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PubMed1981

Effect of oestradiol valerate on the rat blood--testis and blood--epididymal barriers to [3H]inulin.

Micropuncture samples were taken from rats treated with 2.9 mg oestradiol valerate/day for 14 days, sham injected or untreated. Oestradiol valerate treatment reduced testicular weight and serum testosterone concentrations (P less than 0.05), but did not alter the movement of [3H]inulin into seminiferous tubules or those of the cauda epididymidis. [3H]Inulin concentrations in the seminiferous tubule fluids were always less than 8% of blood isotope concentrations, and those in cauda epididymal tubuule fluid were always less than 5% of blood isotope concentrations. It was concluded that the maintenance of the anatomical component of the blood--testis and blood--epididymal barriers (cell--cell tight junctions) is not androgen-dependent.

Animals↗
PubMed2005

Measurement of glomerular filtration rate via urinary clearance of inulin and plasma clearance of technetium Tc 99m pentetate and exogenous creatinine in dogs.

OBJECTIVE: To compare glomerular filtration rate (GFR) measured via urinary clearance of inulin (UCI) with plasma clearance of technetium Tc 99m pentetate (99mTc-pentetate) and creatinine in dogs. ANIMALS: 6 healthy Beagles and 18 Beagles with reduced renal function. PROCEDURE: 13 blood samples were obtained between 5 and 600 minutes after i.v. bolus injections of (99m)Tc-pentetate and creatinine. Plasma clearance of (99m)Tc-pentetate was computed on the basis of 1, 2, or 13 samples, and plasma clearance of creatinine was computed on the basis of 2, 5, or 13 samples. During plasma clearance procedures, constant i.v. infusion of carboxyl carbon 14 inulin was begun and UCI was determined in urine collected from 90 to 120, 120 to 180, and 180 to 240 minutes. Clearance procedures were repeated in 12 dogs to evaluate reproducibility of results. RESULTS: Significant association between UCI and plasma clearance was determined via all methods. However, plasma clearances were moderately to markedly different from UCI, depending on test substance, GFR, and sample numbers used for plasma clearance computations. Comparisons were particularly discordant when some methods of limiting samples were used to define plasma clearance. CONCLUSIONS AND CLINICAL RELEVANCE: Values derived from plasma clearance methods for (99m)Tc-pentetate and creatinine were not interchangeable with UCI results, which raises questions about their reliability as clinical research tools for measurement of GFR. Plasma clearance methods that are relative indices of renal function should not be interpreted as accurate measures of GFR without validation.

Analysis of Variance↗
PubMed1976

Comparison of inulin, iothalamate, and 99mTc-DTPA for measurement of glomerular filtration rate.

Clearances of inulin, 125I-iothalamate, and 99mTc-Sn-DTPA were measured simultaneously in five mongrel dogs exhibiting a wide range of glomerular filtration rates (GFR). Standard constant-infusion inulin clearance was compared to radionuclide clearances after subcutaneous injection of the emitters mixed with aqueous epinephrine. All three substances were found to have virtually identical clearances. The accuracy, accessibility, low cost, low radiation hazard, and short half-life of 99mTc-Sn-DTPA make it an excellent substance for measuring GFR. The subcutaneous technique offers an accuracy comparable to the more difficult constant-infusion method.

Animals↗
PubMedDate not supplied

Pharmacokinetics of inulin in blood and central lymph in the rat.

Inulin was used as a model drug for the study of factors influencing the transport of drugs across the blood-lymph barrier. The model drug was administered iv (0.75, 7.5 and 37.5 mg/kg) as a bolus and by infusion. Kinetic parameters in blood and central lymph including lymphatic bioavailability (FL) were determined. It has been found that FL is influenced (increased) by larger doses of inulin (FL extent 0.934 +/- 0.250 - 1.914 +/- 0.250), infusion concentration ratio lymph/blood in steady state was 0.941 +/- 0.013. Identical kinetic parameters were found in rats with differentiated content of total lipids in lymph (in fed and fasted group, FL were 0.861 +/- 0.167 and 0.934 +/- 0.250 respectively).

Animals↗
PubMed1990

[Comparative studies of the clearance of inulin and creatinine in swine].

Endogenous creatinine clearance was determined in 5 healthy female pigs of different body weight simultaneously to the clearance of inulin. The average creatinine clearance (3.74 +/- 0.57 mg/min/kg) has been found to be 7% higher than inulin clearance indicating some tubular secretion of creatinine. However, since this difference was not significant, the endogenous creatinine clearance is a practicable method for the measurement of glomerular filtration rate in swine. Data of creatinine concentration in plasma and of creatinine excretion showed close relationships to the body weight. It is discussed, whether the glomerular filtration rate can be predicted from the creatinine concentration in plasma and creatinine excretion, which might be estimated from the body weight without quantitative urine collection.

Animals↗
PubMed1989

Assessment of renal function by inulin clearance: comparison with creatinine clearance as determined by enzymatic methods.

We compared creatinine clearances determined by enzymatic (Kodak Ektachem 700 single-slide, Boehringer Mannheim creatinine PAP) and nonenzymatic (Jaffé, HPLC) methods with glomerular filtration rate measured by inulin clearance in patients with varying degrees of renal function. The Kodak enzymatic assay gave values for creatinine 2 to 3 mg/L higher than the other methods. This resulted in significantly lower creatinine clearances than inulin clearances and creatinine clearances determined by the other methods. However, correlations between all methods for serum and urinary creatinine values and clearances were good. To avoid between assay (enzymatic vs nonenzymatic) discrepancies, manufacturers should agree to an acceptable standard of calibration under the usual conditions used with patients.

Chromatography, High Pressure Liquid↗
PubMed1988

[Comparison of inulin and creatinine clearance determinations in anesthesized and conscious rats].

Two investigation methods of the renal function by means of the inulin and the endogenous creatinine clearance in narcotized and conscious rats are described in detail. The inulin clearance was 0.84 +/- 0.16 ml/min/100 g BW. The results of the creatinine clearance obtained by 6 various methods are widely different due to co-determination of foreign chromogens. Therefore, it is important to compare these results with the results of other analytical methods determining only the "true" creatinine.

Anesthesia, General↗
PubMed1987

Theophylline distribution kinetics analyzed by reference to simultaneously injected urea and inulin.

Theophylline distribution kinetics were studied after i.v. injection in five anesthetized dogs. [14C]Urea and inulin were injected simultaneously as reference compounds to measure body fluid spaces and to calculate compartmental blood flows and permeability coefficient-surface area products for transcapillary exchange. The distribution of all three compounds was modeled with three-compartment systems in which the central compartment corresponds to intravascular space. The total volume of theophylline distribution averaged 0.72 +/- 0.09 liters/kg (+/- S.D.), indicating net tissue binding as reflected in a tissue/intracellular water partition coefficient of 1.17 +/- 0.10. Cardiac output measurements averaged 4.78 +/- 0.95 liters/min and were similar to the sum of compartmental blood flows estimated from the intercompartmental clearances of urea and inulin (4.62 +/- 1.10 liters/min) and to the sum of theophylline intercompartmental clearances (5.10 +/- 1.29 liters/min). Theophylline intercompartmental clearance to each peripheral compartment was faster than expected from its free-water diffusion coefficient and was similar to estimated compartmental blood flow. It is possible that theophylline transcapillary exchange is carrier mediated and that its rapidity contributes to the frequency of adverse reactions after i.v. administration of this drug.

Animals↗
PubMed1986

Membrane pores in hypotonically dialyzed sheep erythrocytes remain open after three weeks of storage: entrapment of different stokes radius probes, [14C]sucrose and [3H]inulin.

Sheep carrier erythrocytes were prepared from dialyzed cells stored for 3 weeks. The initial pore size in freshly dialyzed cells exceeds the Stokes radius of that for hemoglobin. Hypotonically dialyzed erythrocytes are then very stable in a porous state. Two probes of different Stokes radius were used to determine the relative size of the pores. Sheep erythrocytes entrap inulin to a greater extent than sucrose, a much smaller molecule. With storage, a greater fraction of dialyzed cells become impermeable to inulin than to sucrose indicative of pore size greater than 5.2 less than 20 A. Since hemoglobin content did not change relative to storage, the pore size was less than the Stokes radius of hemoglobin. Pores generated by controlled hypotonic dialysis are unlike the single rupture pore found in erythrocyte ghosts.

Animals↗
PubMedDate not supplied

Intramuscular absorption and regional lymphatic uptake of liposome-entrapped inulin.

An investigation of the effects of the liposome variables (size, surface area, and amount of injected lipid) on the intramuscular absorption and subsequent lymphatic uptake of drug from the injection site (left muscle) and in the opposite (right) muscle and lymph node was done in mice. Two size ranges were studied (0.3-2.0 mu and 0.15-0.7 mu). Large multilamellar vesicles were studied at lipid doses of 20.7 and 9.0 mg/kg, whereas small multilamellar vesicles were investigated at a dose of 9.5 mg/kg. Liposomes were composed of phosphatidylcholine/cholesterol/phosphatidylserine/alpha-tocopherol/14C-dipalmitoylphosphatidylcholine (as a marker for the lipid phase), 4:5:1:0.01:0.01 (molar ratio). 3H-inulin was used to monitor the aqueous phase. At 24 hr after administration, large liposomes tended to result in the largest fraction of drug at the injection site, with the 3H/14C ratio indicating stability of the remaining vesicles. Small liposomes showed a greater uptake of inulin via the lymphatics. Decreasing the total amount of injected lipid resulted in a slower absorption of large liposomes and a greater uptake via the lymphatics.

Absorption↗
PubMed1977

Photometry of inulin and polyfructosan by use of a cysteine/tryptophan reaction.

Described are a macromethod for measuring 2 to 30 mug of polyfructoside in sample volumes of 0.5 ml and a micromethod for measuring 40 to 400 ng in 10-mul samples. The absorptivity of the cysteine/tryptophan color product is 2.5-to 10-fold those found with use of five other colorimetric methods for inulin. The method is highly specific for alkali-stable polyfructoside. Color, measured at 515 nm, was maximal on development at 56 degrees C for 25 min in dilute (57-58% by vol) sulfuric acid, after the addition of the combined cysteine hydrochloride/tryptophan reagent. Analytical recoveries of inulin and polyfructosan from plasma and urine were complete. With initial alkaline heating, the endogenous blank inulinoid values averaged 0.6 +/- 0.47 (SD) mg/liter for plasma and 0.05 +1- 0.024 mg/min for urine. The coefficient of variation of the macromethod was less then 3%; that for the micromethod ranged from 1.3 to 6.3%. The micromethod appears adaptable to the determination of nanogram quantities of polyfructoside in nanoliter volumes of biological fluids.

Adult↗
PubMed2004

The cytoprotective effect of inulin-type hexasaccharide extracted from Morinda officinalis on PC12 cells against the lesion induced by corticosterone.

High concentration of corticosterone (Cort) 0.2 mM was incubated with PC12 cells to simulate the lesion state of brain neurons in depressive illness, it was found that the inulin-type oligosaccharides extracted from Morinda officinalis, inulin-type hexasaccharide (IHS) at the doses of 0.625, 1.25 microM or desipramine (DIM) 0.25, 1 microM protected the PC12 cells from the lesion induced by Cort. With Fura-2/AM labeling assay, DIM 0.25, 1 microM or IHS 2.5, 10 microM attenuated the intracellular Ca2+ overloading induced by Cort 0.1 mM for 48 h in PC12 cells. Using RT-PCR, treatment with Cort 0.1 mM for 48 h decreased the nerve growth factor (NGF) mRNA level in PC12 cells, IHS 5, 10 microM reversed this change. In summary, IHS attenuate the intracellular Ca2+ overloading and thereby up-regulate the NGF mRNA expression in Cort-treated PC12 cells, which may be consisted at least part of the cytopretective effect of IHS. These results also extend evidence for our hypothesis that neuroprotective action is one of the common mechanisms for antidepressants.

Analysis of Variance↗
PubMed2001

Cresol red thallium acetate sucrose inulin (CTSI) agar for the selective recovery of Carnobacterium spp.

Carnobacterium spp. are commonly isolated from a variety of foods, especially from meats stored under anaerobic atmospheres at refrigeration temperatures, but the role of these organisms in the spoilage of meat and meat products is yet to be determined. Cresol Red Thallium Acetate Sucrose (CTAS) agar was developed as a selective medium for enumeration of carnobacteria, however problems such as poor recovery of Carnobacterium spp. and interference by other microorganisms have precluded its general use. The aim of this study was to improve CTAS agar by broadening its spectrum of selective recovery for carnobacteria while restricting the ability of interfering species to grow. Ten Carnobacterium spp. (five ATCC cultures and five isolates from fresh pork) and 20 other genera were used in testing the agar. A wider range of Carnobacterium spp. recovery was obtained by modifying concentrations of sucrose, manganese sulphate and thallium acetate. Additions of inulin and thiamine hydrochloride also improved growth response. The additions of vancomycin and Chrisin (nisin) eliminated interference from other microorganisms. A two-temperature incubation procedure was included to improve the characteristic growth of Carnobacterium spp. on the modified medium, identified as Cresol Red Thallium Sucrose Inulin (CTSI) agar. Lactic acid bacteria and Enterobacteriaceae were unable to grow on CTSI incubated aerobically. Growth of Carnobacterium spp. on CTSI yielded pink colonies, except for Cb. mobile, which formed gray colonies. In some instances, a red precipitate formed in the center of the colony. Yellowing and clearing of the growth medium was also frequently observed. Recovery of carnobacteria using CTSI was identical to that obtained with All Purpose Tween (APT) agar.

Agar↗
PubMed2001

Simultaneous determination of inulin and p-aminohippuric acid in plasma and urine by reversed-phase high-performance liquid chromatography.

A simple, accurate and sensitive high-performance liquid chromatographic method with UV detection was carried out to measure simultaneously plasma and urine concentrations of both p-aminohippuric acid and inulin. Following a simplified acid hydrolysis of the sample, the separation was carried out in 4 min using a C18 reversed-phase column with a flow-rate of 1 ml/min, and monitoring the absorbance at 280 nm. Within the investigated concentration ranges of inulin (0.1-3.2 mg/ml) and p-aminohippuric acid (0.0097-0.3 mg/ml), good linearity (r>0.99) was obtained. Within-run RSD ranged from 2.9 to 6.1% and between-run RSD ranged from 6.4 to 10%. Analytical recoveries were 101-112%, with little differences between plasma and urine samples. The detection limit was 1 microg/ml for all the analytes studied. This method might be ideal for renal function studies where a rapid and reproducible assessment of both renal glomerular filtration rate and blood flow-rate is required.

Adult↗
PubMed2006

Structural and functional insights into intramolecular fructosyl transfer by inulin fructotransferase.

Inulin fructotransferase (IFTase), a member of glycoside hydrolase family 91, catalyzes depolymerization of beta-2,1-fructans inulin by successively removing the terminal difructosaccharide units as cyclic anhydrides via intramolecular fructosyl transfer. The crystal structures of IFTase and its substrate-bound complex reveal that IFTase is a trimeric enzyme, and each monomer folds into a right-handed parallel beta-helix. Despite variation in the number and conformation of its beta-strands, the IFTase beta-helix has a structure that is largely reminiscent of other beta-helix structures but is unprecedented in that trimerization is a prerequisite for catalytic activity, and the active site is located at the monomer-monomer interface. Results from crystallographic studies and site-directed mutagenesis provide a structural basis for the exolytic-type activity of IFTase and a functional resemblance to inverting-type glycosyltransferases.

Amino Acid Sequence↗
PubMed1997

Molecular cloning of an inulin fructotransferase (depolymerizing) gene from Arthrobacter sp. H65-7 and its expression in Escherichia coli.

The gene encoding an extracellular inulin fructotransferase (depolymerizing) (inulase II) (EC 2.4.1.93), designated ift gene, was cloned from the genomic DNA of Arthrobacter sp. H65-7, and expressed in Escherichia coli for the first time. Sequence analysis showed a single open reading frame consisting of 1314 base pairs that encoded a signal peptide of 32 amino acids and a mature protein of 405 amino acids. The primary structure showed a homology of 49.8% with that of the inulin fructotransferase (DFA I-producing) (EC 2.4.1.200) from Arthrobacter globiformis S14-3. E. coli cells carrying the ift gene produced the active enzyme under control of the lac promoter. The expression of the ift gene was improved by a plasmid, pIFT-B, in which the ift gene was immediately downstream from the lac promoter. An E. coli transformant carrying pIFT-B expressed twice as much activity of inulase II as that of the original strain, Arthrobacter sp. H65-7. Most of the enzyme activity existed within the cells.

Amino Acid Sequence↗
PubMed1991

[Activation of human serum complement with inulin and purification of SC5b-9].

During a study of the effect of inulin on human complement, we found that complements were partially activated after incubation with inulin for one hour and completely activated after incubation for three hours at 37 degrees C. SC5b-9 was purified by DEAE-Sephacel chromatography, linear sucrose density gradients centrifugation and anti-IgM-protein A affinity chromatography. Purified SC5b-9, as assayed by immunoelectrophoresis, was a single fraction and had C5b, C6, C7/C8 alpha gamma, C8 beta, C9, C92, and S-protein bands appearing in the 10% SDS-PAGE.

Complement Activation↗