Biomedical subjects

M Ikeda

Publications and source records attributed to M Ikeda.

At least 811 records · Page 45Linked to original sources

PubMed1996

Background exposure of general population to cadmium and lead in Tainan city, Taiwan.

Venous blood samples, 24-h total food duplicate samples, and rice samples were collected from 52 adult non-smoking women in the city of Tainan, southern Taiwan, in 1994, and analyzed for cadmium (Cd) and lead (Pb) by wet-digestion followed by graphite furnace atomic absorption spectrophotometry. Daily dietary intake was 10 micrograms for Cd and 22 micrograms for Pb as geometric means, of which Cd and Pb in rice accounted for 34% and 1.4% of daily Cd and Pb intakes, respectively. The counterpart values for blood were 1.11 ng/ml and 44.5 ng/ml for Cd and Pb, respectively. International comparison with recently published data suggests that the exposure to Cd in Tainan should be among the lowest in the world.

Adult↗

PubMed1996

In situ hybridization analysis of substance P receptor in the rat retina.

Substance P receptor is known to provide a principal interface between tachykinin peptides and tachykinin-sensitive cells in retinal circuitry and to produce several physiological functions such as excitation of ganglion cells. We reported results of in situ hybridization analysis of substance P receptor in rat retina using digoxigenin-labeled RNA probes to yield discrete cell labeling. Distinct hybridization signal was present in a great majority of ganglion cells that provide retinal fibers to a central target. It was also present in a subpopulation of amacrine cells. Following optic nerve crush, ganglion cells lost their hybridization signal in a time-dependent manner, while hybridization-positive amacrine cells were persistently seen. From the results, we identified the hybridization message as distinctly localized to two systems, output cells and intrinsic cells in retinal circuitry.

Animals↗

PubMed1996

Trehalase in the spermatophore from the bean-shaped accessory gland of the male mealworm beetle, Tenebrio molitor: purification, kinetic properties and localization of the enzyme.

Trehalase from the bean-shaped accessory glands of the male mealworm beetle, Tenebrio molitor, was purified by acid treatment, with subsequent chromatography on columns of DEAE-cellulofine and Sephacryl S-300. The molecular masses of the native and the denatured forms were estimated to be 43 and 62 kDa by gel filtration and SDS-PAGE, respectively, an indication that the trehalase may be composed of a single polypeptide. The optimum pH of the reaction catalyzed by trehalase was 5.6-5.8. The Km for trehalose was 4.4 mmol.1(-1). Immunohistochemical experiments with trehalase-specific antiserum showed that the enzyme was localized in one specific type of secretory cell in the bean-shaped accessory gland epithelium and within the semisolid secretory mass that was a precursor to the wall of spermatophore. SDS-PAGE and immunoblotting analysis revealed the presence of a polypeptide of about 62 kDa in the spermatophore. Immunohistochemical observations showed that the trehalase was located at the outgrowth in the anterior portion of the spermatophore. When a fresh spermatophore was immersed in phosphate-buffered saline it discharged sperm in the same manner as in the bursa copulatrix of the female. Before the rupture of the expanded bulb of the spermatophore, almost all of the trehalase had dissolved in the phosphate-buffered saline. The addition of validoxylamine A to the saline, a specific inhibitor of trehalase, did not affect the expansion and evacuation of the spermatophore. These results demonstrate that trehalase, synthesized by a specific type of secretory cell in the bean-shaped accessory gland epithelium, is actively passed into the lumen of the bean-shaped accessory gland and then incorporated into the spermatophore. Trehalase appears to be one of the structural proteins of the spermatophore, although the possibility can not yet be completely ruled out that the trehalase-trehalose system functions for the nourishment and/or activation of the sperm in the bursa copulatrix of the female.

Acetates↗

PubMed1996

The coagulofibrinolytic state of patients with primary varicose veins of the lower legs.

The relationship between a local hypercoagulable state and primary varicose veins of the lower legs was investigated by measuring the plasma levels of D-dimer (DD) and the thrombin-antithrombin-III complex (TAT) in 122 consecutive patients before treatment, and in 46 patients after surgical intervention and compression sclerotherapy. Elevated levels of DD and TAT were found in 25% and 20%, respectively, of the 122 patients, being significantly elevated in the patients with thrombophlebitis compared to the patients with no dermal symptoms, pigmentation, or stasis dermatitis. There was no significant difference in either parameter among eight groups of patients classified according to their valvular incompetence. The levels of DD and TAT were elevated before treatment in 25% and 20%, respectively, of 45 treated patients, but became significantly reduced after treatment. These results indicate that even though the local hypercoagulable state in varicose veins without thrombophlebitis is too subtle to be detected by systemic parameters such as DD and TAT, a local hypercoagulable state can be detected in a certain proportion of patients with venous stasis by these parameters.

Adult↗

PubMed1996

Toluene itself as the best urinary marker of toluene exposure.

Head-space gas chromatography (GC) and high-performance liquid chromatography (HPLC) (with fluorescence detectors) methods were developed for toluene (TOL-U) and o-cresol (CR-U) in urine, respectively. In order to identify the most sensitive urinary indicator of occupational exposure to toluene vapor (TOL-A) among TOL-U, CR-U, and hippuric acid in urine (HA-U), the two methods together with an HPLC (with untraviolet detectors) method for determination of HA-U were applied in the analysis of end-of-shift urine samples from 115 solvent-exposed workers (exposed to toluene at 4 ppm as geometric mean). Regression analysis showed that TOL-U correlated with TOL-A with a significantly higher correlation coefficient than did HA-U or CR-U. With regard to the TOL-A concentrations at which the exposed subjects could be separated from the nonexposed by the analyte, TOL-U achieved separation at < 10 ppm TOL-A, whereas both HA-U and CR-U did so only when TOL-A was 30 ppm or even higher. The ratio of the analyte concentrations at 50 ppm TOL-A to those at 0 ppm TOL-A was also highest for TOL-U. Overall, the results suggest that TOL-U is a better marker of exposure to toluene vapor than HA-U or CR-U.

Biomarkers↗

PubMed1996

Reduced cadmium and lead burden in Japan in the past 10 years.

OBJECTIVE: To investigate the current levels of exposure of the Japanese population to cadmium and lead, in comparison with the levels in 1980s. DESIGN: A nation wide survey was conducted in 1991-1994 (the 1990 study) in 19 study sites in Japan as a follow-up to a study conducted in 1979-1983 (the 1980 study). Blood samples and 24-h total food duplicates were collected from women who did not smoke or drink habitually. METHODS: Blood and food duplicates (after homogenization) were analysed for cadmium (Cd-B and Cd-F, respectively) and lead (Pb-B and Pb-F) by graphite furnace atomic absorption after wet-ashing. RESULTS: Altogether, 467 women volunteered for blood sampling. Of these women, 375 also gave food duplicates. Geometric mean (GM) Cd-B levels in the 1990 study were lower than the corresponding 1980 values in most study sites so that the 1990 grand GM (1.98 ng/ml) for Cd-B was significantly lower than the 1980 GM (3.58 ng/ml). This reduction in Cd-B was related to the reduction in Cd-F (GM for Cd-F was 38.0 micrograms/day in the 1980 study and 30.0 micrograms/day in the 1990 study). Dietary intake was almost exclusively the route of Cd burden among the populations studied. Both Pb-B and Pb-F also showed a remarkable reduction, i.e. from 33.9 ng/ml (1980 GM) to 23.2 ng/ml (1990 GM) in the case of Pb-B, and from 32.2 micrograms/day (1980 GM) to 7.1 micrograms/day (1990 GM) in the case of Pb-F. Pb-B, however, did not correlate with Pb-F either in the 1980 or the 1990 study, because Pb intake via inhalation of air remained significant when compared with dietary intake. CONCLUSION: The Cd burden in Japan has decreased markedly in the past 10 years, although it is still higher than in other countries. The Pb burden has been quite low.

Adult↗

PubMed1996

Fluorine-18 fluoro-2-deoxyglucose positron emission tomography in recurrent rectal cancer: relation to tumour size and cellularity.

The aim of this study was to assess the value of fluorine-18 fluoro-2-deoxyglucose (FDG) positron emission tomography in patients with recurrent rectal cancer, in relation to tumour size and cellularity. Thirty-seven patients (21 mean and 16 women; mean age, 55.4+/-9.58 years) with suspected recurrence of rectal cancer were studied. FDG uptake was quantified by the differential absorption ratio (DAR). In 29 patients magnetic resonance imaging was also performed. To evaluate the signal intensity of the lesion, the lesion to muscle signal intensity ratios (SIR) were calculated on T2-weighted images. In seven patients who received surgical treatment the DAR and SIR were compared with the tumour cellularity. All 32 patients with confirmed recurrence showed increased FDG accumulation in the mass (DAR=4.57+/-1.89) in comparison with low FDG accumulation in five patients with scar (DAR=1.17+/-0.43). There was a significant correlation (r=0.661, P<0.001) between the DAR and the tumour diameter. There was no correlation between the DAR and SIR, whereas there was a significant correlation (r=0.565, P<0.01) between the DAR corrected using count recovery coefficient (DAR*) and SIR. In the histopathological findings there was a tendency for the DAR* and SIR to correlate with tumour cellularity. It is concluded that the DAR of recurrent rectal cancer should be evaluated taking into consideration the tumour size and cellularity.

Deoxyglucose↗

PubMed1996

Gene expression of gonadotropin-releasing hormone in early pregnant rat and steroid hormone exposed mouse uteri.

While gonadotropin-releasing hormone (GnRH) or GnRH-like substance have been reported to exist in nonhypothalamic tissues such as placenta, gonads, and mammary gland, there have been no reports concerning the detection of GnRH mRNA in uterine tissue. In order to investigate the presence of GnRH in decidual tissues and its possible involvement in the regulation of placental function, we examined the gene for GnRH in the rodent uterus in early pregnancy and in nonpregnant animals treated with female sex steroids. Using RT-PCR and in situ hybridization we found GnRH mRNA transcripts in the rat uterus of 3rd and 6th day gestation and in the mouse uterus treated with estrogen and progesterone. In situ hybridization revealed that GnRH mRNA was localized in the endometrial stromal cells of the 3rd and 6th day of gestation. These results suggest the existence of GnRH gene expression in uterine stromal cells and its possible paracrine effect derived from the decidual cells.

Animals↗

PubMed1996

Regeneration of myelinated fiber after crush injury is retarded in sciatic nerves of mutant Japanese quails deficient in neurofilaments.

Regeneration of myelinated fibers in the sciatic nerve 2 weeks after crush injury was studied morphometrically in mutant Japanese quails deficient in neurofilaments and in normal quails (controls). There were fewer regenerated myelinated fibers per nerve at 10 mm (R1) and 20 mm (R2) distal to the crush site in mutants than in controls (P < 0.05). Both median and maximum diameters were smaller (P < 0.01) in mutants than in controls. On electron microscopy, transverse axonal area and axonal circumference were smaller (P < 0.001) at both R1 and R2 in mutants than in controls. The number of myelin lamellae was less (P < 0.01) in mutants than in controls at R1, but was similar at R2. There were fewer myelin lamellae in relation to axonal area in mutants than in controls at R1 (P < 0.0001) and R2 (P = 0.0032). The results indicate a retardation of both radial growth of axons and myelination around axons of the same size in mutants compared with controls. Such retardation may be explained by the deficiency of neurofilaments and the altered relationship between Schwann cell and axon in the mutant.

Animals↗

PubMed1996

Estimation of the size of the media necessary to construct a medical image database.

To estimate the size of the media necessary to construct a medical image database, a statistical analysis was made of the radiological data in our hospital information system database. The distribution of the total radiological image data storage required during one working day can be regarded as a normal distribution, and the distribution per patient was different from a normal one. Therefore, the mean amount required for the data storage of radiological images during one working day is very useful in estimating the data storage required for radiological images during a given number of working days.

Computer Systems↗

PubMed1996

Analysis of CAG trinucleotide expansion associated with Machado-Joseph disease.

There are currently some types of autosomal dominant cerebellar ataxias such as Machado-Joseph disease (MJD), spinocerebellar ataxia types 1-5 (SCA1-5), or hereditary dentatorubropallidoluysian atrophy. It is very important for these ataxias to be clinically differentiated, but that is sometimes difficult. In particular, the differential diagnosis between MJD and SCA1 is thought to be the most difficult. Recently, both MJD and SCA1 have been proven to be related to expansions of CAG trinucleotide in their causative genes. In this study, 20 cases of MJD in 13 unrelated Japanese families were genetically and clinically examined in comparison with 20 cases of age at onset- and duration-matched Japanese SCA1. The CAG repeat number of expanded MJD and SCA1 alleles was 72.2 +/- 3.1 (mean +/- SD, n = 20) and 47.3 +/- 4.4 (n = 20), respectively, and each repeat size was inversely correlated with age at onset in both MJD and SCA1. The repeat number in leukocytes increased from parents to children with acceleration of age at onset (anticipation) in MJD. In MJD, the number of CAG repeats in the expanded allele was lower in sperm than that of leukocytes, but was more in SCA1. However, the number of peaks in the expanded allele was greater in sperm than in leukocytes in both MJD and SCA1 (increased mosaicism level). MJD was clinically characterized by a relatively higher frequency of ocular signs such as eyelid retraction, bulging eyes, ophthalmoparesis, and nystagmus, spasticity in lower limbs, and sensory and urinary disturbances in contrast to the SCA1 patients except for slow eye movement. These results indicate that the expanded CAG repeat and clinical features are correlated in both MJD and SCA1, and MJD can be differentiated from SCA1 by clinical characteristics mentioned above as well as DNA analysis.

Adolescent↗

PubMed1996

Clinical characteristics of familial amyotrophic lateral sclerosis with Cu/Zn superoxide dismutase gene mutations.

We report clinical characteristics of familial amyotrophic lateral sclerosis (FALS) with 4 different missense point mutations in exons 2, 4, and 5 of the Cu/Zn superoxide dismutase (SOD) gene, that result in amino acid substitutions of histidine46 by arginine (H46R), leucine84 by valine (L84V), isoleucine104 by phenylalanine (I104F), and valine148 by isoleucine (V148I), in 5 Japanese families. Although features of progressive neurogenic muscular atrophy were common in patients of these families, patients of each family showed characteristic clinical features. FALS patients with the H46R mutation showed a benign clinical course and stereotype progression of muscular weakness and atrophy beginning from the legs. In FALS with the L84V mutation, while the clinical course of the disease was similar, the age at onset was younger in men than women. The patients with I104F showed wide ranges of age at onset and duration with ophthalmoparesis and sensory involvement in one patient. Those with the V148I mutation showed younger age at onset and variable first symptoms within the family. Although lower motor sign was evident in all cases, hyperreflexia varied from 0 to 100% among patients with the different mutations, and the Babinski sign was not observed in any case. Bulbar palsy was frequent with I104F, but not with H46R. SOD activity of the red blood cells was severely reduced with I104F and V148I, but was slightly reduced with H46R. These results suggest that familial ALS with different mutations of the Cu/Zn SOD gene each showed clinical characteristics, and that genetic mutations and clinical features are well correlated in familial ALS.

Adolescent↗

PubMed1996

alpha-Tocopherol pretreatment protects the endocrine function of grafts against ischemic damage during heterotopic pancreatic transplantation.

Post-ischemic injury is one of the most important problems affecting successful organ procurement and transplantation. The present study was performed to determine whether alpha-tocopherol can protect the endocrine function of pancreatic grafts against ischemia-reperfusion injury during rat heterotopic pancreatic transplantation. Rats with streptozotocin-induced hyperglycemia were used as recipients. The donor pancreas was removed and subjected to warm ischemia at 37 degrees C for 30, 60, 90 and 120 min, and then transplanted into a recipient. A 30-min period of warm ischemia did not impair the endocrine function of the pancreatic grafts, which was assessed by measuring the blood glucose levels and glucose decay constants (K), and a 60-min period of warm ischemia was considered to be the critical period for reversible tissue damage. Pretreatment with alpha-tocopherol (20 mg/kg/day, i.v.) for seven days before graftectomy significantly decreased blood glucose levels to less than 200 mg/dl and significantly increased K values in the recipient rats after transplantation when compared with placebo pretreatment. These results suggest that alpha-tocopherol pretreatment can protect the endocrine function of pancreatic grafts against injury due to warm ischemia followed by reperfusion.

Animals↗

PubMed1996

Comparison of clinical picture between Yusho/Yucheng cases and occupational PCB poisoning cases.

Literature review on clinical picture was made on two food poisoning episodes of Yusho and Yucheng in comparison with occupational PCB exposures. It was found that the dose-response relationship is quite different between Yusho/Yucheng patients and workers occupationally exposed to PCBs, when PCB levels in blood were taken as a common indicator of exposure intensity; the clinical manifestations were much severer in the former than in the latter, even when blood PCB levels were comparable. This conclusion is in support of the suggestions that chemicals such as polychlorinated dibenzofurans should have played an important role in the etiology of Yusho and Yucheng.

Food Contamination↗

PubMed1996

Inhibition of contractile tension by capsaicin in isolated rat papillary muscle.

1. We examined effects of capsaicin (10(-9) - 10(-5) M), a pungent agent extracted from red pepper, on the contractile tension of rat ventricular papillary muscles stimulated at various cycle lengths (0.2, 0.5, 1, 2 and 5 sec). 2. Capsaicin produced a marked concentration-dependent decrease in the amplitude, the rate of rise (dp/dt) and the rate of relaxation (dr/dt) of the tension. 3. However, the half relaxation time and the time to peak tension of the tension were slightly affected by the agent. 4. The negative inotropic effect of capsaicin was stimulus cycle length (CL) dependent. In particular, IC50 (50% inhibitive concentration) of the agent in the amplitude of the tension was stimulus CL dependent. That is, the values of IC50 were around 10(-7) M at longer CLs (1, 2 and 5 sec), and the value of IC50 at CL 0.2 sec was 4 x 10(-6) M. 5. These capsaicin-induced negative inotropic effects were reversible. Other studies from our laboratory show that the negative inotropic effects may be largely due to a decrease in Ca2+ current.

Animals↗

PubMed1996

Capsaicin does not inhibit the intracellular calcium handling process in rat ventricular papillary muscle.

1. We studied the effects of capsaicin, a pungent agent extracted from red pepper, on rested-state contraction (RSC) of isolated rat ventricular papillary muscles. 2. The RSC was induced by stimulation, after a rest interval of 5 sec to 10 min, after the twitch tension of the muscle preparation stimulated at the regular stimulus frequency of cycle lengths of 5, 1 or 0.2 sec attained the steady state. 3. Drug effects were evaluated on the RSC in the presence of capsaicin 10(-5) M, caffeine 10(-2) M or ryanodine 10(-7) M, respectively. 4. All drugs inhibited the RSC but to different degrees. Ryanodine was the most effective in inhibiting RSC, followed by caffeine and capsaicin, in that order. However, the inhibitory mode varied, depending on the drugs. 5. These findings suggest that capsaicin may not inhibit the function of intracellular Ca2+ store in rat cardiac muscle.

Alkaloids↗

PubMed1996

Possible release of nitric oxide from cholinergic axons in the thalamus by stimulation of the rat laterodorsal tegmental nucleus as measured with voltammetry.

By means of the differential direct current voltammetry technique with carbon fiber electrodes in urethane-anesthetized rats, we monitored nitric oxide (NO) concentrations in the thalamus in the basal condition and following electrical stimulation of the laterodorsal tegmental nucleus (LDT), whose neurons have the strongest activity of NADPH-diaphorase, or NO synthase, together with acetylcholine. NO levels, measured as the height of the peak at +970-1000 mV in the voltammetry (NO was soon oxidized in vivo to be detected at the voltage of this peak, so that NO levels in this report are, in the strict sense, levels of the oxidized metabolites reflecting very possibly those of NO in physiological conditions; see Section 2, Methods), increased just after repetitive stimulation of the LDT. Stimulation of the surrounding areas or the cerebellum produced virtually no change in NO levels. An intravenous injection of L-nitroarginine methyl ester reduced the basal level of NO, but stimulation of the LDT still increased NO levels, which may be due to very strong activity of NO synthase in the LDT neurons. These results are consistent with the notion that NO can be released from axons of the LDT neurons by their excitation.

Animals↗

PubMed1996

Weight reduction regresses left ventricular mass regardless of blood pressure level in obese subjects.

The effects of weight reduction on left ventricular mass in obese normotensive and hypertensive subjects were investigated. Previous studies have shown that weight reduction in hypertensive (HT) obese patients is associated with decreased left ventricular mass (LVM) and decreased blood pressure (BP). This study was performed to examine whether weight reduction would also regress LVM in normotensive (NT) obese subjects and to clarify the mechanisms of these effects if they occurred. A weight-reduction program consisted of mild exercise and mild hypocaloric intake. M-mode echocardiography was performed to estimate the LVM. After the 12-week intervention, the mean reductions in body weight (BW) in the NT (n = 11) and HT (n = 11) groups were 4.9 kg (p < 0.005) and 4.6 kg (p < 0.0005), respectively. Systolic, diastolic, and mean BP were significantly reduced by 13, 9, and 11 mm Hg, respectively, in the HT group. By contrast, no significant changes in systolic, diastolic, or mean BP were observed in the NT group. LVM was significantly reduced from 176 +/- 26 gm to 159 +/- 26 gm (p < 0.05) in the HT group and from 167 +/- 33 gm to 145 +/- 34 gm (p < 0.02) in the NT group. These results suggest that weight reduction in obese subjects by mild exercise and mild hypocaloric intake can lead to a reduction in LVM, regardless of whether the subjects have normal or high blood pressure.

Adult↗