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Biomedical subjects

A Shneyour

Publications and source records attributed to A Shneyour.

At least 19 recordsLinked to original sources
PubMed1995

Comparison of the proteins of middle ear effusion with human mast cell proteins.

In order to clarify the role of mast cells in the aetiology of secretory otitis media (SOM), we compared the protein components of middle ear effusion (MEE) with human mast cells using acrylamide gradient gel electrophoresis and electrofocusing methods. This first direct comparison between the proteins of MEE and human mast cells has been made possible by a method developed in our laboratory for cultivation of human mast cells in tissue culture. On electrophoresis, we found that out of 12 bands of MEE proteins that were different from the serum, seven (58 per cent) had a similar electrophoretic migration rate (Rx) to mast cells. On electrofocusing, three of the four bands of MEE had a similar Rx to the mast cells. We have shown that proteins of mast cells and MEE had similar Rxs. Therefore, our study supports previous studies which suggests that mast cells play an important role in the aetiology of SOM.

Basophils↗
PubMed1993

A possible effect of ultrasound on RNA synthesis in cultured amniocytes.

The effect of both diagnostic and therapeutic ultrasound on cellular RNA synthesis was investigated in amniocytes cultured in F-10 medium enriched with fetal calf serum. The rate of RNA synthesis was tested using incorporation of H3 uridine, which was added following the exposure to acid insoluble RNA. Cultured amniocytes which were not exposed to ultrasound served as the control. Different results were obtained following the two ranges of exposure. A significant decrease in RNA synthesis was demonstrated immediately following diagnostic ultrasound and a certain increase in RNA synthesis was demonstrated soon after exposure to therapeutic doses. These effects were transient and could not be shown 24 hours later. It is concluded that the routine use of ultrasound can not have any clinical implications on RNA synthesis.

Amniotic Fluid↗
PubMed1992

[Antibodies against double-stranded and single-stranded DNA in the aged].

Sera from 183 healthy, elderly subjects and 92 young, control subjects were tested by the Elisa method for antibodies against double-stranded (ds) and single-stranded (ss) DNA, and sera from the elderly were tested for antinuclear antibodies as well. Significantly higher levels of anti-ss-DNA were found in the elderly, but levels of anti-ds-DNA did not differ significantly; no sera positive for anti-ds-DNA were found. levels of antibodies to DNA were similar in men and women. In those 85 and over, mean levels of anti-ds-DNA were lower than in those 65-84 (63 vs. 44, p less than 0.05). 13 of those over 65 (7.1%) tested positive for antinuclear factor, 2 of whom had positive titers of anti-ss-DNA. The results of this study support the hypothesis that elevated levels of anti-ss-DNA are age-related and not disease-related.

Aged↗
PubMed1990

A case of transient hypothyroidism: sequential serum measurements of autoantibodies inhibiting thyrotropin-stimulated thyroid cAMP production in a neonate.

Transient neonatal hypothyroidism has been observed in three successive offspring of a mother with autoimmune thyroiditis. Thyroxine replacement therapy was initiated in a 23-year-old woman with overt clinical and laboratory findings of non-goitrous primary hypothyroidism. While on such treatment, she gave birth to three infants manifesting hypothyroidism immediately after birth. The neonates were treated with thyroxine replacement therapy which was discontinued in the three siblings at ages 2 1/2 years, 3 1/2 years, and 13 months. Continuous observation following cessation of therapy revealed clinical and biochemical euthyroidism in the children. Thyroid scanning during the neonatal period in the first child failed to identify functional thyroid tissue, suggesting thyroid agenesis, whereas thyroid scan performed on subsequent follow-up revealed a normal gland. Sequential serum measurements of autoantibodies directed towards the thyrotropin receptor were made in the mother and third child by a cAMP bioassay. High titres (five-six fold above normal) of blocking antibodies (tested by measuring the inhibition of TSH-stimulated cAMP production of cultured human thyroid cells by serum immunoglobulin preparations) were present in the mother and newborn 10 days after birth. The levels remained persistently high in the mother, whereas they declined and were undetectable in the child at four months. Thyroid-stimulating immunoglobulin was absent in both mother and child. The data are compatible with transient neonatal hypothyroidism caused by transplacental transfer of antibodies which block thyroid response to TSH. The half-life of the maternally-derived blocking antibody in the infant was estimated as 1-2 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Autoantibodies↗
PubMed1989

Determination by ELISA of anti-DNA antibodies in patients with familial Mediterranean fever.

Positive titers of antibodies against double-stranded (ds) and single-stranded (ss) DNA were found in the sera of 4 and 6 patients, respectively, of 18 who had familial Mediterranean fever (FMF). While anti-dsDNA antibodies were found only in patients with active disease, there was no correlation between the presence of anti-ssDNA antibodies and disease activity. The antibody titers were lower than those found in patients with active systemic lupus erythematosus. This may be due in part to the fact that all the FMF patients were treated with colchicine.

Adult↗
PubMed1976

Enhancement of DNA synthesis and cAMP content of mouse thymocytes by mediator(s) derived from adherent cells.

Supernatants of adherent mouse peritoneal exudate cells or human mononuclear cells were used as the source of lymphocyte activation factor (LAF). LAF was found to potentiate the effect of mitogens such as PHA and Con A on DNA synthesis by mouse thymocytes. However, LAF also was capable of reducing vigorous thymosyte reactions to Con A. Thus, LAF usually enhanced the effect of PHA on DNA synthesis by BALB/c thymocytes to a relatively greater degree than that of Con A. This change in the ratio of Con A to PHA response of thymocytes suggests that LAF can serve as a regulator of thymocyte DNA synthesis. Moreover, in the presence of LAF, allogeneic thymocytes developed the ability to have bidirectional mixed thymocyte reactions. Exposure to LAF not only improved the ability of parental thymocytes to act as responder cells, but, in addition, led to increased stimulatory activity of F1 thymocytes, presumably by promoting the differentiation of stimulator cells. These indications that LAF affected differentiation were investigated further by studying its effect on the cAMP content of thymocytes. LAF stimulated significant immediate but transient elevations of intracellular cAMP and adenylate cyclase activity in thymocyte membranes. In contrast, the mitogens themselves failed to elevate or to influence the effect of LAF on the content of intracellular cAMP of thymocytes. Furthermore, the potentiating effect of LAF on mitogen-induced thymocyte DNA synthesis at times was enhanced by exogenous cGMP, carbachol, or imidazole. These findings suggest that LAF, through its stimulation of cAMP levels in thymocytes may in turn promote thymocytes to differentiate sufficiently to become competent to proliferative in response to mitogens.

Animals↗
PubMed1976

Reconstitution of T cell function in patients with subacute sclerosing panencephalitis treated with thymus humoral factor.

Two patients with subacute sclerosing panencephalitis (SSPE) showed impairment of cell-mediated immunity, as indicated by a low T cell number, decreased intracellular cyclic AMP levels of peripheral blood lymphocytes, negative graft-vs.-host reaction in vivo, negative skin reactions to common antigens and, in one of the patients, abnormal reactions in migration inhibition factor tests. Since some of the impaired T cell functions in one of the patients were reconstituted in vitro by the administration of thymus humoral factor (THF), a thymic hormone shown in an earlier study to regulate maturation of T lymphocytes in in vitro and in vivo animal models, a course of THF administration was given to both patients in this study. In vitro and in vivo assays, which reflect T cell competence, were performed before and after a daily schedule of THF administration that lasted for 10 days in one patient and 21 days in the other. The results of this preliminary trial suggested that THF was capable of reconstituting the impaired T cell functions in both patients after a short term of treatment. These preliminary results should encourage additional long-term therapeutic trials with THF in SSPE patients with impaired cell-mediated immunity.

Animals↗
PubMed1976

Trypsin-induced increase in intracellular cyclic AMP of lymphocytes.

Trypsin increases intracellular levels of cylic AMP (cAMP) in lymphocytes. The trypsin-induced increase in cAMP is blocked by specific trypsin inhibitors and by high concentrations of different proteins. Several proteolytic enzymes from various sources, including other pancreatic proteases, do not cause an increase in cAMP under the same experimental conditions. Immobilized trypsin induced the same increase in cAMP as does free trypsin. The trypsin-induced rise in cAMP is not due to inhibition of cAMP phosphodiesterase, but consistent activation of adenylate cyclase by trypsin could not be demonstrated. The extent of the trypsin-induced increase in intracellular cAMP correlates with the type of the lymphocyte and with the state of maturity attained by the cells. Transformed lymphocytes and nonlymphoid cells do not react at all.

Animals↗
PubMed1975

Properties of Photosynthetic Mutants Isolated from Euglena gracilis.

Four different photosynthetic mutants of Euglena gracilis were characterized as to their lesions in photosynthetic electron transport. Two were defective around photosystem II: one, in electron transport on the oxidizing side of photosystem II, and the second lacked cytochrome 558. The location of the defect in the third mutant was concluded to be in the carbon fixation cycle, since it could catalyse both photosynthetic electron transport and photophosphorylation. The fourth mutant had a defect in its mechanism of photophosphorylation.

Journal Article↗
PubMed1975

A Method for Producing, Selecting, and Isolating Photosynthetic Mutants of Euglena gracilis.

A method was developed for the isolation of photosynthetic mutants of Euglena gracilis. It consists of the following steps. (a) Incubation of the cells under phototrophic conditions in the presence of 3 (3,4-dichlorophenyl)-1, 1-dimethylurea for 1 week. This step caused a drastic reduction in the number of chloroplasts per cell; (b) mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine; (c) phototrophic growth for a few days to allow for phenotype expression; (d) selection by incubation in the presence of arsenate under phototrophic conditions for 2 days; (e) plating and growth under photoorganotrophic conditions; (f) assay of green colonies for ability to evolve oxygen. About 10% of the green colonies were found to be deficient in their ability to evolve oxygen. In principle the method may prove suitable for the isolation of other types of mutants of Euglena.

Journal Article↗