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1.
RFO UPF ; 28(1): 115-131, 20230808.
Article in Portuguese | LILACS, BBO - Dentistry | ID: biblio-1509418

ABSTRACT

Objetivos: Instruir e orientar ao cirurgião dentista e demais profissionais de saúde a importância da detecção e rastreio precoce de lesões pré-malignas. Revisão de Literatura: O Líquen Plano Oral é uma condição dermatológica crônica, de origem auto-imune, relativamente comum na população, que atinge o epitélio de mucosa e pele, sendo considerada, pela Organização Mundial de Saúde (OMS), uma desordem potencialmente maligna quando associado a áreas de ulceração. A revisão de literatura foi realizada nas bases de dados PubMed e Lilacs. Buscamos investigar o potencial de malignização do Líquen Plano Oral associado a condições erosivas, analisando o processo de carcinogênese no processo inflamatório. Conclusão: Conclui-se que o objeto de estudo ainda é um assunto pouco explorado pela literatura, porém há indícios etiopatológicos que enfatizam o processo de malignização oriundo de uma lesão pré-maligna como o Líquen Plano Oral. Além disso, enfatizamos a importância do diagnóstico precoce das lesões estomatognáticas, para que assim possamos aumentar as chances de cura do paciente.(AU)


Objectives: To instruct and guide dentists and other health professionals on the importance of early detection and screening of pre-malignant lesions. Literature Review: Oral Lichen Planus is a chronic dermatological condition, of autoimmune origin, relatively common in the population, which affects the epithelium of the mucosa and skin, being considered, by the World Health Organization (WHO), a potentially fatal disorder. malignant when associated with areas of ulceration. A literature review was performed on the PubMed and Lilacs databases. We sought to investigate the potential for malignancy of Oral Lichen Planus associated with erosive conditions, analyzing the process of carcinogenesis in the inflammatory process. Conclusion: It is concluded that the object of study is still a subject little explored in the literature, but there are etiopathological accusations that emphasize the process of malignancy arising from a pre-malignant lesion such as Oral Lichen Planus. In addition, we emphasize the importance of early diagnosis of stomatognathic lesions, so that we can increase the patient's chances of cure.(AU)


Subject(s)
Humans , Mouth Neoplasms/pathology , Carcinoma, Squamous Cell/pathology , Cell Transformation, Neoplastic/pathology , Lichen Planus, Oral/pathology , Mouth Neoplasms/diagnosis , Carcinoma, Squamous Cell/diagnosis , Lichen Planus, Oral/diagnosis , Early Detection of Cancer
4.
J Gastrointest Surg ; 25(9): 2377-2386, 2021 09.
Article in English | MEDLINE | ID: mdl-33443688

ABSTRACT

BACKGROUND: Ileal pouch-anal anastomosis (IPAA) is a common surgical treatment for ulcerative colitis. Afferent limb stenosis is an infrequent complication following IPAA, suggesting underlying Crohn's disease (CD). We hypothesized that CD-related single nucleotide polymorphisms (SNPs) are associated with afferent limb stenosis. METHODS: Afferent limb stenosis and CD control group patients were recruited from a prospective institutional inflammatory bowel disease database and associated biobank. Patient demographics, Montreal classification, and medication use were recorded. Ten SNPs associated with stricturing Crohn's disease were examined in genomic DNA and compared among afferent limb stenosis, stricturing CD, and non-stricturing CD controls. RESULTS: Twenty-seven afferent limb stenosis and 162 CD control group patients (108 stricturing, 54 non-stricturing) were identified. Patients were gender and race matched. Afferent limb stenosis and stricturing CD controls were younger at diagnosis (Montreal A1/A2 vs. A3) compared to non-stricturing CD controls (both p < 0.05). The majority of afferent limb stenosis patients were non-smokers compared to CD controls (74% vs. 36%, p < 0.01) and did not use biologic therapies (4% vs. 37%, p < 0.001). The FUT2 G allele was more frequent in afferent limb stenosis and stricturing CD controls compared to non-stricturing CD controls (both p < 0.05). The NOD2 T allele was more frequent in stricturing CD controls compared to afferent limb stenosis and non-stricturing CD controls (both p < 0.05). CONCLUSION: Afferent limb stenosis patients are phenotypically similar to stricturing CD controls, but differ with lower smoking rates and lower NOD2 allele frequency. Such differences could contribute to the presentation delay with a stricturing phenotype. Selective SNP assessment may help categorize patients likely to develop afferent limb stenosis.


Subject(s)
Colitis, Ulcerative , Colonic Pouches , Crohn Disease , Colitis, Ulcerative/genetics , Colitis, Ulcerative/surgery , Constriction, Pathologic/genetics , Crohn Disease/genetics , Humans , Polymorphism, Single Nucleotide , Prospective Studies
6.
Dis Colon Rectum ; 63(8): 1090-1101, 2020 08.
Article in English | MEDLINE | ID: mdl-32015287

ABSTRACT

BACKGROUND: Opioid use has grown exponentially over the last decade. The effect of preoperative opioid prescription in patients with Crohn's disease undergoing surgery is unknown. OBJECTIVE: The purpose of this study was to identify whether preoperative opioid prescription is associated with adverse postoperative outcomes in Crohn's disease. DESIGN: This is a single-institution retrospective observational study. SETTINGS: This study was performed at an academic tertiary care center. Details of preoperative opioid prescription were collected from the Kentucky All-Schedule Prescription Electronic Reporting database and the electronic databases of bordering states. PATIENTS: Consecutive patients undergoing ileocolic resection for Crohn's disease from 2014 to 2018 were included. MAIN OUTCOME MEASURES: The outcomes examined were major complications (Clavien-Dindo ≥3a), length of stay, and 30-day hospital readmission. RESULTS: Fifty one of 118 patients were prescribed opioids within 6 months preoperatively (range, 0-33,760 morphine milligram equivalents). Patients with preoperative opioid prescription compared with no preoperative opioid prescription required more daily opioids during hospital admission (p = 0.024). Nineteen patients had a major postoperative complication (preoperative opioid prescription: 26% (13/51) vs no preoperative opioid prescription: 9% (6/67)). On multivariable analysis, preoperative opioid prescription (OR = 2.994 (95% CI, 1.024-8.751); p = 0.045) was a significant risk factor for a major complication. Preoperative opioid prescription was associated with increased length of stay (p < 0.001) and was a risk factor for readmission (OR = 2.978 (95% CI, 1.075-8.246); p = 0.036). Twenty-four patients were readmitted. Using a cutoff for higher opioid prescription of 300 morphine milligram equivalents within 6 months preoperation (eg, 60 tablets of hydrocodone/acetaminophen 5/325), preoperative opioid prescription remained a risk factor for major postoperative complications (OR = 3.148 (95% CI, 1.110-8.928); p = 0.031). LIMITATIONS: This was a retrospective study and could not assess nonprescribed opioid use. CONCLUSIONS: Preoperative opioid prescription was a significant risk factor for adverse outcomes in patients with Crohn's disease undergoing elective ileocolic resection. See Video Abstract at http://links.lww.com/DCR/B113. LA PRESCRIPCIÓN PREOPERATORIA DE OPIOIDES SE ASOCIA CON COMPLICACIONES MAYORES EN PACIENTES CON ENFERMEDAD DE CROHN SOMETIDOS A RESECCIÓN ILEOCÓLICA ELECTIVA: El uso de opioides ha crecido exponencialmente en la última década. Se desconoce el efecto de la prescripción preoperatoria de opioides en pacientes con enfermedad de Crohn sometidos a cirugía.Identificar si la prescripción preoperatoria de opioides está asociada con resultados postoperatorios adversos en la enfermedad de Crohn.Este es un estudio observacional retrospectivo de una sola institución.Este estudio se realizó en un centro académico de atención terciaria. Los detalles de la prescripción preoperatoria de opiáceos se recopilaron de la base de datos de "Kentucky All-Schedule Prescription Electronic Reporting" y de las bases de datos electrónicas de los estados fronterizos.Pacientes consecutivos sometidos a resección ileocólica por enfermedad de Crohn entre 2014-2018.Los resultados examinados fueron complicaciones mayores (Clavien-Dindo ≥3a), duración de la estancia y el reingreso hospitalario de 30 días.A cincuenta y uno de 118 pacientes se le recetaron opioides dentro de los 6 meses preoperatorios (rango, 0 a 33,760 equivalentes de miligramos de morfina). Los pacientes con prescripción preoperatoria de opioides en comparación con ninguna prescripción preoperatoria de opioides requirieron más opioides diarios durante el ingreso hospitalario (p = 0,024). Diecinueve pacientes tuvieron una complicación postoperatoria importante (prescripción preoperatoria de opioides: 26% [13/51] frente a ninguna prescripción preoperatoria de opioides: 9% [6/67]). En el análisis multivariable, la prescripción de opioides preoperatorios (OR = 2.994, IC 95%: 1.024-8.751, p = 0.045) fueron factores de riesgo significativos para una complicación mayor. La prescripción preoperatoria de opioides se asoció con un aumento de la duración de la estadía (p <0.001) y fue un factor de riesgo para el reingreso (OR = 2.978, IC 95%: 1.075-8.246, p = 0.036). Veinticuatro pacientes fueron readmitidos. Utilizando un límite para una mayor prescripción de opioides de 300 miligramos equivalentes de morfina dentro de los 6 meses previos a la operación (p. Ej., 60 tabletas de hidrocodona / acetaminofén 5/325), la prescripción preoperatoria de opioides siguió siendo un factor de riesgo para complicaciones postoperatorias mayores (OR = 3.148 IC 95%: 1.110-8.928, p = 0.031).Este fue un estudio retrospectivo y no pudo evaluar el uso de opioides no prescritos.La prescripción preoperatoria de opioides fue un factor de riesgo significativo para los resultados adversos en pacientes con enfermedad de Crohn sometidos a resección ileocólica electiva. Consulte Video Resumen en http://links.lww.com/DCR/B113.


Subject(s)
Analgesics, Opioid/adverse effects , Crohn Disease/surgery , Elective Surgical Procedures/methods , Preoperative Care/methods , Adult , Analgesics, Opioid/therapeutic use , Case-Control Studies , Crohn Disease/drug therapy , Female , Humans , Intestines/surgery , Length of Stay/statistics & numerical data , Male , Middle Aged , Opioid-Related Disorders/mortality , Patient Readmission/statistics & numerical data , Postoperative Complications/epidemiology , Prescriptions/statistics & numerical data , Retrospective Studies , Risk Factors , Tertiary Care Centers
7.
Biochim Biophys Acta Biomembr ; 1862(5): 183196, 2020 05 01.
Article in English | MEDLINE | ID: mdl-31958437

ABSTRACT

Lipid bilayers form the basis of cell membranes and the phase behaviour of the membrane has been linked to proper cell function. Model membranes composed of relatively simple mixtures of phospholipids and cholesterol can already exhibit complex phase behaviour. Specifically, liquid ordered-liquid disordered fluid phase coexistence occurs in mixtures which contain one saturated long chain phospholipid and one unsaturated long chain phospholipid and cholesterol. This fluid-fluid two phase region persists over a broad range of temperatures and sample compositions and can be observed experimentally in various sample preparations including multilamellar dispersions, bicelles, and multi-lamellae stacked on glass slides. In order to explore the practicality of using oriented samples with different concentrations of the peptide, we investigated the effect of the addition of a synthetic 22 residue amphiphilic peptide on the orientability and phase behaviour of the lipid mixtures, as well as the orientation and dynamics of the peptide itself via 2H NMR. Increasing the peptide concentration promoted the formation of the liquid ordered phase, suggesting a preferential interaction of the peptide with the thicker ordered phase. However, higher peptide content (> 4 mol%) had a significant negative effect on the alignment of bicelles with their bilayer normal perpendicular to the external magnetic field. In the stacked bilayer samples, 6 mol% peptide eliminated the two phase coexistence region altogether and a single liquid ordered phase was observed from 285 to 311 K. Even so, 2H spectra of the peptide itself did not reveal any preference for the peptide to partition into either the liquid disordered or liquid ordered phase and we found two populations of the peptide, one which undergoes rapid axial reorientation about the bilayer normal and a second (powder component) which does not.


Subject(s)
Cholesterol/chemistry , Lipid Bilayers/chemistry , Phospholipids/chemistry , Cell Membrane/metabolism , Cholesterol/metabolism , Lipid Bilayers/metabolism , Magnetic Resonance Spectroscopy/methods , Membranes/metabolism , Orientation, Spatial , Peptides/chemistry , Phosphatidylcholines/chemistry , Phospholipids/metabolism , Surface-Active Agents/chemistry , Temperature
8.
Int J Cancer ; 142(12): 2501-2511, 2018 06 15.
Article in English | MEDLINE | ID: mdl-29388209

ABSTRACT

Colorectal cancer (CRC) is associated with significant morbidity and mortality as many patients are diagnosed with advanced stage disease. MicroRNAs are small, noncoding RNA molecules that have a major role in gene expression regulation and are dysregulated in CRC. The miR-200 family is involved in epithelial-mesenchymal transition (EMT). This systematic review describes the roles of the miR-200 family in EMT in CRC. A search of electronic databases (PubMed and Embase) was conducted between January 2000 and July 2017. Both in vitro and human studies reporting on the miR-200 family and CRC were included. Studies describing molecular pathways and the role of the miR-200 family in the diagnostic and therapeutic management of CRC were analyzed. Thirty-four studies (22 in vitro and 18 human studies) were included. miR-200 family expression is regulated epigenetically and via transcriptional factor regulation. In vitro studies show that transfection of miR-200 family members into chemo-resistant colon cancer cell lines results in improved chemo-sensitivity and epithelial phenotype restoration. There is intra-tumoral variability in the tissue expression of miR-200 family members with decreased expression at the invasive front. Clinical studies in CRC patients have shown decreased primary tumor tissue expression of miR-429, miR-200a and miR-200c may be associated with worse survival. Conversely, increased blood levels of miR-141, miR-200a and miR-200c may be associated with worse outcomes. The miR-200 family has a central role in EMT. The miR200 family has potential for both prognostic and therapeutic management of CRC.


Subject(s)
Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Epithelial-Mesenchymal Transition/genetics , MicroRNAs/genetics , Humans
9.
Langmuir ; 33(8): 1881-1890, 2017 02 28.
Article in English | MEDLINE | ID: mdl-28165749

ABSTRACT

Model membranes composed of two types of long chain phospholipids, one unsaturated and one saturated, along with cholesterol can exhibit two coexisting fluid phases (liquid disordered ([Formula: see text]) and liquid ordered ([Formula: see text])) at various temperatures and compositions. Here we used 1D and 2D 2H NMR to compare the behavior of multilamellar dispersions, magnetically oriented bicelles, and mechanically aligned bilayers on glass plates, all of which contain the same proportions of dipalmitoleoylphosphatidylcholine (DPoPC), dimyristoylphosphatidylcholine (DMPC), and cholesterol. We found that multilamellar dispersions and bilayers aligned on glass plates behave very similarly. These samples were close to a critical composition and exhibit exchange of the lipids between the two fluid phases at temperatures near the [Formula: see text] to [Formula: see text]-[Formula: see text] phase boundary. On the other hand, when a short chain lipid is added to the ternary long chain lipid/cholesterol mixture to form bicelles, the phase behavior is changed significantly and the [Formula: see text] phase occurs at a higher than expected temperature. In addition, there was no evidence of exchange of lipids between the [Formula: see text] and [Formula: see text] phases or critical fluctuations at the temperature where the bulk of the sample enters the two-phase region for these bicelles. It appears that the addition of the short chain lipid results in these samples no longer being near a critical composition.


Subject(s)
Cholesterol/chemistry , Magnetic Resonance Spectroscopy/methods , Dimyristoylphosphatidylcholine/chemistry , Lipids/chemistry , Phosphatidylcholines/chemistry
10.
Biochim Biophys Acta ; 1858(4): 619-26, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26706097

ABSTRACT

Magnetically orienting bicelles are often made by combining the long chain phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) with the short chain phospholipid 1,2-dicaproyl-sn-glycero-3-phosphocholine (DCPC) in buffer. These bicelles orient with their bilayer normals perpendicular to the external magnetic field. We have examined the phase behaviour of DMPC/DCPC bicelles and the effects of cholesterol and the unsaturated phospholipid 1,2-dipalmitoleoyl-sn-glycero-3-phosphocholine (DPoPC) as a function of temperature using static solid state (2)H nuclear magnetic resonance spectroscopy. As expected, cholesterol has an ordering effect on the long phospholipid chains and this is reflected in the phase behaviour of the bicelle mixtures. Liquid disordered-liquid ordered, fluid-fluid phase coexistence is observed in DMPC/cholesterol/DCPC bicelles with cholesterol mole fractions of 0.13 and higher. DPoPC/DMPC/cholesterol/DCPC bicelles also exhibit two fluid phase coexistence over a broad range of temperatures and compositions. Bicelles can provide a useful medium in which to study membrane bound peptides and proteins. The orientation parallel to the magnetic field is favourable for studying membrane peptides/proteins because information about the orientation of relevant molecular bonds or internuclear vectors can be obtained directly from the resulting (2)H spectra. Lanthanide ions can be used to flip the bicelles to have their bilayer normals parallel to the external magnetic field. Yb(3+) was used to flip the DPoPC/DMPC/cholesterol/DCPC bicelles while Eu(3+) was found to be ineffective at flipping bicelles containing cholesterol in the present work.


Subject(s)
Chlorobenzenes/chemistry , Cholesterol/chemistry , Dimyristoylphosphatidylcholine/chemistry , Phospholipids/chemistry , Cholesterol/metabolism , Dimyristoylphosphatidylcholine/metabolism , Lipid Bilayers/chemistry , Magnetic Resonance Spectroscopy , Micelles , Phosphatidylcholines/chemistry , Phosphatidylcholines/metabolism , Temperature
11.
Am J Clin Pathol ; 142(4): 452-8, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25239411

ABSTRACT

OBJECTIVES: Intratumoral CD8+ lymphocytes (IT-CD8s) have shown promise as a prognostic indicator for Merkel cell carcinoma (MCC). We tested whether IT-CD8s predict survival among a population-based MCC cohort. METHODS: One hundred thirty-seven MCC cases that had not previously been analyzed for IT-CD8s were studied. RESULTS: Three-year MCC-specific survival rates were 56%, 72%, and 100% for patients with absent (n = 46), low (n = 85), and moderate or strong (n = 6) IT-CD8s, respectively. Increased IT-CD8s were associated with improved MCC-specific survival in a multivariate competing risk-regression analysis including stage, age, and sex (hazard ratio [HR] = 0.5; 95% confidence interval [CI] = 0.3-0.9). Although a similar trend was observed for overall survival, statistical significance was not reached (HR = 0.8; 95% CI = 0.6-1.0), likely because of the high rate of non-MCC deaths among older patients. CONCLUSIONS: This study of prospectively captured MCC cases supports the concept that cellular immunity is important in MCC outcome and that CD8+ lymphocyte infiltration adds prognostic information to conventional staging.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , Carcinoma, Merkel Cell/immunology , Carcinoma, Merkel Cell/pathology , Skin Neoplasms/mortality , Skin Neoplasms/pathology , Adult , Aged , Aged, 80 and over , Carcinoma, Merkel Cell/mortality , Cohort Studies , Female , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Multivariate Analysis , Neoplasm Staging , Prognosis , Proportional Hazards Models , Prospective Studies , Skin Neoplasms/immunology , Survival Rate
12.
Biophys J ; 106(9): 1970-8, 2014 May 06.
Article in English | MEDLINE | ID: mdl-24806929

ABSTRACT

Static (2)H NMR spectroscopy is used to study the critical behavior of mixtures of 1,2-dioleoyl-phosphatidylcholine/1,2-dipalmitoyl-phosphatidylcholine (DPPC)/cholesterol in molar proportion 37.5:37.5:25 using either chain perdeuterated DPPC-d62 or chain methyl deuterated DPPC-d6. The temperature dependence of the first moment of the (2)H spectrum of the sample made with DPPC-d62 and of the quadrupolar splittings of the chain-methyl-labeled DPPC-d6 sample are directly related to the temperature dependence of the critical order parameter η, which scales as [Formula: see text] near the critical temperature. Analysis of the data reveals that for the chain perdeuterated sample, the value of Tc is 301.51 ± 0.1 K, and that of the critical exponent, ßc = 0.391 ± 0.02. The line shape analysis of the methyl labeled (d6) sample gives Tc = 303.74 ± 0.07 K and ßc = 0.338 ± 0.009. These values obtained for ßc are in good agreement with the predictions of a three-dimensional Ising model. The difference in critical temperature between the two samples having nominally the same molar composition arises because of the lowering of the phase transition temperature that occurs due to the perdeuteration of the DPPC.


Subject(s)
1,2-Dipalmitoylphosphatidylcholine/chemistry , Cholesterol/chemistry , Phosphatidylcholines/chemistry , Temperature , Magnetic Resonance Spectroscopy
13.
Am J Clin Pathol ; 140(6): 838-44, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24225752

ABSTRACT

OBJECTIVES: To determine the clinical utility of p63 expression, which has been identified in several cohorts as a predictor of poorer prognosis in Merkel cell carcinoma (MCC). METHODS: Immunohistochemistry was used to determine p63 expression on MCC tumors from 128 patients. RESULTS: Of the patients, 33% had detectable p63 expression. p63 Positivity was associated with an increased risk of death from MCC (hazard ratio, 2.05; P = .02) in a multivariate Cox regression model considering stage at presentation, age at diagnosis, and sex. Although p63 expression correlated with diminished survival in this largest cohort reported thus far, the effect was weaker than that observed in prior studies. Indeed, within a given stage, p63 status did not predict survival in a clinically or statistically significant manner. CONCLUSIONS: It remains unclear whether this test should be integrated into routine MCC patient management.


Subject(s)
Biomarkers, Tumor/analysis , Carcinoma, Merkel Cell/mortality , Membrane Proteins/biosynthesis , Skin Neoplasms/mortality , Adult , Aged , Aged, 80 and over , Carcinoma, Merkel Cell/metabolism , Carcinoma, Merkel Cell/pathology , Female , Humans , Immunohistochemistry , Kaplan-Meier Estimate , Male , Membrane Proteins/analysis , Middle Aged , Neoplasm Staging , Proportional Hazards Models , Skin Neoplasms/metabolism , Skin Neoplasms/pathology
14.
J Chem Phys ; 139(4): 045104, 2013 Jul 28.
Article in English | MEDLINE | ID: mdl-23902029

ABSTRACT

Static and magic angle spinning (MAS) (2)H nuclear magnetic resonance experiments have been performed on a series of multilamellar dispersions of di-oleoyl-sn-glycero-3-phosphocholine/di-palmitoyl-sn-glycero-3-phosphocholine-d62/cholesterol in water to investigate the compositional fluctuations which occur in the region of the line of critical points for this ternary system. The strong dependence of the MAS line widths on temperature, sample composition, and spinning rate provides a direct measure of the magnitude of the fluctuations in the (2)H quadrupolar Hamiltonian. These data are analyzed in terms of models for critical fluctuations in composition leading to a value for the critical index for the correlation length, ν(c) = 0.628, consistent with a three dimensional Ising model.


Subject(s)
1,2-Dipalmitoylphosphatidylcholine/chemistry , Cholesterol/chemistry , Phosphatidylglycerols/chemistry , Magnetic Resonance Spectroscopy/methods , Phase Transition , Temperature
15.
Proc Natl Acad Sci U S A ; 108(33): 13716-21, 2011 Aug 16.
Article in English | MEDLINE | ID: mdl-21844338

ABSTRACT

Multiple human epidemiologic studies link caffeinated (but not decaffeinated) beverage intake with significant decreases in several types of cancer, including highly prevalent UV-associated skin carcinomas. The mechanism by which caffeine protects against skin cancer is unknown. Ataxia telangiectasia and Rad3-related (ATR) is a replication checkpoint kinase activated by DNA stresses and is one of several targets of caffeine. Suppression of ATR, or its downstream target checkpoint kinase 1 (Chk1), selectively sensitizes DNA-damaged and malignant cells to apoptosis. Agents that target this pathway are currently in clinical trials. Conversely, inhibition of other DNA damage response pathways, such as ataxia telangiectasia mutated (ATM) and BRCA1, promotes cancer. To determine the effect of replication checkpoint inhibition on carcinogenesis, we generated transgenic mice with diminished ATR function in skin and crossed them into a UV-sensitive background, Xpc(-/-). Unlike caffeine, this genetic approach was selective and had no effect on ATM activation. These transgenic mice were viable and showed no histological abnormalities in skin. Primary keratinocytes from these mice had diminished UV-induced Chk1 phosphorylation and twofold augmentation of apoptosis after UV exposure (P = 0.006). With chronic UV treatment, transgenic mice remained tumor-free for significantly longer (P = 0.003) and had 69% fewer tumors at the end of observation of the full cohort (P = 0.019), compared with littermate controls with the same genetic background. This study suggests that inhibition of replication checkpoint function can suppress skin carcinogenesis and supports ATR inhibition as the relevant mechanism for the protective effect of caffeinated beverage intake in human epidemiologic studies.


Subject(s)
Cell Cycle Proteins/antagonists & inhibitors , Keratinocytes/radiation effects , Protein Serine-Threonine Kinases/antagonists & inhibitors , Skin Neoplasms/prevention & control , Ultraviolet Rays/adverse effects , Animals , Apoptosis , Ataxia Telangiectasia Mutated Proteins , Caffeine/pharmacology , Cell Cycle Proteins/genetics , Checkpoint Kinase 1 , Keratinocytes/cytology , Mice , Mice, Transgenic , Protein Kinases/metabolism , Protein Serine-Threonine Kinases/genetics , Skin Neoplasms/etiology , Skin Neoplasms/pathology
16.
J Chem Phys ; 131(17): 175103, 2009 Nov 07.
Article in English | MEDLINE | ID: mdl-19895044

ABSTRACT

Biological membranes contain a mixture of phospholipids with varying degrees of hydrocarbon chain unsaturation. Mixtures of long chain saturated and unsaturated lipids with cholesterol have attracted a lot of attention because of the formation of two coexisting fluid bilayer phases in such systems over a broad range of temperature and composition. Interpretation of the phase behavior of such ternary mixtures must be based on a thorough understanding of the phase behavior of the binary mixtures formed with the same components. This article describes the phase behavior of mixtures of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) with 1,2-di-d(31)-palmitoyl-sn-glycero-3-phosphocholine (DPPC) between -20 and 50 degrees C. Particular attention has been paid to the phase coexistence below about 16 degrees C where the subgel phase appears. The changes in the shape of the spectrum (and its spectral moments) during the slow transformation process leads to the conclusion that below 16 degrees C the gel phase is metastable and the gel component of the two-phase mixture slowly transforms to the subgel phase with a slightly different composition. This results in a line of three-phase coexistence near 16 degrees C. Analysis of the transformation of the metastable gel domains into the subgel phase using the nucleation and growth model shows that the subgel domain growth is a two dimensional process.


Subject(s)
1,2-Dipalmitoylphosphatidylcholine/chemistry , Phosphatidylcholines/chemistry , Gels , Magnetic Resonance Spectroscopy , Phase Transition , Temperature , Time Factors
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