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Biomedical subjects

B Bozhkov

Publications and source records attributed to B Bozhkov.

At least 19 recordsLinked to original sources
PubMed2001

Corrugated waveguides as resonance optical filters--advantages and limitations.

The role of the excitation of guided waves propagating in a corrugated dielectric waveguide is discussed in view of the resonance anomalies in reflectivity. Narrow-wavelength filtering properties that are due to these sharp anomalies have been a topic of interest for some time, but a proper understanding of device performances requires an analysis of tolerances with respect to the incident-beam collimation and to waveguide losses. Such an analysis is proposed in this paper, and the conclusion is that the incident-beam divergence plays a critical role in reducing the maximum reflectivity for narrow-band filters.

Journal Article↗
PubMed1996

[The T-cell receptor--its participation in the pathological immune response].

This work reviews clonal rearrangements of T-cell receptor genes in peripheral T-cells of patients with lymphoproliferative diseases. The role of T-cell genes for predisposition to autoimmune diseases is analysed. Methodological approaches for analysis of T-cell receptor repertoire and autoimmune diseases are presented. The role of T-cell receptor-antigen recognitions in IgE mediated allergic reactions is described.

Antigen-Antibody Reactions↗
PubMed1990

[Endoperoxides and the immunological indices of patients with chronic pyelonephritis].

In 31 patients with chronic active pyelonephritis and 10 clinically healthy controls the following indices were followed up: the serum level of the endoperoxides and several parameters of humoral and cell immunity (T-lymphocytes, active T-lymphocytes, T-helpers, T-suppressors, B-lymphocytes, NK-cells, immunoglobulins G, A and (M), as well as the lysing activity of the natural killers towards the cell line K-562. The patients with chronic pyelonephritis were classified into two groups: I group--patients examined for serum peroxides in the acute phase of the inflammatory process and II group--patients examined in the subacute phase. A statistically significant differences was found for the serum endoperoxides between the patients form the I group (in the acute phase of the disease) and the healthy controls (respectively) 52.0 +/- 17.3 nmol MDA and 9.0 +/- 6.9 nmol MDA, p less than 0.001). The difference between the patients in the subacute phase and the healthy controls was insignificant (p less than 0.1). No significant deviations were found in the immunologic indices studied. The findings show that the immunologic mechanisms probably do not play a leading role in the pathogenesis of chronic pyelonephritis. The endoperoxides level is an index of the activity of inflammatory process in this disease.

Adult↗
PubMed1989

[Changes in the level of urinary secretory immunoglobulin A in patients with recurrent pyelonephritis].

The urine concentration of secretory immunoglobulin A was studied in 58 healthy persons (26 women and 32 men) and in 55 patients (44 women and 11 men) with chronic recurrent pyelonephritis before the beginning of the antibacterial treatment. An immunoenzyme method on a solid phase was used (ELISA). In 21 patients a lowered urine secretory immunoglobulin A level (IgA) was found, in 19 patients it was elevated and in 15 patients it was in normal ranges. In the group of patients with an elevated secretory IgA level the antibacterial treatment was successful in 89.5% of the patients while in the group of patients with a lowered secretory IgA level the treatment was successful only in 61.9% of the patients. In 12 patients the secretory IgA level was examined after the treatment and in 72.7% of them it was changed--in 38.2% of the patients the level was lowered and in 34.5% of the patients it was elevated. The local immune response of the organism against infections is discussed.

Adult↗
PubMed1988

[Beta 2-microglobulin in chronic exacerbated pyelonephritis].

The serum and urine beta 2-microglobulin levels were determined in patients with chronic recurrent pyelonephritis and in healthy controls. The urine beta 2-microglobulin level was considerably increased in the patients with chronic recurrent pyelonephritis which is linked with the activity of the disease.

Adult↗
PubMed1988

[Familial studies of patients with hereditary angioedema].

25 families with 607 members were studied. 165 persons of them suffer from hereditary angioneurotic edema and 28 persons had died from this disease. The clinical forms of the disease are discussed. A classification of angioneurotic edema caused by C-inactivator deficiency is presented. The importance of the examination of C1 inactivator (quantitatively and qualitatively) and of C4 complement fraction in patients with hereditary angioneurotic edema is pointed out.

Adolescent↗
PubMed1986

[Cell-mediated immunity in patients with atopic allergic diseases].

Some parameters of cellular-mediated immunity in patients with atopic bronchial asthma and pollinosis rhinitis were studied. A statistically significant reduction of suppressor and active subpopulation was established as well as of the total fraction T-lymphocytes and a growth in the helper-suppressor ratio. A statistically significant reduction of lymphocytic reactivity to phytohemagglutinins was also established via blasttransformation test as compared with a group of healthy subjects. The results obtained convincingly confirmed a quantitative and functional T-cellular immunodeficiency in atopy. The clinical improvement of the patients with atopic bronchial asthma that were conducted a specific hyposensibilization for over 6 months, was accompanied by increase of T-suppressors and active T-cells and reduction of immuno-regulatory index. Some practical trends in the early diagnosis of immunodeficient state in atopic diseases are discussed.

Adolescent↗
PubMed1984

Anti-DNA antibodies in blood serum of psoriatic patients.

The anti-DNA antibody titer (heat denatured, native and monostranded) was studied in 61 patients with psoriasis and 41 healthy controls. Positive titers of anti-DNA antibodies were established in 19.3% of the psoriatics and in 4.9% of the controls. Antibodies against heat-denatured DNA were discovered in 8.2% of the patients and in 0% of the healthy persons; against native DNA in 18% of the psoriatics and 4.9% of the controls and against monostranded DNA in 31.7% of the psoriasis patients and 9.8% of the control group. In general, the percentage of the positive titers of anti-DNA antibodies in psoriatics was about 4 times higher than that of the healthy controls.

Adult↗
PubMed1984

[Effect of beta-adrenergic mimetics and histamine on the capacity of T-lymphocytes from asthmatic patients and healthy persons to form E-rosettes].

The active and total E-rosettes, according to Wybran et al. method were studied in 30 patients with various forms of bronchial asthma and 6 healthy subjects, and the reactivity of rosette--forming T-lymphocytes was determined after stimulation by asthmopent, histamine and acetylcholine. It was established that the lymphocyte histamine-sensitive adenylatecyclase shows a preserved response in patients with atopic asthma and via the formation of cAMP reduces the percentage of the "active E-EFC, whereas adrenaline-sensitive adenylatecyclase is with reduced activity in the same patients. The latter corresponds to the absence of essential changes in the percentage of E-RFC in the atopic asthmatics. To some of the patients, guanylatecyclase activity was studied prior to and past incubation with acetylcholine or histamine of the lymphocytes, treated not with colchicine, used as performing agent on the microtubular apparatus of the cell. To a group of healthy subjects, colchicine effect was determined at the level of cAMP. Conjugated correlations were established between cAMP and cGMP versus the microtubular apparatus and hence--as regards the rosette-formation.

Acetylcholine↗
PubMed1984

[Serum thyroxine (T4) levels and thyroxine-binding capacity of patients with corticosteroid-dependent and atopic bronchial asthma].

The patients with bronchial asthma, treated a long time with corticosteroid s (the so called cortico-dependent bronchial asthma) are an adequate model for the study on the dependence between the function of the thyroid gland and the effect of glucocorticosteroids. The study was carried out on 12 patients with atopic, 14--with cortico-dependent bronchial asthma and II--healthy subjects. The function of the thyroid gland was assessed by the serum level od thyroxine and thyroxine-binding capacity, determined by immuno-enzyme methods. Erythroid values were established in all three groups of the examined subjects. The stronger inhibition of the thyroid function in the patients with atopic asthma as compared with the cortico-dependent patients is of certain interest, in spite of the fact that the differences are not statistically significant.

Adolescent↗
PubMed1978

[Changes in 3H-noradrenaline activity in the adrenals and serum of rats under the influence of histamine and adrenocorticotropic hormone].

The authors examined the changes in the distribution of 3H-noradrenaline in the adrenal glands and serum of white rats-control and experimental-after administration of histamine and ACTH. The results from the experiments revealed characteristic curves of accumulation of 3H-noradrenaline in the adrenal glands of the examined animals, with maximum at the tenth minute and characteristic changes in the activity of the labeled noradrenaline in the adrenals and serum after administration of histamine and ACTH, followed up to the second hour. On the basis of the obtained results from the radiometric examination and from the follow-up of the level of the blood sugar, the authors make inferences for the sequence and character of the processes of incorporation and release of catecholamine from the adrenal glands under the action of ACTH and histamine.

Adrenal Glands↗