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Biomedical subjects

K Fukui

Publications and source records attributed to K Fukui.

At least 451 records · Page 25Linked to original sources
PubMed1982

Purification and properties of glucosyltransferase responsible for water-insoluble glucan synthesis from Streptococcus mutans.

A glucosyltransferase responsible for water-insoluble glucan synthesis was purified from the culture fluids of Streptococcus mutans 6715-15 strain by column chromatography on Toyopearl HW-60 and subsequently on hydroxyapatite. The enzyme preparation gave a single band on analysis by polyacrylamide gel electrophoresis. The pH dependency of the activity showed two optimal peaks at 5.8 and 7.3 and the Km values for sucrose were 1.4 and 3.3 mM at the respective optimal pHs. The molecular weight determined by sodium dodecyl sulfate gel electrophoresis was 180,000. Although the enzyme scarcely synthesized water-insoluble and water-soluble glucans from sucrose, water-insoluble glucan formed from sucrose in the presence of dextran T10 consisted of over 93% alpha-1, 3-glucosidic linkage. Analysis of the structure of water-insoluble glucan indicated that the enzyme catalyzed the formation of branch points in alpha-1,6-glucan (dextran) and transferred the glucosyl moiety of sucrose to the C-3 position of the branching glucose residue of dextran. Since this enzyme has not yet been registered, we named it mutansynthetase (EC 2.4.1.?).

Chemical Phenomena↗
PubMed1981

Correlative ontogenetic development of catecholamine- and LHRH-containing nerve endings in the median eminence of the rat.

The ontogenetic development of catecholamine (CA)- and LHRH-containing nerve endings in the median eminence of the rat was investigated by combining fluorescence histochemistry and immunohistochemistry in the same tissue section. LHRH-terminals appeared earlier than CA-terminals and were already detectable in the lateral part of the external layer of the central ME on the first day after birth. CA-nerve endings were first seen in a corresponding region of the ME on the seventh postnatal day. At this stage both types of terminals showed the earliest manifestation of a correlative pattern of their distribution. Subsequently the development of both types of nerve endings proceeded rapidly, and at 14 days their distribution pattern corresponded to that in adult animals. The authors conclude that at this stage the CA-neurons play a constant and significant role in the release of LHRH into the portal capillaries. The correlation between both types of nerve endings and the ontogenetic development of the capillary plexuses of the hypophysial portal system is discussed.

Age Factors↗
PubMed1980

Location of Streptococcus mutans in the dentinal tubules of open infected root canals.

Seventy-six teeth from open canals were extracted to prepare serial longitudinal sections. The sections were made from apical portions of the teeth and stained. Ninety similar teeth were extracted to prepare dentinal splinters with files from the enlarged infected canal. The splinters were spread on a selected medium to grow S. mutans. S. mutans was detected in 48.7% of the 76 teeth examined. The distance of invasion of S. mutans in the dentinal tubules revealed by immunofluorescence averaged 509 micrometer from the canal wall and reached 1150 micrometer, depending on the serogroups of S. mutans. Unidentified germs in the sections which were demonstrated by Gram's stain invaded further than S. mutans. The frequency of appearance of the serogroups of S. mutans was 32.6% (d), 27.9% (c), 24.4% (a), and 15.5% (b).

Adolescent↗
PubMed1979

Pain and the bulbospinal noradrenergic system: pain-induced increase in normetanephrine content in the spinal cord and its modification by morphine.

Experiments were carried out to determine whether noxious stimulation produced biochemical changes in noradrenergic neurons in the spinal cord of rats and whether morphine induced different biochemical effects in the presence and the absence of noxious stimuli. Noxious stimuli, but not stress, significantly increased the normetanephrine (NM) concentration only in the dorsal half of the spinal cord without affecting the noradrenaline concentration. The NM increase induced by noxious stimuli remained after transection at the inter-collicular level. The NM increase induced by noxious stimuli remained after transection at the inter-collicular level. When the noxious stimulation was blocked by lidocaine at the peripheral level, the NM increase disappeared. THe NM concentration elevated by pain, was further increased by morphine. The data suggest that the bulbospinal noradrenergic system works as a pain control system: pain itself slightly activates this system, but not to the extent of producing analgesia and the addition of morphine further activates this system to a level sufficient to produce analgesia.

Animals↗
PubMed1979

Clinical evaluation of thyroid CT values in various thyroid conditions.

CT scans of the thyroid were performed with a Hitachi CT-W2 device. The CT value of the region of interest (ROI) was obtained from CT images of the thyroid. Mean and standard deviation was 112 +/- 10 in 44 normals. Out of 27 cases of hyperthyroidism, the CT value of 13 untreated cases of 58 +/- 4, and that of 13 cases under treatment was 73 +/- 7 in average. The CT value of the single cured case was 100. Twelve cases of chronic thyroiditis and 5 cases of hypothyroidism showed averages of 57 +/- 11 and 36 +/- 13, respectively. The results of the above-mentioned clinical study indicate the estimation of the CT value of the thyroid is useful for diagnosis of various thyroid conditions.

Humans↗