The novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) responsible for the coronavirus disease outbreak initiated in 2019 (COVID-19) has been shown to affect the health of infected patients in a manner at times dependent on pre-existing comorbidities. Reported here is an overview of the correlation between comorbidities and the exacerbation of the disease in patients with COVID-19, which may lead to poor clinical outcomes or mortality. General medical issues are also reviewed, such as the types of symptoms present in people infected with SARS-CoV-2, the long-term effects of COVID-19 disease, and the types of treatment that are currently used.

The nature of the blue color in the iodine-starch reaction is still a matter of debate. Some textbooks still invoke charge-transfer bands within a chain of neutral I₂ molecules inside the hydrophobic channel defined by the interior of the amylose helical structure. However, the consensus is that the interior of the helix is not altogether hydrophobic—and that a mixture of I₂ molecules and iodide anions reside there and are responsible for the intense charge-transfer bands that yield the blue color of the “iodine-starch complex”. Indeed, iodide is a prerequisite of the reaction. However, some debate still exists regarding the nature of the iodine-iodine units inside the amylose helix. Species such as I₃^-, I₅^-, I₇^- etc. have been invoked. Here, we report UV-vis titration data and computational simulations using density functional theory (DFT) for the iodine/iodide chains as well as semiempirical (AM1, PM3) calculations of the amylose-iodine/iodide complexes, that (1) confirm that iodide is a pre-requisite for blue color formation in the iodine-starch system, (2) propose the nature of the complex to involve alternating sets of I₂ and I_x^- units, and (3) identify the nature of the charge-transfer bands as involving transfer from the I_x^- σ* orbitals (HOMO) to I₂ σ* LUMO orbitals. The best candidate for the “blue complex”, based on DFT geometry optimizations and TD-DFT spectral simulations, is an I₂-I₅-I₂ unit, which is expected to occur in a repetitive manner inside the amylose helix.

Hemoglobin-based oxygen carriers (HBOCs) represent a promising alternative to traditional blood transfusions, offering the advantages of extended shelf life and avoiding blood compatibility limitations and infection risks. Positive effects of hemoglobin-based oxygen carriers (HBOCs) on hemorrhagic shock have been researched across various animal species, including swine, rats, rabbits, guinea pigs, and dogs. As previously described, HBOCs based on ovine hemoglobin display better efficiency in the context of hemorrhagic shock compared to those based on the more commonly used bovine hemoglobin. This was evidenced through higher survival rates and more favorable histopathological and immunological outcomes. The vascular effects of ovine hemoglobin polymerized with glutaraldehyde exposure included the absence of hypertension, minimal endothelial damage with slight alterations in inducible nitric oxide synthase (iNOS), and reduced vascular inflammation mediated by interleukin-10 (IL-10). Ovine hemoglobin has emerged as a particularly promising raw material for the development of HBOCs, surpassing bovine and human hemoglobin due to its advantages in availability and efficacy. Furthermore, reducing oxidative stress by polymerizing hemoglobin with glutaraldehyde is most effective with ovine hemoglobin compared to bovine hemoglobin. This study evaluates the effectiveness of ovine hemoglobin polymerized with glutaraldehyde in managing hemorrhagic shock in rabbits, with a focus on its ability to maintain blood pressure, support oxygen transport, and assess potential systemic and oxidative responses. Fifteen adult New Zealand white rabbits, divided into three equal groups, were included in this study: a negative control group transfused with colloid solutions, a positive control group treated with autotransfusion, and a group receiving HBOCs. All groups underwent a hemorrhagic shock protocol, with 40% of their total blood volume withdrawn under deep anesthesia, followed by transfusions 30 min later. Vital parameters, including invasive arterial blood pressure, heart rate, and end-tidal CO₂, were measured throughout the experimental procedures. Arterial blood gas samples were collected before the procedures, after hemorrhagic shock induction, and at the conclusion of the transfusion. In summary, HBOCs offer a promising solution for oxygen delivery, but their effects on blood chemistry, particularly CO₂ and lactate levels, must be considered. Although no direct oxygenation issues were observed in experimental models, elevated CO₂ levels and the interference of HBOCs with lactate measurements emphasize the importance of vigilant clinical monitoring. Polymerized hemoglobin provides a non-nephrotoxic alternative, but challenges persist in preventing nitric oxide scavenging and ensuring effective oxygen delivery.