Longitudinal evaluation of fentanyl concentrations in equine plasma and synovial fluid following application of transdermal fentanyl patches over one carpal joint.

OBJECTIVE: To determine if transdermally delivered fentanyl can achieve greater concentrations of fentanyl in synovial fluid when applied over a synovial structure. STUDY DESIGN: Randomized, experimental study. ANIMALS: Six healthy adult horses. METHODS: Each horse had two 100 µg/h fentanyl matrix patches applied on the dorsal aspect of one, randomly assigned, carpometacarpal joint (CMCJ) for 48 h. Whole blood and bilateral synovial samples from the intercarpal joint were obtained at 0, 2, 6, 12, 24, 36 and 48 h. Fentanyl concentrations were measured with liquid chromatography-mass spectrometry. RESULTS: All subjects achieved detectable concentrations of fentanyl in both plasma and synovial fluid. Time to peak synovial and plasma concentration was 12 h. At 6 h, the synovial concentration in the untreated carpus (0.104 ng/mL ± 0.106) was lower than plasma fentanyl concentrations 0.31 ± 0.27 (p = .036). At 12 h, both treated (0.55 ng/mL ± 0.3) and untreated (0.53 ng/mL ± 0.28) synovial fluid fentanyl concentrations were lower than plasma (0.87 ng/mL ± 0.48) concentrations (p < .001 and p = .001, respectively). Synovial concentrations of fentanyl did not differ between treated and untreated joints (p > 0.608 for all time points). CONCLUSION: Application of fentanyl matrix patches directly over the CMCJ did not result in increased fentanyl concentrations in the synovial fluid of the treated intercarpal joint in normal horses. CLINICAL SIGNIFICANCE: There is likely no analgesic advantage to placing fentanyl patches directly over the affected joint, as it did not result in increased synovial concentrations at the tested site.

Cryptic genetic diversity and associated ecological differences of Anastatus orientalis, an egg parasitoid of the spotted lanternfly.

Anastatus orientalis, native to northern China, is an egg parasitoid wasp of the spotted lanternfly (Lycorma delicatula) and is being tested as a potential biological control agent for invasive L. delicatula in the United States. As a component of these evaluations, live A. orientalis collected from Beijing and Yantai in China were reared in containment in the U.S. These specimens showed different responses in diapause behaviors to rearing conditions used previously by other researchers. To understand the primary mechanism potentially driving discrepancies in important life history traits, we used molecular tools to examine the genetic composition of A. orientalis from China and from South Korea, where the parasitoid has been introduced to aid in the population management of invasive L. delicatula. Molecular analysis of mitochondrial DNA recovered six haplotype groups, which exhibit biased frequency of abundance between collection sites. Some haplotypes are widespread, and others only occur in certain locations. No apparent pattern is observed between wasps collected from different years or emergence seasons. Uncorrected genetic distances between haplotype groups range from 0.44% to 1.44% after controlling for within-group variation. Genetic variance of A. orientalis is characterized by high levels of local diversity that contrasts with a lack of a broad-scale population structure. The introduced Korean population exhibits lower genetic diversity compared to native populations. Additionally, we created iso-female lines for major haplotype groups through laboratory rearing. Differences in diapause behavior were correlated with mitochondrial haplotype. Our results indicate that the observed life history traits in A. orientalis have a genetic base.

Beetle Diversity Across Micro-habitats on Lizard Island Group (Great Barrier Reef, Australia).

The beetles (Coleoptera) of Lizard Island group, a complex of small granitic islands on the Great Barrier Reef, have never been systematically assessed. In April 2019, we conducted the first survey of the island group across different micro-habitats. We specifically aimed to determine which beetle families are the most diverse, and how beetle diversity varies across the island group. We sampled several sites on seven large collection areas using a variety of methods: pitfall traps, beating sheet, sifting leaf litter, and active night and day collection. Our sampling yielded 108 beetle morphospecies representing at least 21 families. The most diverse families on Lizard Island group were Curculionidae, Carabidae, Scarabaeidae, Tenebrionidae, and Cerambycidae, in general accordance with global patterns in Coleoptera diversity. The families Chrysomelidae, Staphylinidae, and Buprestidae were found to be proportionally less diverse on the island group than on mainland Australia, though Australia as a whole is of limited value as a reference. Beetle diversity varied across both large-scale collection areas and small-scale collection sites on Lizard Island group. As expected, greater habitat complexity and vegetation diversity corresponded with greater beetle diversity, though these patterns might be biased due to the temporal and spatial limits of our sampling. We hope this preliminary survey will facilitate further research on Lizard Island group, taking advantage of the research facilities on the island and the possibility of establishing long-term studies.

Vitamin E but not St. John's wort mitigates leukopenia caused by cancer chemotherapy in rats.

Dietary supplements are used by most patients with cancer. As nutraceuticals can interact with many drugs, this study investigated the effect of herbal remedies and vitamins on the toxicity of representative cancer chemotherapeutic agents. Fisher 344 rats were fed a standard cereal-based diet or the same diet with additional vitamin E in low (50 mg/kg) or high (750 mg/kg) concentrations, or with added St. John's wort (400 mg/kg). The LD50 was determined after the administration of chemotherapy drugs. Neither low or high vitamin E supplements nor St. John's wort significantly changed the LD50 for doxorubicin, docetaxel, or cyclophosphamide. The nadir white blood cell (WBC) count was significantly higher (P = 0.004) after docetaxel in rats supplemented with low-dose vitamin E, but the drop in WBC count from initial to nadir levels (Nfall) was greater in rats fed a diet containing high vitamin E supplementation (P = 0.04). Similarly, the Nfall was greater in the standard and high vitamin E dietary groups than in the low vitamin E group after cyclophosphamide (P = 0.03). No effect of vitamin E or St. John's wort supplementation occurred on doxorubicin pharmacokinetics. Neither vitamin E nor St. John's wort had an important effect on the mitochondrial deoxyribonucleic acid (DNA) damage caused by either doxorubicin or docetaxel. These data suggest that the leucopenia caused by some chemotherapeutic agents can be modified by dietary supplementation with vitamin E, but the effect seems to be dose-dependent. St. John's wort had neither a beneficial nor a detrimental effect on chemotherapy-induced toxicity.

Analytical and pharmacokinetic studies with 5-chloro-2'-deoxycytidine.

5-Chloro-2'-deoxycytidine (NSC 371331, CDC) is in development as a possible radiosensitizing agent for cancer treatment. Previous studies have been done to demonstrate the in vivo efficacy of CDC with various modulators of its metabolism. This paper describes our preclinical studies to determine the pharmacokinetic properties of CDC and the disposition of the drug, both alone and in the presence of the metabolic modulator tetrahydrouridine (THU), a cytidine deaminase inhibitor. Detection of the drug in biological fluids was performed by HPLC analysis using a C-18 column, gradient elution with solvents composed of aqueous trifluoroacetic acid and acetonitrile, and ultraviolet absorbance at 290 nm. Samples were processed by treatment with ammonium sulfate prior to injection into the HPLC system. CDC was stable in aqueous solution and in mouse plasma. High doses of CDC (100mg/kg) were given i.v. or i.p. to mice for the determination of CDC plasma half-life (10 min). CDC was not detectable in plasma after oral administration. It was converted rapidly to 5-chloro-2'-deoxyuridine (CDU) by cytidine deaminase, and CDU was readily discernable in plasma and urine samples collected after i.v. and i.p. administration of CDC. When CDC in doses ranging from 5 to 100mg/kg was given with 100mg/kg of THU, increased plasma levels of CDC were seen. CDC was eliminated through the kidneys, as well as by enzymatic deamination, and did not bind to plasma proteins. The initial steps of the CDC metabolic pathway were determined in vitro with isolated enzymes. Cytidine deaminase from mouse kidney converted CDC into CDU; thymidine phosphorylase converted CDU into 5-chlorouracil (5-CU). The conclusions of these studies are: (a) CDC is a drug with a short half-life and (b) it is excreted through the kidney, mainly in metabolite form. Administration of THU substantially increased the concentrations of CDC in mouse plasma, supporting proposals that the combination of THU with CDC should be evaluated in clinical trials.

Diet modulates the toxicity of cancer chemotherapy in rats.

The effects of diet and folate status on cyclophosphamide or 5-fluorouracil toxicity were studied in Fischer 344 rats maintained on either a cereal-based diet or a purified diet (AIN-93G). The rats fed the purified diet were divided into 3 groups: folate deficient (no dietary folic acid), folate replete (2 mg folic acid/kg diet), and high folate (2 mg folic acid/kg diet plus 50 mg/kg body weight folic acid intraperitoneally daily). The LD50 for cyclophosphamide was significantly higher for the cereal diet than for the purified diets, but there was no difference among the purified diets. Deaths were predicted by dose, diet, white blood cell count, and BUN on Day 4 after treatment. In the saline-treated rats fed the purified diet, hepatic total glutathione levels increased in the following order: folate deficient < folate replete < high folate. There was no significant difference in aldehyde dehydogenase activities or of microsomal P450 levels in livers from rats on the different diets. In the rats treated with 5-fluorouracil, the high folate rats developed more severe anemia, azotemia, and leukopenia than the other groups. Weight, white blood cell count, hematocrit, and BUN were important predictors of death. The kidneys from rats fed the cereal-based diet were histologically normal, but rats ingesting the purified diet had increasing renal pathology that correlated with folate intake. These results indicate that diet has an important influence on the toxicity of cyclophosphamide and 5-fluorouracil and that folate status modulates hepatic glutathione levels, which is a major cellular defense against oxidant and alkylating agent damage.