Endothelial SMAD1/5 signaling couples angiogenesis to osteogenesis in juvenile bone

Skeletal development depends on coordinated angiogenesis and osteogenesis. Bone morphogenetic proteins direct bone formation in part by activating SMAD1/5 signaling in osteoblasts. However, the role of SMAD1/5 in skeletal endothelium is unknown. Here, we found that endothelial cell-conditional SMAD1/5 depletion in juvenile mice caused metaphyseal and diaphyseal hypervascularity, resulting in altered trabecular and cortical bone formation. SMAD1/5 depletion induced excessive sprouting and disrupting the morphology of the metaphyseal vessels, with impaired anastomotic loop formation at the chondro-osseous junction. Endothelial SMAD1/5 depletion impaired growth plate resorption and, upon long-term depletion, abrogated osteoprogenitor recruitment to the primary spongiosa. Finally, in the diaphysis, endothelial SMAD1/5 activity was necessary to maintain the sinusoidal phenotype, with SMAD1/5 depletion inducing formation of large vascular loops and elevated vascular permeability. Together, endothelial SMAD1/5 activity sustains skeletal vascular morphogenesis and function and coordinates growth plate remodeling and osteoprogenitor recruitment dynamics in juvenile mouse bone.

YAP and TAZ couple osteoblast precursor mobilization to angiogenesis and mechanoregulation in murine bone development

Fetal bone development occurs through the conversion of avascular cartilage to vascularized bone at the growth plate. This requires coordinated mobilization of osteoblast precursors with blood vessels. In adult bone, vessel-adjacent osteoblast precursors are maintained by mechanical stimuli; however, the mechanisms by which these cells mobilize and respond to mechanical cues during embryonic development are unknown. Here, we show that the mechanoresponsive transcriptional regulators Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) spatially couple osteoblast precursor mobilization to angiogenesis, regulate vascular morphogenesis to control cartilage remodeling, and mediate mechanoregulation of embryonic murine osteogenesis. Mechanistically, YAP and TAZ regulate a subset of osteoblast-lineage cells, identified by single-cell RNA sequencing as vessel-associated osteoblast precursors, which regulate transcriptional programs that direct blood vessel invasion through collagen-integrin interactions and Cxcl12. Functionally, in 3D human cell co-culture, CXCL12 treatment rescues angiogenesis impaired by stromal cell YAP/TAZ depletion. Together, these data establish functions of the vessel-associated osteoblast precursors in bone development.

Quantitative analysis of the UDP-glucuronosyltransferase transcriptome in human tissues

UDP-glucuronosyltransferases (UGTs) are phase II drug metabolizing enzymes that play important roles in the detoxification of endogenous and exogenous substrates. The 22 human UGTs belong to four families (UGT1, UGT2, UGT3, and UGT8) and differ in their expression, substrate specificity, UDP-sugar preference, and physiological functions. Differential expression/activity of the UGTs contributes to interperson variability in drug responses and toxicity, hormone homeostasis, and disease/cancer risks. However, in normal tissues, the tissue-specific expression profiles and transcriptional regulation of the UGTs are still not fully understood. In this study, we comprehensively analyzed the transcriptome of 22 UGTs in 54 human tissues/regions using RNAseq data from GTEx. We then validated the findings in the liver and small intestine samples using real-time PCR. Our results showed large interindividual variability across tissues in the expression of each UGT and the overall composition of UGT pools, consisting of different UGTs and their splice isoforms. Our results also revealed coexpression of the UGTs, Cytochrome P450s, and many transcription factors in the liver, suggesting potential coregulation or functional coordination. Our results provide the groundwork for future studies to detail further the regulation of the expression and activity of the UGTs.

A Comprehensive Evaluation of the Effects of RNA-Editing Proteins ADAR and ADARB1 on the Expression of the Drug-Metabolizing Enzymes in HepaRG Cells

Two RNA-editing proteins, the adenosine deaminase acting on RNA, ADAR, and ADARB1, broadly regulate gene expression in editing-dependent and editing-independent manners. Previous studies showed that the expression of the drug-metabolizing cytochrome P450s (P450s) and UDP glucuronosyltransferases (UGTs) changes upon knockdown (KD) of ADAR or ADARB1 in different hepatic cell lines. To systematically survey the effects of these two ADARs on the expression of P450s and UGTs, we used small interfering RNA in HepaRG cells and tested the association between the expression of the P450s and ADARs in a liver sample cohort (n = 246). KD of ADAR increased the expression of the CYP3As and CYP2C9 and reduced the expression of the others, whereas KD of ADARB1 reduced the expression of nearly all genes tested. ADAR KD also suppressed the induction of most P450s, whereas ADARB1 KD had mixed effects depending on the inducer/gene combination. P450 expression was positively associated with both ADARs in liver samples, consistent with the KD results. However, after adjusting for the expression of transcription factors (TFs) known to regulate P450 expression, the associations disappeared, indicating that the effects of ADAR or ADARB1 primarily occur through TFs. Moreover, we found that the expression of normally spliced CYP3A5 transcripts is increased in both KDs, indicating a direct effect of the ADARs on promoting the usage of the cryptic splice site generated by CYP3A5*3. Taken together, our results revealed the nonoverlapping regulatory effects of ADAR and ADARB1 and supported their broad roles in controlling the expression of drug-metabolizing enzymes in the liver. SIGNIFICANCE STATEMENT: Here, this study systematically surveyed the roles of ADAR and ADARB1 in both basal and induced expression of drug-metabolizing enzymes and assessed their coexpression in liver samples. This study's results support that ADAR and ADARB1 regulate the expression of the drug-metabolizing enzymes in the liver, suggesting that factors affecting ADAR expression also have the potential to impact drug metabolism.

A frequent CYP2D6 variant promotes skipping of exon 3 and reduces CYP2D6 protein expression in human liver samples

CYP2D6 is one of the most polymorphic drug-metabolizing enzymes in the liver. While genetic CYP2D6 variants serve as clinical biomarkers to predict CYP2D6 activity, large inter-person variability in CYP2D6 expression remains unaccounted for. Previous results suggest that there is variable expression of a CYP2D6 splice isoform with an in-frame deletion of exon 3 (CYP2D6ΔE3) encoding a protein lacking numerous active site residues. Here, using fragment analysis and RT-qPCR, we revealed that rs1058164 G (MAF = 27%-43%) is associated with increased formation of CYP2D6∆E3 in human liver samples (1.4-2.5-fold) and transfected cells. Furthermore, western blots showed that rs1058164 G was associated with a 50% decrease in full-length hepatic CYP2D6 protein expression. In addition, by studying a larger liver cohort, we confirmed our previous results that rs16947 (CYP2D6*2) reduces full-length CYP2D6 mRNA by increasing the production of an unstable splice isoform lacking exon 6 (CYP2D6ΔE6) and that the impact of CYP2D6ΔE6 is offset in carriers of the downstream enhancer variant rs5758550. The three frequent SNPs (rs1058164, rs16947, and rs5758550) form various 3-SNP-haplotypes, each with distinct CYP2D6 expression characteristics. Using an expression score (ES) system, we tested the impact of the 3-SNP-haplotype on improving the standard model to predict hepatic CYP2D6 protein expression based on genotype. A model that incorporates the 3-SNP-haplotype provided the best fit for CYP2D6 expression and also accounted for more variability in CYP2D6 protein levels (59%) than a model based on the accepted standard (36%) or one that only adds rs16947 and rs5758550 (42%). Clinical studies are needed to determine whether including the 3-SNP-haplotype alongside current standard CYP2D6 models improves the predictive value of CYP2D6 panels.

YAP and TAZ couple osteoblast precursor mobilization to angiogenesis and mechanoregulated bone development

Endochondral ossification requires coordinated mobilization of osteoblast precursors with blood vessels. During adult bone homeostasis, vessel adjacent osteoblast precursors respond to and are maintained by mechanical stimuli; however, the mechanisms by which these cells mobilize and respond to mechanical cues during embryonic development are unknown. Previously, we found that deletion of the mechanoresponsive transcriptional regulators, YAP and TAZ, from Osterix-expressing osteoblast precursors and their progeny caused perinatal lethality. Here, we show that embryonic YAP/TAZ signaling couples vessel-associated osteoblast precursor mobilization to angiogenesis in developing long bones. Osterix-conditional YAP/TAZ deletion impaired endochondral ossification in the primary ossification center but not intramembranous osteogenesis in the bone collar. Single-cell RNA sequencing revealed YAP/TAZ regulation of the angiogenic chemokine, Cxcl12, which was expressed uniquely in vessel-associated osteoblast precursors. YAP/TAZ signaling spatially coupled osteoblast precursors to blood vessels and regulated vascular morphogenesis and vessel barrier function. Further, YAP/TAZ signaling regulated vascular loop morphogenesis at the chondro-osseous junction to control hypertrophic growth plate remodeling. In human cells, mesenchymal stromal cell co-culture promoted 3D vascular network formation, which was impaired by stromal cell YAP/TAZ depletion, but rescued by recombinant CXCL12 treatment. Lastly, YAP and TAZ mediated mechanotransduction for load-induced osteogenesis in embryonic bone.

Regulatory variants in a novel distal enhancer regulate the expression of CYP3A4 and CYP3A5

The cytochrome P450 3As (CYP3As) are abundantly expressed in the liver and metabolize many commonly prescribed medications. Their expression is highly variable between individuals with little known genetic cause. Despite extensive investigation, cis-acting genetic elements that control the expression of the CYP3As remain uncharacterized. Using chromatin conformation capture (4C assays), we detected reciprocal interaction between a distal regulatory region (DRR) and the CYP3A4 promoter. The DRR colocalizes with a variety of enhancer marks and was found to promote transcription in reporter assays. CRISPR-mediated deletion of the DRR decreased expression of CYP3A4, CYP3A5, and CYP3A7, supporting its role as a shared enhancer regulating the expression of three CYP3A genes. Using reporter gene assays, we identified two single-nucleotide polymorphisms (rs115025140 and rs776744/rs776742) that increased DRR-driven luciferase reporter expression. In a liver cohort (n = 246), rs115025140 was associated with increased expression of CYP3A4 mRNA (1.8-fold) and protein (1.6-fold) and rs776744/rs776742 was associated with 1.39-fold increased expression of CYP3A5 mRNA. The rs115025140 is unique to the African population and in a clinical cohort of African Americans taking statins for lipid control rs115025140 carriers showed a trend toward reduced statin-mediated lipid reduction. In addition, using a published cohort of Chinese patients who underwent renal transplantation taking tacrolimus, rs776744/rs776742 carriers were associated with reduced tacrolimus concentration after adjusting for CYP3A5*3. Our results elucidate a complex regulatory network controlling expression of three CYP3A genes and identify two novel regulatory variants with potential clinical relevance for predicting CYP3A4 and CYP3A5 expression.

Genome-wide microRNA profiles identify miR-107 as a top miRNA associating with expression of the CYP3As and other drug metabolizing cytochrome P450 enzymes in the liver

Cytochrome P450 (CYP) drug metabolizing enzymes are responsible for the metabolism of over 70% of currently used medications with the CYP3A family being the most important CYP enzymes in the liver. Large inter-person variability in expression/activity of the CYP3As greatly affects drug exposure and treatment outcomes, yet the cause of such variability remains elusive. Micro-RNAs (miRNAs) are small noncoding RNAs that negatively regulate gene expression and are involved in diverse cellular processes including metabolism of xenobiotics and therapeutic outcomes. Target prediction and in vitro functional assays have linked several miRNAs to the control of CYP3A4 expression. Yet, their co-expression with CYP3As in the liver remain unclear. In this study, we used genome-wide miRNA profiling in liver samples to identify miRNAs associated with the expression of the CYP3As. We identified and validated both miR-107 and miR-1260 as strongly associated with the expression of CYP3A4, CYP3A5, and CYP3A43. Moreover, we found associations between miR-107 and nine transcription factors (TFs) that regulate CYP3A expression, with estrogen receptor alpha (ESR1) having the largest effect size. Including ESR1 and the other TFs in the regression model either diminished or abolished the associations between miR-107 and the CYP3As, indicating that the role of miR-107 in CYP3A expression may be indirect and occur through these key TFs. Indeed, testing the other nine CYPs previously shown to be regulated by ESR1 identified similar miR-107 associations that were dependent on the exclusion of ESR1 and other key TFs in the regression model. In addition, we found significant differences in miRNA expression profiles in liver samples between race and sex. Together, our results identify miR-107 as a potential epigenetic regulator that is strongly associated with the expression of many CYPs, likely via impacting the CYP regulatory network controlled by ESR1 and other key TFs. Therefore, both genetic and epigenetic factors that alter the expression of miR-107 may have a broad influence on drug metabolism.

Transcriptional Regulation of Carboxylesterase 1 in Human Liver: Role of the Nuclear Receptor Subfamily 1 Group H Member 3 and Its Splice Isoforms

Carboxylesterase 1 (CES1) is the predominant carboxylesterase in the human liver, involved in metabolism of both xenobiotics and endogenous substrates. Genetic or epigenetic factors that alter CES1 activity or expression are associated with changes in drug response, lipid, and glucose homeostasis. However, the transcriptional regulation of CES1 in the human liver remains uncertain. By applying both the random forest and Sobol's Sensitivity Indices (SSI) to analyze existing liver RNA expression microarray data (GSE9588), we identified nuclear receptor subfamily 1 group H member 3 (NR1H3) liver X receptor (LXR)α as a key factor regulating constitutive CES1 expression. This model prediction was validated using small interfering RNA (siRNA) knockdown and CRISPR-mediated transcriptional activation of NR1H3 in Huh7 and HepG2 cells. We found that NR1H3's activation of CES1 is splice isoform-specific, namely that increased expression of the NR1H3-211 isoform increased CES1 expression whereas NR1H3-201 did not. Also, in human liver samples, expression of NR1H3-211 and CES1 are correlated, whereas NR1H3-201 and CES1 are not. This trend also occurs during differentiation of induced pluripotent stem cells (iPSCs) to hepatocytes, where only expression of the NR1H3-211 isoform parallels expression of CES1 Moreover, we found that treatment with the NR1H3 agonist T0901317 in HepG2 cells had no effect on CES1 expression. Overall, our results demonstrate a key role of NR1H3 in maintaining the constitutive expression of CES1 in the human liver. Furthermore, our results support that the effect of NR1H3 is splice isoform-specific and appears to be ligand independent. SIGNIFICANCE STATEMENT: Despite the central role of carboxylesterase 1 (CES1) in metabolism of numerous medications, little is known about its transcriptional regulation. This study identifies nuclear receptor subfamily 1 group H member 3 as a key regulator of constitutive CES1 expression and therefore is a potential target for future studies to understand interperson variabilities in CES1 activity and drug metabolism.

Regulation of CYP3A4 and CYP3A5 by a lncRNA: a potential underlying mechanism explaining the association between CYP3A4*1G and CYP3A metabolism

The cytochrome P450 3A4 (CYP3A4) enzyme is the most abundant drug-metabolizing enzyme in the liver, displaying large inter-person variability with unknown causes. In this study, we found that the expression of CYP3A4 is negatively correlated with AC069294.1 (ENSG00000273407, ENST00000608397.1), a lncRNA generated antisense to CYP3A4. Knockdown of AC069294.1 in Huh7 cells increased CYP3A4 mRNA ~3-fold, whereas overexpression of AC069294.1 decreased CYP3A4 mRNA by 89%. We also observed changes in CYP3A5 expression when AC069294.1 was knocked down or overexpressed, indicating dual effects of AC069294.1 on both CYP3A4 and CYP3A5 expression. Consistently, the expression level of CYP3A5 is also negatively correlated with AC069294.1. Previous studies have shown associations between an intronic single nucleotide polymorphism CYP3A4*1G (rs2242480) and CYP3A metabolism, but the results are inconsistent and the underlying mechanism is unclear. We show here that CYP3A4*1G (rs2242480) is associated with 1.26-fold increased expression of AC069294.1 (P < 0.0001), and decreased expression of CYP3A4 by 31% (P = 0.008) and CYP3A5 by 39% (P = 0.004). CYP3A4*1G is located ~2.7 kb upstream of AC069294.1 and has been previously reported to have increased transcriptional activity in reporter gene assays. Taken together, our results demonstrate the regulation of CYP3A4 and CYP3A5 by a novel lncRNA AC069294.1. Our results also indicate that the clinically observed CYP3A4*1G associations may be caused by its effect on the expression of AC069294.1, and thereby altered expression of both CYP3A4 and CYP3A5. Furthermore, because CYP3A4*1G is in high linkage disequilibrium with CYP3A5*1, increased AC069294.1 expression caused by CYP3A4*1G may decrease expression of the normal-functioning CYP3A5*1, explaining additional inter-person variability of CYP3A5.

Review: Veratrum californicum Alkaloids

Veratrum spp. grow throughout the world and are especially prevalent in high mountain meadows of North America. All parts of Veratrum plants have been used for the treatment of ailments including injuries, hypertension, and rheumatic pain since as far back as the 1600s. Of the 17-45 Veratrum spp., Veratrum californicum alkaloids have been proven to possess favorable medicinal properties associated with inhibition of hedgehog (Hh) pathway signaling. Aberrant Hh signaling leads to proliferation of over 20 cancers, including basal cell carcinoma, prostate and colon among others. Six of the most well-studied V. californicum alkaloids are cyclopamine (1), veratramine (2), isorubijervine (3), muldamine (4), cycloposine (5), and veratrosine (6). Recent inspection of the ethanolic extract from V. californicum root and rhizome via liquid chromatography-mass spectrometry has detected up to five additional alkaloids that are proposed to be verazine (7), etioline (8), tetrahydrojervine (9), dihydrojervine (10), 22-keto-26-aminocholesterol (11). For each alkaloid identified or proposed in V. californicum, this review surveys literature precedents for extraction methods, isolation, identification, characterization and bioactivity to guide natural product drug discovery associated with this medicinal plant.

Instrumentation for Routine Analysis of Acrylamide in French Fries: Assessing Limitations for Adoption

The purpose of this experimental review was to detect acrylamide in French fries using methods most adaptable to the food process industry for quality control assessment of products. French fries were prepared at different cook times using the same fryer oil over a five-day period to assess the influence of oil degradation and monitor trends in acrylamide formation. Acrylamide detection was performed using LC-MS, GC-MS and FT-NIR. The low levels of acrylamide produced during frying, low molecular weight of the analyte, and complexity of the potato matrix make routine acrylamide measurement challenging in a well-outfitted analytical lab with trained personnel. The findings of this study are presented from the perspective of pros and cons of each acrylamide measurement method in enough detail for food processors to appraise the method that may work best for them based on their available instrumentation and extent of personnel training.

Cytochrome P450 3A4 (CYP3A4) protein quantification using capillary western blot technology and total protein normalization

The western blot (WB) is the predominate method for protein quantification, frequently used in pharmacological and toxicological studies. To control for technical variation, WB signals are normalized through immunodetection of an internal standard "house-keeping" gene or total protein quantification via staining of the same blot or a duplicate, sister blot. Increasing evidence suggests that house-keeping genes are subject to change after drug treatment or under disease states, causing protein quantification errors in WB. Recent advances in automated capillary-based WB technologies enable measurement of the protein of interest, internal standards, and total protein in a single capillary. Using this approach, we quantified cytochrome P450 3A4 (CYP3A4) across 179 liver samples and compared normalization by both β-actin and total protein to determine which better functions as an internal standard. CYP3A4 is responsible for metabolism of a wide array of xenobiotics and is known to exhibit large inter-person variation, making it a good candidate to evaluate protein quantification. We observed significant differences in β-actin protein levels between liver samples (~20-fold) and found better correlation between CYP3A4 protein and mRNA using total protein normalization than β-actin, indicating total protein normalization to be less error prone for estimation of CYP3A4. Furthermore, by using total protein normalization, we confirmed significant association between CYP3A4 protein expression and the functional CYP3A4 variant CYP3A4*22, which contains two linked SNPs rs35599367 and rs62471956. Our results indicate that the automatic capillary WB instrument combined with total protein normalization provides a high throughput and robust approach for protein quantification.

Clinical outcomes among patients with tuberculous meningitis receiving intensified treatment regimens

SETTING: National Center for Tuberculosis and Lung Diseases (NCTLD), Tbilisi, Georgia.OBJECTIVE: To determine clinical outcomes of patients with tuberculous meningitis (TBM) treated with an intensified regimen including a fluoroquinolone (FQ) and an injectable agent.DESIGN: Prospective cohort of patients aged ≥16 years initiating treatment for TBM at the NCTLD from January 2018 to December 2019. Treatment outcomes and neurologic disability at 1, 6 and 12 months after treatment initiation were assessed.RESULTS: Among 77 patients with median follow-up time of 363 days (IQR 269-374), 97% received a FQ, 62% an injectable agent, 44% linezolid and 39% a carbapenem. Fifty-seven patients (74%) successfully completed treatment, 2 (2.6%) had treatment failure, 6 (7.8%) died, and the remainder (12%) were lost to follow up. Among 11 patients treated for multidrug-resistant TBM, the median follow-up time was 467 days and one patient (8%) died. Regarding neurologic outcomes, 14/76 (18%) patients had Modified Rankin Scores of 0 at baseline, improving to 85% (56/66) and 94% (47/50) at 6 and 12 months, respectively.CONCLUSION: Intensified multidrug treatment regimens including a FQ and an injectable agent in all patients and newly implemented drugs in patients with multidrug-resistant TBM resulted in low mortality and favorable neurologic outcomes.

Co-expression of drug metabolizing cytochrome P450 enzymes and estrogen receptor alpha (ESR1) in human liver: racial differences and the regulatory role of ESR1

OBJECTIVES

The function and expression of cytochrome P450 (CYP) drug metabolizing enzymes is highly variable, greatly affecting drug exposure, and therapeutic outcomes. The expression of these enzymes is known to be controlled by many transcription factors (TFs), including ligand-free estrogen receptor alpha (ESR1, in the absence of estrogen). However, the relationship between the expression of ESR1, other TFs, and CYP enzymes in human liver is still unclear.

METHODS

Using real-time PCR, we quantified the mRNA levels of 12 CYP enzymes and nine TFs in 246 human liver samples from European American (EA, n = 133) and African American (AA, n = 113) donors.

RESULTS

Our results showed higher expression levels of ESR1 and six CYP enzymes in EA than in AA. Partial least square regression analysis showed that ESR1 is the top-ranking TF associating with the expression of eight CYP enzymes, six of which showed racial difference in expression. Conversely, four CYP enzymes without racial difference in expression did not have ESR1 as a top-ranking TF. These results indicate that ESR1 may contribute to variation in CYP enzyme expression between these two ancestral backgrounds.

CONCLUSIONS

These results are consistent with our previous study showing ESR1 as a master regulator for the expression of several CYP enzymes. Therefore, factors affecting ESR1 expression may have broad influence on drug metabolism through altered expression of CYP enzymes.

SIRT1 Gene SNP rs932658 Is Associated With Medication-Related Osteonecrosis of the Jaw

Medication-related osteonecrosis of the jaw (MRONJ) is a rare but serious adverse drug reaction. Our previous whole-exome sequencing study found SIRT1 intronic region single-nucleotide polymorphism (SNP) rs7896005 to be associated with MRONJ in cancer patients treated with intravenous (iv) bisphosphonates (BPs). This study aimed to identify causal variants for this association. In silico analyses identified three SNPs (rs3758391, rs932658, and rs2394443) in the SIRT1 promoter region that are in high linkage disequilibrium (r²  > 0.8) with rs7896005. To validate the association between these SNPs and MRONJ, we genotyped these three SNPs on the germline DNA from 104 cancer patients of European ancestry treated with iv BPs (46 cases and 58 controls). Multivariable logistic regression analysis showed the minor alleles of these three SNPs were associated with lower odds for MRONJ. The odds ratios (95% confidence interval) and p values were 0.351 (0.164-0.751; p = 0.007) for rs3758391, 0.351 (0.164-0.751; p = 0.007) for rs932658, and 0.331 (0.157-0.697; p = 0.0036) for rs2394443, respectively. In the reporter gene assays, constructs containing rs932658 with variant allele A had higher luciferase activity than the reference allele, whereas constructs containing SNP rs3758391 and/or rs2394443 did not significantly affect activity. These results indicate that the promoter SNP rs932658 regulates the expression of SIRT1 and presumably lowers the risk of MRONJ by increasing SIRT1 expression. © 2020 American Society for Bone and Mineral Research (ASBMR).

Gone Caving: Roles of the Transcriptional Regulators YAP and TAZ in Skeletal Development

PURPOSE OF REVIEW

The development of the skeleton is controlled by cellular decisions determined by the coordinated activation of multiple transcription factors. Recent evidence suggests that the transcriptional regulator proteins, Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ), could have important roles in directing the activity of these transcriptional programs. However, in vitro evidence for the roles of YAP and TAZ in skeletal cells has been hopelessly contradictory. The goals of this review are to provide a cross-sectional view on the state of the field and to synthesize the available data toward a unified perspective.

RECENT FINDINGS

YAP and TAZ are regulated by diverse upstream signals and interact downstream with multiple transcription factors involved in skeletal development, positioning YAP and TAZ as important signal integration nodes in an hourglass-shaped signaling pathway. Here, we provide a survey of putative transcriptional co-effectors for YAP and TAZ in skeletal cells. Synthesizing the in vitro data, we conclude that TAZ is consistently pro-osteogenic in function, while YAP can exhibit either pro- or anti-osteogenic activity depending on cell type and context. Synthesizing the in vivo data, we conclude that YAP and TAZ combinatorially promote developmental bone formation, bone matrix homeostasis, and endochondral fracture repair by regulating a variety of transcriptional programs depending on developmental stage. Here, we discuss the current understanding of the roles of the transcriptional regulators YAP and TAZ in skeletal development, and provide recommendations for continued study of molecular mechanisms, mechanotransduction, and therapeutic implications for skeletal disease.

Recapitulating bone development through engineered mesenchymal condensations and mechanical cues for tissue regeneration

Large bone defects cannot form a callus and exhibit high complication rates even with the best treatment strategies available. Tissue engineering approaches often use scaffolds designed to match the properties of mature bone. However, natural fracture healing is most efficient when it recapitulates development, forming bone via a cartilage intermediate (endochondral ossification). Because mechanical forces are critical for proper endochondral bone development and fracture repair, we hypothesized that recapitulating developmental mechanical forces would be essential for large bone defect regeneration in rats. Here, we engineered mesenchymal condensations that mimic the cellular organization and lineage progression of the early limb bud in response to local transforming growth factor-β1 presentation from incorporated gelatin microspheres. We then controlled mechanical loading in vivo by dynamically tuning fixator compliance. Mechanical loading enhanced mesenchymal condensation-induced endochondral bone formation in vivo, restoring functional bone properties when load initiation was delayed to week 4 after defect formation. Live cell transplantation produced zonal human cartilage and primary spongiosa mimetic of the native growth plate, whereas condensation devitalization before transplantation abrogated bone formation. Mechanical loading induced regeneration comparable to high-dose bone morphogenetic protein-2 delivery, but without heterotopic bone formation and with order-of-magnitude greater mechanosensitivity. In vitro, mechanical loading promoted chondrogenesis and up-regulated pericellular matrix deposition and angiogenic gene expression. In vivo, mechanical loading regulated cartilage formation and neovascular invasion, dependent on load timing. This study establishes mechanical cues as key regulators of endochondral bone defect regeneration and provides a paradigm for recapitulating developmental programs for tissue engineering.

Prevalence of pulmonary tuberculosis among students in three eastern Ethiopian universities

SETTINGS

Three universities located in eastern Ethiopia: Haramaya University, Haramaya; Dire-Dawa University, Dire-Dawa; and Jigjiga University, Jigjiga.

OBJECTIVE

To determine the burden of pulmonary tuberculosis (PTB) among university students and to identify risk factors for the development of TB disease.

DESIGN

All full-time university students were screened for symptoms of PTB and sputum was collected for acid-fast bacilli (AFB) examination and culture for Mycobacterium tuberculosis.

RESULTS

Of 35 344 students screened, we identified 153 PTB cases that occurred over the 1-year study period, or 433/100 000 students. Of these, 117 (76%) PTB cases were found through passive case finding at student health centres, while 36 (24%) previously undiagnosed patients were identified through active case finding. Sixteen cases detected using active case finding (44%) were smear-positive. Living in a dormitory with 5 students and attending university for 2 years were both significantly associated with PTB (adjusted OR 2.49 and 3.79, respectively, P < 0.001). In persons who underwent drug susceptibility testing, 11 (30.5%) had resistance to at least one first-line anti-tuberculosis drug.

CONCLUSION

We found a high burden of TB among university students in eastern Ethiopia. Screening for PTB upon university admission and at regular intervals should be considered to minimise TB transmission on university campuses.

Sister Mary Joseph Nodule in Advanced Pancreatic Adenocarcinoma Identified on 18F-FDG PET/MRI

Sister Mary Joseph nodule is an umbilical metastatic lesion typically originating from gastrointestinal or gynecologic malignancies. In pancreatic cancer, Sister Mary Joseph nodule is a sign of advanced disease with an associated poor prognosis. ¹⁸F-FDG PET/MRI provides an imaging tool in the identification of Sister Mary Joseph nodule and helps to improve the staging of pancreatic cancer.

YAP and TAZ limit cytoskeletal and focal adhesion maturation to enable persistent cell motility

The importance of transcription during cell motility is controversial. Mason et al. show that YAP/TAZ-mediated transcription is required to limit cytoskeletal tension generation and permit persistent cell motility. This pathway is defined as a negative feedback loop whereby Rho-ROCK-myosin activate YAP and TAZ, which limit myosin activation through NUAK2 expression.

Cell migration initiates by traction generation through reciprocal actomyosin tension and focal adhesion reinforcement, but continued motility requires adaptive cytoskeletal remodeling and adhesion release. Here, we asked whether de novo gene expression contributes to this cytoskeletal feedback. We found that global inhibition of transcription or translation does not impair initial cell polarization or migration initiation, but causes eventual migratory arrest through excessive cytoskeletal tension and over-maturation of focal adhesions, tethering cells to their matrix. The transcriptional coactivators YAP and TAZ mediate this feedback response, modulating cell mechanics by limiting cytoskeletal and focal adhesion maturation to enable persistent cell motility and 3D vasculogenesis. Motile arrest after YAP/TAZ ablation was partially rescued by depletion of the YAP/TAZ-dependent myosin phosphatase regulator, NUAK2, or by inhibition of Rho-ROCK-myosin II. Together, these data establish a transcriptional feedback axis necessary to maintain a responsive cytoskeletal equilibrium and persistent migration.

Highly Variable Expression of ESR1 Splice Variants in Human Liver: Implication in the Liver Gene Expression Regulation and Inter-Person Variability in Drug Metabolism and Liver Related Diseases

Estrogen receptor alpha (ESR1) plays an important role in many tissues including the liver. Numerous alternative splice variants of ESR1 exist that encode ESR1 proteins with varying functions. We aim to study ESR1 genomic organization and its mRNA expression profile in human liver by incorporating information from literature and genomic databases (Ensembl, NCBI and GTEx), and employing a quantitative method to measure all known ESR1 mRNA splice variants in 36 human livers. We re-constructed ESR1 genomic organization map that contains 29 exons. ESR1 mRNA splice variants with varying 5' untranslated region (5'UTR) and/or missing each of eight coding exons are readily detectable in liver and other tissues. Moreover, we found extensive inter-individual variability in splice variant pattern of ESR1 transcripts. Specifically, ESR1 transcripts lacking first coding exon are the main transcripts in liver, which encode ESR1 proteins missing N-terminal 173 amino acids (for example, ERα46), reported previously to have either constitutive activity or dominant negative effects depending on cellular context. Moreover, some livers predominantly express ESR1 transcripts missing exon 10 or 16, encoding C-terminal truncated ESR1 proteins with varying ESR1 activities. Inter-person variability in ESR1 expression profile may contribute to inter-person variability in drug metabolism and susceptibility to liver related diseases.

Utility of 18F-fluoroestradiol (18F-FES) PET/CT imaging as a pharmacodynamic marker in patients with refractory estrogen receptor-positive solid tumors receiving Z-endoxifen therapy

BACKGROUND

Z-endoxifen is the most potent of the metabolites of tamoxifen, and has the potential to be more effective than tamoxifen because it bypasses potential drug resistance mechanisms attributable to patient variability in the expression of the hepatic microsomal enzyme CYP2D6. ¹⁸F-FES is a positron emission tomography (PET) imaging agent which selectively binds to estrogen receptor alpha (ER-α) and has been used for non-invasive in vivo assessment of ER activity in tumors. This study utilizes ¹⁸F-FES PET imaging as a pharmacodynamic biomarker in patients with ER+ tumors treated with Z-endoxifen.

METHODS

Fifteen patients were recruited from a parent therapeutic trial of Z-endoxifen and underwent imaging with ¹⁸F-FES PET at baseline. Eight had positive lesions on the baseline scan and underwent follow-up imaging with ¹⁸F-FES 1-5 days post administration of Z-endoxifen.

RESULTS

Statistically significant changes (p = 0.0078) in standard uptake value (SUV)-Max were observed between the baseline and follow-up scans as early as 1 day post drug administration.

CONCLUSION

F-FES PET imaging could serve as a pharmacodynamic biomarker for patients treated with ER-directed therapy.

Abstract PD2-03: Final results of a first-in-human phase I study of the tamoxifen (TAM) metabolite, Z-Endoxifen hydrochloride (Z-Endx) in women with aromatase inhibitor (AI) refractory metastatic breast cancer (MBC) (NCT01327781)

Background: AI's are more effective than TAM in ER+ breast cancer. In AI refractory MBC, the response rate to TAM is 0% (Osborne 2011). Z-Endx is an active metabolite of TAM and among TAM treated women in the adjuvant and metastatic settings, reduced CYP2D6 metabolism and low Endx concentrations (Css &lt;20 nM) have been associated with increased likelihood of disease recurrence. Preclinical studies have demonstrated greater Z-Endx exposure and anti-tumor activity with oral Z-Endx compared to equivalent doses of oral TAM (Reid 2014)

Methods: We conducted a phase I trial to determine the maximum-tolerated dose (MTD) and evaluate the toxicities, clinical activity, and pharmacokinetics (PK) of Z-Endx in patients (pts) with ER+, AI refractory MBC. Unlimited prior endocrine regimens were allowed. An accelerated titration schedule was applied (2 pts/dose level) until moderate toxicity or DLT, followed by a 3+3 design and then to expansion cohorts (40, 80, and 100 mg/day). Z-Endx was administered orally once daily (28 day cycle). Eye exams were performed at baseline, and end of cycles 2 and 6. PK was performed during cycle 1 and prior to subsequent cycles. For pts in the expansion cohorts, tumor biopsies were obtained at baseline for DNA sequencing (Foundation Medicine). Plasma cholesterol levels were obtained at baseline and after 1 cycle.

Results: From March 2011 to Dec 2014, 41 pts (38 evaluable), median age 60, received Z-Endx once daily encompassing 7 dose levels (20-160 mg/daily). The median number of prior hormonal regimens was 2 and 3 for the dose escalation and expansion cohorts, respectively. Dose escalation was stopped at 160 mg/day given MTD not reached and attainment of mean Endx Css of 3.6 uM. Cycle 1 DLT (PE) was observed in one patient (60 mg). No eye toxicity was observed. PK demonstrated mean Endx Css of &gt; 1 uM at all dose levels ≥ 40 mg/day. Antitumor activity was observed at multiple dose levels including 3 confirmed partial responses and an additional 7 with stable disease for ≥6 cycles. Of these 10 pts, 9 had prior progression on both AI and fulvestrant and 3 additionally on TAM. After 1 cycle, total and LDL cholesterol decreased &gt; 20 points in 54% and 40% of pts, respectively. Tumor sequencing in the expansion cohorts (n=14) did not identify ESR1 mutations; however, ESR1 amplification was identified in 1 pt with prolonged stable disease (&gt;200 days). Of 6 pts with rapid progression (≤2 cycles), 4/6 had either CCND1 amplification (n=1) or at least one of the following activating mutations: ERBB2 L755S (n=1), AKT1 E17K (n=1), MTOR E1799K (n=1).

Conclusions: The direct administration of Z-END provides substantial drug exposure, acceptable toxicity, and "proof of principle" antitumor activity in endocrine resistant MBC. While the MTD was not determined, the goal of achieving Endx Css concentrations of &gt; 1 uM was achieved. Tumor sequencing identified pts with predicted and confirmed endocrine resistance. A randomized phase II comparing endoxifen (80 mg/day) with TAM in AI refractory MBC was recently activated (NCT02311933). Supported in part by CA 133049, CA186686, CA15083, CA116201, and CA15083.

Citation Format: Goetz MP, Suman VJ, Reid JM, Northfelt DW, Mahr MA, Dockter T, Kuffel M, Buhrow SA, Safgren SL, McGovern RM, Collins JM, Streicher H, Hawse JR, Haddad TC, Erlichman C, Ames MM, Ingle JN. Final results of a first-in-human phase I study of the tamoxifen (TAM) metabolite, Z-Endoxifen hydrochloride (Z-Endx) in women with aromatase inhibitor (AI) refractory metastatic breast cancer (MBC) (NCT01327781). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr PD2-03.

Granular-cell tumor of the anterior abdominal wall

We report a case of granular-cell tumor (GCT) arising in the subcutaneous tissue of the abdominal wall and describe its radiologic and histologic characteristics. The differential diagnosis of a mass in this site may include multiple benign and malignant stromal lesions. In this case, the presentation, location, and radiological features suggested a desmoid tumor (aggressive fibromatosis). Treatment of the mass involved surgical excision with negative margins, and histological analysis confirmed the presence of a benign GCT. We report a case of this rare, benign tumor to allow the radiologist and pathologist to consider this disease in the differential diagnosis when presented with similar cases.

Integrated genomic characterization reveals novel, therapeutically relevant drug targets in FGFR and EGFR pathways in sporadic intrahepatic cholangiocarcinoma

Advanced cholangiocarcinoma continues to harbor a difficult prognosis and therapeutic options have been limited. During the course of a clinical trial of whole genomic sequencing seeking druggable targets, we examined six patients with advanced cholangiocarcinoma. Integrated genome-wide and whole transcriptome sequence analyses were performed on tumors from six patients with advanced, sporadic intrahepatic cholangiocarcinoma (SIC) to identify potential therapeutically actionable events. Among the somatic events captured in our analysis, we uncovered two novel therapeutically relevant genomic contexts that when acted upon, resulted in preliminary evidence of anti-tumor activity. Genome-wide structural analysis of sequence data revealed recurrent translocation events involving the FGFR2 locus in three of six assessed patients. These observations and supporting evidence triggered the use of FGFR inhibitors in these patients. In one example, preliminary anti-tumor activity of pazopanib (in vitro FGFR2 IC₅₀≈350 nM) was noted in a patient with an FGFR2-TACC3 fusion. After progression on pazopanib, the same patient also had stable disease on ponatinib, a pan-FGFR inhibitor (in vitro, FGFR2 IC₅₀≈8 nM). In an independent non-FGFR2 translocation patient, exome and transcriptome analysis revealed an allele specific somatic nonsense mutation (E384X) in ERRFI1, a direct negative regulator of EGFR activation. Rapid and robust disease regression was noted in this ERRFI1 inactivated tumor when treated with erlotinib, an EGFR kinase inhibitor. FGFR2 fusions and ERRFI mutations may represent novel targets in sporadic intrahepatic cholangiocarcinoma and trials should be characterized in larger cohorts of patients with these aberrations.

Cholangiocarcinoma is a cancer that affects the bile ducts. Unfortunately, many patients diagnosed with cholangiocarcinoma have disease that cannot be treated with surgery or has spread to other parts of the body, thus severely limiting treatment options. New advances in drug treatment have enabled treatment of these cancers with “targeted therapy” that exploits an error in the normal functioning of a tumor cell, compared to other cells in the body, thus allowing only tumor cells to be killed by the drug. We sought to identify changes in the genetic material of cholangiocarcinoma patient tumors in order to identify potential errors in cellular functioning by utilizing cutting edge genetic sequencing technology. We identified three patient tumors possessing an FGFR2 gene that was aberrantly fused to another gene. Two of these patients were able to receive targeted therapy for FGFR2 with resulting tumor shrinkage. A fourth tumor contained an error in a gene that controls a very important cellular mechanism in cancer, termed epidermal growth factor pathway (EGFR). This patient received therapy targeting this mechanism and also demonstrated response to treatment. Thus, we have been able to utilize cutting edge technology with targeted drug treatment to personalize medical treatment for cancer in cholangiocarcinoma patients.

Preoperative chemoradiation and IOERT for unresectable or borderline resectable pancreas cancer

BACKGROUND AND OBJECTIVES

Pre-operative chemoradiation (preop CRT) plus intraoperative electron irradiation (IOERT) has been used in the multidisciplinary treatment for patients with locally advanced unresectable or borderline resectable pancreas cancer. This review was performed to evaluate survival, relapse patterns and prognostic factors in patients treated with curative intent.

METHODS

Between January 2002 and December 2010, 48 patients with locally advanced pancreatic ductal adenocarcinoma received preop CRT prior to an attempt at resection and IOERT. 31/48 (65%) patients proceeded to curative-intent surgical resection. Resection status prior to preop CRT was locally unresectable (20 patients) and borderline resectable (11 patients). Preop CRT (45-50.4 Gy/25-28 Fx in 27/31) was delivered with concurrent 5FU or gemcitabine-based regimens. Subsequent gross total resection was achieved in 16 patients (R0, 11; R1, 5). IOERT was delivered in 28 patients (dose, 10-20 Gy). 16 patients also received adjuvant post-operative systemic chemotherapy. Outcomes evaluated include survival, local failure in the EBRT field (LF), central failure in the IOERT field (CF), and distant metastases.

RESULTS

Resection status was predictive for survival and for patterns of relapse. For patients with at least a gross total resection after preop CRT (R0/R1; n=16) vs. no resection (n=15), both median and overall survival were improved (median 23 vs. 10 months; 2-year, 40% vs. 17%; 3-year, 40% vs. 0%; P=0.002). Liver or peritoneal relapse was documented in 22/31 patients (71%); LF/CF in 5/26 (16%).

CONCLUSIONS

Long term survival and disease control are achievable in select patients with borderline resectable or locally unresectable pancreas cancer when gross total surgical resection is achieved after preop CRT. Continued evaluation of curative-intent combined modality therapy is warranted in this high risk population, but additional strategies are needed to improve resectability and disease control.

Isolated supraclavicular lymph node metastasis in pancreatic adenocarcinoma: a report of three cases and review of the literature

CONTEXT

Supraclavicular lymph nodes represent a rare site of metastasis in pancreatic cancer. We report three cases of pancreatic adenocarcinoma with metastases to supraclavicular lymph nodes.

CASE REPORT

A 51-year-old male was diagnosed with locally advanced pancreatic adenocarcinoma on computed tomography (CT) scan. He was recommended neoadjuvant chemotherapy followed by chemoradiation therapy. However, positron emission tomography (PET)/CT scans and subsequent fine needle aspiration cytology showed supraclavicular lymph node metastasis. The patient received systemic chemotherapy for metastatic pancreatic adenocarcinoma. The second patient, a 66-year-old female with pancreatic adenocarcinoma, underwent pancreaticoduodenectomy and was found to have peripancreatic lymph node involvement. She received adjuvant chemotherapy and was followed-up with surveillance CT scans, which did not reveal any metastasis. However, the patient complained of neck swelling. PET/CT scan and biopsy revealed supraclavicular lymph node metastasis from a pancreatic adenocarcinoma primary. The third patient, a 79-year-old male with a past history of thyroid carcinoma who was treated with partial thyroidectomy, developed neck swelling 4 years after his surgery. Fine needle aspiration cytology was consistent with known papillary thyroid carcinoma. Staging evaluations revealed a pancreatic mass for which he underwent subtotal pancreatectomy and splenectomy. Histopathology revealed grade 3 pancreatic adenocarcinoma. Excisional biopsy of a supraclavicular lymph node showed metastatic pancreatic adenocarcinoma. PET/CT results were consistent with these findings.

CONCLUSION

In patients with pancreatic adenocarcinoma, supraclavicular lymph node metastasis represents an uncommon, but clinically significant finding that can lead to changes in treatment planning. PET imaging represents a valuable tool in the detection and follow up of these patients.

The natural history of a branch duct intraductal papillary mucinous neoplasm in a patient with Lady Windermere syndrome: a case report

CONTEXT

"Low-risk" branch duct intraductal papillary mucinous neoplasm (IPMN) is defined as pancreatic epithelial cellular proliferation of small branch ducts that lack malignant characteristics. At present, our understanding of the natural history of "low-risk" branch duct IPMN is still evolving. Lady Windermere syndrome is a disorder seen in non-smoking women with no pre-existing pulmonary disease affecting the lingula and/or right middle lobe with Mycobacterium avium-intracellulare complex. We present a case with pancreatic adenocarcinoma after a six-year surveillance of "low-risk" branch duct IPMN in an asymptomatic elderly white woman with Lady Windermere syndrome.

CASE REPORT

A 79-year-old woman was referred to our institution because of pancreatic cystic abnormalities and elevated carbohydrate antigen 19-9 (CA 19-9). While at our institution, she was also diagnosed with Lady Windermere syndrome. Multiple abdominal imaging studies, endoscopic retrograde cholangiopancreatography, computer tomography, and magnetic resonance cholangiopancreatography (MRCP) were performed in the ensuing 6 years, all consistent with "low-risk" branch duct IPMN. No progression was seen until year 6 when MRCP showed a 2 cm pancreatic cancer. Because of multiple comorbidities, the patient chose chemotherapy over a pancreaticoduodenectomy. She developed respiratory failure and died after one cycle of gemcitabine.

CONCLUSIONS

"Low-risk" branch duct IPMN may be a heterogeneous disease in which some cases can transform into malignant pancreatic neoplasms despite the absence of the so-called "high risk" features on imaging studies. Clinical management, therefore, requires individualized flexibility. In addition, when there is coexistence of Lady Windermere syndrome and pancreatic cancer, prompt diagnosis and treatment of Lady Windermere syndrome should be considered prior to chemoradiotherapy or surgery.

Risk factors for pancreatic adenocarcinoma and prospects for screening

Pancreatic cancer has one of the worst survival rates of any cancer and is the fourth leading cause of cancer mortality. Early detection and surgery are the patient's best chance for cure. However, symptoms are typically vague and occur when the cancer is unresectable. Population-based mass screening is not practical for this rare disease, though screening and early detection in asymptomatic high-risk patient populations may be indicated.

Esophageal perforation as a complication of esophagogastroduodenoscopy

Fifty years ago, esophageal perforation was common after rigid upper endoscopy. The arrival of flexible endoscopic instruments and refinement in technique have decreased its incidence; however, esophageal perforation remains an important cause of morbidity and mortality. This complication merits a high index of clinical suspicion to prevent sequelae of mediastinitis and fulminant sepsis. Although the risk of perforation with esophagogastroduodenoscopy alone is only 0.03%, this risk can increase to 17% with therapeutic interventions in the setting of underlying esophageal and systemic diseases. A wide spectrum of management options exist, ranging from conservative treatment to surgical intervention. Prompt recognition and management, within 24 hours of perforation, is critical for favorable outcomes.

Hemosuccus Pancreaticus in the Era of Capsule Endoscopy and Double Balloon Enteroscopy Complicated by Multifocal Mycobacterium chelonae/abscessus Infection

Hemosuccus pancreaticus is a rare etiology of obscure gastrointestinal bleeding characterized by bleeding into the pancreatic duct. The diagnosis may be delayed for months to years, due to the episodic nature of bleeding and failure to consider the diagnosis. Patients often undergo multiple endoscopies and radiologic evaluations prior to diagnosis. Incidental gastrointestinal findings may lead to unnecessary endoscopic and surgical interventions. This report describes a patient with hemosuccus pancreaticus diagnosed in the era of video capsule endoscopy and double balloon enteroscopy, whose management was complicated by multifocal Mycobacteria chelonae/abscessus infection.

Actinomyces meyeri osteomyelitis of the symphysis pubis following pubovaginal sling

Previous reports of pubic osteomyelitis associated with bone anchors describe symptoms presenting 10 days to 12 months postoperatively with typical pathogens including Streptococcus, Staphylococcus, Citrobacter, and Pseudomonas (Fitzgerald et al., Int Urogynecol J 10:346-348, 1999 Enzler et al., J Bone Jt Surg Am 81-A(12):1736-1740, 1999; Graham and Dmochowski, J Urol 168:2055-2058, 2004; Fialkow et al., Urology 64(6):1127-1132, 2004; Matkov et al., J Urol 160(4):1427, 1998). This case illustrates the potential for protracted symptoms and delayed diagnosis of pubic osteomyelitis with the fastidious pathogen of Actinomyces meyeri.

Indolent Enterococcal Abscess Mimicking Recurrent Renal Cell Carcinoma on MR Imaging and PET/CT after Radiofrequency Ablation

A case of asymptomatic enterococcal abscess was found to mimic recurrent renal cell carcinoma (RCC) on gadolinium-enhanced magnetic resonance (MR) imaging and positron emission tomography/computed tomography (CT) 15 months after radiofrequency ablation for RCC. This case illustrates that indolent infection can closely mimic recurrent neoplasm on imaging. The authors suggest that if bacterial and fungal cultures had been performed during the CT-guided biopsy, the subsequent open surgical procedure might have been avoided.

Titanium(IV) Citrate Speciation and Structure under Environmentally and Biologically Relevant Conditions

The water-soluble complexes of Ti(IV) with citrate are of interest in environmental, biological, and materials chemistry. The aqueous solution speciation is revealed by spectropotentiometric titration. From pH 3-8, given at least three equivalents of ligand, 3:1 citrate/titanium complexes predominate in solution with successive deprotonation of dangling carboxylates as the pH increases. In this range and under these conditions, hydroxo- or oxo-metal species are not supported by the data. At ligand/metal ratios between 1:1 and 3:1, the data are difficult to fit, and are consistent with the formation of such hydroxo- or oxo- species. Stability constants for observed species are tabulated, featuring log beta-values of 9.18 for the 1:1 complex [Ti(Hcit)](+), and 16.99, 20.41, 16.11, and 4.07 for the 3:1 complexes [Ti(H(2)cit)(3)](2-), [Ti(H(2)cit)(Hcit)(2)](4-), [Ti(Hcit)(2)(cit)](6-), and [Ti(cit)(3)](8-), respectively (citric acid = H(4)cit). Optical spectra for the species are reported. The complexes exhibit similar yet distinct spectra, featuring putative citrate-to-Ti(IV) charge-transfer absorptions (lambda(max) approximately 250-310 nm with epsilon approximately 5000-7000 M(-)(1) cm(-1)). The prevailing 3:1 citrate/titanium ratio in solution is supported by electrospray mass spectrometry data. The X-ray crystal structure of a fully deprotonated tris-citrate complex Na(8)[Ti(C(6)H(4)O(7))(3)].17H(2)O (1) (or Na(8)[Ti(cit)(3)].17H(2)O) that crystallizes from aqueous solution at pH 7-8 is reported. Compound 1 crystallizes in the triclinic space group P, with a = 11.634(2) Angstroms, b = 13.223(3) Angstroms, c = 13.291(3) Angstroms, V = 1982.9(7) Angstroms(3), and Z = 2.

Gadolinium-enhanced MRI in the evaluation of minimally invasive treatments of the prostate: correlation with histopathologic findings

OBJECTIVES

To explore the use of magnetic resonance imaging (MRI) with gadolinium enhancement as a noninvasive method to image the extent of ablation after minimally invasive treatment. Minimally invasive methods for ablating prostatic tissue have emerged as a viable option in the treatment of prostate disease. As these devices enter the mainstream of patient care, imaging methods that verify the exact location, extent, and pattern of the ablation are needed.

METHODS

Nineteen patients with prostate cancer were evaluated. All received some type of minimally invasive treatment, post-treatment gadolinium-enhanced MRI sequences, and radical retropubic prostatectomy for histopathologic evaluation. Visual comparisons of gadolinium defects and areas of coagulation necrosis as seen on histopathologic evaluation were made by us. Volumetric and two-dimensional area measurements of the ablation lesions were also compared for correlation between the MRI and histopathologic results.

RESULTS

Gadolinium-enhanced MRI could be matched to histopathologic findings by visual comparison in 17 of the 19 cases. Surgically distorted histopathologic specimens and a small periurethral lesion caused 2 patients to have MRI and histopathologic results that could not be matched. Complete volumetric measurements were available for 16 of the 19 patients and correlated strongly (r = 0.924). The two-dimensional area data for all patients also showed significant correlation (r = 0.886).

CONCLUSIONS

Correlation with histopathologic findings showed gadolinium-enhanced MRI to be useful for determining the location, pattern, and extent of necrosis caused within the prostate by minimally invasive techniques. Gadolinium-enhanced MRI gives the urologist a useful tool to evaluate the effectiveness of new minimally invasive therapies.

Contribution of indirect computed tomography venography to computed tomography angiography of the chest for the diagnosis of thromboembolic disease in two United States emergency departments

Recent reports suggest that physicians in non-ambulatory settings can use indirect CT venography (CTV) of the lower extremities immediately following spiral CT angiography (CTA) of the chest to identify patients with a negative CTA who have thromboembolic disease identified on CTV. We sought to determine the frequency of isolated deep venous thrombosis (DVT) discovered on CTV in emergency department (ED) patients with complaints suggestive of pulmonary embolism (PE) yet having a negative CTA. This study was conducted in a suburban and urban ED where patients with symptoms suspicious for PE were primarily evaluated with CTA and CTV. A total of 800 patients were studied, including 360 from the suburban ED and 440 from the urban ED. 88 (11%) patients were diagnosed with thromboembolic disease by CTA, or CTV, or both. Seventy-three patients had a CTA of the chest that was positive for PE, 42 (5.2%) of whom had evidence of both PE on CTA and DVT on CTV. Fifteen patients (2%, 95% CI = 1-3%) had a negative CTA and were subsequently found to have isolated DVT on CTV, all of whom received anticoagulation therapy. These data suggest that indirect CT venography of immediately following CT angiography of the chest significantly increased the frequency of diagnosed thromboembolic disease requiring anticoagulation in ED patients with suspected PE.

Spontaneous intramural small-bowel hematoma: imaging findings and outcome

OBJECTIVE

Our aim was to review the imaging findings and outcomes of patients with nontraumatic spontaneous intramural small-bowel hematoma.

MATERIALS AND METHODS

We retrospectively reviewed the records and radiologic studies of 13 patients with known intramural small-bowel hemorrhage.

RESULTS

The mean age at presentation was 64 years. Sixty-two percent of patients had warfarin toxicity. The diagnosis was evident on CT performed in all patients. Small-bowel obstruction was present in 85% of patients, and biliary obstruction was present in 8%. A single hematoma was present in 85% of patients, and multiple hematomas were present in 15%. The jejunum was the most common site of the hematoma (69%), followed by the ileum (38%) and duodenum (23%). The hematoma extended into the cecum in 15% of patients. The estimated average length of the hematoma was 23 cm, and the shortest segment was 8 cm. Resolution of the hematoma was seen on CT as early as 1 week after onset. Eleven patients (85%) with non-extensive hematomas were dismissed from the hospital without any short- or long-term complications (mean follow-up, 35 months). Two patients with extensive hematomas involving more than half the length of the small intestine died.

CONCLUSION

Spontaneous intramural small-bowel hematoma is rare. It occurs in patients who receive excessive anticoagulation with warfarin or who have some other risk factor for bleeding. CT characteristics include circumferential wall thickening, intramural hyperdensity, luminal narrowing, and intestinal obstruction. Early diagnosis is crucial because most patients are treated nonoperatively with a good outcome.

Spontaneous intramural small-bowel hematoma: clinical presentation and long-term outcome

HYPOTHESIS

To review our experience with the treatment of patients with nontraumatic spontaneous intramural small-bowel hematoma. Our hypothesis was that this condition resolves spontaneously in most patients.

DESIGN

A retrospective review of the records of 13 patients with nontraumatic spontaneous intramural small-bowel hematoma who presented to Mayo Clinic (Rochester, Minn; Scottsdale, Ariz; and Jacksonville, Fla) between January 1, 1983, and December 31, 2000.

SETTING

A tertiary care medical institution.

PATIENTS

Mean age at presentation was 64 years (8 men, 5 women). Patients presented with abdominal pain (13 patients), intestinal obstruction (11 patients), and biliary obstruction (1 patient). Mean duration of symptoms was 4 days. Eight patients were receiving anticoagulant therapy (mean international normalized ratio, 11.6). Only 1 patient was anemic at presentation, but 11 patients became anemic during hospitalization. Computed tomography established the diagnosis in all patients.

MAIN OUTCOME MEASURES

Short- and long-term outcomes obtained from clinical records and telephone interviews.

RESULTS

Single and multiple hematomas were present in 11 patients and 2 patients, respectively. Two patients had an exploratory operation, but no bowel resection was performed. The other 11 patients were managed with bowel rest. Two patients died of sepsis related to their coexisting medical conditions, and 11 patients left the hospital without short-term complications. At follow-up (mean, 35 months), 4 patients had died of unrelated causes, and 7 were alive; none had recurrence of bowel hematoma or intestinal obstruction.

CONCLUSION

Nonoperative treatment of spontaneous small-bowel hematoma has a good outcome in most patients.

Thymidine phosphorylase as a target for imaging and therapy with thymine analogs

PURPOSE

Thymidine phosphorylase (TPase; platelet-derived endothelial cell growth factor) is an attractive target for imaging and therapy because of the strong relationship between its expression in tumor biopsies and clinical outcome in many tumor types. Although the mechanism has yet to be explained, expression of TPase is highly associated with angiogenesis.

METHODS

Tumor cells were phenotyped for TPase activity, and incubated with thymine or its analogs (5-X-Ura). After intracellular conversion to thymidine analogs via the reverse reaction for TPase, these molecules were phosphorylated and incorporated into DNA.

RESULTS

Preferential localization was found in cells with high TPase, e.g. U937. Incorporation was enhanced in cells with high TPase by coincubation with modulators such as deoxyuridine.

CONCLUSIONS

5-X-Ura molecules can be readily labeled with positron emitters, and this finding provides support for further evaluation in vivo of their potential as probes for noninvasive external imaging of TPase, both at the time of diagnosis and during maneuvers intended to manipulate TPase. If the 5-X-Ura molecules were labeled with a therapeutic isotope, e.g. 125I or 211At, selective cytotoxicity would be expected in cells with high TPase expression. However, direct evaluation of the safety in vivo of the therapeutic approach is required. The 5-X-Ura compounds constitute a novel approach to both imaging and therapy directed towards TPase. Further, there are distinct advantages to using the imaging mode to identify tumors likely to benefit from therapy with the same set of molecules.