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Biomedical subjects

M Sayama

Publications and source records attributed to M Sayama.

At least 19 recordsLinked to original sources
PubMed2000

Purification and biochemical properties of an N-hydroxyarylamine O-acetyltransferase from Escherichia coli.

The N-hydroxyarylamine O-acetyltransferase of Escherichia coli has been expressed as a histidine tagged fusion protein and purified using immobilized nickel column chromatography. The molecular mass of the histidine tagged N-hydroxyarylamine O-acetyltransferase was estimated to be 60.0 kDa by gel filtration and 34.0 kDa by SDS-PAGE and DNA sequence, suggesting that the native enzyme exists as homo dimer. The catalytic properties were investigated using o-aminobenzoic acid as a substrate. No difference in acetyltransfer activity was observed between histidine tagged protein and untagged enzyme. Kinetic studies indicated a ping-pong bi bi mechanism of the catalysis. Inhibition by N-ethylmaleimide and salicylic acid was competitive with o-aminobenzoic acid and non-competitive with acetyl-CoA.

Acetyl Coenzyme A↗
PubMed2000

Purification and DNA-binding properties of the cro-type regulatory repressor protein cng encoded by the Lactobacillus plantarum phage phi g1e.

The putative repressor protein Cng (10kDa on an SDS gel) for the lytic pathway of Lactobacillus plantarum phage φg1e was purified using the Escherichia coli Pt7 system, and its DNA-binding ability for the seven operator-like sequences, the GATAC-boxes (Gb1 to Gb7), was investigated in vitro. In gel-shift assays, Cng selectively bound to the DNA fragments containing the GATAC-box(es). In addition, DNase I footprinting analysis with supercoiled DNA demonstrated that Cng can specifically cover about a 25bp region centered around each of the GATAC-boxes, although two boxes, Gb4 and Gb6, were only partially protected. Moreover, protein crosslinking experiments using glutaraldehyde suggested that Cng most likely functions as a dimer. On the other hand, the binding ability of Cpg for the GATAC-boxes in supercoiled DNA was also examined under the same conditions as in Cng; unlike Cng, Cpg covered Gb4 and Gb6 completely sufficiently as well as the other five boxes. Thus, the present and previous [Kakikawa et al., Gene 215 (1998) 371-379; 242 (2000) 155-166] results indicate a possibility that the two proteins Cng and Cpg selectively bind to the GATAC-boxes that act as operators, and can decide between the lytic or lysogenic pathways through repression of the promoter activity of P(R) as well as P(L).

Bacteriophages↗
PubMed2000

Clinical efficacy of peritoneovenous shunting for the treatment of severe ovarian hyperstimulation syndrome.

We investigated prospectively the clinical efficacy of a newly developed continuous autotransfusion system of ascites (CATSA) without protein supplement in patients with severe ovarian hyperstimulation syndrome (OHSS). Peritoneovenous shunting was used to recirculate ascites. The CATSA was performed for 5 h at a rate of 100-200 ml/h once a day. Eighteen patients were treated with the CATSA (CATSA group) and 36 were treated with an intravenous 37.5 g/day of albumin supplement (albumin group). Hospital stay was significantly shorter in the CATSA group than in the albumin group (10.0 +/- 5.7 versus 13.9 +/- 6.2 days, P < 0.01). Haematocrit value reached <40% significantly earlier in the CATSA group (on hospital days 3.9 +/- 3.2 versus 5.9 +/- 2.5, P < 0.01). Using a single procedure, haemoconcentration, urinary output and pulse pressure were markedly improved in the CATSA group compared with the albumin group. Discomfort due to massive ascites diminished promptly and did not recur in nine of 18 CATSA group patients, whereas it persisted in all 36 patients in the albumin group. The serum concentration of protein was maintained in the CATSA group, whereas it did not increase in the albumin group despite daily supplementation with 37. 5 g of albumin. Apparent adverse effects of each procedure were not observed in either group. The mean values of several parameters in the serum pertinent to the coagulation-fibrinolysis system did not change significantly in either group after the procedure. It was concluded that the CATSA procedure expanded circulating plasma volume without exogenous albumin and appeared to lead to a prompt recovery from severe conditions of OHSS.

Adult↗
PubMed1999

Association of a decrease in antithrombin III activity with a perinatal elevation in aspartate aminotransferase in women with twin pregnancies: relevance to the HELLP syndrome.

BACKGROUND/AIMS: Decreased antithrombin III (AT-III) activity and/or thrombocytopenia associated with an elevated serum level of aspartate aminotransferase in late pregnancy can threaten the lives of both the mother and the fetus. We investigated whether antenatal declines in AT-III activity and the platelet count occur in late twin pregnancy and whether reduced AT-III activity and/or thrombocytopenia precedes an increase in the serum level of aspartate aminotransferase. METHODS: The platelet count, AT-III activity, and the serum level of aspartate aminotransferase were determined weekly or biweekly in 237 women with twin pregnancies in a longitudinal and partly prospective study. RESULTS: Both AT-III activity and the platelet count decreased gradually in the last month of pregnancy, irrespective of the presence or absence of clinical signs of pre-eclampsia. A perinatal elevation in aspartate aminotransferase occurred in 36 (15%) of 237 women. The risk of a perinatal elevation in aspartate amino-transferase increased as the antenatal AT-III activity and/or the platelet count decreased. Pre-eclampsia developed in 60 women (25%). The relative risk of a perinatal aspartate aminotransferase elevation (95% confidence interval) for the 60 women with pre-eclampsia, the 60 women with a platelet count < or = the 25th percentile (164 x 10(9)/1), and the 60 women with AT-III activity < or = the 25th percentile (76% of normal) was 1.9 (1.0 to 3.4), 4.1 (2.3 to 7.5), and 5.9 (3.2 to 11.1), respectively, compared with the remaining 177 women. CONCLUSIONS: AT-III activity and platelet count gradually decreased in the last month of twin pregnancies. A perinatal aspartate aminotransferase elevation was preceded by marked decreases in these parameters in women with twin pregnancies. The monitoring of AT-III activity and platelet count in women who exhibit a gradual decline in these parameters may help to avoid the development of severe HELLP syndrome.

Adult↗
PubMed1998

Mutagenicities of 2,4- and 2,6-dinitrotoluenes and their reduced products in Salmonella typhimurium nitroreductase- and O-acetyltransferase-overproducing Ames test strains.

Mutagenicities of 2,4- and 2,6-dinitrotoluene (2,4-and 2,6-DNT), and reduced metabolites formed by the incubation of 2,4- and 2,6-DNT with Salmonella typhimurium TA98, were tested using S. typhimurium YG strains possessing high level of nitroreductase (NR) and/or O-acetyltransferase (OAT) activities. All compounds tested showed greatest mutagenic activities toward strains YG1041 and YG1042, which possess high levels of NR and OAT activities. The relative mutagenic activities of 2,4-DNT and its related compounds toward YG1041 and YG1042 were aminonitrotoluenes<2,4-DNT<2,2'-dimethyl-5, 5'-dinitroazoxybenzene (2,2'-DM-5, 5'-DNAOB)4-hydroxylamino-2-nitrotoluene (4HA2NT)<<4, 4'-dimethyl-3,3'-dinitroazoxybenzene (4,4'-DM-3,3'-DNAOB), and aminonitrotoluenes (2A4AT, 4A2NT)<2,4-DNT<4HA2NT4,4'-dimethyl-3, 3'-dinitroazoxybenzene (4,4'-DM-3,3'-DNAOB)<2HA4NT, respectively. In addition, the relative mutagenic activities of 2,6-DNT and its related compounds toward YG1041 and YG1042 were 2, 6-DNT<2-hydroxylamino-6-nitrotoluene (2HA6NT)<2,2'-dimethyl-3, 3'-dinitroazoxybenzene (2,2'-DM-3,3'-DNAOB), and 2-amino-6-nitrotoluene (2A6NT)<2,6-DNT<2HA6NT, respectively. These results, together with previous findings, suggested that aminohydroxylamino dimethylazoxybenzenes or aminohydroxylamino dimethylazobenzenes produced either by the reduction of hydroxylaminonitrotoluenes or by the reduction of dimethyl dinitroazoxybenzenes are active metabolites responsible for the mutagenic activities of 2,4- and 2,6-DNT.

Acetyltransferases↗
PubMed1998

Lower risks of adverse outcome in twins conceived by artificial reproductive techniques compared with spontaneously conceived twins.

The outcomes of twins conceived by 136 women after medical assistance (MA) such as ovulation induction with or without assisted reproductive techniques, and twins conceived spontaneously (SP) by 72 women were compared. All 208 women were monitored from < 20 weeks gestation; they all delivered at > or = 24 weeks gestation. The chorionicity of the placenta was diagnosed antenatally and confirmed after delivery. There were 10 perinatal deaths; the physical and neurological status of the remaining 406 infants was assessed at 1 year of corrected age. There were no differences in gestational age at birth, the birth weights of the larger and smaller twins, the birth weight discordance, or the incidence of life-threatening major malformations between groups. Adverse infant outcomes, such as death, cerebral palsy and mental retardation occurred in nine (3.3%) of 272 MA twins compared with 12 (8.3%) of 144 SP twins (P < 0.05). The placenta was monochorionic in only three (2.2%) of 136 MA twin pregnancies compared with 41 (57%) of 72 SP twin pregnancies (P < 0.001). Of the 21 infants with adverse outcomes, nine had monochorionic placentas. Thus, the risk of an adverse outcome was 2.8-fold higher (95% confidence interval (CI) 1.2-6.4) in monochorionic twins than in dichorionic twins (10 versus 3.7%; P < 0.05). There was no difference in the incidence of adverse infant outcomes between SP (4.8%) and MA (3.4%) twins with dichorionic placentas. These findings suggest that ovulation induction in itself was not associated with an adverse outcome of twin pregnancies. The lower frequency of monochorionic placentas in MA twins may have been responsible for the lower risk of an adverse outcome in MA twins.

Birth Weight↗
PubMed1998

Synthesis of pyridinium dinitrobenzyl sulfates and potassium (dinitrobenzyl beta-D-glucopyranosid)uronates.

Sulfates and glucuronides of 2,4-dinitrobenzyl alcohol 1a and 2,6-dinitrobenzyl alcohol 1b, which are major or putative metabolites of 2,4-dinitrotoluene (2,4-DNT) and 2,6-dinitrotoluene (2,6-DNT), were synthesized from 1a and 1b by reaction with pyridinium sulfonate and methyl (2,3,4-tri-O-acetyl-alpha-D-glucopyranosyl)uronate bromide 3, respectively, as their pyridinium salts (2a, 2b) and potassium salts (6a, 6b). These conjugates are important for the study of the carcinogenicity of 2,4-DNT and 2,6-DNT.

Benzyl Alcohols↗
PubMed1997

Biliary excretion and microfloral transformation of major conjugated metabolites of 2,4-dinitrotoluene and 2,6-dinitrotoluene in the male Wistar rat.

1. Major biliary conjugates of the male Wistar rat dosed orally with 2,4-dinitrotoluene (2,4-DNT) or 2,6-dinitrotoluene (2,6-DNT) were examined by hplc using potassium 2,4-dinitrobenzyl glucuronide (potassium 2,4-DNB-G), potassium 2,6-dinitrobenzyl glucuronide (potassium 2,6-DNB-G), pyridinium 2,4-dinitrobenzyl sulphate (pyridinium 2,4-DNB-S) and pyridinium 2,6-dinitrobenzyl sulphate (pyridinium 2,6-DNB-S) as authentic compounds. Other metabolites were also examined by hplc. In addition, metabolites formed by incubation of potassium 2,4-DNB-G and potassium 2,6-DNB-G with rat intestinal microflora under nitrogen were examined by hplc. 2. Conjugates detected directly from bile following administration of 2,4-DNT and 2,6-DNT were 2,4-DNB-G and 2,6-DNB-G, which accounted for 35.0 and 51.5% of the administered dose respectively. No peaks corresponding to pyridinium 2,4-DNB-S and pyridinium 2,6-DNB-S were detected in bile samples. 3. 2-Amino-4-nitrotoluene, 4-amino-2-nitrotoluene, 2,4-diaminotoluene and 4-acetylamino-2-nitrobenzoic acid (0.02-0.12% of the dose excreted in 24 h), in addition to the known metabolites 2,4-dinitrobenzyl alcohol (2,4-DNB), 2,4-dinitrobenzaldehyde and 2,4-dinitrobenzoic acid (0.09-0.14%), were detected in ether extracts of bile of rat given 2,4-DNT. 2,6-Dinitrobenzyl alcohol (2,6-DNB), 2-amino-6-nitrotoluene and 2,6-dinitrobenzaldehyde (0.02-0.03%), which are known metabolites, were detected in ether extracts of bile from rat given 2,6-DNT. 4. Potassium 2,4-DNB-G was transformed by the anaerobic incubation of rat intestinal microflora into 2,4-DNB, 4-amino-2-nitrobenzyl alcohol and 2-amino-4-nitrobenzyl alcohol. Potassium 2,6-DNB-G was transformed into 2,6-DNB and 2-amino-6-nitrobenzyl alcohol by the anaerobic incubation. Time-course studies showed that 2,4-DNB, 4-amino-2-nitrobenzyl alcohol, 2-amino-4-nitrobenzyl alcohol and 2,6-DNB, 2-amino-6-nitrobenzyl alcohol peaked at 30, 75, 120 and 10, 50 min respectively. 5. These results, together with previous findings, show that 2,4-dinitrobenzaldehyde and 2,6-dinitrobenzaldehyde, which are potent mutagens, are formed either by the hepatic metabolism of 2,4-DNB and 2,6-DNB formed by the intestinal metabolism of 2,4-DNB-G and 2,6-DNB-G excreted in bile or by the direct hepatic metabolism of 2,4-DNT and 2,6-DNT.

Animals↗
PubMed1996

The problem of relating fetal outcome with breech presentation to mode of delivery.

We retrospectively analyzed 546 consecutive singleton pregnancies with breech presentations that ended at > or = 36 weeks of gestation for the relationship between the intended mode of delivery and fetal outcome. Twelve patients were excluded from the analysis because these infants had major malformations. Of the 534 remaining patients, 124 (23%) were delivered by elective cesarean section. The other 410 women (77%) went into spontaneous labor. Intrapartum emergency cesarean section was required in 112 (27%) of these 410 women; the other 298 (73%) were delivered vaginally. There were 5 poor neonatal outcomes: 3 perinatal deaths and 2 cases of cerebral palsy probably due to intrapartum asphyxia. The risk of poor outcome was thus 1.2% (5/410), in the intended vaginal delivery group vs. no such outcome in the group of 124 patients that had an elective cesarean section. Three of 5 infants with poor outcome were actually born by emergency cesarean section and comparisons of results according to ultimate method of delivery rather than according to intended method of delivery may be misleading and in our case would have been biased against cesarean section.

Asphyxia Neonatorum↗
PubMed1996

The clinical efficacy of gamete intrafallopian transfer by minilaparotomy versus in vitro fertilization and embryo transfer.

OBJECTIVE: To evaluate the clinical performance of gamete intrafallopian transfer (GIFT) and in vitro fertilization and embryo transfer (IVF-ET). METHODS: Infertile women were divided into 2 groups: for GIFT, 239 patients (326 cycles) with at least 1 patent tube; and, for IVF-ET, 125 patients (210 cycles) with bilateral tubal occlusion. A specially designed retractor was developed to replace the gametes into an appropriate section of the Fallopian tube accurately and safely. Several parameters, including the pregnancy and delivery rates of each group, were compared. RESULTS: The success rate per trial in the GIFT group was approximately 1.5 times higher than that in the IVF group (pregnancy rate: 44.2% vs. 31.0%, p < 0.01; delivery rate: 33.4% vs. 22.9%, p < 0.01). The pregnancy and delivery rates of GIFT decreased steadily with the number of trials. These apparent decreases were not observed up to the 3rd trial in IVF-ET cases. CONCLUSIONS: GIFT with a minilaparotomy procedure yielded significantly higher success rates than IVF-ET. Accordingly, GIFT is considered to be the first treatment choice in infertility cases with at least 1 patent Fallopian tube.

Adult↗
PubMed1995

The effect of managed care on the treatment outcome of substance use disorders.

This study examined the effect of managed care and other reimbursement mechanisms on the outcome of substance abuse treatment at a single treatment facility. A retrospective review of 1594 patient records yielded treatment utilization, diagnostic, and demographic data. Recidivism rates for intensive managed care, traditional managed care, private pay, and state-funded groups of patients were compared. Results showed that, contrary to expectations, recidivism rates were not different for managed vs nonmanaged care patients. In addition, recidivist patients had significantly more ICD-9 diagnoses than nonrecidivist patients. A discussion of future research suggests that other outcome measures need to be examined in addition to recidivism rate, such as psychosocial functioning following treatment and indicator(s) of severity of illness, to better determine the effect of managed care and other reimbursement mechanisms on treatment outcome.

Adult↗
PubMed1994

The acceptability of prenatal diagnosis in Japan.

Prenatal diagnosis has been performed more frequently in Japan recently, but is still less popular than in the United States or Europe. Legal arrangements, insufficient economic support, and insufficient medical information provided to future parents may explain this difference. The acceptability of prenatal diagnosis, based on the concept of the cost of side effects and elective abortion, was found to be similar when examined through decision analysis and direct survey. Amniocentesis was considered useful for more than half of couples in Japan when the incidence of chromosomal abnormality is more than 0.5% and proper information about the decision to undergo this examination is provided to the pregnant woman and her family.

Abortion, Eugenic↗
PubMed1994

Enzyme-cytochemistry of human chorion laeve at term: enzyme localization on the chorionic trophoblast.

Is the chorion laeve merely a remnant of the chorion frondosum in placental development? Or is it metabolically active, having something to do with maternofetal interactions? In order to answer these questions at least in part, we determined the ultracytochemical localizations of some important enzymes such as nonspecific phosphatase (alkaline phosphatase), specific phosphatase (Ca(++)-ATPase and 5'-nucleotidase) and adenylate cyclase in the human chorion laeve at term. Strong activities of these enzymes were localized by ultracytochemistry on the plasma membrane of the trophoblast in the chorion laeve. These enzyme activities were confirmed by a series of cytochemical-control experiments, i.e., substrate-free control, heat-stability control, and inhibition control by inhibitors of alkaline phosphatase. These observations indicate that the chorionic trophoblast is probably metabolically active and that it might play an important role in the physiology of the fetal membrane.

5'-Nucleotidase↗
PubMed1994

Enzyme-cytochemistry of human chorion laeve at term: enzyme localization on the chorionic trophoblast.

Is the chorion laeve merely a remnant of the chorion frondosum in placental development? Or is it metabolically active, having something to do with maternofetal interactions? In order to answer these questions at least in part, we determined the ultracytochemical localizations of some important enzymes such as nonspecific phosphatase (alkaline phosphatase), specific phosphatase (Ca(++)-ATPase and 5'-nucleotidase) and adenylate cyclase in the human chorion laeve at term. Strong activities of these enzymes were localized by ultracytochemistry on the plasma membrane of the trophoblast in the chorion laeve. These enzyme activities were confirmed by a series of cytochemical-control experiments, i.e., substrate-free control, heat-stability control, and inhibition control by inhibitors of alkaline phosphatase. These observations indicate that the chorionic trophoblast is probably metabolically active and that it might play an important role in the physiology of the fetal membrane.

Alkaline Phosphatase↗
PubMed1993

Studies on the permeability and enzyme-cytochemistry of the mouse hemotrichorial placenta.

The permeability of higher molecular weight substances was investigated in mouse chorioallantoic labyrinthine hemotrichorial placenta, using horseradish peroxidase as a tracer. At the same time, ultrastructural localizations of some important enzymes, such as alkaline phosphatase (ALP), acid phosphatase (ACP), Ca(++)-ATPase and guanylate cyclase were elucidated in this organ by means of the enzyme-cytochemical technique. Peroxidase easily entered the space between layers I and II, and no penetration of this tracer beyond layer II was observed. The reaction products for ALP activity were found mainly on the maternal side of the plasma membrane of the layer II trophoblast. ACP activity was confined to the lysosomes of this layer II cell. In short, peroxidase stopped at the cell surface of the layer II trophoblast, and both ALP and ACP coexisted in this layer II cell. These observations strongly suggest that the layer II trophoblast, especially the surface plasma membrane of this cell, may have an important role in regulating the materno-fetal transfer of substances in mouse chorioallantoic placenta.

Acid Phosphatase↗
PubMed1993

Intestinal transformation of 2,6-dinitrotoluene in male Wistar rats.

1. Metabolites formed by anaerobic incubation of 2,6-dinitrotoluene (2,6-DNT) with intestinal microflora of male Wistar rats were examined. Intestinal transformation of 2,4-dinitrotoluene (2,4-DNT) was also studied to determine whether azoxy compounds are produced in the anaerobic incubation. 2. 2,6-DNT was transformed by the intestinal microflora into 2-nitroso-, 2-hydroxylamino- and 2-amino-6-nitrotoluene, and 2,6-diaminotoluene. A time course study showed that 2-nitroso-, 2-hydroxylamino-, and 2-amino-6-nitrotoluene reached peaks at 2, 5 and 6 h of the anaerobic incubation; 2,6-diaminotoluene appeared at 12 h of the incubation. The formation of 2,6-diaminotoluene from 2-amino-6-nitrotoluene in the incubation was confirmed. 3. Two nitroazoxy compounds, namely, 2,2'-dimethyl-5,5'-dinitroazoxybenzene and 4,4'-dimethyl-3,3'-dinitroazoxybenzene, in addition to known metabolites (nitrosonitrotoluenes, hydroxylaminonitrotoluenes, aminonitrotoluenes and diaminotoluene), were detected in the incubation of 2,4-DNT with intestinal microflora. The formation of the two nitroazoxy compounds (2% dose in 24 h) was non-enzymic and merely involved mixing 2-hydroxylamino-4-nitrotoluene with 2-nitroso-4-nitrotoluene or 4-hydroxylamino-2-nitrotoluene with 4-nitroso-2-nitrotoluene in methanol, respectively.

Animals↗
PubMed1992

Bacterial metabolism of 2,6-dinitrotoluene with Salmonella typhimurium and mutagenicity of the metabolites of 2,6-dinitrotoluene and related compounds.

1. Metabolites produced by the incubation of 2,6-dinitrotoluene (2,6-DNT) with Salmonella typhimurium strains TA 98, TA 98/1,8-DNP6 and TA 98NR were examined. Mutagenicities of bacterial products and related compounds were also examined in the Ames assay using TA 98 and TA 100. 2. 2,6-DNT was converted to 2-nitroso-6-nitrotoluene, 2-hydroxylamino-6-nitrotoluene and 2-amino-6-nitrotoluene, with concurrent spontaneous formation of 2,2'-dimethyl-3,3'-dinitroazoxybenzene, in the incubation with TA 98 and TA 98/1,8-DNP6. Capacity of TA 98NR to reduce 2,6-DNT was much lower than that of TA 98 and TA 98/1,8-DNP6. 3. Bacterial products, including 2,2'-dimethyl-3,3'-dinitroazoxybenzene, showed no mutagenic activity in the Ames assay. 4. Results indicate that the lack of mutagenic activity of 2,6-DNT is not due to low reductive metabolism of 2,6-DNT by bacteria, but due to the lack of mutagenic activity of the bacterial reductive products of 2,6-DNT.

Animals↗