Abstract 1257: Ursolic acid modulates T Cell compartment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer with inflammation-associated. The cellular immune landscape of HCC can elucidate the tumor response and suggest the best strategy for effective T-cell responses. Ursolic acid (UA) is a pentacyclic triterpenoid with anti-inflammatory properties and can suppress tumor cells by oncogenic growth signaling and has known anti-inflammatory properties. To comprehend the effect of UA on the HCC immune landscape, we evaluated lymphoid cells in a syngeneic tumor model of an immunocompetent rat. The mcA-RH7777 rat cell line was implanted in Buffalo rats. The tumor size was verified with ultrasound, and rats received UA 75 mg/Kg or extra-virgin olive oil(EVOO), UA vehicle, by oral gavage every other day for 7 and 14 days. Tumor cells were isolated and stained with CD45, CD3, CD4, CD8, CD25, CD103, CD161, IL-17A, INFg, CD279/PD-1, FOXP3 antibodies. Immunophenotyping by spectral cytometry was analyzed in Flow Jo Software. The partial results from 7 and 14 days demonstrated UA had the same effect as EVOO. Tumor-infiltrated lymphocytes (TIL) were increased in EVOO and UA in 7 and 14 days of treatment in comparison with untreated tumors. For 7 days group, NK-like cells were higher in UA and EVOO than untreated (p=0.004 and p=0.004), while for 14 days there is a tendency to decrease it in oil and UA treatment. CD3+CD8+ (Tc) and CD3+CD4+(Th) populations seem reduced after oil and UA treatment. Also, both populations had low expression of INFg+ in all treatments and times used. EVOO may increase the population of CD25+FOXP3+(TREG) PD-1+ cells after 14 days of oil-only treatment. CD25+FOXP3+(TREG) INFg+ after very low representation in 7 days, seems to recover to normal level after 14 days in the UA group. UA group had tumors presenting more CD3+ (p=0.0004), CD3+CD4+ (Th), and CD3+/CD8+ (Tc) after 14 days (p=0.004 and p=0.0015 respectively). Evaluating the control rat liver (without tumor), we could see increased Th (p=0.02) and decreased Th17 cells (p=0.0002) in comparison with the liver surrounding the tumor untreated. The effect of UA was similar in the spleen. Tc (p=0.0015) and Th (p=0.0004) had a bigger population in the control and no activation of Tc and Th (INFg+) compared with the spleen of untreated tumor rats. UA in the liver and spleen, the decrease in the Th17, but not in the tumor. Maybe because tumors hadn't a consistent amount of Th17. EVOO seems to contribute to the infiltration of T cells, but not to activation of these cells. Oral gavage and olive oil may interpose the UA effect. The preliminary result using trans arterial embolization may be more effective as a combined strategy against HCC.

Citation Format: Patricia L. Da Costa Lopez, Andrea C. Cortes, Kyiouki Minamiguchi, Malea L. Williams, Crystal J. Dupuis, Simone Anfossi, Marites P. Melancon, Rony Avritscher. Ursolic acid modulates T Cell compartment of hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1257.

Bismuth Nanoparticle and Polyhydroxybutyrate Coatings Enhance the Radiopacity of Absorbable Inferior Vena Cava Filters for Fluoroscopy-Guided Placement and Longitudinal Computed Tomography Monitoring in Pigs

Inferior vena cava filters (IVCFs) constructed with poly-p-dioxanone (PPDO) are promising alternatives to metallic filters and their associated risks and complications. Incorporating high-Z nanoparticles (NPs) improves PPDO IVCFs' radiopacity without adversely affecting their safety or performance. However, increased radiopacity from these studies are insufficient for filter visualization during fluoroscopy-guided PPDO IVCF deployment. This study focuses on the use of bismuth nanoparticles (BiNPs) as radiopacifiers to render sufficient signal intensity for the fluoroscopy-guided deployment and long-term CT monitoring of PPDO IVCFs. The use of polyhydroxybutyate (PHB) as an additional layer to increase the surface adsorption of NPs resulted in a 2-fold increase in BiNP coating (BiNP-PPDO IVCFs, 3.8%; BiNP-PPDO + PHB IVCFs, 6.2%), enabling complete filter visualization during fluoroscopy-guided IVCF deployment and, 1 week later, clot deployment. The biocompatibility, clot-trapping efficacy, and mechanical strength of the control PPDO (load-at-break, 6.23 ± 0.13 kg), BiNP-PPDO (6.10 ± 0.09 kg), and BiNP-PPDO + PHB (6.15 ± 0.13 kg) IVCFs did not differ significantly over a 12-week monitoring period in pigs. These results indicate that BiNP-PPDO + PHB can increase the radiodensity of a novel absorbable IVCF without compromising device strength. Visualizing the device under conventional radiographic imaging is key to allow safe and effective clinical translation of the device.

Abstract 6136: Generation and characterization of colorectal cancer cell lines from the Buffalo rat

Introduction: Rat models of metastatic colorectal cancer (mCRC) to the liver are ideal for the development of transarterial therapies. To date, only one model of CRC cells grown in vitro and implanted into the liver of syngeneic rats is available. Yet, the small size of the WAG-Rij rat limits the use of the CC-531/WAG-Rij model for transarterial interventions. This work was aimed at generating an analogous model on the Buffalo rat, strain that has successfully been used for transarterial interventions in primary liver cancer.

Materials and Methods: To induce CRC, 5 6-week old Buffalo rats were treated with Azoxymethane (AOM) and Dextran Sodium Sulfate (DSS). To assess tumor progression, the rats were regularly examined by colonoscopy as well as to T1- and T2-MR imaging from w20 up to w63. Standard procedures of tumor cell isolation and in vitro expansion were used. Once the polyclonal lines were established, expression of E-cadherin, Ceacam5, Mucin1, Vimentin1, and S100a4 was evaluated by flow cytometry (FACS) or qPCR. Additionally, the gene regions of APC (nt. 3049 to 3697) and β-catenin (nt. 371 to 1104) were analyzed by Sanger sequencing. Lastly, 23 adult Buffalo rats received implantations of 0.4-1 × 107 cells in the liver only or in the liver as well as subcutaneously.

Results: Colonoscopies, MRIs, and histopathology demonstrated that all 5 rats treated with AOM/DSS developed colorectal neoplasms by w22. Tumors were harvested at various time points, at weeks 24, 32, 45, and 63. 2 polyclonal cell lines derived from invasive adenocarcinomas of a female (18L002) and a male (18L004) were successfully established and have proliferated in vitro >1year. FACS and qPCR results showed that both lines express the epithelial markers E-cadherin, Ceacam5, and Mucin1. Interestingly, despite high E-cadherin expression in both lines (>90% by FACS), qPCR data revealed that both lines also express the mesenchymal markers Vimentin and S100a4, suggestive of a trans-differentiated phenotype. DNA sequences of regions of the APC and β-catenin genes frequently mutated by AOM treatment appeared to be intact in both lines. MRIs of the 23 rats that received implants showed that 4 seem to have allowed for short-term growth (~14d) of the 18L004 cells in the liver before being re-absorbed. Histopathological analyses showed evidence of a serosal reaction at the site of implantation in those cases.

Conclusions: Two polyclonal CRC lines with phenotypical characteristics of trans-differentiated cells were successfully generated from AOM/DSS-treated Buffalo rats. In spite of continued in vitro growth for over a year, neither line was tumorigenic in vivo, potentially due to the lack of mutations in key regions of the APC and β-catenin genes. Forced expression of mutant genes known to drive CRC progression such as β-catenin, Kras, or P53 could potentially increase in vivo tumorigenicity and allow for the establishment of a rat model of mCRC suitable for the study of transarterial therapies.

Citation Format: Nina M. Muñoz, Crystal J. Dupuis, Katherine A. Dixon, Malea L. Williams, Kiersten L. Maldonado, Asif Rashid, Alda L. Tam. Generation and characterization of colorectal cancer cell lines from the Buffalo rat [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6136.

In vivo performance of gold nanoparticle-loaded absorbable inferior vena cava filters in a swine model

Absorbable inferior vena cava filters (IVCFs) offer a promising alternative to metallic retrievable filters in providing protection against pulmonary embolism (PE) for patients contraindicated for anticoagulant therapy. However, because absorbable filters are not radiopaque, monitoring of the filter using conventional X-ray imaging modalities (e.g. plain film radiographs, computed tomography [CT] and fluoroscopy) during deployment and follow-up is not possible and represents a potential obstacle to widespread clinical integration of the device. Here, we demonstrate that gold nanoparticles (AuNPs) infused into biodegradable filters made up of poly-p-dioxanone (PPDO) may improve device radiopacity without untoward effects on device efficacy and safety, as assessed in swine models for 12 weeks. The absorbable AuNP-infused filters demonstrated significantly improved visualization using CT without affecting tensile strength, in vitro degradation, in vivo resorption, or thrombus-capturing efficacy, as compared to similar non-AuNPs infused resorbable IVCFs. This study presents a significant advancement to the development of imaging enhancers for absorbable IVCFs.

A novel behavioral model of the pasture-based dairy cow from GPS data using data mining and machine learning techniques

A better understanding of the behavior of individual grazing dairy cattle will assist in improving productivity and welfare. Global positioning systems (GPS) applied to cows could provide a means of monitoring grazing herds while overcoming the substantial efforts required for manual observation. Any model of behavioral prediction using GPS needs to be accurate and robust by accounting for inter-cow variation as well as atmospheric effects. We evaluated the performance using a series of machine learning algorithms on GPS data collected from 40 pasture-based dairy cows over 4 mo. A feature extraction step was performed on the collected raw GPS data, which resulted in 43 different attributes. The evaluated behaviors were grazing, resting, and walking. Classifier learners were built using 10 times 10-fold cross validation and tested on an independent test set. Results were evaluated using a variety of statistical significance tests across all parameters. We found that final model selection depended upon level of performance and model complexity. The classifier learner deemed most suitable for this particular problem was JRip, a rule-based learner (classification accuracy=0.85; false positive rate=0.10; F-measure=0.76; area under the receiver operating curve=0.87). This model will be used in further studies to assess the behavior and welfare of pasture-based dairy cows.

Spatial epidemiology of Escherichia coli O157:H7 in dairy cattle in relation to night roosts Of Sturnus vulgaris (European Starling) in Ohio, USA (2007-2009)

The goal of our study was to use spatial scan statics to determine whether the night roosts of European starlings (Sturnus vulgaris) act as point sources for the dissemination of Escherichia coli O157:H7 among dairy farms. From 2007 to 2009, we collected bovine faecal samples (n = 9000) and starling gastrointestinal contents (n = 430) from 150 dairy farms in northeastern Ohio, USA. Isolates of E. coli O157:H7 recovered from these samples were subtyped using multilocus variable-number tandem repeat analysis (MLVA). Generated MLVA types were used to construct a dendrogram based on a categorical multistate coefficient and unweighted pair-group method with arithmetic mean (UPGMA). Using a focused spatial scan statistic, we identified statistically significant spatial clusters among dairy farms surrounding starling night roosts, with an increased prevalence of E. coli O157:H7-positive bovine faecal pats, increased diversity of distinguishable MLVA types and a greater number of isolates with MLVA types from bovine-starling clades versus bovine-only clades. Thus, our findings are compatible with the hypothesis that starlings have a role in the dissemination of E. coli O157:H7 among dairy farms, and further research into starling management is warranted.

A novel method of detection and classification of motor nerve late-wave activity

In motor nerve conduction studies, important diagnostic information is provided by the late-wave responses, comprised of F-waves, A-waves, and repeaters. Late-waves in addition to contamination from power line interference and baseline disturbance, are of low amplitude and random in nature. This makes computer-based analysis of late-wave activity very challenging, especially the computer-based F-wave onset latency assignment. Currently available algorithms assign latency independently on a trace-by-trace basis without considering the information present in an entire ensemble of traces. A novel algorithm that takes into account the ensemble information for segmenting and classifying regions of late-wave data is described in this paper, which in turn can be used to improve the performance of computer-based F-wave onset latency assignment.

Emotional intimacy predicts condom use: findings in a group at high sexually transmitted disease risk

Previous studies have reported an inverse relationship between condom use and emotional intimacy. The aim of this study was to determine the relationship between condom use and emotional intimacy. The study was a gonorrhoea case-comparison study with the samples being drawn from public health clinics (cases) and select bars/nightclubs (places) of Houston, TX ( n = 215). Data were collected by questionnaires administered on a laptop computer. The majority of respondents were African-American (97.7%), women (69.3%) and had either high school or GED education (72.6%). Condom use with the last sexual partner was analysed along with intimacy with that partner assessed on a 3-point scale. Analysis showed that higher intimacy was related to greater condom use which was significant in men but not in women. In conclusion, these data were opposite to those of previous studies, which showed an inverse relationship between condom use and emotional intimacy. We hypothesize that in a high-risk environment, people exert more effort in protecting those they feel closer to. These data suggest a need to further explore the complex relationship between emotional intimacy and condom use.

Personal and partner measures in stages of consistent condom use among African-American heterosexual crack cocaine smokers

Participants' personal condom use measures and those of their last sex partner's were examined in five stages of change for consistent condom use among 449 urban sexually active, heterosexual, African-American crack smokers. The measures included participants' personal and their last sex partner's perceived responsibility, personal and perceived negative attitudes, and participants' self-efficacy to use condoms. The relationships between the measures and the stages were examined using analyses of variance and multivariate logistic regression. Over 90% of participants did not use condoms, consistently. Two-thirds of the inconsistent users were in the precontemplation stage. The rest were equally divided between the contemplation and preparation stages. Personal responsibility outperformed other measures in initial intention to become a regular condom user; partner's perceived responsibility dominated continued intention and actual consistent condom use. Negative attitudes and self-efficacies had strong relationships to the stages of consistent condom use in univariate analyses but these relationships became substantially weaker when the responsibility, attitude, and self-efficacy concepts were entered simultaneously into multivariate analyses.

Associations among correlates of schedule adherence to antiretroviral therapy (ART): a path analysis of a sample of crack cocaine using sexually active African-Americans with HIV infection

Adherence to HIV medication regimens is a function of multiple dimensions including psychological functioning, social support, adherence self-efficacy and optimism regarding treatment. Active substance use can also negatively affect adherence. An understanding of the nature of the associations among the correlates of adherence can better inform the design of interventions to improve adherence. This study developed an exploratory path model of schedule adherence using data from a sample 130 African-American HIV-positive crack cocaine users on highly active antiretroviral therapy (ART). This model was based on the Transactional Model of Stress and Coping developed by Lazarus and Folkman. Following the theory, the effects of psychological distress on schedule adherence were mediated by patients' relationship with their doctor and optimism towards antiretroviral treatment. Adherence was also associated with patients' self-efficacy regarding their medical regimen which, in turn, was associated with their social support.

Characterization of the rrn operons in the channel catfish pathogen Edwardsiella ictaluri

AIMS

To advance diagnostics and phylogenetics of Edwardsiella ictaluri by sequencing and characterizing its rrn operons.

METHODS AND RESULTS

The Edw. ictaluri rrn operons were identified from a 5-7 kbp insert lambda library and from Edw. ictaluri fosmid clones. We present the complete sequences and analysis of all eight Edw. ictaluri rrn operons and unique regions located upstream and downstream. Two rrn operons were located in tandem with 169 bp separating them, which is apparently a conserved feature between Edw. ictaluri and Edwardsiella tarda. I-CeuI enzyme digestion of Edw. ictaluri genomic DNA and analysis by pulsed field gel electrophoresis indicated that rrn operon number and chromosomal locations are conserved within the species Edw. ictaluri.

CONCLUSIONS

The rrn operons of Edw. ictaluri have similar structure and flanking regions compared with other members of the family Enterobacteriaceae; however, the presence of eight copies of the rrn operon makes Edw. ictaluri unique within the family.

SIGNIFICANCE AND IMPACT OF THE STUDY

This research clarifies previous phylogenetic analyses of Edw. ictaluri and provides support for the Edw. ictaluri genome sequencing project. In addition, we identified a unique feature of two rrn operons that shows potential for the development of a diagnostic PCR method.

Process, efficacy and sample demographics of three approaches to behavioural surveillance for gonorrhoea: case interviews, place surveys, and network studies

We investigated the process and time required to collect 450 interviews in a project to determine the most efficacious behavioural surveillance approaches to detect changes in gonorrhoea prevalence. In total, 150 respondents were recruited in each method. For each of place surveys (bars), gonorrhoea case interviews, and network studies based on seeds from the case and place interviews, we determined the recruitment rate and process. Urine testing for gonorrhoea and chlamydia took place in the place interviews. We present data from Houston, Texas that illustrate the sample characteristics, recruitment rates, and, where appropriate, infection rates. Data indicate that there was high uptake and a rapid recruitment rate from the place surveys, an intermediate rate from the network studies, and that the gonorrhoea case interviews were the most inefficient accrual method for behavioural surveillance. Sample characteristics and biases in each method are described, and conclusions drawn for the relative efficacy of each method for gonorrhoea behavioural surveillance.

Tuberculosis infection in drug users: interferon-gamma release assay performance

SETTING

An inner city neighborhood in Houston, Texas, known for a high rate of drug use.

OBJECTIVE

To determine the prevalence of latent tuberculosis infection (LTBI) using the QuantiFERON-TB Gold (QFT-G) test, the TSPOT.TB test and the tuberculin skin test (TST) in drug users and to evaluate the performance of the QFT-G and TSPOT.TB tests vs. the TST.

DESIGN

Cross-sectional study. Bivariate and multivariate logistic regression analyses were used to determine risks associated with each test outcome.

RESULTS

The prevalence of LTBI in 119 drug users studied was 28% by TST and 34% by QFT-G and T-SPOT.TB. Kappa statistics indicated fair to moderate concordance between QFT-G and TSPOT.TB vs. TST. About one-fifth of the population that tested negative with TST was positive with either QFT-G or T-SPOT.TB. On multivariate analysis, the likelihood of testing QFT-positive or T-SPOT.TB-positive increased by 8% and 6%, respectively, for every year of age; TST positivity was associated with smoking crack at home; being Caucasian or having a history of alcohol use was positively associated with a positive T-SPOT.TB test.

CONCLUSION

Interferon-gamma release assays (IGRAs) are superior to the TST in drug users with a higher prevalence of LTBI. Future studies need to assess the predictive value of IGRAs on the progression from LTBI to active TB in high-risk populations.

The impact of HIV-related interventions on HIV risk behavior in a community sample of African American crack cocaine users

While there are reports of the impact of specific interventions designed to reduce HIV drug and sexual risk behaviors, there are few reports of the impact of HIV interventions in a community-based sample. We report on baseline data from a sample of African American crack smokers who were about to participate in an intervention designed to reduce HIV-related risk behaviors. The majority were male (80%), single (70%) and homeless (52%). Data indicated that 29% of the sample had been in a previous HIV intervention in the past 12 months, the majority in a correctional setting or CBO program. There were few systematic demographic differences between the two groups. Those who had been in an intervention reported using male and female condoms significantly more frequently on all measures of condom use, had positive condom use outcome expectations for male condoms and higher affective and situational condom-related self-efficacy beliefs. These data suggest that, at a community level, the spectrum of HIV risk-reduction programs does produce a significant improvement in condom use and related cognitions, although there is a need to cover a greater proportion of the population. Previous exposure to interventions must be a critical covariate in assessing the impact of future interventions.

Responsibility as a dimension of HIV prevention normative beliefs: measurement in three drug-using samples

The concept of responsibility was derived originally from principles of morality, as part of a network of rights, duties and obligations. HIV risk-related studies have suggested that a sense of responsibility for condom use to protect a partner is a potentially important predictor of condom use in drug-using populations. We created a four-item scale measuring Self responsibility to use condoms and Partner's responsibility to use condoms. Data were collected from three drug-using samples: crack smokers, HIV seropositive crack smokers in an intervention study in Houston, Texas, and Tanzanian heroin users in Dar es Salaam. Data indicated that the four responsibility items had high alpha coefficients in each sample, and that there were moderate to high intercorrelations between equivalent self and partner responsibility items. There were significant differences in scale scores between the crack smokers and the HIV positive crack smokers and the Tanzanian samples, but no significant differences between the HIV positive and Tanzanian samples. Comparing within the first crack-smoker sample those who were HIV positive and negative showed significant differences in the direction of higher beliefs in responsibility to use condoms in the HIV positive group. These data suggest that responsibility is measurable, holds similar psychometric properties across three samples differing in culture and HIV serostatus, and that condom use responsibility is conceptualized as a measure of general responsibility rather than as a reciprocal self/partner responsibility.

Heroin and HIV risk in Dar es Salaam, Tanzania: Youth hangouts, mageto and injecting practices

HIV risk through needle sharing is now an emerging phenomenon in Africa. This article describes the practices that heroin users are producing as they establish the rules and organization surrounding their drug use. Their practices and interactions reveal the ways that they become initiated into its use, how they progress to injecting, and the important role of local neighbourhood hangouts in facilitating this process. Their practices, interactions and narratives also provide insights into what may be the most appropriate HIV-prevention interventions. Semi-structured interviews were conducted during the months of February and July 2003 with 51 male and female injectors residing in 8 neighbourhoods in the Dar es Salaam, Tanzania. Interviews were content coded and codes were collapsed into emergent themes around hangout places, initiation of heroin use, and progression to injecting. Interviews reveal that Dar es Salaam injectors begin smoking heroin in hangout areas with their friends, either because of peer pressure, desire, or trickery. One hangout place in particular, referred to as the 'geto' (ghetto) is the main place where the organization and rules governing heroin use are produced. Three main types of heroin 'ghettoes' are operating in Dar es Salaam. As users build a tolerance for the drug they move along a continuum of practices until they begin to inject. Injecting heroin is a comparatively recent practice in Africa and coincides with: (1) Tanzania transitioning to becoming a heroin consuming community; (2) the growing importance of youth culture; (3) the technical innovation of injecting practices and the introduction and ease of use of white heroin; and (4) heroin smokers, sniffers, and inhalers perceived need to escalate their use through a more effective and satisfying form of heroin ingestion.

Identification and characterization of a two-component hemolysin from Edwardsiella ictaluri

The channel catfish pathogen Edwardsiella ictaluri possesses hemolysin activity, and strains that are adapted for growth in fish tend to have greater hemolysin activity than strains that are adapted for in vitro growth conditions. To investigate its potential role in virulence, an isogenic hemolysin mutant strain of E. ictaluri R4383 was constructed by transposon mutagenesis. Sequencing of the chromosomal insertion site identified two genes, designated eihA and eihB, that encode proteins with homology to the Serratia family of two-component hemolysins. EihB is similar to the secretion/activation proteins from this family, and EihA is similar to the cytolysin proteins from this family. Bacterial challenge in channel catfish fingerlings did not show a significant difference in virulence between the wild type E. ictaluri strain and the hemolysin deficient E. ictaluri mutant strain.

The Relationship Between a Urinary Cachectic Factor and Weight Loss in Advanced Cancer Patients

A 24K glycoprotein, the proteolysis-inducing factor (PIF), has been identified in mice and humans with cancer cachexia. Clinical cross-sectional studies found an association between the presence of PIF in urine and tumors of patients and weight loss. For the first time, we report results from a longitudinal study establishing the relationship between a urinary PIF pattern and persistent weight loss. Over time, cancer patients positive for the PIF pattern experienced weight loss, whereas those with a negative test gained weight.

Psychosocial factors associated with adherence to antiretroviral medications in a sample of HIV-positive African American drug users

The purpose of the study was to investigate factors affecting antiretroviral adherence among African American drug users, specifically to identify associations between self-reported adherence levels and psychosocial measures selected with guidance from the Transactional Model of Stress and Coping (TMSC). The study was conducted using data collected from 137 HIV-positive African American drug users who were receiving antiretroviral medications at the time they were interviewed. Bivariate associations were investigated using correlational analyses and variables showing a significant correlation with adherence were entered into a multivariate regression model. The multivariate model showed only perceived efficacy of antiretrovirals and one measure of perceived barriers, simply forgetting to take medications, were independently related to adherence. These preliminary findings suggest that theoretical approaches to understanding antiretroviral adherence must address a range of variables, including but not limited to behavioural practices, cognitive appraisals, affective responses and social support. Further studies using the complete TMSC are recommended.

Paediatric outreach services

Paediatric outreach services are provided in Australia and overseas to regional and rural communities. More recently telehealth services have been established to support the delivery of paediatric services and clinical management at distant sites. It is suggested that with the large distances separating centres in Australia that a combination of telehealth clinics and outreach visits may provide the most efficient means of delivering paediatric specialty and subspecialty care to these centres.

Deterministic photon transport calculations in general geometry for external beam radiation therapy

A deterministic method is described for performing three-dimensional (3D) photon transport calculations of a LINAC head and phantom/patient geometry to obtain dose distributions for therapy planning. The space, energy, and directional-dependent photon flux density is obtained by numerically solving the Boltzmann equation in general 3D geometry using the method of characteristics. The deterministic transport calculations use similar ray tracing routines as found in Monte Carlo (MC) codes. A special treatment is developed to better represent the impact of scattering from accelerator head components. Equations are presented for computing the water kerma distribution due to the uncollided and collided photon flux density field in the patient region. Kerma results obtained from the deterministic computation are compared to Monte Carlo values for a variety of source spectra and field sizes. The agreement for kerma values in the beam is usually within the MC uncertainties. It is concluded that the deterministic method is a rigorous, first-principles approach that could provide a superior alternative to Monte Carlo calculations for some types of problems. However additional development is needed to provide capability for 3D electron transport calculations.

Sexual behavior and illicit drug use

Sexual behavior in drug users varies in association with the drug used, the drug subculture and setting, and the need to maintain the drug addiction. We review the literature on sexual behavior in drug-using subcultures, most of which centers on HIV risk reduction, and the drug-associated and economic pressures that influence sexual behavior. Most data available are on opioid (predominantly heroin) users and crack cocaine users. The recent phenomenon of the circuit party has led to investigation of the context in which drug use and sex have become the focus of large gay-oriented parties over long weekends. Sexual behavior in association with drugs in Western societies is important for its role in the spread of sexually transmissible pathogens, as well as injection-related pathogens.

High-density EEG mapping during general anaesthesia with xenon and propofol: a pilot study

Anaesthetic-induced spatial inhomogeneities of the electrencephalogram(EEG) using "high density" electrode mapping have not previously been reported. We measured the scalp EEG with a dense electrode (128-channel) montage during the course of light general anaesthesia with xenon and then propofol in normal human subjects. EEG was measured during induction and recovery of general anaesthesia in five normal subjects, and we obtained analysable data from three of these subjects. EEG topographies were plotted on a realistic head surface. Scalp fields were spatially de-blurred using a realistic head model and projected onto an averaged cortical surface Both xenon and propofol elicited large increases in midline frontal theta-band EEG power. Propofol reliably elicited orbitofrontal delta activity. Xenon, but not propofol, caused large increases in delta over the posterior cortex. Increased gamma power was observed for both anaesthetic agents at midline electrodes over the posterior cortex, but not anteriorly. Anaesthesia-induced delta and theta waves were differentially distributed along the anterior-posterior axis of the brain in a manner that corresponds well to the anatomy of putative neuronal generators. The distribution of anaesthetic-induced changes in fast gamma-band power seems to reflect functional differences between the posterior and anterior aspects of the cerebral cortex. These preliminary observations were consistent within our small sample, indicating that larger studies of anaesthetic effects using high-density recordings are warranted.

Deterministic calculations of photon spectra for clinical accelerator targets

A method is proposed to compute photon energy spectra produced in clinical electron accelerator targets, based on the deterministic solution of the Boltzmann equation for coupled electron-photon transport in one-dimensional (1-D) slab geometry. It is shown that the deterministic method gives similar results as Monte Carlo calculations over the angular range of interest for therapy applications. Relative energy spectra computed by deterministic and 3-D Monte Carlo methods, respectively, are compared for several realistic target materials and different electron beams, and are found to give similar photon energy distributions and mean energies. The deterministic calculations typically require 1-2 mins of execution time on a Sun Workstation, compared to 2-36 h for the Monte Carlo runs.

What is the 'true' function of skin?

Conventional textbook wisdom portrays the skin as an organ that literally enwraps whatever each of us stands for as a more or less functional, individual member of the mammalian species, and has it that the skin primarily establishes, controls and transmits contacts with the external world. In addition, the skin has long been recognized to protect the organism from deleterious environmental impacts (physical, chemical,microbiological), and is well-known as crucial for the maintenance of temperature, electrolyte and fluid balance. Now, ever more studies are being published that show the skin to also operate as a huge and highly active biofactory for the synthesis,processing and/or metabolism of an astounding range of e.g. structural proteins, glycans, lipids and signaling molecules. Increasingly, it becomes appreciated that the skin, furthermore, is an integral component of the immune, nervous and endocrine systems, with numerous lines of cross-talk between these systems established intracutaneously (e.g. Ann NY Acad Sci Vol 885, 1999; Endocrine Rev 21:457-487, 2000; Physiol Rev 80:980-1020, 2001; Exp Dermatol 10: 349-367, 2001). All these emerging cutaneous functions beyond the classical image of the skin as a barrier and sensory organ are immediately relevant for many of the quandaries that clinical dermatology, dermatopathology, and dermatopharmacology are still struggling with to-date, and offer the practising dermatologist attractive new targets for therapeutic intervention. Yet, many of these skin functions are not even mentioned in dermatology textbooks and await systematic therapeutic targeting. Following a suggestion by Enno Christophers, the current 'Controversies' feature brings together an unusually diverse council of biologists and clinicians, who share their thought-provoking views with the readers and allow us to peek into the future of research in cutaneous biology, not the least by reminding us of the -- often ignored -- evolutionary and embryonal origins of our favorite organ. Hopefully, this unique discussion feature will foster an understanding of the 'true' skin functions that is both more comprehensive and more profound than conventional teaching on this topic, and will stimulate more than 'skin-deep' reflections on the full range of skin functions.

Acute myocardial infarction at a university hospital: effect of race on short-term mortality

Several studies have shown that African Americans who have an acute myocardial infarction (AMI) have a higher mortality rate and receive less aggressive cardiac intervention compared with whites. This observational study reports on the in-hospital mortality rate for AMI by race at a university tertiary referral hospital. Racial variation in clinical outcomes and treatment in the area of thrombolysis and acute revascularization was assessed. Data were retrieved from the National Registry on Myocardial Infarction (NRMI) for all 521 patients with AMI admitted to the critical care unit at the University of North Carolina between January 1991 and December 1994. Information collected included age, gender, race, cardiac catheterization results, thrombolytic therapy, coronary bypass surgery, mortality, and arrhythmia. African Americans had a lower in-hospital mortality rate compared with whites (2% versus 8% P < or = 0.03) and were also younger (61 +/- 13 SD versus 64 +/- 12 P = 0.02). Hypertension, diabetes mellitus, or prior myocardial infarction were similar in both groups. Of the 323 patients who received a cardiac catheterization, the extent of coronary disease and left ventricular ejection fraction was similar in both races. Finally, the use of thrombolysis, PTCA, or CABG was not influenced by race. In conclusion, the in-hospital mortality for African Americans at this university tertiary referral center was lower than for whites. This occurred despite a similar incidence in cardiac risk factors and similarly aggressive acute cardiac interventions in both white and African American patients. While African Americans experienced lower in-hospital mortality, this study does not address the pre-hospital and post-hospital risk. It does suggest that African Americans with AMI, who are comparably matched to whites for risk and receive similar cardiac interventions, may have a favorable in-hospital mortality.

Gender differences in the processes of change for condom use: patterns across stages of change in crack cocaine users

Interventions to increase condom use in crack users have had mixed results. For interventions to achieve greater success, the mechanisms of behavior change in this population need to be understood. One mechanism, the processes of change, was examined across stages of change for condom use. Results from the analysis of variance for males and females revealed that stage of change was associated with different levels of three experiential processes: consciousness raising, social liberation and self-reevaluation. However, these analyses found that male and females seem to have different patterns of behavioral process use. Specifically, females in the preparation stage were different from those in precontemplation, whereas this difference was not pronounced in males. In general, people had high levels of experimental processes in every stage of change. The patterns of behavior process use mimicked patterns found for other behaviors with a linear increase across the stages of change. This may indicate that for maintaining condom use, more emotional and behavioral activities are required throughout the process of acquisition and maintenance than are necessary for other health-related activities. Implications of this research are that interventions for increasing condom use in drug users may target behavioral steps differently for males and females.

Pathogenesis of the permeability barrier abnormality in epidermolytic hyperkeratosis

Epidermolytic hyperkeratosis is a dominantly inherited ichthyosis, frequently associated with mutations in keratin 1 or 10 that result in disruption of the keratin filament cytoskeleton leading to keratinocyte fragility. In addition to blistering and a severe disorder of cornification, patients typically display an abnormality in permeability barrier function. The nature and pathogenesis of the barrier abnormality in epidermolytic hyperkeratosis are unknown, however. We assessed here, first, baseline transepidermal water loss and barrier recovery kinetics in patients with epidermolytic hyperkeratosis. Whereas baseline transepidermal water loss rates were elevated by approximately 3-fold, recovery rates were faster in epidermolytic hyperkeratosis than in age-matched controls. Electron microscopy showed no defect in either the cornified envelope or the adjacent cornified-bound lipid envelope, i.e., a corneocyte scaffold abnormality does not explain the barrier abnormality. Using the water-soluble tracer, colloidal lanthanum, there was no evidence of tracer accumulation in corneocytes, despite the fragility of nucleated keratinocytes. Instead, tracer, which was excluded in normal skin, moved through the extracellular stratum corneum domains. Increasing intercellular permeability correlated with decreased quantities and defective organization of extracellular lamellar bilayers. The decreased lamellar material, in turn, could be attributed to incompletely secreted lamellar bodies within granular cells, demonstrable not only by several morphologic findings, but also by decreased delivery of a lamellar body content marker, acid lipase, to the stratum corneum interstices. Yet, after acute barrier disruption a rapid release of preformed lamellar body contents was observed together with increased organelle contents in the extracellular spaces, accounting for the accelerated recovery kinetics in epidermolytic hyperkeratosis. Accelerated recovery, in turn, correlated with a restoration in calcium in outer stratum granulosum cells in epidermolytic hyperkeratosis after barrier disruption. Thus, the baseline permeability barrier abnormality in epidermolytic hyperkeratosis can be attributed to abnormal lamellar body secretion, rather than to corneocyte fragility or an abnormal cornified envelope/cornified-bound lipid envelope scaffold, a defect that can be overcome by external applications of stimuli for barrier repair.

The spectrum of pathogenic mutations in SPINK5 in 19 families with Netherton syndrome: implications for mutation detection and first case of prenatal diagnosis

The Comèl-Netherton syndrome is an autosomal recessive multisystemic disorder characterized by localized or generalized congenital ichthyosis, hair shaft abnormalities, immune deficiency, and markedly elevated IgE levels. Life-threatening complications during infancy include temperature and electrolyte imbalance, recurrent infections, and failure to thrive. To study the clinical presentations of the Comèl-Netherton syndrome and its molecular cause, we ascertained 19 unrelated families of various ethnic backgrounds. Results of initial linkage studies mapped the Comèl-Netherton syndrome in 12 multiplex families to a 12 cM interval on 5q32, thus confirming genetic homogeneity of Comèl-Netherton syndrome across families of different origins. The Comèl-Netherton syndrome region harbors the SPINK5 gene, which encodes a multidomain serine protease inhibitor (LEKTI) predominantly expressed in epithelial and lymphoid tissues. Recently, recessive mutations in SPINK5 were identified in several Comèl-Netherton syndrome patients from consanguineous families. We used heteroduplex analysis followed by direct DNA sequencing to screen all 33 exons and flanking intronic sequences of SPINK5 in the affected individuals of our cohort. Mutation analysis revealed 17 distinct mutations, 15 of which were novel, segregating in 14 Comèl-Netherton syndrome families. The nucleotide changes included four non-sense mutations, eight small deletions or insertions leading to frameshift, and five splice site defects, all of which are expected to result in premature terminated or altered translation of SPINK5. Almost half of the mutations clustered between exons 2 and 8, including two recurrent mutations. Genotype-phenotype correlations suggested that homozygous nucleotide changes resulting in early truncation of LEKT1 are associated with a severe phenotype. For the first time, we used molecular data to perform prenatal testing, thus demonstrating the feasibility of molecular diagnosis in the Comèl-Netherton syndrome.

Cutaneous manifestations of maternal engraftment in patients with severe combined immunodeficiency: a clinicopathologic study

SCID is a heterogeneous group of disorders characterized by defective T cell and B cell function. Eczematous and morbilliform eruptions are common, and graft-versus-host disease (GVHD) due to maternal engraftment has been documented. We sought to better characterize SCID-related cutaneous disease observed prior to BMT and to compare the eruption to conventional GVHD. Medical records of 51 patients with SCID treated between 1982 and 1999 were reviewed. Ten of 51 (20%) had rash and evidence of maternal engraftment prior to BMT (study group). Eleven of 51 (22%) had no rash or evidence of engraftment pre-BMT but developed GVHD following transplant (control group). Skin biopsies were available for review for 8/10 of the study group and for 8/11 of the control group. Cutaneous findings consisted of a scaling, erythematous maculopapular eruption spread widely over the trunk and extremities, with near-erythroderma in some patients. Microscopically, biopsies from the study group differed significantly from controls. Key differences included parakeratosis (P < or = 0.01), psoriasiform hyperplasia (P < or = 0.04) and spongiosis (P < or = 0.04). The dermatopathologic findings of transplacental GVHD differ from the pattern of post-transplant GVHD. A 'psoriasiform-lichenoid-spongiotic' pattern with necrotic keratinocytes should trigger consideration of SCID and maternal engraftment in the dermatopathologic evaluation of eruptions of infancy.

Significant absorption of topical tacrolimus in 3 patients with Netherton syndrome

BACKGROUND

Tacrolimus is a macrolide immunosuppressant approved in oral and intravenous formulations for primary immunosuppression in liver and kidney transplantation. Topical 0.1% tacrolimus ointment has recently been shown to be effective in atopic dermatitis for children as young as 2 years of age, with minimal systemic absorption. We describe 3 patients treated with topical 0.1% tacrolimus who developed significant systemic absorption.

OBSERVATION

Three patients previously diagnosed as having Netherton syndrome were treated at different centers with 0.1% tacrolimus ointment twice daily. Two patients showed dramatic improvement. All patients were found to have tacrolimus blood levels within or above the established therapeutic trough range for oral tacrolimus in organ transplant recipients. None of these patients developed signs or symptoms of toxic effects of tacrolimus.

CONCLUSIONS

Patients with Netherton syndrome have a skin barrier dysfunction that puts them at risk for increased percutaneous absorption. The Food and Drug Administration recently approved 0.1% tacrolimus ointment for the treatment of atopic dermatitis. Children with Netherton syndrome may be misdiagnosed as having atopic dermatitis. These children are at risk for marked systemic absorption and associated toxic effects. If topical tacrolimus is used in this setting, monitoring of serum tacrolimus levels is essential.

Pigmented lesions in adolescents

Accurate diagnosis of congenital and acquired pigmented lesions accompanied by an understanding of their natural history and disease associations is critical for the appropriate management and counseling of adolescents, as well as timely referral to specialists when indicated. The recognition of atypical nevi and other melanoma risk factors in adolescents should lead to institution of preventive measures, such as routine skin examinations and counseling regarding sun protection. Because the incidence of melanoma is increasing in adolescents as well as adults, prompt identification of suspicious melanocytic lesions may lead to early diagnosis and effective treatment of melanoma. Numerous pigmented lesions can also herald the presence of a multisystem disorder; the recognition of syndromes associated with these lesions should result in appropriate evaluation and genetic counseling of affected individuals. This review distinguishes pigmented lesions that histologically represent a proliferation of melanocytes and that may therefore confer an increased risk for melanoma, from pigmented lesions due to increased melanization alone (i.e., increased melanin content) that are not associated with malignancy.

Effects of dietary curcumin on glutathione S-transferase and malondialdehyde-DNA adducts in rat liver and colon mucosa: relationship with drug levels

Curcumin prevents colon cancer in rodent models. It inhibits lipid peroxidation and cyclooxygenase-2 (COX-2) expression and induces glutathione S-transferase (GST) enzymes. We tested the hypothesis that 14 days of dietary curcumin (2%) affects biomarkers relevant to cancer chemoprevention in the rat. Levels of inducible COX-2, as reflected by prostaglandin E(2) production by blood leukocytes, were measured ex vivo. Total GST activity and adducts of malondialdehyde with DNA (M(1)G), which reflect endogenous lipid peroxidation, were measured in colon mucosa, liver, and blood leukocytes. Curcumin and its metabolites were analyzed by high-performance liquid chromatography in plasma, and its pharmacokinetics were compared following a diet containing 2% curcumin versus intragastric (i.g.) administration of curcumin suspended in an amphiphilic solvent. The curcumin diet did not alter any of the markers in the blood but increased hepatic GST by 16% and decreased colon M(1)G levels by 36% when compared with controls. Administration of carbon tetrachloride during the treatment period increased colon M(1)G levels, and this increase was prevented by dietary curcumin. Dietary curcumin yielded low drug levels in the plasma, between 0 and 12 nM, whereas tissue concentrations of curcumin in liver and colon mucosa were 0.1--0.9 nmol/g and 0.2--1.8 micromol/g, respectively. In comparison with dietary administration, suspended curcumin given i.g. resulted in more curcumin in the plasma but much less in the colon mucosa. The results show that curcumin mixed with the diet achieves drug levels in the colon and liver sufficient to explain the pharmacological activities observed and suggest that this mode of administration may be preferable for the chemoprevention of colon cancer.

Giant congenital melanocytic nevi: the significance of neurocutaneous melanosis in neurologically asymptomatic children

Patients with a giant congenital melanocytic nevus can develop melanotic tumors characterized by central nervous system involvement, termed leptomeningeal melanocytosis or neurocutaneous melanosis. Although symptomatic neurocutaneous melanosis is rare, we previously reported distinct magnetic resonance (MR) findings of T1 shortening, strongly suggestive of neurocutaneous melanosis, in 30 percent (6 of 20) of children with giant congenital melanocytic nevi who presented initially without neurological symptoms. The purpose of this study was to determine the incidence of neurocutaneous melanosis in high-risk patients and its long-term clinical significance. Magnetic resonance imaging was recommended for all 46 patients with "at-risk" giant congenital melanocytic nevi involving the skin overlying the dorsal spine or scalp. The clinical histories and follow-up of these patients were evaluated by retrospective chart review. Forty-two underwent MR imaging of the brain and 11 underwent additional MR scanning of the spinal cord. Abnormalities were identified in 14 of 43 MR studies, and 23 percent (n = 10) had T1 shortening indicative of melanotic rests within the brain or meninges. None had associated masses or leptomeningeal thickening. The most common areas of involvement in these 10 included the amygdala (n = 8), cerebellum (n = 5), and pons (n = 3). In the group of 11 patients with spinal MR scans, a tethered spinal cord was demonstrated in one. Additional abnormalities were detected by MR scanning, including a middle cranial fossa arachnoid cyst, a Chiari type I malformation, and a crescentic enhancement that subsequently resolved. Clinical follow-up averaging 5 years (range, 2 to 8 years) revealed that only one of the 46 patients evaluated developed neurological symptoms, manifested as developmental delay, hypotonia, and questionable seizures but no other signs of neurocutaneous melanosis. No patient has developed a cutaneous or central nervous system melanoma. Magnetic resonance findings of neurocutaneous melanosis are relatively common, even in asymptomatic children with giant congenital melanocytic nevi. Although these findings suggest an increased lifetime risk of central nervous system melanoma, they do not signify the eventual development of symptomatic neurocutaneous melanosis during childhood.

Cholesterol sulfate stimulates involucrin transcription in keratinocytes by increasing Fra-1, Fra-2, and Jun D

Lipids that are synthesized de novo in the epidermis, including fatty acids, oxysterols, 1,25-dihydroxyvitamin D(3), and farnesol, can regulate the differentiation of normal human keratinocytes (NHK). Cholesterol sulfate (CS), an epidermal lipid that is produced in the upper nucleated layers of the epidermis coincident with terminal differentiation, has been shown to play a role in the regulation of the late stages of keratinocyte differentiation, including formation of the cornified envelope. In the present study, we determined i) whether CS regulates involucrin (INV), an early keratinocyte differentiation marker, and ii) the mechanism by which CS regulates differentiation. mRNA and protein levels of INV, a precursor protein of the cornified envelope, increased 2- to 3-fold in NHK incubated in the presence of CS. In contrast, cholesterol had no effect on INV protein or mRNA levels. Transcriptional regulation was assessed in NHK transfected with INV promoter-luciferase constructs. CS increased luciferase reporter activity approximately 2- to 3-fold in NHK transfected with a 3.7-kb INV promoter construct. Deletional analysis revealed a CS-responsive region of the INV promoter located between bp --2452 and --1880. A 5-base pair (bp) mutation of the AP-1 site (bp --2117 to --2111) within this responsive region abolished CS responsiveness, suggesting a role for the AP-1 complex in the regulation of INV transcription by CS. Electrophoretic mobility shift analysis demonstrated increased binding of nuclear extracts isolated from CS-treated NHK to AP-1 DNA as compared with vehicle-treated controls. Incubation of the nuclear extract with the appropriate antibodies showed that the AP-1 DNA-binding complex contained Fra-1, Fra-2, and Jun D. Western blots demonstrated that CS treatment increased the levels of Fra-1, Fra-2, and Jun D, and Northern analyses revealed that CS increased mRNA levels for these same AP-1 factors. These data indicate that CS, an endogenous lipid synthesized by keratinocytes, regulates the early stages of keratinocyte differentiation, and may do so through its ability to modulate levels of AP-1 proteins. -- Hanley, K., L. Wood, D. C. Ng, S. S. He, P. Lau, A. Moser, P. M. Elias, D. D. Bikle, M. L. Williams, and K. R. Feingold. Cholesterol sulfate stimulates involucrin transcription in keratinocytes by increasing Fra-1, Fra-2, and Jun D. J. Lipid Res. 2001. 42: 390--398.

Comparison of changes in electroencephalographic measures during induction of general anaesthesia: influence of the gamma frequency band and electromyogram signal

Recent research has shown that high-frequency, gamma-band electroencephalographic (EEG) oscillations (40-60 Hz) may be an important marker of the conscious state. We compared the ability of the bispectral index (BIS) to distinguish the awake and anaesthetized states during the induction of general anaesthesia with: (i) components of the BIS (BetaRatio, SynchFastSlow); (ii) a new EEG variable--the median frequency of the first time derivative of the EEG signal (SE50d); and (iii) the SE50d derived from an EEG signal that has had the frequencies above 30 Hz removed (SE50d(30Hz)). Two groups of subjects were studied: (i) nine volunteers undergoing a short propofol infusion until loss of response to verbal command, and (ii) 84 patients undergoing routine anaesthesia for a variety of surgical procedures. In the volunteer group, the changes in the BetaRatio and SE50d were comparable with changes in the BIS. The changes in the SE50d(30Hz) were less consistent. In the patient group, the BIS components were equivalent to the BIS in separating the awake from the surgically anaesthetized states (area under receiver operating curve: BIS 0.95, SE50d 0.95, BetaRatio 0.96). Using the submental electromyogram (EMG) signal to estimate the frontalis EMG (30-47 Hz) signal, the changes in EMG signal were, on average, about one-tenth the magnitude of the EEG. We conclude that: (i) there exist simpler derived EEG variables that are similar in accuracy to the BIS; (ii) it is important to avoid filtering out the EEG frequencies above 30 Hz; and (iii) in most patients the confounding effects of the frontalis EMG on the EEG are minimal.

Keratinocyte differentiation in hyperproliferative epidermis: topical application of PPARalpha activators restores tissue homeostasis

We recently showed that topically applied PPARalpha activators promote epidermal differentiation in intact adult mouse skin. In this study we determined the effect of clofibrate and Wy-14,643, activators of PPARalpha, on hyperproliferative epidermis in hairless mice, induced either by repeated barrier abrogation (subacute model) or by essential fatty acid deficiency (chronic model). The hyperproliferative epidermis was characterized by an increased number of proliferating cells expressing proliferating cell nuclear antigen. Topical treatment with PPARalpha activators resulted in a substantial decrease in epidermal hyperplasia in both the subacute and chronic models of hyperproliferation. Following topical treatment, proliferating cell nuclear antigen-expressing cells were restricted to the basal layer, similar to normal epidermis. In hyperproliferative epidermis there was decreased expression of involucrin, profilaggrin-filaggrin, and loricrin as assayed by in situ hybridization and immunohistochemistry. Following topical treatment with PPAR activators staining for these mRNAs and proteins increased towards normal levels. Finally, topically applied clofibrate also increased apoptosis. This study demonstrates that topical PPAR activators have profound effects on epidermal gene expression in hyperproliferative skin disorders. Treatment with PPARalpha activators normalizes cell proliferation and promotes epidermal differentiation, correcting the cutaneous pathology. This study identifies PPARalpha activators as potential skin therapeutic agents.

Stimulation of PPARalpha promotes epidermal keratinocyte differentiation in vivo

Our recent studies have demonstrated that PPARalpha activators stimulate differentiation and inhibit proliferation in cultured human keratinocytes and accelerate epidermal development and permeability barrier formation in fetal rat skin explants. As the role of PPARalpha activation in adult epidermis is not known, the aim of this study was to determine if topically applied PPARalpha ligands regulate keratinocyte differentiation in murine epidermis. Topical treatment with PPARalpha activators resulted in decreased epidermal thickness. Expression of structural proteins of the upper spinous/granular layers (involucrin, profilaggrin-filaggrin, loricrin) increased following topical treatment with PPARalpha activators. Furthermore, topically applied PPARalpha activators also increased apoptosis, decreased cell proliferation, and accelerated recovery of barrier function following acute barrier abrogation. Experiments with PPARalpha-/- knockout mice showed that these effects are specifically mediated via PPARalpha. Compared with the epidermis of PPARalpha+/+ mice, involucrin, profilaggrin-filaggrin, and loricrin expression were slightly decreased in PPARalpha-/- mice. Moreover, topical clofibrate treatment did not increase epidermal differentiation in PPARalpha-/- mice. Furthermore, in cultured human keratinocytes we have demonstrated that PPARalpha activators induce an increase in involucrin mRNA levels. We have also shown that this increase in gene expression requires an intact AP-1 response element at -2117 to -2111 bp. Thus, stimulation of PPARalpha stimulates keratinocyte/epidermal differentiation and inhibits proliferation.

A comparison of the reliability of self-reported drug use and sexual behaviors using computer-assisted versus face-to-face interviewing

The purpose of this study was to assess the reliability of responses to HIV risk behavior questions obtained using a voice-enhanced, computer-administered self-interview (audio-CASI) system with touch-screen response compared with those obtained via face-to-face interviews administered by trained and experienced interviewers. Additionally, the study assessed bias that may be attributable to an audio-CASI data collection format. The design of the study was a four-group crossover design with random assignment to one of four study conditions: (a) audio-CASI interview at both intake and retest, (b) face-to-face interview at both intake and retest, (c) audio-CASI interview at intake and face-to-face interview at retest, and (d) face-to-face interview at intake and audio-CASI interview at retest. The study was conducted with a sample of drug users at risk for HIV infection interviewed in nonclinical settings. Data were collected at intake and 48 hours after intake. Analyses show that data obtained using voice-enhanced computer interviewing with touch-screen response are reliable and are comparable to data obtained using interviewer administered face-to-face interviews. However, bias was found to be associated with data collection format and may be partially attributable to the complexity of the questionnaire.

A discordance of the cytochrome P450 2C19 genotype and phenotype in patients with advanced cancer

AIMS

To examine the relationship between cytochrome P450 2C19 (CYP2C19) genotype and expressed metabolic activity in 16 patients with advanced metastatic cancer.

METHODS

Individual CYP2C19 genotypes were determined by PCR-based amplification, followed by restriction fragment length analysis, and compared with observed CYP2C19 metabolic activity, as determined using the log hydroxylation index of omeprazole.

RESULTS

All 16 patients had an extensive metabolizer genotype. However, based on the antimode in a distribution of log omeprazole hydroxylation indices from healthy volunteers, four of the patients had a poor metabolizer phenotype and there was a general shift of the remaining 12 patients towards a slower metabolic phenotype. This suggests a reduction in metabolic activity for all patients relative to healthy volunteers. A careful analysis of patient medical records failed to reveal any drug interactions or other source for the observed discordance between genotype and phenotype.

CONCLUSIONS

There are no previous reports of a 'discordance' between genotype and expressed enzyme activity in cancer patients. Such a decrease in enzyme activity could have an impact on the efficacy and toxicity of chemotherapeutic agents and other drugs, used in standard oncology practice.

Farnesol stimulates differentiation in epidermal keratinocytes via PPARalpha

The isoprenoids farnesol and juvenile hormone III (JH), metabolites of the cholesterol biosynthetic pathway, have been shown to stimulate fetal epidermal development in rodents. In this study we determined whether this effect might be attributed to a direct induction of keratinocytes differentiation and examined the mechanisms responsible for these effects. Rates of cornified envelope formation, a marker of keratinocyte terminal differentiation, as well as protein and mRNA levels of two proteins required for cornified envelope formation, involucrin (INV) and transglutaminase, increased 2- to 3-fold in normal human keratinocytes (NHK) treated with either farnesol or JH, even at low calcium concentrations (0.03 mM), which otherwise inhibit differentiation. In contrast, neither cholesterol nor mevalonate affected INV or transglutaminase mRNA levels. Effects of farnesol and JH on INV and transglutaminase mRNA levels were additive with high calcium concentrations (1.2 mM) that independently stimulate keratinocyte differentiation. In contrast, keratinocyte DNA synthesis was inhibited by these compounds. Both farnesol and JH stimulated INV and transglutaminase promoter activity, suggesting regulation at the transcriptional level. A series of truncation and deletion experiments revealed a farnesol-responsive region (-2452 to -1880 base pairs (bp)) in the INV gene. This region contained an AP-1 site. A single base pair mutation of the AP-1 site at -2116 to -2110 bp abolished farnesol responsiveness, identical to effects by peroxisome proliferator-activated receptor (PPARalpha) activators. Farnesoid X-activated receptor mRNA was not detected in NHK, but farnesol treatment increased activities of both a PPAR response element and PPARalpha mRNA levels in NHK. Furthermore, the increase in PPRE activity by farnesol was dependent upon PPARalpha in CV-1 cells. Finally, topical applications of farnesol increased mRNA and protein levels of the differentiation-specific genes, profilaggrin and loricrin, determined by immunohistochemistry and in situ hybridization, in wild-type but not in PPARalpha-/- murine epidermis. These findings suggest a novel role for selected isoprenoid cholesterol intermediates in the regulation of differentiation-specific gene transcription and a convergence of PPARalpha with the cholesterol synthetic pathway.