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Biomedical subjects

J Frey

Publications and source records attributed to J Frey.

At least 271 records · Page 15Linked to original sources
PubMed1981

Specific-purpose plasmid cloning vectors. II. Broad host range, high copy number, RSF1010-derived vectors, and a host-vector system for gene cloning in Pseudomonas.

Host-vector systems have been developed for gene cloning in the metabolically versatile bacterial genus Pseudomonas. They comprise restriction-negative host strains of Pseudomonas aeruginosa and P. putida and new cloning vectors derived from the high-copy-number, broad-host-range plasmid RSF1010, which are stably maintained in a wide range of Gram-negative bacteria. These plasmids contain EcoRI, SstI, HindIII, XmaI, XhoI, SalI, BamHI, and ClaI insertion sites. All cloning sites, except for BamHI and ClaI, are located within antibiotic-resistance genes' insertional inactivation of these genes during hybrid plasmid formation provides a readily scored phenotypic change for the rapid identification of bacterial clones carrying such hybrids. One of the new vector plasmids is a cosmid that may be used for the selective cloning of large DNA fragments by in vitro lambda packaging. An analogous series of vectors that are defective in their plasmid-mobilization function, and that exhibit a degree of biological containment comparable to that of current Escherichia coli vector plasmids, are also described.

Bacteriophage lambda↗
PubMed1981

[Rigid internal fixation of symphysiolysis (author's transl)].

Report is given here on the successful treatment of 7 cases with symphysiolysis. The advantages of early plate fixation are emphasized as it provides anatomic reconstruction of the pelvis and reduces hospitalization. The question is raised wether this procedure should be applied if genito-urinary tract lesions are associated too.

Adult↗
PubMed1980

[Under-hydroxylation of collagen synthesized by cultured fibroblasts].

The collagen secreted by dermal fibroblast cell cultures, previously labelled with 3H-proline, was extracted and purified by carboxymethyl cellulose. The ratio of hydroxyproline to proline showed that the collagen produced by cell cultures may be under-hydroxylated in comparison to the ratio observed in the types of collagen extracted from human skin. Then, it is concluded that it is not sufficient to determine only the hydroxyproline content for a collagen biosynthesis study in cell cultures. This low hydroxyproline content may explain the rapid catabolism of a part os newly synthetized collagen in vitro.

Cells, Cultured↗
PubMed1980

Employment of gas-liquid chromatography for the analysis of collagen amino acids in biopsy tissue.

In this paper, gas-liquid chromatography, adapted for the determination of collagen amino acids, is described. This technique was attractive for its sensitivity in that only a small amount of protein such as in 0.5 mg of tissue, especially as obtained from biopsy tissue, was needed for the separation and determination of proline (Pro), 4-hydroxyproline (4-Hyp), 3-hydroxyproline (3-Hyp), lysine (Lys), hydroxylysine (Hyl) and epsilon-hydroxy-norleucine (epsilon-PH-Norleu), the characteristic amino acids of collagen. Thus, without purification of collagen, by determining the ratio Hyl/4-Hyp and 4-Hyp/Pro it was possible to determine some anomalies in the collagen content of biopsy tissue (skin or liver). The ratio Hyl/4-Hyp allows an estimation of the lack of hydroxylation of polypeptidic lysine as in the Ehlers-Danlos syndrome type VI; and the ratio 4-Hyp/Pro allows measurement of variations in collagen content in relation to protein, especially in the liver, as in alcoholic cirrhosis.

Adult↗
PubMed1980

Demyelinating radiculopathy in the Kearns-Sayre syndrome: a clinicopathological study.

In the few previously autopsied patients with the Kearns-Sayre form of progressive ophthalmoplegia, the most prominent abnormalities have been in muscle, with less conspicuous changes in the central nervous system, primarily in the brainstem. Similar findings were present in the case reported here, but in addition there was severe demyelination in the initial few millimeters of the cranial and spinal motor roots distal to the glial-Schwann cell junction. Milder demyelination was observed in the dorsal spinal and afferent cranial nerve roots, including the eighth nerve, but deafness was due to virtually total destruction of the organ of Corti. Our observations suggest that a radiculopathy may be a feature in some cases of Kearns-Sayre syndrome.

Adult↗
PubMed1980

[Simultaneous characterizations of 3-prolylhydroxylase and 4-prolylhydroxylase activities by ion exchange chromatography].

3-prolyl hydroxylase activity measurements have already been described by Kivirikko and al, using specific methods. The aim of the present work was to show that the specific and rapid method used for 4-prolyl hydroxylase activity measurement, involving protocollagen [3H-4] proline (measuring of tritiated water enzymatically obtained), could be used for 3-prolyl hydroxylase activity estimation on the same sample: tritiated water enzymatically produced by 4-prolyl hydroxylase was collected by distillation, and the amino acids enzymatically modified were analysed after HCl 6 N hydrolysis of dried incubation medium, by cation exchange chromatography. The characterization of enzymatically obtained 3-hydroxyproline was performed using three means. The elution peaks reported were in the same position as the elution peak of pure 3-hydroxyproline and 4-hydroxyproline. Moreover, tritiated 3-hydroxyproline and 4-hydroxyproline were obtained only after incubation of labelled substrate with crude preparation of prolyl hydroxylases from chick embryos. Some possible artefacts such as dicetopiperazines and pyrrol-2-carboxylic acid have been shown to be distinguished chromatographically from 3-hydroxyproline and 4-hydroxyproline. The high ratio of measured (Formula: see text) activities, near 5.5 p. cent, is discussed.

Chromatography, Ion Exchange↗
PubMed1980

[Cytopharmacology in fibroblast culture].

Fibroblast cultures represent a particularly valuable model for the study of toxic or pharmacological effects upon collagen metabolism, the clinical expression of disturbances of which, corresponds to the process of fibrosis. The suggested method consists of the following: estimation of toxic concentrations by observation of the inhibition of cell growth and modifications of ultrastructure; a metabolic study corresponding to the measurement of biosynthesis and of the secretion of collagen and non-collagen proteins and determination of the type of collagen synthesized. The model was evaluated experimentally with tobacco smoke extracts and D-penicillamine.

Cells, Cultured↗
PubMed1980

Relationship between hemoglobin A1c and insulin C-peptide in anomalies of carbohydrate metabolism.

In this paper, we have compared the results obtained for hemoglobin A1c and C-peptide concentrations, was not convenient for the diagnosis of anomalies in the regulation of carbohydrate metabolism in obesity or in latent diabetes. Nevertheless, hemoglobin A1c allowed us to check carbohydrate metabolism and to discriminate diabetes treated by oral therapy from insulin dependent diabetes; in these latter cases, hemoglobin A1c concentration varied inversely as C-peptide concentration as it was shown by the method of factor analysis in particular "principal components analysis". In the control of insulin dependent diabetes in a remission, hemoglobin A1c allowed assessment of the regulation of carbohydrate metabolism after suppression of insulin therapy. Thus, hemoglobin A1c is an index of the adaptation of insulin secretion in anomalies of carbohydrate metabolism.

C-Peptide↗
PubMed1980

Case oriented group discussions for family physicians.

Curriculum in family medicine and primary care includes various areas of concern for educators in the behavioral sciences. Most of this concerns the physician-patient relationship as the focus for teaching and learning. This paper outlines the work of a longitudinal, case oriented group of family physicians as it reflects the correlation between the actualities of practice and the curriculum in behavioral science for family practice residents. Also discussed is the issue of potential "typologies" as elaborated in the family physicians' reasons for case presentations. Such groups assist faculty and practitioners in their own awareness of educational and patient care issues in the physician-patient relationship as well as serve as a foundation for building a relevant behavioral science curriculum for residents and students.

Behavioral Sciences↗
PubMed1979

Identification of a collagen-like antigen different from C1Q component of complement in serum.

The problem of the proportions of hydroxyproline proteins in serum linked to collagen and to the C1Q component of complement was examined. The C1Q component from human and bovine serum, and acid soluble calf skin collagen were purified. Antibodies to soluble collagen were prepared. With these antibodies we found by immunoelectrophoresis that in serum two distinct antigens exist: one reacts with antiserum to C1Q and the other reacts with antiserum to collagen. The collagen-like antigen may be precipitated by sodium chloride 4.3 mol/1.

Animals↗
PubMed1979

[Determination of free intracellular proline pool in fibroblast cultures].

By using a direct, rapid, sensitive colorimetric method, free intracellular proline pool from human adult skin fibroblasts in monolayer was determined. Thus under identical experimental conditions, free intracellular proline pool was about 20 pmol proline/micrograms cellular proteins, whatever the cell lines from human adult skin fibroblasts, the passage and the time of subculture. Besides, there was a poor correlation between collagen biosynthesis in fibroblast cultures and free intracellular proline pool.

Adult↗
PubMed1979

The effects of an Escherichia coli dnaAts mutation on the replication of the plasmids colE1 pSC101, R100.1 and RTF-TC.

The rate of replication of the plasmids colE1, pSC101, R100.1 and pAR132 (an RTF-TC derivative of the drug resistance factor R100.1) has been investigated directly by DNA:DNA hybridization. These rates have been compared, in a dnaAts strain, to that of various markers of the host chromosome at permissive and non-permissive temperatures. Chromosome initiation in the dnaAts strain stops rapidly after a shift to the non-permissive temperature, but plasmids R100.1 and pAR132 do not seem to be affected directly and continue replication for some time. The colE1 replication rate undergoes a large increase after the temperature shift, followed by a rapid decrease to a very low level 25 min after the shift. In contrast pSC101 replication stops immediately after the shift. ColE1 is able to replicate in an integratively suppressed dnaAts strain at 42 degrees C whereas pSC101 stops replication immediately under these conditions. We conclude that R100.1 and its derivative RTF-TC can replicate without a functional dnaA product; that colE1, while affected by a shift in temperature in a dnaAts strain, does not directly require dnaA; and that the plasmid pSC101 has an absolute requirement for dnaA. The absolute requirement of pSC101 for dnaA in the integratively suppressed Hfr strain provides a useful system for further investigation of the dnaA function.

DNA Replication↗
PubMed1979

External and internal forms of yeast aminopeptidase II.

1. Intact cells of Saccharomyces cerevisiae catalyze the hydrolysis of various aminopeptidase substrates. This activity is not due to permeation of substrates and products but exerted by an external enzyme. 2. From its substrate specificity and the effects of pH and inhibitors the enzyme was identified as aminopeptidase II. 3. About 40% of total aminopeptidase II activity is detectable with untreated exponentially growing cells. Up to two thirds of the external enzyme is released into the medium during enzymic digestion of the cell wall, while little enzyme is liberated by osmotic shock. Membrane preparations contained only small amounts of aminopeptidase II; thus, the localization of the external enzyme appears to be similar to that of the so-called 'periplasmic' yeast hydrolases. 4. By cytochemical methods the presence of aminopeptidase II in the cell envelope was visualized. 5. In contrast to aminopeptidase II, yeast dipeptidase is an entirely intracellular enzyme.

Aminopeptidases↗