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Biomedical subjects

H Nishimoto

Publications and source records attributed to H Nishimoto.

At least 91 records · Page 5Linked to original sources
PubMed1979

Purification and some properties of deoxyribonuclease whose synthesis is controlled by gene 49 of bacteriophage T4.

An enzyme which specifically cleaves very-fast-sedimenting DNA of bacteriophage T4 is synthesized after infection of T4, and its synthesis is controlled by gene 49 [1,2]. This enzyme has been proved to be a DNase [2]. We have purified this DNase 3000-fold from extracts of E. coli infected with T4. The purified preparation was practically free from other DNases, and the DNase activity was not detectable in cells infected with a mutant defective in gene 49. The enzyme activity from cells infected with a temperature-sensitive mutant of gene 49 was also temperature-sensitive, suggesting strongly that gene 49 is a structural gene of the DNase. The molecular weight of the wild-type enzyme was estimated to be 50 x 10(3) by gel filtration chromatography. The purified DNase did not cleave native and denatured DNAs of T3 and T4, but cleaved renatured T3 DNA with enzymatically fragmented T3 DNA, indicating that gaps in the DNA duplex are structures susceptible to the DNase. Cleavage of the hybridized T3 DNA occurred when the fragmented DNA was phosphorylated at either the 3' or 5'-strand termini.

Deoxyribonucleases↗
PubMed1979

Suppression of mixed lymphocyte reaction by progesterone and estradiol-17beta.

The effects of estrone, estradiol-17beta, estriol, testosterone, progesterone, and 20alpha-dihydroprogesterone on incorporation of 3H-thymidine into cultured lymphocytes from normal men and nonpregnant women in response to allogeneic stimulation was investigated with two-way MLR. A dose-dependent reduction in the mean percent incorporation was observed in the range of progesterone concentration between 2 x 10(3) and 10(4) ng/ml with statistically significant differences from the control cultures. Estradiol-17 beta at 10(4) ng/ml produced a slight but significant inhibition of incorporation. No significant change in incorporation occurred with the other steroids tested. Since the suppressive property of progesterone in phytohemagglutinin-induced lymphocyte culture reported in our previous communication was reproduced by the present investigation in MLR, the possible role of progesterone in immunoregulation during pregnancy is emphasized as has been postulated previously.

20-alpha-Dihydroprogesterone↗
PubMed1979

[Contingent negative variation in patients with severe closed head injury--its diagnostic value as a quantitative evaluating method for certain aspect of posttraumatic syndrome (author's transl)].

CNVs were studied in 48 subjects with closed head injury followed by posttraumatic amnesia over than 7 days. Electrical motor-threshold stimulation of the median nerve or subjectively painful stimulation of the fingertip was used for imperative stimulus. An amplitude of CNV and its enhancement by painful imperative stimulus were measured and compared with those obtained from 34 normal subjects. In subacute stage within 3 months after the head injury, correlation between CNV abnormalities and an existence of some noticeable psychiatric disorders was found. In many of the subjects with CNV abnormalities, diffuse slow wave activities were observed in the background EEG, so that it was supposed that CNV abnormalities in subacute stage might reflect diffuse cerebral dysfunction and decreased vigilance. Any statistically significant correlation of CNV abnormalities to an existence of psychiatric disabilities, low score in WAIS and background EEG patterns could not be found in chronic stage 12 months after head injury. However, suppressed CNV was observed in all of 4 subjects who presented generalized epileptic patterns in the background EEG. Many of the subjects with suppressed CNV also showed a small effect of painful imperative stimulus on its amplitude. Statistically significant correlation between CNV abnormalities and work capacity was found. From these findings, together with previous observations (Tsubokawa et al. 19,36,40,44)), it is concluded that the measurement of the CNV is inimitable examination to evaluate certain psychiatric disability which is apt to be overlooked but, in fact, concerned intimately to the work capacity.

Adolescent↗
PubMed1977

[Modulating mechanism of the dorsal column stimulation for pain relief (author's transl)].

The neural mechanism of the modulating effects of spinal cord stimulation upon intractable pain was studied in cats under local anaesthesia. The electrical activity at the centre median nucleus of the thalamus (CEM), which responded to noxious stimuli and was inhibited by nitrous oxide inhalation, was recorded as an indicator of the degree of pain sensation. The suppressed effect upon the evoked potential responding to sciatic stimulation (1 Hz) was recorded during and after train stimulation of various parts of the spinal cord by means of silver ball bipolar electrode. Whenever inhibitory modulating effect upon CEM response was observed by spinal cord stimulation, the bilateral dorsal tractotomy cranial, caudal or both to the stimulating point in order to examine the influence upon the CEM potential. The results are as follows: 1) The CEM evoked potential responding to sciatic stimulation is inhibited by about 30-45% of its amplitude by dorsal column stimulation. This effect corresponds to the inhibitory effect by 75% N2O gas inhalation. Upon dorsal column stimulation, the intraspinal electrical activity is found in the central gray matter the antero-lateral quandrants of the spinal cord as well as the dorsal column. 2) Following lateral or anterior column stimulation as well as dorsal column stimulation, the CEM evoked potential responding to sciatic stimulation is inhibited by about 50% of its amplitude. 3) Following bilateral dorsal tractotomy cranial, caudal or both to the stimulating point, the CEM evoked potentials responding to sciatic stimulation are inhibited by dorsal column stimulation. According to the experimental results, it may be concluded that the inhibitory modulating mechanism by dorsal column stimulation for pain relief is not only mediated through the dorsal column, but also through other ascending spinal pathways.

Animals↗
PubMed1975

Some biological properties of human chorionic follicle stimulating hormone.

The biological properties of human chorionic FSH (hCFSH) for rat ovaries were investigated. Highly purified hCFSH had similar response to the ovarian augmentation test as bovine FSH and significantly enhanced 3H-thymidine uptake by granulosa cells and theca cells in the ovary of hypophysectomized rat. In contrast, highly purified hCG little responded to the ovarian augmentation test and had no effect on 3H-thymidine uptake by the ovary. These results indicate that hCFSH may promote the follicular growth of ovary resulting from granulosa cell proliferation and its enlargement. In addition, freshly harvested porcine granulosa cells were employed in an in vitro system to investigate specific binding of hCFSH to ovarian receptor. Radioiodinated hCFSH (125I-hCFSH) and hCG (125I-hCG) were respectively incubated with cell suspensions. Binding of these hormone preparations was proportional to the cell number and increased with the time of incubation through 120 minutes. The binding ability of 125I-hCFSH to the cells was greater than that of 125I-hCG. Increasing concentrations of unlabeled hCFSH in the incubation mixture progressively inhibited the uptake of 125I-hCFSH by granulosa cells. Unlabeled hCG was not able to compete with 125I-HCFSH binding. The similar phenomenon to inhibit the binding of 125I-hCG to the cells was also recognized in the presence of unlabeled hCG. These findings suggest that granulosa cell has at least two different types of receptor sites: one for hCFSH and the other for hCG.

Animals↗
PubMedDate not supplied

PACS in Kochi Medical School Hospital.

We have evaluated clinically CRT-based diagnosis and the performance of a picture Archiving and Communication System (PACS) in the Department of Radiology, Kochi Medical School. The important requirements of PACS are a good human interface with the diagnostic workstation and a long-term image archiving device. Because the style of image management varies from hospital to hospital, an analysis of the image management policies of each hospital is also important for the configuration of PACS.

Computer Systems↗
PubMedDate not supplied

Brain perfusion in acute encephalitis: relationship to prognosis studied using SPECT.

Single photon emission computed tomography (SPECT) and cranial computed tomography were sequentially examined in 2 patients with acute encephalitis. Radiographic computed tomography revealed focal low-density areas within a few days of the onset of symptoms in both patients. In SPECT, 1 patient exhibited hyperperfusion in the corresponding area, while the other had a normal scan. The outcome of the former was poor, while the latter recovered fully. Abnormal brain perfusion, thus, coincided with a poor prognosis. SPECT may be used to promptly evaluate the focal change of acute encephalitis.

Acute Disease↗