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Biomedical subjects

R L Wilder

Publications and source records attributed to R L Wilder.

At least 91 records · Page 5Linked to original sources
PubMed1995

Corticotropin releasing hormone in colonic mucosa in patients with ulcerative colitis.

Corticotropin releasing hormone (CRH) is a key hormone in integrated response to stress, acting as the major regulator of the hypothalamic-pituitary-adrenal axis. Recently, local production of CRH has been detected in normal human colonic enterochromaffin cells. CRH is locally secreted in granulomatous and arthritic tissues in rats and humans, where it seems to act as a local proinflammatory agent. To find out if CRH is present in colonic tissues of patients with ulcerative colitis, this study examined the expression of this peptide in the large bowel of patients with ulcerative colitis. Colonic tissues of patients with ulcerative colitis obtained by endoscopic biopsy were immunostained with anti-CRH antibody. CRH messenger (m) RNA was also examined in biopsy specimens of ulcerative colitis by the reverse transcribed polymerase chain reaction method and by in situ hybridisation. Considerably enhanced expression of immunoreactive CRH was found in mucosal inflammatory cells. Intense staining with anti-CRH antibody was also shown in mucosal macrophages. CRH mRNA was expressed in mucosal epithelial cells. The expression of immunoreactive CRH in colonic mucosal epithelial cells of ulcerative colitis slightly increased, but not significantly, compared with normal colonic mucosal epithelial cells. These results suggest that CRH may play a part in the modulation of intestinal immune and inflammatory system, and as a modulator in the pathogenesis of ulcerative colitis.

Adult↗
PubMed1995

Neuroendocrine-immune system interactions and autoimmunity.

The concept of an integrated bidirectionally regulated neuroendocrine-immune adaptive response to stress has strong experimental support. The quality and intensity of this coordinated response to stress varies depending upon age, gender, reproductive status, and other genetically determined factors as well as the types and magnitudes of environmental challenges. These factors and dysfunctional communication between the nervous, endocrine, and immune systems appear to contribute to the development of autoimmune diseases in the Lewis and BB rats, the OS chicken, and the NOD, MRL, NZB, NZW, and NZB/NZW F1 mice. Neuroendocrine-immune dysfunction also contributes to the pathogenesis of human autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, thyroid diseases, and others. This review highlights these concepts. It includes discussions on various aspects of the stress response, the hypothalamic-pituitary-adrenal and -gonadal axes, corticotropin releasing hormone, luteinizing hormone releasing hormone, interleukin-1 and -6, corticosteroids, estrogens, testosterone, dehydroepiandrosterone, growth hormone, prolactin, and thyroid hormone. The role of the nervous and endocrine systems in regulating thymopoiesis and T cell development is also emphasized.

Animals↗
PubMed1995

Genetic map of eight microsatellite markers comprising two linkage groups on rat chromosome 6.

Five genes and three anonymous DNA loci were mapped to rat chromosome 6 by genetic linkage and somatic cell hybrid analyses. The eight loci were all identified by PCR-based microsatellite polymorphism analysis and were characterized in 40 F2 intercross progeny of Fischer (F344/N) and Lewis (LEW/N) inbred rats for segregation analysis. These markers formed two linkage groups spanning, respectively, 58.1 cM and 4.0 cM. The first linkage group is comprised of two anonymous DNA loci and four genes with the following map order and distances: D6Cep8 (previously D3)-17.9 cM-D6Arb309-2.5 cM-Vsnl1 (neural visinin-like protein)-20.4 cM-Prkar2b (type IIb regulatory subunit of cAMP-dependent protein kinase)-8.8 cM-Fkhl1 (forkhead-like transcription factor BF-1)-8.5 cM-Rnu1c (18-3A U1 RNA). The second linkage group is comprised of one gene, Ckb (creatine kinase, brain) and one anonymous DNA locus, D6Arb54, separated by 4.0 cM. For each marker, two to eight alleles were detected in a panel of 16 inbred rat strains (ACI/N, BN/SsN, BUF/N, DA/Bk1, F344/N, LER/N, LEW/N, LOU/MN, MNR/N, MR/N, SHR/N, SR/Jr, SS/Jr, WBB1/N, WBB2/N, and WKY/N). Comparative mapping information indicated that rat chromosome 6 exhibits syntenic conservation with mouse chromosome 12. Homologs of the rat chromosome 6 loci have been identified on human chromosomes 2, 7, and 14.

Animals↗
PubMed1995

Glucocorticoid and/or glucocorticoid antagonist effects in inflammatory disease-susceptible Lewis rats and inflammatory disease-resistant Fischer rats.

Lewis (LEW/N) and Fischer (F344) rats are inbred strains that respond antithetically to administration of several inflammatory stimuli. Thus, in response to streptococcal cell wall-derived peptidoglycan/polysaccharide, 6-week-old female Lewis rats develop acute and chronic polyarthritis, whereas age- and sex-matched Fischer rats are arthritis-resistant. The susceptibility of Lewis rats to development of chronic severe inflammatory disease has been attributed to their inability to appropriately activate their hypothalamic-pituitary-adrenal axis in response to inflammatory stimuli, leading to a functional glucocorticoid deficiency. To investigate whether the acute neurogenic inflammatory response was also different in the two strains, we studied the air-pouch model of carrageenin-induced neurogenic inflammation in adult male Lewis and Fischer rats. Both the volume and the leukocyte concentration of the inflammatory exudate were significantly higher in Lewis than in Fischer rats, suggesting that the known differences in the handling of chronic inflammation between the two strains pertain to the acute neurogenic type of inflammation as well. To confirm that glucocorticoids play a major role in the differential response of the two strains to this inflammatory stimulus, we administered graded doses of the glucocorticoid agonist dexamethasone or antagonist RU 486 to both strains and examined their responses to concomitantly administered carrageenin. RU 486 increased, whereas dexamethasone decreased, the inflammatory response of Fischer and Lewis rats, respectively, to approach the magnitude of each other's natural response, suggesting that glucocorticoids are involved in this phenomenon as well. To rule out any differences in end-organ sensitivity to glucocorticoids between the two strains, we evaluated dose-response relations of whole body, thymus, spleen, and adrenal weights after 1 week daily administration of graded doses of dexamethasone. We found similar ED50 for both Lewis and Fischer rats. We conclude that the differences in the susceptibility to acute, carrageenin-induced, neurogenic inflammation between the LEW/N and F344 rat strains are similar to those of chronic inflammatory responses in these strains and likewise glucocorticoid-dependent. No apparent major differences exist in the sensitivity of target tissues to exogenous glucocorticoids between Lewis and Fischer rats.

Adrenal Glands↗
PubMed1995

Somatostatin may participate in the antiinflammatory actions of glucocorticoids.

Glucocorticoids are potent antiinflammatory agents. They inhibit leukocyte chemotaxis and vascular permeability and generally suppress the expression of many inflammatory mediators. Recent reports suggested that somatostatin (Sms) had significant immunomodulatory properties in vitro and in vivo. In this study we examined the effects of glucocorticoids on immunoreactive somatostatin expression in aseptic inflammatory sites of Sprague-Dawley rats given carrageenin sc. The progress of the inflammatory reaction was studied over a 7-h period with respect to the volume and cellularity of the exudate and the levels of the inflammatory mediators expressed in the inflammatory site, including immunoreactive substance P (sP), corticotropin-releasing hormone (CRH), and tumor necrosis factor-alpha (TNF alpha). Dexamethasone significantly reduced the volume and cellularity of the inflammatory exudates; in parallel, the levels of immunoreactive sP, CRH, and TNF alpha were significantly suppressed by this glucocorticoid. In contrast, immunoreactive Sms was stimulated by dexamethasone in a time-dependent fashion. These findings suggest another mechanism for suppression of the inflammatory reaction by glucocorticoids via stimulation of local Sms expression, which occurs in parallel to the inhibition of the local inflammatory mediators sP, CRH, and TNF alpha.

Animals↗
PubMed1995

Refractory rheumatoid arthritis. Therapeutic options.

Because rheumatoid arthritis rarely remits, refractory disease is common. Attention should be paid to aggravating comorbid conditions. Pharmacologic options currently available include cyclosporin, high-dose methotrexate, combination second-line agents, and creative use of corticosteroids. The available literature is reviewed in this article and the potential risks and benefits of the various options are discussed.

Adrenal Cortex Hormones↗
PubMed1994

Hypothalamic-pituitary-adrenal axis perturbations in patients with fibromyalgia.

OBJECTIVE: To examine basal and stimulated hypothalamic-pituitary-adrenal (HPA) axis and related hormone levels, including adrenocorticotropin (ACTH), cortisol, arginine vasopressin (AVP), and neuropeptide Y (NPY), in patients with fibromyalgia (FM). METHODS: Basal and ovine corticotropin-releasing hormone (oCRH)-stimulated HPA axis function were assessed in 12 patients with FM and in age- and sex-matched normal subjects. Basal plasma AVP levels and AVP release after postural change were assessed, and plasma NPY levels were measured in the same samples. RESULTS: Patients with FM had low 24-hour urinary free cortisol, but normal peak and elevated trough plasma cortisol levels, compared with normal subjects. The net integrated ACTH response to oCRH in FM was not significantly different from that in normal subjects, but tended toward an exaggerated response. There was a significant decrease in net integrated cortisol response to oCRH in FM patients, indicating adrenal hyporesponsiveness. AVP levels were not significantly different between FM patients and control subjects, but variability was greater among the FM patients. Plasma NPY levels were significantly lower in FM patients than in normal subjects. CONCLUSION: These data support the view that HPA axis function is perturbed in patients with FM. Further study is required to ascertain the cause of HPA axis perturbations and their relationship to symptoms in patients with FM.

Adrenocorticotropic Hormone↗
PubMed1994

A single linkage group comprising 11 polymorphic DNA markers on rat chromosome 3.

Eleven polymorphic DNA markers were mapped to rat Chromosome (Chr) 3 by linkage analysis of F2 progeny of F344/N and LEW/N rat strains. The markers, including seven genes and four anonymous loci, formed a single linkage group covering approximately 112 cM with the following order: Ptgs1 (prostaglandin G/H synthase I)-D3Arb178-Scn2a (sodium channel, type II, alpha-polypeptide)-D3Arb1-Cat (catalase)-Bdnf (brain-derived neurotropic factor)-D3Arb219-D3Arb2-Sus2 (seminal vesicle secretion II protein)-Sdc4 (ryudocan/syndecan4)-Stn1 (statin-like protein). Eight of these markers were analyzed for polymorphisms in 14 additional inbred rat strains. Three to five alleles were detected for each marker, suggesting that they are highly polymorphic and useful for genetic mapping studies with inbred rat strains. Chromosomal syntenic conservation among rats, mice and humans is also discussed.

Alleles↗
PubMed1994

Local secretion of corticotropin-releasing hormone by enterochromaffin cells in human colon.

BACKGROUND/AIMS: Corticotropin-releasing hormone (CRH) is a regulator of the hypothalamic-pituitary-adrenal axis and a coordinator of the gastrointestinal response to stress. In addition to its central effects, CRH has peripheral effects on the immune system. CRH is present in several human tissues, such as the brain, spinal cord, adrenal medulla, lung, liver, peripheral blood leukocytes, as well as the gastrointestinal tract. The current study examined the local production of CRH in the normal human colon. METHODS: Normal human colonic tissues obtained by endoscopic biopsy were immunostained with anti-CRH and anti-5-hydroxytryptamine antibody and analyzed for CRH messenger (m)RNA by a reverse-transcribed polymerase chain reaction method and by in situ hybridization. RESULTS: Immunoreactive CRH and CRH mRNA were detected in the colonic mucosal cells in the neighborhood of the base of the crypts. The mucosal cells that expressed CRH mRNA also immunostained with anti-5-hydroxytryptamine antibody. CONCLUSIONS: Normal human colonic mucosal enterochromaffin cells produce CRH. CRH in the colonic mucosa may play a role in the modulation of the intestinal immune system and/or other gastrointestinal functions basally during stressful conditions.

Adolescent↗
PubMed1994

Hypothesis for retroviral causation of rheumatoid arthritis.

Over the past year, convincing direct evidence that rheumatoid arthritis is caused by a retrovirus has not been presented. Strong support for this hypothesis, however, comes from an impressive body of recent work demonstrating that human T-cell lymphotropic virus type I causes a destructive arthropathy that has many of the same features as rheumatoid arthritis. Additional strong support for the hypothesis is provided by the resemblance of the arthropathies induced by caprine arthritis encephalitis and the ovine maedi-visna viruses to rheumatoid arthritis. These retroviral infections emphasize the potential complexity of detecting retroviral involvement and proving its importance in the causation of rheumatoid arthritis. Retroviruses clearly possess diverse pathways for involvement in autoimmune diseases.

AIDS-Related Opportunistic Infections↗
PubMed1994

Simple sequence repeat length polymorphisms mapped to rat chromosome 11.

Two genes and two anonymous DNA loci were mapped to rat chromosome 11 using F2 intercross progeny of Fischer (F344/N) and Lewis (LEW/N) inbred rats. These four loci formed a single linkage group covering 21.5 cM with the following map order: somatostatin (SST)-D11N161-D11N18-cell surface protein (MOX2). These four loci were typed by PCR-based simple sequence repeat (SSR) length polymorphism detection. For each marker four to seven different alleles were detected using a panel of 13 inbred rat strains (F344/N, LEW/N, BN/SsN, BUF/N, LER/N, MR/N, MNR/N, LOU/MN, ACI/N, WBB1/N, WBB2/N, SHR/N, WKY/N). Comparative gene mapping analysis suggests syntenic conservation between rat chromosome 11 and mouse Chromosome 16.

Alleles↗
PubMed1994

Nine polymorphic markers characterized by polymerase chain reaction techniques form two linkage groups on rat chromosome 8.

Five genes and four anonymous polymorphic markers, forming two linkage groups, were mapped in F2 intercross progeny of F344/N x LEW/N rats using polymerase chain reaction (PCR) techniques. Both linkage groups were assigned to rat chromosome 8 because they contained genetic loci previously mapped to this chromosome. The first group was comprised of markers for three anonymous loci and two gene loci, thymus cell antigen-1 (Thy1) and tropoelastin (Eln). The second group was comprised of markers for one anonymous locus and three gene loci, cellular retinol binding protein II (Rbp2), matrin F/G (Matr1), and acyl-peptide hydrolase (Apeh). Seven markers (identified by simple sequence repeat associated length polymorphisms) were characterized in an additional 13 inbred rat strains (ACI/N, BN/SsN, BUF/N, LER/N, LOU/MN, MNR/N, MR/N, SHR/N, SR/Jr, SS/Jr, WBB1/N, WBB2/N, and WKY/N). Two to six alleles were detected for each marker. The reported markers should facilitate genetic mapping and monitoring of inbred rat strains.

Alleles↗
PubMed1994

Cyclooxygenase-1 and -2 expression in rheumatoid synovial tissues. Effects of interleukin-1 beta, phorbol ester, and corticosteroids.

High levels of immunoreactive cyclooxygenase (Cox; prostaglandin H synthase) are present in synovia from patients with rheumatoid arthritis (RA). We now show that the recently identified inducible isoform of Cox, Cox-2, is expressed in synovia from patients with RA. To further explore modulation of the Cox isoforms in RA synovial tissues, we examined the expression and modulation of Cox-1 and -2 in rheumatoid synovial explant cultures and cultured rheumatoid synovial fibroblast-like cells (synoviocytes). Immunoprecipitation of in vitro labeled proteins and Western blot analysis demonstrated the presence of both Cox-1 and -2 under basal conditions in freshly explanted rheumatoid synovial tissues. De novo synthesis of Cox-2 polypeptide was enhanced by IL-1 beta or PMA, and dramatically suppressed by dexamethasone (dex). Cox-1 expression, under the same conditions, showed only minor variation. Since mRNA for Cox-2 is highly unstable, we examined the regulation of Cox-2 transcripts in cultured rheumatoid synoviocytes. Under basal conditions both Cox-1 and -2 mRNAs were present at low levels, but Cox-2 mRNA was markedly increased by treatment with IL-1 beta or PMA. dex markedly suppressed the induction of Cox-2 mRNA. In sharp contrast, Cox-1 transcripts were not modulated by IL-1 beta or dex. These data suggest that modulation of Cox-2 expression by IL-1 beta and corticosteroids may be an important component of the inflammatory process in synovial tissues from patients with RA.

Adrenal Cortex Hormones↗
PubMed1993

Glucocorticoid therapy for immune-mediated diseases: basic and clinical correlates.

Glucocorticoids are pleiotropic hormones that at pharmacologic doses prevent or suppress inflammation and other immunologically mediated processes. At the molecular level, glucocorticoids form complexes with specific receptors that migrate to the nucleus where they interact with selective regulatory sites within DNA; this results in positive and negative modulation of several genes involved in inflammatory and immune responses. At the cellular level, glucocorticoids inhibit the access of leukocytes to inflammatory sites; interfere with the functions of leukocytes, endothelial cells, and fibroblasts; and suppress the production and the effects of humoral factors involved in the inflammatory response. Clinically, several modes of glucocorticoid administration are used, depending on the disease process, the organ involved, and the extent of involvement. High doses of daily glucocorticoids are usually required in patients with severe diseases involving major organs, whereas alternate-day regimens may be used in patients with less aggressive diseases. Intravenous glucocorticoids (pulse therapy) are frequently used to initiate therapy in patients with rapidly progressive, immunologically mediated diseases. The benefits of glucocorticoid therapy can easily be offset by severe side effects; even with the greatest care, side effects may occur. Moreover, for certain complications (for example, infection diathesis, peptic ulcer, osteoporosis, avascular necrosis, and atherosclerosis), other drug toxicities and pathogenic factors overlap with glucocorticoid effects. Minimizing the incidence and severity of glucocorticoid-related side effects requires carefully decreasing the dose; using adjunctive disease-modifying immunosuppressive and anti-inflammatory agents; and taking general preventive measures.

Cells↗
PubMed1993

Tissue-specific regulation of IL-6 production by IL-4. Differential effects of IL-4 on nuclear factor-kappa B activity in monocytes and fibroblasts.

IL-4 inhibits production of certain proinflammatory cytokines, including IL-1 beta, TNF-alpha, and IL-6, by activated monocytes. Although monocytes are a major source of IL-6, other cell types such as fibroblasts and endothelial cells can also express this cytokine. To determine whether IL-4 inhibits IL-6 expression in non-hemopoietic cells, we investigated the effects of IL-4 on IL-6 production in both primary human fibroblasts and fibroblast lines. Rheumatoid synovial fibroblasts were evaluated in these studies because, like monocytes, they produce high levels of IL-6 when stimulated with IL-1. Although peripheral blood monocytes did not constitutively express IL-6 mRNA or protein, stimulation with IL-1 or LPS induced de novo IL-6 expression in these cells. In contrast, synovial fibroblasts displayed a significant basal level of IL-6 production, which was markedly increased after stimulation with IL-1. IL-4 suppressed IL-6 expression in monocytes, but did not inhibit IL-6 production in synovial fibroblasts. The inability of IL-4 to suppress IL-6 synthesis in rheumatoid synovial fibroblasts was not caused by a lack of IL-4R and was not unique to these cells because IL-4 also failed to inhibit IL-6 production in normal fibroblast lines derived from other tissues. Inhibition of IL-6 production by IL-4 in monocytes was associated with decreased nuclear NF-kappa B levels. However, IL-4 does not globally suppress the activity of all DNA-binding proteins because IL-4 treatment did not reduce the levels of NF-IL-6 or NF-IL-1 beta B in the same cells. Because NF-kappa B activation is required for transcription of many cytokine genes, including IL-6, the ability of IL-4 to suppress NF-kappa B activity in monocytes suggests a potential mechanism by which this molecule may inhibit the expression of multiple cytokines.

Base Sequence↗
PubMed1993

Corticotropin-releasing hormone in synovial fluids and tissues of patients with rheumatoid arthritis and osteoarthritis.

Inflammation normally results in enhanced synthesis and secretion of hypothalamic corticotropin-releasing hormone (CRH) which, in turn, exerts antiinflammatory effects by virtue of increased adrenal glucocorticoid production. CRH and CRH binding sites are also expressed in the peripheral nervous and immune systems. Our groups have recently shown that CRH is secreted locally in acute carrageenin-induced inflammation in rats and has predominantly proinflammatory effects. We have also shown that CRH is expressed in the joints of Lewis rats with experimental arthritis. To determine if CRH is present in human inflammatory arthritis, we examined synovial fluids and tissues from patients with rheumatoid arthritis (RA) or osteoarthritis (OA) and normal individuals. We found markedly enhanced expression of immunoreactive CRH in situ in synovium from patients, which was significantly greater in RA than in OA (p < 0.01). CRH concentrations were also significantly higher in RA (140 +/- 33 pg/ml, mean +/- SEM; n = 10) than OA (25 +/- 4 pg/ml; n = 6) synovial fluids (p < 0.005). HPLC showed immunoreactive CRH extracted from RA and OA synovial tissues and fluids coeluted with CRH 1-41. CRH mRNA was present in low levels in synovial tissue from patients with RA and, to a lesser extent, OA. In summary, immunoreactive CRH is locally secreted in the synovium of patients with RA and, at lower levels, OA. These data support the view that CRH functions as an autocrine and/or paracrine mediator of inflammation in humans.

Arthritis, Rheumatoid↗