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Biomedical subjects

N Tanabe

Publications and source records attributed to N Tanabe.

At least 19 recordsLinked to original sources
PubMed2005

Hippocampal synthesis of estrogens and androgens which are paracrine modulators of synaptic plasticity: synaptocrinology.

Hippocampal pyramidal neurons and granule neurons of adult male rats are equipped with a complete machinery for the synthesis of pregnenolone, dehydroepiandrosterone, testosterone, dihydrotestosterone and 17beta-estradiol. Both estrogens and androgens are synthesized in male hippocampus. These brain steroids are synthesized by cytochrome P450s (P450scc, P45017alpha and P450arom), hydroxysteroid dehydrogenases and reductases from endogenous cholesterol. The expression levels of enzymes are as low as 1/300-1/1000 of those in endocrine organs. Synthesis is dependent on the acute Ca(2+) influx upon neuron-neuron communication via NMDA receptors. Estradiol is particularly important because estradiol rapidly modulates neuronal synaptic transmission such as long-term potentiation via synaptic estrogen receptors. Xenoestrogens may also act via estrogen-driven signaling pathways.

Androgens↗
PubMed2005

Behaviour of bone marrow osteoblast-like cells on mineral trioxide aggregate: morphology and expression of type I collagen and bone-related protein mRNAs.

AIM: To investigate the in vitro behaviour of rat bone marrow cells (RBM) on mineral trioxide aggregate (MTA) (ProRoot, MTA Root Canal Repair Material; Dentsply Tulsa, Tulsa, OK, USA) compared with intermediate restorative materials (IRM) (Dentsply Caulk, Milford, DE, USA). METHODOLOGY: RBM were obtained from rat femur and were primary cultured and then subcultured. Cells were then seeded on three dishes of each material, and cultured for 3 days, after which they were evaluated morphologically using scanning (SEM) and transmission (TEM) electron microscopy. Furthermore, the calcium released from hydrated material, the cell proliferation ratio and alkaline phosphatase (ALP) activity were analysed, and the expression of type I collagen and bone-related protein mRNAs were evaluated. The data were averaged and analysed via one-way analysis of variance (anova) and were then compared by the Scheffe's test. RESULTS: SEM showed that RBM attached to MTA and had a flattened appearance without nuclear protrusions and microspikes. TEM showed that the cells attached in the same manner as the control group, but gaps larger than 2 microm were frequently seen. The calcium released from hydrated MTA was about 130 ppm after 3 days of immersion in saline. The ALP activity was similar to the control group. Cell proliferation and expression of type I collagen mRNA was significantly lower, while the expression of osteopontin mRNA was significantly higher than the control group at the third day of culture. In IRM groups, a few rounded cells were observed on the material but no living cells were seen. CONCLUSIONS: MTA is a material of low toxicity which does not inhibit cell growth, but does suppress the differentiation of osteoblast-like cells.

Alkaline Phosphatase↗
PubMed2005

Association of clinical features with HLA in chronic pulmonary thromboembolism.

The aetiology of chronic thromboembolic pulmonary hypertension (CTEPH) is largely unknown and may be heterogeneous, because there are several ethnic differences in the clinical characteristics of CTEPH. Female predominance and a higher ratio of chronic to acute pulmonary thromboembolism have been reported in Japan as compared with the USA. Because such ethnic differences may be controlled by genetic factors, the current study investigated HLA polymorphisms in Japanese patients with CTEPH. HLA typing by serological and/or DNA typing methods was performed (for HLA-A, B, DPB1, DRB1) in 80 patients and 678 controls, and the association of clinical characteristics with HLA alleles was studied. The frequencies of HLA-B*5201 (40 versus 24%) and DPB1*0202 (19 versus 6%) were significantly higher in the patients. HLA-B*5201 positive patients showed a significant female predominance. Total pulmonary vascular resistance and mixed venous oxygen tension were better in the HLA-B*5201 positive patients. In contrast, cardiac index and gas exchange parameters were worse in the HLA-DPB1*0202 positive patients. In the patients carrying HLA-B*5201 and/or -DPB1*0202, the frequency of deep vein thrombosis was significantly lower than the other patients. These observations suggested that both the susceptibility and clinical characteristics of chronic thromboembolic pulmonary hypertension were controlled in part by the HLA-B and -DPB1 loci.

Adult↗
PubMed2003

Feasibility of combination chemotherapy with cisplatin and etoposide for haemodialysis patients with lung cancer.

Cancer chemotherapy for haemodialysis patients has never been established. To elucidate the feasibility of cisplatin-based combination chemotherapy for haemodialysis patients with lung cancer, a dose escalation study was conducted. Five haemodialysis patients with lung cancer were treated with cisplatin and etoposide. A starting dose of 40 mg m(-2) of cisplatin on day 1 and 50 mg m(-2) of etoposide on days 1, 3 and 5 were administered as the first course for the first patient. Membrane haemodialysis was regularly performed three times a week and soon after the completion of therapy. By monitoring toxicity and pharmacokinetics data, the dose was escalated course by course and patient by patient. Dose escalation was completed for the first two patients resulting in full-dose chemotherapy consisting of 80 mg m(-2) of cisplatin on day 1 and 100 mg m(-2) of etoposide on days 1, 3 and 5. Multiple courses of the full-dose chemotherapy were administered to the other three patients. Toxicity was manageable and tolerable for all. Pharmacokinetics data were comparable to those from patients with normal renal function, except for potential long-lasting higher levels of free platinum in the renal insufficiency group. In conclusion, this standard-dose combination chemotherapy was feasible even for haemodialysis patients.

Aged↗
PubMed2002

Comparison of gastroduodenal, renal and abdominal fat biopsies for diagnosing amyloidosis in rheumatoid arthritis.

The aim of the study was to determine the frequency of amyloidosis detected by gastroduodenal biopsy in rheumatoid arthritis (RA) patients, and to investigate correlations between the results of gastroduodenal biopsy and abdominal fat and renal biopsies. A total of consecutive 1006 RA patients underwent gastroduodenal biopsy. The 71 patients who tested positive for gastrointestinal (GI) amyloidosis were asked to undergo renal and abdominal fat biopsies, and 21 did so. Renal biopsies were also performed on 12 patients with no amyloidosis but indicators of drug-induced renal damage, and abdominal fat biopsies were performed on 50 RA patients with no indication of amyloidosis. The prevalence of GI amyloidosis was 7.1%. Urinary abnormalities and GI symptoms were common in GI amyloidisis, and inflammatory markers were elevated. Sixty-one (86%) had either depressed creatinine clearance or urinary symptoms. Nineteen of the 21 patients (91%) with GI amyloidosis who underwent renal biopsies also had renal amyloid deposits. Eleven of the 21 (52%) had amyloidosis on abdominal fat biopsy. None of the 12 patients without GI amyloidosis had renal amyloidosis on renal biopsy, and none of the 50 patients without GI amyloidosis had amyloidosis on abdominal fat biopsy. Gastroduodenal biopsy reveals a high prevalence of amyloidosis in RA patients. Amyloidosis is often associated with signs of renal impairment. Results of GI biopsy are highly correlated with those of renal biopsy, but the results of fat biopsy are not. We recommend GI biopsy for RA patients for the screening of systemic amyloidosis.

Abdominal Wall↗
PubMed2002

Interleukin-2 levels are elevated in the bone marrow serum of patients with mutilans-type rheumatoid arthritis.

In order to investigate the pathogenesis of mutilans-type rheumatoid arthritis (RA), we measured cytokine levels in the bone marrow serum of patients with RA. We studied 35 patients with non-mutilans RA, 19 with mutilans RA, and 20 patients with osteoarthritis (OA) undergoing joint surgery. At the time of surgery, iliac bone marrow and peripheral blood were sampled from all 74 patients and cytokine levels measured. The serum levels of five cytokines (IL-1beta, IL-2, IL-3, IL-6 and GM-CSF) were measured by ELISA. Haematologic and inflammatory factors were also measured. Levels of IL-2, IL-6 and GM-CSF in bone marrow serum were significantly higher in all RA patients than in those with OA. Mean (+/-SD) IL-2 levels were significantly higher in patients with mutilans-type RA (309.8+/-686.3 pg/ml) than in patients with other types of RA (66.5+/-173.1 pg/ml; P<0.01). IL-2 was detected significantly more often in patients with mutilans-type RA than in patients with other types of RA (P < 0.01). Inflammatory factors were higher in all RA groups than in OA patients. However, the haematologic and immunologic variables were no different between mutilans RA and other types of RA. No correlations were observed between IL-1beta, IL-2, IL-3, IL-6 and GM-CSF levels and these laboratory variables. In patients with mutilans-type RA, IL-2 levels in the bone marrow serum were significantly higher than in patients with other types of RA or with OA. This elevation does not appear to be related to systemic inflammation, as there was no correlation with other inflammatory factors.

Aged↗
PubMed2002

Ehlers-Danlos syndrome type IV with few extrathoracic findings: a newly recognized point mutation in the COL3A1 gene.

Ehlers-Danlos syndrome type IV (EDS IV) is caused by mutation within the COL3AI gene, resulting in the disorder of type III procollagen. The diagnosis is confirmed by demonstrating the synthesis of abnormal type III procollagen molecules from cultured dermal fibroblasts or by identifying the mutation in the COL3A1 gene. The authors report a case of EDS IV caused by a novel point mutation in the COL3A1 gene in a 16-yr-old female. Recurrent haemoptysis and cavitary formation of the lung were evidence of pulmonary involvement. However, extrathoracic manifestations of EDS IV were mostly absent. To the best of the authors' knowledge, all previously reported Ehlers-Danlos syndrome IV patients with respiratory disease had the characteristic findings or histories of Ehlers-Danlos syndrome IV. In the present case, connective tissue friability was suspected due to tissue laceration observed in the biopsied lung specimen, and the diagnosis was made beginning from this pivotal finding.

Adolescent↗
PubMed2001

Plasma monocyte chemoattractant protein-1 and pulmonary vascular resistance in chronic thromboembolic pulmonary hypertension.

The pathogenesis of severe pulmonary hypertension seems to be related to inflammatory response in diseased sites. Monocyte chemoattractant protein-1 (MCP-1) has been reported to play a role in the development of congestive heart failure. In this immunological response, activation and migration of leukocytes including macrophages to the inflammatory region are important factors. We hypothesized that the severity of pulmonary hypertension may be related to MCP-1, which is thought to be upregulated by blood pressure or shear stress in pulmonary vasculature as well as by immunological and inflammatory reactions in chronic thromboembolic pulmonary hypertension (CTEPH). Circulating levels of MCP-1, interleukin-1beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha) were measured by sandwich ELISA in 14 patients with CTEPH. The plasma level of MCP-1 was significantly correlated with pulmonary vascular resistance. In IL-1beta and TNF-alpha, on the other hand, there was no correlation between cytokines and pulmonary hemodynamics. Pathological specimens obtained from the patients with CTEPH undergoing thromboendarterectomy demonstrated immunoreactivity of MCP-1 in endothelium, smooth muscle cells, and macrophages within neointima in the hypertensive large elastic pulmonary artery. We conclude that MCP-1 is upregulated in the remodeling of pulmonary arteries in close association with increased pulmonary vascular resistance in CTEPH.

Adult↗
PubMed2001

The influence of fractional pulse pressure on the outcome of pulmonary thromboendarterectomy.

Although pulmonary thromboendarterectomy is an effective modality for the treatment of chronic thromboembolic pulmonary hypertension (CTEPH), the mortality in patients with severe haemodynamic disease is still high. Recently it was reported that fractional pulse pressure (pulmonary arterial pulse pressure/mean pulmonary arterial pressure) was higher in CTEPH than in primary pulmonary hypertension (PPH). It was hypothesized that fractional pulse pressure might be low in CTEPH with inaccessible distal thrombi and/or secondary pulmonary hypertensive change, resulting to the high operative mortality. To determine the influence of fractional pulse pressure to the outcome of surgery, 32 patients with CTEPH who had thromboendarterectomy between 1985 and 1998 were studied. Pulmonary haemodynamics and fractional pulse pressure were compared between survivors (n=26) and nonsurvivors (n=6) postoperatively. Those parameters in PPH (n=18) and large vessel pulmonary arteritis (n=6) were also analysed. Fractional pulse pressure in CTEPH (1.23+/-0.21) was significantly higher than in PPH (0.93+/-0.22; p=0.0017) and lower than in pulmonary arteritis (1.69+/-0.32; p=0.03). Fractional pulse pressure in survivors (1.26+/-0.21) was significantly higher than in nonsurvivors (1.06+/-0.16; p=0.03). Fractional pulse pressure is a significant predictor for mortality in patients with high pulmonary vascular resistance >1100 dynes.sec.cm(-5). To conclude fractional pulse pressure in addition to pulmonary vascular resistance might be useful in predicting for the outcome of surgery, especially in patients with severe haemodynamic impairment.

Adult↗
PubMed2001

[Clinical characteristics of asthmatics who stop peak expiratory flow monitoring (PFM)--analysis of patients who continued PFM more than eight weeks].

To estimate the effect of treatment and for patient education, we recommend 8 weeks PFM for all asthmatics when we start their treatments. To elucidate clinical characteristics of asthmatics who stop PFM, we analyzed 311 patients (145 males aged 15-76 years and 166 females aged 17-79 years) who could measure their PEFs twice daily for more than 8 consecutive weeks. The analysis of cumulative continuation rate of PEF monitoring revealed that the patients' withdrawal rate was 19% per year. The sixty asthmatics who gave up monitoring their PEFs (group A) showed significantly younger present ages (38.8 +/- 14.2, mean +/- S.D.) and younger ages of onset of their asthma (29.8 +/- 19.6) than the other 251 asthmatics who could continue to monitor their PEFs (group B). The present ages and ages of onset of asthma of group B were 46.2 +/- 16.7 and 37.6 +/- 21.2 years, respectively. Despite no significant differences in the severity of the asthma based on both clinical symptoms and PEF between groups A and B, the asthma severity based only on the clinical symptoms of group A were significantly less than those of group B. The analysis of Cox's proportional hazards model revealed that major factors which influence patients' stopping of PFM were present age and severity of their asthma which was estimated by the patients' symptoms only, without PEF assessment. These results suggest that asthmatics whose present age is young and whose ability of perception of asthma is poor will be apt to stop PFM.

Adolescent↗
PubMed2000

Effects of collateral vessel occlusion on oral glucose tolerance test in liver cirrhosis.

Alterations in carbohydrate metabolism associated with liver cirrhosis are characterized by a high serum insulin level and prolonged hyperglycemia on oral glucose tolerance test (OGTT). We measured plasma glucose, immunoreactive insulin (IRI), and C-peptide immunoreactivity (CPR) levels during a 75-g OGTT before and after varices obliteration in 10 cirrhotic patients with gastric varices. After obliteration, the indocyanine green retention rate was decreased and the portal flow velocity was increased. A significant decline in plasma glucose and IRI levels was also noted on OGTT. Moreover, the plasma glucose and IRI levels declined at 90 and 120 min in OGTT while they increased progressively by 120 min before obliteration. The levels of CPR were similar before and after treatment. These results indicate that decreased portal flow due to extrahepatic shunt and consequent impairment of insulin metabolism play a role in glucose intolerance observed in cirrhotic patients and that shunt occlusion improves glucose metabolism.

Adult↗
PubMed2000

Low dose carvedilol inhibits progression of heart failure in rats with dilated cardiomyopathy.

The cardioprotective properties of carvedilol (a vasodilating beta-adrenoceptor blocking agent) were studied in a rat model of dilated cardiomyopathy induced by autoimmune myocarditis. Twenty-eight days after immunization, surviving Lewis rats (32/43=74%) were divided into three groups to be given 2 mg kg(-1) day(-1) (Group-C2, n=10) or 20 mg kg(-1) day(-1) (Group-C20, n=10) of carvedilol, or vehicle (0.5% methylcellulose, Group-V, n=12). After oral administration for 2 months, body weight, heart weight (HW), heart rate (HR), rat alpha-atrial natriuretic peptide (r-ANP) in blood, central venous pressure (CVP), mean blood pressure (mean BP), peak left ventricular pressure (LVP), left ventricular end-diastolic pressure (LVEDP), +/-dP dt(-1) and area of myocardial fibrosis were measured. Values were compared with those for normal Lewis rats (Group-N, n=10). Two out of 12 (17%) rats in Group-V died from day 28 to day 42 after immunization. No rat died in Groups-C2, -C20 and -N. Although the CVP, mean BP, LVP and +/-dP dt(-1) did not differ among the three groups, the HW, HR and r-ANP in Group-C2 (1.14+/-0.03, 339+/-16 and 135+/-31) and Group-C20 (1.23+/-0.04, 305+/-8 and 156+/-24) were significantly lower than those in Group-V (1.36+/-0.04 g, 389+/-9 beats min(-1) and 375+/-31 pg ml(-1), respectively). The LVEDP in Group-C2 was significantly lower than that in Group-V (7.4+/-1.4 and 12.2+/-1.2 mmHg, respectively, P<0. 05). The area of myocardial fibrosis in Group-C2 was smaller than that in Group-V (12+/-1 and 31+/-2%, P<0.01). These results indicate that a low dose of carvedilol has beneficial effects on dilated cardiomyopathy.

Animals↗
PubMed2000

Influenza vaccination levels and influenza-like illness in long-term-care facilities for elderly people in Niigata, Japan, during an influenza A (H3N2) epidemic.

Surveys on influenza vaccination and illness in long-term-care facilities in Niigata Prefecture during an influenza A (H3N2) epidemic revealed that >20% of facilities had outbreaks and >10% of residents experienced influenza. Outbreaks and number of cases were significantly reduced by vaccination, which should be strongly recommended for institutionalized elderly people.

Aged↗
PubMed2000

Acute effects of endothelin-1 and TAK-044 (ET(A) and ET(B) receptor antagonist) in rats with dilated cardiomyopathy.

The hemodynamic effects of endothelin (ET)-1 and TAK-044 (ET(A) and ET(B) receptor antagonist) were studied in a rat model of dilated cardiomyopathy after autoimmune myocarditis. Six weeks after immunization, survived Lewis rats (30/43 = 70%) were randomly allocated into five groups to be given 0, 0.3, 3, 30 and 60 mg/kg/day (groups F0, F0.3, F3, F30 and F60; each group, n = 4) of TAK-044 using an osmotic pump subcutaneously. Age-matched normal Lewis rats (n = 26) were also randomly divided into four groups to be given 0, 0.3, 3 and 30 mg/kg/day (groups N0, N0.3, N3 and N30; each group, n = 4). ET-1 concentrations in plasma and myocardium were measured, and immunohistochemical detection of ET-1 in the left ventricle from the remaining rats (groups F and N) was performed. After administration of TAK-044 for 7 days, 2, 4, 11, 21 and 42 ng/min ET-1 every 20 min was infused using a pump, and the change in mean arterial pressure of each group during the infusion was examined. The plasma and myocardial ET-1 concentrations were significantly higher in group F than group N (12.3 +/- 1.5 vs. 5.4 +/- 0.2 pg/ml and 426 +/- 31 vs. 98 +/- 6 pg/g tissue; both p < 0.01). Strong positive signals for ET-1 were found to be widely distributed in the left ventricular myocardium of both groups of rats. Although the ET-1-induced increase in the mean arterial pressure was abolished in group N30, the maximal dose of ET-1 produced a 34% increase in the mean arterial pressure in group F30. Even in group F60, ET-1-induced hypertension was blocked incompletely. These results indicate that the heart may be a major ET-1-producing organ, and a higher dose of ET-1 antagonist is needed to block the effect of ET-1 in rats with dilated cardiomyopathy.

Animals↗
PubMed2000

Role of positive airway pressure on pulmonary acinar perfusion heterogeneity.

Perfusion of the pulmonary acinus has been shown to be generally homogeneous, but there is a significant component that is heterogeneous. To investigate the contribution of the alveolar septal capillary network to acinar perfusion heterogeneity, the passage of fluorescent dye boluses through the subpleural microcirculation of isolated dog lung lobes was videotaped using fluorescence microscopy. As the videotapes were replayed, dye-dilution curves were recorded from each of the tributary branches of Y-shaped venules that drained single acini. For each Y-shaped venule, the mean appearance time difference between the pair of tributary branches was calculated from the dye curves. When the complex septal capillary networks were derecruited by high positive airway pressure, venular perfusion became proportionally more homogeneous. This result shows that septal capillary resistance and pathlength differences are important contributors to intra-acinar perfusion heterogeneity.

Animals↗
PubMed2000

Eye examinations at the National Institute for Longevity Sciences--Longitudinal Study of Aging: NILS-LSA.

The National Institute for Longevity Sciences--Longitudinal Study of Aging (the NILS-LSA) started in 1997, and involves many kinds of examination. The objective of this paper is to outline the eye examinations in the NILS-LSA. The eye examinations consist of checks on refractometry, visual acuity, intraocular pressure, contrast sensitivity, kinetic visual acuity, visual fields, fundus photography, and lens estimation. The subjects were 1,077 men and women aged 40-79 years who participated in the first year examination of the NILS-LSA. All subjective measurements (distant visual acuity, kinetic visual acuity, contrast sensitivity, and mean sensitivity of visual field) declined significantly from the 50s. Age-related structural changes in the lens or hypertensive and arteriosclerotic changes in retinal vessels began at least in the 40s. It is suspected that aging affects the subjective visual functions from the 50s. However, changes in the structure of eye may begin before the 40s. The data from the eye examinations of the NILS-LSA are useful to assess the aging effects on vision and to investigate the relationship between visual function and physical or psychosocial health problems among the elderly.

Adult↗
PubMed2000

[A case of primary pulmonary artery myxosarcoma associated with severe pulmonary hypertension].

A 50-year-old man presented with progressive dyspnea on exertion, but with no history of chest pain or syncope. Chronic pulmonary thromboembolism was suspected and he was referred to our hospital. On ausculation, a grade 3 systolic murmur was heard, that was loudest in the fifth intercostal space lateral to the right sternal border. Chest radiography showed mild cardiomegaly and ventilation-perfusion scan revealed absence of perfusion in the left lung and the upper field of the right lung. Contrast-enhanced helical CT showed large mural defects in both main pulmonary arteries, clearly delineated by contrast medium. The left pulmonary artery was nearly completely occluded, and eccentric defects were observed projecting into the lumen of the pulmonary trunk. A tumor originating in the pulmonary artery was suspected, but a definitive diagnosis of the mass could not be made with pulmonary angiography and magnetic resonance imaging. The mean pulmonary arterial pressure was 50 mmHg. Further radiologic examinations failed to reveal the source of the embolus or tumor. It was decided to attempt surgical excision under total cardiopulmonary bypass. At operation, a gelatinous, lustrous, yellowish mass was found partially occluding the right main pulmonary artery and completely occluding the left. The tumor adhered tightly to the intima of the vessel and was inoperable. The patient could not be weaned from percutaneous cardiopulmonary support and died 3 days after surgery. Histologic examination of the excised specimen revealed myxosarcoma.

Chronic Disease↗