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Biomedical subjects

J R Baker

Publications and source records attributed to J R Baker.

At least 199 records · Page 11Linked to original sources

[Molecular genetic detection of polyclonal immune response in autoimmune thyroiditis and inflammatory bowel diseases].

Southern blot hybridization techniques were used to analyze the arrangements of the immunoglobulin and the T cell antigen receptor genes in lymphocytes of patients with Graves disease and Hashimoto's thyroiditis as well as in patients with Crohn's disease, chronic ulcerative colitis, and with other gastrointestinal disease. The results indicate that the immune response of autoimmune thyroid disease and inflammatory bowel disease is of polyclonal origin.

Adolescent↗

Development of a human monoclonal antibody from a Graves' disease patient that identifies a novel thyroid membrane antigen.

To investigate the interaction between antibodies and the thyroid gland in Graves' disease, PBL were harvested from seven Graves' disease patients and transformed into lymphoblasts by the addition of EBV in the presence of cyclosporine A. These lymphoblasts were cloned by limiting dilution and then assayed for binding activity to human thyroglobulin, thyroid-stimulating hormone, thyroid microsome, and thyroid as well as guinea pig fat cell membranes. Four patients' cells produced antibody that bound to at least one of the Ag; a single clone from one patient that bound equally well to both thyroid and guinea pig fat cell membranes (but not to other thyroid Ag) was selected for further evaluation. Fusion of these cells with SHM-D33 heteromyeloma cells yielded three cell lines that produced genetically identical mAb. Immunostaining of human thyrocytes with this mAb demonstrated an Ag present on both nuclear and cell membranes. This Ag was identified as an 18,000 m.w. protein band on Western blots of both human thyroid and guinea pig fat cell membranes. The mAb was also able to alter thyrocyte physiology as the short term incubation of this mAb with FRTL-5 cells in vitro inhibited thyroid-stimulating hormone-mediated production of cAMP. Thus, this mAb and the Ag it identifies may be relevant to Graves' disease.

Animals↗

Procarbazine hypersensitivity manifested as a fixed drug eruption.

A case of a previously unrecognized form of hypersensitivity to procarbazine characterized by a nonpigmented fixed drug eruption is reported. Despite skin testing, association of the skin lesion to procarbazine could be determined only by drug rechallenge. Various aspects of procarbazine hypersensitivity reactions as well as the pathogenesis and importance of the fixed drug eruption are discussed.

Adult↗

Fructosamine in the management of gestational diabetes.

The role of maternal serum fructosamine estimation in the management of gestational diabetes was assessed in 78 consecutive patients over a 3-year period. Fructosamine results correlated significantly with mean plasma glucose levels over a 1- to 3-week interval, with the closest association being in the preceding week. Eighty-five percent of women with gestational diabetes had peak serum fructosamine levels above the normal range. If maternal levels exceeded 3.2 mmol/L, there was an 88% chance of abnormal glucose tolerance post partum. Our aim of management was a serum fructosamine level less than 2.5 mmol/L; patients who achieved this goal by 35 to 37 weeks' gestation had fewer obese babies with lower cord insulin and C-peptide levels as compared with neonates of mothers with elevated fructosamine concentrations.

Birth Weight↗

Clinical relevance of the substitution of different brands of sustained-release theophylline.

In order to assess whether clinically important changes in serum theophylline concentrations occur when patients switch their brand of slow-release (SR) theophylline, 10 subjects with asthma were administered the same dose of four different SR theophylline formulations for 2-week periods in a random, double-blinded, crossover manner. Analysis of the data revealed significant differences in mean peak-to-trough fluctuations of serum theophylline concentrations between the formulations of SR theophylline, which varied from 60% to 106% of trough concentration (p less than 0.0001, analysis of variance). On at least one occasion in every subject, switching between brands of SR theophylline was responsible for raising the serum theophylline concentrations outside the accepted therapeutic range, and this was associated with symptoms of toxicity in five of the subjects. Worsening pulmonary functions were observed in two of the subjects whose switching resulted in lowered theophylline concentrations. Many of the formulation-related changes in theophylline concentrations appeared to be idiosyncratic and could not be predicted by the overall bioavailability differences between the drugs. These results argue against the open substitution of these formulations and suggest that if patients are switched between different brands of SR theophylline, their serum theophylline concentrations need to be closely monitored.

Adult↗

Osteoclast-type giant cell neoplasms of the parotid gland.

The parotid gland is added to the list of parenchymal organs, notably the pancreas, in which osteoclast-like cells appear as constituent cells in their neoplasms. The cells' role in the neoplasms is a reactive one or, more rarely, as an integral element in an osteoclast-type giant cell neoplasm or so-called osteoclastoma. Distinctive in histological appearance, the osteoclast-type giant cell neoplasm is a malignant lesion that, to date, has been described only in the pancreas and parotid glands. This report presents examples of each type of giant cell lesion in the parotid gland.

Aged↗

Endothelium-dependent effects of acetylcholine in rat aorta: a comparison with sodium nitroprusside and cromakalim.

1. The mechanisms involved in the mechano-inhibitory effects of acetylcholine (ACh) have been compared with those of sodium nitroprusside (SNP) and cromakalim on the rat isolated thoracic aorta. 2. Relaxations produced by ACh were endothelium-dependent, whereas those produced by SNP or cromakalim were endothelium-independent. 3. ACh, cromakalim and SNP relaxed established contractions produced by noradrenaline (NA) and KCl (20 mM) and these relaxations were well-maintained. 4. SNP was a relatively effective inhibitor of contractions produced by KCl (80 mM). ACh was relatively ineffective and cromakalim was without effect against such contractions. 5. Membrane potential and cyclic GMP concentrations were higher in tissues with an intact endothelium whereas rubbed tissues had a higher 86Rb efflux rate coefficient. 6. ACh and cromakalim produced a transient and long-lasting hyperpolarization, respectively. These changes were accompanied by increases in the 86Rb efflux rate coefficient with a time course comparable to that of the electrical changes. 7. Tissue cyclic GMP concentrations were significantly increased in the presence of ACh or SNP, whereas cromakalim had no effect. 8. Transmission electron microscopy showed the presence of endothelial cells on intact tissues. On rubbed preparations, such cells were absent and some damage to the underlying smooth muscle cells was detected. 9. It is concluded that at least two inhibitory substances are released from the endothelial cells by ACh. One of these increases tissue cyclic GMP concentrations and produces an electrically-silent relaxation. The other produces a transient hyperpolarization associated with the opening of 86Rb-permeable K-channels. This event may serve to initiate relaxation processes and to close any open voltage-dependent Ca-channels.

Acetylcholine↗

Natural killer cell activity and serum autoantibodies in women with postpartum thyroiditis.

Postpartum thyroiditis (PPT) is a form of painless lymphocytic thyroiditis which is thought to be caused by an exacerbation of underlying subclinical autoimmune thyroid disease during a postpartum period of immune rebound. The purposes of this study were to analyze natural killer cell (NK) functional activity and antibody-dependent cell-mediated cytotoxicity (ADCC) of peripheral blood mononuclear cells in patients with PPT compared to those in normal nonpostpartum and postpartum women. NK activity and ADCC were determined by specific lysis of 51Cr-labeled K562 human erythroleukemia tumor cells at varying effector (mononuclear cell) to target cell ratios. Nineteen PPT patients between 4-9 months [mean, 6.5 +/- 0.4 (+/- SE)] postpartum were compared to 20 nonpostpartum women, 31 healthy women between 4-9 months (6.7 +/- 0.3) postpartum, and 14 women 2 days after delivery. There were significant differences in the NK functional activities of the 4 groups (F = 7.95; P = 0.0002). The mean NK activities, as measured by percent specific lysis at an effector to target cell ratio of 10:1, were 31.1 +/- 3.3%, 20.9 +/- 2.3%, 22.5 +/- 2.8%, and 11.5 +/- 2.0% in the nonpostpartum, PPT, postpartum, and 2-day postpartum groups, respectively. Specific lysis by ADCC was not significantly different from lysis by NK activity in any group. The PPT, postpartum, and 2-day postpartum groups had significantly lower NK activity compared to that in nonpostpartum women (P less than 0.05). Both the PPT and postpartum women had higher NK activities than the 2-day postpartum women (P less than 0.05). However, there were no significant differences in the NK activities of the PPT patients compared to those of the healthy postpartum women. Patients with PPT were also found to have associated autoimmune dysfunction. The PPT group had significantly higher serum antinuclear antibody titers; 8 of 24 patients (33%) had titers of 1:160 or greater compared to only 2 of 29 healthy postpartum women (7.4%; P less than 0.05). Seven of the PPT patients had serum immune complexes, and 3 had TSH receptor antibodies. We conclude that functional NK activity and ADCC in peripheral lymphocytes of PPT patients are not different from those in healthy postpartum women; however, the postpartum women had significantly decreased activity compared to that in nonpostpartum women. These data emphasize the importance of studying healthy postpartum women in investigations of PPT, since the immunological changes in pregnancy and the postpartum period remain largely undefined.

Adult↗

Immunoglobulin and T cell antigen receptor gene arrangements indicate that the immune response in autoimmune thyroid disease is polyclonal.

To further define the degree of heterogeneity of the antibody and cellular immune responses in autoimmune thyroid disease, we used Southern blot hybridization techniques to analyze the arrangements of immunoglobulin and T cell antigen receptor genes in circulating lymphocytes and in those infiltrating the thyroid gland in nine patients with thyrotoxicosis due to Graves' disease and five patients with Hashimoto's thyroiditis. The sensitivity of these techniques was sufficient to detect a monoclonal population when there was as little as 1% clonal involvement in a mixed cell population. In the patients studied, DNA from non-T peripheral blood cells and non-T intrathyroid lymphocytes had only a germline gene pattern and no clonal nongermline rearrangements of immunoglobulin genes, as assessed using an immunoglobulin joining heavy chain (IgJH) gene probe. An analysis of the DNA from peripheral blood T cells or intrathyroidal lymphocytes revealed polyclonal gene rearrangement patterns and no clonal nongermline rearrangements of the T cell antigen receptor-beta and -gamma genes, as assessed using T constant-beta and T joining -gamma gene probes. These results indicate that the lymphocytes in peripheral blood and those infiltrating the thyroid gland in patients with autoimmune thyroid disease are of polyclonal origin.

Adult↗

Autoantibodies to insulin are present in sera of patients with autoimmune thyroid disease.

It has been clinically suspected that patients with autoimmune thyroid disease are at an increased risk of developing other autoimmune diseases later in life. To determine the presence and potential importance of a more generalized deregulation of immune response in patients with Grave's disease and Hashimoto's disease, sera from 33 patients with Graves' disease and 16 patients with Hashimoto's disease were screened for the presence of anti-insulin antibodies and anti-insulin-receptor antibodies. An enzyme-linked immunosorbent assay was used to identify the presence of IgG against human insulin. The optical density indicating the presence of IgG against insulin in sera from patients with Graves' disease averaged .172 +/- .024 (mean +/- SE; range .010-.802), compared to the mean normal value of .098 +/- .0009 (range .012-.238) in 33 control subjects. Ten of 33 patients with Graves' disease had values greater than .200, whereas control sera values were less than .200 in all but one case (P less than .005, Graves' sera vs. controls). The sera from patients with Hashimoto's disease had a mean optical density of .110 +/- .016, with 15 of 16 values between .010 and .200. These values were not significantly different from controls with an insulin-binding inhibition assay. Anti-insulin-receptor antibodies were not detected in any of 33 patients with Graves' disease, and cytoplasmic islet cell antibodies were not detected in sera from seven patients with Graves' disease who had insulin-binding antibodies. These data support the hypothesis that the immunologic response in autoimmune thyroid disease may be more heterogeneous and polyclonal than previously believed.

Autoantibodies↗

Seronegative Hashimoto thyroiditis with thyroid autoantibody production localized to the thyroid.

A patient without serologic evidence of an autoimmune disorder had a thyroidectomy for neck compression caused by her goiter. Histologic examination of the gland revealed pathologic changes compatible with Hashimoto disease, and lymphocytes isolated from her thyroid gland were transformed into lymphoblastoid cells in vitro by Epstein-Barr virus in the presence of cyclosporine. These cells produced antibodies against thyroglobulin, thyroid microsome, thyrocyte membrane, and thyrotropin, whereas lymphoblastoid cells produced from the patient's peripheral blood lymphocytes showed no antithyroid activity. Several human monoclonal antibodies were produced from the intrathyroidal lymphocytes by fusion with the SHM-D33 heteromyeloma, and the resulting cell lines produced antibodies with high-affinity binding specific for thyroid antigens. These studies show that lymphocytes capable of producing antithyroid antibodies can be present in the thyroid glands of patients with Hashimoto disease without evidence of a peripheral immune response, thus indicating that Hashimoto disease can exist as an organ-restricted autoimmune disorder.

Adipose Tissue↗

Eponyms.

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Eponyms↗

Inaccuracy in measuring glycated albumin concentration by thiobarbituric acid colorimetry and by boronate chromatography.

We compared thiobarbituric acid colorimetry and boronate chromatography for measuring glycation of serum proteins. With 14C-glycated human albumin as a test material, both methods were acceptably linear and precise. However, comparable estimates (mmol/L) of albumin glycation ranged from 0.22 for thiobarbituric acid to 0.05 for boronate, representing yields relative to [14C]glycosylprotein of 42% and 10%, respectively. The low yield with thiobarbituric acid was corroborated independently on the basis of kinetic differences between the reactions of fructose standards and of glycosylprotein, leading to underestimation of glycosylprotein concentration. The lower estimate of glycosylprotein by boronate chromatography was related to an apparent requirement for two [14C]glyco groups per albumin molecule to effect binding.

Chromatography↗

Cartilage proteoglycan aggregates. The link protein and proteoglycan amino-terminal globular domains have similar structures.

Cartilage proteoglycan aggregates contain two components (proteoglycan monomer and link protein) which interact with each other and with hyaluronic acid. Data from amino acid sequence analysis are presented that shows that a domain of the proteoglycan, the hyaluronic acid binding region, which interacts with link protein and hyaluronic acid is very similar to link protein in terms of its primary structure. However, the pattern of glycosylation in the hyaluronic acid binding region is different from that found in link protein. After removal of N-linked oligosaccharides, the tryptically prepared hyaluronic acid binding region from rat chondrosarcoma has a mass by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of 43 +/- 2 kDa. The COOH-terminal two-thirds of rat chondrosarcoma link protein, starting at residue 105, has 41.3% identity with a similar region in the hyaluronic acid binding region. We show that, in addition to the hyaluronic acid binding region, proteoglycan contains another region with similarity to the two repeating loop structures in the COOH-terminal two-thirds of link protein. This presumably corresponds to the second globular domain reported in rotary shadowing studies of cartilage proteoglycans. We have deduced the positions of all of the disulfide bonds in the hyaluronic acid binding region and find them to be in the same positions as would be expected from comparison of these sequences with link protein.

Amino Acid Sequence↗