Amino acid transport by synaptosomes isolated from post mortem human brain

Summary Synaptosomes isolated from post mortem human brain release the transmitter amino acids upon depolarisation. Active preparations can be isolated for up to 24 hours post mortem. The amount of depolarisationinduced release of the transmitter amino acids is correlated with the rate of oxygen uptake. Only when this correlation is taken into consideration would it be possible to detect disease-related changes in presynaptic aminoacid transport systems.     

The functional significance of sacroiliitis and ankylosing spondylitis in Reiter's syndrome

The frequent development of sacroiliitis and ankylosing spondylitis (AS) in patients suffering from Reiter's Syndrome (RS) has been stressed by a number of authors. This study was designed to ascertain the frequency of these problems in our RS patients, whether they were related to other clinical features of RS and what was the extent of the resulting disability. Fifty-five patients (50 men and 5 women) with RS with a mean duration of 9.3 years were assessed radiologically to determine the prevalence of sacroiliitis and thoracolumbar syndesmophyte formation. These radiological findings were correlated with HLA-B27, clinical features and functional status. Sacroiliitis was found in 22 patients (40%) but was mild in severity, frequently asymmetrical and very rarely associated with syndesmophyte formation. Sacroiliitis occurred significantly more commonly in patients with iritis and/or a prolonged disease duration (p less than 0.05) but although it was also found more frequently in HLA-B27 positive patients this was not significant (0.1 greater than p greater than 0.05). Some restriction in back movement was observed in 31 patients (56.3%) but only two patients satisfied New York criteria for AS and just one was functionally impaired by his back disease. Although the frequent finding of sacroiliitis in RS may provide an interesting insight into the interrelationship between RS and AS, our study shows that this sacroiliitis is commonly asymptomatic and does not provide a problem in management.     

Immunologic aspects of Graves' and Hashimoto's diseases

It is hypothesized that Graves' hyperthyroidism, exophthalmos, and Hashimoto's thyroiditis (as well as other closely related organ-specific autoimmune disorders) may each be attributed to separate, albeit very closely related, inherited isolated defects in immunoregulation (possibly specific defects in suppressor T lymphocyte function). The gene responsible for each of these disorders may lie in close linkage disequilibrium with HLA-Dw3 on chromosome 6. Each of the defects in immunoregulation, however, would permit a specific randomly mutating self-reactive “forbidden” clone of “helper” T lymphocytes to survive (if it chanced to appear), interact with its complementary antigen, and induce a cell-mediated immune response. This would not require any alteration of the antigen, only the mere availability of the specific antigen. The clone of self-reactive T lymphocytes, so arising and escaping immunoregulation, would presumably then expand upon interaction with its antigen, and consequently direct and cooperate with appropriate groups of (already present) B lymphocytes, which in turn would produce specific immunoglobulins that appear necessary for the full expression of these disorders. Adjunctive roles for immune complexes, nonspecific cells (macrophages, “killer” cells), and chemical mediators are undoubtedly important. The role of stress in the induction of hyperthyroidism may be by means of its effect in further reducing immunosuppression in those persons with only a partial isolated defect. On the other hand, remissions may be brought about by restoring immunoregulation to its previous state. Those persons having an isolated complete defect in immunoregulation would not be expected to achieve remissions, except by destruction of thyroid parenchyma.     

Gilles de la Tourette syndrome is not linked to D2-dopamine receptor

Gilles de la Tourette syndrome has an important genetic component; the pathophysiology of this disorder may involve the dopamine system. We tested a D2-dopamine receptor (locus DRD2, recognized by probe hD2G1) for genetic linkage with Gilles de la Tourette syndrome. Using a genetic linkage map of the region of DRD2 on the long arm of chromosome 11 and restriction fragment length polymorphism data from a total of four markers (DRD2 itself, D11S84, D11S29, and PBGD), we were able to exclude linkage of this candidate gene and Gilles de la Tourette syndrome in two extended kindreds segregating for Gilles de la Tourette syndrome. This rules out causation of Gilles de la Tourette syndrome by mutation in DRD2 in the kindreds studied under the genetic assumptions we employed; use of the map and multipoint linkage analyses also allowed us to exclude a Gilles de la Tourette syndrome susceptibility locus from a larger genetic region.     

Properties of a new carvable composite dental filling material

The chemical principles and physical properties of a new composite system, which apparently cures in a two-step process to allow time for hand carving to the proper anatomic contours, are described. The new material appears to have better in vitro wear resistance than an older composite filling material.