Metabolites as signalling molecules.

Traditional views of cellular metabolism imply that it is passively adapted to meet the demands of the cell. It is becoming increasingly clear, however, that metabolites do more than simply supply the substrates for biological processes; they also provide critical signals, either through effects on metabolic pathways or via modulation of other regulatory proteins. Recent investigation has also uncovered novel roles for several metabolites that expand their signalling influence to processes outside metabolism, including nutrient sensing and storage, embryonic development, cell survival and differentiation, and immune activation and cytokine secretion. Together, these studies suggest that, in contrast to the prevailing notion, the biochemistry of a cell is frequently governed by its underlying metabolism rather than vice versa. This important shift in perspective places common metabolites as key regulators of cell phenotype and behaviour. Yet the signalling metabolites, and the cognate targets and transducers through which they signal, are only beginning to be uncovered. In this Review, we discuss the emerging links between metabolism and cellular behaviour. We hope this will inspire further dissection of the mechanisms through which metabolic pathways and intermediates modulate cell function and will suggest possible drug targets for diseases linked to metabolic deregulation.

An AT-hook domain in MeCP2 determines the clinical course of Rett syndrome and related disorders.

Mutations in the X-linked MECP2 cause Rett syndrome, a devastating neurological disorder typified by a period of apparently normal development followed by loss of cognitive and psychomotor skills. Data from rare male patients suggest symptom onset and severity can be influenced by the location of the mutation, with amino acids 270 and 273 marking the difference between neonatal encephalopathy and death, on the one hand, and survival with deficits on the other. We therefore generated two mouse models expressing either MeCP2-R270X or MeCP2-G273X. The mice developed phenotypes at strikingly different rates and showed differential ATRX nuclear localization within the nervous system, over time, coinciding with phenotypic progression. We discovered that MeCP2 contains three AT-hook-like domains over a stretch of 250 amino acids, like HMGA DNA-bending proteins; one conserved AT-hook is disrupted in MeCP2-R270X, lending further support to the notion that one of MeCP2's key functions is to alter chromatin structure.

Wolbachia depletion blocks transmission of lymphatic filariasis by preventing chitinase-dependent parasite exsheathment.

Lymphatic filariasis is a vector-borne neglected tropical disease prioritized for global elimination. The filarial nematodes that cause the disease host a symbiotic bacterium, Wolbachia, which has been targeted using antibiotics, leading to cessation of parasite embryogenesis, waning of circulating larvae (microfilariae [mf]), and gradual cure of adult infection. One of the benefits of the anti-Wolbachia mode of action is that it avoids the rapid killing of mf, which can drive inflammatory adverse events. However, mf depleted of Wolbachia persist for several months in circulation, and thus patients treated with antibiotics are assumed to remain at risk for transmitting infections. Here, we show that Wolbachia-depleted mf rapidly lose the capacity to develop in the mosquito vector through a defect in exsheathment and inability to migrate through the gut wall. Transcriptomic and Western blotting analyses demonstrate that chitinase, an enzyme essential for mf exsheathment, is down-regulated in Wolbachia-depleted mf and correlates with their inability to exsheath and escape the mosquito midgut. Supplementation of in vitro cultures of Wolbachia-depleted mf with chitinase enzymes restores their ability to exsheath to a similar level to that observed in untreated mf. Our findings elucidate a mechanism of rapid transmission-blocking activity of filariasis after depletion of Wolbachia and adds to the broad range of biological processes of filarial nematodes that are dependent on Wolbachia symbiosis.

Symptomatic carotid webs require aggressive intervention.

OBJECTIVE: Carotid web (CaWeb) is a rare form of fibromuscular dysplasia that can produce embolic stroke. Misdiagnosis of symptomatic CaWeb as "cryptogenic stroke" or "embolic stroke of unknown source" is common and can lead to recurrent, catastrophic neurologic events. Reports of CaWeb in the literature are scarce, and their natural history is poorly understood. Appropriate management remains controversial. METHODS: CaWeb was defined as a single, shelf-like, linear projection in the posterolateral carotid bulb causing a filling defect on computed tomography angiography (CTA) or cerebral angiography. Cases of symptomatic CaWeb at a single institution with a high-volume stroke center were identified through collaborative evaluation by vascular neurologists and vascular surgeons. RESULTS: Fifty-two patients with symptomatic CaWeb were identified during a 6-year period (2016-2022). Average age was 49 years (range, 29-73 years), 35 of 52 (67%) were African American, and 18 of 52 (35%) were African American women under age 50. Patients initially presented with stroke (47/52; 90%) or transient ischemic attack (5/52; 10%). Stenosis was <50% in 49 of 52 patients (94%) based on NASCET criteria, and 0 of 52 (0%) CaWebs were identified with carotid duplex. Definitive diagnosis was made by CTA examined in multiple planes or cerebral angiography examined in a lateral projection to adequately assess the posterolateral carotid bulb, where 52 of 52 (100%) of CaWebs were seen. Early in our institutional experience, 10 of 52 patients (19%) with symptomatic CaWeb were managed initially with dual antiplatelet and statin therapy or systemic anticoagulation; all suffered ipsilateral recurrent stroke at an average interval of 43 months (range, 1-89 months), and five were left with permanent deficits. Definitive treatment included carotid endarterectomy in 27 of 50 (56%) or carotid stenting in 23 of 50 (46%). Two strokes were irrecoverable, and intervention was deferred. Web-associated thrombus was observed in 20 of 50 (40%) on angiography or grossly upon carotid exploration. Average interval from initial stroke to intervention was 39 days. After an average follow-up of 38 months, there was no reported postintervention stroke or mortality. CONCLUSIONS: To our knowledge, this is the largest single-institution analysis of symptomatic CaWeb yet reported. Our series demonstrates that carotid duplex is inadequate for diagnosis, and that medical management is unacceptable for symptomatic CaWeb. Recurrent stroke occurred in all patients managed early in our experience with medical therapy alone. We have since adopted an aggressive interventional approach in cases of symptomatic CaWeb, with no postoperative stroke reported over an average follow-up of 38 months. In younger patients presenting with cryptogenic stroke, especially African American women, detailed review of lateral cerebral angiography or multi-planar, fine-cut CTA images is required to accurately rule out or diagnose CaWeb and avoid recurrent neurologic events.

Inferring Latent Structure in Polytomous Data with a Higher-Order Diagnostic Model.

Researchers continue to develop and advance models for diagnostic research in the social and behavioral sciences. These diagnostic models (DMs) provide researchers with a framework for providing a fine-grained classification of respondents into substantively meaningful latent classes as defined by a multivariate collection of binary attributes. A central concern for DMs is advancing exploratory methods for uncovering the latent structure, which corresponds with the relationship between unobserved binary attributes and observed polytomous items with two or more response options. Multivariate behavioral polytomous data are often collected within a higher-order design where general factors underlying first-order latent variables. This study advances existing exploratory DMs for polytomous data by proposing a new method for inferring the latent structure underlying polytomous response data using a higher-order model to describe dependence among the discrete latent attributes. We report a novel Bayesian formulation that uses variable selection techniques for inferring the latent structure along with a higher-order factor model for attributes. We report evidence of accurate parameter recovery in a Monte Carlo simulation study and present results from an application to the 2012 Programme for International Student Assessment (PISA) problem-solving vignettes to demonstrate the method.

Validated transport conditions maintain the quality of washed red blood cells.

BACKGROUND: Washing red blood cell (RBC) units prior to transfusion is indicated for certain patients. In the United States, units stored at 1°C-6°C or transported at 1°C-10°C are available for issue up to 24 h, if not used immediately. The washing procedure commonly utilizes room temperature saline resulting in units starting out above the allowed temperature range. This leads to wastage if units are issued and returned too quickly before having a chance to equilibrate in a transport cooler. STUDY DESIGN AND METHODS: Here we performed an experimental study of washed RBC quality comparing "ideal" storage conditions in a blood bank refrigerator to a "real-world" simulation of unit transport, including holding in a transport cooler. Twelve RBC units were washed and allocated evenly into either condition. RESULTS: Measurements at 0, 1, 3, 6, 12, and 24 h post-washing revealed that placement in a transport cooler was associated with higher unit temperature prior to 12 h (p = .013) with a maximum difference of 9.3°C. Despite this difference, several measures of unit quality including extracellular potassium, pH, lactate, and free hemoglobin were indistinguishable between conditions (p = .382, .224, .286, .691, respectively). We selected half of the tested units from our irradiated inventory and confirmed increased potassium leak (p < .001) and accumulation of free hemoglobin (p = .012) in irradiated units. DISCUSSION: Washed units stored under approved transport conditions are acceptable to return to inventory up to 24 h after washing and we provide a prediction interval-based temperature threshold for rejecting these units, permitting reduced waste.

Eosinophil-Mediated Immune Control of Adult Filarial Nematode Infection Can Proceed in the Absence of IL-4 Receptor Signaling.

Helminth infections are accompanied by eosinophilia in parasitized tissues. Eosinophils are effectors of immunity to tissue helminths. We previously reported that in the context of experimental filarial nematode infection, optimum tissue eosinophil recruitment was coordinated by local macrophage populations following IL-4R-dependent in situ proliferation and alternative activation. However, in the current study, we identify that control of chronic adult filarial worm infection is evident in IL-4Rα-deficient (IL-4Rα-/-) mice, whereby the majority of infections do not achieve patency. An associated residual eosinophilia was apparent in infected IL-4Rα-/- mice. By treating IL-4Rα-/- mice serially with anti-CCR3 Ab or introducing a compound deficiency in CCR3 within IL-4Rα-/- mice, residual eosinophilia was ablated, and susceptibility to chronic adult Brugia malayi infection was established, promoting a functional role for CCR3-dependent eosinophil influx in immune control in the absence of IL-4/IL-13-dependent immune mechanisms. We investigated additional cytokine signals involved in residual eosinophilia in the absence IL-4Rα signaling and defined that IL-4Rα-/-/IL-5-/- double-knockout mice displayed significant eosinophil deficiency compared with IL-4Rα-/- mice and were susceptible to chronic fecund adult filarial infections. Contrastingly, there was no evidence that either IL-4R-dependent or IL-4R-independent/CCR3/IL-5-dependent immunity influenced B. malayi microfilarial loads in the blood. Our data demonstrate multiplicity of Th2-cytokine control of eosinophil tissue recruitment during chronic filarial infection and that IL-4R-independent/IL-5- and CCR3-dependent pathways are sufficient to control filarial adult infection via an eosinophil-dependent effector response prior to patency.

AWZ1066S, a highly specific anti-Wolbachia drug candidate for a short-course treatment of filariasis.

Onchocerciasis and lymphatic filariasis are two neglected tropical diseases that together affect ∼157 million people and inflict severe disability. Both diseases are caused by parasitic filarial nematodes with elimination efforts constrained by the lack of a safe drug that can kill the adult filaria (macrofilaricide). Previous proof-of-concept human trials have demonstrated that depleting >90% of the essential nematode endosymbiont bacterium, Wolbachia, using antibiotics, can lead to permanent sterilization of adult female parasites and a safe macrofilaricidal outcome. AWZ1066S is a highly specific anti-Wolbachia candidate selected through a lead optimization program focused on balancing efficacy, safety and drug metabolism/pharmacokinetic (DMPK) features of a thienopyrimidine/quinazoline scaffold derived from phenotypic screening. AWZ1066S shows superior efficacy to existing anti-Wolbachia therapies in validated preclinical models of infection and has DMPK characteristics that are compatible with a short therapeutic regimen of 7 days or less. This candidate molecule is well-positioned for onward development and has the potential to make a significant impact on communities affected by filariasis.

Dorsal Hand Rejuvenation: A Systematic Review of the Literature.

BACKGROUND: Dorsal hand appearance undergoes changes with aging. Grading systems have been designed to provide numerical scores to dorsal hand appearance. Various modalities have been utilized to improve the aesthetic appearance and rejuvenate the dorsal hand. METHODS: The MEDLINE database was searched for articles investigating dorsal hand rejuvenation. Studies were grouped by method including fat grafting, injectable filler, laser/light-based treatments and miscellaneous treatments. Treatment protocols and outcomes were compiled along with patient information and complications. RESULTS: Forty-six articles were identified for inclusion. This included 9 studies of fat grafting procedures, 20 studies of injectable filler, 10 studies of laser/light-based treatments and 7 miscellaneous. Most studies showed overall good results with high patient satisfaction. Satisfaction rates were lower in laser/light-based treatments compared with the other modalities. The average patient age for included studies ranged from 41.5 to 69. Across all studies, 96.8% of patients were female and 3.2% male. CONCLUSIONS: Procedures for dorsal hand rejuvenation in the literature include procedures to address volume atrophy and superficial wrinkling. These procedures are overall safe with most studies reporting no complications or only mild adverse events. With high satisfaction rates and anecdotal reports of increasing patient interest, these procedures represent a developing area in aesthetic surgery likely to continue increasing in popularity. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The Scientific Consensus on When a Human's Life Begins.

Peer-reviewed journals in the biological and life sciences literature have published articles that represent the biological view that a human's life begins at fertilization ("the fertilization view"). As those statements are typically offered without explanation or citation, the fertilization view seems to be uncontested by the editors, reviewers, and authors who contribute to scientific journals. However, Americans are split on whether the fertilization view is a "philosophical or religious belief" (45%) or a "biological and scientific fact" (46%), and only 38% of Americans view fertilization as the starting point of a human's life. In the two studies that explored experts' views on the matter, the fertilization view was the most popular perspective held by public health and IVF professionals. Since a recent study suggested that 80% of Americans view biologists as the group most qualified to determine when a human's life begins, experts in biology were surveyed to provide a new perspective to the literature on experts' views on this matter. Biologists from 1,058 academic institutions around the world assessed survey items on when a human's life begins and, overall, 96% (5337 out of 5577) affirmed the fertilization view. The founding principles of the field Science Communication suggest that scientists have an ethical and professional obligation to inform Americans, as well as people around the world, about scientific developments so members of the public can be empowered to make life decisions that are consistent with the best information available. Given that perspective-and a recent study's finding that a majority of Americans believe they deserve to know when a human's life begins in order to make informed reproductive decisions-science communicators should work to increase the level of science awareness on the fertilization view, as it stands alone as the leading biological perspective on when a human's life begins.

Interleukin-4 activated macrophages mediate immunity to filarial helminth infection by sustaining CCR3-dependent eosinophilia.

Eosinophils are effectors in immunity to tissue helminths but also induce allergic immunopathology. Mechanisms of eosinophilia in non-mucosal tissues during infection remain unresolved. Here we identify a pivotal function of tissue macrophages (Mϕ) in eosinophil anti-helminth immunity using a BALB/c mouse intra-peritoneal Brugia malayi filarial infection model. Eosinophilia, via C-C motif chemokine receptor (CCR)3, was necessary for immunity as CCR3 and eosinophil impairments rendered mice susceptible to chronic filarial infection. Post-infection, peritoneal Mϕ populations proliferated and became alternatively-activated (AAMϕ). Filarial AAMϕ development required adaptive immunity and interleukin-4 receptor-alpha. Depletion of Mϕ prior to infection suppressed eosinophilia and facilitated worm survival. Add back of filarial AAMϕ in Mϕ-depleted mice recapitulated a vigorous eosinophilia. Transfer of filarial AAMϕ into Severe-Combined Immune Deficient mice mediated immunological resistance in an eosinophil-dependent manner. Exogenous IL-4 delivery recapitulated tissue AAMϕ expansions, sustained eosinophilia and mediated immunological resistance in Mϕ-intact SCID mice. Co-culturing Brugia with filarial AAMϕ and/or filarial-recruited eosinophils confirmed eosinophils as the larvicidal cell type. Our data demonstrates that IL-4/IL-4Rα activated AAMϕ orchestrate eosinophil immunity to filarial tissue helminth infection.

Albendazole and antibiotics synergize to deliver short-course anti-Wolbachia curative treatments in preclinical models of filariasis.

Elimination of filariasis requires a macrofilaricide treatment that can be delivered within a 7-day period. Here we have identified a synergy between the anthelmintic albendazole (ABZ) and drugs depleting the filarial endosymbiont Wolbachia, a proven macrofilaricide target, which reduces treatment from several weeks to 7 days in preclinical models. ABZ had negligible effects on Wolbachia but synergized with minocycline or rifampicin (RIF) to deplete symbionts, block embryogenesis, and stop microfilariae production. Greater than 99% Wolbachia depletion following 7-day combination of RIF+ABZ also led to accelerated macrofilaricidal activity. Thus, we provide preclinical proof-of-concept of treatment shortening using antibiotic+ABZ combinations to deliver anti-Wolbachia sterilizing and macrofilaricidal effects. Our data are of immediate public health importance as RIF+ABZ are registered drugs and thus immediately implementable to deliver a 1-wk macrofilaricide. They also suggest that novel, more potent anti-Wolbachia drugs under development may be capable of delivering further treatment shortening, to days rather than weeks, if combined with benzimidazoles.

Comparison of Polypropylene and Bioabsorbable Mesh for Abdominal Wall Reinforcement following Microsurgical Breast Reconstruction.

BACKGROUND: Abdominal wall morbidity following microvascular breast reconstruction continues to be an area of interest due to both functional and aesthetic concerns. Donor-site closure technique has been shown to affect bulge and hernia rates and ranges from primary closure to various uses of mesh. Few studies to date have compared types of mesh. The present study compares BARD polypropylene to bioabsorbable GORE Bio-A (polyglycolic acid/trimethylene carbonate) mesh used as a fascial underlay with primary fascial closure. METHODS: A retrospective review of all consecutive deep inferior epigastric artery-based microvascular breast reconstructions, including perforator and muscle-sparing flaps, performed between September 2014 and February 2017 was performed. All patients underwent primary fascial closure with mesh underlay. Risk factors for the formation of an abdominal bulge or hernia were identified by multivariate logistic regression. RESULTS: Eighty-seven patients, with 123 abdominal donor sites, were included. Heavy-weight polypropylene mesh was used for 58 donor sites, while polyglycolic acid/trimethylene carbonate mesh was used in 65 donor sites. The overall incidence of bulge or hernia was 11.4%. The bioabsorbable cohort experienced significantly more bulges/hernias than the polypropylene mesh cohort (20% vs. 1.7% by donor site). Time to diagnosis of bulge was longer for the bioabsorbable group (219 ± 107 vs. 69 days). Flap type and perforator row were not associated with bulge/hernia. The polyglycolic acid/trimethylene carbonate mesh was associated with a 13.3-fold risk of bulge/hernia (p = 0.016). CONCLUSION: Polyglycolic acid/trimethylene carbonate mesh is not appropriate for anterior rectus fascia reinforcement following abdominal tissue transfer.

MeCP2 binds to non-CG methylated DNA as neurons mature, influencing transcription and the timing of onset for Rett syndrome.

Epigenetic mechanisms, such as DNA methylation, regulate transcriptional programs to afford the genome flexibility in responding to developmental and environmental cues in health and disease. A prime example involving epigenetic dysfunction is the postnatal neurodevelopmental disorder Rett syndrome (RTT), which is caused by mutations in the gene encoding methyl-CpG binding protein 2 (MeCP2). Despite decades of research, it remains unclear how MeCP2 regulates transcription or why RTT features appear 6-18 months after birth. Here we report integrated analyses of genomic binding of MeCP2, gene-expression data, and patterns of DNA methylation. In addition to the expected high-affinity binding to methylated cytosine in the CG context (mCG), we find a distinct epigenetic pattern of substantial MeCP2 binding to methylated cytosine in the non-CG context (mCH, where H = A, C, or T) in the adult brain. Unexpectedly, we discovered that genes that acquire elevated mCH after birth become preferentially misregulated in mouse models of MeCP2 disorders, suggesting that MeCP2 binding at mCH loci is key for regulating neuronal gene expression in vivo. This pattern is unique to the maturing and adult nervous system, as it requires the increase in mCH after birth to guide differential MeCP2 binding among mCG, mCH, and nonmethylated DNA elements. Notably, MeCP2 binds mCH with higher affinity than nonmethylated identical DNA sequences to influence the level of Bdnf, a gene implicated in the pathophysiology of RTT. This study thus provides insight into the molecular mechanism governing MeCP2 targeting and sheds light on the delayed onset of RTT symptoms.

T2*-based MR imaging of hyperglycemia-induced hemichorea-hemiballism.

INTRODUCTION: Hyperglycemia can induce hemichorea-hemiballism, especially in elderly type II diabetics. CT and MRI findings include hyperdensity and T1-shortening in the contralateral lentiform nucleus, respectively. This study explores the associated imaging findings on T2*-based sequences. METHODS: Six patients with clinically documented hyperglycemia-induced hemichorea-hemiballism who had undergone MR imaging with a T2*-based sequence (T2* gradient echo or susceptibility-weighted imaging) were included in this retrospective case series. RESULTS: All six patients demonstrated T1-shortening contralateral to their hemichorea-hemiballism. T2*-based sequences demonstrated unilateral hypointense signal within the striatum in four patients. One patient had mild bilateral striatal hyperintensities, while another did not show significant signal changes. CONCLUSION: It is important for the radiologist to be aware of the signal changes that can be seen on T2*-based sequences in hyperglycemia-induced hemochorea-hemiballism.

Karyopherin α 3 and karyopherin α 4 proteins mediate the nuclear import of methyl-CpG binding protein 2.

Methyl-CpG binding protein 2 (MeCP2) is a nuclear protein with important roles in regulating chromatin structure and gene expression, and mutations in MECP2 cause Rett syndrome (RTT). Within the MeCP2 protein sequence, the nuclear localization signal (NLS) is reported to reside between amino acids 255-271, and certain RTT-causing mutations overlap with the MeCP2 NLS, suggesting that they may alter nuclear localization. One such mutation, R270X, is predicted to interfere with the localization of MeCP2, but recent in vivo studies have demonstrated that this mutant remains entirely nuclear. To clarify the mechanism of MeCP2 nuclear import, we isolated proteins that interact with the NLS and identified karyopherin α 3 (KPNA3 or Kap-α3) and karyopherin α 4 (KPNA4 or Kap-α4) as key binding partners of MeCP2. MeCP2-R270X did not interact with KPNA4, consistent with a requirement for an intact NLS in this interaction. However, this mutant retains binding to KPNA3, accounting for the normal localization of MeCP2-R270X to the nucleus. These data provide a mechanism for MeCP2 nuclear import and have implications for the design of therapeutics aimed at modulating the function of MeCP2 in RTT patients.

Autophagy regulates Wolbachia populations across diverse symbiotic associations.

Wolbachia are widespread and abundant intracellular symbionts of arthropods and filarial nematodes. Their symbiotic relationships encompass obligate mutualism, commensalism, parasitism, and pathogenicity. A consequence of these diverse associations is that Wolbachia encounter a wide range of host cells and intracellular immune defense mechanisms of invertebrates, which they must evade to maintain their populations and spread to new hosts. Here we show that autophagy, a conserved intracellular defense mechanism and regulator of cell homeostasis, is a major immune recognition and regulatory process that determines the size of Wolbachia populations. The regulation of Wolbachia populations by autophagy occurs across all distinct symbiotic relationships and can be manipulated either chemically or genetically to modulate the Wolbachia population load. The recognition and activation of host autophagy is particularly apparent in rapidly replicating strains of Wolbachia found in somatic tissues of Drosophila and filarial nematodes. In filarial nematodes, which host a mutualistic association with Wolbachia, the use of antibiotics such as doxycycline to eliminate Wolbachia has emerged as a promising approach to their treatment and control. Here we show that the activation of host nematode autophagy reduces bacterial loads to the same magnitude as antibiotic therapy; thus we identify a bactericidal mode of action targeting Wolbachia that can be exploited for the development of chemotherapeutic agents against onchocerciasis, lymphatic filariasis, and heartworm.

Diffusion kurtosis imaging: an emerging technique for evaluating the microstructural environment of the brain.

OBJECTIVE: Diffusion kurtosis imaging is an emerging technique based on the non-gaussian diffusion of water in biologic systems. The purpose of this article is to introduce and discuss the ongoing research and potential clinical applications of this technique. CONCLUSION: Diffusion kurtosis imaging provides independent and complementary information to that acquired with traditional diffusion techniques. The additional information is thought to indicate the complexity of the microstructural environment of the imaged tissue and may lead to broad-reaching applications in all aspects of neuroradiology.

Restricted Latent Class Models for Nominal Response Data: Identifiability and Estimation.

Restricted latent class models (RLCMs) provide an important framework for diagnosing and classifying respondents on a collection of multivariate binary responses. Recent research made significant advances in theory for establishing identifiability conditions for RLCMs with binary and polytomous response data. Multiclass data, which are unordered nominal response data, are also widely collected in the social sciences and psychometrics via forced-choice inventories and multiple choice tests. We establish new identifiability conditions for parameters of RLCMs for multiclass data and discuss the implications for substantive applications. The new identifiability conditions are applicable to a wealth of RLCMs for polytomous and nominal response data. We propose a Bayesian framework for inferring model parameters, assess parameter recovery in a Monte Carlo simulation study, and present an application of the model to a real dataset.