Nosocomial outbreak of Achromobacter spp. bacteremia due to germicide contamination: a systematic review

OBJECTIVE

Achromobacter spp. are aerobic, non-fermentative Gram-negative bacilli that can be widely found in aquatic environments. Nosocomial outbreaks and pseudo-outbreaks of Achromobacter spp. bacteremia have been recognized for decades. Notably, commonly used germicides in hospital settings constitute important sources for these outbreaks. This review aims at summarizing the latest studies and presents the characteristics of nosocomial outbreaks of Achromobacter spp. bacteremia caused by germicide contamination.

MATERIALS AND METHODS

A systematic search of the PubMed and EMBASE databases was conducted for articles published in English between January 1, 2000, and June 10, 2022.

RESULTS

Overall, 170 articles were retrieved, and 7 studies were finally included in the systematic review. Whether true or pseudo-bacteremia, positive blood culture results were most commonly reported in immunosuppressed patients or those with indwelling catheters. The most commonly reported contaminated germicide was chlorhexidine solution used as both an antiseptic and disinfectant. Atomizers, dispensers, and various product containers were identified as reservoirs. The prognoses of the affected patients were generally favorable.

CONCLUSIONS

Awareness about the high survival ability of Achromobacter spp. in germicides and the possible hospital reservoirs of these microbes will help to improve infection control and prevent nosocomial outbreaks or pseudo-outbreaks caused by Achromobacter spp.

Fluctuation of BCR-ABL1 qPCRIS level beyond 0.1%IS after stopping tyrosine kinase inhibitor in chronic myeloid leukaemia patients with deep molecular response for at least two years

Fluctuation of BCR-ABL1 real-time quantitative polymerase chain reaction in International Scale (qPCR^IS) level below major molecular response (MMR) (0.1%^IS) is a known phenomenon after stopping tyrosine kinase inhibitor (TKI) in chronic myeloid leukaemia (CML) patients who are attempting treatment free remission (TFR). We report here four cases of fluctuation beyond MMR during conduct of a Malaysia Stop TKI Trial (MSIT) to examine the validity of the commonly used relapse criterion - loss of MMR for one reading - aiming to provide evidence in setting relapse criteria for future CML patients who want to attempt TFR.

Letter to the Editor: Effects of the COVID-19 Pandemic on COVID-19 Negative Geriatric Patients with Hip Fractures

Since December 2019, the novel coronavirus (COVID-19) had affected millions globally, particularly putting elderly and persons with chronic diseases at risk (1). 95% of all COVID-19 deaths in Singapore are older adults (2). As public health policymakers try to control the pandemic by focusing resources on COVID-19, the general population fear contracting coronavirus from hospitals, resulting in changes in their healthcare seeking behaviour. We describe two cases demonstrating the direct and indirect impact of COVID-19 to our geriatric patients in Singapore who have sustained hip fractures.

Knowledge, attitudes and behaviour towards needlestick injuries among junior doctors

BACKGROUND

Needlestick injuries (NSIs) are common healthcare-related injuries and possible consequences include blood-borne infections. Despite that, a large proportion of NSIs are not reported.

AIMS

To estimate the prevalence of under-reporting of NSIs and to evaluate the knowledge, attitude and behaviour towards NSIs among junior doctors in a tertiary hospital in Singapore.

METHODS

An explanatory sequential mixed-methods design was employed. Quantitative data were collected through questionnaires completed by 99 junior doctors. Descriptive statistics and bivariate analysis were performed to evaluate socio-demographic characteristics, NSI history and NSI reporting practices. Qualitative data were collected through 12 in-depth interviews. Participants were purposively recruited, and semi-structured topic guides were developed. Data were analysed using a thematic approach.

RESULTS

Fifty-two per cent of respondents had history of NSI. Of those with history of NSI, 31% did not report injury. NSI reporters were 1.52 times as likely to be aware of how to report injury (P < 0.05), and 1.63 times as likely to feel that reporting benefits their health (P < 0.01) compared with non-reporters. NSI reporters were 83% more likely to report a clean NSI (P = 0.05). For non-reporters, the main reasons for not reporting were perceived low risk of transmission (41%) and lack of time to report (35%). Themes identified in the qualitative data include perceived benefits, perceived barriers, perceived threats, cues to action and organizational culture.

CONCLUSION

Under-reporting of NSIs may have significant implications for patients and healthcare workers. Addressing identified factors and instituting targeted interventions will help to improve reporting rates.

Astrocytic water channel aquaporin-4 modulates brain plasticity in both mice and humans: a potential gliogenetic mechanism underlying language-associated learning

The role of astrocytes in brain plasticity has not been extensively studied compared with that of neurons. Here we adopted integrative translational and reverse-translational approaches to explore the role of an astrocyte-specific major water channel in the brain, aquaporin-4 (AQP4), in brain plasticity and learning. We initially identified the most prevalent genetic variant of AQP4 (single nucleotide polymorphism of rs162008 with C or T variation, which has a minor allele frequency of 0.21) from a human database (n=60 706) and examined its functionality in modulating the expression level of AQP4 in an in vitro luciferase reporter assay. In the following experiments, AQP4 knock-down in mice not only impaired hippocampal volumetric plasticity after exposure to enriched environment but also caused loss of long-term potentiation after theta-burst stimulation. In humans, there was a cross-sectional association of rs162008 with gray matter (GM) volume variation in cortices, including the vicinity of the Perisylvian heteromodal language area (Sample 1, n=650). GM volume variation in these brain regions was positively associated with the semantic verbal fluency. In a prospective follow-up study (Sample 2, n=45), the effects of an intensive 5-week foreign language (English) learning experience on regional GM volume increase were modulated by this AQP4 variant, which was also associated with verbal learning capacity change. We then delineated in mice mechanisms that included AQP4-dependent transient astrocytic volume changes and astrocytic structural elaboration. We believe our study provides the first integrative evidence for a gliogenetic basis that involves AQP4, underlying language-associated brain plasticity.

Abstract P2-05-07: Whole exome sequencing of extreme responders reveals low mutation burden in metastatic breast cancer

Background: Extreme responders to anticancer therapy are rarely encountered in the treatment of advanced breast cancer patients, but their treatment response have not been investigated on the whole exome level. We performed whole exome analysis to characterize genomic landscape of extreme responders in metastatic breast cancer patients.

Methods: Clinical samples were obtained from patients who showed exceptional response to anti-HER2 therapy or hormonal therapy. Non-responders were selected among those who did not respond. Matched breast tumor tissue (somatic DNA) and blood samples (germline DNA) were collected from a total of 18 responders (12 ER+, 6 HER2+) and 8 non-responders (6 ER+, 1 HER2+, 1 TNBC). Whole exome sequencing using Illumina HiSeq2500 was performed on the 26 patients (52 samples). Somatic single nucleotide variants (SNVs), indels and copy number variants (CNVs) were identified for each patient genome. Group specific somatic variants and mutation burden were statistically analyzed.

Findings: Cancer exomes were characterized by 1,455 somatic single-nucleotide variants (1,327 missense, 80 nonsense, 36 splice-site, 12 start/stop-lost), 149 insertions/deletions (108 frameshift, 41 inframe), with a median of 1 mutations per Mb (0.2 to 2.7 mutations per Mb) in all patients. Responders harbored a significantly lower non-synonymous mutation burden than non-responders (median, 27 vs. 90.5, P=0.01), and copy number variation burden was also lower (median 23 vs. 31, P=0.14). Multivariate analyses of factors influencing progression-free survival showed that high mutation burden and visceral metastases were significantly related with progression.

Interpretation: Extreme responders of metastatic breast cancer are characterized by low nonsynonymous mutational burden.

Citation Format: Sohn J, Lim SM, Kim E, Kim S, Koo JS, Kim SI, Park S, Park HS, Kwon N-J, Kim GM, Kim S. Whole exome sequencing of extreme responders reveals low mutation burden in metastatic breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-05-07.

Abstract OT2-01-03: A prospective randomized study comparing surgery using electrosurgical bipolar sealing devices and surgery using conventional electro-cautery

Background: Seroma and lymphorrhea are the most common complication following mastectomy and/or axillary lymph node dissection (ALND). The manifestation of seroma accelerates complications such as post-operative bleeding, wound infection, prolonged recovery period. Sealing blood vessels and lymph drainages adequately during mastectomy and/or ALND may play a main role in reducing complication. Therefore, adequate sealing vessels and lymphatics during the surgery is important to reduce seroma and lymphorrhea related complications in patients with breast cancer. Objective: This study aims to show that electrosurgical bipolar sealing device for mastectomy could provide clinical benefit in reducing seroma formation. Design: ELBCE (ELectrosurgical Bipolar Devices VS Convention Electronicautery, NCT03166384)is a prospective, randomized, two-arm assignment controlled trial of application of electrosurgical bipolar sealing device for mastectomy in patients with breast cancer. Patients is randomized in 1:1 ratio to conventional suture and tie group or electrosurgical bipolar sealing devices group. Randomization is performed using opening sealed envelope before enrollment. The primary end point is to compare the total drainage volume until drain tube removal. The time to drain removal is also measured. The secondary end points is the total amount of aspiration from seroma after drain tube removal, and the frequency of seroma aspiration. Statistical consideration: A sample size 44 subjects per each arm was planned to provide a 90% power to detect a 25% decrease of the total amount of drainage fluid after surgery by using an electrosurgical bipolar sealing device when compared to a conventional suture and tie technique. In our experience, the average total volume of fluid after conventional suture and tie technique is 220 mL, with a standard deviation of 80. Eligibility criteria:Inclusion criteria are patients older than 20 years and those who planned to undergo total mastectomy and/or ALND. Exclusion criteria are bilateral breast cancer patients, male patients, patients who underwent ipsilateral axillar surgery or radiation therapy, recurrent breast cancer patients, patients without drain catheter, and patients with ductal carcinoma in situ who have not undergone ipsilateral sentinel lymph node biopsy or ALND.Present accrual and target accrual:ELSEBA study has an accrual target of 88 patients. To date, 8 patients have been randomized. Contact information:Dr. Hyung Seek Park, E-mail: hyungseokpark.md@gmail.com; imgenius@yuhs.ac, Telephone: +82-2-2228-2100

Citation Format: Yoon KH, Park HS, Kim JH, Kim JY, Lim SM, Kim SI, Cho YU. A prospective randomized study comparing surgery using electrosurgical bipolar sealing devices and surgery using conventional electro-cautery [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT2-01-03.

Abstract P6-11-13: Not presented

This abstract was not presented at the symposium.

Light chain multiple myeloma: an evaluation of its biochemical investigations

Multiple myeloma is a type of plasma cell dyscrasia, characterised by presence of paraprotein or monoclonal (M)-protein in serum or urine. The M-protein may consist of an intact immunoglobulin, the heavy chain only or the light chain only. The latter, designated as light chain multiple myeloma (LCMM) makes up almost 20% of myelomas. Clinical manifestation is often heralded by hypercalcaemia, renal impairment, normocytic normochromic anaemia and bone lesions, reflecting end-organ damage, collectively known as the acronym CRAB. In particular, free light chain nephrotoxicity accounts for the high prevalence of renal impairment seen in LCMM. This case illustrates a typical presentation of LCMM with focal discussion on its initial and diagnostic, as well as prognostic biochemical investigations.

Posterior Elbow Dislocation with Brachial Artery Thrombosis Treated Non-surgically: A Case Report

The brachial artery is rarely injured in closed posterior dislocation of the elbow, unlike the high rate of vascular injury seen after dislocation of the knee. Despite the anatomical proximity of the brachial artery to the elbow joint, most cases of brachial artery injury after dislocation of the elbow are related to an associated fracture, an open injury or high-energy trauma. A high index of suspicion should be maintained as well as a thorough neurovascular examination with regards this potentially disastrous complication. We describe an unusual case of complete thrombosis of the brachial artery presenting with a posterior elbow dislocation following a fall (low energy trauma) that was treated nonoperatively. At three months follow-up, patient had good circulation over the affected limb, no complaints of ischemic pain or cold intolerance, no signs of Volkmann’s ischemic contracture, and a range of motion that was comparable to the contralateral limb.

Determination of the 99th percentile upper reference limit for high-sensitivity cardiac troponin I in Malaysian population

Introduction of high-sensitivity cardiac troponin I (hscTn I) assays for routine clinical use in Malaysia requires determination of the 99^th percentile upper reference limit (URL) for each assay to suit local context. Hence, this study aimed to determine the 99^th percentile URL for hscTn I in the Malaysian population. A total of 250 (120 males and 130 females) healthy Malaysian blood donors aged 18 to 60 years old were recruited. Blood samples for hscTn I were measured using Abbott Diagnostics hscTn I assay on Architect i2000sr analyser. The 99^th percentile was calculated using a non-parametric method and gender specific results were compared. The 99^th percentile URL for hscTn I for the overall population was 23.7 ng/L, with gender specific values being 29.9 ng/L and 18.6 ng/L for male and female, respectively. Females had significantly lower hscTn I compared to males. This study confirms the use of gender specific 99^th percentile URL for hscTn I for clinical use in a multi-ethnic Malaysian population.

Serologic evidence of West Nile virus and Usutu virus infections in Eurasian coots in the Netherlands

West Nile virus (WNV) and Usutu virus (USUV) are arboviruses that are maintained in enzootic transmission cycles between mosquitoes and birds and are occasionally transmitted to mammals. As arboviruses are currently expanding their geographic range and emerging in often unpredictable locations, surveillance is considered an important element of preparedness. To determine whether sera collected from resident and migratory birds in the Netherlands as part of avian influenza surveillance would also represent an effective source for proactive arbovirus surveillance, a random selection of such sera was screened for WNV antibodies using a commercial ELISA. In addition, sera of jackdaws and carrion crows captured for previous experimental infection studies were added to the selection. Of the 265 screened serum samples, 27 were found to be WNV-antibody-positive, and subsequent cross-neutralization experiments using WNV and USUV confirmed that five serum samples were positive for only WNV-neutralizing antibodies and seven for only USUV. The positive birds consisted of four Eurasian coots (Fulica atra) and one carrion crow (Corvus corone) for WNV, of which the latter may suggest local presence of the virus, and only Eurasian coots for USUV. As a result, the screening of a small selection of serum samples originally collected for avian influenza surveillance demonstrated a seroprevalence of 1.6% for WNV and 2.8% for USUV, suggesting that this sustained infrastructure could serve as a useful source for future surveillance of arboviruses such as WNV and USUV in the Netherlands.

Lactobacillus fermentum IM12 attenuates inflammation in mice by inhibiting NF-κB-STAT3 signalling pathway

In the present study, we isolated Lactobacillus fermentum IM12 from human gut microbiota, which strongly inhibited interleukin (IL)-6 expression and STAT3 activation in lipopolysaccharide (LPS)-stimulated murine peritoneal macrophages, and examined its anti-inflammatory effect in mice with carrageenan-induced hind-paw oedema (CIE) or 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis (TIC). Oral administration of IM12 (0.2×109, 1×109 or 5×109 cfu/mouse, once a day for 3 days) in mice with CIE significantly suppressed the increase of oedema volume and thickness, as well as myeloperoxidase activity and IL-6, IL-17, NO, and prostaglandin E2 levels in the carrageenan-stimulated paw. Treatment with IM12 (1×109 cfu/mouse, once a day for 3 days) in mice with TIC significantly suppressed colon shortening, and myeloperoxidase activity and IL-6 and IL-17 levels. Treatment with IM12 in mice with CIE or TIC also suppressed the expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2, as well as activation of nuclear factor kappa beta (NF-κB) and signal transducer and activator of transcription 3 (STAT3). Furthermore, IM12 significantly inhibited the expression of iNOS, and COX-2, as well as activation of NF-κB in LPS-stimulated mouse peritoneal macrophages. The inflammatory effect of heat-inactivated IM12 was significantly different to that of live IM12 in mice with TIC, although anti-inflammatory effect of IM12 was reduced by heat treatment. Based on these findings, IM12 may attenuate inflammation by inhibiting NF-κB-STAT3 signalling pathway.

Abstract P5-16-25: Serum 25-hydroxyvitamin D levels and oncologic outcomes of breast cancer patients receiving neoadjuvant chemotherapy

Background:According to prior studies, the role of serum vitamin D3 has been inconsistentand clinical implications of 25-hyrdoxyvitamin D (25-OHD) have been little studiedin breast cancer patients receiving neoadjuvant chemotherapy (NCT).

Objectives: The aims of study were to investigate changes in 25-OHD levels before and after NCT and to determine the association of 25-OHD and oncologic outcomes including pathological complete response (pCR) in breast cancer patients.

Patients and Materials: From January 2010 to December 2013, serum 25-OHD levels at pre- and post-NCT were measured in 377 breast cancer patients. The association of serum 25-OHD levels with clinicopathological data including breast cancer subtypes, pCR and survival were retrospectively analysed. Delta 25-OHD was calculated as serum 25-OHDlevels before minus after NCT.

Results: Mean ageof study population was 48.7 yearsand mean follow-up periods were 35.9months.Mean baseline serum 25-OHD concentration was 14.60 ng/mL (standard deviation, 7.44) and more than 80% of patients showed insufficient 25-OHD levels. The mean 25-OHDat post-NCT was 12.16 ng/mL (standard deviation, 6.87).There was a significant decrease in serum 25-OHD after NACT (p&lt;0.001).The pCR rates were 25.7% among study cohort.However, 25-OHD levels at baseline and post-NCT were not related to pCR and survival outcomes. No associations were found between pCR and delta 25-OHD. According to stratification by breast cancer subtypes, however, patients with ≥ -2.67 (median value) of delta 25-OHD revealed a trend of higher achievement of pCR and better survival in luminal A subtype. No associations were found among the other subtypes.

Conclusions: Many Korean breast cancer patients showed insufficient serum 25-OHD levels at diagnosis of malignancy and a significant decrease in serum vitamin D3 after NACT was observed.No significant association of 25-OHD 3 with pCR and survival was found. Therefore, correction or maintenance of appropriate serum 25-OHD levels should be focused for bone health as comprehensive management of breast cancer during NCT.In addition, possible oncological aspects of 25-OHD should further researched individually considering breast subtypes.

Citation Format: Park S, Lee JS, Kim JH, Lim SM, Park HS, Kim SI. Serum 25-hydroxyvitamin D levels and oncologic outcomes of breast cancer patients receiving neoadjuvant chemotherapy [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 P5-16-25.

Abstract OT2-04-01: Study on the usefulness of the skin wound therapeutic agent 'Neo dermal activator' in breast cancer surgery

Background : Wound infection after breast cancer surgery is considered to be factors that increase the discomfort of the patient and increase of the extension and the use of antibiotics in the treatment time period, in particular breast cancer postoperative wound infection resulting slow the implementation of adjunctive therapy such as radiation therapy or chemotherapy after surgery can cause, it is important to effectively prevent, there has been a development of a variety of skin wound therapeutic agent to reduce them. The purpose of this study was to evaluate the effects of the wound dressing with existing wound dressing Neo dermal activator compared to the patients receiving preoperative chemotherapy.

Methods : A total of 54 breast cancer patients who recieved BCS & mastectomy devided two group(each 27 patients) through the random assignment between Jan, 2016 and June, 2016. Day one weeks after surgery to examine the wound infection rate (surgical site infection, SSI rate). After six months of outpatient surgery visits to check the wounds of patients, using the VAS records the scar of the wound satisfaction. For patients who underwent radiation therapy, check out the time it took to begin radiation therapy after surgery.

All tests were two-sided. All statistical analyses were performed using SPSS version 20.0 (SPSS Inc., Chicago, Illinois, USA).

Eligbility criteria is :

- one side breast cancer

- not inflammatory breast cancer

- recieved BCS and mastectomy only (without immediate reconstruction surgery)

- stage IV breast cancer.

Citation Format: Kim JH, Lim SM, Kim SI, Park SH, Park HS, Kim JY. Study on the usefulness of the skin wound therapeutic agent 'Neo dermal activator' in breast cancer surgery [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 OT2-04-01.

Pediococcus acidilactici LAB4 and Lactobacillus plantarum LAB12 assimilate cholesterol and modulate ABCA1, CD36, NPC1L1 and SCARB1 in vitro

There is growing interest in the use of probiotic lactic acid bacteria (LAB) for prevention of hypercholesterolaemia. This study assessed the cholesterol lowering ability of Pediococcus acidilactici LAB4 and Lactobacillus plantarum LAB12 in growth media. Both LAB yielded >98% (39.2 μg/ml) cholesterol lowering in growth media. Nile Red staining indicated direct assimilation of cholesterol by the LAB. The LAB were then explored for their prophylactic (pre-treatment of HT29 cells with LAB prior to cholesterol exposure) and biotherapeutic (treatment of HT29 cells with LAB after exposure to cholesterol) use against short and prolonged exposure of HT29 cells to cholesterol, respectively. For HT29 cells pre-treated with LAB, cholesterol lowering was accompanied by down-regulation of ATP-binding cassette family transporter-type A1 (ABCA1), cluster of differentiation 36 (CD36) and scavenger receptor class B member 1 (SCARB1). HT29 cells treated with LAB after prolonged exposure to cholesterol source, on the other hand, was associated with up-regulation of ABCA1, restoration of CD36 to basal level and down-regulation of Neimann-Pick C1-Like 1 (NPC1L1). The present findings implied the potential use of LAB4 and LAB12 as part of the strategies in prevention and management of hypercholesterolaemia.

Comparison of cytotoxicity test models for evaluating resin-based composites

OBJECTIVES

This study compared different cytotoxicity test models for evaluating resin-based composites (RBCs) and assessed the biocompatibility of standard and bulk-fill RBCs.

METHODS

A standard (spectrum TPH) and a bulk-fill (smart dentin replacement (SDR)) RBC were selected. Disc-shaped specimens (7 mm diameter) of 2 and 4 mm thickness were polymerized for 20 s with a LED curing light of 700 mW/cm² irradiance. The specimens ( n = 5) were subjected to micro-hardness testing and three cytotoxicity test models (direct contact, indirect contact and extract tests) with the established L-929 cell line. Hardness ratios of top and bottom surfaces of specimens were computed to assess the effectiveness of cure. For the direct and indirect contact tests, the cells were stained and zones of inhibition were analyzed after material contact for 24 h. For the extract test, cells were exposed to extracts for 24 h, and cell viability was measured. Data was analyzed using analysis of variance/Scheffe's post hoc test and Pearson's correlation ( p < 0.05).

RESULTS

The lowest mean hardness ratio and highest cytotoxicity were observed for TPH at 4 mm. At 4-mm thickness, SDR was found to be biocompatible with all three models. Correlations between hardness ratio and cell viability ranged from r = 0.89-0.96 for the various tests. A significant correlation ( r = 0.97) was also observed between the three test models.

CONCLUSION

Our data indicated consistency between direct contact, indirect contact and extract test models for cytotoxicity testing of RBCs. Bulk placement and curing at 4 mm for the bulk-fill RBC evaluated did not result in undue cytotoxicity.

Predisposition to and effects of methamphetamine use on the adolescent brain

Adolescence is a period of heightened vulnerability both to addictive behaviors and drug-induced brain damage. Yet, only limited information exists on the brain mechanisms underlying these adolescent-specific characteristics. Moreover, distinctions in brain correlates between predisposition to drug use and effects of drugs in adolescents are unclear. Using cortical thickness and diffusion tensor image analyses, we found greater and more widespread gray and white matter alterations, particularly affecting the frontostriatal system, in adolescent methamphetamine (MA) users compared with adult users. Among adolescent-specific gray matter alterations related to MA use, smaller cortical thickness in the orbitofrontal cortex was associated with family history of drug use. Our findings highlight that the adolescent brain, which undergoes active myelination and maturation, is more vulnerable to MA-related alterations than the adult brain. Furthermore, MA-use-related executive dysfunction was greater in adolescent MA users than in adult users. These findings may provide explanation for the severe behavioral complications and relapses that are common in adolescent-onset drug addiction. Additionally, these results may provide insights into distinguishing the neural mechanisms that underlie the predisposition to drug addiction from effects of drugs in adolescents.