ALBERT

Description: 〈span〉〈div〉Abstract〈/div〉Exceptional sub-micrometer details of shell microstructure are preserved in phosphatic micro-steinkerns representing several phyla from shell beds of the Upper Ordovician of the Cincinnati Arch region, USA. These fossils provide the most detailed record of Ordovician mollusk shell microstructures, as well as exceptional details on the earliest cases of undisputed nacre. The trend towards nacre in the Mollusca is one aspect of the surge in escalation between mollusks and their predators during the Great Ordovician Biodiversification Event.〈/span〉

Description: Background: After long-term treatment with tyrosine kinase inhibitors (TKIs), an important proportion of patients with chronic myeloid leukemia (CML) achieve and maintain a deep molecular response (DMR) that allows them to stop treatment indefinitely. However, approximately 50% of these patients on treatment-free remission (TFR) experience relapse by undetermined reasons. It has been described that TKIs may induce a potent antileukemic response that conditions the outcome of the discontinuation. Our objective was to analyze different immune parameters that could be used as biomarkers of safer treatment discontinuation. Objectives: To determine the modulation of immune biomarkers that could be related to current treatment with TKIs on patients with CML ("On TKI") or to successful TFR in patients that maintain DMR after treatment withdrawal ("Off TKI") or to relapse after TFR on patients that lost DMR. Materials & methods: We analyzed by flow cytometry the peripheral blood mononuclear cells (PBMCs) from 45 patients with CML "On TKI" for at least 9 months (imatinib (11), nilotinib (9), dasatinib (20) or bosutinib (5)), 17 patients "Off TKI" for at least 7 months who kept DMR at the moment of sampling (last TKI before TFR: imatinib (7), nilotinib (6), dasatinib(4)), 7 patients "Off TKI" for at least 1 year and 4 months who relapsed during TFR (samples from 3 patients were taken previous to TKI reintroduction (on relapse); samples from 4 patients were taken after they restarted treatment with TKIs ("On TKI" relapse), 4 patients with recent diagnosis of CML still untreated, and 20 healthy donors as basal control. Results: 1) Patients characteristics are shown in table 1. 2) Treatment with TKIs induced an increase of 8.6±1.2% ((p4%; CD86+

Description: Although it is well established that stromal intercellular adhesion molecule-1 (ICAM-1), ICAM-2, and vascular cell adhesion molecule-1 (VCAM-1) mediate lymphocyte recruitment into peripheral lymph nodes (PLNs), their precise contributions to the individual steps of the lymphocyte homing cascade are not known. Here, we provide in vivo evidence for a selective function for ICAM-1 〉 ICAM-2 〉 VCAM-1 in lymphocyte arrest within noninflamed PLN microvessels. Blocking all 3 CAMs completely inhibited lymphocyte adhesion within PLN high endothelial venules (HEVs). Postarrest extravasation of T cells was a 3-step process, with optional ICAM-1–dependent intraluminal crawling followed by rapid ICAM-1– or ICAM-2–independent diapedesis and perivascular trapping. Parenchymal motility of lymphocytes was modestly reduced in the absence of ICAM-1, while ICAM-2 and α4-integrin ligands were not required for B-cell motility within follicles. Our findings highlight nonredundant functions for stromal Ig family CAMs in shear-resistant lymphocyte adhesion in steady-state HEVs, a unique role for ICAM-1 in intraluminal lymphocyte crawling but redundant roles for ICAM-1 and ICAM-2 in lymphocyte diapedesis and interstitial motility.

Description: INTRODUCTION Transplant-associated thrombotic microangiopathy (TMA) is a severe complication after allogeneic stem cell transplantation (ASCT) due to endothelial injury caused by many factors such Calcineurin-inhibitors. In most severe cases, TMA could affect different organs. Intestinal TMA could be fatal and missdiagnosed in many patients. Clinical and pathological criteria to differentiate from intestinal GVHD are needed in order to distinguish both entities with different therapeutical approach. The aim of this study was to review pathological TMA features in patients diagnosed of systemic TMA . PATIENTS AND METHODS We analyzed the incidence of TMA in 527 pts who underwent ASCT in our institution between jan-2010 and apr-2018. Patients were identified if they had TMA according to probable TMA criteria by Ho. We do a pathological review in 96 samples from 18 of 42 patients in whom an endoscopy have been performed after the diagnosis of the TMA; endoscopy have been performed between 30 days before and 60 days after diagnosis of TMA for initial clinical diagnosis of GVHD. Review was performed by a pathologist expert. He examined the biopsies in search of features of GVHD, TMA or viral infection. Diagnosis of GVHD was stablished according to Mcdonald and Sales criteria, intestinal TMA diagnosis was perfomed by the 8 criteria summarized by Warren et al (perivascular mucosal hemorrhage, endothelial cell swelling, endothelial cell separation, intraluminal schistocytes, fibrin or microthrombi, loss of glands and mucosal denudation). RESULTS Baseline/transplant characteristics of patients with TMA are shown in table 1, TMA data in 2 and review hystological features of biopsies in 3. 45 (8.5%) were diagnosed of TMA with a median time from transplant of 75 days. Median age was 49 (19-69). Prophylaxis of GVHD was: Calcineurin inhibitor-MTX in 16 (35.5%), Tacrolimus-Sirolimus in 21 (46.6%), Tacrólimus-MMF and Cyclophosphamide in 8 (17.6%). 42 (93%) had prior or simultaneous acute GVHD, half of them grade III-IV, and 80% with gastrointestinal GVHD. 42% had elevated levels of tacrolimus and 13.6% elevated levels of sirolimus, one week before the diagnosis of TMA. Gastrointestinal MAT have been reported only in 5 patients (28%) at diagnosis whereas when review based on Warren criteria was performed, in 16 patients (89%) the pathologist found at least 1 of the criteria of endothelial damage and 50 % of the patients met 3 or more Warren criteria. The most frequent features were endothelial cell swelling (13 patients, 73 %) and perivascular mucosal hemorrhage (12 patients, 66.7%). In 3 biopsies which we perfomed the inmunochemistry of C4d, an activation of classic way of complement biomarker, it was positive. 4 of the 18 patients (22.2%) presented refractory-hypertension and 3 of them (26.6%) more than 30 mg/d Lof proteinuria, both suggested of poor prognosis. Regarding GVHD, it was founded in 72% at diagnosis and in all patients (18) at pathological review. 13 had grade I, 1 grade II, 1 grade III and 3 histological grade IV). With a median follow-up of 5 months (2-25) 25 of the 45 (56%) are dead. 6 of the deaths (24%) were related to TMA (1 due to TMA, 3 due to TMA+GVHD, 2 due to TMA+infection). Other causes of death were progression (4), GVHD+Infection (7), GVHD (3), infection (2), sinusoidal obstruction síndrome (1) and other causes (2). CONCLUSION TMA is a frequent complication, related with GVHD and underdiagnosed frequently. Only 5 of 18 patients were diagnosed of gastrointestinal TMA. In our study, we found that most of our patients had endotelial damage in the gastrointestinal biopsy pathological reviews. Although histological criteria of GVHD were present at review, in most of them it was only grade I; it contrasts with the severe clinical features. That lack of correlation would suggest that TMA and not GVHD is the main feature. Management of TMA and GVHD are different. To stress an appropiate diagnosis in gastrointestinal TMA is needed in order to offer the patients the best approach. REFERENCES Warren et al. A Complete Histologic Approach to Gastrointestinal Biopsy From Hematopoietic Stem Cell Transplant Patients With Evidence of Transplant-Associated Gastrointestinal Thrombotic Microangiopathy. Arch Pathol Lab Med.2017 Nov;141(11):1558-1566. Jodele S et al. A new paradigm: Diagnosis and management of HSCT-associated thrombotic microangiopathy as multi-system endothelial injury. Blood Rev. 2015;29(3):191-204. Disclosures No relevant conflicts of interest to declare.

Description: The admission of neutropenic patients (pts) to intensive care units (ICU) is controversial, especially when mechanical ventilation is required. Knowledge of the relative prognostic impact of factors related to the underlying disease and to the severity of acute organ failures might help avoiding futile admissions. We retrospectively assessed predictors of 30-day mortality in neutropenic (500/ul). Pts who died were more likely to have non-M3 AL subtype vs M3 (p=0.037), to have ≥ 2 acute OSF vs 〈 2 (p=0.012) and a higher SAPS II score (p〈 0.001). In multivariate analysis only the latter 2 variables remained significant. In conclusion, our data show that 27% of neutropenic pts admitted to ICUs are alive at 30 days; that selection for admission should not be based on the characteristics of the underlying malignancy; and that the 30-day mortality is highly predictable by initial acute illness severity scores.

Description: Exceptional examples of planispiral ammonites that were infested by epizoans during life display alterations of their normal coiling. Most commonly, the epizoan(s) settled on the venter of the ammonite and constituted an obstacle for the whorl tube grown one whorl later; this caused lateral deviation of the whorl tube and tilting of the ammonoid because of changes in the hydrostatic condition; from here on, the whorl tube periodically crossed the venter of the preceding whorl, thereby producing a zigzag coiling pattern. Some epizoans, which were particularly centered on the midventer, provoked detachment between whorls. In a few cases, lateral placement of the epizoan did not directly obstruct the normal growth path of the ammonite but induced a trochospiral coiling pattern. Both the zigzag and the trochospiral pattern were created when the ammonite tried to maintain the growth direction within the vertical plane at the same time as whorls remained in contact along a differentiated dorsal epithelium. The aperture reacted to changes in growth direction, to maintain also a permanent angle with the vertical direction. Growth direction, then, was a major morphogenetic parameter in ammonites, because it contained the necessary instructions for correct shell coiling. The model based on the observation of fabricational defects has been tested by a theoretical model by which the different situations so far observed are simulated and in which the parameters are the morphogenetic instructions inferred to have been present in the biological system.

Description: The origin of ammonite sutures is one of the most interesting open problems in paleontology. Present theories of suture formation deal with function rather than morphogenesis. Here we present a study showing that sutures are scale-invariant. In each of ten different ammonite genera, the ontogenetic sequence of the suture can be characterized by the same fractal dimension. We propose a morphogenetic theory for ammonite sutures that is based on the similarity between sutures and the Saffman-Taylor instability in both fractal characters and physical mechanism.

Description: Gastropod opercula are classified here on a new morphogenetic basis, which distinguishes three main types: (1) flexiclaudent spiral (mostly multispiral) operculum, the shape of which does not coincide with that of the aperture, (2) rigiclaudent spiral (usually paucispiral) operculum, the shape of which fits that of the aperture, and (3) rigiclaudent concentric operculum, also aperture-fitting. The first type fits by flexing into the aperture and is secreted when the soft parts are partly or wholly extended (i.e., when the operculum is not in a closed position). The other two types do not flex upon retraction (except at the very margin) and grow when the operculum closes over the aperture, with or without rotation. A study of opercular types at the family level confirms the systematic and evolutionary significance of opercula. Types 1 and 2 are the only ones present in archaeogastropods, Type 1 being predominant. Opercula (if present) in Neritopsina are always rigiclaudent. Within Caenogastropoda, Type 2 predominates; the only flexiclaudent spiral opercula are found in certain basal cerithioidean families. Concentric opercula are predominant in higher neotaenioglossans and exclusive in neogastropods. Except for one family, opercula in Heterostropha are always rigiclaudent spiral. Morphological, systematic, and histological criteria point to the flexiclaudent spiral operculum as the ancestral form. This leads us to propose the “periostracum shaving” model in prosobranchs to account for the origin of this kind of operculum. According to this model, in the earliest trochospiral gastropods the periostracum ceased to serve a shell-formation function at the band of overlap between whorls (the parietal band). The periostracal band was then extruded from the shell to constitute an incipient operculum, taking on the appearance of a spiral strip coiling opposite to the shell. The parietal segment of the periostracal groove migrated toward the epipodium and became independent from the rest of the mantle. The concomitant development of an opercular disc allowed the successive turns of periostracal strip to seal together. In this way, a spiral operculum emerged, coiling counterclockwise without matching the aperture shape. During the course of prosobranch evolution, rigiclaudent spiral opercula emerged several times from the ancestral flexiclaudent type, although they were always restricted to apertures with a spiral-shaped outer (labral) edge. Such opercula enlarged the range of shell morphologies for which the operculum constituted an efficient protective barrier to include those of neritoidean or naticoidean type. The onset of calcification in opercula took place with the rigiclaudent type. Concentric opercula also evolved independently from rigiclaudent spiral opercula in several gastropod groups, thus further broadening the spectrum of apertures and, hence, of shell morphologies using opercula for protection. From the standpoint of adaptation, the concentric type was probably the only one available to neogastropods having long and wide siphonal canals.