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Biomedical subjects

R Amano

Publications and source records attributed to R Amano.

At least 19 recordsLinked to original sources
PubMed2001

Inhibitory effect of histamine on axonal transport in cultured mouse dorsal root ganglion neurons.

Histamine is important in mediating peripheral sensory information such as inflammation, allergic hypersensitivity, and itch. In the present study, using video-enhanced microscopy, we investigated the effect of histamine on axonal transport in cultured dorsal root ganglion (DRG) neurons of the mouse. Application of histamine (100 microM) reversibly reduced the number of particles transported within neurites in both anterograde and retrograde directions. The histamine H(1)-receptor agonist 2-thiazolylethylamine (100 microM) and the H(3)-receptor agonist R-alpha-methylhistamine (100 microM) also reduced anterograde and retrograde axonal transport, whereas the histamine H(2)-receptor agonist dimaprit (100-1000 microM) had no effect. The effect of histamine was partially blocked by pretreatment with H(1)-receptor antagonist pyrilamine (1 microM) or the H(3)-receptor antagonist thioperamide (1 microM). Pretreatment with a combination of pyrilamine (1 microM) and thioperamide (1 microM) completely blocked the response to histamine. The H(2)-receptor antagonist cimetidine (1 microM) was ineffective. These results suggest that histamine inhibits axonal transport of cultured mouse DRG neurons via the activation of H(1)- and H(3)-receptors.

Animals↗
PubMed1996

Bone uptake of vanadium in mice: simultaneous tracing of V, Se, Sr, Y, Zr, Ru and Rh using a radioactive multitracer.

The radioactive multitracer technique, which enables simultaneous tracing of a number of elements in a variety of bio-systems and an accurate comparison of their biobehavior, was employed in a study on uptake behavior of trace elements in various mice tissues, focusing on uptake of V by bone. We found that the bone uptake behavior of trace V closely resembles that of trace Sr and Y. It is suggested that V is a bone-seeking element which probably plays an important role in bone formation. The multitracer technique was thus shown to be useful for comparative studies of behavior of trace elements in living organisms.

Animals↗
PubMed1995

Monozygotic twin patients with congenital ichthyosis, microcephalus, spastic quadriplegia, myoclonus, and EEG abnormalities.

A pair of monozygotic twins manifested widespread ichthyosis on the trunk and extremities, mainly on the extensor surface of the lower legs. Both patients had severe developmental retardation, microcephalus, spastic quadriplegia, myoclonus, and hearing impairment. Cranial computed tomography and magnetic resonance imaging revealed diffuse cortical atrophy. Electroencephalography documented diffuse slow wave dysrhythmia and marked epileptic discharges, namely bilateral occipital dominant, and low-voltage multifocal spikes which appeared asynchronously as a burst, mainly during sleep. Skin biopsy revealed hyperkeratosis with parakeratosis. Granular cell layer was not thickened and diminished. Papillomatosis was absent. Electron microscopy did not reveal any distinctive abnormalities. Sjögren-Larsson syndrome and other known ichthyosis syndromes were excluded because of the difference in localization of skin lesions, skin manifestations, lack of papillomatosis, the nature and severity of neurologic symptoms and marked electroencephalographic abnormalities.

Diseases in Twins↗
PubMed1993

Myoclonus epilepsy with ragged-red fibers: a clinical and electrophysiologic follow-up study on two sibling cases.

We performed a 5-year clinical and electrophysiologic follow-up study on two sibling cases with myoclonus epilepsy with ragged-red fibers. Both had myoclonus, intention tremor, slight muscle weakness, slight mental disturbance, hearing impairment, and optic atrophy. Neither had epileptic attacks or truncal or gait ataxia. Biochemical activity of cytochrome c oxidase was at the lower limit of the normal range of values, and an adenine to guanine transition mutation at nucleotide 8344 in the transfer RNA specific for lysine of mitochondrial DNA was detected in both cases. The electroencephalograms showed slowing of basic patterns, diffuse spike-and-wave complexes, occipital dominant wave-and-spike phantoms, 6- and 14-Hz positive spikes, and photosensitivity. No definite deterioration of basic patterns was seen, and diffuse spike-and-wave complexes and photosensitivity gradually disappeared during the slowly progressive clinical course. P2 latencies of pattern-reversal visual evoked potentials throughout the clinical course and III through V interpeak latencies of auditory brainstem responses at follow-up were prolonged without giant sensory evoked potentials in both cases.

Adolescent↗
PubMed1992

Dipole tracing in childhood epilepsy with special reference to rolandic epilepsy.

To assess the clinical applicability of dipole tracing in childhood epilepsy, the location and stability of electric source generator of focal spikes seen in EEG of epileptic children were investigated using this method. The patients were divided into 3 groups; benign childhood epilepsy with centrotemporal spikes (BCECS, Group A, n = 14), other types of epilepsy with centrotemporal spikes (Group B, n = 15) and epilepsy with focal spikes in other areas (Group C, n = 13). The spike dipole in each group was analyzed using dipole tracing method. The following results were obtained. (1) The spikes of BCECS were characterized by constantly stable dipoles, compared to those of the other types of childhood epilepsy. The spikes of epileptic children with mental retardation mostly lacked the stability of dipoles. These seemed to suggest that the stability of dipoles was closely related to the prognosis and pathophysiology of epilepsy. (2) The dipoles of BCECS were localized strictly in the Rolandic area. Dipole tracing from EEG spikes was considered to contribute to the elucidation of the pathophysiology of childhood epilepsy.

Adolescent↗
PubMed1990

Bilateral intrahepatic lithiasis without extrahepatic bile duct stones.

Bilateral intrahepatic lithiasis is a rare condition, and for this reason a nationwide survey was conducted. Reports on 675 patients with bilateral intrahepatic lithiasis over a 10-year-period were collected. Among these, 258 patients with bilateral intrahepatic lithiasis having no extrahepatic bile duct stones were analyzed. The peak incidence was seen in the fourth to sixth decades. Males and females were equally effected. The stones removed were mainly calcium bilirubinate stones (75.6%). The main clinical symptoms were abdominal pain, fever and jaundice. Charcot's triad was seen in 29.7%, while 12.4% of the patients had no symptoms. Visualization of each segmental duct of the liver by direct cholangiography was excellent in this survey and ranged from 88 to 97.3% of the patients. The most frequent site of stones was the left hepatic duct (60.1%). The site of bile duct dilatation coincided with the location of stones. The most common sites of stenosis were the central part of the lateral segmental duct (32.5%) and the left hepatic duct (37.6%). Hepatic resection was employed in 49.2% of the patients, and drainage procedures were added in 95.6%. Follow-up studies of 236 patients treated by surgery revealed good results in 67.4%, fair in 13.6%, and poor in 7.6%. In these patients, however, endoscopic lithotomy was often employed intra- and/or post-operatively. Conducting hepatic resection, with adequate biliary drainage procedure and cholangiofiberscopic lithotomy may help to improve the therapeutic results of bilateral intrahepatic lithiasis.

Adult↗
PubMed1990

Long-term prognosis of the Lennox-Gastaut syndrome.

A long-term follow-up study of 89 patients of Lennox-Gastaut syndrome (LGS) disclosed the persistent occurrence of seizures in 68 patients (76.4%) and severe mental defect in 48 (53.9%). An analysis of the correlation between the mental and seizure prognoses confirmed that the persistence of minor seizures could result in mental deterioration. An examination of the evolutional changes in EEG demonstrated that diffuse slow spike-waves characteristic of LGS gradually disappeared, while focal epileptic discharges, especially multifocal spikes, appeared in spite of the persistence of minor seizures. The diagnostic criteria were satisfied in only 31 (47.0%) of 66 patients with the persistence of minor seizures. Patients with multiple independent spike foci and minor seizures were considered to belong to a specific type of epilepsy, namely the severe epilepsy with multiple independent spike foci (the severe epilepsy with MISF). The seizure and mental prognoses were poorer in patients who evolved into the severe epilepsy with MISF than others.

Adolescent↗
PubMed1988

Rational treatment of refractory epilepsy in childhood.

A multifaceted study on childhood refractory epilepsy disclosed an insufficient classification of epilepsies and epileptic seizures, and inappropriate polypharmacy as the most important factors preventing appropriate therapy. By means of an adjustment of AEDs based on the accurate classification of epilepsies and epileptic seizures, the number of AEDs could be reduced in 37.5% and monotherapy was successful in 13.8% of refractory cases. Most of the latter were those of partial epilepsy and generalized epilepsy with the monoseizure type. The exacerbation of seizures due to AEDs was also mentioned as one of the important side effects of AEDs.

Adolescent↗
PubMed1986

Thallium-201 radioactive implant induced X-ray emission scanning of stable iodine distribution in thyroid--phantom experiment.

A new method has been developed for imaging the thyroid gland by the use of 201Tl radioactive implant induced X-ray emission (RIXE). The thyroid phantom was made from two cylindrical tubes embedded in plastic neck phantom. Each tube consisted of stable iodine and 201Tl radioactive source in 10 ml water solution. Some photopeaks in the energy range from 20 to 200 ke V were scanned along a horizontal axis by the collimated Ge detector with high energy resolution. The distribution on the horizontal axis was obtained for the generated I K alpha-ray and some primary 201Tl radiations. The 201Tl RIXE scanning can provide information about the distribution of iodine with 201Tl as well as 201Tl distribution in the thyroid gland. The effectiveness of the 201Tl RIXE technique as a thyroid scanning method is discussed.

Iodine↗
PubMed1986

[Clinical evaluation of a new tumor marker, CA 15-3, in breast cancer; a comparative study with CEA].

Recently, a new RIA method has been developed by Centocor Co., utilizing the monoclonal antibody CA 15-3. We performed a clinical trial to evaluate its utility as a tumor marker for breast cancer in comparison with CEA. We set 15 U/ml as the cut-off value of serum CA 15-3 level from results acquired from controls; 10 volunteers and 17 patients with non-malignant diseases. The CA 15-3 positive rate among the cases of primary breast cancer was 13.3%, which was of poor diagnostic value. In the recurrent cases the positive rate of CA 15-3 was 72.0%, which was valuable compared with that of serum CEA, 52.0%. In the cases of primary cancers other than breast cancer, the positive rate of CA 15-3 was 6.9%.

Adult↗
PubMed1985

[A case of remission of metastatic gastric cancer lesions in the chest and abdominal wall by 5'-DFUR administration].

52-year-old female was weakened and bed-ridden by metastasis of gastric cancer to the chest and abdominal wall, and peritonitis carcinomatosa 2 years after gastrectomy. One week after administration of 5'-DFUR, 1200 mg/d, p.o., a clinical effect was seen. In 3 weeks metastatic lesions had diminished in size, ascites had decreased and the patient had regained her appetite and put on weight. She recovered sufficiently to be able to do some daily work. Pathological degeneration and necrosis of cancer cells were observed. Although she died 8 months after remission, 5'-DFUR was effective in improving her condition and prolonging her life.

Abdominal Muscles↗
PubMed1984

Radioactive implant induced x-ray emission technique for noninvasive determination of iodine content in thyroid: experimental study.

A new technique, radioactive implant x-ray emission spectrometry to determine the in vivo iodine content of the human thyroid is proposed. The variations of counting rate and effective excitation efficiencies of I K alpha (28.6 keV) with iodine content, thyroid volume and skin-thyroid distance were studied for the 201Tl source to examine the properties of excitation and photon attenuation. As a result, the gland depth and volume could be estimated from the peak ratios of 30.7 keV/167.6 keV and 28.6 keV/167.6 keV. Using a 1 MBq 201Tl implant source, the detectable minimum iodine concentration found was approximately 70 micrograms/g for 2000 s measuring time in the phantom experiment. The effectiveness of the RIXE technique is discussed. It was concluded that the 201Tl RIXE spectrometry might serve to determine the in vivo iodine content of the human thyroid.

Americium↗
PubMed1982

[Clinical study of preoperative chemotherapy of primary breast cancer. 1. Efficacy of a combined use of CPA (endoxan) and FT-207 (or 5-FU dry syrup)].

In twenty-nine cases of primary breast cancer preoperative treatment using CPA and FT-207 (or 5-FUDS) was performed to determine their efficacy. Daily dose of each anticancer drugs was as follows: CPA 50-200 mg, FT-207 200-600 mg, 5-FUDS 200 mg, p.o.. The total doses were CPA 1.8 g, FT-207 5.0g, 5-FUDS 3.4 g in average. In 11 cases (37.9%) reduction in tumor size was obtained. According to Ohboshi's criteria, over Grade II a effect was seen in 5 cases (17.2%), while Grade III effect was not seen in any of the cases. Effective cases were more frequently observed among those which received CPA at 25 mg/kg or more, or FT-207 (5-FUDS) at 80 mg/kg or more. Main side effects were G. I tract symptoms such as anorexia and nausea. To obtain definitive conclusion on the clinical significance of use of CPA and FT-207 (5-FUDS) as preoperative chemotherapy for breast cancer, further studies are required.

Adult↗