Detection of hepatotoxicity potential with metabolite profiling (metabolomics) of rat plasma.

While conventional parameters used to detect hepatotoxicity in drug safety assessment studies are generally informative, the need remains for parameters that can detect the potential for hepatotoxicity at lower doses and/or at earlier time points. Previous work has shown that metabolite profiling (metabonomics/metabolomics) can detect signals of potential hepatotoxicity in rats treated with doxorubicin at doses that do not elicit hepatotoxicity as monitored with conventional parameters. The current study extended this observation to the question of whether such signals could be detected in rats treated with compounds that can elicit hepatotoxicity in humans (i.e., drug-induced liver injury, DILI) but have not been reported to do so in rats. Nine compounds were selected on the basis of their known DILI potential, with six other compounds chosen as negative for DILI potential. A database of rat plasma metabolite profiles, MetaMap(®)Tox (developed by metanomics GmbH and BASF SE) was used for both metabolite profiles and mode of action (MoA) metabolite signatures for a number of known toxicities. Eight of the nine compounds with DILI potential elicited metabolite profiles that matched with MoA patterns of various rat liver toxicities, including cholestasis, oxidative stress, acetaminophen-type toxicity and peroxisome proliferation. By contrast, only one of the six non-DILI compounds showed a weak match with rat liver toxicity. These results suggest that metabolite profiling may indeed have promise to detect signals of hepatotoxicity in rats treated with compounds having DILI potential.

Prediction of clinically relevant safety signals of nephrotoxicity through plasma metabolite profiling.

Addressing safety concerns such as drug-induced kidney injury (DIKI) early in the drug pharmaceutical development process ensures both patient safety and efficient clinical development. We describe a unique adjunct to standard safety assessment wherein the metabolite profile of treated animals is compared with the MetaMap Tox metabolomics database in order to predict the potential for a wide variety of adverse events, including DIKI. To examine this approach, a study of five compounds (phenytoin, cyclosporin A, doxorubicin, captopril, and lisinopril) was initiated by the Technology Evaluation Consortium under the auspices of the Drug Safety Executive Council (DSEC). The metabolite profiles for rats treated with these compounds matched established reference patterns in the MetaMap Tox metabolomics database indicative of each compound's well-described clinical toxicities. For example, the DIKI associated with cyclosporine A and doxorubicin was correctly predicted by metabolite profiling, while no evidence for DIKI was found for phenytoin, consistent with its clinical picture. In some cases the clinical toxicity (hepatotoxicity), not generally seen in animal studies, was detected with MetaMap Tox. Thus metabolite profiling coupled with the MetaMap Tox metabolomics database offers a unique and powerful approach for augmenting safety assessment and avoiding clinical adverse events such as DIKI.

Dizygotic monochorionic twin pregnancy conceived following intracytoplasmic sperm injection treatment and complicated by twin-twin transfusion syndrome and blood chimerism.

We report a case of a dizygotic monochorionic twin pregnancy preceded by intracytoplasmic sperm injection treatment including assisted hatching. On ultrasound examination at 25 weeks' gestation the twins, which had been assumed to be monochorionic, were found to be of different sexes. Karyotyping and zygocity determination were performed on amniotic fluid and showed the twins to be dizygotic with normal female and male karyotypes. There were clinical and sonographic signs of twin-twin transfusion syndrome (TTTS), and Cesarean delivery was performed at 32 weeks' gestation. At birth the twins were phenotypically a normal male and a normal female. Histology of the placenta showed it to be monochorionic diamniotic. Blood chimerism was found postnatally as both infants had the karyotypes 46,XX[13]/46,XY[17]. Chimerism was not found in cells from a buccal swab at 6 months of age. This is one of only a few reported cases of dizygotic monochorionic twins. Nearly all of these cases have been conceived after assisted reproductive technology procedures. It is of clinical importance to be aware of this rare phenomenon in relation to TTTS, prenatal screening and parental counseling.

Rational design of platinum chemotherapeutic drugs: hydrophobicity increases cytotoxicity.

BACKGROUND: Malignant glioma are often resistant to cisplatin. Numerous chemical modifications have been made to overcome this limitation. Analyzing such novel compounds, we previously hypothesized, that hydrophobicity improves the cytotoxicity of NH3 substituted platinum agents. MATERIALS AND METHODS: Testing this hypothesis, we synthesized further eight novel platinum agents, substituting the NH3 groups with various pyridyl ring systems. The cytotoxicity was measured in MTT tests using the cisplatin resistant human U25 1 malignant glioma cell line as a model. Solubility was measured in water using flameless atomic absorption spectroscopy. RESULTS: Cytotoxicity correlated significantly with low water solubility. The relation of cells surviving 72-hours of 1 OuM drug exposure was best described by a logarithmic formula: Surviving cells (% of control) = 6.4 + 38.4 log (water solubility in mg Pt/L) Adding an oximgroup to the aromatic substitute decreased cytotoxicity. CONCLUSIONS: These data confirmed that increased hydophobicity increases cytotoxicity in this group. This might be caused by better cellular penetration, or by shielding of DNA-adducts from repair processes. The data created a further hypothesis: A positive mesomeric effect as characteristic for the oxim-group might decrease DNA binding, a negative mesomeric might improve it.

A novel MHC class I-like gene is mutated in patients with hereditary haemochromatosis.

Hereditary haemochromatosis (HH), which affects some 1 in 400 and has an estimated carrier frequency of 1 in 10 individuals of Northern European descent, results in multi-organ dysfunction caused by increased iron deposition, and is treatable if detected early. Using linkage-disequilibrium and full haplotype analysis, we have identified a 250-kilobase region more than 3 megabases telomeric of the major histocompatibility complex (MHC) that is identical-by-descent in 85% of patient chromosomes. Within this region, we have identified a gene related to the MHC class I family, termed HLA-H, containing two missense alterations. One of these is predicted to inactivate this class of proteins and was found homozygous in 83% of 178 patients. A role of this gene in haemochromatosis is supported by the frequency and nature of the major mutation and prior studies implicating MHC class I-like proteins in iron metabolism.

Ammonia and urea in corn silage-based complete mixed diets for dairy cows.

Source of supplemental N was evaluated in three corn silage-based complete mixed diets (CMD) fed to lactating dairy cows. Diets were formulated to be isonitrogenous and contained 60% corn silage and 40% concentrate on a dry matter basis. Diets were: CMD-A, ammoniated corn silage (ammonia provided 16% of total N) plus concentrate; CMD-U, untreated corn silage and concentrate (16% of total N from urea) and CMD-S, untreated corn silage plus concentrate with soybean meal. Ammoniation at 1.0% of dry weight increased crude protein content of silage from 8.5 to 12.7%. Daily means for cows fed CMD-A, CMD-U and CMD-S were: 24.2, 24.3 and 24.5 kg of fat-corrected milk; 3.17, 3.10 and 3.15% milk protein; 3.41, 3.67 and 3.63% milk fat and 3.02, 2.99 and 3.02 kg intake of total dry matter/100 kg body weight. Differences were not significant except for reduced milk fat percentage for cows fed the ammoniated corn silage diet. Both anhydrous ammonia and urea at 16% of total dietary N were found to be practical and economical substitutes for part of the supplemental soy protein. When compared to CMD with all soybean protein, greater savings in feed costs resulted from inclusion of ammoniated corn silage than with inclusion of urea.

Penicillanic acid derivatives in the canine prostate.

Distribution of ampicillin, amoxicillin, bacampicillin, mecillinam, pivmecillinam, carbenicillin, indanyl sodium was studied in the canine prostate, prostatic interstitial fluid, and prostatic secretion. All seven antibiotics were found in higher concentrations in the prostatic interstitial fluid than in the prostatic secretion. As expected for weak acids, drug concentrations in these fluids were always lower than the simultaneous serum concentrations. Tissue penetration was enhanced for the penicillin ester, pivmecillinam, as shown by its prostatic secretion/serum and tissue/serum ratios, which were higher than those of the other antibiotics, including the esters, bacampicillin, and carbenicillin indanyl sodium. This results may be due to pivmecillinam's long hydrolysis half-life. The concentrations for these penicillanic acid derivatives in prostatic interstitial fluid were above the minimal inhibitory concentrations for most of the commonly encountered gram-negative bacteria encountered in prostatitis. Therefore, these antibiotics should be effective in the treatment of bacterial prostatitis caused by susceptible organisms. Carbenicillin and carbenicillin indanyl sodium had the highest prostatic interstitial fluid/serum ratios of the compounds tested, and theoretically, therefore, they should be the most effective in the treatment of prostatitis. However, clinical trials should be carried out to confirm this.

Variables associated with peripartum traits in dairy cows. I. Effect of dietary forages and disorders on voluntary intake of feed, body weight and milk yield.

Daily voluntary intakes of feed by each of 89 Holstein cows were compared between day 220 of gestation and day 30 postpartum over a 21-month period. Diets designed to meet NRC requirements and which contained either chopped hay (29 cows), hay crop silage (HCS; 30 cows) or corn silage (CS; 30 cows) were compared prepartum (27 to 0 days), peripartum (1 day before to 3 days after calving) and postpartum (days 4 to 30 postpartum). Mixed rations, fed during lactation, were 60% forage and 40% concentrate dry matter (DM). Cow management was similar to commercial operations. The experimental hypothesis was that pre-disposition for partum and postpartum disorders (abnormal) could be related either to voluntary intake of different diets or to physical traits. Intakes (DM or estimated net energy) across diets decreased 30% between days 7 and 1 prepartum and averaged 18% and 20% lower peripartum and postpartum, respectively, in abnormal cows than in control cows. Seasonal effects on intakes were significant. In general, changes in body weight and condition and differences in udder edema and milk yield reflected intakes. The results support the original hypothesis.

Variables associated with peripartum traits in dairy cows. II. Interrelationships among disorders and their effects on intake of feed and on reproductive efficiency.

Daily individual voluntary intakes of dry matter (DM % of body weight) and estimated net energy (ENE, Mcal/100 kg) by 89 Holstein cows were compared between day 220 of gestation and day 30 postpartum over a 21-month period. The purpose was to compare effects of diet and health status (control vs. abnormal) on intakes of DM and ENE. The cows were fed either chopped hay, hay crop silage (HCS) or corn silage (CS). Compared to controls, voluntary intakes of DM and ENE were decreased (most to least) in cows with fat cow syndrome (FCS), parturient paresis (PP), mastitis (MST), retained fetal membranes-metritis (RFM-M), and displaced abomasum (DA) prepartum and FCS, DA, PP, RFM-M and MST peripartum. Cows fed hay had a lower incidence of RFM-M (28%) than cows fed HCS (57%) and CS (47%) as well as superior reproductive efficiency subsequently (89% conceived vs. 72% and 78%, respectively).