Autosomal recessive hypotrichosis with loose anagen hairs associated with TKFC mutations.

BACKGROUND: Loose anagen hair is a rare form of impaired hair anchorage in which anagen hairs that lack inner and outer root sheaths can be gently and painlessly plucked from the scalp. This condition usually occurs in children and is often self-limiting. A genetic basis for the disorder has been suggested but not proven. A better understanding the aetiology of loose anagen hair may improve prevention and treatment strategies. OBJECTIVES: To identify a possible genetic basis of loose anagen hair using next-generation DNA sequencing and functional analysis of variants identified. METHODS: In this case study, whole-exome sequencing analysis of a pedigree with one affected individual with features of loose anagen hair was performed. RESULTS: The patient was found to be compound heterozygous for two single-nucleotide substitutions in TKFC resulting in the following missense mutations: c.574G> C (p.Gly192Arg) and c.682C> T (p.Arg228Trp). Structural analysis of human TKFC showed that both mutations are located near the active site cavity. Kinetic assays of recombinant proteins bearing either of these amino acid substitutions showed almost no dihydroxyacetone kinase or D-glyceraldehyde kinase activity, and FMN cyclase activity reduced to just 10% of wildtype catalytic activity. CONCLUSIONS: TKFC missense mutations may predispose to the development of loose anagen hairs. Identification of this new biochemical pathobiology expands the metabolic and genetic basis of hypotrichosis.

Understanding the structural details of APOBEC3-DNA interactions using graph-based representations.

Human APOBEC3 (A3; apolipoprotein B mRNA editing catalytic polypeptide-like 3) is a family of seven enzymes involved in generating mutations in nascent reverse transcripts of many retroviruses, as well as the human genome in a range of cancer types. The structural details of the interaction between A3 proteins and DNA molecules are only available for a few family members. Here we use homology modelling techniques to address the difference in structural coverage of human A3 enzymes interacting with different DNA substrates. A3-DNA interfaces are represented as residue networks ("graphs"), based on which features at these interfaces are compared and quantified. We demonstrate that graph-based representations are effective in highlighting structural features of A3-DNA interfaces. By large-scale in silico mutagenesis of the bound DNA chain, we predicted the preference of substrate DNA sequence for multiple A3 domains. These data suggested that computational modelling approaches could contribute in the exploration of the structural basis for sequence specificity in A3 substrate selection, and demonstrated the utility of graph-based approaches in evaluating a large number of structural models generated in silico.

Investigation of the relationship between low environmental exposure to metals and bone mineral density, bone resorption and renal function.

Environmental exposure to metals has been linked to adverse health outcomes. Exposure to cadmium has been associated with decreased bone density, an increased risk of osteoporotic fracture and possible renal dysfunction. Older women are a group at risk of renal and bone density impacts and exposure to metals may be an important risk factor for these health outcomes. This study was a cross sectional study of 77 women aged 50 years and above examining the relationship between metals exposure and renal and bone health. Urinary and blood metals concentrations, plasma creatinine, iron, ferritin and transferrin were measured in these subjects. Bone biomarkers assessed included the pyridinium crosslinks, pyridinoline and deoxypyridinoline measured by ELISA. Renal function was assessed using eGFR and KIM-1. Whole body, hip and lumbar spine bone mineral density was assessed using DEXA. Blood and urinary metals concentrations were generally low in the subjects, with a median urinary cadmium concentration of 0.26 µg/g creatinine (range <0.065-1.03 µg/g). Urinary cadmium was found to be a significant predictor of bone mineral density at whole body, lumber spine, total hip and femoral neck, with increasing urinary Cd concentrations associated with decreased bone density. Urinary cadmium and aluminium concentrations were positively correlated with bone resorption whilst blood zinc and mercury concentrations were negatively correlated. Urinary aluminium was positively correlated with KIM-1 concentrations, a marker of early kidney damage, however blood zinc concentrations were significantly negatively correlated with this biomarker. This study provides additional support for low cadmium exposure being of concern for the health of older women. Further investigation into the role of exposure to other metals on bone and renal health is warranted.

Effect of preweaned dairy calf housing system on antimicrobial resistance in commensal Escherichia coli.

Group housing of preweaned dairy calves is a growing practice in the United States. The objective of this practice is to increase the average daily gain of calves in a healthy and humane environment while reducing labor requirements. However, feeding protocols, commingling of calves, and occurrence of disease in different calf-housing systems may affect the prevalence of antimicrobial drug-resistant bacteria. This study evaluated the effect of a group pen-housing system and individual pen-housing system on antimicrobial resistance trends in fecal Escherichia coli of preweaned dairy calves and on the prevalence of environmental Salmonella. Twelve farms from central New York participated in the study: 6 farms using an individual pen-housing system (IP), and 6 farms using a group pen-housing system (GP). A maximum of 3 fecal E. coli isolates per calf was tested for susceptibility to 12 antimicrobial drugs using a Kirby-Bauer disk diffusion assay. Calves in GP had a significantly higher proportion of E. coli resistant to ciprofloxacin and nalidixic acid, whereas calves in IP had a significantly higher proportion of E. coli resistant to ampicillin, ceftiofur, gentamycin, streptomycin, and tetracycline. Calf-housing system had an effect on resistance to individual antimicrobial drugs in E. coli, but no clear-cut advantage to either system was noted with regard to overall resistance frequency. No outstanding difference in the richness and diversity of resistant phenotypes was observed between the 2 calf-housing systems.

Effect of on-farm use of antimicrobial drugs on resistance in fecal Escherichia coli of preweaned dairy calves.

Respiratory disease and diarrhea are the 2 most common diseases that result in the use of antimicrobial drugs in preweaned calves. Because the use of drugs in food animals, including dairy calves, has the potential for generating cross-resistance to drugs used in human medicine, it is vital to propose farm practices that foster the judicious use of antimicrobials while assuring animal health and productivity. The objective of this study was to use dairy farm calf treatment records to identify antimicrobial drug treatments in calves and to evaluate their effects on the prevalence of antimicrobial-resistant Escherichia coli from rectal swabs of preweaned dairy calves. Eight farms from central New York participated in the study, 3 farms using individual pen housing management and 5 farms using group pen housing management. Eligible study farms could not add antimicrobial drugs to the milk fed to preweaned calves and were required to have farm records documenting antimicrobial drug treatment of calves from birth to weaning. Three fecal E. coli isolates per calf were tested for susceptibility to 12 antimicrobial drugs using a Kirby-Bauer disk diffusion assay. A total of 473 calves were sampled, from which 1,423 commensal E. coli isolates were tested. Of the 9 antimicrobial drugs used on study farms, only enrofloxacin was significantly associated with reduced antimicrobial susceptibility of E. coli isolates, although treatment with ceftiofur was associated with reduced susceptibility to ceftriaxone. The median numbers of days from treatment with ceftiofur and enrofloxacin to rectal swab sampling of calves were 16 d (range: 1-39) and 12 d (range: 6-44), respectively. At the isolate level, treatment with enrofloxacin resulted in odds ratios of 2 [95% confidence interval (CI): 1-4] and 3 (95% CI: 2-6), respectively, for isolation of nonsusceptible E. coli to nalidixic acid and ciprofloxacin compared with calves not treated with enrofloxacin. Treatment with ceftiofur resulted in an odds ratio of 3 (95% CI: 0.9-12) for isolation of nonsusceptible E. coli to ceftriaxone compared with calves not treated with ceftiofur. Treatment with enrofloxacin resulted in selection of isolates that presented phenotypic resistance to both ciprofloxacin and ceftriaxone. Treatment with ceftiofur resulted in a higher prevalence of isolates resistant to ≥3 antimicrobial drugs (97%) compared with no treatment with ceftiofur (73%). These findings reinforce the necessity for continued implementation of practices at the dairy farm that support the sustainable and judicious use of antimicrobial drugs in dairy calves.

Equilibrium studies for the sorption of lead from effluents using chitosan.

The sorption of lead ions from aqueous solution onto chitosan has been studied. Equilibrium studies have been carried out to determine the capacity of chitosan for lead ions. The effects of solution pH and chitosan particle size on the sorption capacity have been studied.The experimental data were analyzed using three equilibrium isotherm correlations, namely, Langmuir, Freundlich and Redlich-Peterson equations. The linear correlation coefficients were determined for each isotherm and the Freundlich provided the best fit. In addition, error functions have been used to determine the alternative single component equilibrium isotherm parameters by non-linear regression due to the inherent bias in using the correlation coefficient from the linearization. This technique enables the "best fit" isotherm parameters to be used in the equilibrium equations for the sorption of lead ions on chitosan within the limits and assumptions of the various error analysis methods.

A field study conducted at Kidston Gold Mine, to evaluate the impact of arsenic and zinc from mine tailing to grazing cattle.

The grazing trial at Kidston Gold Mine, North Queensland, was aimed specifically to assess the uptake of metals from the tailing and the potential for unacceptable contamination of saleable meat. Further aims included estimating metal dose rates and identifying potential exposure pathways including plant uptake of heavy metals, mine tailings adhered to plants and direct ingestion of mine tailing. It was found that of the 11 metals analysed (As, Zn, Co, Cd, Cr, Sn, Pb, Sb, Hg, Se and Ni) in the animal's liver, muscle and blood during the 8-month trial period, only accumulation of arsenic and zinc occurred. A risk assessment including these two metals was conducted to determine the potential for chronic metal toxicity and long-term contamination, using the estimates of metal dose rate. It was concluded that no toxicity or long-term contamination in cattle was likely at this site. Management procedures were therefore not required at this site; however, the results highlight percent ground cover and standing dry matter (DM) as important factors in decreasing metal exposure from direct ingestion of tailings and dust adhered to plants.

Porphyrins as early biomarkers for arsenic exposure in animals and humans.

We studied the effect of arsenic exposure on the haem biosynthetic pathway in the rat and humans. Significant increases in protoporphyrin IX, coproporphyrin III, coproporphyrin I were observed in the blood, liver and kidney, and in the urine of rats after a single dose of arsenic. The level of increase was dependent on the arsenic species present. Most of porphyrin concentrations in the tissues increased within 24 hr and urinary excretion elevated within 48 hr. In the human study, we collected urine samples from 113 people who live in Xing Ren of Guizhou Province, a coal-borne arsenicosis endemic area in southwest of PR China and from 30 people who live in Xing Yi (about 80 km southwest of Xing Ren) where arsenicosis is not prevalent. We analyzed the urinary porphyrins using HPLC. Results indicate that all urinary porphyrins were higher in the arsenic exposed group than those in the control group. Women, children and older age people spend much of their time indoors, they had greater increases of urinary arsenic and porphyrins. They were the higher risk groups among the study subjects. A positive correlation between the urinary arsenic levels and porphyrin concentrations demonstrated the effect of arsenic on haem biosynthesis. Significant alteration in the porphyrin excretion profiles of the younger age (<20 y) arsenic exposed group suggested that porphyrins could be used as early warning biomarkers for chronic exposure to arsenic.

Equilibrium studies of the sorption of Cu(II) ions onto chitosan.

Chitosan is a polymer that can be obtained from the shells of seafood such as prawns, crabs, and lobsters. Chitosan has free amino groups, which can attract metal ions, and has been used as an adsorbent for the removal of metal ions from effluents. In this research, the sorption of copper ions from solution onto chitosan at two pHs has been investigated. DSC, TGA, surface area, SEM, and NMR studies have been used to report the pure physical states of chitosan and the chitosan-copper complex. The experimental isotherm data were analyzed using the Langmuir, Freundlich, and Redlich-Peterson equations. Correlation coefficients were determined for each isotherm analysis. Error functions have been used to determine the alternative single component parameters by nonlinear regression due to the inherent bias in using the correlation coefficient resulting from linearization. The error function method provided the best parameters for the isotherm equations in this system and is demonstrated for error comparison purposes.

A case of severe actinic prurigo successfully treated with thalidomide.

Actinic prurigo is an uncommon and usually persistent idiopathic photodermatosis with typical human leukocyte antigen (HLA) associations (HLA-DR4, particularly subtypes DRB1*0407 and DRB1*0401). Although its mechanism of action is not clearly understood, thalidomide has been shown to be particularly efficacious in treating actinic prurigo, among other conditions. A 31-year-old Australian woman who had suffered actinic prurigo for most of her life was treated with two courses of thalidomide (50-100 mg nocte) over consecutive summers. Remission was observed after cessation of the second course of thalidomide and had continued 4 years later. Abnormalities in the cutaneous response to ultraviolet radiation at the time of diagnosis, detected by monochromator phototesting, reverted to normal following treatment.

Regulation of cellular growth by the Drosophila target of rapamycin dTOR.

The TOR protein kinases (TOR1 and TOR2 in yeast; mTOR/FRAP/RAFT1 in mammals) promote cellular proliferation in response to nutrients and growth factors, but their role in development is poorly understood. Here, we show that the Drosophila TOR homolog dTOR is required cell autonomously for normal growth and proliferation during larval development, and for increases in cellular growth caused by activation of the phosphoinositide 3-kinase (PI3K) signaling pathway. As in mammalian cells, the kinase activity of dTOR is required for growth factor-dependent phosphorylation of p70 S6 kinase (p70(S6K)) in vitro, and we demonstrate that overexpression of p70(S6K) in vivo can rescue dTOR mutant animals to viability. Loss of dTOR also results in cellular phenotypes characteristic of amino acid deprivation, including reduced nucleolar size, lipid vesicle aggregation in the larval fat body, and a cell type-specific pattern of cell cycle arrest that can be bypassed by overexpression of the S-phase regulator cyclin E. Our results suggest that dTOR regulates growth during animal development by coupling growth factor signaling to nutrient availability.

Cucumber mosaic virus mutants with altered physical properties and defective in aphid vector transmission.

Two mutant strains of cucumber mosaic virus (CMV) were investigated with respect to virion stability and molecular determinants of aphid vector transmission. The mutant 2A1-MT-60x, derived from the mechanically passaged wild type 2A1-AT, is poorly transmissible by the aphid Aphis gossypii and not transmissible by the aphid Myzus persicae, whereas the wild type virus is transmissible by both aphid species. The mutant phenotype was shown to be conferred by a single encoded amino acid change of alanine to threonine at position 162 of the coat protein (CP). Modifying the mutant CP gene to encode the wild type sequence (alanine) at position 162 restored aphid transmission. To test for a correspondence between changes in the physical stability of virions and defects in aphid transmission, a urea disruption assay was developed. Virions of aphid-transmissible strains 2A1-AT and CMV-Fny were stable with treatments of up to between 3 and 4 M urea. In this assay mutant viruses 2A1-MT-60x and CMV-M were less stable, as they were completely disrupted at urea concentrations of 2 and 1 M urea, respectively. The mutant 2A1-MT-60x also accumulated at a reduced level in infected squash relative to the wild type virus. These studies suggest that a primary factor in the loss of aphid transmissibility of some strains of CMV is a reduction in virion stability.

Immunosuppressant PG490 (triptolide) inhibits T-cell interleukin-2 expression at the level of purine-box/nuclear factor of activated T-cells and NF-kappaB transcriptional activation.

PG490 (triptolide) is a diterpene triepoxide with potent immunosuppressive and antiinflammatory properties. PG490 inhibits interleukin(IL)-2 expression by normal human peripheral blood lymphocytes stimulated with phorbol 12-myristate 13-acetate (PMA) and antibody to CD3 (IC50 of 10 ng/ml), and with PMA and ionomycin (Iono, IC50 of 40 ng/ml). In Jurkat T-cells, PG490 inhibits PMA/Iono-stimulated IL-2 transcription. PG490 inhibits the induction of DNA binding activity at the purine-box/antigen receptor response element (ARRE)/nuclear factor of activated T-cells (NF-AT) target sequence but not at the NF-kappaB site. PG490 can completely inhibit transcriptional activation at the purine-box/ARRE/NF-AT and NF-kappaB target DNA sequences triggered by all stimuli examined (PMA, PMA/Iono, tumor necrosis factor-alpha). PG490 also inhibits PMA-stimulated activation of a chimeric transcription factor in which the C-terminal TA1 transactivation domain of NF-kappaB p65 is fused to the DNA binding domain of GAL4. In 16HBE human bronchial epithelial cells, IL-8 expression is regulated predominantly by NF-kappaB, and PG490 but not cyclosporin A can completely inhibit expression of IL-8. The mechanism of PG490 inhibition of cytokine gene expression differs from cyclosporin A and involves nuclear inhibition of transcriptional activation of NF-kappaB and the purine-box regulator operating at the ARRE/NF-AT site at a step after specific DNA binding.

Unique toxic peptides isolated from sawfly larvae in three continents.

D-Amino acid containing peptides have been found to be responsible for sawfly larvae poisoning in many parts of the world. These compounds, unique in the animal kingdom, were isolated from three different species of sawfly indigenous to Australia, Denmark and South America. The octapeptide, lophyrotomin, is the major toxin in the Australian and Danish species and is present in small amounts in the South American sawfly. Pergidin, the main toxin in the South American sawfly, is a heptapeptide containing a phosphoseryl residue. This, as far as we are aware, is the first example of such a peptide to be isolated from an animal source. Small amounts of pergidin have been found in the other two species. All available evidence suggests that both peptides are biosynthesised 'de novo' possibly as a protective device, however it cannot be excluded that microorganisms may be responsible. These compounds are stable to enzymatic breakdown because of their configuration and their strong chemical bonding and lipophilic character provide a potential for residues to remain in the host animal and cause significant changes.

Environmental poisoning: presentation and management.

Environmental poisoning is most commonly associated with chronic long-term exposure to toxins rather than to acute exposure. Such repeated exposure to sublethal doses of compounds and elements presents problems in risk assessment. This is primarily because the data are unavailable to describe relationships between dose and effect at lower levels of exposure to toxins. Bioavailability of toxins also presents a problem because the data on bioavailability are sparse and seldom as high as the default of 100% bioavailability commonly used in risk assessment. Examples are presented of two toxins: arsenic as an elemental anthropogenic and geologic poison and ciguatoxin, a polyether ladder compound, as a toxin produced naturally by dinoflagellates. Bioavailability drives the toxicity of arsenic from contaminated sites, whereas tissue accumulation drives the toxicity of ciguatoxin. Considerable benefit is derived from the harmonization of regulatory processes where there is linkage of health and environmental factors in the derivation of credible risk assessment.

Speciation and absolute bioavailability: risk assessment of arsenic-contaminated sites in a residential suburb in Canberra.

Watson is a fully developed suburb of some 30 years in Canberra (the capital city of Australia). A plunge dip using arsenical pesticides for tick control was operated there between 1946 and 1960. Chemical investigations revealed that many soil samples obtained from the study area contained levels of arsenic exceeding the current health-based investigation levels of 100 mg kg-1 set by the National Healthy and Medical Research Council in Australia. For the speciation study, nine composite samples of surface and sub-surface soils and a composite samples of rocks were selected. ICP-MS analysis showed that arsenic levels in these samples ranged from 32 to 1597 mg kg-1. Chemical speciation of arsenic showed that the arsenite (trivalent) components were 0.32-56% in the soil and 44.8% in the rock composite samples. Using a rat model, the absolute bioavailability of these contaminated soils relative to As3+ or As5+ ranged from 1.02 to 9.87% and 0.26 to 2.98%, respectively. An attempt was made to develop a suitable leachate test as an index of bioavailability. However, the results indicated that there was no significant correlation between the bioavailability and leachates using neutral pH water or 1M HC1. Our results indicate that speciation is highly significant for the interpretation of bioavailability and risk assessment data; the bioavailability fractions of arsenic in soils from Watson are small and therefore the healthy impact upon the environment and humans due to this element is limited.

Speciation of arsenic metabolites in the urine of occupational workers and experimental rats using an optimised hydride cold-trapping method.

A hydride cold-trapping technique was developed and optimised for the measurement of urinary arsenic metabolites. The analytical precision of the method was found to be 6.1, 4.0 and 4.8% (n = 5) for inorganic arsenic (ASi), monomethylarsonate (MMA) and dimethylarsinate (DMA), respectively, with recoveries close to 100%. The detection limits were 1.0, 1.3 and 3 ng for ASi, MMA and DMA, respectively. The method was then used to analyse urine samples obtained from three groups of workers for occupational exposure in three companies where copper chrome arsenate was used for timber treatment. The results were compared with those for a normal control group of laboratory workers. Arsenic and its metabolites were also measured in experimental rats given 5 mg As kg-1 body mass by oral gavage in the form of sodium arsenite, calcium arsenite or sodium arsenate. Occupational workers showed a significantly higher excretion of ASi. Up to two fold increases of urinary ASi excretion in rats compared with control rats were also observed in animals dosed with various forms of arsenicals. The method is suitable for the measurement of arsenic metabolites in urine of both humans and experimental animals.

Effects of inflammation-associated acute-phase response on hepatic and renal indices in the horse.

OBJECTIVES: To determine the effect of an acute soft tissue inflammatory response on biochemical and haematological indices of hepatic and renal function in the Thoroughbred horse. PROCEDURE: Soft tissue inflammation was induced in four Thoroughbred horses by intramuscular injections of Freund's complete adjuvant. The horses were clinically examined and blood and urine samples were collected before and after the adjuvant injections. Biochemical and haematological indices were measured in samples collected and used to determine the onset of the acute-phase response and to assess hepatic and renal function at this time. RESULTS: After adjuvant injection, significant increases (P < 0.01) in total white (13.1 +/- 1.4 x 10(9)/L) and neutrophil (10.2 +/- 1.2 x 109/L) cell counts, rectal temperature (39.7 +/- 0.5 degrees C) and various plasma protein concentrations, including fibrinogen (6.6 +/- 1.2 g/L), haptoglobin (1.3 +/- 0.1 g/L) and total protein (88.1 +/- 2.7 g/L), indicated the induction of an acute-phase response. This corresponded with significant reductions (P < 0.01) in the plasma elimination half-lives (t1/2 beta) sodium bromosulphthalein (3.13 +/- 0.05 to 2.82 +/- 0.07 min) and sodium sulphanilate (38.29 +/- 4.04 to 19.60 +/- 5.68 min) and reductions in the plasma activities of aspartate aminotransferase, glutamate dehydrogenase, creatine kinase, alkaline phosphatase, gamma glutamyl transferase; the urinary creatinine clearance ratios of sodium, chloride and potassium; and the urinary gamma glutamyl transferase-to-creatinine clearance ratios. (All values mean +/- SD.) CONCLUSIONS: The effects of the acute-phase response on indices of hepatic and renal function in the horse suggest that the disposition of pharmacological agents administered at this time may be altered and that indices of acute inflammation should be interpreted cautiously.

Stress response to chronic inflammation in the horse.

Five clinically healthy Thoroughbred geldings were injected with Freund's adjuvant 3 times to induce a chronic inflammatory response. Blood was collected at various times before and after adjuvant administration. Clinical responses (rectal temperature and general demeanor) were also monitored. Adjuvant injection induced increases in rectal temperature and plasma fibrinogen concentration (maximum levels measured were mean +/- s.d. 39.7 +/- 0.5 degrees C and 8.2 +/- 0.3 g/l, respectively), indicative of an inflammatory response. A mild clinical depression was also observed in the horses for 24 h after the first injection of adjuvant only. Plasma cortisol levels decreased significantly from control levels of mean +/- s.d. 187.7 +/- 24.3 nmol/l to a minimum of 80.2 +/- 22.1 nmol/l (P < 0.01) 9 days after the first injection of adjuvant. Conversely, plasma insulin levels increased after the first injection of adjuvant to a maximum (96.7 +/- 15.2 iu/ml; P < 0.01) 12 days later, while plasma glucose concentrations tended to decline. A control group of horses to rule out contemporary environmental influences on the physiological and biochemical indices measured was not included in this study. The results show that chronic inflammation in the horse depressed resting plasma cortisol concentrations.