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

Crystal Growth and Kinetic Behaviour of Pseudoalteromonas espejiana Assisted Biosynthesized Gold Nanoparticles

Pseudoalteromonas espejiana (P. espejiana) is a marine bacterium known for its high resistance to alkalinity. The ability of P. espejiana to reduce Au (III) and biosynthesize gold nanoparticles (AuNPs) is found positive and was confirmed using UV-VIS, EDS, SEM, and TEM studies. Previously, many studies have been reported regarding the crystalline nature of AuNPs; therefore, this research aims at studying the crystal growth behaviour of AuNPs through DLS and TEM studies. Spherically shaped and monodispersed, AuNPs ranging between 5 to 160 nm were obtained with an average particle size of 62 nm. Also, to achieve maximum production of AuNPs, the reaction kinetic study was performed using an ICP-OES method and the effect of various parameters including pH, temperature, rpm, and concentration of substrate was analyzed. During the biosynthesis process, an appropriate phase of nucleation, crystal growth, and saturation was observed and this helped to determine the rate constants and order of reaction. The parameters such as pH profile (pH 9), temperature (30°C), agitation speed (150 rpm), and enzyme substrate ratio (2 : 3) were found to be the best fits for maximum production of low size AuNPs. This demonstrates that in initial few hours, a quick conversion of the ionic gold precursor takes place into metallic gold nuclei, trailed by crystal growth via coalescence of small nuclei. Subsequently, it can be concluded that coalescence processes drive the crystal growth process of AuNPs over a time interval and finally leads to saturation and no newer particle formation in the solution