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Biomedical subjects

N Sakurai

Publications and source records attributed to N Sakurai.

At least 127 records · Page 7Linked to original sources
PubMed1990

A computer simulation of the creep process of the cell wall using stress relaxation parameters.

The stress relaxation of the cell wall of pea plants was measured and viscoelastic parameters were obtained according to the stress-relaxation analysis developed by Yamamoto et al. (Plant & Cell Physiol. 1970). The creep process of the cell wall was simulated by a numerical integration using stress-relaxation parameters, because the direct conversion of the stress relaxation process to the creep is impractical. In the conversion, a personal computer was programmed for the Maxwell viscoelastic model with a compiler language. Cell wall creep was measured with a specially constituted apparatus and compared with that calculated by the simulation process. The results suggested that the creep can be reproduced by a computer simulation using the stress-relaxation parameters. Both creep and stress-relaxation properties of plant cell walls can be analyzed by using a single model.

Cell Wall↗
PubMed1990

[In vitro synergism of two-drug combinations among cefamandole, flomoxef and imipenem against MRSA].

First of all, vancomycin (VCM) showed good antimicrobial activity against Staphylococcus aureus including methicillin-sensitive and -resistant strains. MIC90 of VCM was 1.56 micrograms/ml. Effects of different 2-drug combinations among cefamandole (CMD), flomoxef (FMOX) and imipenem (IPM), and activity of VCM alone were examined in vitro against 5 clinical isolates of methicillin-sensitive S. aureus (MSSA) and 22 isolates of methicillin-resistant S. aureus (MRSA). In a checkerboard study, synergism was observed against 4 strains of the 5 MSSA and all 22 strains of the MRSA with IPM and CMD, FMOX and IPM, and FMOX and CMD combinations. Mean MICs of these combinations were as low as one-fourth to one-tenth as those of individual drugs.

Cefmetazole↗
PubMed1989

Combined effects of vibration and noise on palmar sweating in healthy subjects.

The combined effects of vibration and noise on palmar sweating were studied experimentally in healthy subjects. Ten subjects were exposed to vibration at an acceleration of 100 m.sec-2 root mean square at a frequency of 125 Hz, a noise level of 105 dB(A) at a frequency of 1000 Hz and both stimuli together. Vibration was applied to the right hand and noise to both ears from headphones. Palmar sweating was measured by the ventilated capsule method. Vibration caused a marked increase in palmar sweating of the right hand directly exposed to vibration and also of the left hand not exposed to vibration. Simultaneous vibration and noise caused a greater increase in palmar sweating than by each of the factors separately. The combined effects tended to be greater in subjects who were more susceptible to vibration or noise.

Adult↗
PubMed1989

Culm strength of barley : correlation among maximum bending stress, cell wall dimensions, and cellulose content.

Grass culms are known to differ in breaking strength, but there is little physicochemical data to explain the response. The fourth internode of four brittle and two nonbrittle barley (Hordeum vulgare L.) strains were used for physical and chemical studies of culm strength. Inner and outer culm diameters of brittle strains (3.6 +/- 0.2 and 5.0 +/- 0.1 millimeters) were not significantly different from those of nonbrittle strains (3.9 +/- 0.2 and 5.2 +/- 0.2 millimeters). Maximum bending stress, at which the culm was broken, was 192 +/- 34 g/mm(2) for brittle and 490 +/- 38 g/mm(2) for nonbrittle strains. Wall thickness and cell dimensions of epidermal, sclerenchyma, and parenchyma cells were measured in culm cross sections. The area of cell wall per unit cell area for each tissue was significantly correlated with the maximum bending stress (r = 0.93 for epidermis, 0.90 for sclerenchyma, and 0.84 for parenchyma). Cell walls of brittle culms had 6 to 64% as much cellulose content as those of nonbrittle culms. Maximum bending stress correlated significantly with cellulose content of the cell walls (r = 0.93), but not with the contents of noncellulosic compounds. The lower cellulose content of the brittle culm was significantly correlated with brittleness.

Journal Article↗
PubMed1989

Reaction times of movement preparation in patients with Parkinson's disease.

We studied the onset of preparatory postural responses and subsequent voluntary movements by measuring soleus muscle activities in the standing position in 20 patients with Parkinson's disease. We measured the postural response in preparing to rise on tiptoe as the onset of the premotion silent period (PMSP). Our patients showed no delay when compared with age-matched healthy controls, but did show a significant delay in the onset of voluntary movement. The elongated PMSP (increased duration of the preparatory postural adjustments) was related to the severity of bradykinesia. Results indicate that the conventional reaction time is increased in patients with Parkinson's disease, even though there is no delay of central processing for the preparation of voluntary movements, and that there is bradykinesia of involuntary postural movements.

Adult↗
PubMed1989

[Studies on chemical protectors against radiation. XXVI. Protective effect of various extracts on crude drugs on skin injury induced by X-irradiation].

The protective potency against skin injury on mice induced by X-irradiation was studied by use of 72 extracts of crude drugs. The protective potency was determined according to the degrees on skin injury after irradiation of 1100R, 30 k Vp soft X-ray. As a result of these study, 16 kinds of crude drugs such as Rosae Fructus, Aloe arborescens (Herba), Citri Leiocarpae Exocarpium, Schizonepetae Spica, Evodiae Fructus, Bupleuri Radix, Corni Fructus, Perillae Herba, Anemarrhenae Rhizoma, Menthae Herba, Trapae Fructus, Angelicae Dahuricae Radix, Sinomeni Caulis et Rhizoma, Ephedrae Herba, Acer nikoense (Cortex), Forsythiae Fructus, revealed protective potencies on skin injury.

Animals↗
PubMed1988

Mycoplasma pneumoniae and other pathogens in the aetiology of lower respiratory tract infections among Japanese children.

The causes of lower respiratory tract infections in 1544 children attending a Japanese hospital over a period of 7 years were investigated. Both cultivation and two serological techniques were used to detect Mycoplasma pneumoniae whereas viral involvement was investigated only by serology. Pathogens were identified in 52% of 1175 patients with pneumonia and 36% of 369 patients without pneumonia. Mycoplasma pneumoniae infection was specifically diagnosed in 414 (26.8%) of the 1544 patients. Respiratory syncytial virus (RSV) was dominant in children up to 2 years of age. By the age of 3 years, M. pneumoniae was equalling it in incidence and became the main pathogen in older groups. It is suggested that M. pneumoniae may be more important in the 3-6 years age group than hitherto suspected. These observations may influence the choice of antibiotics for treating lower respiratory tract infections in childhood.

Adenovirus Infections, Human↗
PubMed1988

Isolation of Mycoplasma pneumoniae from children with lower-respiratory-tract infections.

The prevalence and clinical pictures of Mycoplasma pneumoniae infections among children were studied using culture and serological techniques. The isolation rate was 22% (195 of 885) in pneumonic patients and 11% (66 of 600) in non-pneumonic patients. In patients three years of age or less, M. pneumoniae was isolated at the same rate from febrile and afebrile cases and from wheezy and non-wheezy cases. In older patients, however, M. pneumoniae was frequently isolated from febrile but non-wheezy cases. A peak in the number of the positive isolates was found in patients who were four years old. The peak number of M. pneumoniae infections at age four was confirmed serologically. This peak was in patients who were younger than those previously reported.

Adolescent↗