Dried plum diet protects from bone loss caused by ionizing radiation.

Bone loss caused by ionizing radiation is a potential health concern for radiotherapy patients, radiation workers and astronauts. In animal studies, exposure to ionizing radiation increases oxidative damage in skeletal tissues, and results in an imbalance in bone remodeling initiated by increased bone-resorbing osteoclasts. Therefore, we evaluated various candidate interventions with antioxidant or anti-inflammatory activities (antioxidant cocktail, dihydrolipoic acid, ibuprofen, dried plum) both for their ability to blunt the expression of resorption-related genes in marrow cells after irradiation with either gamma rays (photons, 2 Gy) or simulated space radiation (protons and heavy ions, 1 Gy) and to prevent bone loss. Dried plum was most effective in reducing the expression of genes related to bone resorption (Nfe2l2, Rankl, Mcp1, Opg, TNF-α) and also preventing later cancellous bone decrements caused by irradiation with either photons or heavy ions. Thus, dietary supplementation with DP may prevent the skeletal effects of radiation exposures either in space or on Earth.

The microbiome and colorectal neoplasia: environmental modifiers of dysbiosis.

The etiology of colon cancer is complex, yet it is undoubtedly impacted by intestinal microbiota. Whether the contribution to colon carcinogenesis is generated through the presence of an overall dysbiosis or by specific pathogens is still a matter for debate. However, it is apparent that interactions between microbiota and the host are mediated by a variety of processes, including signaling cascades, the immune system, host metabolism, and regulation of gene transcription. To fully appreciate the role of microbiota in colon carcinogenesis, it will be necessary to expand efforts to define populations in niche environments, such as colonic crypts, explore cross talk between the host and the microbiota, and more completely define the metabolomic profile of the microbiota. These efforts must be pursued with appreciation that dietary substrates and other environmental modifiers mediate changes in the microbiota, as well as their metabolism and functional characteristics.

Quercetin Suppresses Early Colon Carcinogenesis Partly through Inhibition of Inflammatory Mediators.

We have demonstrated that 0.45% quercetin added to a diet containing corn oil (15% w/w), as the lipid source, and cellulose (6% w/w), as the fiber source, was able to suppress the formation of high multiplicity aberrant crypt foci (ACF > 4 AC/focus), to lower proliferation and enhance apoptosis in a rat model of colon cancer. This experiment determined whether quercetin was acting as an antiinflammatory molecule in an in vivo model of colon cancer. We used weanling (21 d old) Sprague Dawley rats (n = 40) in a 2×2 factorial experiment to determine the influence of quercetin on iNOS, COX-1 and COX-2 expressions, all of which are elevated in colon cancer. Half of the rats received a diet containing either 0 or 0.45% quercetin, and within each diet group, half of the rats were injected with saline or azoxymethane (AOM, 15 mg/kg BW, sc, 2× during wk 3 and 4). The colon was resected 4 wk after the last AOM injection, and the mucosa scraped and processed for RNA isolation. Data from this experiment were analyzed using a mixed model in SAS for main effects and their interaction. AOM injection stimulated (P < 0.0001) iNOS expression. However there was an interaction such that, relative to rats injected with saline, AOM-injected rats consuming diets without quercetin had significantly elevated iNOS expression (5.29-fold), but the expression in AOM-injected rats consuming the diet with quercetin was not significantly elevated (1.68-fold). COX-1 expression was 20.2% lower (P < 0.06) in rats consuming diets containing quercetin. COX-2 expression was 24.3% higher (P < 0.058) in rats consuming diets without quercetin. These data suggest inflammatory processes are elevated in this early stage of colon carcinogenesis, yet quercetin may protect against colon carcinogenesis by down-regulating the expressions of COX-1 and COX-2.

Dietary fish oil and pectin enhance colonocyte apoptosis in part through suppression of PPARdelta/PGE2 and elevation of PGE3.

We have shown that dietary fish oil and pectin (FP) protects against radiation-enhanced colon cancer by upregulating apoptosis in colonic mucosa. To investigate the mechanism of action, we provided rats (n = 40) with diets containing the combination of FP or corn oil and cellulose (CC) prior to exposure to 1 Gy, 1 GeV/nucleon Fe-ion. All rats were injected with a colon-specific carcinogen, azoxymethane (AOM; 15 mg/kg), 10 and 17 days after irradiation. Levels of colonocyte apoptosis, prostaglandin E(2) (PGE(2)), PGE(3), microsomal prostaglandin E synthase-2 (mPGES-2), total beta-catenin, nuclear beta-catenin staining (%) and peroxisome proliferator-activated receptor delta (PPARdelta) expression were quantified 31 weeks after the last AOM injection. FP induced a higher (P < 0.01) apoptotic index in both treatment groups, which was associated with suppression (P < 0.05) of antiapoptotic mediators in the cyclooxygenase (COX) pathway (mPGES-2 and PGE(2)) and the Wnt/beta-catenin pathway [total beta-catenin and nuclear beta-catenin staining (%); P < 0.01] compared with the CC diet. Downregulation of COX and Wnt/beta-catenin pathways was associated with a concurrent suppression (P < 0.05) of PPARdelta levels in FP-fed rats. In addition, colonic mucosa from FP animals contained (P < 0.05) a proapoptotic, eicosapentaenoic acid-derived COX metabolite, PGE(3). These results indicate that FP enhances colonocyte apoptosis in AOM-alone and irradiated AOM rats, in part through the suppression of PPARdelta and PGE(2) and elevation of PGE(3). These data suggest that the dietary FP combination may be used as a possible countermeasure to colon carcinogenesis, as apoptosis is enhanced even when colonocytes are exposed to radiation and/or an alkylating agent.

Anatomical site-specific response to DNA damage is related to later tumor development in the rat azoxymethane colon carcinogenesis model.

There is now general agreement that the etiology of proximal and distal colon cancers may differ, thus prompting renewed interest in understanding anatomical site-specific molecular mechanisms of tumor development. Using a 2x2x2 factorial design with male Sprague-Dawley rats (corn oil, fish oil; pectin, cellulose; plus or minus azoxymethane injection) we found a greater than 2-fold difference (P < 0.001) in tumor incidence proximally versus distally (prox/dist ratio: corn oil, 2.25; fish oil, 2.61). The purpose of the present study was to determine if the higher degree of proximal versus distal tumors in our model system could be accounted for by differences between these two sites in initial DNA damage, response to that damage or an effect of diet at one site but not the other. DNA damage was assessed by quantitative immunohistochemistry of O(6)-methylguanine adducts; repair by measurement of O(6)-methylguanine-DNA alkyltransferase and removal was determined by measurement of targeted apoptosis. Although overall initial DNA damage was similar at both sites, in the distal colon there was a greater expression of repair protein (P < 0.001) and a greater degree of targeted apoptosis (P < 0.0001). There was also a reduction in DNA damage in the distal colon of rats consuming fish oil. Together, these results suggest that the lower tumor incidence in the distal colon may be a result of the capacity to deal with initial DNA damage by the distal colon, as compared with the proximal colon. Therefore, the determination of site-specific mechanisms in tumor development is important because distinct strategies may be required to protect against cancer at different sites.

Physical and mechanical characteristics of tibias from transgenic mice expressing mutant bovine growth hormone genes.

Physical and mechanical characteristics of tibia from mice expressing either the M4, M11, or G119K mutant bovine growth hormone (bGH) gene and displaying large, near-normal, or small-size phenotypes, respectively, were compared to those of non-transgenic, control mice (NTC). Three animals of each strain were euthanized at 28, 38, 48, 58, and 68 days of age. Variables were regressed against age to establish the pattern of change throughout the experiment, and the regression results are presented. Tibias from G119K were shorter (13.1 mm) and lighter (37.3 mg) than those from other strains, and M4 tibias were heavier (87.9 mg) and longer (16.6 mm) at 70 days of age. The ratio of tibia length to body weight suggests longitudinal bone growth was not reduced as much as overall growth in G119K mice. The external and internal dimensions of the G119K tibias were smaller than the other strains whereas the M4 tibias were somewhat larger. Differences in physical dimensions between the NTC and M11 mice did not greatly affect bone mechanical characteristics. Tibias from M4 mice resisted more load at both flexure and breaking compared to the other strains. At 50 days of age, stress at flexure was greater at all ages for G119K mice (12.4 kg/mm2) and was decreased in M4 mice (8.5 kg/mm2). The bGH mutations produce different effects on bone growth and its mechanical characteristics. There also may be differential tissue responsiveness to the mutant bGH analogs, as longitudinal growth was not as affected as empty body growth in the G119K mice. These transgenic mouse strains provide valuable models to study bone growth, formation, and reformation in response to GH regulation, and more importantly, the M4 and G119K mice may serve as a model in which the priorities for GH action on bone vs muscle may be determined.

Morphodensitometric analysis of protein kinase C beta(II) expression in rat colon: modulation by diet and relation to in situ cell proliferation and apoptosis.

We have recently demonstrated that overexpression of PKC beta(II) renders transgenic mice more susceptible to carcinogen-induced colonic hyperproliferation and aberrant crypt foci formation. In order to further investigate the ability of PKC beta(II) to modulate colonocyte cytokinetics, we determined the localization of PKC beta(II) with respect to cell proliferation and apoptosis along the entire colonic crypt axis following carcinogen and diet manipulation. Rats were provided diets containing either corn oil [containing n-6 polyunsaturated fatty acids (PUFA)] or fish oil (containing n-3 PUFA), cellulose (non-fermentable fiber) or pectin (fermentable fiber) and injected with azoxymethane (AOM) or saline. After 16 weeks, an intermediate time point when no macroscopic tumors are detected, colonic sections were utilized for immunohistochemical image analysis and immunoblotting. Cell proliferation was measured by incorporation of bromodeoxyuridine into DNA and apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling. In the distal colon, PKC beta(II) staining was localized to the upper portion of the crypt. In comparison, proximal crypts had more (P < 0.05) staining in the lower tertile. AOM enhanced (P < 0.05) PKC beta(II) expression in all regions of the distal colonic crypt (upper, middle and lower tertiles). There was also an interaction (P < 0.05) between dietary fat and fiber on PKC beta(II) expression (corn/pectin > fish/cellulose, fish/pectin > corn/cellulose) in all regions of the distal colonic crypt. With respect to colonic cell kinetics, proliferation paralleled the increase in PKC beta(II) expression in carcinogen-treated animals. In contrast, apoptosis at the lumenal surface was inversely proportional to PKC beta(II) expression in the upper tertile. These results suggest that an elevation in PKC beta(II) expression along the crypt axis in the distal colon is linked to enhancement of cell proliferation and suppression of apoptosis, predictive intermediate biomarkers of tumor development. Therefore, select dietary factors may confer protection against colon carcinogenesis in part by blocking carcinogen-induced PKC beta(II) expression.

Relationship between DNA adduct levels, repair enzyme, and apoptosis as a function of DNA methylation by azoxymethane.

DNA alkylating agent exposure results in the formation of a number of DNA adducts, with O6-methyl-deoxyguanosine (O6-medG) being the major mutagenic and cytotoxic DNA lesion. Critical to the prevention of colon cancer is the removal of O6-medG DNA adducts, either through repair, for example, by O6-alkylguanine-DNA alkyltransferase (ATase) or targeted apoptosis. We report how rat colonocytes respond to administration of azoxymethane (a well-characterized experimental colon carcinogen and DNA-methylating agent) in terms of O6-medG DNA adduct formation and adduct removal by ATase and apoptosis. Our results are: (a) DNA damage is greater in actively proliferating cells than in the differentiated cell compartment; (b) expression of the DNA repair enzyme ATase was not targeted to the proliferating cells or stem cells but rather is confined primarily to the upper portion of the crypt; (c) apoptosis is primarily targeted to the stem cell and proliferative compartments; and (d) the increase in DNA repair enzyme expression over time in the bottom one-third of the crypt corresponds with the decrease in apoptosis in this same crypt region.

Antagonism of CD95 signaling blocks butyrate induction of apoptosis in young adult mouse colonic cells.

There is great interest in utilizing butyrate as a chemopreventive agent for colon tumorigenesis because of its ability to promote apoptosis in colon tumor cell lines. Because CD95 (APO-1/Fas) transduces signals resulting in apoptosis, we tested the hypothesis that butyrate-dependent colonocyte apoptosis is mediated by this death receptor. Butyrate (1 mM) exposure for 24 h upregulated expression of Fas and its ligand in young adult mouse colon (YAMC) cells. To delineate the proapoptotic effect of butyrate and to avoid the confounding effects of detachment from the extracellular matrix, adherent cell apoptosis was monitored as loss of plasma membrane asymmetry and dissipation of mitochondrial membrane potential (DeltaPsi(mt)) by laser cytometry. Soluble Fas receptor protein (Fas:Fc chimera) and caspase inhibitors (z-VAD-fmk and z-IETD-fmk) blocked butyrate induction of apoptosis. Treatment with Fas agonistic antibody (clone Jo-2) significantly induced cell death, indicating that Fas in colonocytes is functional. In addition, butyrate promoted apoptosis by inducing loss of DeltaPsi(mt) and phospholipid asymmetry of the plasma membrane after 12 and 24 h of exposure, respectively, before cell detachment. Therefore, Fas receptor-dependent signal transduction is involved in butyrate induction of apoptosis in colonocytes.

Potential protective mechanisms of wheat bran fiber.

Experimental studies using high-fiber supplements show that of all the fibers tested, wheat bran is the most effective in protecting against colon tumor development. The mechanisms behind this protective effect have not been elucidated completely, and the effect is most likely multifactorial. Some mechanisms, such as luminal dilution of potential carcinogens and accelerated transit through the colon, are well established. The fermentation of wheat fiber to short-chain fatty acids--especially butyric, which has been shown to inhibit tumor growth in vitro--is documented, but interpretation of the data from animal studies and clinical trials is subject to debate. Several potential mechanisms, such as effects of phytochemicals and phytates contained in wheat bran, have not yet been explored.

Expression of mutant bovine growth hormone genes in mice perturbs age-related nutrient utilization patterns.

Three lines of transgenic mice expressing mutant bovine growth hormone (bGH) genes and displaying small (G119K), near normal (M11) or large (M4) phenotypes and nontransgenic control (NTC) mice were used to determine GH-associated, age-specific changes in empty body composition. The single amino acid substitution in G119K mice reduced the quantities (P < 0.001) and early rates (P < 0.05) of deposition for water, protein and ash but resulted in similar quantities of fat as the NTC mice. The change in relative quantities of empty body components indicated the G119K analogue altered nutrient partitioning, basal metabolism and (or) nutrient availability to effect the differential observed in body composition. The two amino acid substitutions in the bGH gene expressed by the M11 mice caused only a small change in phenotype, but age-related changes in the accretion of protein, fat and ash indicated these mice were not mature by 68 d of age. The bGH analogue produced by the M4 mice resulted in a doubling (P < 0.001) of body weight in comparison with the NTC mice, a result of the increasing (P < 0.001) rate of weight gain. Empty body component gain of the M4 mice also indicated they had not yet matured by 68 d of age. The G119K and M4 mutant forms of bGH altered rates and composition of growth, possibly through redirection of tissue nutrient utilization, modification of nutrient metabolism, and(or) nutrient availability.

Non-invasive detection of fecal protein kinase C betaII and zeta messenger RNA: putative biomarkers for colon cancer.

We have developed a non-invasive method utilizing feces, containing sloughed colonocytes, as a sensitive technique for detecting diagnostic colonic biomarkers. In this study, we used the rat colon carcinogenesis model to determine if changes in fecal protein kinase C (PKC) expression have predictive value in monitoring the neoplastic process. Weanling rats were injected with saline or azoxymethane (AOM) and 36 weeks later fecal samples and mucosa were collected, poly A+ RNA isolated, and quantitative RT-PCR performed using primers to PKC betaII and zeta. Fecal PKC betaII and zeta mRNA levels were altered by the presence of a tumor, with tumor-bearing animals having a 3-fold higher (P < 0.05) PKC betaII expression as compared with animals without tumors. In addition, AOM-injection increased mucosal PKC betaII mRNA expression compared with saline controls. No effect of tumor incidence on mucosal PKC betaII expression was observed. In contrast, fecal PKC zeta expression was 2.5-fold lower (P < 0.05) in animals injected with azoxymethane versus saline. Since tumor incidence exerts a reciprocal effect on fecal PKC betaII and zeta mRNA expression, data were also expressed as the ratio between PKC betaII and zeta. The isozyme ratio was strongly related to tumor incidence, i.e. ratio for animals with tumors was 2.18 +/- 1.25, animals without tumors was 0.50 +/- 0.16, P = 0.025. We demonstrate that the expression of fecal PKC betaII and zeta may serve as a noninvasive marker for development of colon tumors. A sensitive technique for the detection of colon cancer is of importance since early diagnosis can substantially reduce mortality.

Wheat bran diet reduces tumor incidence in a rat model of colon cancer independent of effects on distal luminal butyrate concentrations.

To investigate the effects of dietary fibers in colonic luminal physiology and their role in the prevention of colon cancer, a study was conducted using two diet groups and two treatment groups in a 2 x 2 factorial design. The two diets differed only in the type of dietary fiber, wheat bran and oat bran, and the two treatments were injection with the colon-specific carcinogen azoxymethane, or saline, as a control. There were 34 rats in the carcinogen-injected groups and 11 saline-injected rats per diet group. The goal of the study was to determine if a moderate consumption (6 g/100 g diet) of wheat bran or oat bran would alter the development of colonic tumors in this rat model of colon cancer, and if the differences in tumor incidence were correlated to luminal butyrate concentrations, luminal pH or fecal bulk. Short-chain fatty acid concentrations (SCFA) were measured in feces during the first half of the study (the promotion phase of tumor development) and again at the end of the study. Rats consuming oat bran had greater body weights (P < 0. 002), produced much larger concentrations of all SCFA, including butyrate, in both the proximal and distal colon (P < 0.0001), had more acidic luminal pH values (P < 0.0001), but also had significantly more development of colon tumors (P < 0.03). Alternatively, rats consuming wheat bran produced more typical molar ratios of the SCFA (65:10:20), had a relatively greater concentration of butyrate than propionate, and produced a larger volume (P < 0.05) and more bulky stool than the rats fed oat bran. The results of this study support other evidence that an acidic luminal pH is not protective in and of itself, and that diets containing wheat bran are protective against colon cancer development. In addition, these data show that large luminal butyrate concentrations in the distal colon alone, as were present in the rats consuming oat bran diets, are not protective of tumor development.

Diet and carcinogen alter the fecal microbial populations of rats.

An analysis of viable bacterial populations enumerated on carbohydrate selective media was used to simulate the colonic environment in vitro and determine if differential media could detect significant microbial shifts due to dietary fiber source, dietary fat source, and carcinogen. Male Sprague-Dawley rats were provided with either pectin or cellulose as a fiber source, either corn or fish oil as a source of fatty acids, and injected with either azoxymethane (AOM), a gastrointestinal carcinogen, or saline in a 2 x 2 x 2 factorial design. At 6 and 10 mo of age, fresh feces were collected, homogenized in anaerobic buffer and anaerobically plated onto differential media. Diets containing pectin supported more anaerobes at 6 mo of age (P < 0.01) than diets containing cellulose. Rats injected with AOM and consuming either pectin or corn oil supported more anaerobes at 10 mo of age (P < 0.05) than rats injected with saline and consuming the same diets. Rats consuming cellulose and receiving AOM but not expressing tumors possessed larger anaerobic populations at 10 mo of age (P < 0.05) than rats consuming cellulose, injected with AOM and expressing tumors. These effects show that gastrointestinal bacterial populations, as measured by carbohydrate specific media, respond to dietary changes such as dietary fiber source, and thus may play a key role in the etiology of colon cancer.

Children's literature for the primary inclusive classroom: increasing understanding of children with hearing impairments.

As a result of recent federal legislation and positive research findings of educators, children with disabilities, including hearing impairment, are being included in general education classrooms. This development has many implications at the state, district, and classroom levels. While helping the child with disabilities assimilate into the general education classroom may appear to be the teacher's primary challenge, increasing awareness and understanding among those students without disabilities is a growing concern of educators. The use of children's literature featuring children with disabilities is one way to promote this understanding. This article includes an annotated bibliography of children's literature featuring children with hearing impairment, along with related classroom activities to enhance experiences with the books.

Physiological and hormonal responses of lambs repeatedly implanted with zeranol and provided two levels of feed intake.

Forty crossbred wethers (average weight 30 kg) were implanted with zeranol (12 mg) at 30-d intervals and fed at two levels of intake in a 2 x 2 factorial arrangement of treatments to determine performance, carcass and bone characteristics, blood metabolites, and hormones. Restricted lambs were fed to gain one-half the BW gained by lambs with ad libitum feed access. Lambs with ad libitum and restricted access to feed were slaughtered after 98 and 154 d, respectively. Zeranol increased ADG (P = .047; 20%), gain to feed (P = .023; 17%), metacarpal length (P = .004; 6%) and weight (P = .013; 13%), and tended to increase carcass crude protein gain (P = .106; 63%) while reducing kidney pelvic fat (P = .001; 33%) and dressing percentage (P = .038; 3%). Restricted feed intake increased the percentage of carcass ash and metacarpal length and weight by 27% (P = .048), 5% (P = .006), and 10% (P = .045), respectively, while reducing quality grade scores (P = .022; 5%), gain to feed (P = .001; 49%), longissimus muscle area (P = .001; 28%), the percentage of kidney pelvic fat (P = .033; 13%), and daily fat gain (P = .001; 54%). Zeranol increased pituitary weight (P = .001; 166%), plasma glucose (P = .036; 13%), mean serum growth hormone (GH; P = .011; 52%), baseline GH (P = .048; 34%), GH pulse amplitude (P = .003; 59%), and IGF-I (P = .001; 53%) concentrations. The results indicate that continuous administration of zeranol from 60 d of age to slaughter increases GH release, which directs nutrient utilization such that a carcass with more desirable lean and fat deposition patterns is obtained when nutrient availability is adequate.

Influence of incremental zeranol implant doses on the chemical and physical characteristics of third metacarpal bone and chemical composition of liver and soft tissue from feedlot steers.

Chemical and physical characteristics of third metacarpal bones and liver and rib soft tissue composition from feedlot steers were determined. Steers were selected (32 from each experimental location) to represent the range in slaughter weight and composition for each treatment group in three (total n = 1,088) feedlot experiments. Steers were implanted with 0, 24, 36, 48, 60, 72, 84, or 96 mg of zeranol at approximately 140 d before slaughter. Cattle at each location were fed for the same number of days and slaughtered as a group. Zeranol dose had no effect on the chemical composition of bone, liver, or rib soft tissue with the following exceptions: zeranol decreased (P < .01) bone Ca concentration and increased (P < .07) liver P concentration. Zeranol implantation decreased medullary cavity anterioposterior (AP) diameters and AP cortical width (P < .08). Loads withstood by the bones up to flexure (P < .08) and the strain at flexure (P < .09) were inversely related to the quadratic of zeranol dose. However, modulus of elasticity at flexure and breaking increased numerically with zeranol dose. Stress withstood by bones at flexure was greater (P < .09) for implanted steers. Strain data indicate that metacarpals from steers receiving zeranol would exhibit less deformation upon loading to flexure (P < .09) than controls. These data indicate that administration of intermediate doses of zeranol altered bone deposition of Ca, which resulted in modified third metacarpal physical and mechanical characteristics.

Growth patterns and body composition of transgenic mice expressing mutated bovine somatotropin genes.

The objectives of this study were to determine growth rates, feed intakes, feed efficiencies, and chemical composition of mice from three transgenic lines in 10-d periods from weaning to near maturity. Lines M4, M11, and G119K express bovine somatotropin (bST) mutations E117L, L121P-E126G, and G119K and display phenotypes of large, near normal, and small body size, respectively. M4 mice were 28% larger at 28 d and 84% larger at 68 d than non-transgenic control (NTC) mice. M11 mice were the same size at 28 d as NTC but were 25% larger at 68 d. G119K mice were 34% and 25% smaller than NTC at 28 and 68 d, respectively. Growth rates of G119K mice and NTC were similar, whereas growth rates of M11 and M4 mice were increased (P < .05). Feed intakes of M4 and M11 mice were greater than those of NTC mice (P < .05), whereas feed intakes of G119K mice were lower than those of NTC mice (P < .05). Feed efficiency (gain/feed) was improved in M4 and M11 mice (P < .05) and not altered in G119K mice compared to that of NTC mice (P > .05). Chemical composition was also altered by expression of bST analogs in transgenic mice. G119K and M4 mice had increased body fat percentages and decreased body protein percentages in comparison to M11 and NTC mice (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Method for the analysis of S9788, a drug to reverse resistance to anticancer agents, in animal plasma and human plasma and serum by high-performance liquid chromatography with ultraviolet detection.

An extraction method has been developed using benzene sulphonyl cation-exchange sample preparation cartridges and reversed-phase high-performance liquid chromatography with ultraviolet detection for the measurement of S9788, a drug to reverse resistance to anticancer agents, in plasma and serum. This includes a toxicokinetic assay which has a mean precision and accuracy of 11.7% and 7.9%, respectively, over the range 10-1000 ng ml-1 and a quantification limit of 10 ng ml-1 and a more sensitive pharmacokinetic procedure with a mean precision and accuracy of 5.0% and 7.9%, respectively, over the range 1-500 ng ml-1 and a quantification limit of 1 ng ml-1. The specificity of the procedure has been demonstrated by mass and ultraviolet spectrometry, and linearity, precision, accuracy, recovery and sensitivity have been established. The assays have been successfully applied to toxicokinetic and pharmacokinetic studies.