Isolated non-immune mediated second-degree atrioventricular block in fetus: natural history and predictive factors for spontaneous recovery

OBJECTIVES

To uncover the clinical course of fetal isolated non-immune mediated second-degree AVB and determine the factors associated with the spontaneous recovery for fetal non-immune second-degree atrioventricular block (AVB).

METHODS

A total of 20 fetuses with isolated, non-immune mediated second-degree AVB were prospectively recruited between 2014 and 2022. These fetuses were divided into the spontaneous recovery group (n=12) and the non-spontaneous recovery group (n=8). Maternal and fetal basic characteristics, intrauterine and postnatal outcomes were compared between groups.

RESULTS

Twelve fetuses restored 1:1 atrioventricular conduction in utero and did not recur during the postnatal follow-up period. The residual eight fetuses maintained as second-degree AVB and six of them were aborted due to parental request in utero. Of the two live children with second-degree AVB, one of them progressed to complete AVB at the latest follow up at the age of 34 months, but without any symptoms, heart enlargement or dysfunction. The residual one progressed to complete AVB and was finally diagnosed with type 2 long-QT syndrome. Fetuses in the spontaneous recovery group presented with earlier gestational age at diagnosis (20.0[17.0-26.0] vs. 24.5[18.0-35.0] weeks, p=0.004) and higher atrial rate (147[130-160] vs 138.00[125.00-149.00] bpm, p=0.006) in comparison with the non-spontaneous recovery group. A cut-off value of 22.5 weeks of gestational age and 144 bpm of atrial rate at diagnosis could predict the failure of spontaneous recovery, with sensitivities of 87.5%, 75%, and specificities of 92.0%, 87.5%, respectively.

CONCLUSIONS

The outcome of fetal non-immune second-degree AVB was favorable. Earlier gestational age at diagnosis and higher atrial rate were related to spontaneous reversion for isolated non-immune-mediated second-degree AVB. However, prenatal gene test should be performed for those with persistent AVB to exclude the heritable disorders including LQTS. These findings may provide important references for clinical management and prenatal counseling. This article is protected by copyright. All rights reserved.

Soil microbial diversity under different types of interference in birch secondary forest in the Greater Khingan Mountains in China

Introduction

Soil microorganisms are an important component of soil ecosystems with an indispensable role in forest ecosystems. We analyzed the soil microbial diversity in birch secondary forest formed by natural restoration or artificial reconstruction after interference by burning, clear cutting, and gradient cutting, and the Betula platyphylla Suk undisturbed forest in the Greater Khingan Mountains in China.

Methods

Illumina high-throughput sequencing technology was used to analyze the characteristics of the soil microbial community during the restoration process of birch secondary forest caused by the different types of interference. The relationships between bacteria and fungi were analyzed. The gene functions of the soil bacterial community and the ecological functions of soil fungi were predicted using PICRUSt and FunGuild, respectively.

Results

At the phylum level, the species and quantity of bacteria were more abundant than that of fungi. At the genus level, no obvious differences in the abundance of bacteria were observed; there were obvious differences in the abundance of fungi. Among the eight sample plots, the artificial larch forest belt had the highest bacterial and fungal alpha diversity, which was slightly higher than undisturbed forest, while the other sample plots were significantly lower. Gradual cutting pure birch forest bacteria and fungi had the highest beta diversity, and artificial larch forest belt bacteria and heavy burn sample plot fungi had the lowest beta diversity. Samples from the cutting and burning sample plots were significantly different from the undisturbed forest at the phylum level of Acidobacteriae, Acidimicrobiia, Mortierellomycetes and Sordariomycetes. We found statistical differences in biomarkers between bacterial and fungal communities in undisturbed forest and artificial larch forest belt and burn sample plots. PICRUSt prediction and FunGuild prediction showed that soil bacterial and fungal communities were rich in gene and ecological functions, respectively. In the microbial network, the stability or anti-interference performance of the fungal community was higher than that of bacteria.

Conclusion

Our data reveal the characteristics of the soil microbial community during the restoration process of Betula platyphylla Suk secondary forest under different types of disturbance, which is of great significance for understanding the role of soil microorganisms in the forest ecological cycle.

Highly efficient generation of narrowband terahertz radiation driven by a two-spectral-line laser in PPLN

We demonstrate record ∼0.9% efficiencies for optical conversion to narrowband (<1% relative bandwidth) terahertz (THz) radiation by strongly cascaded difference frequency generation. These results are achieved using a novel, to the best of our knowledge, laser source, customized for high efficiencies, with two narrow spectral lines of variable separation and pulse duration (≥250 ps). THz radiation generation in 5% MgO-doped periodically poled lithium niobate (PPLN) crystals of varying poling period was explored at cryogenic and room temperature operation as well as with different crystal lengths. This work addresses an increasing demand for high-field THz radiation pulses which has, up to now, been largely limited by low optical-to-THz radiation conversion efficiencies.

Stabilization and sensory evaluation of calcium-enriched soymilk prepared using different chelating agents

It is generally acknowledged that calcium lactate (ca-lactate) fortification of soymilk to achieve the equivalent calcium level in cow’s milk (1.2 mg/g) causes instability in soymilk. In order to produce acceptable calcium-enriched soymilk with great stability, three different kinds of chelating agents were added, namely tripotassium citrate (TPC), trisodium citrate (TSC), and sodium hexametaphosphate (SHMP). In this study, the addition of ca-lactate was found to reduce the pH (6.62 to 5.37) and increase the particle diameter (268.66 to 1,222.81 nm) and sedimentation (0.19 to 8.75%) of soymilk. Meanwhile, the addition of TPC and TSC produced calcium-enriched soymilks with smaller particle diameter (295.21-452.22 nm and 297.61-461.80 nm) and lower sedimentation levels (0.25-1.55% and 0.26-1.58%). The pH of calcium-enriched soymilk was also increased when both chelating agents were added. The application of SHMP as a chelating agent was not as effective as TPC and TSC because the particle diameter (527.98-703.40 nm) and sedimentation level were still relatively higher (4.24-5.68%) than the unfortified soymilk. Even though both TPC and TSC showed no significant difference (P>0.05) in stability, the sensory evaluation showed different results. Soymilk with TSC added was saltier and sourer than samples with TPC added. The study recommends the use of TPC as the chelating agent in soymilk enriched with ca-lactate.

Average SAR prediction, validation, and evaluation for a compact MR scanner head-sized RF coil

A recently developed compact 3 T (C3T) MRI scanner with high performance gradients [1, 2] has a dedicated radiofrequency (RF) transmit coil that exposes only the head, neck and a small portion of the upper body region during head-first scanning. Due to the unique coil geometry and patient positioning, the established SAR model used for a conventional whole-body scanner cannot be directly translated to the C3T. Here a specific absorption rate (SAR) estimation and validation framework was developed and used to implement a dedicated and accurate SAR prediction model for the C3T. Two different SAR prediction models for the C3T were defined and evaluated: one based on an anatomically derived exposed mass, and one using a fixed anatomical position located caudally to the RF coil to determine the exposed mass. After coil modeling and virtual human body simulation, the designed SAR prediction model was implemented on the C3T and verified with calorimetry and in vivo scan power monitoring. The fixed-demarcation exposed mass model was selected as appropriate exposed mass region to accurately estimate the SAR deposition in the patient on the C3T.

Five lncRNAs associated with the survival of hepatocellular carcinoma: a comprehensive study based on WGCNA and competing endogenous RNA network

OBJECTIVE

The competing endogenous RNA (ceRNA) presents a comprehensive regulatory network among lncRNAs, miRNAs and mRNA. The ceRNA provides significant information in understanding the pathology of cancer. This study aimed to explore a lncRNA-associated ceRNA network for predicting the overall survival of patients with hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

In this study, RNA-sequencing data of HCC were downloaded from The Cancer Genomes Atlas (TCGA) database. The module-trait relationship was analyzed with Weighted gene co-expression network analysis (WGCNA). The key module associated with tumor was identified, as well as the involved lncRNAs, mRNAs and miRNAs. The preliminary ceRNA network was constructed with Cytoscape. The survival analysis was further performed to screen survival-relevant lncRNAs, mRNAs and miRNAs, and then the survival-associated ceRNA network was reconstructed.

RESULTS

Eventually, 5 lncRNAs, 10 miRNAs, and 25 mRNAs were included in the reconstructed ceRNA network.

CONCLUSIONS

The identified lncRNAs were promising candidate biomarkers in HCC diagnosis and therapeutics. This analysis process was effective to construct ceRNA network. The result will be conductive to explore the significant lncRNAs and regulatory mechanism.

Development of a PET/EPRI combined imaging system for assessing tumor hypoxia

Precise quantitative delineation of tumor hypoxia is essential in radiation therapy treatment planning to improve the treatment efficacy by targeting hypoxic sub-volumes. We developed a combined imaging system of positron emission tomography (PET) and electron para-magnetic resonance imaging (EPRI) of molecular oxygen to investigate the accuracy of PET imaging in assessing tumor hypoxia. The PET/EPRI combined imaging system aims to use EPRI to precisely measure the oxygen partial pressure in tissues. This will evaluate the validity of PET hypoxic tumor imaging by (near) simultaneously acquired EPRI as ground truth. The combined imaging system was constructed by integrating a small animal PET scanner (inner ring diameter 62 mm and axial field of view 25.6 mm) and an EPRI subsystem (field strength 25 mT and resonant frequency 700 MHz). The compatibility between the PET and EPRI subsystems were tested with both phantom and animal imaging. Hypoxic imaging on a tumor mouse model using 18F-fluoromisonidazole radio-tracer was conducted with the developed PET/EPRI system. We report the development and initial imaging results obtained from the PET/EPRI combined imaging system.

MicroRNA-1286 inhibits osteogenic differentiation of mesenchymal stem cells to promote the progression of osteoporosis via regulating FZD4 expression

OBJECTIVE

The aim of this study was to investigate whether microRNA-1286 could inhibit the osteogenic differentiation of human marrow mesenchymal stem cells (hMSCs) by regulating FZD4 expression and promoting the progression of osteoporosis.

PATIENTS AND METHODS

Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was used to detect the expression of microRNA-1286 in the serum of patients with osteoporosis. Meanwhile, microRNA-1286 expression in different stages of osteogenic differentiation of hMSCs was measured by qRT-PCR as well. After overexpression of microRNA-1286 and FZD4 in hMSCs, the mRNA expression levels of microRNA-1286, alkaline phosphatase (ALP), RUNX2 and osteocalcin (OCN) were detected by qRT-PCR. The protein expression levels of RUNX2 and OCN were detected by Western blot. Meanwhile, alkaline phosphatase (ALP) activity and expression in cells were examined using ALP assay kit and ALP staining method, respectively. Cell mineralized nodules were detected through the alizarin red staining test. Bioinformatics method was used to predict the binding site of microRNA-1286 to FZD4. Subsequent luciferase reporter gene assay was performed to verify whether microRNA-1286 could combine with FZD4. After overexpression or knockdown of microRNA-1286, the mRNA and protein expressions of FZD4 were analyzed using qRT-PCR and Western blot assay, respectively. After the simultaneous overexpression of microRNA-1286 and FZD4 in hMSCs, the mRNA expression levels of ALP, RUNX2 and OCN, ALP activity and content, and cell mineralization ability were successively examined.

RESULTS

The expression of microRNA-1286 in the serum of patients with osteoporosis was significantly higher than that of the normal population. Meanwhile, microRNA-1286 expression decreased with the increase of osteogenic differentiation days of hAMSCs. After the overexpression of microRNA-1286, ALP, RUNX2, and OCN levels, ALP activity, RUNX2, and OCN protein levels, as well as mineralized nodule formation were significantly reduced. However, results were reversed when FZD4 was simultaneously up-regulated. Luciferase reporter gene assay results verified that microRNA-1286 could bind to FZD4. After the overexpression of microRNA-1286, the mRNA and protein expressions of FZD4 were found significantly down-regulated. However, results were reversed after knocking down microRNA-1286. Furthermore, the simultaneous overexpression of microRNA-1286 and FZD4 could counteract the inhibitory effect of over-expression of microRNA-1286 on osteogenic differentiation of hMSCs.

CONCLUSIONS

MicroRNA-1286 can regulate FZD4 expression and inhibit osteogenic differentiation of hMSCs, thereby promoting the development of osteoporosis.

Design, evaluation and initial imaging results of a PET insert based on strip-line readout for simultaneous PET/MRI

We present the development of a PET insert system for potential simultaneous PET/MR imaging using a 9.4 T small animal MRI scanner to test our system. The detectors of the system adopt a strip-line based multiplexing readout method for SiPM signals. In this readout, multiple SiPM outputs in a row share a common strip-line. The position information about a hit SiPM is encoded in the propagation time difference of the signals arriving at the two ends of the strip-line. The use of strip-lines allows us to place the data acquisition electronics remotely from the detector module to greatly simplify the design of the detector module and minimize the mutual electromagnetic interference. The prototype is comprised of 14 detector modules, each of which consists of an 8x4 LYSO scintillator array (each LYSO crystal is 3x3x10 mm³) coupled to two units of Hamamatsu MPPC arrays (4x4, 3.2 mm pitch) that are mounted on a strip-line board. On the strip-line board, outputs of the 32 SiPMs are routed to 2 strip-lines so that 16 SiPM signals share a strip-line. The detector modules are installed inside a plastic cylindrical supporting structure with an inner and outer diameter of 60 mm and 115 mm, respectively, to fit inside a Bruker BioSpec 9.4 Tesla MR scanner. The axial field of view of the prototype is 25.4 mm. The strip-lines were extended by using 5-meter cables to a sampling data acquisition (DAQ) board placed outside the magnet. The detectors were not shielded in the interest of investigating how they may affect and be affected by the MRI. Experimental tests were conducted to evaluate detection performance, and phantom and animal imaging were carried out to assess the spatial resolution and the MR compatibility of the PET insert. Initial results are encouraging and demonstrate that the prototype insert PET can potentially be used for PET/MR imaging if appropriate shielding will be implemented for minimizing the mutual interference between the PET and MRI systems.

Diversity and abundance of comammox bacteria in the sediments of an urban lake

AIMS

Although comammox have been discovered in a variety of ecosystems, there are few studies in urban lakes. This paper attempted to confirm whether this ammonia-oxidizing microbe exists in urban lakes and to determine the factors influencing its existence.

METHODS AND RESULTS

This study investigated the diversity and abundance of comammox bacteria in sediments of a typical urban lake in China, and their ecological relationship with other ammonia-oxidizing micro-organisms. The phylogenetic analysis indicated that comammox clade A existed in the sediment of Lake Donghu, and the comammox bacteria co-existed with ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB) and anaerobic ammonia-oxidizing (anammox) bacteria in the sediment of this lake. The abundances of the ammonia monooxygenase subunit A (amoA) genes for comammox, AOA, AOB and anammox 16S rRNA were 2·43 × 10⁸ , 1·07 × 10⁸ , 3·24 × 10⁷ and 3·21 × 10¹¹ copies per gram dry sediment respectively. Moreover, the amoA gene abundance of comammox was positively correlated with that of AOA and AOB. The redundancy analysis showed that the abundance of the comammox amoA gene was negatively correlated with the concentration of main indicators for nitrogen status in both the sediment and the water column, indicating that eutrophication may inhibit the growth of comammox bacteria.

CONCLUSIONS

Comammox bacteria play an important ecological role in the nitrogen cycle of urban lake sediments.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results indicated comammox bacteria were widespread in urban lakes and eutrophication may inhibit their growth.

Frequency-comb-based laser system producing stable optical beat pulses with picosecond durations suitable for high-precision multi-cycle terahertz-wave generation and rapid detection

We generate temporally modulated optical pulses with a beat frequency of 255 GHz, a duration of 360 ps, and a repetition rate of 2 MHz. The temporal envelope, beat frequency, and repetition rate are computer-programmable. A frequency comb serves as a phase and frequency reference for the locking of two laser lines. The system enables beat frequencies that are adjustable in steps of the frequency comb's repetition rate and exhibit Hz-level precision and accuracy. We expect the optical beat pulses to be well suited for versatile multi-cycle terahertz-wave generation with controllable carrier-envelope phase. We demonstrate that the inherent synchronization of the frequency comb's ultra-short pulse train and the synthesized optical beat (or later the multi-cycle terahertz) pulses enables rapid and phase-sensitive sampling of such pulses.

[Clinical characteristics analysis of children with reversible posterior leukoen-cephalopathy syndrome during the treatment of hematological tumor]

OBJECTIVE

To analyze the clinical characteristics of patients with hematological tumor or disease before and after reversible posterior leukoen-cephalopathy syndrome (RPLS).

METHODS

Five patients were both from Peking University First Hospital Pediatric Hematology-oncology Department in the period from March 2012 to March 2017. The gender, age, BMI, underlying diseases, with or without renal damage, hypertension family history, clinical manifestations of convulsions, hemoglobin, and blood pressure, serum sodium levels before and after convulsion, and other data of the children with RPLS were retrospectively analyzed. In the meantime, we followed up the five patients for 6 months to 66 months, kept a watchful eye on their original condition and the recovery of symptoms and signs of the nervous system. The relevant literature was reviewed.

RESULTS

All of the subjects were females in school-age or pre-school age. The underlying diseases were malignant tumor associated with renal involvement or on one side of nephrectomy in 4 of these subjects, while the other one was refractory autoimmune hemolytic anemia. All of the subjects suffered from mild or moderate anemia. The day before RPLS occurred they received chemotherapy made up with cyclophosphamide, vincristine, and actinomycin-D, or the therapy with cyclosporin A and glucocorticoid. The clinical manifestations were afebrile convulsion after getting up in the mooring or in the afternoon. We observed elevation of blood pressure and cutting down of serum sodium compared with themselves. All of the cases recovered soon after management with diazepam, furosemide and amlodipine besylate. Four of them had a good outcomes and did not remain any sequela, while only one girl became childish in emotion and behavior, and then returned gradually to normal two years later. However, by long-term follow-up, the elevation of blood pressure was mainly reviewed in literature.

CONCLUSION

The patients attacked by RPLS, with hematology or oncology cases, could have the underlying disease of renal damage and anemia. Blood pressure elevation and serum sodium falling down at the same time may play an important role during the occurrence of RPLS. Remaining stable of blood pressure and electrolyte level together will possibly reduce or mitigate RPLS.

The expression significance of serum MiR-21 in patients with osteosarcoma and its relationship with chemosensitivity

OBJECTIVE

To investigate the expression level of serum microRNA-21 (miR-21) in 69 patients with osteosarcoma, to analyze the changes in miR-21 expression in the serum and tumor tissues before and after chemotherapy in patients with osteosarcoma, and to investigate the relationship between the expression of serum miR-21 in patients with osteosarcoma and chemosensitivity.

PATIENTS AND METHODS

Real-time polymerase chain reaction (RT-PCR) was used to detect the expression level of serum miR-21 in 69 patients with osteosarcoma before and after chemotherapy, and analyze the relationship between the expression of miR-21 with tumor necrosis grading and chemosensitivity. The expression level of programmed cell death protein 4 (PDCD4) in tumor tissues of patients with osteosarcoma before and after chemotherapy was detected by Western blot.

RESULTS

The expression level of serum miR-21 in patients with osteosarcoma was significantly higher than that in normal control subjects. The expression of serum miR-21 before and after chemotherapy was positively correlated with the expression of miR-21 in the corresponding tissues. In the group where chemotherapy was effective (the effective group), expression levels of miR-21 in patients with osteosarcoma before and after chemotherapy were significantly different. After chemotherapy, the expression level of target genes of miR-21 was increased, and the follow-up results showed that the 5-year survival rate was relatively higher after surgery.

CONCLUSIONS

The expression level of serum miR-21 in patients with osteosarcoma is closely related to the therapeutic effects of osteosarcoma, which can be used as one of the potential biomarkers and therapeutic targets for the diagnosis and prediction of osteosarcoma.

[Autoimmune disorder secondary to DiGeorge syndrome: a long-term follow-up case report and literature review]

DiGeorge syndrome is the most common chromosome microdeletion disease. The classical complications include congenital heart disease, hypothyroidism, immunodeficiency, facial abnormalities, and hypocalcemia. According to whether there is an absence or hypoplasia of the thymus, DiGeorge syndrome can be divided into two types, complete DiGeorge syndrome and partial DiGeorge syndrome. The patient was a female born with congenital heart disease, facial abnormalities and cleft palate. When the patient went to school, she had learning difficulty and had problems in communication and personal social behavior. Breath-holding occurred when she was 6 years old. She got infections about 2-3 times a year, which was easy to be cured each time. Chromosome microdeletion test of peripheral blood showed the classical 22q11.2 microdeletion, and no evidence showed that she has thymus absence, thus her disease was diagnosed as partial DiGeorge syndrome. When the patient was 6 years old, the blood routine test showed slight thrombocytopenia, and reexaminations after that indicated the similar result. When 9 years old, she was found with anemia and severe thrombocytopenia. At the age of 10, the patient was admitted to our hospital, complaining of petechia in the body and mucous of mouth. According to the various examinations results, doctors eventually considered the situation as an autoimmune disorder phenomenon. After being treated by pulse-dose methylprednisolone for three days, the bleeding ceased. Then the patient orally took prednisone acetate and pulse-dose cyclophosphamide, however the thrombocyte and hemoglobin levels had not been back to a normal range. But when the dose of prednisone acetate was reduced, the blood platelet count declined again while the hemoglobin kept normal. The long-term follow-up of this case lasted for more than 20 years. Until now, the patient is taking orally prednisone acetate as a maintainance treatment, and the anemia has been improved since, but thrombocytopenia still exists. The mechanism of DiGeorge syndrome in combination with immunodeficiency is still unclear. The most likely reason is that this phenomenon has some relationship with the dysfunction of the thymus and finally had an effect on the function of T cells. The clinical manifestation is always stubborn and need treatment and follow-up visit for a long time.

AXSIS: Exploring the frontiers in attosecond X-ray science, imaging and spectroscopy

X-ray crystallography is one of the main methods to determine atomic-resolution 3D images of the whole spectrum of molecules ranging from small inorganic clusters to large protein complexes consisting of hundred-thousands of atoms that constitute the macromolecular machinery of life. Life is not static, and unravelling the structure and dynamics of the most important reactions in chemistry and biology is essential to uncover their mechanism. Many of these reactions, including photosynthesis which drives our biosphere, are light induced and occur on ultrafast timescales. These have been studied with high time resolution primarily by optical spectroscopy, enabled by ultrafast laser technology, but they reduce the vast complexity of the process to a few reaction coordinates. In the AXSIS project at CFEL in Hamburg, funded by the European Research Council, we develop the new method of attosecond serial X-ray crystallography and spectroscopy, to give a full description of ultrafast processes atomically resolved in real space and on the electronic energy landscape, from co-measurement of X-ray and optical spectra, and X-ray diffraction. This technique will revolutionize our understanding of structure and function at the atomic and molecular level and thereby unravel fundamental processes in chemistry and biology like energy conversion processes. For that purpose, we develop a compact, fully coherent, THz-driven atto-second X-ray source based on coherent inverse Compton scattering off a free-electron crystal, to outrun radiation damage effects due to the necessary high X-ray irradiance required to acquire diffraction signals. This highly synergistic project starts from a completely clean slate rather than conforming to the specifications of a large free-electron laser (FEL) user facility, to optimize the entire instrumentation towards fundamental measurements of the mechanism of light absorption and excitation energy transfer. A multidisciplinary team formed by laser-, accelerator,- X-ray scientists as well as spectroscopists and biochemists optimizes X-ray pulse parameters, in tandem with sample delivery, crystal size, and advanced X-ray detectors. Ultimately, the new capability, attosecond serial X-ray crystallography and spectroscopy, will be applied to one of the most important problems in structural biology, which is to elucidate the dynamics of light reactions, electron transfer and protein structure in photosynthesis.

Uptake of 2,4-bis(Isopropylamino)-6-methylthio-s-triazine by Vetiver Grass (Chrysopogon zizanioides L.) from Hydroponic Media

2,4-bis(Isopropylamino)-6-methylthio-s-triazine (prometryn) poses a risk to aquatic environments in several countries, including China, where its use is widespread, particularly due to its chemical stability and biological toxicity. Vetiver grass (Chrysopogon zizanioides L.) was tested for its potential for phytoremediation of prometryn. Vetiver grass was grown in hydroponic media in a greenhouse, in the presence of prometryn, with appropriate controls. Plant uptake and removal of prometryn from the media were monitored for a period of 67 days. The results showed that the removal of the prometryn in the media was expedited by vetiver grass. The removal half-life (t1/2) was shortened by 11.5 days. Prometryn removal followed first-order kinetics (Ct = 1.8070e(-0.0601t)). This study demonstrated the potential of vetiver grass for the phytoremediation for prometryn.

[Inhibition of Sirolimus on the growth of pancreatic carcinoma and its effect on the expression of glucose transporter and hexokinase Ⅱ]

OBJECTIVE

To investigate whether Sirolimus could affect the glycolytic catabolism pathways of pancreatic carcinoma through the control of hypoxia induced factor (HIF-1α) to inhibit the growth of tumor, and explore the potential mechanism of targeting the signaling pathways of mTOR for the treatment of pancreatic carcinoma.

METHODS

Sirolimus was applied to treat the pancreatic carcinoma in nude mice orthotopic transplantation model, its difference with the control group was compared; RT-PCR and Western blot were used to measure the mRNA and protein expression of mTOR, HIF-1α, Glucose carrier protein 1 (GLUT-1) and Hexokinase Ⅱ (HK-Ⅱ), respectively; the changes of activity of HK-Ⅱ in the tumor was determined.

RESULTS

The tumor mass of the control group (1.97±0.21)g was significantly larger than that of the Sirolimus group (0.38±0.10)g (P<0.01), and the volume of the control group (1.40±0.15) mm(3) was significantly larger than that of the Sirolimus group (0.27±0.07) mm(3) (P<0.01). The expressions of mTOR, GLUT-1 and HK-Ⅱ mRNA in the control group were higher than those of the Sirolimus group (P<0.05), while no significant change was observed in the expression of HIF-1α (P>0.05); the expressions of p-mTOR, HIF-1α, GLUT-1 and HK-Ⅱ proteins in the control group were higher than those of the Sirolimus group (P<0.05). The activity of HK-Ⅱ in the control group was higher than that of the Sirolimus group (P<0.05).

CONCLUSION

Sirolimus could affect the expression of GLUT-1 and HK-Ⅱ in pancreatic carcinoma through the effects of HIF-1α to inhibit tumor growth, indicating that blocking the mTOR pathway could control the glycolytic metabolism pathways of pancreatic carcinoma, which may become the new strategy for the treatment of pancreatic carcinoma.