Search PubMed⌕ Search

Biomedical subjects

T Tanahashi

Publications and source records attributed to T Tanahashi.

At least 73 records · Page 4Linked to original sources

[Response of the cochlear nucleus neurons of the cat to tone-burst-trains].

Although both posteroventral cochlear nucleus (PVCN) and dorsal cochlear nucleus (DCN) are innervated by the descending branch of auditory nerve fibers, their intrinsic morphological organizations are so different that their physiological roles are expected to be different in signal processing. Temporal information coding of acoustic signals in the cochlear nucleus was examined by using stimuli of "tone-burst-trains (TBT)". Responses of cochlear nucleus neurons of anesthetized cats were recorded either intracellularly or extracellularly. Responses of the neurons to TBT stimuli were classified into "adaptive type" and "non-adaptive type". The "adaptive type" neurons were mainly recorded from PVCN. Responses of these neurons to TBT stimuli decayed exponentially, because of short-term adaptation, in the subsequent tone-bursts. These neurons faithfully preserve the adaptative behavior of auditory nerve fibers. On the contrary, the "non-adaptive type" neurons were mainly found in DCN. They showed variety of responses to TBT stimuli including facilitation, disinhibition and inhibition depending on duration and/or interval of tone-bursts. Our results suggest that some "non-adaptive type" neurons, showing facilitative and/or inhibitory responses to TBT stimuli, act as temporal filters that extract temporal information from acoustic signals.

Acoustic Stimulation↗

[Midazolam as a premedicant for trigeminal nerve blocks].

Although patients with trigeminal neuralgia can be treated satisfactorily with nerve blocks, the block procedure is sometimes very painful and uncomfortable for them. To investigate the efficacy and adverse effects of midazolam as a premedicant for trigeminal nerve blocks, 19 patients were randomly assigned to receive either midazolam (0.05 mg.kg-1, n = 6), midazolam (0.1 mg.kg-1, n = 7), or saline/placebo (n = 6) before the block. The patients given midazolam (0.1 mg.kg-1) had a significantly lower incidence of recalling the block procedure and had complained of less discomfort when interviewed the following day. No serious adverse effects were observed in any patient given midazolam. Midazolam can be used safely as an effective premedicant for potentially uncomfortable procedures such as trigeminal nerve blocks.

Aged↗

[Phase II study of 5'-DFUR treatment of the bladder and prostatic cancer].

Phase 2 study of 5'-DFUR in bladder and prostatic cancer was conducted at 15 collaborative institutions including Okayama University. 5'-DFUR was orally administered to patients at a daily dose of 800-1200 mg for more than 4 weeks. Forty-one patients with bladder cancer and 12 patients with prostatic cancer were evaluated. The response rate for bladder cancer was 31.7% (CR, 1 case: PR, 12 cases), against no response with prostatic cancer. Moreover, the concentration of 5-FU in bladder tumors was confirmed to be high. Adverse reactions such as diarrhea, anorexia, and nausea were observed. Thus, 5'-DFUR seems to be useful for the treatment of bladder cancer.

Administration, Oral↗

Radioimmunoassay for the quantitative determination of galanthamine.

A radioimmunoassay for the quantitation of pmol amounts of the therapeutically important Amaryllidaceae alkaloid, galanthamine, has been developed. The antiserum was raised against a conjugate of galanthamine-2-O-hemisuccinate-bovine serum albumin. The measuring range of the assay extends from 0.5 to 100 ng of galanthamine, and as little as 3.5 pmol may be detected. The antiserum is highly specific for galanthamine, showing practically no cross reactivity with different representatives of the most frequently occurring types of alkaloidal structures in Amaryllidaceae. This assay enables a rapid, sensitive and precise quantitation of galanthamine in unpurified plant extracts. The galanthamine concentration in bulbs of several Leucojum aestivum plants and the distribution of galanthamine in some Amaryllidaceae genera of South African origin have been investigated. Preliminary experiments indicate that the galanthamine-specific radioimmunoassay can be a useful tool in medicinal plant breeding as well as in tissue and cell culture studies.

Animals↗

[Response of cochlear nucleus neurons of the cat to complex tone].

The response of the cochlear nucleus neurons in the anesthetized cat to complex tones has been studied for understanding the processing of tonal informations in that nucleus. Forty-eight cats were used in this study and data was obtained from 148 neurons with microelectrode technique. Two kinds of stimulus tones were applied and each of them consisted of pure tones (f1, f2, f3) and three complex tones (f1 + f2, f1 + f3, f2 + f3). The first group was composed of three pure tones of 670, 1250, 2400Hz and the second group was composed of those of 350, 500, 1100Hz, respectively. In 50 out of 148 cochlear nucleus neurons, we obtained some responses to complex tones. Response patterns to complex tones in 34 out of 50 cochlear nucleus neurons were similar to response patterns which had been obtained from auditory nerve. In 16 out of 50 neurons, however, the PST histogram pattern which had been obtained by complex tone stimuli did not show the same pattern as that of pure tone stimuli. For example, in same neuron, sustained type and pauser type responses had obtained by pure tones stimulus, but chopper type response had obtain by complex tone stimuli. And some neural activities were facilitated by the complex tones. From these results it can be speculated that the certain functions of the processing of the complex tones will be exist in the cochlear nucleus.

Acoustic Stimulation↗

[Studies on relationship between histology, tumor markers (prostatic acid phosphatase.prostate specific antigen.gamma-seminoprotein.leu-7) and clinical course in prostate cancer].

We are interested in the therapeutic response to chemotherapy and radiotherapy of relapsed prostate cancer. In 9 cases of prostate cancer treated by endocrine therapy, tumor markers (PAP.PA.gamma-Sm.Leu-7) and cell types at the start of endocrine therapy and that taken at a hormone independent point were compared between prostatic tissue obtained. All cases had a period of response to endocrine therapy, but subsequently relapsed. The results were divided into the following 3 groups: Group I (changed cell type.decreased positive rate of markers) had the shortest response duration to endocrine therapy and there was no response to chemotherapy; Group II (unchanged cell type.decreased positive rate of markers) had a long response duration and slow progression under endocrine therapy; Group III (unchanged cell type.unchanged positive rate of markers) was chemo- or radiotherapy sensitive during post-endocrine therapy relapse. These results suggest that this is an effective method which dictated the choice of treatment method and allowed an approximate prognosis for relapsed prostate cancer previously treated by endocrine therapy.

Acid Phosphatase↗

[Selective percutaneous thermocoagulation of the glossopharyngeal nerve in intractable glossopharyngeal neuralgia].

Percutaneous radiofrequency thermocoagulation of glossopharyngeal nerve at the jugular foramen was employed for the treatment of intractable glossopharyngeal neuralgia in three cases, one with essential and two with symptomatic pain from malignant tumor of the oropharyngeal area. Under radiological control, the thermocoagulation electrode was inserted through the lateral cervical route, and the electrode reached the jugular foramen with the tip toward the pars nervosa. The correct position of the electrode was confirmed by radiography and by electrophysiological stimulation test. Once the electrode was properly positioned, lesion was made with temperature of 60 degrees C to 70 degrees C for 1 approximately 2 minutes. Surgical results were satisfactory and no neurological and cardiovascular complications were noted. Percutaneous radiofrequency thermocoagulation of glossopharyngeal nerve is thought to be very useful for the treatment of intractable glossopharyngeal neuralgia.

Adult↗

[Clinical and endocrinological studies of the luteinizing hormone-releasing hormone analogue therapy in prostatic cancer patients].

A luteinizing hormone-releasing hormone (LH-RH) analogue was administered for 3 to 32 months to 15 prostatic cancer patients in stage B-D (B:3, C:8, D:4). Intratesticular, intratubular and prostatic androgen levels were measured by radioimmunoassay before and after LH-RH analogue therapy. The measurement of serum prostatic acid phosphatase (PAP) and prostatic specific antigen (PA) levels was also conducted. Thereafter, we assessed the effect of the LH-RH analogue on androgen levels and the relation of prostatic tissue 5 alpha-dihydrotestosterone (DHT) level to the clinical response. The results were as follows: 1) Johnsen's mean germinal epithelium count was significantly decreased from 7.7 +/- 2.1 (mean +/- S.D.) to 4.3 +/- 2.3, and the wall thickness of seminiferous tubules was increased from 5.93 +/- 1.31 to 11.9 +/- 3.64 microns. 2) Plasma testosterone (T), intratesticular and intratubular androgen levels were significantly decreased (plasma T: from 4.40 +/- 1.84 to 0.61 +/- 0.32 ng/ml, intratesticular T: from 335.3 +/- 170.3 to 4.6 +/- 3.8 ng/g.t.w., DHT: from 25.3 +/- 11.7 to 3.7 +/- 2.7 ng/g.t.w., intratubular T: from 50.8 +/- 36.6 to 0.10 +/- 0.99 ng/g.t.w. and DHT: 7.54 +/- 3.20 to 0.63 +/- 0.90 ng/g.t.w.). 3) Crude nuclear DHT levels in prostatic tissue fell from 15.3 +/- 9.3 (N = 8) to 0.37 +/- 0.54 pg/mg protein (N = 3) and the level was non-detectable in 5 of 8 cases. 4) Complete remission was achieved in 1 patient, partial response in 5, objective stable in 8, and objective progression in 1 patient, according to Shimazaki's criteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗

[A case of small cell carcinoma of the urinary bladder].

A case of small cell carcinoma with a high serum alpha-fetoprotein level of the urinary bladder is reported. Histologically, in addition to the small cell carcinoma, there were small areas of atypical carcinoids and larger epithelial cells. Immunohistochemically, the small cell carcinoma and the atypical carcinoids showed positivity for neuron-specific enolase, chromogranin, and vimentin. On the other hand, the larger epithelial cells showed positivity for alpha-fetoprotein, keratin, and carcinoembryonic antigen. Electron microscopically, a few neurosecretory granules were noted in the cytoplasm of the small cell carcinoma. After a total cystectomy, the serum alpha-fetoprotein level decreased to within a normal range. Postmortem examination of recurrent tumorous masses revealed only features of the small cell carcinoma. This case supports a theory that a small cell carcinoma of the urinary bladder develops from multipotential epithelial cells.

Aged↗

[Kappa-type opioid receptor in human placental membrane].

Since many opioid receptor preparations are heterogeneous systems containing multiple types of receptor, characterization of each type of the receptor is influenced by contamination with other types of receptor. Demonstrating kappa receptor proved more difficult owing to the ability of kappa ligands to interact with a number of receptor classes and to the lack of the homogeneous preparation. It has been reported that kappa ligands selectively bind to human placental membrane. To establish homogeneous kappa receptor preparation, the kappa binding to human placenta was characterized. The portion which was predominantly villus tissue was removed from freshly collected placenta, and the P3-membrane fraction was prepared. Kappa opioid agonist, such as 3H-Dynorphin A, 3H-ethylketocyclazocine and 3H-U-69593, bound to the human placental membrane fraction in a manner of single class of binding site (Bmax: approximately 40 fmol.mg-1 protein). In contrast, 3H-dihydromorphine, 3H-DAGO (mu agonist), 3H-DADLE (delta agonist) or 3H-SKF-10047 (sigma agonist) showed no binding activity. The specific binding of 3H-diprenorphine was displaced only by kappa-selective ligand (U-50488H, dynorphin, butorphanol). These results suggest that opioid binding in human placental membrane is specific for kappa opioid.

Humans↗

[A case report of reflex sympathetic dystrophy treated with nifedipine].

Reflex sympathetic dystrophy (RSD) refers to a symptom complex observed after nerve injury and consists primarily of severe burning pain associated with sensory, vasomotor and trophic phenomena. A 54-year-old male had undergone nephrectomy. At surgery left XIth intercostal nerve had been injured by cautery. After a few weeks following surgery, the patient developed progressive deep burning pain, stabbing sensation and dysesthesia in the left abdominal region. Analgesics and narcotics were ineffective. We diagnosed his case as RSD. He received nifedipine 10mg sublingually. Pain relief was obtained within 10min and lasted for 6hs. Consequently, nifedipine therapy was started at a daily dose of 30 to 60mg. His symptoms were markedly improved within 4 weeks. After 3 months his pain resolved. At the present, some pain often returns, but nifedipine is effective. Nifedipine may be useful as a drug for the management of reflex sympathetic dystrophy.

Humans↗

[A case of vesical carcinoma with sarcomatous changes--immunohistochemical and electron microscopic observations].

The immunohistochemical and electron microscopic characteristics of a vesical carcinoma with a sarcomatous change in a 90-year-old man are described. Keratin was strongly positive in the carcinomatous region and was also identified in the sarcomatous region. CEA was present only in the carcinomatous region. Both the carcinomatous and sarcomatous regions were negative for S 100 protein, myoglobin, lysozyme, and desmin. Electron microscopically, a few tumor cells with tonofilaments were observed in the sarcomatous region. Many tumor cells in the sarcomatous region had no characteristic structures suggestive of epithelial or mesenchymal origin. However, transitional types of tumor cells, between the epithelial cells and the cells with neither epithelial nor mesenchymal differentiation, were noticed. Therefore, this suggested that the sarcomatous region was a site of immature epithelial cell proliferation.

Aged↗

A calmodulin antagonist (W-7) and a protein kinase C inhibitor (H-7) have no effect on atrial natriuretic peptide release induced by atrial stretch.

The role of intracellular signals in the regulation of atrial natriuretic peptide (ANP) release was investigated using isolated rat left atria. Dibutyryl cyclic AMP and dibutyryl cyclic GMP had no effect on ANP release. Arginine vasopressin and phenylephrine, both of which activate the polyphosphoinositide system and consequently both the diacylglycerol-protein kinase C system and the Ca2+-Ca2+ receptor system, stimulated ANP release dose-dependently. The ANP release stimulated by phenylephrine was inhibited by N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), a calmodulin antagonist, and 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), a protein kinase C inhibitor. Atrial stretch stimulated ANP release, but the release was not inhibited by W-7 or H-7. These results suggest that the mechanism responsible for phenylephrine-induced ANP release differs from that for stretch-induced ANP release.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

Adenofibroma of the rete testis. A case report with electron microscopy findings.

The light and electron microscopic characteristics of an adenofibroma of the rete testis in a 51-year-old man are described. The tumor was 5.5 cm in greatest diameter and situated in the anterior superior portion of the right testis. It was composed mainly of mesenchymal and secondary epithelial proliferation. Long slit-like spaces and short tubules lined by a layer of epithelial cells were seen in the mesenchymal tissue. The epithelium was histochemically and ultrastructurally similar to that of the rete testis, and the tumor was considered to be of rete testis origin.

Adenofibroma↗

[An autopsy case of malignant retroperitoneal paraganglioma].

A case of an extra-adrenal malignant paraganglioma of the retroperitoneum is reported. A 33-year-old woman with a complaint of a dull pain in the right thigh was admitted. A CT scan revealed a large retroperitoneal mass situated between the right kidney and the aorta. A biopsied specimen of the right femur uncovered a metastatic focus of a paraganglioma. Subsequent chemotherapy and irradiation ultimately proved ineffective, and the patient died at the age of 37. Autopsy revealed a retroperitoneal mass 11 X 9 X 4 cm, and its metastatic foci in the vertebrae, ribs, sternum, and liver. Six cases of extra-adrenal malignant paragangliomas of the retroperitoneum that have been reported in Japan also are briefly reviewed.

Adult↗

[A case of small cell carcinoma of the prostate].

A case of a small cell carcinoma of the prostate that occurred in a 68-year-old man is reported. Needle biopsy of the prostate showed an adenocarcinoma. A second biopsy revealed both an adenocarcinoma and a small cell carcinoma. A subsequent third biopsy revealed only a small cell carcinoma, and the patient died of respiratory failure 26 months after the initial presentation. An autopsy revealed the tumor that had replaced the prostate extended into the bladder and rectum. Widespread metastatic foci, showing a histologic pattern of solely a small cell carcinoma, were present in various organs. The adenocarcinoma component was seen restricted to the prostatic region. Immunoperoxidase staining for prostate-specific antigen, prostate-specific acid phosphatase, gamma-seminoprotein, and leu-7 showed positivity only in the adenocarcinoma, whereas neuron-specific enolase was positive only in the small cell carcinoma.

Adenocarcinoma↗