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J Sasaki

Publications and source records attributed to J Sasaki.

At least 109 records · Page 6Linked to original sources
PubMed1998

The transducer protein HtrII modulates the lifetimes of sensory rhodopsin II photointermediates.

We studied the photochemical reaction cycle of sensory rhodopsin II (SRII) by flash photolysis of Halobacterium salinarum membranes genetically engineered to contain or to lack its transducer protein HtrII. Flash photolysis data from membranes containing HtrII were fit well in the 10 micros-10 s range by three rate constants and a linear unbranched pathway from the unphotolyzed state with 487 nm absorption maximum to a species with absorption maximum near 350 nm (M) followed by a species with maximum near 520 nm (O), as has been found in previous studies of wild-type membranes. Data from membranes devoid of HtrII exhibited similar M and O intermediates but with altered kinetics, and a third intermediate absorbing maximally near 470 nm (N) was present in an equilibrium mixture with O. The modulation of SRII photoreactions by HtrII indicates that SRII and HtrII are physically associated in a molecular complex. Arrhenius analysis shows that the largest effect of HtrII, the acceleration of O decay, is attributable to a large decrease in activation enthalpy. Based on comparison of SRII photoreactions to those of sensory rhodopsin I and bacteriorhodopsin, we interpret this kinetic effect to indicate that HtrII interacts with SRII so that it alters the reaction process involving deprotonation of Asp73, the proton acceptor from the Schiff base.

Archaeal Proteins↗
PubMed1998

Thyroglossal duct remnant penetrating the hyoid bone--a case report.

Examination of the thyroglossal duct (TGD) in a senile patient with a thyroglossal duct cyst (TGDC), as well as in children, is very valuable in understanding the pathology of TGDC. The precise anatomy of TGDC was studied in a specimen obtained from a 59-year-old man using three-dimensional reconstruction. The authors found the TGD penetrated the hyoid bone. This pathological evidence has not previously appeared in the literature. Penetration of the hyoid bone by the TGD is the result of a forward growth of the hyoid bone after development of a TGD, which had appeared ventral to the hyoid bone. In this gradual forward growth, the hyoid bone had first started to press against, before eventually engulfing, the TGD.

Bone Diseases↗
PubMed1998

Use of a surrogate aerosol in a preliminary screening for the potential carcinogenicity of coal coated with No. 6 fuel oil.

Coal, which contains significant amounts of water, can be ground and dried to produce an efficient fuel for electric power plants; however, spontaneous combustion can occur in the dried coal. Liquid petroleum hydrocarbons inhibit this combustion, but not all petroleum streams are effective. No. 6 fuel oil, a readily available and inexpensive stream, provides an effective coating, but the carcinogenic potential of coal particles treated with No. 6 fuel oil, which contains polynuclear aromatic hydrocarbons (PNAs), was undefined. As part of the assessment process, a series of studies was conducted to compare this treated coal with similar particles (petroleum coke) that had been tested by chronic inhalation in monkeys and rats. The amounts of PNAs in petroleum coke and treated coal were compared in extraction studies; the treated coal had only two-thirds of the organics extractable with benzene compared with coke and only 7% as much of the 3-7 ring PNAs, the likely tumorigenic compounds. In addition, the analytical profile of 3-7 ring PNAs was of lower molecular weights in the coal treated with fuel oil. The mutagenicity of extracts from treated coal was much less than with petroleum coke and markedly less than that of No. 6 fuel oil itself. The percutaneous absorption of 3H-benzo(a)pyrene from both particles and from their benzene extracts, as measured in vitro, was approximately eight times greater with petroleum coke than with treated coal. Based on these preliminary results, there is no evidence suggesting that the treated coal would pose any greater carcinogenic risk than petroleum coke.

Aerosols↗
PubMed1998

Blood pressure lowering effect of low intensity aerobic training in elderly hypertensive patients.

PURPOSE: The purpose of this investigation was to determine the effect of 9 months of low intensity aerobic training on blood pressure in elderly hypertensive patients who were receiving antihypertensive medication. METHODS: The training group (N = 13; mean age 75.4 +/- 5.4 yr) agreed to take part in physical training using a treadmill with an exercise intensity at the blood lactate threshold (LT) for 30 min three to six times a week for 9 months. The rest (N = 13; mean age 73.1 +/- 4.2 yr) served as controls. RESULTS: The resting systolic (-15 +/- 8 mm Hg), mean (-11 +/- 6 mm Hg), and diastolic blood pressures (-9 +/- 9 mm Hg) decreased significantly after 3 months of training and the blood pressure of all participants stabilized at a significantly lower level by the end of the study (9 months) in the training group, whereas no significant changes in blood pressure were found in the control group. Both the pretraining systolic and diastolic blood pressure of those recruited patients negatively correlated with those changes after the training (SBP: P < 0.01; DBP: P < 0.05, respectively). After 1 month of detraining in five patients, the blood pressure levels were similar to those in the pretraining state. The LT increased significantly in the training group (P < 0.01). CONCLUSION: In conclusion, an additional antihypertensive effect of mild aerobic training at the LT was confirmed in elderly patients receiving antihypertensive medication. The cessation of such training in five patients, however, resulted in a relatively rapid return to pretraining levels within a month.

Aged↗
PubMed1998

Taxonomic significance of 2,4-diaminobutyric acid isomers in the cell wall peptidoglycan of actinomycetes and reclassification of Clavibacter toxicus as Rathayibacter toxicus comb. nov.

An HPLC procedure which separates D- and L-amino acid isomers was applied to an analysis of peptidoglycan of 2,4-diaminobutyric acid (DAB)-containing actinomycetes. The cell wall peptidoglycans of species of the genera Agromyces, Clavibacter and Rathayibacter contain DAB and have been differentiated principally by their menaquinone profile. These peptidoglycans are known to be identical in structure, all being of the B2 gamma type, possessing both D- and L-DAB. The type strains of all the subspecies of Clavibacter michiganesis have D- and L-DAB in almost equal proportions in their cell wall peptidoglycan as previously reported. In contrast, the type strains of Clavibacter toxicus and all valid species of the genera Agromyces and Rathayibacter contain the L-isomer of DAB almost exclusively. This characteristic is in good agreement with phylogenetic analyses based on 16S rDNA sequences and menaquinone profiles. On the basis of these data, the transfer of Clavibacter toxicus to the genus Rathayibacter as Rathayibacter toxicus comb. nov. is proposed. The isomer profile of DAB is shown to be a good taxonomic marker to differentiate these genera.

Actinomycetales↗
PubMed1998

Description of four new species of the genus Kineosporia: Kineosporia succinea sp. nov., Kineosporia rhizophila sp. nov., Kineosporia mikuniensis sp. nov. and Kineosporia rhamnosa sp. nov., isolated from plant samples, and amended description of the genus Kineosporia.

Eleven motile spore-bearing actinomycetes were isolated from various plant samples and were studied to determine their taxonomic positions. The isolates showed colony appearance and morphology similar to those of the 'sporedome actinomycetes' previously described by L. G. Willoughby in 1969. Although the isolates showed variety in composition of isomers of 2,6-diaminopimelic acid in the cell walls and in whole-cell sugar patterns, all of the isolates were classified in the genus Kineosporia Pagani and Parenti 1978 emend. Itoh et al. 1989 on the basis of their morphological and other chemotaxonomic characteristics, i.e., menaquinone, phospholipid and cellular fatty acid compositions. This assignment to the genus was also supported by a phylogenetic analysis using the 16S rRNA gene sequences. By DNA-DNA hybridization experiment, five genospecies were recognized among the isolates, and one of them showed high levels with the type strain of the type species, Kineosporia aurantiaca, which is the sole member of the genus. These genospecies can be distinguished from each other by their cultural, physiological and biochemical characteristics, and the other four genospecies should be placed into four new species for which the names Kineosporia succinea (type strain I-273T = JCM 9957T), Kineosporia rhizophila (type strain I-449T = JCM 9960T), Kineosporia mikuniensis (type strain I-463T = JCM 9961T) and Kineosporia rhamnosa (type strain I-132T = JCM 9954T) are proposed.

Actinomycetales↗
PubMed1998

Significant correlation of nitric oxide synthase activity and p53 gene mutation in stage I lung adenocarcinoma.

Nitric oxide (NO) and its derivatives can directly cause DNA damage and mutation in vitro and may play a role in the multistage carcinogenic process. It has been reported that NO induces mutation in the p53 tumor suppressor gene; we therefore analyzed the relationship between NO synthase (NOS) activity and p53 gene status in early-stage lung adenocarcinoma. Surgical samples were classified into two categories: 14 lung adenocarcinomas with high NOS activity (>25 pmol/min/g tissue, category A), and 16 with low NOS activity (<25 pmol/min/g tissue, category B). A yeast functional assay for p53 mutations disclosed a red colony that corresponded to a mutation in the p53 gene in 8 cases (57.1%) in category A and 3 cases (18.8%) in category B, the frequency being significantly higher in the former (P<0.05). A p53 DNA sequence analysis revealed that 5 of the 8 p53 mutation-positive samples in category A had a G:C-to-T:A transversion, which is reported to be a major target of NO. The mechanism of carcinogenesis of adenocarcinoma is not fully understood, but these results suggest that an excess of endogenously formed NO may induce a p53 gene mutation containing mainly G:C-to-T:A transversion in the early stage of lung adenocarcinoma. Our results suggest that NO has potential mutagenic and carcinogenic activity, and may play important roles in human lung adenocarcinoma.

Adenocarcinoma↗
PubMed1998

Augmentation of mitochondrial reduced glutathione by S-adenosyl-L-methionine administration in ischemia-reperfusion injury of the rat steatotic liver induced by choline-methionine-deficient diet.

We examined whether warm ischemia-reperfusion (I/R) damage of the rat steatotic liver can be reduced by administration of S-adenosyl-L-methionine (SAMe). We examined the effect of SAMe on the mitochondrial reduced-glutathione (GSH) pool. Sixty minutes of partial left lobar vascular clamping followed by 2 h of reperfusion were employed for a model of hepatic warm ischemia. Either 5% dextrose or SAMe was injected intraperitoneally 2 h before I/R in steatotic rats (S-D5% or S-SAMe group). Serum liver enzyme concentrations 2 h after reperfusion were significantly lower in the S-SAMe group than in the S-D5% group. The cytosolic and mitochondrial GSH concentrations after I/R were significantly higher in the S-SAMe group than in the S-D5% group (p < 0.05). The cytosolic and mitochondrial oxidized-glutathione/GSH ratios after I/R were significantly greater in the S-D5% group than in the S-SAMe group (p < 0.01). The adenosine triphosphate concentration was higher in the S-SAMe group than in the S-D5% group (p = 0.0515). These results show that hepatocellular and mitochondrial oxidative stress after I/R in the steatotic liver can be reduced by administration of SAMe. The results also show that mitochondrial function and hepatocellular integrity can be restored by administration of SAMe in steatotic rats.

Animals↗
PubMed1998

A novel homozygous missense mutation in the apo A-I gene with apo A-I deficiency.

We analyzed the genetic defect in a 67-year-old Japanese male patient with apolipoprotein (apo) A-I and high density lipoprotein (HDL) deficiencies, corneal opacities, and coronary artery disease. The plasma concentrations of apoA-I and HDL cholesterol were 2.9 to 7.3 mg/dL and 0.08 to 0.19 mmol/L, respectively. The lecithin:cholesterol acyltransferase (LCAT) activity and cholesterol esterification rate were <40% of normal control values. LCAT mass was 550% of normal control. Sequence analysis of polymerase chain reaction-amplified DNA of the proband's apoA-I gene showed a homozygous T-to-A transition resulting in the substitution of Val 156 with Glu (apoA-I Oita). Direct sequencing of samples obtained from other family members showed that the brother was homozygous, whereas the son was a heterozygous carrier of apoA-I Oita. The heterozygote for apo A-I Oita showed nearly 60% of normal apoA-I and normal HDL cholesterol levels. In vivo turnover studies in rabbits demonstrated that the variant apoA-I was rapidly cleared from plasma compared with normal human apoA-I. Our data suggest that the Val156Glu substitution is associated with apoA-I and HDL deficiency, partial LCAT deficiency, and corneal opacities and that Val156 of apoA-I may play an important role in apoA-I function.

Aged↗
PubMed1998

[Surgery for the treatment of infective endocarditis in the active and inactive stages].

Twenty-eight patients (16 M, 12 F, age 11 approximately 72 yr, mean 52.8 yr) underwent surgery for infective endocarditis. Of the 27 patients, 16 were in the active stage and 11 were in the inactive stage. In patients in the active stage, aortic valve replacement (AVR) was performed in 5, mitral valve replacement (MVR) in 7, AVR + MVR in 1, AVR + MVR + tricuspid valve plasty (TVP) in 1 and other procedures in 2. In patients in the inactive stage, AVR was performed in 3, MVR in 4, AVR + MVR in 2, and other procedures in 2. Causative organisms were detected in 56.3% of the patients in the active stage and 54.5% in the inactive stage. Also in patients in the active stage, infection was not prolonged. No deaths occurred among patients in the inactive stage but five patients (31%) died postoperatively; 4 of the five also died, for had severe heart failure before surgery, three died of multiple organ failure and one died of subarachnoid hemorrhage due to infective aneurysm. We recommend surgery for the treatment of infective endocarditis even in the active stage before emergence of heart failure.

Adolescent↗
PubMed1998

[Tangier disease].

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Apolipoprotein A-I↗
PubMed1998

Semiquantitative bacteriology of closed odontogenic abscesses.

Pus samples from twenty-three dentoalveolar abscesses were collected by needle aspiration and examined by direct inoculation technique using 6 different aerobic and anaerobic agar plates. For aerobic culture, sheep blood agar and chocolate agar (Kyokuto Pharmaceutical Co., Tokyo, Japan) were used. For anaerobic culture, four different media, 1) brucella HK agar with hemolyzed rabbit blood and defibrillated sheep blood, 2) paramomycin-vancomycin brucella HK agar with hemolyzed rabbit blood, 3) phenylethyl alcohol brucella HK agar with hemolyzed rabbit blood, 4) bacteroides bile esculin agar (Kyokuto Pharmaceutical Co., Tokyo, Japan) were prepared in an anaerobic jar prior to inoculation. The aerobic agar plates were incubated for 24 h at 37 degrees C, and the anaerobic plates at least 48 h at 37 degrees C in anaerobic jars. From 23 closed odontogenic abscess samples, a total of 112 bacterial strains were isolated; 81 strains (72.3%) were strict anaerobes, and 31 strains (27.7%) were aerobes. The mean number of bacterial strains per positive sample was 4.86. Oral Streptococci, Prevotella, Fusobacterium, Peptostreptococcus and Veillonella were common isolates. The combination of Oral Streptococci and Prevotella was found in 11 patients (47.8%), and that of Prevotella and Peptostreptococcus in 12 patients (52.2%). The present study demonstrated that closed odontogenic abscesses are polymicrobial infections by aerobes and anaerobes. Application of a direct inoculation technique for bacterial culture made it possible to isolate more anaerobes than our commonly used technique using transport medium and to delineate the semiquantitative bacteriology of closed odontogenic abscess.

Acute Disease↗
PubMed1998

[Evaluation of hepatic arterial infusion chemotherapy using reservoir for liver metastases from gastric cancer].

UNLABELLED: We evaluated the results of hepatic arterial infusion chemotherapy (HAIC) using implantable reservoir for gastric cancer patients with unresectable liver metastases. Twenty-eight patients (19 with synchronous liver metastases, 6 patients with recurrent hepatic tumors, and 3 patients with high risk factors of liver recurrence after curative surgery) were treated with HAIC. The canula was inserted into the hepatic artery during primary surgery for 19 patients and during angiography for 7. The combination of anti-cancer drugs, such as, MMC + 5-FU (6 cases), ADM + 5-FU (14 cases), 5-FU + ADM + MMC (5 cases), and CDDP (3 cases) was administered by the intra-arterial route to out-patients every one or two weeks. RESULTS: The response rate of the metastatic liver foci in evaluable patients was 32.0% (1 CR + 7 PR/25). The median survival time (MST) of all patients was 294 days, and there were only two 5-year survivors treated to prevent recurrence. The 2-year survival after HAIC was 10.5% for the synchronous liver metastatic group and 53.3% for the metachronous group. The MST of responders was 94 days longer than that of non-responders, but there was no significant difference statistically. The remote survival of the patients whose palliative factors were liver metastases alone was significantly better than that of the patients with hepatic and extrahepatic palliative factors: the MST and 1-year survival was 329 days and 140 days, and 17.9% and 13.3%, respectively (p < 0.05). In conclusion, the clinical effect of HAIC was not sufficient. But the improvement of survival among patients without extrahepatic lesions as a palliative factor, and preventive HAIC was recommended.

Adult↗