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Biomedical subjects

I Taniguchi

Publications and source records attributed to I Taniguchi.

At least 19 recordsLinked to original sources
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↗
PubMed1990

Enzyme immunosensors based on electropolymerized polytyramine modified electrodes.

Highly sensitive amperometric enzyme immunosensors for human immunoglobulin G (IgG) were prepared on the basis of electrogenerated polytyramine (PTy, tyramine = p-(2-aminoethyl)-phenol) modified electrodes. Properties of PTy films changed depending on electrolysis conditions. On the basis of the found properties of the films, an effective IgG sensor was prepared: a PTy film was formed first from an acid solution on a Pt electrode, and the surface was further covered with a PTy film from an alkaline methanol solution to give a PTy doubly coated electrode on which anti-IgG was then immobilized. This electrode provided a large surface area with little non-specific adsorption of proteins. By means of the competitive enzyme immunoassay technique using glucose oxidase (GOD) labeled IgG conjugates, IgG was determined in the concentration range of c. 10 pg/ml-1 mg/ml from the oxidation current of H2O2 generated by the enzyme (GOD) reaction using the above IgG sensor. Also, an anti-IgG immobilized electrode, prepared by using a Pt electrode singly covered with a PTy film from an alkaline methanol solution, acted as an effective IgG sensor with a detection limit for IgG of c. 100 pg/ml.

Antibodies, Anti-Idiotypic↗
PubMed1990

Hormonal and clinical effects of multifollicular puncture and resection on the ovaries of polycystic ovary syndrome.

Sixteen women with polycystic ovary syndrome (PCOS) were treated with laparoscopic multifollicular puncture and resection (MPR), an original technique which we substitute for ovarian wedge resection. Serum luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T), estrone (E1), estradiol (E2), androstenedione (A) and dehydroepiandrosterone sulphate (DHEAS) were measured daily before and after the operation. Clinically, 15 of the 16 patients (93.8%) exhibited spontaneous ovulation and pregnancies occurred in 8 patients (50%). Significant hormonal changes were observed in serum T. Serum T levels dropped in response to the treatment and remained low for 5 days. Serum E1, A, DHEAS and LH levels were elevated before treatment and did not change after the operation. Serum E2 and FSH levels were within the normal range before the treatment and did not change after the operation. We conclude that surgical treatment for PCOS patients should consist of laparoscopic MPR.

Androstenedione↗
PubMed1990

[Right ventricular dysfunction of mitral valve stenosis].

Right ventricular function was studied in 9 patients with mitral valve stenosis who underwent mitral valve replacement (St. Jude Medical valve 29-31 mm) (MVR). The right ventricular systolic pressure/end-systolic volume index (RVSP/ESVI) correlated well with right ventricular ejection fraction (RVEF) in the normal control group thus it considered to be a index of right ventricular contractility. At rest, RVEF in the MVR group was significantly lower than that in the control group. However there was no difference in the RVSP/ESVI between both groups. In the MVR group, the total pulmonary resistance index (TPRI) and mean pulmonary arterial pressure (mPAP) were higher than those in the control group. During exercise, the RVSP/ESVI became higher in both groups, but RVEF did not increase in the MVR group. In the control group, RVEF became higher during exercise. In addition, TPRI and mPAP increased in the MVR group but the control group did not show significant changes during exercise. In conclusion, low RVEF after MVR, which reflects pump function of the right ventricle, was not caused by contractile dysfunction of the right ventricle but mainly by excess afterload due to irreversible pulmonary vascular resistance persisting after operation as a result of chronic pulmonary vascular hypertension.

Adult↗
PubMed1989

Correlation between the size of song control nuclei and plumage color change in orange bishop birds.

Adult male orange bishop birds (Euplectes franciscanus) develop beautiful nuptial plumage during the breeding season, but have the same sober plumage as the female during the non-breeding season. The male conspecific song is highly stereotyped during nuptial plumage. Large volume differences were found in two song control nuclei in the cerebrum between the male and female during the breeding season, and in the same nuclei of the males during the breeding and non-breeding seasons. The seasonal changes in the size of cerebral song control nuclei were dominant in the male and may not correlate with the improvement or modification of the song repertories.

Animals↗
PubMed1988

Functional laminar and columnar organization of the auditory centers in echolocating Japanese greater horseshoe bats.

During echolocation, bats coordinately employ the vocalization system to emit orientation sounds and the auditory system to hear returning echoes. The brain in these animals should be functionally organized to process such biologically significant sounds. Here we utilized the autoradiographic 2-deoxy-[14C]glucose (DG) method to visualize functional organization of the auditory centers of echolocating Japanese greater horseshoe bats, Rhinolophus ferrumequinum nippon. Autoradiographic color images made from the brains of echolocating bats revealed a functional laminar structure in the inferior colliculus. Furthermore, a functional columnar organization appeared in the auditory cortex during echolocation. These laminar and columnar organization were not observed in the brain of resting bats.

Acoustic Stimulation↗
PubMed1988

Abnormal polyamine metabolism in hypertensive cardiac hypertrophy.

In order to assess myocardial hypertrophic activity during the process of hypertensive cardiac hypertrophy in the presence and absence of treatment with anti-hypertensive agents, we analyzed myocardial polyamine concentrations in spontaneous hypertensive (SHR) rats and control rats of Wistar Kyoto (WKY) strain. The anti-hypertensive agents studied were diltiazem, hydralazine and captopril, each of which was administered for 5 weeks. In comparison with WKY rats, SHR rats showed elevated blood pressure and enlarged hearts with higher myocardial spermidine concentration. Although blood pressure was lowered in the diltiazem-treated SHR rats, heart weight and myocardial spermidine concentration increased as in untreated SHR rats. In the hydralazine-treated group increases in both blood pressure and myocardial spermidine concentration were suppressed, while an increase in heart weight was not. In the captopril-treated group, increases in blood pressure, heart weight and spermidine concentration were all suppressed. Since spermidine level appears to be a sensitive indicator of hypertrophic activity in the heart, this study suggests that captopril exerts an inhibitory effect on hypertensive cardiac hypertrophy whereas diltiazem does not. It also suggests that hypertrophy may reach a certain plateau level earlier in the hydralazine-treated animals than in others.

Animals↗
PubMed1987

The personalized auditory cortex of the mustached bat: adaptation for echolocation.

1. In the mustached bat, Pteronotus parnellii, the "resting" frequency of the constant-frequency component of the second harmonic (CF2) of the orientation sound (biosonar signal) is different among individuals within a range from 59.69 to 63.33 kHz. The standard deviation of CF2 resting frequency is 0.091 kHz on the average for individual bats. The male's CF2 resting frequency (61.250 +/- 0.534 kHz, n = 58) is 1.040 kHz lower than the female's (62.290 +/- 0.539 kHz, n = 58) on the average. Females' resting frequencies measured in December are not different from those measured in April when almost all of them are pregnant. Therefore, the orientation sound is sexually dimorphic. 2. In the DSCF (Doppler-shifted CF processing) area of the auditory cortex, tonotopic representation differs among individual bats. The higher the CF2 resting frequency of the bat's own sound, the higher the frequencies represented in the DSCF area of that bat. There is a unique match between the tonotopic representation and the CF2 resting frequency. This match indicates that the auditory cortex is "personalized" for echolocation and that the CF2 resting frequency is like a signature of the orientation sound. 3. If a bat's resting frequency is normalized to 61.00 kHz, the DSCF area overrepresents 60.6-62.3 kHz. The central region of this overrepresented band is 61.1-61.2 kHz. This focal band matches the "reference" frequency to which the CF2 frequency of a Doppler-shifted echo is stabilized by Doppler-shift compensation. 4. Since DSCF neurons are extraordinarily sharply tuned in frequency, the personalization of the auditory cortex or system is not only suited for the detection of wing beats of insects, but also for the reduction of the masking effect on echolocation of consepecific's biosonar signals. 5. Because the orientation sound is sexually dimorphic and the auditory cortex is personalized, the tonotopic representation of the auditory cortex is also sexually dimorphic.

Acoustic Stimulation↗
PubMed1986

Response properties of FM-FM combination-sensitive neurons in the auditory cortex of the mustached bat.

For echolocation, the mustached bat, Pteronotus parnellii rubiginosus, emits orientation sounds (pulses) and listens to echoes. Each pulse is made up of 8 components, of which 4 are constant frequencies (Cf 1.4) and 4 are frequency-modulated (FM 1-4). Target-range information, conveyed by the time delay of the echo FM from the pulse FM, is processed in this species by specialized neurons in a part of the auditory cortex known as the FM-FM area. These cortical neurons are responsive to pulse-echo pairs at specific echo delays. The essential components in the sound pair include the pulse FM1 followed by an echo FMn (n = 2, 3 or 4). Downward sweeping FM1-FMn sounds that are similar to those the animal naturally hears during echolocation are the most effective in evoking facilitative responses. Most FM-FM neurons, however, still exhibit facilitative responses to stimulus pairs consisting of upward sweeping FM sounds and/or pure tones at frequencies found in FM sweeps. The magnitude of facilitation is altered by changes in echo rather than pulse amplitude. Neurons characterized by shorter best delays (or echoes from closer targets) do not require larger best echo amplitudes for facilitation.

Animals↗
PubMed1985

Cardiorespiratory arrest in a patient with advanced diabetic autonomic neuropathy.

A 53-year-old diabetic woman who had been diabetic for 14 years had recurrent episodes of cardiorespiratory arrest, which were easily resuscitated by a few chest massages. In 2 of 4 episodes a radial pulse was detected, so respiratory arrest was thought to be a primary event. Pentazocine was injected several hours prior to each of the 3 episodes. This was considered to be a precipitating factor. From the first episode of cardiorespiratory arrest, she received oxygen inhalation. When oxygen inhalation was withdrawn for 5-10 min, she became cyanotic. This was considered to be a sign of lack of hypoxic drive mediated by peripheral chemoreceptors. Ventilatory responses to hypercapnia was markedly decreased, indicating impaired central chemosensitivity. The possibility that impaired chemosensitivity could be a cause of respiratory arrest was suggested.

Autonomic Nervous System Diseases↗
PubMed1985

Erythrocyte filterability and adenosine triphosphate levels in normal pregnancy and puerperium.

The filterability of erythrocytes was determined by a filtration method using erythrocytes suspended either in phosphate-buffered saline or in native plasma. Erythrocytes from pregnant women in the second and third trimester were significantly less filterable than those from non-pregnant women. On 0 to 1 day after delivery, erythrocyte filterability was further reduced, being significantly lower than that in the third trimester of pregnancy. Erythrocyte adenosine triphosphate (ATP) levels during pregnancy were not significantly different but in early puerperal period it was significantly lower than that in non-pregnant women. One month after delivery the filterability and ATP content of erythrocytes returned to the non-pregnant levels. The size and hemoglobin concentration of erythrocytes were unchanged during pregnancy and puerperium.

Adenosine Triphosphate↗