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Biomedical subjects

Y Fukuchi

Publications and source records attributed to Y Fukuchi.

At least 19 recordsLinked to original sources
PubMed1992

Low ligand binding activities of two distinct types of Fc gamma receptor on guinea-pig peripheral blood polymorphonuclear leukocytes are differentially improved by proteolysis or platelet activating factor.

The expression and ligand binding activity of Fc receptors for IgG (Fc gamma R) on guinea-pig peripheral blood polymorphonuclear leukocytes (blood PMN) have been compared with those on casein-elicited peritoneal PMN (exudate PMN). Both the PMN were found to express two distinct types of Fc gamma R, one specific for IgG1 and IgG2 (Fc gamma 1/gamma 2 R) and the other for IgG2 alone (Fc gamma 2 R), when evaluated by their reactivity to monoclonal antibodies (mAb) directed against each type of Fc gamma R. The surface density of Fc gamma 1/gamma 2 R was not significantly different between the two cell types, whereas exudate PMN expressed five times as many Fc gamma 2 R as blood PMN. Moreover, IgG immune complex (IC) binding activities of both the Fc gamma R on blood PMN were markedly low as compared with those on exudate PMN. In addition, blood PMN could not significantly generate superoxide anion (O2-) when exposed to IC. However, these lower activities were improved by protease treatment of the cells or by incubation with platelet activating factor (PAF). Fc gamma 2 R on blood PMN was found to be sensitive to pronase, whereas Fc gamma 1/gamma 2 R was resistant. Pronase-treated blood PMN showed a marked IC binding activity, though they lacked Fc gamma 2 R. This activity was completely blocked by anti-Fc gamma 1/gamma 2 R mAb, indicating that the proteolysis augments the ligand binding capacity of Fc gamma 1/gamma 2 R. In contrast, PAF was found to specifically modulate Fc gamma 2 R. The Fc gamma 2 R expression was significantly increased within 5 min incubation with PAF, whereas that of Fc gamma 1/gamma 2 R was not affected. The cells also exhibited enhanced IgG2-IC binding and subsequent O2- generating activities. These results indicate that both the Fc gamma R on blood PMN are functionally immature and are converted to exhibit intrinsic activities by proteases and PAF; such changes may occur in vivo during exudation and at inflammatory sites.

Animals↗
PubMed1992

Inhibition of mouse alveolar macrophage production of tumor necrosis factor alpha by acute in vivo and in vitro exposure to tobacco smoke.

We investigated the effects of tobacco smoke exposure on the production of tumor necrosis factor alpha (TNF alpha) by alveolar macrophages (AM) in mice (C57BL/6). The results obtained are as follows: (1) In vivo tobacco smoke exposure caused a significant decrease in the production of TNF alpha by AM with the stimulation of lipopolysaccharide (LPS; control group: 19.32 +/- 5.52 U/ml, smoked group: 4.28 +/- 0.98 U/ml; p less than 0.05). (2) In vitro exposure of AM to tobacco smoke extracts (water-soluble extracts) also caused a decrease in the production of TNF alpha up to 93% of control with stimulation of LPS (p less than 0.05) without any decrease in cellular viability. We concluded that the production of TNF alpha by AM was impaired by smoking via direct action of the factors present in tobacco smoke.

Animals↗
PubMed1992

Quantitative assessment of dyspnea during exercise before and after bullectomy for giant bulla.

Incremental exercise testing using a cycle ergometer was performed in eight patients with giant bulla before and after bullectomy to assess dyspnea. There was a significant positive linear relationship between dyspnea expressed in the Borg scale (BS) and oxygen consumption (VO2) during exercise in all subjects. From these correlations, we introduced the following three new parameters for quantitative assessment of dyspnea: the Borg scale slope (BSS); the threshold load of dyspnea (TLD); and the breakpoint load of dyspnea (BLD), representing the slope of the regression line, onset of dyspnea on the regression line, and the maximum oxygen consumption before the subjects interrupted exercise, respectively. After surgery, the BSS showed marked decrease, and the TLD and BLD showed significant increase. Therefore, the reduction in the dyspnea with peak exercise after surgery was thought to be, at least in part, based on the delay of dyspnea onset, the decrease in dyspnea sensitivity, and the improvement in exercise capacity. The improvement in dyspnea during exercise in patients with giant bulla after surgery was extensively evaluated by newly introduced parameters based on BS-VO2 regression line.

Blister↗
PubMed1992

Gerontological education in Japan--geriatric education and training.

There are 13 academic geriatric departments among 80 medical schools in Japan as of November 1991. The first independent department was established in 1962 at Tokyo University. The undergraduate education program includes lectures in geriatrics (20 hours/year in 11/12 medical schools), bedside teaching at geriatric ward (6/12 medical schools, 66 hours on average per year). The theme of lectures are diverse and incorporate all the three major fields in gerontology: biology of aging, clinical geriatrics and socio-economical aspects of aging society. The postgraduate geriatric education is carried out mainly at university setting and most of the medical schools (83%) accept graduate students who are trained at independent geriatric ward (92%) as well as at outpatient clinics. In 1989, Japan Geriatrics Society started a new certification system by which 687 MDs have been temporarily certified in geriatrics. The first examination will be given by the society in 1992 and the eligibility to sit in the examination requires three years geriatrics fellowship after certification in medicine or general surgery. The curriculum proposed by the society shares many items of training in common with those found in north American and in Europe. Some points of suggestions and recommendations were presented for future improvement in the education of gerontology in Japan.

Certification↗
PubMed1992

Age-related changes in GSH content of eyes in mice--a comparison of senescence-accelerated mouse (SAM) and C57BL/J mice.

1. Age-related changes in glutathione (GSH) content of eye lenses were investigated in senescence-accelerated mouse (SAM) and C57BL/J mice. 2. The decrease of GSH content with aging is markedly observed in SAM strains. 3. The oxidized glutathione (GSSG) content of eyes increased significantly with aging in SAM. 4. Ophthalmic changes, including cataract, increased with age in SAM alone. 5. The decrease of GSH content and the increase of GSH oxidation may be involved in the pathogenesis of cataract in SAM.

Aging↗
PubMed1992

[Problems in ulcer surgery after the introduction of H2-receptor antagonists].

Recently, antisecretory drugs such as H2-receptor antagonists (H2-RA) or proton pump inhibitor have been used for peptic ulcer patients widely in Japan. However, there are possibilities that long term administration of H2-RA might cause changes in intragastric environment. The present study was designed to clarify the changes of surgical treatment in Japan Surgical Society training hospitals, before and after introduction of H2-RA. Serum gastrin and antral G-cell number was measured after administration of H2-RA (1 mg/kg 14 days continuous infusion) in rat. Also, acid secretion and gastrin response stimulated by adrenalin (40 ng/kg.min) were measured in duodenal ulcer patients. 1) In the view of surgical treatment, elective operation highly decreased after the introduction of H2-receptor antagonists, and showed the increase of the rate of emergency operation up to 70%. 2) Hypergastrinemia and antral G cell hyperplasia were observed after administration of H2-RA in rats. 3) Acid secretion stimulated by adrenalin which is considered as antral G cell dependent, showed a higher response in H2-RA treated cases than in those untreated. 4) Antrectomy was carried out in 43.4% of the patients treated with H2-RA versus 18.9% to the patients untreated.

Animals↗
PubMed1992

[Pharmacokinetics and clinical efficacy of ciprofloxacin in aged patients with chronic respiratory diseases].

Pharmacokinetics and clinical efficacy of ciprofloxacin (CPFX) were investigated in aged patients with chronic respiratory diseases. Serum and sputum concentrations of CPFX were determined upon oral administration of 200 mg CPFX in 6 aged patients with chronic respiratory diseases (mean age = 78.8 +/- 3.2 years, 2 cases diagnosed chronic obstructive pulmonary disease with pneumonia, 3 cases were diagnosed bronchiectasis with acute exacerbation, and 1 case diagnosed chronic lung abscess). Maximal serum concentrations in these patients were 0.88-1.29 micrograms/ml (mean = 1.08 micrograms/ml). Thus, maximal serum concentrations of CPFX after oral administration in these aged patients were slightly lower than those in young subjects. However, peak sputum levels of CPFX following oral administration of 200 mg CPFX ranged from 0.53 to 1.47 micrograms/ml at 1-4 hours. These sputum concentrations of the 6 patients were sufficiently high for the inhibition of most infecting organisms in vitro. Clinical responses to CPFX in these 6 patients were good in 5, fair in 1, with an efficacy rate of 100%. Upon administration of CPFX, these 6 patients did not show any adverse reactions. These results suggest that oral administration of CPFX may keep effective levels in serum and sputum over 3 hours in aged patients with chronic respiratory diseases, and good clinical responses should be obtained without side effects in such patients.

Aged↗
PubMed1992

[The effect of ageing on airway responsiveness].

In order to evaluate the significance of airway responsiveness in the elderly: 1. Airway responsiveness in the healthy elderly was evaluated and compared with that of the healthy young adults. Methacholine dose response curve was constructed by measuring total respiratory resistance using the modified partial airway occlusion method which provides a simple, convenient, and non-invasive assessment of the resistance of the total respiratory system. Although the responders were fewer and the average threshold values were higher in the elderly, there was no significant differences in the methacholine dose response curve. 2. In vivo and in vitro methacholine dose response relationship was measured in the old guinea pigs (20 to 25 months old) and was compared with that of the young adult guinea pigs. Although no significant differences in the threshold values was observed, the in vivo airway response to the methacholine dose of 1 mg/ml was significantly lower in the old guinea pigs than in the young. The old guinea pig showed small but significant right side shift in the in vitro methacholine dose response relationship. 3. The intra-tracheal instillation of hydrochloric acid to the guinea pig was used as an animal model of aspiration pneumonia. The airway responsiveness was evaluated before and after the instillation. The acid instillation caused the acute and transient bronchoconstriction and the airway responsiveness was markedly increased one hour after the instillation. We conclude that the airway responsiveness may be unchanged or somewhat decreased in the elderly and that the increased airway responsiveness may play a role in the phathologic state such as an aspiration pneumonia.

Adult↗
PubMed1991

A new murine model of aging lung: the senescence accelerated mouse (SAM)-P.

The senescence accelerated mouse (SAM) has recently been characterized as a unique model to investigate age-related disorders, including amyloidosis, cataract, osteoporosis and dementia. However, little is known as to the properties of the lung in these animals. Tobacco smoke is also associated with enhanced loss of elastic recoil and the development of emphysema. We have attempted to examine morphological as well as biochemical changes of the distal lung in SAM-P/2, as the senescence-prone series and SAM-R/1, as the senescence-resistant series. The animals were intermittently exposed to tobacco smoke or air by Hamburg II machines for 5 weeks. Then both groups of animals were killed for histologic and biochemical study. Compared with SAM-R/1, SAM-P/2, even with air exposure, showed a higher value of the mean linear intercept without alveolar wall destruction. It became even greater due to tobacco exposure with emphysematous change. Tobacco exposure accumulated inflammatory cells into alveoli in SAM-P/2, but not in SAM-R/1. Oxygen radical generation by those cells was also higher in SAM-P/2. Analysis of bronchoalveolar lavage fluid in SAM-P/2 after tobacco exposure disclosed increases in albumin content, total protein content and elastase-like activity. There were decreases in the ratio of elastase inhibitory capacity (EIC) to trypsin inhibitory capacity (TIC), contents of glutathione and total free thiol groups. Moreover, SAM-P/2 showed significantly lower EIC/TIC ratio in serum, even with air exposure, than that of SAM-R/1. These results indicate that SAM-P/2 can be a good model for the study of natural evolution of the aging lung as well as its susceptibility to tobacco smoke in the development of emphysema.

Aging↗
PubMed1991

The effect of beta-adrenergic blockade in dilated cardiomyopathy--a questionnaire study in Japan.

The effect of beta-blockade in dilated cardiomyopathy was studied by a questionnaire survey. Thirty-three cases were monitored in whom metoprolol (22 patients, 35.9 +/- 20.4 mg, mean +/- SD), propranolol (four patients, 26.3 +/- 7.5 mg), or other beta-blockers (seven patients) were administered. Four patients died, but no direct relationship was found between administration of beta-blocker and death. The NYHA functional class improved significantly. The mean heart rate decreased from 96/min to 77/min (P less than 0.01). The mean cardiothoracic ratio decreased from 55.6% to 52.1% (P less than 0.01). The mean ejection fraction of the left ventricle measured by echocardiogram increased from 30.4% to 36.9% (P less than 0.01). Exercise tolerance in the treadmill test improved significantly. There was no change in blood pressure, nor were there arrhythmias seen on Holter electrocardiograms. In two patients, congestive heart failure deteriorated after administration of beta-blockers. It is concluded that beta-adrenergic blockade has a beneficial effect in most of the patients with dilated cardiomyopathy.

Adolescent↗
PubMed1991

Intravenous bolus of prednisolone decreases 15-hydroxyeicosatetraenoic acid formation in the rat model of acid aspiration.

BACKGROUND AND METHODS: To test the hypothesis that the effect of steroids on hydrochloric acid aspiration may be involved in the metabolism of eicosanoids, we investigated the effects of an iv bolus of prednisolone on the metabolism of 15-hydroxyeicosatetraenoic acid and 11-dehydrothromboxane B2 (11-dehydro-TxB2) in the rat model of acid aspiration. Wistar rats were randomly selected for three groups and treated with either a) an iv bolus of saline after intratracheal injection of saline (control group), b) an iv bolus of saline after intratracheal injection of acid (acid-saline group), or c) an iv bolus of prednisolone after intratracheal injection of acid (acid-prednisolone group). The concentrations of 15-hydroxyeicosatetraenoic acid and 11-dehydro-TxB2 in bronchoalveolar lavage fluid were measured by radioimmunoassay. RESULTS: The concentration of 15-hydroxyeicosatetraenoic acid in bronchoalveolar lavage fluid of either acid-saline group (804 +/- 129 pg/mL) or acid-prednisolone group (748 +/- 112 pg/mL) was significantly greater than that of the control group (143 +/- 27 pg/mL, p less than .01) 1 hr after the administration. The iv bolus of prednisolone caused a significant decrease in 15-hydroxyeicosatetraenoic acid (acid-saline group 1027 +/- 43 pg/mL; acid-prednisolone group 514 +/- 62 pg/mL; p less than .01) and cell counts of bronchoalveolar lavage fluid 48 hrs after intratracheal injection of acid, while there was no significant change in 11-dehydro-TxB2. CONCLUSION: These findings suggest that corticosteroid administration may contribute to the inhibition of the inflammatory process of lungs after acid aspiration by decreasing the release of 15-hydroxyeicosatetraenoic acid in the distal lung unit.

Animals↗
PubMed1991

Efficacy of oral administration of ofloxacin in lower respiratory tract infections in aged patients with chronic lung disease.

The efficacy of ofloxacin for the treatment of lower respiratory tract infection was evaluated in aged patients with chronic lung disease. Results are the following: improvement of leukocytosis and arterial oxygen tension was observed; peripheral blood cell analysis showed a decrease in natural killer cell counts and in helper/suppressor T cell ratio; superoxide production by peripheral blood white cells was decreased after treatment; interleukin-2 production was rather increased. We concluded that improvement in the immunological parameters indicated the efficacy of ofloxacin for lower respiratory tract infection in aged patients with chronic lung disease.

Administration, Oral↗
PubMed1991

[A clinical evaluation of the inorganic mercurialism--its pathogenic relation to amyotrophic lateral sclerosis].

The pathogenic relation of chronic mercurialism and amyotrophic lateral sclerosis (ALS) was evaluated clinically on 83 ex-mercury workers who were poisoned or exposed to mercury vapor about 18 years ago at one of the biggest mercury mines in Hokkaido, as well as on the causes of 65 expired workers in the cohort. The 83 ex-mercury workers were subdivided into two groups according to severity of mercury poisoning: 31 ex-workers who had been hospitalized for treatment of mercury poisoning and the remaining 52 ex-workers severely exposed to mercury vapor but not hospitalized. Neurologic examinations and measurements of mercury contents in the blood, urine, and hair samples in the 83 cases, failed to disclose any pathogenicity of mercury to ALS. Among these 148 including the 65 deceased cases, no ALS cases were found. Further clinical and epidemiological studies should be required on mercury poisoning as one of the risk factors in the development of ALS, especially in relation to selenium.

Aged↗
PubMed1990

Endothelin-1 stimulates arachidonate 15-lipoxygenase activity and oxygen radical formation in the rat distal lung.

We investigated the effects of intravenous bolus of endothelin-1 on the metabolism of eicosanoids and oxygen radicals in the distal lung unit of the rat. Intravenous bolus of endothelin-1 caused a significant increase in 15-hydroxyeicosatetraenoic acid of bronchoalveolar lavage fluid and oxygen radicals produced by the bronchoalveolar cells. Endothelin-1 exhibited a stimulatory effect on the 15-lipoxygenase activity in the lung homogenate. Thus, endothelin-1 may contribute to the inflammatory and hyperreactive process of lungs, by enhancing the release of 15-hydroxyeicosatetraenoic acid and oxygen radicals in the distal lung unit.

Animals↗
PubMed1990

Circadian rhythms in the number of gastrin cells, DNA synthesizing cells and labelling index of gastrin cells in the antral mucosa of the rat.

Circadian variations of the gastrin cell (G-cell) number, the DNA synthesizing cell (S phase cell) number and labelling index of G-cell in antral mucosa were studied using the simultaneous double immunoenzymatic labelling method of gastrin and bromodeoxyuridine (BrdU) both in fed and 24 h fasted rats. No significant change was observed in the G-cell number. The S phase cell number and labelling index of G-cell showed significant circadian rhythms. Labelling index of G-cell markedly decreased in 24 h fasted rats in comparison to that in fed rats. These results suggest that DNA synthesis in G-cells has a circadian rhythm and that the activity is influenced by food ingestion.

Animals↗
PubMed1990

Reduction of 15-hydroxyeicosatetraenoic acid (15-HETE) in tracheal fluid by high frequency oscillatory ventilation.

The effects of high frequency oscillatory ventilation (HFOV) and conventional mechanical ventilation (CMV) on tracheal secretion were compared in 6 anesthetized dogs. Using a double-balloon endotracheal catheter, 5 ml of saline was instilled into an isolated tracheal segment during HFOV and CMV for 10 min respectively. Two eicosanoids, 15-hydroxyeicosatetraenoic acid (15-HETE) and 11-dehydrothromboxane B2 (11-dehydro-TXB2) were measured by radioimmunoassay in each sample. HFOV (stroke volume: 6 ml/kg, f: 10 Hz, bias flow: 5 l/min) and CMV (stroke volume: 12 ml/kg, f: 15/min) were performed in random sequence and achieved comparable gas exchange. The concentration of 15-HETE in tracheal fluid during HFOV (87 +/- 67 pg/ml) was decreased to less than half of that during CMV (286 +/- 184 pg/ml, P less than 0.05), while there was no significant change of 11-dehydro-TXB2 either in tracheal fluid or in plasma. This reduction of 15-HETE was tended to be enhanced by vagotomy (HFOV: 42 +/- 14, CMV: 120 +/- 103 pg/ml) with the concentration ratio of CMV/HFOV remaining unchanged. HFOV may provide hitherto unrecognized advantage over CMV by reducing airway secretion of 15-HETE, a potent inflammatory mediator.

Animals↗