Publications by authors named "Dimitrios Tsoukalas"

8 Publications

  • Page 1 of 1

A review of the alleged health hazards of monosodium glutamate.

Compr Rev Food Sci Food Saf 2019 Jul 8;18(4):1111-1134. Epub 2019 May 8.

Faculty of Pharmacy, "Carol Davila" Univ. of Medicine and Pharmacy, Traian Vuia 6, Bucharest, 020956, Romania.

Monosodium glutamate (MSG) is an umami substance widely used as flavor enhancer. Although it is generally recognized as being safe by food safety regulatory agencies, several studies have questioned its long-term safety. The purpose of this review was to survey the available literature on preclinical studies and clinical trials regarding the alleged adverse effects of MSG. Here, we aim to provide a comprehensive overview of the reported possible risks that may potentially arise following chronic exposure. Furthermore, we intend to critically evaluate the relevance of this data for dietary human intake. Preclinical studies have associated MSG administration with cardiotoxicity, hepatotoxicity, neurotoxicity, low-grade inflammation, metabolic disarray and premalignant alterations, along with behavioral changes. Moreover, links between MSG consumption and tumorigenesis, increased oxidative stress and apoptosis in thymocytes, as well as genotoxic effects in lymphocytes have been reported. However, in reviewing the available literature, we detected several methodological flaws, which led us to conclude that these studies have limited relevance for extrapolation to dietary human intakes of MSG risk exposure. Clinical trials have focused mainly on the effects of MSG on food intake and energy expenditure. Besides its well-known impact on food palatability, MSG enhances salivary secretion and interferes with carbohydrate metabolism, while the impact on satiety and post-meal recovery of hunger varied in relation to meal composition. Reports on MSG hypersensitivity, also known as 'Chinese restaurant syndrome', or links of its use to increased pain sensitivity and atopic dermatitis were found to have little supporting evidence. Based on the available literature, we conclude that further clinical and epidemiological studies are needed, with an appropriate design, accounting for both added and naturally occurring dietary MSG. Critical analysis of existing literature, establishes that many of the reported negative health effects of MSG have little relevance for chronic human exposure and are poorly informative as they are based on excessive dosing that does not meet with levels normally consumed in food products.
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http://dx.doi.org/10.1111/1541-4337.12448DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6952072PMC
July 2019

Developing BIOTEL: A Semi-Automated Spreadsheet for Estimating Telomere Length and Biological Age.

Front Genet 2019 19;10:84. Epub 2019 Feb 19.

Laboratory of Toxicology, Medical School, University of Crete, Heraklion, Greece.

Telomere length (TL) is causally related to aging and several age-related diseases. Specifically, the abundance of short telomeres and the rate of telomere shortening are strong determinants of cell homeostasis. Thus, tools for analyzing and manipulating TL data can vastly improve research focused on aging. Aim: In this study, we developed a semi-automated worksheet, BIOTEL, to generate individual and group TL statistics and provide a crude estimation of biological age. Data from the Telomere Length Database Project (TLDP) were implemented to the spreadsheet to produce TL statistics. 150 participants were included, and their age was from 21 to 82 years, and the sex distribution ratio was 52.3%: 47.7% (male: female). Initially, we analyzed the fluorescence intensities of telomeres that were measured on metaphase spread leukocytes using three-dimensional (3D) quantitative-fluorescent hybridization (Q-FISH) procedures (3D DNA FISH) with a (C3TA2)3 peptide nucleic acid (PNA) probe. Raw data of fluorescence intensities, demographic data and medical records from the participants were imported into the worksheet. Basic statistical analyses of TL data were provided through BIOTEL, including TL percentiles, specialized charts for TL distribution including the percentage of critically short telomeres (< 3,000 kilobases), individual telomere profiles, and graphs of biological age vs. chronological age. BIOTEL ver. 2.4 is a functional semi-automated worksheet that calculates a wide range of TL statistics, thus a useful tool with applications in research of telomeres and biological age estimation.
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http://dx.doi.org/10.3389/fgene.2019.00084DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6389611PMC
February 2019

Application of metabolomics part II: Focus on fatty acids and their metabolites in healthy adults.

Int J Mol Med 2019 Jan 14;43(1):233-242. Epub 2018 Nov 14.

Laboratory of Toxicology and Forensic Sciences, Medical School, University of Crete, 71003 Heraklion, Greece.

Fatty acids (FAs) play critical roles in health and disease. The detection of FA imbalances through metabolomics can provide an overview of an individual's health status, particularly as regards chronic inflammatory disorders. In this study, we aimed to establish sensitive reference value ranges for targeted plasma FAs in a well‑defined population of healthy adults. Plasma samples were collected from 159 participants admitted as outpatients. A total of 24 FAs were analyzed using gas chromatography‑mass spectrometry, and physiological values and 95% reference intervals were calculated using an approximate method of analysis. The differences among the age groups for the relative levels of stearic acid (P=0.005), the omega‑6/omega‑3 ratio (P=0.027), the arachidonic acid/eicosapentaenoic acid ratio (P<0.001) and the linoleic acid‑produced dihomo‑gamma‑linolenic acid (P=0.046) were statistically significant. The majority of relative FA levels were higher in males than in females. The levels of myristic acid (P=0.0170) and docosahexaenoic acid (P=0.033) were significantly different between the sexes. The reference values for the FAs examined in this study represent a baseline for further studies examining the reproducibility of this methodology and sensitivities for nutrient deficiency detection and investigating the biochemical background of pathological conditions. The application of these values to clinical practice will allow for the discrimination between health and disease and contribute to early prevention and treatment.
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http://dx.doi.org/10.3892/ijmm.2018.3989DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6257830PMC
January 2019

Stanozolol administration combined with exercise leads to decreased telomerase activity possibly associated with liver aging.

Int J Mol Med 2018 Jul 26;42(1):405-413. Epub 2018 Apr 26.

Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Istanbul University, Istanbul 34116, Turkey.

Anabolic agents are doping substances which are commonly used in sports. Stanozolol, a 17α‑alkylated derivative of testosterone, has a widespread use among athletes and bodybuilders. Several medical and behavioral adverse effects are associated with anabolic androgenic steroids (AAS) abuse, while the liver remains the most well recognized target organ. In the present study, the hepatic effects of stanozolol administration in rats at high doses resembling those used for doping purposes were investigated, in the presence or absence of exercise. Stanozolol and its metabolites, 16‑β‑hydroxystanozolol and 3'‑hydroxystanozolol, were detected in rat livers using liquid chromatography‑mass spectrometry (LC‑MS). Telomerase activity, which is involved in cellular aging and tumorigenesis, was detected by examining telomerase reverse transcriptase (TERT) and phosphatase and tensin homolog (PTEN) expression levels in the livers of stanozolol‑treated rats. Stanozolol induced telomerase activity at the molecular level in the liver tissue of rats and exercise reversed this induction, reflecting possible premature liver tissue aging. PTEN gene expression in the rat livers was practically unaffected either by exercise or by stanozolol administration.
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http://dx.doi.org/10.3892/ijmm.2018.3644DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5979936PMC
July 2018

HPV strain distribution in patients with genital warts in a female population sample.

Oncol Lett 2016 Sep 22;12(3):1779-1782. Epub 2016 Jul 22.

Department of Forensic Sciences and Toxicology, Medical School, University of Crete, Heraklion 71003, Greece.

The incidence of human papillomavirus (HPV) in the human cancer domain is still a subject of intensive study. In this study, we examined cervical swab samples from 713 females with genital warts, and tested the samples for high- and low-risk genital HPV. HPV genotyping was assessed using a Genotyping test that detects HPV by the amplification of target DNA using polymerase chain reaction and nucleic acid hybridization. In total, we detected 37 anogenital HPV DNA genotypes [6, 11, 16, 18, 26, 31, 33, 35, 39, 40, 42, 45, 51, 52, 53, 54, 55, 56, 58, 59, 61, 62, 64, 66, 67, 68, 69, 70, 71, 72, 73 (MM9), 81, 82 (MM4), 83 (MM7), 84 (MM8), IS39 and CP6108] and investigated the incidence of these genotypes in the patients with genital warts. We found differences in the distribution of high-/low-risk strains and the incidence of high-risk strains was found to occur mainly in females under 35 years of age. The data from our study suggest that a detailed oral, rectal and genital identification of high-risk strains should be performed to visualize the entire pattern of possible triggers of carcinogenesis.
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http://dx.doi.org/10.3892/ol.2016.4903DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4998207PMC
September 2016

Telomerase activity in pregnancy complications (Review).

Mol Med Rep 2016 Jul 9;14(1):16-21. Epub 2016 May 9.

Center of Toxicology Science and Research, University of Crete, Heraklion 71003, Greece.

Telomeres are specific DNA regions positioned at the ends of chromosomes and composed of functional non-coding repeats. Upon cell division, the telomeres decrease in length by a preordained amount. When the telomeres become critically short, cells lose the ability to divide and enter a specific functioning mode designated as 'cellular senescence'. However, human tissues express an enzyme that deters the shrinking of the telomeres, the telomerase. Due to its ability to maintain telomere length, the telomerase slows down and possibly suspends the aging of the cells. In regard to this, solid evidence demonstrates that female human fertility decreases with increased maternal age and that various adverse factors, including alterations in telomerase activity, can contribute to age-associated infertility in women. The fact that telomerase activity is regulated in a time- and location-dependent manner in both embryo and placental tissues, highlights it potential importance to the successful completion of pregnancy. Since maternal age is a crucial determining factor for the success of in vitro and in vivo fertilization, numerous studies have focused on telomerase activity and its correlation with mammalian fertilization, as well as the following cleavage and pre-implantation developmental processes. Associations between telomerase activity and pregnancy complications have been previously observed. Our aim in this review was to summarize and critically discuss evidence correlating telomerase activity with pregnancy complications.
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http://dx.doi.org/10.3892/mmr.2016.5231DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4918539PMC
July 2016

Immediate flapless implant placement and provisionalization: challenge for optimum esthetics and function: a case report.

J Oral Implantol 2008 ;34(1):52-8

Department of Dentoalveolar/Implant Surgery and Radiology, Aristotle University of Thessaloniki, School of Dentistry, Greece.

This report presents a case of tooth extraction and immediate flapless implant placement followed by fabrication of transitional restoration. The tooth was extracted atraumatically with the use of a periotome followed by careful debridement. An osteotomy was performed up to 5 mm beyond the base of the socket and depth using the alveolar crest as a landmark, following a slightly palatal direction. The implant shoulder was inserted 3 mm below the cementoenamel junction of the adjacent tooth. The interproximal distance from the neighboring teeth was 3 mm. No membranes and/or grafts were used. Initial impressions were taken immediately after implant placement; 6 hours later a well-polished and slightly overcontoured (at the distal-mesial aspect) acrylic crown was fixed onto the implant. There were no contacts in the centric and lateral positions. Five months later, the occlusion was modified allowing slight contacts in the centric position for an additional 2 months. The final prosthetic restoration was placed 2 months later (7 months after surgery), consisting of a full ceramic crown cemented on a customized metal ceramic UCLA abutment. The technique maintained the integrity of hard and soft tissues and created a very favorable esthetic result. It also provided the patient with a transitional fixed restoration and reduced the time required for therapy completion. Because research on this field is limited, further investigation is required to support the results of this report, despite the promising clinical outcome.
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http://dx.doi.org/10.1563/1548-1336(2008)34[52:IFIPAP]2.0.CO;2DOI Listing
May 2008

The role of temperature in the action of mepivacaine.

Anesth Prog 2006 ;53(3):91-4

Department of Oral Surgery, Implantology and Roentgenology, Aristotle University of Thessaloniki, Greece.

The role of temperature in the action of local anesthetics was studied in 20 healthy young volunteers with plain 3% mepivacaine injected periapically twice in their maxillary first premolar, the first time with the solution at a temperature of 20 degrees C and the second time at 4 degrees C. The pulpal response was measured with a pulp tester every minute. The onset of pulp anesthesia was found to be of no statistical difference between 20 degrees C and 4 degrees C. On the other hand, mepivacaine at a temperature of 4 degrees C was found to have a statistically significant longer duration of action. Our conclusion is that the drop in temperature of mepivacaine from 20 degrees C to 4 degrees C provides a longer duration of pulpal anesthesia.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1693662PMC
http://dx.doi.org/10.2344/0003-3006(2006)53[91:TROTIT]2.0.CO;2DOI Listing
January 2007