Repair mechanism of radiation-induced salivary gland injury by hypoxia-pretreated human urine-derived stem cell exosomes

OBJECTIVE

To explore the protective effect of human urine-derived stem cell exosomes (hUSC-Exos) on radiation-induced salivary gland (SG) injuries in Sprague Dawley rats.

METHODS

Fresh adult urine was collected, and primary hUSCs were isolated and identified. The hUSCs were hypoxia-pretreated with 1% oxygen for 24 h and then transferred to a normoxic culture environment for 24 h. The hUSC-Exos were collected and identified for exosomes. A radiation-induced injury model was established in the rats, and exosomes were introduced by local injection in the SG and tail vein. The submandibular gland was excised for morphological observation 1 week later. Immunohistochemical detection of the glandular tissue was conducted by α-smooth muscle actin (a-SMA), stem cell growth factor receptor (c-Kit) staining, and periodic acid-Schiff staining. Qualitative polymerase chain reaction and western blot analysis were adopted to detect the gene and protein expression of Wnt3a, GSK3β, and Axin.

RESULTS

In both the normoxic and hypoxic hUSC-Exo groups, microvesicular structures with bilayer membranes of approximately 80 nm in diameter were detected, and the expressions of CD9 and CD63 were detected by nanoflow cytometry. Compared with the control group, in the radiation-induced injury model group, the expression of a-SMA was significantly higher, the expression of c-Kit was significantly lower, and the expressions of Wnt3a, GSK3β, and Axin were significantly upregulated; the differences were statistically significant (p < 0.05). Compared with the model group, in the normoxic and hypoxic hUSC-Exo groups, the expression of a-SMA was significantly decreased, the expression of c-Kit was significantly increased, and the expressions of Wnt3a, GSK3β, and Axin were significantly upregulated; the differences were statistically significant (p < 0.05).

CONCLUSION

Hypoxia-pretreated hUSC-Exos could repair radiation-induced SG injuries by activating the Wnt3a/GSK3β pathway to suppress the expressions of a-SMA and c-Kit.

[Identification of the priority conservation areas of national park: A case study of Lishui City, Zhejiang Province, China]

It is the goal of protected area management to make full use of limited resources to better protect biodiversity. Currently, the main tasks of developing national park system in China are to combine conservation features, optimize the spatial network of protected areas, and identify the prio-rity conservation areas of national parks effectively. In this study, we assessed the spatial distribution of key ecosystem services (carbon sequestration, oxygen release, hydrological regulation, water resources, and soil retention) using ecological model, and simulated the distribution of suitable habitats for 37 endangered species by MaxEnt in Lishui City, Zhejiang Province. The irreplaceability index of each planning unit in Lishui was calculated on the 0.4 km×0.4 km grid using the systema-tic conservation planning model (MARXAN), setting key ecosystem services and endangered species as the conservation objects. Combined with the local management needs, the priority protection areas of national parks were identified comprehensively. The results showed that during 2005 to 2015, the annual carbon storage, oxygen release, hydrological regulation, water resource, and soil retention in the study area was 0.05 kg C·m^-2·a^-1, 0.13 kg O₂·m^-2·a^-1, 83.25×10⁸ m³·a^-1, 803 mm·a^-1, and 95.53 t·hm^-2·a^-1, respectively. The irreplaceability index of different land use types was significantly different. The irreplaceability index of forest, river and reservoir, garden, cultivated land, residential land was 50-100, 60-100, 30-50, 15-35, 0-25, respectively. The priority conservation areas accounted for 11.8% of the study area. This study put forward a systematic conservation planning idea combining biodiversity and ecosystem services, which could provide a useful framework and technical support for optimizing the network layout of protected areas and priority conservation areas of national parks, and help to enhance the overall effectiveness of the establishment of the protected areas system with national parks as its main type in China.

Development of a novel score to predict probability of growth without growth hormone after resection of paediatric craniopharyngiomas: relative to tumour growth pattern

OBJECTIVE

Some patients with paediatric craniopharyngiomas (PCs) showed normal growth despite growth hormone deficiency, which is known as growth without GH (GWGH); however, its mechanism remains unclear. We aimed to develop a novel clinical score to predict the probability of GWGH in PCs.

METHODS

A total of 708 PC patients were prospectively enrolled from six hospitals, among which 431 patients were finally included. Data from four of the six hospitals (n = 325) were used to develop the innovative clinical score (ICS), which was further validated using the data from the other two hospitals (n = 106). To establish and validate the ICS, sequential logistic regression was used to analyse the clinical characteristics including tumour growth pattern and tumour size and so on. Furthermore, C-statistic was employed to calibrate the discriminatory ability of the established clinical score, while a calibration plot was adopted for further assessment.

RESULTS

The overall incidence of GWGH was 16.9% (73/431). The ICS ranged from 2 to 23, with an optimism-corrected C-statistic of 0.820, Furthermore, the optimism-corrected C-statistic of external validation was 0.835, indicating good discriminatory power and robustness of the clinical score. Additionally, no apparent overestimation or underestimation was observed in the calibration plots, which showed excellent calibration power of the clinical score.

CONCLUSIONS

Based on tumour growth patterns and PC patients' clinical characteristics, individualized surgical strategies were promising to achieve long-term effective management of PC patients. The ICS is valuable for the evaluation of probability of developing postoperative GWGH.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT00949156.

Polar Metamaterials: A New Outlook on Resonance for Cloaking Applications

Rotationally resonant metamaterials are leveraged to answer a longstanding question regarding the existence of transformation-invariant elastic materials and the ad hoc possibility of transformation-based passive cloaking in full plane elastodynamics. Combined with tailored lattice geometries, rotational resonance is found to induce a polar and chiral behavior, that is, a behavior lacking stress and mirror symmetries, respectively. The central, and simple, idea is that a population of rotating resonators can exert a density of body torques strong enough to modify the balance of angular momentum on which hang these symmetries. The obtained polar metamaterials are used as building blocks of a cloaking device. Numerical tests show satisfactory cloaking performance under pressure and shear probing waves, further coupled through a free boundary. The work sheds new light on the phenomenon of resonance in metamaterials and should help put transformation elastodynamics on equal footing with transformation acoustics and optics.

[Single-stage repair of penile urethral stricture using combined dorsal onlay oral mucosa grafting with ventral onlay penile skin flap]

OBJECTIVE

To evaluate the clinical effect of single-stage repair of penile urethral stricture using combined dorsal onlay oral mucosa grafting with ventral onlay penile skin flap.

METHODS

We retrospectively reviewed the clinical database of 22 male patients with penile urethral stricture who received single-stage repair using combined dorsal onlay oral mucosa grafting with ventral onlay penile skin flap from November 2015 to October 2018. All the cases had no complications, such as skin fistula. The causes of stricture included iatrogenic (14/22, 63.6%), inflammation (2/22, 9.1%) and idiopathic (6/22, 27.3%). A ventral urethrotomy was made in the segment of stricture and extended proximally and distally until the normal calibre urethra was encountered. The oral mucosa graft was secured to the corpus spongiosum in dorsal onlay fashion or underlying corpora cavernosum after resection of the severe scarred urethra. Then the prepared Orandi fasciocutaneous penile skin flap was secured to edges of corpus spongiosum or oral mucosa graft. A 16 F or 14 F Foley catheter was left in situ for a minimum of 3 weeks, at which time a urethrogram was performed to look for extravasation, and the urethroscopy was performed if necessary. Success was defined as an open urethra with Qmax≥15 mL/s and no need for further surgical intervention.

RESULTS

all the 22 patients with a mean age of 52.6 (18-73) years underwent the combined tissue-transfer technique. The mean length of the penile urethral stricture was 5.3 (2.5-10.0) cm and the mean preoperative Qmax was 6.7 mL/s. the mean length of oral mucosa grafts and fasciocutaneous skin flaps were 5.5 (3.2-10.5) cm and 6.0 (3.5-11.0) cm, respectively. The mean operation time was 225 (150-420) minutes and the mean evaluated blood loss was 53 (20.0-110.0) mL. The grafts included buccal mucosa (19/22, 86.4%) and lingual mucosa (3/22, 13.6%). The mean postoperative Q max was 21.2 (15-32) mL/s. A case of skin fistula and 2 cases of recurrent stricture were found, so the technique success rate was 81.8% (18/22) at a mean follow-up of 20.5 (5-51) months. The perioperative complications included 2 cases of infection and skin necrosis, which healed well after conservative treatment.

CONCLUSION

Single-stage repair of penile urethral stricture using combined dorsal onlay oral mucosa grafting with ventral onlay penile skin flap appears to be an excellent option to repair penile urethral stricture with unsalvageable urethral plate and the penile skin is available. The present clinical series showed a successful rate of 81.8% (18/22).

[Application of closed negative pressure irrigation and suction device in the treatment of high perianal abscess]

Objective: To explore the efficacy of closed negative pressure irrigation and suction device (Patent number: Z200780013509.8) in the treatment of high perianal abscess. Methods: From January 2015 to December 2016, ≥18-year-old patients with primary high perianal abscess who were treated at our department were prospectively enrolled. Exclusion criteria: (1) recurrent perianal abscess; (2) complicated with anal fistula formation; (3) preoperative, intraoperative or postoperative physical therapy, and curettage treatment, negative pressure irrigation; (4) Crohn's disease-related perianal abscess; (5) with immunosuppressive status, such as transplant recipients; (6) co-existence of malignant tumors, such as leukemia; (7) with diabetes; (8) those who could not receive long-term follow-up and were not suitable to participate in this study. According to the random number table method, the patients were randomly divided into negative pressure irrigation and suction group and routine drainage group. All patients were clearly diagnosed and the location and size of the perianal abscess were marked before surgery. These two groups were treated as follows: (1) Negative pressure irrigation and suction group: the skin was incised at a diameter of 1-2 cm at the site where the abscess fluctuated most obviously. After the abscess was removed, a closed negative pressure irrigation and suction device was installed and the pressure of -200 to -100 mmHg (1 mmHg=0.133 kPa) was maintained to keep the abscess cavity collapsed. Generally, the irrigation was stopped 5 days later or when the drainage was clear. The closed vacuum suction was maintained for 2 additional days, before the wound was sutured. (2) Conventional drainage group: conventional incision and drainage was carried out. The skin was cut at a diameter of 8 to 10 cm at the site of abscess with most obvious fluctuation. After the abscess was removed, normal saline gauze was used for dressing. Dressing was changed regularly until the wound healed. The efficacy, operative time, intraoperative bleeding, incision length, frequency of dressing change, pain index (visual analogue score, VAS score), postoperative healing time, complications, recurrence rate of perianal abscess, anal fistula formation rate were observed. The t test and χ² test were used for comparison between the 2 groups. Results: There were both 40 patients in the negative pressure irrigation and suction group and the conventional drainage group. There were 28 males and 12 females in negative pressure irrigation and suction group with a mean age of (38.3±12.0) years and mean disease course of (6.6±2.1) days. The abscess in pelvic-rectal space accounted for 50.0% (20/40) and the mean diameter of abscess was (8.0±3.7) cm. There were 26 males and 14 females in the conventional drainage group with a mean age of (37.1±11.8) years and mean disease course of (6.4±2.5) days. The abscess in pelvic-rectal space accounted for 55.0% (22/40) and the diameter of abscess was (8.2±3.5) cm. The differences in baseline data between two groups were not statistically significant (all P>0.05). Both groups successfully completed the operation. There was no significant difference in operative time between two groups (P>0.05). As compared to conventional drainage group, intraoperative blood loss in negative pressure irrigation and suction group was less [(12.1±5.5) ml vs. (18.3±4.4) ml, t=5.606, P<0.001], incision length was shorter [(2.3±0.8) cm vs. (7.6±1.7) cm, t=17.741, P<0.001], postoperative VAS pain scores at 1-, 3-, 7-, and 14-day after operation were lower [3.7±1.4 vs. 7.6±1.8, t=10.816, P<0.001; 3.0±1.3 vs. 6.8±1.6, t=11.657, P<0.001; 2.7±0.9 vs. 5.1±1.1, t=10.679, P<0.001; 1.2±0.3 vs. 1.6±0.4, t=5.060, P=0.019], the dressing change within 7 days after operation was less (3.5±1.2 vs. 12.6±2.7, t=19.478, P<0.001), postoperative healing time was shorter [(10.4±3.0) d vs. (13.5±3.8) d, t=4.049, P<0.001] and postoperative complication rate was lower [17.5% (7/40) vs. 2.5% (1/40), χ²=5.000, P=0.025]. During follow-up of 12 to 36 (24±5) months, the recurrence rate of perianal abscess within 1 year after operation and anal fistula formation rate in negative pressure irrigation and suction group were lower than those in conventional drainage group [5.0% (2/40) vs. 20.0% (8/40), χ²=4.114, P=0.042 and 2.5% (1/40) vs. 17.5% (7/40), χ²=5.000, P=0.025, respectirely]. The one-time cure rate of negative pressure irrigation and suction group and conventional drainage group was 92.5% (37/40) and 62.5%(25/40), respectirely (χ²=10.323, P=0.001). Conclusions: The application of the negative pressure irrigation and suction device in the treatment of high perianal abscess can improve the efficiency of one-time cure, reduce postoperative pain, accelerate healing time, decrease the morbidity of postoperative complication and the rates of abscess recurrence and anal fistula formation, indicating an improvement of the treatment.

["3-step" strategy of transperineal anastomotic urethroplasty for the simple pelvic fracture urethral distraction defect in male patients]

OBJECTIVE

To evaluate the clinical effect of "3-step" strategy of transperineal anastomotic urethroplasty for the simple pelvic fracture urethral distraction defect in male patients.

METHODS

We retrospectively reviewed the clinical data of 162 male patients with simple traumatic posterior urethral stricture or stenosis admitted from January 2014 to October 2015. All had no complex complications, such as urethroperineal fistulas or urethrorectal fistulas. Before referral to Department of Urology, Beijing Jishuitan Hospital, 64 patients had undergone previous treatments: urethroplasty in 30 patients (18.5%), early urethral realignment in 17 patients (10.5%) and 17 patients (10.5%) who had undergone internal urethrotomy. The remaining 98 patients received the suprapubic cystostomy in the acute setting. All of them had received transperineal anastomotic urethroplasty with "3-step" strategy. Step 1, the bulbar urethra was circumferentially mobilized and tension-free anastomosis could be performed after the scar was completely incised and removed. Step 2, if after step 1 a tension-free anastomosis could not be achieved, were routed the distal urethra between the separated corporal bodies. Step 3, if the anastomosis still seemed to be under tension, we could perform pubectomy, partial or total removal, to get a better exposure of the apex of the prostate-membranous urethra.

RESULTS

The mean age of the patients included in this study was 36.3 years (rangingfrom 16-74 years). The mean time between incidents and operation was 13.5 months (ranging from 3-124 months) and the mean length of stricture was 2.7 cm (ranging from 0.5-6.5 cm).The mean time of operation was 92 (45-240) min and the mean evaluated blood lose was 120 (60-800) mL. Three patients (1.9%) received blood transfusing during or after the operations. The numbers of the patients who completed step 1, step 2 and step 3 were 50(30.9%), 74(45.7%) and 38(23.5%), respectively. There were 4 (2.5%) patients who needed the combined transpubic and transperineal approach for tension-free anastomosis after removing an entire wedge of anterior pubis. The mean follow-up was 19.5 months and 18 patients' strictures recurred with manifestation of decreased stream of dysuria. The overall success rate was 88.9%(144/162).

CONCLUSION

Based on the "3-step" strategy of transperineal anastomotic urethroplasty, patients with simple PFUDD can achieve a tension-free anastomosis. The present clinical data showed a successful rate of 88.9% (144/162).

Kirigami-based Elastic Metamaterials with Anisotropic Mass Density for Subwavelength Flexural Wave Control

A novel design of an elastic metamaterial with anisotropic mass density is proposed to manipulate flexural waves at a subwavelength scale. The three-dimensional metamaterial is inspired by kirigami, which can be easily manufactured by cutting and folding a thin metallic plate. By attaching the resonant kirigami structures periodically on the top of a host plate, a metamaterial plate can be constructed without any perforation that degrades the strength of the pristine plate. An analytical model is developed to understand the working mechanism of the proposed elastic metamaterial and the dispersion curves are calculated by using an extended plane wave expansion method. As a result, we verify an anisotropic effective mass density stemming from the coupling between the local resonance of the kirigami cells and the global flexural wave propagations in the host plate. Finally, numerical simulations on the directional flexural wave propagation in a two-dimensional array of kirigami metamaterial as well as super-resolution imaging through an elastic hyperlens are conducted to demonstrate the subwavelength-scale flexural wave control abilities. The proposed kirigami-based metamaterial has the advantages of no-perforation design and subwavelength flexural wave manipulation capability, which can be highly useful for engineering applications including non-destructive evaluations and structural health monitoring.

Non-reciprocal wave propagation in modulated elastic metamaterials

Time-reversal symmetry for elastic wave propagation breaks down in a resonant mass-in-mass lattice whose inner-stiffness is weakly modulated in space and in time in a wave-like fashion. Specifically, one-way wave transmission, conversion and amplification as well as unidirectional wave blocking are demonstrated analytically through an asymptotic analysis based on coupled mode theory and numerically thanks to a series of simulations in harmonic and transient regimes. High-amplitude modulations are then explored in the homogenization limit where a non-standard effective mass operator is recovered and shown to take negative values over unusually large frequency bands. These modulated metamaterials, which exhibit either non-reciprocal behaviours or non-standard effective mass operators, offer promise for applications in the field of elastic wave control in general and in one-way conversion/amplification in particular.

Wave propagation and absorption of sandwich beams containing interior dissipative multi-resonators

In this study, a sandwich beam with periodic multiple dissipative resonators in the sandwich core material is investigated for broadband wave mitigation and/or absorption. An analytical approach based on the transfer matrix method and Bloch theorem is developed for both infinite and finite sandwich structures. Wave attenuation constants are theoretically obtained to examine the effects of various system parameters on the position, width and wave attenuation performance of the band gaps. The wave absorption coefficient of the sandwich beam is quantitatively studied to distinguish wave attenuation mechanisms caused by reflection and absorption. It is numerically demonstrated that a transient blast-induced elastic wave with broadband frequencies can be almost completely mitigated or absorbed at a subwavelength scale. The results of this study could be used for developing new multifunctional composite materials to suppress impact-induced and/or blast-induced elastic waves which may cause severe local damage to engineering structures.

Enhanced flexural wave sensing by adaptive gradient-index metamaterials

Increasing sensitivity and signal to noise ratios of conventional wave sensors is an interesting topic in structural health monitoring, medical imaging, aerospace and nuclear instrumentation. Here, we report the concept of a gradient piezoelectric self-sensing system by integrating shunting circuitry into conventional sensors. By tuning circuit elements properly, both the quality and quantity of the flexural wave measurement data can be significantly increased for new adaptive sensing applications. Through analytical, numerical and experimental studies, we demonstrate that a metamaterial-based sensing system (MBSS) with gradient bending stiffness can be designed by connecting gradient negative capacitance circuits to an array of piezoelectric patches (sensors). Furthermore, we demonstrate that the proposed system can achieve more than two orders of magnitude amplification of flexural wave signals to overcome the detection limit. This research encompasses fundamental advancements in the MBSS with improved performance and functionalities, and will yield significant advances for a range of applications.

A single-phase elastic hyperbolic metamaterial with anisotropic mass density

Wave propagation can be manipulated at a deep subwavelength scale through the locally resonant metamaterial that possesses unusual effective material properties. Hyperlens due to metamaterial's anomalous anisotropy can lead to superior-resolution imaging. In this paper, a single-phase elastic metamaterial with strongly anisotropic effective mass density has been designed. The proposed metamaterial utilizes the independently adjustable locally resonant motions of the subwavelength-scale microstructures along the two principal directions. High anisotropy in the effective mass densities obtained by the numerical-based effective medium theory can be found and even have opposite signs. For practical applications, shunted piezoelectric elements are introduced into the microstructure to tailor the effective mass density in a broad frequency range. Finally, to validate the design, an elastic hyperlens made of the single-phase hyperbolic metamaterial is proposed with subwavelength longitudinal wave imaging illustrated numerically. The proposed single-phase hyperbolic metamaterial has many promising applications for high resolution damage imaging in nondestructive evaluation and structural health monitoring.

The combination therapy of high-intensity focused ultrasound with radiotherapy in locally advanced pancreatic carcinoma

BACKGROUND

The aim of the present study is to evaluate the effectiveness of the combined application of high-intensity focused ultrasound (HIFU) and radiotherapy in the treatment of locally advanced pancreatic carcinoma (LAPC).

METHODS

A total number of sixteen patients with LAPC started treatment beginning with HIFU and radiotherapy 1 week after the HIFU treatment. Evaluation of the effectiveness of treatment was performed using main clinical symptoms, serum levels of CA-19-9, Response Evaluation Criteria in Solid Tumors (RECIST) guidelines, and the Kaplan-Meier method for estimating median overall survival (OS). The occurrence of adverse reactions was recorded.

RESULTS

The main clinical symptoms including abdominal pain and lower back pain were alleviated, and the mean visual analog scale (VAS) pain score declined from 5.1 points to just 3.3 points immediately after the HIFU treatment. The median pain relief time was 5.6 months after radiotherapy, serum CA-19-9 levels began to decrease significantly 1 week after the HIFU treatment, from 102.1 to 60.8 U/ml, and the median continuous decline time was 4.3 months after radiotherapy. Partial response (PR) was observed in seven of sixteen patients, with stable disease (SD) in four patients, and progressive disease (PD) in the remaining five patients at 6 months after radiotherapy. Serum levels of amylopsin and lipase were not elevated to abnormal levels. The median OS was 14 months. No serious adverse reactions occurred.

CONCLUSIONS

Treatment with both HIFU and radiotherapy can quickly improve symptoms and the quality of life and prolong survival lengths. This combination might be a promising therapeutic treatment for patients with LAPC.

Genetic mechanism associated with congenital cytomegalovirus infection and analysis of effects of the infection on pregnancy outcome

We aimed to compare the diagnostic value of various detection methods for cytomegalovirus (CMV) infection, to investigate the genetic mechanism associated with CMV infection in pregnant women, and to analyze the risk of sequelae development in fetuses with CMV infection. A total of 300 participants who had the same immunosuppressive regimen and received preemptive therapy for CMV infection were prospectively enrolled in this study; they included 289 vaccine trial participants. The gB-absorbed CMV IgG assay was performed for each vaccine trial participant. The healthy women were divided into 2 groups, and amniotic fluids were collected from them at 15-18 weeks of gestation to test for CMV seropositivity before conception by using IgM specific antibodies, CMV-DNA, and IgG analysis. In 104 cases, cord blood sera and urine specimens were also collected from the infants and examined. The sensitivity and specificity of immediate-early messenger RNA and pp67 (late) messenger RNA detection by the nucleic acid sequence-based amplification technique was comparable to those of virus isolation and PCR. Furthermore, an association between single nucleotide polymorphisms in the TLR-2 gene and congenital CMV infection was observed and confirmed. Moreover, CMV infection during early pregnancy has been shown to have a much more severe effect on the pregnancy outcome compared to infection during later stages of pregnancy.

Therapeutic efficacy of paclitaxel and carboplatin via arterial or venous perfusion in rabbits with VX-2 tongue cancer

OBJECTIVE

This study aimed to investigate the therapeutic efficacy of paclitaxel in combination with carboplatin in different ways in rabbits with VX-2 tongue cancer.

METHODS

Rabbit VX-2 tongue cancer model was established and animals were then divided into 6 groups, in which animals received perfusion with paclitaxel liposome and carboplatin via the lingual artery, with free paclitaxel and carboplatin via the lingual artery, with 5% glucose via the lingual artery, with paclitaxel liposome and carboplatin via ear vein, with free paclitaxel and carboplatin via the ear vein and with 5% glucose via the ear vein independently. When the maximum diameter of cervical lymph nodes was larger than 5 mm, chemotherapy was initiated. Seven days later, flow cytometry and immunohistochemistry were performed to detect the apoptosis of VX-2 cells and P53 expression in the primary cancer and metastatic lymph nodes.

RESULTS

Targeted arterial perfusion with paclitaxel liposome in combination with carboplatin was more effective to induce the apoptosis of cancer cells in the primary cancer and metastatic lymph nodes and inhibit their proliferation.

CONCLUSION

Targeted arterial perfusion with paclitaxel liposome in combination with carboplatin is effective to reduce tumor size, attenuate the surgery induced injury and improve the post-operative quality of life of oral cancer patients.

Functional regeneration of irradiated salivary glands with human amniotic epithelial cells transplantation

This study aimed to investigate the functional restoration of radiation-damaged salivary gland with human amniotic epithelial cells (hAECs) transplantation by intra-glandular injection. hAECs were isolated from the amnion tissues. After primary culture, the phenotype of hAECs of the second passage was identified by flow cytometry (FCM) and immunocytochemical staining. Then, hAECs were intra-glandularly injected into the irradiated glands of mice. At different time points after transplantation, the glands were collected for hematoxylin-eosin (HE) staining and immunofluorescence staining, and the saliva flow rate was also determined. Results showed these cells were positive for CD29, CD73 and CK19 and negative for CD44, CD34, CD45 and CD71. The transplanted hAECs in the recipient glands could differentiate into acinar-like cells and resulted in morphological and functional restoration of salivary gland.

Transdifferentiation of human amniotic epithelial cells into acinar cells using a double-chamber system

This study investigated the transdifferentiation of stem cells from human amnion tissue into functional acinar cells (ACs) using a co-culture system. Human amniotic epithelial cells (hAECs) were isolated from amnion tissue by mechanical mincing and enzymatic digestion. After primary culture, the phenotype of the cells was identified by flow cytometry (FCM) and immunocytochemical staining. hAECs were co-cultured with submandibular gland acinar cells of SD rats using a double-chamber system. The expression of α-amylase was determined by immunocytochemical method and fluorescent real-time quantitative reverse transcription polymerase chain reaction (RT-PCR) after induction for 1 and 2 weeks, respectively. Digestion with trypsin is an effective method for isolating hAECs from amnion tissue. These cells were positive for CD29 and CK19 and weakly positive for CD44 and α-amylase. Within 2 weeks, α-amylase in hAECs increased with induction time. The expression of α-amylase in hAECs was increased 3.38-fold after co-culturing for 1 week. This ratio increased to 6.6-fold, and these cells were positive for mucins, after co-culturing for 2 weeks. hAECs possess the potential to differentiate into ACs in vitro. They might be a stem cell resource for clinical applications of cell replacement therapy in salivary gland dysfunction diseases.

Sentinel lymph node biopsy using carbon nanoparticles for Chinese patients with papillary thyroid microcarcinoma

AIMS

To compare the efficacies of methylene blue (MB) and carbon nanoparticles (CNs) as tracers for sentinel lymph node biopsy (SLNB), and assess the value of SLNB in predicting the cervical LN status of patients with thyroid microcarcinoma.

METHODS

This retrospective analysis comprised 200 thyroid microcarcinoma patients who underwent intraoperative SLNB. Among them, 100 patients were injected with MB dye. The other 100 patients received a CN suspension injection. Routine pathological examination was performed in all resected specimens.

RESULTS

SLNs detected in the experimental and control groups were 126 and 102, respectively, of which the metastatic LNs confirmed by histopathology were 77 and 48, respectively. The staining rate of cervical level VI LNs in the experimental group was significantly higher than that in the control group (P<0.001). For the CN method, the sensitivity, specificity, accuracy rate, and false negative rate were 93.3%, 100%, 97%, and 5.2%, respectively, whereas the corresponding figures for the MB method were 80.6%, 100%, 93%, and 9.9%, respectively. The positive rate of cancer metastases for SLNs in the experimental group was 61.1%, which is significantly higher than that in the control group (47.1%; P=0.034).

CONCLUSIONS

In contrast to the MB method, CNs can maintain the durability of SLN imaging and accurately forecast the LN status of patients with thyroid microcarcinoma; in addition, the CN method was found to be feasible and repeatable. The CN method better aids the screening and selection of patients who are most likely to benefit from cervical LN dissection.

Treating sewage using coimmobilized system of Chlorella pyrenoidosa and activated sludge

Chlorella pyrenoidosa was coimmobilized with activated sludge to produce algae-bacteria beads for sewage treatment. Hydrolysis/acidogenesis pretreatment could improve the symbiotic microenvironment of coimmobilized Chlorella pyrenoidosa and activated sludge, and as a result, promote the removal of nutrients (COD(cr), inorganic nitrogen and inorganic phosphorus) in the sewage. A photo-bioreactor combining hydrolysis/acidogenesis pretreatment and coimmobilized technique was designed to treat sewage continuously. The results show that, the removal efficiencies of COD(cr), NH4(+)-N and TP reached steady state after 4-days of experiment. The removal efficiencies of COD(cr), NH4(+)-N and TP were 59.6%, 59.0% and 60.3% respectively.

3-[2,4-Dimethoxybenzylidene]anabaseine (DMXB) selectively activates rat alpha7 receptors and improves memory-related behaviors in a mecamylamine-sensitive manner

The alpha7 nicotinic receptor agonist 3-[2,4-dimethoxybenzylidene]anabaseine (DMXB; GTS-21) was investigated for its ability to: (1) activate a variety of nicotinic receptor subtypes in Xenopus oocytes; (2) improve passive avoidance and spatial Morris water task performances in mecamylamine-sensitive manners in bilaterally nucleus basalis lesioned rats; and (3) elevate high-affinity [3H]acetylcholine (ACh) and high-affinity alpha-[125I]bungarotoxin binding in rat neocortex following 2 weeks of daily injections. DMXB (100 microM) activated alpha7 homo-oligomeric receptors, without significant activity at alpha2-, alpha3- and alpha4-containing subtypes. Mecamylamine blocked rat alpha7 receptors weakly if co-administered with agonist, but much more potently when pre-applied. Bilateral ibotenic acid lesions of the nucleus basalis interfered with passive avoidance and spatial memory-related behaviors. DMXB (0.5 mg/kg, i.p.) improved passive avoidance behavior in lesioned animals in a mecamylamine-sensitive manner. DMXB (0.5 mg/kg 15 min before each session) also improved performance in the training and probe components of the Morris water task. DMXB-induced improvement in the probe component but not the training phase was mecamylamine-sensitive. [3H]ACh binding was elevated after 14 days of daily i.p. injections with 0.2 mg/kg nicotine but not after 1 mg/kg DMXB. Neither drug elevated high-affinity alpha-[125I]bungarorotoxin binding over this interval.

The adsorption behaviour of dimethyltin from seawater onto sedimentary phase in Tianjin Harbor

The adsorption of dimethyltin from a seawater matrix onto suspended particulate matter was studied. The influences of pH and salinity, adsorption isotherms at various temperatures, and the adsorption rate under certain experimental conditions were determined. It was found that the adsorption capacity was highest at c. pH 6 and decreased with increasing salinity. The adsorption behaviour at various temperatures was described best by a Langmuir isotherm. The adsorption capacity of dimethyltin was higher in natural seawater than in artificial seawater at the same temperature.

Observation of molecular vibrations in the time domain with incoherent laser pulses

With the method of self-diffraction of incoherent light, molecular vibrations were observed in real time in various dye molecules pumped near the absorption edge. In Rhodamine 560, 35-fsec oscillations in the signal were measured, which corresponds to a vibrational frequency of 1000 cm(-1). Simultaneously, this technique can be used to deduce the ultrafast dephasing times in the molecular vibrational quasi-continuum. Dephasing times of 20 and 150 fsec were observed in Rhodamine 590 and Rhodamine 560, respectively.