Inhibition of nociceptive responses after systemic administration of amidated kyotorphin

BACKGROUND AND PURPOSE

Kyotorphin (KTP; L-Tyr-L-Arg), an endogenous neuropeptide, is potently analgesic when delivered directly to the central nervous system. Its weak analgesic effects after systemic administration have been explained by inability to cross the blood-brain barrier (BBB) and detract from the possible clinical use of KTP as an analgesic. In this study, we aimed to increase the lipophilicity of KTP by amidation and to evaluate the analgesic efficacy of a new KTP derivative (KTP-amide - KTP-NH(2) ).

EXPERIMENTAL APPROACH

We synthesized KTP-NH(2) . This peptide was given systemically to assess its ability to cross the BBB. A wide range of pain models, including acute, sustained and chronic inflammatory and neuropathic pain, were used to characterize analgesic efficacies of KTP-NH(2) . Binding to opioid receptors and toxicity were also measured.

KEY RESULTS

KTP-NH(2) , unlike its precursor KTP, was lipophilic and highly analgesic following systemic administration in several acute and chronic pain models, without inducing toxic effects or affecting motor responses and blood pressure. Binding to opioid receptors was minimal. KTP-NH(2) inhibited nociceptive responses of spinal neurons. Its analgesic effects were prevented by intrathecal or i.p. administration of naloxone.

CONCLUSIONS AND IMPLICATIONS

Amidation allowed KTP to show good analgesic ability after systemic delivery in acute and chronic pain models. The indirect opioid-mediated actions of KTP-NH(2) may explain why this compound retained its analgesic effects although the usual side effects of opioids were absent, which is a desired feature in next-generation pain medications.

Tumor necrosis factor receptor-associated factor 6 (TRAF6) associates with huntingtin protein and promotes its atypical ubiquitination to enhance aggregate formation

Huntington disease (HD) is a neurodegenerative disorder caused by an expansion of polyglutamines in the first exon of huntingtin (HTT), which confers aggregation-promoting properties to amino-terminal fragments of the protein (N-HTT). Mutant N-HTT aggregates are enriched for ubiquitin and contain ubiquitin E3 ligases, thus suggesting a role for ubiquitination in aggregate formation. Here, we report that tumor necrosis factor receptor-associated factor 6 (TRAF6) binds to WT and polyQ-expanded N-HTT in vitro as well as to endogenous full-length proteins in mouse and human brain in vivo. Endogenous TRAF6 is recruited to cellular inclusions formed by mutant N-HTT. Transient overexpression of TRAF6 promotes WT and mutant N-HTT atypical ubiquitination with Lys⁶, Lys²⁷, and Lys²⁹ linkage formation. Both interaction and ubiquitination seem to be independent from polyQ length. In cultured cells, TRAF6 enhances mutant N-HTT aggregate formation, whereas it has no effect on WT N-HTT protein localization. Mutant N-HTT inclusions are enriched for ubiquitin staining only when TRAF6 and Lys⁶, Lys²⁷, and Lys²⁹ ubiquitin mutants are expressed. Finally, we show that TRAF6 is up-regulated in post-mortem brains from HD patients where it is found in the insoluble fraction. These results suggest that TRAF6 atypical ubiquitination warrants investigation in HD pathogenesis.

Adaptive response: modelling and experimental studies

Adaptive response (AR) is a term that has been generally accepted to describe the ability of a low 'priming' radiation dose to decrease the cell response to a subsequent higher 'challenging' dose. The main proposed mechanisms to explain AR are: increased efficiency of DNA repair and induction of antioxidant enzymes. A model that considers a modulation of the efficiency of DNA repair activity and of the level of antioxidant enzymes, starting from the framework of a lethal-potentially lethal (LPL) model is proposed. The LPL model has been extended with the inclusion of the dynamic variables representing the efficiency of repair, the levels of radiation induced radicals and of antioxidant enzymes. The model used here is able to describe the protective effect of a priming dose. Moreover, in agreement with the data in the literature, the simulations show that the AR happens in given priming dose and priming dose-rate ranges only, and requires at least 4 h to develop. In order to get more insights into the role of cell-cell communication as factors affecting the AR, experimental studies were planned using sparse or confluent AG1522 cell monolayer. The results obtained after gamma irradiation suggest that cell density is a crucial factor for observing an AR.

77 PREGNANCY RATES AFTER VITRIFICATION OF FRESH AND COOLED EQUINE EMBRYOS USING THE CRYOTOP METHOD

Cryopreservation of equine embryos is still not a routine procedure. Pregnancies have been obtained after transfer of vitrified embryos of less than 300 μm (Eldridge-Panuska et al. 2005). The aim of this study was to use the cryotop method (Kuwayama, 2007) to obtain pregnancies after transfer of vitrified thawed cooled and fresh embryos collected in our clinical embryo transfer programme. Embryos were assigned either to be vitrified within 3 h of collection or to be cooled for 18–24 h before vitrification. All embryos were vitrified and thawed by Cryotop Vitrification Kit® (Cryo Tech Laboratory®). Briefly, they were equilibrated in a solution containing ethylene glycol (EG), dimethylsulphoxide (DMSO) in TCM-199 for 10 to 25 min. Then they were moved to vitrification solution containing EG, DMSO, and sucrose in TCM-199 and loaded with a glass capillary onto the top of the film strip. After loading, almost all the solution was removed to leave only a thin layer covering the embryo, and the sample was quickly immersed into liquid nitrogen and covered with a protective cap. The time between entry to vitrification solution and nitrogen was from 1 to 3 min. At warming, the strip was immersed directly for 1 min into a 37°C medium containing sucrose in TCM-199. The embryo was incubated 3 min in a diluent solution, washed twice 5 min each in washing solution, and further cultured in DMEM F-12 with 10% FBS at 38.5°C 5% CO2 between 2 to 5 h. For transfer, the embryo was loaded in 0.5-mL straws. All recipient mares had ovulated 4 to 7 days before nonsurgical transfer. Pregnancies were detected 6 to 8 days later. A total of 15 embryos, grades 1 to 2, were obtained. Fresh embryos (n = 7) ranged between 250 and 800 μm, and refrigerated embryo (n = 8) diameter was between 130 and 550 μm. Pregnancy rates were 37.5% (3/8) for embryos cooled before vitrification and 28.6% (2/7) for embryos vitrified within 3 h. The overall pregnancy rate was 33.3% (5/15). Shipping cooled embryos allows maintaining a large number of recipients far away from donors, without decreasing pregnancy rate. It also makes it possible to send embryos to a specialised laboratory in order to be vitrified and preserved until recipients are available. Equine embryos collected 6 days after ovulation are generally smaller than 300 μm and have shown the highest survival rate after cryopreservation. However, the embryo recovery rate is higher when flushing is performed at Day 7 or 8. This cryopreservation protocol could provide a way to vitrify fresh and cooled embryos up to 550 μm, which would prevent the loss of valuable embryos collected in more advanced stages of development. In summary, pregnancies can be obtained after cooling for 18 to 24 h and vitrification of embryos collected 7 or 7.5 days after.

[Lumbar tuberculous spondylodiscitis: a minimally invasive surgical approach]

INTRODUCTION

Tuberculous spondylodiscitis is the most frequent and severe manifestation of extra-pulmonary tuberculosis, accounting for 40 to 50 percent of the cases with osteoarticular involvement. Although antituberculous drugs remain the cornerstone of therapy, surgical treatment still has an important role in the management of some situations. Classical approaches of radical debridement have been gradually replaced by minimally invasive surgical procedures.

CASE REPORT

The authors describe a case of an 86-year-old male, diagnosed with a L2-L3 tuberculous spondylodiscitis complicated by an anterior epidural abscess, bilateral psoas muscle abscesses and meningoencephalitis. The patient underwent surgery by minimally invasive posterior paramedian approaches with tubular retractors. A L2-L3 discectomy, drainage of the abscesses and L2-L3 percutaneous transpedicular fixation were performed. The procedure and postoperative period were uneventful and the patient had a favourable outcome.

DISCUSSION

A minimally invasive posterior approach allows adequate access to the spinal canal for neural decompression in cases of spinal infection. Combined with percutaneous internal fixation the procedure prevents the loss of vertebral alignment and facilitates an early mobilization of the patient.

Chromosomal, epigenetic and microRNA-mediated inactivation of LRP1B, a modulator of the extracellular environment of thyroid cancer cells

The low-density lipoprotein receptor-related protein (LRP1B), encoding an endocytic LDL-family receptor, is among the 10 most significantly deleted genes across 3312 human cancer specimens. However, currently the apparently crucial role of this lipoprotein receptor in carcinogenesis is not clear. Here we show that LRP1B inactivation (by chromosomal, epigenetic and microRNA (miR)-mediated mechanisms) results in changes to the tumor environment that confer cancer cells an increased growth and invasive capacity. LRP1B displays frequent DNA copy number loss and CpG island methylation, resulting in mRNA underexpression. By using CpG island reporters methylated in vitro, we found that DNA methylation disrupts a functional binding site for the histone-acetyltransferase p300 located at intron 1. We identified and validated an miR targeting LRP1B (miR-548a-5p), which is overexpressed in cancer cell lines as a result of 8q22 DNA gains. Restoration of LRP1B impaired in vitro and in vivo tumor growth, inhibited cell invasion and led to a reduction of matrix metalloproteinase 2 in the extracellular medium. We emphasized the role of an endocytic receptor acting as a tumor suppressor by modulating the extracellular environment composition in a way that constrains the invasive behavior of the cancer cells.

Lack of sexual dimorphism in femora of the eusocial and hypogonadic naked mole-rat: a novel animal model for the study of delayed puberty on the skeletal system

Sex steroid hormones are major determinants of bone morphology and quality and are responsible for sexually dimorphic skeletal traits. Hypogonadism results in suboptimal skeletal development and may lead to an increased risk of bone fracture later in life. The etiology of delayed puberty and/or hypothalamic amenorrhea is poorly understood, and experimental animal models addressing this issue are predominantly based upon short-term experimental induction of hormonal suppression via gonadotropin releasing hormone antagonists (GnRH-a). This acute change in hormone profile does not necessarily emulate the natural progression of hypogonadic bone disorders. We propose a novel animal model with which to explore the effects of chronic hypogonadism on bone quality, the naked mole-rat (NMR; Heterocephalus glaber). This mouse-size rodent may remain reproductively suppressed throughout its life, if it remains as a subordinate within the eusocial mole-rat colony. NMRs live in large colonies with a single dominant breeding female. She, primarily by using aggressive social contact, naturally suppresses the hypothalamic gonadotropic axis of subordinate NMRs and thereby their reproductive expression. However, should an NMR be separated from the dominant breeder, within less than a week reproductive hormones may become elevated and the animal attains breeding status. We questioned if sexual suppression of subordinates impact upon the development and maintenance of the femora and lead to a sexually indistinct monomorphic skeleton. Femora were obtained from male and female NMRs that were either non-breeders (subordinate) or breeders at the time of sacrifice. Diaphyseal cross-sectional morphology, metaphyseal trabecular micro-architecture and tissue mineral density of the femur were measured using microcomputed tomography and diaphyseal mechanical properties were assessed by four-point bending tests to failure. Subordinates were sexually monomorphic and showed no significant differences in body weight or femoral bone structure and quality between males and females. Femora of subordinate females differed significantly from that of breeding animals, whereas in males, the divergent trend among breeders and non-breeders did not reach statistical significance. Subordinate NMRs, naturally suppressed from entering puberty, may prove to be a useful model to tease apart the relationship between bone morphology and hypogonadism and evaluate skeletal development during pubertal maturation.

Reducing air-pollution: a new argument for getting drivers to abide by the speed limit?

Speeding is one of the main factors of car crash-risk, but it also contributes to increasing air-pollution. In two studies we attempted to lead drivers to abide by speed limits using "reducing air-pollution" as a new argument. We presented prevention messages that highlighted the role of speeding in increasing "crash-risk", "air-pollution", or both (Studies 1 and 2). The messages were also positively or negatively framed (Study 2). Given that women are more concerned with environmental issues than are men, we expected the following hypotheses to be validated for women. The message with the "air-pollution" argument was expected to be evaluated more positively than the "crash-risk" message (H1). The "air-pollution" and "crash-risk and air-pollution" messages were expected to be more effective than the "crash-risk" message on the behavioral intention to observe speed limits (H2a) and on the perceived efficacy of speed-limit observance in reducing air-pollution (H2b; Studies 1 and 2). Furthermore, positive framing was expected to be more effective than negative framing (H3), and presenting a message to be more effective than presenting no message (H4; Study 2). Broadly, our results argue in favor of our hypotheses. However in Study 2, the effects of message framing did not allow us to conclude that negative or positive framing was superior. All in all, messages with the "air-pollution" argument were more effective at leading drivers to observe speed limits. Thus, environmental protection may be a fruitful route to explore for increasing road safety.

308 GUANACO SPERM CHROMATIN EVALUATION USING TOLUIDINE BLUE

Guanacos, a wild species of South American camelids, have a high-quality fiber with great economic potential. To evaluate reproductive aptitude in guanacos, our laboratory has developed a reliable semen collection technique using electroejaculation and has applied various methods for evaluating semen characteristics. Studies for evaluating the state of sperm chromatin have also been initiated. Toluidine blue (TB) is a cationic stain that unites with the phosphate groups in the DNA, thus permitting differentiation between sperm heads according to the degree of chromatin decondensation. The objectives of this study were to determine the TB staining patterns of guanaco sperm chromatin, establish a positive control for the stain, and evaluate the effect of collagenase on sperm chromatin condensation. Semen was collected from 4 guanacos, between 6 and 9 years old, using electroejaculation. In Experiment 1, to establish a positive control for the stain, equal quantities of 1% dithiothreitol (DTT) and raw semen were incubated at room temperature for 30 s, 1.5 min, and 3 min. After incubation, smears were made and then dried, to avoid continuing the reaction, and finally were stained with 0.02% TB. A split-plot design was used with time as the splitting factor and considering the males as a block. In Experiment 2, raw semen was divided into 2 aliquots, one diluted 4 : 1 in 0.1% collagenase in HEPES-TALP-BSA medium and the other left without enzyme. Both aliquots were incubated 4 min at 37°C and, after centrifugation to remove the enzyme, smears were made and stained with TB. Spermatozoa were classified according to the degree of chromatin decondensation. Analysis of variance was performed using the males as a blocking factor and the treatment as a fixed factor. According to the degree of chromatin decondensation, three patterns of staining with TB were observed: light blue (negative, without alteration of chromatin condensation), light violet (intermediate, some degree of decondensation), and dark violet (positive, high degree of decondensation). A significant increase (P < 0.05) of sperm with highly decondensed chromatin was observed in semen incubated for 3 min with DTT when compared to 30 s of incubation. Therefore, 3 min of incubation with DTT was chosen as the positive control for Experiment 2. No significant differences in any of the 3 patterns of TB staining were observed between semen incubated with or without 0.1% collagenase. In conclusion, it is possible to use TB to evaluate the degree of chromatin decondensation in guanaco spermatozoa and to use DTT as a positive control for the stain. Treatment of guanaco semen with 0.1% collagenase did not affect sperm chromatin condensation; therefore, this enzyme can be used to decrease semen viscosity and aid handling in the laboratory.

Establishing a minimum postmortem interval of human remains in an advanced state of skeletonization using the growth rate of bryophytes and plant roots

This paper illustrates the usefulness and efficiency of botanical evidence in establishing a minimum postmortem interval (PMI). The case under analysis refers to the remains of an adult male in an advanced state of skeletonization recovered from a wooded area in northern Portugal. The skeleton showed several taphonomical changes, which included the presence of green algae, bryophytes, and growing shrub roots in, around, and through the remains. By determining the age of both the bryophytes and shrub roots, it was concluded that the minimum amount of time elapsed since death was 3 years, to which several months or a few years have to be added to account for the complete decomposition of the remains. The disappearance of the presumptive individual had occurred 6 years before and is fully consistent with the estimate of the PMI. This report illustrates a novel use of bryophytes in a forensic setting.