[Mutagenic aspects of the lipoprotein lipase gene]. / Aspecte mutagenice la nivelul genei lipoprotein lipazei.

Lipoprotein lipase (LPL) is an enzyme involved in the metabolism of triglyceride-rich lipoproteins (chylomicrons and VLDL), participating also in the remodeling of HDL particles. It is encoded by a gene located on chromosome 8 (8p22), containing 10 exons. Abnormalities in this gene lead to the development of LPL enzyme deficiency. About 100 mutations have been described in the LPL gene, the most frequent being Asp9Asn, Gly188Glu and Asn291Ser. Mutations in the homozygous form are associated with type I hyperlipoproteinemia (familial chylomicronemia). Mutations in the heterozygous state have a significant incidence in population (3-7%) and lead to a decrease in the LPL activity with up to 50%, which causes the modification of the plasma lipid profile, meaning an increase in triglycerides and a decrease in HDL cholesterol. Both modifications represent cardiovascular risk factors, so that the carriers of LPL gene mutations have an increased predisposition to develop coronary heart disease. Moreover, the association of heterozygous mutations in the LPL gene in individuals with genetic-type hyperlipoproteinemias may aggravate the perturbations of the lipid profile and, consequently, they can increase the cardiovascular risk in these patients. The accumulated data may be considered an argument for the importance of investigating LPL gene mutations in the population, in order to detect precociously the individuals with an increased atherogenic predisposition and to decide on the appropriate therapy.

[Method for the molecular diagnosis of lipoprotein lipase genetic deficiency]. / Metoda de diagnostic molecular al deficitului genetic al lipoprotein lipazei.

Modifications of plasma lipid profile is one of the major causes of a high cardiovascular risk. They can be the consequences of mutations in the gene encoding lipoprotein lipase (LPL), an enzyme that has an important role in the metabolism of plasma lipoproteins. The aim of the present study was to put into practice a method for detecting the Gly188Glu mutation in the LPL gene. The search was performed on a group of 107 patients with cardiovascular diseases and/or dyslipidemias. DNA investigation consisted, in a first stage, in the enzymatic digestion of exon 5 of the LPL gene, previously amplified by the PCR reaction, with the AvaII restriction endonuclease. Three of the subjects were further investigated by the sequencing of exon 5, in order to search for the presence of other mutations. We didn't detect the Gly188Glu mutation in none of the cases, and no other mutation in exon 5 was found in the three patients tested by DNA sequencing. We conclude that the amplification-restriction method can be used for the detection of known mutations in the LPL gene, allowing an early identification of the subjects with a high cardiovascular risk and the onset of the appropriate therapy. In order to detect mutations which don't affect the recognition sequence of a restriction enzyme and eventually new mutations, the sequencing of that gene is recommended.

[Electron microscopy in oral squamous cell carcinoma of elderly patients]. / Aspecte electronomicroscopice în carcinoamele cavitatii orale la pacientii de vârsta a treia.

OBJECTIVES: Squamous cell carcinoma is the most frequent tumor occurring in the oral cavity. The aim of the study is to point out the fine-structural characteristics of the tumor cells and of the adjacent stromal cells, trying to establish a correlation between these characteristics and the biological behavior of the tumor. MATERIAL AND METHODS: We performed an electron microscopic investigation for tree elderly patients diagnosed with oral squamous cell carcinoma. RESULTS: The tumoral cells presented nuclear abnormalities and the reduction of the intercellular cohesion, through an increase in the intercellular spaces, and desmosomal modifications. Through the abundance and the variety of the cellular types, the stromal component represented a positive response from the host. CONCLUSIONS: In the diagnosis of the oral carcinoma, the electron microscopic exam supplements the light microscopic investigation, revealing important morphologic elements at a subcellular level (regarding the nucleus, cellular organelles, and junctions).

[Molecular mechanisms of apoptosis. Fas and TNF systems. ICE protease system. Bcl-2 family]. / Mecanismele moleculare ale apoptozei. Sistemul Fas si sistemul TNF. Sistemul proteazelor ICE. Familia Bcl-2.

For every cell is a time to live and a time to die. The cell death that occurs during embryogenesis, normal tissue turnover, pathological conditions like cancer cells, etc. is "programmed cell death" or apoptosis. In this study we report on apoptosis mediated by cytokines. Fas ligand and tumor necrosis factor bind to their receptors and induce apoptosis.

[Physiological and pathological roles of apoptosis]. / Roluri fiziologice si patologice ale apoptozei.

An understanding of the cellular events leading to apoptosis is important for the design of new chemotherapeutic agents directed against the types of leukemias and lymphomas that are resistant to currently used chemotherapeutic protocols. Malignant cell proliferation and accumulation depend on an imbalance between the rate of cell production and the rate of cell death. Apoptosis has been demonstrated to be involved not only in the regulation of normal tissues but also in the development and control of tumour cells. The relationship between oncogenes, apoptosis and growth factors is very important in determining prognosis when analysing the potential benefits of different treatment regimens.

[Periodontitis, a risk factor for cardiovascular diseases?]. / Periodontitele, factor de risc pentru bolile cardiovasculare?

Exist a statistically significant association between a diagnosis of coronary heart disease and certain oral health parameters. These parameters are independent and more strongly associated with coronary heart disease than were recognized risk factors, such as serum cholesterol levels, body mass index, diabetes and smoking status. The correlation between serum and salivary cholesterol concentration and the role of salivary lipids in oral health have been poorly characterized. Lipids in saliva are mostly glandular in origin, through some may diffuse diffuse directly from the serum. The surface of the enamel (in case of dietary fat which have an cariostatic effect) is protected against demineralization by a mixture of salivary lipids and proteins. Salivary lipids may have anucleating role in the early mineralization of the dental plaque. The prevalence of periodontal disease may be increased in patients with atherosclerosis, and dental and periodontal infections have been shown to be associated with occurrence of acute and chronic coronary heart disease. Among the known risk factors of atherosclerosis, high serum lipid levels, especially cholesterol may be important with regard to periodontal health.