Diagnosis of Statin-Induced Necrotizing Myopathy: Contribution of Anti-HMGCR Antibodies

Over the last few years, several cases of statin-induced necrotizing myopathy have been described. This myopathy is characterized by the necrosis of muscle fibers and the presence of anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (anti-HMGCR) antibodies. Although the diagnosis of myopathies relies on muscle biopsy, which is considered the gold-standard, the search for autoantibodies has proved to be an essential contribution to the diagnosis of immune-mediated myopathies. The detection of anti-HMGCR antibodies in the patient’s serum can be performed by enzyme immunoassays, and more recently, by imunofluorescence. As for the latter, the detection of anti-HMGCR antibodies is performed on tissue sections by indirect immunofluorescence and is characterized by a typical fluorescence pattern called “HMGCR Associated Liver IFL Pattern”. The authors present two case reports that show the importance of diagnosing statin-induced necrotizing myopathy as quickly as possible and the contribution of anti-HMGCR antibody detection for the diagnosis.

The Autofluorescence Patterns of Acanthamoeba castellanii, Pseudomonas aeruginosa and Staphylococcus aureus: Effects of Antibiotics and Tetracaine

Acanthamoeba Keratitis (AK) can lead to substantial vision loss and morbidity among contact lens wearers. Misdiagnosis or delayed diagnosis is a major factor contributing to poor outcomes of AK. This study aimed to assess the effect of two antibiotics and one anaesthetic drug used in the diagnosis and nonspecific management of keratitis on the autofluorescence patterns of Acanthamoeba and two common bacteria that may also cause keratitis. Acanthamoeba castellanii ATCC 30868, Pseudomonas aeruginosa ATCC 9027, and Staphylococcus aureus ATCC 6538 were grown then diluted in either PBS (bacteria) or ¼ strength Ringer’s solution (Acanthamoeba) to give final concentrations of 0.1 OD at 660 nm or 104 cells/mL. Cells were then treated with ciprofloxacin, tetracycline, tetracaine, or no treatment (naïve). Excitation–emission matrices (EEMs) were collected for each sample with excitation at 270–500 nm with increments in 5 nm steps and emission at 280–700 nm at 2 nm steps using a Fluoromax-4 spectrometer. The data were analysed using MATLAB software to produce smoothed color-coded images of the samples tested. Acanthamoeba exhibited a distinctive fluorescence pattern compared to bacteria. The addition of antibiotics and anaesthetic had variable effects on autofluorescence. Tetracaine altered the fluorescence of all three microorganisms, whereas tetracycline did not show any effect on the fluorescence. Ciprofloxacin produced changes to the fluorescence pattern for the bacteria, but not Acanthamoeba. Fluorescence spectroscopy was able to differentiate Acanthamoeba from P. aeruginosa and S. aureus in vitro. There is a need for further assessment of the fluorescence pattern for different strains of Acanthamoeba and bacteria. Additionally, analysis of the effects of anti-amoebic drugs on the fluorescence pattern of Acanthamoeba and bacteria would be prudent before in vivo testing of the fluorescence diagnostic approach in the animal models.

Detailed analysis of 5-aminolevulinic acid induced fluorescence in different brain metastases at two specialized neurosurgical centers: experience in 157 cases

OBJECTIVEIncomplete neurosurgical resection of brain metastases (BM) due to insufficient intraoperative visualization of tumor tissue is a major clinical challenge and might result in local recurrence. Recently, visible 5-aminolevulinic acid (5-ALA) induced fluorescence was first reported in patients with BM. The aim of this study was thus to investigate, for the first time systematically, the value of 5-ALA fluorescence for intraoperative visualization of BM in a large patient cohort.METHODSAdult patients (≥ 18 years) with resection of suspected BM after preoperative 5-ALA administration were prospectively recruited at two specialized neurosurgical centers. During surgery, the fluorescence status (visible or no fluorescence); fluorescence quality (strong, vague, or none); and fluorescence homogeneity (homogeneous or heterogeneous) of each BM was investigated. Additionally, these specific fluorescence characteristics of BM were correlated with the primary tumor type and the histopathological subtype. Tumor diagnosis was established according to the current WHO 2016 criteria.RESULTSAltogether, 157 BM were surgically treated in 154 patients. Visible fluorescence was observed in 104 BM (66%), whereas fluorescence was absent in the remaining 53 cases (34%). In detail, 53 tumors (34%) showed strong fluorescence, 51 tumors (32%) showed vague fluorescence, and 53 tumors (34%) had no fluorescence. The majority of BM (84% of cases) demonstrated a heterogeneous fluorescence pattern. According to primary tumor, visible fluorescence was less frequent in BM of melanomas compared to all other tumors (p = 0.037). According to histopathological subtype, visible fluorescence was more common in BM of ductal breast cancer than all other subtypes (p = 0.008). It is of note that visible fluorescence was observed in the surrounding brain tissue after the resection of BM in 74 (67%) of 111 investigated cases as well.CONCLUSIONSIn this largest series to date, visible 5-ALA fluorescence was detected in two-thirds of BM. However, the characteristic heterogeneous fluorescence pattern and frequent lack of strong fluorescence limits the use of 5-ALA in BM and thus this technique needs further improvements.

Fluorescent pattern recognition of metal ions by nanoparticles of bovine serum albumin as a chemical nose/tongue

A sensor array mimicking a chemical nose/tongue based on bovine serum albumin nanoparticles (BSANsn) has been developed for the fluorescence pattern recognition of metal ions in biofluids.

SURG-05. EXPERIENCE PROFILING OF FLUORESCENCE-GUIDED SURGERY FOR GLIOMAS

Numerous studies reported a usefulness of 5-ALA fluorescence-guided surgery (FGS) in high grade gliomas. However, fluorescence pattern and intensity is variable among gliomas. In this study, we report our extensive experiences of FGS in various gliomas focusing on epidemiological data of fluorescence pattern. A total of 827 histologically proven glioma patients out of 900 brain tumor patients who had undergone FGS using 5-ALA during the period of 8.5 years between July 2010 and January 2019 were analyzed. Indication for FGS in glioma surgery harbored any evidence of possible high-grade foci at presumed gliomas in preoperative magnetic resonance images (MRI). Among the 827 gliomas, the number of cases corresponding to 2016 World Health Organization (WHO) grade IV, III, II, and I are 528 (58.7%), 193 (21.4%), 87 (9.7%) and 19 (2.1%), respectively. In terms of fluorescence rate, grade IV gliomas showed positive fluorescence in 95.4% of cases including strong intensity in 85.6%. Grade III gliomas showed fluorescence in about half of cases (55.0%), while 45.0% of cases did not show any fluorescence. Anaplastic oligodendroglioma had more positive rate (63.9%) than anaplastic astrocytoma (46.2%). Both grade II and I gliomas still showed positive fluorescence in about one-fourths of cases (24.1% and 26.3%, respectively). Among them ependymoma and pilocytic astrocytoma were fluorescence-prone tumors. This epidemiological data of 5-ALA fluorescence in various grades of gliomas provides fundamental reference to clinical application of FGS using 5-ALA in glioma surgery.

SURG-13. EVALUATION OF 5-ALA FLUORESCENCE IN BRAIN METASTASES OF VARIOUS PRIMARY TUMORS: A MULTICENTER STUDY WITH EXPERIENCE IN 157 CASES

INTRODUCTION: Local recurrence of brain metastases following incomplete resection is not uncommon. One reason is insufficient intraoperative visualization of tumor tissue. Recently, visible intraoperative 5-aminolevulinic acid (5-ALA) fluorescence was reported in the first brain metastases series. Thus, the aim of this study was to investigate intraoperative 5-ALA fluorescence in brain metastases at two specialized centers in the largest patient cohort up to date. METHODS: 5-ALA was administered prior to resection of 157 brain metastases in 154 patients. Intraoperatively, the fluorescence quality (strong, vague or none) and fluorescence homogeneity (homogeneous or heterogeneous) of each brain metastasis was investigated. These 5-ALA fluorescence characteristics were correlated with primary tumor and histopathological subtype according to the current World Health Organization (WHO) 2016 criteria. RESULTS: Visible 5-ALA fluorescence was observed in 104 brain metastases (66%), whereas fluorescence was absent in the remaining 53 cases (34%).53/104 (51%) brain metastases showed strong fluorescence and 51/104 (49%) vague fluorescence. The majority of brain metastases (84%) demonstrated a heterogeneous fluorescence pattern. In context of primary tumor, visible fluorescence was less frequent in brain metastases of melanomas compared to all other tumors (p=0.037). Moreover, visible fluorescence was more common for ductal breast cancer subtype than other subtypes (p=0.008). CONCLUSION: Our data indicate that 5-ALA fluorescence is a valuable for intraoperative visualization of brain metastases to improve the extent of resection and thus patient prognosis. However, the frequent heterogeneous 5-ALA fluorescence pattern and lack of strong fluorescence limits the use of 5-ALA in brain metastases, claiming for further technical refinement.