Polygenic risk score associates with atherosclerosis severity at autopsy

Background

Polygenic risk scores (PRS) for coronary artery disease (CAD) are emerging as a potential method to improve cardiovascular risk prediction. Questions remain about their applicability to diverse populations as well as their correlation with coronary histopathology.

Purpose

To assess whether high genetic risk associates with histopathologic coronary plaque morphology.

Methods

We assessed 122 known CAD risk loci in 954 Black and White subjects within our sudden death registry to generate a PRS. The cohort was divided into quintiles according to z-score-standardized PRS, both in a race-stratified fashion and in the pooled sample. Detailed histopathologic examination of the coronary arteries was performed in all subjects.

Results

Subjects in the highest PRS quintile exhibited more severe atherosclerosis compared to subjects in the lowest quintile, with greater mean cross-sectional luminal narrowing (71.5% (95% CI, 66.6%-76.5%) vs. 56.6% (95% CI, 51.1%-62.1%); adjusted p<0.001; Figure 1) and a higher frequency of calcification (adjusted OR 2.19; 95% CI 1.31–3.68; p=0.003) after adjustment for the first 10 principal components, age, sex, and race. Higher z-score-standardized PRS was predictive for the finding of severe atherosclerosis (i.e., ≥75% cross-sectional luminal narrowing) even after additional controlling for traditional CAD risk factors including hypertension, smoking, diabetes mellitus, and hyperlipidemia (adjusted OR 1.39; 95% CI 1.19–1.63; p<0.001; Figure 2). Among Black subjects, higher PRS was associated with higher odds of plaque rupture (adjusted OR 1.31; 95% CI 1.03–1.66; p=0.03) and predicted CAD-associated cause of death among subjects younger than 50 years old (adjusted OR 1.26; 95% CI 1.01–1.58; p=0.04).

Conclusions

This is the first autopsy study investigating associations between PRS and atherosclerotic plaque morphology at a histopathologic level. Our pathological analysis suggests PRS correlates with plaque burden and coronary artery calcification and may be useful as a method for CAD risk stratification, especially in younger subjects.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): R01 HL141425 Leducq Foundation Grant

Comparison of perometry-based volumetric arm measurements and bioimpedance spectroscopy for early identification of lymphedema in a prospectively-screened cohort of breast cancer patients

Breast cancer-related lymphedema (BCRL) affects more than one in five women treated for breast cancer, and women remain at lifelong risk. Screening for BCRL is recommended by several national and international organizations for women at risk of BCRL, and multiple methods of objective screening measurement exist. The goal of this study was to compare the use of perometry and bioimpedance spectroscopy (BIS) for early identification of BCRL in a cohort of 138 prospectivelyscreened patients. At each screening visit, a patient's relative volume change (RVC) from perometer measurements and change in L-Dex from baseline (ΔL-Dex) using BIS was calculated. There was a negligible correlation between RVC and ΔL-Dex (r=0.195). Multiple thresholds of BCRL were examined: RVC ≥5% and ≥10% as well as and ΔL-Dex ≥6.5 and ≥10. While some patients developed an elevated RVC and ΔL-Dex, many demonstrated elevations in only one threshold category. Moreover, the majority of patients with RVC ≥5%, ΔL-Dex ≥6.5, or ΔL-Dex ≥10 regressed to non-elevated measurements without intervention. These findings suggest a role for combining multiple screening methods for early identification of BCRL; furthermore, BCRL diagnosis must incorporate patient symptoms and clinical evaluation with objective measurements obtained from techniques such as perometry and bioimpedance spectroscopy.

"Prostate cancer is far more hidden…": Perceptions of stigma, social isolation and help-seeking among men with prostate cancer

The purpose of this study was to provide in-depth insight into men's experiences of prostate cancer, specifically: perceived stigma and self-blame, social isolation, unmet need and help-seeking. A qualitative descriptive approach was used. Semi-structured interviews were undertaken with 20 men diagnosed with prostate cancer, and thematic analysis was undertaken. Some participants perceived a stigma associated with prostate cancer and cancer in general, which sometimes acted as a barrier to disclosure. Self-blame and internalisation of cause was not a prominent issue. Participants' descriptions of emotional distress, social isolation and anxiety demonstrated the impact of prostate cancer. Social isolation was most commonly reported as a physical consequence of treatment and/or side effects. Participants felt both support and ongoing care were limited at post-treatment. Most did not seek or receive help for emotional or psychosocial problems from a formal source due to anticipated awkwardness, autonomous coping, not burdening others, unwanted sympathy and retaining privacy. Prostate cancer can cause considerable emotional and social burden for some men, and many are unlikely to seek or receive help. Men, and their support networks, require active encouragement throughout diagnosis, treatment and follow-up to overcome barriers and access additional support, particularly for sexual, emotional and psychosocial issues.

Coronary Artery Disease Associated Transcription Factor TCF21 Regulates Smooth Muscle Precursor Cells that Contribute to the Fibrous Cap

TCF21 is a basic helix-loop-helix transcription factor that has recently been implicated as contributing to susceptibility to coronary heart disease based on genome wide association studies. In order to identify transcriptionally regulated target genes in a major disease relevant cell type, we performed siRNA knockdown of TCF21 in in vitro cultured human coronary artery smooth muscle cells and compared the transcriptome of siTCF21 versus siCONTROL treated cells. The raw (FASTQ) as well as processed (BED) data from 3 technical replicates per treatment has been deposited with Gene Expression Omnibus (GSE44461).

Abstract OT2-5-01: The PREDICT study (prospective, randomized early detection and intervention after breast cancer - Treatment, for women at risk of lymphedema)

Introduction: It is well-documented that lymphedema is one of the most feared long-term side effects of breast cancer (BC) treatment. However, to date, a standardized approach for the quantification and treatment of breast cancer-related lymphedema (BCRL) has yet to be established.

Aims: We propose a screening and intervention trial to assess the efficacy of early detection and intervention with various treatment strategies for BCRL. Intervention comprises the use of compression garments for mild lymphedema and compression garments +/- nighttime bandaging for moderate lymphedema. Other factors to be evaluated include: symptom clusters, treatment adherence, fear avoidance behavior, quality of life (QOL), upper extremity function, and risk factors for BCRL.

Eligibility Criteria: Women 18 years + with a confirmed BC diagnosis, no history of BC, no known metastatic or locally advanced disease, no history of primary lymphedema, sentinel lymph node biopsy or axillary lymph node dissection as part of definitive breast surgery.

Study Design: A two-stage study which includes a Screening and an Intervention trial. The screening trial will evaluate arm volume change during and after BC treatment with target accrual of 8000. Currently, 1286 participants have been enrolled among three sites including MGH, MD Anderson and Brigham and Women's Hospital. Patients will undergo perometer measurements and complete the MGH Lymphedema Evaluation Following Treatment for Breast Cancer (LEFT-BC) survey at each screening assessment to evaluate changes in functionality, upper extremity utilization, fear avoidance behaviors, and QOL. Screening visits will occur pre- and post-operatively, at the conclusion of chemotherapy and/or radiation therapy and every 3-8 months thereafter. Patients will become eligible for intervention trial enrollment if, during the course of screening, unilaterally affected patients develop a relative arm volume change (RVC) of ≥ 5% or bilaterally affected patients develop a weight adjusted change (WAC) of ≥ 5% which persists at a verification measurement within 4-8 weeks. Eligible subjects will be enrolled into one of two groups based on verification RVC/WAC: Group I – Mild Lymphedema (5-10% RVC/WAC) or Group II – Moderate Lymphedema (11-20% RVC/WAC). Subjects are then randomized within each group. Group I subjects are randomized to one of two arms: I-A – Observation, I-B – Compression, and Group II subjects are randomized to one of two arms: II-A – Compression, II-B – Compression + Night Compression Bandaging. Target accrual for the intervention trial is 336 subjects (Group I: 208, Group II: 128).

Clinical Relevance: The results of this study will yield Level I evidence on the effectiveness of early detection and intervention for BCRL. Findings may shape clinical practice in diagnosis and treatment, as well as provide insight regarding the risk factors, symptoms, upper extremity function, and QOL associated with BCRL.*Funding by award #s R01CA139118 &3P5OCA089393, AGT.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT2-5-01.

A novel, validated method to quantify breast cancer-related lymphedema (BCRL) following bilateral breast surgery

We sought to develop a formula to quantify breast cancer-related lymphedema (BCRL) after bilateral breast surgery, which functions independently of the contralateral arm and accounts for fluctuations in patient weight. Perometer arm measurements from 265 unilateral breast surgery patients were analyzed. We assessed the relationship between change in patient weight and contralateral arm volume and developed a weight-adjusted volume change formula (WAC). The WAC formula and previously-established RVC formula were compared for classification of BCRL (> or = 10% volume increase) in unilateral breast surgery patients. We then evaluated BCRL incidence using the WAC formula in 225 bilateral mastectomy patients. Change in patient weight and contralateral arm volume demonstrated an approximately linear relationship. Weight-adjusted arm volume change (WAC) was therefore calculated as WAC = (A2*W1)/(W2*A1) - 1 where A1 is pre-operative and A2 is post-operative arm volume, and W1, W2 are the patient's corresponding weights. In the unilateral analysis, there was no significant difference in number of patients classified as having BCRL using the RVC and WAC formulas (p = 0.65). In bilateral mastectomy patients 11.1% (25/225) developed BCRL, defined as > or = 10% WAC. Independent risk factors for lymphedema included axillary lymph node dissection (ALND) and higher pre-operative BMI (p<0.05). Use of this weight-adjusted arm volume change formula should be of value for quantification of BCRL after bilateral breast surgery.

Abstract P6-09-04: The Association of Low Level Arm Volume Increases with Lymphedema Symptoms Following Treatment for Breast Cancer

Purpose/Objective: The symptoms associated with breast cancer-related lymphedema are well-documented, and include sensations of heaviness, swelling, and tightness in the upper extremity and trunk. However, the clinical significance of low-level arm volume changes frequently experienced by breast cancer patients is not well understood. We sought to determine the association of low level arm volume changes with patient-reported lymphedema symptoms in women treated for breast cancer.

Methods: 267 patients who underwent surgical treatment for breast cancer from 2010–2012 were identified from a cohort of patients prospectively screened for lymphedema at our institution. Patients were assessed with perometer arm volume measurements and a survey of lymphedema symptoms pre and post operatively, and at 3–7 month intervals thereafter. Inclusion in this analysis was limited to unilaterally affected women with ≥ 3 assessments and ≥ 6 months of post-surgical follow-up. Arm volume changes were quantified as Relative Volume Change (RVC): RVC = (A2*U1)/(U2*A1) − 1, where A1 is pre-operative arm volume and A2 is post-operative arm volume on the affected side, and U1 and U2 are arm volumes on the unaffected side at these time points. Low level arm volume change was defined as a measurement with RVC ≥ 5% &lt;10% at an assessment ≥ 3 months post-operatively. Actuarial univariate and multivariate regression analysis was performed to determine the association of low level arm volume change with patient-reported lymphedema symptoms and clinicopathological characteristics.

Results: Low level arm volume changes occurred in 21.7% (58/267) of patients during the follow-up period at a median of 10.4 months post-operatively. Median post-operative follow-up was 12.4 months and 5 assessments per patient. By actuarial univariate analysis, symptoms of larger arm, shoulder, or neck (p &lt; 0.001), tighter sleeve, sleeve cuff, or ring (p &lt; 0.001), and having undergone axillary lymph node dissection (p = 0.02) or regional lymph node radiation (p = 0.01) were significantly associated with low-level arm volume change. By actuarial multivariate analysis, only symptoms of larger arm, shoulder, or neck (p &lt; 0.0001) were associated with low level arm volume change.

Conclusions: This data suggests that patients may be symptomatic for lymphedema even when experiencing low level arm volume changes. These patients should be followed closely for progression of measured arm volume or heightened lymphedema symptoms suggesting progression of the condition.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-09-04.

Abstract OT3-2-02: The PREDICT Study (Prospective, Randomized Early Detection and Intervention after Breast Cancer-Treatment, for women at risk of lymphedema)

Introduction: It is well-documented that lymphedema is one of the most feared long-term side effects of breast cancer (BC) treatment. However, to date, a standardized approach for the quantification and treatment of breast cancer-related lymphedema (BCRL) has yet to be established.

Aims: We propose a screening and intervention trial that will assess the efficacy of early detection and intervention for BCRL. Intervention comprises the use of compression garments for mild lymphedema and compression garments +/− nighttime bandaging for moderate lymphedema. Other factors to be evaluated include: symptom clusters, treatment adherence, fear avoidance behavior, quality of life (QOL), upper extremity function, and risk factors for BCRL.

Eligibility Criteria: Women 18 years + with a confirmed BC diagnosis, no history of BC, no known metastatic or locally advanced disease, no history of primary lymphedema, sentinel lymph node biopsy or axillary lymph node dissection as part of definitive breast surgery.

Study Design: A two-stage study which includes a Screening and an Intervention trial. The screening arm will evaluate arm volume change during and after BC treatment with target accrual of 8000. Patients will undergo measurements via perometry and complete the MGH Lymphedema Evaluation Following Treatment for Breast Cancer (LEFT-BC) Survey at each screening appointment to evaluate changes in functionality, upper extremity utilization (fear associated avoidance), and QOL. Screening visits will occur pre- and post - operatively, at the conclusion of chemotherapy and radiation therapy and every 3–7 months thereafter. Patients will become eligible for enrollment into the intervention trial if, during the course of screening, they develop a relative arm volume change (RVC) of ≥ 5% which persists at a verification measurement within 4–8 weeks. Eligible subjects are enrolled into one of two groups based on verification RVC: Group I – Mild Lymphedema (5–10% RVC) or Group II – Moderate Lymphedema (11–20% RVC). Subjects are then randomized within each group. Group I subjects are randomized to one of two arms: I-A – Observation, I-B – Compression, and Group II subjects are randomized to one of two arms: II-A – Compression, II-B – Compression + Night Compression Bandaging. Target accrual for the intervention trial is 336 subjects (Group I: 208, Group II: 128).

Clinical Relevance: The results of this study will yield level I evidence on the effectiveness of early detection and intervention for BCRL. Findings may shape clinical practice in diagnosis and treatment, as well as provide insight regarding the risk factors, symptoms, upper extremity function, and quality of life (QOL) associated with BCRL.

*Funding by awards R01CA139118 & 3P5OCA089393, AGT

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr OT3-2-02.

Expression of nogo-a is decreased with increasing gestational age in the human fetal brain

Nogo is a member of the reticulon family. Our understanding of the physiological functions of the Nogo-A protein has grown over the last few years, and this molecule is now recognized as one of the most important axonal regrowth inhibitors present in central nervous system (CNS) myelin. Nogo-A plays other important roles in nervous system development, epilepsy, vascular physiology, muscle pathology, stroke, inflammation, and CNS tumors. Since the exact role of Nogo-A protein in human brain development is still poorly understood, we studied its cellular and regional distribution by immunohistochemistry in the frontal lobe of 30 human fetal brains. Nogo-A was expressed in the following cortical zones: ependyma, ventricular zone, subventricular zone, intermediate zone, subplate, cortical plate, and marginal zone. The number of positive cells decreased significantly with increasing gestational age in the subplate and marginal zone. Using different antibodies, changes in isoform expression and dimerization states could be shown between various cortical zones. The results demonstrate a significant change in the expression of Nogo-A during the development of the human brain. The effects of its time- and region-specific regulation have to be further studied in detail.

P4-14-01: Weight-Adjusted Change of Unilateral Arm Volumes for Quantification of Lymphedema after Bilateral Breast Surgery

Background: Accurate quantification of breast cancer-related lymphedema (BCRL) is important for early detection and successful management. Arm volume changes after unilateral breast surgery can be calculated through relative volume change (RVC) of the affected arm using the contralateral arm as a control (Ancukiewicz et al Int J Radiat Oncol Biol Phys 79(5):1436–43 2011). However there currently exists no accurate method for quantifying arm volume changes in patients after bilateral breast surgery. As the number of women undergoing bilateral mastectomies continues to increase, it is critical to develop a method to quantify arm volume changes in this population for detection of lymphedema. Our aim was to develop a weight-adjusted formula for unilateral arm volume changes independent of the contralateral arm for application in the setting of bilateral breast surgery.

Materials and Methods: We analyzed longitudinal measurements of arm volumes in 141 unilaterally affected patients undergoing screening for BCRL with a perometer at our institution (71 with left affected and 70 with right affected arms). Each patient had a baseline measurement prior to surgery and at least one post-surgical measurement. Median time of follow-up was 27.5 months and median standard deviation of longitudinal weight changes within patients during follow-up was 3%.

Results: Unilateral arm volume changes of the unaffected arm were correlated with weight changes at the last follow-up point (Kendall's tau=.58 and P&lt;.0001). Estimates of slope and intercept for median regression line between percent weight change and percent arm volume change evaluated for the unaffected arm at last follow-up are, respectively, .90 [95% CI] and .009 [95% CI]. Thus, percent weight change and percent arm volume change in the unaffected arm have an approximately linear relationship, such that the weight adjusted change (WAC) of affected unilateral arm volumes can be calculated according to the formula WAC=(A2*W1)/(W2*A1) — 1, where A1 is pre-surgical baseline arm volume on the affected side and A2 is post-surgical arm volume on the affected side, and W1, W2 are the patient's weights at these time points. Weight-adjusted change showed a strong correlation with RVC (RVC=(A2*U1)/(U2*A1) — 1), where A1, A2 are arm volumes on the side of the affected breast, and U1, U2 are volumes on the contralateral side at these time points (Kendall's tau=.41, P&lt;.0001).

Discussion: Unilateral arm volume changes can be quantified by adjusting for weight changes. We propose the weight-adjusted change (WAC) formula to calculate unilateral arm volume changes for detection and monitoring of BCRL in patients who undergo bilateral breast surgery. The validity of such a formula needs to be assessed in conjunction with clinically reported lymphedema.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-14-01.

P5-17-03: The Association between Breast Cancer Related Lymphedema's Risk Factors and Likelihood of Edema Progression

Purpose/Objective(s): Breast cancer related lymphedema (BCRL) is one of the most feared long term side effects of treatment. Although emergence of the sentinel lymph node biopsy (SLNB) has decreased the rate of BCRL, it continues to be an issue for this population. The goal of this study is to evaluate the prognostic risk factors for BCRL development and progression based on longitudinal prospective limb volume (LV) measurements and associated surgical, radiation and medical oncology factors.

Materials/Methods: Since 2005 newly diagnosed breast cancer (BC) patients were prospectively screen via perometery (Pero-System). For this analysis patients were required to have undergone at least four measurements and have at least 24 months of follow up to allow for adequate time for LE development. Bilateral pre-operative volume measurements of the upper extremity were compared to postoperative measurements and at 4 to 6 month intervals to assess for limb volume changes. At each time point (tx), relative volume change (RVC) of the treated arm was calculated using volume ratios of treated (T) to non-treated (N) side compared to the pre-operative baseline (t1) (RVC=(Ttx/Ntx)/(Tt1/Nt1)-1) as described in Ancukiewicz et al 2010. Our institution utilizes &gt;5% RVC as an indicator of lymphedema. For this analysis, mild lymphedema was classified as a RVC of 5–9.9% and moderate lymphedema was classified as a RVC ≥ 10%. A univariate analysis was performed to identify risk factors and likelihood to LE progression.

Results: In a cohort of 415 women, 14.4 %(60) and 6.7% (28) developed mild and moderate BCRL, respectively. Twenty percent (14) and 75 %(21) of patients in the mild and moderate cohorts, respectively, had a persistent edema that was documented at a least 2 consecutive data points. Eighty percent (56) and 25% (7) of patients that had a documented incidence of an elevated RVC had returned below an RVC&lt;5% and their subsequent visits. Based on Kendall's Tau P-value of &lt;0.0001 persistent edemas were associated with axillary lymph node dissection (ALND), number of lymph nodes removed, axillary fields and dose of radiation.

Conclusion: Breast cancer related lymphedema is a feared long term side effects and negatively impacts the physical and psychological aspects of an individual's life. A condition that is considered manageable but not curable, it is essential providers identify high risk individuals. Establishing a a lymphedema screening program may identify early lymphedema which could be potentially be treated successfully.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-17-03.

Individual and structural vulnerability among female youth who exchange sex for survival

PURPOSE

Because of growing concerns regarding the heightened vulnerabilities and risk of human immunodeficiency virus infection among youth who exchange sex for survival, we investigated individual risk patterns and structural barriers among young (≤24 years) female sex workers (FSWs) in Vancouver, Canada.

METHODS

Between 2005 and 2008, a total of 255 street-based FSWs (≥14 years) were enrolled into a community-based prospective cohort, and were asked to participate in baseline and biannual questionnaires administered through interviews and human immunodeficiency virus screening. We used contingency table analysis to compare individual and structural barrier results obtained at baseline for younger (≤24 years) FSWs with those of the older (>25 years) FSWs. For longitudinal data, we used generalized estimating equations throughout the follow-up period to determine factors associated with being a young FSW in the past 6 months.

RESULTS

In comparison with older FSWs (n = 199), youth (n = 56) were more likely to spend fewer years engaging in sex exchange (median: 6.4 [interquartile range: 4.6-9.1] vs. 19.9 [interquartile range: 10.0-26.8]; p ≤ .001), belong to an aboriginal ancestry (59% vs. 44%; p = .052), and be homeless (68% vs. 36%; p ≤ .001). In the multivariate generalized estimating equations analysis, youth reported a significantly elevated proportional odds of being homeless (odds ratio [OR]: 1.26 [confidence interval {CI}: 1.08-1.48]), servicing clients in public places (OR: 1.28 [CI: 1.04-1.57]), injecting heroin on a daily basis (OR: 1.35 [CI: 1.06-1.74]), and a significantly reduced odds of accessing methadone maintenance therapy (OR: .76 [CI: .62-.93]).

CONCLUSIONS

This study demonstrates significant displacement of youth who engage in sex exchange to marginalized working and living spaces. The findings of this study bring to attention the critical need for targeted structural interventions including access to youth and gender-specific social housing, safe working spaces, reduction in the amount of harm caused to them, and addiction treatment services for youth engaged in survival sex work.

Impact on the Australian Quitline of new graphic cigarette pack warnings including the Quitline number

Background:

In March 2006, Australia introduced graphic pictorial warnings on cigarette packets. For the first time, packs include the Quitline number.

Objective:

To measure the combined effect of graphic cigarette pack warnings and printing the Quitline number on packs on calls to the Australian Quitline service.

Methods:

Calls to the Australian Quitline were monitored over 4 years, 2 years before and after the new packets were introduced.

Results:

There were twice as many calls to the Quitline in 2006 (the year of introduction), as there were in each of the preceding 2 years. The observed increase in calls exceeds that explained by the accompanying television advertising alone. While call volume tapered back in 2007, it remained at a level higher than before the introduction of new packets. No change was observed in the proportion of first time callers.

Conclusion:

Introducing graphic cigarette packet warnings and the Quitline number on cigarette packets boosts demand for Quitline services, with likely flow on effects to cessation.

Using a quitline plus low-cost nicotine replacement therapy to help disadvantaged smokers to quit

Objectives:

To trial an intervention in a real-life setting to motivate low-income smokers to try to quit. The intervention under trial was the addition of subsidised nicotine replacement therapy (NRT) to a standard population quitline service.

Design:

Participants were low-income smokers, recruited “cold” via either a letter in the mail or a flyer inserted in a local newspaper. The intervention group received the usual service of multisession counselling from the quitline plus access to heavily subsidised NRT. A comparison group received the usual quitline service only. Participants were followed up at 3, 6, and 12 months. Trial participants were also compared with a sample of general callers to the quitline.

Results:

The offer of subsidised NRT recruited more than twice as many low-income smokers than the offer of the cessation service alone (intervention group n = 1000; comparison group n = 377). 63% were first-time callers to the quitline. Intervention respondents showed higher levels of nicotine dependence than comparison group respondents. Comparisons of quitting data were confounded by the differences in the respondents at baseline. 73.5% of smokers in the intervention group tried to quit compared to 61.0% in the comparison group. Unadjusted quit rates were higher in the intervention group than in the comparison group at 3 months and 6 months but not at 12 months.

Conclusions:

Disadvantaged smokers were easily engaged to call the quitline, particularly when offered subsidised NRT. Disadvantaged smokers using the quitline, with and without subsidised NRT, achieved cessation outcomes comparable to other studies of “mainstream” smokers.

Quality control for microarray analysis of human brain samples: The impact of postmortem factors, RNA characteristics, and histopathology

The quality of results from microarray studies depends on RNA quality, which can be significantly influenced by postmortem factors. The aim of this study was to determine which postmortem factors and/or RNA electropherogram characteristics best correspond to microarray output and can be used to prospectively screen RNA prior to microarray analysis. Total RNA was extracted (N=125) from gray and white matter of postmortem frontal and occipital lobe tissue, acquired from normal controls, and patients with schizophrenia, bipolar disorder or major depression. Electropherograms were generated by the Agilent BioAnalyzer 2100, allowing calculation of the 28S/18S ratio, the 18S/baseline peak ratio and the RNA Integrity Number (RIN). These values were compared to post-hybridization image analysis of Affymetrix microarrays. The postmortem variables correlated with some quality measures but could not be used as effective screening tools. Logistic regression demonstrated that all three electropherogram measures were predictive for microarray quality, and that the RIN threshold predictive of "good quality" (>35% present calls) was most consistent with that of prior studies. The optimal RIN must be determined by the investigator's specifications for false inclusion and false exclusion. In contrast to RIN, the quality threshold for the 28S/18S ratio has proven unacceptably variable, due to sensitivity to slight differences in protocol and/or tissue source. In conclusion, the measures we found useful as screening criteria do not replace the need to exclude samples after a microarray analysis is performed, as an acceptable percent call rate and other measures of microarray quality represent the desired endpoint.

Inadequacies in antiretroviral therapy use among Aboriginal and other Canadian populations

We undertook this study to provide a profile of Aboriginal people initiating antiretroviral therapy and their response to treatment. Aboriginal peoples were identified through self-report. Baseline socio-demographics and risk factors were compared between Aboriginal and non-Aboriginal participants as were baseline factors associated with two consecutive plasma viral load measures below 500 copies/ml using contingency table analysis. Multivariate survival analysis of the prognostic factors associated with time to two consecutive plasma viral load measures below 500 copies/ml among eligible participants was undertaken to characterize response to antiretroviral therapy. There were 892 participants with available data for this analysis, of those 146 (16%) self-identified as Aboriginal. Aboriginal participants were more likely to be female (p < or = 0.001), have lower baseline plasma viral loads (p = 0.010), be co-infected with HCV (p < 0.001), live in unstable housing (p < or = 0.001), and report an income of >10K CDN (p < or = 0.001) per annum. Aboriginal people were less likely to report men who have sex with men (p < or = 0.001) and more likely to report injection drug use (p < or = 0.001) as a risk factor for HIV infection. Aboriginal participants were more likely to receive double versus triple combination antiretroviral therapy (p = 0.002), be less adherent in the first year on therapy (p = 0.001) and to have a physician less experienced with treating HIV (p < or = 0.001). When these factors were controlled for, Aboriginal people treated with triple combination therapy were as likely to respond and suppress their viral load below 500 copies. In the era of HAART, our results indicate that Aboriginal people living with HIV/AIDS were less likely to receive optimal therapy. However, when Aboriginals did receive triple drug therapy they suppressed just as well as non-Aboriginals.

Effect of H-7 and Lat-B on retinal physiology

PURPOSE

To investigate the effects of H-7 and Latrunculin B (Lat-B) on retinal vascular permeability and electrophysiology at concentrations that increase outflow facility in monkeys.

METHODS

One eye of 1 rhesus and 22 cynomolgus monkeys received an intravitreal bolus injection of H-7 or Lat-B; the opposite eye received vehicle. Multifocal electroretinograms (mfERGs), and photopic and scotopic full-field electroretinograms (ffERGs, sERGs) were recorded in subsets of monkeys at baseline and at multiple time-points post-H-7 or Lat-B. Vitreous fluorophotometry (VF) and fluorescein angiography (FA) were also performed.

RESULTS

No differences between the H-7 or Lat-B treated and control eyes were found in ffERGs, mfERGs, sERGs, or in FAs in any monkey. No significant difference was found in vitreous fluorescein levels between H-7 treated or Lat-B treated vs. control eyes.

CONCLUSIONS

No effect on retinal vascular permeability or retinal electrophysiology was apparent after intravitreal administration of H-7 or Lat-B at doses that increase outflow facility and lower IOP when given intracamerally.

Uptake and effectiveness of the Australian telephone Quitline service in the context of a mass media campaign

OBJECTIVES

Since June 1997, Australia has run its first nationally coordinated mass media anti-smoking campaign, with all States collaborating to offer a standard Quitline service. An overview of the Australian national Quitline service is presented as well as two studies describing (a) the relationship between television advertising and call volume and type, and (b) the quit rates of callers over time.

DESIGN

Data on extent of advertising, as measured by weekly television target audience rating points (TARPs), is compared with weekly call volume and disposition. A randomly selected sample of callers was followed up at 3 weeks, 6 months and 12 months to assess caller appraisal and quit rates.

SETTING

The Australian Quitline service, in the context of a nationally coordinated, major anti tobacco campaign.

RESULTS

In a one year period from June 1997, 3.6% of adult Australian smokers called the Quitline. Weekly call volume was strongly related to TARPs and increased further when an advertisement specifically promoting the Quitline was broadcast. Calls involving requests for counselling, as opposed to brief calls to request quit materials, were more likely with lower TARPs. Of the cohort who were smoking at baseline, 28% reported they had quit smoking at a one year follow up and 5% had been quit for an entire year.

CONCLUSIONS

In the context of a national mass media campaign, this study illustrates that it is possible to bring together differing State based services to provide an accessible, acceptable, and effective quit smoking service.

The NS2 protein generated by the parvovirus minute virus of mice is degraded by the proteasome in a manner independent of ubiquitin chain elongation or activation

The NS2 protein generated by the parvovirus minute virus of mice is very labile, having a half-life during infection of approximately 90 min. The degradation of NS2 is blocked by proteasome inhibitors but is likely ubiquitin independent: NS2 does not form detectable higher molecular weight ubiquitin-containing conjugates, and NS2 degradation requires neither ubiquitin chain elongation nor intracellular ubiquitin activation. We have also identified a region in the carboxyl half of NS2 that is required for its proteasome-mediated degradation.

Cue sensitivity in women with cardiac disease

The purpose of this study was to discover factors that influenced the healthcare seeking behavior of women cardiac patients. Interviews included 10 women with cardiac disease, two women at risk for cardiac disease, three advanced nurse practitioners, and one cardiologist. Participants were interviewed on two occasions. Taped transcripts were reviewed using a grounded theory approach. Analysis revealed a core process of cardiac cue sensitivity that originated in the period prior to entry into the healthcare system. The stages of this process included: cue apprehension, cue assimilation, and medical consultation. Cues were signs, symptoms, or self risk appraisal. Decisions to discount or attend to cues was dependent on the nature, intensity, and specificity of the cue to cardiac disease as well as the woman's knowledge and experience with cardiac disease and validation with others. A sensitivity to the subjective cue experiences of women and a recognition of public attitudes regarding women and cardiac disease facilitates their entry into the healthcare system and improves outcomes for women with cardiac disease.

Distinct role of gp130 activation in promoting self-renewal divisions by mitogenically stimulated murine hematopoietic stem cells

Previous studies have demonstrated hematopoietic stem cell amplification in vitro after the activation of three cell-surface receptors: flt3/flk2, c-kit, and gp130. We now show flt3-ligand and Steel factor alone will stimulate >85% of c-kit(+)Sca-1(+)lin(-) adult mouse bone marrow cells to proliferate in single-cell serum-free cultures, but concomitant retention of their stem cell activity requires additional exposure to a ligand that will activate gp130. Moreover, this response is restricted to a narrow range of gp130-activating ligand concentrations, above and below which hematopoietic stem cell activity is lost. These findings indicate a unique contribution of gp130 signaling to the maintenance of hematopoietic stem cell function when these cells are stimulated to divide with additional differential effects dictated by the intensity of gp130 activation.

Successful treatment of oral squamous cell carcinoma with intralesional fluorouracil in a Malayan tapir (Tapirus indicus)

An oral mass was observed in a Malayan tapir (Tapirus indicus). Squamous cell carcinoma was diagnosed by histologic examination of a biopsy specimen. A series of intralesional injections using fluorouracil resulted in complete regression of the neoplasm with no recognized adverse effects.

Hippocampal auditory gating in the hyperactive mocha mouse

The mouse mutants mocha (mh) and mocha2J (mh2J) result from separate mutations in the same gene (AP-3 delta) that arose independently on different backgrounds of inbred strains. They exhibit a neurological phenotype that includes hyperactivity, an epileptiform EEG and changes in the basic function of the hippocampus. Depth electrode recordings of hippocampal auditory evoked potentials revealed that the response to the first of two paired tones was significantly enhanced in mocha and mocha2J, as compared with littermate controls. The pronounced theta rhythm characteristic of unanesthetized mocha mice was not observed in these chloral-hydrate anesthetized mice, whereas spike discharge activity was frequently present in the recordings.

Chronic hypertension with subsequent congestive heart failure in a western lowland gorilla (Gorilla gorilla gorilla)

Chronic severe subclinical systemic hypertension was diagnosed in a 28-yr-old male western lowland gorilla (Gorilla gorilla gorilla). Thoracic radiography, electrocardiography, and echocardiography revealed an enlarged heart with a hypertrophied left ventricle, mitral regurgitation, and a persistent left bundle branch block. Enalapril, later combined with nifedipine, was of some value in reducing the hypertension, with partial reversal of cardiac enlargement and resolution of the bundle branch block. Two years after initiation of treatment, the gorilla developed lethargy and dyspnea. The diagnosis of heart failure was confirmed under anesthesia; the gorilla did not recover and was euthanized. Postmortem examination confirmed congestive heart failure with chronic, fibrosing cardiomyopathy similar to that in other gorillas.

Purification of hematopoietic stem cells for further biological study

For many years, the hematopoietic system has provided a convenient and fascinating model for studies of the molecular processes regulating cell growth and differentiation. However, this system also poses considerable challenges because the most primitive "stem" cells as well as their initial differentiating progeny are normally present in hematopoietic tissues at extremely low frequencies and no unique, stable phenotype has yet been identified to allow hematopoietic cells with specific stem and progenitor functions to be measured directly. Rather, this requires the use of functional assays that detect their developmental properties and take several weeks to complete. Accordingly, many investigations of primitive hematopoietic cell behavior and their responses to molecular cues in the environment have relied on the development of cell separation techniques specifically designed for obtaining highly enriched populations of primitive hematopoietic cells. Key to these procedures is the use of a preenrichment step(s) in which differences in cell density, size, or sensitivity to pharmacological agents or surface phenotype are exploited to first "debulk" the sample. This step can then be followed by a more selective antibody-mediated procedure to generate useful numbers of highly purified cells. Batchwise immunoadsorption techniques offer many advantages for obtaining enriched populations of hematopoietic progenitors because they avoid the nonspecific toxicity seen with antibody-mediated cell killing and are suitable for rapidly processing large samples. For any cell separation procedure, a balance must be struck between the purity and the recovery of the desired cells because steps to increase cell purity usually reduce yields. Both the negative and the positive selection techniques are useful strategies but negative selection usually requires one less manipulation step and circumvents potential effects incurred by the presence of antibody on the surface of the cell being isolated. Specific details for the use and results obtained with an immunomagnetic negative column selection technique are then presented.

Antisense expression of the human pro-melanin-concentrating hormone genes

Expression of transcripts for human pro-melanin concentrating hormone (pMCH) were studied in the hypothalamus, the primary location for pMCH producing cells in the mammalian CNS. Human hypothalamic tissue was extracted for total RNA and the cDNA generated with reverse transcriptase (RT). PCR amplification with primers spanning exons 2 and 3 of the pMCH human-variant genes (pMCHL), yielded an unspliced product, confirming prior work [T.B. Campbell, C.K. McDonald, M. Hagen, The effect of structure in a long target RNA on ribozyme cleavage efficiency, Nucleic Acids Res. 25 (1997) 4985-4993]. In addition, this product was shown to be exclusively antisense, and to be derived from the 5p (pMCHL1), not the 5q (pMCHL2) locus. Thus, there is no evidence that the MCH peptide-precursor molecule is produced in the brain by the human-variant pMCHL loci. In contrast, corresponding RT-PCR for pMCH RNA generated by the locus on 12q, demonstrated the presence of both sense and antisense spliced RNA. Partial sequencing of the spliced product confirmed that production of at least the two C-terminal peptides would occur from the 12q pMCH locus. The significance of the findings for pMCH and pMCHL1 are discussed relative to what is known about the function of endogenous antisense RNA.

Radiation hybrid mapping of the two highly homologous human-variant pMCHL genes by PCR-SSCP

When gene loci are very similar in sequence, as in gene families or multiple pseudogenes, it is difficult to determine the specific location of the individual genes. We show here that applying PCR-SSCP to a radiation hybrid panel allowed mapping and specific sequencing of two genes with only a few sequence differences. Human-variant forms of the promelanin-concentrating hormone (pMCH) gene are found in two locations in the genome, previously localized by FISH to 5p14 and 5q12-q13. Without prior knowledge of sequence variation between the loci, we observed a difference in migration pattern in PCR-SSCP, indicating the presence of at least one point of sequence divergence. PCR-SSCP of 93 samples from a human-hamster radiation hybrid panel revealed the location of the genes to be between markers WI-4804 and AFM225YC5 on chromosome 5p, and between markers WI-3133 and WI-4225 on chromosome 5q. Sequencing of the two 680-bp PCR products from the hybrid panel demonstrated 3 bases of sequence difference between the 5p and 5q locations.

Both T-helper-1- and T-helper-2-type lymphokines are depressed in posttrauma anergy

BACKGROUND

We have previously shown that an intrinsic postinjury T-cell dysfunction defined as lack of proliferative response to direct stimulation through the T-cell receptor, referred to here as "anergy," occurs in a subgroup of patients with severe trauma and is associated with organ failure. It has been suggested recently that a dominance of T-helper-2 (Th2) lymphokine production might be responsible for immunosuppression and associated with poor patient outcome. Here, we hypothesize that anergy is associated with global failure of T lymphokine (T LK) production, suggesting that poor outcome is not the result of an excess of immunosuppressive T LK (i.e., interleukin (IL)-10) but rather results from lost T-cell regulatory networking.

METHODS

Purified T cells from 37 severely injured trauma patients were cultured and stimulated with alphaCD3/alphaCD4, and proliferation was assessed at 72 hours. Anergy is defined as occurring when the patient's T-cell proliferation to alphaCD3/alphaCD4 is less than 50% of the simultaneously run normal proliferation. Culture supernatants were assessed for T LK production by enzyme-linked immunosorbent assay. Clinical severity was measured by the multiple organ dysfunction syndrome (MODS) and Acute Physiology and Chronic Health Evaluation III scores.

RESULTS

Anergy occurred in 20 of 37 patients, and it usually appeared at greater than 5 to 7 days after injury. There was a global reduction of T LK production during T-cell anergy (IL-2, 2.5%; interferon (IFN)gamma, 30.5%; IL-4, 11.8%; and IL-10, 16.9%) compared with increased or unchanged T LK production during the nonanergic state (IL-2, 83%; IFNgamma, 230%; IL-4, 110%; and IL-10, 307.9%; p < 0.01). There was a significant direct correlation between depressed IL-4 and depressed IFNgamma (r = 0.620, p < 0.001), indicating a diminished LK production of both types of T-helper cells (Th1 and Th2). Decreased IL-2 and IL-10 levels were also specifically correlated to each other during the anergic state (r = 0.91, p < 0.001). The average MODS score for patients during anergy was significantly higher (7.6) than their MODS score in the absence of anergy (4.0, p = 0.01). When IL-2 and IL-10 were measured simultaneously, a predominance of Th2 LK (IL-10) production would result in an IL-10/IL-2 ratio greater than 1. We found, however, that this ratio was not greater than 1 in 80% of assays in which T cells were anergic (p = 0.01).

CONCLUSION

During T-cell anergy there is not a predominance of Th2 lymphokine production but rather a global depression of the T-cell lymphokine profile. Both depressed T-cell proliferation and depressed LK production correlate to poor clinical outcome.

Expansion in vitro of adult murine hematopoietic stem cells with transplantable lympho-myeloid reconstituting ability

Elucidation of mechanisms that regulate hematopoietic stem cell self-renewal and differentiation would be facilitated by the identification of defined culture conditions that allow these cells to be amplified. We now demonstrate a significant net increase (3-fold, P < 0.001) in vitro of cells that are individually able to permanently and competitively reconstitute the lymphoid and myeloid systems of syngeneic recipient mice when Sca-1(+)lin- adult marrow cells are incubated for 10 days in serum-free medium with interleukin 11, flt3-ligand, and Steel factor. Moreover, the culture-derived repopulating cells continued to expand their numbers in the primary hosts at the same rate seen in recipients of noncultured stem cells. In the expansion cultures, long-term culture-initiating cells increased 7- +/- 2-fold, myeloid colony-forming cells increased 140- +/- 36-fold, and total nucleated cells increased 230- +/- 62-fold. Twenty-seven of 100 cultures initiated with 15 Sca-1(+)lin- marrow cells were found to contain transplantable stem cells 10 days later. This frequency of positive cultures is the same as the frequency of transplantable stem cells in the original input suspension, suggesting that most had undergone at least one self-renewal division in vitro. No expansion of stem cells was seen when Sca-1+TER119- CD34+ day 14.5 fetal liver cells were cultured under the same conditions. These findings set the stage for further investigations of the mechanisms by which cytokine stimulation may elicit different outcomes in mitotically activated hematopoietic stem cells during ontogeny and in the adult.

Optimizing the metal binding parameters of an EF-hand-like calcium chelation loop: coordinating side chains play a more important tuning role than chelation loop flexibility

In calcium signaling pathways regulated by the EF-hand Ca2+ binding motif, proper regulation requires that the equilibrium and kinetics of Ca2+ binding to the EF-hand chelation loop be precisely optimized for each physiological application. Studies of small-molecule organic chelators have shown that metal binding parameters can be tuned both by the nature of the coordinating ligands and by the structural framework to which these ligands are attached. By analogy, the present study tests the relative importance of (i) coordinating side chains and (ii) backbone torsion angle constraints to the tuning of an EF-hand-like Ca2+ chelation loop. A series of engineered chelation loops are generated by modifying Ca2+ binding site of the Escherichia coli galactose binding protein. The resulting loops, each containing an altered coordinating side chain or a Gly substitution, are compared with respect to their metal binding affinities, specificities, and dissociation kinetics. The Gly variants examined include substitutions which eliminate or introduce a Gly at each of the nine chelation loop positions. The results reveal that Gly is not tolerated at loop positions 1, 3, 5, or 8 or at the external coordinating position, where the removal of a key coordinating or hydrophobic side chain destabilizes the protein. In contrast, Gly residues at loop positions 2, 4, 6, and 7, none of which is required for side chain coordination, have little effect on Ca2+ affinity and the ability to discriminate between cations of different size and charge. Kinetic measurements show that some of these Gly residues measurably alter the rates of metal ion association and dissociation, but in each case the two rates are changed by approximately the same factor so that the effects on equilibrium are minor. Overall, Gly residues yield surprisingly small effects at loop positions 2, 4, 6, and 7, especially when compared to the larger equilibrium and kinetic effects observed for coordinating side chain substitutions. It follows that the conserved Gly at position 6 is not required for Ca2+ binding and that constraints on the backbone torsion angles at the non-coordinating side chain positions 2, 4, 6, and 7 play a relatively minor role in tuning metal binding parameters. Instead, specific coordinating side chains optimize the metal binding parameters of the GBP chelation loop for its protein context and biological application.

Differential ability of flt3-ligand, interleukin-11, and Steel factor to support the generation of B cell progenitors and myeloid cells from primitive murine fetal liver cells

A variety of factors produced by stromal fibroblasts, including Flt3-ligand (FL), interleukin-11 (IL-11), Steel factor (SF), and IL-7, have been implicated in stimulating the production of pre-B cells and myeloid cells from primitive hematopoietic precursors. To investigate their relative roles in this process, either as single-acting or synergistic agents, we compared the yield and types of cells produced after 2 weeks from small numbers of Sca-1+ Lin- (i.e., B220-, Ly-1-, Gr-1-, and Ter-119-) day 14.5 murine fetal liver cells placed in stromal cell-free cultures containing all possible combinations of FL, SF, IL-7, and IL-11. None of these factors alone supported the production (or survival) of any cells beyond 1 week: only pairs of factors consisting of either FL or SF plus either IL-11 or IL-7 were effective in this regard, with FL plus IL-11 being the most potent pair (approximately 7 x 10(4) cells obtained per 100 Sca-1+ Lin- input cells). The maximum numbers of cells were produced in the presence of FL, IL-11, and IL-7: these included both B220+ and Mac-1+/Gr-1+ cells (approximately 10(6) and approximately 2 x 10(5), respectively, per 100 Sca-1+ Lin- input cells). Both of these lineages were also obtained with each of the other possible three-factor combinations, albeit with variable effectiveness. Omission of either FL or IL-7 caused the greatest reduction in the yield of B220+ cells (approximately 130-fold and approximately 80-fold, respectively). Omission of IL-11 and, to a lesser extent, FL caused the greatest reduction in the yield of Mac-1+/Gr-1+ cells (approximately 90-fold and approximately 3-fold, respectively). When fetal calf serum was replaced with a defined serum substitute, the out put of B220+ cells remained the same but myelopoiesis was consistently enhanced (approximately 5- to 20-fold). These findings support a model involving factor redundancy in the extracellular signals required to stimulate the production and amplification of both lymphoid and myeloid cells from early Sca-1+ Lin- cells. They also reveal quantitative differences in the abilities of different competent factor combinations to promote this process, which may be further modulated by the presence of undefined serum components.

Impaired steel factor responsiveness differentially affects the detection and long-term maintenance of fetal liver hematopoietic stem cells in vivo

The results of previous studies have shown that the development of hematopoiesis during fetal life can occur in the absence of Steel factor (SF) signaling. On the other hand, impairment of this mechanism can severely compromise the ability of cells from adult bone marrow to regenerate hematopoiesis on their transplantation into myeloablated recipients. This apparent paradox could result from changes during ontogeny in the responsiveness of hematopoietic stem cells to regulators that may substitute for SF as well as from differences in the availability of such factors during embryogenesis and in the myeloablated adult. To investigate these possibilities, we studied the effect of W41 and W42 mutations on the numbers, phenotype, and posttransplant self-renewal behavior of primitive hematopoietic cells present in the fetal liver (FL) of 14.5-day-old mouse embryos. In W41/ W41 FL, day-12 spleen colony-forming units and long-term culture-initiating cells appeared both quantitatively and qualitatively similar to their counterparts in the FL of +/+ embryos. W41/W41 FL also contained near normal numbers (approximately 50% of controls) of transplantable lymphomyeloid stem cells with competitive reconstituting ability in myeloablated adult +/+ recipients (as assessed for up to at least 16 weeks posttransplant). Moreover, both the original phenotype of these W41/W41 competitive repopulating units (CRUs) and their clonal posttransplant output of mature progeny were normal. Similarly, when myeloablated adult +/+ mice were cotransplanted with 5 x 10(4) +/+ FL cells and a sevenfold to 70-fold excess of W41/W41 FL CRUs, the contribution of the +/+ FL CRUs to the circulating white blood cell count present 5 weeks later was markedly reduced as compared with that of mice that received only +/+ FL cells. However, over the next 3 months, the proportion of mature white blood cells that were derived from +/+ precursors increased significantly (P < .002) in all groups (to > or = 30%), indicating that the ability to sustain hematopoiesis beyond 5 weeks is more SF-dependent than the ability to initially reconstitute both lymphoid and myeloid compartments. Cells from individual FL of W42/+ matings also showed an initial ability (at 7 to 8 weeks posttransplant) to competitively repopulate both lymphoid and myeloid compartments of myeloablated +/+ adult recipients. However, in contrast to recipients of normal or W41/W41 FL cells, the repopulation obtained with the W42 mutant stem cells was transient. Secondary transplants confirmed the inability of the W42 mutant cells to regenerate or even maintain a population of transplantable stem cells. Taken together with previous results from studies of CRUs in adult W mice, these findings support the concept of changes in the way hematopoietic stem cells at different stages of development respond to the stimulatory conditions evoked in the myeloablated recipient. In addition, they provide the first definitive evidence that SF is a limiting physiological regulator of sustained hematopoietic stem cell self-renewal in vivo.

In vivo growth of Epstein-Barr virus transformed B cells with mutations in latent membrane protein 2 (LMP2)

Epstein-Barr virus (EBV) causes infectious mononucleosis in adolescents and is associated with malignant B lymphocyte proliferation in AIDS patients, patients undergoing immune suppression for organ transplantation, and SCID mice. In vitro, EBV transformed, latently infected lymphoblastoid B cell lines (LCLs) contain EBV episomes and express nine virus encoded proteins. Six are nuclear proteins (EBNAs) and three are the integral membrane proteins, LMP1, LMP2A, and LMP2B. To determine if LMP2 was essential for in vivo growth, SCID mice were injected with LCLs containing wild-type EBV (LMP2+) or with LCLs transformed with EBV containing mutations in either LMP2A or LMP2B (LMP2-). SCID mice injected with the LMP2+ or LMP2- LCLs were monitored for tumor development, length of time to tumor development, and phenotypic characterization of the resulting tumors. No difference was observed in any of the above parameters between LMP2+ and LMP2- LCLs demonstrating that LMP2 is not essential for the in vivo growth of EBV transformed B lymphocytes in SCID mice.

Schistosoma mansoni: L-glutamate-induced contractions in isolated muscle fibers; evidence for a glutamate transporter

Schistosoma mansoni muscle fibers contract in response to L-glutamate in a dose-dependent manner (10(-6)-10(-3) M). L-aspartate and D-aspartate are likewise effective in eliciting contraction of the fibers. Mammalian glutamate receptor agonists produce little or no contraction at concentrations as high as 1 mM. In addition, common glutamate receptor antagonists do not inhibit the contraction induced by L-glutamate. However, amino acids known to be substrates for the high-affinity glutamate transporter elicit contraction of the muscle fibers. These results suggests that there is a high-affinity glutamate transporter on the muscle fibers which, because of its electrogenic nature, is causing depolarization and contraction. This is supported by the evidence that contraction induced by L-glutamate is dependent on extracellular Ca2+ and is blocked by nicardipine (10 microM). [3H]L-glutamate is taken up in a dose-dependent manner by the muscle fiber preparation. This uptake is also time- and temperature-dependent. Both the L-glutamate-induced contractile response and [3H]L-glutamate uptake are Na(+)-dependent and can be blocked by specific inhibitors of the high-affinity transporter. This experimental evidence supports the hypothesis that there is a Na(+)-dependent high-affinity glutamate transporter on the schistosome muscle membrane.

EBNA-2 and EBNA-3C extensively and mutually exclusively associate with RBPJkappa in Epstein-Barr virus-transformed B lymphocytes

Although genetic and biochemical data indicate that the cell protein RBPJkappa is a mediator of EBNA-2 and EBNA-3C effects on transcriptional regulatory elements, the extent of association of these Epstein-Barr virus nuclear proteins with RBPJkappa in transformed B lymphocytes has not been determined. We now report that most of the EBNA-2 and at least 20% of the EBNA-3C coimmunoprecipitated with RBPJkappa from extracts of transformed B lymphocytes that contained most of the cellular EBNA-2 and EBNA3C. Both proteins are associated preferentially with the smaller of the two RBPJkappa isoforms. EBNA-2-RBPJkappa complexes do not contain EBNA-3C, and EBNA-3C-RBPJkappa complexes do not contain EBNA-2. Although EBNA-2 and EBNA-3C are extensively associated with RBPJkappa, a fraction of RBPJkappa appears to be free of EBNAs after repeated immunoprecipitations with anti-EBNA, Epstein-Barr virus-immune, human antibody. Promoters with RBPJkappa sites in their regulatory elements are likely to be differentially regulated by these RBPJkappa-EBNA-2 and RBPJkappa-EBNA-3 complexes.

Severity of medical and neurologic complications as a determinant of neurodevelopmental outcome at 6 and 12 months in very low birth weight infants

Very low birth weight (n = 154) and term infants (n = 119) had neurologic and developmental assessment at 6 and 12 months of age. Preterm infants with severe neonatal complications were considered to be at high risk, and those with milder complications were considered to be at low risk, for neurodevelopmental abnormality. Compared to term infants, high- and low-risk infants had abnormalities at 6 months in total neurologic score, cranial nerves, motor tone, motor coordination, and reflexes (P < .001). At 12 months, all groups had improved. However, high-risk infants had persistent abnormalities in the same subcategories (P < .001), whereas low-risk infants differed from term infants only in motor tone (P < .001). Bayley developmental scores were different for all groups at 6 months (P < .001), but at 12 months only high-risk infants differed from term infants (P < .01). These results demonstrate improvement in neurologic and developmental scores over time in very low birth weight infants. The degree of neurodevelopmental abnormality and improvement over time is related to severity of neonatal complications in preterm infants.

The repopulation potential of fetal liver hematopoietic stem cells in mice exceeds that of their liver adult bone marrow counterparts

Varying, limiting numbers of unseparated or purified cells (Ly-5.1), either from 14.5-day-old fetal liver (FL) or from adult bone marrow (BM) were coinjected with 10(5) unseparated BM cells (Ly-5.2) into lethally irradiated adult C57B1/6 recipients (Ly-5.2). The kinetics of donor cell repopulation of the lymphoid and myeloid compartments by Ly-5.1+ donor hematopoietic stem cells (ie, competitive repopulation units [CRU]) were monitored at various time points after the transplantation by Ly-5 analysis of the peripheral white blood cells (WBC). Recipients that had received on average less than 2 adult BM or FL CRU did not show a significant difference in the level of donor-reconstitution when analyzed 4 weeks after the transplantation, However, at 8 and 16 weeks, the FL recipients showed a significantly higher percentage of donor-derived nucleated peripheral blood cells than did the recipients of adult BM cells. Analysis of individual mice showed that approximately 80% of the recipients of FL CRU showed an increase in mature WBC output between 4 and 8 weeks after transplantation, whereas this occurred in less than 40% in the recipients of adult BM cells. In addition to this effect on mature cell output, the cellularity of the reconstituted BM was significantly higher in recipients of FL CRU than in recipients of adult BM CRU, even at 7 to 9 months after transplantation, which is consistent with an increased clonal expansion of FL CRU. When marrow cells from primary recipients of FL CRU were injected into secondary recipients, a significantly higher percentage of these mice showed donor-reconstitution of their lymphoid and myeloid compartments (P < .01) and to a greater extent (P < .008) as compared with mice that had received marrow cells from primary recipients of similar numbers of adult BM CRU. Taken together, these results show that individual FL CRU exhibit a greater proliferative activity in vivo than similar cells from adult BM that is accompanied by a greater production of daughter CRU.

A comparison of long-term repopulating hematopoietic stem cells in fetal liver and adult bone marrow from the mouse

Previous studies have shown that stem cells able to competitively reconstitute the hematopoietic system of lethally irradiated mice (competitive repopulating units [CRU]) can be obtained in highly purified form from adult mouse bone marrow (BM) by the isolation of cells with a Sca-1+Lin-WGA+ phenotype. We now report on the phenotypic characteristics of CRU from day-14.5 murine fetal liver (FL). Our results confirm previous reports of similarities between the two CRU populations but also reveal a few striking differences. Both were found to express the Sca-1 antigen (SCA-1+ and surface molecules that bind wheat germ agglutinin (WGA+), and both show an absence or low expression of a number of markers characteristic of mature hematopoietic cells: B220, Gr-1,ly-1 and Ter119 (together termed Lin*-). Limiting dilution analysis of recipients transplanted with purified Sca-1+Lin*- FL cells with intermediate forward- and side-scatter properties showed that the frequency of CRU in this FL subpopulation was one in 39 cells. This represents an enrichment of approximately 450-fold over the labeled but unseparated FL starting population (one in 17,300 total FL cells). These FL CRU also resembled their counterparts in adult BM in that they expressed high levels of MHC class I and CD43 and intermediate levels of heat-stable antigen (HSA) and c-kit and did not express, or expressed at a low level, Thy-1.2, CD71, and the antigen recognized by the Fall-3 monoclonal antibody (mAb). In contrast, a high percentage of the Sca-1+Lin*- cells isolated from 14.5-day-old FL stained with the AA4.1, anti-Mac-1, and the anti-CD45RB mAbs and retained Rhodamine 123 (Rh123(bright)), whereas the Sca-1+Lin-WGA+ CRU-containing fraction of adult BM cells was found to be AA4.1-, Mac-1-, CD45RB-, and Rh123(dull). These differences in phenotype between CRU in FL and adult BM indicate changes that occur during ontogeny in cells that are similar with respect to their totipotentiality and long-term repopulating potential and complement parallel observations of functional differences between these two populations of CRU.

Studies of W mutant mice provide evidence for alternate mechanisms capable of activating hematopoietic stem cells

Previous studies have suggested that Steel factor (SF) can influence the behavior of many types of hematopoietic progenitor cells both in vivo and in vitro, although whether these may include the most primitive populations of totipotent repopulating cells remains controversial. To approach this question, we measured the number of Sca1+Lin-WGA+ cells, the number of cells with demonstrable myeloid (long-term culture-initiating cell [LTC-IC]) or both myeloid and lymphoid (LTC-IC(ML)) potential in 4- to 5-week-old long-term cultures containing irradiated primary marrow feeder layers, and the number of multilineage long-term in vivo repopulating cells (competitive repopulating unit [CRU]) present in the marrow of W42/+ or W41/W41 mice compared to +/+ controls. There was no significant effect of either of these W mutations on the number of Sca1+Lin-WGA+ cells and, in W41/W41 mice, neither LTC-IC nor LTC-IC(ML) populations appeared to be affected. On the other hand, although W41/W41 and W42/+ cells could both be detected in the in vivo CRU assay, their numbers were markedly reduced (17- and seven-fold, respectively) in spite of the fact that both of these W mutant genotypes contained near normal numbers of day-9 and -12 colony-forming units-spleen (CFU-S). In vitro quantitation of erythroid (burst-forming units-erythroid [BFU-E]), granulopoietic (CFU-granulocyte/macrophage [CFU-GM]), multilineage (CFU-granulocyte/erythrocyte/monocyte/macrophage [CFU-GEMM]), and pre-B clonogenic progenitors (CFU-pre-B) also revealed no differences in the numbers (or proliferative potential) of any of these cells when W41/W41 or W42/+ and normal mice were compared, although day 3 BFU-E from both types of W mutant mice showed no response to the typical enhancing effect exerted by SF on their +/+ counterparts. Taken together, these findings are consistent with the view that SF activation of c-kit receptor-induced signaling events is not a rate-limiting mechanism controlling red blood cell production during normal development until hematopoietic cells differentiate beyond the day-3 BFU-E stage. Nevertheless, normal hematopoietic stem cells do appear to be responsive to SF, since their W mutant counterparts display a disadvantage in the in vivo setting which is exaggerated under conditions of hematopoietic regeneration. On the other hand, alternative mechanisms also appear to contribute to the regulation of hematopoietic stem cell numbers in vivo and to their detection as LTC-IC in vitro.

Regulation of Epstein-Barr virus latency by latent membrane protein 2

Like other herpesviruses, Epstein-Barr virus persists in its host through its ability to establish a latent infection that periodically reactivates. Latent membrane protein 2A (LMP2A) regulates reactivation from latency by interfering with normal B cell signal transduction processes, and may define a new class of regulators of herpesvirus latency.

Neuromuscular physiology and pharmacology of parasitic flatworms

The trematode and cestode flatworms include numerous parasitic forms of major medical and economic importance. A better knowledge of the neuromuscular physiology of these animals could lead to development of new control measures against these parasites. Since these animals are near the stem from which all other animals have evolved, better knowledge of these animals could also yield valuable information about the early evolution of nerve and muscle systems in the animal kingdom. This review focuses on what is known about the characteristics of the somatic muscle in these animals. The anatomy of the muscles is described along with a review of current information about their electrophysiology, including descriptions of the ion channels present. Also included is a summary of recently acquired data concerning the nature of serotonin, peptide, acetylcholine and glutamate receptors on the membranes of the muscles.

Nitric oxide therapy for persistent pulmonary hypertension of the newborn

Nitric oxide has recently been introduced to the world of neonatal pulmonary medicine. The discovery of endogenous nitric oxide production has stimulated extensive research into vascular biology to find the relation of nitric oxide to the transition of circulatory patterns at birth. Persistent pulmonary hypertension of the newborn (PPHN) has long been recognized as a neonatal complication to a variety of disorders. Traditional treatments for PPHN have been associated with adverse effects. Nitric oxide is considered the only selective pulmonary vasodilator to date. Nitric oxide therapy does not produce systemic hypotension, often associated with the use of intravenous vasodilators. This new therapy may possibly reduce or eliminate the need for invasive life-saving procedures such as extracorporeal membrane oxygenation. This article discusses in great detail nitric oxide chemistry and physiology and the procedure for nitric oxide delivery by inhalation and reviews the results of recent research.

Nonlinear effects of radiation dose on donor-cell reconstitution by limited numbers of purified stem cells

Despite the increasing use of bone marrow transplantation (BMT) as a treatment for a wide variety of diseases, the numbers and types of cells required for both rapid and sustained recovery of hematopoiesis are not well defined. To investigate further the potential of transplants consisting of highly enriched populations of long-term repopulating cells, we transplanted a series of Ly-5.2 mice given various doses (750, 800, 850, 900, or 950 cGy) of total-body irradiation (TBI) with 30 or 90 Sca-1+Lin-WGA+ marrow cells isolated from congenic Ly-5.1 donors. As expected, mature progeny derived from these cells, belonging to both myeloid and lymphoid compartments, could be detected with increasing case in recipients given radiation doses from 750 to 900 cGy TBI. Surprisingly, expression of this potential was significantly reduced in mice that had received 950 cGy TBI. This contrasts with the capacity of the same number of purified Sca-1+Lin-WGA+ cells to generate readily detectable progeny in 950 cGy treated mice given a simultaneous transplant of 10(5) normal marrow cells or 2 x 10(5) serially passaged marrow cells. We suggest that this variable behavior of purified stem cells in differently treated recipients may reflect radiation dose-dependent differences in the types or levels of expression of factors that regulate transplanted stem cell proliferation and differentiation in vivo and that above a certain threshold radiation dose, this may result in an irreversible loss of long-term reconstituting potential. Regardless of the nature of the underlying mechanism, this study shows that the extent of donor repopulation after BMT can be a function not only of the number of stem cells transplanted but also of the conditioning of the recipient and whether other cell types are also injected.

The activity of hippocampal interneurons and pyramidal cells during the response of the hippocampus to repeated auditory stimuli

Interneurons and pyramidal cells were identified electrophysiologically in the hippocampus of anesthetized rats. Paired tones were presented 500 ms apart, and the resulting neuronal response was compared to differences in the amplitude of an auditory evoked potential (N40) elicited by each of the tones. Generally, the N40 elicited in response to the second tone is less than the response to the first. Pyramidal cells exhibited their most pronounced activation within 40 ms after the first tone. The post-stimulus discharge activation of interneurons was less than the pyramidal cells, but activation of different interneurons occurred at various times throughout the interval between the two tones. The presence or absence of suppression of N40 amplitude in the paired stimulus paradigm correlated with differences in the auditory response of both the interneurons and pyramidal cells. The activity of interneurons in relationship to gating of hippocampal auditory response is discussed.

Long-term potentiation disrupts auditory gating in the rat hippocampus

The consequence of long-term potentiation (LTP) of hippocampal commissural inputs was investigated in an auditory gating paradigm. Auditory evoked potentials (AEPs) were recorded in the CA3b region of the hippocampus of rats anesthesitized with chloral hydrate. Two tones were delivered 0.5 sec apart; in this paradigm, the second AEP is diminished compared to the first. Electrical stimulation was applied to hippocampal commissural fibers to generate field potentials and population spikes which were recorded at the same site as the AEPs. LTP of the commissural input (initiated by three trains of 250 Hz/1 sec stimulation) was associated with changes in the AEPs: on average, the response to the first tone decreased and the response to the second tone increased, resulting in the disruption of auditory gating. When high-frequency stimulation of the commissural input failed to result in LTP, no effect on the AEPs was seen. If 3-(2-carboxypiperazin-4-yl)-propyl-L-phosphonic acid (CPP; 6 mg/kg, i.p.), an antagonist to the NMDA subclass of glutamate receptors, was administered prior to high-frequency stimulation, LTP induction was blocked and AEPs were not affected. Finally, reversal of LTP, achieved by high-frequency stimulation of CA3 input that was heterosynaptic to the particular commissural fibers at which the LTP was originally generated, caused disrupted auditory gating to return to normal. A model of reciprocal LTP and heterosynaptic depression of commissural and auditory input pathways is proposed to explain these findings.

Priming of locomotor initiation by electrical stimulation in the hypothalamus and preoptic region in the anesthetized rat

Electrical stimulation at a locomotor site can prime (i.e., shorten the latency to initiate) stepping elicited by subsequent stimulation of the same or a different site. We tested for the priming effect in representative sites along the medial forebrain bundle, and determined if its magnitude showed regional differences. Rats (n = 20) were anesthetized with Nembutal and held in a stereotaxic apparatus over a wheel. Stepping was detected by accelerometers attached to the hindlimbs. Priming and test trains of stimulation (0.5-ms cathodal pulses, 50 Hz, 25-75 microA, 7-9-s train duration) separated by 20 s were delivered every 90 s. When the priming and test stimulations were applied to the same site, the priming effects were similar along the entire extent of the medial forebrain bundle. When the priming and test sites were different, the priming effect depended on their relative positions. Anterior stimulation primed posterior sites at magnitude comparable to those produced by stimulating the same posterior site. Posterior stimulation primed anterior sites at a level half of that produced by stimulation of the same anterior site. This pattern was found for priming and test sites that were ipsilateral and contralateral. Priming is a general and robust phenomenon with properties that may be useful for studying locomotor initiation pathways.

Integral membrane protein 2 of Epstein-Barr virus regulates reactivation from latency through dominant negative effects on protein-tyrosine kinases

An Epstein-Barr virus-encoded protein, LMP2, blocks the effects of surface immunoglobulin (slg) cross-linking on calcium mobilization and on lytic reactivation of EBV in latently infected and growth-transformed primary human B lymphocytes. In wild-type EBV-transformed cells, LMP2 is constitutively tyrosine phosphorylated and is associated with Lyn and Syk protein-tyrosine kinases (PTKs). Baseline Lyn PTK activity is substantially reduced, and slg cross-linking fails to activate Lyn, Syk, Pl3-K, PLC gamma 2, Vav, Shc, and MAPK. Syk, Pl3-K, PLC gamma 2, and Vav are constitutively tyrosine phosphorylated, and their tyrosine phosphorylation does not change following slg cross-linking. In contrast, cross-linking slg on cells transformed by LMP2 null mutant EBV recombinants triggers the same protein tyrosine kinase cascade as in noninfected B lymphocytes. These data are consistent with a model in which LMP2 is a constitutive dominant negative modulator of slg receptor signaling through its effects on Lyn, Syk, or regulators of these kinases.

Monitoring protein kinase and phosphatase reactions with matrix-assisted laser desorption/ionization mass spectrometry and capillary zone electrophoresis: comparison of the detection efficiency of peptide-phosphopeptide mixtures

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) and capillary zone electrophoresis (CZE) were evaluated for monitoring protein phosphatase and kinase reactions in vitro. Varying concentrations of peptide C (YIHLEKKYVRRDSG), peptide S (YLIEDNEYTARQGA) and kemptide (LARRSALG) mixed with their corresponding phosphorylated peptides, pC, pS and pkemptide, were analyzed. Comparison between the two techniques indicated that MALDI MS was less quantitative than CZE, showing a bias towards detection of the unphosphorylated peptide S and kemptide. In terms of sensitivity, the MALDI MS and CZE techniques are comparable. Protein kinase A phosphorylation of kemptide was monitored with both MALDI MS and CZE, whereas alkaline phosphatase dephosphorylation of pC could only be monitored with MALDI MS. The absence of inhibition with phosphatase or kinase buffers is a significant advantage of MALDI MS. In contrast to CZE, the MALDI spectra allow identification of the species analyzed by virtue of their mass. The results obtained emphasize the advantage of monitoring enzymatic reactions in buffer solutions using MALDI MS compared with CZE.