Items tagged “definition”
93 results found
Article
Optic neuropathy
Optic neuropathy is a broad term and can result from a variety of causes.
Pathology
genetic
Leber hereditary optic neuropathy
compression or trauma (traumatic optic neuropathy)
optic nerve sheath meningioma
progressive diaphyseal dysplasia
thyroid-associated orbitopathy
shear injury
inf...
Article
Phase 0 clinical trials
Phase 0 clinical trials are the first step in evaluating a possible new drug on humans, and are designed to evaluate the pharmacodynamics and pharmacokinetics of the drug in humans. They are typically performed on a small number of subjects (e.g. a dozen or so) who are administered subtherapeut...
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Phase 1 clinical trials
Phase 1 clinical trials, occur after a drug successfully passes phase 0 trials, and aim to assess dosage, safety and identify side effects. They are performed typically on 20–80 individuals.
Article
Phase 2 clinical trials
Phase 2 clinical trials occur after a drug (or treatment) has successfully passed both Phase 0 and Phase 1 trials. Phase 2 clinical trials are performed on larger number individuals (e.g. ~200) and aim to identify whether or not it is effective. Additional data on safety and side-effects is also...
Article
Phase 3 clinical trials
Phase 3 clinical trials are the final hurdle to establishing a drug or experimental treatment is safe and effective. They are expensive and often long processes recruiting large numbers of individuals (e.g. 1,000 to 3,000). They are aimed at confirming Phase 2 findings (effectiveness and side-ef...
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Phase 4 clinical trials
Phase 4 clinical trials occur after a new drug or treatment has been successfully marketed. They are aimed at defining optimal use, identifying additional side-effects or risks, and comparing the treatment to other existing therapies.
Article
Transudate
A transudate is a collection of fluid that has a relatively low specific gravity and protein concentration. They occur secondary to increased hydrostatic pressure or reduced colloid oncotic pressure:
left ventricular failure (increased hydrostatic pressure)
hypoalbuminemia (decreased colloid o...
Article
Exudate
An exudate is a collection that has a relatively high specific gravity and protein concentration. They occur as the result of an inflammatory process that either increases the permeability of the surrounding membrane or disrupts the ability of resorption of fluid. They may be secondary to:
infe...
Article
Radiologist
What is a radiologist?
A radiologist is a specialist doctor who uses medical imaging such as x-ray, MRI, CT, ultrasound and angiography, to diagnose and treat human disease or injury. Radiologists undergo lengthy training and assessment in order to be accredited by relevant governing boards and...
Article
Transcriptome
The transcriptome refers to the set of all transcribed RNA, including the messenger RNA (mRNA), which is eventually is translated into proteins, as well as non-coding RNA molecules (e.g. transfer RNA (tRNA), ribosomal RNAs (rRNA), microRNA, etc.).
Unlike the genome, which is fixed (barring spo...
Article
Geophagy
Geophagy is the intentional ingestion of earth, soil or clay and is a form of pica. This practice is not uncommon in the southern regions of the United States or provinces of Africa. It is found most commonly in children and pregnant women 3,4. Although geophagy may be seen in the context of a v...
Article
Valgus vs varus
The terms valgus and varus refer to angulation (or bowing) within the shaft of a bone or at a joint in the coronal plane.
It is determined by the distal part being more medial or lateral than it should be. Whenever the distal part is more lateral, it is called valgus. Whenever the distal part i...
Article
Juxtacortical
Juxtacortical is a general term and merely denotes 'next to cortex' and can be used in a variety of context depending on the structure (e.g. bone, brain, kidney etc.).
Juxtacortical brain lesions
The term juxtacortical is most commonly encountered in the brain in the context of multiple scler...
Article
Subcortical U-fibers
Subcortical U-fibers, also known as short association fibers, represent connections between adjacent gyri of the brain, located within the cortex or immediately deep to it in the very outer parts of the subcortical white matter 1.
They are among the last parts of the brain to myelinate, as lat...
Article
Adnexa (disambiguation)
Adnexa (single/plural) is a general term that refers to the accessory structures of an organ.
Adnexa have been described in relation to:
cutaneous/skin adnexa
hair follicles, sweat glands, nails
adnexa mastoidea
structures in the mastoid (posterior) wall of the middle ear, e.g. mastoid antr...
Article
Trochlea (disambiguation)
Trochlea (sing., pl. trochleae) is a general term that refers to an anatomic structure that resembles the grooved part of a pulley system.
Trochlea have been described in:
orbit:
trochlea of the superior oblique muscle
trochlear nerve (CN IV)
humeral trochlea
femoral trochlea
trochlea of ...
Article
Non-Hodgkin lymphoma
Non-Hodgkin lymphoma (NHL) is a neoplasm of the lymphoid tissues originating from B cell precursors, mature B cells, T cell precursors, and mature T cells. It includes all types of lymphomas apart from Hodgkin lymphoma.
See the WHO classification of haematolymphoid tumors for further informatio...
Article
Interstitial edematous pancreatitis
Interstitial edematous pancreatitis is one of the two subtypes of acute pancreatitis. It is normally referred to as "acute pancreatitis" or "uncomplicated pancreatitis" in day-to-day use. Please refer to the article on acute pancreatitis for further details.
Article
Sulcal effacement
Sulcal effacement is a local secondary sign of mass effect in the cranium. Any lesion exerting mass effect on brain parenchyma can push adjacent gyri together, thereby displacing the CSF from the sulci.
It is greatest at the site where the cause of the mass effect is located (e.g. tumor, hemorr...
Article
Derotation screw
A derotational screw is an orthopedic device used for internal fixation of fractures to, unsurprisingly, limit rotation of the fracture 1.
They are applied across fractures at risk of rotation and hence avascular necrosis.
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