Biomedical subjects

G Tanaka

Publications and source records attributed to G Tanaka.

At least 19 recordsLinked to original sources

PubMed2006

Tumour necrosis factor and lymphotoxin A polymorphisms and lung function in smokers.

Genetic variants in the tumour necrosis factor (TNF) gene have been investigated in chronic obstructive pulmonary disease (COPD). However, there are many instances of nonreplication of these associations due to insufficient power or other factors. In this study, a large number of subjects were examined to elucidate whether genetic variations of TNF and/or lymphotoxin A (LTA), which is clustered with TNF, are associated with variations in lung function among smokers. The present authors designed two nested case-control studies in the National Heart, Lung, and Blood Institute Lung Health Study (LHS), which enrolled 5,887 smokers. The first design included continuous smokers who had the fastest (n = 279) and the slowest (n = 304) decline of lung function during the 5-yr follow-up period, and the second included the subjects who had the lowest (n = 533) and the highest (n = 532) post-bronchodilator % predicted forced expiratory volume in one second at the start of the LHS. Within the TNF and LTA region, 10 tagging single-nucleotide polymorphisms were selected and genotyped. Unlike the previous associations between TNF-308 and COPD in Asians, the current study found no association between either of the two phenotypes and the LTA and TNF polymorphisms. In conclusion, these results support the findings of previous studies in late-onset chronic obstructive pulmonary disease in Caucasian populations.

Case-Control Studies↗

PubMed2005

Crisis-induced intermittency in two coupled chaotic maps: towards understanding chaotic itinerancy.

The present paper considers crisis-induced intermittency in a system composed of two coupled logistic maps. Its purpose is to clarify a bifurcation scenario generating such intermittent behaviors that can be regarded as a simple example of chaotic itinerancy. The intermittent dynamics appears immediately after an attractor-merging crisis of two off-diagonal chaotic attractors in a symmetrically coupled system. The scenario for the crisis is investigated through analyses of sequential bifurcations leading to the two chaotic attractors and successive changes in basin structures with variation of a system parameter. The successive changes of the basins are also characterized by variation of a dimension of a fractal basin boundary. A numerical analysis shows that simultaneous contacts between the attractors and the fractal basin boundary bring about the crisis and a snap-back repeller generated at the crisis produces the intermittent transitions. Furthermore, a modified scenario for intermittent behaviors in an asymmetrically coupled system is also discussed.

Journal Article↗

PubMed2004

Expression of glucose transporter 5 by microglia in human gliomas.

Our previous studies indicate that glucose transporter 5 (GLUT5) is a microglial marker in routine paraffin sections, and is rarely present in monocytes/macrophages of the peripheral organs. We examined the expression of GLUT5 in 91 cases of human gliomas to characterize the microglial phenotype in glioma tissues. Immunohistochemistry was performed on formalin-fixed, paraffin-embedded sections using such antibodies as a GLUT5 antibody, two markers for activated microglia: major histocompatibility complex (MHC) class II Ag and macrophage scavenger receptor class A (MSR-A), and MIB-1 antibody. The immunoreactivity of GLUT5 was present in three microglial phenotypes: ramified (resting), activated, and ameboid (macrophagic) microglia in most of the cases. A double-labelling study of astrocytic tumours using GLUT5 and MIB-1 antibodies demonstrated a proportion of proliferating microglia. However, no morphological difference between MIB-1-positive, microglial cells and MIB-1-negative, microglial cells was found. The number of GLUT5-positive microglia was significantly (P < 0.001) higher in astrocytic tumours than in oligodendroglial tumours. Many GLUT5-positive microglia (up to 52% in total cells) were often observed in pilocytic astrocytomas, where microglial cells were predominantly ramified, and the number of MHC class II- or MSR-A-positive microglia was less than GLUT5-positive microglia. Thus, the present study indicated that intrinsic microglia can be a source of microglia/macrophages cell populations in astrocytic tumours, and that pilocytic astrocytomas often have a high proportion of microglial cells with mild activation.

Blotting, Western↗

PubMed2003

[Liposarcoma of the pleural cavity; report of a case].

A 43-year-old-woman who had sever anterior chest pain visited our hospital on April 3, 2000. A well-defined abnormal shadow was seen in the middle and lower field of the right lung on chest X-ray. Computed tomography showed a large fat density mass in the right pleural cavity with a septum enhanced by contrast medium. Percutaneous needle biopsy revealed lipoma or liposarcoma. Complete resection could be done with combined resection of right lung, lpericardium, parietal pleura and diaphragm. Final histologic diagnosis was well differentiated liposarcoma. There are few reports of liposarcoma arising in the thoracic cavity, we present our case and review the 23 cases reported from the Japanese literatures.

Adult↗

PubMed2001

Normalized pulse volume (NPV) derived photo-plethysmographically as a more valid measure of the finger vascular tone.

Normalized pulse volume (NPV) was advocated as a more valid measure for the assessment of finger vascular tone. Based on the optical model in the finger tip expressed by Lambert--Beer's law, NPV is expressed as Delta I(a)/I. Here, Delta I(a) is the intensity of pulsatile component superimposed on the transmitted light (I). Theoretically, NPV seems to be superior to the conventional pulse volume (PV; corresponding to Delta I(a)). Firstly, NPV is in direct proportion to Delta V(a), which is the pulsatile component of the arterial blood volume, in a more exact manner. Relatedly, NPV can be processed as if it is an absolute value. Secondly, the sensitivity of NPV during stressful stimulations is expected to be higher. These expectations were supported experimentally using 13 male students. Firstly, the correlation between cutaneous vascular resistance in the finger tip (CVR) and NPV was higher than that between CVR and PV among all the subjects, although there was not much difference between these correlations within each subject. Secondly, NPV decreased much more than PV during mental stress. Some limitations of the present study were addressed, including the point that certain factors can violate the direct proportional relationship of NPV and PV to Delta V(a).

Adult↗

PubMed2001

Diastolic flow velocity of the left pulmonary artery of patent ductus arteriosus in preterm infants.

BACKGROUND: The usefulness of diastolic pulmonary flow velocity determined by echocardiography in the assessment of symptomatic patent ductus arteriosus (sPDA) in preterm infants has not been confirmed. METHODS: Echocardiography was performed daily in infants ranging from 23 to 31 gestational weeks of age, and diastolic flow velocity of the left pulmonary artery (DFLPA) was measured. The DFLPA data before indomethacin administration for sPDA were compared with data obtained after indomethacin administration. The normal range of DFLPA was also determined from serial measurements performed in infants who did not develop sPDA during the first 7 days of life. Then, this range was compared with data from infants who did develop sPDA during this time. RESULTS: In infants who underwent indomethacin treatment, DFLPA increased with the development of sPDA and decreased when the symptoms of sPDA disappeared. On the basis of results from serial DFLPA measurement, the sensitivity and specificity of DFLPA for assessing sPDA was found to be 0.82 and 0.83, respectively. CONCLUSIONS: Measurement of DFLPA by echocardiography is a useful method for assessing sPDA in preterm infants.

Blood Flow Velocity↗

PubMed2000

Beat-by-beat double-normalized pulse volume derived photoplethysmographically as a new quantitative index of finger vascular tone in humans.

Near-infrared finger photoplethysmograms were recorded and double-normalized pulse volumes (DNPV = DeltaV(b)/V(b); V(b) = total blood volume in the fingertip, DeltaV(b) = pulsatile component of V(b)) were calculated in ten subjects during, immersion of the contralateral hand in water at three different temperatures (44 degrees C, 22 degrees C, 11 degrees C). The DNPV from the left finger was compared beat-by-beat with cutaneous vascular resistance (CVR) derived by dividing mean blood pressure of the left third finger by cutaneous blood flow of the left fourth finger. The correlations overall at the three temperatures between log DNPV(LF) and log CVR(LF) (LF, low frequency component of DNPV and CVR) ranged from -0.89 to -0.96 among the subjects. After adjusting for a maximal extension of the vascular wall (DNPV(max)), the correlations became stronger. It was concluded that DNPV was a reliable and valid indicator of vascular tone in the finger.

Adult↗

PubMed2000

N-[4-(3-ethoxy-2-hydropropoxy)phenyl] acrylamide selectively induces apoptosis of cerebellar granule cells in vivo and in vitro in rats.

Oral administration of N-[4-(3-ethoxy-2-hydropropoxy)phenyl] acrylamide (EHA) induced selective granule cell destruction in the granular layer of the cerebellar cortex together with neurological signs, such as delayed righting reflex, gait or truncal ataxia, and convulsion. Neuropathologically, it caused multifocal granule cell destruction with nuclear pyknosis and spongiosis of the neuropile in the granular layer. Other neurons, including Purkinje cells, were spared. Ultrastructurally, damaged granule cells showed aggregation of nuclear chromatin and cytoplasmic edema, but cytoplasmic organelles were preserved. The brain uptake index of 14C-labeled EHA was similar to that of H2O. When EHA was added to rat cerebellar tissue cultures, only the granule cells showed nuclear pyknosis, aggregation of nuclear chromatin, and karyorrhexis with cytoplasmic swelling. These granule cells were positive for DNA fragmentation by the TUNEL method. These results suggest that EHA permeates the blood vessel wall and directly affects the cerebellar granule cells, resulting in selective granule cell apoptosis.

Acrylamides↗

PubMed2000

Role of infection in the development of acquired subglottic stenosis in neonates with prolonged intubation.

OBJECTIVE: To examine whether clinically diagnosed infection correlates with subsequent development of subglottic stenosis in intubated neonates. METHODS: Sixty-two neonatal infants intubated for more than 14 days were examined. Several risk factors for subglottic stenosis, including infection, duration of intubation, frequency of intubation, the size of the endotracheal tube etc., were evaluated by multiple logistic regression analysis. RESULTS: Infection that occurred within 14 days of intubation showed a positive correlation with subsequent subglottic stenosis. The duration of intubation, frequency of intubation and the size of the endotracheal tube did not affect the development of subglottic stenosis. The majority of infections were considered to be respiratory tract infections, including pneumonia. CONCLUSIONS: Infection occurring within 14 days of intubation is considered to be a risk factor for acquired subglottic stenosis in neonates intubated for more than 14 days. Prevention of infection within 14 days of intubation may reduce the incidence of subglottic stenosis in neonates.

Gestational Age↗

PubMed2000

Prophylactic administration of granulocyte colony-stimulating factor when monocytopenia appears lessens neutropenia caused by chemotherapy for lung cancer.

In a retrospective study, we showed that a monocyte count of <150/microl on days 6 to 8 might be a predictor of grade III or IV neutropenia during cancer chemotherapy given at 3- or 4-week intervals. In the present study, we investigated whether the administration of granulocyte colony-stimulating factor (G-CSF) when monocytopenia appears lessens neutropenia during chemotherapy for lung cancer. Between June 1997 and August 1998, 60 patients who received chemotherapy at 3- or 4-week intervals for unresectable lung cancer were randomized to receive G-CSF (2 microg/kg or 50 microg/m2) when monocytopenia (<150/microl) appeared on days 6 to 8 after chemotherapy (group A) or when neutropenia (<1,000/microl) or leukopenia (<2,000/ microl) appeared after chemotherapy (group B). The administration of G-CSF was stopped when the leukocyte or neutrophil counts reached > 10,000/microl or 5,000/microl, respectively. The blood cells counts were examined three times a week and the degree, duration, and frequency of chemotherapy-induced neutropenia of the two groups were compared. One patient in group A was excluded because whole brain irradiation during chemotherapy was required. Twenty-nine and 30 patients in groups A and B, respectively, received platinum-based chemotherapy and their chemotherapy-induced hematologic toxicities were analyzed. The mean neutrophil count nadir of group A (1,558 +/- 1,771/microl) was significantly higher than that of group B (810 +/- 639/microl, p = 0.032). The duration of grade III neutropenia in group A (1.4 +/- 1.7 days) was significantly shorter than that in group B (2.9 +/- 1.9 days, p = 0.004), and the frequency of grade III neutropenia in group A (48%) was significantly lower than that in group B (83%, p = 0.002). Infectious episodes occurred in five and eight patients in groups A and B, respectively. The durations of G-CSF therapy required by group A and B patients (4.8 +/- 3.1 vs. 4.7 +/- 2.7 days) were not significantly different. Prophylactic administration of G-CSF did not exacerbate anemia or thrombocytopenia induced by chemotherapy. We conclude that the prophylactic administration of G-CSF when monocytopenia appears can lessen neutropenia caused by chemotherapy for lung cancer without increasing the total G-CSF dose.

Adult↗

PubMed2000

[Acute respiratory failure caused by tuberculosis requiring mechanical ventilation].

The patients with active tuberculosis in whom respiratory failure requiring mechanical ventilation developed were studied retrospectively. Nine patients (M 8, F 1) were identified at the National Tokyo Hospital during 5 years from January, 1993 to December, 1997. Seven of 9 patients were single men, and the duration of symptoms before admission was over 1 month in all patients, while the time from first visit to diagnosis was less than 7 days. All patients were identified as malnourished, and 7 patients suffered from another underlying diseases. The patients were classified into two groups. Six of 9 patients had pulmonary tuberculosis and the other three had miliary disease. The proportion of cases requiring mechanical ventilation was 0.3% and 8.6%, respectively, in pulmonary tuberculosis and miliary tuberculosis. At the start of mechanical ventilation, PaO2/FIO2 was lower than 200 in all 9 patients, and 6 patients were probably ARDS. Steroids (methylprednisolone 250-1000 mg/day) were used in all 9 patients. Despite the use of mechanical ventilation and antituberculous therapy, 8 out of 9 patients died. Only one patient with miliary tuberculosis survived. The establishment of the therapy for acute respiratory failure is needed so as to improve prognosis of such cases. At the same time, the delay in consulting a doctor led to acute respiratory failure in most cases, so it is also important to encourage tuberculosis patients to visit a doctor as soon as possible, after the appearance of symptoms.

Acute Disease↗

PubMed2000

[A case of mixed connective tissue disease with lupus-like manifestations of the central nervous system, successfully treated with cyclophosphamide combined with prednisolone].

A 29-year-old woman experienced Raynaud's phenomenon, swelling of her fingers, eruptions on her face, and muscle weakness in 1990. She was diagnosed as having mixed connective tissue disease (MCTD) and was treated with prednisolone (PSL) for 3 years. Most of her complaints disappeared after the treatment. In March 1997, she experienced fever, erythema, and lymphadenopathy. Although she was treated with PSL (20 mg/day) again, muscle weakness, mental disturbance, and recto-urinary disturbance appeared. When she was re-admitted to our hospital, increased levels of muscle-derived enzymes and positivity of anti-RNP antibody were found. High signal areas in her cerebrum were shown by magnetic resonance imaging, and slow and spike pattern was shown by electroencephalography. Hypoperfusion of the cerebral blood flow was suggested on single photon emission computed tomography. The number of mononuclear cells, amount of protein and level of interleukin-6 were found to be elevated in her cerebrospinal fluid (CSF). Her neurological manifestations were diagnosed as being due to MCTD, and showed characteristics similar to those of systemic lupus erythematosus. She was treated with PSL (60 mg/day) followed by steroid pulse therapy. Because the response to this treatment was partial, oral administration of cyclophosphamide (CPM) (100 mg/day) was added. Muscle weakness and neurological abnormalities as well as abnormal laboratory findings gradually improved over the following two months. We conclude that the treatment with CPM combined with PSL may be useful, when neurological manifestations of MCTD are serious and resistant to conventional therapy.

Adult↗

PubMed1999

Spatial and temporal variation of secondary flow during oscillatory flow in model human central airways.

Axial and secondary velocity profiles were measured in a model human central airway to clarify the oscillatory flow structure during high-frequency oscillation. We used a rigid model of human airways consisting of asymmetrical bifurcations up to third generation. Velocities in each branch of the bifurcations were measured by two-color laser-Doppler velocimeter. The secondary velocity magnitudes and the deflection of axial velocity were dependent not only on the branching angle and curvature ratio of each bifurcation, but also strongly depended on the shape of the path generated by the cascade of branches. Secondary flow velocities were higher in the left bronchus than in the right bronchus. This spatial variation of secondary flow was well correlated with differing gas transport rates between the left and right main bronchus.

Bronchi↗

PubMed1999

Detection of K-ras mutations of bronchoalveolar lavage fluid cells aids the diagnosis of lung cancer in small pulmonary lesions.

An increased prevalence of K-ras oncogene mutation in lung adenocarcinoma has been shown by PCR-primer-introduced restriction with enrichment for mutation alleles (PCR-PIREMA) experiments. In the present study we investigated whether this method is useful for the diagnosis of lung cancer in small pulmonary lesions, which are difficult to diagnose cytologically as lung cancer by bronchoscopic examination. We examined bronchoalveolar lavage fluid (BALF) cells from 33 patients with single nodular pulmonary lesions of less than 2 cm in diameter (measured on chest computed tomography scans) for K-ras (codon 12) mutation, by PCR-PIREMA. Transbronchial fiberscopic examinations had not revealed lung cancer cytologically in any of the patients. The final diagnoses for the 33 lesions were 20 adenocarcinomas, 5 cases of focal fibrosis, 5 cases of pneumonia, 1 case of tuberculosis, 1 hamartoma, and 1 case of lymph node swelling. BALF cell lysates were amplified and digested with a restriction enzyme to detect the K-ras oncogene. Only the normal K-ras was observed after the first amplification and digestion for each of the 33 patients. Three amplifications and digestions were performed for each sample. We detected mutation of K-ras in BALF cells from 15 (75%) of 20 lung cancer patients and in cells from only 4 (31%) of 13 patients with nonmalignant lesions. The detection rate of the K-ras mutation in lung cancer was significantly greater than that in nonmalignant lesions (P = 0.012). Our results indicate that the detection of the codon 12 K-ras mutation in BALF cells by PCR-PIREMA aids the diagnosis of lung cancer in patients with small pulmonary lesions with negative cytological findings.

Aged↗

PubMed1999

[Active pulmonary tuberculosis in patients with lung cancer].

To clarify the features of the coexistence of active pulmonary tuberculosis in patients with lung cancer, we analyzed clinical data on 25 cases with coexisting lung cancer and active pulmonary tuberculosis encountered at Tokyo National Chest Hospital during the period from 1991 to 1998. There were 23 men and 2 women, with a mean age of 70 years. The incidence of lung cancer among patients with active pulmonary tuberculosis at our hospital was 0.7 per cent, while the incidence of active pulmonary tuberculosis in untreated lung cancer patients at our hospital was 1.9 per cent. We classified the 25 cases into 2 groups as follows: (1) tuberculosis sequential to lung cancer (11 cases) and (2) tuberculosis concurrently detected with lung cancer (14 cases). All patients in the former group were transferred from other hospitals after diagnosing the coexistence of pulmonary tuberculosis during the management of lung cancer. Histological types of lung cancer were squamous cell carcinoma in 12, adenocarcinoma in 9, and small cell carcinoma in 4, and as to the disease stage, stages III to IV were predominant. Analysis on relationship of chest X-ray findings between lung cancer and pulmonary tuberculosis revealed that in general, the location of lung cancer and tuberculosis seemed to be independent. Tuberculosis in the sequential group was more extensive and severer than in the concurrent group. In the concurrent group, treatment for tuberculosis was successful except for one case, and coexisting tuberculosis did not seem to affect the course of lung cancer among this group. However, in the sequential group, 5 patients died within 3 months, 2 of them died of tuberculosis. We consider that in the management of lung cancer, physicians should consider the possibility of coexistent active pulmonary tuberculosis and should not make delay in the diagnosis of active pulmonary tuberculosis.

Adenocarcinoma↗

PubMed1998

Augmentation of axial dispersion by intermittent oscillatory flow.

The efficiency of axial gas dispersion during ventilation with high-frequency oscillation (HFO) is improved by manipulating the oscillatory flow waveform such that intermittent oscillatory flow occurs. We therefore measured the velocity profiles and effective axial gas diffusivity during intermittent oscillatory flow in a straight tube to verify the intermittency augmentation effect on axial gas transfer. The effective diffusivity was dependent on the flow patterns and significantly increased with an increase in the duration of the stationary phase. It was also found that the ratio of effective diffusivity to molecular diffusivity is two times greater than that in sinusoidal oscillatory flow. Moreover, turbulence during deceleration or at the beginning of the stationary phase further augments axial dispersion, with the effective diffusivity being over three times as large, thereby proving that the use of intermittent oscillatory flow effectively augments axial dispersion for ventilation with HFO.

Diffusion↗

PubMed1997

New technique for time series analysis combining the maximum entropy method and non-linear least squares method: its value in heart rate variability analysis.

A new technique for time series analysis, which is a combination of the maximum entropy method (MEM) for spectral analysis and the non-linear least squares method (LSM) for fitting analysis, is described. In this technique, the MEM power spectral density (MEMPSD) is calculated using a very large lag that could diminish the lag dependence of dominant periods estimated by the MEM analysis. The validity of this large lag is confirmed by the LSM, given that the ten dominant MEM periods are known quantities. To validate the MEM plus LSM technique, it is compared with autoregressive (AR) modelling, by analysing heart rate variability under pharmacological interventions (phenylephrine and trinitroglycerine), using 16 young males. The results indicate that the MEMPSD, when compared with the ARPSD, has numerous periods that could reproduce the original time series much more accurately, as revealed by the LSM analysis. However, both the low- and high-frequency powers with MEMPSD and ARPSDs shift in the expected directions in accordance with the pharmacological effects on the cardiovascular system. The implications of these results are discussed from the theoretical and practical standpoints of the MEM plus LSM technique, compared with AR modelling.

Adolescent↗

PubMed1996

Preattentive and focal attentional processes in schizophrenia: a visual search study.

Using a visual search task, the present study investigated preattentive and focal attentional processes in schizophrenic patients. The performance of 15 schizophrenic patients and 20 normal subjects was compared in three search tasks: feature search, 2-D feature search, and conjunction search. The target item was a red 'X' in all search tasks, and the distractor items were red 'O' in the feature search, green 'O' in the 2-D feature search, and red 'O' and green 'X' in the conjunction search. Set size total number of items presented in the display was 4, 16, or 25. Reaction times (RTs) for the subject's correct detection of target presence and absence were measured, and slopes of linear function relating RT to set size were computed. In the feature and the 2-D feature search, the schizophrenic subjects showed nearly zero slopes as did the normal subjects, indicating that in the preattentive process the schizophrenic patients functioned at a normal level. In the conjunction search, the schizophrenic subjects showed steeper slopes than the normal subjects for target absence (but not for target presence), suggesting that there was a deficit in the focal attentional process. Those results are consistent with the view of Callaway and Naghdi (1982) that a deficit in schizophrenic patients is mainly confined to the attentional process (cf., Lieb et al., 1994).

Adult↗