Mebamamide C, a deoxy analogue of mebamamides in Bryopsis marine green algae and Elysia sacoglossan mollusks

Kahalalides, originally isolated from the sacoglossan mollusk Elysia rufescens, have been found in various Elysia and Bryopsis species, with over 20 variants identified to date. These compounds are biosynthesized by Candidatus Endobryopsis kahalalidefaciens within Bryopsis species. In this study, we report the isolation and structural determination of a new cyclic depsipeptide, mebamamide C (1), from Bryopsis sp. The planar structure was determined by spectroscopic data analyses, and the absolute configurations were determined using Marfey's method and modified Mosher's method. Additionally, our study explores the chemical relationship between Bryopsis algae and Elysia mollusks. The individual chemical profiles of these marine organisms highlight a fascinating aspect of marine chemical ecology. The distinct, species-specific chemical profiles observed in Elysia species imply the possibility of a symbiotic relationship with the kahalalide-producing bacteria.

A comparative study of the CT effective dose in whole-body 18F-FDG PET/CT for arm-raised position and arm-lowered position

INTRODUCTION

This study aimed to investigate and compare the effective dose (ED) delivered by computed tomography (CT) in whole-body positron emission tomography/CT (WB-PET/CT) scans between patients positioned with their arms-raised and those with their arms-lowered during the scan on a large population.

METHODS

The retrospective study involved 785 oncology patients who underwent WB-PET/CT scans with 18F-FDG between January and June 2019. Exclusion criteria were applied, resulting in a final analysis of data from 732 adult patients. All of the patients were measured height and weight, and the ED from CT in WB-PET/CT was estimated using the dose length product value and a conversion factor. Statistical analyses were conducted to explore relationships between factors and the ED. Linear regression analysis was performed to investigate connections between weight and ED, and height and ED. Multiple linear regression was used to predict ED based on sex, weight, and arm position.

RESULTS

The arm-lowered group had a higher ED than the arm-raised group, and the median dose was 1.1 times higher in the arm-lowered group. The difference in ED between the two groups was found to be greater with higher body weight. Arm-position (β = 0.460), sex (β = -0.190), and weight (β = 0.057) were significant predictors of ED.

CONCLUSION

This study demonstrated that arm position, sex, and weight were significant factors influencing the ED from CT scans in WB-PET/CT.

IMPLICATIONS FOR PRACTICE

The research underscores the importance of considering these factors when evaluating radiation exposure in clinical practice, particularly for patients undergoing WB-CT imaging. These findings contribute to a better understanding of the radiation dosimetry associated with different patient positions during WB-PET/CT scans.

5, 6, 11-trideoxy tetrodotoxin attracts tiger puffer Takifugu rubripes

Tetrodotoxin (TTX) is a potent neurotoxin that binds to voltage-gated sodium channels and blocks the passage of sodium ions. TTX is widely distributed in both terrestrial and marine organisms, and the toxic puffers are believed to accumulate TTX through the food chain. Although pufferfish was previously thought to be attracted by TTX, recent finding from electroolfactogram (EOG) studies have indicated that the olfactory epithelium of T. alboplumbeus responded to 5, 6, 11-trideoxyTTX (TDT), but not to TTX itself. In this study, we examined behavioral experiments for Takifugu rubripes to distinguish between TTX and TDT under static and flow-through conditions. Our data clearly suggested that T. rubripes juveniles were attracted to TDT, not TTX. Moreover, we determined that the minimum effective dose of TDT to attract the puffer was 1-2 nmol of TDT under static conditions and 50-60 nmol of TDT under flow-through conditions. Following the experiments under static conditions, numerous bite marks by the pufferfish were found solely on the agarose gel infused with TDT. Based on these finding, we hypothesize that the pufferfish are attracted to TDT derived from prey, leading them effectively become toxic.

Evaluation of cortical bone remodeling in canines treated with daily and weekly administrations of teriparatide by establishing AI-driven morphometric analyses and GIS-based spatial mapping

Larger animal models with a well-developed Haversian system, as observed in humans, are ideal to analyze cortical bone remodeling in pharmacological studies of anti-osteoporosis drugs, although they have some limitations in controlling individual variability in size, weight, age, and number. This study aimed to morphometrically analyze cortical bone remodeling focusing on Haversian canals in dogs using four regimens of TPTD with daily and weekly administrations at lower and higher weekly doses (4.9 μg/kg/week and 19.8 μg/kg/week, respectively) for 9 months. A micro-computed tomography-based analysis showed no significant differences among regimen groups. By establishing artificial intelligence (AI)-driven morphometric analyses and geographical information system (GIS)-based spatial mapping of Haversian canals that does not require confocal microscopy but is possible with more commonly used wide field microscopes, we successfully observed significant morphometric distinctions among regimens applied even in dogs. Our analytical results suggested that the daily higher regimen specifically increased the number of eroded pores creating spaces between existing canals, thus stimulating cortical bone remodeling.

Structure Determination of Kahalalide Analogues Based on Metagenomic Analysis of a Bryopsis sp. Marine Green Alga

Two kahalalide analogues were isolated from a Bryopsis sp. marine green alga. Even though our initial structure determination of the peptides by NMR and MS identified them as kahalalide Z1 (KZ1; 3) and Z2 (KZ2; 4), the absolute configuration of the Thr residues by Marfey's analysis was different from those found in kahalalide F (KF), 3, and 4. To ascertain the absolute configuration of the amino acid residues genetically, we conducted a metagenomic analysis for symbiotic bacteria in the alga, leading to the biosynthetic gene cluster (BGC) responsible for producing the kahalalides named kahalalides Z3 (KZ3; 1) and Z4 (KZ4; 2). The identification of amino acid residues based on the A-domain suggested these peptides possess the amino acid sequence d-allo-Thr-l-Val-l-Val-d-Val residues at the N-terminus, instead of the d-Val-l-Thr-l-Val-d-Val residues found in KF, 3, and 4. The N-terminal amino acid sequence including absolute configuration was unambiguously determined by a comparison of LCMS data of synthetic tetrapeptides and the hydrolysates derived from 1 and 2. This structural difference is caused by swapping the substrate specificities of the first two A-domains.

Enigmazole Phosphomacrolides from the Marine Sponge Cinachyrella enigmatica

Enigmazole B (1) and four new analogues, cis-enigmazole B (2), dehydroenigmazole B (3), enigmimide B (4), and enigmimide A (5), were isolated from the marine sponge Cinachyrella enigmatica. Their planar structures were elucidated by detailed NMR and MS data analyses, which established 1-3 to be oxazole-substituted 18-membered phosphomacrolides, while 4 and 5 were oxazole ring-opened congeners. The relative and absolute configurations in 1 were determined by a combination of chemical transformations and spectroscopic analyses. Photooxidation of the oxazole moiety in 1 gave enigmimide B (4), thus establishing that 4 has the same absolute configuration of 1. Enigmazole B (1) along with analogues 2 and 3 showed cytotoxicity against murine IC-2 mast cells with IC50 values of 3.6-7.0 μM. The enigmimides (4 and 5) and dephosphoenigmazoles did not show cytotoxicity (IC50 > 10 μM), implying that both the oxazole moiety and the phosphate group are necessary for the cytotoxicity of the enigmazole class macrolides.

Effect of HER2-targeted therapy on PDX and PDX-derived organoids generated from HER2-positive salivary duct carcinoma

BACKGROUND

We previously established a patient-derived xenograft (PDX) model, patient-derived organoids (PDOs), and PDX-derived organoids (PDXOs) for salivary duct carcinoma (SDC). Using these models, this study examined the therapeutic effect of human epidermal growth factor receptor 2 (HER2) blockade on HER2-positive SDC.

METHODS

The therapeutic effect of lapatinib was assessed in SDC PDXOs with regards to cell growth, receptor/downstream signaling molecule expression, phosphorylation levels, and apoptosis. Effect of lapatinib treatment was evaluated in vivo in SDC PDX mice.

RESULTS

The siRNA knockdown of HER2 and lapatinib suppressed cell proliferation in SDC PDXOs. Lapatinib inhibited the phosphorylation of HER2 and its downstream targets, and induced apoptosis in SDC PDXOs. Lapatinib also significantly reduced tumor volumes compared with that of the control in SDC PDX mice.

CONCLUSION

For the first time, we demonstrated the efficacy of anti-HER2 therapy in HER2-positive SDC using preclinical models of SDC PDX and PDXO.

Establishment of experimental salivary gland cancer models using organoid culture and patient-derived xenografting

Purpose

Depending on its histological subtype, salivary gland carcinoma (SGC) may have a poor prognosis. Due to the scarcity of preclinical experimental models, its molecular biology has so far remained largely unknown, hampering the development of new treatment modalities for patients with these malignancies. The aim of this study was to generate experimental human SGC models of multiple histological subtypes using patient-derived xenograft (PDX) and organoid culture techniques.

Methods

Tumor specimens from surgically resected SGCs were processed for the preparation of PDXs and patient-derived organoids (PDOs). Specimens from SGC PDXs were also processed for PDX-derived organoid (PDXO) generation. In vivo tumorigenicity was assessed using orthotopic transplantation of SGC organoids. The pathological characteristics of each model were compared to those of the original tumors using immunohistochemistry. RNA-seq was used to analyze the genetic traits of our models.

Results

Three series of PDOs, PDXs and PDXOs of salivary duct carcinomas, one series of PDOs, PDXs and PDXOs of mucoepidermoid carcinomas and PDXs of myoepithelial carcinomas were successfully generated. We found that PDXs and orthotopic transplants from PDOs/PDXOs showed similar histological features as the original tumors. Our models also retained their genetic traits, i.e., transcription profiles, genomic variants and fusion genes of the corresponding histological subtypes.

Conclusion

We report the generation of SGC PDOs, PDXs and PDXOs of multiple histological subtypes, recapitulating the histological and genetical characteristics of the original tumors. These experimental SGC models may serve as a useful resource for the development of novel therapeutic strategies and for investigating the molecular mechanisms underlying the development of these malignancies.

Single-cell metabolite detection and genomics reveals uncultivated talented producer

The production of bioactive metabolites is increasingly recognized as an important function of host-associated bacteria. An example is defensive symbiosis that might account for much of the chemical richness of marine invertebrates including sponges (Porifera), 1 of the oldest metazoans. However, most bacterial members of sponge microbiomes have not been cultivated or sequenced, and therefore, remain unrecognized. Unequivocally linking metabolic functions to a cellular source in sponge microbiomes is, therefore, a challenge. Here, we report an analysis pipeline of microfluidic encapsulation, Raman microscopy, and integrated digital genomics (MERMAID) for an efficient identification of uncultivated producers. We applied this method to the chemically rich bacteriosponge (sponge that hosts a rich bacterial community) Theonella swinhoei, previously shown to contain 'Entotheonella' symbionts that produce most of the bioactive substances isolated from the sponge. As an exception, the antifungal aurantosides had remained unassigned to a source. Raman-guided single-bacterial analysis and sequencing revealed a cryptic, distinct multiproducer, 'Candidatus Poriflexus aureus' from a new Chloroflexi lineage as the aurantoside producer. Its exceptionally large genome contains numerous biosynthetic loci and suggested an even higher chemical richness of this sponge than previously appreciated. This study highlights the importance of complementary technologies to uncover microbiome functions, reveals remarkable parallels between distantly related symbionts of the same host, and adds functional support for diverse chemically prolific lineages being present in microbial dark matter.

Assessment of the albumin-bilirubin grade as a prognostic factor in patients with non-small-cell lung cancer receiving anti-PD-1-based therapy

Introduction

The albumin-bilirubin (ALBI) grade is a novel indicator of the liver function. Some studies showed that the ALBI grade was a prognostic and predictive biomarker for the efficacy of chemotherapy in cancer patients. The association between the ALBI grade and outcomes in patients with non-small-cell lung cancer (NSCLC) treated with cancer immunotherapy, however, is poorly understood.

Methods

We retrospectively enrolled 452 patients with advanced or recurrent NSCLC who received anti-programmed cell death protein 1 (PD-1)-based therapy between 2016 and 2019 at three medical centers in Japan. The ALBI score was calculated from albumin and bilirubin measured at the time of treatment initiation and was stratified into three categories, ALBI grade 1-3, with reference to previous reports. We examined the clinical impact of the ALBI grade on the outcomes of NSCLC patients receiving anti-PD-1-based therapy using Kaplan–Meier survival curve analysis with log-rank test and Cox proportional hazards regression analysis.

Results

The classifications of the 452 patients were as follows: grade 1, n = 158 (35.0%); grade 2, n = 271 (60.0%); and grade 3, n = 23 (5.0%). Kaplan–Meier survival curve analysis showed that the ALBI grade was significantly associated with progression-free survival and overall survival. Moreover, Cox regression analysis revealed that the ALBI grade was an independent prognostic factor for progression-free survival and overall survival.

Conclusion

The ALBI grade was an independent prognostic factor for survival in patients with advanced or recurrent NSCLC who receive anti-PD-1-based therapy. These findings should be validated in a prospective study with a larger sample size.

•

ALBI grade is calculated from albumin and bilirubin.

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We evaluated the impact of ALBI grade on survival in NSCLC patients receiving immune checkpoint inhibitors.

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ALBI grade was an independent prognostic factor for progression-free survival (PFS) and overall survival (OS).

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ALBI grade effectively stratified PFS and OS in patients with performance status 1-3.

•

ALBI grade was significantly associated with PFS and OS, regardless of programmed death ligand-1.

FosL1 Regulates Regional Metastasis of Head and Neck Squamous Cell Carcinoma by Promoting Cell Migration, Invasion, and Proliferation

BACKGROUND/AIM

We evaluated the impact of FosL1, a member of the activated protein-1 family, on the pathways leading to regional metastasis of head and neck squamous cell carcinoma (HNSCC).

MATERIALS AND METHODS

We examined the influence of small interfering RNA (siRNA) and short heparin RNA (shRNA) mediated knockdown of FosL1 on cell migration, invasion, and proliferation in vitro as well as on regional metastasis in vivo. The prognostic significance of FosL1 was also analyzed using the Kaplan- Meier plotter using data from an HNSCC patient database.

RESULTS

Down-regulation of FosL1 inhibited cell migration, invasion, and proliferation in vitro, decreased the incidence of regional metastases, and prolonged the survival of mice in vivo. We also determined that HNSCC patients with higher expression levels of FosL1 had a significantly shorter survival time than those with low expression of FosL1.

CONCLUSION

FosL1 plays a crucial role in promoting cell migration, invasion, and proliferation in HNSCC.

Establishment of PDX-derived salivary adenoid cystic carcinoma cell lines using organoid culture method

To generate a reliable preclinical model system exhibiting the molecular features of salivary adenoid cystic carcinoma (ACC) whose biology is still unclear due to the paucity of stable cell cultures. To develop new in vitro and in vivo models of ACC, the techniques of organoid culture and patient-derived tumor xenograft (PDX), which have attracted attention in other malignancies in recent years, were applied. Tumor specimens from surgically resected salivary ACC were proceeded for the preparation of PDX and organoid culture. The orthotopic transplantation of patient-derived or PDX-derived organoids was demonstrated into submandibular glands of NSG mice and those histology was evaluated. PDX-derived organoid cells were evaluated for the presence of MYB-mediated fusion genes and proceeded for in vitro drug sensitivity assay. Human ACC-derived organoids were successfully generated in three-dimensional culture and confirmed the ability of these cells to form tumors by orthotopic injection. Short-term organoid cell cultures from two individual ACC PDX tumors were also established that maintain the characteristic MYBL1 translocation and histological features of the original parent and PDX tumors. Finally, the establishment of drug sensitivity tests on these short-term cultured cells was confirmed using three different agents. This is the first to report an approach for the generation of human ACC-derived organoids as in vitro and in vivo cancer models, providing insights into understanding of the ACC biology and creating personalized therapy design for patients with ACC.

The incidence of newly diagnosed secondary cancer; sub-analysis the prospective study of the second-look procedure for transoral surgery in patients with T1 and T2 head and neck cancer

BACKGROUND

Our prospective study of patients with early T-stage head and neck cancer indicated a high incidence of newly diagnosed secondary malignancies during the follow-up period. We aimed to determine the incidence rate and risk factors of secondary malignancies in early-stage head and neck cancer patients.

METHODS

We sub-analyzed the patient data of a previous study focusing on secondary cancer incidence. The endpoints were statistical analyses of risk factors and survival and incidence rates.

RESULTS

The incidence rate of secondary cancer was 37%, the crude incidence of second primary cancers was 10.6 per 100 person-years, and the 5 year secondary cancer-free survival rate was 63%. The hypopharynx as the primary site was an independent significant predictive factor (odds ratio 3.96, 95% confidence interval 1.07-14.6, p = 0.039).

CONCLUSIONS

Early stages of laryngeal, oropharyngeal, and hypopharyngeal cancer had a risk of secondary cancer, especially hypopharyngeal cancer. Attention to the secondary cancer has to be paid during the follow-up period after controlling the early-stage disease. These findings highlight the need for awareness of the incidence of secondary cancer in cases of early-stage primary head and neck cancer.

P251 Right ventricular free wall dissection clearly detected and recorded by echocardiography: a fatal complication after inferior myocardial infarction

An 81-year-old man was transferred to our institution by ambulance because of poor feeding, general fatigue and slight disorientation lasting for a week. On arrival, he was awake and able to speak, however, his blood pressure was low at 61/43 mmHg in spite of his medical history of hypertension. His ECG showed abnormal Q waves and ST elevation in II, III, aVF leads. The echo exam detected severe hypokinesis in the left ventricular inferior wall and reduced ejection fraction at 30%. Pericardial effusion was not observed in the first echo exam. The patient was diagnosed as cardiogenic shock due to recent inferior myocardial infarction. Coronary angiography was performed, which detected total occlusion of mid right coronary artery, followed by a successful percutaneous coronary intervention (PCI) with a drug-eluting stent under the support of intra-aortic balloon pumping. Nevertheless, his blood pressure remained low and intravenous adrenaline administration was necessary during and even after PCI. To detect the cause of prolonged low blood pressure, echo was performed again immediately after PCI. The echo exam detected new findings: right ventricular posterior free wall was dissected and abnormal shunt flows were obviously observed from left ventricle to right atrium through the dissection cavity during systole. An urgent surgical repair was considered as the only option for his survival, however, his family did not accept it because the operation itself was too risky. On the next day of his admission, he passed away. Right ventricular free wall dissection is a very rare but fatal complication after inferior myocardial infarction, nevertheless, we could detect it by echocardiography with clearly recorded images.

Abstract P251 Figure.

P1386 A change in left ventricular global longitudinal strain is a prognostic indicator in congestive heart failure patients with preserved ejection fraction

Purposes

We examined how changes in left ventricular (LV) global longitudinal strain (GLS) were associated with prognosis in patients with preserved LV ejection fraction (LVEF) after congestive heart failure (HF) admission.

Methods

We studied 123 consecutive patients (age 70 ± 15 years, 55% male) who had been hospitalized due to congestive HF with preserved LVEF (> 50%). The exclusion criteria were atrial fibrillation and inadequate echo image quality for strain analyses. The patients underwent speckle-tracking echocardiography and measurement of plasma NT-ProBNP levels on the same day at the time of hospital admission as well as in the stable condition after discharge. Differences in GLS, LVEF and NT-ProBNP (delta GLS, LVEF and NT-ProBNP ; 2nd – 1st measurements) were calculated. The study end points were all-cause mortality and cardiac events.

Results

Mean periods of echo performance after hospitalization were 2 ±１days (1st echo) and 240 ± 289 days (2nd echo), respectively. During the follow-up (974 ± 626 days), 12 patients died and 25 patients were hospitalized because of HF worsening. In multivariate analysis, delta GLS and follow-up GLS were prognostic factors, whereas baseline and follow-up LVEF, NT-ProBNP, changes in LVEF and NT-ProBNP could not predict cardiac events. Delta GLS (p = 0.002) turned out to be the best independent prognosticator. Receiver operating characteristics analysis revealed that -0.6% of delta GLS was the optimal cut-off value to predict cardiac events and mortality (sensitivity 76%, specificity 67%, AUC 0.75). Kaplan-Meier analysis showed that patients with delta GLS more than -0.6% experienced significantly less cardiac events during the follow-up period (p < 0.0001, log-rank).

Conclusion

A change in LV GLS after congestive HF admission was a predictor of the prognosis in patients with preserved LVEF. It would be useful to check the changes in GLS in those with preserved LVEF after discharge.

Metachromins X and Y from a marine sponge Spongia sp. and their effects on cell cycle progression

New sesquiterpene quinones, metachromins X (1) and Y (2), together with the known metachromins C (3), J (4), and T (5), were isolated as inhibitors of cell cycle progression in the HeLa/Fucci2 cells. The structure of 1 was assigned by spectroscopic data and confirmed by a total synthesis. The planar structure of 2 was determined by interpretation of spectroscopic data, whereas its absolute configuration was analyzed by a combination of chiral HPLC and CD spectroscopy. Metachromins X (1) and C (3) arrested the cell cycle progression of HeLa/Fucci2 cells at S/G2/M phase.

SurE is a trans-acting thioesterase cyclizing two distinct non-ribosomal peptides

A new stand-alone thioesterase, SurE, is capable of offloading two different NRPS assembly lines to generate two structurally unrelated cyclopeptides.

Prognostic value of quality-of-life scores in patients with breast cancer undergoing preoperative chemotherapy

Background

Recently, evaluation of quality of life (QOL) has been recognized as a significant outcome measure in the treatment of several cancers. In this study, the Anti-Cancer Drugs-Breast (ACD-B) QOL score was used to assess disease-specific survival in women with breast cancer undergoing preoperative chemotherapy (POC).

Methods

QOL-ACD-B scores were evaluated before and after POC. The cut-off value of QOL-ACD-B contributing to events such as relapse or death was calculated by receiver operating characteristic (ROC) curve analysis.

Results

In 300 women with breast cancer treated with POC, QOL was significantly reduced (P < 0·001). A high QOL-ACD-B score before POC was an independent factor in the multivariable analysis of overall survival (hazard ratio 0·26, 95 per cent c.i. 0·04 to 0·96).

Conclusion

Evaluation by QOL-ACD-B before POC may be useful to predict the prognosis of patients with breast cancer undergoing POC.

Colony-wise Analysis of a Theonella swinhoei Marine Sponge with a Yellow Interior Permitted the Isolation of Theonellamide I

There are several examples of marine organisms whose metabolic profiles differ among conspecifics inhabiting the same region. We have analyzed the metabolic profile of each colony of a Theonella swinhoei marine sponge with a yellow interior and noticed the patchy distribution of one metabolite. This compound was isolated and its structure was studied by a combination of spectrometric analyses and chemical degradation, showing it to be a congener in the theonellamide class of bicyclic peptides. Theonellamides had previously been isolated by us only from T. swinhoei with a white interior and not from those with a yellow interior.

Poecillastrin H, a Chondropsin-Type Macrolide with a Conjugated Pentaene Moiety, from a Characella sp. Marine Sponge

Poecillastrin H (1), a chondropsin-type macrolide with a conjugated pentaene moiety, was isolated from the Characella sp. marine sponge. The planar structure of 1 was elucidated by analysis of spectroscopic data. The absolute configuration of the β-hydroxyaspartic acid residue (β-OHAsp) was determined to be d- threo by Marfey's analysis, and the mode of lactone ring formation through the OHAsp residue was determined by chemical degradation. Poecillastrin H was extremely sensitive toward light and showed potent cytotoxic activity against 3Y1 cells with an IC₅₀ value of 4.1 nM.

Miuramides A and B, Trisoxazole Macrolides from a Mycale sp. Marine Sponge That Induce a Protrusion Phenotype in Cultured Mammalian Cells

Morphology-guided cell-based screening of the extract of a Mycale sp. marine sponge led to the isolation of two trisoxazole macrolides, miuramides A (1) and B (2), which induced characteristic morphological changes in 3Y1 cells. The structure of 1 including absolute configuration was elucidated by a combination of the analysis of spectroscopic data, derivatization, and degradation. Both compounds exhibit potent cytotoxicity against 3Y1 cells.

Assessment of Canine Pancreas-Specific Lipase and Outcomes in Dogs with Hemodialysis-Dependent Acute Kidney Injury

Background

Renal replacement therapies can be life‐saving for dogs with severe acute kidney injury (AKI), however, comorbidities including pancreatitis might affect outcome.

Hypothesis/Objectives

To investigate the prevalence of pancreas‐specific lipase (Spec cPL) measurements consistent with pancreatitis (≥400 μg/L) in dogs undergoing intermittent hemodialysis (IHD) for treatment of AKI and to determine whether there were associations between 30‐days outcomes and Spec cPL measurements.

Animals

Fifty‐three client‐owned dogs presented to teaching hospitals between November 2008 and September 2016 that underwent IHD.

Methods

Retrospective medical record review from dogs that received IHD for management of AKI and also had a Spec cPL measurement. Association between survival, dialysis‐dependency, and Spec cPL measurements was assessed.

Results

Forty of 53 (76%) dogs were alive at 30‐days and 33/53(62%) had a Spec cPL result ≥400 μg/L. Spec cPL was not significantly different either between surviving (635.5 μg/L, range 29–1,001) and nonsurviving dogs (860 μg/L, range 56–1,001; P = 0.75) or between dialysis‐dependent (1,001 μg/L, range 177–1,001) and nondialysis‐dependent dogs (520 μg/L, range 29–1,001; P = 0.08). Spec cPL ≥400 μg/L was not significantly associated either with survival (P = 0.74) or dialysis‐dependency (P = 0.33).

Conclusions and Clinical Importance

Results revealed a high prevalence of Spec cPL ≥400 μg/L in dogs with AKI treated with IHD. No significant associations between Spec cPL and survival or dialysis‐dependency in dogs with AKI at 30 days were identified in the current study, however, the latter could be due to lack of power in this study.

Resolution of the Confusion in the Assignments of Configuration for the Ciliatamides, Acylated Dipeptides from Marine Sponges

Direct comparison of authentic ciliatamide A with four synthetic isomers (1-4) by means of NMR and chiral-phase HPLC revealed that ciliatamide A possesses the 12R (d-N-MePhe residue) and 22S (l-Lys residue) configurations, which were not identical with either our previous assignment or those proposed by others through total synthesis. The absolute configuration of the methionine sulfoxide residue in ciliatamide D was also revised to be d.

Structure Revision of Poecillastrin C and the Absolute Configuration of the β-Hydroxyaspartic Acid Residue

The planar structure of poecillastrin C (1) was revised through selective reduction of the ester carbon. The absolute configuration of the β-hydroxyaspartic acid (OHAsp) residue was determined to be d-threo by Marfey's analysis. The acid hydrolysate of the reduction product of 1 liberated (2R,3R)-2-amino-3,4-dihydroxybutanoic acid, demonstrating that the β-carboxyl group in poecillastrin C was esterified. The structures of poecillastrins B-D and 73-deoxychondropsin A were also revised.