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Biomedical subjects

S Sekiguchi

Publications and source records attributed to S Sekiguchi.

244 records · Page 14Linked to original sources
PubMedDate not supplied

Beneficial effect of FR183998, a Na+/H+ exchanger inhibitor, on porcine pancreas allotransplantation retrieved from non-heart-beating donors.

Activation of Na(+)/H(+) exchanger (NHE) may have an important role in the ischemia/reperfusion injury by producing intracellular calcium overload. Recent studies have shown a beneficial effect of an NHE inhibitor on the ischemia/reperfusion injury in the heart. In this study, we examined the effect of FR183998, a potent NHE inhibitor, in porcine pancreas allotransplantation from non-heart-beating Landrace pig donors (NHBDs). The four experimental groups included: untreated with no preservation (group 1; n = 3), treated with no preservation (group 2; n = 5), untreated with preservation (group 3; n = 6), and treated with preservation (group 4; n = 4). The preservation was made in ice-cold University of Wisconsin (UW) solution for 24 hours. The groups treated received 1 mg/kg FR183998 before donor cardiac arrest and 10 mg in the UW solution flush in situ. Serum blood glucose, insulin, and amylase were measured daily. An intravenous glucose tolerance test (IVGTT) was performed on the postoperative day (POD) 7 when pigs were sacrificed for histological examination. Graft survival rates on that day in groups 1,2,3, and 4 were 3 of 3; 5 of 5; 3 of 6; and 4 of 4, respectively. The mean K values of IVGTT in groups 3 and 4 were 0.78 +/- 0.10 and 1.27 +/- 0.16, respectively, which were significantly different (P < .05). Upon histological examination, pancreatic tissue in group 3 showed more severe edema and necrosis than other groups. FR183998 may be considered beneficial for ischemia/reperfusion injury to pancreatic grafts from NHBDs.

Adenosine↗
PubMedDate not supplied

Excessive portal flow causes graft nonfunction in small size liver transplantation: an experimental study in pigs.

We investigated the effects of portocaval shunt (PCS) on excessive portal flow in producing sinusoidal microcirculatory injury in small-for-size liver transplants in pigs. The posterior segment of a whole liver (25%) was transplanted orthotopically. The pigs were divided two groups: group A, graft with PCS (n = 11), and group B, graft without PCS (n = 11). The PCS was a side-to-side anastomosis of the portal vein and the inferior vena cava. In group A, eight pigs survived for more than 4 days; all pigs except for one died of graft nonfunction within 24 hours in group B. The portal flow after reperfusion decreased in group A, but increased about three times greater in group B than that before the operation (P < .01). In group B, destruction of the sinusoidal lining and bleeding in the periportal areas were observed after reperfusion, findings that were not recognized in group A. These results suggest that graft nonfunction after small-for-size liver transplantation may be attributable to excessive portal flow producing sinusoidal microcirculatory injury.

Animals↗
PubMedDate not supplied

A trimmed viral cap-independent translation enhancing sequence for rapid in vitro gene expression.

We prepared a short (29 nucleotides) 5' UTR that enhanced cap-independent translation in a wheat germ translation system by trimming the tobacco etch virus 5' UTR. The trimmed sequence, designated as TE(37-65), was obtained from a conserved region among several potyviruses. The productivities of uncapped reporter mRNAs carrying the TE(37-65) sequence were comparable to those of capped counterparts, in that 5-20 microg of proteins were synthesized per 1 mL of translation reaction mixture. The ribosome that entered onto the TE(37-65) sequence precisely initiated polypeptide synthesis at the defined initiation codon, which ensures rapid and efficient protein truncation analyses. Moreover, the TE(37-65) sequence is short enough to be involved in a PCR primer, which allows a simple method for rapid gene expression, i.e., PCR amplification of a target gene and succeeding in vitro transcription and translation. As a demonstration, the rapid in vitro expression of rice cDNAs using the TE(37-65) sequence was also performed.

5' Untranslated Regions↗
PubMedDate not supplied

An automated screening test for antibodies to human immunodeficiency virus-1.

An automated pretransfusion testing system was applied to HIV antibody screening by a gelatin particle agglutination (HIV-PA) test. The test conditions for the test, such as diluent, plate shape, and incubation time, were applicable not only for the HIV-PA test but also for other routine tests, including those for hepatitis B surface antigen and HTLV-1 antibodies. After a 60-minute incubation, the plates were read automatically and then were assessed visually. Tests with seropositive samples obtained from hemophiliacs and an HIV enzyme immunoassay (EIA) familiarization panel showed that the automated HIV-PA test was more sensitive than the EIA and did not show a false-negative result. Of 11,300 blood donors, 44 were positive by the automated test, and 51 were positive by the EIA. None of the blood donors was confirmed to be seropositive. Using the automated test, a large number of samples could be screened in a relatively short time without a significant increase of nonspecific reactions.

Agglutination Tests↗
PubMedDate not supplied

Characteristics of artificial red cells. Hemoglobin encapsulated in poly-lipid vesicles.

Artificial red cells (ARC) were prepared by encapsulation of purified human Hb with polymerizable phospholipid, 1,2-bis (2,4-octadecadienoyl)-sn-glycero-3-phosphocholine (DODPC). The polymerized lipid bilayer of the ARC produced great physical stability that could not be achieved using a non-polymerizable lipid for encapsulation. ARC showed no change in particle size or distribution or leakage of Hb after repeated freeze thawing (stability test). ARC have also been studied with regard to biocompatibility. The authors' results showed low acute toxicity (> 8000 mg/kg) and adequate blood compatibility. The result of transfusion tests in dogs showed that ARC had sufficient oxygen transporting capabilities.

Animals↗
PubMedDate not supplied

The impact of red cell substitutes on the blood service in Japan.

The total number of blood donors in 1994 was 6.6 millions, and 200 ml whole blood donation occupied 41.8% of all donations, whereas 400 ml and apheresis donations occupied 35.6%, 22.5% of all donations respectively. From the donated blood, about 8.35 million bags of blood components were prepared and were used for blood transfusion. Besides used as blood components, 720,000 L source plasma was used to produce plasma derivatives, and therefore Japan has achieved self-sufficiency in Factor VIII by donated blood. Blood transfusion has become quite safer but there are still risks of acquiring transfusion-associated GVHD(TA-GVHD) or infecting with HIV from blood in window period. To avoid adverse reactions of blood transfusion, the strategies for reducing homologous blood transfusion has been promoting. The use of red cell substitutes will be an option of using non-human derived substitutes toward "zero" adverse reaction of transfusion, and when red cell substitutes are accepted in Japan, they will be applied as the substitution to allogeneic blood transfusion below 1200 ml hemorrhage. They will also be applied as an alternation to and/or combination with allogeneic and autologous blood transfusion and the use of erythropoietin.

Blood Banks↗
PubMedDate not supplied

Sleep-wakefulness rhythms in mice after suprachiasmatic nucleus lesions.

The experiment was performed in order to investigate whether the suprachiasmatic nucleus is a potent circadian pacemaker also in mice. Cortical EEG activity and neck muscle EMG were continuously recorded in 19 albino mice under 12 h light-12 h dark cycles. Computer analysis revealed that after bilateral suprachiasmatic nucleus (SCN) lesions, the diurnal rhythm in slow wave sleep (SWS) and paradoxical sleep (PS) stages was completely eliminated although ultradian rhythms with 2-4 h periodicity persisted. However, the daily amount of either slow wave sleep or paradoxical sleep did not show any significant change after small hypothalamic lesions with a complete destruction of SCN.

Animals↗
PubMedDate not supplied

Prevalence of human T-cell leukemia virus type 1 (HTLV-I) in general inhabitants in non-adult T-cell leukemia (ATL)-endemic Hokkaido, Japan.

In contrast to adult T-cell leukemia (ATL)-endemic southwestern Japan, the northernmost island Hokkaido has a small number of ATL patients annually. In this study, we surveyed 32,587 healthy inhabitants throughout Hokkaido for antibodies to human T-cell leukemia virus type 1 (HTLV-I). Only 244 individuals (0.8%) were seropositive as HTLV-I carriers; 0.6% (123 of 19,512) in males and 0.9% (121 of 13,075) in females. In some areas, however, the inhabitants had relatively high seropositivity (> 2%). The highest rate was 5.2% with a cluster of ATL patients in a certain town of the Hidaka area near the Pacific Ocean, in southeast Hokkaido.

Adolescent↗
PubMedDate not supplied

Effects of methylglyoxal bis (cyclopentylamidinohydrazone) (MGBCP) on cell cycle progression in three human osteosarcoma cell lines.

Our previous experiments have indicated that the antitumor effects of a polyamine biosynthetic inhibitor, methylglyoxal bis(cyclopentylamidinohydrazone) (MGBCP), on human osteosarcoma cell lines such as MG-63, G-292 and HOS cells are obtained by its action depleting the cellular polyamine contents. In the present study, the effects of polyamine depletion by MGBCP on the cell cycle progression in these osteosarcoma cell lines were investigated by flow cytofluormetric analysis. MGBCP arrested the tumor cells at the G1 phase by preventing the G/S phase transition. Mitotic indexes (MIs) in these MGBCP-inhibited tumor cells were also decreased. These findings suggest that MGBCP suppresses the cell cycle progression in osteosarcoma MG-63, G-292 and HOS cells by inhibiting intracellular polyamine biosynthesis.

Antineoplastic Agents↗