Differential influence of the lipid peroxidation product 4-hydroxynonenal on the growth of human lymphatic leukaemia cells and human periopherial blood lymphocytes.

The purpose of this study was to compare the influence of physiological and supraphysiological concentrations of 4-hydroxynonenal (HNE), a peroxidation product of omega-6-polyunsaturated fatty acids, on the proliferation of malignant CEM-NKR lymphatic leukaemia cells and normal human lymphocytes (HPBM). Furthermore the growth modulating effect of phytohemagglutinin (PHA) on both cell lines was examined. The effects of HNE were monitored 18 hours and 3 days after incubation, using two different DNA-synthesis assays ([3H]-thymidine- and BrdU- incorporation) and a mitochondrial dehydrogenases activity assay (MTT).

Interheavy disulfide bridge in immunoglobulin G (IgG) reacting with dithionitrobenzoate. A unique feature in serum proteins.

Immunoglobulin G (IgG) of many species contains 'labile' disulfide bonds (SS*), which within 24 h undergo a disulfide exchange with dithionitrobenzoic acid (NBSSBN). Aims of the present study were to detect directly this type of SS* groups by means of 14C-labelled NBSSBN, and to investigate its possible presence in other serum proteins. NBSSBN reacts during the first 30 min of incubation with free SH groups, and thereafter with the sulfur atoms of SS* groups.

Effect of oxidative stress by iron on 4-hydroxynonenal formation and proliferative activity in hepatomas of different degrees of differentiation.

It has been shown previously that oxidative stress by ferrous iron in vitro leads to an inhibition of proliferation of murine ascites tumour cells in vivo. This effect is associated with increased lipid peroxidation in terms of formation of the highly reactive aldehyde 4-hydroxynonenal (HNE), which has been shown to inhibit the proliferation of numerous tumours and to induce differentiation. It was the purpose of this article to study the occurrence and metabolism of HNE and its inducibility by oxidative stress in hepatomas of different degrees of differentiation to find further evidence for a possible role of HNE in proliferation and/or differentiation, because it is known that in hepatoma cells with a very low degree of differentiation basal lipid peroxidation is hardly detectable, while in normal hepatocytes the basal level of thiobarbituric acid reactive substances (TBArS) is rather high.

The effect of reduced physical activity on longevity of mice.

Reduced physical activity leads, in female mice, to a reduction of the average and maximal life span. The average age at death of the inactive experimental group was 497 +/- 121 days (mean +/- S.D.

A decrease in reactive disulfide bonds of serum IgG signals a characteristic change in the IgG subclass patterns of rats bearing experimental tumors.

Previous studies have shown that human IgG1 contains a 'reactive' disulfide bridge (SS*), detectable by a 24-hour disulfide exchange reaction, and that the serum level of this IgG subclass is selectively diminished in patients with various malignant diseases. Here we present evidence that in rats IgG2b is the only subclass that carries one SS* per molecule. Furthermore, it is shown that rats inoculated with experimental tumor lines, i.