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Biomedical subjects

A Miller

Publications and source records attributed to A Miller.

At least 487 records · Page 27Linked to original sources
PubMed1986

Antibody response to the herpes simplex virus type 2 AG-4 antigen in guinea pigs with genital herpes infections.

Female guinea pigs, inoculated intravaginally with a herpes simplex virus-type 2 (HSV-2) strain M1, developed typical symptoms of a primary and recurrent genital herpes infection. Sera from HSV-2 infected guinea pigs taken during the primary or recurrent stages of the genital infection contained complement (C)-fixing antibody which reacted with an apparent type specificity to an early 4 h HSV-2 infected cell extract (AG-4) when compared to a 4 h HSV-1 infected cell extract. This C-fixing anti-AG-4 activity was shown to be associated with the IgG2 subclass and directed primarily against HSV-2 infected cell polypeptide (ICP)6 and ICP8. Furthermore, C-fixing anti-AG-4 levels remained constant after the primary infection and during recurrences for over 6 months. Thus, while the anti-AG-4 response in guinea pigs was of the IgG type, it varied from that found previously in human genital HSV-2 sufferers which was of the IgM type. Also, while an IgG anti-AG-4 response in human genital HSV-2 sufferers is associated with a reduction in the number of recurrences, this reduction is not apparent in the guinea pig model.

Animals↗
PubMed1986

Osteogenesis imperfecta: an x ray fibre diffraction study.

The use of x ray fibre diffraction to study the molecular architecture of healthy and diseased human tendon is described. The three dimensional structure of human (finger) tendon is derived to high resolution and is shown to be very similar to that reported for rat tail tendon. In particular the presence of the 38 A row line in the diffraction pattern suggests that a high degree of lateral order within the collagen fibrils is a more widespread feature of tendon tissue than was formerly realised. Axially projected electron density maps of the 670 A unit repeat of the collagen fibrils of this tissue, and of tendon tissue from three cases of osteogenesis imperfecta (OI), are calculated and compared. The results are in agreement with recent biochemical studies in suggesting that type I (Sillence) OI is principally a quantitative, rather than a qualitative, defect of type I collagen biosynthesis. The features by which a molecular lesion may be recognised and characterised from diffraction data are discussed.

Animals↗
PubMed1986

Localization of vitamin D-dependent active Ca2+ transport in rat duodenum and relation to CaBP.

Vitamin D-replete (+D) and vitamin D-deficient (-D) rats received by intraperitoneal injection varying amounts of 1,25-dihydroxyvitamin D3, and 4 h (+D) or 9 h (-D) later everted duodenal sacs were prepared to evaluate active calcium transport, i.e., the amount of calcium found in the serosal fluid. At the same time, duodenal calcium-binding protein (CaBP) content was measured. Calcium transport was a close positive function of CaBP content. It was not detectable when CaBP content was zero and increased linearly without plateauing as CaBP content increased to 100 nmol calcium bound/g mucosa. Trifluoperazine (TFP) inhibited active calcium transport in a concentration-dependent manner. Experiments using vesicles prepared from brush-border or basolateral membranes indicated that TFP inhibited the calcium-extrusion process, with virtually no effect on calcium entry. It is concluded that vitamin D exerts its major regulation of active calcium transport in the rat duodenum via CaBP on transport steps beyond brush-border entry.

Animals↗
PubMed1986

Evaluation of an enzyme-linked immunosorbent assay for the measurement of autoantibodies against eye muscle membrane antigens in Graves' ophthalmopathy.

We have tested for antibodies against human and pig eye muscle membrane antigens in the serum of patients with Graves' ophthalmopathy using an enzyme-linked immunosorbent assay (ELISA). Several different membrane preparations were used as source of putative antigen including a 100,000 X g pellet, a pellet depleted of the 100,000 X g (microsome) fraction, and solubilized membranes. With eye muscle membrane pellets there were no significant differences for either serum or immunoglobulins between patients with ophthalmopathy, those with autoimmune thyroid disorders without eye disease, and normal subjects for either human or pig membranes, although tests were positive determined from the upper limit of normal in a few patients with or without eye disease. This was the case regardless of the enzyme-antibody conjugate used, the membrane protein concentration or serum or immunoglobulin dilution. Pre-absorption of tissue fractions, serum, or immunoglobulins, with red blood cells or liver powder, eye muscle membranes or skeletal muscle membranes did not significantly reduce back-ground binding which was often very high, or enhance the difference between patients with ophthalmopathy and normal subjects. It was found that non-specific binding to the plastic surface of the microplates and/or tissue proteins, the presence, in human tissues, of blood-derived immunoglobulins which gave strong reactions in the ELISA, and variable fixation of membrane pellets to the plates were factors which made ELISA unsatisfactory when crude membrane pellets were used as antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Amino acid residues distinct from the determinant region can profoundly affect activation of T cell clones by related antigens.

Hen egg-white lysozyme (HEL)-specific T cell clones derived from the C57BL/6 strain were found to be about 100-fold more sensitive to the closely related ring-necked pheasant lysozyme (REL) in a dose-dependent proliferation assay. This apparent heteroclicity of REL was independent of the fine specificity of the clones. However, when stimulations by corresponding cyanogen bromide-cleaved peptides (L2H and L2R) known to contain the determinants recognized by all of the clones were compared, the preference for REL was lost. Conversely, an HEL-specific, I-Ad-restricted clone that did not respond to REL responded equally well to L2H and to L2R. Because the HEL/REL reactivity differences involved only the T cells and antigen-presenting cells (APC), and were correlated with differential sensitivity to the lysosomotropic drug chloroquine, it appears that the reactivity differences relate to the manner in which lysozymes are processed by the APC. Thus, conclusions about T cell "clonal specificity," usually attributed to differences in recognition of the determinant regions, may in some cases reflect differential antigen handling that depends on sites on the molecule distant from the determinant.

Amino Acid Sequence↗
PubMed1986

Clinical significance of a new autoantibody against a human eye muscle soluble antigen, detected by immunofluorescence.

The clinical significance of a circulating autoantibody against a recently identified soluble human eye muscle-derived antigen was studied in patients with Graves' ophthalmopathy and autoimmune thyroid disorders. Tests were positive in 73% of patients with Graves' ophthalmopathy, including six of seven with no associated thyroid disease (euthyroid Graves' disease). Tests were also positive in 27% of patients with hyperthyroidism but no clinically apparent eye disease, in 13% of patients with Hashimoto's thyroiditis without eye disease, in two of 12 patients with subacute thyroiditis, in one of 20 patients with nonimmunological thyroid disorders but in none of 39 normal subjects. There were significant positive correlations between serum levels of the antibody (expressed as a titre) and the severity of the eye muscle component quantified as an index as well as the duration of the eye disease. Antibodies were detected in three of five patients with only lid lag and state who subsequently developed active ophthalmopathy, in six of nine patients who developed eye disease after treatment of their hyperthyroidism and in one of eight first degree relatives of patients with Graves' ophthalmopathy. In addition three of the 12 patients with autoimmune thyroid disease without apparent eye involvement, but positive antibody tests, have developed ophthalmopathy since the time of testing. These findings suggest that tests for antibodies against a soluble human eye muscle antigen may be useful clinically as a diagnostic test and to predict the onset of eye disease in predisposed patients and subjects.

Adolescent↗
PubMed1985

Distinct recognition phenotypes exist for T cell clones specific for small peptide regions of proteins. Implications for the mechanisms underlying major histocompatibility complex-restricted antigen recognition and clonal deletion models of immune response gene defects.

Using synthetic peptides as antigens, it was found that T cell clones of a given haplotype specific for 13-16 amino acid peptides could be clearly distinguished by the varied influence of amino acid substitutions on recognition. This was true for different antigenic determinants within peptides 81-96 and 74-86 of hen egg-white lysozyme, recognized in the context of the I-Ab and I-Ak molecules, respectively. Considerable complexity was demonstrated in the induced T cell repertoire specific for apparently single determinants, which implies that diversity of T cell recognition approaches that for B cells. The implications of the degeneracy of T cell recognition are discussed in the context of mechanisms through which Ia molecules restrict recognition and theories of Ir gene defects.

Animals↗
PubMed1985

Ca2+-induced phase separation in black lipid membranes and its effect on the transport of a hydrophobic ion.

Voltage jump-current relaxation studies have been performed with dipicrylamine-doped black membranes of binary lipid mixtures. As in the case of the carrier-mediated ion transport (Schmidt, G., Eibl, H. and Knoll, W. (1982) J. Membrane Biol. 70, 147-155) no evidence was found that the neutral lipid phosphatidylcholine (DPMPC) and the charged phosphatidic acid (DPMPA) are heterogeneously distributed in the membrane over the whole range of composition. However, besides a continuous dilution of the surface charges of DPMPA by the addition of DPMPC molecules, different structural properties of mixed membranes influence the kinetics of the dipicrylamine transport. The addition of Ca2+ to the electrolyte induces a lipid phase separation within the membrane into two fluid phases of distinctly different characteristics of the translocation of hydrophobic ions. Thus, it is possible to determine a preliminary composition phase diagram for the DPMPA/DPMPC mixtures as a function of the Ca2+ concentration.

Adsorption↗
PubMed1985

Return to alertness after brain-stem hemorrhage. A case with evoked potential and roentgenographic evidence of bilateral tegmental damage.

After a 65-year-old man had received anticoagulation therapy for brain-stem ischemia, a large, bilateral pontomesencephalic hemorrhage developed in the ischemic region. He survived a period of being "locked in" to attain a limited functional recovery. When he first became alert, brain-stem auditory evoked potentials and short-latency somatosensory evoked potentials (SEPs) demonstrated bilateral brain-stem damage; computed tomography revealed a bilateral tegmental hematoma. Results of repeated studies changed little as clinical improvement occurred. Recovery from brain-stem hemorrhage is rare, and return of consciousness with bilateral tegmental involvement is even more rare. The short-latency SEPs are useful in defining the extent of brain-stem damage, but they evaluate structures distinct from those regulating consciousness and cannot predict a return to alertness.

Aged↗