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The Spanish Society of Medical Oncology (SEOM) last published clinical guidelines on venous thromboembolism (VTE) and cancer in 2019, with a partial update in 2020. In this new update to the guidelines, SEOM seeks to incorporate recent evidence, based on a critical review of the literature, to provide practical current recommendations for the prophylactic and therapeutic management of VTE in patients with cancer. Special clinical situations whose management and/or choice of currently recommended therapeutic options (low-molecular-weight heparins [LMWHs] or direct-acting oral anticoagulants [DOACs]) is controversial are included.

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BACKGROUND: Our objective was to conduct a systematic review of the effects of hydrolyzed collagen supplementation on the proliferation and activation of fibroblasts. METHODS: The search was conducted for journals that published articles in the English language, peer-reviewed, meeting the following criteria: (a) randomized clinical trials, (b) randomized studies in animals or humans, (c) in vitro studies, (d) studies using hydrolyzed collagens or collagen peptides, and (e) studies assessing alterations on fibroblasts as the primary or secondary outcome. We utilized the main journal databases PubMed/Web of Science and ongoing reviews by PROSPERO. For bias risk and methodological quality, we used an adaptation of the Downs and Black checklist. Our review followed the PRISMA checklist, conducted from February 2024 to the first week of March 2024, by two independent researchers (P.A.Q.I. and R.P.V.). RESULTS: Eleven studies were included in this review, where our findings reinforce the notion that hydrolyzed collagens or collagen peptides at concentrations of 50-500 µg/mL are sufficient to stimulate fibroblasts in human and animal tissues without inducing toxicity. Different enzymatic processes may confer distinct biological properties to collagens, allowing for scenarios favoring fibroblast promotion or antioxidant effects. Lastly, collagens with lower molecular weights exhibit greater bioavailability to adjacent tissues. CONCLUSIONS: Hydrolyzed collagens or collagen peptides with molecular sizes ranging from <3 to 3000 KDa promote the stimulation of fibroblasts in human tissues.

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Bacterial cellulose (BC) is an emerging material for high-end applications due to its biocompatibility and physicochemical characteristics. However, the scale-up production of this material is still expensive, with the culture medium constituting one-third of the total cost. Herein, four different media (yeast nitrogen base, YNB; Murashige and Skoog, MSO; black tea; and NPK fertilizer solution) were compared while using sucrose as an additional carbon source. The yields of BC were best for YNB and fertilizer with 0.37 and 0.34 gBC/gC respectively. These two were then compared using glucose as a carbon source, with improvements in the production of 29% for the fertilizer, while only an 8% increase for YNB was seen; however, as the carbon concentration increased with a fixed N concentration, the yield was lower but the rate of production of BC increased. The obtained BC films were sanitized and showed low molecular weight and all the expected cellulose characteristic FT-IR bands while SEM showed nanofibers around 0.1 µm. Compared to traditional methods for lab-scale production, the use of the fertilizer and the consortium represent benefits compared to traditional lab-scale BC culture methods such as a competitive cost (two times lower) while posing resilience and tolerance to stress conditions given that it is produced by microbial communities and not with a single strain. Additionally, the low molecular weight of the films could be of interest for certain coating formulations.

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Biological macromolecules are found in different shapes and sizes. Among these, enzymes catalyze biochemical reactions and are essential in all organisms, but is there a limit size for them to function properly? Large enzymes such as catalases have hundreds of kDa and are formed by multiple subunits, whereas most enzymes are smaller, with molecular weights of 20-60 kDa. Enzymes smaller than 10 kDa could be called microenzymes and the present literature review brings together evidence of their occurrence in nature. Additionally, bioactive peptides could be a natural source for novel microenzymes hidden in larger peptides and molecular downsizing could be useful to engineer artificial enzymes with low molecular weight improving their stability and heterologous expression. An integrative approach is crucial to discover and determine the amino acid sequences of novel microenzymes, together with their genomic identification and their biochemical biological and evolutionary functions.

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Xylanase is widely used in various industries such as food processing, paper, textiles, and leather tanning. In this study, Bacillus cereus L-1 strain was isolated and identified as capable of producing low molecular weight xylanase through 16 s rRNA sequencing. Maximum xylanase yield of 15.51 ± 2.08 U/mL was achieved under optimal fermentation conditions (5% inoculum, 20 g/L xylan, pH 6.0, for 24 h). After purification via ammonium sulfate precipitation and High-S ion exchange chromatography, electrophoretic purity xylanase was obtained with a 28-fold purification and specific activity of 244.97 U/mg. Xylanase had an optimal pH of 6.5 and temperature of 60 °C and displayed thermostability at 30 °C and 40 °C with 48.56% and 45.97% remaining activity after 180 min, respectively. The xylanase retained more than 82.97% of its activity after incubation for 24 h at pH 5.0 and was sensitive to metal ions, especially Mg2+ and Li+. Purified xylanase showed a molecular weight of 23 kDa on SDS-PAGE, and partial peptide sequencing revealed homology to the endo-1,4-beta-xylanase with a molecular weight of 23.3 kDa through LC/MS-MS (liquid chromatography-tandem mass spectrometry). This study suggests that the purified xylanase is easier to purify and enriches low molecular weight xylanases from bacteria source.

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Aquatic macrophytes contain high levels of hydrosoluble compounds. These compounds disproportionately support microbial breakdown and affect biological oxygen demand in eutrophic waters. In this study, we investigated the fate of leachates from free-floating macrophytes (Pistia stratiotes and Eichhornia crassipes) usually present in eutrophic tropical lacustrine environments. After extraction, the leachates were fractioned into high and low molecular weight compounds and incubated under aerobic conditions, in the dark and at 20.0 ± 1.3 °C. The concentrations of dissolved oxygen and the total, dissolved, and particulate organic carbon (TOC, DOC, and POC) were determined during 60 days. The selected leachates supported the detritus trophic chain of the Barra Bonita Reservoir. High rates of carbon transfer were measured, which were ascribed to the temperature selected (20 °C), nutrient availability, and labile fractions of the leachates. Decomposition occurred mainly through catabolic pathways (mineralization), with the formation of POC (immobilization) being only minor. In the early stages of P. stratiotes and E. crassipes decomposition, the mineralization of leachates (mainly the low molecular weight) led to declines in dissolved oxygen. Owing to the low rates of mass loss, the recalcitrant fractions of these leachates should constitute the main forms of organic carbon exported from the reservoir.

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Respiratory sensitization encompasses a group of diseases that manifest through airway hyperresponsiveness and airflow limitation. Although the concerns regarding human health, to date there are still no validated methods for preclinical assessment of this class of toxicants once the chemical respiratory allergy mechanistic framework is not fully understood. As Dendritic Cells (DCs) are the bridging elements between innate and adaptative immune responses, we preliminarily investigated the biological alterations triggered by seven different LMW respiratory allergens in the DC model THP-1. The results have shown that exposure to respiratory allergens promoted alterations in DCs maturation/activation status and triggered pro-inflammatory changes in these cells through increased expression for the CD86/HLA-DR/CD11c surface biomarkers and enhancement in IL-8 and IL-6 production by exposed THP-1 cells. Therefore, evidence was found to support the startpoint for chemical respiratory allergy pathogenesis elucidation, subsidizing the contribution of dendritic cells in such pathomechanisms.

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Snake venom enzymes have a broad range of molecular targets in plasma, tissues, and cells, among which hyaluronan (HA) is outstanding. HA is encountered in the extracellular matrix of diverse tissues and in the bloodstream, and its different chemical configurations dictate the diverse morphophysiological processes in which it participates. Hyaluronidases are highlighted among the enzymes involved in HA metabolism. This enzyme has been detected along the phylogenetic tree, suggesting that hyaluronidases exert multiple biological effects on different organisms. Hyaluronidases have been described in tissues, blood and snake venoms. Snake venom hyaluronidases (SVHYA) contribute to tissue destruction in envenomations and are called spreading factors since their action potentiates venom toxin delivery. Interestingly, SVHYA are clustered in Enzyme Class 3.2.1.35 together with mammalian hyaluronidases (HYAL). Both HYAL and SVHYA of Class 3.2.1.35 act upon HA, generating low molecular weight HA fragments (LMW-HA). LMW-HA generated by HYAL becomes a damage-associated molecular pattern that is recognized by Toll-like receptors 2 and 4, triggering cell signaling cascades culminating in innate and adaptive immune responses that are characterized by lipid mediator generation, interleukin production, chemokine upregulation, dendritic cell activation and T cell proliferation. In this review, aspects of the structures and functions of HA and hyaluronidases in both snake venoms and mammals are presented, and their activities are compared. In addition, the potential immunopathological consequences of HA degradation products generated after snakebite envenoming and their use as adjuvant to enhance venom toxin immunogenicity for antivenom production as well as envenomation prognostic biomarker are also discussed.

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BACKGROUND: Although several studies suggest that heparins prevent arrhythmias caused by acute myocardial infarction (AMI), the molecular mechanisms involved remain unclear. To investigate the involvement of pharmacological modulation of adenosine (ADO) signaling in cardiac cells by a low-molecular weight heparin (enoxaparin; ENOX) used in AMI therapy, the effects of ENOX on the incidences of ventricular arrhythmias (VA), atrioventricular block (AVB), and lethality (LET) induced by cardiac ischemia and reperfusion (CIR) were evaluated, with or without ADO signaling blockers. METHODS: To induce CIR, adult male Wistar rats were anesthetized and subjected to CIR. Electrocardiogram (ECG) analysis was used to evaluate CIR-induced VA, AVB, and LET incidence, after treatment with ENOX. ENOX effects were evaluated in the absence or presence of an ADO A1-receptor antagonist (DPCPX) and/or an inhibitor of ABC transporter-mediated cAMP efflux (probenecid, PROB). RESULTS: VA incidence was similar between ENOX-treated (66%) and control rats (83%), but AVB (from 83% to 33%) and LET (from 75% to 25%) incidences were significantly lower in rats treated with ENOX. These cardioprotective effects were blocked by either PROB or DPCPX. CONCLUSION: These results indicate that ENOX was effective in preventing severe and lethal arrhythmias induced by CIR due to pharmacological modulation of ADO signaling in cardiac cells, suggesting that this cardioprotective strategy could be promising in AMI therapy.

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SUMMARY OBJECTIVE: Our study purposed to examine the complex relationship between low-molecular-weight heparin therapy, multiple pregnancy determinants, and adverse pregnancy outcomes during the third trimester in women with inherited thrombophilia. METHODS: Patients were selected from a prospective cohort of 358 pregnant patients recruited between 2016 and 2018 at the Clinic for Obstetrics and Gynecology, University Clinical Centre of Serbia, Belgrade. RESULTS: Gestational age at delivery (β=-0.081, p=0.014), resistance index of the umbilical artery (β=0.601, p=0.039), and D-dimer (β=0.245, p<0.001) between 36th and 38th weeks of gestation presented the direct predictors for adverse pregnancy outcomes. The model fit was examined using the root mean square error of approximation 0.00 (95%CI 0.00-0.18), the goodness-of-fit index was 0.998, and the adjusted goodness-of-fit index was 0.966. CONCLUSION: There is a need for the introduction of more precise protocols for the assessment of hereditary thrombophilias and the need for the introduction of low-molecular-weight heparin.

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Snake venom enzymes have a broad range of molecular targets in plasma, tissues, and cells, among which hyaluronan (HA) is outstanding. HA is encountered in the extracellular matrix of diverse tissues and in the bloodstream, and its different chemical configurations dictate the diverse morphophysiological processes in which it participates. Hyaluronidases are highlighted among the enzymes involved in HA metabolism. This enzyme has been detected along the phylogenetic tree, suggesting that hyaluronidases exert multiple biological effects on different organisms. Hyaluronidases have been described in tissues, blood and snake venoms. Snake venom hyaluronidases (SVHYA) contribute to tissue destruction in envenomations and are called spreading factors since their action potentiates venom toxin delivery. Interestingly, SVHYA are clustered in Enzyme Class 3.2.1.35 together with mammalian hyaluronidases (HYAL). Both HYAL and SVHYA of Class 3.2.1.35 act upon HA, generating low molecular weight HA fragments (LMW-HA). LMW-HA generated by HYAL becomes a damage-associated molecular pattern that is recognized by Toll-like receptors 2 and 4, triggering cell signaling cascades culminating in innate and adaptive immune responses that are characterized by lipid mediator generation, interleukin production, chemokine upregulation, dendritic cell activation and T cell proliferation. In this review, aspects of the structures and functions of HA and hyaluronidases in both snake venoms and mammals are presented, and their activities are compared. In addition, the potential immunopathological consequences of HA degradation products generated after snakebite envenoming and their use as adjuvant to enhance venom toxin immunogenicity for antivenom production as well as envenomation prognostic biomarker are also discussed.

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Heparin has already been found in a variety of animal tissues but only few of them became effective sources for production of pharmaceutical preparations. Here, we correlate physical-chemical features and anticoagulant activities of structurally similar heparins employed in the past (from bovine lung, HBL), in the present (from porcine intestine, HPI) and in development for future use (from ovine intestine, HOI). Although they indeed have similar composition, our physical-chemical analyses with different chromatography and spectrometric techniques show that both HOI and HBL have molecular size notably lower than HPI and that the proportions of some of their minor saccharide components can vary substantially. Measurements of anticoagulant activities with anti-FIIa and anti-FXa assays confirmed that HPI and HOI have potency similar each other but significantly higher than HBL. Such a lower activity of HBL has been attributed to its reduced molecular size. Considering that HOI also has reduced molecular size, we find that its increased anticoagulant potency might result from an improved affinity to antithrombin (three times higher than HBL) promoted by the high content of N ,3,6-trisulfated glucosamine units, which in turn are directly involved in the heparin-antithrombin binding. Therefore, the anticoagulant activity of different heparins is driven by a balance between different physical-chemical components, especially molecular size and fine-tuning composition. Although such minor but relevant chemical differences reinforce the concept that heparins from different animal sources should indeed be considered as distinct drugs, HOI could be approved for interchangeable use with the gold standard HPI and as a suitable start material for producing new LMWHs.

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Objective The present study describes the preferences and current practices of a sample of knee surgeons in Brazil regarding thromboprophylaxis in total knee arthroplasty (TKA). Method In the present internet survey, surgeons from the Brazilian Knee Surgery Society (SBCJ, in the Portuguese acronym) voluntarily answered an anonymous questionnaire including time of personal surgical experience, perceptions about the best thromboprophylaxis options, and actual practices in their work environment. Results From December 2020 to January 2021, 243 participants answered the questionnaire. All, except for 3 (1.2%), reported using thromboprophylaxis, and most (76%) combined pharmacological and mechanical techniques. The most prescribed drug was enoxaparin (87%), which changed to rivaroxaban (65%) after discharge. The time of thromboprophylaxis initiation varied according to the length of training of the knee surgeon ( p ≤ 0.03), and their preferences and practices differed according to the Brazilian region ( p < 0.05) and the health system in which the surgeons work (public or private sector; p = 0.024). The option for mechanical thromboprophylaxis also depended on the training time of the surgeon. Conclusion Thromboprophylaxis preferences and practices in TKA are diverse across Brazilian regions and health systems (public or private sectors). Given the lack of a national clinical guideline, most orthopedists follow either their hospital guidelines or none. The mechanical prophylaxis method and the little use of aspirin are the points that most diverge from international guidelines and practices.

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Abstract Objective The present study describes the preferences and current practices of a sample of knee surgeons in Brazil regarding thromboprophylaxis in total knee arthroplasty (TKA). Method In the present internet survey, surgeons from the Brazilian Knee Surgery Society (SBCJ, in the Portuguese acronym) voluntarily answered an anonymous questionnaire including time of personal surgical experience, perceptions about the best thromboprophylaxis options, and actual practices in their work environment. Results From December 2020 to January 2021, 243 participants answered the questionnaire. All, except for 3 (1.2%), reported using thromboprophylaxis, and most (76%) combined pharmacological and mechanical techniques. The most prescribed drug was enoxaparin (87%), which changed to rivaroxaban (65%) after discharge. The time of thromboprophylaxis initiation varied according to the length of training of the knee surgeon (p ≤ 0.03), and their preferences and practices differed according to the Brazilian region (p< 0.05) and the health system in which the surgeons work (public or private sector; p= 0.024). The option for mechanical thromboprophylaxis also depended on the training time of the surgeon. Conclusion Thromboprophylaxis preferences and practices in TKA are diverse across Brazilian regions and health systems (public or private sectors). Given the lack of a national clinical guideline, most orthopedists follow either their hospital guidelines or none. The mechanical prophylaxis method and the little use of aspirin are the points that most diverge from international guidelines and practices.

Resumo Objetivo Descrever as preferências e práticas atuais de uma amostra de cirurgiões de joelho do Brasil quanto à forma de tromboprofilaxia na artroplastia total do joelho (ATJ). Método presente pesquisa realizada pela internet, cirurgiões associados à Sociedade Brasileira de Cirurgia do Joelho (SBCJ) foram convidados a responder voluntariamente a um questionário anônimo incluindo o tempo de experiência cirúrgica pessoal, percepções sobre as melhores opções de tromboprofilaxia e as reais práticas no ambiente onde trabalham. Resultados Entre dezembro de 2020 e janeiro de 2021, 243 participantes responderam ao questionário completo. Exceto por 3 (1,2%) participantes, todos declararam praticar tromboprofilaxia, a maioria (76%) combinando as formas farmacológica e mecânica. A droga mais prescrita é a enoxaparina (87%), com modificação para rivaroxabana (65%) após a alta. O momento de início da tromboprofilaxia variou conforme o tempo de formação do cirurgião de joelho (p ≤ 0,03) e as preferências e práticas variaram conforme a região do país (p< 0,05) e o sistema de saúde no qual trabalham os cirurgiões (público ou privado; p= 0,024). A opção por tromboprofilaxia mecânica também dependeu do tempo de formação do cirurgião. Conclusão As preferências e práticas de tromboprofilaxia na ATJ são diversas nas regiões do Brasil e sistemas de saúde (público ou privado). Dada a inexistência de uma diretriz clínica nacional, a maior parte dos ortopedistas segue ou a diretriz de seu próprio hospital ou nenhuma. O método de profilaxia mecânica e a pouca utilização do ácido acetilsalicílico são os pontos que mais destoam das diretrizes e práticas internacionais.

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Heparin is a centennial anticoagulant drug broadly employed for treatment and prophylaxis of thromboembolic conditions. Although unfractionated heparin (UFH) has already been shown to have remarkable pharmacological potential for treating a variety of diseases unrelated with thromboembolism, including cancer, atherosclerosis, inflammation, and virus infections, its high anticoagulant potency makes the doses necessary to exert non-hemostatic effects unsafe due to an elevated bleeding risk. Our group recently developed a new low-anticoagulant bovine heparin (LABH) bearing the same disaccharide building blocks of the UFH gold standard sourced from porcine mucosa (HPI) but with anticoagulant potency approximately 85% lower (approximately 25 and 180 Heparin International Units [IU]/mg). In the present work, we investigated the pharmacokinetics profile, bleeding potential, and anticancer properties of LABH administered subcutaneous into mice. LABH showed pharmacokinetics profile similar to HPI but different from the low-molecular weight heparin (LMWH) enoxaparin and diminished bleeding potential, even at high doses. Subcutaneous treatment with LABH delays the early progression of Lewis lung carcinoma, improves survival, and brings beneficial health outcomes to the mice, without the advent of adverse effects (hemorrhage/mortality) seen in the animals treated with HPI. These results demonstrate that LABH is a promising candidate for prospecting new therapeutic uses for UFH.

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Resumen A pesar de la tromboprofilaxis estándar, el diagnóstico de trombosis es común en pacientes críticos con COVID-19. El objetivo del presente estudio fue evaluar la incidencia de trombosis venosa profunda (TVP) en pacientes con neumonía grave por COVID-19 con requerimientos de asistencia respiratoria mecánica, bajo tromboprofilaxis química con dosis intermedia (1 mg/kg/día) de heparina de bajo peso molecular (enoxaparina). Se trató de un estudio unicéntrico, descriptivo y de corte transversal de datos recopilados en forma prospectiva. Se realizó búsqueda activa y sistemática de TVP en miembros inferiores (o en confluente yúgulosubclavio en su defecto) mediante doppler venoso cada 7 días. Se continuó con la evaluación por doppler semanal hasta la finalización de la ventilación mecánica, el cum plimiento de los 28 días de internación en unidad de cuidados intensivos, el fallecimiento o la suspensión de la tromboprofilaxis con enoxaparina por cualquier causa. Se incluyeron 46 pacientes. Se realizó diagnóstico de TVP en 5 (3 en miembros inferiores y 2 en con fluente yúgulosubclavio). Tres diagnósticos de TVP fueron asociados a la presencia de catéter venoso central (2 en miembros inferiores y 1 en el confluente yúgulosubclavio), dos fallecieron durante el seguimiento por causas vinculadas al síndrome de distrés respiratorio agudo (SDRA) pero no por eventos trombóticos o de sangrado mayor. En todos los casos, los eventos trombóticos fueron asintomáticos. En nuestra serie de pacientes con SDRA moderado/grave secundario a neumonía por COVID-19, la incidencia de TVP fue del 10.9% en aquellos bajo tromboprofilaxis con dosis intermedia (1 mg/kg/día) de enoxaparina.

Abstract Despite standard thrombo prophylaxis, venous thrombosis is common in critically ill patients with COVID-19. The objective of this study was to evaluate deep venous thrombosis (DVT) incidence in patients with severe COVID-19 pneumonia with mechanical ventilation requirements under intermediate dose of chemical thromboprophylaxis (1 mg/kg/day of enoxaparin). This was a single-center, descriptive, cross-sectional study of prospectively collected data. An active and systematic protocol with venous doppler was carried out for DVT diagnosis in lower limbs (or in jugulo-subclavian venous confluence) every 7 days. Weekly doppler evaluation was continued until the end of mechanical ventilation, up to 28 days of intensive care unit admission, until death or until the thromboprophylaxis suspension for any cause. Forty-six patients were included. DVT was diagnosed in 5 (3 in lower limbs and 2 in jugulo-subclavian conflu ent). In 3 cases, DVT was catheter-related (2 in lower limbs and 1 in jugulo-subclavian confluent), 2 died during follow-up due to acute respiratory distress syndrome (ARDS) complications without thrombotic events or major bleeding. All thrombotic events were asymptomatic. In our series of patients with moderate/severe COVID-19 ARDS, DVT incidence was 10.9% under thromboprophylaxis with intermediate dose (1 mg/kg/ day) of enoxaparin.

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Os anticoagulantes e antiagregantes plaquetários são medicamentos utilizados por uma grande parcela da população mundial. Eles são utilizados para prevenir que pacientes de risco desenvolvam doenças cardiovasculares, como o infarto agudo do miocárdio (IAM) ou o acidente vascular cerebral (AVC). Por serem muito utilizados, constantemente o cirurgião-dentista poderá se deparar em sua rotina clínica, com pacientes usuários de anticoagulantes ou antiagregantes. Neste caso, o profissional precisará estar ciente das normas mais atuais de manejo com cada um dos tipos de medicamentos, para que o tratamento seja realizado com sucesso. No presente trabalho, é proposto um Protocolo Operacional Padrão (POP), que pode ser seguido no momento de realizar cirurgias orais em pacientes em uso de Varfarina, Ácido Acetil Salicílico, Heparina de Baixo Peso Molecular, Heparina Não Fracionada, Rivaroxabana e Clopidogrel.

Anticoagulants and antiplatelet agents are drugs used by a large portion of the world population. They are used to prevent at-risk patients from developing cardiovascular diseases, such as acute myocardial infarction (AMI) or stroke (stroke). Because they are widely used, the dental surgeon may constantly encounter patients using anticoagulants or anti-aggregating agents in their clinical routine. In this case, the professional will need to be aware of the most current management standards with each type of medication, so that the treatment is carried out successfully. In the present work, a Standard Operational Protocol (POP) is proposed, which can be followed when performing oral surgeries on patients using Warfarin, Acetyl Salicylic Acid, Low Molecular Weight Heparin, Unfractionated Heparin, Rivaroxaban and Clopidogrel.

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Despite standard thromboprophylaxis, venous thrombosis is common in critically ill patients with COVID-19. The objective of this study was to evaluate deep venous thrombosis (DVT) incidence in patients with severe COVID-19 pneumonia with mechanical ventilation requirements under intermediate dose of chemical thromboprophylaxis (1 mg/kg/day of enoxaparin). This was a single-center, descriptive, cross-sectional study of prospectively collected data. An active and systematic protocol with venous doppler was carried out for DVT diagnosis in lower limbs (or in jugulo-subclavian venous confluence) every 7 days. Weekly doppler evaluation was continued until the end of mechanical ventilation, up to 28 days of intensive care unit admission, until death or until the thromboprophylaxis suspension for any cause. Forty-six patients were included. DVT was diagnosed in 5 (3 in lower limbs and 2 in jugulo-subclavian confluent). In 3 cases, DVT was catheter-related (2 in lower limbs and 1 in jugulo-subclavian confluent), 2 died during follow-up due to acute respiratory distress syndrome (ARDS) complications without thrombotic events or major bleeding. All thrombotic events were asymptomatic. In our series of patients with moderate/severe COVID-19 ARDS, DVT incidence was 10.9% under thromboprophylaxis with intermediate dose (1 mg/kg/ day) of enoxaparin.

A pesar de la tromboprofilaxis estándar, el diagnóstico de tromb osis es común en pacientes críticos con COVID-19. El objetivo del presente estudio fue evaluar la incidencia de trombosis venosa profunda (TVP) en pacientes con neumonía grave por COVID-19 con requerimientos de asistencia respiratoria mecánica, bajo tromboprofilaxis química con dosis intermedia (1 mg/kg/día) de heparina de bajo peso molecular (enoxaparina). Se trató de un estudio unicéntrico, descriptivo y de corte transversal de datos recopilados en forma prospectiva. Se realizó búsqueda activa y sistemática de TVP en miembros inferiores (o en confluente yúgulosubclavio en su defecto) mediante doppler venoso cada 7 días. Se continuó con la evaluación por doppler semanal hasta la finalización de la ventilación mecánica, el cum plimiento de los 28 días de internación en unidad de cuidados intensivos, el fallecimiento o la suspensión de la tromboprofilaxis con enoxaparina por cualquier causa. Se incluyeron 46 pacientes. Se realizó diagnóstico de TVP en 5 (3 en miembros inferiores y 2 en confluente yúgulosubclavio). Tres diagnósticos de TVP fueron asociados a la presencia de catéter venoso central (2 en miembros inferiores y 1 en el confluente yúgulosubclavio), dos fallecieron durante el seguimiento por causas vinculadas al síndrome de distrés respiratorio agudo (SDRA) pero no por eventos trombóticos o de sangrado mayor. En todos los casos, los eventos trombóticos fueron asintomáticos. En nuestra serie de pacientes con SDRA moderado/grave secundario a neumonía por COVID-19, la incidencia de TVP fue del 10.9% en aquellos bajo tromboprofilaxis con dosis intermedia (1 mg/kg/día) de enoxaparina.

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Pseudomonas aeruginosa is a gram-negative bacterium capable of forming persistent biofilms that are extremely difficult to eradicate. The species is most infamously known due to complications in cystic fibrosis patients. The high mortality of cystic fibrosis is caused by P. aeruginosa biofilms occurring in pathologically overly mucous lungs, which are the major cause facilitating the organ failure. Due to Pseudomonas biofilm-associated infections, remarkably high doses of antibiotics must be administered, eventually contributing to the development of antibiotic resistance. Nowadays, multidrug resistant P. aeruginosa is one of the most terrible threats in medicine, and the search for novel antimicrobial drugs is of the utmost importance. We have studied the effect of low molecular weight chitosan (LMWCH) on various stages of P. aeruginosa ATCC 10145 biofilm formation and eradication, as well as on production of other virulence factors. LMWCH is a well-known naturally occurring agent with a vast antimicrobial spectrum, which has already found application in various fields of medicine and industry. LMWCH at a concentration of 40 mg/L was able to completely prevent biofilm formation. At a concentration of 60 mg/L, this agent was capable to eradicate already formed biofilm in most studied times of addition (2-12 h of cultivation). LMWCH (50 mg/L) was also able to suppress pyocyanin production when added 2 and 4 h after cultivation. The treatment resulted in reduced formation of cell clusters. LMWCH was proved to be an effective antibiofilm agent worth further clinical research with the potential to become a novel drug for the treatment of P. aeruginosa infections.

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RESUMEN Aunque el sistema respiratorio resulta el más afectado por la COVID-19, hoy conocemos que también predispone a la enfermedad tromboembólica, debido a la excesiva inflamación, activación plaquetaria, disfunción endotelial y estasis que suele ocasionar. La aplicación profiláctica de heparinas de bajo peso molecular ha sido una de las principales recomendaciones en pacientes hospitalizados por esta emergencia sanitaria, práctica no exenta de eventos secundarios, y que tiene entre sus complicaciones más graves la trombocitopenia. Con el propósito de alertar sobre la aparición de esta entidad y evitar mayores complicaciones, se expone un caso en el cual se constató trombocitopenia luego de recibir siete dosis de enoxaparina, y que luego de 48 horas de suspenderse esta, comenzó el ascenso progresivo del número de plaquetas, hasta alcanzar sus niveles de normalidad.

ABSTRACT Although the respiratory system is the most affected by COVID-19, today we know that it also predisposes to thromboembolic disease, due to the excessive inflammation, platelet activation, endothelial dysfunction and stasis that it usually causes. The prophylactic application of low molecular weight heparins has been one of the main recommendations in patients hospitalized for this health emergency, a practice that is not exempt from secondary events, and which has thrombocytopenia among its most serious complications. In order to alert about the appearance of this entity and avoid further complications, a case is presented in which thrombocytopenia was found after receiving seven doses of enoxaparin, and after 48 hours of suspending this, the progressive rise of platelets in number began, until they reach their normal levels.