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Biomedical subjects

O Inanami

Publications and source records attributed to O Inanami.

At least 37 records · Page 2Linked to original sources
PubMed1998

Visualization of the topographical structure of the anesthetized mouse brain by MR microimaging.

A nuclear magnetic resonance (NMR) spectrometer equipped with a magnet producing a high and extremely uniform magnetic field (7.05 T) was combined with a strong field gradient coil (3.5 mT/cm) and applied to MR microimaging of the mouse brain to visualize its topographical structure. Since the proton-density-weighted condition (long repetition time (TR) and short echo time (TE); TR/TE = 3,000 ms/10.4 ms) was found to be the most suitable for imaging the mouse brain, mid-sagittal and coronal sections in 1-mm- or 0.3-mm-thick slices were imaged according to the multislice spin echo sequence with 2 or 8 acquisitions, a 2 kHz pulse width and a 256 x 256 data matrix. As expected, the resolution of MR microimaging was comparable to that of the histological sections. The white matter especially, could be distinguished from the gray matter in some regions of the brain. Coronal sections of the brain also showed that the hippocampal CA1-CA3 regions were distinguishable from the other regions. The results suggested that the present MR microimaging technique might be a useful tool for the study of topological anatomy and submicroscopic research using brains of small laboratory animals.

Animals↗
PubMed1996

Inhibition of collagen-induced platelet aggregation in Japanese black cattle with inherited platelet disorder, Chediak-Higashi syndrome.

Aggregation properties of platelets were examined in Japanese Black cattle with Chediak-Higashi syndrome (CHS) and normal control cattle. Platelet aggregation induced by collagen was decreased in platelets of the cattle with CHS, but not ADP (10-20 microM), thrombin (0.5-1.0 U/ml) and phorbol-12-myristate 13-acetate (PMA, 3.2 microM). The aggregation response induced by collagen in CHS platelets lacks the change in shape which usually occurs in normal platelets. Simultaneous stimulation by collagen (10 micrograms/ml) + ADP (10 microM) is effective in restoring collagen-induced aggregating response in CHS platelet, although pretreatment of ADP (10 microM) could not restore the collagen (10 micrograms/ml)-induced aggregating response, suggesting that there is a certain threshold of stimulation intensity above which collagen-induced aggregation of CHS platelet can begin. Control normal platelets, previously exposed to ADP (10 microM) and collagen (10 micrograms/ml), showed no further response to exposure to a third aggregating agent (arachidonic acid, 5 mM). On the other hand, the final agent was able to elicit aggregating responses in CHS platelets, suggesting that the arachidonate aggregating system may be suppressed in CHS cattle, but fully activated in control animals. Furthermore, normal platelets showed a significant decrease in aggregating response to collagen when pretreated with a cyclooxygenase inhibitor, indomethacin (10(-5) M), whereas CHS platelet was insensitive to indomethacin. This indomethacin-treated normal platelet mimicked the CHS collagen-induced aggregation pattern. These data suggest that a signal transduction process from receptor-operated events to arachidonate metabolism is suppressed in collagen-induced CHS platelet aggregation.

Adenosine Diphosphate↗
PubMed1996

Lipid peroxide levels and superoxide-scavenging abilities of Sera obtained from hotbred (Thoroughbred) horses.

Hotbred (Thoroughbred) horses were grouped into three classes according to the levels of constant physical exercise (foals, 6 months old; racing horses, 5 years old; horses for breeding, 6-10 years old), and lipid peroxide levels in their sera were measured as thiobarbituric acid-reactive substances. No significant differences were observed among them. The superoxide-scavenging abilities of sera were measured next; to examine the antioxidative properties of hotbreds, and were found to be highest in the racing horses. The higher scavenging ability of the racing horses might contribute to keep their lipid peroxide levels as low as those of the other two groups. HPLC analysis of substances in sera suggested that the presence of albumin-bound bilirubin was one of the reasons for the high superoxide-scavenging ability of sera of the racing horses. When the hotbreds were compared with coldbred (crossbred) horses, the lipid peroxide levels of hotbreds was higher (7.0 +/- 1.2 nmol/ml) than that of coldbreds (2.6 +/- 0.7 nmol/ml). Comparison of the superoxide-scavenging abilities of sera between hotbreds and coldbreds showed that the hotbreds possessed higher scavenging ability than the coldbreds. These results indicated that the lipid peroxide level in sera of hotbreds was higher than that of coldbreds regardless of the higher superoxide-scavenging abilities of sera.

Animals↗
PubMed1996

Oral administration of bovine lactoferrin for treatment of intractable stomatitis in feline immunodeficiency virus (FIV)-positive and FIV-negative cats.

OBJECTIVE: To study the effects of oral administration of bovine lactoferrin (LF) on intractable stomatitis in feline immunodeficiency virus (FIV)-positive and FIV-negative cats, and phagocytosis of neutrophils in healthy and ill cats, simultaneously. ANIMALS: 7 ill cats with diagnosis of intractable stomatitis (4 FIV positive and 3 FIV negative) and 7 healthy, FIV-negative cats. PROCEDURE: LF (40 mg/kg ot body weight) was applied topically to the oral mucosa of cats with intractable stomatitis daily for 14 days and improvement of clinical signs of disease (pain-related response, salivation, appetite, and oral inflammation), expressed by scoring from 1 to 4, were evaluated. Assay of neutrophil phagocytosis was examined before and 2 weeks after starting LF treatment, using nonopsonized hydrophilic polymer particles (2 microns). RESULTS: Oral administration of LF improved intractable stomatitis in all 4 respects. Phagocytic activity of neutrophils increased after LF treatment. This effect was observed in healthy and ill (FIV positive and FIV negative) cats. CONCLUSION AND CLINICAL RELEVANCE: Oral administration of LF improved intractable stomatitis and concurrently enhanced the host defense system. Topical application of LF to oral mucous membrane is useful as a treatment for intractable stomatitis even in FIV-positive cats.

Administration, Oral↗
PubMed1995

The suppression of age-related accumulation of lipid peroxides in rat brain by administration of Rooibos tea (Aspalathus linearis).

The protective effects of Rooibos tea (RT), Aspalathus linearis, against damage to the central nervous system (CNS) accompanying aging were examined by both the thiobarbituric acid reaction (TBA) and magnetic resonance imaging (MRI) methods in brains of chronically RT-treated rats. Ad libitum administration of RT was begun with 3-month-old Wistar female rats and continued for 21 months. The contents of TBA reactive substances (TBARS) in the frontal cortex, occipital cortex, hippocampus and cerebellum in 24-month-old rats after administration with water were significantly higher than those in young rats (5 weeks old). However, no significant increase of TBARS was observed in RT-administered aged rats. When MR images of the brains of 24-month-old rats with and without RT as well as 5-week-old rats were taken, a decrease of the signal intensity was observed in the cerebral cortex, hippocampus and cerebellum in MR images of aged rats without RT, whereas little change of the signal intensity was observed in MR images of the same regions of 24-month-old rats treated with RT, whose images were similar to those of young rats. These observations suggested that (1) the age-related accumulation of lipid peroxides in the brain was closely related to the morphological changes observed by MRI, and (2) chronic RT-administration prevented age-related accumulation of lipid peroxides in several regions of rat brain.

Administration, Oral↗
PubMed1995

alpha-Phenyl N-tert-butyl nitrone (PBN) increases the cortical cerebral blood flow by inhibiting the breakdown of nitric oxide in anesthetized rats.

The effects of intravenous administration of alpha-phenyl N-tert-butyl nitrone (PBN) on cortical cerebral blood flow (CBF) were examined in Wistar rats under pentobarbital anesthesia and artificial ventilation. The cortical CBF in parietal cortex was measured by laser Doppler flowmetry. Intravenous administrations of 2 mg/kg and 20 mg/kg of PBN dose-dependently produced significant increases in cortical CBF and decreases in systemic blood pressure (BP). To examine whether these increased responses in cortical CBF produced by PBN were associated with the vasodilatation system of nitric oxide (NO), the NO synthase inhibitor L-NG-nitroarginine (L-NOArg), which is an analog of L-arginine, was used to inhibit the NO-related-vasodilatative system. Since the PBN-induced responses in the cortical CBF were much attenuated in L-NOArg-treated rats (30 mg/kg, i.v.), it was inferred that NO-related vasodilatation was strongly associated with the PBN-induced increase in cortical CBF.

Amino Acid Oxidoreductases↗
PubMed1994

Magnetic resonance imaging of young and aged rat brains under a magnetic field of 7.05 T.

Using a homemade MR imaging probe (Helmoholtz coil), MR images of brains of 5-week-old and 23- or 24-month-old Wistar rats were taken under a magnetic field of 7.05 T (Tesla). The probe was designed to fit the rat head and made by winding thin copper film round an acrylic tube with a 5-cm i.d., 10-cm length and 2-mm thickness. This was adjusted to resonate with the 300 MHz radiofrequency corresponding to the resonance frequency of 1H under a magnetic field of 7.05 T. MR images were obtained by T1-weighted and two-dimensional Fourier transformation techniques. The sagittal and coronal sections were imaged in 1-mm-thick slices. The size of the data matrix was 128 phase-encoded steps. Each image was obtained through eight acquisitions. A comparison of the MR images with those semi-microscopically taken at the same position of the coronal section revealed that the cerebral cortex, hippocampus, hypothalamus and thalamus were clearly imaged by this probe. With aging, MR images of cerebral cortices were observed with decreased signal intensities. Enlargement of the third ventricles and hypertrophy of cranical parietal bones were also recognized in sagittal MR images of aged rats. These observations were more marked in males than in females. From these observations it was concluded that this probe was applicable for MR imaging of rat brains under a magnetic field of 7.05 T.

Aging↗
PubMed1992

Responses of regional cerebral blood flow to intravenous administration of thyrotropin releasing hormone in aged rats.

The effects of i.v. administration of thyrotropin releasing hormone (TRH) on regional cerebral blood flow (rCBF) were examined in both healthy adult (3-5 months old) and healthy aged (24-25 months old) male Wistar rats under halothane anesthesia. The rCBFs in 9 different brain regions-cerebral cortex, caudate putamen, hippocampus, thalamus + hypothalamus, superior colliculus, inferior colliculus, cerebellum, pons, and medulla-were measured by [14C]iodoantipyrine method. In the adult rats, i.v. administration of TRH (300 micrograms/kg) produced significant increases in rCBFs in cerebral cortex, caudate putamen, hippocampus, thalamus + hypothalamus and superior colliculus. In the aged rats, the rCBFs in all brain regions measured did not change significantly by TRH administration. From these results, it is suggested that the system involved in TRH-induced vasodilatation of cerebral blood vessels was impaired with aging.

Aging↗
PubMed1992

Nitric oxide (NO) is involved in increased cerebral cortical blood flow following stimulation of the nucleus basalis of Meynert in anesthetized rats.

The effects of i.v. administration of a nitric oxide (NO) synthase inhibitor, L-NG-nitroarginine (L-NOArg), on the increase in cerebral cortical blood flow (cortical BF), following either electrical stimulation of the nucleus basalis of Meynert (NBM), whose cholinergic fibers project to the cortex, or hypercapnia with 10% CO2 inhalation, were studied in anesthetized rats. Cortical BF was measured using laser Doppler flowmetry. The threshold intensity of electrical stimulation of the NBM (0.5 ms, 50 Hz for 10 s) that induced an increase in regional cortical BF was defined as 1T. The cortical BF was increased on a stimulus intensity dependent manner at 1T-5T intensities tested. L-NOArg was administered cumulatively i.v. starting from 0.3 mg/kg, then 3 mg/kg, and 30 mg/kg. Time interval between each cumulative administration of L-NOArg was approximately 40 min. Three and 30 mg/kg of L-NOArg significant reduced the NBM stimulation-induced increase of cortical BF at intensities of 2T and 3T. The response at an intensity of 5T was reduced only by 30 mg/kg of L-NOArg to about half the control response. The reduced responses at 2T, 3T, and 5T were reversed following the i.v. administration of a physiological precursor of NO, L-arg (300 mg/kg). Inhalation of 10% CO2 for 15 s induced an increase in cortical BF which was not influenced by L-NOArg and L-Arg. These results suggest that NO is a necessary factor in the vasodilation of the cortical BF that is brought about by cholinergic fibers originating in the NBM.

Anesthesia↗
PubMed1990

Responses of regional cerebral blood flow following focal electrical stimulation of the nucleus basalis of Meynert and the medial septum using the [14C]iodoantipyrine method in rats.

The effects of focal electrical stimulation of the nucleus basalis of Meynert (NBM) and the medial septum (MS) on regional cerebral blood flow (rCBF) of the 14 brain regions were examined in halothane-anesthetized rats using the [14C]iodoantipyrine ([14C]IAP) method. The stimulation of the unilateral NBM (with parameters of 200 microA, 0.5 ms, 50 Hz for 60 s) produced significant increases in frontal, parietal and occipital cortical blood flows in the hemisphere ipsilateral to the stimulated NBM; no rCBFs in all other brain regions examined were influenced by the stimulation. The stimulation of the MS produced significant increases in bilateral hippocampal rCBFs, but rCBFs in other brain regions were not influenced by the stimulation. In summary, the response of increase in rCBF following focal electrical stimulation of the NBM or MS is restricted to regions that receive cholinergic nerve projections from the NBM or MS.

Animals↗
PubMed1990

Stimulation of the nucleus basalis of Meynert and substantia innominata produces widespread increases in cerebral blood flow in the frontal, parietal and occipital cortices.

The effect of a focal stimulation of the magnocellular nucleus of the basal forebrain at two different areas, the nucleus basalis of Meynert (NBM) and the substantia innominata (SI), on local cerebral blood flow (CBF) in the frontal, parietal and occipital cortices was examined in urethane-anesthetized rats. The stimulation, either electrically or chemically, of both the NBM and SI produced significant CBF increase in all these 3 cortices ipsilateral to the stimulation site. This fact suggests that activation of neurons originating in the NBM and SI produces widespread increases in local CBF in the ipsilateral cerebral cortex.

Animals↗
PubMed1989

Stimulation of the septal complex increases local cerebral blood flow in the hippocampus in anesthetized rats.

The effects of focal stimulation, either electrically or chemically, of the septal complex (i.e. the medial septal nucleus and the nucleus of the diagonal band) on the local hippocampal cerebral blood flow (Hpc CBF) measured by laser Doppler flowmetry were examined in anesthetized rats. Electrical stimulation of the septal complex produced a current-dependent increase in Hpc CBF that was accompanied by an increase in extracellular acetylcholine (ACh) release in the hippocampus. Microinjection of L-glutamate (50-100 nmol) into the septal complex also produced an increase in Hpc CBF. The L-glutamate-induced vasodilative response of Hpc CBF was markedly attenuated after administration of nicotinic cholinergic blocking agent, mecamylamine (2 mg/kg, i.v.). It was suggested that the cholinergic septohippocampal nerve fibers act as an intracerebral vasodilative neural system by releasing ACh from the nerve terminals in the hippocampus and by activating the nicotinic cholinergic receptor.

Anesthesia↗
PubMed1989

Stimulation of the nucleus basalis of Meynert increases cerebral cortical blood flow in rats.

Focal electrical stimulation of the magnocellular nucleus of the basal forebrain (nucleus basalis of Meynert; NBM) or a microinjection of L-glutamate (50 nmol) into the NBM increased cerebral cortical blood flow in the parietal lobe in urethane-anesthetized rats. The vasodilative responses were elicited only ipsilateral to the site of stimulation. Most of the vasodilative responses were abolished by intravenous administrations of muscarinic and nicotinic cholinergic blocking agents (atropine 0.5 mg/kg and mecamylamine 2 mg/kg). This suggests that the cholinergic projecting system sending fibers from the NBM to the parietal lobe contributes to the vasodilation of the cortex by activating muscarinic and nicotinic cholinergic receptors.

Animals↗
PubMed1988

Contribution of cholinergic vasodilators on the increase in cerebral cortical blood flow responses to the intravenous administration of thyrotropin releasing hormone in anesthetized rats.

The effect of an intravenous administration of thyrotropin-releasing hormone (TRH) on the regional cerebral blood flow in the sensory cortex was studied in halothane-anesthetized adult Wistar rats. The regional cerebral blood flow was continuously monitored with the laser Doppler flowmetry. The cerebral blood flow increased dose-dependently following the administration of 3 x 10(2) and 3 x 10(3) microns/kg TRH. The systemic blood pressure also increased simultaneously. After maintaining the systemic blood pressure at a constant level via a pressure reservoir system, the TRH-induced increases in the cerebral blood flow continued to be observed. In atropinized animals, the blood pressure increased as high as that indicated in non-atropinized animals following TRH administration, but the responses of the cerebral blood flow in the latter were much attenuated. It was suggested that the cholinergic vasodilative system contributed to the TRH-induced increase in cerebral blood flow.

Animals↗
PubMed1988

ESR and spin-trapping study of free radicals in gamma-irradiated solid lysozyme.

Free radicals produced by gamma-irradiation of solid lysozyme were investigated by a technique combining ESR, spin-trapping and enzymatic digestion. MNP and DMPO were used as spin-trapping reagents. The solid lysozyme was first gamma-irradiated and then dissolved in an aqueous solution containing the spin-trapping reagent to stabilize free radicals. The spin adducts of lysozyme were digested to oligopeptides to get ESR spectra having a well-resolved hyperfine structure. The ESR spectra obtained showed that carbon-centered radicals, -CH-, at the side chains of amino acids, and thiyl radicals, -CH2-S., at disulfide bridges were produced in gamma-irradiated solid lysozyme.

Electron Spin Resonance Spectroscopy↗
PubMed1987

Spin trapping of precursors of thymine damage in X-irradiated DNA.

A spin-trapping method combined with ESR spectroscopy was utilized to obtain evidence for the presence of precursor radicals leading to damage in X-irradiated DNA. Two technical improvements were introduced to the conventional spin-trapping method to make possible its application to large molecules such as DNA: prior to X irradiation, sonolysis of aqueous DNA solution by 19.5-kHz ultrasound was made to get a highly concentrated DNA solution and to lower the viscosity of the solution; after precursor radicals in X-irradiated DNA were trapped by a spin-trapping reagent, the DNA was digested to oligonucleotides by DNase I to get an ESR spectrum with a well-resolved hyperfine structure. Thus, it was recognized that the ESR spectrum obtained after X irradiation of the aqueous solution containing DNA and the nitroso spin-trapping reagent 2-methyl-2-nitrosopropane consisted of at least three sets of signals in the DNA. Identification of free radicals was made by comparing the spectrum with that of thymidine, which was precisely examined by a spin-trapping method combining two kinds of spin traps (nitroso and nitrone compounds) with liquid chromatography. As a result, all the signals were identified as the spin adducts of radicals produced at the thymine base moiety of DNA. The 5-hydroxy-5,6-dihydrothymin-6-yl radical was identified as a precursor of 5,6-dihydroxy-5,6-dihydrothymine (thymine glycol), the 6-hydroxy-5,6-dihydrothymin-5-yl radical as a precursor of 6-hydroxy-5,6-dihydrothymine, and the 5-methyleneuracil radical as a precursor of 5-(hydroxymethyl) uracil.

DNA↗