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1.  Appearances of von Meyenburg Complex on Cross Sectional Imaging 
The von Meyenburg complex (VMC) is an uncommon congenital malformation and is characterized by benign bile duct hamartomas. These are usually discovered incidentally and may represent a diagnostic dilemma when liver metastases are suspected. MRI of VMC shows distinct imaging characteristics, but reporting of lesional contrast enhancement has been inconsistent, whilst microbubble contrast enhanced ultrasound provides ‘real-time’ evaluation of soft tissue vascularity. Given the diagnostic uncertainty over imaging in VMC, biopsy is often recommended as the definitive diagnosis. We report a biopsy proven case of VMC on a background of primary colonic malignancy investigated with ultrasound, contrast enhanced ultrasound, computed tomography CT, and magnetic resonance imaging MRI, and review the key imaging features.
PMCID: PMC3690706  PMID: 23814694
Biliary hamartoma; computed tomography; magnetic resonance imaging; ultrasound contrast; von Meyenburg
2.  Heterogeneous Vancomycin-Intermediate Susceptibility Phenotype in Bloodstream Methicillin-Resistant Staphylococcus aureus Isolates from an International Cohort of Patients with Infective Endocarditis: Prevalence, Genotype, and Clinical Significance 
The Journal of infectious diseases  2009;200(9):1355-1366.
The significance of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) is unknown. Using a multinational collection of isolates from methicillin-resistant S. aureus (MRSA) infective endocarditis (IE), we characterized IE patients with and without hVISA, and genotyped the infecting strains.
MRSA bloodstream isolates from 65 patients with definite IE from 8 countries underwent PCR for 31 virulence genes, pulsed-field gel electrophoresis, and multilocus sequence typing. hVISA was defined using population analysis profiling (PAP).
Nineteen (29.2%) of 65 MRSA IE isolates exhibited hVISA by PAP. Isolates from Oceania and Europe were more likely to exhibit hVISA than isolates from the United States (77.8% vs. 35.0% vs. 13.9%; P < .001). The prevalence of hVISA was higher among isolates with a vancomycin minimum inhibitory concentration of 2 mg/L (P = .026). hVISA-infected patients were more likely to have persistent bacteremia (68.4% vs. 37.0%; P = .029) and heart failure (47.4% vs. 19.6%; P = .033). Mortality of hVISA- and non-hVISA-infected patients did not differ (42.1% vs. 34.8%, P = .586). hVISA and non-hVISA isolates were genotypically similar.
In these analyses, hVISA occurred in over one-quarter of MRSA IE isolates, was associated with certain IE complications, and varied in frequency by geographic region.
PMCID: PMC3600359  PMID: 19811099
hVISA; Methicillin-resistant Staphylococcus aureus; endocarditis; genotype
3.  Compensatory Neural Reorganization in Tourette Syndrome 
Current Biology  2011;21(7):580-585.
Children with neurological disorders may follow unique developmental trajectories whereby they undergo compensatory neuroplastic changes in brain structure and function that help them gain control over their symptoms [1–6]. We used behavioral and brain imaging techniques to investigate this conjecture in children with Tourette syndrome (TS). Using a behavioral task that induces high levels of intermanual conflict, we show that individuals with TS exhibit enhanced control of motor output. Then, using structural (diffusion-weighted imaging) brain imaging techniques, we demonstrate widespread differences in the white matter (WM) microstructure of the TS brain that include alterations in the corpus callosum and forceps minor (FM) WM that significantly predict tic severity in TS. Most importantly, we show that task performance for the TS group (but not for controls) is strongly predicted by the WM microstructure of the FM pathways that lead to the prefrontal cortex and by the functional magnetic resonance imaging blood oxygen level-dependent response in prefrontal areas connected by these tracts. These results provide evidence for compensatory brain reorganization that may underlie the increased self-regulation mechanisms that have been hypothesized to bring about the control of tics during adolescence.
► We combine behavioral studies with structural and functional neuroimaging ► We report enhanced cognitive control in children with Tourette syndrome ► Frontal lobe white-matter microstructure predicts tic severity in Tourette syndrome ► Frontal lobe white-matter and fMRI BOLD predict cognitive control in Tourette syndrome
PMCID: PMC3076629  PMID: 21439830
4.  Family Structure History: Links to Relationship Formation Behaviors in Young Adulthood 
Using data from three waves of the National Longitudinal Study of Adolescent Health (N=4,538), we examine the intergenerational link between parental family structure history and relationship formation in young adulthood. We investigate: (a) first, whether parental family structure history is associated with young adults' own relationship formation behaviors; (b) second, which dimensions of family structure history are most predictive of children's later relationship formation behaviors; and (c) third, if the association between family structure history and young adulthood relationship formation differs by gender. Our findings provide evidence of an intergenerational link between parent relationship histories and their offspring's own relationship formation behaviors in young adulthood, over and above confounding factors.
PMCID: PMC2947371  PMID: 20890404
Family structure; intergenerational transmission; living arrangements; National Longitudinal Study of Adolescent Health (Add Health); youth/emergent adulthood
5.  High-Risk Subsequent Births Among Co-Residential Couples: The Role of Fathers, Mothers, and Couples 
Fathering  2009;7(1):91-102.
This study examines predictors of a cumulative measure of high-risk births, rather than single risks separately, as in prior research. Using the Early Childhood Longitudinal Study-Birth Cohort survey, we incorporate data from fathers and mothers to assess characteristics associated with births subsequent to a focal child’s birth within high-risk circumstances. Components of a high-risk birth include: high-parity, very closely-spaced, or births to unmarried couples, unhappy couples, or couples in high-conflict relationships. Both fathers’ and mothers’ pregnancy intentions affect whether couples have a subsequent high-risk birth. The odds of a high-risk subsequent birth, relative to no birth and to a low-risk birth, are more than twice as high if only the father intended the birth of the previous child rather than if the child was intended by both the mother and father. High-risk subsequent births are much more likely among couples where the prior child was high risk and where family income was low, and lower where both father and mother had lived with both biological parents. Findings highlight the importance of father data in fertility research.
PMCID: PMC2850542  PMID: 20379382
fertility; pregnancy intentions; relationship quality; nonmarital childbearing
6.  Phylogenetic Analysis of Viridans Group Streptococci Causing Endocarditis ▿  
Journal of Clinical Microbiology  2008;46(9):3087-3090.
Identification of viridans group streptococci (VGS) to the species level is difficult because VGS exchange genetic material. We performed multilocus DNA target sequencing to assess phylogenetic concordance of VGS for a well-defined clinical syndrome. The hierarchy of sequence data was often discordant, underscoring the importance of establishing biological relevance for finer phylogenetic distinctions.
PMCID: PMC2546745  PMID: 18650347
7.  Genotypic Diversity of Coagulase-Negative Staphylococci Causing Endocarditis: a Global Perspective▿  
Journal of Clinical Microbiology  2008;46(5):1780-1784.
Coagulase-negative staphylococci (CNS) are important causes of infective endocarditis (IE), but their microbiological profiles are poorly described. We performed DNA target sequencing and susceptibility testing for 91 patients with definite CNS IE who were identified from the International Collaboration on Endocarditis—Microbiology, a large, multicenter, multinational consortium. A hierarchy of gene sequences demonstrated great genetic diversity within CNS from patients with definite endocarditis that represented diverse geographic regions. In particular, rpoB sequence data demonstrated unique genetic signatures with the potential to serve as an important tool for global surveillance.
PMCID: PMC2395089  PMID: 18367572
8.  Contraceptive Use and Consistency in U.S. Teenagers’ Most Recent Sexual Relationships 
Most U.S. teenage pregnancies are unintended, partly because of inconsistent or no use of contraceptives. Understanding the factors associated with contraceptive use in teenagers’ most recent relationships can help identify strategies to prevent unintended pregnancy.
Data on 1,468 participants in Waves 1 and 2 of the National Longitudinal Study of Adolescent Health who had had two or more sexual relationships were analyzed to assess factors associated with contraceptive use patterns in teenagers’ most recent sexual relationship. Odds ratios were generated through logistic regression.
Many relationship and partner characteristics were significant for females but nonsignificant for males. For example, females’ odds of ever, rather than never, having used contraception in their most recent relationship increased with the duration of the relationship (odds ratio, 1.1); their odds were reduced if they had not known their partner before dating him (0.2). The odds of consistent use (vs. inconsistent or no use) were higher for females in a “liked” relationship than for those in a romantic relationship (2.6), and for females using a hormonal method instead of condoms (4.5). Females’ odds of consistent use decreased if the relationship involved physical violence (0.5). Among teenagers in romantic or “liked” relationships, the odds of ever-use and of consistent use were elevated among females who had discussed contraception with the partner before their first sex together (2.9 and 2.1, respectively), and the odds increased among males as the number of presexual couple-like activities increased (1.2 for each).
Teenagers must use contraception consistently over time and across relationships despite pressure not to. Therefore, they must learn to negotiate sexual and contraceptive decisions in each relationship.
PMCID: PMC1473989  PMID: 15687085
9.  Patterns of Contraceptive Use Within Teenagers’ First Sexual Relationships 
Teenagers have a high unintended pregnancy rate, in part because of inconsistent use or nonuse of contraceptives. It is important to determine how partner and relationship characteristics are related to contraceptive use and consistency within adolescents’ first sexual relationships.
Logistic and multinomial logistic regression analyses of data from 1,027 participants in the first two waves of the National Longitudinal Study of Adolescent Health examined the influence of relationship and partner characteristics on ever-use and consistent use of contraceptive methods during teenagers’ first sexual relationships.
Teenagers who had waited a longer time between the start of a relationship and first sex with that partner, discussed contraception before first having sex or used dual contraceptive methods had significantly increased odds of ever or always using contraceptives. Adolescents who had taken a virginity pledge, had an older partner, had a greater number of close friends who knew their first partner, or reported having a relationship that was not romantic but that involved holding hands, kissing and telling their partners they liked or loved them had decreased odds of contraceptive use or consistency. As relationship length increased, teenagers were more likely to ever have used a method, but less likely to always have used a method.
Parents and programs should encourage teenagers to delay sexual intercourse, discuss contraception with partners before initiating sex and be vigilant about contraceptive use, particularly in long-term sexual relationships and in relationships with older partners.
PMCID: PMC1473988  PMID: 14744656

Results 1-9 (9)