Dynamics of critical source areas: does connectivity explain chemistry?

Critical source area approaches to catchment management are increasingly being recognised as effective tools to mitigate sediment and nutrient transfers. These approaches often assume hydrological connectivity as a driver for environmental risk, however this assumption has rarely been tested. Using high resolution monitoring, 14 rainfall events of contrasting intensity were examined in detail for spatial and temporal dynamics of overland flow generation at a hydrologically isolated grassland hillslope in Co. Down, Northern Ireland. Interactions between overland flow connectivity and nutrient transfers were studied to test the critical source area hypothesis. While total and soluble phosphorus loads were found to be representative of the size of the overland flow contributing area (P=<0.05), the dynamics of concentrations throughout storm hydrographs were found to be complex and storm dependant. Near linear relationships were observed between the contributing area and total overland flow volumes (R(2)=0.86). Export coefficients (kg ha(-1)) calculated using plot size were found to under estimate annual losses of total phosphorus by a factor of 17, when compared to those calculated using the contributing area. This study shows that current critical source area definitions for implementing mitigation measures may be overlooking the importance of storm characteristics in determining nutrient transfers and hence may be insufficient in determining catchment scale risk.

Use of complementary and alternative medicine in recurrent vulvovaginal candidiasis--results of a practitioner survey

BACKGROUND

The mainstream long term management of recurrent vulvovaginal candidiasis (RVVC) often results in poor outcomes. It is expensive and unacceptable for many women who therefore have incorporated complementary and alternative medicine (CAM) into their personal care plan.

OBJECTIVE

To ascertain clinicians' knowledge of CAM and their recommendations for the use of CAM and non-pharmacological management in women with RVVC.

DESIGN AND SETTING

Anonymous, single page, self completed survey using convenience sampling at a vulval disorders meeting in New South Wales, Australia in 2009.

PARTICIPANTS

Sixty six health professionals (medical practitioners, dermatologists, nurses and allied health professionals).

RESULTS

Most clinicians reported asking about their patients' use of CAM and non-pharmacological management of RVVC, although only around half reported recommending it. CAM management included lactobacillus, oral and vaginal yoghurt, vinegar, garlic, Chinese medicine and tea-tree oil. Non-pharmacological management included dietary changes and use of cotton undergarments. Lactobacillus was the most commonly recommended CAM.

CONCLUSION

CAM is popular with patients and many clinicians actively recommend its use in RVVC despite limited supporting evidence. Further research in the area of CAM and RVVC is long overdue.

Biomimetic collagen scaffolds with anisotropic pore architecture

Sponge-like matrices with a specific three-dimensional structural design resembling the actual extracellular matrix of a particular tissue show significant potential for the regeneration and repair of a broad range of damaged anisotropic tissues. The manipulation of the structure of collagen scaffolds using a freeze-drying technique was explored in this work as an intrinsically biocompatible way of tailoring the inner architecture of the scaffold. The research focused on the influence of temperature gradients, imposed during the phase of crystallisation of collagen suspensions, upon the degree of anisotropy in the microstructures of the scaffolds produced. Moulding technology was employed to achieve differences in heat transfer rates during the freezing processes. For this purpose various moulds with different configurations were developed with a view to producing uniaxial and multi-directional temperature gradients across the sample during this process. Scanning electron microscopy analysis of different cross-sections (longitudinal and horizontal) of scaffolds revealed that highly aligned matrices with axially directed pore architectures were obtained where single unidirectional temperature gradients were induced. Altering the freezing conditions by the introduction of multiple temperature gradients allowed collagen scaffolds to be produced with complex pore orientations, and anisotropy in pore size and alignment.

Identification of a methylation hotspot in the death receptor Fas/CD95 in bladder cancer

We characterized Fas immunoreactivity, functionality and its role in the response to mitomycin-C (MMC) chemotherapy in vitro in cell lines and in vivo in bladder washings from 23 transitional cell carcinoma of the bladder (TCCB) patients, harvested prior to and during MMC intravesical treatment. Having established the importance of functional Fas, we investigated the methylation and exon 9 mutation as mechanisms of Fas silencing in TCCB. For the first time, we report p53 up-regulation in 9/14 and Fas up-regulation in 7/9 TCCB patients during intravesical MMC treatment. Fas immunoreactivity was strong in the TCCB cell line T24 and in 17/20 (85%) tumor samples from patients with advanced TCCB. T24 and HT1376 cells were resistant to MMC and recombinant Fas ligand, whilst RT4 cells were responsive to Fas ligand and MMC. Using RT4 cells as a model, siRNA targeting p53 significantly reduced MMC-induced p53 and Fas up-regulation and stable DN-FADD transfection decreased MMC-induced apoptosis, suggesting that functional Fas enhances chemotherapy responses in a p53-dependent manner. In HT1376 cells, 5-aza-2-deoxycytidine (12 µM) induced Fas immunoreactivity and reversed methylation at CpG site -548 within the Fas promoter. This site was methylated in 13/24 (54%) TCCB patient samples assessed using Methylation-Specific Polymerase Chain Reaction. There was no methylation at either the p53 enhancer region within the first intron or at the SP-1 binding region in the promoter and no mutation within exon 9 in tumor DNA extracted from 38 patients. Methylation at CpG site -548 is a potential target for demethylating drugs.

Getting to the heart of cardiac remodeling; how collagen subtypes may contribute to phenotype

The objective of this study was to investigate the nature and biomechanical properties of collagen fibers within the human myocardium. Targeting cardiac interstitial abnormalities will likely become a major focus of future preventative strategies with regard to the management of cardiac dysfunction. Current knowledge regarding the component structures of myocardial collagen networks is limited, further delineation of which will require application of more innovative technologies. We applied a novel methodology involving combined confocal laser scanning and atomic force microscopy to investigate myocardial collagen within ex-vivo right atrial tissue from 10 patients undergoing elective coronary bypass surgery. Immuno-fluorescent co-staining revealed discrete collagen I and III fibers. During single fiber deformation, overall median values of stiffness recorded in collagen III were 37±16% lower than in collagen I [p<0.001]. On fiber retraction, collagen I exhibited greater degrees of elastic recoil [p<0.001; relative percentage increase in elastic recoil 7±3%] and less energy dissipation than collagen III [p<0.001; relative percentage increase in work recovered 7±2%]. In atrial biopsies taken from patients in permanent atrial fibrillation (n=5) versus sinus rhythm (n=5), stiffness of both collagen fiber subtypes was augmented (p<0.008). Myocardial fibrillar collagen fibers organize in a discrete manner and possess distinct biomechanical differences; specifically, collagen I fibers exhibit relatively higher stiffness, contrasting with higher susceptibility to plastic deformation and less energy efficiency on deformation with collagen III fibers. Augmented stiffness of both collagen fiber subtypes in tissue samples from patients with atrial fibrillation compared to those in sinus rhythm are consistent with recent published findings of increased collagen cross-linking in this setting.

Constitutive activation of JAK2 in mammary epithelium elevates Stat5 signalling, promotes alveologenesis and resistance to cell death, and contributes to tumourigenesis

Signalling through the janus kinase (JAK)/signal transducer and activator of transcription (Stat) pathway is required at different stages of mammary gland development, and this pathway is frequently hyper-activated in cancer, including tumours of the breast. Stats 3, 5 and 6 have important roles in the differentiation and survival of mammary alveolar cells, but somewhat paradoxically, both Stat3 and 5 can have oncogenic activity in the mammary gland. Constitutive activation of JAK2 could be anticipated to result in hyper-activation of Stats 1, 3, 5 and 6 with concomitant cell transformation, although the outcome is difficult to envisage, particularly since Stats 3 and 5 play opposing roles in normal mammary gland development. Here, we show that expression of a constitutively active JAK2 mutant, JAK2 V617F, leads to hyper-activation of Stat5 in mammary epithelial cells (MECs), and transgenic mice expressing JAK2 V617F specifically in the mammary gland exhibit accelerated alveologenesis during pregnancy and delayed post-lactational regression. Overexpressing JAK2 V617F in MECs in vitro results in elevated proliferation and resistance to cell death. Furthermore, constitutively active JAK2 enhances anchorage-independent cell growth in the presence of a co-operating oncogene and accelerates tumourigenesis in a xenograft model. Taken together, our results provide insights into signalling downstream of constitutively active JAK2 and could be important for understanding the molecular mechanisms of breast tumourigenesis.

Effect of varying the phosphorus content of dairy cow diets on losses of phosphorus in overland flow following surface applications of manure

The increasing use of concentrate feedstuffs within Northern Ireland dairy systems has resulted in significant farm gate phosphorus (P) surpluses, and these have contributed to increased soil P levels and risk of P loss to overland flow. However, the P content of feed concentrates can be lowered without compromising animal performance. This study focuses on P losses from grassland and evaluates how adjusting the P content of manure impacts on the P composition and concentration in overland flow. Dairy cows were offered diets containing 5.3 to 3.0 g P kg(-1) dry matter (DM) and produced manures with a range of P contents. Manure was applied at a rate of 50 m3 ha(-1) to 0.5-m2 grassland plots, and simulated rainfall (40 mm h(-1)) was applied repeatedly 2, 9, 28, and 49 d after during the summer, winter, and spring. Decreasing the P content in the diet, from the highest to the lowest P treatment (43%), produced a proportionately greater reduction in manure TP content (63%), but reductions were not exclusively in the water-soluble fraction. Following surface applications of manure, P concentrations in overland flow increased in all seasons (P < or = 0.001), while the greatest impact of varying the manure P content was most evident during the first simulated overland flow event. When diet P content was reduced from 5.4 to 3.0 g P kg(-1) DM, a statistically significant reduction in runoff P concentration was observed in all seasons. Elevated P concentrations in overland flow were observed for 28 d in spring and 9 d in summer and winter. The large drop in P concentrations between simulated rainfall events on Day 2 and Day 9 suggests that increasing the time interval between manure application and the generation of overland flow has a greater impact on P losses than does varying the dietary P content.

Evidence for the production of NO and N2O in two contrasting subsoils following the addition of synthetic cattle urine

Nitrogenous materials can be transferred out of the topsoil, either vertically to a greater depth, or in lateral pathways to surface waters, and they may also become transformed, with the potential of generating environmentally active agents. We measured the production of NO and N(2)O in two contrasting subsoils (70 to 90 cm): one poorly drained and the other freely drained and compared this with the topsoil (0 to 20 cm) of the corresponding soils. The soils were incubated aerobically in jars with subtreatments of either synthetic cattle urine or deionised water and sampled at intervals up to 34 days. (15)N-NO(3)(-) was used to determine the processes responsible for NO and N(2)O production. The headspace was analysed for the concentrations of N(2)O, NO and CO(2) and (15)N enrichment of N(2)O. The soil samples were extracted and analysed for NO(2)(-), NO(3)(-) and NH(4)(+), and the (15)N enrichment of the extracts was measured after conversion into N(2)O and N(2). The study demonstrated the potential for NO, N(2)O and NO(2)(-) to be generated from subsoils in laboratory incubations. Differences in these N dynamics occurred due to subsoil drainage class. In the freely drained subsoil the rates of NO and NO(2)(-) production were higher than those observed for the corresponding topsoil, with mean maximum production rates of 3.5 microg NO(2)(-)-N g(-1) dry soil on day 16 and 0.12 microg NO-N g(-1) dry soil on day 31. The calculated total losses of N(2)O-N as percentages of the applied synthetic urine N were 0.37% (freely drained subsoil), 0.24% (poorly drained subsoil), 0.43% (freely drained topsoil) and 2.09% (poorly drained topsoil). The calculated total losses of NO-N as percentages of the applied synthetic urine N were 1.53% (freely drained subsoil), 0.02% (poorly drained subsoil), 0.25% (freely drained topsoil) and 0.08% (poorly drained topsoil).

Acute cytomegalovirus cholecystitis following renal transplantation

Solid organ transplant recipients are at risk of infection from cytomegalovirus (CMV). A wide range of disease is associated with CMV infection and we report two cases of CMV cholecystitis in patients following renal transplantation. Both patients presented with severe hemorrhagic cholecystitis, which required immediate resuscitation and emergency cholecystectomy. The diagnosis of CMV infection was confirmed in both cases using CMV-specific staining of the gallbladder. The diagnosis of CMV cholecystitis must be considered in all patients with upper abdominal pain after renal transplantation.

Transitory renal failure following rapid administration of a relatively large amount of hematin in a patient with acute intermittent porphyria in clinical remission

Transitory renal failure occurred in a patient with acute intermittent porphyria in clinical remission following i.v. administration of 1 000 mg hematin. The clinical and biochemical picture suggested "acute tubular necrosis", which was followed by a prompt and complete return of renal function without any late sequelae. The renal failure is thought to have resulted from the presence of circulating free hematin, formed as a result of rapid administration of such a relatively large amount. Such a complication has not occurred in patients given hematin for acute porphyric relapse, in whom much smaller amounts have been infused.

Immune cell regulators in mouse mammary development and involution

Dramatic changes in cell composition and function occur in the mammary gland during a pregnancy-lactation-involution cycle. We investigated the transcriptional changes associated with these biological events by using microarray analysis and identified the critical genes involved by using genetically modified mice. Two surprising findings arose from these studies. First, the microarray data showed that postlactational regression was associated with an acute phase inflammatory response, in addition to cell death. Conditional deletion of signal transducer and activator of transcription (Stat)3 or the nuclear factor-kappaB regulatory kinase inhibitor of kappa B kinase beta resulted in a failure of cell death induction during involution, an indication that these signaling pathways are essential mediators of the involution process. Both Stat3 and nuclear factor-kappaB have been shown to regulate acute phase gene expression in addition to apoptosis regulators. Four distinct transcriptional profiles are present in the first 4 d of involution, whereas there are 3 in lactation. At the peak of lactation (i.e., d 10 in mouse), more than 400 genes reach their maximum expression before declining dramatically in the first 12 h of involution. A reciprocal pattern was observed for more than 500 genes that were specifically upregulated within the first 12 h of forced involution. We are now investigating the role of a subset of these genes in involution. We also uncovered a role for genes normally associated with immune cell signaling in the differentiation of luminal mammary epithelial cells during pregnancy. Genetic deletion of the transcription factor Stat6 resulted in delayed development during pregnancy, and this phenotype was recapitulated in mammary tissue from IL-4 and IL-13 doubly deficient mice. Furthermore, we showed that mammary epithelial cells secrete T-cell regulatory cytokines. T-helper type 1 cytokines, such as interferon-gamma and IL-12a, are secreted by undifferentiated mammary epithelial cells, whereas T-helper type 2 cytokines, including IL-4 and IL-13, are secreted by differentiated cells. This unexpected finding demonstrates a role for immune cell signaling in mammary epithelial cell fate and function.

The Stat family of transcription factors have diverse roles in mammary gland development

The Stat family of transcription factors have diverse roles in mammary gland development. Genetic studies in mice have revealed an essential requirement for Stat5a in development of secretory alveolar cells during pregnancy while Stat6, which is normally associated with differentiation of T helper cells, is important in the commitment of luminal cells to this alveolar lineage. In contrast, Stat3 is specifically activated at the initiation of post-lactational regression when it has an essential function in the regulation of cell death and tissue remodelling. Stat1 and Stat4 have been shown to be regulated during a mammary developmental cycle although whether they have specific, non-redundant roles is not clear. Thus, the adult mammary gland is somewhat unusual in that it is a tissue where different Stats are sequentially activated to orchestrate the processes of functional differentiation, cell death and tissue remodelling.

Increase in phosphorus losses from grassland in response to Olsen-P accumulation

The Olsen-P status of grazed grassland (Lolium perenne L.) swards in Northern Ireland was increased over a 5-yr period (March 2000 to February 2005) by applying different rates of P fertilizer (0, 10, 20, 40, or 80 kg P ha(-1) yr(-1)) to assess the relationship between soil P status and P losses in land drainage water and overland flow. Plots (0.2 ha) were hydrologically isolated and artificially drained to v-notch weirs, with flow proportional monitoring of drainage water and overland flow. Annually, the collectors for overland flow intercepted between 11 and 35% of the surplus rainfall. Single flow events accounted for up to 52% of the annual dissolved reactive phosphorus (DRP) load. The Olsen-P status of the soil influenced DRP and total phosphorus (TP) concentrations in land drainage water and overland flow. Annual TP loss was highly variable and ranged from 0.19 to 1.55 kg P ha(-1) yr(-1) for the plot receiving no P fertilizer and from 0.35 to 2.94 kg P ha(-1) yr(-1) for the plot receiving 80 kg P ha(-1) yr(-1). Despite the Olsen-P status in the soils ranging from 22 to 99 mg P kg(-1), after 5 yr of fertilizer P applications it was difficult to identify a clear Olsen-P concentration at which P losses increased. Any relationship was confounded by annual variability of hydrologic events and flows and by hydrologic differences between plots. Withholding P fertilizer for over 5 yr was not long enough to lower P losses or to have an adverse effect on herbage P concentrations.

Sleep and GABA levels in the oral part of rat pontine reticular formation are decreased by local and systemic administration of morphine

Morphine, a mu-opioid receptor agonist, is a commonly prescribed treatment for pain. Although highly efficacious, morphine has many unwanted side effects including disruption of sleep and obtundation of wakefulness. One mechanism by which morphine alters sleep and wakefulness may be by modulating GABAergic signaling in brain regions regulating arousal, including the pontine reticular nucleus, oral part (PnO). This study used in vivo microdialysis in unanesthetized Sprague-Dawley rat to test the hypothesis that mu-opioid receptors modulate PnO GABA levels. Validation of the high performance liquid chromatographic technique used to quantify GABA was obtained by dialyzing the PnO (n=4 rats) with the GABA reuptake inhibitor nipecotic acid (500 microM). Nipecotic acid caused a 185+/-20% increase in PnO GABA levels, confirming chromatographic detection of GABA and demonstrating the existence of functional GABA transporters in rat PnO. Morphine caused a concentration-dependent decrease in PnO GABA levels (n=25 rats). Coadministration of morphine (100 microM) with naloxone (1 microM), a mu-opioid receptor antagonist, blocked the morphine-induced decrease in PnO GABA levels (n=5 rats). These results show for the first time that mu-opioid receptors in rat PnO modulate GABA levels. A second group of rats (n=6) was used to test the hypothesis that systemically administered morphine also decreases PnO GABA levels. I.v. morphine caused a significant (P<0.05) decrease (19%) in PnO GABA levels relative to control i.v. infusions of saline. Finally, microinjections followed by 2 h recordings of electroencephalogram and electromyogram tested the hypothesis that PnO morphine administration disrupts sleep (n=8 rats). Morphine significantly (P<0.05) increased the percent of time spent in wakefulness (65%) and significantly (P<0.05) decreased the percent of rapid eye movement (REM) sleep (-53%) and non-REM sleep (-69%). The neurochemical and behavioral data suggest that morphine may disrupt sleep, at least in part, by decreasing GABAergic transmission in the PnO.