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Biomedical subjects

I Nagayama

Publications and source records attributed to I Nagayama.

At least 19 recordsLinked to original sources
PubMed1996

Prognostic value of EGFR and TGF-alpha in early laryngeal cancer treated with radiotherapy.

The purpose of this study was to determine the overexpression of both epidermal growth factor receptor (EGFR) and transforming growth factor-alpha (TGF-alpha) (a ligand of EGFR) in early laryngeal squamous cell carcinoma. In addition, we attempted to evaluate the prognostic values of our findings. Expression of EGFR and TGF-alpha in tumor tissue was examined immunohistochemically in 68 patients who had been treated with radiotherapy for early laryngeal cancer. Overexpression of the two factors was noted in 42.6% and 55.9%, respectively. No significant differences due to age, tumor size, and location or grade of cancer tissues were seen. Higher survival rates, found in patients with EGFR (-) and TGF-alpha (-) tumors as compared with those with EGFR (+) and TGF-alpha (+) (97.4%, 100% and 86.2%, 86.8%, respectively), were not statistically significant. The recurrence rates were similar between EGFR (+) and EGFR (-) (37.9% and 35.9%, respectively). However, the recurrence rate in patients with TGF-alpha (+) was significantly higher (57.9%) than in those with TGF-alpha (-) (10%; P<.01). Therefore overexpression of TGF-alpha may be an important indicator for recurrence in patients with early laryngeal squamous cell carcinoma treated by irradiation.

Adult↗
PubMed1995

Expression of EGF, EGFR and PCNA in laryngeal lesions.

The expression of EGF/EGFR in 47 laryngeal surgical specimens from 44 patients was examined. PCNA analysis as an index of proliferating cells was also performed in 32 cases of laryngeal cancer, six cases of pre-cancerous lesions and nine cases of normal laryngeal mucosa. EGFR failed to show a significant correlation with tumour behaviour, but EGF expression was statistically significantly higher in malignant (SCC) than in non-malignant tissues (pre-cancerous and normal tissues) (p < 0.006), and PCNA also showed a statistically significant difference (p < 0.016) between the two. In malignant tissues when EGF/EGFR in 'double-positive' and 'double-negative' cases was compared, a statistically significant difference in PCNA was found (p < 0.029); but this was not seen in non-malignant tissues. Our results support the hypothesis that an autocrime mechanism exists in laryngeal cancer and in this mechanism EGF may play an important role in tumour progression, especially when EGFR is overexpressed.

Adult↗
PubMed1995

Development of high frequency vestibulo-ocular responses to active head shaking.

Computer aided active head shaking test has several advantages because it can be used clinical at frequencies higher than 2 Hz. In this study, VOR gain and phase were examined over age. For this experiment, we designed an original measurement system composed of EOG, an angular velocity sensor and a microcomputer. VOR gain was expressed by transfer function. Forty normal subjects ranging from 10 to 75 were examined for high frequency VOR responses to active head shaking. VOR gain at frequencies higher than 2 Hz attained the same value as that seen in children below the age of 10 years. The VOR gain was nearly 1 within 2 Hz, decreasing with frequencies above 4 Hz. The effect of aging was shown at frequencies of more than 4 Hz, and appeared in patients above 50 years of age. No obvious phase lag was observed within 5 Hz.

Adolescent↗
PubMed1994

Importance of pre-operative recognition of the nonrecurrent laryngeal nerve.

The nonrecurrent laryngeal nerve is vulnerable during thyroid surgery. Pre-operative recognition of this nerve allows surgeons to avoid injuring the nerve. This anomaly depends upon the aortic arch anomaly and, therefore, in some cases, surgeons are able to predict the presence of this nerve pre-operatively by chest X-ray or barium swallow. Two patients with nonrecurrent laryngeal nerve are reported, one of whom, a 48-year-old man, had an abnormal shadow of the aortic arch, which led to confirmation of a right aberrant subclavian artery. Barium swallow plays a decisive role in the diagnosis of nonrecurrent laryngeal nerve, and this test is mandatory in patients who complain of difficulty in swallowing.

Abnormalities, Multiple↗
PubMed1993

Malignant schwannoma arising in a paranasal sinus.

A case of malignant schwannoma arising in a paranasal sinus is reported. In this case, histological hallmarks were lost because of the poorly differentiated nature of the tumour. Immunohistological techniques were applied to the diagnosis, confirming the neural origin of this tumour. Malignant schwannoma is a relatively rare disease in the nasal cavity and paranasal sinuses. For the treatment of this tumour, wide resection is recommended. In this patient, radical resection of the maxilla with orbital and ethmoid exenteration was performed. The patient recovered uneventfully with no evidence of disease three years after surgery.

Ethmoid Sinus↗
PubMed1993

Inhibition of the ATP-sensitive potassium channel by class I antiarrhythmic agent, cibenzoline, in rat pancreatic beta-cells.

1. Cibenzoline, a class I antiarrhythmic agent, was investigated for its effect on the ATP-sensitive K+ channel of pancreatic beta-cells by the patch clamp technique. 2. In perforated patch clamp experiments, cibenzoline depolarized the membrane of single beta-cells and thereafter, caused firing of action potentials in the presence of 2.8 mM glucose. 3. Cibenzoline inhibited the activity of the ATP-sensitive K+ channel in cell-attached recordings in the presence of 2.8 mM glucose and evoked repetitive fluctuations of the baseline current, apparently reflecting the action potentials of the beta-cell. 4. In whole-cell clamp experiments, time-independent outward current was induced by depleting cytoplasmic ATP with 0.1 mM ATP and 0.1 mM ADP in the solution contained in the pipette. The outward current was inhibited by cibenzoline in a dose-dependent manner in the concentration range of 1 microM to 100 microM and half maximum inhibition occurred at 1.5 microM. 5. Cibenzoline blocked substantially the ATP-sensitive K+ channel current when applied at the inner side of the membrane in isolated inside-out membrane patches. 6. It is concluded that cibenzoline blocks the ATP-sensitive K+ channel of pancreatic beta-cells and, thereby, stimulates insulin secretion at sub-stimulatory levels of glucose.

Action Potentials↗
PubMed1993

Subject-based reference values in thyroid function tests.

To evaluate the diagnostic value of subject-based reference values in thyroid function tests, we compared intra-individual and inter-individual variation. Five specimens were collected over a period of 2 weeks from each of 47 normal subjects, 29 women and 18 men, aged 20-47 yrs. T4, FT4, T3, and FT3 were assayed by RIA, and TSH by a sensitive immunoradiometric assay. One-way ANOVA for each test was statistically significant for a main subject effect, indicating that the subjects differed in their personal mean values for the thyroid function tests (T4, P < 0.01; FT4, P < 0.05; T3, P < 0.01; FT3, P < 0.05; TSH, P < 0.01). The ratio value (intra- over inter-individual variation) was T4, 0.41; FT4, 0.60; T3, 0.53; FT3, 0.63; TSH 0.36. The data indicate that conventional reference values are insensitive when compared to subject-based reference intervals in assessing the thyroid status of a given subject. Reactivity of the thyroid to the stimulation of endogenous TSH was assessed by the ratio delta FT 3/delta TSH in TRH stimulation tests. A positive correlation between basal FT3 and delta FT3/delta TSH (r = 0.566, P < 0.05) indicates that the thyroid with higher reactivity to TSH secretes more daily thyroid hormone. Negative correlation between basal TSH and delta FT3/delta TSH (r = -0.536, P < 0.05) means that a subject with lower reactivity of the thyroid needs a higher basal TSH level to compensate. The thyroid reactivity to TSH may be an important determinant for the individuality of the pituitary-thyroid axis.

Adult↗
PubMed1992

Intratemporal facial nerve neurinoma without facial paralysis.

A 38-year-old man was referred by his general practitioner to our department on 28 October 1991, with a 2-week history of vertigo. A left aural polyp was identified. The audiogram showed a moderate conductive loss on the left side. Computed tomography (CT) and magnetic resonance imaging (MRI) confirmed the presence of the expanding lesion in the descending portion of the facial nerve. However, there was no seventh nerve paresis. At operation, the neurinoma (Schwannoma) filled the middle ear cleft and extended from the genu to the stylomastoid foramen. The floor of the middle ear had been eroded, exposing the jugular bulb. Facial nerve paresis is the usual presenting feature of a facial neurinoma. The case is presented for the reason that the absence of facial palsy as a presenting feature is rather rare, especially in the cases with large tumor and extensive bone erosion.

Adult↗
PubMed1990

[The effects of individual milk-drinking habits on nutrient intake and dietary patterns in men and women in Tottori Prefecture].

This study was performed to determine the actual conditions of milk-drinking habits in men and women, and to ascertain their effects on nutrient intake and dietary patterns. The 809 subjects were over 20 years of age and were obtained from the Tottori Prefecture Dietary Survey. The results are summarized as follows: 1. Over 40 percent of the subjects did not consume any milk during the three days of the dietary survey. Furthermore, only 38 percent of men and 46 percent of women have daily milk-drinking habits according to the results of the questionnaire. 2. Calcium and Vitamin B2 intake level and total serum cholesterol level were higher in milk-drinkers than non-milk-drinkers, in both men and women. The regression of total calcium intake from 6 groups of food was analyzed by multiple regression analysis. For both men and women who were milk-drinkers, total calcium intake was determined mostly by milk. In the case of non-milk-drinkers, total calcium intake came mostly from green vegetables for men, and other vegetables for women. 3. The ratios of both animal proteins and animal fats were higher in milk-drinkers. For women, energy percentage of fats was high and that of carbohydrates was low in milk-drinkers. The results seem to suggest that differences in dietary patterns is based on milk-drinking habits. Using the Hayashi's quantification method 3, dietary patterns were classified into two groups based on milk-drinking habits. Dietary patterns of milk-drinkers included the characteristic of eating bread, meats, and fats more frequently in men, fresh vegetables, eggs, fats and bread in women. In men, milk-drinking habits had a lesser influence on diet than in women.

Adult↗
PubMed1989

Effect of internally loaded iodide, thiocyanate, and perchlorate on sodium-dependent iodide uptake by phospholipid vesicles reconstituted with thyroid plasma membranes: iodide counterflow mediated by the iodide transport carrier.

Na+-dependent I- transport and I- counterflow were studied using phospholipid vesicles (P-vesicles) made of porcine thyroid plasma membranes and soybean phospholipid by sonication. 1) I- uptake by P-vesicles incubated in the presence of external Na+ was higher than that by P-vesicles incubated in choline+ instead of Na+. The vesicles exhibited Na+-dependent I- uptake. When P-vesicles were internally loaded with I- prior to incubation in Na+, a further increase in Na+-dependent I- uptake was observed, although the concentration of internal I- was very much higher than that outside. In the absence of external Na+, I- uptake by P-vesicles preloaded with I- was comparable to baseline uptake. 2) Na+-dependent I- uptake by P-vesicles not loaded with I- and enhanced Na+-dependent I- uptake by P-vesicles preloaded with I- were both inhibited by either of SCN- and ClO4- added outside the vesicles. 3) When P-vesicles were loaded with SCN- instead of I- and incubated in Na+, I- uptake by these vesicles was also higher than baseline Na+-dependent I- uptake. However, a ClO4- load did not result in an increase in I- uptake. These results indicate that Na+-dependent I- transport including Na+-dependent I- counterflow is specifically mediated by the thyroid I- carrier. SCN- - I- counterflow in addition to I- - I- counterflow occurs dependently on Na+, but ClO4- - I- counterflow does not.

Animals↗
PubMed1989

Preservation of sodium-dependent iodide transport activity by methimazole and mercaptoethanol in phospholipid vesicles containing thyroid plasma membranes: with evidence of difference in the action of perchlorate and thiocyanate.

The effect of methimazole (MMI) and 2-mercaptoethanol (ME) on I-transport was studied using phospholipid vesicles (P-vesicles) made from porcine thyroid plasma membranes and soybean phospholipids by sonication. 1. When buffer solutions contained either 1 mM MMI or 2 mM ME, I-uptake by P-vesicles in the presence of external Na+ was apparently higher than that in the absence of external Na+. Na+-dependent I- uptake was inhibited by both C1O4- and SCN- added externally. 2. When PM was treated with 4 mM N-ethylmaleimide prior to preparation of P-vesicles, the activity of Na+-dependent I- transport was completely lost even when P-vesicles were incubated in the presence of ME. 3. When neither MMI nor ME was added to buffers, I- uptake in the presence of external Na+ was not at all higher than that in the absence of external Na+. In these instances, however, I- uptake was much higher compared than the baseline uptake in the presence of MMI or ME, and was inhibited by external SCN- and not by C1O4- without relation to external Na+. These data indicate that MMI or ME has two distinct effects on our model system of I- transport. The one is preservation of the Na+-dependent I- transport activity by protecting a sulfhydryl group, and the other is reduction of nonspecific I- binding to P-vesicles. In addition, C1O4- is a more specific inhibitor of thyroid I- transport than SCN-, when non-specific I- oxidation is imperfectly prevented.

Animals↗
PubMed1988

Turner's syndrome: a qualitative and quantitative analysis of EEG background activity.

A qualitative and quantitative analysis was performed on the EEG background activity in 62 Danish girls and women with Turner's syndrome (30 with karyotype 45,X and 32 with other karyotypes) whose ages ranged from 6 to 47 years (87% were aged 15 years or more) and age-matched controls. The pooled data and a case-control study showed characteristic features in Turner subjects, including: (1) more rapid frequency, larger amplitude and lower amount of alpha waves, (2) higher amount of theta waves, (3) larger amplitude and higher amount of delta waves and (4) larger amplitude and higher amount of beta waves than in controls. These findings in Turner subjects were more pronounced in the left hemisphere, and more typical, except for the amplitude in alpha waves, in Turner subjects with 45,X than in those with other karyotypes. The effects of advancing age on the EEG background activity observed in controls--including more rapid frequency, decreased amplitude and amount of alpha waves, increased amount of theta and delta waves, and increased amount of beta waves, particularly after 35 years of age--were found in some Turner subjects. Hemispheric differences with higher activity (i.e. more rapid frequency, larger amplitude and higher amount of alpha waves, particularly at Fp1 and F3, and, inversely, lower amount of theta or delta waves) at P3, T3, T5 and O2 than at the opposite side were found in many Turner subjects. However, these findings were not specific for Turner subjects, since the same hemispheric differences were also observed much more markedly in controls. These topographic distributions with hemispheric differences did not provide evidence for hypofunction in the temporo-parieto-occipital tertiary area of the right hemisphere in Turner subjects, though this had been expected on the basis of neuropsychological examinations. Our findings, including transiently appearing brain hypofunction at the parietal, temporal and occipital areas, most often in the right hemisphere, indicate a relationship between the chromosomal constitution 45,X and EEG background activity. They suggest the presence of functional brain disturbance in the thalamus and in the ascending reticular activating system, which tends to disturb the thalamo-cortical circuit. Further studies, including topographic and sequential power spectrum analysis of EEG background activity, 24-h continuous EEG recording, blood flow studies (positron computerized tomography) and neuropathological examination, may be needed.

Adolescent↗
PubMed1988

[Clinical application of microfibrillar collagen hemostat (Avitene) in neurosurgical field].

Microfibrillar collagen hemostat (Avitene) is a new absorbable hemostatic agent, of which mechanisms are adhesion to the bleeding site and platelet aggregation. Histopathological examinations revealed that Avitene was biocompatible with cerebral cortex in an animal experiments. Our previous studies indicated that Avitene is very effective and safe to use as a topical hemostatic agent during craniotomy in an experimental animal. Avitene was used as a topical hemostatic agent during craniotomy in 36 patients with intracranial organic lesions. Its effectiveness of hemostasis was revealed in 95%. This agent was especially useful to prevent oozing during craniotomy. Side effect of this agent was not reported in this study. Therefore, Avitene is very effective and safe to use as a topical hemostatic agent in the neurosurgical field.

Brain↗