Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 5 de 5
Filter
1.
Stud Hist Philos Sci ; 92: 45-55, 2022 04.
Article in English | MEDLINE | ID: covidwho-1665463

ABSTRACT

Twentieth-century medicine saw the remarkable rise of complex machines and infrastructures to process blood for medical purposes, such as transfusion, dialysis, and cardiac surgery. Instead of attributing these developments to technological ingenuity, this article argues for the primacy of material encounters as a promising focal point of medical historiography. In fact, blood's special properties consistently clashed with most materials used in medical practice, provoking a series of material exchanges. Drawing on a combination of epistemological and network approaches, three exemplary cases are presented to examine blood's encounters with plastics, plant and animal extracts: William M. Bayliss's (1860-1926) injections of dissolved gum acacia to expand diminished blood volume; Charles H. Best's (1899-1978) production of the anticoagulant heparin from animal organs; and the preservation of fragile blood cells by silicone coatings inside of John H. Gibbon Jr.'s (1903-1973) heart-lung machine. The case studies demonstrate how the complementarity of blood and these materials produced hybridizations between medicine and a range of industrial branches, from colonial forestry and meatpacking to commercial chemistry. In this light, the paper concludes by discussing the dependencies of today's healthcare environments on globally distributed, capitalistically appropriated resources in the face of crises like the COVID-19 pandemic.


Subject(s)
Blood , Medicine , Plastics , Animals , Blood Chemical Analysis , Blood Physiological Phenomena , History, 20th Century , Humans , Plant Extracts , Plastics/chemistry
2.
Int J Mol Sci ; 22(24)2021 Dec 17.
Article in English | MEDLINE | ID: covidwho-1580691

ABSTRACT

Although blood-heart-barrier (BHB) leakage is the hallmark of congestive (cardio-pulmonary) heart failure (CHF), the primary cause of death in elderly, and during viral myocarditis resulting from the novel coronavirus variants such as the severe acute respiratory syndrome novel corona virus 2 (SARS-CoV-2) known as COVID-19, the mechanism is unclear. The goal of this project is to determine the mechanism of the BHB in CHF. Endocardial endothelium (EE) is the BHB against leakage of blood from endocardium to the interstitium; however, this BHB is broken during CHF. Previous studies from our laboratory, and others have shown a robust activation of matrix metalloproteinase-9 (MMP-9) during CHF. MMP-9 degrades the connexins leading to EE dysfunction. We demonstrated juxtacrine coupling of EE with myocyte and mitochondria (Mito) but how it works still remains at large. To test whether activation of MMP-9 causes EE barrier dysfunction, we hypothesized that if that were the case then treatment with hydroxychloroquine (HCQ) could, in fact, inhibit MMP-9, and thus preserve the EE barrier/juxtacrine signaling, and synchronous endothelial-myocyte coupling. To determine this, CHF was created by aorta-vena cava fistula (AVF) employing the mouse as a model system. The sham, and AVF mice were treated with HCQ. Cardiac hypertrophy, tissue remodeling-induced mitochondrial-myocyte, and endothelial-myocyte contractions were measured. Microvascular leakage was measured using FITC-albumin conjugate. The cardiac function was measured by echocardiography (Echo). Results suggest that MMP-9 activation, endocardial endothelial leakage, endothelial-myocyte (E-M) uncoupling, dyssynchronous mitochondrial fusion-fission (Mfn2/Drp1 ratio), and mito-myocyte uncoupling in the AVF heart failure were found to be rampant; however, treatment with HCQ successfully mitigated some of the deleterious cardiac alterations during CHF. The findings have direct relevance to the gamut of cardiac manifestations, and the resultant phenotypes arising from the ongoing complications of COVID-19 in human subjects.


Subject(s)
COVID-19/complications , Heart Failure/metabolism , Heart/virology , Animals , Blood/virology , Blood Physiological Phenomena/immunology , COVID-19/physiopathology , Cardiomegaly/metabolism , Cardiovascular Diseases/metabolism , Cardiovascular Physiological Phenomena/immunology , Disease Models, Animal , Endothelium/metabolism , Heart/physiopathology , Heart Failure/virology , Hydroxychloroquine/pharmacology , Male , Matrix Metalloproteinase 9/drug effects , Matrix Metalloproteinase 9/metabolism , Mice , Mice, Inbred C57BL , Muscle Cells/metabolism , Myocardium/metabolism , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Ventricular Remodeling/physiology
3.
PLoS One ; 16(9): e0258018, 2021.
Article in English | MEDLINE | ID: covidwho-1443853

ABSTRACT

BACKGROUND: Data of critically ill COVID-19 patients are being evaluated worldwide, not only to understand the various aspects of the disease and to refine treatment strategies but also to improve clinical decision-making. For clinical decision-making in particular, prognostic factors of a lethal course of the disease would be highly relevant. METHODS: In this retrospective cohort study, we analyzed the first 59 adult critically ill Covid-19 patients treated in one of the intensive care units of the University Medical Center Regensburg, Germany. Using uni- and multivariable regression models, we extracted a set of parameters that allowed for prognosing in-hospital mortality. RESULTS: Within the cohort, 19 patients died (mortality 32.2%). Blood pH value, mean arterial pressure, base excess, troponin, and procalcitonin were identified as highly significant prognostic factors of in-hospital mortality. However, no significant differences were found for other parameters expected to be relevant prognostic factors, like low arterial partial pressure of oxygen or high lactate levels. In the multivariable logistic regression analysis, the pH value and the mean arterial pressure turned out to be the most influential prognostic factors for a lethal course.


Subject(s)
COVID-19/blood , COVID-19/mortality , Adult , Aged , Arterial Pressure/physiology , Blood Physiological Phenomena , Blood Pressure/physiology , Cohort Studies , Critical Illness/mortality , Female , Germany/epidemiology , Hospital Mortality/trends , Humans , Hydrogen-Ion Concentration , Intensive Care Units/trends , Male , Middle Aged , Mortality/trends , Prognosis , Retrospective Studies , Risk Factors , SARS-CoV-2/pathogenicity
4.
Ann Emerg Med ; 78(4): 511-514, 2021 10.
Article in English | MEDLINE | ID: covidwho-1293546

ABSTRACT

Vaccine-induced thrombotic thrombocytopenia is a newly described disease process in the setting of expanding access to COVID-19 vaccination. The United States Centers for Disease Control and Prevention recommends treatment with an alternative to heparin in patients suspected of having vaccine-induced thrombotic thrombocytopenia. At this time there have been no reported outcomes from the treatment of vaccine-induced thrombotic thrombocytopenia with bivalirudin as a heparin alternative. We describe the early outcomes from the treatment of vaccine-induced thrombotic thrombocytopenia with bivalirudin as a heparin alternative. A 40-year-old Caucasian woman was found to have thrombocytopenia, cerebral venous sinus thrombosis, and pulmonary embolism following vaccination for COVID-19 with Ad26.COV2.S. She exhibited a steady rise in platelet count: 20×109/L at hospital day 0, 115×109/L at discharge on hospital day 6, and 182×109/L on outpatient follow-up on day 9. While the patient exhibited a transient drop in hemoglobin, there was no clinical evidence of bleeding. This patient did not demonstrate any clinical sequelae of thrombosis, and she reported resolution of her headache. Vaccination with Ad26.COV2.S appears to be associated with a small but significant risk for thrombotic thrombocytopenia within 13 days of receipt. The Centers for Disease Control and Prevention guidance to consider an alternative to heparin was not accompanied by specifically recommended alternatives. A single patient treated with bivalirudin for suspected vaccine-induced thrombotic thrombocytopenia subsequently experienced symptom improvement and a rise in platelet count and did not demonstrate any immediate negative outcomes. A provider may consider bivalirudin as an alternative to heparin in patients with suspected vaccine-induced thrombotic thrombocytopenia following Ad26.COV2.S vaccination, pending more definitive research.


Subject(s)
COVID-19 Vaccines/adverse effects , Fibrinolytic Agents/therapeutic use , Peptide Fragments/therapeutic use , Sinus Thrombosis, Intracranial/drug therapy , Thrombocytopenia/drug therapy , Ad26COVS1 , Adult , Blood Chemical Analysis , Blood Physiological Phenomena , COVID-19/prevention & control , Female , Hirudins , Humans , Pulmonary Embolism/drug therapy , Pulmonary Embolism/etiology , Recombinant Proteins/therapeutic use , Sinus Thrombosis, Intracranial/etiology , Thrombocytopenia/etiology
5.
J Healthc Eng ; 2020: 8862645, 2020.
Article in English | MEDLINE | ID: covidwho-1066956

ABSTRACT

The COVID-19 pandemic has highlighted resource constraints in respiratory support. The oxygen transfer characteristics of a specific hollow fiber membrane dialyser was investigated with a view to repurposing the device as a low-cost, readily available blood oxygenator. Oxygen transfer in a low-flux hollow fiber dialyser with a polysulfone membrane was studied by passing first water and then blood through the dialyser in countercurrent to high-purity oxygen. Oxygen transfer rates of about 15% of the nominal 250 ml (STP)/min of a typical adult oxygen consumption rate were achieved for blood flow rates of 500 ml/min. Using two such dialysis devices in parallel could provide up to 30% of the nominal oxygen consumption. Specific hollow fiber dialysis devices operating with suitable pumps in a veno-venous access configuration could provide a cost-effective and readily available supplementation of respiratory support in the face of severe resource constraints.


Subject(s)
COVID-19/therapy , Oxygenators , Renal Dialysis/instrumentation , Blood Physiological Phenomena , Critical Illness/therapy , Equipment Design , Equipment Reuse , Humans , Models, Biological , Oxygen/metabolism , Pandemics , SARS-CoV-2
SELECTION OF CITATIONS
SEARCH DETAIL