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Biomedical subjects

K Hanada

Publications and source records attributed to K Hanada.

At least 325 records · Page 18Linked to original sources
PubMed1986

Restricted access to natural mother shifted endogenous rhythm of rat pups.

For further investigation of the role of rat dams in setting the phase of pups' endogenous circadian rhythm, periodic maternal deprivation experiments were performed. Access of intact original mothers to blinded pups was restricted to light phase (L-Suckling pups) or dark phase (D-suckling pups) under 12-12 h light-dark alternation throughout the nursing period. Free-running patterns of drinking and corticosterone rhythms were determined for 3 consecutive weeks after weaning. In each determination of the rhythm, water consumption and corticosterone levels were measured every 4 hr. Both rhythms were clearly observed in both L- and D-suckling pups. Acrophase of water intake rhythm at 5 weeks of age in L-suckling and D-suckling groups were 0758 h and 1954 h while those of corticosterone rhythm were 0143 h and 0948 h respectively. Reversed phase relationship of rhythms between L- and D-suckling groups were observed throughout the period examined. These results indicate that suckling can act as a Zeitgeber for the endogenous rhythm of pups.

Age Factors↗
PubMed1986

In vitro and in vivo inhibition of cysteine proteinases by EST, a new analog of E-64.

E-64 isolated from a culture of Aspergillus japonicus is a specific inhibitor of cysteine proteinases. E-64-c, a synthetic analog of E-64, was effective in model animals of muscular dystrophy only when it was given intraperitoneally and by means of osmotic minipump. It showed no effects due to its low absorbability from intestine when it was administered orally. EST, the ethyl ester of E-64-c, was expected to be readily absorbed through intestinal membrane, since it is more lipophilic than E-64-c. Both EST and E-64-c have a high specificity to cysteine proteinase similar to E-64 but E-64-c was 100 to 1000 times stronger than EST in in vitro cathepsin inhibition. However, EST was stronger than E-64-c in cathepsin inhibition when given orally. The cathepsin B&L activities (whole activities of cathepsins B and L) in the skeletal muscle, heart and liver of hamsters were strongly inhibited soon after oral administration of 100 mg/kg body weight of EST. The inhibition continued for at least 3 h and then disappeared gradually. E-64-c was found in plasma of hamster treated with EST, but unchanged EST was not found. These results suggested that EST was converted to E-64-c, a more active form, during the permeation through intestinal membrane. The conversion of EST to E-64-c was also indicated by the absorption experiment using in situ loop method. EST was thus shown to be useful as an oral drug and expected to be effective in therapeutic trials using model animals.

Animals↗
PubMed1986

Degradation of myocardial structural proteins in myocardial infarcted dogs is reduced by Ep459, a cysteine proteinase inhibitor.

The purpose of this study is to clarify whether cysteine proteinases play an important role in the degradation of myocardial proteins in the infarcted tissue. We studied the effects of a cysteine proteinase inhibitor, Ep459, on degradation of cardiac structural proteins caused by ischemia due to coronary artery ligation for 24 h. Proteolytic effects of purified cysteine proteinases on isolated cardiac tissue were also examined. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, degradation of cardiac structural proteins, particularly of myosin heavy chain, alpha-actinin and troponin-I was observed in the infarcted tissue. Treatment with Ep459 significantly reduced protein degradation and total activity of cathepsins B and L in the infarcted tissue, compared with the findings in the untreated group. The electrophoretic pattern of the infarcted myocardium was similar to that of myofibrillar proteins degraded by cathepsins B and L. These results suggest that cysteine proteinases, particularly cathepsins B and L, are involved in degradation of myofibrillar proteins in myocardial infarction.

Animals↗
PubMed1986

[Antibacterial activity of cephem antibiotics against isolates from clinical specimens at the Yokohama City University Hospital].

Minimum inhibitory concentrations (MICs) of cephem antibiotics against 405 strains belonging to 17 species of clinical isolates were investigated using the standard method of the Japanese Congress of Chemotherapy. The results obtained are summarized below. Cephem antibiotics showed weak antibacterial activities against Enterococcus sp., B. fragilis and S. marcescens. S. pneumoniae, S. agalactiae, E. coli, K. pneumoniae and P. mirabilis were susceptible to cephem antibiotics. Cephem antibiotics of the 1st and the 2nd generations showed weak antibacterial activity against Citrobacter sp. and E. cloacae, while cephem antibiotics of 3rd generation had a good antibacterial activity against these species. Cephem antibiotics of the 2nd and the 3rd generations showed high antibacterial activity against H. influenzae and indole positive Proteus group. Cefoperazone showed high antibacterial activity against P. aeruginosa. Resistance to latamoxef, ceftizoxime and cefoxitin was observed among Staphylococcus sp., while the MICs of other antibiotics against Staphylococcus sp. were fairly low. Number of strains resistant to the 3rd cephem antibiotics seems to be increasing because the 3rd generation of cephem antibiotics have been used frequently. Further investigation will be required on resistant organism to these antibiotics including beta-lactamase producing strains.

Cephalosporins↗
PubMed1985

Identification of proline carrier in Escherichia coli K-12.

Proline carrier, a product of the putP gene of Escherichia coli, was identified as a 35 kDa cytoplasmic membrane protein by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Its identification was based on the following evidence: First, the density of the band corresponding to a 35 kDa protein correlated with the proline-binding activity of cytoplasmic membranes from putP-deficient and putP-amplified strains. Second, by the differential labeling method, the 35 kDa protein was specifically labeled with radioactive N-ethyl-maleimide. The 35 kDa protein was found to aggregate on heat treatment and to show abnormal mobility on SDS-PAGE.

Amino Acid Transport Systems, Neutral↗
PubMed1985

A new method for finite element simulation of orthodontic appliance-teeth-periodontium-alveolus system.

This paper describes a new simulation method to analyze the initial behavior of the total system comprising orthodontic appliance, teeth, and their supporting structures. It is based on a finite element method which additionally takes account of a rotational degree of freedom. Beam and rod elements are used for finite element idealization of orthodontic appliance. Through spring elements it is connected with the teeth supported by the alveolar structures. The technique of 'initial strain' is introduced so as to analyze the effects of a gable bend and activation on the force system which is delivered by the orthodontic appliance. As compared with the photoelastic technique hitherto used, this method serves to investigate systematically and quantitatively the initial aspect of orthodontic tooth movement.

Alveolar Process↗
PubMed1985

Direct radioimmunoassay of cortisol in saliva and its application to the dexamethasone suppression test in affective disorders.

In order to perform the dexamethasone suppression test (DST) with saliva as an alternative to serum, we assayed directly the cortisol concentrations in 25 microliters saliva samples, using a commercial radioimmunoassay kit for serum cortisol with minor modifications. Cortisol in saliva showed a diurnal rhythm parallel to that of cortisol in serum samples collected simultaneously. Saliva cortisol levels increased significantly after ACTH injection, but with a 60 min delay in reaching their peak compared to peak serum cortisol levels. The increase in saliva cortisol was five-fold, while that in serum was two-fold. Saliva cortisol levels continued to increase in some subjects while serum total cortisol levels already had begun to decline. In those subjects, the correlation of saliva with serum cortisol was greater when a quadratic curve was fitted than when calculated for a linear correlation. Considerable variation was observed for within-subject correlations, ranging from + 0.48 to + 0.999. The DST with saliva sample collection was performed on 43 inpatients with affective disorders. Sensitivity, specificity and diagnostic confidence of the DST for major depressive episode with melancholia were 33%, 91%, and 78%, respectively, at the criterion value of 0.3 microgram/100 ml for saliva cortisol, which are similar to those most often reported for the DST with serum cortisol determination. These results indicate that saliva cortisol levels do not always parallel serum cortisol levels and thus are not an unequivocal substitute. The findings for the DST in psychiatric patients, however, support the practical clinical usefulness of saliva cortisol measurements.

Adrenocorticotropic Hormone↗
PubMed1985

[Development of a photoperiod-controllable clean rack for rats: circadian rhythms of water intake and blood corticosterone levels].

We have experimentally developed a photoperiod-controllable clean rack for SPF rats. The effectiveness of this clean rack in preventing the infection was attested to by the fact that the SPF rats and nude mice housed in this rack maintained SPF conditions after six months. And we investigated circadian rhythms of water intake and blood corticosterone levels in rats kept in the rack under various lighting conditions. Both rat groups under diurnal and reversed lighting conditions manifested significant increase in both water and blood corticosterone levels, showing a reversed phase relationship of the circadian rhythms between the two groups. These facts indicate the usefulness of the rack newly developed in the studies on circadian rhythms, reproductive physiology and behavior.

Animals↗