Tuning the Envelope Structure of Enzyme Nanoreactors for In Vivo Detoxification of Organophosphates

Encapsulated phosphotriesterase nanoreactors show their efficacy in the prophylaxis and post-exposure treatment of poisoning by paraoxon. A new enzyme nanoreactor (E-nRs) containing an evolved multiple mutant (L72C/Y97F/Y99F/W263V/I280T) of Saccharolobus solfataricus phosphotriesterase (PTE) for in vivo detoxification of organophosphorous compounds (OP) was made. A comparison of nanoreactors made of three- and di-block copolymers was carried out. Two types of morphology nanoreactors made of di-block copolymers were prepared and characterized as spherical micelles and polymersomes with sizes of 40 nm and 100 nm, respectively. The polymer concentrations were varied from 0.1 to 0.5% (w/w) and enzyme concentrations were varied from 2.5 to 12.5 μM. In vivo experiments using E-nRs of diameter 106 nm, polydispersity 0.17, zeta-potential -8.3 mV, and loading capacity 15% showed that the detoxification efficacy against paraoxon was improved: the LD50 shift was 23.7xLD50 for prophylaxis and 8xLD50 for post-exposure treatment without behavioral alteration or functional physiological changes up to one month after injection. The pharmacokinetic profiles of i.v.-injected E-nRs made of three- and di-block copolymers were similar to the profiles of the injected free enzyme, suggesting partial enzyme encapsulation. Indeed, ELISA and Western blot analyses showed that animals developed an immune response against the enzyme. However, animals that received several injections did not develop iatrogenic symptoms.

Unravelling the Therapeutic Potential of Antibiotics in Hypoxia in a Breast Cancer MCF-7 Cell Line Model

Antibiotics inhibit breast cancer stem cells (CSCs) by suppressing mitochondrial biogenesis. However, the effectiveness of antibiotics in clinical settings is inconsistent. This inconsistency raises the question of whether the tumor microenvironment, particularly hypoxia, plays a role in the response to antibiotics. Therefore, the goal of this study was to evaluate the effectiveness of five commonly used antibiotics for inhibiting CSCs under hypoxia using an MCF-7 cell line model. We assessed the number of CSCs through the mammosphere formation assay and aldehyde dehydrogenase (ALDH)-bright cell count. Additionally, we examined the impact of antibiotics on the mitochondrial stress response and membrane potential. Furthermore, we analyzed the levels of proteins associated with therapeutic resistance. There was no significant difference in the number of CSCs between cells cultured under normoxic and hypoxic conditions. However, hypoxia did affect the rate of CSC inhibition by antibiotics. Specifically, azithromycin was unable to inhibit sphere formation in hypoxia. Erythromycin and doxycycline did not reduce the ratio of ALDH-bright cells, despite decreasing the number of mammospheres. Furthermore, treatment with chloramphenicol, doxycycline, and tetracycline led to the overexpression of the breast cancer resistance protein. Our findings suggest that hypoxia may weaken the inhibitory effects of antibiotics on the breast cancer model.

[Method of repair of anterior abdominal wall defects in children]

Experimental studies were conducted on 60 cadavers of children whose ages ranged from 0 to 14 years. A defect measuring 6-10 cm was formed in the muscles of the anterior abdominal wall (an approximate model of a hiatal opening). Several rows of crimping sutures were then applied to the aponeurosis of the rectus abdominis muscle above and below the defect. The force of stretching of the edges of the defect was studied by an elaborated tensiometric device after application of each row of crimping sutures. It was found that application of two or three rows of crimping sutures above and below the ventral defect ensures reliable decrease of the stretching load exerted on its edges and allows them to be sutured without tension. The optimal zones in the operative field for applying the crimping sutures were also determined. On the basis of experimental study the authors developed and used in the clinic a method for autoplasty of ventral hernias based principally on placing sutures through the edges of the ventral defect only after their approximation, after preliminary removal of the stretching load experienced by the laparotomic wound. The authors used this method of plasty successfully in 9 children with ventral hernias whose ages ranged from 2 to 14 years.

[New instruments for pediatric cardiovascular surgery]

The new instruments well adapt anatomical structures of children. Such features as specific dimensions and configuration, light weight, and easy in operation make them suitable for wide application in pediatric surgery.

[Forceps for the kidney pedicle in newborn and young infants]

Medical instruments for newborns and infants are newly developed the dimensions of which carefully follow infantile anatomic and physiologic features. Instruments are characterized by small weight, flexibility, and small dimensions of working parts. This reduces tissue injuries, makes better view of the operative field and optimizes working conditions during surgery.

[Diagnosis of combined developmental disorders of the large intestine and urinary tract in children]

The authors call attention to the importance of directed clinical examination of the urinary secretion system in children with an abnormal development of the large intestine and anorectal zone. In 23.9% of cases the malformations of the large intestine were associated with anomalies in the development or organs of urinary excretion. The symptoms of associated abnormalities in the anorectal zone and urine excretion ducts are described. A scheme for the examination of such patients is proposed.