openFrame: A modular, sustainable, open microscopy platform with single-shot, dual-axis optical autofocus module providing high precision and long range of operation.

'openFrame' is a modular, low-cost, open-hardware microscopy platform that can be configured or adapted to most light microscopy techniques and is easily upgradeable or expandable to multiple modalities. The ability to freely mix and interchange both open-source and proprietary hardware components or software enables low-cost, yet research-grade instruments to be assembled and maintained. It also enables rapid prototyping of advanced or novel microscope systems. For long-term time-lapse image data acquisition, slide-scanning or high content analysis, we have developed a novel optical autofocus incorporating orthogonal cylindrical optics to provide robust single-shot closed-loop focus lock, which we have demonstrated to accommodate defocus up to ±37 µm with <200 nm accuracy, and a two-step autofocus mode which we have shown can operate with defocus up to ±68 µm. We have used this to implement automated single molecule localisation microscopy (SMLM) in a relatively low-cost openFrame-based instrument using multimode diode lasers for excitation and cooled CMOS cameras.

Circulating mesenchymal stem cells.

Mesenchymal precursor cells (MPCs) are multipotent cells capable of differentiating into various mesenchymal tissues, such as bone, cartilage, fat, tendon and muscle. They are present within both mesenchymal tissues and the bone marrow (BM). If marrow-derived MPCs are to have a role in repair and fibrosis of mesenchymal tissues, transit of these cells through the peripheral blood is to be expected. Although there is evidence for the existence of MPCs within the peripheral blood, results are debated and are not always reproducible. Variations in the methods of cell purification, culture and characterisation may explain the inconsistent results obtained in different studies.

A tumour that secretes glucagon-like peptide-1 and somatostatin in a patient with reactive hypoglycaemia and diabetes.

Glucagon-like peptide 1 (GLP-1), an insulinotropic hormone normally synthesised in the intestinal mucosa and released in response to a meal, is essential for normal glucose homoeostasis. There is much interest in the use of GLP-1 to treat diabetes, since the risk of hypoglycaemia is thought to be low. We report an instance of a 45-year-old woman with a GLP-1 and somatostatin secreting neuroendocrine tumour who presented with reactive hypoglycaemia and hyperglycaemia, but who was subsequently cured by surgery. This case, of a neuroendocrine tumour secreting GLP-1 and causing reactive hypoglycaemia, indicates a potential adverse effect of GLP-1 therapy for diabetes.