Cell Migration in the Immune System: the Evolving Inter-Related Roles of Adhesion Molecules and Proteinases

Leukocyte extravasation into perivascular tissue during inflammation and lymphocyte homing to lymphoid organs involve transient adhesion to the vessel endothelium, followed by transmigration through the endothelial cell (EC) layer and establishment of residency at the tissue site for a period of time. In these processes, leukocytes undergo multiple attachments to, and detachments from, the vessel-lining endothelial cells, prior to transendothelial cell migration. Transmigrating leukocytes must traverse a subendothelial basement membrane en route to perivascular tissues and utilize enzymes known as matrix metalloproteinases to make selective clips in the extracellular matrix components of the basement membrane. This review will focus on the evidence for a link between adhesion of leukocytes to endothelial cells, the induction of matrix metalloproteinases mediated by engagement of adhesion receptors on leukocytes, and the ability to utilize these matrix metalloproteinases to facilitate leukocyte invasion of tissues. Leukocytes with invasive phenotypes express high levels of MMPs, and expression of MMPs enhances the migratory and invasive properties of these cells. Furthermore, MMPs may be used by lymphocytes to proteolytically cleave molecules such as adhesion receptors and membrane bound cytokines, increasing their efficiency in the immune response. Engagement of leukocyte adhesion receptors may modulate adhesive (modulation of integrin affinities and expression), synthetic (proteinase induction and activation), and surface organization (clustering of proteolyric complexes) behaviors of invasive leukocytes. Elucidation of these pathways will lead to better understanding of controlling mechanisms in order to develop rational therapeutic approaches in the areas of inflammation and autoimmunity

Фото и спектральный флуоресцентный анализ области травмы спинного мозга на животных моделях

The purpose of the work is to follow the dynamics of changes in fluorescent signals in the near-surface layers of tissue of injured areas of the back of laboratory animals, which will allow, by indirect evidence, to evaluate the information content of fluorescence diagnosis for subsequent possible diagnostic monitoring of photodynamic therapy of the spinal cord. The model animals were Wistar rats. Two types of contusions were modeled: pneumo-contusion and contusion by a falling load. Methylene blue and indocyanine green were used as photosensitizers. Fluorescence measurements were carried out by imaging and spectrometric methods. A stroboscopic fluorescence imager with an excitation wavelength of 630 nm was used to acquire fluorescence images. The LESA-01-BIOSPEC  spectrometer with a He-Ne laser excitation allowed to obtain spectra. It was shown that both methods make it possible to estimate the fluorescence value of methylene blue and indocyanine green in the tissues under study. Moreover, the photographic method also allows to obtain the spatial distribution of fluorescence. The general trend found in the data is a more intense and uniform fluorescence of the dorsal region of rats with methylene blue and a less intense, but more contrasting distribution of indocyanine green. The presented methods are non-invasive, which makes them attractive for diagnostic use. However, due to the shallow depth of signal reception, the condition of the spine can be determined only indirectly, by the condition of the near-surface layers of tissue that accumulate the photosensitizer.Цель работы – проследить  динамику изменения флуоресцентных  сигналов  в приповерхностных слоях  тканей  травмированных участков спины лабораторных животных, что позволит, по косвенным признакам, оценить информативность флуоресцентной диагностики для последующего возможного диагностического мониторинга фотодинамической терапии спинного мозга. Модельными животными были крысы Вистар. Моделировалось два типа контузий: пневмоконтузия и контузия падающим грузом. Флуоресцентные измерения  проводились  фотографическим   и  спектрометрическим   методом с  препаратами  метиленовый  синий  и  индоцианин зеленый. Для фоторегистрации  флуоресцентного  ответа  использовался  стробоскопический флуоресцентный  имиджер с длиной волны возбуждения 630 нм. Спектральные  измерения проводились  с помощью спектрометра  ЛЕСА-01-БИОСПЕК, с возбуждением He-Ne  лазером  (632,8 нм). Показано,  что  оба  метода  позволяют  оценивать  величину  флуоресценции  метиленового  синего  и индоцианина зелёного в исследуемых тканях, а фотографический метод позволяет также получить пространственное распределение флуоресценции. Общая тенденция, обнаруженная в полученных данных – более интенсивная и равномерная флуоресценции дорсальной области крыс метиленовым синим, и менее интенсивное, но более контрастное распределение индоцианина зелёного. Представленные методы неинвазивны, что делает их привлекательными для диагностического использования. Однако из-за малой глубины приема сигнала состояние позвоночника можно определить лишь косвенно, по состоянию приповерхностных слоев тканей, накапливающих фотосенсибилизатор

Risk of hydroxychloroquine alone and in combination with azithromycin in the treatment of rheumatoid arthritis: a multinational, retrospective study

Background: Hydroxychloroquine, a drug commonly used in the treatment of rheumatoid arthritis, has received much negative publicity for adverse events associated with its authorisation for emergency use to treat patients with COVID-19 pneumonia. We studied the safety of hydroxychloroquine, alone and in combination with azithromycin, to determine the risk associated with its use in routine care in patients with rheumatoid arthritis. Methods: In this multinational, retrospective study, new user cohort studies in patients with rheumatoid arthritis aged 18 years or older and initiating hydroxychloroquine were compared with those initiating sulfasalazine and followed up over 30 days, with 16 severe adverse events studied. Self-controlled case series were done to further establish safety in wider populations, and included all users of hydroxychloroquine regardless of rheumatoid arthritis status or indication. Separately, severe adverse events associated with hydroxychloroquine plus azithromycin (compared with hydroxychloroquine plus amoxicillin) were studied. Data comprised 14 sources of claims data or electronic medical records from Germany, Japan, the Netherlands, Spain, the UK, and the USA. Propensity score stratification and calibration using negative control outcomes were used to address confounding. Cox models were fitted to estimate calibrated hazard ratios (HRs) according to drug use. Estimates were pooled where the I2 value was less than 0·4. Findings: The study included 956 374 users of hydroxychloroquine, 310 350 users of sulfasalazine, 323 122 users of hydroxychloroquine plus azithromycin, and 351 956 users of hydroxychloroquine plus amoxicillin. No excess risk of severe adverse events was identified when 30-day hydroxychloroquine and sulfasalazine use were compared. Self-controlled case series confirmed these findings. However, long-term use of hydroxychloroquine appeared to be associated with increased cardiovascular mortality (calibrated HR 1·65 [95% CI 1·12–2·44]). Addition of azithromycin appeared to be associated with an increased risk of 30-day cardiovascular mortality (calibrated HR 2·19 [95% CI 1·22–3·95]), chest pain or angina (1·15 [1·05–1·26]), and hear

On The Boolean Algebra of Shape Analysis Constraints

Shape analysis is a promising technique for statically verifyingand extracting properties of programs that manipulatecomplex data structures. We introduce a new characterizationof constraints that arise in parametric shapeanalysis based on manipulation of three-valued structuresas dataflow facts.We identify an interesting syntactic class of first-orderlogic formulas that captures the meaning of three-valuedstructures under concretization. This class is broader thanpreviously introduced classes, allowing for a greater flexibilityin the formulation of shape analysis constraints inprogram annotations and internal analysis representations.Three-valued structures can be viewed as one possible normalform of the formulas in our class.Moreover, we characterize the meaning of three-valuedstructures under Âtight concretizationÂ. We show that theseemingly minor change from concretization to tight concretizationincreases the expressive power of three-valuedstructures in such a way that the resulting constraints areclosed under all boolean operations. We call the resultingconstraints boolean shape analysis constraints.The main technical contribution of this paper is a naturalsyntactic characterization of boolean shape analysis constraintsas arbitrary boolean combinations of first-order sentencesof certain form, and an algorithm for transformingsuch boolean combinations into the normal form that correspondsdirectly to three-valued structures.Our result holds in the presence of arbitrary shape analysisinstrumentation predicates. The result enables the reduction(without any approximation) of the entailment andthe equivalence of shape analysis constraints to the satisfiabilityof shape analysis constraints. When the satisfiabilityof the constraints is decidable, our result implies that theentailment and the equivalence of the constraints are alsodecidable, which enables the use of constraints in a compositionalshape analysis with a predictable behavior

Abstracting Call-Stacks for Interprocedural Verification of Imperative Programs

We address in this paper the verification of imperative programs with recursion. Our approach consists in using abstract interpretation to relate the standard semantics of imperative programs to an abstract semantics, by the mean of a Galois connection, and then to resort to intraprocedural techniques, which can be applied on the abstract semantics. This approach allows the reuse of classical intraprocedural techniques with few modifications, generalises existing approaches to interprocedural analysis and offers additional flexibility, as it keeps substantial information on the call-stack of the analysed program