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Biomedical subjects

M Jörg

Publications and source records attributed to M Jörg.

8 recordsLinked to original sources
PubMed2000

Gene sam1 encoding adenosylmethionine synthetase: effects of its expression in the fission yeast Schizosaccharomyces pombe.

By screening gene libraries of Schizosaccharomyces pombe with a DNA fragment encoding part of the Saccharomyces cerevisiae S-adenosylmethionine synthetase (SAMS), we isolated the fission yeast sam1 gene. Its sequence exhibits good homology to SAMSs of other organisms and reveals the motifs characteristic for SAMSs. SAMS activity and sam1 mRNA levels decrease when cells enter stationary phase. In haploid strains, gene sam1 is essential for growth; if weakly expressed, cells mate and sporulate at a reduced rate. Strains overexpressing sam1 exhibit methionine-sensitive growth. This methionine-induced growth inhibition is partially relieved by adenine. We assume that methionine reduces the level of one or several adenine nucleotides by a SAMS-mediated mechanism. Intracellular SAM levels increase drastically by exogenously added methionine. This increase predicts that mutants exhibiting methionine revertible phenotypes can be indicative for mutations in proteins exhibiting SAM-dependent functions. In agreement with this prediction, we show that mutant pmt2-5 has this phenotype and that gene pmt2 encodes a potential SAM-dependent enzyme.

Amino Acid Sequence↗
PubMed1994

[Category system for microanalysis of early mother-child interaction].

As part of a prospective longitudinal study on the pathogenesis of neuropsychiatric disorders in children at biological and psychosocial risk, a system of categories was developed for the assessment of early mother-child interaction. A computer program for recording observational data in synchrony with video images by online coding was developed for this purpose. It permits second-by-second recording of basic categories and complex interactional behavior of mother and child. An evaluation of instrumental validity, interrater reliability and the validity of the system with 48 mother-child dyads yielded positive results. Measures of interaction (synchrony, reciprocity, elicit) and of disturbed interactions were defined.

Child↗
PubMed1993

[Importance and determinants of early mother-child relations].

In a prospective longitudinal study on child development from birth to age eight 362 first-born infants and their families were investigated. The subjects were distributed across the nine cells of a two-factorial design, factor 1 representing the degree of organic, factor 2 the degree of psychosocial risk. At age 3 months mother-child interaction was videotaped and evaluated with microanalytic technique. The quality of MCI could be demonstrated to be as predictive for later cognitive development as early developmental tests. Social-emotional problems of the toddler and preschool child was predicted better by parameters of early MCI than by temperament. Disturbed interactions were associated with later cognitive retardation and enhanced behavior problems. MCI is significantly determined by neglect and rejection, which showed typical behavioral patterns. The early separation of mother and high risk newborn itself did not lead to alterations in maternal attachment. Compared with mother daughter dyads early interaction of mother and son was characterized by more reactivity and positive emotion.

Affect↗
PubMed1992

A decrease in plasminogen activator inhibitor-1 activity after successful percutaneous transluminal coronary angioplasty is associated with a significantly reduced risk for coronary restenosis.

To determine a possible relation of changes in plasma levels of plasminogen activator inhibitor 1 (PAI-1) and tissue plasminogen activator (t-PA) to the development of coronary restenosis after successful coronary angioplasty (PTCA), we followed 104 patients with a low grade residual stenosis after PTCA (less than 30%) for a period of 12 months. PAI-1 plasma levels (functional activity) and t-PA antigen were determined 1 day before PTCA and 3 days, 3 months and 6 months thereafter. Thirty-four patients (32.69%) developed angiographically proven coronary restenosis (group A) within a time range of 4-48 weeks (median 12.5 weeks) after PTCA while the remaining patients (group B) had neither clinical signs nor angiographic evidence of restenosis after 6 months. No significant differences could be demonstrated in t-PA antigen or PAI-1 activity (plasma levels between the two groups of patients the day before PTCA). During the whole observation period t-PA plasma levels were not significantly different between the two groups; however, PAI-1 plasma levels were significantly higher at 3 months and 6 months after PTCA in patients of group A (p less than 0.005). When the pattern of PAI-1 plasma levels over time (increase or decrease between two consecutive time points of blood collection) was used to discriminate between the two study groups only 3.5-18% of patients with a decrease in PAI-1 developed coronary restenosis within the following observation period in contrast to 25-58% of patients with an increase in PAI-1 plasma levels (p less than 0.05 to p less than 0.0005).

Aged↗
PubMed1985

Kinetic analysis of plasminogen activation by purified plasma kallikrein.

Kinetics of plasminogen activation by purified activated plasma kallikrein have been studied in a purified system using Glu-plasminogen as a substrate. A synthetic paranitroanilide substrate was used for quantification of the formed plasmin. In that system kallikrein cleaved plasminogen with a Km value of 0.56 microM, a kcat of 1.6 X 10(-4) s-1 and a catalytic efficiency kcat/Km of 2.7 X 10(-4) s-1 microM-1. Addition of CNBr fibrinogen fragments resulted in an increase of Km to 1.18 microM, an increase of kcat to 5.1 X 10(-4) s-1 and an increase in the catalytic rate constant kcat/Km to 4.3 X 10(-4) s-1 microM-1. Addition of purified high molecular weight kininogen had no effect on the kinetics of plasminogen activation whether or not stimulating fibrinogen fragments were present. A stimulating effect of fibrinogen fragments could also be shown for the cleavage of the low molecular weight paranitroanilide substrate H-D-Pro-Phe-Arg-pNA by kallikrein; in that system the kcat for substrate cleavage by kallikrein increased from 200 s-1 to 280 s-1, while the Km value remained unchanged. From these data it can be concluded that based on enzyme kinetic studies plasminogen activator activity of purified plasma kallikrein is about 1/1000 of that of high molecular weight urokinase and is only slightly influenced by addition of stimulating fibrinogen fragments. Addition of high molecular weight kininogen does not affect plasminogen activator activity of purified plasma kallikrein.

Fibrin↗
PubMed1979

[Isolation of immune complexes from the vascular wall in experimental immunovasculitis].

In experimental immunvasculitis immunocomplexes of the vessel wall have been detected by indirect immunofluorescence method. In the aortic intima linear deposition, in the small arteries and arterioles segmental fluorescence was observed in all layers of the vessel wall. In some regions a marked positive perivascular reaction was also revealed. Immuncomplexes of the vessel wall may play a part in the preservation and prolongation of the alterations of the vessel wall.

Animals↗