Identifying Biases in a Multicenter MRI Database for Parkinson's Disease Classification: Is the Disease Classifier a Secret Site Classifier?

Sharing multicenter imaging datasets can be advantageous to increase data diversity and size but may lead to spurious correlations between site-related biological and non-biological image features and target labels, which machine learning (ML) models may exploit as shortcuts. To date, studies analyzing how and if deep learning models may use such effects as a shortcut are scarce. Thus, the aim of this work was to investigate if site-related effects are encoded in the feature space of an established deep learning model designed for Parkinson's disease (PD) classification based on T1-weighted MRI datasets. Therefore, all layers of the PD classifier were frozen, except for the last layer of the network, which was replaced by a linear layer that was exclusively re-trained to predict three potential bias types (biological sex, scanner type, and originating site). Our findings based on a large database consisting of 1880 MRI scans collected across 41 centers show that the feature space of the established PD model (74% accuracy) can be used to classify sex (75% accuracy), scanner type (79% accuracy), and site location (71% accuracy) with high accuracies despite this information never being explicitly provided to the PD model during original training. Overall, the results of this study suggest that trained image-based classifiers may use unwanted shortcuts that are not meaningful for the actual clinical task at hand. This finding may explain why many image-based deep learning models do not perform well when applied to data from centers not contributing to the training set.

The causal link between cardiometabolic risk factors and gray matter atrophy: An exploratory study

Although gray matter atrophy is commonly observed with aging, it is highly variable, even among healthy people of the same age. This raises the question of what other factors may contribute to gray matter atrophy. Previous studies have reported that risk factors for cardiometabolic diseases are associated with accelerated brain aging. However, these studies were primarily based on standard correlation analyses, which do not unveil a causal relationship. While randomized controlled trials are typically required to investigate true causality, in this work, we investigated an alternative method by exploring data-driven causal discovery and inference techniques on observational data. Accordingly, this feasibility study used clinical and quantified gray matter volume data from 22,793 subjects from the UK biobank cohort without any known neurological disease. Our method identified that age, sex, body mass index (BMI), body fat percentage (BFP), and smoking exhibit a causal relationship with gray matter volume. Interventions on the causal network revealed that higher BMI and BFP values significantly increased the chance of gray matter atrophy in males, whereas this was not the case in females.

Extended-volume image-derived models of coronary microcirculation

OBJECTIVE

Recent advances in tissue clearing and high-throughput imaging have enabled the acquisition of extended-volume microvasculature images at a submicron resolution. The objective of this study was to extract information from this type of images by integrating a sequence of 3D image processing steps on Terabyte scale datasets.

METHODS

We acquired coronary microvasculature images throughout an entire short-axis slice of a 3-month-old Wistar-Kyoto rat heart. This dataset covered 13 × 10 × 0.6 mm at a resolution of 0.933 × 0.933 × 1.866 μm and occupied 700 Gigabytes of disk space. We used chunk-based image segmentation, combined with an efficient graph generation technique, to quantify the microvasculature in the large-scale images. Specifically, we focused on the microvasculature with a vessel diameter up to 15 μm.

RESULTS

Morphological data for the complete short-axis ring were extracted within 16 h using this pipeline. From the analyses, we identified that microvessel lengths in the rat coronary microvasculature varied from 6 to 300 μm. However, their distribution was heavily skewed toward shorter lengths, with a mode of 16.5 μm. In contrast, vessel diameters ranged from 3 to 15 μm and had an approximately normal distribution of 6.5 ± 2 μm.

CONCLUSION

The tools and techniques from this study will serve other investigations into the microcirculation, and the wealth of data from this study will enable the analysis of biophysical mechanisms using computer models.

Image-Based Tools and Analysis for Human RVOT/RV Structures

The right-ventricular (RV) outflow tract (RVOT) and the transition to the RV free wall are recognized sources of arrhythmia in human hearts. However, we do not fully understand myocardial tissue structures in this region. Human heart tissue was processed for optical clarity, labelled with wheat-germ agglutin (WGA) and anti-Cx43, and imaged on a custom-built line scanning confocal microscope. The 3D images were analyzed for myocyte gross structures and cell morphology. There were regions of high organization as well as rapid changes to more heterogeneous regions. Preliminary cell segmentations were used to estimate cell morphology. Observed RVOT/RV structure is consistent with known arrhythmic substrates.Clinical Relevance- New views of human tissue structure enable clearer clinical understanding of arrhythmogenic activation pathways and targets for invasive treatment such as RF ablation.

Anti-neoplastic pharmacophore benzophenone-1 coumarin (BP-1C) targets JAK2 to induce apoptosis in lung cancer

Reigning of the abnormal gene activation associated with survival signalling in lung cancer leads to the anomalous growth and therapeutic failure. Targeting specific cell survival signalling like JAK2/STAT3 nexus has become a major focus of investigation to establish a target specific treatment. The 2-bromobenzoyl-4-methylphenoxy-acetyl hydra acetyl Coumarin (BP-1C), is new anti-neoplastic agent with apoptosis inducing capacity. The current study was aimed to develop antitumor phramacophore, BP-1C as JAK2 specific inhibitor against lung neoplastic progression. The study validates and identifies the molecular targets of BP-1C induced cell death. Cell based screening against multiple cancer cell lines identified, lung adenocarcinoma as its specific target through promotion of apoptosis. The BP-1C is able to induce, specific hall marks of apoptosis and there by conferring anti-neoplastic activity. Validation of its molecular mechanism, identified, BP-1C specifically targets JAK2^Tyr1007/1008 phosphorylation, and inhibits its downstream STAT3^Tyr705 signalling pathway to induce cell death. As a consequence, modulation in Akt/Src survival signal and altered expression of interwoven apoptotic genes were evident. The results were reproducible in an in-vivo LLC tumor model and in-ovo xenograft studies. The computational approaches viz, drug finger printing confers, BP-1C as novel class JAK2 inhibitor and molecular simulations studies assures its efficiency in binding with JAK2. Overall, BP-1C is a novel JAK2 inhibitor with experimental evidence and could be effectively developed into a promising drug for lung cancer treatment.

The tumor antagonistic steroidal alkaloid Solanidine prompts the intrinsic suicidal signal mediated DFF-40 nuclear import and nucleosomal disruption

Aim Deformity in the cellular homeostatic event associated with cell survival and apoptosis are committing factors for carcinogenesis. Interventions of these events by pharmacologically active agent gain predominance in cancer treatment. In current investigation Solanidine, a steroidal alkaloid was evaluated on tumorigenesis by targeting death signal using multiple tumor cells and model systems.

MAIN METHODS

Anti-proliferative effect was evaluated using cytotoxic studies. Prolonged cytotoxic effect of Solanidine was examined by colony formation assay. Exhibition of apoptotic hallmark induced by Solanidine was examined using FACS analysis, Annexin-V staining, Acridine orange staining, TUNEL assay. Altered gene expression was evaluated using Immunoblot, Immunofluorescence and Immunohistochemistry technique. In-vitro results were revalidated in EAC solid tumor and CAM xenograft model.

KEY FINDINGS

Solanidine exerts its potential effect in a target specific manner. The cytotoxic/anticlonogenic activity was due to induction of typical cellular apoptotic hallmarks and cell cycle blockage at S-G2/M phase. The molecular events underlying this effect is through activation of intrinsic pathway via Bax, Bad and Cytochrome c activation by neutralizing Bcl-2 expression, along with downregulated PI3K/Akt survival signal. As a consequence, downstream pro apoptogenic gene, active Caspase-3 was over expressed by Solanidine to cleave its substrate PARP and promotes nuclear import of DFF-40. Anti-carcinogenic aptitude was further confirmed by murine solid tumors and in-vivo CAM xenograft studies.

SIGNIFICANCE

Solanidine emerged as active molecule against tomorigenesis by activating nuclear import of DFF-40 mediated nucleosomal disruption and cell demise. It can be developed as a potential apoptogenic small molecule for cancer therapy.

Immunomodulatory glc/man-directed Dolichos lablab lectin (DLL) evokes anti-tumour response in vivo by counteracting angiogenic gene expressions

Neovascularization and jeopardized immunity has been critically emphasized for the establishment of malignant progression. Lectins are the diverse class of carbohydrate interacting proteins, having great potential as immunopotentiating and anti-cancer agents. The present investigation sought to demonstrate the anti-proliferative activity of Dolichos lablab lectin (DLL) encompassing immunomodulatory attributes. DLL specific to glucose and mannose carbohydrate moieties has been purified to homogeneity from the common dietary legume D. lablab. Results elucidated that DLL agglutinated blood cells non-specifically and displayed striking mitogenicity to human and murine lymphocytes in vitro with interleukin (IL)-2 production. The DLL-conditioned medium exerted cytotoxicity towards malignant cells and neoangiogenesis in vitro. Similarly, in-vivo anti-tumour investigation of DLL elucidated the regressed proliferation of ascitic and solid tumour cells, which was paralleled with blockade of tumour neovasculature. DLL-treated mice showed an up-regulated immunoregulatory cytokine IL-2 in contrast to severely declined levels in control mice. Mechanistic validation revealed that DLL has abrogated the microvessel formation by weakening the proangiogenic signals, specifically nuclear factor kappa B (NF-κB), hypoxia inducible factor 1α (HIF-1 α), matrix metalloproteinase (MMP)-2 and 9 and vascular endothelial growth factor (VEGF) in malignant cells leading to tumour regression. In summary, it is evident that the dietary lectin DLL potentially dampens the malignant establishment by mitigating neoangiogenesis and immune shutdown. For the first time, to our knowledge, this study illustrates the critical role of DLL as an immunostimulatory and anti-angiogenic molecule in cancer therapeutics.

Synthesis of novel morpholine conjugated benzophenone analogues and evaluation of antagonistic role against neoplastic development

A series of novel 4-benzyl-morpholine-2-carboxylic acid N'-[2-(4-benzoyl-phenoxy)-acetyl]-hydrazide derivatives 8a-j has been synthesized from (4-hydroxy-aryl)-aryl methanones through a multi-step reaction sequence and then evaluated for anti-proliferative activity in vitro against various types of neoplastic cells of mouse and human such as DLA, EAC, MCF-7 and A549 cells. From the cytotoxic studies and structural activity relationship of compounds 8a-j, it is clear that methyl group on the B ring of benzophenone is essential for antiproliferative activity and bromo at ortho position (compound 8b) and methyl at para position (compound 8f) on A ring of benzophenone are significant for extensive anti-mitogenic activity. Investigation on clonogenesis and Fluorescence-activated cell sorting suggests that compounds 8b and 8f have the potency to exhibit the prolonged activity with cell cycle arrest on G2/M phase against cancer progression. Further, the compounds 8b and 8f inhibit murine ascites lymphoma through caspase activated DNase mediated apoptosis.

BP-1T, an antiangiogenic benzophenone-thiazole pharmacophore, counteracts HIF-1 signalling through p53/MDM2-mediated HIF-1α proteasomal degradation

Hypoxia is a feature of all solid tumours, contributing to tumour progression. Activation of HIF-1α plays a critical role in promoting tumour angiogenesis and metastasis. Since its expression is positively correlated with poor prognosis for cancer patients, HIF-1α is one of the most convincing anticancer targets. BP-1T is a novel antiproliferative agent with promising antiangiogenic effects. In the present study, the molecular mechanism underlying cytotoxic/antiangiogenic effects of BP-1T on tumour/non-tumour angiogenesis was evaluated. Evidences show that BP-1T exhibits potent cytotoxicity with prolonged activity and effectively regressed neovessel formation both in reliable non-tumour and tumour angiogenic models. The expression of CoCl₂-induced HIF-1α was inhibited by BP-1T in various p53 (WT)-expressing cancer cells, including A549, MCF-7 and DLA, but not in mutant p53-expressing SCC-9 cells. Mechanistically, BP-1T mediates the HIF-1α proteasomal degradation by activating p53/MDM2 pathway and thereby downregulated HIF-1α-dependent angiogenic genes such as VEGF-A, Flt-1, MMP-2 and MMP-9 under hypoxic condition of in vitro and in vivo solid tumour, eventually leading to abolition of migration and invasion. Based on these observations, we conclude that BP-1T acts on HIF-1α degradation through p53/MDM2 proteasome pathway.

Therapeutic potential of Polyalthia cerasoides stem bark extracts against oxidative stress and nociception

BACKGROUND

Polyalthia cerasoides is a medicinal plant known for its ethnopharmacological importance. Despite this, investigation related to its therapeutic benefit is still unexplored.

AIM

To evaluate the stem bark extracts of Polyalthia cerasoides for pharmacological activities relating to inflammation, nociception and oxidative stress using in vivo and in vitro models.

MATERIALS AND METHODS

Pet ether, ethyl acetate and chloroform fractions of the stem bark were evaluated for anti-inflammatory activity by carrageenan-induced hind paw edema in rats. Anti-nociceptive activity in mice was assessed using thermally and chemically induced analgesic models. The free radical quenching potential of the extracts was initially analyzed using the in vitro DPPH photometric assay, Hydroxyl radical scavenging and Lipid Peroxidation assays. Then modulatory effect of the extracts on in vivo antioxidant system was evaluated by carbon tetrachloride induced hepatotoxicity and subsequent measurements of antioxidant enzymes such as Superoxide dismutase, Catalase and Peroxidase from the liver homogenate.

RESULTS

Among the tested fractions, ethyl acetate extract had substantially inhibited the inflammation by 68.5% that was induced by subcutaneous carrageenan injection whereas pet ether and chloroform extract showed only minimal inhibitory effect. Investigation of the anti-nociceptive activity revealed that the ethyl acetate fractions had significantly repressed the algesia in both the analgesic experimental models. In vitro and in vivo individual antioxidant assays demonstrated that the ethyl acetate fraction has strong free radical quenching potential which also restores the endogenous hepatic enzymes.

CONCLUSION

The ethyl acetate fraction enriched with flavinoids and steroids from Polyalthia cerasoides stem bark has potent bioactivity to combat inflammation, ROS and pain. This needs further characterization for potential therapeutic applications.

Pharmacological Potential of Tetrahydrofurano/Pyrano Quinoline and Benzo[b]furoindolyl Derivatives in Acute Inflammation, Pain and Oxidative Stress

OBJECTIVE

Investigation of the pharmacological potential of Tetrahydrofurano/pyrano quinoline and Benzo [b]furoindolyl derivatives in acute inflammation, pain and oxidative stress.

METHODS

Tetrahydrofurano/ pyrano quinoline and Benzo[b]furoindolyl were evaluated for anti-inflammatory activity by carrageenan-induced hind paw edema in rats. Analgesic activity in mice was assessed by both peripheral and central analgesic models. The free radical scavenging activity of the synthetic compound was analyzed by the in vivo antioxidant assays, by measuring the antioxidant enzymes such as Superoxide dismutase (SOD), Catalase and Peroxidase from the liver homogenate and the in vitro antioxidant activity was evaluated by DPPH photometric assay, Hydroxyl radical scavenging and Lipid Peroxidation assay.

RESULTS

The compounds had substantially inhibited the inflammation induced by subcutaneous carrageenan injection. The same compounds had demonstrated remarkable central and peripheral analgesic activity with potent free radical scavenging activity as evident from both in vitro and in vivo antioxidant assays.

CONCLUSION

Tetrahydrofurano/pyrano quinoline and Benzo[b]furoindolyl derivatives exhibit varied pharmacological activities that include anti-inflammatory, analgesic and antioxidant activity.