Hierarchical Bin Buffering: Online Local Moments for Dynamic External Memory Arrays

Local moments are used for local regression, to compute statistical measures such as sums, averages, and standard deviations, and to approximate probability distributions. We consider the case where the data source is a very large I/O array of size n and we want to compute the first N local moments, for some constant N. Without precomputation, this requires O(n) time. We develop a sequence of algorithms of increasing sophistication that use precomputation and additional buffer space to speed up queries. The simpler algorithms partition the I/O array into consecutive ranges called bins, and they are applicable not only to local-moment queries, but also to algebraic queries (MAX, AVERAGE, SUM, etc.). With N buffers of size sqrt{n}, time complexity drops to O(sqrt n). A more sophisticated approach uses hierarchical buffering and has a logarithmic time complexity (O(b log_b n)), when using N hierarchical buffers of size n/b. Using Overlapped Bin Buffering, we show that only a single buffer is needed, as with wavelet-based algorithms, but using much less storage. Applications exist in multidimensional and statistical databases over massive data sets, interactive image processing, and visualization

Un caso de síndrome de mano ajena fronto-calloso

Setenes Jornades de Foment de la Investigació de la FCHS (Any 2001-2002)Diferentes estudios teóricos (Feinberg, y cols., 1992; Baynes y cols. 1997; Doody y Jankovic 1992) han mostrado que el síndrome de la mano ajena (Brion y Jedynak 1972) puede tener dos manifestaciones que son: mano ajena con afectación callosa y mano ajena de afectación fronto-callosa. Este estudio presenta el caso de una mujer de 63 años relacionado con este último síndrome. Ingresada por torpeza en miembros inferiores, alteración del habla, hemiparesia derecha y cefalea. Las técnicas de neuroimagen mostraron signos indirectos de infarto en la arteria cerebral anterior izquierda que afectaban al área motora suplementaria y el cuerpo calloso. Las pruebas neuropsicológicas evaluaron funciones de atención, lenguaje, memoria, gnosias, praxias y funciones ejecutivas. Los resultados de las pruebas indicaron déficits en distintas funciones cognitivas superiores entre las que destacaba el síndrome de utilización compulsiva de objetos. Para profundizar en el análisis de este síndrome se planteó un estudio Resonancia Magnética Funcional del que se desprende que el área premotora contralateral es la responsable de los movimientos de la mano ajena

Treatment of Angular Deformity and Limb Length Discrepancy With a Retrograde Femur Magnetic Intramedullary Nail: A Fixator-assisted, Blocking Screw Technique

Background: Fixator-assisted nailing techniques that incorporate magnetic internal lengthening nails (MILNs) permit acute deformity correction and then gradual limb lengthening without needing postoperative external fixators. Purposes: We sought to investigate the safety and accuracy of a fixator-assisted, blocking screw technique using retrograde MILNs for the correction of LLD and limb malalignment. Methods: Forty-one patients (13 patients with genu varum and 28 patients with genu valgum) with LLD treated with fixator-assisted, blocking screw retrograde MILN reconstruction were included. Preoperative LLD, mechanical axis deviation, and joint orientation angles were compared with values at the end of treatment, and bone healing indices were calculated. Perioperative complications were tracked. Results: Preoperatively, the mean mechanical lateral distal femoral angle of the varus cohort was 98 ± 12°, whereas the mean lateral distal femoral angle of the valgus cohort was 82±4°. Both cohorts had an average 3-cm LLD. 99% of the planned limb lengthening was achieved. Final LDFAs were 91 ± 6° and 89 ± 4° in the varus and valgus cohorts, respectively, and the limb mechanical axis angles were normalized. 10 patients underwent a total of 21 returns to the operating room. Most commonly, this involved percutaneous injection of bone marrow aspirate concentrate to bone regenerate exhibiting delayed union (6 patients). Conclusions: The use of a retrograde MILN with a fixator-assisted, blocking screw technique is an effective means of acute deformity correction and gradual limb lengthening through minimal incisions. The accuracy of deformity correction relies on intraoperative execution of the appropriate nail start site, osteotomy location, and placement of blocking screws

Aggregate risk of cardiovascular disease among adolescents perinatally infected with the human immunodeficiency virus

BACKGROUND: Perinatally HIV-infected adolescents may be susceptible to aggregate atherosclerotic cardiovascular disease risk, as measured by the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) coronary arteries and abdominal aorta risk scores, as a result of prolonged exposure to HIV and antiretroviral therapy. METHODS AND RESULTS: Coronary arteries and abdominal aorta PDAY scores were calculated for 165 perinatally HIV-infected adolescents, using a weighted combination of modifiable risk factors: dyslipidemia, cigarette smoking, hypertension, obesity, and hyperglycemia. Demographic and HIV-specific predictors of scores ≥1 were identified, and trends in scores over time were assessed. Forty-eight percent and 24% of the perinatally HIV-infected adolescents had coronary arteries and abdominal aorta scores ≥1, representing increased cardiovascular disease risk factor burden. Significant predictors of coronary arteries scores ≥1 included male sex, history of an AIDS-defining condition, longer duration of use of a ritonavir-boosted protease inhibitor, and no prior use of tenofovir. Significant predictors of abdominal aorta scores ≥1 included suppressed viral load, history of an AIDS-defining condition, and longer duration of boosted protease inhibitor use. No significant changes in coronary arteries and abdominal aorta risk scores were observed over the 4-year study period. CONCLUSIONS: A substantial proportion of perinatally HIV-infected youth have high PDAY scores, reflecting increased aggregate atherosclerotic cardiovascular disease risk factor burden. High scores were predicted by HIV disease severity and boosted protease inhibitor use. PDAY scores may be useful in identifying high-risk youth who may benefit from early lifestyle or clinical interventions

The effect of mesenchymal stem cell transplantation on the recovery of bladder and hindlimb function after spinal cord contusion in rats

<p>Abstract</p> <p>Background</p> <p>Mesenchymal stem cells are widely used for transplantation into the injured spinal cord in vivo model and for safety, many human clinical trials are continuing to promote improvements of motor and sensory functions after spinal cord injury. Yet the exact mechanism for these improvements remains undefined. Neurogenic bladder following spinal cord injury is the main problem decreasing the quality of life for patients with spinal cord injury, but there are no clear data using stem cell transplantation for the improvement of neurogenic bladder for in vivo studies and the clinical setting.</p> <p>The purpose of this study was to delineate the effect of human mesenchymal stem cell (hMSCs) transplantation on the restoration of neurogenic bladder and impaired hindlimb function after spinal cord contusion of rats and the relationship between neurotrophic factors such as brain derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) and bladder and hindlimb functions.</p> <p>Results</p> <p>Modified moderate contusion injury were performed on the thoracic spinal cord of Sprague-Dawley rats using MASCIS impactor and hMSCs, human fibroblasts or phosphate-buffered saline were transplanted into injured spinal cord 9 days after injury for hMSC and two control groups respectively. Ladder test showed more rapid restoration of hindlimb function in hMSC group than in control group, but Basso, Beattie, and Bresnahan score and coupling score were not different significantly among hMSC and two control groups. Neurogenic bladder was not improved in either group. ED1 positive macrophages were significantly reduced in hMSC group than in two control groups, but ELISA and RT-PCR studies revealed BDNF and NT-3 levels in spinal cord and bladder were not different among hMSC and two control groups regardless the experimental duration.</p> <p>Conclusion</p> <p>hMSC transplantation was effective in reducing inflammatory reaction after spinal cord contusion of rats but not sufficient to recover locomotor and bladder dysfunction. BDNF and NT-3 levels in the spinal cord and bladder were not increased 28 and 56 days after hMSC transplantation.</p

Cellular therapies for treating pain associated with spinal cord injury

Spinal cord injury leads to immense disability and loss of quality of life in human with no satisfactory clinical cure. Cell-based or cell-related therapies have emerged as promising therapeutic potentials both in regeneration of spinal cord and mitigation of neuropathic pain due to spinal cord injury. This article reviews the various options and their latest developments with an update on their therapeutic potentials and clinical trialing

State of the Art Review: Emerging Therapies: The Use of Insulin Sensitizers in the Treatment of Adolescents with Polycystic Ovary Syndrome (PCOS)

PCOS, a heterogeneous disorder characterized by cystic ovarian morphology, androgen excess, and/or irregular periods, emerges during or shortly after puberty. Peri- and post-pubertal obesity, insulin resistance and consequent hyperinsulinemia are highly prevalent co-morbidities of PCOS and promote an ongoing state of excess androgen. Given the relationship of insulin to androgen excess, reduction of insulin secretion and/or improvement of its action at target tissues offer the possibility of improving the physical stigmata of androgen excess by correction of the reproductive dysfunction and preventing metabolic derangements from becoming entrenched. While lifestyle changes that concentrate on behavioral, dietary and exercise regimens should be considered as first line therapy for weight reduction and normalization of insulin levels in adolescents with PCOS, several therapeutic options are available and in wide use, including oral contraceptives, metformin, thiazolidenediones and spironolactone. Overwhelmingly, the data on the safety and efficacy of these medications derive from the adult PCOS literature. Despite the paucity of randomized control trials to adequately evaluate these modalities in adolescents, their use, particularly that of metformin, has gained popularity in the pediatric endocrine community. In this article, we present an overview of the use of insulin sensitizing medications in PCOS and review both the adult and (where available) adolescent literature, focusing specifically on the use of metformin in both mono- and combination therapy