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1.
Gynecol Oncol Rep ; 36: 100762, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33869715

RESUMEN

•Choriocarcinomas can follow molar, ectopic, or normal pregnancies.•The early diagnosis and treatment of choriocarcinomas is imperative.•Atypical symptoms in pregnancy should raise suspicion for choriocarcinoma.•Choriocarcinoma must always be in the differential in uncomplicated term pregnancies.

2.
BMJ Case Rep ; 14(2)2021 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-33622740

RESUMEN

We report the case of retrograde varicella zoster virus (VZV) reactivation presenting as aseptic meningitis without rash in a generally healthy pregnant patient. A 27-year-old nulliparous woman at 25 weeks of gestation presented to the emergency department with a 1-day history of severe headache associated with nausea, photophobia and neck stiffness. After ruling out a space-occupying lesion by brain imaging, lumbar puncture was performed. Cerebrospinal fluid analysis by PCR revealed the presence of VZV, making the diagnosis of acute varicella meningitis. The patient had immunoglobulin studies consistent with a history of primary VZV infection, thus confirming reactivation of VZV rather than primary infection. The patient was treated with acyclovir for 14 days and recovered fully. Her neonate was delivered full term without any evidence of vertical transmission. This is only the second reported case of VZV meningitis in a pregnant patient in the medical literature, and the first case in the US that was reported.


Asunto(s)
Varicela , Diabetes Mellitus Tipo 1 , Herpes Zóster , Meningitis Viral , Adulto , Femenino , Herpes Zóster/complicaciones , Herpes Zóster/diagnóstico , Herpes Zóster/tratamiento farmacológico , Herpesvirus Humano 3 , Humanos , Recién Nacido , Meningitis Viral/diagnóstico , Meningitis Viral/tratamiento farmacológico , Embarazo , Mujeres Embarazadas
3.
Eur J Med Chem ; 187: 111919, 2020 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-31810783

RESUMEN

Phosphatidylcholine-specific phospholipase C (PC-PLC) is a promising target for new anticancer treatment. Herein, we report our work in the discovery of novel drug-like PC-PLC inhibitors. Virtual screening led to the identification of promising hits from four different structural series that contain the molecular scaffold of benzenesulphonamides (10), pyrido[3,4-b]indoles (22), morpholinobenzoic acid (84) and benzamidobenzoic acid (80). 164 structural analogues were tested to investigate the chemical space around the hit series and to generate preliminary structurally activity relationships (SAR). Two of the pyrido[3,4-b]indoles (22_10 and 22_15) had comparable or better potency as D609, an established but non-drug-like PC-PLC inhibitor. Furthermore, three morpholinobenzoic acids (84, 84_4 and 84_5) had superior potency than D609. Therefore, this study paves the way towards the development of drug-like PL-PLC inhibitors as potential anticancer agents.


Asunto(s)
Amidas/farmacología , Antineoplásicos/farmacología , Ácido Benzoico/farmacología , Descubrimiento de Drogas , Inhibidores Enzimáticos/farmacología , Indoles/farmacología , Fosfolipasas de Tipo C/antagonistas & inhibidores , Amidas/síntesis química , Amidas/química , Antineoplásicos/síntesis química , Antineoplásicos/química , Ácido Benzoico/síntesis química , Ácido Benzoico/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Humanos , Indoles/síntesis química , Indoles/química , Modelos Moleculares , Estructura Molecular , Relación Estructura-Actividad , Fosfolipasas de Tipo C/metabolismo
4.
J Gynecol Obstet Hum Reprod ; : 101665, 2019 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-31811970

RESUMEN

OBJECTIVE: To evaluate risk factors for cervical ectopic pregnancies. METHODS: Retrospective, quasi-experimental case-control study of cervical ectopic pregnancy (CEP) cases from 2000-2013. Two groups were selected as controls, patients with tubal ectopic (TEP) and intrauterine pregnancies (IUP) without a history of TEP, matched by year of pregnancy and randomly sampled in a 1:3 case-control ratio per each study group. RESULTS: 21 cases were identified and 126 controls included, 63 TEP and IUP each. A binary logistic regression model was used to analyze whether statistically significant preceding factors from a bivariate analysis could predict CEP. Compared to patients with IUP, CEP patients had a higher history of elective abortions, D&C and cervical excisional procedures, with a high effect size (>0.7). Compared to patients with TEP, CEP patients had a higher history of D&C and cervical excisional procedures, with a high effect size (>.7). The risk of CEP was significantly higher with a prior history of D&C compared to an IUP (aOR 1.4; 95% CI, 1.1-9.1; p=0.04) and a TEP (aOR 6.1; 95% CI, 1.8-21.2; p=0.04). CONCLUSION: D&C is a strong risk factor for CEP when compared to pregnancies in other locations. These findings confirm previous associations described in case series.

5.
Endocrinology ; 158(6): 1645-1658, 2017 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-28419211

RESUMEN

The α-subunit of the heterotrimeric Gz protein, Gαz, promotes ß-cell death and inhibits ß-cell replication when pancreatic islets are challenged by stressors. Thus, we hypothesized that loss of Gαz protein would preserve functional ß-cell mass in the nonobese diabetic (NOD) model, protecting from overt diabetes. We saw that protection from diabetes was robust and durable up to 35 weeks of age in Gαz knockout mice. By 17 weeks of age, Gαz-null NOD mice had significantly higher diabetes-free survival than wild-type littermates. Islets from these mice had reduced markers of proinflammatory immune cell infiltration on both the histological and transcript levels and secreted more insulin in response to glucose. Further analyses of pancreas sections revealed significantly fewer terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL)-positive ß-cells in Gαz-null islets despite similar immune infiltration in control mice. Islets from Gαz-null mice also exhibited a higher percentage of Ki-67-positive ß-cells, a measure of proliferation, even in the presence of immune infiltration. Finally, ß-cell-specific Gαz-null mice phenocopy whole-body Gαz-null mice in their protection from developing hyperglycemia after streptozotocin administration, supporting a ß-cell-centric role for Gαz in diabetes pathophysiology. We propose that Gαz plays a key role in ß-cell signaling that becomes dysfunctional in the type 1 diabetes setting, accelerating the death of ß-cells, which promotes further accumulation of immune cells in the pancreatic islets, and inhibiting a restorative proliferative response.


Asunto(s)
Diabetes Mellitus Experimental/genética , Diabetes Mellitus Tipo 1/genética , Subunidades alfa de la Proteína de Unión al GTP/genética , Animales , Apoptosis/genética , Glucemia/metabolismo , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patología , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/patología , Femenino , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Ratones Noqueados , Ratones Transgénicos , Estreptozocina
6.
Diabetes ; 66(6): 1572-1585, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-28193789

RESUMEN

Prostaglandin E2 (PGE2) is derived from arachidonic acid, whereas PGE3 is derived from eicosapentaenoic acid (EPA) using the same downstream metabolic enzymes. Little is known about the impact of EPA and PGE3 on ß-cell function, particularly in the diabetic state. In this work, we determined that PGE3 elicits a 10-fold weaker reduction in glucose-stimulated insulin secretion through the EP3 receptor as compared with PGE2 We tested the hypothesis that enriching pancreatic islet cell membranes with EPA, thereby reducing arachidonic acid abundance, would positively impact ß-cell function in the diabetic state. EPA-enriched islets isolated from diabetic BTBR Leptinob/ob mice produced significantly less PGE2 and more PGE3 than controls, correlating with improved glucose-stimulated insulin secretion. NAD(P)H fluorescence lifetime imaging showed that EPA acts downstream and independently of mitochondrial function. EPA treatment also reduced islet interleukin-1ß expression, a proinflammatory cytokine known to stimulate prostaglandin production and EP3 expression. Finally, EPA feeding improved glucose tolerance and ß-cell function in a mouse model of diabetes that incorporates a strong immune phenotype: the NOD mouse. In sum, increasing pancreatic islet EPA abundance improves diabetic ß-cell function through both direct and indirect mechanisms that converge on reduced EP3 signaling.


Asunto(s)
Alprostadil/análogos & derivados , Diabetes Mellitus/metabolismo , Dinoprostona/metabolismo , Ácido Eicosapentaenoico/farmacología , Glucosa/metabolismo , Células Secretoras de Insulina/efectos de los fármacos , Insulina/metabolismo , Subtipo EP3 de Receptores de Prostaglandina E/efectos de los fármacos , Alprostadil/metabolismo , Animales , Ácido Araquidónico/metabolismo , Cromatografía de Gases , Perfilación de la Expresión Génica , Secreción de Insulina , Células Secretoras de Insulina/metabolismo , Interleucina-1beta/farmacología , Islotes Pancreáticos/efectos de los fármacos , Islotes Pancreáticos/metabolismo , Espectrometría de Masas , Ratones , Ratones Endogámicos NOD , Ratones Obesos , Imagen Óptica , Fosfolípidos , Subtipo EP3 de Receptores de Prostaglandina E/metabolismo , Transducción de Señal
7.
Cell Rep ; 16(2): 520-530, 2016 07 12.
Artículo en Inglés | MEDLINE | ID: mdl-27346343

RESUMEN

Protein-restricted (PR), high-carbohydrate diets improve metabolic health in rodents, yet the precise dietary components that are responsible for these effects have not been identified. Furthermore, the applicability of these studies to humans is unclear. Here, we demonstrate in a randomized controlled trial that a moderate PR diet also improves markers of metabolic health in humans. Intriguingly, we find that feeding mice a diet specifically reduced in branched-chain amino acids (BCAAs) is sufficient to improve glucose tolerance and body composition equivalently to a PR diet via metabolically distinct pathways. Our results highlight a critical role for dietary quality at the level of amino acids in the maintenance of metabolic health and suggest that diets specifically reduced in BCAAs, or pharmacological interventions in this pathway, may offer a translatable way to achieve many of the metabolic benefits of a PR diet.


Asunto(s)
Aminoácidos de Cadena Ramificada/metabolismo , Obesidad/dietoterapia , Tejido Adiposo Blanco/patología , Aminoácidos de Cadena Ramificada/administración & dosificación , Animales , Glucemia , Proteínas en la Dieta/administración & dosificación , Factores de Crecimiento de Fibroblastos/metabolismo , Gluconeogénesis , Intolerancia a la Glucosa , Humanos , Células Secretoras de Insulina/metabolismo , Masculino , Ratones Endogámicos C57BL , Persona de Mediana Edad , Obesidad/sangre , Tamaño de los Órganos , Estrés Fisiológico
8.
Mol Endocrinol ; 30(5): 543-56, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-27049466

RESUMEN

A defining characteristic of type 1 diabetes mellitus (T1DM) pathophysiology is pancreatic ß-cell death and dysfunction, resulting in insufficient insulin secretion to properly control blood glucose levels. Treatments that promote ß-cell replication and survival, thus reversing the loss of ß-cell mass, while also preserving ß-cell function, could lead to a real cure for T1DM. The α-subunit of the heterotrimeric Gz protein, Gαz, is a tonic negative regulator of adenylate cyclase and downstream cAMP production. cAMP is one of a few identified signaling molecules that can simultaneously have a positive impact on pancreatic islet ß-cell proliferation, survival, and function. The purpose of our study was to determine whether mice lacking Gαz might be protected, at least partially, from ß-cell loss and dysfunction after streptozotocin treatment. We also aimed to determine whether Gαz might act in concert with an activator of the cAMP-stimulatory glucagon-like peptide 1 receptor, exendin-4 (Ex4). Without Ex4 treatment, Gαz-null mice still developed hyperglycemia, albeit delayed. The same finding held true for wild-type mice treated with Ex4. With Ex4 treatment, Gαz-null mice were protected from developing severe hyperglycemia. Immunohistological studies performed on pancreas sections and in vitro apoptosis, cytotoxicity, and survival assays demonstrated a clear effect of Gαz signaling on pancreatic ß-cell replication and death; ß-cell function was also improved in Gαz-null islets. These data support our hypothesis that a combination of therapies targeting both stimulatory and inhibitory pathways will be more effective than either alone at protecting, preserving, and possibly regenerating ß-cell mass and function in T1DM.


Asunto(s)
Diabetes Mellitus Experimental/metabolismo , Péptido 1 Similar al Glucagón/metabolismo , Células Secretoras de Insulina/metabolismo , Adenilil Ciclasas/metabolismo , Animales , Glucemia/efectos de los fármacos , Glucemia/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Proliferación Celular/fisiología , Diabetes Mellitus Experimental/inducido químicamente , Diabetes Mellitus Tipo 1/inducido químicamente , Diabetes Mellitus Tipo 1/metabolismo , Exenatida , Glucosa/metabolismo , Hiperglucemia/tratamiento farmacológico , Hiperglucemia/metabolismo , Hipoglucemiantes/farmacología , Insulina/metabolismo , Células Secretoras de Insulina/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Páncreas/efectos de los fármacos , Páncreas/metabolismo , Péptidos/metabolismo , Ratas , Transducción de Señal/efectos de los fármacos , Estreptozocina/farmacología , Ponzoñas/metabolismo
9.
Aging Cell ; 15(1): 28-38, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26463117

RESUMEN

Inhibition of the mechanistic target of rapamycin (mTOR) signaling pathway by the FDA-approved drug rapamycin has been shown to promote lifespan and delay age-related diseases in model organisms including mice. Unfortunately, rapamycin has potentially serious side effects in humans, including glucose intolerance and immunosuppression, which may preclude the long-term prophylactic use of rapamycin as a therapy for age-related diseases. While the beneficial effects of rapamycin are largely mediated by the inhibition of mTOR complex 1 (mTORC1), which is acutely sensitive to rapamycin, many of the negative side effects are mediated by the inhibition of a second mTOR-containing complex, mTORC2, which is much less sensitive to rapamycin. We hypothesized that different rapamycin dosing schedules or the use of FDA-approved rapamycin analogs with different pharmacokinetics might expand the therapeutic window of rapamycin by more specifically targeting mTORC1. Here, we identified an intermittent rapamycin dosing schedule with minimal effects on glucose tolerance, and we find that this schedule has a reduced impact on pyruvate tolerance, fasting glucose and insulin levels, beta cell function, and the immune system compared to daily rapamycin treatment. Further, we find that the FDA-approved rapamycin analogs everolimus and temsirolimus efficiently inhibit mTORC1 while having a reduced impact on glucose and pyruvate tolerance. Our results suggest that many of the negative side effects of rapamycin treatment can be mitigated through intermittent dosing or the use of rapamycin analogs.


Asunto(s)
Glucemia/efectos de los fármacos , Homeostasis/efectos de los fármacos , Sistema Inmunológico/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Sirolimus/efectos adversos , Sirolimus/farmacología , Animales , Proliferación Celular/efectos de los fármacos , Intolerancia a la Glucosa/tratamiento farmacológico , Células Secretoras de Insulina/efectos de los fármacos , Ratones Endogámicos C57BL , Sirolimus/administración & dosificación , Sirolimus/análogos & derivados
10.
Islets ; 7(3): e1076607, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26452321

RESUMEN

One complication to comparing ß-cell function among islet preparations, whether from genetically identical or diverse animals or human organ donors, is the number of islets required per assay. Islet numbers can be limiting, meaning that fewer conditions can be tested; other islet measurements must be excluded; or islets must be pooled from multiple animals/donors for each experiment. Furthermore, pooling islets negates the possibility of performing single-islet comparisons. Our aim was to validate a 96-well plate-based single islet insulin secretion assay that would be as robust as previously published methods to quantify glucose-stimulated insulin secretion from mouse and human islets. First, we tested our new assay using mouse islets, showing robust stimulation of insulin secretion 24 or 48 h after islet isolation. Next, we utilized the assay to quantify mouse islet function on an individual islet basis, measurements that would not be possible with the standard pooled islet assay methods. Next, we validated our new assay using human islets obtained from the Integrated Islet Distribution Program (IIDP). Human islets are known to have widely varying insulin secretion capacity, and using our new assay we reveal biologically relevant factors that are significantly correlated with human islet function, whether displayed as maximal insulin secretion response or fold-stimulation of insulin secretion. Overall, our results suggest this new microplate assay will be a useful tool for many laboratories, expert or not in islet techniques, to be able to precisely quantify islet insulin secretion from their models of interest.


Asunto(s)
Bioensayo/métodos , Insulina/metabolismo , Islotes Pancreáticos/metabolismo , Adulto , Animales , Bioensayo/instrumentación , Técnicas de Cultivo de Célula/instrumentación , Femenino , Glucosa/farmacología , Humanos , Secreción de Insulina , Islotes Pancreáticos/citología , Masculino , Ratones , Persona de Mediana Edad , Adulto Joven
11.
Am J Physiol Gastrointest Liver Physiol ; 309(6): G431-42, 2015 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-26185331

RESUMEN

Stimulation of digestive organs by enteric peptides is lost during total parental nutrition (PN). Here we examine the role of the enteric peptide bombesin (BBS) in stimulation of the exocrine and endocrine pancreas during PN. BBS protects against exocrine pancreas atrophy and dysfunction caused by PN. BBS also augments circulating insulin levels, suggesting an endocrine pancreas phenotype. While no significant changes in gross endocrine pancreas morphology were observed, pancreatic islets isolated from BBS-treated PN mice showed a significantly enhanced insulin secretion response to the glucagon-like peptide-1 (GLP-1) agonist exendin-4, correlating with enhanced GLP-1 receptor expression. BBS itself had no effect on islet function, as reflected in low expression of BBS receptors in islet samples. Intestinal BBS receptor expression was enhanced in PN with BBS, and circulating active GLP-1 levels were significantly enhanced in BBS-treated PN mice. We hypothesized that BBS preserved islet function indirectly, through the enteroendocrine cell-pancreas axis. We confirmed the ability of BBS to directly stimulate intestinal enteroid cells to express the GLP-1 precursor preproglucagon. In conclusion, BBS preserves the exocrine and endocrine pancreas functions during PN; however, the endocrine stimulation is likely indirect, through the enteroendocrine cell-pancreas axis.


Asunto(s)
Bombesina/farmacología , Péptido Liberador de Gastrina/análogos & derivados , Islotes Pancreáticos/efectos de los fármacos , Páncreas Exocrino/efectos de los fármacos , Nutrición Parenteral/efectos adversos , Amilasas/metabolismo , Animales , ADN/metabolismo , Alimentos Formulados , Regulación de la Expresión Génica , Hiperglucemia/sangre , Islotes Pancreáticos/anatomía & histología , Lipasa/metabolismo , Masculino , Ratones , Ratones Endogámicos ICR , Páncreas Exocrino/anatomía & histología , Hormonas Pancreáticas/metabolismo
12.
Diabetes ; 64(11): 3798-807, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26153246

RESUMEN

There is growing concern over confounding artifacts associated with ß-cell-specific Cre-recombinase transgenic models, raising questions about their general usefulness in research. The inducible ß-cell-specific transgenic (MIP-CreERT(1Lphi)) mouse was designed to circumvent many of these issues, and we investigated whether this tool effectively addressed concerns of ectopic expression and disruption of glucose metabolism. Recombinase activity was absent from the central nervous system using a reporter line and high-resolution microscopy. Despite increased pancreatic insulin content, MIP-CreERT mice on a chow diet exhibited normal ambient glycemia, glucose tolerance and insulin sensitivity, and appropriate insulin secretion in response to glucose in vivo and in vitro. However, MIP-CreERT mice on different genetic backgrounds were protected from high-fat/ streptozotocin (STZ)-induced hyperglycemia that was accompanied by increased insulin content and islet density. Ectopic human growth hormone (hGH) was highly expressed in MIP-CreERT islets independent of tamoxifen administration. Circulating insulin levels remained similar to wild-type controls, whereas STZ-associated increases in α-cell number and serum glucagon were significantly blunted in MIP-CreERT(1Lphi) mice, possibly due to paracrine effects of hGH-induced serotonin expression. These studies reveal important new insight into the strengths and limitations of the MIP-CreERT mouse line for ß-cell research.


Asunto(s)
Diabetes Mellitus Experimental/metabolismo , Hormona de Crecimiento Humana/metabolismo , Hiperglucemia/metabolismo , Células Secretoras de Insulina/metabolismo , Fenotipo , Animales , Glucemia/metabolismo , Diabetes Mellitus Experimental/genética , Homeostasis/fisiología , Hormona de Crecimiento Humana/genética , Humanos , Hiperglucemia/genética , Insulina/sangre , Masculino , Ratones , Ratones Transgénicos
13.
Mater Sci Eng C Mater Biol Appl ; 40: 407-17, 2014 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-24857509

RESUMEN

Biodegradable magnesium (Mg) alloys have the potential to replace currently used implants for fixation, thereby eliminating the need for removal surgeries. To achieve a controllable degradation rate, surface oxidation has been proposed as an avenue to reduce the initial degradation. This study aims to investigate the oxidation behavior of binary Mg-rare earth alloys and the effect on biodegradation. Cast Mg-3X alloys (X=Gd, Y, Sc) were prepared and then oxidized in pure oxygen. The oxidation rate was evaluated using TGA and the oxides were further investigated and characterized using SEM, AES and XPS. The effect of oxidation on the degradation rate was investigated by immersion testing in Hanks' solution. The thermodynamics and oxidation kinetics of the alloys are discussed in regard to the obtained results, and it was concluded that the experimental results are in agreement with thermodynamic predictions.


Asunto(s)
Aleaciones/química , Gadolinio/química , Magnesio/química , Escandio/química , Itrio/química , Implantes Absorbibles , Corrosión , Ensayo de Materiales , Oxidación-Reducción , Termodinámica
14.
Diabetes ; 62(6): 1904-12, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23349487

RESUMEN

BTBR mice develop severe diabetes in response to genetically induced obesity due to a failure of the ß-cells to compensate for peripheral insulin resistance. In analyzing BTBR islet gene expression patterns, we observed that Pgter3, the gene for the prostaglandin E receptor 3 (EP3), was upregulated with diabetes. The EP3 receptor is stimulated by prostaglandin E2 (PGE2) and couples to G-proteins of the Gi subfamily to decrease intracellular cAMP, blunting glucose-stimulated insulin secretion (GSIS). Also upregulated were several genes involved in the synthesis of PGE2. We hypothesized that increased signaling through EP3 might be coincident with the development of diabetes and contribute to ß-cell dysfunction. We confirmed that the PGE2-to-EP3 signaling pathway was active in islets from confirmed diabetic BTBR mice and human cadaveric donors, with increased EP3 expression, PGE2 production, and function of EP3 agonists and antagonists to modulate cAMP production and GSIS. We also analyzed the impact of EP3 receptor activation on signaling through the glucagon-like peptide (GLP)-1 receptor. We demonstrated that EP3 agonists antagonize GLP-1 signaling, decreasing the maximal effect that GLP-1 can elicit on cAMP production and GSIS. Taken together, our results identify EP3 as a new therapeutic target for ß-cell dysfunction in T2D.


Asunto(s)
Glucosa/farmacología , Insulina/metabolismo , Islotes Pancreáticos/efectos de los fármacos , Islotes Pancreáticos/metabolismo , Subtipo EP3 de Receptores de Prostaglandina E/metabolismo , Animales , Dinoprostona/metabolismo , Femenino , Receptor del Péptido 1 Similar al Glucagón , Humanos , Técnicas In Vitro , Secreción de Insulina , Células Secretoras de Insulina/efectos de los fármacos , Células Secretoras de Insulina/metabolismo , Ratones , Receptores de Glucagón/genética , Receptores de Glucagón/metabolismo , Subtipo EP3 de Receptores de Prostaglandina E/agonistas , Subtipo EP3 de Receptores de Prostaglandina E/antagonistas & inhibidores
15.
Acta Biomater ; 9(2): 5331-40, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22902815

RESUMEN

Magnesium and its alloys have been investigated for their potential application as biodegradable implant materials. Although properties of magnesium such as biocompatibility and susceptibility to dissolution are desirable for biodegradable implant applications, its high degradation rate and low strength pose a significant challenge. A potential way to reduce the initial degradation rate is to form a self-passivating protective layer on the surface of the alloy. Oxides with a low enthalpy of formation result in a strong thermodynamic driving force to produce oxide surfaces that are more stable than the native oxide (MgO), and possibly reduce the initial degradation rate in these alloys. In the present study a ternary Mg-3wt.% Sc-3wt.% Y alloy was investigated and its oxidation behavior studied. The effect of surface passivation on the in vitro degradation rate was studied and the degradation products identified. The results show that the oxide provided an initial degradation barrier and 24h oxidation resulted in a negligible degradation rate for up to 23 days. Furthermore, the degradation products of the alloy showed no significant toxicity to osteoblastic cells, and cell proliferation studies confirmed cell attachment and proliferation on the surface of the oxidized alloy.


Asunto(s)
Implantes Absorbibles , Aleaciones/farmacología , Animales , Muerte Celular/efectos de los fármacos , Forma de la Célula/efectos de los fármacos , Ratones , Microscopía Electrónica de Rastreo , Osteoblastos/citología , Osteoblastos/efectos de los fármacos , Osteoblastos/ultraestructura , Oxidación-Reducción/efectos de los fármacos , Espectroscopía de Fotoelectrones , Termodinámica , Factores de Tiempo , Difracción de Rayos X
16.
J Biomed Mater Res B Appl Biomater ; 100(6): 1524-34, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22689410

RESUMEN

Magnesium has recently received an increased amount of interest due to its potential use in biodegradable implant applications. The rapid degradation of conventional Mg is, however, a major limitation that needs to be addressed in the design of these materials, along with consideration of toxicity in selection of alloying elements. In this study, five alloys in the Mg-xCa-ySr system (x = 0.5-7.0 wt %; y = 0.5-3.5 wt %) were prepared and characterized for their suitability as degradable orthopedic implant materials. The alloys were characterized using optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, degradation measurements in Hanks' solution at 37°C, compression testing, and in vitro cytotoxicity testing with a mouse osteoblastic cell line. The results indicate that the Mg-1.0Ca-0.5Sr alloy is the most promising alloy for orthopedic implant applications since it showed the lowest degradation rate in Hanks' solution (0.01 mL cm(-2) h(-1)) along with no significant toxicity to MC3T3-E1 osteoblasts and a compressive strength of 274 ± 4 MPa.


Asunto(s)
Implantes Absorbibles , Aleaciones , Calcio , Magnesio , Ensayo de Materiales , Osteoblastos/metabolismo , Estroncio , Animales , Línea Celular , Humanos , Ratones , Osteoblastos/citología
17.
J Biol Chem ; 287(24): 20344-55, 2012 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-22457354

RESUMEN

Insufficient plasma insulin levels caused by deficits in both pancreatic ß-cell function and mass contribute to the pathogenesis of type 2 diabetes. This loss of insulin-producing capacity is termed ß-cell decompensation. Our work is focused on defining the role(s) of guanine nucleotide-binding protein (G protein) signaling pathways in regulating ß-cell decompensation. We have previously demonstrated that the α-subunit of the heterotrimeric G(z) protein, Gα(z), impairs insulin secretion by suppressing production of cAMP. Pancreatic islets from Gα(z)-null mice also exhibit constitutively increased cAMP production and augmented glucose-stimulated insulin secretion, suggesting that Gα(z) is a tonic inhibitor of adenylate cyclase, the enzyme responsible for the conversion of ATP to cAMP. In the present study, we show that mice genetically deficient for Gα(z) are protected from developing glucose intolerance when fed a high fat (45 kcal%) diet. In these mice, a robust increase in ß-cell proliferation is correlated with significantly increased ß-cell mass. Further, an endogenous Gα(z) signaling pathway, through circulating prostaglandin E activating the EP3 isoform of the E prostanoid receptor, appears to be up-regulated in insulin-resistant, glucose-intolerant mice. These results, along with those of our previous work, link signaling through Gα(z) to both major aspects of ß-cell decompensation: insufficient ß-cell function and mass.


Asunto(s)
Subunidades alfa de la Proteína de Unión al GTP/metabolismo , Intolerancia a la Glucosa/metabolismo , Células Secretoras de Insulina/metabolismo , Adenosina Trifosfato/genética , Adenosina Trifosfato/metabolismo , Adenilil Ciclasas/genética , Adenilil Ciclasas/metabolismo , Animales , Proliferación Celular/efectos de los fármacos , Tamaño de la Célula , AMP Cíclico/genética , AMP Cíclico/metabolismo , Grasas de la Dieta/efectos adversos , Grasas de la Dieta/farmacología , Subunidades alfa de la Proteína de Unión al GTP/genética , Eliminación de Gen , Intolerancia a la Glucosa/inducido químicamente , Intolerancia a la Glucosa/genética , Intolerancia a la Glucosa/patología , Insulina/genética , Insulina/metabolismo , Secreción de Insulina , Células Secretoras de Insulina/patología , Ratones , Ratones Mutantes , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética
18.
J Mech Behav Biomed Mater ; 7: 87-95, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22340688

RESUMEN

Magnesium (Mg) has garnered significant interest for its potential use as a biodegradable implant material. Of specific interest in this study is the effect of zinc (Zn) and strontium (Sr) additions on both the mechanical and degradation behaviors in Mg due to their established beneficial effect on strength and microstructural grain refinement while being biocompatible. Three binary Mg-x wt% Sr (x=0.5, 1.0, 1.5) alloys and three ternary Mg-x wt%Zn-0.5 wt% Sr (x=2.0, 4.0, 6.0) were studied to evaluate their mechanical and degradation behavior. Mechanical testing was performed at room temperature on solution-treated and peak aged alloys using microhardness and tensile tests. Degradation was studied using immersion tests in Hanks' solution. Results indicate a decrease in grain size and an increase in strength with increasing Sr and Zn content. When considering degradation behavior Mg-0.5 wt%Sr demonstrated the lowest degradation rate among binary alloys. At constant Sr content at 0.5 wt%, the addition of Zn increased the corrosion rate, with the highest rate for the Mg-6.0 wt%Zn-0.5 wt%Sr. The alloys which best optimized both mechanical and degradation behaviors were Mg-2.0 wt%Zn-0.5 wt%Sr and Mg-4.0 wt%Zn-0.5 wt%Sr. Finally, microstructure and property relationships were evaluated and discussed in reference to each alloy's potential use as a biodegradable implant material.


Asunto(s)
Implantes Absorbibles , Aleaciones/química , Materiales Biocompatibles/química , Magnesio/química , Corrosión , Ensayo de Materiales , Estroncio/química , Zinc/química
19.
JSLS ; 11(1): 54-8, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17663093

RESUMEN

BACKGROUND: The reported advantages of the laparoscopic approach to appendectomy are shortened hospital stay, less postoperative pain, and earlier return to usual activities (work). However, a prospective, randomized, double-blind trial comparing laparoscopic appendectomy with open appendectomy in active-duty males failed to disclose a benefit of laparoscopic appendectomy with regards to postoperative pain and return to work. The aim of our study was to compare open and laparoscopic appendectomy in overweight patients. METHODS: We conducted a prospective, randomized, double-blind study to determine whether laparoscopic appendectomy or the open procedure in overweight patients offers a significant reduction in lost workdays, postoperative pain, or operative time from. Open appendectomy in overweight patients (those with a body mass index > or =25) may be more difficult due to excessive subcutaneous adipose tissue. The open incision may be of considerable size, which may result in increased postoperative pain and a prolonged convalescence. RESULTS: There was a statistically significant increase in operative time for laparoscopic appendectomy of 11 minutes. As expected, the aggregate incision length for open appendectomy was twice that of the laparoscopic appendectomy. CONCLUSION: The data from this prospective, randomized, double-blind study failed to demonstrate any significant reduction in lost workdays, postoperative pain, or operative time with laparoscopic appendectomy.


Asunto(s)
Apendicectomía , Laparoscopía , Sobrepeso , Adulto , Apendicitis/patología , Apendicitis/cirugía , Índice de Masa Corporal , Método Doble Ciego , Femenino , Humanos , Masculino , Dolor Postoperatorio
20.
Am Surg ; 73(7): 722-4, 2007 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-17674950

RESUMEN

Incisional hernias occur in up to 11 per cent of patients undergoing abdominal surgery. Up to 50 per cent of these patients with hernias will require repeat operative procedures. Management of these hernias have focused primarily on tensile strength of the mesh material, have not addressed currently used materials, and have not compared the strength of these repairs with each other. Forty-nine adult Sprague-Dawley rats had an incisional hernia created by removing a portion of their abdominal wall that was then repaired primarily, using either a composite mesh, Dual mesh (Gore-Tex), or polypropylene mesh. Six weeks after the repair, the rats were euthanized. Hydrostatic distension of the abdominal cavity was performed to compare bursting strength of each repair. Wound tensile strength was assessed and compared. Tissue samples were also taken to compare repair types for incorporation of prosthetic materials. The gross weight of the animals subjected to hydrostatic distention was equivalent between groups, as was the volume required prior to failure of the repair. There was a trend toward improved tensile strength of the Prolene mesh repair, which had a lower average inflammatory and fibrosis score on histology. Overall, the type of mesh used for repair does not seem to impact significantly the strength of the repair when assessed 6 weeks postoperatively. Choice of prosthetic material to repair the hernia should be made based on economics and handling characteristics alone. Prolene mesh has satisfactory strength with the least amount of inflammation and fibrosis.


Asunto(s)
Hernia Abdominal/fisiopatología , Hernia Abdominal/cirugía , Mallas Quirúrgicas , Animales , Humanos , Masculino , Presión , Ratas , Ratas Sprague-Dawley , Resistencia a la Tracción
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