, Juraj Payer2 and Manfred Herold3
(1)
National Institute for Rheumatic Diseases, Piestany, Slovakia
(2)
Fifth Department of Internal Medicine, Comenius University University Hospital, Bratislava, Slovakia
(3)
Department of Internal Medicine VI, Medical University of Innsbruck, Innsbruck, Austria
Galvanisation A treatment which uses low-frequency direct current. Included are:
Downstream galvanic current (anode proximally, cathode distally) – having analgesic and spasmolytic effects.
Upstream galvanic current (anode distally, cathode proximally) – stimulating the nerves and muscles.
Kowarschik’s galvanic current (two electrodes placed lengthwise, the direction of the current is transversal) – having an analgesic effect.
Four-chamber hydro-galvanic bath – the limbs are put into special baths with water (the direction in the current is from top to bottom or vice versa); it has an analgesic effect and causes hyperaemia. It is used with benefit in patients with involvement of the peripheral joints (rheumatoid arthritis, ankylosing spondylitis, Sjögren’s syndrome).
Gamma/delta T-lymphocytes These are T-lymphocytes which have a T-cell receptor consisting of gamma and delta polypeptide chains on their surface. They make up about 5 % of the T-lymphocyte population.
Gammaglobulins These are fractions of blood serum glycoproteins that have the lowest mobility in alkaline pH during electrophoresis and migrate in the direction of the anode. The majority of immunoglobulins and antibodies belong to this fraction.
Gammopathy A disorder characterised by the overproduction of undesirable immunoglobulins (Ig). Unlike normal Ig, these molecules represent a structurally and functionally homogenous population. The term is derived from a serum protein fraction in which Igs are found (gammaglobulins). Gammopathies (G) develop when a clone of plasma cells or lymphocytes uncontrollably secrete a homogeneous immunoglobulin or its components. Gammopathies may be monoclonal or polyclonal.
In monoclonal G, only one clone of cells (plasma cells or their precursors belonging to B-cells) reproduces beyond control and releases identical immunoglobulin molecules of a certain class or parts of the immunoglobulin molecule (light or heavy chains). With polyclonal G, two or rarely more cell clones reproduce, each of which produces an antibody with different specificity. The undesirable Igs are released into the blood in great abundance and can be determined in the serum by protein electrophoresis or immunofixation technique. Monoclonal gammopathy of undetermined significance (MGUS) is asymptomatic and can have a benign course with a low rate of conversion to malignancy. However, most monoclonal gammopathies are a malignant growth of antibody-producing cells including multiple myeloma, Waldenström’s macroglobulinaemia and heavy chain disease. In multiple myeloma, malignantly growing plasma cells can be found in the bone marrow and produce monoclonal myeloma IgG, IgA, IgD, or IgE often together with Bence-Jones proteins, whose molecule consists of one of the two light chains. In Waldenström’s macroglobulinaemia, there is a malignant growth of atypical lymphocytes secreting an excessive amount of monoclonal IgM. In heavy chain disease, there are incomplete heavy chains of gamma (characteristically of the IgG class), alpha (IgA) or μ (IgM) found in the serum of patients.
Gate control theory of pain Pain is not simply perceived but is modulated by interacting neurons, according to Melzack and Wall. Based on this theory, the nociceptive signal is conducted by thin nerve fibres to the spine where the existence of neurons (in the dorsal horn of the spinal canal) with gate function is suggested. These neurons transmit less or more signals to the brain depending on how wide the ‘gate’ is open. The ‘gate’ is opened by afferentation from thin fibres and closed by afferentation from coarse nerve fibres. The existence of an ‘interpretation centre’ in the subcortical region is suggested. The centre modulates when and under what circumstances these signals are conducted into consciousness as pain. It has been found that nociceptive afferentation can be blocked by ‘closure’ of synapses conducting nociceptive afferentation by the use of substances similar to morphine. These are referred to as endorphins, which are synthesised by the brain (psychological modulation of pain).
Gaucher’s disease Gaucher’s disease is an autosomal recessively inherited lysosomal storage disorder resulting from the deposition of glucocerebrosides (complex glycosphingolipid present in the sheaths of nerve fibres) in the tissues such as the bone marrow, liver, spleen, lungs or brain. This is due to insufficient activity of the enzyme glucocerebrosidase, a consequence of mutations in the GBA gene.
Signs and symptoms: generally include hepatomegaly, splenomegaly, hypersplenism, pancytopenia, neurological symptoms (in some types) and severe pain associated with joints and bones.
Three clinical subtypes include:
1.
Adult or non-neuronopathic (presentation: chronic fatigue, hepatomegaly, splenomegaly, bone pain, swelling of joints adjacent to swollen lymph nodes, anaemia, easy bruising due to thrombocytopenia, short stature and wasting)
2.
Infantile or acute neuronopathic (presentation: hypertonia, strabismus, organomegaly, failure to thrive, neurodegeneration, respiratory complications)
3.
Juvenile or chronic/subacute neuronopathic (presentation: organomegaly, bone pain, neurological involvement such as developmental delay)
Diagnosis is via enzyme or genetic testing as well as observing for biochemical abnormalities such as high alkaline phosphatase.
Management options include enzyme replacement therapy.
Gene The basic unit of inheritance localised on a certain position of the chromosome (locus). The gene can be defined functionally (its product underlying a certain trait in the phenotype) or structurally (a particular section of the DNA molecule or RNA molecule when RNA viruses are implicated). The gene can manifest phenotypically (phenotype) in three cardinal functional forms:
1.
As a section of the DNA chain coding for the primary structure of a polypeptide (structural gene)
2.
As a section of the DNA chain transcribing itself into the primary structure of tRNA, rRNA or other types of RNA that are not subject to translation
3.
As a section of the DNA (or RNA in the case of RNA viruses) with a regulatory function (regulatory gene)
Generalised nodal osteoarthritis (GNOA) – see Osteoarthritis – primary generalised nodal osteoarthritis (GNOA).
Genome All of the genes in a cell (cell genome) or a virus (viral genome) containing the whole hereditary information. Not all these genes must be functionally expressed in the given environment and stage of development. The genome of a prokaryotic cell consists of genes situated in the nuclear DNA and plasmids; the genome of a eukaryotic cell comprises a gene situated in the nucleus and mitochondria and chloroplasts in the herbal cells.
Genu recurvatum (backward curvature of the knee):
1.
Unilateral – hyperextension of the knee associated with instability; most frequently post-traumatically (meniscus, cruciate ligaments)
2.
Bilateral – as the manifestation of local joint laxity or generalised hypermobility (hypermobility syndrome)
Genu valgum (knock-kneed) Inner sides of the knee touch one another, but the person is unable to put legs together. The condition is usually associated with planovalgus foot position. Patients have difficulty walking and running. A slight form of valgus knee position is frequent in pre-school children. The condition will spontaneously recover whilst growing. However, it can also be a result of joint overload in obesity, complication of rickets, renal osteodystrophy or osteogenesis imperfecta or accompany some metabolic defects. Rehabilitation and night splint are used, if therapy is necessary; in serious cases also surgical treatment.
Genu varum (bow-leggedness) Bandy legs (‘O’ shape of legs) are opposite to knocked knees. They appear physiologically in suckling infants and become pronounced after stature verticalisation. They mostly vanish spontaneously but can also be an accompanying sign in arthritis, rickets, postfracture conditions, inflammations and palsy. A more serious finding can mean avascular necrosis of the medial part of proximal tibial metaphysis (Blount disease). If necessary, treatment consists of adjusted shoes, corrective night splints or tibial osteotomy. In adults, the condition may be a complication of osteomalacia or Paget’s disease.
Gestagens Their androgenic activities have a beneficial influence on bone production and mineralisation. They also compete with cortisol for the binding site on osteocyte receptors.
Giant cell arteritis – see Temporal arteritis (TA).
Glandular fever – see Infectious mononucleosis.
Glomerulonephritis (GN) A group of disorders characterised by inflammation and lesion of the renal glomeruli. Immune mechanisms participate in the pathogenesis of the majority of primary and secondary glomerulonephritis. More than 70 % of patients with GN have deposits of immunoglobulins in the glomeruli, frequently in association with complement deposition. Damage to the glomeruli is induced by an inflammatory reaction initiated either by deposits of circulating immune complexes (e.g. in systemic lupus erythematosus) or by cytotoxic antibodies against glomerular antigens. Goodpasture’s syndrome is one example of a cytotoxic antibody reacting with the basal membrane of the glomerulus. The so formed immune complexes (similar to deposits of circulating immune complexes) activate complement which leads to damage of the basement membrane either directly or its chemotactic fragments attract neutrophils which cause damaging inflammation.
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