[Progress of anterior subcutaneous internal fixation in the treatment of anterior pelvic ring injury].

Anterior subcutaneous internal fixation (INFIX) is one of the current representatives of minimally invasive fixation of injuries to the anterior pelvic ring. The nail insertion point of this technique is located at the anterior inferior iliac spinous screw, with an angle of 30° outward and 20° backward. Screw in at an angle, and note that the screw head should be above the deep fascia and maintain a safe distance of 20 to 25 mm from the bone surface. Its improved versions include 3 or 4 nails INFIX with added pubic tubercle screws, unilateral INFIX, short-rod INFIX, and double INFIX. These improvements further enhance stability. The lateral femoral cutaneous nerve (LFCN) is relatively easy to be damaged during anatomy, so special attention should be paid during the operation. Biomechanical stability has advantages over external fixation, and its application is flexible. It is not limited to pubic ramus fracture, symphyseal separation, etc. It also plays an important role in combined anterior and posterior ring fixation. It can be combined with posterior sacroiliac screws, iliac lumbar screws, etc. Fixed etc. Good clinical results have also been reported in children, pregnant women, and people with contraindications for subcutaneous connecting rods. In addition, the current application of robots, reduction frames and other technologies has greatly reduced the difficulty of reduction and improved the quality of closed reduction, making it possible to fix complex pelvic fracture. This technique has high reduction quality and is as effective as traditional steel plates. A common complication is LFCN injury. Careful exposure and adjustment of the position and depth of internal fixation during surgery can effectively avoid this complication.

Asymmetric (4+1) Annulations by Cascade Allylation and Transient σ-Alkyl-Pd(II) Initiated Allylic Csp3 -H Activation.

A unique Pd-catalyzed approach for asymmetric (4+1) annulations via cascade allylation and transient σ-alkyl-Pd(II) initiated methylene Csp3 -H activation is reported. The enolate fragment derived from the decarboxylation of vinyl methylene carbonate is crucial to stabilize the key intermediate. These reactions enable the synthesis of various useful dihydrobenzofurans with excellent enantioselectivity, typically >95 : 5 er, and exclusive (Z)-stereoselectivity. Compared with the well-established annulations via Heck-type C-H activations, this protocol showcases a conceptually new way to generate σ-alkyl-Pd(II) species that could initiate challenging asymmetric Csp3 -H activations.

Structural insights into the assembly and energy transfer of the Lhcb9-dependent photosystem I from moss Physcomitrium patens.

In plants and green algae, light-harvesting complexes I and II (LHCI and LHCII) constitute the antennae of photosystem I (PSI), thus effectively increasing the cross-section of the PSI core. The moss Physcomitrium patens (P. patens) represents a well-studied primary land-dwelling photosynthetic autotroph branching from the common ancestor of green algae and land plants at the early stage of evolution. P. patens possesses at least three types of PSI with different antenna sizes. The largest PSI form (PpPSI-L) exhibits a unique organization found neither in flowering plants nor in algae. Its formation is mediated by the P. patens-specific LHC protein, Lhcb9. While previous studies have revealed the overall architecture of PpPSI-L, its assembly details and the relationship between different PpPSI types remain unclear. Here we report the high-resolution structure of PpPSI-L. We identified 14 PSI core subunits, one Lhcb9, one phosphorylated LHCII trimer and eight LHCI monomers arranged as two belts. Our structural analysis established the essential role of Lhcb9 and the phosphorylated LHCII in stabilizing the complex. In addition, our results suggest that PpPSI switches between different types, which share identical modules. This feature may contribute to the dynamic adjustment of the light-harvesting capability of PSI under different light conditions.

[Meta-analysis of the effect of hollow nail and bone plate on Lisfranc injury].

OBJECTIVE: To compare the clinical efficacy of screw and bone plate internal fixation in the treatment of Lisfranc injury. METHODS: The databases of Wanfang, CNKI, Pubmed, EMBASE, VIP, BIOSIS and other databases were retrieved by computer, and the clinical trial literature from January 1, 2000 to August 1, 2021 was retrieved, the methodological quality of the included studies was strictly evaluated and the data were extracted, and the obtained data were meta-analyzed by Revman 5.4 software. RESULTS: Nine randomized controlled trial literature and 10 retrospective cohort studies were included, of which 416 patients in the experimental group were treated with screw internal fixation, and 435 patients in the control group were treated with bone plate internal fixation. Meta-analysis showed that the surgical time of the bone plate internal fixation group was longer than that of the screw internal fixation group [MD=-14.40, 95%CI(-17.21, -11.60), P<0.000 01], the postoperative X-ray anatomical reduction of the bone plate internal fixation group [MD=0.47, 95%CI(0.25, 0.86), P=0.01], the excellent and good rate of postoperative American orthopedic foot and ankle society(AOFAS) foot function score[MD=0.25, 95%CI(0.15, 0.42), P<0.000 01], postoperative AOFAS foot function score [MD=-5.51, 95%CI(-10.10, -0.92), P=0.02] of the bone plate fixation group was better than those of the screw internal fixation group. Two kinds of operation method had no statistical different for postoperative fracture healing time[MD=1.91, 95%CI(-1.36, 5.18), P=0.25], postoperative visual analgue scale(VAS)[MD=0.38, 95%CI(0.09, 0.86), P=0.11], postoperative complications [MD=1.32, 95%CI(0.73, 2.40), P=0.36], the postoperative infection [MD=0.84, 95%CI(0.48, 1.46), P=0.53], the postoperative fracture internal fixation loosening [MD=1.25, 95% CI(0.61, 2.53), P=0.54], the postoperative incidence of traumatic arthritis [MD=1.80, 95%CI(0.83, 3.91), P=0.14]. CONCLUSION: Bone plate fixation has better short-term and medium-term results and lower reoperation rate in the treatment of Lisfranc injury, so it is recommended to use bone plate fixation in the treatment of Lisfranc injury.

The C-terminal domain of MinC, a cell division regulation protein, is sufficient to form a copolymer with MinD.

Assembly of cell division protein FtsZ into the Z-ring at the division site is a key step in bacterial cell division. The Min proteins can restrict the Z-ring to the middle of the cell. MinC is the main protein that obstructs Z-ring formation by inhibiting FtsZ assembly. Its N-terminal domain (MinCN ) regulates the localization of the Z-ring by inhibiting FtsZ polymerization, while its C-terminal domain (MinCC ) binds to MinD as well as to FtsZ. Previous studies have shown that MinC and MinD form copolymers in vitro. This copolymer may greatly enhance the binding of MinC to FtsZ, and/or prevent FtsZ filaments from diffusing to the ends of the cell. Here, we investigated the assembly properties of MinCC -MinD of Pseudomonas aeruginosa. We found that MinCC is sufficient to form the copolymers. Although MinCC -MinD assembles into larger bundles, most likely because MinCC is spatially more readily bound to MinD, its copolymerization has similar dynamic properties: the concentration of MinD dominates their copolymerization. The critical concentration of MinD is around 3 µm and when MinD concentration is high enough, a low concentration MinCC could still be copolymerized. We also found that MinCC -MinD can still rapidly bind to FtsZ protofilaments, providing direct evidence that MinCC also interacts directly with FtsZ. However, although the presence of minCC can slightly improve the division defect of minC-knockout strains and shorten the cell length from an average of 12.2 ± 6.7 to 6.6 ± 3.6 µm, it is still insufficient for the normal growth and division of bacteria.

Impaired bone healing by enoxaparin via inhibiting the differentiation of bone marrow mesenchymal stem cells towards osteoblasts.

INTRODUCTION: Enoxaparin is widely used to prevent venous thromboembolism after orthopedic surgery and has some adverse effects, such as osteoporosis and delay in fracture healing. However, the exact mechanism delaying bone healing by enoxaparin is still unclear. MATERIALS AND METHODS: X-ray and Micro-CT scanning were performed to detect the effects of enoxaparin on bone healing at rat model of bone defeat. CCK-8 assay and flow cytometry were conducted to measure the effects of enoxaparin on bone marrow mesenchymal stem cells (BMSCs). The mRNA/protein levels of osteocalcin (OCN), runt-related transcription factor 2 (Runx2) and bone morphogenetic protein 2 (BMP2) were analyzed by real-time PCR and western blotting, respectively. Alizarin red staining was used to observe the mineralized nodules. RESULTS: Enoxaparin (2000 AXaIU/kg) not only profoundly increased the trabecular separation, but also notably decreased the trabecular bone volume/tissue volume, trabecular thickness, trabecular number and OCN level, in vivo. Additionally, significantly inhibiting proliferation of BMSCs by enoxaparin (1.0 and 10 AXaIU/ml) was detected. The apoptosis and the ratio of G phase cells in enoxaparin (0.1, 1.0 and 10 AXaIU/ml) group were obviously higher than that in control group. While the ratio of S phase cells was downregulated markedly by enoxaparin (0.1,1.0 and 10 AXaIU/ml) compared with the control group. Most importantly, inducing significant decreases of OCN/Runx2 mRNA/protein expression and formation of mineralized nodules by enoxaparin (0.1, 1.0 and 10 AXaIU/ml) were observed compared with the control group. While the notable decreases of BMP2 mRNA/protein level were only detected in enoxaparin (10 AXaIU/ml) group. CONCLUSION: It was suggested that enoxaparin impaired bone healing through suppressing the differentiation of BMSCs towards osteoblasts.

[Clinical effects between cannulated screw and bone plate internal fixation for humeral tuberosity fracture:a Meta analysis].

OBJECTIVE: To compare clinical effect of cannulated screw and bone plate for the treatment of humeral fracture of greater tuberosity. METHODS: From January 2010 to January 2020, clinical trial literatures on the treatment of humeral tuberosity fractures with cannulated screw and bone plate were searched by PubMed, EMbase, Cochrane Library, Wanfang, CNKI, CBM Database, VIP Database and other databases. Independent literature screening, quality evaluation, and data extraction were performed according to inclusion and exclusion criteria. Revman5.2 software was used to perform Meta analysis. RESULTS: Totally 5 clinical randomized controlled trials and 12 cohort studies were selected, including 1 068 patientsin which 559 patients were treated by cannulated screw internal fixation and 509 patients treated by bone plate internal fixation. Meta analysis resluts showed that there were satistical differences in operation time[MD=-23.03, 95% CI(-29.69, -16.36), P<0.000 1], blood loss[MD=-36.39, 95% CI(-53.73, -19.04), P<0.000 1], hospital stay[MD=-1.86, 95%CI(-3.09, -0.64), P=0.003], fracture healing time [MD=-2.23, 95% CI (-4.27, -0.18), P=0.03], postoperative incidence of infection [OR=0.17, 95%CI (0.03, 0.97), P=0.05], failure rate of internal fixation [OR=3.56, 95% CI (1.29, 9.81), P=0.01] bwteen two groups. While there were no differences in postoperative visual analogue scale (VAS)[MD=-1.34, 95% CI (-2.77, 0.09), P=0.07], American Shoulder and Elbow Surgeons(ASES)[MD=0.26, 95% CI(-6.43, 6.96), P=0.94], Constant shoulder score [MD=-4.05, 95% CI(-8.51, 0.42), P=0.08], excellent rate of Constant shoulder score[MD=-1.30, 95% CI(0.46, 3.72), P=0.62], excellent rate of Neer shoulder joint score[OR=2.04, 95% CI(0.97, 4.28), P=0.06], total complication rate[OR=1.50, 95% CI (0.42, 5.35), P=0.53], incidence of postoperative pain[OR=0.74, 95% CI(0.04, 14.49), P=0.84] and incidence of postoperative acromion syndrome [OR=0.88, 95% CI (0.02, 40.63), P=0.95] between two groups. CONCLUSION: Compared with bone plate, cannulated screw for the treatment of humeral fracture of greater tuberosity has advantages of shorter opertaion time, less blood loss, shorter hospital stay, lower incidence rate of postopertaive infection, and more benefit for fracture healing.

Kinetically Controllable Pd-Catalyzed Decarboxylation Enabled [5 + 2] and [3 + 2] Cycloaddition toward Carbocycles Featuring Quaternary Carbons.

A decarboxylative protocol has been developed toward a range of carbocycles. The key success is based on the use of a batch of newly designed cyclic carbonates as substrates that can provide carbon-carbon zwitterion intermediate under palladium catalysis. The kinetics of the reactions are controllable toward either strained seven- or thermodynamically more favored five-membered carbocycles. The release of this chemistry will shed light on the synthesis of complex and valuable cyclic structures.

Visible-light-mediated radical cascade reaction: synthesis of 3-bromocoumarins from alkynoates.

A visible-light-mediated radical addition of alkynoates to generate 3-bromocoumarins by using N-bromosuccinimide as the bromo source has been accomplished. This procedure provides a bromo radical addition/spirocyclization/ester migration cascade reaction under very mild reaction conditions without using any catalyst or strong oxidant and does not need high reaction temperature. Furthermore, the reaction can also be enlarged to the gram scale, and the product 3-bromocoumarins can be further applied in the synthesis of complex compounds.

Bioinspired Collective Syntheses of Iboga-Type Indole Alkaloids.

We present the application of a bioinspired collective synthesis strategy in the total syntheses of seven iboga-type indole alkaloids: (±)-tabertinggine, (±)-ibogamine, (±)-ibogaine, (±)-ibogaine hydroxyindolenine, (±)-3-oxoibogaine hydroxyindolenine, (±)-iboluteine, and (±)-ervaoffines D. In particular, tabertinggine and its congeners serve as iboga precursors for the subsequent biomimetic transformations into other iboga-type alkaloids.