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Biomedical subjects

I Taniguchi

Publications and source records attributed to I Taniguchi.

At least 55 records · Page 3Linked to original sources
PubMed1996

Optical imaging of spatiotemporal patterns of glutamatergic excitation and GABAergic inhibition in the guinea-pig auditory cortex in vivo.

1. Glutamatergic excitation and gamma-aminobutyric acid (GABA)-ergic inhibition in layers II and III of the auditory cortex of anaesthetized guinea-pigs were recorded optically using a voltage-sensitive dye RH795 and a 12 x 12 photodiode array. 2. After contralateral ear stimulation with pure tones, transient excitatory responses followed by inhibitory responses were observed in fields A (primary) and DC of the auditory cortex. The area of the excitatory responses was sandwiched or surrounded by the areas of the inhibitory responses. 3. Optically recorded excitatory responses to pure tones had two components: a component sensitive to 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), a non-N-methyl-D-aspartate (non-NMDA) receptor antagonist, and a component sensitive to 2-amino-5-phosphono-valerate (APV), an NMDA receptor antagonist. Application of CNQX (5 microM) to the auditory cortex suppressed an early, but not a late, phase of the excitation; application of APV (100 microM) had the opposite effect. Concomitant application of CNQX and bicuculline methiodide (BMI, 4 microM), a GABAA receptor antagonist, increased the amplitude of the late phase 4-fold. This enhanced response was suppressed by APV. 4. These results indicate that (i) auditory cortical excitatory responses are mediated by both non-NMDA and NMDA receptors, (ii) inhibition is mediated by GABAA receptors, (ii) the excitatory bands are sandwiched or surrounded by GABAA receptor-mediated inhibitory areas and (iv) GABAA receptors effectively inhibit the NMDA, but not the non-NMDA, receptor-mediated excitation.

2-Amino-5-phosphonovalerate↗
PubMed1996

Aggressive non-Hodgkin's lymphoma with massive involvement of the right ventricle.

A 69-year-old women with malignant lymphoma (diffuse large:Working formulation) had associated with intracavital involvement of the right ventricle. The patient was referred to us for further examination with a diagnosis of heart failure. A tumor mass was detected by magnetic resonance imaging in the right ventricular outflow tract. While in the hospital the patient experienced cardiogenic shock due to neoplastic pulmonary embolism. The tumor was surgically resected and the patient was then treated with systemic chemotherapy. She went into complete remission and has continued in this state for six months. This case demonstrates that early diagnosis and intensive chemotherapy contribute to a good prognosis of patients with malignant lymphoma associated with massive involvement of a cardiac chamber. A review of the Japanese literature is presented.

Aged↗
PubMed1995

[Optic disc and choroidal circulation detected by dye-filling rate in indocyanine green angiography].

Dye-filling rate of optic disc and choroid in normal human subjects was investigated using indocyanine green infra-red videoangiography and computerized image analysis. Only relative changes in the circulation of disc and choroid could be studied and the ratio (D/M) of dye-filling rate in normal subjects (age ranged 23-62) in disc (D) to choroid (M) was reliable. Intraocular pressure (IOP) was elevated to two levels with a pneumatic suction-cup. When D/M at normal IOP was 1, mean D/M was 1. 29 when mean IOP was 26.8 mmHg, and 1.48 when mean IOP was 38.4 mmHg. The results suggest that IOP elevation produced less change in the disc circulation than in the choroid. The ratio of dye-filling rate of the disc at 38.4 mmHg to normal IOP was significantly correlated (P < 0.05) with perfusion pressure at normal IOP, showing that the autoregulatory mechanisms in the disc blood flow may possibly reach the limit especially in subjects whose perfusion pressure is low.

Adult↗
PubMed1994

Biomechanical characteristics of brain edema: the difference between vasogenic-type and cytotoxic-type edema.

Some of the basic biomechanical properties of edematous brain tissue have yet to be clarified. Therefore we measured regional tissue compliance and swelling isotropy/anisotropy in cat brain during development of vasogenic-type and cytotoxic-type edema. In vasogenic-type edema induced by cryogenic injury, the edematous white matter showed an increase of regional tissue compliance (indentation method), which paralleled the increase in the regional tissue water content (gravimetry). Swelling of the white matter due to edema was anisotropic, in which expansion transverse to the neuronal fibers caused by their dissociation was 91.1%, whereas longitudinal expansion was 2.3%. In cytotoxic-type edema induced by cerebral ischemia for 3 h, regional tissue compliance was decreased in the area suffering energy failure, which was visualized as an area of reduced succinic dehydrogenase activity. The ischemic gray matter showed isotropic swelling, and morphologically, prominent swelling of neuroglial cells. These marked differences in basic biomechanical properties between vasogenic-type and cytotoxic-type edema should be taken into account when analyzing the mechanism of edema-mediated tissue injury.

Animals↗
PubMed1994

Effects of NG-monomethyl-L-arginine, indomethacin, and aspirin on the vasodepressor response to low doses of endothelin-1 and endothelin-3 in rats.

Low doses (< or = 100 pmol/kg) of endothelin-1 (ET-1) and endothelin-3 (ET-3) elicited a fall in mean arterial pressure (MAP) and a dose-related reduction in hindquarter vascular resistance in anesthetized rats. The depressor response to low doses of ET-1 or ET-3 was short-lived (about 10 sec) and reversible. High doses (> or = 200 pmol/kg) of ET-1 and ET-3 elicited a biphasic response; an initial fall in MAP followed by a gradual increase in MAP. The pressor response to large doses of ET-3 was less than that to large doses of ET-1. On the other hand, the depressor response to low doses of ET-3 was similar to that to low doses of ET-1. Both ET-1 and ET-3 at low doses exhibited primarily a vasodilatory activity. Pretreatment with NG-monomethyl-L-arginine (L-NMMA), a compound that inhibits nitric oxide (NO) production by endothelial cells, attenuated the hypotensive and hindquarter vasodilating effects of low doses of these isopeptides, indicating that the hindquarter vasodilating responses to these peptides depend upon the release of NO from endothelial cells. On the other hand, pretreatment with either aspirin or indomethacin did not alter the hypotensive or the hindquarter vasodilating effects of either ET-1 or ET-3, indicating that cyclooxygenase products may not be involved in the vasodepressive mechanisms of these peptides. L-NMMA attenuated the vasodilating effects of these peptides, but did not completely inhibit the response, suggesting that NO production by endothelial cells plays only a partial role in the vasodilation of ET in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[A case of pulmonary malignant lymphoma associated with localized amyloid plaque].

A 51-year-old woman admitted to our hospital. Chest X-ray film showed infiltrations in left S4 region, which had been pointed out since two years before. On exploratory thoracotomy, lingual segmentectomy was performed because no metastatic lesions were found in the mediastinal and hilar lymph nodes. Pathological and immunohistological examinations revealed findings corresponding to pulmonary malignant lymphoma (diffuse, small cell type, B cell) with amyloid plaque. The patient is doing well 20 months after operation without any signs of recurrence. The clinical and histological findings of this case may suggest a close relationship between malignant lymphoma and production of amyloid.

Amyloidosis↗
PubMed1994

[A case of intrathoracic goiter composed of two tumors].

A 70-year-old female was referred to our hospital because of swelling at her frontal neck and an abnormal shadow on a chest X-ray film. CT scan and MRI showed a 11.0 x 7.5 cm well-demarcated tumor in the upper mediastinum. Thyroidal scintigraphy revealed an slight accumulation, leading to a diagnosis of intrathoracic goiter. During operation the mass was found to be composed of two tumors. The upper tumor was attached with fibrous adhesion to the right lobe of cervical thyroid but no connection. Histological examination showed follicular but not malignant adenoma of the thyroid.

Adenoma↗
PubMed1993

Spatio-temporal representation of sound intensity in the guinea pig auditory cortex observed by optical recording.

The spatio-temporal representation of sound intensity in the guinea pig auditory cortex was studied by optical recording with the aid of a voltage-sensitive dye. Changes in light intensity due to neural activity induced by sounds at various pressure levels were recorded with a 12 x 12 array of photodiodes. The amplitudes of the responses were displayed as sequential two-dimensional images. The iso-intensity bands revealed by neural activity were orthogonal to the isofrequency bands of tonotopical organization in the anterior field and dorsocaudal field. The frequency-intensity representation through the orthogonal organization varied with time. This mechanism may be adapted to the auditory cortex to sequentially process the three parameters of sound: frequency, intensity, and time. Furthermore, a new field was found in the ventrocaudal region of the auditory cortex. This field showed tonotopicity, but high thresholds.

Acoustic Stimulation↗
PubMed1993

Evaluation of rapid urease test for detection of Helicobacter pylori in gastric biopsy specimens.

Using 80 gastric biopsy specimens from patients with various gastroduodenal diseases, the isolation rate of H. pylori and urease activity of the biopsy specimens were examined. The sensitivity and specificity of the rapid urease test was 84.6% and 75.9%, respectively, for the cultivation of H. pylori. The mean number of H. pylori detected in urease-positive and negative biopsy specimens was 10(6.1 +/- 0.9) and 10(4.5 +/- 1.2) cfu/g specimens, respectively.

Adult↗
PubMed1993

Analysis of intestinal flora of a patient with congenital absence of the portal vein.

A 14-year-old female patient, admitted for a closer examination of liver tumour (hepatocellular adenoma), was diagnosed as having a congenital absence of the portal vein. The blood ammonia level (approximately 120 micrograms dl-1) in the superior mesenteric vein was markedly low compared to the normal value of 300-350 micrograms dl-1 in the portal vein. The decreased ammonia concentration and urease activity of the patient's faeces were demonstrated. The dominant intestinal flora in the faeces of the patient, before operation, was Bifidobacterium sp., Bifidobacterium breve, Bifidobacterium lonqum, Lactobacillus plantarum, and after the operation Bacteroides vulgatus, Veillonella parvula, Peptococcus magnus Bifidobacterium longum. In contrast, Bifidobacterium bifidum, Bacteroides ureolyticus, Bacteroides ovatus and Bacteroides distasonis, B. ovatus, Bifidobacterium adolescentis were dominant flora in the faeces of two healthy volunteers, respectively. Among microorganisms isolated from the patient, Morganella morganii, Candida sp., Eubacterium aerofacience and Eubacterium rectale were strongly positive in urease activity in vitro; Streptococcus mitior, Staphylococcus intermedius, Micrococcus kristinae, Selenomonas ruminantum, Bacteroides ureolyticus and Lactobacillus casei ss. pseudoplantarum from the healthy volunteers. These results imply the homeostatic regulation system of faecal ammonia concentration by urease-producing microorganisms in the patient.

Adolescent↗
PubMed1993

[An adult case of left ventricular-right atrial communication with a false aneurysm of membranous septum].

A case of left ventricular-right atrial (LV-RA) communication associated with a false aneurysm of membranous septum is presented. The patient was a 51-year-old woman. Using a left ventriculography this case was diagnosed preoperatively as LV-RA communication. We found that the right atrium was directly communicated with the left ventricle through a fibrous membranous aneurysm adhering to the septal leaflet of the tricuspid valve. It was suggested that a false aneurysm, made by jet lesion from the left ventricle, perforated to the right atrium. So the current case was considered an acquired infravaluvular type LV-RA communication formed in the course of the natural closure of the membranous ventricular septal defect.

Aneurysm, False↗
PubMed1992

Spatio-temporal pattern of frequency representation in the auditory cortex of guinea pigs.

The spatio-temporal pattern of sound-evoked neural activity in the guinea pig auditory cortex was studied by optical recording with the aid of voltage-sensitive dye. Changes in light intensity induced by sounds at various frequencies and pressure levels were recorded with a 12 x 12 array of photodiodes. The amplitudes of the responses were displayed as sequential two-dimensional images. Tonotopical organization was found in two subdivisions of the auditory cortex, the anterior field (field A) and the dorsocaudal field (field DC). The frequency gradients in fields A and DC had a mirror-image relationship. This agrees with results obtained by the microelectrode technique. However, the tonotopic response observed in our study was transient. The focal activity that began in field A propagated in two directions; dorsally along the iso-frequency bands in field A, and caudally toward field DC. This suggests that the sound information processing initiates at field A, and its outputs are transferred to field DC, which is probably a hierarchically higher center.

Acoustic Stimulation↗
PubMed1992

The influence of stimulus duration on the delay tuning of cortical neurons in the FM bat, Myotis lucifugus.

1. Echolocating bats use echo delay as the primary cue to determine target distance. During target-directed flight, the emitted pulses increase in repetition rate and shorten in duration as distance decreases. To determine how these parameters affect the delay tuning of neurons in the auditory cortex of the awake bat, Myotis lucifugus, we examined the responses of 104 delay-sensitive neurons as the pulse repetition rate (PRR) and duration were independently varied. Stimulus duration of 4, 2 and 1 ms and PRR of 5-100/s were used for both the pulse and echo to determine delay sensitivity. These parameter ranges span those used during the search, approach, and the initial terminal phases of echolocation. 2. As the stimulus duration was shortened, the range of PRRs for delay sensitivity was extended to higher rates in 41% of the neurons, narrowed or disappeared in 40%, and remained unchanged in 4%. The remaining 15% were not categorized since it was not possible to determine a trend in which the range of delay-sensitive PRRs changed with stimulus duration. 3. Three types of tracking neurons (i.e., neurons that change their best delay during target-directed flight) were found. For the first type, the best delay (BD) shortened with shorter stimulus duration, for the second type, BD shortened with both shorter stimulus durations and higher PRRs, and for the third type, BD shortened with higher PRRs. 4. These results suggest that the stimulus parameters of sonar emission influence delay tuning and hence processing by cortical neurons in FM bats.

Acoustic Stimulation↗
PubMed1992

[Chronic fatigue syndrome--51 cases in the Jikei University School of Medicine].

Between April 1991 and August 1992, we diagnosed 51 cases of CFS who met definition of CFS designated by CDC, 1988. They are 41 female and 11 male, and 78% are women. At first visit, their ages are ranged from 16 to 64 years old, and approximately 45% is 20 to 30 years old. In periods of illness from onset, 39.2% of the patients are in period of 6 month to 1 year, 19.6% within 2 years, and 15.6% within 3 years, respectively. The sufferer who have symptoms of CFS over 10 years long are in 6 cases. Most of patients have already been examined by many other clinics and hospitals. They have been told as no abnormal medical condition, or often as neurosis, depressive state and autonomous imbalance etc. Interesting things are trigger of CFS. 77.5% of patients have onset of flu-like symptom, including 5 cases of acute infectious mononucleosis. In many female patients, symptoms of CFS begun after hand work in addition to psychological factors. Specific laboratory results are not shown in CBC, urinalysis, biochemical studies and inflammatory marhers. 6 cases hare positive Rheumatoid factor and positive ANF are shown in 16 cases (31.3%). Specific patterns of anti EBV antibodies are not shown. Lymphocyte subsets used by monoclonal antibodies are not specific. At the present, prognosis is good and 56.8% of CFS patients are generally improved. For severe cases, NSAID, Sulpiride, Amitryptiline and minor tranquilizer are used.

Adolescent↗
PubMed1992

[A case with Graves' disease whose TBII index was decreased after heart surgery].

This case report describes a patient with Graves' disease who underwent heart surgery and we studied changes in thyroid hormone and antithyroid autoantibodies. TBII index of this case, which was high value before surgery, was decreased after surgery for two years, and the patient did not need any antithyroid drug. It is suggested that these changes may be due to cardio-pulmonary bypass and administration of steroids during heart surgery. This case indicates that heart surgery may influence the clinical course of Graves' disease.

Autoantibodies↗
PubMed1991

Responses of medial geniculate neurons to species-specific vocalized sounds in the guinea pig.

We obtained extracellular single-unit recordings in the medial geniculate body (MG) of guinea pigs, and studied the responses of MG neurons to pure-tone stimuli and to species-specific vocalized sounds. Of pure-tone sensitive neurons with a characteristic frequency (CF) within the frequency range of the vocalized sounds, only 29% responded to the vocalized sound, 6% were inhibited by the vocalized sound, and 30% showed no response to the vocalized sounds. The responsiveness of MG neurons to the vocalized sound was low. The majority of neurons responsive to the vocalized sounds showed discharge patterns which were not predictable from response properties to pure tones. These results suggest the presence of neurons which specifically respond to the complex feature of sound in the subcortical MG level of the guinea pig.

Acoustic Stimulation↗
PubMed1991

[Studies on nonthyroidal illness after heart surgery].

The concentrations of pituitary hormones (TSH and PRL), thyroid hormones (free-T4 and free-T3), thyroid hormone binding protein (TBG) and lipids (TG and FFA) in the blood were measured in order to examine the physiology of nonthyroidal illnesses that occurred as a result of heart surgery as well as their effects on the pituitary and thyroid glands. The subjects of the study consisted of 30 adults with congenital and acquired heart disease. Blood concentrations of TSH, PRL, free-T4, free-T3, and TBG decreased, and those of FFA increased, on the 2nd day following surgery. On the 2nd day following surgery, the decrease in the concentrations of free-T4 and free-T3 in the blood were considered due to a decrease in secretion of T4 from the thyroid gland, as well as due to a decrease in the activity of iodothyronine 5'-deiodinase in the peripheral organs. In the 3rd week following surgery, the concentrations of these items returned to their original values on the day prior to surgery.

Adult↗