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The Variable Quality of Metadata About Biological Samples Used in Biomedical Experiments

arXiv.org Artificial Intelligence

We present an analytical study of the quality of metadata about samples used in biomedical experiments. The metadata under analysis are stored in two well- known databases: BioSample---a repository managed by the National Center for Biotechnology Information (NCBI), and BioSamples---a repository managed by the European Bioinformatics Institute (EBI). We tested whether 11.4M sample metadata records in the two repositories are populated with values that fulfill the stated requirements for such values. Our study revealed multiple anomalies in the metadata. Most metadata field names and their values are not standardized or controlled. Even simple binary or numeric fields are often populated with inadequate values of different data types. By clustering metadata field names, we discovered there are often many distinct ways to represent the same aspect of a sample. Overall, the metadata we analyzed reveal that there is a lack of principled mechanisms to enforce and validate metadata requirements. The significant aberrancies that we found in the metadata are likely to impede search and secondary use of the associated datasets.


Image-based phenotyping of disaggregated cells using deep learning

#artificialintelligence

The ability to phenotype cells is fundamentally important in biological research and medicine. Current methods rely primarily on fluorescence labeling of specific markers. However, there are many situations where this approach is unavailable or undesirable. Machine learning has been used for image cytometry but has been limited by cell agglomeration and it is currently unclear if this approach can reliably phenotype cells that are difficult to distinguish by the human eye. Here, we show disaggregated single cells can be phenotyped with a high degree of accuracy using low-resolution bright-field and non-specific fluorescence images of the nucleus, cytoplasm, and cytoskeleton. Specifically, we trained a convolutional neural network using automatically segmented images of cells from eight standard cancer cell-lines. These cells could be identified with an average F1-score of 95.3%, tested using separately acquired images. Our results demonstrate the potential to develop an “electronic eye” to phenotype cells directly from microscopy images. Berryman et al demonstrate that disaggregated cells can be phenotyped with a high degree of accuracy from bright-field and non-specifically stained microscopy images using a trained convolutional neural network (CNN). This approach allows for the identification of cell types without the need for specific markers.


Classifying and Segmenting Microscopy Images Using Convolutional Multiple Instance Learning

arXiv.org Machine Learning

Convolutional neural networks (CNN) have achieved state of the art performance on both classification and segmentation tasks. Applying CNNs to microscopy images is challenging due to the lack of datasets labeled at the single cell level. We extend the application of CNNs to microscopy image classification and segmentation using multiple instance learning (MIL). We present the adaptive Noisy-AND MIL pooling function, a new MIL operator that is robust to outliers. Combining CNNs with MIL enables training CNNs using full resolution microscopy images with global labels. We base our approach on the similarity between the aggregation function used in MIL and pooling layers used in CNNs. We show that training MIL CNNs end-to-end outperforms several previous methods on both mammalian and yeast microscopy images without requiring any segmentation steps.


Scientists create revolutionary 'DNA microscope' to peer into human cells at the genetic level

Daily Mail - Science & tech

Remarkable footage shows how a revolutionary technique is letting scientists peer into cells at the genetic level -- both imaging the cell and sequencing its DNA. Unlike traditional microscopes, which use light, the new approach uses DNA'bar codes' to label each molecule in the cell. From readings of the complex interactions of these labels with the molecules and each other, a computer algorithm can work backward to reveal an image of the cell. DNA microscopy could find myriad applications -- including helping scientists study immune cells and tumours to develop new treatments to fight cancer. The unorthodox imaging technique was developed by biophysicist Joshua Weinstein and colleagues at the Broad Institute in Cambridge, Massachusetts.


CytoImageNet: A large-scale pretraining dataset for bioimage transfer learning

arXiv.org Artificial Intelligence

Motivation: In recent years, image-based biological assays have steadily become high-throughput, sparking a need for fast automated methods to extract biologically-meaningful information from hundreds of thousands of images. Taking inspiration from the success of ImageNet, we curate CytoImageNet, a large-scale dataset of openly-sourced and weakly-labeled microscopy images (890K images, 894 classes). Pretraining on CytoImageNet yields features that are competitive to ImageNet features on downstream microscopy classification tasks. We show evidence that CytoImageNet features capture information not available in ImageNet-trained features. The dataset is made available at https://www.kaggle.com/stanleyhua/cytoimagenet.