E-cadherin variants associated with oral facial clefts trigger aberrant cell motility in a REG1A-dependent manner

BACKGROUND

Germline mutations of E-cadherin contribute to hereditary diffuse gastric cancer (HDGC) and congenital malformations, such as oral facial clefts (OFC). However, the molecular mechanisms through which E-cadherin loss-of-function triggers distinct clinical outcomes remain unknown. We postulate that E-cadherin-mediated disorders result from abnormal interactions with the extracellular matrix and consequent aberrant intracellular signalling, affecting the coordination of cell migration.

METHODS

Herein, we developed in vivo and in vitro models of E-cadherin mutants associated with either OFC or HDGC. Using a Drosophila approach, we addressed the impact of the different variants in cell morphology and migration ability. By combining gap closure migration assays and time-lapse microscopy, we further investigated the migration pattern of cells expressing OFC or HDGC variants. The adhesion profile of the variants was evaluated using high-throughput ECM arrays, whereas RNA sequencing technology was explored for identification of genes involved in aberrant cell motility.

RESULTS

We have demonstrated that cells expressing OFC variants exhibit an excessive motility performance and irregular leading edges, which prevent the coordinated movement of the epithelial monolayer. Importantly, we found that OFC variants promote cell adhesion to a wider variety of extracellular matrices than HDGC variants, suggesting higher plasticity in response to different microenvironments. We unveiled a distinct transcriptomic profile in the OFC setting and pinpointed REG1A as a putative regulator of this outcome. Consistent with this, specific RNAi-mediated inhibition of REG1A shifted the migration pattern of OFC expressing cells, leading to slower wound closure with coordinated leading edges.

CONCLUSIONS

We provide evidence that E-cadherin variants associated with OFC activate aberrant signalling pathways that support dynamic rearrangements of cells towards improved adaptability to the microenvironment. This proficiency results in abnormal tissue shaping and movement, possibly underlying the development of orofacial malformations.

AB0602 Temporal artery biopsy positivity rates vary more between similar hospitals than by length, with particular variation between geographic regions

Background

Clinical practice surrounding giant cell arteritis (GCA) diagnosis, including the use of temporal artery biopsy (TAB) where appropriate, needs to be consistently accurate to minimise both GCA-related end-organ damage and unnecessary glucocorticosteroid toxicity in all patients. Despite this imperative, the delivery of such clinical care, which can be measured by diagnostic investigation performance characteristics such as TAB positivity rates, varies substantially between different hospitals as it is traditionally reliant on unstructured clinical intuition. While clinical care practices plausibly might be more consistent between neighbouring hospitals given they frequently exchange medical staff and use common teaching sources, these factors are less likely to be applicable when comparing hospitals in different geographical regions within a country, even though educational standards, online information resources, and access to clinical care should be consistent. It therefore stands to reason that variation of diagnostic practice might be greater between geographically distant hospitals.

Objectives

To compare clinical practice surrounding GCA diagnosis, using TAB positivity rates, between similar hospitals in the same city and a geographically distant city in a different region, to understand the contribution of geographic separation to variance in practice.

Methods

TAB histopathological reports were reviewed at three tertiary referral hospital centres: two with neighbouring catchments in the same city, and one in a different city in a neighbouring geographical region in the same country. All three had similar resourcing and catchment demographics during the study period, and none used formal clinical risk stratification scores for GCA pre-test probability. Characteristics including age, sex, biopsy laterality, biopsy length, and hospital were captured, in addition to key histopathological features. Multivariable logistic regression with site-varying intercept was performed, using cubic splines for biopsy length to account for the non-linearity observed.

Results

TAB reports from 708 patients were captured between the three hospitals in two geographical regions. All three sites had a median age of 74 years, had 67-69% of patients being female, and reported median biopsy length between 1.7-2.0cm (Table 1). Despite these similarities, they reported positivity rates varying widely (16% and 24% in Region 1, 29% in Region 2). Apart from age, hospital site was the strongest contributing factor to TAB positivity, with length having little effect outside the very extreme high end and 90% of patients had a biopsy length <4.8cm (Figure 1). For these patients, hospital site differentiated TAB positivity across all biopsy lengths, with Region 2 reporting the highest TAB positivity odds ratio of 2.39 (95%CI: 1.37-4.19).

Table 1.CharacteristicSite1Region1 N = 218Site2Region1 N = 361Site1Region2 N = 129Bilateral laterality (%)66 (30%)105 (29%)1 (0.8%)Biopsy length (cm, median (IQR))2.0 (1.4, 3.0)1.7 (1.2, 3.5)1.7 (1.4, 2.2)Female sex (%)149 (68%)249 (69%)86 (67%)Age (y, median (IQR))74 (65, 81)74 (65, 80)74 (68, 81)TAB positivity (%)34 (16%)88 (24%)38 (29%)Figure 1.

Marginal probabilities of positive TAB obtained from the multivariable logistic regression model (A) across biopsy lengths, with 80% of observed lengths falling between the two vertical red lines (10% and 90% deciles); (B) across hospital sites; (C) across patient age.

Conclusion

Hospital site contributes more greatly to variation in GCA diagnosis clinical practice than demographics or other clinical features do, with particular variation between geographic regions. As part of clinical care standards, using a replicable pre-test GCA probability score1 to select patients is likely to be as important to diagnosis as the diagnostic tool characteristics themselves.

References

[1]Laskou F, et al. A probability score to aid the diagnosis of suspected giant cell arteritis. Clin Exp Rheumatol. 2019 Jan 1;37(Suppl 117):104-8.

Disclosure of Interests

None declared

AB0371 PATIENTS WITH PROLONGED SYMPTOMS BEFORE GCA DIAGNOSIS DO NOT INCUR HIGHER RATES OF VISUAL LOSS

Background:

Giant cell arteritis (GCA), if left untreated, confers the threat of serious cranial ischaemic complications including permanent visual loss. Although achieving a prompt and accurate diagnosis remains challenging, early diagnosis is viewed as being paramount in preventing significant morbidity.1 This raises the question of whether GCA patients are at greater risk of developing visual sequelae if there is a longer window between symptom onset and presentation.

Objectives:

To compare the frequency of lasting visual loss in patients diagnosed with GCA undergoing temporal artery biopsy (TAB) within three months and after three months of symptom onset.

Methods:

Patients who underwent TAB from January 2011 to November 2020 were identified from the pathology database of an Australian rheumatology referral centre. The diagnosis of GCA was established for each patient based on either positive TAB or, in the setting of negative TAB, clinical diagnosis by a rheumatologist. Baseline demographics, symptoms and major confounders – including age, sex, history of polymyalgia rheumatica or inflammatory arthritis, headache, jaw pain, fatigue, temporal artery tenderness or diminished pulse, and number of 1990 American College of Rheumatology (ACR) classification criteria for GCA2 fulfilled – were manually extracted from electronic medical records, as was the duration between onset of GCA symptoms and TAB, and the presence of visual loss before and after TAB. Logistic regression log-likelihood tests were used to examine the two cohorts presenting before and after three months.

Results:

There were 167 patients who underwent TAB during the study period with accessible clinical information. Of these, 31 (19%) had a delayed presentation of greater than three months from symptom onset. There were no statistical differences in patient demographics between the two groups (Table 1). No patients with delayed presentation experienced lasting, objective visual loss. In contrast, there were three cases in the cohort of patients who presented more promptly; these included two patients who developed permanent unilateral blindness, and one who experienced unilateral vision loss with some improvement at three months of follow-up.

Table 1.

Patient characteristics by time from symptom onset to TAB.

Presentation <3 monthsPresentation ≥3 monthsp-valueAge (years)73.45±10.0669.84±10.750.080Female92 (67.65%)20 (64.52%)0.738History of polymyalgia rheumatica23 (16.91%)4 (12.90%)0.586History of inflammatory arthritis6 (4.41%)2 (6.45%)0.633Headache110 (80.88%)23 (74.19%)0.406Jaw pain37 (27.21%)5 (16.13%)0.206Fatigue28 (20.59%)6 (19.35%)0.878Temporal artery tenderness or diminished pulse46 (33.82%)11 (35.48%)0.860ACR classification criteria2.83±0.992.58±0.890.199

Conclusion:

GCA patients with a lengthier course of symptoms before diagnosis did not experience any enduring visual loss. This may reflect a pattern of more aggressive disease leading to earlier presentation, but further study should explore whether longer symptom duration before diagnosis necessitates a higher degree of clinical concern.

References:

[1]Font C, Cid MC, Coll-Vinent B, López-Soto A, Grau JM. Clinical features in patients with permanent visual loss due to biopsy-proven giant cell arteritis. Br J Rheumatol. 1997 Feb;36(2):251-4. doi: 10.1093/rheumatology/36.2.251. PMID: 9133940.

[2]Hunder GG, Bloch DA, Michel BA, Stevens MB, Arend WP, Calabrese LH, Edworthy SM, Fauci AS, Leavitt RY, Lie JT, et al. The American College of Rheumatology 1990 criteria for the classification of giant cell arteritis. Arthritis Rheum. 1990 Aug;33(8):1122-8. doi: 10.1002/art.1780330810. PMID: 2202311.

Disclosure of Interests:

None declared

Monitoring silver diamine fluoride application with optical coherence tomography

The objective of this study was to investigate the use of optical coherence tomography (OCT) for monitoring changes in the structure of caries lesions overtime after treatment with silver diamine fluoride (SDF). Artificial caries lesions were formed on dentin bovine blocks. Each block was partitioned into 5 windows: one lesion was covered by nail varnish as control (LC), one sound window was covered with nail varnish (SC), one sound window was exposed to SDF (SCT), one lesion received 2 applications of SDF (L2), while the other lesion received one application of SDF (L1). Each window was scanned using OCT before SDF application, and every week subsequently, for 12 weeks after initial SDF treatment. Parameters such as mean intensity and the width of the peak of increased reflectivity located at the sample surface and the intensity at a depth of 180-μm were monitored. High-resolution microscopy was also used to for the analysis of selected samples. Changes in the parameters measured showed significant changes on dentin lesions after SDF application. OCT resolved structural changes after SDF application as well as changes overtime. High resolution microscopy images confirm penetration of SDF into the samples. Such changes can potentially be monitored to determine if and when re-application of SDF is needed.

Thermal Imaging of Root Caries In Vivo

Improved methods are needed to assess the structure and activity of lesions on root surfaces in order to improve clinical decision making. Conventional visual and tactile methods for assessing lesion activity are not reliable, and the clinician is often unable to evaluate if the lesion is progressing or has remineralized. An important marker of an arrested lesion is a highly mineralized surface zone that forms when mineral is deposited in the outer layer of the lesion. In vitro studies have shown that a mineralized surface zone influences the kinetics of water evaporation and the surface temperature while drying. Temperature changes can be monitored by measuring the thermal emission with thermal imaging. Studies have also shown that the depth and severity of demineralization and the thickness of the highly mineralized transparent surface zone on arrested lesions can be measured nondestructively with optical coherence tomography (OCT). Thermal imaging at 8-µm to 13-µm wavelengths was completed on 30 test subjects with a suspected active root caries lesion by monitoring thermal emission from the tooth surfaces during 30 s of air drying. Lesions were also evaluated using cross-polarization OCT (CP-OCT) during lesion dehydration to identify transparent surface zones indicative of arrested lesions and determine if shrinkage occurred during drying. The overall thermal emission recorded during drying was significantly different (P < 0.001) when comparing sound tooth surfaces, lesion areas identified as arrested, and lesion areas identified as active, demonstrating that thermal imaging is a promising approach for the clinical assessment of lesion activity on root surfaces. Ten of the lesions in this study had distinct areas with transparent surface zones that were visible in CP-OCT images. Shrinkage was detected with CP-OCT during drying for 12 lesions. This study confirms that these novel approaches for assessing lesion activity on root surfaces can be implemented in vivo.

SAT0279 FACTORS PREDICTIVE OF POSITIVE TEMPORAL ARTERY BIOPSY IN TWO AUSTRALIAN COHORTS

Background:

Temporal artery biopsy (TAB) is widely recognised as the diagnostic gold standard for GCA despite having a poor sensitivity due to the presence of ‘skip’ lesions. There is, however, a lack of consensus guiding TAB practice, particularly in relation to optimal length, need for bilateral specimens, and number of segments examined.

Objectives:

To investigate the impact of factors such as total biopsied length, laterality, segment number, and referral centre on histopathological outcomes in an Australian setting.

Methods:

Reports for all available biopsy specimens labelled “temporal artery” were extracted from the pathology service records of two rheumatology referral centres with adjacent geographic catchments. Each histopathology report was manually reviewed to establish length of biopsied artery, laterality, and number of segments, along with patient demographics such as age, sex, and referral centre. Key histopathological findings including intimal hyperplasia, disruption of the internal elastic lamina, presence of giant cells, and adventitial inflammation were recorded. Multivariable logistic regression with site-varying intercept was performed.

Results:

TAB reports from a total of 577 patients were captured, with results available from the two centres from 1999-2019 and 2010-2019 respectively. The mean age in this group was 73, and 69% were female (Table 1). A bilateral TAB was performed in 29%, and the mean total biopsy length was 2.5cm. Of these patients, 122 had positive biopsies (21%), with intimal hyperplasia reported in 100 (17%), giant cells in 83 (14%), and adventitial findings in 68 (12%). Positive biopsy weakly correlated with increased total length of biopsy in centimetres (OR 1.25 [1.06-1.47]) (Figure 1) and increased age in years (OR 1.02 [1.00-1.05]) but not laterality or sex (Table 2). There was a substantial difference between the two centres, which was incompletely accounted for once corrected for total biopsy length and calendar year of biopsy, suggesting either unmeasured differences in patient demographics or a difference in clinical practice. This change was preserved across analysis of different histopathological subtypes.

Table 1.

Patient characteristics by biopsy result.

Negative(n = 455)Positive(n = 122)Total(n = 577)Age (years) Mean (SD)72 (± 11)75 (± 8.9)73 (± 10)Sex Female310 (68%)88 (72%)398 (69%) Male145 (32%)34 (28%)179 (31%)Maximum biopsy length (cm) Mean (SD)1.8 (± 0.86)2.0 (± 1.10)1.9 (± 0.92)Total biopsy length (cm) Mean (SD)2.4 (± 1.6)2.8 (± 2.1)2.5 (± 1.7)Mean biopsy length (cm) Mean (SD)1.7 (± 0.78)1.9 (± 0.97)1.7 (± 0.83)Laterality Bilateral130 (29%)39 (32%)169 (29%) Unilateral325 (71%)83 (68%)408 (71%)Table 2.

Associations with positive TAB on multivariable logistic regression.

Overall positive findingIntimal hyperplasiaGiant cellsAdventitial inflammationTotal biopsy length (cm)1.25(1.06-1.47)1.18(0.98-1.40)1.21(1.00-1.46)1.07(0.87-1.31)Unilateral (vs. bilateral)1.56(0.82-3.07)1.12(0.56-2.30)1.28(0.61-2.77)0.82(0.38-1.82)Age (years)1.02(1.00-1.05)1.02(1.00-1.04)1.03(1.00-1.05)1.00(0.98-1.03)Male (vs. female)0.83(0.52-1.29)0.63(0.37-1.05)0.59(0.32-0.92)0.75(0.41-1.31)Centre 2 (vs. centre 1)0.54(0.34-0.84)0.41(0.24-0.68)0.55(0.32-0.92)0.46(0.25-0.82)Figure 1.

The effect of total biopsy length on result, stratified by laterality.

Conclusion:

Total biopsy length was weakly associated with a positive TAB result, but differences in results between referral centres independent of biopsy length suggest other selection factors may be important in determining TAB yield. Examination of differences in results between a greater number of referral centres would assist in determining the extent of this variability.

Disclosure of Interests:

None declared

Breast cancer: insights in disease and influence of drug methotrexate

According to the World Health Organization, cancer is one of the leading causes of morbidity and mortality worldwide. The previously estimated 14 million new cases in the year of 2012 are expected to rise, yearly, over the following 2 decades. Among women, breast cancer is the most common one. In 2012, almost 1.7 million people were diagnosed worldwide and half a million died from the disease. Despite having several treatments available, from surgery to chemotherapy, most of these treatments have severe adverse effects. Chemotherapy has a narrow therapeutic window and requires high dosage treatment in patients with advanced-stage cancers and further need innovative treatment strategies. Although methotrexate (MTX) is not a first line drug used against breast cancer, however, it might be valuable to fight the disease. MTX is an effective and cheap drug that might impair malignant growth without irreversible damage to normal tissues. Nevertheless, while MTX does present some disadvantages including poor solubility and low permeability, several strategies are being used to discover and provide novel and effective targeted treatment against breast cancer. In this review, we analyze the chemotherapy of breast cancer and its relationship with drug MTX.

Transcriptomic Characterization of the South American Freshwater Stingray Potamotrygon motoro Venom Apparatus

Venomous animals are found through a wide taxonomic range including cartilaginous fish such as the freshwater stingray Potamotrygon motoro occurring in South America, which can injure people and cause venom-related symptoms. Ensuring the efficacy of drug development to treat stingray injuries can be assisted by the knowledge of the venom composition. Here we performed a detailed transcriptomic characterization of the venom gland of the South American freshwater stingray Potamotrygon motoro. The transcripts retrieved showed 418 hits to venom components (comparably to 426 and 396 hits in other two Potamotrygon species), with high expression levels of hyaluronidase, cystatin and calglandulin along with hits uniquely found in P. motoro such as DELTA-alicitoxin-Pse1b, Augerpeptide hhe53 and PI-actitoxin-Aeq3a. We also identified undescribed molecules with extremely high expression values with sequence similarity to the SE-cephalotoxin and Rapunzel genes. Comparative analyses showed that despite being closely related, there may be significant variation among the venoms of freshwater stingrays, highlighting the importance of considering elicit care in handling different envenomation cases. Since hyaluronidase represents a major component of fish venom, we have performed phylogenetic and selective pressure analyses of this gene/protein across all fish with the available information. Results indicated an independent recruitment of the hyaluronidase into the stingray venom relative to that of venomous bony fish. The hyaluronidase residues were found to be mostly under negative selection, but 18 sites showed evidence of diversifying positive selection (P < 0.05). Our data provides new insight into stingray venom variation, composition, and selective pressure in hyaluronidase.

Estimation methods for flow imaging with high frequency ultrasound

This article proposes to estimate slow blood flow with high frequency ultrasound imaging. The proposed technique combines 2 methods. First, a statistical method, called Speckle Flow Imaging (SFI) based on the analysis of changes in the speckle pattern along time, gives an index directly related to the total velocity vector. Secondly, a block matching approach estimates the in-plane velocity components. Results on calibrated flow sequences of blood mimicking fluid have shown good agreement with the statistical model. The quantification of flow is achieved with pulsed flow and is also angle independent when the flow is perpendicular to the ultrasound beam. Speckle Tracking has been evaluated on the same data and has shown good estimation of the in-plane velocity vector when the component of velocity perpendicular to the imaging plane is inferior to 1mm/s. The results of these two methods permit the evaluation of the total 3D velocity field and the orthogonal velocity component relative to the imaging plane. This allows the quantification of blood flow (volumetric per time unit across the sequence).

Reliability and dimensionality of judgments of visually textured materials

We extended perceptual studies of the Brodatz set of textured materials. In the experiments, texture perception for different texture sets, viewing distances, or lighting intensities was examined. Subjects compared one pair of textures at a time. The main task was to rapidly rate all of the texture pairs on a number scale for their overall dissimilarities first and then for their dissimilarities according to six specified attributes (e.g., texture contrast). The implied dimensionality of perceptual texture space was usually at least four, rather than three. All six attributes proved to be useful predictors of overall dissimilarity, especially coarseness and regularity. The novel attribute texture lightness, an assessment of mean surface reflectance, was important when viewing conditions were wide-ranging. We were impressed by the general validity of texture judgments across subject, texture set, and comfortable viewing distances or lighting intensities. The attributes are nonorthogonal directions in four-dimensional perceptual space and are probably not narrow linear axes. In a supplementary experiment, we studied a completely different task: identifying textures from a distance. The dimensionality for this more refined task is similar to that for rating judgments, so our findings may have general application.

Genetic transformation of Aureobasidium pullulans

Aureobasidium pullulans strain Y117 was transformed to hygromycin resistance using plasmid pDH33, which contains the bacterial hygromycin B phosphotransferase gene (hph) fused to promoter elements of the Aspergillus niger glucoamylase gene (glaA). Southern hybridizations of transformants revealed multiple, integrated copies of the vector. The glaA promoter was not induced by starch in A. pullulans as it is in A. niger; however, the transcriptional start points were the same in both species.

Neuropsychological performance in medicated and unmedicated patients with Tourette's disorder

OBJECTIVE

To date, there have been no formal investigations of neuropsychological performance in patients with Tourette's disorder who are taking psychotropic medications. The authors conducted this study to provide such information.

METHOD

They examined the neuropsychological performance of 96 patients 6-18 years old who met DSM-III-R criteria for Tourette's disorder; 51 of these patients were taking neuroleptic medications and 45 were not. The groups were well matched with regard to age, sex, education, and duration of symptoms. Each group was given a complete neuropsychological test battery as well as instruments rating symptoms of Tourette's disorder, obsessive-compulsive characteristics, and other behavioral disturbances.

RESULTS

The patients taking medications did not differ from those not taking medications on any of the neuropsychological, intellectual, or educational measures. In addition, the groups did not differ with regard to level of Tourette's disorder symptoms.

CONCLUSIONS

The results of this investigation suggest that patients with Tourette's disorder who do not experience intolerable side effects from neuroleptic medications are able to perform on educational, intellectual, and neuropsychological tests at a level comparable to that of unmedicated patients. These results have positive implications for patients with Tourette's disorder who respond to neuroleptic medications.

Ovarian stimulation with pure follicle-stimulating hormone/human menopausal gonadotropin and improved laparoscopic aspiration needles influence the success of an in vitro fertilization program

The effect of a combined pure follicle-stimulating hormone/human menopausal gonadotropin (pFSH/hMG) ovarian stimulation regimen and modified, sharpened laparoscopic follicular aspiration needles on the number of oocytes retrieved and the oocyte/follicle ratio in 43 consecutive cycles of in vitro fertilization (IVF) were retrospectively compared with 99 consecutive preceeding cycles stimulated with hMG alone and captured with aspiration needles that had never been sharpened. A modified laparoscopic follicular aspiration needle is described. Purified FSH/hMG ovarian stimulation significantly improved the mean serum estradiol levels, number of preovulatory follicles, and, therefore, the total number of oocytes recovered per cycle. The mean ratios of oocytes recovered per preovulatory follicle documented on ultrasound, and per aspirated follicle, increased significantly using sharpened needles. Both modifications improved the success rate of our IVF program.

Ultrasound guidance for human embryo transfer

Embryo transfer is facilitated with ultrasound guidance. The 16 ultrasound-guided transfers were rated easier, and there was less catheter distortion, in comparison with 12 transfers guided by "clinical feel." The benefits we ascribe to ultrasound guidance are as follows: (1) transfers can be done with the patient supine in the lithotomy position; (2) the catheter tip is accurately positioned in the fundus of the uterine cavity; (3) the ejection of the transfer bubble into the uterus and its persistence during catheter removal and documented; and (4) the continuance of the bubble is comforting to the patient. Greater experience is needed before the impact of ultrasound-guided transfer can be correlated with the rate of pregnancy continuance.

Incidence of Z band streaming and myofibrillar disruptions in skeletal muscle from healthy young people

Skeletal muscle tissue was obtained from the vastus lateralis or peroneus brevis muscles of 34 healthy volunteers. Focal and extensive areas of Z band streaming and disruption of myofibrillar architecture without Z band streaming were quantified in Araldite-embedded specimens examined in the phase microscope. Extensive areas of Z band streaming in more than 2.0 percent of fibers was present in only two of the 34 volunteers. Myofibrillar disruptions without Z band streaming was much less common than Z band streaming. The size of extensive areas of Z band streaming or myofibrillar disruptions was quantified by counting the number of adjacent fibrils and contiguous sarcomeres occupied by either type of lesion. These data should be of use in determining if such lesions are present in excessive amounts in suspected pathologic material.