Hypercalcemia of malignancy caused by parathyroid hormone-related peptide-secreting pancreatic neuroendocrine tumors (PTHrP-PNETs): Case Report

Parathyroid hormone-related protein (PTHrP) secretion is occasionally detected in various solid tumors such as renal cell carcinoma and lung cancers. It is considered quite rare for neuroendocrine tumors with only few published case reports. We reviewed the current literature and summarized a case report of a patient with metastatic pancreatic neuroendocrine tumor (PNET) presenting with hypercalcemia due to elevation of PTHrP. The patient had histological confirmation of well-differentiated PNET and developed hypercalcemia years after his initial diagnosis. In our case report, evaluation showed intact parathyroid hormone (PTH) in the setting of concomitant elevation of PTHrP. The patient's hypercalcemia and PTHrP levels were improved by using a long-acting somatostatin analogue. In addition, we reviewed the current literature regarding the optimal management of malignant hypercalcemia due to PTHrP-producing PNETs.

Expression of RNA polymerase I catalytic core is influenced by RPA12

RNA Polymerase I (Pol I) has recently been recognized as a cancer therapeutic target. The activity of this enzyme is essential for ribosome biogenesis and is universally activated in cancers. The enzymatic activity of this multi-subunit complex resides in its catalytic core composed of RPA194, RPA135, and RPA12, a subunit with functions in RNA cleavage, transcription initiation and elongation. Here we explore whether RPA12 influences the regulation of RPA194 in human cancer cells. We use a specific small-molecule Pol I inhibitor BMH-21 that inhibits transcription initiation, elongation and ultimately activates the degradation of Pol I catalytic subunit RPA194. We show that silencing RPA12 causes alterations in the expression and localization of Pol I subunits RPA194 and RPA135. Furthermore, we find that despite these alterations not only does the Pol I core complex between RPA194 and RPA135 remain intact upon RPA12 knockdown, but the transcription of Pol I and its engagement with chromatin remain unaffected. The BMH-21-mediated degradation of RPA194 was independent of RPA12 suggesting that RPA12 affects the basal expression, but not the drug-inducible turnover of RPA194. These studies add to knowledge defining regulatory factors for the expression of this Pol I catalytic subunit.

Identification of an E3 ligase that targets the catalytic subunit of RNA Polymerase I upon transcription stress

RNA Polymerase I (Pol I) synthesizes rRNA, which is the first and rate-limiting step in ribosome biogenesis. Factors governing the stability of the polymerase complex are not known. Previous studies characterizing Pol I inhibitor BMH-21 revealed a transcriptional stress-dependent pathway for degradation of the largest subunit of Pol I, RPA194. To identify the E3 ligase(s) involved, we conducted a cell-based RNAi screen for ubiquitin pathway genes. We establish Skp-Cullin-F-box protein complex F-box protein FBXL14 as an E3 ligase for RPA194. We show that FBXL14 binds to RPA194 and mediates RPA194 ubiquitination and degradation in cancer cells treated with BMH-21. Mutation analysis in yeast identified lysines 1150, 1153, and 1156 on Rpa190 relevant for the protein degradation. These results reveal the regulated turnover of Pol I, showing that the stability of the catalytic subunit is controlled by the F-box protein FBXL14 in response to transcription stress.

Abstract 3247: Functional CRISPR-Cas9 screens identify master regulators of resistance to chemical targeting of RNA polymerase I

Increased ribosome biogenesis is a hallmark of cancer and targeting this process with RNA polymerase I (Pol I) inhibitors is a promising strategy for cancer therapy. BMH-21 is a first-in-class small molecule that inhibits Pol I transcription and induces degradation of the enzyme. This approach is effective across many cancer types. However, a heterogeneous response was observed in cancer cell lines emphasizing the need to increase knowledge of factors that underlie the response to this therapeutic strategy. To identify genes that modulate the response of cancer cells to BMH-21, we performed genome-wide CRISPR-Cas9-based positive selection screens in human colorectal carcinoma cells. These screens identified high-confidence hits accounting for BMH-21 drug resistance that included all key positive regulators of the mTORC1 complex. Given that p53 has been identified as a downstream effector of Pol I transcription stress, we conducted the screens in TP53 isogenic cells. Notably, the mTORC1 pathway hits were identified in all screens indicating that the resistance was p53 independent. These findings are particularly striking given that mTOR is a major driver of ribosome biogenesis and cellular translational programs. The findings were validated using chemical and genetic approaches. Torin-1, a catalytic mTOR inhibitor, was found to cause resistance to BMH-21. mTOR signaling pathway knockout and rescue cell lines were generated and tested for changes in the drug responses by growth, viability, colony formation and GFP competition assays. In each case, compromised mTOR activity led to resistance to BMH-21. However, compromised mTOR activity did not abrogate Pol I transcription inhibition by BMH-21. To assess impact on protein translation, we used polysome profiling. BMH-21 treatment was found to cause a severe ribosome biogenesis defect. Surprisingly, mTOR inactivation partially rescued the translation ability under the drug treatment suggesting that this translation is pivotal for cell survival. To uncover factors critical for the survival, we performed Ribo-seq and RNA-seq in the drug-treated BMH-21 sensitive and resistant cells. The profiling results revealed that mTOR inactivation led to elevated translation efficiency of mRNAs encoding ribosomal proteins. These findings suggest that mTOR inactivation evokes compensatory selective translation of ribosomal proteins under severe ribosome biogenesis defect caused by the Pol I inhibition. The findings indicate that mTOR inactivation regulates selective translation as means to bypass Pol I inhibition, and more generally, that maintenance of translational capacity strongly contributes to treatment resistance. These findings reveal an unexpected complication by mTOR inhibitory strategies as well as have implications on exploring drug combinations in cancer.

Citation Format: Wenjun Fan, Hester Liu, Stephanie Pitts, Brittany Ford, Rajeshkumar NV, Marikki Laiho. Functional CRISPR-Cas9 screens identify master regulators of resistance to chemical targeting of RNA polymerase I [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3247.

Abstract 2644: Therapeutic inhibition of RNA polymerase I reveals vulnerability of mismatch repair defective cancers

RNA polymerase I inhibitors represent a new class of cancer therapeutics with potential application in many cancer types. By curbing the transcription of ribosomal RNAs they block the rate-limiting step in ribosome biogenesis and protein synthesis. We have recently identified specific and selective first-in-class inhibitors of Pol I. This class of Pol I inhibitors, represented by small-molecule BMH-21, blocks transcription initiation and elongation and causes the destruction of the enzyme catalytic subunit. BMH-21 activity is genetically dependent on Pol I in cancer cells and in yeast confirming the targeting specificity. Our earlier mechanistic and efficacy studies with BMH-21 have demonstrated the utility of the approach in targeting colon and prostate cancers and melanoma. The goal of this study was to pinpoint cancer types with specific sensitivity to these inhibitors and to identify markers of this sensitivity. To do so, we undertook unbiased large-scale cancer cell line screens with our Pol I inhibitors and conducted correlative analyses using open source DepMap and Achilles databases to identify cancer types and features that sensitize cancer cells to these inhibitors. The most sensitive lineages were colorectal, endometrial, esophageal, leukemia, myeloma, and ovarian. Comparison of the cancer cell line responses to the Achilles gene essentiality database showed high correlation to genetic knock-out of three Pol I subunits. This unbiased finding strongly supports identification of Pol I as the target. Further, we identified two ribosomal proteins, RPL22 and RPL22L1 as the top genetic and expression markers denoting sensitivity, and MDM4, a p53 transcriptional repressor, as the top protein marker. Together, these three markers conform to a new p53 regulatory pathway. These findings were validated using genetic and mechanistic analyses. We show that Pol I inhibition alters the MDM4 splicing and decreases the expression of MDM4 isoform that represses p53, and that this activity is dependent on the RPL22/RPL22L1 proteins. Notably, perturbation of the biomarkers is strongly associated with mismatch repair defective (MMRd) cancers. We show the efficacy of the Pol I inhibitors in xenograft and patient-derived MMRd models. Our data suggest that RPL22mutation could serve as tumor-agnostic biomarker for targeting cancers with the Pol I inhibitors. Furthermore, this work identifies a new Pol I transcription-dependent ribosomal protein-governed pathway that converges on the regulation of p53.

Citation Format: Wenjun Fan, Hester Liu, Asma Begum, Stephanie Pitts, Brittany Ford, Tony Dorado, Pablo de Leon, Rajeshkumar NV, James C. Barrow, Marikki Laiho. Therapeutic inhibition of RNA polymerase I reveals vulnerability of mismatch repair defective cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2644.

Abstract 678: Identification of an E3 ligase regulating the catalytic subunit of RNA polymerase I

RNA polymerase I (Pol I) is responsible for the transcription of ribosomal DNA (rDNA), the first and rate-limiting step of ribosome biogenesis. Pol I is the most active RNA polymerase, and it comprises over 60% of transcriptional activity in cancer cells. The robust transcriptional activity, coupled with the high density of elongating Pol I transcription complexes on the rDNA, renders Pol I vulnerable to transcriptional blocks. In healthy cells, this type of transcriptional stress activates inhibitory downstream cascades such as the p53 pathway. However, cancer cells elude this regulatory mechanism to sustain high levels of growth. Further, oncogenic drivers upregulate Pol I activity and achieve abnormally high rates of ribosome biogenesis. This makes Pol I a highly relevant target for cancer therapeutics. Yet little is known about the stability and regulation of the enzyme complex and whether this knowledge can be used for therapeutic purposes. Our lab recently discovered a first-in-class small molecule, BMH-21, that inhibits Pol I transcription and induces the degradation of the catalytic subunit of Pol I, RPA194. We showed that the inducible degradation of RPA194 is cancer cell-specific, correlated with cell death, and is mediated by the proteasome system. A detailed understanding of the degradation process will provide essential knowledge about the stability of the Pol I complex and benefit therapeutic implementation of Pol I inhibitory strategies.

To identify the E3 ligases involved, we conducted a cell-based RNAi screen for ubiquitin pathway genes associated with RPA194 degradation. This screen identified a Skp-Cullin-F-box (SCF) complex as a promising candidate E3 ligase. We focused on validating the role of the identified F-box protein, FBXL14, in RPA194 degradation. To do this, we conducted knockout, knockdown, and overexpression analyses of FBXL14 in melanoma, osteosarcoma, breast cancer and chronic myelogenous leukemia cancer cell lines. We show here that both the basal expression of RPA194 and the BMH-21-induced degradation depend on FBXL14. The expression of FBXL14 significantly affected the half-life of RPA194. Knockdown of FBXL14 increases RPA194 turnover upon BMH-21 treatment, while its overexpression reduces RPA194 half-life. Using co-immunoprecipitation analyses, we demonstrate that FBXL14 interacts with RPA194 both in cell lines and in vitro. To investigate the correlation between RPA194 degradation and cell death, we analyzed how the expression of FBXL14 affects sensitivity to BMH-21 using cell growth, viability, and colony formation assays. We found that FBXL14 overexpression increased the sensitivity to the drug. Our results have revealed novel regulatory aspects of Pol I, showing that the stability of the catalytic subunit is controlled by the F-box protein FBXL14. We discuss the implications of these findings on Pol I transcription activity and its regulation.

Citation Format: Stephanie Pitts, Hester Liu, Wenjun Fan, Brittany Ford, Ronald Hay, Marikki Laiho. Identification of an E3 ligase regulating the catalytic subunit of RNA polymerase I [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 678.

Widespread genetic heterogeneity of human ribosomal RNA genes

Polymorphism drives survival under stress and provides adaptability. Genetic polymorphism of ribosomal RNA (rRNA) genes derives from internal repeat variation of this multicopy gene, and from interindividual variation. A considerable amount of rRNA sequence heterogeneity has been proposed but has been challenging to estimate given the scarcity of accurate reference sequences. We identified four rDNA copies on chromosome 21 (GRCh38) with 99% similarity to recently introduced reference sequence KY962518.1. We customized a GATK bioinformatics pipeline using the four rDNA loci, spanning a total 145 kb, for variant calling and used high-coverage whole-genome sequencing (WGS) data from the 1000 Genomes Project to analyze variants in 2504 individuals from 26 populations. We identified a total of 3791 variant positions. The variants positioned nonrandomly on the rRNA gene. Invariant regions included the promoter, early 5' ETS, most of 18S, 5.8S, ITS1, and large areas of the intragenic spacer. A total of 470 variant positions were observed on 28S rRNA. The majority of the 28S rRNA variants were located on highly flexible human-expanded rRNA helical folds ES7L and ES27L, suggesting that these represent positions of diversity and are potentially under continuous evolution. Several variants were validated based on RNA-seq analyses. Population analyses showed remarkable ancestry-linked genetic variance and the presence of both high penetrance and frequent variants in the 5' ETS, ITS2, and 28S regions segregating according to the continental populations. These findings provide a genetic view of rRNA gene array heterogeneity and raise the need to functionally assess how the 28S rRNA variants affect ribosome functions.

Alterations in the Global Proteome and Phosphoproteome in Third Generation EGFR TKI Resistance Reveal Drug Targets to Circumvent Resistance

Lung cancer is the leading cause of cancer mortality worldwide. The treatment of patients with lung cancer harboring mutant EGFR with orally administered EGFR tyrosine kinase inhibitors (TKI) has been a paradigm shift. Osimertinib and rociletinib are third-generation irreversible EGFR TKIs targeting the EGFR T790M mutation. Osimertinib is the current standard of care for patients with EGFR mutations due to increased efficacy, lower side effects, and enhanced brain penetrance. Unfortunately, all patients develop resistance. Genomic approaches have primarily been used to interrogate resistance mechanisms. Here we characterized the proteome and phosphoproteome of a series of isogenic EGFR-mutant lung adenocarcinoma cell lines that are either sensitive or resistant to these drugs, comprising the most comprehensive proteomic dataset resource to date to investigate third generation EGFR TKI resistance in lung adenocarcinoma. Unbiased global quantitative mass spectrometry uncovered alterations in signaling pathways, revealed a proteomic signature of epithelial-mesenchymal transition, and identified kinases and phosphatases with altered expression and phosphorylation in TKI-resistant cells. Decreased tyrosine phosphorylation of key sites in the phosphatase SHP2 suggests its inhibition, resulting in subsequent inhibition of RAS/MAPK and activation of PI3K/AKT pathways. Anticorrelation analyses of this phosphoproteomic dataset with published drug-induced P100 phosphoproteomic datasets from the Library of Integrated Network-Based Cellular Signatures program predicted drugs with the potential to overcome EGFR TKI resistance. The PI3K/MTOR inhibitor dactolisib in combination with osimertinib overcame resistance both in vitro and in vivo. Taken together, this study reveals global proteomic alterations upon third generation EGFR TKI resistance and highlights potential novel approaches to overcome resistance. SIGNIFICANCE: Global quantitative proteomics reveals changes in the proteome and phosphoproteome in lung cancer cells resistant to third generation EGFR TKIs, identifying the PI3K/mTOR inhibitor dactolisib as a potential approach to overcome resistance.

Genetic Consequences of the Transatlantic Slave Trade in the Americas

According to historical records of transatlantic slavery, traders forcibly deported an estimated 12.5 million people from ports along the Atlantic coastline of Africa between the 16th and 19th centuries, with global impacts reaching to the present day, more than a century and a half after slavery's abolition. Such records have fueled a broad understanding of the forced migration from Africa to the Americas yet remain underexplored in concert with genetic data. Here, we analyzed genotype array data from 50,281 research participants, which-combined with historical shipping documents-illustrate that the current genetic landscape of the Americas is largely concordant with expectations derived from documentation of slave voyages. For instance, genetic connections between people in slave trading regions of Africa and disembarkation regions of the Americas generally mirror the proportion of individuals forcibly moved between those regions. While some discordances can be explained by additional records of deportations within the Americas, other discordances yield insights into variable survival rates and timing of arrival of enslaved people from specific regions of Africa. Furthermore, the greater contribution of African women to the gene pool compared to African men varies across the Americas, consistent with literature documenting regional differences in slavery practices. This investigation of the transatlantic slave trade, which is broad in scope in terms of both datasets and analyses, establishes genetic links between individuals in the Americas and populations across Atlantic Africa, yielding a more comprehensive understanding of the African roots of peoples of the Americas.

The Michigan Appropriateness Guide for Intravenous Catheters in Pediatrics: miniMAGIC

OBJECTIVES

Vascular access device decision-making for pediatric patients remains a complex, highly variable process. To date, evidence-based criteria to inform these choices do not exist. The objective of the Michigan Appropriateness Guide for Intravenous Catheters in pediatrics (miniMAGIC) was to provide guidance on device selection, device characteristics, and insertion technique for clinicians, balancing and contextualizing evidence with current practice through a multidisciplinary panel of experts.

METHODS

The RAND Corporation and University of California, Los Angeles Appropriateness Method was used to develop miniMAGIC, which included the following sequential phases: definition of scope and key terms, information synthesis and literature review, expert multidisciplinary panel selection and engagement, case scenario development, and appropriateness ratings by an expert panel via 2 rounds.

RESULTS

The appropriateness of the selection, characteristics, and insertion technique of intravenous catheters commonly used in pediatric health care across age populations (neonates, infants, children, and adolescents), settings, diagnoses, clinical indications, insertion locations, and vessel visualization devices and techniques was defined. Core concepts including vessel preservation, insertion and postinsertion harm minimization (eg, infection, thrombosis), undisrupted treatment provision, and inclusion of patient preferences were emphasized.

CONCLUSIONS

In this study, we provide evidence-based criteria for intravenous catheter selection (from umbilical catheters to totally implanted venous devices) in pediatric patients across a range of clinical indications. miniMAGIC also highlights core vascular access practices in need of collaborative research and innovation.

Network influences on policy implementation: Evidence from a global health treaty

This paper examines whether country implementation of a public health treaty is influenced by the implementation behaviors of other countries to which they have network ties. We examine implementation of the Framework Convention on Tobacco Control (FCTC) adopted by the World Health Organization in 2003 and ratified by approximately 94% of countries as of 2016. We constructed five networks: (1) geographic distance, (2) general trade, (3) tobacco trade, (4) GLOBALink referrals, and (5) GLOBALink co-subscriptions. Network exposure terms were constructed from these networks based on the implementation scores for six articles of the FCTC treaty. We estimate effects using a lagged Type 1 Tobit model. Results show that network effects were significant: (a) across all networks for article 6 (pricing and taxation), (b) distance, general trade, GL referrals, and GL co-subscriptions for article 8 (second hand smoke), (c) distance, general trade, and GL co-subscriptions for article 11 (packaging and labeling), and (d) distance and GL co-subscription for article 13 (promotion and advertising), (e) tobacco trade and GL co-subscriptions for article 14 (cessation). These results indicate that diffusion effects were more prevalent for pricing and taxation as well as restrictions on smoking in public places and packaging and labeling. These results suggest that network influences are possible in domains that are amenable to control by national governments but unlikely to occur in domains established by existing regulatory systems. Implications for future studies of policy implementation are discussed.

Genomic profiling of multiple sequentially acquired tumor metastatic sites from an "exceptional responder" lung adenocarcinoma patient reveals extensive genomic heterogeneity and novel somatic variants driving treatment response

We used next-generation sequencing to identify somatic alterations in multiple metastatic sites from an “exceptional responder” lung adenocarcinoma patient during his 7-yr course of ERBB2-directed therapies. The degree of heterogeneity was unprecedented, with ∼1% similarity between somatic alterations of the lung and lymph nodes. One novel translocation, PLAG1-ACTA2, present in both sites, up-regulated ACTA2 expression. ERBB2, the predominant driver oncogene, was amplified in both sites, more pronounced in the lung, and harbored an L869R mutation in the lymph node. Functional studies showed increased proliferation, migration, metastasis, and resistance to ERBB2-directed therapy because of L869R mutation and increased migration because of ACTA2 overexpression. Within the lung, a nonfunctional CDK12, due to a novel G879V mutation, correlated with down-regulation of DNA damage response genes, causing genomic instability, and sensitivity to chemotherapy. We propose a model whereby a subclone metastasized early from the primary site and evolved independently in lymph nodes.

Quantitative Tyrosine Phosphoproteomics of Epidermal Growth Factor Receptor (EGFR) Tyrosine Kinase Inhibitor-treated Lung Adenocarcinoma Cells Reveals Potential Novel Biomarkers of Therapeutic Response

Mutations in the Epidermal growth factor receptor (EGFR) kinase domain, such as the L858R missense mutation and deletions spanning the conserved sequence ⁷⁴⁷LREA⁷⁵⁰, are sensitive to tyrosine kinase inhibitors (TKIs). The gatekeeper site residue mutation, T790M accounts for around 60% of acquired resistance to EGFR TKIs. The first generation EGFR TKIs, erlotinib and gefitinib, and the second generation inhibitor, afatinib are FDA approved for initial treatment of EGFR mutated lung adenocarcinoma. The predominant biomarker of EGFR TKI responsiveness is the presence of EGFR TKI-sensitizing mutations. However, 30-40% of patients with EGFR mutations exhibit primary resistance to these TKIs, underscoring the unmet need of identifying additional biomarkers of treatment response. Here, we sought to characterize the dynamics of tyrosine phosphorylation upon EGFR TKI treatment of mutant EGFR-driven human lung adenocarcinoma cell lines with varying sensitivity to EGFR TKIs, erlotinib and afatinib. We employed stable isotope labeling with amino acids in cell culture (SILAC)-based quantitative mass spectrometry to identify and quantify tyrosine phosphorylated peptides. The proportion of tyrosine phosphorylated sites that had reduced phosphorylation upon erlotinib or afatinib treatment correlated with the degree of TKI-sensitivity. Afatinib, an irreversible EGFR TKI, more effectively inhibited tyrosine phosphorylation of a majority of the substrates. The phosphosites with phosphorylation SILAC ratios that correlated with the TKI-sensitivity of the cell lines include sites on kinases, such as EGFR-Y1197 and MAPK7-Y221, and adaptor proteins, such as SHC1-Y349/350, ERRFI1-Y394, GAB1-Y689, STAT5A-Y694, DLG3-Y705, and DAPP1-Y139, suggesting these are potential biomarkers of TKI sensitivity. DAPP1, is a novel target of mutant EGFR signaling and Y-139 is the major site of DAPP1 tyrosine phosphorylation. We also uncovered several off-target effects of these TKIs, such as MST1R-Y1238/Y1239 and MET-Y1252/1253. This study provides unique insight into the TKI-mediated modulation of mutant EGFR signaling, which can be applied to the development of biomarkers of EGFR TKI response.

Retrospective Analysis of a Pediatric Vascular Access Program and Clinical Outcomes

Background: The specialty of pediatric vascular access has grown rapidly during the past 5 years across the United States. The majority of children's hospitals have nurse-led vascular access teams that are providing comprehensive services, including the placement of peripherally inserted central catheters. A children's hospital in the southeastern United States conducted an Internal Review Board approved, retrospective analysis of 669 patients who had a peripherally inserted central catheter placed.

Objective: The objective was to have a better understanding of the program and clinical outcomes as well as identify areas for improvement.

Methods: A data collection tool was developed to review the medical records of patients receiving a peripherally inserted central catheter from January 2009 through June 2011. Variables of interest included patient age, admitting diagnosis, intended therapy, procedure location, sedation type and usage, procedure success, insertion attempts, vessel selected, catheter size and type, catheter tip location, reason for discontinuation, and infection. The data was collected and analyzed by a nurse researcher from the University of South Florida.

Results: Using the Modified Seldinger Technique and ultrasound, the team inserted a full line of polyurethane catheters, including computed tomography-injectable catheters, with an insertion success rate of 94%. We identified a significant reduction in our hospital's infection rate—from 9.12 per 1,000 catheter line days to 2.0 per 1,000 catheter line days—during the first year and a half of the program. The use of sedation and anesthesia was significantly reduced, with 49% of patients receiving an oral anxiolytic dose of midazolam and the integration of certified child life specialists into the procedure.

Conclusions: Pediatric vascular access is a rapidly growing specialty in nursing. Nurse-led vascular access teams have become commonplace in children's hospitals throughout the United States. Although the specialty has grown rapidly during the past 5 years, there is a need for data sharing to contribute to the knowledge base of pediatric vascular access.

Magnetic resonance profiling of human skin in vivo using GARField magnets

It is shown that one-dimensional magnetic resonance imaging (MRI-profiling) of human forearm and side-of-hand skin in vivo is possible using GARField magnets. Strong profile contrast originating from differing molecular mobility is seen for stratum corneum and viable epidermis. The first in vivo spatially-resolved field-gradient measurements of water self-diffusivity, D, in the stratum corneum (2.0 x 10(-6) cm(2)/s) and viable epidermis (8.5 x 10(-6) cm(2)/s) are reported. Also reported are spatially resolved measurements of the (1)H spin-lattice relaxation time, T(1), the spin-spin relaxation time, T(2). It is further shown that the application of moisturizing agents to the skin noticeably affects the profiles. However, universal behavior is not seen as both signal increases and decreases are observed dependent on agent and volunteer.

Steroid hormones during embryonic development in Japanese quail: plasma, gonadal, and adrenal levels

The purpose of this experiment was to measure plasma, gonad, and adrenal steroid hormones during embryonic and early posthatch development in Japanese quail. Blood plasma samples were collected from male and female Japanese quail embryos at 2-d intervals between Day 10 of incubation and Day 5 posthatch. Gonads and adrenal glands were collected from a separate set of embryos at the same ages. Concentrations of androgen (testosterone and 5alpha-dihydrotestosterone) and 17beta-estradiol (E2) were determined by RIA. Plasma androgen changed significantly (P < 0.001) with age in males and females, and there were significant differences (P < 0.001) between sexes in the hormonal patterns. Males had higher plasma androgen than females; conversely, females consistently had overall higher levels of estradiol than males. Adrenal gland steroid content remained relatively high and did not change significantly with age. In contrast, steroid content of gonads followed patterns similar to those observed for plasma levels. These results provide evidence for steroid hormone production by the gonads of both sexes, as well as for distinct differences in the patterns observed in the adrenal gland and gonads. These results provide evidence for gonadal regulation of changes in circulating hormone levels. Further, these hormonal patterns were associated with the timing of steroid-induced sexual differentiation in the Japanese quail, suggesting that plasma gonadal steroids are critical in sexual differentiation.

Changes in regional fat redistribution and the effects of estrogen during spontaneous weight gain in women with anorexia nervosa

BACKGROUND

Anorexia nervosa is a disease of severe acquired undernutrition with a high and increasing prevalence among young women in the United States.

OBJECTIVE

The objective was to investigate the effects of spontaneous outpatient weight recovery and estrogen administration on fat distribution in patients with anorexia nervosa.

DESIGN

Twenty-seven amenorrheic women aged 26.6 +/- 1.2 y with anorexia nervosa were identified through an outpatient study of bone loss and were randomly assigned to receive or not receive estrogen without any dietary intervention other than calcium and multivitamin supplements. Body composition was measured at baseline and at 6 and 9 mo and was compared with cross-sectional values obtained in 20 healthy, eumenorrheic, age-matched (25.4 +/- 0.5 y) control subjects.

RESULTS

Twenty of the 27 patients with anorexia aged 27.0 +/- 1.3 y spontaneously gained weight (4.1 +/- 0.9 kg); body mass index (in kg/m(2)) increased from 16.1 +/- 0.3 to 17.5 +/- 0.4. Fat mass and lean mass accounted for 68% and 32% of the gain in total body mass, respectively. With spontaneous weight gain, there was a significant increase in the percentage of trunk fat from 32.4 +/- 1.3% at baseline to 36.5 +/- 1.0% at 9 mo (P = 0.03), which correlated with urinary free cortisol (r = 0.66, P = 0.003). Estrogen treatment was not protective against the gain in trunk fat with spontaneous weight gain.

CONCLUSIONS

In women with anorexia nervosa, spontaneous weight gain is associated with a significant increase in trunk adiposity, and estrogen administration may not protect against the accumulation of central fat with weight gain.

Prevalence and predictive factors for regional osteopenia in women with anorexia nervosa

BACKGROUND

Anorexia nervosa is highly prevalent among young women.

OBJECTIVE

To determine prevalence and predictive factors for regional bone loss.

DESIGN

Prospective cohort analysis.

SETTING

University hospital.

PATIENTS

130 women with anorexia nervosa.

MEASUREMENTS

Dual-energy x-ray absorptiometry.

RESULTS

The prevalence of osteopenia (-1.0 SD >/= T-score > -2.5 SD) and osteoporosis (T-score </= -2.5 SD) was 50% and 13% for the anterior-posterior spine, 57% and 24% for the lateral spine, and 47% and 16% for the total hip, respectively. Bone mineral density (BMD) was reduced by at least 1.0 SD at one or more skeletal sites in 92% of patients and by at least 2.5 SD in 38% of patients. Weight was the most consistent predictor of BMD at all skeletal sites. Twenty-three percent of patients were current estrogen users, and 58% were previous estrogen users. Bone mineral density did not differ by history of estrogen use at any site.

CONCLUSIONS

Bone mineral density is reduced at several skeletal sites in most women with anorexia nervosa. Weight, but not estrogen use, is a significant predictor of BMD in this population at all skeletal sites.

Severity of osteopenia in estrogen-deficient women with anorexia nervosa and hypothalamic amenorrhea

Reduced bone density is observed in over half of women with anorexia nervosa (AN), in whom the risk of fracture is significantly increased even at a young age. It is unknown to what extent low bone density in AN differs from other conditions of premenopausal osteoporosis and is related to estrogen deficiency and/or other factors, such as nutritional status. We therefore investigated bone loss in nutritionally replete and nutritionally deplete amenorrheic women by comparing patients with AN (n = 30) to age-matched subjects with hypothalamic amenorrhea (HA; n = 19) in whom duration of amenorrhea, prior estrogen use, and age of menarche were comparable. Healthy, age-matched, eumenorrheic women were studied as a control group (NL; n = 30). Weight and nutritionally dependent factors including (body mass index, 20.7 +/- 0.3 vs. 16.7 +/- 0.3 kg/m2; P < 0.0001), insulin-like growth factor I (270 +/- 18 vs. 203 +/- 17 ng/mL; P < 0.01), percent body fat (26% vs. 19%; P < 0.0001), and lean body mass (38.7 +/- 1.1 vs. 34.3 +/- 0.8, P < 0.01) were significantly different between the HA and AN groups, respectively. The bone densities of the anterior-posterior (AP) spine, total hip, and total body measured by dual energy x-ray absortiometry were reduced in both amenorrheic groups compared to those in control subjects, but were significantly lower in women with AN than in those with HA. The t scores for AP spine and hip were -1.80 +/- 0.15 (AN), -0.80 +/- 0.22 (HA), and 0.28 +/- 0.19 SD (NL) for the AP spine and -1.62 +/- 0.17 (AN), -0.51 +/- 0.21 (HA), and 0.25 +/- 0.16 (NL) for the total hip, respectively (P < 0.01 for all comparisons). Among the amenorrheic subjects, duration of amenorrhea, age of menarche, and N-telopeptide were inversely correlated with bone density at all sites, whereas body mass index, insulin-like growth factor I, lean body mass, and fat intake were positively correlated with bone density at all sites measured. In multivariate regression analyses, bone density was most significantly related to lean body mass (P = 0.05 and P = 0.03 for the spine and hip, respectively), but not to the duration of amenorrhea or other indexes of estrogen status among patients with AN. In contrast, bone density of the lumbar spine was significantly related to weight and duration of amenorrhea among patients with HA. These data demonstrate that the severity of osteopenia in AN is greater than that in patients with HA and is critically dependent upon nutritional factors in addition to the degree or duration of estrogen deficiency itself. Lean body mass, independent of the duration or severity of estrogen deficiency, is an important predictor of bone loss among women with AN.

External validation of the Ottawa knee rules in an urban trauma center in the United States

OBJECTIVE

We evaluated the Ottawa knee rules in a high-volume teaching hospital in the United States to determine whether the rules could be safely used to decide whether patients with acute blunt knee trauma should undergo radiography.

SUBJECTS AND METHODS

During a 13-month period, 378 patients with acute blunt knee trauma were prospectively examined using the Ottawa knee rules. Data collected included the presence or absence of fracture predictors and the results of radiography.

RESULTS

A fracture was seen in 43 (11%) of the 378 patients who met inclusion criteria. The knee rules predicted 42 of the 43 fractures; sensitivity was 98%, and specificity was 19%. Radiography of 65 patients (17%) who had no predictors for fracture could have been avoided if the knee rules had been used to screen for radiography.

CONCLUSION

The Ottawa knee rules are highly sensitive for fracture in this setting and may safely be used to decide whether patients with acute blunt knee trauma should undergo radiography.

Heinz dilemma? Let the subject choose!

This description of a novel approach for studying the validity of Kohlberg's sequential and hierarchical theory of moral development involved 138 boys and 113 girls (14 to 18 years old) choosing a solution among 12 to Kohlberg's Heinz dilemma instead of being assigned one by an interviewer. The results were not supportive of the theory. The methodology of research on moral development needs to be examined.

Human purine nucleoside phosphorylase and adenosine deaminase: gene transfer into cultured cells and murine hematopoietic stem cells by using recombinant amphotropic retroviruses

Cell lines were established which produced high titers (approximately 10(6) infectious units per ml) of amphotropic, replication-defective recombinant retroviruses which transduced sequences encoding either human purine nucleoside phosphorylase (PNP) or adenosine deaminase (ADA). These viruses also contained a human hypoxanthine phosphoribosyltransferase gene as a selectable marker and a mouse metallothionein promoter (MMP) sequence just upstream from the PNP or ADA genes. Virus structure was maintained through the replication cycle if a short (216-base pair) MMP sequence was used. However, the use of a longer (1,834-base pair) MMP sequence resulted in the deletion of a significant portion of the recombinant virus genome, including the transcriptional regulatory elements of the MMP sequence. Northern analysis indicated a predominance of genome length transcripts in cells infected with deleted virus. The demonstration of substantial human PNP or ADA activity in virus-infected mouse fibroblasts by isozyme analysis suggested that active gene product was translated from either spliced or bicistronic message. The deleted ADA and PNP viruses were introduced into mouse hematopoietic stem cells by cocultivating freshly explanted bone marrow with virus producer cells. The infected marrow cells were injected into irradiated, syngeneic recipient mice, and the presence of integrated ADA or PNP proviral sequences was demonstrated in the DNA of spleen colonies by Southern analysis. Failure of these integrated proviral sequences to express active, human isozyme in spleen colony tissue indicated the existence of some regulatory constraint not active in cultured mouse cells.