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Biomedical subjects

T Aikawa

Publications and source records attributed to T Aikawa.

At least 127 records · Page 7Linked to original sources
PubMed1987

Late asthmatic response to Ascaris antigen challenge in dogs treated with metyrapone.

We developed an experimental dog preparation that shows a biphasic bronchoconstriction after allergen exposure. After anesthetization, the dogs were intubated with endotracheal tubes and manually ventilated. Respiratory resistance (Rrs) was measured by the forced oscillation method at 3 Hz. Ascaris suum, diluted from 10(-5) to 10(-2) of the extract, was inhaled during tidal breathing for 5 min. One hour before antigen challenge, 10 dogs received 70 mg/kg of metyrapone (cortisol synthesis inhibitor), and 2 h after antigen challenge 35 mg/kg of metyrapone were injected intravenously. In another 10 dogs, metyrapone was not administered. After the maximal increase in Rrs had been assessed (immediate asthmatic response), Rrs increased again 4 to 6 h after antigen challenge in 8 of the 10 dogs treated with metyrapone (late asthmatic response, 443 +/- 282% mean +/- SD of initial Rrs), which was significantly higher than Rrs 6 h after antigen challenge (124 +/- 41%) in dogs without metyrapone (p less than 0.01). In another 5 dogs, ragweed challenge with metyrapone caused no change in Rrs. Bronchoalveolar lavage at the time of the late response revealed a significant correlation between late asthmatic response and neutrophil accumulation (p less than 0.01) in all dogs. We conclude that cortisol depletion augments the occurrence of the late response. The present dog model may be a useful tool for study of the late response in bronchial asthma.

Airway Resistance↗
PubMed1987

[A case of pseudoxanthoma elasticum showing various heteroptics due to infarction of right parieto-occipital lobe].

A case of pseudoxanthoma elasticum showing various heteroptics due to infarction of the right parieto-occipital lobe was reported. The patient was 48-year-old male. Angiography revealed an obstruction of the right internal carotid artery, aneurysmal dilation of the right posterior communicating artery, and obstructions of the right parieto-occipital artery and calcarine artery. A low density area was found in right occipital lobe by CT. MRI clearly identified lesions in the right cuneus and precuneus. Pseudopsia in the left homonymous quadrantanopsia, various types of visual illusion in the remaining visual field, and moreover, palinopsia were existed. Visual illusion was recognized in the early stage after the onset, while the pseudopsia was recognized about one month after the onset. Both abnormalities tended to improve from the peripheral region with the improvement of the defect in the visual field. Administration of phenytoin resulted in an improvement in the pseudopsia but it resulted in an aggravation in the visual illusion. Thus, the mechanisms of development of this phenomena were thought to be different from each other. It was found by dynamic CT that the blood flow in the primary visual cortex was rather increased in the affected site in comparison with that in the healthy site. It was speculated that the pseudopsia in the defective region of the visual field reflected a pathological repair process represented by a development of the collateral circulation. On the other hand, the visual illusion was thought to originate from visual unstability due to incomplete damage of the visual pathway at the affected site.

Cerebral Infarction↗
PubMed1986

Noonan's syndrome with syringomyelia.

A case of Noonan's syndrome with cervical syringomyelia is presented here representing the second reported instance of such association. A CT of metrizamide myelography revealed a high density in the middle subintradural space in the cervical region below C2. Sensory dissociation was minimal and localized in the left C4. It could not be determined whether this association between syringomyelia and Noonan's syndrome is related or represents a chance.

Adolescent↗
PubMed1986

H1 action of histamine on aldosterone and cortisol secretion by perfused dog adrenal.

The left adrenal of hypophysectomized-nephrectomized dogs was perfused in situ with artificial medium equilibrated with 95% O2-5% CO2. Repeated secretory responses of aldosterone to ACTH and histamine were almost reproducible during 2 h of perfusion, but those of cortisol and corticosterone gradually reduced. The secretion of aldosterone in response to histamine markedly increased at 1 microM and those of cortisol and corticosterone significantly increased at 1 and 10 microM, respectively. The secretory response of aldosterone to 10 microM histamine was comparable with that to 300 microU/ml ACTH, but the secretory responses of cortisol and corticosterone to 10 microM histamine were very much lower than those to 1 microU/ml ACTH. The secretory responses of these three steroids to 10 microM histamine were almost completely depressed by continuous administration of 10 microM pyrilamine maleate, but not abolished by that of 100 microM metiamide. The secretory responses of these three steroids to 10 microM histamine were slightly depressed by continuous infusion of 10 microM methysergide maleate. These results suggest that histamine at pathophysiological concentrations stimulates the secretion of aldosterone markedly, and those of cortisol and corticosterone slightly, via an H1 receptor of adrenocortical cells in the dog.

Adrenal Glands↗
PubMed1986

Central and peripheral airways as determinants of ventilatory function in patients with chronic bronchitis, emphysema, and bronchial asthma.

We studied central and peripheral airways as determinants of ventilatory function in patients with chronic bronchitis (CB), bronchial asthma (BA), and emphysema (CPE), which were identified using the selective alveolobronchogram (SAB) (see reference 14). First, the relationship between SAB and morphologic findings in the airway was examined in 16 autopsy lungs. The irregularity indices of both central (C-II) and peripheral airways (P-II), obtained from SAB, showed a significant correlation with pathologic abnormalities in both airways (p less than 0.01). Second, SAB were obtained in 38 CB, 25 BA, and 62 CPE patients in whom pulmonary function tests were performed. In CB, C-II were significantly correlated with P-II (p less than 0.001). In CB, inspiratory lung resistance (RL) was significantly correlated with P-II (p less than 0.001) and with C-II (p less than 0.01), and FEV/VC% was significantly correlated with P-II (p less than 0.0001) but not with C-II. In BA and CPE, little correlation was observed between any SAB parameter and RL or FEV/VC%. We conclude that the present SAB parameters represent morphometric abnormalities of the central and peripheral airways, and that in CB, peripheral airway abnormalities correlated well with chronic airway obstruction.

Adult↗
PubMed1986

Enhanced endothelial cell proliferation in acute Kawasaki disease (muco-cutaneous lymph node syndrome).

Paired sera from 30 patients with muco-cutaneous lymph node syndrome (Kawasaki disease) were studied for possible effects on human vascular endothelial cells growth in vitro. The majority of sera from acute phase muco-cutaneous lymph node syndrome patients significantly enhanced endothelial cell proliferation more than those from convalescent phase patients, infectious diseases patients, and age-matched normal controls. This stimulation was considered to be specific for EC since muco-cutaneous lymph node syndrome sera did not enhance fibroblast growth more than normal sera. Fractionation of the serum with gel filtration failed to clearly detect the molecular properties of this effect, although both heavy and light material possessed this activity. Extensive search for circulating immune complex in muco-cutaneous lymph node syndrome sera were negative, suggesting that the enhanced endothelial cell proliferation was due to serum components other than immune complexes.

Antigen-Antibody Complex↗
PubMed1986

Cellular analysis in bronchoalveolar lavage fluids in infiltrative and fibrotic stages of idiopathic pulmonary fibrosis.

We performed cellular analysis of bronchoalveolar lavage fluids (BALF) from 20 patients in different stages of idiopathic pulmonary fibrosis (IPF) and compared the results with those from 16 controls and 10 sarcoidosis patients. Patients with IPF were divided into infiltrative and fibrotic groups as diagnosed by transbronchial lung biopsy and chest x-rays. Total cell numbers counted from BALF in IPF patients were not different from those from controls and were lower than in sarcoidosis patients (p less than 0.01). Lymphocytes in BALF were significantly higher in the infiltrative type IPF than in the fibrotic type (p less than 0.05), but there was no significant difference in fibrotic type IPF and control subjects. Numbers of neutrophils and eosinophils counts were not significantly different between infiltrative type and fibrotic type. The neutrophil count in fibrotic type IPF was higher than in control subjects (p less than 0.01) but not in infiltrative type IPF. 67Ga scintiscanning uptake correlated with the lymphocyte population (r = 0.65, p less than 0.01) but with neutrophils. These findings suggest that lymphocytes play a major role in the pathogenesis of the infiltrative type of IPF and that neutrophils are related to the development of fibrotic changes in IPF.

Adrenal Cortex Hormones↗
PubMed1985

Protective effect of fosfomycin against aminoglycoside ototoxicity.

The protective effect of fosfomycin against aminoglycoside (dibekacin)-induced ototoxicity was studied in rats. Rats were injected with 100 or 50 mg/kg of dibekacin with or without 500 mg/kg of fosfomycin for 60 or 120 consecutive days. Inner ear damage appeared to be more reduced histopathologically in animals given both dibekacin and fosfomycin than in animals given dibekacin alone. Similarly, renal damage appeared to be reduced histopathologically and functionally by the combined administration of dibekacin and fosfomycin. The mechanism of reduced ototoxicity may be as follows: fosfomycin inhibits the accumulation of dibekacin in the kidney, and reduces its concentration in the kidney and serum. Consequently, the amounts of dibekacin reaching the inner ear are decreased, and ototoxicity is reduced.

Acetylglucosaminidase↗
PubMed1985

Low ototoxicity and its mechanism of netilmicin.

The ototoxicity and nephrotoxicity of netilmicin were compared with those of dibekacin, kanamycin and amikacin using rabbits. Groups of 5 rabbits each were given doses of 50 or 100 mg/kg of either one of the four drugs for 30 days, and 10 days after the last injection, all animals were prepared for histopathological studies. Results show the least ototoxicity of netilmicin in comparison to the other three antibiotics. It has been concluded that the low ototoxicity of netilmicin is due not to its lack of accumulation in the perilymph but to its low toxicity to the hair cells.

Amikacin↗
PubMed1985

Reduction of cisplatin ototoxicity by fosfomycin in animal model.

The protective effect of fosfomycin against cisplatin-induced ototoxicity was studied in rats. Sixty-four Fischer rats were injected intravenously with daily doses of 1, 2, 5, and 10 mg/kg of cisplatin with or without 300 mg/kg of fosfomycin for a varying period from 1 to 10 days. The total dose of 10 mg/kg of cisplatin was given equally in all animals. Inner ear damage appeared to be more reduced histopathologically in animals given both cisplatin and fosfomycin than in animals given cisplatin alone. Similarly, renal damage appeared to be reduced histopathologically and functionally by the combined administration of cisplatin and fosfomycin.

Animals↗
PubMed1984

Relationship between ototoxicity of aminoglycoside antibiotics and their transferability into inner ear fluids.

The purpose of this study is to clarify the question whether the difference of severity of ototoxicity induced by the aminoglycoside antibiotics depends on the difference of quantity of transferability into inner ear. Aminoglycoside antibiotics (tobramycin, kanamycin, netilmicin and ribostamycin) were injected for 30 consecutive days to rabbits. The relationship between the severity of hair cell damage and concentration of antibiotics in perilymph was investigated. The drug concentration in the perilymph was determined by the bioassay method, and using the surface preparation technique the hair cell damage was observed under a phase contrast microscope. It was concluded that the difference of severity of ototoxicity induced by the aminoglycoside antibiotics is due to the difference of their own toxicity to hair cells but not to the difference of their transferability into the perilymph.

Aminoglycosides↗