Chromatin and gene expression changes during female Drosophila germline stem cell development illuminate the biology of highly potent stem cells

Highly potent animal stem cells either self renew or launch complex differentiation programs, using mechanisms that are only partly understood. Drosophila female germline stem cells (GSCs) perpetuate without change over evolutionary time and generate cystoblast daughters that develop into nurse cells and oocytes. Cystoblasts initiate differentiation by generating a transient syncytial state, the germline cyst, and by increasing pericentromeric H3K9me3 modification, actions likely to suppress transposable element activity. Relatively open GSC chromatin is further restricted by Polycomb repression of testis or somatic cell-expressed genes briefly active in early female germ cells. Subsequently, Neijre/CBP and Myc help upregulate growth and reprogram GSC metabolism by altering mitochondrial transmembrane transport, gluconeogenesis, and other processes. In all these respects GSC differentiation resembles development of the totipotent zygote. We propose that the totipotent stem cell state was shaped by the need to resist transposon activity over evolutionary timescales.

Differentiating Drosophila female germ cells initiate Polycomb silencing by regulating PRC2-interacting proteins

Polycomb silencing represses gene expression and provides a molecular memory of chromatin state that is essential for animal development. We show that Drosophila female germline stem cells (GSCs) provide a powerful system for studying Polycomb silencing. GSCs have a non-canonical distribution of PRC2 activity and lack silenced chromatin like embryonic progenitors. As GSC daughters differentiate into nurse cells and oocytes, nurse cells, like embryonic somatic cells, silence genes in traditional Polycomb domains and in generally inactive chromatin. Developmentally controlled expression of two Polycomb repressive complex 2 (PRC2)-interacting proteins, Pcl and Scm, initiate silencing during differentiation. In GSCs, abundant Pcl inhibits PRC2-dependent silencing globally, while in nurse cells Pcl declines and newly induced Scm concentrates PRC2 activity on traditional Polycomb domains. Our results suggest that PRC2-dependent silencing is developmentally regulated by accessory proteins that either increase the concentration of PRC2 at target sites or inhibit the rate that PRC2 samples chromatin.

Transcriptomic analysis by RNA sequencing characterises malignant progression of canine insulinoma from normal tissue to metastatic disease

Insulinomas (INS) are the most common human and canine functioning pancreatic neuroendocrine tumours. The long-term prognosis for malignant INS is poor, because micrometastases are frequently missed during surgery. As human and canine malignant INS share clinical and histopathological features, dogs have been proposed as models for INS research. Using RNA-sequencing, we conducted a pilot study to better understand the underlying molecular mechanisms of canine INS. Normal canine pancreas and lymph node control tissues were compared with primary INS and INS-metastatic lymph nodes, revealing more than 3,000 genes differentially expressed in normal pancreas compared to primary INS. Only 164 genes were differentially expressed between primary INS and INS-metastatic lymph nodes. Hierarchical clustering analysis demonstrated similar genetic profiles in normal pancreas and early clinical stage primary INS, whereas late clinical stage primary INS resembled the genetic profile of INS-metastatic lymph nodes. These findings suggest that markers of malignant behaviour could be identified at the primary site of the disease. Finally, using the REACTOME pathways database, we revealed that an active collagen metabolism, extracellular matrix remodelling, beta-cell differentiation and non-beta-cell trans-differentiation might cause disease progression and hyperinsulinism in INS, identifying major pathways worthy of future research in this currently poorly controlled disease.

[Rapamycin in the treatment of renal diseases associated with tuberous sclerosis complex]

Objective: To investigate the efficacy and safety of rapamycin in children with tuberous sclerosis complex (TSC) associated renal disease. Methods: A prospective self-control study was conducted. The clinical data of 92 children diagnosed with tuberous sclerosis complex associated kidney disease at the People's Liberation Army General Hospital from January 2011 to January 2019 were collected. The long-term rapamycin treatment for all patients initiated at 1 mg/(m(2)·d), which was gradually adjusted to reach a blood concentration of 5-10 μg/L. The changes of the maximum diameter of renal lesions in children after rapamycin treatment were observed and analyzed with Wilcoxon test. Results: Ninety-two children, including 52 males and 40 females, who met the criteria were analyzed. Sixty patients had only renal angiomyolipoma(RAML), while 24 patients had only multiple renal cysts(MRC), and 8 patients had both lesions. The age of TSC diagnosis was 16.0 (7.0, 42.0) months, and the age of initial treatment with rapamycin was 63.5 (21.0, 103.0) months. The follow-up lasted for 12.0 (4.0, 23.0) months. Sequencing of TSC1 and TSC2 genes was performed in 54 children with TSC, including 3 patients (6%) with mutations in TSC1 gene and 51 patients (94%) with mutations in TSC2 gene. The maximum RAML diameter before treatment was 7.0 (4.0, 9.0) mm. The best effect reached at 3 months of treatment, with the diameter of 4.0 (0,7.0) mm. The maximum diameters at 6 months, 1 year and 1-2 years were 5.0 (0,9.8) mm, 5.0 (1.5, 8.5) mm, 5.5 (3.0, 9.0) mm, respectively, and were significantly different from the baseline (Z=-2.404,-2.350,-2.750,P=0.016,0.019,0.006, respectively). The maximum diameter after 2-3 years, and ≥3 years were 5.0 (3.9,7.0) mm and 6.0 (1.0, 11.0) mm, without significant difference from the baseline (Z=-0.856,-0.102,P=0.393,0.919, respectively).The maximum diameters of MRC after 3 months, 6 months, 1 year,1-2 years, 2-3 years, and ≥3 years were 11.0 (5.0, 14.0) mm,3.0 (0.0,11.0) mm,5.0 (0,21.0) mm,0 (0,14.0) mm,0 (0,10.0) mm, and 0 (0,18.3) mm, respectively, but were not significantly different rom the baseline (7.0 (5.0, 15.7) mm)(Z=-0.944,-1.214,-1.035,-1.896,-1.603,-1.214,P=0.345,0.225,0.301,0.058,0.109,0.225, respectively).Twenty-nine patients (32%) had oral ulcers during the entire treatment period, and no serious adverse reactions were observed. Conclusions: Rapamycin could decrease the diameter of TSC-related RAML, but could not inhibit the growth of cysts. It is well tolerated in the treatment of renal diseases associated with tuberous sclerosis complex.

Notch pathway inhibition targets chemoresistant insulinoma cancer stem cells

Insulinomas (INS) are the most common neuroendocrine pancreatic tumours in humans and dogs. The long-term prognosis for malignant INS is still poor due to a low success rate of the current treatment modalities, particularly chemotherapy. A better understanding of the molecular processes underlying the development and progression of INS is required to develop novel targeted therapies. Cancer stem cells (CSCs) are thought to be critical for the engraftment and chemoresistance of many tumours, including INS. This study was aimed to characterise and target INS CSCs in order to develop novel targeted therapies. Highly invasive and tumourigenic human and canine INS CSC-like cells were successfully isolated. These cells expressed stem cell markers (OCT4, SOX9, SOX2, CD133 and CD34), exhibited greater resistance to 5-fluorouracil (5-FU) and demonstrated a more invasive and tumourigenic phenotype in vivo compared to bulk INS cells. Here, we demonstrated that Notch-signalling-related genes (NOTCH2 and HES1) were overexpressed in INS CSC-like cells. Protein analysis showed an active NOTCH2-HES1 signalling in INS cell lines, especially in cells resistant to 5-FU. Inhibition of the Notch pathway, using a gamma secretase inhibitor (GSI), enhanced the sensitivity of INS CSC-like cells to 5-FU. When used in combination GSI and 5-FU, the clonogenicity in vitro and the tumourigenicity in vivo of INS CSC-like cells were significantly reduced. These findings suggested that the combined strategy of Notch signalling inhibition and 5-FU synergistically attenuated enriched INS CSC populations, providing a rationale for future therapeutic exploitation.

Phenotypic and genotypic characterization of Chinese children diagnosed with tuberous sclerosis complex

We investigated the clinical phenotypes and genetic mutations in Chinese children diagnosed with tuberous sclerosis complex (TSC). Sequencing of TSC1 and TSC2 genes was performed in 117 children with TSC and their parents. Association of TSC gene mutations with clinical manifestations was investigated. All gene mutations were heterozygous including in 16 patients (13.7%) with mutations in TSC1 gene and 101 patients (86.3%) with mutations in TSC2 gene. Among the 16 patients with TSC1 gene mutations, 15 different types of mutations were found, which included 5 novel mutations; all patients had skin manifestations and epilepsy. Among the 101 patients with TSC2 mutations, 85 different types of mutations were found, which included 25 novel mutations; 97 patients (96.0%) had skin manifestations; 97 (96.0%) had epilepsy; 74 (73.3%) had intellectual disability and 25 patients (24.8%) were autistic. The clinical phenotype of the 14 children with familial TSC was more severe than that of their parents.

[Investigation on immunization program coverage rate and its safety in children with tuberous sclerosis]

Objective: To investigate the status of immunization of National Immunization Program (NIP) and its adverse reaction rate in children with tuberous sclerosis. Method: Questionnaire survey was adopted to identify the vaccination coverage and its adverse events; 72 cases of children with tuberous sclerosis and 78 normal controls (healthy children completing age-appropriate NIP) admitted to Chinese People's Liberation Army General Hospital from December 2014 to November 2015 were involved into this study. Result: The age-appropriate NIP coverage rate of tuberous sclerosis was 36%(26/72). The coverage rate of bacillus calmette-guerin (BCG), hepatitis B vaccine 1^st to 3^rd doses (HepB1-3), oral poliovaccine 1^st dose (OPV1), diphtheria, pertussis and tetanus 1^st dose (DPT1), DPT1-3, meningococcal polysaccharide vaccine group A (MPVA), measles amd rubella vaccine/measles vaccine 1^st dose (MRV/MCV1), and Japanese encephalitis vaccine 1^st dose (JEV1) were 100%(72 cases), 75%(51 cases), 97%(66 cases), 91%(62 cases), 82%(56 cases), 66%(45 cases), 69%(42 cases), and 61%(37 cases) respectively. The reasons why the children did not complete the vaccination plan were that parents were concerned about vaccination-induced seizures or seizures had not been controlled. Among 72 children with TSC, the rate of adverse events or suspected adverse events after vaccination was 17% (12 cases), which was higher than the normal control children (2 cases, 3%) (χ²=8.799, P<0.05). The main adverse events were seizure events, which accounted for 92%(11 cases). Conclusion: The age-appropriate NIP coverage rate among children with tuberous sclerosis is low. The high incidence of adverse events may be associated with a fact that there are some nervous system abnormalities in cases with tuberous sclerosis. TSC children vaccination is relatively safe, with no serious adverse events.

[Rapamycin in the treatment of cardiac rhabdomyoma associated with tuberous sclerosis complex]

OBJECTIVE

To assess the efficacy and safety of mammalian target of rapamycin (mTOR) inhibitor rapamycin in treatment of children with cardiac rhabdomyoma, associated with tuberous sclerosis complex (TSC).

METHOD

The clinical data of children with cardiac rhabdomyomas, who had received a diagnosis of TSC previously, were collected between September 2011 and November 2015 from Pediatric Department of the People's Liberation Army General Hospital.Patients in line with the inclusion criteria received long-term treatment with sirolimus.The starting doses of sirolimus was 1 mg/ (m(2)·d), and the plasma concentration was maintained at 5-10 μg/L.The size and number of cardiac rhabdomyomas were analyzed after treatment with rapamycin, and the efficacy and safety were assessed. The Wilcoxon test was used to analyze data.

RESULT

All the 51 children met the inclusion and exclusion criteria, including 30 males and 21 females.The median age for rapamycin treatment was 15.0 months (7.0-35.0 months). Tumors disappeared in 26 (51%) children, decreased by more than 50%(including 50%) in 15 (29%) children, decreased by less than 50% in 5 (12%) children, and had no change or progressed in 4 (8%) children.The number of tumors decreased by 77(72%). The median maximum diameter of tumor was 8.7 (5.9-11.3) mm before treatment, 0.0 (0.0-4.0) mm after treatment, and the median decrease of tumor size were 6.7 (3.9-10.0) mm (Z=-8.817, P<0.01). The median disappearance time was 3.26 (2.92-5.37) months.Among different age groups, after treatment by rapamycin, the rate of tumor's disappearance was 50% (12/24) in 0-1 years group.Tumors disappeared in 10 of 16 patients in >1-3 years group and in 4 of 11 patients in >3 years group.The rate of tumor's disappearance was the highest after 3 months of treatment as compared with 6 and 12 months of treatment.Ten children had adverse event that was related to rapamycin.Canker sore was reported in one child and dyslipidemia was reported in 9 children.

CONCLUSION

Rapamycin is efficacious and well tolerate in treatment of cardiac rhabdomyomas associate with TSC, and lead to a reduction in tumor size and number, in addition, significantly shorten the duration of cardiac rhabdomyoma.

Inflammation and cancer: till death tears them apart

Advances in biotechnology have enabled the collection of an immeasurable amount of information from genomic, transcriptomic, metabolomic and proteomic studies of tumours within their microenvironments. The dissection of cytokine and chemokine networks has provided new clues to the interactions between cancer cells and their surrounding inflammatory landscape. To bridge the gap between chronic inflammation and cancer, dynamic participants in the tumour microenvironment have been identified, including tumour-associated macrophages (TAMs) and regulatory T cells (Tregs). Both of these cell types are notable for their ability to cause immunosuppressive conditions and support the evasion of tumour immune surveillance. It is clear now that the tumour-promoting inflammatory environment has to be included as one of the major cancer hallmarks. This review explores the recent advances in the understanding of cancer-related inflammation and how this is being applied to comparative oncology studies in humans and domestic species, such as the dog.

Feline mammary carcinoma stem cells are tumorigenic, radioresistant, chemoresistant and defective in activation of the ATM/p53 DNA damage pathway

Cancer stem cells were identified in a feline mammary carcinoma cell line by demonstrating expression of CD133 and utilising the tumour sphere assay. A population of cells was identified that had an invasive, mesenchymal phenotype, expressed markers of pluripotency and enhanced tumour formation in the NOD-SCID mouse and chick embryo models. This population of feline mammary carcinoma stem cells was resistant to chemotherapy and radiation, possibly due to aberrant activation of the ATM/p53 DNA damage pathway. Epithelial–mesenchymal transition was a feature of the invasive phenotype. These data demonstrate that cancer stem cells are a feature of mammary cancer in cats.

Epithelial-mesenchymal transition as a fundamental mechanism underlying the cancer phenotype

Epithelial-mesenchymal transition (EMT) is a complex process involved in embryonic development, wound healing and carcinogenesis. During this process, epithelial cells lose their defining characteristics and acquire mesenchymal properties: loss of cell-cell adhesion; increased motility and invasiveness; resistance to apoptosis and changes in cellular morphology. EMT has been implicated as a driver of metastasis and tumour invasion, as this process allows cells to detach from their niche and migrate through blood and lymphatic vessels to invade different organs. This transition involves a diverse range of transcription factors, including Twist, Snail and ZEB1, and downstream transcriptional targets, including E-cadherin, β-catenin, fibronectin and vimentin. Recent evidence indicates that cancer stem cells are required for metastatic tumours to become established at a distant site, and that cancer cells undergoing EMT may develop stem-cell characteristics as well as increased invasive potential. The role of EMT in cancer biology is newly emerging in the human field, and to date very little has been done in veterinary medicine. EMT may therefore be an important molecular determinant of tumour metastasis, and further understanding of this process may lead to novel drug targets to be exploited in both veterinary and human medicine.

Identification of tumour initiating cells in feline head and neck squamous cell carcinoma and evidence for gefitinib induced epithelial to mesenchymal transition

Feline oral squamous cell carcinoma is considered a highly invasive cancer that carries a high level of morbidity. Despite aggressive surgery, patients often succumb to disease, the tumour having inherent insensitivity to radiation and chemotherapy. In this study we sought to identify cells within the feline SCC1 line that have stem cell properties, including inherent resistance mechanisms. When feline cells were subjected to harsh growth conditions, they formed sphere colonies consistent with a stem cell phenotype. Utilising CD133, we were able to identify a small fraction of cells within the population that had enhanced sphere-forming ability, reduced sensitivity to radiation and conventional chemotherapy and demonstrated resistance to the EGFR-targeting drug, gefitinib. In addition, long-term culture of feline SSC1 cells in gefitinib caused a change in cell morphology and gene expression reminiscent of an epithelial to mesenchymal transition. Taken together, these results suggest that feline SCC may be driven by small subset of cancer stem cells.

Applying Independent Component Analysis on ECG Cancellation Technique for the Surface Recording of Trunk Electromyography

Surface electromyography (sEMG) recorded from the trunk area may reflect underlying muscular function, and is the current standard for in vivo functional examination. However, sEMG of this area, including the low back musculature, usually encounters substantial interference from strong cardiac signals. It is therefore imperative to remove electrocardiogram (ECG) interference from sEMG data. This paper discusses a denoise method using independent component analysis (ICA) and a high-pass filter to effectively suppress the interference of ECG in sEMG recorded from trunk muscles. The performance of this technique was evaluated with simulation experiments. To compare the outcome of the ICA and filtering technique to the original sEMG signal, correlation coefficients in both time-domain waveform and frequency spectrum were computed. In addition, different filter bands were evaluated. The ICA ECG cancellation with a 30Hz high-pass filter showed higher mean correlation coefficients in the time domain (0.97&#177;0.08) and in the frequency spectrum (0.99&#177;0.06) than any other techniques. This suggests that the ICA ECG cancellation technique with a 30 Hz high-pass filter would be the most appropriate method to extract useful sEMG signals from trunk muscles.

Automated leakage current measurement for medical equipment safety

Electrical safety is always an important item of medical equipment in hospital. With the development of clinical engineering, the electric safety testing has become a routine procedure for the unit of clinical engineering in hospital. Among the parameters of safety standard of medical equipment, the leakage currents are more important than others. This study is aimed in the measurement of different leakage currents. An intelligent and digital tester was applied to test the safety quality of medical instrument automatically. This tester was based on a chip-computer (INTER 8031). This tester was designed to be able to set up as normal status or single failure status for automatic test by electric relays. All the results, free from manual errors, are displayed by means of a LCD unit and printed by a micro-printer. The output of high accuracy is also an advantage of this instrument, which is based on a precise signal detection electrical circuit and adaptive filter. This tester can be easily used for the clinic unit follow the standard of China GB9706 as well as IEC standard 601 and UL2601.

Current density distribution under surface electrode on posterior tibial nerve electrical stimulation

Electrical stimulation on the posterior tibial nerve is commonly used in the measurement of somatosensory evoked potential (SEP). To improve the efficiency of stimulation, the potential field and current density distributions under the surface electrodes were simulated with a three layer theoretical model. The mirror method was used to analyze the potential field of point charge. Integration of the field and the stimulus area provide the potential field for one surface electric pole. Potential field distribution of the bipolar electrodes was calculated by superimposition of two unipolar fields. Finally, the current density distribution was calculated by Laplace equation. An analytical solution of the potential field was obtained; thereafter the numerical solution of the current density distribution was calculated. The potential field and current density distribution were simulated by 2-D plot. From the model and simulation, the potential and current density distributions were not found to be evenly distributed under transcutaneous stimulation electrode and the maximum current density is located under the poles. The result suggests that bipolar stimulator should be applied axially along the stimulated nerve course.

Ultrashort-pulse generation from high-power diode arrays by using intracavity optical nonlinearities

A 40-stripe diode array was actively mode locked in an external cavity containing a single-mode optical fiber and a six-prism sequence to provide self-phase-modulation and tunable dispersion compensation. By making the total cavity group-velocity dispersion strongly negative, a solitonlike pulse-shaping process could be created. Pulses as short as 650 fs with a time-bandwidth product of 0.47 were generated. This study extends new techniques developed for mode locking solid-state lasers to diode-based systems.

Optical square-wave generation in a diode-laser array

We describe a new mechanism for passive generation of rapid-rise-time, high-bandwidth optical square waves based on directional switching. By using a diode-laser array in an external optical cavity, square-wave optical signals as fast as 250 MHz with detector-limited rise times of less than 200 ps are generated.

Two-stage injection locking of high-power semiconductor arrays

A new multistage diode-array injection-locking technique is demonstrated. This approach permits higher power extraction or higher overall gain to be achieved than possible with single-stage designs. Using two antireflectioncoated 40-stripe multiple-quantum-well diode arrays, we characterize the amplifier small-signal and saturated gain performance. More than 500 mWof power is achieved with single frequency and narrow linewidth in a nearly diffraction-limited far-field lobe. With small-signal inputs, an overall gain of 25 dB with 290-mW locked output is obtained.