Intraductal papillary neoplasms of the bile ducts: a comparative study of a rare disease in Europe and Nagoya, Japan.

BACKGROUND: Intraductal papillary neoplasm of the bile ducts (IPNB) is a rare disease in Western countries. The aim of this study was to compare tumor characteristics, management strategies, and outcomes between Western and Eastern patients who underwent surgical resection for IPNB. METHODS: A multi-institutional retrospective series of patients with IPNB undergoing surgery between January 2010 and December 2020 was gathered under the auspices of the European-African Hepato-Pancreato-Biliary Association (E-AHPBA), and at Nagoya University Hospital, Japan. RESULTS: A total of 85 patients (51% male; median age 66 years) from 28 E-AHPBA centers were compared to 91 patients (64% male; median age 71 years) from Nagoya. Patients in Europe had more multiple lesions (23% vs 2%, P < .001), less invasive carcinoma (42% vs 85%, P < .001), and more intrahepatic tumors (52% vs 24%, P < .001) than in Nagoya. Patients in Europe experienced less 90-day grade >3 Clavien-Dindo complications (33% vs 68%, P < .001), but higher 90-day mortality rate (7.0% vs 0%, P = .03). R0 resections (81% vs 82%) were similar. Overall survival, excluding 90-day postoperative deaths, was similar in both regions. DISCUSSION: Despite performing more extensive resections, the low perioperative mortality rate observed in Nagoya was probably influenced by a combination of patient-, tumor-, and surgery-related factors.

Recent Bendamustine Treatment Before Apheresis Has a Negative Impact on Outcomes in Patients With Large B-Cell Lymphoma Receiving Chimeric Antigen Receptor T-Cell Therapy.

PURPOSE: Approximately 30%-40% of patients with relapsed/refractory (R/R) large B-cell lymphoma (LBCL) infused with CD19-targeted chimeric antigen receptor (CAR) T cells achieve durable responses. Consensus guidelines suggest avoiding bendamustine before apheresis, but specific data in this setting are lacking. We report distinct outcomes after CAR T-cell therapy according to previous bendamustine exposure. METHODS: The study included CAR T-cell recipients from seven European sites. Safety, efficacy, and CAR T-cell expansion kinetics were analyzed according to preapheresis bendamustine exposure. Additional studies on the impact of the washout period and bendamustine dose were performed. Inverse probability treatment weighting (IPTW) and propensity score matching (PSM) analyses were carried out for all efficacy comparisons between bendamustine-exposed and bendamustine-naïve patients. RESULTS: The study included 439 patients with R/R LBCL infused with CD19-targeted commercial CAR T cells, of whom 80 had received bendamustine before apheresis. Exposed patients had significantly lower CD3+ cells and platelets at apheresis. These patients had a lower overall response rate (ORR, 53% v 72%; P < .01), a shorter progression-free survival (PFS, 3.1 v 6.2 months; P = .04), and overall survival (OS, 10.3 v 23.5 months; P = .01) in comparison with the bendamustine-naïve group. Following adjustment methods for baseline variables, these differences were mitigated. Focusing on the impact of bendamustine washout before apheresis, those with recent (<9 months) exposure (N = 42) displayed a lower ORR (40% v 72%; P < .01), shorter PFS (1.3 v 6.2 months; P < .01), and OS (4.6 v 23.5 months; P < .01) in comparison with bendamustine-naïve patients. These differences remained significant after IPTW and PSM analysis. Conversely, the cumulative dose of bendamustine before apheresis did not affect CAR-T efficacy outcomes. CONCLUSION: Recent bendamustine exposure before apheresis was associated with negative treatment outcomes after CD19-targeted CAR T-cell therapy and should be therefore avoided in CAR T-cell candidates.

Lupus anticoagulant-hypoprothrombinemia syndrome: A cerebral bleeding case report as systemic lupus erythematosus debut.

Lupus anticoagulant-hypoprothrombinaemia syndrome (LAHPS) is a rare disorder caused by the presence of lupus anticoagulant (LA) and acquired prothrombin deficiency, which may present with severe haemorrhagic manifestations. LAHPS is usually associated with systemic lupus erythematosus (SLE), or infections and it is more frequent in the paediatric population and female gender. We describe a 42-year-old man with thrombotic antiphospholipid syndrome (APS) on chronic anticoagulation treatment with acenocoumarol who presented with spontaneous intracranial bleeding, prolongation of prothrombin time (PT), activated partial thromboplastin time (APTT) and low factor II levels (after optimal anticoagulation reversal) as a debut of SLE.

Lupus anticoagulant-hypoprothrombinemia syndrome: A cerebral bleeding case report as systemic lupus erythematosus debut / Síndrome anticoagulante lúpico-hipoprotrombinemia: caso clínico de hemorragia cerebral como inicio de lupus eritematoso sistémico

Lupus anticoagulant-hypoprothrombinaemia syndrome (LAHPS) is a rare disorder caused by the presence of lupus anticoagulant (LA) and acquired prothrombin deficiency, which may present with severe haemorrhagic manifestations. LAHPS is usually associated with systemic lupus erythematosus (SLE), or infections and it is more frequent in the paediatric population and female gender. We describe a 42-year-old man with thrombotic antiphospholipid syndrome (APS) on chronic anticoagulation treatment with acenocoumarol who presented with spontaneous intracranial bleeding, prolongation of prothrombin time (PT), activated partial thromboplastin time (APTT) and low factor II levels (after optimal anticoagulation reversal) as a debut of SLE.(AU)

El síndrome de anticoagulante lúpico-hipoprotrombinemia (LAHPS, por sus siglas en inglés) es un trastorno raro, causado por la presencia de anticoagulante lúpico (AL) y deficiencia adquirida de protrombina, que puede cursar con manifestaciones hemorrágicas graves. El LAHPS suele asociarse a lupus eritematoso sistémico (LES) o infecciones, y es más frecuente en población pediátrica y en el género femenino. Describimos a un varón de 42 años con síndrome antifosfolípido (SAF) trombótico en tratamiento anticoagulante crónico con acenocumarol que presentó sangrado intracraneal espontáneo, prolongación tanto del tiempo de protrombina (TP) como del tiempo de tromboplastina parcial activada (TTPA) y factor bajo de nivel II (después de la reversión óptima de la anticoagulación) como inicio de LES.(AU)

Intraductal papillary neoplasms of the bile duct: a European retrospective multicenter observational study (EUR-IPNB study).

BACKGROUND/PURPOSE: Intraductal papillary neoplasm of the bile duct (IPNB) is a rare disease in Western countries. The main aim of this study was to characterize current surgical strategies and outcomes in the mainly European participating centers. METHODS: A multi-institutional retrospective series of patients with a diagnosis of IPNB undergoing surgery between 1 January 2010 and 31 December 2020 was gathered under the auspices of the European-African Hepato-Pancreato-Biliary Association. The textbook outcome (TO) was defined as a non-prolonged length of hospital stay plus the absence of any Clavien-Dindo grade at least III complications, readmission, or mortality within 90 postoperative days. RESULTS: A total of 28 centers contributed 85 patients who underwent surgery for IPNB. The median age was 66 years (55-72), 49.4% were women, and 87.1% were Caucasian. Open surgery was performed in 72 patients (84.7%) and laparoscopic in 13 (15.3%). TO was achieved in 54.1% of patients, reaching 63.8% after liver resection and 32.0% after pancreas resection. Median overall survival was 5.72 years, with 5-year overall survival of 63% (95% CI: 50-82). Overall survival was better in patients with Charlson comorbidity score 4 or less versus more than 4 ( P =0.016), intrahepatic versus extrahepatic tumor ( P =0.027), single versus multiple tumors ( P =0.007), those who underwent hepatic versus pancreatic resection ( P =0.017), or achieved versus failed TO ( P =0.029). Multivariable Cox regression analysis showed that not achieving TO (HR: 4.20; 95% CI: 1.11-15.94; P =0.03) was an independent prognostic factor of poor overall survival. CONCLUSIONS: Patients undergoing liver resection for IPNB were more likely to achieve a TO outcome than those requiring a pancreatic resection. Comorbidity, tumor location, and tumor multiplicity influenced overall survival. TO was an independent prognostic factor of overall survival.

Enhanced thrombin generation detected with ST-Genesia analyzer in patients with newly diagnosed multiple myeloma.

The issue of how to identify newly diagnosed multiple myeloma (NDMM) patients requiring thromboprophylaxis remains unsolved. Several changes in thrombin generation (TG)-derived parameters have been described in multiple myeloma (MM) patients recently. Assessment of prothrombotic risk with a fully automated TG analyzer could reduce interlaboratory variability. Our objective was to determine whether ST-Genesia® could reveal a hypercoagulable state in NDMM compared to healthy controls. We conducted a multicenter observational study of NDMM requiring initial treatment to compare TG parameters obtained with ST-Genesia® analyzer and ST-ThromboScreen® reagent with a control group. Clinical data were obtained from medical records and blood samples were collected before initial anti-myeloma therapy. A thrombophilia panel was performed in all patients. Compared to age- and sex-matched controls (n = 83), NDMM patients (n = 83) had significantly higher peak height, higher velocity index, shorter time-to-peak and lower percentage of endogenous thrombin potential (ETP) inhibition after adding thrombomodulin (TM) (ETP%inh). NDMM on prophylactic low molecular weight heparin (LMWH) showed reduced both peak height and velocity index compared to NDMM who had not yet started VTE prophylaxis, similar to that of controls. Moreover, partial correction of ETP%inh was observed in MM patients on LMWH. The presence of a thrombophilia did not modify the TG phenotype. Untreated NDMM patients showed an enhanced TG, regardless of their thrombophilia status. They generate a higher peak of thrombin, take less time to produce it, and exhibit resistance to TM inhibition. Our findings suggest that standard prophylactic dose of LMWH may reduce TG at levels of healthy controls.

Prognostic Significance of Lung and Cava Vein Ultrasound in Elderly Patients Admitted for Acute Heart Failure: PROFUND-IC Registry Analysis.

Introduction: Heart failure is an extremely prevalent disease in the elderly population of the world. Most patients present signs and symptoms of decompensation of the disease due to worsening congestion. This congestion has been clinically assessed through clinical signs and symptoms and complementary imaging tests, such as chest radiography. Recently, pulmonary and inferior vena cava ultrasound has been shown to be useful in assessing congestion but its prognostic significance in elderly patients has been less well evaluated. Objectives: This study aims to compare the clinical and radiological characteristics and predictive values for mortality in patients admitted for heart failure through the determination of B lines by lung ultrasound and the degree of collapsibility of the inferior vena cava (IVC). Secondarily, the study aims to assess the prediction of 30-day mortality based on the diameter of the IVC by means of the ROC curve. Methods: This is an observational cohort study based on data collected in the PROFUND-IC study, a nationwide multicentric registry of patients admitted with decompensated heart failure. Data were collected from these patients between October 2020 and April 2022. Results: A total of 482 patients were entered into the PROFUND-IC registry between October 2020 and April 2022. Bedside clinical ultrasound was performed during admission in 301 patients (64.3%). The number of patients with more than 6 B-lines on lung ultrasound amounted to 194 (66%). Statistically significant differences in 30-day mortality (22.1% vs. 9.2%; p = 0.01) were found in these patients. The sum of patients with IVC collapsibility of less than 50% amounted to 195 (67%). Regarding prognostic value, collapsibility data were significant for the number of admissions in the last year (12.5% vs. 5.5%; p = 0.04), in-hospital mortality (10.1% vs. 3.3%, p = 0.04) and 30-day mortality (22.6% vs. 8.1%; p < 0.01), but not for readmissions. Regarding the prognostic value of IVC diameter for 30-day mortality, the area under the ROC curve (AUC) was 0.73, with a p < 0.01. The curve cut-off point with the highest sensitivity (70%) and specificity (70.3%) was for an IVC value of 22.5 mm. In the logistic regression analysis, we observed that the variable most associated with patient survival at 30 days was the presence of a collapsible inferior vena cava, with more than 50% OR 0.359 (CI 0.139−0.926; p = 0.034). Conclusions: The subgroups of patients analyzed with more than six B lines per field and IVC collapsibility less than or equal to 50%, as measured by clinical ultrasound, had higher 30-day mortality rates than patients who did not fall into these subgroups. IVC diameter may be a good independent predictor of 30-day mortality in patients with decompensated heart failure. Comparing both ultrasound variables, it seems that in our population, the assessment of the inferior vena cava may be more associated with short-term prognosis than the pulmonary congestion variables assessed by B lines.

Flow Cytometry and Molecular Techniques Could Complement Morphological Detection of Leukemic Infiltration in Ascitic Fluids: A Case Report.

Extramedullary involvement of acute myeloid leukemia (AML) is infrequent, and ascitic infiltration is even more unusual. We present a case of a 48-year-old woman diagnosed with NPM1-mutated AML that debuted with ascites, for which morphological studies of the ascitic fluid did not detect leukemic infiltration, maybe due to technical problems in the sample preparation. Multiparameter flow cytometry (MFC) detected a blast population compatible with AML, and allele-specific PCR detected NPM1-mutated transcripts. Body fluid infiltrations are an infrequent initial manifestation or sign of progression in AML. As far as we know, this is the first reported case of an NPM1-mutated AML that debuted with ascites, and also the first description of the utilization of molecular techniques to detect the leukemic origin of the ascites. This case highlights that, given that allele-specific PCR and MFC increase the sensitivity of morphological studies, these techniques should be routinely applied in the study of any kind of effusion detected in an AML patient.

Strategy to prevent epitope masking in CAR.CD19+ B-cell leukemia blasts.

Chimeric antigen receptor T-cells (CAR T-cells) for the treatment of relapsing/refractory B-cell precursor acute lymphoblastic leukemia have led to exciting clinical results. However, CAR T-cell approaches revealed a potential risk of CD19-/CAR+ leukemic relapse due to inadvertent transduction of leukemia cells. BACKGROUND: METHODS: We evaluated the impact of a high percentage of leukemia blast contamination in patient-derived starting material (SM) on CAR T-cell drug product (DP) manufacturing. In vitro as well as in vivo models were employed to identify characteristics of the construct associated with better profile of safety in case of inadvertent B-cell leukemia transduction during CAR T-cell manufacturing. RESULTS: The presence of large amounts of CD19+ cells in SM did not affect the transduction level of DPs, as well as the CAR T-cell rate of expansion at the end of standard production of 14 days. DPs were deeply characterized by flow cytometry and molecular biology for Ig-rearrangements, showing that the level of B-cell contamination in DPs did not correlate with the percentage of CD19+ cells in SM, in the studied patient cohort. Moreover, we investigated whether CAR design may affect the control of CAR+ leukemia cells. We provided evidences that CAR.CD19 short linker (SL) prevents complete epitope masking in CD19+CAR+ leukemia cells and we demonstrated in vitro and in vivo that CD19 +CAR(SL)+leukemic cells are killed by CAR.CD19 T-cells. CONCLUSIONS: Taken together, these data suggest that a VL-VH SL may result in a safe CAR-T product, even when manufacturing starts from biological materials characterized by heavy contamination of leukemia blasts.

Incidence and clinical profile of venous thromboembolism in hospitalized COVID-19 patients from Madrid region.

BACKGROUND: COVID-19 related in-hospital venous thromboembolism (VTE) incidence is high but data reported vary significantly. Some studies show that up to half of the events are diagnosed early after admission. OBJECTIVES: To study symptomatic VTE incidence in acute COVID-19 hospitalized patients and to describe timing of VTE diagnosis. METHODS: Multicenter cohort of 5966 patients hospitalized with acute COVID-19. Multicenter Registry of 844 hospitalized patients with acute COVID-19 and associated acute VTE. RESULTS: By the time of cohort data collection, 68 patients (1.14%) were still hospitalized, 19.8% had died, and 5.4% required ICU. During a median follow-up of 6 days (IQR, 4-12), 183 patients (3.07%; 95% CI, 2.64-3.55) presented a symptomatic VTE event. The cumulative incidences of VTE at 7, 14 and 21 days in wards [2.3% (95% CI, 1.9-2.7), 3.6% (95% CI, 3.0-4.3), and 4.3% (95% CI, 3.5-5.1)] were similar to the ones reported in ICU [2.2% (95% CI, 1.0-4.4), 2.9% (95% CI, 1.5-5.3), and 4.1% (95% CI, 2.2-6.8)], but at 30 and 60 days were higher in ICU [6.9% (95% CI, 4.2-10.5), and 12.8% (95% CI, 8.1-18.5)] than in wards. Eighty-eight VTE events (48%) were diagnosed early, within 48 h of admission. VTE was not associated with death (HR, 0.79; 95% CI, 0.55-1.12). CONCLUSIONS: Incidence of symptomatic VTE in our COVID-19 cohort is consistent with that of other real-life studies recently published. Early VTE events are, along with COVID-19, the reason for admission rather than an in-hospital complication.

Development and validation of a predictive model of in-hospital mortality in COVID-19 patients.

We retrospectively evaluated 2879 hospitalized COVID-19 patients from four hospitals to evaluate the ability of demographic data, medical history, and on-admission laboratory parameters to predict in-hospital mortality. Association of previously published risk factors (age, gender, arterial hypertension, diabetes mellitus, smoking habit, obesity, renal failure, cardiovascular/ pulmonary diseases, serum ferritin, lymphocyte count, APTT, PT, fibrinogen, D-dimer, and platelet count) with death was tested by a multivariate logistic regression, and a predictive model was created, with further validation in an independent sample. A total of 2070 hospitalized COVID-19 patients were finally included in the multivariable analysis. Age 61-70 years (p<0.001; OR: 7.69; 95%CI: 2.93 to 20.14), age 71-80 years (p<0.001; OR: 14.99; 95%CI: 5.88 to 38.22), age >80 years (p<0.001; OR: 36.78; 95%CI: 14.42 to 93.85), male gender (p<0.001; OR: 1.84; 95%CI: 1.31 to 2.58), D-dimer levels >2 ULN (p = 0.003; OR: 1.79; 95%CI: 1.22 to 2.62), and prolonged PT (p<0.001; OR: 2.18; 95%CI: 1.49 to 3.18) were independently associated with increased in-hospital mortality. A predictive model performed with these parameters showed an AUC of 0.81 in the development cohort (n = 1270) [sensitivity of 95.83%, specificity of 41.46%, negative predictive value of 98.01%, and positive predictive value of 24.85%]. These results were then validated in an independent data sample (n = 800). Our predictive model of in-hospital mortality of COVID-19 patients has been developed, calibrated and validated. The model (MRS-COVID) included age, male gender, and on-admission coagulopathy markers as positively correlated factors with fatal outcome.

Tuberculosis situation in the program area of a general acute care hospital in Buenos Aires City, 2017-2019 / Tuberculosis situation in the program area of a general acute care hospital in Buenos Aires City, 2017-2019

INTRODUCCIÓN: La tuberculosis (TB) genera una gran carga de enfermedad a nivel global. Su elevada presencia en grandes ciudades se explica porque ellas son escenarios de urbanización acelerada, fuertes inequidades sociales y concentración de circunstancias de vulnerabilidad. El objetivo fue analizar la situación epidemiológica de la TB en un área programática (AP) de la Ciudad de Buenos Aires entre 2017 y 2019. MÉTODOS: Se realizó un estudio descriptivo de corte transversal. La población de estudio fueron los casos notificados de TB en residentes en el AP del Hospital Fernández (HF). La fuente de datos principal fue el Sistema Nacional de Vigilancia de Salud. RESULTADOS: Se registraron 375 casos. En 2017 se presentó la tasa de notificación de TB más alta del AP (29,2). Los casos se concentraron en el barrio de Retiro y alcanzaron su mayor tasa en 2018 (134,5). Los barrios populares presentaron 12 veces la tasa del AP (305,1). De todos los casos, 213 fueron de género masculino (56,8%), con 29 años como mediana de edad. Mayormente fueron notificados por la red de efectores del AP del HF. Respecto a la evolución, en 169 casos fue satisfactoria (45,1%), y 138 no registraron datos de evolución (36,8%). DISCUSIÓN: El análisis epidemiológico desagregado reveló la gran complejidad del territorio respecto a este padecimiento de salud. Las redes de abordaje interdisciplinarias e intersectoriales resultan claves para garantizar la accesibilidad al cuidado y tratamiento en esta población.

Thrombin generation in subjects with lupus anticoagulant without prior thrombosis or gestational morbidities.

BACKGROUND: Lupus anticoagulant (LA) can be a cause of thrombosis and/or pregnancy morbidities, producing antiphospholipid syndrome (APS). An increase in thrombin generation (TG) is correlated with prothrombotic status. Several changes in TG-derived parameters have been reported in APS patients. OBJECTIVES: Evaluate whether the TG phenotype of APS can also be described in LA subjects without clinical manifestations of APS, and to investigate the possible influence of both LA potency and antiphospholipid (aPL) profile on it. RESULTS: TG was analyzed in 153 cases of LA and 41 healthy controls. We have observed prolongation of both lag time (3.7 min vs 2.32 min, p < 0.001) and time to peak (6.48 min vs 5.27 min, p < 0.001), increased peak height (221.7 nM vs 182.7 nM, p < 0.001), slightly higher ETP (221.7 nM·min vs 182.7 nM·min, p = 0.041), and higher velocity index (100.7 nM/min vs 74.53 nM/min, p = 0.001) in LA subjects compared to controls. After adding thrombomodulin (TM), ETP%inh was significantly lower in LA group (37.90% vs 59.90%, p < 0.001) showing resistance to TM/activated protein C (APC). Significant differences were found in lag time, time to peak and ETP%inh according to the potency and aPL profile. CONCLUSIONS: Previously described differences in TG-derived parameters in APS patients have been confirmed in incidental LA subjects: prolonged lag time and time to peak, slightly higher ETP, higher peak height, and less sensitivity to TM/APC. High LA potency and triple-positive aPL profile enhance differences in lag time, time to peak and, especially, increase APC resistance, but no effect in ETP was observed.

C3G contributes to platelet activation and aggregation by regulating major signaling pathways.

C3G is a GEF (guanine nucleotide exchange factor) for Rap GTPases, among which the isoform Rap1b is an essential protein in platelet biology. Using transgenic mouse models with platelet-specific overexpression of C3G or mutant C3GΔCat, we have unveiled a new function of C3G in regulating the hemostatic function of platelets through its participation in the thrombin-PKC-Rap1b pathway. C3G also plays important roles in angiogenesis, tumor growth, and metastasis through its regulation of the platelet secretome. In addition, C3G contributes to megakaryopoiesis and thrombopoiesis. Here, we used a platelet-specific C3G-KO mouse model to further support the role of C3G in hemostasis. C3G-KO platelets showed a significant delay in platelet activation and aggregation as a consequence of the defective activation of Rap1, which resulted in decreased thrombus formation in vivo. Additionally, we explored the contribution of C3G-Rap1b to platelet signaling pathways triggered by thrombin, PMA or ADP, in the referenced transgenic mouse model, through the use of a battery of specific inhibitors. We found that platelet C3G is phosphorylated at Tyr504 by a mechanism involving PKC-Src. This phosphorylation was shown to be positively regulated by ERKs through their inhibition of the tyrosine phosphatase Shp2. Moreover, C3G participates in the ADP-P2Y12-PI3K-Rap1b pathway and is a mediator of thrombin-TXA2 activities. However, it inhibits the synthesis of TXA2 through cPLA2 regulation. Taken together, our data reveal the critical role of C3G in the main pathways leading to platelet activation and aggregation through the regulation of Rap1b.

C3G, through its GEF activity, induces megakaryocytic differentiation and proplatelet formation.

BACKGROUND: Megakaryopoiesis allows platelet formation, which is necessary for coagulation, also playing an important role in different pathologies. However, this process remains to be fully characterized. C3G, an activator of Rap1 GTPases, is involved in platelet activation and regulates several differentiation processes. METHODS: We evaluated C3G function in megakaryopoiesis using transgenic mouse models where C3G and C3GΔCat (mutant lacking the GEF domain) transgenes are expressed exclusively in megakaryocytes and platelets. In addition, we used different clones of K562, HEL and DAMI cell lines with overexpression or silencing of C3G or GATA-1. RESULTS: We found that C3G participates in the differentiation of immature hematopoietic cells to megakaryocytes. Accordingly, bone marrow cells from transgenic C3G, but not those from transgenic C3GΔCat mice, showed increased expression of the differentiation markers CD41 and CD61, upon thrombopoietin treatment. Furthermore, C3G overexpression increased the number of CD41+ megakaryocytes with high DNA content. These results are supported by data obtained in the different models of megakaryocytic cell lines. In addition, it was uncovered GATA-1 as a positive regulator of C3G expression. Moreover, C3G transgenic megakaryocytes from fresh bone marrow explants showed increased migration from the osteoblastic to the vascular niche and an enhanced ability to form proplatelets. Although the transgenic expression of C3G in platelets did not alter basal platelet counts, it did increase slightly those induced by TPO injection in vivo. Moreover, platelet C3G induced adipogenesis in the bone marrow under pathological conditions. CONCLUSIONS: All these data indicate that C3G plays a significant role in different steps of megakaryopoiesis, acting through a mechanism dependent on its GEF activity.

C3G promotes a selective release of angiogenic factors from activated mouse platelets to regulate angiogenesis and tumor metastasis.

Previous observations indicated that C3G (RAPGEF1) promotes α-granule release, evidenced by the increase in P-selectin exposure on the platelet surface following its activation. The goal of the present study is to further characterize the potential function of C3G as a modulator of the platelet releasate and its implication in the regulation of angiogenesis. Proteomic analysis revealed a decreased secretion of anti-angiogenic factors from activated transgenic C3G and C3G∆Cat platelets. Accordingly, the secretome from both transgenic platelets had an overall pro-angiogenic effect as evidenced by an in vitro capillary-tube formation assay with HUVECs (human umbilical vein endothelial cells) and by two in vivo models of heterotopic tumor growth. In addition, transgenic C3G expression in platelets greatly increased mouse melanoma cells metastasis. Moreover, immunofluorescence microscopy showed that the pro-angiogenic factors VEGF and bFGF were partially retained into α-granules in thrombin- and ADP-activated mouse platelets from both, C3G and C3GΔCat transgenic mice. The observed interaction between C3G and Vesicle-associated membrane protein (Vamp)-7 could explain these results. Concomitantly, increased platelet spreading in both transgenic platelets upon thrombin activation supports this novel function of C3G in α-granule exocytosis. Collectively, our data point out to the co-existence of Rap1GEF-dependent and independent mechanisms mediating C3G effects on platelet secretion, which regulates pathological angiogenesis in tumors and other contexts. The results herein support an important role for platelet C3G in angiogenesis and metastasis.

Duodenal involvement by seminomatous tumors.

Testicular germ cell tumors, though rare (1%), represent the most common neoplasm among young men. Gastrointestinal involvement from these malignancies usually presents as bowel obstruction and digestive bleeding, but their frequency is low (5%). The patterns of this involvement are: infiltration from affected retroperitoneal lymph nodes or, less frequently, by peritoneal seeding and direct hematogenous spread. Particularly, infiltration of duodenum is also rare, though its real frequency is not well defined. Moreover, the affinity for GI tract differs among the histological types of GCT, being seminomatous tumors an exceedingly unfrequent cause of duodenal infiltration. We herein present a recent case in our institution of severe anemia due to gastrointestinal bleeding in the context of giant retroperitoneal bulky metastatic mass infiltrating duodenum as first manifestation of a testicular pure seminoma.

Septic shock secondary to colonic fistula as clinical debut of liver hydatid cyst

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