Multiscalar cellular automaton simulates in-vivo tumour-stroma patterns calibrated from in-vitro assay data.

BACKGROUND: The tumour stroma -or tumour microenvironment- is an important constituent of solid cancers and it is thought to be one of the main obstacles to quantitative translation of drug activity between the preclinical and clinical phases of drug development. The tumour-stroma relationship has been described as being both pro- and antitumour in multiple studies. However, the causality of this complex biological relationship between the tumour and stroma has not yet been explored in a quantitative manner in complex tumour morphologies. METHODS: To understand how these stromal and microenvironmental factors contribute to tumour physiology and how oxygen distributes within them, we have developed a lattice-based multiscalar cellular automaton model. This model uses principles of cytokine and oxygen diffusion as well as cell motility and plasticity to describe tumour-stroma landscapes. Furthermore, to calibrate the model, we propose an innovative modelling platform to extract model parameters from multiple in-vitro assays. This platform provides a novel way to extract meta-data that can be used to complement in-vivo studies and can be further applied in other contexts. RESULTS: Here we show the necessity of the tumour-stroma opposing relationship for the model simulations to successfully describe the in-vivo stromal patterns of the human lung cancer cell lines Calu3 and Calu6, as models of clinical and preclinical tumour-stromal topologies. This is especially relevant to drugs that target the tumour microenvironment, such as antiangiogenics, compounds targeting the hedgehog pathway or immune checkpoint inhibitors, and is potentially a key platform to understand the mechanistic drivers for these drugs. CONCLUSION: The tumour-stroma automaton model presented here enables the interpretation of complex in-vitro data and uses it to parametrise a model for in-vivo tumour-stromal relationships.

Diagnostic accuracy of high-definition CT coronary angiography in high-risk patients.

AIM: To assess the diagnostic accuracy of computed tomography coronary angiography (CTCA) using a combination of high-definition CT (HD-CTCA) and high level of reader experience, with invasive coronary angiography (ICA) as the reference standard, in high-risk patients for the investigation of coronary artery disease (CAD). MATERIALS AND METHODS: Three hundred high-risk patients underwent HD-CTCA and ICA. Independent experts evaluated the images for the presence of significant CAD, defined primarily as the presence of moderate (≥ 50%) stenosis and secondarily as the presence of severe (≥ 70%) stenosis in at least one coronary segment, in a blinded fashion. HD-CTCA was compared to ICA as the reference standard. RESULTS: No patients were excluded. Two hundred and six patients (69%) had moderate and 178 (59%) had severe stenosis in at least one vessel at ICA. The sensitivity, specificity, positive predictive value, and negative predictive value were 97.1%, 97.9%, 99% and 93.9% for moderate stenosis, and 98.9%, 93.4%, 95.7% and 98.3%, for severe stenosis, on a per-patient basis. CONCLUSION: The combination of HD-CTCA and experienced readers applied to a high-risk population, results in high diagnostic accuracy comparable to ICA. Modern generation CT systems in experienced hands might be considered for an expanded role.

Isolated limb perfusion for locally advanced melanoma in the immunotherapy era.

BACKGROUND: Prior to the advent of effective systemic therapy for melanoma, isolated limb perfusion (ILP) was the most effective local treatment for advanced in-transit melanoma (ITM). However, many patients who are now treated by ILP will have received prior immunotherapy. We sought to compare response rates to ILP in patients who had previously received immunotherapy compared to immunotherapy naive patients. MATERIALS AND METHODS: All patients who underwent ILP for ITM between January 2015 and July 2020 for melanoma were identified retrospectively from two tertiary institutions. Surgical morbidity and oncologic outcomes were compared between immunotherapy naive and immunotherapy pre-treated patients. RESULTS: 97 perfusions were performed for melanoma. Of those, 18 patients had undergone prior immunotherapy. There were no differences in clinicopathological characteristics or perioperative outcomes between cohorts. Surgical morbidity and local toxicity were similar between both cohorts. Patients who underwent immunotherapy prior to ILP had significantly decreased complete response (CR) rates compared with immunotherapy-naïve (6% vs 47%, p = 0.0018) and a significantly decreased overall survival (OS) and distant progression free survival (DPFS) (p = 0.0031 and p = 0.0006 respectively). There was no difference in overall response (OR), partial response (PR), stable disease (SD), progressive disease (PD) and local progression free survival (LPFS) between cohorts. CONCLUSION: Oncological outcomes and complete response rates are worse in patients who have received immunotherapy prior to ILP compared with immunotherapy naïve patients. Despite this, ILP is still a valuable second line treatment for local control in patients who have multiple, bulky and/or recurrent ITM post immunotherapy.

Temperature and Density on the Forsterite Liquid-Vapor Phase Boundary.

The physical processes during planet formation span a large range of pressures and temperatures. Giant impacts, such as the one that formed the Moon, achieve peak pressures of 100s of GPa. The peak shock states generate sufficient entropy such that subsequent decompression to low pressures intersects the liquid-vapor phase boundary. The entire shock-and-release thermodynamic path must be calculated accurately in order to predict the post-impact structures of planetary bodies. Forsterite (Mg2SiO4) is a commonly used mineral to represent the mantles of differentiated bodies in hydrocode models of planetary collisions. Here, we performed shock experiments on the Sandia Z Machine to obtain the density and temperature of the liquid branch of the liquid-vapor phase boundary of forsterite. This work is combined with previous work constraining pressure, density, temperature, and entropy of the forsterite principal Hugoniot. We find that the vapor curves in previous forsterite equation of state models used in giant impacts vary substantially from our experimental results, and we compare our results to a recently updated equation of state. We have also found that due to under-predicted entropy production on the principal Hugoniot and elevated temperatures of the liquid vapor phase boundary of these past models, past impact studies may have underestimated vapor production. Furthermore, our results provide experimental support to the idea that giant impacts can transform much of the mantles of rocky planets into supercritical fluids.

The use of wide-band transmittance imaging to size and classify suspended particulate matter in seawater.

An in situ particle imaging system for measurement of high concentrations of suspended particles ranging from 30µm to several mm in diameter, is presented. The system obtains quasi-silhouettes of particles suspended within an open-path sample volume of up to 5cm in length. Benchmarking against spherical standards and the LISST-100 show good agreement, providing confidence in measurements from the system when extending beyond the size, concentration and particle classification capabilities of the LISST-100. Particle-specific transmittance is used to classify particle type, independent of size and shape. This is applied to mixtures of oil droplets, gas bubbles and oil-coated gas bubbles, to provide independent measures of oil and gas size distributions, concentrations, and oil-gas ratios during simulated subsea releases. The system is also applied to in situ measurements of high concentrations of large mineral flocs surrounding a submarine mine tailings placement within a Norwegian Fjord.

The Late Electrophysiological Consequences Of Posterior Wall Isolation In Patients With Atrial Fibrillation.

INTRODUCTION: There are many different lesion sets that are used for the surgical ablation of atrial fibrillation (AF). One such pattern is the 'box set', a single ring of scar delivered anterior to the pulmonary veins, which aims to electrically isolate the posterior wall from the rest of the heart. However it remains unclear whether posterior wall isolation (PWI) is an effective lesion set for maintenance of sinus rhythm and whether it is necessary to achieve complete bidirectional block. We investigated the long-term integrity of the 'box set' lesion created during surgical AF ablation by epicardial High Intensity Focussed Ultrasound (HIFU). All patients had documented persistent or recurrent paroxysmal AF prior to surgery. We correlated this with subsequent success or failure in the abolition of atrial fibrillation. METHODS: With regional ethical and R&D approval, 101 patients who had previously undergone HIFU AF ablation greater than 4 years ago were screened for inclusion in the study. 17 patients agreed to late electrophysiological study: 11 with on-going AF and 6 in normal sinus rhythm. Clinical history and 7-day holters were used to define the NSR group. We performed a diagnostic EP study using a transseptal approach in fully anticoagulated patients (INR>2.0 and ACT maintained at >300s). A catheter was placed in the coronary sinus (CS) and a circular multipolar mapping catheter was used to map the left atrium and pulmonary veins. Patients in atrial fibrillation were cardioverted. We recorded whether posterior wall (PW) and pulmonary vein (PV) isolation had been achieved at the surgical procedure. In selected cases we recorded a voltage map using either CARTO (Biosense- Webster) or NavX (St Jude Medical) to identify areas of ablation scar. RESULTS: All 11 patients with AF had absence of PW+PV isolation with fractionated electrograms recorded across the PW. In the 6 patients with long-term freedom from AF, PW+PV isolation was confirmed in 4 (67%) and in 1 there was prolonged conduction across the box-set lesion with CS to PW activation time of around 200ms versus 45ms from mid-CS to left atrial appendage. Of the 4 patients with confirmed PW+PV isolation, 1 had dissociated spontaneous atrial potentials within the box set area and the other 3 had electrical silence throughout with inability to capture the posterior wall pacing at 10mA at multiple sites. CONCLUSIONS: There appears to be a clear correlation between the successful restoration of long-term sinus rhythm and isolation / delayed conduction from the pulmonary veins and posterior wall. Given the advent of hybrid atrial fibrillation ablation techniques designed to deliver this lesion set, these findings are timely and highly relevant.

TAP2D is associated with HLA-B44 and DR4 and may contribute to rheumatoid arthritis and Felty's syndrome susceptibility.

OBJECTIVES: TAP2 transporter gene polymorphisms have been ascertained in patients with rheumatoid arthritis (RA) and Felty's syndrome (FS) to determine whether particular alleles of this gene are disease associated. METHODS: TAP2 dimorphisms at amino acid positions 379, 565 and 665 were detected using ARMS-PCR in 89 RA patients, 24 FS patients and 64 control subjects. TAP 2 alleles were assigned from these results. RESULTS: The frequency of one particular allele, TAP2D, was increased in both RA (OR 2.6, 95% CI 1.2 - 5.8) and FS (OR 3.9, 95% CI 1.4 - 10.7). When individual amino acid polymorphisms were compared between patients and controls, isoleucine at position 379 (present in TAP2D and TAP2C) was significantly increased, indicating that this dimorphism itself may be associated with RA (OR 5.0, 95% CI 2.4 - 10.2) and FS (OR 5.0, 95% CI 1.91 - 3.2). DISCUSSION: The presence of TAP2D was greatly increased in HLA-B44/DR4 positive RA (83%) and FS (67%) patients. These frequencies were appreciably higher than in the HLA-B44/DR4 controls (11%), suggesting that linkage disequilibrium alone may not explain the increase in TAP2D frequency in patients and that this allele may represent an additional risk factor in these conditions.

Tap gene associations in UK caucasoids.

The authors determined the allele frequencies of the TAP1 and TAP2 transporter genes in a healthy UK Caucasoid population by ARMS-PCR. TAP1A was the most frequent TAP1 allele by far, being present in 76% of subjects. TAP1 alleles could not be assigned in 24% of subjects, since the combinations TAP1A/1b and TAP1C/1D cannot be separated. TAP2A was the most frequent TAP2 alleles (75% of subjects) followed by TAP2B (43%), TAP2C (11%), TAP2D (8%) and TAP2E (6%). The authors also identified an individual with a previously undescribed TAP2 allele, TAP2H (isoleucine at amino acid [aa] 379, alanine at aa 565, alanine at aa 665). It was not possible to assign unequivocally TAP2 alleles in 15 individuals (9%) as TAP2A/D and TAP2C/E cannot be distinguished from each other. To address this problem a separate study of families of rheumatoid arthritis (RA) patients selected for this ambiguity were studied. In all five informative families, TAP2A/2D was confirmed as the combination present. In the population studied no evidence was found for linkage disequilibrium between TAP1 and TAP2 or between the TAP genes and HLA-DP. There was no evidence for extensive linkage disequilibrium between the TAP genes and HLA-DQR, although TAP2B was associated with DRI (delta = 0.056, corrected P < 0.01) and TAP2D with DR4 (delta = 0.018). In the RA families studied, TAP2D was found on DRB1*0401-bearing haplotypes.

Increased frequency of TAP2B in early onset pauciarticular juvenile chronic arthritis.

OBJECTIVES: To determine whether polymorphisms of the TAP genes, which lie within the major histocompatibility complex (MHC), are associated with juvenile chronic arthritis (JCA). METHODS: Eighty five JCA patients and 166 white controls were typed for the TAP gene alleles using ARMS-PCR. The same populations were analysed for DRB1 and DPB1 alleles using PCR-SSO typing. RESULTS: TAP2B was increased in early onset pauciarticular JCA (EOPA-JCA) compared with controls (62% v 44% Odds ratio (OR) 2.1, 95% CI 0.9-4.7). After allowing for the known linkage disequilibrium between TAP2B and DR1 the association of TAP2B and EOPA-JCA was maintained (OR 3.5, 95% CI 1.3-9.7). HLA-DRB1*04 and TAP2D were found to be in linkage disequilibrium in both the control (delta 0.018 p < 0.05) and JCA patient groups (delta 0.021 p < 0.05). No linkage disequilibrium was found between the TAP and DPB1 alleles. CONCLUSIONS: The association between TAP2B and EOPA-JCA is a further indication of the heterogeneity which exists in this clinically defined subgroup of patients.

Heparan sulfate proteoglycans and cancer.

Heparan sulfate proteoglycans (HSPGs) are widely distributed in mammalian tissues and involved in a number of processes related to malignancy. They are composed of a core protein to which chains of the glycosaminoglycan, heparan sulfate (HS), are attached. The existence of various classes of core protein, in addition to highly polymorphic HS chains, creates a superfamily of macromolecules with considerable diversity of structure and function. HSPGs interact with many proteins including growth factors, chemokines and structural proteins of the extracellular matrix to influence cell growth, differentiation, and the cellular response to the environment. The recent identification of two inherited syndromes that are associated with an increased cancer risk, and caused by mutations in HSPG-related genes, has intensified interest in these molecules. This review describes our current understanding of HSPGs in cancer and highlights new possibilities for therapeutic control.

Mannose-binding protein gene polymorphism in systemic lupus erythematosus.

OBJECTIVE: To determine whether an allelic form of mannose-binding protein (MBP) incapable of activating complement is associated with susceptibility to systemic lupus erythematosus (SLE). METHODS: MBP allele frequencies were determined by amplification refractory mutation system-polymerase chain reaction in 102 white SLE patients and 136 controls. RESULTS: The MBP allele that is unable to activate complement was present in 42 SLE patients (41%) and in 41 controls (30%) (P = 0.08, odds ratio [OR] = 1.6, 95% confidence interval [95% CI] 1.0-2.8). The gene frequency of this allele was 0.25 in SLE patients and 0.19 in controls (P = 0.08, OR = 1.5, 95% CI 1.0-2.3). CONCLUSION: Our results suggest that this allele of the MBP gene represents a minor risk factor for SLE.

Absence of TAP 2D in Yoruba Nigerians.

We have characterized TAP allele frequencies in a panel of 71 Yoruba Nigerians using ARMS-PCR. With the exception that TAP 2D was absent in Nigerians, TAP 2 allele frequencies in this population were found to be similar to those in a UK white population. HLA-DR4 also was found to be at a low frequency in Yoruba Nigerians (1.4%). This may reflect the absence of TAP 2D in Nigerians as DR4 and TAP 2D are in linkage disequilibrium in UK Caucasoids. The most frequent TAP 1 allele in Yoruba Nigerians was TAP 1A (49%). However, this value will be an underestimate as TAP1 alleles could not be unequivocally assigned in 41% of subjects using the ARMS-PCR methodology.

Polymorphisms of the TAP2 transporter gene in systemic lupus erythematosus.

OBJECTIVES: To determine whether the TAP2 transporter gene, which lies between HLA-DP and HLA-DQ, is involved in determining susceptibility to systemic lupus erythematosus (SLE). METHODS: TAP2 types were determined by ARMS-PCR in 89 white patients with SLE and 156 control subjects. RESULTS: No particular TAP2 dimorphism or allele was associated with SLE or with any clinical/immunological subgroup of SLE. Furthermore, there was no evidence for significant linkage disequilibrium between TAP2 and HLA-DQ/DR in SLE. CONCLUSIONS: These data suggest that TAP2 is not a disease susceptibility gene for SLE and that the disease-predisposing haplotypes do not extend as far as TAP2. This indicates that any HLA-DP association with SLE must be independent of other class II (DQ/DR) associations.

TNF microsatellite a2, b3 and d2 alleles are associated with systemic lupus erythematosus.

We have investigated TNF microsatellite polymorphisms in SLE and their association with both HLA class II alleles and disease expression. A total of 91 Caucasoid SLE and 109 matched Caucasoid controls were recruited for this study. TNF microsatellites a, b and d were typed using fluorescent based semi-automated gene scanning. TNF a2, b3 and d2 allele frequencies were significantly increased in the SLE group compared to controls. These alleles were found to be part of an extended HLA-DRB1*0301 haplotype and have previously been associated with high TNF-alpha production. When the SLE group was analyzed according to presentation of certain clinical features, photosensitivity and Raynaud's phenomenon, the frequency of these alleles (TNF a2, b3 and d2) were also significantly increased. No significant increase in the allele frequencies of TNF a2, b3 and d2 was demonstrated in the group of patients with renal involvement. These data suggest that TNF microsatellite alleles are not independent of HLA associations in SLE and may be important in the expression of certain clinical features in SLE.