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Biomedical subjects

S Taniguchi

Publications and source records attributed to S Taniguchi.

At least 109 records · Page 6Linked to original sources
PubMed2000

Regulation of shortening velocity by calponin in intact contracting smooth muscles.

To elucidate the function of calponin in intact contracting smooth muscle cells in vivo, we generated mice with a mutated basic calponin (h1) locus (Yoshikawa et al., Genes Cells 3, 685-695, 1998). Crossbridge cycling rates were estimated in aortic smooth muscle by the force redevelopment following an isometric step shortening as a function of time after K(+) depolarization. Evidence is presented that calponin is involved in the inhibition of shortening velocity in the tonic phase of contraction. The phosphorylation levels of myosin regulatory light chain and cytosolic calcium concentrations were not significantly different in paired comparisons between calponin-deficient (-/-) and wild-type (+/+) muscles at any time point after stimulation. The force-velocity relationships in vas deferens smooth muscle showed that the maximum shortening velocity of -/- muscle was significantly faster than that of +/+ muscle. There was no change in the length-force relationships in both -/- and +/+ muscles of aorta and vas deferens. The results suggest that calponin plays a role in regulation of the crossbridge cycling and that it may be responsible for reduced shortening velocity during a maintained contraction of mammalian smooth muscle.

Animals↗
PubMed2000

La autoantigen is cleaved in the COOH terminus and loses the nuclear localization signal during apoptosis.

La autoantigen is a 47-kDa nuclear protein that binds to nascent polymerase III transcripts and a number of viral RNAs. We show that La protein was cleaved to generate a 43-kDa fragment during apoptosis of human leukemic HL-60 cells treated with camptothecin or etoposide. Immunofluorescence microscopy showed that the La protein level was increased in the cytoplasm during apoptosis of HL-60 cells. In addition, UV irradiation of HeLa cells led to the cleavage and redistribution of La protein upon apoptosis. Several lines of evidence show that La protein is cleaved by caspase-3 or closely related proteases at Asp-374 in the COOH terminus. When the full-length (La) and COOH-terminally truncated (La delta C374) forms of La protein were expressed as fusion proteins with green fluorescence protein (GFP), GFP-La delta C374 was predominantly cytoplasmic, whereas GFP-La was localized in the nucleus. These results suggest that La protein loses the nuclear localization signal residing in the COOH terminus upon cleavage and is thus redistributed to the cytoplasm during apoptosis.

Animals↗
PubMed2000

Energy-gap dependence of photoinduced charge separation and subsequent charge recombination in 1,4-phenylene-bridged zinc--free-base hybrid porphyrins

A series of 1,4-phenylene-bridged ZP-HP hybrid porphyrins (ZP = zinc porphyrin, HP = free-base porphyrin) 1-8 ZH have been prepared in which an electron-donating ZP moiety is kept constant and electron-accepting HP moieties are varied by introducing electron-accepting substituents, so that the energy gap for charge separation, ZP-1HP*--> ZP(+)-HP-, covers a range of about 0.9 eV in DMF. Here selective excitation at the HP moiety was employed to avoid complication in the determination of electron transfer rates derived from energy transfer, 1ZP*-HP --> ZP-1HP*. Definitive evidence for the electron transfer has been obtained in three solvents (benzene, THF, and DMF) through picosecond-femtosecond transient absorption studies, which have allowed the determination of the rates of the photoinduced charge separation, ZP-1HP* --> ZP(+)-HP-, and subsequent thermal charge recombination ZP(+)-HP- --> ZP-HP. Dyad 1ZH in THF exhibits a biphasic fluorescence decay that indicates thermal repopulation of the ZP-1HP* from ZP(+)-HP-; this has been also supported by the transient absorption spectra. On this ground, the energy levels of the ZP(+)-HP- ion pairs have been estimated. Similar biphasic fluorescence decay has been observed for 5 ZH in benzene; this allows furhter estimation of the energy level of the ZP(+)-HP- ion pairs. The free-energy-gap dependence (energy-gap law) has been probed from the normal to the upper limit region for the rate of the charge separation alone, and only the inverted region for the rate of the charge recombination. It was not possible to reproduce both energy-gap dependencies of the charge separation and the charge recombination assuming common parameter values for the reorganization energy and electronic interaction responsible for the electron transfer with the classical Marcus equation. Although both energy-gap dependencies can be approximately reproduced by means of the simplified semiclassical equation, which takes into consideration the effect of the high-frequency vibrations replaced by one mode of averaged frequency, many features, which include the effects of solvent polarity, electron-tunneling matrix element, and so forth on the energy-gap law, are considerably different from those of the previous studied porphyrin-quinone systems with weaker inter-chromophore electronic interactions.

Journal Article↗
PubMed2000

Results from coronary artery bypass surgery combined abdominal aortic aneurysm repair.

OBJECTIVE: Complication from coronary artery disease is a major cause of mortality and morbidity in patients undergoing abdominal aortic aneurysm repair. We report our results from coronary artery bypass surgery performed in combination with abdominal aortic aneurysm repair in patients with coronary artery disease and abdominal aortic aneurysm, each being an indication for an emergency operation. METHODS: Seventeen patients underwent combined coronary artery bypass surgery and abdominal aortic aneurysm repair. The mean age of the patients was 67.6 +/- 5.2 years. Four had left main disease, 8 patients had triple-vessel disease, and 12 had a prior myocardial infarction. The average left ventricular ejection fraction was 0.49 +/- 0.13. The average abdominal aortic aneurysm diameter was 6.2 +/- 1.0 cm (range 4.5-8.0 cm). Thirteen patients underwent coronary artery bypass surgery followed by abdominal aortic aneurysm repair after discontinuation of cardiopulmonary bypass. In the remaining four patients, including one patient with severe left ventricular dysfunction, cardiopulmonary bypass was continued as a circulatory assist until the abdominal aortic aneurysm repair was completed. The left internal thoracic artery was used in 14 patients, and the right internal thoracic artery in one patient. RESULTS: Postoperative surgical complications occurred in three patients (bleeding in one patient requiring reoperation, abdominal subcutaneous wound infection in another and transient neural disorder in the others). There were no surgical or in-hospital death. There was no late cardiac complication and no late cardiac death after a mean of 29 months follow-up. CONCLUSIONS: We concluded that combined surgery was reasonable for selected patients with combined coronary artery disease and abdominal aortic aneurysm, each of which is an indication for an urgent operation. The aortic aneurysm repair during cardiopulmonary bypass for patients with severe left ventricular dysfunction was safe and effective.

Aged↗
PubMed2000

Intracellular pH regulatory mechanism in a human renal proximal cell line (HKC-8): evidence for Na+/H+ exchanger, CI-/HCO3- exchanger and Na+-HCO3- cotransporter.

In the present study we investigated whether an immortalized human renal proximal cell line, HKC-8, expresses a recently cloned Na+-HCO3- cotransporter (NBC-1) and, if so, which isoform (kNBC-1 from kidney or pNBC-1 from pancreas) is expressed in this cell line. Cell pH (pHi) measurements using a pH-sensitive fluorescence probe in the absence of HCO3-/CO2 revealed the presence of a Na+/H+ exchanger that required high concentrations of amiloride for full inhibition. In the presence of HCO3-/CO2 another pHi recovery process, dependent on Na+ but independent of Cl-, was identified. This process was electrogenic and was inhibited by 4,4'-diisothiocyanatodihydrostilbene-2,2'-disulphonic acid (DIDS), being consistent with the Na+-HCO3- cotransporter. In addition, the pHi responses to Cl- removal were compatible with the presence of a Na+-independent Cl-/HCO3- exchanger that was also inhibited by DIDS. Reverse transcriptase polymerase chain reaction (RT-PCR) using primers designed for specific and common regions detected mRNAs of both kNBC-1 and pNBC-1 and Western blot analysis confirmed the expression of NBC-1 protein. These results indicate that HKC-8 has transport activities similar to intact proximal tubules and also suggest that both kNBC-1 and pNBC-1 may contribute to the Na+-HCO3- cotransport activity in this cell line.

Acids↗
PubMed2000

Immunocytochemical analysis of cellular infiltrates in human appendicitis.

This study was conducted to determine the immunologic cellular composition in human appendicitis and its association with the development of perforated appendicitis. Appendiceal specimens from 27 patients with acute appendicitis were immunostained to detect lymphocyte surface markers. Moreover, the lymphocyte surface markers of peripheral blood were analyzed by laser flow cytometry in 12 patients. Helper T lymphocytes (CD4) were present in all the patients, while B lymphocytes (CD19), natural killer (NK) cells (CD56), and cytotoxic T lymphocytes (CD8) were present in 7 (70%), 10 (100%), and 9 patients (90%) with perforated appendicitis, and in 12 (63.2%), 10 (58.8%), and 6 (54.5%) patients without perforation, respectively. There were significant differences between the patients with a perforated appendix and those without perforation, in the positivity rate for CD8 and CD56 cells (P < 0.05). The number of cells positive for CD56, being NK cells, in the blood from the patients with perforation was significantly lower than that in the blood from those without perforation (P < 0.05). The infiltration of a greater number of cytotoxic T lymphocytes and NK cells was observed in the appendices from patients with perforated appendicitis than in those from patients with nonperforated appendicitis.

Adolescent↗
PubMed2000

The occurrence of a strangulated ileus due to a traumatic transmesenteric hernia: report of a case.

We report herein the case of a 6-year-old boy in whom a strangulated ileus was caused by a traumatic transmesenteric hernia. The boy had fallen from his bicycle and suffered a severe blow to the abdomen. Abdominal pain and vomiting developed 10 h after the accident and he was admitted to our hospital. Abdominal ultrasonogram and computed tomogram demonstrated ascites, intestinal wall thickening with fluid, and an engorged radiating mesenteric vasculature. Thus, an emergency laparotomy was performed which revealed bloody ascites, a strangulated ileus, and torsion with a transmesenteric hernia. The necrotic intestine was resected and an anastomosis was performed. Macroscopic and microscopic findings revealed a traumatic mesenteric rent. The unusual presentation of this case is discussed.

Abdominal Injuries↗
PubMed2000

Differential expression of cytokeratin after orthotopic implantation of newly established human tongue cancer cell lines of defined metastatic ability.

Two human tongue squamous cell carcinoma cell lines, SQUU-A and SQUU-B, were established from the same patient. Cervical lymph node metastasis was detected in the mice orthotopically implanted with SQUU-B (86.7%, 13/15), but not in those with SQUU-A (0/13). Histologically, SQUU-B showed invasive growth and intravasation in the tongue, whereas SQUU-A simply demonstrated expansive growth without intravasation. By Western blot analysis, nonmetastatic clone SQUU-A expressed cytokeratin (CK)13/4, 14, 16/6, 18/8, and 19, whereas a high metastatic clone SQUU-B expressed CK18/8 and 19. The reverse transcription-polymerase chain reaction technique showed that CK13/4 mRNA was expressed in both cell lines, but CK14 and 16 mRNA was expressed only in SQUU-A. CK13 was immunohistochemically expressed in both SQUU-A and SQUU-B transplanted into the tongues of nude mice; CK14 and 16 were detected in SQUU-A of the tongues, but not in SQUU-B. As seen in SQUU-B cell line, SQUU-B of the cervical lymph node metastasis did not exhibit CK13, 14, or 16. These results suggest that the loss or down-regulation of CK13, 14, or 16 is related to the invasive and metastatic ability of cancer. The cytoskeletal system is thus considered to be closely related to the malignant phenotype.

Animals↗
PubMed2000

In vivo gene gun-mediated transduction into rat heart with Epstein-Barr virus-based episomal vectors.

BACKGROUND: Gene guns have been used to transfer genes into various organs, but there has been no report of successful gene gun-mediated gene transfer into the heart. In this study, we assessed the possibility of gene therapy using a gene gun and an episomal plasmid vector. METHODS: Gene transfer was performed using two sizes of gold particles and two plasmids (an episomal vector and a conventional plasmid vector). From the first to eighth week after the bombardment, rats were sacrificed. The excised hearts were subjected to X-gal staining and histologic examination. To ensure that plasmid was not distributed to organs other than the heart, the presence of the beta-gal sequence was examined by polymerase chain reaction analyses. RESULTS: Gene expression persisted for 6 weeks. The episomal vector apparently contributed to long-lasting expression. Infiltration of monocytes or leukocytes was very faint. The beta-gal DNA was detected in bombarded hearts but not other organs. CONCLUSIONS: Gene gun-mediated transfer of the episomal vector into beating heart may provide a simple, efficient, and useful strategy for gene therapy.

Animals↗
PubMed2000

Effects of warm ischemia and cryopreservation on cartilage viability of tracheal allografts.

BACKGROUND: For clinical use of a cryopreserved tracheal allograft, it is important to evaluate cartilage viability. We assessed cell viability of the cartilage in a cryopreserved tracheal allograft by measurement of Na2 35SO4 incorporation. We also investigated the effects of warm ischemic time on tracheal cartilage viability. METHODS: The tracheas from Lewis rats were harvested and preserved at different warm ischemic times from cardiac death to preservation (0, 1, 2, 4, 6, 9, and 12 hours, each group n = 8). The cartilage was labeled with 4 muCi/mL of Na2 35SO4. The specimen was hydrolyzed in 0.5 mol/L NaOH, and a solution of the extracts was then counted by liquid scintillation counter. Tracheas were transplanted into Brown Norway rats. RESULTS: 35Sulfur incorporation in the cartilage decreased as warm ischemic time increased. In addition, 35Sulfur incorporation decreased from 76% to 67% after cryopreservation. Histologic examinations of the normal tracheal cartilage before preservation and after thawing were done in all the groups. After transplantation, the cartilage had severe fibrous changes, and its layer was almost nonobservable in the 9- and 12-hour groups. CONCLUSIONS: The viability of the tracheal cartilage decreased with warm ischemic time and from 76% to 67% after cryopreservation. In the rat tracheal transplantation model, a cryopreserved tracheal allotransplant could be done safely with a graft that was cryopreserved within 6 hours of warm ischemic time.

Animals↗
PubMed2000

The db/db mouse, a model for diabetic dyslipidemia: molecular characterization and effects of Western diet feeding.

Diabetic dyslipidemia is a major factor contributing to the accelerated atherosclerosis in type 2 diabetes mellitus. Although several mouse models are available, the plasma lipoproteins in response to diet have not been fully characterized in these animals. In this study, we have characterized the plasma lipoproteins and related apolipoproteins, as well as the vascular lipases, in diabetes (db/db) mice and their nondiabetic controls (+/?) in the C57BL/KsJ strain. Within 6 weeks of age, db/db mice developed significant obesity, fasting hyperglycemia, and hyperinsulinemia. By FPLC analysis, db/db mice showed a prominent peak in the low-density lipoprotein (LDL) range that was absent in +/? mice, although high-density lipoprotein (HDL) was the predominant species in both groups of animals. Postheparin lipoprotein lipase (LPL) activity in db/db mice was 28% of the level in +/? mice. Upon feeding a human-like 0.15% (wt/wt) cholesterol and 21% (wt/wt) fat "Western" diet, db/db mice developed elevated plasma cholesterol, accompanied by an exaggerated apolipoprotein E (apoE) response compared with +/? mice. FPLC analysis showed that the marked hypercholesterolemic response in db/db mice was the result of a massive increase in the LDL region, which overshadowed a moderate increase in HDL. We next isolated lipoproteins by ultracentrifugation and characterized them by nondenaturing gradient gel electrophoresis. With regular chow, db/db mice had almost exclusively small dense LDL with a peak size at 21.4 nm, as compared with 26.6 nm in nondiabetic controls. On the Western diet, the small dense LDLs persisted but larger particles also appeared in db/db mice, whereas the size distribution in +/? mice was unchanged by the diet. Our results suggest that db/db mice fed a Western diet have a plasma lipoprotein phenotype that shows some similarities to that in patients with type 2 diabetes mellitus, and that db/db mice are a useful model to study the pathogenesis and treatment of diabetic dyslipidemia.

Age Factors↗
PubMed2000

Galloylglucoses and riccionidin A in Rhus javanica adventitious root cultures.

Adventitious root cultures of Rhus javanica L. produced large amounts of galloylglucoses (gallotannins) and an anthocyanidin, riccionidin A, formerly found only in liverworts. Production of both galloylglucoses and riccionidin A in the adventitious root culture system was suppressed by light. The Rhus root culture showed the highest productivity for those secondary metabolites in a modified Linsmaier-Skoog (LS) liquid medium containing 30 mM NH4+ and 30 mM NO3- as nitrogen sources in the presence of 10(-6) M 3-indoleacetic acid (IAA).

Anthocyanins↗
PubMed2000

Scleroderma-like reaction induced by uracil-tegafur (UFT), a second-generation anticancer agent.

UFT, a combination of uracil and tegafur, is a second-generation anticancer agent. UFT has been used in Japan, other Asian countries, South America, and Russia. Recently, UFT has been extensively studied for colorectal, pancreatic, and various types of cancer in North America and Europe, especially with leukovorin. We report a case of a scleroderma-like reaction induced by long-term administration of UFT. This is the first report of UFT-induced scleroderma-like reaction.

Antimetabolites, Antineoplastic↗
PubMed2000

Are nitrite/nitrate (NOx) levels elevated by inhalation injury?

The relationship between airway burn and nitric oxide (NO) levels in the early burn stage was investigated by quantifying nitrite/nitrate (NOx), which are the final metabolites of NO, in 22 burn patients. Although total body surface area (TBSA) and burn index (BI) were significantly higher in patients with airway-burn than in patients without airway burn (P=0.0347 and 0.0422, respectively), no significant difference in NOx levels was observed between the two groups (P=0.6196). The NOx levels were found to correlate significantly with TBSA (r=0.4775, P=0.0246). A significant correlation was also noted between the NOx levels and BI (r=0.4391, P=0.0409). These results suggest that NO reflects the intensity of inflammation in the early burn stage, but that excessive NO formation is unlikely to be induced by stress, such as that caused by airway burn.

Adult↗