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We found a substance in culture medium of neonatal pig liver fragments, which suppresses an immune response monitored by (3)H-thymidine incorporation using phytohemagglutinin (PHA)-stimulated lymphocytes. We named it as an immunosuppressive factor (ISF). To purify ISF, ammonium sulfate fractionation, DE52, SP-Sephadex, hydroxyapatite, blue Sepharose, heparin Sepharose and Superdex gel filtration columns were used. Using these purification procedures, ISF was purified 1,254-fold, with 9.2% recovery, from the culture medium of neonatal pig liver fragments, and was identified as arginase by its biochemical characteristics including molecular size, amino acid sequences of digested peptides and expression of arginase activity. The addition of ISF caused to decrease in arginine concentration in culture medium and at the same time DNA synthesis was suppressed dose-dependently, both of which were recovered by the addition of NOHA (N(G)-hydroxy-L-arginine), an arginase inhibitor. In addition, the depletion of arginine in culture medium also led to the inhibition of DNA synthesis. These results led us to the conclusion that immunosuppressive effect of ISF was due to arginase activity that decreased arginine concentration in culture medium, not to another function of ISF.

Microsatellite instability or replication error seems to be related to defective DNA mismatch repair genes, such as hMSH2, hMLH1, hPMS1 and hPMS2, which have been identified as causative genes of hereditary nonpolyposis colorectal cancers (HNPCC). Recently, it was reported that mutations at the simple repeated sequences in the transforming growth factor-beta type II receptor (TGF-beta RII) gene occurred in replication error-positive colorectal cancers. To determine genetic alterations in familial gastric cancers (FGC, we examined replication error using eight microsatellite DNA markers, and screened mutations in the hMSH2, hMLH1 and TGF-beta RII genes in six cases from four FGC kindreds. Moreover, hMTH1, a human homolog of the bacterial mutT gene, was also screened. Four of six (67%) cancers showed the replication error-positive phenotype, indicating that microsatellite instability is highly associated with not only HNPCC, but also FGC. No germline mutation was found in the whole coding sequences of hMSH2 and hMTH1, or in the conservative regions of hMLH1 in any patient, while one cancer DNA showed a somatic mutation at codon 682 (threonine to alanine) in hMSH2. No alteration was found at the small repeated sequences in TGF-beta RII in FGC tumor DNA. These results indicate that the carcinogenetic process of FGC may be different from that of HNPCC.

A 14-year-old female patient, admitted for a closer examination of liver tumour (hepatocellular adenoma), was diagnosed as having a congenital absence of the portal vein. The blood ammonia level (approximately 120 micrograms dl-1) in the superior mesenteric vein was markedly low compared to the normal value of 300-350 micrograms dl-1 in the portal vein. The decreased ammonia concentration and urease activity of the patient's faeces were demonstrated. The dominant intestinal flora in the faeces of the patient, before operation, was Bifidobacterium sp., Bifidobacterium breve, Bifidobacterium lonqum, Lactobacillus plantarum, and after the operation Bacteroides vulgatus, Veillonella parvula, Peptococcus magnus Bifidobacterium longum. In contrast, Bifidobacterium bifidum, Bacteroides ureolyticus, Bacteroides ovatus and Bacteroides distasonis, B. ovatus, Bifidobacterium adolescentis were dominant flora in the faeces of two healthy volunteers, respectively. Among microorganisms isolated from the patient, Morganella morganii, Candida sp., Eubacterium aerofacience and Eubacterium rectale were strongly positive in urease activity in vitro; Streptococcus mitior, Staphylococcus intermedius, Micrococcus kristinae, Selenomonas ruminantum, Bacteroides ureolyticus and Lactobacillus casei ss. pseudoplantarum from the healthy volunteers. These results imply the homeostatic regulation system of faecal ammonia concentration by urease-producing microorganisms in the patient.

Permanent tracheostomy and tracheoesophageal anastomosis were performed as a means of surgical intervention for the treatment of intractable aspiration pneumonia. Conventional methods of tracheoesophageal anastomosis have entailed various problems. The improved method devised by us uses the special histological features and enables safe and reliable anastomosis. By this method, the tracheal perichondrium is retained and the strength of the anastomosed portion of the trachea is maintained, the failure of sutures due to tension on the anastomotic site being prevented. Also, reanastomosis can be performed after the cure of primary disease.

A 14-year-old girl presented at the hospital after discovering an abdominal tumor. CT scan and ultrasonography indicated a hepatic tumor and also revealed the absence of the portal vein. The patient was admitted to excise the hepatic tumor. It was found that the venous blood from the small intestines flowed into the left renal vein and then emptied directly into the inferior vena cava. A tumor extending from the right lobe through the middle portion of the liver was excised. The postoperative course was satisfactory and marked regeneration of the residual hepatic tissue was observed. Also the blood level of ammonia in the superior mesenteric vein was low, approximately 120 micrograms/dl, compared to the normal value of 350 micrograms/dl in the portal vein. This low blood level may indicate the presence of some homeostatic control mechanism.

Serial sequential sections from a single tumor were examined by immunohistological staining with several monoclonal antibodies directed, respectively, to different tumor-associated carbohydrate epitopes. Staining patterns were compared with those of conventional staining with hematoxylin-eosin or periodate/Schiff's reagent. Each tumor showed different areas of staining with different antibodies, and the combined staining map shows a clear mosaicism of antigen expression within the same tumor. For example, some areas of a given tumor were stained by FH4 (defining dimeric Le(x)), while other complementary areas were strongly stained, in a mutually exclusive manner, by SH1 (defining Le(x)), AH6 (defining Le(y)), FH6 (defining sialosyl dimeric (Le(x)), or TKH2 (defining sialosyl-Tn). Some areas were stained by two or three of these antibodies. Comparisons of the mosaic-staining patterns with cytohistological properties of tumor cells within specific areas suggested that the pattern of antigen expression is correlated with degree of differentiation; e.g., poorly-differentiated cells with severe dysplasia did not express high levels of Le(x) or Le(y) but did express sialyl-Le(x) or dimeric Le(x); on the other hand, moderately or well-differentiated tumor cells in some areas expressed high levels of Le(x) or Le(y) but lower levels of sialyl-Le(x). Areas showing strong expression of sialyl-Tn in their secretions were consistently correlated with presence of well-differentiated tumor cells, whereas secretions from normal mucosae were consistently characterized by lack of sialyl-Tn expression. It is postulated that the original in situ tumors (which had homogeneous glycosylation patterns) evolved into several spatially discrete cell populations displaying different degrees of glycosylation, reflecting stages of tumor cell differentiation and progression.