137 research outputs found
Mechanics of Tunable Helices and Geometric Frustration in Biomimetic Seashells
Helical structures are ubiquitous in nature and engineering, ranging from DNA
molecules to plant tendrils, from sea snail shells to nanoribbons. While the
helical shapes in natural and engineered systems often exhibit nearly uniform
radius and pitch, helical shell structures with changing radius and pitch, such
as seashells and some plant tendrils, adds to the variety of this family of
aesthetic beauty. Here we develop a comprehensive theoretical framework for
tunable helical morphologies, and report the first biomimetic seashell-like
structure resulting from mechanics of geometric frustration. In previous
studies, the total potential energy is everywhere minimized when the system
achieves equilibrium. In this work, however, the local energy minimization
cannot be realized because of the geometric incompatibility, and hence the
whole system deforms into a shape with a global energy minimum whereby the
energy in each segment may not necessarily be locally optimized. This novel
approach can be applied to develop materials and devices of tunable geometries
with a range of applications in nano/biotechnology
A molecular biology and phase II trial of lapatinib in children with refractory CNS malignancies: a pediatric brain tumor consortium study.
High expression of ERBB2 has been reported in medulloblastoma and ependymoma; EGFR is amplified and over-expressed in brainstem glioma suggesting these proteins as potential therapeutic targets. We conducted a molecular biology (MB) and phase II study to estimate inhibition of tumor ERBB signaling and sustained responses by lapatinib in children with recurrent CNS malignancies. In the MB study, patients with recurrent medulloblastoma, ependymoma, and high-grade glioma (HGG) undergoing resection were stratified and randomized to pre-resection treatment with lapatinib 900 mg/m(2) dose bid for 7-14 days or no treatment. Western blot analysis of ERBB expression and pathway activity in fresh tumor obtained at surgery estimated ERBB receptor signaling inhibition in vivo. Drug concentration was simultaneously assessed in tumor and plasma. In the phase II study, patients, stratified by histology, received lapatinib continuously, to assess sustained response. Eight patients, on the MB trial (four medulloblastomas, four ependymomas), received a median of two courses (range 1-6+). No intratumoral target inhibition by lapatinib was noted in any patient. Tumor-to-plasma ratios of lapatinib were 10-20 %. In the 34 patients (14 MB, 10 HGG, 10 ependymoma) in the phase II study, lapatinib was well-tolerated at 900 mg/m(2) dose bid. The median number of courses in the phase II trial was two (range 1-12). Seven patients (three medulloblastoma, four ependymoma) remained on therapy for at least four courses range (4-26). Lapatinib was well-tolerated in children with recurrent or CNS malignancies, but did not inhibit target in tumor and had little single agent activity.Fil: Fouladi, Maryam. St. Jude Children’s Research Hospital; Estados UnidosFil: Stewart, Clinton F.. St. Jude Children’s Research Hospital; Estados UnidosFil: Blaney, Susan M.. Baylor College of Medicine. Texas Children’s Cancer Center; Estados UnidosFil: Onar Thomas, Arzu. St. Jude Children’s Research Hospital; Estados UnidosFil: Schaiquevich, Paula Susana. St. Jude Children’s Research Hospital; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Packer, Roger J.. Children’s National Medical Center; Estados UnidosFil: Goldman, Stewart. Anne and Robert H. Lurie Children’s Hospital of Chicago; Estados UnidosFil: Geyer, J. Rusell. Children’s Hospital and Regional Medical Center; Estados UnidosFil: Gajjar, Amar. St. Jude Children’s Research Hospital; Estados UnidosFil: Kun, Larry E.. St. Jude Children’s Research Hospital; Estados UnidosFil: Boyett, James M.. St. Jude Children’s Research Hospital; Estados UnidosFil: Gilbertson, Richard J.. St. Jude Children’s Research Hospital; Estados Unido
Modulation of Xenopus oocyte-expressed phospholemman-induced ion currents by co-expression of protein kinases
AbstractPhospholemman (PLM), the major sarcolemmal substrate for phosphorylation by cAMP-dependent kinase (PKA) protein kinase C (PKC) and NIMA kinase in muscle, induces hyperpolarization-activated anion currents in Xenopus oocytes, most probably by enhancing endogenous oocyte currents. PLM peptides from the cytoplasmic tail are phosphorylated by PKA at S68, by NIMA kinase at S63, and by PKC at both S63 and S68. We have confirmed the phosphorylation sites in the intact protein, and we have investigated the role of phosphorylation in the regulatory activity of PLM using oocyte expression experiments. We found: (1) the cytoplasmic domain is not essential for inducing currents in oocytes; (2) co-expression of PKA increased the amplitude of oocyte currents and the amount of PLM in the oocyte membrane largely, but not exclusively, through phosphorylation of S68; (3) co-expression of PKA had no effect on a PLM mutant in which all putative phosphorylation sites had been inactivated by serine to alanine mutation (SSST 62, 63, 68, 69 AAAA); (4) co-expression of PKC had no effect in this system; (5) co-expression of NIMA kinase increased current amplitude and membrane protein level, but did not require PLM phosphorylation. These findings point to a role for phosphorylation in the function of PLM
A knowledge-guided active model method of skull segmentation on T1-weighted MR images
Skull is the anatomic landmark for patient set up of head radiation therapy. Skull is generally segmented from CT images because CT provides better definition of skull than MR imaging. In the mean time, radiation therapy is planned on MR images for soft tissue information. This study utilized a knowledge-guided active model (KAM) method to segmented skull on MR images in order to enable radiation therapy planning with MR images as the primary planning dataset. KAM utilized age-specific skull mesh models that segmented from CT images using a conditional region growing algorithm. Skull models were transformed to given MR images using an affine registration algorithm based on normalized mutual information. The transformed mesh models actively located skull boundaries by minimizing their total energy. The preliminary validation was performed on MR and CT images from five patients. The KAM segmented skulls were compared with those segmented from CT images. The average image similarity (kappa index) was 0.57. The initial validation showed that it was promising to segment skulls directly on MR images using KAM
Plasma p217+tau versus NAV4694 amyloid and MK6240 tau PET across the Alzheimer\u27s continuum
Introduction: We evaluated a new Simoa plasma assay for phosphorylated tau (P-tau) at aa217 enhanced by additional p-tau sites (p217+tau). Methods: Plasma p217+tau levels were compared to 18F-NAV4694 amyloid beta (Aβ) positron emission tomography (PET) and 18F-MK6240 tau PET in 174 cognitively impaired (CI) and 223 cognitively unimpaired (CU) participants. Results: Compared to Aβ− CU, the plasma levels of p217+tau increased 2-fold in Aβ+ CU and 3.5-fold in Aβ+ CI. In Aβ− the p217+tau levels did not differ significantly between CU and CI. P217+tau correlated with Aβ centiloids P =.67 (CI, P =.64; CU, P =.45) and tau SUVRMT P =.63 (CI, P =.69; CU, P =.34). Area under curve (AUC) for Alzheimer\u27s disease (AD) dementia versus Aβ− CU was 0.94, for AD dementia versus other dementia was 0.93, for Aβ+ versus Aβ− PET was 0.89, and for tau+ versus tau− PET was 0.89. Discussion: Plasma p217+tau levels elevate early in the AD continuum and correlate well with Aβ and tau PET
SAWEN SASTRA DESA (MONOGRAF) MARAKATA-BATURAN-MAHACITTA DESA SWABUDAYA BATUAN
Institut Seni Indonesia (ISI) Denpasar menginisiasi program pengabdian masyarakat Nata
Citta Swabudaya (NCS) pada Desa/Desa Adat terpilih di Bali. Program ini sepenuhnya
didedikasikan untuk memajukan seni budaya berbasis kearifan lokal pada lokus
pengabdian masyarakat yang dipilih. Pada program ini, ISI Denpasar terjun dengan tim
terbaik dari unsur-unsur dosen dan tenaga kependidikan lintas Fakultas-lintas Program
Studi (Prodi). Pilihan tim seperti ini dilakukan, guna memastikan seluruh potensi seni
budaya dalam menopang pemajuan ekosistem dapat terakomodasi dengan optimal
sejalan kecakapan dan profesionalisme bidang seni masing-masing anggota tim.
Ekosistem seni budaya di desa/desa adat seluruh Bali secara umum telah berlangsung
turun-temurun dan terpelihara secara baik, namun harus diakui pula bahwa masih
banyak terjadi stagnasi, kerapuhan, bahkan kehilangan ekosistem. Pada beberapa desa,
banyak terjadi kemacetan sistem pewarisan, kelangkaan, dan kepunahan seni budaya
klasik dan tradisi. Antusiasme generasi muda dalam kerja pemajuan seni budaya di desa/
desa adat juga mengalami pemudaran.
Kondisi objektif tersebut, menjadikan kehadiran NCS selalu dinanti desa/desa adat di
Bali. Pada tahun 2022 ini, telah diselenggarakan program NCS di 5 desa/desa adat, yaitu:
Nagasepaha (Buleleng), Penglipuran (Bangli), Batuan (Tabanan), Tenganan Pegringsingan
(Karangasem), dan Batuan (Gianyar).
Pemilihan Desa Batuan selain karena pengajuan oleh Perbekel Desa setempat, hal
terpenting justru menunjuk pada potensi kekayaan seni budaya yang dimiliki. Adapun
potensi seni dimaksud, meliputi: drama tari gambuh, seni lukis khas Batuan, seni pahat
dan topeng, sungging wayang kulit, kerajinan perak dan keris, serta berbagai properti
pagelaran. Selain potensi seni, Desa ini memiliki keistimewaan karena mewarisi berbagai
artefak sakral Bali Kuno, diantaranya: prasasti Baturan, lingga-yoni, dan beragam arca.
Kehidupan sehari-hari masyarakat juga kental dan menyatu dengan tata laku tradisi,
adat, seni budaya, serta kearifan lokal yang diwarisi dari zaman ke zaman. Selain alasan
potensi seni budaya, pada tahun 2022 ini pula dimuliakan perayaan seribu tahun Prasasti
Baturan. Momentum penting ini menjadi pertimbangan tersendiri penyelenggaraan
NCS di desa Batuan.
Potensi objektif ekosistem seni budaya Desa Batuan yang memadai untuk
penyelenggaraan NCS, ternyata gayut harapan dan komitmen Kepala Desa Batuan,
Ari Anggara menyatakan “Desa Batuan sebagai desa yang berbasis seni budaya yang
didukung potensi sumber daya alam yang sangat layak untuk di hidupkan guna
mendukung program-program desa terkait dengan penguatan dan pemajuan potensi
seni budaya tersebut. Menimbang potensi objektif dan antusiasme pihak pengelola desa, maka diputuskan
luaran NCS di Desa Batuan, yaitu: Panyembrama Citta (tari penyambutan), Sasmita Desa
(video profil desa), Sawen Sastra Desa (monografi desa), dan Swabudaya Patra (prasasti
NCS)
Atrasentan and renal events in patients with type 2 diabetes and chronic kidney disease (SONAR): a double-blind, randomised, placebo-controlled trial
Background: Short-term treatment for people with type 2 diabetes using a low dose of the selective endothelin A receptor antagonist atrasentan reduces albuminuria without causing significant sodium retention. We report the long-term effects of treatment with atrasentan on major renal outcomes. Methods: We did this double-blind, randomised, placebo-controlled trial at 689 sites in 41 countries. We enrolled adults aged 18–85 years with type 2 diabetes, estimated glomerular filtration rate (eGFR)25–75 mL/min per 1·73 m 2 of body surface area, and a urine albumin-to-creatinine ratio (UACR)of 300–5000 mg/g who had received maximum labelled or tolerated renin–angiotensin system inhibition for at least 4 weeks. Participants were given atrasentan 0·75 mg orally daily during an enrichment period before random group assignment. Those with a UACR decrease of at least 30% with no substantial fluid retention during the enrichment period (responders)were included in the double-blind treatment period. Responders were randomly assigned to receive either atrasentan 0·75 mg orally daily or placebo. All patients and investigators were masked to treatment assignment. The primary endpoint was a composite of doubling of serum creatinine (sustained for ≥30 days)or end-stage kidney disease (eGFR <15 mL/min per 1·73 m 2 sustained for ≥90 days, chronic dialysis for ≥90 days, kidney transplantation, or death from kidney failure)in the intention-to-treat population of all responders. Safety was assessed in all patients who received at least one dose of their assigned study treatment. The study is registered with ClinicalTrials.gov, number NCT01858532. Findings: Between May 17, 2013, and July 13, 2017, 11 087 patients were screened; 5117 entered the enrichment period, and 4711 completed the enrichment period. Of these, 2648 patients were responders and were randomly assigned to the atrasentan group (n=1325)or placebo group (n=1323). Median follow-up was 2·2 years (IQR 1·4–2·9). 79 (6·0%)of 1325 patients in the atrasentan group and 105 (7·9%)of 1323 in the placebo group had a primary composite renal endpoint event (hazard ratio [HR]0·65 [95% CI 0·49–0·88]; p=0·0047). Fluid retention and anaemia adverse events, which have been previously attributed to endothelin receptor antagonists, were more frequent in the atrasentan group than in the placebo group. Hospital admission for heart failure occurred in 47 (3·5%)of 1325 patients in the atrasentan group and 34 (2·6%)of 1323 patients in the placebo group (HR 1·33 [95% CI 0·85–2·07]; p=0·208). 58 (4·4%)patients in the atrasentan group and 52 (3·9%)in the placebo group died (HR 1·09 [95% CI 0·75–1·59]; p=0·65). Interpretation: Atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease who were selected to optimise efficacy and safety. These data support a potential role for selective endothelin receptor antagonists in protecting renal function in patients with type 2 diabetes at high risk of developing end-stage kidney disease. Funding: AbbVie
Canagliflozin and renal outcomes in type 2 diabetes and nephropathy
BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years
National Cancer Institute Workshop on Proton Therapy for Children: Considerations Regarding Brainstem Injury
PURPOSE: Proton therapy can allow for superior avoidance of normal tissues. A widespread consensus has been reached that proton therapy should be used for patients with curable pediatric brain tumor to avoid critical central nervous system structures. Brainstem necrosis is a potentially devastating, but rare, complication of radiation. Recent reports of brainstem necrosis after proton therapy have raised concerns over the potential biological differences among radiation modalities. We have summarized findings from the National Cancer Institute Workshop on Proton Therapy for Children convened in May 2016 to examine brainstem injury.
METHODS AND MATERIALS: Twenty-seven physicians, physicists, and researchers from 17 institutions with expertise met to discuss this issue. The definition of brainstem injury, imaging of this entity, clinical experience with photons and photons, and potential biological differences among these radiation modalities were thoroughly discussed and reviewed. The 3 largest US pediatric proton therapy centers collectively summarized the incidence of symptomatic brainstem injury and physics details (planning, dosimetry, delivery) for 671 children with focal posterior fossa tumors treated with protons from 2006 to 2016.
RESULTS: The average rate of symptomatic brainstem toxicity from the 3 largest US pediatric proton centers was 2.38%. The actuarial rate of grade \u3e /=2 brainstem toxicity was successfully reduced from 12.7% to 0% at 1 center after adopting modified radiation guidelines. Guidelines for treatment planning and current consensus brainstem constraints for proton therapy are presented. The current knowledge regarding linear energy transfer (LET) and its relationship to relative biological effectiveness (RBE) are defined. We review the current state of LET-based planning.
CONCLUSIONS: Brainstem injury is a rare complication of radiation therapy for both photons and protons. Substantial dosimetric data have been collected for brainstem injury after proton therapy, and established guidelines to allow for safe delivery of proton radiation have been defined. Increased capability exists to incorporate LET optimization; however, further research is needed to fully explore the capabilities of LET- and RBE-based planning
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