PubMed Health⌕ Search

Biomedical subjects

H Furuse

Publications and source records attributed to H Furuse.

18 recordsLinked to original sources
PubMed2000

Fluid viscosity of Aureobasidium pullulans cultures obtained at two different initial pH values.

Aureobasidium pullulans IAM 5060 grown in media with initial pHs of 6 and 7 differed in its production of exopolysaccharides (EPS). Under the latter condition, EPS of a high molecular weight was produced in an especially large amount. The viscosity of the culture broths and the EPS solutions obtained by removing the microbial cells exhibited a marked non-Newtonian and complex behavior depending on the measurement method. The nature of the viscosity of the fluids is explained by means of several structural models of their constitutive particles.

Journal Article↗
PubMed1999

Analysis of flow behavior of non-Newtonian fluids based on a concept of traveling force.

The non-Newtonian flow behavior of a culture fluid with suspended adhesive particles of microbes and polysaccharides is analyzed in this study based on a new concept. The concept assumes that the force generated by the contact between particles under shearing flow due to mixing is decreasingly transmitted through the fluid in radial directions. A viscosity equation that includes the degree of force transmisson is derived by considering the shear stress to the force. On the other hand, the shear stress dependence on the concentration of bound particles is expressed in an equation by introducing an effective shear stress that works on the contact sites of the bindings and varies the concentration. Relating the degree of force transmission to the concentration derives a non-Newtonian viscosity equation in terms of shear stress (or shear rate), in which zero-shear viscosity is correlated with both the particle concentration and molecular weight of polymers. It is confirmed that calculations based on the equation are in good agreement with experimental results previously reported for aqueous solutions of several polysaccharides.

Journal Article↗
PubMed1998

Effect of the mono- and tetra-sialogangliosides, GM1 and GQ1b, on long-term potentiation in the CA1 hippocampal neurons of the guinea pig.

Effects of the mono- and tetra-sialogangliosides, GM1 and GQ1b, on long-term potentiation (LTP) were investigated in the CA1 neurons of guinea-pig hippocampal slices. The magnitude of LTP induced by a strong tetanus (100 Hz, 100 pulses) was not significantly affected by application of either ganglioside. In contrast, when LTP was induced by a weak tetanus (100 Hz, 4 pulses), a significantly greater LTP was induced in the presence of either ganglioside. Similarly, when slices were incubated in low-Ca2+ (1.0-1.1 mM) medium for more than 2 h, the LTP was usually small or absent, but showed a significant increase in amplitude of population spike (A-PS) when the slices were incubated with either GM1 or GQ1b (4-5 microg/ml). In addition, the application of GQ1b (4 microg/ml) reversed the blocking effect of an NMDA-receptor antagonist, APP-5 (10 microM), on the induction of LTP and resulted in forming LTP. Based on these findings, we conclude that GM1 and GQ1b exert positive modulatory effects on the induction of LTP in hippocampal CA1 neurons and suggest that GM1 and GQ1b may participate in the induction of LTP as donors of Ca2+ ions.

Animals↗
PubMed1998

Holmium:YAG laser resection of the prostate versus visual laser ablation of the prostate and transurethral ultrasound-guided laser induced prostatectomy: a retrospective comparative study.

BACKGROUND: Transurethral resection of the prostate (TUR-P) is the gold standard for treating symptomatic benign prostatic hyperplasia (BPH) despite some perioperative morbidity. As a minimally-invasive alternative to TUR-P, a neodymium:YAG laser, and more recently a holmium:YAG laser, have been used in transurethral surgery for BPH. In order to assess the safety and efficacy of various BPH treatments, the outcome in patients treated with transurethral ultrasound-guided laser induced prostatectomy (TULIP), visual laser ablation of the prostate (VLAP) and holmium:YAG laser resection of the prostate (HoLRP) were retrospectively compared. METHODS: From May 1995 to August 1996, 60 patients with symptomatic BPH underwent TULIP (n=20), VLAP (n=20), and HoLRP (n=20). All patients were evaluated preoperatively and at 1 and 3 months postoperatively by the International Prostate Symptom Score (IPSS), the IPSS quality-of-life score (QOL), maximum flow rate (MFR), prostate volume, and residual urine volume. RESULTS: The preoperative mean IPSS was 18.5, 19.3, and 19.6 and the mean MFR was 6.3, 6.9, and 6.1 mL/sec in the TULIP, VLAP, and HoLRP groups, respectively. At 1 month after surgery, the mean IPSS was 10.2, 9.5, and 4.7 and the mean MFR was 9.6, 13.4, and 18.7 mL/sec while at 3 months the mean IPSS was 6.2, 6.1, and 3.6 and the mean MFR was 14.1, 16.0, and 21.5 mL/sec in patients treated with TULIP, VLAP, and HoLRP, respectively. No serious complication occurred in any patient. CONCLUSION: Although HoLRP requires expertise, it appears to be a promising treatment modality for BPH.

Aged↗
PubMed1996

Roles of dopamine receptors in long-term depression: enhancement via D1 receptors and inhibition via D2 receptors.

The effects of both the activation and the blockade of D1 or D2 dopamine receptors on long-term depression (LTD) of synaptic transmission, and the involvement of NMDA and GABA receptors in LTD, were investigated in CA1 neurons of rat hippocampal slices. Low-frequency stimulation (LFS, 450 pulses at 1 Hz) produced LTD of the slope of field EPSPs (-14.3%, mean, n = 10). The induction of LTD was blocked by the NMDA receptor antagonist, AP5 (1.4%, n = 7), by the D1 receptor antagonist, SCH-23390 (3.5%, n = 8), or by the D2 receptor agonist, LY-171555 (4.4%, n = 8). Either the activation of D1 receptors by SKF-38393 or the blockade of D2 receptors by sulpiride produced significantly larger LTD than the control LTD (-31.1%, n = 11; -30.6%, n = 9, respectively). Although LTD was blocked by picrotoxin, a GABAA receptor/Cl- channel antagonist (4.9%, n = 8), LTD was produced by LFS in the medium containing both SKF-38393 and picrotoxin (-27.3%, n = 7). These results indicate that: (1) the induction of LTD by LFS in hippocampal CA1 neurons is under the influence of both NMDA and GABA receptors; (2) both D1 and D2 receptors are involved in the modulation of LTD in that the activation of D1 receptors enhances LTD, while that of D2 receptors inhibits LTD, and (3) while the induction of LTD is blocked by picrotoxin, this effect is superseded by SKF-38393.

2-Amino-5-phosphonovalerate↗
PubMed1996

The long-term suppressive effect of prior activation of synaptic inputs by low-frequency stimulation on induction of long-term potentiation in CA1 neurons of guinea pig hippocampal slices.

We have investigated the effects of prior activation of afferent inputs by a train of low-frequency stimulation (LFS) on the induction of long-term potentiation (LTP) induced by high-frequency stimulation (tetanus, 100 Hz, 100 pulses) in CA1 neurons of guinea pig hippocampal slices. The parameters of the LFS were altered systematically: the frequency (1 or 5 Hz); the number of pulses (80, 200 or 1000); and the time lag from the LFS to the tetanus (20, 60 or 100 min). Conditioning effects of the LFS on the induction of LTP were evaluated in terms of the slope of the field excitatory postsynaptic potential (S-EPSP) and the amplitude of the population spike (A-PS). LTP could reliably be induced by 100 Hz tetanic stimulation delivered to a naive slice. In contrast, the attempt to induce LTP 60 min after LFS of 200 or 1000 pulses at 1 Hz resulted only in short-term potentiation while the LFS itself produced no significant change in the responses. The suppressive effect on LTP was significantly reduced for 1 Hz LFS with a smaller number of pulses (80 pulses), or a shorter (20 min) or longer (100 min) time lag from the LFS to the tetanus, or with LFS at a higher frequency (5 Hz). When the LFS of 1000 pulses at 1 Hz was delivered in the presence of the N-methyl-D-aspartate (NMDA) receptor antagonist AP5 (D,L-4-amino-5-phosphonovalerate, 50 microM), which was washed out after the end of the LFS, the tetanus given 60 min after application of the LFS produced stable LTP, indicating the involvement of NMDA receptor/channels in the mechanisms of this particular form of synaptic plasticity-long-term suppression of LTP.

2-Amino-5-phosphonovalerate↗
PubMed1995

The mechanism of ATP-induced long-term potentiation involves extracellular phosphorylation of membrane proteins in guinea-pig hippocampal CA1 neurons.

The mechanism of ATP-induced long-term potentiation was studied pharmacologically using guinea-pig hippocampal slices. Application of 1-10 microM ATP for 10 min transiently depressed and then slowly augmented the synaptic transmission in CA1 neurons leading to long-term potentiation (LTP). This ATP-induced LTP was blocked by the addition of K-252b, an ecto-protein kinase inhibitor, but was enhanced by the addition of RK682, an ecto-phosphatase inhibitor, both of which do not permeate the cell membrane. These results suggest that ATP applied to the perfusate provides enough substrate for ecto-protein kinase to induce LTP through phosphorylation of extracellular domains of membrane proteins in CA1 neurons.

Adenosine Triphosphate↗
PubMed1995

Voltage-gated Ca2+ channel blockers, omega-AgaIVA and Ni2+, suppress the induction of theta-burst induced long-term potentiation in guinea-pig hippocampal CA1 neurons.

It is widely believed that a rise in post-synaptic calcium concentration ([Ca2+]i) is a necessary step in the induction of long-term potentiation (LTP) (Bliss and Collingridge, Nature, 361 (1993) 31-39). In this experiment, we examine the involvement of voltage-gated Ca2+ channels (VGCC) in the induction of AP5-sensitive LTP induced by theta-burst stimulation in guinea-pig hippocampal CA1 neurons. The VGCC blockers, Ni2+ (25 microM, T-channel blocker) or omega-AgaIVA (60 nM, P-channel blocker), which have no effect on synaptic transmission, suppress 60% or 78% of the theta-burst induced LTP, respectively. This implies that Ca2+ entry through VGCC is an important step in this form of LTP.

2-Amino-5-phosphonovalerate↗
PubMed1995

[Deoxycorticosterone-producing adrenocortical carcinoma--a case report].

A 39-year-old male presented with gross hematuria and left lower abdominal discomfort. Excretory urography showed a left ureteral stone and hydronephrosis. CT scans and magnetic resonance imaging showed a solid mass at the upper pole of the left kidney. Angiography revealed a hypervascular lesion at this area. The laboratory data showed a slightly decreased serum potassium level. In the endocrinological study, the serum deoxycorticosterone (DOC) level was markedly elevated. There was, however, no evidence of hypertension. The operation was performed on November 13, 1992. The tumor was almost separated from the left kidney, but an aberrant artery which divided from the renal artery and penetrated the renal parenchyma was found. Therefore, we had to carry out en bloc removal of the tumor together with the left kidney and the ureter which contained the ureteral stone. Pathological diagnosis was adrenocortical carcinoma. After the operation, hypokalemia and the serum concentration of DOC returned to normal range. Therefore, the tumor was diagnosed as DOC producing adrenocortical carcinoma. The patient was discharged 30 days after the operation with uneventful postoperative course. He received 2.5 g of op'-DDD a day. There was no evidence of distant metastasis or local recurrence 12 months after the operation. Nineteen cases of DOC producing adrenocortical tumor have been reported in the world literature. A case and a review of the literature are herein reported.

Adrenal Cortex Neoplasms↗
PubMed1995

[Complete remission of prostate cancer after LH-RH agonist neoadjuvant therapy: a case report].

We report a case of prostate cancer showing a complete remission after LH-RH agonist neoadjuvant therapy. A 69-year-old man was referred to our department complaining of pain on urination and urge incontinence. The serum prostate specific antigen (PSA) level was 41.6 ng/ml. Needle biopsy specimens from both lobes revealed moderately differentiated adenocarcinoma. Chest X-ray, computed tomographic (CT) scan, and bone scintigraphy demonstrated neither distant metastasis nor local invasion. LH-RH agonist was administered on a monthly basis as neoadjuvant therapy. After 4 injections, pelvic lymph node dissection and radical prostatectomy were performed on January 11, 1993. Thorough examination did not reveal any cancer cells in the removed specimen. The patient was discharged 30 days after the operation and has shown no evidence of distant metastasis or local recurrence as long as 19 months later.

Adenocarcinoma↗
PubMed1994

Pure-tone threshold prediction by 80-Hz amplitude-modulation following response.

The usefulness of 80-Hz amplitude-modulation following response (AMFR) detected by phase spectral analysis to predict the hearing threshold during sleep was evaluated in 20 normal adults, 8 normal children and 37 children with hearing impairment. The onset effect of tonal stimulus on 80-Hz steady state response was studied in normal adults during sleep and a threshold of 80-Hz AMFR detected by phase spectral analysis was compared with that of ABR elicited by tone pips in children during sleep. Although 80-Hz AMFR is not appropriate for the assessment of hearing in adults, it appears useful for evaluating hearing in young children during sleep. Hearing prediction by 80-Hz AMFR appears to be more accurate than that by ABR elicited with tone pips. The onset effect of stimulus on 80-Hz AMFR with modulation depth of 95% was less than 80-Hz SSR evoked by clicks.

Acoustic Stimulation↗
PubMed1994

Effects of aging on amplitude-modulation following response.

Phase spectral analysis as developed by Fridman (1982) was used to detect amplitude-modulation following response (AMFR). The threshold of AMFR was determined with greater sensitivity and accuracy by phase spectral analysis than by visual analysis. Using this method, a modulation frequency (MF) of 80 Hz was found optimal for detecting AMFR in young children (ranging in age from 2 to 4 years) during sleep, for whom there is no advantage in recording 40-Hz steady-state responses. To determine the optimal MF for detecting AMFR during sleep in children less than 2 years of age and age limitation for using 80-Hz MAFR in objective audiometry, AMFR as a function of MF was investigated during sleep in 25 children with normal hearing ranging from 4 months to 15 years of age, and 10 normal hearing adults. The stimulus was a 1000 Hz, 50 dBnHL sinusoidally amplitude modulated tone with a modulation depth of 95%. MF was varied from 20 to 200 Hz in 20 Hz steps. Response was determined by phase spectral analysis and the S/N ratio calculated by spectral amplitude at the modulation frequency and noise level around the modulation frequency using fast Fourier transform. Phase spectral analysis showed AMFR at MF of 80 Hz to be the most stable and reliable in all children during sleep among MFs from 20 to 200 Hz. Spectral amplitude analysis demonstrated 80-Hz AMFR to have a high S/N ratio in all children.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMed1994

Detectability of amplitude-modulation following response at different carrier frequencies.

To assess the detectability of amplitude-modulation following response (AMFR) elicited at different carrier (CFs) and modulation frequencies (MFs) during sleep, as well as the usefulness of AMFR in evoked response audiometry, AMFR was examined in 10 adults with normal hearing while sleeping. The stimulus was a 50 dBnHL sinusoidally amplitude-modulated (SAM) tone with a modulation depth of 95%. The MF of the stimulus tone was varied from 20 to 120 Hz in 20 Hz steps and CFs were 500, 1000, 2000 and 4000 Hz. An SAM tone with a CF of 20,000 Hz was used for stimulation in 5 subjects to confirm that the response did not contain any artifact. Response was determined by phase spectral analysis. The component synchrony measure of AMFRs at MF of 40 Hz (40-Hz AMFR) was high at lower CFs, but 40-Hz AMFRs at higher CFs were unreliable. The detectability of 80-Hz AMFR was high for all CFs. It was confirmed that the response waveform was not contaminated by any electromagnetic artifact. Eighty-Hz AMFR detected by phase spectral analysis should thus be useful for predicting frequency-specific hearing thresholds during sleep.

Acoustic Stimulation↗
PubMed1994

An experimental study on the generator of amplitude-modulation following response.

To clarify the contribution of the auditory cortex and the inferior colliculus to amplitude-modulation following response (AMFR), lesion experiments were conducted on 8 cats. Bilateral auditory cortices of 2 cats were aspirated, and the right inferior colliculus of 3 cats, and the left inferior colliculus of another 3 cats were electrocoagulated to make lesions. Auditory brainstem response (ABR) evoked by clicks and AMFR elicited with 1000 Hz sinusoidally amplitude-modulated tones, at modulation frequencies (MF) of 20-200 Hz in 20-Hz steps, were examined before and after making lesions. Stimulus intensity was fixed at 90 dB SPL in both responses. AMFR was detected by phase spectral analysis using fast Fourier transformation. No change was observed in the phase spectral analysis of AMFR after bilateral cortical lesions. Remarkable changes were observed in AMFRs at MFs lower than 80 Hz and 200 Hz after lesions in the ipsilateral inferior colliculus and at all MFs after contralateral lesions of the inferior colliculus, while no such change was observed in ABR. The results suggest that the auditory cortex is not the source of AMFR, but that the inferior colliculus has great impact on the generation of AMFR at modulation frequencies of 20 to 200 Hz.

Acoustic Stimulation↗
PubMed1992

[Motor adaptation in the Bielschowsky head-tilt test in cases of superior oblique palsy].

To elucidate a motor adaptation phenomenon in the Bielschowsky head-tilt test in cases of superior oblique palsy, a gain of the otolith-ocular reflex was studied. The amplitude of ocular counter-rolling (OCR) of the non-paretic eye was measured with a photographic method, using limbal conjunctival marks as landmarks which were marked with indigo carmine. The average preoperative OCR of the non-paretic eye was 10.49 degrees at 30 degrees of head tilt to both sides, but after corrective surgery in the paretic eye the OCR of the non-paretic eye decreased to 8.43 degrees. To clarify the relation between OCR, duration of palsy and vertical deviation of the Bielschowsky head-tilt test (BHP), which was the difference of vertical deviation measured with the head tilted to the left and right shoulders at an angle of 30 degrees, the BHP/OCR ratio was calculated. We found no relation between BHP and OCR, but the BHP/OCR ratio increased proportionally in cases of long-standing palsy, From these results an increased BHP/OCR ratio could be an adaptive phenomenon caused by secondary innervational changes or muscle contracture to minimizing the contralateral head tilt to maintain binocular single vision.

Adaptation, Physiological↗
PubMedDate not supplied

Reliability of 80-Hz amplitude-modulation-following response detected by phase coherence.

The reliability and frequency specificity of the 80-Hz amplitude-modulation-following response (80-Hz AMFR) during sleep detected by phase coherence as a measure of the hearing threshold was evaluated in 169 affected ears of 125 children with hearing impairment. The 80-Hz AMFR at a carrier frequency of 1000 Hz was monitored in all 169 ears and the auditory brainstem response (ABR) elicited by 1000-Hz tone pips was evaluated in 93 ears. Both responses were examined during sleep, and the thresholds were compared with the behavioral hearing threshold, which was determined by standard pure-tone audiometry or play audiometry. In 24 ears of 22 children with various patterns of audiogram, the 80-Hz AMFR was examined at different carrier frequencies, and the threshold pattern was compared with the pure-tone audiogram to investigate the frequency specificity of 80-Hz AMFR. The mean and standard deviation of the difference between the 80-Hz AMFR at a carrier frequency of 1000 Hz and pure-tone thresholds of 1000 Hz was 3.8 and 12.9 dB, and that between the ABR and pure-tone thresholds was 6.8 and 14.1 dB, respectively. The threshold patterns of 80-Hz AMFR clearly followed the corresponding audiogram patterns in all types of hearing impairment. The measurement of 80-Hz AMFR thus appears to be accurate in hearing assessment and to have good frequency specificity in children during sleep.

Adolescent↗