Extent of regional lymphadenectomy and number-based nodal classification for non-ampullary duodenal adenocarcinoma

BACKGROUND

This study aimed to evaluate the adequate extent of regional lymphadenectomy according to tumor location and the impact of number-based nodal classification on survival in patients with non-ampullary duodenal adenocarcinoma (NADAC).

METHODS

A total of 85 patients with NADAC who underwent surgery were enrolled. The frequency of metastasis was calculated for each node group in the respective tumor locations for 63 patients who underwent lymphadenectomy for pT2-pT4 tumor.

RESULTS

The frequency of metastasis in the pancreaticoduodenal (nos. 13 and 17) and superior mesenteric artery (no. 14) nodes was high (16.7 %-52.3 %) regardless of tumor location. Metastasis in the perigastric (nos. 3 and 4d) and right celiac artery (no. 9) nodes was not uncommon (14.3 %-22.2 %) for tumors in the first portion. The frequency of metastasis in the pyloric (nos. 5 and 6) and the other peripancreaticoduodenal (nos. 8 and 12) nodes varied depending on tumor location but could not be ignored for staging. When these nodes were classified as regional nodes, the 5-year survival in patients with pN0, pN1 (1-2 positive nodes), and pN2 (≥3 positive nodes) were 82.9 %, 51.7 %, and 19.2 %, respectively (p < 0.001). pN classification independently predicted survival (pN1, p = 0.022; pN2, p < 0.001).

CONCLUSIONS

Nos. 5, 6, 8, 12, 13, 14, and 17 nodes in all advanced NADAC and nos. 3, 4d, and 9 nodes in advanced NADAC in the first portion should be considered as regional nodes for accurate staging. The number-based nodal classification allows good patients' prognostic stratification.

Mirizzi Syndrome Type IV Successfully Treated with Peroral Single-operator Cholangioscopy-guided Electrohydraulic Lithotripsy: A Case Report with Literature Review

A 76-year-old man presented with liver dysfunction and intrahepatic bile duct dilatation. Imaging studies showed two large stones that had become impacted in the common hepatic duct, which was fused with the gallbladder. The patient was diagnosed with Mirizzi syndrome type IV. Hepaticojejunostomy and stone removal failed due to dense gallbladder adhesions involving the right hepatic artery. The bile flow was temporarily restored; however, the patient experienced cholangitis 16 months later. The stones were extracted via peroral single-operator cholangioscopy (SOC)-guided electrohydraulic lithotripsy. This is the first case in which stones were completely removed by SOC-guided treatment in a patient with Mirizzi syndrome type IV.

Neuron-specific enolase level is a useful biomarker for distinguishing amyotrophic lateral sclerosis from cervical spondylotic myelopathy

The current study aimed to evaluate whether cerebrospinal fluid (CSF) neuron-specific enolase (NSE) levels are elevated in amyotrophic lateral sclerosis (ALS) and are effective in distinguishing ALS from cervical spondylotic myelopathy (CSM). We retrospectively evaluated 45 patients with ALS, 23 with CSM, 28 controls, and 10 with Parkinson's disease (PD) who underwent analysis of CSF NSE levels. The control group comprised patients aged above 45 years who underwent lumbar puncture because of suspected neurological disorders that were ruled out after extensive investigations. CSF NSE levels were evaluated using the electro-chemiluminescent immunoassay. The ALS group had significantly higher CSF NSE levels than the CSM and control groups (P < 0.001 for both comparisons). The CSM, control, and PD groups did not significantly differ in terms of CSF NSE levels. A receiver-operating characteristic curve analysis was performed to assess the diagnostic value of CSF NSE levels in distinguishing ALS from CSM. The area under the curve for CSF NSE levels was 0.86. The optimal cutoff value was 17.7 ng/mL, with a specificity of 87% and a sensitivity of 80%. Hence, CSF NSE levels are elevated in ALS and are effective in distinguishing ALS from CSM.

Subacute Combined Degeneration of the Spinal Cord Caused by Autoimmune Gastritis

A 68-year-old woman presented with a 2-year history of worsening unsteady gait. Her neurological examination revealed peripheral neuropathy with lower limb sensory dominance. T2-weighted imaging revealed a disorder of the posterior cervical cord. Blood test findings revealed vitamin B₁₂ deficiency, and gastroscopy revealed typical findings of autoimmune gastritis. She received vitamin B₁₂ supplementation, but some peripheral neuropathy symptoms persisted due to longstanding vitamin B₁₂ deficiency. Asymptomatic patients should undergo gastroscopy to detect autoimmune gastritis, as chronic vitamin B₁₂ deficiency causes irreversible peripheral neuropathy.

Posterior reversible encephalopathy syndrome with extensive cytotoxic edema after blood transfusion: a case report and literature review

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is described as a clinical-radiological disease entity with good prognosis. In brain MRI, PRES generally presents with vasogenic edema. Although PRES is induced by various causes, a small number of PRES cases have occurred after red cell blood transfusion. It is unclear whether there are characteristic features in PRES after blood transfusion.

CASE PRESENTATION

Here, we report a case of 75-year-old Japanese woman who had acute exacerbation of subacute anemia by bleeding from gastric ulcer. After receiving a red cell blood transfusion, she showed disturbance of consciousness with extensive cytotoxic and small vasogenic edema in the occipitoparietal area on brain MRI. She was diagnosed as PRES and suffered irreversible impairments of visual acuity and fields in both eyes. We summarized and discussed clinical features of cases with PRES after blood transfusion.

CONCLUSIONS

A total of 21 cases including the present one have been reported as PRES after blood transfusion. Of the cases, 20 of 21 were female, and 15 of 17 developed PRES in the course of chronic anemia lasting over 1 month. Anemia was severe in 15 of 20 cases, with hemoglobin levels < 3.5 g/dl. In 14 of 17 cases, hemoglobin levels increased to 5 g/dl by red cell blood transfusion until the onset of PRES. On brain MRI, 2 of 21 cases showed cytotoxic edema and 3 of 21 cases showed irreversible neurological disturbance. In this patient, the occurrence of PRES in subacute anemia and the presence of extensive cytotoxic brain edema with irreversible neurological deficits were characteristic points. When treating severe anemia, even with a subacute progression, we should consider a possibility that PRES occurs after blood transfusion with extensive cytotoxic brain edema and irreversible neurological changes.

[Lower cranial polyneuropathy in zoster sine herpete presenting with pain in the ear and throat: a case report]

A 64-year-old woman developed acute paralysis of glossopharyngeal, vagus, accessory, and hypoglossal nerves on the left side after pain in the head and the left ear and throat. Cerebrospinal fluid examination revealed lymphocytic pleocytosis and elevated protein concentration. Varicella-zoster virus (VZV)-DNA was detected by PCR from cerebrospinal fluid. The diagnosis of lower cranial polyneuropathy due to VZV reactivation was made. After oral administration of an anti-viral agent and steroid, all symptoms and signs dramatically improved. Notably, there was no evidence of cutaneous or mucosal rash during the whole course of the disease. VZV reactivation should be included in the differential diagnosis of acute lower cranial polyneuropathy, especially with pain in the ear and throat, even without cutaneous or mucosal rash.

Laparoscopic right hemicolectomy for a patient with idiopathic retroperitoneal fibrosis: A case report

A 62-year-old man with abdominal pain and lumbago was admitted to our hospital. Blood examination revealed renal insufficiency, and CT revealed retroperitoneal fibrosis causing bilateral hydrocele and ureteral compression. A colonoscopy was performed to rule out secondary retroperitoneal fibrosis due to malignancies, and this imaging revealed an ascending colon cancer. Laparoscopic right hemicolectomy with lymphadenectomy and retroperitoneal biopsy were performed. The retroperitoneum was filled with hard, white fibrous tissue, which made it difficult to mobilize the right mesocolon from the retroperitoneum. Devascularization performed before mobilization allowed for a safe and oncologically feasible procedure. Histologically, there were no malignant cells in the retroperitoneal tissue. The patient has been without colon cancer reoccurrence for 4 years. When the surgical challenges that distinguish these patients from ordinary cases are recognized preoperatively, laparoscopic colectomy may be a feasible option for patients with colorectal cancer with idiopathic retroperitoneal fibrosis.

Usefulness of Pseudocontinuous Arterial Spin-Labeling for the Assessment of Patients with Head and Neck Squamous Cell Carcinoma by Measuring Tumor Blood Flow in the Pretreatment and Early Treatment Period

BACKGROUND AND PURPOSE

For the assessment of the treatment response in non-surgical treatment, tumor blood flow provides the functional information of the tumor which is different from the morphological information such as tumor volume. The purpose of this study was to evaluate the diagnostic value of tumor blood flow values obtained by pseudocontinuous arterial spin-labeling in patients with head and neck squamous cell carcinoma.

MATERIALS AND METHODS

Forty-one patients with head and neck squamous cell carcinoma were evaluated by using pseudocontinuous arterial spin-labeling. Quantitative tumor blood flow was calculated at the pretreatment and the early treatment periods in all the patients, and the percentage change of tumor blood flow between the two was calculated. At the early treatment period, based on their tumor volume reduction rate, we divided the patients into stable disease and partial response groups for a subgroup analysis. The local control or failure was confirmed either by histopathology or by radiologic evaluation within the follow-up.

RESULTS

Pretreatment tumor blood flow in patients in the failure group was significantly lower than that in patients in the local control group. In the subgroup analysis of patients with stable disease, the percentage change of tumor blood flow was significantly larger (due to the tumor blood flow increase from pretreatment value) in the local control group than in the failure group. In addition, in patients with a partial response, the percentage change of tumor blood flow was significantly smaller (due to the tumor blood flow decrease from the pretreatment value) in the local control group than in the failure group. The accuracy for determination of the local control group or the failure group in pretreatment tumor blood flow was 0.83 and that in the combination use of the percentage change of tumor blood flow and tumor volume in the early treatment period was 0.93.

CONCLUSIONS

Tumor blood flow obtained by pseudocontinuous arterial spin-labeling can be useful for the determination of local control. The combined use of the percentage change of tumor blood flow and tumor volume had particularly high diagnostic accuracy.

Differentiation of squamous cell carcinoma and inverted papilloma using non-invasive MR perfusion imaging

OBJECTIVES

To investigate the diagnostic value of tumour blood flow (TBF) obtained with pseudocontinuous arterial spin labelling for the differentiation of squamous cell carcinoma (SCC) and inverted papilloma (IP) in the nasal or sinonasal cavity.

METHODS

We retrospectively analysed the cases of 33 patients with SCC and 8 patients with IP in the nasal or sinonasal cavity. Pseudocontinuous arterial spin labelling scanning was performed for all patients using a 3.0-T MR unit. Quantitative TBF values were measured by two neuroradiologists by respectively delineating the whole-tumour regions of interest, and the mean of them was determined as TBF value in each patient. Additionally, the presence of imaging findings of convoluted cerebriform pattern (CCP) on MR T2 weighted images was determined in all patients. As a subgroup analysis, patients with IP were divided into aggressive and non-aggressive IPs depending on their progression range. First, an intraclass correlation coefficient (ICC) of TBF values between two neuroradiologists was determined. Next, a statistical comparison of the TBF value by a Mann-Whitney U test between the patients with SCC and IP was performed. Additionally, the comparison by an ANOVA with a post hoc test of Tukey's method among the SCC, non-aggressive IP and aggressive IP groups was also performed. If significance was observed, the diagnostic accuracy to differentiate SCCs from IPs was calculated. Diagnostic accuracy by CCP findings alone and by the combination of CCP findings and TBF were also assessed.

RESULTS

The ICC of TBF values between two neuroradiologists was 0.82. The mean TBF values in the patients with SCC, all patients with IP, those with aggressive IP and those with non-aggressive IP were 141.2 ± 33.1, 77.8 ± 31.5, 109.4 ± 16.7 and 58.8 ± 19.9 ml 100 g⁻¹ min⁻¹, respectively. A significant difference was observed between SCC and IP (p < 0.001), SCC and non-aggressive IP (p < 0.01) and non-aggressive IP and aggressive IP (p < 0.01). The diagnostic accuracy values obtained with receiver operating characteristic curve analysis for the differentiation of SCC from IP and for SCC from non-aggressive IP were 0.90 and 0.92, respectively. The diagnostic accuracy was elevated (0.95 from 0.88) by adding the TBF value to CCP findings.

CONCLUSIONS

The pseudocontinuous arterial spin labelling technique can be a useful non-invasive diagnostic tool to differentiate SCC from IP in nasal or sinonasal cavity.

Diagnosis of ischemic small bowel disease by measurement of serum intestinal fatty acid-binding protein in patients with acute abdomen: a multicenter, observer-blinded validation study

BACKGROUND

Intestinal fatty acid-binding protein (I-FABP) is a low-molecular-mass (15 kDa) cytosolic protein found exclusively in the epithelial cells of the small bowel mucosa. We aimed to evaluate the clinical usefulness of serum I-FABP measurement for the diagnosis of ischemic small bowel disease.

METHODS

Patients with a clinical diagnosis of acute abdomen were recruited for this multicenter trial at one university hospital and nine city hospitals over a 13-month period. Serum I-FABP levels were measured in 361 eligible patients by an enzyme-linked immunosorbent assay using a specific monoclonal antibody.

RESULTS

Of the 361 patients, 242 underwent surgery, and small bowel ischemia was diagnosed in 52 patients. The mean serum I-FABP level in the patients with small bowel ischemia was 40.7 ± 117.9 ng/ml, which was significantly higher than that in patients with non-ischemic small bowel disease (5.8 ± 15.6 ng/ml) and those with non-small bowel disease (1.8 ± 1.7 ng/ml). The serum I-FABP cutoff level for the diagnosis of small bowel ischemia was 3.1 ng/ml. Serum I-FABP was more efficient than conventional biochemical markers, in terms of sensitivity and positive and negative predictive values, in the diagnosis of small bowel ischemia. However, its specificity was slightly lower than that of creatinine phosphokinase or lactate dehydrogenase. The positive and negative likelihood ratios of serum I-FABP were 3.01 and 0.29, respectively.

CONCLUSION

Serum I-FABP measurement is a non-invasive method that is potentially useful for the efficient identification of patients with acute abdomen who are at risk of small bowel ischemia.

[Clinical experience of sivelestat sodium hydrate for severe reexpansion pulmonary edema; report of a case]

An 81-year-old man was referred to our hospital for the treatment for left spontaneous pneumothorax. A chest X-ray revealed a left-sided total pneumothorax and complete collapse of the lung. After intravenous administration of methylprednisolone, a 16 Fr chest tube was inserted, and drainage was started without negative pressure suction. Four hours after chest tube insertion, the patient's condition deteriorated. He complained severe cough and dyspnea, and pulse oximetry reading was 70%. A repeat chest X-ray demonstrated diffuse reexpansion pulmonary edema (RPE) on the left. After mechanical ventilation and intravenous infusion therapy with sivelestat sodium hydrate, methylprednisolone and ulinastatin were started, P(O2)/ Fi(O2) ratio improved rapidly. He was extubated on hospital day 6 and was discharged after pleurodesis for the pneumothorax. This case suggests that sivelestat sodium hydrate may be useful for the treatment for RPE.

[A case of advanced gastric cancer with multiple liver metastases successfully treated with TS-1 and CDDP]

A Case of Advanced Gastric Cancer with Multiple Liver Metastases Successfully Treated with TS-1 and CDDP: Akihiro Tsukahara, Kazuhiro Kaneko and Syuji Tanaka (Dept. of Surgery, Niigata Prefectural Koide Hospital) Summary A 70-year-old advanced gastric cancer patient with liver and lymph node metastases was treated by chemotherapy with TS-1 and CDDP. One course consisted of administration of TS-1 100 mg/body for 21 days followed by 14 days rest and infusion of CDDP 80 mg/body on day 8. At the end of 2 courses, the primary tumor showed a hypertrophic wall, but a partial response of the liver metastases (reduction ratio was 78.3%) and a complete response of the LN metastasis were achieved. PR and CR were maintained after 4 courses. There were no remarkable side effects for 4 courses. This chemotherapy may have therapeutic efficacy in cases of advanced gastric cancer with liver and lymph node metastases.

Thrombopoietin levels and peripheral platelet counts following living related donor liver transplantation

BACKGROUND/AIMS

Thrombopoietin is the primary hematopoietic growth factor. Thrombopoietin deficiency may cause thrombocytopenia in advanced liver disease. The aim of our study was to investigate the relevance of thrombopoietin levels to peripheral platelet counts in patients with liver disease who underwent LRDLT (living related donor liver transplantation).

METHODOLOGY

We divided the six patients who underwent LRDLT into two groups. Group 1 had thrombocytopenia and group 2 had normal platelet counts. We measured serum thrombopoietin and peripheral platelet counts before and after LRDLT.

RESULTS

Pre-LRDLT thrombopoietin and peripheral platelet counts were lower in group 1 than in group 2. Thrombopoietin in group 1 significantly increased on the first day after LRDLT and peripheral platelet counts in group 1 increased following the rise in thrombopoietin (p < 0.05). Moreover, a marked increase in thrombopoietin and peripheral platelet counts was found in splenectomized patients during LRDLT.

CONCLUSIONS

These findings suggested inadequate thrombopoietin production in advanced stage liver disease which caused thrombocytopenia. Improvement of thrombopoietin production in graft liver function may contribute to increase of peripheral platelet counts.

[A case of advanced gastric cancer treated with paclitaxel and TS-1]

We treated a case of advanced gastric cancer with paclitaxel and TS-1. A 64-year-old man underwent total gastrectomy, splenectomy, and D2 + No. 16 a 2, b 1 lymph node (LN) dissection for gastric cancer. Computed tomography (CT) revealed metastases of supraclavicular and para-aortic LNs in the 4th postoperative month. Paclitaxel 90 mg was infused once a week, and TS-1 100 mg was administered daily. One course consisted of infusion of paclitaxel for 3 weeks followed by 2 weeks rest and administration of TS-1 for 4 weeks followed by 2 weeks rest. At the end of 4 courses of paclitaxel and 3 courses of TS-1, a partial response of the supraclavicular LN metastasis and a complete response of the para-aortic LN metastasis were achieved. There were no remarkable side effects for 2 years after the operation. This chemotherapy might be suitable to treat patients with LN metastases of advanced gastric cancer.

Splenectomy for reduction of excessive portal hypertension after adult living-related donor liver transplantation

BACKGROUND/AIMS

We investigated the effects of splenectomy on the reduction of excessive portal hypertension immediately after adult living-related donor liver transplantation, paying particular attention to peritransplanted portal pressure in seven adult patients.

METHODOLOGY

We studied the relationship between portal hypertension and hyperbilirubinemia in small-for-size graft liver transplantation.

RESULTS

In the three cases, the portal pressures increased beyond 30 cmH2O after living-related donor liver transplantation, despite the right lobe graft, and these patients underwent splenectomy. After splenectomy, their portal pressures decreased below 25 cmH2O. The portal pressure underwent auxiliary orthotopic partial liver transplantation due to the hypercitrullinemia and did not change after surgery (9.5 to 11.5 cmH2O). Interestingly, the hyperbilirubinemia occurring after living-related donor liver transplantation were as the primary result of direct bilirubin except for the patient with citrullinemia. The posttransplanted portal pressures were controlled below 25 cmH2O in all patients, with their peak serum total bilirubin levels not exceeding 15 mg/dL, and the patients were discharged without major complications. Three patients underwent splenectomy, and did not suffer from serious infection. The reduction in excessive portal hypertension after living-related donor liver transplantation might prevent liver injury and post-transplant hyperbilirubinemia.

CONCLUSIONS

However, splenectomy remains a life-threatening factor. Therefore, transplant surgeons encountering living-related donor liver transplantation must continue to seek out additional solutions to problems with excessive portal hypertension.

[Dormant chemotherapy by low-dose FP and low-dose UFT-E in recurrent gastric cancer with long-term survival--a case report]

We experienced a case of recurrent gastric cancer with a long-term survival. A 64-year-old man was admitted to the hospital for advanced gastric cancer in the upper stomach. Abdominal CT scan revealed para-aortic lymph nodal metastases. The patient underwent total gastrectomy, distal pancreatectomy, splenectomy, left adrenectomy, and left nephrectomy with D4 lymph node dissection, in what was a curability B resection. Conclusive findings were t2 (ss), n4, H0, P0, M0, and stage IVb. One year after the operation, para-aortic lymph node recurrence was evaluated. The patient was treated with low-dose cisplatin-5-FU therapy, and a partial response was observed and continued for over 2 years with an administration of UFT-E (300 mg/day). He died of repeated aggravation of para-aortic lymph node metastases 6 years and 2 months after the operation. We considered that the long-term survival of this patient was attributable to a 3-year tumor dormancy induced by low-dose cisplatin-5-FU therapy and administration of low-dose UFT.

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 Valpha14Jalpha281 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.

Participation of NK1.1+ T cells in the rejection of lpr alphabetaT cells when bone marrow cells of lpr mice are transplanted into B6 mice

When C57BL/6 (B6) mice were irradiated (9 Gy) and received bone marrow (BM) cells of B6-lpr/lpr mouse origin (i.e., lpr-->B6), all mice died within 6 days. In the irradiated B6 mice, radioresistant CD3 IL-2Rbeta+ NK cells and IL-2Rbeta+ CD3int cells (i.e., CD3int cells of extrathymic origin) remained, especially in the liver. There were two subsets, NK1.1+ and NK1.1-, among the IL-2Rbeta+ CD3int cells. However, the NK1.1+ subset (i.e., NK1.1- T cells) was much more radioresistant, and the majority of CD3int cells belonged to this subset in irradiated mice. The expansion of lymphocytes from injected BM cells did not occur in the irradiated B6 mice. However, such expansion did take place in irradiated B6-lpr/lpr mice injected with both BM cells of B6-lpr/lpr and B6 origin. As a result, the mice subjected to BM cells survived. Irradiated B6 mice were treated in vivo with anti-NK1.1 mAb or anti-asialoGM1 antibody to eliminate NK cells alone or both NK cells and NK1.1+ T cells. When irradiated B6 mice were pretreated with anti-NK1.1 mAb, the mice could survive. These results suggest that intact NK1.1+ T cells of extrathymic origin may recognize abnormal BM cells with the lpr gene and inhibit the expansion of lymphocytes, including abnormal double-negative CD4 8 cells, in B6-lpr/lpr mice. To inhibit the expansion of lymphocytes, mechanisms other than Fas ligand/Fas molecules on extrathymic T cells may be responsible.

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- alpha beta T cells expressing a low density of interleukin-2 receptor beta-chain (IL-2R beta). 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-2R beta. 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-2R beta. 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.

Circadian rhythm of leucocytes and lymphocytes 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, gammadelta T cells, and CD8+ subset--showed an increase in the daytime (i.e. daytime rhythm). The other group--T cells, B cells, alphabeta 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.

Mouse liver T cells: their change with aging and in comparison with peripheral T cells

Mouse liver contains both IL-2Rbeta- (or low positive) high T-cell receptor (TCR(hi)) cells and IL-2Rbeta+ intermediate TCR (TCR(int)) cells. TCR(int) cells consist of natural killer 1.1 (NK1)+ and NK1- subsets. NK1- TCR(int) cells increase constantly with age whereas TCR(hi) cells decrease. NK1+ TCR(int) cell proportions in the liver increase until middle age and decrease thereafter. Although NK1+ TCR(int) cells in other organs are few regardless of age, NK1- TCR(int) cells gradually appear in other lymphoid organs with aging. Skewed usage of Vbeta7 and Vbeta8 TCR was observed in NK1+ TCR(int) cells in the liver but the predominance was less obvious in NK1- TCR(int) and TCR(hi) cells in the liver and other organs. TCR V alpha14 messenger RNA (mRNA) was detected in NK1+ TCR(int) cells but not in the other two populations. In contrast, although NK1+ TCR(int) cells contain virtually no V alpha11+ T cells, NK1- TCR(int) cells contain a much higher proportion (approximately 12%) of V alpha11+ T cells, whereas approximately 4% of TCR(hi) cells are V alpha11+. NK activities of liver mononuclear cells (MNC) and splenocytes decrease with aging, although the former is always greater than the latter. NK activity of liver MNC is a function of NK cells, partly NK1+ TCR(int) cells but not NK1- TCR(int) cells or TCR(hi) cells. These results suggest that lymphocytes of liver and other organs at old age are no longer occupied solely by conventional thymus-derived T cells, and the increase of extrathymic IL-2Rbeta+ NK1- TCR(int) cells in liver and periphery could be closely related to immunological changes with aging.

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-V beta 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 beta 2-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 V beta 3+ and V beta 11+ 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.

Absolute dependence of T cell receptor(hi) cell generation and relative dependence of T cell receptor(int) cell generation on the thymus

Recent evidence indicates that conventional T cells are generated by the mainstream of T cell differentiation in the thymus and acquire a high density of T cell receptor expression (i.e. TCRhi). In contrast, primordial T cells (or NK1.1+ T cells) are generated by the extrathymic pathways or an alternative intrathymic pathway and express an intermediate density of TCR (i.e. TCRint). To obtain further evidence, it was examined how thymus grafting influenced the distribution of T cell populations in athymic nude mice. When BALB/c nu/nu mice were engrafted with thymocyte-depleted BALB/c+/+ fetal thymi, two changes emerged after grafting: nude mice generated TCRhi cells de novo in the periphery as well as in the grafted thymi, and the absolute number of interleukin-2 receptor beta chain+ TCRint cells increased prominently in number in the periphery. Among thymic hormones tested, the administration of thymosin alpha induced a slight expansion of CD3int cells in nude mice. To examine a possible interaction of TCRint cells with TCRhi cells in the periphery, B6 nu/nu mice (Ly5.2+) were injected with TCRhi cells purified from the spleen of B6 Ly5.1 congenic mice. In this case, TCRint (Ly5.2+) cells expanded well in all tested organs of nude mice. These results suggest that the generation of TCRhi cells is absolutely dependent on the thymus and that TCRint cells expand under the influence of the thymus (humoral) and due to interaction with thymus-derived conventional T cells.