History and Genetics of Retinoblastoma

The history of retinoblastoma (RB) goes back to 1597 when Pieter Pawius of Amsterdam described a tumor that resembled retinoblastoma. “Fungus haematodes” was the first term used to describe retinoblastoma. Later, the American Ophthalmological Society approved the term retinoblastoma in 1926. The retinoblastoma protein is encoded by the RB1 gene located at 13q14. The functioning model of the tumor suppressor genes was first proposed by Alfred Knudson in the 1970s who precisely explained the hereditary mechanism of retinoblastoma. If both alleles of this gene are mutated, the protein is inactivated and this results in the development of retinoblastoma. One mutation can be either germline or somatic and the second one is always somatic. Differentiation between sporadic and germline retinoblastoma variants requires the identification of the RB1 germline status of the patient. This identification is important for assessing the risk of additional tumors in the same eye, the other eye, and the risk of secondary tumors. Thus, genetic testing is an important component of the management of all children diagnosed with retinoblastoma. In this chapter, we will go over the history, genetics, and counseling for patients with retinoblastoma

Expression of Glucose Transporters 1 and 3 in the Placenta of Pregnant Women with Gestational Diabetes Mellitus

Background: The annual prevalence of gestational diabetes mellitus—characterized by an increase in blood glucose in pregnant women—has been increasing worldwide. The goal of this study was to evaluate the expression of glucose transporter 1 (GLUT1) and glucose transporter 3 (GLUT3) in the placenta of women with gestational diabetes mellitus. Methods: Sixty-five placentas from women admitted to the King Saud University Medical City, Riyadh, Saudi Arabia, were analyzed; 34 and 31 placentas were from healthy pregnant women and women with gestational diabetes, respectively. The expressions of GLUT1 and GLUT3 were assessed using RT-PCR, Western blotting, and immunohistochemical methods. The degree of apoptosis in the placental villi was estimated via a TUNEL assay. Results: The results of the protein expression assays and immunohistochemical staining showed that the levels of GLUT1 and GLUT3 were significantly higher in the placentas of pregnant women with gestational diabetes than those in the placentas of healthy pregnant women. In addition, the findings showed an increase in apoptosis in the placenta of pregnant women with gestational diabetes compared to that in the placenta of healthy pregnant women. However, the results of gene expression assays showed no significant difference between the two groups. Conclusions: Based on these results, we conclude that gestational diabetes mellitus leads to an increased incidence of apoptosis in the placental villi and alters the level of GLUT1 and GLUT3 protein expressions in the placenta of women with gestational diabetes. Understanding the conditions in which the fetus develops in the womb of a pregnant woman with gestational diabetes may help researchers understand the underlying causes of the development of chronic diseases later in life

Involvement of Autophagy and Oxidative Stress-Mediated DNA Hypomethylation in Transgenerational Nephrotoxicity Induced in Rats by the Mycotoxin Fumonisin B1

Fumonisin B1 (FB1), a mycotoxin produced by Fusarium verticillioides, is one of the most common pollutants in natural foods and agricultural crops. It can cause chronic and severe health issues in humans and animals. The aim of this study was to evaluate the transgenerational effects of FB1 exposure on the structure and function of the kidneys in offspring. Virgin female Wistar rats were randomly divided into three groups: group one (control) received sterile water, and groups two and three were intragastrically administered low (20 mg/kg) and high (50 mg/kg) doses of FB1, respectively, from day 6 of pregnancy until delivery. Our results showed that exposure to either dose of FB1 caused histopathological changes, such as atrophy, hypercellularity, hemorrhage, calcification, and a decrease in the glomerular diameter, in both the first and second generations. The levels of the antioxidant markers glutathione, glutathione S-transferase, and catalase significantly decreased, while malondialdehyde levels increased. Moreover, autophagy was induced, as immunofluorescence analysis revealed that LC-3 protein expression was significantly increased in both generations after exposure to either dose of FB1. However, a significant decrease in methyltransferase (DNMT3) protein expression was observed in the first generation in both treatment groups (20 mg/kg and 50 mg/kg), indicating a decrease in DNA methylation as a result of early-life exposure to FB1. Interestingly, global hypomethylation was also observed in the second generation in both treatment groups despite the fact that the mothers of these rats were not exposed to FB1. Thus, early-life exposure to FB1 induced nephrotoxicity in offspring of the first and second generations. The mechanisms of action underlying this transgenerational effect may include oxidative stress, autophagy, and DNA hypomethylation

Physiological Responses of the Bivalves <i>Mytilus galloprovincialis</i> and <i>Ruditapes decussatus</i> Following Exposure to Phenanthrene: Toxicokinetics, Dynamics and Biomarkers Study

The aim of the current study was to assess the multifaceted effects of the polycylic aromatic hydrocarbon phenanthrene, mainly used in the colouring, explosive, and pharmaceutical industries, on the physiology of two bivalve species with economic value as seafood, namely, the Mediterranean mussel Mytilus galloprovincyalis and the European clam Ruditapes decussatus. The current study assessed how the phenanthrene affected several biomarkers and biometric endpoints in both bivalves, based on an in vivo experiment in silico approach. The bivalves were exposed during four time slots (i.e., 7, 15, 21, and 28 days) to two concentrations of phenanthrene in water (50 µg/L and 100 µg/L). For the clam R. decussatus, an additional contamination of sediment was applied due their typical benthic lifestyle (50 µg/kg and 100 µg/kg). The phenanthrene significantly reduced the ability of bivalves to tolerate desiccation and their Median Lethal Time, and also inhibited the activity of the enzyme acetylcholinesterase in a time-dependent manner. The activity of catalase indicated that bivalves also experienced oxidative stress during the first 21 days of the experiment. The significant decline in catalase activity observed during the last week of the experiment for the mussel M. galloprovincyalis supported a depletion of enzymes caused by the phenanthrene. The phenanthrene has also toxicokinetic and toxicodynamic properties, as assessed by the in silico approach. Overall, the results obtained suggest that the bivalves Ruditapes decussatus and M. galloprovincyalis can be used as a sentinel species in monitoring studies to assess the environmental impact of phenanthene in marine ecosystems. The significance of our findings is based on the fact that in ecotoxicology, little is known about the chronic effects, the simultaneous use of multiple species as bioindicators, and the interactions molecular modelling

Hyperhalophilic Diatom Extract Protects against Lead-Induced Oxidative Stress in Rats and Human HepG2 and HEK293 Cells

This work investigated the protective effects of microalga Halamphora sp. extract (HExt), a nutraceutical and pharmacological natural product, on human lead-intoxicated liver and kidney cells in vitro and in vivo in Wistar rats. The human hepatocellular carcinoma cell line HepG2 and the human embryonic kidney cell line HEK293 were used for the in vitro study. The analysis of the fatty acid methyl esters in the extract was performed via GC/MS. The cells were pretreated with HExt at 100 µg mL−1, followed by treatment with different concentrations of lead acetate, ranging from 25 to 200 µM for 24 h. The cultures were incubated (5% CO, 37 °C) for 24 h. Four groups, each containing six rats, were used for the in vivo experiment. The rats were exposed to subchronic treatment with a low dose of lead acetate (5 mg kg−1 b.w. per day). Pretreating HepG2 and HEK293 cells with the extract (100 µg mL−1) significantly (p < 0.05) protected against the cytotoxicity induced by lead exposure. For the in vivo experiment, the biochemical parameters in serum—namely, the level of malondialdehyde (MDA), and the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)—were measured in the organ homogenate supernatants. HExt was found to be rich in fatty acids, mainly palmitic and palmitoleic acids (29.464% and 42.066%, respectively). In both the in vitro and in vivo experiments, cotreatment with HExt protected the liver and kidney cell structures and significantly preserved the normal antioxidant and biochemical parameters in rats. This study discovered the possible protective effect of HExt, which could be beneficial for Pb-intoxicated cells