Publications by authors named "William Webster"

Background: Metagenomic next-generation sequencing (mNGS) testing identifies thousands of potential pathogens in a single blood test, though data on its real-world diagnostic utility are lacking.

Objectives: Determine the diagnostic utility of mNGS testing in practice and factors associated with high clinical utility.

Design: Retrospective cohort study of mNGS tests ordered from June 2018 through May 2020 at a community teaching hospital.

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Vinpocetine is a readily available nutritional supplement claimed to improve memory and weight loss. However, it blocks the kr current essential for cardiac action potential repolarisation and Ikr inhibition can cause "torsade de pointes" arrhythmias and sudden death. Moreover, Ikr blockers have exhibited teratogenic effects in reproductive toxicology studies, leading to increased birth defects and embryonic mortality.

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The way in which police officers interview sexual offence victims is pivotal to how their cases proceed through the criminal justice system (CJS). However, such interviews have previously been found to be lacking in overall quality, with some interviewers finding them technically difficult and stressful to conduct. In addition, victims often feel disbelieved, unsafe and/or uncomfortable during their police interview.

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Nausea and vomiting of pregnancy (NVP) is the most common medical complaint during pregnancy affecting up to 70% of pregnant women worldwide. Some antiemetic medications (AEM) (droperidol, domperidone, granisetron, metoclopramide and trifluoperazine) used to treat NVP have the unwanted side effect of hERG blockade. The hERG potassium channel is essential for normal heart rhythm in both the adult human and the human and rat embryo.

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Background: When the human heart begins its earliest contractions from day 21, it lacks a functional autonomic nerve supply. Instead, contractions are generated by regular calcium transients later augmented by the funny current (I ) produced by sinoatrial-like cells. This study examined effects of blocking these currents in the early rat embryonic heart.

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The potent hERG channel blocking drug ondansetron is used off-label for treatment of nausea and vomiting in early pregnancy. Some human epidemiological studies have associated ondansetron with fetal cardiovascular defects and orofacial clefts. This study investigated the effects of ondanestron on embryonic heart rhythm of gestational day (GD) 13 rat embryos in vitro and then integrated the results with published animal teratology, and animal and human pharmacokinetic studies to perform a risk evaluation.

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Ethylene glycol (EG) is a developmental toxicant in pregnant rats and mice. A suggested mechanism for this toxicity is that the EG metabolite, glycolic acid (GA), causes acidosis which may affect the embryonic heart rate (HR). This inhibition would cause periods of embryonic bradycardia and arrhythmia resulting in increased embryonic death and malformation in surviving embryos.

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Background: Tranylcypromine is a non-selective inhibitor of monamine oxidase which also inhibits the reuptake of norepinephrine. Spontaneous hypertensive reactions to the drug have been reported. In sheep tranylcypromine has been shown to cause a dose-dependent reduction in uterine blood flow.

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The aim of this study was to gain insight into whether the first trimester embryo could control its own heart rate (HR) in response to hypoxia. The gestational day 13 rat embryo is a good model for the human embryo at 5-6 weeks gestation, as the heart is comparable in development and, like the human embryo, has no functional autonomic nerve supply at this stage. Utilizing a whole-embryo culture technique, we examined the effects of different pharmacological agents on HR under normoxic (95% oxygen) and hypoxic (20% oxygen) conditions.

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Background: There are a wide range of drugs including antidepressants, anticonvulsants and antipsychotics that cause embryonic bradycardia in vitro but it is unknown if they have a similar effect in vivo. One way to verify whether these in vitro findings are replicated in vivo is by the use of ultrasound examination of dosed pregnant rats. We tested this by examining the effect of dofetilide on embryonic heart rate (HR) in vivo using ultrasound.

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Introduction: Although much reproductive toxicology research is performed in live animals there is increasing use of in vitro techniques primarily to identify potential hazards with human exposure. As many in vitro studies are undertaken using protein free media, the standard protocol is to compare the effect concentration determined in vitro with the predicted therapeutic free plasma concentration in humans. The aim of the present study was to test this rationale by comparing the effect of a small number of therapeutic drugs on heart rate of rodent embryos cultured in human sera or protein free serum.

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The Swedish Medical Product Agency (MPA) has listed erythromycin as a suggested human teratogen, causing cardiovascular malformations. It is further suggested that this may be a class effect of macrolide antibiotics. The proposed teratogenic mechanism is blockade of the human ether-á-go-go-related (hERG)/IKr current in the embryonic heart causing bradycardia and arrhythmia resulting in altered cardiac blood flow and/or embryonic hypoxia.

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During the organogenic period of development the cardiovascular system of the embryo fulfills several functions including delivery of oxygen and nutrients and a hemodynamic role necessary for cardiac morphogenesis, angiogenesis and hematopoiesis. It is expected that at each stage of embryonic development there is an ideal embryonic heart rate and contractility that maintains the optimal blood flow and pressure to fulfill these various functions. In vitro rat embryo culture studies have revealed that many therapeutic drugs (antiarrhythmics, antidepressants, antipsychotics and anticonvulsants), that may be taken during human pregnancy, cause a concentrationdependent slowing of the embryonic heart and irregular heart rate at higher concentrations.

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Introduction: The field of nuclear medicine is reliant on radionuclides for medical imaging procedures and radioimmunotherapy (RIT). The recent shut-downs of key radionuclide producers have highlighted the fragility of the current radionuclide supply network, however. To ensure that nuclear medicine can continue to grow, adding new diagnostic and therapy options to healthcare, novel and reliable production methods are required.

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In this study, we compared the effects of four ion channel blockers on rat embryonic heart function during the organogenic period from gestational day (GD) 10 to 15, to determine the changes in dependence on ion channels during rat cardiac development. Rat embryos in culture were exposed to either the human ether-á-go-go-related gene potassium channel blocker, dofetilide (400 nM); the sodium channel blocker, lidocaine (250 μM); the L-type calcium channel blocker, nifedipine (1.8 μM); or the multichannel blocker, phenytoin (200 μM).

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This study was undertaken to examine the effect on the rat embryonic heart of two experimental drugs (AZA and AZB) which are known to block the sodium channel Nav1.5, the hERG potassium channel and the l-type calcium channel. The sodium channel blockers bupivacaine, lidocaine, and the l-type calcium channel blocker nifedipine were used as reference substances.

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Background: An extended-release niacin product (Niaspan, Abbott Laboratories) was identified as a product with a less costly therapeutic alternative; a therapeutic product interchange was implemented.

Objective: To evaluate the efficacy and safety of a product therapeutic interchange from Niaspan to a controlled-release niacin product (Slo-Niacin, Upsher-Smith Laboratories) among patients at a large US Department of Veterans Affairs health care facility.

Methods: Patients with active prescriptions for Niaspan underwent a therapeutic product interchange to Slo-Niacin; following conversion of the product, the medical record for each patient was reviewed and pre- and postconversion clinical information and conversion details were transcribed into a database for subsequent analysis and study.

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Background: Dofetilide is an antiarrhythmic drug that blocks the cardiac repolarizing current IKr ((IKr, rapid component of the delayed rectifying potassium current). Previous studies have shown that (a) IKr is essential for normal cardiac function of the embryonic heart and (b) dofetilide is teratogenic in rodents. This study was undertaken to examine the mechanism by which dofetilide causes limb defects on gestational day 13 (GD 13) in the rat.

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A bottom-up and menu-based approach to embedding interprofessional education (IPE) into the curricula of more than 20 health profession programs at Dalhousie University is described. In addition to adopting an IPE graduation requirement and a common time for IPE activities, progress appears to have been facilitated by placing responsibility directly with the schools that own the curricula rather than with a central office for IPE.

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This study investigated the effects of a range of antidepressant drugs on the heart of gestation day 13 rat embryos in vitro. The general hypothesis was that the drugs would adversely affect the function of the embryonic heart since they all have some cardiac ion channel blocking activity in addition to their main pharmacological effect on neurotransmitters. The results showed that all the tested drugs caused bradycardia in a generally concentration-dependent manner.

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This study investigated the effects of a range of pharmaceutical drugs with ion channel-blocking activity on the heart of gestation day 13 rat embryos in vitro. The general hypothesis was that the blockade of the I(Kr)/hERG channel, that is highly important for the normal functioning of the embryonic rat heart, would cause bradycardia and arrhythmia. Concomitant blockade of other channels was expected to modify the effects of hERG blockade.

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TRAF6, a crucial adaptor molecule in innate and adaptive immunity, contains three distinct functional domains. The C-terminal TRAF domain facilitates oligomerization and sequence-specific interaction with receptors or other adaptor proteins. In conjunction with the dimeric E2 enzyme Ubc13-Uev1A, the N-terminal RING domain of TRAF6 functions as an E3 ubiquitin (Ub) ligase that facilitates its own site-specific ubiquitination through the generation of a Lys-63-linked poly-Ub chain.

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Background: The acardiac human fetus represents an accident of monozygotic twinning or higher multiple births due to an artery-to-artery and a vein-to-vein anastomosis in the monochorial placenta. Blood returning to the placenta through the umbilical artery of a normal cotwin is directed into the umbilical artery of the acardiac twin such that blood reaching the cranial end of the embryo is likely to be poorly oxygenated resulting in a number of structural defects including oral clefts. Although retrograde perfusion as a cause of hypoxia is unique to the acardiac fetus, there is ample evidence from animal studies that hypoxia is associated with facial clefting.

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Drugs blocking the potassium current IKr, either as an intended pharmacologic effect (eg antiarrhythmics dofetilide and almokalant) or as an unwanted side-effect (eg antihistamine astemizole, propulsive drug cisapride, antidepressive drugs and macrolide antibiotics) are potential human teratogens. It is the contention of this paper that the existing repeat dose regimen used in teratology studies to fulfil regulatory requirements, does not properly identify the teratogenic risk of these drugs. Results from conventional studies for dofetilide and almokalant showed high rates of postimplantation embryonic death with few malformed fetuses.

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