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A Kage

Publications and source records attributed to A Kage.

28 records · Page 2Linked to original sources
PubMed1992

Lectin specificity and binding characteristics of human C-reactive protein.

C-reactive protein (CRP) is thought to play an important role in immunomodulation. The exact biologic function of this pentraxin protein is, however, still unclear. Here we report experiments designed to further characterize the binding properties of CRP. Using purified human CRP it could be shown that CRP immobilized onto polystyrene surfaces or onto latex beads binds distinct plasma glycoproteins including IgG, asialofetuin, asialo-beta 2-glycoprotein I and, likewise, synthetic glycoproteins as a lectin, exhibiting binding specificity for terminal galactosyl residues of the glycoprotein glycans. Binding of CRP to IgA, IgM, IgG, asialofetuin, asialo-beta 2-glycoprotein I and to synthetic glycoproteins requires immobilization onto surfaces of both CRP and the ligand. Fibronectin and fibrinogen are bound by surface-immobilized CRP also in soluble phase. Comparing various mono-, di-, and trisaccharides as competitive inhibitors of the lectin binding activity of CRP, only beta-D-Gal-(1-3)-D-GalNAc, beta-D-Gal-(1-4)-D-GalNAc, and beta-D-Gal-(1-4)-beta-D-Gal-(1-4)-D-GlcNAc had significant inhibitory power at a concentration of 8 mmol/liter. Binding activity of CRP was pH-dependent with an optimum at pH 5 to 6 and was reduced by 90% when pH was shifted from 6 to the physiologic pH value of 7.4. CRP exhibited lectin-like properties with binding specificity for galactosyl residues also when bound to K-562 erythroleukemia cells. It is therefore suggested that CRP immobilized onto surfaces exhibits lectin activity toward galactosyl groups preferentially in a mildly acidic environment as present at sites of inflammation.

Blood Proteins↗
PubMed1986

Automated liquid chromatographic determination of the 20-dihydro isomers of cortisol and cortisone in human urine.

A fully automated method for the simultaneous assessment of cortisol, cortisone and their 20-dihydro isomers in human urine is described. On-line sample enrichment, prepurification, focusing and injection are combined with automated high-performance liquid chromatographic separation and quantification. Losses of steroids throughout the total procedure are negligible. Thus, external calibration is feasible for quantification. Coefficients of variation range between 8.7 and 17.0% for inter-assay variability and between 1.3 and 5.2% for intra-assay variability. Assay sensitivity is 15 nmol/l. In normal students, the medians of the relative excretion rates of free 20 alpha-dihydrocortisol, 20 alpha-dihydrocortisone, 20 beta-dihydrocortisol and 20 beta-dihydrocortisone were 10.9, 6.1, 7.7 and 4.4 mumol/mol creatinine. The fully automated feature renders the present method well suited for routine diagnosis of hypercorticoidism.

Autoanalysis↗
PubMed1985

Determination of urinary free cortisol by "on-line" liquid chromatography.

This is a fully automated method for the specific assessment of urinary free cortisol. A 1-mL urine sample is concentrated and prepurified on a reversed-phase precolumn with alkaline, acid, and organic washes. After selective elution, the cortisol-containing organic eluate is "polarized" by admixing water in such a way that cortisol is focused on the top of a second reversed-phase precolumn. From this precolumn, cortisol is desorbed by backflush, separated from the still-remaining related compounds on an analytical column, and finally detected by ultraviolet absorbance. Losses of cortisol throughout the total procedure are negligible and thus external calibration is feasible for quantification. CVs were 4.1% for interassay variability, 2.6% for intra-assay variability. Cortisol concentrations down to 15 nmol/L are assayable, we estimated the median amount of free cortisol excreted daily by normal students, outpatients, hospitalized patients, and patients under intensive care. After stimulation with corticotropin1-24, the median concentration of free cortisol in urine increased from 99 nmol/L to 1238 nmol/L (n = 6). Results by radioimmunoassay for normal persons and hospitalized patients were about fourfold those by this technique. The same method can also be used for free cortisone in urine.

Autoanalysis↗
PubMed1983

New "on-line" sample-pretreatment procedure for routine liquid-chromatographic assay of low-concentration compounds in body fluids, illustrated by triamcinolone assay.

In this fully automated technique for sample cleanup before chromatographic or other quantitation steps, analytes in body fluids are enriched and semi-purified on a first column. After their selective elution, analytes are "transformed" by admixing appropriate solvents in such a way that they are focused on the top of a second column. By backflush, they then are transferred to an analytical liquid-chromatographic column (or simply eluted for quantification by other techniques). This technique is illustrated by the liquid-chromatographic assay of triamcinolone from a 1-mL urine sample, with ultraviolet detection. Because analytical recovery is almost complete and precision high, no internal standardization is necessary. Interference is eliminated as well as or better than with manual techniques. Chief advantages of this technique are online operation, processing of samples of larger volume, low cost with respect to extraction devices, and nearly universal applicability for exogenous or endogenous compounds of clinical relevance. It potentially may be widely applied.

Body Fluids↗
PubMed1982

Diurnal and ultradian variations of plasma concentrations of eleven adrenal steroid hormones in human males.

The diurnal variations of the plasma concentrations of eleven steroid hormones and of corticotropin (ACTH) were studied in ten young healthy males. The plasma steroids progesterone, pregnenolone, deoxycorticosterone, 17-OH-progesterone, 17-OH-pregnenolone, deoxycortisol, 18-OH-deoxycorticosterone, corticosterone, aldosterone, cortisol and 18-OH-corticosterone, as well as plasma ACTH, were measured at 30-min intervals in the morning and in the evening and at 2-h intervals during the rest of the day. Steroids were extracted from 1 ml plasma, fractionated by high-pressure liquid chromatography (HPLC) and finally quantified by radioimmunoassay (RIA). Plasma concentrations of ACTH were radioimmunoassayed after extraction from 2 ml plasma. More or less pronounced circadian and episodic variations were apparent for plasma levels of all steroids studied, as well as of ACTH. According to related profiles of diurnal variations of plasma concentrations, three different categories of steroids were tentatively crystallized. Category 1 includes 17-OH-pregnenolone, deoxycortisol, corticosterone, 18-OH-deoxycorticosterone, deoxycorticosterone, cortisol and 18-OH-corticosterone, exhibiting a rhythm partly synchronous with that of the pituitary secretory activity of ACTH. Category 2, including progesterone, pregnenolone and 17-OH-progesterone, exhibited a time course of plasma concentrations assuming a regulation predominantly dictated by the testicular secretory activity. Lastly, aldosterone exerted a variation of plasma concentrations which was obviously regulated by the renin-angiotensin system under the present conditions.

Adrenal Cortex Hormones↗
PubMedDate not supplied

Differences in the salivary glycan pattern between children with high and low caries susceptibility.

Interactions between bacterial adhesins of lectin type and the oligosaccharide part of immobilised glycoconjugates on the tooth surface are involved in the specific colonisation of teeth. The specificity of the adhesion process is determined by the carbohydrate specificity of the bacterial lectins and the availability of the corresponding glycosylation pattern. On the other hand the same carbohydrate structures can specifically prevent the binding of bacteria by competitively blocking their adhesion, if sufficient amounts of this distinct carbohydrate structure are available in the secretion. Since carbohydrate binding receptors are also involved in the colonisation of tooth surfaces by cariogenic bacteria, it has been suggested that the architecture of the oligosaccharide portion of soluble glycoconjugates in saliva may play an important role as a constitutional host defence factor in the aetiology of dental caries. Characterising the availability of distinct carbohydrate patterns in saliva by using a pattern of well-described lectins in a competitive lectin inhibition assay we show that in children of a population-based sample a high caries susceptibility is associated with a reduced binding inhibition against the lectin peanut agglutinin (PNA). PNA is specific for the presence of terminal galactosyl residues and binds to the same O-glycan fractions as a surface lectin from Streptococcus mutans. The data suggest that a reduced availability of glycosylation patterns of galactosyl residues detected by the lectin PNA may act as an additional host-derived factor for an increased caries susceptibility.

Acetylgalactosamine↗