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Biomedical subjects

T Kuwana

Publications and source records attributed to T Kuwana.

At least 55 records · Page 3Linked to original sources
PubMed1993

Bone-derived serum enzymes and bone density in perimenopausal Caucasian women.

Serum levels of bone-origin alkaline phosphatase and of tartrate-resistant acid phosphatase were measured in Caucasian women aged 41-69 years who had volunteered for bone densitometry. Bone alkaline phosphatase and tartrate-resistant acid phosphatase were inversely correlated with vertebral bone density and with femoral neck bone density. Bone alkaline phosphatase and acid phosphatase were also significantly correlated, consistent with the concept of 'coupling' between osteoblast and osteoclast activity.

Acid Phosphatase↗
PubMed1992

Early diagnosis of acute myocardial infarction by CK-MB mass measurements.

We have studied the changes in creatine kinase (CK) and creatine kinase MB (CK-MB) activity and concentration for the diagnosis of acute myocardial infarction in 73 patients admitted to the coronary care unit with cardiac symptoms of 12 h duration or less. Serial blood samples were obtained for an 8 h period following admission and CK, CK-MB activity and concentration measured. We compared the performance of single values at optimized diagnostic cut-offs and incremental change (log slope) for all three measurements. CK slope combined with CK-MB concentration measurements allowed accurate diagnosis at 4 h from admission. CK-MB concentration determination 8 h from admission (12-16 h from the onset of chest pain) was the most efficient single measurement. Rapid diagnostic categorization and possible selection of patients for thrombolysis in patients with an uncertain admission diagnosis is possible by these techniques.

Adult↗
PubMed1992

A method to obtain avian germ-line chimaeras using isolated primordial germ cells.

Primordial germ cells (PGCs), collected from the blood of 2-day-old chick embryos, were concentrated by Ficoll density centrifugation. The blood contained 0.048% PGCs and the concentrated fraction contained 3.9% PGCs in blood cells. The PGCs were picked up with a fine glass pipette, and one hundred were then injected into the terminal sinuses of 2-day-old Japanese quail embryos (24 somites); bubbles were then inserted to prevent haemorrhage. The embryos were further incubated at 38 degrees C for 24 h, and then fixed. Serial sections were stained with the periodic acid-Schiff reagent (PAS) to demonstrate chicken PGCs and with Feulgen stain to identify quail cells. On the basis of the differences in staining properties, 63.6 +/- 5.3 chick PGCs were detected in the quail embryo in the area where the gonads develop. Furthermore, 39.3 +/- 4.5 chick PGCs were incorporated into the quail germinal epithelium within 24 h of the injection. A similar percentage of the host (quail) PGCs had also migrated to the germinal epithelium at the same stage of development. This technique for obtaining germ-line chimaeras will facilitate research on avian germ-line differentiation.

Animals↗
PubMed1991

Ion channel sensors for glutamic acid.

Coulometric biosensors using glutamate receptor (GluR) ion channel protein as a signal-amplifying sensory element that exploit the glutamate-triggered Na+ ion current through bilayer lipid membranes have been fabricated. The formation of stable planar bilayer lipid membranes was achieved by applying the folding method across a small circular aperture bored through a thin polyimide film. The multichannel type sensing membranes, formed across an aperture of ca. 120 microns diameter, contained more than 10 GluR proteins and showed L-glutamate-triggered response as a composite of individual single-channel currents. The single-channel type sensing membranes, formed across an aperture of ca. 20 microns diameter, contained a sufficiently small number of GluR proteins so that the response was observed as a series of single-channel pulse currents. Dependence of the integrated channel current on the glutamate concentration was examined. A sharp concentration dependence of up to ca. 1.5 x 10(-7) M and 3 x 10(-6) M for the multichannel and single-channel type sensors, respectively, was observed. A high selectivity for L-glutamate compared with D-glutamate for inducing the channel current was observed. A detection limit as low as ca. 3 x 10(-8) M was attained for the multichannel type sensor. This remarkable sensitivity is discussed in terms of the potential use of GluR ion channel protein for a new type of sensing system.

Biosensing Techniques↗
PubMed1991

Ectopic colonization of primordial germ cells in the chick embryo lacking the gonads.

Chick primordial germ cells (PGCs) first appear in the extraembryonic region in the early embryo, then temporarily circulate via the blood vascular system and finally migrate into the gonadal anlagen. In the present study, we examined the trend of ectopic distribution of PGCs in the chick embryo when its future gonadal region had been removed at an early stage. Embryos at stage 10, from which the caudal third region was excised, were incubated until they reached stages 14 to 20. In embryos at stage 14, about 80% of the total PGCs were found in the capillaries of the yolk sac, whereas others were observed in the head, mainly in the mesenchyme and small vessels close to the neural tube. From stage 18 onward, many PGCs accumulated in the embryo proper; about 90% of them colonized in the head region around the neural tube. These ectopic PGCs in the head were found in the capillaries, sometimes as thrombi or emerging from them into the adjacent mesenchyme. These results show that, when the chick embryo lacked gonads, the PGCs could be concentrated in the head region and migrated from the capillaries into the mesenchyme.

Animals↗
PubMed1991

Intestinal origin alkaline phosphatase activity in plasma for differential diagnosis of jaundice.

Intestinal origin alkaline phosphatase activity (ALP) in plasma was measured by a sensitive immunocapture assay in 104 jaundiced patients--84 with intrahepatic and 20 with post-hepatic jaundice. Increased enzyme activities were observed in those with intrahepatic disease and subnormal values in those with post-hepatic disease. At a discriminant level intestinal origin ALP showed a diagnostic sensitivity of 77% for intrahepatic cholestasis, with a diagnostic accuracy of 75% for its differentiation from post-hepatic jaundice. This diagnostic accuracy is not as good as that derived with other techniques--for example, imaging--and the technique is therefore not recommended as a supplement or replacement.

Alkaline Phosphatase↗
PubMed1991

Measurement of alkaline phosphatase of intestinal origin in plasma by p-bromotetramisole inhibition.

L-p-bromotetramisole was used to inhibit non-intestinal alkaline phosphatase (of liver or bone origin) (EC 3.1.3.1; ALP) in plasma, and intestinal ALP was measured from the uninhibited activity. The method of determination is convenient and correlated well with measurement by immunocapture assay. If carried out in parallel with wheat-germ lectin precipitation of bone ALP, subtraction of intestinal ALP activity from that of non-bone ALP in the supernatant can be used to measure the ALP that originates from the liver in men and non-pregnant women.

Alkaline Phosphatase↗
PubMed1991

Sugar chain heterogeneity of bone and liver alkaline phosphatase in serum.

Fractionation of bone and liver alkaline phosphatase (EC 3.1.3.1; ALP) in serum by serial lectin affinity chromatography has demonstrated differences in the sugar chain structure of bone and liver ALP in serum from that previously reported in the corresponding tissues, with a lower content of high mannose or hybrid-type sugar chains and a higher content of biantennary complex-type chains. Furthermore, the bone and liver ALPs were found to differ in the latter with the bone fraction showing a greater content of fucose residues.

Adult↗
PubMed1990

Oxalate/hydrogen peroxide chemiluminescence reaction. A 19F NMR probe of the reaction mechanism.

The mechanism of the oxalate/hydrogen peroxide chemiluminescence reaction has been examined by magnetic resonance techniques. Investigation of the reactive intermediates involved in chemiluminescence was carried out with bis(2,6-difluorophenyl)oxalate (DFPO) using 19F NMR to probe its reactions with aqueous hydrogen peroxide. Formation and reactions of the intermediate hydroperoxy oxalate ester B along with the formation of the half ester product C and difluorophenol D were monitored by 19F NMR. When the reaction of DFPO and aqueous hydrogen peroxide was carried out in the presence of dansylphenylalanine, a typical fluorescent analyte, the intensity of the resonance due to the intermediate B was diminished in direct proportion to the concentration of the analyte. Comparison of the time/intensity profile of the chemiluminescence emission with that of the 19F NMR transient suggests that the hydroperoxy oxalate ester B is the likely 'reactive' intermediate, capable of participating in a chemically initiated electron exchange luminescence mechanism.

Fluorine↗
PubMed1990

Intestinal variant alkaline phosphatase in plasma in disease.

We investigated by enzyme electrophoresis after prolonged neuraminidase treatment the activity of "intestinal variant" (alpha 2-globulin mobility) alkaline phosphatase (EC 3.1.3.1; ALP) in the plasma of 189 patients selected for disorders (diabetes mellitus, liver cirrhosis, and chronic renal failure) with a known high frequency of increased plasma intestinal (beta-globulin mobility) ALP activity. The overall frequency of the variant ALP was 23.8%, whereas in the samples showing intestinal ALP it was 45.0%. The variant ALP was not observed in the absence of intestinal ALP, nor in patients of blood group A. Its frequency did not differ significantly between the different patient groups. Quantification of the variant ALP by densitometry was unsatisfactory but the quantity could be estimated by subtracting the intestinal ALP activity measured by electrophoresis from the activity determined by immunoassay with monoclonal antibody that reacts with both the intestinal and the variant forms. This indicated median activity of 12 U/L for the variant, approximately equal to that of the concomitant intestinal ALP. From the effects of papain and bromelain treatments, we suggest that "intestinal variant" represents intestinal ALP with attached membrane-binding domain.

Alkaline Phosphatase↗
PubMed1989

Determination of desmosine, isodesmosine, and other amino acids by liquid chromatography with electrochemical detection following precolumn derivatization with naphthalenedialdehyde/cyanide.

Naphthalenedialdehyde (NDA) in the presence of cyanide (CN) reacts with primary amines to produce fluorescent cyano[f]benzoisoindole (CBI) derivatives. These derivatives have been shown to be substantially more stable than the corresponding o-phthalaldehyde derivatives. However, one drawback of this method is that compounds derivatized at more than one site exhibit quenching, precluding the use of fluorescence detection. The CBI derivatives have been found to be electroactive and are oxidized at a modest oxidation potential (+750 mV). Electrochemical detection is especially useful for the analysis of compounds containing more than one primary amine site because the response is not attenuated as it is in fluorescence detection. Desmosine and isodesmosine were of particular interest because of their importance in elastic fiber and the lack of highly sensitive HPLC methods for the determination of these compounds. Both of these compounds react with NDA/CN to produce electrochemically active derivatives. The combination of derivatization with NDA/CN and electrochemical detection was found to be linear over three orders of magnitude. Detection limits for CBI-lysine and CBI-desmosine were 100 fmol at a S/N of 2. Amino acids in elastin were quantitated using this method. The results correlate well with what has been reported previously in the literature. A significant advantage of the use of liquid chromatography with electrochemical detection with precolumn derivatization with NDA/CN for the analysis of desmosine and isodesmosine is that they can be separated and quantitated individually using this method. In addition, the unique voltammetry of multiderivatized CBI-amino acids can be used to verify peak purity.

Aldehydes↗