A new methodology for kerogen maturity estimation based on Raman spectroscopy and chemometric analysis

Diverse criteria or parameters have been cited as tools to determine the maturity of carbonaceous matter (CM) found in geologic samples using Raman spectroscopy. However, these approaches involve the mathematical decomposition of Raman bands which can vary with the specific method, the software employed, or even the individual user. Data should be treated spectrum by spectrum and a similar spectroscopic pre-treatment should be applied to the whole dataset. All these factors affect the final result and can introduce a wide uncertainty and bias. We propose an alternative chemometric method that avoids these sources of uncertainty by considering the entire spectrum, not just certain regions, while allowing specific regions of interest to be defined. Moreover, spectra pre-treatment is not required. We employ principal component analysis (PCA) across the whole range of spectra. While the method does not provide an absolute maturity value, it allows comparison of different CM in terms of maturity or H:C ratio. In the analysis of coal standards, samples were grouped by maturity.

POS0989 DEVELOPMENT OF INTERNATIONAL CONSENSUS ON A STANDARDIZED IMAGE ACQUISITION PROTOCOL FOR DIAGNOSTIC EVALUATION OF THE SACROILIAC JOINTS BY MRI – AN ASAS-SPARTAN COLLABORATION

Background

In 2009, ASAS published a ‘Definition of active sacroiliitis on MRI for classification of axial spondyloarthritis (axSpA)’. This definition relied on two MRI sequences to make this determination – semicoronal T1 and STIR. Since then, this approach has frequently been used for diagnosis, even though that was never the intent of the definition. In 2015, the European Society of Skeletal Radiology (ESSR) published its recommendations for an SIJ MRI image acquisition protocol (IAP) for diagnostic purposes that required 4 MRI sequences but there is still no IAP that has been widely accepted as a minimum standard worldwide. In 2020, an informal survey of 24 academic sites (12 Europe, 12 North America) confirmed that 24/24 sites performed a minimum of 3 MRI sequences for diagnosis (19 performed 4-8 sequences) because the 2-sequence protocol was considered inadequate.

Objectives

To develop the minimum requirements for a standardized IAP for MRI of the sacroiliac joints for diagnostic ascertainment of sacroiliitis.

Methods

All radiologist members of the ASAS and SPARTAN Classification in axSpA (CLASSIC) project, along with one European and one North American rheumatologist with extensive MRI experience in SpA clinical practice and research, were invited to participate in a consensus exercise. A draft IAP was circulated to all participants along with background information and justification for the draft proposal. Feedback on all issues was received by email, tabulated and recirculated. Participants were broadly in favour of the proposal and two months later a teleconference meeting took place and remaining points of contention were resolved. Examples of the proposed IAP performed on new, 10 and 22 years’ old MRI scanners were made available for review in DICOM format. Next the revised draft of the IAP was presented at the ASAS annual meeting to the entire membership on 14 January 2022, and voted on.

Results

A 4-sequence IAP, 3-semicoronal and 1-semiaxial, is recommended for diagnostic ascertainment of sacroiliitis and its differential diagnoses (Table 1). It must meet the following requirements: Semicoronal sequences should be parallel to the dorsal cortex of the S2 vertebral body, and include: 1) a sequence sensitive for the detection of active inflammation being T2-weighted with suppression of fat signal; 2) a sequence sensitive for the detection of structural damage in bone and bone marrow with T1-weighting; 3) a sequence that is designed to optimally depict the bone-cartilage interface of the articular surface and be sensitive for detection of bone erosion; plus 4) a semiaxial sequence sensitive for inflammation detection. The IAP was approved at the ASAS annual meeting by a vote of the entire membership with 91% in favour.

Table 1.

A standardized SIJ MRI Acquisition Protocol for diagnostic ascertainment of sacroiliitis

OrientationSequenceTarget Lesion(s)Semicoronal Parallel to the dorsal cortex of the S2 vertebral bodyT1-weighted Spin EchoStructural: Fat lesions, erosion, sclerosis, backfill, ankylosis.T2-weighted with suppressed fat signal (STIR, T2FS or equivalent)Inflammatory: Bone marrow edema (BME)T1-weighted with suppressed fat signal (2D or 3D T1FS)Structural: Erosion of the articular surfaceSemiaxial Perpendicular to semicoronalT2-weighted with suppressed fat signal (STIR, T2FS or equivalent)Inflammatory: Bone marrow edema (BME)

Conclusion

A standardized IAP for MRI of the sacroiliac joints for diagnostic ascertainment of sacroiliitis is recommended and should be comprised of a minimum of 4 sequences, in 2-planes, that will optimally visualize inflammation, structural damage, and the bone-cartilage interface.

Disclosure of Interests

Robert Lambert Paid instructor for: Novartis, Consultant of: Calyx, CARE Arthritis, Image Analysis Group, Xenofon Baraliakos Speakers bureau: Abbvie, Pfizer, MSD, UCB, Novartis, Lilly, Galapagos, Hexal, Paid instructor for: Abbvie, Pfizer, MSD, UCB, Novartis, Lilly, Galapagos, Hexal, Consultant of: Abbvie, Pfizer, MSD, UCB, Novartis, Lilly, Galapagos, Hexal, Grant/research support from: Abbvie, MSD, Novartis, Lilly, Stephanie Bernard Consultant of: Elsevier Amirsys, John Carrino Consultant of: Pfizer, Regeneron, Globus, Carestream, Image Analysis Group, Image Biopsy Lab, Torsten Diekhoff Speakers bureau: Novartis, MSD, Canon MS, Consultant of: Eli Lilly, Iris Eshed: None declared, Kay-Geert Hermann Speakers bureau: AbbVie, Pfizer, MSD, Novartis. Co-founder: BerlinFlame GmbH, Nele Herregods: None declared, Jacob L Jaremko: None declared, Lennart Jans: None declared, Anne Grethe Jurik: None declared, John O’Neill: None declared, Monique Reijnierse: None declared, Michael Tuite Consultant of: GE HealthCare, Walter P Maksymowych Speakers bureau: Abbvie, Janssen, Novartis, Pfizer, UCB, Consultant of: Abbvie, Boehringer Ingelheim, Celgene, Eli-Lilly, Galapagos, Novartis, Pfizer, UCB, Grant/research support from: Abbvie, Novartis, Pfizer, UCB

Developing a multi-disciplinary program for routine acetylcholine vasoreactivity testing in the cardiac catheterization laboratory

Background/Introduction

Of the patients who are referred for invasive coronary angiography 30–50% are found to have no obstructive coronary artery disease. Current ESC Guidelines for chronic coronary syndromes have a class IIa recommendation for intracoronary provocative testing with acetylcholine in patients with ischemia and no obstructive coronary artery disease (INOCA). However, there is limited guidance for pharmacy and nursing teams for the support of provocative testing in the cardiac catheterization laboratory.

Purpose

To demonstrate feasibility and safety of acetylcholine vasoreactivity testing in the cardiac catheterization laboratory.

Methods

The inpatient pharmacy developed an adapted protocol based on available evidence and facilitated a multi-disciplinary operational workflow for the assessment of vasospastic angina. 3mL acetylcholine aliquots of 1mcg/mL, 10 mcg/mL, 25 mcg/mL, 50 mcg/mL, and 100 mcg/mL were prepared by pharmacy following sterile compounding standards. The transition from provider or nursing staff compounding to pharmacy compounding provided quality assurance following United States Pharmacopeia compounding standards for improved sterility and patient safety, especially with a complicated micro-dilution recipe. Pharmacy supported the necessary guidance with optimized clinical decision support in the form of a customized order panel embedded in the electronic health record system and compounding software as another layer of standardization and quality assurance. Syringes were made available to the interventional cardiologist in the cardiac catheterization laboratory suite immediately prior to a scheduled case. Eleven orders of acetylcholine were placed with five dilution syringes per order (total 55 compounded syringes) from the customized acetylcholine provoked coronary vasospasm procedure order panel.

Results

From January 2020 to March 2021, 11 patients underwent acetylcholine vasoreactivity testing for clinical indications. One patient developed atrial fibrillation with a rapid ventricular rate during provocative testing of the right coronary artery which required elective cardioversion the following day. Of 11 patients, 9 were outpatients and 2 were inpatients. 1 patient received intravenous atropine and ondansetron due to profound bradycardia and nausea after 100mcg acetylcholine administration. No other safety events occurred.

Conclusion(s)

Provocative testing with intracoronary acetylcholine administration is safe and feasible. For clinical assessment, sterile compounding and customized order panels facilitate routine clinical assessment for patients with suspected vasospastic angina. Nursing protocols should include cardiac monitoring, medications to reverse adverse effects, and possible outcomes of provocative testing. We provide a practical description of our workflow for pharmacists, catheterization laboratory staff, and providers for routine acetylcholine provocation for the evaluation of INOCA.

Funding Acknowledgement

Type of funding sources: None.

Guidelines and recommendations on yeast cell death nomenclature

Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cel-lular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing. Here, we propose unified criteria for the defi-nition of accidental, regulated, and programmed forms of cell death in yeast based on a series of morphological and biochemical criteria. Specifically, we provide consensus guidelines on the differ-ential definition of terms including apoptosis, regulated necrosis, and autophagic cell death, as we refer to additional cell death rou-tines that are relevant for the biology of (at least some species of) yeast. As this area of investigation advances rapidly, changes and extensions to this set of recommendations will be implemented in the years to come. Nonetheless, we strongly encourage the au-thors, reviewers and editors of scientific articles to adopt these collective standards in order to establish an accurate framework for yeast cell death research and, ultimately, to accelerate the pro-gress of this vibrant field of research.

The life of [PSI]

The AAA+ disaggregase Hsp104 is essential for the maintenance and inheritance of nearly all known prions of the yeast Saccharomyces cerevisiae. Uniquely for [PSI⁺], the prion form of the Sup35 protein, there seem to be two activities, involving differing co-chaperones, by which Hsp104 affects the inheritance of [PSI⁺], the prion form of the Sup35 protein. Each pathway is also involved in protection against ageing, one through disaggregation of damaged proteins and the other through their retention in the mother cell during budding. Mutations in both Hsp104 and Sup35 affect prion inheritance by one or other of these pathways, as does manipulation of either Hsp104 enzyme activity or expression, in both vegetative (budding) divisions and in sporulation. Based on our recent finding (Ness et al. in Molec Microbiol 104:125–143, 2017) we suggest that the management of the heritable prion forms of Sup35 in [PSI⁺] cells in sporulation may be a marker for a role for Hsp104 in rejuvenation during sporulation.

Putaminal Iron Deposition<br />in HIV Infection

PURPOSE

T2 shortening (hypointensity) in magnetic resonance (MR) images of the putamen, which may be associated with iron deposition, only occurs in normal subjects over the age of 60 years. Increased or premature putaminal iron deposition may be related to brain injury. We sought to determine the correlation between MR putaminal hypointensity in HIV-infected patients and brain iron deposition.

METHODS

Eleven T2-weighted axial MR scans were retrospectively rated for the extent of putaminal hypointensity from patients who also had neuropathological examination for the extent of putaminal iron disposition. Correlations between MR putaminal hypointensity and brain iron were obtained.

RESULTS

Neuropathological examination in 9 of 10 patients with putaminal hypointensity demonstrated putaminal iron deposition, predominantly in a perivascular pattern.

CONCLUSIONS

Premature putaminal iron deposition occurs in patients with HIV infection and may be detected by MR imaging.

Analysis of the Generation and Segregation of Propagons: Entities That Propagate the [PSI+] Prion in Yeast

The propagation of the prion form of the yeast Sup35p protein, the so-called [PSI+] determinant, involves the generation and partition of a small number of particulate determinants that we propose calling “propagons.” The numbers of propagons in [PSI+] cells can be inferred from the kinetics of elimination of [PSI+] during growth in the presence of a low concentration of guanidine hydrochloride (GdnHCl). Using this and an alternative method of counting the numbers of propagons, we demonstrate considerable clonal variation in the apparent numbers of propagons between different [PSI+] yeast strains, between different cultures of the same [PSI+] yeast strain, and between different cells of the same [PSI+] culture. We provide further evidence that propagon generation is blocked by growth in GdnHCl and that it is largely confined to the S phase of the cell cycle. In addition, we show that at low propagon number there is a bias toward retention of propagons in mother cells and that production of new propagons is very rapid when cells with depleted numbers of propagons are rescued into normal growth medium. The implications of our findings with respect to yeast prion propagation mechanisms are discussed.

The [URE3] phenotype: evidence for a soluble prion in yeast

The aggregation of the two yeast proteins Sup35p and Ure2p is widely accepted as a model for explaining the prion propagation of the phenotypes [PSI+] and [URE3], respectively. Here, we demonstrate that the propagation of [URE3] cannot simply be the consequence of generating large aggregates of Ure2p, because such aggregation can be found in some conditions that are not related to the prion state of Ure2p. A comparison of [PSI+] and [URE3] aggregation demonstrates differences between these two prion mechanisms. Our findings lead us to propose a new unifying model for yeast prion propagation.

MR imaging of rotator cuff tendon tears: comparison of T2*-weighted gradient-echo and conventional dual-echo sequences

OBJECTIVE

Although MR imaging evaluation of the rotator cuff is usually done with proton density- and T2-weighted spin-echo techniques, interest also exists in T2*-weighted gradient-recalled echo techniques. The shorter scan times of T2*-weighted sequences can be used to increase the number of signal averages and thus improve the signal-to-noise ratio. Our purpose in this study was to compare the sensitivity and specificity of oblique coronal T2*-weighted MR image interpretations with conventional dual-echo T2-weighted MR image interpretations when diagnosing rotator cuff tears.

SUBJECTS AND METHODS

Forty-seven consecutive patients who underwent both MR imaging and shoulder arthroscopy were included in this study. The MR examination included both a 7 min 20 sec acquisition time proton density- and T2-weighted oblique coronal sequence and a 7 min 5 sec T2*-weighted oblique coronal sequence. The oblique coronal dual-echo T2-weighted images were evaluated by two of the authors independently, who were unaware of the arthroscopic findings. Each of the two observers graded each cuff as being intact, having a partial-thickness tear, or having a full-thickness tear. After a 3-week interval, each of the two observers then interpreted the T2*-weighted oblique coronal MR images in the same manner. Sensitivity and specificity for the two sets of interpretations were calculated in terms of the ability of the observers to use the two sequences to distinguish an intact cuff from a rotator cuff tear and to distinguish a partial-thickness cuff tear from an intact cuff or full-thickness tear. The results were then compared using Student's t test calculations.

RESULTS

For distinguishing an intact cuff from a torn cuff, the sensitivity of the observers' interpretations was lower for the T2*-weighted images than for the conventional dual-echo T2-weighted images. The specificity also decreased with interpretation of the T2*-weighted images for one observer and was unchanged for the second observer. For distinguishing a partial-thickness cuff tear from a non-partial-thickness cuff tear (intact or full-thickness tear), the sensitivity and specificity of both observers decreased with interpretations of the T2*-weighted images when compared with the conventional dual-echo T2-weighted images. The results did not reach statistical significance.

CONCLUSION

In this small study evaluating the ability of observers to diagnose rotator cuff tears on oblique coronal MR images only, interpretations of T2*-weighted images tended to be less sensitive and specific than interpretations of standard dual-echo T2-weighted images.

Initiation factor eIF-4E of Saccharomyces cerevisiae. Distribution within the cell, binding to mRNA, and consequences of its overproduction

The eukaryotic translational initiation factor 4E (eIF-4E) is an essential protein that binds the 5' cap structure with high specificity and affinity. Yeast eIF-4E is homologous to eIF-4E of higher eukaryotes, but interacts with a different set of cap-binding complex proteins. In the present study the distribution of yeast eIF-4E in Saccharomyces cerevisiae was found to be similar to that observed in higher cells, whereby the yeast factor was more concentrated in the nucleus than in the cytoplasm. Overexpression of yeast eIF-4E in S. cerevisiae exerted at most a minimal effect on growth in liquid minimal medium and was not found to influence the translation of reporter gene mRNAs bearing secondary structure in their leader regions. In a new method to study mRNA-protein interactions, biotinylated mRNAs were synthesized in vitro for use in studies of the binding of eIF-4E in yeast extracts. Streptavidin was used to adsorb the biotinylated mRNAs plus bound initiation factors. Stem-loop structures in the leader region did not influence the binding of eIF-4E or, in comparative experiments, of eIF-4A. Thus yeast eIF-4E shows both similarities and differences with respect to the distribution and function of its counterparts in higher eukaryotes.

Efficacy of gadolinium in MR brain imaging of HIV-infected patients

PURPOSE

To determine the value of gadolinium in routine head MR imaging of HIV-infected patients.

METHODS

One hundred and three consecutive human immunodeficiency virus-infected patients referred for head MR imaging were scanned without and with intravenous gadopentetate dimeglumine (Gd-DTPA) contrast.

RESULTS

The precontrast scans of 82 patients were either normal, or had atrophy or diffuse white matter changes only. Sixteen of these 82 demonstrated enhancing abnormalities: eight meningeal/ependymal enhancement and eight focal enhancing lesions. Twenty-one of the 103 scans had focal or mass lesions on the precontrast images; in eight of these scans, new information was obtained with Gd-DTPA. Of the 24 patients in both groups where new information was obtained with Gd-DTPA, the information contributed to a change in the clinical care of nine patients.

CONCLUSION

Gadolinium-enhanced MR is useful in the management of selected patients with human immunodeficiency virus infection, for example those with symptoms suggesting meningeal involvement, focal brain lesions, or if the unenhanced MR does not explain all the patient's symptoms.

Manic syndrome in AIDS

A manic syndrome in eight patients with AIDS is described. On the basis of clinical, neuropsychological, laboratory, magnetic resonance imaging, and epidemiological evidence, the authors suggest that the manic syndrome was secondary to HIV infection. The patients also developed concomitant cognitive impairment.