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Biomedical subjects

E T Lally

Publications and source records attributed to E T Lally.

At least 55 records · Page 3Linked to original sources
PubMed1988

Immunosuppressive properties of Actinobacillus actinomycetemcomitans leukotoxin.

Actinobacillus actinomycetemcomitans produces a leukotoxin that kills human polymorphonuclear cells (PMNs) and monocytes but not lymphocytes. In this study, we examined A. actinomycetemcomitans leukotoxin for its ability to alter human peripheral blood lymphocyte (HPBL) responsiveness. After a 90-min exposure to the leukotoxin, all monocytes were killed and HPBL responsiveness to mitogens and antigens was significantly inhibited. The ability of the leukotoxin to inhibit HPBL responses was not surprising, since monocytes and macrophages are required for many lymphocyte functions. However, we were unable to totally restore HPBL responsiveness when adherent autologous monocytes were added back to cultures of leukotoxin-treated lymphocytes. These studies demonstrate that A. actinomycetemcomitans leukotoxin may also exert nonlethal effects directly on lymphocytes. Furthermore, impaired lymphocyte function did not appear to be the result of indirect effects of products released by dying monocytes. Although it is not clear how A. actinomycetemcomitans acts to cause disease, several investigators have proposed that impaired host defenses may play a pivotal role. Several studies have demonstrated defects in PMN, monocyte, and lymphocyte function in patients with periodontal disease. These findings, along with the data presented in this paper, support the hypothesis that patients who harbor A. actinomycetemcomitans could suffer from local or systemic immune suppression. The effects of this suppression may be to enhance the pathogenicity of A. actinomycetemcomitans itself or that of some other opportunistic organism.

Actinobacillus↗
PubMed1987

Monoclonal antibody and immunogold cytochemical localization of amelogenins in bovine secretory amelogenesis.

Amelogenin enamel-protein epitopes in developing incisors were ultrastructurally localized with high specificity resolution. They formed clumps scattered over the enamel organic matrix between the hydroxyapatite crystals, and were also present over islands of stippled or granular material at the forming surface of the enamel matrix demonstrating that this material consists in part of amelogenin enamel protein. The amounts of amelogenin, as judged by labelling density, were not greater in the stippled or the surface crystal-containing matrix as compared to the enamel matrix up to 50 micron deep. Amelogenins were also localized in the rough endoplasmic reticulum. Golgi apparatus and secretory granules of the ameloblasts, which suggests they are merocrine secretions.

Amelogenesis↗
PubMed1986

Production and characterization of a monoclonal antibody to human type III collagen.

Human type III collagen from placenta was isolated and purified for use as an immunogen. A monoclonal antibody was produced which specifically recognizes epitopes unique to type III collagen. The specificity of the antibody was determined by inhibition ELISA, an immunoblot assay, and by immunoprecipitation. Results indicated that the monoclonal antibody recognized only the alpha 1(III) polypeptide chains and did not crossreact with type I, IV, or V collagen. The monoclonal antibody was also used for immunohistochemical localization of type III collagen in tissue sections of human placenta, bovine spleen, and lymph node. In placenta, both large and small blood vessels showed pronounced staining of the tunica media, which contains largely smooth muscle cells, known to synthesize type III collagen. In contrast, the intimal areas and endothelial cells showed no staining with the antibody. In the placental villi, staining was limited to the villous core, where fine fibrillar structures showed strong staining. In lymph nodes, the capsule and pericapsular adipose cells were surrounded by a covering of type III collagen. Within the parenchyma of the node, staining was localized to a branching, reticular array of fine fibers. In the spleen, staining was pronounced in the capsule, splenic trabeculae, and white pulp, where blood vessel staining was especially prominent. The red pulp and splenic sinuses contain little or no type III collagen. The fine network-like or reticular staining pattern found in the lymph node parenchyma is consistent with the staining pattern of the protein reticulin, and suggests that type III collagen may be closely associated with reticulin in certain tissues. Since the role of type III in tissues is unclear, this reagent will be useful in providing new information in this regard.

Amino Acids↗
PubMed1986

Ultrastructure of sialadenoma papilliferum.

Sialadenoma papilliferum is a rare tumor of salivary gland origin and has been reported in the parotid and minor salivary glands of the oral cavity. This tumor is morphologically similar to the papillary syringoadenoma of the sweat gland. We report the clinical and morphologic features of five cases and review the literature. Ultrastructural examination of case 1 revealed the predominant cell type to be an oncocytic cell. These cells contained numerous mitochondria, exhibited parallel filaments within the cell cytoplasm, and were attached by desmosomes. The neoplastic cells appear to exhibit characteristic features of various cell types of the salivary gland duct apparatus.

Adult↗
PubMed1985

Monoclonal antibodies to different epitopes in amelogenins from fetal bovine teeth recognize high-molecular-weight components.

Enamel proteins were extracted and partitioned into amelogenin and enamelin fractions. Although several attempts were made to raise monoclonal antibodies to each protein fraction, monoclonal antibodies were only obtained against the amelogenin fraction. Six monoclonal antibodies were generated, and these could be classified into three groups recognizing different epitopes by a competitive enzyme-linked immuno-absorbent assay. A model for the arrangement of the epitopes is proposed. In Western-blotting experiments, all six monoclonal antibodies recognized amelogenin components of approx. 45,000 and 60,000 daltons as well as lower molecular-weight components of 10,000 to 30,000. It is proposed that the 45,000 and 60,000 dalton components are precursors of the lower molecular-weight components.

Amelogenin↗
PubMed1985

Monoclonal antibodies to leukotoxin of Actinobacillus actinomycetemcomitans.

Hybridoma cell lines which produce monoclonal antibodies to a leukotoxin from Actinobacillus actinomycetemcomitans were prepared. The monoclonal antibodies were selected for their ability to neutralize the cytotoxic activity of the leukotoxin and recognize the toxin on nitrocellulose blots. The antibodies belonged to either the immunoglobulin G1 (IgG1) or IgG2 subclass and differed in their ability to bind to the leukotoxin on nitrocellulose blots. However, only slight differences in neutralization titers were observed. Use of the monoclonal antibodies revealed that polymyxin B-extracted or osmotic shock-released leukotoxin could be separated into several high-molecular-weight polypeptides by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Immunoblot analysis with the monoclonal antibodies also demonstrated that the leukotoxin was present in eight oral strains of A. actinomycetemcomitans that had been previously classified by a biological assay as leukotoxic. The availability of these monoclonal antibodies should facilitate and expand studies concerning the role of the leukotoxin in the pathogenicity of A. actinomycetemcomitans.

Actinobacillus↗
PubMed1984

Localization of free secretory component in pleomorphic adenomas of minor salivary gland origin.

Secretory component (a glycoprotein) is an antigenically distinct portion of the secretory immunoglobulin A, which has been identified in a number of normal and neoplastic epithelial cells. Localization of secretory component was determined in pleomorphic adenomas of minor salivary gland origin using the four-step peroxidase-antiperoxidase technique. Antiserum that detected only free secretory component (FSC) was used. Staining for secretory component was noted in the epithelium that lined duct-like spaces; but was absent in myoepithelial cells and mucous acini. These findings suggest a role for FSC in evaluating the histogenesis of various salivary gland neoplasms.

Adenoma↗
PubMed1983

Production of a monoclonal antibody to bovine tooth enamel proteins.

Several monoclonal antibodies to bovine enamel proteins were produced using the mouse myeloma system. Each antibody recognized the same two protein bands on gel electrophoresis. The clones were tested in situ and clone 185 localized specifically in the enamel layer. Clones 185 and 121 were shown to recognize different antigenic determinants.

Animals↗
PubMed1982

Acinic cell tumor of the minor salivary glands.

The histologic characteristics and clinical features of six new cases of ACT of the minor salivary glands are reported. These neoplasms accounted for 3.8% of all the minor salivary gland tumors examined by our service. Three cell types were identified: acinar, vacuolated, and intercalated duct-cell. Those cell types were organized in three growth patterns: solid, papillary, and microcystic. Tumor cells were PAS positive both before and after treatment with diastase. Occasionally, they were slightly positive to mucicarmine staining. According to our study, ACT occurs in adult life, apparently without sex preference. Asymptomatic swelling was the most frequent presenting symptom; however, on occasion pain and ill-fitting dentures were reported. Most of the tumors in were described as fixed soft tissue masses, less than 1.5 cm in diameter. No recurrences or metastases were seen in any of the patients for a mean period of four years. Simple surgical removal was the therapeutic measure used in all cases.

Adult↗
PubMed1981

Necrotizing sialometaplasia: literature review and presentation of five cases.

Necrotizing sialometaplasia is a benign, ulcerative, inflammatory process of the minor salivary glands, primarily found in the hard palate. It is often mistaken clinically and histologically for a malignant tumor (that is, mucoepidermoid or squamous cell carcinoma). The lesion heals spontaneously in six to 12 weeks. It occurs primarily in persons between the ages of 40 and 60 and has been reported more frequently in men than women. In necrotizing sialometaplasia the squamous metaplasia and tissue necrosis is confined to the existing ductal and lobular pattern of the salivary glands, a unique characteristic that aids in diagnosis. Five additional cases are presented.

Adolescent↗
PubMed1981

Co-operative cellular interactions in the generation of adoptively-transferred murine IgA responses.

The adoptive transfer system was initially used to document the requirement for co-operation between hapten-primed and carrier-primed lymphocytes in generating secondary IgA antibody responses. Studies employing anti-theta antiserum and complement to deplete T cells showed that carrier-specific theta-bearing cells are required for IgA responses. Furthermore, non-specific T-cell help could be provided by transfer of normal allogeneic spleen cells into irradiated recipients. When limiting numbers of 'educated' thymus cells were added to a constant number of spleen cells, depleted of T cells, IgM responses were not affected while both IgG and IgA antibody responses were shown to be dependent on the numbers of thymus cells injected. These results provide direct evidence for the participation of theta-bearing T lymphocytes in IgA anti-TNP antibody responses and suggest that IgA lymphocyte precursors may be inherently more sensitive than IgM B cells to the regulatory effects of helper T lymphocytes.

Animals↗
PubMed1980

Isoelectric focusing of IgA and IgM in composite acrylamide-agarose gels.

A convenient method for isoelectric focusing of intact polymeric IgA and IgM is described. This technique employed composite gels containing 1.0% acrylamide and 0.75% agarose which exhibited minimal electroendosmotic properties. The spectrotypes obtained with mouse IgA myeloma proteins, a human IgA myeloma and rabbit secretory IgA preparations were compared in three gel systems: 5% acrylamide, 0.8% agarose and the composite gel. With respect to resolution of component bands, the composite gel was superior to the other two systems. Hapten binding studies with MOPC-315 IgA and a rabbit secretory IgA anti-DNP antibody indicated that the focused IgA molecules retained their binding site integrity in the composite gel. The pI ranges obtained with microscale sucrose isoelectric focusing and composite gel system showed good correspondence, with the latter exhibiting enhanced resolution. Studies with MOPC-104E IgM revealed improved resolution in the composite gel when compared to the agarose system. Comparison of pI ranges for IgA and IgM immunoglobulins obtained in the present study with those reported previously suggest that IgA spectrotypes are confined to an acidic pI range (3.4--6.4), whereas IgM spectrotypes are not (4.3--8.8).

Acrylamides↗