides from one applicator.

Automated screening systems with a receiver operating characteristic (R.O.C.) demand a minimum number of isolated and diagnostically relevant cells to classify cytologic specimens. Since routine Papanicolaou smears have not proven suitable for this, a new preparation procedure based on sedimentation velocity separation has been developed. A population analysis was made to assess the diagnostic relevance of the new procedure. For each of 21 histologically confirmed cases, three types of slides were made from material obtained by a single cotton-tipped applicator: (1) a routine smear and slides prepared from the (2) supernatant fraction and (3) sedimented fraction of the remaining material after suspension and separation. Results showed that only one-third of the squamous epithelial cells obtained in each case were found on the routine smear. Of those, only 39% were isolated cells, as compared with 81% of the cells in the residual (suspended) material. Further, in cases of slight and moderate dysplasia as well as carcinoma in situ, an enrichment of the number of pathologic cells was noted when comparing the sedimented fractions to the original suspensions. This would seem to prove the utility of the new preparation procedure as the basis for automated analysis based on samples instead of on single cells.

Autoanalysis↗
PubMed1980

The action of bovine spleen cathepsins B and D on the cytoplasmic ribonuclease inhibitor from rat liver.

The inactivation by the lysosomal cathepsins B or D of the cytoplasmic neutral ribonuclease inhibitor has been investigated with respect to the required amounts of cathepsin, optimal pH and time course. With a pH optimum between 5 and 5.5, a possible role of these endopeptidases in regulating the inhibitor and, concomitantly, the ribonuclease and RNA concentrations in the cell is discussed.

Animals↗
PubMed1979

Sedimentation velocity separation: a preparation method for cervical samples.

A preparation procedure, aiming at monolayer deposition of cervical exfoliative material on glass slides for high resolution prescreening has been developed. The main features of this procedure are centrifugal deposition after suspension and sedimentation of samples over isopycnic medium of 1.026 density. Fractioning of the separation column after centrifugation at 50 X g yields two preparations with leukocytes, bacteria and cellular debris predominantly located on the first slide and epithelial cells on the second one. The degree of spatial cellular isolation as well as the amount of diagnostically relevant cells per slide seem to fit the requirements of automated high resolution analysis.

Cell Separation↗
PubMed1979

Cytomorphologic results of preparation experiments for monolayer deposition of cervical material.

For automated prescreening methods by high resolution analysis serving as a detecting method in gynecologic mass screening programs a new monolayer deposition method of cervical material has been used. This method will be outlines briefly and the mode of evaluation as well as current cytomorphological findings will be presented. With regard to measurability of the slides prepared according to the new method a number of cytologic criteria were thought to be of particular importance. These criteria are delineated and compiled in a table. A form in which these criteria were listed was filled in by cytopathologists for each slide evaluated. When performing isolation and centrifugation procedures several new morphologic questions arose to the cytopathologist which can only partly be answered by now. If taking into account all criteria of evaluation it may be followed from the present experiences that slides of cervical material are much more suited for automated prescreening methods by high resolution analysis if prepared after isolation and centrifugation in macromolecular liquids than are conventional Papanicolaou smears or slides from suspensions with isolated cells that were not subjected to centrifugation procedures.

Cell Separation↗
PubMed1979

[Suicide attempts with drugs].

A sample of 352 subjects, who had made a suicide attempt by ingesting pills examined in the aspects of age and sex, number and origin of used tablets and combination of pill ingestion with alcohol or other methods. Younger people under 20, took nearly exclusively tablets, which they accidentally found at home. Elder patients over 50, used nearly exclusively prescribed drugs. The typical patients attitudes to this suicidal method gives us the right to speak about such suicide attempts as "attempts by tablets". The pharmacological substance is unimportant and plays a secondary role. The seriousness of suicide attempts depends on topical situation of person, biological and social factors; it does'nt dependent on number or pharmacological substance of tablets.

Adult↗
PubMed1978

[Primary sarcomas of the gastrointestinal tract (author's transl)].

From 1952 to 1976 2203 malignant tumours of the gastrointestinal tract were seen at the Surgical Clinic of the M.H.L., 18 of them were sarcomas. There was a predominance of carcinomas of the stomach (Sa: Ca = 1:229) and of the colon (1:162), whereas sarcomas of the small intestine were found in a relation of 1:0,9. X-ray diagnosis of the gastric sarcomas is difficult, only those with endogastric growth can be recognized by gastroscopy. The postoperative prognosis of gastric sarcomas is better than that of gastric carcinomas. Sarcomas of the small intestine have a high mortality rate because of a high rate of ileus and perforation. Sarcomas of the colon - normally localized in the caecum or rectum - have a better prognosis, seldom stenosis can be seen.

Adult↗