COVID-19: Initial experience of an international group of hand surgeons.

The emergence of the COVID-19 pandemic has severely affected medical treatment protocols throughout the world. While the pandemic does not affect hand surgeons at first glance, they have a role to play. The purpose of this study was to describe the different measures that have been put in place in response to the COVID-19 pandemic by hand surgeons throughout the world. The survey comprised 47 surgeons working in 34 countries who responded to an online questionnaire. We found that the protocols varied in terms of visitors, health professionals in the operating room, patient waiting areas, wards and emergency rooms. Based on these preliminary findings, an international consensus on hand surgery practices for the current viral pandemic, and future ones, needs to be built rapidly.

[New possibilities to increase the results of posttraumatic nerve regeneration with sympathectomy].

AIM: To study the influence of sympathectomy on nerve regeneration in human extremities. MATERIAL AND METHODS: Autoneuroplasty was performed in 86 patients with posttraumatic defects of median and ulnar nerves: in 42 cases in combination with sympathectomy (thoracoscopic clipping of Th3-4 sympathetic ganglions) and in 44 cases without sympathectomy. Computer thermography, laser Doppler flowmetry with spectral wavelet-analysis of blood flow oscillations, ultrasonography of nerve trunks and stimulation electroneuromyography were used. RESULTS AND CONCLUSION: Induced sympathectomy was for the first time shown to have a positive activating influence on the restoration of innervation and tissue trophics in the course of posttraumatic nerve regeneration. The combination of autoneuroplasty with induced sympathectomy contributes to a more complete restoration of motor and sensory nerve fibers, helps to normalize the blood flow in the microvascular bed and thermal topography of the damaged segment of the extremity and support the trophotropic direction of tissue control including the previously denervated area.

[The influence of induced sympathectomy on human peripheral nerves regeneration after autoneuroplasty].

86 patients with posttraumatic defects of median and ulnar nerves were examined. Autoneuroplasty was performed at all of patients: in 42 cases--in combination with sympathectomy (thoracoscopic clipping of Th3-4 sympathetic ganglions), in 44 cases--without sympathectomy. Ultrasonography of nerve trunks, stimulation electroneuromyography, computer thermography, laser Doppler flowmetry with spectral wavelet-analysis of blood flow oscillations were used during checkup. For the first time was shown that induced sympathectomy has positive activating influence on restoring innervation and tissue trophics in the course of posttraumatic nerve regeneration. Combination of autoneuroplasty with induced sympathectomy contributes to a more complete restoration of motor and sensory nerve fibres, helps to normalize blood flow in microvascular bed and thermotopography of the damaged segment of the extremity including the previously denervated area.

[Posterior interosseous flap in pediatric hand reconstructions].

The results of hand reconstructions with posterior interosseous flap were studied in 10 children (4 males and 6 females) aged from 1 year to 13 years old. In 4 cases flap coverage was performed due to acquired posttraumatic hand deformity, in 6 cases reconstruction was assumed for congenital hand deformities. Combined procedures consisted of posterior interosseous flap coverage and other types of microsurgical reconstructions were suggested in all 10 patients. Preoperative color Doppler visualization of the posterior interosseous vessels was mandatory. All flaps were risen under 3.5-4.5X magnification. All flaps survived completely in 3 weeks postoperatively. There were not postoperative complications such as flap's arterial or venous insufficiency, deep infection, or posterior interosseous nerve palsy. Nearly whole group (9 of 10) of patients and/or their parents were satisfied with the esthetic view of the reconstructed hand and donor site of the forearm 1 year postoperatively.

Study of the Structure-Function-Stability Relationships in Yeast D-amino Acid Oxidase: Hydrophobization of Alpha-Helices.

Hydrophobization of alpha-helices is one of the general approaches used for improving the thermal stability of enzymes. A total of 11 serine residues located in alpha-helices have been found based on multiple alignments of the amino acid sequences of D-amino acid oxidases from different organisms and the analysis of the 3D-structure of D-amino acid oxidase from yeast Trigonopsis variabilis (TvDAAO, EC 1.4.3.3). As a result of further structural analysis, eight Ser residues in 67, 77, 78, 105, 270, 277, 335, and 336 positions have been selected to be substituted with Ala. S78A and S270A substitutions have resulted in dramatic destabilization of the enzyme. Mutant enzymes were inactivated during isolation from cells. Another six mutant TvDAAOs have been highly purified and their properties have been characterized. The amino acid substitutions S277A and S336A destabilized the protein globule. The thermal stabilities of TvDAAO S77A and TvDAAO S335A mutants were close to that of the wild-type enzyme, while S67A and S105A substitutions resulted in approximately 1.5- and 2.0-fold increases in the TvDAAO mutant thermal stability, respectively. Furthermore, the TvDAAO S105A mutant showed on average a 1.2- to 3.0-fold higher catalytic efficiency with D-Asn, D-Tyr, D-Phe, and D-Leu as compared to the wild-type enzyme.

Engineering of substrate specificity of D-amino acid oxidase from the yeast Trigonopsis variabilis: directed mutagenesis of Phe258 residue.

Natural D-amino acid oxidases (DAAO) are not suitable for selective determination of D-amino acids due to their broad substrate specificity profiles. Analysis of the 3D-structure of the DAAO enzyme from the yeast Trigonopsis variabilis (TvDAAO) revealed the Phe258 residue located at the surface of the protein globule to be in the entrance to the active site. The Phe258 residue was mutated to Ala, Ser, and Tyr residues. The mutant TvDAAOs with amino acid substitutions Phe258Ala, Phe258Ser, and Phe258Tyr were purified to homogeneity and their thermal stability and substrate specificity were studied. These substitutions resulted in either slight stabilization (Phe258Tyr) or destabilization (Phe258Ser) of the enzyme. The change in half-inactivation periods was less than twofold. However, these substitutions caused dramatic changes in substrate specificity. Increasing the side chain size with the Phe258Tyr substitution decreased the kinetic parameters with all the D-amino acids studied. For the two other substitutions, the substrate specificity profiles narrowed. The catalytic efficiency increased only for D-Tyr, D-Phe, and D-Leu, and for all other D-amino acids this parameter dramatically decreased. The improvement of catalytic efficiency with D-Tyr, D-Phe, and D-Leu for TvDAAO Phe258Ala was 3.66-, 11.7-, and 1.5-fold, and for TvDAAO Phe258Ser it was 1.7-, 4.75-, and 6.61-fold, respectively.

[The efficacy of hand desimpatization after sympatectomy by complex regional pain syndrome].

64 patients operated on the reason of complex regional hand pain syndrome were examined with the use of laser spectral Doppler flowmetry and thermography. 33 patients had thoracoscopic Th3 ganglion clipation; 16 patients had brachial artery and vein perivascular sympathectomy; 15 patients periarterial sympathectomy on the level of brachial artery. Desympathisation (microcirculatory hemodynamic improvement and trophotropic microcirculation regulatory changes) was mostly apparent after thoracoscopic clipation and perivascular desympatisation in comparison with isolated periarterial sympatectomy.

[Interaction of delta sleep-inducing peptide and its analogues with cellular membranes: a structure-function analysis].

The possibility of a correlation between the membrane properties of the delta sleep-inducing peptide (DSIP) and its analogues and their biological activity in vivo was examined by a comparative study of the membrane effects of these peptides. The peptides exhibiting biological activity in vivo were shown to cause a statistically reliable disordering of lipids in thrombocyte plasma membranes similar to the effect of DSIP. The membrane effect of the D-Val2, D-Tyr2, and Tyr1, Pro2 analogues of DSIP had the same bimodal dose dependence characteristic of natural DSIP. Only a slight nonspecific lipid disordering was registered for Trp-Asp-Ala-Ser-Gly-Glu, a biologically inactive hexapeptide analogue. These results indicate a correlation between the biological activity of the peptides during in vivo tests and their membrane properties in vitro. The structure-function relationship was studied within the group of DSIP analogues examined in vitro. The DSIP modeling effect, especially pronounced under the action of stress factors, was suggested to be directly associated with the ability of DSIP to change the dynamic structure of biological membranes.

[Interaction of delta-sleep-inducing peptide with cell membranes in vitro]. / Vzaimodeistvie del'ta-son-indutsiruiushchego peptida s kletochnymi membranami in vitro.

The effect of delta-sleep-inducing peptide (DSIP) on erythrocytic membranes of human donor blood was studied by the spin label and spin probe methods. The spin-labeled derivative of DSIP containing the N-terminal residue of 1-oxyl-2,2,5,5-tetramethylpyrroline-3-carboxylic acid was synthesized. An analysis of the ESR spectra of the spin-labeled DSIP derivative recorded after its incubation with a human erythrocyte suspension at 37 degrees C revealed a decrease in the rotational correlation time (tau c) and molecular order parameter (S) in comparison with the control solutions of the peptide in phosphate buffer (pH 7.4). The application of paramagnetic probes, 5-, 12-, and 16-doxylstearic acids and 3-doxylandrostanol, demonstrated that the introduction of DSIP in an erythrocytic suspension significantly increased the mobility of the hydrophobic area of the membrane bilayer both at a depth of 20-22 A and in the subsurface area (4-6 A). The dependence of these effects on the DSIP concentration was shown to have the form of a curve with well-defined extremes. The maximal disordering of membrane lipids was observed at peptide concentrations of 10(-9) and 10(-6) M. These results suggested that DSIP significantly affected the structure of plasmatic membranes in vitro by changing the physical state of their lipid components.

[Standardization of general hardness in drinking water]. / O normative obshchei zhestkosti v pitévykh vodakh.

Reduction of drinking-water hardness to 7 mg-edv/1 by relevant treatment is suggested in all cases because a higher level of hardness causes an increase of the incidence of some diseases.

[Vascular bed of the fingers in injuries of flexor tendons and arteries]. / Sosudistoe ruslo pal'tsev kisti pri povrezhedniiakh sukhozhilii sgibatelei i arterii.

Active movements of 161 fingers after a tendon suture in the "critical" area have been examined in 36 +/- 1.4 months after injuries. Impairments of the vasculo-neural fascicles have been detected in 61.2% of fingers whose movements did not differ from the movements of the fingers with intact innervation and circulation. Contrast arteriography (in cadaver experiments) of cut wounds of the fingers with disruptions of the tendons and arteries has shown that disruption of both the main arteries with crossing the soft tissues of the palmar and lateral surfaces of 2-5 fingers excludes the arteries distal to the injury from the blood flow. Intact soft tissues could provide the functioning of the collaterals along approximately 10 mm on the proximal phalanx and 6 mm on the middle one. After tendon sutures the tendons regeneration takes place in conditions of intact collateral circulation in cases with wounds of 2-5 fingers, involving injury to one artery, or of the main arteries of 1 finger, or with intact soft tissues on the palm surface of 2-5 fingers.