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Biomedical subjects

M Kondo

Publications and source records attributed to M Kondo.

At least 919 records · Page 51Linked to original sources
PubMed1989

A fundamental study of rhinomanometry and its clinical application to objective evaluation.

We measured differential pressure and airflow at constant flow through a cylinder which had a variable aperture in its central portion, by means of a Rhinorheograph MPR-1100 in order to obtain a turbulent coefficient "n" experimentally in the equation R = delta P/Vn. Between of 1.0-5.0 cm H2O (not equal to 100-500 Pa) pressure, the coefficient "n" was distributed between 1.01-2.80 with a mean value of 2.02 (+/- 0.36), and resistances calculated from the equation R = delta P/Vn were almost the same value at each differential pressure. We applied this coefficient to 95 adult patients referred to our nasal airflow laboratory in Toronto, and found the equation R = delta P/V2 to be quite suitable for clinical assessment.

Adolescent↗
PubMed1989

Influence of microinjection of glucagon into the amygdala on hepatic acetate metabolism in rabbits.

Glucagon was injected directly into the medial amygdala (AMYG) of rabbits, and changes in hepatic acetate metabolism were studied. The injection of 3 ng glucagon into the AMYG of intact rabbits increased the rates of 14C transfer from 14C-1-acetate into CO2, glucose, ketone bodies, cholesterol ester, free fatty acids and phospholipids but decreased those of 14C transfer into triglyceride. However, the glucagon injection into the AMYG of rabbits with lesions of stria terminals or into the parietal cortex of intact rabbits had no effects on the hepatic acetate metabolism. These observations support the hypothesis that the AMYG is a part of the glucagon-sensitive brain regulator system in the hepatic acetate metabolism.

Acetates↗
PubMed1989

Emergence of methicillin-resistant clones from cephamycin-resistant Staphylococcus aureus.

Staphylococcus aureus strains specifically resistant to cephamycin antibiotics have been found among recent clinical isolates. These strains formed penicillin-binding protein (PBP) 2' and became phenotypically resistant to methicillin after induction with cefoxitin. Other cephamycin-type antibiotics also induced methicillin-resistance, whereas non-cephamycin-type cephalosporins such as cefmenoxime and ceftizoxime did not do so. The clones that constitutively synthesized PBP 2' arose from the cephamycin-resistant strains at a frequency of 10(-5). They were indistinguishable from clinically isolated methicillin-resistant S. aureus (MRSA). Cephamycin-resistant S. aureus may be a source for emerging MRSA.

Bacterial Proteins↗
PubMed1989

Role of outer coat in resistance of Bacillus megaterium spore.

The outer coat fraction (OC-Fr) of Bacillus megaterium ATCC 12872 spore was isolated as a resistant residue after alkali extraction, sonic treatment, and pronase digestion of the spore coat preparation, and its backbone structure was determined by chemical analysis to be composed of galactosamine-6-phosphate (GalN-P) polymers with polypeptides and calcium. OC-Fr was not fully solubilized after ordinary acid hydrolysis. OC-Fr was insensitive to all hexosaminidases tested, and moreover, an isolated fragment, a pentamer of GalN-P, was also resistant to lysozyme and hexosaminidases even after N-acetylation, being sensitive to them to some extent after dephosphorylation. Molecular sieving experiments revealed that the outer coat limited the entry of compounds with a molecular weight of more than 2,000. Exchange of the metal on the spore surface also influenced the heat resistance. Spores of OC-Fr-deficient mutants were less resistant but were still much more resistant than the vegetative cells. These results suggest that the outer coat protects the contents of the spore against chemical, physical and enzymatic treatments owing to the chemical structure itself, composed mainly of GalN-P polymers, and the molecular sieving effect.

Bacillus megaterium↗
PubMed1989

Electrophysiological studies of intermittent claudication in lumbar stenosis.

To clarify the pathophysiology of intermittent claudication in 37 patients with lumbar spinal stenosis, neural function was evaluated by examining somatosensory evoked potentials (stress-SEPs), and nerve action potentials (stress-NAPs) before and after walking stress. It was shown preoperatively that the stress-SEPs became abnormal immediately after walking in 31 of 37 patients. In seven of nine operated patients, the assessment clearly shows that SEPs had reverted to normal after surgery. The present method is noninvasive, simple in technique, painless, and safe, a procedure therefore that is useful as the initial step in the diagnosis and treatment of patients with lumbar canal stenosis. It also may help to differentiate neurogenic from vascular intermittent claudication.

Adult↗
PubMed1989

Decreased leukocyte ferrochelatase activity in erythropoietic protoporphyria.

We studied the porphyrin metabolism of a 7-year-old Japanese boy with erythropoietic protoporphyria (EPP) and his family members. Leukocyte ferrochelatase activity was markedly decreased in this patient, being approximately 12% of the mean value of normal controls (4 aged-matched healthy boys). In contrast, leukocyte delta-aminolevulinic acid (ALA) synthase activity was normal. The free protoporphyrin content of erythrocytes was greatly increased (4.3 mg/100 ml RBC), while erythrocyte ALA dehydratase and porphobilinogen (PBG) deaminase activities were 1.7- and 2.2-fold of respective control values. A survey of his family revealed that 12 of 19 members probably had manifest EPP or were EPP carriers. These results suggest that, in EPP, there might be an inherited impairement of ferrochelatase activity which gives rise to an elevation of erythroblast ALA dehydratase and PBG deaminase activities to compensate for a resultant decrease in heme production.

5-Aminolevulinate Synthetase↗
PubMed1989

Characterization and deposition of the proteins in the outermost layer of Bacillus megaterium spore.

It was proved that three spore coat proteins of 48, 36, and 22 kDa (P48, P36, and P22) were the components of the outermost layer (OL) of Bacillus megaterium ATCC 12872 spore by analysis of the isolated OL. And it was indicated that these proteins were deposited not by disulfide bond, but by ionic and/or hydrophobic bonds on the spore. Among them, P36 and P22 were expected to be located on the very surface of the spore by immunological analysis. In the OL deficient mutant of B. megaterium ATCC 12872, MAE05, whose spore was lacking in these OL proteins and galactosamine-6-phosphate polymer, both P36 and P22 were present in the mother cell cytoplasm and deposited on the forespores, but they disappeared with the lysis of mother cells. An OL protein-releasing factor having proteolytic activity was detected in the culture supernatant at the late sporulating stage of both the wild-type and the mutant strains. But the factor could not act on the proteins of the mature spores and the forespores at t10 (tn indicates n hr after the end of exponential growth) of the wild-type strain. Moreover, P36 and P22 were found in the spores of a revertant of MAE05 which could form galactosamine-6-phosphate polymer, suggesting that this sugar polymer played the role in protecting the OL proteins against the protease-like substance after the deposition.

Bacillus megaterium↗
PubMed1989

Isolation of the saprophytic strain of MC-3 and participation of the cell surface structure in predation.

From a predatory bacterium, MC-3, a mutant strain which lost predation ability was isolated by chance selection. Biological properties of the mutant were the same as the parent except only saprophytic property. Properties of the parent and the mutant strains of MC-3, such as bacteriolytic activity of the culture supernatant, digestion of peptidoglycan of the host bacteria, and growth by utilizing the host cells or their cytoplasmic substances, suggested that cell surface structure of the host cell plays an important role in predation and host specificity.

Bdellovibrio↗
PubMed1989

Effect of cAMP on ciliary function in rabbit tracheal epithelial cells.

To study the effect of adenosine 3',5'-cyclic monophosphate (cAMP) on respiratory ciliary activity, we measured ciliary beat frequency (CBF) of rabbit tracheal epithelium by a photoelectric method in response to cAMP analogues and agents that can increase endogenous cAMP production. Addition of 8-bromo-cAMP dose dependently enhanced CBF, with the maximal increase and the concentration necessary to produce a half-maximal response (KD) being 31.0 +/- 3.4% (SE) (P less than 0.001) and 3.2 +/- 1.5 x 10(-7) M, respectively. Other structurally dissimilar cAMP analogues dibutyryl cAMP and chlorophenylthio-cAMP likewise caused increases in CBF. The phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine and the adenylate cyclase stimulator forskolin also augmented CBF in a dose-dependent fashion and were accompanied by the increases in intracellular concentrations of cAMP. Ciliary discoordination was not observed in any of the experiments. These results suggest that cAMP may accelerate mucociliary clearance through the activation of ciliary motility and that intracellular cAMP levels appear to be an important determinant for the lung mucociliary transport functions.

1-Methyl-3-isobutylxanthine↗
PubMed1989

Adenosine-mediated cyclic AMP-dependent inhibition of ciliary activity in rabbit tracheal epithelium.

We wished to determine whether adenosine, a purine nucleotide, modulates activity of respiratory cilia and, to this end, we studied cultured rabbit tracheal epithelium in response to adenosine and related substances in vitro. Ciliary beat frequency (CBF) as determined by a photoelectric method was depressed by adenosine (10(-3) M), the maximal decrease from the baseline value (965 +/- 29 beats/min, mean +/- SE) being 31.6 +/- 5.0% (p less than 0.001). The adenosine A2-receptor agonist N-ethylcarboxamide adenosine had only a small effect on ciliary activity, whereas other adenosine analogs elicited decreases in CBF in a dose-dependent fashion. The order of potency of cilia-inhibitory action was N-cyclohexyladenosine (an agonist for adenosine A1-receptor) greater than phenylisopropyladenosine greater than adenosine greater than N-ethylcarboxamide adenosine. Intracellular cyclic AMP (cAMP) levels were decreased by 10(-3) M adenosine from 39.2 +/- 6.5 to 25.3 +/- 4.8 pM/mg protein (p less than 0.05). The effect of adenosine on CBF was enhanced by dipyridamole, an adenosine uptake inhibitor, and by deoxycoformycin, an adenosine deaminase inhibitor. The adenosine-induced decreases in CBF and cAMP content were reversed by 8-phenyltheophylline, an adenosine receptor antagonist. These results suggest that there is an adenosine A1-receptor on rabbit tracheal epithelium that inhibits adenylate cyclase, which may result in the impairment of respiratory ciliary activity, and that adenosine-induced ciliary inhibition may be modulated by adenosine uptake and its catabolism by airway epithelial cells.

Adenosine↗
PubMed1989

A quantitative structure-activity relationship for antitumor activity of long-chain phenols from Ginkgo biloba L.

With the aim of obtaining compounds with strong antitumor activity, a quantitative structure-activity relationship (QSAR) of antitumor phenolic compounds (long-chain phenols) was derived using the Hansch-Fujita equation. The ED50 values against Chinese hamster V-79 cells were analyzed in terms of log P as the hydrophobic parameter and the energy of the lowest unoccupied molecular orbital (ELUMO) calculated by using the modified neglect of differential overlap (MNDO) method as the electronic parameter, by means of multiple regression analysis. It was found that the activities mainly depended on log P (an optimum log P of 8.3) and a low-lying ELUMO value. 4-Undecylcatechol, selected on the basis of the above results, exhibited strong antitumor activity against Sarcoma 180 ascites and P-388 lymphocytic leukemia.

Animals↗
PubMed1989

Lesions of the hypothalamic paraventricular nucleus and norepinephrine turnover in rats.

The effects of bilateral lesions of the hypothalamic paraventricular nuclei (PVN), of rats with a mean weight of 260 g body, on eating habits and body weight, as well as on sympathetic nervous system (SNS) activity in interscapular brown adipose tissue (IBAT) were investigated. In 59 of 131 Sprague-Dawley female rats, PVN lesions resulted in hyperphagia and obesity. Although lesions were considered successful when more than 50% of the PVN was destroyed histologically, such lesions were observed in 35.9% (47/131) of all lesioned rats and all of these 47 rats were obese. Therefore, in this study, these 47 rats which were confirmed histologically, were designated as "PVN-lesioned rats". Plasma insulin levels in these 47 PVN-lesioned ats were more than double those of the controls. However, no significant differences were observed between plasma glucose levels in PVN-lesioned and control groups. Norepinephrine turnover, a reliable indicator of SNS activity, in IBAT, heart and pancreas was similar in PVN-lesioned and sham-operated control animals, even under contrasting conditions of feeding (ad libitum and fasting) and temperature (22 degrees C and 4 degrees C). It is concluded that PVN lesions produce hyperphagia, obesity and hyperinsulinemia in rats with an average body weight of 260g without affecting the SNS activity in IBAT, heart or pancreas.

Adipose Tissue, Brown↗
PubMed1989

Effects of exercise training on brown adipose tissue thermogenesis in ovariectomized obese rats.

The effect of exercise training on brown adipose tissue (BAT) thermogenesis was studied by measuring cytochrome oxidase activity, as a marker of mitochondrial abundance, mitochondrial guanosine-5'-diphosphate (GDP) binding, as an indicator of thermogenic activity and oxygen consumption in BAT in ovariectomized (OVX) obese rats and sham-operated rats. Six-week exercise training significantly suppressed body weight gain in OVX rats to the level of sedentary control rats, although food intake in exercise trained OVX rats increased more than in the sedentary OVX rats. Exercise training increased cytochrome oxidase activity, mitochondrial GDP binding and oxygen consumption in BAT in OVX rats, which were reduced in a sedentary condition, as well as in the control rats. These results suggest that exercise training potentiates BAT thermogenesis, which may contribute to the reduction of body weight in OVX obese rats.

Adipose Tissue, Brown↗
PubMed1989

Overt diabetes induced by overeating in neonatally STZ-treated impaired glucose tolerant mice: long-term follow up study.

This study has investigated the effect of a long period of overeating on the glycemic control and pancreatic beta-cell function in neonatally streptozocin treated impaired glucose tolerant mice. Neonatally streptozocin (60 mg/kg) treated male ICR mice with 150-200 mg/dl of fed blood glucose levels were divided into two groups at 6 weeks of age. One group was maintained on a cafeteria diet (SZC) and the other on ordinary mouse chow (SZ) until 30 weeks of age. Normal male ICR mice were divided into a cafeteria diet group (CC) and an ordinary chow group (Cont). SZC and CC consumed 134-124% of the caloric intake in SZ and Cont throughout the study. Marked elevation of the fed blood glucose level was observed and the glucose tolerance was progressively impaired in SZC. On pancreas perfusion at 30 weeks of age, insulin secretion to 30 mM glucose in SZC was significantly decreased compared with that in SZ. That in CC was slightly decreased compared with that in Cont. The pancreatic insulin concentration in SZC was significantly less than that in SZ. We conclude that chronic hyperglycemia, induced by the long period of overeating, accelerated the selective loss of beta-cell sensitivity to glucose. Even in normal mice that did not have marked hyperglycemia, insulin secretion to glucose was suppressed, probably by chronic stimulation of the beta-cell due to the long period of dietary excess.

Animals↗
PubMed1989

The role of insulin in norepinephrine turnover and thermogenesis in brown adipose tissue after acute cold-exposure.

The role of insulin in norepinephrine turnover (NE) and thermogenesis in brown adipose tissue (BAT) after acute cold-exposure was studied using streptozocin (STZ)-induced diabetic rats. NE turnover was estimated by the NE synthesis inhibition technique with alpha-methyl-p-tyrosine. BAT thermogenesis was estimated by measuring mitochondrial guanosine-5'-diphosphate (GDP), cytochrome oxidase activity and mitochondrial oxygen consumption in BAT at an ambient temperature of 22 degrees C and during a six-hour cold-exposure at 4 degrees C. In insulin-deficient diabetic rats, the NE turnover, mitochondrial GDP binding, cytochrome oxidase activity and mitochondrial oxygen consumption in BAT at 22 degrees C were significantly reduced, compared with those of control rats. Treatment of STZ-induced diabetic rats with insulin prevented a decrease in NE turnover and BAT thermogenesis. Acute cold-exposure increased the NE turnover of BAT in insulin-deficient diabetic rats. The BAT thermogenic response to acute cold-exposure, however, did not occur in insulin-deficient diabetic rats. These results suggest that insulin is not essential in potentiating NE turnover in BAT after acute cold-exposure, but is required for cold-induced thermogenesis.

Adipose Tissue, Brown↗
PubMed1989

Effects of cigarette smoke on norepinephrine turnover and thermogenesis in brown adipose tissue in MSG-induced obese mice.

To clarify whether cigarette smoke stimulates the sympathetic nervous system (SNS) and thermogenesis in interscapular brown adipose tissue (IBAT), we measured norepinephrine (NE) turnover, an indicator of SNS activity, guanosine-5'-diphosphate (GDP) binding, a thermogenic indicator, and oxygen consumption in IBAT in monosodium-L-glutamate (MSG)-induced obese and saline control mice following a two-week exposure to cigarette smoke. Cigarette smoke significantly increased NE turnover, GDP binding and oxygen consumption in IBAT, and significantly reduced body weight in MSG obese mice as well as in control mice. However, food intake was unchanged in the MSG group. These results suggest that cigarette smoke stimulates NE turnover and thermogenesis in BAT, which contribute to the mitigation of obesity.

Adipose Tissue, Brown↗
PubMed1989

Effect of acute cold-exposure on norepinephrine turnover and thermogenesis in brown adipose tissue and metabolic rate in MSG-induced obese mice.

Mice treated neonatally with monosodium-L-glutamate (MSG) are known to develop into obese adults without hyperphagia, which are characterized by the reduced levels in the resting metabolic rate (RMR) and the thermogenesis of brown adipose tissue (BAT) in the thermoneutral environment. The present study revealed that an acute cold-exposure (5 degrees C, 1 h) of these animals resulted in the increase in norepinephrine turnover and mitochondrial-5'-diphosphate (GDP) binding in the interscapular BAT as well as the guanosine RMR, suggesting a normal thermogenic responsiveness of BAT to cold.

Adipose Tissue, Brown↗