Chronic administration of ethanol with high vitamin A supplementation in a liquid diet to rats does not cause liver fibrosis. 2. Biochemical observations.

The inability of the 'ethanol/high vitamin A Lieber-DeCarli diet' to induce liver fibrosis in two different rat strains was further evaluated by determining changes in parameters of liver cell damage and of retinoid and lipid metabolism. In the ethanol/vitamin A-treated group, slight but constant hepatic cell damage, as indicated by elevated alanine aminotransferase, aspartate aminotransferase and glutamate dehydrogenase activities in blood, was already observed at 6 months and maintained until the time of death at 16 months. Serum gamma-glutamyl transaminase activities were not raised.

Chronic administration of ethanol with high vitamin A supplementation in a liquid diet to rats does not cause liver fibrosis. 1. Morphological observations.

Rats of two strains (BN/BiRij and WAG/Rij) were fed the ethanol-containing Lieber-De Carli liquid diet supplemented with high amounts of vitamin A for 16 months. In contrast to Lieber and co-workers, who showed liver fibrosis developing within 9 months on the same diet in Sprague-Dawley rats, we were unable to demonstrate a histological and biochemical increase in liver collagen in either strain. Steatosis was present to a varying degree in both strains in ethanol-treated rats, but also in control animals.

Monoclonal gammapathies in long-term surviving rhesus monkeys after lethal irradiation and bone marrow transplantation.

Late effects of total body irradiation and subsequent autologous bone marrow transplantation on the development of age-related monoclonal gammapathies (MG) were studied in 14 long-term surviving Rhesus monkeys. Together with 27 untreated control monkeys, they have been followed up for more than 20 years. In contrast with the control group, the experimental monkeys developed MG with aging in higher frequencies, earlier and mainly of the benign MG category.

Induction and disappearance of DNA single-strand breaks in human B and T lymphocytes after exposure to ethylnitrosourea.

Using the alkaline filter elution technique we monitored the induction and disappearance of DNA single-strand breaks (SSB) in 3 different human lymphocyte populations: (1) freshly isolated peripheral blood lymphocytes (PBL); (2) B and T cell-enriched lymphocyte fractions; and (3) actively proliferating T cells, after exposure to ethylnitrosourea (ENU). Between these different lymphocyte populations no significant differences were observed in the number of SSB induced by a 20-min treatment with 0.5 mM ENU.

Decreased DNA repair capacity in familial, but not in sporadic Alzheimer's disease.

Using the alkaline filter elution technique we determined the induction and disappearance of DNA single-strand breaks (SSB) in freshly isolated peripheral blood lymphocytes (PBL) from 43 Alzheimer's disease (AD) patients and 48 normal, healthy age- and sex-matched control subjects following in vitro exposure to N-ethyl-N-nitrosourea (ENU). The mean percentage SSB disappearance in PBL from control subjects at 1 h after ENU treatment was 41.4 +/- 2.

Induction and disappearance of DNA strand breaks and/or alkali-labile sites in human lymphocytes exposed to N-ethyl-N-nitrosourea.

We investigated the induction and disappearance of DNA lesions that are detected as single-strand breaks (SSBs) with the alkaline filter elution technique, in human peripheral blood lymphocytes (PBLs) following exposure to N-ethyl-N-nitrosourea (ENU). In PBLs of the 15 individuals studied, 35 +/- 16% (mean +/- SD) of the SSBs present at the end of a 20 min treatment disappeared within 1 h; up to 24 h post-treatment no further disappearance was observed. Interindividual differences in SSB disappearance were considerable; in two cases, almost no SSBs disappeared over the 1 h period.

Induction and disappearance of DNA strand breaks in human peripheral blood lymphocytes and fibroblasts treated with methyl methanesulfonate.

The induction and disappearance of DNA single-strand breaks (SSB) in human peripheral blood lymphocytes (PBL) and fibroblasts exposed to methyl methanesulfonate (MMS) were investigated by using the alkaline filter elution assay. In the two cell types, identical amounts of SSB were induced during a 45-min treatment with a given dose of MMS. In quiescent PBL only 9 +/- 4% (mean +/- SD) of the induced SSB had disappeared at 1 h after exposure, whereas in phytohemagglutinin-stimulated PBL, 23 +/- 12% disappeared within the same repair period.

Immune regulation of 5T2 mouse multiple myeloma. II. Immunological treatment of 5T2 MM residual disease.

The transplantable murine 5T2 multiple myeloma (MM) has been shown to be sensitive to idiotype-specific immunity, provided the recipient mice were immunized before transplantation. In the present study, anti-idiotype treatment was initiated after inoculation of the mice with 5T2 MM cells. Since in MM the serum idiotype concentration is far too high for anti-idiotype antibodies to reach the target cells, reduction of the MM to a minimal residual disease should be performed before.

Immune regulation of mouse 5T2 multiple myeloma. I. Immune response to 5T2 MM idiotype.

The transplantable murine multiple myelomas (MM) of the 5T series originated spontaneously in the aging C57BL/KaLwRij mice. These murine malignancies offer an excellent model for experimental studies on different aspects of the human disease. With the aim to look for new treatment modalities, the influence of idiotype-specific immune response on the 'take' and the development of the 5T2 MM was studied.

New methods for the detection of genetic variation.

The possibility to detect variations in the genetic material is limiting to measure DNA sequence variations occurring at low frequency, such as somatic mutations responsible for the generation of diversity in the immunoglobulin genes. In order to study mutations, a system has been developed using transgenic mice in which mutant genes are rescued and selected among non mutant genes by the phage lambda as shuttle vector. Moreover, it has been developed a two-dimensional DNA fingerprinting method based on the capacity to separate digested DNA on the size and base sequence.

Immunoblotting techniques for the detection of low level homogeneous immunoglobulin components in serum.

Because of the increasing demand for simple and reliable techniques for the detection of low concentrations of paraproteins against a highly heterogeneous serum background, two techniques were investigated for their sensitivity: isoelectric focusing (IEF) and Wieme high resolution electrophoresis, each with subsequent blotting by diffusion. The techniques were compared using isolated mouse monoclonal antibodies (mAb) of known concentration and specificity. Wieme electrophoresis in combination with immunoblotting (IBL) or antigen-specific immunoblotting (ABL) has a detection limit of 100 ng/ml and 10 ng/ml, respectively.

Comparative endotoxin-induced hepatic injury in young and aged rats.

Recent studies have demonstrated that aged rats are more susceptible to the lethal effects of endotoxin (ET) than young rats. The early (15 min to 7 h) hepatic ultrastructural and biochemical changes induced by ET in young (6 months) and aged (24 months) rats were evaluated to elucidate cell populations and/or the mechanisms that may be responsible for the previously observed differential effects. Aged rats given ET had significantly increased numbers of neutrophils in hepatic sinusoids at 30 min and thereafter as compared with ET-treated young rats.

DNA damage metabolism and aging.

As a result of permanent exposure to low levels of various endogenous and exogenous genotoxic agents, large numbers of lesions are continuously induced in the DNA of cells of living organisms. Such lesions could lead to dysfunction of cells and tissues, and they might well be the underlying cause of the age-related reduction of homeostatic capacity and the increased incidence of cancer and other diseases of old age. The rate of damage induction as well as the persistence of the lesions depends on the activity, efficiency and reliability of a wide variety of molecular defense systems.

mRNA levels and methylation patterns of the tyrosine aminotransferase gene in aging inbred rats.

We have examined the mRNA levels and methylation patterns of the liver-specific tyrosine aminotransferase (TAT) gene in inbred female rats aged 6, 24 and 36 months. Northern hybridization analysis of total RNA showed a 65% decrease in the steady state transcript level of TAT in the liver of 24- and 36-month old rats as compared to 6-month old animals. The TAT gene as studied by Southern hybridization analysis using the isoschizomers Hpa II and Msp I was found to be hypomethylated in the liver as compared to spleen and brain at six CpG sites within the gene.

The influence of ageing on the induction of the mRNAs of rat liver cytochromes P450IIB1 and P450IIB2.

To investigate the influence of age on the regulation of the cytochromes P450IIB1 and P450IIB2 the levels of the messenger RNAs for these two cytochromes were determined in liver cytoplasmic RNA of rats of various ages after maximal induction with either phenobarbital or isosafrole and in untreated rats. The levels of these mRNAs were determined by solution hybridization with a RNA-probe (riboprobe system) complementary to both mRNAs. This study showed a marked decrease in the maximal induction levels of these mRNAs between the ages of 12 and 36 months irrespective of the type of inducer used.

Light- and immunoelectron microscopic visualization of in vivo endocytosis of low density lipoprotein by hepatocytes and Kupffer cells in rat liver.

The in vivo interaction of low density lipoproteins (LDL) with the liver was investigated by visualizing the endocytic route using light- and immunoelectron microscopic methods in control and 17 alpha-ethinyl estradiol (EE)-treated rats. The fluorescent dye dioctadecyl indocarbocyanine perchlorate allowed the visualization of LDL at the light microscopic level. Cryoimmunocytochemistry using antibodies against apolipoprotein B was applied at the electron microscopic level.

Age-related monoclonal gammapathies: clinical lessons from the aging C57BL mouse.

In this article the long-held notion that benign monoclonal gammapathy (BMG) is a premalignant stage in the development of multiple myeloma (MM) is attacked. Jiri Radl argues that clinical and experimental observations indicate that they are separate entities which may be distinguished in the laboratory and which should be managed in radically different ways.

Increased levels of DNA breaks in cerebral cortex of Alzheimer's disease patients.

It has been hypothesized that Alzheimer's disease (AD) is caused by an accumulation of damage in DNA due to defective DNA-repair (21). Attempts to test this hypothesis by determining the activity of DNA-repair systems in nonneuronal cells from AD patients and controls so far provided conflicting results. An alternative approach is the direct comparison of DNA-damage levels in neuronal tissue of AD patients and controls.

The influence of age on the inducibility of rat liver cytochrome P450IA1 (CYPIA1) and P450IA2 (CYPIA2) mRNAs.

The levels of the messenger RNAs for the cytochromes P450IA1 (CYPIA1) and P450IA2 (CYPIA2) were determined in liver cytoplasmic RNA of rats of various ages after maximal induction with either 3-methylcholanthrene or isosafrole and in untreated rats. An increase in the CYPIA1 mRNA levels was observed only after treatment with 3-methylcholanthrene, whereas both 3-methylcholanthrene and isosafrole were able to induce the levels of CYPIA2 mRNA. The study presented here shows that the maximal induction of these 2 mRNAs did not change with age when 3-methylcholanthrene was used as the inducing agent.

Messenger RNA levels and methylation patterns of GAPDH and beta-actin genes in rat liver, spleen and brain in relation to aging.

Messenger RNA levels and methylation patterns of the glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) and beta-actin genes were studied in spleen, liver and brain of 6-, 24- and 36-month old female inbred rats. In the spleen, the mRNA levels of both housekeeping genes significantly increased between 24 and 36 months. No age-related alterations in the expression of GAPDH or beta-actin mRNA were observed in brain or liver.

The effect of age on the oxidative metabolism of antipyrine by uninduced microsomal fractions of rat liver.

The influence of ageing on the metabolism of antipyrine by different forms of cytochrome P-450 was studied in vitro, by measuring the formation of antipyrine metabolites by microsomes isolated from untreated rats, which were grouped into 5 different ages. Km, Vmax and Vmax/Km values were determined for the metabolites: 3-hydroxymethylantipyrine (HMA), norantipyrine (NORA) and 4-hydroxyantipyrine (OHA). Km values for all metabolites ranged from 2.