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J Srajer

Publications and source records attributed to J Srajer.

At least 37 records · Page 2Linked to original sources

Inhibitory effect of tunicamycin on the adhesivity and aggregation of embryonic brain cells.

Tunicamycin (TM) - (0.1, 1.0 and 10 micrograms/ml) inhibits insignificantly the adhesivity of embryonic mice brain cells during the first 120 min of incubation. The effect is not dose dependent. The concentration of 10 micrograms/ml added at the onset of experiments has a drastic effect during the time period in which cell regeneration, cell movement and formation of aggregates occurs. Up to the 5th day in vitro (DIV), aggregation is completely inhibited and disrupted parts of cells are mostly present in the medium. The concentration of 1 microgram/ml is less effective, and 0.1 microgram/ml is practically without effect. EM analysis shows that tunicamycin (10 micrograms and 1 microgram/ml) diminish the regeneration and integrity of plasmatic membranes, 10 micrograms/ml of tunicamycin destroys cytoplasmatic organelles which is probably the cause of the decline of cellular regeneration and of aggregate formation. Tunicamycin (10 micrograms/ml), if added to the already formed aggregates evokes their disintegration and lower doses (1 microgram/ml) liberated cells from aggregates into the medium.

Animals↗

Adhesion of dissociated mouse embryonic brain cells. A new method of quantitative evaluation.

The adhesion of mouse embryonic brain cells was measured in a rotating chamber. A method is proposed for quantitative evaluation of adhesion kinetics. Dissociated cells were incubated in a planparallel chamber and pictures were taken between time 0-120 min. Film negatives were evaluated by computer--controlled scanning. Ten thousand individual data area obtained from one frame and 1,000 levels of absorbency are distinguished. A method is described which allows the discrimination of area, density and the shape of adhering cells. The influence of the dissociation procedure on cellular adhesion was studied. Short trypsinisation (0.025% trypsin for 5 min) followed by sieving was most favourable for adhesion. Mechanical sieving and dissociation with EGTA (Ca2+ chelator) gave less satisfactory results. Significantly diminished adhesion was observed after prolonged trypsinisation. If cells were incubated in media lacking Ca2+, adhesion was significantly inhibited. The kinetics of adhesion follows the curve of flocculation kinetics independently of the dissociation procedure and composition of the medium.

Animals↗

Human serum Zn-alpha2-glycoprotein in amniotic fluid.

Human serum Zn-alpha2-glycoprotein (Zn-alpha2-GP) was found to be present in the amniotic fluid in the mean concentration of 0.98 +/- 0.40 mg/100 ml, which represents about one-tenth of its concentration in the maternal serum (9.65 +/- 1.18 mg/100 ml). Its concentration in the amniotic fluid was proportional to the amniotic fluid total protein and very approximately to the maternal serum Zn-alpha2-GP. The relationship between the maternal serum Zn-alpha2GP and the maternal serum total protein as well as between the amniotic fluid total protein and the maternal serum total protein was found to be not significant. The amniotic fluid Zn-alpha2-GP as well as the amniotic fluid total protein showed some increase during gestation to reach the highest values at the end of the second trimester. At present both the origin and significance of the amniotic fluid Zn-alpha2-GP are not known.

Amniotic Fluid↗

Herpesvirus group antibodies in children with Hodgkin's disease.

During the period of three years ((1972-1974), serum samples from 60 patients (children and adolescents) with lympho-hematopoietic system diseases were examined for antibodies to all four human herpesviruses. Among these were 26 active Hodgkin's disease (AHD) patients and 6 HD patients with a minimum five years' remission. Simultaneously matched controls (age, sex) of AHD patients were examined. Antibody levels against the viral capsid antigen of Epstein-Barr virus (EBV/VCA) in AHD patients were significantly higher, with overrepresentation of higher titres (greater than or equal to 1:160), than in matched controls. The lowest EBV/VCA antibody titres were in the leukemia-non-Hodgkin's lymphoma patients. We could not prove any significant relationship between cytomegalovirus or herpes simplex virus type 1 antibody titres and AHD or any other disease of lympho-hematopoietic system. The varicella-zoster virus antibody titres in AHD patients were significantly higher than in matched controls. No significant differences in antibodies against EBV/VCA and the other human herpes viruses between the evolution and remission period of AHD patients could be detected. No differences in EBV/VCA antibody titres were observed between the healthy school-children aged 10 to 15 years who were and who were not in contact with a HD patient.

Adolescent↗