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1.
Am Heart J ; 2024 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-39341482

RESUMEN

RATIONALES: Atherosclerotic Cardiovascular Disease (ASCVD) is the leading cause of morbidity and mortality in the United States. Suboptimal control of hypertension and hyperlipidemia are common factors contributing to ASCVD risk. The Penn Medicine Healthy Heart (PMHH) Study is a randomized clinical trial testing the effectiveness of a system designed to offload work from primary care clinicians and improve patient follow-through with risk reduction strategies by using a centralized team of non-clinical navigators and advanced practice providers, remote monitoring, and bi-directional text messaging, augmented by behavioral science engagement strategies. The intervention builds on prior non-randomized evaluations of these design elements that demonstrated significant improvement in patients' systolic blood pressure and LDL Cholesterol (LDL-C). PRIMARY HYPOTHESIS: Penn Medicine Healthy Heart will significantly improve systolic blood pressure and LDL-C compared to usual care over the 6 months of this intervention. DESIGN: Randomized clinical trial of Penn Medicine Healthy Heart in patients aged 35-80 years at elevated risk of ASCVD whose systolic blood pressure and LDL-C are not well controlled. The intervention consists of four modules that address blood pressure management, lipid management, nutrition, and smoking cessation, offered in a phased approach to give the participant time to learn about each topic, adopt any recommendations, and build a relationship with the care team. SITES: University of Pennsylvania Health System at primary care practices located in inner-city urban and rural/semi-rural areas PRIMARY OUTCOMES: Improvement in systolic blood pressure and LDL-C SECONDARY OUTCOMES: Cost-effectiveness analyses are planned to evaluate the health care costs and health outcomes of the intervention approach. An implementation evaluation is planned to understand factors influencing success of the intervention. ESTIMATED ENROLLMENT: 2,420 active patients of Penn Medicine primary care practices who have clinical ASCVD, or who are at elevated risk for ASCVD, and who are (a) not on statins or have LDL-C > 100 despite being on statins and (b) had systolic blood pressure>140 at two recent ambulatory visits. ENROLLMENT DATES: March 2024-March 2025. The intervention will last 6 months with a 12-month follow-up to determine whether its effects persist. CURRENT STATUS: Enrolling (1,240 enrolled as of August 15, 2024) CLINICAL TRIAL REGISTRATION: NCT06062394.

2.
BMC Public Health ; 21(1): 1496, 2021 08 03.
Artículo en Inglés | MEDLINE | ID: mdl-34344340

RESUMEN

BACKGROUND: The BETTER (Building on Existing Tools to Improve Chronic Disease Prevention and Screening in Primary Care) intervention was designed to integrate the approach to chronic disease prevention and screening in primary care and demonstrated effective in a previous randomized trial. METHODS: We tested the effectiveness of the BETTER HEALTH intervention, a public health adaptation of BETTER, at improving participation in chronic disease prevention and screening actions for residents of low-income neighbourhoods in a cluster randomized trial, with ten low-income neighbourhoods in Durham Region Ontario randomized to immediate intervention vs. wait-list. The unit of analysis was the individual, and eligible participants were adults age 40-64 years residing in the neighbourhoods. Public health nurses trained as "prevention practitioners" held one prevention-focused visit with each participant. They provided participants with a tailored prevention prescription and supported them to set health-related goals. The primary outcome was a composite index: the number of evidence-based actions achieved at six months as a proportion of those for which participants were eligible at baseline. RESULTS: Of 126 participants (60 in immediate arm; 66 in wait-list arm), 125 were included in analyses (1 participant withdrew consent). In both arms, participants were eligible for a mean of 8.6 actions at baseline. At follow-up, participants in the immediate intervention arm met 64.5% of actions for which they were eligible versus 42.1% in the wait-list arm (rate ratio 1.53 [95% confidence interval 1.22-1.84]). CONCLUSION: Public health nurses using the BETTER HEALTH intervention led to a higher proportion of identified evidence-based prevention and screening actions achieved at six months for people living with socioeconomic disadvantage. TRIAL REGISTRATION: NCT03052959 , registered February 10, 2017.


Asunto(s)
Tamizaje Masivo , Salud Pública , Adulto , Enfermedad Crónica , Humanos , Persona de Mediana Edad , Ontario , Atención Primaria de Salud
3.
Pediatr Blood Cancer ; 65(3)2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29115718

RESUMEN

BACKGROUND: Young children with posterior fossa ependymoma (PF-EPN) have a worse prognosis than older children, and they have a unique molecular profile (PF-EPN-A subtype). Alternative treatment strategies are often used in these young patients, and their prognostic factors are less clear. METHODS: We characterized the prognostic factors and treatment outcomes of 482 patients between ages 0 and 3 years with the diagnosis of ependymoma identified from the Surveillance, Epidemiology, and End Results registry (1973-2013). RESULTS: Radiation therapy (RT) was delivered to 52.3% of patients, and gross total resection (GTR) was performed in 51.0% of patients. Overall survival (OS) at 10 years was 48.4% with median follow-up of 3.3 years. WHO grade was not predictive of OS. Extent of resection was significant for survival; the 10-year OS with GTR was 61.0%, and with subtotal resection (STR) and biopsy was 38.2% and 35.0%, respectively (P < 0.001). RT significantly benefitted OS for both grades II and III. The 10-year OS for grade II was 50.5% with RT and 43.4% without (P = 0.030); 10-year OS for grade III was 66.0% with RT and 40.0% without (P = 0.002). Multivariate analysis showed significantly improved OS with RT (hazard ratio [HR] 0.601, 95% CI: 0.439-0.820, P = 0.001) and GTR (HR 0.471, 95% CI: 0.328-0.677, P < 0.0001). CONCLUSIONS: Ependymoma outcomes in patients within 0-3 years of age significantly improved with RT and GTR. Histopathologic grading of ependymoma demonstrated no prognostic significance. Given the poor OS for this population and unique genetic profile, future prospective studies with molecular-based stratification should be performed to evaluate additional prognostic factors.


Asunto(s)
Ependimoma/radioterapia , Ependimoma/cirugía , Neoplasias Infratentoriales/radioterapia , Neoplasias Infratentoriales/cirugía , Preescolar , Ependimoma/mortalidad , Femenino , Humanos , Lactante , Recién Nacido , Neoplasias Infratentoriales/mortalidad , Masculino , Pronóstico , Supervivencia sin Progresión , Programa de VERF , Resultado del Tratamiento
5.
R Soc Open Sci ; 10(9): 230790, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37771964

RESUMEN

The COVID-19 pandemic profoundly affected various aspects of daily life, particularly the supply and demand of essential goods, resulting in critical shortages. This included personal protective equipment for medical professionals and the general public. To address these shortages, online 'maker communities' emerged, aiming to develop and locally manufacture critical products. While some organized efforts existed, the majority of initiatives originated from individuals and groups on platforms like Thingiverse. This paper presents a longitudinal analysis of Thingiverse, one of the largest maker community websites, to examine the pandemic's effects. Our findings reveal a surge in community output during the initial lockdown periods in major contributing nations (primarily those in the Western Hemisphere), followed by a subsequent decline. Additionally, throughout 2020, pandemic-related products dominated uploads and interactions during this period. Based on these observations, we propose recommendations to expedite the community's ability to support local, national and international responses to future disasters.

6.
J Med Primatol ; 38(6): 390-6, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19793178

RESUMEN

BACKGROUND: Near patient testing (NPT) and point-of-care testing (POCT) using portable benchtop analyzers has become necessary in many areas of the medical community, including biocontainment. METHODS: We evaluated the Beckman AcT diff, Abaxis Vetscan HMII (two instruments), Abbott Cell-Dyn 1800, and Abaxis Vetscan VS2 for within-run precision and correlation to central laboratory instruments using non-human primates blood. RESULTS: Compared with the central laboratory instruments, the Beckman AcT diff correlated on 80%; the HMII instruments on 31% and 44%, the CD1800 on 31%, and the VS2 on 71% of assays. For assays with published manufacturers precision guidelines, the AcT diff met all nine, the HMII instruments met one and six of six, and the CD 1800 met one of six. CONCLUSIONS: Laboratories using NPT/POCT must test their individual instruments for precision and correlation, identify assays that are reliable, and exclude or develop supplemental procedures for assays that are not.


Asunto(s)
Análisis Químico de la Sangre/instrumentación , Pruebas Hematológicas/instrumentación , Animales , Cercopithecinae/sangre , Femenino , Masculino , Pan troglodytes/sangre , Sistemas de Atención de Punto
7.
Cancer Res ; 42(8 Suppl): 3334s-3337s, 1982 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-7083196

RESUMEN

Various C19-steroidal derivatives have been synthesized and evaluated in biochemical assays for their ability to inhibit the biosynthesis of estrogens. Steroids with substitutions on the A or B ring were prepared by Michael addition of various thiol reagents to appropriate dienone intermediates. An in vitro assay using human placental microsomes was used to evaluate aromatase-inhibitory properties. Synthesized compounds that exhibited high inhibitory activity were further evaluated under initial velocity conditions to determine apparent Ki values. Several 7 alpha-substituted androstenediones were effective competitive inhibitors and have apparent Ki values ranging from 18 to 69 nM, with the apparent Km for androstenedione being 63 nM. The most effective competitive inhibitor tested is 7 alpha-(4'-amino)phenylthioandrost-4-ene-3,17-dione with an apparent Ki of 18 nM. Derivatives of this 7 alpha-thioether compound that contain alkylating moieties have been prepared as potential irreversible enzyme inhibitors and demonstrate varying abilities to inactivate the aromatase enzyme. The results of these studies demonstrate that large chemical functionalities such as an aromatic ring with polar substituents can be accommodated in or near the active site of aromatase and, in some cases, can enhance the affinity of the enzyme for the inhibitors.


Asunto(s)
Androstenodiona/análogos & derivados , Inhibidores de la Aromatasa , Estrógenos/biosíntesis , Oxidorreductasas/antagonistas & inhibidores , Placenta/enzimología , Androstenodiona/farmacología , Femenino , Humanos , Cinética , Microsomas/enzimología , Embarazo
8.
Mol Endocrinol ; 2(3): 263-71, 1988 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-3398853

RESUMEN

We have examined the effects of estrogen and progestin agonist and antagonist ligands on regulation of progesterone receptor (PR) protein and mRNA levels in a variety of human breast cancer cell lines. By Northern blot analysis, using human PR cDNA probes, PR mRNA in T47D and MCF-7 cells appears as five species of approximately 11.4, 5.8, 5.3, 3.5, and 2.8 kilobases. PR mRNA species are not detected in the PR protein-negative breast cancer cell lines MDA-MB-231 and LY2. T47D cells contain high levels of PR mRNA and protein (detected by hormone binding assay or Western blot analysis), and the PR protein and mRNA content of T47D cells are reduced to about 10% of the control level within 48 h of treatment with 10 nM promegestone; 17, 21-dimethyl-19-nor-pregna-4,9-diene-3, 20-dione (R5020) or 16 alpha-ethyl-21-hydroxy-19-nor-pregn-4-ene-3,20-dione (ORG2058), both potent progestins. In contrast, treatment of T47D cells with the antiprogestin 17 beta-hydroxy-11 beta-[4-dimethylaminophenyl]-17 alpha-(1-propynyl)-estra- 4, 9-dien-3-one) (RU38486) reduces PR protein and mRNA levels only transiently. PR protein and mRNA are virtually undetectable in control MCF-7 cells grown in the absence of estrogens. When estradiol is administered to MCF-7 cells, the PR mRNA and protein levels increase gradually and proportionately (10- or 40-fold, respectively, in 3 days).(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Neoplasias de la Mama/genética , ARN Mensajero/fisiología , Receptores de Progesterona/genética , Neoplasias de la Mama/fisiopatología , Estrenos/farmacología , Antagonistas de Estrógenos/farmacología , Estrógenos/farmacología , Femenino , Humanos , Ligandos , Mifepristona , Promegestona/farmacología , Células Tumorales Cultivadas
9.
J Comp Neurol ; 392(1): 35-47, 1998 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-9482231

RESUMEN

To assess the degree of order exhibited during development by crossed and uncrossed retinocollicular pathways, focal deposits of 1,1'-dioctodecyl-3,3,3'3'-tetramethylinodocarbocyanine perchlorate (DiI) were made into the temporal or nasal retina of prenatal and postnatal ferrets. This procedure revealed that the first retinal fibers (from the ipsilateral temporal retina) grow into the superior colliculus at embryonic (E) day 30. Both crossed and uncrossed fibers innervate the colliculus by E34. At this age, terminal arbors were lacking, and there was no evidence of extensive axonal branching. Retinocollicular arbors first appeared at E38, with both the crossed and uncrossed projections forming well-defined terminal zones that appeared to be localized to topographically appropriate regions. At E38, the ipsilateral terminal zone was significantly larger but notably less dense than the contralateral zone. At this and later ages (postnatal day [P] 0 and P7), a few crossed and uncrossed fibers extended beyond the terminal zone. Four days later, at P0, the terminal zone of the uncrossed projection was reduced in size in comparison with that of earlier ages, whereas the crossed projection became substantially larger. By P7, the few misprojecting fibers seen in younger ferrets had been virtually eliminated. When focal retinal deposits of tracer were made into the nasal retina of E36 and E40 ferrets, crossed fibers were found to innervate the caudal segment of the superior colliculus. These crossed nasal cells appear to project to the topographically appropriate region of the superior colliculus (caudal segment) but on the wrong side of the brain. Collectively, the present findings indicate that throughout development the ferret retinocollicular pathway is characterized by a remarkable degree of topographic precision as evident by the paucity of axonal branches and the low number of grossly misprojecting axons.


Asunto(s)
Hurones/fisiología , Retina/embriología , Colículos Superiores/embriología , Animales , Axones/fisiología , Axones/ultraestructura , Carbocianinas , Femenino , Colorantes Fluorescentes , Inmunohistoquímica , Microscopía Confocal , Embarazo , Retina/citología , Colículos Superiores/citología , Vías Visuales/citología , Vías Visuales/embriología
10.
J Comp Neurol ; 394(3): 335-43, 1998 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-9579397

RESUMEN

At maturity, ON and OFF alpha ganglion cells in the cat retina are arrayed in regular mosaics, with adjacent cells commonly forming ON-OFF pairs. In the present study, we investigated the role of activity-mediated ganglion cell death in the formation of such cellular patterns. Because direct measures of ganglion cell mosaics are problematic in the developing retina, we examined the distributions of ON and OFF alpha cells in the postnatal cat retina by assessing the degree to which cells in closest proximity were of opposite sign (i.e., ON-OFF pairs). Computer simulations demonstrated that superimposition of two regular distributions results in a high incidence (approximately 90%) of opposite sign pairs. This is also the case for ON and OFF alpha cells in the mature retina, reflecting the high degree of regularity exhibited by this cell class. In contrast, during the first postnatal month, alpha cells displayed a much lower incidence of opposite sign pairs (approximately 60%), comparable to the superimposition of two simulated random distributions. We also show that there is a 20% loss of alpha cells in the central retina during postnatal development and that this magnitude of loss is sufficient to form regular distributions of ON and OFF cells. To assess the influence of sodium voltage-gated activity on this developmental process, intraocular injections of tetrodotoxin (TTX) were made during the postnatal period of alpha cell loss. When the TTX-treated animals reached maturity, there was a dose-related decrease in the incidence of opposite sign pairs, without any appreciable change in cell density. Moreover, the regularity index of ON and OFF cells was significantly lower than normal in the TTX-treated retinas. These findings demonstrate that a spatially selective pattern of ganglion cell loss contributes to the formation of regular ON and OFF ganglion cell distributions and that such cell loss is regulated by retinal activity.


Asunto(s)
Gatos/anatomía & histología , Simulación por Computador , Modelos Neurológicos , Células Ganglionares de la Retina/patología , Animales , Recuento de Células , Muerte Celular/fisiología , Retina/citología , Retina/crecimiento & desarrollo , Tetrodotoxina/farmacología
11.
J Comp Neurol ; 368(2): 295-303, 1996 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-8725308

RESUMEN

The topographic organization of the developing retinocollicular pathway was assessed by making focal deposits of a retrograde tracer (usually rhodamine latex beads) into the superficial layers of the superior colliculus of fetal cats at known gestational ages. Subsequently, the distributions of labeled cells in the contralateral and ipsilateral retinas were examined. At all stages of development, a high density of labeled cells was found in a delimited area (core region) of both retinas. The locations of the retinal regions containing the high density of labeled cells varied with the locus of the tracer deposit in the superior colliculus in a manner consistent with the topographic organization of the mature cat's retinocollicular pathway. Additionally, some labeled ganglion cells, considered to be ectopic, were found to be scattered throughout the contralateral and ipsilateral fetal retinas. Such ectopic cells were few in number throughout prenatal development. For every 100 cells projecting to the appropriate region of the colliculus, we estimate that less than one ganglion cell makes a gross projection error. The incidence of ectopic cells did not differ between the contralateral and ipsilateral retina, even though the overall density of crossed labeled cells was always greater than that of uncrossed labeled cells. In the youngest fetal animals, tracer deposits into the caudal portion of the superior colliculus resulted in a core region of labeled cells in the contralateral nasal retina as well as in the nasal ipsilateral retina. Such uncrossed nasal cells, not seen in more mature animals, appear to innervate the appropriate topographic location of the superior colliculus, but on the wrong side of the brain. Most likely, these uncrossed nasal ganglion cells contribute to the widespread distribution of the ipsilateral retinocollicular pathway observed in fetal cats after intraocular injections of anterograde tracers (Williams and Chalupa, 1982). Collectively, our findings demonstrate that the developing retinocollicular pathway of the fetal cat is characterized by a remarkable degree of topographic precision.


Asunto(s)
Feto/anatomía & histología , Vías Nerviosas/anatomía & histología , Retina/anatomía & histología , Células Ganglionares de la Retina/citología , Colículos Superiores/anatomía & histología , Animales , Gatos
12.
J Med Chem ; 42(1): 87-94, 1999 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-9888835

RESUMEN

A new series of hydroxamic acid-based matrix metalloproteinase (MMP) inhibitors containing a unique phosphinamide motif derived from D-amino acid was designed, synthesized, and tested for enzyme inhibition. Compounds with an R configuration at phosphorus were found to be potent MMP inhibitors while molecules with the S configuration were almost inactive. Structure-activity relationship studies of the series led to the discovery of the potent inhibitor 16 with IC50 = 20.5 nM and 24.4 nM against fibroblast collagenase (MMP-1) and stromelysin (MMP-3), respectively. The binding mode of this novel phosphinamide-based series of MMP inhibitors was established based on X-ray crystallography of the complex of stromelysin and 16.


Asunto(s)
Ácidos Hidroxámicos/síntesis química , Metaloendopeptidasas/antagonistas & inhibidores , Compuestos Organofosforados/síntesis química , Inhibidores de Proteasas/síntesis química , Sitios de Unión , Cristalografía por Rayos X , Diseño de Fármacos , Humanos , Ácidos Hidroxámicos/química , Ácidos Hidroxámicos/metabolismo , Ácidos Hidroxámicos/farmacología , Metaloproteinasa 1 de la Matriz , Metaloproteinasa 13 de la Matriz , Metaloproteinasa 3 de la Matriz/metabolismo , Metaloproteinasa 7 de la Matriz , Metaloproteinasa 9 de la Matriz , Inhibidores de la Metaloproteinasa de la Matriz , Modelos Moleculares , Compuestos Organofosforados/química , Compuestos Organofosforados/metabolismo , Compuestos Organofosforados/farmacología , Inhibidores de Proteasas/química , Inhibidores de Proteasas/metabolismo , Inhibidores de Proteasas/farmacología , Proteínas Recombinantes/antagonistas & inhibidores , Estereoisomerismo , Relación Estructura-Actividad
13.
J Med Chem ; 43(3): 369-80, 2000 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-10669564

RESUMEN

A new generation of cyclic matrix metalloproteinase (MMP) inhibitors derived from dl-piperazinecarboxylic acid has been described. The design involves: incorporation of hydroxamic acid as the bidentate chelating agent for catalytic Zn(2+), placement of a sulfonamide group at the 1N-position of the piperazine ring to fill the S1' pocket of the enzyme, and finally attachment of diverse functional groups at the 4N-position to optimize potency and peroral absorption. A unique combination of all three elements produced inhibitor 20 with high affinity for MMPs 1, 3, 9, and 13 (24, 18, 1.9, and 1.3 nM, respectively). X-ray crystallography data obtained for MMP-3 cocrystallized with 20 gave detailed information on key binding interactions defining an overall scaffold geometry for piperazine-based MMP inhibitors.


Asunto(s)
Metaloendopeptidasas/antagonistas & inhibidores , Piperazinas/síntesis química , Inhibidores de Proteasas/síntesis química , Sulfonamidas/síntesis química , Animales , Cartílago/citología , Cartílago/efectos de los fármacos , Bovinos , Células Cultivadas , Cristalografía por Rayos X , Diseño de Fármacos , Modelos Moleculares , Piperazinas/química , Piperazinas/farmacología , Inhibidores de Proteasas/química , Inhibidores de Proteasas/farmacología , Proteínas Recombinantes/antagonistas & inhibidores , Estereoisomerismo , Relación Estructura-Actividad , Sulfonamidas/química , Sulfonamidas/farmacología
14.
Ann N Y Acad Sci ; 878: 40-60, 1999 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-10415719

RESUMEN

Since their inception during the eighties, MMP inhibitors (MMPIs) have gone through several cycles of metamorphosis. The design of early MMPIs was based on the cleavage site of peptide substrates. The second generation contained a substituted succinate scaffold (e.g., marimastat) coupled to a modified amino acid residue. The lower molecular weight analogs with multiple substitution possibilities produced a series of MMP inhibitors with varying degrees of selectivity for various MMPs. The introduction of sulfonamides in the midnineties added a new dimension to this field. The simplicity of synthesis coupled with high potency (e.g., CGS-27023A, AG-3340) produced a number of clinical candidates. This review highlights some of the key features that contributed to the discovery of this novel series of MMP inhibitors.


Asunto(s)
Metaloendopeptidasas/antagonistas & inhibidores , Inhibidores de Proteasas/síntesis química , Caprolactama/síntesis química , Caprolactama/química , Caprolactama/farmacología , Diseño de Fármacos , Matriz Extracelular/enzimología , Metaloendopeptidasas/química , Ácidos Fosfínicos/síntesis química , Ácidos Fosfínicos/química , Ácidos Fosfínicos/farmacología , Piperazinas/síntesis química , Piperazinas/química , Piperazinas/farmacología , Inhibidores de Proteasas/química , Inhibidores de Proteasas/farmacología
15.
Brain Res Dev Brain Res ; 46(2): 303-8, 1989 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-2720962

RESUMEN

We have studied the distribution of callosal projection neurons in area 17 of a fetal rhesus monkey which received large injections of horseradish peroxidase into the contralateral occipital cortex. In comparison to other cortical areas, area 17 contains few callosal projection neurons. Most of these cells are confined to a region extending tangentially about 2.5 mm from the 17/18 border, although a few neurons were noted as much as 5 mm from the border. Comparing the distribution of callosal projection neurons in the fetal monkey with what has been described in newborn and adult macaques, it is apparent that although some degree of refinement in striate callosal connections may occur during in utero development, the prenatal development of callosal connections in the macaque is inherently adult-like.


Asunto(s)
Cuerpo Calloso/embriología , Desarrollo Embrionario y Fetal , Corteza Visual/embriología , Animales , Cuerpo Calloso/citología , Edad Gestacional , Macaca mulatta , Vías Nerviosas/anatomía & histología , Corteza Visual/citología
16.
Clin Chim Acta ; 92(3): 481-9, 1979 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-436288

RESUMEN

A new genetic variant form of glucosephosphate isomerase has been found in a family heterozygous for the mutant allele. The mutant enzyme, unlike other phenotypic variants, does not appear to be the result of a single amino acid replacement. The allozyme exhibits an isoelectric point of 5.7 and is thus much more acidic than the normal enzyme (pI = 9.3). The allozyme has been isolated from placenta and separated from the normal homodimer and heterodimer by isoelectric focusing. The enzyme exhibits normal Km and Ki values for the substrates and competitive inhibitors. The allozyme exhibits a normal pH optimum and thermal stability. However, the molecular specific activity of the variant enzyme as quantitated by radioimmunoassay is significantly lower than normal. Analytical gel filtration revealed that the molecular weight of the weight of the enzyme is significantly lower than the normal enzyme. These data thus suggest that the phenotype is unlike any previously reported and is due to a deletion mutation.


Asunto(s)
Variación Genética , Glucosa-6-Fosfato Isomerasa/genética , Alelos , Estabilidad de Medicamentos , Electroforesis en Gel de Almidón , Eritrocitos/enzimología , Femenino , Glucosa-6-Fosfato Isomerasa/sangre , Heterocigoto , Humanos , Mutación , Placenta/enzimología , Embarazo , Radioinmunoensayo
17.
Steroids ; 40(6): 679-89, 1982 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-7187716

RESUMEN

Several 7 alpha-substituted 4-androstene-3,17-diones are potent inhibitors of the biosynthesis of estrogens, with the most effective being 7 alpha-(4'-amino)phenylthio-4-androstene-3,17-dione. An azide derivative of this 7 alpha-thioether compound has been prepared as a potential photoaffinity inhibitor. The enzyme kinetics of the azide analog were examined under both dark conditions and UV irradiation. In the dark, the azide was a very potent competitive inhibitor, with an apparent Ki of 1.3 nM. Under UV-irradiation, a time-dependent loss of aromatase activity was also observed. These studies indicate that the 7 alpha-substituent enhances the affinity of the steroidal analogs for the enzyme site.


Asunto(s)
Androstenodiona/análogos & derivados , Androstenodiona/síntesis química , Inhibidores de la Aromatasa , Oxidorreductasas/antagonistas & inhibidores , Marcadores de Afinidad , Androstenodiona/farmacología , Aromatasa/efectos de la radiación , Femenino , Humanos , Cinética , Espectrometría de Masas , Microsomas/enzimología , Placenta/enzimología , Embarazo , Relación Estructura-Actividad , Rayos Ultravioleta
18.
Steroids ; 50(1-3): 163-78, 1987.
Artículo en Inglés | MEDLINE | ID: mdl-3504058

RESUMEN

Research efforts over the past several years have focused on the synthesis of competitive and irreversible aromatase inhibitors and examination of these inhibitors in microsomal preparations, in cell culture, and in vivo. Several 7 alpha-substituted androstenediones have demonstrated high affinity for placental aromatase, with apparent Ki's ranging from 1 to 30 nM. Inactivation of aromatase occurred following incubation with alkylating and enzyme-activated irreversible inhibitors. 7 alpha-(4'-Amino)phenylthio-4-androstene-3,17-dione (7 alpha-APTA) exhibits potent inhibitory activity of aromatase in the MCF-7 human mammary carcinoma cell line with an ED50 of approximately 25 nM. The inhibitor did not bind to the estrogen receptor of the cells in vitro nor induce levels of progesterone receptors in intact cells. In vivo studies of 7 alpha-APTA in the DMBA-induced rat mammary carcinoma model resulted in 80% of the tumors responding completely or partially at doses of 25 and 50 mg/kg body wt/day. Thus, these 7 alpha-substituted steroidal aromatase inhibitors are effective medicinal agents and may be useful for the treatment of estrogen-dependent breast cancer.


Asunto(s)
Androstadienos/farmacología , Androstenodiona/farmacología , Inhibidores de la Aromatasa , Animales , Femenino , Humanos , Ratas , Ratas Endogámicas , Células Tumorales Cultivadas/efectos de los fármacos , Células Tumorales Cultivadas/metabolismo
19.
Phytopathology ; 90(4): 354-61, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18944584

RESUMEN

ABSTRACT We examined the ability of snow molds to grow at temperatures from -5 to 30 degrees C and to influence the growth of ice through assays for ice nucleation and antifreeze activities. Isolates of Coprinus psychromorbidus (low temperature basidiomycete variant), Microdochium nivale, Typhula phacorrhiza, T. ishikariensis, T. incarnata, and T. canadensis all grew at -5 degrees C, whereas Sclerotinia borealis and S. homoeocarpa did not grow at temperatures below 4 degrees C. The highest threshold ice nucleation temperature was -7 degrees C. Because snow molds are most damaging to their hosts at temperatures above this, our results imply that the pathogenesis of these fungi is not dependent on ice nucleation activity to cause freeze-wounding of host plants. All snow molds that grew at subzero temperatures also exhibited antifreeze activity in the growth medium and in the soluble and insoluble hyphal fractions, with the exception of M. nivale and one isolate of T. canadensis. The lack of high ice nucleation activity combined with the presence of antifreeze activity in all fungal fractions indicates that snow molds can moderate their environment to inhibit or modify intra- and extracellular ice formation, which helps explain their ability to grow at subzero temperatures under snow cover.

20.
Arch Oral Biol ; 29(11): 911-20, 1984.
Artículo en Inglés | MEDLINE | ID: mdl-6596038

RESUMEN

A culture procedure for rat third molars suitable for nutritional-developmental studies is described. Unerupted third molars from 12-day-old rats were cultured in BGJb media containing 20 per cent rat serum and supplemented with 25 mM HEPES buffer, 25 mg ascorbic acid, 20 mg L-glutamine, 12 mg penicillin G and 10 mg streptomycin sulphate per 100 ml of media. Molars were cultured at the liquid-gas interphase using a 50 per cent O2, 45 per cent N2, 5 per cent CO2 gas mixture at 10 lb-psig (pounds per square inch guage). Molar cultures were maintained successfully for 9-14 days without evidence of necrosis, although they developed at a slower rate than in vivo. Molars cultured in 50 per cent O2 compared to those cultured in 21 per cent O2 for periods of 2, 4, 6 and 8 days had higher values for protein, alkaline phosphatase (AP), Ca, P and Ca/P. Vitamin-A-deficiency gave lower values for AP, Ca, P, Ca/P, 45Ca, 35S and [14C]-proline uptake. Histologically, A - molars had atrophic ameloblasts, some foci of squamous metaplasia and abnormal keratin formation. Thus, deficiency of vitamin A imposed during in-vitro development of rat third molars retarded dentinogenesis and interfered with early mineralization of enamel and dentine.


Asunto(s)
Odontogénesis , Deficiencia de Vitamina A/fisiopatología , Envejecimiento , Animales , Medios de Cultivo , Dentinogénesis , Diente Molar/metabolismo , Diente Molar/patología , Técnicas de Cultivo de Órganos , Consumo de Oxígeno , Ratas , Ratas Endogámicas , Calcificación de Dientes , Deficiencia de Vitamina A/metabolismo , Deficiencia de Vitamina A/patología
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