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Biomedical subjects

W Jonas

Publications and source records attributed to W Jonas.

36 records · Page 2Linked to original sources
PubMed1985

Variations in sheep serum conglutinating complement activity and pathway involved in reactivity with sheep erythrocytes sensitized by rabbit antibody.

Based on conglutination tests with the sheep E-rabbit A indicator system, three types of sheep sera were encountered. Type 1 sera failed to directly conglutinate or sensitize sheep E-rabbit A for conglutination by bovine conglutinin. Type 2 sera also failed to directly conglutinate sheep E-rabbit A but sensitized the indicator for conglutination by bovine conglutinin. Type 3 sera both directly conglutinated and sensitized sheep E-rabbit A for conglutination. Changes in serum type were induced in sheep by venepuncture (type 1 to type 2) or venepuncture and an intraperitoneal injection of yeast cells (type 2 to type 3). Direct conglutinating activity of type 3 sera was inhibited by heating serum at 50 degrees C for 30 min and was not restored by alternative activation pathway factor B. Chelation of Ca2+ in type 2 and 3 sera blocked sensitization of sheep E-rabbit A for conglutination by bovine conglutinin, indicating that the classical activation pathway was involved.

Acetylglucosamine↗
PubMed1985

Electrophoretic and serological analysis of mouse and rabbit antisera to zymosan or inulin treated with foetal lamb serum.

Most mouse antisera raised to zymosan treated with FLS containing Ca2+ and Mg2+ precipitated C3 and two other proteins from electrophoresed sheep serum. Rabbit antisera to zymosan-FLS precipitated C3 and three sheep serum proteins. All these antisera agglutinated sheep E-rabbit A complexes sensitized with sheep C at room temperature. Mouse antisera to zymosan treated with FLS containing Mg2+-EGTA and mouse antisera to inulin treated with FLS containing Ca2+ and Mg2+ or Mg2+-EGTA, precipitated only C3 from electrophoresed sheep serum, but did not agglutinate sheep E-rabbit A-sheep C. These results, together with antiglobulin studies indicate that zymosan, probably through a reaction with natural antibody in the FLS can activate sheep C by a mechanism that involves a Ca2+ and Mg2+-dependent pathway. In the presence of Mg2+-EGTA, zymosan and inulin activate sheep C via a Mg2+-dependent pathway. The results also show that antisera that will precipitate sheep C3 from electrophoresed sheep serum can be raised by immunizing mice and rabbits with inulin that has been treated with FLS or zymosan treated with FLS containing Mg2+-EGTA.

Animals↗
PubMed1984

Variations in sheep serum conglutinating and haemolytic activity for sheep erythrocytes sensitized by rabbit antibody.

Based on conglutinating and haemolytic reactions with sheep erythrocytes (E) sensitized by rabbit antibody (A), three types of sheep sera were encountered. Type 1 sera do not conglutinate or haemolyse sheep E-rabbit A. Type 2 sera failed to conglutinate or haemolytically active. Type 3 sera have both activities. Serum from one type 1 sheep still failed to conglutinate 5 days after venepuncture but was not haemolytically active (i.e., type 2). Some sheep that initially had type 2 sera had, five days after an intraperitoneal injection of yeast cells, sera with conglutinating activity (type 3 sera). Type 1, 2 and 3 sera all had haemolytic activity with human E-sheep A indicator cells. Pooled type 3 sera have the highest conglutinating titres with sheep E-rabbit A after 10 min incubation at 39 degrees C. At this stage, the haemolytic titres were very low. From 10 min, the conglutinating titres decreased whereas the haemolytic titres gradually increased until 80 min. Optimal conglutinating activity required less rabbit A to sensitize sheep E than did haemolytic activity.

Animals↗
PubMed1983

Inhibitory activity of heated ewe serum for ewe and ram serum complement.

In the presence of an indicator antigen-antibody complex, the complement (C) activity in ewe and ram serum was reduced or abolished by addition of ewe serum that had been heated at 56 degrees C for 10 minutes. Pre-incubation of heated ewe serum at 39 degrees C for 30 minutes with the C source prior to addition of the indicator system or addition at the same time caused similar reductions in C activity. Results from the haemolytic, conglutinating and haemagglutinating activities studied indicate that the ewe serum inhibitor(s) reacts with activated classical or alternative activating pathway components and/or the third component of C (C3). The presence of a potent C inhibitor(s) in ewe serum probably accounts for the low sheep C titres with some assay systems. As the heated ewe serum did not appear to activate ewe or ram C per se, it is more appropriate to regard it as 'inhibitory' rather than 'anticomplementary'.

Journal Article↗
PubMed1982

Conglutination and haemolysis of unsensitized human erythrocytes by bovine serum complement.

Unsensitized human erythrocytes (E) were haemolyzed by bovine serum to a titre of 1:16-1:32. In the single dilution beyond the haemolytic endpoint, the cells were conglutinated. In dilutions in which haemolysis occurred, cells were conglutinated before being lyzed. With no or minimal haemolysis, conglutination to 1:32-1:64 occurred in tests using insulin-absorbed serum, serum heated at 50 degrees C for 30 min and in tests incubated at 4 degrees C for 30 min. In two-stage tests, EDTA and Mg2+-EGTA prevented bovine C sensitization of human E for conglutination by bovine serum heated at 56 degrees C for 30 min. EDTA prevented haemolysis, but haemolysis to 1:16-1:32 occurred with serum dilutions containing Mg2+-EGTA. Haemolytic activity was restored to serum heated at 50 degrees C by a factor B-containing fraction. Conglutination and haemolysis were blocked by heating serum at 56 degrees C for 30 min and were reduced to low titres by absorbing serum with zymosan. These results strongly suggest that the conglutination reaction involved the classical activation pathway whereas the haemolytic reaction involved the alternative activation pathway. Thus, with dilutions of untreated or treated bovine serum, two C-dependent reactions and the pathways involved can be demonstrated by using unsensitized human E as an indicator system.

Agglutination↗
PubMed1982

Stimulation of the titre of a sheep serum factor that is related to the sheep complement system.

Serum from most sheep subjected to a single jugular bleeding, repeated bleeding or an intraperitoneal injection of yeast and repeated bleeding, showed an increase in the titre of a serum component called serum factor. Serum factor reached a peak titre 2 to 5 days after treatment started. For some sheep, the titre was elevated for a 9- to 12-day period whereas for others the titre dropped markedly on day 7 followed by a rise on day 9. Serum factor reacts with sheep erythrocytes sensitised with rabbit antibody (sheep E-rabbit A). Serum factor can be detected on sheep E-rabbit A using guinea-pig antiserum that reacts with sheep complement (C). Serum factor is inactivated by heating at 56 degrees C for 30 minutes, but is only partially inactivated at 50 degrees C for 30 minutes. The reaction of serum factor with sheep E-rabbit A is inhibited by chelators of Ca++ and/or Mg++. Serum factor appears to be related to the sheep C system. Preliminary results suggest it may he a component of the classical pathway of sheep C, possibly the second component, C2.

Journal Article↗
PubMed1981

Haemolysis of human erythrocytes heavily sensitized with sheep amboceptor by sheep complement chelated with EGTA or Mg2+-EGTA.

Human erythrocytes sensitized with an agglutinating dose of either sheep anti-human erythrocyte antiserum, IgM, slow or fast gamma-globulin antibody are haemolysed by foetal lamb or sheep serum complement (C) in the presence of ethyleneglycoltetraacetic acid (EGTA) or Mg2+-EGTA but not ethylenediaminetetraacetic acid (EDTA) or triethylenetetraminehexaacetic acid (TTHA). Dialysis of the C source against phosphate buffered saline rendered it inactive, but addition of Mg2+ or Mg2+-EGTA restored haemolytic activity. Haemolysis of sensitized erythrocytes took place more rapidly in buffer containing Ca2+ and Mg2+ than in EGTA or Mg2+-EGTA. Heating the C source at 50 degrees C for 30 min or 56 degree C for 3 min abolished haemolytic activity. In the presence of EGTA or Mg2+-EGTA, haemolytic activity was restored to 50 degrees C-heated serum by a CM-cellulose fraction that contained sheep factor B. These results show that sheep C, in the presence of EGTA or Mg2+-EGTA will haemolyse human erythrocytes heavily sensitized with sheep amboceptor. The alternative pathway of sheep C is thought to be involved.

Animals↗
PubMed1981

Alternative pathway activation of complement in fetal lamb serum by Trichostrongylus vitrinus larvae.

Fetal lamb serum (FLS) complement activated by incubation with Trichostrongylus vitrinus larvae was deposited on the larval surface and its presence was demonstrated by leucocyte and erythrocyte adherence reactions and by analysis of antisera from guinea-pig immunized with the larvae. The complement activation proceeded in the apparent absence of antibody and in the presence of ethylene glycol tetracetic acid (EGTA) or Mg++-EGTA but not ethylenediamine tetracetic acid (EDTA). FLS heated to 50 degrees C for 30 min was inactive, but activity was restored by addition of FLS factor B alone or factor B plus Mg++-EGTA. FLS treated with zymosan or inulin was inactive. These results suggest that this non-immune activation of sheep complement by T. vitrinus takes place via the alternative pathway.

Animals↗
PubMed1980

[Reduction in cardiotoxicity of ionic contrast media used in coronary angiography by added calcium--Clinical study (author's transl)].

In 16 patients with CAD, hemodynamic and electrophysiologic side effects were examined following selective coronary artery injections with Urografin 76%, a commonly used ionic contrast medium. A Millar transducer tipped catheter was placed in the left ventricle for continuous pressure recording also during injections. The unmodified contrast medium decreases peak left ventricular pressure (-22 +/- 8%) and dp/dt max (-27 +/- 13%) markedly at injection. With added calcium (22.5 mEq/l) this cardiodepressive reaction becomes diminished to -15 +/- 7% and -13 +/- 8% respectively with high significance (p < 0.001). This positive effect is even more marked using higher volumes of contrast material for injection. In contrast to animal experiments, calcium did not completely compensate the negative inotropic reaction even in higher concentration (33.75 mEq/l). The marked sinus slowing (-29 +/- 14%)--observed in patients and not influenced by the calcium addition--has an additional effect in the sense of a "negative frequency-inotropism" and is responsible for the residual cardiodepressive reaction. An influence on electrophysiologic side reactions can also be observed with added calcium but only in injections with higher volumes of contrast medium. QT-elongation, T-wave changes are reduced significantly. We did not see any unfavorable reactions caused by added calcium. The cardiodepressive side effects on the contractile force by commonly used ionic contrast media can be reduced by adding calcium in the above-mentioned concentration. This may be helpful when studying high risk patients and using high injection volumes.

Adult↗
PubMed1976

A twin study of human red blood cell catechol-o-methyl transferase.

Significant sibling-sibling and within-family correlations of human red blood cell catechol-o-methyl transferase activity have suggested a high degree of genetic control over levels of activity of this catecholamine-related enzyme. However, family studies do not disentangle genetic from environmental similarities as causative of within-family correlations. We therefore undertook a human twin study using the monozygotic-dizygotic comparison method. Twelve pairs of monozygotic twins had an intraclass correlation of 90 in red blood cell catechol-o-methyl transferase activity, and seven pairs of dizygotic twins had an intraclass correlations of 37. Heritability of the enzyme activity was estimated by different methods as between 68-100 per cent.

Adolescent↗