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Biomedical subjects

F Shanahan

Publications and source records attributed to F Shanahan.

At least 199 records · Page 11Linked to original sources
PubMed1991

Pathways of activation of the Epstein-Barr virus productive cycle.

The promoter for the 2.8-kb RNA of Epstein-Barr virus encoding BZLF1 and BRLF1 was identified and shown to be activated by both BZLF1 and BRLF1 but not by 12-O-tetradecanoylphorbol-13-acetate. Site-directed mutagenesis suggests that two binding sites for BZLF1 within the promoter contribute to the transactivation by BZLF1. The early kinetics of induction of the 2.8- and 1.0-kb RNAs encoding BZLF1 and BRLF1 in Akata cells treated with anti-immunoglobulin indicate that both RNAs appear within 60 min. The results indicate some likely pathways of activation of Epstein-Barr virus productive cycle gene expression.

Base Sequence↗
PubMed1991

Differentiation-associated expression of the Epstein-Barr virus BZLF1 transactivator protein in oral hairy leukoplakia.

The BZLF1 protein of Epstein-Barr virus (EBV) is a key immediate-early protein which has been shown to disrupt virus latency in EBV-infected B cells. We have generated a monoclonal antibody, BZ1, to BZLF1 which reacts in immunohistology, immunoblotting, and immunoprecipitation and which recognizes both the active, dimeric form and the inactive, monomeric form of the protein. Biopsies of oral hairy leukoplakia, an AIDS-associated lesion characterized by high-level EBV replication, were examined by immunohistochemistry using the BZ1 monoclonal antibody. A differentiation-associated pattern of BZLF1 expression was observed, BZ1 reacting with nuclei of the upper spinous layer of the lesion. This finding suggests that the BZLF1 promoter may be regulated by the degree of squamous differentiation. A comparison of in situ hybridization to EBV DNA and viral capsid antigen staining with BZ1 reactivity suggested that BZLF1 expression precedes rampant virus replication. The inability to detect EBV in the lower epithelial layers of oral hairy leukoplakia raises questions concerning the nature of EBV latency and persistence in stratified squamous epithelium.

Antibodies, Monoclonal↗
PubMed1991

Development of a biotinylated analog of substance P for use as a receptor probe.

The development of a biotinylated substance P (SP) analog for use as a receptor probe is reported. The lysine in position 3 of SP was substituted by arginine and an amino terminal extension (NTE-SP) was added consisting of Lys-Tyr-Gly-Gly-Gly-Gly-Gly-Gly. Biotinylation of the N-terminal lysine was performed. The biotinylated peptide was purified by high performance liquid chromatography and characterized by mass spectral analysis. Binding studies using human IM-9 lymphoblasts with the biotinylated SP analog (biotin-NTE[Arg3]SP) and native SP yielded dissociation curves which were identical. In addition, the biotinylated SP analog retained functional activity similar to that of native SP in altering intracellular calcium concentration of Fura-2 loaded isolated rabbit colonic myocytes. Applicability of the SP receptor probe was demonstrated by using the streptavidin-peroxidase detection system to identify SP receptors on human IM-9 lymphoblasts. In conclusion, a biotinylated SP analog has been developed which retains the functional characteristics of the native peptide and is a useful and versatile probe for receptor studies.

Amino Acid Sequence↗
PubMed1991

Neutrophil cytoplasmic antibodies: a link between primary sclerosing cholangitis and ulcerative colitis.

Whether serum autoantibodies to neutrophil cytoplasmic components, previously found in ulcerative colitis, are also associated with primary sclerosing cholangitis was determined. In an enzyme-linked immunosorbent assay for immunoglobulin G neutrophil antibodies, neutrophil binding by primary sclerosing cholangitis sera was significantly greater than that for primary biliary cirrhosis, chronic hepatitis B, and chronic non-A, non-B hepatitis. Similar differences were seen when sera from patients with primary sclerosing cholangitis without evidence for ulcerative colitis were compared with sera from liver disease controls. Perinuclear immunofluorescence staining of neutrophils was exhibited by the majority of ulcerative colitis, primary sclerosing cholangitis, and primary sclerosing cholangitis without ulcerative colitis sera. The combination of elevated immunoglobulin G neutrophil antibodies and a perinuclear pattern was 65% sensitive and 100% specific for primary sclerosing cholangitis compared with the liver disease control sera. It is concluded that neutrophil cytoplasmic antibodies in ulcerative colitis and primary sclerosing cholangitis may be markers of shared underlying immunopathogenic mechanisms. Identification of the target antigen(s) may facilitate understanding of the underlying immune response and development of an improved disease marker assay.

Autoantibodies↗
PubMed1990

A distinct subset of antineutrophil cytoplasmic antibodies is associated with inflammatory bowel disease.

Antineutrophil cytoplasmic antibodies (ANCAs) have recently been demonstrated to be of importance in Wegener's granulomatosis and certain other forms of vasculitis associated with glomerulonephritis. With a fixed-cell ELISA, we demonstrated that ANCAs occur in the serum of patients with inflammatory bowel disease (IBD) involving the colon. In a blinded study, sera from 21 of 25 patients with ulcerative colitis (UC) and five of 25 patients with Crohn's disease had binding in the fixed-cell ELISA. The five reactive sera from patients with Crohn's disease were associated with the presence of clear colonic involvement. The presence of ANCA in patients with UC was not influenced by disease distribution or activity. Indeed, such antibodies were present in four subjects with UC more than 5 years after colectomy. The IBD-associated ANCAs were distinct from ANCAs reported in patients with Wegener's granulomatosis since the pattern of staining on indirect immunofluorescence exhibited a nongranular perinuclear distribution (P-ANCA). The P-ANCA observed in IBD did not react with myeloperoxidase and thus was distinct from the P-ANCA observed in vasculitis with cresentric glomerulonephritis. IBD and, in particular, UC, is associated with a distinct subset of P-ANCA, which may have important diagnostic and potential pathophysiologic implications.

Adult↗
PubMed1990

The CD8+ Leu-7+ subset of T cells in Crohn's disease: distinction between cytotoxic and covert suppressor functions.

An expanded T cell subpopulation (CD8+ Leu-7+) has previously been reported in the peripheral blood of patients with Crohn's disease. This subpopulation of T cells was associated with a 'covert suppressor' function, particularly in patients with mild/early Crohn's disease, suppressing immunoglobulin production in vitro when cultured in the presence of pokeweed mitogen. T cells with the same CD8+ Leu-7+ phenotype have also been shown to exhibit non-major histocompatability complex-restricted cytotoxicity when triggered by anti-CD3 antibodies, and this cytotoxic activity has also been shown to be elevated in patients with Crohn's disease. Because cytotoxic cells can have immunoregulatory properties, we investigated the possible relationship between the cytotoxic and 'covert suppressor' functions of the CD8+ Leu-7+ subset of T lymphocytes in patients with mildly active Crohn's disease. Although the correlation between T cell cytotoxic activity and the CD8+ Leu-7+ cells was confirmed, no evidence for covert suppressor activity was found; there were no significant differences between the amount of IgM secreted by B cells from normal subjects and patients with Crohn's disease when cultured with T cells at increasing T:B ratios. In addition, IgM production by peripheral blood B cells did not correlate with either the number of CD8+ Leu-7+ cells or with the level of cytotoxic T cell activity. Furthermore, when B cells and CD4+ T cells were co-cultured with increasing numbers of CD8+ T cells, there was no evidence for excessive suppressor T cell activity in Crohn's disease. Although some patients exhibited low levels of IgM production, this was due to diminished B cell function, rather than excessive T suppressor activity or defective T helper activity. We conclude that the CD8+ Leu-7+ T cell subset is associated with cytotoxic but not with enhanced or covert suppressor activity in Crohn's disease. The previously described covert suppressor function attributed to cells with this phenotype in Crohn's disease was not found to account for diminished B cell responsiveness in vitro and is unlikely to be of major pathophysiologic significance in the majority of patients.

Antigens, Differentiation↗
PubMed1990

Albinism and Hermansky-Pudlak syndrome in Puerto Rico.

Five types of oculocutaneous albinism and two types of ocular albinism were found among 349 Puerto Rican albinos. The most prevalent type of albinism was the Hermansky-Pudlak syndrome (HPS). HPS was observed in five of every six albinos in Puerto Rico. The prevalence of HPS was highest in the northwestern quarter of the island, affecting approximately one in 1,800 persons, and approximately one in 22 are carriers of the gene. HPS is an autosomal recessively inherited triad of a tyrosinase-positive type of albinism, a hemorrhagic diathesis due to storage pool deficient platelets and accumulation of ceroid in tissues. The pigmentary phenotype of HPS albinos resembled that of any other type of oculocutaneous or ocular albinism. The most reliable method of diagnosing HPS is by a deficiency of platelet dense bodies observed by electron microscopy. The accumulation of ceroid in the tissues is associated with fibrotic restrictive lung disease and granulomatous enteropathic disease. The enteropathic disorder resembles Crohn's disease and with few exceptions, had its onset after 13 years of age. The major causes of death were fibrotic restrictive pulmonary disease, hemorrhagic episodes and sequelae of granulomatous enteropathic disease. Menometrorrhagia was common in women with HPS. No immune deficiency was found in HPS patients. The majority of patients with HPS had visual acuities of 20/200 or worse and consequently were legally blind. Albinos of all types, including HPS, lacked binocular vision due to nearly complete crossing of the optic tracts.

Albinism, Ocular↗
PubMed1989

Enhanced peripheral blood T-cell cytotoxicity in inflammatory bowel disease.

Monoclonal antibodies to the CD3 component of the T-cell antigen receptor can trigger antigen-specific cytotoxic T cells to elicit nonantigen-specific cytotoxicity, possibly by mimicking or bypassing the requirement for antigen triggering. We have used this technique to investigate the possible presence of in vivo primed cytotoxic T cells, of unknown antigen specificity, in peripheral blood of patients with inflammatory bowel disease. Peripheral blood lymphocytes, which were depleted of background natural killer (NK) activity (CD16-), from patients with Crohn's disease exhibited significantly enhanced levels of anti-CD3-triggered T-cell cytotoxicity compared with lymphocytes from normal subjects. Enhanced lytic activity was also found in some patients with ulcerative colitis and in patients with ulcerative colitis postcolectomy. These results were not influenced by treatment or disease activity. There was no correlation between the anti-CD3-triggered T lytic activity and the NK activity in normal subjects or in patients with inflammatory bowel disease. The surface antigen phenotype of the anti-CD3-triggered T killer cell was CD3+, CD8+, CD16-, and Leu 7+. The results provide indirect evidence for increased activity of a subpopulation of cytotoxic T cells, of unknown antigen specificity, in inflammatory bowel disease. Increased activity in patients with ulcerative colitis postcolectomy suggests that this might reflect a fundamental immunological disturbance.

Antibodies, Monoclonal↗
PubMed1989

Increased neutrophil receptors for and response to the proinflammatory bacterial peptide formyl-methionyl-leucyl-phenylalanine in Crohn's disease.

Neutrophils have an important role in mediating tissue injury in inflammatory bowel disease. The proinflammatory peptide formyl-methionyl-leucyl-phenylalanine (FMLP), which is produced by intestinal bacteria, is a potent chemotactic factor for human neutrophils and has been used experimentally to induce acute colitis in animal models. Its action involves specific receptors on the surface of the neutrophil. Increased mucosal permeability, which has been described in Crohn's disease, might contribute to the pathogenesis of the intestinal lesions in this disease by means of increased absorption of FMLP and other gut-derived bacterial products. To evaluate the interaction between FMLP and neutrophils in patients with inflammatory bowel disease, we have studied the binding characteristics and responsiveness of circulating neutrophils to this peptide. Neutrophils from patients with Crohn's disease but not those with ulcerative colitis were found to have significantly increased numbers of receptors for FMLP with similar affinity constants. This was associated with a significantly increased functional response to FMLP in chemiluminescence assays. Differences in neutrophils between Crohn's disease and ulcerative colitis are probably not intrinsic to the neutrophil but reflect their conditioning by the different inflammatory milieu of these diseases.

Adult↗
PubMed1989

Lack of an association between polymorphisms of the T-cell receptor alpha-chain and ulcerative colitis.

It was recently reported that, using a T-cell receptor alpha-chain complementary deoxyribonucleic acid probe (pGA5) and the restriction enzyme Eco RV, a 10-kilobase restriction fragment length polymorphism was detected significantly more frequently in patients with ulcerative colitis than in patients with Crohn's disease and controls. This finding had great potential importance, as no gene marker had previously been found to be strongly associated with inflammatory bowel disease. Therefore, an attempt to confirm it in an independent laboratory and patient population has been made in this study. Thirty patients with ulcerative colitis, 30 with Crohn's disease, and 30 healthy control subjects were studied using the Eco RV restriction enzyme and the same T-cell receptor alpha-chain complementary deoxyribonucleic acid probe as was used in the prior report. No 10-kilobase fragment or any other polymorphism using this probe-enzyme combination was found in any of the individuals studied. Polymorphisms were observed with the restriction enzyme Bgl II, but their frequencies did not distinguish between cases and controls. Therefore, there is as yet no evidence for an association between polymorphisms of Eco RV-digested genomic DNA probed with the pGA5 T-cell receptor alpha-chain complementary deoxyribonucleic acid and the predisposition to inflammatory bowel disease.

Blotting, Southern↗
PubMed1989

Temporal expression and location of colony-stimulating factor 1 (CSF-1) and its receptor in the female reproductive tract are consistent with CSF-1-regulated placental development.

During pregnancy the mouse uterine epithelial synthesis of the mononuclear phagocyte growth factor designated colony-stimulating factor 1 (CSF-1) is regulated by female sex steroids. To study the role of CSF-1 in the pregnant female reproductive tract, the temporal expression and cellular sites of synthesis of CSF-1 and CSF-1 receptor (CSF-1R) mRNA were determined. CSF-1 mRNA, predominantly the 2.3-kilobase (kb) form, was first detected by in situ hybridization in uterine epithelium prior to implantation on day 3 and subsequently increased, reaching a peak at days 14-15. Its expression was restricted to the uterine epithelium at all stages of gestation and was not localized to areas of implantation. CSF-1R mRNA was first detected in maternal decidua at day 6. It was expressed in the decidua basalis during placentation, after which its expression declined. At day 7.5, trophectodermal cells also expressed CSF-1R mRNA; during placentation, it was found also in the diploid trophoblasts. The high level of CSF-1R mRNA expression by trophoblast giant cells was independent of their location around the conceptus. There was a differential distribution of CSF-1R mRNA expression in the mature placenta, with expression in the giant trophoblastic layer greater than spongiotrophoblastic layer greater than labyrinthine layer until term. Yolk sac cells also expressed low levels of CSF-1R mRNA. The coincidence of uterine CSF-1 mRNA expression and CSF-1 synthesis with both placental growth and CSF-1R mRNA expression in decidual cells and trophoblasts strongly implicates CSF-1 in the regulation of placental growth and differentiation.

Animals↗
PubMed1988

Hidradenitis suppurativa. Glucose tolerance, clinical, microbiologic, and immunologic features and HLA frequencies in 27 patients.

Glucose tolerance, lymphocyte populations, and HLA types were studied in 27 patients with untreated hidradenitis suppurativa; 18 of these patients had a negative history for acne vulgaris. Six patients (22%) had an increased incidence of impaired glucose tolerance. We failed to confirm a previous report of high incidence of flat glucose tolerance curves. The frequency of HLA-A and HLA-B antigen loci and the median values of peripheral blood T lymphocytes were similar to the control population. However, seven patients with moderate or severe clinical disease had a marked reduction in T lymphocytes and these patients had an increased frequency of the HLA antigens, A1 and B8. These results suggest that T lymphocytes may play a role in the pathogenesis of hidradenitis suppurativa and that HLA-A1 and HLA-B8 may predispose the patient to more severe disease, but further research is necessary to clarify this.

Adolescent↗
PubMed1988

Enhanced neutrophil chemiluminescence in familial Mediterranean fever.

Familial Mediterranean Fever is a disorder of unknown cause characterized by recurrent, self-limited paroxysms of serosal inflammation. Although the neutrophil is the predominant cell involved, no cellular abnormalities are known. Chemiluminescence was studied in neutrophils from 20 asymptomatic patients with this disease and 21 healthy controls to evaluate the oxidative response to formyl-methionyl-leucyl-phenylalanine (f-met-leu-phe). In a subset of patients with familial Mediterranean fever, neutrophils but not monocytes were shown to have significantly enhanced chemiluminescence compared to controls. The enhanced responsiveness of neutrophils to f-met-leu-phe in this disease was found to occur at a postreceptor level. Receptor binding assays demonstrated no differences in binding affinity and receptor number between patients and controls. In addition, a similar enhancement in chemiluminescence was observed with an alternative stimulus (zymosan). In contrast to chemiluminescence, chemotaxis induced by f-met-leu-phe was not enhanced in patients with familial Mediterranean fever. The enhanced neutrophil chemiluminescence may identify a subclinical inflammatory state in attack-free patients with familial Mediterranean fever, as enhanced chemiluminescence is also observed in chronic inflammatory diseases with active inflammation.

Chemotaxis, Leukocyte↗
PubMed1988

Neuroendocrine modulation of the immune system. Possible implications for inflammatory bowel disease.

Evidence for neuroendocrine regulation of the immune system is reviewed. This includes human clinical studies of the influence of psychological stress on immune function, direct experimentation in animals, including classical Pavlovian conditioning of the immune response, modulation of immune function in vitro by chemical messengers such as neuropeptides, the finding of receptors for neuropeptides on immunocytes, and the demonstration that lymphoid tissue is directly innervated. Secretory products of the immune system, which include interleukins and neuropeptides, may also influence the neuroendocrine system. Communication between the two systems is therefore bidirectional. The potential importance of the neuropeptide-immunocyte interaction within the intestinal mucosal immune system is emphasized, and its possible relevance in inflammatory disorders is discussed. This aspect of the "gut-brain" interaction deserves further study.

Animals↗
PubMed1988

Role of the CD45 (T-200) molecule in anti-CD3-triggered T cell-mediated cytotoxicity.

NK-depleted human peripheral blood lymphocytes can be modulated with anti-CD3 to kill certain targets during 3-hr cytotoxicity assays. When triggered by anti-CD3 antibody, these effector T cells killed only NK-sensitive targets, such as K562 and HEL 92.1.7, and NK-resistant targets, such as Daudi, whose killing is inhibited by anti-CD45 (T-200) monoclonal antibodies, such as 13.3. NK-sensitive targets, MOLT-4, U266/AF10, Jurkat, and CCFR-CEM, and 10 NK-resistant cell lines, including Raji, IM-9, U698, U937, and GM-1056, whose killing is not inhibited by anti-CD45 monoclonal antibodies, were not killed by alpha-CD3-T effectors, suggesting that the CD45 molecule may be involved in the killing process. Anti-CD3-triggered T cell killing of target cells was inhibited greater than 95% by the monoclonal antibody 13.3. This inhibition of cytotoxicity by 13.3 was not due to competition of this IgG1 antibody for Fc receptor binding site on the target cell, since the IgG1 monoclonal antibody anti-beta 2-microglobulin did not block cytotoxicity. Single cell assays and calcium pulse assays showed that CD45 is involved in a postbinding, pre-calcium-dependent stage, similar to that shown for NK cytotoxicity. There was a relative shift of importance of different epitopes of CD45 in anti-CD3-T cytotoxicity compared to NK cytotoxicity. Anti-CD45 antibodies which bind to the C terminus end of the molecule played a more important role in anti-CD3-T cytotoxicity than NK cytotoxicity. Thus, a subset of T cells exists that exhibits anti-CD3-triggered non-MHC-restricted killing of certain NK-sensitive and NK-resistant targets in association with a CD45 molecule which is functionally different from the NK CD45 molecule.

Antibodies, Monoclonal↗
PubMed1988

Human mucosal T-cell cytotoxicity.

Non-major histocompatibility complex-restricted cytotoxicity triggered by antibodies to the CD3 component of the human T-cell receptor complex is thought to be an indirect measure of in vivo primed cytotoxic T-cell activity. We have used this technique to examine the lytic activity of freshly isolated T cells from noninflamed human colonic mucosa. Anti-CD3-triggered T-cell (anti-CD3-T) cytotoxicity was found in all mucosal specimens studied. The mucosal anti-CD3-T effectors do not have Fc receptors for immunoglobulin G, and are therefore distinct from T gamma cells, which mediate antibody-dependent cellular cytotoxicity. The surface antigen phenotype of mucosal anti-CD3-Ts is CD2+, CD3+, CD8+, CD4-, CD16-, and Leu7-. In contrast, peripheral blood anti-CD3-T effectors are Leu7+. Although non-major histocompatibility complex-restricted, mucosal anti-CD3-T cytotoxicity has considerable target specificity, which differs from that of natural killer and lymphokine-activated killer cells. The profile of target cell susceptibility and the inhibitory effects of anti-CD45 antibody suggest that the CD45 molecule on the effector cell may be an important determinant of anti-CD3-T sensitivity. As anti-CD3-triggered lysis may be a marker of in vivo primed mucosal T cells of undetermined antigen specificity, this technique might have important implications in inflammatory bowel disease, where the antigen(s) inciting the mucosal immune reactivity is not certain.

Antigens, Surface↗