Improving the capacity of researchers and bereaved parents to co-design and translate stillbirth research together.

BACKGROUND: Working with bereaved parents in co-designed stillbirth research, policy and practice is essential to improving care and outcomes. PROBLEM: Effective parent engagement is often lacking. This may be due to bereaved parents not feeling adequately and appropriately supported to be involved. AIM: To consult bereaved parents with the aim to understand their experiences, attitudes, and needs around involvement in stillbirth research and gain feedback about the usefulness and appropriateness of a proposed co-designed guide to support their involvement, including content and design aspects of this resource. METHODS: An online co-designed survey was disseminated via Australian parent support organisations social media in August 2022. FINDINGS: All 90 respondents were bereaved parents, 94% (n = 85) were female. Two-thirds (67%, n = 60) had never participated in stillbirth research, 80% (n = 72) agreed involvement of bereaved parents in research was important or extremely important and 81% (n = 73) were interested in future research involvement. Common motivations for involvement were wanting to leave a legacy for their baby and knowing research outcomes. Common barriers included not having been asked to participate or not knowing how. Most (89%, n = 80) agreed the proposed guide would be useful. Highly valued topics were the importance of bereaved parents' voices in stillbirth research and how they can make a difference. CONCLUSION: The majority of bereaved parents we surveyed want to be involved in stillbirth research and would value a resource to support this. The proposed concept and content for a co-designed guide to aid engagement was well supported.

Neonatal near-miss audits: a systematic review and a call to action.

BACKGROUND: Neonatal near-miss (NNM) can be considered as an end of a spectrum that includes stillbirths and neonatal deaths. Clinical audits of NNM might reduce perinatal adverse outcomes. The aim of this review is to evaluate the effectiveness of NNM audits for reducing perinatal mortality and morbidity and explore related contextual factors. METHODS: PubMed, Embase, Scopus, CINAHL, LILACS and SciELO were searched in February/2023. Randomized and observational studies of NNM clinical audits were included without restrictions on setting, publication date or language. PRIMARY OUTCOMES: perinatal mortality, morbidity and NNM. SECONDARY OUTCOMES: factors contributing to NNM and measures of quality of care. Study characteristics, methodological quality and outcome were extracted and assessed by two independent reviewers. Narrative synthesis was performed. RESULTS: Of 3081 titles and abstracts screened, 36 articles had full-text review. Two studies identified, rated, and classified contributing care factors and generated recommendations to improve the quality of care. No study reported the primary outcomes for the review (change in perinatal mortality, morbidity and NNM rates resulting from an audit process), thus precluding meta-analysis. Three studies were multidisciplinary NNM audits and were assessed for additional contextual factors. CONCLUSION: There was little data available to determine the effectiveness of clinical audits of NNM. While trials randomised at patient level to test our research question would be difficult or unethical for both NNM and perinatal death audits, other strategies such as large, well-designed before-and-after studies within services or comparisons between services could contribute evidence. This review supports a Call to Action for NNM audits. Adoption of formal audit methodology, standardised NNM definitions, evaluation of parent's engagement and measurement of the effectiveness of quality improvement cycles for improving outcomes are needed.

Knowing your audience: Investigating stillbirth knowledge and perceptions in the general population to inform future public health campaigns.

BACKGROUND: The prevalence of stillbirth in many high income countries like Australia has remained unchanged for over 30 years. The 2018 Australian government Senate Select Committee on Stillbirth Research and Education highlighted the need for a public health campaign to encourage public conversations and increase awareness. However, there is little evidence about the community's knowledge and perceptions towards pregnancy and stillbirth, nor their aspirations for a public health campaign. AIMS: To assess the general knowledge, perceptions, myths and attitudes towards stillbirth to inform future public health campaigns. METHODS: Australian participants (n = 344; predominately women n = 294 (85.5%)) were recruited via Facebook.com. They completed a cross-sectional online survey designed to assess their knowledge of pregnancy and stillbirth, with additional questions on socio-demographic characteristics. RESULTS: Stillbirth knowledge and awareness of incidence was low in this sample. Prominent myths, such as baby runs out of room in the uterus (n = 112, 33%) and baby slows down when preparing for labour (n = 24, 27%) were endorsed. Only 25% (n = 85) knew the prevalence of stillbirth in Australia (six per day). Almost two-thirds (n = 205; 62%) agreed that there needs to be a public health campaign, however one in five (n = 65; 20%) were concerned that talking about stillbirth with pregnant women may cause them to worry. DISCUSSION AND CONCLUSION: Our findings reinforce the need for a targeted campaign, which educates the general population about the definition and prevalence of stillbirth, stillbirth risks and modifiable health behaviours. Appropriate messaging should target pregnant women during antenatal care as well as their support and care systems (family, friends, and care providers).

Generation of goats by nuclear transfer: a retrospective analysis of a commercial operation (1998-2010).

At LFB USA, Inc., the ultimate use for transgenic cloned goats is for the production of recombinant human protein therapeutics in their milk. This retrospective analysis of the Somatic Cell Nuclear Transfer (SCNT) program, spanning from 1998 to 2010, examined parameters potentially affecting the outcomes and efficiencies in this commercial operation. Over 37,000 + ova were utilized in the SCNT protocol producing a total of 203 cloned goats. Fifty one (51) clones were produced from non-transfected (transgenic and non-transgenic animal donor) cell lines and 152 clones were produced from transfected cell lines. Comparisons and summaries of (a) transfected versus non-transfected cell lines, (b) relationship of SCNT parameters to offspring produced, (c) skin versus fetal cells, (d) fresh versus cryopreserved cells, (e) parameters from all cell lines used versus those producing SCNT offspring, (f) variation among cell sources, (g) methods of SCNT parturition management and effects on live offspring, and lastly (h) SCNT variation by program are reported. Findings indicate that (a) non-transfected cell lines were more efficient versus transfected cell lines in generating viable cloned offspring on a per reconstructed embryo transferred basis, (b) transfected fetal fibroblasts had improved efficiency versus transfected skin fibroblasts, (c) the percentage of non-transfected cell lines that produced offspring was statistically higher than transfected cell lines, (d) and induction of parturition improved the percentage of viable offspring. In summary, this retrospective analysis on the SCNT process has identified certain parameters for improved efficiency in producing viable cloned goats in a commercial setting.

Neutralising antibodies in Spike mediated SARS-CoV-2 adaptation.

SARS-CoV-2 Spike protein is critical for virus infection via engagement of ACE2, and amino acid variation in Spike is increasingly appreciated. Given both vaccines and therapeutics are designed around Wuhan-1 Spike, this raises the theoretical possibility of virus escape, particularly in immunocompromised individuals where prolonged viral replication occurs. Here we report chronic SARS-CoV-2 with reduced sensitivity to neutralising antibodies in an immune suppressed individual treated with convalescent plasma, generating whole genome ultradeep sequences by both short and long read technologies over 23 time points spanning 101 days. Although little change was observed in the overall viral population structure following two courses of remdesivir over the first 57 days, N501Y in Spike was transiently detected at day 55 and V157L in RdRp emerged. However, following convalescent plasma we observed large, dynamic virus population shifts, with the emergence of a dominant viral strain bearing D796H in S2 and ΔH69/ΔV70 in the S1 N-terminal domain NTD of the Spike protein. As passively transferred serum antibodies diminished, viruses with the escape genotype diminished in frequency, before returning during a final, unsuccessful course of convalescent plasma. In vitro, the Spike escape double mutant bearing ΔH69/ΔV70 and D796H conferred decreased sensitivity to convalescent plasma, whilst maintaining infectivity similar to wild type. D796H appeared to be the main contributor to decreased susceptibility, but incurred an infectivity defect. The ΔH69/ΔV70 single mutant had two-fold higher infectivity compared to wild type and appeared to compensate for the reduced infectivity of D796H. Consistent with the observed mutations being outside the RBD, monoclonal antibodies targeting the RBD were not impacted by either or both mutations, but a non RBD binding monoclonal antibody was less potent against ΔH69/ΔV70 and the double mutant. These data reveal strong selection on SARS-CoV-2 during convalescent plasma therapy associated with emergence of viral variants with reduced susceptibility to neutralising antibodies.

Empirical engineering models for airborne respirable dust capture from water sprays and wet scrubbers.

Airborne respirable coal dust capture by water sprays or wet scrubbers has been studied and developed over many decades as an engineering control to reduce dust exposure in coal mines and combat coal worker pneumoconiosis. Empirical relationships and deterministic models for particular dust capture experiments have previously been devised to show the key parameters involved in airborne coal dust capture. Many of the results from these models show that the significant parameters related to airborne dust capture are water spray pressure, water quantity, water droplet size, relative water droplet-to-dust particle velocity, and total operating air pressure of the scrubber. However, many airborne dust capture efficiency relationships and models developed for particular experiments cannot be readily applied to forecast the dust collection efficiency of different spray and scrubber design configurations, which rely on several key dimensional engineering measures. This study examines engineering measures from previous water spray and wet scrubber experiments conducted by the U.S. National Institute for Occupational Safety and Health (NIOSH) and the U.S. Bureau of Mines (USBM) to develop empirical models for wet collection of airborne dusts. A dimensionless empirical model developed for predicting airborne dust capture efficiency of water sprays and wet scrubbers is presented.

Natriuretic response to renal medullary endothelin B receptor activation is impaired in Dahl-salt sensitive rats on a high-fat diet.

Renal medullary endothelin B receptors (ET(B)) mediate sodium excretion and blood pressure (BP) control. Several animal models of hypertension have impaired renal medullary ET(B) function. We found that 4-week high-caloric diet elevated systolic BP in Dahl salt-sensitive (Dahl S) rats (126+/-2 vs. 143+/-3 mm Hg, p<0.05). We hypothesized that renal medullary ET(B) function is dysfunctional in DS rats fed a high-caloric diet. We compared the diuretic and natriuretic response to intramedullary infusion of ET(B) agonist sarafotoxin 6c (S6c) in DS rats fed either a normal or high-caloric diet for 4 weeks. Urine was collected during intramedullary infusion of saline for baseline collection followed by intramedullary infusion of either saline or S6c. We first examined the ET(B) function in DS rats fed a normal diet. S6c increased urine flow (2.7+/-0.3 microl/min during baseline vs. 5.1+/-0.6 microl/min after S6c; p<0.05; n=5) and sodium excretion (0.28+/-0.05 vs. 0.81+/-0.17 micromol/min; p<0.05), suggesting that DS rats have renal medullary ET(B) function. However, DS rats fed a high-caloric diet displayed a significant increase in urine flow (2.7+/-0.4 vs. 4.2+/-0.4 microl/min, baseline vs. S6c infusion, respectively; p<0.05, n=6), but no significant change in sodium excretion in response to S6c (0.32+/-0.06 vs. 0.45+/-0.10 micromol/min). These data demonstrate that renal medullary ET(B) function is impaired in DS rats fed a high-caloric diet, which may be contributed to the elevation of blood pressure during high-caloric feeding in this model.

Generation of transgenic goats by pronuclear microinjection: a retrospective analysis of a commercial operation (1995-2012).

Production of transgenic founder goats involves introducing and stably integrating an engineered piece of DNA into the genome of the animal. At LFB USA, the ultimate use of these transgenic goats is for the production of recombinant human protein therapeutics in the milk of these dairy animals. The transgene or construct typically links a milk protein specific promoter sequence, the coding sequence for the gene of interest, and the necessary downstream regulatory sequences thereby directing expression of the recombinant protein in the milk during the lactation period. Over the time period indicated (1995-2012), pronuclear microinjection was used in a number of programs to insert transgenes into 18,120, 1- or 2- cell stage fertilized embryos. These embryos were transferred into 4180 synchronized recipient females with 1934 (47%) recipients becoming pregnant, 2594 offspring generated, and a 109 (4.2%) of those offspring determined to be transgenic. Even with new and improving genome editing tools now available, pronuclear microinjection is still the predominant and proven technology used in this commercial setting supporting regulatory filings and market authorizations when producing founder transgenic animals with large transgenes (> 10 kb) such as those necessary for directing monoclonal antibody production in milk.

Influence of continuous mining arrangements on respirable dust exposures.

In underground continuous mining operations, ventilation, water sprays and machine-mounted flooded-bed scrubbers are the primary means of controlling respirable dust exposures at the working face. Changes in mining arrangements - such as face ventilation configuration, orientation of crosscuts mined in relation to the section ventilation and equipment operator positioning - can have impacts on the ability of dust controls to reduce occupational respirable dust exposures. This study reports and analyzes dust concentrations measured by the Pittsburgh Mining Research Division for remote-controlled continuous mining machine operators as well as haulage operators at 10 U.S. underground mines. The results of these respirable dust surveys show that continuous miner exposures varied little with depth of cut but are significantly higher with exhaust ventilation. Haulage operators experienced elevated concentrations with blowing face ventilation. Elevated dust concentrations were observed for both continuous miner operators and haulage operators when working in crosscuts driven into or counter to the section airflow. Individual cuts are highlighted to demonstrate instances of minimal and excessive dust exposures attributable to particular mining configurations. These findings form the basis for recommendations for lowering face worker respirable dust exposures.

Use of information and communication technology amongst New Zealand dental students.

Although international studies have shown an increasing use of information and communication technology (ICT) amongst dental students, there are no published studies specific to New Zealand (NZ). The aim of this research was to identify device ownership and academic utilisation patterns amongst New Zealand dental students, including preferences and perceptions, and barriers to use. All currently enrolled dental students (322) were invited to complete a 15-item questionnaire. Data were statistically analysed in SPSS version 20.0. Qualitative data were analysed using a general inductive technique. The participation rate was 78.6% (N = 253 of 322). The majority of respondents personally owned laptop computers (98%) and smartphones (80.2%). A total of 10.8% of participants used a desktop computer everyday for academic purposes, whilst 78.7% used a laptop computer daily, and 54.7% a smartphone. New Zealand dental students demonstrated a high usage of ICT for their coursework with varied use of different online resources. The most frequently used online resources were search engines, social networking sites and lecture slides provided on Blackboard(®) . A high perceived value was placed on both audio podcasts and video podcasts despite the high value also placed on the traditional lectures. Although most participants (84.5%) felt that their ICT knowledge was adequate to meet academic requirements, a small number (1.6%) did not agree.

ET-1 increases reactive oxygen species following hypoxia and high-salt diet in the mouse glomerulus.

AIM: This study was designed to determine whether ET-1 derived from endothelial cells contributes to oxidative stress in the glomerulus of mice subjected to a high-salt diet and/or hypoxia. METHODS: C57BL6/J control mice or vascular endothelial cell ET-1 knockout (VEET KO) mice were subjected to 3-h exposure to hypoxia (8% O2) and/or 2 weeks of high-salt diet (4% NaCl) prior to metabolic cage assessment of renal function and isolation of glomeruli for the determination of reactive oxygen species (ROS). RESULTS: In control mice, hypoxia significantly increased urinary protein excretion during the initial 24 h, but only in animals on a high-salt diet. Hypoxia increased glomerular ET-1 mRNA expression in control, but not in vascular endothelial cell ET-1 knockout (VEET KO) mice. Under normoxic conditions, mice on a high-salt diet had approx. 150% higher glomerular ET-1 mRNA expression compared with a normal-salt diet (P < 0.05). High-salt diet administration significantly increased glomerular ROS production in flox control, but not in glomeruli isolated from VEET KO mice. In C57BL6/J mice, the ETA receptor-selective antagonist, ABT-627, significantly attenuated the increase in glomerular ROS production produced by high-salt diet. In addition, chronic infusion of C57BL6/J mice with a subpressor dose of ET-1 (osmotic pumps) significantly increased the levels of glomerular ROS that were prevented by ETA antagonist treatment. CONCLUSION: These data suggest that both hypoxia and a high-salt diet increase glomerular ROS production via endothelial-derived ET-1-ETA receptor activation and provide a potential mechanism for ET-1-induced nephropathy.

Survey of patient satisfaction after Doppler-guided transanal hemorrhoidal dearterialization performed in ambulatory settings.

BACKGROUND: Transanal hemorrhoidal dearterialization (THD) is a recently developed procedure to minimize postoperative pain from hemorrhoidectomy. This technique utilizes Doppler signals to aid ligation of hemorrhoidal arteries followed by mucopexy of redundant mucosa if needed. The aim of the present study was to assess patient satisfaction after THD. METHODS: This is a retrospective cohort study of patients who underwent THD at three different sites from April 2007 through October 2010. All procedures were performed in ambulatory settings according to protocol. Telephone surveys were conducted after a minimum of 1-month follow-up to assess patients' satisfaction on a scale of 1-10. Patients were asked whether the procedure had alleviated their symptoms. Patients were asked to recall duration of pain and time from surgery to return to work. RESULTS: Between April 2007 and October 2010, 216 patients with grade III-IV hemorrhoids underwent THD. There were 165 males and 61 females. Average age was 52.2 ± 14.2 years. All patients were discharged the same day after meeting ambulatory surgery center discharge criteria. Postoperative difficulty urinating occurred in 37 (17 %) patients, and six of them required temporary urinary catheterization. Transitory postoperative bleeding was reported by 38 (18 %) patients. Transitory incontinence to stool and flatus occurred in 18 (9 %) and 16 patients (8 %), respectively. Pelvic muscle spasms occurred in 21 (10 %) patients. Median follow-up was 23 months (range 1-42 months) with 143 (66 %) having at least 9 months between procedure and interview. Mean patient satisfaction was 8.5 ± 0.7 (on a scale of 1-10 with 10 being the best), and 91.5 % of patients felt the procedure had "helped" them. Average number of days with discomfort was 6.7 ± 2.1. Patients returned to work after an average of 10.3 ± 3.2 days. Our study is limited by lack of long-term follow-up and by retrospective complication assessment. CONCLUSIONS: Patient satisfaction with THD performed in ambulatory settings is high. Our data support performance of this procedure in an ambulatory setting.

ET-1 actions in the kidney: evidence for sex differences.

Hypertension and chronic kidney disease are more common in men than in premenopausal women at the same age. In animal models, females are relatively protected against genetic or pharmacological procedures that produce high blood pressure and renal injury. Overactivation or dysfunction of the endothelin (ET) system modulates the progression of hypertension or kidney diseases with the ET(A) receptor primarily mediating vasoconstriction, injury and anti-natriuresis, and ET(B) receptors having opposite effects. The purpose of this review is to examine the role of the ET system in the kidney with a focus on the inequality between the sexes associated with the susceptibility to and progression of hypertension and kidney diseases. In most animal models, males have higher renal ET-1 mRNA expression, greater ET(A) -mediated responses, including renal medullary vasoconstriction, and increased renal injury. These differences are reduced following gonadectomy suggesting a role for sex hormones, mainly testosterone. In contrast, females are relatively protected from high blood pressure and kidney damage via increased ET(B) versus ET(A) receptor function. Furthermore, ET(A) receptors may have a favourable effect on sodium excretion and reducing renal damage in females. In human studies, the genetic polymorphisms of the ET system are more associated with hypertension and renal injury in women. However, the knowledge of sex differences in the efficacy or adverse events of ET(A) antagonists in the treatment of hypertension and kidney disease is poorly described. Increased understanding how the ET system acts differently in the kidneys between sexes, especially with regard to receptor subtype function, could lead to better treatments for hypertension and renal disease. LINKED ARTICLES This article is part of a themed section on Endothelin. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.168.issue-1.

Combined consideration for decentralised non-potable water supply from local groundwater and nutrient load reduction in urban drainage.

Integrated analysis of land use change and its effect on catchment water balance allows the selection of appropriate water and land management options for new urban developments to minimise the environmental impacts of urbanisation. A process-based coupled surface water-groundwater model was developed for Southern River catchment (Perth, Western Australia) to investigate the effect of urban development on catchment water balance. It was shown that urbanisation of highly permeable flat catchments with shallow groundwater resulted in significant increase in net groundwater recharge. The increased recharge creates the opportunity to use local groundwater resources for non-potable water supply with the added advantage of reducing the total discharge from new urban developments. This minimises the environmental impacts of increased urbanisation, as higher discharge is often associated with greater nutrient loads to receiving environments. Through the used of water balance modelling it was demonstrated that there are both water and nutrient benefits from local groundwater use in terms of reduced nutrient exports to receiving waters and additional water resources for non-potable water supply.

Improved anticoagulant control in patients using home international normalized ratio testing and decision support provided through the Internet.

AIM: To compare anticoagulant control using self-testing and decision support provided via the internet with standard laboratory testing. METHODS: A prospective comparative study of 41 patients on long-term warfarin. All patients were monitored using a laboratory-based service for at least 12 months prior to changing to self-testing using a portable testing device and online decision support. The level of anticoagulant control was assessed using the time the international normalized ratio (INR) was within the therapeutic range (TTR), the proportion of INR results in range and the interval between tests. This was a non-inferiority study. RESULTS: There was no statistically significant difference between the two methods of anticoagulant control with a trend in favour of self-testing; the mean TTR was 72% vs 81%. However, a small cohort of patients with poor control (TTR 38%) during laboratory testing achieved a significant improvement (TTR 71%) using self-testing. The INR was above the therapeutic range for a similar time in both groups but below the range for a significantly shorter period during self-testing suggesting a lower risk of complication in this group. CONCLUSION: Self-testing with online computer decision support achieved anticoagulant control at least as good as laboratory management. Additional benefits of a home-based service make this an attractive option for selected patients.

Endothelin receptor A-specific stimulation of glomerular inflammation and injury in a streptozotocin-induced rat model of diabetes.

AIMS/HYPOTHESIS: Activation of endothelin receptor-A (ET(A)) increases glomerular permeability to albumin (P(alb)) and elevates pro-inflammatory markers in hyperglycaemic rats. METHODS: Male Sprague-Dawley rats were given streptozotocin (n = 32) or saline (sham; n = 32). Half of the animals in each group received the ET(A)-selective antagonist, ABT-627 (atrasentan; orally), beginning immediately after hyperglycaemia was confirmed. Glomeruli were isolated by sieving techniques and P(alb) determined from the change in glomerular volume induced by oncotic gradients of albumin. Glomerular nephrin levels were assessed by immunofluorescence, whereas urinary nephrin was measured by immunoassay. RESULTS: At 3 and 6 weeks after streptozotocin injection, proteinuria was significantly increased compared with sham controls and significantly reduced by ABT-627 treatment. P(alb) was also increased at 3 and 6 weeks post-streptozotocin. ABT-627 had no effect on P(alb) or protein excretion in sham control rats. In glomeruli isolated from hyperglycaemic rats, incubation with BQ-123, a selective ET(A) antagonist, reduced P(alb), whereas BQ-788, a selective endothelin receptor-B antagonist had no effect (n = 6 rats per group, 5-8 glomeruli per rat). Glomerular and plasma content of soluble intercellular adhesion molecule-1 and monocyte chemoattractant protein-1 were significantly increased 6 weeks after streptozotocin (ELISA). ABT-627 attenuated these increases. After 6 weeks of hyperglycaemia, glomerular nephrin content was decreased with a concurrent increase in urinary nephrin excretion. ABT-627 prevented glomerular nephrin loss in hyperglycaemic rats (n = 5-8 rats per group; eight groups). CONCLUSIONS/INTERPRETATION: These observations support the hypothesis that endothelin-1, via the ET(A) receptor, directly increases P(alb), possibly via nephrin loss, as well as early inflammation in the hyperglycaemic rat.

Species diversity and qualitative assessment of ground beetles (Coleoptera: Carabidae) in three riparian habitats.

In a 3-yr study involving saltcedar-free, saltcedar-infested, and burned habitats in a riparian area at Lake Meredith, TX, the number of carabid species collected, diversity indices, and indicator species varied significantly among habitats. A 3-yr average of 15, 14, and 24 carabid species were collected from the saltcedar-free, saltcedar-infested, and burned habitats, respectively. Values for species richness, Shannon's and Simpson's diversity indices, and evenness index for pooled data collected from 2005 to 2007 were higher in the burned habitat followed by the saltcedar-free habitat and the saltcedar-infested habitat. Within-year parameters across the three habitats generally followed the pooled data results with some variation. Nonmetric multidimensional scaling analyses clearly indicated groups of carabid species preferred specific habitats. Five species in the burned area had indicator species percentage values >50% (Agonum punctiforme, Agonum texanum, Brachinus alternans, Harpalus pensylvanicus, and Poecilus chalcites). In the saltcedar-infested and saltcedar-free habitats, only one species in each habitat had indicator species percentage values that exceeded 50%: Calathus opaculus and Cicindela punctulata punctulata, respectively.

Dynamic nucleotide mutation gradients and control region usage in squamate reptile mitochondrial genomes.

Gradients of nucleotide bias and substitution rates occur in vertebrate mitochondrial genomes due to the asymmetric nature of the replication process. The evolution of these gradients has previously been studied in detail in primates, but not in other vertebrate groups. From the primate study, the strengths of these gradients are known to evolve in ways that can substantially alter the substitution process, but it is unclear how rapidly they evolve over evolutionary time or how different they may be in different lineages or groups of vertebrates. Given the importance of mitochondrial genomes in phylogenetics and molecular evolutionary research, a better understanding of how asymmetric mitochondrial substitution gradients evolve would contribute key insights into how this gradient evolution may mislead evolutionary inferences, and how it may also be incorporated into new evolutionary models. Most snake mitochondrial genomes have an additional interesting feature, 2 nearly identical control regions, which vary among different species in the extent that they are used as origins of replication. Given the expanded sampling of complete snake genomes currently available, together with 2 additional snakes sequenced in this study, we reexamined gradient strength and CR usage in alethinophidian snakes as well as several lizards that possess dual CRs. Our results suggest that nucleotide substitution gradients (and corresponding nucleotide bias) and CR usage is highly labile over the approximately 200 m.y. of squamate evolution, and demonstrates greater overall variability than previously shown in primates. The evidence for the existence of such gradients, and their ability to evolve rapidly and converge among unrelated species suggests that gradient dynamics could easily mislead phylogenetic and molecular evolutionary inferences, and argues strongly that these dynamics should be incorporated into phylogenetic models.

Contrasting effects of eplerenone and spironolactone on adrenal cell steroidogenesis.

Spironolactone and eplerenone are widely used as mineralocorticoid antagonists. Spironolactone has several nonspecific actions including inhibition of androgen receptor and steroid hormone biosynthesis. While studies have shown that eplerenone does not exhibit nonspecific actions on androgen receptor, its effects on steroid hormone production have not been reported. Herein, the effects of eplerenone (0.1-30 microM) and spironolactone (0.1-30 microM) on steroid production were examined in human adrenocortical H295R cells. Spironolactone inhibited basal production of cortisol (91%) and aldosterone (53%). Treatment of H295R cells with angiotensin II (Ang II) for 24 h increased aldosterone production by 11-fold. Spironolactone inhibited Ang II stimulation of aldosterone production by 80%. Addition of pregnenolone increased aldosterone (9-fold) and cortisol (3-fold) production. Spironolactone inhibited pregnenolone metabolism to aldosterone (67%) and cortisol (74%). The inhibitory effects of spironolactone occurred at concentrations far higher than those needed to block mineralocorticoid receptor, suggesting an action directly on the enzymes involved in steroid production. In contrast, eplerenone did not inhibit basal, Ang II, forskolin, pregnenolone-stimulated cortisol, or aldosterone production. Together, these data demonstrate that opposed to spironolactone, pharmacologic concentrations of eplerenone do not inhibit adrenal cell aldosterone or cortisol production.

Endothelin(A) (ET(A)) and ET(B) receptor-mediated regulation of nitric oxide synthase 1 (NOS1) and NOS3 isoforms in the renal inner medulla.

AIM: Our laboratory and others have shown that endothelin (ET)-1 directly stimulates nitric oxide (NO) production in inner medullary collecting duct (IMCD) cells. The goal of this study was to determine which NO synthase (NOS) isoforms in IMCD are sensitive to ET-1, and the role of ET(A) and ET(B) receptor activation in vivo and in vitro. METHODS: NOS enzymatic activity and NOS isoform protein expression were examined in cultured IMCD-3 cells and isolated renal inner medulla. ET(B) receptor-deficient homozygous rats (sl/sl) have elevated levels of circulating ET-1 and lack a functional ET(B) signalling pathway in kidneys, and furthermore provides a unique model to study ET(A) receptor signalling in the renal inner medulla in vivo. RESULTS: Incubation of IMCD-3 cells with exogenous ET-1 (50 nm) resulted in ET(A)-dependent increased NOS1 protein expression in IMCD-3 cells with no effect on NOS2 or NOS3 expression. ET(B) receptor antagonism has no effect on NOS expression in IMCD-3 cells. Consistent with in vitro results, cytosolic NOS1 protein expression was significantly greater in the renal inner medulla of sl/sl rats compared with heterozygous (sl/+) controls, with no alteration in NOS3 expression. In contrast to protein expression data, NOS1- and NOS3-specific enzymatic activities decreased in the cytosolic fraction from the renal inner medulla of sl/sl compared with sl/+. CONCLUSION: These results provide evidence that both ET(A) and ET(B) receptors regulate NOS isoform activity in the renal inner medulla and specifically support the hypothesis that ET(A) receptor activation increases NOS1 expression.