Intimate Partner Violence, Animal Maltreatment, and Barriers to Safety for Survivors with Companion Animals and Livestock: Findings From a Qualitative Study

This article examines the co-occurrence of violence against women and violence against animals based on interviews with 15 survivors in Saskatchewan, Canada. The qualitative data reveal complex dynamics of the human-animal bond for victims/survivors. Insufficient social supports exacerbate barriers for leaving relationships with animals when experiencing intimate partner violence; nonetheless, the participants perceived animals as crucial to their well-being. Care of horses and livestock is further complicated by financial issues and difficulty evacuating large animals. Survivors emphasized the need for social programs to assist survivors who care for companion animals and large animals.Content warning: This article contains descriptions of violence and abuse toward companion animals, horses, and livestock, as well as examples of animals being killed.

Potentially Psychologically Traumatic Event Exposure Histories of new Royal Canadian Mounted Police Cadets

OBJECTIVE

Royal Canadian Mounted Police (RCMP) report extremely frequent and varied exposures to potentially psychologically traumatic events (PPTEs). While occupational exposures to PPTEs may be one explanation for the symptoms of mental disorders prevalent among serving RCMP, exposures occurring prior to service may also play a role. The objective of the current study was to provide estimates of lifetime PPTE exposures among RCMP cadets in training and assess for associations with mental disorders or sociodemographic variables.

METHODS

RCMP cadets (n  =  772; 72.0% male) beginning the Cadet Training Program (CTP) completed a survey assessing self-reported PPTE exposures as measured by the Life Events Checklist for the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition-Extended. Binomial tests were conducted to compare the current results to previously collected data from the general population, a diverse sample of public safety personnel (PSP) and serving RCMP.

RESULTS

Cadets reported statistically significantly fewer PPTE exposures for all PPTE types than serving RCMP (all p's < 0.001) and PSP (all p's < 0.001) but more PPTE exposures for all PPTE types than the general population (all p's < 0.001). Cadets also endorsed fewer PPTE types (6.00  ±  4.47) than serving RCMP (11.64  ±  3.40; p < 0.001) and other PSP (11.08  ±  3.23) but more types than the general population (2.31  ±  2.33; p < 0.001). Participants who reported being exposed to any PPTE type reported the exposures occurred 1-5 times (29.1% of participants), 6-10 times (18.3%) or 10  +  times (43.1%) before starting the CTP. Several PPTE types were associated with positive screens for one or more mental disorders. There were associations between PPTE types and increased odds of screening positive for post-traumatic stress disorder (PTSD), major depressive disorder (MDD), generalized anxiety disorder (GAD) and social anxiety disorder (SAD) (all p's < 0.05). Serious transport accident (11.1%), physical assault (9.5%) and sudden accidental death (8.4%) were the PPTEs most identified as the worst event, and all were associated with positive screens for one or more mental disorders.

CONCLUSION

The current results provide the first information describing PPTE histories of cadets, evidencing exposure frequencies and types much higher than the general population. PPTE exposures may have contributed to the cadet's vocational choices. The current results support the growing evidence that PPTEs can be associated with diverse mental disorders; however, the results also suggest cadets may be uncommonly resilient, based on how few screened positive for mental disorders, despite reporting higher frequencies of PPTE exposures prior to CTP than the general population.

Suicidal Ideation, Planning, and Attempts Among new Royal Canadian Mounted Police Cadets

BACKGROUND

Royal Canadian Mounted Police (RCMP) report diverse occupational stressors and repeated exposures to potentially psychologically traumatic events, which may increase the odds of screening positive for a mental disorder, and increase the risk of death by suicide. The current study was designed to provide prevalence information regarding suicidal behaviours (i.e., ideation, planning, attempts) and assess for sociodemographic differences among cadets at the start of the RCMP Cadet Training Program (CTP).

METHOD

Cadets (n = 736, 74.0% male) were administered the structured Mini International Neuropsychiatric Interview by a mental health clinician or a supervised clinical psychologist trainee. The interview includes an assessment of past month suicidal ideation, planning, attempts and lifetime suicide attempts.

RESULTS

Within 1 month of starting the CTP, a small percentage of cadets reported past month suicidal ideation (1.6%) and no cadets reported any suicidal planning (0%) or attempts (0%). Lifetime suicide attempts were reported by (1.5%) of cadets.

CONCLUSIONS

The current results provide the first information describing the prevalence of suicidal ideation, planning, and attempts among RCMP cadets starting the CTP. The estimates of suicidal behaviours appear lower than the general population and lower than reports from serving RCMP. Higher prevalence estimates of suicidal behaviours reported by serving RCMP, relative to lower estimates among cadets starting the CTP in the current study, may be related to age, cumulative experiences or protracted exposures to operational and organizational stressors, rather than insufficient screening of recruits.

Mental Health of Royal Canadian Mounted Police at the Start of the Cadet Training Program

OBJECTIVE

Serving Royal Canadian Mounted Police (RCMP) have screened positive for one or more mental disorders based on self-reported symptoms with substantial prevalence (i.e., 50.2%). Mental health challenges for military and paramilitary populations have historically been attributed to insufficient recruit screening; however, cadet mental health when starting the Cadet Training Program (CTP) was unknown. Our objective was to estimate RCMP Cadet mental health when starting the CTP and test for sociodemographic differences.

METHOD

Cadets starting the CTP completed a survey assessing self-reported mental health symptoms (n = 772, 72.0% male) and a clinical interview (n = 736, 74.4% male) with a clinician or supervised trainee using the Mini-International Neuropsychiatric Interview to assess current and past mental health.

RESULTS

The percentage of participants screening positive for one or more current mental disorders based on self-reported symptoms (15.0%) was higher than the diagnostic prevalence for the general population (10.1%); however, based on clinical interviews, participants were less likely to screen positive for any current mental disorder (6.3%) than the general population. Participants were also less likely to screen positive for any past mental disorder based on self-report (3.9%) and clinical interviews (12.5%) than the general population (33.1%). Females were more likely to score higher than males (all ps<.01; Cohen's ds .23 to .32) on several self-report mental disorder symptom measures.

CONCLUSIONS

The current results are the first to describe RCMP cadet mental health when starting the CTP. The data evidenced a lower prevalence of anxiety, depressive, and trauma-related mental disorders than the general population based on clinical interviews, contrasting notions that more rigorous mental health screening would reduce the high prevalence of mental disorders among serving RCMP. Instead, protecting RCMP mental health may require ongoing efforts to mitigate operational and organizational stressors.

Putative risk and resiliency factors among Royal Canadian Mounted Police cadets

Objective

Mental health disorders are prevalent among active-duty Royal Canadian Mounted Police (RCMP) officers. The current study was designed to assess whether RCMP cadets commencing the Cadet Training Program are inherently at greater risk of developing mental health challenges by statistically comparing cadet putative risk and resiliency scores to scores from young adult populations. The study was also designed to assess for sociodemographic differences in putative risk and resiliency variables among RCMP cadets in order to facilitate future comparisons.

Methods

Cadets (n = 772; 72.2% men) completed self-report measures of several putative risk variables (i.e., anxiety sensitivity, fear of negative evaluation, pain anxiety, illness and injury sensitivity, intolerance of uncertainty, and state anger) and resiliency. Scores were statistically compared to samples from Canadian, American, Australian, and European young adult populations.

Results

Cadets had statistically significantly lower scores on all putative risk variables and statistically significantly higher resiliency scores compared to the young adult populations. In the cadet sample, there were statistically significant differences in putative risk and resiliency variables across gender and sex.

Conclusion

Cadets’ significantly lower scores on putative risk variables and higher scores on resiliency suggest that they may be psychologically strong; as such, it may be that the nature of police work, as opposed to inherent individual differences in risk and resiliency, accounts for active-duty RCMP officers’ comparatively higher prevalence of mental health disorders over time.

Clinical Trial Registration: ClinicalTrials.gov, Identifier NCT05527509.

Examining mental health knowledge, stigma, and service use intentions among Royal Canadian Mounted Police cadets

Background

Royal Canadian Mounted Police (RCMP) officers experience an elevated risk for mental health disorders due to inherent work-related exposures to potentially psychologically traumatic events and occupational stressors. RCMP officers also report high levels of stigma and low levels of intentions to seek mental health services. In contrast, very little is known about the levels of mental health knowledge and stigma of RCMP cadets starting the Cadet Training Program (CTP). The current study was designed to: (1) obtain baseline levels of mental health knowledge, stigma against peers in the workplace, and service use intentions in RCMP cadets; (2) determine the relationship among mental health knowledge, stigma against peers in the workplace, and service use intentions among RCMP cadets; (3) examine differences across sociodemographic characteristics; and (4) compare cadets to a sample of previously surveyed serving RCMP.

Methods

Participants were RCMP cadets (n = 772) starting the 26-week CTP. Cadets completed questionnaires assessing mental health knowledge, stigma against coworkers with mental health challenges, and mental health service use intentions.

Results

RCMP cadets reported statistically significantly lower levels of mental health knowledge (d = 0.233) and stigma (d = 0.127), and higher service use intentions (d = 0.148) than serving RCMP (all ps < 0.001). Female cadets reported statistically significantly higher scores on mental health knowledge and service use and lower scores on stigma compared to male cadets. Mental health knowledge and service use intentions were statistically significantly positively associated. For the total sample, stigma was inversely statistically significantly associated with mental health knowledge and service use intentions.

Conclusion

The current results indicate that higher levels of mental health knowledge were associated with lower stigma and higher intention to use professional mental health services. Differences between cadets and serving RCMP highlight the need for regular ongoing training starting from the CTP, designed to reduce stigma and increase mental health knowledge. Differences between male and female cadets suggest differential barriers to help-seeking behaviors. The current results provide a baseline to monitor cadet mental health knowledge and service use intentions and stigma as they progress throughout their careers.

Assessing the impact of the Royal Canadian Mounted Police (RCMP) protocol and Emotional Resilience Skills Training (ERST) among diverse public safety personnel

BACKGROUND

Public safety personnel (PSP; e.g., border services personnel, correctional workers, firefighters, paramedics, police, public safety communicators) are frequently exposed to potentially psychologically traumatic events. Such events contribute to substantial and growing challenges from posttraumatic stress injuries (PTSIs), including but not limited to posttraumatic stress disorder.

METHODS

The current protocol paper describes the PSP PTSI Study (i.e., design, measures, materials, hypotheses, planned analyses, expected implications, and limitations), which was originally designed to evaluate an evidence-informed, proactive system of mental health assessment and training among Royal Canadian Mounted Police for delivery among diverse PSP (i.e., firefighters, municipal police, paramedics, public safety communicators). Specifically, the PSP PTSI Study will: (1) adapt, implement, and assess the impact of a system for ongoing (i.e., annual, monthly, daily) evidence-based assessments; (2) evaluate associations between demographic variables and PTSI; (3) longitudinally assess individual differences associated with PTSI; and, (4) assess the impact of providing diverse PSP with a tailored version of the Emotional Resilience Skills Training originally developed for the Royal Canadian Mounted Police in mitigating PTSIs based on the Unified Protocol for the Transdiagnostic Treatment of Emotional Disorders. Participants are assessed pre- and post-training, and then at a follow-up 1-year after training. The assessments include clinical interviews, self-report surveys including brief daily and monthly assessments, and daily biometric data. The current protocol paper also describes participant recruitment and developments to date.

DISCUSSION

The PSP PTSI Study is an opportunity to implement, test, and improve a set of evidence-based tools and training as part of an evidence-informed solution to protect PSP mental health. The current protocol paper provides details to inform and support translation of the PSP PTSI Study results as well as informing and supporting replication efforts by other researchers.

TRIAL REGISTRATION

Hypotheses Registration: aspredicted.org, #90136. Registered 7 March 2022-Prospectively registered.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05530642. Registered 1 September 2022-Retrospectively registered. The subsequent PSP PTSI Study results are expected to benefit the mental health of all participants and, ultimately, all PSP.

The Royal Canadian Mounted Police (RCMP) Study: protocol for a prospective investigation of mental health risk and resilience factors

The Royal Canadian Mounted Police (RCMP), like all public safety personnel (PSP), are frequently exposed to potentially psychologically traumatic events that contribute to posttraumatic stress injuries (PTSI). Addressing PTSI is impeded by the limited available research. In this protocol paper, we describe the RCMP Study, part of the concerted efforts by the RCMP to reduce PTSI by improving access to evidence-based assessments, treatments and training as well as participant recruitment and RCMP Study developments to date. The RCMP Study has been designed to (1) develop, deploy and assess the impact of a system for ongoing annual, monthly and daily evidence-based assessments; (2) evaluate associations between demographic variables and PTSI; (3) longitudinally assess individual differences associated with PTSI; (4) augment the RCMP Cadet Training Program with skills to proactively mitigate PTSI; and (5) assess the impact of the augmented training condition (ATC) versus the standard training condition (STC). Participants in the STC (n = 480) and ATC (n = 480) are assessed before and after training and annually for 5 years on their deployment date; they also complete brief monthly and daily surveys. The RCMP Study results are expected to benefit the mental health of all participants, RCMP and PSP by reducing PTSI among all who serve.

Peer Support for Public Safety Personnel in Canada: Towards a Typology

Public safety personnel (PSP) are frequently exposed to potentially psychologically traumatic events (PPTEs) which can impact mental health. To help mitigate the negative effects of PPTEs, PSP commonly rely on peer support. Peer support generally refers to a wide variety of mental health resources that offer social or emotional assistance to a peer, and in some cases professional assistance. Despite the use of and demand for peer support, there is relatively little empirical evidence regarding effectiveness. The evidence gaps regarding peer support effectiveness may be due, in part, to inadequate guidelines and standards of practice that are publicly supported by a consensus among peer support providers. The current study was designed to explore the current conceptualization and implementation of peer support among Canadian PSP using a document analysis. The results indicate that peer support can be conceptualized via three models (i.e., peer-enabled, peer-led, peer-partnership) and implemented via two delivery methods (i.e., program, service). The research team proposed a novel diagram towards a typology of peer support to highlight the diversity in peer support conceptualization and implementation and provide a foundation for the development of mutually agreed-upon language and a shared framework. Overall, the current study can help inform peer support resources within and beyond PSP communities.

Evaluation of Before Operational Stress: A Program to Support Mental Health and Proactive Psychological Protection in Public Safety Personnel

Public safety personnel (PSP; e.g., communications officials, corrections workers, firefighters, paramedics, and police officers) are at risk of developing mental health problems due to experiencing potentially psychologically traumatic events during their career. Research examining evidence-based treatments for psychological injuries resulting from operational duties (also known as operational stress injuries) has not yielded robust results that would indicate ongoing interventions as the best solution for managing PSP mental health injuries; as such, proactive psychological interventions designed to bolster resilience are being considered potentially beneficial for mitigating the impact of occupational stress on PSP. Despite the growing popularity of resilience programs, most are delivered in a single session after an event deemed particularly problematic with no follow-up. Longer interventions may better support sustained resiliency, mitigate the impact of operational stress, and increase positive PSP workplace outcomes. The current article introduces the Before Operational Stress (BOS) program, which was designed for delivery early in a PSP career to enhance self-awareness and healthy relationships. The year-long program is derived from cognitive behavior therapy and group therapeutic techniques to meet program objectives. The current BOS program evaluation demonstrated small, statistically significant improvements in symptoms of PTSD, quality of life, stigma, and perceived social support from baseline (Time 1) to 6 months (Time 4). There were also non-significant improvements observed in symptoms of depression, anxiety, stress, alcohol use, as well as in emotional regulation and resilience. Qualitative results indicated participants positively perceived the BOS program, with participants reporting specific improvements in self-awareness, avoidant behaviors, and relationships with family and colleagues. The BOS program content (e.g., functional disconnection and functional reconnection) and processes (e.g., psychoeducation within a supportive learning structure; mutually empowering group interactions) appear unique relative to other PSP resilience programs, with promising initial results in support of PSP mental health. Recommendations for future research and program development are provided.

"Suck It Up, Buttercup": Understanding and Overcoming Gender Disparities in Policing

Women police officers report elevated symptoms of mental disorders when compared to men police officers. Researchers have indicated that the occupational experience of policing differs greatly among men and women. Indeed, police culture is characterized by hegemonic masculinity, which appears to negatively impact both men and women. The current study examined the contrast between the experiences of men and women police officers. Police officers (n = 17; 9 women) in Saskatchewan participated in semi-structured interviews. Thematic network analysis identified themes related to the experience of policing for both men and women police officers. There were six organizing themes identified in relation to the global theme of Gendered Experiences: (1) Discrimination; (2) Sexual Harassment; (3) Motherhood and Parental Leave; (4) Identity; (5) Stereotypically Feminine Attributes; and (6) Hegemonic Masculinity. Pervasive gender norms appear detrimental for both men and women police officers, as well as the communities they serve. The current results, coupled with the emerging disposition for progress expressed by police services, offer opportunities to develop tailored and focused interventions and policies to support police officers.

Echocardiographic RV-E/e' for predicting right atrial pressure: a review

Right atrial pressure (RAP) is a key cardiac parameter of diagnostic and prognostic significance, yet current two-dimensional echocardiographic methods are inadequate for the accurate estimation of this haemodynamic marker. Right-heart trans-tricuspid Doppler and tissue Doppler echocardiographic techniques can be combined to calculate the right ventricular (RV) E/e′ ratio – a reflection of RV filling pressure which is a surrogate of RAP. A systematic search was undertaken which found seventeen articles that compared invasively measured RAP with RV-E/e′ estimated RAP. Results commonly concerned pulmonary hypertension or advanced heart failure/transplantation populations. Reported receiver operating characteristic analyses showed reasonable diagnostic ability of RV-E/e′ for estimating RAP in patients with coronary artery disease and RV systolic dysfunction. The diagnostic ability of RV-E/e′ was generally poor in studies of paediatrics, heart failure and mitral stenosis, whilst results were equivocal in other diseases. Bland–Altman analyses showed good accuracy but poor precision of RV-E/e′ for estimating RAP, but were limited by only being reported in seven out of seventeen articles. This suggests that RV-E/e′ may be useful at a population level but not at an individual level for clinical decision making. Very little evidence was found about how atrial fibrillation may affect the estimation of RAP from RV-E/e′, nor about the independent prognostic ability of RV-E/e′ . Recommended areas for future research concerning RV-E/e′ include; non-sinus rhythm, valvular heart disease, short and long term prognostic ability, and validation over a wide range of RAP.

Adsorption of Pb(II) ions from contaminated water by 1,2,3,4-butanetetracarboxylic acid-modified microcrystalline cellulose: Isotherms, kinetics, and thermodynamic studies

Microcrystalline cellulose (MCC) has been utilized as an adsorbent material for the removal of Pb(II) ions from aqueous solution after treatment with 1,2,3,4-butanetetracarboxylic acid (BTCA) at elevated temperature to obtain MMCC. The resulting adsorbent was characterized for point of zero point charge (pHZPC), estimation of carboxyl content, Fourier transform infrared spectroscopy (FT-IR), scan electron microscopy (SEM), and textural properties, including surface area, and subsequently utilized for the removal of Pb(II) ions from aqueous solution. The adsorption process was probed by investigating the effect of adsorbent dose, pH of solution, temperature, agitation time, and Pb(II) ion concentration. The results showed successful functionalization of MCC using BTCA, significantly improved the binding properties of the adsorbent towards Pb(II) ions. Isothermal adsorption data was analyzed using Langmuir, Freundlich and Temkin models, evaluated via nonlinear regression analysis. The maximum adsorption capacity was found to be 1155 mg/g (at pH 5 and 30 °C) from Langmuir theory, and appears independent of surface area. The Freundlich model was found to provide the best fit and the constant n was determined to be 2.69, indicating that adsorption of Pb(II) ions onto MMCC is favorable. Kinetic modelling showed good agreement for the pseudo-second order kinetic model, supporting the theory that chemisorption is involved in the adsorption process, which is promoted by a high density of active sites. Thermodynamic analysis showed that the adsorption of Pb(II) ions onto MMCC was endothermic and nonspontaneous; hence, MMCC offers an effective method of Pb(II) ion removal from aqueous solutions, with potential for water remediation processes.

Imaging aortic valve calcification: significance, approach and implications

Aortic stenosis is the most prevalent valvular heart disease worldwide, and rates are increasing with the growing and more elderly population. Although the precise mechanisms that underpin aortic valve stenosis are incompletely understood, pathological valvular calcification has emerged as a key instigator in mediating the biomechanical stiffening that can lead to symptoms, the need for aortic valve replacement, and death if left untreated. Here, we review the currently understood processes leading to aortic valve calcification, summarise the contemporary imaging assessments of valve calcification, and highlight how these might improve patient care and accelerate our pathological understanding and the development of an effective medical therapy.

Prioritizing health leadership capabilities in Canada: Testing LEADS in a Caring Environment

This article is the first major empirical test of LEADS in a Caring Environment, the principal leadership capability framework in Canada. The results rank the perceived salience of leadership attributes, given time and budget constraints, while implementing a major organization reform in the Saskatchewan health system. The results also indicate important differences between self-assessed leadership behaviours versus observed behaviours in other leaders that may reflect participants' expectations of managers with designated authority.

Hydrogen Adsorption on Functionalized Nanoporous Activated Carbons

There is considerable interest in hydrogen adsorption on carbon nanotubes and porous carbons as a method of storage for transport and related energy applications. This investigation has involved a systematic investigation of the role of functional groups and porous structure characteristics in determining the hydrogen adsorption characteristics of porous carbons. Suites of carbons were prepared with a wide range of nitrogen and oxygen contents and types of functional groups to investigate their effect on hydrogen adsorption. The porous structures of the carbons were characterized by nitrogen (77 K) and carbon dioxide (273 K) adsorption methods. Hydrogen adsorption isotherms were studied at 77 K and pressure up to 100 kPa. All the isotherms were Type I in the IUPAC classification scheme. Hydrogen isobars indicated that the adsorption of hydrogen is very temperature dependent with little or no hydrogen adsorption above 195 K. The isosteric enthalpies of adsorption at zero surface coverage were obtained using a virial equation, while the values at various surface coverages were obtained from the van't Hoff isochore. The values were in the range 3.9-5.2 kJ mol(-1) for the carbons studied. The thermodynamics of the adsorption process are discussed in relation to temperature limitations for hydrogen storage applications. The maximum amounts of hydrogen adsorbed correlated with the micropore volume obtained from extrapolation of the Dubinin-Radushkevich equation for carbon dioxide adsorption. Functional groups have a small detrimental effect on hydrogen adsorption, and this is related to decreased adsorbate-adsorbent and increased adsorbate-adsorbate interactions.

Adsorption dynamics of gases and vapors on the nanoporous metal organic framework material Ni2(4,4'-bipyridine)3(NO3)4: guest modification of host sorption behavior

This study combines measurements of the thermodynamics and kinetics of guest sorption with powder X-ray diffraction measurements of the nanoporous metal organic framework adsorbent (host) at different adsorptive (guest) loadings. The adsorption characteristics of nitrogen, argon, carbon dioxide, nitrous oxide and ethanol and methanol vapors on Ni2(4,4'-bipyridine)3(NO3)4 were studied over a range of temperatures as a function of pressure. Isotherm steps were observed for both carbon dioxide and nitrous oxide adsorption at approximately 10-20% of the total pore volume and at approximately 70% of total pore volume for methanol adsorption. The adsorption kinetics obey a linear driving force (LDF) mass transfer model for adsorption at low surface coverage. At high surface coverage, both methanol and ethanol adsorption follow a combined barrier resistance/diffusion model. The rates of adsorption in the region of both the carbon dioxide and methanol isotherm steps were significantly slower than those observed either before or after the step. X-ray diffraction studies at various methanol loadings showed that the host structure disordered initially but underwent a structural change in the region of the isotherm step. These isotherm steps are ascribed to discrete structural changes in the host adsorbent that are induced by adsorption on different sites. Isotherm steps were not observed for ethanol adsorption, which followed a Langmuir isotherm. Previous X-ray crystallography studies have shown that all the sites are equivalent for ethanol adsorption on Ni2(4,4'-bipyridine)3(NO3)4, with the host structure undergoing a scissoring motion and the space group remaining unchanged during adsorption. The activation energies and preexponential factors for methanol and ethanol adsorption were calculated for each pressure increment at which the linear driving force model was obeyed. There was a good correlation between activation energy and ln(preexponential factor), indicating a compensation effect. The results are discussed in terms of reversible adsorbate/adsorbent (guest/host) structural changes and interactions and the adsorption mechanism. The paper contains the first evidence of specific interactions between guests and functional groups leading to structural change in flexible porous coordination polymer frameworks.

A novel method for controlled and reversible long term compression of the umbilical cord in fetal sheep

1. In fetal sheep during late gestation the aims of the present study were to (1) develop a technique for inducing prolonged but reversible periods of controlled compression of the umbilical cord and (2) characterise the cardiovascular, endocrine and metabolic responses to this challenge. 2. Under 1-2 % halothane anaesthesia, 16 Welsh Mountain sheep fetuses were chronically instrumented at 118 +/- 2 days of gestation (term is ca 145 days) with an inflatable occluder cuff around the umbilical cord, amniotic and femoral vascular catheters and with transit-time flow probes around the contra-lateral femoral artery and an umbilical artery. At 125 days, umbilical blood flow was reduced by 30 % from a pre-determined 24 h baseline for 3 days by automated servo-controlled inflation of the occluder cuff (n = 8). The occluder was then deflated allowing return of umbilical blood flow to baseline. The remaining eight fetuses were used as sham-operated controls in which the occluder was not inflated throughout the protocol. Fetal cardiovascular variables were recorded at 8 s intervals and arterial blood samples taken for measurement of blood gases, glucose and lactate and plasma adrenaline, noradrenaline and vasopressin concentration throughout the study. 3. Automated servo-controlled inflation of the occluder cuff, programmed to reduce umbilical blood flow by 30 % from baseline, reduced umbilical blood flow by 30.2 +/- 1.7 %, with a coefficient of variation during compression of 6.5 +/- 1.1 %. Sustained partial compression of the umbilical cord produced falls in fetal arterial pH, P(a,O2), percentage O(2) saturation of haemoglobin, and hindlimb oxygen delivery, and increases in P(a,CO2), haemoglobin concentration, arterial blood oxygen carrying capacity and in blood glucose and lactate concentrations. While the reductions in P(a,O2), percentage saturation of haemoglobin and hindlimb oxygen delivery and the increase in P(a,CO2) were sustained throughout compression, the reduction in arterial pH and the increase in arterial oxygen carrying capacity had returned towards baseline values by 48 h compression. Fetal blood lactate concentrations reached a peak at 8 h of compression and, thereafter, were maintained at an elevated level relative to baseline. 4. Partial compression of the umbilical cord produced fetal hypertension, a reduction in femoral blood flow and, consequently, an increase in calculated fetal femoral vascular resistance for the duration of the challenge. In addition, the fall in heart rate measured in sham control fetuses by the end of the study, did not occur in cord-compressed fetuses. Cosinor analysis on 24 h rhythms of cardiovascular data indicated a significant increase in the amplitude of the 24 h rhythm in heart rate in cord-compressed fetuses relative to sham controls during the period of compression or sham-compression. Furthermore, cord compression led to an increase in fetal plasma noradrenaline, but not adrenaline and vasopressin concentrations relative to sham control fetuses. 5. In conclusion, a novel reversible method for controlled, long-term compression of the umbilical cord in sheep has been developed. The data show that sustained, partial compression of the umbilical cord produced moderate but sustained asphyxia, which resolved after the end of the compression period, and induced changes in fetal cardiovascular, endocrine and metabolic functions.

Purinergic contribution to circulatory, metabolic, and adrenergic responses to acute hypoxemia in fetal sheep

This study investigated the effects on femoral vascular resistance, blood glucose and lactate levels, and plasma catecholamine concentrations of fetal treatment with an adenosine receptor antagonist during acute hypoxemia in fetal sheep during late gestation. Under anesthesia, seven fetal sheep were instrumented between 117 and 118 days gestation (term is approximately 145 days) with vascular and amniotic catheters and an ultrasonic probe around a femoral artery. Six days after surgery, all fetuses were randomly subjected to a 3-h experiment consisting of 1 h of normoxia, 1 h of hypoxemia, and 1 h of recovery. This was done during either intravenous infusion of vehicle or the adenosine receptor antagonist [8-(p-sulfophenyl)-theophylline; 8-SPT] dissolved in vehicle. During vehicle infusion, all fetuses responded to hypoxemia with bradycardia, an increase in arterial blood pressure, and femoral vasoconstriction. Increases in blood glucose and lactate concentrations and in plasma epinephrine and norepinephrine concentrations also occurred in all fetuses during hypoxemia. Fetal treatment with 8-SPT markedly attenuated the bradycardic, hypertensive, vasoconstrictor, glycemic, and adrenergic responses to hypoxemia, but it did not affect the increase in blood lactate concentrations during hypoxemia. These data show that adenosine is involved in the mechanisms mediating fetal cardiovascular, metabolic, and adrenergic responses to hypoxemia in fetal sheep. Fetal treatment with 8-SPT mimics the effects of carotid sinus nerve section on fetal cardiovascular function during hypoxemia, suggesting a role for adenosine in mediating fetal cardiovascular chemoreflexes.

Plasma adrenocorticotropin and cortisol concentrations during acute hypoxemia after a reversible period of adverse intrauterine conditions in the ovine fetus during late gestation

The present study determined the pituitary-adrenal responses to acute hypoxemia after a period of reversible adverse intrauterine conditions produced by partial compression of the umbilical cord for 3 days in the sheep fetus during late gestation. At 118 +/- 2 days gestation (term is approximately 145 days), 12 sheep fetuses were instrumented under halothane anesthesia with an occluder cuff around the umbilical cord, amniotic and vascular catheters, and a transit-time flow probe around an umbilical artery. In 6 of the fetuses at 125 days, umbilical blood flow was reduced by about 30% from baseline for 3 days (UCC), after which the occluder was deflated. The remaining 6 fetuses acted as sham-operated controls in which the occluder was not inflated. All fetuses were then subsequently subjected to 2 periods of acute hypoxemia, elicited by reducing the maternal inspired fraction of oxygen (FiO(2)) at 2 +/- 1 and 5 +/- 2 days after the end of cord compression or sham compression. In addition, 4 fetuses from each group were subjected to an ACTH challenge 1-2 days after the final episode of acute hypoxemia. Maternal and fetal arterial blood samples were taken at appropriate intervals during cord compression, acute hypoxemia, and ACTH challenge for analyses of blood gases, pH, and plasma ACTH and cortisol concentrations. Partial compression of the umbilical cord produced reversible mild fetal asphyxia, a transient increase in fetal plasma ACTH, and a progressive increase in fetal plasma cortisol. At 5 +/- 2 days after the end of compression, despite similar blood gas status between the groups, basal plasma cortisol, but not ACTH, concentrations were significantly greater in compressed fetuses relative to sham controls. However, this dissociation did not affect a similar increment in fetal plasma ACTH and cortisol concentrations during acute hypoxemia or in the fetal plasma cortisol response to the ACTH challenge in either group. An increase in adrenocortical mass occurred in fetuses preexposed to partial compression of the umbilical cord relative to sham controls. The data suggest that fetal exposure to a reversible period of adverse intrauterine conditions produced by partial compression of the umbilical cord does not affect the magnitude of the fetal hypothalamic-pituitary-adrenal axis response to subsequent acute hypoxemia, but it leads to resetting of basal hypothalamic-pituitary-adrenal axis function in the fetus. The mechanism for this resetting may include an increase in adrenocortical steroidogenic synthetic capacity, but it is not due to a change in adrenocortical sensitivity to ACTH. Inappropriate fetal glucocorticoid exposure after reversible periods of adverse intrauterine conditions has important implications for fetal and postnatal development.

Neuropeptide Y in the sheep fetus: effects of acute hypoxemia and dexamethasone during late gestation

Plasma concentrations of neuropeptide Y (NPY) were measured in pregnant ewes and their fetuses under basal conditions and in response to acute hypoxemia during late gestation. The effects of fetal treatment with dexamethasone on these NPY responses were also examined. Under general anesthesia, 10 Welsh Mountain ewes and their fetuses were chronically instrumented between 117-120 days gestation (dGA; term is approximately 145 dGA) with vascular and amniotic catheters, and an ultrasonic probe around a femoral artery of each fetus. At 124 dGA, five fetuses were continuously infused i.v. with dexamethasone for 48 h at a rate of 1.73 +/- 0.16 microg x kg(-1) x h(-1) while the remaining five fetuses received vehicle at the same rate. At 126 dGA, 45 h from the onset of either infusion, 1 h of materno-fetal hypoxemia was induced by reducing maternal FiO2. During normoxia, maternal plasma NPY concentrations were three times those measured in fetal plasma in both groups. During hypoxemia, PaO2 fell to similar levels in the control and dexamethasone-treated groups in both mothers and fetuses. In control animals, there was a significant increase in the NPY concentration in fetal, but not maternal, plasma during hypoxemia. Fetal treatment with dexamethasone significantly enhanced the fetal NPY response to acute hypoxemia but had no effects on basal NPY levels in the fetal or maternal plasma or on the maternal response to acute hypoxemia. These data show: 1) differences between the maternal and fetal plasma NPY response to maternal inhalation hypoxia; 2) that NPY may play a role in mediating fetal defense responses to acute hypoxemia; and 3) that fetal exposure to glucocorticoids modifies the fetal plasma NPY response to acute hypoxemia.

Low doses of dexamethasone suppress pituitary-adrenal function but augment the glycemic response to acute hypoxemia in fetal sheep during late gestation

Despite the widespread use of antenatal glucocorticoid therapy in obstetric practice, little is known about the effects of synthetic glucocorticoids on the fetal capacity to respond to episodes of acute hypoxemia, such as may occur during labor and delivery. This study investigated the effects of prolonged fetal exposure to low concentrations of dexamethasone on the fetal ACTH, cortisol, and glycemic responses to an episode of acute hypoxemia during the period of dexamethasone treatment in sheep. At 118 d of gestation (term is approximately 145 d), 11 fetal sheep had catheters implanted under halothane anesthesia. From 124 d, five fetuses were infused i.v. continuously with dexamethasone (1.80 +/- 0.15 microg x kg(-1) x h(-1) in 0.9% saline at 0.5 mL/h) for 48 h, and the other six fetuses received saline solution i.v. at the same rate. At 45 h of infusion, acute hypoxemia was induced in all fetuses for 1 h by reducing the maternal inspired fraction of oxygen. During glucocorticoid treatment, fetal plasma dexamethasone concentrations increased to 3.9 +/- 0.2 nM by 24 h and remained elevated for the rest of the infusion period. During hypoxemia, a similar fall in fetal arterial PO2 occurred in both saline-infused and dexamethasone-treated fetuses. In control fetuses, significant increases in plasma ACTH and cortisol concentrations and in blood glucose concentrations occurred during hypoxemia. Dexamethasone treatment prevented the increases in fetal plasma ACTH and cortisol, and augmented the blood glucose response, induced by hypoxemia. These data indicate that prolonged fetal exposure to low concentrations of dexamethasone suppresses pituitary-adrenal function, but augments the glycemic response, to acute hypoxemia in fetal sheep during late gestation.

A comparison of the effects of intravenous tramadol, codeine, and morphine on gastric emptying in human volunteers

We compared the effects of i.v. tramadol (1.25 mg/kg), codeine (1 mg/kg), morphine (0.125 mg/kg), and saline on gastric emptying in 10 healthy human volunteers using a double-blind, randomized, cross-over design. Subjects received one treatment at each of four sessions, 2 wk apart. Gastric emptying was studied using the paracetamol absorption test. There were significant differences when comparing all treatments for concentration-time data (P = 0.002), peak serum paracetamol concentrations (Cmax; P < 0.001), times at Cmax (Tmax; P = 0.003), and areas under the curves from Time 0 to 360 min (AUC(0-360); P = 0.049). Morphine profoundly inhibited gastric emptying. Tramadol had measurable but statistically insignificant inhibitory effects on gastric emptying compared with saline (mean +/- SEM: Cmax 22.4 +/- 2.2 vs 26.8 +/- 2.5 mg/L [P = 0.19], Tmax 33 +/- 5.4 vs 19.5 +/- 2.3 min [P = 0.054] for tramadol versus saline, respectively). Compared with morphine, the Cmax (P < 0.01), Tmax, and AUC(0-360) (P < 0.05) values for tramadol were significantly different. The Tmax value for codeine (63.3 +/- 11.7) was greater than that for tramadol (P = 0.034). We conclude that tramadol has a measurable but smaller inhibitory effect on gastric emptying compared with other opioids.

IMPLICATIONS

We compared the effect of tramadol, an unconventional opioid painkiller, on stomach emptying with that of codeine and morphine in a human volunteer study. Tramadol had a measurable but smaller effect and may have clinical and economic advantages in acute pain management compared with conventional painkillers.

Influence of a changed care environment on bacterial colonization of burn wounds

This study investigated the influence of a conditioned care environment per se on bacterial colonization of burn wounds. Two cohorts of burn patients were treated in the successive years 1992 and 1993, the first group in a (permanent) purpose-designed unit and the second in wards of traditional 'open' design, during renovation of the unit. Patients who were admitted to the permanent and temporary units numbered 224 and 231 respectively, the groups being similar in features that generally influence the course and outcome of burn injuries. The principles and practice of treatment by the burn care team remained the same in both years. No significant difference in wound colonization rates was found between the two groups. We conclude that while the other known advantages of managing burn patients in purpose-designed units remain valid, a conditioned care environment per se does not influence bacterial colonization rates of burn wounds.

Glutaraldehyde concentration in the sterilization of endoscopes

Controversy over appropriate disinfection of endoscopes continues with the most commonly utilized solution in Australian hospitals, despite concern over its efficacy, being 1% glutaraldehyde (AIDAL). Review of the in-use concentrations of glutaraldehyde at Princess Alexandra Hospital has documented a significant dilutional effect in 1% glutaraldehyde by gastrointestinal endoscopes. Each hospital should determine the minimum in-use concentration acceptable for any given disinfecting solution and any given range of endoscopes. Once this level is reached, a solution change should routinely occur. Such decisions can only be made by regularly monitoring in-use concentrations of disinfectants.

Structure-function analysis of the vitamin B12 receptor of Escherichia coli by means of informational suppression

We describe a genetic analysis of the vitamin B12 receptor of Escherichia coli. Through the use of informational suppression, we have been able to generate a family of receptor variants, each identical save for a single, known substitution (Ser, Gln, Lys, Tyr, Leu, Cys, Phe) at a known site. We have studied 22 different mutants, 14 in detail, distributed throughout the length of the btuB gene. Most amino acid substitutions have a pleiotropic effect with respect to all ligands tested, the two colicins E1 and E3, the T5-like bacteriophage BF23, and vitamin B12. (The dramatic effect of a single amino acid substitution is also well exemplified by the G142A missense change which renders the receptor completely non-functional.) In some instances, however, we have been able to modify a subset of receptor functions (viz. Q62, Q150 and Q299 and the response to phage BF23). These data are summarized on a two-dimensional folding model for the BtuB protein in the outer membrane (devised using both amphipathic beta-strand analysis and sequence conservation amongst the TonB-dependent receptors). In addition, we report that the extreme C-terminus of BtuB is vital for receptor localization and provide evidence for it being a membrane-spanning beta-sheet with residue L588 situated on its hydrophobic surface. Two of the C-terminal btuB mutations are located within the region of overlap with the recently identified dga (murl) gene.

Investigation of the regulation of the Escherichia coli btuB gene using operon fusions

Operon fusions were isolated between Mu dX (lac CmR ApR) and btuB, the gene encoding the multivalent vitamin B12 outer membrane receptor. Using these fusions, vitamin B12-mediated repression of btuB in Escherichia coli was demonstrated. Mutations in metH, metE and ompR as well as exogenous methionine, membrane pertubants, high osmolar conditions and temperature had no major effect on the expression of the btuB gene.