The analysis of fatty acids and their derivatives in the liver of C57BL/6 mice with long-term caloric restrictions

Caloric restriction (CR) is a dietetic intervention based on the reduction of daily calorie intake by 10-30 %. When subjected to CR, the organism adjusts its metabolism to the changing availability of key nutrients. However, fatty acids' content in organisms subjected to long-term CR has not been evaluated. The aim of the research was to analyze the influence of long-term CR on the contents of medium- and long-chain fatty acids, as well as on the contents of fatty acid derivatives in liver. The study was performed on C57BL female (n = 12) and male (n = 12) mice subjected to lifelong 30 % calorie restriction. Fatty acids were analyzed using gas chromatography, while fatty acid derivatives were analyzed with liquid chromatography. The dynamics of change of the lipid profile of the labeled fatty acids observed in the liver tissue confirms that lipolysis actively takes place in this organ when hungry. Moreover, it is highly possible that de novo synthesis of acids takes place, with the aim to ensure energy substrates to the body. Moreover, an increase of concentration was observed for fatty acid derivatives, those with anti-inflammatory properties (resolvin, LTX A4). However, there was no increase in the concentration of pro-inflammatory eicosanoids. The results suggest that it is important to take into consideration the introduction of appropriate supplements when using CR.

The analysis of oral nutritional supplements related aspects among patients with digestive system cancer

OBJECTIVE: Malnutrition-related disease particularly occur in patients with digestive system cancer. The administration of oral nutritional supplements (ONSs) is one of the methods of nutritional support recommended for oncological patients. The primary aim of this study was to assess the consumption-related aspects of ONSs among patients with digestive system cancer. The secondary aim was to assess the impact of ONSs consumption on the quality of life of these patients. PATIENTS AND METHODS: The current study included 69 patients with digestive system cancer. The assessment of ONSs-related aspects among cancer patients was conducted using a self-designed questionnaire, which has been accepted by Independent Bioethics Committee. RESULTS: Among all patients, 65% of participants declared that they consumed ONSs. Patients consumed various types of ONSs. However, the most common were protein products (40%) and standard products (37.78%). Only 4.44% of patients consumed products with immunomodulatory ingredients. Nausea was the most commonly (15.56%) observed side effect after ONSs consumption. Considering particular types of ONSs, side effects were the most commonly declared by patients who consumed standard products (p=0.157). The easy product availability in the pharmacy was noted by 80% of participants. However, 48.89% of patients assessed the cost of ONSs as not acceptable (48.89%). 46.67% of studied patients did not observe the improvement of quality of life after ONSs consumption. CONCLUSIONS: We have demonstrated that patients with digestive system cancer consumed various period, amount, and types of ONSs. Side effects after ONSs consumption occur rarely. However, the improvement of quality of life related to ONSs consumption was not noted in almost half of participants. ONSs are easily available in pharmacy.

Graphical Abstract

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The potential of gut microbiome as a non-invasive predictive biomarker for early detection of pancreatic cancer and hepatocellular carcinoma

OBJECTIVE

The aim of this paper was to discuss the potency of gut microbiome as a non-invasive predictive biomarker for early detection of pancreatic cancer and hepatocellular carcinoma.

MATERIALS AND METHODS

We analysed the available up-to-date literature (PubMed, Embase, Google Scholar databases) regarding the link between gut microbiome and early detection of pancreatic cancer, as well as hepatocellular carcinoma. The following search linked to gut microbiome and aforementioned cancers was used: 'gut microbiome', 'gut microbiota', 'pancreatic cancer', 'pancreatic ductal adenocarcinoma', hepatocellular carcinoma', 'microbial biomarkers', 'fungal microbiota', 'mycobiota'.  The search was conducted in English.

RESULTS

The association between gut microbiota imbalance and development of pancreatic cancer and hepatocellular carcinoma has been recognized during last several years. The most common type of pancreatic cancer is pancreatic ductal adenocarcinoma, whose carcinogenesis is strongly related to oral microbial dysbiosis, H. pylori infection, bactibilia, hepatotropic viruses, and intrapancreatic microbiota. It is known that gut-liver axis exists and may affect hepatocarcinogenesis. Currently, the treatment strategies of these cancers are strongly limited and there are not well-recognized screening tools to early diagnose them. The growing attention towards the use of gut microbiome as a predictive non-invasive biomarker to detect pancreatic cancer and hepatocellular carcinoma in early stage has been observed.

CONCLUSIONS

To conclude, the field regarding the link between gut microbiome as a non-invasive biomarkers and early detection of pancreatic cancer and hepatocellular carcinoma exists, however, it is not well-investigated. Additionally, many of the studies were conducted with small sample sizes, whereas biomarkers are ethnicity-dependent and should be validated in wide range of populations. Nevertheless, these aspects are promising and open up new diagnostic options.

Lipoxin (LTX A4 5S, 6R, 15R) levels drastically decrease after 5 years of hemodialysis treatment

The increased risk of atherosclerosis in patients with chronic kidney disease (CKD) is associated with the increased concentration of fatty acids from the omega-6 family. Products of arachidonic acid oxidation, including prostaglandins, thromboxanes, hydroxyleicosa-tetraenoic acids (HETES) and hydroxyoctadecadienoic acids (HODES) are involved in the pathogenesis of cancer and cardiovascular diseases due to increased oxidative stress. The aim of our study was to determine the relations resulting from the duration of CKD treatment. One of our main concerns is, whether and when the cascade of synthesis of inflammatory mediators may be insufficient in patients with CKD during many years of treatment. The study involved 121 patients with CKD and 87 healthy volunteers. Eicosanoid profiles 9(S)-HODE, 13(S)-HODE, 5(S)-HETE, 12(S)-HETE, 15(S)-HETE, 5(S)-oxoETE, 16(RS)-HETE, and 5(S),6(R)-lipoxinA4, 5(S),6(R),15(R)-lipoxinA4 were extracted in plasma. The HPLC separations were performed by means of 1260 liquid chromatography. Patients with CKD have a significantly higher concentration of the following inflammatory mediators: 13(S)-HODE, 5(S)-HETE, 12(S)-HETE, 15(S)-HETE, 5(S)-oxoETE, 16(RS)-HETE, and 5(S),6(R), 15(R)-lipoxinA4 relative to the control group. However, the concentrations of 9(S)-HODE were lower in the CKD group. The comparison of sexes did not show significant differences in terms of CKD. A tendency for lower concentrations of HETE and HODE were observed in the group of men. 15LOX, 12LOX and 5LOX pathways in chronic kidney disease are increased, while COX are suppressed (9-HODE). The analysis of the treatment time of patients with CKD shows that incorrect levels of 5(S), 6(R) and 15(R)-lipoxinA4 are developed. We present a new evidence of possible concepts and future clinical interventions in patients suffering from chronic kidney disease for many years. These data for the first time demonstrate that lipoxin levels drastically decrease in the course of CKD. Therefore, synthetic LXA4 analogues may be used as an antioxidant therapy in CKD, which requires further research.

Conjugated linoleic acids diminish glycogen synthase and glycogen synthase kinase-3 expression in muscle cells of C57BL/6J mice - in vitro and in vivo study

Conjugated linoleic acids (CLA) have been extensively advertised as dietary supplements to reduce fat and increase muscle mass. However, the role of CLA in glycogen metabolism is still largely unknown. The aim of this study was to assess the effect of CLA on glycogen synthesis in vitro (CCL 136 cell line human) and CLA in vivo (C57BL/6J mice). The materials used were the CCL 136 muscle cell line and muscles of female C57BL/6J mice (n = 52), housed at animal laboratory facility and feed with "MURIGRAN", a standard feed prepared for rodents (Agropol, Poland). Chemically pure fatty acids were added to soybean oil. CLA isomers (c9,t11 CLA, t10,c12 CLA, and as a mixture (1:1)) were administered with feed. Supplementation in mice started at week 6 of age and lasted for 4 weeks. Methods used in the study were real time- PCR - quantification of gene expression, Western blot glycogen synthase kinase-3 (GSK3α 9) and glycogen synthase (GS) protein, glycogen staining by PAS. Quantitative determination of glycogen by spectrophotometry and intracellular reactive oxygen species was measured the intracellular oxidation of dichloro-dihydro-fluorescein diacetate (DCFH-DA). In vitro data showed that GS and GSK3 expression was lower in cells cultured with different CLAs and a mixture of CLAs. GS gene expression was significantly decreased in cells cultured with c9, t11 CLA (P < 0.04) and t10, c12 CLA (P < 0.05) as well as the mixture of both isomers. The GSK3α gene expression was reduced in cells cultured with a mixture of CLA (P < 0.02), whereas phosphorylation of GSK3α increased in cells cultured with c9, t11 CLA GSK3α (P < 0.05). In vivo data showed a reduction in the glycogen concentration among mice fed a diet containing t10, c 12 CLA and a mixture of CLA isomers. We conclude that both CLA isomers can affect the synthesis of glycogen in muscle cells through the regulation of GS and GSK3α gene expression.

Modulatory effect of inulin with soya isoflavones on plasma lipid profile and liver SCD-18 index in rats with induced type-2 diabetes mellitus

Obesity and type-2 diabetes are often associated with nonalcoholic fatty liver disease (NAFLD). Soya isoflavones act as antidiabetic agents and protect against NAFLD. There are data suggesting that inulin may increase the plasma concentration and effect of soya isoflavones. The aim of the present study was to compare the effect of soya isoflavones, as opposed to the effect of soya isoflavones with inulin, on plasma lipid profile, liver morphology, and liver fatty acids in rats with induced type-2 diabetes mellitus. Data were collected on thirty-six male Sprague-Dawley rats divided into control and diabetic groups. Animals in the diabetic (DM) group were on a high-fat diet and were injected with low doses of streptozotocin. Animals in the control groups were fed a regular diet and were injected with a buffer. After the injections, the animals were divided into three groups of nondiabetic rats (nDM)-controls (c-nDM), rats treated with isoflavones (IS-nDM), and rats treated with isoflavones plus inulin (IS+IN-nDM)-and three parallel diabetic (DM) subgroups: controls (c-DM), rats treated with isoflavone (IS-DM), and rats treated with isoflavones plus inulin (IS+IN-DM). Hepatic steatosis and fibrosis were examined using hematoxylin-eosin staining and Mallory's trichrome methods respectively. Liver fatty acids were extracted and analyzed by gas chromatography. A lipid blood test was performed. The study showed significant changes in liver fatty acids, liver morphology, and plasma lipid profile. The estimated SCD-18 index significantly decreased in both the control and DM groups after isoflavone supplementation. The level of liver steatosis and fibrosis also decreased after isoflavone supplementation in the DM groups. The plasma lipid profile showed increased levels of HDL-C after isoflavone supplementation in the DM groups. These results support the protective use of isoflavones in liver steatosis and as beneficial to plasma lipid profile in individuals with diabetes. A novelty of this work is its comparison of supplementation using soya isoflavones with supplementation using both soya isoflavones and inulin. Surprisingly, additional supplementation with inulin modulates the positive effect of isoflavones.

Diverse inhibition of forkhead box O1 activity by linoleic acid isomers - potential role in lipid metabolism in HepG2 cells and livers of C57BL/6J mice

Conjugated dienes of linoleic acid (CLA) are constitutional and geometric isomers of linoleic acid that are commonly used as dietary supplements during body mass reduction. Their role in the reduction of lipid deposits in liver tissue is not unequivocal. CLA contain an equimolar mixture of two isomers of linoleic acid: trans-10,cis-12 CLA and cis-9,trans-11. Only one isomer - trans-10,cis-12 CLA exhibits fat-reducing properties, cis-9,trans-11 CLA does not. The main goal of this study was to determine if CLA isomers affect the activation of forkhead box O1 (FoxO1) in liver cells and tissue. FoxO1 is a protein that plays a crucial role in regulation of lipid and carbohydrates metabolism. In vitro and in vivo models of our study were HepG2 cells and C57BL/6J mice. Methods used in the study were qPCR - quantification of FoxO1 gene expression, Western blot - posttranslational phosphorylation of FoxO1, Oil Red O (ORO) - lipid staining and ELISA - quantification of apoB100. In both models trans-10,cis-12 CLA diminished FoxO1 gene expression: decrease by 44.1 ± 20.9% SD in the cells and 65.4 ± 29.8% SD in mice. The lowest accumulation of lipids (drop of 37.2 ± 1.7% SD) and the highest increase of apoB100 protein (74 ± 12.8% SD) were detected in the medium of cells cultured with trans-10,cis-12 CLA. Both isomers of linoleic acid have different effects on lipid metabolism. Isomer c9,t11 CLA accelerates lipogenesis, whereas isomer t10,c12 CLA activates secretion of lipids in HepG2 cells. In contrast to the in vitro study, unfortunately this pro-health property of t10,c12 CLA was not confirmed in the in vivo model. This casts a shadow on CLA dietary supplements that are commonly used among people with type 2 diabetes, NAFLD (non-alcoholic liver disease) or a metabolic syndrome in order to lose weight.

The short chain fatty acids and lipopolysaccharides status in Sprague-Dawley rats fed with high-fat and high-cholesterol diet

Short chain fatty acids (SCFA) are produced by the gut microbiota during the fermentation of non-digestible polysaccharides. Diet is a major factor driving the composition and metabolism of the colonic microbiota. The aim of our study was to examine how a fat-rich and cholesterol-rich diet that, which leads to many metabolic disorders, affects the SCFA profile and lipopolysaccharide (LPS) concentration. The experiment was carried out on 72 male, 8-weeks-old Sprague-Dawley rats. The study group (n = 30 rats) received high-fat and high cholesterol diet (HFHCh). The control group (n = 30) received standard food for laboratory rats. The rats from study and control groups were sacrificed after 4, 8, 12, 16 and 20 weeks after start of dietary exposure. The analysis of SFA in feces was performed using gas chromatography (Agilent Technologies 1260 A GC). The exposure to high-fat and high-cholesterol diet was associated with significant changes in SCFA levels. Relative to the control, each of HFHCh subgroup revealed a statistically significant decrease in butyrate (12.5% ± 5.7% versus 32.8% ± 9.1%) and an increase in propionate level (45.4% ± 6.2% versus 19.14% ± 7.1%). The ratio of acetate: propionate: butyrate was also changed (from 1.1: 0.6: 1 for control groups to 3 : 3,6 : 1 for HFHCh groups). The main SCFA in the HFHCh group was propionate instead of acetate. The dietary exposure resulted in significant differences in LPS concentration. After 12 weeks of HFD exposure, LPS concentration was significantly higher compared to control groups (P < 0.05). Our study showed that HFHCh diet affected butyrate and propionate production associated with an increase in LPS secretion. The hypothesis that observed changes could result in intestinal imbalance secondary to gut barrier dysfunction requires further studies.

Effect of IGF-I and TNF-α on intensification of steroid pathways in women with PCOS phenotypes are not identical. Enhancement of progesterone pathway in women with PCOS increases the concentration of TNF-α

OBJECTIVE

The aim of this study was to determine the correlations between the concentration of tumor necrosis factor (TNF-α) and insulin-like growth factor I (IGF-I) in each woman with polycystic ovary syndrome (PCOS) phenotypes based on the levels of androgen.

METHODS

Two groups of women with PCOS differing in their levels of androgens. The test group composed of 39 women with PCOS according to the Rotterdam criteria in their reproductive age. The hormonal levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), thyroid stimulating hormone (TSH), prolactin (PRL), androstenedione, testosterone (T), estradiol (E₂) and sex hormone binding globulin (SHBG) were measured. Correlations analysis were performed calculating Spearman's rank correlation coefficient of hormones with relation to TNF-α and IGF-I.

RESULTS

There was a medium positive correlation of IGF-1 with LH levels (p < 0.05) and negative medium correlation of TNF-α with of dehydroepiandrosterone (DHEA)-SO₄ levels (p < 0.05) only in group of PCOS women with elevated androgens.

CONCLUSION

Analysis of TNF-α showed that women with high testosterone negative correlation between level of TNF-α and the concentration of DHEA-SO4. Inflammatory state involving TNF-α in women with PCOS and high concentration of androgens is caused by intensified Δ4 (progesterone) pathway and omitted or limited Δ5 (dehydroepiandrosterone) pathway of testosterone biosynthesis.

Influence of physical effort on aortic stiffness in young male athletes

OBJECTIVE

The progression of cardiovascular disease is blunted by regular exercise training as a common non-pharmacological treatment. Recent findings have confirmed that central aortic pressure is more strongly related to cardiovascular events than brachial blood pressure. The aim of the study was to evaluate the influence of a single bout of significant physical effort on central aortic pressure and pulse wave velocity in young male athletes.

PATIENTS AND METHODS

The study group consisted of 16 healthy male athletes undergoing regular endurance training. The subjects of the study (21.6 ± 2.85 years of age) underwent a submaximal exercise test consisting of cycling for 30 minutes. Aortic pulse wave velocity (PWV) and derivatives (augmentation index set to 75 heart beats, AIx75; pulse pressure amplification, PPA), ejection duration (ED), subendocardial viability ratio (SEVR) and central blood pressure were examined before and after the exercise test Blood pressure and pulse waveform were evaluated in the supine position after a 15-minute rest by means of the oscillometric method the oscillometric method.

RESULTS

Comparing the rest condition to the period immediately following the exercise test, athletes showed lower central than peripheral systolic blood pressure both before (129 ± 11 mmHg and 112 ± 8 mmHg, respectively, p < 0.001) and after (130 ± 10 mmHg to 112 ± 8 mmHg, respectively, p < 0.001) the test. They also showed a decrease of ED from 339.7 ± 44.4 ms to 326.9 ± 41.4 ms (p < 0.02) and an increase of PPA from 136.2 ± 5.4% to 140.3 ± 5.0% (p < 0.02), whereas PWV, AIx75 and SEVR changed insignificantly.

CONCLUSIONS

We confirm that PPA is sensitive to an instant change in aortic elasticity. Furthermore, the hemodynamic response to a single physical effort composed of shorter ejection time and increased relative elasticity of the aorta prevents impairment of oxygen supply to the heart musculature.

Apolipoprotein E4 allele is associated with substantial changes in the plasma lipids and hyaluronic acid content in patients with nonalcoholic fatty liver disease

Fat may affect progression of liver damage in patients with non-alcoholic fatty liver disease (NAFLD). In this study we characterize the state of lipid metabolism in 22 patients with NAFLD and different Apo-E variants. Total concentration of plasma total fatty acids was quantified by gas chromatography, while their derivatives by liquid chromatography/tandem mass spectrometry (LC ESI MS/MS). The ratio of plasma saturated fatty acid to monounsaturated fatty acid increased, whereas the ratio of polyunsaturated fatty acids to saturated fatty acids was reduced in Apo-E4 carriers. Simultaneously, the levels of individual plasma linoleic, arachidonic, and alpha linolenic acids significantly increased in subjects with the Apo-E4 allele. The 15-lipoxygenase metabolite, 13-hydroxyoctadecadienoic acid, was significantly higher in Apo-E3 carriers (p<0.006). 5-oxo-6,8,11,14-eicosatetraenoic acid was significantly elevated in Apo-E4 carriers (p<0.009). A significant difference in hyaluronic acid concentration (p<0.0016) as well as predicted advanced fibrosis (using the BARD scoring system) was found in Apo-E4 carriers (p<0.01). We suggest that a distinct mechanism of fibrosis between Apo E alleles. In Apo-E4 carriers, an elevation in 5-oxo-6,8,11,14-eicosatetraenoic acid synthesis and fatty acid dysfunction may induce fibrosis, while an inflammatory process may be the main cause of fibrosis in Apo-E3 carriers.

Fluoride in low concentration modifies expression and activity of 15 lipoxygenase in human PBMC differentiated monocyte/macrophage

Epidemiological and experimental evidences demonstrate positive correlation between environmental and occupational fluoride exposure and risk to various cardio-respiratory disorders. That fore we decided to examine the effect of fluorides on activity and expression of 15LOX enzyme which is implicated in biosynthesis of inflammatory mediators. Expression of 15LOX-1 and -2 enzymes mRNA and protein was analyzed using RT PCT and immunoblotting methods respectively whereas HPLC method was used to measure the levels of 15 lipoxygenases end products. Additionally AA and LA concentration in cells was measured using GC method. We observed that fluoride in small concentration may significantly decrease activity of 15LOX-1 and -2 in human PBMC macrophages and then concentration of its end products: 15-HETE, 12-HETE and 9+13-HODE, what may cause development of inflammation through the cholesterol arrest into the macrophages and its differentiation to foam cell. Noted by our team overexpression of the 15LOX-1 enzyme in macrophages after addition of lowest fluoride concentrations (1 and 3 μM) may be aimed at fighting inflammation development and excessive intracellular lipid accumulation. But highest fluoride concentrations (6 and 10 μM) added to cell culture slowly declined expression of this enzyme probably because of developing inflammation. Additional 15LOX-2 expression in macrophages after fluoride addition was low in 1 and 3 μM concentrations, but increased significantly after 10 μM fluoride addition what may suggest developing acute inflammation, because 15LOX-2 is associated to increased local hypoxia. This study indicated that even in small concentrations fluorides changes the amounts and activity of 15 LOX-1 and -2 enzymes taking part in the development of inflammatory process.

Activation of phospholipase A(2) by low levels of fluoride in THP1 macrophages via altered Ca(2+) and cAMP concentration

Phospholipases (PLA's) participate in the regulation of physiological and pathological processes in the cell, including the release of pro-inflammatory mediators and stimulation of inflammatory processes. It is also well known that fluoride can increase the inflammatory reactions. Therefore we decided to examine the effect of fluorides in concentrations determined in human serum on cPLA(2) and sPLA(2) activity. The incubation of macrophages in fluoride solutions significantly increased the amount of synthesized cellular cAMP, intracellular calcium and sPLA(2) activity in a dose-dependent pattern. The cPLA(2) activity, estimated by the amount of released arachidonic acid, increased significantly when 10 μM NaF was used. The results of our study suggest that fluoride may change the activity of phospholipases in macrophage cells. Probably, increased cAMP concentration activates protein kinase C (PKC) and thus stimulates PLA(2). cAMP also regulates the passage of Ca(2+) through ion channels, which additionally influence PLA(2) throughout Ca(2+)-calmodulin dependent protein kinase.

Prostaglandin E2 (PGE2) and thromboxane A2 (TXA2) synthesis is regulated by conjugated linoleic acids (CLA) in human macrophages

Conjugated linoleic acid (CLAs) are positional and geometric isomers of linoleic acid with have a potential anti-atherosclerotic and anti-inflammation properties. Metabolites of arachidonic acid--prostaglandins and thromboxans--are endogenous mediators of inflammation. Prostaglandin E(2) and thromboxan A(2) which are a products of two izoformes of cyclooxygenases (COX-1 and COX-2) in macrophages, play an important role in this process. COX-1 is a constitutive enzyme, whereas the COX-2 is inducible and its amount in the cell rapidly increases during inflammation (e.g. via NF kappaB pathway). The aim of the study was to test the effect of CLAs on cyclooxygenases (COX-1 and COX-2) activity, their mRNA expression and protein content in macrophages. Additionally the active form of the kappaB (NF kappaB) transcription factor was measured. For the experiments monocytes from monocytic cell line (THP-1) and from human venous blood were used. Monocytes were differentiated to macrophages and cultured with 30 muM CLAs or linoleic acid for 48 h. The COX-1 and COX-2 products - PGE(2) and TXB(2), were measured by ELISA method. The enzymes (COX-s) activity were estimated by spectroscopic method. mRNA expression and protein analysis were analysed by real-time PCR and Western blot technique. In macrophages cultured with CLAs reduction of TXB(2) and PGE(2) concentration was observed. Significant change in COX-2 expression in cells cultured with trans-10, cis-12 CLA (in macrophages obtained from peripheral blood) was observed. COX-1 inhibition was resulting from competition of CLA and linoleic acid with arachidonic acid.

Exchange of unsaturated fatty acids between adipose tissue and atherosclerotic plaque studied with artificial neural networks

The linoleic C18:2 (n-6) and linolenic C18:3 (n-3) are recognized as essential components of the diet. Free radical peroxidation of essential fatty acids (EFAs) present in lipoproteins produces oxidized low-density lipoproteins which play a critical role in the development of atherosclerosis. The accumulation of EFAs in the vascular wall and correlations between their content in the adipose tissue and atherosclerotic plaque have been confirmed. The present study was undertaken to determine the usefulness of a neural network for studying the exchange between tissues of linoleic, alpha-linolenic, and arachidonic acids-three fatty acids with a well-understood metabolism. Atheromatous plaques, adipose tissue, and serum were obtained from 31 patients who underwent surgery due to atherosclerotic stenosis of the abdominal aorta, iliac or femoral arteries. Fatty acids were extracted and separated as methyl esters using gas chromatography. Statistical analysis was done with STATISTICA neural networks package. Several correlations reported previously were corroborated and factors modifying the content of individual EFAs in adipose tissue and atherosclerotic plaque were revealed. Artificial neural networks (ANNs) were used to determine factors modifying the content of linoleic, alpha-linolenic, and arachidonic acids in human atheromatous plaques. The mechanism of exchange of some fatty acids between the adipose tissue, atheromatous plaque, and plasma is discussed. The results provide evidence for an effective mechanism of tissue uptake and turnover of linoleic acid. Reduced plasma levels of this acid are compensated by release from adipose tissue and atheromatous plaque. While alpha-linolenic acid is continuously taken up by the plaque, adipose tissue absorbs this acid to a certain level only. The dynamics of exchange of arachidonic acid between adipose tissue and atheromatous plaque reflects a minor role for adipose tissue in determining plaque content of this acid, suggesting that "de novo" synthesis is the chief source of arachidonic acid in plaques.

[The Mediterranean diet: cultural factor or prevention of civilization diseases?]

Cardiovascular diseases and neoplasms are still the most frequent cause of morbidity. Abnormal diet is an important risk factor of the diseases. Therefore, there is a need to apply activities leading to changes in life style and nutrition. The most important features of the Mediterranean diet and the benefits by its use are described in this article.

[Trans isomers of unsaturated fatty acids--metabolic action and clinical effects]

Fatty acids with the trans configuration are formed chiefly during hardening of oils and have been associated with increased risk of ischaemic heart disease. Dietary uptake of such fatty acids increases the level of lipoprotein (a) and LDL cholesterol, at the same time reducing the level of HDL cholesterol in plasma. As the content of saturated fatty acids in margarine is lower than in butter, the former product was for a long time considered as healthier. However, some margarines are rich in trans fatty acids. In other words, the risk of cardiovascular diseases can only be reduced by replacing butter with margarine checked for a low trans fatty acid content. The purpose of this paper was to review the literature dealing with the metabolic actions of trans isomers of unsaturated fatty acids and their clinical effects.

[The effect of fluoride ion on the activity of succinate dehydrogenase isolated from the pig's renal cortex]

Succinate dehydrogenase is a membrane-bound mitochondrial enzyme providing the respiratory chain with electrons. In natural environment the enzyme is a part of the respiratory chain and slight changes in the content of phospholipids (during preparation) qualify the enzyme to ubiqinone reductase titer. The actual paper answers the question of how major, selected inorganic anions metabolically influence succinate dehydrogenase. The objective of the paper was to determine: 1) what influence on SDH activity is exerted by ionic strength; 2) how do fluoride, phosphate and chloride influence the activity of succinate dehydrogenase present in submitochondrial particles. Mitochondria were prepared on the basis of King's method. Mitochondria and submitochondrial particles were obtained from mitochondria isolated from the pig's kidney. The activity of enzyme was measured by polarographic method with the aid of phenasine methosulphate and dichloroindophenol. The protein concentration was determined by the Gornal's method. The following conclusions have been drawn, namely: The activity of enzyme is not modified by means of ionic strength (Fig. 1, 2, 3). Fluoride exerts influence on the enzyme as a competitive inhibition when the concentration of succinate in the sample is of the order 1 x 10(-3), 5 x 10(-4), 2 x 10(-4) mol/dm3, with concentrations of succinate higher than 2 x 10(-2), 2 x 10 mol/dm3 the fluoride ion behaves as a typical non-competitive inhibitor (Fig. 4). Phosphates modified the activity of enzyme, and exerted influence as its competitive inhibitor (Fig. 5, 6). In the process of SDH inhibition induced by fluoride ion there are two separately acting mechanisms which respectively involve one or two ions. As it has been found out their effect also depends on the amount of succinate in the environment. The first mechanism appears in condition of high succinate concentration in the solution (about 20 mmol/dm3), when the active centre of enzyme is completely saturated by the substrate. The by fluoride induced inhibition is of non-competitive character, which means that single F ion binds to enzyme outside its active centre (which is occupied by substrate). On the other hand, when the concentration of succinate is close to 1 mmol/dm3, under conditions of incomplete saturation of the active centre by substrate, the enzyme is being inhibited competitively, and, as indicated, 2 fluoride ions bind with it (Fig. 7, 8).