The dose response principle from philosophy to modern toxicology: The impact of ancient philosophy and medicine in modern toxicology science.

Since ancient times the concept of dose response, from a toxicological perspective, has been a matter of concern. Already by the 8th century BC and over the years, many enlightened people have attempted to interpret this phenomenon, observing and coming across its results and practical implementation through exposure to chemical substances, either from natural or synthetic sources. Nowadays, the environmental exposure of human populations to chemicals in terms of quantity and quality might differ. Nevertheless, dose response still remains an issue joining hands with scientific and technological progress. The aim of the present review is not only to briefly recount the history of the dose response concept, from ancient time theories to novel approaches, but also to draw the outline of challenges and requirements toxicology science needs to fulfill.

Common mental disorders and association with telomere length.

Telomeres are repeated 5'-TTAGGG-3' sequences at the end of chromosomes, which maintain genomic stability. Their length is related to a number of diseases that affect humans. Apart from cancer, cardiovascular diseases, diabetes and other, telomere length has been associated with chronic diseases. Chronic mental illness includes various types of mental disorders with the most common being depression, schizophrenia and stress-anxiety. The aim of this review is to summarize the current state of knowledge on the role of telomeres in these disorders and to compare telomere length variations in patients receiving medication and patients not taking treatment. Most studies report reduced telomere length in patients suffering from mental disorders, compared to the general population. Since the factors that can affect telomere length are various, more experiments and investigations are required to understand the general impact of different factors on telomere length.

Seasonal trends in the prevalence of hypospadias: Aetiological implications.

The aim of the present study was to examine the seasonality of hypospadias in Greece in an attempt to elucidate the aetiology. All boys born between 1991-1998, who underwent hypospadias repair at 'Aghia Sophia' Children's Hospital, Athens (n=542) were analysed. All Greek live-born males during the same period (population at risk; m=421,175) served as the controls. Seasonality by month of birth was evaluated with specific statistical tools. Meteorological parameters were also analysed. All tests yielded significant results, suggesting a simple harmonic prevalence pattern (highest/lowest: autumn, peak in October/spring, trough in April). Therefore, the first trimester of hypospadiac gestations coincides more frequently with winter. Meteorological parameters varied seasonally (maximal sunlight; air temperature in summer/minimal in winter, maximal rainfall in winter/minimal in summer) and were strongly associated pairwise. Hypospadiac birth prevalence follows a simple harmonic seasonal pattern and is associated with that of cryptorchidism in Greece. The coincidence of the first or third trimester of a potentially genetically influenced gestation with winter could lead to the phenotypic expression of hypospadias or cryptorchidism, respectively. The potential role of a cyclic-varied androgen-production stimulator, such as human chorionic gonadotrophin may be speculated. The seasonality of a common environmental factor acting directly/indirectly may contribute to these patterns, and possibly to the common pathogenesis of these congenital malformations.

miRNAs and their role in the correlation between schizophrenia and cancer (Review).

Schizophrenia (SZ) and cancer (Ca) have a broad spectrum of clinical phenotypes and a complex biological background, implicating a large number of genetic and epigenetic factors. SZ is a chronic neurodevelopmental disorder signified by an increase in the expression of apoptotic molecular signals, whereas Ca is conversely characterized by an increase in appropriate molecular signaling that stimulates uncontrolled cell proliferation. The rather low risk of developing Ca in patients suffering from SZ is a hypothesis that is still under debate. Recent evidence has indicated that microRNAs (miRNAs or miRs), a large group of small non­coding oligonoucleotides, may play a significant role in the development of Ca and major psychiatric disorders, such as SZ, bipolar disorder, autism spectrum disorders, suicidality and depression, through their interference with the expression of multiple genes. For instance, the possible role of let­7, miR­98 and miR­183 as biomarkers for Ca and SZ was investigated in our previous research studies. Therefore, further investigations on the expression profiles of these regulatory, small RNA molecules and the molecular pathways through which they exert their control may provide a plausible explanation as to whether there is a correlation between psychiatric disorders and low risk of developing Ca.

Endometriosis and breast cancer: A survey of the epidemiological studies.

Endometriosis is a chronic gynecological disease with a wide spectrum of clinical manifestations that affects approximately 10% of women of reproductive age. Recent reviews have demonstrated the connection between endometriosis and breast cancer, which represents the most frequently diagnosed female cancer and the most common cause of cancer-related mortality among women worldwide. The aim of this study was to conduct a survey of available published epidemiological studies indicating the association between endometriosis and breast cancer, and simultaneously to categorize the results based on the strength of the association, with the intention of the critical evaluation of the existing data. We performed a rigorous search of the PubMed/Medline database, using the key words 'endometriosis' and 'breast cancer' for all studies published in the English language until September 2015. We found 4 retrospective cohort studies, 4 case-control studies and 3 case-cohort studies that demonstrated a notable risk for developing breast cancer among women with endometriosis. By contrast, we also found 5 case-control studies, 1 prospective cohort study, 1 case-cohort study and 1 cross-sectional study that demonstrated a negative association between endometriosis and breast cancer. In conclusion, as regards the clarification of a 'robust' or 'weak' association between endometriosis and breast cancer, no definite conclusions could be drawn, due to the limited number of studies and the limitations of each of these studies. New well-designed, prospective cohort or randomized control trials with long-term follow-up are warranted in order to provide evidence-based clinical recommendations for proper counseling, screening and treatment strategies for patients with endometriosis, and hence to improve public health.

Role of the angiopoietin/Tie system in pregnancy (Review).

Angiopoietin-1 and -2 are endogenous ligands for the vascular endothelium-specific receptor tyrosine kinase Tie-2. The angiopoietin/Tie system plays a critical role in the regulation of endothelial cell survival and vascular maturation and stability. Apart from its well-established role in vascular morphogenesis, emerging data support the involvement of angiopoietins in inflammation and various malignancies. Previous studies have underlined the significance of several angiogenic factors in normal placental development. In addition, angiogenic imbalance is observed in pregnancy complications related to impaired placentation, such as preeclampsia (PE) and intrauterine growth restriction (IUGR). However, there is only limited information available on the role of the angiopoietin/Tie system in the establishment of a competent feto-maternal vascular system. In this review, we present the current knowledge regarding the role of angiopoietins in normal pregnancy and pregnancy complications.

Placental mRNA expression of angiopoietins (Ang)-1, Ang-2 and their receptor Tie-2 is altered in pregnancies complicated by preeclampsia.

OBJECTIVE: To investigate the placental expression of angiopoietin (Ang)-1, Ang-2 and their receptor, Tie-2, in preeclampsia (PE) with or without intrauterine growth restriction (IUGR). METHODS: Case-control study including placentas from 28 PE pregnancies, 30 PE-IUGR pregnancies and 40 controls. The expression status of the genes was evaluated by quantitative real-time PCR. RESULTS: In both PE and PE-IUGR groups, compared to the control group, there was significantly higher expression of Ang-2 (p < 0.001) and Tie-2 (p = 0.008) and lower expression of Ang-1 (p = 0.001). The magnitude of the difference was similar for Ang-1 for both groups, whereas the magnitude of the differences was higher for Ang-2 and Tie-2 in PE-IUGR group compared to controls. Ang-2 and Tie-2 were correlated in both PE (r = 0.8602, p < 0.001) and PE-IUGR (r = 0.6342, p < 0.001) groups. In PE-IUGR group, Ang-1 was associated to Ang-2 (r = 0.3458, p = 0.0452) and Tie-2 (r = 0.4448, p = 0.0084). Log10Ang-1 but not Ang-2 was gestational age dependent (R2 = 0.40, p < 0.001). After conversion in Multiples of the Median (MoM) log10 MoM Ang-1 was reduced in the PE group (mean = -0.8181, p < 0.001) and the PE-IUGR group (mean = -1.2583, p < 0.001) compared to control group (mean = -0.0924). DISCUSSION: We have demonstrated increased placental expression of Ang-2 and Tie-2 along with lower expression levels of Ang-1 in pregnancies with PE and PE-IUGR. CONCLUSION: The angiopoietin axis seems to be disrupted in PE pregnancies. Whether the results of this study represent the angiogenic imbalance observed in PE pregnancies or they are part of the pathophysiology of this condition has to be further investigated.

Differential telomerase expression in idiopathic pulmonary fibrosis and non-small cell lung cancer.

Telomerase is a reverse transcriptase ribonucleo-protein (h-TERT) that synthesizes telomeric repeats using its RNA component (h-TERC) as a template. Telomerase dysfunction has been associated with both fibrogenesis and carcinogenesis. In this study, we aimed to evaluate the telomerase mRNA expression levels of both subunits (h-TERT and h-TERC) in lung tissue and bronchoalveolar lavage fluid (BALF) from patients with idiopathic pulmonary fibrosis (IPF) and non-small cell lung cancer (NSCLC), since there are indications of common pathogenetic pathways in these diseases. We prospectively examined lung tissue samples from 29 patients with IPF, 10 patients with NSCLC and 21 controls. Furthermore, we examined BALF samples from 31 patients with NSCLC, 23 patients with IPF and 12 control subjects. The mRNA expression for both h-TERT and h-TERC was measured by real-time RT-PCR. In the lung tissue samples, both h-TERT and h-TERC mRNA expression levels varied among the 3 groups (p=0.036 and p=0.002, respectively). h-TERT mRNA levels in the patients with IPF were lower compared with those in the controls (p=0.009) and patients with NSCLC (p=0.004). h-TERC mRNA levels in the patients with IPF were lower compared with those in the controls (p=0.0005) and patients with NSCLC (p=0.0004). In the BALF samples, h-TERT mRNA expression levels varied among the groups (p=0.012). More specifically, h-TERT mRNA levels in the patients with IPF were higher compared with those in the controls (p=0.03) and patients with NSCLC (p=0.007). The attenuation of telomerase gene expression in IPF in comparison to lung cancer suggests a differential role of this regulatory gene in fibrogenesis and carcinogenesis. Further functional studies are required in order to further elucidate the role of telomerase in these devastating diseases.

The presence of Merkel cell polyomavirus is associated with deregulated expression of BRAF and Bcl-2 genes in non-small cell lung cancer.

Polyomaviruses such as BK virus (BKV), JC virus (JCV) and Merkel cell polyomavirus (MCPyV) are typically nononcogenic, although they have been detected in a variety of human neoplasms. The aim of our study was to determine the frequency of the most common polyomaviruses MCPyV, BKV and JCV as well as the gene expression profile of genes involved in oncogenesis including K-ras, BRAF, RKIP, Bax, Bcl-2, p53 and RB1 in a cohort of non-small cell lung cancer (NSCLC) patients. Real-time and nested polymerase chain reaction (PCR) were used to assess the presence of polyomaviruses DNA in tissue biopsies from 110 patients with primary NSCLC and 14 tissue specimens from macroscopically healthy sites of their lung. Real-time PCR was also used to determine the mRNA expression of K-ras, BRAF, RKIP, Bax, Bcl-2, p53 and RB1 in selected samples. Results showed that ten NSCLC specimens were positive for the presence of MCPyV DNA (10/110, 9.1%), whereas no control sample was tested positive for the virus. The MCPyV-positive samples were predominantly obtained from male smokers (9/10). BKV and JCV DNA were not detected either in lung tissues biopsies or the control specimens. Interestingly, gene expression analysis revealed increased mRNA and protein expression of BRAF gene in association with BRAF phosphorylation in the MCPyV-positive samples, whereas Bcl-2 gene expression was downregulated in the same type of samples. The detected MCPyV prevalence in NSCLC in combination with the deregulated expression of BRAF and Bcl-2 genes suggests that these events are likely to contribute to the pathogenesis of NSCLC.

Vaccination against human papillomavirus in childhood: the next rubella analogue?

Direct comparisons between different vaccination programmes can reveal new targets and solve challenges that have been faced and managed in the past during similar health interventions. In the rubella vaccination programme both boys and girls were included in order to ensure that women of childbearing age are effectively protected. For human papillomavirus (HPV) vaccination, at the moment only girls have been included into the scheme. The aspect of vaccinating both boys and girls against HPV, similarly to the rubella paradigm, would interrupt "high-risk" HPVs transmission from males to females and vice versa ensuring further elimination of HPV. The new generation of HPV vaccines is expected to cost less and this will contribute to the possible introduction of HPV vaccine in both males and females.

Prospective study of human norovirus infection in children with acute gastroenteritis in Greece.

AIM: Noroviruses are considered as a major cause of acute gastroenteritis in childhood worldwide. This prospective study was undertaken to investigate the frequency and clinical features of norovirus infections in children aged less than 5 years with acute gastroenteritis in Greece. METHODS: Routine stool samples were obtained from 227 children, 119 boys and 108 girls, with acute gastroenteritis, who attended a tertiary paediatric hospital in Athens during the period November 2008 - October 2009. All specimens were tested for the presence of norovirus, rotavirus and adenovirus antigens using validated enzyme-linked immunoassays. RESULTS: Norovirus was detected in 8 (7.9%) out of 101 children during the period November 2008 to April 2009, while the respective rate during the period May 2009 to October 2009 was 1/126 (0.8%). In the total sample, rotavirus was detected in 56 (24.7%) children and adenovirus in 5 (2.2%) children. Three (1.3%) samples grew Campylobacter jejuni, while 6 (2.6%) samples grew Salmonella. In all cases, norovirus was detected as a unique viral pathogen. Among norovirus-positive children, who required hospitalization, the median duration of intravenous fluid administration was 3.5 days. The median duration of hospitalization was 4 days (range 3 days to 5 days) and did not differ from the duration of hospitalization of rotavirus-positive children. CONCLUSION: Our results suggest norovirus as the second most common cause of community-acquired acute gastroenteritis in children in Greece, following rotavirus. We highlight the need to implement norovirus detection assays for the clinical diagnosis and the prevention of viral gastroenteritis in paediatric departments.

Human papillomavirus in the oral cavity of children and mode of delivery: a retrospective study.

Our study aimed to examine the relationship between the presence of human papillomavirus (HPV) in the oral cavity of children and their mode of delivery. We investigated the presence of HPV infection in oral biopsies from 190 children (mean age: 7 years, range: 2-14 years) using the polymerase chain reaction (PCR) technique. Sixteen of 190 children (8.4%) were HPV-positive, with no significant difference between those delivered vaginally and by Caesarean section (C-section). The majority of the HPV-positive children were infected with type 16, whereas in the younger age group HPV type 11 was detected more frequently in children delivered by normal vaginal delivery (NVD) than by C-section. Our findings demonstrate the presence of HPV in the oral cavity of children delivered by both C-section as well as NVD. Further research on the possible modes of transmission of oral HPV infection will enable us to understand the natural history of HPV infection in childhood.

George N. Papanicolaou (1883-1962): Fifty years after the death of a great doctor, scientist and humanitarian.

Fifty years have passed since the death of Dr George Nicholas Papanicolaou, who was born in Kyme at the island of Euboea in Greece in 1883 and became known for his innovative revolutionary invention of the Pap smear test performed at the Cornell University Medical College in the USA. To date, even after the introduction of HPV vaccination into the clinical practice, Dr George Papanicolaou's method remains an essential component of the prevention strategy against cancer and has resulted in a 70% decrease in cervical cancer mortality over the last 60 years. This article, which presents briefly his biography, is dedicated to him on the occasion of the 50th anniversary of his death.

Expression profile of Rho kinases in urinary bladder cancer.

PURPOSE: To investigate the expression of RhoA, RhoB, RhoC, Rac1 and Cdc42 kinases in urothelial cell carcinoma (UCC) of the urinary bladder and determine the expression profile of 107 Rho-associated genes, including GTPases, GDIs, GAPs and GEFs. METHODS: Rho expression was investigated using microarrays, qPCR and Western blotting in 77 UCC specimens with paired normal urothelium. Computational analysis was also performed on Gene Expression Omnibus datasets. Further microarray analysis was carried out for the expression profiling of the Rho-associated genes. RESULTS: RhoB mRNA and protein levels were significantly lower in UCC, suggesting a tumour-suppressor role. On the contrary, mRNA of RhoC and protein levels of RhoA, RhoC and Cdc42, respectively, were significantly higher in UCC vs. normal tissue. High Cdc42 mRNA levels correlated with worse overall survival (p=0.027), whereas high RhoB mRNA levels correlated both with better overall (p=0.0258) and cancer-specific (p=0.0272) survival. Computational analysis verified the expression profile of Rho kinases among superficial UCCs, muscle-invasive UCCs and normal tissues. CONCLUSION: The majority of the Rho-related genes showed over-expression in UCC vs. normal tissue. Alterations in RhoA, RhoB, RhoC, Rac1 and Cdc42 expression play a significant role in the genesis and progression of UCC of the urinary bladder.

Herpes virus infection can cause intervertebral disc degeneration: a causal relationship?

It has been proposed that intervertebral disc degeneration might be caused by low-grade infection. The purpose of the present study was to assess the incidence of herpes viruses in intervertebral disc specimens from patients with lumbar disc herniation. A polymerase chain reaction based assay was applied to screen for the DNA of eight different herpes viruses in 16 patients and two controls. DNA of at least one herpes virus was detected in 13 specimens (81.25%). Herpes Simplex Virus type-1 (HSV-1) was the most frequently detected virus (56.25%), followed by Cytomegalovirus (CMV) (37.5%). In two patients, co-infection by both HSV-1 and CMV was detected. All samples, including the control specimens, were negative for Herpes Simplex Virus type-2, Varicella Zoster Virus, Epstein Barr Virus, Human Herpes Viruses 6, 7 and 8. The absence of an acute infection was confirmed both at the serological and mRNA level. To our knowledge this is the first unequivocal evidence of the presence of herpes virus DNA in intervertebral disc specimens of patients with lumbar disc herniation suggesting the potential role of herpes viruses as a contributing factor to the pathogenesis of degenerative disc disease.

mRNA expression of G(1)-phase cell cycle regulatory molecules in bladder cancer.

PURPOSE: Cell cycle regulation, which is important for normal cellular proliferation, is controlled by a complex network of intracellular proteins, with cyclins, cyclin-dependent kinases (CDKs) and cyclin-dependent kinase inhibitors (CD-KIs) playing a central role. This equilibrium is interrupted in cancer cells, resulting in uncontrolled cellular proliferation. METHODS: In the present study we examined, by means of semi-quantitative RT-PCR, the expression of G(1)-phase cell cycle regulators MDM2, E2F1, Cyclin D1 (CCND1), CDK4, p19(INK4D), p21(WAF1/CIP1) and p27(KIP1) in a series of 32 bladder cancer specimens paired with adjacent normal tissues. RESULTS: Cyclin D1 was overexpressed in 10/32 (31.2%) and downregulated in 8/32 (25.0%) bladder cancer specimens. Additionally, p21 was overexpressed in 9/32 (28.1%) and downregulated in 10/32 (31.3%) cancer samples. On the contrary, MDM2, E2F1, CDK4, p19 and p27 expression was normal in the majority of malignant specimens. Further statistical analysis revealed significant associations between increased p21 levels and bladder cancer patients with no exposure to chemicals (p=0.048), as well as with patients with no artificial sweetener intake (p=0.012), and between increased Cyclin D1 levels and study subjects with no artificial sweetener intake (p=0.012). CONCLUSION: Based on these results, we conclude that Cyclin D1 and p21 mRNA deregulation seems to be an important event in bladder carcinogenesis. However, further studies are needed, in order to determine whether these two cell cycle regulators can be used as markers for the early detection of bladder cancer and to monitor its progression and recurrence.

Use of loop-mediated isothermal amplification of DNA for the rapid detection of Mycobacterium tuberculosis in clinical specimens.

Loop-mediated isothermal amplification (LAMP) is a recently developed molecular method that has been successfully implemented in the detection of Mycobacterium tuberculosis in clinical specimens. LAMP has several advantages, such as rapidity, high sensitivity, ease of application and cost-effectiveness. As a result, it is anticipated that its use for the detection of M. tuberculosis is likely to become widespread, especially in low-resource countries. The present review aimed to present this method and all of the available information on its implementation in the detection of M. tuberculosis in clinical specimens.

Hypomethylation along with increased H19 expression in placentas from pregnancies complicated with fetal growth restriction.

The expression of imprinted genes is regulated by epigenetic modifications, such as DNA methylation. Many imprinted genes are expressed in the placenta and affect nutrient transfer capacity of the placental exchange barrier. The H19 gene is abundantly expressed by the human placenta and is implicated in the pathogenesis of congenital growth disorders such as Beckwith-Wiedemann (BWS) and Silver-Russell (SRS) syndromes. The aim of this study was to investigate the role of DNA methylation on H19 transcription and imprinting, in the pathophysiology of fetal growth restriction (FGR). Thirty one and 17 placentas from FGR-complicated and normal pregnancies were collected, respectively. We studied gene transcription, genotyping and methylation analysis of the AluI H19 on exon 5 polymorphism. Placental expression levels of H19 were significantly increased in the FGR group. The H19 mRNA levels were similar between normal placental samples that demonstrated loss and maintenance of imprinting. Placentas from growth-restricted pregnancies had lower methylation levels compared to normals, in the H19 promoter region. We have demonstrated an increased H19 transcription in the FGR group of placentas. The hypomethylation of the H19 promoters is compatible with the aberrant expression. The association of these two findings is reported for the first time in placental tissues, however, its significance remains unknown. Whether the results of this study represent an adaptation of the placenta to hypoperfusion, or they are part of FGR pathophysiology has to be further investigated.

Resistance status and evolution trends of Klebsiella pneumoniae isolates in a university hospital in Greece: ineffectiveness of carbapenems and increasing resistance to colistin.

BACKGROUND: Due to its increased non-susceptibility rates, Klebsiella pneumoniae has emerged as one of the most problematic pathogens. METHODS: The level of resistance to 25 antimicrobials of K. pneumoniae isolates from a teaching hospital in Greece and the evolution trends during 2 decades were examined. RESULTS: A statistically significant increase in non-susceptibility rates was found for almost all antimicrobials examined. During 2008, the isolates presented non-susceptibility rates to aminoglycosides >50% and to quinolones >60%. Nowadays, 1 out of 10 isolates is non-susceptible to colistin. Moreover, the isolates non-susceptible to imipenem were almost doubled between 2007 (29%) and 2008 (50%). Among the imipenem-resistant isolates, 1 out of 4 was also resistant to colistin. CONCLUSION: The effectiveness of carbapenems has been compromised and the increase in resistance to colistin is rapid and steep.

Reduced placental prolyl hydroxylase 3 mRNA expression in pregnancies affected by fetal growth restriction.

OBJECTIVE: To investigate the role of the hypoxia-inducible factor (HIF) pathway in fetal growth restriction (FGR). DESIGN: A case-control study. SETTING: Research laboratory and gynaecology clinic. SAMPLE: Twenty placentas from normal pregnancies and 20 from FGR pregnancies. METHODS: RNA extraction, cDNA synthesis, quantitative real-time polymerase chain reaction (qRT-PCR) assay, statistical analysis. MAIN OUTCOME MEASURES: mRNA expression of HIF-1α, HIF-2α and HIF-ß (ARNT), along with prolyl hydroxylase domain 3 (PHD3), which leads to proteasomal degradation of HIF-α subunits. RESULTS: No statistically significant differences in the transcription levels of ARNT and HIF-2α were found between FGR and normal placentas. By contrast, PHD3 and HIF-1α mRNA were downregulated in FGR placentas. PHD3 mRNA expression was associated with gestational age at delivery (P = 0.008), birthweight centile (P = 0.029) and abnormal umbilical artery (UA) Doppler measurements (P = 0.034). CONCLUSIONS: As PHD3 regulates the HIF-mediated hypoxic response in FGR, we deduce that fetal adaptation to hypoxia ranges from impaired to adequate, as observed by the gradient of PHD3 downregulation in relation to the severity of FGR.