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Introduction to Cells, DNA, and Viruses
Published in Patricia G. Melloy, Viruses and Society, 2023
Virologists are scientists who study viruses. They typically conduct their work in laboratory settings, although they occasionally conduct their research outside the laboratory and engage in more field work. A virologist might conduct experiments using live animal models (in vivo research) or work with mammalian or other animal cells grown in culture in the laboratory (in vitro research). One commonly used technique to study viral growth in the lab is known as a plaque assay. In this technique, host cells are added to media in a petri dish, and then the cells are infected with virus for several days. Scientists then monitor the clearings in the cell layer created by the virus killing cells in that local area. The clearing is known as a plaque. The number of plaques can be counted to quantify the amount of virus present (Lostroh 2019). The virologist uses all the tools that a typical cell and molecular biologist might use to analyze genes and gene expression into a protein. DNA sequencing is used to compare one virus to another. A powerful technique used to amplify DNA sequences is known as polymerase chain reaction (PCR), and this tool can be used for medical diagnostics to look for viral nucleic acid as well (Nobel Media AB 1993). Techniques such as northern blot and western blot are used to study RNA and protein expression respectively. Scientists may also use online databases or tools to study viral DNA sequences or protein structure.
Infection prevention and control
Published in Nicola Neale, Joanne Sale, Developing Practical Nursing Skills, 2022
An infectious agent is a microorganism with the ability to cause disease and includes bacteria (e.g. Clostridioides difficile and MRSA), viruses (e.g. influenza and hepatitis B) fungi (e.g. Candida, which causes thrush) and protozoa (e.g. Toxoplasma gondii, which causes fetal death or brain damage if infection occurs in early pregnancy). To identify the specific infectious agent and determine appropriate antimicrobial therapy, specimens are collected and sent to the laboratory for microscopy, culture and sensitivity (M, C & S). For example, if a UTI is suspected, a specimen of urine should be sent to the laboratory as soon as possible to identify the presence or otherwise of an infectious organism and inform the medical team of the most appropriate antimicrobial treatment (Wilson 2019). A later section in this chapter focuses on the collection of a specimen. More advanced testing available in some laboratories includes molecular tests such as polymerase chain reaction, which is a biochemical technology used to identify the presence of an organism by detecting the specific DNA or RNA of the suspected organism in a sample. Generally, the turnaround time is quicker for a result from a specimen sent in this way (Wilson 2019).
Detection of Metastatic Tumor Cells in Bone Marrow
Published in Adrian P. Gee, BONE MARROW PROCESSING and PURGING, 2020
Currently there are many tests that can reliably detect 1 tumor cell among 100,000 normal marrow cells. However, in a 50 kg adult, bone marrow may still contain 50,000 tumor cells that go undetected by these sensitive methods. Current research is being conducted to determine if detection of 1 tumor among 1,000,000 normal cells can be attained. Polymerase chain reaction testing of DNA is one technique that may provide this sensitivity. This method is only feasible for tumors that have consistent DNA abnormalities (e.g., chronic myelogenous leukemia) and hence can have only limited use.
Modeling type 2 diabetes in rats by administering tacrolimus
Published in Islets, 2022
JC Quintana-Pérez, F García-Dolores, AS Valdez-Guerrero, D Alemán-González-Duhart, MG Arellano-Mendoza, S Rojas Hernández, IM Olivares-Corichi, JR García Sánchez, JG Trujillo Ferrara, F Tamay-Cach
Insulin resistance consists of a reduced sensitivity of cells to insulin molecules, which results from the compensatory increase in insulin secretion by pancreatic islets during chronic hyperglycemia (Figure 1A). This condition triggers a chain reaction of alterations. The first mechanism affected is a completely insulin-dependent pathway of glucose transport mediated by glucose transporter 4 (GLUT4), followed by insulin-induced phosphorylation of the tyrosine residues in insulin receptors 1, and finally the recruitment of the substrates necessary for glucose deposition in skeletal muscle cells.43,44 The alteration of the latter mechanism can be appreciated in the present study by the difference in the level of blood glucose in the insulin tolerance test at 120 min between the tacrolimus and control groups (65.375 mg/dL vs 52.625 mg/dL, respectively). Although the difference is not significant, the values suggest a decreased activation of insulin receptors 1 caused by an increased phosphorylation of tyrosine residues. In this sense, Pereira et al. noted that an increase in the phosphorylation of Ser and Thr leads to a decline in the activity of PI3K and Akt kinases and defects in the expression and function of GLUT4.41,42,45
The role of vasopressin V1A and oxytocin OTR receptors in protective effects of arginine vasopressin against H2O2-induced oxidative stress in H9C2 cells
Published in Archives of Physiology and Biochemistry, 2022
Vajihe Ghorbanzadeh, Afsaneh Jafarpour, Afshin Pirnia, Naser Pajouhi, Mojtaba Khaksarian, Saeed Veiskarami, Afshin Nazari
Reactive oxygen species (ROS), derived from O2, are important in the maintenance of normal physiological function. However, at high concentration ROS that produced through an uncontrolled chain reaction cause damage to biomolecules and potentially lethal. Therefore, at low/moderate concentration there is an appropriate balance between production and their quenchers, antioxidants (Singh et al.1995). When ROS cellular overproduction overwhelms intrinsic antioxidant capacity, cause oxidative damage to the DNA, proteins, and lead to cellular dysfunction, irreversible cell damage and death, which is implicated in a wide range of disease (Takimoto and Kass 2007). Also, experimental evidence suggests that ROS can induce apoptosis by a variety of mechanisms, including increased protein expression of pro-apoptotic members (Giordano 2005).
Huntington’s disease in Turkey: genetic counseling, clinical features, and outcome
Published in Neurological Research, 2021
Yesim Sucullu Karadag, Busranur Erozan Cavdarli, Rabia Nazik Yuksel
A genetic test was done on 81 individuals in Ankara Numune Education and Research Hospital or Ankara City Hospital’s Genetics Laboratory. About 5 ml of venous blood samples were collected from patients and genomic DNA was extracted from peripheric lymphocytes using QIAamp DNA minikit (Qiagen, Hilden, Germany). Adellgene Huntington Disease kit (Blackhills Diagnostic Resources, Spain) was used for CAG repeat analyses. The main objective of the test is to ensure the amplification of the specific fragments of the first exon of the HTT gene which contains the CAG trinucleotide repeats and to detect their sizes. For amplification, the Polymerase Chain Reaction (PCR) technic was used. The sizes of the DNA fragments were analyzed with the ABI 3130 (Applied Biosystems) sequence system using fluorophore-labeled primers. Finally, measured DNA fragment sizes were converted to CAG repeat numbers using conversion factors. Alleles with a CAG repeat length of 36–39 were defined as a reduced penetrant and ≥40 as fully penetrant [6]. Allele length of less than 36 was considered nonpathogenic.