Executing plans to enhance diversity across cancer centers in the United States: Opportunities and challenges

BACKGROUND

Lack of diversity in the cancer research workforce persists which the new requirement for all NCI-designated cancer centers to have a Plan to Enhance Diversity (PED) seeks to address. However, it is not well understood how different cancer centers are approaching the development and execution of these plans. Our objective was to assess how cancer centers are establishing and pursuing their PED.

METHODS

We conducted a cross-sectional survey of members of the Cancer Center DEI Network which includes all NCI-designated cancer centers and several emerging centers. 62 cancer centers (75% of those invited), including 58 NCI-designated cancer centers (81% of those with this designation), participated and completed a questionnaire that assessed PED leadership, major challenges, implementation strategies, and approach to evaluate PED progress.

RESULTS

The most common PED challenge identified is recruiting diverse faculty (68% of centers) and the most common strategy currently used to address this is reviewing and revising faculty recruitment practices (67%). The most common approach centers are using to measure PED progress are shifts in demographics (68%), and data on the demographics of faculty, leadership, and trainees are available at 79%, 81%, and 75% of centers, respectively.

CONCLUSION(S)

While almost all centers have established a PED leadership structure, there is considerable variation in the approaches used to realize PED goals, and in the resources provided to support PED work. Realizing opportunities to share and implement common best practices and exemplar programs has the potential to elevate the impact of PED efforts nationally.

Family director board governance index: An analysis of family directors and firm performance in Malaysia

This study constructs a family director board governance index (FBGI) and examines its impact on the firm performance. This motivation is prompted by the literature and theoretical gaps. Despite the pervasiveness of family firms around the world and their significant contribution to the economy, past studies have not developed a board governance index to address the Type II agency conflict in family firms. A panel data of 1105 firm-year observations based on 221 family firms from 2016 to 2020 is used in this study. Two-way fixed-effects estimation with cluster-robust standard errors is employed to examine the association between the proposed FBGI and firm performance. System generalized method of moments is adopted to validate the results. The statistical results report a significant negative association between FBGI and firm performance. The findings suggest that Malaysian family firms have the tendency to tailor the board composition, and such composition is detrimental to the firm performance. The proposed index may be useful for the policy-makers and regulators to assess the board composition and governance role of family directors in Malaysian family firms. Furthermore, the index may be of interest to the potential investors of family firms when evaluating the board governance and making investment decisions.

NCOG-38. PREDICTORS OF COGNITIVE PERFORMANCE IN PATIENTS WITH PRIMARY BRAIN TUMORS: AN ANALYSIS OF BRAIN FITNESS CENTER (BFC) AT WALTER REED NATIONAL MILITARY MEDICAL CENTER

INTRODUCTION

Although developed initially for patients with traumatic brain injury (TBI), cognitive rehabilitation training (CRT) has expanded its use to include patients suffering from a variety of neurocognitive disorders including neurologic malignancies. The Brain Fitness Center (BFC) at Walter Reed National Military Medical Center (WRNMMC) is a cognitive rehabilitation clinic that offers computer-based cognitive training programs as an adjunctive rehabilitation resource for a diverse patient population with cognitive complaints.

METHODS

Using a retrospective analysis of data from the BFC at WRNMMC, our study analyzed forty patients with primary brain tumors who had completed both symptom self-report questionnaires and cognitive assessments at the BFC. Self-report questionnaires included the neurobehavioral symptom inventory (NSI) and headache symptom inventory (HIT-6) while cognitive assessments were done using the Automated Neuropsychological Assessment Metrics (ANAM). Our study examined the relationship between subjective cognitive complaints, headache severity, neuropsychiatric symptoms and objective cognitive performance before and after initial CRT. The influence of high vs low grade tumors was also evaluated.

RESULTS

Our analysis demonstrated that increased number of affective symptoms, particularly self-reported irritability, were the strongest predictors of baseline, objective cognitive performance (r= -.377, p=0.008). Patient self-reported forgetfulness, but not overall subjective cognitive complaints, was also negatively correlated with objective cognitive performance (r= - 0.353, p= 0.020). A mean difference in objective cognitive performance between high grade and low grade tumors was also found (p=0.003).

CONCLUSIONS

Our results point to potential patient-level factors which could predict benefit from CRT including self-reported irritability, self-reported forgetfulness, and tumor grade. Further prospective studies will help to examine the true benefit of sustained CRT, and the subset of patients with CNS neoplasms most likely to benefit from this training.

The Framingham risk score underestimates the risk of cardiovascular events in the HER2-positive breast cancer population

INTRODUCTION

Patients with breast cancer (bca) who overexpress her2 (the human epidermal growth factor receptor 2) are at risk for cardiotoxicity when treated with anthracycline-based chemotherapy and her2-targeted agents. The Framingham risk score (frs) is a validated tool that stratifies patients into high-, intermediate-, or low-risk groups and calculates their 10-year risk of developing cardiovascular disease (cvd) based on past medical history, systolic blood pressure, and measurement of serum lipids. We retrospectively analyzed patients with her2-positive bca to determine whether the frs predicts adverse cardiovascular (CV) events or cardiotoxicity in patients treated using anthracyclines or her2-targeted therapy, or both.

METHODS

The frs was determined for patients with bca referred to The Ottawa Hospital Cardiology-Oncology Clinic from October 2008 to August 2014. The patients were stratified into high (≥20%), intermediate (10%-20%), and low (<10%) 10-year cv risk groups. Primary outcomes included cvd-related hospitalizations and deaths, and cardiotoxicity [drop in left ventricular ejection fraction (lvef) of >10% to a lvef ≤50%].

RESULTS

Of the 152 patients included in the analysis (median follow-up: 40.7 months; range: 3.5-263 months), 47 (31%) were classified as high risk; 36 (24%), as intermediate risk; and 69 (45%), as low-risk. The number of cvd-related hospitalizations and deaths was 22, for an overall prevalence of 14%, with significantly more events occurring in high-risk than in low-risk patients (odds ratio: 4.18; 95% confidence limits: 1.47, 11.89). The frs predicted a 10-year risk of any cv event of 11.2% and underestimated the actual rate of cv events in the entire cohort. High frs was not associated with cardiotoxicity (p = 0.82).

CONCLUSIONS

In a population of patients with her2-positive bca referred to a cardiology-oncology clinic, the frs does not accurately predict the risk of cv events or cardiotoxicity.

An App a Day Keeps the Doctor Away: Guided Education and Training via Smartphones in Subthreshold Post Traumatic Stress Disorder

Post traumatic stress disorder (PTSD) symptoms are common in military service members (SMs), but stigma can impede treatment initiation. Smartphone applications (apps) are available anywhere, anytime, with the potential to both mitigate the impact of stigma and reduce PTSD symptom severity. We provided 144 SMs or family members, with subthreshold PTSD symptoms (PTSD Checklist [PCL] scores of 28-49), with apps promoting psychoeducation, social engagement, and relaxation and randomized them to 6 weeks of resilience enhancement (brief cognitive-behavioral session, followed by daily text messages directing app use) or a control group (daily text messages of inspirational quotes). Participants (54 percent males, 87 percent SMs) in both groups reported reductions in PTSD, anxiety, and depression symptoms during the 6-week intervention, which were sustained at 3 months, but exhibited partial rebound at 6-12 months. Our preliminary results suggest that app use, with or without specific direction, feasibly and effectively reduces symptom severity. Future studies should consider a longer intervention, enhanced compliance tracking, or boosters to sustain benefits.

Traditional preparations of kava (Piper methysticum) inhibit the growth of human colon cancer cells in vitro

BACKGROUND

Epidemiological studies indicate there is low incidence of colon cancer in the South Pacific islands, including Fiji, West Samoa, and Vanuatu. Cancer incidence has been shown to be inversely associated with kava (Piper methysticum G. Forst.) ingestion. Hypothesis/Purpose: Kava prepared traditionally will inhibit the growth of human cancer cells. This investigation entails preparation and analysis of kava extracts and study of the growth inhibitory activity of the extracts, alone and combined with hibiscus.

STUDY DESIGN

We will prepare kava as in Micronesia - as a water extract, high in particulate content, alone or combined with sea hibiscus (Hibiscus tiliaceus L.) - and examine the components and growth inhibitory activity.

METHODS

We obtained ground kava prepared in the traditional way from lateral roots and sea hibiscus mucilage and sap from different sources in Micronesia, and prepared water extracts (unfiltered, as well as filtered, since in traditional use the kava beverage contains a high particulate content) and partitions. We used the MTT assay to determine the growth inhibitory activity of the preparations on colon and breast cancer cells and nonmalignant intestinal epithelial cells. LC-MS analysis was used to examine the components of the kava and sea hibiscus extracts and partitions.

RESULTS

Traditional preparations of kava inhibit the growth of breast and colon cancer cells. Among the kava preparations, the order of decreasing activity was Fiji(2), Fiji(1), Hawaii; the unfiltered preparations from Fiji were more active than the filtered. Phytochemical analysis indicated that filtering reduced most kavalactone and chalcone content. For example, for Fiji(2), the ratio of dihydromethysticin in filtered/unfiltered kava was 0.01. Thus, for the extracts from Fiji, growth inhibitory activity correlates with the content of these compounds. Unfiltered and filtered kava from Fiji(1) were more active on malignant than nonmalignant intestinal epithelial cells. Since kava is prepared in Micronesia by squeezing the extract through sea hibiscus bark, we assayed the growth inhibitory activity of combinations of kava and sea hibiscus sap and found that sea hibiscus enhanced the growth inhibitory effect of kava.

CONCLUSION

Our results show that traditional kava, alone or combined with sea hibiscus, displays activity against human cancer cells and indicate it will be worthwhile to develop and further analyze these preparations to prevent and treat colon and other cancers. Our findings suggest it is important to examine the activity of plants in the form that people consume them.

Improving the Climate in Research and Scientific Training Environments for Members of Underrepresented Minorities

Despite significant efforts in recent years to increase diversity in science and academia, African Americans, Hispanics, and American Indian/Alaskan Natives remain severely underrepresented in these fields. To date, institutional social climate has received little attention as a target to improve the representation of these minority groups. In this article, we suggest that improvement in the social climate in both individual laboratories and larger institutions may lead to better recruitment and retention of minorities in science and academia. After documenting the magnitude of the underrepresentation problem, we offer a framework for a better understanding of climate, illustrate how members of majority and minority groups may perceive climate differently, and provide specific recommendations for improving the climate. The benefits of a diverse workforce in the sciences include a commitment to social justice, a broad diversity of perspectives leading to greater opportunities for scientific advancement, and a potentially enhanced focus on understanding and eliminating the health disparities among different racial and ethnic groups.

Predictors of Neurocognitive Syndromes in Combat Veterans

Traumatic brain injury, depression and posttraumatic stress disorder (PTSD) are neurocognitive syndromes often associated with impairment of physical and mental health, as well as functional status. These syndromes are also frequent in military service members (SMs) after combat, although their presentation is often delayed until months after their return. The objective of this prospective cohort study was the identification of independent predictors of neurocognitive syndromes upon return from deployment could facilitate early intervention to prevent disability. We completed a comprehensive baseline assessment, followed by serial evaluations at three, six, and 12 months, to assess for new-onset PTSD, depression, or postconcussive syndrome (PCS) in order to identify baseline factors most strongly associated with subsequent neurocognitive syndromes. On serial follow-up, seven participants developed at least one neurocognitive syndrome: five with PTSD, one with depression and PTSD, and one with PCS. On univariate analysis, 60 items were associated with syndrome development at p < 0.15. Decision trees and ensemble tree multivariate models yielded four common independent predictors of PTSD: right superior longitudinal fasciculus tract volume on MRI; resting state connectivity between the right amygdala and left superior temporal gyrus (BA41/42) on functional MRI; and single nucleotide polymorphisms in the genes coding for myelin basic protein as well as brain-derived neurotrophic factor. Our findings require follow-up studies with greater sample size and suggest that neuroimaging and molecular biomarkers may help distinguish those at high risk for post-deployment neurocognitive syndromes.

Effect of probiotic bacteria on the intestinal microbiota in irritable bowel syndrome

BACKGROUND AND AIM

In irritable bowel syndrome (IBS), the gut microbiota may be altered. Probiotic bacteria appear to be therapeutically effective. We characterized the mucosa-associated microbiota, and determined the clinical and microbiological effects of orally administered probiotic bacteria, in patients with IBS.

METHODS

Mucosal microbiota from rectal biopsies of IBS patients and controls were assessed on the V1 and V2 variable regions of the 16S ribosomal RNA gene amplified using 454 pyrosequencing. Clinical symptoms and changes in mucosal microbiota were assessed in IBS patients before and after 4 weeks of treatment with probiotic mix VSL#3.

RESULTS

Ten IBS subjects (eight female; mean age 46 years) were included. At week 4 of probiotic therapy, six patients showed symptom improvement on global symptom assessment compared with baseline (P = 0.031). Before therapy, intestinal microbiota of IBS subjects differed significantly from that of healthy controls, with less diversity and evenness than controls (n = 9; P < 0.05), increased abundance of Bacteroidetes (P = 0.014) and Synegitestes (P = 0.017), and reduced abundance of Actinobacteria (P = 0.004). The classes Flavobacteria (P = 0.028) and Epsilonproteobacteria (P = 0.017) were less enriched in IBS. Abundance differences were largely consistent from the phylum to genus level. Probiotic treatment in IBS patients was associated with a significant reduction of the genus Bacteroides (all taxonomy levels; P < 0.05) to levels similar to that of controls.

CONCLUSION

In this pilot study, global and deep molecular analysis demonstrates an altered mucosal microbiota composition in IBS. Probiotic leads to detectable changes in the microbiota. These effects of probiotic bacteria may contribute to their therapeutic benefit.

Installation and use of LabKey Server for proteomics

LabKey Server (formerly CPAS, the Computational Proteomics Analysis System) provides a Web-based platform for mining data from liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteomic experiments. This open source platform supports systematic proteomic analyses and secure data management, integration, and sharing. LabKey Server incorporates several tools currently used in proteomic analysis, including the X! Tandem search engine, the ProteoWizard toolkit, and the PeptideProphet and ProteinProphet data mining tools. These tools and others are integrated into LabKey Server, which provides an extensible architecture for developing high-throughput biological applications. The LabKey Server analysis pipeline acts on data in standardized file formats, so that researchers may use LabKey Server with other search engines, including Mascot or SEQUEST, that follow a standardized format for reporting search engine results. Supported builds of LabKey Server are freely available at http://www.labkey.com/. Documentation and source code are available under the Apache License 2.0 at http://www.labkey.org.

Improvement in cerebral function with treatment of posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI) are signature illnesses of the Iraq and Afghanistan wars, but current diagnostic and therapeutic measures for these conditions are suboptimal. In our study, functional magnetic resonance imaging (fMRI) is used to try to differentiate military service members with: PTSD and mTBI, PTSD alone, mTBI alone, and neither PTSD nor mTBI. Those with PTSD are then randomized to virtual reality exposure therapy or imaginal exposure. fMRI is repeated after treatment and along with the Clinician-Administered PTSD Scale (CAPS) and Clinical Global Impression (CGI) scores to compare with baseline. Twenty subjects have completed baseline fMRI scans, including four controls and one mTBI only; of 15 treated for PTSD, eight completed posttreatment scans. Most subjects have been male (93%) and Caucasian (83%), with a mean age of 34. Significant improvements are evident on fMRI scans, and corroborated by CGI scores, but CAPS scores improvements are modest. In conclusion, CGI scores and fMRI scans indicate significant improvement in PTSD in both treatment arms, though CAPS score improvements are less robust.

Integrative proteomic analysis of serum and peritoneal fluids helps identify proteins that are up-regulated in serum of women with ovarian cancer

BACKGROUND

We used intensive modern proteomics approaches to identify predictive proteins in ovary cancer. We identify up-regulated proteins in both serum and peritoneal fluid. To evaluate the overall performance of the approach we track the behavior of 20 validated markers across these experiments.

METHODOLOGY

Mass spectrometry based quantitative proteomics following extensive protein fractionation was used to compare serum of women with serous ovarian cancer to healthy women and women with benign ovarian tumors. Quantitation was achieved by isotopically labeling cysteine amino acids. Label-free mass spectrometry was used to compare peritoneal fluid taken from women with serous ovarian cancer and those with benign tumors. All data were integrated and annotated based on whether the proteins have been previously validated using antibody-based assays.

FINDINGS

We selected 54 quantified serum proteins and 358 peritoneal fluid proteins whose case-control differences exceeded a predefined threshold. Seventeen proteins were quantified in both materials and 14 are extracellular. Of 19 validated markers that were identified all were found in cancer peritoneal fluid and a subset of 7 were quantified in serum, with one of these proteins, IGFBP1, newly validated here.

CONCLUSION

Proteome profiling applied to symptomatic ovarian cancer cases identifies a large number of up-regulated serum proteins, many of which are or have been confirmed by immunoassays. The number of currently known validated markers is highest in peritoneal fluid, but they make up a higher percentage of the proteins observed in both serum and peritoneal fluid, suggesting that the 10 additional markers in this group may be high quality candidates.

Software platform for rapidly creating computational tools for mass spectrometry-based proteomics

We describe and demonstrate the proteomics computational toolkit provided in the open-source msInspect software distribution. The toolkit includes modules written in Java and in the R statistical programming language to aid the rapid development of proteomics software applications. It contains tools for processing and manipulating standard MS data files, including signal processing of LC-MS data and parsing of MS/MS search results, as well as for modeling proteomics data structures, creating charts, and other common tasks. We present this toolkit's capability to rapidly develop new computational tools by presenting an example application, Qurate, a graphical tool for manually curating isotopically labeled peptide quantitative events.

Peptide sequence confidence in accurate mass and time analysis and its use in complex proteomics experiments

We present new algorithms and a software implementation for assigning confidence to peptide sequence assignments obtained through classic accurate mass and retention time (AMT) matching techniques, as well as methods for integrating these assignments with standard proteomics workflows. The algorithms are intended to increase the number of peptides and proteins identified (and, when applicable, quantitated by isotopic labeling) among related proteomics experiments that use high-resolution mass spectrometry instrumentation. The motivations for our extensions include the need to exploit high-resolution data to support highly complex proteomics experiments, especially those involving extensive off-line fractionation, to which recent label-free workflows might not easily generalize.

Brain-specific proteins decline in the cerebrospinal fluid of humans with Huntington disease

We integrated five sets of proteomics data profiling the constituents of cerebrospinal fluid (CSF) derived from Huntington disease (HD)-affected and -unaffected individuals with genomics data profiling various human and mouse tissues, including the human HD brain. Based on an integrated analysis, we found that brain-specific proteins are 1.8 times more likely to be observed in CSF than in plasma, that brain-specific proteins tend to decrease in HD CSF compared with unaffected CSF, and that 81% of brain-specific proteins have quantitative changes concordant with transcriptional changes identified in different regions of HD brain. The proteins found to increase in HD CSF tend to be liver-associated. These protein changes are consistent with neurodegeneration, microgliosis, and astrocytosis known to occur in HD. We also discuss concordance between laboratories and find that ratios of individual proteins can vary greatly, but the overall trends with respect to brain or liver specificity were consistent. Concordance is highest between the two laboratories observing the largest numbers of proteins.

Installation and use of the Computational Proteomics Analysis System (CPAS)

The community of proteomic researchers has been generating openly available software infrastructure for systematic proteomic data analyses and data management for the past several years. The Computational Proteomics Analysis System (CPAS) integrates many of these efforts into a single Web-based platform for mining liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteomic experiments. CPAS incorporates several tools currently used in proteomic analysis, including the X! Tandem search engine and the PeptideProphet and ProteinProphet data mining tools. These tools and others are integrated into a single application built on the open-source LabKey platform, an extensible architecture for developing high-throughput biological applications. The CPAS analysis pipeline acts on data in standardized file formats, so that researchers may use CPAS with other search engines, including Mascot or SEQUEST, that follow a standardized procedure for reporting search engine results. All components of the CPAS toolkit are freely available at http://cpas.fhcrc.org.

Open-source platform for the analysis of liquid chromatography-mass spectrometry (LC-MS) data

The analysis of protein mixtures by liquid chromatography-mass spectrometry (LCMS) requires tools for viewing and navigating LC-MS data, locating peptides in LC-MS data, and eliminating low-quality peptides. msInspect, an open source platform, can carry out these steps for single experiments and can align and normalize peptide features in comparative studies with multiple LC-MS runs. In addition, msInspect can analyze quantitative studies with and without isotopic labels to generate peptide arrays.

What factors influence Hong Kong school students in their choice of a career in nursing?

Chronic and recurrent shortages of nurses, coupled with the increasing demand for high quality and motivated nurses and competition for secondary school leavers from other professions, are issues which prompted this investigation of senior school students' career choice. Using a descriptive survey design, and a questionnaire developed for the study, 1246 Form 6 students in Hong Kong were surveyed, of these 28% respondents reported that they were interested in studying nursing. The findings indicated that students' decision to choose or not choose nursing was significantly influenced by the demographic factors: gender (chi(2) = 42.72, p < 0.0005), biology subject pursued (chi(2) = 18.94, p < 0.0005), previous academic achievement (chi(2) = 34.33, p < 0.0005) and mother's occupation (chi(2) = 21.08, p = 0.012); and their perception of nursing as a career score (t = 14.21, df = 1237, p < 0.0005). Students' intention to study nursing was also significantly affected by social influence: parents (chi(2) = 11.53, p = 0.001), school career masters (chi(2) = 5.52, p = 0.019) and friends (chi(2) = 4.83, p = 0.028); past experience with career activities (chi(2) = 84.479, p < 0.005); and working in hospital (chi(2) = 31.742, p < 0.005). Backward elimination logistic regression analysis concluded that being female (p < 0.0005), biology study at Form 5 and A-level (p < 0.0005), total perception scores (p < 0.0005), and participation in career activities (p < 0.0005) were found to be predictors of the students' intention to study nursing. Results of this study can be used by nurse leaders and recruiters to develop strategies and help school leavers perceive nursing in a more positive way. Expanding the informational sources about nursing can facilitate the recruitment process.

High production of heterologous proteins in Escherichia coli using the thermo-regulated T7 expression system

The exclusive use of isopropyl beta-D-thiogalactopyranoside to activate the T7 promoter for protein production has limited the general use of the expression system. We have sought an alternative by constructing a recombinant Escherichia coli strain, BL21 (G2), to carry a chromosomal copy of T7 gene 1 fused to the lambdaPL and lambdaP(R) tandem promoter. As a result, the recombinant strain harboring the carbamoylase gene from Agrobacterium radiobacter NRRL B11291 was shown to display various levels of.protein production in response to different degrees of heat shock. In particular, the system remained inactive at 30 degrees C and exhibited high sensitivity to heat such that a detectable carbamoylase activity could be measured after exposure to 33 degrees C. Moreover, heating in two steps - elevating the temperature from 30 degrees C to 39 degrees C and holding for a brief period, followed by reducing to 37 degrees C--was found to be the most potent method for protein production in this case. Using this approach, the recombinant protein accounted for 20% of total protein content of the cell. These results reveal the advantages of this expression system: responsiveness to thermal modulation and high-level production capability. In an attempt to enhance the total protein yield, a fed-batch fermentation process was carried out to control the cell growth rate by adjusting the substrate inflow. By applying the two-step temperature change. a carbamoylase yield with enzyme activity corresponding to 14,256 units was obtained. This production yield is a 10-fold increase in comparison with that at the batch-fermentation scale and 2,000-fold higher than that achieved at the shake-flask scale. Overall, it illustrates the promise of the newly constructed T7 system based on heat inducibility for industrial scale production of recombinant proteins.

Transforming ability of Gag-Myc fusion proteins correlates with Gag-Myc protein stability and transcriptional repression

Avian retroviruses that have transduced c-myc are useful tools to study the conditions necessary for cellular transformation. FH3, one such retrovirus which encodes a Gag-Myc fusion protein, is not transforming in quail embryonic fibroblasts, but a late variant of FH3 that arose after passaging FH3-infected cells is transforming. Mutational analysis of FH3 revealed that the presence of a portion of the retroviral protease in FH3 inhibited transformation and that this inhibition was transferable to a more highly transforming retrovirus, MC29. Transforming and non-transforming FH3-derived and MC29-derived Gag-Myc proteins were used to further explore characteristics of Myc necessary for transformation. Gag-Myc proteins which were transforming were found to be the most stable in the cell. To distinguish whether transactivation and/or repression is correlated to transformation, the various Gag-Myc fusion proteins were tested for their ability to activate or repress c-Myc targets. Results indicated that a correlation exists between transforming Gag-Myc proteins and their ability to repress, whereas all Gag-Myc proteins could transactivate, regardless of their ability to transform. Taken together, these results suggest that protein stabilization of Myc and repression of target genes by Myc are important for cellular transformation.

Thymic dendritic cells are primary targets for the oncogenic virus SL3-3

The murine retrovirus SL3-3 causes malignant transformation of thymocytes and thymic lymphoma in mice of the AKR and NFS strains when they are inoculated neonatally. The objective of the present study was to identify the primary target cells for the virus in the thymuses of these mice. Immunohistochemical studies of the thymus after neonatal inoculation of the SL3-3 virus showed that cells expressing the viral envelope glycoprotein (gp70(+) cells) were first seen at 2 weeks of age. These virus-expressing cells were found in the cortex and at the corticomedullary junction in both mouse strains. The gp70(+) cells had the morphology and immunophenotype of dendritic cells. They lacked macrophage-specific antigens. Cell separation studies showed that bright gp70(+) cells were detected in a fraction enriched for dendritic cells. At 3 weeks of age, macrophages also expressed gp70. At that time, both gp70(+) dendritic cells and macrophages were found at the corticomedullary junction and in foci in the thymic cortex. At no time during this 3-week period was the virus expressed in cortical and medullary epithelial cells or in thymic lymphoid cells. Infectious cell center assays indicated that cells expressing infectious virus were present in small numbers at 2 weeks after inoculation but increased at 5 weeks of age by several orders of magnitude, indicating virus spread to the thymic lymphoid cells. Thus, at 2 weeks after neonatal inoculation of SL3-3, thymic dendritic cells are the first cells to express the virus. At 3 weeks of age, macrophages also express the virus. In subsequent weeks, the virus spreads to the thymocytes. This pathway of virus expression in the thymus allows the inevitable provirus integration in a thymocyte that results in a clonal lymphoma.

Breakdown and release of myofilament proteins during ischemia and ischemia/reperfusion in rat hearts: identification of degradation products and effects on the pCa-force relation

Our objective in experiments reported here was to identify myofilament proteins of rat hearts either lost or degraded by cardiac ischemia (15- or 60-minute duration) with and without 45 minutes of reperfusion. We correlated these changes with alterations in myofilament sensitivity to Ca2+ and maximum force generation. Protein degradation and loss were assessed by high-performance liquid chromatography, SDS-PAGE, Western blotting analysis, and amino acid sequencing. Compared with nonischemic control hearts, bundles of skinned fibers from hearts subjected to ischemia alone demonstrated a decrease in maximum force generation and an increase in sensitivity to Ca2+. These changes in function were increased with the duration of the ischemia and with reperfusion. With increasing duration of ischemia, there was an increased loss and degradation of myofibrillar alpha-actinin and troponin I (TnI) at its C-terminus. Alpha-actinin and TnI were most susceptible to ischemia, but with 60 minutes of ischemia/reperfusion, there was also degradation of myosin light chain-1 (MLC1) involving a clip of residues 1 to 19. The MLC1 degradation product was detected in the reperfusion effluent (along with troponin T, tropomyosin, and alpha-actinin) but not in the tissue with 60 minutes of ischemia with no reperfusion. Moreover, with ischemia the following proteins became associated with the myofibrils: GAPDH and proteins of the mitochondrial ATP synthase complex. Our results provide new evidence regarding the mechanism by which ischemia/reperfusion causes myocardial injury and support the hypothesis that an important element in the injury is altered activity and structure of the myofilaments.

Postdisaster psychosocial intervention: a field study of the impact of debriefing on psychological distress

OBJECTIVE

Following a catastrophic natural disaster, the authors evaluated whether brief psychological intervention (debriefing 6 months later) reduced disaster-related psychological distress as measured by the Impact of Event Scale.

METHOD

Two groups of subjects who had been exposed to Hurricane Iniki in Hawaii were assessed before and after participating in a multihour debriefing group. The intervention aimed to provide ventilation of feelings, normalization of responses, and education about normal psychological reactions to the disaster in a context of group support. To provide a partial control for the passage of time, the pretreatment assessment of the second group was concurrent with the posttreatment assessment of the first group.

RESULTS

A repeated measures analysis of variance indicated that Impact of Event Scale scores were reduced in both groups after the treatment.

CONCLUSIONS

There is preliminary empirical support for the effectiveness of postdisaster psychological intervention and for the feasibility of treatment research in postdisaster environments.

Cell-surface receptors for gibbon ape leukemia virus and amphotropic murine retrovirus are inducible sodium-dependent phosphate symporters

Cell surface receptors for gibbon ape leukemia virus (Glvr-1) and murine amphotropic retrovirus (Ram-1) are distinct but related proteins having multiple membrane-spanning regions. Distant homology with a putative phosphate permease of Neurospora crassa suggested that these receptors might serve transport functions. By expression in Xenopus laevis oocytes and in mammalian cells, we have identified Glvr-1 and Ram-1 as sodium-dependent phosphate symporters. Two-electrode voltage-clamp analysis indicates net cation influx, suggesting that phosphate is transported with excess sodium ions. Phosphate uptake was reduced by > 50% in mouse fibroblasts expressing amphotropic envelope glycoprotein, which binds to Ram-1, indicating that Ram-1 is a major phosphate transporter in these cells. RNA analysis shows wide but distinct tissue distributions, with Glvr-1 expression being highest in bone marrow and Ram-1 in heart. Overexpression of Ram-1 severely repressed Glvr-1 synthesis in fibroblasts, suggesting that transporter expression may be controlled by net phosphate accumulation. Accordingly, depletion of extracellular phosphate increased Ram-1 and Glvr-1 expression 3- to 5-fold. These results suggest simple methods to modulate retroviral receptor expression, with possible applications to human gene therapy.

Withdrawal symptoms after graduated cessation of imipramine in children

In a systematic retrospective study the authors reviewed charts of 22 depressed children on a clinical research unit who were withdrawn from high-dose imipramine. Significant withdrawal symptoms were found over seven symptom categories despite an average tapering period of 6.4 days. These results suggest that withdrawal symptoms in children may be much more prevalent and intense than previously recognized.

Regulation of erythropoiesis in diabetes mellitus

The regulation of erythropoiesis in 40 subjects with diabetes mellitus was investigated to test the hypothesis that increased blood concentrations of glycosylated hemoglobin would produce a reduced p50 and a compensatory increase in erythropoietin. Little evidence to support this hypothesis was observed. However, diabetes did produce complex changes in hemoglobin-oxygen releasing capacity which were compensated for in the expected way, i.e. oxygen releasing capacity showed an inverse correlation with erythropoietin. We conclude that the effects of diabetes on erythropoiesis are minor and probably have no pathological significance in most patients suffering from this disease.