Association of Alcohol Consumption With CD4 Recovery After Antiretroviral Therapy Initiation in St. Petersburg, Russia

BACKGROUND

Delayed CD4 recovery after initiating antiretroviral therapy (ART) is a novel potential mechanism by which alcohol consumption leads to increased morbidity and mortality in people with HIV. We hypothesized that alcohol consumption at ART initiation is associated with slower CD4 recovery.

METHODS

We retrospectively analyzed 2 pooled longitudinal alcohol/HIV cohorts (2014-2019) in St. Petersburg, Russia. Eligible participants initiated the first ART during parent studies; had alcohol consumption assessed by the blood biomarker, phosphatidylethanol (PEth), at the last research visit before ART initiation; and had ≥1 CD4 count measurement before and after initiating ART. Participants were stratified by low, moderate, and high PEth (<8, 8-80, and >80 ng/mL, respectively). We used random-effects piecewise linear regression models to estimate CD4 recovery, defined as CD4 count change per 30 days after ART initiation, by the alcohol group.

RESULTS

Of 60 eligible participants, median age was 34 years and 28% were female. The median pre-ART PEth in the low, moderate, and high PEth groups were <8, 23, and 232 ng/mL, respectively. After starting ART, the CD4 count increased by 13.60 cells/mm3/mo (95% CI: 0.33 to 26.87) with low PEth, 0.93 cells/mm3/mo (95% CI: -6.18 to 8.04) with moderate PEth, and 2.33 cells/mm3/mo (95% CI: -3.44 to 8.09) with high PEth.

CONCLUSIONS

Among Russians with HIV, we observed faster CD4 recovery after ART initiation in those with low alcohol consumption compared with those with moderate and high alcohol consumption, as assessed by PEth. This analysis provides further evidence for the possible value of alcohol reduction interventions for people with HIV who are initiating ART.

Comparing COVID-19-related Morbidity and Mortality Between Patients With and Without Substance Use Disorders: A Retrospective Cohort Study

Objectives:

People with substance use disorders (SUD) are suggested to have higher risk of hospitalization, intubation, or death from coronavirus disease 2019 (COVID-19), although data are mixed. Little is known about other COVID-19-related complications in this group. We compared morbidity and mortality among individuals with and without SUD who were admitted to an urban safety net hospital with COVID-19 early in the pandemic, contemporaneous to other published studies on this subject.

Methods:

We performed a retrospective study of patients ⩾18 years old admitted with COVID-19 from March 16th to April 8th, 2020. SUD included alcohol, opioid, cocaine, amphetamine, and benzodiazepine use disorders and was identified using diagnostic codes, free text clinical documentation, and urine drug screens. The primary outcome was inpatient mortality. Secondary outcomes included clinical complications (eg, secondary infections, venous thromboembolism) and resource utilization (eg, mechanical ventilation, length of stay). We used multivariable regression to assess the relationship between SUD and mortality.

Results:

Of 409 patients, the mean age was 56 years and 13.7% had SUD. Those with SUD were more likely to be male, have experienced homelessness, have pulmonary disease or hepatitis C, or use tobacco or cannabis. After multivariable analysis, SUD was not associated with mortality (aOR 1.03; 95% CI, 0.31-3.10). Secondary outcomes were also similar between groups.

Conclusions:

Our findings suggest that persons with and without SUD have similar COVID-19-related outcomes. Previously reported increased COVID-19 complications may be from medical comorbidities.

Laboratory test trends within 72 hours of hospital admission associated with death among COVID-19 patients

Early identification of patients at risk for severe coronavirus disease 2019 (COVID-19) is crucial for appropriate triage and determination of need for closer monitoring. Few studies have examined laboratory trends in COVID-19 infection and sought to quantify the degree to which laboratory values affect mortality. We conducted a retrospective cohort (n = 407) study of hospitalized patients with COVID-19 early in the course of the pandemic, from March 16th to April 8th, 2020 and compared baseline to repeat laboratory testing 72 hours into admission. The primary outcome was death. We found that rises of 25 mg/L C-reactive protein, 50 units/L lactate dehydrogenase, and 100 ng/mL ferritin were associated with 23%, 28%, and 1% increased odds of death, respectively. In contrast, changes in fibrinogen, D-dimer, white blood cell count, and creatinine in the first few days of hospital admission were not associated with mortality. These quantitative findings may assist clinicians in determining the risk of potential clinical decline in patients with COVID-19 and influence early management.

Factors associated with inpatient complications among patients with obesity and COVID-19 at an urban safety-net hospital: A retrospective cohort study

Objective

Obesity increases morbidity and mortality from Coronavirus disease 2019 (COVID-19). This study characterized inpatient complications among patients with obesity and COVID-19-including myocardial infarction, renal failure requiring dialysis, stroke, secondary bacterial infection, and venous thromboembolism-and identified factors associated with developing at least one inpatient complication at a safety-net hospital with a diverse cohort.

Methods

A retrospective review was performed of all patients admitted for ≥3 days with COVID-19 between 16 March 2020, and 8 April 2020. Logistic regression identified factors associated with developing at least one COVID-19-related complication among patients with obesity (body mass index ≥30 kg/m2).

Results

374 patients were included; 53.7% were classified as having obesity, 43.9% identified as Black, and 38.5% identified as Latino or Hispanic. Obesity was not associated with having at least one inpatient complication on multivariable analysis, but increased age (aOR 1.02, [95% CI 1.01-1.04], p = 0.010) and obstructive sleep apnea (aOR 2.25, [1.08-4.85], p = 0.034) were associated with this outcome.

Conclusions

Obesity was not associated with specified inpatient complications among patients with COVID-19 admitted to a health system caring for diverse patients. Future studies should incorporate larger cohorts and reflect newer treatment protocols.

Genomic epidemiology of the first two waves of SARS-CoV-2 in Canada

Tracking the emergence and spread of SARS-CoV-2 lineages using phylogenetics has proven critical to inform the timing and stringency of COVID-19 public health interventions. We investigated the effectiveness of international travel restrictions at reducing SARS-CoV-2 importations and transmission in Canada in the first two waves of 2020 and early 2021. Maximum likelihood phylogenetic trees were used to infer viruses' geographic origins, enabling identification of 2263 (95% confidence interval: 2159-2366) introductions, including 680 (658-703) Canadian sublineages, which are international introductions resulting in sampled Canadian descendants, and 1582 (1501-1663) singletons, introductions with no sampled descendants. Of the sublineages seeded during the first wave, 49% (46-52%) originated from the USA and were primarily introduced into Quebec (39%) and Ontario (36%), while in the second wave, the USA was still the predominant source (43%), alongside a larger contribution from India (16%) and the UK (7%). Following implementation of restrictions on the entry of foreign nationals on 21 March 2020, importations declined from 58.5 (50.4-66.5) sublineages per week to 10.3-fold (8.3-15.0) lower within 4 weeks. Despite the drastic reduction in viral importations following travel restrictions, newly seeded sublineages in summer and fall 2020 contributed to the persistence of COVID-19 cases in the second wave, highlighting the importance of sustained interventions to reduce transmission. Importations rebounded further in November, bringing newly emergent variants of concern (VOCs). By the end of February 2021, there had been an estimated 30 (19-41) B.1.1.7 sublineages imported into Canada, which increasingly displaced previously circulating sublineages by the end of the second wave.Although viral importations are nearly inevitable when global prevalence is high, with fewer importations there are fewer opportunities for novel variants to spark outbreaks or outcompete previously circulating lineages.

Phylogenetic prioritization of HIV-1 transmission clusters with viral lineage-level diversification rates

Background and objectives

Public health officials faced with a large number of transmission clusters require a rapid, scalable and unbiased way to prioritize distribution of limited resources to maximize benefits. We hypothesize that transmission cluster prioritization based on phylogenetically derived lineage-level diversification rates will perform as well as or better than commonly used growth-based prioritization measures, without need for historical data or subjective interpretation.

Methodology

9822 HIV pol sequences collected during routine drug resistance genotyping were used alongside simulated sequence data to infer sets of phylogenetic transmission clusters via patristic distance threshold. Prioritized clusters inferred from empirical data were compared to those prioritized by the current public health protocols. Prioritization of simulated clusters was evaluated based on correlation of a given prioritization measure with future cluster growth, as well as the number of direct downstream transmissions from cluster members.

Results

Empirical data suggest diversification rate-based measures perform comparably to growth-based measures in recreating public heath prioritization choices. However, unbiased simulated data reveals phylogenetic diversification rate-based measures perform better in predicting future cluster growth relative to growth-based measures, particularly long-term growth. Diversification rate-based measures also display advantages over growth-based measures in highlighting groups with greater future transmission events compared to random groups of the same size. Furthermore, diversification rate measures were notably more robust to effects of decreased sampling proportion.

Conclusions and implications

Our findings indicate diversification rate-based measures frequently outperform growth-based measures in predicting future cluster growth and offer several additional advantages beneficial to optimizing the public health prioritization process.

333. Comparing COVID-19-related Morbidity and Mortality between Patients with and without Substance Use Disorder: A Retrospective Cohort Study

Background

Early data suggest that people with substance use disorder (SUD) who develop coronavirus disease 2019 (COVID-19) have increased intubation and mortality rates when compared to those without SUD. Information on other COVID-19-related complications in this population is limited. We evaluated COVID-19 outcomes in patients with and without SUD.

Methods

We created a retrospective cohort of patients with COVID-19 admitted to an urban safety net hospital from 3/16/2020 to 4/8/2020. Inclusion criteria were admission with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 and age greater than 18 years. SUD included alcohol use disorder or heavy alcohol use as defined by the National Institute on Alcohol Abuse and Alcoholism, use of cocaine, non-prescribed opioids or amphetamines. Primary outcome was inpatient mortality. Secondary outcomes were clinical complications (intubation, secondary infections, renal failure, venous thromboembolism, stroke, hepatitis, myocardial infarct, multisystem organ failure) and resource utilization (length of stay, intensive care unit [ICU] admission, ICU days, readmission). We used multivariable regression to assess factors associated with mortality and length of stay, and univariate analyses for other outcomes.

Results

Of 409 included patients, 70 (17.1%) had SUD. Those with SUD were more likely to be male and have pulmonary disease or hepatitis C. There were no differences in other comorbidities, mean age or race/ethnicity. After multivariable analysis, SUD was not associated with mortality (aOR 1.60; 95% CI, 0.60-3.81). Similarly baseline oxygenation defined as the ratio of oxygen saturation to fraction of inspired oxygen (aOR 1.57; 0.11-13.0) and administration of immunomodulatory therapy (tocilizumab, sarilumab or anakinra) (aOR 1.41; 0.65-3.01) did not affect mortality. In contrast, age (aOR 1.06; 1.03-1.09), sex (aOR 2.30; 1.04-5.47) and obstructive sleep apnea (aOR 4.07; 1.64-9.66) were associated with mortality. We did not find any associations with secondary outcomes.

Conclusion

Our findings suggest that substance use alone may not increase COVID-19 adverse outcomes. Future studies should evaluate these results in the current period of improved COVID-19 therapy.

Disclosures

All Authors: No reported disclosures

Concordance of HIV transmission risk factors elucidated using viral diversification rate and phylogenetic clustering

Background and objectives

Although HIV sequence clustering is routinely used to identify subpopulations experiencing elevated transmission, it over-simplifies transmission dynamics and is sensitive to methodology. Complementarily, viral diversification rates can be used to approximate historical transmission rates. Here, we investigated the concordance and sensitivity of HIV transmission risk factors identified by phylogenetic clustering, viral diversification rate, changes in viral diversification rate and a combined approach.

Methodology

Viral sequences from 9848 people living with HIV in British Columbia, Canada, sampled between 1996 and February 2019, were used to infer phylogenetic trees, from which clusters were identified and viral diversification rates of each tip were calculated. Factors associated with heightened transmission risk were compared across models of cluster membership, viral diversification rate, changes in diversification rate, and viral diversification rate among clusters.

Results

Viruses within larger clusters had higher diversification rates and lower changes in diversification rate than those within smaller clusters; however, rates within individual clusters, independent of size, varied widely. Risk factors for both cluster membership and elevated viral diversification rate included being male, young, a resident of health authority E, previous injection drug use, previous hepatitis C virus infection or a high recent viral load. In a sensitivity analysis, models based on cluster membership had wider confidence intervals and lower concordance of significant effects than viral diversification rate for lower sampling rates.

Conclusions and implications

Viral diversification rate complements phylogenetic clustering, offering a means of evaluating transmission dynamics to guide provision of treatment and prevention services.

Lay Summary

Understanding HIV transmission dynamics within clusters can help prioritize public health resource allocation. We compared socio-demographic and clinical risk factors associated with phylogenetic cluster membership and viral diversification rate, a historical branching rate, in order to assess their relative concordance and sampling sensitivity.

Fundamental Identifiability Limits in Molecular Epidemiology

Viral phylogenies provide crucial information on the spread of infectious diseases, and many studies fit mathematical models to phylogenetic data to estimate epidemiological parameters such as the effective reproduction ratio (Re) over time. Such phylodynamic inferences often complement or even substitute for conventional surveillance data, particularly when sampling is poor or delayed. It remains generally unknown, however, how robust phylodynamic epidemiological inferences are, especially when there is uncertainty regarding pathogen prevalence and sampling intensity. Here, we use recently developed mathematical techniques to fully characterize the information that can possibly be extracted from serially collected viral phylogenetic data, in the context of the commonly used birth-death-sampling model. We show that for any candidate epidemiological scenario, there exists a myriad of alternative, markedly different, and yet plausible "congruent" scenarios that cannot be distinguished using phylogenetic data alone, no matter how large the data set. In the absence of strong constraints or rate priors across the entire study period, neither maximum-likelihood fitting nor Bayesian inference can reliably reconstruct the true epidemiological dynamics from phylogenetic data alone; rather, estimators can only converge to the "congruence class" of the true dynamics. We propose concrete and feasible strategies for making more robust epidemiological inferences from viral phylogenetic data.

Unifying Phylogenetic Birth-Death Models in Epidemiology and Macroevolution

Birth–death stochastic processes are the foundations of many phylogenetic models and are widely used to make inferences about epidemiological and macroevolutionary dynamics. There are a large number of birth–death model variants that have been developed; these impose different assumptions about the temporal dynamics of the parameters and about the sampling process. As each of these variants was individually derived, it has been difficult to understand the relationships between them as well as their precise biological and mathematical assumptions. Without a common mathematical foundation, deriving new models is nontrivial. Here, we unify these models into a single framework, prove that many previously developed epidemiological and macroevolutionary models are all special cases of a more general model, and illustrate the connections between these variants. This unification includes both models where the process is the same for all lineages and those in which it varies across types. We also outline a straightforward procedure for deriving likelihood functions for arbitrarily complex birth–death(-sampling) models that will hopefully allow researchers to explore a wider array of scenarios than was previously possible. By rederiving existing single-type birth–death sampling models, we clarify and synthesize the range of explicit and implicit assumptions made by these models. [Birth–death processes; epidemiology; macroevolution; phylogenetics; statistical inference.]

Variable routes to genomic and host adaptation among coronaviruses

Natural selection operating on the genomes of viral pathogens in different host species strongly contributes to adaptation facilitating host colonization. Here, we analyse, quantify and compare viral adaptation in genomic sequence data derived from seven zoonotic events in the Coronaviridae family among primary, intermediate and human hosts. Rates of nonsynonymous (d_N) and synonymous (d_S) changes on specific amino acid positions were quantified for each open reading frame (ORF). Purifying selection accounted for 77% of all sites under selection. Diversifying selection was most frequently observed in viruses infecting the primary hosts of each virus and predominantly occurred in the orf1ab genomic region. Within all four intermediate hosts, diversifying selection on the spike gene was observed either solitarily or in combination with orf1ab and other genes. Consistent with previous evidence, pervasive diversifying selection on coronavirus spike genes corroborates the role this protein plays in host cellular entry, adaptation to new hosts and evasion of host cellular immune responses. Structural modelling of spike proteins identified a significantly higher proportion of sites for SARS‐CoV‐2 under positive selection in close proximity to sites of glycosylation relative to the other coronaviruses. Among human coronaviruses, there was a significant inverse correlation between the number of sites under positive selection and the estimated years since the virus was introduced into the human population. Abundant diversifying selection observed in SARS‐CoV‐2 suggests the virus remains in the adaptive phase of the host switch, typical of recent host switches. A mechanistic understanding of where, when and how genomic adaptation occurs in coronaviruses following a host shift is crucial for vaccine design, public health responses and predicting future pandemics.

Adverse childhood experiences, epigenetics and telomere length variation in childhood and beyond: a systematic review of the literature

A systematic review following PRISMA guidelines was conducted to answer the question: What epigenetic, telomeric and associated biological changes are associated with exposure to adverse childhood experiences (ACEs) in the under 12s? Using PRISMA guidelines, appropriate databases were searched. 190 papers were returned with 38 articles fully reviewed. Articles were each independently quality rated by two authors using the Crowe Critical Appraisal Tool and data were extracted. Of the 38 articles, 23 were rated as very high quality. Most study participants were adults (n = 7769) with n = 727 child participants. Only seven of the very/high-quality studies were prospective and involved children. Methylation was the most studied method of epigenetic modification. There is some evidence supporting epigenetic modification of certain markers in participants exposed to ACEs measured in adulthood. Research is lacking on non-coding aspects of the epigenome and on coding aspects other than DNA methylation. There is some evidence of a more powerful effect on telomere length if physical neglect was involved. Much further work is required to model biological and psychological effects of epigenetic changes during childhood using prospective study designs. The effect of ACEs on the cellular ageing process during childhood is inadequately investigated and relies solely on measure of telomere length. Future research suggestions are proposed.

Early administration of interleukin-6 inhibitors for patients with severe COVID-19 disease is associated with decreased intubation, reduced mortality, and increased discharge

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Observational data on interleukin-6 receptor inhibitors (IL6ri) for COVID-19 disease are reported.

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IL6ri therapy was found to be associated with improved COVID-19 outcomes.

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The treatment benefit was greatest when therapy was initiated early during the disease course.

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IL6ri therapy appears to be superior to remdesivir and dexamethasone.

Objective

The aim of this observational study was to determine the optimal timing of interleukin-6 receptor inhibitor (IL6ri) administration for coronavirus disease 2019 (COVID-19).

Methods

Patients with COVID-19 were given an IL6ri (sarilumab or tocilizumab) based on iteratively reviewed guidelines. IL6ri were initially reserved for critically ill patients, but after review, treatment was liberalized to patients with lower oxygen requirements. Patients were divided into two groups: those requiring ≤45% fraction of inspired oxygen (FiO₂) (termed stage IIB) and those requiring >45% FiO₂ (termed stage III) at the time of IL6ri administration. The main outcomes were all-cause mortality, discharge alive from hospital, and extubation.

Results

A total of 255 COVID-19 patients were treated with IL6ri (149 stage IIB and 106 stage III). Patients treated in stage IIB had lower mortality than those treated in stage III (adjusted hazard ratio (aHR) 0.24, 95% confidence interval (CI) 0.08–0.74). Overall, 218 (85.5%) patients were discharged alive. Patients treated in stage IIB were more likely to be discharged (aHR 1.43, 95% CI 1.06–1.93) and were less likely to be intubated (aHR 0.43, 95% CI 0.24–0.79).

Conclusions

IL6ri administration prior to >45% FiO₂ requirement was associated with improved COVID-19 outcomes. This can guide clinical management pending results from randomized controlled trials.

Detection of HIV transmission hotspots in British Columbia, Canada: A novel framework for the prioritization and allocation of treatment and prevention resources

Background

Identifying populations at high risk of HIV transmission is critical for prioritizing treatment and prevention resources and achieving the UNAIDS 90-90-90 Targets.

Methods

HIV transmission rates can be estimated from phylogenetic trees as viral lineage-level diversification rates. To identify HIV-1 transmission foci in British Columbia, Canada, we inferred diversification rates from phylogenetic trees of 36 271 HIV-1 sequences from 9630 anonymized individuals. Diversification rates were combined with sociodemographic and clinical data, then aggregated by patients’ area of residence to predict the distribution of new HIV cases between 2008 and 2018. The predictive power of the model was compared with a phylogenetically uninformed model.

Findings

Aggregated diversification rate measures were predictive of new HIV cases in the subsequent year after adjusting for prevalent and incident cases in the previous year. For every one-unit increase in the mean of the top five diversification rates, the number of new HIV cases increased by on average 1·38-fold (95% CI, 1·28–1·49). In a blind prediction of 2018 cases, diversification rate improved the model's specificity by 12%, accuracy by 9%, top 20 agreement by 100%, and correlation of predicted and observed values by 162% relative to a model that incorporated epidemiological data alone.

Interpretation

By predicting the distribution of future HIV cases, a combined phylogenetic and epidemiological approach identifies hotspots where public health resources are needed most.

Funding

Canadian Institutes of Health Research, University of British Columbia, Public Health Agency of Canada, Genome Canada, Genome BC, Michael Smith Foundation for Health Research, and BC Centre for Excellence in HIV/AIDS.

RePHILL: protocol for a randomised controlled trial of pre-hospital blood product resuscitation for trauma

OBJECTIVES

To describe the 'Resuscitation with Pre-HospItaL bLood products' trial (RePHILL) - a multi-centre randomised controlled trial of pre-hospital blood product (PHBP) administration vs standard care for traumatic haemorrhage.

BACKGROUND

PHBP are increasingly used for pre-hospital trauma resuscitation despite a lack of robust evidence demonstrating superiority over crystalloids. Provision of PHBP carries additional logistical and regulatory implications, and requires a sustainable supply of universal blood components.

METHODS

RePHILL is a multi-centre, two-arm, parallel group, open-label, phase III randomised controlled trial currently underway in the UK. Patients attended by a pre-hospital emergency medical team, with traumatic injury and hypotension (systolic blood pressure <90 mmHg or absent radial pulse) believed to be due to traumatic haemorrhage are eligible. Exclusion criteria include age <16 years, blood product receipt on scene prior to randomisation, Advanced Medical Directive forbidding blood product administration, pregnancy, isolated head injury and prisoners. A total of 490 patients will be recruited in a 1 : 1 ratio to receive either the intervention (up to two units of red blood cells and two units of lyophilised plasma) or the control (up to four boluses of 250 mL 0.9% saline). The primary outcome measure is a composite of failure to achieve lactate clearance of ≥20%/h over the first 2 hours after randomisation and all-cause mortality between recruitment and discharge from the primary receiving facility to non-acute care. Secondary outcomes include pre-hospital time, coagulation indices, in-hospital transfusion requirements and morbidity.

RESULTS

Pilot study recruitment began in December 2016. Approval to proceed to the main trial was received in June 2017. Recruitment is expected to continue until 2020.

CONCLUSIONS

RePHILL will provide high-quality evidence regarding the efficacy and safety of PHBP resuscitation for trauma.

Methylmalonic Aciduria Secondary to Selective Cobalamin Malabsorption in a Yorkshire Terrier

An 8 wk old male Yorkshire terrier was presented with a 2 wk history of recurrent hypoglycemia, lethargy, and seizures. Investigations revealed a marked increase in blood ammonia, low serum cobalamin, and increased levels of urinary methylmalonic acid (MMA) excretion. No liver vascular abnormality was detected. The patient was diagnosed with methylmalonic aciduria due to cobalamin malabsorption. The patient responded well to parenteral cobalamin administration, and the urinary MMA levels normalized rapidly following instigation of treatment. Due to the suspected hereditary nature of selective cobalamin deficiency, one sibling of this dog was screened and found to be normal. This is the first reported case of MMA secondary to hypocobalaminemia in Yorkshire terriers, and the second report of this disease in a dog in the United Kingdom. Given the fact that clinical signs of MMA are similar to those seen in dogs with portosystemic shunts and that Yorkshire terriers are predisposed to liver vascular abnormalities, this case report adds important clinical information to the current available literature.

Traumatic spinal cord injury caused by suspected hyperflexion of the atlantoaxial joint in a 10-year-old cat

Case summary

A 10-year-old cat presented 5 days after a traumatic event with acute recumbency followed by some clinical improvement. The neuroanatomical localisation was the C1–C5 spinal cord segments. Initial survey radiographs, including lateral flexed views, showed no convincing abnormalities. Magnetic resonance imaging (MRI) revealed a marked focal intramedullary lesion at the level of the dens and suspected oedema extending over C2–C3 vertebrae, suggesting early syrinx formation. The cat made an initial excellent recovery on restricted exercise without medical treatment. The MRI changes largely resolved on follow-up MRI 4 weeks later yet recurred following a relapse 4 months later. At this stage, a post-traumatic syrinx had developed. Moreover, the suspected atlantoaxial instability was finally diagnosed on radiography with fully flexed lateral views. A hyperflexion injury causing tearing of the atlantoaxial ligaments was considered most likely given the lack of malformations or fractures. The cat made a full recovery on conservative management.

Relevance and novel information

This is the first report of sequential MRI findings in a cat with atlantoaxial instability. Moreover, post-traumatic syringomyelia formation following atlantoaxial injury has not been reported. Sequential MRI aids in the diagnosis of hyperflexion injury if survey radiographs fail to identify atlantoaxial instability.

Obstetric skills drills: evaluation of teaching methods

OBJECTIVE

To determine the most effective method of delivering training to staff on the management of an obstetric emergency.

SUBJECTS

The research was conducted in a District General Hospital in the UK, delivering approximately 3500 women per year. Thirty-six staff, comprising of junior and senior medical and midwifery staff were included as research subjects. Each of the staff members were put into one of six multi-professional teams. Effectively, this gave six teams, each comprising of six members.

METHOD

Three teaching methods were employed. Lecture based teaching (LBT), simulation based teaching (SBT) or a combination of these two (LAS). Each team of staff were randomly allocated to undertake a full day of training in the management of Post Partum Haemorrhage utilising one of these three teaching methods. Team knowledge and performance were assessed pre-training, post training and at three months later. In addition to this assessment of knowledge and performance, qualitative semi-structured interviews were carried out with 50% of the original cohort one year after the training, to explore anxiety, confidence, communication, knowledge retention, enjoyment and transferable skills.

RESULTS

All teams improved in their performance and knowledge. The teams taught using simulation only (SBT) were the only group to demonstrate sustained improvement in clinical management of the case, confidence, communication skills and knowledge. However, the study did not have enough power to reach statistical significance. The SBT group reported transferable skills and less anxiety in subsequent emergencies. SBT and LAS reported improved multidisciplinary communication. Although tiring, the SBT was enjoyed the most.

CONCLUSION

Obstetrics is a high risk speciality, in which emergencies are to some extent, inevitable. Training staff to manage these emergencies is a fundamental principal of risk management. Traditional risk management strategies based on incident reporting and event analysis are reactive and not always effective. Simulation based training is an appropriate proactive approach to reducing errors and risk in obstetrics, improving teamwork and communication, whilst giving the student a multiplicity of transferable skills to improve their performance.

The immunomodulatory actions of E-type prostaglandins

Prostaglandins (PGs) have been recognised as modulators of immune responses. This has been proved by both in vitro studies and from observations in animals and humans. Administration of prostaglandins for therapeutic purposes, however, has been hampered by their limited bioavailability and their pleiotropic effects, with resultant toxicological profile. Despite this, some success has been demonstrated in the clinic for the control of graft rejection, especially when used as part of a broader immunosuppressant regimen. Full realisation of the therapeutic potential of prostaglandins will depend on a better understanding of their mechanism of action at the cellular level. Recently, it has been appreciated that prostaglandins do not merely inhibit T-cell function, but appear to modulate the profile of lymphocyte sub-populations through regulation of cytokine synthesis and release. Recent efforts have also begun to focus on identifying prostaglandin receptor subtypes important for immune regulation and offer a means, together with targeted delivery, of utilising the immunosuppressant/anti-inflammatory effects of E-type prostaglandins in a safe and effective manner.

New method to evaluate the practice of positive pressure ventilation in intensive care units

BACKGROUND

There is good evidence to support the use of a "protective" ventilation strategy, using small tidal volumes and inspiratory pressures, in patients with acute respiratory distress syndrome. Many general intensive care units in the UK are being slow to adopt this approach and we therefore set out to devise a method to audit ventilation and possibly influence practice in these units.

METHODS

Using variables that are routinely documented by intensive care nurses, we assessed the relationship between ventilator settings and arterial blood gas values on 30 consecutive ventilated patients admitted to intensive care units at both a teaching and a district hospital. Data were recorded twice daily and the proportions of data points where there was unnecessary hyperventilation were recorded at each centre.

RESULTS

The initial audit results showed clear differences in practice between the teaching hospital and the district hospital. After an intensive education programme, during which an active role for nursing staff in ventilator management was encouraged, supported by simple protocols, practice in the district hospital was re-audited and found to closely mirror that in the teaching centre.

CONCLUSIONS

To assist progress towards the use of a "protective" ventilation strategy in intensive care units in the UK, we devised a simple, robust audit method. We have shown how this method can give a more uniform practice of ventilation in critical care units, with the introduction of nurse-run protocols.

Direct optometrist referral of cataract patients into a pilot 'one-stop' cataract surgery facility

OBJECTIVES

To determine the feasibility of a) direct optometrist referral of patients with cataract, and b) combined assessment with same day cataract surgery ('one stop' cataract surgery).

METHODS

Evaluation of 169 patients referred directly by optometrists into a pilot 'one stop' cataract surgery facility.

RESULTS

Of 169 referrals, 160 patients (94.7%) were given confirmed appointments for the 'one stop' cataract service and 9 patients (5.3%) were appointed conventionally. Of 160 patients attending the 'one stop' cataract service, 154 patients (96.3%) underwent cataract surgery at the same visit, in 4 patients (2.5%) cataract surgery was indicated but deferred and in 2 patients (1.3%) cataract surgery was not indicated. The referral was supplemented with information regarding the patient's medical history forwarded by the general practitioner for 3 patients (1.8%). There were no systemic or sight-threatening complications. 151 patients (98.1%) achieved a visual acuity of 6/12 or better at a mean of 31 days post-operatively.

CONCLUSION

Optometrists can accurately predict the need for cataract surgery and refer directly into a pilot 'one stop' cataract surgery facility, without the need for general practitioner involvement. 'One stop' cataract surgery is feasible; benefits to the patient include the abolition of the need to visit the general practitioner for consultation and referral, and the hospital for pre-assessment.

Scintigraphic patterns of injury in amateur weight lifters

PURPOSE

Weight lifting is now a standard part of training in most sports. An increasing number of amateur athletes are doing strength training, mostly in unsupervised situations. A series of injuries in amateur weight lifters was analyzed by bone scintigraphy, with the aim of depicting specific patterns that would accurately identify the primary lesions.

METHODS

Twelve patients (10 men and 2 women) were studied whose ages ranged from 18 to 35 years. Patients were referred for bone scintigraphy with clinical diagnoses based on history, physical examination, and appropriate radiologic investigations. Diagnoses were confirmed by surgery, arthroscopy, arthrography, local steroid injection, and outcome.

RESULTS

Most of the injuries were in athletes undertaking free-weight training. Most injuries were in the upper limbs, particularly around the shoulder. Scintigraphic patterns of supraspinatus and bicipital tendons and also rotator cuff lesions were identified. Clavicular osteolysis, avulsion injuries, muscle damage, and vertebral lesions were also noted. Several abnormalities revealed by scintigraphy were clinically unsuspected.

CONCLUSIONS

Scintigraphic manifestations of several injuries, particularly around the shoulder, have a specific pattern. Recognition of these patterns can enhance the performance of bone scintigraphy. Scintigraphy also has the potential to detect clinically unsuspected disease.

Catheter patrols: a unique way to reduce the use of convenience urinary catheters

The increased risk of infections among elders has been was documented. Elder patients often have atypical signs and symptoms that lead to delays in diagnosis and treatment of infection. Urinary incontinence is often overlooked as a sign of infection because of the stereotypical belief that urinary incontinence is a normal part of the aging process. This belief can lead to overuse of indwelling urinary catheters and place the elder patient at even greater risk for infection. The Centers for Disease Control and Prevention's "Guidelines for Prevention of Catheter-Associated Urinary Tract Infections" lists four criteria that are helpful in determining appropriate urinary catheter usage. These guidelines, along with ongoing nursing assessment of the patient's urinary catheter need, play an important role in protecting elder patients from unnecessary catheter-associated urinary tract infections.

Noise levels in a cardiac surgical intensive care unit: a preliminary study conducted in secret

Noise in hospitals frequently exceeds recommended levels and has detrimental psychological and physiological effects on patients and staff. The aim of this study was to record the noise levels within the cardiac surgical intensive care unit (CSICU) environment in secret. The device used was a CEL Instruments environmental noise meter concealed in a dummy box featuring temperature and humidity digital displays. It allowed greater than 16 hours recording time at a 1-minute resolution. The 24-hour period was covered by overlapping recordings. The data collected were downloaded onto a personal computer for analysis. The maximum sound level recorded was 100.9 decibel level (dBA), 1 min Lmax (the maximum sound level occurring in a 1-min period). The minimum sound level was 61.3 dBA 1 min Lmax. The continuous background noise was at its lowest at 57.5 dBA 1 min equivalent continuous sound pressure levels (Leq) and at its peak 77.3 dBA 1 min Leq. Noise in the CSICU was above the recommended levels for patients and staff well-being. Future studies will be designed to establish a correlation between sound levels and events.

Cerebral magnetic resonance image segmentation using data fusion

OBJECTIVE

A semiautomated method is described for segmenting dual echo MR head scans into gray and white matter and CSF. The method is applied to brain scans of 80 healthy children and adolescents.

MATERIALS AND METHODS

A probabilistic data fusion equation was used to combine simultaneously acquired T2-weighted and proton density head scans for tissue segmentation. The fusion equation optimizes the probability of a voxel being a particular tissue type, given the corresponding probabilities from both images. The algorithm accounts for the intensity inhomogeneities present in the images by fusion of local regions of the images.

RESULTS

The method was validated using a phantom (agarose gel with iron oxide particles) and hand-segmented images. Gray and white matter volumes for subjects aged 20-30 years were close to those previously published. White matter and CSF volume increased and gray matter volume decreased significantly across ages 4-18 years. White matter, gray matter, and CSF volumes were larger for males than for females. Males and females showed similar change of gray and white matter volumes with age.

CONCLUSION

This simple, reliable, and valid method can be employed in clinical research for quantification of gray and white matter and CSF volumes in MR head scans. Increase in white matter volume may reflect ongoing axonal growth and myelination, and gray matter reductions may reflect synaptic pruning or cell death in the age span of 4-18 years.

A technique for single-channel MR brain tissue segmentation: application to a pediatric sample

A segmentation method is presented for gray matter, white matter, and cerebrospinal fluid (CSF) in thin-sliced single-channel brain magnetic resonance (MR) scans. The method is based on probabilistic modeling of intensity distributions and on a region growing technique. Interrater and intrarater reliabilities for the method were high, and comparison with phantom studies and hand-traced results from an experienced rater indicated good validity. The method was designed to account for spatially dependent image intensity inhomogeneities. Segmentation of MR brain scans of 105 (56 male and 49 female) healthy children and adolescents showed that although the total brain volume was stable over age 4-18, white matter increased and gray matter decreased significantly. There were no sex differences in total gray and white matter growth after correction for total brain volume. White matter volume increased the most in superior and posterior regions and laterality effects were seen in hemisphere tissue volumes. These findings are consistent with other reports, and further validate the segmentation technique.

An EP receptor with a novel pharmacological profile in the T-cell line Jurkat

1. Comparison of the rank order of potency of the natural prostanoids prostaglandin E2 (PGE2), PGD2, PGF2 alpha and carbaprostacyclin in stimulating cyclic AMP in Jurkat cells is consistent with the presence of an EP receptor. 2. Lack of responsiveness to the EP1/EP3 selective agonist, sulprostone, and the EP2 agonists, butaprost and AH 13205, indicates that this receptor is not of the EP1, EP2 or EP3 subtypes. 3. Inhibition of PGE2-stimulated cyclic AMP by the EP4 antagonist, AH 23848 is non-competitive, unlike the competitive antagonism reported in the pig saphenous vein EP4 preparation. Furthermore, 16,16-dimethyl PGE2 is 100 fold less potent than PGE2 in Jurkat cells, while these agonists are equipotent in the rabbit jugular vein purported EP4 preparation. In addition, 1-OH PGE1, which also is active in the rabbit jugular vein preparation, is inactive in Jurkat cells at concentrations up to 1 x 10(-4) M. These data are not wholly consistent with any adenylate cyclase coupled EP receptor described to date. 4. It is postulated that an EP receptor, positively coupled to adenylate cyclase, with a unique pharmacological profile is present in Jurkat cells.

The antiinflammatory activity of topically applied novel calcium-channel antagonists

The antiinflammatory activities of two novel calcium-channel antagonists, AGN 190742 and AGN 190744, were evaluated in murine models of cutaneous inflammation. These 2(5H)-furanone ring compounds block both depolarization-dependent Ca2+ entry and receptor-mediated responses in GH3 cells. Topical application of AGN 190742 or AGN 190744 inhibits neutrophil infiltration and epidermal hyperplasia induced by repeated treatment of mouse skin with phorbol ester. AGN 190744 also is active in an arachidonic acid model of acute inflammation. These data suggest that topical application of calcium-channel antagonists can inhibit cutaneous inflammatory responses and that AGN 190742 and/or AGN 190744 may serve as useful pharmacological probes for examining these responses in vivo.

Adsorption of cations to phosphatidylinositol 4,5-bisphosphate

We investigated the binding of physiologically and pharmacologically relevant ions to the phosphoinositides by making 31P NMR, electrophoretic mobility, surface potential, and calcium activity measurements. We studied the binding of protons to phosphatidylinositol 4,5-bisphosphate (PIP2) by measuring the effect of pH on the chemical shifts of the 31P NMR signals from the two monoester phosphate groups of PIP2. We studied the binding of potassium, calcium, magnesium, spermine, and gentamicin ions to the phosphoinositides by measuring the effect of these cations on the electrophoretic mobility of multilamellar vesicles formed from mixtures of phosphatidylcholine (PC) and either phosphatidylinositol, phosphatidylinositol 4-phosphate, or PIP2; the adsorption of these cations depends on the surface potential of the membrane and can be described qualitatively by combining the Gouy-Chapman theory with Langmuir adsorption isotherms. Monovalent anionic phospholipids, such as phosphatidylserine and phosphatidylinositol, produce a negative electrostatic potential at the cytoplasmic surface of plasma membranes of erythrocytes, platelets, and other cells. When the electrostatic potential at the surface of a PC/PIP2 bilayer membrane is -30 mV and the aqueous phase contains 0.1 M KCl at pH 7.0, PIP2 binds about one hydrogen and one potassium ion and has a net charge of about -3. Our mobility, surface potential, and electrode measurements suggest that a negligible fraction of the PIP2 molecules in a cell bind calcium ions, but a significant fraction may bind magnesium and spermine ions.

An in vivo phosphorus nuclear magnetic resonance study of the variations with age in the phosphodiester content of human muscle

Human gastrocnemius and slow twitch muscles contain phosphodiesters that may be detected in vivo by phosphorus nuclear magnetic resonance (NMR). This work represents a study of 354 spectra obtained from healthy subjects of various ages and from patients with peripheral vascular disease. The analysis of the data indicate a correlation between the concentration of phosphodiesters and age. By comparing the data obtained with healthy subjects and patients it is concluded that the increase in phosphodiesters is not due to disease, but to ageing itself. The significance of this increase is discussed.