Internalization of triiodothyronine-bovine serum albumin-colloidal gold complexes in human peripheral leukocytes

Complexes of triiodothyronine-bovine serum albumin-colloidal gold were specifically internalized in human peripheral leukocytes after 5 min of incubation. The specificity was partially lost after a longer incubation.     

Effect of ionic environment on densities of membrane-associated particles in presynaptic membranes observed in freeze-fractured synaptosomes.

The effects of high-K and high-Ca in the incubation medium on membrane-associated particles of the presynaptic membranes were examined. There was a marked increase in the density of protoplasmic fracture face after incubation in the high-K or high-Ca medium.     

Effect of ionic environment on densities of membrane-associated particles in presynaptic membranes observed in freeze-fractured synaptosomes

Summary The effects of high-K and high-Ca in the incubation medium on membrane-associated particles of the presynaptic membranes were examined. There was a marked increase in the density of protoplasmic fracture face after incubation in the high-K or high-Ca medium.     

A study of irrigation fluids for neurosurgery on brain primary cell cultures

Summary Primary cell cultures from newborn rat brain hemispheres were exposed to different irrigation fluids used in neurosurgery. The cells died after incubation for 5 min with hydrogen peroxide, and the number of cells was drastically decreased after 10 sec of incubation. They shrank after incubation in Elliott's artificial cerebrospinal fluid for 3 h, but the viability as determined by trypan blue exclusion test was not affected. Physiological sodium chloride, Ringer's solution and the culture medium 199 with Hank's salt had no noticeable effect on the viability or morphology of the cells.Acknowledgments. This study was supported by grants from the Medical Faculty of Göteborg and from Statens Naturvetenskapliga Forskningsråd. We want to thank Dr Åke Sellström and Dr Hans-Arne Hansson for valuable discussions.     

Estimation of the methylating capacity of the pineal gland. With special reference to indole metabolism

In order to obtain more information on the methylating capacity of the pineal gland, a method determining the formation of different 5-methoxyindoles in the pineal gland was developed. The method depends on measuring the incorporation of labelled methyl groups into the various hydroxyindoles present in the pineal gland, after incorporation of pineal tissue with labelled S-adenosyl methionine. Hydroxyindoles were not added to the incubation medium. After incubation thin-layer chromatography was performed with pineal tissue together with the incubation medium; the spots were scraped and counted.     

Regulation of isolated rat hepatocyte volume in hypoosmotic media]

Isolated hepatocytes behave like osmometers immediately after an incubation in hypo-osmotic media. During long-term incubation periods they recover their normal volume either in the absence or in the presence of ouabain. The volume regulation is parlty due to a decrease in intracellular potassium and amino acid contents.     

Sexual differences in the development of plasma thyroxine levels in the embryo and young chick]

Plasma thyroxine (T4) levels were separately ascertained in male and female embryo and young chicken from the 12th day of incubation till the 4th day after hatching by the thyroxine binding globulin technique. In both sexes, plasma T4 reach a peak the 20th day of incubation, but values are significantly higher in females. A sharp decrease occurred thereafter, plasma T4 tending toward adult values the 4th day after hatching.     

Abnahme des Cytochroms P450 nach Inkubation mit CCl4 in einem NADPH-regenerierenden System und teilweise Umwandlung in Cytochrom P420

Summary Isolated damage of cytochrome P450 and partial conversion to cytochrome P420 appears after incubation of carbon tetrachloride with a NADPH-regenerating enzyme system and the microsomale fraction. This effect enlarges after phenobarbital pretreatment.     

Evidence for a novel racemization process of an asparaginyl residue in mouse lysozyme under physiological conditions

We examined chemical reactions in mouse lysozyme after incubation under physiological conditions (pH 7 and 37°C). After incubation for 8 weeks, racemization was observed specifically at Asn127 among the 19 Asp/Asn residues in mouse lysozyme. Furthermore, analysis of the primary structure showed that the racemized residue was not Asp, but Asn, which demonstrates that deamidation and isomerization did not occur. These results mean that this racemization occurs without forming a succinimide intermediate. This is the first example of D-asparaginyl formation in a protein occurring during the racemization process under physiological conditions.Received 16 September 2004; received after revision 26 October 2004; accepted 12 November 2004     

Estimation of the methylating capacity of the pineal gland. With special reference to indole metabolism

Summary In order to obtain more information on the methylating capacity of the pineal gland, a method determining the formation of different 5-methoxyindoles in the pineal gland was developed. The method depends on measuring the incorporation of labelled methyl groups into the various hydroxyindoles present in the pineal gland, after incorporation of pineal tissue with labelled S-adenosyl methionine. Hydroxyindoles were not added to the incubation medium. After incubation thin-layer chromatography was performed with pineal tissue together with the incubation medium; the spots were scraped and counted.The authors wish to express their gratitude to Prof. Dr. J.C. van de Kamer and Dr F.C.G. van de Veerdonk for their stimulating interest in these studies.     

Zur Gewinnung von Induktionsstoffen aus Hühnerembryonen

Summary From chick embryos, fractions were prepared which, after implantation into new gastrulae, preponderantly give deuterencephalic or spinocaudal inductions. The behaviour of these fractions after incubation with thioglycolic acid or hydrolysis with trypsin is described.      

Formation of cutaneous nerve trunks in the chick. Ultrastructural and quantitative analysis]

In chick skin structuration of nervous trunks takes place at 14-15 days of incubation, at the time of formation of the adult pattern of cutaneous innervation. At this same stage, myelogenesis begins, but develops mainly after hatching: only 4% of axons are myelinated at hatching, 40% in 6-week old Chickens and 60% in adults. This "critical" stage (14-15 days of incubation) apparently corresponds to the stabilization of cutaneous nerve supply.     

Comparative studies on the covalent binding of the carcinogen benzo(a)pyrene to DNA in various model systems.

The covalent binding of tritiated benzo(a)pyrene (BP) to DNA has been determined in rat liver in vivo, in rat liver perfused in situ, after incubation of BP with liver single cells, with liver homogenate, with liver microsomes and DNA, with fibroblasts from a rat granuloma pouch, and with 2 cell lines. Liver single cells were found to be a valuable compromise between the most sensitive system (microsomal incubation of BP and DNA) and the biologically most relevant system (in vivo).     

Lack of platelet factor-3 activation after incubation of platelet-rich plasma with kaolin in the rat.

Stypven times, measured in rat platelet-rich plasma (P.R.P.) after incubation with kaolin, did not shorten as incubation proceeded, thus reflecting the lack of development of platelet factor-3 (PF3) availability in this test system. Repeated freezing and thawing of P.R.P. or aggregation with collegan did result in PF-3 availability. Aggregation and PF-3 availability were inhibited by the compound VK774. These findings add another aspect to the list of species differences in platelet function.     

Cytoplasmic contaminants in Triton X-100 washed rat liver nuclei - a possible way of further purification.

The presence of cytoplasmic contaminants is demonstrated in preparations of rat liver nuclei, even after washing with Triton X-100. They can be removed by incubation at 37 degrees C in a medium of low-salt concentration.     

Steroid metabolism by mouse preimplantation embryos in vitro.

Mouse preimplantation embryos were incubated with radioactive pregnenolone, progesterone or dehydroepiandrosterone for various periods of time. These substrates were not converted to metabolites even after incubation of 120 h. We suggest that preimplantation mouse embryo does not possess enzyme activities for steroid metabolism.     

The electrophoretic mobility of serum lysozyme.

The electrophoretic mobility of serum lysozyme in 2 patients with raised enzyme levels was identical to that of gamma-globulins. Similar mobility was observed after incubation of lysozyme and normal serum. Incubation with one hypogammaglobulinemic serum showed that lysozyme could also acquire alpha2 mobility.     

Some properties of the goat placental lactogen.

Goat placental lactogen was partially purified from a medium collected after placental tissue incubation. The data obtained by disc electrophoresis and isoelectric focusing experiments, as well as by means of radioreceptor assay methods, provide evidence of the similarity between the goat and ovine placental lactogen.     

Lack of platelet factor-3 activation after incubation of platelet-rich plasma with kaolin in the rat

Summary Stypven times, measured in rat platelet-rich plasma (P. R. P.) after incubation with kaolin, did not shorten as incubation proceeded, thus reflecting the lack of development of platelet factor-3 (PF₃) availability in this test system. Repeated freezing and thawing of P. R. P. or aggregation with collagen did result in PF-3 availability. Aggregation and PF-3 availability were inhibited by the compound VK774. These findings add another aspect to the list of species differences in platelet function.This study was partly supported by a grant from I. W. O. N. L.     

An actin-destabilizing factor is present in human plasma.

Plasma and serum of humans or experimental animals contain a factor which destabilizes F-actin. The factor has no DNAse or thrombin activity and after incubation with F-actin does not modify the position of the actin band on a SDS polyacrylamide gel. Hence it probably depolymerizes F-actin.