Development a survival prediction model for patients with Paget disease of the breast based on the SEER database

Background:We explored the risk factors that affect the prognosis of patients with Paget disease of the breast(PD)and constructed a survival prediction model.Methods:The data of PD patients from 2004 to 2014 were collected through the SEER database.The factors affecting the prognosis of PD patients were analysed by a single factor,and the prediction model of the independent risk factor transformation model diagram that affected their 1-,3-,and 5-year survival rates was screened by multivariate Cox proportional hazard regression analysis coefficients.The consistency index was used to evaluate its predictive value,and its predictive performance was tested by the 1000 bootstrap method.Then,the calibration curve was used to verify the predictive performance of the model,and the receiver operating characteristic curve and decision curve analysis were used to assess the sensitivity and practicability of the model compared to the American Cancer Commission staging(AJCC)staging system.Results:The consistency index of the model was 0.795(95%confidence interval 0.773–0.818).The calibration curve shows good consistency,while the receiver operating characteristic curve shows the sensitivity of the model to predict the survival rate of PD at 1,3,and 5 years.Decision curve analysis confirmed that the nomogram can predict the survival rate of PD patients at 1,3,and 5 years instead of the traditional AJCC system.Conclusion:Regarding the independent prognostic factors of age,marital status,AJCC classification,surgery,radiotherapy,chemotherapy and marital status conversion in PD patients,the nomogram established in sequence has higher accuracy and clinical value than the traditional AJCC system.

Synchronous and Asynchronous Blastomere Cleavage at Cryopreservation: Effect on Subsequent Embryo Survival, Pregnancy and Live Birth Rates

Capsule: Although embryos with synchronous blastomere cleavage showed higher post-thaw survival rates, pregnancy rates did not differ. Thus, embryos with all cleavage patterns may be safely cryopreserved. Objective: To compare post-thaw embryo survival, pregnancy and live birth rates of embryos with synchronous vs asynchronous blastomere cleavage in frozen embryo transfer (FET) cycles. Design: Retrospective study. Setting: University-affiliated IVF unit. Patients: One thousand and sixty FET cycles performed from 2004-2006. Interventions: Cycles were divided into 3 groups: 1: cycles in which only embryos with synchronous blastomere cleavage were frozen;2: cycles in which only embryos with asynchronous blastomere cleavage were frozen;3: cycles in which both embryos with synchronous and asynchronous blastomere cleavage were frozen. Clinical and laboratory data were recorded and analyzed. Main Outcome Measures: Post-thaw embryo survival, morphologic grading, pregnancy and live birth rates. Results: A total of 1863 embryos were analyzed. Synchronous embryos had higher blastomere survival rates and morphological grading at thawing. Pregnancy and birth rates did not differ among groups. In a multivariant logistic regression analysis, a number of transferred embryos and embryo morphological grading at thawing were the only parameters that affected pregnancy and live birth rates. Conclusions: Embryos with both synchronous and asynchronous blastomere cleavage can be selected by classical embryo grading and safely cryopreserved.

High in vitro survival rate of sheep in vitro produced blastocysts vitrified with a new method and device

Background:To advance the use of embryo vitrification in veterinary practice,we developed a system in which embryo vitrification,warming and dilution can be performed within a straw.Ovine in vitro produced embryos(IVEP)were vitrified at either early(EBs:n=74)or fully expanded blastocyst stage(FEBs:n=195),using a new device named"E.Vit",composed by a 0.25-m L straw with a 50-μm pore polycarbonate grid at one end.Embryos at each stage(EBs and FEBs)were vitrified by either Two-step(TS)or Multi-step(MS;6 different concentrations of vitrification solutions)protocol.Non-vitrified embryos(n=102)were maintained in in vitro culture as a control.Warming consisted of placing the straws directly into 1.5 m L tubes containing a TCM-199 solution with three decreasing concentrations of sucrose.Blastocyst re-expansion,embryo survival and hatching rate were evaluated at2,24 and 48 h post warming.The number of apoptotic cells was determined by TUNEL assay.Results:Blastocyst re-expansion(2 h)after warming was higher(P<0.05)in FEBs group,vitrified with the MS and TS methods(77.90%and 71.25%,respectively)compared with the EBs group(MS:59.38%and TS:48.50%,respectively).Survival rates of vitrified FEBs after 24 h IVC were higher(P<0.001)in both methods(MS and TS)than vitrified EBs(MS:56.25%;TS:42.42%)and was higher(P<0.05)in the MS method(94.19%)compared with those in TS(83.75%).After 48 h of culture the hatching rate for FEBs vitrified in MS system(91.86%)was similar to control(91.89%),but higher than FEB TS(77.5%)and EBs vitrified in MS(37.5%)and TS(33.33%).Number of apoptotic cells were higher in EBs,irrespective of the system used,compared to FEBs.The number of apoptotic cells in FEBs vitrified with MS was comparable to the control.Conclusions:A high survival rate of IVP embryos can be achieved by the new"E.Vit"device with hatching rates in vitro comparable with control fresh embryos.This method has the potential for use in direct embryo transfer in field conditions.

Nest survival rate of Reeves＇s pheasant(Syrmaticus reevesii) based on artificial nest experiments

To explore the nest survival rate of Reeves＇ s pheasant（Syrmaticus reevesii） and the nest-site factors that affect it, we conducted artificial nest experiments with reference to natural nests at Dongzhai National Nature Reserve（DNNR）, Henan Province and Pingjingguan, Hubei Province from April to June 2014 simulating the situation in its early and later breeding season. We also determined distance characteristics of the nest sites by Arc GIS 10.0. Nest survival models were constructed in Program MARK for data analysis. Results indicated that in the early breeding season, the apparent survival rate（ASR） in DNNR（52.4%） was significantly greater than that in Pingjingguan（13.5%）, and the ASR in the later breeding season in DNNR（26.7%） was not indistinctively correlated with Pingjingguan（3.2%）. The daily survival rate（DSR） in the later breeding season was 93.8% in DNNR and 92.0% in Pingjingguan, respectively. The DSRs were both negatively correlated with nest distance to forest edges and settlements. The DSR in Pingjingguan was positively correlated with nest distance to paths and negatively correlated with nest distance to water sources. However, the DSR in DNNR was negatively correlated with nest distance to paths but positively correlated with nest distance to water sources.

Gender difference in clinicopathologic features and survival of patients with hepatocellular carcinoma

AIM: To determine the influence of gender on the clinicopathologic characteristics and survival of patients with hepatocellular carcinoma (HCC). METHODS: A retrospective analysis of medical records was performed in 299 patients with HCC and their clinicopathologic features and survival were compared in relation to gender. RESULTS: There were 260 male (87%) and 39 female patients (13%),with a male-to-female ratio of 6.7:1.Female patients had lower mean serum bilirubin levels (P=0.03), lower proportion of alcohol abuse (P=0.002),smaller mean tumor size (P=0.02),more frequent nodular type but less frequent massive and diffuse types of HCC (P=0.01),were less advanced in Okuda's staging (P=0.04),and less frequently associated with venous invasion (P=0.03).The median survivals in females (14 too) were significantly longer than that of male patients (4 mo) (P=0.004,log-rank test). Multivariate analysis demonstrated that high serum alpha- fetoprotein levels,venous invasion,extrahepatic metastasis and lack of therapy were independent factors related to unfavorable prognosis.However,gender did not constitute a predictive variable associated with patient survival. CONCLUSION: Female patients tend to have higher survival rates than males.These differences were probably due to more favorable pathologic features of HCC at initial diagnosis and greater likelihood to undergo curative therapy in female patients.

Long-term survival after pancreaticoduodenectomy in patients with ductal adenocarcinoma of the pancreatic head

Background: Pancreatic ductal adenocarcinoma(PDAC) has the worst prognosis of all malignant tumors due to unavailable screening methods, late diagnosis with a low proportion of resectable tumors and resistance to systemic treatment. Complete tumor resection remains the cornerstone of modern multimodal strategies aiming at long-term survival. This study was performed to investigate the overall rate of long-term survival(LTS) and its contributing factors. Methods: This was a retrospective single-center analysis of consecutive patients undergoing pancreaticoduodenectomy(PD) for PDAC between 2007 and 2014 at the St. Josef Hospital, Ruhr University Bochum, Germany. Clinical and laboratory parameters were assessed and evaluated for prediction of LTS with Cox regression analysis. Results: The overall rate of LTS after PD for PDAC was 20.4%(34/167). Median survival was 24 months regardless of adjuvant treatment. Carbohydrate antigen 19-9 levels, tumor grade, lymph vessel invasion, perineural invasion and reduced general condition were significantly associated with LTS in univariate analysis( P<0.05). Serum levels of carbohydrate antigen 19-9, American Joint Committee on Cancer stage, tumor grade, abdominal pain, male, exocrine pancreatic insufficiency and duration of postoperative hospital stay were independent predictors of cancer survival in multivariable analysis. Conclusions: Cancer related characteristics are associated with LTS in multimodally treated patients after curative PDAC surgery.

Netrin-1 signaling pathway mechanisms in neurodegenerative diseases

Netrin-1 and its receptors play crucial roles in inducing axonal growth and neuronal migration during neuronal development.Their profound impacts then extend into adulthood to encompass the maintenance of neuronal survival and synaptic function.Increasing amounts of evidence highlight several key points:(1)Diminished Netrin-1 levels exacerbate pathological progression in animal models of Alzheimer’s disease and Parkinson’s disease,and potentially,similar alterations occur in humans.(2)Genetic mutations of Netrin-1 receptors increase an individuals’susceptibility to neurodegenerative disorders.(3)Therapeutic approaches targeting Netrin-1 and its receptors offer the benefits of enhancing memory and motor function.(4)Netrin-1 and its receptors show genetic and epigenetic alterations in a variety of cancers.These findings provide compelling evidence that Netrin-1 and its receptors are crucial targets in neurodegenerative diseases.Through a comprehensive review of Netrin-1 signaling pathways,our objective is to uncover potential therapeutic avenues for neurodegenerative disorders.

Prognostic significance and relationship of SMAD3 phosphoisoforms and VEGFR-1 in gastric cancer:A clinicopathological study

BACKGROUND The TGF-β/SMAD3 and VEGFR-1 signaling pathways play important roles in gastric cancer metastasis.SMAD3 phosphorylation is a crucial prognostic marker in gastric cancer.AIM To determine the prognostic value and relationship of SMAD3 phospho-isoforms and VEGFR-1 in gastric cancer.METHODS This was a single-center observational study which enrolled 98 gastric cancer patients and 82 adjacent normal gastric tissues from patients aged 32-84 years(median age 65)between July 2006 and April 2007.Patients were followed up until death or the study ended(median follow-up duration of 28.5 mo).The samples were used to generate tissue microarrays(TMAs)for immunohistochemical(IHC)staining.The expressions of TGF-β1,pSMAD3C(S423/425),pSMAD3L(S204),and VEGFR-1 in gastric cancer(GC)tumor tissue and normal tissue were measured by IHC staining using TMAs obtained from 98 GC patients.Prognosis and survival information of the patients was recorded by Outdo Biotech from May 2007 to July 2015.The relationship between TGF-β1,pSMAD3C(S423/425),pSMAD3L(S204),and VEGFR-1 protein expression levels was analyzed using Pearson's correlation coefficient.The relationship between protein expression levels and clinicopathological parameters was analyzed using the Chi-squared test.A survival curve was generated using the Kaplan-Meier survival analysis.RESULTS TGFβ-1 and VEGFR-1 expression was significantly upregulated in gastric cancer tissue compared to adjacent noncancerous tissue.The positive expression of phosphorylated isoforms of Smad3 varied depending on the phosphorylation site[pSMAD3C(S423/425):51.0%and pSMAD3L(S204):31.6%].High expression of pSMAD-3L(S204)was significantly correlated with larger tumors(P=0.038)and later N stages(P=0.035).Additionally,high expression of VEGFR-1 was closely correlated with tumor size(P=0.015)and pathological grading(P=0.013).High expression of both pSMAD3L(S204)and VEGFR-1 was associated with unfavorable outcomes in terms of overall survival(OS).Multivariate analysis indicated that high expression of pSMAD3L(S204)and VEGFR-1 were independent risk factors for prognosis in GC patients.VEGFR-1 protein expression was correlated with TGF-β1(r=0.220,P=0.029),pSMAD3C(S423/425)(r=0.302,P=0.002),and pSMAD3L(S204)(r=0.201,P=0.047),respectively.Simultaneous overexpression of pSMAD3L(S204)and VEGFR-1 was associated with poor OS in gastric cancer patients.CONCLUSION Co-upregulation of pSMAD3L(S204)and VEGFR-1 can serve as a predictive marker for poor gastric cancer prognosis,and pSMAD3L(204)may be involved in enhanced gastric cancer metastasis in a VEGFR-1-dependent manner.

LAPLACE TRANSFORM OF THE SURVIVAL PROBABILITY UNDER SPARRE ANDERSEN MODEL

In this paper a class of risk processes in which claims occur as a renewal process is studied. A clear expression for Laplace transform of the survival probability is well given when the claim amount distribution is Erlang distribution or mixed Erlang distribution. The expressions for moments of the time to ruin with the model above are given.

Survival mechanisms of <i>Mycobacterium avium</i>subspecies <i>paratuberculosis</i>within host species and in the environment—A review

Mycobacterium avium subsp. paratuberculosis causes chronic inflammation of the intestine known as Johne’s disease (JD) in domestic and wild ruminants including primates. MAP has also been associated with inflammatory bowel disease (IBD) so called Crohn’s disease (CD) of human beings, which is incurable even after surgery. By virtue of the pasteurization resistant power, high endemicity of the infection in animals continues to be the permanent source of infection to human population. High bio-burden of MAP in wide range of biotic (animal hosts including human beings) and abiotic environment in each and every country where it has been investigated, serves a reminder about the survival abilities of the MAP in diverse range of environmental conditions. Ability of the MAP to evade immune system of the host and the temporal events during infection of the macro-phages, is an area of major concern and research activities as the pattern of distribution are quiet different from those of other pathogenic intracellular organisms. Moreover, the organism can survive over a wide range of environmental conditions such as high and low environmental temperatures, pasteurization, low pH, and high salt concentration etc. This superior survival efficiency from environmental degradation and dormancy within host allows the pathogen to be available for causing disease and pathogenicity in animals and human beings, when conditions are favorable. Perusal of literature reveal that, despite the availability of whole genome sequence of MAP, a very little is known about the replication, persistence and survival mechanisms of this pathogen. Therefore, this review tries to address the survival mechanisms of Mycobacterium avium subspecies paratuberculosis in the different host species and adverse environmental conditions in order to allow designing of more rational diagnostic and control procedures.

A Comparison of Within-Subjects and Between-Subjects Designs in Studies with Discrete-Time Survival Outcomes

Crossover designs are well-known to have major advantages when comparing the effects of various non-curative treatments. We compare efficiencies of several crossover designs along with the Balaam’s design with that of a parallel group design pertaining to longitudinal studies where event time can only be measured in discrete time intervals. With equally sized sequences, the parallel group design results in the greater efficiency if the number of time periods is small. However, the crossover and Balaam’s designs tend to be more efficient as the study duration increases. The degree to which these designs add efficiency depends on the baseline hazard function and effect size. Additionally, we incorporate different cost considerations at the subject level when comparing the designs to determine the most cost-efficient design. Researchers might consider the crossover or Balaam’s design more efficient if the duration of the study is long enough, especially if the costs of applying the baseline treatment are higher.

Swaziland’s Survival

As Swaziland teeters on the edge of bankruptcy,its bailout package may be a litmus test for regional unity THE Kingdom of Swaziland is wilting under a crippling budget deficit that the International Monetary Fund(IMF) has pegged at 14.3 percent of the country’s GDP. This is within the same range as the Greek budgetary shortfalls ultimately giving precedence to the

Impact assessment of modified clay on embryo-larval stages of turbot Scophthalmus maximus L.

Using modified clay is one of the most promising methods for the mitigation of harmful algal blooms(HABs).However,the environmental impact of modified clay has become a subject of global concern.In this study,turbot(Scophthalmus maximus L.)embryos were used as a model to assess the effect of modified clay on this sensitive stage of fish development.Results show that the 24 and 48h LC 50(median lethal concentrations)of the modified clay were 1.70 and 1.65 g/L,and the safe concentration was 0.47 g/L,which is much higher than the concentration used to treat HAB.The modified clay did not affect significantly the hatchability of turbot embryos but when the concentration exceeded 0.50 g/L,the deformity rate of newly hatched larvae increased significantly.The total length,specific growth rate(SGR)and yolk sac absorption rate of larvae reached their peaks at 0.50 g/L and then gradually decreased as the concentration of modified clay increased.Therefore,a moderate amount of modified clay does not harm the survival and hatching of turbot embryos,or the growth and development of newly hatched larvae.

Creating New Germplasm by Distant Hybridization in Stone Fruits:Ⅱ-Embryo Rescue and Hybrid Identification Between Plum and Apricot

Embryo abortion stage and rescue system of hybrids were studied in the distant hybridizationbetween plum and apricot. Identification of the hybrids was also made. The resultsshowed: (1) Embryo abortion started from three weeks after pollination. (2) The germinationand growth of embryos were different at different growth stages, which could germinateand grow with PF value>0.5, but failed with PF value<0.5. In embryo rescue system ofhybrids, the best germination and differentiation medium was MS+6-BA 2mgL-1+IAA 0.3mgL-1,the rate of germination and differentiation reached up to 80%, bud induction andmultiplication medium was MS+6-BA 1.5mgL-1+IAA 0.3mgL-1, rooting medium was 1/2 MS+IAA0.8mgL-1. Some hybrids were transplanted into the field successfully. (3) Leaf shapeinvestigation and identification by S allele-specific PCR and RAPDs showed that thehybrids were true ones.

Activation of Uterine Smad3 Pathway Is Crucial for Embryo Implantation

Embryo implantation is a complicated physiological process tightly regulated by multiple biological molecules including growth factors.Transforming growth factor-betas(TGF-βs)and their most specific signal transduction factors,Smads,are expressed in the endometrium during the window of implantation.Recent researches indicated that Smad dependent TGF-β signaling may play an important role in the process of embryo implantation.In this study,we measured the expression of TGF-β1,TGF-β receptor type I(TpRI),Smad3 and p-Smad3 in the endometrium of mice and observed their elevation on day 4,5 and 6 of pseudopregnancy.Then we administrated a specific Smad3 inhibitor(Sis3)into the uterine cavity of mice on day 3 of pregnancy.The results showed a reduction in insulin-like growth factor-1(IGFBP-1)expression and the decreased number of implanted embryo after the administration.In addition,Sis3 was found to reduce the IGFBP-1 secretion in decidualized endometrial stromal cells.Taken all together,our findings demonstrated that TGF-β/Smad3 signaling is involved in the process of embryo implantation.

Total saponins of Panax ginseng effects on proliferation and differentiation of human embryonic neural stem cells and in a Parkinson's disease mouse model

BACKGROUND： Total saponins of Panax ginseng （TSPG） exhibits neuroprotection against Parkinson＇s disease in the substantia nigra. OBJECTIVE： To investigate the effects of TSPG on human embryonic neural stem cells （NSCs） proliferation and differentiation into dopaminergic neurons using in vitro studies, and to observe NSC differentiation in a mouse model of Parkinson＇s disease, as well as behavioral changes before and after transplantation. DESIGN, TIME AND SETTING： In vitro neural cell biology trial and in vivo randomized, controlled animal trial were performed at the Institute of Basic Medical Sciences, Chongqing Medical University between September 2004 and December 2007. MATERIALS： TSPG （purity 〉 95%） was isolated, extracted, and identified by Chongqing Academy of Chinese Materia Medica. Recombinant human basic fibroblast growth factor （bFGF） and recombinant human epidermal growth factor （EGF） were purchased from PeproTech, USA. A total of 25 C57/BL6J mice, aged 18-20 weeks were included. Twenty were used to establish a Parkinson＇s disease model with i.p. injection of MPTP （1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine） and TSPG alone or combined with interleukin-1 （IL-1）-treated NSCs prior to transplantation into the corpus striatum. The remaining five mice were pretreated for 3 days with TSPG prior to MPTP injection, serving as the TSPG prevention group. METHODS： Primary NSCs were isolated, cultured and purified from embryonic cerebral cortex. Immunocytochemistry was employed to detect specific antigen expression in the NSCs. In vitro experiment： （1） to induce proliferation, NSCs were treated with TSPG, EGF＋bFGF, or TSPG＋EGF＋bFGF, respectively; （2） to induce dopaminergic neuronal differentiation, NSCs were treated with TSPG, IL-1, or TSPG＋IL-1, respectively. MAIN OUTCOME MEASURES： In vitro experiment： the effects of TSPG on NSCs proliferation were evaluated with flow cytometry and MTT assay. Tyrosine hydroxylase expression was determined by immunocytochemistry assay to observe effects of TSPG on dopaminergic neuronal differentiation. In vivo experiment： differentiation of grafted NSCs in the mouse brain was determined by immunohistochemical staining. Behavioral changes were evaluated by spontaneous activity frequency, memory function, and score of paralysis agitans. RESULTS： （1） NSCs were cultured and passaged for more than three passages. Immunocytochemistry revealed positive nestin staining, as well as neurofilament protein and glial fibrillary acidic protein. （2） TSPG significantly increased NSC proliferation, in particular when combined with EGF and bFGF, which was twice as effective as FGF or bFGF alone. TSPG also induced dopaminergic differentiation in NSCs, in particular when TSPG was added together with IL-1, resulting in an effect five times greater than that of IL-1 alone. （3） At day 30 following transplantation, most NSCs in the TSPG prevention group differentiated into dopaminergic neurons, and the scores of paralysis agitans, spontaneous activity, and memory function were significantly increased compared with TSPG alone or TSPG＋IL-1 groups （P 〈 0.05）. CONCLUSION： TSPG stimulated NSC proliferation, in particular when combined with FGF and bFGF. TSPG significantly induced dopaminergic neuronal differentiation of NSCs, and the effect was greater when combined with IL-1. In addition, TSPG greatly improved behavior in the Parkinson＇s disease mouse model following NSC transplantation. Following NSC transplantation, TSPG pretreatment exhibited superior efficacy over either TSPG alone or TSPG in combination with IL-1, in terms of behavioral improvements in the Parkinson＇s disease mouse model.

Neuroprotective effects of human telomerase reverse transcriptase on beta-amyloid fragment 25-35-treated human embryonic cortical neurons

BACKGROUND： Numerous current studies have suggested that human telomerase reverse transcriptase （hTERT） gene has neuroprotective effects and can inhibit apoptosis induced by various cytotoxic stresses; however, the mechanism of action remains unknown. OBJECTIVE： To evaluate the neuroprotective effects and possible mechanism of action of hTERT gene transfection in human embryonic cortical neurons treated with beta-amyloid fragment 25-35 （AI325-35）. DESIGN, TIME AND SETTING： The randomized, controlled and molecular biological studies were performed at the Department of Anatomy and Brain Research, Zhongshan School of Medicine, Sun Yat-sen University, China, from September 2005 to June 2008. MATERIALS： AdEasy-1 Expression System was gifted by Professor Guoquan Gao from Sun Yat-Sen University, China. Human cortical neurons were derived from 12-20 week old aborted fetuses, obtained from the Guangzhou Maternal and Child Health Hospital, China. Mouse anti-Odk5 and mouse anti-p16 monoclonal antibodies （Lab Vision, USA）, and mouse anti-hTERT monoclonal antibody （Epitomics, USA）, were used in this study. METHODS： （1） Recombinant adenovirus vectors, encoding hTERT （Ad-hTERT） and green fluorescent protein （Ad-GFP）, were constructed using the AdEasy-1 Expression System. Human embryonic cortical neurons in the Ad-hTERT group were transfected with Ad-hTERT for 1-21 days. Likewise, human embryonic cortical neurons in the Ad-GFP group were transfected with Ad-GFP for 1-21 days. Human embryonic cortical neurons in the control group were cultured as normal. （2） Human embryonic cortical neurons in the Ad-hTERT group were treated with 10 pmol/L Aβ25-35 for 24 hours. Normal human embryonic cortical neurons treated with 10 pmol/Lβ25.35 for 24 hours served as a model group. Human embryonic cortical neurons in the Ad-GFP and control groups were not treated with Aβ25-35. MAIN OUTCOME MEASURES： Expression of hTERT in human embryonic cortical neurons was evaluated by immunocytochemical staining and Western blot assay. Telomerase activity was measured using a PCR-based telomeric repeat amplification protocol （TRAP） ELISA kit. Neural activity in human embryonic cortical neurons was examined by MTT assay; apoptosis was measured using TUNEL assay; and Cdk5 and p16 protein expressions were measured by Western blot. RESULTS： Expression of hTERT protein was significantly increased and peaked at day 3 post-transfection in the Ad-hTERT group. No hTERT expression was detected in the Ad-GFP and control groups. Telomerase activity was significantly greater in the Ad-hTERT group compared with the Ad-GFP and control groups （P 〈 0.01）. Compared with the control group, cell activity was significantly decreased （P 〈 0.05）, and cell apoptotic rate, Cdk5 and p16 expression were significantly increased （P 〈 0.01） in the model group. Compared with the model group, cell activity was increased in the Ad-hTERT group, and peaked at day 3 post-transfection （P 〈 0.05）. Neuroprotective effects also peaked at day 3 post-transfection; and the apoptotic rate, Cdk5 and p16 expression significantly decreased （P 〈 0.01）. CONCLUSION： Expression of hTERT in human embryonic cortical neurons can relieve Aβ25-35-induced neuronal apoptosis. The possible mechanism by which hTERT produces these neuroprotective effects may be associated with inhibition of Cdk5 and p16 expression.

Neurotrophic fragments as therapeutic alternatives to ameliorate brain aging

Aging is a global phenomenon and a complex biological process of all living beings that introduces various changes.During this physiological process,the brain is the most affected organ due to changes in its structural and chemical functions,such as changes in plasticity and decrease in the number,diameter,length,and branching of dendrites and dendritic spines.Likewise,it presents a great reduction in volume resulting from the contraction of the gray matter.Consequently,aging can affect not only cognitive functions,including learning and memory,but also the quality of life of older people.As a result of the phenomena,various molecules with notable neuroprotective capacity have been proposed,which provide a therapeutic alternative for people under conditions of aging or some neurodegenerative diseases.It is important to indicate that in recent years the use of molecules with neurotrophic activity has shown interesting results when evaluated in in vivo models.This review aims to describe the neurotrophic potential of molecules such as resveratrol(3,5,4′-trihydroxystilbene),neurotrophins(brain-derived neurotrophic factor),and neurotrophic-type compounds such as the terminal carboxyl domain of the heavy chain of tetanus toxin,cerebrolysin,neuropeptide-12,and rapamycin.Most of these molecules have been evaluated by our research group.Studies suggest that these molecules exert an important therapeutic potential,restoring brain function in aging conditions or models of neurodegenerative diseases.Hence,our interest is in describing the current scientific evidence that supports the therapeutic potential of these molecules with active neurotrophic.

Studies on Optimal Conditions of Two Freezing Methods for Preservation of Rabbit Embryos

Since the first report on the successful deep cryopreservation of mam-malian embryos in 1972,slow progressing cooling rate has been employ-ed in conventional embryos-freezing techniques;while more recent studieson freezing preimplantation embryos have focussed on the simplificationof cooling and thawing procedures and improvement of viability of embr-yos.Dimethylsulfoxide (DMSO)has been used as an effective cryoprotec-tant for freezing human and other mammalian embryos.It has been foundthat glycerol and other alcohols are effective to protect embryos fromcryoinjury