Update on Cold-Induced Injuries

Cold-induced injuries are a major challenge for burn surgeons, leading to significant sequelae for the patients including amputations, long-term disability, and death. Rapid assessment and diagnosis are essential for optimal outcomes. Various therapies have emerged to improve outcomes. Topical, oral, and intravenous agents have shown to minimize the impact of cold-induced injuries. Thrombolytics have shown the greatest promise in improving tissue perfusion outcomes in cold-induced injuries. This article provides an update on the evidence-based assessment and management of cold-induced injuries, as well as reviews outcomes and future directions of this challenging pathology.

A Systematic Review on Airbag-Induced Burns

Airbags significantly reduce fatalities and injuries in automobile crashes, but they have been found to be associated with burns. Specifically, airbags can cause burns through thermal or chemical mechanisms and commonly affect the arms, hands, face, and eyes. While most airbag-induced burns are minor, some may cause unfavorable outcomes. Our study aimed to systematically review airbag-induced burns to assess etiology, type, and treatment of these injuries. A systematic review of case reports pertaining to airbag-induced cutaneous and ocular burns was conducted. Data reviewed included type/location of burns, severity of burn, total number of patients, treatment, complications, and outcome after treatment. We identified 21 case reports that met our inclusion criteria with a total of 24 patients reported in the studies. Of the studies identified, 38% were chemical burns and 25% were thermal burns. Most commonly the upper extremities were burned in 42% of cases, followed by eyes (25%) and face (21%). Most burns identified were superficial partial thickness (58%). Treatment outcomes were good for cutaneous burns, with 95% healing without complication. However, ocular injuries lead to permanent impaired eye function in 71% of cases. In our systematic review, we highlighted the common risk factors, prognosis, and treatment for thermal, chemical, and ocular burns. Airbag-induced burns have a relatively good prognosis but must be recognized and treated immediately to reduce the risk of serious sequelae.

Characteristics and Academic Productivity Among Pediatric Plastic Surgeons in the United States

BACKGROUND

The characteristics that predispose plastic surgeons to a career in pediatric plastic surgery remain unclear. Therefore, the aim of this study is to analyze the characteristics of current pediatric plastic surgeons and to determine their academic productivity.

METHODS

Pediatric plastic surgeons were identified through an internet search of all academic children's hospitals affiliated with an Accreditation Council for Graduate Medical Education-accredited integrated or independent plastic surgery program. Demographics, training background, institutional and leadership positions, and academic productivity were determined.

RESULTS

A total of 304 pediatric plastic surgeons were identified. The majority of pediatric plastic surgeons were white (n = 217, 71.8%) males (n = 235, 77.6%). Clinical fellowships were completed by 86.8% (n = 263) of the cohort, with craniofacial (n = 181, 59.7%) being the most common followed by hand (n = 54, 17.8%); 41.1% had clinical fellowship training at 10 institutions, with the top 3 most represented programs being University of Pennsylvania (n = 19, 6.2%), University of California-Los Angeles (n = 16, 5.3%), and Harvard University (n = 15, 4.9%); 25.7% (n = 78) held leadership positions within their institutions. A significant higher academic productivity was found among research fellowship-trained surgeons, chiefs of pediatric plastic surgery, fellowship directors, and members of departments of plastic surgery. Those who completed an independent residency had a significant higher H-index and number of citations.

CONCLUSION

Pediatric plastic surgery is represented by surgeons of diverse training background. An elite cohort of programs has trained the most pediatric plastic surgeons. Lastly, high academic productivity was found to be correlated with certain demographic and leadership variables highlighting its impact on career advancement.

Simple actions to support breastfeeding can avoid unwanted weaning in infants younger than 6 months hospitalized for bronchiolitis: A before/after study (Bronchilact II)

BACKGROUND

Admission to hospital with bronchiolitis may adversely affect breastfeeding. Correct advice and support have been pointed out as a determining factor.

OBJECTIVES

We conducted a telephone survey to evaluate a set of actions to promote breastfeeding during hospitalization for acute bronchiolitis.

METHODS

Population: All patients 6 months of age or younger hospitalized with acute bronchiolitis and receiving at least partial breastfeeding were eligible for the study. Patients discharged home whose parents accepted to be contacted by phone were also included.

INTERVENTION

We established a set of actions to promote breastfeeding (posters, flyers, staff training, and equipment) in all pediatric wards attending to these patients.

COMPARISON

This was a cross-sectional study conducted during two epidemic seasons of bronchiolitis in a tertiary care hospital. Data on continued breastfeeding at 3 months (0.5-6; median, range) postdischarge were collected by telephone and compared with the same set of data collected from patients with bronchiolitis in the same setting the year before the intervention.

OUTCOME

We conducted a telephone survey to evaluate whether some actions regarding breastfeeding might diminish the risk of unwanted weaning during hospitalization for bronchiolitis. The primary outcome was the proportion of stopped or reduced breastfeeding at discharge. Secondary objectives were to evaluate whether there were factors associated with breastfeeding modification.

RESULTS

The results of the evaluation before intervention (phase 1) are published by Heilbronner et al. In Phase 1 of our study, 84 patients were included and 43 mothers (51%) reported that breastfeeding was modified by hospitalization of their child: 20.4% stopped, 14% switched to partial breastfeeding, and 16.6% reduced breastfeeding. These mothers stated that causes of breastfeeding disturbances were lack of support and advice (63%), followed by severity of the child's respiratory disease (32%), logistical hospital difficulties (30%), and personal organizational issues (9.3%). The intervention took place in September. After the intervention, 50 patients could be included in the study between October 1and December 31, 2016. Among them, 40 (80%) mothers kept breastfeeding as before, four (8%) stopped, four (8%) switched to partial breastfeeding, and two (4%) reduced breastfeeding without stopping. Bronchiolitis was more severe among patients with altered breastfeeding in terms of ventilatory support.

CONCLUSION

Bronchiolitis is a high-risk event for breastfeeding disruption but interventions to promote breastfeeding might help to prevent the risk of unwanted weaning. More severe bronchiolitis probably poses the highest risk of weaning and the need for supplementary nutrition.

Neutrophil Extracellular Traps Drive Mitochondrial Homeostasis in Tumors to Augment Growth

Neutrophil infiltration and neutrophil extracellular traps (NET) in solid cancers are associated with poorer prognosis, but the mechanisms are incompletely understood. We hypothesized that NETs enhance mitochondrial function in tumor cells, providing extra energy for accelerated growth. Metastatic colorectal cancer tissue showed increased intratumoral NETs and supranormal preoperative serum MPO-DNA, a NET marker. Higher MPO-DNA correlated with shorter survival. In mice, subcutaneous tumor implants and hepatic metastases grew slowly in PAD4-KO mice, genetically incapable of NETosis. In parallel experiments, human cancer cell lines grew slower in nu/nu mice treated with DNAse, which disassembles NETs. PAD4-KO tumors manifested decreased proliferation, increased apoptosis, and increased evidence of oxidative stress. PAD4-KO tumors had decreased mitochondrial density, mitochondrial DNA, a lesser degree of ATP production, along with significantly decreased mitochondrial biogenesis proteins PGC1α, TFAM, and NRF-1. In vitro, cancer cells treated with NETs upregulated mitochondrial biogenesis-associated genes, increased mitochondrial density, increased ATP production, enhanced the percentage of cancer cells with reduced mitochondrial membrane potential, and increased the oxygen consumption rate. Furthermore, NETs increased cancer cells' expression of fission and fusion-associated proteins, DRP-1 and MFN-2, and mitophagy-linked proteins, PINK1 and Parkin. All of which were decreased in PAD4-KO tumors. Mechanistically, neutrophil elastase released from NETs activated TLR4 on cancer cells, leading to PGC1α upregulation, increased mitochondrial biogenesis, and accelerated growth. Taken together, NETs can directly alter the metabolic programming of cancer cells to increase tumor growth. NETs represent a promising therapeutic target to halt cancer progression. SIGNIFICANCE: Neutrophils through the release of NETs facilitate the growth of stressed cancer cells by altering their bioenergetics, the inhibition of which induces cell death.

Implementation research to evaluate an educational intervention for people who inject drugs

Objective

In the context of disseminating harm reduction (HR) programmes in Europe, the Eurosider project aims to study the transferability of an effective educational intervention for people who inject drugs (PWID) to four European countries (Bulgaria, Greece, Portugal and Romania). This intervention, entitled Individually-Tailored Support and Education for Safer Injection (ITSESI), has been shown to reduce HIV-Hepatitis C Virus (HCV) risk practices by offering educational supervision during all phases of the injection sequence, from pre- to post-injection.

Methods

The project employs mixed methods and implementation science. The exploratory first step used qualitative interviews and other available data in each country. The second step consists in implementing and evaluating the intervention using a 6-month study conducted among 300 PWID enrolled in the 4 countries. They are interviewed at baseline and at 6 months. The third step will consist in designing, promoting and disseminating all the tools necessary to transfer ITSESI at the European level.

Results

Results from the exploratory phase highlighted two main determining factors for the feasibility of implementing ITSESI: funding and a repressive legal context. Preliminary results from a quantitative analysis of data from the second step will provide a baseline description of the 300 PWID.

Discussion

Findings to date indicate that an exploratory phase is crucial to adapt and transfer the intervention to local contexts and to evaluate it. More globally, the Eurosider project will 1) help understand each local context to adapt the intervention accordingly; 2) assess the feasibility and effectiveness of ITSESI in different contexts; 3) promote and disseminate tools and training to implement the intervention at the European level.

Key messages

People who inject drugs in European countries report HIV-HCV risk practices and adequate prevention should be provided. The implementation of an innovative educational intervention for people who inject drugs may be one response but requires to take into account contextual factors: funding and repressive drug policy.

Abstract 131: Neutrophil extracellular trap mediate mitochondrial biogenesis in cancer cells to promote growth of metastases

Neutrophils through the release of neutrophil extracellular traps (NETs) in response to surgical stress were shown to be able to capture circulating cancer cells, and in doing so, support the development of metastatic disease. In addition, NETs persist within the tumor microenvironment long after the surgical stress happens. The exact nature of the NETs-tumor interaction and the role that NETs play in dictating the tumor microenvironment is unclear. In vivo, subcutaneous and liver metastasis models of colorectal and hepatocellular cancer were performed in wild type and PAD4 KO mice that lack the ability to form NETs. In vitro, bioenergetics profiles of both HCC and CRC cancer cells were studied after co-culture with NETs, isolated from human and murine neutrophils. We found a 3-fold decrease in the tumor volume of PAD4 KO mice compared to control mice 3 weeks after tumor injection in both subcutaneous and liver metastatic models. PAD4 KO tumors showed significantly decreased neutrophil infiltration and no NET formation within the tumor compared to WT mice. PAD4 KO tumors had decreased proliferation rates and increased apoptosis. In vitro, stressed cancer cells release stress signals such as cytokines, chemokines, and DAMPs (HMGB1 and histones), that enhanced neutrophil migration towards them and subsequently triggered NET formation. In turn, NETs resulted in a 2-fold increase in the expression of mitochondrial biogenesis regulators in cancer cells. Increase mitochondrial mass was observed when treated cancer cells with NETs. A significant increase mitochondrial oxygen consumption rate (OCR) and ATP levels were observed when compared with DNase treatment. Taken together, we suggest that cancer cells help in recruiting NETs which in turn regulates mitochondrial bioenergetics for tumor growth and metastasis.

Citation Format: Hamza Yazdani, Samer Tohme, Eva Roy, Patricia Loughran, Dirk Vander Windth, Hai Huang, Allan Tsung. Neutrophil extracellular trap mediate mitochondrial biogenesis in cancer cells to promote growth of metastases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 131.

High-fidelity simulation in training dental students for medical life-threatening emergency

INTRODUCTION

Any dental surgeon may be faced with a critical life-threatening emergency situation. In our university, all students in dentistry receive a standard course on emergency first aid. The aim of this prospective, comparative, single-centre study was to determine whether additional training on a high-fidelity patient simulator would improve student performance.

METHODS

After approval by an Ethical Committee and written informed consent, the students of the Simulation group (n=42) had full-scale high-fidelity training on a patient simulator SimMan 3G^™ (3 hours by six students). They participated in pairs in two scenarios (airway obstruction, seizures, allergies, vasovagal syncope, asthma, chest pain). The first scenario was simple, and the second was a progression to cardiac arrest. Three months later, the Simulation group and the Control group (n=42) participated in a test session with two scenarios. The primary end point was the score at the test session (with a standardised scoring grill, direct observation and audio-video recording). Data were median and 25%-75% percentiles.

RESULTS

High-fidelity training strongly improved the score on the test obtained by the students of the Simulation group (146 [134-154]) which was much higher (P<.0001) than in the Control group (77 [67-85]). Technical as well as non-technical skills components of the scores were improved. In addition, performances of the Simulation group were increased between the training and the test. Simulation session was very positively assessed by the students.

CONCLUSIONS

The results support the systematic introduction of training to critical life-threatening emergency situations on high-fidelity patient simulators the dentistry curriculum. The impact on clinical practice in the dental office remains to be assessed.

Abstract P3-01-02: Trends in positive predictive values following transition from screen film to digital mammography

Purpose

Our health region converted from screen-film mammography (SFM) to digital mammography (DM) in 2005. DM has several advantages over SFM, including superior contrast resolution, less noise, and opportunities for image optimization through post-acquisition processing; although, the spatial resolution of DM is inferior to SFM. We sought to determine what effect this transition may have had on positive predictive values (PPVs) for malignant and premalignant lesions.

Methods

From our institution's breast biopsy database, we retrospectively reviewed core biopsy results for mammographic calcifications performed in the years 2001-2004 (SFM years) and 2009-2012 (DM years). We subsequently determined the PPV3 (detection of malignancy after biopsy) for each group of years (SFM and DM). We then performed subgroup analysis to calculate PPVs for each of ductal carcinoma in-situ (DCIS) without invasion, DCIS with invasion, and premalignant lesions. Premalignant lesions included atypical ductal hyperplasia, atypical lobular hyperplasia, and lobular carcinoma in-situ.

Results

A total of 4787 biopsies in 4633 patients were reviewed. The comparative detection of cancer after biopsy performed for mammographic calcification between SFM and DM was not statistically significant (PPV3 = 23.5% and 24.0%, respectively; P=.71). Upon further analysis, however, PPV for premalignant lesions increased (SFM=6.6% and DM=8.9%; P&lt;.01) and PPV for DCIS without invasion increased (SFM=15.5% and DM=18.2%; P=.015), while PPV for DCIS with invasion decreased (SFM=8.0% and DM=5.8%; P&lt;.01).

Conclusion

We observed no significant impact on PPV3 for calcifications following the transition from SFM to DM; however, our subgroup analysis suggests that with digital mammography we are now detecting a statistically significantly lower proportion of DCIS with invasion but greater proportions of DCIS without invasion and premalignant lesions. As the natural history of these lower-grade lesions, particularly in the premalignant category, is still not entirely understood, the significance of potentially detecting more of these earlier cancers/precancers is uncertain.

Citation Format: Motiuk DA, Dahl P, Roy E, Docktor B-J, Burrowes P. Trends in positive predictive values following transition from screen film to digital mammography [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-01-02.

Tobacco Use Among Adolescents Entering Quebec Youth Protection Centers

BACKGROUND: Every year between 4,000 and 5,000 adolescents reside in Quebec Youth Protection Centers (YPCs). Many of these adolescents use tobacco products and other psychotropic substances that impact their present and future well-being.

OBJECTIVES: Document the prevalence of tobacco use among youth residing in YPCs and identify associated factors. Describe the measures taken to implement policies for smoke-free environments in YPCs and promote smoking cessation counseling for youth in care.

DESIGN/METHODS: Between July 2008 and May 2009, adolescents aged 14-17 living in six YPCs across Quebec were recruited on a volunteer basis to participate in a surveillance study on health risk behaviors. Data on socio-demographics, lifetime substance use and sexual risk behaviors, as well as certain health consequences related to these behaviors were obtained during structured, face-to-face interviews. An analysis of factors associated with daily tobacco use was carried out.

RESULTS: Data regarding behaviors reported during the year prior to admission were collected among 499 participants (boys: 59%; median age: boys: 16; girls: 15). Lifetime tobacco use was reported by 93% of girls and 91% of boys (median age at first cigarette was 12 years). During the year prior to admission, 15% of youth reported no tobacco use, and 20% smoked occasionally. Two thirds (65%) reported daily tobacco use, with 36% of girls and 43% of boys smoking 10 or more cigarettes a day. In univariate analysis, factors significantly (p&lt;0.05) associated with daily smoking were: school failure or dropping out; family history of problematic alcohol or drug use; precocious initiation of alcohol use before age 13; history of regular use of alcohol or cannabis; problematic drug use (measured by DEP-ADO scale); having 6 or more lifetime sexual partners. Following dissemination of these results, measures were taken to develop a smoke-free policy and implementation plan for YPCs. Health professionals were trained to do brief interventions with all youth smokers entering care. In 2015 the YPC presented a brief to the provincial parlimentary committee on the Tobacco Act to support adoption of smoke-free policies for all health establishments in Québec.

CONCLUSION: Daily tobacco use is very prevalent among adolescents entering YPCs and the majority report problematic use of other psychoac-tive substances. Youth entering care merit screening for tobacco and drug use so that appropriate counseling can be initiated. Promoting policies that encourage smoke-free environments in child protection centers for both youth and the professionals working with them may greatly improve the chances for youth to live tobacco-free.

Prevalence of Anaplasma phagocytophilum in small rodents in France

Anaplasma phagocytophilum is an emerging zoonotic tick-borne pathogen affecting a wide range of mammals. Rodents are suspected to be natural reservoirs for this bacterium, but their role in the epidemiologic cycles affecting domestic animals and wild ungulates has not been demonstrated. This study aimed to improve our knowledge on A. phagocytophilum prevalence in Apodemus sylvaticus, A. flavicollis and Myodes glareolus using data collected in 2010 in one area in eastern France and in 2012-2013 in two others areas in western France. Rodents were captured in each site and infection was tested using qualitative real-time PCR assays on either blood or spleen samples. Prevalence showed high variability among sites. The highest prevalence was observed in the most eastern site (with an average infection rate of 22.8% across all species), whereas no rodent was found to be PCR positive in the south-west site and only 6.6% were positive in the north-west of France. Finally, a significant increase in prevalence was observed in autumn samples compared to spring samples in the north-west, but no change was found in the other two sites.

A microfluidic electrochemical biosensor based on multiwall carbon nanotube/ferrocene for genomic DNA detection of Mycobacterium tuberculosis in clinical isolates

Herein we present a microfluidic-multiplexed platform that integrates electrochemical sensors based on carbon nanotubes associated with ferrocene as redox marker (carbon nanotube (CNT)/ferrocene) for direct detection of pathogenic viral DNA from Hepatitis C and genomic DNA from Mycobacterium tuberculosis in clinical isolates. By operating the fluidic device under high flow (150 μl/min), the formation of a very thin depletion layer at the sensor surface (δS = 230 nm) enhances the capture rate up to one DNA strand per second. By comparison, this capture rate is only 0.02 molecule/s in a static regime without flow. This fluidic protocol allows thus enhancing the limit of detection of the electrochemical biosensor from picomolar in bulk solution to femtomolar with a large dynamic range from 0.1 fM to 1 pM. Kinetics analysis also demonstrates an enhancement of the rate constant of electron transfer (kS) of the electrochemical process from 1 s(-1) up to 6 s(-1) thanks to the geometry of the miniaturized fluidic electrochemical cell. This microfluidic device working under high flow allows selective direct detection of a Mycobacterium tuberculosis (H37Rv) rpoB allele from clinical isolate extracted DNA. We envision that a microfluidic approach under high flow associated with a multiwall CNT/ferrocene sensor could find useful applications as the point-of-care for multi-target diagnostics of biomarkers in real samples.

High hepatitis C virus prevalence and incidence among Canadian intravenous drug users

We used data and leftover samples collected through the SurvUDI network to describe the epidemiology of hepatitis C virus (HCV) infection among injection drug users (IDUs) in Eastern Central Canada. Among the 1380 selected IDUs, having participated twice or more between 1997 and 2003, the overall HCV prevalence rate was 60.4% (95% confidence interval [CI]: 57.7-63.0%). Among the 543 initially uninfected participants, the HCV incidence rate was 27.1 per 100 person-years (95% CI: 23.4-30.9 per 100 person-years). Independent predictors of seroconversion, identified among 359 participants, were age, injecting for a year or less, injecting with a syringe previously used by someone else, injecting most often cocaine, engaging in prostitution, and being recruited in a major urban centre. The HCV epidemic severely affects IDUs in this area. Actions to prevent HCV transmission, such as distribution of sterile injection equipment, have to be reinforced. Special efforts have to be targeted towards starting IDUs.

[Pulmonary bilharziosis due to Schistosoma haematobium: pitfalls of species diagnosis. A case report from Libreville, Gabon]

The purpose of this report is to describe a case of pulmonary schistosomiasis treated at la Fondation Jeanne Ebori in Libreville, Gabon. This case is exceptional due to the rarity of the disease and the schistosomiasis agent involved. The patient was a 47-year-old woman who presented with recurrent right-sided pneumonia 6 months after initial hospitalization and nonspecific antimicrobial therapy. Her general status was altered by hyperthermia, right chest pain, and repetitive bouts of hemoptysia. Because etiological diagnosis could not be achieved and clinical condition was deteriorating, the decision was taken to perform exploratory thoracotomy. Based on operative findings, medial and lower lobectomy was performed. Histological examination demonstrated granulomatous inflammatory lesions due to bilharziosis. Infection was attributed to Schistosoma haematobium that is the most common agent in pulmonary localizations. However Ziehl coloration raised the possibility of involvement of Schistosoma intercalatum that has never been observed in the lung and of a hybrid species. Natural hybridization between S. haematobium and S. intercalatum and the presence of active transmission of the Schistosoma hybrid has been suspected in Gabon.

HIV risk profile of male street youth involved in survival sex

OBJECTIVES

To compare HIV risk factors of male street youth involved in survival sex with those of their never involved peers and to describe the sexual activities of the involved youths.

METHODS

From 2001 to 2003, street youth aged 14-23 years were recruited from street youth agencies in Montreal, Canada. Information was collected on sociodemographic characteristics, substance use, and sexual behaviours. Involvement in survival sex was defined as having ever exchanged sex for money, gifts, drugs, shelter, or other needs. Logistic regression was used to identify HIV risk factors associated with involvement in survival sex.

RESULTS

Among the 542 male participants recruited, 27.7% reported involvement in survival sex. HIV risk factors independently associated with such involvement were injection drug using partners (modulated by length of homelessness), unprotected oral sex with male partners, steroid injection, history of sexual abuse, and drug injection. Among involved youths, 32.0% had only female clients, 41.3% only male clients, and 26.7% had clients of both sexes. Unprotected sexual activities were common with clients. However, even more risks were taken with non-commercial sexual partners.

CONCLUSIONS

Male street youth involved in survival sex are at higher risk for HIV than their non-involved peers not only because of their unprotected commercial sexual activities. They have multiple other HIV risks related to non-commercial sexual activities, drug injection, and sexual abuse. All these risks need to be addressed when providing sexual health interventions for this population.

Characteristics of adolescent street youth with a history of pregnancy

This study examines characteristics of adolescent street youth with histories of pregnancy and documents important factors that merit consideration when providing global sexual health care.

STUDY OBJECTIVE

To determine social and behavioral factors associated with a history of pregnancy among adolescent street youth.

DESIGN, SETTING, PARTICIPANTS

In a prospective cohort study, female adolescent street youth (14-19 years) ever pregnant (AEP) were compared with adolescents never pregnant (ANP) using data from baseline questionnaires.

RESULTS

Among the 225 participants, 41.8% were ever pregnant. Both groups were similar with respect to age (mean 17.8 years) and other socio-economic characteristics. However, AEP were more likely to have been kicked out of home (62.8% vs. 47.3%, P=0.022) and to have run away (78.7% vs. 64.9%, P=0.025) and were homeless younger (mean age: 13.9 vs. 14.7 years, P=0.011) and since a longer period (mean: 4.0 vs. 3.0 years, P=0.001). Both groups had problematic alcohol and drug use: 31.3% had a CAGE score >2; 72.2% had a DAST score >6. Almost half (44.0%) had ever injected drugs and AEP were younger at initiation into drug injection (15.2 years vs. 16.0 years, P=0.049). More AEP had experienced intra-familial or extra-familial sexual abuse (71.3% vs. 56.5%, P=0.024), and had had more than one abuser (71.6% vs. 50.0%, P=0.009). Among those abused by family members, abuse occurred at an earlier age for AEP (mean age: 7.4 vs. 8.9 years, P=0.090) and more AEP reported severe abuse: vaginal penetration (62.2% vs. 26.7%, P=0.004) and anal penetration (29.7% vs. 3.3%, P=0.005).

CONCLUSIONS

Histories of severe sexual abuse and early injection drug use are extremely frequent in ever pregnant street adolescents. These factors need to be addressed when planning global health care and sexual health education.

Rett syndrome as a minicolumnopathy

OBJECTIVE

Rett syndrome is a progressive neurological disorder affecting primarily females. It is characterized by the early regression of acquired language, cognitive functions, social skills, and purposeful hand function. Patients with Rett syndrome are often misdiagnosed as autistic. Recent reports of minicolumnar abnormalities in the brains of autistic and Asperger's syndrome prompted us to search for similar pathology in Rett syndrome.

MATERIAL

The patient population consisted of 5 Rett syndrome patients (mean age = 14.4 +/- 4.0 years) and 17 controls (mean age = 14.6 +/- 9.5 years). Tissue was celloidin embedded, sectioned at 35 um and Nissl stained. Images (100x) were taken from Brodmann's areas 9, 21, and 22 from layer III of the left hemisphere.

METHOD

Columnar width measurements for these images were obtained with computerized image analysis using previously published algorithms. Each area was analyzed separately with univariate ANOVA, including diagnosis as a fixed factor and age (linear and quadratic terms), and sex as covariates.

RESULTS

Diagnosis dependent effects were statistically significant only in area 21 (p = 0.009) even when taking into account a Bonferroni correction for the multiple comparisons.

CONCLUSION

Both the regional nature of the changes as well as differences in mean cell spacing differentiates the abnormal minicolumnar morphometry of Rett syndrome from that of autism.

Risk behaviours and prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae genital infections among Montreal street youth

We estimated the prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae genital tract infections among 302 Montreal street youth (223 boys) and identified associated risk factors. Study participants, 14-25 years old (average 20.9 years), meeting specific criteria for homelessness, were recruited in street youth agencies. Participation included a structured interview and provision of a urine specimen. Among sexually active youth, (n = 300) 30.0% had more than five heterosexual partners and 13.0% had at least one homosexual partner (last year), 10.7% had received money in exchange for sex (last six months) and 47.0% reported sexual relations resulting in pregnancy (lifetime). Among all youths, 82.1% had used at least one type of illicit drug, and 30.1% injected drugs at least once (last six months). The prevalence of C. trachomatis infection was 6.6% (95% CI 4.1-10.0%). Prevalence did not vary significantly by sex, age or any other variable, except history of pregnancy (10.4% among youth with history of pregnancy vs 3.6% among others, P = 0.02). No cases of N. gonorrhoeae infection were found.

Quantitative comparison of radial cell columns in children with Down's syndrome and controls

No one has examined the configuration of the minicolumns in Down's syndrome (DS) brains even though these are a basic functional unit of the cortex. In the present study, the authors used computerized imaging to examine minicolumns in the posterior superior temporal gyrus in both the brains of patients with DS and normal controls. They compared the brains of children aged 4 and 6 years with those of adults for both people with DS and the normal population. Columns in the brains of two DS children aged 4 and 6 years were almost the same size as those of the adults with DS. The neuropil space in the periphery of the columns was also considerably wider. In contrast, minicolumns in aged-matched control children were smaller, both relatively and absolutely, when compared to the mean size of adult columns. The size of the minicolumns in the normal children apparently corresponded to the overall brain size, whereas the large columns in children with DS appeared to be independent of brain size, at least in area Tpt. This seems to reflect a rapid ageing process that is striking when compared to normal controls. Columns in adults with DS were large and less cell dense, while brain volumes were significantly smaller than in controls. This combination suggests reduced neuronal complexity based on a decrease in processing units, which supports previous findings of decreased cell numbers and synaptic diminution in DS brains.

Risk factors for hepatitis C virus infection among street youths

BACKGROUND

The relative contributions to risk of hepatitis C virus (HCV) infection resulting from unsafe sexual behaviours and exposures to blood (e.g., tattooing, body piercing and injection drug use) among youths at risk are not well known. We interviewed street youths about risk factors for HCV infection and documented their HCV antibody status.

METHODS

From December 1995 to September 1996 we recruited 437 youths aged 14 to 25 years who met specific criteria for itinerancy. Data on sociodemographic characteristics and lifetime risk factors were obtained during a structured interview, and a venous blood sample was taken for HCV antibody testing.

RESULTS

Many of the subjects reported behaviours that put them at risk for blood-borne diseases: 45.8% had injected drugs, 56.5% had at least 1 tattoo, and 78.3% had body piercing. The overall prevalence of HCV infection was 12.6% (95% confidence interval [CI] 9.7%-15.9%). In a multivariate logistic regression analysis, injecting drugs (adjusted odds ratio [OR] 28.4 [95% CI 6.6-121.4]), being over 18 years of age (adjusted OR 3.3 [95% CI 1.6-7.0]) and using crack cocaine (adjusted OR 2.3 [95% CI 1.0-5.3]) were independent risk factors for HCV infection. Having more than 1 tattoo (adjusted OR 1.8 [95% CI 0.95-3.6]) was marginally associated with HCV infection, and body piercing was not.

INTERPRETATION

Drug injection was the factor most strongly associated with HCV infection among street youths. Given that injection drug users are the driving force of the HCV infection epidemic in Canada, increased intervention efforts to prevent initiation of drug injection are urgently needed to curb the epidemic.

Electrochemical synthesis of antimony nanowires and analysis of diffusion layers

Synthesis of an array of antimony nanowires was performed by electrodeposition within a porous polycarbonate membrane. The sizes of pores range from 30 to 400 nm in diameter and their densities vary from 2 x 10(+6) to 2 x 10(+9) pores/cm2. To obtain optimal conditions for nanowire preparation, plating behavior was investigated by a potentiostatic method with two types (continued or pulsed) of polarization. The chronoamperometry revealed that responses depend on the type of polarization and on the pore density of the membrane. With high-density membranes, the diffusion layers of each individual pore immediately overlap when they reach the external part of the membrane. This leads to an abrupt decrease of current intensity. This phenomenon is not observed with low-density membranes because of the greater distance between pores. This mechanism, which was investigated in antimony nanowire plating, is applicable to electrodeposition of other types of materials.

New method of cardiac output measurement using ultrasound velocity dilution in rats

The aim of this study was to validate a new technique for the measurement of cardiac output (CO) based on ultrasound and dilution (COUD) in anesthetized rats. A transit time ultrasound (TTU) probe was placed around the rat carotid artery, and ultrasound velocity dilution curves were generated on intravenous injections of saline. CO by COUD were calculated from the dilution curves for normal and portal hypertensive rats in which CO was known to be increased. COUD was compared with the radiolabeled microsphere method and with direct aortic TTU flowmetry for baseline CO and drug-induced CO variations. CO in direct aortic TTU flowmetry was the ascending aorta blood flow measured directly by TTU probe (normal use of TTU flowmetry). The reproducibility of COUD within the same animal was also determined under baseline conditions. COUD detected the known CO increase in portal hypertensive rats compared with normal rats. CO values by COUD were correlated with those provided by microsphere technique or direct aortic TTU flowmetry (adjusted r = 0.76, P < 10(-4) and r = 0.79, P < 0.05, respectively). Baseline CO values and terlipressin-induced CO variations were detected by COUD and the other techniques. Intra- and interobserver agreements for COUD were excellent (intraclass r = 0.99 and 0.98, respectively). COUD was reproducible at least 10 times in 20 min. COUD is an accurate and reproducible method providing low-cost, repetitive CO measurements without open-chest surgery. It can be used in rats as an alternative to the microsphere method and to direct aortic flowmetry.

Morphological differences between minicolumns in human and nonhuman primate cortex

Our study performed a quantitative investigation of minicolumns in the planum temporale (PT) of human, chimpanzee, and rhesus monkey brains. This analysis distinguished minicolumns in the human cortex from those of the other nonhuman primates. Human cell columns are larger, contain more neuropil space, and pack more cells into the core area of the column than those of the other primates tested. Because the minicolumn is a basic anatomical and functional unit of the cortex, this strong evidence showed reorganization in this area of the human brain. The relationship between the minicolumn and cortical volume is also discussed.

Lateralization of minicolumns in human planum temporale is absent in nonhuman primate cortex

Gross analyses of large brain areas, as in MRI studies of macroanatomical structures, average subtle alterations in small regions, inadvertently missing significant anomalies. We developed a computerized imaging program to microscopically examine minicolumns and used it to study Nissl-stained slides of normal human, chimpanzee, and rhesus monkey brains in a region of the planum temporale. With this method, we measured the width of cell columns, the peripheral neuropil space, the spacing density of neurons within columns, and the Gray Level index per minicolumn. Only human brain tissue revealed robust asymmetry in two aspects of minicolumn morphology: wider columns and more neuropil space on the left side. This asymmetry was absent in chimpanzee and rhesus monkey brains.