Effects of early cyclophosphamide treatment on lymphoid organs and its immune response in ducks

Cyclophosphamide treatment of newly hatched White Pekin ducks significantly reduced the weight of their lymphoid organs and almost completely eliminated the formation of bursal lymphoid follicles at one week of age. There after the thymus and spleen of these ducks completely recovered in weight at 7 weeks of age. The bursa, however, retained its light weight and morphological defects, such as the absence of lymphoid follicles. The specific antibody producing-capability to Salmonella pullorum was also eliminated. The total dosage of cyclophosphamide was smaller than that employed in chickens, which makes effective chemical bursectomy in ducks possible.     

Expression of multidrug resistance (mdr) gene(s) in primary lymphoid organs of chicken immune system during embryonic development

The present study investigated the processing of painful electrical stimuli in patients with unilateral frontal or parietal lobe damage and matched control subjects. Patients with frontal lesions showed increased pain thresholds when the stimuli were administered contralateral to the lesion. While the peak-to-peak amplitudes of the N150/P250 components of the somatosensory potentials increased linearly with stimulus intensity in the control subjects, the responses in the frontal group did not change significantly between stimulation at pain and tolerance threshold. There was no evidence for altered pain processing in patients with parietal lobe lesions. The findings of the present study support the hypothesis of an involvement of the frontal cortex in pain perception in humans.     

Fibroblasts as efficient antigen-presenting cells in lymphoid organs

Only so-called "professional" antigen-presenting cells (APCs) of hematopoietic origin are believed capable of inducing T lymphocyte responses. However, fibroblasts transfected with viral proteins directly induced antiviral cytotoxic T lymphocyte responses in vivo, without involvement of host APCs. Fibroblasts induced T cells only in the milieu of lymphoid organs. Thus, antigen localization affects self-nonself discrimination and cell-based vaccine strategies.     

Localization of corticotropin-releasing factor in primary and secondary lymphoid organs of the rat

Cells of the immune system produce a variety of neuropeptides or peptide hormones, either constitutively or upon induction, and possess specific neuropeptide receptors that display ligand-receptor interactions similar to those described in the central nervous system (CNS). These findings suggest that specific subsets of lymphoid cells can produce and respond to peptides previously thought to be principally neural mediators. Recently, corticotropin releasing factor (CRF) mRNA was detected in the rat thymus and spleen, although the cells that synthesize CRF were not identified. We examined the localization of CRF and its mRNA in the rat spleen, thymus, and mesenteric lymph nodes using immunocytochemistry (ICC) and in situ hybridization (ISH), respectively. Immunoreactive CRF was present in cells in the marginal zone and red pulp of the spleen, in connective tissue septa and the subcapsular region of the thymus, and in the medullary cords and sinuses of the mesenteric lymph nodes. Dual ICC/ISH for CRF and its mRNA, respectively, demonstrated CRF mRNA over CRF-immunoreactive cells, suggesting CRF synthesis. Double-label ICC for CRF and markers for specific immunocyte subsets suggest that CRF+ cells in the spleen and thymus are macrophages. CRF+ cells in primary and secondary lymphoid organs reside in compartments that are innervated by sympathetic nerves, and some cells appears to be contacted by noradrenergic sympathetic nerve fibers, suggesting that CRF release may be influenced by the sympathetic nervous system, as it is in the hypothalamo-pituitary-adrenal axis. The presence of CRF in organs of the immune system suggests that this neuropeptide may modulate immune functions after paracrine release.     

Targeted mutation in the Fas gene causes hyperplasia in peripheral lymphoid organs and liver

Fas, a type I membrane protein that transduces an apoptotic signal, is expressed in lymphocytes as well as in various tissues such as the liver, lung and heart. The mouse lymphoproliferation (lpr) mutation is a leaky mutation in Fas. By means of gene targeting, we generated a mouse strain which is completely deficient in Fas. In addition to the massive production of lymphocytes, the Fas-null mice showed substantial liver hyperplasia, which was accompanied by the enlargement of nuclei in hepatocytes. The Fas system seems to play a role in the apoptotic process to maintain homeostasis of the liver as well as the peripheral lymphoid organs.     

Immunohistochemical investigations of lymphocytes in the lymphoid organs of cyclophosphamide treated chickens

The localization of lymphocytes in the lymphoid organs of cyclophosphamide (Cy) treated chickens and untreated control chickens was compared immunohistochemically using a variety of monoclonal antibodies (CT3, 2-6, 11-39, TCR1, TCR2, TCR3, L22, 11G, 3E8, B-4D-4, A-13). In the Harderian glands of Cy treated chickens, an an increase of T cells was observed, though T cells were a few in untreated controls. These increased T cells consisted of CD4 positive or CD8 positive cells. Further, these T cells were stained with TCR2 or TCR3 antibody, and a small number of cells were stained with TCR1 antibody. In other lymphoid organs such as the bursa of Fabricius, thymus, spleen and cecal tonsils, B lymphocyctes severely decreased or disappeared in Cy treated chickens, though no significant alteration in T cell distribution was observed.     

Endoglin (CD 105) expression in human lymphoid organs and placenta

Endoglin (CD 105) is a cell surface antigen widely expressed on vascular endothelium, syncytiotrophoblast, some tissue macrophages, certain culture cells (including early leukemic B-lineage) and some endothelial cell lines. Though its relation to the transforming growth factor-beta (TGF-beta) receptor system is well documented, its function and detailed pattern of expression still remain to be clarified. We examined the differential tissue distribution of endoglin in human lymphoid organs and placenta with several anti-CD 105 monoclonal antibodies (mAbs) using an indirect immunoperoxidase technique, and performed semi-quantitative measurements using an image-analyzing system for comparison. Arterial, venous and capillary endothelia in these organs were reactive with anti-CD 105 mAbs at varying intensities. Interestingly, a distinctly stronger staining pattern was observed in the high endothelial venules (HEVs) which may indicate a special role for endoglin in lymphocyte trafficking. Syncytiotrophoblast expressed endoglin strongly on their apical cell membrane. Extravillous trophoblasts at certain locations selectively expressed endoglin on their cell membranes, suggesting a special role for this surface antigen during trophoblast differentiation.     

Morphologic rearrangement of lymphoid organs of birds and tailless amphibia during surgical intervention on internal organs

There are reports that suggest cryosurgical techniques may be a useful adjunct or even a viable alternative to surgical resection for hepatobiliary malignancies. Our objective was to evaluate the clinical results following cryoablation in conjunction with surgical resection for advanced hepatic tumors. Cryosurgical techniques were used in 25 consecutive patients with advanced liver tumors (1) to achieve a > 1-cm tumor-free margin when standard surgical margins were close, (2) to manage multiple tumor nodules with or without standard surgical resection, or (3) to increase chemotherapy response rates in conjunction with hepatic arterial portocath placement. In these 25 patients cryoablation was applied to 44 of 91 lesions--independently in four patients and in combination with hepatic resection in 21 patients. Cryoablation was used in seven patients because of close surgical margins. In 18 patients cryosurgery was used for complete lesion ablation. In 14 of the 18 patients cryosurgery and resection were used for different lesions; in four cryosurgery alone was used. Transient changes in hepatic enzymes, PT, PTT, and platelets were at maximum on postoperative days 1 to 3. Surgical mortality and morbidity rates were 4% and 68% respectively. Coagulation abnormalities were common; at least 30% reduction in platelets occurred in all patients and a > 50% reduction occurred in 15 of 25 (60%). Sixteen patients had a PT > 15 sec and five of these 16 also had platelet count < 50,000. Associated complications included one wound hematoma, one GI hemorrhage, one intracranial hemorrhage, and one hepatic hemorrhage from the cryosurgical site. 96%, 66%, 49%, 35%, and 20% of patients were surviving respectively at 6, 12, 18, 24, and 36 months. This report helps define the risks and results of cryosurgical ablation in conjunction with surgical resection for very advanced hepatobiliary tumors. Management of lesions contiguous to major blood vessels can include the Pringle maneuver or total hepatic vascular isolation. Cryoablation can be applied carefully as a complement to resection to achieve total tumor ablation in selected otherwise unresectable patients.     

A microscopic investigation of the lymphoid organs of the beluga, Delphinapterus leucas

Lymphoid organs from belugas, Delphinapterus leucas, ranging in age from less than one to 16 years, were harvested during a sanctioned hunt to investigate morphology. The spleen is divisible into red and white pulp and a stroma consisting of a reticular network, a collagenous capsule, and trabeculae containing smooth muscle bundles. White pulp areas appear to be devoid of follicles and consist mainly of periarteriolar lymphatic sheaths (PALS), that are larger in younger than in older belugas. Definitive marginal zones between red and white pulp are difficult to discern in older belugas. Lymph nodes are similar to those of other mammals; they possess a follicular cortex surrounding a vascular medulla composed of lymphatic cords and sinuses. Smooth muscle is abundant in the medullary region, usually in close proximity to sinuses. The expansive nodular mass at the root of the mesentery, often referred to as the "pseudopancreas," is similar to lymph nodes in microscopic architecture. Pharyngeal tonsils and gut-associated lymphoid tissue (GALT) are found along the digestive tract and display an "active" morphology. Tonsils are comprised of lobules of follicles separated by vascular connective tissue. Epithelial-lined crypts communicate with the pharyngeal lumen. GALT consists of diffuse and follicular lymphocytes within the intestinal mucosa and submucosa. The thymus is well developed in the younger belugas, with lobules divisible into densely packed cortical zones of thymocytes and more loosely arranged medullary lymphocytes. Hassall's corpuscles are occasionally visible within the medulla. Cetaceans diverged evolutionarily from other mammals over 55 million years ago. This study investigates changes in lymphoid organ morphology in a species that now inhabits a unique ecological niche. This study also lays the groundwork for functional investigation of the beluga immune system, particularly as it relates to differences between healthy and stranded animals.     

IL-2 receptor alpha-chain expression is independently regulated in primary and secondary lymphoid organs

The IL-2R is composed of three chains: IL-2R alpha, IL-2R beta, and IL-2R gamma. In mice, IL-2Ra is critical and determines IL-2 binding to the tripartite IL-2R complex. To extend our previous studies, which demonstrated that IL-2 regulates IL-2R alpha expression in vitro, we have analyzed expression in IL-2-deficient mice in vivo. As in control animals, CD4- CD8- thymocytes and bone marrow-derived B220+ pre-B cells were IL-2R alpha positive. In contrast, activated lymph node and splenic CD4 T cells (CD4+ CD69+) were found to be IL-2R alpha negative, whereas approximately 20% of the same cell populations from the MLR/lpr strain, which also accumulate large numbers of CD4-activated T cells in the presence of intact IL-2, retained expression. A similar pattern of IL-2R alpha expression was found among splenic CD8 cells from IL-2(-/-) and IL-2(+/-) animals. These findings demonstrate that in primary lymphoid organs, IL-2 is not directly involved in IL-2R alpha expression. However, at the level of mature lymphocytes, and more specifically CD4 T cells, IL-2 remains in vivo, as in vitro, the most critical cytokine controlling both IL-2R alpha expression and sensitivity to IL-2.     

全球化语境中的文明冲突与文明对话

在经济一体化,政治、文化多元化的世界潮流中,不同文化从冲突、碰撞走向融汇互补,是历史发展的必然,是新世纪人类文化的基本走向。以中华民族文化为代表的华夏文明,应弘扬自身的文化整合与重构强势,摒弃民族虚无主义的“全盘西化”和夜郎自天、自我封闭的“盆地意识”,广泛吸纳世界各民族的优秀文明成果,实践科学与人文的统一,技术与人性的统一,物质文明与精神文明的统一,在全球化背景和现代化进程中,创造更加辉煌灿烂的中华民族新文化。     

Sports and the immune system

Acute exercise is followed by a mobilization of white blood cells, mainly induced by increased levels of catecholamines and cortisol. NK-cells react the most intensive, they can increase fivefold after intensive exercise. Additionally a weak acute-phase reaction occurs. Most of these changes normalize during twenty-four hours. Parameters of the humoral immune system may be different from the pre-exercise levels up to seventy-two hours. Repeated physical exercise, which is typical for sports, is followed only by small changes of immunologic parameters under conditions of rest. Epidemiological studies give clues that the rate of upper respiratory tract infections in athletes can be described by a j-shaped curve. Moderately active subjects have the lowest rate of infection. For this influence of exercise on health mainly functional changes seem to be important. Especially after excentric exercise immunological cells can be seen in the muscle tissue, which remove destructed tissue. Not very much is known about the role of the immune system in the regeneration of tendons and other bradytrophic tissues.     

Ozone and the immune system

This review focuses on the effect on health of changes in the immune system secondary to ozone exposure and on various mechanistic hypotheses put forward. Beyond the problems related to the variability of study criteria (e.g. age, sex, concentration and duration of different types of exposure, the slightly volatile nature of ozone and the complexity of the immune system), ozone may induce immunostimulation as shown by intensified allergic phenomena or immunosuppression expressed by increased sensitivity to bacterial infections. Different functions of the immune response (for example macrophage and polynuclear phagocytic and bactericidal activity, NK activity, cytokine and antibody production ...) are affected. In terms of risk, the consequences of these changes depend on their intensity, their perennial nature and their association with particular genetic characteristics or other forms of external aggression, for example infection. The effect of exposure to a mixture of pollutants with unknown interactions should also be taken into consideration. Finally, the problem of normal but possibly exaggerated immune response to a compound whose allergenicity may have been modified by ozone must also be taken into account.     

Nutrition and the immune system

Synthesis of S- and N-arylpiperazinylalkyl derivatives of ethyl 2-thio-4-oxo-3,4-dihydro- and 2,4-dioxo-1,2,3,4-tetrahydropyrido [2,3-d] pyrimidine-5-carboxylate is described. Some of the obtained compounds are pharmacologically active.     

Differential effects of kynurenine and tryptophan treatment on quinolinate immunoreactivity in rat lymphoid and non-lymphoid organs

Quinolinate is a tryptophan metabolite and an intermediary in nicotinamide adenine dinucleotide (NAD+) synthesis in hepatocytes. Kynurenine is an upstream metabolite in the same biochemical pathway. Under normal physiological conditions, kynurenine is thought to be produced primarily in the liver as an NAD+ precursor. However, during immune stimulation or inflammation, numerous extrahepatic tissues convert systemic tryptophan to kynurenine, and its concentration subsequently rises dramatically in blood. The fate and role of extrahepatic kynurenine are uncertain. In order to begin addressing this question, the present study was performed to determine which cell types can produce quinolinate from either systemic tryptophan or kynurenine. By using highly specific antibodies to protein-coupled quinolinate, we found that intraperitoneal injections of tryptophan led to increased quinolinate immunoreactivity primarily in hepatocytes, with moderate increases in tissue macrophages and splenic follicles. In contrast, intraperitoneal injections of kynurenine did not result in any significant increase in hepatocyte quinolinate immunoreactivity, but rather led to dramatic increases in immunoreactivity in tissue macrophages, splenic white pulp, and thymic medulla. These findings suggest that hepatocytes do not make significant use of extracellular kynurenine for quinolinate or NAD+ synthesis, and that, instead, extrahepatic kynurenine is preferentially metabolized by immune cells throughout the body. The possible significance of the preferential metabolism of kynurenine by immune cells during an immune response is discussed.