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Sample records for adjacent level degeneration

  1. Adjacent segment degeneration after single-level anterior cervical decompression and fusion: disc space distraction and its impact on clinical outcomes.

    PubMed

    Li, Jia; Li, Yongqian; Kong, Fanlong; Zhang, Di; Zhang, Yingze; Shen, Yong

    2015-03-01

    The purpose of this study was to find whether excessive distraction of the disc space for cage insertion was a risk factor for adjacent segment degeneration (ASD) after anterior cervical decompression and fusion (ACDF). One hundred and sixteen consecutive patients who underwent ACDF for single-level cervical disc herniation between June 2006 and November 2008 were retrospectively reviewed. Preoperative, postoperative and final follow-up disc height (DH), sagittal segmental alignment (SSA), and sagittal alignment of the cervical spine (SACS) were measured and compared between the ASD group and non-ASD group. In 116 patients, ASD was radiographically proven in 28 (24.1%) patients. The clinical outcomes were significantly improved compared to the preoperative scores in both groups. However, the postoperative and final follow-up DH of the ASD group were significantly higher than in the non-ASD group (p<0.05). In addition, the postoperative DH was significantly correlated with the postoperative or final follow-up SSA (p<0.05). However, postoperative DH was not found to significantly correlate with postoperative or final follow-up SACS (p=0.072 and p=0.096, respectively). Multivariate analysis showed that postoperative DH was the most significant risk factor for ASD. The clinical outcomes of ACDF for single-level degenerative cervical disc disease were satisfactory. Postoperative DH (the distracted distance) had the greatest impact on the incidence of ASD. Excessive disc space distraction is a considerable risk factor for the development of radiographic ASD.

  2. Repeated adjacent-segment degeneration after posterior lumbar interbody fusion.

    PubMed

    Okuda, Shinya; Oda, Takenori; Yamasaki, Ryoji; Maeno, Takafumi; Iwasaki, Motoki

    2014-05-01

    One of the most important sequelae affecting long-term results is adjacent-segment degeneration (ASD) after posterior lumbar interbody fusion (PLIF). Although several reports have described the incidence rate, there have been no reports of repeated ASD. The purpose of this report was to describe 1 case of repeated ASD after PLIF. A 62-year-old woman with L-4 degenerative spondylolisthesis underwent PLIF at L4-5. At the second operation, L3-4 PLIF was performed for L-3 degenerative spondylolisthesis 6 years after the primary operation. At the third operation, L2-3 PLIF was performed for L-2 degenerative spondylolisthesis 1.5 years after the primary operation. Vertebral collapse of L-1 was detected 1 year after the third operation, and the collapse had progressed. At the fourth operation, 3 years after the third operation, vertebral column resection of L-1 and replacement of titanium mesh cages with pedicle screw fixation between T-4 and L-5 was performed. Although the patient's symptoms resolved after each operation, the time between surgeries shortened. The sacral slope decreased gradually although each PLIF achieved local lordosis at the fused segment.

  3. Prevalence of adjacent segment disc degeneration in patients undergoing anterior cervical discectomy and fusion based on pre-operative MRI findings.

    PubMed

    Lundine, Kristopher M; Davis, Gavin; Rogers, Myron; Staples, Margaret; Quan, Gerald

    2014-01-01

    Anterior cervical discectomy and fusion (ACDF) is a widely accepted surgical treatment for symptomatic cervical spondylosis. Some patients develop symptomatic adjacent segment degeneration, occasionally requiring further treatment. The cause and prevalence of adjacent segment degeneration and disease is unclear at present. Proponents for motion preserving surgery such as disc arthroplasty argue that this technique may decrease the "strain" on adjacent discs and thus decrease the incidence of symptomatic adjacent segment degeneration. The purpose of this study was to assess the pre-operative prevalence of adjacent segment degeneration in patients undergoing ACDF. A database review of three surgeons' practice was carried out to identify patients who had undergone a one- or two-level ACDF for degenerative disc disease. Patients were excluded if they were operated on for recent trauma, had an inflammatory arthropathy (for example, rheumatoid arthritis), or had previous spine surgery. The pre-operative MRI of each patient was reviewed and graded using a standardised methodology. One hundred and six patient MRI studies were reviewed. All patients showed some evidence of intervertebral disc degeneration adjacent to the planned operative segment(s). Increased severity of disc degeneration was associated with increased age and operative level, but was not associated with sagittal alignment. Disc degeneration was more common at levels adjacent to the surgical level than at non-adjacent segments, and was more severe at the superior adjacent level compared with the inferior adjacent level. These findings support the theory that adjacent segment degeneration following ACDF is due in part to the natural history of cervical spondylosis.

  4. Magnetic resonance imaging on disc degeneration changes after implantation of an interspinous spacer and fusion of the adjacent segment

    PubMed Central

    Liu, Xiaokang; Liu, Yingjie; Lian, Xiaofeng; Xu, Jianguang

    2015-01-01

    The aim of the study was to investigate the changes of the lumbar intervertebral disc degeneration by magnetic resonance imaging (MRI) after the implantation of interspinous device and the fusion of the adjacent segment. A total of 62 consecutive patients suffering L5/S1 lumbar disc herniation (LDH) with concomitant disc space narrowing or low-grade instability up to 5 mm translational slip in L5/S1 level were treated with lumbar interbody fusion (LIF) via posterior approach. Thirty-four of these patients (Coflex group) received an additional implantation of the interspinous spacer device (Coflex™) in the level L4/L5, while the rest of 28 patients (fusion group) underwent the fusion surgery alone. Clinical and radiographic examinations were performed at pre- and postoperative visits to compare the clinical outcomes and the changes of the L4/L5 vertebral disc degeneration on MRI in both Coflex and fusion group. Although both Coflex and fusion group showed improvements of the clinical outcomes assessed by the Oswestry Disability Index (ODI) after surgery, patients in Coflex group had more significant amelioration (P < 0.05) compared to fusion group. During follow up, the postoperative disc degeneration changes in Coflex group assessed by the relative signal intensity (RSI) differed from those in fusion group (P < 0.05). The supplemental implantation of Coflex™ after the fusion surgery could delay the disc degeneration of the adjacent segment. PMID:26131210

  5. Magnetic resonance imaging on disc degeneration changes after implantation of an interspinous spacer and fusion of the adjacent segment.

    PubMed

    Liu, Xiaokang; Liu, Yingjie; Lian, Xiaofeng; Xu, Jianguang

    2015-01-01

    The aim of the study was to investigate the changes of the lumbar intervertebral disc degeneration by magnetic resonance imaging (MRI) after the implantation of interspinous device and the fusion of the adjacent segment. A total of 62 consecutive patients suffering L5/S1 lumbar disc herniation (LDH) with concomitant disc space narrowing or low-grade instability up to 5 mm translational slip in L5/S1 level were treated with lumbar interbody fusion (LIF) via posterior approach. Thirty-four of these patients (Coflex group) received an additional implantation of the interspinous spacer device (Coflex™) in the level L4/L5, while the rest of 28 patients (fusion group) underwent the fusion surgery alone. Clinical and radiographic examinations were performed at pre- and postoperative visits to compare the clinical outcomes and the changes of the L4/L5 vertebral disc degeneration on MRI in both Coflex and fusion group. Although both Coflex and fusion group showed improvements of the clinical outcomes assessed by the Oswestry Disability Index (ODI) after surgery, patients in Coflex group had more significant amelioration (P < 0.05) compared to fusion group. During follow up, the postoperative disc degeneration changes in Coflex group assessed by the relative signal intensity (RSI) differed from those in fusion group (P < 0.05). The supplemental implantation of Coflex™ after the fusion surgery could delay the disc degeneration of the adjacent segment.

  6. Reduction in adjacent-segment degeneration after multilevel posterior lumbar interbody fusion with proximal DIAM implantation.

    PubMed

    Lu, Kang; Liliang, Po-Chou; Wang, Hao-Kuang; Liang, Cheng-Loong; Chen, Jui-Sheng; Chen, Tai-Been; Wang, Kuo-Wei; Chen, Han-Jung

    2015-08-01

    OBJECT Multilevel long-segment lumbar fusion poses a high risk for future development of adjacent-segment degeneration (ASD). Creating a dynamic transition zone with an interspinous process device (IPD) proximal to the fusion has recently been applied as a method to reduce the occurrence of ASD. The authors report their experience with the Device for Intervertebral Assisted Motion (DIAM) implanted proximal to multilevel posterior lumbar interbody fusion (PLIF) in reducing the development of proximal ASD. METHODS This retrospective study reviewed 91 cases involving patients who underwent 2-level (L4-S1), 3-level (L3-S1), or 4-level (L2-S1) PLIF. In Group A (42 cases), the patients received PLIF only, while in Group B (49 cases), an interspinous process device, a DIAM implant, was put at the adjacent level proximal to the PLIF construct. Bone resection at the uppermost segment of the PLIF was equally limited in the 2 groups, with preservation of the upper portion of the spinous process/lamina and the attached supraspinous ligament. Outcome measures included a visual analog scale (VAS) for low-back pain and leg pain and the Oswestry Disability Index (ODI) for functional impairment. Anteroposterior and lateral flexion/extension radiographs were used to evaluate the fusion status, presence and patterns of ASD, and mobility of the DIAM-implanted segment. RESULTS Solid interbody fusion without implant failure was observed in all cases. Radiographic ASD occurred in 20 (48%) of Group A cases and 3 (6%) of Group B cases (p < 0.001). Among the patients in whom ASD was identified, 9 in Group A and 3 in Group B were symptomatic; of these patients, 3 in Group A and 1 in Group B underwent a second surgery for severe symptomatic ASD. At 24 months after surgery, Group A patients fared worse than Group B, showing higher mean VAS and ODI scores due to symptoms related to ASD. At the final follow-up evaluations, as reoperations had been performed to treat symptomatic ASD in some

  7. Analysis of adjacent segment degeneration with laminectomy above a fused lumbar segment.

    PubMed

    Gard, Andrew P; Klopper, Hendrik B; Doran, Stephen E; Hellbusch, Leslie C

    2013-11-01

    Although recent data suggests that lumbar fusion with decompression contributes to some marginal acceleration of adjacent segment degeneration (ASD), few studies have evaluated whether it is safe to perform a laminectomy above a fused segment. This study investigates the hypothesis that laminectomy above a fused lumbar segment does not increase the incidence of ASD, and assesses the benefits and risks of performing a laminectomy above a lumbar fusion. A retrospective review of 171 patients who underwent decompression and instrumented fusion of the lumbar spine was performed to analyze the association between ASD and laminectomy above the fused lumbar segment. Patients were divided into two groups - one group with instrumented fusion alone and the other group with instrumented fusion plus laminectomy above the fused segment. Of the 171 patients, 34 underwent additional decompressive laminectomy above the fused segment. There was a significant increase in ASD incidence as well as progression of ASD grade in both groups. There was no significant increase in ASD in patients with decompressive laminectomy above the fused lumbar segment compared to patients with laminectomy limited to the fused segment. This retrospective review of 171 patients who underwent decompression and instrumented fusion with follow-up radiographs demonstrates that laminectomy decompression above a fused segment does not significantly increase radiographic ASD. There is, however, a significant increase in ASD over time, which was observed throughout the entire cohort likely representing a natural progression of lumbar spondylosis above the fusion segment.

  8. Older literature review of increased risk of adjacent segment degeneration with instrumented lumbar fusions

    PubMed Central

    Epstein, Nancy E.

    2016-01-01

    Background: Adjacent segment degeneration (ASD) following lumbar spine surgery occurs in up to 30% of cases, and descriptions of such changes are not new. Here, we review some of the older literature concerning the rate of ASD, typically more severe cephalad than caudad, and highly correlated with instrumented fusions. Therefore, for degenerative lumbar disease without frank instability, ASD would be markedly reduced by avoiding instrumented fusions. Methods: In a prior review, the newer literature regarding the frequency of ASD following lumbar instrumented fusions (e.g., transforaminal or posterior lumbar interbody fusions [TLIF/PLIF] fusions or occasionally, posterolateral fusions [PLFs]) was presented. Some studies cited an up to an 18.5% incidence of ASD following instrumented versus noninstrumented fusions/decompressions alone (5.6%). A review of the older literature similarly documents a higher rate of ASD following instrumented fusions performed for degenerative lumbar disease alone. Results: More frequent and more severe ASD follows instrumented lumbar fusions performed for degenerative lumbar disease without instability. Alternatively, this entity should be treated with decompressions alone or with noninstrumented fusions, without the addition of instrumentation. Conclusions: Too many studies assume that TLIF, PLIF, and even PLF instrumented fusions are the “gold standard of care” for dealing with degenerative disease of the lumbar spine without documented instability. It is time to correct that assumption, and reassess the older literature along with the new to confirm that decompression alone and noninstrumented fusion avoid significant morbidity and even potentially mortality attributed to unnecessary instrumentation. PMID:26904370

  9. Stress Reduction in Adjacent Level Discs via Dynamic Instrumentation: A Finite Element Analysis

    PubMed Central

    Castellvi, Antonio E.; Huang, Hao; Vestgaarden, Tov; Saigal, Sunil; Pienkowski, David

    2007-01-01

    Background Conventional (rigid) fusion instrumentation is believed to accelerate the degeneration of adjacent discs by increasing stresses caused by motion discontinuity. Fusion instrumentation that employs reduced rod stiffness and increased axial motion, or dynamic instrumentation, may partially alleviate this problem, but the effects of this instrumentation on the stresses in the adjacent disc are unknown. We used a finiteelement model to calculate and compare the stresses in the adjacent-level disc that are induced by rigid and dynamic posterior lumbar fusion instrumentation. Methods A 3-dimensional finite-element model of the lumbar spine was obtained that simulated flexion and extension. The L5–S1 segment of this model was fused, and the L4–L5 segment was fixed with rigid or dynamic instrumentation. The mechanical properties of the dynamic instrumentation were determined by laboratory testing and then used in the finite-element model. Peak stresses in the lumbar discs were calculated and compared. Results The reduced-stiffness component of the dynamic instrumentation was associated with a 1% to 2% reduction in peak compressive stresses in the adjacent-level disc (at 45° flexion), and the increased axial motion component of this instrumentation reduced peak disc stress by 8% to 9%. Areas of disc tissue exposed to 80% of peak stresses of 6.17 MPa were 47% less for discs adjacent to dynamic instrumentation than for those adjacent to rigid instrumentation. Conclusions Reduced stiffness and increased axial motion of dynamic posterior lumbar fusion instrumentation designs result in an approximately 10% cumulative stress reduction for each flexion cycle. The effect of this stress reduction over many cycles may be substantial. Clinical Relevance The cumulative effect of this reduced amplitude and distribution of peak stresses in the adjacent disc may partially alleviate the problem of adjacent-level disc degeneration. PMID:25802582

  10. Comparison of percutaneous endoscopic lumbar discectomy and open lumbar surgery for adjacent segment degeneration and recurrent disc herniation.

    PubMed

    Chen, Huan-Chieh; Lee, Chih-Hsun; Wei, Li; Lui, Tai-Ngar; Lin, Tien-Jen

    2015-01-01

    Objective. The goal of the present study was to examine the clinical results of percutaneous endoscopic lumbar discectomy (PELD) and open lumbar surgery for patients with adjacent segment degeneration (ASD) and recurrence of disc herniation. Methods. From December 2011 to November 2013, we collected forty-three patients who underwent repeated lumbar surgery. These patients, either received PELD (18 patients) or repeated open lumbar surgery (25 patients), due to ASD or recurrence of disc herniation at L3-4, L4-5, or L5-S1 level, were assigned to different groups according to the surgical approaches. Clinical data were assessed and compared. Results. Mean blood loss was significantly less in the PELD group as compared to the open lumbar surgery group (P < 0.0001). Hospital stay and mean operating time were shorter significantly in the PELD group as compared to the open lumbar surgery group (P < 0.0001). Immediate postoperative pain improvement in VAS was 3.5 in the PELD group and -0.56 in the open lumbar surgery group (P < 0.0001). Conclusion. For ASD and recurrent lumbar disc herniation, PELD had more advantages over open lumbar surgery in terms of reduced blood loss, shorter hospital stay, operating time, fewer complications, and less postoperative discomfort.

  11. A prospective randomised study on the long-term effect of lumbar fusion on adjacent disc degeneration.

    PubMed

    Ekman, Per; Möller, Hans; Shalabi, Adel; Yu, Yiang Xiao; Hedlund, Rune

    2009-08-01

    The existence and importance of an accelerated adjacent segment disc degeneration (ASD) after lumbar fusion have previously not been demonstrated by RCTs. The objectives of this study were, to determine whether lumbar fusion in the long term accelerates degenerative changes in the adjacent disc and whether this affects the outcome, by using a prospective randomised design. A total of 111 patients, aged 18-55, with isthmic spondylolisthesis were randomised to exercise (EX, n = 34) or posterolateral fusion (PLF, n = 77), with (n = 37) or without pedicle screw instrumentation (n = 40). The minimum 10 years FU rate was 72%, with a mean FU time of 12.6 years (range 10-17 years). Three radiographic methods of ASD quantification were used, i.e. two digital radiographic measurement methods and the semi quantitative UCLA grading scale. One digital measurement method showed a mean disc height reduction by 2% in the EX group and by 15% in the PLF group (p = 0.0016), and the other showed 0.5 mm more disc height reduction in the PLF compared to the Ex group (ns). The UCLA grading scale showed normal discs in 100% of patients in the EX group, compared to 62% in the PLF group (p = 0.026). There were no significant differences between instrumented and non-instrumented patients. In patients with laminectomy we found a significantly higher incidence of ASD compared to non laminectomised patients (22/47 vs. 2/16 respectively, p = 0.015). In the longitudinal analysis, the posterior and anterior disc heights were significantly reduced in the PLF group, whereas in the EX group only the posterior disc height was significantly reduced. Except for global outcome, which was significantly better for patients without ASD, the clinical outcome was not statistically different in patients with and without ASD. In conclusion, the long-term RCT shows that fusion accelerates degenerative changes at the adjacent level compared with natural history. The study suggests that not only fusion, but also

  12. Radiologic Findings and Risk Factors of Adjacent Segment Degeneration after Anterior Cervical Discectomy and Fusion : A Retrospective Matched Cohort Study with 3-Year Follow-Up Using MRI

    PubMed Central

    So, Wan-Soo; Ku, Min-Geun; Kim, Sang-Hyeon; Kim, Dong-Won; Lee, Byung-Hun

    2016-01-01

    Objective The purpose of this study was to figure out the radiologic findings and risk factors related to adjacent segment degeneration (ASD) after anterior cervical discectomy and fusion (ACDF) using 3-year follow-up radiography, computed tomography (CT), and magnetic resonance image (MRI). Methods A retrospective matched comparative study was performed for 64 patients who underwent single-level ACDF with a cage and plate. Radiologic parameters, including upper segment range of motion (USROM), lower segment range of motion (LSROM), upper segment disc height (UDH), and lower segment disc height (LDH), clinical outcomes assessed with neck and arm visual analogue scale (VAS), and risk factors were analyzed. Results Patients were categorized into the ASD (32 patients) and non-ASD (32 patients) group. The decrease of UDH was significantly greater in the ASD group at each follow-up visit. At 36 months postoperatively, the difference for USROM value from the preoperative one significantly increased in the ASD group than non-ASD group. Preoperative other segment degeneration was significantly associated with the increased incidence of ASD at 36 months. However, pain intensity for the neck and arm was not significantly different between groups at any post-operative follow-up visit. Conclusion The main factor affecting ASD is preoperative other segment degeneration out of the adjacent segment. In addition, patients over the age of 50 are at higher risk of developing ASD. Although there was definite radiologic degeneration in the ASD group, no significant difference was observed between the ASD and non-ASD groups in terms of the incidence of symptomatic disease. PMID:26962418

  13. The Efficacy of Lumbar Hybrid Stabilization Using the DIAM™ to Delay Adjacent Segment Degeneration: An Intervention Comparison Study With a Minimum Two-Year Follow-up.

    PubMed

    Lee, Chang-Hyun; Hyun, Seung-Jae; Kim, Ki-Jeong; Jahng, Tae-Ahn; Yoon, Sang Hoon; Kim, Hyun-Jib

    2013-04-29

    BACKGROUND:: Although posterior lumbar interbody fusion (PLIF) has a successful fusion rate, the long-term outcome of PLIF is occasionally below expectations because of adjacent segment degeneration (ASD). OBJECTIVE:: To evaluate the ability of hybrid stabilization using DIAM(Device for Interspinous Assisted Motion) to delay ASD. METHODS:: An intervention comparison study of 75 patients (hybrid, 25; PLIF, 50) was performed. The indications for hybrid stabilization were facet joint degeneration, Pfirrmann grade II-III, and stenosis at the rostral adjacent segment. The PLIF group consisted of patients matched for age, gender, and fusion. The hybrid stabilization procedure included traditional PLIF and DIAM installation at a superior adjacent segment. The outcomes were analyzed using linear mixed model analysis. Conditional logistic regression was performed to calculate the odds ratio for the association of surgical methods. RESULTS:: The hybrid group (24%) revealed fewer ASDs than the PLIF group (48%). Among ASDs, spondylolisthesis occurred more frequently in the PLIF group than the hybrid group. Hybrid surgery was significantly associated with ASD; the odds ratio for hybrid surgery was 0.28 when compared to PLIF. Foraminal height of the PLIF group decreased more than the hybrid group (P=.01). Segmental mobility showed a greater increase in the PLIF group than the hybrid group (P=.04). However, the clinical outcomes did not show significant differences between the groups. CONCLUSION:: Hybrid stabilization using DIAM and pedicle screws can be used for patients with facet degeneration at adjacent segments but should be further investigated.

  14. Enhancement of Lumbar Fusion and Alleviation of Adjacent Segment Disc Degeneration by Intermittent PTH(1-34) in Ovariectomized Rats.

    PubMed

    Zhou, Zhuang; Tian, Fa-Ming; Gou, Yu; Wang, Peng; Zhang, Heng; Song, Hui-Ping; Shen, Yong; Zhang, Ying-Ze; Zhang, Liu

    2016-04-01

    Osteoporosis, which is prevalent in postmenopausal or aged populations, is thought to be a contributing factor to adjacent segment disc degeneration (ASDD), and the incidence and extent of ASDD may be augmented by osteopenia. Parathyroid hormone (PTH) (1-34) has already been shown to be beneficial in osteoporosis, lumbar fusion and matrix homeostasis of intervertebral discs. However, whether PTH(1-34) has a reversing or retarding effect on ASDD in osteopenia has not been confirmed. In the present study, we evaluated the effects of intermittent PTH(1-34) on ASDD in an ovariectomized (OVX) rat model. One hundred 3-month-old female Sprague-Dawley rats underwent L4 -L5 posterolateral lumbar fusion (PLF) with spinous-process wire fixation 4 weeks after OVX surgery. Control groups were established accordingly. PTH(1-34) was intermittently administered immediately after PLF surgery and lasted for 8 weeks using the following groups (n = 20) (V = vehicle): Sham+V, OVX+V, Sham+PLF+V, OVX+PLF+V, OVX+PLF+PTH. The fused segments showed clear evidence of eliminated motion on the fusion-segment based on manual palpation. Greater new bone formation in histology was observed in PTH-treated animals compared to the control group. The extent of ASDD was significantly increased by ovariotomy. Intermittent PTH(1-34) significantly alleviated ASDD by preserving disc height, microvessel density, relative area of vascular buds, endplate thickness and the relative area of endplate calcification. Moreover, protein expression results showed that PTH(1-34) not only inhibited matrix degradation by decreasing MMP-13, ADAMTS-4 and Col-I, but also promote matrix synthesis by increasing Col-II and Aggrecan. In conclusion, PTH(1-34), which effectively improves lumbar fusion and alleviates ASDD in ovariectomized rats, may be a potential candidate to ameliorate the prognosis of lumbar fusion in osteopenia.

  15. Adjacent level spondylodiscitis after anterior cervical decompression and fusion.

    PubMed

    Basu, Saumyajit; Sreeramalingam, Rathinavelu

    2012-05-01

    Postoperative spondylodiscitis after anterior cervical decompression and fusion (ACDF) is rare, but the same occurring at adjacent levels without disturbing the operated level is very rare. We report a case, with 5 year followup, who underwent ACDF from C5 to C7 for cervical spondylotic myelopathy. He showed neurological improvement after surgery but developed discharging sinus after 2 weeks, which healed with antibiotics. He improved on his preoperative symptoms well for the first 2 months. He started developing progressive neck pain and myelopathy after 3 months and investigations revealed spondylodiscitis at C3 and C4 with erosion, collapse, and kyphosis, without any evidence of implant failure or graft rejection at the operated level. He underwent reexploration and implant removal at the operated level (there was good fusion from C5 to C7) followed by debridement/decompression at C3, C4 along with iliac crest bone grafting and stabilization with plate and screws after maximum correction of kyphosis. The biopsy specimen grew Pseudomonas aeruginosa and appropriate sensitive antibiotics (gentamycin and ciprofloxacin) were given for 6 weeks. He was under regular followup for 5 years his myelopathy resolved completely and he is back to work. Complete decompression of the cord and fusion from C2 to C7 was demonstrable on postoperative imaging studies without any evidence of implant loosening or C1/C2 instability at the last followup. PMID:22719127

  16. Adjacent level disease following lumbar spine surgery: A review

    PubMed Central

    Epstein, Nancy E.

    2015-01-01

    Background: Instrumented lumbar spine surgery is associated with an increased risk of adjacent segment disease (ASD). Multiple studies have explored the various risk factors contributing to ASD that include; fusion length (especially, three or more levels), sagittal malalignment, facet injury, advanced age, and prior cephalad degenerative disease. Methods: In this selective review of ASD, following predominantly instrumented fusions for lumbar degenerative disease, patients typically underwent open versus minimally invasive surgery (MIS), transforaminal lumbar interbody fusions (TLIFs), posterior lumbar interbody fusions (PLIFs), or rarely posterolateral lumbar instrumented or noninstrumented fusions (posterolateral lumbar fusion). Results: The incidence of ASD, following open or MI lumbar instrumented fusions, ranged up to 30%; notably, the addition of instrumentation in different series did not correlate with improved outcomes. Alternatively, in one series, at 164 postoperative months, noninstrumented lumbar fusions reduced the incidence of ASD to 5.6% versus 18.5% for ASD performed with instrumentation. Of interest, dynamic instrumented/stabilization techniques did not protect patients from ASD. Furthermore, in a series of 513 MIS TLIF, there was a 15.6% incidence of perioperative complications that included; a 5.1% frequency of durotomy and a 2.3% instrumentation failure rate. Conclusions: The incidence of postoperative ASD (up to 30%) is greater following either open or MIS instrumented lumbar fusions (e.g., TLIF/PLIF), while decompressions with noninstrumented fusions led to a much smaller 5.6% risk of ASD. Other findings included: MIS instrumented fusions contributed to higher perioperative complication rates, and dynamic stabilization did not protect against ASD. PMID:26693387

  17. Particulate Matter Levels in Ambient Air Adjacent to Industrial Area

    NASA Astrophysics Data System (ADS)

    Mohamed, R. M. S. R.; Nizam, N. M. S.; Al-Gheethi, A. A.; Lajis, A.; Kassim, A. H. M.

    2016-07-01

    Air quality in the residential areas adjacent to the industrial regions is of great concern due to the association with human health risks. In this work, the concentrations of particulate matter (PM10) in the ambient air of UTHM campus was investigated tostudy the air qualityand their compliance to the Malaysian Ambient Air Quality Guidelines (AAQG). The PM10 samples were taken over 24 hours from the most significant area at UTHM including Stadium, KolejKediamanTunDr. Ismail (KKTDI) and MakmalBahan. The meteorological parameters; temperature, relative humidity, wind speed and wind direction as well as particulate matterwere estimated by using E-Sampler Particulate Matter (PM10) Collector. The highest concentrations of PM10 (55.56 µg/m3) was recorded at MakmalBahan during the working and weekend days. However, these concentrations are less than 150 pg/m3. It can be concluded that although UTHM is surrounded by the industrial area, the air quality in the campus still within the standards limits.

  18. Decreased Transcription Factor Binding Levels Nearby Primate Pseudogenes Suggest Regulatory Degeneration

    PubMed Central

    Douglas, Gavin M.; Wilson, Michael D.; Moses, Alan M.

    2016-01-01

    Characteristics of pseudogene degeneration at the coding level are well-known, such as a shift toward neutral rates of nonsynonymous substitutions and gain of frameshift mutations. In contrast, degeneration of pseudogene transcriptional regulation is not well understood. Here, we test two predictions of regulatory degeneration along a pseudogenized lineage: 1) Decreased transcription factor (TF) binding and 2) accelerated evolution in putative cis-regulatory regions. We find evidence for decreased TF binding levels nearby two primate pseudogenes compared with functional liver genes. However, the majority of TF-bound sequences nearby pseudogenes do not show evidence for lineage-specific accelerated rates of evolution. We conclude that decreases in TF binding level could be a marker for regulatory degeneration, while sequence degeneration in primate cis-regulatory modules may be obscured by background rates of TF binding site turnover. PMID:26882985

  19. Assessment of heavy metal levels in surface sediments of estuaries and adjacent coastal areas in China

    NASA Astrophysics Data System (ADS)

    Liu, Xianbin; Li, Deliang; Song, Guisheng

    2016-05-01

    This article investigates the variations of contamination levels of heavy metals such as copper, lead, chromium, cadmium, zinc, arsenic, and mercury over time in surface sediments of the Changjiang River Estuary (CRE), Yellow River Estuary (YRE), Pearl River Estuary (PRE), and their adjacent coastal areas in China. The contamination factor (CF), pollution load index (PLI), and geoaccumulation index (I geo) are used to evaluate the quality of the surface sediments in the study areas. The results showed that the CRE, YRE, and their adjacent coastal areas were at a low risk of contamination in terms of heavy metals, while the PRE and its adjacent coastal area were at a moderate level. By comparison, the concentrations of heavy metals in the surface sediments of the YRE and its adjacent coastal area were relatively lower than those in the CRE, PRE, and their adjacent coastal areas.

  20. Biomechanics of Disc Degeneration

    PubMed Central

    Palepu, V.; Kodigudla, M.; Goel, V. K.

    2012-01-01

    Disc degeneration and associated disorders are among the most debated topics in the orthopedic literature over the past few decades. These may be attributed to interrelated mechanical, biochemical, and environmental factors. The treatment options vary from conservative approaches to surgery, depending on the severity of degeneration and response to conservative therapies. Spinal fusion is considered to be the “gold standard” in surgical methods till date. However, the association of adjacent level degeneration has led to the evolution of motion preservation technologies like spinal arthroplasty and posterior dynamic stabilization systems. These new technologies are aimed to address pain and preserve motion while maintaining a proper load sharing among various spinal elements. This paper provides an elaborative biomechanical review of the technologies aimed to address the disc degeneration and reiterates the point that biomechanical efficacy followed by long-term clinical success will allow these nonfusion technologies as alternatives to fusion, at least in certain patient population. PMID:22745914

  1. Biomechanics of Artificial Disc Replacements Adjacent to a 2-Level Fusion in 4-Level Hybrid Constructs: An In Vitro Investigation

    PubMed Central

    Liao, Zhenhua; Fogel, Guy R.; Wei, Na; Gu, Hongsheng; Liu, Weiqiang

    2015-01-01

    Background The ideal procedure for multilevel cervical degenerative disc diseases remains controversial. Recent studies on hybrid surgery combining anterior cervical discectomy and fusion (ACDF) and artificial cervical disc replacement (ACDR) for 2-level and 3-level constructs have been reported in the literature. The purpose of this study was to estimate the biomechanics of 3 kinds of 4-level hybrid constructs, which are more likely to be used clinically compared to 4-level arthrodesis. Material/Methods Eighteen human cadaveric spines (C2–T1) were evaluated in different testing conditions: intact, with 3 kinds of 4-level hybrid constructs (hybrid C3–4 ACDR+C4–6 ACDF+C6–7ACDR; hybrid C3–5ACDF+C5–6ACDR+C6–7ACDR; hybrid C3–4ACDR+C4–5ACDR+C5–7ACDF); and 4-level fusion. Results Four-level fusion resulted in significant decrease in the C3–C7 ROM compared with the intact spine. The 3 different 4-level hybrid treatment groups caused only slight change at the instrumented levels compared to intact except for flexion. At the adjacent levels, 4-level fusion resulted in significant increase of contribution of both upper and lower adjacent levels. However, for the 3 hybrid constructs, significant changes of motion increase far lower than 4P at adjacent levels were only noted in partial loading conditions. No destabilizing effect or hypermobility were observed in any 4-level hybrid construct. Conclusions Four-level fusion significantly eliminated motion within the construct and increased motion at the adjacent segments. For all 3 different 4-level hybrid constructs, ACDR normalized motion of the index segment and adjacent segments with no significant hypermobility. Compared with the 4-level ACDF condition, the artificial discs in 4-level hybrid constructs had biomechanical advantages compared to fusion in normalizing adjacent level motion. PMID:26694835

  2. MRI quantification of human spine cartilage endplate geometry: Comparison with age, degeneration, level, and disc geometry.

    PubMed

    DeLucca, John F; Peloquin, John M; Smith, Lachlan J; Wright, Alexander C; Vresilovic, Edward J; Elliott, Dawn M

    2016-08-01

    Geometry is an important indicator of disc mechanical function and degeneration. While the geometry and associated degenerative changes in the nucleus pulposus and the annulus fibrosus are well-defined, the geometry of the cartilage endplate (CEP) and its relationship to disc degeneration are unknown. The objectives of this study were to quantify CEP geometry in three dimensions using an MRI FLASH imaging sequence and evaluate relationships between CEP geometry and age, degeneration, spinal level, and overall disc geometry. To do so, we assessed the MRI-based measurements for accuracy and repeatability. Next, we measured CEP geometry across a larger sample set and correlated CEP geometric parameters to age, disc degeneration, level, and disc geometry. The MRI-based measures resulted in thicknesses (0.3-1 mm) that are comparable to prior measurements of CEP thickness. CEP thickness was greatest at the anterior/posterior (A/P) margins and smallest in the center. The CEP A/P thickness, axial area, and lateral width decreased with age but were not related to disc degeneration. Age-related, but not degeneration-related, changes in geometry suggest that the CEP may not follow the progression of disc degeneration. Ultimately, if the CEP undergoes significant geometric changes with aging and if these can be related to low back pain, a clinically feasible translation of the FLASH MRI-based measurement of CEP geometry presented in this study may prove a useful diagnostic tool. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1410-1417, 2016.

  3. Correlation of sea level falls interpreted from atoll stratigraphy with turbidites in adjacent basins

    SciTech Connect

    Lincoln, J.M. )

    1990-05-01

    Past sea levels can be derived from any atoll subsurface sediments deposited at or near sea level by determining the ages of deposition and correcting the present depths to the sediments for subsidence of the underlying edifice since the times of deposition. A sea level curve constructed by this method consists of discontinuous segments, each corresponding to a period of rising relative sea level and deposition of a discrete sedimentary package. Discontinuities in the sea level curve derived by this method correspond to relative sea level falls and stratigraphic hiatuses in the atoll subsurface. During intervals of relative sea level fall an atoll emerges to become a high limestone island. Sea level may fluctuate several times during a period of atoll emergence to become a high limestone island. Sea level may fluctuate several times during a period of atoll emergence without depositing sediments on top of the atoll. Furthermore, subaerial erosion may remove a substantial part of the depositional record of previous sea level fluctuations. For these reasons the authors must look to the adjacent basins to complement the incomplete record of sea level change recorded beneath atolls. During lowstands of sea level, faunas originally deposited near sea level on an atoll may be eroded and redeposited as turbidites in deep adjacent basins. Three such turbidites penetrated during deep-sea drilling at Sites 462 and 315 in the central Pacific correlate well with a late Tertiary sea level curve based on biostratigraphic ages and {sup 87}Sr/{sup 86}Sr chronostratigraphy for core from Enewetak Atoll in the northern Marshall Islands. Further drilling of the archipelagic aprons adjacent to atolls will improve the sea level history that may be inferred from atoll stratigraphy.

  4. The Effects of Single-Level Instrumented Lumbar Laminectomy on Adjacent Spinal Biomechanics

    PubMed Central

    Bisschop, Arno; Holewijn, Roderick M.; Kingma, Idsart; Stadhouder, Agnita; Vergroesen, Pieter-Paul A.; van der Veen, Albert J.; van Dieën, Jaap H.; van Royen, Barend J.

    2014-01-01

    Study Design Biomechanical study. Objective Posterior instrumentation is used to stabilize the spine after a lumbar laminectomy. However, the effects on the adjacent segmental stability are unknown. Therefore, we studied the range of motion (ROM) and stiffness of treated lumbar spinal segments and cranial segments after a laminectomy and after posterior instrumentation in flexion and extension (FE), lateral bending (LB), and axial rotation (AR). These outcomes might help to better understand adjacent segment disease (ASD), which is reported cranial to the level on which posterior instrumentation is applied. Methods We obtained 12 cadaveric human lumbar spines. Spines were axially loaded with 250 N for 1 hour. Thereafter, 10 consecutive load cycles (4 Nm) were applied in FE, LB, and AR. Subsequently, a laminectomy was performed either at L2 or at L4. Thereafter, load-deformation tests were repeated, after similar preloading. Finally, posterior instrumentation was added to the level treated with a laminectomy before testing was repeated. The ROM and stiffness of the treated, the cranial adjacent, and the control segments were calculated from the load-displacement data. Repeated-measures analyses of variance used the spinal level as the between-subject factor and a laminectomy or instrumentation as the within-subject factors. Results After the laminectomy, the ROM increased (+19.4%) and the stiffness decreased (−18.0%) in AR. The ROM in AR of the adjacent segments also increased (+11.0%). The ROM of treated segments after instrumentation decreased in FE (−74.3%), LB (−71.6%), and AR (−59.8%). In the adjacent segments after instrumentation, only the ROM in LB was changed (−12.9%). Conclusions The present findings do not substantiate a biomechanical pathway toward or explanation for ASD. PMID:25649753

  5. Good Functional Outcome and Adjacent Segment Disc Quality 10 Years after Single-Level Anterior Lumbar Interbody Fusion with Posterior Fixation

    PubMed Central

    Horsting, Philip P.; Pavlov, Paul W.; Jacobs, Wilco C.H.; Obradov-Rajic, Marina; de Kleuver, Marinus

    2012-01-01

    We reviewed the records of a prospective consecutive cohort to evaluate the clinical performance of anterior lumbar interbody fusion with a titanium box cage and posterior fixation, with emphasis on long-term functional outcome. Thirty-two patients with chronic low back pain underwent anterior lumbar interbody fusion and posterior fixation. Radiological and functional results (visual analogue scale [VAS] and Oswestry score) were evaluated. Adjacent segment degeneration (ASD) was evaluated radiologically and by magnetic resonance imaging (MRI). Twenty-five patients (78%) were available for follow-up. Functional scores showed significant improvement in pain and function up to the 2-year follow-up observation. At 4 years, there was some deterioration of the clinical results. At 10-year follow-up, results remained stable compared with 4-year results. MRI showed ASD in 3/25 (12%) above and 2/10 (20%) below index level (compared with absent preoperatively). ASD could not be related to clinical outcome in this study. Anterior lumbar interbody fusion and posterior fixation is safe and effective. Initial improvement in VAS and Oswestry scores is partly lost at the 4-year follow-up. Good clinical results are maintained at 10-year follow-up and are not related to adjacent segment degeneration. PMID:24353942

  6. Cascading Adjacent Level Vertebral Compression Fractures Necessitating a Series of Eleven Kyphoplasties.

    PubMed

    Curatolo, Evan; Reuter, Matthew; Samad, Adil; Flynn, Daniel; Menkowitz, Marc; Paragioudakis, Steve

    2015-01-01

    Vertebral kyphoplasty is a procedure used for the treatment of compression fractures. While early randomized-controlled trials were equivocal regarding its benefits, more recent RCTs have shown favorable results for kyphoplasty with regard to pain relief, functional recovery, and health-care related quality of life compared to control patients. Risks of kyphoplasty include but are not limited to cement extrusion, infection, hematoma, and vertebral body fracture of adjacent levels. We describe a case of a 66-year-old male attorney who underwent eleven kyphoplasties in an approximately one-year period, the majority of which were for fractures of vertebrae adjacent to those previously treated with kyphoplasty. Information on treatment was gathered from the patient's hospital chart and outpatient office notes. Following the last of the eleven kyphoplasties (two at T8, one each at all vertebrae from T9 to L5), the patient was able to function without pain and return to work. His physiologic thoracic kyphosis of 40 degrees prior to the first procedure was maintained, as were his lung and abdominal volumes. We conclude that kyphoplasty is an appropriate procedure for the treatment of vertebral compression fractures and can be used repeatedly to address fractures of levels adjacent to a previous kyphoplasty. PMID:26509091

  7. Yang-Mills amplitude relations at loop level from non-adjacent BCFW shifts

    NASA Astrophysics Data System (ADS)

    Boels, Rutger H.; Isermann, Reinke Sven

    2012-03-01

    This article studies methods to obtain relations for scattering amplitudes at the loop level, with concrete examples at one loop. These methods originate in the analysis of large so-called Britto-Cachazo-Feng-Witten shifts of tree level amplitudes and loop level integrands. In particular BCFW shifts for particles which are not color adjacent and some particular generalizations of this situation are analyzed in some detail in four and higher dimensions. For generic non-adjacent shifts our results are independent of loop order for integrands and hold for generic minimally coupled gauge theories with possible scalar potential and Yukawa terms. By a standard argument this result indicates a generalization of the Bern-Carrasco-Johansson relations for tree level amplitudes exists to the integrand at all loop levels. A concrete relation is presented at one loop. Furthermore, inspired by results in QED it is shown that the results on generalized BCFW shifts of tree level amplitudes imply relations for the so-called rational, bubble and triangle terms of one loop amplitudes in pure Yang-Mills theory. Bubble and triangle terms for instance are shown to obey a five photon decoupling identity, while a three photon decoupling identity is demonstrated for the rational terms. Along the same lines recently conjectured relations for helicity equal amplitudes at one loop are shown to generalize to helicity independent relations for the massive box coefficient of the rational terms.

  8. Spontaneous Regression of Herniated Lumbar Disc with New Disc Protrusion in the Adjacent Level

    PubMed Central

    Gürcan, Serkan

    2016-01-01

    Spontaneous regression of herniated lumbar discs was reported occasionally. The mechanisms proposed for regression of disc herniation are still incomplete. This paper describes and discusses a case of spontaneous regression of herniated lumbar discs with a new disc protrusion in the adjacent level. A 41-year-old man was admitted with radiating pain and numbness in the left lower extremity with a left posterolateral disc extrusion at L5-S1 level. He was admitted to hospital with low back pain due to disc herniation caudally immigrating at L4-5 level three years ago. He refused the surgical intervention that was offered and was treated conservatively at that time. He had no neurological deficit and a history of spontaneous regression of the extruded lumbar disc; so, a conservative therapy, including bed rest, physical therapy, nonsteroidal anti-inflammatory drugs, and analgesics, was advised. In conclusion, herniated lumbar disc fragments may regress spontaneously. Reports are prone to advise conservative treatment for extruded or sequestrated lumbar disc herniations. However, these patients should be followed up closely; new herniation at adjacent/different level may occur. Furthermore, it is important to know which herniated disk should be removed and which should be treated conservatively, because disc herniation may cause serious complications as muscle weakness and cauda equine syndrome. PMID:27429818

  9. Spontaneous Regression of Herniated Lumbar Disc with New Disc Protrusion in the Adjacent Level.

    PubMed

    Hakan, Tayfun; Gürcan, Serkan

    2016-01-01

    Spontaneous regression of herniated lumbar discs was reported occasionally. The mechanisms proposed for regression of disc herniation are still incomplete. This paper describes and discusses a case of spontaneous regression of herniated lumbar discs with a new disc protrusion in the adjacent level. A 41-year-old man was admitted with radiating pain and numbness in the left lower extremity with a left posterolateral disc extrusion at L5-S1 level. He was admitted to hospital with low back pain due to disc herniation caudally immigrating at L4-5 level three years ago. He refused the surgical intervention that was offered and was treated conservatively at that time. He had no neurological deficit and a history of spontaneous regression of the extruded lumbar disc; so, a conservative therapy, including bed rest, physical therapy, nonsteroidal anti-inflammatory drugs, and analgesics, was advised. In conclusion, herniated lumbar disc fragments may regress spontaneously. Reports are prone to advise conservative treatment for extruded or sequestrated lumbar disc herniations. However, these patients should be followed up closely; new herniation at adjacent/different level may occur. Furthermore, it is important to know which herniated disk should be removed and which should be treated conservatively, because disc herniation may cause serious complications as muscle weakness and cauda equine syndrome. PMID:27429818

  10. Diagrammatic treatment of coherent backscattering of intense light by cold atoms with degenerate energy levels

    NASA Astrophysics Data System (ADS)

    Shatokhin, V. N.; Blattmann, R.; Wellens, T.; Buchleitner, A.

    2014-08-01

    We present a generalization of the diagrammatic pump-probe approach to coherent backscattering (CBS) of intense laser light for atoms with degenerate energy levels. We employ this approach for a characterization of the double-scattering signal from optically pumped atoms with the transition Jg→Je=Jg+1 in the helicity-preserving polarization channel. We show that, in the saturation regime, the internal degeneracy becomes manifest for atoms with Jg≥1, leading to a faster decrease of the CBS enhancement factor with increasing saturation parameter than in the nondegenerate case.

  11. MSC response to pH levels found in degenerating intervertebral discs

    SciTech Connect

    Wuertz, Karin Godburn, Karolyn; Iatridis, James C.

    2009-02-20

    Painful degenerative disc disease is a major health problem and for successful tissue regeneration, MSCs must endure and thrive in a harsh disc microenvironment that includes matrix acidity as a critical factor. MSCs were isolated from bone marrow of Sprague-Dawley rats from two different age groups (<1 month, n = 6 and 4-5 months, n = 6) and cultured under four different pH conditions representative of the healthy, mildly or severely degenerated intervertebral disc (pH 7.4, 7.1, 6.8, and 6.5) for 5 days. Acidity caused an inhibition of aggrecan, collagen-1, and TIMP-3 expression, as well as a decrease in proliferation and viability and was associated with a change in cell morphology. Ageing had generally minor effects but young MSCs maintained greater mRNA expression levels. As acidic pH levels are typical of increasingly degenerated discs, our findings demonstrate the importance of early interventions and predifferentiation when planning to use MSCs for reparative treatments.

  12. Nonlinear optical susceptibility of EIT systems with a degenerate Rydberg level

    NASA Astrophysics Data System (ADS)

    Stanojevic, Jovica; Grangier, Philippe; Côté, Robin

    2016-06-01

    It has been demonstrated that very large optical nonlinearities can arise in cold Rydberg gases from strong Rydberg–Rydberg interactions. The interactions between atoms excited to a degenerate Rydberg level are described by a large number of molecular potentials which greatly complicates the theoretical treatment of these systems. We here present a method for very accurate calculation of the third order interaction-induced optical nonlinearities that fully includes the angle-dependent mixing of molecular states by the control optical field. In addition, we investigate how an effective potential can be introduced to describe the third-order optical susceptibility arising from the underlying multi-potential Rydberg–Rydberg interactions. We show that a single effective potential can replace a manifold of asymptotically degenerate potentials of the same sign. Therefore, one effective potential has to be defined for attractive interactions and another for repulsive ones. As an example, we have calculated effective C 6 coefficients of nd + nd asymptotes of rubidium and cesium. We compare accurately calculated collisional integrals with those obtained using effective potentials.

  13. Nonlinear optical susceptibility of EIT systems with a degenerate Rydberg level

    NASA Astrophysics Data System (ADS)

    Stanojevic, Jovica; Grangier, Philippe; Côté, Robin

    2016-06-01

    It has been demonstrated that very large optical nonlinearities can arise in cold Rydberg gases from strong Rydberg-Rydberg interactions. The interactions between atoms excited to a degenerate Rydberg level are described by a large number of molecular potentials which greatly complicates the theoretical treatment of these systems. We here present a method for very accurate calculation of the third order interaction-induced optical nonlinearities that fully includes the angle-dependent mixing of molecular states by the control optical field. In addition, we investigate how an effective potential can be introduced to describe the third-order optical susceptibility arising from the underlying multi-potential Rydberg-Rydberg interactions. We show that a single effective potential can replace a manifold of asymptotically degenerate potentials of the same sign. Therefore, one effective potential has to be defined for attractive interactions and another for repulsive ones. As an example, we have calculated effective C 6 coefficients of nd + nd asymptotes of rubidium and cesium. We compare accurately calculated collisional integrals with those obtained using effective potentials.

  14. Temporal buildup of electromagnetically induced transparency and absorption resonances in degenerate two-level transitions

    NASA Astrophysics Data System (ADS)

    Valente, P.; Failache, H.; Lezama, A.

    2003-01-01

    The temporal evolution of electromagnetically induced transparency (EIT) and absorption (EIA) coherence resonances in pump-probe spectroscopy of degenerate two-level atomic transition is studied for light intensities below saturation. Analytical expressions for the transient absorption spectra are given for simple model systems and a model for the calculation of the time-dependent response of realistic atomic transitions, where the Zeeman degeneracy is fully accounted for, is presented. EIT and EIA resonances have a similar (opposite sign) time-dependent line shape, however, the EIA evolution is slower and thus narrower lines are observed for long interaction time. Qualitative agreement with the theoretical predictions is obtained for the transient probe absorption on the 85Rb D2 line in an atomic beam experiment.

  15. The Association between the Lipids Levels in Blood and Risk of Age-Related Macular Degeneration

    PubMed Central

    Wang, Yafeng; Wang, Mingxu; Zhang, Xiaoqing; Zhang, Qianyu; Nie, Jing; Zhang, Ming; Liu, Xiaohong; Ma, Le

    2016-01-01

    Lipid metabolism may be involved in the pathogenic mechanism of age-related macular degeneration (AMD). However, conflicting results have been reported in the associations of AMD with blood lipids. We performed a meta-analysis including a total of 19 studies to evaluate associations between blood lipids and this disease. The result reported that the high level of high-density lipoprotein cholesterol (HDL-C) obtained with an increment of 1 mmol/L could result in a significantly increase in the AMD risk of approximately 18% (relative risk (RR), 1.18; 95% confidence interval (CI), 1.01 to 1.35; I2 = 53.8%; p = 0.007). High levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG) were significantly associated with a decreased risk of AMD (RRs ranging from 0.92 to 0.95; all p < 0.05). The stratified analysis based on AMD subtypes showed that these blood lipids were only significantly associated with the risk of early AMD (all p < 0.05). The association between the blood lipids and AMD risk did not differ substantially based on the other characteristics of the participants. A high HDL-C level was associated with an increased AMD risk, whereas participants with high TC, LDL-C, and TG concentrations may show a decreased risk for this disease. Further well-designed large studies are warranted to confirm the conclusions. PMID:27782072

  16. Theory for magnetic linear dichroism of electronic transitions between twofold-degenerate molecular spin levels

    NASA Astrophysics Data System (ADS)

    Bominaar, Emile L.; Achim, Catalina; Peterson, Jim

    1998-07-01

    Magnetic linear dichroism (MLD) spectroscopy is a relatively new technique which previously has been almost exclusively applied to atoms. These investigations have revealed that the study of MLD, in conjunction with electronic absorption and magnetic circular dichroism (MCD) spectroscopies, provides significant additional information concerning the electronic structure of atoms. More recent measurements have indicated that MLD is also observable from transition ions in inorganic compounds and metalloproteins. While the theory for atomic MLD has been worked out in considerable detail during the last two decades, an MLD theory of practical utility for the analysis of the spectra derived from the majority of paramagnetic molecules is not available. In the present contribution, the MLD of an electric-dipole-allowed transition between twofold-degenerate molecular spin levels is analyzed, assuming nonsaturating conditions. As for atomic systems, it is found that the MLD of a single molecule is dominated by the term G0. However, this term vanishes in the powder average evaluated for a randomly oriented ensemble of molecules, leading to a drastic reduction of the MLD differential absorption for systems with spin S=1/2 compared to that observed for systems with higher ground-state spin. It is found that MLD and MCD spectroscopies on solution samples have complementary spin-state specific sensitivities which suggest that the two methods can be used to selectively probe the individual metal sites in multicenter metalloprotein assemblies.

  17. Adjacent-Level Hypermobility and Instrumented-Level Fatigue Loosening With Titanium and PEEK Rods for a Pedicle Screw System: An In Vitro Study.

    PubMed

    Agarwal, Aakas; Ingels, Marcel; Kodigudla, Manoj; Momeni, Narjes; Goel, Vijay; Agarwal, Anand K

    2016-05-01

    Adjacent-level disease is a common iatrogenic complication seen among patients undergoing spinal fusion for low back pain. This is attributed to the postsurgical differences in stiffness between the spinal levels, which result in abnormal forces, stress shielding, and hypermobility at the adjacent levels. In addition, as most patients undergoing these surgeries are osteoporotic, screw loosening at the index level is a complication that commonly accompanies adjacent-level disease. Recent studies indicate that a rod with lower rigidity than that of titanium may help to overcome these detrimental effects at the adjacent level. The present study was conducted in vitro using 12 L1-S1 specimens divided into groups of six, with each group instrumented with either titanium rods or PEEK (polyetheretherketone) rods. The test protocol included subjecting intact specimens to pure moments of 10 Nm in extension and flexion using an FS20 Biomechanical Spine Test System (Applied Test Systems) followed by hybrid moments on the instrumented specimens to achieve the same L1-S1 motion as that of the intact specimens. During the protocol's later phase, the L4-L5 units from each specimen were segmented for cyclic loading followed by postfatigue kinematic analysis to highlight the differences in motion pre- and postfatigue. The objectives included the in vitro comparison of (1) the adjacent-level motion before and after instrumentation with PEEK and titanium rods and (2) the pre- and postfatigue motion at the instrumented level with PEEK and titanium rods. The results showed that the adjacent levels above the instrumentation caused increased flexion and extension with both PEEK and titanium rods. The postfatigue kinematic data showed that the motion at the instrumented level (L4-L5) increased significantly in both flexion and extension compared to prefatigue motion in titanium groups. However, there was no significant difference in motion between the pre- and postfatigue data in the PEEK

  18. Pump-probe spectroscopy in degenerate two-level atoms with arbitrarily strong fields

    NASA Astrophysics Data System (ADS)

    Zigdon, T.; Wilson-Gordon, A. D.; Goren, C.; Rosenbluh, M.; Friedmann, H.

    2007-03-01

    We review our previous work on pump-probe spectroscopy in realistic degenerate two-level systems and model systems. In particular, we discuss the role of transfer of coherence (TOC) between the ground and excited hyperfine states in producing electromagnetically-induced transparency (EIA) peaks in the probe spectrum, when an F g goes to F e = F g +1 transition in an alkali-metal atom interacts with a strong pump and weak probe that have perpendicular polarizations. When the pump is rho + polarized and the probe pi polarized, this system can be modelled by an N system. We also discuss the role of transfer of population (TOP) between the Zeeman levels of the ground hyperfine state in producing EIA peaks when the pump and probe have the same polarization. This system can be modelled using a double two-level system. The role of Doppler broadening and phase-changing collisions in modifying the EIA-TOC and EIA-TOP absorption and refraction spectra is also discussed. All these spectra were calculated using MATLAB programs that both construct and solve the relevant Bloch equations. In our recent work, we consider the effect of a strong probe on the pump absorption and refraction spectra when the pump and probe polarizations are linear and perpendicular. It is difficult to solve this problem numerically due to the large number frequencies involved. In order to simplify the problem, we considered two cases: (i) rho + polarized pump and pi polarized probe, and (ii) rho + polarized pump and rho - polarized probe, and investigated a series of transitions in both Rb and Cs, using modified versions of the MATLAB programs devised for the weakprobe case. A number of interesting differences from the weak-probe case were found. For example, when the probe is sufficiently strong, we found the pump and probe spectra to show complementary behavior. In addition, as the number of Zeeman levels increase, the EIA peaks become progressively sharper, and are accompanied by steeper dispersion.

  19. Biomechanical performance of rigid compared to dynamic anterior cervical plating: analysis of adjacent upper and lower level compressive forces.

    PubMed

    Connor, David E; Shamieh, Khader Samer; Ogden, Alan L; Mukherjee, Debi P; Sin, Anthony; Nanda, Anil

    2012-12-01

    Dynamic anterior cervical plating is well established as a means of enhancing graft loading and subsequent arthrodesis. Current concerns center on the degree of adjacent-level stress induced by these systems. The aim of this study was to evaluate and compare the load transferred to adjacent levels for single-level anterior cervical discectomy and fusion utilizing rigid compared to dynamic anterior plating systems. Nine cadaveric adult human cervical spine specimens were subjected to range-of-motion testing prior to and following C5-C6 anterior cervical discectomy and fusion procedures. Interbody grafting was performed with human fibula tissue. Nondestructive biomechanical testing included flexion/extension and lateral bending loading modes. A constant displacement of 5mm was applied in each direction and the applied load was measured in newtons (N). Specimens were tested in the following order: intact, following discectomy, after rigid plating, then after dynamic plating. Adjacent level (C4-C5 [L(S)] and C6-C7 [L(I)]) compressive forces were measured using low profile load cells inserted into each disc space. The measured load values for plating systems were then normalized using values measured for the intact specimens. Mean loads transferred to L(S) and L(I) during forced flexion in specimens with rigid plating were 23.47 N and 8.76 N, respectively; while the corresponding values in specimens with dynamic plating were 18.55 N and 1.03 N, respectively. Dynamic plating yielded no significant change at L(I) and a 21.0% decrease in load at L(S) when compared with rigid plating, although the difference was not significant. The observed trend suggests that dynamic plating may diminish superior adjacent level compressive stresses.

  20. Analysis of adjacent segment reoperation after lumbar total disc replacement

    PubMed Central

    Rainey, Scott; Blumenthal, Scott L.; Zigler, Jack E.; Guyer, Richard D.; Ohnmeiss, Donna D.

    2012-01-01

    Background Fusion has long been used for treating chronic back pain unresponsive to nonoperative care. However, potential development of adjacent segment degeneration resulting in reoperation is a concern. Total disc replacement (TDR) has been proposed as a method for addressing back pain and preventing or reducing adjacent segment degeneration. The purpose of the study was to determine the reoperation rate at the segment adjacent to a level implanted with a lumbar TDR and to analyze the pre-TDR condition of the adjacent segment. Methods This study was based on a retrospective review of charts and radiographs from a consecutive series of 1000 TDR patients to identify those who underwent reoperation because of adjacent segment degeneration. Some of the patients were part of randomized studies comparing TDR with fusion. Adjacent segment reoperation data were also collected from 67 patients who were randomized to fusion in those studies. The condition of the adjacent segment before the index surgery was compared with its condition before reoperation based on radiographs, magnetic resonance imaging (MRI), and computed tomography. Results Of the 1000 TDR patients, 20 (2.0%) underwent reoperation. The mean length of time from arthroplasty to reoperation was 28.3 months (range, 0.5–85 months). Of the adjacent segments evaluated on preoperative MRI, 38.8% were normal, 38.8% were moderately diseased, and 22.2% were classified as having severe degeneration. None of these levels had a different grading at the time of reoperation compared with the pre-TDR MRI study. Reoperation for adjacent segment degeneration was performed in 4.5% of the fusion patients. Conclusions The 2.0% rate of adjacent segment degeneration resulting in reoperation in this study is similar to the 2.0% to 2.8% range in other studies and lower than the published rates of 7% to 18% after lumbar fusion. By carefully assessing the presence of pre-existing degenerative changes before performing arthroplasty

  1. Adjacent Segment Disease Perspective and Review of the Literature

    PubMed Central

    Saavedra-Pozo, Fanor M.; Deusdara, Renato A. M.; Benzel, Edward C.

    2014-01-01

    Background Adjacent segment disease has become a common topic in spine surgery circles because of the significant increase in fusion surgery in recent years and the development of motion preservation technologies that theoretically should lead to a decrease in this pathology. The purpose of this review is to organize the evidence available in the current literature on this subject. Methods For this literature review, a search was conducted in PubMed with the following keywords: adjacent segment degeneration and disease. Selection, review, and analysis of the literature were completed according to level of evidence. Results The PubMed search identified 850 articles, from which 41 articles were selected and reviewed. The incidence of adjacent segment disease in the cervical spine is close to 3% without a significant statistical difference between surgical techniques (fusion vs arthroplasty). Authors report the incidence of adjacent segment disease in the lumbar spine to range from 2% to 14%. Damage to the posterior ligamentous complex and sagittal imbalances are important risk factors for both degeneration and disease. Conclusion Insufficient evidence exists at this point to support the idea that total disc arthroplasty is superior to fusion procedures in minimizing the incidence of adjacent segment disease. The etiology is most likely multifactorial but it is becoming abundantly clear that adjacent segment disease is not caused by motion segment fusion alone. Fusion plus the presence of abnormal end-fusion alignment appears to be a major factor in creating end-fusion stresses that result in adjacent segment degeneration and subsequent disease. The data presented cast further doubt on previously established rationales for total disc arthroplasty, at least with regard to the effect of total disc arthroplasty on adjacent segment degeneration pathology. PMID:24688337

  2. Trabecular angle of the human talus is associated with the level of cartilage degeneration.

    PubMed

    Schiff, A; Li, J; Inoue, N; Masuda, K; Lidtke, R; Muehleman, C

    2007-01-01

    The architecture of bone trabeculae is based on the direction of stresses applied to the bone. The human talar dome receives compressive forces from the tibia and, to a much lesser extent, the fibula when standing, walking, and running, and transmits the force downward to the calcaneus through the talar body and anterior to the navicular via the talar head. As a result, the body of the talus has predominately vertical trabeculae. However, here we hypothesize that cartilage degeneration at the articular surface is associated with trabecular angle within the associated bone, as a reflection of joint alignment and/or biomechanics (stability, congruence, angulation, etc). Through measurement of trabecular angle with Fast Fourier Transform Analysis, we show a positive correlation between the cartilage degeneration score of the articular surface of the talar dome and the angle of trabecular deviation from the perpendicular axis of the dome (right talus R=0.75, p<0.01; left talus R=0.79, p<0.01).

  3. Historical change and future scenarios of sea level rise in Macau and adjacent waters

    NASA Astrophysics Data System (ADS)

    Wang, Lin; Huang, Gang; Zhou, Wen; Chen, Wen

    2016-04-01

    Against a background of climate change, Macau is very exposed to sea level rise (SLR) because of its low elevation, small size, and ongoing land reclamation. Therefore, we evaluate sea level changes in Macau, both historical and, especially, possible future scenarios, aiming to provide knowledge and a framework to help accommodate and protect against future SLR. Sea level in Macau is now rising at an accelerated rate: 1.35 mm yr-1 over 1925-2010 and jumping to 4.2 mm yr-1 over 1970-2010, which outpaces the rise in global mean sea level. In addition, vertical land movement in Macau contributes little to local sea level change. In the future, the rate of SLR in Macau will be about 20% higher than the global average, as a consequence of a greater local warming tendency and strengthened northward winds. Specifically, the sea level is projected to rise 8-12, 22-51 and 35-118 cm by 2020, 2060 and 2100, respectively, depending on the emissions scenario and climate sensitivity. Under the +8.5 W m-2 Representative Concentration Pathway (RCP8.5) scenario the increase in sea level by 2100 will reach 65-118 cm—double that under RCP2.6. Moreover, the SLR will accelerate under RCP6.0 and RCP8.5, while remaining at a moderate and steady rate under RCP4.5 and RCP2.6. The key source of uncertainty stems from the emissions scenario and climate sensitivity, among which the discrepancies in SLR are small during the first half of the 21st century but begin to diverge thereafter.

  4. Residual degeneracy from non-degenerate Landau levels of ultracold atoms in light-induced gauge potentials

    NASA Astrophysics Data System (ADS)

    Farias, B.; Melo, J. Lemos de; Furtado, C.

    2016-10-01

    We study non-degenerate Landau levels of ultracold trapped atoms in two dimensions, subject to an U (1) × U(1) Abelian gauge field and a lateral confining potential along a specific direction. The Landau-level degeneracy is removed due to the presence of the lateral confining potential that makes the single-particle energy spectrum explicitly dependent on the transverse momentum. The effect of the finite size of the atomic cloud on the energy spectrum is to split each Landau level into a set of sub-levels, once the transverse momentum becomes quantized. We show that under appropriate conditions some energy sub-levels overlap leading to a residual degeneracy of the system. Through numerical calculations, we map the residual degeneracy as a function of the effective magnetic field strength. Finally, we briefly discuss future studies on the transport properties of this atomic system that can be considered an optically induced atomic waveguide.

  5. Effective collision strengths for optically allowed transitions among degenerate levels of hydrogenic ions with 2{<=}Z{<=}30

    SciTech Connect

    Hamada, K.; Aggarwal, K.M.; Akita, K.; Igarashi, A.; Keenan, F.P.; Nakazaki, S.

    2010-09-15

    The Coulomb-Born approximation is used to calculate electron-impact excitation collision strengths and effective collision strengths for optically allowed transitions among degenerate fine-structure levels of hydrogenic ions with 2{<=}Z{<=}30 and n{<=}5. Collision strengths are calculated over a wide range of energies up to E{sub j}/Z{sup 2}=10Ryd. Effective collision strengths are obtained over a wide temperature range up to 10{sup 8}K by integrating the collision strengths over a Maxwellian distribution of electron velocities.

  6. Macular degeneration

    MedlinePlus

    ... at the center of the field of vision. Macular degeneration results from a partial breakdown of the insulating ... choroid layer of blood vessels behind the retina. Macular degeneration results in the loss of central vision only.

  7. Cerebellar Degeneration

    MedlinePlus

    ... Degeneration? Cerebellar degeneration is a process in which neurons in the cerebellum - the area of the brain ... proteins that are necessary for the survival of neurons. Associated diseases: Diseases that are specific to the ...

  8. Adjacent segment disease.

    PubMed

    Virk, Sohrab S; Niedermeier, Steven; Yu, Elizabeth; Khan, Safdar N

    2014-08-01

    EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Understand the forces that predispose adjacent cervical segments to degeneration. 2. Understand the challenges of radiographic evaluation in the diagnosis of cervical and lumbar adjacent segment disease. 3. Describe the changes in biomechanical forces applied to adjacent segments of lumbar vertebrae with fusion. 4. Know the risk factors for adjacent segment disease in spinal fusion. Adjacent segment disease (ASD) is a broad term encompassing many complications of spinal fusion, including listhesis, instability, herniated nucleus pulposus, stenosis, hypertrophic facet arthritis, scoliosis, and vertebral compression fracture. The area of the cervical spine where most fusions occur (C3-C7) is adjacent to a highly mobile upper cervical region, and this contributes to the biomechanical stress put on the adjacent cervical segments postfusion. Studies have shown that after fusion surgery, there is increased load on adjacent segments. Definitive treatment of ASD is a topic of continuing research, but in general, treatment choices are dictated by patient age and degree of debilitation. Investigators have also studied the risk factors associated with spinal fusion that may predispose certain patients to ASD postfusion, and these data are invaluable for properly counseling patients considering spinal fusion surgery. Biomechanical studies have confirmed the added stress on adjacent segments in the cervical and lumbar spine. The diagnosis of cervical ASD is complicated given the imprecise correlation of radiographic and clinical findings. Although radiological and clinical diagnoses do not always correlate, radiographs and clinical examination dictate how a patient with prolonged pain is treated. Options for both cervical and lumbar spine ASD include fusion and/or decompression. Current studies are encouraging regarding the adoption of arthroplasty in spinal surgery, but more long

  9. Pegaptanib sodium as maintenance therapy in neovascular age-related macular degeneration: the LEVEL study

    PubMed Central

    Tolentino, Michael

    2010-01-01

    Aim To assess the efficacy of pegaptanib as maintenance therapy in neovascular age-related macular degeneration (NV-AMD) patients after induction therapy. Methods A phase IV, prospective, open-label, uncontrolled exploratory study including subjects with subfoveal NV-AMD who had had one to three induction treatments 30–120 days before entry and showed investigator-determined clinical/anatomical NV-AMD improvement. Lesions in the study eye were: any subtype, 12 or fewer disc areas; postinduction centre point thickness (CPT) 275 μm or less or thinning of 100 μm or more (optical coherence tomography); visual acuity (VA) 20/20–20/400. Intravitreal pegaptanib 0.3 mg was administered as maintenance every 6 weeks for 48 weeks with follow-up to week 54. Booster treatment additional unscheduled treatment for wet age-related macular degeneration, was allowed in the study eye at the investigators' discretion for clinical deterioration. Results Of 568 enrolled subjects, 86% completed 1 year of pegaptanib. Mean VA improvement during induction (49.6 to 65.5 letters) was well preserved (54-week mean 61.8 letters). Mean CPT was relatively stable during maintenance (20 μm increase during the study). Fifty per cent did not receive unscheduled booster treatment to week 54; 46% did have one such booster (mean 147 days after maintenance initiation). Conclusions An induction-maintenance strategy, using non-selective then selective vascular endothelial growth factor (VEGF) inhibitors, could be considered for NV-AMD. This approach may have particular relevance for patients with systemic comorbidities who require long-term anti-VEGF therapy for NV-AMD. PMID:20472746

  10. Defective Tapetum Cell Death 1 (DTC1) Regulates ROS Levels by Binding to Metallothionein during Tapetum Degeneration.

    PubMed

    Yi, Jakyung; Moon, Sunok; Lee, Yang-Seok; Zhu, Lu; Liang, Wanqi; Zhang, Dabing; Jung, Ki-Hong; An, Gynheung

    2016-03-01

    After meiosis, tapetal cells in the innermost anther wall layer undergo program cell death (PCD)-triggered degradation. This step is essential for microspore development and pollen wall maturation. We identified a key gene, Defective Tapetum Cell Death 1 (DTC1), that controls this degeneration by modulating the dynamics of reactive oxygen species (ROS) during rice male reproduction. Mutants defective in DTC1 exhibit phenotypes of an enlarged tapetum and middle layer with delayed degeneration, causing male sterility. The gene is preferentially expressed in the tapetal cells during early anther development. In dtc1 anthers, expression of genes encoding secretory proteases or lipid transporters is significantly reduced, while transcripts of PCD regulatory genes, e.g. UDT1, TDR1, and EAT1/DTD, are not altered. Moreover, levels of DTC1 transcripts are diminished in udt1, tdr, and eat1 anthers. These results suggest that DTC1 functions downstream of those transcription factor genes and upstream of the genes encoding secretory proteins. DTC1 protein interacts with OsMT2b, a ROS scavenger. Whereas wild-type plants accumulate large amounts of ROS in their anthers at Stage 9 of development, those levels remain low during all stages of development in dtc1 anthers. These findings indicate that DTC1 is a key regulator for tapetum PCD by inhibiting ROS-scavenging activity. PMID:26697896

  11. Defective Tapetum Cell Death 1 (DTC1) Regulates ROS Levels by Binding to Metallothionein during Tapetum Degeneration1[OPEN

    PubMed Central

    Moon, Sunok; Lee, Yang-Seok; Zhu, Lu; Jung, Ki-Hong; An, Gynheung

    2016-01-01

    After meiosis, tapetal cells in the innermost anther wall layer undergo program cell death (PCD)-triggered degradation. This step is essential for microspore development and pollen wall maturation. We identified a key gene, Defective Tapetum Cell Death 1 (DTC1), that controls this degeneration by modulating the dynamics of reactive oxygen species (ROS) during rice male reproduction. Mutants defective in DTC1 exhibit phenotypes of an enlarged tapetum and middle layer with delayed degeneration, causing male sterility. The gene is preferentially expressed in the tapetal cells during early anther development. In dtc1 anthers, expression of genes encoding secretory proteases or lipid transporters is significantly reduced, while transcripts of PCD regulatory genes, e.g. UDT1, TDR1, and EAT1/DTD, are not altered. Moreover, levels of DTC1 transcripts are diminished in udt1, tdr, and eat1 anthers. These results suggest that DTC1 functions downstream of those transcription factor genes and upstream of the genes encoding secretory proteins. DTC1 protein interacts with OsMT2b, a ROS scavenger. Whereas wild-type plants accumulate large amounts of ROS in their anthers at Stage 9 of development, those levels remain low during all stages of development in dtc1 anthers. These findings indicate that DTC1 is a key regulator for tapetum PCD by inhibiting ROS-scavenging activity. PMID:26697896

  12. Assessment of the Relative Largest Earthquake Hazard Level in the NW Himalaya and its Adjacent Region

    NASA Astrophysics Data System (ADS)

    Tsapanos, Theodoros M.; Yadav, R. B. S.; Olasoglou, Efthalia M.; Singh, Mayshree

    2016-04-01

    In the present study, the level of the largest earthquake hazard is assessed in 28 seismic zones of the NW Himalaya and its vicinity, which is a highly seismically active region of the world. Gumbel's third asymptotic distribution (hereafter as GIII) is adopted for the evaluation of the largest earthquake magnitudes in these seismic zones. Instead of taking in account any type of Mmax, in the present study we consider the ω value which is the largest earthquake magnitude that a region can experience according to the GIII statistics. A function of the form Θ(ω, RP6.0) is providing in this way a relatively largest earthquake hazard scale defined by the letter K(K index). The return periods for the ω values (earthquake magnitudes) 6 or larger (RP6.0) are also calculated. According to this index, the investigated seismic zones are classified into five groups and it is shown that seismic zones 3 (Quetta of Pakistan), 11 (Hindukush), 15 (northern Pamirs), and 23 (Kangra, Himachal Pradesh of India) correspond to a "very high" K index which is 6.

  13. Altered Levels of Visinin-Like Protein 1 Correspond to Regional Neuronal Loss in Alzheimer Disease and Frontotemporal Lobar Degeneration.

    PubMed

    Kirkwood, Caitlin M; MacDonald, Matthew L; Schempf, Tadhg A; Vatsavayi, Anil V; Ikonomovic, Milos D; Koppel, Jeremy L; Ding, Ying; Sun, Mai; Kofler, Julia K; Lopez, Oscar L; Yates, Nathan A; Sweet, Robert A

    2016-02-01

    Recent studies have implicated the neuronal calcium-sensing protein visinin-like 1 protein (Vilip-1) as a peripheral biomarker in Alzheimer disease (AD), but little is known about expression of Vilip-1 in the brains of patients with AD. We used targeted and quantitative mass spectrometry to measure Vilip-1 peptide levels in the entorhinal cortex (ERC) and the superior frontal gyrus (SF) from cases with early to moderate stage AD, frontotemporal lobar degeneration (FTLD), and cognitively and neuropathologically normal elderly controls. We found that Vilip-1 levels were significantly lower in the ERC, but not in SF, of AD subjects compared to normal controls. In FTLD cases, Vilip-1 levels in the SF were significantly lower than in normal controls. These findings suggest a unique role for cerebrospinal fluid Vilip-1 as a biomarker of ERC neuron loss in AD.

  14. Extent of Disc Degeneration after Single-Level Cervical Anterior Microforaminotomy Analyzed with Long-Term Radiological Data

    PubMed Central

    Han, Chul

    2014-01-01

    Objective To prove the extents and details of cervical degeneration after anterior microforaminotomy (AMF) with 6-years follow-up. Methods A retrospective study of 24 patients, underwent single-level AMF, was performed. Clinical and radiologic data were analyzed with office charts, questionaires, and picture achieving and communication system images. Results According to Odom's criteria, 91.6% achieved favorable outcome. The mean visual analog scale score was improved from 8.6 to 3, and the mean neck disability index was improved from 27.9 to 7.3 (p<0.01). Eighteen cases (75%) showed disc height (DH) decrease. The disc invasion was correlated with DH decrease (p<0.05). The disc height decrease correlated with static, dynamic changes of shell angle and spur formation (p<0.05). Any radiological parameters did not affect the clinical outcome. Conclusion AMF is an effective technique for treating unilateral cervical radiculopathy. It showed excellent surgical outcomes even in long-term follow-ups. However, a decrease in DH occurred in a considerable number of patients. Disc invasion during surgery may be the trigger of sequential degeneration. PMID:25368761

  15. Cyclic nucleotides of cone-dominant retinas. Reduction of cyclic AMP levels by light and by cone degeneration.

    PubMed

    Farber, D B; Souza, D W; Chase, D G; Lolley, R N

    1981-01-01

    Dark-adapted retinas or whole eyes of 13-line ground squirrels (Citellus tridecemlineatus) and western fence lizards (Sceloporus occidentalis) contain higher levels of cyclic AMP than of cyclic GMP. In these cone-dominant retinas, light reduces cyclic AMP content selectively. Freezing of dark- or light-adapted retinas or eyes also reduces cyclic AMP content, with only minimal changes in cyclic GMP levels. In addition, exposure of frozen retinas of dark-adapted ground squirrel to light results in a significant decrease in cyclic AMP content. The destruction of cone visual cells of ground squirrel retina by iodoacetic acid injection decreases the cyclic nucleotide content of the dark-adapted retina. Considering the relative loss of cyclic nucleotides from cone degeneration, we estimate that the content of cyclic AMP in visual cells of ground squirrel retina is about four times greater than that of cyclic GMP. PMID:6256308

  16. Effects of Withdrawals on Ground-Water Levels in Southern Maryland and the Adjacent Eastern Shore, 1980-2005

    USGS Publications Warehouse

    Soeder, Daniel J.; Raffensperger, Jeff P.; Nardi, Mark R.

    2007-01-01

    Ground water is the primary source of water supply in most areas of Maryland?s Atlantic Coastal Plain, including Southern Maryland. The counties in this area are experiencing some of the most rapid growth and development in the State, resulting in an increased demand for ground-water production. The cooperative, basic water-data program of the U.S. Geological Survey and the Maryland Geological Survey has collected long-term observations of ground-water levels in Southern Maryland and parts of the Eastern Shore for many decades. Additional water-level observations were made by both agencies beginning in the 1970s, under the Power Plant Research Program of the Maryland Department of Natural Resources. These long-term water levels commonly show significant declines over several decades, which are attributed to ground-water withdrawals. Ground-water-level trends since 1980 in major Coastal Plain aquifers such as the Piney Point-Nanjemoy, Aquia, Magothy, upper Patapsco, lower Patapsco, and Patuxent were compared to water use and withdrawal data. Potentiometric surface maps show that most of the declines in ground-water levels can be directly related to effects from major pumping centers. There is also evidence that deep drawdowns in some pumped aquifers may be causing declines in adjacent, unpumped aquifers. Water-level hydrographs of many wells in Southern Maryland show linear declines in levels year after year, instead of the gradual leveling-off that would be expected as the aquifers equilibrate with pumping. A continual increase in the volumes of water being withdrawn from the aquifers is one explanation for why they are not reaching equilibrium. Although reported ground-water production in Southern Maryland has increased somewhat over the past several decades, the reported increases are often not large enough to account for the observed water-level declines. Numerical modeling simulations indicate that a steady, annual increase in the number of small wells could

  17. A Novel Complotype Combination Associates with Age-Related Macular Degeneration and High Complement Activation Levels in vivo

    PubMed Central

    Paun, Constantin C.; Lechanteur, Yara T. E.; Groenewoud, Joannes M. M.; Altay, Lebriz; Schick, Tina; Daha, Mohamed R.; Fauser, Sascha; Hoyng, Carel B.; den Hollander, Anneke I.; de Jong, Eiko K.

    2016-01-01

    The complement system is the first line of defense against foreign intruders, and deregulation of this system has been described in multiple diseases. In age-related macular degeneration (AMD), patients have higher complement activation levels compared to controls. Recently, a combination of three single nucleotide polymorphisms (SNPs) in genes of the complement system, referred to as a complotype, has been described to increase complement activation in vitro. Here we describe a novel complotype composed of CFB (rs4151667)-CFB (rs641153)-CFH (rs800292), which is strongly associated with both AMD disease status (p = 5.84*10−13) and complement activation levels in vivo (p = 8.31*10−9). The most frequent genotype combination of this complotype was associated with the highest complement activation levels in both patients and controls. These findings are relevant in the context of complement-lowering treatments for AMD that are currently under development. Patients with a genetic predisposition to higher complement activation levels will potentially benefit the most of such treatments. PMID:27241480

  18. Correlation of serum trace elements and melatonin levels to radiological, biochemical, and histological assessment of degeneration in patients with intervertebral disc herniation.

    PubMed

    Turgut, Mehmet; Yenisey, Cigdem; Akyüz, Orhan; Ozsunar, Yelda; Erkus, Muhan; Biçakçi, Tuncay

    2006-02-01

    The aim of our study was to assess the blood concentrations of some trace elements and melatonin (MLT) in patients with intervertebral disc herniation (IDH) and to investigate the interaction of histological and biochemical degeneration findings with aging. The present study was carried out on 13 subjects (8 women and 5 men) diagnosed with IDH. They were divided into three groups according to their ages. Nighttime serum MLT, zinc (Zn), and magnesium (Mg) levels were determined in all patients. In addition, computed tomography (CT) scan of the brain and magnetic resonance imaging examination of the lumbar spine were obtained in this study. The Zn level and Zn/Mg ratio showed a decline in patients with IDH with aging, whereas the serum Mg level and tissue hydroxyproline content increased. A positive correlation between serum Zn and MLT concentrations was found (r=0.104, p=0.734). In addition, there was a positive correlation between serum Zn level and Zn/Mg ratio (r=0.835 and p<0.01), and a negative correlation between serum Mg level and Zn/Mg ratio (r=-0.571, p<0.05). On CT study, both volume percentage of calcified pineal gland and density of calcification were found to increase progressively with advancing age. The results of semiquantitative evaluation of disc tissues of patients with IDH for histological degeneration findings showed that 66.7% of discs treated had slight degeneration in younger age group, but 75.0% and 100% of discs had moderate or marked degeneration in older age groups. Our data indicated that there is a close relationship between MLT and Zn or Mg levels in the serum samples of patients with IDH, and the levels of these elements might be affected by the presence of degeneration process and serum MLT level, or vice versa. PMID:16444002

  19. Electron correlation in the second Landau level: a competition between many, nearly degenerate quantum phases.

    SciTech Connect

    Vincente, C.L.; Pan, Wei; Stormer, H. L.; Sullivan, N. S.; Adams, E. D.; Xia, J. S.; West, Ken W.; Tsui, Daniel Chee; Pfeiffer, Loren N.; Baldwin, K. W.

    2004-12-01

    At a very low-temperature of 9 mK, electrons in the second Landau level of an extremely high-mobility two-dimensional electron system exhibit a very complex electronic behavior. With a varying filling factor, quantum liquids of different origins compete with several insulating phases leading to an irregular pattern in the transport parameters. We observe a fully developed v = 2+2/5 state separated from the even-denominator v = 2+1/2 state by an insulating phase and a v = 2+2/7 and v = 2+1/5 state surrounded by such phases. A developing plateau at v = 2+3/8 points to the existence of other even-denominator states.

  20. Application of quasi-degenerate perturbation theory to the calculation of rotational energy levels of methane vibrational polyads.

    PubMed

    Cassam-Chenaï, P; Rousseau, G; Ilmane, A; Bouret, Y; Rey, M

    2015-07-21

    In previous works, we have introduced an alternative perturbation scheme to find approximate solutions of the spectral problem for the rotation-vibration molecular Hamiltonian. An important feature of our approach is that the zero order Hamiltonian is the direct product of a purely vibrational Hamiltonian with the identity on the rotational degrees of freedom. The convergence of our method for the methane vibrational ground state was very satisfactory and our predictions were quantitative. In the present article, we provide further details on the implementation of the method in the degenerate and quasi-degenerate cases. The quasi-degenerate version of the method is tested on excited polyads of methane, and the results are assessed with respect to a variational treatment. The optimal choice of the size of quasi-degenerate spaces is determined by a trade-off between speed of convergence of the perturbation series and the computational effort to obtain the effective super-Hamiltonian. PMID:26203014

  1. Application of quasi-degenerate perturbation theory to the calculation of rotational energy levels of methane vibrational polyads

    SciTech Connect

    Cassam-Chenaï, P. Rousseau, G.; Ilmane, A.; Bouret, Y.; Rey, M.

    2015-07-21

    In previous works, we have introduced an alternative perturbation scheme to find approximate solutions of the spectral problem for the rotation-vibration molecular Hamiltonian. An important feature of our approach is that the zero order Hamiltonian is the direct product of a purely vibrational Hamiltonian with the identity on the rotational degrees of freedom. The convergence of our method for the methane vibrational ground state was very satisfactory and our predictions were quantitative. In the present article, we provide further details on the implementation of the method in the degenerate and quasi-degenerate cases. The quasi-degenerate version of the method is tested on excited polyads of methane, and the results are assessed with respect to a variational treatment. The optimal choice of the size of quasi-degenerate spaces is determined by a trade-off between speed of convergence of the perturbation series and the computational effort to obtain the effective super-Hamiltonian.

  2. Expression levels of IL-17 and TNF-α in degenerated lumbar intervertebral discs and their correlation

    PubMed Central

    LIU, XIAO-GANG; HOU, HONG-WEI; LIU, YI-LIN

    2016-01-01

    The present study aimed to investigate the expression and roles of interleukin (IL)-17 and tumor necrosis factor (TNF)-α in intervertebral disc degeneration (IDD) and to identify the association between the effects of IL-17 and TNF-α in IDD. This may increase understanding of the pathogenic mechanism underlying IDD, and aid the development of alternative therapies. The experimental group consisted of 40 samples of nucleus pulposus tissue obtained from the intervertebral discs (IVDs) of patients with IDD by surgical intervention, and was further divided into an annulus fibrosus disrupted group, comprising 18 patients in which the external annulus was ruptured, and an annulus fibrosus intact group comprising 22 patients. The control group consisted of 20 samples of nucleus pulposus tissue from the IVDs of patients with traumatic lumbar disc fractures. The mRNA and protein expression levels of IL-17 and TNF-α in the 50 tissue samples were detected by semi-quantitative reverse transcription polymerase chain reaction and immunohistochemical staining, respectively, and the results were statistically analyzed. The IL-17 and TNF-α protein and mRNA expression levels in the annulus fibrosus disrupted and annulus fibrosus intact groups were both higher compared with those in the control group. In addition, the expression levels of IL-17 and TNF-α in the annulus fibrosus disrupted group were significantly higher compared with those in the annulus fibrosus intact group (P<0.01). A positive correlation was identified between the mRNA and protein expression levels of IL-17 and TNF-α in the experimental group (r=0.957, P<0.01). IL-17 and TNF-α may therefore be involved in the progression of human IDD, and may have synergistic effects in the development of IDD. PMID:27284317

  3. Loosely coupled level sets for retinal layers and drusen segmentation in subjects with dry age-related macular degeneration

    NASA Astrophysics Data System (ADS)

    Novosel, Jelena; Wang, Ziyuan; de Jong, Henk; Vermeer, Koenraad A.; van Vliet, Lucas J.

    2016-03-01

    Optical coherence tomography (OCT) is used to produce high-resolution three-dimensional images of the retina, which permit the investigation of retinal irregularities. In dry age-related macular degeneration (AMD), a chronic eye disease that causes central vision loss, disruptions such as drusen and changes in retinal layer thicknesses occur which could be used as biomarkers for disease monitoring and diagnosis. Due to the topology disrupting pathology, existing segmentation methods often fail. Here, we present a solution for the segmentation of retinal layers in dry AMD subjects by extending our previously presented loosely coupled level sets framework which operates on attenuation coefficients. In eyes affected by AMD, Bruch's membrane becomes visible only below the drusen and our segmentation framework is adapted to delineate such a partially discernible interface. Furthermore, the initialization stage, which tentatively segments five interfaces, is modified to accommodate the appearance of drusen. This stage is based on Dijkstra's algorithm and combines prior knowledge on the shape of the interface, gradient and attenuation coefficient in the newly proposed cost function. This prior knowledge is incorporated by varying the weights for horizontal, diagonal and vertical edges. Finally, quantitative evaluation of the accuracy shows a good agreement between manual and automated segmentation.

  4. Approximate altitude of water levels in wells completed in the Chicot and Evangeline aquifers in Fort Bend County and adjacent areas, Texas,January-February 1991

    USGS Publications Warehouse

    Locke, Glenn L.

    1993-01-01

    This report was prepared in cooperation with the Fort Bend Subsidence District, and presents maps of the approximate altitude of water levels in wells completed in the Chicot and Evangeline aquifers (figs. -2) during January-February 1991 in Fort Bend County and adjacent areas, Texas.  These approximate altitudes of water levels give an approximate depth to potable ground water within Fort Bend County and can be used to estimate depth for installing well pumps.

  5. Macular Degeneration

    MedlinePlus

    ... common early symptom. Dry AMD happens when the light-sensitive cells in the macula slowly break down. Your gradually lose your central vision. A common early symptom is that straight lines appear crooked. Regular comprehensive eye exams can detect macular degeneration before the disease ...

  6. Adjacent Segment Pathology after Anterior Cervical Fusion.

    PubMed

    Chung, Jae Yoon; Park, Jong-Beom; Seo, Hyoung-Yeon; Kim, Sung Kyu

    2016-06-01

    Anterior cervical fusion has become a standard of care for numerous pathologic conditions of the cervical spine. However, subsequent development of clinically significant disc disease at levels adjacent to fused discs is a serious long-term complication of this procedure. As more patients live longer after surgery, it is foreseeable that adjacent segment pathology (ASP) will develop in increasing numbers of patients. Also, ASP has been studied more intensively with the recent popularity of motion preservation technologies like total disc arthroplasty. The true nature and scope of ASP remains poorly understood. The etiology of ASP is most likely multifactorial. Various factors including altered biomechanical stresses, surgical disruption of soft tissue and the natural history of cervical disc disease contribute to the development of ASP. General factors associated with disc degeneration including gender, age, smoking and sports may play a role in the development of ASP. Postoperative sagittal alignment and type of surgery are also considered potential causes of ASP. Therefore, a spine surgeon must be particularly careful to avoid unnecessary disruption of the musculoligamentous structures, reduced risk of direct injury to the disc during dissection and maintain a safe margin between the plate edge and adjacent vertebrae during anterior cervical fusion.

  7. Adjacent Segment Pathology after Anterior Cervical Fusion

    PubMed Central

    Chung, Jae Yoon; Park, Jong-Beom; Seo, Hyoung-Yeon

    2016-01-01

    Anterior cervical fusion has become a standard of care for numerous pathologic conditions of the cervical spine. However, subsequent development of clinically significant disc disease at levels adjacent to fused discs is a serious long-term complication of this procedure. As more patients live longer after surgery, it is foreseeable that adjacent segment pathology (ASP) will develop in increasing numbers of patients. Also, ASP has been studied more intensively with the recent popularity of motion preservation technologies like total disc arthroplasty. The true nature and scope of ASP remains poorly understood. The etiology of ASP is most likely multifactorial. Various factors including altered biomechanical stresses, surgical disruption of soft tissue and the natural history of cervical disc disease contribute to the development of ASP. General factors associated with disc degeneration including gender, age, smoking and sports may play a role in the development of ASP. Postoperative sagittal alignment and type of surgery are also considered potential causes of ASP. Therefore, a spine surgeon must be particularly careful to avoid unnecessary disruption of the musculoligamentous structures, reduced risk of direct injury to the disc during dissection and maintain a safe margin between the plate edge and adjacent vertebrae during anterior cervical fusion. PMID:27340541

  8. Analysis of Risk Alleles and Complement Activation Levels in Familial and Non-Familial Age-Related Macular Degeneration

    PubMed Central

    Saksens, Nicole T. M.; Lechanteur, Yara T. E.; Verbakel, Sanne K.; Groenewoud, Joannes M. M.; Daha, Mohamed R.; Schick, Tina; Fauser, Sascha; Boon, Camiel J. F.; Hoyng, Carel B.; den Hollander, Anneke I.

    2016-01-01

    Aims Age-related macular degeneration (AMD) is a multifactorial disease, in which complement-mediated inflammation plays a pivotal role. A positive family history is an important risk factor for developing AMD. Certain lifestyle factors are shown to be significantly associated with AMD in non-familial cases, but not in familial cases. This study aimed to investigate whether the contribution of common genetic variants and complement activation levels differs between familial and sporadic cases with AMD. Methods and Results 1216 AMD patients (281 familial and 935 sporadic) and 1043 controls (143 unaffected members with a family history of AMD and 900 unrelated controls without a family history of AMD) were included in this study. Ophthalmic examinations were performed, and lifestyle and family history were documented with a questionnaire. Nine single nucleotide polymorphisms (SNPs) known to be associated with AMD were genotyped, and serum concentrations of complement components C3 and C3d were measured. Associations were assessed in familial and sporadic individuals. The association with risk alleles of the age-related maculopathy susceptibility 2 (ARMS2) gene was significantly stronger in sporadic AMD patients compared to familial cases (p = 0.017 for all AMD stages and p = 0.003 for advanced AMD, respectively). ARMS2 risk alleles had the largest effect in sporadic cases but were not significantly associated with AMD in densely affected families. The C3d/C3 ratio was a significant risk factor for AMD in sporadic cases and may also be associated with familial cases. In patients with a densely affected family this effect was particularly strong with ORs of 5.37 and 4.99 for all AMD and advanced AMD respectively. Conclusion This study suggests that in familial AMD patients, the common genetic risk variant in ARMS2 is less important compared to sporadic AMD. In contrast, factors leading to increased complement activation appear to play a larger role in patients with a

  9. Cortical screw trajectory for instrumentation and fusion in the setting of osteopathic compression fracture allows for percutaneous kyphoplasty for adjacent level compression fractures.

    PubMed

    Pacione, Donato; Kim, Irene; Wilson, Taylor A; Frempong-Boadu, Anthony

    2015-05-01

    Spinal fixation in the osteoporotic patient can be challenging due to the poor trabecular bone quality of the vertebral body. Patients with osteoporotic vertebral body compression fractures are at risk for future compression fractures at adjacent levels, especially after cement augmentation. The purpose of this technical report is to describe the utilization of a cortical screw trajectory along with kyphoplasty for a patient with an osteoporotic compression fracture as well as degenerative spinal disease. This trajectory allows for the possibility of percutaneous pedicle access in the event of future compression fractures. Our patient underwent a decompressive laminectomy and kyphoplasty at the level of an osteoporotic compression fracture. The fracture was stabilized with cortical screw instrumentation and fusion at a level above and a level below the fracture. Subsequently the patient developed an adjacent level fracture within the fusion construct. Due to the utilization of a cortical screw trajectory for the initial fusion, the traditional pedicle trajectory was still accessible. As a result, the new fracture was treated with a percutaneous kyphoplasty through a standard pedicle trajectory. In conclusion, the use of a cortical screw trajectory for stabilization of osteoporotic compression fractures provides for a stronger bone screw interface and avoids osteoporotic trabecular vertebral body bone. At the same time this trajectory allows for future percutaneous pedicular access in the event that the patient suffers future compression fractures.

  10. Water-quality, water-level, and lake-bottom-sediment data collected from the defense fuel supply point and adjacent properties, Hanahan, South Carolina, 1990-96

    USGS Publications Warehouse

    Petkewich, M.D.; Vroblesky, D.A.; Robertson, J.F.; Bradley, P.M.

    1997-01-01

    A 9-year scientific investigation to determine the potential for biore-mediation of ground-water contamination and to monitor the effectiveness of an engineered bioremediation system located at the Defense Fuel Supply Point and adjacent properties in Hanahan, S.C., has culminated in the collection of abundant water-quality and water-level data.This report presents the analytical results of the study that monitored the changes in surface- and ground-water quality and water-table elevations in the study area from December 1990 to January 1996. This report also presents analytical results of lake-bottom sediments collected in the study area.

  11. Water-Level Data for the Albuquerque Basin and Adjacent Areas, Central New Mexico, Period of Record Through 2004

    USGS Publications Warehouse

    DeWees, R.K.

    2006-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25 to 40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompass the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the Albuquerque Basin are obtained solely from ground-water resources. An increase of approximately 20 percent in the population from 1991 to present also resulted in an increased demand for water. From April 1982 through September 1983, a network of wells was established to monitor changes in ground-water levels throughout the Albuquerque Basin. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly. Currently (2004), the network consists of 234 wells and piezometers. This report presents water-level data collected by U.S. Geological Survey personnel at 155 sites through 2004. Water-level and other data for 71 sites are collected by other agencies. Water-level data for 8 sites of the 155 sites measured by the U.S. Geological Survey were not available for this report.

  12. Macular degeneration (image)

    MedlinePlus

    Macular degeneration is a disease of the retina that affects the macula in the back of the eye. ... see fine details. There are two types of macular degeneration, dry and wet. Dry macular degeneration is more ...

  13. Power and polarization dependences of ultra-narrow electromagnetically induced absorption (EIA) spectra of 85 Rb atoms in degenerate two-level system

    NASA Astrophysics Data System (ADS)

    Qureshi, Muhammad Mohsin; Rehman, Hafeez Ur; Noh, Heung-Ryoul; Kim, Jin-Tae

    2016-05-01

    We have investigated ultra-narrow EIA spectral features with respect to variations of polarizations and powers of pump laser beam in a degenerate two-level system of the transition of 85 Rb D2 transition line. Polarizations of the probe laser beam in two separate experiments were fixed at right circular and horizontal linear polarizations, respectively while the polarizations of the pump lasers were varied from initial polarizations same as the probe laser beams to orthogonal to probe polarizations. One homemade laser combined with AOMs was used to the pump and probe laser beams instead of two different lasers to overcome broad linewidths of the homemade lasers. Theoretically, probe absorption coefficients have been calculated from optical Bloch equations of the degenerate two level system prepared by a pump laser beam. In the case of the circular polarization, EIA signal was obtained as expected theoretically although both pump and probe beams have same polarization. The EIA signal become smaller as power increases and polarizations of the pump and probe beams were same. When the polarization of the pump beam was linear polarization, maximum EIA signal was obtained theoretically and experimentally. Experimental EIA spectral shapes with respect to variations of the pump beam polarization shows similar trends as the theoretical results.

  14. Low-level laser therapy to recovery testicular degeneration in rams: effects on seminal characteristics, scrotal temperature, plasma testosterone concentration, and testes histopathology.

    PubMed

    Alves, Maíra Bianchi Rodrigues; de Arruda, Rubens Paes; Batissaco, Leonardo; Florez-Rodriguez, Shirley Andrea; de Oliveira, Bruna Marcele Martins; Torres, Mariana Andrade; Ravagnani, Gisele Mouro; Lançoni, Renata; de Almeida, Tamie Guibu; Storillo, Vanessa Martins; Vellone, Vinicius Silva; Franci, Celso Rodrigues; Thomé, Helder Esteves; Canella, Carolina Luz; De Andrade, André Furugen Cesar; Celeghini, Eneiva Carla Carvalho

    2016-05-01

    The aim of this study was to investigate the efficiency of low-level laser therapy (LLLT) to recovery testicular degeneration in rams. In the first study, rams were induced to testicular degeneration by scrotal insulation, and then, they were treated using LLLT at 28 J/cm(2) (INS28) or 56 J/cm(2) (INS56) energy densities. Sperm kinetics, morphology, and membranes integrity as well as proportion of lumen area in seminiferous tubule were assessed. In the second study, rams were submitted or not to scrotal insulation and treated or not by the best protocol of LLLT defined by experiment 1 (INS28). In this study were evaluated sperm kinetics, morphology, membranes integrity, ROS production, and DNA integrity. Testosterone serum concentration and proportion of lumen area in seminiferous tubule were also analyzed. Insulation was effective in promoting sperm injuries in both experiments. Biostimulatory effect was observed in experiment 1: INS28 presented smaller proportion of lumen area (P = 0.0001) and less degeneration degree (P = 0.0002). However, in experiment 2, there was no difference between the groups (P = 0.17). In addition, LLLT did not improve sperm quality, and there was a decreasing for total and progressive motility (P = 0.02) and integrity of sperm membranes (P = 0.01) in LLLT-treated groups. Moreover, testosterone concentration was not improved by LLLT (P = 0.37). Stimulation of aerobic phosphorylation by LLLT may have led to a deregulated increase in ROS leading to sperm damages. Thus, LLLT at energy of 28 J/cm(2) (808 nm of wavelength and 30 mW of power output) can induce sperm damages and increase the quantity of cells in seminiferous tubule in rams. PMID:26914685

  15. American Macular Degeneration Foundation

    MedlinePlus

    ... to content Contact DONATE Search for: Search Saving sight through research and education American Macular Degeneration Foundation Saving Sight Through Research and Education Menu About Macular Degeneration ...

  16. Water-level altitudes 1998 and water-level changes 1990-98 and 1997-98 in the Chicot and Evangeline aquifers, Fort Bend County and adjacent areas, Texas

    USGS Publications Warehouse

    Coplin, L.S.; Santos, H.X.

    1998-01-01

    This report is one in an annual series of reports that depicts water-level altitudes and water-level changes since 1990 in the Chicot and Evangeline aquifers in Fort Bend County and adjacent areas, Texas. The report, prepared in cooperation with the Ford Bend Subsidence District, presents maps for the Chicot and Evangeline aquifers showing the approximate water-level altitudes in wells in 1998 and approximate water-level changes in wells from 1990 to 1998 and from 1997 to 1998. The most recent previously published water-level-altitude maps and water-level-change maps for the two aquifers are by Coplin and others (1997). The earliest water-level-altitude maps and water-level-change maps for the Chicot aquifer are by Wesselman (1972). The first maps of water-level altitudes and water-level changes for the Chicot and Evangeline aquifers are by Locke (1990).

  17. [Hepatolenticular degeneration].

    PubMed

    Zudenigo, D; Relja, M

    1990-01-01

    Hepatolenticular degeneration (Wilson's disease) is a hereditary disease in which metabolic disorder of copper leads to its accumulation in the liver, brain, cornea and kidneys with consequent pathologic changes in those organs. Hereditary mechanism of the disease is autosomal recessive with prevalence of 30-100 per 1,000,000 inhabitants. Etiology of this disease is not yet explained. There are two hypotheses. The first one is that it is the disorder of ceruloplasmine metabolism caused by insufficient synthesis of normal ceruloplasmine, or synthesis of functionally abnormal ceruloplasmine. The second one is: the block of copper biliar excretion which is the consequence of the liver lysosomes functional defect. Pathogenetic mechanism of disease is firstly long-term accumulation of copper in the liver, and later, when the liver depo is full, its releasing in circulation and accumulation in the brain, cornea, kidneys and bones, which causes adequate pathologic changes. Toxic activity of copper is the consequence of its activity on enzymes, particularly on those with -SH group. There are two basic clinical forms of the disease: liver disease or neurologic disease. Before puberty the liver damage is more frequent, while in adolescents and young adults neurologic form of the disease is usual. The liver disease is nonspecific and characterized by symptoms of cirrhosis and chronic aggressive hepatitis. The only specificity is hemolytic anemia which, in combination with previous symptoms, is important for diagnosis of the disease. Neurologic symptoms are the most frequent consequence of pathologic changes in the basal ganglia. In our patients the most frequent symptoms were tremor (63%); dysarthria, choreoathetosis and rigor (38%); ataxia and mental disorders (31%); dysphagia and dystonia (12%), diplopia, hypersalivation, nystagmus and Babinski's sign (6%). Among pathologic changes in other tissues and organs the most important is the finding of Kayser-Fleischer ring in the

  18. The Incidence of Adjacent Segment Breakdown in Polysegmental Thoracolumbar Fusions of Three or More Levels with Minimum 5-Year Follow-up

    PubMed Central

    Abraham, Edward P.; Manson, Neil A.; McKeon, Melissa D.

    2014-01-01

    Study Design Retrospective cohort study. Objective To identify the incidence of adjacent segment pathology (ASP) after thoracolumbar fusion of three or more levels, the risk factors for the development of ASP, and the need for further surgical intervention in this particular patient population. Methods A retrospective analysis of a prospective surgical database identified 217 patients receiving polysegmental (≥ 3 levels) spinal fusion with minimum 5-year follow-up. Risk factors were evaluated, and the following data were obtained from the review of radiographs and charts: radiographic measures—levels fused, fusion status, presence of ASP; clinical measures—patient assessment, Oswestry Disability Index (ODI), and the need for further surgery. Results The incidence of radiographic ASP (RASP) was 29%; clinical or symptomatic ASP (CASP), 18%; and those requiring surgery, 9%. Correlation was observed between ODI and ASP, symptomatic ASP, and need for revision surgery. Age, preoperative degenerative diagnosis, and absence of fusion demonstrated significant association to ASP. Conclusions ASP was observed in a significant number of patients receiving polysegmental fusion of three or more levels. ODI scores correlated to RASP, CASP, and the need for revision surgery. PMID:25072002

  19. The Incidence of Adjacent Segment Breakdown in Polysegmental Thoracolumbar Fusions of Three or More Levels with Minimum 5-Year Follow-up.

    PubMed

    Abraham, Edward P; Manson, Neil A; McKeon, Melissa D

    2014-06-01

    Study Design Retrospective cohort study. Objective To identify the incidence of adjacent segment pathology (ASP) after thoracolumbar fusion of three or more levels, the risk factors for the development of ASP, and the need for further surgical intervention in this particular patient population. Methods A retrospective analysis of a prospective surgical database identified 217 patients receiving polysegmental (≥ 3 levels) spinal fusion with minimum 5-year follow-up. Risk factors were evaluated, and the following data were obtained from the review of radiographs and charts: radiographic measures-levels fused, fusion status, presence of ASP; clinical measures-patient assessment, Oswestry Disability Index (ODI), and the need for further surgery. Results The incidence of radiographic ASP (RASP) was 29%; clinical or symptomatic ASP (CASP), 18%; and those requiring surgery, 9%. Correlation was observed between ODI and ASP, symptomatic ASP, and need for revision surgery. Age, preoperative degenerative diagnosis, and absence of fusion demonstrated significant association to ASP. Conclusions ASP was observed in a significant number of patients receiving polysegmental fusion of three or more levels. ODI scores correlated to RASP, CASP, and the need for revision surgery.

  20. Mitochondrial DNA Variants Mediate Energy Production and Expression Levels for CFH, C3 and EFEMP1 Genes: Implications for Age-Related Macular Degeneration

    PubMed Central

    Kenney, M. Cristina; Chwa, Marilyn; Atilano, Shari R.; Pavlis, Janelle M.; Falatoonzadeh, Payam; Ramirez, Claudio; Malik, Deepika; Hsu, Tiffany; Woo, Grace; Soe, Kyaw; Nesburn, Anthony B.; Boyer, David S.; Kuppermann, Baruch D.; Jazwinski, S. Michal; Miceli, Michael V.; Wallace, Douglas C.; Udar, Nitin

    2013-01-01

    Background Mitochondrial dysfunction is associated with the development and progression of age-related macular degeneration (AMD). Recent studies using populations from the United States and Australia have demonstrated that AMD is associated with mitochondrial (mt) DNA haplogroups (as defined by combinations of mtDNA polymorphisms) that represent Northern European Caucasians. The aim of this study was to use the cytoplasmic hybrid (cybrid) model to investigate the molecular and biological functional consequences that occur when comparing the mtDNA H haplogroup (protective for AMD) versus J haplogroup (high risk for AMD). Methodology/Principal Findings Cybrids were created by introducing mitochondria from individuals with either H or J haplogroups into a human retinal epithelial cell line (ARPE-19) that was devoid of mitochondrial DNA (Rho0). In cybrid lines, all of the cells carry the same nuclear genes but vary in mtDNA content. The J cybrids had significantly lower levels of ATP and reactive oxygen/nitrogen species production, but increased lactate levels and rates of growth. Q-PCR analyses showed J cybrids had decreased expressions for CFH, C3, and EFEMP1 genes, high risk genes for AMD, and higher expression for MYO7A, a gene associated with retinal degeneration in Usher type IB syndrome. The H and J cybrids also have comparatively altered expression of nuclear genes involved in pathways for cell signaling, inflammation, and metabolism. Conclusion/Significance Our findings demonstrate that mtDNA haplogroup variants mediate not only energy production and cell growth, but also cell signaling for major molecular pathways. These data support the hypothesis that mtDNA variants play important roles in numerous cellular functions and disease processes, including AMD. PMID:23365660

  1. Hepatocerebral degeneration

    MedlinePlus

    ... Liver damage can lead to the buildup of ammonia and other toxic materials in the body. This ... Walking instability Laboratory tests may show a high ammonia level in the bloodstream and abnormal liver function. ...

  2. Macular Degeneration Partnership

    MedlinePlus

    AMD Macular Degeneration Partnership High Contrast Original + Font Size – Home About AMD Dry AMD Wet AMD Experience AMD Living with ... vision on a daily basis. AMD (Age Related Macular Degeneration) Partnership Listen AMD Month Public Service Announcement To ...

  3. Levels of iron, silver, zinc, and lead in oranges and avocados from two gold-rich towns compared with levels in an adjacent gold-deficient town

    SciTech Connect

    Golow, A.A.; Laryea, J.N. )

    1994-09-01

    Fruits such as oranges and avocados are important sources of drinks and food in the Ghanaian Society. If such fruits contain various types of metals they may augument the types and amounts of them in the human body. The metals in fruits may depend on what is in the soils from which they are grown. If the soils contain toxic metals like lead, mercury and cadmium then the consumers may be poisoned as happened in the [open quotes]Ouchi - ouchi[close quotes], disease in Japan and similar episodes. In the area under study, the Geological Survey indicates the presence of 2.5 ppm of lead, 10 - 20 ppm of copper and less than 15 ppm of nickel. Silver, not reported in commercial amounts, is a byproduct of gold productions at Obuasi. Since copper and nickel are presented in the area traces of silver will certainly occur. In the same manner zinc is usually associated with lead as sulphide of zinc blend trace amounts of it are likely to occur in the area. Of the four metals measured, iron and zinc essential for citrus. The extractable iron and zinc in the area of study were 90 and 1.8 mg/kg, levels on the low side for the healthy growth of crops. The investigation reported here is the comparison of the levels of some metals in oranges and avocados from farms in Obuasi and Konongo with those from farms in Kumasi City. This is a part of a project aimed at finding out differences in the metal contents of various food crops grown in various regions of the country. Konongo and Obuasi have soils which are rich in gold but Kumasi city, which is not too distant from these towns, does not have gold in its soil. 18 refs., 1 tab.

  4. Macular Degeneration: An Overview.

    ERIC Educational Resources Information Center

    Chalifoux, L. M.

    1991-01-01

    This article presents information on macular degeneration for professionals helping persons with this disease adjust to their visual loss. It covers types of macular degeneration, the etiology of the disease, and its treatment. Also considered are psychosocial problems and other difficulties that persons with age-related macular degeneration face.…

  5. Association Study of Mannose-Binding Lectin Levels and Genetic Variants in Lectin Pathway Proteins with Susceptibility to Age-Related Macular Degeneration: A Case-Control Study

    PubMed Central

    Osthoff, Michael; Dean, Melinda M.; Baird, Paul N.; Richardson, Andrea J.; Daniell, Mark; Guymer, Robyn H.; Eisen, Damon P.

    2015-01-01

    Background In age-related macular degeneration (AMD) the complement system is thought to be activated by chronic oxidative damage with genetic variants identified in the alternative pathway as susceptibility factors. However, the involvement of the lectin pathway of complement, a key mediator of oxidative damage, is controversial. This study investigated whether mannose-binding lectin (MBL) levels and genetic variants in lectin pathway proteins, are associated with the predisposition to and severity of AMD. Methods MBL levels and single nucleotide polymorphisms (SNPs) in the MBL2 and the ficolin-2 (FCN2) gene were determined in 109 patients with AMD and 109 age- and sex-matched controls. Results MBL expression levels were equally distributed in both cases (early and late AMD) and controls (p>0.05). However, there was a trend towards higher median MBL levels in cases with late AMD compared to cases with early AMD (1.0 vs. 0.4 μg/ml, p = 0.09) and MBL deficiency (<0.5 μg/ml) was encountered less frequently in the late AMD group (35% vs 56%, p = 0.03). FCN2 and MBL2 allele frequencies were similarly distributed in early and late AMD cases compared with controls (p>0.05 for all analyses) as were MBL2 genotypes. Similarly, there was no significant difference in allele frequencies in any SNPs in either the MBL2 or FCN2 gene in cases with early vs. late AMD. Conclusions SNPs of lectin pathway proteins investigated in this study were not associated with AMD or AMD severity. However, MBL levels deserve further study in a larger cohort of early vs. late AMD patients to elucidate any real effect on AMD severity. PMID:26207622

  6. Environmental data package for ORNL Solid Waste Storage Area Four, the adjacent intermediate-level liquid waste transfer line, and the liquid waste pilot pit area

    SciTech Connect

    Davis, E.C.; Shoun, R.R.

    1986-09-01

    The Oak Ridge National Laboratory Remedial Action Program has determined through its review of past environmental studies that Solid Waste Storage Area Four (SWSA-4) continually releases radioactivity to White Oak Creek and therefore requires application of the site stabilization and remedial actions outlined under the 3004u provisions of the Resource Conservation and Recovery Act. Under these provisions, a Remedial Investigation/Feasibility Study (RI/FS) forms the basis for determining the extent of actions. This report assembles available historical and environmental data relative to the SWSA-4 waste area grouping (WAG), which includes the 9.3-ha SWSA-4 site, the adjacent abandoned intermediate-level liquid waste transfer line, and the experimental pilot pit area. The rationale for grouping these three waste management units into the SWSA-4 WAG is the fact that they each lie in the same hydrologic unit and share a common tributary to White Oak Creek. The results of this compilation demonstrate that although a considerable number of studies have been carried out in SWSA-4, needs such as installation of water quality wells and continued monitoring and reporting of hydrologic data still exist. These needs will become even more critical as the RI/FS process proceeds and remedial measures for the site are considered. Fewer studies have been carried out to characterize the extent of contamination at the waste transfer line and the pilot pit area. Alternatives for characterizing and stabilizing these two minor components of the SWSA-4 WAG are presented; however, extensive remedial actions do not appear to be warranted.

  7. Effects of closure of an urban level I trauma centre on adjacent hospitals and local injury mortality: a retrospective, observational study

    PubMed Central

    Crandall, Marie; Sharp, Douglas; Wei, Xiong; Nathens, Avery; Hsia, Renee Y

    2016-01-01

    Objective To determine the association of the Martin Luther King Jr Hospital (MLK) closure on the distribution of admissions on adjacent trauma centres, and injury mortality rates in these centres and within the county. Design Observational, retrospective study. Setting Non-public patient-level data from the state of California were obtained for all trauma patients from 1999 to 2009. Geospatial analysis was used to visualise the redistribution of trauma patients to other hospitals after MLK closed. Variance of observed to expected injury mortality using multivariate logistic regression was estimated for the study period. Participants A total of 37 131 trauma patients were admitted to the five major south Los Angeles trauma centres from the MLK service area between 1999 and 2009. Main outcome measures (1) Number and type of trauma admissions to trauma centres in closest proximity to MLK; (2) inhospital injury mortality of trauma patients after the trauma centre closure. Results During and after the MLK closure, trauma admissions increased at three of the four nearby hospitals, particularly admissions for gunshot wounds (GSWs). This redistribution of patient load was accompanied by a dramatic change in the payer mix for surrounding hospitals; one hospital's share of uninsured more than tripled from 12.9% in 1999 to 44.6% by 2009. Overall trauma mortality did not significantly change, but GSW mortality steadily and significantly increased after the closure from 5.0% in 2007 to 7.5% in 2009. Conclusions Though local hospitals experienced a dramatic increase in trauma patient volume, overall mortality for trauma patients did not significantly change after MLK closed. PMID:27165650

  8. Rare genetic variants in the CFI gene are associated with advanced age-related macular degeneration and commonly result in reduced serum factor I levels

    PubMed Central

    Kavanagh, David; Yu, Yi; Schramm, Elizabeth C.; Triebwasser, Michael; Wagner, Erin K.; Raychaudhuri, Soumya; Daly, Mark J.; Atkinson, John P.; Seddon, Johanna M.

    2015-01-01

    To assess a potential diagnostic and therapeutic biomarker for age-related macular degeneration (AMD), we sequenced the complement factor I gene (CFI) in 2266 individuals with AMD and 1400 without, identifying 231 individuals with rare genetic variants. We evaluated the functional impact by measuring circulating serum factor I (FI) protein levels in individuals with and without rare CFI variants. The burden of very rare (frequency <1/1000) variants in CFI was strongly associated with disease (P = 1.1 × 10−8). In addition, we examined eight coding variants with counts ≥5 and saw evidence for association with AMD in three variants. Individuals with advanced AMD carrying a rare CFI variant had lower mean FI compared with non-AMD subjects carrying a variant (P < 0.001). Further new evidence that FI levels drive AMD risk comes from analyses showing individuals with a CFI rare variant and low FI were more likely to have advanced AMD (P = 5.6 × 10−5). Controlling for covariates, low FI increased the risk of advanced AMD among those with a variant compared with individuals without advanced AMD with a rare CFI variant (OR 13.6, P = 1.6 × 10−4), and also compared with control individuals without a rare CFI variant (OR 19.0, P = 1.1 × 10−5). Thus, low FI levels are strongly associated with rare CFI variants and AMD. Enhancing FI activity may be therapeutic and measuring FI provides a screening tool for identifying patients who are most likely to benefit from complement inhibitory therapy. PMID:25788521

  9. Testicular degeneration in Huntington disease.

    PubMed

    Van Raamsdonk, Jeremy M; Murphy, Zoe; Selva, David M; Hamidizadeh, Reza; Pearson, Jacqueline; Petersén, Asa; Björkqvist, Maria; Muir, Cameron; Mackenzie, Ian R; Hammond, Geoffrey L; Vogl, A Wayne; Hayden, Michael R; Leavitt, Blair R

    2007-06-01

    Huntington disease (HD) is an adult onset, neurodegenerative disorder that results from CAG expansion in the HD gene. Recent work has demonstrated testicular degeneration in mouse models of HD and alterations in the hypothalamic-pituitary-gonadal (HPG) axis in HD patients. Here, we show that HD patients have specific testicular pathology with reduced numbers of germ cells and abnormal seminiferous tubule morphology. In the YAC128 mouse model, testicular degeneration develops prior to 12 months of age, but at 12 months, there is no evidence for decreased testosterone levels or loss of GnRH neurons in the hypothalamus. This suggests that testicular pathology results from a direct toxic effect of mutant huntingtin in the testis and is supported by the fact that huntingtin is highly expressed in the affected cell populations in the testis. Understanding the pathogenesis of HD in the testis may reveal common critical pathways which lead to degeneration in both the brain and testis.

  10. A level-set method for pathology segmentation in fluorescein angiograms and en face retinal images of patients with age-related macular degeneration

    NASA Astrophysics Data System (ADS)

    Mohammad, Fatimah; Ansari, Rashid; Shahidi, Mahnaz

    2013-03-01

    The visibility and continuity of the inner segment outer segment (ISOS) junction layer of the photoreceptors on spectral domain optical coherence tomography images is known to be related to visual acuity in patients with age-related macular degeneration (AMD). Automatic detection and segmentation of lesions and pathologies in retinal images is crucial for the screening, diagnosis, and follow-up of patients with retinal diseases. One of the challenges of using the classical level-set algorithms for segmentation involves the placement of the initial contour. Manually defining the contour or randomly placing it in the image may lead to segmentation of erroneous structures. It is important to be able to automatically define the contour by using information provided by image features. We explored a level-set method which is based on the classical Chan-Vese model and which utilizes image feature information for automatic contour placement for the segmentation of pathologies in fluorescein angiograms and en face retinal images of the ISOS layer. This was accomplished by exploiting a priori knowledge of the shape and intensity distribution allowing the use of projection profiles to detect the presence of pathologies that are characterized by intensity differences with surrounding areas in retinal images. We first tested our method by applying it to fluorescein angiograms. We then applied our method to en face retinal images of patients with AMD. The experimental results included demonstrate that the proposed method provided a quick and improved outcome as compared to the classical Chan-Vese method in which the initial contour is randomly placed, thus indicating the potential to provide a more accurate and detailed view of changes in pathologies due to disease progression and treatment.

  11. Risk Factors Associated with Adjacent and Remote- Level Pathologic Vertebral Compression Fracture Following Balloon Kyphoplasty: 2-Year Follow-Up Comparison Versus Conservative Treatment.

    PubMed

    Faloon, Michael J; Ruoff, Mark; Deshpande, Chetan; Hohman, Donald; Dunn, Conor; Beckloff, Nicholas; Patel, Dipak V

    2015-01-01

    Vertebral compression fractures are a significant source of morbidity and mortality among patients of all age groups. These fractures result in both acute and chronic pain. Patients who sustain such fractures are known to suffer from more comorbidities and have a higher mortality rate compared with healthy people in the same age group. In recent years, balloon kyphoplasty has become a popular method for treating vertebral compression fractures. However, as longer-term follow-up becomes available, the effects of cement augmentation on adjacent spinal segments require investigation. Here, we have performed a retrospective chart review of 258 consecutive patients with pathologic vertebral compression fractures secondary to osteoporosis, treated by either conservative measures or balloon kyphoplasty with polymethylmethacrylate cement augmentation. Multivariate analysis of patient comorbidities was performed to assess the risks associated with subsequent adjacent and remote compression fracture at a minimum of 2 years follow-up. A total of 258 patients had 361 vertebral compression fractures. A total of 121 patients were treated nonoperatively and 137 underwent balloon kyphoplasty with polymethylmethacrylate cement augmentation. The mean follow-up for both cohorts was 2.7 years (range, 2-6 years). The kyphoplasty cohort was significantly older than the nonoperative cohort (mean age, 78.5 versus 74.2 years; p = 0.02), had 24 more patients with diabetes mellitus (37 versus 13; p = 0.05), and had 34 more patients with a history of smoking (50 versus 16; p = 0.05). However, the kyphoplasty cohort had less patients with a history of non-steroidal anti-inflammatory drug (NSAID) use (45 versus 71; p = 0.07). There were no demographic differences between groups in patients with secondary fractures. Nonoperative treatment was identified as a statistically significant independent risk factor for subsequent vertebral compression fracture [odds ratio (OR), 2.28]. Univariate

  12. Double Degenerate Binary Systems

    SciTech Connect

    Yakut, K.

    2011-09-21

    In this study, angular momentum loss via gravitational radiation in double degenerate binary (DDB)systems (NS + NS, NS + WD, WD + WD, and AM CVn) is studied. Energy loss by gravitational waves has been estimated for each type of systems.

  13. PHYSICAL BASIS OF QUANTUM ELECTRONICS: Inversion-free amplification of a probe field in a medium consisting of two-level degenerate atoms in the presence of a magnetic field

    NASA Astrophysics Data System (ADS)

    Konopleva, N. P.; Tumaikin, Anatolii M.

    1999-08-01

    The propagation of a probe field in a medium consisting of two-level atoms, degenerate in relation to the Jg = 1/2 → Je = 1/2 transition, is examined. The atoms are pumped by a circularly polarised resonant field in the presence of a static magnetic field. It is shown that under these conditions one of the normal waves may be amplified in the absence of inversion in the medium. In strong optical and magnetic fields, inversion-free amplification is possible for a pump with a finite spectral width, which may be much greater than the natural width of the excited level.

  14. Molecular mechanisms in the initiation phase of Wallerian degeneration.

    PubMed

    Chang, Biao; Quan, Qi; Lu, Shibi; Wang, Yu; Peng, Jiang

    2016-08-01

    Axonal degeneration is an early hallmark of nerve injury and many neurodegenerative diseases. The discovery of the Wallerian degeneration slow mutant mouse, in which axonal degeneration is delayed, revealed that Wallerian degeneration is an active progress and thereby illuminated the mechanisms underlying axonal degeneration. Nicotinamide mononucleotide adenylyltransferase 2 and sterile alpha and armadillo motif-containing protein 1 play essential roles in the maintenance of axon integrity by regulating the level of nicotinamide adenine dinucleotide, which seems to be the key molecule involved in the maintenance of axonal health. However, the function of nicotinamide mononucleotide remains debatable, and we discuss two apparently conflicting roles of nicotinamide mononucleotide in Wallerian degeneration. In this article, we focus on the roles of these molecules in the initiation phase of Wallerian degeneration to improve our understanding of the mechanisms underpinning this phenomenon. PMID:27062141

  15. Degenerate density perturbation theory

    NASA Astrophysics Data System (ADS)

    Palenik, Mark C.; Dunlap, Brett I.

    2016-09-01

    Fractional occupation numbers can be used in density functional theory to create a symmetric Kohn-Sham potential, resulting in orbitals with degenerate eigenvalues. We develop the corresponding perturbation theory and apply it to a system of Nd degenerate electrons in a harmonic oscillator potential. The order-by-order expansions of both the fractional occupation numbers and unitary transformations within the degenerate subspace are determined by the requirement that a differentiable map exists connecting the initial and perturbed states. Using the X α exchange-correlation (XC) functional, we find an analytic solution for the first-order density and first- through third-order energies as a function of α , with and without a self-interaction correction. The fact that the XC Hessian is not positive definite plays an important role in the behavior of the occupation numbers.

  16. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2014

    USGS Publications Warehouse

    Beman, Joseph E.

    2015-10-21

    An initial network of wells was established by the U.S. Geological Survey (USGS) in cooperation with the City of Albuquerque from April 1982 through September 1983 to monitor changes in groundwater levels throughout the basin. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. The network currently (2014) consists of 125 wells and piezometers. (A piezometer is a specialized well open to a specific depth in the aquifer, often of small diameter and nested with other piezometers open to different depths.) The USGS, in cooperation with the Albuquerque Bernalillo County Water Utility Authority, currently (2014) measures and reports water levels from the 125 wells and piezometers in the network; this report presents water-level data collected by USGS personnel at those 125 sites through water year 2014 (October 1, 2013, to September 30, 2014).

  17. Approximate water-level changes in wells completed in the Chicot and Evangeline aquifers, 1991-92, Fort Bend County and adjacent areas, Texas

    USGS Publications Warehouse

    Locke, Glenn L.; Santos, Horatio X.

    1992-01-01

    This report was prepared in cooperation with the Fort Bend Subsidence District, and presents data on water-level changes during 1991-92 in the Chicot and Evangeline aquifer (fig. 1-2) in Fort Bend County.  Water-level change maps were prepared previously by Locke (1990),and Locke and Barbie (1991), for both aquifers, and by Wesselman (1972) for the Chicot aquifer.

  18. Water-Level Data for the Albuquerque Basin and Adjacent Areas, Central New Mexico, Period of Record Through September 30, 2006

    USGS Publications Warehouse

    Beman, Joseph E.

    2007-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25 to 40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompass the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin are currently (2007) obtained solely from ground-water resources. An increase of about 20 percent in the population from 1990 to 2000 also resulted in an increased demand for water. From April 1982 through September 1983, a network of wells was established to monitor changes in ground-water levels throughout the basin. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly. Currently (2007), the network consists of 133 wells and piezometers. This report presents water-level data collected by U.S. Geological Survey personnel at 133 sites through 2007.

  19. Geologic and hydrologic data collected during 1976-1983 at the Sheffield low-level radioactive waste disposal site and adjacent areas, Sheffield, Illinois

    USGS Publications Warehouse

    Foster, J.B.; Garklavs, George; Mackey, G.W.

    1984-01-01

    Hydrogeologic studies were conducted at the low-level radioactive-waste disposal site near Sheffield, Illinois, from 1976-84. Data in this report include water levels in wells, lake stages, inorganic, organic, and radiometric chemical analyses of ground and surface water, hydraulic conductivities of glacial materials, grain-size distribution, clay and carbonate mineralogy, and cation exchange capacities of the glacial materials. Also included are results of petrographic analyses, physical measurements of wells, stratigraphy and lithology of cores collected from test wells, and horizontal coordinates of wells.

  20. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2012

    USGS Publications Warehouse

    Beman, Joseph E.

    2013-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25-40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when surface water from the Rio Grande began being treated and integrated into the system. A population increase of about 20 percent in the basin from 1990 to 2000 and a 22 percent increase from 2000 to 2010 resulted in an increased demand for water. An initial network of wells was established by the U.S. Geological Survey (USGS) in cooperation with the City of Albuquerque from April 1982 through September 1983 to monitor changes in groundwater levels throughout the basin. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. Currently (2012), the network consists of 126 wells and piezometers. (A piezometer is a specialized well open to a specific depth in the aquifer, often of small diameter and nested with other piezometers open to different depths.) The USGS, in cooperation with the Albuquerque Bernalillo County Water Utility Authority (ABCWUA), currently (2012) measures and reports water levels from the 126 wells and piezometers in the network; this report presents water-level data collected by USGS personnel at those 126 sites through water year 2012.

  1. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2013

    USGS Publications Warehouse

    Beman, Joseph E.

    2014-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25–40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when treatment and distribution of surface water from the Rio Grande began. A population increase of about 20 percent in the basin from 1990 to 2000 and a 22-percent increase from 2000 to 2010 resulted in an increased demand for water. An initial network of wells was established by the U.S. Geological Survey (USGS) in cooperation with the City of Albuquerque from April 1982 through September 1983 to monitor changes in groundwater levels throughout the basin. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. Currently (2013), the network consists of 123 wells and piezometers. (A piezometer is a specialized well open to a specific depth in the aquifer, often of small diameter and nested with other piezometers open to different depths.) The USGS, in cooperation with the Albuquerque Bernalillo County Water Utility Authority, currently (2013) measures and reports water levels from the 123 wells and piezometers in the network; this report presents water-level data collected by USGS personnel at those 123 sites through water year 2013.

  2. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2015

    USGS Publications Warehouse

    Beman, Joseph E.; Bryant, Christina F.

    2016-10-27

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25–40 miles wide. The basin is hydrologically defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift between San Acacia to the south and Cochiti Lake to the north. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when the Albuquerque Bernalillo County Water Utility Authority (ABCWUA) began treatment and distribution of surface water from the Rio Grande through the San Juan-Chama Drinking Water Project. A 20-percent population increase in the basin from 1990 to 2000 and a 22-percent population increase from 2000 to 2010 may have resulted in an increased demand for water in areas within the basin.An initial network of wells was established by the U.S. Geological Survey (USGS) in cooperation with the City of Albuquerque from April 1982 through September 1983 to monitor changes in groundwater levels throughout the Albuquerque Basin. In 1983, this network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly. The network currently (2015) consists of 124 wells and piezometers. (A piezometer is a specialized well open to a specific depth in the aquifer, often of small diameter and nested with other piezometers open to different depths.) The USGS, in cooperation with the ABCWUA, currently (2015) measures and reports water levels from the 124 wells and piezometers in the network; this report presents water-level data collected by USGS personnel at those 124 sites through water year 2015 (October 1, 2014, through September 30, 2015).

  3. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2009

    USGS Publications Warehouse

    Beman, Joseph E.; Torres, Leeanna T.

    2010-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25 to 40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompass the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when surface water from the Rio Grande began being treated and integrated into the system. An increase of about 20 percent in the population from 1990 to 2000 also resulted in an increased demand for water. A network of wells was established to monitor changes in groundwater levels throughout the basin from April 1982 through September 1983. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. Currently (2009), the network consists of 131 wells and piezometers. This report presents water-level data collected by U.S. Geological Survey personnel at 123 sites through water year 2009. In addition, data from four wells (Sites 140, 147, 148, and 149) owned, maintained, and measured by Sandia National Laboratories and three from Kirtland Air Force Base (Sites 119, 125, and 126) are presented in this report.

  4. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2011

    USGS Publications Warehouse

    Beman, Joseph E.

    2012-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25–40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when surface water from the Rio Grande began being treated and integrated into the system. An increase of about 20 percent in the basin human population from 1990 to 2000 and of about 22 percent increase from 2000 to 2010 also resulted in an increased demand for water. A network of wells was established by the U.S. Geological Survey in cooperation with the City of Albuquerque from April 1982 through September 1983 to monitor changes in groundwater levels throughout the basin. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. Currently (2011), the network consists of 126 wells and piezometers (a piezometer is a specialized well open to a specific depth in the aquifer and is often of small diameter and nested with other piezometers open to different depths). This report presents water-level data collected by U.S. Geological Survey personnel at those 126 sites through water year 2011 to better help the Albuquerque Bernalillo County Water Utility Authority manage water use.

  5. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2010

    USGS Publications Warehouse

    Beman, Joseph E.

    2011-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25-40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when surface water from the Rio Grande began being treated and integrated into the system. An increase of about 20 percent in the basin human population from 1990 to 2000 and about a 22 percent increase from 2000 to 2010 also resulted in an increased demand for water. A network of wells was established by the U.S. Geological Survey in cooperation with the City of Albuquerque to monitor changes in groundwater levels throughout the basin from April 1982 through September 1983. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. Currently (2010), the network consists of 124 wells and piezometers (a piezometer is a small-diameter subwell usually nested within a larger well). To better help the Albuquerque Bernalillo County Water Utility Authority manage water use, this report presents water-level data collected by U.S. Geological Survey personnel at those 124 sites through water year 2010.

  6. Water-Level Data for the Albuquerque Basin and Adjacent Areas, Central New Mexico, Period of Record Through September 30, 2007

    USGS Publications Warehouse

    Beman, Joseph E.

    2008-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25 to 40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompass the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin are currently (2007) obtained solely from ground-water resources. An increase of about 20 percent in the population from 1990 to 2000 also resulted in an increased demand for water. A network of wells was established to monitor changes in ground-water levels throughout the basin from April 1982 through September 1983. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. Currently (2007), the network consists of 131 wells and piezometers. This report presents water-level data collected by U.S. Geological Survey personnel at 131 sites through water-year 2007. Data from five sites (Sites 9, 10, 31, 71 and 78) were not measured during the 2007 water-year, but are included in this report because recent data are useful for comparison and (or) data have been collected that will be included in the water-year 2008 report.

  7. Water-Level Data for the Albuquerque Basin and Adjacent Areas, Central New Mexico, Period of Record Through September 30, 2008

    USGS Publications Warehouse

    Beman, Joseph E.

    2009-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25 to 40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompass the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin are currently (2008) obtained soley from ground-water resources. An increase of about 20 percent in the population from 1990 to 2000 also resulted in an increased demand for water. A network of wells was established to monitor changes in ground-water levels throughout the basin from April 1982 through September 1983. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. Currently (2008), the network consists of 144 wells and piezometers. This report presents water-level data collected by U.S. Geological Survey personnel at 125 sites through water-year 2008. In addition, data from 19 wells (Sites 127-30, 132-134, 136, 138-142 and 144-149) owned, maintained, and measured by Sandia National Laboratories are presented in this report.

  8. X-82 to Treat Age-related Macular Degeneration

    ClinicalTrials.gov

    2016-08-16

    Age-Related Macular Degeneration (AMD); Macular Degeneration; Exudative Age-related Macular Degeneration; AMD; Macular Degeneration, Age-related, 10; Eye Diseases; Retinal Degeneration; Retinal Diseases

  9. Temperature variations at nano-scale level in phase transformed nanocrystalline NiTi shape memory alloys adjacent to graphene layers.

    PubMed

    Amini, Abbas; Cheng, Chun; Naebe, Minoo; Church, Jeffrey S; Hameed, Nishar; Asgari, Alireza; Will, Frank

    2013-07-21

    The detection and control of the temperature variation at the nano-scale level of thermo-mechanical materials during a compression process have been challenging issues. In this paper, an empirical method is proposed to predict the temperature at the nano-scale level during the solid-state phase transition phenomenon in NiTi shape memory alloys. Isothermal data was used as a reference to determine the temperature change at different loading rates. The temperature of the phase transformed zone underneath the tip increased by ∼3 to 40 °C as the loading rate increased. The temperature approached a constant with further increase in indentation depth. A few layers of graphene were used to enhance the cooling process at different loading rates. Due to the presence of graphene layers the temperature beneath the tip decreased by a further ∼3 to 10 °C depending on the loading rate. Compared with highly polished NiTi, deeper indentation depths were also observed during the solid-state phase transition, especially at the rate dependent zones. Larger superelastic deformations confirmed that the latent heat transfer through the deposited graphene layers allowed a larger phase transition volume and, therefore, more stress relaxation and penetration depth. PMID:23744099

  10. Temperature variations at nano-scale level in phase transformed nanocrystalline NiTi shape memory alloys adjacent to graphene layers

    NASA Astrophysics Data System (ADS)

    Amini, Abbas; Cheng, Chun; Naebe, Minoo; Church, Jeffrey S.; Hameed, Nishar; Asgari, Alireza; Will, Frank

    2013-06-01

    The detection and control of the temperature variation at the nano-scale level of thermo-mechanical materials during a compression process have been challenging issues. In this paper, an empirical method is proposed to predict the temperature at the nano-scale level during the solid-state phase transition phenomenon in NiTi shape memory alloys. Isothermal data was used as a reference to determine the temperature change at different loading rates. The temperature of the phase transformed zone underneath the tip increased by ~3 to 40 °C as the loading rate increased. The temperature approached a constant with further increase in indentation depth. A few layers of graphene were used to enhance the cooling process at different loading rates. Due to the presence of graphene layers the temperature beneath the tip decreased by a further ~3 to 10 °C depending on the loading rate. Compared with highly polished NiTi, deeper indentation depths were also observed during the solid-state phase transition, especially at the rate dependent zones. Larger superelastic deformations confirmed that the latent heat transfer through the deposited graphene layers allowed a larger phase transition volume and, therefore, more stress relaxation and penetration depth.

  11. Temperature variations at nano-scale level in phase transformed nanocrystalline NiTi shape memory alloys adjacent to graphene layers.

    PubMed

    Amini, Abbas; Cheng, Chun; Naebe, Minoo; Church, Jeffrey S; Hameed, Nishar; Asgari, Alireza; Will, Frank

    2013-07-21

    The detection and control of the temperature variation at the nano-scale level of thermo-mechanical materials during a compression process have been challenging issues. In this paper, an empirical method is proposed to predict the temperature at the nano-scale level during the solid-state phase transition phenomenon in NiTi shape memory alloys. Isothermal data was used as a reference to determine the temperature change at different loading rates. The temperature of the phase transformed zone underneath the tip increased by ∼3 to 40 °C as the loading rate increased. The temperature approached a constant with further increase in indentation depth. A few layers of graphene were used to enhance the cooling process at different loading rates. Due to the presence of graphene layers the temperature beneath the tip decreased by a further ∼3 to 10 °C depending on the loading rate. Compared with highly polished NiTi, deeper indentation depths were also observed during the solid-state phase transition, especially at the rate dependent zones. Larger superelastic deformations confirmed that the latent heat transfer through the deposited graphene layers allowed a larger phase transition volume and, therefore, more stress relaxation and penetration depth.

  12. Highest brain bismuth levels and neuropathology are adjacent to fenestrated blood vessels in mouse brain after intraperitoneal dosing of bismuth subnitrate.

    PubMed

    Ross, J F; Broadwell, R D; Poston, M R; Lawhorn, G T

    1994-02-01

    A small fraction of humans ingesting bismuth (Bi)-containing medications develops neurotoxicity in which neuropsychiatric signs precede motor dysfunction. Large ip doses of Bi subnitrate (BSN) produce similar signs in mice, but little is known about the pathogenesis of neurotoxicity in either species. Adult female Swiss-Webster mice received a neurotoxic dose (2500 mg/kg ip) of BSN. Bi distribution and neuropathology were determined as follows: (1) Regions of central and peripheral nervous system were assayed for Bi by atomic absorption spectrometry (AAS) 28 days after dosing, (2) regional brain Bi distribution was demonstrated in histologic sections by autometallography 28 days after dosing, and (3) blood/brain barrier status and neuropathologic effects were evaluated by light and electron microscopic techniques 1, 3, and 7 days and 2, 3, 4, and 5 weeks after dosing. By AAS, Bi levels were highest in olfactory bulb (approximately 7 ppm), hypothalamus (approximately 7 ppm), septum (approximately 3 ppm), and brain stem (approximately 3 ppm). Striatum and cerebral cortex had the least Bi (approximately 1 ppm). Regional distribution by autometallography showed that high Bi levels were associated with diffusion of Bi from fenestrated blood vessels of circumventricular organs and olfactory epithelium. All treated mice had hydrocephalus, but no other pathology was demonstrable by light microscopy. By electron microscopy, dramatic expansion of the extracellular space between choroid plexus epithelial cells was observed. Dendrites in the neuropil of the hypothalamus and septum exhibited vacuoles and membranous debris. Based on the Bi distribution and lesions, we propose that diffusion of Bi from fenestrated blood vessels contributes to pathogenesis of neurotoxicity in mice. This proposal is consistent with the clinical features of Bi-related neurotoxicity in humans.

  13. Mitochondrial dysfunction, impaired oxidative-reduction activity, degeneration, and death in human neuronal and fetal cells induced by low-level exposure to thimerosal and other metal compounds

    PubMed Central

    Geier, D.A.; King, P.G.; Geier, M.R.

    2009-01-01

    Thimerosal (ethylmercurithiosalicylic acid), an ethylmercury (EtHg)-releasing compound (49.55% mercury (Hg)), was used in a range of medical products for more than 70 years. Of particular recent concern, routine administering of Thimerosal-containing biologics/childhood vaccines have become significant sources of Hg exposure for some fetuses/infants. This study was undertaken to investigate cellular damage among in vitro human neuronal (SH-SY-5Y neuroblastoma and 1321N1 astrocytoma) and fetal (nontransformed) model systems using cell vitality assays and microscope-based digital image capture techniques to assess potential damage induced by Thimerosal and other metal compounds (aluminum (Al) sulfate, lead (Pb)(II) acetate, methylmercury (MeHg) hydroxide, and mercury (Hg)(II) chloride) where the cation was reported to exert adverse effects on developing cells. Thimerosal-associated cellular damage was also evaluated for similarity to pathophysiological findings observed in patients diagnosed with autistic disorders (ADs). Thimerosal-induced cellular damage as evidenced by concentration- and time-dependent mitochondrial damage, reduced oxidative–reduction activity, cellular degeneration, and cell death in the in vitro human neuronal and fetal model systems studied. Thimerosal at low nanomolar (nM) concentrations induced significant cellular toxicity in human neuronal and fetal cells. Thimerosal-induced cytoxicity is similar to that observed in AD pathophysiologic studies. Thimerosal was found to be significantly more toxic than the other metal compounds examined. Future studies need to be conducted to evaluate additional mechanisms underlying Thimerosal-induced cellular damage and assess potential co-exposures to other compounds that may increase or decrease Thimerosal-mediated toxicity. PMID:24532866

  14. Potential effects of groundwater pumping on water levels, phreatophytes, and spring discharges in Spring and Snake Valleys, White Pine County, Nevada, and adjacent areas in Nevada and Utah

    USGS Publications Warehouse

    Halford, Keith J.; Plume, Russell W.

    2011-01-01

    Assessing hydrologic effects of developing groundwater supplies in Snake Valley required numerical, groundwater-flow models to estimate the timing and magnitude of capture from streams, springs, wetlands, and phreatophytes. Estimating general water-table decline also required groundwater simulation. The hydraulic conductivity of basin fill and transmissivity of basement-rock distributions in Spring and Snake Valleys were refined by calibrating a steady state, three-dimensional, MODFLOW model of the carbonate-rock province to predevelopment conditions. Hydraulic properties and boundary conditions were defined primarily from the Regional Aquifer-System Analysis (RASA) model except in Spring and Snake Valleys. This locally refined model was referred to as the Great Basin National Park calibration (GBNP-C) model. Groundwater discharges from phreatophyte areas and springs in Spring and Snake Valleys were simulated as specified discharges in the GBNP-C model. These discharges equaled mapped rates and measured discharges, respectively. Recharge, hydraulic conductivity, and transmissivity were distributed throughout Spring and Snake Valleys with pilot points and interpolated to model cells with kriging in geologically similar areas. Transmissivity of the basement rocks was estimated because thickness is correlated poorly with transmissivity. Transmissivity estimates were constrained by aquifer-test results in basin-fill and carbonate-rock aquifers. Recharge, hydraulic conductivity, and transmissivity distributions of the GBNP-C model were estimated by minimizing a weighted composite, sum-of-squares objective function that included measurement and Tikhonov regularization observations. Tikhonov regularization observations were equations that defined preferred relations between the pilot points. Measured water levels, water levels that were simulated with RASA, depth-to-water beneath distributed groundwater and spring discharges, land-surface altitudes, spring discharge at

  15. Prospectives for Gene Therapy of Retinal Degenerations

    PubMed Central

    Thumann, Gabriele

    2012-01-01

    Retinal degenerations encompass a large number of diseases in which the retina and associated retinal pigment epithelial (RPE) cells progressively degenerate leading to severe visual disorders or blindness. Retinal degenerations can be divided into two groups, a group in which the defect has been linked to a specific gene and a second group that has a complex etiology that includes environmental and genetic influences. The first group encompasses a number of relatively rare diseases with the most prevalent being Retinitis pigmentosa that affects approximately 1 million individuals worldwide. Attempts have been made to correct the defective gene by transfecting the appropriate cells with the wild-type gene and while these attempts have been successful in animal models, human gene therapy for these inherited retinal degenerations has only begun recently and the results are promising. To the second group belong glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy (DR). These retinal degenerations have a genetic component since they occur more often in families with affected probands but they are also linked to environmental factors, specifically elevated intraocular pressure, age and high blood sugar levels respectively. The economic and medical impact of these three diseases can be assessed by the number of individuals affected; AMD affects over 30 million, DR over 40 million and glaucoma over 65 million individuals worldwide. The basic defect in these diseases appears to be the relative lack of a neurogenic environment; the neovascularization that often accompanies these diseases has suggested that a decrease in pigment epithelium-derived factor (PEDF), at least in part, may be responsible for the neurodegeneration since PEDF is not only an effective neurogenic and neuroprotective agent but also a potent inhibitor of neovascularization. In the last few years inhibitors of vascularization, especially antibodies against vascular endothelial cell

  16. Two Ultracool Degenerate Companions

    NASA Astrophysics Data System (ADS)

    Farihi, J.

    2005-07-01

    In the course of an extensive survey for low mass stellar and substellar companions to nearby white dwarfs, two extrememly cool degenerate objects have been discovered. GD 392B is one of only a few known white dwarfs with Teff⪉4000 K and exhibits collision induced absorption in the near infrared tep{far04}. GD 1400B is the second known L dwarf companion to a white dwarf and a possible brown dwarf (Farihi & Christopher 2004). Interested readers should consult the references for a complete description of these two cool objects.

  17. Cortical Basal Ganglionic Degeneration

    PubMed Central

    Scarmeas, Nikolaos; Chin, Steven S.; Marder, Karen

    2011-01-01

    In this case study, we describe the symptoms, neuropsychological testing, and brain pathology of a retired mason's assistant with cortical basal ganglionic degeneration (CBGD). CBGD is an extremely rare neurodegenerative disease that is categorized under both Parkinsonian syndromes and frontal lobe dementias. It affects men and women nearly equally, and the age of onset is usually in the sixth decade of life. CBGD is characterized by Parkinson's-like motor symptoms and by deficits of movement and cognition, indicating focal brain pathology. Neuronal cell loss is ultimately responsible for the neurological symptoms. PMID:14602941

  18. Visual system degeneration induced by blast overpressure.

    PubMed

    Petras, J M; Bauman, R A; Elsayed, N M

    1997-07-25

    The effect of blast overpressure on visual system pathology was studied in 14 male Sprague-Dawley rats weighing 360-432 g. Blast overpressure was simulated using a compressed-air driven shock tube, with the aim of studying a range of overpressures causing sublethal injury. Neither control (unexposed) rats nor rats exposed to 83 kiloPascals (kPa) overpressure showed evidence of visual system pathology. Neurological injury to brain visual pathways was observed in male rats surviving blast overpressure exposures of 104-110 kPa and 129-173 kPa. Optic nerve fiber degeneration was ipsilateral to the blast pressure wave. The optic chiasm contained small numbers of degenerated fibers. Optic tract fiber degeneration was present bilaterally, but was predominantly ipsilateral. Optic tract fiber degeneration was followed to nuclear groups at the level of the midbrain, midbrain-diencephalic junction, and the thalamus where degenerated fibers arborized among the neurons of: (i) the superior colliculus, (ii) pretectal region, and (iii) the lateral geniculate body. The superior colliculus contained fiber degeneration localized principally to two superficial layers (i) the stratum opticum (layer III) and (ii) stratum cinereum (layer II). The pretectal area contained degenerated fibers which were widespread in (i) the nucleus of the optic tract, (ii) olivary pretectal nucleus, (iii) anterior pretectal nucleus, and (iv) the posterior pretectal nucleus. Degenerated fibers in the lateral geniculate body were not universally distributed. They appeared to arborize among neurons of the dorsal and ventral nuclei: the ventral lateral geniculate nucleus (parvocellular and magnocellular parts); and the dorsal lateral geniculate nucleus. The axonopathy observed in the central visual pathways and nuclei of the rat brain are consistent with the presence of blast overpressure induced injury to the retina. The orbital cavities of the human skull contain frontally-directed eyeballs for binocular

  19. A measurement of the relative cross sections for simultaneous ionization and excitation of the degenerate He(plus) n equals 4 levels

    NASA Technical Reports Server (NTRS)

    Sutton, J. F.; Kay, R. B.

    1972-01-01

    The relative cross sections for simultaneous ionization and excitation of helium by 200 eV electrons into the 4S, 4P, 4D and 4F levels have been measured via a fast delayed coincidence technique. Results are in poor agreement with Born approximation calculations for simultaneous ionization and excitation of helium, the 4P component being larger than expected.

  20. Does lumbar facet arthrosis precede disc degeneration? A postmortem study.

    PubMed

    Eubanks, Jason David; Lee, Michael J; Cassinelli, Ezequiel; Ahn, Nicholas U

    2007-11-01

    It is believed lumbar degeneration begins in the disc, where desiccation and collapse lead to instability and compensatory facet arthrosis. We explored the contrary contention that facet degeneration precedes disc degeneration by examining 647 skeletal lumbar spines. Using facet osteophytosis as a measure of facet degeneration and vertebral rim osteophytosis as a measure of disc degeneration, we assumed bone degeneration in both locations equally reflected the progression of those in the soft tissues. We graded arthrosis Grade 0 to 4 on a continuum from no arthritis to ankylosis. The data were analyzed for different age groups to examine patterns of degeneration with age. Specimens younger than 30 years of age had a higher prevalence of facet osteophytosis compared with vertebral rim osteophotosis at L1-L2 and L2-L3. Specimens aged 30 to 39 years showed more facet osteophytosis than vertebral rim osteophytosis at L4-L5. Specimens older than 40 years, however, showed more vertebral rim osteophytosis compared with facet osteophytosis at all levels except L4-L5 and L5-S1. This skeletal study suggests facet osteophytosis appears early in the degenerative process, preceding vertebral rim osteophytosis of degenerating intervertebral discs. However, once facets begin deteriorating with age, vertebral rim osteophytosis overtakes continued facet osteophytosis. These data challenge the belief that facet osteophytosis follows vertebral rim osteophytosis; rather, it appears vertebral rim osteophytosis progresses more rapidly in later years, but facet osteophotosis occurs early, predominating in younger individuals.

  1. What Is Age-Related Macular Degeneration?

    MedlinePlus

    ... Degeneration Diagnosis: How is AMD diagnosed? Macular Degeneration Treatment: How is AMD Treated? Macular ... macular degeneration (AMD) is a deterioration or breakdown of the eye's macula. The macula is a small area in the ...

  2. Recombination-generation currents in degenerate semiconductors

    NASA Technical Reports Server (NTRS)

    Von Roos, O.

    1978-01-01

    The classical Shockley-Read-Hall theory of free carrier recombination and generation via traps is extended to degenerate semiconductors. A concise and simple expression is found which avoids completely the concept of a Fermi level, a concept which is alien to nonequilibrium situations. Assumptions made in deriving the recombination generation current are carefully delineated and are found to be basically identical to those made in the original theory applicable to nondegenerate semiconductors.

  3. Degenerate and Resonant Four-Wave Mixing in Plasmas

    NASA Astrophysics Data System (ADS)

    Joshi, C.; Kitagawa, Y.; Lal, A.

    The status of degenerate and resonant four-wave mixing in plasmas is reviewed. For the degenerate case in a collisional plasma, the theory predicts and experiments demonstrate that the thermal-force contribution to the signal reflectivity dominates over the ponderomotive-force contribution. In the resonant case, the reflectivity can be enhanced over the degenerate level. Experiments show that collisions can lead to a narrow spectral width of the ion-acoustic resonance, but the effects of convection and laser heating can limit the enhancement of the reflectivity below the expected value.

  4. Evaluation of Fluoro-Jade C as a marker of degenerating neurons in the rat retina and optic nerve.

    PubMed

    Chidlow, Glyn; Wood, John P M; Sarvestani, Ghafar; Manavis, Jim; Casson, Robert J

    2009-03-01

    Detection of neuronal death is an essential requirement for researchers investigating retinal degeneration. Fluoro-Jade C (FJC) is a novel, fluorescent dye that has been successfully used to label degenerating neurons in the brain, but its effectiveness in the eye has not been ascertained. In the current study, we determined the efficacy of FJC for detection of neuronal degeneration in the retina and optic nerve in various paradigms of injury. N-methyl-D-aspartate (NMDA) and kainic acid-induced excitotoxicity, optic nerve transection, and bilateral occlusion of the common carotid arteries (BCCAO) were performed using standard techniques. Rats were killed at various time points and the retinas with optic nerves attached were removed for tissue processing prior to labelling for FJC, for DNA fragmentation by TUNEL or for immunohistochemical analysis. Retinas from RCS rats of different ages were also analysed. After excitotoxicity-induced injury, cell bodies and dendrites within the ganglion cell and inner plexiform layers were specifically labelled by FJC within 6h, a time point comparable to the appearance of TUNEL-positive nuclei and to reductions in mRNA levels of retinal ganglion cell-specific proteins, but in advance of alterations in some immunohistochemical markers. The number of FJC-labelled cell bodies in the retina declined over time as cell loss proceeded, although dendritic staining remained prominent. Colocalisation of FJC with TUNEL and with immunohistochemical neuronal markers was achieved. FJC was successful at identifying somato-dendritic degeneration following ischemia induced by BCCAO, but surprisingly, not after optic nerve transection. FJC visualised photoreceptor degeneration in the RCS rat, albeit less effectively than with the TUNEL assay, and was also effective for imaging and quantifying degenerating axons in the optic nerve after multiple injuries. In addition to labelling degenerating neurons, however, FJC also bound non-specifically to

  5. Wilson's disease (hepatolenticular degeneration).

    PubMed

    Herron, B E

    1976-01-01

    Wilson's disease, or hepatolenticular degeneration, is a rare inherited disorder of copper metabolism which usually affects young people. Excess copper accumulates in the tissues, primarily in the liver, brain, and cornea. This copper deposition results in a wide range of hepatic and neurological symptoms, and may produce psychiatric illness. Hepatic involvement often occurs in childhood, while neurological deficits generally are detected at a later age. The disease is inherited in an autosomal recessive fashion. Ocular findings are of particular importance because the corneal copper deposition, forming the Kayser-Fleischer ring,is the only pathognomonic sign of the disease. The structure of the ring and the presence of copper have been well established. An anterior capsular deposition of copper in the lens results in a characteristic sunflower cataract in some of these patients. Other ocular abnormalities have been described but are much less common. The pathogenesis of the disease and the basic genetic defect remain obscure. It is clear that there is excess copper in the tissues, but the mechanism of its deposition is unknown. It is in some way associated with a failure to synthesize the serum copper protein ceruloplasmin normally. Another theory suggests that an abnormal protein with a high affinity for copper may bind the metal in the tissues. The diagnosis may be suggested by the clinical manifestations and confirmed by the presence of a Kayser-Fleischer ring. In the absence of these findings biochemical determinations are necessary. The most important of these are the serum ceruloplasmin, the urinary copper, and the hepatic copper concentration on biopsy. Treatment consists in the administration of the copper chelating agent, penicillamine, and the avoidance of a high copper intake. This usually results in marked clinical improvement if irreversible tissue damage has not occurred. Maintenance therapy for life is necessary in order to continue the negative

  6. [New drug therapy for retinal degeneration].

    PubMed

    Ohguro, Hiroshi

    2008-01-01

    Retinitis pigmentosa (RP) is an inherited retinal degeneration characterized by nyctalopia, ring scotoma, and bone-spicule pigmentation of the retina. So far, no effective therapy has been found for RP. As a possible molecular etiology of RP, retina-specific gene deficits are most likely involved, but little has been identified in terms of intracellular mechanisms leading to retinal photoreceptor cell death at post-translational levels. In order to find an effective therapy for RP, we must look for underlying common mechanisms that are responsible for the development of RP, instead of designing a specific therapy for each of the RP types with different causes. Therefore, in the present study, several animal models with different causes of RP were studied, including (1)Royal College of Surgeons (RCS) rats with a deficit of retinal pigment epithelium (RPE) function caused by rhodopsin mutation; (2) P23H rats, (3) S334ter rats, (4) photo stress rats, (5) retinal degeneration (rd) mice with a deficit of phosphodiesterase(PDE) function; and (6) cancer-associated retinopathy (CAR) model rats with a deficit of recoverin-dependent photoreceptor adaptation function. In each of these models, the following assessments were made in order to elucidate common pathological mechanisms among the models: (1) retinal function assessed by electroretinogram (ERG), (2) retinal morphology, (3) retinoid analysis, (4) rhodopsin regeneration, (5) rhodopsin phosphorylation and dephosphorylation, and (6) cytosolic cGMP levels. We found that unregulated photoreceptor adaptation processes caused by an imbalance of rhodopsin phosphorylation and dephosphorylation caused retinal dysfunction leading to photoreceptor cell death. As possible candidate drugs for normalizing these retinal dysfunctions and stopping further retinal degeneration, nilvadipine, a Ca channel blocker, retinoid derivatives, and anthocyanine were chosen and tested to determine their effect on the above animal models with

  7. Molecular disorganization of axons adjacent to human lacunar infarcts.

    PubMed

    Hinman, Jason D; Lee, Monica D; Tung, Spencer; Vinters, Harry V; Carmichael, S Thomas

    2015-03-01

    increased. Myelin basic protein and neurofilament immunolabelling demonstrates that axons in these adjacent regions have preserved axonal cytoskeleton organization and are generally myelinated. This indicates that the loss of normal axonal microdomain architecture results from disrupted axoglial signalling in white matter adjacent to lacunar and microinfarcts. The loss of the normal molecular organization of nodes and paranodes is associated with axonal degeneration and may lead to impaired conduction velocity across surviving axons after stroke. These findings demonstrate that the degree of white matter injury associated with cerebral microvascular disease extends well beyond what can be identified using imaging techniques and that an improved understanding of the neurobiology in these regions can drive new therapeutic strategies for this disease entity. PMID:25614025

  8. Molecular disorganization of axons adjacent to human lacunar infarcts

    PubMed Central

    Lee, Monica D.; Tung, Spencer; Vinters, Harry V.; Carmichael, S. Thomas

    2015-01-01

    increased. Myelin basic protein and neurofilament immunolabelling demonstrates that axons in these adjacent regions have preserved axonal cytoskeleton organization and are generally myelinated. This indicates that the loss of normal axonal microdomain architecture results from disrupted axoglial signalling in white matter adjacent to lacunar and microinfarcts. The loss of the normal molecular organization of nodes and paranodes is associated with axonal degeneration and may lead to impaired conduction velocity across surviving axons after stroke. These findings demonstrate that the degree of white matter injury associated with cerebral microvascular disease extends well beyond what can be identified using imaging techniques and that an improved understanding of the neurobiology in these regions can drive new therapeutic strategies for this disease entity. PMID:25614025

  9. Posterior lumbar dynamic stabilization instead of arthrodesis for symptomatic adjacent-segment degenerative stenosis: description of a novel technique.

    PubMed

    Mashaly, Hazem; Paschel, Erin E; Khattar, Nicolas K; Goldschmidt, Ezequiel; Gerszten, Peter C

    2016-01-01

    OBJECTIVE The development of symptomatic adjacent-segment disease (ASD) is a well-recognized consequence of lumbar fusion surgery. Extension of a fusion to a diseased segment may only lead to subsequent adjacent-segment degeneration. The authors report the use of a novel technique that uses dynamic stabilization instead of arthrodesis for the surgical treatment of symptomatic ASD following a prior lumbar instrumented fusion. METHODS A cohort of 28 consecutive patients was evaluated who developed symptomatic stenosis immediately adjacent to a previous lumbar instrumented fusion. All patients had symptoms of neurogenic claudication refractory to nonsurgical treatment and were surgically treated with decompression and dynamic stabilization instead of extending the fusion construct using a posterior lumbar dynamic stabilization system. Preoperative symptoms, visual analog scale (VAS) pain scores, and perioperative complications were recorded. Clinical outcome was gauged by comparing VAS scores prior to surgery and at the time of last follow-up. RESULTS The mean follow-up duration was 52 months (range 17-94 months). The mean interval from the time of primary fusion surgery to the dynamic stabilization surgery was 40 months (range 10-96 months). The mean patient age was 51 years (range 29-76 years). There were 19 (68%) men and 9 (32%) women. Twenty-three patients (82%) presented with low-back pain at time of surgery, whereas 24 patients (86%) presented with lower-extremity symptoms only. Twenty-four patients (86%) underwent operations that were performed using single-level dynamic stabilization, 3 patients (11%) were treated at 2 levels, and 1 patient underwent 3-level decompression and dynamic stabilization. The most commonly affected and treated level (46%) was L3-4. The mean preoperative VAS pain score was 8, whereas the mean postoperative score was 3. No patient required surgery for symptomatic degeneration rostral to the level of dynamic stabilization during the

  10. Posterior lumbar dynamic stabilization instead of arthrodesis for symptomatic adjacent-segment degenerative stenosis: description of a novel technique.

    PubMed

    Mashaly, Hazem; Paschel, Erin E; Khattar, Nicolas K; Goldschmidt, Ezequiel; Gerszten, Peter C

    2016-01-01

    OBJECTIVE The development of symptomatic adjacent-segment disease (ASD) is a well-recognized consequence of lumbar fusion surgery. Extension of a fusion to a diseased segment may only lead to subsequent adjacent-segment degeneration. The authors report the use of a novel technique that uses dynamic stabilization instead of arthrodesis for the surgical treatment of symptomatic ASD following a prior lumbar instrumented fusion. METHODS A cohort of 28 consecutive patients was evaluated who developed symptomatic stenosis immediately adjacent to a previous lumbar instrumented fusion. All patients had symptoms of neurogenic claudication refractory to nonsurgical treatment and were surgically treated with decompression and dynamic stabilization instead of extending the fusion construct using a posterior lumbar dynamic stabilization system. Preoperative symptoms, visual analog scale (VAS) pain scores, and perioperative complications were recorded. Clinical outcome was gauged by comparing VAS scores prior to surgery and at the time of last follow-up. RESULTS The mean follow-up duration was 52 months (range 17-94 months). The mean interval from the time of primary fusion surgery to the dynamic stabilization surgery was 40 months (range 10-96 months). The mean patient age was 51 years (range 29-76 years). There were 19 (68%) men and 9 (32%) women. Twenty-three patients (82%) presented with low-back pain at time of surgery, whereas 24 patients (86%) presented with lower-extremity symptoms only. Twenty-four patients (86%) underwent operations that were performed using single-level dynamic stabilization, 3 patients (11%) were treated at 2 levels, and 1 patient underwent 3-level decompression and dynamic stabilization. The most commonly affected and treated level (46%) was L3-4. The mean preoperative VAS pain score was 8, whereas the mean postoperative score was 3. No patient required surgery for symptomatic degeneration rostral to the level of dynamic stabilization during the

  11. MRI evaluation of spontaneous intervertebral disc degeneration in the alpaca cervical spine.

    PubMed

    Stolworthy, Dean K; Bowden, Anton E; Roeder, Beverly L; Robinson, Todd F; Holland, Jacob G; Christensen, S Loyd; Beatty, Amanda M; Bridgewater, Laura C; Eggett, Dennis L; Wendel, John D; Stieger-Vanegas, Susanne M; Taylor, Meredith D

    2015-12-01

    Animal models have historically provided an appropriate benchmark for understanding human pathology, treatment, and healing, but few animals are known to naturally develop intervertebral disc degeneration. The study of degenerative disc disease and its treatment would greatly benefit from a more comprehensive, and comparable animal model. Alpacas have recently been presented as a potential large animal model of intervertebral disc degeneration due to similarities in spinal posture, disc size, biomechanical flexibility, and natural disc pathology. This research further investigated alpacas by determining the prevalence of intervertebral disc degeneration among an aging alpaca population. Twenty healthy female alpacas comprised two age subgroups (5 young: 2-6 years; and 15 older: 10+ years) and were rated according to the Pfirrmann-grade for degeneration of the cervical intervertebral discs. Incidence rates of degeneration showed strong correlations with age and spinal level: younger alpacas were nearly immune to developing disc degeneration, and in older animals, disc degeneration had an increased incidence rate and severity at lower cervical levels. Advanced disc degeneration was present in at least one of the cervical intervertebral discs of 47% of the older alpacas, and it was most common at the two lowest cervical intervertebral discs. The prevalence of intervertebral disc degeneration encourages further investigation and application of the lower cervical spine of alpacas and similar camelids as a large animal model of intervertebral disc degeneration.

  12. Genetic Association Studies in Lumbar Disc Degeneration: A Systematic Review

    PubMed Central

    Eskola, Pasi J.; Lemmelä, Susanna; Kjaer, Per; Solovieva, Svetlana; Männikkö, Minna; Tommerup, Niels; Lind-Thomsen, Allan; Husgafvel-Pursiainen, Kirsti; Cheung, Kenneth M. C.; Chan, Danny

    2012-01-01

    Objective Low back pain is associated with lumbar disc degeneration, which is mainly due to genetic predisposition. The objective of this study was to perform a systematic review to evaluate genetic association studies in lumbar disc degeneration as defined on magnetic resonance imaging (MRI) in humans. Methods A systematic literature search was conducted in MEDLINE, MEDLINE In-Process, SCOPUS, ISI Web of Science, The Genetic Association Database and The Human Genome Epidemiology Network for information published between 1990–2011 addressing genes and lumbar disc degeneration. Two investigators independently identified studies to determine inclusion, after which they performed data extraction and analysis. The level of cumulative genetic association evidence was analyzed according to The HuGENet Working Group guidelines. Results Fifty-two studies were included for review. Forty-eight studies reported at least one positive association between a genetic marker and lumbar disc degeneration. The phenotype definition of lumbar disc degeneration was highly variable between the studies and replications were inconsistent. Most of the associations presented with a weak level of evidence. The level of evidence was moderate for ASPN (D-repeat), COL11A1 (rs1676486), GDF5 (rs143383), SKT (rs16924573), THBS2 (rs9406328) and MMP9 (rs17576). Conclusions Based on this first extensive systematic review on the topic, the credibility of reported genetic associations is mostly weak. Clear definition of lumbar disc degeneration phenotypes and large population-based cohorts are needed. An international consortium is needed to standardize genetic association studies in relation to disc degeneration. PMID:23185509

  13. Age-Related Macular Degeneration.

    PubMed

    Mehta, Sonia

    2015-09-01

    Age-related macular degeneration (AMD) is the leading cause of vision loss in the elderly. AMD is diagnosed based on characteristic retinal findings in individuals older than 50. Early detection and treatment are critical in increasing the likelihood of retaining good and functional vision.

  14. Does lumbar spinal degeneration begin with the anterior structures? A study of the observed epidemiology in a community-based population

    PubMed Central

    2011-01-01

    Background- Prior studies that have concluded that disk degeneration uniformly precedes facet degeneration have been based on convenience samples of individuals with low back pain. We conducted a study to examine whether the view that spinal degeneration begins with the anterior spinal structures is supported by epidemiologic observations of degeneration in a community-based population. Methods- 361 participants from the Framingham Heart Study were included in this study. The prevalences of anterior vertebral structure degeneration (disk height loss) and posterior vertebral structure degeneration (facet joint osteoarthritis) were characterized by CT imaging. The cohort was divided into the structural subgroups of participants with 1) no degeneration, 2) isolated anterior degeneration (without posterior degeneration), 3) combined anterior and posterior degeneration, and 4) isolated posterior degeneration (without anterior structure degeneration). We determined the prevalence of each degeneration pattern by age group < 45, 45-54, 55-64, ≥65. In multivariate analyses we examined the association between disk height loss and the response variable of facet joint osteoarthritis, while adjusting for age, sex, BMI, and smoking. Results- As the prevalence of the no degeneration and isolated anterior degeneration patterns decreased with increasing age group, the prevalence of the combined anterior/posterior degeneration pattern increased. 22% of individuals demonstrated isolated posterior degeneration, without an increase in prevalence by age group. Isolated posterior degeneration was most common at the L5-S1 and L4-L5 spinal levels. In multivariate analyses, disk height loss was independently associated with facet joint osteoarthritis, as were increased age (years), female sex, and increased BMI (kg/m2), but not smoking. Conclusions- The observed epidemiology of lumbar spinal degeneration in the community-based population is consistent with an ordered progression beginning

  15. Ataxias and Cerebellar or Spinocerebellar Degeneration

    MedlinePlus

    ... Awards Enhancing Diversity Find People About NINDS NINDS Ataxias and Cerebellar or Spinocerebellar Degeneration Information Page Synonym(s): ... Publications and Information Publicaciones en Español What are Ataxias and Cerebellar or Spinocerebellar Degeneration? Ataxia often occurs ...

  16. Age-associated mosaic respiratory chain deficiency causes trans-neuronal degeneration.

    PubMed

    Dufour, Eric; Terzioglu, Mügen; Sterky, Fredrik Hansson; Sörensen, Lene; Galter, Dagmar; Olson, Lars; Wilbertz, Johannes; Larsson, Nils-Göran

    2008-05-15

    Heteroplasmic mitochondrial DNA (mtDNA) mutations (mutations present only in a subset of cellular mtDNA copies) arise de novo during the normal ageing process or may be maternally inherited in pedigrees with mitochondrial disease syndromes. A pathogenic mtDNA mutation causes respiratory chain deficiency only if the fraction of mutated mtDNA exceeds a certain threshold level. These mutations often undergo apparently random mitotic segregation and the levels of normal and mutated mtDNA can vary considerably between cells of the same tissue. In human ageing, segregation of somatic mtDNA mutations leads to mosaic respiratory chain deficiency in a variety of tissues, such as brain, heart and skeletal muscle. A similar pattern of mutation segregation with mosaic respiratory chain deficiency is seen in patients with mitochondrial disease syndromes caused by inherited pathogenic mtDNA mutations. We have experimentally addressed the role of mosaic respiratory chain deficiency in ageing and mitochondrial disease by creating mouse chimeras with a mixture of normal and respiratory chain-deficient neurons in cerebral cortex. We report here that a low proportion (>20%) of respiratory chain-deficient neurons in the forebrain are sufficient to cause symptoms, whereas premature death of the animal occurs only if the proportion is high (>60-80%). The presence of neurons with normal respiratory chain function does not only prevent mortality but also delays the age at which onset of disease symptoms occur. Unexpectedly, respiratory chain-deficient neurons have adverse effect on normal adjacent neurons and induce trans-neuronal degeneration. In summary, our study defines the minimal threshold level of respiratory chain-deficient neurons needed to cause symptoms and also demonstrate that neurons with normal respiratory chain function ameliorate disease progression. Finally, we show that respiratory chain-deficient neurons induce death of normal neurons by a trans-neuronal degeneration

  17. Lumbar intervertebral disc degeneration and related factors in Korean firefighters

    PubMed Central

    Jang, Tae-Won; Ahn, Yeon-Soon; Byun, Junsu; Lee, Jong-In; Kim, Kun-Hyung; Kim, Youngki; Song, Han-Soo; Lee, Chul-Gab; Kwon, Young-Jun; Yoon, Jin-Ha; Jeong, Kyoungsook

    2016-01-01

    Objectives The job of firefighting can cause lumbar burden and low back pain. This study aimed to identify the association between age and lumbar intervertebral disc degeneration and whether the association differs between field and administrative (non-field) firefighters. Methods Subjects were selected using a stratified random sampling method. Firefighters were stratified by geographic area, gender, age and type of job. First, 25 fire stations were randomly sampled considering regional distribution. Then firefighters were stratified by gender, age and their job and randomly selected among the strata. A questionnaire survey and MRI scans were performed, and then four radiologists used Pfirrmann classification methods to determine the grade of lumbar intervertebral disc degeneration. Results Pfirrmann grade increased with lumbar intervertebral disc level. Analysis of covariance showed that age was significantly associated with lumbar intervertebral disc degeneration (p<0.05). The value of β (parameter estimate) was positive at all lumbar intervertebral disc levels and was higher in the field group than in the administrative group at each level. In logistic regression analysis, type of job was statistically significant only with regard to the L4–5 intervertebral disc (OR 3.498, 95% CI 1.241 to 9.860). Conclusions Lumbar intervertebral disc degeneration is associated with age, and field work such as firefighting, emergency and rescue may accelerate degeneration in the L4–5 intervertebral disc. The effects of field work on lumbar intervertebral disc degeneration were not clear in discs other than at the level L4–5. PMID:27354080

  18. Reconstitution of degenerated ovine lumbar discs by STRO-3-positive allogeneic mesenchymal precursor cells combined with pentosan polysulfate.

    PubMed

    Oehme, David; Ghosh, Peter; Goldschlager, Tony; Itescu, Silviu; Shimon, Susan; Wu, Jiehua; McDonald, Courtney; Troupis, John M; Rosenfeld, Jeffrey V; Jenkin, Graham

    2016-05-01

    OBJECTIVE Disc degeneration and associated low-back pain are major causes of suffering and disability. The authors examined the potential of mesenchymal precursor cells (MPCs), when formulated with pentosan polysulfate (PPS), to ameliorate disc degeneration in an ovine model. METHODS Twenty-four sheep had annular incisions made at L2-3, L3-4, and L4-5 to induce degeneration. Twelve weeks after injury, the nucleus pulposus of a degenerated disc in each animal was injected with ProFreeze and PPS formulated with either a low dose (0.1 million MPCs) or a high dose (0.5 million MPCs) of cells. The 2 adjacent injured discs in each spine were either injected with PPS and ProFreeze (PPS control) or not injected (nil-injected control). The adjacent noninjured L1-2 and L5-6 discs served as noninjured control discs. Disc height indices (DHIs) were obtained at baseline, before injection, and at planned death. After necropsy, 24 weeks after injection, the spines were subjected to MRI and morphological, histological, and biochemical analyses. RESULTS Twelve weeks after the annular injury, all the injured discs exhibited a significant reduction in mean DHI (low-dose group 17.19%; high-dose group 18.01% [p < 0.01]). Twenty-four weeks after injections, the discs injected with the low-dose MPC+PPS formulation recovered disc height, and their mean DHI was significantly greater than the DHI of PPS- and nil-injected discs (p < 0.001). Although the mean Pfirrmann MRI disc degeneration score for the low-dose MPC+PPS-injected discs was lower than that for the nil- and PPS-injected discs, the differences were not significant. The disc morphology scores for the nil- and PPS-injected discs were significantly higher than the normal control disc scores (p < 0.005), whereas the low-dose MPC+PPS-injected disc scores were not significantly different from those of the normal controls. The mean glycosaminoglycan content of the nuclei pulposus of the low-dose MPC+PPS-injected discs was significantly

  19. Degenerating the elliptic Schlesinger system

    NASA Astrophysics Data System (ADS)

    Aminov, G. A.; Artamonov, S. B.

    2013-01-01

    We study various ways of degenerating the Schlesinger system on the elliptic curve with R marked points. We construct a limit procedure based on an infinite shift of the elliptic curve parameter and on shifts of the marked points. We show that using this procedure allows obtaining a nonautonomous Hamiltonian system describing the Toda chain with additional spin sl(N, ℂ) degrees of freedom.

  20. Degenerative disease supra- and infra-jacent to fused lumbar and lumbo-sacral levels.

    PubMed

    Rousseau, M-A; Lazennec, J-Y

    2016-02-01

    Disc degeneration is a normal age-related process. Accelerated degeneration of discs adjacent to fused spinal levels has been observed in numerous case-series studies. The available data document this phenomenon and provide information on its time to occurrence but show huge variations in incidence rates (5% to 70%). The supra-jacent disc is involved more often than the infra-jacent disc. Studies have clarified the underlying biomechanical rationale by showing increased loading of the adjacent discs. Risk factors have been the focus of the most recent studies. They include the number of fused levels, sagittal alignment, level of fusion, stiffness of the construct, and integrity of the posterior structures. Nevertheless, the many published studies have produced somewhat conflicting results. Various radiological criteria have been used to define degeneration of the adjacent disc. Although most patients have no symptoms, adverse effects on the spine and/or nerve roots may occur and, in some cases, require revision surgery. We draw attention to the many sources of bias in the published studies, of which we provide a critical and pragmatic discussion in the light of our personal experience. PMID:26797007

  1. Light scattering of degenerate fermions

    NASA Astrophysics Data System (ADS)

    Aubin, S.; Leblanc, L. J.; Myrskog, S.; Extavour, M. H. T.; McKay, D.; Stummer, A.; Thywissen, J. H.

    2006-05-01

    We report on progress in measuring the suppression of resonant light scattering in a gas of degenerate fermions. A gas of trapped degenerate fermions is expected to exhibit narrower optical linewidths and longer excited state lifetimes than single atoms when the Fermi energy is larger than the photon recoil energy [1-3]. In this case, the number of available states into which a scattered atom can recoil is significantly reduced due to the filling of the Fermi sea. We produce a degenerate gas of 4x10^4 ultra-cold fermionic ^40K atoms by sympathetic cooling with bosonic ^87Rb in a micro-magnetic chip trap. The atoms can then be loaded into a tight dipole trap just above the surface of the chip and probed with a near resonance laser pulse. [1] Th. Busch, J. R. Anglin, J. I. Cirac, and P. Zoller, Europhys. Lett. 44, 1 (1998). [2] B. DeMarco and D. S. Jin, Phys. Rev. A 58, R4267 (1998). [3] J. Javanainen and J. Ruostekosky, Phys. Rev. A 52, 3033 (1995). Work supported by NSERC, CFI, OIT, Research Corporation, and PRO.

  2. Radiologic Changes of Operated and Adjacent Segments after Anterior Cervical Microforaminotomy

    PubMed Central

    Ahn, Jang Ho; Park, Moon Sun; Kim, Seong Min; Chung, Seung Young; Lee, Do Sung

    2016-01-01

    Objective Anterior cervical microforaminotomy (ACMF) is a motion-preserving surgical procedure. The purpose of this study is to assess radiologic changes of operated and adjacent segments after ACMF. Methods We retrospectively reviewed 52 patients who underwent ACMF between 1998 and 2008. From X-ray film-based changes, disc height and sagittal range of motion (ROM) of operated and adjacent segments were compared at preoperative and last follow-up periods. Radiological degeneration of both segments was analyzed as well. Results The mean follow-up period was 48.2 months. There were 78 operated, 52 upper adjacent, and 38 lower adjacent segments. There were statistically significant differences in the ROM and disc height of operated segment between preoperative and last follow-up periods. However, there were no statistically significant differences in the ROM and disc height of adjacent segment between both periods. Radiological degenerative changes of operated segments were observed in 30%. That of adjacent segments was observed in 11 and 11% at upper and lower segments, respectively. Conclusion After mean 4-year follow-up periods, there were degenerative changes of operated segments. However, ACMF preserved motion and prevented degenerative changes of adjacent segments. PMID:27799993

  3. RP cone-rod degeneration.

    PubMed Central

    Heckenlively, J R

    1987-01-01

    A group of patients with progressive retinal degeneration and visual field loss, who meet the basic definition of RP were investigated to better define the relationship of the findings on the ERG with clinical characteristics such as visual field size, presence or absence of scotomata or pseudo-altitudinal defects on visual field, amount of night blindness; and presence or absence of macular or optic nerve changes. These studies suggest that cone-rod degeneration patients of the RP type go through the following stages; early, the ERG has a definite cone-rod pattern where the rod ERG is larger than the cone ERG while both are abnormal. As the disease advances, there is more of a reduction in the scotopic ERG such that both the rod and cone ERGs become nearly equal. As the disease further progresses the ERG becomes non-recordable on single-flash technique, but there is good residual rod function and the final rod threshold remains good until the visual field is reduced, typically less than 10 degrees with the IV-4 isopter. Finally with advanced disease the patient becomes night blind and generally becomes very difficult to distinguished from patients who have advanced rod-cone degeneration. While it may seem logical to find that visual field size correlates with various ERG parameters; this has not been as consistent a finding in patients with rod-cone degeneration in the author's experience. The analysis shows several new pieces of information about visual field changes in cone-rod degeneration; enlarged blind spots are seen earlier in cases which have recordable cone-rod patterns (group I), and pseudo-altitudinal changes are more likely to occur in autosomal recessive patients. Patients with macular lesions and central scotomata had larger amplitudes than patients with normal appearing maculae and no central scotomata. Patients with temporal optic atrophy had an earlier onset of symptoms and significant correlation with both photopic a- and b-waves and bright flash

  4. Extended Hellmann-Feynman theorem for degenerate eigenstates

    NASA Astrophysics Data System (ADS)

    Zhang, G. P.; George, Thomas F.

    2004-04-01

    In a previous paper, we reported a failure of the traditional Hellmann-Feynman theorem (HFT) for degenerate eigenstates. This has generated enormous interest among different groups. In four independent papers by Fernandez, by Balawender, Hola, and March, by Vatsya, and by Alon and Cederbaum, an elegant method to solve the problem was devised. The main idea is that one has to construct and diagonalize the force matrix for the degenerate case, and only the eigenforces are well defined. We believe this is an important extension to HFT. Using our previous example for an energy level of fivefold degeneracy, we find that those eigenforces correctly reflect the symmetry of the molecule.

  5. Awareness, Knowledge, and Concern about Age-Related Macular Degeneration

    ERIC Educational Resources Information Center

    Cimarolli, Verena R.; Laban-Baker, Allie; Hamilton, Wanda S.; Stuen, Cynthia

    2012-01-01

    Age-related macular degeneration (AMD)--a common eye disease causing vision loss--can be detected early through regular eye-health examinations, and measures can be taken to prevent visual decline. Getting eye examinations requires certain levels of awareness, knowledge, and concern related to AMD. However, little is known about AMD-related…

  6. Genetics, Pregnancy, and Aortic Degeneration.

    PubMed

    Crawford, Jeffrey D; Hsieh, Cindy M; Schenning, Ryan C; Slater, Matthew S; Landry, Gregory J; Moneta, Gregory L; Mitchell, Erica L

    2016-01-01

    We present a case of familial thoracic aortic aneurysm and dissection (FTAAD) in a pregnant female. FTAAD is an inherited, nonsyndromic aortopathy resulting from several genetic mutations critical to aortic wall integrity have been identified. One such mutation is the myosin heavy chain gene (MYH11) which is responsible for 1-2% of all FTAAD cases. This mutation results in aortic medial degeneration, loss of elastin, and reticulin fiber fragmentation predisposing to TAAD. Aortic disease is more aggressive during pregnancy as a result of increased wall stress from hyperdynamic cardiovascular changes and estrogen-induced aortic media degeneration. Our patient was a 29-year-old G2P1 woman at 26 weeks gestation presenting with abdominal and back pain. Work-up revealed a 6.4-cm ascending aortic aneurysm with a type A dissection extending into all arch vessels, aortic coarctation at the isthmus, and a separate focal type B aortic dissection with visceral involvement. Surgical management included concomitant cesarean section with delivery of a live premature infant, tubal ligation, ascending aortic replacement with reconstruction of the arch vessels, and aortic valve resuspension. The type B dissection was managed medically without complication. This is the first reported case of aortic dissection in a patient with FTAAD/MYH11 mutation and pregnancy. This case highlights that FTAAD and pregnancy cause aortic degeneration via distinct mechanisms and that hyperdynamics of pregnancy increase aortic wall stress. Management of pregnancy associated with aortopathy requires early transfer to a tertiary center, careful investigation to identify familial aortopathy, fetal monitoring, and a multidisciplinary team approach. PMID:26381327

  7. Degeneration of a Nonrecombining Chromosome

    NASA Astrophysics Data System (ADS)

    Rice, William R.

    1994-01-01

    Comparative studies suggest that sex chromosomes begin as ordinary autosomes that happen to carry a major sex determining locus. Over evolutionary time the Y chromosome is selected to stop recombining with the X chromosome, perhaps in response to accumulation of alleles beneficial to the heterogametic but harmful to the homogametic sex. Population genetic theory predicts that a nonrecombining Y chromosome should degenerate. Here this prediction is tested by application of specific selection pressures to Drosophila melanogaster populations. Results demonstrate the decay of a nonrecombining, nascent Y chromosome and the capacity for recombination to ameliorate such decay.

  8. Mathematical glimpse on the Y chromosome degeneration

    NASA Astrophysics Data System (ADS)

    Lobo, M. P.

    2006-04-01

    The Y chromosomes are genetically degenerate and do not recombine with their matching partners X. Non-recombination of XY pairs has been pointed out as the key factor for the degeneration of the Y chromosome. The aim here is to show that there is a mathematical asymmetry in sex chromosomes which leads to the degeneration of Y chromosomes even in the absence of XX and XY recombination. A model for sex-chromosome evolution in a stationary regime is proposed. The consequences of their asymmetry are analyzed and lead us to a couple of conclusions. First, Y chromosome degeneration shows up sqrt{2} more often than X chromosome degeneration. Second, if nature prohibits female mortalities from beeing exactly 50%, then Y chromosome degeneration is inevitable.

  9. Axon degeneration: context defines distinct pathways.

    PubMed

    Geden, Matthew J; Deshmukh, Mohanish

    2016-08-01

    Axon degeneration is an essential part of development, plasticity, and injury response and has been primarily studied in mammalian models in three contexts: 1) Axotomy-induced Wallerian degeneration, 2) Apoptosis-induced axon degeneration (axon apoptosis), and 3) Axon pruning. These three contexts dictate engagement of distinct pathways for axon degeneration. Recent advances have identified the importance of SARM1, NMNATs, NAD+ depletion, and MAPK signaling in axotomy-induced Wallerian degeneration. Interestingly, apoptosis-induced axon degeneration and axon pruning have many shared mechanisms both in signaling (e.g. DLK, JNKs, GSK3α/β) and execution (e.g. Puma, Bax, caspase-9, caspase-3). However, the specific mechanisms by which caspases are activated during apoptosis versus pruning appear distinct, with apoptosis requiring Apaf-1 but not caspase-6 while pruning requires caspase-6 but not Apaf-1. PMID:27197022

  10. On the Computational Complexity of Degenerate Unit Distance Representations of Graphs

    NASA Astrophysics Data System (ADS)

    Horvat, Boris; Kratochvíl, Jan; Pisanski, Tomaž

    Some graphs admit drawings in the Euclidean k-space in such a (natural) way, that edges are represented as line segments of unit length. Such embeddings are called k-dimensional unit distance representations. The embedding is strict if the distances of points representing nonadjacent pairs of vertices are different than 1. When two non-adjacent vertices are drawn in the same point, we say that the representation is degenerate. Computational complexity of nondegenerate embeddings has been studied before. We initiate the study of the computational complexity of (possibly) degenerate embeddings. In particular we prove that for every k ≥ 2, deciding if an input graph has a (possibly) degenerate k-dimensional unit distance representation is NP-hard.

  11. [Age-related macular degeneration].

    PubMed

    Garcia Layana, A

    1998-01-01

    Age-related macular degeneration (ARMD) is the leading cause of blindness in the occidental world. Patients suffering this process have an important reduction on their quality of life being handicapped to read, to write, to recognise faces of their friends, or even to watch the television. One of the main problems of that disease is the absence of an effective treatment able to revert the process. Laser treatment is only useful in a limited number of patients, and even in these cases recurrent lesions are frequent. These facts and the progressive ageing of our society establish the ARMD as one of the biggest aim of medical investigations for the next century, and currently is focus of attention in the most industrialised countries. One of the most promising pieces of research is focused in the investigation of the risk factors associated with the age-related macular degeneration, in order to achieve a prophylactic treatment avoiding its appearance. Diet elements such as fat ingestion or reduced antioxidant intakes are being investigated as some of these factors, what open a new possibility for a prophylactic treatment. Finally, research is looking for new therapeutic modalities such as selective radiotherapy in order to improve or maintain the vision of these patients.

  12. Signaling mechanisms regulating Wallerian degeneration

    PubMed Central

    Freeman, Marc R.

    2014-01-01

    Summary Wallerian degeneration (WD) occurs after an axon is cut or crushed and entails the disintegration and clearance of the severed axon distal to the injury site. WD was initially thought to result from the passive wasting away of the distal axonal fragment, presumably because it lacked a nutrient supply from the cell body. The discovery of the slow Wallerian degeneration (Wlds) mutant mouse, in which distal severed axons survive intact for weeks rather than only 1–2 days, radically changed our thoughts on the autonomy of axon survival. Wlds taught us that under some conditions the axonal compartment can survive for weeks after axotomy without a cell body. The phenotypic and molecular characterization of Wlds and current models for Wlds molecular function are reviewed herein—the mechanism(s) by which WldS spares severed axons remains unresolved. However, recent studies inspired by Wlds have led to the identification of the first “axon death” signaling molecules whose endogenous activities promote axon destruction during WD. PMID:24907513

  13. Parainflammation, chronic inflammation, and age-related macular degeneration.

    PubMed

    Chen, Mei; Xu, Heping

    2015-11-01

    Inflammation is an adaptive response of the immune system to noxious insults to maintain homeostasis and restore functionality. The retina is considered an immune-privileged tissue as a result of its unique anatomic and physiologic properties. During aging, the retina suffers from a low-grade chronic oxidative insult, which sustains for decades and increases in level with advancing age. As a result, the retinal innate-immune system, particularly microglia and the complement system, undergoes low levels of activation (parainflammation). In many cases, this parainflammatory response can maintain homeostasis in the healthy aging eye. However, in patients with age-related macular degeneration, this parainflammatory response becomes dysregulated and contributes to macular damage. Factors contributing to the dysregulation of age-related retinal parainflammation include genetic predisposition, environmental risk factors, and old age. Dysregulated parainflammation (chronic inflammation) in age-related macular degeneration damages the blood retina barrier, resulting in the breach of retinal-immune privilege, leading to the development of retinal lesions. This review discusses the basic principles of retinal innate-immune responses to endogenous chronic insults in normal aging and in age-related macular degeneration and explores the difference between beneficial parainflammation and the detrimental chronic inflammation in the context of age-related macular degeneration.

  14. 4. Elevation looking southwest from adjacent hills on northeast side ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Elevation looking southwest from adjacent hills on northeast side of bridge, taken from river level. Note entire east side and substructure. - Presumpscot Falls Bridge, Spanning Presumptscot River at Allen Avenue extension, 0.75 mile west of U.S. Interstate 95, Falmouth, Cumberland County, ME

  15. 22. Float located adjacent to entry stair in filtration bed. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. Float located adjacent to entry stair in filtration bed. The float actuates a valve that maintains water level over the bed. - Lake Whitney Water Filtration Plant, Filtration Plant, South side of Armory Street between Edgehill Road & Whitney Avenue, Hamden, New Haven County, CT

  16. Gene therapy for retinal degeneration.

    PubMed

    Reichel, M B; Ali, R R; Hunt, D M; Bhattacharya, S S

    1997-01-01

    Inherited retinal degenerations are a group of diseases leading to blindness through progressive loss of vision in many patients. Although with the cloning of more and more disease genes the knowledge on the molecular genetics of these conditions and on the apoptotic pathway as the common disease mechanism is steadily increasing, there is still no cure for those affected. In recent years, new experimental treatments have evolved through the efforts of many investigators and have been explored in animal models. The rationale of the different strategies for developing a treatment based on gene replacement or rescue of the diseased neuronal tissue with growth factors will be outlined and discussed in this paper. PMID:9323717

  17. Regularized degenerate multi-solitons

    NASA Astrophysics Data System (ADS)

    Correa, Francisco; Fring, Andreas

    2016-09-01

    We report complex PT-symmetric multi-soliton solutions to the Korteweg de-Vries equation that asymptotically contain one-soliton solutions, with each of them possessing the same amount of finite real energy. We demonstrate how these solutions originate from degenerate energy solutions of the Schrödinger equation. Technically this is achieved by the application of Darboux-Crum transformations involving Jordan states with suitable regularizing shifts. Alternatively they may be constructed from a limiting process within the context Hirota's direct method or on a nonlinear superposition obtained from multiple Bäcklund transformations. The proposed procedure is completely generic and also applicable to other types of nonlinear integrable systems.

  18. Regularized degenerate multi-solitons

    NASA Astrophysics Data System (ADS)

    Correa, Francisco; Fring, Andreas

    2016-09-01

    We report complex {P}{T} -symmetric multi-soliton solutions to the Korteweg de-Vries equation that asymptotically contain one-soliton solutions, with each of them possessing the same amount of finite real energy. We demonstrate how these solutions originate from degenerate energy solutions of the Schrödinger equation. Technically this is achieved by the application of Darboux-Crum transformations involving Jordan states with suitable regularizing shifts. Alternatively they may be constructed from a limiting process within the context Hirota's direct method or on a nonlinear superposition obtained from multiple Bäcklund transformations. The proposed procedure is completely generic and also applicable to other types of nonlinear integrable systems.

  19. Degenerate doping of metallic anodes

    DOEpatents

    Friesen, Cody A; Zeller, Robert A; Johnson, Paul B; Switzer, Elise E

    2015-05-12

    Embodiments of the invention relate to an electrochemical cell comprising: (i) a fuel electrode comprising a metal fuel, (ii) a positive electrode, (iii) an ionically conductive medium, and (iv) a dopant; the electrodes being operable in a discharge mode wherein the metal fuel is oxidized at the fuel electrode and the dopant increases the conductivity of the metal fuel oxidation product. In an embodiment, the oxidation product comprises an oxide of the metal fuel which is doped degenerately. In an embodiment, the positive electrode is an air electrode that absorbs gaseous oxygen, wherein during discharge mode, oxygen is reduced at the air electrode. Embodiments of the invention also relate to methods of producing an electrode comprising a metal and a doped metal oxidation product.

  20. Photoreceptor Cells Influence Retinal Vascular Degeneration in Mouse Models of Retinal Degeneration and Diabetes

    PubMed Central

    Liu, Haitao; Tang, Jie; Du, Yunpeng; Saadane, Aicha; Tonade, Deoye; Samuels, Ivy; Veenstra, Alex; Palczewski, Krzysztof; Kern, Timothy S.

    2016-01-01

    Purpose Loss of photoreceptor cells is associated with retinal vascular degeneration in retinitis pigmentosa, whereas the presence of photoreceptor cells is implicated in vascular degeneration in diabetic retinopathy. To investigate how both the absence and presence of photoreceptors could damage the retinal vasculature, we compared two mouse models of photoreceptor degeneration (opsin−/− and RhoP23H/P23H ) and control C57Bl/5J mice, each with and without diabetes. Methods Retinal thickness, superoxide, expression of inflammatory proteins, ERG and optokinetic responses, leukocyte cytotoxicity, and capillary degeneration were evaluated at 1 to 10 months of age using published methods. Results Retinal photoreceptor cells degenerated completely in the opsin mutants by 2 to 4 months of age, and visual function subsided correspondingly. Retinal capillary degeneration was substantial while photoreceptors were still present, but slowed after the photoreceptors degenerated. Diabetes did not further exacerbate capillary degeneration in these models of photoreceptor degeneration, but did cause capillary degeneration in wild-type animals. Photoreceptor cells, however, did not degenerate in wild-type diabetic mice, presumably because the stress responses in these cells were less than in the opsin mutants. Retinal superoxide and leukocyte damage to retinal endothelium contributed to the degeneration of retinal capillaries in diabetes, and leukocyte-mediated damage was increased in both opsin mutants during photoreceptor cell degeneration. Conclusions Photoreceptor cells affect the integrity of the retinal microvasculature. Deterioration of retinal capillaries in opsin mutants was appreciable while photoreceptor cells were present and stressed, but was less after photoreceptors degenerated. This finding proves relevant to diabetes, where persistent stress in photoreceptors likewise contributes to capillary degeneration. PMID:27548901

  1. Degenerate adiabatic perturbation theory: Foundations and applications

    NASA Astrophysics Data System (ADS)

    Rigolin, Gustavo; Ortiz, Gerardo

    2014-08-01

    We present details and expand on the framework leading to the recently introduced degenerate adiabatic perturbation theory [Phys. Rev. Lett. 104, 170406 (2010), 10.1103/PhysRevLett.104.170406], and on the formulation of the degenerate adiabatic theorem, along with its necessary and sufficient conditions [given in Phys. Rev. A 85, 062111 (2012), 10.1103/PhysRevA.85.062111]. We start with the adiabatic approximation for degenerate Hamiltonians that paves the way to a clear and rigorous statement of the associated degenerate adiabatic theorem, where the non-Abelian geometric phase (Wilczek-Zee phase) plays a central role to its quantitative formulation. We then describe the degenerate adiabatic perturbation theory, whose zeroth-order term is the degenerate adiabatic approximation, in its full generality. The parameter in the perturbative power-series expansion of the time-dependent wave function is directly associated to the inverse of the time it takes to drive the system from its initial to its final state. With the aid of the degenerate adiabatic perturbation theory we obtain rigorous necessary and sufficient conditions for the validity of the adiabatic theorem of quantum mechanics. Finally, to illustrate the power and wide scope of the methodology, we apply the framework to a degenerate Hamiltonian, whose closed-form time-dependent wave function is derived exactly, and also to other nonexactly solvable Hamiltonians whose solutions are numerically computed.

  2. Inflammatory Mediators in Intervertebral Disk Degeneration and Discogenic Pain

    PubMed Central

    Wuertz, Karin; Haglund, Lisbet

    2013-01-01

    Although degeneration of the intervertebral disk has historically been described as a misbalance between anabolic and catabolic factors, the role of inflammatory mediators has long been neglected. However, past research clearly indicates that inflammatory mediators such as interleukin (IL)-1β, IL-6, IL-8 and tumor necrosis factor-α are expressed at higher levels in “diseased” intervertebral disks. Both disk cells as well as invading macrophages can be the source of the detected cytokines. Importantly, occurrence of inflammatory mediators in the disk can worsen the progress of degeneration by inducing the expression of matrix degrading enzymes as well as by inhibiting extracellular matrix synthesis. In addition, inflammatory mediators play a crucial role in pain development during intervertebral disk herniation (i.e., sciatica) and disk degeneration (i.e., discogenic pain). This review provides information on the most relevant inflammatory mediators during different types of disk diseases and explains how these factors can induce disk degeneration and the development of discogenic and sciatic/radiculopathic pain. PMID:24436868

  3. Degenerated human intervertebral discs contain autoantibodies against extracellular matrix proteins.

    PubMed

    Capossela, S; Schläfli, P; Bertolo, A; Janner, T; Stadler, B M; Pötzel, T; Baur, M; Stoyanov, J V

    2014-04-04

    Degeneration of intervertebral discs (IVDs) is associated with back pain and elevated levels of inflammatory cells. It has been hypothesised that discogenic pain is a direct result of vascular and neural ingrowth along annulus fissures, which may expose the avascular nucleus pulposus (NP) to the systemic circulation and induce an autoimmune reaction. In this study, we confirmed our previous observation of antibodies in human degenerated and post-traumatic IVDs cultured in vitro. We hypothesised that the presence of antibodies was due to an autoimmune reaction against specific proteins of the disc. Furthermore we identified antigens which possibly trigger an autoimmune response in degenerative disc diseases. We demonstrated that degenerated and post-traumatic IVDs contain IgG antibodies against typical extracellular proteins of the disc, particularly proteins of the NP. We identified IgGs against collagen type II and aggrecan, confirming an autoimmune reaction against the normally immune privileged NP. We also found specific IgGs against collagens types I and V, but not against collagen type III. In conclusion, this study confirmed the association between disc degeneration and autoimmunity, and may open the avenue for future studies on developing prognostic, diagnostic and therapy-monitoring markers for degenerative disc diseases.

  4. Suppression of Density Fluctuations in a Quantum Degenerate Fermi Gas

    SciTech Connect

    Sanner, Christian; Su, Edward J.; Keshet, Aviv; Gommers, Ralf; Shin, Yong-il; Huang Wujie; Ketterle, Wolfgang

    2010-07-23

    We study density profiles of an ideal Fermi gas and observe Pauli suppression of density fluctuations (atom shot noise) for cold clouds deep in the quantum degenerate regime. Strong suppression is observed for probe volumes containing more than 10 000 atoms. Measuring the level of suppression provides sensitive thermometry at low temperatures. After this method of sensitive noise measurements has been validated with an ideal Fermi gas, it can now be applied to characterize phase transitions in strongly correlated many-body systems.

  5. Degeneration of biogenic superparamagnetic magnetite.

    PubMed

    Li, Y-L; Pfiffner, S M; Dyar, M D; Vali, H; Konhauser, K; Cole, D R; Rondinone, A J; Phelps, T J

    2009-01-01

    Magnetite crystals precipitated as a consequence of Fe(III) reduction by Shewanella algae BrY after 265 h incubation and 5-year anaerobic storage were investigated with transmission electron microscopy, Mössbauer spectroscopy and X-ray diffraction. The magnetite crystals were typically superparamagnetic with an approximate size of 13 nm. The lattice constants of the 265 h and 5-year crystals are 8.4164A and 8.3774A, respectively. The Mössbauer spectra indicated that the 265 h magnetite had excess Fe(II) in its crystal-chemistry (Fe(3+) (1.990)Fe(2+) (1.015)O(4)) but the 5-year magnetite was Fe(II)-deficient in stoichiometry (Fe(3+) (2.388)Fe(2+) (0.419)O(4)). Such crystal-chemical changes may be indicative of the degeneration of superparamagnetic magnetite through the aqueous oxidization of Fe(II) anaerobically, and the concomitant oxidation of the organic phases (fatty acid methyl esters) that were present during the initial formation of the magnetite. The observation of a corona structure on the aged magnetite corroborates the anaerobic oxidation of Fe(II) on the outer layers of magnetite crystals. These results suggest that there may be a possible link between the enzymatic activity of the bacteria and the stability of Fe(II)-excess magnetite, which may help explain why stable nano-magnetite grains are seldom preserved in natural environments.

  6. Modified gravitational instability of degenerate and non-degenerate dusty plasma

    NASA Astrophysics Data System (ADS)

    Jain, Shweta; Sharma, Prerana

    2016-09-01

    The gravitational instability of strongly coupled dusty plasma (SCDP) is studied considering degenerate and non-degenerate dusty plasma situations. The SCDP system is assumed to be composed of the electrons, ions, neutrals, and strongly coupled dust grains. First, in the high density regime, due to small interparticle distance, the electrons are considered degenerate, whereas the neutrals, dust grains, and ions are treated non-degenerate. In this case, the dynamics of inertialess electrons are managed by Fermi pressure and Bohm potential, while the inertialess ions are by only thermal pressure. Second, in the non-degenerate regime, both the electrons and ions are governed by the thermal pressure. The generalized hydrodynamic model and the normal mode analysis technique are employed to examine the low frequency waves and gravitational instability in both degenerate and non-degenerate cases. The general dispersion relation is discussed for a characteristic timescale which provides two regimes of frequency, i.e., hydrodynamic regime and kinetic regime. Analytical solutions reveal that the collisions reduce the growth rate and have a strong impact on structure formation in both degenerate and non-degenerate circumstances. Numerical estimation on the basis of observed parameters for the degenerate and non-degenerate cases is presented to show the effects of dust-neutral collisions and dust effective velocity in the presence of polarization force. The values of Jeans length and Jeans mass have been estimated for degenerate white dwarfs as Jeans length L J = 1.3 × 10 5 cm and Jeans mass M J = 0.75 × 10 - 3 M⊙ and for non-degenerate laboratory plasma Jeans length L J = 6.86 × 10 16 cm and Jeans mass M J = 0.68 × 10 10 M⊙. The stability of the SCDP system is discussed using the Routh-Hurwitz criterion.

  7. Total absorption by degenerate critical coupling

    SciTech Connect

    Piper, Jessica R. Liu, Victor; Fan, Shanhui

    2014-06-23

    We consider a mirror-symmetric resonator with two ports. We show that, when excited from a single port, complete absorption can be achieved through critical coupling to degenerate resonances with opposite symmetry. Moreover, any time two resonances with opposite symmetry are degenerate in frequency and absorption is always significantly enhanced. In contrast, when two resonances with the same symmetry are nearly degenerate, there is no absorption enhancement. We numerically demonstrate these effects using a graphene monolayer on top of a photonic crystal slab, illuminated from a single side in the near-infrared.

  8. Horizon supertranslation and degenerate black hole solutions

    NASA Astrophysics Data System (ADS)

    Cai, Rong-Gen; Ruan, Shan-Ming; Zhang, Yun-Long

    2016-09-01

    In this note we first review the degenerate vacua arising from the BMS symmetries. According to the discussion in [1] one can define BMS-analogous supertranslation and superrotation for spacetime with black hole in Gaussian null coordinates. In the leading and subleading orders of near horizon approximation, the infinitely degenerate black hole solutions are derived by considering Einstein equations with or without cosmological constant, and they are related to each other by the diffeomorphism generated by horizon supertranslation. Higher order results and degenerate Rindler horizon solutions also are given in appendices.

  9. Advances in the management of macular degeneration

    PubMed Central

    2014-01-01

    Current management of age-related macular degeneration (AMD) can be divided into two categories: first, anti-vasoendothelial growth factor (anti-VEGF) injection for wet macular degeneration; second, anti-oxidant vitamins for dry macular degeneration. New therapies are being developed for both of these diseases using novel technologies and different modes of administration. The hope is that some of these therapies will achieve significant improvement to current management and prevent future loss of vision in this devastating eye condition. PMID:24860651

  10. Neural remodeling in retinal degeneration.

    PubMed

    Marc, Robert E; Jones, Bryan W; Watt, Carl B; Strettoi, Enrica

    2003-09-01

    Mammalian retinal degenerations initiated by gene defects in rods, cones or the retinal pigmented epithelium (RPE) often trigger loss of the sensory retina, effectively leaving the neural retina deafferented. The neural retina responds to this challenge by remodeling, first by subtle changes in neuronal structure and later by large-scale reorganization. Retinal degenerations in the mammalian retina generally progress through three phases. Phase 1 initiates with expression of a primary insult, followed by phase 2 photoreceptor death that ablates the sensory retina via initial photoreceptor stress, phenotype deconstruction, irreversible stress and cell death, including bystander effects or loss of trophic support. The loss of cones heralds phase 3: a protracted period of global remodeling of the remnant neural retina. Remodeling resembles the responses of many CNS assemblies to deafferentation or trauma, and includes neuronal cell death, neuronal and glial migration, elaboration of new neurites and synapses, rewiring of retinal circuits, glial hypertrophy and the evolution of a fibrotic glial seal that isolates the remnant neural retina from the surviving RPE and choroid. In early phase 2, stressed photoreceptors sprout anomalous neurites that often reach the inner plexiform and ganglion cell layers. As death of rods and cones progresses, bipolar and horizontal cells are deafferented and retract most of their dendrites. Horizontal cells develop anomalous axonal processes and dendritic stalks that enter the inner plexiform layer. Dendrite truncation in rod bipolar cells is accompanied by revision of their macromolecular phenotype, including the loss of functioning mGluR6 transduction. After ablation of the sensory retina, Müller cells increase intermediate filament synthesis, forming a dense fibrotic layer in the remnant subretinal space. This layer invests the remnant retina and seals it from access via the choroidal route. Evidence of bipolar cell death begins in

  11. Frontotemporal lobar degeneration: current perspectives

    PubMed Central

    Riedl, Lina; Mackenzie, Ian R; Förstl, Hans; Kurz, Alexander; Diehl-Schmid, Janine

    2014-01-01

    The term frontotemporal lobar degeneration (FTLD) refers to a group of progressive brain diseases, which preferentially involve the frontal and temporal lobes. Depending on the primary site of atrophy, the clinical manifestation is dominated by behavior alterations or impairment of language. The onset of symptoms usually occurs before the age of 60 years, and the mean survival from diagnosis varies between 3 and 10 years. The prevalence is estimated at 15 per 100,000 in the population aged between 45 and 65 years, which is similar to the prevalence of Alzheimer’s disease in this age group. There are two major clinical subtypes, behavioral-variant frontotemporal dementia and primary progressive aphasia. The neuropathology underlying the clinical syndromes is also heterogeneous. A common feature is the accumulation of certain neuronal proteins. Of these, the microtubule-associated protein tau (MAPT), the transactive response DNA-binding protein, and the fused in sarcoma protein are most important. Approximately 10% to 30% of FTLD shows an autosomal dominant pattern of inheritance, with mutations in the genes for MAPT, progranulin (GRN), and in the chromosome 9 open reading frame 72 (C9orf72) accounting for more than 80% of familial cases. Although significant advances have been made in recent years regarding diagnostic criteria, clinical assessment instruments, neuropsychological tests, cerebrospinal fluid biomarkers, and brain imaging techniques, the clinical diagnosis remains a challenge. To date, there is no specific pharmacological treatment for FTLD. Some evidence has been provided for serotonin reuptake inhibitors to reduce behavioral disturbances. No large-scale or high-quality studies have been conducted to determine the efficacy of non-pharmacological treatment approaches in FTLD. In view of the limited treatment options, caregiver education and support is currently the most important component of the clinical management. PMID:24600223

  12. [Cystic degeneration of autonomous adenomas (author's transl)].

    PubMed

    Galvan, G; Pohl, G B

    1976-01-01

    Follow-up examinations in four patients with autonomous adenomas showed cystic degeneration in the autonomous adenomas 20 to 45 months after the first examination, confirmed by fine needle biopsy. Clinical improvement occurred three times with scintigraphic compensation, decompensation occurred once without clinical deterioration. In particular cases a therapeutic policy of wait and see is justified in patients with autonomous adenomas because they may remain clinically inconspicuous for a long time; on the other hand there is a possibility of a cystic degeneration.

  13. Resistive collimation of electron beams in relativistic and degenerate plasma

    NASA Astrophysics Data System (ADS)

    Mahdavi, M.; Khodadadi Azadboni, F.

    2014-09-01

    The purpose of this research is the study of the effects of plasma state and fiber on collimating relativistic electron beam in fast ignition. In this paper, for collimating relativistic electrons produced at the laser plasma interaction, a thin fiber of aluminum, lithium or CH either in the classical, degenerate or relativistic plasma states is considered. The fast electron beam could be collimated down to radii of 10 μm, in that case, the best results are achieved when there is a sharp transition in resistance. This ensures that the correct magnetic growth rate is used for hot electrons at different energy levels. Calculations show that the resistivity of the material surrounding the CH fiber in the degenerate plasma is smaller than that for classical and relativistic plasma.

  14. Imaging of Lesser Metatarsophalangeal Joint Plantar Plate Degeneration, Tear, and Repair.

    PubMed

    Linklater, James M; Bird, Stephen J

    2016-04-01

    Plantar plate degeneration and tear is a common cause of forefoot pain, typically involving the second metatarsophalangeal joint at the proximal phalangeal insertion laterally, frequently confused with the second web space Morton neuroma. The condition has received increased attention with the development of surgical techniques that can result in successful repair of the plantar plate and substantial improvement in patient symptoms. High-resolution MRI or ultrasound can confirm a diagnosis of plantar plate degeneration and tear and exclude other pathologies, particularly Morton neuroma. The normal plantar plate is a mildly hyperechoic structure on ultrasound and is hypointense on all conventional MR sequences. Plantar plate degeneration manifests on ultrasound as hypoechoic echotextural change and on MRI as mild signal hyperintensity on short TE sequences, becoming less conspicuous on long TE sequences. Adjacent entheseal bony irregularity is commonly present. Plantar plate tears on ultrasound may be seen as an anechoic cleft defect or area of heterogeneous echotexture, sometimes more conspicuous with dorsiflexion stress. Plantar plate tears demonstrate greater signal hyperintensity on proton-density sequences, becoming more conspicuous on fat-suppressed proton density and T2-weighted sequences. Edema and fibrotic change in the pericapsular fat plane is commonly seen in the setting of an adjacent plantar plate tear and should not be misinterpreted as reflecting a Morton neuroma.

  15. CERKL Knockdown Causes Retinal Degeneration in Zebrafish

    PubMed Central

    Riera, Marina; Burguera, Demian; Garcia-Fernàndez, Jordi; Gonzàlez-Duarte, Roser

    2013-01-01

    The human CERKL gene is responsible for common and severe forms of retinal dystrophies. Despite intense in vitro studies at the molecular and cellular level and in vivo analyses of the retina of murine knockout models, CERKL function remains unknown. In this study, we aimed to approach the developmental and functional features of cerkl in Danio rerio within an Evo-Devo framework. We show that gene expression increases from early developmental stages until the formation of the retina in the optic cup. Unlike the high mRNA-CERKL isoform multiplicity shown in mammals, the moderate transcriptional complexity in fish facilitates phenotypic studies derived from gene silencing. Moreover, of relevance to pathogenicity, teleost CERKL shares the two main human protein isoforms. Morpholino injection has been used to generate a cerkl knockdown zebrafish model. The morphant phenotype results in abnormal eye development with lamination defects, failure to develop photoreceptor outer segments, increased apoptosis of retinal cells and small eyes. Our data support that zebrafish Cerkl does not interfere with proliferation and neural differentiation during early developmental stages but is relevant for survival and protection of the retinal tissue. Overall, we propose that this zebrafish model is a powerful tool to unveil CERKL contribution to human retinal degeneration. PMID:23671706

  16. On the time-course of adjacent and non-adjacent transposed-letter priming

    PubMed Central

    Ktori, Maria; Kingma, Brechtsje; Hannagan, Thomas; Holcomb, Phillip J.; Grainger, Jonathan

    2014-01-01

    We compared effects of adjacent (e.g., atricle-ARTICLE) and non-adjacent (e.g., actirle-ARTICLE) transposed-letter (TL) primes in an ERP study using the sandwich priming technique. TL priming was measured relative to the standard double-substitution condition. We found significantly stronger priming effects for adjacent transpositions than non-adjacent transpositions (with 2 intervening letters) in behavioral responses (lexical decision latencies), and the adjacent priming effects emerged earlier in the ERP signal, at around 200 ms post-target onset. Non-adjacent priming effects emerged about 50 ms later and were short-lived, being significant only in the 250-300 ms time-window. Adjacent transpositions on the other hand continued to produce priming in the N400 time-window (300-500 ms post-target onset). This qualitatively different pattern of priming effects for adjacent and non-adjacent transpositions is discussed in the light of different accounts of letter transposition effects, and the utility of drawing a distinction between positional flexibility and positional noise. PMID:25364497

  17. Müller cell metabolic chaos during retinal degeneration.

    PubMed

    Pfeiffer, Rebecca L; Marc, Robert E; Kondo, Mineo; Terasaki, Hiroko; Jones, Bryan W

    2016-09-01

    Müller cells play a critical role in retinal metabolism and are among the first cells to demonstrate metabolic changes in retinal stress or disease. The timing, extent, regulation, and impacts of these changes are not yet known. We evaluated metabolic phenotypes of Müller cells in the degenerating retina. Retinas harvested from wild-type (WT) and rhodopsin Tg P347L rabbits were fixed in mixed aldehydes and resin embedded for computational molecular phenotyping (CMP). CMP facilitates small molecule fingerprinting of every cell in the retina, allowing evaluation of metabolite levels in single cells. CMP revealed signature variations in metabolite levels across Müller cells from TgP347L retina. In brief, neighboring Müller cells demonstrated variability in taurine, glutamate, glutamine, glutathione, glutamine synthetase (GS), and CRALBP. This variability showed no correlation across metabolites, implying the changes are functionally chaotic rather than simply heterogeneous. The inability of any clustering algorithm to classify Müller cell as a single class in the TgP347L retina is a formal proof of metabolic variability in the present in degenerating retina. Although retinal degeneration is certainly the trigger, Müller cell metabolic alterations are not a coherent response to the microenvironment. And while GS is believed to be the primary enzyme responsible for the conversion of glutamate to glutamine in the retina, alternative pathways appear to be unmasked in degenerating retina. Somehow, long term remodeling involves loss of Müller cell coordination and identity, which has negative implications for therapeutic interventions that target neurons alone. PMID:27142256

  18. Altered Knee Joint Mechanics in Simple Compression Associated with Early Cartilage Degeneration

    PubMed Central

    Dabiri, Y.; Li, L. P.

    2013-01-01

    The progression of osteoarthritis can be accompanied by depth-dependent changes in the properties of articular cartilage. The objective of the present study was to determine the subsequent alteration in the fluid pressurization in the human knee using a three-dimensional computer model. Only a small compression in the femur-tibia direction was applied to avoid numerical difficulties. The material model for articular cartilages and menisci included fluid, fibrillar and nonfibrillar matrices as distinct constituents. The knee model consisted of distal femur, femoral cartilage, menisci, tibial cartilage, and proximal tibia. Cartilage degeneration was modeled in the high load-bearing region of the medial condyle of the femur with reduced fibrillar and nonfibrillar elastic properties and increased hydraulic permeability. Three case studies were implemented to simulate (1) the onset of cartilage degeneration from the superficial zone, (2) the progression of cartilage degeneration to the middle zone, and (3) the progression of cartilage degeneration to the deep zone. As compared with a normal knee of the same compression, reduced fluid pressurization was observed in the degenerated knee. Furthermore, faster reduction in fluid pressure was observed with the onset of cartilage degeneration in the superficial zone and progression to the middle zone, as compared to progression to the deep zone. On the other hand, cartilage degeneration in any zone would reduce the fluid pressure in all three zones. The shear strains at the cartilage-bone interface were increased when cartilage degeneration was eventually advanced to the deep zone. The present study revealed, at the joint level, altered fluid pressurization and strains with the depth-wise cartilage degeneration. The results also indicated redistribution of stresses within the tissue and relocation of the loading between the tissue matrix and fluid pressure. These results may only be qualitatively interesting due to the small

  19. The Retromer Complex Is Required for Rhodopsin Recycling and Its Loss Leads to Photoreceptor Degeneration

    PubMed Central

    Wang, Shiuan; Tan, Kai Li; Agosto, Melina A.; Xiong, Bo; Yamamoto, Shinya; Sandoval, Hector; Jaiswal, Manish; Bayat, Vafa; Zhang, Ke; Charng, Wu-Lin; David, Gabriela; Duraine, Lita; Venkatachalam, Kartik; Wensel, Theodore G.; Bellen, Hugo J.

    2014-01-01

    Rhodopsin mistrafficking can cause photoreceptor (PR) degeneration. Upon light exposure, activated rhodopsin 1 (Rh1) in Drosophila PRs is internalized via endocytosis and degraded in lysosomes. Whether internalized Rh1 can be recycled is unknown. Here, we show that the retromer complex is expressed in PRs where it is required for recycling endocytosed Rh1 upon light stimulation. In the absence of subunits of the retromer, Rh1 is processed in the endolysosomal pathway, leading to a dramatic increase in late endosomes, lysosomes, and light-dependent PR degeneration. Reducing Rh1 endocytosis or Rh1 levels in retromer mutants alleviates PR degeneration. In addition, increasing retromer abundance suppresses degenerative phenotypes of mutations that affect the endolysosomal system. Finally, expressing human Vps26 suppresses PR degeneration in Vps26 mutant PRs. We propose that the retromer plays a conserved role in recycling rhodopsins to maintain PR function and integrity. PMID:24781186

  20. Optic pathway degeneration in Japanese black cattle.

    PubMed

    Chiba, Shiori; Funato, Shingo; Horiuchi, Noriyuki; Matsumoto, Kotaro; Inokuma, Hisashi; Furuoka, Hidefumi; Kobayashi, Yoshiyasu

    2015-02-01

    Degeneration of the optic pathway has been reported in various animal species including cattle. We experienced a case of bilateral optic tract degeneration characterized by severe gliosis in a Japanese black cattle without any obvious visual defects. To evaluate the significance, pathological nature and pathogenesis of the lesions, we examined the optic pathway in 60 cattle (41 Japanese black, 13 Holstein and 6 crossbreed) with or without ocular abnormalities. None of these animals had optic canal stenosis. Degenerative changes with severe gliosis in the optic pathway, which includes the optic nerve, optic chiasm and optic tract, were only observed in 8 Japanese black cattle with or without ocular abnormalities. Furthermore, strong immunoreactivity of glial fibrillary acidic protein was observed in the retinal stratum opticum and ganglion cell layer in all 5 cattle in which the optic pathway lesions could be examined. As etiological research, we also examined whether the concentrations of vitamin A and vitamin B12 or bovine viral diarrhea virus (BVDV) infection was associated with optic pathway degeneration. However, our results suggested that the observed optic pathway degeneration was probably not caused by these factors. These facts indicate the presence of optic pathway degeneration characterized by severe gliosis that has never been reported in cattle without bilateral compressive lesions in the optic pathway or bilateral severe retinal atrophy. PMID:25421501

  1. Optic pathway degeneration in Japanese black cattle.

    PubMed

    Chiba, Shiori; Funato, Shingo; Horiuchi, Noriyuki; Matsumoto, Kotaro; Inokuma, Hisashi; Furuoka, Hidefumi; Kobayashi, Yoshiyasu

    2015-02-01

    Degeneration of the optic pathway has been reported in various animal species including cattle. We experienced a case of bilateral optic tract degeneration characterized by severe gliosis in a Japanese black cattle without any obvious visual defects. To evaluate the significance, pathological nature and pathogenesis of the lesions, we examined the optic pathway in 60 cattle (41 Japanese black, 13 Holstein and 6 crossbreed) with or without ocular abnormalities. None of these animals had optic canal stenosis. Degenerative changes with severe gliosis in the optic pathway, which includes the optic nerve, optic chiasm and optic tract, were only observed in 8 Japanese black cattle with or without ocular abnormalities. Furthermore, strong immunoreactivity of glial fibrillary acidic protein was observed in the retinal stratum opticum and ganglion cell layer in all 5 cattle in which the optic pathway lesions could be examined. As etiological research, we also examined whether the concentrations of vitamin A and vitamin B12 or bovine viral diarrhea virus (BVDV) infection was associated with optic pathway degeneration. However, our results suggested that the observed optic pathway degeneration was probably not caused by these factors. These facts indicate the presence of optic pathway degeneration characterized by severe gliosis that has never been reported in cattle without bilateral compressive lesions in the optic pathway or bilateral severe retinal atrophy.

  2. MINARETS WILDERNESS AND ADJACENT AREAS, CALIFORNIA.

    USGS Publications Warehouse

    Huber, N. King; Thurber, Horace K.

    1984-01-01

    A mineral survey of the Minarets Wilderness and adjacent areas in the central Sierra Nevada, California was conducted. The results of the survey indicate that the study area has a substantiated resource potential for small deposits of copper, silver, zinc, lead, and iron, and a probable mineral-resource potential for molybdenum. No energy-resource potential was identified in the study.

  3. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS... transporting a material that Table 148.10 of this part associates with a reference to this section, the following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  4. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS... transporting a material that Table 148.10 of this part associates with a reference to this section, the following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  5. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS... transporting a material that Table 148.10 of this part associates with a reference to this section, the following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  6. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS... transporting a material that Table 148.10 of this part associates with a reference to this section, the following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  7. Adjacent channel interference degradation with minimum shift keyed modulation

    NASA Technical Reports Server (NTRS)

    Ziemer, R. E.

    1981-01-01

    Computer simulation results for degradation in signal-to-noise ratio for various values of bit error probability are given for minimum shift-keyed-type signaling in the presence of adjacent channel interference. A serial modulator structure which utilizes spectral shaping is characterized in terms of envelope deviation and bandwidth efficiency. This serial generation technique is convenient for implementation at high data rates and results in signal spectra with lower sidelobe levels than conventional minimum shift-keyed modulation at the expense of moderate envelope deviation. Because of the lower sidelobe levels, the resulting spectra allow denser channel packing than does ideal MSK.

  8. The cell stress machinery and retinal degeneration.

    PubMed

    Athanasiou, Dimitra; Aguilà, Monica; Bevilacqua, Dalila; Novoselov, Sergey S; Parfitt, David A; Cheetham, Michael E

    2013-06-27

    Retinal degenerations are a group of clinically and genetically heterogeneous disorders characterised by progressive loss of vision due to neurodegeneration. The retina is a highly specialised tissue with a unique architecture and maintaining homeostasis in all the different retinal cell types is crucial for healthy vision. The retina can be exposed to a variety of environmental insults and stress, including light-induced damage, oxidative stress and inherited mutations that can lead to protein misfolding. Within retinal cells there are different mechanisms to cope with disturbances in proteostasis, such as the heat shock response, the unfolded protein response and autophagy. In this review, we discuss the multiple responses of the retina to different types of stress involved in retinal degenerations, such as retinitis pigmentosa, age-related macular degeneration and glaucoma. Understanding the mechanisms that maintain and re-establish proteostasis in the retina is important for developing new therapeutic approaches to fight blindness. PMID:23684651

  9. Potential Outcome Factors in Subacute Combined Degeneration

    PubMed Central

    Vasconcelos, Olavo M; Poehm, Erika H; McCarter, Robert J; Campbell, William W; Quezado, Zenaide M N

    2006-01-01

    BACKGROUND Subacute combined degeneration is an acquired myelopathy caused by vitamin B12 deficiency. Therapy with B12 leads to improvement in most but to complete recovery in only a few patients. Prognostic indicators in subacute combined degeneration are unknown; therefore, predicting complete recovery of neurologic deficits is challenging. PURPOSE To identify potential correlates of outcome and to generate hypotheses concerning predictors of complete resolution of neurologic deficits in subacute combined degeneration. DATA SOURCE We searched EMBASE (1974 to October 2005), MEDLINE (1968 to October 2005), and references from identified reports. REPORTS SELECTION Reports of patients with subacute combined degeneration containing results of magnetic resonance imaging (MRI) and description of outcome and 1 patient treated by the authors. DATA EXTRACTION, SYNTHESIS We extracted data from 45 reports and 57 patients (36 males, 21 females; age range: 10 to 81) with a diagnosis of subacute combined degeneration, and estimated the strength of association between clinical, laboratory, and radiological factors and complete resolution of signs and symptoms. RESULTS Eight patients (14%) achieved clinical resolution and 49 (86%) improved with B12 therapy. The absence of sensory dermatomal deficit, Romberg, and Babinski signs were associated with a higher complete resolution rate. Patients with MRI lesions in ≤7 segments and age less than 50 also appear to have higher rates of complete resolution. CONCLUSIONS B12 therapy is reported to stop progression and improve neurologic deficits in most patients with subacute combined degeneration. However, complete resolution only occurs in a small percentage of patients and appears to be associated with factors suggestive of less severe disease at the time of diagnosis. PMID:16970556

  10. Phase diagram of degenerate exciton systems.

    PubMed

    Lai, C W; Zoch, J; Gossard, A C; Chemla, D S

    2004-01-23

    Degenerate exciton systems have been produced in quasi-two-dimensional confined areas in semiconductor coupled quantum well structures. We observed contractions of clouds containing tens of thousands of excitons within areas as small as (10 micron)2 near 10 kelvin. The spatial and energy distributions of optically active excitons were determined by measuring photoluminescence as a function of temperature and laser excitation and were used as thermodynamic quantities to construct the phase diagram of the exciton system, which demonstrates the existence of distinct phases. Understanding the formation mechanisms of these degenerate exciton systems can open new opportunities for the realization of Bose-Einstein condensation in the solid state.

  11. Pathogenesis of tendinopathies: inflammation or degeneration?

    PubMed Central

    Abate, Michele; Gravare-Silbernagel, Karin; Siljeholm, Carl; Di Iorio, Angelo; De Amicis, Daniele; Salini, Vincenzo; Werner, Suzanne; Paganelli, Roberto

    2009-01-01

    The intrinsic pathogenetic mechanisms of tendinopathies are largely unknown and whether inflammation or degeneration has the prominent role is still a matter of debate. Assuming that there is a continuum from physiology to pathology, overuse may be considered as the initial disease factor; in this context, microruptures of tendon fibers occur and several molecules are expressed, some of which promote the healing process, while others, including inflammatory cytokines, act as disease mediators. Neural in-growth that accompanies the neovessels explains the occurrence of pain and triggers neurogenic-mediated inflammation. It is conceivable that inflammation and degeneration are not mutually exclusive, but work together in the pathogenesis of tendinopathies. PMID:19591655

  12. Retinal Cell Degeneration in Animal Models

    PubMed Central

    Niwa, Masayuki; Aoki, Hitomi; Hirata, Akihiro; Tomita, Hiroyuki; Green, Paul G.; Hara, Akira

    2016-01-01

    The aim of this review is to provide an overview of various retinal cell degeneration models in animal induced by chemicals (N-methyl-d-aspartate- and CoCl2-induced), autoimmune (experimental autoimmune encephalomyelitis), mechanical stress (optic nerve crush-induced, light-induced) and ischemia (transient retinal ischemia-induced). The target regions, pathology and proposed mechanism of each model are described in a comparative fashion. Animal models of retinal cell degeneration provide insight into the underlying mechanisms of the disease, and will facilitate the development of novel effective therapeutic drugs to treat retinal cell damage. PMID:26784179

  13. [Degenerated papillomatosis of the bile duct].

    PubMed

    De Castro Gutiérrez, J; Armengol Carrasco, M; Oller Sales, B; Fdez-Llamazares Rodríguez, J; Julián Ibáñez, J F; Broggi Trías, M A; Salvá Lacombe, J A

    1989-07-01

    Papillomatosis of the biliary ducts is exceptional. It is defined by the presence of multiple, benign, papillary type, epithelial tumors on the choledochus and hepatic ducts, and can also effect the gallbladder and intrahepatic bile ducts. It courses with a tendency to recurrence and secondary degeneration, and its prognosis is uncertain and sometimes grave. The treatment is surgical and depends on the extension of the lesions, often being only palliative. The techniques of choice are curettage and biliodigestive derivation. A case is presented of degenerated papillomatosis treated by cephalic duodenopancreatectomy and cholecystectomy.

  14. Frontotemporal Lobar Degeneration and MicroRNAs

    PubMed Central

    Piscopo, Paola; Albani, Diego; Castellano, Anna E.; Forloni, Gianluigi; Confaloni, Annamaria

    2016-01-01

    Frontotemporal lobar degeneration (FTLD) includes a spectrum of disorders characterized by changes of personality and social behavior and, often, a gradual and progressive language dysfunction. In the last years, several efforts have been fulfilled in identifying both genetic mutations and pathological proteins associated with FTLD. The molecular bases undergoing the onset and progression of the disease remain still unknown. Recent literature prompts an involvement of RNA metabolism in FTLD, particularly microRNAs (miRNAs). Dysregulation of miRNAs in several disorders, including neurodegenerative diseases, and increasing importance of circulating miRNAs in different pathologies has suggested to implement the study of their possible application as biological markers and new therapeutic targets; moreover, miRNA-based therapy is becoming a powerful tool to deepen the function of a gene, the mechanism of a disease, and validate therapeutic targets. Regarding FTLD, different studies showed that miRNAs are playing an important role. For example, several reports have evaluated miRNA regulation of the progranulin gene suggesting that it is under their control, as described for miR-29b, miR-107, and miR-659. More recently, it has been demonstrated that TMEM106B gene, which protein is elevated in FTLD-TDP brains, is repressed by miR-132/212 cluster; this post-transcriptional mechanism increases intracellular levels of progranulin, affecting its pathways. These findings if confirmed could suggest that these microRNAs have a role as potential targets for some related-FTLD genes. In this review, we focus on the emerging roles of the miRNAs in the pathogenesis of FTLD. PMID:26903860

  15. Topological order-by-disorder in orbitally degenerate dipolar bosons on a zigzag lattice

    NASA Astrophysics Data System (ADS)

    Sun, G.; Vekua, T.

    2014-09-01

    Spinor bosons offer a conceptually simple picture of macroscopic quantum behavior of topological order-by-disorder: The paramagnetic state of two-component dipolar bosons in an orbitally degenerate zigzag lattice is unstable against infinitesimal quantum fluctuations of orbitals, λ, towards developing nonlocal hidden order. Adjacent to the topological state a locally correlated exact ground state with spontaneously a quadrupoled lattice constant is realized for the broad parameter regime. The topological order is extremely robust surviving the λ →∞ limit where the ground state evolves into the Majumdar-Ghosh state of a frustrated spin-1/2 chain.

  16. Sodium and Potassium Currents Influence Wallerian Degeneration of Injured Drosophila Axons

    PubMed Central

    Mishra, Bibhudatta; Carson, Ross; Hume, Richard I.

    2013-01-01

    Axons degenerate after injury and in neuropathies and disease via a self-destruction program whose mechanism is poorly understood. Axons that have lost connection to their cell bodies have altered electrical and synaptic activities, but whether such changes play a role in the axonal degeneration process is not clear. We have used a Drosophila model to study the Wallerian degeneration of motoneuron axons and their neuromuscular junction synapses. We found that degeneration of the distal nerve stump after a nerve crush is greatly delayed when there is increased potassium channel activity (by overexpression of two different potassium channels, Kir2.1 and dORKΔ-C) or decreased voltage-gated sodium channel activity (using mutations in the para sodium channel). Conversely, degeneration is accelerated when potassium channel activity is decreased (by expressing a dominant-negative mutation of Shaker). Despite the effect of altering voltage-gated sodium and potassium channel activity, recordings made after nerve crush demonstrated that the distal stump does not fire action potentials. Rather, a variety of lines of evidence suggest that the sodium and potassium channels manifest their effects upon degeneration through changes in the resting membrane potential, which in turn regulates the level of intracellular free calcium within the isolated distal axon. PMID:24285879

  17. The Involvement of Protease Nexin-1 (PN1) in the Pathogenesis of Intervertebral Disc (IVD) Degeneration

    PubMed Central

    Wu, Xinghuo; Liu, Wei; Duan, Zhenfeng; Gao, Yong; Li, Shuai; Wang, Kun; Song, Yu; Shao, Zengwu; Yang, Shuhua; Yang, Cao

    2016-01-01

    Protease nexin-1 (PN-1) is a serine protease inhibitor belonging to the serpin superfamily. This study was undertaken to investigate the regulatory role of PN-1 in the pathogenesis of intervertebral disk (IVD) degeneration. Expression of PN-1 was detected in human IVD tissue of varying grades. Expression of both PN-1 mRNA and protein was significantly decreased in degenerated IVD, and the expression levels of PN-1 were correlated with the grade of disc degeneration. Moreover, a decrease in PN-1 expression in primary NP cells was confirmed. On induction by IL-1β, the expression of PN-1 in NP cells was decreased at day 7, 14, and 21, as shown by western blot analysis and immunofluorescence staining. PN-1 administration decreased IL-1β-induced MMPs and ADAMTS production and the loss of Agg and Col II in NP cell cultures through the ERK1/2/NF-kB signaling pathway. The changes in PN-1 expression are involved in the pathogenesis of IVD degeneration. Our findings indicate that PN-1 administration could antagonize IL-1β-induced MMPs and ADAMTS, potentially preventing degeneration of IVD tissue. This study also revealed new insights into the regulation of PN-1 expression via the ERK1/2/NF-kB signaling pathway and the role of PN-1 in the pathogenesis of IVD degeneration. PMID:27460424

  18. Experimental model of intervertebral disc degeneration by needle puncture in Wistar rats

    PubMed Central

    Issy, A.C.; Castania, V.; Castania, M.; Salmon, C.E.G.; Nogueira-Barbosa, M.H.; Bel, E. Del; Defino, H.L.A.

    2013-01-01

    Animal models of intervertebral disc degeneration play an important role in clarifying the physiopathological mechanisms and testing novel therapeutic strategies. The objective of the present study is to describe a simple animal model of disc degeneration involving Wistar rats to be used for research studies. Disc degeneration was confirmed and classified by radiography, magnetic resonance and histological evaluation. Adult male Wistar rats were anesthetized and submitted to percutaneous disc puncture with a 20-gauge needle on levels 6-7 and 8-9 of the coccygeal vertebrae. The needle was inserted into the discs guided by fluoroscopy and its tip was positioned crossing the nucleus pulposus up to the contralateral annulus fibrosus, rotated 360° twice, and held for 30 s. To grade the severity of intervertebral disc degeneration, we measured the intervertebral disc height from radiographic images 7 and 30 days after the injury, and the signal intensity T2-weighted magnetic resonance imaging. Histological analysis was performed with hematoxylin-eosin and collagen fiber orientation using picrosirius red staining and polarized light microscopy. Imaging and histological score analyses revealed significant disc degeneration both 7 and 30 days after the lesion, without deaths or systemic complications. Interobserver histological evaluation showed significant agreement. There was a significant positive correlation between histological score and intervertebral disc height 7 and 30 days after the lesion. We conclude that the tail disc puncture method using Wistar rats is a simple, cost-effective and reproducible model for inducing disc degeneration. PMID:23532265

  19. Adjacent Segment Pathology after Lumbar Spinal Fusion.

    PubMed

    Lee, Jae Chul; Choi, Sung-Woo

    2015-10-01

    One of the major clinical issues encountered after lumbar spinal fusion is the development of adjacent segment pathology (ASP) caused by increased mechanical stress at adjacent segments, and resulting in various radiographic changes and clinical symptoms. This condition may require surgical intervention. The incidence of ASP varies with both the definition and methodology adopted in individual studies; various risk factors for this condition have been identified, although a significant controversy still exists regarding their significance. Motion-preserving devices have been developed, and some studies have shown their efficacy of preventing ASP. Surgeons should be aware of the risk factors of ASP when planning a surgery, and accordingly counsel their patients preoperatively. PMID:26435804

  20. Adjacent Segment Pathology after Lumbar Spinal Fusion

    PubMed Central

    Lee, Jae Chul

    2015-01-01

    One of the major clinical issues encountered after lumbar spinal fusion is the development of adjacent segment pathology (ASP) caused by increased mechanical stress at adjacent segments, and resulting in various radiographic changes and clinical symptoms. This condition may require surgical intervention. The incidence of ASP varies with both the definition and methodology adopted in individual studies; various risk factors for this condition have been identified, although a significant controversy still exists regarding their significance. Motion-preserving devices have been developed, and some studies have shown their efficacy of preventing ASP. Surgeons should be aware of the risk factors of ASP when planning a surgery, and accordingly counsel their patients preoperatively. PMID:26435804

  1. Transient forebrain ischemia-induced neuronal degeneration in fascia dentata transplants.

    PubMed

    Tønder, N; Aznar, S; Johansen, F F

    1994-01-01

    Fascia dentata tissue blocks from newborn rats were grafted into one-week-old, ibotenic acid-induced lesions of the fascia dentata, or the normal fascia dentata of adult rats. After at least 2 months survival the recipient rats were subjected to 10 min of forebrain ischemia (4-vessel occlusion), and examined 2 or 4 days later for neuronal degeneration in the host hippocampi and the transplants, by silver staining and immunohistochemistry. Transplants survived well in both normal and lesioned host brains, with easily recognizable subfields and layers and presence of normal types of principal and non-principal neurons. As expected, argyrophilic, degenerating neurons were present in the pyramidal cell layer of CAl and CA3c of the non-grafted contralateral host hippocampus and in the contralateral dentate hilus (CA4). In the hilus the degeneration corresponded to the loss of somatostatin-immunoreactive neurons, while parvalbumin-immunoreactive neurons were spared. In the dentate transplants degenerating neurons were observed in the granule cell layer, the hilus and the adjacent CA3 pyramidal cell layer. There was no obvious loss of either somatostatin- or parvalbumin-immunoreactive neurons. The degeneration varied considerably between transplants, from a few to large groups of silver stained neurons, but this difference did not display any obvious relation to grafting into normal or lesioned hosts, the exact location of the grafts or the general organization and distribution of intrinsic or extrinsic host afferents in the grafts. The results demonstrate that both ischemia-susceptible and -resistant types of neurons grafted to normal and lesioned adult rat brains are susceptible to transient forebrain ischemia after transplantation. In spite of an extensive reorganization of transplant nerve connections, the physiologicalbiochemical mechanisms necessary for the induction of ischemic cell death were accordingly present in the transplants.

  2. Suppression of density fluctuations in a quantum degenerate Fermi gas.

    PubMed

    Sanner, Christian; Su, Edward J; Keshet, Aviv; Gommers, Ralf; Shin, Yong-Il; Huang, Wujie; Ketterle, Wolfgang

    2010-07-23

    We study density profiles of an ideal Fermi gas and observe Pauli suppression of density fluctuations (atom shot noise) for cold clouds deep in the quantum degenerate regime. Strong suppression is observed for probe volumes containing more than 10 000 atoms. Measuring the level of suppression provides sensitive thermometry at low temperatures. After this method of sensitive noise measurements has been validated with an ideal Fermi gas, it can now be applied to characterize phase transitions in strongly correlated many-body systems.

  3. Two-photon interferences with degenerate and nondegenerate paired photons

    NASA Astrophysics Data System (ADS)

    Liu, Chang; Chen, J. F.; Zhang, Shanchao; Zhou, Shuyu; Kim, Yoon-Ho; Loy, M. M. T.; Wong, G. K. L.; Du, Shengwang

    2012-02-01

    We generate narrow-band frequency-tunable entangled photon pairs from spontaneous four-wave mixing in three-level cold atoms and study their two-photon quantum interference after a beam splitter. We find that the path-exchange symmetry plays a more important role in the Hong-Ou-Mandel interference than the temporal or frequency indistinguishability, and observe coalescence interference for both degenerate and nondegenerate photons. We also observe a quantum beat in the same experimental setup using either slow or fast detectors.

  4. Squalamine lactate for exudative age-related macular degeneration.

    PubMed

    Connolly, Brian; Desai, Avinash; Garcia, Charles A; Thomas, Edgar; Gast, Michael J

    2006-09-01

    Squalamine lactate inhibits angiogenesis by a long-lived, intracellular mechanism of action. The drug is taken up into activated endothelial cells through caveolae, small invaginations in the cellular membrane. Subsequently, the drug binds to and "chaperones" calmodulin to an intracellular membrane compartment and blocks angiogenesis at several levels. A series of basic investigations, preclinical studies, and human clinical trials have begun to establish the proof of concept, efficacy, and safety parameters for use of squalamine lactate as a therapeutic agent for exudative age-related macular degeneration and several types of malignancies. PMID:16935213

  5. Depression in Age-Related Macular Degeneration

    ERIC Educational Resources Information Center

    Casten, Robin; Rovner, Barry

    2008-01-01

    Age-related macular degeneration (AMD) is a major cause of disability in the elderly, substantially degrades the quality of their lives, and is a risk factor for depression. Rates of depression in AMD are substantially greater than those found in the general population of older people, and are on par with those of other chronic and disabling…

  6. Driving and Age-Related Macular Degeneration

    ERIC Educational Resources Information Center

    Owsley, Cynthia; McGwin, Gerald, Jr.

    2008-01-01

    This article reviews the research literature on driving and age-related macular degeneration, which is motivated by the link between driving and the quality of life of older adults and their increased collision rate. It addresses the risk of crashes, driving performance, driving difficulty, self-regulation, and interventions to enhance, safety,…

  7. The nature of apraxia in corticobasal degeneration.

    PubMed Central

    Leiguarda, R; Lees, A J; Merello, M; Starkstein, S; Marsden, C D

    1994-01-01

    Although apraxia is one of the most frequent signs in corticobasal degeneration, the phenomenology of this disorder has not been formally examined. Hence 10 patients with corticobasal degeneration were studied with a standardised evaluation for different types of apraxia. To minimise the confounding effects of the primary motor disorder, apraxia was assessed in the least affected limb. Whereas none of the patients showed buccofacial apraxia, seven showed deficits on tests of ideomotor apraxia and movement imitation, four on tests of sequential arm movements (all of whom had ideomotor apraxia), and three on tests of ideational apraxia (all of whom had ideomotor apraxia). Ideomotor apraxia significantly correlated with deficit in both the mini mental state examination and in a task sensitive to frontal lobe dysfunction (picture arrangement). Two of the three patients with ideomotor apraxia and ideational apraxia showed severe cognitive impairments. The alien limb behaviour was present only in patients with ideomotor apraxia. In conclusion, ideomotor apraxia is the most frequent type of apraxia in corticobasal degeneration, and may be due to dysfunction of the supplementary motor area. There is a subgroup of patients with corticobasal degeneration who have a severe apraxia (ideomotor and ideational apraxia), which correlates with global cognitive impairment, and may result from additional parietal or diffuse cortical damage. PMID:8163995

  8. On abstract degenerate neutral differential equations

    NASA Astrophysics Data System (ADS)

    Hernández, Eduardo; O'Regan, Donal

    2016-10-01

    We introduce a new abstract model of functional differential equations, which we call abstract degenerate neutral differential equations, and we study the existence of strict solutions. The class of problems and the technical approach introduced in this paper allow us to generalize and extend recent results on abstract neutral differential equations. Some examples on nonlinear partial neutral differential equations are presented.

  9. Spectroscopic observations of cool degenerate star candidates

    NASA Technical Reports Server (NTRS)

    Hintzen, P.

    1986-01-01

    Spectroscopic observations are reported for 23 Luyten Half-Second degenerate star candidates and for 13 Luyten-Palomar common proper-motion pairs containing possible degenerate star components. Twenty-five degenerate stars are identified, 20 of which lack previous spectroscopy. Most of these stars are cool - Luyten color class g or later. One star, LP 77-57, shows broad continuum depressions similar to those in LHS 1126, which Liebert and Dahn attributed to pressure-shifted C2. A second degenerate star, LHS 290, exhibits apparent strong Swan bands which are blueshifted about 75 A. Further observations, including polarimetry and photometry, are required to appraise the spectroscopic peculiarities of these stars. Finally, five cool, sharp-lined DA white dwarfs have been observed to detect lines of metals and to determine line strengths. None of these DAs show signs of Mg b or the G band, and four show no evidence of Ca II K. The attempt to detect Ca MI in the fifth star, G199-71, was inconclusive.

  10. Lack of Acid Sphingomyelinase Induces Age-Related Retinal Degeneration

    PubMed Central

    Wu, Bill X.; Fan, Jie; Boyer, Nicholas P.; Jenkins, Russell W.; Koutalos, Yiannis; Hannun, Yusuf A.; Crosson, Craig E.

    2015-01-01

    Background Mutations of acid sphingomyelinase (ASMase) cause Niemann–Pick diseases type A and B, which are fatal inherited lipid lysosomal storage diseases, characterized with visceral organ abnormalities and neurodegeneration. However, the effects of suppressing retinal ASMase expression are not understood. The goal of this study was to determine if the disruption of ASMase expression impacts the retinal structure and function in the mouse, and begin to investigate the mechanisms underlying these abnormalities. Methods Acid sphingomyelinase knockout (ASMase KO) mice were utilized to study the roles of this sphingolipid metabolizing enzyme in the retina. Electroretinogram and morphometric analysis were used to assess the retinal function and structure at various ages. Sphingolipid profile was determined by liquid chromatography-mass spectrometry. Western blots evaluated the level of the autophagy marker LC3-II. Results When compared to control animals, ASMase KO mice exhibited significant age-dependent reduction in ERG a- and b-wave amplitudes. Associated with these functional deficits, morphometric analysis revealed progressive thinning of retinal layers; however, the most prominent degeneration was observed in the photoreceptor and outer nuclear layer. Additional analyses of ASMase KO mice revealed early reduction in ERG c-wave amplitudes and increased lipofuscin accumulation in the retinal pigment epithelium (RPE). Sphingolipid analyses showed abnormal accumulation of sphingomyelin and sphingosine in ASMase KO retinas. Western blot analyses showed a higher level of the autophagosome marker LC3-II. Conclusions These studies demonstrate that ASMase is necessary for the maintenance of normal retinal structure and function. The early outer retinal dysfunction, outer segment degeneration, accumulation of lipofuscin and autophagosome markers provide evidence that disruption of lysosomal function contributes to the age-dependent retinal degeneration exhibited by

  11. Pseudotumoral encapsulated fat necrosis with diffuse pseudomembranous degeneration.

    PubMed

    Felipo, F; Vaquero, M; del Agua, C

    2004-09-01

    An extraordinary case of encapsulated fat necrosis characterized by its large size, diffuse formation of pseudomembranes, and tendency to recur after excision is reported. A 67-year-old Caucasian woman suffering from morbid obesity was admitted for diagnosis and surgical treatment of a soft tissue mass showing a longest diameter of 14 cm and lying adjacently to the scar from previous appendicectomy. Histopathologic features were consistent with a nodular-cystic encapsulated fat necrosis with diffuse pseudomembranous transformation. Eight months after surgery, a new larger mass (longest diameter of 18 cm) sharing identical histopathologic features appeared in the same location. Encapsulated fat necrosis is a well-defined entity even though several names have been proposed for this condition, including mobile encapsulated lipoma, encapsulated necrosis, or nodular-cystic fat necrosis. Its pathogenesis seems to be related to ischemic changes secondary to previous trauma. It may occasionally show degenerative changes, including dystrophic calcifications and presence of pseudomembranes. To our knowledge, these are the first reported cases of encapsulated fat necrosis presenting as lesions of such size and showing diffuse formation of pseudomembranes; these particular features made diagnosis difficult and led to consideration of a wide range of potential diagnostic possibilities. This case expands the clinico-pathologic spectrum of membranocystic fat necrosis, including the potential ability of this subcutaneous fatty tissue abnormality to recur after surgical excision. Felipo F, Vaquero M, del Agua C. Pseudotumoral encapsulated fat necrosis with diffuse pseudomembranous degeneration.

  12. Degenerate target sites mediate rapid primed CRISPR adaptation.

    PubMed

    Fineran, Peter C; Gerritzen, Matthias J H; Suárez-Diez, María; Künne, Tim; Boekhorst, Jos; van Hijum, Sacha A F T; Staals, Raymond H J; Brouns, Stan J J

    2014-04-22

    Prokaryotes encode adaptive immune systems, called CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR associated), to provide resistance against mobile invaders, such as viruses and plasmids. Host immunity is based on incorporation of invader DNA sequences in a memory locus (CRISPR), the formation of guide RNAs from this locus, and the degradation of cognate invader DNA (protospacer). Invaders can escape type I-E CRISPR-Cas immunity in Escherichia coli K12 by making point mutations in the seed region of the protospacer or its adjacent motif (PAM), but hosts quickly restore immunity by integrating new spacers in a positive-feedback process termed "priming." Here, by using a randomized protospacer and PAM library and high-throughput plasmid loss assays, we provide a systematic analysis of the constraints of both direct interference and subsequent priming in E. coli. We have defined a high-resolution genetic map of direct interference by Cascade and Cas3, which includes five positions of the protospacer at 6-nt intervals that readily tolerate mutations. Importantly, we show that priming is an extremely robust process capable of using degenerate target regions, with up to 13 mutations throughout the PAM and protospacer region. Priming is influenced by the number of mismatches, their position, and is nucleotide dependent. Our findings imply that even outdated spacers containing many mismatches can induce a rapid primed CRISPR response against diversified or related invaders, giving microbes an advantage in the coevolutionary arms race with their invaders.

  13. Terminal arbor degeneration (TAD): a novel lesion produced by the antineoplastic agent, paclitaxel

    PubMed Central

    Bennett, Gary J.; Liu, Guo Kai; Xiao, Wen Hua; Jin, Hai Wei; Siau, Chiang

    2011-01-01

    The anti-neoplastic agent, paclitaxel, causes a dose-limiting distal, symmetrical, sensory peripheral neuropathy that is often accompanied by a neuropathic pain syndrome. In a low-dose model of paclitaxel-evoked painful peripheral neuropathy in the rat, we have shown that the drug causes degeneration of intraepidermal nerve fibers (IENFs), i.e., the fibers which give rise to the sensory afferent’s terminal receptor arbour. However, we did not find any evidence for axonal degeneration in samples taken at the mid-nerve level. Here we aimed to determine whether the absence of degenerating peripheral nerve axons was due to sampling a level that was too proximal. We used electron microscopy to study the distal-most branches of the nerves innervating the hind paw glabrous skin of normal and paclitaxel-treated rats. We confirmed that we sampled at a time when IENF degeneration was prominent. Because degeneration might be easier to detect with higher paclitaxel doses, we examined a four-fold cumulative dose range (8–32 mg/kg). We found no evidence of degeneration in the superficial subepidermal axon bundles (sSAB) that are located just a few microns below the epidermal basal lamina. Specifically, for all three dose groups there was no change in the number of sSAB per mm of epidermal border, no change in the number of axons per sSAB, and no change in the diameter of sSAB axons. We conclude that paclitaxel produces a novel type of lesion that is restricted to the afferent axon’s terminal arbor; we name this lesion “terminal arbor degeneration (TAD)”. PMID:21395870

  14. Lumbar disc degeneration below a long arthrodesis (performed for scoliosis in adults) to L4 or L5.

    PubMed

    Harding, Ian J; Charosky, Sebastian; Vialle, Raphael; Chopin, Daniel H

    2008-02-01

    A retrospective analysis of adults treated with long instrumented fusion for scoliosis from the thoracic spine proximally to L4 or L5. To evaluate the long-term clinical outcomes as well as radiological changes in distal unfused mobile segments and to evaluate factors that may predispose to distal disc degeneration and/or poor outcome. A total of 151 mobile segments in 85 patients (65 female), mean age 43.2 (range 21-68), were studied. Curve type, number of fused levels and pelvic incidence were recorded. Clinical outcome was measured using the Whitecloud function scale and disc degeneration using the UCLA disc degeneration score. Spinal balance, local segmental angulations and lumbar lordosis were measured pre- and post-operatively as well as at the most recent follow up--mean 9.3 years (range 7-19). A total of 62% of patients had a good or excellent outcome. Eleven had a poor outcome of which ten underwent extension of fusion--five for pain alone, three for pain with stenosis and two for pseudarthroses. Pre-operative disc degeneration was often asymmetric and was slightly greater in older patients. Overall, there was a significant deterioration in disc degeneration (P < 0.0001) that did not correlate with clinical outcome. Disc degeneration correlated with the recent sagittal balance (Anova F = 14.285, P < 0.001) and the most recent lordosis (Anova F = 4.057, P = 0.048). The post-operative sagittal balance and local L5-S1 sagittal angulation correlated to L4 and L5 degeneration, respectively. There was no correlation between degeneration and age, pre-operative degenerative score, pelvic incidence, sacral slope, number of fused levels or distal level of fusion. Disc degeneration does occur below an arthrodesis for scoliosis in adults which does not correlate with clinical outcome. The correlation of loss of sagittal balance with disc degeneration may be as a result of degeneration causing the loss of balance or vice versa, i.e. sagittal imbalance causing

  15. FAIM-L regulation of XIAP degradation modulates Synaptic Long-Term Depression and Axon Degeneration

    PubMed Central

    Martínez-Mármol, Ramón; Barneda-Zahonero, Bruna; Soto, David; Andrés, Rosa Maria; Coccia, Elena; Gasull, Xavier; Planells-Ferrer, Laura; Moubarak, Rana S.; Soriano, Eduardo; Comella, Joan X.

    2016-01-01

    Caspases have recently emerged as key regulators of axonal pruning and degeneration and of long-term depression (LTD), a long-lasting form of synaptic plasticity. However, the mechanism underlying these functions remains unclear. In this context, XIAP has been shown to modulate these processes. The neuron-specific form of FAIM protein (FAIM-L) is a death receptor antagonist that stabilizes XIAP protein levels, thus preventing death receptor-induced neuronal apoptosis. Here we show that FAIM-L modulates synaptic transmission, prevents chemical-LTD induction in hippocampal neurons, and thwarts axon degeneration after nerve growth factor (NGF) withdrawal. Additionally, we demonstrate that the participation of FAIM-L in these two processes is dependent on its capacity to stabilize XIAP protein levels. Our data reveal FAIM-L as a regulator of axonal degeneration and synaptic plasticity. PMID:27767058

  16. Impaired Mitochondrial Energy Production Causes Light-Induced Photoreceptor Degeneration Independent of Oxidative Stress.

    PubMed

    Jaiswal, Manish; Haelterman, Nele A; Sandoval, Hector; Xiong, Bo; Donti, Taraka; Kalsotra, Auinash; Yamamoto, Shinya; Cooper, Thomas A; Graham, Brett H; Bellen, Hugo J

    2015-07-01

    Two insults often underlie a variety of eye diseases including glaucoma, optic atrophy, and retinal degeneration--defects in mitochondrial function and aberrant Rhodopsin trafficking. Although mitochondrial defects are often associated with oxidative stress, they have not been linked to Rhodopsin trafficking. In an unbiased forward genetic screen designed to isolate mutations that cause photoreceptor degeneration, we identified mutations in a nuclear-encoded mitochondrial gene, ppr, a homolog of human LRPPRC. We found that ppr is required for protection against light-induced degeneration. Its function is essential to maintain membrane depolarization of the photoreceptors upon repetitive light exposure, and an impaired phototransduction cascade in ppr mutants results in excessive Rhodopsin1 endocytosis. Moreover, loss of ppr results in a reduction in mitochondrial RNAs, reduced electron transport chain activity, and reduced ATP levels. Oxidative stress, however, is not induced. We propose that the reduced ATP level in ppr mutants underlies the phototransduction defect, leading to increased Rhodopsin1 endocytosis during light exposure, causing photoreceptor degeneration independent of oxidative stress. This hypothesis is bolstered by characterization of two other genes isolated in the screen, pyruvate dehydrogenase and citrate synthase. Their loss also causes a light-induced degeneration, excessive Rhodopsin1 endocytosis and reduced ATP without concurrent oxidative stress, unlike many other mutations in mitochondrial genes that are associated with elevated oxidative stress and light-independent photoreceptor demise. PMID:26176594

  17. Treatment of Symptomatic Lumbar Disc Degeneration with the VariLift-L Interbody Fusion System: Retrospective Review of 470 Cases

    PubMed Central

    Neely, Warren F.; Fichtel, Frank; del Monaco, Diana Cardenas

    2016-01-01

    Background Many first generation stand-alone fusion cages required endplate decortication and surgical impaction during the procedure resulting in segmental subsidence, implant migration and loss of lordosis postoperatively. The primary objective of this study was to evaluate radiographically, in a large series of patients, whether engineering and design modifications incorporated in a specific stand-alone, expandable interbody fusion device (VariLift®-L) adequately addressed previously recognized deficiencies of stand-alone interbody cages. Methods In this retrospective chart review of 470 patients (642 treated levels), we evaluated radiographic evidence of fusion, subsidence and migration following a one- or two-level PLIF procedure utilizing this stand-alone expandable interbody fusion device. A secondary objective was to corroborate the low morbidity and symptomatic improvements achieved with previous interbody cage devices used to treat symptomatic disc degeneration. Results The average postoperative followup was 3.9 ± 1.8 years and a solid fusion rate of 94% was achieved among patients with ≥ 9 months of radiographic followup. Subsidence > 3 mm was noted at 10 levels with no cases of device migration. Composite back pain severity scores improved from 8.5 ± 1.5 preoperatively to 0.8 ± 1.5 at final followup (p<0.001) and 94% of patients met or exceeded the minimal clinical important difference of 3.8 points. Eighteen patients required reoperation following the index procedure; 16 of these patients were treated for adjacent segment disease. Conclusions (LOE) The VariLift-L device has excellent clinical and technical performance characteristics, providing adequate stabilization of the anterior column without the need for supplemental posterior instrumentation. Level of Evidence IV. IRB Approval: Expedited Federal Register Categories 5& 7: Methodist IRB 3/30/2011; Informed Consent statement: retrospective data collection, patients signed consent forms

  18. Cervical facet dislocation adjacent to the fused motion segment.

    PubMed

    Yokoyama, Kunio; Kawanishi, Masahiro; Yamada, Makoto; Tanaka, Hidekazu; Ito, Yutaka; Kuroiwa, Toshihiko

    2016-01-01

    This study reports on a case that forces re-examination of merits and demerits of anterior cervical fusion. A 79-year-old male was brought to the emergency room (ER) of our hospital after he fell and struck the occipital region of his head following excessive alcohol consumption. Four years prior, he had undergone anterior cervical discectomy and fusion of C5/6 and a magnetic resonance imaging (MRI) performed 3 years after this surgery indicated that he was suffering from degeneration of C6/7 intervertebral discs. After arriving at the ER, he presented motor impairment at level C7 and lower of manual muscle testing grade 1 as well as moderate loss of physical sensation from the trunk and peripheries of both upper limbs to the peripheries of both lower limbs (Frankel B). Cervical computed tomography (CT) indicated anterior dislocation of C6/7, and MRI indicated severe spinal cord edema. We performed manipulative reduction of C6/7 with the patient under general anesthesia. Next, we performed laminectomy on C5-T1 and posterior fusion on C6/7. Postoperative CT indicated that cervical alignment had improved, and MRI indicated that the spinal cord edema observed prior to surgery had been mitigated. Three months after surgery, motor function and sensory impairment of the lower limbs had improved, and the patient was ambulatory upon discharge from the hospital (Frankel D). In the present case, although C5 and 6 were rigidly fused, degeneration of the C6/7 intervertebral disc occurred and stability was compromised. As a result, even slight trauma placed a severe dynamic burden on the facet joint of C6/7, which led to dislocation.

  19. Localization of Drosophila retinal degeneration B, a membrane- associated phosphatidylinositol transfer protein

    PubMed Central

    1993-01-01

    The Drosophila retinal degeneration B (rdgB) mutation causes abnormal photoreceptor response and light-enhanced retinal degeneration. Immunoblots using polyclonal anti-rdgB serum showed that rdgB is a 160- kD membrane protein. The antiserum localized the rdgB protein in photoreceptors, antennae, and regions of the Drosophila brain, indicating that the rdgB protein functions in many sensory and neuronal cells. In photoreceptors, the protein localized adjacent to the rhabdomeres, in the vicinity of the subrhabdomeric cisternae. The rdgB protein's amino-terminal 281 residues are > 40% identical to the rat brain phosphatidylinositol transfer protein (PI-TP). A truncated rdgB protein, which contains only this amino-terminal domain, possesses a phosphatidylinositol transfer activity in vitro. The remaining 773 carboxyl terminal amino acids have additional functional domains. Nitrocellulose overlay experiments reveal that an acidic amino acid domain, adjacent to the PI transfer domain, binds 45Ca+2. Six hydrophobic segments are found in the middle of the putative translation product and likely function as membrane spanning domains. These results suggest that the rdgB protein, unlike the small soluble PI-TPs, is a membrane-associated PI-TP, which may be directly regulated by light-induced changes in intracellular calcium. PMID:8354691

  20. Degeneration of serotonergic neurons in amyotrophic lateral sclerosis: a link to spasticity.

    PubMed

    Dentel, Christel; Palamiuc, Lavinia; Henriques, Alexandre; Lannes, Béatrice; Spreux-Varoquaux, Odile; Gutknecht, Lise; René, Frédérique; Echaniz-Laguna, Andoni; Gonzalez de Aguilar, Jose-Luis; Lesch, Klaus Peter; Meininger, Vincent; Loeffler, Jean-Philippe; Dupuis, Luc

    2013-02-01

    Spasticity is a common and disabling symptom observed in patients with central nervous system diseases, including amyotrophic lateral sclerosis, a disease affecting both upper and lower motor neurons. In amyotrophic lateral sclerosis, spasticity is traditionally thought to be the result of degeneration of the upper motor neurons in the cerebral cortex, although degeneration of other neuronal types, in particular serotonergic neurons, might also represent a cause of spasticity. We performed a pathology study in seven patients with amyotrophic lateral sclerosis and six control subjects and observed that central serotonergic neurons suffer from a degenerative process with prominent neuritic degeneration, and sometimes loss of cell bodies in patients with amyotrophic lateral sclerosis. Moreover, distal serotonergic projections to spinal cord motor neurons and hippocampus systematically degenerated in patients with amyotrophic lateral sclerosis. In SOD1 (G86R) mice, a transgenic model of amyotrophic lateral sclerosis, serotonin levels were decreased in brainstem and spinal cord before onset of motor symptoms. Furthermore, there was noticeable atrophy of serotonin neuronal cell bodies along with neuritic degeneration at disease onset. We hypothesized that degeneration of serotonergic neurons could underlie spasticity in amyotrophic lateral sclerosis and investigated this hypothesis in vivo using tail muscle spastic-like contractions in response to mechanical stimulation as a measure of spasticity. In SOD1 (G86R) mice, tail muscle spastic-like contractions were observed at end-stage. Importantly, they were abolished by 5-hydroxytryptamine-2b/c receptors inverse agonists. In line with this, 5-hydroxytryptamine-2b receptor expression was strongly increased at disease onset. In all, we show that serotonergic neurons degenerate during amyotrophic lateral sclerosis, and that this might underlie spasticity in mice. Further research is needed to determine whether inverse

  1. Shell nuclear explosions in degenerate dwarfs

    NASA Astrophysics Data System (ADS)

    Kuznetsov, O. A.; Tutukov, A. V.; Chechetkin, V. M.

    1989-08-01

    Numerical gas dynamics simulations are used to study shell nuclear explosions of degenerate carbon-oxygen dwarfs with masses of 1.17, 1.36, and 1.42 solar masses. It is assumed that the calorific capacity of the burning shell matter is between 5 X 10 to the 17th and 5 X 10 to the 18th erg/g. It is shown that, at a low calorific capacity, a remnant may form if the mass of the shell is less than 90 percent of the mass of the degenerate dwarf. In the case of high calorific capacity, a remnant may form only if the mass of the shell is less than half of the dwarf's mass.

  2. NEUTRINO PROCESSES IN PARTIALLY DEGENERATE NEUTRON MATTER

    SciTech Connect

    Bacca, S.; Hally, K.; Liebendoerfer, M.; Perego, A.; Pethick, C. J.; Schwenk, A.

    2012-10-10

    We investigate neutrino processes for conditions reached in simulations of core-collapse supernovae. In regions where neutrino-matter interactions play an important role, matter is partially degenerate, and we extend earlier work that addressed the degenerate regime. We derive expressions for the spin structure factor in neutron matter, which is a key quantity required for evaluating rates of neutrino processes. We show that, for essentially all conditions encountered in the post-bounce phase of core-collapse supernovae, it is a very good approximation to calculate the spin relaxation rates in the nondegenerate limit. We calculate spin relaxation rates based on chiral effective field theory interactions and find that they are typically a factor of two smaller than those obtained using the standard one-pion-exchange interaction alone.

  3. Inflammation in age-related macular degeneration.

    PubMed

    Ozaki, Ema; Campbell, Matthew; Kiang, Anna-Sophia; Humphries, Marian; Doyle, Sarah L; Humphries, Peter

    2014-01-01

    Age-related macular degeneration (AMD) is the leading cause of legal blindness in elderly individuals in the developed world, affecting 30-50 million people worldwide. AMD primarily affects the macular region of the retina that is responsible for the majority of central, color and daytime vision. The presence of drusen, extracellular protein aggregates that accumulate under the retinal pigment epithelium (RPE), is a major pathological hallmark in the early stages of the disease. The end stage 'dry' and 'wet' forms of the disease culminate in vision loss and are characterized by focal degeneration of the RPE and cone photoreceptors, and choroidal neovascularization (CNV), respectively. Being a multifactorial and genetically heterogeneous disease, the pathophysiology of AMD remains unclear, yet, there is ample evidence supporting immunological and inflammatory processes. Here, we review the recent literature implicating some of these immune processes in human AMD and in animal models. PMID:24664703

  4. Degeneration and regeneration of ganglion cell axons.

    PubMed

    Weise, J; Ankerhold, R; Bähr, M

    2000-01-15

    The retino-tectal system has been used to study developmental aspects of axon growth, synapse formation and the establishment of a precise topographic order as well as degeneration and regeneration of adult retinal ganglion cell (RGC) axons after axonal lesion. This paper reviews some novel findings that provide new insights into the mechanisms of developmental RGC axon growth, pathfinding, and target formation. It also focuses on the cellular and molecular cascades that underlie RGC degeneration following an axonal lesion and on some therapeutic strategies to enhance survival of axotomized RGCs in vivo. In addition, this review deals with problems related to the induction of regeneration after axonal lesion in the adult CNS using the retino-tectal system as model. Different therapeutic approaches to promote RGC regeneration and requirements for specific target formation of regenerating RGCs in vitro and in vivo are discussed. PMID:10649506

  5. Inflammation in intervertebral disc degeneration and regeneration

    PubMed Central

    Molinos, Maria; Almeida, Catarina R.; Caldeira, Joana; Cunha, Carla; Gonçalves, Raquel M.; Barbosa, Mário A.

    2015-01-01

    Intervertebral disc (IVD) degeneration is one of the major causes of low back pain, a problem with a heavy economic burden, which has been increasing in prevalence as populations age. Deeper knowledge of the complex spatial and temporal orchestration of cellular interactions and extracellular matrix remodelling is critical to improve current IVD therapies, which have so far proved unsatisfactory. Inflammation has been correlated with degenerative disc disease but its role in discogenic pain and hernia regression remains controversial. The inflammatory response may be involved in the onset of disease, but it is also crucial in maintaining tissue homeostasis. Furthermore, if properly balanced it may contribute to tissue repair/regeneration as has already been demonstrated in other tissues. In this review, we focus on how inflammation has been associated with IVD degeneration by describing observational and in vitro studies as well as in vivo animal models. Finally, we provide an overview of IVD regenerative therapies that target key inflammatory players. PMID:25673296

  6. Immunology of age-related macular degeneration

    PubMed Central

    Ambati, Jayakrishna; Atkinson, John P.; Gelfand, Bradley D.

    2014-01-01

    Age-related macular degeneration (AMD) is a leading cause of blindness in aged individuals. Recent advances have highlighted the essential role of immune processes in the development, progression and treatment of AMD. In this Review we discuss recent discoveries related to the immunological aspects of AMD pathogenesis. We outline the diverse immune cell types, inflammatory activators and pathways that are involved. Finally, we discuss the future of inflammation-directed therapeutics to treat AMD in the growing aged population. PMID:23702979

  7. Dichromatic Langmuir waves in degenerate quantum plasma

    SciTech Connect

    Dubinov, A. E. Kitayev, I. N.

    2015-06-15

    Langmuir waves in fully degenerate quantum plasma are considered. It is shown that, in the linear approximation, Langmuir waves are always dichromatic. The low-frequency component of the waves corresponds to classical Langmuir waves, while the high-frequency component, to free-electron quantum oscillations. The nonlinear problem on the profile of dichromatic Langmuir waves is solved. Solutions in the form of a superposition of waves and in the form of beatings of its components are obtained.

  8. Degenerate Bose gases with uniform loss

    NASA Astrophysics Data System (ADS)

    Grišins, Pjotrs; Rauer, Bernhard; Langen, Tim; Schmiedmayer, Jörg; Mazets, Igor E.

    2016-03-01

    We theoretically investigate a weakly interacting degenerate Bose gas coupled to an empty Markovian bath. We show that in the universal phononic limit the system evolves towards an asymptotic state where an emergent temperature is set by the quantum noise of the outcoupling process. For situations typically encountered in experiments, this mechanism leads to significant cooling. Such dissipative cooling supplements conventional evaporative cooling and dominates in settings where thermalization is highly suppressed, such as in a one-dimensional quasicondensate.

  9. [Epidemiology of age related macular degeneration].

    PubMed

    Leveziel, N; Delcourt, C; Zerbib, J; Dollfus, H; Kaplan, J; Benlian, P; Coscas, G; Souied, E H; Soubrane, G

    2009-06-01

    Age-related macular degeneration (ARMD) is a multifactorial and polygenic disease and is the main cause of vision loss in developed countries. The environmental factors of ARMD can modify prevalence and incidence of this disease. This article is a review of the main environmental factors currently recognized as at risk or protective factor for ARMD. Modification of these factors is of crucial importance because it could delay the onset of exudative or atrophic forms of the disease. PMID:19515460

  10. Sarcomatous degeneration in a nasopharyngeal angiofibroma.

    PubMed

    Donald, P J

    1979-01-01

    Malignant degeneration in a juvenile nasopharyngeal angiofibroma has been reported in the literature in only four patients. All of these persons had been previously treated for cure with gamma irradiation. The case report of a 47-year-old man with a 31-year history of nasal obstruction is presented. A recurrence excised 18 months after initial removal of an angiofibroma revealed the surprising diagnosis of fibrosarcoma.

  11. Calabi-Yau manifolds and their degenerations.

    PubMed

    Tosatti, Valentino

    2012-07-01

    Calabi-Yau manifolds are geometric objects of central importance in several branches of mathematics, including differential geometry, algebraic geometry, and mathematical physics. In this paper, we give a brief introduction to the subject aimed at a general mathematical audience and present some of our results that shed some light on the possible ways in which families of Calabi-Yau manifolds can degenerate. PMID:22257362

  12. Propagation of disturbances in degenerate quantum systems

    NASA Astrophysics Data System (ADS)

    Chancellor, Nicholas; Haas, Stephan

    2011-07-01

    Disturbances in gapless quantum many-body models are known to travel an unlimited distance throughout the system. Here, we explore this phenomenon in finite clusters with degenerate ground states. The specific model studied here is the one-dimensional J1-J2 Heisenberg Hamiltonian at and close to the Majumdar-Ghosh point. Both open and periodic boundary conditions are considered. Quenches are performed using a local magnetic field. The degenerate Majumdar-Ghosh ground state allows disturbances which carry quantum entanglement to propagate throughout the system and thus dephase the entire system within the degenerate subspace. These disturbances can also carry polarization, but not energy, as all energy is stored locally. The local evolution of the part of the system where energy is stored drives the rest of the system through long-range entanglement. We also examine approximations for the ground state of this Hamiltonian in the strong field limit and study how couplings away from the Majumdar-Ghosh point affect the propagation of disturbances. We find that even in the case of approximate degeneracy, a disturbance can be propagated throughout a finite system.

  13. Hypertrophic olivary degeneration secondary to pontine haemorrhage.

    PubMed

    Wein, Sara; Yan, Bernard; Gaillard, Frank

    2015-07-01

    We report a 58-year-old man who developed hyptertrophic olivary degeneration (HOD) after haemorrhage of a cavernous malformation in the pons. Lesions of the triangle of Guillain and Mollaret (the dentatorubro-olivary pathway) may lead to HOD, a secondary transsynaptic degeneration of the inferior olivary nucleus. HOD is considered unique because the degenerating olive initially becomes hypertrophic rather than atrophic. The primary lesion causing pathway interruption is often haemorrhage, either due to hypertension, trauma, surgery or, as in our patient, a vascular malformation such as a cavernoma. Ischaemia and demyelination can also occasionally be the inciting events. The classic clinical presentation of HOD is palatal myoclonus, although not all patients with HOD develop this symptom. The imaging features of HOD evolve through characteristic phases. The clue to the diagnosis of HOD is recognition of the distinct imaging stages and identification of a remote primary lesion in the triangle of Guillain and Mollaret. Familiarity with the classic imaging findings of this rare phenomenon is necessary in order to avoid misdiagnosis and prevent unnecessary intervention.

  14. 3D visualization of the lumbar facet joint after degeneration using propagation phase contrast micro-tomography

    PubMed Central

    Cao, Yong; Zhang, Yi; Yin, Xianzheng; Lu, Hongbin; Hu, Jianzhong; Duan, Chunyue

    2016-01-01

    Lumbar facet joint (LFJ) degeneration is believed to be an important cause of low back pain (LBP). Identifying the morphological changes of the LFJ in the degeneration process at a high-resolution level could be meaningful for our better understanding of the possible mechanisms underlying this process. In the present study, we determined the 3D morphology of the LFJ using propagation phase contrast micro-tomography (PPCT) in rats to assess the subtle changes that occur during the degeneration process. PPCT provides vivid 3D images of micromorphological changes in the LFJ during its degeneration process, and the changes in the subchondral bone occurred earlier than in the cartilage during the early stage of degeneration of the LFJ. The delineation of this alteration was similar to that with the histological method. Our findings demonstrated that PPCT could serve as a valuable tool for 3D visualization of the morphology of the LFJ by providing comprehensive information about the cartilage and the underlying subchondral bone and their changes during degeneration processes. It might also have great potential for providing effective diagnostic tools to track changes in the cartilage and to evaluate the effects of therapeutic interventions for LFJ degeneration in preclinical studies. PMID:26907889

  15. Disc in Flames: Roles of TNF-α and IL-1β in Intervertebral Disc Degeneration

    PubMed Central

    Johnson, Zariel I.; Schoepflin, Zachary R.; Choi, Hyowon; Shapiro, Irving M.; Risbud, Makarand V.

    2016-01-01

    The intervertebral disc is an important mechanical structure that allows range of motion of the spinal column. Degeneration of the intervertebral disc, incited by aging, traumatic insult, genetic predisposition, or other factors, is often defined by functional and structural changes in the tissue, including excessive breakdown of the extracellular matrix, increased disc cell senescence and death, and compromised biomechanical function of the tissue. Intervertebral disc degeneration is strongly correlated with low back pain, which is a highly prevalent and costly condition, significantly contributing to loss in productivity and health care costs. Disc degeneration is a chronic, progressive condition, and current therapies are limited and often focused on symptomatic pain relief rather than curtailing the progression of the disease. Inflammatory processes, exacerbated by cytokines TNF-α and IL-1β are believed to be key mediators of disc degeneration and low back pain. In this review, we describe the contributions of TNF-α and IL-1β to changes seen during disc degeneration at the cellular and tissue level, new evidence suggesting a link between infection of the spine and low back pain, and the emerging therapeutic modalities aimed at combating these processes. PMID:26388614

  16. Kangaroo rats exhibit spongiform degeneration of the central auditory system similar to that found in gerbils.

    PubMed

    McGinn, M D; Faddis, B T

    1997-02-01

    Kangaroo rats develop spongiform degeneration of the central auditory system similar to that seen in the gerbil. Light microscopic and transmission electron microscopic study of the cochlear nucleus and auditory nerve root (ANR) of Dipodomys deserti and D. merriami show that spongiform lesions develop in dendrites and oligodendrocytes of the cochlear nucleus and in oligodendrocytes of the ANR that are morphologically indistinguishable from those extensively described in the Mongolian gerbil, Meriones unguiculatus. As in Mongolian gerbils, the spongiform degeneration in Dipodomys were much more numerous in animals continually exposed to modest levels of low-frequency noise (< 75 dB SPL). The kangaroo rats with extensive spongiform degeneration also show slightly, but significantly, elevated auditory brainstem evoked response (ABR) thresholds to low-frequency stimuli, a result also found in Mongolian gerbils. These results suggest that the elevated ABR thresholds may be the result of spongiform degeneration. Because low-frequency noise-induced spongiform degeneration has now been shown in the cochlear nucleus of animals from separate families of Rodentia (Heteromyidae and Muridae), the possibility should be investigated that similar noise-induced degenerative changes occur in the central auditory system of other mammals with good low-frequency hearing.

  17. Exchange coupling between laterally adjacent nanomagnets

    NASA Astrophysics Data System (ADS)

    Dey, H.; Csaba, G.; Bernstein, G. H.; Porod, W.

    2016-09-01

    We experimentally demonstrate exchange-coupling between laterally adjacent nanomagnets. Our results show that two neighboring nanomagnets that are each antiferromagnetically exchange-coupled to a common ferromagnetic bottom layer can be brought into strong ferromagnetic interaction. Simulations show that interlayer exchange coupling effectively promotes ferromagnetic alignment between the two nanomagnets, as opposed to antiferromagnetic alignment due to dipole-coupling. In order to experimentally demonstrate the proposed scheme, we fabricated arrays of pairs of elongated, single-domain nanomagnets. Magnetic force microscopy measurements show that most of the pairs are ferromagnetically ordered. The results are in agreement with micromagnetic simulations. The presented scheme can achieve coupling strengths that are significantly stronger than dipole coupling, potentially enabling far-reaching applications in Nanomagnet Logic, spin-wave devices and three-dimensional storage and computing.

  18. Boundary Layers of Air Adjacent to Cylinders

    PubMed Central

    Nobel, Park S.

    1974-01-01

    Using existing heat transfer data, a relatively simple expression was developed for estimating the effective thickness of the boundary layer of air surrounding cylinders. For wind velocities from 10 to 1000 cm/second, the calculated boundary-layer thickness agreed with that determined for water vapor diffusion from a moistened cylindrical surface 2 cm in diameter. It correctly predicted the resistance for water vapor movement across the boundary layers adjacent to the (cylindrical) inflorescence stems of Xanthorrhoea australis R. Br. and Scirpus validus Vahl and the leaves of Allium cepa L. The boundary-layer thickness decreased as the turbulence intensity increased. For a turbulence intensity representative of field conditions (0.5) and for νwindd between 200 and 30,000 cm2/second (where νwind is the mean wind velocity and d is the cylinder diameter), the effective boundary-layer thickness in centimeters was equal to [Formula: see text]. PMID:16658855

  19. Effective Hamiltonians for Coriolis-coupled nearly degenerate modes: Illustrative examples

    NASA Astrophysics Data System (ADS)

    Krishnan, Mangala S.; Carrington, Tucker, Jr.

    1993-11-01

    Using an angular momentum dependent Bogoliubov-Tyablikov (BT) transformation technique effective rotational Hamiltonians are derived for four molecules all of which have a pair of nearly degenerate strongly coupled vibrational modes. The BT transformation is applied to a two-vibrational-mode Hamiltonian obtained by using perturbation theory to eliminate the coupling between all but the nearly degenerate modes. Energy levels computed from the BT effective rotational Hamiltonians and accurate variational calculations agree very well. BT effective Hamiltonians are derived and tested for ozone, formaldehyde, its singly deuterated analog, and chlorodifluoromethane.

  20. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake...

  1. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake...

  2. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake...

  3. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake...

  4. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake...

  5. Rare earth nanoparticles prevent retinal degeneration induced by intracellular peroxides:

    NASA Astrophysics Data System (ADS)

    Chen, Junping; Patil, Swanand; Seal, Sudipta; McGinnis, James F.

    2006-11-01

    Photoreceptor cells are incessantly bombarded with photons of light, which, along with the cells' high rate of oxygen metabolism, continuously exposes them to elevated levels of toxic reactive oxygen intermediates (ROIs). Vacancy-engineered mixed-valence-state cerium oxide nanoparticles (nanoceria particles) scavenge ROIs. Our data show that nanoceria particles prevent increases in the intracellular concentrations of ROIs in primary cell cultures of rat retina and, in vivo, prevent loss of vision due to light-induced degeneration of photoreceptor cells. These data indicate that the nanoceria particles may be effective in inhibiting the progression of ROI-induced cell death, which is thought to be involved in macular degeneration, retinitis pigmentosa and other blinding diseases, as well as the ROI-induced death of other cell types in diabetes, Alzheimer's disease, atherosclerosis, stroke and so on. The use of nanoceria particles as a direct therapy for multiple diseases represents a novel strategy and suggests that they may represent a unique platform technology.

  6. Mutations in PNPLA6 are linked to photoreceptor degeneration and various forms of childhood blindness

    PubMed Central

    Kmoch, S.; Majewski, J.; Ramamurthy, V.; Cao, S.; Fahiminiya, S.; Ren, H.; MacDonald, I.M.; Lopez, I.; Sun, V.; Keser, V.; Khan, A.; Stránecký, V.; Hartmannová, H.; Přistoupilová, A.; Hodaňová, K.; Piherová, L.; Kuchař, L.; Baxová, A.; Chen, R.; Barsottini, O.G.P.; Pyle, A.; Griffin, H.; Splitt, M.; Sallum, J.; Tolmie, J.L.; Sampson, J.R.; Chinnery, P.; Canada, Care4Rare; Banin, E.; Sharon, D.; Dutta, S.; Grebler, R.; Helfrich-Foerster, C.; Pedroso, J.L.; Kretzschmar, D.; Cayouette, M.; Koenekoop, R.K.

    2015-01-01

    Blindness due to retinal degeneration affects millions of people worldwide, but many disease-causing mutations remain unknown. PNPLA6 encodes the patatin-like phospholipase domain containing protein 6, also known as neuropathy target esterase (NTE), which is the target of toxic organophosphates that induce human paralysis due to severe axonopathy of large neurons. Mutations in PNPLA6 also cause human spastic paraplegia characterized by motor neuron degeneration. Here we identify PNPLA6 mutations in childhood blindness in seven families with retinal degeneration, including Leber congenital amaurosis and Oliver McFarlane syndrome. PNPLA6 localizes mostly at the inner segment plasma membrane in photo-receptors and mutations in Drosophila PNPLA6 lead to photoreceptor cell death. We also report that lysophosphatidylcholine and lysophosphatidic acid levels are elevated in mutant Drosophila. These findings show a role for PNPLA6 in photoreceptor survival and identify phospholipid metabolism as a potential therapeutic target for some forms of blindness. PMID:25574898

  7. The effective density of randomly moving electrons and related characteristics of materials with degenerate electron gas

    NASA Astrophysics Data System (ADS)

    Palenskis, V.

    2014-04-01

    Interpretation of the conductivity of metals, of superconductors in the normal state and of semiconductors with highly degenerate electron gas remains a significant issue if consideration is based on the classical statistics. This study is addressed to the characterization of the effective density of randomly moving electrons and to the evaluation of carrier diffusion coefficient, mobility, and other parameters by generalization of the widely published experimental results. The generalized expressions have been derived for various kinetic parameters attributed to the non-degenerate and degenerate electron gas, by analyzing a random motion of the single type carriers in homogeneous materials. The values of the most important kinetic parameters for different metals are also systematized and discussed. It has been proved that Einstein's relation between the diffusion coefficient and the drift mobility of electrons is held for any level of degeneracy if the effective density of randomly moving carriers is properly taken into account.

  8. Age-dependent neuronal and synaptic degeneration in mice transgenic for the C terminus of the amyloid precursor protein.

    PubMed

    Oster-Granite, M L; McPhie, D L; Greenan, J; Neve, R L

    1996-11-01

    The molecular basis for the degeneration of neurons and the deposition of amyloid in plaques and in the cerebrovasculature in Alzheimer's disease (AD) is incompletely understood. We have proposed that one molecule common to these abnormal processes is a fragment of the Alzheimer amyloid precursor protein (APP) comprising the C-terminal 100 amino acids of this molecule (APP-C100). We tested this hypothesis by creating transgenic mice expressing APP-C100 in the brain. We report here that aging (18-28 month) APP-C100 transgenic mice exhibit profound degeneration of neurons and synapses in Ammon's horn and the dentate gyrus of the hippocampal formation. Of the 106 transgenic mice between 8 and 28 months of age that were examined, all of those older than 18 months displayed severe hippocampal degeneration. The numerous degenerating axonal profiles contained increased numbers of neurofilaments, whorls of membrane, and accumulations of debris resembling secondary lysosomes near the cell body. The dendrites of degenerating granule and pyramidal cells contained disorganized, wavy microtubules. Cerebral blood vessels had thickened refractile basal laminae, and microglia laden with debris lay adjacent to larger venous vessels. Mice transgenic for Flag-APP-C100 (in which the hydrophilic Flag tag was fused to the N terminus of APP-C100) showed a similar degree of neurodegeneration in the hippocampal formation as early as 12 months of age. The 45 control mice displayed only occasional necrotic cells and no extensive cell degeneration in the same brain regions. These findings show that APP-C100 is capable of causing some of the neuropathological features of AD. PMID:8824314

  9. Stress Wave Interaction Between Two Adjacent Blast Holes

    NASA Astrophysics Data System (ADS)

    Yi, Changping; Johansson, Daniel; Nyberg, Ulf; Beyglou, Ali

    2016-05-01

    Rock fragmentation by blasting is determined by the level and state of stress in the rock mass subjected to blasting. With the application of electronic detonators, some researchers stated that it is possible to achieve improved fragmentation through stress wave superposition with very short delay times. This hypothesis was studied through theoretical analysis in the paper. First, the stress in rock mass induced by a single-hole shot was analyzed with the assumptions of infinite velocity of detonation and infinite charge length. Based on the stress analysis of a single-hole shot, the stress history and tensile stress distribution between two adjacent holes were presented for cases of simultaneous initiation and 1 ms delayed initiation via stress superposition. The results indicated that the stress wave interaction is local around the collision point. Then, the tensile stress distribution at the extended line of two adjacent blast holes was analyzed for a case of 2 ms delay. The analytical results showed that the tensile stress on the extended line increases due to the stress wave superposition under the assumption that the influence of neighboring blast hole on the stress wave propagation can be neglected. However, the numerical results indicated that this assumption is unreasonable and yields contrary results. The feasibility of improving fragmentation via stress wave interaction with precise initiation was also discussed. The analysis in this paper does not support that the interaction of stress waves improves the fragmentation.

  10. Vector polarons in a degenerate electron system

    NASA Astrophysics Data System (ADS)

    Clougherty, Dennis P.; Foell, Charles A.

    2004-08-01

    We consider a one-dimensional model of an electron in a doubly (or nearly) degenerate band that interacts with elastic distortions. We show that the electron equations of motion reduce to a set of coupled nonlinear Schrödinger equations. For the case of interband electron-phonon coupling stemming from local Jahn-Teller interactions, multicomponent self-localized polaron solutions-vector polarons- are described and classified. The phase diagram for the different types of vector polarons in this model is presented. By interpreting the components of the orbital doublet as those of spin- (1)/(2) , our results can also be used to describe bound magnetic polarons.

  11. Relativistic Bernstein waves in a degenerate plasma

    SciTech Connect

    Ali, Muddasir; Hussain, Azhar; Murtaza, G.

    2011-09-15

    Bernstein mode for a relativistic degenerate electron plasma is investigated. Using relativistic Vlasov-Maxwell equations, a general expression for the conductivity tensor is derived and then employing Fermi-Dirac distribution function a generalized dispersion relation for the Bernstein mode is obtained. Two limiting cases, i.e., non-relativistic and ultra-relativistic are discussed. The dispersion relations obtained are also graphically presented for some specific values of the parameters depicting how the propagation characteristics of Bernstein waves as well as the Upper Hybrid oscillations are modified with the increase in plasma number density.

  12. Aneutronic Fusion in a Degenerate Plasma

    SciTech Connect

    S. Son; N.J. Fisch

    2004-09-03

    In a Fermi-degenerate plasma, the electronic stopping of a slow ion is smaller than that given by the classical formula, because some transitions between the electron states are forbidden. The bremsstrahlung losses are then smaller, so that the nuclear burning of an aneutronic fuel is more efficient. Consequently, there occurs a parameter regime in which self-burning is possible. Practical obstacles in this regime that must be overcome before net energy can be realized include the compression of the fuel to an ultra dense state and the creation of a hot spot.

  13. Survivin is expressed in degenerated nucleus pulposus cells and is involved in proliferation and the prevention of apoptosis in vitro

    PubMed Central

    LIN, YAZHOU; YUE, BIN; XIANG, HONGFEI; LIU, YONG; MA, XUEXIAO; CHEN, BOHUA

    2016-01-01

    Survivin is a unique inhibitor of apoptosis, which is frequently present within degenerated human nucleus pulposus (NP) cells. Survivin has been extensively investigated using proliferation and apoptosis assays in tumor cells; however, studies conducted on survivin in degenerative NP cells remain limited to date. The aim of the present study was to investigate survivin expression and its effects on the proliferation and apoptosis of degenerated NP cells in vitro. The expression levels of survivin in the NP cells of patients (>45 years) with lumbar disc degenerative disease and the NP cells of patients (<25 years) with lumbar vertebra fracture were assessed by reverse transcription-quantitative polymerase chain reaction. The effects on in vitro proliferation and apoptosis were investigated through transfection with a specific small interfering (si)RNA. The results of the present study demonstrated that survivin was expressed in the degenerated NP cells, but was undetectable in normal NP cells at the mRNA level. Survivin suppression following transfection with a specific survivin-siRNA reduced the proliferation rate of NP cells and enhanced sensitization to pro-apoptotic stimuli. Therefore, survivin was shown to be expressed and exhibit an important role in the proliferation and prevention of apoptosis of degenerated NP cells. Studies on survivin in NP cells may aid in increasing the understanding of the complex processes underlying NP cell degeneration, and could provide fundamental information for gene therapy to inhibit this degeneration in vitro. PMID:26648308

  14. Bone morphogenetic protein-2 provokes interleukin-18-induced human intervertebral disc degeneration

    PubMed Central

    Ye, S.; Ju, B.; Wang, H.

    2016-01-01

    Objectives Interleukin 18 (IL-18) is a regulatory cytokine that degrades the disc matrix. Bone morphogenetic protein-2 (BMP-2) stimulates synthesis of the disc extracellular matrix. However, the combined effects of BMP-2 and IL-18 on human intervertebral disc degeneration have not previously been reported. The aim of this study was to investigate the effects of the anabolic cytokine BMP-2 and the catabolic cytokine IL-18 on human nucleus pulposus (NP) and annulus fibrosus (AF) cells and, therefore, to identify potential therapeutic and clinical benefits of recombinant human (rh)BMP-2 in intervertebral disc degeneration. Methods Levels of IL-18 were measured in the blood of patients with intervertebral disc degenerative disease and in control patients. Human NP and AF cells were cultured in a NP cell medium and treated with IL-18 or IL-18 plus BMP-2. mRNA levels of target genes were measured by real-time polymerase chain reaction, and protein levels of aggrecan, type II collagen, SOX6, and matrix metalloproteinase 13 (MMP13) were assessed by western blot analysis. Results The serum level of patients (IL-18) increased significantly with the grade of IVD degeneration. There was a dramatic alteration in IL-18 level between the advanced degeneration (Grade III to V) group and the normal group (p = 0.008) Furthermore, IL-18 induced upregulation of the catabolic regulator MMP13 and downregulation of the anabolic regulators aggrecan, type II collagen, and SOX6 at 24 hours, contributing to degradation of disc matrix enzymes. However, BMP-2 antagonised the IL-18 induced upregulation of aggrecan, type II collagen, and SOX6, resulting in reversal of IL-18 mediated disc degeneration. Conclusions BMP-2 is anti-catabolic in human NP and AF cells, and its effects are partially mediated through provocation of the catabolic effect of IL-18. These findings indicate that BMP-2 may be a unique therapeutic option for prevention and reversal of disc degeneration. Cite this article: S. Ye

  15. Configuration optimization of dampers for adjacent buildings under seismic excitations

    NASA Astrophysics Data System (ADS)

    Bigdeli, Kasra; Hare, Warren; Tesfamariam, Solomon

    2012-12-01

    Passive coupling of adjacent structures is known to be an effective method to reduce undesirable vibrations and structural pounding effects. Past results have shown that reducing the number of dampers can considerably decrease the cost of implementation and does not significantly decrease the efficiency of the system. The main objective of this study was to find the optimal arrangement of a limited number of dampers to minimize interstorey drift. Five approaches to solving the resulting bi-level optimization problem are introduced and examined (exhaustive search, inserting dampers, inserting floors, locations of maximum relative velocity and a genetic algorithm) and the numerical efficiency of each method is examined. The results reveal that the inserting damper method is the most efficient and reliable method, particularly for tall structures. It was also found that increasing the number of dampers does not necessarily increase the efficiency of the system. In fact, increasing the number of dampers can exacerbate the dynamic response of the system.

  16. Progressive retinal degeneration in ranch mink.

    PubMed

    Hadlow, W J

    1984-01-01

    Retinal degeneration was prevalent in a large group of sapphire and pastel mink (Mustela vison) kept for studies on slow viral diseases. Nearly 78% of those two to eight years old were affected. The retinopathy was equally common in both sexes but more frequent in sapphires (85%) than in pastels (63%), and it was severe more often in sapphires than in pastels. By light microscopy, the primary change appeared to be progressive degeneration of fully developed photoreceptors, beginning in their outer segments. In many mink, including some younger ones, the rods and cones and outer nuclear layer had disappeared from all but the far periphery of the fundus. The inner retinal layers were spared until late in the disease, and the pigment epithelium remained essentially unchanged. The cause of the retinopathy was not established. It may represent an abiotrophy in which the structural integrity of the photoreceptors began to wane in many mink after they reached two years of age. Apart from reducing visual acuity, the retinopathy has implications for the photoperiodic control of fur growth and reproduction in this highly light-sensitive carnivore. PMID:6710807

  17. Iatrogenic corneal perforation in Terrien Marginal Degeneration.

    PubMed

    M R, Kursiah

    2013-04-01

    This case report is about a rare disease with unusual presentation. Failure to recognise atypical presentation may lead to error in managing the patient and cause disastrous complications. Here we highlight a case of Terrien Marginal Degeneration in both eyes with atypical presentation; namely pseudopterygium. A 22 year old man was referred to our centre for iatrogenic right eye corneal perforation after having an atypical pterygium removed at another hospital. On arrival, his vision was 1/60 in both eyes with bilateral cornea Terrien Marginal Degeneration. His right eye anterior chamber was deep with a conjunctival flap covering the perforation site which was located from the 2.30 - 3.30 clock position nasally with no aqueous leak. However after a day his right eye anterior chamber became flat and there was fast aqueous leak from the perforation site. An emergency C shaped peripheral corneal lamellar keratoplasty was performed to seal the perforation. Post operatively his right eye improved to 6/24.

  18. Nodular fasciitis with degeneration and regression.

    PubMed

    Yanagisawa, Akihiro; Okada, Hideki

    2008-07-01

    Nodular fasciitis is a benign reactive proliferation that is frequently misdiagnosed as a sarcoma. This article describes a case of nodular fasciitis of 6-month duration located in the cheek, which degenerated and spontaneously regressed after biopsy. The nodule was fixed to the zygoma but was free from the overlying skin. The mass was 3.0 cm in diameter and demonstrated high signal intensity on T2-weighted magnetic resonance imaging. A small part of the lesion was biopsied. Pathological and immunohistochemical examinations identified the nodule as nodular fasciitis with myxoid histology. One month after the biopsy, the mass showed decreased signal intensity on T2-weighted images and measured 2.2 cm in size. The signal on T2-weighted images showed time-dependent decreases, and the mass continued to reduce in size throughout the follow-up period. The lesion presented as hypointense to the surrounding muscles on T2-weighted images and was 0.4 cm in size at 2 years of follow-up. This case demonstrates that nodular fasciitis with myxoid histology can change to that with fibrous appearance gradually with time, thus bringing about spontaneous regression. Degeneration may be involved in the spontaneous regression of nodular fasciitis with myxoid appearance. The mechanism of regression, unclarified at present, should be further studied. PMID:18650753

  19. Changes in ganglion cells during retinal degeneration.

    PubMed

    Saha, Susmita; Greferath, Ursula; Vessey, Kirstan A; Grayden, David B; Burkitt, Anthony N; Fletcher, Erica L

    2016-08-01

    Inherited retinal degeneration such as retinitis pigmentosa (RP) is associated with photoreceptor loss and concomitant morphological and functional changes in the inner retina. It is not known whether these changes are associated with changes in the density and distribution of synaptic inputs to retinal ganglion cells (RGCs). We quantified changes in ganglion cell density in rd1 and age-matched C57BL/6J-(wildtype, WT) mice using the immunocytochemical marker, RBPMS. Our data revealed that following complete loss of photoreceptors, (∼3months of age), there was a reduction in ganglion cell density in the peripheral retina. We next examined changes in synaptic inputs to A type ganglion cells by performing double labeling experiments in mice with the ganglion cell reporter lines, rd1-Thy1 and age-matched wildtype-Thy1. Ribbon synapses were identified by co-labelling with CtBP2 (RIBEYE) and conventional synapses with the clustering molecule, gephyrin. ON RGCs showed a significant reduction in RIBEYE-immunoreactive synapse density while OFF RGCs showed a significant reduction in the gephyrin-immmunoreactive synapse density. Distribution patterns of both synaptic markers across the dendritic trees of RGCs were unchanged. The change in synaptic inputs to RGCs was associated with a reduction in the number of immunolabeled rod bipolar and ON cone bipolar cells. These results suggest that functional changes reported in ganglion cells during retinal degeneration could be attributed to loss of synaptic inputs. PMID:27132232

  20. Progressive retinal degeneration in ranch mink.

    PubMed

    Hadlow, W J

    1984-01-01

    Retinal degeneration was prevalent in a large group of sapphire and pastel mink (Mustela vison) kept for studies on slow viral diseases. Nearly 78% of those two to eight years old were affected. The retinopathy was equally common in both sexes but more frequent in sapphires (85%) than in pastels (63%), and it was severe more often in sapphires than in pastels. By light microscopy, the primary change appeared to be progressive degeneration of fully developed photoreceptors, beginning in their outer segments. In many mink, including some younger ones, the rods and cones and outer nuclear layer had disappeared from all but the far periphery of the fundus. The inner retinal layers were spared until late in the disease, and the pigment epithelium remained essentially unchanged. The cause of the retinopathy was not established. It may represent an abiotrophy in which the structural integrity of the photoreceptors began to wane in many mink after they reached two years of age. Apart from reducing visual acuity, the retinopathy has implications for the photoperiodic control of fur growth and reproduction in this highly light-sensitive carnivore.

  1. Degenerate parametric oscillation in quantum membrane optomechanics

    NASA Astrophysics Data System (ADS)

    Benito, Mónica; Sánchez Muñoz, Carlos; Navarrete-Benlloch, Carlos

    2016-02-01

    The promise of innovative applications has triggered the development of many modern technologies capable of exploiting quantum effects. But in addition to future applications, such quantum technologies have already provided us with the possibility of accessing quantum-mechanical scenarios that seemed unreachable just a few decades ago. With this spirit, in this work we show that modern optomechanical setups are mature enough to implement one of the most elusive models in the field of open system dynamics: degenerate parametric oscillation. Introduced in the eighties and motivated by its alleged implementability in nonlinear optical resonators, it rapidly became a paradigm for the study of dissipative phase transitions whose corresponding spontaneously broken symmetry is discrete. However, it was found that the intrinsic multimode nature of optical cavities makes it impossible to experimentally study the model all the way through its phase transition. In contrast, here we show that this long-awaited model can be implemented in the motion of a mechanical object dispersively coupled to the light contained in a cavity, when the latter is properly driven with multichromatic laser light. We focus on membranes as the mechanical element, showing that the main signatures of the degenerate parametric oscillation model can be studied in state-of-the-art setups, thus opening the possibility of analyzing spontaneous symmetry breaking and enhanced metrology in one of the cleanest dissipative phase transitions. In addition, the ideas put forward in this work would allow for the dissipative preparation of squeezed mechanical states.

  2. Potent Antiscrapie Activities of Degenerate Phosphorothioate Oligonucleotides

    PubMed Central

    Kocisko, David A.; Vaillant, Andrew; Lee, Kil Sun; Arnold, Kevin M.; Bertholet, Nadine; Race, Richard E.; Olsen, Emily A.; Juteau, Jean-Marc; Caughey, Byron

    2006-01-01

    Although transmissible spongiform encephalopathies (TSEs) are incurable, a key therapeutic approach is prevention of conversion of the normal, protease-sensitive form of prion protein (PrP-sen) to the disease-specific protease-resistant form of prion protein (PrP-res). Here degenerate phosphorothioate oligonucleotides (PS-ONs) are introduced as low-nM PrP-res conversion inhibitors with strong antiscrapie activities in vivo. Comparisons of various PS-ON analogs indicated that hydrophobicity and size were important, while base composition was only minimally influential. PS-ONs bound avidly to PrP-sen but could be displaced by sulfated glycan PrP-res inhibitors, indicating the presence of overlapping binding sites. Labeled PS-ONs also bound to PrP-sen on live cells and were internalized. This binding likely accounts for the antiscrapie activity. Prophylactic PS-ON treatments more than tripled scrapie survival periods in mice. Survival times also increased when PS-ONs were mixed with scrapie brain inoculum. With these antiscrapie activities and their much lower anticoagulant activities than that of pentosan polysulfate, degenerate PS-ONs are attractive new compounds for the treatment of TSEs. PMID:16495266

  3. Evolutionary scenarios for double degenerate systems

    NASA Astrophysics Data System (ADS)

    Sarna, M. J.; Marks, P. B.; Connon Smith, Robert

    1996-03-01

    We propose evolutionary scenarios in which double degenerate white dwarf systems can be produced through one or two phases of stable mass transfer. We consider Algol-type evolution as well as evolution involving first a stage of common-envelope (CE) evolution followed by a phase of stable mass transfer. We also show that the final orbital period of double white dwarf systems depends on the period after the first phase of mass transfer, and that there is critical period (the bifurcation period) above which systems evolve to orbital periods of the order of days and below which systems evolve towards very short orbital periods (a few hours). This probably corresponds to the observation that double degenerate systems have periods either of hours or of days. We also find a limit on the stability of mass transfer for systems that first go through a phase of CE evolution. We suggest that our new evolutionary scheme involving two stages of stable mass transfer and our scheme involving first CE evolution followed by stable mass transfer should be included in population synthesis models.

  4. Metabolic anatomy of paraneoplastic cerebellar degeneration

    SciTech Connect

    Anderson, N.E.; Posner, J.B.; Sidtis, J.J.; Moeller, J.R.; Strother, S.C.; Dhawan, V.; Rottenberg, D.A.

    1988-06-01

    Eleven patients with acquired cerebellar degeneration (10 of whom had paraneoplastic cerebellar degeneration (PCD)) were evaluated using neuropsychological tests and /sup 18/F-fluorodeoxyglucose/positron emission tomography to (1) quantify motor, cognitive, and metabolic abnormalities; (2) determine if characteristic alterations in the regional cerebral metabolic rate for glucose (rCMRGlc) are associated with PCD; and (3) correlate behavioral and metabolic measures of disease severity. Eighteen volunteer subjects served as normal controls. Although some PCD neuropsychological test scores were abnormal, these results could not, in general, be dissociated from the effects of dysarthria and ataxia. rCMRGlc was reduced in patients with PCD (versus normal control subjects) in all regions except the brainstem. Analysis of patient and control rCMRGlc data using a mathematical model of regional metabolic interactions revealed two metabolic pattern descriptors, SSF1 and SSF2, which distinguished patients with PCD from normal control subjects; SSF2, which described a metabolic coupling between cerebellum, cuneus, and posterior temporal, lateral frontal, and paracentral cortex, correlated with quantitative indices of cerebellar dysfunction. Our inability to document substantial intellectual impairment in 7 of 10 patients with PCD contrasts with the 50% incidence of dementia in PCD reported by previous investigators. Widespread reductions in PCD rCMRGlc may result from the loss of cerebellar efferents to thalamus and forebrain structures, a reverse cerebellar diaschisis.

  5. [Acquired polycystic degeneration of the kidneys].

    PubMed

    Kreisel-Büstgens, C; Büstgens, L; Graben, N

    1990-12-15

    Kidneys of patients with advanced renal insufficiency undergo polycystic transformation, described as acquired cystic degeneration (ACD). In 118 chronic dialysis patients clinical data were compared with sonographic findings of their 221 cirrhotic kidneys: 74 (63%) patients showed distinctly discernible renal cysts: 19 patients hat one single cyst, nine patients had two to eight cysts, 46 patients had more than eight cysts. Accordingly 39% of patients had ACD. Cystic transformation was of the same degree on both sides and in a few cases so marked that a formal discrimination to congenital cystic disease seemed impossible. Cystic degeneration was not influenced by patient's age, sex or underlying renal disease, but was dependent on the duration of both, renal disease and dialysis treatment. After eight years 71% of dialysis patients had ACD. In coincidence with cystic transformation the size of the kidneys apparently normalized and Hb-concentration rose from 8 to 10 g/dl. Complications were seen in six patients: two severe retroperitoneal bleedings and four hypernephroma were observed. The etiology of cystic transformation and its possible role as precancerosis are discussed.

  6. Radiative seesaw model with degenerate Majorana dark matter

    NASA Astrophysics Data System (ADS)

    Nomura, Takaaki; Okada, Hiroshi; Orikasa, Yuta

    2016-06-01

    We study a three-loop-induced neutrino mass model with exotic vectorlike isospin doublet leptons which contain a dark matter candidate. Then we explore lepton flavor violations and dark matter physics in a coannihilation system. In this paper, the nearly degenerate Majorana fermion dark matter can naturally be achieved at the two-loop level, while the mass splitting can be larger than O (200 ) keV which is required from the constraint of the direct detection search with spin-independent inelastic scattering through the Z -boson portal. As a result, a monochromatic photon excess, with threshold energy greater than O (200 ) keV , is predicted in our model and could be measured through indirect detection experiments such as INTEGRAL.

  7. Age-related macular degeneration and the complement system.

    PubMed

    Khandhadia, S; Cipriani, V; Yates, J R W; Lotery, A J

    2012-02-01

    Age-related macular degeneration (AMD) is the leading cause of blindness in the developed world. It is a complex multifactorial disease, and despite new advances in treatment, many patients still succumb to visual impairment. The complement pathway has been implicated in the pathogenesis of many diseases, and recently variants in several genes encoding complement pathway proteins have been associated with AMD. Complement proteins have been found in histological specimens of eyes with AMD. Altered levels of both intrinsic complement proteins and activated products have been found in the circulation of patients with AMD. Complement activation may be triggered by oxidative stress, resulting from retinal exposure to incoming light; indeed an inter-play between these two pathological processes seems to exist. Finally, complement inhibitors are currently being evaluated in clinical trials. This article reviews the role of the complement system in AMD, and the potential of complement inhibition in preventing the devastating blindness resulting from this disease.

  8. Coexistence of Weyl fermion and massless triply degenerate nodal points

    NASA Astrophysics Data System (ADS)

    Weng, Hongming; Fang, Chen; Fang, Zhong; Dai, Xi

    2016-10-01

    By using first-principles calculations, we propose that WC-type ZrTe is a new type of topological semimetal (TSM). It has six pairs of chiral Weyl nodes in its first Brillouin zone, but it is distinguished from other existing TSMs by having an additional two paris of massless fermions with triply degenerate nodal points as proposed in the isostructural compounds TaN and NbN. The mirror symmetry, threefold rotational symmetry, and time-reversal symmetry require all of the Weyl nodes to have the same velocity vectors and locate at the same energy level. The Fermi arcs on different surfaces are shown, which may be measured by future experiments. It demonstrates that the "material universe" can support more intriguing particles simultaneously.

  9. Mechanisms of axon degeneration: from development to disease.

    PubMed

    Saxena, Smita; Caroni, Pico

    2007-10-01

    Axon degeneration is an active, tightly controlled and versatile process of axon segment self-destruction. Although not involving cell death, it resembles apoptosis in its logics. It involves three distinct steps: induction of competence in specific neurons, triggering of degeneration at defined axon segments of competent neurons, and rapid fragmentation and removal of the segments. The mechanisms that initiate degeneration are specific to individual settings, but the final pathway of pruning is shared; it involves microtubule disassembly, axon swellings, axon fragmentation, and removal of the remnants by locally recruited phagocytes. The tight regulatory properties of axon degeneration distinguish it from passive loss phenomena, and confer significance to processes that involve it. Axon degeneration has prominent roles in development, upon lesions and in disease. In development, it couples the progressive specification of neurons and circuits to the removal of defined axon branches. Competence might involve transcriptional switches, and local triggering can involve axon guidance molecules and synaptic activity patterns. Lesion-induced Wallerian degeneration is inhibited in the presence of Wld(S) fusion protein in neurons; it involves early local, and later, distal degeneration. It has recently become clear that like in other settings, axon degeneration in disease is a rapid and specific process, which should not be confused with a variety of disease-related pathologies. Elucidating the specific mechanisms that initiate axon degeneration should open up new avenues to investigate principles of circuit assembly and plasticity, to uncover mechanisms of disease progression, and to identify ways of protecting synapses and axons in disease.

  10. Time-series Spectroscopy of Two Candidate Double Degenerates in the Open Cluster NGC 6633

    NASA Astrophysics Data System (ADS)

    Williams, Kurtis A.; Serna-Grey, Donald; Chakraborty, Subho; Gianninas, A.; Canton, Paul A.

    2015-12-01

    SNe Ia are heavily used tools in precision cosmology, yet we still are not certain what the progenitor systems are. General plausibility arguments suggest there is potential for identifying double degenerate SN Ia progenitors in intermediate-age open star clusters. We present time-resolved high-resolution spectroscopy of two white dwarfs (WDs) in the field of the open cluster NGC 6633 that had previously been identified as candidate double degenerates in the cluster. However, three hours of continuous observations of each candidate failed to detect any significant radial velocity variations at the ≳10 km s-1 level, making it highly unlikely that either WD is a double degenerate that will merge within a Hubble Time. The WD LAWDS NGC 6633 4 has a radial velocity inconsistent with cluster membership at the 2.5σ level, while the radial velocity of LAWDS NGC 6633 7 is consistent with cluster membership. We conservatively conclude that LAWDS 7 is a viable massive double degenerate candidate, though unlikely to be a Type Ia progenitor. Astrometric data from GAIA will likely be needed to determine if either WD is truly a cluster member. The data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.

  11. PGC-1α regulation of mitochondrial degeneration in experimental diabetic neuropathy.

    PubMed

    Choi, Joungil; Chandrasekaran, Krish; Inoue, Tatsuya; Muragundla, Anjaneyulu; Russell, James W

    2014-04-01

    Mitochondrial degeneration is considered to play an important role in the development of diabetic peripheral neuropathy in humans. Mitochondrial degeneration and the corresponding protein regulation associated with the degeneration were studied in an animal model of diabetic neuropathy. PGC-1α and its-regulated transcription factors including TFAM and NRF1, which are master regulators of mitochondrial biogenesis, are significantly downregulated in streptozotocin diabetic dorsal root ganglion (DRG) neurons. Diabetic mice develop peripheral neuropathy, loss of mitochondria, decreased mitochondrial DNA content and increased protein oxidation. Importantly, this phenotype is exacerbated in PGC-1α (-/-) diabetic mice, which develop a more severe neuropathy with reduced mitochondrial DNA and a further increase in protein oxidation. PGC-1α (-/-) diabetic mice develop an increase in total cholesterol and triglycerides, and a decrease in TFAM and NRF1 protein levels. Loss of PGC-1α causes severe mitochondrial degeneration with vacuolization in DRG neurons, coupled with reduced state 3 and 4 respiration, reduced expression of oxidative stress response genes and an increase in protein oxidation. In contrast, overexpression of PGC-1α in cultured adult mouse neurons prevents oxidative stress associated with increased glucose levels. The study provides new insights into the role of PGC-1α in mitochondrial regeneration in peripheral neurons and suggests that therapeutic modulation of PGC-1α function may be an attractive approach for treatment of diabetic neuropathy.

  12. TIME-SERIES SPECTROSCOPY OF TWO CANDIDATE DOUBLE DEGENERATES IN THE OPEN CLUSTER NGC 6633

    SciTech Connect

    Williams, Kurtis A.; Chakraborty, Subho; Serna-Grey, Donald; Gianninas, A.; Canton, Paul A.

    2015-12-15

    SNe Ia are heavily used tools in precision cosmology, yet we still are not certain what the progenitor systems are. General plausibility arguments suggest there is potential for identifying double degenerate SN Ia progenitors in intermediate-age open star clusters. We present time-resolved high-resolution spectroscopy of two white dwarfs (WDs) in the field of the open cluster NGC 6633 that had previously been identified as candidate double degenerates in the cluster. However, three hours of continuous observations of each candidate failed to detect any significant radial velocity variations at the ≳10 km s{sup −1} level, making it highly unlikely that either WD is a double degenerate that will merge within a Hubble Time. The WD LAWDS NGC 6633 4 has a radial velocity inconsistent with cluster membership at the 2.5σ level, while the radial velocity of LAWDS NGC 6633 7 is consistent with cluster membership. We conservatively conclude that LAWDS 7 is a viable massive double degenerate candidate, though unlikely to be a Type Ia progenitor. Astrometric data from GAIA will likely be needed to determine if either WD is truly a cluster member.

  13. Impaired Mitochondrial Energy Production Causes Light-Induced Photoreceptor Degeneration Independent of Oxidative Stress

    PubMed Central

    Jaiswal, Manish; Haelterman, Nele A.; Sandoval, Hector; Xiong, Bo; Donti, Taraka; Kalsotra, Auinash; Yamamoto, Shinya; Cooper, Thomas A.; Graham, Brett H.; Bellen, Hugo J.

    2015-01-01

    Two insults often underlie a variety of eye diseases including glaucoma, optic atrophy, and retinal degeneration—defects in mitochondrial function and aberrant Rhodopsin trafficking. Although mitochondrial defects are often associated with oxidative stress, they have not been linked to Rhodopsin trafficking. In an unbiased forward genetic screen designed to isolate mutations that cause photoreceptor degeneration, we identified mutations in a nuclear-encoded mitochondrial gene, ppr, a homolog of human LRPPRC. We found that ppr is required for protection against light-induced degeneration. Its function is essential to maintain membrane depolarization of the photoreceptors upon repetitive light exposure, and an impaired phototransduction cascade in ppr mutants results in excessive Rhodopsin1 endocytosis. Moreover, loss of ppr results in a reduction in mitochondrial RNAs, reduced electron transport chain activity, and reduced ATP levels. Oxidative stress, however, is not induced. We propose that the reduced ATP level in ppr mutants underlies the phototransduction defect, leading to increased Rhodopsin1 endocytosis during light exposure, causing photoreceptor degeneration independent of oxidative stress. This hypothesis is bolstered by characterization of two other genes isolated in the screen, pyruvate dehydrogenase and citrate synthase. Their loss also causes a light-induced degeneration, excessive Rhodopsin1 endocytosis and reduced ATP without concurrent oxidative stress, unlike many other mutations in mitochondrial genes that are associated with elevated oxidative stress and light-independent photoreceptor demise. PMID:26176594

  14. [Treatment of exudative age-related macular degeneration].

    PubMed

    Yuzawa, M

    2000-12-01

    I PROPHYLACTIC TREATMENT: We followed 75 eyes contralateral to eyes with exudative age-related macular degeneration (AMD), using indocyanine green angiography (IA), for more than one year. Hyperfluorescent areas in the late phase of IA were seen in 19 eyes at the initial examination, and in 25 eyes during follow-up. Exudative AMD developed in 9 of the 25 eyes. Using timetable analysis, we estimated that 11% of these 27 eyes developed AMD within one year and 55% within three years. The hyperfluorescent areas seen on IA appeared to be latent choroidal neovascularization (CNV) under the retinal pigment epithelium. We propose that photocoagulation aimed at hyperfluorescent areas should be considered in such cases. We performed prophylactic laser photocoagulation in 21 eyes, which were then followed up for at least six months. These eyes all had 10 or more serous drusen within 1,500 microns of the fovea and did not show hyperfluorescence, suggesting latent CNV in the late phase of IA. The majority or a small fraction of the serous drusen disappeared in 48% and 18% of the 21 eyes, respectively. CNV appeared adjacent to the laser scar in one eye (5%). Judging from these results, it is important to establish a method of definitively abolishing drusen and preventing the development of CNV. II TREATMENT OF CNV: Of 229 eyes which showed occult CNV in fluorescein angiography (FA), 124 eyes (54%) showed classic CNV outside the fovea on IA. One hundred and two of the 124 eyes (45%) underwent laser photocoagulation. We evaluated indocyanine green guided laser photocoagulation of extrafoveal CNV in 139 eyes. The success rate was 81% at 3 months after laser photocoagulation. This was estimated using timetable analyses to have decreased to 78% at one year and 71% at three years. Eighty percent of successfully treated eyes showed maintained or improved visual acuity. These results did not differ significantly from those obtained with laser photocoagulation based on FA findings. When

  15. Purkinje Cell Degeneration in pcd Mice Reveals Large Scale Chromatin Reorganization and Gene Silencing Linked to Defective DNA Repair*

    PubMed Central

    Baltanás, Fernando C.; Casafont, Iñigo; Lafarga, Vanesa; Weruaga, Eduardo; Alonso, José R.; Berciano, María T.; Lafarga, Miguel

    2011-01-01

    DNA repair protects neurons against spontaneous or disease-associated DNA damage. Dysfunctions of this mechanism underlie a growing list of neurodegenerative disorders. The Purkinje cell (PC) degeneration mutation causes the loss of nna1 expression and is associated with the postnatal degeneration of PCs. This PC degeneration dramatically affects nuclear architecture and provides an excellent model to elucidate the nuclear mechanisms involved in a whole array of neurodegenerative disorders. We used immunocytochemistry for histone variants and components of the DNA damage response, an in situ transcription assay, and in situ hybridization for telomeres to analyze changes in chromatin architecture and function. We demonstrate that the phosphorylation of H2AX, a DNA damage signal, and the trimethylation of the histone H4K20, a repressive mark, in extensive domains of genome are epigenetic hallmarks of chromatin in degenerating PCs. These histone modifications are associated with a large scale reorganization of chromatin, telomere clustering, and heterochromatin-induced gene silencing, all of them key factors in PC degeneration. Furthermore, ataxia telangiectasia mutated and 53BP1, two components of the DNA repair pathway, fail to be concentrated in the damaged chromatin compartments, even though the expression levels of their coding genes were slightly up-regulated. Although the mechanism by which Nna1 loss of function leads to PC neurodegeneration is undefined, the progressive accumulation of DNA damage in chromosome territories irreversibly compromises global gene transcription and seems to trigger PC degeneration and death. PMID:21700704

  16. A Novel Method to Simulate the Progression of Collagen Degeneration of Cartilage in the Knee: Data from the Osteoarthritis Initiative

    NASA Astrophysics Data System (ADS)

    Mononen, Mika E.; Tanska, Petri; Isaksson, Hanna; Korhonen, Rami K.

    2016-02-01

    We present a novel algorithm combined with computational modeling to simulate the development of knee osteoarthritis. The degeneration algorithm was based on excessive and cumulatively accumulated stresses within knee joint cartilage during physiological gait loading. In the algorithm, the collagen network stiffness of cartilage was reduced iteratively if excessive maximum principal stresses were observed. The developed algorithm was tested and validated against experimental baseline and 4-year follow-up Kellgren-Lawrence grades, indicating different levels of cartilage degeneration at the tibiofemoral contact region. Test groups consisted of normal weight and obese subjects with the same gender and similar age and height without osteoarthritic changes. The algorithm accurately simulated cartilage degeneration as compared to the Kellgren-Lawrence findings in the subject group with excess weight, while the healthy subject group’s joint remained intact. Furthermore, the developed algorithm followed the experimentally found trend of cartilage degeneration in the obese group (R2 = 0.95, p < 0.05 experiments vs. model), in which the rapid degeneration immediately after initiation of osteoarthritis (0-2 years, p < 0.001) was followed by a slow or negligible degeneration (2-4 years, p > 0.05). The proposed algorithm revealed a great potential to objectively simulate the progression of knee osteoarthritis.

  17. A Novel Method to Simulate the Progression of Collagen Degeneration of Cartilage in the Knee: Data from the Osteoarthritis Initiative

    NASA Astrophysics Data System (ADS)

    Mononen, Mika E.; Tanska, Petri; Isaksson, Hanna; Korhonen, Rami K.

    2016-02-01

    We present a novel algorithm combined with computational modeling to simulate the development of knee osteoarthritis. The degeneration algorithm was based on excessive and cumulatively accumulated stresses within knee joint cartilage during physiological gait loading. In the algorithm, the collagen network stiffness of cartilage was reduced iteratively if excessive maximum principal stresses were observed. The developed algorithm was tested and validated against experimental baseline and 4-year follow-up Kellgren-Lawrence grades, indicating different levels of cartilage degeneration at the tibiofemoral contact region. Test groups consisted of normal weight and obese subjects with the same gender and similar age and height without osteoarthritic changes. The algorithm accurately simulated cartilage degeneration as compared to the Kellgren-Lawrence findings in the subject group with excess weight, while the healthy subject group’s joint remained intact. Furthermore, the developed algorithm followed the experimentally found trend of cartilage degeneration in the obese group (R2 = 0.95, p < 0.05 experiments vs. model), in which the rapid degeneration immediately after initiation of osteoarthritis (0–2 years, p < 0.001) was followed by a slow or negligible degeneration (2–4 years, p > 0.05). The proposed algorithm revealed a great potential to objectively simulate the progression of knee osteoarthritis.

  18. A Novel Method to Simulate the Progression of Collagen Degeneration of Cartilage in the Knee: Data from the Osteoarthritis Initiative

    PubMed Central

    Mononen, Mika E.; Tanska, Petri; Isaksson, Hanna; Korhonen, Rami K.

    2016-01-01

    We present a novel algorithm combined with computational modeling to simulate the development of knee osteoarthritis. The degeneration algorithm was based on excessive and cumulatively accumulated stresses within knee joint cartilage during physiological gait loading. In the algorithm, the collagen network stiffness of cartilage was reduced iteratively if excessive maximum principal stresses were observed. The developed algorithm was tested and validated against experimental baseline and 4-year follow-up Kellgren-Lawrence grades, indicating different levels of cartilage degeneration at the tibiofemoral contact region. Test groups consisted of normal weight and obese subjects with the same gender and similar age and height without osteoarthritic changes. The algorithm accurately simulated cartilage degeneration as compared to the Kellgren-Lawrence findings in the subject group with excess weight, while the healthy subject group’s joint remained intact. Furthermore, the developed algorithm followed the experimentally found trend of cartilage degeneration in the obese group (R2 = 0.95, p < 0.05; experiments vs. model), in which the rapid degeneration immediately after initiation of osteoarthritis (0–2 years, p < 0.001) was followed by a slow or negligible degeneration (2–4 years, p > 0.05). The proposed algorithm revealed a great potential to objectively simulate the progression of knee osteoarthritis. PMID:26906749

  19. Relationship between liver degeneration and the production of dark firm dry meat in slaughtered pigs.

    PubMed

    Mori, C; Maeda, H; Yuasa, A

    1990-06-01

    Sixty-five of 77 slaughtered pigs with liver degeneration produced dark firm dry (DFD) meat. The biochemical properties of blood, liver and muscle of those pigs were examined. In the blood, the NEFA level was higher, which indicated the mobilization of lipids from adipose tissues. The serum CPK and LDH5 levels were higher, the enzymes being derived from muscle. In the degenerative liver with yellowish discoloration, the TG level was higher and the glycogen level was lower than in a normal liver. In the DFD muscle with the final pH above 6.0, both the glycogen level immediately after slaughter and the lactic acid level 24 hr after slaughter were lower than in a normal muscle with the final pH below 6.0. Five pigs exhausted experimentally by 53-hr fasting and hard exercise showed the same changes in the blood and liver as the pigs with liver degeneration. Four of the 5 exhausted pigs showed the same changes in the muscle as in DFD meat. From these data, it was confirmed that exhaustion before slaughter led to lipid accumulation in the liver and to a decrease in muscle glycogen, and consequently caused both liver degeneration and DFD meat in the same pig.

  20. Degenerate polygonal tilings in simple animal tissues

    NASA Astrophysics Data System (ADS)

    Hočevar, A.; Ziherl, P.

    2009-07-01

    The salient feature of one-cell-thick epithelia is their en face view, which reveals the polygonal cross section of the close-packed prismatic cells. The physical mechanisms that shape these tissues were hitherto explored using theories based on cell proliferation, which were either entirely topological or included certain morphogenetic forces. But mitosis itself may not be instrumental in molding the tissue. We show that the structure of simple epithelia can be explained by an equilibrium model where energy-degenerate polygons in an entropy-maximizing tiling are described by a single geometric parameter encoding their inflatedness. The two types of tilings found numerically—ordered and disordered—closely reproduce the patterns observed in Drosophila, Hydra, and Xenopus and they generalize earlier theoretical results. Free of a specific cell self-energy, cell-cell interaction, and cell division kinetics, our model provides an insight into the universality of living and inanimate two-dimensional cellular structures.

  1. Solitons in Degenerate Electron-Phonon Systems

    NASA Astrophysics Data System (ADS)

    Foell, Charles; Clougherty, Dennis

    2004-03-01

    We consider a 1øplus 1-dimensional model describing the coupling between degenerate electron states under local Jahn-Teller interactions. In the adiabatic approximation, the equations of motion are shown to reduce to a set of coupled non-linear Schrödinger equations in the electron fields. We demonstrate that in the continuum limit solitary waves of the wave-daughter wave type are stable for sufficiently strong on-site Coulomb repulsion. Our results may have relevance to describing the electronic and optical properties of quasi-one-dimensional systems such as halogen-bridged mixed-valence transition-metal linear-chain complexes (MX chains) and polymeric fullerides.

  2. Subwavelength total acoustic absorption with degenerate resonators

    NASA Astrophysics Data System (ADS)

    Yang, Min; Meng, Chong; Fu, Caixing; Li, Yong; Yang, Zhiyu; Sheng, Ping

    2015-09-01

    We report the experimental realization of perfect sound absorption by sub-wavelength monopole and dipole resonators that exhibit degenerate resonant frequencies. This is achieved through the destructive interference of two resonators' transmission responses, while the matching of their averaged impedances to that of air implies no backscattering, thereby leading to total absorption. Two examples, both using decorated membrane resonators (DMRs) as the basic units, are presented. The first is a flat panel comprising a DMR and a pair of coupled DMRs, while the second one is a ventilated short tube containing a DMR in conjunction with a sidewall DMR backed by a cavity. In both examples, near perfect absorption, up to 99.7%, has been observed with the airborne wavelength up to 1.2 m, which is at least an order of magnitude larger than the composite absorber. Excellent agreement between theory and experiment is obtained.

  3. Quantum Walk in Degenerate Spin Environments

    NASA Astrophysics Data System (ADS)

    Carlström, Johan; Prokof'ev, Nikolay; Svistunov, Boris

    2016-06-01

    We study the propagation of a hole in degenerate (paramagnetic) spin environments. This canonical problem has important connections to a number of physical systems, and is perfectly suited for experimental realization with ultracold atoms in an optical lattice. At the short-to-intermediate time scale that we can access using a stochastic-series-type numeric scheme, the propagation turns out to be distinctly nondiffusive with the probability distribution featuring minima in both space and time due to quantum interference, yet the motion is not ballistic, except at the beginning. We discuss possible scenarios for long-term evolution that could be explored with an unprecedented degree of detail in experiments with single-atom resolved imaging.

  4. [Epidemiology of age-related macular degeneration].

    PubMed

    Brandl, C; Stark, K J; Wintergerst, M; Heinemann, M; Heid, I M; Finger, R P

    2016-09-01

    Age-related macular degeneration (AMD) is the main cause of blindness in industrialized societies. Population-based epidemiological investigations generate important data on prevalence, incidence, risk factors, and future trends. This review summarizes the most important epidemiological studies on AMD with a focus on their transferability to Germany including existing evidence for the main risk factors for AMD development and progression. Future tasks, such as the standardization of grading systems and the use of recent retinal imaging technology in epidemiological studies are discussed. In Germany, epidemiological data on AMD are scarce. However, the need for epidemiological research in ophthalmology is currently being addressed by several recently started population-based studies. PMID:27541733

  5. Responses to light after retinal degeneration.

    PubMed

    Mrosovsky, N; Salmon, P A; Foster, R G; McCall, M A

    2000-01-01

    Transgenic rodless mice were given 1-h pulses of light of varying brightness at times of the night when they were normally active. The rodless mice showed decreases in locomotor activity during light pulses brighter than 2 lux; these decreases were significantly greater than those in wildtypes (ANOVA, P < 0.01). However, with very dim light, rodless mice showed no changes in activity, whereas wildtype mice actually increased their activity. It is suggested that irradiance detection could be enhanced by absence of image-forming vision. Enhanced inhibition of activity around twilight may be adaptive for mice in some circumstances and so help maintain genes for retinal degeneration in natural populations. PMID:10824261

  6. A computational model of motor neuron degeneration.

    PubMed

    Le Masson, Gwendal; Przedborski, Serge; Abbott, L F

    2014-08-20

    To explore the link between bioenergetics and motor neuron degeneration, we used a computational model in which detailed morphology and ion conductance are paired with intracellular ATP production and consumption. We found that reduced ATP availability increases the metabolic cost of a single action potential and disrupts K+/Na+ homeostasis, resulting in a chronic depolarization. The magnitude of the ATP shortage at which this ionic instability occurs depends on the morphology and intrinsic conductance characteristic of the neuron. If ATP shortage is confined to the distal part of the axon, the ensuing local ionic instability eventually spreads to the whole neuron and involves fasciculation-like spiking events. A shortage of ATP also causes a rise in intracellular calcium. Our modeling work supports the notion that mitochondrial dysfunction can account for salient features of the paralytic disorder amyotrophic lateral sclerosis, including motor neuron hyperexcitability, fasciculation, and differential vulnerability of motor neuron subpopulations.

  7. Mapping cerebellar degeneration in HIV/AIDS.

    PubMed

    Klunder, Andrea D; Chiang, Ming-Chang; Dutton, Rebecca A; Lee, Sharon E; Toga, Arthur W; Lopez, Oscar L; Aizenstein, Howard J; Becker, James T; Thompson, Paul M

    2008-11-19

    Progressive brain atrophy in HIV/AIDS is associated with impaired psychomotor performance, perhaps partly reflecting cerebellar degeneration; yet little is known about how HIV/AIDS affects the cerebellum. We visualized the three-dimensional profile of atrophy in 19 HIV-positive patients (age: 42.9+/-8.3 years) versus 15 healthy controls (age: 38.5+/-12.0 years). We localized consistent patterns of subregional atrophy with an image analysis method that automatically deforms each patient's scan, in three dimensions, to match a reference image. Atrophy was greatest in the posterior cerebellar vermis (14.9% deficit) and correlated with depression severity (P=0.009, corrected), but not with dementia, alcohol/substance abuse, CD4+T-cell counts, or viral load. Profound cerebellar deficits in HIV/AIDS (P=0.007, corrected) were associated with depression, suggesting a surrogate disease marker for antiretroviral trials.

  8. Degenerate R-S perturbation theory

    NASA Technical Reports Server (NTRS)

    Hirschfelder, J. O.; Certain, P. R.

    1973-01-01

    A concise, systematic procedure is given for determining the Rayleigh-Schrodinger energies and wave functions of degenerate states to arbitrarily high orders even when the degeneracies of the various states are resolved in arbitrary orders. The procedure is expressed in terms of an iterative cycle in which the energy through the (2n+1)st order is expressed in terms of the partially determined wave function through the n-th order. Both a direct and an operator derivation are given. The two approaches are equivalent and can be transcribed into each other. The direct approach deals with the wave functions (without the use of formal operators) and has the advantage that it resembles the usual treatment of nondegenerate perturbations and maintains close contact with the basic physics. In the operator approach, the wave functions are expressed in terms of infinite order operators which are determined by the successive resolution of the space of the zeroth order functions.

  9. Age-related macular degeneration: current treatments

    PubMed Central

    Hubschman, Jean Pierre; Reddy, Shantan; Schwartz, Steven D

    2009-01-01

    Purpose: Although important progress has been made in understanding age-related macular degeneration (AMD), management of the disease continues to be a challenge. AMD research has led to a widening of available treatment options and improved prognostic perspectives. This essay reviews these treatment options. Design: Interpretative essay. Methods: Literature review and interpretation. Results: Current treatments to preserve vision in patients with non-exudative AMD include antioxidant vitamins and mineral supplementations. Exudative AMD is currently most often treated monthly with anti-VEGF intravitreal injections. However, investigators are beginning to experiment with combination therapy and surgical approaches in an attempt to limit the number of treatment and reduce the financial burden on the health care system. Conclusion: By better understanding the basis and pathogenesis of AMD, newer therapies will continue to be developed that target specific pathways in patients with AMD, with the hoped for outcome of better management of the disease and improved visual acuity. PMID:19668560

  10. Effect of Fluoridated Sealants on Adjacent Tooth Surfaces

    PubMed Central

    Cagetti, M.G.; Carta, G.; Cocco, F.; Sale, S.; Congiu, G.; Mura, A.; Strohmenger, L.; Lingström, P.; Campus, G.

    2014-01-01

    A double-blind randomized clinical trial was performed in 6- to 7-yr-old schoolchildren to evaluate, in a 30-mo period, whether the caries increment on the distal surface of the second primary molars adjacent to permanent first molars sealed with fluoride release compounds would be lower with respect to those adjacent to permanent first molars sealed with a nonfluoridated sealant. In sum, 2,776 subjects were enrolled and randomly divided into 3 groups receiving sealants on sound first molars: high-viscosity glass ionomer cement (GIC group); resin-based sealant with fluoride (fluoride-RB group); and a resin-based sealant without fluoride (RB group). Caries (D1 – D3 level) was recorded on the distal surface of the second primary molar, considered the unit of analysis including only sound surfaces at the baseline. At baseline, no differences in caries prevalence were recorded in the 3 groups regarding the considered surfaces. At follow-up, the prevalence of an affected unit of analysis was statistically lower (p = .03) in the GIC and fluoride-RB groups (p = .04). In the GIC group, fewer new caries were observed in the unit of analysis respect to the other 2 groups. Incidence rate ratios (IRRs) were 0.70 (95% confidence interval: 0.50, 0.68; p < .01) for GIC vs. RB and 0.79 (95% confidence interval: 0.53, 1.04; p = .005) for fluoride-RB vs. RB. Caries incidence was significantly associated with low socioeconomic status (IRR = 1.18; 95% confidence interval: 1.10, 1.42; p = .05). Dental sealant high-viscosity GIC and fluoride-RB demonstrated protection against dental caries, and there was evidence that these materials afforded additional protection for the tooth nearest to the sealed tooth (clinical trial registration NCT01588210). PMID:24846910

  11. Crystallization and collapse in relativistically degenerate matter

    SciTech Connect

    Akbari-Moghanjoughi, M.

    2013-04-15

    In this paper, it is shown that a mass density limit exists beyond which the relativistically degenerate matter would crystallize. The mass density limit, found here, is quite analogous to the mass limit predicted by Chandrasekhar for a type of compact stars called white dwarfs (M{sub Ch} Asymptotically-Equal-To 1.43 Solar Mass). In this study, the old problem of white dwarf core collapse, which has been previously investigated by Chandrasekhar using hydrostatic stability criteria, is revisited in the framework of the quantum hydrodynamics model by inspection of the charge screening at atomic scales in the relativistic degeneracy plasma regime taking into account the relativistic Fermi-Dirac statistics and electron interaction features such as the quantum statistical pressure, Coulomb attraction, electron exchange-correlation, and quantum recoil effects. It is revealed that the existence of ion correlation and crystallization of matter in the relativistically degenerate plasma puts a critical mass density limit on white dwarf core region. It is shown that a white dwarf star with a core mass density beyond this critical limit can undergo the spontaneous core collapse (SCC). The SCC phenomenon, which is dominantly caused by the electron quantum recoil effect (interference and localization of the electron wave function), leads to a new exotic state of matter. In such exotic state, the relativistic electron degeneracy can lead the white dwarf crystallized core to undergo the nuclear fusion and an ultimate supernova by means of the volume reduction (due to the enhanced compressibility) and huge energy release (due to the increase in cohesive energy), under the stars huge inward gravitational pressure. Moreover, it is found that the SCC phenomenon is significantly affected by the core composition (it is more probable for heavier plasmas). The critical mass density found here is consistent with the values calculated for core density of typical white dwarf stars.

  12. Retrograde Axonal Degeneration in Parkinson Disease

    PubMed Central

    Tagliaferro, Patricia; Burke, Robert E.

    2016-01-01

    In spite of tremendous research efforts we have not yet achieved two of our principal therapeutic goals in the treatment of Parkinson’s disease (PD), to prevent its onward progression and to provide restoration of systems that have already been damaged by the time of diagnosis. There are many possible reasons for our inability to make progress. One possibility is that our efforts thus far may not have been directed towards the appropriate cellular compartments. Up until now research has been largely focused on the loss of neurons in the disease. Thus, neuroprotection approaches have been largely aimed at blocking mechanisms that lead to destruction of the neuronal cell body. Attempts to provide neurorestoration have been almost entirely focused on replacement of neurons. We herein review the evidence that the axonal component of diseased neuronal systems merit more of our attention. Evidence from imaging studies, from postmortem neurochemical studies, and from genetic animal models suggests that the axons of the dopaminergic system are involved predominantly and early in PD. Since the mechanisms of axonal destruction are distinct from those of neuron cell body degeneration, a focus on axonal neurobiology will offer new opportunities for preventing their degeneration. At present these mechanisms remain largely obscure. However, defining them is likely to offer new opportunities for neuroprotection. In relation to neurorestoration, while it has been classically believed that neurons of the adult central nervous system are incapable of new axon growth, recent evidence shows that this is not true for the dopaminergic projection. In conclusion, the neurobiology of axons is likely to offer many new approaches to protective and restorative therapeutics. PMID:27003783

  13. Muscle hypertrophy induced by myostatin inhibition accelerates degeneration in dysferlinopathy

    PubMed Central

    Lee, Yun-Sil; Lehar, Adam; Sebald, Suzanne; Liu, Min; Swaggart, Kayleigh A.; Talbot, C. Conover; Pytel, Peter; Barton, Elisabeth R.; McNally, Elizabeth M.; Lee, Se-Jin

    2015-01-01

    Myostatin is a secreted signaling molecule that normally acts to limit muscle growth. As a result, there is extensive effort directed at developing drugs capable of targeting myostatin to treat patients with muscle loss. One potential concern with this therapeutic approach in patients with muscle degenerative diseases like muscular dystrophy is that inducing hypertrophy may increase stress on dystrophic fibers, thereby accelerating disease progression. To investigate this possibility, we examined the effect of blocking the myostatin pathway in dysferlin-deficient (Dysf−/−) mice, in which membrane repair is compromised, either by transgenic expression of follistatin in skeletal muscle or by systemic administration of the soluble form of the activin type IIB receptor (ACVR2B/Fc). Here, we show that myostatin inhibition by follistatin transgene expression in Dysf−/− mice results in early improvement in histopathology but ultimately exacerbates muscle degeneration; this effect was not observed in dystrophin-deficient (mdx) mice, suggesting that accelerated degeneration induced by follistatin transgene expression is specific to mice lacking dysferlin. Dysf−/− mice injected with ACVR2B/Fc showed significant increases in muscle mass and amelioration of fibrotic changes normally seen in 8-month-old Dysf−/− mice. Despite these potentially beneficial effects, ACVR2B/Fc treatment caused increases in serum CK levels in some Dysf−/− mice, indicating possible muscle damage induced by hypertrophy. These findings suggest that depending on the disease context, inducing muscle hypertrophy by myostatin blockade may have detrimental effects, which need to be weighed against the potential gains in muscle growth and decreased fibrosis. PMID:26206886

  14. Muscle hypertrophy induced by myostatin inhibition accelerates degeneration in dysferlinopathy.

    PubMed

    Lee, Yun-Sil; Lehar, Adam; Sebald, Suzanne; Liu, Min; Swaggart, Kayleigh A; Talbot, C Conover; Pytel, Peter; Barton, Elisabeth R; McNally, Elizabeth M; Lee, Se-Jin

    2015-10-15

    Myostatin is a secreted signaling molecule that normally acts to limit muscle growth. As a result, there is extensive effort directed at developing drugs capable of targeting myostatin to treat patients with muscle loss. One potential concern with this therapeutic approach in patients with muscle degenerative diseases like muscular dystrophy is that inducing hypertrophy may increase stress on dystrophic fibers, thereby accelerating disease progression. To investigate this possibility, we examined the effect of blocking the myostatin pathway in dysferlin-deficient (Dysf(-/-)) mice, in which membrane repair is compromised, either by transgenic expression of follistatin in skeletal muscle or by systemic administration of the soluble form of the activin type IIB receptor (ACVR2B/Fc). Here, we show that myostatin inhibition by follistatin transgene expression in Dysf(-/-) mice results in early improvement in histopathology but ultimately exacerbates muscle degeneration; this effect was not observed in dystrophin-deficient (mdx) mice, suggesting that accelerated degeneration induced by follistatin transgene expression is specific to mice lacking dysferlin. Dysf(-/-) mice injected with ACVR2B/Fc showed significant increases in muscle mass and amelioration of fibrotic changes normally seen in 8-month-old Dysf(-/-) mice. Despite these potentially beneficial effects, ACVR2B/Fc treatment caused increases in serum CK levels in some Dysf(-/-) mice, indicating possible muscle damage induced by hypertrophy. These findings suggest that depending on the disease context, inducing muscle hypertrophy by myostatin blockade may have detrimental effects, which need to be weighed against the potential gains in muscle growth and decreased fibrosis.

  15. 9 CFR 311.35 - Muscular inflammation, degeneration, or infiltration.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Muscular inflammation, degeneration... PARTS § 311.35 Muscular inflammation, degeneration, or infiltration. (a) If muscular lesions are found... carcass shall be condemned. (b) If muscular lesions are found to be distributed in such a manner or to...

  16. [Depression in Patients with Age-Related Macular Degeneration].

    PubMed

    Narváez, Yamile Reveiz; Gómez-Restrepo, Carlos

    2012-09-01

    Age-related macular degeneration is a cause for disability in the elderly since it greatly affects their quality of life and increases depression likelihood. This article discusses the negative effect depression has on patients with age-related macular degeneration and summarizes the interventions available for decreasing their depression index. PMID:26572116

  17. [Depression in Patients with Age-Related Macular Degeneration].

    PubMed

    Narváez, Yamile Reveiz; Gómez-Restrepo, Carlos

    2012-09-01

    Age-related macular degeneration is a cause for disability in the elderly since it greatly affects their quality of life and increases depression likelihood. This article discusses the negative effect depression has on patients with age-related macular degeneration and summarizes the interventions available for decreasing their depression index.

  18. Retinas in a Dish Peek into Inherited Retinal Degeneration.

    PubMed

    Duong, Thu T; Vasireddy, Vidyullatha; Mills, Jason A; Bennett, Jean

    2016-06-01

    Human retinal degeneration can cause blindness, and the lack of relevant model systems has made identifying underlying mechanisms challenging. Parfitt et al. (2016) generate three-dimensional retinal tissue from patient-derived induced pluripotent stem cells to identify how CEP290 mutations cause retinal degeneration, and show an antisense approach can correct disease-associated phenotypes. PMID:27257755

  19. Multi-Disciplinary, Multi-Fidelity Discrete Data Transfer Using Degenerate Geometry Forms

    NASA Technical Reports Server (NTRS)

    Olson, Erik D.

    2016-01-01

    In a typical multi-fidelity design process, different levels of geometric abstraction are used for different analysis methods, and transitioning from one phase of design to the next often requires a complete re-creation of the geometry. To maintain consistency between lower-order and higher-order analysis results, Vehicle Sketch Pad (OpenVSP) recently introduced the ability to generate and export several degenerate forms of the geometry, representing the type of abstraction required to perform low- to medium-order analysis for a range of aeronautical disciplines. In this research, the functionality of these degenerate models was extended, so that in addition to serving as repositories for the geometric information that is required as input to an analysis, the degenerate models can also store the results of that analysis mapped back onto the geometric nodes. At the same time, the results are also mapped indirectly onto the nodes of lower-order degenerate models using a process called aggregation, and onto higher-order models using a process called disaggregation. The mapped analysis results are available for use by any subsequent analysis in an integrated design and analysis process. A simple multi-fidelity analysis process for a single-aisle subsonic transport aircraft is used as an example case to demonstrate the value of the approach.

  20. Germ cell degeneration in high-temperature treated pufferfish, Takifugu rubripes.

    PubMed

    Lee, K H; Yamaguchi, A; Rashid, H; Kadomura, K; Yasumoto, S; Matsuyama, M

    2009-01-01

    Exogenous factors such as temperature, social behavior, and salinity play a crucial role during the critical sensitive period of sex differentiation in many vertebrates. In fishes, amphibians, and reptiles temperature treatment is known to induce all-male (or female) individuals, and genes related to sex differentiation have been studied. The Japanese pufferfish, Takifugu rubripes, possesses the most compact genome among vertebrates and has immense potential for studies focusing on comparative genome analysis. In this study, we describe gonadal morphology and vasa (germ cell marker) and dmrt1 (Sertoli cell marker) expression on a molecular level in relation to the development of temperature-treated pufferfish. To investigate the relationship between temperature and gonadal development, pufferfish were exposed to high-temperature conditions (32 degrees C) during early gonadal development. Morphological observations showed that this high-temperature treatment did not influence sexual differentiation as determined by ovarian cavity characteristics; however, high-temperature treatment induces gonadal degeneration that is devoid of germ cells. RT-PCR results revealed no vasa expression within germ cell-degenerated gonads. In situ hybridization results showed that dmrt1 was expressed in somatic cells of germ cell-degenerated ovaries. These results suggest that high-temperature treatment during early gonadal development induces germ cell degeneration and masculinization of ovarian somatic cells in pufferfish.

  1. Aberrant protein trafficking in retinal degenerations: The initial phase of retinal remodeling.

    PubMed

    Bales, Katie L; Gross, Alecia K

    2016-09-01

    Retinal trafficking proteins are involved in molecular assemblies that govern protein transport, orchestrate cellular events involved in cilia formation, regulate signal transduction, autophagy and endocytic trafficking, all of which if not properly controlled initiate retinal degeneration. Improper function and or trafficking of these proteins and molecular networks they are involved in cause a detrimental cascade of neural retinal remodeling due to cell death, resulting as devastating blinding diseases. A universal finding in retinal degenerative diseases is the profound detection of retinal remodeling, occurring as a phased modification of neural retinal function and structure, which begins at the molecular level. Retinal remodeling instigated by aberrant trafficking of proteins encompasses many forms of retinal degenerations, such as the diverse forms of retinitis pigmentosa (RP) and disorders that resemble RP through mutations in the rhodopsin gene, retinal ciliopathies, and some forms of glaucoma and age-related macular degeneration (AMD). As a large majority of genes associated with these different retinopathies are overlapping, it is imperative to understand their underlying molecular mechanisms. This review will discuss some of the most recent discoveries in vertebrate retinal remodeling and retinal degenerations caused by protein mistrafficking. PMID:26632497

  2. Axon Degeneration Gated by Retrograde Activation of Somatic Pro-apoptotic Signaling.

    PubMed

    Simon, David J; Pitts, Jason; Hertz, Nicholas T; Yang, Jing; Yamagishi, Yuya; Olsen, Olav; Tešić Mark, Milica; Molina, Henrik; Tessier-Lavigne, Marc

    2016-02-25

    During development, sensory axons compete for limiting neurotrophic support, and local neurotrophin insufficiency triggers caspase-dependent axon degeneration. The signaling driving axon degeneration upon local deprivation is proposed to reside within axons. Our results instead support a model in which, despite the apoptotic machinery being present in axons, the cell body is an active participant in gating axonal caspase activation and axon degeneration. Loss of trophic support in axons initiates retrograde activation of a somatic pro-apoptotic pathway, which, in turn, is required for distal axon degeneration via an anterograde pro-degenerative factor. At a molecular level, the cell body is the convergence point of two signaling pathways whose integrated action drives upregulation of pro-apoptotic Puma, which, unexpectedly, is confined to the cell body. Puma then overcomes inhibition by pro-survival Bcl-xL and Bcl-w and initiates the anterograde pro-degenerative program, highlighting the role of the cell body as an arbiter of large-scale axon removal.

  3. Transneuronal Degeneration of Thalamic Nuclei following Middle Cerebral Artery Occlusion in Rats

    PubMed Central

    2016-01-01

    Objective. Postinfarction transneuronal degeneration refers to secondary neuronal death that occurs within a few days to weeks following the disruption of input or output to synapsed neurons sustaining ischemic insults. The thalamus receives its blood supply from the posterior circulation; however, infarctions of the middle cerebral arterial may cause secondary transneuronal degeneration in the thalamus. In this study, we presented the areas of ischemia and associated transneuronal degeneration following MCAo in a rat model. Materials and Methods. Eighteen 12-week-old male Sprague-Dawley rats were randomly assigned to receive middle cerebral artery occlusion surgery for 1, 7, and 14 days. Cerebral atrophy was assessed by 2,3,5-triphenyltetrazolium hydrochloride staining. Postural reflex and open field tests were performed prior to animal sacrifice to assess the effects of occlusion on behavior. Results. Myelin loss was observed at the lesion site following ischemia. Gliosis was also observed in thalamic regions 14 days following occlusion. Differential degrees of increased vascular endothelial growth factor expression were observed at each stage of infarction. Increases in myelin basic protein levels were also observed in the 14-day group. Conclusion. The present rat model of ischemia provides evidence of transneuronal degeneration within the first 14 days of occlusion. The observed changes in protein expression may be associated with self-repair mechanisms in the damaged brain. PMID:27597962

  4. Axon Degeneration Gated by Retrograde Activation of Somatic Pro-apoptotic Signaling.

    PubMed

    Simon, David J; Pitts, Jason; Hertz, Nicholas T; Yang, Jing; Yamagishi, Yuya; Olsen, Olav; Tešić Mark, Milica; Molina, Henrik; Tessier-Lavigne, Marc

    2016-02-25

    During development, sensory axons compete for limiting neurotrophic support, and local neurotrophin insufficiency triggers caspase-dependent axon degeneration. The signaling driving axon degeneration upon local deprivation is proposed to reside within axons. Our results instead support a model in which, despite the apoptotic machinery being present in axons, the cell body is an active participant in gating axonal caspase activation and axon degeneration. Loss of trophic support in axons initiates retrograde activation of a somatic pro-apoptotic pathway, which, in turn, is required for distal axon degeneration via an anterograde pro-degenerative factor. At a molecular level, the cell body is the convergence point of two signaling pathways whose integrated action drives upregulation of pro-apoptotic Puma, which, unexpectedly, is confined to the cell body. Puma then overcomes inhibition by pro-survival Bcl-xL and Bcl-w and initiates the anterograde pro-degenerative program, highlighting the role of the cell body as an arbiter of large-scale axon removal. PMID:26898330

  5. Transneuronal Degeneration of Thalamic Nuclei following Middle Cerebral Artery Occlusion in Rats.

    PubMed

    Chang, Shu-Jen; Cherng, Juin-Hong; Wang, Ding-Han; Yu, Shu-Ping; Liou, Nien-Hsien; Hsu, Ming-Lun

    2016-01-01

    Objective. Postinfarction transneuronal degeneration refers to secondary neuronal death that occurs within a few days to weeks following the disruption of input or output to synapsed neurons sustaining ischemic insults. The thalamus receives its blood supply from the posterior circulation; however, infarctions of the middle cerebral arterial may cause secondary transneuronal degeneration in the thalamus. In this study, we presented the areas of ischemia and associated transneuronal degeneration following MCAo in a rat model. Materials and Methods. Eighteen 12-week-old male Sprague-Dawley rats were randomly assigned to receive middle cerebral artery occlusion surgery for 1, 7, and 14 days. Cerebral atrophy was assessed by 2,3,5-triphenyltetrazolium hydrochloride staining. Postural reflex and open field tests were performed prior to animal sacrifice to assess the effects of occlusion on behavior. Results. Myelin loss was observed at the lesion site following ischemia. Gliosis was also observed in thalamic regions 14 days following occlusion. Differential degrees of increased vascular endothelial growth factor expression were observed at each stage of infarction. Increases in myelin basic protein levels were also observed in the 14-day group. Conclusion. The present rat model of ischemia provides evidence of transneuronal degeneration within the first 14 days of occlusion. The observed changes in protein expression may be associated with self-repair mechanisms in the damaged brain. PMID:27597962

  6. Anomalous skin effects in a weakly magnetized degenerate electron plasma

    SciTech Connect

    Abbas, G. Sarfraz, M.; Shah, H. A.

    2014-09-15

    Fully relativistic analysis of anomalous skin effects for parallel propagating waves in a weakly magnetized degenerate electron plasma is presented and a graphical comparison is made with the results obtained using relativistic Maxwellian distribution function [G. Abbas, M. F. Bashir, and G. Murtaza, Phys. Plasmas 18, 102115 (2011)]. It is found that the penetration depth for R- and L-waves for degenerate case is qualitatively small in comparison with the Maxwellian plasma case. The quantitative reduction due to weak magnetic field in the skin depth in R-wave for degenerate plasma is large as compared to the non-degenerate one. By ignoring the ambient magnetic field, previous results for degenerate field free case are salvaged [A. F. Alexandrov, A. S. Bogdankevich, and A. A. Rukhadze, Principles of Plasma Electrodynamics (Springer-Verlag, Berlin/Heidelberg, 1984), p. 90].

  7. Anomalous skin effects in a weakly magnetized degenerate electron plasma

    NASA Astrophysics Data System (ADS)

    Abbas, G.; Sarfraz, M.; Shah, H. A.

    2014-09-01

    Fully relativistic analysis of anomalous skin effects for parallel propagating waves in a weakly magnetized degenerate electron plasma is presented and a graphical comparison is made with the results obtained using relativistic Maxwellian distribution function [G. Abbas, M. F. Bashir, and G. Murtaza, Phys. Plasmas 18, 102115 (2011)]. It is found that the penetration depth for R- and L-waves for degenerate case is qualitatively small in comparison with the Maxwellian plasma case. The quantitative reduction due to weak magnetic field in the skin depth in R-wave for degenerate plasma is large as compared to the non-degenerate one. By ignoring the ambient magnetic field, previous results for degenerate field free case are salvaged [A. F. Alexandrov, A. S. Bogdankevich, and A. A. Rukhadze, Principles of Plasma Electrodynamics (Springer-Verlag, Berlin/Heidelberg, 1984), p. 90].

  8. Ius Chasma Tributary Valleys and Adjacent Plains

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This image covers valley tributaries of Ius Chasma, as well as the plains adjacent to the valleys. Ius Chasma is one of several canyons that make up the Valles Marineris canyon system. Valles Marineris likely formed by extension associated with the growth of the large volcanoes and topographic high of Tharsis to the northwest. As the ground was pulled apart, large and deep gaps resulted in the valleys seen in the top and bottom of this HiRISE image. Ice that was once in the ground could have also melted to create additional removal of material in the formation of the valleys. HiRISE is able to see the rocks along the walls of both these valleys and also impact craters in the image. Rock layers that appear lower down in elevation appear rougher and are shedding boulders. Near the top of the walls and also seen in patches along the smooth plains are brighter layers. These brighter layers are not shedding boulders so they must represent a different kind of rock formed in a different kind of environment than those further down the walls. Because they are highest in elevation, the bright layers are youngest in age. HiRISE is able to see dozens of the bright layers, which are perhaps only a meter in thickness. Darker sand dunes and ripples cover most of the plains and fill the floors of impact craters.

    Image PSP_001351_1715 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on November 9, 2006. The complete image is centered at -8.3 degrees latitude, 275.4 degrees East longitude. The range to the target site was 254.3 km (158.9 miles). At this distance the image scale ranges from 25.4 cm/pixel (with 1 x 1 binning) to 101.8 cm/pixel (with 4 x 4 binning). The image shown here has been map-projected to 25 cm/pixel and north is up. The image was taken at a local Mars time of 3:32 PM and the scene is illuminated from the west with a solar incidence angle of 59 degrees, thus the sun was about

  9. Learning Non-Adjacent Regularities at Age 0 ; 7

    ERIC Educational Resources Information Center

    Gervain, Judit; Werker, Janet F.

    2013-01-01

    One important mechanism suggested to underlie the acquisition of grammar is rule learning. Indeed, infants aged 0 ; 7 are able to learn rules based on simple identity relations (adjacent repetitions, ABB: "wo fe fe" and non-adjacent repetitions, ABA: "wo fe wo", respectively; Marcus et al., 1999). One unexplored issue is…

  10. View of north side from exterior stairs of adjacent building, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of north side from exterior stairs of adjacent building, bottom cut off by fringed buildings, view facing south-southwest - U.S. Naval Base, Pearl Harbor, Industrial X-Ray Building, Off Sixth Street, adjacent to and south of Facility No. 11, Pearl City, Honolulu County, HI

  11. Delayed Acquisition of Non-Adjacent Vocalic Distributional Regularities

    ERIC Educational Resources Information Center

    Gonzalez-Gomez, Nayeli; Nazzi, Thierry

    2016-01-01

    The ability to compute non-adjacent regularities is key in the acquisition of a new language. In the domain of phonology/phonotactics, sensitivity to non-adjacent regularities between consonants has been found to appear between 7 and 10 months. The present study focuses on the emergence of a posterior-anterior (PA) bias, a regularity involving two…

  12. Distinguishing epigenetic features of preneoplastic testis tissues adjacent to seminomas and nonseminomas

    PubMed Central

    Skvortsova, Yulia V.; Zinovyeva, Marina V.; Stukacheva, Elena A.; Klimov, Alexey; Tryakin, Alexey A.; Azhikina, Tatyana L.

    2016-01-01

    PIWI pathway proteins are expressed during spermatogenesis where they play a key role in germ cell development. Epigenetic loss of PIWI proteins expression was previously demonstrated in testicular germ cell tumors (TGCTs), implying their involvement in TGCT development. In this work, apart from studying only normal testis and TGCT samples, we also analyzed an intermediate stage, i.e. preneoplastic testis tissues adjacent to TGCTs. Importantly, in this study, we minimized the contribution of patient-to-patient heterogeneity by using matched preneoplastic/TGCT samples. Surprisingly, expression of germ cell marker DDX4 suggests that spermatogenesis is retained in premalignant testis tissues adjacent to nonseminoma, but not those adjacent to seminoma. Moreover, this pattern is followed by expression of PIWI pathway genes, which impacts one of their functions: DNA methylation level over LINE-1 promoters is higher in preneoplastic testis tissues adjacent to nonseminomas than those adjacent to seminomas. This finding might imply distinct routes for development of the two types of TGCTs and could be used as a novel diagnostic marker, possibly, noninvasively. Finally, we studied the role of CpG island methylation in expression of PIWI genes in patient samples and using in vitro experiments in cell line models: a more complex interrelation between DNA methylation and expression of the corresponding genes was revealed. PMID:26843623

  13. Lumbar Disc Degenerative Disease: Disc Degeneration Symptoms and Magnetic Resonance Image Findings

    PubMed Central

    Saleem, Shafaq; Rehmani, Muhammad Asim Khan; Raees, Aisha; Alvi, Arsalan Ahmad; Ashraf, Junaid

    2013-01-01

    Study Design Cross sectional and observational. Purpose To evaluate the different aspects of lumbar disc degenerative disc disease and relate them with magnetic resonance image (MRI) findings and symptoms. Overview of Literature Lumbar disc degenerative disease has now been proven as the most common cause of low back pain throughout the world. It may present as disc herniation, lumbar spinal stenosis, facet joint arthropathy or any combination. Presenting symptoms of lumbar disc degeneration are lower back pain and sciatica which may be aggravated by standing, walking, bending, straining and coughing. Methods This study was conducted from January 2012 to June 2012. Study was conducted on the diagnosed patients of lumbar disc degeneration. Diagnostic criteria were based upon abnormal findings in MRI. Patients with prior back surgery, spine fractures, sacroiliac arthritis, metabolic bone disease, spinal infection, rheumatoid arthritis, active malignancy, and pregnancy were excluded. Results During the targeted months, 163 patients of lumbar disc degeneration with mean age of 43.92±11.76 years, came into Neurosurgery department. Disc degeneration was most commonly present at the level of L4/L5 105 (64.4%).Commonest types of disc degeneration were disc herniation 109 (66.9%) and lumbar spinal stenosis 37 (22.7%). Spondylolisthesis was commonly present at L5/S1 10 (6.1%) and associated mostly with lumbar spinal stenosis 7 (18.9%). Conclusions Results reported the frequent occurrence of lumbar disc degenerative disease in advance age. Research efforts should endeavor to reduce risk factors and improve the quality of life. PMID:24353850

  14. Hemoglobin-induced neuronal degeneration in the hippocampus after neonatal intraventricular hemorrhage.

    PubMed

    Garton, Thomas P; He, Yangdong; Garton, Hugh J L; Keep, Richard F; Xi, Guohua; Strahle, Jennifer M

    2016-03-15

    Neuronal degeneration following neonatal intraventricular hemorrhage (IVH) is incompletely understood. Understanding the mechanisms of degeneration and cell loss may point toward specific treatments to limit injury. We evaluated the role of hemoglobin (Hb) in cell death after intraventricular injection in neonatal rats. Hb was injected into the right lateral ventricle of post-natal day 7 rats. Rats exposed to anesthesia were used for controls. The CA-1 region of the hippocampus was analyzed via immunohistochemistry, hematoxylin and eosin (H&E) staining, Fluoro-Jade C staining, Western blots, and double-labeling stains. Compared to controls, intraventricular injection of Hb decreased hippocampal volume (27% decrease; p<0.05), induced neuronal loss (31% loss; p<0.01), and increased neuronal degeneration (2.7 fold increase; p<0.01), which were all significantly reduced with the iron chelator, deferoxamine. Hb upregulated p-JNK (1.8 fold increase; p<0.05) and increased expression of the Hb/haptoglobin endocytotic receptor CD163 in neurons in vivo and in vitro (cultured cortical neurons). Hb induced expression of the CD163 receptor, which co-localized with p-JNK in hippocampal neurons, suggesting a potential pathway by which Hb enters the neuron to result in cell death. There were no differences in neuronal loss or degenerating neurons in Hb-injected animals that developed hydrocephalus versus those that did not. Intraventricular injection of Hb causes hippocampal neuronal degeneration and cell loss and increases brain p-JNK levels. p-JNK co-localized with the Hb/haptoglobin receptor CD163, suggesting a novel pathway by which Hb enters the neuron after IVH to result in cell death. PMID:26772987

  15. Rpe65 as a modifier gene for inherited retinal degeneration

    PubMed Central

    Samardzija, M.; Wenzel, A.; Naash, M.; Remé, C. E.; Grimm, C.

    2009-01-01

    Light accelerates progression of retinal degeneration in many animal models of retinitis pigmentosa (RP). A sequence variant in the Rpe65 gene (Rpe65450Leu or Rpe65450Met) can act as a modulator of light-damage susceptibility in mice by influencing the kinetics of rhodopsin regeneration and thus by modulating the photon absorption. Depending on exposure duration and light intensity applied, white fluorescent light induces photoreceptor apoptosis and retinal degeneration in wild-type mice by the activation of one of two known molecular pathways. These pathways depend, respectively, on activation of the transcription factor c-Fos/AP-1 and on phototransduction activity. Here we tested Rpe65 as a genetic modifier for inherited retinal degeneration and analysed which degenerative pathway is activated in a transgenic mouse model of autosomal dominant RP. We show that retinal degeneration was reduced in mice expressing the Rpe65450Met variant and that these mice retained more visual pigment rhodopsin than did transgenic mice expressing the Rpe65450Leu variant. In addition, lack of phototransduction slowed retinal degeneration whereas ablation of c-Fos had no effect. We conclude that sequence variations in the Rpe65 gene can act as genetic modifiers in inherited retinal degeneration, presumably by regulating the daily rate of photon absorption through the modulation of rhodopsin regeneration kinetics. Increased absorption of photons and/or light sensitivity appear to accelerate retinal degeneration via an apoptotic cascade which involves phototransduction but not c-Fos. PMID:16519667

  16. Hydrologic Connection Between Geysers and Adjacent Thermal Pools, Two Examples: El Tatio, Chile and Yellowstone, USA

    NASA Astrophysics Data System (ADS)

    Munoz Saez, C.; Fauria, K.; Manga, M.; Hurwitz, S.; Namiki, A.

    2014-12-01

    Geyser eruption cycles can be influenced by adjacent and distant thermals sources, suggesting a hydraulic connection through permeable pathways. Diffusion of fluid pressure can be responsible for the communication between geysers. In this study we examine the processes linking two different geysers with adjacent thermal pools. The first was Vega Rinconada, located at El Tatio geyser field, Chile, where we measured temperature inside the conduit between the ground surface and a depth of seven meters, at one-meter intervals. The second was Lone Star Geyser in Yellowstone National Park, where we measured temperature of the overflow water at the base of the cone. Concurrently, we measured temperature and the water level in pools adjacent to both geysers. We found common elements in both geyser - pool systems: First, water temperature in both adjacent pools was below the boiling point and cooler than water in the geysers. Second, changes in pool water levels were correlated with eruptions of the geysers. During the quiescent period of the geysers, the water level increased in adjacent pools, while water level in the pools deceased during eruptions. Additionally, measurements inside of the conduit in Vega Rinconada Geyser showed that water temperature increased in the deepest part of the conduit during eruptions, while water temperature decreased in the shallow part of the geyser conduit (~1 to 2 m). These drops in temperature in the shallow conduit were coincident with the drop in water level in the adjacent pool. This suggests that after the initiation of an eruption, water may drain from the pool to the geyser. Furthermore, we observed a temperature drop of 3oC in the shallow conduit immediately preceding the end of an eruption. This suggests that flow from the pool to geyser contributes to eruption shut off. Our observations of geyser-pool systems indicate a hydrologic connection between the geysers and their adjacent pools. In the case of Vega Rinconada, cold water

  17. Animal models of age related macular degeneration

    PubMed Central

    Pennesi, Mark E.; Neuringer, Martha; Courtney, Robert J.

    2013-01-01

    Age related macular degeneration (AMD) is the leading cause of vision loss of those over the age of 65 in the industrialized world. The prevalence and need to develop effective treatments for AMD has lead to the development of multiple animal models. AMD is a complex and heterogeneous disease that involves the interaction of both genetic and environmental factors with the unique anatomy of the human macula. Models in mice, rats, rabbits, pigs and non-human primates have recreated many of the histological features of AMD and provided much insight into the underlying pathological mechanisms of this disease. In spite of the large number of models developed, no one model yet recapitulates all of the features of human AMD. However, these models have helped reveal the roles of chronic oxidative damage, inflammation and immune dysregulation, and lipid metabolism in the development of AMD. Models for induced choroidal neovascularization have served as the backbone for testing new therapies. This article will review the diversity of animal models that exist for AMD as well as their strengths and limitations. PMID:22705444

  18. Disruption in dopaminergic innervation during photoreceptor degeneration.

    PubMed

    Ivanova, Elena; Yee, Christopher W; Sagdullaev, Botir T

    2016-04-15

    Dopaminergic amacrine cells (DACs) release dopamine in response to light-driven synaptic inputs, and are critical to retinal light adaptation. Retinal degeneration (RD) compromises the light responsiveness of the retina and, subsequently, dopamine metabolism is impaired. As RD progresses, retinal neurons exhibit aberrant activity, driven by AII amacrine cells, a primary target of the retinal dopaminergic network. Surprisingly, DACs are an exception to this physiological change; DACs exhibit rhythmic activity in healthy retina, but do not burst in RD. The underlying mechanism of this divergent behavior is not known. It is also unclear whether RD leads to structural changes in DACs, impairing functional regulation of AII amacrine cells. Here we examine the anatomical details of DACs in three mouse models of human RD to determine how changes to the dopaminergic network may underlie physiological changes in RD. By using rd10, rd1, and rd1/C57 mice we were able to dissect the impacts of genetic background and the degenerative process on DAC structure in RD retina. We found that DACs density, soma size, and primary dendrite length are all significantly reduced. Using a novel adeno-associated virus-mediated technique to label AII amacrine cells in mouse retina, we observed diminished dopaminergic contacts to AII amacrine cells in RD mice. This was accompanied by changes to the components responsible for dopamine synthesis and release. Together, these data suggest that structural alterations of the retinal dopaminergic network underlie physiological changes during RD.

  19. Genetic Factors in Intervertebral Disc Degeneration

    PubMed Central

    Feng, Yi; Egan, Brian; Wang, Jinxi

    2016-01-01

    Low back pain (LBP) is a major cause of disability and imposes huge economic burdens on human society worldwide. Among many factors responsible for LBP, intervertebral disc degeneration (IDD) is the most common disorder and is a target for intervention. The etiology of IDD is complex and its mechanism is still not completely understood. Many factors such as aging, spine deformities and diseases, spine injuries, and genetic factors are involved in the pathogenesis of IDD. In this review, we will focus on the recent advances in studies on the most promising and extensively examined genetic factors associated with IDD in humans. A number of genetic defects have been correlated with structural and functional changes within the intervertebral disc (IVD), which may compromise the disc’s mechanical properties and metabolic activities. These genetic and proteomic studies have begun to shed light on the molecular basis of IDD, suggesting that genetic factors are important contributors to the onset and progression of IDD. By continuing to improve our understanding of the molecular mechanisms of IDD, specific early diagnosis and more effective treatments for this disabling disease will be possible in the future. PMID:27617275

  20. [Multiple system atrophy - synuclein and neuronal degeneration].

    PubMed

    Yoshida, Mari

    2011-11-01

    Multiple system atrophy (MSA) is a sporadic neurodegenerative disorder that encompasses olivopontocerebellar atrophy (OPCA), striatonigral degeneration (SND) and Shy-Drager syndrome (SDS). The histopathological hallmarks are α-synuclein (AS) positive glial cytoplasmic inclusions (GCIs) in oligodendroglias. AS aggregation is also found in glial nuclear inclusions (GNIs), neuronal cytoplasmic inclusions (NCIs), neuronal nuclear inclusions (NNIs) and dystrophic neurties. Reviewing the pathological features of 102 MSA cases, OPCA-type was relatively more frequent and SND-type was less frequent in Japanese MSA cases, which suggested different phenotypic pattern of MSA might exist between races, compared to the relatively high frequency of SND-type in western countries. In early stage of MSA, NNIs, NCIs and diffuse homogenous stain of AS in neuronal nuclei and cytoplasm were observed in various vulnerable lesions including the pontine nuclei, putamen, substantia nigra, locus ceruleus, inferior olivary nucleus, intermediolateral column of thoracic cord, lower motor neurons and cortical pyramidal neurons, in additions to GCIs. These findings indicated that the primary nonfibrillar and fibrillar AS aggregation also occurred in neurons. Therefore both the direct involvement of neurons themselves and the oligodendroglia-myelin-axon mechanism may synergistically accelerate the degenerative process of MSA. PMID:22277386

  1. Widespread cytoskeletal pathology characterizes corticobasal degeneration.

    PubMed Central

    Feany, M. B.; Dickson, D. W.

    1995-01-01

    Corticobasal degeneration (CBD) is a rare, progressive neurological disorder characterized by widespread neuronal and glial pathology. Using immunohistochemistry and laser confocal microscopy, we demonstrate that the nonamyloid cortical plaques of CBD are actually collections of abnormal tau in the distal processes of astrocytes. These glial cells express both vimentin and CD44, markers of astrocyte activation. Glial pathology also includes tau-positive cytoplasmic inclusions, here localized to Leu 7-expressing oligodendrocytes. In addition, a wide array of neuronal pathology is defined with tau-positive inclusions in multiple domains of a variety of cortical neurons. CBD thus exhibits widespread glial and neuronal cytoskeletal pathology, including a novel structure, the astrocytic plaque. CBD is a disease of generalized cytoskeletal disruption affecting several cell types and multiple domains of these cells. The further definition of CBD pathology refines the diagnosis and pathophysiological understanding of this unique disease and has important implications for other neurodegenerative diseases, like Alzheimer's disease, characterized by abnormal tau deposition. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:7778678

  2. Evidence for degenerate tetraploidy in bdelloid rotifers.

    PubMed

    Mark Welch, David B; Mark Welch, Jessica L; Meselson, Matthew

    2008-04-01

    Rotifers of class Bdelloidea have evolved for millions of years apparently without sexual reproduction. We have sequenced 45- to 70-kb regions surrounding the four copies of the hsp82 gene of the bdelloid rotifer Philodina roseola, each of which is on a separate chromosome. The four regions comprise two colinear gene-rich pairs with gene content, order, and orientation conserved within each pair. Only a minority of genes are common to both pairs, also in the same orientation and order, but separated by gene-rich segments present in only one or the other pair. The pattern is consistent with degenerate tetraploidy with numerous segmental deletions, some in one pair of colinear chromosomes and some in the other. Divergence in 1,000-bp windows varies along an alignment of a colinear pair, from zero to as much as 20% in a pattern consistent with gene conversion associated with recombinational repair of DNA double-strand breaks. Although pairs of colinear chromosomes are a characteristic of sexually reproducing diploids and polyploids, a quite different explanation for their presence in bdelloids is suggested by the recent finding that bdelloid rotifers can recover and resume reproduction after suffering hundreds of radiation-induced DNA double-strand breaks per oocyte nucleus. Because bdelloid primary oocytes are in G(1) and therefore lack sister chromatids, we propose that bdelloid colinear chromosome pairs are maintained as templates for the repair of DNA double-strand breaks caused by the frequent desiccation and rehydration characteristic of bdelloid habitats.

  3. Physics of Age Related Macular Degeneration

    NASA Astrophysics Data System (ADS)

    Family, Fereydoon

    2009-11-01

    Age-related macular degeneration (AMD) is the leading cause of blindness beyond the age of 50 years. The most common pathogenic mechanism that leads to AMD is choroidal neovascularization (CNV). CNV is produced by accumulation of residual material caused by aging of retinal pigment epithelium cells (RPE). The RPE is a phagocytic system that is essential for renewal of photoreceptors (rods and cones). With time, incompletely degraded membrane material builds up in the form of lipofuscin. Lipofuscin is made of free-radical-damaged protein and fat, which forms not only in AMD, but also Alzheimer's disease, and Parkinson's disease. The study of lipofuscin formation and growth is important, because of their association with cellular aging. In this talk I will discuss a model of non-equilibrium cluster growth that we have developed for studying the formation and growth of lipofuscin in AMD [K.I. Mazzitello, C.M. Arizmendi, Fereydoon Family, H. E. Grossniklaus, Physical Review E (2009)]. I will also present an overview of our theoretical and computational efforts in modeling some other aspects of the physics of AMD, including CNV and the breakdown of Bruch's membrane [Ongoing collaboration with Abbas Shirinifard and James A. Glazier, Biocomplexity Institute and Department of Physics, Indiana University, Y. Jiang, Los Alamos, and Hans E. Grossniklaus, Department of Ophthalmology, Emory University].

  4. Chronic nerve root entrapment: compression and degeneration

    NASA Astrophysics Data System (ADS)

    Vanhoestenberghe, A.

    2013-02-01

    Electrode mounts are being developed to improve electrical stimulation and recording. Some are tight-fitting, or even re-shape the nervous structure they interact with, for a more selective, fascicular, access. If these are to be successfully used chronically with human nerve roots, we need to know more about the possible damage caused by the long-term entrapment and possible compression of the roots following electrode implantation. As there are, to date, no such data published, this paper presents a review of the relevant literature on alternative causes of nerve root compression, and a discussion of the degeneration mechanisms observed. A chronic compression below 40 mmHg would not compromise the functionality of the root as far as electrical stimulation and recording applications are concerned. Additionally, any temporary increase in pressure, due for example to post-operative swelling, should be limited to 20 mmHg below the patient’s mean arterial pressure, with a maximum of 100 mmHg. Connective tissue growth may cause a slower, but sustained, pressure increase. Therefore, mounts large enough to accommodate the root initially without compressing it, or compliant, elastic, mounts, that may stretch to free a larger cross-sectional area in the weeks after implantation, are recommended.

  5. Mechanisms of age-related macular degeneration

    PubMed Central

    Ambati, Jayakrishna; Fowler, Benjamin J.

    2012-01-01

    Age-related macular degeneration (AMD), a progressive condition that is untreatable in up to 90% of patients, is a leading cause of blindness in the elderly worldwide. The two forms of AMD, wet and dry, are classified based on the presence or absence of blood vessels that have disruptively invaded the retina, respectively. A detailed understanding of the molecular mechanisms underlying wet AMD has led to several robust FDA-approved therapies. In contrast, there are not any approved treatments for dry AMD. In this review, we provide insight into the critical effector pathways that mediate each form of disease. The interplay of immune and vascular systems for wet AMD, and the proliferating interest in hunting for gene variants to explain AMD pathogenesis, are placed in the context of the latest clinical and experimental data. Emerging models of dry AMD pathogenesis are presented, with a focus on DICER1 deficit and the toxic accumulation of retinal debris. A recurring theme that spans most aspects of AMD pathogenesis is defective immune modulation in the classically immune-privileged ocular haven. Interestingly, the latest advances in AMD research highlight common molecular disease pathways with other common neurodegenerations. Finally, the therapeutic potential of intervening at known mechanisms of AMD pathogenesis is discussed. PMID:22794258

  6. Statistical physics of age related macular degeneration

    NASA Astrophysics Data System (ADS)

    Family, Fereydoon; Mazzitello, K. I.; Arizmendi, C. M.; Grossniklaus, H. E.

    Age-related macular degeneration (AMD) is the leading cause of blindness beyond the age of 50 years. The most common pathogenic mechanism that leads to AMD is choroidal neovascularization (CNV). CNV is produced by accumulation of residual material caused by aging of retinal pigment epithelium cells (RPE). The RPE is a phagocytic system that is essential for renewal of photoreceptors (rods and cones). With time, incompletely degraded membrane material builds up in the form of lipofuscin. Lipofuscin is made of free-radical-damaged protein and fat, which forms not only in AMD, but also Alzheimer disease and Parkinson disease. The study of lipofuscin formation and growth is important, because of their association with cellular aging. We introduce a model of non-equilibrium cluster growth and aggregation that we have developed for studying the formation and growth of lipofuscin in the aging RPE. Our results agree with a linear growth of the number of lipofuscin granules with age. We apply the dynamic scaling approach to our model and find excellent data collapse for the cluster size distribution. An unusual feature of our model is that while small particles are removed from the RPE the larger ones become fixed and grow by aggregation.

  7. The genetics of frontotemporal lobar degeneration.

    PubMed

    Rademakers, Rosa; Hutton, Mike

    2007-09-01

    The clinical disorders associated with frontotemporal lobar degeneration (FTLD) are increasingly recognized as an important cause of early-onset dementia. Patients usually present with progressive changes in personality, behavior, or language, progressing to general cognitive impairment and ultimately death. In the past decade, improved clinical and histopathologic characterization uncovered extensive heterogeneity, and multiple clinical and pathologic FTLD subtypes were defined. Simultaneously, the discovery of four causal FTLD genes emphasized the genetic complexity associated with FTLD. More recently, the field of FTLD has gained increased attention as a result of two major findings. First, mutations in the progranulin gene (PGRN) were recognized as a major cause of FTLD with ubiquitin-positive and tau-negative inclusions (FTLD-U), and subsequently the TAR DNA-binding protein-43 (TDP-43) was identified as a key protein within the ubiquitinated inclusions in FTLD-U and amyotrophic lateral sclerosis (ALS). In this report, we outline the progress made in the study of the genetic etiologies and neuropathologic substrates in FTLD.

  8. Clinical Experiences of Non-fusion Dynamic Stabilization Surgery for Adjacent Segmental Pathology after Lumbar Fusion

    PubMed Central

    Lee, Soo Eon; Kim, Hyun-Jib

    2016-01-01

    Background As an alternative to spinal fusion, non-fusion dynamic stabilization surgery has been developed, showing good clinical outcomes. In the present study, we introduce our surgical series, which involves non-fusion dynamic stabilization surgery for adjacent segment pathology (ASP) after lumbar fusion surgery. Methods Fifteen patients (13 female and 2 male, mean age of 62.1 years) who underwent dynamic stabilization surgery for symptomatic ASP were included and medical records, magnetic resonance images (MRI), and plain radiographs were retrospectively evaluated. Results Twelve of the 15 patients had the fusion segment at L4-5, and the most common segment affected by ASP was L3-4. The time interval between prior fusion and later non-fusion surgery was mean 67.0 months. The Visual Analog Scale and Oswestry Disability Index showed values of 7.4 and 58.5% before the non-fusion surgery and these values respectively declined to 4.2 and 41.3% postoperatively at 36 months (p=0.027 and p=0.018, respectively). During the mean 44.8 months of follow-up, medication of analgesics was also significantly reduced. The MRI grade for disc and central stenosis identified significant degeneration at L3-4, and similar disc degeneration from lateral radiographs was determined at L3-4 between before the prior fusion surgery and the later non-fusion surgery. After the non-fusion surgery, the L3-4 segment and the proximal segment of L2-3 were preserved in the disc, stenosis and facet joint whereas L1-2 showed disc degeneration on the last MRI (p=0.032). Five instances of radiologic ASP were identified, showing characteristic disc-space narrowing at the proximal segments of L1-2 and L2-3. However, no patient underwent additional surgery for ASP after non-fusion dynamic stabilization surgery. Conclusion The proposed non-fusion dynamic stabilization system could be an effective surgical treatment for elderly patients with symptomatic ASP after lumbar fusion. PMID:27162710

  9. Local reactivity descriptors from degenerate frontier molecular orbitals

    NASA Astrophysics Data System (ADS)

    Martínez, Jorge

    2009-08-01

    Conceptual Density Functional Theory (DFT) has proposed a set of local descriptors to measure the reactivity on specific sites of a molecule, as an example dual descriptor has been successfully used in analyzing interesting systems to understand their local reactivity, however under the frozen orbital approximation (FOA), it is defined from non-degenerate frontier molecular orbitals (FMOs). In this work, the degeneration is taken into account to propose approximated expressions to obtain the dual descriptor, nucleophilic and electrophilic Fukui functions in closed-shell systems. The proposed expressions have been tested on molecules presenting degenerate FMOs.

  10. Weakly dissipative solitons in dense relativistic-degenerate plasma

    NASA Astrophysics Data System (ADS)

    Ahmad, Saeed; Ata-ur-Rahman; Khan, S. A.

    2015-07-01

    We investigate the features of weakly nonlinear waves in a collisional dense plasma consisting of ultra-relativistic degenerate electrons and non-relativistic degenerate ions. In weak dissipation limit, the dynamics of low frequency nonlinear ion (solitary) wave is described by solving a damped Korteweg-deVries equation. The analytical and numerical analysis shows the existence of weakly dissipative solitons evolving with time. The characteristics of soliton evolution with plasma number density and slow ion-neutral collision rate are discussed with some detail. The relevance of the study with degenerate plasmas in ultra-dense astrophysical objects, particularly white dwarf stars is also pointed out.

  11. Late degeneration in rabbit tissues after irradiation by heavy ions

    NASA Technical Reports Server (NTRS)

    Lett, J. T.; Cox, A. B.; Keng, P. C.; Lee, A. C.; Su, C. M.; Bergtold, D. S.

    1980-01-01

    Results are presented for investigations of the late effects of heavy-ion irradiation on rabbit tissues which were undertaken to assess the hazards associated with the long-term exposure of humans to heavy ions in space during such activities as the construction of solar power stations or voyages to Mars. White rabbits approximately six weeks old were exposed to various doses of collimated beams of 400-MeV/n Ne ions, 570 MeV/n Ar ions and Co-60 gamma rays directed through both eyes, and the responses of the various tissues (hair follicles, skin, cornea, lens, retina, Harderian glands, bone and forebrain) were examined. Proliferating tissues are found to exhibit high damage levels in the early and late periods following irradiation, while terminally differentiating tissues repond to radiation most intensely in the late period, years after irradiation, with no intermediate recovery. The results obtained from rabbits are used to predict the occurrence of late tissue degeneration in the central nervous system, terminally differentiating systems and stem cells of humans one or more decades following exposure to radiation levels anticipated during long-duration space flights. The studies also indicate that tissues may be prematurely aged in the sense that tissue life spans may be shortened without the development of malignancies.

  12. Angiogenesis in the degeneration of the lumbar intervertebral disc

    PubMed Central

    David, Gh; Iencean, SM; Mohan, A

    2010-01-01

    The goal of the study is to show the histological and biochemical changes that indicate the angiogenesis of the intervertebral disc in lumbar intervertebral disc hernia and the existence of epidemiological correlations between these changes and the risk factors of lumbar intervertebral disc hernia, as well as the patient's quality of life (QOL). We have studied 50 patients aged between 18 and 73 years old, who have undergone lumbar intervertebral disc hernia surgery, making fibroblast growth factor and vascular endothelial growth factor level measurements, as elements in the process of appreciating the disc angiogenesis. Also, pre–surgery and post–surgery QOL has been measured, as well as the intensity of the pain syndrome. We have identified factors capable of stimulating vascular endothelial growth (VEGF, FGF–2) for the examined disc material, but histological examination did not show angiogenesis. The process of angiogenesis at the degenerated intervertebral disc level affects the patient's quality of life both pre and postoperatively, and may be a predictive factor for the post–operative results. Patients can prevent the appearance of angiogenesis type degenerative processes of the intervertebral disc by avoiding angiogenesis correlated factors (weight control, physical effort, and smoking). PMID:20968201

  13. Nutritional Risk Factors for Age-Related Macular Degeneration

    PubMed Central

    Ersoy, Lebriz; Lechanteur, Yara T.; Hoyng, Carel B.; Kirchhof, Bernd; den Hollander, Anneke I.

    2014-01-01

    Purpose. To evaluate the role of nutritional factors, serum lipids, and lipoproteins in late age-related macular degeneration (late AMD). Methods. Intake of red meat, fruit, fish, vegetables, and alcohol, smoking status, and body mass index (BMI) were ascertained questionnaire-based in 1147 late AMD cases and 1773 controls from the European Genetic Database. Serum levels of lipids and lipoproteins were determined. The relationship between nutritional factors and late AMD was assessed using logistic regression. Based on multivariate analysis, area-under-the-curve (AUC) was calculated by receiver-operating-characteristics (ROC). Results. In a multivariate analysis, besides age and smoking, obesity (odds ratio (OR): 1.44, P = 0.014) and red meat intake (daily: OR: 2.34, P = 8.22 × 10−6; 2–6x/week: OR: 1.67, P = 7.98 × 10−5) were identified as risk factors for developing late AMD. Fruit intake showed a protective effect (daily: OR: 0.52, P = 0.005; 2–6x/week: OR: 0.58, P = 0.035). Serum lipid and lipoprotein levels showed no significant association with late AMD. ROC for nutritional factors, smoking, age, and BMI revealed an AUC of 0.781. Conclusion. Red meat intake and obesity were independently associated with increased risk for late AMD, whereas fruit intake was protective. A better understanding of nutritional risk factors is necessary for the prevention of AMD. PMID:25101280

  14. Retinal degeneration in cats fed casein. I. Taurine deficiency.

    PubMed

    Schmidt, S Y; Berson, E L; Hayes, K C

    1976-01-01

    All cats fed a taurine-free casein diet for at least 23 weeks have shown granularity with a hyper-reflective white zone in the area centralis, nondetectable electroretinograms (ERG's), and structural changes indicating photoreceptor cell degeneration. The present study has demonstrated that cats fed this casein diet have a selective decrease in plasma and retinal taurine concentrations by five weeks; taurine levels were about 4 per cent of normal in plasma, and 60 per cent of normal in retina. After 10 weeks, taurine levels were 2 to 4 per cent of normal in plasma and reached a minimum of 20 to 30 per cent of normal in the retina. These biochemical changes occurred in association with a delay in the cone ERG implicit time at five weeks and reduced cone and rod ERG amplitudes at 10 weeks. During this period, retinal DNA content (as a measure of cell viability) and fundus appearance were normal. By 23 weeks, ERG's were nondetectable, retinal DNA content was reduced, and the fundus showed typical changes in the area centralis. These studies help to establish a biological role for taurine in maintaining photoreceptor cell function and viability in the cat.

  15. Degenerate Quasicrystal of Hard Triangular Bipyramids Stabilized by Entropic Forces

    NASA Astrophysics Data System (ADS)

    Haji-Akbari, Amir; Engel, Michael; Glotzer, Sharon

    2012-02-01

    The assembly of hard polyhedra into novel ordered structures has recently received much attention. Here we focus on triangular bipyramids (TBPs)- i.e. dimers of hard tetrahedra- which pack densely in a simple triclinic crystal with two particles per unit cell [1]. This packing is referred to as the TBP crystal. We show that hard TBPs do not form this densest packing in simulation. Instead, they assemble into a different, far more complicated structure, a dodecagonal quasicrystal, which, in the level of monomers, is identical to the quasicrystal recently discovered in the hard tetrahedron system [2], but the way that tetrahedra pair into TBPs in the nearest neighbor network is random, making it the first degenerate quasicrystal reported in the literature [3]. This notion of degeneracy is in the level of decorating individual tiles and is different from the degeneracy of a quasiperiodic random tiling arising from phason flips [4]. The (3.4.3^2.4) approximant of the quasicrystal is shown to be more stable than the TBP crystal at densities below 79.7%.[4pt] [1] Chen ER, Engel M, Sharon SC, Disc. Comp. Geom. 44:253 (2010).[0pt] [2] Haji-Akbari A, Engel M, et al. Nature 462:773 (2009).[0pt] [3] Haji-Akbari A, Engel M, Glotzer SC, arXiv:1106.5561 [PRL, in press].[0pt] [4] Elser V, PRL 54: 1730 (1985)

  16. MDC-Analyzer: a novel degenerate primer design tool for the construction of intelligent mutagenesis libraries with contiguous sites.

    PubMed

    Tang, Lixia; Wang, Xiong; Ru, Beibei; Sun, Hengfei; Huang, Jian; Gao, Hui

    2014-06-01

    Recent computational and bioinformatics advances have enabled the efficient creation of novel biocatalysts by reducing amino acid variability at hot spot regions. To further expand the utility of this strategy, we present here a tool called Multi-site Degenerate Codon Analyzer (MDC-Analyzer) for the automated design of intelligent mutagenesis libraries that can completely cover user-defined randomized sequences, especially when multiple contiguous and/or adjacent sites are targeted. By initially defining an objective function, the possible optimal degenerate PCR primer profiles could be automatically explored using the heuristic approach of Greedy Best-First-Search. Compared to the previously developed DC-Analyzer, MDC-Analyzer allows for the existence of a small amount of undesired sequences as a tradeoff between the number of degenerate primers and the encoded library size while still providing all the benefits of DC-Analyzer with the ability to randomize multiple contiguous sites. MDC-Analyzer was validated using a series of randomly generated mutation schemes and experimental case studies on the evolution of halohydrin dehalogenase, which proved that the MDC methodology is more efficient than other methods and is particularly well-suited to exploring the sequence space of proteins using data-driven protein engineering strategies.

  17. Glycolysis in Patients with Age-Related Macular Degeneration

    PubMed Central

    Yokosako, Kanako; Mimura, Tatsuya; Funatsu, Hideharu; Noma, Hidetaka; Goto, Mari; Kamei, Yuko; Kondo, Aki; Matsubara, Masao

    2014-01-01

    Purpose: Retinal adenosine triphosphate is mainly produced via glycolysis, so inhibition of glycolysis may promote the onset and progression of age-related macular degeneration (AMD). When glycolysis is inhibited, pyruvate is metabolized by lactic acid fermentation instead of entering the mitochondrial tricarboxylic acid (TCA) cycle. We measured urinary pyruvate and lactate levels in patients with AMD. Methods: Eight patients with typical AMD (tAMD group) and 9 patients with polypoidal choroidal vasculopathy (PCV group) were enrolled. Urinary levels of pyruvate, lactate, α-hydroxybutyrate, and β-hydroxybutyrate were measured in all patients. Results: The mean urinary levels of pyruvate and lactate were 8.0 ± 2.8 and 7.5 ± 8.3 μg/mg creatinine (reference values: 0.5-6.6 and 0.0-1.6), respectively, with the mean increase over the reference value being 83.6 ± 51.1% and 426.5 ± 527.8%, respectively. In 12 patients (70.6%), the lactate/pyruvate ratio was above the reference range. Urinary levels of α-hydroxybutyrate and β-hydroxybutyrate were decreased by -31.9 ± 15.2% and -33.1 ± 17.5% compared with the mean reference values. There were no significant differences of any of these glycolysis metabolites between the tAMD and PCV groups. Multivariate analysis revealed that none of the variables tested, including patient background factors (age, hypertension, diabetes, hyperlipidemia, cerebrovascular disease, alcohol, smoking, visual acuity, and AMD phenotype), were significantly associated with the lactate/pyruvate ratio. Conclusion: A high lactate/pyruvate ratio is a well-known marker of mitochondrial impairment, and it indicates poor oxidative function in AMD. Our results suggest that increased lactate levels may be implicated in the pathogenesis of AMD. PMID:25191529

  18. Atlantoaxial dislocation adjacent to kyphotic deformity in a case of adult Larsen syndrome.

    PubMed

    Sahoo, Sushanta K; Deepak, Arsikere N; Salunke, Pravin

    2016-01-01

    Kyphotic deformity is often seen in Larsen syndrome. However, its progress in adults is not clear. The adjacent level compression in these patients adds to the difficulty regarding the level that needs to be operated. A 56-year-old male presented with neck pain and spastic quadriplegia. Radiology showed kyphotic deformity (sequelae of Larsen syndrome) with atlantoaxial dislocation. Cord compression was apparent at both levels but careful evaluation showed C1-2 level compression and some compression below the kyphotic deformity. The kyphotic spine was already fused and the canal diameter was adequate. The adjacent level C1-2 was fused and he improved dramatically. Correction of long-standing kyphotic deformity may not be necessary, as it unlikely to progress because of its tendency to fuse naturally. Rather, the adjacent levels are likely to compress the cord due to excessive stress. A proper clinical history and a thorough radiological examination help the surgeon to make an appropriate decision. PMID:27217658

  19. Inhibition of de novo ceramide biosynthesis by FTY720 protects rat retina from light-induced degeneration[S

    PubMed Central

    Chen, Hui; Tran, Julie-Thu A.; Eckerd, Annette; Huynh, Tuan-Phat; Elliott, Michael H.; Brush, Richard S.; Mandal, Nawajes A.

    2013-01-01

    Light-induced retinal degeneration (LIRD) in albino rats causes apoptotic photoreceptor cell death. Ceramide is a second messenger for apoptosis. We tested whether increases in ceramide mediate photoreceptor apoptosis in LIRD and if inhibition of ceramide synthesis protects the retina. Sprague-Dawley rats were exposed to 2,700 lux white light for 6 h, and the retinal levels of ceramide and its intermediary metabolites were measured by GC-MS or electrospray ionization tandem mass spectrometry. Enzymes of the de novo biosynthetic and sphingomyelinase pathways of ceramide generation were assayed, and gene expression was measured. The dosage and temporal effect of the ceramide synthase inhibitor FTY720 on the LIRD retina were measured by histological and functional analyses. Retinal ceramide levels increased coincident with the increase of dihydroceramide at various time points after light stress. Light stress in retina induces ceramide generation predominantly through the de novo pathway, which was prevented by systemic administration of FTY720 (10 mg/kg) leading to the protection of retinal structure and function. The neuroprotection of FTY720 was independent of its immunosuppressive action. We conclude that ceramide increase by de novo biosynthesis mediates photoreceptor apoptosis in the LIRD model and that inhibition of ceramide production protects the retina against light stress. PMID:23468130

  20. Lock 4 View east of lock wall and adjacent ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Lock 4 - View east of lock wall and adjacent roadway built atop tow path. The gate pocket can be seen at center. - Savannah & Ogeechee Barge Canal, Between Ogeechee & Savannah Rivers, Savannah, Chatham County, GA

  1. 14. Charles Acey Cobb standing adjacent to the fish screen ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Charles Acey Cobb standing adjacent to the fish screen he designed and installed in the Congdon Canal, facing southeast. Photo dates ca. late 1920's. - Congdon Canal, Fish Screen, Naches River, Yakima, Yakima County, WA

  2. 3. View of north side of house facing from adjacent ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. View of north side of house facing from adjacent vacant property. Original wood lap siding and trim is covered by aluminum siding. Recessed side porch is in middle. - 645 South Eighteenth Street (House), Louisville, Jefferson County, KY

  3. View from water showing south facade and adjacent boat slips ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View from water showing south facade and adjacent boat slips (Facility Nos. S375 & S376) - U.S. Naval Base, Pearl Harbor, Boat House, Hornet Avenue at Independence Street, Pearl City, Honolulu County, HI

  4. OBLIQUE OF SOUTHWEST END AND SOUTHEAST SIDE, WITH ADJACENT FACILITY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OBLIQUE OF SOUTHWEST END AND SOUTHEAST SIDE, WITH ADJACENT FACILITY 391 IN THE FOREGROUND. - U.S. Naval Base, Pearl Harbor, Joint Intelligence Center, Makalapa Drive in Makalapa Administration Area, Pearl City, Honolulu County, HI

  5. Interior building details of Building A, dungeon cell adjacent to ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior building details of Building A, dungeon cell adjacent to northwest cell: granite and brick threshold, poured concrete floors, plastered finished walls, vaulted veiling; northwesterly view - San Quentin State Prison, Building 22, Point San Quentin, San Quentin, Marin County, CA

  6. View of viaduct, looking SE from roof of adjacent parking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of viaduct, looking SE from roof of adjacent parking garage. - Mulberry Street Viaduct, Spanning Paxton Creek & Cameron Street (State Route 230) at Mulberry Street (State Route 3012), Harrisburg, Dauphin County, PA

  7. Cement Leakage into Adjacent Vertebral Body Following Percutaneous Vertebroplasty

    PubMed Central

    Park, Jae Hoo; Kim, Hyeun Sung

    2016-01-01

    Percutaneous vertebroplasty (PV) is a minimally invasive procedure for osteoporotic vertebral compression fractures that fail to respond to conventional conservative treatment. It significantly improves intolerable back pain within hours, and has a low complication rate. Although rare, PV is not free of complications, most of which are directly related to cement leakage. Because of its association with new adjacent fracture, the importance of cement leakage into the adjacent disc space is paramount. Here, we report an interesting case of cement leakage into the adjacent upper vertebral body as well as disc space following PV. To the best of our knowledge, there has been no report of cement leakage into the adjacent vertebral body following PV. This rare case is presented along with a review of the literature. PMID:27437018

  8. 2. DETAIL OF CONTROL GATE ADJACENT TO LIFT LOCK NO. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. DETAIL OF CONTROL GATE ADJACENT TO LIFT LOCK NO. 7; THIS CONTROL GATE IS A 1980s RECONSTRUCTION. - Illinois & Michigan Canal, Lift Lock No. 7 & Control Gate, East side of DuPage River, Channahon, Will County, IL

  9. 33. HISTORIC PLAQUE MARKING WHERE JOHNSTON DIED, ADJACENT TO PATHWAY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. HISTORIC PLAQUE MARKING WHERE JOHNSTON DIED, ADJACENT TO PATHWAY WITH CONCRETE CULVERT LEADING NORTH OUT OF RAVINE TOWARD JOHNSTON MEMORIAL SITE. VIEW NW. - Shiloh National Military Park Tour Roads, Shiloh, Hardin County, TN

  10. VIEW OF LAMP FIXTURE (EXTERIOR) ADJACENT TO ENTRANCE AT SOUTHWEST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF LAMP FIXTURE (EXTERIOR) ADJACENT TO ENTRANCE AT SOUTHWEST CORNER OF BUILDING 23, FACING NORTH - Roosevelt Base, Auditorium-Gymnasium, West Virginia Street between Richardson & Reeves Avenues, Long Beach, Los Angeles County, CA

  11. VIEW OF NORTHERN AND EASTERN SIDES FROM PARKING LOT ADJACENT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF NORTHERN AND EASTERN SIDES FROM PARKING LOT ADJACENT TO BUILDING 199 (POLICE STATION) - U.S. Naval Base, Pearl Harbor, Post Office, Avenue A near Eleventh Avenue, Pearl City, Honolulu County, HI

  12. 73. PASSAGE ADJACENT TO ROOM 232, EAST WING, SECOND FLOOR, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    73. PASSAGE ADJACENT TO ROOM 232, EAST WING, SECOND FLOOR, LOOKING WEST BY NORTHWEST, SHOWING EASTERNMOST ARCH OF FORMER GREAT HALL NORTH ARCADE - Smithsonian Institution Building, 1000 Jefferson Drive, between Ninth & Twelfth Streets, Southwest, Washington, District of Columbia, DC

  13. 28. TOP VIEW OF CIRCUIT BREAKER ADJACENT TO BRIDGE, CATENARY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. TOP VIEW OF CIRCUIT BREAKER ADJACENT TO BRIDGE, CATENARY ANCHOR BRIDGE 310, COS COB POWER PLANT - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

  14. 1. A BRICK AND CONCRETE FAN HOUSING ADJACENT TO ONE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. A BRICK AND CONCRETE FAN HOUSING ADJACENT TO ONE OF THE ADIT OPENINGS (VIEW TO THE NORTH). - Foster Gulch Mine, Fan Housing, Bear Creek 1 mile Southwest of Town of Bear Creek, Red Lodge, Carbon County, MT

  15. GENERAL VIEW OF WAREHOUSE ADJACENT TO BATCH PLANT, LOOKING NORTHWEST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GENERAL VIEW OF WAREHOUSE ADJACENT TO BATCH PLANT, LOOKING NORTHWEST FROM DREY STREET PLANT, INSIDE WELCOME WALL - Chambers Window Glass Company, Warehouse & Shipping, North of Drey (Nineteenth) Street, West of Constitution Boulevard, Arnold, Westmoreland County, PA

  16. 10. SLATE PATIO ADJACENT TO SOUTH PORCH OF HOUSE, FROM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. SLATE PATIO ADJACENT TO SOUTH PORCH OF HOUSE, FROM SOUTHEAST CORNER OF REAR PORCH. SHED IS VISIBLE IN BACKGROUND. - Butt Valley Dam, Gate Tender's House, Butt Valley Reservoir Road, Caribou, Plumas County, CA

  17. Detail of fire alarm boxes located adjacent to the entrance ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of fire alarm boxes located adjacent to the entrance of the northwest wing - Mare Island Naval Shipyard, Guard House & Barracks, Railroad Avenue near Eighteenth Street, Vallejo, Solano County, CA

  18. Detail exterior view looking north showing piping system adjacent to ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail exterior view looking north showing piping system adjacent to engine house. Gas cooling system is on far right. - Burnsville Natural Gas Pumping Station, Saratoga Avenue between Little Kanawha River & C&O Railroad line, Burnsville, Braxton County, WV

  19. 1. Ninth Street (west) facade. Adjacent on the north is ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Ninth Street (west) facade. Adjacent on the north is the 9th Street facade of 816 E Street. Both buildings were originally one property. - Riley Building, Rendezvous Adult Magazines & Films, 437 Ninth Street, Northwest, Washington, District of Columbia, DC

  20. 2. THREEQUARTER VIEW FROM ADJACENT ACCESS ROAD SHOWING THREE SPANS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. THREE-QUARTER VIEW FROM ADJACENT ACCESS ROAD SHOWING THREE SPANS AND NORTHWEST APPROACH SPANS, LOOKING SOUTHEAST - Red River Bridge, Spanning Red River at U.S. Highway 82, Garland, Miller County, AR

  1. 31. VAL, DETAIL OF LOADING PLATFORM ADJACENT TO LAUNCHER BRIDGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. VAL, DETAIL OF LOADING PLATFORM ADJACENT TO LAUNCHER BRIDGE LOOKING WEST. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  2. Basement, room 23, looking southwest into two adjacent offices with ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Basement, room 23, looking southwest into two adjacent offices with soundproof walls and pedestal flooring - March Air Force Base, Strategic Air Command, Combat Operations Center, 5220 Riverside Drive, Moreno Valley, Riverside County, CA

  3. 52. EASTSIDE PLANT: GENERAL VIEW OF GOVERNOR ADJACENT TO GENERATOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    52. EASTSIDE PLANT: GENERAL VIEW OF GOVERNOR ADJACENT TO GENERATOR - American Falls Water, Power & Light Company, Island Power Plant, Snake River, below American Falls Dam, American Falls, Power County, ID

  4. 7. August, 1970 9 ORANGE STREET, ADJACENT TO UNITARIAN CHURCH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. August, 1970 9 ORANGE STREET, ADJACENT TO UNITARIAN CHURCH (NOT IN STUDY AREA) - Orange & Union Streets Neighborhood Study, 8-31 Orange Street, 9-21 Union Street & Stone Alley, Nantucket, Nantucket County, MA

  5. Brick incinerator structure located adjacent to "motor courts." This example ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Brick incinerator structure located adjacent to "motor courts." This example is located between Buildings 26 and 27. Facing northeast - Harbor Hills Housing Project, 26607 Western Avenue, Lomita, Los Angeles County, CA

  6. An Unusual Case of Extensive Lattice Degeneration and Retinal Detachment

    PubMed Central

    Sarma, Saurabh Kumar; Basaiawmoit, Jennifer V.

    2016-01-01

    Lattice degeneration of the retina is not infrequently encountered on a dilated retinal examination and many of them do not need any intervention. We report a case of atypical lattice degeneration variant with peripheral retinal detachment. An asymptomatic 35-year-old lady with minimal refractive error was found to have extensive lattice degeneration, peripheral retinal detachment and fibrotic changes peripherally with elevation of retinal vessels on dilated retinal examination. There were also areas of white without pressure, chorioretinal scarring and retinal breaks. All the changes were limited to beyond the equator but were found to span 360 degrees. She was treated with barrage laser all around to prevent extension of the retinal detachment posteriorly. She remained stable till her latest follow-up two years after the barrage laser. This case is reported for its rarity with a discussion of the probable differential diagnoses. To the best of our knowledge, this is the first report of such findings in lattice degeneration.

  7. Hypertrophic olivary degeneration and cerebrovascular disease: movement in a triangle.

    PubMed

    Santos, Ana Filipa; Rocha, Sofia; Varanda, Sara; Pinho, João; Rodrigues, Margarida; Ramalho Fontes, João; Soares-Fernandes, João; Ferreira, Carla

    2015-02-01

    Hypertrophic olivary degeneration is a rare kind of trans-synaptic degeneration that occurs after lesions of the dentatorubro-olivary pathway. The lesions, commonly unilateral, may result from hemorrhage due to vascular malformation, trauma, surgical intervention or hypertension, tumor, or ischemia. Bilateral cases are extremely rare. This condition is classically associated with development of palatal tremor, but clinical manifestations can include other involuntary movements. We describe 2 cases: unilateral hypertrophic olivary degeneration in a 60-year-old man with contralateral athetosis and neurologic worsening developing several years after a pontine hemorrhage and bilateral hypertrophic olivary degeneration in a 77-year-old woman with development of palatal tremor, probably secondary to pontine ischemic lesions (small vessel disease).

  8. [Progress on the degeneration mechanism of cave fishes' eyes].

    PubMed

    Gu, Xian; Ning, Tiao; Xiao, Heng

    2012-08-01

    Attempts to understand the degeneration of the eyes in cave fish has largely been explained by either various extents of gradual degeneration, ranging from partial to total loss, observed in various species or by acceleration of loss caused by dark environments. However, neither the theory of biological evolution developed by Charles Darwin nor the neutral theory of molecular evolution formulated by Kimura Motoo adequately explains these phenomena. Recent trends in utilizing multidisciplinary research, however, have yielded better results, helping reveal a more complex picture of the mechanisms of degeneration. Here, we summarize the current progress of the research via morphology and anatomy, development biology, animal behavior science and molecular genetics, and offer some perspectives on the ongoing research into the development and degeneration of eyes in cave fish.

  9. Microglial phagocytosis of living photoreceptors contributes to inherited retinal degeneration.

    PubMed

    Zhao, Lian; Zabel, Matthew K; Wang, Xu; Ma, Wenxin; Shah, Parth; Fariss, Robert N; Qian, Haohua; Parkhurst, Christopher N; Gan, Wen-Biao; Wong, Wai T

    2015-07-02

    Retinitis pigmentosa, caused predominantly by mutations in photoreceptor genes, currently lacks comprehensive treatment. We discover that retinal microglia contribute non-cell autonomously to rod photoreceptor degeneration by primary phagocytosis of living rods. Using rd10 mice, we found that the initiation of rod degeneration is accompanied by early infiltration of microglia, upregulation of phagocytic molecules in microglia, and presentation of "eat-me" signals on mutated rods. On live-cell imaging, infiltrating microglia interact dynamically with photoreceptors via motile processes and engage in rapid phagocytic engulfment of non-apoptotic rods. Microglial contribution to rod demise is evidenced by morphological and functional amelioration of photoreceptor degeneration following genetic ablation of retinal microglia. Molecular inhibition of microglial phagocytosis using the vitronectin receptor antagonist cRGD also improved morphological and functional parameters of degeneration. Our findings highlight primary microglial phagocytosis as a contributing mechanism underlying cell death in retinitis pigmentosa and implicate microglia as a potential cellular target for therapy.

  10. Distinct optical properties of relativistically degenerate matter

    SciTech Connect

    Akbari-Moghanjoughi, M.

    2014-06-15

    In this paper, we use the collisional quantum magnetohydrodynamic (CQMHD) model to derive the transverse dielectric function of a relativistically degenerate electron fluid and investigate various optical parameters, such as the complex refractive index, the reflection and absorption coefficients, the skin-depth and optical conductivity. In this model we take into accounts effects of many parameters such as the atomic-number of the constituent ions, the electron exchange, electron diffraction effect and the electron-ion collisions. Study of the optical parameters in the solid-density, the warm-dense-matter, the big-planetary core, and the compact star number-density regimes reveals that there are distinct differences between optical characteristics of the latter and the former cases due to the fundamental effects of the relativistic degeneracy and other quantum mechanisms. It is found that in the relativistic degeneracy plasma regime, such as found in white-dwarfs and neutron star crusts, matter possess a much sharper and well-defined step-like reflection edge beyond the x-ray electromagnetic spectrum, including some part of gamma-ray frequencies. It is also remarked that the magnetic field intensity only significantly affects the plasma reflectivity in the lower number-density regime, rather than the high density limit. Current investigation confirms the profound effect of relativistic degeneracy on optical characteristics of matter and can provide an important plasma diagnostic tool for studying the physical processes within the wide scope of quantum plasma regimes be it the solid-density, inertial-confined, or astrophysical compact stars.

  11. Microbial Source Tracking in Adjacent Karst Springs

    PubMed Central

    Vaizel-Ohayon, Dalit; Rom, Meir; Guttman, Joseph; Berger, Diego; Kravitz, Valeria; Pilo, Shlomo; Huberman, Zohar; Kashi, Yechezkel; Rorman, Efrat

    2015-01-01

    Modern man-made environments, including urban, agricultural, and industrial environments, have complex ecological interactions among themselves and with the natural surroundings. Microbial source tracking (MST) offers advanced tools to resolve the host source of fecal contamination beyond indicator monitoring. This study was intended to assess karst spring susceptibilities to different fecal sources using MST quantitative PCR (qPCR) assays targeting human, bovine, and swine markers. It involved a dual-time monitoring frame: (i) monthly throughout the calendar year and (ii) daily during a rainfall event. Data integration was taken from both monthly and daily MST profile monitoring and improved identification of spring susceptibility to host fecal contamination; three springs located in close geographic proximity revealed different MST profiles. The Giach spring showed moderate fluctuations of MST marker quantities amid wet and dry samplings, while the Zuf spring had the highest rise of the GenBac3 marker during the wet event, which was mirrored in other markers as well. The revelation of human fecal contamination during the dry season not connected to incidents of raining leachates suggests a continuous and direct exposure to septic systems. Pigpens were identified in the watersheds of Zuf, Shefa, and Giach springs and on the border of the Gaaton spring watershed. Their impact was correlated with partial detection of the Pig-2-Bac marker in Gaaton spring, which was lower than detection levels in all three of the other springs. Ruminant and swine markers were detected intermittently, and their contamination potential during the wet samplings was exposed. These results emphasized the importance of sampling design to utilize the MST approach to delineate subtleties of fecal contamination in the environment. PMID:26002893

  12. Microbial Source Tracking in Adjacent Karst Springs.

    PubMed

    Ohad, Shoshanit; Vaizel-Ohayon, Dalit; Rom, Meir; Guttman, Joseph; Berger, Diego; Kravitz, Valeria; Pilo, Shlomo; Huberman, Zohar; Kashi, Yechezkel; Rorman, Efrat

    2015-08-01

    Modern man-made environments, including urban, agricultural, and industrial environments, have complex ecological interactions among themselves and with the natural surroundings. Microbial source tracking (MST) offers advanced tools to resolve the host source of fecal contamination beyond indicator monitoring. This study was intended to assess karst spring susceptibilities to different fecal sources using MST quantitative PCR (qPCR) assays targeting human, bovine, and swine markers. It involved a dual-time monitoring frame: (i) monthly throughout the calendar year and (ii) daily during a rainfall event. Data integration was taken from both monthly and daily MST profile monitoring and improved identification of spring susceptibility to host fecal contamination; three springs located in close geographic proximity revealed different MST profiles. The Giach spring showed moderate fluctuations of MST marker quantities amid wet and dry samplings, while the Zuf spring had the highest rise of the GenBac3 marker during the wet event, which was mirrored in other markers as well. The revelation of human fecal contamination during the dry season not connected to incidents of raining leachates suggests a continuous and direct exposure to septic systems. Pigpens were identified in the watersheds of Zuf, Shefa, and Giach springs and on the border of the Gaaton spring watershed. Their impact was correlated with partial detection of the Pig-2-Bac marker in Gaaton spring, which was lower than detection levels in all three of the other springs. Ruminant and swine markers were detected intermittently, and their contamination potential during the wet samplings was exposed. These results emphasized the importance of sampling design to utilize the MST approach to delineate subtleties of fecal contamination in the environment.

  13. Single-degenerate Type Ia Supernovae Are Preferentially Overluminous

    NASA Astrophysics Data System (ADS)

    Fisher, Robert; Jumper, Kevin

    2015-06-01

    Recent observational and theoretical progress has favored merging and helium-accreting sub-Chandrasekhar mass white dwarfs (WDs) in the double-degenerate and the double-detonation channels, respectively, as the most promising progenitors of normal Type Ia supernovae (SNe Ia). Thus the fate of rapidly accreting Chandrasekhar mass WDs in the single-degenerate channel remains more mysterious then ever. In this paper, we clarify the nature of ignition in Chandrasekhar-mass single-degenerate SNe Ia by analytically deriving the existence of a characteristic length scale which establishes a transition from central ignitions to buoyancy-driven ignitions. Using this criterion, combined with data from three-dimensional simulations of convection and ignition, we demonstrate that the overwhelming majority of ignition events within Chandrasekhar-mass WDs in the single-degenerate channel are buoyancy-driven, and consequently lack a vigorous deflagration phase. We thus infer that single-degenerate SNe Ia are generally expected to lead to overluminous 1991T-like SNe Ia events. We establish that the rates predicted from both the population of supersoft X-ray sources (SSSs) and binary population synthesis models of the single-degenerate channel are broadly consistent with the observed rates of overluminous SNe Ia, and suggest that the population of SSSs are the dominant stellar progenitors of SNe 1991T-like events. We further demonstrate that the single-degenerate channel contribution to the normal and failed 2002cx-like rates is not likely to exceed 1% of the total SNe Ia rate. We conclude with a range of observational tests of overluminous SNe Ia which will either support or strongly constrain the single-degenerate scenario.

  14. SINGLE-DEGENERATE TYPE Ia SUPERNOVAE ARE PREFERENTIALLY OVERLUMINOUS

    SciTech Connect

    Fisher, Robert; Jumper, Kevin

    2015-06-01

    Recent observational and theoretical progress has favored merging and helium-accreting sub-Chandrasekhar mass white dwarfs (WDs) in the double-degenerate and the double-detonation channels, respectively, as the most promising progenitors of normal Type Ia supernovae (SNe Ia). Thus the fate of rapidly accreting Chandrasekhar mass WDs in the single-degenerate channel remains more mysterious then ever. In this paper, we clarify the nature of ignition in Chandrasekhar-mass single-degenerate SNe Ia by analytically deriving the existence of a characteristic length scale which establishes a transition from central ignitions to buoyancy-driven ignitions. Using this criterion, combined with data from three-dimensional simulations of convection and ignition, we demonstrate that the overwhelming majority of ignition events within Chandrasekhar-mass WDs in the single-degenerate channel are buoyancy-driven, and consequently lack a vigorous deflagration phase. We thus infer that single-degenerate SNe Ia are generally expected to lead to overluminous 1991T-like SNe Ia events. We establish that the rates predicted from both the population of supersoft X-ray sources (SSSs) and binary population synthesis models of the single-degenerate channel are broadly consistent with the observed rates of overluminous SNe Ia, and suggest that the population of SSSs are the dominant stellar progenitors of SNe 1991T-like events. We further demonstrate that the single-degenerate channel contribution to the normal and failed 2002cx-like rates is not likely to exceed 1% of the total SNe Ia rate. We conclude with a range of observational tests of overluminous SNe Ia which will either support or strongly constrain the single-degenerate scenario.

  15. Stochastic partial differential equations with unbounded and degenerate coefficients

    NASA Astrophysics Data System (ADS)

    Zhang, Xicheng

    In this article, using DiPerna-Lions theory (DiPerna and Lions, 1989) [1], we investigate linear second order stochastic partial differential equations with unbounded and degenerate non-smooth coefficients, and obtain several conditions for existence and uniqueness. Moreover, we also prove the L-integrability and a general maximal principle for generalized solutions of SPDEs. As applications, we study nonlinear filtering problem and also obtain the existence and uniqueness of generalized solutions for a degenerate nonlinear SPDE.

  16. Mechanism of All-trans-retinal Toxicity with Implications for Stargardt Disease and Age-related Macular Degeneration*

    PubMed Central

    Chen, Yu; Okano, Kiichiro; Maeda, Tadao; Chauhan, Vishal; Golczak, Marcin; Maeda, Akiko; Palczewski, Krzysztof

    2012-01-01

    Compromised clearance of all-trans-retinal (atRAL), a component of the retinoid cycle, increases the susceptibility of mouse retina to acute light-induced photoreceptor degeneration. Abca4−/−Rdh8−/− mice featuring defective atRAL clearance were used to examine the one or more underlying molecular mechanisms, because exposure to intense light causes severe photoreceptor degeneration in these animals. Here we report that bright light exposure of Abca4−/−Rdh8−/− mice increased atRAL levels in the retina that induced rapid NADPH oxidase-mediated overproduction of intracellular reactive oxygen species (ROS). Moreover, such ROS generation was inhibited by blocking phospholipase C and inositol 1,4,5-trisphosphate-induced Ca2+ release, indicating that activation occurs upstream of NADPH oxidase-mediated ROS generation. Because multiple upstream G protein-coupled receptors can activate phospholipase C, we then tested the effects of antagonists of serotonin 2A (5-HT2AR) and M3-muscarinic (M3R) receptors and found they both protected Abca4−/−Rdh8−/− mouse retinas from light-induced degeneration. Thus, a cascade of signaling events appears to mediate the toxicity of atRAL in light-induced photoreceptor degeneration of Abca4−/−Rdh8−/− mice. A similar mechanism may be operative in human Stargardt disease and age-related macular degeneration. PMID:22184108

  17. Spiral ganglion degeneration and hearing loss as a consequence of satellite cell death in saposin B-deficient mice.

    PubMed

    Akil, Omar; Sun, Ying; Vijayakumar, Sarath; Zhang, Wujuan; Ku, Tiffany; Lee, Chi-Kyou; Jones, Sherri; Grabowski, Gregory A; Lustig, Lawrence R

    2015-02-18

    Saposin B (Sap B) is an essential activator protein for arylsulfatase A in the hydrolysis of sulfatide, a lipid component of myelin. To study Sap B's role in hearing and balance, a Sap B-deficient (B(-/-)) mouse was evaluated. At both light and electron microscopy (EM) levels, inclusion body accumulation was seen in satellite cells surrounding spiral ganglion (SG) neurons from postnatal month 1 onward, progressing into large vacuoles preceding satellite cell degeneration, and followed by SG degeneration. EM also revealed reduced or absent myelin sheaths in SG neurons from postnatal month 8 onwards. Hearing loss was initially seen at postnatal month 6 and progressed thereafter for frequency-specific stimuli, whereas click responses became abnormal from postnatal month 13 onward. The progressive hearing loss correlated with the accumulation of inclusion bodies in the satellite cells and their subsequent degeneration. Outer hair cell numbers and efferent function measures (distortion product otoacoustic emissions and contralateral suppression) were normal in the B(-/-) mice throughout this period. Alcian blue staining of SGs demonstrated that these inclusion bodies corresponded to sulfatide accumulation. In contrast, changes in the vestibular system were much milder, but caused severe physiologic deficits. These results demonstrate that loss of Sap B function leads to progressive sulfatide accumulation in satellite cells surrounding the SG neurons, leading to satellite cell degeneration and subsequent SG degeneration with a resultant loss of hearing. Relative sparing of the efferent auditory and vestibular neurons suggests that alternate glycosphingolipid metabolic pathways predominate in these other systems.

  18. Quantitative metabolomics of photoreceptor degeneration and the effects of stem cell-derived retinal pigment epithelium transplantation.

    PubMed

    Wang, Junhua; Westenskow, Peter D; Fang, Mingliang; Friedlander, Martin; Siuzdak, Gary

    2016-10-28

    Photoreceptor degeneration is characteristic of vision-threatening diseases including age-related macular degeneration. Photoreceptors are metabolically demanding cells in the retina, but specific details about their metabolic behaviours are unresolved. The quantitative metabolomics of retinal degeneration could provide valuable insights and inform future therapies. Here, we determined the metabolomic 'fingerprint' of healthy and dystrophic retinas in rat models using optimized metabolite extraction techniques. A number of classes of metabolites were consistently dysregulated during degeneration: vitamin A analogues, fatty acid amides, long-chain polyunsaturated fatty acids, acyl carnitines and several phospholipid species. For the first time, a distinct temporal trend of several important metabolites including DHA (4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoic acid), all-trans-retinal and its toxic end-product N-retinyl-N-retinylidene-ethanolamine were observed between healthy and dystrophic retinas. In this study, metabolomics was further used to determine the temporal effects of the therapeutic intervention of grafting stem cell-derived retinal pigment epithelium (RPE) in dystrophic retinas, which significantly prevented photoreceptor atrophy in our previous studies. The result revealed that lipid levels such as phosphatidylethanolamine in eyes were restored in those animals receiving the RPE grafts. In conclusion, this study provides insight into the metabolomics of retinal degeneration, and further understanding of the efficacy of RPE transplantation.This article is part of the themed issue 'Quantitative mass spectrometry'. PMID:27644974

  19. Prolonged Prevention of Retinal Degeneration with Retinylamine Loaded Nanoparticles

    PubMed Central

    Puntel, Anthony; Maeda, Akiko; Golczak, Marcin; Gao, Song-Qi; Yu, Guanping; Palczewski, Krzysztof; Lu, Zheng-Rong

    2015-01-01

    Retinal degeneration impairs the vision of millions in all age groups worldwide. Increasing evidence suggests that the etiology of many retinal degenerative diseases is associated with impairment in biochemical reactions involved in the visual cycle, a metabolic pathway responsible for regeneration of the visual chromophore (11-cis-retinal). Inefficient clearance of toxic retinoid metabolites, especially all-trans-retinal, is considered responsible for photoreceptor cytotoxicity. Primary amines, including retinylamine, are effective in lowing the concentration of all-trans-retinal within the retina and thus prevent retina degeneration in mouse models of human retinopathies. Here we achieved prolonged prevention of retinal degeneration by controlled delivery of retinylamine to the eye from polylactic acid nanoparticles in Abca4−/−Rdh8−/− (DKO) mice, an animal model of Stargardt disease/age-related macular degeneration. Subcutaneous administration of the nanoparticles containing retinylamine provided a constant supply of the drug to the eye for about a week and resulted in effective prolonged prevention of light-induced retinal degeneration in DKO mice. Retinylamine nanoparticles hold promise for prolonged prophylactic treatment of human retinal degenerative diseases, including Stargardt disease and age-related macular degeneration. PMID:25617130

  20. Spatially coordinated kinase signaling regulates local axon degeneration.

    PubMed

    Chen, Mark; Maloney, Janice A; Kallop, Dara Y; Atwal, Jasvinder K; Tam, Stephen J; Baer, Kristin; Kissel, Holger; Kaminker, Joshua S; Lewcock, Joseph W; Weimer, Robby M; Watts, Ryan J

    2012-09-26

    In addition to being a hallmark of neurodegenerative disease, axon degeneration is used during development of the nervous system to prune unwanted connections. In development, axon degeneration is tightly regulated both temporally and spatially. Here, we provide evidence that degeneration cues are transduced through various kinase pathways functioning in spatially distinct compartments to regulate axon degeneration. Intriguingly, glycogen synthase kinase-3 (GSK3) acts centrally, likely modulating gene expression in the cell body to regulate distally restricted axon degeneration. Through a combination of genetic and pharmacological manipulations, including the generation of an analog-sensitive kinase allele mutant mouse for GSK3β, we show that the β isoform of GSK3, not the α isoform, is essential for developmental axon pruning in vitro and in vivo. Additionally, we identify the dleu2/mir15a/16-1 cluster, previously characterized as a regulator of B-cell proliferation, and the transcription factor tbx6, as likely downstream effectors of GSK3β in axon degeneration.

  1. X-linked recessive atrophic macular degeneration from RPGR mutation.

    PubMed

    Ayyagari, Radha; Demirci, F Yesim; Liu, Jiafan; Bingham, Eve L; Stringham, Heather; Kakuk, Laura E; Boehnke, Michael; Gorin, Michael B; Richards, Julia E; Sieving, Paul A

    2002-08-01

    We mapped a new X-linked recessive atrophic macular degeneration locus to Xp21.1-p11.4 and show allelic involvement of the gene RPGR, which normally causes severe peripheral retinal degeneration leading to global blindness. Ten affected males whom we examined had primarily macular atrophy causing progressive loss of visual acuity with minimal peripheral visual impairment. One additional male showed extensive macular degeneration plus peripheral loss of retinal pigment epithelium and choriocapillaries. Full-field electroretinograms (ERGs) showed normal cone and rod responses in some affected males despite advanced macular degeneration, emphasizing the dissociation of atrophic macular degeneration from generalized cone degenerations, including X-linked cone dystrophy (COD1). The RPGR gene nonsense mutation G-->T at open reading frame (ORF)15+1164 cosegregated with the disease and may create a donor splice site. Identification of an RPGR mutation in atrophic maculardegeneration expands the phenotypic range associated with this gene and provides a new tool for the dissection of the relationship between clinically different retinal pathologies.

  2. Arachidonic Acid Derivatives and Their Role in Peripheral Nerve Degeneration and Regeneration

    PubMed Central

    Camara-Lemarroy, Carlos Rodrigo; Gonzalez-Moreno, Emmanuel Irineo; Guzman-de la Garza, Francisco Javier; Fernandez-Garza, Nancy Esthela

    2012-01-01

    After peripheral nerve injury, a process of axonal degradation, debris clearance, and subsequent regeneration is initiated by complex local signaling, called Wallerian degeneration (WD). This process is in part mediated by neuroglia as well as infiltrating inflammatory cells and regulated by inflammatory mediators such as cytokines, chemokines, and the activation of transcription factors also related to the inflammatory response. Part of this neuroimmune signaling is mediated by the innate immune system, including arachidonic acid (AA) derivatives such as prostaglandins and leukotrienes. The enzymes responsible for their production, cyclooxygenases and lipooxygenases, also participate in nerve degeneration and regeneration. The interactions between signals for nerve regeneration and neuroinflammation go all the way down to the molecular level. In this paper, we discuss the role that AA derivatives might play during WD and nerve regeneration, and the therapeutic possibilities that arise. PMID:22997489

  3. Topological semimetals with triply degenerate nodal points in θ -phase tantalum nitride

    NASA Astrophysics Data System (ADS)

    Weng, Hongming; Fang, Chen; Fang, Zhong; Dai, Xi

    2016-06-01

    Using first-principles calculation and symmetry analysis, we propose that θ -TaN is a topological semimetal having a new type of point nodes, i.e., triply degenerate nodal points. Each node is a band crossing between degenerate and nondegenerate bands along the high-symmetry line in the Brillouin zone, and is protected by crystalline symmetries. Such new type of nodes will always generate singular touching points between different Fermi surfaces and three-dimensional spin texture around them. Breaking the crystalline symmetry by external magnetic field or strain leads to various topological phases. By studying the Landau levels under a small field along the c axis, we demonstrate that the system has a new quantum anomaly that we call "helical anomaly.'

  4. Block of gap junctions eliminates aberrant activity and restores light responses during retinal degeneration.

    PubMed

    Toychiev, Abduqodir H; Ivanova, Elena; Yee, Christopher W; Sagdullaev, Botir T

    2013-08-28

    Retinal degeneration leads to progressive photoreceptor cell death, resulting in vision loss. Subsequently, inner retinal neurons develop aberrant synaptic activity, compounding visual impairment. In retinal ganglion cells, light responses driven by surviving photoreceptors are obscured by elevated levels of aberrant spiking activity. Here, we demonstrate in rd10 mice that targeting disruptive neuronal circuitry with a gap junction antagonist can significantly reduce excessive spiking. This treatment increases the sensitivity of the degenerated retina to light stimuli driven by residual photoreceptors. Additionally, this enhances signal transmission from inner retinal neurons to ganglion cells, potentially allowing the retinal network to preserve the fidelity of signals either from prosthetic electronic devices, or from cells optogenetically modified to transduce light. Thus, targeting maladaptive changes to the retina allows for treatments to use existing neuronal tissue to restore light sensitivity, and to augment existing strategies to replace lost photoreceptors. PMID:23986234

  5. Block of Gap Junctions Eliminates Aberrant Activity and Restores Light Responses during Retinal Degeneration

    PubMed Central

    Toychiev, Abduqodir H.; Ivanova, Elena; Yee, Christopher W.

    2013-01-01

    Retinal degeneration leads to progressive photoreceptor cell death, resulting in vision loss. Subsequently, inner retinal neurons develop aberrant synaptic activity, compounding visual impairment. In retinal ganglion cells, light responses driven by surviving photoreceptors are obscured by elevated levels of aberrant spiking activity. Here, we demonstrate in rd10 mice that targeting disruptive neuronal circuitry with a gap junction antagonist can significantly reduce excessive spiking. This treatment increases the sensitivity of the degenerated retina to light stimuli driven by residual photoreceptors. Additionally, this enhances signal transmission from inner retinal neurons to ganglion cells, potentially allowing the retinal network to preserve the fidelity of signals either from prosthetic electronic devices, or from cells optogenetically modified to transduce light. Thus, targeting maladaptive changes to the retina allows for treatments to use existing neuronal tissue to restore light sensitivity, and to augment existing strategies to replace lost photoreceptors. PMID:23986234

  6. MyD88-dependent Toll-like receptor 4 signal pathway in intervertebral disc degeneration

    PubMed Central

    Qin, Chuqiang; Zhang, Bo; Zhang, Liang; Zhang, Zhi; Wang, Le; Tang, Long; Li, Shuangqing; Yang, Yixi; Yang, Fuguo; Zhang, Ping; Yang, Bo

    2016-01-01

    Lower back pain (LBP) is a common and remitting problem. One of the primary causes of LBP is thought to be degeneration of the intervertebral disc (IVD). The aim of the present study was to investigate the role of the myeloid differentiation primary-response protein 88 (MyD88)-dependent Toll-like receptor 4 (TLR4) signal pathway in the mechanism of IVD degeneration. IVD nucleus pulposus cells isolated and cultured from the lumbar vertebrae of Wistar rats were stimulated by various doses of lipopolysaccharide (LPS; 0.1, 1, 10 and 100 µg/ml) to simulate IVD degeneration. Cells were rinsed and cultured in serum-free Dulbecco's modified Eagle's medium/F12. Reverse transcription-quantitative polymerase chain reaction was used to determine the levels of TLR4, MyD88, tumor necrosis factor α (TNFα), and interleukin-1β (IL-1β) mRNA expression after 1, 3, 6, 9 and 12 h of incubation. Additionally, western blot and enzyme-linked immunosorbent assay analyses were used to determine the levels of TLR4, MyD88, TNFα, and IL-1β protein expression after 24, 48 and 72 h of incubation. The levels of TLR4, MyD88, TNFα and IL-1β mRNA all increased in the cells stimulated by 10 µg/ml LPS at 3, 6 and 9 h (all P<0.001). Furthermore, the levels of TLR4, MyD88, TNFα and IL-1β protein all increased at 24, 48 and 72 h (all P<0.001). Additionally, the mRNA and protein levels of TLR4, MyD88, TNFα and IL-1β increased significantly in the cells stimulated by 1, 10 and 100 µg/ml LPS compared with the control group, and reached a peak in the 10 µg/ml LPS group (all P<0.001). These results suggest that the MyD88-dependent TLR4 signal pathway is a target pathway in IVD degeneration. This pathway is time phase- and dose-dependent, and when activated can lead to the release of inflammatory factors that participate in IVD degeneration. PMID:27446251

  7. Influence of anti-VEGF about cardiovascular biomarkers in age related macular degeneration.

    PubMed

    Manresa, N; Mulero, J; Losada, M; Zafrilla, P

    2015-02-01

    Systemic VEGF inhibition disrupts endothelial homeostasis and accelerates the atherogenesis, suggesting that these events contribute to the clinical cardiovascular adverse events of VEGF-inhibiting therapies. The objective of the current study was to analyze the effect of anti-VEGF therapy on cardiovascular risk factors in patients with exudative age related macular degeneration. A total of 73 patients with exudative age related macular degeneration (without previous anti-VEGF therapy) were treated with two anti-VEGF: Ranibizumab and Pegaptanib sodium. The follow up was 6 months. The following parameters were determined before and after treatment: homocysteine, lipids (total cholesterol, triglycerides, HDL-c, LDL-c), C-Reactive Protein and fibrinogen. There were not statistically significant differences in parameters studied before and after treatment with both Pegaptanib sodium and Ranibizumab, except C-Reactive Protein. Of all patients analyzed, only 3 of them have initially C-Reactive Protein levels above normal levels and after antiangiogenic therapy, there was a significant increase in C-Reactive Protein. We have not found results in our study who to suspect that treatment with anti-VEGF in the patients with exudative age related macular degeneration increases cardiovascular risk predictors. However, after therapy was increased the CRP and fibrinogen may mean that anti-VEGF contribute an alteration of endothelial homeostasis in exudative AMD.

  8. Multiple Independent Oscillatory Networks in the Degenerating Retina.

    PubMed

    Euler, Thomas; Schubert, Timm

    2015-01-01

    During neuronal degenerative diseases, microcircuits undergo severe structural alterations, leading to remodeling of synaptic connectivity. This can be particularly well observed in the retina, where photoreceptor degeneration triggers rewiring of connections in the retina's first synaptic layer (e.g., Strettoi et al., 2003; Haq et al., 2014), while the synaptic organization of inner retinal circuits appears to be little affected (O'Brien et al., 2014; Figures 1A,B). Remodeling of (outer) retinal circuits and diminishing light-driven activity due to the loss of functional photoreceptors lead to spontaneous activity that can be observed at different retinal levels (Figure 1C), including the retinal ganglion cells, which display rhythmic spiking activity in the degenerative retina (Margolis et al., 2008; Stasheff, 2008; Menzler and Zeck, 2011; Stasheff et al., 2011). Two networks have been suggested to drive the oscillatory activity in the degenerating retina: a network of remnant cone photoreceptors, rod bipolar cells (RBCs) and horizontal cells in the outer retina (Haq et al., 2014), and the AII amacrine cell-cone bipolar cell network in the inner retina (Borowska et al., 2011). Notably, spontaneous rhythmic activity in the inner retinal network can be triggered in the absence of synaptic remodeling in the outer retina, for example, in the healthy retina after photo-bleaching (Menzler et al., 2014). In addition, the two networks show remarkable differences in their dominant oscillation frequency range as well as in the types and numbers of involved cells (Menzler and Zeck, 2011; Haq et al., 2014). Taken together this suggests that the two networks are self-sustained and can be active independently from each other. However, it is not known if and how they modulate each other. In this mini review, we will discuss: (i) commonalities and differences between these two oscillatory networks as well as possible interaction pathways; (ii) how multiple self

  9. Electronic restoration of vision in those with photoreceptor degenerations.

    PubMed

    O'Brien, Emily E; Greferath, Ursula; Vessey, Kirstan A; Jobling, Andrew I; Fletcher, Erica L

    2012-09-01

    Complete loss of vision is one of the most feared sequelae of retinal disease. Currently, there are few if any treatment options available to patients that may slow or prevent blindness in diseases caused by photoreceptor loss, such as retinitis pigmentosa and age-related macular degeneration. Electronic restoration of vision has emerged over recent years as a safe and viable option for those who have lost substantial numbers of photoreceptors and who are severely vision impaired. Indeed, there has been a dramatic increase in our understanding of what is required to restore vision using an electronic retinal prosthesis. Recent reports show that for some patients, restoration of vision to the point of reading large letters is possible. In this review, we examine the types of implants currently under investigation and the results these devices have achieved clinically. We then consider a range of engineering and biological factors that may need to be considered to improve the visual performance of newer-generation devices. With added research, it is hoped that the level of vision achieved with newer generation devices will steadily improve, resulting in enhanced quality of life for those with severe vision impairment.

  10. Prevalence of age-related macular degeneration among the elderly

    PubMed Central

    Rasoulinejad, Seyed Ahmad; Zarghami, Amin; Hosseini, Seyed Reza; Rajaee, Neda; Rasoulinejad, Seyed Elahe; Mikaniki, Ebrahim

    2015-01-01

    Background: Age-related macular degeneration (AMD) is the leading cause of visual impairment and blindness in elderly population in the developing countries. Previous epidemiological studies revealed various potential modifiable risk factors for this disease. The purpose of this study was to evaluate the prevalence of AMD among elderly living in Babol, North of Iran. Methods: The study population of this cross-sectional study came from the Amirkola Health and Ageing Project (AHAP), the first comprehensive cohort study of the health of people aged 60 years and over in Amirkola, North of Iran. The prevalence of AMD was estimated and its risk was determined using logistic regression analysis (LRA) with regard to variables such as smoking, hyperlipidemia, hypertension and diabetes. Results: Five hundred and five participants with mean age of 71.55±5.9 (ranged 60-89) years entered the study. The prevalence of AMD was 17.6%. There was a significant association between AMD and smoking (P<0.001) but no association was seen with AMD and age, level of education, history of hyperlipidemia, hypertension and diabetes. Multiple LRAs revealed that smoking increased AMD by odds ratio of 5.03 (95% confidence interval 2.47-10.23 p<0.001) as compared to nonsmokers Conclusion: According to our findings, the prevalence of AMD was relatively high and smoking increased the risk of AMD in the elderly population. PMID:26644880

  11. Age-related macular degeneration: experimental and emerging treatments

    PubMed Central

    Hubschman, Jean Pierre; Reddy, Shantan; Schwartz, Steven D

    2009-01-01

    Purpose: This essay reviews the experimental treatments and new imaging modalities that are currently being explored by investigators to help treat patients with age-related macular degeneration (AMD). Design: Interpretative essay. Methods: Literature review and interpretation. Results: Experimental treatments to preserve vision in patients with exudative AMD include blocking vascular endothelial growth factor (VEGF), binding VEGF, and modulating the VEGF receptors. Investigators are also attempting to block signal transduction with receptor tyrosine kinase inhibitors. Experimental treatments for non-exudative AMD include agents that target inflammation, oxidative stress, and implement immune-modulation. The effectiveness of these newer pharmacologic agents has the potential to grow exponentially when used in combination with new and improved imaging modalities that can help identify disease earlier and follow treatment response more precisely. Conclusion: With a better understanding, at the genetic and molecular level, of AMD and the development of superior imaging modalities, investigators are able to offer treatment options that may offer unprecedented visual gains while reducing the need for repetitive treatments. PMID:19668561

  12. Effects of Tobacco Smoking on the Degeneration of the Intervertebral Disc: A Finite Element Study.

    PubMed

    Elmasry, Shady; Asfour, Shihab; de Rivero Vaccari, Juan Pablo; Travascio, Francesco

    2015-01-01

    Tobacco smoking is associated with numerous pathological conditions. Compelling experimental evidence associates smoking to the degeneration of the intervertebral disc (IVD). In particular, it has been shown that nicotine down-regulates both the proliferation rate and glycosaminoglycan (GAG) biosynthesis of disc cells. Moreover, tobacco smoking causes the constriction of the vascular network surrounding the IVD, thus reducing the exchange of nutrients and anabolic agents from the blood vessels to the disc. It has been hypothesized that both nicotine presence in the IVD and the reduced solute exchange are responsible for the degeneration of the disc due to tobacco smoking, but their effects on tissue homeostasis have never been quantified. In this study, a previously presented computational model describing the homeostasis of the IVD was deployed to investigate the effects of impaired solute supply and nicotine-mediated down-regulation of cell proliferation and biosynthetic activity on the health of the disc. We found that the nicotine-mediated down-regulation of cell anabolism mostly affected the GAG concentration at the cartilage endplate, reducing it up to 65% of the value attained in normal physiological conditions. In contrast, the reduction of solutes exchange between blood vessels and disc tissue mostly affected the nucleus pulposus, whose cell density and GAG levels were reduced up to 50% of their normal physiological levels. The effectiveness of quitting smoking on the regeneration of a degenerated IVD was also investigated, and showed to have limited benefit on the health of the disc. A cell-based therapy in conjunction with smoke cessation provided significant improvements in disc health, suggesting that, besides quitting smoking, additional treatments should be implemented in the attempt to recover the health of an IVD degenerated by tobacco smoking.

  13. Effects of Tobacco Smoking on the Degeneration of the Intervertebral Disc: A Finite Element Study

    PubMed Central

    Elmasry, Shady; Asfour, Shihab; de Rivero Vaccari, Juan Pablo; Travascio, Francesco

    2015-01-01

    Tobacco smoking is associated with numerous pathological conditions. Compelling experimental evidence associates smoking to the degeneration of the intervertebral disc (IVD). In particular, it has been shown that nicotine down-regulates both the proliferation rate and glycosaminoglycan (GAG) biosynthesis of disc cells. Moreover, tobacco smoking causes the constriction of the vascular network surrounding the IVD, thus reducing the exchange of nutrients and anabolic agents from the blood vessels to the disc. It has been hypothesized that both nicotine presence in the IVD and the reduced solute exchange are responsible for the degeneration of the disc due to tobacco smoking, but their effects on tissue homeostasis have never been quantified. In this study, a previously presented computational model describing the homeostasis of the IVD was deployed to investigate the effects of impaired solute supply and nicotine-mediated down-regulation of cell proliferation and biosynthetic activity on the health of the disc. We found that the nicotine-mediated down-regulation of cell anabolism mostly affected the GAG concentration at the cartilage endplate, reducing it up to 65% of the value attained in normal physiological conditions. In contrast, the reduction of solutes exchange between blood vessels and disc tissue mostly affected the nucleus pulposus, whose cell density and GAG levels were reduced up to 50% of their normal physiological levels. The effectiveness of quitting smoking on the regeneration of a degenerated IVD was also investigated, and showed to have limited benefit on the health of the disc. A cell-based therapy in conjunction with smoke cessation provided significant improvements in disc health, suggesting that, besides quitting smoking, additional treatments should be implemented in the attempt to recover the health of an IVD degenerated by tobacco smoking. PMID:26301590

  14. Menadione-induced cell degeneration is related to lipid peroxidation in human cancer cells.

    PubMed

    Chiou, T J; Chou, Y T; Tzeng, W F

    1998-01-01

    The role of lipid peroxidation, intracellular glutathione and Ca2+ concentration in menadione-mediated toxicity was investigated in human hepatoma cell lines, Hep G2 and Hep 3B, and in human leukemia cell lines, CCRF-CEM and MOLT-3. Incubation of these cells with 80 microM menadione at 37 degrees C resulted in depletion of intracellular glutathione, increased intracellular Ca2+, and increased lipid peroxidation, events leading to cell degeneration. The sensitivity of these cells to menadione, in order, was: Hep G2 cells > Hep 3B cells > CCRF-CEM cells and MOLT-3 cells. The extent of menadione-induced lipid peroxidation in different cell types followed the same order as did their susceptibility to menadione-induced cell degeneration. The menadione-induced depletion in glutathione level was in the following sequence: Hep G2 cells > MOLT-3 and CCRF-CEM cells > Hep 3B cells. The extent of the menadione-induced increase in the intracellular Ca2+ concentration was: Hep G2 cells > Molt-3 cells > CCRF-CEM cells and Hep 3B cells. Pre-treatment of Hep G2 cells with 20 mM deferoxamine mesylate, an iron chelator, reduced both the menadione-induced cell degeneration and lipid peroxidation; however, it did not prevent the menadione-induced increase in intracellular Ca2+ nor the depletion of glutathione. These data suggest that menadione-induced cell degeneration is directly linked to lipid peroxidation, and that it is less related to the rise in intracellular Ca2+ and the depletion in glutathione content. Dicumarol (an inhibitor of DT diaphorase) enhanced the capacity of menadione to induce Hep 3B cell degeneration from 71.3% to 86.2% after 120 min of menadione treatment at 37 degrees C, but did not have this effect in Hep G2, CCRF-CEM or MOLT-3 cells. The activities of DT diaphorase were 52.4, 39.6, 1.5 and 1.8 nmol cytochrome c reduced/min/mg protein in Hep G2, Hep 3B, CCRF-CEM and MOLT-3 cells, respectively. The activity of DT diaphorase was much higher in Hep G2 cells than

  15. Lipofuscin accumulation, abnormal electrophysiology, and photoreceptor degeneration in mutant ELOVL4 transgenic mice: a model for macular degeneration.

    PubMed

    Karan, G; Lillo, C; Yang, Z; Cameron, D J; Locke, K G; Zhao, Y; Thirumalaichary, S; Li, C; Birch, D G; Vollmer-Snarr, H R; Williams, D S; Zhang, K

    2005-03-15

    Macular degeneration is a heterogeneous group of disorders characterized by photoreceptor degeneration and atrophy of the retinal pigment epithelium (RPE) in the central retina. An autosomal dominant form of Stargardt macular degeneration (STGD) is caused by mutations in ELOVL4, which is predicted to encode an enzyme involved in the elongation of long-chain fatty acids. We generated transgenic mice expressing a mutant form of human ELOVL4 that causes STGD. In these mice, we show that accumulation by the RPE of undigested phagosomes and lipofuscin, including the fluorophore, 2-[2,6-dimethyl-8-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1E,3E,5E,7E-octatetraenyl]-1-(2-hyydroxyethyl)-4-[4-methyl-6-(2,6,6,-trimethyl-1-cyclohexen-1-yl)-1E,3E,5E-hexatrienyl]-pyridinium (A2E) is followed by RPE atrophy. Subsequently, photoreceptor degeneration occurs in the central retina in a pattern closely resembling that of human STGD and age-related macular degeneration. The ELOVL4 transgenic mice thus provide a good model for both STGD and dry age-related macular degeneration, and represent a valuable tool for studies on therapeutic intervention in these forms of blindness. PMID:15749821

  16. Strongly magnetized cold electron degenerate gas: Mass-radius relation of the collapsed star

    NASA Astrophysics Data System (ADS)

    Das, Upasana; Mukhopadhyay, Banibrata

    2012-07-01

    We consider a relativistic, degenerate electron gas at zero-temperature under the influence of a strong, uniform, static magnetic field, neglecting any form of interactions. Since the density of states for the electrons changes due to the presence of the magnetic field (which gives rise to Landau quantization), the corresponding equation of state also gets modified. In order to investigate the effect of very strong magnetic field, we focus only on systems in which a maximum of either one, two or three Landau level(s) is/are occupied. This is important since, if a very large number of Landau levels are filled, it implies a very low magnetic field strength which yields back Chandrasekhar's celebrated non-magnetic results. The maximum number of Landau levels occupied is fixed by the correct choice of two parameters, namely the magnetic field strength and the maximum Fermi energy of the system. We study the equations of state of these one-level, two-level and three-level systems and compare them by taking three different maximum Fermi energies. We also find the effect of the strong magnetic field on the mass-radius relation of the underlying star composed of the gas stated above. We obtain an interesting theoretical result that, it is possible to have an electron degenerate static star with a mass significantly greater than the Chandrasekhar limit, provided it has an appropriate magnetic field strength and central density.

  17. Statins for age-related macular degeneration

    PubMed Central

    Gehlbach, Peter; Li, Tianjing; Hatef, Elham

    2016-01-01

    Background Age-related macular degeneration (AMD) is a progressive late onset disorder of the macula affecting central vision. Age-related macular degeneration is the leading cause of blindness in people over 65 years in industrialized countries. Recent epidemiologic, genetic, and pathological evidence has shown AMD shares a number of risk factors with atherosclerosis, leading to the hypothesis that statins may exert protective effects in AMD. Objectives The objective of this review was to examine the effectiveness of statins compared with other treatments, no treatment, or placebo in delaying the onset and progression of AMD. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 6), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2014), EMBASE (January 1980 to June 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to June 2014), PubMed (January 1946 to June 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov), and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 5 June 2014. Selection criteria We included randomized controlled trials (RCTs) that compared statins with other treatments, no treatment, or placebo in participants who were either susceptible to or diagnosed as having early stages of AMD. Data collection and analysis We used standard methodological procedures expected by The Cochrane Collaboration. Two authors independently evaluated the search results against the selection criteria, abstracted data, and assessed risk of bias. We did not perform meta-analysis due to heterogeneity in the interventions and outcomes among the

  18. Statins for age-related macular degeneration

    PubMed Central

    Gehlbach, Peter; Li, Tianjing; Hatef, Elham

    2016-01-01

    Background Age-related macular degeneration (AMD) is a progressive late onset disorder of the macula affecting central vision. Age-related macular degeneration is the leading cause of blindness in people over 65 years in industrialized countries. Recent epidemiologic, genetic, and pathological evidence has shown AMD shares a number of risk factors with atherosclerosis, leading to the hypothesis that statins may exert protective effects in AMD. Objectives The objective of this review was to examine the effectiveness of statins compared with other treatments, no treatment, or placebo in delaying the onset and progression of AMD. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 6), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2014), EMBASE (January 1980 to June 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to June 2014), PubMed (January 1946 to June 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov), and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 5 June 2014. Selection criteria We included randomized controlled trials (RCTs) that compared statins with other treatments, no treatment, or placebo in participants who were either susceptible to or diagnosed as having early stages of AMD. Data collection and analysis We used standard methodological procedures expected by The Cochrane Collaboration. Two authors independently evaluated the search results against the selection criteria, abstracted data, and assessed risk of bias. We did not perform meta-analysis due to heterogeneity in the interventions and outcomes among the

  19. Theoretical and uniaxial experimental evaluation of human annulus fibrosus degeneration.

    PubMed

    O'Connell, Grace D; Guerin, Heather L; Elliott, Dawn M

    2009-11-01

    The highly organized structure and composition of the annulus fibrosus provides the tissue with mechanical behaviors that include anisotropy and nonlinearity. Mathematical models are necessary to interpret and elucidate the meaning of directly measured mechanical properties and to understand the structure-function relationships of the tissue components, namely, the fibers and extrafibrillar matrix. This study models the annulus fibrosus as a combination of strain energy functions describing the fibers, matrix, and their interactions. The objective was to quantify the behavior of both nondegenerate and degenerate annulus fibrosus tissue using uniaxial tensile experimental data. Mechanical testing was performed with samples oriented along the circumferential, axial, and radial directions. For samples oriented along the radial direction, the toe-region modulus was 2x stiffer with degeneration. However, no other differences in measured mechanical properties were observed with degeneration. The constitutive model fit well to samples oriented along the radial and circumferential directions (R(2)> or =0.97). The fibers supported the highest proportion of stress for circumferential loading at 60%. There was a 70% decrease in the matrix contribution to stress from the toe-region to the linear-region of both the nondegenerate and degenerate tissue. The shear fiber-matrix interaction (FMI) contribution increased by 80% with degeneration in the linear-region. Samples oriented along the radial and axial direction behaved similarly under uniaxial tension (modulus=0.32 MPa versus 0.37 MPa), suggesting that uniaxial testing in the axial direction is not appropriate for quantifying the mechanics of a fiber reinforcement in the annulus. In conclusion, the structurally motivated nonlinear anisotropic hyperelastic constitutive model helps to further understand the effect of microstructural changes with degeneration, suggesting that remodeling in the subcomponents (i.e., the collagen

  20. Trilayer graphene nanoribbon carrier statistics in degenerate and non degenerate limits

    NASA Astrophysics Data System (ADS)

    Rahmani, M.; Ahmadi, M. T.; Webb, J. F.; Shayesteh, N.; Mousavi, S. M.; Sadeghi, H.; Ismail, R.

    2012-11-01

    We present trilayer graphene nanoribbon carrier statistics in the degenerate and the nondegenerate limits. Within zero to 3kBT from the conduction or valence band edgers high concentrations of carriers sensitively depend on a normalized Fermi energy which is independent of temperature. The effect of different stacking orders of graphene multilayers on the electric field induced band gap is studied. The gap for trilayer graphene with the ABC stacking is much larger than the corresponding gap for the ABA trilayer. The gap for the different types of stacking is much larger as compared to the case of Bernal stacking. A non-monotonic dependence of the true energy gap in trilayer graphene on the charge density is investigated along with the electronic low-energy band structure of ABC stacked multilayer graphene. The band structure of trilayer graphene systems in the presence of a perpendicular electric field is obtained using a tight-binding approach.

  1. Diagnostic Performance and Reliability of Ultrasonography for Fatty Degeneration of the Rotator Cuff Muscles

    PubMed Central

    Wall, Lindley B.; Teefey, Sharlene A.; Middleton, William D.; Dahiya, Nirvikar; Steger-May, Karen; Kim, H. Mike; Wessell, Daniel; Yamaguchi, Ken

    2012-01-01

    ) and moderate for the teres minor (kappa = 0.47). The interobserver reliability for MRI was substantial for the supraspinatus and infraspinatus (kappa = 0.76 and 0.77, respectively) and moderate for the teres minor (kappa = 0.59). For ultrasonography, the interobserver reliability was substantial for all three muscles (kappa = 0.71 for the supraspinatus, 0.65 for the infraspinatus, and 0.72 for the teres minor). Conclusions: The diagnostic performance of ultrasonography in identifying and grading fatty degeneration of the rotator cuff muscles was comparable with that of MRI. Ultrasonography can be used as the primary diagnostic imaging modality for fatty changes in rotator cuff muscles. Level of Evidence: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence. PMID:22717835

  2. Near-degenerate stereomorphs of the doubly-chiral hcp-{213̅1} surface

    NASA Astrophysics Data System (ADS)

    Jenkins, S. J.

    2010-09-01

    The surfaces of hcp crystals can show a variety of structural features and classes of symmetry that differ markedly from those of simpler fcc or bcc crystals. The hcp-{213̅1} surface, for example, can occur in four distinct stereomorphs, interconverted by a combination of mirror operations (linking degenerate enantiomorphically related surfaces) and/or the removal of the outermost atomic layer (linking non-degenerate diamorphically related surfaces). The strict pattern of degeneracy amongst these stereomorphs is analogous to that found for molecules with two chiral centres, and hence it is possible to view this system as doubly-chiral. Simple nearest-neighbour bond-counting arguments, however, suggest that for {213̅1} even the diamorphically related cases should be near-degenerate, despite the fact that they differ in having either a notably short or notably long interlayer spacing between the outermost layers (ideal spacing ratio 1:5). In the present work, this counterintuitive result is confirmed at the level of density functional theory, both for the ideal and relaxed {213̅1} surfaces of Co, Ru and Re.

  3. Molecular response of chorioretinal endothelial cells to complement injury: implications for macular degeneration.

    PubMed

    Zeng, Shemin; Whitmore, S Scott; Sohn, Elliott H; Riker, Megan J; Wiley, Luke A; Scheetz, Todd E; Stone, Edwin M; Tucker, Budd A; Mullins, Robert F

    2016-02-01

    Age-related macular degeneration (AMD) is a common, blinding disease of the elderly in which macular photoreceptor cells, retinal pigment epithelium and choriocapillaris endothelial cells ultimately degenerate. Recent studies have found that degeneration of the choriocapillaris occurs early in this disease and that endothelial cell drop-out is concomitant with increased deposition of the complement membrane attack complex (MAC) at the choroidal endothelium. However, the impact of MAC injury to choroidal endothelial cells is poorly understood. To model this event in vitro, and to study the downstream consequences of MAC injury, endothelial cells were exposed to complement from human serum, compared to heat-inactivated serum, which lacks complement components. Cells exposed to complement components in human serum showed increased labelling with antibodies directed against the MAC, time- and dose-dependent cell death, as assessed by lactate dehydrogenase assay and increased permeability. RNA-Seq analysis following complement injury revealed increased expression of genes associated with angiogenesis including matrix metalloproteinase (MMP)-3 and -9, and VEGF-A. The MAC-induced increase in MMP9 RNA expression was validated using C5-depleted serum compared to C5-reconstituted serum. Increased levels of MMP9 were also established, using western blot and zymography. These data suggest that, in addition to cell lysis, complement attack on choroidal endothelial cells promotes an angiogenic phenotype in surviving cells.

  4. TMJ degeneration in SAMP8 mice is accompanied by deranged Ihh signaling.

    PubMed

    Ishizuka, Y; Shibukawa, Y; Nagayama, M; Decker, R; Kinumatsu, T; Saito, A; Pacifici, M; Koyama, E

    2014-03-01

    The temporomandibular joint (TMJ) functions as a load-bearing diarthrodial joint during mastication, and its continuous use and stress can lead to degeneration over age. Using senescence-accelerated (SAMP8) mice that develop early osteoarthritis-like changes in synovial joints at high frequency, we analyzed possible molecular mechanisms of TMJ degeneration and tested whether and how malocclusion may accelerate it. Condylar articular cartilage in young SAMP8 mice displayed early-onset osteoarthritic changes that included reductions in superficial/chondroprogenitor cell number, proteoglycan/collagen content, and Indian hedgehog (Ihh)-expressing chondrocytes. Following malocclusion induced by tooth milling, the SAMP8 condyles became morphologically defective, displayed even lower proteoglycan levels, and underwent abnormal chondrocyte maturation compared with malocclusion-treated condyles in wild-type mice. Malocclusion also induced faster progression of pathologic changes with increasing age in SAMP8 condyles as indicated by decreased PCNA-positive proliferating chondroprogenitors and increased TUNEL-positive apoptotic cells. These changes were accompanied by steeper reductions in Ihh signaling and by expression of matrix metalloproteinase 13 at the chondro-osseous junction in SAMP8 articular cartilage. In sum, we show for the first time that precocious TMJ degeneration in SAMP8 mice is accompanied by--and possibly attributable to--altered Ihh signaling and that occlusal dysfunction accelerates progression toward degenerative TMJ disease in this model. PMID:24453178

  5. TMJ Degeneration in SAMP8 Mice is Accompanied by Deranged Ihh Signaling

    PubMed Central

    Ishizuka, Y.; Shibukawa, Y.; Nagayama, M.; Decker, R.; Kinumatsu, T.; Saito, A.; Pacifici, M.; Koyama, E.

    2014-01-01

    The temporomandibular joint (TMJ) functions as a load-bearing diarthrodial joint during mastication, and its continuous use and stress can lead to degeneration over age. Using senescence-accelerated (SAMP8) mice that develop early osteoarthritis-like changes in synovial joints at high frequency, we analyzed possible molecular mechanisms of TMJ degeneration and tested whether and how malocclusion may accelerate it. Condylar articular cartilage in young SAMP8 mice displayed early-onset osteoarthritic changes that included reductions in superficial/chondroprogenitor cell number, proteoglycan/collagen content, and Indian hedgehog (Ihh)-expressing chondrocytes. Following malocclusion induced by tooth milling, the SAMP8 condyles became morphologically defective, displayed even lower proteoglycan levels, and underwent abnormal chondrocyte maturation compared with malocclusion-treated condyles in wild-type mice. Malocclusion also induced faster progression of pathologic changes with increasing age in SAMP8 condyles as indicated by decreased PCNA-positive proliferating chondroprogenitors and increased TUNEL-positive apoptotic cells. These changes were accompanied by steeper reductions in Ihh signaling and by expression of matrix metalloproteinase 13 at the chondro-osseous junction in SAMP8 articular cartilage. In sum, we show for the first time that precocious TMJ degeneration in SAMP8 mice is accompanied by—and possibly attributable to—altered Ihh signaling and that occlusal dysfunction accelerates progression toward degenerative TMJ disease in this model. PMID:24453178

  6. Role of Cytokines in Intervertebral Disc Degeneration: Pain and Disc-content

    PubMed Central

    Risbud, Makarand V.; Shapiro, Irving. M

    2014-01-01

    Degeneration of the intervertebral disc is the major contributor to back/neck and radicular pain. It is characterized by an elevation in levels of the inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1 α/β, IL-6 and IL-17 secreted by the disc cells themselves; these cytokines promote matrix degradation, chemokine production and changes in cell phenotype. The resulting imbalance between catabolic and anabolic responses leads to degeneration, as well as herniation and radicular pain. Release of chemokines from degenerating discs promote infiltration and activation of T and B cells, macrophages, neutrophils, and mast cells further amplifying the inflammatory cascade. Immunocyte migration into the disc is accompanied by the appearance of microvasculature and nerve fibers arising from the dorsal root ganglion (DRG). In this inflammatory milieu, neurogenic factors in particular nerve growth factor (NGF) and brain-derive neurotrophic factor (BDNF) generated by disc and immune cells induce expression of pain associated cation channels in DRGs. Depolarization of these channels is likely to promote discogenic and radicular pain and reinforce the cytokine-mediated degenerative cascade. Taken together, the enhanced understanding of the contribution of cytokines and immune cells to catabolic and nociceptive processes provide new targets for treating symptomatic disc disease. PMID:24166242

  7. Deletion of autophagy inducer RB1CC1 results in degeneration of the retinal pigment epithelium.

    PubMed

    Yao, Jingyu; Jia, Lin; Khan, Naheed; Lin, Chengmao; Mitter, Sayak K; Boulton, Michael E; Dunaief, Joshua L; Klionsky, Daniel J; Guan, Jun-Lin; Thompson, Debra A; Zacks, David N

    2015-01-01

    Autophagy regulates cellular homeostasis and response to environmental stress. Within the retinal pigment epithelium (RPE) of the eye, the level of autophagy can change with both age and disease. The purpose of this study is to determine the relationship between reduced autophagy and age-related degeneration of the RPE. The gene encoding RB1CC1/FIP200 (RB1-inducible coiled-coil 1), a protein essential for induction of autophagy, was selectively knocked out in the RPE by crossing Best1-Cre mice with mice in which the Rb1cc1 gene was flanked with Lox-P sites (Rb1cc1(flox/flox)). Ex vivo and in vivo analyses, including western blot, immunohistochemistry, transmission electron microscopy, fundus photography, optical coherence tomography, fluorescein angiography, and electroretinography were performed to assess the structure and function of the retina as a function of age. Deletion of Rb1cc1 resulted in multiple autophagy defects within the RPE including decreased conversion of LC3-I to LC3-II, accumulation of autophagy-targeted precursors, and increased numbers of mitochondria. Age-dependent degeneration of the RPE occurred, with formation of atrophic patches, subretinal migration of activated microglial cells, subRPE deposition of inflammatory and oxidatively damaged proteins, subretinal drusenoid deposits, and occasional foci of choroidal neovascularization. There was secondary loss of photoreceptors overlying the degenerated RPE and reduction in the electroretinogram. These observations are consistent with a critical role of autophagy in the maintenance of normal homeostasis in the aging RPE, and indicate that disruption of autophagy leads to retinal phenotypes associated with age-related degeneration.

  8. Deletion of autophagy inducer RB1CC1 results in degeneration of the retinal pigment epithelium.

    PubMed

    Yao, Jingyu; Jia, Lin; Khan, Naheed; Lin, Chengmao; Mitter, Sayak K; Boulton, Michael E; Dunaief, Joshua L; Klionsky, Daniel J; Guan, Jun-Lin; Thompson, Debra A; Zacks, David N

    2015-01-01

    Autophagy regulates cellular homeostasis and response to environmental stress. Within the retinal pigment epithelium (RPE) of the eye, the level of autophagy can change with both age and disease. The purpose of this study is to determine the relationship between reduced autophagy and age-related degeneration of the RPE. The gene encoding RB1CC1/FIP200 (RB1-inducible coiled-coil 1), a protein essential for induction of autophagy, was selectively knocked out in the RPE by crossing Best1-Cre mice with mice in which the Rb1cc1 gene was flanked with Lox-P sites (Rb1cc1(flox/flox)). Ex vivo and in vivo analyses, including western blot, immunohistochemistry, transmission electron microscopy, fundus photography, optical coherence tomography, fluorescein angiography, and electroretinography were performed to assess the structure and function of the retina as a function of age. Deletion of Rb1cc1 resulted in multiple autophagy defects within the RPE including decreased conversion of LC3-I to LC3-II, accumulation of autophagy-targeted precursors, and increased numbers of mitochondria. Age-dependent degeneration of the RPE occurred, with formation of atrophic patches, subretinal migration of activated microglial cells, subRPE deposition of inflammatory and oxidatively damaged proteins, subretinal drusenoid deposits, and occasional foci of choroidal neovascularization. There was secondary loss of photoreceptors overlying the degenerated RPE and reduction in the electroretinogram. These observations are consistent with a critical role of autophagy in the maintenance of normal homeostasis in the aging RPE, and indicate that disruption of autophagy leads to retinal phenotypes associated with age-related degeneration. PMID:26075877

  9. Laplacian versus adjacency matrix in quantum walk search

    NASA Astrophysics Data System (ADS)

    Wong, Thomas G.; Tarrataca, Luís; Nahimov, Nikolay

    2016-10-01

    A quantum particle evolving by Schrödinger's equation contains, from the kinetic energy of the particle, a term in its Hamiltonian proportional to Laplace's operator. In discrete space, this is replaced by the discrete or graph Laplacian, which gives rise to a continuous-time quantum walk. Besides this natural definition, some quantum walk algorithms instead use the adjacency matrix to effect the walk. While this is equivalent to the Laplacian for regular graphs, it is different for non-regular graphs and is thus an inequivalent quantum walk. We algorithmically explore this distinction by analyzing search on the complete bipartite graph with multiple marked vertices, using both the Laplacian and adjacency matrix. The two walks differ qualitatively and quantitatively in their required jumping rate, runtime, sampling of marked vertices, and in what constitutes a natural initial state. Thus the choice of the Laplacian or adjacency matrix to effect the walk has important algorithmic consequences.

  10. Laplacian versus adjacency matrix in quantum walk search

    NASA Astrophysics Data System (ADS)

    Wong, Thomas G.; Tarrataca, Luís; Nahimov, Nikolay

    2016-06-01

    A quantum particle evolving by Schrödinger's equation contains, from the kinetic energy of the particle, a term in its Hamiltonian proportional to Laplace's operator. In discrete space, this is replaced by the discrete or graph Laplacian, which gives rise to a continuous-time quantum walk. Besides this natural definition, some quantum walk algorithms instead use the adjacency matrix to effect the walk. While this is equivalent to the Laplacian for regular graphs, it is different for non-regular graphs and is thus an inequivalent quantum walk. We algorithmically explore this distinction by analyzing search on the complete bipartite graph with multiple marked vertices, using both the Laplacian and adjacency matrix. The two walks differ qualitatively and quantitatively in their required jumping rate, runtime, sampling of marked vertices, and in what constitutes a natural initial state. Thus the choice of the Laplacian or adjacency matrix to effect the walk has important algorithmic consequences.

  11. Aberrant gene expression in mucosa adjacent to tumor reveals a molecular crosstalk in colon cancer

    PubMed Central

    2014-01-01

    Background A colorectal tumor is not an isolated entity growing in a restricted location of the body. The patient’s gut environment constitutes the framework where the tumor evolves and this relationship promotes and includes a complex and tight correlation of the tumor with inflammation, blood vessels formation, nutrition, and gut microbiome composition. The tumor influence in the environment could both promote an anti-tumor or a pro-tumor response. Methods A set of 98 paired adjacent mucosa and tumor tissues from colorectal cancer (CRC) patients and 50 colon mucosa from healthy donors (246 samples in total) were included in this work. RNA extracted from each sample was hybridized in Affymetrix chips Human Genome U219. Functional relationships between genes were inferred by means of systems biology using both transcriptional regulation networks (ARACNe algorithm) and protein-protein interaction networks (BIANA software). Results Here we report a transcriptomic analysis revealing a number of genes activated in adjacent mucosa from CRC patients, not activated in mucosa from healthy donors. A functional analysis of these genes suggested that this active reaction of the adjacent mucosa was related to the presence of the tumor. Transcriptional and protein-interaction networks were used to further elucidate this response of normal gut in front of the tumor, revealing a crosstalk between proteins secreted by the tumor and receptors activated in the adjacent colon tissue; and vice versa. Remarkably, Slit family of proteins activated ROBO receptors in tumor whereas tumor-secreted proteins transduced a cellular signal finally activating AP-1 in adjacent tissue. Conclusions The systems-level approach provides new insights into the micro-ecology of colorectal tumorogenesis. Disrupting this intricate molecular network of cell-cell communication and pro-inflammatory microenvironment could be a therapeutic target in CRC patients. PMID:24597571

  12. Notochord Cells in Intervertebral Disc Development and Degeneration

    PubMed Central

    McCann, Matthew R.; Séguin, Cheryle A.

    2016-01-01

    The intervertebral disc is a complex structure responsible for flexibility, multi-axial motion, and load transmission throughout the spine. Importantly, degeneration of the intervertebral disc is thought to be an initiating factor for back pain. Due to a lack of understanding of the pathways that govern disc degeneration, there are currently no disease-modifying treatments to delay or prevent degenerative disc disease. This review presents an overview of our current understanding of the developmental processes that regulate intervertebral disc formation, with particular emphasis on the role of the notochord and notochord-derived cells in disc homeostasis and how their loss can result in degeneration. We then describe the role of small animal models in understanding the development of the disc and their use to interrogate disc degeneration and associated pathologies. Finally, we highlight essential development pathways that are associated with disc degeneration and/or implicated in the reparative response of the tissue that might serve as targets for future therapeutic approaches. PMID:27252900

  13. RADIOLOGICAL ANALYSIS OF EXPERIMENTAL DISC DEGENERATION IN RABBITS

    PubMed Central

    Vialle, Emiliano; Vialle, Luiz Roberto; Arruda, André de Oliveira; Riet, Ricardo Nascimento; Krieger, Antônio Bernardo de Queiroz

    2015-01-01

    Objective: To validate radiographic evaluation of a rabbit model for disc degeneration. Methods: Lumbar intervertebral discs of New Zealand rabbits were stabbed three times with a 18G needle at a limited depth of 5mm, through lateral approach. Serial radiographic images were taken on the early pre-and postoperative periods, and after four, eight and 12 weeks of the procedure, with subsequent analysis of disc height, osteophyte formation, endplate sclerosis, and presence of disc degeneration. The statistical analysis of data was validated by the Kappa coefficient, with a confidence interval (CI) of 95%. Results: A significant reduction of disc space was found on AP X-ray images after 12 postoperative weeks, with Kappa = 0.489 for CI 95% (0.25-0.72) with p < 0.001. X-ray signs of disc degeneration also presented Kappa = 0.63 for CI 95% (0.39-0.86) with p < 0.001. The remaining assessed criteria showed positive results, but with a lower Kappa value. Conclusion: The disc degeneration model using rabbits as proposed in this study was shown to be feasible, with positive X-ray correlation between pre- and postoperative images, validating the potential to induce disc degeneration in this animal model for future studies. PMID:27022512

  14. Rapid Y degeneration and dosage compensation in plant sex chromosomes

    PubMed Central

    Papadopulos, Alexander S. T.; Chester, Michael; Ridout, Kate; Filatov, Dmitry A.

    2015-01-01

    The nonrecombining regions of animal Y chromosomes are known to undergo genetic degeneration, but previous work has failed to reveal large-scale gene degeneration on plant Y chromosomes. Here, we uncover rapid and extensive degeneration of Y-linked genes in a plant species, Silene latifolia, that evolved sex chromosomes de novo in the last 10 million years. Previous transcriptome-based studies of this species missed unexpressed, degenerate Y-linked genes. To identify sex-linked genes, regardless of their expression, we sequenced male and female genomes of S. latifolia and integrated the genomic contigs with a high-density genetic map. This revealed that 45% of Y-linked genes are not expressed, and 23% are interrupted by premature stop codons. This contrasts with X-linked genes, in which only 1.3% of genes contained stop codons and 4.3% of genes were not expressed in males. Loss of functional Y-linked genes is partly compensated for by gene-specific up-regulation of X-linked genes. Our results demonstrate that the rate of genetic degeneration of Y-linked genes in S. latifolia is as fast as in animals, and that the evolutionary trajectories of sex chromosomes are similar in the two kingdoms. PMID:26438872

  15. Rapid Y degeneration and dosage compensation in plant sex chromosomes.

    PubMed

    Papadopulos, Alexander S T; Chester, Michael; Ridout, Kate; Filatov, Dmitry A

    2015-10-20

    The nonrecombining regions of animal Y chromosomes are known to undergo genetic degeneration, but previous work has failed to reveal large-scale gene degeneration on plant Y chromosomes. Here, we uncover rapid and extensive degeneration of Y-linked genes in a plant species, Silene latifolia, that evolved sex chromosomes de novo in the last 10 million years. Previous transcriptome-based studies of this species missed unexpressed, degenerate Y-linked genes. To identify sex-linked genes, regardless of their expression, we sequenced male and female genomes of S. latifolia and integrated the genomic contigs with a high-density genetic map. This revealed that 45% of Y-linked genes are not expressed, and 23% are interrupted by premature stop codons. This contrasts with X-linked genes, in which only 1.3% of genes contained stop codons and 4.3% of genes were not expressed in males. Loss of functional Y-linked genes is partly compensated for by gene-specific up-regulation of X-linked genes. Our results demonstrate that the rate of genetic degeneration of Y-linked genes in S. latifolia is as fast as in animals, and that the evolutionary trajectories of sex chromosomes are similar in the two kingdoms.

  16. Mechanisms of Distal Axonal Degeneration in Peripheral Neuropathies

    PubMed Central

    Cashman, Christopher R.; Höke, Ahmet

    2015-01-01

    Peripheral neuropathy is a common complication of a variety of diseases and treatments, including diabetes, cancer chemotherapy, and infectious causes (HIV, hepatitis C, and Campylobacter jejuni). Despite the fundamental difference between these insults, peripheral neuropathy develops as a combination of just six primary mechanisms: altered metabolism, covalent modification, altered organelle function and reactive oxygen species formation, altered intracellular and inflammatory signaling, slowed axonal transport, and altered ion channel dynamics and expression. All of these pathways converge to lead to axon dysfunction and symptoms of neuropathy. The detailed mechanisms of axon degeneration itself have begun to be elucidated with studies of animal models with altered degeneration kinetics, including the slowed Wallerian degeneration (Wlds) and Sarmknockout animal models. These studies have shown axonal degeneration to occur througha programmed pathway of injury signaling and cytoskeletal degradation. Insights into the common disease insults that converge on the axonal degeneration pathway promise to facilitate the development of therapeutics that may be effective against other mechanisms of neurodegeneration. PMID:25617478

  17. Mechanisms of distal axonal degeneration in peripheral neuropathies.

    PubMed

    Cashman, Christopher R; Höke, Ahmet

    2015-06-01

    Peripheral neuropathy is a common complication of a variety of diseases and treatments, including diabetes, cancer chemotherapy, and infectious causes (HIV, hepatitis C, and Campylobacter jejuni). Despite the fundamental difference between these insults, peripheral neuropathy develops as a combination of just six primary mechanisms: altered metabolism, covalent modification, altered organelle function and reactive oxygen species formation, altered intracellular and inflammatory signaling, slowed axonal transport, and altered ion channel dynamics and expression. All of these pathways converge to lead to axon dysfunction and symptoms of neuropathy. The detailed mechanisms of axon degeneration itself have begun to be elucidated with studies of animal models with altered degeneration kinetics, including the slowed Wallerian degeneration (Wld(S)) and Sarm knockout animal models. These studies have shown axonal degeneration to occur through a programmed pathway of injury signaling and cytoskeletal degradation. Insights into the common disease insults that converge on the axonal degeneration pathway promise to facilitate the development of therapeutics that may be effective against other mechanisms of neurodegeneration.

  18. Mechanisms of distal axonal degeneration in peripheral neuropathies.

    PubMed

    Cashman, Christopher R; Höke, Ahmet

    2015-06-01

    Peripheral neuropathy is a common complication of a variety of diseases and treatments, including diabetes, cancer chemotherapy, and infectious causes (HIV, hepatitis C, and Campylobacter jejuni). Despite the fundamental difference between these insults, peripheral neuropathy develops as a combination of just six primary mechanisms: altered metabolism, covalent modification, altered organelle function and reactive oxygen species formation, altered intracellular and inflammatory signaling, slowed axonal transport, and altered ion channel dynamics and expression. All of these pathways converge to lead to axon dysfunction and symptoms of neuropathy. The detailed mechanisms of axon degeneration itself have begun to be elucidated with studies of animal models with altered degeneration kinetics, including the slowed Wallerian degeneration (Wld(S)) and Sarm knockout animal models. These studies have shown axonal degeneration to occur through a programmed pathway of injury signaling and cytoskeletal degradation. Insights into the common disease insults that converge on the axonal degeneration pathway promise to facilitate the development of therapeutics that may be effective against other mechanisms of neurodegeneration. PMID:25617478

  19. Inflammation and white matter degeneration persist for years after a single traumatic brain injury.

    PubMed

    Johnson, Victoria E; Stewart, Janice E; Begbie, Finn D; Trojanowski, John Q; Smith, Douglas H; Stewart, William

    2013-01-01

    A single traumatic brain injury is associated with an increased risk of dementia and, in a proportion of patients surviving a year or more from injury, the development of hallmark Alzheimer's disease-like pathologies. However, the pathological processes linking traumatic brain injury and neurodegenerative disease remain poorly understood. Growing evidence supports a role for neuroinflammation in the development of Alzheimer's disease. In contrast, little is known about the neuroinflammatory response to brain injury and, in particular, its temporal dynamics and any potential role in neurodegeneration. Cases of traumatic brain injury with survivals ranging from 10 h to 47 years post injury (n = 52) and age-matched, uninjured control subjects (n = 44) were selected from the Glasgow Traumatic Brain Injury archive. From these, sections of the corpus callosum and adjacent parasaggital cortex were examined for microglial density and morphology, and for indices of white matter pathology and integrity. With survival of ≥3 months from injury, cases with traumatic brain injury frequently displayed extensive, densely packed, reactive microglia (CR3/43- and/or CD68-immunoreactive), a pathology not seen in control subjects or acutely injured cases. Of particular note, these reactive microglia were present in 28% of cases with survival of >1 year and up to 18 years post-trauma. In cases displaying this inflammatory pathology, evidence of ongoing white matter degradation could also be observed. Moreover, there was a 25% reduction in the corpus callosum thickness with survival >1 year post-injury. These data present striking evidence of persistent inflammation and ongoing white matter degeneration for many years after just a single traumatic brain injury in humans. Future studies to determine whether inflammation occurs in response to or, conversely, promotes white matter degeneration will be important. These findings may provide parallels for studying neurodegenerative disease

  20. On the Adjacent Eccentric Distance Sum Index of Graphs

    PubMed Central

    Qu, Hui; Cao, Shujuan

    2015-01-01

    For a given graph G, ε(v) and deg(v) denote the eccentricity and the degree of the vertex v in G, respectively. The adjacent eccentric distance sum index of a graph G is defined as ξsv(G)=∑v∈V(G)ε(v)D(v)deg(v), where D(v)=∑u∈V(G)d(u,v) is the sum of all distances from the vertex v. In this paper we derive some bounds for the adjacent eccentric distance sum index in terms of some graph parameters, such as independence number, covering number, vertex connectivity, chromatic number, diameter and some other graph topological indices. PMID:26091095

  1. Nonlinear spin wave coupling in adjacent magnonic crystals

    NASA Astrophysics Data System (ADS)

    Sadovnikov, A. V.; Beginin, E. N.; Morozova, M. A.; Sharaevskii, Yu. P.; Grishin, S. V.; Sheshukova, S. E.; Nikitov, S. A.

    2016-07-01

    We have experimentally studied the coupling of spin waves in the adjacent magnonic crystals. Space- and time-resolved Brillouin light-scattering spectroscopy is used to demonstrate the frequency and intensity dependent spin-wave energy exchange between the side-coupled magnonic crystals. The experiments and the numerical simulation of spin wave propagation in the coupled periodic structures show that the nonlinear phase shift of spin wave in the adjacent magnonic crystals leads to the nonlinear switching regime at the frequencies near the forbidden magnonic gap. The proposed side-coupled magnonic crystals represent a significant advance towards the all-magnonic signal processing in the integrated magnonic circuits.

  2. Electrophysiology Alterations in Primary Visual Cortex Neurons of Retinal Degeneration (S334ter-line-3) Rats

    PubMed Central

    Chen, Ke; Wang, Yi; Liang, Xiaohua; Zhang, Yihuai; Ng, Tsz Kin; Chan, Leanne Lai Hang

    2016-01-01

    The dynamic nature of the brain is critical for the success of treatments aimed at restoring vision at the retinal level. The success of these treatments relies highly on the functionality of the surviving neurons along the entire visual pathway. Electrophysiological properties at the retina level have been investigated during the progression of retinal degeneration; however, little is known about the changes in electrophysiological properties that occur in the primary visual cortex (V1) during the course of retinal degeneration. By conducting extracellular recording, we examined the electrophysiological properties of V1 in S334ter-line-3 rats (a transgenic model of retinal degeneration developed to express a rhodopsin mutation similar to that found in human retinitis pigmentosa patients). We measured the orientation tuning, spatial and temporal frequency tunings and the receptive field (RF) size for 127 V1 neurons from 11 S334ter-3 rats and 10 Long-Evans (LE) rats. V1 neurons in the S334ter-3 rats showed weaker orientation selectivity, lower optimal spatial and temporal frequency values and a smaller receptive field size compared to the LE rats. These results suggest that the visual cognitive ability significantly changes during retinal degeneration. PMID:27225415

  3. Molecular mechanisms of cell death in intervertebral disc degeneration (Review)

    PubMed Central

    ZHANG, FAN; ZHAO, XUELING; SHEN, HONGXING; ZHANG, CAIGUO

    2016-01-01

    Intervertebral discs (IVDs) are complex structures that consist of three parts, namely, nucleus pulposus, annulus fibrosus and cartilage endplates. With aging, IVDs gradually degenerate as a consequence of many factors, such as microenvironment changes and cell death. Human clinical trial and animal model studies have documented that cell death, particularly apoptosis and autophagy, significantly contribute to IVD degeneration. The mechanisms underlying this phenomenon include the activation of apoptotic pathways and the regulation of autophagy in response to nutrient deprivation and multiple stresses. In this review, we briefly summarize recent progress in understanding the function and regulation of apoptosis and autophagy signaling pathways. In particular, we focus on studies that reveal the functional mechanisms of these pathways in IVD degeneration. PMID:27121482

  4. Accumulation of Rhodopsin in Late Endosomes Triggers Photoreceptor Cell Degeneration

    PubMed Central

    Chinchore, Yashodhan; Mitra, Amitavo; Dolph, Patrick J.

    2009-01-01

    Progressive retinal degeneration is the underlying feature of many human retinal dystrophies. Previous work using Drosophila as a model system and analysis of specific mutations in human rhodopsin have uncovered a connection between rhodopsin endocytosis and retinal degeneration. In these mutants, rhodopsin and its regulatory protein arrestin form stable complexes, and endocytosis of these complexes causes photoreceptor cell death. In this study we show that the internalized rhodopsin is not degraded in the lysosome but instead accumulates in the late endosomes. Using mutants that are defective in late endosome to lysosome trafficking, we were able to show that rhodopsin accumulates in endosomal compartments in these mutants and leads to light-dependent retinal degeneration. Moreover, we also show that in dying photoreceptors the internalized rhodopsin is not degraded but instead shows characteristics of insoluble proteins. Together these data implicate buildup of rhodopsin in the late endosomal system as a novel trigger of death of photoreceptor neurons. PMID:19214218

  5. Electromagnetic wave equations for relativistically degenerate quantum magnetoplasmas.

    PubMed

    Masood, Waqas; Eliasson, Bengt; Shukla, Padma K

    2010-06-01

    A generalized set of nonlinear electromagnetic quantum hydrodynamic (QHD) equations is derived for a magnetized quantum plasma, including collisional, electron spin- 1/2, and relativistically degenerate electron pressure effects that are relevant for dense astrophysical systems, such as white dwarfs. For illustrative purposes, linear dispersion relations are derived for one-dimensional magnetoacoustic waves for a collisionless nonrelativistic degenerate gas in the presence of the electron spin- 1/2 contribution and for magnetoacoustic waves in a plasma containing relativistically degenerate electrons. It is found that both the spin and relativistic degeneracy at high densities tend to slow down the magnetoacoustic wave due to the Pauli paramagnetic effect and relativistic electron mass increase. The present study outlines the theoretical framework for the investigation of linear and nonlinear behaviors of electromagnetic waves in dense astrophysical systems. The results are applied to calculate the magnetoacoustic speeds for both the nonrelativistic and relativistic electron degeneracy cases typical for white dwarf stars. PMID:20866534

  6. Frontotemporal lobar degeneration: recent progress in antemortem diagnosis.

    PubMed

    Bian, Hong; Grossman, Murray

    2007-07-01

    Frontotemporal lobar degeneration (FTLD) is a neurodegenerative disorder characterized by changes in behaviour and language dysfunction. Two broad pathological subdivisions of FTLD are recognized in a recent classification scheme based on biochemical features: tau-positive pathology due to the accumulation of various forms of the microtubule-associated protein tau, such as FTLD with Pick bodies and corticobasal degeneration; and tau-negative pathology such as frontotemporal lobar degeneration with ubiquitin/TDP-43-immunoreactive inclusions. Etiologically based treatments aim to target the mechanisms underlying the accumulation of these abnormal proteins in these conditions. It is essential for us to develop biomarkers that support the accurate diagnosis of the specific diseases causing FTLD. These biomarkers also can be useful in assessing efficacy during treatment trials. This review summarizes the epidemiologic, clinical, neuropsychological, imaging and cerebrospinal fluid (CSF) biomarker features that can help identify these pathologically defined conditions during life.

  7. Proteoglycan-mediated axon degeneration corrects pretarget topographic sorting errors.

    PubMed

    Poulain, Fabienne E; Chien, Chi-Bin

    2013-04-10

    Proper arrangement of axonal projections into topographic maps is crucial for brain function, especially in sensory systems. An important mechanism for map formation is pretarget axon sorting, in which topographic ordering of axons appears in tracts before axons reach their target, but this process remains poorly understood. Here, we show that selective axon degeneration is used as a correction mechanism to eliminate missorted axons in the optic tract during retinotectal development in zebrafish. Retinal axons are not precisely ordered during initial pathfinding but become corrected later, with missorted axons selectively fragmenting and degenerating. We further show that heparan sulfate is required non-cell-autonomously to correct missorted axons and that restoring its synthesis at late stages in a deficient mutant is sufficient to restore topographic sorting. These findings uncover a function for developmental axon degeneration in ordering axonal projections and identify heparan sulfate as a key regulator of that process. PMID:23583107

  8. Electromagnetic wave equations for relativistically degenerate quantum magnetoplasmas.

    PubMed

    Masood, Waqas; Eliasson, Bengt; Shukla, Padma K

    2010-06-01

    A generalized set of nonlinear electromagnetic quantum hydrodynamic (QHD) equations is derived for a magnetized quantum plasma, including collisional, electron spin- 1/2, and relativistically degenerate electron pressure effects that are relevant for dense astrophysical systems, such as white dwarfs. For illustrative purposes, linear dispersion relations are derived for one-dimensional magnetoacoustic waves for a collisionless nonrelativistic degenerate gas in the presence of the electron spin- 1/2 contribution and for magnetoacoustic waves in a plasma containing relativistically degenerate electrons. It is found that both the spin and relativistic degeneracy at high densities tend to slow down the magnetoacoustic wave due to the Pauli paramagnetic effect and relativistic electron mass increase. The present study outlines the theoretical framework for the investigation of linear and nonlinear behaviors of electromagnetic waves in dense astrophysical systems. The results are applied to calculate the magnetoacoustic speeds for both the nonrelativistic and relativistic electron degeneracy cases typical for white dwarf stars.

  9. Mitochondrial fission augments capsaicin-induced axonal degeneration.

    PubMed

    Chiang, Hao; Ohno, Nobuhiko; Hsieh, Yu-Lin; Mahad, Don J; Kikuchi, Shin; Komuro, Hitoshi; Hsieh, Sung-Tsang; Trapp, Bruce D

    2015-01-01

    Capsaicin, an agonist of transient receptor potential vanilloid receptor 1, induces axonal degeneration of peripheral sensory nerves and is commonly used to treat painful sensory neuropathies. In this study, we investigated the role of mitochondrial dynamics in capsaicin-induced axonal degeneration. In capsaicin-treated rodent sensory axons, axonal swellings, decreased mitochondrial stationary site length and reduced mitochondrial transport preceded axonal degeneration. Increased axoplasmic Ca(2+) mediated the alterations in mitochondrial length and transport. While sustaining mitochondrial transport did not reduce axonal swellings in capsaicin-treated axons, preventing mitochondrial fission by overexpression of mutant dynamin-related protein 1 increased mitochondrial length, retained mitochondrial membrane potentials and reduced axonal loss upon capsaicin treatment. These results establish that mitochondrial stationary site size significantly affects axonal integrity and suggest that inhibition of Ca(2+)-dependent mitochondrial fission facilitates mitochondrial function and axonal survival following activation of axonal cationic channels.

  10. Taurine ameliorates water avoidance stress-induced degenerations of gastrointestinal tract and liver.

    PubMed

    Zeybek, Ali; Ercan, Feriha; Cetinel, Sule; Cikler, Esra; Sağlam, Beyhan; Sener, Göksel

    2006-10-01

    We investigated the role of taurine, is a potent free radical scavenger, on water avoidance stress (WAS)-induced degeneration of the gastric, ileal, and colonic mucosa and liver parenchyma. Wistar albino rats were exposed to chronic WAS (WAS group) 2 hr daily for 5 days. After exposing animals to chronic WAS (WAS + taurine group), 50 mg/kg taurine was injected IP for 3 days. Control animals received vehicle solution only. The stomach, ileum, colon, and liver samples were investigated under light microscope for histopathologic changes. To demonstrate the topography of the luminal mucosa of the stomach, ileum, and colon, scanning electron microscope was used and for hepatocyte ultastructure transmission electron microscope was used. Malondialdehyde (MDA, a biomarker of oxidative damage) and glutathione (GSH, a biomarker of protective oxidative injury) levels were also determined in all tissues. In the WAS group, the stomach epithelium showed ulceration in some areas, dilatations of the gastric glands, and degeneration of gastric glandular cells; prominent congestion of the capillaries was apparent. In the WAS group, severe vascular congestion was observed along with degeneration of ileal and colonic epithelium. Prominent vascular congestion and dilated sinusoids, activated Kupffer cells, dilated granular endoplasmic reticulum membranes, and focal pyknotic nuclei were observed in liver parenchyma. MDA levels (stomach, P < 0.01; ileum, colon, and liver P < 0.05) were increased and GSH levels (P < 0.01) were decreased in all tissues in the WAS group compared with the control group. The morphology of gastric, ileal, and colonic mucosa and liver parenchyma in the WAS + taurine group (stomach and ileum, P < 0.05; colon and liver, P < 0.01) showed a significant amelioration when compared to the WAS group. Increased MDA and decreased GSH levels in the WAS group were ameliorated with taurine treatment. Based on the results, taurine supplementation effectively attenuates the

  11. Trick for passing degenerate points in the Ashtekar formulation

    NASA Astrophysics Data System (ADS)

    Yoneda, Gen; Shinkai, Hisa-Aki; Nakamichi, Akika

    1997-08-01

    We examine one of the advantages of Ashtekar's formulation of general relativity: a tractability of degenerate points from the point of view of following the dynamics of classical spacetime. Assuming that all dynamical variables are finite, we conclude that an essential trick for such a continuous evolution is in complexifying variables. In order to restrict the complex region locally, we propose some ``reality recovering'' conditions on spacetime. Using a degenerate solution derived by a pullback technique, and integrating the dynamical equations numerically, we show that this idea works in an actual dynamical problem. We also discuss some features of these applications.

  12. FOXP2 Expression in Frontotemporal Lobar Degeneration-Tau.

    PubMed

    López-González, Irene; Palmeira, Andre; Aso, Ester; Carmona, Margarita; Fernandez, Liana; Ferrer, Isidro

    2016-09-01

    FOXP2 is altered in a variety of language disorders. We found reduced mRNA and protein expression of FOXP2 in frontal cortex area 8 in Pick's disease, and frontotemporal lobar degeneration-tau linked to P301L mutation presenting with language impairment in comparison with age-matched controls and cases with parkinsonian variant progressive supranuclear palsy. Foxp2 mRNA and protein are also reduced with disease progression in the somatosensory cortex in transgenic mice bearing the P301S mutation in MAPT when compared with wild-type littermates. Our findings support the presence of FOXP2 expression abnormalities in sporadic and familial frontotemporal degeneration tauopathies.

  13. Key emerging issues in progressive supranuclear palsy and corticobasal degeneration

    PubMed Central

    Josephs, Keith A.

    2015-01-01

    It has been approximately 50 years since neurologists were introduced to the entities progressive supranuclear palsy and corticobasal degeneration. Since the two seminal publications, there have been significant advancements in our understanding of these two neurodegenerative diseases, particularly the fact that both are associated with tau. Recent advances over the past 3 years that are notable to the field are discussed in this review that covers clinical diagnosis, pathological features, neuroimaging and CSF biomarkers, genetic associations and clinical trials related to progressive supranuclear palsy and corticobasal degeneration. PMID:25701010

  14. A case of follicular lymphoma associated with paraneoplastic cerebellar degeneration.

    PubMed

    Shimazu, Yayoi; Minakawa, Eiko N; Nishikori, Momoko; Ihara, Masafumi; Hashi, Yuichiro; Matsuyama, Hirofumi; Hishizawa, Masakatsu; Yoshida, Sonoyo; Kitano, Toshiyuki; Kondo, Tadakazu; Ishikawa, Takayuki; Takahashi, Ryosuke; Takaori-Kondo, Akifumi

    2012-01-01

    Paraneoplastic neurological disorders (PND) are neurological effects of malignancy that are recognized as immune-mediated disorders caused by aberrant expression of a tumor antigen that is normally expressed in the nervous system. We report a case of cerebellar ataxia which turned out to be paraneoplastic cerebellar degeneration, a subtype of PND that develops cerebellar symptoms, that was caused by follicular lymphoma. After chemotherapy, the patient attained sufficient improvement of cerebellar symptoms along with complete remission of lymphoma. Paraneoplastic cerebellar degeneration should be recognized as a rare complication of lymphoma as it is important to start proper treatment before the neurological symptoms become irreversible.

  15. Glial fibrillar acidic protein in the cerebrospinal fluid of Alzheimer's disease, dementia with Lewy bodies, and frontotemporal lobar degeneration.

    PubMed

    Ishiki, Aiko; Kamada, Maki; Kawamura, Yuki; Terao, Chiaki; Shimoda, Fumiko; Tomita, Naoki; Arai, Hiroyuki; Furukawa, Katsutoshi

    2016-01-01

    Biomarkers in the cerebrospinal fluid (CSF) are currently regarded as indispensable indicators for accurate differential diagnosis of neurodegenerative disorders. Although high levels of astrocyte-secreted glial fibrillar acidic protein (GFAP) in the CSF of patients with Alzheimer's disease (AD) have been reported, the levels of GFAP in the CSF have not been fully investigated in other neurological disorders that cause dementia, such as dementia with Lewy bodies (DLB) and frontotemporal lobar degeneration (FTLD). In this study, we determined the levels of GFAP in the CSF of healthy control subjects and AD, DLB, and FTLD patients to address two questions: (i) Do the levels of GFAP differ among these disorders? and (ii) Can GFAP be used as a biomarker for the differential diagnosis of these neurodegenerative disorders? The levels of GFAP in AD, DLB, and FTLD patients were significantly higher than those in the healthy control subjects. Although the levels of GFAP were not significantly different between AD and DLB patients, a higher level of GFAP was observed in FTLD patients than in AD and DLB patients. It is concluded that representative neurological disorders causing dementia were associated with higher levels of GFAP in the CSF. We propose the following mechanism concerning the amount of glial fibrillar acidic protein (GFAP) in the cerebrospinal fluid (CSF) in Alzheimer's disease (AD), dementia with Lewy bodies (DLB), and frontotemporal lobar degeneration (FTLD). The increase in the release of GFAP into CSF is considered to reflect the sum of degeneration of astrocytes and astrocytosis. The sum of degeneration and astrocytosis or the GFAP release could be in the order of FTLD > DLB > AD > normal condition.

  16. 12. VIEW LOOKING WEST FROM THE PARKING LOT ADJACENT TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. VIEW LOOKING WEST FROM THE PARKING LOT ADJACENT TO THE STEEL PLANT OFFICES. BAR AND BILLET MILLS AND, IN THE DISTANCE, THE BASIC OXYGEN FURNACES MAY BE SEEN. - Corrigan, McKinney Steel Company, 3100 East Forty-fifth Street, Cleveland, Cuyahoga County, OH

  17. 8. Exterior view, showing tank and associated piping adjacent to ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Exterior view, showing tank and associated piping adjacent to Test Cell 6, Systems Integration Laboratory Building (T-28), looking south. - Air Force Plant PJKS, Systems Integration Laboratory, Systems Integration Laboratory Building, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

  18. 10. Detail and contextual view of bridge and adjacent farmstead ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Detail and contextual view of bridge and adjacent farmstead setting. Note laced vertical compression members, latticed portal strut, decorative strut bracing, and lightness of diagonal and lateral tension members. View to southeast through southeast portal from truss mid-span. - Red Bank Creek Bridge, Spanning Red Bank Creek at Rawson Road, Red Bluff, Tehama County, CA

  19. 11. Interior detail, Boiler Room, fire door to the adjacent ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Interior detail, Boiler Room, fire door to the adjacent Blacksmith Shop, Roundhouse Machine Shop Extension, Southern Pacific Railroad Carlin Shops, view to southwest (90mm lens). - Southern Pacific Railroad, Carlin Shops, Roundhouse Machine Shop Extension, Foot of Sixth Street, Carlin, Elko County, NV

  20. 1. VIEW FROM SOUTHWEST SHOWING SOUTH (FRONT) ELEVATION, ADJACENT LOUGHRAN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. VIEW FROM SOUTHWEST SHOWING SOUTH (FRONT) ELEVATION, ADJACENT LOUGHRAN BUILDING (BASSIN'S RESTAURANT) (HABS No. DC-357), 501-511 14TH STREET (THE LOCKER ROOM) HABS No. DC-356) ON CORNER, AND MUNSEY BUILDING (HABS No. DC-358) - William J. Stone Building, 1345 E Street Northwest, Washington, District of Columbia, DC

  1. VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING RECREATION AREA AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING RECREATION AREA AND ENTRY TO NEIGHBORHOOD. VIEW FACING SOUTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  2. VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING INTERSECTION OF ACACIA ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING INTERSECTION OF ACACIA ROAD WITH BIRCH CIRCLE. VIEW FACING NORTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  3. VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING RECREATION AREA ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING RECREATION AREA ON RIGHT, AND HOUSING AREA ON LEFT. VIEW FACING EAST/NORTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  4. VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING WESTERN SIDE OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW FROM ATOP ADJACENT RESIDENTIAL TOWER, SHOWING WESTERN SIDE OF NEIGHBORHOOD. VIEW FACING NORTHWEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  5. 1. OVERVIEW SHOWING FIRING CONTROL BLOCKHOUSE 0502 AND ADJACENT OBSERVATION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. OVERVIEW SHOWING FIRING CONTROL BLOCKHOUSE 0502 AND ADJACENT OBSERVATION TOWER. WATER BRAKE TROUGH SEGMENT AT LOWER RIGHT. Looking north northeast. - Edwards Air Force Base, South Base Sled Track, Firing & Control Blockhouse for 10,000-foot Track, South of Sled Track at midpoint of 20,000-foot track, Lancaster, Los Angeles County, CA

  6. 7. VIEW OF WATER TREATMENT PLANT, ADJACENT TO THE COAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW OF WATER TREATMENT PLANT, ADJACENT TO THE COAL CONVEYOR; IN THE DISTANCE IS THE FREQUENCY CHANGER HOUSE, WHICH IS ATTACHED TO SWITCH HOUSE NO. 1; LOOKING WEST. - Commonwealth Electric Company, Fisk Street Electrical Generating Station, 1111 West Cermak Avenue, Chicago, Cook County, IL

  7. 4. REAR ELEVATION, DETAIL OF CONSTRUCTION, ADJACENT CORNER POSTS BETWEEN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. REAR ELEVATION, DETAIL OF CONSTRUCTION, ADJACENT CORNER POSTS BETWEEN BUILDING PERIODS 1 AND 3. NOTE REUSED WOOD STRIP NAILED TO BUILDING PERIOD 1 POST INSCRIBED 'ST. LEONARD'. THERE ARE NO NAIL HOLES IN THE PERIOD 3 POST, THE FARRING STRIPS ADJUST FOR CLADDING - Charles' Gift, State Routes 2 & 4, Lusby, Calvert County, MD

  8. Biogeochemistry of hydrothermally and adjacent non-altered soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As a field/lab project, students in the Soil Biogeochemistry class of the University of Nevada, Reno described and characterized seven pedons, developed in hydrothermally and adjacent non-hydrothermally altered andesitic parent material near Reno, NV. Hydrothermally altered soils had considerably lo...

  9. 12. LOG FOUNDATION ELEMENTS OF THE SAWMILL ADJACENT TO THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. LOG FOUNDATION ELEMENTS OF THE SAWMILL ADJACENT TO THE CANAL, LOOKING EAST. BARREN AREA IN FOREGROUND IS DECOMPOSING SAWDUST. DIRT PILE IN BACKGROUND IS THE EDGE OF THE SUMMIT COUNTY LANDFILL. - Snake River Ditch, Headgate on north bank of Snake River, Dillon, Summit County, CO

  10. LEHR NO. 2 AND LEHR NO. 3 ADJACENT TO FURNACE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    LEHR NO. 2 AND LEHR NO. 3 ADJACENT TO FURNACE ROOM; THE PIPES AT THE BOTTOM ARE PART OF THE RADIANT HEATING SYSTEM USED FOR HEATING THE FACTORY DURING COLD WEATHER. - Westmoreland Glass Company, Seventh & Kier Streets, Grapeville, Westmoreland County, PA

  11. How subaerial salt extrusions influence water quality in adjacent aquifers

    NASA Astrophysics Data System (ADS)

    Mehdizadeh, Razieh; Zarei, Mehdi; Raeisi, Ezzat

    2015-12-01

    Brines supplied from salt extrusions cause significant groundwater salinization in arid and semi-arid regions where salt rock is exposed to dissolution by episodic rainfalls. Here we focus on 62 of the 122 diapirs of Hormuz salt emergent in the southern Iran. To consider managing the degradation effect that salt extrusions have on the quality of adjoining aquifers, it is first necessary to understand how they influence adjacent water resources. We evaluate here the impacts that these diapirs have on adjacent aquifers based on investigating their geomorphologies, geologies, hydrologies and hydrogeologies. The results indicate that 28/62 (45%) of our sample of salt diapirs have no significant impact on the quality of groundwater in adjoining aquifers (namely Type N), while the remaining 34/62 (55%) degrade nearby groundwater quality. We offer simple conceptual models that account for how brines flowing from each of these types of salt extrusions contaminate adjacent aquifers. We identify three main mechanisms that lead to contamination: surface impact (Type A), subsurface intrusion (Type B) and indirect infiltration (Type C). A combination of all these mechanisms degrades the water quality in nearby aquifers in 19/62 (31%) of the salt diapirs studied. Having characterized the mechanism(s) by which each diapir affects the adjacent aquifer, we suggest a few possible remediation strategies to be considered. For instance, engineering the surface runoff of diapirs Types A and C into nearby evaporation basins would improve groundwater quality.

  12. Hsp90 inhibition protects against inherited retinal degeneration

    PubMed Central

    Aguilà, Mònica; Bevilacqua, Dalila; McCulley, Caroline; Schwarz, Nele; Athanasiou, Dimitra; Kanuga, Naheed; Novoselov, Sergey S.; Lange, Clemens A.K.; Ali, Robin R.; Bainbridge, James W.; Gias, Carlos; Coffey, Peter J.; Garriga, Pere; Cheetham, Michael E.

    2014-01-01

    The molecular chaperone Hsp90 is important for the functional maturation of many client proteins, and inhibitors are in clinical trials for multiple indications in cancer. Hsp90 inhibition activates the heat shock response and can improve viability in a cell model of the P23H misfolding mutation in rhodopsin that causes autosomal dominant retinitis pigmentosa (adRP). Here, we show that a single low dose of the Hsp90 inhibitor HSP990 enhanced visual function and delayed photoreceptor degeneration in a P23H transgenic rat model. This was associated with the induction of heat shock protein expression and reduced rhodopsin aggregation. We then investigated the effect of Hsp90 inhibition on a different type of rod opsin mutant, R135L, which is hyperphosphorylated, binds arrestin and disrupts vesicular traffic. Hsp90 inhibition with 17-AAG reduced the intracellular accumulation of R135L and abolished arrestin binding in cells. Hsf-1−/− cells revealed that the effect of 17-AAG on P23H aggregation was dependent on HSF-1, whereas the effect on R135L was HSF-1 independent. Instead, the effect on R135L was mediated by a requirement of Hsp90 for rhodopsin kinase (GRK1) maturation and function. Importantly, Hsp90 inhibition restored R135L rod opsin localization to wild-type (WT) phenotype in vivo in rat retina. Prolonged Hsp90 inhibition with HSP990 in vivo led to a posttranslational reduction in GRK1 and phosphodiesterase (PDE6) protein levels, identifying them as Hsp90 clients. These data suggest that Hsp90 represents a potential therapeutic target for different types of rhodopsin adRP through distinct mechanisms, but also indicate that sustained Hsp90 inhibition might adversely affect visual function. PMID:24301679

  13. Progesterone neuroprotection in traumatic CNS injury and motoneuron degeneration.

    PubMed

    De Nicola, Alejandro F; Labombarda, Florencia; Gonzalez Deniselle, Maria Claudia; Gonzalez, Susana L; Garay, Laura; Meyer, Maria; Gargiulo, Gisella; Guennoun, Rachida; Schumacher, Michael

    2009-07-01

    Studies on the neuroprotective and promyelinating effects of progesterone in the nervous system are of great interest due to their potential clinical connotations. In peripheral neuropathies, progesterone and reduced derivatives promote remyelination, axonal regeneration and the recovery of function. In traumatic brain injury (TBI), progesterone has the ability to reduce edema and inflammatory cytokines, prevent neuronal loss and improve functional outcomes. Clinical trials have shown that short-and long-term progesterone treatment induces a significant improvement in the level of disability among patients with brain injury. In experimental spinal cord injury (SCI), molecular markers of functional motoneurons become impaired, including brain-derived neurotrophic factor (BDNF) mRNA, Na,K-ATPase mRNA, microtubule-associated protein 2 and choline acetyltransferase (ChAT). SCI also produces motoneuron chromatolysis. Progesterone treatment restores the expression of these molecules while chromatolysis subsided. SCI also causes oligodendrocyte loss and demyelination. In this case, a short progesterone treatment enhances proliferation and differentiation of oligodendrocyte progenitors into mature myelin-producing cells, whereas prolonged treatment increases a transcription factor (Olig1) needed to repair injury-induced demyelination. Progesterone neuroprotection has also been shown in motoneuron neurodegeneration. In Wobbler mice spinal cord, progesterone reverses the impaired expression of BDNF, ChAT and Na,K-ATPase, prevents vacuolar motoneuron degeneration and the development of mitochondrial abnormalities, while functionally increases muscle strength and the survival of Wobbler mice. Multiple mechanisms contribute to these progesterone effects, and the role played by classical nuclear receptors, extra nuclear receptors, membrane receptors, and the reduced metabolites of progesterone in neuroprotection and myelin formation remain an exciting field worth of exploration

  14. OBSERVATIONAL CONSTRAINTS ON THE DEGENERATE MASS-RADIUS RELATION

    SciTech Connect

    Holberg, J. B.; Oswalt, T. D.; Barstow, M. A. E-mail: toswalt@fit.edu

    2012-03-15

    The white dwarf mass-radius relationship is fundamental to modern astrophysics. It is central to routine estimation of DA white dwarf masses derived from spectroscopic temperatures and gravities. It is also the basis for observational determinations of the white dwarf initial-final-mass relation. Nevertheless, definitive and detailed observational confirmations of the mass-radius relation (MRR) remain elusive owing to a lack of sufficiently accurate white dwarf masses and radii. Current best estimates of masses and radii allow only broad conclusions about the expected inverse relation between masses and radii in degenerate stars. In this paper, we examine a restricted set of 12 DA white dwarf binary systems for which accurate (1) trigonometric parallaxes, (2) spectroscopic effective temperatures and gravities, and (3) gravitational redshifts are available. We consider these three independent constraints on mass and radius in comparison with an appropriate evolved MRR for each star. For the best-determined systems it is found that the DA white dwarfs conform to evolve theoretical MRRs at the 1{sigma} to 2{sigma} level. For the white dwarf 40 Eri B (WD 0413-077) we find strong evidence for the existence of a 'thin' hydrogen envelope. For other stars improved parallaxes will be necessary before meaningful comparisons are possible. For several systems current parallaxes approach the precision required for the state-of-the-art mass and radius determinations that will be obtained routinely from the Gaia mission. It is demonstrated here how these anticipated results can be used to firmly constrain details of theoretical mass-radius determinations.

  15. Degeneration of axons in spinal white matter in G93A mSOD1 mouse characterized by NFL and α-internexin immunoreactivity.

    PubMed

    King, Anna E; Blizzard, Catherine A; Southam, Katherine A; Vickers, James C; Dickson, Tracey C

    2012-07-17

    Axonal degeneration is a prominent feature of amyotrophic lateral sclerosis (ALS) both in lower motor nerves as well as descending white matter axons in the spinal cord of human patients. Although the pathology of lower motor axonal degeneration has been described in both human ALS and related transgenic animal models, few studies have examined the pathological features of descending axon degeneration, particularly in mouse models of ALS. We have examined the degeneration of white matter tracts in the G93A mutant superoxide dismutase-1 (mSOD1+) mouse spinal cord white matter from 12 weeks of age to end-stage disease. In a G93A mSOD1 mouse model where green fluorescent protein was expressed in neurons (mSOD1+/GFP+), degeneration of white matter tracts was present from the ventral to dorsolateral funiculi. This pattern of axonal pathology occurred from 16 weeks of age. However, the dorsal funiculus, the site of the major corticospinal tract in mice, showed relatively less degeneration. Immunohistochemical analysis demonstrated that the neurofilament light chain (NFL) and neuronal intermediate filament protein alpha-internexin accumulated in axon swellings in the spinal white matter. Increased levels of alpha-internexin protein, in mSOD1+ mouse spinal cord tissue, were demonstrated by Western blotting. In contrast, degenerating axons did not show obvious accumulations of neurofilament medium and heavy chain proteins (NFM and NFH). These data suggest that white matter degeneration in this mouse model of ALS is widespread and involves a specific molecular signature, particularly the accumulation of NFL and alpha-internexin proteins.

  16. Sudden death while driving. Role of sinus perinodal degeneration and cardiac neural degeneration and ganglionitis.

    PubMed

    James, T N; Pearce, W N; Givhan, E G

    1980-05-01

    A young business executive was seen to slump over his steering wheel while driving, after which the automobile veered and turned over. Quickly taken unconscious to a nearby emergency room, he was pronounced dead on arrival. Because there was insufficient physical injury found to account for his death, and because atrial fibrillation had been detected for the first time on a routine physical examination 3 months previously, special examination of the cardiac conduction system was performed. A fibroma was present on the right side of the central fibrous body above the His bundle, similar to several fibromas on the mitral valve. Small foci of neuritis were present in the ventricular myocardium and the atrioventricular node. More extensive neural degeneration and ganglionitis were found near the sinus node, which also exhibited an encircling perinodal fibrosis. Ways in which these abnormalities could have caused a fatal electrical instability of the heart are discussed. Careful examination of the cardiac conduction system is warranted in other fatal automobile accidents under similar circumstances.

  17. Does lumbar paraspinal muscle fatty degeneration correlate with aerobic index and Oswestry disability index?

    PubMed Central

    Prasarn, Mark L.; Kostantinos, Vasalos; Coyne, Ellen; Wright, John; Rechtine, Glenn R.

    2015-01-01

    Background: We sought to analyze whether the amount of paraspinal fatty degeneration correlates with a patient's physical fitness, and to determine if these findings on lumbar magnetic resonance imaging (MRI) scans can help predict functional outcomes. Methods: A retrospective review was performed on 172 patients. Inclusion criteria involved being seen by a spine surgeon for low back pain, having aerobic index (AI), body mass index (BMI), Oswestry disability index (ODI), and body fat percentage measured recently, and having had a recent lumbar MRI scan. The percentage of fatty muscle degeneration was graded by three reviewers using T2-weighted axial images at L3 and L5 using a newly proposed system that was validated independently. The system is graded as follows: Grade 1: 0-24%, Grade 2: 25-49%, Grade 3: 50-74%, and Grade 4: 75-100%. An independent t-test was used for comparisons. Results: The average AI was 34.87, and the cohort was divided into two groups: above-average AI (89 patients) and below-average AI (83 patients). For all paraspinal fat measurements and body fat percentage, the difference between the above- and below-average AI groups was statistically significant (P < 0.05), with the least amount of paraspinal fatty degeneration and body fat in the greater AI group. Weight alone and BMI were not found to be significantly different between those with above-average AI when compared to those with below-average AI (P = 0.491 and P = 0.122, respectively). There was a trend for lower ODI scores in the above-average AI group (41.9 vs 46.1), but this did not reach statistical significance between the two groups (P = 0.075). For all patients it was shown that there was significantly less paraspinal fat at the L3 level as compared to L5 (P < 0.001). Conclusions: We were able to show that patients with a higher AI have lower body fat percentages and lower amounts of fatty degeneration in their lumbar paraspinal musculature. The amount of paraspinal fatty

  18. Mortality of passerines adjacent to a North Carolina corn field treated with granular carbofuran.

    USGS Publications Warehouse

    Augspurger, Tom; Smith, Milton R.; Meteyer, Carol U.; Converse, Kathryn A.

    1996-01-01

    Red-winged blackbirds (Agelaius phoeniceus) were collected during an epizootic in southeastern North Carolina (USA). Activity of brain cholinesterase (ChE) was inhibited by 14 to 48% in three of five specimens, and returned to normal levels after incubation. Gastrointestinal tracts were analyzed for 30 anti-ChE agents. Carbofuran, the only compound detected, was present in all specimens at levels from 5.44 to 72.7 μg/g wet weight. Application of granular carbofuran in an adjacent corn field, results of necropsy examinations, and chemical analyses are consistent with a diagnosis of carbofuran poisoning in these specimens.

  19. The calculation of adjacent satellite interference for direct broadcast satellite systems

    NASA Astrophysics Data System (ADS)

    Dewell, R.; Siddiqi, S.

    1987-10-01

    In order to coordinate present and future in-orbit broadcast satellite systems, orbital slots and operating frequency bands must be allocated in such a way that the available broadcast spectrum is fully used, while the lowest level of interference between systems is maintained. The considerations affecting system planning and the factors determining broadcast transmission quality are reviewed, and a practical broadcast satellite system example is described. Copolarized and cross-polarized interfering signals are discussed, and the evaluation of received, cross-polarized, interfering power is considered. The calculation of minimum and maximum interference levels is addressed, and the acceptance criterion for adjacent-channel interference is discussed.

  20. High Prevalence of Disc Degeneration and Spondylolysis in the Lumbar Spine of Professional Beach Volleyball Players

    PubMed Central

    Külling, Fabrice A.; Florianz, Hannes; Reepschläger, Bastian; Gasser, Johann; Jost, Bernhard; Lajtai, Georg

    2014-01-01

    Background: Beach volleyball is an intensive sport with high impact on the lumbar spine. Low back pain (LBP) is frequent among elite players. Increased prevalence of pathological changes on magnetic resonance imaging (MRI) in the lumbar spine of elite athletes has been reported. Hypothesis: There is an increased prevalence of disc degeneration and spondylolysis in the MRI of the lumbar spine of professional beach volleyball players. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Twenty-nine fully competitive professional male volleyball players (mean age, 28 years) completed outcomes questionnaires and underwent a complete clinical examination and an MRI of their lumbar spine. Results: Whereas 86% of players suffered from LBP during their career, the incidence of LBP in the last 4 weeks was 35%. Pain rated using a visual analog scale (VAS) averaged 3 points (range, 0-8). Twenty-three of 29 players (79%) had at least 1 degenerated disc of Pfirrmann grade ≥3. The most affected spinal levels were L4-5 in 14 (48%) and L5-S1 in 15 players (52%); both levels were involved in 5 players (17%). Six of 29 (21%) players showed a spondylolysis grade 4 according to the Hollenburg classification; there was evidence of spondylolisthesis in 2 players. There was no significant correlation between LBP and MRI abnormalities. Conclusion: In the lumbar spine MRI of professional beach volleyball players, the prevalence of disc degeneration is 79%. Spondylolysis (21%) is up to 3 times higher compared with the normal population. Abnormal MRI findings did not correlate with LBP, thus MRIs have to be interpreted with caution. PMID:26535316

  1. Ccl2, Cx3cr1 and Ccl2/Cx3cr1 chemokine deficiencies are not sufficient to cause age-related retinal degeneration.

    PubMed

    Luhmann, Ulrich F O; Carvalho, Livia S; Robbie, Scott J; Cowing, Jill A; Duran, Yanai; Munro, Peter M G; Bainbridge, James W B; Ali, Robin R

    2013-02-01

    Monocytes, macrophages, dendritic cells and microglia play critical roles in the local immune response to acute and chronic tissue injury and have been implicated in the pathogenesis of age-related macular degeneration. Defects in Ccl2-Ccr2 and Cx3cl1-Cx3cr1 chemokine signalling cause enhanced accumulation of bloated subretinal microglia/macrophages in senescent mice and this phenomenon is reported to result in the acceleration of age-related retinal degeneration. The purpose of this study was to determine whether defects in CCL2-CCR2 and CX3CL1-CX3CR1 signalling pathways, alone or in combination, cause age-dependent retinal degeneration. We tested whether three chemokine knockout mouse lines, Ccl2(-/-), Cx3cr1(-/-) and Ccl2(-/-)/Cx3cr1(-/-), in comparison to age-matched C57Bl/6 control mice show differences in subretinal macrophage accumulation and loss of adjacent photoreceptor cells at 12-14 months of age. All mouse lines are derived from common parental strains and do not carry the homozygous rd8 mutation in the Crb1 gene that has been a major confounding factor in previous reports. We quantified subretinal macrophages by counting autofluorescent lesions in fundus images obtained by scanning laser ophthalmoscopy (AF-SLO) and by immunohistochemistry for Iba1 positive cells. The accumulation of subretinal macrophages was enhanced in Ccl2(-/-), but not in Cx3cr1(-/-) or Ccl2(-/-)/Cx3cr1(-/-) mice. We identified no evidence of retinal degeneration in any of these mouse lines by TUNEL staining or semithin histology. In conclusion, CCL2-CCR2 and/or CX3CL1-CX3CR1 signalling defects may differentially affect the trafficking of microglia and macrophages in the retina during ageing, but do not appear to cause age-related retinal degeneration in mice.

  2. NMNAT1 inhibits axon degeneration via blockade of SARM1-mediated NAD+ depletion

    PubMed Central

    Sasaki, Yo; Nakagawa, Takashi; Mao, Xianrong; DiAntonio, Aaron; Milbrandt, Jeffrey

    2016-01-01

    Overexpression of the NAD+ biosynthetic enzyme NMNAT1 leads to preservation of injured axons. While increased NAD+ or decreased NMN levels are thought to be critical to this process, the mechanism(s) of this axon protection remain obscure. Using steady-state and flux analysis of NAD+ metabolites in healthy and injured mouse dorsal root ganglion axons, we find that rather than altering NAD+ synthesis, NMNAT1 instead blocks the injury-induced, SARM1-dependent NAD+ consumption that is central to axon degeneration. DOI: http://dx.doi.org/10.7554/eLife.19749.001 PMID:27735788

  3. The role of glial cells and the complement system in retinal diseases and Alzheimer's disease: common neural degeneration mechanisms.

    PubMed

    Harvey, Hannah; Durant, Szonya

    2014-11-01

    Many age-related degenerative diseases of the central nervous system (CNS) increasingly appear to have similarities in their underlying causes. By applying knowledge between disorders, and in particular between degenerative diseases of different components of the CNS (e.g. the eye and the brain), we can begin to elucidate general mechanisms of neural degeneration. Age-related macular degeneration and glaucoma, two diseases of retinal neurons, which have recently been discussed in view of their common mechanisms with Alzheimer's disease, highlight this perspective. This review discusses the common roles of the complement system (an immunological system) and glial cells (providing, amongst other functions, trophic support to neurons) in these three disorders. A number of facets of these systems would seem to be involved in the mechanisms of degeneration in at least two of the three diseases considered here. Regulatory proteins of the complement system (such as factor H), neurotrophin levels, and the interaction of microglia with the complement system in particular may be general to all three presentations of neural degeneration. Investigating the functioning of these fundamental systems across different diseases exemplifies the importance of considering advances in knowledge across a wider base than specific disease pathology. This may give insights both for understanding the function of these supporting systems and providing an avenue for developing future therapeutic targets general to neural degenerative diseases.

  4. Sphingolipid profile alters in retinal dystrophic P23H-1 rats and systemic FTY720 can delay retinal degeneration.

    PubMed

    Stiles, Megan; Qi, Hui; Sun, Eleanor; Tan, Jeremy; Porter, Hunter; Allegood, Jeremy; Chalfant, Charles E; Yasumura, Douglas; Matthes, Michael T; LaVail, Matthew M; Mandal, Nawajes A

    2016-05-01

    Retinal degeneration (RD) affects millions of people and is a major cause of ocular impairment and blindness. With a wide range of mutations and conditions leading to degeneration, targeting downstream processes is necessary for developing effective treatments. Ceramide and sphingosine-1-phosphate, a pair of bioactive sphingolipids, are involved in apoptosis and its prevention, respectively. Apoptotic cell death is a potential driver of RD, and in order to understand the mechanism of degeneration and potential treatments, we studied rhodopsin mutant RD model, P23H-1 rats. Investigating this genetic model of human RD allows us to investigate the association of sphingolipid metabolites with the degeneration of the retina in P23H-1 rats and the effects of a specific modulator of sphingolipid metabolism, FTY720. We found that P23H-1 rat retinas had altered sphingolipid profiles that, when treated with FTY720, were rebalanced closer to normal levels. FTY720-treated rats also showed protection from RD compared with their vehicle-treated littermates. Based on these data, we conclude that sphingolipid dysregulation plays a secondary role in retinal cell death, which may be common to many forms of RDs, and that the U.S. Food and Drug Administration-approved drug FTY720 or related compounds that modulate sphingolipid metabolism could potentially delay the cell death. PMID:26947037

  5. Cesare Lombroso: an anthropologist between evolution and degeneration

    PubMed Central

    Mazzarello, Paolo

    Summary Cesare Lombroso (1835–1909) was a prominent Italian medical doctor and intellectual in the second half of the nineteenth century. He became world famous for his theory that criminality, madness and genius were all sides of the same psychobiological condition: an expression of degeneration , a sort of regression along the phylogenetic scale, and an arrest at an early stage of evolution. Degeneration affected criminals especially, in particular the “born delinquent” whose development had stopped at an early stage, making them the most “atavistic” types of human being. Lombroso also advocated the theory that genius was closely linked with madness. A man of genius was a degenerate, an example of retrograde evolution in whom madness was a form of “biological compensation” for excessive intellectual development. To confirm this theory, in August 1897, Lombroso, while attending the Twelfth International Medical Congress in Moscow, decided to meet the great Russian writer Lev Tolstoy in order to directly verify, in him, his theory of degeneration in the genius. Lombroso’s anthropological ideas fuelled a heated debate on the biological determinism of human behaviour. PMID:21729591

  6. Electron–ion relaxation time in moderately degenerate plasma

    SciTech Connect

    Vronskii, M. A. Koryakina, Yu. V.

    2015-09-15

    A formula is derived for the electron–ion relaxation time in a partially degenerate plasma with electron-ion interaction via a central field. The resulting expression in the form of an integral of the transport cross section generalizes the well-known Landau and Brysk approximations.

  7. Anisotropic uniqueness classes for a degenerate parabolic equation

    SciTech Connect

    Vil'danova, V F; Mukminov, F Kh

    2013-11-30

    Anisotropic uniqueness classes of Tacklind type are identified for a degenerate linear parabolic equation of the second order in an unbounded domain. The Cauchy problem and mixed problems with boundary conditions of the first and third type are considered. Bibliography: 18 titles.

  8. Therapeutic Approaches to Histone Reprogramming in Retinal Degeneration.

    PubMed

    Berner, Andre K; Kleinman, Mark E

    2016-01-01

    Recent data have revealed epigenetic derangements and subsequent chromatin remodeling as a potent biologic switch for chronic inflammation and cell survival which are important therapeutic targets in the pathogenesis of several retinal degenerations. Histone deacetylases (HDACs) are a major component of this system and serve as a unique control of the chromatin remodeling process. With a multitude of targeted HDAC inhibitors now available, their use in both basic science and clinical studies has widened substantially. In the field of ocular biology, there are data to suggest that HDAC inhibition may suppress neovascularization and may be a possible treatment for retinitis pigmentosa and dry age-related macular degeneration (AMD). However, the effects of these inhibitors on cell survival and chemokine expression in the chorioretinal tissues remain very unclear. Here, we review the multifaceted biology of HDAC activity and pharmacologic inhibition while offering further insight into the importance of this epigenetic pathway in retinal degenerations. Our laboratory investigations aim to open translational avenues to advance dry AMD therapeutics while exploring the role of acetylation on inflammatory gene expression in the aging and degenerating retina. PMID:26427391

  9. The Experience of Age-Related Macular Degeneration

    ERIC Educational Resources Information Center

    Wong, Elaine Y. H.; Guymer, Robyn H.; Hassell, Jennifer B.; Keeffe, Jill E.

    2004-01-01

    This qualitative article describes the impact of age-related macular degeneration (ARMD) among 15 participants: how a person makes sense of ARMD, the effect of ARMD on the person's quality of life, the psychological disturbances associated with the limitations of ARMD, and the influence of ARMD on social interactions. Such in-depth appreciation of…

  10. Dystonia and Cerebellar Degeneration in the Leaner Mouse Mutant

    PubMed Central

    Raike, Robert S.; Hess, Ellen J.; Jinnah, H.A.

    2015-01-01

    Cerebellar degeneration is traditionally associated with ataxia. Yet, there are examples of both ataxia and dystonia occurring in individuals with cerebellar degeneration. There is also substantial evidence suggesting that cerebellar dysfunction alone may cause dystonia. The types of cerebellar defects that may cause ataxia, dystonia, or both have not been delineated. In the current study, we explored the relationship between cerebellar degeneration and dystonia using the leaner mouse mutant. Leaner mice have severe dystonia that is associated with dysfunctional and degenerating cerebellar Purkinje cells. Whereas the density of Purkinje cells was not significantly reduced in 4 week-old leaner mice, approximately 50% of the neurons were lost by 34 weeks of age. On the other hand, the dystonia and associated functional disability became significantly less severe during this same interval. In other words, dystonia improved as Purkinje cells were lost, suggesting that dysfunctional Purkinje cells, rather than Purkinje cell loss, contribute to the dystonia. These results provide evidence that distorted cerebellar function may cause dystonia and support the concept that different types of cerebellar defects can have different functional consequences. PMID:25791619

  11. Speech and Language Findings Associated with Paraneoplastic Cerebellar Degeneration

    ERIC Educational Resources Information Center

    Paslawski, Teresa; Duffy, Joseph R.; Vernino, Steven

    2005-01-01

    Paraneoplastic cerebellar degeneration (PCD) is an autoimmune disease that can be associated with cancer of the breast, lung, and ovary. The clinical presentation of PCD commonly includes ataxia, visual disturbances, and dysarthria. The speech disturbances associated with PCD have not been well characterized, despite general acceptance that…

  12. Spectral analysis of linear relations and degenerate operator semigroups

    SciTech Connect

    Baskakov, A G; Chernyshov, K I

    2002-12-31

    Several problems of the spectral theory of linear relations in Banach spaces are considered. Linear differential inclusions in a Banach space are studied. The construction of the phase space and solutions is carried out with the help of the spectral theory of linear relations, ergodic theorems, and degenerate operator semigroups.

  13. Microsphere embolization of nerve capillaries and fiber degeneration.

    PubMed Central

    Nukada, H.; Dyck, P. J.

    1984-01-01

    Polystyrene microspheres, the size chosen to plug capillaries and precapillaries, were injected into the arterial supply of rat sciatic nerves. They produced widespread segmental occlusion of capillaries in lower limb nerves. The clinical and pathologic effect was dose-related. One million microspheres produced selective capillary occlusion but no nerve fiber degeneration; approximately 6 million microspheres also produced selective capillary occlusion and associated foot and leg weakness, sensory loss, and fiber degeneration, beginning in a central core of the distal sciatic nerve; 30 million microspheres caused both capillary and arterial occlusion and a greater neuropathologic deficit. From these observations it is inferred that 1) occlusion of isolated precapillaries and capillaries does not produce ischemic fiber degeneration; 2) occlusion of many microvessels results in central fascicular fiber degeneration, indicating that these cores are watershed regions of poor perfusion; and 3) stereotyped pathologic alterations of nerve fibers and Schwann cells are related to dose, anatomic site, and time elapsed since injection. Images Figure 1 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 PMID:6326580

  14. Exact null controllability of degenerate evolution equations with scalar control

    SciTech Connect

    Fedorov, Vladimir E; Shklyar, Benzion

    2012-12-31

    Necessary and sufficient conditions for the exact null controllability of a degenerate linear evolution equation with scalar control are obtained. These general results are used to examine the exact null controllability of the Dzektser equation in the theory of seepage. Bibliography: 13 titles.

  15. Microglial phagocytosis of living photoreceptors contributes to inherited retinal degeneration

    PubMed Central

    Zhao, Lian; Zabel, Matthew K; Wang, Xu; Ma, Wenxin; Shah, Parth; Fariss, Robert N; Qian, Haohua; Parkhurst, Christopher N; Gan, Wen-Biao; Wong, Wai T

    2015-01-01

    Retinitis pigmentosa, caused predominantly by mutations in photoreceptor genes, currently lacks comprehensive treatment. We discover that retinal microglia contribute non-cell autonomously to rod photoreceptor degeneration by primary phagocytosis of living rods. Using rd10 mice, we found that the initiation of rod degeneration is accompanied by early infiltration of microglia, upregulation of phagocytic molecules in microglia, and presentation of “eat-me” signals on mutated rods. On live-cell imaging, infiltrating microglia interact dynamically with photoreceptors via motile processes and engage in rapid phagocytic engulfment of non-apoptotic rods. Microglial contribution to rod demise is evidenced by morphological and functional amelioration of photoreceptor degeneration following genetic ablation of retinal microglia. Molecular inhibition of microglial phagocytosis using the vitronectin receptor antagonist cRGD also improved morphological and functional parameters of degeneration. Our findings highlight primary microglial phagocytosis as a contributing mechanism underlying cell death in retinitis pigmentosa and implicate microglia as a potential cellular target for therapy. PMID:26139610

  16. Advancing Research and Treatment for Frontotemporal Lobar Degeneration (ARTFL)

    ClinicalTrials.gov

    2016-04-29

    FTLD; Progressive Supranuclear Palsy (PSP); Frontotemporal Dementia (FTD); Corticobasal Degeneration (CBD); PPA Syndrome; Behavioral Variant Frontotemporal Dementia (bvFTD); Semantic Variant Primary Progressive Aphasia (svPPA); Nonfluent Variant Primary Progressive Aphasia (nfvPPA); FTD With Amyotrophic Lateral Sclerosis (FTD/ALS); Amyotrophic Lateral Sclerosis (ALS); Oligosymptomatic PSP (oPSP); Corticobasal Syndrome (CBS)

  17. Diffuse thalamic degeneration in fatal familial insomnia. A morphometric study.

    PubMed

    Macchi, G; Rossi, G; Abbamondi, A L; Giaccone, G; Mancia, D; Tagliavini, F; Bugiani, O

    1997-10-10

    A morphometric investigation disclosed most thalamic nuclei severely degenerated in two patients with fatal familial insomnia. Associative and motor nuclei lost 90% neurons, and limbic-paralimbic, intralaminar and reticular nuclei lost 60%. These findings point to the disorganization of most thalamic circuits as a condition necessary for the sleep-wake rhythm being affected.

  18. An Unusual Case of Extensive Lattice Degeneration and Retinal Detachment

    PubMed Central

    Sarma, Saurabh Kumar; Basaiawmoit, Jennifer V.

    2016-01-01

    Lattice degeneration of the retina is not infrequently encountered on a dilated retinal examination and many of them do not need any intervention. We report a case of atypical lattice degeneration variant with peripheral retinal detachment. An asymptomatic 35-year-old lady with minimal refractive error was found to have extensive lattice degeneration, peripheral retinal detachment and fibrotic changes peripherally with elevation of retinal vessels on dilated retinal examination. There were also areas of white without pressure, chorioretinal scarring and retinal breaks. All the changes were limited to beyond the equator but were found to span 360 degrees. She was treated with barrage laser all around to prevent extension of the retinal detachment posteriorly. She remained stable till her latest follow-up two years after the barrage laser. This case is reported for its rarity with a discussion of the probable differential diagnoses. To the best of our knowledge, this is the first report of such findings in lattice degeneration. PMID:27630875

  19. Nutritional modulation of age-related macular degeneration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly worldwide. It affects 30-50 million individuals and clinical hallmarks of AMD are observed in at least one third of persons over the age of 75 in industrialized countries (Gehrs et al., 2006). Costs associated wi...

  20. Late degeneration of transcatheter aortic valves: pathogenesis and management.

    PubMed

    Barbanti, Marco; Tamburino, Corrado

    2016-09-18

    There is a growing body of evidence demonstrating the durability of current transcatheter aortic valve implantation (TAVI) devices up to 5 years. However, it is well known that transcatheter aortic valves can degenerate in a manner similar to surgical bioprostheses. In this review we briefly discuss the modes of failure of trans-catheter aortic valves and their potential management. PMID:27640028

  1. 9 CFR 311.35 - Muscular inflammation, degeneration, or infiltration.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... PARTS § 311.35 Muscular inflammation, degeneration, or infiltration. (a) If muscular lesions are found... carcass shall be condemned. (b) If muscular lesions are found to be distributed in such a manner or to be... carcasses, edible organs, and other parts of carcasses showing such muscular lesions. If the lesions...

  2. Biological treatment strategies for disc degeneration: potentials and shortcomings

    PubMed Central

    Nerlich, Andreas G.; Boos, Norbert

    2006-01-01

    Recent advances in molecular biology, cell biology and material sciences have opened a new emerging field of techniques for the treatment of musculoskeletal disorders. These new treatment modalities aim for biological repair of the affected tissues by introducing cell-based tissue replacements, genetic modifications of resident cells or a combination thereof. So far, these techniques have been successfully applied to various tissues such as bone and cartilage. However, application of these treatment modalities to cure intervertebral disc degeneration is in its very early stages and mostly limited to experimental studies in vitro or in animal studies. We will discuss the potential and possible shortcomings of current approaches to biologically cure disc degeneration by gene therapy or tissue engineering. Despite the increasing number of studies examining the therapeutic potential of biological treatment strategies, a practicable solution to routinely cure disc degeneration might not be available in the near future. However, knowledge gained from these attempts might be applied in a foreseeable future to cure the low back pain that often accompanies disc degeneration and therefore be beneficial for the patient. PMID:16983559

  3. Oocyte Degeneration Associated with Follicle Cells in Female Mactra chinensis (Bivalvia: Mactridae)

    PubMed Central

    Kim, Sung Han; Chung, Ee-Yung; Lee, Ki-Young

    2014-01-01

    Ultrastructural studies of oocyte degeneration in the oocyte, and the functions of follicle cells during oocyte degeneration are described to clarify the reproductive mechanism on oocyte degeneration of Mactra chinensis using cytological methods. Commonly, the follicle cells are attached to the oocyte. Follicle cells play an important role in oocyte degeneration. In particular, the functions of follicle cells during oocyte degeneration are associated with phagocytosis and the intracellular digestion of products. In this study, morphologically similar degenerated phagosomes (various lysosomes), which were observed in the degenerated oocytes, appeared in the follicle cells. After the spawning of the oocytes, the follicle cells were involved in oocyte degeneration through phagocytosis by phagolysosomes. Therefore, it can be assumed that follicle cells reabsorb phagosomes from degenerated oocytes. In this study, the presence of lipid granules, which occurred from degenerating yolk granules, gradually increased in degenerating oocytes. The function of follicle cells can accumulate reserves of lipid granules and glycogen in the cytoplasm, which can be employed by the vitellogenic oocyte. Based on observations of follicle cells attached to degenerating oocytes after spawning, the follicle cells of this species are involved in the lysosomal induction of oocyte degeneration for the reabsorption of phagosomes (phagolysosomes) in the cytoplasm for nutrient storage, as seen in other bivalves. PMID:25949203

  4. Protective effects of aqueous garlic extract in reducing water avoidance stress-induced degeneration of the stomach, ileum, and liver: morphological and biochemical study.

    PubMed

    Zeybek, Ali; Ercan, Feriha; Cetinel, Sule; Cikler, Esra; Saglam, Beyhan; Sener, Göksel

    2007-11-01

    We investigated the effect of aqueous garlic extract (AGE) on water avoidance stress (WAS)-induced degeneration of the gastric and ileal mucosa and liver parenchyma. Wistar albino rats were exposed to WAS (WAS group) for 5 days. After exposure of the animals to WAS, a 1 ml/kg aqueous garlic extract (AGE) was injected i.p. (WAS+AGE group). The stomach, ileum, and liver samples were investigated under light microscope for general morphology. Topography of gastric and ileal mucosa was investigated by scanning electron microscopy, and hepatocyte ultastructure by transmission electron micsroscopy. Malondialdehyde (MDA) and glutathione (GSH) levels of all tissues were also determined. In the WAS group, the epithelium of the stomach showed ulceration in some areas, dilatations of the gastric glands, and degeneration of gastric glandular cells. Severe vascular congestion and degeneration of ileal epithelium were observed. Prominent vascular congestion and dilated sinusoids, activated Kupffer cells with prominent morphology, dilated granular endoplasmic reticulum membranes, and focal picnotic nuclei were observed in liver parenchyma. AGE treatment reduced the degeneration of the gastric and ileal mucosa and liver parenchyma. Increased MDA levels and decreased GSH levels in the WAS group were reversed to control values after AGE treatment. Based on these results, AGE treatment significantly prevented WAS-induced degeneration in both morphology and biochemistry of gastrointestinal mucosa and liver parenchyma due to its potent free radical scavenging and antioxidant properties.

  5. Viruses Associated with Ovarian Degeneration in Apis mellifera L. Queens

    PubMed Central

    Gauthier, Laurent; Ravallec, Marc; Tournaire, Magali; Cousserans, François; Bergoin, Max; Dainat, Benjamin; de Miranda, Joachim R.

    2011-01-01

    Queen fecundity is a critical issue for the health of honeybee (Apis mellifera L.) colonies, as she is the only reproductive female in the colony and responsible for the constant renewal of the worker bee population. Any factor affecting the queen's fecundity will stagnate colony development, increasing its susceptibility to opportunistic pathogens. We discovered a pathology affecting the ovaries, characterized by a yellow discoloration concentrated in the apex of the ovaries resulting from degenerative lesions in the follicles. In extreme cases, marked by intense discoloration, the majority of the ovarioles were affected and these cases were universally associated with egg-laying deficiencies in the queens. Microscopic examination of the degenerated follicles showed extensive paracrystal lattices of 30 nm icosahedral viral particles. A cDNA library from degenerated ovaries contained a high frequency of deformed wing virus (DWV) and Varroa destructor virus 1 (VDV-1) sequences, two common and closely related honeybee Iflaviruses. These could also be identified by in situ hybridization in various parts of the ovary. A large-scale survey for 10 distinct honeybee viruses showed that DWV and VDV-1 were by far the most prevalent honeybee viruses in queen populations, with distinctly higher prevalence in mated queens (100% and 67%, respectively for DWV and VDV-1) than in virgin queens (37% and 0%, respectively). Since very high viral titres could be recorded in the ovaries and abdomens of both functional and deficient queens, no significant correlation could be made between viral titre and ovarian degeneration or egg-laying deficiency among the wider population of queens. Although our data suggest that DWV and VDV-1 have a role in extreme cases of ovarian degeneration, infection of the ovaries by these viruses does not necessarily result in ovarian degeneration, even at high titres, and additional factors are likely to be involved in this pathology. PMID:21283547

  6. Viruses associated with ovarian degeneration in Apis mellifera L. queens.

    PubMed

    Gauthier, Laurent; Ravallec, Marc; Tournaire, Magali; Cousserans, François; Bergoin, Max; Dainat, Benjamin; de Miranda, Joachim R

    2011-01-25

    Queen fecundity is a critical issue for the health of honeybee (Apis mellifera L.) colonies, as she is the only reproductive female in the colony and responsible for the constant renewal of the worker bee population. Any factor affecting the queen's fecundity will stagnate colony development, increasing its susceptibility to opportunistic pathogens. We discovered a pathology affecting the ovaries, characterized by a yellow discoloration concentrated in the apex of the ovaries resulting from degenerative lesions in the follicles. In extreme cases, marked by intense discoloration, the majority of the ovarioles were affected and these cases were universally associated with egg-laying deficiencies in the queens. Microscopic examination of the degenerated follicles showed extensive paracrystal lattices of 30 nm icosahedral viral particles. A cDNA library from degenerated ovaries contained a high frequency of deformed wing virus (DWV) and Varroa destructor virus 1 (VDV-1) sequences, two common and closely related honeybee Iflaviruses. These could also be identified by in situ hybridization in various parts of the ovary. A large-scale survey for 10 distinct honeybee viruses showed that DWV and VDV-1 were by far the most prevalent honeybee viruses in queen populations, with distinctly higher prevalence in mated queens (100% and 67%, respectively for DWV and VDV-1) than in virgin queens (37% and 0%, respectively). Since very high viral titres could be recorded in the ovaries and abdomens of both functional and deficient queens, no significant correlation could be made between viral titre and ovarian degeneration or egg-laying deficiency among the wider population of queens. Although our data suggest that DWV and VDV-1 have a role in extreme cases of ovarian degeneration, infection of the ovaries by these viruses does not necessarily result in ovarian degeneration, even at high titres, and additional factors are likely to be involved in this pathology.

  7. Computer image analysis of toxic fatty degeneration in rat liver.

    PubMed

    Stetkiewicz, J; Zieliński, K; Stetkiewicz, I; Koktysz, R

    1989-01-01

    Fatty degeneration of the liver is one of the most frequently observed pathological changes in the experimental estimation of the toxicity of chemical compounds. The intensity of this kind of damage is most often detected by means of a generally accepted scale of points, whereas the classification is performed according to the subjective "feeling" of the pathologist. In modern pathological diagnostics, computer analysis of images is used to perform an objective estimation of the degree of damage to various organs. In order to check the usefulness of this kind of method, comparative biochemical and morphometrical studies were undertaken in trichloroethylene (TRI)-induced fatty degeneration of the liver. TRI was administered to rats intragastrically, in single doses: 1/2; 1/3; 1/4; 1/6 and 1/18 DL50. 24 hours after the administration, the animals were sacrificed. The content of triglycerides in the liver was determined according to Folch et al. (1956). Simple lipids in the histochemical samples were detected by means of staining with a lipotropic, Fat Red 7B. The area of fatty degeneration was estimated in the microscopic samples by the use of an automatic image analyser IBAS 2000 (Kontron). The morphometrical data concerning the area of fatty degeneration in the liver amplified a high degree of correlation with the content of triglycerides (r = 0.89) and the dose of TRI (r = 0.96). The degree of correlation between the biochemical data and the dose of TRI was 0.88. The morphometrical studies performed have proved to be of great use in estimating the degree of fatty degeneration in the liver. This method enables precise, quantitative measuring of this sort of liver damage in the material prepared for routine histopathological analysis. It requires, however, the application of a specialized device for quantitative image analysis.

  8. Temporal profiles of neuronal degeneration, glial proliferation, and cell death in hNFL(+/+) and NFL(-/-) mice.

    PubMed

    McLean, Jesse R; Sanelli, Teresa R; Leystra-Lantz, Cheryl; He, Bei Ping; Strong, Michael J

    2005-10-01

    Neurofilament (NF) aggregate formation within motor neurons is a pathological hallmark of both the sporadic and familial forms of amyotrophic lateral sclerosis (ALS). The relationship between aggregate formation and both microglial and astrocytic proliferation, as well as additional neuropathological features of ALS, is unknown. To examine this, we have used transgenic mice that develop NF aggregates, through either a lack of the low-molecular-weight NF subunit [NFL (-/-)] or the overexpression of human NFL [hNFL (+/+)]. Transgenic and wild-type C57bl/6 mice were examined from 1 month to 18 months of age, and the temporal pattern of motor neuron degeneration, microglial and astrocytic proliferation, and heat shock protein-70 (HSP-70) expression characterized. We observed three overlapping phases in both transgenic mice, including transient aggregate formation, reactive microgliosis, and progressive motor neuron loss. However, only NFL (-/-) mice demonstrated significant astrogliosis and HSP-70 upregulation in both motor neurons and astrocytes. These in vivo models suggest that the development of NF aggregates in motor neurons leads to motor neuron death, but that the interaction between the degenerating motor neurons and the adjacent non-neuronal cells may differ significantly depending on the etiology of the NF aggregate itself.

  9. Perfluoroalkyl substances in Daling River adjacent to fluorine industrial parks: implication from industrial emission.

    PubMed

    Meng, Jing; Wang, Tieyu; Wang, Pei; Zhu, Zhaoyun; Li, Qifeng; Lu, Yonglong

    2015-01-01

    The pollution level and source of perfluoroalkyl substances (PFASs) in mainstream and tributary of Daling River in northeast China were investigated in present study. Concentrations of PFASs in surface water and sediment ranged from 4.6 to 3,410 ng/L and from 0.08 to 2.6 ng/g dry weight, respectively. The lowest levels of PFASs were found in vicinity of a drinking water source located in upstream of Daling River. Xihe tributary, which is adjacent to two local fluorine industrial parks, contained the highest level of PFASs. Short-chain PFASs, including perfluorobutanoic acid and perfluorobutane sulfonate, were of higher levels due to their emerging as alternative products for perfluorooctane sulfonate. High level of perfluorooctanoic acid was also found in Daling River. Based on these results, it can be concluded that the relatively severe pollutions of Xihe tributary were caused by long-term development of the two local fluorine industry parks.

  10. Prospective, Randomized Comparison of One-level Mobi-C Cervical Total Disc Replacement vs. Anterior Cervical Discectomy and Fusion: Results at 5-year Follow-up

    PubMed Central

    Zigler, Jack E.; Jackson, Robert; Nunley, Pierce D.; Bae, Hyun W.; Kim, Kee D.; Ohnmeiss, Donna D.

    2016-01-01

    Introduction There is increasing interest in the role of cervical total disc replacement (TDR) as an alternative to anterior cervical discectomy and fusion (ACDF). Multiple prospective randomized studies with minimum 2 year follow-up have shown TDR to be at least as safe and effective as ACDF in treating symptomatic degenerative disc disease at a single level. The purpose of this study was to compare outcomes of cervical TDR using the Mobi-C® with ACDF at 5-year follow-up. Methods This prospective, randomized, controlled trial was conducted as a Food and Drug Administration regulated Investigational Device Exemption trial across 23 centers with 245 patients randomized (2:1) to receive TDR with Mobi-C® Cervical Disc Prosthesis or ACDF with anterior plate and allograft. Outcome assessments included a composite overall success score, Neck Disability Index (NDI), visual analog scales (VAS) assessing neck and arm pain, Short Form-12 (SF-12) health survey, patient satisfaction, major complications, subsequent surgery, segmental range of motion, and adjacent segment degeneration. Results The 60-month follow-up rate was 85.5% for the TDR group and 78.9% for the ACDF group. The composite overall success was 61.9% with TDR vs. 52.2% with ACDF, demonstrating statistical non-inferiority. Improvements in NDI, VAS neck and arm pain, and SF-12 scores were similar between groups and were maintained from earlier follow-up through 60 months. There was no significant difference between TDR and ACDF in adverse events or major complications. Range of motion was maintained with TDR through 60 months. Device-related subsequent surgeries (TDR: 3.0%, ACDF: 11.1%, p<0.02) and adjacent segment degeneration at the superior level (TDR: 37.1%, ACDF: 54.7%, p<0.03) were significantly lower for TDR patients. Conclusions Five-year results demonstrate the safety and efficacy of TDR with the Mobi-C as a viable alternative to ACDF with the potential advantage of lower rates of reoperation and

  11. Bacterial community composition in Brazilian Anthrosols and adjacent soils characterized using culturing and molecular identification.

    PubMed

    O'Neill, B; Grossman, J; Tsai, M T; Gomes, J E; Lehmann, J; Peterson, J; Neves, E; Thies, J E

    2009-07-01

    Microbial community composition was examined in two soil types, Anthrosols and adjacent soils, sampled from three locations in the Brazilian Amazon. The Anthrosols, also known as Amazonian dark earths, are highly fertile soils that are a legacy of pre-Columbian settlement. Both Anthrosols and adjacent soils are derived from the same parent material and subject to the same environmental conditions, including rainfall and temperature; however, the Anthrosols contain high levels of charcoal-like black carbon from which they derive their dark color. The Anthrosols typically have higher cation exchange capacity, higher pH, and higher phosphorus and calcium contents. We used culture media prepared from soil extracts to isolate bacteria unique to the two soil types and then sequenced their 16S rRNA genes to determine their phylogenetic placement. Higher numbers of culturable bacteria, by over two orders of magnitude at the deepest sampling depths, were counted in the Anthrosols. Sequences of bacteria isolated on soil extract media yielded five possible new bacterial families. Also, a higher number of families in the bacteria were represented by isolates from the deeper soil depths in the Anthrosols. Higher bacterial populations and a greater diversity of isolates were found in all of the Anthrosols, to a depth of up to 1 m, compared to adjacent soils located within 50-500 m of their associated Anthrosols. Compared to standard culture media, soil extract media revealed diverse soil microbial populations adapted to the unique biochemistry and physiological ecology of these Anthrosols. PMID:19381712

  12. Differentially Expressed miRNAs in Tumor, Adjacent, and Normal Tissues of Lung Adenocarcinoma

    PubMed Central

    Tian, Fei; Li, Rui; Chen, Zhenzhu; Shen, Yanting; Lu, Jiafeng; Xie, Xueying; Ge, Qinyu

    2016-01-01

    Lung cancer is the leading cause of cancer deaths. Non-small-cell lung cancer (NSCLC) is the major type of lung cancer. The aim of this study was to characterize the expression profiles of miRNAs in adenocarcinoma (AC), one major subtype of NSCLC. In this study, the miRNAs were detected in normal, adjacent, and tumor tissues by next-generation sequencing. Then the expression levels of differential miRNAs were quantified by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). In the results, 259, 401, and 389 miRNAs were detected in tumor, adjacent, and normal tissues of pooled AC samples, respectively. In addition, for the first time we have found that miR-21-5p and miR-196a-5p were gradually upregulated from normal to adjacent to tumor tissues; miR-218-5p was gradually downregulated with 2-fold or greater change in AC tissues. These 3 miRNAs were validated by qRT-PCR. Lastly, we predicted target genes of these 3 miRNAs and enriched the potential functions and regulatory pathways. The aberrant miR-21-5p, miR-196a-5p, and miR-218-5p may become biomarkers for diagnosis and prognosis of lung adenocarcinoma. This research may be useful for lung adenocarcinoma diagnosis and the study of pathology in lung cancer. PMID:27247934

  13. Unmixing multiple adjacent fluorescent targets with multispectral excited fluorescence molecular tomography.

    PubMed

    Zhou, Yuan; Guang, Huizhi; Pu, Huangsheng; Zhang, Jiulou; Luo, Jianwen

    2016-06-20

    Fluorescence molecular tomography (FMT) can visualize biological activities at cellular and molecular levels in vivo, and has been extensively used in drug delivery and tumor detection research of small animals. The ill-posedness of the FMT inverse problem makes it difficult to reconstruct and unmix multiple adjacent fluorescent targets that have different functional features but are labeled with the same fluorochrome. A method based on independent component analysis for multispectral excited FMT was proposed in our previous study. It showed that double fluorescent targets with certain edge-to-edge distance (EED) could be unmixed by the method. In this study, the situation is promoted to unmix multiple adjacent fluorescent targets (i.e., more than two fluorescent targets and EED=0). Phantom experiments on the resolving ability of the proposed algorithm demonstrate that the algorithm performs well in unmixing multiple adjacent fluorescent targets in both lateral and axial directions. And also, we recovered the locational information of each independent fluorescent target and described the variable trends of the corresponding fluorescent targets under the excitation spectrum. This method is capable of unmixing multiple fluorescent targets with small EED but labeled with the same fluorochrome, and may be used in imaging of nonspecific probe targeting and metabolism of drugs. PMID:27409108

  14. Matrix intensification alters avian functional group composition in adjacent rainforest fragments.

    PubMed

    Deikumah, Justus P; McAlpine, Clive A; Maron, Martine

    2013-01-01

    Conversion of farmland land-use matrices to surface mining is an increasing threat to the habitat quality of forest remnants and their constituent biota, with consequences for ecosystem functionality. We evaluated the effects of matrix type on bird community composition and the abundance and evenness within avian functional groups in south-west Ghana. We hypothesized that surface mining near remnants may result in a shift in functional composition of avifaunal communities, potentially disrupting ecological processes within tropical forest ecosystems. Matrix intensification and proximity to the remnant edge strongly influenced the abundance of members of several functional guilds. Obligate frugivores, strict terrestrial insectivores, lower and upper strata birds, and insect gleaners were most negatively affected by adjacent mining matrices, suggesting certain ecosystem processes such as seed dispersal may be disrupted by landscape change in this region. Evenness of these functional guilds was also lower in remnants adjacent to surface mining, regardless of the distance from remnant edge, with the exception of strict terrestrial insectivores. These shifts suggest matrix intensification can influence avian functional group composition and related ecosystem-level processes in adjacent forest remnants. The management of matrix habitat quality near and within mine concessions is important for improving efforts to preserveavian biodiversity in landscapes undergoing intensification such as through increased surface mining. PMID:24058634

  15. Apolipoprotein E promotes subretinal mononuclear phagocyte survival and chronic inflammation in age-related macular degeneration.

    PubMed

    Levy, Olivier; Calippe, Bertrand; Lavalette, Sophie; Hu, Shulong J; Raoul, William; Dominguez, Elisa; Housset, Michael; Paques, Michel; Sahel, José-Alain; Bemelmans, Alexis-Pierre; Combadiere, Christophe; Guillonneau, Xavier; Sennlaub, Florian

    2015-02-01

    Physiologically, the retinal pigment epithelium (RPE) expresses immunosuppressive signals such as FAS ligand (FASL), which prevents the accumulation of leukocytes in the subretinal space. Age-related macular degeneration (AMD) is associated with a breakdown of the subretinal immunosuppressive environment and chronic accumulation of mononuclear phagocytes (MPs). We show that subretinal MPs in AMD patients accumulate on the RPE and express high levels of APOE. MPs of Cx3cr1(-/-) mice that develop MP accumulation on the RPE, photoreceptor degeneration, and increased choroidal neovascularization similarly express high levels of APOE. ApoE deletion in Cx3cr1(-/-) mice prevents pathogenic age- and stress-induced subretinal MP accumulation. We demonstrate that increased APOE levels induce IL-6 in MPs via the activation of the TLR2-CD14-dependent innate immunity receptor cluster. IL-6 in turn represses RPE FasL expression and prolongs subretinal MP survival. This mechanism may account, in part, for the MP accumulation observed in Cx3cr1(-/-) mice. Our results underline the inflammatory role of APOE in sterile inflammation in the immunosuppressive subretinal space. They provide rationale for the implication of IL-6 in AMD and open avenues toward therapies inhibiting pathogenic chronic inflammation in late AMD.

  16. Apolipoprotein E promotes subretinal mononuclear phagocyte survival and chronic inflammation in age-related macular degeneration

    PubMed Central

    Levy, Olivier; Calippe, Bertrand; Lavalette, Sophie; Hu, Shulong J; Raoul, William; Dominguez, Elisa; Housset, Michael; Paques, Michel; Sahel, José-Alain; Bemelmans, Alexis-Pierre; Combadiere, Christophe; Guillonneau, Xavier; Sennlaub, Florian

    2015-01-01

    Physiologically, the retinal pigment epithelium (RPE) expresses immunosuppressive signals such as FAS ligand (FASL), which prevents the accumulation of leukocytes in the subretinal space. Age-related macular degeneration (AMD) is associated with a breakdown of the subretinal immunosuppressive environment and chronic accumulation of mononuclear phagocytes (MPs). We show that subretinal MPs in AMD patients accumulate on the RPE and express high levels of APOE. MPs of Cx3cr1−/− mice that develop MP accumulation on the RPE, photoreceptor degeneration, and increased choroidal neovascularization similarly express high levels of APOE. ApoE deletion in Cx3cr1−/− mice prevents pathogenic age- and stress-induced subretinal MP accumulation. We demonstrate that increased APOE levels induce IL-6 in MPs via the activation of the TLR2-CD14-dependent innate immunity receptor cluster. IL-6 in turn represses RPE FasL expression and prolongs subretinal MP survival. This mechanism may account, in part, for the MP accumulation observed in Cx3cr1−/− mice. Our results underline the inflammatory role of APOE in sterile inflammation in the immunosuppressive subretinal space. They provide rationale for the implication of IL-6 in AMD and open avenues toward therapies inhibiting pathogenic chronic inflammation in late AMD. PMID:25604058

  17. New adjacent Bis-tetrahydrofuran Annonaceous acetogenins from Annona muricata.

    PubMed

    Chang, Fang-Rong; Liaw, Chih-Chuang; Lin, Chih-Yuan; Chou, Chi-Jung; Chiu, Hui-Fen; Wu, Yang-Chang

    2003-03-01

    Bioactivity-guided fractionation led to the isolation of two new Annonaceous acetogenins, annocatacin A ( 1). and annocatacin B ( 2). from the seeds and the leaves, respectively, of Annona muricata. Compounds 1 and 2 are the first examples where the adjacent bis-tetrahydrofuran ring system is located at C-15. The new structures were elucidated and characterized by spectral and chemical methods. Both Annonaceous acetogenins 1 and 2 showed significant in vitro cytotoxicity toward the human hepatoma cell lines, Hep G2 and 2,2,15, and were compared with the known adjacent bis-tetrahydrofuran acetogenins, neoannonin ( 3). desacetyluvaricin ( 4). bullatacin ( 5). asimicin ( 6). annoglaucin ( 7). squamocin ( 8). and rollimusin ( 9).

  18. Protein misfolding and the pathogenesis of ABCA4-associated retinal degenerations

    PubMed Central

    Zhang, Ning; Tsybovsky, Yaroslav; Kolesnikov, Alexander V.; Rozanowska, Malgorzata; Swider, Malgorzata; Schwartz, Sharon B.; Stone, Edwin M.; Palczewska, Grazyna; Maeda, Akiko; Kefalov, Vladimir J.; Jacobson, Samuel G.; Cideciyan, Artur V.; Palczewski, Krzysztof

    2015-01-01

    Mutations in the ABCA4 gene are a common cause of autosomal recessive retinal degeneration. All mouse models to date are based on knockouts of Abca4, even though the disease is often caused by missense mutations such as the complex allele L541P;A1038V (PV). We now show that the PV mutation causes severe human disease whereas the V mutation alone causes mild disease. Mutant ABCA4 proteins expressed heterologously in mammalian cells retained normal cellular localization. However, basal and all-trans-retinal-stimulated ATPase activities were reduced substantially for P and PV but only mildly for V. Electron microscopy revealed marked structural changes and misfolding for the P and PV mutants but few changes for the V mutant, consistent with the disease severity difference in patients. We generated Abca4PV/PV knock-in mice homozygous for the complex PV allele to investigate the effects of this misfolding mutation in vivo. Mutant ABCA4 RNA levels approximated WT ABCA4 RNA levels but, surprisingly, only trace amounts of mutant ABCA4 protein were noted in the retina. RNA sequencing of WT, Abca4−/− and Abca4PV/PV mice revealed mild gene expression alterations in the retina and RPE. Similar to Abca4−/− mice, Abca4PV/PV mice showed substantial A2E and lipofuscin accumulation in their RPE cells but no retinal degeneration up to 12 months of age. Thus, rapid degradation of this large misfolded mutant protein in mouse retina caused little detectable photoreceptor degeneration. These findings suggest likely differences in the unfolded protein response between murine and human photoreceptors and support development of therapies directed at increasing this capability in patients. PMID:25712131

  19. Involvement of endoplasmic reticulum stress in all-trans-retinal-induced retinal pigment epithelium degeneration.

    PubMed

    Li, Jie; Cai, Xianhui; Xia, Qingqing; Yao, Ke; Chen, Jingmeng; Zhang, Yanli; Naranmandura, Hua; Liu, Xin; Wu, Yalin

    2015-01-01

    Excess accumulation of endogenous all-trans-retinal (atRAL) contributes to degeneration of the retinal pigment epithelium (RPE) and photoreceptor cells, and plays a role in the etiologies of age-related macular degeneration (AMD) and Stargardt's disease. In this study, we reveal that human RPE cells tolerate exposure of up to 5 µM atRAL without deleterious effects, but higher concentrations are detrimental and induce cell apoptosis. atRAL treatment significantly increased production of intracellular reactive oxygen species (ROS) and up-regulated mRNA expression of Nrf2, HO-1, and γ-GCSh within RPE cells, thereby causing oxidative stress. ROS localized to mitochondria and endoplasmic reticulum (ER). ER-resident molecular chaperone BiP, a marker of ER stress, was up-regulated at the translational level, and meanwhile, the PERK-eIF2α-ATF4 signaling pathway was activated. Expression levels of ATF4, CHOP, and GADD34 in RPE cells increased in a concentration-dependent manner after incubation with atRAL. Salubrinal, a selective inhibitor of ER stress, alleviated atRAL-induced cell death. The antioxidant N-acetylcysteine (NAC) effectively blocked RPE cell loss and ER stress activation, suggesting that atRAL-induced ROS generation is responsible for RPE degeneration and is an early trigger of ER stress. Furthermore, the mitochondrial transmembrane potential was lost after atRAL exposure, and was followed by caspase-3 activation and poly (ADP-ribose) polymerase cleavage. The results demonstrate that atRAL-driven ROS overproduction-induced ER stress is involved in cellular mitochondrial dysfunction and apoptosis of RPE cells. PMID:25331497

  20. THE SHOENBERG EFFECT IN A RELATIVISTIC DEGENERATE ELECTRON GAS AND OBSERVATIONAL EVIDENCE IN MAGNETARS

    SciTech Connect

    Wang Zhaojun; Lue Guoliang; Zhu Chunhua; Huo Wensheng E-mail: guolianglv@gmail.com

    2013-08-20

    The electron gas inside a neutron star is highly degenerate and relativistic. Due to electron-electron magnetic interactions, the differential susceptibility can equal or exceed one, which causes the magnetic system of the neutron star to become metastable or unstable. The Fermi liquid of nucleons under the crust can be in a metastable state, while the crust is unstable to the formation of layers of alternating magnetization. The change of the magnetic stress acting on adjacent domains can result in a series of shifts or fractures in the crust. The release of magnetic free energy and elastic energy in the crust can cause the bursts observed in magnetars. Simultaneously, a series of shifts or fractures in the deep crust that is close to the Fermi liquid of nucleons can trigger a phase transition of the Fermi liquid of nucleons from a metastable state to a stable state. The magnetic free energy released in the Fermi liquid of nucleons corresponds to the giant flares observed in some magnetars.