Biomedical subjects

K Togashi

Publications and source records attributed to K Togashi.

At least 37 records · Page 2Linked to original sources

PubMed2002

Oviposition deterrence associated with larval frass of the Japanese pine sawyer, Monochamus alternatus (Coleoptera: Cerambycidae).

To determine the effect of larval frass of Monochamus alternatus on oviposition preference of the female adults, three tests were performed in the laboratory. Individual females were provided with a frass-coated, Pinus densiflora bolt and an untreated bolt simultaneously and were allowed to oviposit for 24 h. They deposited a significantly smaller number of eggs on frass-coated bolts. The females supplied with frass-coated bolts deposited no eggs on them, indicating that the larval frass deterred the females from oviposition. When individual females were provided simultaneously with a pine bolt applied with a methanol extract of larval frass and another bolt applied with methanol alone, they deposited a significantly smaller number of eggs on frass extract-applied bolts for 24 h. These results suggest the presence of a putative oviposition deterrent in larval frass of M. alternatus. Each test was replicated 19-20 times using different females.

Journal Article↗

PubMed2002

Is adiposity at normal body weight relevant for cardiovascular disease risk?

OBJECTIVE: To examine the relation between adiposity and risk factors for cardiovascular disease (CVD) in normal weight (NW) individuals. METHODS: Cross-sectional study using the sample of white people, aged from 17 to 60 y from the Québec Family Study and the Heritage Family Study. NW subjects with a body mass index (BMI) between 18.5 and 25 kg/m(2) (181 males and 265 females) and overweight (OW) subjects with a BMI between 25 and 30 kg/m(2) (133 males and 114 females) were retained for this study. NW subjects were divided into quintiles of each adiposity variable, then the quintiles and the OW group were evaluated for the presence of CVD risk factors. Using logistic regression analysis, the odds ratio (OR) for the prevalence of risk factors for each quintile of each adiposity variable and the OW group was estimated relative to the first quintile in NW subjects. Mean values of adiposity variables were compared between the subjects with and without risk factors. In these analyses, age and study cohort effects were taken into account. MEASUREMENTS: Percentage body fat (%fat) and fat mass (FM) measured by underwater weighing were available as adiposity variables. Risk factors included systolic and diastolic blood pressure, LDL and HDL cholesterol, triglycerides and fasting glucose. RESULTS: Wide ranges of values were observed for adiposity variables. HDL cholesterol, triglycerides and fasting glucose in NW males and HDL cholesterol in NW females were significantly correlated with all adiposity variables. For males, higher quintiles of adiposity variables in the NW group and the OW group tended to have higher ORs compared to the first quintiles for the risk factor variables. The fifth quintiles of all adiposity variables had the highest ORs (3.15 for %fat and 3.77 for FM) and they were significantly different from the first quintiles. OW males had ORs similar to those of the fifth quintiles for the risk factor variables. On the other hand, for females, the relatively linear associations were less clear in the NW group. In NW males, the subjects with at least one risk factor had significantly higher %fat and FM than the subjects without risk factors. In NW females, no significant difference was observed for these adiposity variables between the subjects with and without risk factors. CONCLUSION: NW males with elevated adiposity had higher prevalence of risk factors than NW males with less adiposity and the prevalence in the former was rather similar to that seen in OW males. On the other hand, measures of adiposity added little additional information to the BMI classification of NW on CVD risk factors in females.

Adipose Tissue↗

PubMed2002

A 12-year follow-up study of treated obese children in Japan.

OBJECTIVE: To assess tracking for body weight from childhood to adulthood in obese Japanese children who were treated for obesity, investigate the relation between the changes in body weight status and morbidity, and identify correlates of the changes in body weight status. STUDY DESIGN: Twelve-year retrospective cohort study. SUBJECTS: A sample of 276 subjects (age 23.9+/-4.1, 176 males and 100 females) who responded to a questionnaire mailed in 1998 to 1047 children (age 10.6+/-2.2) treated for obesity at Mie National Hospital in Japan between 1976 and 1992. MEASUREMENTS: Based on height and weight from medical records during childhood, the relative weight (RW; weight expressed as a percentage of the standard body weight for age, height, and sex) was calculated. Degrees of childhood obesity were based on RW: slight obesity (120% < or = RW<130%; n=17), moderate obesity (130% < or = RW <150%; n=131), and severe obesity (RW > or = 150%; n=128). Adult body mass index (BMI), which was obtained from the mailed questionnaires, was classified as normal, overweight and obese according to the WHO/NIH criteria. Body weight tracking by degree of obesity was evaluated. Subjects with severe obesity during childhood (n=128) were examined for their weight status in adulthood, prevalence of chronic diseases in adulthood, and factors such as parental obesity, dietary and exercise habits and obesity treatment during childhood. RESULTS: Childhood obesity tracked into adulthood obesity or overweight in 54.7% of all cases. Severely obese children (36.7%) were more likely to be obese as an adult than moderately obese children (16.8%). The prevalence of adult obesity tended to be greater in boys with moderate childhood obesity than in girls (29.7% in boys vs 14.9% in girls, P=0.058). Among the severely obese children who became normal-weight adults, the prevalence of chronic diseases was about one-fifth of those who remained obese in adulthood (P=0.041). Four factors were associated with changes in body weight status: maternal BMI at entry (P=0.044), the changes in dietary and exercise habits after treatment (P=0.014, P=0.030, respectively), and satisfaction with obesity treatment in childhood (P=0.035). CONCLUSIONS: Severely obese children have a higher risk of becoming obese adults even when they received obesity treatment in childhood. The risk of adulthood obesity was twice as high in moderately obese boys than in girls. On the other hand, many cases of childhood obesity can be corrected with obesity treatment, which in turn can decrease the risk for adult chronic diseases.

Adolescent↗

PubMed2002

[Surgery for synchronous primary lung cancers and intrapulmonary metastases].

Between 1988 and 2000, 1,040 patients with primary lung cancer underwent pulmonary resection at Nagaoka Red Cross Hospital. Thirty-one (2.9%) patients had synchronous primary lung cancer (group A) and 78 patients (7.5%) had intrapulmonary metastases (group B). The 5-year and 10-year survival rate for group A was 64% and 56% respectively and for group B 37% and 32% respectively. The patients in group A showed a better survival rate in the different lobes (80% at 5 years) than in the same lobe (55%), while those in group B gave reverse results (31% and 42%). In group A, the patients had a better survival rate in the different histology (73% at 5 years) than in the same histology (45%). The 5-year survival was 65% for 20 patients with stage I disease, 75% for 4 patients with stage II disease, 43% for 75 patients with stage III and 25% for 10 patients with stage IV. These data suggest that synchronous primary lung cancer had a better prognosis than primary lung cancer with satellite nodules, but the histological discrimination between multiple lung cancers and intrapulmonary metastases was uncertain.

Adult↗

PubMed2002

[Surgery for intrathoracic recurrence and second primary tumors in resected lung cancer].

From 1986 to 2000, 42 patients (3.7%) underwent resection for intrathoracic recurrence or second primary lung cancer. Survival in 27 patients with recurrent diseases was 60% at 5 years and 35% at 10 years compared with 65% at 5 and 10 years for 15 patients with metachronous lung cancers morphologically. Ten patients had the second operation less than 2 years since the first operation, 19 patients between 2 and 5 years, and 13 patients more than 5 years, while these 5-year survivals were 72%, 53%, 67% respectively. At the first operation lobectomy was performed in 39 patients (93%), wedge resection or segmentectomy in 3. The reoperation was 14 lobectomy or completion pneumonectomy, 24 wedge or segmentectomy (57%), and 4 other procedures, while these 5-year survivals were 35%, 73%, and 100% respectively. The 5-year survival was 78% for 27 patients with stage I disease and 26% for 10 patients with stage III disease at the first operation, compared with 55% for 30 patients with stage I and 53% for 9 patients with stage III at the reoperation. These data suggest that limited resection is recommended for intrathoracic recurrent diseases and metachronous multiple lung cancers whenever possible.

Adult↗

PubMed2001

Exhaled nitric oxide decreases during exercise-induced bronchoconstriction in children with asthma.

Nitric oxide (NO) produced in the airways can be either detrimental or protective to the host. To investigate the role of NO in the pathogenesis of exercise-induced bronchoconstriction (EIB), we measured exhaled NO (ENO) after exercise challenge in 39 asthmatic and six normal children. FEV(1) and ENO were measured before and at 0, 5, 10, and 15 min after exercise performed on a treadmill for 6 min. EIB was defined as a decrease in FEV(1) of more than 15% after the exercise. Normal children (control group) did not have EIB. Twenty-one patients with asthma had EIB (EIB group) whereas the remaining 18 patients did not (non-EIB group). The baseline ENO value was significantly higher in the asthmatic children than in the normal children, and there was a positive correlation between the maximal percent decrease in FEV(1) and the baseline ENO value (r = 0.501, p = 0.012). At the end of the exercise, ENO had decreased in all the subjects. In the non-EIB and control groups, ENO rebounded to above the baseline at 5 min after the exercise and thereafter. In contrast, ENO remained at a decreased level in the EIB group. The change in ENO did not correlate with the change in minute ventilation, and beta-agonist inhalation at the peak of EIB that accelerated the recovery of FEV(1) did not affect the depressed level of ENO, demonstrating that the reduction of ENO is not a simple consequence of increased ventilation nor airway obstruction. Among the EIB group, steroid-treated patients showed sooner recovery in ENO after the exercise than steroid-naive patients. Our study suggests that NO production in response to exercise may be impaired in patients with EIB, and that ENO represents not only airway inflammation but also a protective function of NO in EIB.

Administration, Inhalation↗

PubMed2001

Regulation of catalytic activity of a multifunctional polyketide biosynthetic enzyme, 6-hydroxymellein synthase, by interaction between NADPH and phenylglyoxal-sensitive amino acid residue at the reaction center.

Treatment of 6-hydroxymellein synthase, a multifunctional polyketide biosynthetic enzyme in carrot cells, with phenylglyoxal yielded a chemically modified protein in which approximately two moles of the reagent were covalently attached to each subunit of the enzyme. Only NADH- but not NADPH-associated form of native 6-hydroxymellein synthase was inhibited by cerulenin; however, the NADPH-synthase complex lost the insensitivity by the chemical modification of the enzyme protein with phenylglyoxal. Appreciable differences in K(m) values observed between the NADPH- and NADH-associated enzymes were greatly reduced by the treatment with phenylglyoxal. Although the catalytic activity of the NADPH-associated synthase was enhanced by the addition of free CoA, the compound exhibited a significant inhibitory activity to the phenylglyoxal-modified enzyme. A marked deuterium isotope effect in the catalytic reaction of the native synthase-NADPH complex was appreciably decreased in the chemically modified enzyme. These results strongly suggest that an electrostatic interaction between the phosphate group attached to the 2'-position of adenosyl moiety of NADPH and the phenylglyoxal-sensitive amino acid residue, probably arginine, at the reaction center of 6-hydroxymellein synthase regulates several biochemical properties of this multifunctional enzyme.

Acyltransferases↗

PubMed2001

Dynamic micro-magnetic resonance imaging of liver micrometastasis in mice with a novel liver macromolecular magnetic resonance contrast agent DAB-Am64-(1B4M-Gd)(64).

DAB-Am64-(1B4M-Gd)(64) is a newly synthesized macromolecular liver magnetic resonance imaging (MRI) contrast agent with a polypropylenimine diaminobutane (DAB) dendrimer conjugated with a bifunctional diethylenetriaminepentaacetic acid (DTPA) derivative for complexing Gd(III) atoms. The characteristics of DAB-Am64-(1B4M-Gd)(64), which quickly accumulated in the liver, have been reported recently. In the present study, the dynamic micro-MRI with DAB-Am64-(1B4M-Gd)(64) was obtained in the mouse liver metastasis model using colon carcinoma cells to evaluate the ability to visualize the micrometastatic tumors compared with that using Gd-DTPA. The dynamic micro-MRI with DAB-Am64-(1B4M-Gd)(64) was able to homogeneously enhance the normal liver parenchyma and visualize micrometastatic tumors of 0.3-mm diameter in the liver of the mice with better contrast than that with Gd-DTPA. In conclusion, DAB-Am64-(1B4M-Gd)(64) is a new liver MRI contrast agent potentially useful for diagnosis of micrometastasis in the liver.

Animals↗

PubMed2001

3D-micro-MR angiography of mice using macromolecular MR contrast agents with polyamidoamine dendrimer core with reference to their pharmacokinetic properties.

Four novel macromolecular MRI contrast agents, all of which had the same chemical composition but different molecular weights, were prepared using generation-3, -4, -5, and -6 polyamidoamine (PAMAM) dendrimers conjugated with a bifunctional diethylenetriaminepentaacetic acid derivative to change the blood retention, tissue perfusion, and excretion. Size-dependent changes in the pharmacokinetics were observed in the biodistribution study. (153)Gd-labeled generation-6 PAMAM-conjugates remained in the blood significantly longer than all of the other preparations (P < 0.001). The increase in blood-to-organ ratio of the preparations was found to correlate with increasing molecular size (P < 0.001). Additionally, 3D-micro MR images and angiography of mice of high quality and detail were obtained using PAMAM-(1B4M-Gd)x as a macro-molecular MRI contrast agent with a 1.5-T clinical MRI instrument. Numerous fine vessels of approximately 200 microm diameter were visualized on subtracted 3D-MR angiographms with G6D-(1B4M-Gd)(192). The quality of the images was sufficient to estimate the microvasculature of cancerous tissue for anti-angiogenesis therapy and to investigate knockout mice. Magn Reson Med 45:454-460, 2001.

Animals↗

PubMed2001

Micro-MR angiography of normal and intratumoral vessels in mice using dedicated intravascular MR contrast agents with high generation of polyamidoamine dendrimer core: reference to pharmacokinetic properties of dendrimer-based MR contrast agents.

Pharmacokinetic characteristics of intravascular macromolecular magnetic resonance imaging (MRI) contrast agents with polyamidoamine dendrimer cores smaller than generation-7 were previously studied in the literature. To evaluate the effects of greater hepatic uptake on the pharmacokinetics of the larger generation dendrimers, the MRI contrast agents GxD-(1B4M-Gd)(2(x+2)) were synthesized with generation-7, -8, and -9 polyamidoamine dendrimers and 2-(p-isothiocyanatobenzyl)-6-methyl-diethylenetriaminepentaacetic acid (1B4M). Their pharmacokinetic characteristics in mice were compared with that of G6D-(1B4M-Gd)(256). In biodistribution and dynamic micro-MRI studies, significantly less renal accumulation of G7D-(1B4M-Gd)(512), G8D-(1B4M-Gd)(1024), and G9D-(1B4M-Gd)(2048) was shown compared to G6D-(1B4M-Gd)(256) (P < 0.01). There was a significantly greater accumulation of G8D-(1B4M-Gd)(1024) and G9D-(1B4M-Gd)(2048) in the liver compared to G6D-(1B4M-Gd)(256) and G7D-(1B4M-Gd)(512) (P < 0.01). The highest blood retention of all dendrimer-based MRI contrast agents was exhibited by G7D-(1B4M-Gd)(512) (P < 0.01). The normal and intratumoral fine vessels of approximately 100 microm diameter were visualized in normal or tumor-bearing mice by high resolution three-dimensional-micro-MR angiographs with G7D-(1B4M-Gd)(512) and G8D-(1B4M-Gd)(1024) with good vessel-to-soft tissue contrast. In summary, increased accumulation in the liver with concomitant decreased uptake in the kidney was caused by increased molecular sizes of the dendrimer-based MRI contrast agents.

Analysis of Variance↗

PubMed2001

Anatomy and physiology of the female pelvis: MR imaging revisited.

This article reviews the normal anatomy of the female pelvis and focuses on uterine physiology, presenting the kinematics of the uterus that can be identified on ultra-fast MR imaging. It also discusses the many facets of the junctional zone on MR imaging. Ultra-fast MR imaging seems to be a powerful tool for evaluating normal anatomy, physiology, and pathology of the uterus. J. Magn. Reson. Imaging 2001;13:842-849.

Female↗

PubMed2001

Novel intravascular macromolecular MRI contrast agent with generation-4 polyamidoamine dendrimer core: accelerated renal excretion with coinjection of lysine.

One of the major limitations to macromolecular MRI contrast agents (MRI-CAs) is their slow clearance and associated decreased excretion of gadolinium (Gd(III)). The effect of coinjecting lysine to accelerate renal excretion of a macromolecular MRI-CA (generation-4 PAMAM dendrimer (G4D-(1B4M-Gd)64)) was investigated. The biodistribution and urine and fecal excretion in athymic mice was evaluated with and without lysine coinjection. 3D-dynamic-micro-MRI with G4D-(1B4M-Gd)64 was obtained with and without lysine coinjection, and the serial signal intensity (SI) change in the blood and organs was evaluated. When lysine was coinjected, urinary excretion of G4D-(1B4M-Gd)64 increased 5.4-fold compared to that without lysine, resulting in decreased renal accumulation of G4D-(1B4M-Gd)64 from 150% to 40% injected dose per gram (P < 0.001). On dynamic MRI with G4D-(1B4M-Gd)64, when lysine was coinjected, the kidney-to-blood SI ratio was significantly lower than that obtained without lysine (P < 0.001). When lysine was coinjected, the G4D-(1B4M-Gd)64 was excreted from the kidney intact.

Animals↗

PubMed2001

3D MR angiography of intratumoral vasculature using a novel macromolecular MR contrast agent.

Noninvasive methods to visualize blood flow in the intratumoral vasculature have not previously been studied. In the present study, the use of a novel intravascular MR contrast agent with a generation-6 polyamidoamine dendrimer core (G6-(1B4M-Gd)192; MW: 175kD) was investigated, and the vasculature in experimental tumors was visualized using 3D MR angiography (MRA). Xenografted tumors in nude mice of two different histologies-KT005 (human osteogenic sarcoma) and LS180 (human colon carcinoma)-were used to obtain 3D MRA using G6-(1B4M-Gd)192 and Gd-DTPA. The contrast MR sectional images were correlated with the corresponding histological sections. The intratumoral vasculature in the KT005 tumor was clearly visualized by 3D MRA, which became more evident with the growth of the tumor xenograft. In contrast, the intratumoral vasculature in the LS180 tumor was sparser and much less developed than that in KT005 tumors. Blood vessels with a diameter as small as 100 microm based on histology were visualized using 0.033 mmol Gd/kg of G6-(1B4M-Gd)192. In conclusion, intratumoral vasculature with a 100-microm diameter was visualized better using 3D MRA with G6-(1B4M-Gd)192 than with Gd-DTPA.

Animals↗

PubMed2001

Positive effects of polyethylene glycol conjugation to generation-4 polyamidoamine dendrimers as macromolecular MR contrast agents.

Macromolecules conjugated with polyethylene glycol (PEG) acquire more hydrophilicity, resulting in a longer half-life in circulation and lower immunogenicity. Two novel conjugates for MRI contrast agents were synthesized from a generation-4 polyamidoamine dendrimer (G4D), 2-(p-isothiocyanatobenzyl)-6-methyl-diethylenetriaminepentaacetic acid (1B4M), and one or two PEG molecules with a molecular weight of 20000 Da (PEG(2)-G4D-(1B4M-Gd)(62) (MW: 96 kD), PEG(1)-G4D-(1B4M-Gd)(63) (MW: 77 kD)). Their pharmacokinetics, excretion, and properties as vascular MRI contrast agents were evaluated and compared with those of G4D-(1B4M-Gd)(64) (MW: 57 kD). PEG(2)-G4D-(1B4M-Gd)(62) remained in the blood significantly longer and accumulated significantly less in the liver and kidney than the other two preparations (P < 0.01). Although the blood clearance was slower, PEG(2)-G4D-(1B4M-Gd)(62) was excreted more readily without renal retention than the other two preparations. In conclusion, the positive effects of PEG conjugation on a macromolecular MRI contrast agent were found to be prolonged retention in the circulation, increased excretion, and decreased accumulation in the organs.

Animals↗

PubMed2001

Novel liver macromolecular MR contrast agent with a polypropylenimine diaminobutyl dendrimer core: comparison to the vascular MR contrast agent with the polyamidoamine dendrimer core.

As MRI contrast agents, more hydrophobic molecules reportedly accumulate in the liver and thus are potentially useful as liver MRI contrast agents. In this study, a generation-4 polypropylenimine diaminobutane dendrimer (DAB-Am64), which is expected to be more hydrophobic than the generation-4 polyamidoamine dendrimer (PAMAM-G4D), was used to synthesize a conjugate with 2-(p-isothiocyanatobenzyl)-6-methyl-diethylenetriaminepentaacetic acid (1B4M) [DAB-Am64-(1B4M-Gd)(64)] for complexing Gd(III) ions. This DAB conjugate quickly accumulated in the liver and its characteristics were studied and compared with those of a PAMAM conjugate [PAMAM-G4D-(1B4M-Gd)(64)], which is known to be a useful vascular MRI contrast agent, in regard to its availability as a liver MRI contrast agent. DAB-Am64-(1B4M-Gd)(64) accumulated significantly more in the liver and less in blood than PAMAM-G4D-(1B4M-Gd)(64) (P < 0.001). Contrast-enhanced MRI with DAB-Am64-(1B4M-Gd)(64) was able to homogeneously enhance liver parenchyma and visualize both portal and hepatic veins of 0.5 mm diameter in mice. In conclusion, DAB-Am64-(1B4M-Gd)(64) is a good candidate for a liver MRI contrast agent.

Animals↗

PubMed2001

Pharmacokinetics and enhancement patterns of macromolecular MR contrast agents with various sizes of polyamidoamine dendrimer cores.

Four macromolecular contrast agents are synthesized to visualize small vessels by MRI using generation-3 (G3D), -4 (G4D), -5 (G5D), and -6 (G6D) polyamidoamine dendrimers conjugated to chelated gadolinium (Gd). The pharmacokinetics, enhancement patterns, and the ability of these constructs to visualize fine vessels is evaluated by dynamic MRI in relationship to their size. Gd-G6D and -G5D exhibit a prolonged high vascular (ventricular) signal intensity (SI) with high ventricle-to-organ SI ratios. The initial high vascular SI with Gd-G4D decreases to a value as low as that obtained with Gd-G3D and Gd-dimeglumine-diethylenetriaminepentaacetic acid (Gd-DTPA). Gd-G5D, -G4D, and -G3D show high renal SIs, and Gd-DTPA prominently enhances the skin. Gd-G6D and -G5D present fine vasculature significantly more clearly than Gd-G3D and -DTPA (P < 0.005). As the molecular size increases, the excretion of the 153Gd-conjugates is retarded. In conclusion, Gd-G6D and -G5D are retained in the blood and present fine vessels with high quality and detail, and should be adequate for visualizing small tumor vasculature.

Animals↗

PubMed2001

Polysplenia associated with semiannular pancreas.

We report CT images of an asymptomatic, adult case of polysplenia syndrome associated with semiannular pancreas, intestinal malrotation, preduodenal portal vein, and agenesis of the upper abdominal segment of the inferior vena cava with azygous continuation. This rare combination of abdominal abnormalities would be mainly caused by congenital malrotation of lower abdominal organs.

Abnormalities, Multiple↗

PubMed2001

Oviposition deterrent by female reproductive gland secretion in Japanese pine sawyer, Monochamus alternatus.

Adult females of Monochamus alternatus are known to use palpation to recognize oviposition scars that contain eggs and to be deterred from oviposition. This study investigated the oviposition-deterring activity of a jellylike secretion deposited by the females immediately after oviposition and methanol extracts of female reproductive organs in the laboratory. When females searching for oviposition sites encountered artificial oviposition scars, they stopped walking and drummed the surface and inside of the oviposition scars with their maxillary and labial palpi. When the females encountered the artificial scars plugged with the jellylike secretion, most of them left the scars after palpation. In contrast, when females encountered artificial scars not plugged with the secretion, most of them deposited single eggs through the scars. In another experiment, most females left artificial scars treated with methanol extracts of the spermathecal gland or other reproductive organs after palpation, but most of them oviposited through the scars treated with methanol alone. The results showed that females' recognition of egg-containing scars and departure from such scars were mediated by the chemical(s) produced by their reproductive organs.

Animals↗