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1.
J Gay Lesbian Soc Serv ; 33(3): 300-319, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34121828

RESUMO

The focus of the phenomenological qualitative study was on the lived experiences of U.S. educators who identified as lesbian, gay, and bisexual (LGB). Life story data regarding stress, coping, and identity were gathered, triangulated, and analyzed from 24 U.S. educators who identified as LGB teachers, mentors, and coaches. Four themes resulted: (a) subscribing to a helping identity, (b) being effective as an educator, (c) experiencing different levels of support, and (d) being out about sexual orientation to different degrees. Recommendations for future research are provided.

2.
J Endocrinol ; 248(1): R19-R28, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33232264

RESUMO

Adipose tissue is usually laid down in small amounts in the foetus and is characterised as possessing small amounts of the brown adipose tissue-specific mitochondrial uncoupling protein (UCP)1. In adults, a primary factor determining the abundance and function of UCP1 is ambient temperature. Cold exposure causes activation and the rapid generation of heat through the free flow of protons across the mitochondria with no requirement to convert ADP to ATP. In rodents, housing at an ambient temperature below thermoneutrality promotes the appearance of beige like adipocytes. These arise as discrete regions of UCP1 containing cells in white fat depots. There is increasing evidence to show that to gain credible translational results on brown and beige fat function in rodent models that they should be housed at thermoneutrality. This not only reflects the type of environment in which humans spend a majority of their time, but is in accord with the rise of global temperature caused by industrialisation and the uncontrolled burning of fossil fuels. There is now good evidence in adult humans, that stimulating brown fat can improve glucose homeostasis which can be achieved either by nutritional or pharmacological interventions. The challenge, therefore, is to establish credible developmental models in animals maintained at thermoneutrality which will elucidate the true impact of nutrition. The primary focus should fall specifically on the components of breast milk and how these modulate long term effects on brown or beige fat development and function.


Assuntos
Tecido Adiposo Marrom/crescimento & desenvolvimento , Temperatura , Animais , Homeostase , Humanos , Leite/química , Saúde Reprodutiva , Proteína Desacopladora 1/fisiologia
3.
Adipocyte ; 8(1): 46-50, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-30463471

RESUMO

There is increasing evidence that the global rise in temperature is contributing to the onset of diabetes, which could be mediated by a concomitant reduction in brown fat activity. Brown (and beige) fat are characterised as possessing a unique mitochondrial protein uncoupling protein (UCP)1 that when activated can rapidly generate large amounts of heat. Primary environmental stimuli of UCP1 include cold-exposure and diet, leading to increased activity of the sympathetic nervous system and large amounts of lipid and glucose being oxidised by brown fat. The exact contribution remains controversial, although recent studies indicate that the amount of brown and beige fat in adult humans has been greatly underestimated. We therefore review the potential mechanisms by which glucose could be utilised within brown and beige fat in adult humans and the extent to which these are sensitive to temperature and diet. This includes the potential contribution from the peridroplet and cytoplasmic mitochondrial sub-fractions recently identified in brown fat, and whether a proportion of glucose oxidation could be UCP1-independent. It is thus predicted that as new methods are developed to assess glucose metabolism by brown fat, a more accurate determination of the thermogenic and non-thermogenic functions could be feasible in humans.


Assuntos
Tecido Adiposo Marrom/metabolismo , Mudança Climática/mortalidade , Glucose/metabolismo , Tecido Adiposo Bege/metabolismo , Adulto , Metabolismo dos Carboidratos , Diabetes Mellitus/etiologia , Metabolismo Energético , Feminino , Homeostase/fisiologia , Humanos , Masculino , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Obesidade/etiologia , Termogênese/fisiologia , Proteína Desacopladora 1/metabolismo
4.
F1000Res ; 72018.
Artigo em Inglês | MEDLINE | ID: mdl-30079236

RESUMO

Brown adipose tissue (BAT) possesses a unique uncoupling protein (UCP1) which, when activated, enables the rapid generation of heat and the oxidation of lipids or glucose or both. It is present in small amounts (~15-350 mL) in adult humans. UCP1 is rapidly activated at birth and is essential in preventing hypothermia in newborns, who rapidly generate large amounts of heat through non-shivering thermogenesis. Since the "re-discovery" of BAT in adult humans about 10 years ago, there has been an exceptional amount of research interest. This has been accompanied by the establishment of beige fat, characterised as discrete areas of UCP1-containing cells dispersed within white adipocytes. Typically, the amount of UCP1 in these depots is around 10% of the amount found in classic BAT. The abundance of brown/beige fat is reduced with obesity, and the challenge is to prevent its loss with ageing or to reactivate existing depots or both. This is difficult, as the current gold standard for assessing BAT function in humans measures radio-labelled glucose uptake in the fasted state and is usually dependent on cold exposure and the same subject can be found to exhibit both positive and negative scans with repeated scanning. Rodent studies have identified multiple pathways that may modulate brown/beige fat function, but their direct relevance to humans is constrained, as these studies typically are undertaken in cool-adapted animals. BAT remains a challenging organ to study in humans and is able to swiftly adapt to changes in the thermal environment and thus enable rapid changes in heat production and glucose oxidation.

5.
Sci Rep ; 8(1): 9628, 2018 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-29941966

RESUMO

Brown adipose tissue (BAT) undergoes pronounced changes after birth coincident with the loss of the BAT-specific uncoupling protein (UCP)1 and rapid fat growth. The extent to which this adaptation may vary between anatomical locations remains unknown, or whether the process is sensitive to maternal dietary supplementation. We, therefore, conducted a data mining based study on the major fat depots (i.e. epicardial, perirenal, sternal (which possess UCP1 at 7 days), subcutaneous and omental) (that do not possess UCP1) of young sheep during the first month of life. Initially we determined what effect adding 3% canola oil to the maternal diet has on mitochondrial protein abundance in those depots which possessed UCP1. This demonstrated that maternal dietary supplementation delayed the loss of mitochondrial proteins, with the amount of cytochrome C actually being increased. Using machine learning algorithms followed by weighted gene co-expression network analysis, we demonstrated that each depot could be segregated into a unique and concise set of modules containing co-expressed genes involved in adipose function. Finally using lipidomic analysis following the maternal dietary intervention, we confirmed the perirenal depot to be most responsive. These insights point at new research avenues for examining interventions to modulate fat development in early life.


Assuntos
Tecido Adiposo Marrom/crescimento & desenvolvimento , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/crescimento & desenvolvimento , Tecido Adiposo Branco/metabolismo , Suplementos Nutricionais , Mães , Transcrição Gênica/efeitos dos fármacos , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Branco/efeitos dos fármacos , Animais , Mineração de Dados , Feminino , Redes Reguladoras de Genes/efeitos dos fármacos , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Família Multigênica/genética , Ovinos
6.
J Clin Microbiol ; 56(8)2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29743308

RESUMO

The tick-borne protozoan Babesia microti is responsible for more than 200 cases of transfusion-transmitted babesiosis (TTB) infection in the United States that have occurred over the last 30 years. Measures to mitigate the risk of TTB include nucleic acid testing (NAT) and B. microti antibody testing. A fully automated prototype B. microti antibody test was developed on the Architect instrument. The specificity was determined to be 99.98% in volunteer blood donors (n = 28,740) from areas considered to have low endemicity for B. microti The sensitivity of the prototype test was studied in experimentally infected macaques; a total of 128 samples were detected as positive whereas 125 were detected as positive with an indirect fluorescent antibody (IFA) test; additionally, 83 (89.2%) of the PCR-positive samples were detected in contrast to 81 (87.1%) using an IFA test. All PCR-positive samples that tested negative in the prototype antibody test were preseroconversion period samples. Following seroconversion, periods of intermittent parasitemia occurred; 17 PCR-negative samples drawn in between PCR-positive bleed dates tested positive both by the prototype test (robust reactivity) and IFA test (marginal reactivity) prior to the administration of therapeutic drugs, indicating that the PCR test failed to detect samples from persistently infected macaques. The prototype assay detected 56 of 58 (96.6%) human subjects diagnosed with clinical babesiosis by both PCR and IFA testing. Overall, the prototype anti-Babesia assay provides a highly sensitive and specific test for the diagnosis of B. microti infection. While PCR is preferred for detection of window-period parasitemia, antibody tests detect infected subjects during periods of low-level parasitemia.


Assuntos
Anticorpos Antiprotozoários/sangue , Babesia microti/isolamento & purificação , Babesiose/diagnóstico , Imunoensaio/normas , Parasitemia/diagnóstico , Animais , Anticorpos Antiprotozoários/imunologia , Babesia microti/genética , Babesia microti/imunologia , Modelos Animais de Doenças , Técnica Indireta de Fluorescência para Anticorpo/normas , Humanos , Imunoensaio/instrumentação , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Macaca , Programas de Rastreamento , Reação em Cadeia da Polimerase , Sensibilidade e Especificidade , Soroconversão , Reação Transfusional/prevenção & controle
7.
J Endocrinol ; 238(1): R53-R62, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29789429

RESUMO

Although brown adipose tissue (BAT) is one of the smallest organs in the body, it has the potential to have a substantial impact on both heat production as well as fat and carbohydrate metabolism. This is most apparent at birth, which is characterised with the rapid appearance and activation of the BAT specific mitochondrial uncoupling protein (UCP)1 in many large mammals. The amount of brown fat then gradually declines with age, an adaptation that can be modulated by the thermal environment. Given the increased incidence of maternal obesity and its potential transmission to the mother's offspring, increasing BAT activity in the mother could be one mechanism to prevent this cycle. To date, however, all rodent studies investigating maternal obesity have been conducted at standard laboratory temperature (21°C), which represents an appreciable cold challenge. This could also explain why offspring weight is rarely increased, suggesting that future studies would benefit from being conducted at thermoneutrality (~28°C). It is also becoming apparent that each fat depot has a unique transcriptome and show different developmental pattern, which is not readily apparent macroscopically. These differences could contribute to the retention of UCP1 within the supraclavicular fat depot, the most active depot in adult humans, increasing heat production following a meal. Despite the rapid increase in publications on BAT over the past decade, the extent to which modifications in diet and/or environment can be utilised to promote its activity in the mother and/or her offspring remains to be established.


Assuntos
Tecido Adiposo Marrom/embriologia , Tecido Adiposo Marrom/fisiologia , Reprodução/fisiologia , Tecido Adiposo Marrom/crescimento & desenvolvimento , Animais , Peso Corporal/fisiologia , Feminino , Humanos , Masculino , Obesidade/metabolismo , Obesidade/fisiopatologia , Gravidez , Complicações na Gravidez/metabolismo , Complicações na Gravidez/fisiopatologia , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Termogênese/fisiologia
8.
Metabolism ; 81: 63-70, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29155135

RESUMO

Global rates of obesity continue to rise and are necessarily the consequence of a long-term imbalance between energy intake and energy expenditure. This is the result of an expansion of adipose tissue due to both the hypertrophy of existing adipocytes and hyperplasia of adipocyte pre-cursors. Exercise elicits numerous physiological benefits on adipose tissue, which are likely to contribute to the associated cardiometabolic benefits. More recently it has been demonstrated that exercise, through a range of mechanisms, induces a phenotypic switch in adipose tissue from energy storing white adipocytes to thermogenic beige adipocytes. This has generated the hypothesis that the process of adipocyte 'browning' may partially underlie the improved cardiometabolic health in physically active populations. Interestingly, 'browning' also occurs in response to various stressors and could represent an adaptive response. In the context of exercise, it is not clear whether the appearance of beige adipocytes is metabolically beneficial or whether they occur as a transient adaptive process to exercise-induced stresses. The present review discusses the various mechanisms (e.g. fatty acid oxidation during exercise, decreased thermal insulation, stressors and angiogenesis) by which the exercise-induced 'browning' process may occur.


Assuntos
Adaptação Fisiológica , Tecido Adiposo Marrom/fisiologia , Exercício Físico , Tecido Adiposo Branco/fisiologia , Adiposidade , Humanos , Neovascularização Fisiológica , Estresse Fisiológico
9.
Endocrinology ; 158(7): 2212-2225, 2017 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-28431116

RESUMO

Brown adipose tissue acting through a unique uncoupling protein (UCP1) has a critical role in preventing hypothermia in newborn sheep but is then thought to rapidly disappear during postnatal life. The extent to which the anatomical location of fat influences postnatal development and thermogenic function in adulthood, particularly following feeding, is unknown, and we examined both in our study. Changes in gene expression of functionally important pathways (i.e., thermogenesis, development, adipogenesis, and metabolism) were compared between sternal and retroperitoneal fat depots together with a representative skeletal muscle over the first month of postnatal life, coincident with the loss of brown fat and the accumulation of white fat. In adult sheep, implanted temperature probes were used to characterize the thermogenic response of fat and muscle to feeding and the effects of reduced or increased adiposity. UCP1 was more abundant in sternal fat than in retroperitoneal fat and was retained only in the sternal depot of adults. Distinct differences in the abundance of gene pathway markers were apparent between tissues, with sternal fat exhibiting some similarities with muscle that were not apparent in the retroperitoneal depot. In adults, the postprandial rise in temperature was greater and more prolonged in sternal fat than in retroperitoneal fat and muscle, a difference that was maintained with altered adiposity. In conclusion, sternal adipose tissue retains UCP1 into adulthood, when it shows a greater thermogenic response to feeding than do muscle and retroperitoneal fat. Sternal fat may be more amenable to targeted interventions that promote thermogenesis in large mammals.


Assuntos
Adipogenia/fisiologia , Tecido Adiposo Marrom/fisiologia , Termogênese/fisiologia , Tecido Adiposo Marrom/anatomia & histologia , Adiposidade , Animais , Peso Corporal , Ingestão de Alimentos/fisiologia , Feminino , Gordura Intra-Abdominal/anatomia & histologia , Gordura Intra-Abdominal/fisiologia , Músculo Esquelético/metabolismo , Tamanho do Órgão , Ovinos , Tórax/metabolismo
10.
Arch Sex Behav ; 46(2): 489-501, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26732606

RESUMO

We examined the interplay between husbands' and wives' positive and negative nonsexual interpersonal behaviors, frequency of sexual intercourse, sexual satisfaction, and feelings of marital satisfaction. To do this, we conducted an in-depth face-to-face interview and completed a series of telephone diaries with 105 couples during their second, third, and fourteenth years of marriage. Consistent with the argument that women's sexual response is tied to intimacy (Basson, 2000), multilevel analyses revealed that husbands' positive interpersonal behaviors directed toward their wives-but not wives' positivity nor spouses' negative behaviors (regardless of gender)-predicted the frequency with which couples engaged in intercourse. The frequency of sexual intercourse and interpersonal negativity predicted both husbands' and wives' sexual satisfaction; wives' positive behaviors were also tied to husbands' sexual satisfaction. When spouses' interpersonal behaviors, frequency of sexual intercourse, and sexual satisfaction were considered in tandem, all but the frequency of sexual intercourse were associated with marital satisfaction. When it comes to feelings of marital satisfaction, therefore, a satisfying sex life and a warm interpersonal climate appear to matter more than does a greater frequency of sexual intercourse. Collectively, these findings shed much-needed light on the interplay between the nonsexual interpersonal climate of marriage and spouses' sexual relationships.


Assuntos
Casamento/psicologia , Satisfação Pessoal , Comportamento Sexual/psicologia , Cônjuges/psicologia , Adulto , Feminino , Humanos , Masculino
11.
Annu Rev Nutr ; 35: 295-320, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26076904

RESUMO

There are three different types of adipose tissue (AT)-brown, white, and beige-that differ with stage of development, species, and anatomical location. Of these, brown AT (BAT) is the least abundant but has the greatest potential impact on energy balance. BAT is capable of rapidly producing large amounts of heat through activation of the unique uncoupling protein 1 (UCP1) located within the inner mitochondrial membrane. White AT is an endocrine organ and site of lipid storage, whereas beige AT is primarily white but contains some cells that possess UCP1. BAT first appears in the fetus around mid-gestation and is then gradually lost through childhood, adolescence, and adulthood. We focus on the interrelationships between adipocyte classification, anatomical location, and impact of diet in early life together with the extent to which fat development differs between the major species examined. Ultimately, novel dietary interventions designed to reactivate BAT could be possible.


Assuntos
Tecido Adiposo Marrom/crescimento & desenvolvimento , Tecido Adiposo Marrom/fisiologia , Adipócitos/classificação , Adipócitos/fisiologia , Tecido Adiposo/embriologia , Tecido Adiposo/crescimento & desenvolvimento , Tecido Adiposo Marrom/embriologia , Tecido Adiposo Branco/fisiologia , Animais , Dieta , Metabolismo Energético/fisiologia , Epigênese Genética , Feminino , Desenvolvimento Fetal , Idade Gestacional , Humanos , Canais Iônicos/fisiologia , Fenômenos Fisiológicos da Nutrição Materna , Proteínas Mitocondriais/fisiologia , Gravidez , Termogênese/fisiologia , Proteína Desacopladora 1
12.
Proc Nutr Soc ; 71(3): 363-70, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22704581

RESUMO

Since the rediscovery of brown adipose tissue (BAT) in adult human subjects in 2007, there has been a dramatic resurgence in research interest in its role in heat production and energy balance. This has coincided with a reassessment of the origins of BAT and the suggestion that brown preadipocytes could share a common lineage with skeletal myoblasts. In precocial newborns, such as sheep, the onset of non-shivering thermogenesis through activation of the BAT-specific uncoupling protein 1 (UCP1) is essential for effective adaptation to the cold exposure of the extra-uterine environment. This is mediated by a combination of endocrine adaptations which accompany normal parturition at birth and further endocrine stimulation from the mother's milk. Three distinct adipose depots have been identified in all species studied to date. These contain either primarily white, primarily brown or a mix of brown and white adipocytes. The latter tissue type is present, at least, in the fetus and, thereafter, appears to take on the characteristics of white adipose tissue during postnatal development. It is becoming apparent that a range of organ-specific mechanisms can promote UCP1 expression. They include the liver, heart and skeletal muscle, and involve unique endocrine systems that are stimulated by cold exposure and/or exercise. These multiple pathways that promote BAT function vary with age and between species that may determine the potential to be manipulated in early life. Such interventions could modify, or reverse, the normal ontogenic pathway by which BAT disappears after birth, thereby facilitating BAT thermogenesis through the life cycle.


Assuntos
Adaptação Fisiológica , Tecido Adiposo Marrom/crescimento & desenvolvimento , Temperatura Baixa , Sistema Endócrino/fisiologia , Metabolismo Energético , Canais Iônicos/metabolismo , Proteínas Mitocondriais/metabolismo , Termogênese , Adipócitos , Tecido Adiposo Marrom/embriologia , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco , Animais , Humanos , Mamíferos , Proteína Desacopladora 1
13.
Congenit Heart Dis ; 7(2): 151-9, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22011241

RESUMO

Background. Variants of several genes encoding transcription modulators, signal transduction, and structural proteins are known to cause Mendelian congenital heart disease (CHD). NKX2-5 and GATA4 were the first CHD-causing genes identified by linkage analysis in large affected families. Mutations of TBX5 cause Holt-Oram syndrome, which includes CHD as a clinical feature. All three genes have a well-established role in cardiac development. Design. In order to investigate the possible role of multiple mutations in CHD, a combined mutation screening was performed in NKX2-5, GATA4, and TBX5 in the same patient cohort. Samples from a cohort of 331 CHD patients were analyzed by polymerase chain reaction, double high-performance liquid chromatography and sequencing in order to identify changes in the NKX2-5, GATA4, and TBX5 genes. Results. Two cases of multiple heterozygosity of putative disease-causing mutations were identified. One patient was found with a novel L122P NKX2-5 mutation in combination with the private A1443D mutation of MYH6. A patient heterozygote for a D425N GATA4 mutation carries also a private mutation of the MYH6 gene (V700M). Conclusions. In addition to reporting two novel mutations of NKX2-5 in CHD, we describe families where multiple individual mutations seem to have an additive effect over the pathogenesis of CHD. Our findings highlight the usefulness of multiple gene mutational analysis of large CHD cohorts.


Assuntos
Fator de Transcrição GATA4/genética , Cardiopatias Congênitas/genética , Proteínas de Homeodomínio/genética , Proteínas com Domínio T/genética , Fatores de Transcrição/genética , Miosinas Cardíacas/genética , Estudos de Coortes , Análise Mutacional de DNA , Predisposição Genética para Doença/genética , Testes Genéticos , Heterozigoto , Proteína Homeobox Nkx-2.5 , Humanos , Cadeias Pesadas de Miosina/genética , Mutação Puntual/genética
14.
Am Psychol ; 65(8): 841-54, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21058803

RESUMO

Empathy is reported in the research literature as a necessary factor in counseling and psychotherapy, but psychologists have historically interpreted empathy through an exclusively individual focus. Most of the research on empathy has been predicated on a definition of empathy as occurring when one person vicariously experiences the feelings, perceptions, and thoughts of another. In Western cultures, the study of empathy focuses exclusively on the individual, whereas in traditional non-Western cultures, empathy more typically involves an inclusive perspective focusing on the individual and significant others in the societal context. This article explores the reframing of "empathy," based on an individualistic perspective, into "inclusive cultural empathy," based on a more relationship-centered perspective, as an alternative interpretation of the empathic process. Psychologists are both the problem and the solution to this dilemma, and the authors call upon the field to take leadership in applying this "inclusive cultural empathy" model.


Assuntos
Distinções e Prêmios , Aconselhamento , Diversidade Cultural , Cooperação Internacional , Liderança , Psicologia , Sociedades Científicas , Humanos , Estados Unidos
15.
Hum Mol Genet ; 19(20): 4007-16, 2010 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-20656787

RESUMO

Congenital heart defects (CHD) are collectively the most common form of congenital malformation. Studies of human cases and animal models have revealed that mutations in several genes are responsible for both familial and sporadic forms of CHD. We have previously shown that a mutation in MYH6 can cause an autosomal dominant form of atrial septal defect (ASD), whereas others have identified mutations of the same gene in patients with hypertrophic and dilated cardiomyopathy. In the present study, we report a mutation analysis of MYH6 in patients with a wide spectrum of sporadic CHD. The mutation analysis of MYH6 was performed in DNA samples from 470 cases of isolated CHD using denaturing high-performance liquid chromatography and sequence analysis to detect point mutations and small deletions or insertions, and multiplex amplifiable probe hybridization to detect partial or complete copy number variations. One non-sense mutation, one splicing site mutation and seven non-synonymous coding mutations were identified. Transfection of plasmids encoding mutant and non-mutant green fluorescent protein-MYH6 fusion proteins in mouse myoblasts revealed that the mutations A230P and A1366D significantly disrupt myofibril formation, whereas the H252Q mutation significantly enhances myofibril assembly in comparison with the non-mutant protein. Our data indicate that functional variants of MYH6 are associated with cardiac malformations in addition to ASD and provide a novel potential mechanism. Such phenotypic heterogeneity has been observed in other genes mutated in CHD.


Assuntos
Miosinas Cardíacas/genética , Cardiopatias Congênitas/genética , Comunicação Interatrial/genética , Miofibrilas/metabolismo , Cadeias Pesadas de Miosina/genética , Animais , Miosinas Cardíacas/metabolismo , Cardiomiopatia Dilatada/genética , Cromatografia Líquida de Alta Pressão , Variações do Número de Cópias de DNA , Análise Mutacional de DNA , Estudos de Associação Genética , Humanos , Camundongos , Mutação , Mioblastos/citologia , Miofibrilas/genética , Cadeias Pesadas de Miosina/metabolismo , Plasmídeos , Transfecção
16.
Hum Mol Genet ; 17(2): 256-65, 2008 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-17947298

RESUMO

Atrial septal defect (ASD) is one of the most frequent congenital heart defects (CHDs) with a variable phenotypic effect depending on the size of the septal shunt. We identified two pedigrees comprising 20 members segregating isolated autosomal dominant secundum ASD. By genetic mapping, we identified the gene-encoding alpha-cardiac actin (ACTC1), which is essential for cardiac contraction, as the likely candidate. A mutation screen of the coding regions of ACTC1 revealed a founder mutation predicting an M123V substitution in affected individuals of both pedigrees. Functional analysis of ACTC1 with an M123V substitution shows a reduced affinity for myosin, but with retained actomyosin motor properties. We also screened 408 sporadic patients with CHDs and identified a case with ASD and a 17-bp deletion in ACTC1 predicting a non-functional protein. Morpholino (MO) knockdown of ACTC1 in chick embryos produces delayed looping and reduced atrial septa, supporting a developmental role for this protein. The combined results indicate, for the first time, that ACTC1 mutations or reduced ACTC1 levels may lead to ASD without signs of cardiomyopathy.


Assuntos
Actinas/genética , Comunicação Interatrial/genética , Comunicação Interatrial/metabolismo , Actinas/química , Actinas/metabolismo , Substituição de Aminoácidos , Animais , Embrião de Galinha , Pré-Escolar , Feminino , Deleção de Genes , Coração/embriologia , Humanos , Lactente , Masculino , Mutagênese Sítio-Dirigida , Miosinas/metabolismo , Linhagem
17.
Biochemistry ; 45(47): 14155-65, 2006 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-17115710

RESUMO

Structure-function studies of antibody-antigen systems include the identification of amino acid residues in the antigen that interact with an antibody and elucidation of their individual contributions to binding affinity. We used fluorescence correlation spectroscopy (FCS) and alanine-scanning mutagenesis to characterize the interactions of brain natriuretic peptide (BNP) with two monoclonal antibodies. Human BNP is a 32 amino acid residue long cyclic polypeptide with the ring structure confined between cysteines in positions 10 and 26. It is an important cardiovascular hormone and a valuable diagnostic cardiac marker. We compare the binding strength of the N-terminus Alexa488-labeled BNP, native cyclic BNP, BNP alanine-substituted mutants, linear BNP, and its short fragments to determine the individual contributions of amino acid residues included in the continuous antigenic epitopes that are recognized by two different monoclonal antibodies raised toward BNP. Implementation of FCS for these studies offers all of the advantages of solution phase measurements, including high sensitivity, simplicity of manipulation with reagents, and elimination of solid phase interferences or separation steps. Significant differences in the molecular masses of the free and antibody bound BNP results in a substantial ( approximately 2.5-times) increase in the diffusion rates. Determination of the binding constants and inhibition effects by measuring the diffusion rates of the ligand at the single molecule level introduces the ultimate opportunity for researching systems where the fluorescence intensity and/or fluorescence anisotropy do not change upon interaction of the ligand with the protein. Monoclonal antibodies 106.3 and BC203 demonstrate high affinities to BNP and bind two distant epitopes forming robust antibody sandwiches. Both antibodies are used in Abbott diagnostic assays on AxSYM, IMx, and Architect platforms.


Assuntos
Anticorpos Monoclonais/química , Mapeamento de Epitopos , Peptídeo Natriurético Encefálico/imunologia , Espectrometria de Fluorescência/métodos , Animais , Anticorpos Monoclonais/imunologia , Linhagem Celular , Corantes Fluorescentes , Camundongos
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