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Biomedical subjects

H Ono

Publications and source records attributed to H Ono.

At least 523 records · Page 29Linked to original sources
PubMed1987

Pharmacological properties of the novel non-steroidal antiinflammatory agent N-methoxy-3-(3,5-di-tert-butyl-4-hydroxybenzylidene)pyrrolidin-2 -one.

The antiinflammatory activity of the novel pyrrolidin-2-one derivative N-methoxy-3-(3,5-di-tert-butyl-4-hydroxybenzylidene)pyrrolidin-2-o ne (E-5110) was investigated and compared with those of indomethacin and piroxicam in various antiinflammatory, analgesic and antipyretic animal models. The acute antiinflammatory activity of E-5110 on the carrageenin paw edema was similar to that of indomethacin, and half that of piroxicam. The chronic inflammatory responses in established adjuvant- and type II collagen-induced arthritis, which are widely used models of rheumatoid arthritis, were suppressed as effectively by E-5110 as by indomethacin and piroxicam. E-5110 decreased the pleural exudate volume and inhibited leucocyte infiltration in a reversed passive Arthus reaction more potently than indomethacin, suggesting that mediators other than prostaglandin E2 may play an important role in this inflammatory process. The analgesic potency of E-5110 against inflammatory pain was similar to that of indomethacin or piroxicam, but the antipyretic activity of E-5110 was more potent than that of the reference drugs. The ulcerogenic effect of E-5110 on rat gastric mucosa was less than those of indomethacin and piroxicam. In conclusion, E-5110 is a very potent antiinflammatory compound acting against various types of inflammation, and has a favorable therapeutic index.

Animals↗
PubMed1987

Simultaneous evaluation of drug effects on both the spinal cord and the descending pathways in rats.

Effects of drugs affecting the central nervous system on the spinal reflexes and the descending modulations of the reflexes were simultaneously evaluated in rats. Mono- and polysynaptic reflexes were, respectively, increased and decreased by conditioning stimulation of the nucleus raphe in the medulla, with a deflection in resting dorsal root potential being evoked by the stimulation. Baclofen exclusively depressed the segmental responses without affecting the descending modulatory systems. On the other hand, KW-6629 (7-chloro-N,N,3-trimethylbenzo[b]furan-2-carboxamide) significantly depressed the descending modulations without affecting the segmental responses which were sensitive to baclofen. Diazepam and suriclone reduced the descending influence without affecting the ventral root reflexes. Tolperisone and chlorphenesin carbamate as well as tizanidine depressed not only the segmental reflexes but also the descending modulations. Thus, sites of drug actions were estimated.

Animals↗
PubMed1986

[The level of the musical loud sound and noise induced hearing impairment].

Recently, there has been an increasing number of reports concerning hearing impairment which musical loud sound is thought to be one of the causes. We are getting more of this musical loud sound as cassette tape recorders with head phones such as Walkman and so forth get popular as well as occasions to attending rock concerts and going to discotheques increase. This hearing impairment is generally called discotheque deafness and the following three types are considered; 1) deafness which have fixed by accumulation of loud sound over a long period of time as seen in people involved in musical performance such as rock musicians and mixing engineers; 2) abrupt noise induced hearing impairment triggered by loud sound and 3) state of deafness which is a progressing stage towards recovery of noise induced temporary threshold shift (NITTS), which occurs temporarily by a loud sound stimulus, and hearing ability recovers afterward. However, it is considered that these musical loud sounds not only changes every moment according to method of performing or type of music, but the volume of the sound actually reaching the auditory sense differs largely by locations and direction of the ear and speakers. So it becomes necessary to measure the accumulation of the noise which each individual is exposed under over a long period of time and at the same time carry out the regular medical checkups including hearing test to check the initiation and advancement of the noise induced hearing impairment. Then we can examine the relationship between loudness of the environmental noise and initiation and advancement of the hearing impairment. However, there has not been a device which is compact and measures noise exposure individually over a long period of time. So we have experimentally produced ultra compact noise dosimeter which we named Noise Badge, and with it we actually measured individual noise exposure over a long time in rock music, noise in discotheque and noisy factory. Then we examined the relationship between these loud sound and noise induced temporary threshold shift (NITTS) in discotheques and noise proof room using simulation of loud sound exposure. Moreover, we measured the most comfortable loudness level of head phones in each examine and different types of music with environmental noise in consideration, thus examining the relationship between musical loud sound and the hearing impairment.

Adaptation, Physiological↗
PubMed1986

Translocation of proteins into rat liver mitochondria. The precursor polypeptides of a large subunit of succinate dehydrogenase and ornithine aminotransferase and their imports into their own locations of mitochondria.

The precursor polypeptides of a large subunit of succinate dehydrogenase and ornithine aminotransferase (the enzymes which are located in the mitochondrial inner membrane and matrix respectively) were synthesized as a larger molecular mass than their mature subunits, when rat liver RNA was translated in vitro. These precursor polypeptides were also detected in vivo in ascites hepatoma cells (AH-130 cells). When the 35S-labeled precursor polypeptides were incubated with isolated rat liver mitochondria at 30 degrees C in the presence of an energy-generating system, these two precursors were converted to their mature size and the 35S-labeled mature-size polypeptides associated with mitochondria. Furthermore, these mature-size polypeptides were recovered from their own locations, the inner mitochondrial membrane and the matrix. The precursor of ornithine aminotransferase incubated with rat liver mitochondria at 0 degree C was specifically and tightly bound to the surface of the mitochondria even in the presence of an uncoupler of oxidative phosphorylation. This precursor, bound to the mitochondria, was imported into the matrix when the mitochondria were reisolated and incubated at 30 degrees C in the presence of an energy-generating system, suggesting that a specific receptor may be involved in the binding of the precursor. The processing enzyme for both precursor polypeptides seemed to be located in the mitochondrial matrix and was partially purified from the mitochondria. A metal-chelating agent strongly inhibited the processing enzyme and the inhibition was recovered by the addition of Mn2+ or Co2+.

Animals↗
PubMed1986

Different effects of noradrenaline, angiotensin II and BAY K 8644 on the abolition of autoregulation of renal blood flow by verapamil.

To examine the role of Ca channels in autoregulation of renal blood flow in response to changes of perfusion pressure, experiments were performed with perfused kidney in anesthetized dogs using a Ca channel activator, BAY K 8644, and vasoconstrictors such as noradrenaline and angiotensin II. Control observations usually showed excellent autoregulation of renal blood flow at pressures between 120 and 200 mm Hg, the autoregulatory index being less than 0.2. Verapamil (50 micrograms/min, i.a. infusion) obviously inhibited the renal autoregulation. Simultaneous infusion of 5 micrograms/min of BAY K 8644 with verapamil prevented both the increase of renal blood flow and the impairment of the autoregulation caused by verapamil. Whereas simultaneous infusion of noradrenaline (1 and 3 micrograms/min) or angiotensin II (0.1 and 0.3 micrograms/min) with verapamil dose-dependently reduced renal blood flow, these drugs could not antagonize the inhibitory effect of verapamil on autoregulation. The present experiments show that Ca channels play an important role in establishing renal autoregulation, and that a mere vasoconstriction by noradrenaline and angiotensin II is distinguished from autoregulatory performance.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1986

The rhino-optical phenomenon: ocular parallax and the visible field beyond the nose.

One of the consequences of the noncoincidence of the nodal point and the center of rotation of the eye is the disappearance of targets near the limit of the nasal visual field when the monocular gaze is directed towards them. This ocular parallax phenomenon, which we measured in six adult subjects, is discussed in terms of its usefulness in demonstrating ocular parallax in a classroom situation. Also, a possible laboratory exercise is suggested.

Distance Perception↗
PubMed1986

Mechanism of synthesis and localization of mitochondrial and cytosolic fumarases in rat liver.

Fumarases in the mitochondrial and cytosolic fractions of rat liver were separately purified and crystallized. These two fumarases were not distinguishable in physicochemical, catalytic, or immunochemical properties. The sequences of seven amino acids in the C-terminal portions of the two fumarases were shown using carboxypeptidase P to be identical, i.e.-Val-Asp-Glu-Thr-Ala-Leu-Lys-. The amino acid sequence of the N-terminal portion of the mitochondrial fumarase was determined by the Edman method as Ala-Gln-Gln-Asn-Phe-Glu-Ile-Pro-Asp-, but that of the cytosolic fumarase could not be determined by the Edman method, since the N-terminal amino acid was blocked. The N-terminal amino acid of the cytosolic fumarase was identified as N-acetyl-alanine by analysis of the acidic amino acid produced by digestion of the enzyme protein with pronase E, carboxypeptidase A and B. Then the sequence of five amino acids in the N-terminal portion was determined by analyzing the acidic peptide obtained by limited proteolysis of the enzyme protein with carboxypeptidase A as Ac-Ala-Ser-Gln-Asn-Ser-. Peptide mapping of the tryptic peptides obtained from the mitochondrial and cytosolic fumarases showed no difference in the amino acid sequences of the two except in their N-terminal portions. The turnover rates of the mitochondrial and cytosolic fumarases were determined by injecting L-[U-14C]leucine into rat and following the decay of specific radioactivity incorporated into immunoprecipitates from the partially purified enzyme. The half-life of the cytosolic fumarase was estimated as 4.8 days from the decay curve of its specific radioactivity. The decay curve of the specific radioactivity of the mitochondrial fumarase, obtained after a single injection of L-[U-14]leucine, was quite unusual: its specific radioactivity remained constant for about 7 days after pulse labeling, and then decreased exponentially with a half-life of 9.7 days. Similar amounts of cytosolic and mitochondrial fumarase were found in the livers of the rat, mouse, rabbit, dog, chicken, snake, frog, and carp, respectively. Similar subcellular distributions of the enzyme were also found in the kidney, heart, and skeletal muscle of rats, and in hepatoma cells (AH-109A). However, in rat brain no fumarase activity was detected in the cytosolic fraction. Two putative precursor polypeptides of rat liver fumarase were synthesized when rat liver RNA was translated in vitro in a rabbit reticulocyte lysate system.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1986

Cadmium stimulates glucose metabolism in rat adipocytes.

Cd2+ caused an increase in CO2 formation from glucose in rat adipocytes. The apparent Km value for glucose was 2.02 mM for control condition, with Cd2+, and with insulin. Cd2+ stimulates glucose metabolism even though specific diffusion of glucose is blocked. A possible site effected by Cd2+ is discussed.

Adipose Tissue↗
PubMed1986

Effects of tizanidine, a centrally acting muscle relaxant, on motor systems.

Effects of tizanidine were studied with special reference to the effect on motor systems. The drug effectively reduced the intercollicular decerebrate rigidity and gamma-activity indirectly recorded from muscle spindle afferent discharges without showing the direct inhibitory effect on muscle spindles in rats. The drug dose-dependently inhibited the phasic responses of alpha-rigidity in anemic decerebrate rats without showing marked inhibition of the tonic response. Tizanidine effectively depressed the crossed extensor reflex in chicks and depressed mono- and polysynaptic reflex potentials in rats; dorsal root reflex was increased transiently. Tizanidine had no effect on the neuromuscular junction in rats and [3H]diazepam binding in rat brain membrane. It is suggested that the depression by tizanidine of gamma-system and spinal reflexes contribute to muscle relaxation and anti-spastic effects and that mechanisms of action are different from those of other centrally acting muscle relaxants such as mephenesin and benzodiazepines.

Animals↗
PubMed1986

Brain stem involvement in the effects of chlorpromazine on the monosynaptic reflex of the rat lumbar spinal cord.

The brain stem areas involved in the inhibitory effect of chlorpromazine (CPZ) on the monosynaptic reflex (MSR) in the lumbar spinal cord of rats were investigated following brain stem transection and focal thermo-lesioning. Transection of the medulla oblongata markedly reduced the effect of CPZ, while transection in the mid-brain or more anterior level did not alter the effect of CPZ. With regard to focal lesions at various sites of the brain stem, lesioning of the medial portion of the medulla oblongata most effectively attenuated the MSR inhibition by CPZ and also attenuated the MSR inhibition induced by phenoxybenzamine. Bilateral lesioning of the locus coeruleus did not attenuate the MSR inhibition by CPZ. These results suggest that the pathway involved in the inhibitory effect of CPZ on the MSR originates in the pons and passes through the medial portion of the medulla oblongata, and that the coerulo-spinal pathway is not the major pathway involved in the effect of CPZ.

Animals↗
PubMed1986

Depth perception as a function of motion parallax and absolute-distance information.

The results of three experiments demonstrated that the visual system calibrates motion parallax according to absolute-distance information in processing depth. The parallax was created by yoking the relative movement of random dots displayed on a cathode-ray tube to the movements of the head. In Experiment 1, at viewing distances of 40 cm and 80 cm, observers reported the apparent depth produced by motion parallax equivalent to a binocular disparity of 0.47 degree. The mean apparent depth at 80 cm was 2.6 times larger than at 40 cm. In Experiment 2, again at viewing distances of 40 cm and 80 cm, observers adjusted the extent of parallax so that the apparent depth was 7.0 cm. The mean extent of parallax at 80 cm was 31% of that at 40 cm. In Experiment 3, distances ranged from 40 cm to 320 cm, and a wide range of parallax was used. As distance and parallax increased, the perception of a rigid three-dimensional surface was accompanied by rocking motion; perception of depth was replaced by perception of motion in some trials at 320 cm. Moreover, the mean apparent depths were proportional to the viewing distance at 40 cm and 80 cm but not at 160 cm and 320 cm.

Cues↗
PubMed1986

Different effects of various vasodilators on autoregulation of renal blood flow in anesthetized dogs.

In order to examine whether the autoregulation of renal blood flow is equally influenced by all kinds of vasodilators, kidney perfusion experiments were performed in anesthetized dogs. The perfused kidney usually showed excellent autoregulation of blood flow over the perfusion pressure between 120 and 200 mmHg. Renal blood flow was increased by the renal arterial infusion of diltiazem (100 micrograms/min), papaverine (10 mg/min) or nicorandil (300 micrograms/min) (at the basal perfusion pressure of 100 mmHg) and was maintained at an increased level while the infusion was continued. On the other hand, renal blood flow was increased only transiently by the infusion of nitroglycerin (50 micrograms/min), and the blood flow gradually decreased to the basal level in spite of the continuous infusion. Infusions of diltiazem and papaverine abolished the autoregulation of renal blood flow besides the vasodilator effect, but infusions of nitroglycerin and nicorandil have no effect on the autoregulation. Furthermore, sodium nitroprusside (30 micrograms/min) and sodium nitrite (5 mg/min), which are assumed to produce vasodilation through cyclic GMP, also have no effect on the autoregulation of renal blood flow. In conclusion, all the vasodilators do not influence the renal blood flow autoregulation, and vasodilation caused by cyclic GMP is unconnected with the myogenic mechanism regulating the renal blood flow.

Animals↗