Július Hodosy

Bacteria in gene therapy: bactofection versus alternative gene therapy

Recent advances in gene therapy can be attributed to improvements of gene delivery vectors. New viral and nonviral transport vehicles that considerably increase the efficiency of transfection have been prepared. However, these vectors still have many disadvantages that are difficult to overcome, thus, a new approach is needed. The approach of bacterial delivery could in the future be important for gene therapy applications. In this article we try to summarize the most important modifications that are used for the preparation of applied strains, difficulties that are related with bacterial gene delivery and the current use of bactofection in animal experiments and clinical trials. Important differences to the alternative gene therapy (AGT) are discussed. AGT resembles bacteria-mediated protein delivery, as the therapeutical proteins are produced not by host cells but by the bacteria in situ and the expression can be regulated exogenously. Although the procedure of bacterial gene delivery is far from being definitely solved, bactofection remains a promising technique for transfection in human gene therapy.

On the effects of testosterone on brain behavioral functions

Testosterone influences the brain via organizational and activational effects. Numerous relevant studies on rodents and a few on humans focusing on specific behavioral and cognitive parameters have been published. The results are, unfortunately, controversial and puzzling. Dosing, timing, even the application route seem to considerably affect the outcomes. In addition, the methods used for the assessment of psychometric parameters are a bit less than ideal regarding their validity and reproducibility. Metabolism of testosterone contributes to the complexity of its actions. Reduction to dihydrotestosterone by 5-alpha reductase increases the androgen activity; conversion to estradiol by aromatase converts the androgen to estrogen activity. Recently, the non-genomic effects of testosterone on behavior bypassing the nuclear receptors have attracted the interest of researchers. This review tries to summarize the current understanding of the complexity of the effects of testosterone on brain with special focus on their role in the known sex differences.

The anxiolytic effect of testosterone in the rat is mediated via the androgen receptor.

Endogenous and exogenous testosterone affects several behavioural traits as shown in human and animal studies. The effects of testosterone can be mediated via androgen or oestrogen receptors, but also via rapid non-genomic effects. The aim of this study was to evaluate whether a single testosterone injection has effects, mediated via the androgen receptor, on anxiety in intact male rats. We hypothesised that administration of testosterone will have an anxiolytic effect, mediated by the androgen receptor. Intact adult male Wistar rats were divided into groups: control, flutamide, testosterone and testosterone with flutamide. Testosterone and flutamide (as an androgen receptor blocker) were applied once, intramuscularly, at a dose of 5mg/kg. Twenty four hours later, rats underwent the following behavioural tests to analyse anxiety: open field test, elevated plus maze and light-dark box. Testosterone was measured in plasma to confirm elevated levels in groups that received testosterone. The levels of testosterone were 2.5-3 fold higher amongst rats administered with testosterone compared to controls. Flutamide did not affect plasma testosterone concentrations. Testosterone administration had no effect on anxiety in the open field and elevated plus maze. In the light-dark transition task, testosterone increased the time spent in the light part of the maze by 80%, an effect which was blocked by flutamide, and which was in support of our hypothesis. Flutamide-treated rats spent more time in the central square of the open field. Using the light-dark box we have shown that a single injection of testosterone decreases anxiety in adult male rats. This effect of increased testosterone was mediated via the androgen receptor as flutamide blocked the anxiolytic effect of exogenous testosterone. Treatment with flutamide blocked the effects of endogenous testosterone and had anxiolytic effects in the open field, suggesting a non-linear relationship between genomic effects of T and anxiety.

Salivary thiobarbituric acid reacting substances and malondialdehyde - Their relationship to reported smoking and to parodontal status described by the papillary bleeding index

Background. Thiobarbituric reacting substances (TBARS) are markers of lipoperoxidation. The best-known specific TBARS is malondialdehyde (MDA). Results from our previous studies have shown that TBARS can be measured in saliva and are increased in patients with gingivitis. Whether MDA is the main TBARS in saliva from patients with altered parodontal status is unknown. Aim. To observe the relationship between the parodontal status and TBARS, MDA and the number of epithelial cells in saliva. Subjects & Methods. In Study I saliva and plasma samples of 15 patients (8F, 7M) suffering from inflammatory periodontal diseases were gathered and TBARS levels were measured in these samples. In Study II saliva samples from 217 consecutive stomatologic patients were collected and analysed for TBARS spectrofluorometrically, MDA by high-performance liquid chromatography and epithelial cell count by light microscopy. Papillary bleeding index (PBI) was determined in standard stomatologic examination. Results. In Study I results from our previous studies showing no correlation between salivary and plasma TBARS levels were confirmed. This indicates that the local salivary level of TBARS is unlikely to be directly affected by systemic oxidative stress. In Study II higher PBI was associated independently (adjusted for age and sex) tightly with higher TBARS (p < 0.001) and with lower number of epithelial cells in saliva (p < 0.05). Smokers had higher salivary MDA levels (p < 0.003) and lower number of epithelial cells in saliva (p < 0.01). Conclusion. Salivary TBARS are a simple parameter that partially reflects the parodontal status with a potential usefulness in the clinical stomatology. We show herein that salivary MDA is dependent on age and smoking, but there is no correlation between MDA and PBI. Further studies should uncover the main salivary TBARS compound in patients with altered parodontal status and trace the origin of these salivary lipoperoxidation markers.

Variability of thiobarbituric acid reacting substances in saliva

Introduction: Salivary TBARS are a potential marker of oxidative stress in the oral cavity. Previous studies have found increased levels of salivary TBARS in various diseases. The aim of this study was to assess the variability of salivary TBARS in both genders. Subjects & Methods: Saliva samples from thirty-eight healthy volunteers (18F & 20M) were collected every day during 30 day period. TBARS levels were measured spectrophotometrically using a high-throughput 96-well plate method. Time series analysis was performed using standard statistical methods. Results: Repeated measures ANOVA showed a significant variation of salivary TBARS within day and subjects (p < 0.001). The dynamics did not differ between genders. Intraindividual variability was very high in both genders with coefficients of variation of more than 60%. Interindividual variability was higher in men than in women (73% vs. 46%; p < 0.01). Discussion: The relatively high intraindividual variability indicates that the use of salivary TBARS will be limited to research on a population level, although some informative value might be gained by repeated samplings. Factors influencing the biological variability of salivary TBARS should be identified in further studies.

The peroxisome proliferator-activated receptor-α agonist, BAY PP1, attenuates renal fibrosis in rats

Recent studies have shown renoprotective effects of the peroxisome proliferator-activated receptor-α (PPAR-α), but its role in kidney fibrosis is unknown. In order to gain insight into this, we examined the effect of a novel PPAR-α agonist, BAY PP1, in two rat models of renal fibrosis: unilateral ureteral obstruction and the 5/6 nephrectomy. In healthy animals, PPAR-α was expressed in tubular but not in interstitial cells. Upon induction of fibrosis, PPAR-α was significantly downregulated, and treatment with BAY PP1 significantly restored its expression. During ureteral obstruction, treatment with BAY PP1 significantly reduced tubulointerstitial fibrosis, proliferation of interstitial fibroblasts, and TGF-β(1) expression. Treatment with a less potent PPAR-α agonist, fenofibrate, had no effects. Treatment with BAY PP1, initiated in established disease in the 5/6 nephrectomy, halted the decline of renal function and significantly ameliorated renal fibrosis. In vitro, BAY PP1 had no direct effect on renal fibroblasts but reduced collagen, fibronectin, and TGF-β(1) expression in tubular cells. Conditioned media of BAY PP1-treated tubular cells reduced fibroblast proliferation. Thus, renal fibrosis is characterized by a reduction of PPAR-α expression, and treatment with BAY PP1 restores PPAR-α expression and ameliorates renal fibrosis by modulating the cross-talk between tubular cells and fibroblasts. Hence, potent PPAR-α agonists might be useful in the treatment of renal fibrosis.

Salivary markers of oxidative stress in patients with oral premalignant lesions

The aetiology of oral premalignant lesions is unknown. Oxidative stress is associated with inflammation and cancerogenesis. The aim of our study was to compare salivary markers of oxidative and carbonyl stress in patients with oral premalignant lesions and age-matched healthy controls. Unstimulated saliva samples were collected from 16 patients with oral premalignant lesions (leukoplakia, lichen planus, erythroplakia) and 16 age-matched healthy controls. Biochemical analysis included measurement of thiobarbituric acid reacting substances (TBARS), advanced oxidation protein products (AOPP), advanced glycation endproducts (AGEs) and total antioxidant capacity (TAC). Salivary RNA was analyzed using real time PCR. Salivary TBARS and AGEs were significantly higher in patients than in controls. No differences were found in AOPP. TAC and expression of superoxide dismutase were lower in patients than in age-matched controls. Other analyzed transcripts (vascular endothelial growth factor, sialotransferase, neuraminidase) did not differ between patients and the control group. Markers of lipoperoxidation and carbonyl stress were increased in patients with oral premalignant lesions. Decreased antioxidant status potentially due to decreased expression of antioxidant enzymes might be responsible for these findings. Our results might point to the aetiology or pathogenesis of oral premalignant lesions as well as to the mechanism of transition to oral carcinoma.

Endocrine and cognitive effects of short-time soybean consumption in women.

Background: Soy phytoestrogens are known to influence the hormonal status acting as partial estrogen agonists. Soy-derived food supplements are advised for hormone replacement therapy, prevention of atherosclerosis, age-related cognitive decline and even hormone-dependent cancer, although results from clinical studies are controversial. Whether increased soybean intake can affect the endocrine status and cognitive abilities is largely unknown. Aim: To observe the effects of 1 week of increased soybean intake on sex hormone levels and spatial cognitive abilities in women. Subjects and Methods: 16 young healthy female volunteers were asked to eat 900 g of soybeans within 1 week. Salivary testosterone (T), free and total plasma T, salivary and plasma estradiol (E) were measured by radioimmunoassay before and after the study period. Mental rotation (MR) and spatial visualization (SV) psychological tests were done at the days of sampling. Results: Soybean intake increased total plasma T levels (p < 0.02) while decreasing salivary T (p < 0.01) and not altering free plasma T levels. Salivary and plasma E levels were not changed. The results of MR and SV tests were improved after the study period. Conclusion: Short-time increased soybean intake alters the level of total plasma and salivary T and improves spatial cognition in women. Whether this effect is mediated by modulation of estrogen receptors, changes in sex hormone-binding globulin production or changes in activity of steroid-competent enzymes needs further study.

The Effect of Testosterone on the Formation of Brain Structures

It has been confirmed in several studies that testosterone can significantly affect brain development. Following metabolism of this hormone by 5α-reductase to dihydrotestosterone, testosterone may act via androgen receptors, or after conversion by aromatase to estradiol, it may act via estrogen receptors. The parts of the brain which are changed under the influence of sex hormones are known as sexually dimorphic nuclei, especially in the preoptic area of the hypothalamus. Nevertheless, evidence suggests that testosterone also influences the structure of the hippocampus, specifically CA1 and CA3 areas of the hippocampus, as well as the amygdala. These brain areas are designed to convert information from short-term into long-term memory. In this review, we summarize the effects of testosterone on the organization of brain structures with respect to spatial cognitive abilities in small rodents.

Intelligence and salivary testosterone levels in prepubertal children.

BACKGROUND Hormones are one of the regulatory systems influencing brain-cognition interactions and subsequent emotions and behavior in humans and animals. Sex hormones have been found to influence brain structures prenatally, so as to prepare targeted neuronal circuits for activation during and after puberty. Testosterone is believed to affect cognition and thinking in humans as well as between-sex differences in cognitive abilities. AIM The aim of this paper was to investigate associations between testosterone and different levels of intelligence in young prepubertal children of both sexes. METHODS Two hundred and eighty four prepubertal children of both sexes between 6 and 9 years of age provided saliva samples. Of these, 107 were intellectually gifted (IQ above 130), 100 children of average intelligence--randomly chosen from general population (IQ between 70 and 130), and 77 children mentally challenged (IQ less than 70). RESULTS Our results have revealed the differences in salivary testosterone levels in boys grouped according to IQ, intellectually gifted and mentally challenged boys having lower salivary testosterone levels than their peers characterized by average intelligence proposing the common biological characteristic of minority IQ groups on both ends of the Gauss curve. In girls, no differences in salivary testosterone levels were found among IQ groups. CONCLUSIONS Our findings are the first that present the relationship between testosterone and the broad range of general IQ in childhood. The boys of average intelligence had significantly higher testosterone levels than both mentally challenged and intellectually gifted boys, with the latter two groups showing no significant difference between each other. The functional implications of the brain-cognition interactions remain to be fully explored with regard to the internal milieu influencing neural substrate.