Biomedical subjects
Publications and source records attributed to L Mayer.
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Intestinal intraepithelial lymphocytes (iIEL) are primarily CD8 cells and most of them have a CD28- phenotype, the phenotype of effector cytotoxic T cells. We asked whether the predominance of CD8+CD28- T cells in the gut may result from peripheral blood T cells preferentially migrating to the iIEL compartment and adhering to iEC. Compared with CD4 cells, adhesion of resting CD8+ T cells to iEC cell lines was significantly higher. Adhesion could be blocked with a MoAb to gp180, a molecule expressed on iEC which is known to interact with CD8/lck. No significant difference in the level of adhesion was observed between CD8+CD28+ and CD8+CD28- T cells. Thus CD8 cells may preferentially migrate to the iIEL compartment, but loss of CD28 expression could occur in situ after migration. Consistent with this hypothesis, the CD8+CD28- cells became enriched after co-culturing T cells with iEC cell lines and primary iEC. Induction of the CD8+CD28- phenotype in cord blood and adult T cells was observed in co-cultures with iEC and also with mitogens and superantigens. In the latter case, CD28 down-modulation was seen specifically in the Vbeta subset targeted by the superantigen, indicating that loss of CD28 expression is a direct result of T cell receptor (TCR)-mediated stimulation. The combined results suggest that CD8+CD28- T cells are antigen experienced T cells, and that they may have a survival advantage in the presence of gut epithelial cells in vitro. This may contribute to the predominance of CD8+CD28- T cells in the iIEL compartment.
Every day, obstetric providers treat patients experiencing domestic violence. Domestic violence can have both dramatic and subtle impacts on maternal and fetal morbidity and mortality. This article enumerates patient risk factors for and obstetric consequences of domestic violence. It describes adaptations to the assessment and treatment of pregnancy complications occurring in the context of domestic violence and presents behavioral interventions that can be performed within existing obstetric care delivery systems. Behavioral interventions include assessments of a patient's readiness for change and her emotional responses to the violence. Obstetric interventions include an assessment of risk of physical harm to a pregnant woman and her fetus from domestic violence. Interviewing techniques include educating the patient about the effects of abuse and, over time, validating a patient's efforts to change. Reliance on a team approach and use of community resources are emphasized. All of these mechanisms enable obstetric providers to assist pregnant women in taking steps to end the abuse.
We have described a novel macrophage-derived mucin secretagogue (MMS-68) that mediates mucin secretion in colon cancer cell lines and explants of normal and inflammatory bowel disease (IBD) mucosa. We compared MMS-68 induced mucin release with other known intestinal mucin secretagogues in normal colon explants and in the HT-29 colon cancer cell line, and to study the effects of MMS-68 on mucin release from inflamed and uninflamed ulcerative colitis (UC) and Crohn's disease (CD) mucosa. In normal colonic explants and HT-29 cells, each of the secretagogues including, MMS-68-induced mucin release two- to fivefold more than culture medium alone. In HT-29 cells, MMS-68 plus leukotriene C4 (LTC4) induced a 50% increase in mucin release over either secretagogue alone, and MMS-68 plus platelet-activating factor (PAF) markedly enhanced mucin release by eightfold over either secretagogue. In colonic explants from patients with UC and CD, the mucin release in response to MMS-68 was similar to that of normal colonic explants. Likewise, in isolated epithelial cells from CD and UC (whether involved or uninvolved), MMS-68-induced release was similar to that of epithelial cells isolated from normal colonic mucosa. The number of MMS-68-producing macrophages was lower in uninflamed UC mucosa compared with inflamed UC mucosa and CD mucosa. The mucin secretagogue activity of MMS-68 is comparable to that of other known secretagogues, and PAF can have a synergistic effect on this activity. Whole tissue explants and isolated colonic epithelial cells from patients with IBD respond at least as well as their normal counterparts to MMS-68. MMS-68 may play a role in mucin secretion in normal and inflamed colonic tissue.
The recognition that immune responses in the intestine differ from those seen systemically has led to a search for novel pathways involved in mucosal immunoregulation. One cell type that has surfaced as a prime candidate for such a regulatory role is the intestinal epithelial cell. A number of laboratories have documented that intestinal epithelial cells sample luminal antigens and process and present these to primed T cells. However, several unique features have emerged, making their potential role as antigen-presenting cells a critical part of mucosal homeostasis.
Increasing recognition of the neurologic aspects of depressive disorder has aroused new interest in the potential neuropathologic significance of "psychomotor" symptoms in depression. Psychomotor symptoms have yet to be clearly defined, however. The Motor Agitation and Retardation Scale (MARS) was developed to provide a comprehensive and nonredundant measure of the motor abnormalities associated with agitation and retardation in depression. Forty-one depressed in patients and 20 normal control subjects were assessed. In this sample, the MARS provided a reliable and valid scale for the clinical assessment of 19 abnormal motor behaviors associated with agitation and retardation in depression. The MARS may be useful for investigation of the pathophysiologic significance of various manifestations of motor abnormalities in depression and, as part of a larger battery, for the investigation of the relative contribution of motor abnormalities to psychomotor impairment in depression.
Levels of anti-benzo[a]pyrene diol-epoxide DNA adducts were analysed by high-pressure liquid chromatography/fluorimetric detection in non-tumorous lung tissues from 20 lung cancer patients and in white blood cells from 20 polycyclic aromatic hydrocarbon exposed coke oven workers. All were current tobacco smokers. CYP1A1 mutations (MspI at 6235 nt, Ile-Val462) and GSTM1 deletion polymorphisms in each individual were analysed in genomic DNA by PCR/restriction fragment length polymorphism. Independently of the CYP1A1 genotype (1) all 23 samples in the two groups with non-detectable adducts (< 0.2 per 10(8) nt) were of GSTM1 active genotype; (2) the 17 samples with detectable adducts (> or = 0.2 per 10(8) nt) in the two groups were GSTM1*0/*0. The difference in adduct levels between GSTM1*0/*0 and GSTM1 active genotype was highly significant (p < 0.00005). Among GSTM1-deficient individuals (n = 17), a subgroup of 14 individuals with CYP1A1*1/*1 (wild-type, n = 7) or heterozygous genotype (*1/*2A or *1/*2B, n = 7) showed low levels of BPDE DNA-adducts (range: 0.2-1.3 per 10(8) nt). (3) Three individuals with the rare combination CYP1A1*2A/*2A or *2A/*B and GSTM1*0/*0 showed significantly higher adduct levels (median: 17.4 adducts/10(8) nt, range 1.9-44; p = 0.017). Therefore, combination of homozygous mutated CYP1A1 and GSTM1*0/*0 genotypes lead, at a similar or even lower smoking dose, to a stronger increase of anti-benzo[a]pyrene diol-epoxide DNA adduct levels than found in individuals with CYP1A1 and GSTM1 wild-type. These data provide a mechanistic understanding of epidemiological studies that correlated these 'at risk' genotypes with increased smoking-related lung cancers.
Previous studies support a role for intestinal epithelial cells (IEC) as antigen-presenting cells in mucosal immune responses. T cells activated by IEC are CD8+, suppressor in function, and dependent upon CD8-associated p56lck activation. A 180-kD glycoprotein (gp180) recognized by mAbs B9 and L12 has been identified and shown to be important in CD8+ T cell activation by IEC. Since IEC derived from patients with inflammatory bowel disease (IBD) are incapable of activating CD8+ T cells, we asked whether this correlated with gp180 expression. While frozen sections of normal bowel revealed bright gp180 staining on all IEC, both inflamed and uninflamed ulcerative colitis (UC) specimens showed patchy staining. In Crohn's disease (CD), staining was faint to absent. Flow cytometry confirmed immunohistochemical data. The staining patterns correlated with the ability of IEC to activate CD8-associated p56lck. Normal IEC induced phosphorylation of p56lck in CD8alpha but not CD4+ transfectants. In contrast, both UC and CD IEC activated CD4 and, to a much lesser extent, CD8-associated p56lck. Thus, gp180 expression by IBD IEC appears to be altered, and correlates with a functional alteration of lck activation. This defect may reflect a more proximal event in the pathogenesis of IBD.
BACKGROUND: Studies in animals and an open-label trial have suggested a role for antibodies to tumor necrosis factor alpha, specifically chimeric monoclonal antibody cA2, in the treatment of Crohn's disease. METHODS: We conducted a 12-week multicenter, double-blind, placebo-controlled trial of cA2 in 108 patients with moderate-to-severe Crohn's disease that was resistant to treatment. All had scores on the Crohn's Disease Activity Index between 220 and 400 (scores can range from 0 to about 600, with higher scores indicating more severe illness). Patients were randomly assigned to receive a single two-hour intravenous infusion of either placebo or cA2 in a dose of 5 mg per kilogram of body weight, 10 mg per kilogram, or 20 mg per kilogram. Clinical response, the primary end point, was defined as a reduction of 70 or more points in the score on the Crohn's Disease Activity Index at four weeks that was not accompanied by a change in any concomitant medications. RESULTS: At four weeks, 81 percent of the patients given 5 mg of cA2 per kilogram (22 of 27 patients), 50 percent of those given 10 mg of cA2 per kilogram (14 of 28), and 64 percent of those given 20 mg of cA2 per kilogram (18 of 28) had had a clinical response, as compared with 17 percent of patients in the placebo group (4 of 24) (p<0.001 for the comparison of the cA2 group as a whole with placebo). Thirty-three percent of the patients given cA2 went into remission (defined as a score below 150 on the Crohn's Disease Activity Index), as compared with 4 percent of the patients given placebo (P=0.005). At 12 weeks, 41 percent of the cA2-treated patients (34 of 83) had had a clinical response, as compared with 12 percent of the patients in the placebo group (3 of 25) (P=0.008). The rates of adverse effects were similar in the groups. CONCLUSIONS: A single infusion of cA2 was an effective short-term treatment in many patients with moderate-to-severe, treatment-resistant Crohn's disease.
Previous studies have shown that normal human intestinal epithelial cells stimulate CD8(+) suppressor T cell proliferation in an allogeneic mixed epithelial/T cell co-culture system, which is neither restricted by class I or class II major histocompatibility complex antigens nor by any soluble factors from epithelial cells. Two epithelial specific monoclonal antibodies (mAb), mAb B9 and mAb L12, are potent inhibitors of this mixed epithelial/T cell reaction but not of conventional mixed lymphocyte reactions. While phenotypically distinct by tissue staining, both mAbs recognize a 180-kDa epithelial membrane glycoprotein (gp180). Further characterization of gp180 revealed the following. 1) The protein migrated between 150 and 180 kDa in SDS-polyacrylamide gel electrophoresis and could be resolved by Western blot using mAb B9 or mAb L12. 2) The molecule has two forms, an apically sorted glycosylphosphatidylinositol-anchored form and a basolateral transmembrane form. 3) gp180 is heavily N-glycosylated, since N-glycanase treatment results in a >50% reduction in size. 4) Purified gp180 can bind to peripheral blood T cells and activate p56(lck). 5) gp180 can activate p56(lck) in 3G8 (a murine T cell hybridoma transfected with human CD8alpha cDNA) but not in 3G4 (CD4 transfectant), suggesting that gp180 binds to CD8. Thus, gp180 appears to be a novel regulator of mucosal immune responses.
The nuclear factor kappaB (NF-kappaB) regulates the transcription of genes bearing the kappaB consensus motif. Transmigration of NF-kappaB from the cytoplasm to the nucleus is regulated by the IkappaB family of inhibitory NF-kappaB-binding proteins. Dissociation of the NF-kappaB-IkappaB complex requires both phosphorylation and degradation of IkappaBs. We demonstrate that IL-1beta induces complete IkappaB alpha degradation in Caco-2 cell lines but not in HT-29, T84, SW-480 transformed cell lines, or native colonic epithelial cells. A similar lack of IkappaB alpha degradation in HT-29 cells followed TNF-alpha and bacterial polymer stimulation. IL-1beta stimulated NF-kappaB nuclear translocation and NF-kappaB-dependent IL-1beta and IL-8 expression in both Caco-2 and HT-29 cells as assayed by electrophoretic mobility shift assay, immunofluorescence, kappaB-luciferase transfection, reverse transcriptase-PCR analysis and ELISA. In HT-29 cells stimulated with IL-1beta, IkappaB alpha was phosphorylated and when cycloheximide blocked new protein synthesis, IkappaB alpha was partially degraded. NF-kappaB cytoplasmic to nuclear transmigration was incomplete and preceded IkappaB alpha degradation in 9T-29 cells, in contrast to complete coordinated NF-kappaB nuclear translocation and IkappaB alpha degradation in Caco-2 cells. Greater sensitivity of HT-29 cells to a calpain inhibitor, as measured by IL-8 secretion, suggested enhanced resistance to IkappaB alpha proteolysis. These data show that IL-1beta induces NF-kappaB activity and expression of NF-kappaB-dependent genes in colonic epithelial cells and suggest altered regulation of IkappaB alpha degradation compared with other cell lineages, which may result in their increased responsiveness to therapeutic blockade.
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The purpose of this study was to evaluate the diblock copolymer poly(DL-lactide)-block-methoxy polyethylene glycol as an i.v. delivery vehicle for paclitaxel. Nude mice were implanted s.c. with fragments of MV-522 lung carcinomas and treated with paclitaxel on a daily x 5 schedule when tumors were approximately 5 x 5 mm in size. Cremophor paclitaxel or polymeric micellar paclitaxel were given i.p. or i.v. at the maximum tolerated dose (Cremophor paclitaxel MTD: 20 mg/kg/day i.v. or i.p.; micellar paclitaxel MTD: 25 mg/kg/day i.v. or 100 mg/kg/day i.p.). The tumors were measured using callipers during the experiment and accurately weighted at the end. Two biodistribution studies were carried out. In one study, the nude mice were given micellar paclitaxel at a dose of 25 mg/kg i.v. or 100 mg/kg i.p. in another study, BDF-1 mice were given either micellar paclitaxel or Cremophor paclitaxel at a dose of 20 mg/kg i.v. The mice were sacrificed after a given time and the organs were harvested. Paclitaxel in the organs was extracted with acetonitrile and analyzed using HPLC. Tumor growth inhibitions of 98.5 and 98.7% were obtained from i.v. administered micellar paclitaxel and Cremophor paclitaxel at their MTDs, respectively. Micellar paclitaxel was more efficacious i.p. (98.7% tumor growth inhibition) than Cremophor paclitaxel i.p. (83.0% tumor growth inhibition) at their MTDs. The highest concentrations of paclitaxel were found in the liver after administration of paclitaxel formulations. Paclitaxel was also found in spleen, kidney, lung and blood, in order of decreasing concentration. The preliminary results indicate that polymeric micellar paclitaxel could be a clinically useful chemotherapeutic formulation.
An increased interest in mucosal immunity has stemmed from the identification of novel T-cell populations and developments in oral vaccines and oral tolerance. The development of physiological inflammation is antigen driven. Upon recognition of antigen, the lamina propria (LP) is populated with lymphocytes and activated peripheral cells acquire the capacity to home to the gut. Antigen entry to the gut is via follicle-associated epithelium or M cells. The antigen now interacts with macrophages or CD4+ cells, and go on to the Peyer's patch where B cells undergo a transforming growth factor beta (TGF-beta)-mediated isotope switch to immunoglobulin (Ig) A. TGF-beta may also play a role in the development of oral tolerance. The intestinal epithelium is seen as the site for the activation of CD8+ suppressor cells. Controlled inflammation is therefore explained by the interaction of LP lymphocytes and intra-epithelial cells (IEC). IECs are capable of extending processes that express regulatory surface molecules coupled with antigen processed from luminal uptake. CD8+ T-cell activation is favoured over CD4+ T-cell activation due to the size of the antigenic binding peptide. The result is suppressed inflammation. Other antigen-presenting cells (APCs) and dendritic cells may also contribute to local immunosuppression.
Previous studies have shown that human airway epithelial cells (AEC) can stimulate allogeneic peripheral blood T-lymphocyte (PBT) proliferation. We now sought to determine which AEC surface molecule/T-cell coreceptors are involved in this process. AEC-induced PBT proliferation was inhibited by 25 microM genestein or herbamycin A (0.9 and 1.8 microM), both tyrosine kinase inhibitors. Anti-phosphotyrosine immunoblots performed on PBT lysates after coculture with AEC demonstrated phosphorylation of 56kD and 60kD bands. To determine whether CD3 associated p59fyn, or CD4 and CD8 associated p56lck phosphotyrosine kinases (PTK) were involved, we assayed kinase activity in lymphocyte lysates immunoprecipitated with anti-p56lck and p59fyn mAbs. PBT cells or murine T-cell line transfectants expressing human CD4 (3G4) or human CD8alpha (3G8) were cocultured with AEC or A549, an alveolar-like cell line lacking class II Ag expression. After A549 or AEC coculture, p56lck activity in PB T-cells peaked at 2 min whereas p59fyn kinase activity continued to rise at 8 min. AEC (expressing class II Ags) stimulate PTK activity in both 3G8 and 3G4 cells. A549 stimulated p56lck in 3G8, but not in 3G4 cells. This activation of p56lck was not blocked by preincubation of A549 with anti-class I or anti-CD1d mAbs. An antibody generated in our laboratory, which recognizes an epithelial specific surface molecule (mAb L12) and which blocks AEC driven PBT proliferation, was shown to block PTK activity of peripheral blood T-cell lysates, though not of 3G8 lysates. These studies suggest that AEC are capable of stimulating CD4 and CD8 associated lck and CD3 associated fyn kinases through class II dependent and independent pathways.
Because the gastrointestinal tract is the largest lymphoid organ in the body, it is not surprising that patients with immunodeficiency would present with pathological conditions in the intestine. Several studies have documented a high prevalence of inflammatory, malignant, and infectious gastrointestinal (GI) disorders in patients with common variable immunodeficiency or immunoglobulin A (IgA) deficiency. Interestingly, it has become increasingly apparent that antibody deficiency alone does not result in GI disease. Rather, defects in cellular immunity appear to predispose to a sprue-like disorder, pernicious anemia, giardiasis, nodular lymphoid hyperplasia, and even inflammatory bowel disease. In patients with unusual inflammatory GI disorders, measurement of serum immunoglobulins should be obtained.
Despite the wealth of epidemiological studies that have evaluated the oral health status of older Canadian dental patients, comprehensive epidemiologic data on their medical status, functional status and drug utilization patterns are deficient. To address this deficiency, the authors evaluated 170 older dental patients (> or = 65 years, mean = 82 years, sex distribution = 77.1 per cent female, 22.9 per cent male) in Winnipeg, Manitoba. Study participants averaged five medical conditions per person (males = females). The most prevalent conditions were vision deficits, cardiovascular disorders and orthopedic problems. Functional assessment of the Activities of Daily Living revealed that study participants were essentially independent. Within the study population, 90 per cent were taking at least one medication (mean = 2.8 drugs per person), most of which were analgesics, diuretics and gastrointestinal agents. Drug utilization rates were consistent with other studies that have evaluated prescribing patterns in community-dwelling older Canadian adults.