RESUMEN
Mycobacterium tuberculosis has seen tremendous success as it has developed defenses to reside in host alveoli despite various host-related stress circumstances. Rv1636 is a universal stress protein contributing to mycobacterial survival in different host-derived stress conditions. Both ATP and cAMP can be bound with the Rv1636, and their binding actions are independent of one another. ß-Amyrin, a triterpenoid compound, is abundant in medicinal plants and has many pharmacological properties and broad therapeutic potential. The current study uses biochemical, biophysical, and computational methods to define the binding of Rv1636 with ß-Amyrin. A substantial interaction between ß-Amyrin and Rv1636 was discovered by molecular docking studies, which helped decipher the critical residues involved in the binding process. VAL60 is a crucial residue found in the complexes of both Rv1636_ß-Amyrin and Rv1636-ATP. Additionally, the Rv1636_ß-Amyrin complex was shown to be stable by molecular dynamics simulation studies (MD), with minimal changes observed during the simulation. In silico observations were further complemented by in vitro assays. Successful cloning, expression, and purification of Rv1636 were accomplished using Ni-NTA affinity chromatography. The results of the ATPase activity assay indicated that Rv1636's ATPase activity was inhibited in the presence of various ß-Amyrin concentrations. Additionally, circular dichroism spectroscopy (CD) was used to examine modifications to Rv1636 secondary structure upon binding of ß-Amyrin. Finally, isothermal titration calorimetry (ITC) advocated spontaneous binding of ß-Amyrin with Rv1636 elucidating the thermodynamics of the Rv1636_ß-Amyrin complex. Thus, the study establishes that ß-Amyrin binds to Rv1636 with a significant affinity forming a stable complex and inhibiting its ATPase activity. The present study suggests that ß-Amyrin might affect the functioning of Rv1636, which makes the bacterium vulnerable to different stress conditions.
RESUMEN
BACKGROUND: Constipation is a common problem after surgery for anorectal malformations (ARMs), especially in patients having preserved rectosigmoid after pull-down surgery. Here, we present our experience with patients having constipation after surgery for ARMs and briefly discuss its management. MATERIALS AND METHODS: We retrospectively reviewed electronic operative and follow-up data from January 2015 to December 2019 of all patients having constipation after surgery for ARMs. RESULTS: A total of 77 patients were included in the study. The median age was 60 months, and thirty patients were male. Primary diagnoses were rectourethral fistula (26; 33.77%), vestibular fistula (25; 32.47%), perineal fistula/ectopic anus (18; 23.38%), rectovaginal fistula (4; 5.19%) and imperforate anus without fistula (4; 5.19%). Anal stenosis was found in 20 (25.97%) patients, posterior ledge with an adequate anal opening in 5 (6.49%), displaced anus in 4 (5.19%) but no obvious problem found in 48 (62.34%) patients. Non-operative management was successful in 75.44% (43 out of 57) of patients. Surgery was performed in 32 out of 77 patients (41.56%) with no mortality. Forty-three (72.88%) patients are continent, stayed clean, but 16 (27.19%) patients still need some sort of laxative/bowel wash/enema intermittently (Grade I/II constipation). Incidence of constipation was higher in patients operated through anterior sagittal route (27.58%) than posterior sagittal route (23.94%), but it was not statistically significant (P = 0.479). Follow-up ranged from 3 months to 5 years. CONCLUSION: Constipation is a common problem after ARMs surgery, especially in patients having preserved rectosigmoid after pull-down surgery. It is advisable to create relatively larger neoanus after pull through with early practice of neoanus dilatation, especially in redo cases. Repeated counselling, laxatives and dietary manipulations should begin at the first sign of constipation.