A comparative study of gut‐associated lymphoid tissue in calf and chicken

The calf contains two types of Peyer's patches (PPs): jejunal and ileal. The ileal PP has been thought to be equivalent to the bursa of Fabricius (BF) as a central lymphoid organ. The morphologies of ileal and jejunal PPs in the calf were compared with those of the BF and the caecal tonsil (CT) in the chicken. Immunoglobulin G–positive (IgG⁺) cells appear in the follicles of them all and exhibited a dendritic appearance after birth. We investigated whether the IgG in these follicles was produced in situ. IgG‐producing cells were detected in the follicular medullas of the jejunal PP and the CT, but not in those of the ileal PP and the BF. CD4⁺ cells were distributed in the follicular medullas of the jejunal PP and the CT, but not in those of the ileal PP and the BF. The data suggest that Ig class switching occurs in both jejunal PP follicles and CT follicles, but does not occur in either the ileal PP follicles or the bursal follicles. Because CD4⁺ T cells would be prerequisite for Ig class switching in these follicles, IgG⁺ cells of the follicular medullas in the ileal PP and the BF would trap immune complexes from the gut lumen. The primary B‐cell repertoire might be selected by gut‐derived antigens in the ileal PP and the BF before seeding the periphery. Anat Rec 266:207–217, 2002. © 2002 Wiley‐Liss, Inc.     

A new hepatic encephalopathy model to monitor the change of neural amino acids and astrocytes with behaviour disorder

Background/Aims: To elucidate the pathogenesis of hepatic encephalopathy (HE), we developed a new HE model with behaviour disorder. Methods: Male Wistar rats were divided into four treatment groups: a HE model: acetaminophen (APAP)+3‐methylcholanthrene (3‐MC) group (APAP+MC group); control group: acetaminophen group; 3‐methylcholanthrene group; and a no‐treatment group. We monitored the changes of neural amino acids in the synaptic cleft and astrocytes in the brain during behaviour disorder. Results: In the APAP+MC group, alanine amino transferase, blood ammonia and glucose increased from 3 h and total bilirubin increased at 6 h. Prothrombin time was prolonged from 3 h in the APAP+MC group. The APAP+MC group exhibited centrilobular necrosis in the liver after 8 h. In the APAP+MC group, rats jumped vertically and this vertical activity increased significantly from 4 to 7 h. During the behaviour disorder, we found that glutamate and aspartate increased in the synaptic cleft from 4 h after treatment with APAP+3‐MC, glutamate increased 23.9‐fold at 7 h and aspartate increased 16.1‐fold at 4 h, whereas glutamine did not change. At that time, we observed morphological changes of the astrocytes by immunostaining for the glial fibrillary acidic protein. Conclusions: Our new HE model demonstrated that increased excitatory neural amino acids and morphological change in astrocytes were involved in the behaviour disorder that occurs with HE.     

Studies on colony specificity in the compound ascidian, Botryllus primigenus oka. II. In vivo bioassay for analyzing the mechanism of “nonfusion” reaction

Fusion experiments with three colonies (AC-BC-BD) by Tanaka and Watanabe indicated that the mixture of blood from two nonfusible colonies induced a “nonfusion” reaction (NFR)-like responses. Thus, artificial mixture of the blood from two nonfusible colonies is expected to result in NFR-like reactions. The present study deals with an in vivo bioassay using syngeneic and allogeneic blood injections. Syngeneic injection of whole blood induced no response, while allogeneic injection of whole blood induced inflammatory responses indicating recognition of allogeneic tissue. Syngeneic injection of blood plasma or blood cells induced no response. On the other hand, allogeneic injection of blood cells resulted in a response similar to that of whole blood injections. Allogeneic blood plasma induced only weak responses. It is hypothesized that NFR is initiated by the mutual interaction between blood cells and blood humoral factor(s).     

Effects of vitamin D3 analogues on parathyroid hormone secretion and calcium metabolism in vitamin D-deficient rats

22-Oxa-1α, 25-dihydroxyvitamin D₃ (OCT) and 2β-(3-Hydroxypropoxy)-1α, 25-dihydroxyvitamin D₃ (ED-71) are novel synthetic vitamin D₃ analogues. In order to examine their calcemic actions on intestine and bone, we have investigated the effects of OCT and ED-71 on intestinal Ca transport, bone mobilization and plasma parathyroid hormone (PTH) level in vitamin D-deficient rats. The vitamin D-deficient rats were intravenously given either 6.25μg/kg or 0.2μg/kg of 1,25-D₃, OCT or ED-71 and theirplasma Ca levels and intestinal Ca transport were measured periodically. At a high dose, 1,25(OH)₂D₃ and ED-71 showed a strong biphasic stimulation of intestinal Ca transport and bone mobilization, and reduced the plasma PTH levels to the normal level completely. On the other hand, OCT failed to suppress the PTH secretion although it exerted first phase action on the both intestinal Ca transport and bone mobilization in vitamin D-deficient rats. The reason why OCT failed to suppress the PTH secretion even at a high dose, has not yet been clarified, but it may be at least in part due to its weak calcemic action and short half-life in plasma.     

Studies on colony specificity in the compound ascidian,Botryllus primigenus oka. I. Initiation of “nonfusion” reaction with special reference to blood cells infiltration

When two incompatible colonies of the compound ascidian, $\text{Botryllus primigenus}$ Oka come into contact, a specific rejection, called “nonfusion” reaction (NFR), always occurs in the contact area between them. At the beginning of the NFR, concentrations of cells were always observed near the ampullae tips. In the present study, it was revealed that these cells appear to be blood cells infiltrating through the ampullae and were identified as morula cells (vanadocytes). When India ink was injected into vessels prior to the occurrence of NFR, it leaked from the tips of the ampullae into the test matrix, suggesting an increase in the permeability of the ampullar epidermis. Experimental studies to elucidate the mechanism of NFR were carried out. Contact between a colony piece and a zooid-free ampullae fragment or overlapping of one colony to another, respectively, resulted in NFR only at one side of a pair. Furthermore, in stage 3 of NFR, when an opaque area was pushed with a pair of forceps and the blood in this area was transferred to healthy part of vessels, the stoppage of blood flow and subsequent contraction of vessels always took place in the latter. These observations suggest that ampullae penetration into the opposite colony is essential to NFR and that NFR is directly initiated in the ampullar lumen.     

A comparative study of gut-associated lymphoid tissue in calf and chicken

The calf contains two types of Peyer's patches (PPs): jejunal and ileal. The ileal PP has been thought to be equivalent to the bursa of Fabricius (BF) as a central lymphoid organ. The morphologies of ileal and jejunal PPs in the calf were compared with those of the BF and the caecal tonsil (CT) in the chicken. Immunoglobulin G-positive (IgG(+)) cells appear in the follicles of them all and exhibited a dendritic appearance after birth. We investigated whether the IgG in these follicles was produced in situ. IgG-producing cells were detected in the follicular medullas of the jejunal PP and the CT, but not in those of the ileal PP and the BF. CD4(+) cells were distributed in the follicular medullas of the jejunal PP and the CT, but not in those of the ileal PP and the BF. The data suggest that Ig class switching occurs in both jejunal PP follicles and CT follicles, but does not occur in either the ileal PP follicles or the bursal follicles. Because CD4(+) T cells would be prerequisite for Ig class switching in these follicles, IgG(+) cells of the follicular medullas in the ileal PP and the BF would trap immune complexes from the gut lumen. The primary B-cell repertoire might be selected by gut-derived antigens in the ileal PP and the BF before seeding the periphery.     

Siphonaxanthin,a carotenoid from green algae,suppresses advanced glycation end product-induced inflammatory responses

Journal of Natural Medicines - Advanced glycation end products (AGEs) induce inflammation and contribute to the pathogenesis of atherosclerosis. Although many studies have demonstrated the...