[Effect of smoking on lipoprotein metabolism].

Introduction: Recent aspects concerning effects of smoking on lipoprotein metabolism are presented as well as their harmful effects on blood vessels. It has been proved that smoking stimulates oxidation of LDL particles, producing a significant increase of triglycerides and a decrease of HDL-cholesterol, mostly due to HDL, subfraction diminution.

Lipid And Lipoprotein Disorders: Changes of other lipid and lipoprotein parameters are not significant and may even not be found in certain investigations.

Mechanism and control of degradation and resynthesis of adenylates in tumour cells.

A comparative study revealed that Ehrlich ascites carcinoma (EAC) cells use glutamine plus inosine for regeneration of adenylates via the purine nucleotide cycle, whereas AS 30D hepatoma cells use adenosine instead. This observation can be correlated with the very low production of aspartate from glutamine in hepatoma cells. Although glucose is an important energy fuel for EAC, it cannot maintain a high enough level of adenylates unless glutamine is also present.

Control and function of the transamination pathways of glutamine oxidation in tumour cells.

Parallel investigations of the transamination pathways of glutamine oxidation in Ehrlich ascites carcinoma (EAC) and AS 30D hepatoma revealed that hepatoma cells, unlike EAC, produce very little aspartate. This cannot be explained by differences in the activity of glutamine-metabolizing enzymes. Also, the mitochondria from the hepatoma respired at a similar rate to EAC mitochondria with glutamine as sole substrate producing substantial amounts of aspartate.

[Kinetics of degradation and resynthesis of the adenine-nucleotide pool in tumor cells].

Starting from the assumption that tumor cells constantly experience transient ischemia and anoxia, and that this results in metabolic stress which is reflected above all, on the concentration of ATP, ADP and AMP, in other words, the adenine nucleotide pool (AdN), the aim of our research was to study the degradation and resynthesis kinetics of that pool on two types of malignant cells. All experiments were conducted in vitro with cells of the transplantable tumors of Ehrlich's ascitic carcinoma and the AS 30D hepatoma, and metabolite analyses were carried out enzymatically or by way of the HPLC chromatography method. It was found that immediately after the setting on of anoxia, there comes not only to a fall in ATP, but also to a fall in the complete adenine nucleotide pool for about 50%.