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Biomedical subjects

I Takeyama

Publications and source records attributed to I Takeyama.

At least 37 records · Page 2Linked to original sources
PubMed1993

Role of the dorsolateral pontine nucleus in two components of optokinetic nystagmus (OKN).

The anatomical features of the dorsolateral pontine nucleus (DLPN) implicate a role of the nucleus in the generation of smooth-pursuit eye movements. The DLPN receives convergent inputs from a variety of parieto-occipital cortical visual areas and projects its fibers to the flocculus and vermal lobules VI and VII. In addition to cortical afferent fibers, the DLPN receives descending fibers from the nucleus of the optic tract which is indicated as the first subcortical optokinetic nystagmus (OKN) relay. DLPN units respond not only to a discrete visual spot but also to large-field OKN stimuli. On the basis of the above anatomical and physiological features, OKN was investigated in 2 alert monkeys whose DLPN was physiologically identified and into which reversible lidocaine was injected. The present findings showed that a rapid rise in OKN velocity was reduced in both monkeys, whose lesions included the uppermost rostral part of the nucleus in the one monkey and the entire nucleus in the other, whereas optokinetic after-nystagmus velocity was affected only in the latter. Taken together with physiological data, the DLPN possibly shares the domain of low selectivity speed selection in OKN and does not play a main role in the generation of OKN.

Animals↗
PubMed1993

Immunohistochemical study and an electron microscopic observation of the nucleus of the optic tract in the rat.

In the present study, gamma aminobutyric acid (GABA)-positive cells and terminals were detected in the nucleus of the optic tract (NOT) in the rat. However, GABA-positive cells in the NOT receiving projections directly from retinal ganglion cells could not be identified. To determine the role of GABA in the projection from the retinal ganglion cells to the NOT, we used electron microscopy to observe this nucleus of a rat in which one eyeball had been removed. In the nerve synapse binding region of the NOT on the side opposite to the enucleated eyeball, the symmetrical and asymmetrical types were recognized; the ratio between the two was the same as before the eyeball was enucleated. From these results, we conclude that the inhibitory axon terminals in the NOT do not have GABA activity. The GABA-positive cells seem to act indirectly as intrinsic interneurons, when processing or transmitting the information from the retina to the inferior olivary nucleus.

Animals↗
PubMed1993

[Expression of human papillomavirus (HPV) gene in HPV-positive laryngeal tumors and activity of the HPV long control region in cultured normal laryngeal epithelial cells].

Expression of the human papillomavirus (HPV) gene was examined in HPV-positive laryngeal tumors. Moreover, the activity of the HPV long control region (LCR) was tested in cultured laryngeal epithelial cells. HPV-11 early genes were heterogeneously expressed in adult laryngeal papillomas. We found one laryngeal carcinoma case in whom the HPV-16 transforming genes, E6 and E7, were expressed. Both HPV-11 and -16 LCRs were active in cultured laryngeal epithelial cells from vocal cords. These results suggest that laryngeal epithelial and tumor cells are target cells for HPV gene expression.

Adult↗
PubMed1992

Immunohistochemical study of c-erbB-2 oncoprotein overexpression in human major salivary gland carcinoma: an indicator of aggressiveness.

In order to analyze the correlation between immunohistochemical positivity for c-erbB-2 oncoprotein and prognosis in patients with malignant salivary gland tumors, 59 cases of malignant tumors of the major salivary glands, including 35 parotid gland, 20 submaxillary gland and 4 sublingual gland tumors, were studied immunohistochemically using a polyclonal antibody against c-erbB-2 oncoprotein. Positive staining was observed in 13 (22%) of the 59 cases. Interestingly, positive results were obtained only in adenocarcinoma (6/20) and carcinoma in pleomorphic adenoma (7/15), and not in any other histological types such as adenoid cystic carcinoma, mucoepidermoid tumor, and squamous cell carcinoma. There was no correlation between the degree of differentiation of adenocarcinoma and c-erbB-2 positivity. Since the carcinoma in pleomorphic adenoma positive for c-erbB-2 oncoprotein was adenocarcinoma, adenocarcinoma and adenocarcinoma in pleomorphic adenoma were placed together (n = 33), and the presence or absence of c-erbB-2 oncoprotein in this group was examined for correlation with patients' survival and other clinicopathological features, including clinical stage, tumor size, surgical margins, and lymph node status. The c-erbB-2-positive tumors tended to be more advanced and larger than negative tumors. Similarly, c-erbB-2-positive tumors were difficult to resect completely, were associated with lymph node metastasis more frequently, and showed lower disease-free survival than negative cases (P less than .05). We conclude that immunohistochemical positivity for c-erbB-2 is an indicator of aggressiveness in both adenocarcinoma and adenocarcinoma in pleomorphic adenoma of the major salivary glands.

Adenocarcinoma↗
PubMed1992

Retinal ganglion cells related to optokinetic nystagmus in the rat.

The nucleus of the optic tract (NOT) in the pretectum is the visuo-motor relay between the retina and preoculomotor structure in the pathway conveying signals responsible for optokinetic nystagmus (OKN) in both afoveate and foveate animals. Unilateral lesions of the NOT abolish OKN toward the side ipsilateral to the lesion. However, what parts of the retina and what kinds of retinal ganglion cells project their fibers into the NOT are still unknown. To examine this, horseradish peroxidase conjugated with wheatgerm agglutinin was injected into the NOT of the rat. Labeled retinal ganglion cells were diffusely documented in the contralateral side, whereas those situated only in the lower temporal crescent, were found in the ipsilateral side. Ganglion cells dominated in the range of small cells, i.e., W cells. Therefore, ganglion cells responsible for OKN are believed to be related to W cells. However, medium-sized and large cells were definitely labeled in the rat, suggesting possible participation of these cells in OKN.

Animals↗
PubMed1992

[Biopsy of head and neck lesions with a Biopty biopsy instrument].

Recently, "Biopty-Gun" technique has been introduced as a new biopsy technique specially in urological field. We applied it to obtain histopathological specimens of head and neck lesions. 25 specimens were taken with 18-gauge needle, using ultrasonic guidance in cases where the targets were very close to arteries or very small or cystic lesions. All these 25 specimens could be obtained without any complication such as crushing of tissue and they were all sufficiently clear and high-quality specimens. In 23 of these 25 specimens, exact histopathological diagnosis could be made. "Biopty-Gun" minimizing possible movement of tissue which may often occur with the conventional biopsy technique, permitted obtaining tissue specimens without crushing or damaging cells of tissue to be sampled, and it was concluded to be a highly safe and useful biopsy procedure.

Adolescent↗
PubMed1991

Long-term follow-up of electrocochleogram in Ménière's disease.

Serial electrochochleogram (ECochG) recordings were obtained over a long time span from 24 patients with Ménière's disease showing dominant negative SP. The long-term fluctuation of responses (especially SP) was evaluated. Dominant -SP or abnormally increased SP/AP ratio has been unchanged over long periods in most operated or nonoperated patients. It is assumed that the generation of -SP dominance may chiefly result from the malfunction of hair cells, which may be caused by abnormal changes in inner ear fluids associated with endolymphatic hydrops or by other unknown disturbances in the cochlea. The mechanical factor of basilar membrane displacement can hardly be considered as a main cause of SP abnormality.

Audiometry, Evoked Response↗
PubMed1991

Detection of Epstein-Barr virus DNA in formalin-fixed paraffin-embedded tissue of nasopharyngeal carcinoma using polymerase chain reaction and in situ hybridization.

The polymerase chain reaction method for amplification of DNA in formalin-fixed, paraffin-embedded tissue sections was used to detect Epstein-Barr virus DNA in nasopharyngeal carcinomas from Japanese patients. Thirty-one cases of nasopharyngeal carcinoma and 8 cases of lymph node metastasis of nasopharyngeal carcinoma were studied. Detection rates of Epstein-Barr virus in various types of nasopharyngeal carcinoma according to the World Health Organization classification were as follows: 10 of 10 undifferentiated carcinomas, 8 of 13 nonkeratinizing carcinomas, and 5 of 7 keratinizing carcinomas. Eight lymph node metastases, for which the primary was positive for Epstein-Barr virus, also contained Epstein-Barr virus DNA. By in situ hybridization using a biotinylated Epstein-Barr virus probe, it was clearly demonstrated that Epstein-Barr virus DNA was localized in the nuclei of the neoplastic cells. The clinical features of nasopharyngeal carcinoma with or without Epstein-Barr virus were not different. These results demonstrate that nasopharyngeal carcinoma in Japanese patients is closely associated with Epstein-Barr virus infection, similar to nasopharyngeal carcinoma of other endemic and nonendemic areas.

Carcinoma↗
PubMed1991

Vestibulo-thalamic neurons give off descending axons to the spinal cord.

Vestibulo-thalamic (VT) neurons were physiologically studied in the anesthetized cat. Forty-seven VT neurons were recorded extracellularly. More than half of the VT neurons responded monosynaptically to vestibular nerve stimulation while the others responded polysynaptically. They were activated antidromically from one or two sites in the VPL. VPM, VL, VM, SG, and PO of the contralateral thalamus. Four fifths of the VT neurons were activated from the C1 segment of the spinal cord. Half of them were also activated from the C4 segment, but none were activated from the L5 segment. It is suggested that most VT neurons project descending axons to the cervical spinal cord. Axonal branching was shown by means of systematic microstimulation in the thalamus and the ventral horn in the C1 segment. The VT neurons were mainly located in the descending vestibular nucleus.

Animals↗
PubMed1991

Retinal ganglion cells projecting to the nucleus of the optic tract in the rat.

The nucleus of the optic tract (NOT) has been identified as the link between the retina and the premotor nuclei in the pathway mediating the optokinetic nystagmus (OKN). However, it is still unclear from what parts of the retina and what kinds of retinal ganglion cells the NOT receives visual inputs related to OKN. In the present study, horseradish peroxidase conjugated with wheatgerm agglutinin (WGA-HRP) was injected into the NOT of hooded rats to investigate retrogradely labeled cells in the retina. A solution of WGA-HRP was injected into the NOT through a glass micropipette. Injection sites of the brain and the retina were processed by tetramethyl benzidine protocol and Hanker-Yates method. The labeled cells were observed in the whole area of the retina contralateral to the injection site, while located only in the ventral region of the retina ipsilateral to the injection site. In the retina contralateral to the injection site, a large number of small-sized cells and a few medium-sized cells were labeled diffusely except for surroundings of the optic disc, whereas in the ipsilateral retina there were small and medium-sized cells in the ventral part, being about 8 times greater than those in the contralateral retina. The present study indicates that visual signals responsible for OKN are conducted through the retinal ganglion cells mainly contralaterally, and only from the ventral area of the retina ipsilateral to the injection site.

Animals↗
PubMed1991

EOG findings in patients with lesions in cerebellar peduncles.

EOG tests were performed in patients with lesions in either the superior or the middle cerebellar peduncle, because these patients showed cerebellar signs and symptoms and were difficult to distinguish from patients with cerebellar lesions symptomatically. EOGs of these patients showed a predominant decrease of pursuit gains and OKN velocity gains toward the lesioned side, whereas the percent reduction of fixation-suppression of caloric nystagmus decreased predominantly toward the side contralateral to the lesioned side, regardless of whether lesions were located either in the superior or the middle cerebellar peduncle. The present EOGs are best interpreted as a corresponding to a deficit of the neuronal events of the flocculus in the monkey and are solely ascribed to lesions in the cerebellar peduncles, because even well-defined cerebellar lesions on one side showed bilateral impairments of these visually induced eye movements.

Cerebellar Diseases↗
PubMed1990

Tracheostomy--the horizontal tracheal incision.

The complication rate after emergency tracheostomy is two to five times greater than after elective procedures. One of the main causes of the high risk of complications in emergency tracheostomy appears to be the amount of time required to open the trachea. Therefore, simple and fast procedures are mandatory. We have developed a new procedure as follows: A horizontal skin incision is performed. Strap muscles are dissected and retracted laterally. A transverse cut between tracheal rings below the thyroid isthmus is performed up to membranous portion of the trachea. The cut ends of the trachea remain open naturally because of the elasticity of the trachea. Skin and tracheal cut-ends are then joined by interrupted sutures. We have used this procedure during the past three years and have not experienced any major complications. This demonstrates the clear advantage and the more physiological nature of the procedure over various other incisions of the tracheal wall.

Adult↗
PubMed1990

[Investigation of UFT and radiation combination therapy of head and neck cancer--mainly in laryngeal cancer].

We studied the effects of simultaneous combination therapy with UFT and radiation for 69 head and neck cases with the same protocol in 6 universities in Kanagawa. Completed cases (cases in which therapeutic effects could be evaluated) totaled 67 patients who could receive more than 40 Gy as a given radiation dose and more than 8.4 g as a total UFT dose. Responder rate at 90th day after completion of radiation in 67 completed cases (CR 57 cases + PR 6 cases/67 cases) was as favorable as 94%. A comparison between 52 cases of the most frequent laryngeal cancer and historical control 113 cases received single radiation therapy by means of Kaplan-Meier method resulted significantly (P less than 0.05) favorable in UFT combination group as for disease free rate in all cases, disease free rate in Stage IV cases, disease free rate in glottic cancer, and survival rate and disease free rate in supraglottic cancer. No severe adverse reactions were observed in all cases. This combination therapy with radiation and UFT was judged effective for head and neck cancer, especially laryngeal cancer.

Adult↗
PubMed1989

Clinical significance of SP/AP ratio in inner ear diseases.

Electrocochleogram was recorded from 28 ears affected by Ménière's disease , 27 ears affected by sensorineural hearing loss resulting from hair cell damage and 22 normal ears as controls in response to tone bursts in order to evaluate diagnostic significance of the summating potential/action potential (SP/AP) ratio and the SP amplitude. The fundamental aspects of the SP/AP ratio were studied in relation to frequency, intensity and rate of tone burst stimuli. It was concluded from present results that the SP/AP ratio can be a useful indicator to detect -SP dominance, while the SP amplitude can be an indicator to detect cell damage in inner ear diseases.

Adult↗
PubMed1988

Distribution of retinal ganglion cells projecting into the nucleus of the optic tract in rat.

The present study indicates that visual signals responsible for OKN are conducted through the retinal ganglion cells mainly contralaterally, and only in the ventral region of the retina ipsilateral to the injection site. The retinal ganglion cells projecting into the NOT ipsilateral to the injection site were identified as small- and medium-sized cells in the rat. The density of the ventral ganglion cells of the retina contralateral to the injection site was lower than that in any other regions of the retina except for the dorsal region of the retina, and the density of the ventral ganglion cells ipsilateral to the injection site was about 4 times greater than that on the contralateral side. This finding requires physiological investigation in the future.

Animals↗
PubMed1985

[Chemotherapy with FT-207 suppository (Futraful Supo) in head and neck cancer--cooperative studies by six medical schools in Kanagawa Prefecture].

Chemotherapy with FT-207 suppository (Futraful supo) for head and neck cancer was studied by Six Medical Schools in Kanagawa Prefecture, and its effectiveness and side effects were examined. Seventy-five cases were treated with this drug. However, thirty-four cases were used for the final evaluation, with regard to the given dose etc. Generally, the effectiveness rate was 23.5%. Thyroid cancer, nasal cancer and paranasal sinus cancer gave the best results. All four cases of adenocarcinoma showed an effect. One case, who was given a higher dose, showed an increased effect. Also, cases which has not been treated with any other therapeutic procedure previously, showed a significant effectiveness rate. Side effects were observed in 45.2% of cases. These were largely appetite loss and so on, which concerned the digestive system. On the whole, it has been proved that FT-207 suppository (Futraful Supo) is useful as an induction chemotherapeutic drug for head and neck cancer.

Adult↗