ß-Galactosidase-guided self-assembled 68Ga nanofibers probe for micro-PET tumor imaging.

ß-galactosidase (ß-gal) has high activity in various malignancies, which is suitable for targeted positron emission tomography (PET) imaging. Meanwhile, ß-gal can successfully guide the formation of nanofibers, which enhances the intensity of imaging and extends the imaging time. Herein, we designed a ß-galactosidase-guided self-assembled PET imaging probe [68Ga]Nap-NOTA-1Gal. We envisage that ß-gal could recognize and cleave the target site, bringing about self-assembling to form nanofibers, thereby enhancing the PET imaging effect. The targeting specificity of [68Ga]Nap-NOTA-1Gal for detecting ß-gal activity was examined using the control probe [68Ga]Nap-NOTA-1. Micro-PET imaging showed that tumor regions of [68Ga]Nap-NOTA-1Gal were visible after injection. And the tumor uptake of [68Ga]Nap-NOTA-1Gal was higher than [68Ga]Nap-NOTA-1 at all-time points. Our results demonstrated that the [68Ga]Nap-NOTA-1Gal can be used for the purpose of a new promising PET probe for helping diagnose cancer with high levels of ß-gal activity.

ß-Galactosidase-Activated and Red Light-Induced RNA Modification Strategy for Prolonged NIR Fluorescence/PET Bimodality Imaging.

Improving the retention of small-molecule-based therapeutic agents in tumors is crucial to achieve precise diagnosis and effective therapy of cancer. Herein, we propose a ß-galactosidase (ß-Gal)-activated and red light-induced RNA modification (GALIRM) strategy for prolonged tumor imaging. A ß-Gal-activatable near-infrared (NIR) fluorescence (FL) and positron emission tomography (PET) bimodal probe 68Ga-NOTA-FCG consists of a triaaza triacetic acid chelator NOTA for 68Ga-labeling, a ß-Gal-activated photosensitizer CyGal, and a singlet oxygen (1O2)-susceptible furan group for RNA modification. Studies have demonstrated that the probe emits an activated NIR FL signal upon cleavage by endogenous ß-Gal overexpressed in the lysosomes, which is combined with the PET imaging signal of 68Ga allowing for highly sensitive imaging of ovarian cancer. Moreover, the capability of 68Ga-NOTA-FCG generating 1O2 under 690 nm illumination could be simultaneously unlocked, which can trigger the covalent cross-linking between furan and nucleotides of cytoplasmic RNAs. The formation of the probe-RNA conjugate can effectively prevent exocytosis and prolong retention of the probe in tumors. We thus believe that this GALIRM strategy may provide entirely new insights into long-term tumor imaging and efficient tumor treatment.

The Efficacy of Magnesium Sulfate (MgSO4) Wet Dressing in Reducing Eyelid Swelling and Bruising after Blepharoplasty: A Randomized, Controlled, and Observer-Blinded Assessment Study.

The purpose of this study was to evaluate the effects of wet dressing with 50% magnesium sulfate (MgSO4) solution on decreasing eyelid swelling and bruising after blepharoplasty. Fifty-eight patients (23 male and 35 female) who underwent bilateral blepharoplasty were enrolled in our randomized clinical trial. One side of the periorbital area (upper and lower eyelids) per patient received a wet dressing with 50% MgSO4 solution randomly, and the other side was cooled with an ice pack from the first postoperative day for two consecutive days (30 minutes per time and twice a day). The eyelid edema and ecchymosis were evaluated and classified using respective graded scales. Degrees of eyelid edema were similar after surgery in both groups (p > 0.05) and were significantly decreased with time. Compared with the cooled ones, less swelling was observed in the eyelids treated by MgSO4 wet compress on postoperative day 5 (p < 0.01). Both the incidence and area of ecchymosis were lower in the MgSO4 group than those in the cooling group (p < 0.01 and p < 0.05, respectively). Moreover, the majority of patients (39/58, 67.2%) indicated a preference for MgSO4 wet dressing over ice cooling. MgSO4 wet dressing can be conveniently applied to alleviate eyelid swelling and reduce recovery time after blepharoplasty.

Synthesis and preliminary biological evaluation of a novel 99mTc-labeled small molecule for PD-L1 imaging.

In recent years, PD-1/PD-L1 checkpoint blockade immunotherapy with remarkable efficacy has set off a heat wave. The expression level of PD-L1, which plays a predictive role in anti-PD-1/PD-L1 therapy, could be quantified by noninvasive imaging with radiotracers. Herein, we introduced the synthesis and preliminary biological evaluation of a novel 99mTc-labeled small molecule radiotracer [99mTc]G3C-CBM for PD-L1 imaging. [99mTc]G3C-CBM was achieved with high radiochemical purity (>96 %) and remained good stability in PBS and FBS. In competitive combination experiment, [99mTc]G3C-CBM was displaced by increasing concentrations of unlabeled G3C-CBM, resulting in an IC50 value of 41.25±2.23 nM for G3C-CBM. The uptake of [99mTc]G3C-CBM in A375-hPD-L1 cells (17.51±2.08 %) was approximately 6.47 folds of that in A375 cells (2.71±0.36 %) after co-incubation for 2 h. The biodistribution results showed that the radioactivity uptake in A375-hPD-L1 tumor reached the maximum (0.35±0.01 %ID/g) at 2 h post injection, and the optimum tumor/muscle ratio of 2.94±0.29 occurred at the same time. In addition, [99mTc]G3C-CBM was quickly cleared from the blood with a clearance half-life of just 119.25 min. These results indicate that [99mTc]G3C-CBM is a potential SPECT PD-L1 imaging agent and is worthy of further study.

Prediction of Esophageal Stricture after Endoscopic Submucosal Dissection in Patients with Early Esophageal Cancer.

BACKGROUND: Endoscopic submucosal dissection (ESD) treatment of early esophageal cancer is effective and safe. It is currently the first-line treatment for early esophageal cancer. However, a common side effect is the development of esophageal strictures after ESD. This study was designed to identify the risk factors for esophageal stricture development and to predict its occurrence after ESD. METHODS: In this retrospective study, 150 consecutive patients with early esophageal cancer treated with ESD at Daping Hospital, Chongqing, were enrolled between January 2016 and December 2020. Data on patient demographics, esophageal tumor characteristics, procedure-related factors, and postoperative situations were collected. We identified independent risk factors of esophageal stricture formation using univariate analysis and multivariate logistic regression. The predictive probability was obtained after multivariate logistic analysis. In addition, patients were divided into six groups based on these risk factors and the rate of esophageal stricture in each group was analyzed. RESULTS: The postoperative esophageal stricture rate was 14% (21/150). Tumor location (OR = 5.655, 95% CI: 1.245-25.691, P = 0.025) and circumferential resection range (OR = 16.113, 95% CI: 4.294-60.466, P < 0.001) are independent risk factors for the development of esophageal strictures. According to predictive probability analysis and the rates of stricture in six groups, we developed a possible flow chart to predict stricture formation. CONCLUSIONS: Tumor location and circumferential resection range are reliable risk factors to predict the occurrence of esophageal strictures. Our prediction flow chart suggests that tumors with a circumferential resection range of 1/2-3/4 and located above the upper thoracic segment or a circumferential resection range of > 3/4 have a high risk of postoperative stricture. Thus, timely and effective preventive measures should be taken in these patients following ESD.

Recent advances in the synthesis of 2,3-fused quinazolinones.

As one of the most important structural units in pharmaceuticals and medicinal chemistry, quinazolinone and its derivatives exhibit a wide range of biological and pharmacological activities, including anti-inflammatory, antitubercular, antiviral, and anticancer activities, etc. In particular, 2,3-fused quinazolinones have attracted much attention because the rings fused to the 2,3-positions of quinazolinones improve their rigidity and planarity. Their synthetic strategies have made great advances in recent years. Therefore, this review focuses on novel strategies for the synthesis of 2,3-fused quinazolinone derivatives from 2017 to 2022, such as the difunctionalization of alkenes, the ring-opening of easily available small rings, dehydrogenative cross-coupling reactions, transition-metal catalyzed cyclizations, cycloadditions, and other cascade reactions.

Conditioned medium from the bone marrow mesenchymal stem cells modulates immune response via signal transduction and activator of transcription 6 signaling pathway in an allergic rhinitis mouse model.

BACKGROUND: Allergic rhinitis (AR) is a common immune disease of the nasal mucosa characterized with immunoglobulin E (IgE)-mediated allergic inflammation after exposure to allergens in susceptible population. Previous reports have demonstrated that the bone marrow mesenchymal stem cells (BMSCs) could reduce allergic inflammation. However, there is little knowledge about whether the culture supernatant of BMSCs (conditioned medium, CM) has similar anti- inflammatory potential in treating AR. OBJECTIVE: The study aimed to evaluate the immunoregulatory effects of conditioned medium derived from BMSCs (BMSC-CM) on allergic inflammation in an AR mouse model. MATERIAL AND METHODS: The AR murine model was induced by repeated sensitization and challenges with ovalbumin (OVA). Subsequently the allergic symptoms of AR mice, cytokine levels, the histopathological features of the nasal mucosa and T helper 1 (Th1) : T helper 2 (Th2) cells ratio were evaluated. RESULTS: Treatment with BMSC-CM was found as effective as BMSCs in reducing allergic symptoms and inhibiting eosinophilic infiltration in the nasal mucosa. After BMSC-CM or BMSCs administration, the OVA-specific IgE and interleukin 4 levels in serum decreased and interferon gamma level increased compared with AR mice treated with uncultured fresh medium. Flow cytometry analysis revealed a decrease in Th1:Th2 cells ratio after OVA-sensitization and the ratio was reversed by BMSC-CM and BMSCs treatments. Furthermore, the data revealed that BMSC-CM suppressed the production of signal transduction and activator of transcription 6 (STAT6) at messenger RNA and protein levels in the nasal mucosa. CONCLUSION: BMSC-CM could ameliorate allergic inflammation and regulate the balance of Th cells, and the underlying mechanism was closely related to STAT6 signaling pathway. The immunoregulatory effects of BMSCs could be achieved through paracrine function, and nasal dripping of BMSC-CM might be a novel approach for the treatment of AR.

Intracellular Synthesis of Hybrid Gallium-68 Nanoparticle Enhances MicroPET Tumor Imaging.

Positron-emission tomography (PET) imaging enables cancer diagnosis at an early stage and to determine its pathological degree. However, tumor uptake efficiency of traditional PET radiotracers is usually low. Herein, we rationally designed a precursor CBT-NODA, the cold analogue CBT-NODA-Ga, and its corresponding radiotracer CBT-NODA-68Ga. Using these three compounds, we verified that coinjection of CBT-NODA-68Ga with CBT-NODA or CBT-NODA-Ga could lead to the synthesis of hybrid gallium-68 nanoparticles in furin-overexpressing cancer cells and enhance microPET tumor imaging in mice. In vivo experiments showed that coinjection of CBT-NODA-68Ga with CBT-NODA-Ga had the most prolonged retention of the radiotracer in blood, the highest radioactivity in tumor regions, and the most enhanced microPET tumor imaging in mice. We anticipate that, by combining the coinjection strategy with our CBT-Cys click condensation reaction, more radiotracers are developed for microPET imaging of more tumors in clinical settings in the future.

A novel fluorescent aptasensor based on exonuclease-assisted triple recycling amplification for sensitive and label-free detection of aflatoxin B1.

Aflatoxins are the most toxic type of mycotoxins, which may cause serious carcinogenesis, teratogenesis, and mutagenesis to humans and animals. In this work, we demonstrate a novel label-free fluorescent aptasensor based on exonuclease-assisted triple recycling amplification for the sensitive detection of aflatoxin B1 (AFB1). With the close cooperation of T7 exonuclease and three elaborately designed hairpin probes, the target AFB1 can perform three consecutive cycles of amplification reactions. In this process, each hairpin probe is fully utilized, and the target AFB1, the secondary target and the tertiary target are recycled, thereby achieving a high amplification. Interestingly and importantly, the secondary and tertiary targets generated by amplification are also excellent DNA template sequences for silver nanoclusters (AgNCs). In the presence of NaBH4 and AgNO3, a great number of DNA-AgNCs are synthesized, thereby producing a strong fluorescent signal. Under optimal conditions, the developed aptasensor exhibited high sensitivity to AFB1 with a low detection limit of 0.19 pg mL-1 and a wide dynamic range of 1 × 10-6-1 µg mL-1. In addition, the aptasensor also performed well in the determination of AFB1 in real samples.

Furin-Guided Intracellular 68Ga Nanoparticle Formation Enhancing Tumor MicroPET Imaging.

Positron-emission tomography (PET) is routinely used in the clinic for tumor imaging with ultrahigh sensitivity, but tumor-targeted PET imaging probes are quite few. In this work, we rationally designed a furin-responsive radiotracer Acetyl-Arg-Val-Arg-Arg-Cys(StBu)-Lys(DOTA-68Ga)-CBT (CBT-68Ga) and demonstrated that coinjection of the radiotracer with its cold analogue CBT-Ga instructed the formation of 68Ga nanoparticles in furin-overexpressing MDA-MB-468 cancer cells, which significantly enhanced microPET imaging of the tumor in vivo. In vitro results showed that CBT-Ga subjected to furin-initiated CBT-Cys condensation reaction and self-assembly to form the nanoparticles CBT-Ga-NPs with an average diameter of 258.3 nm. In vivo microPET imaging results indicate that the mice coinjected with CBT-68Ga and CBT-Ga, which warrants 68Ga nanoparticle formation in their MDA-MB-468 tumors, had a tumor/liver ratio 9.1-fold of that of the mice only injected with CBT-68Ga. We envisioned that, by replacing the RVRR substrate of CBT-68Ga with other enzyme-specific ones and using the strategy of intracellular nanoparticle formation, a series of radioactive probes could be developed for more sensitive and precise tumor microPET imaging in the near future.

[Inhibitory effect of polyphyllin â on the proliferation of prostate cancer PC3 cells via ERK1/2/P65/DNMT1 and its molecular mechanism].

OBJECTIVE: To explore the inhibitory effect of polyphyllin Ⅰ (PPⅠ) on the proliferation of castration-resistant prostate cancer PC3 cells and its molecular mechanism. METHODS: We cultured human prostate cancer PC3 cells in vitro and treated them with PPⅠ at the concentrations of 0 (blank group), 0.4, 0.8, 1.2, 1.6, 2.0, and 2.4 µmol/L for 24, 48, and 72 hours, respectively. Then we detected the proliferation of the cells by MTT assay, measured their apoptosis by flow cytometry, and determined the expressions of p-ERK1/2, ERK1/2, NF-κB/p65 and DNMT1 proteins as well as the level of NF-κB/p65 in the cells additionally treated with the ERK1/2 inhibitor SP600125 by Western blot. RESULTS: Compared with the blank control group, the PPⅠ-treated PC3 cells showed a concentration- and time-dependent reduction of the survival rate (1.00 ± 0.00 vs 0.85 ± 0.05, P < 0.01) at 0.4 µmol/L after 48 hours of intervention, concentration-dependent early apoptosis at 0.8 µmol/L (4.83 ± 0.95 vs 13.83 ± 2.97, P < 0.01), time-dependent increase of the expressions of p-ERK1/2 (1.00 ± 0.00 vs 1.73 ± 0.17, P < 0.01) and ERK1/2 (1.00 ± 0.00 vs 1.36 ± 0.12, P < 0.01) at 2 hours, and concentration-dependent decrease of the expressions of NF-κB/p65 and DNMT1 at 1.2 µmol/L (1.00 ± 0.00 vs 0.78 ± 0.10 and 0.63 ± 0.06, P < 0.01) and 1.6 µmol/L (1.00 ± 0.00 vs 0.67 ± 0.11 and 0.52 ± 0.09, P<0.01). Inhibition of ERK1/2 phosphorylation with PD98059 markedly reversed PPⅠ-induced decrease of the NF-κB/p65 expression as compared with that in the PPⅠ group (0.86 ± 0.18 vs 0.43 ± 0.09, P < 0.05). CONCLUSIONS: PPⅠ induces the early apoptosis and suppresses the proliferation of PC3 cells, probably by activating the ERK1/2 pathway and inhibiting the expressions of the NF-κB/p65 and DNMT1 proteins.

A Cohort Study of Incidences and Risk Factors for Thromboembolic Events in Patients with Idiopathic Membranous Nephropathy.

Objective The aims of this study were to assess incidences and characteristics of arterial thromboembolic events (ATEs) and venous thromboembolic events (VTEs) in Chinese patients with idiopathic membranous nephropathy (IMN), and to identify the predisposing risk factors of them.Methods A total of 766 consecutive Chinese patients with IMN were enrolled in this retrospective cohort study. The cumulative incidences of newly diagnosed ATEs and VTEs were calculated using Kaplan-Meier methods. Univariable risk prediction model analysis followed by multivariable survival analysis was used to evaluate the potential risk factors of ATE and VTE.Results At 0.5, 1, 2, 3, and 5 years after biopsy diagnosis of IMN, the cumulative incidence of newly diagnosed ATEs were 4.3%, 5.7%, 6.3%, 7.1%, and 8.0%, and of newly diagnosed VTEs were 5.9%, 6.8%, 6.9%, 7.0%, and 7.2%, respectively. In 78 ATEs events (71 patients), cardiovascular diseases, thrombotic ischemic stroke (IS) and peripheral artery disease accounted for 50%, 45% and 5% respectively; in 60 VTEs events(53 patients), the deep vein thrombosis, renal vein thrombosis and pulmonary embolism accounted for 60%, 13% and 27% respectively. At the time of event, 42.1% patients with ATEs and 81.5% patients with VTEs were at nephrotic syndrome(NS) status (χ 2=18.1, P<0.001). Severe proteinuria, aging, smoking, hypertension and prior ATE history were associated with ATEs. Aging was demonstrated as the independent risk factor for ATEs (P=0.001), and hypoalbuminemia was the dominant independent risk factor for VTEs (P=0.03). Conclusions Patients with IMN have increased incidences of ATEs and VTEs, and most of events occurred within the first 6 months of the disease. IS was very common in ATEs in our cohort. Severe proteinuria and classic risk factors for atherosclerosis were associated with onset of ATEs. Hypoalbuminemia independently predicted VTEs. Risks of both ATEs and VTEs were particularly high in the status of NS, particularly VTEs.

Therapy of Rituximab in Idiopathic Membranous Nephropathy with Nephrotic Syndrome: A Systematic Review and Meta-analysis.

Objective To investigate the efficacy and safety of rituximab (RTX) in the treatment of idiopathic membranous nephropathy (IMN) with nephrotic syndrome with a systematic review and meta-analysis. Methods PubMed, Embase, Cochrane Library and Clinical Trials (December 2016) were searched to identify researches investigating the treatment of RTX in adult patients with biopsy-proven IMN. Complete remission (CR) or partial remission was regarded as effective therapy, and the cumulated remission rate was calculated. Result Seven studies involved 120 patients (73% were men) were included in our systematic review and meta-analysis. All were prospective observation cohort studies or matched-cohort studies, mainly came from two medical centers, and one study was multi-centric (four nephrology units in northern Italy). The creatinine clearance was more than 20 ml/(min·1.73 m2) and persistent proteinuria higher than 3.5 g/d for at least 6 months. All patients received treatment previously [44 (36.7%) had immunosuppressive treatment]. In 12- and 24-month, 56% (95%CI, 0.47-0.65) and 68% (95%CI, 0.41-0.87) patients could reach remission, while 15% (95%CI, 0.09-0.23) and 20% (95%CI, 0.12-0.32) patients could reach CR. The reduction in proteinuria was gradual and obvious, paralleled with upward trend of serum albumin level and decreasing serum cholesterol level. Renal functions were stable. Relapses happened in 24 months were around 8%. RTX related adverse events were mild and were mostly infusion-related reactions. Conclusions RTX treatment in IMN was efficient, well tolerated and safe. More than 60% patients can reach partial remission or CR in 24 months, and relapse is rare. Adverse events of RTX are mostly infusion-related reactions and generally mild.

The Neglected Significance of Glomerular Density as a 5-year Progression Indicator for IgA Nephropathy△.

Objective To investigate whether glomerular density (GD) could be an independent prognostic factor for patients of IgA nephropathy with estimated glomerular filtration rate (eGFR) of 30 to 60 ml/min per 1.73 m2, or for patients with time-average proteinuria < 0.5 g/d. Methods A total of 173 patients with biopsy-confirmed IgA nephropathy diagnosed from January 2000 to December 2010 were included. All of these patients were followed up for more than 5 years. The endpoint was a > 30% of decline in eGFR from baseline after 5-year follow-up. The optimal cut-off value of GD was calculated by ROC curve. Kaplan-Meier method and Cox regression analysis was used for survival analysis. Results A 30% of decline in eGFR occurred in 14.5% of all patients. The optimal diagnostic cut-off value of GD was 1.99/mm2 (AUC = 0.90, sensitivity = 84.0%, specificity = 81.8%) determined by ROC curve. The low GD group (GD < 1.99 per mm2) experienced a significant increase in renal endpoint for patients with eGFR of 30 to 60 ml/min per 1.73 m2 (six patients in lower GD group, while one patient in the other group). For patients with time-average proteinuria < 0.5 g/d, the lower GD group showed a higher eGFR decline from baseline (4.5±16.7 ml/min per 1.73 m2 vs. -8.1±21.4 ml/min per 1.73 m2, P = 0.038); two patients in this group reached the endpoint, while no patients in the higher GD group did. Conclusion GD could be an independent prognostic factor for patients of IgA nephropathy with eGFR at 30 to 60 ml/min per 1.73 m2 of body surface, particularly for those with time-averaged amount of urine protein less than 0.5 g per day.

Anodic Oxidation in Aluminum Electrode by Using Hydrated Amorphous Aluminum Oxide Film as Solid Electrolyte under High Electric Field.

Dense and nonporous amorphous aluminum oxide (AmAO) film was deposited onto platinized silicon substrate by sol-gel and spin coating technology. The evaporated aluminum film was deposited onto the AmAO film as top electrode. The hydrated AmAO film was utilized as a solid electrolyte for anodic oxidation of the aluminum electrode (Al) film under high electric field. The hydrated AmAO film was a high efficiency electrolyte, where a 45 nm thick Al film was anodized completely on a 210 nm thick hydrated AmAO film. The current-voltage (I-V) characteristics and breakdown phenomena of a dry and hydrated 210 nm thick AmAO film with a 150 nm thick Al electrode pad were studied in this work. Breakdown voltage of the dry and hydrated 210 nm thick AmAO film were 85 ± 3 V (405 ± 14 MV m(-1)) and 160 ± 5 V (762 ± 24 MV m(-1)), respectively. The breakdown voltage of the hydrated AmAO film increased about twice, owing to the self-healing behavior (anodic oxidation reaction). As an intuitive phenomenon of the self-healing behavior, priority anodic oxidation phenomena was observed in a 210 nm thick hydrated AmAO film with a 65 nm thick Al electrode pad. The results suggested that self-healing behavior (anodic oxidation reaction) was occurring nearby the defect regions of the films during I-V test. It was an effective electrical self-healing method, which would be able to extend to many other simple and complex oxide dielectrics and various composite structures.

Enzyme-Controlled Intracellular Self-Assembly of (18)F Nanoparticles for Enhanced MicroPET Imaging of Tumor.

Herein, we report the development of a new "smart" radioactive probe (i.e., 1) which can undergo furin-controlled condensation and self-assembly of radioactive nanoparticles (i.e., 1-NPs) in tumor cells and its application for enhanced microPET imaging of tumors in nude mice co-injected with its cold analog (i.e., 1-Cold). Furin-controlled condensation of 1-Cold and self-assembly of its nanoparticles (i.e., 1-Cold-NPs) in vitro were validated and characterized with HPLC, mass spectra, SEM, and TEM analyses. Cell uptake studies showed that both 1 and 1-Cold have good cell permeability. TEM images of 1-Cold-treated MDA-MB-468 cells directly uncovered that the intracellular 1-Cold-NPs were at/near the location of furin (i.e., Golgi bodies). MTT results indicated that 50 µM 1-Cold did not impose cytotoxicity to MDA-MB-468 cells up to 12 hours. MicroPET imaging of MDA-MB-468 tumor-bearing mice indicated that mice co-injected with 1 and 1-Cold showed higher uptake and longer attenuation of the radioactivity in tumors than those mice only injected with same dosage of 1. Tumor uptake ratios of 1 between these two groups of mice reached the maximum of 8.2 folds at 240 min post injection. Biodistribution study indicated that the uptake ratios of 1 in kidneys between these two groups continuously increased and reached 81.9 folds at 240 min post injection, suggesting the formation of radioactive NPs (i.e., 1-NPs) in MDA-MB-468 tumors of mice co-injected with 1 and 1-Cold. And the nanoparticles were slowly digested and secreted from the tumors, accumulating in the kidneys. Our ''smart'' probe (i.e., 1), together with the strategy of co-injection, might help researchers trace the biomarkers of interest within a longer time window.

[Effects of iron on the algae growth and microcystin synthesis: a review].

Iron, as one of the essential mineral elements for algae growth, plays an extremely important role in the physiological processes such as plant photosynthesis, respiration, nitrogen fixation, protein and nucleic acid synthesis. In view of the fact that iron in different forms could be absorbed and utilized by algae, the existing forms and circulation approaches in the aquatic environment, the absorption mechanism by algae, and the effects on algae growth and microcystin synthesis were reviewed in this paper. The relevant microcystin synthesis genes and their expression under iron restricted conditions were summarized, and the research directions for harmful algal blooms regulation and control by ferritin genes were suggested. It was hoped to provide the reference for eutrophication remediation technology.

[Polarized microscopic observation of the collagen change in bone healing during bone lengthening].

OBJECTIVE: To investigate the feature and regularity of the collagen change in bone healing during bone lengthening. METHODS: Bone lengthening model was made in the middle segment of the rabbit tibia. Five days after the model was established, the bone was lengthened 1.5 mm per day for 14 days. The rabbits were put to death after elongation, 7, 14, 21, 30, 40, 50, 60 and 70 days after elongation. The distracted area of the bone was imbedded with paraffin. After being stained by the picric acid-sirius red staining, the slice was observed under polarized microscope. RESULTS: The features of the collagen change in the distracted bone were as follows: (1) In the fibrous tissue of the distracted area during lengthening period and the early stage after lengthening, there was not only collagen III but also much collagen I. (2) Collagen I , II and III were observed in the cartilage. (3) Collagen I, II and III were also observed in the pseudo-growth plate. (4) Collagen I took the dominance during lengthening period and the late stage after lengthening. CONCLUSION: New bone formation in bone lengthening is under the distracted force, so the collagen changes have different features compared with that in fracture healing. Collagen I, II and III can be identified by picric acid-sirius red staining and polarized microscope, so a new method for studying the collagen typing in bone repairing is provided.