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Biomedical subjects

N Tanabe

Publications and source records attributed to N Tanabe.

At least 19 recordsLinked to original sources
PubMed1995

Effects of Mg2+ on the stimulation-induced changes in transmitter release at the frog neuromuscular junction.

Four components of stimulation-induced changes in neurotransmitter release are known as the synaptic plasticity at the frog neuromuscular junction. These are: fast and slow facilitation, augmentation and potentiation, classified by their decay time constants after repetitive nerve stimulation. Most experiments support the view that fast facilitation is caused by residual Ca2+. However, the causes of the other three components are not clear. We have studied electrophysiologically the effect of Mg2+ on these three components. Transmitter release was estimated by the amplitudes of endplate potential (EPP) and by the frequencies of miniature endplate potential (MEPP). The increase in the transmitter release by nerve stimulation is described as the product of four components. The magnitude of potentiation of MEPP frequencies after a tetanic nerve stimulation (100 Hz, 5000 times) increased markedly in high Mg2+ concentrations. Conversely, the magnitude of augmentation (MEPP frequencies and EPP amplitude) decreased in the higher Mg2+ Ringer solution.

Animals↗
PubMed1995

[Benefits and adverse effects of post-operative radiation therapy after radical cystectomy for patients with advanced bladder cancer].

BACKGROUND: The benefits and adverse effects of post-operative irradiation for advanced bladder cancer patients were investigated. METHODS: Ten patients with pT3b, pT4 or pN+ bladder cancer who underwent radical cystectomy at Yamanashi Medical University hospital during 7 years and 3 months from October 1983 to December 1991 received adjuvant chemotherapy and radiotherapy (Group 1). During the same period, six patients with recurrent tumor after radical cystectomy were treated by radiotherapy (Group II). Stages of the primary tumors were pT2 in 1, pT3a in 2, pT3b in 6 and pT4 in 7 cases. In addition, 10 of 16 patients (63%) had positive nodes. RESULTS: During the follow up period, seven patients died of cancer, and one died of other cause. As a result eight patients (5 in Group I, 3 in Group II) are alive. The cumulative 5-year survival rate is 50%. However, nine of the 16 patients (56%) suffered from the small bowel obstruction as an adverse effect of irradiation. Six patients required resection of the small bowel or bypass surgery. CONCLUSIONS: Radiation after radical cystectomy seemed to be effective for the local control of the tumor, but the adverse effect to the digestive system was very severe and common.

Aged↗
PubMed1995

[Cystic disease of the kidney].

The kidney is one of the most common sites of cyst. Since cystic disease of the kidney includes various disorders, it is difficult to classify the diseases systematically. It appears that the classification of the American Academy of Pediatrics is suitable for clinical side for the present. In this paper the cystic disease of the kidney is explained on actual cases. Recently, development of imaging diagnosis is contributing widely to the diagnosis of the diseases. Treatment of the diseases, however, is not established satisfactorily. It is hoped that the mechanism of occurrence of the diseases is known further and that regulation of the classification and establishment of the treatment will become available.

Aged↗
PubMed1995

[A case of idiopathic pulmonary arteritis with positive anti-myeloperoxidase antibodies].

A 38-year-old woman was referred to our hospital for severe pulmonary hypertension (pulmonary arterial pressure 63/36 mmHg). Digital subtraction angiography showed complete obstruction of the right main pulmonary artery and severe stenosis of the left main pulmonary artery. Although there were no symptoms or signs of systemic arterial lesions, the initial diagnosis was aortitis syndrome with pulmonary arterial involvement, and prednisolone therapy was started (60 mg/day). Pulmonary arterial pressure decreased to 53/12 mmHg. At a dosage of 20 mg/day, however, multiple nodular shadows were present on the X-ray film of the chest, but they disappeared after the dosage was increased. The level of anti-myeloperoxidase antibodies in her serum changed at almost the same time as multiple nodular shadows appeared on the chest X-ray film. Because anti-MPO antibodies have been never detected in patients with aortitis syndrome, polyangitis overlap syndrome was suspected. However, we found no evidence of systemic vasculitis; that is, vasculitis in other organs, including the kidney and the skin. Therefore, we made a diagnosis of idiopathic pulmonary arteritis with positive anti-MPO antibodies.

Adult↗
PubMed1992

Digital imaging techniques for dental alloy castability quantification.

In this study, mesh monitors cast from experimental compositions of a Ni-Cr-Be alloy are evaluated by the application of image analysis techniques. Castability values obtained by this method are then contrasted with those from three commonly employed manual counting procedures. While castability values obtained by all methods reflect the effect of compositional variations, a comparison of results with respect to evaluation method indicates that the image analysis technique consistently yields higher castability values, especially evident in the poorly casting groups. The apparent explanation for these observed differences is that with imaging, segments that are partially cast to varying degrees are not arbitrarily eliminated from the data, as is the usual practice in manual counting methods; therefore, castability values obtained by using the imaging technique will very closely reflect an actual alloy volume of each cast monitor.

Beryllium↗
PubMed1992

Ca(2+)-dependent and -independent components of transmitter release at the frog neuromuscular junction.

1. When a Ca2+ chelator, bis (O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), was loaded into the presynaptic nerve terminal of the frog neuromuscular junction (NMJ), facilitation, measured as an increase in endplate potential (EPP) amplitudes during a train of ten stimulations at 100 Hz, was greatly decreased within 20 min of BAPTA-AM (the acetoxymethyl ester of BAPTA) perfusion, and remained at a constant low level thereafter, suggesting that [Ca2+]i at the presynaptic nerve terminal was buffered by BAPTA. 2. Detailed examination of the two components of facilitation of EPP amplitude in the BAPTA-loaded NMJs showed that the fast component was lost almost completely, while the slow component was unaffected by loaded BAPTA. Augmentation and potentiation were also unaffected by BAPTA. 3. Under external Ca(2+)-free conditions (with 1 mM-EGTA), both augmentation and potentiation of miniature endplate potential (MEPP) frequency were clearly observed after tetanic stimulation in the normal NMJ, and were also unaffected by loaded BAPTA. 4. The above findings strongly support the residual Ca2+ hypothesis for the fast component of facilitation, and suggest that the three slower processes (the slow component of facilitation, augmentation and potentiation) occur independently of [Ca2+]i. This Ca2+ independence was supported by the fact that facilitation and potentiation have multiplicative effects on the amount of release. 5. The quantal content of the first EPP in the train remained unchanged throughout the time course of BAPTA loading for most NMJs. This suggests that [Ca2+]i immediately adjacent to Ca2+ channels at the active zone triggers transmitter release and is little affected by loaded BAPTA. 6. MEPP frequency was almost unchanged during BAPTA loading, suggesting that the basal [Ca2+]i remained unchanged close to the dissociation constant of BAPTA for Ca2+ (108 nM). 7. The slow component of facilitation had a multiplicative relationship with augmentation and potentiation, suggesting that the underlying mechanism for the slow component of facilitation differs from that for augmentation and potentiation.

Animals↗
PubMed1992

[Effects of smoking and drinking habits and vitamin A intake on serum concentrations of beta-carotene and retinol].

Serum samples from 341 males aged 10 to 59 years were obtained and stored at -40 degrees C until examined for retinol and beta-carotene concentrations by HPLC, and their relationships to smoking habit, alcohol drinking habit and vitamin A intake were studied. In univariate analysis the serum beta-carotene level was significantly lower in the smokers than in the non-smokers (smokers: 4.6 micrograms/dl, non-smokers: 7.1 micrograms/dl, p less than 0.01) and lower in the drinkers than in the non-drinkers (drinkers: 4.6 micrograms/dl, non-drinkers: 7.3 micrograms/dl, p less than 0.01). The serum retinol level was not different by smoking habit but was higher in the drinkers than in the non-drinkers (drinkers: 80.4 micrograms/dl, non-drinkers: 67.0 micrograms/dl, p less than 0.01). Serum beta-carotene was higher in the group with a greater intake of vitamin A of vegetable origin (6.1 micrograms/dl) than in the group with a smaller intake of it (4.7 micrograms/dl) (p less than 0.01), but serum retinol was not different by the amount of vitamin A intake of animal food origin. To estimate the respective effects and interactions of the above factors on serum beta-carotene and retinol levels by adjusting for the confounding effects of age, serum total cholesterol, HDL-cholesterol and triglyceride, analysis of covariance was performed. For serum beta-carotene, smoking habit (p less than 0.01), drinking habit (p less than 0.01) and the amount of vitamin A intake of vegetable food origin (p less than 0.05) had significant main effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Successful treatment of idiopathic plasmacytic lymphadenopathy with polyclonal hypergammaglobulinemia.

A 51-year-old male was admitted because of eyelid edema and anosmia, which developed in 1985. He showed bilateral cervical lymphadenopathy, with nodes larger than 2 x 2 cm, and remarkable eyelid edema. Anemia, hyperimmunoglobulinemia with hypo-albuminemia (no M-protein) and liver dysfunction were found. Bone marrow, renal function, urine analysis and LDH level were normal. Cervical lymph node biopsy showed interfollicular proliferation of plasma cells without any malignant appearance. On day 3 of oral prednisolone (PD), anosmia abruptly improved from day 7, eyelid swelling, cervical lymphadenopathy and gammopathy subsided gradually. Since PD was tapered off, no relapse has been observed thus far.

Castleman Disease↗
PubMed1992

[Relationship between signal intensity of blood flow in the pulmonary artery obtained by magnetic resonance imaging and results of right cardiac catheterization in patients with pulmonary disease].

Electrocardiogram-gated spin-echo magnetic resonance (MR) images of the chest were obtained in five normal controls and 35 patients with pulmonary disease (11 chronic obstructive pulmonary disease, 6 pulmonary thromboembolism, 5 primary pulmonary hypertension, 4 interstitial pulmonary disease, 4 pulmonary hypertension with disturbance of portal circulation, and 5 other diseases) who underwent right cardiac catheterization. In transverse images at the level of the right main pulmonary artery (rPA) and sagittal images at the level through the midsternal line and the spinal chord, the signal intensity of blood flow in the rPA was quantitatively evaluated, and the correlations with the MR signal intensity of intravascular flow and the parameters of hemodynamics were studied. In diastole MR images of both normal controls and patients mostly showed a significant signal intensity of flowing blood, but in systole some patients demonstrated significant signals and visible flow images. In systolic MR images, the mean values of hemodynamic parameters (mean pulmonary arterial pressure (mPAP), pulmonary arteriolar resistance (PAR), and cardiac index (CI)) were abnormal in patients with significant signal intensity of flow compared with those in patients without sufficient MR signal. The signal intensity was not correlated with mPAP; however, it significantly increased as PAR increased, and it increased as CI decreased both in diastole and in systole. Especially in systole, there was good correlation between the signal intensity in transverse MR images and CI (r = -0.85, P less than 0.01) and between signal intensity in sagittal MR images and PAR (r = 0.90, P less than 0.01). These results suggest that significant flow signal in the rPA in systole has pathophysiological significance, and signal intensity is considered to be significantly affected by changes of PAR and CI. The signal intensity of blood flow in the rPA on MR images can be used as an index of the severity of right heart failure associated with pulmonary disease. MR imaging is a useful modality to evaluate pulmonary circulation disturbance because of its ability to assess blood flow in the pulmonary artery noninvasively without interference from other structures such as bone and normal lung.

Adult↗
PubMed1992

[Correlation of signal intensity of blood flow in the pulmonary artery on MR images and clinical features of two cases of primary pulmonary hypertension].

ECG-gated spin-echo MR images of the chest were obtained in two patients with primary pulmonary hypertension (PPH). In transverse section at the level of the right main pulmonary artery (rPA), flow signals in the rPA were quantitatively evaluated, and the correlations with MR signal intensity of intravascular flow and data of routine clinical examinations and the severity of clinical manifestations were studied. In one case, the signal intensity of flowing blood markedly increased with exacerbation of hypoxemia and other clinical manifestations. However, in the other case with a stable course, the signal intensity of intravascular flow did not change significantly. Increase of flow signal in the rPA can reflect decrease of flow velocity that may be cause by a state of high pulmonary vascular resistance or low cardiac output. Therefore, it is suggested that MRI is a useful modality to evaluate the severity of disturbance of the pulmonary circulation in PPH.

Adolescent↗
PubMed1992

[Circadian variations of sudden death].

Characteristics of the circadian variation for sudden death (SD), were studied by analyzing summary death certificates for the period of 1984 to 1986 in Niigata prefecture. SD was defined as death within 2 hours of onset of underlying cause (n = 4,362), and the time of onset of the cause was determined by subtracting the "time elapsed until death" from the "time of death." The periodicity for time of onset of the cause was analyzed in groups stratified by year, season, sex and age with Rogers' method utilized to check the statistical significance of the periodicity. SD, as a whole, showed a statistically significant circadian variation with a low incidence during 0 to 4 A.M. and a high incidence during 6 to 8 A.M. and 6 to 8 P.M. By season, no significant circadian variation was seen in the summer unlike for other seasons. When analyzed by age group, no significant circadian variation in SD was seen for the young to middle aged group (15-54 years old). On the other hand, there was a significant circadian variation for the senior (55 to 74 years old) and the elderly group (75 years old or older) with a low incidence during 0 to 4 A.M. and high incidence during 6 to 12 A.M. and 6 to 8 P.M.. For the old age group, the number of the cases increased so remarkably as to form an evening peak. The percentage of SD for young to middle cases was higher in the summer than in the other seasons which may be the reason for absence of significant circadian variation in the summer.

Adolescent↗
PubMed1991

Pharmacokinetics of cis-diammine-dichlor-platin in a hemodialysis patient.

Cisplatin (CDDP) was administered to a 49-year-old dialysis female patient with advanced uterine cervical cancer. Analysis of the pharmacokinetics of CDDP in the patient with renal failure and at hemodialysis were compared with that of patients without renal impairment. CDDP at 30 mg was administered by drip infusion. The samples were ultrafiltrated and measured its concentration of both free (F-P) and total CDDP (T-P) by atomic absorption method. The effect of hemodialysis on the concentration of CDDP was analyzed. For the control, three patients without renal impairment were administered CDDP using the same method and its concentration was measured. The T-P clearance registered no difference between dialysis patients and controls, but F-P clearance in the HD patient was almost 5-fold lower than those in control patients, showing that F-P exposure to HD patients was 5-fold greater as a consequence of delayed disposition. The protein binding rate of CDDP was more gradual than that of the controls. The T-P and F-P removal rates positively correlated to the shunt side blood F-P.

Adenocarcinoma↗
PubMed1991

Biosynthesis and secretion of beta-thromboglobulin by a human megakaryoblastic cell line (MEG-01).

The de-novo synthesis and secretion of beta-thromboglobulin (BTG) by a human megakaryoblastic cell line (MEG-01) were studied by measuring and immunoblotting of BTG in culture supernatant and immunoprecipitation of radiolabeled BTG synthesized after incubation with [35S]methionine. It was demonstrated that BTG synthesized by MEG-01 was secreted into culture media in a monomer form having a molecular weight of 8,800. Furthermore, we purified BTG from culture medium of MEG-01 with a heparin affinity column and compared BTG from MEG-01 with that from normal platelets. The molecular weights of BTG purified from both sources were 8,800 using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). These results provide direct evidence for the synthesis and secretion of BTG by megakaryocytes.

Blood Platelets↗
PubMed1991

[Past histories of sudden death without specific underlying disease].

To study past histories of patients who died suddenly, we selected cases from all the summary death certificates in which death occurred within 24 hours from the onset of symptoms spanning 1984 to 1986 in Niigata prefecture with a population of 2.5 million. We then re-examined all information on the death certificates to determine the underlying causes. Sudden deaths due to cardiovascular diseases other than acute myocardial infarction and cerebrovascular accident (OCD) accounted for the largest proportion (51.4%). The proportion of death of unknown etiology increased with the decrease in age in both sexes aged 15 to 54 years, accounting for 67.8% in males and 51.1% in females. The number of cases with histories of diseases related to atherosclerosis (e.g. hypertension, old cerebrovascular accident, etc) increased with age in both sexes, accounting for 38.5% in males and 36.4% in females, both aged 75 years old and over. Except diseases related to atherosclerosis, the past histories accounted for 2.5% or greater were as follows: alcoholism (4.1%), psychiatric disorder (PSY, 2.9%) and valvular heart diseases (VD, 2.6%) in 15-54-year-old males; ischemic heart diseases (IHD, 9.4%), arrhythmia without organic heart diseases (ARR, 2.5%) and VD (2.5%) in 55-74-year-old male; IHD (11.4%), bronchial asthma (3.7%), common cold within one month (CC, 3.6%), cor pulmonale or its related diseases (3.0%) and ARR (2.6%) in male of 75 years old and over; PSY (8.7%), IHD (5.8%), VD (5.1%), pregnancy, delivery or related diseases (4.4%), chronic renal failure (3.6%) and CC (2.9%) in 15-54-year-old females; IHD (10.2%), VD (3.2%) and ARR (2.6%) in 55-74-year-old females; and IHD (11.8%) in females of 75 years old and over. When diseases related to atherosclerosis were included, half of the sudden death cases due to OCD had past histories of underlying cause. As descriptions of past histories are often incomplete, there were probably more cases with past histories. The results of this study indicate that investigation of past histories may aid in elucidating and preventing sudden death.

Adolescent↗
PubMed1991

Septicemia in patients with solid cancers in a Japanese cancer hospital--the significance of candidemia for cancer patients.

Episodes of septicemia (114) in patients with solid cancers at Nagoya Memorial Hospital were analyzed from April 1985 to June 1986. The underlying malignancies were predominantly gastric and colon cancers. Almost all the cancers were in advanced stages, the most frequent patient performance status being 4. Hypogammaglobulinemia and granulocytopenia were not, however frequent among these patients. The major microbes detected from blood cultures were Candida sp., Staphylococcus aureus and Staphylococcus epidermidis. Preceding chemotherapies were mainly combination chemotherapies containing Cisplatin (CDDP). The major pathogen, Candida sp., was detected frequently from Hickman's catheter. Thirty-one percent of patients died within 14 days of the septicemia diagnosis (two were cases of septic shock).

Anti-Bacterial Agents↗
PubMed1990

Early site of lymphatic involvement from right renal cell carcinoma: CT demonstration and method of lymphadenectomy.

The value of lymphadenectomy in the treatment of renal cell carcinoma remains controversial. The precise location of nodal metastasis and method of lymphadenectomy had seldom been mentioned. We report 2 patients with right renal cell carcinoma who had regional lymph node involvement without blood-borne metastasis. The involved lymph nodes were demonstrated by CT scan just behind the inferior vena cava at the level of renal hilus. These nodes seemed to be the first sites of nodal involvement from the right renal cell carcinoma. Elevation of the inferior vena cava by dividing its small branches, including a few lumbar veins, was necessary for complete removal of these nodes en bloc with the right kidney.

Aged↗