Anti-CD3 induces bi-phasic apoptosis in murine intestinal epithelial cells: possible involvement of the Fas/Fas ligand system in different T cell compartments

Recent studies have suggested that Fas-mediated apoptosis is involved in the pathogenesis of intestinal injury. In this study, we determined the role of Fas/Fas ligand (FasL) interactions in different T cell compartments using a murine model of small intestinal injury. An intraperitoneal injection of 145-2C11 (anti-CD3) antibody into C3H/HeN, BALB/c and MRL mice induced mucosal flattening and rapid, bi-phasic intestinal epithelial cell (IEC) apoptosis, which was detected by conventional light and electron microscopy and by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling. In the first, early phase, villous apoptosis was observed up to 4 h after injection, and in the second, later phase, apoptotic crypt cells gradually accumulated for up to 24 h. The early and later phases of apoptosis were reduced in lpr/lpr and nude mice compared with those in control strains. In addition, the kinetics of Fas-mediated killer activity induced by the antibody injection were different between intestinal intraepithelial lymphocytes (IEL) and splenocytes (SPL) and seemed to correlate with the bi-phasic occurrence of the apoptosis. Finally, the transfer of intestinal IEL from euthymic to nude mice induced both phases of apoptosis, whereas SPL induced the second phase's crypt apoptosis only by the antibody injection. Together, these results suggest the involvement of Fas-mediated killer activity of thymus-derived T cells in different compartments. Namely, T cell populations in different compartments are differentially involved in the induction of IEC apoptosis and contribute to the complex pathogenesis of immune-mediated intestinal injury in which Fas/FasL interactions may play a critical role.     

Survival of patients with HTLV-I-associated lymph node lesions

Adult T-cell leukaemia/lymphoma (ATLL), is a malignant condition associated with human T-cell leukaemia virus type I (HTLV-I). Usually, although not uniformly, histopathological examination of the lymph nodes shows a pleomorphic type. In addition, some patients with pre-overt ATLL show a Hodgkin's disease-like morphology and lymph nodes in non-neoplastic carriers show features of lymphadenitis. To characterize further the clinicopathological features of HTLV-I-associated lymphadenopathy, the histopathological features of the lymph nodes of 289 patients were classified into five types: lymphadenitis ( n=14), Hodgkin's-like (Hodgkin's) ( n=18), pleomorphic (medium and large cells) ( n=219), pleomorphic small cell ( n=11), and anaplastic large cell (ALC) ( n=27). Survival data were analysed according to the histopathological features of the lymph nodes. The pleomorphic type, which showed typical features of ATLL, was associated with a highly aggressive course and an initially high mortality, followed by a rapid decrease in survival. This pattern was also observed in patients with the ALC type. All cases with lymphadenitis were still alive at the end of the study, while survival progressively decreased in the Hodgkin's type. The small cell type showed an initial rapid decrease in survival followed by a plateau. These results show that the survival trends of patients with pleomorphic and anaplastic lymph node lesions are similar to those with ATL lymphoma, while patients with the lymphadenitis type of lesion were considered to have a non-neoplatic status. There is at present no effective therapy for ATLL, but in the future, these classification and survival data might be useful for the selection of appropriate chemotherapeutic regimens for patients with ATLL.     

CHEMOTACTIC ACTIVITY FOR POLYMORPHONUCLEAR AND MONONUCLEAR LEUKOCYTES IN RHEUMATOID SYNOVIAL FLUIDS

In order to why polymorphonuclear leukocytes (PMNs) are predominant and mononuclear leukocytes (MNLs) are few in rheumatoid synovial fluids, chemotactic factor(s) for PMNs and MNLs were studied in the synovial fluids of rheumatoid arthritis (RA-SF) and osteoarthritis (OA-SF) using both Boyden's and agarose methods. The RA-SF showed strong chemotactic activity for human peripheral blood PMNs compared with non-rheumatoid OA-SF. The chemotactic activity for PMNs was well correlated with the number of PMNs in RA-SF, suggesting that it was a natural mediator for PMN emigration into rheumatoid joint cavity. The major chemotactic factor for PMN in RA-SF was of apparent molecular weight of 14,000 and its activity was suppressed to less than 10 percent by anti-C5a antibody, but it failed to show any anaphylatoxin activity which was an attribute of C5a. It was, therefore, suggested to be C5a-like molecule but not C5a itself. The possibility that the factor may be a C5a des-Arg was discussed. On the contrary, the chemotactic activity for MNLs was not found neither in RA-SF nor OA-SF. These findings may explain the fact that PMNs are predominant in rheumatoid synovial fluids.     

The structure of human metaphase chromosomes: its histological perspective and new horizons by atomic force microscopy

Studies on the structure of the human chromosome were reviewed from the histological perspective and discussed in connection with our recent findings obtained mainly by atomic force microscopy (AFM). In this paper, we introduce several hitherto known models of the high-order structure of the metaphase chromosome and discuss the actual structure of chromosomes in relation to such structures as spiral chromatids, chromosome bands, and chromosome scaffolds. In chromosomes treated with Ohnuki's hypotonic solution, the chromosome arms were elongated and showed a characteristic spiral pattern of chromatid fibers. On the other hand, alternating transverse ridges and grooves were clearly observed on the surface of chromosomes treated with 0.025% trypsin for G-banding, and these ridges and grooves corresponded to the dark and pale bands of G-banded chromosomes. Similar findings were also found in chromosomes treated with quinacrine mastards for Q-banding. Fibers bridging the gap between the sister chromatids were often observed in G/Q-banded chromosomes; these fibers tended to be restricted within the G/Q-positive portions, suggesting the presence of chromatin fibers bridging these regions. Based on these findings in conjunction with previous studies, we outlined the high-order structure of the human chromosome. Recent advances in nanotechnology have provided new AFM techniques for the imaging and handling of materials at nano-scale resolution. Application of these techniques to chromosome research is expected to provide valuable information on the chromosome structure in relation to its function.     

Molecular analysis of structural protein genes of the yamagata-1 strain of defective subacute sclerosing panencephalitis virus. II. Nucleotide sequence of a cDNA corresponding to the P plus M dicistronic mRNA

The nucleotide sequence of a cloned cDNA corresponding to the P+M dicistronic mRNA of a subacute sclerosing panencephalitis (SSPE) virus was determined and compared with data of measles virus (MV). The dicistronic mRNA of the SSPE virus consisted of the 3 proximal 626 nucleotides of P mRNA, intercistronic trinucleotides, a full length of M mRNA, and 75 poly A nucleotides. The part encoding the P protein had a high homology to MV, except at the noncoding region. The terminating consensus sequence of the P gene and the intercistronic trinucleotides of the SSPE virus were CTAC(A)₆ and CCT; in MV they are TTAT(A)₆ and CTT, respectively. In the M gene, the starting consensus sequence was exactly the same as MV, but at the 5 proximal end, one third of this gene was different: The first ATG codon of the MV M gene signaling opening of the reading frame was changed to ACG in the SSPE virus and one long open reading frame started from the third ATG codon. The stop codon (TAG) of the MV M gene was also changed to CAG in the SSPE virus. Thus, the deduced SSPE-virus M protein lacked 50 amino acids at the amino terminal and had 15 extra amino acids at the carboxyl end when compared with the MV M protein.     

Atomic force microscopy for imaging human metaphase chromosomes

The present study introduces the principle of atomic force microscopy (AFM) and reviews our results of human metaphase chromosomes obtained by AFM. AFM imaging of the chromosomes revealed that the chromatid arm was not uniform in structure but had ridges and grooves along its length, which was most prominent in the late metaphase. The arrangement of these ridges and grooves was roughly symmetrical with the counterpart of the paired sister chromatids. AFM imaging of banded chromosomes also showed that the ridges and grooves were related to the G/Q-positive and G/Q-negative bands, respectively. At high magnification, the chromatid was seen to be produced by the compaction of highly twisted chromatin fiber loops, and its compaction tended to be stronger in the ridged regions of the chromosomes than in the grooved regions. Our AFM studies also showed the presence of catenation of chromatin fibers between the ridged portions of the chromatid in the late metaphase. Thus, AFM is useful for obtaining the three-dimensional surface topography not only in ambient conditions but also in physiological liquid conditions, and is expected to be an attractive tool for investigating the structure of chromosomes.     

Comparative study of a novel selective urate reabsorption inhibitor “dotinurad” among patient groups with different stages of renal dysfunction

Clinical and Experimental Nephrology - Dotinurad is a selective urate reabsorption inhibitor (SURI), which selectively inhibits URAT1 to lower serum uric acid levels in patients with hyperuricemia....     

Investigation of the renal injury caused by liver ischemia-reperfusion in rats

To explain the mechanism of renal injury caused by liver ischemia-reperfusion, we investigated biochemical and morphological changes in the liver and kidney in rats. After reperfusion following 60 min of liver ischemia, numerous changes were found. The level of serum transaminases and lipid peroxide formation in the liver tissue increased significantly. Electron microscopic studies revealed that most of the hepatocytes had swollen mitochondria and clumping of the nuclear chromatin. The sinusoidal endothelium was disrupted and the sinusoidal lumen was filled with numerous erythrocytes. Blood endotoxin concentration, plasma lipid peroxide levels, and serum -glucuronidase activities were significantly higher than in the control group. Biochemical and morphological renal injury was also observed. Tissue lipid peroxide levels increased in both the kidney and the liver. Microscopic examination revealed damage to the renal tubules, including interstitial edema, dilatation of the lumen, and granular casts derived from necrotic cells in the proximal convoluted tubule. The levels of urinary N-acetyl--d-glucosaminidase (NAG) in the liver ischemia-reperfusion group were also higher than in the control group. These results suggest that the renal injury was caused by an increase in endotoxin, lipid peroxide, and lysosomal enzymes in the blood following the liver injury induced by the ischemia-reperfusion.     

Molecular basis of carotid body tumor and associated clinical features in Japan identified by genomic,immunohistochemical, and clinical analyses

Carotid body tumor (CBT) is classified as a paraganglioma (PGL). Here, we report the genetic background, protein expression pattern, and clinical findings of 30 Japanese CBT cases. Germline pathogenic or likely pathogenic (P/LP) variants of genes encoding succinate dehydrogenase subunits (SDHs) were detected in 15 of 30 cases (50%). The SDHB variants were the most frequently detected, followed by SDHA and SDHD variants. One case with SDHAF2 variant was bilateral CBT, and other two multiple PGL cases were not detected P/LP variants. The three cases with germline variants that could be tested did not have somatic P/LP variants of the same genes. Immunohistochemical analysis showed negative SDHB signals in CBT tissues in five cases with germline P/LP variants of SDHB, SDHD, or SDHA. In addition, SDHB signals in CBT tissues were negative in four of nine cases without germline P/LP variants of SDHs. These findings suggest the involvement of unidentified molecular mechanisms affecting SDHs.     

Use of the sandwich method with an ultra-high-molecular-weight polyethylene prosthesis and Marlex mesh in sternal reconstruction: Report of a case

A 52-year-old Japanese man with a slow-growing chondroma originating from the sternal bone was referred to our hospital. A subtotal resection of the sternum was performed, hereafter termed the sandwich method, and an originally designed prosthesis made from ultra-high-molecular-weight polyethylene and Marlex mesh was used for reconstruction. The postoperative course was uneventful without any symptoms due to paradoxical movement of the chest or regional abscess, and no disturbance in the movement of the upper limbs, such as a surgical sequelae, was observed.