Tetsuya Tada

Circadian rhythm of leucocytes and lymphocyte subsets and its possible correlation with the function of the autonomic nervous system

There are physiological variations in the levels of leucocytes. Among these, the circadian rhythm is very important in terms of the magnitude. Since newly identified lymphocyte subsets (i.e. extrathymic T cells) have recently been detected, a comprehensive study of the circadian rhythm was conducted. All leucocytes were found to vary in number or proportion with a circadian rhythm and were classified into two groups. One group—granulocytes, macrophages, natural killer (NK) cells, extrathymic T cells, γδ T cells, and CD8+ subset—showed an increase in the daytime (i.e. daytime rhythm). The other group—T cells, B cells, αβ T cells, and CD4+ subset—showed an increase at night. Humans are active and show sympathetic nerve dominance in the daytime. Interestingly, granulocytes and lymphocyte subsets with the daytime rhythm were found to carry a high density of adrenergic receptors. On the other hand, lymphocyte subsets with the night rhythm carried a high proportion of cholinergic receptors. Reflecting this situation, exercise prominently increased the number of cells with the daytime rhythm. These results suggest that the levels of leucocytes may be under the regulation of the autonomic nervous system.

Autologous killing by a population of intermediate T-cell receptor cells and its NK1.1+ and NK1.1− subsets, using Fas ligand/Fas molecules

Self‐reactive clones, estimated by anti‐Vβ monoclonal antibodies (mAb) in conjunction with the Mls system, are confined to a population of intermediate (int) T‐cell receptor (TCR) (or CD3) cells (i.e. TCRint cells), but are not found among TCRhigh cells. The next questions to be answered are whether autologous killing is confined to TCRint cells and how such killing is mediated. In this study, 51Cr‐labelled thymocytes of syngeneic or allogeneic origin were used as target cells (4‐hr assay). When liver and splenic mononuclear cells (MNC) obtained from B6 mice were used as effector cells, prominent autologous killing was seen in liver MNC, but not splenic MNC. Such killing was not seen when thymocytes from B6‐lpr/lpr mice (i.e. Fas−) were used as target cells, nor when liver MNC from MRL‐gld/gld mice (i.e. Fas ligand−) were used as effector cells (target thymocytes of MRL‐+/+ mice). Cell separation experiments using a cell sorter revealed that autologous killing was mediated for the most part by CD3int cells, while allogeneic killing was mediated entirely by natural killer (NK) cells, TCRint cells and TCRhigh cells. Among CD3int cells, the NK1.1+ subset (i.e. NK1.1+ T cells) manifested a higher level of autologous killing than did the NK1.1− subset. Consistent with the results of a functional assay, it was found by reverse‐transcription–polymerase chain reaction (RT‐PCR) assay that CD3int cells among liver MNC showed the expression of Fas ligand mRNA, while thymocytes expressed Fas mRNA. When class I major histocompatibility complex (MHC)− thymocytes (from β2‐microglobulin‐deficient mice) were used as target cells, NK cells, but not CD3int cells, showed potent cytotoxicity. These results suggest that autologous killing is a major function of TCRint cells with self‐reactivity, and that such killing is mediated by means of Fas ligand/Fas molecules.

Self-reactive forbidden clones are confined to pathways of intermediate T-cell receptor cell differentiation even under immunosuppressive conditions

It is believed that self‐reactive forbidden T‐cell clones are generated by ‘failure’ of the pathway of T‐cell differentiation in the thymus, if it is disturbed. We examined how such forbidden clones are generated under immunosuppressive conditions. Mice were treated with an injection of deoxyspergualin, FK506, or cycloporin A. From day 3, the number of cells yielded by various organs decreased. Because of the resistance of intermediate (int) T‐cell receptor (TCR) cells (i.e. TCRint cells), they became more prominent in proportion than TCRhigh cells. TCRhigh cells are conventional T cells generated through the mainstream in the thymus, whereas TCRint cells are primordial T cells generated by the extrathymic pathway or an alternative intrathymic pathway. Similar to untreated mice, forbidden Vβ3+ and Vβ11+ clones in C3H/He (Mls‐1b2a) mice were confined to TCRint cells after treatment; there was no leakage of forbidden clones into TCRhigh cells in the thymus and periphery. In parallel with the increase in the proportion of TCRint cells, the proportion of forbidden clones also increased under immunosuppressive states, especially in the liver. Liver mononuclear cells isolated from treated mice still had the potential to mediate autologous killing. The present results suggest that the generation of self‐reactive clones is highly restricted to the pathways of TCRint cell differentiation even under immunosuppressive conditions.

ISCHEMIC COLITIS ARISING IN WATERSHED AREAS OF THE COLONIC BLOOD SUPPLY : A REPORT OF TWO CASES

There are several weak points in the colonic blood supply, known as watershed areas, which result from incomplete anastomoses of the marginal arteries. These watershed areas are more vulnerable to ischemic injury than other parts of the colon. We report herein the cases of two patients who developed ischemic colitis well localized in the cecum, and in the rectosigmoid region at Sudecks point, respectively. This report and our review of the literature suggest that watershed areas, including the splenic flexure, or Griffiths point, Sudecks point, and the ileocecal region, are high-risk regions for the development of ischemic colitis.

Late-Type Recurrence at the Port Site of Unexpected Gallbladder Carcinoma After a Laparoscopic Cholecystectomy : Report of a Case

Abstract A 73-year-old woman had a laparoscopic cholecystectomy for unexpected gallbladder cancer and 9 days later underwent both a liver bed resection and lymph node dissection. Four years later, she underwent a further resection of a port site recurrence of gallbladder cancer and no other site of recurrence was observed. The seeding of cancer cells during the removal of the resected gallbladder might have caused this tumor. This case may show that the port site recurrence did not necessarily indicate an incurable stage of the disease. In addition, an excision of the recurrent tumor also appeared to eliminate the disease in the patient.

Quick recovery in the generation of self-reactive CD4low natural killer (NK) T cells by an alternative intrathymic pathway when restored from acute thymic atrophy.

The thymus comprises the mainstream of T cell differentiation which produces conventional T cells and an alternative pathway which produces primordial T cells with intermediate density of T cell receptor (TCR)–CD3 complex on the surface (i.e. intermediate TCR cells or TCRint cells). We induced acute thymic atrophy in mice by an administration of hydrocortisone (10 mg) or irradiation (6.5 Gy). It was demonstrated that CD3intCD4lowNK1.1+ T cells were immediately generated by an alternative intrathymic pathway without passing through the double‐positive CD4+8+ stage, when restored from thymic atrophy (days 3–14). These CD3intCD4lowNK1.1+ T cells mediated self‐reactivity and appeared even in the periphery. mRNA of an invariant chain of TCR Vα14Jα281 gene product was detected in these CD4low T cells, but not remaining CD4high T cells. The mainstream of T cell differentiation in the thymus was not restored up to day 14 and there was no leakage of self‐reactive clones into the population generated through the mainstream. These results reveal that an alternative intrathymic pathway is associated with the generation of self‐reactive T cells, in an early restoration phase after thymic atrophy.

Conservative treatment of esophageal perforation related to a peptic ulcer with pyloric stenosis

We report a case of esophageal perforation (Boerhaave syndrome) caused by vomiting related to a duodenal ulcer with pyloric stenosis. A 45-year-old male presented with left chest pain and dyspnea after forceful vomiting. Chest radiography and computed tomography (CT) revealed a massive left pleural effusion and left tension pneumothorax. Abdominal CT revealed pyloric stenosis with a remarkably dilated stomach. Tube thoracostomy and nasogastric suction were immediately performed and we selected conservative treatment based on the following factors—a stable general condition without sepsis, early diagnosis, and good drainage. Esophagogastroduodenoscopy on hospital day 9 demonstrated a healing ulcer in the lower esophagus and pyloric stenosis. We performed distal gastrectomy as elective surgery for pyloric stenosis due to a duodenal ulcer on hospital day 30. In summary, an esophageal perforation with contamination spreading to the thoracic cavity was successfully treated with conservative treatment.

An allogeneic microenvironment influences the phenotype of intermediate T-cell receptor cells expanding in MRL-lpr/lpr mice.

MRL‐lpr/lpr (lpr) mice fall victim to autoimmune disease owing to a lymphoproliferative disorder mainly of double‐negative (DN) CD4− CD8−αβT cells expressing a low density of interleukin‐2 receptor β‐chain (IL‐2Rβ). It was previously revealed that the lpr gene is a defective Fas gene, into which an early transposon (ETn) of retrovirus is transfected. As a result of the failure of apoptosis, intermediate T‐cell receptor (TCR) cells (i.e. TCRint cells) with DN phenotype abnormally accumulate in the periphery of lpr mice. We investigated herein how these TCRint cells are selected in terms of CD4, CD8 and TCR in lpr mice. When a whole fraction of mononuclear cells (MNC) in various immune organs of lpr mice was injected into scid mice (allogeneic circumstance), CD8+ TCRint cells mainly expanded. They had a high density of IL‐2Rβ. This was true when bone marrow cells of lpr mice were injected into scid mice. On the other hand, when MNC of the spleen and bone marrow in lpr mice were injected into irradiated (9 Gy) lpr mice (syngeneic circumstance), the major expanding cells were DN TCRint cells expressing a low density of IL‐2Rβ. A cell‐sorting experiment for purified fractions demonstrated that only CD8+ cells reconstituted TCRint cells in scid mice. Namely, DN CD4− CD8− cells as well as CD4+ cells which once acquired the mature phenotype, no longer switched their phenotype. These results suggest that the phenotype of TCRint cells is influenced by the surrounding microenvironment.

Pyloroantrectomy and pedunculated short gastric-tube interposition in esophageal carcinoma patients associated with early gastric adenocarcinoma

Abstract Objective: Gastric carcinoma is one of the most common secondary malignancies in esophageal cancer patients. We herein report our surgical procedure for esophageal reconstruction in esophageal cancer patients associated with synchronous or metachronous early gastric adenocarcinoma. Methods: Gastric adenocarcinoma was removed by pyloroantrectomy with preservation of the right gastroepiploic artery and vein, and a pedunculated short gastric tube was used as an esophageal substitute in a Roux-en-Y fashion. Surgical data of six esophageal cancer patients who underwent this type of surgery between 1993 and 2012 were analyzed. Three patients had synchronous early gastric carcinoma and the remaining three patients had metachronous one. Results: The gastric tube was easily pulled up to the neck and any problem did not occur during this procedure. Postoperative complications, including leakage of esophagogastrostomy, acute respiratory failure, and diffuse peritonitis, were observed in three patients. No p...