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PubMed1988

Stool caproic acid for screening of Clostridium difficile.

Clostridium difficile is the prime etiologic agent in the production of pseudomembranous colitis by its powerful cytotoxin. The most common test for the toxin is a tissue culture method with neutralization of cytopathic effect by a C. difficile antiserum. This method is expensive and requires a minimum of 72 hours before results can be obtained. Attempts to create a rapid method, counterimmunoelectrophoresis, enzyme-linked immunosorbent, latex agglutination, and fluorescent antibody test are fraught with many problems. This report describes a rapid method for the identification of C. difficile, using gas-liquid chromatography (GLC) for the demonstration of caproic acid, a product of the organisms fatty acid metabolism.

Bacterial Proteins↗
PubMed2001

Chemopreventive effects of ONO-8711, a selective prostaglandin E receptor EP(1) antagonist, on breast cancer development.

Levels of prostaglandin E(2) (PGE(2)) in human and rodent breast cancers are higher than surrounding normal tissues. PGE(2) exhibits biological activity through binding to membrane receptors, EP(1-4). The present study was designed to investigate the effects of ONO-8711, a newly synthesized selective PGE receptor EP(1) antagonist, on 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-induced breast cancer development. Starting at 7 weeks of age, female Sprague-Dawley (SD) rats were given PhIP (85 mg/kg body weight) by gavage four times weekly for two weeks. Dietary administration of ONO-8711 at 400 or 800 p.p.m. delayed occurrence of breast tumors for 2 or 4 weeks, respectively. At 20 weeks after the last dosing of PhIP, all animals were killed and complete autopsy was made. All breast tumors were diagnosed as invasive ductal adenocarcinomas histopathologically. Administration of ONO-8711 at 800 p.p.m. significantly decreased PhIP-induced breast cancer incidence, multiplicity and volume compared with those of rats fed the control diet (56% versus 79%, P < 0.05, 1.2 versus 2.5, P < 0.05, 0.7 versus 1.4 cm(3), P < 0.01, respectively). Apoptosis was significantly increased in breast cancer cells by feeding of ONO-8711 at 800 p.p.m. of 158% (P < 0.05). EP(1) receptor was detected by reverse transcription-polymerase chain reaction (RT-PCR) in breast cancers, not in normal tissues. These results suggest that EP(1) receptor is associated with breast cancer development and selective PGE receptor EP(1) antagonists may possess chemopreventive effects through the induction of apoptosis without any side effects.

Animals↗
PubMed2006

A prostaglandin E2 receptor subtype EP1-selective antagonist, ONO-8711, suppresses 4-nitroquinoline 1-oxide-induced rat tongue carcinogenesis.

We previously reported that certain cyclooxygenase (COX) inhibitors could inhibit chemically induced tongue carcinogenesis. In the present study, we investigated the effects of prostaglandin E(2) (PGE(2)) receptor EP(1)-selective antagonist ONO-8711 on 4-nitroquinoline 1-oxide (4-NQO)-induced oral carcinogenesis to know whether an EP(1) receptor involves in oral carcinogenesis. Male Fischer 344 rats were given drinking water containing 4-NQO for 8 weeks (20 p.p.m. for the initial 2 weeks, 25 p.p.m. for 2 weeks, and then 30 p.p.m. for 4 weeks). After 4-NQO treatment, animals were given 400 or 800 p.p.m. ONO-8711 containing diets for 23 weeks. The incidence of tongue squamous cell carcinomas (SCC) in the 4-NQO-treated rats was 64%, while that in the rats given ONO-8711 after 4-NQO exposure was 29 (P<0.05) and 29% (P<0.05) in the 400 and 800 p.p.m. of ONO-8711, respectively. The multiplicity of tongue cancer was also smaller in the 4-NQO + ONO-8711 (400 p.p.m. ONO-8711, 0.35 +/- 0.61; and 800 p.p.m. ONO-8711, 0.29 +/- 0.47; P<0.05), when compared with the 4-NQO alone group (0.88 +/- 0.88). Feeding with ONO-8711 significantly reduced PGE(2) level and cell proliferation activity in the non-tumorous epithelium of the tongue. Also, treatment with ONO-8711 resulted in the decrease in EP(1) immunohistochemical expression in the tongue lesions induced by 4-NQO. The results suggest that EP(1) receptor involves in oral carcinogenesis, and that an EP1-selective antagonist ONO-8711 exerts the cancer chemopreventive effects through the suppression of EP(1) expression, PGE(2) biosynthesis and cell proliferation.

4-Nitroquinoline-1-oxide↗
PubMed1995

Cross-adaptation of sweaty-smelling 3-methyl-2-hexenoic acid by a structurally-similar, pleasant-smelling odorant.

Cross-adaptation has been interpreted as a measure of the degree to which odors share common sensory channels. How structural similarity, in the absence of perceptual similarity, influences cross-adaptation is unknown. The present study assessed cross-adaptation by structurally similar, but perceptually different, odorants. Magnitude estimates for a 10:1 mixture of (E)- and (Z)-3-methyl-2-hexenoic acid (3M2H), a principal component of human underarm odor, decreased following adaptation to a mixture of (E)- and (Z)-ethyl esters of 3M2H (EE3M2H), which possess a pleasant, fruity odor. Cross-adaptation was asymmetric; adaptation to 3M2H did not significantly affect the perceived intensity of EE3M2H. By contrast, there was no significant cross-adaptation between 3M2H and the fruity-smelling ethyl esters of its homologues, 3-methyl-2-octenoic acid (EE3M20) and 3-methyl-2-pentenoic acid (EE3M2P). Similarity ratings revealed no differences among the three ethyl esters in their perceptual similarity to 3M2H (i.e. all were rated equally dissimilar to 3M2H). Molecular modeling studies revealed no difference in the charge distribution of these molecules. Rather, differences in the shape and size of the hydrophobic part of the molecule may determine the extent of cross-adaptation. These results demonstrate that structurally-similar, yet perceptually-distinct, odorants may cross-adapt and suggest that the extent of cross-adaptation may be affected by the degree of structural, as well as perceptual, similarity.

Adaptation, Physiological↗
PubMed2000

'Microsmatic' primates revisited: olfactory sensitivity in the squirrel monkey.

Using a conditioning paradigm, the olfactory sensitivity of three squirrel monkeys to nine odorants representing different chemical classes as well as members of a homologous series of substances was investigated. The animals significantly discriminated dilutions as low as 1:10,000 n-propionic acid, 1:30,000 n-butanoic acid and n-pentanoic acid, 1:100,000 n-hexanoic acid, 1:1Mio n-heptanoic acid, 1:30, 000 1-pentanol, 1:300,000 1,8-cineole, 1:1Mio n-heptanal and 1:30Mio amyl acetate from the near-odorless solvent, with single individuals scoring even slightly better. The results showed (i) the squirrel monkey to have an unexpectedly high olfactory sensitivity, which for some substances matches or even is better than that of species such as the rat or the dog, and (ii) a significant negative correlation between perceptibility in terms of olfactory detection thresholds and carbon chain length of carboxylic acids. These findings support the assumptions that olfaction may play a significant and hitherto underestimated role in the regulation of primate behavior, and that the concept of primates as primarily visual and 'microsmatic' animals needs to be revised.

Aldehydes↗
PubMed2006

Individual comparisons of the levels of (E)-3-methyl-2-hexenoic acid, an axillary odor-related compound, in Japanese.

The (E)-3-methyl-2-hexenoic acid (E3M2H), an axillary odor-related compound, is known to occur in Caucasians. The aims of this study were to clarify whether E3M2H contributes to axillary odor in Asians and to quantify and compare individual levels of E3M2H. Quantitative determination of E3M2H was performed by means of gas chromatography-mass spectrometry of sweat extracted from the axillary areas of T-shirts worn for 24 h by Japanese subjects. The amount of E3M2H was 15.9-34.6 nmol/ml in six of 30 subjects. Our method succeeded in quantitative analysis of E3M2H from axillary sweat collected individually; we also showed that E3M2H could be detected in Asians. This is the first report in which the amount of E3M2H in axillary sweat was quantified on an individual basis and compared to reveal individual differences. The results of this study indicate that E3M2H might contribute to axillary malodor in Asians as well as Caucasians.

Asian People↗
PubMed1994

Induction of phosphocholine-specific antibodies in X-linked immune deficient mice: in vivo protection against a Streptococcus pneumoniae challenge.

X-linked immune deficient (XID) mice are susceptible to infection with Streptococcus pneumoniae because they fail to mount an immune response to the immunodominant phosphocholine (PC) epitope on the bacterial cell wall. It is difficult to induce PC-specific antibodies in XID mice because PC-specific B cells expressing the T15-, M167- and M603 idiotype (Id), which provide protection against S. pneumoniae, are deleted in these mice via an antigen-specific, receptor-mediated process. In addition, the standard PC hapten, p-diazophenylphosphocholine (DPPC), induces high affinity phenylphosphocholine (PPC)-specific antibodies in XID mice, which are not protective against S. pneumoniae. We have used a novel PC hapten, p-nitrophenyl-6-(O-phosphocholine)hydroxyhexanoate (EPC), to induce PC-specific antibodies in XID mice. The immune response to EPC-keyhole limpet hemacyanin (KLH) is dominated by IgG1, VH1+, T15-Id-, PC-inhibitable antibodies. A small IgM anti-PC response having a consistent T15-Id+ component is also induced in XID mice, whereas normal mice produce a large IgM response dominated by T15-Id+ antibodies. The immune response to EPC-KLH remains predominantly PC-inhibitable even after multiple immunizations, while the response to DPPC-KLH becomes dominated by PPC-specific antibodies. C.CBA/N mice immunized twice with EPC-KLH are protected against 10(4) S. pneumoniae while as few as 10 bacteria are 100% lethal for the unimmunized controls. The ability of EPC-protein to induce a long-lived, PC-specific response should make this hapten a potential TD vaccine candidate for S. pneumoniae.

Animals↗
PubMed1997

Sequence changes at the V-D junction of the VH1 heavy chain of anti-phosphocholine antibodies alter binding to and protection against Streptococcus pneumoniae.

X-linked immune deficient (Xid) mice fail to produce anti-phosphocholine (PC) antibodies even after immunization with Streptococcus pneumoniae. Consequently, Xid mice are extremely susceptible to infection with S. pneumoniae, PC-specific B cells appear to undergo clonal deletion in Xid mice; however, a new thymus-dependent form of PC, 6-(O-phosphocholine)hydroxyhexanoate (EPC), can rescue PC-specific B cells from the bone marrow presumably by providing T cell help before clonal deletion. Analysis of PC-specific IgG hybridomas from Xid mice revealed utilization of several V-D junctional variants of the VH1 gene segment rearranged to different D and JH gene segments. The majority of Xid anti-PC antibodies exhibit an Asp-->Gly95H replacement at the V-D junction. These Gly95H VH1 variants associate with kappa 1C L chains to produce anti-PC antibodies that: (1) have low relative affinity for PC, (ii) are heteroclitic for nitrophenylphosphocholine and (iii) fall to bind to or provide protection against S. pneumoniae. Single prototypic V-D variants of the T15 idiotype (Asp95H), M603 idiotype (Asn95H) and M167 idiotype (Asp95H-Ala96H) were also induced in Xid mice. The M603-like and M167-like antibodies bound to and protected against S. pneumoniae even though they exhibited Kas for PC which were lower than T15 idiotype+ antibodies. These data demonstrate that small changes in the V-D junctional sequence of the T15 (VH1) heavy chain alter L chain usage and the structure of the PC binding site so that the PC expressed on S. pneumoniae is no longer recognized.

Amino Acid Sequence↗
PubMed2003

Polymeric carriers for amphotericin B: in vitro activity, toxicity and therapeutic efficacy against systemic candidiasis in neutropenic mice.

OBJECTIVE: To study the toxicity and activity of two new amphotericin B formulations: poly(epsilon-caprolactone) nanospheres coated with poloxamer 188 (AmB-NP) and mixed micelles with the same surfactant (AmB-MM). MATERIALS AND METHODS: The toxicity of these formulations was evaluated in erythrocytes, J774.2 macrophages and LLCPK1 renal cells, as well as in mice. Activity was determined in clinical isolates and in neutropenic mice. Mice were made neutropenic with 5-fluorouracil, infected with Candida albicans and treated with the antifungal formulations for three consecutive days. AmB association in cells and accumulation in kidneys and liver of animals was quantified by HPLC. RESULTS: Both formulations decreased between 8- and 10-fold the MIC of the polyene against clinical isolates of C. albicans. However, their activity was lower than or equal to that of AmB-deoxycholate when it was assessed against C. albicans-infected macrophages. When given as a single intravenous dose in mice, AmB-MM and AmB-NP had an LD50 of 9.8 and 18.6 mg/kg, respectively, compared with 4 mg/kg for AmB-deoxycholate. Comparison of residual infection burdens in the liver and kidneys showed that AmB-deoxycholate (0.5 mg/kg) was more effective and faster in eradicating yeast cells than polymeric formulations. This fact can be related to a lower AmB accumulation inside macrophages and in liver and kidneys (about 1.5 mg drug/g tissue) of mice, compared with those detected for AmB-deoxycholate (4 mg drug/g). Overall, the efficacy of these formulations at 2 mg/kg was equal to that of AmB-deoxycholate at 0.5 mg/kg. CONCLUSIONS: AmB-MM and AmB-NP decreased the in vivo antifungal activity of AmB, and higher concentrations were therefore necessary to obtain a similar therapeutic effect. However, these higher concentrations were achievable owing to the reduced toxicity of these formulations.

Amphotericin B↗
PubMed1975

Efficiency of alpha-ketoisocaproic acid as a substitute for leucine in the diet of the growing rat.

Immature male albino rats (70-80 g), eating a diet furnishing all nutrients for optimal growth and containing 84.6 mumoles of leucine/g, gained weight at an average rate of 5.9 g/day. Removal of leucine caused an average daily weight loss of 1.3 g. Addition of leucine to the diet in graduated amounts corrected this weight loss, the improvement in body weight (BW) being proportional to the dietary content of leucine. Addition of alpha-ketoisocaproic acid in place of leucine to the leucine-free diet also prevented loss of BW. Percentage efficiency of alpha-ketoisocaproic acid as a dietary substitute for leucine was calculated as: (see article). Efficiency of such substitution varied from 27% for a diet containing 84.6 mumoles of alpha-ketoisocaproic acid/g to 20% for a diet containing 169.2 alpha-ketoisocaproic acid/g.

Amino Acids, Essential↗
PubMed1979

Replacement of L-phenylalanine and L-leucine by alpha-hydroxy analogues in the diets of germfree rats.

It has been suggested that the metabolic activity of the intestinal microflora is necessary for the utilization of the alpha-keto and alpha-hydroxy analogues of the essential amino acids. This role of the intestinal microflora has been examined by comparing weight gain of germfree and conventional rats in response to the substitution of one amino acid in the diet by its analogue. Using a completely defined liquid diet it was found that weight gain of germfree rats was well maintained and comparable to that of conventional rats when 1.5 M equivalents of DL-alpha-hydroxyisocaproic acid was substituted for L-leucine in the diet. Although weight gain was not fully maintained when 2.0 M equivalents of L-phenyllactate was substituted for L-phenylalanine, germfree and conventional rats showed similar weight gains. These results exclude an obligatory role for the flora in the utilization of these non-nitrogen containing analogues of L-phenylalanine and L-leucine.

Animals↗
PubMed1982

Comparative utilization of the alpha-keto and D- and L-alpha-hydroxy analogs of leucine, isoleucine and valine by chicks and rats.

Several experiments were conducted to quantitatively evaluate the growth-promoting capacity of the isomers of the branched-chain amino acids (BCAA) and their alpha-hydroxy and alpha-keto analogs for the chick and rat. Basal chemically defined diets were formulated to be singly deficient in the BCAA under study; analogs therefore were evaluated as sources of supplemental amino acid activity. DL-Isoleucine (DL-Ile), alpha-keto-beta-L-methylvaleric acid (KMV) and the isomers of alpha-hydroxy-beta-methylvaleric acid (HMV) were inferior to an isomolar level of L-Ile and varied considerably in their capacity to support growth of chicks and rats. Efficacy values of the compounds for chicks (C) and rats (R) were: DL-Ile 85% (C), 58% (R); KMV 60% (C), 38% (R); L-HMV 84% (C), 65% (R); DL-HMV 49% (C), 45% (R); and D-HMV -10% (C), -2% (R). The isomers of valine (Val) and alpha-hydroxyisovaleric acid (HIV) had efficacy values in chicks of: DL-Val, 84%; D-Val, 72%; L-HIV, 82%; DL-HIV, 79%; D-HIV, 66%. D-Val had only marginal growth-promoting activity for rats, 16%. All Val analogs had comparable efficacy values for the rat: alpha-ketoisovaleric acid (KIV), 49%; L-HIV, 54%; DL-HIV, 51%; and D-HIV, 46%. DL-Leu and D-Leu, alpha-ketoisocaproic acid (KIC), and L-, DL- and D-alpha-hydroxyisocaproic acid (HIC) were all less efficacious than isomolar amounts of supplemental L-Leu in rats. Efficacy values were: DL-Leu, 78%; D-Leu, 48%; KIC, 56%; L-HIC, 58%; DL-HIC, 55%; and D-HIC, 41%. The BCAA keto analogs were not superior to the L-alpha-hydroxy analogs in growth-promoting capacity, and this is of great interest for the potential use of these nitrogen-free amino acid analogs in nutritional therapy.

Animals↗
PubMed1994

Emulsification and fatty acid chain length affect the kinetics of [14C]-medium-chain triacylglycerol utilization by neonatal piglets.

In vivo oxidation kinetics of medium-chain triglycerides (MCT) composed of [1-14C]hexanoate (tri-6:0) or [1-14C]octanoate (tri-8:0) were compared after being fed to day-old piglets (1.4 kg; n = 4/treatment). Animals were fitted with arterial and oro-gastric catheters and placed into respiration chambers held at 35 degrees C. The radiolabeled MCT were fed in equimolar amounts (6.5 mmol/kg0.75), in either nonemulsified form or as 30% (v/v) emulsions, using polyoxyethylene sorbitan monooleate as an emulsifier. Expired CO2 was quantified and specific radioactivity (Bq/mumol) determined at 20-min intervals over 24 h, and serial blood samples were drawn for measurement of plasma hexanoate and octanoate by HPLC. The rate [mumol/(h.kg0.75)] and extent (mmol/kg0.75) of MCT oxidative utilization (i.e., composite of digestion, absorption and oxidation) were calculated from the kinetics of 14CO2 expiration. Emulsification increased both the rate and extent of MCT oxidative utilization by > 20% regardless of fatty acid chain length (P < 0.05). Maximal MCT oxidation rates occurred at 3.5 h after feeding and were sufficient to meet up to 48% of the piglets' energy expenditure. The maximal rate of tri-6:0 oxidative utilization exceeded that of tri-8:0 by 37% (P < 0.05), but the extent of utilization was not affected by fatty acid chain length. Plasma medium-chain fatty acid concentrations were in agreement with these observations, being higher in pigs fed emulsified MCT than in pigs fed nonemulsified MCT (P < 0.05) and being higher in pigs fed tri-6:0 than in animals fed tri-8:0 (P < 0.05). Collectively, these data demonstrate that newborn piglets can effectively digest, absorb and oxidize MCT, that utilization is improved with emulsification, and that tri-6:0 is utilized more rapidly than tri-8:0.

Analysis of Variance↗
PubMed2000

Tricaproin, tricaprin and trilaurin are utilized more efficiently than tricaprylin by carp (Cyprinus carpio L.) larvae.

We investigated the effect of chain length of dietary medium-chain fatty acids (MCFA) on growth performance and fatty acid composition of first-feeding carp larvae. In a first trial, five semi-purified isolipidic (23-24 g/100 g of dry matter) diets were formulated to contain either 10 g/100 g triolein (control diet) or 5 g/100 g triolein and 5 g/100 g medium-chain triacylglycerols (MCT) supplied as tricaproin, tricaprylin, tricaprin or trilaurin. After 21 d, survival and growth rates were significantly greater in larvae fed diets containing triolein, tricaproin, tricaprin and trilaurin (final survival: 92 +/- 7% and mean larval weight: 42 +/- 15 mg) than in larvae fed tricaprylin (final survival: 56 +/- 12% and mean larval weight: 15 +/- 1 mg). The recovered levels of the fed MCFA in larval total lipids were respectively 0, 1.3, 7.3 and 8.1 g/100 g of total fatty acids. In a second trial, two isolipidic (18 g/100 g) diets containing 10 g/100 g triolein or tricaprylin were tested. High amounts of capric acid (up to 25 g/100 g of total fatty acids) were found in neutral lipids of carp larvae fed tricaprylin for 11 d, suggesting an unusual elongation of caprylic acid. This study underlines the peculiarity of tricaprylin among other MCT which seem well utilized up to 20-30 g/100 g of total dietary fatty acids. The exception of tricaprylin raises the question of the metabolic pathways followed by this MCT, especially for the suggested direct elongation of caprylic acid into capric acid.

Animal Feed↗