Topic Review
Visual Field Test
A visual field test is an eye examination that can detect dysfunction in central and peripheral vision which may be caused by various medical conditions such as glaucoma, stroke, pituitary disease, brain tumours or other neurological deficits. Visual field testing can be performed clinically by keeping the subject's gaze fixed while presenting objects at various places within their visual field. Simple manual equipment can be used such as in the tangent screen test or the Amsler grid. When dedicated machinery is used it is called a perimeter. The exam may be performed by a technician in one of several ways. The test may be performed by a technician directly, with the assistance of a machine, or completely by an automated machine. Machine-based tests aid diagnostics by allowing a detailed printout of the patient's visual field. Other names for this test may include perimetry, Tangent screen exam, Automated perimetry exam, Goldmann visual field exam, or brand names such as Humphrey Field Analyzer, Octopus Perimeter, Optopol PTS perimeter, Oculus Easyfield perimeter, Olleyes VisuALL, etc.
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  • 27 Oct 2022
Topic Review
Virtual Screening Algorithms in Drug Discovery
Virtual screening (VS) is an in silico technique used in the drug discovery process. During VS, large databases of molecular structures are automatically evaluated using computational methods. With the use of VS, it is expected to identify molecules more susceptible to binding to the molecular target, typically a protein or enzyme receptor.
  • 563
  • 29 May 2023
Topic Review
Virtual Reality for Rehabilitation
Virtual reality (VR) is a trending, widely accessible, contemporary technology of increasing utility to biomedical and health applications. VR is the technological experience that allows for a full immersion in virtual spaces with which you can interact via specific wearable or using only your hand. A key feature of all VR applications is interaction. VR ranges from non-immersive to fully immersive, depending on the degree to which the user is isolated from the physical surroundings when interacting with the virtual environment. Non-immersive virtual reality allows for interacting with the environment through mouse or joystick; immersive virtual reality, instead, uses tools that are connected to the human body in order to perform the same motor task. Despite the growing evidence of the positive effects of VR in rehabilitation of functional and cognitive abilities, some systems still raised concerns regarding their acceptability with complex clinical populations, as, for example, the older people. In particular, during trials with immersive systems, few adverse events have been described by participants, including headache and dizziness. Finally, little is known about the perceived effect of the exposure at multisensory input during a complex activity, such as treadmill walking with VR in patients during post-stroke rehabilitation to improve balance and gait ability.
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  • 30 Jul 2020
Topic Review
Viral Hepatitis
Viral hepatitis is liver inflammation due to a viral infection. It may present in acute form as a recent infection with relatively rapid onset, or in chronic form. The most common causes of viral hepatitis are the five unrelated hepatotropic viruses hepatitis A, B, C, D, and E. Other viruses can also cause liver inflammation, including cytomegalovirus, Epstein-Barr virus, and yellow fever. There also have been scores of recorded cases of viral hepatitis caused by herpes simplex virus.
  • 521
  • 28 Oct 2022
Topic Review
Video Game-related Health Problems
Game addiction problems can induce repetitive strain injuries, skin disorders or other health issues. Other problems include video game-provoked seizures in patients with epilepsy. In rare and extreme cases, deaths have resulted from excessive video game playing (see Deaths due to video game addiction).
  • 399
  • 05 Dec 2022
Topic Review
Veterinary Diagnostics of Honeybee Diseases
This entry is a review dealing with the veterinary diagnostic approach in honeybee colonies especially in case of common virus diseases. It presents the step-by-step methods a veterinarian should perform when facing an ill honeybee colony and focusses on virus diseases in adult honeybees. 
  • 604
  • 02 Dec 2020
Topic Review
Vertebrate and Genome Annotation Project
The Vertebrate Genome Annotation (VEGA) database is a biological database dedicated to assisting researchers in locating specific areas of the genome and annotating genes or regions of vertebrate genomes. The VEGA browser is based on Ensembl web code and infrastructure and provides a public curation of known vertebrate genes for the scientific community. The VEGA website is updated frequently to maintain the most current information about vertebrate genomes and attempts to present consistently high-quality annotation of all its published vertebrate genomes or genome regions. VEGA was developed by the Wellcome Trust Sanger Institute and is in close association with other annotation databases, such as ZFIN (The Zebrafish Information Network), the Havana Group and GenBank. Manual annotation is currently more accurate at identifying splice variants, pseudogenes, polyadenylation features, non-coding regions and complex gene arrangements than automated methods.
  • 288
  • 07 Nov 2022
Topic Review
Vascular Endothelial Growth Factors
Vascular endothelial growth factors (VEGFs) are primary regulators of blood and lymphatic vessels. Hemangiogenic VEGFs (VEGF-A, PlGF, and VEGF-B) target mostly blood vessels, while the lymphangiogenic VEGFs (VEGF-C and VEGF-D) target mostly lymphatic vessels. Blocking VEGF-A is used today to treat several types of cancer (“antiangiogenic therapy”). However, in other diseases, it would be beneficial to do the opposite, namely to increase the activity of VEGFs. For example, VEGF-A could generate new blood vessels to protect from heart disease, and VEGF-C could generate new lymphatics to counteract lymphedema. Clinical trials that tried to stimulate blood vessel growth in ischemic diseases have been disappointing so far, and the first clinical trials targeting the lymphatic vasculature have progressed to phase II. Antiangiogenic drugs targeting VEGF-A such as bevacizumab or aflibercept neutralize the growth factor directly. However, since VEGF-C and VEGF-D are produced as inactive precursors, novel drugs against the lymphangiogenic VEGFs could also target the enzymatic activation of VEGF-C and VEGF-D. Because of the delicate balance between too much and too little vascular growth, a detailed understanding of the activation of the VEGF-C and VEGF-D is needed before such concepts can be converted into safe and efficacious therapies.
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  • 30 Mar 2021
Topic Review
VALTOCO®
Valtoco® is a new FDA-approved nasal spray version of diazepam indicated for the treatment of acute, intermittent, and stereotypic episodes of frequent seizure activity in epilepsy patients six years of age and older. Although IV and rectal diazepam are already used to treat seizure clusters, Valtoco® has less variability in plasma concentration compared to rectal diazepam. Furthermore, the intranasal administration of Valtoco® is more convenient and less invasive than rectal or IV diazepam, making it ideal for self-administration outside of a hospital setting. Multiple clinical trials have taken place comparing Valtoco® to the oral, rectal, and IV forms of diazepam. Aside from mild nasal irritation and lacrimation, Valtoco® was found to have no increased safety risk in comparison to traditional forms of diazepam.
  • 713
  • 25 Feb 2021
Topic Review
Validation (Drug Manufacture)
Validation is the process of establishing documentary evidence demonstrating that a procedure, process, or activity carried out in testing and then production maintains the desired level of compliance at all stages. In the pharmaceutical industry, it is very important that in addition to final testing and compliance of products, it is also assured that the process will consistently produce the expected results. The desired results are established in terms of specifications for outcome of the process. Qualification of systems and equipment is therefore a part of the process of validation. Validation is a requirement of food, drug and pharmaceutical regulating agencies such as the US FDA and their good manufacturing practices guidelines. Since a wide variety of procedures, processes, and activities need to be validated, the field of validation is divided into a number of subsections including the following: Similarly, the activity of qualifying systems and equipment is divided into a number of subsections including the following:
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  • 19 Oct 2022
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