Prevalence and Antimicrobial Resistance of Salmonella Dublin and Thermotolerant Campylobacter in Liver from Veal Calves in Québec, Canada

Salmonella Dublin and Campylobacter spp. are two foodborne pathogens of importance. A small number of studies reported that consumption of veal liver was associated with an increased risk of human illness from these two pathogens. To better characterize the risk of exposure from liver, a cross-sectional study was conducted to estimate the prevalence of white veal calf liver contamination with these two pathogens and to characterize the antimicrobial non-susceptibility patterns of isolates. Veal liver samples were collected at two slaughterhouses in Quebec, Canada, in 2016 and 2017. Samples were submitted for polymerase chain reaction (PCR) screening followed by culture of Salmonella and thermotolerant Campylobacter. Isolates were tested for antimicrobial susceptibility using broth microdilution. Salmonella Dublin was the only serotype cultured from 3.6% (95% confidence interval [CI]: 0.0-7.9) of 560 liver samples. Among them and for technical reasons, 498 were tested by PCR for Campylobacter. The prevalence of PCR-positive livers was estimated to be 65.8% (95% CI: 58.7-72.9) for Campylobacter jejuni and 7.0% (95% CI: 3.9-10.1%) for Campylobacter coli. Fourteen Salmonella Dublin isolates were submitted for antimicrobial resistance (AMR) testing; all were non-susceptible to at least eight antimicrobials from six different classes. Most (81.4%) of the 188 C. jejuni isolates submitted for AMR testing were non-susceptible to tetracycline, and 23.0% of isolates were non-susceptible to nalidixic acid and ciprofloxacin. Of the seven C. coli isolates, four were multidrug resistant. This study highlights the importance of veal liver as a potential source of exposure to multidrug-resistant Salmonella Dublin and thermotolerant Campylobacter spp.

Bayesian accuracy estimates of environmental sampling for determining herd paratuberculosis infection status and its association with the within-herd individual fecal culture prevalence in Québec dairies

The objectives of this retrospective analysis were to: 1) estimate the diagnostic sensitivity (Se) and specificity (Sp) of bacterial culture of environmental samples for determining Mycobacterium avium subsp. paratuberculosis (MAP) infection status in Québec dairies, using a Bayesian Latent Class Model (BLCM); and 2) determine the association between the number of positive environmental samples and the individual fecal culture (IFC) apparent and true MAP within-herd prevalence. Environmental and individual fecal samples were collected from 87 commercial dairy herds participating in previous research projects. Environmental samples included two composite samples of 20 g collected from different locations within each of the following sites: an area where manure from the majority of adult cattle accumulates, a manure storage area and another site of manure accumulation chosen by the veterinarian. Samples were cultured using the MGIT Para TB culture liquid media and the BACTEC MGIT 960 system. The Se and Sp of environmental sampling were estimated using a one-test-one-population BLCM. Herds were considered positive for environmental sampling if at least one out of the six samples collected was positive. The apparent and true IFC within-herd MAP prevalence estimates for each herd were obtained using a two-stage cluster BLCM, then merged in a single dataset with the environmental sample results. The association between the within-herd MAP prevalence results (apparent and true), and the number of positive environmental samples was assessed using a zero-inflated negative binomial (ZINB) model. In all BLCMs, median posterior estimates and 95 % Bayesian credible intervals (BCI) were obtained with OpenBUGS statistical freeware. Se and Sp of environmental sampling were 43.7 % (95 % BCI: 32.5-55.5) and 96.2 % (95 % BCI: 84.2-99.8), respectively. Overall, the number of positive environmental samples increased with the apparent and true MAP within-herd prevalence. The true prevalence was higher than the apparent prevalence for a given number of positive environmental samples. The probability of not observing a positive environmental sample decreased with the prevalence. Despite its imperfect accuracy, environmental sampling is an inexpensive and non-invasive sampling method to determine MAP infection status in tie-stall herds that can be used as a proxy to estimate the true within-herd prevalence. The absence of positive environmental samples in a single sampling visit is likely an indicator of a very low within-herd prevalence rather than being MAP exempt.

Evaluation of the feasibility and impacts of in situ simulation in emergency medicine-a mixed-method study protocol

INTRODUCTION

In situ simulation (ISS) consists of performing a simulation in the everyday working environment with the usual team members. The feasibility of ISS in emergency medicine is an important research question, because ISS offers the possibility for repetitive, regular simulation training consistent with specific local needs. However, ISS also raises the issue of safety, since it might negatively impact the care of other patients in the emergency department (ED). Our hypothesis is that ISS in an academic high-volume ED is feasible, safe and associated with benefits for both staff and patients.

METHODS

A mixed-method, including a qualitative method for the assessment of feasibility and acceptability and a quantitative method for the assessment of patients' safety and participants' psychosocial risks, will be used in this study.Two distinct phases are planned in the ED of the CHU de Québec-Université Laval (Hôpital de l'Enfant-Jésus) between March 2021 and October 2021. Phase 1: an ISS programme will be implemented with selected ED professionals to assess its acceptability and safety and prove the validity of our educational concept. The number of cancelled sessions and the reasons for cancellation will be collected to establish feasibility criteria. Semistructured interviews will evaluate the acceptability of the intervention. We will compare unannounced and announced ISS. Phase 2: the impact of the ISS programme will be measured with validated questionnaires for the assessment of psychosocial risks, self-confidence and perceived stress among nonselected ED professionals, with comparison between those exposed to ISS and those that were not.

ETHICS AND DISSEMINATION

The CHU de Québec-Université Laval Research ethics board has approved this protocol (#2020-5000). Results will be presented to key professionals from our institution to improve patient safety. We also aim to publish our results in peer-reviewed journals and will submit abstracts to international conferences to disseminate our findings.

Neonatal Microsurgical Repair of a Congenital Abdominal Aortic Aneurysm with a Cadaveric Graft

Congenital abdominal aortic aneurysms (AAA) are an extremely rare entity. We present the case of a female fetus diagnosed with an AAA on routine prenatal ultrasound. A postnatal computed tomography angiogram revealed an infrarenal AAA with a narrow proximal neck. Surgery was performed on day of life 14 using a cadaveric femoral artery graft. The proximal anastomosis was performed under the microscope given the severity of the aortic stenosis and the proximity of the renal arteries. The patient's postoperative course was uneventful and she is developing normally 1 year after surgery. The graft remains permeable, albeit with evidence of proximal and distal stenosis and graft calcification on imaging.

Postoperative outcomes in surgical COVID-19 patients: a multicenter cohort study

BACKGROUND

Data on postoperative outcomes of the COVID-19 patient population is limited. We described COVID-19 patients who underwent a surgery and the pandemic impact on surgical activities.

METHODS

We conducted a multicenter cohort study between March 13 and June 192,020. We included all COVID-19 patients who underwent surgery in nine centres of the Province of Québec, the Canadian province most afflicted by the pandemic. We also included concomitant suspected COVID-19 (subsequently confirmed not to have COVID-19) patients and patients who had recovered from it. We collected data on baseline characteristics, postoperative complications and postoperative mortality. Our primary outcome was 30-day mortality. We also collected data on overall surgical activities during this first wave and during the same period in 2019.

RESULTS

We included 44 COVID-19 patients, 18 suspected patients, and 18 patients who had recovered from COVID-19 at time of surgery. Among the 44 COVID-19 patients, 31 surgeries (71%) were urgent and 16 (36%) were major. In these patients, pulmonary complications were frequent (25%) and 30-day mortality was high (15.9%). This mortality was higher in patients with symptoms (23.1%) compared to those without symptoms (5.6%), although not statistically significant (p = 0.118). Of the total 22,616 cases performed among participating centres during the study period, only 0.19% had COVID-19 at the time of surgery. Fewer procedures were performed during the study period compared to the same period in 2019 (44,486 cases).

CONCLUSION

In this Canadian cohort study, postoperative 30-day mortality in COVID-19 patients undergoing surgery was high (15.9%). Although few surgeries were performed on COVID-19 patients, the pandemic impact on surgical activity volume was important.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04458337 .

Chart Audit of Spiritual Care Documentation: Continuous Quality Improvement

Eight spiritual care practitioners at an acute care teaching hospital undertook a systematic chart audit of their documentation practices in the patient electronic health record. The purpose was to evaluate their practices using the standards of their professional association and regulatory college. A preliminary "mock audit" was essential for the overall success of the audit. Plans for ongoing chart audits will lead to continuous quality improvement. A limitation was that their manager acted as both improvement coach and performance evaluator.

Evolving systems of care: Individuals found not criminally responsible on account of mental disorder in custody of civil and forensic psychiatric services

Following psychiatric deinstitutionalization and changes in involuntary civil commitment laws, many individuals with severe mental disorders have been receiving mental health services through the back door, that is, the criminal justice system. Significant changes to the section of Criminal Code of Canada dealing with individuals with mental disorders have led to significant annual increases in the number of individuals declared Not criminally responsible on account of mental disorder (NCRMD), many of whom are directed to civil psychiatric settings. The goal of the present study was to describe the psychosociocriminological and risk characteristics of individuals found NCRMD remanded to civil psychiatric hospitals (CPH) compared to a forensic psychiatric hospital (FPH). This study was conducted between October 2004 and August 2006 in the sole FPH of the province of Québec and two large CPH in the Montréal metropolitan area. The final sample for the current study consisted of 96 men: 60 from the FPH and 36 from the two CPH. Results indicate that individuals in both settings have similar psychosociocriminal profiles, including PCL-R scores, but that individuals in CPH have higher scores in the Risk subscale of the HCR-20 than do their counterparts in the FPH. This difference is due to a higher score on two items: exposure to destabilizing factors and noncompliance with remediation attempts. Results are discussed in terms of the need for civil psychiatric settings to implement risk assessment and management programs into their services, and the need for further research into forensic mental health services.

Oral Lorazepam is not Superior to Placebo for Lowering Stress in Children Before Digestive Endoscopy: A Double-Blind, Randomized, Controlled Trial

BACKGROUND

Digestive endoscopies must be performed within a safe and comfortable environment. We have previously shown that the quality of intravenous sedation is influenced by preoperative stress.

AIM

Our primary objective was to compare the effects of oral lorazepam and placebo on the salivary cortisol response of children undergoing a digestive endoscopy. Secondary objectives were the assessment of procedural pain and comfort as well as the occurrence of adverse events.

METHODS

Participants were randomized and received either lorazepam, placebo, or no premedication. Saliva was collected upon arrival at the hospital and 1 h following randomization. The sedation protocol included midazolam and fentanyl ± ketamine. Procedural pain was evaluated with the Nurse Assessed Patient Comfort Score (NAPCOMS). Patients completed a postoperative questionnaire. The primary outcome was defined as the proportion of children having a cortisol decrease ≥ 15 nmol/L.

RESULTS

101 participants (54 females) were included. The rate of children having a cortisol decrease ≥ 15 nmol/L was 27.3%, 35.3%, and 19.4% for lorazepam, placebo, and no premedication, respectively (p = 0.356). The median (IQR) NAPCOMS pain score was 3.0 (0-6) for lorazepam, 4.4 (0-6) for placebo, and 3.4 (3-4) for no premedication (p = 0.428). With lorazepam, 75.9% of children reported experiencing a comfortable procedure, compared with 41.9% taking placebo and 34.5% with no premedication (p = 0.013). Transient tachycardia was the most frequent intraoperative adverse event, particularly with lorazepam (62.5%, p = 0.029).

CONCLUSIONS

Oral lorazepam had no effect on patients' preoperative stress, as measured by salivary cortisol, but was associated with a higher rate of comfortable procedures.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov, Identifier NCT03180632.

Genomic Investigation of the Emergence of Invasive Multidrug-Resistant Salmonella enterica Serovar Dublin in Humans and Animals in Canada

Salmonella enterica subsp. enterica serovar Dublin is a zoonotic pathogen that often leads to invasive bloodstream infections in humans that are multidrug resistant. Described here are the results of Canadian national surveillance of S Dublin from 2003 to 2015 in humans and bovines, principally collected through the Canadian Integrated Program for Antibiotic Resistance Surveillance (CIPARS). An increase in human infections due to multidrug-resistant (MDR) S Dublin was observed in 2010, many of which were bloodstream infections. Phylogenomic analysis of human and bovine isolates revealed a closely related network that differed by only 0 to 17 single nucleotide variants (SNVs), suggesting some potential transmission between humans and bovines. Phylogenomic comparison of global publicly available sequences of S Dublin showed that Canadian isolates clustered closely with those from the United States. A high correlation between phenotypic and genotypic antimicrobial susceptibility was observed in Canadian isolates. IS26 replication was widespread among U.S. and Canadian isolates and caused the truncation and inactivation of the resistance genes strA and blaTEM-1B A hybrid virulence and MDR plasmid (pN13-01125) isolated from a Canadian S Dublin isolate was searched against NCBI SRA data of bacteria. The pN13-01125 coding sequences were found in 13 Salmonella serovars, but S Dublin appears to be a specific reservoir. In summary, we have observed the rise of invasive MDR S Dublin in humans in Canada and found that they are closely related to bovine isolates and to American isolates in their mobile and chromosomal contents.

Age Dependent Dysfunction of Mitochondrial and ROS Metabolism Induced by Mitonuclear Mismatch

Mitochondrial and nuclear genomes have to coevolve to ensure the proper functioning of the different mitochondrial complexes that are assembled from peptides encoded by both genomes. Mismatch between these genomes is believed to be strongly selected against due to the consequent impairments of mitochondrial functions and induction of oxidative stress. Here, we used a Drosophila model harboring an incompatibility between a mitochondrial tRNA^tyr and its nuclear-encoded mitochondrial tyrosine synthetase to assess the cellular mechanisms affected by this incompatibility and to test the relative contribution of mitonuclear interactions and aging on the expression of impaired phenotypes. Our results show that the mitochondrial tRNA mutation caused a decrease in mitochondrial oxygen consumption in the incompatible nuclear background but no effect with the compatible nuclear background. Mitochondrial DNA copy number increased in the incompatible genotype but that increase failed to rescue mitochondrial functions. The flies harboring mismatch between nuclear and mitochondrial genomes had almost three times the relative mtDNA copy number and fifty percent higher rate of hydrogen peroxide production compared to other genome combinations at 25 days of age. We also found that aging exacerbated the mitochondrial dysfunctions. Our results reveal the tight interactions linking mitonuclear mismatch to mitochondrial dysfunction, mitochondrial DNA regulation, ROS production and aging.

Risk factors associated with Mycobacterium avium subsp. paratuberculosis herd status in Québec dairy herds

Paratuberculosis is a chronic and contagious enteric disease of ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP). Control of paratuberculosis is justified given the associated economic losses and the potential role of MAP in Crohn's disease in humans. Management practices that limit exposure of susceptible animals to MAP are more effective at reducing disease prevalence than testing and culling infected cows. The objective of this retrospective case-control study was to study the association between management practices and MAP status in dairy herds in Québec, Canada. A total of 26 case herds (MAP had been isolated from at least 1 environmental sample in each herd) and 91 control herds (no clinical cases of paratuberculosis and negative on 2 consecutive yearly environmental samplings) were selected among herds enrolled in the Québec Voluntary Paratuberculosis Control Program. A risk assessment questionnaire, completed at enrolment, was available for the selected herds. Culture of MAP was achieved using liquid media and the BACTEC 960 detection system. Multivariable logistic regression was used to evaluate the association between selected risk factors and MAP herd status. Herd size (OR = 1.17; 95% CI: 1.02-1.33) and proportion of cows purchased per year in the last 5 years (OR = 5.44; 95% CI: 1.23-23.98) were significantly associated with a positive MAP herd status. The management risk factors identified in the present study are in accord with previous studies. Management practices aiming to prevent the introduction of new animals into the herd and to reduce the contact of newborn calves with adult animals or their feces are key elements to minimize MAP introduction and transmission into a herd. These elements should be prioritized in control programs.

Incidence of fecal excretion of Mycobacterium avium subsp. paratuberculosis in dairy cows before and after the enrolment in the Québec voluntary program

Paratuberculosis is a chronic and contagious enteric disease of ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP). This disease of worldwide distribution is responsible for significant economic losses and the bacteria itself has been linked to human Crohn's disease. Paratuberculosis control programs focus on reducing MAP transmission by implementing better management practices that target infection routes. In Québec, a Voluntary Paratuberculosis Prevention and Control Program (QVPPCP) was launched in 2007. The objectives of this prospective cohort study were threefold. The first was to describe the changes in the incidence of fecal excretion of MAP in cows born before and after farm enrolment in the QVPPCP. The second was to estimate the impact of the risk of within-herd transmission of MAP (measured by the risk assessment score (RAS)) on the incidence of fecal excretion of MAP. And the third was to evaluate the impact of calf rearing practices on the incidence of fecal excretion of MAP. Eighteen MAP-positive herds were visited annually from 2011 to 2015. At each visit, individual fecal samples from all adult cows were collected. MAP was cultured using liquid media and an automated system. A risk assessment questionnaire was completed upon enrolment in the QVPPCP and at each visit. The RAS of the farm was attributed to each cow according to its birthdate. Cox proportional hazards models were used to estimate the hazard ratios (HR) for the exposure variables. Herd clustering was taken into account using robust standard errors. A total of 2158 cows were included (cohort born before n=919; cohort born after n=1239). The incidence and hazard of fecal excretion were significantly lower for the cohort-after than the cohort-before (incidence rate ratio=0.38; 95% CI: 0.18-0.78 and HR=0.48; 95% CI: 0.23-0.98). The HR of fecal excretion for cows exposed to a high RAS was 2.20 times (95% CI: 1.21-3.99) that of cows exposed to a low RAS. Poor calving cow hygiene (HR=3.41; 95% CI: 1.40-8.31) and contact between pre-weaned heifers and adult cows or their feces were significantly associated with an increased hazard of fecal excretion of MAP (HR=2.66; 95% CI: 1.08-6.56). Our results suggest that enrolment in the QVPPCP reduces the risk of MAP fecal excretion. They support the hypothesis that contact between calves and adult cows or their feces increases MAP transmission. The incidence results also suggest that MAP prevalence could be reduced to low levels regardless of initial MAP prevalence.

Evaluation of a PCR assay on overgrown individual fecal samples cultured for Mycobacterium avium subsp. paratuberculosis

Microbial overgrowth can interfere with Mycobacterium avium subsp. paratuberculosis (MAP) growth and detection. We estimated the percentage of positive samples by PCR performed on the incubated media of individual fecal samples classified as non-interpretable (NI) by bacteriologic culture of liquid media. A total of 262 liquid cultures declared NI and 88 samples declared negative were included in the study. MAP DNA was detected in 7 NI samples (2.7%; 95% CI: 1.1–5.4%) and in 1 negative sample (1.1%; 95% CI: 0.3–6.2%). The PCR allowed the detection of MAP-positive samples that had been missed in the initial bacteriologic culture. However, the benefit of these few additional positive results must be weighed against the additional costs incurred. Using PCR to classify overgrown cultures optimizes the detection process and eliminates the NI outcome.

Determinants of virulence and of resistance to ceftiofur, gentamicin, and spectinomycin in clinical Escherichia coli from broiler chickens in Québec, Canada

Antimicrobials are frequently used for the prevention of avian colibacillosis, with gentamicin used for this purpose in Québec until 2003. Ceftiofur was also used similarly, but voluntarily withdrawn in 2005 due to increasing resistance. Spectinomycin-lincomycin was employed as a replacement, but ceftiofur use was partially reinstated in 2007 until its definitive ban by the poultry industry in 2014. Gentamicin resistance frequency increased during the past decade in clinical Escherichia coli isolates from broiler chickens in Québec, despite this antimicrobial no longer being used. Since this increase coincided with the use of spectinomycin-lincomycin, co-selection of gentamicin resistance through spectinomycin was suspected. Therefore, relationships between spectinomycin, gentamicin, and ceftiofur resistance determinants were investigated here. The distribution of 13 avian pathogenic E. coli virulence-associated genes and their association with spectinomycin resistance were also assessed. A sample of 586 E. coli isolates from chickens with colibacillosis in Québec between 2009 and 2013 was used. The major genes identified for resistance to ceftiofur, gentamicin, and spectinomycin were bla_CMY, aac(3)-VI, and aadA, respectively. The aadA and aac(3)-VI genes were strongly associated and shown to be located on a modified class 1 integron. The aadA and bla_CMY genes were negatively associated, but when present together, were generally located on the same plasmids. No statistical positive association was observed between aadA and virulence genes, and virulence genes were only rarely detected on plasmids encoding spectinomycin resistance. Thus, the use of spectinomycin-lincomycin may likely select for gentamicin but not ceftiofur resistance, nor for any of the virulence-associated genes investigated.

Detection of Mycobacterium avium subspecies paratuberculosis in tie-stall dairy herds using a standardized environmental sampling technique and targeted pooled samples

Mycobacterium avium ssp. paratuberculosis (MAP) is the etiologic agent of Johne's disease, a chronic contagious enteritis of ruminants that causes major economic losses. Several studies, most involving large free-stall herds, have found environmental sampling to be a suitable method for detecting MAP-infected herds. In eastern Canada, where small tie-stall herds are predominant, certain conditions and management practices may influence the survival and transmission of MAP and recovery (isolation). Our objective was to estimate the performance of a standardized environmental and targeted pooled sampling technique for the detection of MAP-infected tie-stall dairy herds. Twenty-four farms (19 MAP-infected and 5 non-infected) were enrolled, but only 20 were visited twice in the same year, to collect 7 environmental samples and 2 pooled samples (sick cows and cows with poor body condition). Concurrent individual sampling of all adult cows in the herds was also carried out. Isolation of MAP was achieved using the MGIT Para TB culture media and the BACTEC 960 detection system. Overall, MAP was isolated in 7% of the environmental cultures. The sensitivity of the environmental culture was 44% [95% confidence interval (CI): 20% to 70%] when combining results from 2 different herd visits and 32% (95% CI: 13% to 57%) when results from only 1 random herd visit were used. The best sampling strategy was to combine samples from the manure pit, gutter, sick cows, and cows with poor body condition. The standardized environmental sampling technique and the targeted pooled samples presented in this study is an alternative sampling strategy to costly individual cultures for detecting MAP-infected tie-stall dairies. Repeated samplings may improve the detection of MAP-infected herds.

Evolutionary implications of mitochondrial genetic variation: mitochondrial genetic effects on OXPHOS respiration and mitochondrial quantity change with age and sex in fruit flies

The ancient acquisition of the mitochondrion into the ancestor of modern-day eukaryotes is thought to have been pivotal in facilitating the evolution of complex life. Mitochondria retain their own diminutive genome, with mitochondrial genes encoding core subunits involved in oxidative phosphorylation. Traditionally, it was assumed that there was little scope for genetic variation to accumulate and be maintained within the mitochondrial genome. However, in the past decade, mitochondrial genetic variation has been routinely tied to the expression of life-history traits such as fertility, development and longevity. To examine whether these broad-scale effects on life-history trait expression might ultimately find their root in mitochondrially mediated effects on core bioenergetic function, we measured the effects of genetic variation across twelve different mitochondrial haplotypes on respiratory capacity and mitochondrial quantity in the fruit fly, Drosophila melanogaster. We used strains of flies that differed only in their mitochondrial haplotype, and tested each sex separately at two different adult ages. Mitochondrial haplotypes affected both respiratory capacity and mitochondrial quantity. However, these effects were highly context-dependent, with the genetic effects contingent on both the sex and the age of the flies. These sex- and age-specific genetic effects are likely to resonate across the entire organismal life-history, providing insights into how mitochondrial genetic variation may contribute to sex-specific trajectories of life-history evolution.

Environmental scan of interprofessional collaborative practice initiatives

Interprofessional collaboration in health care is high on the policy agenda in Canada. There is evidence that governments, academic institutions, regulatory bodies and health services are developing directions, policies and strategies with collaboration in mind. The Ottawa Hospital (TOH) received governmental funding to implement The Ottawa Hospital Inter-Professional Model of Patient Care.Prior to implementing our model, we conducted an environmental scan to identify initiatives related to interprofessional collaboration in clinical settings. A historical method was used to understand the chronological development of interprofessional collaboration within the health field over the last 10 years. Critical browsing was used to search, select and summarize information found on the web. Fifty two documents were critically reviewed; 27 documents were retained for further analysis and inclusion.The information was analyzed according to three main parameters: source, summary and relevance to our project. The five broad themes identified are: promotion, networking, evidence, resources and linkage between interprofessional education and care. This seems an accurate reflection of the current state of this area; there is active promotion and networking, concrete frameworks and funds but few published results regarding the efficacy of implementing IPC in health care organizations. As experience with the approach accumulates, evidence should grow

Monoamine oxidase A gene promoter methylation and transcriptional downregulation in an offender population with antisocial personality disorder

BACKGROUND

Antisocial personality disorder (ASPD) is characterised by elevated impulsive aggression and increased risk for criminal behaviour and incarceration. Deficient activity of the monoamine oxidase A (MAOA) gene is suggested to contribute to serotonergic system dysregulation strongly associated with impulsive aggression and antisocial criminality.

AIMS

To elucidate the role of epigenetic processes in altered MAOA expression and serotonin regulation in a population of incarcerated offenders with ASPD compared with a healthy non-incarcerated control population.

METHOD

Participants were 86 incarcerated participants with ASPD and 73 healthy controls. MAOA promoter methylation was compared between case and control groups. We explored the functional impact of MAOA promoter methylation on gene expression in vitro and blood 5-HT levels in a subset of the case group.

RESULTS

Results suggest that MAOA promoter hypermethylation is associated with ASPD and may contribute to downregulation of MAOA gene expression, as indicated by functional assays in vitro, and regression analysis with whole-blood serotonin levels in offenders with ASPD.

CONCLUSIONS

These results are consistent with prior literature suggesting MAOA and serotonergic dysregulation in antisocial populations. Our results offer the first evidence suggesting epigenetic mechanisms may contribute to MAOA dysregulation in antisocial offenders.

A systematic review of risk factors associated with the introduction of Mycobacterium avium spp. paratuberculosis (MAP) into dairy herds

The objective of this study was to systematically collect and appraise the scientific evidence related to risk factors associated with the introduction of Mycobacterium avium spp. paratuberculosis (MAP) into a herd of cattle. An electronic search was conducted to collect relevant references addressing 2 specific questions: are i) purchasing/introduction of cattle into a herd, and ii) presence of wildlife or domestic animals, risk factors for the introduction of MAP into a herd? The screening was based on titles and abstracts and selected studies were fully analyzed. Seventeen manuscripts published between 1996 and 2011 were ultimately analyzed. Unit of interest was mainly the herd (n = 17). The specific description of the risk factors studied varied between studies. The principal study design was cross-sectional (n = 15). The review indicated that purchase/introduction of animals was an important risk factor and that the importance of wildlife or other domestic species as a mechanism for transmission into a cattle herd was not measurable.

Multiple-locus variable-number tandem-repeat analysis of Francisella tularensis from Quebec, Canada

Francisella tularensis is ubiquitous in the Northern Hemisphere. Yet, little is known about the disease and its ecology within Canada as few serological studies have shown exposure to the disease and fewer case studies have been reported. This report is the first to describe the molecular subtyping of F. tularensis isolates within eastern Canada using multiple-locus variable-number tandem-repeat analysis. From 1998 to 2011, a total of 73 specimens were isolated from unique human and animal sources. As expected, F. tularensis subsp. tularensis AI and F. tularensis subsp. holarctica subtypes were observed, corresponding to the known geographical division within this species. The majority of human isolates (78%) and all animal (hare) isolates were of the more virulent, AI type. Half of the B isolates were isolated from patients living in a region of Quebec where muskrat densities are known to be high. A relatively high level of marker diversity was found, suggestive of multiple introductions of the organism to the region, or more likely ongoing endemicity. There was no evidence of ongoing outbreaks or transmission, and the bulk of cases were likely due to interaction between human activity and the environment (e.g. hunting/trapping activities).

SIGNIFICANCE AND IMPACT OF THE STUDY

This study reveals the diversity of Francisella tularensis in eastern Canada using multiple-locus variable-number tandem-repeat analysis. It was initiated to further the understanding of the species within North America as previous studies elucidating the diversity and phylogeography of the species have consisted mostly of specimens from the United States. Type A tularaemia, the most life-threatening subtype of the species and a Category A biothreat agent, is restricted to North America, and this study serves to broaden the knowledge of the epidemiology and diversity of the organism.

Kind attention and non-judgment in mindfulness-based cognitive therapy applied to the treatment of insomnia: state of knowledge

Psychophysiological insomnia is characterized by acquired sleep difficulties and/or a state of hypervigilance when going to bed. This mental and physiological condition prevents sleep onset regardless of the presence of anxious or depressive disorders. Despite the fact that cognitive behavioural therapies have been shown to be effective for this disorder, some people are not responding to this treatment. It is therefore important to explore new ways of increasing the effectiveness of current treatments. Approaches based on mindfulness, which promote a non-judgemental acceptance of the living experience, are increasingly reported in the literature to be effective in the treatment of various physical and psychological health conditions, being particularly efficient in reducing the stress and discomfort associated with these problems. This article focuses on some cognitive factors associated with maintaining insomnia and suggests that approaches based on mindfulness, through certain action mechanisms, may help to improve sleep. A review of recent studies on the application of mindfulness-based approaches to treat insomnia is hereby presented. Avenues for future research to improve insomnia treatment protocols based on mindfulness are suggested.

Health-promoting vending machines: evaluation of a pediatric hospital intervention

PURPOSE

Taking advantage of a natural experiment made possible by the placement of health-promoting vending machines (HPVMs), we evaluated the impact of the intervention on consumers' attitudes toward and practices with vending machines in a pediatric hospital.

METHODS

Vending machines offering healthy snacks, meals, and beverages were developed to replace four vending machines offering the usual high-energy, low-nutrition fare. A pre- and post-intervention evaluation design was used; data were collected through exit surveys and six-week follow-up telephone surveys among potential vending machine users before (n=293) and after (n=226) placement of HPVMs. Chi-2 statistics were used to compare pre- and post-intervention participants' responses.

RESULTS

More than 90% of pre- and post-intervention participants were satisfied with their purchase. Post-intervention participants were more likely to state that nutritional content and appropriateness of portion size were elements that influenced their purchase. Overall, post-intervention participants were more likely than pre-intervention participants to perceive as healthy the options offered by the hospital vending machines. Thirty-three percent of post-intervention participants recalled two or more sources of information integrated in the HPVM concept. No differences were found between pre- and post-intervention participants' readiness to adopt healthy diets.

CONCLUSIONS

While the HPVM project had challenges as well as strengths, vending machines offering healthy snacks are feasible in hospital settings.

Factor analysis of the French version of the shorter 12-item Perception of Aggression Scale (POAS) and of a new modified version of the Overt Aggression Scale (MOAS)

Psychiatric staff perceptions of aggression by psychiatric patients may affect the therapeutic relationship between care providers and patients in institutions. Attitudes to and the subjective experience of violence may also differ substantially between members of a single care team. This study seeks to validate the French versions of scales of staff attitudes to and subjective experience of institutional violence: a new, modified version of the Overt Aggression Scale (MOAS) to measure the subjective perception of the frequency of aggression in the ward; and the Perception of Aggression Scale (POAS) to assess attitudes to the expression of violence by psychiatric patients. Frontline staff (n = 362) from eight French-language psychiatric institutions in the province of Quebec were surveyed. Factor analyses were performed to determine the validity of the French-language MOAS and POAS. As expected, a four-factor structure emerged for the MOAS. For the 12-item POAS, a three-factor structure was found: (1) 'Aggression as a dysfunctional/undesirable phenomenon'; (2) 'Aggression as a positive expression'; and (3) 'Aggression as a protective measure'. This study supports use of the French MOAS and POAS in assessing staff attitudes to and subjective experience of aggression in future projects to explore the perception and management of inpatient violence.

Risk factors associated with transmission of Mycobacterium avium subsp. paratuberculosis to calves within dairy herd: a systematic review

BACKGROUND

Paratuberculosis has a worldwide distribution and many countries have implemented control programs to prevent transmission among and within herds. For these programs to be efficient, knowledge of the risk factors involved in transmission is essential.

OBJECTIVES

Systematically review the scientific literature concerning risk factors associated with Mycobacterium avium subsp. paratuberculosis (MAP) transmission to dairy calves.

STUDY DESIGN

Systematic review.

METHODS

An electronic search was done in PubMed and CAB to retrieve references relevant to answer at least 1 of the 5 questions concerning neonatal environment, colostrum, milk, housing of calves, and contact of calves with adult cow feces as risk factors in MAP transmission. A 1st screening was done using titles only, then abstracts, and finally full-length articles were reviewed for relevance. From the articles selected, risk factors and presence of a significant association between these risk factors and MAP transmission were recorded.

RESULTS

Twenty-three articles from 11 different countries and published in 12 different journals were reviewed. The most common study design was cross-sectional (n = 16). The case definition and diagnostic tests used were very variable among studies, but serum ELISA was used in most studies (n = 14). The study unit was the herd in 18 studies.

CONCLUSIONS AND CLINICAL IMPORTANCE

The contact of calves with adult cow feces is the most important risk factor in MAP transmission. The 5 categories of risk factors are linked to one another.

An eastern equine encephalomyelitis (EEE) outbreak in Quebec in the fall of 2008

Eastern equine encephalomyelitis (EEE) was diagnosed in 19 horses and a flock of emus in the province of Quebec in fall 2008. The EEE virus caused unusual gross lesions in the central nervous system of one horse. This disease is not usually present in Quebec and the relation between the outbreak and favorable environmental conditions that summer are discussed.

Characterization of mononuclear cells remaining in the leukoreduction system chambers of apheresis instruments after routine platelet collection: a new source of viable human blood cells

BACKGROUND

The yield of white blood cells (WBCs) extracted from whole-blood leukoreduction filters can be affected by the storage conditions and delay before filtration. Platelets (PLTs) collected with apheresis instruments (Trima Accel, Gambro BCT) are leukoreduced during the procedure on a fluidized particle bed in a leukoreduction chamber (LRS chamber). In this report, the residual cell content of these LRS chambers was characterized to determine whether it would be a valuable source of viable human blood cells.

STUDY DESIGN AND METHODS

The content of LRS chambers was eluted by gravity, and peripheral blood mononuclear cells (PBMNCs) were purified on a Ficoll-Paque gradient. Analyses were performed before and after freezing. Proportions of CD3+, CD14+, CD16+, CD19+, CD34+, and CD45+ cells were determined by flow cytometry. The frequency of T cells expressing CD4, CD8, and CD27 and of B cells expressing immunoglobulin G (IgG), IgM, and CD27 was also determined.

RESULTS

LRS chambers held approximately 10(9) CD45+ cells representing the normal proportions of CD3+, CD14+, CD16+, and CD19+ cell populations of PBMNCs. A small fraction of these CD45+ cells were CD34+CD38+ cells (0.3 +/- 0.2%). The viability of these cells, measured before and after freezing, was more than 95 percent.

CONCLUSION

The residual cell content of Trima Accel LRS chambers recovered after PLT collection is a good source of viable monocytes and lymphocytes. These PBMNCs, containing CD3+, CD14+, CD16+, CD19+, and CD34+ cells can be frozen to prepare cell banks, which opens new avenues for utilization in several physiologic studies or even in cellular therapy applications.

A new memory CD27-IgG+ B cell population in peripheral blood expressing VH genes with low frequency of somatic mutation

In humans, up to 40% of peripheral B cells express CD27 and have hypermutated variable regions in their Ig genes. The CD27+ B cells are considered to be derived from germinal center following specific antigenic stimulation. Actually, somatic hypermutation in Ig genes and CD27 expression are hallmarks of memory B cells. However, the blood IgM+ IgD+ CD27+ B cells were recently associated to splenic marginal zone B cells and proposed to be a subset distinct from germinal center-derived memory B cells showing premutated Igs. The results presented herein further weaken this bona fide association because B cells expressing surface IgG, but not CD27, were found in human blood. Representing 1-4% of all peripheral B cells and approximately 25% of the IgG+ blood B cells, this population expressed mutated IgG genes showing antigenic selection characteristics but with lower mutation frequencies than that of CD27+ IgG+ B cells. However, their morphology and phenotype were similar to that of CD27+ IgG+ cells. Interestingly, the proportion of IgG2 over IgG3 transcripts was opposite in CD27- IgG+ and CD27+ IgG+ cells, suggesting distinct functions or origins. Overall, these findings extend the memory B cell reservoir beyond the CD27+ compartment and could provide further insights into B cell disorders of unknown etiology.

Detection of depression and anxiety disorders by home care nurses

Several studies have reported that psychiatric disorders, mainly depression and anxiety disorders, were masked and undiagnosed among older adults, particularly frail elderly. This phenomenon could have a significant impact on elderly quality of life. In this study, we assessed the utility of three measures for detecting mental health disorders among frail elderly receiving home care services: (1) the PRIME-MD; (2) a standard psychological distress measure (PDI-29), and (3) the health care case manager'sa priori judgment on the subject's mental health status. Results obtained by home care nurses were compared to those obtained by clinical psychologists using a structured diagnostic interview (SCID for DSM-IV). The study was conducted in two community health service centres. During the study's period, all patients in the health care workers' caseload without cognitive impairment and not reporting significant stressful life events during the six-week period preceding the interview (n = 315) were asked to participate in the study. Results showed that 42.9% of the volunteers that agreed to meet a psychologist at home (n = 177) had a current SCID-IV diagnosis. The specificity of the PRIME-MD test performed by nurses was 83.8% and its sensitivity was 41.7%. The correct classification rate was 66.7%. Results indicated that the PDI-29 items showed better performance characteristics than the PRIME-MD in identifying current cases. The specificity of the PDI-29 was 59.0% and its sensitivity was 73.6%. These results lead us to the conclusion that the PRIME-MD, previously proposed by Spitzer, R.L., Williams, J.B., Kroenke, K., Linzer, M., DeGruy, F.V. 3rd, Hahn, S.R., et al. (1994, Utility of a new procedure for diagnosing mental disorders in primary care. The PRIME-MD 1000 study. Journal of the American Medical Association, 272 (22), 1749-1756.) to help physicians in primary care clinics, could be less appropriate than the PDI-29 when used by home care nurses in identifying undiagnosed mental health disorders in frail older adults living at home. Moreover, this study showed that the health care case manager'sa priori judgment on the care receiver's mental health status is not sufficient in identifying frail elderly mental health services needs. A two-stage screening procedure is proposed to help home care nurses.

Infrarenal Aortic Stenosis: Value of Stent Placement after Percutaneous Transluminal Angioplasty Failure

PURPOSE

To evaluate the long-term clinical and hemodynamic effectiveness of aortic stent placement in cases of failure of intended infrarenal percutaneous transluminal aortic angioplasty (PTAA).

MATERIALS AND METHODS

Fifty-three patients who underwent technically successful PTAA were compared with 24 patients who underwent aortic stent placement because of PTAA failure (19 patients) or ulcerated lesions (five patients) that otherwise would have been treated surgically because of the embolization hazard associated with PTAA alone. Clinical patency was defined as the absence or improvement of symptoms after the intervention. Hemodynamic patency was defined as a normal Doppler waveform in the common femoral arteries, an ankle-brachial index greater than 0.95, or the absence of a thigh-brachial pressure gradient.

RESULTS

Three-year clinical and hemodynamic patency rates, respectively, were 85% and 79% for PTAA and 69% and 43% for aortic stent placement. No morbidity was encountered. With use of the Cox proportional hazards model, two significant risk factors were retained for restenosis: unchanged smoking habit (P =.04) and small dilatation diameter (P =.001). Aortic stent placement, performed in patients with a smaller aortic diameter (10.3 vs. 12.7 mm for PTAA), appeared to be a predictive factor for restenosis by using univariate analysis. By using the Cox proportional hazards model, however, the restenosis rates after PTAA and aortic stent placement were not significantly different.

CONCLUSION

When aortic diameter is taken into consideration, there is no evidence that clinical outcome after secondary aortic stent placement would be poorer than technically successful PTAA.

Late (> 48 hr) myocardial infarction after PTCA: clinical and angiographic characteristics of infarction related or not to the angioplasty site

Since late myocardial infarctions after percutaneous coronary interventions have not been well characterized, we intended to evaluate the characteristics of myocardial infarctions occurring > 48 hr after balloon angioplasty of native coronary arteries or saphenous vein grafts. The Montreal Heart Institute database (1985-1996) was interrogated for all patients readmitted with a diagnosis of MI more than 48 hr after successful percutaneous transluminal coronary angioplasty (PTCA). We compared the clinical, procedural, and angiographic variables between MIs related or not to the index PTCA site. One hundred and ninety-three patients presented with late myocardial infarction (MI) following balloon angioplasty. The median time elapsed between PTCA and MI was 55 days compared to 968 days when MI was unrelated to the PTCA site. MIs related to the PTCA site were more likely non-Q-wave (76% vs. 35%, P = 0.0001) with less marked CK-MB rise. Angiography showed less complex lesions (63% vs. 90%, P = 0.001) and better thrombolysis in myocardial infarction (TIMI) grade flow (TIMI II to III, 66% vs. 56%, P = 0.01) when the culprit lesion was at the PTCA site. Independent predictors of MI at the PTCA site were vein graft dilation, female sex, and residual stenosis post-PTCA. Myocardial infarctions occurring late after PTCA have a distinct time course and present specific characteristics according to their relationship or not to the previously dilated site.

Randomized trial comparing intravenous nitroglycerin and heparin for treatment of unstable angina secondary to restenosis after coronary artery angioplasty

BACKGROUND

The treatment of unstable angina targets the specific pathophysiological thrombotic process at the site of the active culprit lesion. In unstable angina due to a restenotic lesion, smooth muscle cell proliferation and increased vasoreactivity may play a more important role than thrombus formation. Therefore, the relative benefits of nitroglycerin and heparin might differ in unstable angina associated with restenosis compared with classic unstable angina.

METHODS AND RESULTS

We randomized 200 patients hospitalized for unstable angina within 6 months after angioplasty (excluding those with intracoronary stents) to double-blind administration of intravenous nitroglycerin, heparin, their combination, or placebo for 63+/-30 hours. Recurrent angina occurred in 75% of patients in the placebo and heparin-alone groups, compared with 42.6% of patients in the nitroglycerin-alone group and 41.7% of patients in the nitroglycerin-plus-heparin group (P<0.003). Refractory angina requiring angiography occurred in 22.9%, 29.2%, 4. 3%, and 4.2% of patients, respectively (P<0.002). The odds ratios for being event free were 0.24 (95% CI, -0.13 to 0.45, P=0.0001) for nitroglycerin versus no nitroglycerin and 0.98 (95% CI, -0.55 to 1. 73, P=NS) for heparin versus no heparin. No patient died or suffered myocardial infarction.

CONCLUSIONS

Intravenous nitroglycerin is highly effective in preventing adverse ischemic events (recurrent or refractory angina) in patients with unstable angina secondary to restenosis, whereas heparin has no effect.

Endothelial cell retraction is induced by PAK2 monophosphorylation of myosin II

The p21-activated kinase (PAK) family includes several enzyme isoforms regulated by the GTPases Rac1 and Cdc42. PAK1, found in brain, muscle and spleen, has been implicated in triggering cytoskeletal rearrangements such as the dissolution of stress fibers and reorganization of focal complexes. The role of the more widely distributed PAK2 in controlling the cytoskeleton has been less well studied. Previous work has demonstrated that PAK2 can monophosphorylate the myosin II regulatory light chain and induce retraction of permeabilized endothelial cells. In this report we characterize PAK2's morphological and biochemical effect on intact endothelial cells utilizing microinjection of constitutively active PAK2. Under these conditions we observed a modification of the actin cytoskeleton with retraction of endothelial cell margins accompanied by an increase in monophosphorylation of myosin II. Selective inhibitors were used to analyze the mechanism of action of PAK2. Staurosporine, a direct inhibitor of PAK2, largely prevented the action of microinjected PAK2 in endothelial cells. Butanedione monoxime, a non-specific myosin ATPase inhibitor, also inhibited the effects of PAK2 implicating myosin in the changes in cytoskeletal reorganization. In contrast, KT5926, a specific inhibitor of myosin light chain kinase was ineffective in preventing the changes in morphology and the actin cytoskeleton. The additional finding that endogenous PAK2 associates with myosin II is consistent with the proposal that cell retraction and cytoskeletal rearrangements induced by microinjected PAK2 depend on the direct activation of myosin II by PAK2 monophosphorylation of the regulatory light chain.

Value of exercise electrocardiography in the detection of restenosis after coronary angioplasty in patients with one-vessel disease

Exercise treadmill testing (ETT) is considered an unreliable method for detection of restenosis after percutaneous transluminal coronary angioplasty (PTCA). The studies on which this belief is based have used quantitative coronary angiography (QCA) as a reference. The inherent limitations of angiography have been demonstrated by intravascular ultrasound (IVUS). To determine the value of ETT for detecting restenosis when IVUS criteria are used to define restenosis, we studied 29 patients with angiographically documented 1-vessel coronary disease (<35% stenosis in all nondilated segments) who underwent angioplasty. ETT was performed < or =2 weeks before follow-up angiography and IVUS imaging. Only patients without any abnormalities precluding an accurate reading of the ST segment during ETT were included. Restenosis was defined as a > or =50% diameter stenosis by QCA criteria and as a cross-sectional area narrowing of > or =75% by IVUS. The ETT was positive in 12 patients and restenosis was documented by QCA and IVUS in 38% and 48% of cases, respectively. Sensitivity, specificity, and positive and negative predictive values of ETT when QCA was used as a reference were 55%, 67%, 50%, and 71%, respectively. This corresponded to an accuracy of 62% when compared with QCA. Sensitivity, specificity, and positive and negative predictive values were 79%, 93%, 92%, and 82% when ETT was compared with IVUS, with an accuracy of 86% (p = 0.002). Thus, ETT is a reliable noninvasive method for detecting the presence of restenosis after PTCA in patients with 1-vessel coronary artery disease. The presence of > or =75% cross-sectional narrowing shown by IVUS is well correlated with > or =1-mm ST-segment depression at follow-up ETT after PTCA.

Persistent infection of human oligodendrocytic and neuroglial cell lines by human coronavirus 229E

Human coronaviruses (HuCV) cause common colds. Previous reports suggest that these infectious agents may be neurotropic in humans, as they are for some mammals. With the long-term aim of providing experimental evidence for the neurotropism of HuCV and the establishment of persistent infections in the nervous system, we have evaluated the susceptibility of various human neural cell lines to acute and persistent infection by HuCV-229E. Viral antigen, infectious virus progeny and viral RNA were monitored during both acute and persistent infections. The astrocytoma cell lines U-87 MG, U-373 MG, and GL-15, as well as neuroblastoma SK-N-SH, neuroglioma H4, and oligodendrocytic MO3.13 cell lines, were all susceptible to an acute infection by HuCV-229E. The CHME-5 immortalized fetal microglial cell line was not susceptible to infection by this virus. The MO3.13 and H4 cell lines also sustained a persistent viral infection, as monitored by detection of viral antigen and infectious virus progeny. Sequencing of the S1 gene from viral RNA after approximately 130 days of infection showed two point mutations, suggesting amino acid changes during persistent infection of MO3.13 cells but none for H4 cells. Thus, persistent in vitro infection did not generate important changes in the S1 portion of the viral spike protein, which was shown for murine coronaviruses to bear hypervariable domains and to interact with cellular receptor. These results are consistent with the potential persistence of HuCV-229E in cells of the human nervous system, such as oligodendrocytes and possibly neurons, and the virus's apparent genomic stability.

Acute and persistent infection of human neural cell lines by human coronavirus OC43

Human coronaviruses (HuCV) are recognized respiratory pathogens. Data accumulated by different laboratories suggest their neurotropic potential. For example, primary cultures of human astrocytes and microglia were shown to be susceptible to an infection by the OC43 strain of HuCV (A. Bonavia, N. Arbour, V. W. Yong, and P. J. Talbot, J. Virol. 71:800-806, 1997). We speculate that the neurotropism of HuCV will lead to persistence within the central nervous system, as was observed for murine coronaviruses. As a first step in the verification of our hypothesis, we have characterized the susceptibility of various human neural cell lines to infection by HuCV-OC43. Viral antigen, infectious virus progeny, and viral RNA were monitored during both acute and persistent infections. The astrocytoma cell lines U-87 MG, U-373 MG, and GL-15, as well as neuroblastoma SK-N-SH, neuroglioma H4, oligodendrocytic MO3.13, and the CHME-5 immortalized fetal microglial cell lines, were all susceptible to an acute infection by HuCV-OC43. Viral antigen and RNA and release of infectious virions were observed during persistent HuCV-OC43 infections ( approximately 130 days of culture) of U-87 MG, U-373 MG, MO3.13, and H4 cell lines. Nucleotide sequences of RNA encoding the putatively hypervariable viral S1 gene fragment obtained after 130 days of culture were compared to that of initial virus input. Point mutations leading to amino acid changes were observed in all persistently infected cell lines. Moreover, an in-frame deletion was also observed in persistently infected H4 cells. Some point mutations were observed in some molecular clones but not all, suggesting evolution of the viral population and the emergence of viral quasispecies during persistent infection of H4, U-87 MG, and MO3.13 cell lines. These results are consistent with the potential persistence of HuCV-OC43 in cells of the human nervous system, accompanied by the production of infectious virions and molecular variation of viral genomic RNA.

Quantitative angiographic assessment of coronary anastomoses performed without cardiopulmonary bypass

BACKGROUND

The quality of the anastomosis performed during coronary artery bypass grafting without cardiopulmonary bypass is a current concern, and myocardial wall restraining devices have been designed to optimize results. A quantitative angiographic analysis was performed to assess coronary anastomoses performed on beating hearts.

METHODS

We studied 34 patients who underwent coronary artery bypass grafting without cardiopulmonary bypass between February 1996 and April 1997. The left internal thoracic artery was anastomosed to the left anterior descending coronary artery in all patients. Coronary angiograms were performed 4 +/- 2 days after the operation. The diameter of the anastomoses was quantified by computer-assisted analysis of grafts and native coronary arteries at the toe and heel of the anastomosis.

RESULTS

Five of the patients who underwent coronary artery bypass without a stabilizer (n = 20) had stenoses of the internal thoracic artery grafted to the left anterior descending coronary artery of more than 50% at the level of the anastomosis proper, 3 had stenoses at the heel of the coronary anastomosis, and 5 had stenoses at the toe. One of the patients in whom a stabilizer was used (n = 14) had a stenosis of more than 50% at the anastomosis, and 1 had stenosis at the heel. Eight patients in whom the anastomoses were performed without stabilization (8/20, 40%) had stenoses of more than 50%, whereas there was only 1 stenosis of more than 50% of coronary luminal diameter among the patients in whom the operation was performed with a stabilizer (P =.02).

CONCLUSION

The quantitative angiographic evaluation suggests that left internal thoracic artery graft to left anterior descending coronary artery anastomoses have a lesser degree of intraluminal stenosis when performed with the use of a myocardial wall stabilizer.

Effects of probucol on vascular remodeling after coronary angioplasty. Multivitamins and Protocol Study Group

BACKGROUND

We have shown that probucol reduces restenosis after balloon angioplasty. Whether probucol acted via prevention of neointimal formation or improvement in vascular remodeling could not be addressed by angiography and required the use of intravascular ultrasound (IVUS).

METHODS AND RESULTS

Beginning 30 days before angioplasty, 317 patients were randomly assigned to receive probucol, multivitamins, combined treatment, or placebo. Patients were then treated for 6 months after angioplasty. IVUS examination was performed immediately after angioplasty and at follow-up in 94 patients (111 segments). The cross section selected for serial analysis was the one at the angioplasty site with the smallest lumen area at follow-up. In the placebo group, lumen area decreased by -1. 21+/-1.88 mm2 at follow-up, and wall area and external elastic membrane (EEM) area increased by 1.50+/-2.50 and 0.29+/-2.93 mm2, respectively. Change in lumen area, however, correlated more strongly with the change in EEM area (r=0.53, P=0.002) than with the change in wall area (r=-0.13, P=0.49). Lumen loss was -1.21+/-1.88 mm2 for placebo, -0.83+/-1.22 mm2 for vitamins, -0.25+/-1.17 mm2 for combined treatment, and -0.15+/-1.70 mm2 for probucol alone (P=0.002 for probucol, P=0.84 for vitamins). Change in wall area was similar for all groups. EEM area increased by 0.29+/-2.93 mm2 for placebo, 0. 09+/-2.33 mm2 for vitamins only, 1.17+/-1.61 mm2 for combined treatment, and 1.74+/-1.80 mm2 for probucol only (P=0.005 for probucol).

CONCLUSIONS

Lumen loss after balloon angioplasty is due to inadequate vessel remodeling in response to neointimal formation. Probucol exerts its antirestenotic effects by improving vascular remodeling after angioplasty.

Semi-fixed-length motion vector coding for H.263-based low bit rate video compression

We present a semi-fixed-length motion vector coding method for H.263-based low bit rate video compression. The method exploits structural constraints within the motion field. The motion vectors are encoded using semi-fixed-length codes, yielding essentially the same levels of rate-distortion performance and subjective quality achieved by H.263's Huffman-based variable length codes in a noiseless environment. However, such codes provide substantially higher error resilience in a noisy environment.

An efficient computation-constrained block-based motion estimation algorithm for low bit rate video coding

We present an efficient computation constrained block-based motion vector estimation algorithm for low bit rate video coding that yields good tradeoffs between motion estimation distortion and number of computations. A reliable predictor determines the search origin, localizing the search process. An efficient search pattern exploits structural constraints within the motion field. A flexible cost measure used to terminate the search allows simultaneous control of the motion estimation distortion and the computational cost. Experimental results demonstrate the viability of the proposed algorithm in low bit rate video coding applications. The resulting low bit rate video encoder yields essentially the same levels of rate-distortion performance and subjective quality achieved by the UBC H.263+ video coding reference software. However, the proposed motion estimation algorithm provides substantially higher encoding speed as well as graceful computational degradation capabilities.