Simultaneous Measurement of Muon Neutrino ν_{µ} Charged-Current Single π

Neutrino-induced charged-current single π^{+} production in the Δ(1232) resonance region is of considerable interest to accelerator-based neutrino oscillation experiments. In this Letter, high statistic differential cross sections are reported for the semiexclusive reaction ν_{µ}A→µ^{-}π^{+}+ nucleon(s) on scintillator, carbon, water, iron, and lead targets recorded by MINERvA using a wideband ν_{µ} beam with ⟨E_{ν}⟩≈6 GeV. Suppression of the cross section at low Q^{2} and enhancement of low T_{π} are observed in both light and heavy nuclear targets compared with phenomenological models used in current neutrino interaction generators. The cross sections per nucleon for iron and lead compared with CH across the kinematic variables probed are 0.8 and 0.5 respectively, a scaling which is also not predicted by current generators.

The variable associations between PFASs and biological aging by sex and reproductive stage in NHANES 1999-2018.

BACKGROUND: Per- and polyfluoroalkyl substances (PFASs) are endocrine disrupting chemicals that have myriad effects on human physiology. Estrogenic PFASs may influence biological aging by mimicking the activity of endogenous estrogens, which can decrease inflammation and oxidative stress and enhance telomerase activity. We hypothesized that PFAS exposure would be differentially associated with measures of biological aging based on biological sex and reproductive stage. METHODS: We analyzed associations between serum PFAS levels and measures of biological aging for pre- and postmenopausal women and men (n = 3193) using data from the 2003 to 2018 waves of the National Health and Nutrition Examination Survey. Examining PFASs both individually and in mixture models, we investigated four measures of clinical aging (Homeostatic Dysregulation, the Klemera-Doubal Method, Phenotypic Age Acceleration, and Allostatic Load), oxidative stress, and telomere length. RESULTS: PFOA and PFOS were negatively associated with Phenotypic Age Acceleration (e.g. decelerated aging) for men B = -0.22, 95% CI: -0.32, -0.12; B = -0.04, 95% CI: -0.06, -0.03) , premenopausal women (B = -0.58, 95% CI: -0.83, -0.32; B = -0.15, 95% CI: -0.20, -0.09), and postmenopausal women (B= -0.22, 95% CI: -0.43, -0.01; B = -0.05, 95% CI: -0.08, -0.02). In mixture models, we found net negative effects for Phenotypic Age Acceleration and Allostatic Load for men, premenopausal women, and postmenopausal women. We also found significant mixture effects for the antioxidants bilirubin and albumin among the three sample groups. We found no evidence to support effects on telomere length. DISCUSSION: Our findings suggest that PFAS exposure may be inversely associated with some measures of biological aging at the relatively low levels of exposure in this sample, regardless of reproductive stage and sex, which does not support our hypothesis. This research provides insights into how PFAS exposure may variably influence aging measures depending on the physiological process investigated.

'Flower of the body': menstrual experiences and needs of young adolescent women with cerebral palsy in Bangladesh, and their mothers providing menstrual support.

BACKGROUND: This study offers voice to young adolescent women with cerebral palsy (CP) in Bangladesh as they describe their menstrual experiences and needs, and their mothers providing menstrual support. METHOD: Semi-structured focus groups with adolescents with CP, and separately their mother. Data was analysed using a material discursive framework and drawing on feminist disability theory. Participants were recruited from the Bangladesh CP Register (BCPR); a population-based surveillance of children and adolescents with CP in rural Bangladesh. RESULTS: Participants were 45 women including 12 female adolescents with CP and 33 female caregivers. Participants reported a wide range of experiences and needs; menarche acted as a gateway to menstrual information although for some a discourse of silence prevailed due to exclusion from peer and familial networks. Menstruation was discursively constructed as a sign of 'female maturation' marked by an expectation of 'independence', required for acceptance into socially valued adult roles, and was positioned alongside increased vulnerability to sexual abuse. Young adolescent women with CP were expected to 'quietly endure' the material aspects of menstruation although unmanaged pain and distress were described. Mothers reported an imperative for meeting their adolescent's menstrual needs however this role was discursively positioned as 'painful', 'irritating' and 'shameful', in part due to an absence of affordable, functional menstrual resources. CONCLUSION: The findings of the present study provide motivation for disability services in Bangladesh to account for the menstrual needs of young adolescent women with CP within service delivery through strategies such as providing menstrual education and by embedding value in constructs such as 'interdependence'. Moreover, interventions focused on alleviating menstrual pain among young adolescent women with CP as well as those targeted to alleviate distress among mothers providing menstrual care are required. Finally, policy responses are required to ensure that 'inclusive development' considers the needs of menstruating women with disability.

Prospective validation of a novel renal activity index of lupus nephritis.

Objectives The renal activity index for lupus (RAIL) score was developed in children with lupus nephritis as a weighted sum of six urine biomarkers (UBMs) (neutrophil gelatinase-associated lipocalin, monocyte chemotactic protein 1, ceruloplasmin, adiponectin, hemopexin and kidney injury molecule 1) measured in a random urine sample. We aimed at prospectively validating the RAIL in adults with lupus nephritis. Methods Urine from 79 adults was collected at the time of kidney biopsy to assay the RAIL UBMs. Using receiver operating characteristic curve analysis, we evaluated the accuracy of the RAIL to discriminate high lupus nephritis activity status (National Institutes of Health activity index (NIH-AI) score >10), from low/moderate lupus nephritis activity status (NIH-AI score ≤10). Results In this mixed racial cohort, high lupus nephritis activity was present in 15 patients (19%), and 71% had proliferative lupus nephritis. Use of the identical RAIL algorithm developed in children resulted in only fair prediction of lupus nephritis activity status of adults (area under the receiver operating characteristic curve (AUC) 0.62). Alternative weightings of the six RAIL UBMs as suggested by logistic regression yielded excellent accuracy to predict lupus nephritis activity status (AUC 0.88). Accuracy of the model did not improve with adjustment of the UBMs for urine creatinine or albumin, and was little influenced by concurrent kidney damage. Conclusions The RAIL UBMs provide excellent prediction of lupus nephritis activity in adults. Age adaption of the RAIL is warranted to optimize its discriminative validity to predict high lupus nephritis activity status non-invasively.

An audit of the quality of online immunisation information available to Australian parents.

BACKGROUND: The Internet is increasingly a source of health information for parents, who use the Internet alongside health care providers for immunisation information. Concerns have been raised about the reliability of online immunisation information, however to date there has been no audit of the quality or quantity of what is available to Australian parents. The objective of this study was to address this gap by simulating a general online search for immunisation information, and assessing the quality and quantity of the web sites returned by the search. METHODS: We used Google trends to identify the most common immunisation search terms used in Australia. The ten most common terms were entered into five search engines and the first ten non-commercial results from each search collated. A quality assessment tool was developed using the World Health Organization Global Advisory Committee on Vaccine Safety (GACVS) criteria for assessing the quality of vaccine safety web sites, and used to assess and score the quality of the sites. RESULTS: Seven hundred web pages were identified, of which 514 were duplicates, leaving 186 pages from 115 web sites which were audited. Forty sites did not include human immunisation information, or presented personal opinion about individuals, and were not scored. Of the 75 sites quality scored, 65 (87%) were supportive of immunisation, while 10 (13%) were not supportive. The overall mean quality score was 57/100 (range 14/100 to 92/100). When stratified by pro and anti-vaccination stance, the average quality score for pro-vaccine sites was 61/100, while the average score for anti-vaccine sites was 30/100. Pro-vaccine information could be divided into three content groups: generalist overview with little detail; well-articulated and understandable detail; and lengthy and highly technical explanations. The main area found to be lacking in pro-vaccine sites was lack of transparent authorship. CONCLUSION: Our findings suggest a need for information which is easily found, transparently authored, well-referenced, and written in a way that is easily understood.

Australian Hajj pilgrims' knowledge, attitude and perception about Ebola, November 2014 to February 2015.

Upon return from Hajj 2014, 150 Australian pilgrims were interviewed about their understanding of the Ebola epidemic. Most (89%, 134/150) knew of the epidemic before travelling and 60% (80/134) of those knew Ebola transmits through body fluids. Pilgrims who received pre-travel health advice were more conscious of Ebola (69% vs 31%, p = 0.01) and adhered better to hand hygiene after touching an ill person (68% vs 31%, p < 0.01). Mass media was the main information source (78%).

Evidence for a prostate cancer susceptibility locus on the X chromosome.

Over 200,000 new prostate cancer cases are diagnosed in the United States each year, accounting for more than 35% of all cancer cases affecting men, and resulting in 40,000 deaths annually. Attempts to characterize genes predisposing to prostate cancer have been hampered by a high phenocopy rate, the late age of onset of the disease and, in the absence of distinguishing clinical features, the inability to stratify patients into subgroups relative to suspected genetic locus heterogeneity. We previously performed a genome-wide search for hereditary prostate cancer (HPC) genes, finding evidence of a prostate cancer susceptibility locus on chromosome 1 (termed HPC1; ref. 2). Here we present evidence for the location of a second prostate cancer susceptibility gene, which by heterogeneity estimates accounts for approximately 16% of HPC cases. This HPC locus resides on the X chromosome (Xq27-28), a finding consistent with results of previous population-based studies suggesting an X-linked mode of HPC inheritance. Linkage to Xq27-28 was observed in a combined study population of 360 prostate cancer families collected at four independent sites in North America, Finland and Sweden. A maximum two-point lod score of 4.60 was observed at DXS1113, theta=0.26, in the combined data set. Parametric multipoint and non-parametric analyses provided results consistent with the two-point analysis. Significant evidence for genetic locus heterogeneity was observed, with similar estimates of the proportion of linked families in each separate family collection. Genetic mapping of the locus represents an important initial step in the identification of an X-linked gene implicated in the aetiology of HPC.

Germline mutations in the ribonuclease L gene in families showing linkage with HPC1.

Although prostate cancer is the most common non-cutaneous malignancy diagnosed in men in the United States, little is known about inherited factors that influence its genetic predisposition. Here we report that germline mutations in the gene encoding 2'-5'-oligoadenylate(2-5A)-dependent RNase L (RNASEL) segregate in prostate cancer families that show linkage to the HPC1 (hereditary prostate cancer 1) region at 1q24-25 (ref. 9). We identified RNASEL by a positional cloning/candidate gene method, and show that a nonsense mutation and a mutation in an initiation codon of RNASEL segregate independently in two HPC1-linked families. Inactive RNASEL alleles are present at a low frequency in the general population. RNASEL regulates cell proliferation and apoptosis through the interferon-regulated 2-5A pathway and has been suggested to be a candidate tumor suppressor gene. We found that microdissected tumors with a germline mutation showed loss of heterozygosity and loss of RNase L protein, and that RNASEL activity was reduced in lymphoblasts from heterozyogous individuals compared with family members who were homozygous with respect to the wildtype allele. Thus, germline mutations in RNASEL may be of diagnostic value, and the 2-5A pathway might provide opportunities for developing therapies for those with prostate cancer.

A user-centered approach to developing a new tool measuring the behavioural and social drivers of vaccination.

BACKGROUND: Children around the world remain under-vaccinated for many reasons. To develop effective vaccine delivery programmes and monitor intervention impact, vaccine programme implementers need to understand reasons for under-vaccination within their local context. The World Health Organization (WHO) Working Group on the Behavioural and Social Drivers of Vaccination (BeSD) is developing standardised tools for assessing childhood vaccine acceptance and uptake that can be used across regions and countries. The tools will include: (1) a validated survey; (2) qualitative interview guides; and (3) corresponding user guidance. We report a user-centred needs assessment of key end-users of the BeSD tools. METHODS: Twenty qualitative interviews (Apr-Aug 2019) with purposively sampled vaccine programme managers, partners and stakeholders from UNICEF and WHO country and regional offices. The interviews assessed current systems, practices and challenges in data utilisation and reflections on how the BeSD tools might be optimised. Framework analysis was used to code the interviews. RESULTS: Regarding current practices, participants described a variety of settings, data systems, and frequencies of vaccination attitude measurement. They reported that the majority of data used is quantitative, and there is appetite for increased use of qualitative data. Capacity for conducting studies on social/behavioural drivers of vaccination was high in some jurisdictions and needed in others. Issues include barriers to collecting such data and variability in sources. Reflecting on the tools, participants described the need to explore the attitudes and practices of healthcare workers in addition to parents and caregivers. Participants were supportive of the proposed mixed-methods structure of the tools and training in their usage, and highlighted the need for balance between tool standardisation and flexibility to adapt locally. CONCLUSIONS: A user-centred approach in developing the BeSD tools has given valuable direction to their design, bringing the use of behavioural and social data to the heart of programme planning.

Midwives' attitudes, beliefs and concerns about childhood vaccination: A review of the global literature.

Vaccine hesitancy in industrialised countries is an area of concern. Health professionals play a significant role in parental vaccination decisions, however, to date the role of midwives has not been widely explored. This review sought to describe the attitudes and communication practices of midwives in developed countries towards childhood vaccines. Medline, Cinahl, PsychInfo, Embase and the grey literature were searched. Inclusion criteria were qualitative and quantitative studies reporting midwives' beliefs, attitudes and communication practices toward childhood vaccination. The search returned 366 articles, of which 359 were excluded by abstract. Two additional articles were identified from the grey literature and references, resulting in nine studies from five countries included in the review. Across the studies, the majority of midwives supported vaccination, although a spectrum of beliefs and concerns emerged. A minority expressed reservations about the scientific justification for vaccination, which focussed on what is not yet known rather than mistrust of current evidence. Most midwives felt that vaccines were safe; a minority were unsure, or believed they were unsafe. The majority of midwives agreed that childhood vaccines are necessary. Among those who expressed doubt, a commonly held opinion was that vaccine preventable diseases such as measles are relatively benign and didn't warrant vaccination against them. Finally, the midwifery model of care was shown to focus on providing individualised care, with parental choice being placed at a premium. The midwifery model care appears to differ in approach from others, possibly due to a difference in the underpinning philosophies. Research is needed to understand how midwives see vaccination, and why there appears to be a spectrum of views on the subject. This information will inform the development of resources tailored to the midwifery model of care, supporting midwives in advocating for childhood vaccination.

Vaccine decision-making begins in pregnancy: Correlation between vaccine concerns, intentions and maternal vaccination with subsequent childhood vaccine uptake.

INTRODUCTION: Maternal and childhood vaccine decision-making begins prenatally. Amongst pregnant Australian women we aimed to ascertain vaccine information received, maternal immunisation uptake and attitudes and concerns regarding childhood vaccination. We also aimed to determine any correlation between a) intentions and concerns regarding childhood vaccination, (b) concerns about pregnancy vaccination, (c) socioeconomic status (SES) and (d) uptake of influenza and pertussis vaccines during pregnancy and routine vaccines during childhood. METHODS: Women attending public antenatal clinics were recruited in three Australian states. Surveys were completed on iPads. Follow-up phone surveys were done three to six months post delivery, and infant vaccination status obtained via the Australian Childhood Immunisation Register (ACIR). RESULTS: Between October 2015 and March 2016, 975 (82%) of 1184 mothers consented and 406 (42%) agreed to a follow up survey, post delivery. First-time mothers (445; 49%) had significantly more vaccine concerns in pregnancy and only 73% had made a decision about childhood vaccination compared to 89% of mothers with existing children (p-value<0.001). 66% of mothers reported receiving enough information during pregnancy on childhood vaccination. In the post delivery survey, 46% and 82% of mothers reported receiving pregnancy influenza and pertussis vaccines respectively. The mother's degree of vaccine hesitancy and two attitudinal factors were correlated with vaccine uptake post delivery. There was no association between reported maternal vaccine uptake or SES and childhood vaccine uptake. CONCLUSION: First time mothers are more vaccine hesitant and undecided about childhood vaccination, and only two thirds of all mothers believed they received enough information during pregnancy. New interventions to improve both education and communication on childhood and maternal vaccines, delivered by midwives and obstetricians in the Australian public hospital system, may reduce vaccine hesitancy for all mothers in pregnancy and post delivery, particularly first-time mothers.

Managing toxicities associated with immune checkpoint inhibitors: consensus recommendations from the Society for Immunotherapy of Cancer (SITC) Toxicity Management Working Group.

Cancer immunotherapy has transformed the treatment of cancer. However, increasing use of immune-based therapies, including the widely used class of agents known as immune checkpoint inhibitors, has exposed a discrete group of immune-related adverse events (irAEs). Many of these are driven by the same immunologic mechanisms responsible for the drugs' therapeutic effects, namely blockade of inhibitory mechanisms that suppress the immune system and protect body tissues from an unconstrained acute or chronic immune response. Skin, gut, endocrine, lung and musculoskeletal irAEs are relatively common, whereas cardiovascular, hematologic, renal, neurologic and ophthalmologic irAEs occur much less frequently. The majority of irAEs are mild to moderate in severity; however, serious and occasionally life-threatening irAEs are reported in the literature, and treatment-related deaths occur in up to 2% of patients, varying by ICI. Immunotherapy-related irAEs typically have a delayed onset and prolonged duration compared to adverse events from chemotherapy, and effective management depends on early recognition and prompt intervention with immune suppression and/or immunomodulatory strategies. There is an urgent need for multidisciplinary guidance reflecting broad-based perspectives on how to recognize, report and manage organ-specific toxicities until evidence-based data are available to inform clinical decision-making. The Society for Immunotherapy of Cancer (SITC) established a multidisciplinary Toxicity Management Working Group, which met for a full-day workshop to develop recommendations to standardize management of irAEs. Here we present their consensus recommendations on managing toxicities associated with immune checkpoint inhibitor therapy.

Mobile Health Technology Can Objectively Capture Physical Activity (PA) Targets Among African-American Women Within Resource-Limited Communities-the Washington, D.C. Cardiovascular Health and Needs Assessment.

BACKGROUND: Little is understood about using mobile health (mHealth) technology to improve cardiovascular (CV) health among African-American women in resource-limited communities. METHODS: We conducted the Washington, D.C. CV Health and Needs Assessment in predominantly African-American churches in city wards 5, 7, and 8 with the lowest socioeconomic status based on community-based participatory research (CBPR) principles. The assessment measured CV health factors: body mass index (BMI), fasting blood glucose and cholesterol, blood pressure, fruit/vegetable (F/V) intake, physical activity (PA), and smoking. Participants were trained to use a PA monitoring wristband to measure 30 days of PA, wirelessly upload the PA data to hubs at the participating churches, and access their data from a church/home computer. CV health factors were compared across weight classes. RESULTS: Among females (N = 78; 99 % African-American; mean age = 59 years), 90 % had a BMI categorized as overweight/obese. Across weight classes, PA decreased and self-reported sedentary time (ST) increased (p ≤ 0.05). Diastolic blood pressure and glucose increased across weight classes (p ≤ 0.05); however, cholesterol, glucose, and BP were near intermediate CV health goals. CONCLUSIONS: Decreased PA and increased ST are potential community intervention targets for overweight and obese African-American women in resource-limited Washington D.C. areas. mHealth technology can assist in adapting CBPR intervention resources to improve PA for African-American women in resource-limited communities.

Genetic variation among 82 pharmacogenes: The PGRNseq data from the eMERGE network.

Genetic variation can affect drug response in multiple ways, although it remains unclear how rare genetic variants affect drug response. The electronic Medical Records and Genomics (eMERGE) Network, collaborating with the Pharmacogenomics Research Network, began eMERGE-PGx, a targeted sequencing study to assess genetic variation in 82 pharmacogenes critical for implementation of "precision medicine." The February 2015 eMERGE-PGx data release includes sequence-derived data from ∼5,000 clinical subjects. We present the variant frequency spectrum categorized by variant type, ancestry, and predicted function. We found 95.12% of genes have variants with a scaled Combined Annotation-Dependent Depletion score above 20, and 96.19% of all samples had one or more Clinical Pharmacogenetics Implementation Consortium Level A actionable variants. These data highlight the distribution and scope of genetic variation in relevant pharmacogenes, identifying challenges associated with implementing clinical sequencing for drug treatment at a broader level, underscoring the importance for multifaceted research in the execution of precision medicine.

An A-chain ricin immunotoxin targeted against rat class II major histocompatibility complex molecules. In vitro and in vivo effects.

Studies reported here have demonstrated that an antirat class II major histocompatibility complex molecule A-chain ricin immunotoxin could specifically remove, in a dose-dependent manner, the cells capable of stimulating the rat mixed lymphocyte reaction, an in vitro model of transplant rejection. It was further demonstrated that administration of a monoclonal antibody against class II major histocompatibility complex molecules to isolated rat pancreas grafts by hypothermic perfusion resulted in the targeting of cells bearing class II major histocompatibility complex molecules. But administration of the immunotoxin to isolated pancreases in a similar manner did not prolong their survival when allografted across a major histocompatibility barrier.

Thromboxane and prostacyclin synthesis in experimental pancreas transplantation. Changes in parenchymal and vascular prostanoids.

The principal causes of failure of a pancreas transplant are rejection and vascular thrombosis. There is an unusually high attrition rate for pancreas transplants, but study models have been difficult to develop. In a rat model that allows study of acute rejection to the exclusion of nonspecific effects of transplant surgery on the pancreas, in vitro synthesis of prostacyclin (PGI2) and thromboxane A2 (TXA2) by transplanted pancreas and the blood vessels transplanted with it was measured using an RIA for their stable hydrolysis products 6-keto-prostaglandin F1 alpha and thromboxane B2 (TXB2). TXB2 synthesis was significantly greater in allotransplanted pancreas than isotransplanted pancreas from the 5th day after transplantation. Rejection was complete in the allografted group 7-9 days after transplantation. 6-Keto-prostaglandin F1 alpha synthesis was similar in the pancreas for both allografts and isografts. Similar changes were seen in aorta, celiac artery, superior mesenteric artery, and portal vein transplanted with the pancreas. In the transplanted aorta, TXB2 was significantly greater in the allograft group from the third posttransplant day. A group of CsA-treated allografts sampled after 9 days had transplanted pancreatic parenchymal and vascular prostanoid synthesis in the isograft range. The changes in PGI2 and TXA2 synthesis that accompany cellular rejection may mediate vascular failure in rejecting pancreas transplants, and changes in PGI2 and TXA2 synthesis in blood vessels transplanted with the pancreas could promote early vascular thrombosis.

Cortical and vascular prostaglandin synthesis during renal allograft rejection in the rat.

Alterations in local prostacyclin and thromboxane synthesis could mediate the changes in vascular perfusion and platelet deposition in acutely rejecting renal allografts and prostaglandin E2 (PGE2) has been implicated in the regulation of the immune response. 6-Keto-prostaglandin F1 alpha (6 KetoPGF1 alpha), thromboxane B2 (TxB2) (the stable degradation products of prostacyclin and thromboxane A2 [TxA2], respectively) and PGE2 were measured in incubates of cortical slices taken from rat renal allografts or isografts one to seven days after transplantation. 6 KetoPGF1 alpha and TxB2 synthesis was also measured in incubates of blood vessels supplying and transplanted with the kidney in these animals. During the phase of cellular rejection (3-5 days), TxB2 synthesis was selectively elevated in allografted renal cortex, renal artery, renal vein, and abdominal aorta in comparison with isografted tissues. There was also a small but significant rise in cortical PGE2 synthesis at this time, but vascular and cortical 6 KetoPGF1 alpha production remained unchanged. Renal infarction, occurring 7 days after transplantation, was accompanied by a nonspecific rise in the synthesis of all three prostaglandins by renal cortical slices. Increased tissue TxA2 synthesis may contribute to local thrombosis and decreased graft perfusion during acute rejection, thereby potentiating graft destruction.

Nitric oxide-mediated modulation of the endothelin-1 signalling pathway in the human cardiovascular system.

1. We studied the ability of nitric oxide (NO) to physiologically antagonize endothelin-1 (ET-1) induced constrictions in human internal mammary artery (IMA). We also investigated the hypothesis that NO interacts directly with ET-receptor binding in human heart and aorta. 2. ET-1 potently contracted IMA (EC(50) 6.86 nM, 95% CI: 3.5 - 13.4 nM; n=12). The constrictor response to 10 nM ET-1 was fully reversed by the NO-donor diethylamine NONOate (DEA/NO; EC(50) 2.0 microM, 95% CI: 0.8 - 4.8 microM; n=5). The guanylate cyclase inhibitor ODQ (100 microM) reduced the response to DEA/NO but did not abolish it (E(MAX) 50.9+/-8.5% in the presence of ODQ; 113.0+/-8.4%, control). 3. The increase in cyclic GMP by 30 microM DEA/NO was abolished in the presence of 100 microM ODQ (n=6). 4. In saturation binding experiments the NO-donor Diethyltriamine NONOate (DETA/NO; 1 mM) caused a 90% reduction in maximum binding of [(125)I]-ET-1 in human heart, without affecting the affinity. This reduction in binding was abolished by haemoglobin. Pre-incubating either the radiolabel or the tissue with NO-donors did not reduce binding. A similar effect was observed in aortic smooth muscle. 5. We have shown that DEA/NO is able to reverse ET-1-induced contractions in the human vasculature. The binding studies suggest a direct interaction between NO and the ET receptor or receptor-ligand complex in human ventricular and aortic tissue. NO is released continuously in vivo, thus this apparent modification of ET-receptor binding may provide an additional mechanism by which NO counter-balances the effects of ET.

Physiological antagonism of endothelin-1 in human conductance and resistance coronary artery.

The ability of four endogenous vasodilators, nitric oxide (NO; 0.01 - 30 microM), atrial (ANP), brain (BNP) and C-type (CNP) natriuretic peptide (0.1 - 300 nM), to reverse endothelin-1 (ET-1; 10 nM) constrictions in human resistance and conductance coronary arteries (CA) in vitro was investigated. ET-1 (0.1 - 300 nM) constricted resistance CA more potently than conductance CA (P<0.05; EC(50) values 2.98 nM (95% CI: 1.49 - 5.95 nM and 8.58 (4.72 - 15.6 nM) respectively)). The NO-donor diethylamine NONOate fully reversed the ET-1 constriction in conductance CA (E(MAX) 127+/-9.16%), however only partial reversal was observed in resistance CA (E(MAX) 78.8+/-8.13; P<0.05). The soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (100 microM) reduced the maximum response to diethylamine NONOate to 76.9+/-14.4% in conductance CA (P<0.05), but had no effect on resistance CA (E(MAX) 77.2+/-18.4%). There was no difference between responses to ANP in conductance and resistance CA (EC(50) values 4.25 nM (0.84 - 21.4 nM) and 18.4 nM (2.92 - 116 nM), E(MAX) 53.1+/-14.7% and 48.6+/-11.8% respectively). BNP was a more potent vasodilator of conductance than resistance CA. In conductance CA the mean EC(50) value was 2.4 nM (0.74 - 7.75 nM), E(MAX) 54.5+/-14.9%. Concentration-response curves to BNP were incomplete in resistance CA. Concentration-response curves to CNP were incomplete in both conductance and resistance CA. The greater potency of ET-1 in resistance vessels may exacerbate the effects of increased circulating levels of the peptide in disease. Only NO could fully reverse ET-1 mediated constrictions in conductance CA, and none of the dilators tested could completely counteract constrictions in resistance CA.

Evidence that different mechanisms underlie smooth muscle relaxation to nitric oxide and nitric oxide donors in the rabbit isolated carotid artery.

1. The endothelium-dependent relaxants acetylcholine (ACh; 0.03-10 microM) and A23187 (0.03-10 microM), and nitric oxide (NO), applied either as authentic NO (0.01-10 microM) or as the NO donors 3-morpholino-sydnonimine (SIN-1; 0.1-10 microM) and S-nitroso-N-acetylpenicillamine (SNAP; 0.1-10 microM), each evoked concentration-dependent relaxation in phenylephrine stimulated (1-3 microM; mean contraction and depolarization, 45.8+/-5.3 mV and 31.5+/-3.3 mN; n=10) segments of rabbit isolated carotid artery. In each case, relaxation closely correlated with repolarization of the smooth muscle membrane potential and stimulated a maximal reversal of around 95% and 98% of the phenylephrine-induced depolarization and contraction, respectively. 2. In tissues stimulated with 30 mM KCl rather than phenylephrine, smooth muscle hyperpolarization and relaxation to ACh, A23187, authentic NO and the NO donors were dissociated. Whereas the hyperpolarization was reduced by 75-80% to around a total of 10 mV, relaxation was only inhibited by 35% (n=4-7 in each case; P<0.01). The responses which persisted to ACh and A23187 in the presence of 30 mM KCl were abolished by either the NO synthase inhibitor L-NG-nitroarginine methyl ester (L-NAME; 100 microM) or the inhibitor of soluble guanylyl cyclase 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10 microM; 10 min; n=4 in each case; P<0.01). 3. Exposure to ODQ significantly attenuated both repolarization and relaxation to ACh, A23187 and authentic NO, reducing the maximum changes in both membrane potential and tension to each relaxant to around 60% of control values (n=4 in each case; P<0.01). In contrast, ODQ almost completely inhibited repolarization and relaxation to SIN-1 and SNAP, reducing the maximum responses to around 8% in each case (n=3-5; P<0.01). 4. The potassium channel blockers glibenclamide (10 microM), iberiotoxin (100 nM) and apamin (50 nM), alone or in combination, had no significant effect on relaxation to ACh, A23187, authentic NO, or the NO donors SIN-1 and SNAP (n=4 in each case; P>0.05). Charybdotoxin (ChTX; 50 nM) almost abolished repolarization to ACh (n=4; P<0.01) and inhibited the maximum relaxation to ACh, A23187 and authentic NO each by 30% (n=4-8; P<0.01). Application of ODQ (10 microM; 10 min) abolished the ChTX-insensitive responses to ACh, A23187 and authentic NO (n=4 in each case; P<0.01 5. When the concentration of phenylephrine was reduced (to 0.3-0.5 microM) to ensure the level of smooth muscle contraction was the same as in the absence of potassium channel blocker, ChTX had no effect on the subsequent relaxation to SIN-1 (n=4; P>0.05). However, in the presence of tone induced by 1-3 microM phenylephrine (51.2+/-3.3 mN; n=4), ChTX significantly reduced relaxation to SIN-1 by nearly 50% (maximum relaxation 53.2+/-6.3%, n=4; P<0.01). 6. These data indicate that NO-evoked relaxation of the rabbit isolated carotid artery can be mediated by three distinct mechanisms: (a) a cyclic GMP-dependent, voltage-independent pathway, (b) cyclic GMP-mediated smooth muscle repolarization and (c) cyclic GMP-independent, ChTX-sensitive smooth muscle repolarization. Relaxation and repolarization to both authentic and endothelium-derived NO in this large conduit artery appear to be mediated by parallel cyclic GMP-dependent and -independent pathways. In contrast, relaxation to the NO-donors SIN-1 and SNAP appears to be mediated entirely via cyclic GMP-dependent mechanisms.