Bilary lipid metabolism in obesity. Effects of bile acid feeding before and during weight reduction.

Obese subjects are prone to supersaturated bile, which is maintained or increased during weight loss. In this report, two related studies were carried out on obese subjects to investigate effects of bile acid feeding on biliary lipid metabolism before and during weight reduction. In one study, chenodeoxycholic acid (CDCA), 750 mg/day, was given to 12 obese subjects during weight maintenance (1st mo) and during weight reduction (2nd mo). In the second study, effects of two bile acid preparations, CDCA and Bilron (containing mostly cholic acid and deoxycholic acid), randomly administered, were compared in another 12 obese subjects undergoing weight reduction. The results show that obese subjects had large pools of bile acids during weight maintenance which decreased on caloric restriction (1,000 kcal/day). CDCA increased pool size only modestly during weight maintenance, from 3,536 +/- 1,267 (SD) mg to 4,735 +/- 1,434 mg. Both CDCA and Bilron markedly reexpanded the contracted pool of bile acids in obese subjects on weight reduction. However, significantly reduced saturation of bile occurred only in those on CDCA and weight reductions, whereas supersaturation was unaltered when weight was maintained constant in these patients, or when Bilron was given. No significant side effects were noted during bile acid feeding for any of the subjects. Thus, CDCA given to obese subjects on weight reduction will reduce bile saturation and could protect against gallstones.     

New selective medium for the isolation of Neisseria gonorrhoeae.

GC-Lect, a new selective medium for the isolation of Neisseria gonorrhoeae which contains five antimicrobial agents, was evaluated with stock cultures and with 500 clinical specimens. With stock cultures, vancomycin-resistant Staphylococcus epidermidis that grew on modified Thayer-Martin medium (MTM) was inhibited on the new medium. Also, vancomycin-susceptible strains of N. gonorrhoeae were much less inhibited on the new medium than on Martin-Lewis agar or MTM. With oropharyngeal cultures of healthy volunteers, Capnocytophaga species were frequently isolated on MTM from two of three manufacturers but were completely inhibited on GC-Lect. In the clinical study, visible growth of N. gonorrhoeae occurred within 24 h in 72% of the positive cultures on GC-Lect, compared with only 52% on the reference medium. A total of 50 positive cultures were obtained with GC-Lect, compared with 49 obtained with MTM. The selectivity of GC-Lect was superior, with only 19 cultures producing growth of normal flora, compared with 78 cultures on MTM after 24 h of incubation. The selectivity was especially improved on GC-Lect with regard to yeasts (2 versus 30 cultures) and gram-positive cocci (5 versus 31 cultures).     

Synthesis and antimicrobial evaluation of 20-deoxo-20-(3,5-dimethylpiperidin-1-yl)desmycosin (tilmicosin, EL-870) and related cyclic amino derivatives

A series of 20-deoxo-20-cyclic (alkylamino) derivatives of tylosin, desmycosin, macrocin and lactenocin was prepared by reductive amination of the C-20 aldehyde group. The majority of the compounds were prepared using metal hydrides (sodium cyanoborohydride or sodium borohydride) as the reducing agents and a suitable cyclic alkylamine. Subsequently, a more convenient procedure was developed using formic acid as a reducing agent. The C-20 amino derivatives prepared from desmycosin exhibited good in vitro antimicrobial activity against Pasteurella haemolytica and Pasteurella multocida (MIC range of 0.78 approximately 6.25 micrograms/ml) as well as Mycoplasma species (MIC range of 0.39 approximately 6.25 micrograms/ml). Several derivatives showed excellent oral efficacy against infections caused by P. multocida in chicks. One of these derivatives, 20-deoxo-20-(3,5-dimethylpiperidin-1-yl)desmycosin (tilmicosin or EL-870) was selected for development as a therapeutic agent for pasteurellosis in calves and pigs.     

Physiologically based pharmacokinetic modeling of cyclotrimethylenetrinitramine in male rats

A physiologically based pharmacokinetic (PBPK) model for simulating the kinetics of cyclotrimethylene trinitramine (RDX) in male rats was developed. The model consisted of five compartments interconnected by systemic circulation. The tissue uptake of RDX was described as a perfusion‐limited process whereas hepatic clearance and gastrointestinal absorption were described as first‐order processes. The physiological parameters for the rat were obtained from the literature whereas the tissue : blood partition coefficients were estimated on the basis of the tissue and blood composition as well as the lipophilicity characteristics of RDX (logP = 0.87). The tissue : blood partition coefficients (brain, 1.4; muscle, 1; fat, 7.55; liver, 1.2) obtained with this algorithmic approach were used without any adjustment, since a focused in vitro study indicated that the relative concentration of RDX in whole blood and plasma is about 1 : 1. An initial estimate of metabolic clearance of RDX (2.2 h^?1 kg^?1) was obtained by fitting PBPK model simulations to the data on plasma kinetics in rats administered 5.5 mg kg^?1 i.v. The rat PBPK model without any further change in parameter values adequately simulated the blood kinetic data for RDX at much lower doses (0.77 and 1.04 mg ^?1 i.v.), collected in this study. The same model, with the incorporation of a first order oral absorption rate constant (K_a 0.75 h^?1), reproduced the blood kinetics of RDX in rats receiving a single gavage dose of 1.53 or 2.02 mg kg^?1. Additionally, the model simulated the plasma and blood kinetics of orally administered RDX at a higher dose (100 mg kg^?1) or lower doses (0.2 or 1.24 mg kg^?1) in male rats. Overall, the rat PBPK model for RDX with its parameters adequately simulates the blood and plasma kinetic data, obtained following i.v. doses ranging from 0.77 to 5.5 mg kg^?1 as well as oral doses ranging from 0.2 to 100 mg kg^?1. Published in 2009 by John Wiley & Sons, Ltd.     

Increased hematopoietic progenitor cell maintenance in long-term bone marrow cultures containing minimal numbers of contaminating breast cancer cells

The maintenance of hematopoietic progenitor cells as assayedin the mixed colony (CFU-GEMM) assay in humanlong-term bone marrow cultures was compared between normalallogeneic marrow transplantation donor collections and those fromcandidates for high-dose therapy and autologous bone marrowtransplantation (ABMT). To be eligible for ABMT, patientswere required to have a histologically normal appearingbone marrow and therefore any tumor contamination wasat minimal levels and detectable only after evaluationof the cultured harvests. Marrow from 15 normaldonors, 36 patients with breast cancer, and 30patients with Hodgkin's disease was evaluated. The numberof mononuclear cells placed in culture was standardized.In all groups, significantly more progenitor cells wererecovered at 4–6 weeks of culture than at12–14 weeks. At 4–6 and 12–14 weeks, therewere no significant differences in the number ofprogenitor cells recovered from the cultures of normaldonors and tumor negative cultures of breast canceror Hodgkin's disease patients. However, following 4–6 and12–14 weeks of culture, progenitor cell numbers ofcultures which contained breast cancer cells were significantlyhigher than the pooled values for cultures fromthe concurrent normal controls, and those from breastcancer and Hodgkin's disease patients with tumor negativecultures. These results suggest that minimal breast cancercell contamination of the bone marrow can influencethe production of marrow progenitor cells. Exposure toprior chemotherapy or radiation therapy does not appearto be the cause of this effect. Themost likely mechanism is the local production ofcytokines by the tumor cells, although a processinvolving direct adhesive contact of the tumor cellswith hematopoietic cells, which is sometimes observed insemisolid cultures, cannot be excluded.     

Developmental toxicity of thiodiglycol in Sprague-Dawley rats

Thiodiglycol (TG), a hydrolysis product of sulfur mustard (HD), is a potential contaminant of soil and water at certain military sites. To establish developmental toxicity criteria for TG, an oral developmental toxicity study was conducted in Sprague-Dawley rats. Neat thiodiglycol (99.9 %) was administered orally to mated female rats from gestation days (GDs) 5 through 19. The day of positive mating was considered day 0. A pilot study was conducted with TG at dose levels 250, 500, 1,000, 2,000, or 5,000 mg/kg to select suitable doses for the main study. In the main study, three groups of rats (25/group) received TG by gavage at dose levels of 430, 1,290, or 3,870 mg/kg/day. A fourth group served as a sham control. On day 20 of gestation, all females were euthanized and a cesarean section performed. Litters were examined for soft tissue and skeletal alterations. Maternal toxicity was limited to dams receiving TG at 3,870 mg/kg/day. At this dose, body weights and food consumption were reduced during certain periods of gestation. Fetuses derived from those dams exhibited a nonstatistically significant increased incidence of variations when compared to controls. Fetal body weights in the 3,870 mg/kg/day group were significantly lower than controls. There was no increased incidence of anomalies when thiodiglycol-treated fetuses were compared to controls. It was concluded that TG did not produce terata. Developmental toxicity (decreased fetal weights and associated delays in development) occurred only at the maternally toxic dose of 3,870 mg/kg. It appears that 1,290 mg/kg/day could be considered no observed adverse effect level (NOAEL) for oral developmental toxicity. The lowest observed adverse effect level (LOAEL) was 3,870 mg/kg for maternal toxicity.     

Intrarectal amifostine during external beam radiation therapy for prostate cancer produces significant improvements in Quality of Life measured by EPIC score

PURPOSE: To test whether intrarectal amifostine limits symptoms of radiation proctitis, measured by using the Radiation Therapy Oncology Group (RTOG) gastrointestinal (GI) toxicity score and the Expanded Prostate Cancer Index Composite (EPIC) score. METHODS AND MATERIALS: Patients with localized prostate cancer received amifostine as a rectal suspension 30-45 minutes before daily three-dimensional conformal radiation therapy. The first 18 patients received 1 g of amifostine, and the next 12 patients received 2 g. Toxicity was assessed at baseline, during treatment, and at follow-up visits by using RTOG grading and the EPIC Quality of Life (QoL) 50-item questionnaire. The Bowel Function subset of the bowel domain (EPIC-BF), which targets symptom severity, and the Bowel Bother subset of the bowel domain (EPIC-BB), which assesses QoL, were evaluated and compared with the RTOG GI toxicity score. RESULTS: Median follow-up was 30 months (range, 18-36 months). Overall, EPIC-BF and EPIC-BB scores both tracked closely with the RTOG GI toxicity score. Seven weeks after the start of radiation therapy, the incidence of RTOG Grade 2 toxicity was 33% in the 1-g group (6/18 patients) compared with 0% (0/12 patients) in the 2-g group and tended toward statistical significance (p = 0.06). A significant difference between amifostine groups was observed using the EPIC-BF score at 7 weeks (p = 0.04). A difference in EPIC-BB scores between dose groups was evident at 7 weeks (p = 0.07) and was significant at 12 months (p = 0.04). CONCLUSIONS: Higher doses of amifostine produced significant improvements in acute and late bowel QoL (up to 1 year after therapy), measured using the EPIC score.