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Biomedical subjects

T Araki

Publications and source records attributed to T Araki.

At least 163 records · Page 9Linked to original sources

Cloning, sequencing, and expression in Escherichia coli of the new gene encoding beta-1,3-xylanase from a marine bacterium, Vibrio sp. strain XY-214.

The Vibrio sp. strain XY-214 beta-1,3-xylanase gene cloned in Escherichia coli DH5alpha consisted of an open reading frame of 1, 383 nucleotides encoding a protein of 460 amino acids with a molecular mass of 51,323 Da and had a signal peptide of 22 amino acids. The transformant enzyme hydrolyzed beta-1,3-xylan to produce several xylooligosaccharides.

Cloning, Molecular↗

Islet cell tumor of the pancreas: biphasic CT versus MR imaging in tumor detection.

PURPOSE: To compare the effectiveness of biphasic computed tomography (CT) and magnetic resonance (MR) imaging in the detection of pancreatic islet cell tumors. MATERIALS AND METHODS: Retrospective quantitative, qualitative, and receiver operating characteristic analyses of biphasic CT and MR imaging were performed in 19 patients with 26 histopathologically proved islet cell tumors. Delayed arterial dominant-phase (AP) and portal venous-phase (PVP) biphasic CT was performed after the administration of contrast material. MR imaging included T1-weighted spin-echo (SE) and T2-weighted SE or fast SE imaging, fat-saturated T1-weighted SE imaging, dynamic contrast material-enhanced T1-weighted gradient-echo imaging, and delayed enhanced T1-weighted SE imaging with or without fat saturation. RESULTS: PVP CT and delayed enhanced T1-weighted MR imaging had the highest A(z) values (0.98 and 0.97, respectively; P <.05). Delayed enhanced T1-weighted MR imaging had the highest relative sensitivity (14-15 [74%-79%] of 19 lesions), followed by PVP CT (18-19 [69%-73%] of 26 lesions), AP CT (17-19 [65%-73%] of 26 lesions), fat-saturated T1-weighted MR imaging (eight to 10 [57%-71%] of 14 lesions), T2-weighted (16-17 [62%-65%] of 26 lesions), T1-weighted (15-18 [58%-69%] of 26 lesions) MR imaging, and dynamic MR imaging (nine [56%] of 16 lesions). CONCLUSION: Biphasic (especially PVP) CT and MR imaging have similar effectiveness in the detection of islet cell tumors if fat-saturated T1-weighted and delayed enhanced T1-weighted MR imaging are included.

Adenoma, Islet Cell↗

Clinical trial of induction of labor versus expectant management in twin pregnancy.

OBJECTIVE: The appropriate date of delivery in twin pregnancies is supposed to be earlier than that in singleton pregnancy. The aim of this study was to compare two strategies for managing twin pregnancies (i.e., immediate induction and expectant management). METHODS: Seventeen patients underwent immediately induced labor by administration of oral prostaglandin E(2) at 37 weeks, while 19 patients underwent expectant management. RESULTS: The average gestational age at delivery in the induction group was 37.5 +/- 0.4 weeks, significantly earlier than that in the expectant management group (39.0 +/- 1.1 weeks). However, there were no significant differences in the average birth weight between the two groups (2, 700 +/- 330 g in the induction group vs. 2,672 +/- 392 g in the expectant management group). The cesarean delivery rate in the induction group was 18%, not significantly different from that in the expectant management group (32%). The most common indication for cesarean section in the expectant management group was maternal infection, while there was no maternal infection in the induction group (p = 0.08). CONCLUSION: It may be acceptable do intervene in twin pregnancies earlier than in singleton pregnancies during term.

Adult↗

Changes in plasma adenosine concentrations during normal pregnancy.

The aim of this study was to measure changes in plasma adenosine concentration [ADO] during a normal pregnancy and to evaluate the possible role of platelets and red blood cells (RBC) as causes of changes in plasma [ADO]. We measured the plasma [ADO] in normal pregnant women (n = 11) during the first, second and third trimesters. The mean plasma [ADO] in the third trimester was 0.41 +/- 0.08 microM (means +/- SEM), significantly higher than in the first and second trimesters (p < 0.05). In pregnant women, platelet and RBC counts, hematocrit and hemoglobin concentration decreased slightly throughout the pregnancy. The elevation in the plasma [ADO] correlated inversely with the platelet count (r = -0.43, p < 0.05). These results suggest that an increase in the plasma [ADO] in the third trimester may be attributed to the enhanced adenosine release from activated platelets.

Adenosine↗

Prognostic significance of blood pressure and heart rate variabilities: the Ohasama study.

To investigate the association between cardiovascular mortality and short-term variabilities in blood pressure and heart rate, we performed a long-term prospective study of ambulatory blood pressure monitoring in Ohasama, Japan, starting in 1987. We obtained ambulatory blood pressure and heart rate in 1542 subjects >/=40 years of age. Blood pressure and heart rate variabilities were estimated as a standard deviation measured every 30 minutes by ambulatory monitoring. There were 67 cardiovascular deaths during the follow-up period (mean=8.5 years). The Cox proportional hazards model, adjusted for possible confounding factors, demonstrated a significant increase in cardiovascular mortality, with an increase in daytime systolic ambulatory blood pressure variability. A similar trend was observed in daytime diastolic and nighttime ambulatory blood pressures. Cardiovascular mortality rate increased linearly, with a decrease in daytime heart rate variability. Subjects in whom the daytime systolic ambulatory blood pressure variability was larger than third quintile and the daytime heart rate variability was lower than the mean-SD were at extremely high risk of cardiovascular mortality. The blood pressure and heart rate variabilities obtained every 30 minutes by ambulatory blood pressure monitoring were independent predictors for cardiovascular mortality in the general population.

Aged↗

Effect of alpha-phenyl-N-tert-butyl nitrone (PBN) on fetal cerebral energy metabolism during intrauterine ischemia and reperfusion in rats.

The objective of the present study was to explore whether a free radical spin trap agent, alpha-phenyl-N-tert-butyl nitrone (PBN), influences bioenergetic failure induced in the 20-day-old fetal brain by 30 min of intrauterine ischemia in Wistar rats. Fetal brains were frozen in situ at the end of ischemia and after 1, 2, and 4 h of recirculation for analysis of ATP, ADP, AMP, and lactate. PBN or vehicle was given 1 h after recirculation. Tissue oxygen tension was evaluated in placental and fetal cerebral tissues throughout the whole periods of 30 min of ischemia and 4 h of recirculation. Ischemia was associated with a decrease in ATP concentration and an increase in lactate concentration (p < 0.001). Recirculation (1 and 2 h) led to a recovery of ATP concentration, but continued reflow (4 h) was associated with a secondary deterioration of high-energy phosphates (p < 0.01). Lactate concentration increased during this recovery period. This deterioration was prevented by PBN (p < 0.05). After 30 min of ischemia, tissue oxygen tension in placenta and fetal brain decreased to about 30% and 50% of control, respectively. However, recirculation brought about a recovery of oxygen delivery. The results indicate that although during the early time period after ischemia fetal cerebral energy metabolism is maintained by an acceleration of the anaerobic glycolytic rate, secondary deterioration of cellular bioenergetic state develops in the immature fetal brain. This deterioration may be due to mitochondrial dysfunction, which may be induced by oxygen-derived free radicals, and not by compromised microcirculation.

Animals↗

Femoral bone density and changes therein associated with differing histories of pregnancy and lactation in aged rats.

OBJECTIVE: To examine the effect of prior pregnancy and lactation on bone density in aged rats. MATERIALS AND METHODS: 2 month-old female Fischer-344 rats were divided into 4 groups: 1)13 rats were allowed to get pregnant and to nurse their offspring for two or three cycles; 2)14 rats were allowed to get pregnant two or three times and were immediately separated from their young after each delivery prior to lactation; 3)10 rats were not allowed to become pregnant; and 4)7 rats were sacrificed at the beginning of the experiment. All rats were fed ad libitum. After the rats had completed two or three pregnancies with or without subsequent lactation, all were fed a restricted diet until they were 25 months old (aged rats). Then they were sacrificed and both femurs were removed from each rat. One bone was used for analysis of mineral content and the other bone was used for photodensitometry of the diaphysis. RESULTS: 31 rats (83.8% ) survived until they were sacrificed. The femurs of the aged rats showed increased ash weight compared to those of 2 month-old rats. Aged rats with prior pregnancies with or without subsequent lactation had higher femoral ash weight than those without prior pregnancies. There were no differences among aged rats in regard to marrow diameter, bone diameter, cortical width or bone density of the diaphysis in femur by photodensitometry. CONCLUSION: In aged rats, past pregnancies but not lactation were related to increases in bone density of the femur.

Aging↗

Primary aldosteronism in pregnancy.

Aldosteronism is a rare complication of pregnancy. We report a case of a 26-year-old woman who became pregnant soon after a diagnosis of primary aldosteronism due to left adrenal adenoma was made. Only oral potassium supplementation was required in addition to routine prenatal care until 36 weeks' gestation. Subsequently, antihypertensive medication was needed to control elevated blood pressure. A healthy male infant was delivered by cesarean section because of abruptio placentae. The postoperative course was uneventful. Left adrenalectomy was conducted eight months after delivery under laparoscopic visualization. In this case report, we discuss management of aldosteronism in pregnancy and review the literature.

Abruptio Placentae↗

Prediction of uterine dehiscence by measuring lower uterine segment thickness prior to the onset of labor: evaluation by transvaginal ultrasonography.

OBJECTIVE: Lower uterine segment thickness was measured by transvaginal ultrasound examination and its correlations with the occurrence of uterine dehiscence and rupture was examined. METHODS: The thickness of the muscular layer of the lower uterine segment was measured in 186 term gravidas with previous uterine scars and its correlation with uterine dehiscence/rupture was investigated. RESULTS: Uterine dehiscence was found in 9 cases or 4.7%. There were no cases of the uterine rupture. The thickness of the lower uterine segment among the gravidas with dehiscence was significantly less in than those without dehiscence (p< 0.01). The cut-off value for the thickness of the lower uterine segment was 1.6 mm as calculated by the receiver operating characteristic curve. The sensitivity was 77.8%; specificity 88.6%; positive predictive value 25.9%; negative predictive value 98.7%. CONCLUSION: Measurement of the lower uterine segment is useful in predicting the absence of dehiscence among gravidas with previous cesarean section. If the thickness of the lower uterine segment is more than 1.6 mm, the possibility of dehiscence during the subsequent trials of labor is very small.

Adult↗

Changes in maternal lipid peroxidation levels and antioxidant enzymatic activities before and after delivery.

OBJECTIVE: Our goal was to characterize the changes in maternal lipid peroxidation levels and antioxidant enzymatic activities before and after delivery. METHODS: Predelivery and 1, 24, and 48 hours post-partum plasma concentrations of malondialdehyde, erythrocyte enzyme superoxide dismutase, glutathione peroxidase and catalase were measured in uncomplicated pregnancies. RESULTS: Malondialdehyde levels increased slightly from predelivery to 24 hours post-partum and then decreased significantly at 48 hours post-partum. At one hour post-partum superoxide dismutase and catalase levels increased significantly to about 125% and 170% of predelivery levels, respectively. Thereafter, these values decreased significantly from one hour to 48 hours post-partum. The relative changes in superoxide dismutase and catalase levels at one hour post-partum compared to predelivery values correlated significantly with the duration of labor. CONCLUSION: The results suggest that the uncontrolled lipid peroxidation caused by reactive oxygen species, which are produced in consequence of tissue reoxygenation, may occur during labor and that prolonged labor, may cause maternal oxidative stress.

Adult↗

Correlations of calcium accumulations in arteries, veins, cartilages, ligaments, and bones in single humans.

To show the relationships of calcium accumulation in the thoracic aorta to the other tissues, calcium contents were determined with a microwave-induced plasma-atomic emission spectrometer on arteries, veins, cartilages, ligaments, and bones. These tissues were resected from 18 individuals, consisting of 11 men and 7 women who died in the age range 59-91 yr. As thoracic and abdominal aortas are routinely used for radiographic examination of arterial calcification, they appear to be standard tissues of the calcium accumulation. The calcium accumulations were determined in the femoral artery, the superior and inferior venae cavae, the internal jugular vein, cartilages of the articular disk of the temporomandibular joint and the intervertebral disk, both the ligaments of the anterior cruciate ligament and the ligamentum capitis femoris, and the calcaneus, in contrast with the thoracic aorta. As calcium increased in the thoracic aorta, it increased in the femoral artery, the articular disk of the temporomandibular joint, the intervertebral disk, both ligaments of the anterior cruciate ligament, and the ligamentum capitis femoris, but it did not increase in veins, such as the superior and inferior venae cavae and the internal jugular vein. In contrast, it decreased in the calcaneus.

Aged↗

Changes in fetal plasma adenosine and xanthine concentrations during fetal asphyxia with maternal oxygen administration in ewes.

In this study, we measured fetal plasma adenosine and xanthine concentrations during and after severe asphyxia, and investigated the key issues related to oxygen therapy. Asphyxia was induced by occluding the umbilical cord for 5 minutes in 6 fetal sheep with and without the administration of oxygen to the ewe. Plasma adenosine concentration increased significantly during cord occlusion in the all fetuses, and the differences between the values in the fetuses with and without maternal oxygen administration was not significant. By 30 minutes after cord release, plasma adenosine concentration in all fetuses had returned to levels similar to those at the start of the experiment. Plasma xanthine concentration also increased during cord occlusion in all fetuses. However, 30 minutes after cord release, plasma xanthine concentration had decreased significantly in fetuses without additional oxygen, while it did not change significantly in fetuses with maternal oxygen administration. Thus, we speculated that maternal oxygen administration before fetal asphyxia may not contribute to additional ATP stores in fetal organs and may produce oxygen free radicals following asphyxia.

Adenosine↗

Glycolaldehyde, a reactive intermediate for advanced glycation end products, plays an important role in the generation of an active ligand for the macrophage scavenger receptor.

Long-term incubation of proteins with glucose leads to the formation of advanced glycation end products (AGEs) that are recognized by AGE receptors. Glyoxal, glycolaldehyde (GA), and methylglyoxal are potential intermediates for the formation of AGE structures such as Nomega-(carboxymethyl)lysine (CML). We evaluated the contribution of these aldehydes to the formation of AGE structure(s), particularly the structure important for the receptor-mediated endocytic uptake of AGE proteins by macrophages. GA-modified bovine serum albumin (BSA), methylglyoxal-modified BSA (MG-BSA), and glyoxal-modified BSA (GO-BSA) were prepared, and their physicochemical, immunological, and biologic properties were compared with those of glucose-derived AGE-BSA. CML contents were high in GO-BSA and low in GA-modified BSA (GA-BSA) but did not exist in MG-BSA. The fluorescence patterns of GA-BSA and MG-BSA were similar to those of glucose-derived AGE-BSA but were weak in GO-BSA. Immunochemically, the antibody against non-CML structures of glucose-derived AGE-BSA reacted strongly with GA-BSA and weakly with GO-BSA but did not react with MG-BSA. The negative charge of these ligands increased to a similar extent. However, GA-BSA, but not MG-BSA or GO-BSA, underwent receptor-mediated endocytosis by the macrophage-derived cell line RAW 264.7, which was effectively inhibited by glucose-derived AGE-BSA, acetylated LDL, and oxidized LDL, which are well-known ligands for the macrophage type I and type II class A scavenger receptors (MSR-A). The endocytic uptake of GA-BSA by mouse peritoneal macrophages was also significant, but that by peritoneal macrophages from MSR-A-deficient mice was markedly reduced. Our results suggest that GA serves as an important intermediate for the generation of AGE structure(s) responsible for recognition by MSR-A.

Animals↗

Magnetic resonance appearance of multiple intracranial epidermoid cysts: intrathecal seeding of the cysts? Case report.

A 44-year-old man presented to the hospital with multiple intracranial epidermoid cysts. The clinical manifestations of his disease included chronic headaches and one seizurelike episode. Findings determined by magnetic resonance (MR) imaging, surgery, and histological analysis indicated intrathecal and intraventricular seeding of the cysts. Spontaneous (nontraumatic) seeding of multiple daughter cysts from intracranial epidermoid cysts is still very rare and their multiple appearances on MR imaging should be distinguished from the simple scattering of oily contents due to cyst rupture.

Adult↗

Dynamic contrast-enhanced MR angiography and MR imaging of the carotid artery: high-resolution sequences in different acquisition planes.

BACKGROUND AND PURPOSE: First-pass contrast-enhanced MR angiography has become the technique of choice for studying the carotid bifurcation, but this method has some limitations. We evaluated the clinical utility of performing 3D contrast-enhanced MR angiography in the axial plane immediately after performing angiography in the coronal plane. METHODS: Cervical carotid arteries of 80 consecutive patients were studied on a 1.5-T MR imager with phased-array coils. Coronal 3D MR angiography was performed after administering a bolus injection of contrast material (20 mL) with automatic triggering. This was immediately followed by an axial acquisition. We measured carotid diameters on the contrast-enhanced MR angiograms as well as on intra-arterial digital subtraction angiograms according to established criteria. We also evaluated original source MR angiograms. RESULTS: Angiograms obtained in the axial plane correlated better with the intra-arterial digital subtraction angiograms than did the coronal angiograms. When first-pass contrast-enhanced MR angiography was incomplete because of a failure of triggering, the second-phase acquisition provided sufficient image quality. Original source images suffered from ring artifacts, low axial resolution, and a low level of soft-tissue visualization. Axial-based source images showed flow-independent contrast filling to the patent lumen with sufficient visualization of plaque morphology, thickened arterial wall, and surrounding disease processes, such as tumors. CONCLUSION: With the addition of a 1-minute second-phase 3D acquisition in a different plane immediately after first-pass contrast-enhanced MR angiography, one can obtain a more accurate depiction of the carotid bifurcation, insurance against failure of triggering, and diagnostic source images.

Adolescent↗