PubMed Health⌕ Search

Biomedical subjects

M Mizobuchi

Publications and source records attributed to M Mizobuchi.

At least 55 records · Page 3Linked to original sources
PubMed1993

Increase of plasma adrenocorticotrophin and cortisol in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated dogs.

Neuroendocrine abnormality of the hypothalamic-pituitary-adrenal axis was investigated in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated dogs as a model of Parkinson's disease. Blood samples were collected every 4 h for 3-4 days before MPTP treatment, around 2 and 4 weeks after the treatment of MPTP (2.5 mg/kg). Adrenocorticotrophin (ACTH) and cortisol concentrations in plasma were determined by radioimmunoassay. The concentrations of plasma ACTH and cortisol increased by 40% and 60% after MPTP treatment, respectively. Circadian rhythms of neither plasma ACTH nor cortisol concentrations were observed in both MPTP-treated and control dogs. This high hypothalamic-pituitary-adrenal function in MPTP-treated dogs suggests that MPTP may influence the activity of the hypothalamic neurons of the dog.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1993

Quantitative and sensitive northern blot hybridization using PCR-generated DNA probes labeled with digoxigenin by nick translation.

Northern blot hybridization is one of the most convenient methods of detecting an mRNA. Nonradioactive Northern blotting using digoxigenin (DIG) is becoming widely applied because it is rapid and safe. Previous studies have indicated that DIG-labeled RNA probes are suitable for Northern blot hybridization. Here, the application of PCR-generated double-stranded DNA probes labeled with DIG by nick translation is described. DNA probes were synthesized by PCR, then labeled with DIG by nick translation. Northern blot hybridization was performed using the DIG-labeled DNA probes, and the signals were detected by means of a chemiluminescent reaction. A low amount of DIG-dUTP in the labeling reaction resulted in excellent Northern blots with low background. Densitometric analysis of the blots showed that the mRNA concentrations could be determined by densitometric analysis. The sensitivity of the DIG-Northern system was comparable to Northern blotting using 32P and was sufficiently sensitive to detect low-abundance mRNA.

Animals↗
PubMed1992

Disappearance of circadian rhythms in Parkinson's disease model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in dogs.

Administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to dogs produces clinical, pathological and neurological features in dog resembling human Parkinson's disease. Using this animal model, we studied the changes in diurnal rhythms of urine volume, creatinine in urine, and vasopressin, aldosterone and renin activity in plasma. Before MPTP treatment, urine volume showed a peak between 17.00 and 1.00 and plasma vasopressin concentration also showed a clear circadian rhythm with a peak at 13.00 and a minimum level at 5.00. Two weeks after MPTP treatment (2.5 mg/kg i.v.), the rhythm of urine volume disappeared and that of vasopressin became less clear. Plasma renin activity increased 2 and 4 weeks after MPTP treatment. The increase was, however, not enough to change the concentration of plasma aldosterone. We examined the effect of L-3,4-dihydroxyphenylalanine (levodopa), on the circadian pattern of urine volume and vasopressin attenuated by MPTP. Levodopa (4 mg/kg/day) was administered orally every day from the first week after MPTP treatment. The circadian rhythms of urine volume and vasopressin reappeared within one week after the start of levodopa administration.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1992

A rapid and simple method for labeling short DNA fragments using Taq polymerase.

This report describes a new method for labeling PCR-generated short length (60-120 bp) double-stranded DNA fragments for use as hybridization probes. The method utilizes gene-specific primers identical to those for PCR generation of non-radioactive DNA fragments. Radioactive probes are synthesized by Taq DNA polymerase without using PCR. Single-stranded (sense or antisense) and double-stranded probes can be individually prepared by selection of the appropriate primers. The labeling reaction reached maximum incorporation within 30 min with mean specific activities of 1.05 x 10(9) dpm/microgram (antisense single-stranded), and 1.62 x 10(9) dpm/microgram (double-stranded) were obtained using templates 69-117 of nucleotides. This method offers a simple and rapid means of generating antisense probes for Northern blot analyses and double-stranded probes for Southern blot analyses that provide highly intense signals with low background.

Animals↗
PubMed1991

Tissue-specific transcription initiation and effects of growth hormone (GH) deficiency on the regulation of mouse and rat GH-releasing hormone gene in hypothalamus and placenta.

Hypothalamic GRH gene expression has been shown to be negatively regulated by GH in both rat and mouse. The recent reports of different 5' untranslated sequences in mouse GRH cDNA from hypothalamus and placenta have raised the possibility of tissue-specific regulation of the GRH gene. To provide support for this possibility, we have studied rodent models with GH deficiency due to genetic defects in the pituitary. Complementary DNA probes for the hypothalamic and placental 5' regions were used to determine the tissue specificity of each mRNA. Although the hypothalamic form of GRH mRNA was detected in placenta, it constituted less than 0.7% of total placental GRH mRNA. A placental 5' probe (based on the previously reported sequence) hybridized only with a larger mRNA species and was not tissue specific, indicating that it was not related to GRH and was derived possibly from a cloning artifact. The correct 5' sequence of mouse placental GRH cDNA was determined and shown to be distinct from both that previously reported and the hypothalamic sequence. Although the placental form of GRH mRNA was detected in hypothalamus using the polymerase chain reaction, its levels were undetectable by Northern blotting. The 5' end of rat placental GRH cDNA was similarly sequenced and shown to exhibit no homology with the rat 5' hypothalamic sequence, but a high degree of homology with the corresponding mouse placental sequence. In GH-deficient dwarf (dw/dw) rats, hypothalamic GRH mRNA levels were significantly increased above control levels in both females and males, and pregnancy did not alter the levels in either (dw) or control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Carotid-cavernous fistula successfully treated with embolization and radiation therapy: report of three cases].

Three cases of mixed internal and external carotid-cavernous fistula (CCF) were successfully treated with embolization of feeders from the external carotid artery (ECA) and focal irradiation to the cavernous sinus (CS). Cases 1 and 2 were females, 63 and 69 years old respectively, both with spontaneous left CCF. Case 3 was a 55 year old male with posttraumatic left CCF. Symptoms of case 1 were double vision, left chemosis and exophthalmos; those of case 2 were double vision, left retroobital pain, left forehead dysesthesia and blurred vision; and case 3 complained of double vision, left chemosis, left exophthalmos and pulsatile tinnitus. In all three cases, angiography disclosed left CCF fed by ipsilateral dural branches from the internal maxillary artery (IMA) and the internal carotid artery (ICA). In case 1, small branches from the ascending pharyngeal artery also fed the CS. In cases 2 and 3, feeders from the ECA were arising only from branches of the IMA. In case 3, hypertrophy of the meningohypophyseal trunk was visible. In cases 1 and 2, although the CS was opacified, feeders from the ICA were not clearly visible. Embolizations of branches of the IMA were performed in all cases using Ivalon under selective catheterization. In case 1, symptoms partially improved, but in cases 2 and 3, visual symptoms were transiently aggravated. Focal irradiation to the CS was done with total doses of 30, 30 and 40 Gy each for cases 1, 2, and 3 respectively. In case 1, clinical symptoms gradually improved about one third way through irradiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

[Evaluation of cardiac function during KCl-induced paralytic attack in the patients with normokalemic periodic paralysis].

Some reports have been written about hypokalemic periodic paralysis dealing with cardiac dysfunction and arrhythmia during the paralytic attack. However, no reports have been written about the cardiac function during the attack in cases of normokalemic periodic paralysis. So, we investigated cardiac function in two patients with normokalemic periodic paralysis. A 3.0 g dose of KCl was administered orally to the patients (1 male, 1 female) and 10 healthy volunteers (5 males, 5 females). Cardiac function by using ejection time (ET)/pre-ejection period (PEP), grasping power, and the level of plasma catecholamine were measured during the paralytic attack. Changes in the patients were compared with those in the volunteers. Next, a 3.0 g dose of KCl was administered to the patient, followed by intravenous dosing of 10% NaCl (50 ml) after which ET/PEP and grasping power measured. Lastly, a 60 mg dose of diltiazem, a 10 mg dose of nifedipine or a 80 mg dose of verapamil were administered, followed by a 3.0 g dose of KCl after which ET/PEP and grasping power were measured again. Thirty minutes after the administration of KCl, the grasping power decreased remarkably, from 32.0 kg to 17.0 kg in the male patient and from 30.0 kg to 20.0 kg in the female patient. By contrast, the ET/PEP showed a clear increase, from 3.47 to 6.17 in the male patient and from 2.84 to 5.45 in the female patient. Grasping power of the volunteers, however, did not change remarkably (avg. 40.3 kg before vs. 40.9 kg after in the males and avg. 26.9 kg before vs. 26.0 kg after in the females) and ET/PEP of the volunteers did not change remarkably (avg. 3.37 before vs. 3.17 after in the males and avg. 3.30 before vs. 3.43 after in the females). No significant changes were found in the levels of plasma catecholamine during the paralytic attack.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Insulin-like growth factor I (IGF-I) distribution in the tissue and extracellular compartment in different regions of rat brain.

The regional distribution of insulin-like growth factor I (IGF-I) was examined in the tissue and extracellular compartment of rat brain. The tissue content of IGF-I was the highest in the pituitary gland, followed by the olfactory bulb, upper brainstem, cerebellum, striatum, hippocampus, lower brainstem, and cerebral cortex. The extracellular concentration was studied by intracerebral microdialysis technique, and the highest content was found in the hippocampus, followed by the olfactory bulb, hypothalamus, cerebellum, striatum, and cerebral cortex. The tissue and extracellular contents were significantly correlated in the olfactory bulb, hypothalamus, cerebellum, striatum, and cerebral cortex. IGF-I might act by paracrine and/or autocrine regulatory mechanisms in these regions.

Animals↗
PubMed1990

High concentration of free trimethyllysine in red blood cells.

A high concentration of a basic unidentified amino compound was found in the blood of rats. It was isolated and identified as N epsilon,N epsilon,N epsilon-trimethyllysine by paper chromatography, thin-layer chromatography, high-performance liquid chromatography and amino acid analyzer. It was localized exclusively in red blood cells in the blood of rats. Free trimethyllysine was also determined in the liver, kidney, spleen, brain, muscle, heart and testis of rat. The concentration of free trimethyllysine in red blood cells was more than 10-times as high as that in the other tissues. This compound in red blood cells was found in different species of animals. The relationship between this free trimethyllysine and carnitine was discussed.

Amino Acids↗
PubMed1990

Purification of human liver guanase and characterization of antibody against it by immunoblotting.

Guanase was purified from human liver and its specific antibody was raised in rabbits. The enzyme was purified 1200-fold from the crude liver extract; the specific activity of the purified enzyme was 91.50 units/mg. The purified enzyme gave two distinct peaks on high pressure liquid ion exchange chromatography. The materials in both peaks had a molecular weight of 100,000, and were concluded to be isozymes with different pH optima for guanine. The antiserum completely inhibited the activity of the liver enzyme. It formed a single precipitin line with the human liver extract. On immunoblotting, it bound specifically to the one band with guanase activity, but to no other bands of protein. Thus, this antiserum for human liver guanase should be suitable for use in immunohistochemical demonstration of guanase and determination of this enzyme by radioimmunoassay.

Aminohydrolases↗
PubMed1990

In vivo analysis of extracellular proteins in rat brains with a newly developed intracerebral microdialysis probe.

Peptides and proteins in the extracellular space in the central nervous system were investigated in vivo using an intracerebral microdialysis probe. The molecular cut-off of the hollow fiber which was used for the probe was approximately 100 kDa. We examined recovery rates of several compounds in vitro. The recovery rates of proteins and peptides were between 7-28%, with the exceptions of substance P and insulin-like growth factor I. The recovery rates of monoamines and their metabolites were 22-40%. In in vivo studies, two major proteins with apparent molecular weights of 62 kDa and 12 kDa, and several minor proteins (28 kDa, 43 kDa, 52 kDa and 70 kDa) were detected by SDS-polyacrylamide gel electrophoresis in the dialysate from a probe implanted in the striatum of anesthetized rats. These results suggest that the newly developed, intracerebral microdialysis probe might be useful for investigating the dynamic changes of peptides and proteins in the central nervous system.

Animals↗
PubMed1986

Identification of novel N-glucuronides in rat bile after administration of 450191-S, a 1H-1,2,4-triazolyl benzophenone derivative.

5-[2-Aminoacetamido)methyl]-1-[p-chloro-2-(o-chlorobenzoyl)phenyl] -N,N-dimethyl-1H-s-triazole-3-carboxamide hydrochloride dihydrate (450191-S) is a ring-opened derivative of 1,4-benzodiazepine, which is activated by desglycylation and subsequent cyclization. After 450191-S administration, rat bile contained three novel conjugates which released active metabolites possessing the 1,4-benzodiazepine structure through beta-glucuronidase hydrolysis. Since the released metabolites have no functional groups to conjugate with glucuronic acid, we speculated that the aglycone might be the ring-opened form of 1,4-benzodiazepine which spontaneously cyclizes after the release of glucuronic acid. This possibility was tested by chemically reducing the ketone group of the ring-opened 1,4-benzodiazepine glucuronate conjugates, which would prevent the spontaneous ring closure reaction after the release of the glucuronic acid moiety. The NaBH4 reduction of the ketone of the benzophenone moiety of the conjugates and subsequent treatment with beta-glucuronidase allowed identification of the reduced aglycones with authentic samples using gas chromatography-mass spectrometry.

Animals↗
PubMed1985

Accelerated protein turnover in the skeletal muscle of dystrophic mice.

The excretion of 3-methylhistidine increased in the urine of dystrophic mice C57BL/6J. The content of 3-methylhistidine residue decreased in the muscle proteins of dystrophic mice, but not in other organs. Methylated proteins in the skeletal muscle, actin and myosin, were partially purified from the dystrophic and control muscles. The amount of 3-methylhistidine residue in unit weight of the actin and myosin preparations was normal in dystrophic muscle. These three facts indicate that the turnover rates of actin and myosin are increased in the muscle of the dystrophic mice.

Actins↗
PubMed1984

Determination of peptidoaminobenzophenone (2-o-chlorobenzoyl-4-chloro-N-methyl-N'-glycylglycinanilide) and its metabolites in human plasma by capillary gas chromatography negative ion chemical ionization mass spectrometry--2.

The capillary gas chromatographic negative ion chemical ionization mass spectrometric assay of peptidoaminobenzophenone (2-o-chlorobenzoyl-4-chloro-N-methyl-N'-glycylglycinanilide) (1) and its three metabolites in human plasma reported in Part 1 was changed as follows: (1) the reagent gas was changed to ammonia from isobutane; (2) each unlabelled compound (1%) was added to the deuterium-labelled compound used as the internal standard; (3) all samples were injected in the splitless mode; (4) one more metabolite, lormetazepam, was determined; (5) day-to-day reproducibility was checked in the range of 1-50 ng ml-1. Points 1 to 3 improved the preciseness with small-sized samples. Calibration curves were prepared in the range of 0.5-50 ng ml-1. Plasma levels of compound 1 and its four metabolites in 10 volunteers were measured.

Gas Chromatography-Mass Spectrometry↗
PubMed1984

High-performance liquid chromatographic analysis of ammonium in human urine.

A method for the quantitative determination of ammonium in human urine by high-performance liquid chromatography (HPLC) is described. After making fluorescent substances with fluorescamine, they were separated and quantified by their fluorometric intensity. The intensity (as measured by peak height) was linear between 0.5 and 5.0 micrograms, and coefficients of variation for elution time and peak height on replicate analysis of the standard were 0.15 and 4.2%, respectively. Recoveries of added ammonium were 96.5 and 97.3%, respectively, on 2.0 and 3.0 micrograms by this method. Detection limit of this method was 0.2 microgram. There was good agreement between the proposed HPLC method (X) and ion chromatographic method (Y), giving the relationships as Y = 0.956X + 0.012, r = 0.991.

Adult↗