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At least 217 records · Page 12Linked to original sources
PubMed1978

The effects of trichothecene toxins on the Bursa of Fabricius in day-old chicks.

The effects of T-2 toxin, Fusarenon X (FX), and Nivalenol (NV) on the bursa of Fabricius in the day-old chick were examined. After injections of 5 mg/kg of the mycotoxins into the residual yolk sac, cellular injury was limited at first to the smaller epithelial cells with coarse microvilli, which were located in the central portion of the follicle-associated epithelium. Subsequently necrosis spread out to the periphery. Degeneration and necrosis followed in the lymphoid cells in the lymphoid follicles. The other epithelial components in the follicle were relatively resistant to the mycotoxins. Both FX and NV were less potent than T-2 toxin, although the effects on the bursa of Fabricius were essentially the same. These findings suggest that the follicle-associated epithelium is clearly distinguished from other epithelial components in the bursa of Fabricius in day-old chicks.

Animals↗
PubMed2004

Ovoinhibitor in the chicken bursa of Fabricius: identification, isolation, and localization.

A monoclonal antibody (Mab) developed against a partially purified bursal protein extract was found to bind specifically to a single cell type in the cortico-medullary border region of the chicken bursa of Fabricius. These cells were microscopically similar to the bursal secretory dendritic-like cells. A product with an apparent molecular weight of approximately 56 kDa on SDS-polyacrylamide gel electrophoresis was immunopurified from bursal extracts by utilizing this Mab. This product was subjected to peptide digestion and protein sequencing. The two resulting sequences perfectly matched the known sequence of chicken ovoinhibitor. Gene-specific polymerase chain reaction (PCR) primers were designed for the ovoinhibitor, RNA was purified from chicken bursae, and reverse transcription/PCR was performed. Two amplicons with the expected size for ovoinhibitor mRNA were obtained. These data suggest that the gene for ovoinhibitor is expressed in the bursa of Fabricius, and that the bursal secretory dendritic-like cells may be a previously unreported source of ovoinhibitor.

Amino Acid Sequence↗
PubMed1996

Histochemical and immunohistochemical localisation of nitrergic neuronal and non-neuronal cells in the bursa of Fabricius of the chicken.

The bursa of Fabricius of 24 chickens, 2-4 weeks old, was investigated to determine the distribution of nicotinamide adenine dinucleotide hydrogen phosphate-diaphorase (NADPH-d) staining and nitric oxide synthase (NOS) antigen, by use of NADPH-d histochemistry and NOS immunohistochemistry, respectively. NADPH-d reaction product was localised in neuronal cell bodies and nerve fibres. The stained cell bodies were predominantly in the different bursal compartments; some occurred in the wall and between the lymphoid follicles, and some in the immediate vicinity of blood vessels. Stained nerve fibres travelled mostly with blood vessels, but many were also observed in the connective tissue of the bursa, independent of blood vessels, and some in contact with the lymphoid follicle and interfollicular epithelium. In addition to neuronal profiles, the interfollicular epithelium of the plicae, and the vascular endothelium were densely stained, and lymphocytes were moderately labelled. NOS immunoreactivity was found in neuron-like cells and fibres which were confirmed to be neuronal in adjacent sections stained with antibodies raised against neuron-specific enolase. It was also detected in interfollicular epithelium and lymphocytes but not in vascular endothelium. The distribution patterns of NADPH-d and NOS suggest that nitric oxide (NO) may play a role in the regulation of the secretory activity of interfollicular epithelium and the blood flow through the bursa.

Animals↗
PubMed1984

Defective bursa regeneration after irradiation of young thymectomized chickens.

The ability of the bursa of Fabricius to regenerate after gamma-irradiation and bone marrow reconstitution was examined in chickens thymectomized (TX) immediately after hatching. Irradiation (2 X 500 R) 3 weeks after hatching was followed by impaired bursa regeneration, as judged both by bursa/body weight ratios and by bursa follicle development 3-6 weeks later in TX as compared to control birds. Germinal center formation in the spleen was deficient, and immune responses to sheep erythrocytes (SRBC) and B. abortus (BA) were moderately reduced in the TX as compared to control birds irradiated at 3 weeks but not in TX birds irradiated at 5 weeks of age.

Animals↗
PubMed1996

Muscarinic cholinergic receptor subtypes in the pigeon bursa of Fabricius: a radioligand binding and autoradiographic study.

The pharmacological profile and the anatomical localisation of muscarinic cholinergic receptor subtypes were studied in the pigeon bursa of Fabricius, using radioligand binding and autoradiographic techniques with [3H]quinuclidinyl benzilate (QNB) as a ligand. [3H]QNB was specifically bound to sections of bursa of Fabricius. The binding was time-, temperature- and concentration-dependent. The dissociation constant was 0.31 +/- 0.02 nM, and the maximum density of binding sites averaged 38 +/- 2.5 fmol/mg protein. The pharmacological profile of [3H]QNB binding to sections of pigeon bursa of Fabricius was consistent with the labelling of M2, M3 and M4 muscarinic receptor subtypes. Light microscope autoradiography showed the localisation of [3H]QNB binding sites in the medulla, in follicular septa, in the cortico-medullary border and in lesser amounts in the cortical layer. The functional significance of these receptors should be clarified in future studies.

Animals↗
PubMedDate not supplied

Localization of vasoactive intestinal peptide binding sites in the thymus and bursa of Fabricius of the chick.

The purpose of this study was to determine the distribution of VIP binding sites in the thymus and bursa of Fabricius using receptor binding and autoradiographic techniques. Biochemical characterization of 125I-VIP binding sites determined two classes of specific binding sites in both tissues. The dissociation constants determined in the thymus were 1.12 nM and 88.5 nM, and in the bursa were 0.459 nM and 70.8 nM. Autoradiographic localization of 125I-VIP binding sites within the thymus demonstrated specific binding associated with the medullary region of the thymic lobule and the blood vessels in the interlobular and trabecular areas. Within the bursa of Fabricius, high densities of silver grains corresponded with vascular elements in the interfollicular regions, the epithelial border of the plicae, the muscular layer surrounding the organ, and the diffusely infiltrated area near the burso-cloacal duct.

Animals↗
PubMed1987

Characterization of the estrogen-sensitive cells expressing progesterone receptor in the bursa of Fabricius.

Cells expressing the progesterone receptor (PR) in the bursa of Fabricius (BF) were studied with immunohistochemistry at light-microscopic level, with immunoelectron microscopy (immuno-EM) and with non-specific esterase histochemistry. The antibody (IgG-RB) directed to the B component of the chick oviduct progesterone receptor was shown by immunoblotting to be specific for the PR and to recognize the PR also in the bursa. Two cell types in the BF contain the PR: stromal cells in the interfollicular-subepithelial area and smooth muscle cells lining the BF. The PR was localized in the nuclei of these cells. The bursal epithelium and the cells inside the follicles were not stained for PR. Electron microscopically the immunoreaction precipitate was localized on condensed heterochromatin and on dispersed euchromatin. The cells expressing the PR resembled electron microscopically fibroblasts. Their cytoplasm was rich in rough endoplasmic reticulum indicating active protein synthesis. By non-specific esterase histochemistry we showed that the PR-containing cells were not macrophages, which are morphologically indistinguishable from stromal cells. In the bursae of young untreated chicks the PR was not seen, but was inducible by estradiol treatment and was spontaneously expressed after the onset of sexual maturation. It is concluded that both the stromal fibroblasts and the smooth muscle cells in the BF are estrogen and progesterone sensitive. The expression of PR after the onset of sexual maturation indicates that the BF is directly affected by sexual maturation-associated factors. We suggest that estrogen and progesterone participate in tissue remodelling during bursal involution via the stromal cells and may affect bursal functions via the smooth muscle cells.

Animals↗
PubMed1992

[125I]-labelled iodomelatonin binding sites in the duck bursa of Fabricius: binding characteristics and diurnal variation.

Melatonin receptors in membrane preparations of the duck bursa of Fabricius were studied by using [125I]-labelled iodomelatonin as the radioligand. Specific binding of [125I]-labelled iodomelatonin in the membrane preparations of bursa was stable, saturable, reversible and of high affinity. Scatchard analysis of the specific binding revealed an equilibrium dissociation constant (Kd) of 48.5 +/- 7.4 pmol/l and a total number of binding sites (Bmax) of 1.38 +/- 0.12 fmol/mg protein at mid-light. A diurnal study showed that the Bmax of [125I]-labelled iodomelatonin binding sites at mid-light was 94.4% higher (P < 0.05) than that at mid-dark. There was no significant difference in the mid-light and mid-dark Kd values. The Kd value determined by kinetic analysis was 42.0 +/- 9.3 pmol/l at mid-light. The pharmacological characteristics indicated that [125I]-labelled iodomelatonin binding sites are highly specific for melatonin. Our results suggest that the bursa is a target organ of melatonin action.

Animals↗
PubMed1993

Cystic enlargement of the iliopsoas bursa causing venous obstruction as a complication of total hip arthroplasty. A case report.

The authors report an unusual complication of total hip arthroplasty. A patient developed significant swelling and discomfort in the left lower extremity 4 1/2 years following a left total hip arthroplasty. Magnetic resonance imaging and venography demonstrated a large intrapelvic mass compressing the external iliac vein. An arthrogram revealed a cystic cavity consistent with an iliopsoas bursa in communication with the hip pseudocapsule. Two aspirations of the bursa led to resolution of the cystic enlargement and symptoms. An enlarged iliopsoas bursa should be considered in the differential diagnosis of hip pain or extremity swelling after total hip arthroplasty.

Adult↗
PubMed1991

The neuro-B cell link of peptidergic innervation in the Bursa Fabricii.

The Bursa Fabricii, restricted to birds, specifically provides the microenvironment for B-cell maturation. The presence of nerve fibers containing immunopotent neuropeptides in immune organs opens interesting perspectives on the understanding of neuroimmune communication. As an organ for the development of only B-lymphocytes is not known in mammals, the contribution of a peptidergic innervation to the microenvironment of B-cells is not known. Therefore, we studied the peptidergic innervation of the Bursa Fabricii as an organ of B-cell maturation. Four different neuropeptides were found in nerve fibers of the Bursa Fabricii: tachykinins (TK), vasoactive intestinal peptide (VIP), galanin (GAL), and calcitonin gene-related peptide (CGRP). All these neuropeptides were distributed throughout the different bursal compartments, with the exception of the medulla of the bursal follicles, where the early stages of lymphocyte maturation are found. Double immunofluorescent studies revealed three different fiber populations: One containing coexisting VIP and GAL, the second TK and CGRP, and the last TK and no CGRP. Some of the TK-ir fibers may contain coexisting VIP. As demonstrated by double labeling for neuropeptides and lymphocytes, these heterologous fiber populations were found adjacent to B-cells in the follicle cortex. In addition, VIP-ir fibers were seen in association with macrophages. The origins of the fiber populations and the possible functional implications of our findings are discussed.

Animals↗
PubMed2005

Proinflammatory cytokines and metalloproteases are expressed in the subacromial bursa in patients with rotator cuff disease.

PURPOSE: The pathophysiology of subacromial impingement syndrome is poorly understood. We investigated the expression of inflammatory cytokines, metalloproteases, and the cyclooxygenases in the subacromial bursa in control patients and in patients with rotator cuff tear. TYPE OF STUDY: Basic science evaluation. METHODS: Eighteen patients undergoing shoulder surgery had a subacromial bursa biopsy examination. Patients were divided into 2 groups. Group I (study group) had 10 patients with a full-thickness rotator cuff tear (RCT). Group II (control group) had 8 patients. Seven of 8 underwent shoulder arthroscopy with anterior capsular reconstruction for instability; 1 of 8 underwent open reduction internal fixation for acute proximal humerus fracture. None of the patients in group II had any history of symptoms or signs consistent with subacromial impingement. H&E and immunohistochemical antibody (MMP-1, MMP-9, IL-1, IL-6, TNF-alpha, COX-1, and COX-2) stained specimens were examined by 2 blinded observers using a histologic scale (grade 0 = no staining to grade 4 = intense staining). RESULTS: Histologic evidence of inflammation was present in all patients with RCT (group I). No or mild inflammation was noted in group II. The average staining grade for inflammatory cytokines (IL-1, IL-6, TNF-alpha) and proteinases (MMP-1 and MMP-9) was significantly more pronounced in the RCT group (P < .001). Cyclooxygenase enzymes (COX-1 and COX-2) were also increased in group II (P < .001). CONCLUSIONS: A high level of expression of inflammatory cytokines, proteinases, and cyclooxygenase enzymes, known to produce a catabolic environment, is present in the subacromial bursa of patients with rotator cuff tear. CLINICAL RELEVANCE: These findings support the role of nonsteroidal anti-inflammatory drugs and corticosteroids in RCT treatment, and emphasize the importance of subacromial bursectomy to reduce inflammation in RCT surgery.

Adrenal Cortex Hormones↗
PubMed2006

Antibodies, immunoglobulin genes and the bursa of Fabricius in chicken B cell development.

The bursa of Fabricius is critical for the normal development of B lymphocytes in birds. It is productively colonized during embryonic life by a limited number of B cell precursors that have undergone the immunoglobulin gene rearrangements required for expression of cell surface immunoglobulin. Immunoglobulin gene rearrangement occurs in the absence of terminal deoxynucleotidyl transferase and generates minimal antibody diversity. In addition, observations that immunoglobulin heavy and light chain variable gene rearrangement occur at the same time and that allelic exclusion of immunoglobulin expression is regulated at the level of variable region gene rearrangement provide a striking contrast to rodent and primate models of immunoglobulin gene assembly. Following productive colonization of the bursa, developing B cells undergo rapid proliferation and the immunoglobulin V region genes that generate the specificity of the B cell surface immunoglobulin receptor undergo diversification. Immunoglobulin diversity in birds is generated by somatic gene conversion events in which sequences derived from upstream families of pseudogenes replace homologous sequences in unique and functionally rearranged immunoglobulin heavy and light chain variable region genes. This mechanism is distinct from and much more efficient than mechanisms of antibody diversification seen in rodents and primates. While the bursal microenvironment is not required for immunoglobulin gene rearrangement and expression, it is essential for the generation of antibody diversity by gene conversion. Following hatch, gut derived antigens are taken up by the bursa. While bursal development prior to hatch occurs in the absence of exogenous antigen, chicken B cell development after hatch may therefore be influenced by the presence of environmental antigen. This review focuses on the differences between B cell development in the chicken as compared to rodent and primate models.

Animals↗
PubMed2001

Functional restoration of the bursa of Fabricius following in ovo infectious bursal disease vaccination.

The primary role of the avian bursa of Fabricius is to provide an essential microenvironment for B-lymphocytes to diversify their immunoglobulin genes by gene hyperconversion. Infectious bursal disease (IBD) vaccination using intermediate plus vaccine strains can temporarily deplete the bursal follicles and interrupt the normal B-cell development, which is generally followed by B-cell repopulation and histological regeneration. To find evidence that functional restoration of the bursa of Fabricius occurs in addition to the histological regeneration, we have analysed the chB1 gene expression, which indicates active bursal B-lymphocytes, and also the surface expression of a carbohydrate structure Lewis(x), a marker which identifies those bursal B-lymphocytes that are undergoing gene hyperconversion. In ovo vaccination with an immune complex vaccine (IBDV-BDA) caused transient bursal destruction in both the SPF and the maternally protected broiler groups with differences evident in the starting time, the severity and the duration of the effect. After the depletion phase, signs of histological regeneration appeared together with chB1- and Lewis(x) expression indicating that B-lymphocytes were functionally active and the bursa of Fabricius was serving again as an efficient primary lymphoid organ providing an appropriate microenvironment for B-cell development.

Animals↗
PubMed1998

Progesterone receptor in chicken bursa of Fabricius and thymus: evidence for expression in B-lymphocytes.

In the present work constitutive progesterone receptor (PR) expression in the chicken bursa of Fabricius was detected in the stromal, smooth muscle and follicular medullary cells and smooth muscle cells of blood vessels. PR expression was increased during sexual maturation and after estrogen treatment. Bursal medullary PR-positive cells were further characterized to be B-lymphocytes by flow cytometric analysis. In addition, estrogen induced expression of PR in the bursal FAE-cells (follicle-associated epithelial cells). In the thymus PR was expressed constitutively in the connective tissue cells of the capsule and interfollicular septa, in a few medullary cells and in vascular smooth muscle. The PR-positive medullary cells consisted of epithelial cells, large polygonal cells resembling macrophages and plasma cells. T-lymphocytes were PR-negative. Estrogen up-regulated PR expression in the thymus. Immunoblotting studies revealed that both isoforms of PR, i.e. PR-A and PR-B, were expressed in the bursa of Fabricius and thymus with PR-B dominance. These results suggest that the chicken primary lymphoid organs bursa and thymus are under regulation of estrogen and progesterone. Expression of PR in B-lymphocytes, macrophages and plasma cells in the chicken is documented for the first time and suggests evidence for direct action of progesterone on immune responses.

Animals↗
PubMedDate not supplied

Sensory nerve supply in the human subacromial bursa.

The subacromial bursa is the major component of the subacromial gliding mechanism. The neural elements of the subacromial bursa obtained from specimens that underwent autopsy and surgery were investigated by the silver impregnation and immunohistochemical methods with antisera to substance P and calcitonin gene-related peptide; which are considered to be involved in nociceptive transmission, and protein gene product 9.5. Free nerve endings, Ruffini endings, Pacinian corpuscles, and two kinds of unclassified nerve endings were observed. Most of these receptors were observed of the roof side of the coracoacromial arch, which is exposed to stress because of the impingement. A delta and C fibers, thought to be nerve fibers of free nerve endings, were immunoreactive to substance P and calcitonin gene-related peptide. On the other hand, thick fibers thought to originate in encapsulated mechanoreceptors were not immunoreactive to substance P. The subacromial bursa receives nociceptive stimuli and proprioception and seems to regulate appropriate shoulder movement.

Adult↗
PubMed1982

[A bursa of the tendon of the flexor hallucis longus (author's transl)].

The author reports six cases in whom there was contrast filling of a bursa related to the tendon of the flexor hallucis longus during the course of an arthrogram. All patients had had joint symptoms for a prolonged period; in three patients there was osteochondritis dissecans. Possible mechanism for the development of the bursa is discussed. The hypothesis is proposed that the bursa results from increased pressure in the joint due to recurrent synovitis.

Adult↗
PubMed1975

Origin of hemopoietic stem cells in embryonic bursa of Fabricius and bone marrow studied through interspecific chimeras.

The histogenesis of the bursa of Fabricius and of bone marrow was studied by a biological cell marking technique based on differences in the nuclear structure of two species of birds, Japanese quail (Coturnix coturnix japonica) and chick (Gallus gallus). In quail cells the nucleus contains a large amount of heterochromatin associated with the nucleolus. That makes it possible to distinguish them from chick cells after Feulgen-Rossenbeck staining and by electron microscopy. By grafting bursal rudiments and limb buds of quail into chick and inversely it was possible to demonstrate that the whole hemopoietic population of the bursa of Fabricius and of bone marrow is derived from bloodborne extrinsic stem cells. Neither endoderm nor mesoderm of the bursal rudiments is capable of differentiating into lymphoid cells. Combinations of quail bursal endoderm with chick homologous mesenchyme showed that the reticular cells of the follicles are the only endodermal derivatives of the bursa. The mesenchymal bursal component gives rise to the interfollicular connective cells. The contribution to bone marrow histogenesis of cells of vascular and blood origin, on one hand, and of the elements of the cartilaginous model, on the other hand, was analyzed. It appeared that osteoblasts, osteocytes, and stromal cells of marrow are derived from the perichondrium. In contrast, the endothelium of the vascular buds and the hemopoietic cells which invade the diaphysal cartilage during the endochondral ossification process do not belong to the mesenchymal bone primordium but have a fully extrinsic origin.

Animals↗
PubMed1986

Rearrangement of chicken immunoglobulin genes is not an ongoing process in the embryonic bursa of Fabricius.

We report a molecular analysis of the chicken Ig loci in single bursal follicles from 3- to 7-week-old chickens. Each follicle contained between 10(5) and 3 X 10(5) cells. The Ig gene rearrangement patterns obtained were compared to the pattern observed with the corresponding total bursal DNA. The results obtained for the light chain locus imply that a very small number (two on average) of rearrangement events takes place in each follicle. For the heavy chain locus similar results were obtained, each follicle showing a more restricted pattern than the total bursa. These data favor a model in which each follicle is colonized by a very few prebursal stem cells that are committed to a particular Ig gene rearrangement at the very beginning of the development of the embryonic bursa. The role of the bursa as the organ in which such a committed stem cell population for the B-cell lineage arises is discussed.

Animals↗