[Comparison of robotic-assisted single-incision-plus-one-port laparoscopic pyeloplasty and single-incision laparoscopic pyeloplasty in the treatment of pediatric ureteropelvic junction obstruction]

Objective: To compare the efficacy of robotic-assisted single-incision-plus- one-port laparoscopic pyeloplasty (R-SILP+1) with single-incision laparoscopic pyeloplasty (SILP) in pediatric ureteropelvic junction obstruction (UPJO). Methods: The clinical data of 47 children with UPJO who underwent surgery from October 2020 to September 2022 in the Department of Pediatric Surgery of Fujian Provincial Hospital were retrospectively analyzed. According to the surgical method chosen by parents, the children were divided into R-SILP+1 group and SILP group. Baseline data, operative time, intraoperative anastomosis time, volume of blood loss, postoperative hospitalization time, complications, total costs, preoperative and postoperative renal parenchymal thickness (PT), anterior posterior diameter of renal pelvis (APD), and differential renal function (DRF) before and after operation were compared between the two groups, and the clinical efficacy of the two kinds of operation was evaluated. Results: Among the 47 children, 27 were in R-SILP+1 group, including 16 males and 11 females, aged (6.6±3.5) years; 20 were in SILP group, including 12 males and 8 females, aged (6.5±3.5) years. The operations were successful in both groups without conversion to open operation. There were no significant differences between the two groups in baseline data, volume of blood loss, complications, APD and PT at postoperative 6 months, APD, PT and DRF at postoperative 12 months (all P>0.05). Compared with the SILP group, the operative time [(153.0±14.4) vs (189.9±32.6) minutes, P<0.001], intraoperative anastomosis time [(68.8±16.8) vs (97.5±12.0) minutes, P<0.001], postoperative hospitalization time [(6.0±1.3) vs (9.0±1.3) d, P<0.001] were shorter, but the total cost was higher[(57 390±7 664) vs (30 183±4 219) yuan RMB, P<0.001]. Conclusions: Compared with the SILP group, R-SILP+1 can achieve considerable efficacy in treating pediatric UPJO, and has certain advantages in shortening operative time, intraoperative anastomosis time, and postoperative hospitalization time. However, the cost is high.

Directional massless Dirac fermions in a layered van der Waals material with one-dimensional long-range order

One or a few layers of van der Waals (vdW) materials are promising for applications in nanoscale electronics. Established properties include high mobility in graphene, a large direct gap in monolayer MoS₂, the quantum spin Hall effect in monolayer WTe₂ and so on. These exciting properties arise from electron quantum confinement in the two-dimensional limit. Here, we use angle-resolved photoemission spectroscopy to reveal directional massless Dirac fermions due to one-dimensional confinement of carriers in the layered vdW material NbSi_0.45Te₂. The one-dimensional directional massless Dirac fermions are protected by non-symmorphic symmetry, and emerge from a stripe-like structural modulation with long-range translational symmetry only along the stripe direction as we show using scanning tunnelling microscopy. Our work not only provides a playground for investigating further the properties of directional massless Dirac fermions, but also introduces a unique component with one-dimensional long-range order for engineering nano-electronic devices based on heterostructures of vdW materials.

Electron standing waves on the GaN(0001)-pseudo (1 × 1) surface: a FT-STM study at room temperature

We report the direct imaging of standing waves on a GaN(0001)-pseudo (1 × 1) metallic surface, which consists of two atomic Ga layers with the top layer incommensurate. Two types of periodic oscillation are observed by scanning tunneling microscopy at room temperature. The longer wavelength standing waves are due to electron scattering by dislocation-induced steps and two-dimensional InN islands. The localized shorter wavelength waves are attributed to a structural transition of the incommensurate Ga bilayer to a tetrahedral Ga bilayer after the growth of the InN islands.

Vortex properties of two-dimensional superconducting Pb films

Using low temperature scanning tunnelling microscopy/spectroscopy (STM/STS) we have investigated the vortex behaviours of two-dimensional superconducting Pb films at different thicknesses. STS at the vortex core shows an evolution of electronic states with film thickness. Transition from the clean limit to the dirty limit of superconductivity is identified, which can be ascribed to the decreased electronic mean free path induced by stronger scattering from the disordered interface at smaller thicknesses. A magnetic field dependent vortex core size is observed even for such a low- κ superconductor. The weak pinning induced by surface defects leads to the formation of a distorted hexagonal vortex lattice.

Atomic-scale imaging and manipulation of ridges on epitaxial graphene on 6H-SiC(0001)

Ridges are observed on epitaxial graphene on 6H-SiC(0001) by scanning tunneling microscopy (STM). Atomic resolution imaging reveals that they are in fact bulged regions of the graphene layer, occurring as a result of bending and buckling to relieve the compressive strain. Furthermore, their length, direction, and distribution can be manipulated, and new ones can even be created by the tip-surface interactions during STM imaging. The lower limit of terrace size for ridge formation is estimated to be approximately 80 nm, and nearly ridge-free graphene film can be obtained on vicinal 3.5 degrees miscut substrates.

Allogeneic mesenchymal stem cell and mesenchymal stem cell-differentiated chondrocyte suppress the responses of type II collagen-reactive T cells in rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is a T-cell-mediated systematic disease and is usually accompanied by articular cartilage damage. In the present study, we explored the effects of bone marrow-derived mesenchymal stem cells (MSCs) and MSC-differentiated chondrocytes (MSC-chondrocytes) on the responses of antigen-specific T cells in RA to type II collagen (CII) to evaluate the potential therapeutic value of MSCs in RA treatment.

METHODS

The effects of both MSCs and MSC-chondrocytes on the proliferation, activation-antigen expression (CD69 and CD25) and cytokine production [interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-10 and IL-4] of CII-reactive T cells in RA patients were investigated with the stimulation of CII or otherwise. CD3/annexin V staining was used to evaluate T-cell apoptosis in the inhibition. The role of transforming growth factor-beta1 (TGF-beta1) underlying the inhibition was also investigated.

RESULTS

MSCs failed to elicit positive responses of CII-reactive T cells, whereas they significantly suppressed CII-stimulated T-cell proliferation and activation-antigen expression in a dose-dependent fashion without inducing T-cell apoptosis. The inhibition was observed even after MSCs were added as late as 3 days after the initiation of stimulation. Moreover, MSCs inhibited both CD4+ and CD8+ T cells from producing IFN-gamma and TNF-alpha, while they up-regulated the levels of IL-10 and restored the secretion of IL-4. TGF-beta1 was confirmed to play a critical role in the inhibition. Throughout our study, MSC-chondrocytes shared similar properties with MSCs.

CONCLUSION

Both MSCs and MSC-chondrocytes suppressed CII-reactive T-cell responses to CII in RA, which suggested that MSCs could be a potential candidate for RA treatment in future if further confirmed in vivo.

Plant regeneration from protoplasts isolated from embryogenic calli of the forage legume Astragalus melilotoides Pall

An efficient and reproducible protocol is described for the regeneration of Astragalus melilotoides protoplasts isolated from hypocotyl-derived embryogenic calli. Maximum protoplast yield (11.74 +/- 0.6x10(5)/g FW) and viability (87.07 +/- 2.8%) were achieved using a mixture of 2% (w/v) Cellulase Onozuka R10, 0.5% (w/v) Cellulase Onozuka RS, 0.5% (w/v) Macerozyme R10, 0.5% (w/v) Hemicellulase, and 1% (w/v) Pectinase, all dissolved in a cell protoplast wash (CPW) salt solution with 13% (w/v) sorbitol. First divisions occurred 3-7 days following culture initiation. The highest division frequency (9.86 +/- 0.68%) and plating efficiency (1.68 +/- 0.05%) were obtained in solid-liquid medium (KM8P) supplemented with 1.0 mg/l 2,4-dichlorophenoxyacetic acid, 0.5 mg/l 6-benzylaminopurine (BA), 0.2 mg/l kinetin, 0.2 M glucose, 0.3 M mannitol and 500 mg/l casein hydrolysate. Upon transfer to MS medium with 0.5 mg/l alpha-naphthaleneacetic acid and 1-2 mg/l BA, the protoplast-derived calli produced plantlets via somatic embryogenesis (56.3 +/- 4.1%) and organogenesis (21.6 +/- 0.6%). Somatic embryos or adventitious shoots developed into well-rooted plantlets on MS medium without any plant growth regulators or supplemented with 3.0 mg/l indole-3-butyric acid, respectively. About 81% of the regenerants survived in soil, and all were normal with respect to morphology and growth characters.

Regeneration of plants from callus tissues of hairy roots induced by Agrobacterium rhizogenes on Alhagi pseudoalhagi

The legume forage Alhagi pseudoalhagi was transformed by the Agrobacterium rhizogenes strain A4 using cotyledon and hypocotyl segments as infection materials. Regenerated plants were achieved from sterile calli derived from hairy roots, which occurred at or near the infection sites. The regenerated plants from hairy root were characterized by normal leaf morphology and stem growth but a shallow and more extensive root system than normal plants. Opine synthesis, PCR and Southern blot confirmed that T-DNA had been integrated into the A. pseudoalhagi genome. Acetosyringone (AS) was found to be vital for successful transformation of A. pseudoalhagi.

[Agrobacterium rhizogenes-mediated transformation and the regeneration of transformants in Alhagi pseudalhagi]

The regenerated shoot segments of Alhagi pseudalhagi were sliced and infected with Agrobacterium rhizogenes strain A4. The hairy roots and transformed calli were obtained through selection on hormone free MS medium. The transformants were cultured on MS medium with 2 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D) and 0.5-1 mg/L 6-benzylaminopurine (6-BA) to induce calli. 3 mg/L 6-BA and 0.5 mg/L naphthalene acetic acid (NAA) were applied for shoot differentiation. Shoots were planted on MS medium with 2 mg/L indole-3-butyric acid (IBA) and produced roots. Opine analysis proved the integration and expression of T-DNA in over 95% hairy roots, 75% transformed calli and transformed plantlets respectively. The 81% hairy root cells had normal chromosome numbers (2n = 18). The alterations of chromosome number were observed. After one year of subculturing, the regeneration ability of transformants was maintained.

[Selection and identification of salt tolerant line of sainfoin from the seeds of first post-flight plants]

Seeds of sainfoin (Onobrychis vicaefolia Scop.) were carried in the recoverable satellite 940703 and recovered from earth orbit from China in 1994. The progeny seeds were obtained by producing in field. The salt tolerant calluses were selected by screening seedling and callus on 1.5% NaCl-containing medium, reviving growth on NaCl- free medium and selecting callus on 1.2% NaCl-containing medium. The salt tolerant line callus maintained the normal ability to regenerate plant. The salt tolerant line callus exhibited cross-resistance to PEG stress. The variant appeared higher efficiency than control to accumulate proline under salt stress, however, under nonstress condition it had lower proline level than control, which suggested that the higher efficiency to synthesize proline under stress condition may be more important than higher level in tissue under nonstress condition. The mechanism of proline synthesis in the selected callus was considered to result from the alteration in gene sensitivity to water regulation at transcription level. Acrylamide gradient electrophoresis showed that new isoenzyme form with MW 175 kD and 75 kD of superoxide dismutase and esterase respectively appeared in salt torlerant callus. It was indicated that the combination of space mutagenesis with tissue culture could be used for the selection of salt tolerant sainfoin line in vitro.

[Molecular identification of intergeneric somatic hybrid plants between alfalfa and sainfoin]

Somatic hybrid plants between alfalfa and sainfoin were regenerated by protoplast fusion and culture. DNA samples of the hybrid plants, hydroxyproline-resistant sainfoin plants, alfalfa cell line transformed with Agrobacterium tumefaciens 702 were isolated with a new and simple method. The hybridity was identified by random amplified polymorphic DNAs and Southern hybridization. Significant differences can be seen in the sequences amplified, which are specific for each parent/primer combination under the amplification conditions used. In 20 random oligonucleotide primers used, six could amplified more DNA fragments and had better polymorphisms. The results suggested that besides containing nuclear substances of two parents, the hybrid genome was inclined to eliminate sainfoin chromosome with DNA reconstruction. However, the somatic genome also could produce the sainfoin-specified DNA fragments which further confirmed by Southern hybridization. The hybrids were asymmetric and had certain regeneration ability just because the intervention of sainfoin DNA.

[Transformation of sainfoin by Agrobacterium rhizogenes LBA9402 Bin19 and regeneration of transgenic plants]

Hypocotyl segments of Onobrychis viciaefolia were transformed by Agrobacterium rhizogenes LBA9402 which harboured pBin19 and pRi1855. Seedling age and preculture time of hypocotyl segments influenced the transformation frequency. Paper electrophoresis revealed that 70% of single hairy root cultures could synthesize agropine. Calli were induced from hairy root segments on MS medium containing 0-9.05 mumol/L 2,4-D and 0-2.22 mumol/L 6-BA at first, then they were transferred onto MS0 medium without kanamycin for regeneration. Constitution and concentration of phytohormones in callus induction media affected subsequent regeneration of calluses on MS0 medium remarkably. Regeneration frequency and shoot number per callus declined when 2,4-D concentration in callus induction media increased from 4.52 to 9.05 mumol/L, while they ascended when 6-BA in callus induction media increased from 0 to 2.22 mumol/L. On MS medium supplemented with 4.52 mumol/L 2,4-D and 2.22 mumol/L 6-BA, only 14.2% hairy root segments could produce calluses, but the regeneration frequency reached 58.1% and the shoot number per callus was 37.2. In 32 analysed plants regenerated from 8 kanamycin resistant hairy root lines, 25 were nptII positive and showed different copy numbers.

[Improved protoplast-derived plants of Astragalus adsurgens through somatic embryogenesis]

Embryogenic callus was obtained only from hypocotyl explants of Astragalus adsurgens and light inhibited the formation of embryogenic callus. A high yield (1.2 x 10(6)/g F. Wt.) of protoplasts with high viability (over 80%) could be isolated from 10-day-old embryogenic callus. Protoplasts were induced to undergo sustained division and to form cell colonies when cultured in agarose-solidified medium (KMP) containing 1/4 strength of mineral salts and supplemented with 1.5 mg/L 2, 4-D, 0.5 mg/L BA and 0.5 mol/L glucose at a plating density of 1.0 x 10(5)mL, where the plating efficinency was 16.8%. Conditioning medium significantly improved the formation of cell colonies. When protoplast-derived colonies were maintained at 4 degrees C for 2 weeks and subsequently transferred onto medium (MS) with 0.1 mg/L NAA and 1.0 mg/L BA, somatic embryogenesis occurred. Frequency of cell colonies producing somatic embryos reached 70%, and the number of somatic embryos per gram cells was over 200. Cultured on hormone-free half-strength MS medium, somatic embryos developed into healthy plantlets with normal chromosome complement.

Regeneration of Astragalus adsurgens via somatic embryogenesis from cell suspension protoplasts

Protoplasts from 4-day-old embryogenic cell suspension cultures of Astragalus adsurgens, when cultured in KM8P medium which ammonium concentration was reduced to 2.5 mmol/L and supplemented with 0.5 mg/L NAA, 1.0 mg/L 2, 4-D, 0.7 mg/L BA and 0.4 mol/L glucose, underwent cell sustained divisions and formed cell colonies at a frequency of 16%-20%. Preplasmolysis or low temperature treatment of suspension cells prior to enzyme incubation enhanced colony formation. Following proliferation on MS medium containing 1.0 mg/L 2, 4-D and 0.5 mg/L BA, cell colonies were cultured on MS medium containing 0.1 mg/L NAA and 1.0 mg/L BA, where approximately 40% of colonies produced somatic embryos ranging in number from 20 to 40 per colony. No significant decrease was found in the potential of somatic embryogenesis when protoplast colonies were obtained from long-term cell suspensions. On hormone-free 1/2 MS medium, somatic embryos developed into intact plants, which showed normal morphology and stable chromosome number.

Induction of apoptosis and suppression of clonogenicity of ovarian carcinoma cells with estrogen mustard

BACKGROUND

This study was conducted to evaluate whether estramustine (estrogen mustard [EM]) is a promising alternative in the treatment of patients with epithelial ovarian carcinoma (OVCA). EM is a microtubule-associated protein (MAP) specific antimicrotubule agent with low toxicity.

METHODS

The authors investigated the ability of EM to induce apoptosis and suppress colony formation of OVCA cells. Paclitaxel was used as a positive control. DNA electrophoresis and terminal deoxynucleotidyl dUTP-X nick end labeling (TUNEL) assays were used to detect internucleosomal DNA fragmentation. Flow cytometry was used to identify apoptotic cells and disturbance of the cell cycle of EM-treated OVCA cells further. Quantitation of detached cultured cells also provided a relative estimate of the apoptotic response of OVCA cells to treatment with EM. The colony formation assay was used to evaluate the effects of EM on clonogenicity.

RESULTS

The effects of EM on four OVCA cell lines in culture were highly similar to those of paclitaxel in causing apoptosis and inhibiting clonogenicity. DNA electrophoresis and TUNEL assays showed that EM induced internucleosomal DNA fragmentation in OVCA cells. Flow cytometry showed changes typical of apoptotic changes and cell cycle block and synchronization at the G2/M-phase. Counting of detached cells showed a log-dose response to EM treatment. The colony formation assay also showed a log-dose response suppression of OVCA cell clonogenicity after treatment with EM.

CONCLUSIONS

EM may be a promising candidate in the clinical treatment of patients with OVCA. The lower toxicity and MAP specific action of EM is a novel chemotherapy for OVCA.

Plant regeneration from protoplasts isolated from callus ofGentiana crassicaulis

Fast growing calli induced from hypocotyl segments ofGentiana crassicaulis were used for preparation of protoplasts. High yields of viable protoplasts were produced in an enzyme solution containing 1-2% cellulase, I% pecfinase, and 0.5% Hemicellulase. Protoplasts were cultured in KM8P medium containing 1 mg/l 2,4-D, 0.5 mg/l 6BA, 500 mg/l LH, 0.5 M glucose and 0.1 M mannitol by the solid-liquid dual layer culture method. First division occurred within 4-5 days of culture at a frequency of 17.8%. Sustained divisions led to callus formation. Periodically diluting the cultures with freshly prepared liquid medium containing 1% glucose was critical for colony formation. Protocolonies about 2 mm in size were transferred onto MS medium supplemented with 3 mg/l ZT, 2 mg/l 6BA, 1 mg/l GA3, 1 mg/l NAA and 6% sucrose to obtain embryogenic calli. Plantlets were regenerated via somatic embryogenesis at high frequency on hormone-free MS Medium.

Mesophyll protoplasts from Solanum melongena var depressum bailey regenerate to fertile plants

Mesophyll protoplasts have been isolated from soil grown plants of Solanum melongena var depressum Bailey and protoplast-derived colonies regenerated in liquid DPD culture medium. Protoplast-derived colonies proliferated on agar-solidified MS culture medium and regenerated shoots which grew to fertile plants in potting compost.