Expression pattern of Ngn3 in dairy goat testis and its function in promoting meiosis by upregulating Stra8

OBJECTIVES

Ngn3 is a typical transcription factor and marker of differentiating spermatogonial stem cells (SSCs) in mouse, belonging to the basic helix-loop-helix (bHLH) family. Its gene is specifically expressed in A type spermatogonia in mouse testis, thus plays a critical role in controlling differentiation of SSCs. However, roles of Ngn3 and its protein in dairy goat testis remain unknown.

MATERIALS AND METHODS

Testis development and expression patterns of Ngn3 were analysed by immunofluorescence and quantitative reverse transcription-polymerase chain reaction (QRT-PCR) in the dairy goat. Furthermore, effects of its overexpression on male germline stem cells (mGSCs) were evaluated by QRT-PCR, immunofluorescence, luciferase reporter assay and western blotting.

RESULTS

Revealed that Ngn3 was expressed more highly during puberty and in the adult than in testis of other ages. Overexpression of Ngn3 promoted expression of meiosis-related gene Stra8 and stem-cell differentiation marker CD117, but suppressed expression of Plzf, a classical marker of SSCs. Furthermore, Ngn3 did not promote expression of Stra8 directly as shown in transcription and translation levels detected by luciferase reporter assay and western blotting.

CONCLUSIONS

Taken together, these results suggest that Ngn3 plays an important role in spermatogenesis and that overexpression of Ngn3 can promote meiosis in testis of the dairy goat.

Research potential of multi-lineage chicken amniotic mesenchymal stem cells

Amniotic mesenchymal stem cells (AMSCs) express octamer binding transcription factor 4 (Oct-4), which is necessary for maintaining the undifferentiated state of pluripotent stem cells. AMSCs also express CD29, CD44 and vimentin, which are specific markers of mesenchymal cells. We studied the biological characteristics and potential for cell therapy of AMSCs derived from 8-day-old chicken embryos. We induced the AMSCs to differentiate into adipocytes, osteoblasts and myocardial cells and used immunofluorescence, reverse transcription-polymerase chain reaction (RT-PCR) assays to detect the expressions of specific markers of AMSCs and differentiated cells. To assess the differentiation capacity of AMSCs, passage four cells were induced to differentiate into adipocytes, osteoblasts and myocardial cells. These results suggested that AMSCs isolated from chicken embryos exhibited the characteristics of multipotent stem cells. AMSCs, therefore, may be potential candidates for cellular transplantation therapy and tissue engineering.

Ricci Flow-based Spherical Parameterization and Surface Registration

This paper presents an improved Euclidean Ricci flow method for spherical parameterization. We subsequently invent a scale space processing built upon Ricci energy to extract robust surface features for accurate surface registration. Since our method is based on the proposed Euclidean Ricci flow, it inherits the properties of Ricci flow such as conformality, robustness and intrinsicalness, facilitating efficient and effective surface mapping. Compared with other surface registration methods using curvature or sulci pattern, our method demonstrates a significant improvement for surface registration. In addition, Ricci energy can capture local differences for surface analysis as shown in the experiments and applications.

Location and characterization of female germline stem cells (FGSCs) in juvenile porcine ovary

OBJECTIVES

Existence of germline stem cells (GSCs) in juvenile mammalian female ovaries has been drastically debated recently since reports that adult mouse ovaries still have mitotically active germ cells have been proposed. In addition, definitive location of such female germline stem cells (FGSCs) had not been demonstrated.

MATERIALS AND METHODS

We segregated porcine FGSCs mechanically from ovary cortex, and tested our hypotheses by utilizing immunofluorescent staining, qRT-PCR and western blotting.

RESULTS

We attached emphasis to unambiguous location of FGSCs, which settle simultaneously in the theca. Dissected cells from porcine thecal layers maintained similar characteristics to mouse FGSCs and ESCs over 4-months in vitro culture.

CONCLUSION

These results may provide a new resource for the study of oogenesis and therapy for ovarian sterility.

The neuroprotective role and mechanisms of TERT in neurons with oxygen-glucose deprivation

Telomerase reverse transcriptase (TERT) is reported to protect neurons from apoptosis induced by various stresses including hypoxia-ischemia (HI). However, the mechanisms by which TERT exerts its anti-apoptotic role in neurons with HI injury remain unclear. In this study, we examined the protective role and explored the possible mechanisms of TERT in neurons with HI injury in vitro. Primary cultured neurons were exposed to oxygen and glucose deprivation (OGD) for 3h followed by reperfusion to mimic HI injury in vivo. Plasmids containing TERT antisense, sense nucleotides, or mock were transduced into neurons at 48h before OGD. Expression and distribution of TERT were measured by immunofluorescence labeling and western blot. The expression of cleaved caspase 3 (CC3), Bcl-2 and Bax were detected by western blot. Neuronal apoptosis was measured with terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL). The mitochondrial reactive oxygen species (ROS) were measured by MitoSOX Red staining. Fluorescent probe JC-1 was used to measure the mitochondrial membrane potential (ΔΨm). We found that TERT expression increased at 8h and peaked at 24h in neurons after OGD. CC3 expression and neuronal apoptosis were induced and peaked at 24h after OGD. TERT inhibition significantly increased CC3 expression and neuronal apoptosis after OGD treatment. Additionally, TERT inhibition decreased the expression ratio of Bcl-2/Bax, and enhanced ROS production and ΔΨm dissipation after OGD. These data suggest that TERT plays a neuroprotective role via anti-apoptosis in neurons after OGD. The underlying mechanisms may be associated with regulating Bcl-2/Bax expression ratio, attenuating ROS generation, and increasing mitochondrial membrane potential.

miR-34c works downstream of p53 leading to dairy goat male germline stem-cell (mGSCs) apoptosis

OBJECTIVES

Recent lines of evidence have indicated that miR-34c can play important roles in regulation of the cell cycle, cell senescence and apoptosis of mouse and human tumour cells, spermatogenesis, and male germ-cell apoptosis. However, there is little information on the effects of miR-34c on proliferation and apoptosis of livestock male germ cells. The dairy goat is a convenient domestic species for biological investigation and application. The purpose of this study was to investigate the effects of miR-34c on apoptosis and proliferation of dairy goat male germline stem cells (mGSCs), as well as to determine the relationship between p53 and miR-34c in this species.

MATERIALS AND METHODS

Morphological observation, miRNA in situ hybridisation (ISH), bromodeoxyuridine staining, flow cytometry, quantitative-RT-PCR (Q-RT-PCR) and western blotting were utilized to ascertain apoptosis and proliferation of mGSCs, through transfection of miR-34c mimics (miR-34c), miR-34c inhibitor (anti-miR-34c), miR-34c mimics and inhibitors co-transfected (mixture) compared to control groups.

RESULTS

Results manifested that miR-34c over-expression promoted mGSCs apoptosis and suppressed their proliferation. Simultaneously, a variety of apoptosis-related gene expression was increased while some proliferation-related genes were downregulated. Accordingly, miR-34c promoted apoptosis in mGSCs and reduced their proliferation; moreover, expression of miR-34c was p53-dependent.

CONCLUSIONS

This study is the first to provide a model for study of miRNAs and mechanisms of proliferation and apoptosis in male dairy goat germ cells.

Role of magnetic resonance imaging in the detection of local prostate cancer recurrence after external beam radiotherapy and radical prostatectomy

AIMS

To carry out a meta-analysis to assess the effectiveness of magnetic resonance imaging (MRI) during the follow-up of patients with prostate cancer after undergoing external beam radiotherapy (EBRT) or radical prostatectomy.

MATERIALS AND METHODS

MEDLINE, EMBASE and other databases were searched for relevant original articles published from January 1995 to October 2011. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. Pooled estimation and subgroup analysis data were obtained by statistical analysis.

RESULTS

Fourteen of 768 initially identified studies were included in the meta-analysis. Seven studies examining patient after radical prostatectomy had a pooled sensitivity and specificity on the patient level of 82% (95% confidence interval 78-86%) and 87% (95% confidence interval 81-92%), respectively. In the subgroup analysis, compared with T2-weighted imaging (T2WI), dynamic contrast-enhanced (DCE) MRI showed higher pooled sensitivity (85%, 95% confidence interval 78-90%) and specificity (95%, 95% confidence interval 88-99%). DCE MRI combined with magnetic resonance spectroscopic imaging (1H-MRSI) had the highest pooled sensitivity (92%, 95% confidence interval 83-97%). Nine studies examining men after EBRT had a pooled sensitivity and specificity on the patient level of 82% (95% confidence interval 75-88%) and 74% (95% confidence interval 64-82%), respectively. Compared with T2WI, DCE MRI showed higher pooled sensitivity (90%, 95% confidence interval 77-97%) and specificity (81%, 95% confidence interval 64-93%). DCE combined with 1H-MRSI had the highest pooled specificity (90%, 95% confidence interval 56-100%). The pooled sensitivity and specificity on sextant analysis was 58% (95% confidence interval 53-64%) and 85% (95% confidence interval 82-88%), respectively. DCE MRI showed the highest pooled sensitivity: 71% (95% confidence interval 60-80%).

CONCLUSION

A limited number of small studies suggest that MRI can accurately detect local recurrences after EBRT and radical prostatectomy. DCE MRI is particularly accurate. The addition of MRSI to DCE MRI can significantly improve the diagnostic accuracy of local prostate cancer recurrence. The eventual role of 1H-MRSI alone remains controversial and needs to be defined further.

Surface-emission studies in a high-field RF gun based on measurements of field emission and Schottky-enabled photoemission

We report on investigations into the fundamental surface emission parameters, the geometric field enhancement factor (β) and the work function (φ), by making both field emission and Schottky-enabled photoemission measurements. The measurements were performed on a copper surface in the Tsinghua University S-band RF gun in two separate experiments. Fitting our data to the models for each experiment indicate that the traditionally assumed high value of β(≈50-500) does not provide a plausible explanation of the data, but incorporating a low value of φ at some sites does. In addition, direct measurements of the surface conducted after the experiment show that β is on the order of a few, consistent with our understanding of the electron emission measurements. Thus we conclude that the dominant source of electron emission in high gradient RF cavities is due to low φ sites, as opposed to the conventionally assumed high β sites. The origin of low φ at these sites is unclear and should be the subject of further investigation.

GSK3 inhibitor-BIO regulates proliferation of female germline stem cells from the postnatal mouse ovary

OBJECTIVE

It is widely believed that in most female mammalian neonates, all germ cells enter meiosis to form the primary oocyte at the end of foetal development, and as a result, the postnatal mammalian ovary harbours only a limited supply of oocytes that cannot be regenerated. However, this idea has been challenged by the discovery of the existence of female germline stem cells (FGSCs) in postnatal mammalian ovaries.

MATERIALS AND METHODS

We have isolated ovarian GSCs from neonatal and adult mouse ovaries and expanded them in the same culture conditions as embryonic stem cells (ESCs).

RESULTS

LIF and BIO were beneficial for formation of FGSC colonies. BIO promoted proliferation of FGSCs through activation of β-catenin and up-regulation of E-cadherin. The FGSCs formed compact round colonies with unclear borders, maintained ESC characteristics and alkaline phosphatase (AP) activity, expressing germ-cell markers-Vasa, and stem-cell markers: Oct4, Klf4, C-myc, Nanog, CD49f, Sox2, CD133, SSEA1 and SSEA4. These cells had the ability to form embryoid bodies (EBs), which expressed specific markers for all three germ layers. Then we induced EBs to differentiate into neurons, cardiomyocytes, pancreatic cells and germ cells, which showed the expression of specific markers, β-III-tubulin, cardiac a-actin, Pdx1 and Zps respectively.

DISCUSSION AND CONCLUSION

This study reveals the existence of FGSCs in postnatal mouse ovary with multipotent characteristics. BIO played an important role in regulation of proliferation and maintenance of the FGSCs. This could help provide a better understanding of causes of ovarian infertility, prevention and potential treatment of infertility.

Differential host susceptibility to Batrachochytrium dendrobatidis, an emerging amphibian pathogen

The amphibian fungal pathogen Batrachochytrium dendrobatidis (Bd) has received considerable attention due to its role in amphibian population declines worldwide. Although many amphibian species appear to be affected by Bd, there is little information on species-specific differences in susceptibility to this pathogen. We used a comparative experimental approach to examine Bd susceptibility in 6 amphibian species from the United States. We exposed postmetamorphic animals to Bd for 30 days and monitored mortality, feeding rates, and infection levels. In all species tested, Bd-exposed animals had higher rates of mortality than unexposed (control) animals. However, we found differences in mortality rates among species even though the amount of Bd detected on the different species' bodies did not differ. Of the species tested, southern toads (Anaxyrus terrestris) and wood frogs (Lithobates sylvaticus) had the highest rates of Bd-related mortality. Within species, we detected lower levels of Bd on individuals that survived longer and found that the relationship between body size and infection levels differed among species. Our results indicate that, even under identical conditions, amphibian species differ in susceptibility to Bd. This study represents a step toward identifying and understanding species variation in disease susceptibility, which can be used to optimize conservation strategies.

Activity of antimicrobial peptide mimetics in the oral cavity: I. Activity against biofilms of Candida albicans

Naturally occurring antimicrobial peptides hold promise as therapeutic agents against oral pathogens such as Candida albicans but numerous difficulties have slowed their development. Synthetic, non-peptidic analogs that mimic the properties of these peptides have many advantages and exhibit potent, selective antimicrobial activity. Several series of mimetics (with molecular weight < 1000) were developed and screened against oral Candida strains as a proof-of-principle for their antifungal properties. One phenylalkyne and several arylamide compounds with reduced mammalian cytotoxicities were found to be active against C. albicans. These compounds demonstrated rapid fungicidal activity in liquid culture even in the presence of saliva, and demonstrated synergy with standard antifungal agents. When assayed against biofilms grown on denture acrylic, the compounds exhibited potent fungicidal activity as measured by metabolic and fluorescent viability assays. Repeated passages in sub-minimum inhibitory concentration levels did not lead to resistant Candida, in contrast to fluconazole. Our results demonstrate the proof-of principle for the use of these compounds as anti-Candida agents, and their further testing is warranted as novel anti-Candida therapies.

Activity of antimicrobial peptide mimetics in the oral cavity: II. Activity against periopathogenic biofilms and anti-inflammatory activity

Whereas periodontal disease is ultimately of bacterial etiology, from multispecies biofilms of gram-negative anaerobic microorganisms, much of the deleterious effects are caused by the resultant epithelial inflammatory response. Hence, development of a treatment that combines anti-biofilm antibiotic activity with anti-inflammatory activity would be of great utility. Antimicrobial peptides (AMPs) such as defensins are naturally occurring peptides that exhibit broad-spectrum activity as well as a variety of immunomodulatory activities. Furthermore, bacteria do not readily develop resistance to these agents. However, clinical studies have suggested that they do not represent optimal candidates for exogenous therapeutic agents. Small-molecule mimetics of these AMPs exhibit similar activities to the parent peptides, in addition to having low toxicity, high stability and low cost. To determine whether AMP mimetics have the potential for treatment of periodontal disease, we examined the activity of one mimetic, mPE, against biofilm cultures of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Metabolic assays as well as culture and biomass measurement assays demonstrated that mPE exhibits potent activity against biofilm cultures of both species. Furthermore, as little as 2 μg ml(-1) mPE was sufficient to inhibit interleukin-1β-induced secretion of interleukin-8 in both gingival epithelial cells and THP-1 cells. This anti-inflammatory activity is associated with a reduction in activation of nuclear factor-κB, suggesting that mPE can act both as an anti-biofilm agent in an anaerobic environment and as an anti-inflammatory agent in infected tissues.

Characterization of immortalized mesenchymal stem cells derived from foetal porcine pancreas

Islet replacement therapy is limited by shortage of donor islet cells. Usage of islet cells derived from porcine pancreatic stem cells (PSCs) is currently viewed as the most promising alternative for human islet transplantation. However, PSCs are rare and have a finite proliferative lifespan. In this study, we isolated and established an immortalized mesenchymal stem cell (MSC) line derived from foetal porcine pancreas, by transfecting human telomerase reverse transcriptase (hTERT) and called these immortalized pancreatic mesenchymal stem cells (iPMSCs). The iPMSCs have been cultured for more than 80 passages and have capacity to differentiate into neurons, cardiomyocytes, germ cells and islet-like cells, analysed by morphology, RT-PCR, western blotting, immunofluorescence, immunocytochemistry and transplantation assay. Islets derived from iPMSCs reversed hyperglycaemia in streptozotocin-induced diabetic mice and secreted insulin and C-peptide in vitro. These results demonstrated that iPMSCs might provide unlimited resources for islet replacement therapy and models for functional cell differentiation.

Uncemented computer-assisted design-computer-assisted manufacture femoral components in revision total hip replacement

We prospectively evaluated the long-term outcome of 158 consecutive patients who underwent revision total hip replacement using uncemented computer-assisted design-computer-assisted manufacture femoral components. There were 97 men and 61 women. Their mean age was 63.1 years (34.6 to 85.9). The mean follow-up was 10.8 years (10 to 12).

The mean Oxford, Harris and Western Ontario and McMaster hip scores improved from 41.1, 44.2 and 52.4 pre-operatively to 18.2, 89.3 and 12.3, respectively (p < 0.0001, for each). Six patients required further surgery. The overall survival of the femoral component was 97% (95% confidence interval 94.5 to 99.7). These results are comparable to those of previously published reports for revision total hip replacement using either cemented or uncemented components.

Uncemented custom computer-assisted design and manufacture of hydroxyapatite-coated femoral components

We present the 10- to 17-year results of 112 computer-assisted design computer-assisted manufacture femoral components. The total hip replacements were performed between 1992 and 1998 in 111 patients, comprising 53 men and 58 women. Their mean age was 46.2 years (24.6 to 62.2) with a mean follow-up of 13 years (10 to 17). The mean Harris Hip Score improved from 42.4 (7 to 99) to 90.3 (38 to 100), the mean Oxford Hip Score from 43.1 (12 to 59) to 18.2 (12 to 51) and the mean Western Ontario MacMasters University Osteoarthritis Index score from 57.0 (7 to 96) to 11.9 (0 to 85). There was one revision due to failure of the acetabular component but no failures of the femoral component. There were no revisions for aseptic loosening. The worst-case survival in this cohort of custom femoral components at 13.2 years follow-up was 98.2% (95% confidence interval 95 to 99). Overall survival of this series of total hip replacements was 97.3% (95% confidence interval 95 to 99).

These results are comparable with the best medium- to long-term results for femoral components used in primary total hip replacement with any means of fixation.