A morphological study of the effects of cycloleucine on the central and peripheral nervous systems of the mouse

Cycloleucine (CL) is a very potent inhibitor of S-adenosyl methionine transferase causing a rapid decline in CNS S-adenosyl methionine levels and increase in methionine in the nervous system. CL interrupts the transmethylation reaction in the CNS similar to that caused by deficiency of vitamin B12 or folic acid. CL was administered as a single dose intraperitoneally (2mg/g body weight) to mice of varying ages (21 days - 5 months). The 21 day old mice given CL 2mg/g body weight showed evidence of toxicity within 24 hours and thereafter developed progressive muscle weakness and ataxia. Animals did not survive longer than 1 week. Light and electron microscopic examination o f the central and peripheral nervous systems, from 12 hours to 7 days post-injection showed that intramyelinic vacuolation developed in the white matter of brain and cord within 12 hours but no myelin vacuolation occurred in peripheral nerves. Axonal lesions in the distal parts of motor nerves occurred within 1 2 - 2 4 hours resulting in degeneration of intramuscular nerve fibres and terminals. Motor end-plates became denervated. There was no degeneration of motor or sensory nerves in the muscle spindles. Later there was evidence of axonal degeneration in tibial and sciatic nerves. Many dorsal root ganglion cells became vacuolated or necrotic three days after administration of CL and numerous degenerated fibres were noted in the white matter of the spinal cord, especially in funiculus gracilis. The intramyelinic vacuolation in the white matter of brain and cord persisted and became more severe during the course of the experiment. In adult mice (6 weeks - 5 months) the pathology consisted mainly of distal motor axonal degeneration which developed at 1 - 2 days. Only slight intramyelinic vacuolation in white matter was noted. At 3 days later, numerous degenerated fibres were seen in the posterior columns of cervical cord, especially in the funiculus gracilis. In a second series of experiments valine (3 mg/g body weight) was given every 12 hours for 6 doses beginning either 24 or 48 hours after CL. Valine (VL) is a very effective antidote against cycloleucine and reversed its toxicity. The intramyelinic vacuolation disappeared from the white matter in the CNS leaving little residual pathology. Regenerating axons and remyelinated fibres were found in previously degenerated distal peripheral nerves and denervated motor end-plates. The reinnervation took place more rapidly in animals given VL from 24 hours after CL than 48 hours after CL. In conclusion it can be stated that CL causes a distal motor axonopathy and sensory ganglion cell necrosis in addition to the previously reported myelinic vacuolation in the CNS. The mechanism of toxicity of CL is likely to be related to the failure of transmethylation processes affecting particularly myelin basic protein and perhaps membrane turnover at active sites of transmitter release such as the neuromuscular junction

The Association between Virus Prevalence and Intercolonial Aggression Levels in the Yellow Crazy Ant, Anoplolepis Gracilipes (Jerdon).

The recent discovery of multiple viruses in ants, along with the widespread infection of their hosts across geographic ranges, provides an excellent opportunity to test whether viral prevalence in the field is associated with the complexity of social interactions in the ant population. In this study, we examined whether the association exists between the field prevalence of a virus and the intercolonial aggression of its ant host, using the yellow crazy ant (Anoplolepis gracilipes) and its natural viral pathogen (TR44839 virus) as a model system. We delimitated the colony boundary and composition of A. gracilipes in a total of 12 study sites in Japan (Okinawa), Taiwan, and Malaysia (Penang), through intercolonial aggression assay. The spatial distribution and prevalence level of the virus was then mapped for each site. The virus occurred at a high prevalence in the surveyed colonies of Okinawa and Taiwan (100% infection rate across all sites), whereas virus prevalence was variable (30%-100%) or none (0%) at the sites in Penang. Coincidentally, colonies in Okinawa and Taiwan displayed a weak intercolonial boundary, as aggression between colonies is generally low or moderate. Contrastingly, sites in Penang were found to harbor a high proportion of mutually aggressive colonies, a pattern potentially indicative of complex colony composition. Our statistical analyses further confirmed the observed correlation, implying that intercolonial interactions likely contribute as one of the effective facilitators of/barriers to virus prevalence in the field population of this ant species

Analysis of blast-induced ground vibration under surface explosion

The blasting operation is vital in the construction of tunnels and channels or in mining when encountering hard geological environments to facilitate the progress of a project. The level and range of damage due to the blast are affected by the energy of shock waves generated after explosion. The control of seismic damage is a major issue in blasting engineering and cannot be neglected. The stratum layer or buildings on the earth’s surface can be damaged when blasting-induced vibration strength exceeds the allowed range. In order to reduce the degree of damage, the patterns of blasting vibration must be studied and controlled. Therefore, the propagation characteristics of shock waves on the earth’s surface are important factors to be studied before the planning and designing of a project. This paper adopted a mutual verification method between the blasting experiment and numerical analysis results for verifying the reliability of numerical simulation based on experimental data. The numerical analysis method analyzed the dynamic mechanical behavior of blasting vibration using the finite element method. The LS-DYNA program was used to simulate TNT explosive and surface contact blasting in semi-infinite space and in propagation of the resulting seismic waves. The propagation characteristics, represented by temporal and spatial changes of surface acceleration, were investigated. The analysis results showed that post-explosion dynamic characteristics of the earth’s surface simulated by finite element method yielded promising simulation results. In addition, the propagation characteristics of stress waves were observed from the dynamic mechanical behavior of surface acceleration after explosion. That is, the maximum main stress presented a pattern of progressive attenuation with increasing distance from the blasting source. The results are able to provide reference for the protection of engineering structures from blasting vibration damages

Semiautomated optical coherence tomography-guided robotic surgery for porcine lens removal.

PurposeTo evaluate semiautomated surgical lens extraction procedures using the optical coherence tomography (OCT)-integrated Intraocular Robotic Interventional Surgical System.SettingStein Eye Institute and Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, USA.DesignExperimental study.MethodsSemiautomated lens extraction was performed on postmortem pig eyes using a robotic platform integrated with an OCT imaging system. Lens extraction was performed using a series of automated steps including robot-to-eye alignment, irrigation/aspiration (I/A) handpiece insertion, anatomic modeling, surgical path planning, and I/A handpiece navigation. Intraoperative surgical supervision and human intervention were enabled by real-time OCT image feedback to the surgeon via a graphical user interface. Manual preparation of the pig-eye models, including the corneal incision and capsulorhexis, was performed by a trained cataract surgeon before the semiautomated lens extraction procedures. A scoring system was used to assess surgical complications in a postoperative evaluation.ResultsComplete lens extraction was achieved in 25 of 30 eyes. In the remaining 5 eyes, small lens pieces (≤1.0 mm3) were detected near the lens equator, where transpupillary OCT could not image. No posterior capsule rupture or corneal leakage occurred. The mean surgical duration was 277 seconds ± 42 (SD). Based on a 3-point scale (0 = no damage), damage to the iris was 0.33 ± 0.20, damage to the cornea was 1.47 ± 0.20 (due to tissue dehydration), and stress at the incision was 0.97 ± 0.11.ConclusionsNo posterior capsule rupture was reported. Complete lens removal was achieved in 25 trials without significant surgical complications. Refinements to the procedures are required before fully automated lens extraction can be realized

Non-destructive quantitation of spermine in human prostate tissue samples using HRMAS 1H NMR spectroscopy at 9.4 T

AbstractWe present the results of a study of human prostate specimens evaluated by high resolution magic angle spinning 1H nuclear magnetic resonance (NMR) spectroscopy at 400 MHz (9.4 T) and by quantitative histopathology. We demonstrate that NMR and pathology data can be obtained from the same intact specimens, and report for the first time a linear correlation between the NMR measured concentration of spermine, a proposed endogenous inhibitor to prostate cancer growth, and the volume percentage of normal prostatic epithelial cells as quantified by histopathology. Our results show that NMR may serve as a critical tool for the investigation of the inhibitory mechanism of spermine in human subjects

EVALUATION OF ELBOW AND FOREARM MOTION BETWEEN SIDEARM AND OVERHAND PITCHING

This study is to analyze the differences in kinematics, electromyography (EMG) and ultrasonography between two types of pitchers. We intend to observe and simulate the muscles around glenohumeral and elbow joints in different pitching motions and hope to discover the connections and differences in between. 12 pitchers from the top level were recruited. Larger elbow flexion was found in sidearm pitchers during the acceleration phase. Decrease of the distance of nerve to medial epicondyle was also found as the elbow moved to a more flexed position. More anterior translation of the ulnar nerve might occur during acceleration phase. Slightly lower flexor carpi radialis (FCR) activity was displayed in sidearm pitchers, showing that FCR might play a less crucial role in protecting medial elbow by providing less varus torque

The complete mitochondrial genome of a parthenogenetic ant Monomorium triviale (Hymenoptera: Formicidae)

Monomorium is one of the most species-rich yet taxonomically problematic ant genus. An East Asian species, M. triviale Wheeler, W.M., 1906, is reproduced by obligate thelytokous parthenogenesis and performs strict reproductive division of labor. We sequenced the M. triviale mitogenome using next-generation sequencing methods. The circular mitogenome of M. triviale was 16, 290 bp in length, consisting of 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNAs, and a single non-coding region of 568 bp. The base composition was AT-biased (82%). Gene order rearrangements were detected and likely to be unique to the genus Monomorium. We announce the M. triviale mitogenome as additional genomic resources for elucidating phylogenetic and taxonomic problems of Monomorium and comparative genomics of parthenogenetic ant species

Factors affecting office rent in Kuala Lumpur (KL)

The oversupply of office space in the Golden Triangle Kuala Lumpur (GTKL) and slow on-going demand has resulted in pressure on rental performance. Studies have shown that there are several strategies to improve rent performance. The purpose of this paper is to obtain a deeper understanding of these strategies and their applicability in the context of GTKL. Questionnaires were distributed to 42 office buildings in the GTKL. A total of 212 tenants completed the questionnaire and secondary data on building certifications and the building average rents were extracted from reliable property website sources. The results suggest that office building rental performance can be improved if the building management charges lower rent to longer-stay tenants, attracts more foreign-owned or bigger-sized firm and gets Multimedia Super Corridor (MSC) or Green certifications. The implications for managers and theories in this regard are then discussed