Polymers with cavities tuned for fast selective transport of small molecules and ions

Within a polymer film, free-volume elements such as pores and channels typically have a wide range of sizes and topologies. This broad range of free-volume element sizes compromises a polymer's ability to perform molecular separations. We demonstrated free-volume structures in dense vitreous polymers that enable outstanding molecular and ionic transport and separation performance that surpasses the limits of conventional polymers. The unusual microstructure in these materials can be systematically tailored by thermally driven segment rearrangement. Free-volume topologies can be tailored by controlling the degree of rearrangement, flexibility of the original chain, and judicious inclusion of small templating molecules. This rational tailoring of free-volume element architecture provides a route for preparing high-performance polymers for molecular-scale separations.     

Chitin biosynthesis inhibition and fungicidal effect of thiosemicarbazones of 2-formyl- and 2-acetylpyridine,their hydrogenated derivatives and copper complexes thereof

Several thiosemicarbazones of 2-formyl- and 2-acetylpyridine dialkylated on N⁴ and non-alkylated on N² were found to be broad-spectrum protectant fungicides with activity particularly against oomycetes. The effect of some of the compounds on chitin biosynthesis was studied, but the low inhibitory activity observed combined with the fungicidal activity spectrum—particularly the high activity against oomycetes—excludes this as their main mode of action. Attempts at enhancing the systemic properties of the compounds by chemical modifications failed.     

Exploring passive transfer in muskoxen (Ovibos moschatus).

Poor calf production and ill thrift in 3-4 mo olds are common limiting problems in raising and maintaining captive muskoxen (Ovibos moschatus). Acute onset of a rapidly progressing enteritis and septicemia in neonatal calves (2-7 days of age) caused by Escherichia coli not normally considered pathogenic in domestic animals is a serious problem in many captive muskoxen facilities. Serum immunoglobulin G (IgG) levels, total protein, albumin, and globulin levels in captive periparturient muskox females and their neonatal calves were compared with levels found in other species in which these parameters have been well described. Results showed that all females in the study had IgG present in their serum (mean = 1,232.14 mg/dl, SD = 178.34 mg/dl, as measured via radial immunodiffusion). Calves were probably born agammaglobulinemic or hypogammaglobulinemic. IgG levels quickly rose in calves after initial colostrum intake to levels similar to those seen in other domestic ruminants. Our results suggest that passive transfer of immunity in muskoxen is similar to what is reported in domestic livestock and that reference ranges from domestic cattle may be used to assist interpretation of serum IgG levels in muskoxen. In addition, the positive relationship between serum protein and globulin levels with serum IgG levels is similar to that reported for Holstein cattle and thus provides a useful indicator of passive transfer in muskoxen.     

Evaluation of the antibacterial activity of skin mucus of three carp species

International Aquatic Research - Studies were conducted to evaluate the antimicrobial potency of skin mucus collected from three carp species; Hypophthalmichthys nobilis, Ctenopharyngodon idella,...     

The Activity and Localization of 3β-hydroxysteroid Dehydrogenase/Δ5-Δ4 Isomerase and Release of Androstenedione and Progesterone by Uterine Tissues During Early Pregnancy and the Estrous Cycle in Pigs

Steroid hormones are produced by the porcine uterus. We hypothesized that the uterus in pigs possesses active 3β-hydroxysteroid dehydrogenase/Δ⁵-Δ⁴ isomerase (3β-HSD) responsible for progesterone and androstenedione production, that uterine steroids may supplement the amount of steroid hormones produced by embryos and corpus luteum and that these steroids are necessary for maintenance of pregnancy. In this study, we examined 1) endometrial and myometrial expression of 3β-HSD mRNA, 2) uterine 3β-HSD protein activity and 3) in vitro production of A₄ and P₄ by uterine slices harvested from pigs on days 10 to 11, 12 to 13 and 15 to 16 of pregnancy and the estrous cycle. The expression of 3β-HSD and the presence and activity of 3β-HSD protein were different in the endometrium and the myometrium during the examined periods of pregnancy and the estrous cycle. Production of A₄ by the endometrium and myometrium was highest on days 12 to 13 of pregnancy and the estrous cycle. Endometrial secretion of P₄ did not differ in the course of early pregnancy and on the respective days of the estrous cycle. The gravid myometrium was the highest source of P₄ in pregnant pigs on days 12 to 13. The release of P₄ by the cyclic myometrium rose during the examined days of the estrous cycle. The steroidogenic activity of the uterus, as described in this study, may support early pregnancy or the luteal phase of the estrous cycle in pigs.     

Persistence of Mycoplasma synoviae in hens after two enrofloxacin treatments and detection of mutations in the parC gene

The ability of Mycoplasma synoviae, an avian pathogen, to persist despite fluoroquinolone treatments was investigated in hens. Groups of Mycoplasma-free hens were experimentally infected with the M. synoviae 317 strain and treated twice with enrofloxacin at the therapeutic dose. The results show that the two treatments did not have any influence on this strain of M. synoviae recovery from tracheal swabs. Mycoplasmas were isolated from tracheal swab cultures, but not from inner organs such as the liver or spleen, suggesting that this strain of M. synoviae was not able to cross the mucosal barrier to disseminate throughout the host. A significant increase of the resistance level to enrofloxacin of five re-isolated mycoplasma clones, was observed after the second treatment. This increase was associated in two clones to a Ser81-->Pro substitution, found in the ParC quinolone-resistance determining region (QRDR) of DNA topoisomerase IV. This is the first time that a mutation in a gene coding for topoisomerase IV is described in M. synoviae after in vivo enrofloxacin treatments in experimentally infected hens.     

Blood smear from a pregnant cat that died shortly after partial abortion

A 1-year-old, 5- to 6-week pregnant cat was presented with a history of aborting 3 kittens the previous night. During the examination, the cat began to seizure and died. At necropsy, formalin-fixed tissues and blood smears prepared from an EDTA blood sample collected via cardiac puncture were submitted to a diagnostic laboratory. Examination of the blood smears revealed numerous large (15-75 microm) clumped macrophages containing dark blue intracytoplasmic organisms consistent with Cytauxzoon merozoites. Scattered erythrophagocytic macrophages were also observed. Within several erythrocytes, 1-2 small, round, ring-like piroplasms consistent with Cytauxzoon were observed. Histologic examination revealed numerous large, schizont-laden macrophages filling the blood vessels of multiple organs. The cytologic and histologic findings were diagnostic for Cytaxuzoon felis infection. This case was of particular interest because of the unusually large number of organism-laden macrophages in the cardiac blood sample, an uncommon finding in peripheral blood. Although the cat was presented for complications of abortion, it remains uncertain whether C felis organisms crossed the placenta and infected the fetuses or lead to the abortions.     

A multi-institutional epidemiologic study evaluating environmental risk factors for feline oral squamous cell carcinoma

Feline oral squamous cell carcinoma (FOSCC) is an aggressive cancer in domestic cats that has no effective treatment option when advanced. Preventative or early diagnostic measures are thus crucial. FOSCC is also a model for human head and neck SCC (HNSCC); strong risk factors in HNSCC include exposure to alcohol, tobacco, areca nut, and high-risk human papillomavirus. Previous studies have identified flea collar and tobacco smoke exposure, feeding canned tuna, canned cat food and cat foods with chemical additives, living in a rural environment, and having outdoor access as risk factors for FOSCC but there was no overlap in the risk factors between studies. In our study, risks for FOSCC were evaluated in an online epidemiologic survey study in 67 cats with FOSCC and 129 control cats. Clumping clay cat litter and flea collar use were significant risk factors for FOSCC on multiple logistic regression with odds ratios of 1.66 (95% CI 1.20–2.30) and 4.48 (95% CI 1.46–13.75) respectively. Crystalline silica is a carcinogen that may be present in all clay cat litters and tetrachlorvinphos is a carcinogen that is present in the most commonly used flea collars in our study. We recommend further investigation into the association between FOSCC and clay-based litter and/or flea collars containing tetrachlorvinphos.     

Prevalence,quantitative load and genetic diversity of Campylobacter spp. in dairy cattle herds in Lithuania

Background

Campylobacteriosis is a zoonotic disease, and animals such as poultry, pigs and cattle may act as reservoirs for Campylobacter spp. Cattle shed Campylobacter spp. into the environment and they can act as a reservoir for human infection directly via contact with cattle or their faeces or indirectly by consumption of contaminated food. The aim of this study was to determine the prevalence, the quantitative load and the genetic strain diversity of Campylobacter spp. in dairy cattle of different age groups.

Results

Faecal samples of 200 dairy cattle from three farms in the central part of Lithuania were collected and examined for Campylobacter. Cattle herds of all three farms were Campylobacter spp. positive, with a prevalence ranging from 75% (farm I), 77.5% (farm II) to 83.3% (farm III). Overall, the highest prevalence was detected in calves (86.5%) and heifers (86.2%). In contrast, the lowest Campylobacter prevalence was detectable in dairy cows (60.6%). C. jejuni, C. coli, C. lari and C. fetus subsp. fetus were identified in faecal samples of dairy cattle. C. upsaliensis was not detectable in any sample. The high counts of Campylobacter spp. were observed in faecal material of dairy cattle (average 4.5 log₁₀ cfu/g). The highest numbers of Campylobacter spp. were found in faecal samples from calves (average 5.3 log₁₀ cfu/g), whereas, faecal samples from cows harboured the lowest number of Campylobacter spp. (average 3.7 log₁₀ cfu/g). Genotyping by flaA PCR-RFLP analysis of selected C. jejuni isolates showed that some genotypes were present in all farms and all age groups. However, farm or age specific genotypes were also identified.

Conclusions

Future studies are needed to investigate risk factors related to the degree of colonisation in cattle. Based on that, possible measures to reduce the colonisation and subsequent shedding of Campylobacter in cattle could be established. It is important to further investigate the epidemiology of Campylobacter in the cattle population in order to assess associated risks to public health.