Rabbit Angiotensin-converting Enzyme-2: 3D Structural Reconstruction and Comparison with its Human Analog | Chapter 2 | Chemistry and Biochemistry: Research Progress Vol. 5

The transmembrane glycoprotein angiotensin-converting enzyme-2 (ACE2), currently better known as the receptor for the coronavirus S-protein, has a key role in blood pressure regulation in humans and mammals. The polypeptide chain of ACE2 has two segments, which form a large globular hydrophilic domain with carboxypeptidase catalytic activity, and a small hydrophobic transmembrane collectrin-like segment. To explain on a molecular level the association of the S protein to ACE2 when using rabbits as an animal model for studying the coronavirus infection, it is needed to know the 3D structure of the rabbit protein rACE2. The aim of the research is to reconstruct the 3D structure of the catalytic domain of rACE2 using its human analog hACE2 as a model, considering the differences in the primary amino acid sequences of the two enzymes, which have a high identity: 85%. Tertiary structure alignment of rACE2 and hACE2 catalytic domains discloses a coincidence in the α-helix segments, with minor deviations in two unstructured sections of the polypeptide chains. The pH dependences of the electrostatic component of the free energy of the two proteins have similar courses, but the 3D structure of the rabbit analog is somewhat more stable. The significant resemblance in the structure and thermodynamic properties between rACE2 and hACE2 suggests that rabbits can serve effectively as animal models for investigating blood pressure regulation and coronavirus infection, with the findings extrapolable to humans.

 

Author (s) Details

 

Svetlana H. Hristova
Department of Medical Physics and Biophysics, Medical Faculty, Medical University – Sofia, Zdrave Str. 2, Sofia 1431, Bulgaria and Faculty of Physics, Sofia University, 5 James Bourchier Blvd., 1164 Sofia, Bulgaria.

 

Trifon T. Popov
Medical Faculty, Medical University – Sofia, Zdrave Str. 2, Sofia 1431, Bulgaria.

 

Alexandar M. Zhivkov
Scientific Research Center, “St. Kliment Ohridski” Sofia University, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria.

 

 Please see the book here:- https://doi.org/10.9734/bpi/cbrp/v5/4676

Ocular Alterations in Severe COVID-19 Patients with Invasive Mechanical Ventilation and Prolonged Pronation | Chapter 4 | Advancement and New Understanding in Medical Science Vol. 2

This work was designed to investigate ocular alterations in patients affected by severe COVID-19 who required invasive mechanical ventilation and prolonged pronation to optimize lung ventilation areas.

Conjunctivitis seems to be the initial or only symptom of this pathology, other alterations in the ocular surface are chemosis, epiphora and ocular secretions. In the COVID-19 pandemic, the use of intensive care units, prolonged pronation, and invasive mechanical ventilation in the management of complicated patients increased greatly. The study design was descriptive, prospective, and cross-sectional, it was carried out in the Intensive Care Unit of the Specialties Hospital of the XXI Century National Medical Center, Mexican Institute of Social Security during the months of March and May 2021. All patients over 18 years of age, of both sexes with a positive test polymerase chain reaction (PCR) for COVID-19, who had the diagnosis of severe pneumonia associated with SARS-CoV-2 who were under invasive mechanical ventilation and who had more than 16 hours of pronation.

The mean age of the patients was 60 years. 68.9% had comorbidities. The most frequent findings in adnexa were blepharoedema and chemosis. In the ocular fundus, several alterations including cotton-wool lesions, intraretinal hemorrhages and arteriolar vasoconstriction were observed. The effect of the hours of pronation on the frequency of retinal alterations was statistically significant the group of patients without changes against those who had more than two retinal alterations. Having more than 145 hours of pronation increases the risk of having more than two retinal alterations. Intraocular pressure increased in pronation by 61 % with P < 0.05. In COVID-19 pneumonia that causes a critical state, it has been seen that there is a proinflammatory and thrombotic state and tissue ischemia due to decreased oxygen distribution, which is related to the development of multi-organ failure and this in turn.

The ocular alterations in patients with COVID-19 under invasive mechanical ventilation and prolonged pronation range from the ocular adnexa to the alterations in the fundus of the eye.

The relevance of this study lies in the fact that the patients were examined during the most severe period of the disease, where more systemic ischemic alterations could have manifested. These results suggest the need to implement a protocol for the primary and secondary prevention of ocular complications in patients with COVID-19, but which may be useful for patients who must remain in prolonged pronation for other medical indications.

Author(s) Details:

Zaira Lizette Jiménez Díaz,
Ophthalmology Service, Specialties Hospital, XXI Century National Medical Center, Mexican Institute of Social Security, Mexico City, Mexico.

Julio Alejandro Blanco D´Mendieta,
Ophthalmology Service, Specialties Hospital, XXI Century National Medical Center, Mexican Institute of Social Security, Mexico City, Mexico.

Arturo Carrasco Quiroz,
Ophthalmology Service, Specialties Hospital, XXI Century National Medical Center, Mexican Institute of Social Security, Mexico City, Mexico.

Lizbeth Karina Blanco D´Mendieta,
Ophthalmology Service, Specialties Hospital, XXI Century National Medical Center, Mexican Institute of Social Security, Mexico City, Mexico.

José D. Méndez,
Medical Research Unit in Metabolic Diseases, Cardiology Hospital, XXI Century National Medical Center, Mexican Institute of Social Security, Mexico City, Mexico.

Please see the link here: https://stm.bookpi.org/ANUMS-V2/article/view/13090

Involution Receptive Field Network for COVID-19 Diagnosis | Chapter 3 | New Trends in Physical Science Research Vol. 6

 Since its outbreak, COVID-19, a brand-new viral disease that causes severe pneumonia-related respiratory failure, has been sweeping the globe. The Community-Acquired Pneumonia (CAP), Normal, and COVID-19 Computed Tomography (CT) scan pictures are identified using the Involution Receptive Field Network from the Large COVID-19 CT scan slice dataset. N-pair contrastive loss is included during the network's training in order to improve the embedding representation for CT scan slices in the latent dimension. In order to enhance feature map extraction, the lightweight Involution Receptive Field Network-Medium (InRFNet-M) is presented. It is both channel-neutral and spatially specific. The assessment findings for the InRFNet-M model show a high level of validation accuracy (99 percent). The suggested InRFNet-M: Involution Receptive Field Network-Medium has shown effective classification with good accuracy and recall scores.

Author(s) Details:

M. Dhruv,
CKM VIGIL Pvt Ltd, Hyderabad, Telangana, India.

R. Sai Chandra Teja,
CKM VIGIL Pvt Ltd, Hyderabad, Telangana, India.

R. Sri Devi,
Department of Anesthesiology, Sri Venkateswara Institute of Medical Sciences SVIMS Tirupati, Chittor District, Andhra Pradesh, India.

S. Nagesh Kumar,
Department of Surgical Oncology, Sri Venkateswara Institute of Medical Sciences SVIMS Tirupati, Chittor District, Andhra Pradesh, India.

Please see the link here: https://stm.bookpi.org/NTPSR-V6/article/view/7209