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Biomedical subjects

K Shimazaki

Publications and source records attributed to K Shimazaki.

At least 145 records · Page 8Linked to original sources
PubMed1986

Photoaffinity labeling of thaumatin-binding protein in monkey circumvallate papillae.

Thaumatin I is an intensely sweet-tasting protein. It was photo-crosslinked with taste papillae of crab-eating monkey by using a conjugated photo-affinity reagent [3H]azidobenzoylthaumatin I. Serial sections of SDS-polyacrylamide gel electrophoresis of the 0.1 M sodium phosphate buffer-soluble fraction from taste papillae had a large peak of radioactivity at the Mr region of approx. 70,000; fractions from non-taste papillae did not. Excess unlabeled thaumatin I reduced the photo-crosslinking at the 70 kDa region; acetylated thaumatin I (which is not sweet) did not. The results show that taste papillae of the monkey contain a protein of Mr approx. 50,000, which binds to thaumatin I (Mr 22,209) but not to completely acetylated thaumatin I. The possibility that the thaumatin-binding protein is a sweet receptor protein is discussed.

Acetylation↗
PubMed1986

Effect of secretin and caerulein on the absorption of water, electrolytes and glucose from the jejunum of dogs.

The effects of secretin and caerulein on the absorption of water, sodium, potassium and glucose from the jejunum of dogs were investigated. Intravenous infusion of 1 clinical unit (CU; 82 pmol/kg/h) of secretin inhibited jejunal absorption of water, sodium and glucose compared to control period. Adding an intravenous infusion of 0.4 micrograms (300 pmol)/kg/h of caerulein to the infusion of secretin, the jejunal absorption rates of water, sodium and glucose were restored to control values. Intravenous infusions of 0.2 and 0.4 micrograms/kg/h of caerulein induced no significant difference in the absorption compared to control. Thus it seems that secretin inhibits the absorption of water, sodium and glucose from the jejunum of dogs and caerulein, added to secretin, reverses the effect of secretin.

Animals↗
PubMed1985

Comparative study of porous hydroxyapatite and tricalcium phosphate as bone substitute.

This study was performed to quantitate the bone ingrowth and biodegradability of porous calcium phosphate. Two kinds of coralline hydroxyapatite (CHA), along with sintered tricalcium phosphate (TCP), were evaluated. All implants had totally interconnecting pores. These pores measured 260-600 mu for CHA-Goniopora (CHAG), 190-230 microns for CHA-Porites (CHAP), and 100-300 microns for TCP. Cylindrical implants (3 mm in diameter by 8 mm in length) were implanted into the diaphyses of rabbit tibias for 3 to 24 weeks. The quantity of regenerated bone, remaining implant, nonmineralized space, and the middle two quarters of the cortical area were measured by a computerized operator-assisted analysis for bone histomorphometry. At 3 weeks after implantation, 17.3% of CHAG, 11.3% of CHAP, and 7.0% of TCP were infiltrated by regenerated bone. At 24 weeks, 56.1% of CHAG, 52.7% of CHAP, and 44.7% of TCP were occupied by lamellar-type bone. Implant degradation was noted to be 46.4% for TCP and 27.5% for CHAP. In contrast, CHAG did not show appreciable degradation until 24 weeks.

Animals↗
PubMed1985

Cyclic and Noncyclic Photophosphorylation in Isolated Guard Cell Chloroplasts from Vicia faba L.

High rates of both cyclic and noncyclic photophosphorylation were measured in chloroplast lamellae isolated from purified guard cell protoplasts from Vicia faba L. Typical rates of light-dependent incorporation of (32)P into ATP were 100 and 190 micromoles ATP per milligram chlorophyll per hour for noncyclic (water to ferricyanide) and cyclic (phenazine methosulfate) photophosphorylation, respectively. These rates were 50 to 80% of those observed with mesophyll chloroplasts. Noncyclic photophosphorylation in guard cell chloroplasts was completely inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethylurea supporting the notion that photophosphorylation is coupled to linear electron flow from photosystem II to photosystem I. Several lines of evidence indicated that contamination by mesophyll chloroplasts cannot account for the observed photophosphorylation rates.A comparison of the photon fluence dependence of noncyclic photophosphorylation in mesophyll and guard cell chloroplasts showed significant differences between the two preparations, with half saturation at 0.04 and 0.08 millimole per square meter per second, respectively.

Journal Article↗
PubMed1982

Movement disorders of familial neuroacanthocytosis syndrome.

Characteristic movement disorders were observed in two siblings who had neuroacanthocytosis syndrome with normal serum lipoprotein levels. The disorders included orolingual tic-like movements associated with vocalization, biting of the lip and tongue, peculiar dysphagia with bird-like drinking, and postural lapse with abrupt buckling of the knees. In addition, subtle features of parkinsonism and chorea were observed. These movement problems are strikingly similar to those described in cases of neuroacanthocytosis syndrome in several other familial and sporadic cases. Careful observations of these unusual movement disorders may provide a clue to the diagnosis of this rare syndrome.

Acanthocytes↗
PubMed1981

Binding of [35S]saccharin to a protein fraction of rat tongue epithelia.

The binding of [35S]saccharin to ammonium sulfate fractions from homogenates of rat tongue epithelia was measured by equilibrium dialysis. The 40--60% saturated ammonium sulfate fraction from the buffer-soluble fraction had the highest saccharin-binding activity. Binding of [35S]saccharin to the 40--60% ammonium sulfate fraction was inhibited by unlabeled saccharin sodium salt. The inhibition increased with increasing unlabeled saccharin concentration and was nearly complete above 10 mM. [35S]Saccharin binding to the 40--60% ammonium sulfate fraction extracted from the tongue epithelia was inhibited by glucose, lactose and sucrose, while binding to similar fractions from tongue muscle was not affected by these sugars. The inhibition of binding of labeled saccharin to the epithelial fraction increased with increasing glucose concentrations. About 35% of the binding was inhibited by 1 M glucose. No significant difference in the amount of inhibition was seen among the three sugars at 0.1 M. The 40--60% ammonium sulfate fraction from tongue epithelium devoid of taste buds bound much less [35S]saccharin than did a similar fraction from epithelium with taste buds. Binding of [35S]saccharin by the preparation from epithelium devoid of taste buds was not inhibited by glucose. The results provide evidence that the 40--60% ammonium sulfate fraction from tongue epithelia with taste buds contains a protein which binds saccharin and sugars. We hypothesize that it is a sweet taste receptor protein.

Animals↗
PubMed1980

Intramedullary spinal cord metastasis associated with pencil-shaped softening of the spinal cord: case report.

A 57-year-old man presented with a pulmonary mass and subacute onset of paraplegia. Laboratory examination revealed an increased protein content in the cerebrospinal fluid and a normal myelogram. Autopsy disclosed epidermoid carcinoma in the left lower lobe of the lung, intramedullary metastasis at the midthoracic level, and a central pencil-shaped softening above and below the metastatic lesion. The pencil-shaped softening was an ischemic infarct rather than of hemorrhagic or congestive origin. The pathogenesis of this rare association may be explained by the hypothesis of a tumor embolus in the arterial circulation that feeds the center of the cord, producing metastasis. This embolus was followed later by a second embolus to a radicular artery, causing the pencil-shaped softening of the spinal cord.

Carcinoma, Squamous Cell↗
PubMed1979

Spinal cord ischemia and left atrial myxoma.

A 62-year-old man had an acute, transient, flaccid paraplegia. Examination showed a primary cardiac tumor with emboli to major branches of the aorta. A myxoma was removed from the left atrium, and normal function returned. Left atrial myxoma should be suspected as a cause for embolism to the CNS.

Embolism↗
PubMed1978

Studies on electron transfer systems in the marine diatom Phaeodactylum tricornutum. I. Isolation and characterization of cytochromes.

Two cytochromes of the C type, c-550 and c-553, were isolated from the marine diatom, Phaeodactylum tricornutum, and purified by ammonium sulfate fractionation and DEAE-cellulose column chromatography. The cytochrome c-550 had absorption maxima at 550, 522, and 417 nm in the reduced form and at 524, 407, 351, and 277 nm in the oxidized form. It was an autoxidizable acidic protein with an isoelectric point of 5.1 and had a low redox potential of about -0.20 V at pH 7.0. The molecular weight of this cytochrome was close to 17,000. This cytochrome combined with CO and CN-. The CO complex was dissociated reversibly by light. The cytochrome c-553 had absorption maxima at 553, 522.5, and 417 nm in the reduced form and at 528, 410, and 356 nm in the oxidized form. The protein had an acidic isoelectric point of 3.7 and had a high mid-point redox potential of +0.36 V at pH 7.0. Its molecular weight was approximately 10,500. The cytochrome may be considered to be a photosynthetic cytochrome of the f type. Cytochromes of the B type were also found in Phaeodactylum tricornutum; one in soluble form, and the other in bound form. The soluble form had absorption maxima at 560, 529, and 427 nm in the reduced state and at 413 nm in the oxidized state.

Animals↗
PubMed1978

Studies on electron transfer systems in the marine diatom Phaeodactylum tricornutum. II. Identification and determination of quinones, cytochromes, and flavins.

Quinones constituting the electron transfer systems in a marine unicellular diatom, Phaeodactylum tricornutum, were isolated and identified chromatographically. The alga contained five quinones, i.e., plastoquinone A, plastoquinone C, plastoquinone D, alpha-tocopherylquinone, and ubiquinone-9. Other types of quinones, such as vitamin K1, were not detected. The contents of plastoquinone A, plastoquinone C, plastoquinone D, ubiquinone-9, and alpha-tocopherylquinone were 25.5, 4.95, 1.99, 4.78, and 0.28 mmol per mol of chlorophyll, respectively. The contents of the soluble C-type cytochromes, cytochrome c-550 and cytochrome c-553, were 2.15 and 4.34 mmol (heme basis) per mol of chlorophyll, respectively. The amount of B-type cytochrome in the bound form was estimated to be 3.24 mmol (heme basis) per mol of chlorophyll. The acid-soluble flavins, FAD and FMN, were present in amounts of 0.68 and 0.41 mmol per mol of chlorophyll, respectively.

Animals↗