Effect of Neutrophils Retention Time in Capillaries on Increase in Their Concentration in a Lattice Capillary Network Model

2007 ◽  
Author(s):  
Atsushi Shirai ◽  
Toshiyuki Hayase
Keyword(s):  
Immune System ◽  
Network Model ◽  
Host Defense ◽  
Retention Time ◽  
Systemic Circulation ◽  
Capillary Network ◽  
Know How ◽  
Pulmonary Capillary ◽  
And Behavior ◽  
Normal Lungs

Neutrophils are known as the most popular cells in leukocytes, and play important roles in immune system. They are retained in pulmonary capillary network even in normal lungs, causing higher concentration than in systemic circulation due to their low deformability [1]. The lungs can be a route for pathogenic substances to invade the host, since thickness of septa which separates blood and outer air is extremely thin. However, the highly concentrated neutrophils are thought to be effectively recruited to the sites of inflammation for the host defense. Therefore, it is essential to know how neutrophils flow in pulmonary capillary microvasculature for the understanding of their functions and behavior in immune system.

Effect of Retention Time of Neutrophils in Alveolar Capillaries on Increase in Their Concentration in the Capillary Network

2007 ◽  
Author(s):  
A. Shirai ◽  
T. Hayase
Keyword(s):  
Retention Time ◽  
Concentration Ratio ◽  
Systemic Circulation ◽  
Capillary Network ◽  
Dominant Factor ◽  
Numerical Result ◽  
Cell Property ◽  
Capillary Bed ◽  
The Relationship ◽  
Alveolar Capillary

It is said that neutrophils, a kind of leukocytes, can be retained in pulmonary alveolar capillary bed, even in normal lungs, resulting in higher concentration than in systemic circulation due to their relatively low deformability, and the concentrated neutrophils help the lung to effectively eliminate the enemies invading from outer air. The authors have developed a model to simulate the flow of neutrophils through an alveolar capillary network, considering the cells’ low deformability as the dominant factor for the retention. Flow of a suspension of neutrophils in plasma through a simplified lattice alveolar capillary network model was numerically simulated to investigate the effect of the retention on the increase in the concentration ratio of the cells between in the network and in the suspension. The numerical result showed that the ratio was lower than the experimentally obtained value. Other possible factors to influence the cell’s retention time are friction and adhesion of the cell on the endothelium. In the last study, effect of the retention time of the cells in individual capillary segments on the increase in the concentration ratio was investigated to suggest the ratio may have an upper limit no matter how long the retention time is extended. In this paper, the authors investigated the contribution of various parameters which affect transit time of a neutrophil through a single capillary segment to the relationships between the retention time and the concentration ratio. Finally, it was shown that the number of cells in the network increased to approach a finite value as the increase in the coefficient, independent of the cell property, concentration of the cells in the suspension or the capillary shape. Transition of the relationship was changed with the parameters.

Assessment of Risk Factors for Severe Coronavirus Disease 2019 among Iranian Patients

2020 ◽  
Keyword(s):  
Risk Factors ◽  
Immune System ◽  
Medical Records ◽  
Critical Role ◽  
Diabetic Patients ◽  
Medication History ◽  
Epidemiological Features ◽  
Hookah Smoking ◽  
And Behavior ◽  
Iranian Patients

Background: The outbreak of Coronavirus Disease 2019 (COVID-19) has led to a major concern for those who are more vulnerable to infections. Objectives: This study aimed to evaluate the most important risk factors for severe COVID-19 pneumonia. Methods: This retrospective study included information on clinical and epidemiological features of 105 patients with severe COVID-19 pneumonia hospitalized in Tajrish Hospital, Tehran, Iran. Initially, the medical records of the patients were investigated, and an interview was conducted based on a pre-prepared checklist to seek information about symptoms, past medical history, medication history, and behavior before hospitalization. Results: Out of 105 participants, 76 (72.5%) cases were male, and 54 (51.4%) patients were older than 54 years old. The majority of the patients (n=18; 17.1%) had both hypertension and diabetes (n=12; 11.4%). Metformin (n=36; 34.3%) was the most used medication amongst the studied patient. In addition, 24 (22.9%) patients were recreational hookah smokers, and the majority (75%) of them were under the age of 46 years old. Eventually, 19 patients were excluded from the study, of whom 11 individuals had diabetes, and 10 cases were using metformin. Conclusion: Apparently, hookah smoking played a critical role in the spread of COVID-19 in Iran and has made younger people more susceptible. In addition to older age, the immunosuppressive effects of Metformin seem to make diabetic patients with an impaired immune system more vulnerable to severe COVID-19 pneumonia. More studies on the immune system of vulnerable individuals by identifying their differences can help to protect them.

scholarly journals FGF9 and SHH regulate mesenchymal Vegfa expression and development of the pulmonary capillary network

Development ◽  
2007 ◽  
Vol 134 (20) ◽  
pp. 3743-3752 ◽  
Author(s):  
A. C. White ◽  
K. J. Lavine ◽  
D. M. Ornitz
Keyword(s):  
Capillary Network ◽  
Pulmonary Capillary

scholarly journals Beyond Host Defense: Emerging Functions of the Immune System in Regulating Complex Tissue Physiology

Cell ◽  
2018 ◽  
Vol 173 (3) ◽  
pp. 554-567 ◽  
Author(s):  
Lucille C. Rankin ◽  
David Artis
Keyword(s):  
Immune System ◽  
Host Defense

Metabolic services of intestinal microbiota of swine: metabolism of carbohydrates and bile salts

2022 ◽  
pp. 37-74
Author(s):  
Weilan Wang ◽  
◽  
Tingting Ju ◽  
Michael G. Gänzle ◽  
◽  
...  
Keyword(s):  
Immune System ◽  
Chronic Disease ◽  
Phenolic Compounds ◽  
Intestinal Microbiota ◽  
Host Defense ◽  
Bile Salts ◽  
Pathogenic Microorganisms ◽  
Metabolic Capacity ◽  
Commensal Microbiota ◽  
Major Nutrients

Vertebrate animals are holobionts and their physiology and metabolism are influenced by their commensal microbiota. Gut microbiota and their metabolites play a key role in the host defense against pathogenic microorganisms, shape the immune system, and impact the resistance to chronic disease. The metabolic activity of intestinal microbiota contributes significantly to the conversion of diet components to molecules that can be absorbed and metabolized by the host. The metabolic capacity of the intestinal microbiota by far exceeds the metabolic capacity of the hosts. Collectively, gut microbes support the digestion of the major nutrients, i.e. carbohydrates, proteins and lipids, and impact uptake and conversion of micronutrients, e.g. phenolic compounds and minerals. This chapter provides an overview on the metabolism of carbohydrates and bile salts by pig microbiota.

Simulation model for flow of neutrophils in pulmonary capillary network

2005 ◽  
Vol 13 (4) ◽  
pp. 301-311 ◽  
Author(s):  
Atsushi Shirai ◽  
Ryo Fujita ◽  
Toshiyuki Hayase
Keyword(s):  
Simulation Model ◽  
Capillary Network ◽  
Pulmonary Capillary

scholarly journals Regulatory T Cells, a Potent Immunoregulatory Target for CAM Researchers: The Ultimate Antagonist (I)

2006 ◽  
Vol 3 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Aristo Vojdani ◽  
Jonathan Erde
Keyword(s):  
T Cells ◽  
Immune System ◽  
Regulatory T Cells ◽  
Host Defense ◽  
Western Medicine ◽  
Treg Cells ◽  
Active Suppression ◽  
Beneficial Effects ◽  
The Past ◽  
Powerful Means

Over the past decade, great interest has been given to regulatory T (Treg) cells. A vast body of evidence has shown the existence and highlighted the importance of Treg cells in the active suppression of immune system responses. This form of immunoregulation is the dominant means utilized by the immune system to reach a harmony between reciprocal response processes in order to ensure adequate host defense with minimal host detriment. Therapeutically targeting Treg cells is a direct and powerful means to manipulate the immune system to achieve beneficial effects on various disease pathologies, including allergy, autoimmunity and cancer, as well as the facilitation of organ transplantation. This powerful target for immunoregulation is of much concern to practitioners and researchers of complementary and alternative medicine because it allows a great deal of control and certainty in dealing with the prevalence of debilitating immune system-related disorders for which there has been little remedy outside of Western Medicine.

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