Lysis Of Epithelial Cells Research Articles

An AU-rich element in the 3 ′ untranslated region of the C/EBPδ mRNA is important for protein binding during G 0 growth arrest

Posttranscriptional regulation at the level of mRNA stability is becoming increasingly recognized as an important mechanism to control the levels of mRNAs that encode key cell fate determining proteins. Previous work from our laboratory demonstrated that C/EBPδ is a highly unstable mRNA in G 0 growth arrested mammary epithelial cells. In this report we investigated trans-acting factor binding to the C/EBPδ 3 ′-UTR and identified a cis-acting element important for this interaction. RNA electromobility shift assays (REMSAs) demonstrate that the C/EBPδ mRNA 3 ′-UTR binds trans-acting factor(s) present in G 0 growth arrested mammary epithelial cell lysates. This binding was not detected in the presence of lysates from growing cells. UV-binding analysis detected a RNA/protein complex of ∼35 kDa following incubation of the full-length C/EBPδ 3 ′UTR with lysates from G 0 growth arrested mammary epithelial cells. Competition assays indicate that a specific AU-rich region (U1) is necessary for trans-acting factor binding to the C/EBPδ 3 ′-UTR. These studies have identified an AU-rich element located within the C/EBPδ 3 ′-UTR that interacts with a putative G 0 growth arrest-specific trans-acting factor(s), which may regulate C/EBPδ mRNA decay.

Phosphorylation of MAP kinase in corneal epithelial cells during wound healing

Purpose. To investigate the role of mitogen-activated protein kinase (MAPK), such as p44/42 MAPK, p38 MAPK and stress-activated protein kinase (SAPK), in corneal epithelial cells during the wound healing process. Methods. A single non-penetrating incision was produced on rat cornea. Then the corneal wound healing process was observed with an immunocytochemical technique using specific antibodies reacting only with phosphorylated p44/42 MAPK, p38 MAPK or SAPK. Cell lysates of corneal epithelial cells in rabbits stimulated with keratinocyte growth factor (KGF) and hepatocyte growth factor (HGF) were processed for Western blot using antibodies to phosphorylated p44/42 MAPK. Results. Maximum activation of p44/42 MAPK was observed in wing and basal cells at wounded regions in rat cornea at 1 hour after the incision. Activation of p44/42 MAPK was still detected in all basal and wing cells at wounded regions at up to 24 hours when the incisions were completely closed, and then receded to normal intensity after 7 days. Neither p38 MAPK nor SAPK were activated during the wound healing process. Western blot analysis of cultured corneal epithelial cells in rabbits showed phosphorylation of p44/42 MAPK after 30 minutes in response to KGF and HGF, whereas non-activated p44/42 MAPK was ordinarily detected even at the absence of KGF or HGF. Conclusions. These results demonstrate that p44/42 MAPK is activated during the corneal wound healing process and suggest that KGF and HGF play an important role in initiation of cell migration and proliferation in the initial wound healing process by activating p44/42 MAPK.

Chlamydia trachomatis cytotoxicity associated with complete and partial cytotoxin genes.

Chlamydia trachomatis is an obligate intracellular human bacterial pathogen that infects epithelial cells of the eye and genital tract. Infection can result in trachoma, the leading cause of preventable blindness worldwide, and sexually transmitted diseases. A common feature of infection is a chronic damaging inflammatory response for which the molecular pathogenesis is not understood. It has been proposed that chlamydiae have a cytotoxic activity that contributes to this pathology, but a toxin has not been identified. The C. trachomatis genome contains genes that encode proteins with significant homology to large clostridial cytotoxins. Here we show that C. trachomatis makes a replication-independent cytotoxic activity that produces morphological and cytoskeletal changes in epithelial cells that are indistinguishable from those mediated by clostridial toxin B. A mouse chlamydial strain that encodes a full-length cytotoxin caused pronounced cytotoxicity, as did a human strain that has a shorter ORF with homology to only the enzymatically active site of clostridial toxin B. Cytotoxin gene transcripts were detected in chlamydiae-infected cells, and a protein with the expected molecular mass was present in lysates of infected epithelial cells. The protein was present transiently in infected cells during the period of cytotoxicity. Together, these data provide compelling evidence for a chlamydial cytotoxin for epithelial cells and imply that the cytotoxin is present in the elementary body and delivered to host cells very early during infection. We hypothesize that the cytotoxin is a virulence factor that contributes to the pathogenesis of C. trachomatis diseases.

Effect of ABO blood group mismatching on corneal epithelial cells: an in vitro study

AIMTo determine, in vitro, the effects of blood group ABO mismatching on corneal epithelial cells.METHODSCorneal epithelial cell cultures were established from 32 human cadaver donor eyes. Epithelial cells (100 μl...

Chromatofocusing nonporous reversed-phase high-performance liquid chromatography/electrospray ionization time-of-flight mass spectrometry of proteins from human breast cancer whole cell lysates: a novel two-dimensional liquid chromatography/mass spectrometry method.

A novel two-dimensional two-column liquid chromatography/mass spectrometry (LC/MS) technique is described in this work, where chromatofocusing (CF) has been coupled to nonporous reversed-phase (NPS-RP) HPLC to separate proteins from human breast epithelial whole cell lysates. The liquid fractions from NPS-RP-HPLC are readily amenable to direct on-line analysis using electrospray ionization orthogonal acceleration time-of-flight mass spectrometry (ESI-TOFMS). A key advantage of this technique is that proteins can be 'peeled off' in the liquid phase from the CF column according to their isoelectric points (pI) in the first chromatographic separation dimension. The NPS-RP-HPLC column further separates these pI-focused fractions based upon protein hydrophobicity as the second chromatographic dimension. The third dimension involves on-line molecular weight determination using ESI-TOFMS. As a result, this method has the potential to be fully automated. In addition, a 2-D protein map of pI versus molecular weight is generated, which is analogous to a 2-D gel image. Thus, this technique may provide a means to study differential expression of proteins from whole cell lysates.

Effects of juvenile hormone on eggs and adults of the cat flea (Siphonaptera: Pulicidae).

Juvenile hormone III plays a major role in regulating feeding and reproduction in the adult cat flea, Ctenocephalides felis (Bouché). Both blood consumption and egg production increased in a dose-dependent manner up to a maximum at 1,250 ppm when fleas were continuously exposed to concentrations up to 12,500 ppm juvenile hormone. Histological studies demonstrated that juvenile hormone III also stimulated cellular differentiation of salivary gland epithelia, midgut epithelia, and fat body cells, enhancing the ability of the adult flea to digest blood and synthesize vitellogenins for the maturing oocytes. In unfed fleas, exposure of adults to concentrations of > or = 1,000 ppm juvenile hormone III applied to filter paper resulted in membrane lysis and destruction of salivary gland and midgut epithelial cells, fat body cells, and ovarian tissue. Unlike juvenile hormone mimics, which have potent ovicidal effects in fleas, juvenile hormone had little effect in preventing egg hatch; 58% of the eggs laid by fleas treated with 12,500 ppm juvenile hormone III hatched, and a concentration of 30,000 ppm was required to reduce hatch to 2% in untreated eggs exposed to treated filter paper for 2 h. Compared with the juvenile hormone mimic pyriproxyfen, juvenile hormone III was less toxic to fed adult fleas. However, at a concentration of 12,500 ppm, juvenile hormone killed approximately 45% of the adults and caused autolysis and yolk resorption in the developing oocytes. Thus, at high concentrations, juvenile hormone appears to have a pharmacological effect on fleas, which is highly unusual in insects.

Bispecific single-chain antibodies as effective tools for eliminating epithelial cancer cells from human stem cell preparations by redirected cell cytotoxicity.

High-dose chemotherapy (HDC) with autologous bone marrow or peripheral stem cell transplantation is discussed as one option to treat the extensive stage of a variety of tumors. Effective methods to eliminate contaminating tumor cells from human bone marrow or stem cell grafts may improve the outcome of the patients. We investigated 3 recombinant bispecific single-chain antibodies (bscAbs) directed against 17-1A (EpCAM), c-erbB-2 (HER-2/neu) and LeY on the one and CD3 on the other binding site for their ability to induce lysis of epithelial tumor cells by retargeting autochthonous T lymphocytes present in bone marrow mononuclear cells (BMMC) and in peripheral stem cell mononuclear cells (PSMC). The bscAbs showed remarkable specific lysis of different epithelial tumor cell lines with BMMCs as well as with PSMCs as effector cells. Investigation of the alpha 17-1A-alpha CD3 bscAb revealed a significant correlation between the percentage of CD3(+) cells present in the BMMCs and the rate of lysis as well as the absence of detrimental effects on the viability of hematopoietic progenitor cells as determined by colony-forming unit assays (CFUs). Our results indicate that recombinant bispecific single-chain antibodies could be new tools for purging of human bone marrow and peripheral stem cell grafts from contaminating epithelial cancer cells for patients receiving autologous stem cell transplantation after HDC.

E-cadherin-mediated Cell-Cell Attachment Activates Cdc42

E-cadherin is a transmembrane protein that mediates Ca(2+)-dependent cell-cell adhesion. Cdc42, a member of the Rho family of small GTPases, participates in cytoskeletal rearrangement and cell cycle progression. Recent evidence reveals that members of the Rho family modulate E-cadherin function. To further examine the role of Cdc42 in E-cadherin-mediated cell-cell adhesion, we developed an assay for active Cdc42 using the GTPase-binding domain of the Wiskott-Aldrich syndrome protein. Initiation of E-cadherin-mediated cell-cell attachment significantly increased in a time-dependent manner the amount of active Cdc42 in MCF-7 epithelial cell lysates. By contrast, Cdc42 activity was not increased under identical conditions in MCF-7 cells incubated with anti-E-cadherin antibodies nor in MDA-MB-231 (E-cadherin negative) epithelial cells. By fusing the Wiskott-Aldrich syndrome protein/GTPase-binding domain to a green fluorescent protein, activation of endogenous Cdc42 by E-cadherin was demonstrated in live cells. These data indicate that E-cadherin activates Cdc42, demonstrating bi-directional interactions between the Rho- and E-cadherin signaling pathways.

New ELISA for quantitation of human urokinase receptor (CD87) in cancer.

The serine protease urokinase-type plasminogen activator (uPA), its inhibitor (PAI-1), and its receptor (uPAR; CD87) facilitate cancer cell invasion and metastasis. Whereas uPA and PAI-1 antigen levels determined in tumor tissue extracts of breast cancer patients correlate with disease recurrence and overall survival, the prognostic relevance of uPAR is still a matter of debate. We established two new sandwich-type enzyme-linked immunosorbent assay (ELISA) formats (HU/IIIF10-ELISA and HU/HD13-ELISA) using the epitope-defined monoclonal antibody (mAb) IIIF10 or the conformation-dependent mAb HD13.1, a polyclonal chicken antibody (HU277), and recombinant soluble uPAR (CHO-suPAR) as the standard. The lower detection limit of the assays was at 0.16 ng/ml, with a linear dose-response up to 5 ng/ml of uPAR antigen. Both ELISA formats showed good reproducibility and recovery. The intra-assay and the inter-assay variation coefficients were respectively 4.3% and 11.7% (HU/IIIF10-ELISA) and 4.0% and 10.7% (HU/HD13-ELISA). The recovery rate of uPAR in cell lysates spiked with CHO-suPAR was above 82% and 88%, respectively. With these new ELISA formats, uPAR antigen content in breast cancer tissue extracts and tumor cell lysates was determined and compared to a commercially available ELISA (ADI-ELISA). By all of the three uPAR ELISA formats CHO-suPAR and uPAR present in lysates of non-malignant epithelial cells and stimulated monocytes were quantified with similar sensitivity. Interestingly, in breast cancer cell lines of epitheloid origin a higher uPAR antigen content was determined by the HU/IIIF10-ELISA than the HU/HD13- or ADI-ELISA formats. In lysates of fibroblastic breast cancer cell lines similar uPAR values were obtained with the HU/IIIF10- and ADI-ELISA formats, whereas with the HU/HD13-ELISA significantly lower uPAR concentrations were determined. The prognostic relevance of tumor uPAR antigen was evaluated in 199 primary breast cancer patients with a median follow-up of 24 months. uPAR antigen values above the cut-off of 3.33 ng/mg protein as determined by the HU/IIIF10-ELISA were significantly correlated with short disease-free survival (p=0.025). Results obtained by the other two ELISA formats (HU/HD13-ELISA and ADI-ELISA) were not associated with prognosis. Our findings stress the need of well-characterized antibodies, which detect both uPAR of non-malignant and tumor cells, in setting up a uPAR-ELISA useful for assessing breast cancer patient prognosis.

Autologous Lacrimal–Lymphoid Mixed-cell Reactions Induce Dacryoadenitis in Rabbits

Autoimmune dacryoadenitis, such as occurs in Sjögren's syndrome, is a frequent cause of lacrimal insufficiency, which in turn can cause dry eye. Rabbits are used frequently to test ocular therapies. Our goal is to develop a rabbit model of autoimmune dacryoadenitis to identify and test candidate therapies. Our approach arises from the observations that lacrimal gland epithelial cells stimulate proliferation in cultured autologous lymphocyte preparations and that an anti-MHC II antibody blocks this proliferation. The purpose of this study was to determine if injecting this proliferating autologous mixed cell reaction could induce dacryoadenitis in rabbits. After establishing that irradiated lacrimal gland epithelial cells stimulate proliferation in autologous peripheral blood lymphocytes, irradiated cells from a single lacrimal gland were co-cultured with autologous lymphocytes and after 5 days the mixed cell reaction, or components of the reaction, were injected into the contralateral lacrimal gland of the donor rabbit. After 2 weeks, the injected glands were removed and lymphocytic infiltration quantitated using digital image analysis of immunostained histological sections. Injecting an autologous mixed cell reaction of co-cultured irradiated lacrimal gland epithelial cells and lymphocytes reliably induced abundant periductal foci of >200 lymphocytes expressing CD18 and/or a rabbit thymic lymphocyte antigen (RTLA). Injection of medium or autologous lymphocytes alone elicited little response; injections of lymphocytes cultured with lysates of lacrimal gland epithelial cells elicited variable, modest responses. These lysates did not stimulate proliferation in the mixed cell reaction and proliferation was not observed if a porous membrane separated co-cultured lacrimal gland cells and lymphocytes. The results demonstrate that injecting an autologous mixed cell reaction of lacrimal gland epithelial cells and lymphocytes reliably creates a model of autoimmune dacryoadenitis. The relative ineffectiveness of components of the reaction to do the same supports the hypothesis that lacrimal gland epithelial cells trigger or exacerbate lacrimal autoimmune disease by presentation of autoantigens via MHC II. This experimental system can aid efforts to further understand mechanisms of diseases, and to identify and test candidate therapies.

Indocyanine Green Angiography in Fundus flavimaculatus

Purpose: To describe the characteristic findings of fundus flavimaculatus (Stargardt disease) as seen on indocyanine green angiography. Methods: Twelve eyes of 6 consecutive patients with fundus flavimaculatus were studied by fundus color photographs, fluorescein angiography and indocyanine green angiography. Results: Indocyanine green angiography allowed visualization of small, clearly demarcated areas in which hypofluorescence increased over time, leading eventually to a large reticular pattern with small areas of normal-appearing choroid encircled by a well-defined network of hypofluorescent curvilinear lesions. These hypofluorescent flecks were present in all 12 eyes but corresponded only partially to the yellow flecks visible on biomicroscopy of the fundus. The peripapillary area was well preserved on indocyanine green angiography and the periphery did not show any visible abnormalities. Conclusions: The hypofluorescent curvilinear areas visualized on indocyanine green angiography form a reticular pattern that is similar to the polygonal shape of the watershed zones between terminal choroidal arterioles, which supply the choriocapillaris. These dark areas may reflect choriocapillaris defects secondary to lysis of lipofuscin-engorged retinal pigment epithelial cells. The typical lesions of fundus flavimaculatus thus seem to be situated in areas of least vascular supply. Their absence in the peripapillary area, which benefits from anastomotic vascular connections, would support this hypothesis.

Intensified regression of colon cancer liver metastases in mice treated with irinotecan and the immunomodulator JBT 3002.

The authors recently reported that tumoricidal activation of macrophages by a new synthetic bacterial lipopeptide, JBT 3002, can augment chemotherapy-mediated tumor-cell killing. The aim of this study was to identify the mechanism responsible for the destruction of metastatic cells. Three daily oral doses of JBT 3002 before once-weekly intraperitoneal injections of 100 mg/kg irinotecan for 3 weeks significantly increased the eradication of established CT-26 murine colon cancer liver metastases compared with treatment with irinotecan alone. Immunohistochemical analyses revealed that the hepatic metastases in mice given combination therapy contained infiltrating CD8+ lymphocytes and a dense infiltrate of macrophages expressing both inducible nitric oxide synthase (iNOS) and interleukin-15. In vitro treatment of peritoneal macrophages with JBT 3002 plus interferon-gamma induced the expression of iNOS and the production of nitric oxide. In the presence of a low (subtoxic) dose of irinotecan, these activated macrophages produced significant lysis of CT-26 cells. The high level of cytotoxicity was inhibited by the specific inducible nitric oxide synthase inhibitor, NG-methyl-L-arginine. In contrast, irinotecan-mediated lysis of normal intestinal epithelial IEC-6 cells was not increased by activated macrophages. Scanning electron microscopy revealed that activated macrophages bound to CT-26 tumor cells but not to normal IEC-6 cells, confirming that nitric oxide-mediated cytotoxicity is specific for tumor cells. Collectively, the results suggest that augmentation of the therapeutic efficacy of irinotecan against colon cancer liver metastases by immunomodulation with JBT 3002 may be associated with elevated inducible nitric oxide synthase and endogenous interleukin-15 in tumor-infiltrating macrophages.

Pathogenesis of abnormal vaginal bacterial flora

Objective: This study was undertaken to determine the relationships between microscopy findings on wet mounts, such as lactobacillary grade or vaginal leukocytosis, and results of vaginal culture, lactate and succinate content of the vagina, and levels of selected cytokines. Study Design: In a population of 631 unselected women seeking treatment at an obstetrics and gynecology outpatient clinic, vaginal fluid was obtained by wooden Ayre spatula for wet mounting and pH measurement, by high vaginal swab for culture, and by standardized vaginal rinsing with 2 mL 0.9% sodium chloride solution for measurements of lactate, succinate, interleukin 1β, interleukin 8, leukemia inhibitory factor, and interleukin 1 receptor antagonist concentrations. Lactate and succinate levels were measured by gas-liquid chromatography and the cytokine concentrations were measured by specific immunoassays. Both univariate analysis (Student t test, Welch test, χ 2 test, and Fisher exact test) and multivariate regression analysis (Cox analysis) were used. Results: Increasing disturbance of the lactobacillary flora (lactobacillary grades I, IIa, IIb, and III) was highly correlated with the presence of Gardnerella vaginalis, Trichomonas vaginalis, enterococci, group B streptococci, and Escherichia coli. Vaginal pH and interleukin 8 and interleukin 1β concentrations increased linearly with increasing lactobacillary grade, whereas lactate concentrations and the presence of epithelial cell lysis decreased. A similar pattern of associations with increasing leukocyte count was clear, but in addition there was an increase in leukemia inhibitory factor concentration. Multivariate analysis of vaginal leukocytosis, lactobacillary grades, and the presence of positive vaginal culture results showed that interleukin 1β concentration was most closely related to the lactobacillary grade, leukemia inhibitory factor concentration was most closely related to the lactobacillary grade and positive culture results, interleukin 8 concentration was most closely related to positive culture results, and interleukin 1 receptor antagonist concentration was most closely related to vaginal leukocytosis and positive culture results. The concentration ratio of interleukin 1β to interleukin 1 receptor antagonist remained stable, except when vaginal leukocytosis increased. In its most severe form, with >10 leukocytes per epithelial cell present, a decompensation of the vaginal flora with a collapse in interleukin 1β and interleukin 1 receptor antagonist concentrations was seen, but there was a concurrent sharp increase in leukemia inhibitory factor concentration. This pattern was completely different from the course of the cytokine concentrations associated with a lactobacillary grade increase. Conclusion: Both disturbed lactobacillary grade and the presence of increasing vaginal leukocytosis were correlated with lactobacillary substrate (lactate) concentration, pH, and the concentrations of a variety of cytokines. There was a remarkably linear increase in these cytokines as either leukocytosis or lactobacillary grade became more severe. In circumstances in which leukocytosis was extreme, however, interleukin 1β was no longer produced but leukemia inhibitory factor concentrations increased. We speculate that in extreme inflammation the body tries to limit the damage that can be done by exaggerated cytokine production. (Am J Obstet Gynecol 2000;182:872-8.)

The role of activated cytotoxic T cells in inflammatory bowel disease.

The role of cell-mediated cytotoxicity in the pathogenesis of ulcerative colitis and Crohn's disease has been controversial since reports indicating either a decreased, or an increased, activity of cytotoxic T cells in active stages of inflammatory bowel disease exist. Some of these discrepancies may be attributed to the fact that so far mostly peripheral blood lymphocytes rather than intestinal T cells have been examined. To overcome some of these limitations we performed in situ hybridizations for the detection of perforin and granzyme A mRNA expressing cells, i.e. of cytotoxic cells activated in situ, in the affected intestinal mucosa. These studies revealed increased frequencies of activated, cytotoxic T cells in active stages of ulcerative colitis and Crohn's disease. Interestingly, activated perforin mRNA expressing T cells are present both in the CD4 and in the CD8 T cell subsets. In the latter T cell subset up to 60% of the mucosal T cells isolated from the affected sites express perforin mRNA at detectable levels. The elevated frequency of activated cytotoxic cells and their histological distribution also in close proximity to the epithelial cells may thus indicate an important role for cytotoxic cells in the pathogenesis of inflammatory bowel disease since activated cytotoxic T cells may further exacerbate the inflammatory process through the production of pro-inflammatory cytokines such as interferon-gamma or tumor necrosis factor-alpha, but also through the release of pro-inflammatory cytokines and chemokines upon lysis of epithelial cells and the increased influx of luminal antigens at the site of epithelial erosions.

Epithelial invasion and cell lysis by virulent strains of Streptococcus suis is enhanced by the presence of suilysin.

Streptococcus suis is an important pathogen of pigs causing arthritis, pneumonia and meningitis and is an occupational disease of farmers and those in the meat industry. As with other streptococci, both virulent and avirulent strains of S. suis are frequently carried asymptomatically in the tonsillar crypts and nasal cavities. Little is known about the process by which virulent strains cross the mucosal epithelia to generate systemic disease and whether this process requires expression of specific bacterial virulence factors. Although putative virulence factors have been postulated, no specific role in the disease process has yet been demonstrated for these factors. This study is the first demonstration that virulent strains of S. suis both invade and lyse HEp-2 cells, a continuous laryngeal epithelial cell line, and that at least one bacterial virulence factor, suilysin, is involved in this process.

Epithelial invasion and cell lysis by virulent strains of Streptococcus suis is enhanced by the presence of suilysin

Streptococcus suis is an important pathogen of pigs causing arthritis, pneumonia and meningitis and is an occupational disease of farmers and those in the meat industry. As with other streptococci, both virulent and avirulent strains of S. suis are frequently carried asymptomatically in the tonsillar crypts and nasal cavities. Little is known about the process by which virulent strains cross the mucosal epithelia to generate systemic disease and whether this process requires expression of specific bacterial virulence factors. Although putative virulence factors have been postulated, no specific role in the disease process has yet been demonstrated for these factors. This study is the first demonstration that virulent strains of S. suis both invade and lyse HEp-2 cells, a continuous laryngeal epithelial cell line, and that at least one bacterial virulence factor, suilysin, is involved in this process.

Cytotoxic T lyhocytes directed against donor HLA class I antigens on airway epithelial cells are present in bronchoalveolar lavage fluid from lung transplant recipients during acute rejection

Background: The lung epithelium is among the first donor tissues encountered by the lung allograft recipient's immune system. The purpose of this study was to determine whether lung epithelium was recognized by T lymphocytes that are isolated from bronchoalveolar lavage fluid of lung allograft recipients during periods of acute rejection. Methods: Lymphocytes isolated from 45 bronchoalveolar lavage samples (from 41 lung transplant recipients) served as effector cells in standard cell-mediated cytolytic assays with several cell lines as targets: BEAS-2B (an immortalized airway epithelial cell line); B-lymphoblastoid cell lines; and K562 (a natural killer–sensitive cell line). Cytotoxic T-lymphocyte activity of bronchoalveolar lavage lymphocytes was correlated with pathologic status. Results: During acute rejection alone (ie, without concomitant cytomegalovirus infection), mean lysis of the airway epithelial target was significantly greater, compared with during no rejection, when these targets expressed donor-specific HLA class I antigens ( P = .007). Lysis of donor class I–matched B-lymphoblastoid cell line targets during rejection was not significantly different from lysis during no-rejection periods ( P = .18). Mean lysis of K562, a natural killer cell target, did not differ between acute rejection (without concomitant cytomegalovirus infection) and no rejection ( P = .30). During cytomegalovirus infection (without concomitant acute rejection), there was no difference in mean lysis of airway epithelial cells, B-lymphoblastoid cell lines, or K562 targets compared with during no cytomegalovirus infection, whereas during acute rejection, compared with cytomegalovirus infection without rejection, there was a significant increase in mean lysis of the airway epithelial target when it expressed donor-specific HLA antigens ( P = .01). Conclusions: Donor HLA class I–specific cytotoxic T-lymphocyte activity directed at airway epithelial cells was demonstrated in bronchoalveolar lavage lymphocytes from lung transplant recipients. Lysis of these targets was significantly higher during episodes of acute rejection. (J Thorac Cardiovasc Surg 1999; 117:565-71)

Branchial rickettsia-like infection associated with clam Venerupis rhomboides mortality

DAO Diseases of Aquatic Organisms Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials DAO 36:53-60 (1999) - doi:10.3354/dao036053 Branchial rickettsia-like infection associated with clam Venerupis rhomboides mortality Antonio Villalba1,*, María J. Carballal1, Carmen López1, Azucena Cabada2, Laura Corral3, Carlos Azevedo3 1Centro de Investigacións Mariñas, Consellería de Pesca, Marisqueo e Acuicultura, Aptdo. 13, E-36620 Vilanova de Arousa, Spain 2Delegación Comarcal de Riveira, Consellería de Pesca, Marisqueo e Acuicultura, E-15960 Riveira, Spain 3Departamento de Biologia Celular, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, P-4050 Porto, Portugal *E-mail: villalba@cimacoron.org ABSTRACT: A histopathological survey was performed to search for the cause of high mortality of the clam Venerupis rhomboides (Pennant) in exploited beds of the Ensenada de Riveira (Ría de Arousa, Galicia, NW Spain). V. rhomboides from 2 beds affected by high mortality, Airós and Coroso, and a 3rd non-affected bed, Agudos, were sampled in spring and autumn of 1996. In addition, clams of the species Venerupis pullastra, with unnoticeable mortality, were taken from Airós during autumn sampling. According to prevalence, infection intensity and associated histopathological signs, a branchial rickettsia-like organism was the only pathogen that could be tentatively blamed for the mortality. Spherical to elongated intracytoplasmic rickettsia-like colonies up to 25 µm in length were observed at the base of gill filaments of the clams. Transmission electron microscopy study permitted identification of the micro-organisms in the colonies as rickettsia-like. Individual prokaryotes measured about 0.5 to 0.8 µm in diameter and up to 3 µm in length. The infection process resulted in extreme hypertrophy and lysis of host epithelial cells. Infection intensity was rated for each clam and comparison among high-mortality-affected and non-affected populations indicated the branchial rickettsia-like infection as the probable cause of the high mortality. KEY WORDS: Venerupis rhomboides · Parasites · Rickettsia-like organisms · Histopathology · Ultrastructure Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in DAO Vol. 36, No. 1. Publication date: April 15, 1999 Print ISSN:0177-5103; Online ISSN:1616-1580 Copyright © 1999 Inter-Research.

The in vitro Propagation of Stunting Syndrome Agent

Stunting syndrome (SS) is a viral enteric disease of turkey poults. The etiologic agent (stunting syndrome agent [SSA]) of this disease has been reported recently. The objective of this study was to develop a method for in vitro propagation of SSA. Primary cells, various continuous cell lines, and embryonated eggs were evaluated. Turkey embryos that were inoculated via the amniotic cavity at 24-25 days of incubation were susceptible to SSA infection. The jejunal maltase activity of SSA-inoculated turkey embryos was significantly (P < or = 0.001) lower than that of control embryos. D-xylose absorption was also altered in SSA-infected turkey embryos. The extent of reduction of D-xylose absorption and maltase activity in the infected embryos was nearly identical to that observed when day-old poults were infected with SSA. The intestines from the infected turkey embryos were pale, thin walled, and distended with fluid. Electron microscopic examination of the intestinal fluid and epithelial cell lysate of infected embryos revealed pleomorphic membraned SSA viral particles. SSA that had been serially passaged in turkey embryos retained its ability to induce SS in day-old poults. All the primary and continuous cells that were evaluated did not support the replication of SSA on the basis of cytopathic effects, electron microscopy, and turkey embryo inoculation. Inoculation of chicken embryos by various routes failed to support SSA. All routes of inoculation, other than the amniotic route at 24-25 days, failed to support SSA in turkey embryos. The results of the this study indicate that the SSA was successfully propagated in turkey embryos that exhibited alterations in embryo intestinal absorption and digestive enzyme activity similar to poults with SS. Successful propagation of SSA in turkey embryos should prove beneficial for future studies including characterization of SSA, prevention and control strategies, and enteric disease modeling.

Taenia solium: Description of the Intestinal Implantation Sites in Experimental Hamster Infections

Experimental infections in golden hamsters with viable Taenia solium metacestodes were used to study by light and electron microscopy the implantation site of the adult tapeworm in the intestinal wall. Implantation sites from 3-, 4-, 10-, and 40-day infections were located in the upper third of the duodenum, excised and fixed in Zenker's or Karnovsky's solution, embedded in Polybed resin, and sectioned longitudinally to observe the position of the worm on the intestinal wall. The scolex of the tapeworm was situated between host villi, with the rostellum penetrating the intestinal wall and the suckers entrapping adjacent villi. Serial sections through several whole implantation sites revealed that the worm was anchored to the host by all 4 suckers simultaneously, each of which was located at a different level and had entrapped intestinal villi in its cavity. Host tissue within the suckers was damaged, exhibiting various degrees of cell lysis and necrosis of epithelial and submucosal cells. The tegumentary surface and microtriches of the scolex were well preserved, with occasional coalescence of tegumentary microvesicles in 10- and 40-day-old infections; microtriches were in direct contact with the damaged host tissue. This study is the first morphological and ultrastructural description of the attachment of T. solium to the intestinal wall employing an experimental model, the results of which may contribute to a better understanding of the biology of human tapeworm infections.