SARS-CoV-2 Mutations and their Viral Variants

Mutations in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) occur spontaneously during replication. Thousands of mutations have accumulated and continue to since the emergence of the virus. As novel mutations continue appearing at the scene, naturally, new variants are increasingly observed. Since the first occurrence of the SARS-CoV-2 infection, a wide variety of drug compounds affecting the binding sites of the virus have begun to be studied. As the drug and vaccine trials are continuing, it is of utmost importance to take into consideration the SARS-CoV-2 mutations and their respective frequencies since these data could lead the way to multi-drug combinations. The lack of effective therapeutic and preventive strategies against human coronaviruses (hCoVs) necessitates research that is of interest to the clinical applications. The reason why the mutations in glycoprotein S lead to vaccine escape is related to the location of the mutation and the affinity of the protein. At the same time, it can be said that variations should occur in areas such as the receptor-binding domain (RBD), and vaccines and antiviral drugs should be formulated by targeting more than one viral protein. In this review, a literature survey in the scope of the increasing SARS-CoV-2 mutations and the viral variations is conducted. In the light of current knowledge, the various disguises of the mutant SARS-CoV-2 forms and their apparent differences from the original strain are examined as they could possibly aid in finding the most appropriate therapeutic approaches.

The effects of Trolox treatment on experimental strangulation ileus

BACKGROUND

Intestinal ischemia-reperfusion injury is a serious and widespread clinical problem. Trolox effectively prevents lipid peroxidation in oxidative stress and protects cell injury. The aim of this study is to investigate the effect of Trolox alone on the intestinal ischemia-reperfusion injury in strangulation ileus model, which has not been investigated previously.

METHODS

Twenty-eight Sprague-Dawley rats randomly divided into four groups were used. Group Laparotomy + Physiological Saline underwent laparotomy and was administered physiological saline; Group Laparotomy + Trolox was administered Trolox. Group Strangulation + Physiological Saline was administered physiological saline before reperfusion following strangulation ileus; Group Strangulation + Trolox was administered Trolox.

RESULTS

Histopathological study was evaluated and catalase, malondialdehyde, superoxide dismutase measurements were performed in intestinal samples. Serum biochemistry parameters were evaluated. The higher grade (grade > or = 2) was significantly observed to decrease in Group Strangulation + Trolox when compared with Group Strangulation + Physiological Saline (p = 0.04). In Group Laparotomy + Trolox, when compared with Group Laparotomy + Physiological Saline, the higher grade was found to be significantly lower (p = 0.03). The catalase values were found to be significantly lower in Group Strangulation + Trolox, when compared with Group Strangulation + Physiological Saline, and in Group Laparotomy + Trolox, when compared with Group Laparotomy + Physiological Saline (p < 0.01).

CONCLUSIONS

Trolox is a powerful antioxidant as well as effectively prevents ischemia-reperfusion injury of the strangulated intestine segment.

Preconditioning-like amelioration of erythropoietin against laparoscopy-induced oxidative injury

BACKGROUND

Laparoscopic surgery has gained wide acceptance for almost every kind of surgical procedure, although it has produced significant oxidative injury to intraabdominal organs depending on the pressure level and the kind of the gas used. The literature describes several preventive measures for decreasing the postlaparoscopic oxidative injury such as low intraabdominal pressure, gasless laparoscopy, and laparoscopic preconditioning. Erythropoietin was shown previously to decrease ischemia-reperfusion injury to the liver. The current study evaluated the effect of erythropoietin against laparoscopy-induced oxidative injury, as compared with laparoscopic preconditioning.

METHODS

For this study, 64 male Spraque-Dawley rats were randomly assigned to one of the following groups. The control group was subjected to a sham operation. The laparoscopy group was subjected to 60 min of pneumoperitoneum. The laparoscopic preconditioning plus laparoscopy group was subjected to 5 min of insufflation and 5 min of desufflation followed by 60 min of pneumoperitoneum. The erythropoietin plus laparoscopy group was subjected to a subcutaneous injection of erythropoietin as a single 1,000-U/kg dose followed by 60 min of pneumoperitoneum. After 45 min of desufflation subsequent to cessation of pneumoperitoneum, blood, liver, and kidney samples were obtained from half of the rats. The other half of the rats were observed for a reperfusion period of 24 h. Tissue and blood samples also were obtained after this period.

RESULTS

Laparoscopy produced significant oxidative injury, as compared with the sham treatment. Laparoscopic preconditioning produced significant amelioration of the ischemic injury. Although erythropoietin administration during the prelaparoscopic period decreased the pneumoperitoneum-induced oxidative injury, the beneficial effect of laparoscopic preconditioning was more pronounced.

CONCLUSION

Laparoscopic preconditioning is more effective than the preischemic administration of erythropoietin in reducing laparoscopy-induced oxidative injury.

Perioperative immunonutrition ameliorates the postoperative immune depression in patients with gastrointestinal system cancer (prospective clinical study in 42 patients)

Cancer surgery is a major challenge for patients to develop immune depression in postoperative period. Several cytokines can depress immune cell subpopulations. Increased cytokine response after surgery is assumed to arise mainly from lipooxygenase pathway acting on membrane arachidonic acid. Therefore; investigators focused their efforts to alter the membrane fatty acid profile by changing the nutritional regimen with epsilon-3 fatty acid supplementation and encouraging results were obtained after surgery. Despite the theoretical and clinical advantage of enteral nutrition many surgeons remain committed to parenteral nutrition for feeding of patients due to maintain bowel rest and fear of anastomosis leakage at the postoperative period. Several studies investigating role of the postoperative immunonutrition reported that beneficial immunological changes were associated with reduction of infectious complications. Interestingly; these findings were observed at least five days after the surgery in which the highest incidence of complications was seen. In this prospective study including 42 patients eligible for curative gastric or colon cancer surgery; we investigated the beneficial effect of enteral immunonutrition (EEN) compared to total parenteral hyperalimentation (TPN) beginning from the preoperative period. Cortisol and CRP levels as stress parameters significantly increased one day after surgery in both groups but they rapidly returned to (on POD1) preoperative baseline level in EEN group whereas these values remained high in the TPN group. Additionally a significant decrease in natural killer (NK) cells and CD8+ levels were observed in both groups. However they recovered on POD3 in EEN group and on POD6 in TPN group. CD4+ subset remained almost same as preoperative value in the TPN group whereas it increased from (%) 40.14 to 46.40, 51.29 and 54.7 on PO 6th hr, POD3 and POD6 in the EEN group. Our findings suggest that preoperative nutrition via the enteral route provided better regulation of postoperative immune system restoration than parenteral nutrition. On the basis of our findings we recommend enteral immunonutrition to be started at the preoperative period rather than postoperatively before a major operation whenever the enteral route is feasible.

Diagnostic value of interleukin-6 and C-reactive protein in acute appendicitis

The aim of this study is prospectively to evaluate the serum C-reactive protein (CRP) and interleukin-6 (IL-6) levels in detection of acute appendicitis in patients with right iliac fossa pain. Data were collected in prospective manner on 102 consecutive patients with right iliac fossa pain. Laparotomy was performed for suspected acute appendicitis for 55 of the 102 patients, of whom 49 patients had appendicitis, 6 patients non-appendicitis (NA), and the other 47 patients had nonspecific abdominal pain (NSAP) and they did not undergo operation. Among those with appendicitis 31 had acute appendix (AA), 8 had gangrenous appendix (GA), and 10 had perforated appendix (PA). The WBC and CRP the mean (SEM) values were significantly different in AA, GA, and PA groups compared with NSAP and NA groups (P < 0.05). Although the mean IL-6 levels were significantly different only in PA group than the others groups (P < 0.05). The sensitivity and specificity of serum CRP measurements were calculated as 96% and 87%, respectively whereas these were 33% and 83% for IL-6 levels for the diagnosis of the acute appendicitis. As a result, measurement of the CRP levels and WBC have an additional diagnostic value on the diagnosis of the acute appendicitis but determination of IL-6 levels which added to the test combination of WBC and CRP, the sensitivity for the diagnosis of the acute appendicitis was not changed whereas the specificity was decreased to 66%.

Cyclosporine nephrotoxicity in the ischemic kidney and the protective effect of pentoxifylline--a study in the rat

In order to prevent cyclosporine nephrotoxicity in the ischemic kidney, pentoxifylline was used in a rat model. Seventy-two rats were divided into six groups according to treatment after right nephrectomy: Group I was the control, group II was treated with 25 mg/kg cyclosporine, group III underwent renal ischemia for 45 min, group IV was given 25 mg/kg cyclosporine and subjected to renal ischemia, and group V was subjected to renal ischemia and given 45 mg/kg pentoxifylline (repeated at 12, 36, and 48 hr), group VI underwent renal ischemia and was then given both cyclosporine and pentoxifylline. BUN, creatinine, and potassium levels were significantly elevated 24 hr after cyclosporine (group II), ischemia (group III), and cyclosporine and ischemia (group IV). Sodium levels remained unaffected. BUN levels normalized in all but groups III and IV after 48 hr. Creatinine levels normalized in all but group IV after 48 hr. Creatinine clearance fell in all groups and remained low even after 48 hr. Pentoxifylline prevented dramatic rises in BUN and creatinine and levels nearly normalized after 48 hr. It also histologically prevented extensive tissue damage seen after ischemia. In conclusion, pentoxifylline has a protective effect upon the kidney when subjected to cyclosporine in the presence of ischemia.