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1.
Indian J Orthop ; 55(Suppl 1): 110-118, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-34122763

RESUMEN

BACKGROUND: Hallux valgus is a common foot deformity that leads to functional disability with serious sequelae. Minimally invasive surgery is often used to treat hallux valgus in order to reduce wound complications and improve recovery time. The objective of this study was to compare a Simple, Effective, Rapid, Inexpensive (SERI) technique with a simple Chevron technique in patients with minimum of 1-year follow-up. METHODS AND MATERIALS: Between the years 2014-2015, we performed a prospective study comparing the SERI minimally invasive technique to treat symptomatic hallux valgus with a standard chevron osteotomy technique. All procedures were performed by a single fellowship trained foot and ankle surgeon. Twenty-one patients were randomized to the SERI cohort and 15 to the standard Chevron technique. RESULTS: The mean preoperative intermetatarsal angle (IMA) of the SERI group was 14.8 ± 1.9 (11.9-22.9). The mean preoperative IMA of the Chevron control group was 13.3 ± 2.3 (10.4-18.2) (p = 0.038). The mean IMA two weeks after the surgery was 6.0 ± 2.3 (2.4-12) in the SERI group, and 6.1 ± 3 (2.6-13.1) in the control group. At the two-week and 1-year follow-up, there was no significant difference found in the IMA between the two groups (p = 0.871). The mean hallux valgus angle reduction was 11.85 ± 4.88 (3-20.8) and 11.09 ± 6.51 (- 1.1 to 22.5) in the SERI and Chevron groups, respectively (p = 0.69). Neither groups reported symptomatic transfer metatarsalgia throughout the follow-up period. The SERI group had increased metatarsophalangeal joint (MTPJ) motion (p < 0.001); however, all other parameters with similar. CONCLUSION: The SERI technique provided comparable outcomes at up to 1-year follow-up when compared with a standard Chevron osteotomy for moderate hallux valgus. This study demonstrated good reproducible results using the SERI technique for moderate hallux valgus. LEVEL OF EVIDENCE: Level II Prospective Study. TRIAL REGISTRATION: Approved by local IRB at MMC.

2.
Transl Psychiatry ; 10(1): 39, 2020 01 27.
Artículo en Inglés | MEDLINE | ID: mdl-32066685

RESUMEN

Angelman syndrome (AS) is a rare neurodevelopmental disorder characterized by developmental delay, impaired communication, motor deficits and ataxia, intellectual disabilities, microcephaly, and seizures. The genetic cause of AS is the loss of expression of UBE3A (ubiquitin protein ligase E6-AP) in the brain, typically due to a deletion of the maternal 15q11-q13 region. Previous studies have been performed using a mouse model with a deletion of a single exon of Ube3a. Since three splice variants of Ube3a exist, this has led to a lack of consistent reports and the theory that perhaps not all mouse studies were assessing the effects of an absence of all functional UBE3A. Herein, we report the generation and functional characterization of a novel model of Angelman syndrome by deleting the entire Ube3a gene in the rat. We validated that this resulted in the first comprehensive gene deletion rodent model. Ultrasonic vocalizations from newborn Ube3am-/p+ were reduced in the maternal inherited deletion group with no observable change in the Ube3am+/p- paternal transmission cohort. We also discovered Ube3am-/p+ exhibited delayed reflex development, motor deficits in rearing and fine motor skills, aberrant social communication, and impaired touchscreen learning and memory in young adults. These behavioral deficits were large in effect size and easily apparent in the larger rodent species. Low social communication was detected using a playback task that is unique to rats. Structural imaging illustrated decreased brain volume in Ube3am-/p+ and a variety of intriguing neuroanatomical phenotypes while Ube3am+/p- did not exhibit altered neuroanatomy. Our report identifies, for the first time, unique AS relevant functional phenotypes and anatomical markers as preclinical outcomes to test various strategies for gene and molecular therapies in AS.


Asunto(s)
Síndrome de Angelman , Discapacidad Intelectual , Síndrome de Angelman/genética , Animales , Eliminación de Gen , Discapacidad Intelectual/genética , Memoria , Ratas , Ubiquitina-Proteína Ligasas/genética
4.
Leukemia ; 32(2): 303-312, 2018 02.
Artículo en Inglés | MEDLINE | ID: mdl-28751770

RESUMEN

Targeted therapies are frequently combined with standard cytotoxic drugs to enhance clinical response. Targeting the B-cell lymphoma 2 (BCL-2) family of proteins is an attractive option to combat chemoresistance in leukemia. Preclinical and clinical studies indicate modest single-agent activity with selective BCL-2 inhibitors (for example, venetoclax). We show that venetoclax synergizes with cytarabine and idarubicin to increase antileukemic efficacy in a TP53-dependent manner. Although TP53 deficiency impaired sensitivity to combined venetoclax and chemotherapy, higher-dose idarubicin was able to suppress MCL1 and induce cell death independently of TP53. Consistent with an MCL1-specific effect, cell death from high-dose idarubicin was dependent on pro-apoptotic Bak. Combining higher-dose idarubicin with venetoclax was able to partially overcome resistance in Bak-deficient cells. Using inducible vectors and venetoclax to differentially target anti-apoptotic BCL-2 family members, BCL-2 and MCL1 emerged as critical and complementary proteins regulating cell survival in acute myeloid leukemia. Dual targeting of BCL-2 and MCL1, but not either alone, prolonged survival of leukemia-bearing mice. In conclusion, our findings support the further investigation of venetoclax in combination with standard chemotherapy, including intensified doses of idarubicin. Venetoclax should also be investigated in combination with direct inhibitors of MCL1 as a chemotherapy-free approach in the future.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Compuestos Bicíclicos Heterocíclicos con Puentes/farmacología , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/metabolismo , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/metabolismo , Sulfonamidas/farmacología , Animales , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Humanos , Idarrubicina/farmacología , Ratones , Ratones Endogámicos NOD , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo
5.
J Child Orthop ; 12(6): 614-621, 2018 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-30607209

RESUMEN

PURPOSE: The incidence of paediatric fractures is known to peak during the summer as a consequence of unsupervised physical activity. A more sedentary lifestyle is a potential cause for changes in paediatric seasonal fracture frequency and severity. The aim of this study was to evaluate the current seasonal variations of paediatric fractures in order to determine resource allocation in hospitals, community clinics and prevention programs. METHODS: A single institutional review of historical data of all patients aged 0 to 16 years that were diagnosed with fractures between April 2014 and July 2017 in the emergency department of a level 3 orthopaedic trauma centre was conducted. In all, 3484 fractures were reviewed, of which 2991 were included. We stratified fractures according to patients' variants and the hour, day and month with respect to holidays, weekends and weather. RESULTS: While the fracture rate on school days was 6.62 per day, the fracture rate during the summer vacation was 4.45 (p < 0.01). Hot weather was correlated with low fracture rates. The peak hours of admission were 12:00 to 13:00 and 18:00 to 22:00, with more moderate differences during non-school periods. CONCLUSION: The local seasonal variation of paediatric fractures has a bimodal distribution, with similar nadirs during both summer and winter. These rates might reflect a shift to a more sedentary lifestyle during the summer vacation. The presented data can assist in improving the value of injury prevention measures and medical resources allocation. LEVEL OF EVIDENCE: II.

6.
Oncogene ; 36(35): 4953-4962, 2017 08 31.
Artículo en Inglés | MEDLINE | ID: mdl-28436946

RESUMEN

Protein synthesis is crucial for regulating cell homeostasis and, when unrestricted, it can lead to tumorigenesis. Immunotoxins derived from Pseudomonas exotoxin are antibody-toxin fusion proteins that inhibit protein synthesis of mammalian cells via ADP-ribosylation of the eukaryotic elongation factor-2. Here we investigate the role of the Bcl-2 family proteins in the response of cancer cells to immunotoxin challenge. Besides the well-known reduction of the prosurvival Bcl-2 family member, Mcl-1, following inhibition of protein synthesis, we show for the first time that immunotoxins also reduce the levels of selected proapoptotic BH-3-only proteins. Among these, only Bim protein levels correlated with the ability of immunotoxins to induce an apoptotic response. To support our findings, we verified that a Bim knockout completely abolished immunotoxin-mediated apoptosis. Further, mice bearing either wild-type or Bid knockout tumors responded to immunotoxin treatment with a decrease in growth kinetics, whereas mice engrafted with Bim knockout tumors showed no reduction in tumor size or prolongation of survival following immunotoxin treatment. From these results, we conclude that Bim expression is a major susceptibility factor for tumor cell death and, as such, constitutes a potential biomarker that could be evaluated before immunotoxin treatment. In support of this hypothesis, clinically, we analyzed patient cells before immunotoxin treatment and report that samples of hairy cell leukemia with high levels of Bim protein responded with a greater decrease in leukemic cell count compared with those samples expressing a low level of Bim.


Asunto(s)
Proteína 11 Similar a Bcl2/metabolismo , Inmunotoxinas/farmacología , Neoplasias/tratamiento farmacológico , Animales , Apoptosis/efectos de los fármacos , Proteína 11 Similar a Bcl2/deficiencia , Proteína 11 Similar a Bcl2/genética , Caspasas/metabolismo , Línea Celular Tumoral , Femenino , Técnicas de Inactivación de Genes , Células HCT116 , Humanos , Ratones , Ratones Desnudos , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patología , Inhibidores de la Síntesis de la Proteína/farmacología , Ensayos Antitumor por Modelo de Xenoinjerto
7.
Leukemia ; 30(7): 1531-41, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-27055867

RESUMEN

The BET (bromodomain and extraterminal domain) bromodomain-containing proteins, such as BRD4, are highly promising targets for treating lymphoid and myeloid malignancies. They act to modulate the expression of multiple genes that control diverse cellular processes including proliferation, survival and differentiation that are consequentially disrupted by small-molecule BET bromodomain inhibitors such as JQ1. By assessing the impact of these inhibitors on normal mouse hematopoietic cells or their transformed counterparts, we establish definitively that their cytotoxic action in vitro and in vivo relies predominantly on the activation of BAX/BAK-dependent mitochondrial (intrinsic) apoptosis. In large part, this is triggered by marked upregulation of the BH3-only protein BIM when the BET inhibitors suppress miR-17-92, a key post-transcriptional repressor of BIM expression. Thus, our study strongly suggests that mutations that permit the evasion of apoptosis (for example, BCL2 overexpression, BIM inactivation) are likely to blunt the activity of the BET bromodomain inhibitors and should be anticipated when therapy resistance develops. Strikingly, we also found that certain normal hematopoietic cells, especially those of lymphoid origin, are as prone to apoptosis induced by the BET inhibitors as their transformed counterparts, indicating that their susceptibility to BET inhibitors did not arise from oncogenic transformation.


Asunto(s)
Apoptosis , Azepinas/farmacología , Proteína 11 Similar a Bcl2/fisiología , Linfoma/patología , MicroARNs/antagonistas & inhibidores , Factores de Transcripción/antagonistas & inhibidores , Triazoles/farmacología , Animales , Apoptosis/efectos de los fármacos , Apoptosis/genética , Proteínas de Ciclo Celular , Línea Celular , Línea Celular Transformada , Modelos Animales de Enfermedad , Sistema Hematopoyético/citología , Historia Antigua , Humanos , Ratones , Ratones Transgénicos , Proteínas Nucleares/antagonistas & inhibidores , ARN Largo no Codificante
8.
Phys Rev Lett ; 116(14): 143002, 2016 04 08.
Artículo en Inglés | MEDLINE | ID: mdl-27104702

RESUMEN

We report the laser cooling of a single ^{40}Ca^{+} ion in a Penning trap to the motional ground state in one dimension. Cooling is performed in the strong binding limit on the 729-nm electric quadrupole S_{1/2}↔D_{5/2} transition, broadened by a quench laser coupling the D_{5/2} and P_{3/2} levels. We find the final ground-state occupation to be 98(1)%. We measure the heating rate of the trap to be very low with n[over ¯][over ˙]≈0.3(2) s^{-1} for trap frequencies from 150-400 kHz, consistent with the large ion-electrode distance.

9.
Regul Toxicol Pharmacol ; 72(1): 94-101, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25777839

RESUMEN

Regulatory agencies often utilize results from peer reviewed publications for hazard assessments. A problem in doing so is the lack of well-accepted tools to objectively, efficiently and systematically assess the quality of published toxicological studies. Herein, we evaluated the publicly available software-based ToxRTool (Toxicological data Reliability assessment Tool) for use in human health hazard assessments. The ToxRTool was developed by the European Commission's Joint Research Center in 2009. It builds on Klimisch categories, a rating system established in 1997, by providing additional criteria and guidance for assessing the reliability of toxicological studies. It also transparently documents the study-selection process. Eight scientists used the ToxRTool to rate the same 20 journal articles on thyroid toxicants. Results were then compared using the Finn coefficient and "AC1" to determine inter-rater consistency. Ratings were most consistent for high-quality journal articles, but less consistent as study quality decreased. Primary reasons for inconsistencies were that some criteria were subjective and some were not clearly described. It was concluded, however, that the ToxRTool has potential and, with refinement, could provide a more objective approach for screening published toxicology studies for use in health risk evaluations, although the ToxRTool ratings are primarily based on study reporting quality.


Asunto(s)
Sustancias Peligrosas/toxicidad , Evaluación del Impacto en la Salud/métodos , Evaluación del Impacto en la Salud/normas , Investigación/normas , Toxicología/métodos , Toxicología/normas , Humanos , Reproducibilidad de los Resultados , Programas Informáticos
10.
Br J Pharmacol ; 171(2): 438-51, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24117225

RESUMEN

BACKGROUND AND PURPOSE: Selective nociceptor fibre block is achieved by introducing the cell membrane impermeant sodium channel blocker lidocaine N-ethyl bromide (QX-314) through transient receptor potential V1 (TRPV1) channels into nociceptors. We screened local anaesthetics for their capacity to activate TRP channels, and characterized the nerve block obtained by combination with QX-314. EXPERIMENTAL APPROACH: We investigated TRP channel activation in dorsal root ganglion (DRG) neurons by calcium imaging and patch-clamp recordings, and cellular QX-314 uptake by MS. To characterize nerve block, compound action potential (CAP) recordings from isolated nerves and behavioural responses were analysed. KEY RESULTS: Of the 12 compounds tested, bupivacaine was the most potent activator of ruthenium red-sensitive calcium entry in DRG neurons and activated heterologously expressed TRPA1 channels. QX-314 permeated through TRPA1 channels and accumulated intracellularly after activation of these channels. Upon sciatic injections, QX-314 markedly prolonged bupivacaine's nociceptive block and also extended (to a lesser degree) its motor block. Bupivacaine's blockade of C-, but not A-fibre, CAPs in sciatic nerves was extended by co-application of QX-314. Surprisingly, however, this action was the same in wild-type, TRPA1-knockout and TRPV1/TRPA1-double knockout mice, suggesting a TRP-channel independent entry pathway. Consistent with this, high doses of bupivacaine promoted a non-selective, cellular uptake of QX-314. CONCLUSIONS AND IMPLICATIONS: Bupivacaine, combined with QX-314, produced a long-lasting sensory nerve block. This did not require QX-314 permeation through TRPA1, although bupivacaine activated these channels. Regardless of entry pathway, the greatly extended duration of block produced by QX-314 and bupivacaine may be clinically useful.


Asunto(s)
Anestésicos Locales/farmacología , Bupivacaína/farmacología , Lidocaína/análogos & derivados , Bloqueo Nervioso , Bloqueadores de los Canales de Sodio/metabolismo , Anestésicos Locales/administración & dosificación , Animales , Conducta Animal/efectos de los fármacos , Bupivacaína/administración & dosificación , Calcio/metabolismo , Línea Celular , Traumatismos de los Pies , Ganglios Espinales/efectos de los fármacos , Ganglios Espinales/metabolismo , Inyecciones , Lidocaína/metabolismo , Masculino , Ratones Noqueados , Técnicas de Placa-Clamp , Nervios Periféricos/efectos de los fármacos , Cultivo Primario de Células , Ratas , Ratas Sprague-Dawley , Nervio Ciático/efectos de los fármacos , Canal Catiónico TRPA1 , Canales de Potencial de Receptor Transitorio/genética , Canales de Potencial de Receptor Transitorio/metabolismo
11.
S Afr Med J ; 103(7): 458-60, 2013 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-23802207

RESUMEN

INTRODUCTION: The need for more cost-effective insulin therapy is critical in reducing the burden on patients and health systems. Biosimilar insulins have the potential to dramatically lower healthcare costs by delivering insulin with a similar anti-glycaemic effect and adverse reaction profile. OBJECTIVES: The purpose of this study was to confirm equivalence in glycaemic outcomes and side-effect profiles between Biosulin 30/70 and other human premixed insulin preparations on the South African market in a clinical practice setting. METHODS: Subjects in this interventional, observational, multicentre, open-label, prospective study were switched from their existing human premix insulin (Actraphane, Humulin 30/70 or Insuman) to the study insulin Biosulin 30/70. The primary endpoint was the change in HbA1c from baseline to 6 months. RESULTS: Seventy-seven adult patients with type 1(n=18) or type 2 (n=59) diabetes were enrolled. The baseline HbA1c in the overall cohort was 7.9%, 8.0% at 3 months (p=0.50) and 7.6% at 6 months (p=0.14).There was a small increase in the total daily dose of insulin used in both the type 1 and type 2 cohort, from 0.62 to 0.65 units/kg/day (p=0.0004). There was no significant difference in weight in the study subjects during the 6-month period on Biosulin 30/70 (p=0.67). CONCLUSION: Biosulin 30/70 achieved at least equivalent glycaemic control to existing human premix insulins, with no reported new or severe adverse events. Increased use of biosimilar insulins has the potential for significant cost savings.


Asunto(s)
Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Hipoglucemiantes/uso terapéutico , Insulina/uso terapéutico , Adulto , Anciano , Estudios de Cohortes , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Femenino , Hemoglobina Glucada/metabolismo , Humanos , Hipoglucemiantes/farmacocinética , Insulina/farmacocinética , Masculino , Persona de Mediana Edad , Sudáfrica , Equivalencia Terapéutica , Resultado del Tratamiento
12.
S Afr Med J ; 103(7): 461-3, 2013 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-23802208

RESUMEN

BACKGROUND: Postprandial glucose excursions contribute significantly to average blood glucose, glycaemic variability and cardiovascular risk. Carbohydrate counting is a method of insulin dosing that balances carbohydrate load to insulin dose using a fixed ratio. Many patients and current insulin pumps calculate insulin delivery for meals based on a linear carbohydrate-to-insulin relationship. It is our hypothesis that a non-linear relationship exists between the amounts of carbohydrate consumed and the insulin required to cover it. AIM: To document blood glucose exposure in response to increasing carbohydrate loads on fixed carbohydrate-to-insulin ratios. METHODS: Five type 1 diabetic subjects receiving insulin pump therapy with good control were recruited. Morning basal rates and carbohydrate- to-insulin ratios were optimised. A Medtronic glucose sensor was used for 5 days to collect data for area-under-the-curve (AUC) analysis, during which standardised meals of increasing carbohydrate loads were consumed. RESULTS: Increasing carbohydrate loads using a fixed carbohydrate-to-insulin ratio resulted in increasing glucose AUC. The relationship was found to be exponential rather than linear. Late postprandial hypoglycaemia followed carbohydrate loads of >60 g and this was often followed by rebound hyperglycaemia that lasted >6 hours. CONCLUSION: A non-linear relationship exists between carbohydrates consumed and the insulin required to cover them. This has implications for control of postprandial blood sugars, especially when consuming large carbohydrate loads. Further studies are required to look at the optimal ratios, duration and type of insulin boluses required to cover increasing carbohydrate loads.


Asunto(s)
Glucemia/metabolismo , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Carbohidratos de la Dieta/administración & dosificación , Hipoglucemiantes/uso terapéutico , Insulina/uso terapéutico , Adolescente , Adulto , Área Bajo la Curva , Estudios de Cohortes , Carbohidratos de la Dieta/metabolismo , Femenino , Humanos , Masculino , Periodo Posprandial/fisiología , Adulto Joven
14.
Neurobiol Dis ; 46(3): 663-72, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22449754

RESUMEN

An increasing body of evidence indicates a role for oligomers of the amyloid-ß peptide (Aß) in the neurotoxicity of this peptide and the pathology of Alzheimer's disease (AD). Several neurotoxic oligomeric forms of Aß have been noted ranging from the larger Amyloid ß-Derived Diffusible Ligands (ADDLs) to smaller trimers and dimers of Aß. More recently a dodecameric form of Aß with a 56 kDa molecular weight, denoted Aß*56, was shown to cause memory impairment in AD model mice. Here, we present for the first time a potential therapeutic strategy for AD that targets the early stages in the formation of neurotoxic Aß*56 oligomers using a modified quinone-Tryptophan small molecule N-(3-chloro-1,4-dihydro-1,4-dioxo-2-naphthalenyl)-L-Tryptophan (Cl-NQTrp). Using NMR spectroscopy we show that this compound binds the aromatic recognition core of Aß and prevents the formation of oligomers. We assessed the effect of Cl-NQTrp in vivo in transgenic flies expressing Aß(1-42) in their nervous system. When these flies were fed with Cl-NQTrp a marked alleviation of their Aß-engendered reduced life span and defective locomotion was observed. Finally, intraperitoneal injection of Cl-NQTrp into an aggressive AD mouse model reduced the level of the Aß*56 species in their brain and reversed their cognitive defects. Further experiments should assess whether this is a direct effect of the drug in the brain or an indirect peripheral effect. This is the first demonstration that targeted reduction of Aß*56 results in amelioration of AD symptoms. This second generation of tryptophan-modified naphthoquinones could therefore serve as potent disease modifying therapeutic for AD.


Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Péptidos beta-Amiloides/antagonistas & inhibidores , Péptidos beta-Amiloides/metabolismo , Cognición/efectos de los fármacos , Naftalenos/farmacología , Fármacos Neuroprotectores/farmacología , Triptófano/análogos & derivados , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/psicología , Animales , Animales Modificados Genéticamente , Benzotiazoles , Barrera Hematoencefálica/metabolismo , Química Encefálica/efectos de los fármacos , Drosophila/metabolismo , Colorantes Fluorescentes , Humanos , Longevidad/efectos de los fármacos , Espectroscopía de Resonancia Magnética , Masculino , Ratones , Ratones Transgénicos , Microscopía Electrónica de Transmisión , Modelos Moleculares , Actividad Motora/efectos de los fármacos , Neurofibrillas/efectos de los fármacos , Neurofibrillas/patología , Desempeño Psicomotor/efectos de los fármacos , Reconocimiento en Psicología/efectos de los fármacos , Tiazoles , Triptófano/farmacología
15.
Curr Top Med Chem ; 10(6): 638-56, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20337589

RESUMEN

In silico drug discovery is a complex process requiring flexibility and ingenuity in method selection and a careful validation of work protocols. GPCR in silico drug discovery poses additional challenges due to the paucity of crystallographic data. This paper starts by reviewing selected GPCR in silico screening programs reported in the literature, including both structure-based and ligand-based approaches. Particular emphasis is given to library design, binding mode selection, process validation and compound selection for biological testing. Following literature review, we provide insights into in silico methodologies and process workflows used at EPIX to drive over 20 highly successful screening and lead optimization programs performed since 2001. Applications of the various methodologies discussed are demonstrated by examples from recent programs that have not yet been published.


Asunto(s)
Descubrimiento de Drogas , Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Diseño de Fármacos , Ligandos , Modelos Moleculares , Relación Estructura-Actividad
16.
Rev Sci Instrum ; 81(1): 013111, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20113085

RESUMEN

We report on the design and testing of an array of Penning ion traps made from printed circuit board. The system enables fast shuttling of ions from one trapping zone to another, which could be of use in quantum information processing. We describe simulations carried out to determine the optimal potentials to be applied to the trap electrodes for enabling this movement. The results of a preliminary experiment with a cloud of laser cooled calcium ions demonstrate a round-trip shuttling efficiency of up to 75%.

17.
Prenat Diagn ; 29(12): 1130-4, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19777489

RESUMEN

BACKGROUND: Current risk calculations for trisomy 21, which are based on multiples of median (MoM), do not take into account possible differences between euploid and trisomy 21 pregnancies that may develop with gestational age. In order to optimize the predictive value of screening tests, we calculated the ratio between maternal serum concentration of alpha-fetoprotein (AFP) and that of human chorionic gonadotropin (hCG) in euploid and in trisomy 21 pregnancies. METHODS: The medians of the concentration ratios, [AFP]/[hCG] at 16-21 weeks of gestation, were plotted as a function of gestational age for 307 cases of trisomy 21 and were compared with the medians of 30 549 normal karyotype cases. RESULTS: [AFP]/[hCG] ratio medians were independent of body weight and maternal age. There was a significant difference in the [AFP]/[hCG] ratio when comparing trisomy 21 and euploid pregnancies at each week. This difference became greater with advancing gestational age (P < 0.01). CONCLUSION: There is a significant difference in ratios of [AFP]/[hCG] between euploid and trisomy 21 pregnancies, which may be used to improve detection rates of Down syndrome screening.


Asunto(s)
Gonadotropina Coriónica/sangre , Síndrome de Down/sangre , Edad Gestacional , Madres , alfa-Fetoproteínas/análisis , Adulto , Gonadotropina Coriónica/análisis , Síndrome de Down/diagnóstico , Femenino , Humanos , Ploidias , Embarazo , Diagnóstico Prenatal , Estudios Retrospectivos , Sensibilidad y Especificidad
18.
Int J Obes (Lond) ; 33(10): 1153-65, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19636319

RESUMEN

OBJECTIVE: Skeletal muscle produces a variety of secreted proteins that have important roles in intercellular communication and affects processes such as glucose homoeostasis. The objective of this study was to develop a novel Signal Sequence Trap (SST) in conjunction with cDNA microarray technology to identify proteins secreted from skeletal muscle of Psammomys obesus that were associated with obesity and type 2 diabetes (T2D). DESIGN: Secreted proteins that were differentially expressed between lean, normal glucose tolerant (NGT), overweight and impaired glucose tolerant (IGT) and obese, T2D P. obesus were isolated using SST in conjunction with cDNA microarray technology. Subsequent gene expression was measured in tissues from P. obesus by real-time PCR (RT-PCR). RESULTS: The SST yielded 1600 positive clones, which were screened for differential expression. A total of 91 (approximately 6%) clones were identified by microarray to be differentially expressed between NGT, IGT and T2D P. obesus. These clones were sequenced to identify 51 genes, of which only 27 were previously known to encode secreted proteins. Three candidate genes not previously associated with obesity or type 2 diabetes, sushi domain containing 2, collagen and calcium-binding EGF domains 1 and periostin (Postn), as well as one gene known to be associated, complement component 1, were shown by RT-PCR to be differentially expressed in skeletal muscle of P. obesus. Further characterization of the secreted protein Postn revealed it to be predominantly expressed in adipose tissue, with higher expression in visceral compared with subcutaneous adipose depots. CONCLUSION: SST in conjunction with cDNA microarray technology is a powerful tool to identify differentially expressed secreted proteins involved in complex diseases such as obesity and type 2 diabetes. Furthermore, a number of candidate genes were identified, in particular, Postn, which may have a role in the development of obesity and type 2 diabetes.


Asunto(s)
Diabetes Mellitus Tipo 2/metabolismo , Proteínas Musculares/análisis , Músculo Esquelético/metabolismo , Obesidad/metabolismo , Animales , Expresión Génica/genética , Gerbillinae , Masculino , Análisis por Micromatrices/métodos , Datos de Secuencia Molecular , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Análisis por Matrices de Proteínas/métodos
19.
Cytogenet Genome Res ; 124(3-4): 327-38, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19556784

RESUMEN

Extrachromosomal circular DNA (eccDNA) is ubiquitous in eukaryotic organisms, and has been noted for more than 3 decades. eccDNA occurs in normal tissues and in cultured cells, is heterogeneous in size, consists of chromosomal sequences and reflects plasticity of the genome. Two-dimensional (2D) gel electrophoresis has been adapted for the detection and characterization of eccDNA. It shows that most eccDNA consists of chromosomal tandem repeats, both coding genes and satellite DNA and is organized as circular multimers of the repeating sequence. 2D gels were unable to detect dispersed repeats within the population of eccDNA. eccDNA, organized as circular multimers, can be formed de novo in Xenopus egg extracts, in the absence of DNA replication. These findings support a mechanism for the formation of eccDNA that involves intra-chromosomal homologous recombination between tandem repeats and looping-out. Furthermore, eccDNA appears to undergo extrachromosomal replication via a rolling circle mechanism. Hence, the formation of eccDNA from arrays of tandem repeats may cause deletions, and the possible re-integration of rolling-circle replication products could expand these arrays. This review summarizes recent experimental data which characterizes eccDNA in several organisms using 2D gel electrophoresis, and discusses its possible implications on the dynamics of chromosomal tandem repeats.


Asunto(s)
Cromosomas/fisiología , Replicación del ADN/fisiología , ADN Circular/fisiología , ADN Satélite/fisiología , Secuencias Repetidas en Tándem/fisiología , Animales , ADN Circular/química , Humanos
20.
Leukemia ; 23(8): 1446-54, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19322212

RESUMEN

Omacetaxine mepesuccinate (formerly homoharringtonine) is a molecule with a mechanism of action that is different from tyrosine kinase inhibitors, and its activity in chronic myeloid leukemia (CML) seems to be independent of the BCR-ABL mutation status. Using BCR-ABL-expressing myelogenous and lymphoid cell lines and mouse models of CML and B-cell acute lymphoblastic leukemia (B-ALL) induced by wild-type BCR-ABL or T315I mutant-BCR-ABL, we evaluated the inhibitory effects of omacetaxine on CML and B-ALL. We showed that more than 90% of the leukemic stem cells were killed after treatment with omacetaxine in vitro. In contrast, less than 9 or 25% of the leukemic stem cells were killed after treating with imatinib or dasatinib, respectively. After 4 days of treatment of CML mice with omacetaxine, Gr-1(+)myeloid leukemia cells decreased in the peripheral blood of the treated CML mice. In the omacetaxine-treated B-ALL mice, only 0.8% of the B220(+)leukemia cells were found in peripheral blood, compared with 34% of the B220(+)leukemia cells in the placebo group. Treatment with omacetaxine decreased the number of leukemia stem cells and prolonged the survival of mice with BCR-ABL-induced CML or B-ALL.


Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Harringtoninas/farmacología , Leucemia de Células B/tratamiento farmacológico , Leucemia Mielógena Crónica BCR-ABL Positiva/patología , Células Madre Neoplásicas/efectos de los fármacos , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patología , Animales , Antineoplásicos Fitogénicos/uso terapéutico , Línea Celular Tumoral/efectos de los fármacos , Proteínas de Fusión bcr-abl/genética , Proteínas de Fusión bcr-abl/fisiología , Regulación Leucémica de la Expresión Génica/efectos de los fármacos , Proteínas HSP90 de Choque Térmico/biosíntesis , Proteínas HSP90 de Choque Térmico/genética , Harringtoninas/uso terapéutico , Homoharringtonina , Humanos , Células K562/efectos de los fármacos , Leucemia de Células B/sangre , Leucemia de Células B/patología , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Quimera por Radiación , Proteínas Recombinantes de Fusión/fisiología , Transducción Genética
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