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Biomedical subjects

M Kikuchi

Publications and source records attributed to M Kikuchi.

At least 1,261 records · Page 70Linked to original sources
PubMedDate not supplied

Protective effect of selenium on the inhibition of erythrocyte 5-aminolevulinate dehydratase activity by tin.

The protective effect of selenium (Se) on the inhibition of erythrocyte 5-aminolevulinate dehydratase (ALAD) activity by tin (Sn) was examined in mice. When mice were intraperitoneally (i.p.) administered 10 mumol/kg of stannous chloride, the activity of erythrocyte ALAD decreased to 35% of control. When more than an equimolar dose of sodium selenite was injected i.p. simultaneously with Sn, the ALAD activity was completely protected. Mortalities and weight gains of mice treated with Se were also reduced when Sn was administered simultaneously.

Animals↗
PubMedDate not supplied

Blood pressure changes associated with hyperinsulinemia or long-standing diabetes mellitus in spontaneously hypertensive rats.

We studied the long-term change in blood pressures of spontaneously hypertensive rats (SHR) treated neonatally with streptozotocin (STZ). Two-day-old male SHR were injected intraperitoneally with 37.5-75.0 mg/kg STZ or with vehicle as control. STZ-treated SHR were divided into mildly or severely diabetic groups according to the nonfasting plasma glucose level at age 12 weeks (the former less than 300 mg/dl, the latter greater than or equal to 300 mg/dl). In the mildly diabetic group (MD) (n = 5), body weight increased and nonfasting plasma glucose was normalized. At 52 weeks of age, fasting plasma glucose levels were lower than controls owing to hyperinsulinemia, and insulinomas were found in 60% of rats. The systolic blood pressure (SBP) as measured by a tail-cuff method, decreased after 40 weeks, and the mean BP from 44 to 52 weeks (188 +/- 4 mmHg) was significantly lower than that in the control group (209 +/- 3 mmHg, p less than 0.01). In the severely diabetic group (SD) (n = 6), hyperglycemia persisted until 52 weeks, although its severity became less marked. BP in the SD group increased after 36 weeks, and the mean BP from 44 weeks to 52 weeks (224 +/- 5 mmHg) was significantly higher than control (p less than 0.05). The present study demonstrated that hypertension was ameliorated in SHR associated with hyperinsulinemia, and deteriorated with long-standing diabetes mellitus.

Animals↗
PubMedDate not supplied

Risk factors for development of proteinuria in NIDDM analyzed by Poisson regression.

To clarify the time dependency of risk factors for the development of diabetic nephropathy, we applied Poisson regression to the analysis of 7167 person-year data in 1447 patients with non-insulin-dependent diabetes mellitus (NIDDM) who were initially free of proteinuria. Significant predictors were found to be annual mean fasting blood glucose (FBG) level, male gender, duration, and age at diagnosis. Hyperglycemia was more influential, while duration was less in the previous year of development of proteinuria than at the initial visit. When more information during longer-year data was used as average, the contribution of FBG level was enhanced. Current age was less associated than was age at diagnosis. Thus, Poisson regression seems to be useful for the analysis of risk variables in chronic diseases.

Blood Glucose↗
PubMedDate not supplied

Secondary alexithymia as a state reaction in panic disorder and social phobia.

In a 6-month follow-up study, a change in alexithymia was examined in two samples of 26 patients with panic disorder and 24 patients with social phobia. Before psychiatric treatment, the prevalence rate of alexithymia, measured by the 20-Item Toronto Alexithymia Scale (TAS-20), was higher for both panic disorder (54%) and social phobia (58%) groups than for healthy persons (15%). After treatment, scores on the alexithymia constructs of difficulty identifying feelings and difficulty describing feelings significantly decreased in panic disorder and social phobia patients. The overall decrease in measures of alexithymia in both groups was significantly related to reduction in anxiety, but not depression. The results suggest that secondary alexithymia related to anxiety exists as a state reaction in patients with panic disorder and social phobia.

Adult↗
PubMedDate not supplied

Atrial natriuretic peptide in aged patients with iron deficiency anemia.

Anemia is a common disease in elderly people. However, since hemoglobin concentration often decreases subclinically with aging because of nutritional impairment, its pathological significance is unclear. To investigate the pathological significance of low hemoglobin concentration, we studied the relation between hemoglobin levels and arrhythmia, as well as circulatory parameters. Arrhythmia was detected by Holter type ambulatory electrocardiography in 42 elderly people (aged 60 or over) living in a nursing home. Plasma concentrations of human atrial natriuretic peptide (hANP) after iron therapy were determined by immunoradiometric assay. Changes in circulatory parameters in elderly people with iron deficiency anemia were examined. Supraventricular and ventricular premature contractions significantly increased in elderly people with low hemoglobin concentrations or hematocrit. hANP increased significantly as the hemoglobin concentration decreased in 22 elderly people. Of these 22 subjects, 11 showed a low serum concentration of iron, and were administered ferrous salts. No side effects, such as nausea, occurred. After iron supplementation, the average hemoglobin level increased from 9.0 to 10.5 g/dl, and the average hANP level was reduced from 58.3+/-23.5 to 41.2+/-27.9 pg/ml, which was statistically significant by Wilcoxon's signed rank sum test. The increase in the hemoglobin level inversely correlated with the hANP level. Heart rate, blood pressure and body weight of subjects decreased significantly after iron supplementation therapy. Although hemoglobin levels were increased by iron supplementation therapy after a long period of anemia, the duration of the period with low hemoglobin levels showed no significant relation to initial hANP concentration. In conclusion, low hemoglobin levels induced secretion of hANP, and treatment of iron deficiency might exert favorable effects on the circulatory system.

Journal Article↗
PubMedDate not supplied

Role of protein kinase a pathway in epidermal growth factor-induced liver cell repair.

To gain a better understanding of the mechanisms that control the repair process in the injured liver, the actions of epidermal growth factor (EGF) and protein kinase A (PKA) were studied. Normal rat liver cells (clone 9) were grown to confluence. Standardized excisional wounds were made with a razor blade. The extent of hepatocyte migration into the wound was measured and determined at specific time intervals using a computerized digital analyzing system. Immunostaining of F-actin was performed with a fluorescein-labeled phalloidin. EGF significantly stimulated liver cell migration, whereas specific EGF-neutralizing antibody inhibited the EGF-induced migration. Agents that activate PKA at different stages of the PKA activation pathway, including 3-isobutyl-1-methylxanthine (IBMX), forskolin, and cholera toxin, inhibited EGF-induced migration. EGF triggered formation of actin stress fibers. PKA-activating agents inhibited actin stress fiber formation and stretching of cells at the wound margin. The following conclusions were drawn: (1) In excisional wounds of hepatocyte monolayers, both EGF and PKA exert action on actin microfilaments, which are stretched by EGF and inhibited by PKA; (2) the enhanced repair of wounded hepatocyte monolayers by EGF is blocked by activation of the PKA pathway at various levels; and (3) these actions of EGF and PKA indicate their important regulatory roles in controlling the rate of hepatocyte migration and restitution following the creation of excisional wounds.

Animals↗
PubMedDate not supplied

Acceleration of wound contraction and healing with a photocrosslinkable chitosan hydrogel.

Application of ultraviolet light irradiation to a photocrosslinkable chitosan aqueous solution resulted in an insoluble, flexible hydrogel like soft rubber within 60 seconds. In order to evaluate its accelerating effect on wound healing, full-thickness skin incisions were made on the backs of mice and subsequently a photocrosslinkable chitosan aqueous solution was added into the wound and irradiated with UV light for 90 seconds. Application of the chitosan hydrogel significantly induced wound contraction and accelerated wound closure and healing compared with the untreated controls. Histological examination also showed an advanced contraction rate on the first 2 days and tissue fill rate on days 2 to 4 in the chitosan hydrogel-treated wounds. Furthermore, in cell culture studies, chitosan hydrogel culture medium supplemented with 5% fetal-bovine serum was found to be chemoattractant for human dermal fibroblasts in an invasion chamber assay using filters coated with Matrigel and in a cell migration assay. Due to its ability to accelerate wound contraction and healing, chitosan hydrogel may become accepted as an occlusive dressing for wound management.

Animals↗
PubMedDate not supplied

The rare red cell phenotype Gerbich negative in Japanese.

Two Japanese propositi with the rare Gerbich -negative (Ge-) phenotype were found by screening serum of donors for antibodies. These are the first two examples of Ge negative in Japanese. Both had the Gerbich type of Ge-negative phenotype (Ge: -1, -2, -3,), showed some depression of Kell system antigens, and had anti-Ge in their sera. The parents of each of the propositi were first cousins, and one of the propositi had two Ge-negative siblings.

Adolescent↗
PubMedDate not supplied

Treatment planning for capacitive regional hyperthermia.

Capacitively coupled hyperthermia devices are widely in use, mainly in Asian countries. In this paper, a comprehensive treatment planning system, including a Specific Absorption Rate (SAR) and thermal model for capacitively coupled hyperthermia, is described and demonstrated using a heterogeneous patient model. In order to accurately model a hyperthermia treatment, simulation at high resolution is mandatory. Using the quasi-static approximation, the electromagnetic problem can be solved at high resolution with acceptable computational effort. The validity of the quasi-static approximation is demonstrated by comparing the Maxwell solution of a phantom problem to the quasi-static approximation. Modelling of capacitive hyperthermia of the prostate reveals the difficulty of heating deep-seated tumours in the pelvic area. Comparison of the SAR distribution in the heterogeneous patient model and a patient shaped agar phantom shows a shielding effect of the pelvic bone and the influence of the fat-muscle distribution. It is shown that evaluation of capacitive hyperthermia with agar phantoms leads to overly optimistic conclusions. Therapeutic relevant tumour temperatures can only be obtained by permitting temperature extrema in normal tissue. This concurs with clinical practice, where treatment-limiting hot spots restrict the tumour temperature. It is demonstrated that the use of very cold overlay bolus bags has only a very superficial effect. The presented model can be used for individual treatment planning and optimization, for the evaluation of capacitive applicator modifications and comparison with other devices.

Electromagnetic Fields↗
PubMedDate not supplied

Determining the temperature distribution of swine aorta with simulated atheromatous plaque under pulsed laser irradiation: an experimental attempt to detect the vulnerability of atherosclerosis.

We developed a method to determine the temperature distribution of swine aortas with simulated atheromatous plaques in order to measure the temperature of atherosclerotic lesions. The inflammation associated with temperature elevation is considered to be one of the aggravating mechanisms of atherosclerosis resulting in fissuring or rupture of atheromatous plaques. The temperature distribution of plaques covered by fibrous caps cannot be measured by conventional thermistors. Indocyanine green (ICG) solution was injected into the subintima of swine aorta to simulate the light absorption coefficient of human atheromatous plaques. The temperature distribution was calculated from measured temperature changes of the aortic intima under pulsed laser irradiation. The aorta was heated from the adventitial side with a halogen lamp to simulate the temperature elevation derived from inflammation. The temperature distribution of the aorta was obtained by solving the heat transfer equation using the surface layer thickness (corresponding to the fibrous cap thickness). The surface layer thickness can be calculated using the following working formula: D(microm)=1363-398DeltaTs+35DeltaTs(2), where AT, denotes intimal surface temperature change under pulsed laser irradiation. The calculated temperature of the ICG layer (corresponding to the atheromatous core) correlated well with the measured temperature (r=0. 97, p<0.0001).

Animals↗
PubMedDate not supplied

The non-contact monitoring of heart and respiratory rates using laser irradiation: an experimental simultaneous monitoring with and without clothes during biochemical hazards.

The purpose of this study is to develop a non-contact method to evaluate the heart and respiratory rates simultaneously using a single optical sensor which can be used without the removal of clothes before a decontamination procedure in biochemical hazards. We measured the heart and respiratory rates with and without clothes to assess the vital sign monitoring before decontamination. In order to monitor the heart and respiratory rates of rabbits simultaneously, the respiratory and cardiac peaks were separated using fast Fourier transform from a 5 mW helium-neon laser (wavelength 632.8 nm) reflected off the chest walls of rabbits. A cloth (50 mm x 50 mm, 2 mm thick) was placed on the chest of the rabbits to simulate the vital sign monitoring with clothes. The heart rate measured using this method agreed with the rate derived from an electrocardiogram (r = 0.82, p<0.05). The respiratory rate correlated with the manually measured respirator rate (r = 0.93, p<0.05). This method appears promising as a non-contact method for monitoring the heart and respiratory rates of patients under biochemically hazardous conditions.

Animals↗
PubMedDate not supplied

Development of a continuous temperature mapping system using a deep body thermometer.

To determine continuous body temperature distribution, an inexpensive temperature mapping system was developed using a deep body thermometer adopting the finite-element method. A stripe with 16 thermocouples was wrapped around the waist of rats to measure body surface temperatures (the boundary conditions). The abdominal deep temperature of the rats was measured from the dorsum using the thermal compensation probe of a deep body thermometer. The abdominal temperature of the rats was mapped by solving a heat conduction equation using surface and deep temperatures obtained in real time. The temperature measured with a thermocouple inserted into the abdominal centre of the rats correlated well with the calculated temperature (r = 0.93, p < 0.01). The system is low cost and simple to use compared with the magnetic resonance temperature mapping system. Our temperature mapping system could potentially result in improved management of patients in critical care medicine.

Abdomen↗
PubMedDate not supplied

A new method to detect systemic inflammatory response syndrome by continuous monitoring system: an experimental study in rats.

A continuous monitoring system was designed for detection of systemic inflammatory response syndrome (SIRS) using spectrum analyser and local temperature mapping system with deep body thermometer. This method demonstrated significant increases of heart and respiratory rates and deep body temperature from normal levels within 120 minutes after lipopolysaccharide administration in rats. Our monitoring system appears promising for clinical detection of SIRS in the early stages to prevent multiple organ failure.

Animals↗
PubMedDate not supplied

Determination of terbium in organs of mice administered terbium chloride: comparative study of fluorometry and atomic absorption spectrometry.

The determination of terbium (Tb) in organs by fluorometry and atomic absorption spectrometry (AAS) was investigated. The organs of mice were ashed before the instrumental applications. The fluorometric measurement of Tb was performed after formation of a complex with dipicolinate. The detection limit was 0.1 micrograms/mL and the coefficient of variation was less than 5% (N = 6). AAS measurement of Tb was carried out with a pyrolytic graphite furnace. The detection limit by AAS was 1 microgram/mL. The concentrations of Tb in various organs of mice intraperitoneally administered TbCl3 at doses of 10, 50, and 250 mg Tb/kg were measured by both methods. The values obtained from each organ were dependent on the dose. High concentrations of Tb were found in spleen, pancreas, and seminal vesicle; lesser amounts were found in liver and testis. The correlation coefficient for both methods was high; r = 0.991 (N = 20) in liver and r = 0.988 (N = 20) in pancreas.

Animals↗
PubMedDate not supplied

Induction of human leukocyte antigen-A26-restricted and tumor-specific cytotoxic T lymphocytes by a single peptide of the SART1 antigen in patients with cancer with different A26 subtypes.

Peptide antigens available for use in specific immunotherapy of patients with cancer have not been fully determined. Although the authors have reported the SART1 gene encoding epitopes recognized by HLA-A2601-restricted and tumor-specific cytotoxic T lymphocytes (CTLs), the HLA-A26 allele is mainly subdivided into A2601, A2602, and A2603 subtypes. In this study, the authors attempted to determine whether the SART1-derived peptide at position 736-744 (KGSGKMKTE) is suitable to induce HLA-A26-restricted and tumor-specific CTLs in patients with cancer who have these subtypes. This peptide induced the HLA-A26 subtype-restricted and tumor-specific CTLs in HLA-A2601+ or HLA-A2603+ peripheral blood mononuclear cells, respectively. It also induced the HLA-A26-restricted CTL activity in HLA-A2602+ peripheral blood mononuclear cells. Therefore, this peptide could be useful for specific immunotherapy of patients with cancer who have any of the three HLA-A26 subtypes.

Antigens, Neoplasm↗