Visible-light-driven water-soluble zinc oxide quantum dots for efficient control of citrus canker

BACKGROUND

Citrus canker caused by Xanthomonas citri subsp. citri (Xcc) is a devastating bacterial disease that reduces citrus yield and quality, posing a serious threat to the citrus industry. Several conventional chemicals have been used to control citrus canker. However, this approach often leads to the excessive use of chemical agents, can exacerbate environmental pollution and promotes the development of resistant Xcc. Therefore, there is significant interest in the development of efficient and environmentally friendly technologies to control citrus canker.

RESULTS

In this study, water-soluble ZnO quantum dots (ZnO QDs) were synthesised as an efficient nanopesticide against Xcc. The results showed that the antibacterial activity of ZnO QDs irradiated with visible light [half-maximal effective concentration (EC50) = 33.18 μg mL-1] was ~3.5 times higher than that of the dark-treated group (EC50 = 114.80 μg mL-1). ZnO QDs induced the generation of reactive oxygen species (•OH, •O- 2 and 1O2) under light irradiation, resulting in DNA damage, cytoplasmic destruction, and decreased catalase and superoxide dismutase activities. Transcription analysis showed downregulation of Xcc genes related to 'biofilms, virulence, adhesion' and 'DNA transfer' exposure to ZnO QDs. More importantly, ZnO QDs also promoted the growth of citrus.

CONCLUSION

This research provides new insights into the photocatalytic antibacterial mechanisms of ZnO QDs and supports the development of more efficient and safer ZnO QDs-based nanopesticides to control citrus canker. © 2024 Society of Chemical Industry.

Toxicity risk assessment of flupyradifurone for the predatory pirate bug, Orius strigicollis (Poppius) (Heteroptera: Anthocoridae), a biological control agent of Diaphorina citri Kuwayama (Hemiptera: Liviidae)

Diaphorina citri Kuwayama (Hemiptera: Liviidae), commonly known as the Asian citrus psyllid, is a prominent citrus tree pest that serves as a vector for Asian huanglongbing (HLB). The substantial costs incurred by the citrus industry as a consequence of this disease have spurred considerable interest in the combined control of D. citri using insecticides and natural enemies. However, the successful implementation of such integrated pest management strategies is dependent on ensuring the compatibility of using natural enemies in the presence of insecticides. In this regard, we evaluated the lethal and sublethal effects of flupyradifurone on Orius strigicollis (Poppius) (Heteroptera: Anthocoridae), an important predatory biological control agent, in which we assessed the risk of exposure to flupyradifurone under both in- and off-field scenario. The median lethal rate (LR50) value of flupyradifurone against O. strigicollis (9.089 g a.i. ha-1), was found to be significantly lower than the maximum field recommended rate (MFRR, 170 g a.i. ha-1). Additionally, at 0.254 g a.i. ha-1, flupyradifurone was established to significantly prolong the developmental duration of O. strigicollis from the first to third instar nymphs. Although we detected no significant difference in the survival of immature O. strigicollis subjected to 0.064 g a.i. ha-1 and control treatments, survival was significantly lower in 0.127 and 0.254 g a.i. ha-1 treatments. Moreover, whereas there were no significant differences in adult longevity between the 0.127 g a.i. ha-1 and control treatments, we recorded a significant reduction in fecundity. Furthermore, there were reductions in peak life expectancy, reproductive value, finite rate of increase, intrinsic rate of increase, and net reproduction rate in response to exposure to increasing flupyradifurone rate. Additionally, at 0.127 g a.i. ha-1, the mean generation time was significantly longer than that under control conditions. Following simulated exposure to flupyradifurone for 100 days, population of O. strigicollis in the 0.064 g a.i. ha-1 and control treatments were found to be significantly larger than those exposed to 0.127 g a.i. ha-1. On the basis on LR50 evaluations, whereas the risk of exposure risk was unacceptable for O. strigicollis under in-field scenario, it remained acceptable off-field. Nonetheless, the sublethal effect of prolonged exposure to residual flupyradifurone could pose an unacceptable off-field risk to O. strigicollis (e.g., in adjacent habitats). Consequently, the effects of different flupyradifurone exposure scenarios on O. strigicollis should be thoroughly assessed, and reducing the dosage of flupyradifurone could be advantageous for the control of D. citri when combine with augmentative release of O. strigicollis.

Mesoporous Silica Nanoparticles Induce Intracellular Peroxidation Damage of Phytophthora infestans: A New Type of Green Fungicide for Late Blight Control

Nanopesticides are considered to be a promising alternative strategy for enhancing bioactivity and delaying the development of pathogen resistance to pesticides. Here, a new type of nanosilica fungicide was proposed and demonstrated to control late blight by inducing intracellular peroxidation damage to Phytophthora infestans, the pathogen associated with potato late blight. Results indicated that the structural features of different silica nanoparticles were largely responsible for their antimicrobial activities. Mesoporous silica nanoparticles (MSNs) exhibited the highest antimicrobial activity with a 98.02% inhibition rate of P. infestans, causing oxidative stress responses and cell structure damage in P. infestans. For the first time, MSNs were found to selectively induce spontaneous excess production of intracellular reactive oxygen species in pathogenic cells, including hydroxyl radicals (•OH), superoxide radicals (•O₂^-), and singlet oxygen (¹O₂), leading to peroxidation damage in P. infestans. The effectiveness of MSNs was further tested in the pot experiments as well as leaf and tuber infection, and successful control of potato late blight was achieved with high plant compatibility and safety. This work provides new insights into the antimicrobial mechanism of nanosilica and highlights the use of nanoparticles for controlling late blight with green and highly efficient nanofungicides.

Design of a Controlled-Release Delivery Composite of Antibacterial Agent Gatifloxacin by Spherical Silica Nanocarrier

In this study, a spherical silica nanoparticle was explored as a gatifloxacin carrier synthesized by the chemical precipitation method. It was found that there was no new chemical bond formation during the loading process between gatifloxacin and silica, which implies that the binding was driven by physical interaction. In addition, the drug loading and encapsulation efficiency could be improved by appropriately increasing nano-silica content in the loading process. Meanwhile, the release rate of gatifloxacin after loading nano-silica was also improved, suggesting the successful design of a controlled-release delivery composite. The silica nanocarrier could significantly improve the antibacterial performance of Escherichia coli by 2.1 times, which was higher than the pure gatifloxacin. The 24 h bacteriostatic rate was higher than that of a simple mixture of silica nanoparticles and gatifloxacin. Strong reactive oxygen species (ROS) in GAT-SiO₂ NPs suggests that ROS might be associated with bactericidal activity. The synergy between the physicochemical effect and ROS production of this material is proposed as the mechanism of its antibacterial activity, which can also be confirmed by the cell membrane damage observed under electron microscopy and DNA damage experiments. Collectively, our finding indicates that nano-silica microspheres could serve as a promising carrier for the sustained release of gatifloxacin, thereby providing a new carrier design scheme for the improvement of the antibacterial effect.

Effect of Bacillus thuringiensis biomass and insecticidal activity by cultivation with vegetable wastes

Bacillus thuringiensis (Bt) has been regarded as a biopesticide with high efficiency and safety, while it still cannot be popularized and mass-produced because of its high production costs. In the present study, we aimed to develop a cost-effective biopesticide via the secondary use of discharged vegetable wastes as the raw fermentation medium, and the insecticidal activity of Bt strain prepared by this cheap cultivation approach was evaluated. The suitable carbon source, nitrogen source additives and optimal metal ions were screened by the single-factor test, and the optimal combination of additives was determined by orthogonal test and ANOVA analysis. We found that soluble starch (6 g l-1), soya bean meal (6 g l-1), Al3+ (0.4 g l-1) and Fe2+ (0.4 g l-1) were the optimal exogenous additives, and the optimal fermentation conditions were as follows: pH 7.0, temperature of 35°C and aeration of 80 ml/250 ml. Meanwhile, the bioactivity test results showed that the Bt strain prepared by cheap cultivation still exhibited a good insecticidal effect on Helicoverpa armigera compared with the standard LB medium. Collectively, our findings provided a new strategy for vegetable waste utilization with less environmental impact and reduced production cost.

For: Pesticide biochemistry and physiology recG is involved with the resistance of Bt to UV

As an ATP-dependent DNA helicase, RecG can repair DNA replication forks in many organisms. However, knowledge of recG in Bacillus thuringiensis (Bt) is limited. In our previous study, recG was found damaged in Bt LLP29-M19, which was more resistant to ultraviolet light (UV) after exposing Bt LLP29 to UV for 19 generations. To further understand the function of recG in the mechanism of Bt UV resistance, recG was knocked out and recovered with homologous recombination technology in Bt LLP29. Comparing the resistance of the different mutants to UVB, Bt ∆recG-LLP29 lacking recG was found more sensitive to UVB, hydroxyurea (HU) and H₂O₂ than LLP29 and the complementation strain. To compare the expression level of recG in the Bt strains under different UV treatments, Quantitative Real-time PCR (RT-qPCR) of recG was performed in the tested Bt strains, which showed that the expression level of recG in Bt ∆recG-LLP29 was substantially lower than that in the original strain and complementation strain. Interestingly, when exposed to UV for 20 min, RecG expression in both Bt LLP29 and Bt recG-R was the highest. The unwinding activity of recG in Bt LLP29 and the complementation strain were also found higher than that of the recG knockout strain, Bt ∆recG-LLP29. These results demonstrate that recG is involved with the resistance of Bt to UV. These findings not only enhance the understanding of the Bt UV resistance mechanism, but also provide an important theoretical basis for the application of Bt.

SiRNA interfering STAT3 enhances DDP sensitivity in cervical cancer cells

OBJECTIVE

Signal transducer and activator of transcription 3 (STAT3) is an important regulatory protein in the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway, which regulates cell proliferation, apoptosis, and other biological processes. It is closely related to tumor occurrence, progress, and resistance. Cisplatin (DDP) resistant cervical cancer cell line was established by shock induction to investigate the role of STAT3 in cervical cancer cells drug resistance.

PATIENTS AND METHODS

The expression of STAT3 in different chemotherapy response cervical cancer tissues was compared. The cervical cancer was divided into two groups upon STAT3 median level. Cervical cancer cell inhibitory rate by DDP treatment was compared. Western blot was used to detect STAT3 and phosphorylated STAT3 (p-STAT3) expressions in CaSki and CaSki/DDP cells. Cell apoptosis rate was tested by flow cytometry. CaSki/DDP cells were divided into small interfere RNA-normal control (siRNA-NC) group and siRNA-STAT3 group. Cell proliferation was evaluated by EdU staining.

RESULTS

The rate of STAT3 over-expression in cervical cancer patients with no significant chemotherapy response was markedly higher than that with a significant response. The inhibitory effect of DDP on tumor cells derived from patients with low STAT3 expression was significantly higher, while the apoptosis rate was apparently lower than that of CaSki/DDP cells from patients with high STAT3 expression. siRNA-STAT3 transfection significantly reduced the expressions of STAT3 and p-STAT3, decreased cell proliferation, and enhanced cell apoptosis in CaSki/DDP cells.

CONCLUSIONS

STAT3 over-expression is associated with DDP resistance in cervical cancer. Decreasing STAT3 can significantly promote the apoptosis of cervical cancer CaSki cells and decrease the DDP resistance.

[Retrospective analysis of cuffed-tunneled catheters in pediatric patients receiving maintenance hemodialysis]

Objective: To summarize the characteristics of cuffed-tunneled catheters insertion and investigate the values of cuffed-tunneled catheters in pediatric patients. Methods: Between March 2015 and July 2017, all the pediatric patients who received maintenance hemodialysis at least 3 consecutive months in our center were included. Sixteen cuffed-tunneled hemodialysis catheters were inserted in patients for long-term hemodialysis access. The clinical manifestations and complications were retrospectively reviewed. Results: Fifteen pediatric patients with end stage ranal disease (ESRD) were included in this study and they received 16 cuffed-tunneled catheters for long-term vascular access, including 10 males and 5 females; median age at start of catheter insertion was 11.5 (4.2-14.5) years. Body weight was (27.8±8.0)kg (16.0-39.4 kg) . The size and the length of the catheters were based on the height of patients as follows: 28 cm for (115.6±10.6) cm (102.0-130.0 cm) ,36 cm for (148.6±9.9)cm (140.0-167.0 cm) . Cuffed-tunneled catheters outcome: 10 cuffed-tunneled catheters were still functional at the end of the study; 5 catheters were removed after successful kidney transplantation. Catheter failure occurred in 1 out of 16 cuffed-tunneled catheters due to catheter-related infections. The median catheter survival time was 11.9 months (range 3.5-21.3 months). Complications of cuffed-tunneled catheters: Catheter placements operation was successful in 15 cases using ultrasound guidance. No serious complications were observed in any patients receiving catheter inserting operation. The overall rate of catheter-related infections and thrombosis/malposition was 6.3% and 18.7%, respectively. Conclusions: Ultrasound guidance is suggested in pediatric patients during the catheters insertion. The size and the length of the catheters should be based on the height of patients. Cuffed-tunneled hemodialysis catheters could be effectively used for maintenance of hemodialysis vascular access for pediatric patients with ESRD.

Flowerlike Mg(OH)2 Cross-Nanosheets for Controlling Cry1Ac Protein Loss: Evaluation of Insecticidal Activity and Biosecurity

Bacillus thuringiensis (Bt) can produce Cry proteins during the sporulation phase, and Cry protein is effective against lepidopteran, coleopteran, and dipteran insects and nematodes. However, Cry protein tends to be discharged into soil and nontarget plants through rainwater runoff, leading to reduced effective period toward target insects. In the present study, nano-Mg(OH)₂ (magnesium hydroxide nanoparticles, MHNPs) were synthesized to control the loss of Cry1Ac protein and deliver protein to Helicoverpa armigera (Lepidoptera: Noctuidae). The results showed that Cry1Ac protein could be loaded onto MHNPs through electrostatic adsorption, and both MHNPs and Cry protein were stable during the adsorption process. Meanwhile, the Cry1Ac-loaded MHNPs could remain on the surface of cotton leaves, resulting in enhanced adhesion of Cry1Ac protein by 59.50% and increased pest mortality by 75.00%. Additionally, MHNPs could be slowly decomposed by acid medium and MHNPs showed no obvious influence on cotton, Bt, Escherichia coli, and H. armigera. Therefore, MHNPs could serve as an efficient nanocarrier for delivery of Cry1Ac protein and be used as a potential adjuvant for biopesticide in agricultural applications.

The Synergistic Antibacterial Mechanism of Gentamicin-Loaded CaCO 3 Nanoparticles

In the present study, we used CaCO₃ nanoparticles (CCNPs) as carriers to assess the physicochemical characteristics and antibacterial effect of gentamicin sulfate (GS)-loaded CCNPs (CGPs). The results indicated that CCNPs had relatively regular chain-like structure, and the size of the crystallites was around 62.5 nm. FT-IR analysis indicated that the GS could effectively load onto CCNPs. Meanwhile, the dosage of CCNPs would affect the drug loading and entrapment efficiency of GS. CCNPs could prolong the release of GS, and the complete release of GS from CCNPs was extended up to 24 h. Additionally, CCNPs could obviously increase the antibacterial effect of GS. The zeta potential analysis and microscopic investigations indicated that the adsorbed CCNPs could increase the damage level of bacterial cell wall and enhance the permeability of cell membranes, leading to increased bacterial death.

Nano liquid metal for the preparation of a thermally conductive and electrically insulating material with high stability

Dielectric materials typically demonstrate poor thermal conductivity, which limits their application in emerging technologies in integrated circuits, computer chips, light-emitting diode lamps, and other electronic packaging areas. Using liquid metal microdroplets as inclusions to develop thermal interface materials has been shown to effectively improve thermal pathways, but this type of material may become electroconductive with the application of a concentrated compressive stress. In this study, an isotropic nano-liquid metal thermally-conductive and electrically-insulating material (nLM-THEM) is developed by combining a modified polymer and well-dispersed nanoparticles, achieving an ∼50× increase in thermal conductivity over the base polymer. In addition, the thermal conductivity of nLM-THEMs exhibits no significant change with varying humidity and a stable anti-corrosion effect even in direct contact with aluminum. More importantly, nLM-THEMs demonstrate a stable electrical insulating property upon compressive stress, while conventional micro-LM-THEMs exude liquid metal. This exceptional combination of thermal and electrical insulation properties is enabled by the interconnection of uniform and spherical liquid metal nanoparticles to create more thermally-conductive pathways, and surfactant modified nanoparticles ensure excellent electric insulation. Moreover, this material can achieve passive heat exchange through rapid heat dissipation, which demonstrates its great application potential in the electronic packaging area.

Compared to liquid metal (LM) microdroplets based thermally conductive materials (micro-LM-THEMs), nano LM-THEMs (nLM-THEMs) presents a more stable electric insulating property even upon stress, achieving ~50-fold thermal conductivity over base polymer.

The adsorption features between insecticidal crystal protein and nano-Mg(OH)2

Nano-Mg(OH)₂, with low biological toxicity, is an ideal nano-carrier for insecticidal protein to improve the bioactivity. In this work, the adsorption features of insecticidal protein by nano-Mg(OH)₂ have been studied. The adsorption capacity could reach as high as 136 mg g^-1, and the adsorption isotherm had been fitted with Langmuir and Freundlich models. Moreover, the adsorption kinetics followed a pseudo-first or -second order rate model, and the adsorption was spontaneous and an exothermic process. However, high temperatures are not suitable for adsorption, which implies that the temperature would be a critical factor during the adsorption process. In addition, FT-IR confirmed that the protein was adsorbed on the nano-Mg(OH)₂, zeta potential analysis suggested that insecticidal protein was loaded onto the nano-Mg(OH)₂ not by electrostatic adsorption but maybe by intermolecular forces, and circular dichroism spectroscopy of Cry11Aa protein before and after loading with nano-Mg(OH)₂ was changed. The study applied the adsorption information between Cry11Aa and nano-Mg(OH)₂, which would be useful in the practical application of nano-Mg(OH)₂ as a nano-carrier.

Adsorption of Insecticidal Crystal Protein Cry11Aa onto Nano-Mg(OH)2: Effects on Bioactivity and Anti-Ultraviolet Ability

The traditional Bacillus thuringiensis (Bt) formulations for field applications are not resistant to harsh environmental conditions. Hence, the active ingredients of the Bt bioinsecticides could degrade quickly and has low anti-ultraviolet ability in the field, which significantly limits its practical application. In the present study, we developed an efficient and stable delivery system for Bt Cry11Aa toxins. We coated Cry11Aa proteins with Mg(OH)₂ nanoparticles (MHNPs), and then assessed the effects of MHNPs on bioactivity and anti-ultraviolet ability of the Cry11Aa proteins. Our results indicated that MHNPs, like "coating clothes", could effectively protect the Cry protein and enhance the insecticidal bioactivity after UV radiation (the degradation rate was decreased from 64.29% to 16.67%). In addtion, MHNPs could improve the proteolysis of Cry11Aa in the midgut and aggravate the damage of the Cry protein to the gut epithelial cells, leading to increased insecticidal activity against Culex quinquefasciatus. Our results revealed that MHNPs, as an excellent nanocarrier, could substantially improve the insecticidal bioactivity and anti-ultraviolet ability of Cry11Aa.

The Reed-Stanton press rig for the generation of reproducible fingermarks: Towards a standardised methodology for fingermark research

In the search for better or new methods/techniques to visualise fingermarks or to analyse them exploiting their chemical content, fingermarks inter-variability may hinder the assessment of the method effectiveness. Variability is due to changes in the chemical composition of the fingermarks between different donors and within the same donor, as well as to differential contact time, pressure and angle. When validating a method or comparing it with existing ones, it is not always possible to account for this type of variability. One way to compensate for these issues is to employ, in the early stages of the method development, a device generating reproducible fingermarks. Here the authors present their take on such device, as well as quantitatively describing its performance and benefits against the manual production of marks. Finally a short application is illustrated for the use of this device, at the method developmental stages, in an emerging area of fingerprinting research concerning the retrieval of chemical intelligence from fingermarks.

Scaffolding protein Homer1a protects against NMDA-induced neuronal injury

Excessive N-methyl-D-aspartate receptor (NMDAR) activation and the resulting activation of neuronal nitric oxide synthase (nNOS) cause neuronal injury. Homer1b/c facilitates NMDAR-PSD95-nNOS complex interactions, and Homer1a is a negative competitor of Homer1b/c. We report that Homer1a was both upregulated by and protected against NMDA-induced neuronal injury in vitro and in vivo. The neuroprotective activity of Homer1a was associated with NMDA-induced Ca²⁺ influx, oxidative stress and the resultant downstream signaling activation. Additionally, we found that Homer1a functionally regulated NMDAR channel properties in neurons, but did not regulate recombinant NR1/NR2B receptors in HEK293 cells. Furthermore, we found that Homer1a detached the physical links among NR2B, PSD95 and nNOS and reduced the membrane distribution of NMDAR. NMDA-induced neuronal injury was more severe in Homer1a homozygous knockout mice (KO, Homer1a^−/−) when compared with NMDA-induced neuronal injury in wild-type mice (WT, Homer1a^+/+). Additionally, Homer1a overexpression in the cortex of Homer1a^−/− mice alleviated NMDA-induced neuronal injury. These findings suggest that Homer1a may be a key neuroprotective endogenous molecule that protects against NMDA-induced neuronal injury by disassembling NR2B-PSD95-nNOS complexes and reducing the membrane distribution of NMDARs.

Postsynaptic scaffold protein Homer 1a protects against traumatic brain injury via regulating group I metabotropic glutamate receptors

Traumatic brain injury (TBI) produces excessive glutamate, leading to excitotoxicity via the activation of glutamate receptors. Postsynaptic density scaffold proteins have crucial roles in mediating signal transduction from glutamate receptors to their downstream mediators. Therefore, studies on the mechanisms underlying regulation of excitotoxicity by scaffold proteins can uncover new treatments for TBI. Here, we demonstrated that the postsynaptic scaffold protein Homer 1a was neuroprotective against TBI in vitro and in vivo, and this neuroprotection was associated with its effects on group I metabotropic glutamate receptors (mGluRs). Upon further study, we found that Homer 1a mainly affected neuronal injury induced by mGluR1 activation after TBI and also influenced mGluR5 function when its activity was restored. The ability of Homer 1a to disrupt mGluR-ERK signaling contributed to its ability to regulate the functions of mGluR1 and mGluR5 after traumatic injury. Intracellular Ca(2+) and PKC were two important factors involved in the mediation of mGluR-ERK signaling by Homer 1a. These results define Homer 1a as a novel endogenous neuroprotective agent against TBI.

Downregulation of Homer1b/c improves neuronal survival after traumatic neuronal injury

Homer protein, a member of the post-synaptic density protein family, plays an important role in the neuronal synaptic activity and is extensively involved in neurological disorders. The present study investigates the role of Homer1b/c in modulating neuronal survival by using an in vitro traumatic neuronal injury model, which was achieved by using a punch device that consisted of 28 stainless steel blades joined together and produced 28 parallel cuts. Downregulation of Homer1b/c by specific siRNA significantly (p<0.05) alleviated the cytoplasmic calcium levels and neuron lactate dehydrogenase release, and ultimately decreased the apoptotic rate after traumatic neuronal injury compared with non-targeting siRNA control treatment in cultured rat cortical neurons. Moreover, the expression of metabotropic glutamate receptor 1a (mGluR1a) was significantly (p<0.05) reduced in the Homer1b/c siRNA-transfected neurons after injury. Therefore, Homer1b/c not only modulated the mGluR1a-inositol 1,4,5-triphosphate receptors-Ca(2+) signal transduction pathway, but also regulated the expression of mGluR1a in mechanical neuronal injury. These findings indicate that the suppression of Homer1b/c expression potentially protects neurons from glutamate excitotoxicity after injury and might be an effective intervention target in traumatic brain injury.

Cucurbitacin-B inhibits neuroblastoma cell proliferation through up-regulation of PTEN

OBJECTIVE

Cucurbitacins belong to a class of highly oxidized tetracyclic triterpenoids. Recent studies suggest that the use of Cucurbitacin could repress cancer cell progression. However, the biological effect of Cucurbitacin-B in neuroblastoma cells remains unexplored.

MATERIALS AND METHODS

MTT and BrdU (bromodeoxyuridine) incorporation assays were used to determine the anti-proliferation roles of Cucurbitacin-B. Real-time PCR and Western blot assays were used to detect the expression of cell cycle regulators. Small interfering RNAs (siRNAs) were used to silence the expression of PTEN (phosphatase and tensin homolog gene).

RESULTS

We found that Cucurbitacin-B inhibited growth and modulated expression of cell-cycle regulators in SHSY5Y cells. At the molecular level, we found that Cucurbitacin-B inhibited AKT signaling activation through up-regulation of PTEN. Indeed, PTEN deficiency using siRNA oligos attenuated the anti-proliferative roles of Cucurbitacin-B.

CONCLUSIONS

These results provide evidence for a mechanism that may contribute to the antineoplastic effects of Cucurbitacin-B in neuroblastoma.

A histometric comparison of smooth and rough titanium implants in human low-density jawbone

The aim of this investigation was to conduct a comparative histometric analysis of bone-implant interface between a rough titanium surface and smooth implants in low-density human jawbone after 3, 6, and 12 months of submerged, undisturbed healing. Six adult volunteer patients undergoing standard implant placement were enrolled in this project. Each patient received 1 smooth and 1 rough implant. After 3, 6, and 12 months, the implants were harvested for histometric analysis. The values of bone-implant contact were the following: 3 months smooth 6.2%, 3 months rough 58.9%, 6 months smooth 3.55%, 6 months rough 72.9%, 12 months smooth 6.7%, and 12 months rough 76.75%. The results showed that in low-density bone the rough surface dramatically enhanced the amount of bone-to-implant contact. Because of the small number of implants examined, definite conclusions cannot be drawn, even though the statistical analysis showed significant differences between the smooth and rough groups (P = .0129; F = 76.065). Nevertheless, a trend was evident in these observations: while a rough implant surface may enhance the rate of osseointegration, it is not able to significantly change the bone density, and an implant placed low-density bone is at a higher risk of failure when occlusal loading begins.

[The efficacy of p16, p53 and p21 genes on the proliferation of lung cancer cells in vitro]

OBJECTIVE

Whether the p16, p21 and p53 genes inhibit the proliferation of lung cancer cells after transfecting the genes alone or jointly was examined.

METHODS

The p16, p21 and p53 genes mediated by Stearylamine/DOPE (SA liposome) were introduced alone and jointly into the non-small cell lung cancer (NSCLC) cell line A549 and small cell lung cancer (SCLC) SH77. The effect of the genes on the growth of the cells was detected by MTT method at day 1, 3, 5 after gene transfection.

RESULTS

The p16, p53 and p21 genes alone mediated by SA liposome can inhibit obviously the growth of NSCLC cell line A549 cells, while the genes were slightly effective on SCLC cell line SH77 cells at day 1, 3, 5 after transfecting the genes. But co-transfecting p16 and p21 or p16 and p53 can enhance the inhibiting effect on both A549 and SH77 cells significantly.

CONCLUSIONS

The tumor suppressor genes p16, p53 genes and CDK inhibitor p21 gene may be candidate for gene replacement therapy of NSCLC. Co-transfecting p16 gene and p53 gene may be a better choice.

Bone classification: clinical-histomorphometric comparison

This study was aimed to correlate the hand clinical assessment of the bone quality to the histologic structure quantified by histomorphometric evaluation of bone density. Small bone biopsies were harvested in 56 patients during oral implant surgery, and were utilized for histomorphometric evaluation. The bone scoring was recorded during drilling of the implant bed, based on the hand-felt perception of the drilling resistance. The bone biopsies were then processed to obtain thin ground sections. The results of histomorphometric analysis were expressed as percentage of bony trabeculae over the total biopsy area, and the Spearman's rank correlation test, was applied to calculate the statistical differences of the clinically assessed classes of bone density and linear regression was calculated. Samples from the D1 showed a mean histomorphometric density of 76.54% +/- 16.19. Samples from D2 showed a mean value of 66.78% +/- 15.82. D3 specimens had a mean histomorphometric density scoring 59.61% +/- 19.55%. D4 samples had a mean value of 28.28% +/- 12.02. The interclass correlation analysis of the variance, showed that the clinically assessed classes D1 (P = 0.01) and D4 (P = 0.0006) were significantly different from the population. On the other hand, the classes D2 (P = 0.6) and D3 (P = 0.4) were not significantly different. This study demonstrated that hand feeling allows to distinguish, with statistically significant confidence, D1 and D4 bone, but failed to distinguish between the intermediate classes of bone quality.

Evaluation of linear polyethyleneimine/nitric oxide adduct on wound repair: therapy versus toxicity

A full-thickness wound model was used to evaluate the effects of a topically applied polyethyleneimine-based nitric oxide donor on wound repair in aged rats. Polymer applications were applied over a 10-day period on days 0, 2, 4, 6, and 8 comparing treatment (linear polyethyleneimine-nitric oxide) and control groups (linear polyethyleneimine). Urinary nitrate excretion was quantified as a measure of nitric oxide released. The nitric oxide released from the linear polyethyleneimine-nitric oxide group was significant compared with controls (p </= 0.001), with a maximal nitrate level of 40 micromol on day 1 and an average sustained delivery of 34 micromol/day for the remainder of the study. Wound closure was examined using a computer-based video-imaging analysis system. The wounds of both the linear polyethyleneimine- nitric oxide treatment and linear polyethyleneimine control groups exhibited minimal wound closure; however, the wound closure of the treatment group was significant as compared with the control group (p </= 0.05). A phosphate- buffered saline solution-wounded control was performed that showed cleaner and faster healing wounds, similar to normal healing, than either of the polymer application groups. The histological data showed very little wound healing, on a cellular level, implicating the linear polyethyleneimine-nitric oxide as well as the carrier compound as contributing to the adverse tissue reactions that occurred in the wound bed. Thus, we report the toxic effects of a polyethyleneimine-based compound, as well as the toxic effects of sustained delivery of excess levels of nitric oxide on the wound- repair process. Our findings suggest that there exists indeterminate parameters between therapy and toxicity of nitric oxide delivery to wounds.

[Investigation on computative spectrophotometry employed in the assay of peaonol in cortex moutan]

OBJECTIVE

To investigate the easibility of employed computative spectrophotometry in the assay of traditional Chinese medicines.

METHOD

Make contents of peaonol in 10 samples of Cortex Moutan were determined by three-wavelength spectrophotometry and dual wavelength K-ratio spectrophotometry, and then compared with the method in Chinese Pharmacopeia.

RESULT

The differences of the UV spectrum of different lots of samples bring about relative error. sometimes up to 10%-30% for computative spectrophotometry.

CONCLUSION

Computative spectrophotometry should be used carefully in assaying traditional Chinese medicines.

The bone growing chamber: a new model to investigate spontaneous and guided bone regeneration of artificial defects in the human jawbone

Spontaneous bone repair and regeneration of jawbone defects have been insufficiently studied in the dental literature. The present study analyzes a new human model designed to evaluate the basis for spontaneous bone regeneration in human jawbones. Hollow titanium cylinders, termed "bone growing chambers," were prepared with commercially pure titanium. Ten volunteers undergoing routine implant surgery were enlisted. A properly calibrated drill was used to prepare the bone-growing-chamber bed. The bone growing chamber was inserted inside the bone defect, and care was taken to submerge the cylinder at the level of the bone crest. After an adequate healing period, the bone growing chambers were retrieved with a small quantity of peripheral bone using a calibrated trephine bur. The retrieved specimens were processed to obtain thin undecalcified ground sections. The stable bone growing chambers showed bone tissue inside the growing space. The maturity of the regenerated bone was related to the time of removal. The bone growing chamber provides a well-defined space that is easy to prepare and to retrieve; its dimensions are always identical and it allows quantitative measurements of bone regeneration inside the chamber space.

[Caries susceptibility and caries resistance in a sample of 8140 military conscripts. The clinico-epidemiological considerations]

An epidemiological study on the prevalence of dental caries and resistance in a group of 8,140 called-up soldiers. Possible etiopathogenetic factors or factors which might determine the gradual deterioration of oral health were also analysed.