A single strain of Tetratrichomonas gallinarum causes fatal typhlohepatitis in red-legged partridges (Alectoris rufa) to be distinguished from histomonosis

Typhlohepatitis was observed in a flock of 2500 red-legged partridges in Great Britain, characterized by the sudden deaths of 15 birds within 2 days. Necropsy of five dead birds revealed severe lesions in the caeca with thickened caecal walls, a reddened lining and bloody contents. The livers contained multiple miliary lesions and similar pathological changes were found in the spleens of some birds. Microscopic examination of intestinal contents showed the occurrence of coccidial oocysts in two partridges. Different methods for the detection of bacteria from liver and intestine samples were conducted without positive results. Histopathological examination revealed the presence of protozoan parasites in the caecum, liver and spleen of the affected birds. In situ hybridization (ISH) for the detection of trichomonads resulted in positive findings and polymerase chain reaction (PCR) confirmed the presence of Tetratrichomonas gallinarum in the lesions. Additionally, archived tissues of red-legged partridges from different flocks suffering from severe typhlohepatitis in Great Britain in 2008 and 2009 were re-investigated by ISH and PCR. Beside the sporadic occurrence of histomonosis, in most of the cases trichomonads were detected by ISH in the caecum and liver of affected birds. Furthermore, dissemination of the flagellate into the lung and bursa of Fabricius could be demonstrated. Analyses of T. gallinarum DNA obtained from the different cases resulted in homologous nucleotide sequences. Altogether, the results demonstrate the circulation of a virulent strain of T. gallinarum in reared red-legged partridges.

The effect of serum matrix and gender on cortisol measurement by commonly used immunoassays

Background

Considerable intermethod bias has been observed between cortisol immunoassays, with some also displaying a gender difference. Cortisol immunoassay performance is affected by serum matrix effects such as changes in steroid binding proteins and presence of interfering steroids which can be altered in various clinical settings. This study investigates cortisol immunoassay bias in pregnancy, renal failure and intensive care patients.

Methods

Serum remaining after routine analysis from pregnant patients, patients on the intensive care unit and patients with renal failure were obtained prior to disposal and used to create 20 anonymous samples per group. A male and female serum pool was prepared and spiked with cortisol. Samples were aliquoted and distributed to four hospitals for cortisol analysis by immunoassays from four different manufacturers. Cortisol was also measured by an isotope dilution-gas chromatography–mass spectrometry method for comparison of assay bias.

Results

Differences in cortisol immunoassay bias were observed across the different patient groups. A negative bias compared to pooled serum samples was observed for pregnancy serum, whilst a more positive bias was seen in renal failure and intensive care patients. Variation in bias was greatest in renal failure with the Roche E170 the most affected and the Abbott architect the least (interquartile ranges 44% and 14%, respectively).

Conclusions

Cortisol immunoassay bias may be affected by gender and differences in serum matrix from patients with various clinical conditions. Users of cortisol assays should be aware of differing matrix effects on their assay and the relevance of these for the interpretation of clinical results.

Adult testosterone and calculated free testosterone reference ranges by tandem mass spectrometry

BACKGROUND

Testosterone is measured for the investigation of female hyperandrogenism and male hypogonadism. Liquid chromatography-tandem mass spectrometry (tandem MS) is becoming the method of choice but comprehensive reference ranges are lacking.

METHODS

Testosterone was measured by tandem MS on 90 healthy women, 67 young healthy men and pregnant women (59 first trimester and 60 second trimester).

RESULTS

The male, male calculated free, first trimester and second trimester testosterone reference ranges (derived using the antilog of mean ± 1.96 SD of log transformed data) were 10.6-31.9, 0.23-0.63, 0.6-4.9 and 0.9-4.9 nmol/L, respectively. The female testosterone upper reference range limit, derived non-parametrically from the 97.5th centile, was <1.7 nmol/L.

CONCLUSIONS

We have derived tandem MS testosterone reference ranges to support clinical services.

Cell cytometry with a light touch: sorting microscopic matter with an optical lattice

Lab-on-a-chip design is a key technology for increasing both the reliability and the functionality of many different preparation and diagnostic techniques in biomedicine. The drive towards ever more integrated lab-on-a-chip designs requires increasingly complex microfluidic systems. In order to build these systems, non-invasive actuators such as pumps, filters and mixers are required. We have demonstrated microfluidic sorting based on a 3D interference pattern, formed from multiple coherent laser beams, which has the potential to fulfil all the above criteria. By interfering five laser beams from a fibre laser at 1070 nm, we have formed a 3D optical lattice. When particles flow through the optical lattice their trajectories depend upon the force exerted on the particle by the optical lattice, in combination with the drag force exerted by the fluid flow. Hence, with the strength of a particle's interaction with the lattice determining the total force exerted upon it, its trajectory is determined by its physical properties. These properties include refractive index, size and shape, giving a range of criteria with which to sort an analyte. We have shown separation at 45 degrees of polymer from silica microspheres (by refractive index), the separation of protein microcapsules and the sorting of erythrocytes from lymphocytes. The interference pattern can be tailored to the particles and if a blockage occurs, the laser can simply be switched off, unlike solid-state micro-sorters, so that no jamming occurs. Efficiencies in excess of 95% have been achieved.

Soluble guanylyl cyclase activator YC-1 protects white matter axons from nitric oxide toxicity and metabolic stress, probably through Na(+) channel inhibition

In the rat isolated optic nerve, nitric oxide (NO) activates soluble guanylyl cyclase (sGC), resulting in a selective accumulation of cGMP in the axons. The axons are also selectively vulnerable to NO toxicity. The experiments initially aimed to determine any causative link between these two effects. It was shown, using a NONOate donor, that NO-induced axonal damage occurred independently of cGMP. Unexpectedly, however, the compound YC-1, which is an allosteric activator of sGC, potently inhibited NO-induced axonopathy (IC(50) = 3 microM). This effect was not attributable to increased cGMP accumulation. YC-1 (30 microM) also protected the axons against damage by simulated ischemia, which (like NO toxicity) is sensitive to Na(+) channel inhibition. Although chemically unrelated to any known Na(+) channel inhibitor, YC-1 was effective in two biochemical assays for activity on Na(+) channels in synaptosomes. Electrophysiological recording from hippocampal neurons showed that YC-1 inhibited Na(+) currents in a voltage-dependent manner. At a concentration giving maximal protection of optic nerve axons from NO toxicity (30 microM), YC-1 did not affect normal axon conduction. It is concluded that the powerful axonoprotective action of YC-1 is unrelated to its activity on sGC but is explained by a novel action on voltage-dependent Na(+) channels. The unusual ability of YC-1 to protect axons so effectively without interfering with their normal function suggests that the molecule could serve as a prototype for the development of more selective Na(+) channel inhibitors with potential utility in neurological and neurodegenerative disorders.

Human osteoclast formation from blood monocytes, peritoneal macrophages, and bone marrow cells

Mononuclear precursors of the human osteoclast have been identified in both bone marrow and the circulation in man, but osteoclast membership of the mononuclear phagocyte system (MPS) and its precise cellular ontogeny remain controversial. We isolated human hematopoietic marrow cells, blood monocytes, and peritoneal macrophages and incubated each of these cell populations with UMR106 osteoblast-like cells on glass coverslips and dentine slices in both the presence and absence of 1,25 dihydroxyvitamin D3 (1,25(OH)2D3), macrophage-colony stimulating factor (M-CSF), and dexamethasone. Cells isolated from peripheral blood and peritoneal dialysis fluid were positive only for monocyte/macrophage markers (CD11a, CD11b, CD14, and HLA-DR) and negative for osteoclast markers [tartrate-resistant acid phosphatase (TRAP), vitronectin reception (VNR), and calcitonin (CT) receptors and did not form resorption pits on dentine slices after 24 hours in culture. Similarly marrow cells did not form resorption pits on dentine slices after 24 hours in culture. However, after 14 days in co-culture with UMR106 cells, in the presence of 1,25(OH)2D3 and M-CSF, numerous TRAP, CT receptor, and VNR-positive multinucleated cells capable of extensive lacunar resorption were formed in co-cultures of all these preparations. The presence of 1,25 (OH)2D3, M-CSF, and UMR106 were absolute requirements for osteoclast differentiation. It is concluded that precursor cells capable of osteoclast differentiation are present in the marrow compartment, the monocyte fraction of peripheral blood, and in the macrophage compartment of extraskeletal tissues and that these cells are capable of differentiating into mature functional osteoclasts. These findings argue in favor of osteoclast membership of the human MPS.

Human arthroplasty derived macrophages differentiate into osteoclastic bone resorbing cells

OBJECTIVE

In aseptic loosening, a heavy macrophage response to biomaterial wear particles is commonly found in arthroplasty tissues. The aim of this study was to discover if these cells contribute to the bone resorption of aseptic loosening by differentiating into osteoclasts.

METHODS

Macrophages were isolated from the pseudocapsule and pseudomembrane of loose cemented and uncemented hip arthroplasties at the time of revision surgery and then co-cultured on glass coverslips and dentine slices with UMR 106 rat osteoblast-like cells, both in the presence and absence of 1,25 dihydroxyvitamin D3 [1,25(OH)2D3]. Macrophages isolated from the synovial membrane of patients with osteoarthritis (OA) undergoing hip replacements were similarly studied as a control group.

RESULTS

After 24 hours incubation, most cells isolated from the above periprosthetic tissues strongly expressed macrophage (CD11b, CD14) but not osteoclast markers. However, after 14 days incubation, numerous multinucleated cells showing the phenotypic features of osteoclasts (that is, positive for tartrate resistant acid phosphatase, the vitronectin receptor, and capable of extensive lacunar resorption) formed in co-cultures of arthroplasty derived macrophages and UMR 106 cells, in the presence of 1,25(OH)2D3. The addition of an antibody to macrophage colony stimulating factor (M-CSF) considerably reduced macrophage-osteoclast differentiation and hence the lacunar resorption seen in these co-cultures. In contrast, OA synovial macrophage/UMR 106 co-cultures showed little or no evidence of macrophage-osteoclast differentiation and this was only seen when human M-CSF was added to the co-cultures.

CONCLUSION

This is the first report showing that human macrophages isolated directly from periprosthetic tissues surrounding loosened implants can differentiate into multinucleated cells showing all the functional and cytochemical characteristics of osteoclasts. In contrast with other macrophage populations, exogenous M-CSF is not required for this to occur. In the context of the heavy macrophage response to wear particles in periprosthetic tissues macrophage-osteoclast differentiation may represent an important cellular mechanism whereby osteolysis is effected in aseptic loosening.

Human osteoclast formation and bone resorption by monocytes and synovial macrophages in rheumatoid arthritis

OBJECTIVE

To determine whether synovial macrophages and monocytes isolated from patients with rheumatoid arthritis patients are capable of differentiating into osteoclastic bone resorbing cells; and the cellular and humoral conditions required for this to occur.

METHODS

Macrophages isolated from the synovium and monocytes from the peripheral blood of rheumatoid arthritis patients were cultured on bone slices and coverslips, in the presence and absence of UMR 106 rat osteoblast-like cells, 1,25-dihydroxy vitamin D3 (1,25(OH)2D3) and macrophage colony stimulating factor (M-CSF), and assessed for cytochemical and functional evidence of osteoclast differentiation.

RESULTS

Isolated calcitonin receptor (CTR), tartrate resistant acid phosphatase (TRAP), and vitronectin receptor (VNR) negative, CD11b and CD14 positive monocytes and macrophages differentiated into CTR, TRAP, and VNR positive multinucleated cells capable of extensive lacunar bone resorption when co-cultured for 14 d with UMR 106 cells in the presence 1,25(OH)2D3 and M-CSF.

CONCLUSIONS

Mononuclear phagocytes (monocytes and macrophages) from rheumatoid arthritis patients are capable of differentiating into multinucleated cells showing all the cytochemical and functional criteria of mature osteoclasts. Synovial macrophage-osteoclast differentiation may represent an important cellular mechanism in the bone destruction associated with rheumatoid arthritis.

The nitric oxide-cyclic GMP pathway is required for nociceptive signalling at specific loci within the somatosensory pathway

The involvement of nitric oxide in nociceptive processing was examined at the main loci of synaptic transmission within the rat somatosensory pathway from the caudal sural cutaneous nerve. Intrathecal (lumbar 1-3) administration of the nitric oxide synthase inhibitor, N omega-nitro-L-arginine methyl ester (30 micrograms), inhibited nitric oxide synthase in this region of the spinal cord by greater than 80% but had no significant effect on nitric oxide synthase in parietal cerebral cortex, thalamus or medulla/pons. In a rat model of peripheral neuropathy (one to two week ligation of the caudal sural cutaneous nerve), intrathecal administration of the same dose of N omega-nitro-L-arginine methyl ester prevented the hyperalgesic response to thermal stimuli. Administration of 30 micrograms N omega-nitro-L-arginine methyl ester into the lateral ventricle had no effect on nitric oxide synthase in the lumbar 1-3 region of the spinal cord but gave substantial inhibition in higher areas of the somatosensory pathway (parietal cerebral cortex, thalamus and medulla/pons). Nitric oxide synthase in the parietal cerebral cortex (but not thalamus) was inhibited to a greater extent in the hemisphere ipsilateral to the site of administration. Administration of 30 micrograms N omega-nitro-L-arginine methyl ester into the lateral ventricle decreased thermal hyperalgesia, but only when N omega-nitro-L-arginine methyl ester was administered contralateral to the ligated caudal sural cutaneous nerve and therefore ipsilateral to the cortical nociceptive processing from this nerve. Intrathecal and intracerebroventricular administration of the selective inhibitor of nitric oxide-sensitive guanylyl cyclase, 1-H-[1,2,4]oxadiazalo[4,3-a]quinoxalin-1-one, also decreased the hyperalgesic response to thermal stimuli. These data demonstrate that, in a model of neuropathic pain, nitric oxide is involved in nociceptive processing at spinal and cerebrocortical synaptic loci of the somatosensory pathway and that its actions appear to be mediated through guanylyl cyclase.

Magnetic compass cues and visual pattern learning in honeybees

We show that honeybees can learn to distinguish between two 360 &deg; panoramic patterns that are identical except for their compass orientation; in this case, the difference was a 90 &deg; rotation about the vertical axis. To solve this task, bees must learn the patterns with respect to a directional framework. The most powerful cue to direction comes from the sky, but discrimination between patterns is possible in the absence of celestial information. Under some conditions, when other potential directional cues have been disrupted, we show that bees can use a magnetic direction to discriminate between the patterns.

Legionellaceae in the potable water of Nova Scotia hospitals and Halifax residences

Water was cultured from 39 of 48 hospitals (7 Halifax hospitals and 32 non-Halifax hospitals) in the province of Nova Scotia and from 90 residences (74 private dwellings, 16 apartments) in Halifax to determine the frequency of legionella contamination. Six of seven Halifax hospitals had Legionellaceae isolated from their potable water compared with 3 of 32 non-Halifax hospitals (P < 0.0001). Overall, 19 of 59 (32%) of the water samples from Halifax hospitals were positive for legionellae compared with 5 of 480 (1%) samples from non-Halifax hospitals (P < 0.0000). Five of the six positive Halifax hospitals had Legionella pneumophila serogroup 1 and 1 had L. longbeachae serogroup 2 recovered from their potable water. Legionella contamination was associated with older, larger (> or = 50 beds) hospitals with total system recirculation. These hospitals also had water with a higher pH and calcium content but lower sodium, potassium, nitrate, iron and copper content. Fourteen of the 225 (6.2%) water samples from Halifax residences were positive for legionellae -8% (6/74) of the single family dwellings were positive, compared with 25% (4/16) apartments. The positivity rate of 15.7% for the 19 electric hot-water heaters in Halifax homes was not significantly different from the 32% positivity for Halifax hospitals. L. longbeachae accounted for 2 of the 14 isolates of legionellae from Halifax homes.

Arterial oxygen saturation in preterm neonates without respiratory failure

To obtain normal data on arterial oxygen saturation as measured by pulse oximetry (SpO2; Nellcor N200), we obtained 12-hour tape recordings of SpO2, photoplethysmographic waveforms, instantaneous pulse rate, and observations of breathing movements on 55 preterm neonates (25 girls) who had been admitted to one of four special care baby units but had no signs of respiratory distress and were breathing room air at 24 hours of age. Their median gestational age at birth was 35 weeks (range, 30 to 36), and their median age at the time of study 1 day (range, 1 to 7). Median baseline SpO2, measured only during regular breathing, was 99.4% (range, 90.7 to 100; 5th percentile, 95.5). Ten recordings (18%) contained a total of 83 episodes of desaturation (defined as a fall in SpO2 to < or = 80% for > or = 4 seconds). The 95th percentile for desaturation frequency was eight per recording. One infant had 55 episodes of desaturation and thus accounted for two thirds of all episodes observed. Only one of the episodes of desaturation in this infant, and none of those in the other nine infants, had been noted clinically, nor had the abnormally low baseline SpO2 (90.7%) in one infant. Baseline SpO2 in these nondistressed preterm neonates was higher than might be expected, given the SpO2 levels currently recommended for preterm infants with respiratory failure. A minority of infants, however, had a low baseline SpO2 or a high frequency of episodes of desaturation, the potential effects of which remain to be determined.

Development changes to gut microflora metabolism in mice

Developmental changes in the activities of bacterial nitrate reductase, nitroreductase and beta-glucuronidase and their response to fermentable dietary fibre, were investigated in caecal contents from suckling mice (2-week-old) and in mice aged 4-24 weeks fed either a purified fibre-free diet or that diet supplemented with 5% (w/w) pectin. There was no apparent age-related trend common to the three enzymes studied. Nitrate reductase activity in the mice fed the fibre-free diet did not markedly alter with age. Pectin administration, however, was associated with a significant increase in nitrate reductase activity, particularly in 4-week-old mice. Nitroreductase activity exhibited an overall upward trend in mice from 2 to 12 weeks and thereafter decreased. Caecal beta-glucuronidase activity in mice increased sharply between 2 weeks and 4 weeks of age, thereafter not changing significantly until the 24th week. Pectin feeding had no consistent effect on activities either of nitroreductase or beta-glucuronidase. The changes in enzyme activities with age were not related to the concentration of bacteria in the caecum, which was highest in the 2-week-old mice. We conclude that the weaning is a period in which marked changes in caecal bacterial enzyme activities can occur.

Developmental changes in hepatic activation of dietary mutagens by mice

Metabolic activation of the food mutagens 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and aflatoxin B1 by female BALB/c mice of different ages (2-24 weeks) was investigated in vivo and in vitro using Salmonella typhimurium TA98 as the indicator organism. The in vivo activation of the three mutagens was investigated in 4- and 24-week-old mice using an intrasanguineous host-mediated assay. All three compounds showed reduced levels of activation with the older hosts. Hepatic S9 fractions from female mice of varying ages between 2 and 24 weeks were used in the in vitro mutagenicity assay. To achieve optimal activation to bacterial mutagens, 5% S9 was required for aflatoxin B1 and Trp-P-2 and 10% S9 for MeIQ; age of donor generally had little effect on the profile of these protein activation curves. Under these optimal conditions MeIQ and Trp-P-2 both exhibited, as before, age-dependent decreases in activation over a wide range of mutagen concentrations, however the in vitro activation of aflatoxin showed no consistent change with age. Spectrophotometric measurements of S9 cytochrome P-450 content showed a decrease in concentration with increasing age, but this was not sufficient to account for changes observed in hepatic mutagen activation. However, changes in the activities of certain cytochrome P-450 isoenzymes and cytosolic GSH-transferases, which in turn result in changes in the activation and detoxification capacity of the liver, would appear to explain age-dependent changes in the activity of mutagens in vivo.

The effect of ascorbic acid on the amine-nitrite and nitrosamine mutagenicity in bacteria injected into mice

Ascorbic acid was tested for its ability to increase or decrease the induction of bacterial mutations by dimethylnitrosamine (DMN) or aminopyrine plus nitrite within intact mice. No evidence was found of the mutagenicity of ascorbic acid itself when tested alone or in the presence of copper ions. Similarly, no increase or decrease in the DMN-induced mutation frequency was observed. However, ascorbic acid was found to decrease the aminopyrine/nitrite-induced mutation frequency to an extent which was dependent on the experimental conditions used.

Natulan, a bacterial mutagen requiring complex mammalian metabolic activation

Following administration of Natulan and Escherichia coli to mice a dose-dependent increase in the frequency of induced bacterial mutations was observed. This mutation response was dependent on the route of Natulan administration and, following short exposures, was limited by the rate of metabolic activation of the compound.

Physiological modification of alkylating agent induced mutagenesis. II. Influence of the numbers of chromosome replicating forks and gene copies on the frequency of mutations induced in Escherichia coli

The frequency of reversions induced in Escherichia coli K-12 trpA58 by any of five different monofunctional alkylating agents increased as the growth rate of the organism was raised prior to mutagen treatment. The increase in mutation frequency did not correlate with growth rate-dependent changes in cell area or total cellular protein and DNA. After treatment of cells with N-methyl-N-nitrosourea (MNUA), no growth rate-dependent change was observed in the total DNA alkylation or percentage of O6-methylguanine present in the DNA extracted. The frequency of reversions induced by one mutagen, methyl methanesulphonate (MMS), increased in proportion to the average number of trpA gene copies per cell, whereas the frequency of reversions induced by the other compounds was dependent on the average number of chromosome replicating forks per cell. This difference was attributed to the different ratios of DNA base alkylation products observed, formed after treatment with MMS, an SN2-type reagent, or after treatment with the SN1-type reagents ethyl methanesulphonate (EMS), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), MNUA and N-ethyl-N-nitrosourea (ENUA). Possible reasons for the dependence of mutation frequency on the number of replicating forks per cell are discussed.

Physiological modification of alkylating-agent induced mutagenesis. I. Effect of growth rate and repair capacity on nitrosomethylurea-induced mutation of Escharichia coli

The effects of repair capacity and growth rate on the induction of mutations by N-methyl-N-nitosourea (MNUA) was investigated using the trpE reversion system of Escherichia coli WP2 and some repair-deficient derivatives isogenic for this gene. In all these strains reducing the growth rate prior to MNUA-treatment caused a reduction in the mutational response, however major differences were observed between strains. In exrA and recA- bacteria stationary phase cells were 100 times less mutable than cells grown at a mean generation time (m.g.t.) of 30 min, whereas reductions of 12 and 25 times were observed in the uvrA- and wild-type strains respectively. In contrast the mutational response of the polA- mutant varied only slightly with growth rate; the increases at high MNUA concentrations being equal to the increase in the trpE gene number. These results show the increasing importance of the error-prone exrA+/recA+-dependent repair system in mutation-induction by MNUA as the growth rate of the culture is reduced and its relative unimportance for mutation induction in nutrient broth-grown cells (m.g.t. 30 min).

The effect of isoprenaline on induction of tumours by methyl nitrosourea in the salivary and mammary glands of female wistar rats

Pretreatment of rats with isoprenaline sulphate (IPR) stimulated DNA synthesis in both salivary and mammary gland tissues. Salivary gland tumours induced by N-methyl-N-nitrosourea (MNU) were observed for the first time in rats, but occurred only in IPR-pretreated animals given MNU during the period of IPR-stimulated DNA synthesis. The cumulative index of MNU-induced mammary tumours and the number of tumours per tumour-bearing rat were increased by IPR-pretreament only if the animals received MNU during the period of IPR-stimulated DNA synthesis.