Cytokines, thyroid autoantibody synthesis and thyroid cell survival in culture

In autoimmune thyroid disease lymphoid cells infiltrating the thyroid gland occur in conspicuous aggregates or as a diffusely distributed population invading the thyroid follicles. Consequently cytokines secreted by activated T cells or macrophages could influence neighbouring thyroid cells as well as other lymphocytes. We have investigated this possibility using recombinant cytokines. Thyroid cell survival was assessed in terms of mitochondrial dehydrogenase activity in monolayers exposed to tumour necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), interleukin-1 (IL-1 alpha and beta) and interleukin-2 (IL-2) in the presence or absence of thyroid-stimulating hormone (TSH). Neither TNF-alpha nor IL-2 affected thyroid cell survival, IFN-gamma was usually inhibitory and IL-1 alpha slightly enhanced cell survival in some experiments. However, the effects were small and variable and were not enhanced by potentially synergistic combinations of cytokines, longer periods of exposure, or different culture conditions. In contrast, IFN-gamma, IL-2 and TNF-alpha inhibited the ability of thyroid lymphocytes from patients with Graves' disease and Hashimoto's thyroiditis to synthesize autoantibodies to thyroid peroxidase (TPO) and thyroglobulin (Tg). Comparison of lymphoid populations isolated by digestion and/or mechanical disaggregation indicated that a population of activated B cells, plasma cells and T cells, intimately associated with thyroid cells since they could only be extracted by digestion, was influenced by cytokines. Our studies suggest that in addition to its well-recognized ability to induce MHC class II antigens on thyroid cells, IFN-gamma may inhibit thyroid cell proliferation and TNF-alpha, IFN-gamma and IL-2 may down-regulate thyroid autoantibody synthesis.     

Influence of lectins, hexoses, and neuraminidase on the association of purified elementary bodies of Chlamydia trachomatis UW-31 with HeLa cells.

Using highly purified elementary bodies of Chlamydia trachomatis UW-31 (serotype K), we found that HeLa 229 monolayer cultures bound more 32P-labeled chlamydiae after pretreatment with the lectin wheat germ agglutinin. The lectin, on the other hand, inhibited competitively when chlamydial association was assayed in the presence of polycations. The two effects of wheat germ agglutinin were abolished when N-acetylneuraminic acid (NeuNAc)- or N-acetylglucosamine (GlcNAc)-preincubated wheat germ agglutinin was used. Brief exposure of HeLa cells to neuraminidase abolished the ability to bind the elementary bodies, whether or not polycations were present. Furthermore, at 5 degrees C but not at 37 degrees C, NeuNAc, GlcNAc and N-acetylgalactosamine inhibited chlamydial association only in the absence of the polycation DEAE-dextran. The results suggest that NeuNAc residues on the plasma membrane are the principal, but not the only, receptors for this strain of C. trachomatis.     

Finite element solution of steady state temperature distribution in the human torso

A finite element model of the steady state temperature distribution in the human torso is developed. The torso is approximated by a circular cylinder of core surrounded by a layer of muscle and insulating layers of fat and skin. The model is simplified by neglecting longitudinal heat flow. The region occupied by a circular cross-section of the torso is discretized into a mesh of triangles and the boundary of the torso, that is, the skin surface, is consequently approximated by a polygon. The elliptic partial differential equation governing the steady state temperature distribution, together with the associated boundary conditions, are expressed in equivalent variational form. Linear basis functions are used and the resulting integral is minimized over the region bounded by the approximating polygon. Results for two numerical experiments are determined by solving systems of linear equations.     

Isolation and immunochemical characterization of the group-specific antigen of Streptococcus mutants 6715.

The group d antigen of Streptococcus mutans 6515 was isolated from a buffer (pH 7.3)-boiled extract of whole cells and analyzed immunochemically. Rabbits immunized in three different fashions with whole S. mutans 6715 each responded to the same antigenic cell surface component. This presumptive major antigen was found in culture supernatant, sonically treated supernatant, acid and buffer extracts of whole cells, and trichloroacetic acid extract of cell membranes. A crude preparation of this antigen could completely inhibit antibody-mediated cell (S. mutans 6715) agglutination in a spectrophotometric analysis. The antigen was purified from buffer-boiled extracts by gel filtration on columns of Sepharose 4B. The antigen did not migrate to the anode on electrophoresis nor did it contain appreciable quantities of phosphorus, glycerol, or ribitol. This suggested that the d antigenicity did not reside in a teichoic acid. The d antigen contained galactose and glucose as the sole saccharides, in a ratio of 5.9:1.0. Protein (9.5%) appeared to be a portion of the antigen, although Pronase-digested antigen retained the same electrophoretic mobility and could precipitate virtually all (98.6%) purified antibody directed to the intact antigen. The data obtained from hapten innvolved. Glucose also contributed to the immunodominant region. Antibody directed to the d antigen may be of importance in the inhibition of adherence phenomena manifested by S. mutans organisms of the d group.     

Suppression of primary immunization to the rabbit red cell alloantigen HgA by passively administered anti-HgA

Hg^A-negative rabbits were given an intravenous injection of Hg^A-positive red cells followed within 30 minutes by an intravenous injection of IgG anti-Hg^A. Several weeks later a second injection of Hg^A-positive red cells, without antibody, was given; the survival of these red cells was compared with the survival of red cells given to animals which had received no passive antibody. As judged by a relatively good survival of the second injection of red cells, primary immunization to Hg^A was at least partially suppressed when the dose of anti-Hg^A given with the first injection of red cells was such that 260–750 μg antibody was bound per m1 red cells. In three groups of animals given Hg^A-positive cells and anti-Hg^A in doses such that 20–40 μg antibody was bound per m1 red cells there was apparently no suppression of the antibody response.

It is concluded that the amount of specific IgG antibody required for the suppression of primary immunization is at least ten times greater, in terms of μg antibody per m1 red cells, for the rabbit antigen Hg^A than for the human antigen Rh; the difference may be due partly to the greater number of Hg^A antigen sites on the rabbit red cell compared with the number of Rh(D) sites on the human red cell.

     

Acute inflammatory reaction after myocardial ischemic injury and reperfusion. Development and use of a neutrophil-specific antibody.

Reperfusion of the infarcted canine myocardium after 1 hour of ischemia is associated with an acute inflammatory infiltrate at the border of the infarct. In this paper, we demonstrate that early margination and emigration of neutrophils originate in thin-walled (approximately 5 micrometers) venous cisterns that average 200 micrometers in length and vary from 10 to 70 micrometers in width and show strong constitutive expression of both ICAM-1 and P-selectin; this class of vessels (venous cisterns) appears to be a unique feature in heart. A monoclonal antibody (SG8H6) with specificity for canine neutrophils was developed that allowed much more sensitive immunohistochemical detection of neutrophils in tissue and allowed us to follow tissue infiltration with time. Samples from 1 hour of reperfusion revealed dense margination and substantial emigration of neutrophils associated with the venous cisterns and collecting venules. By 2 hours, there was intense local emigration to the extravascular space between cardiac myocytes. By 3 hours, the infiltrate extended deeper into the infarct, and there was a continuous border zone of neutrophil infiltration that overlapped a region where intact cardiac myocytes strongly expressed ICAM-1 mRNA and extended into the necrotic tissue. At later times, neutrophil migration into infarcted tissue continued to progress. Neutrophil transmigration into reperfused myocardium is more extensive than previously described, and its extravascular distribution during early reperfusion is primarily in the viable border zone of the myocardium where myocyte ICAM-1 mRNA is found. These data are compatible with the hypothesis that extravascular neutrophils may participate in reperfusion injury.     

Montgomery's areolar tubercle. A light microscopic study

Conflicting impressions regarding the anatomy of Montgomery's areolar tubercle exist. Twelve modified radical mastectomy specimens provided 1,536 serial sections of areolar tubercles. In 34 of 35 tubercles (97%), a mammary lactiferous duct was associated with a sebaceous apparatus. This lactiferous duct ascended from deeper mammary parenchyma and entered the sebaceous gland. Histopathologic changes identified included featured of fibrocystic disease, atypical intraductal hyperplasia, and carcinoma in situ. Because the areolar tubercle has two components, a sebaceous gland and a mammary duct arising from deeper breast parenchyma, diseases of the breast may also involve the areola independent of papilla-nipple involvement. Areolar preservation may best be used with the knowledge that diseases underlying the areola may also involve the areola.     

HL-A8 and LD-8a in Patients with Myasthenia Gravis

The frequency of HL-A8 in myasthenia gravis is markedly increased in women (60-80%) but not in men. The MLC determinant, LD-8a, is frequently associated with HL-A8. Of the 37 female MS patients, 15 were LD-8a positive (41%), whereas of the males only one of seven was LD-8a positive. The frequency of HL-A8 was 68% in women and 29% in men with the disease. We therefore conclude that the gene which is responsible for the increased susceptibility to myasthenia gravis in women and which is present in the MHS region, is more closely linked to the SD-2 than to the LD-1 locus.