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An In Silico Analysis of Troponin I Mutations in Hypertrophic Cardiomyopathy of Indian Origin  [PDF]
Gayatri Ramachandran, Manoj Kumar, Deepa Selvi Rani, Venkateshwari Annanthapur, Narasimhan Calambur, Pratibha Nallari, Punit Kaur
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0070704
Abstract: Hypertrophic Cardiomyopathy (HCM) is an autosomal dominant disorder of the myocardium which is hypertrophied resulting in arrhythmias and heart failure leading to sudden cardiac death (SCD). Several sarcomeric proteins and modifier genes have been implicated in this disease. Troponin I, being a part of the Troponin complex (troponin I, troponin C, troponin T), is an important gene for sarcomeric function. Four mutations (1 novel) were identified in Indian HCM cases, namely, Pro82Ser, Arg98Gln, Arg141Gln and Arg162Gln in Troponin I protein, which are in functionally significant domains. In order to analyse the effect of the mutations on protein stability and protein-protein interactions within the Troponin complex, an in silico study was carried out. The freely available X-ray crystal structure (PDB ID: 1JIE) was used as the template to model the protein followed by loop generation and development of troponin complex for both the troponin I wild type and four mutants (NCBI ID: PRJNA194382). The structural study was carried out to determine the effect of mutation on the structural stability and protein-protein interactions between three subunits in the complex. These mutations, especially the arginine to glutamine substitutions were found to result in local perturbations within the troponin complex by creating/removing inter/intra molecular hydrogen bonds with troponin T and troponin C. This has led to a decrease in the protein stability and loss of important interactions between the three subunits. It could have a significant impact on the disease progression when coupled with allelic heterogeneity which was observed in the cases carrying these mutations. However, this can be further confirmed by functional studies on protein levels in the identified cases.
Troponin I release at rest and after exercise in patients with hypertrophic cardiomyopathy and the effect of betablockade
AM Pop, Gheorghe;Cramer, Etienne;Timmermans, Janneke;Bos, Hans;Verheugt, Freek WA;
Archivos de cardiología de México , 2006,
Abstract: purpose of the work: in patients with hypertrophic cardiomyopathy ischemia may occur due to massive heart weight, myocyte disarray or small vessel disease. we detected elevated troponin levels in some of these patients and hypothesized that troponin release would rise after exercise and diminish after betablockade. methods and results: in 5 of 7 young patients (6 males) with hypertrophic cardiomyopathy and no overt coronary artery disease we found elevated troponin levels after physical exercise; the peak was between 6 and 9 hours and levels returned to pre-exercise values within 24 hours. troponin release was consistently diminished after use of a betablocker. conclusions: increased troponin release may be present in patients with hypertrophic cardiomyopathy and is temporarily enhanced by exercise and diminishes with betablockade.
Inherited cardiomyopathies caused by troponin mutations
Qun-Wei Lu,Xiao-Yan Wu,Sachio Morimoto,
Qun-Wei Lu
,Xiao-Yan Wu,Sachio Morimoto

老年心脏病学杂志(英文版) , 2013,
Abstract: Genetic investigations of cardiomyopathy in the recent two decades have revealed a large number of mutations in the genes encoding sarcomeric proteins as a cause of inherited hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), or restrictive cardiomyopathy (RCM). Most functional analyses of the effects of mutations on cardiac muscle contraction have revealed significant changes in the Ca2+-regulatory mechanism, in which cardiac troponin (cTn) plays important structural and functional roles as a key regulatory protein. Over a hundred mutations have been identified in all three subunits of cTn, i.e., cardiac troponins T, I, and C. Recent studies on cTn mutations have provided plenty of evidence that HCM- and RCM-linked mutations increase cardiac myofilament Ca2+ sensitivity, while DCM-linked mutations decrease it. This review focuses on the functional consequences of mutations found in cTn in terms of cardiac myofilament Ca2+ sensitivity, ATPase activity, force generation, and cardiac troponin I phosphorylation, to understand potential molecular and cellular pathogenic mechanisms of the three types of inherited cardiomyopathy.
Inherited cardiomyopathies caused by troponin mutations
Qun-Wei Lu,Xiao-Yan Wu,Sachio Morimoto
老年心脏病学杂志(英文版) , 2013,
Abstract: Genetic investigations of cardiomyopathy in the recent two decades have revealed a large number of mutations in the genes encoding sarcomeric proteins as a cause of inherited hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), or restrictive cardiomyopathy (RCM). Most functional analyses of the effects of mutations on cardiac muscle contraction have revealed significant changes in the Ca2+-regulatory mechanism, in which cardiac troponin (cTn) plays important structural and functional roles as a key regulatory protein. Over a hundred mutations have been identified in all three subunits of cTn, i.e., cardiac troponins T, I, and C. Recent studies on cTn mutations have provided plenty of evidence that HCM- and RCM-linked mutations increase cardiac myofilament Ca2+ sensitivity, while DCM-linked mutations decrease it. This review focuses on the functional consequences of mutations found in cTn in terms of cardiac myofilament Ca2+ sensitivity, ATPase activity, force generation, and cardiac troponin I phosphorylation, to understand potential molecular and cellular pathogenic mechanisms of the three types of inherited cardiomyopathy.
Cardiomiopatía Hipertrófica familiar: Genes, mutaciones y modelos animales. Revisión
Ramírez,Carlos Darío; Padrón,Raúl;
Investigación Clínica , 2004,
Abstract: abstract hypertrophic cardiomyopathy (hcm) is an autosomal dominant disease, which may afflict as many as 1 in 500 subjects (0.2%), being probably the most common hereditary cardiovascular disease and the most common cause of sudden cardiac death (scd). hypertrophic cardiomyopathy is characterized by the presence of unexplained left ventricular hypertrophy (in absence of hypertension, valvular disease, etc), which is usually asymmetric and involves the ventricular septum. molecular genetic studies have identified eleven genes that code proteins of the sarcomere that are associated with the hcm; the b-myosin heavy chain gene (myh7), a-myosin heavy chain (myh6), cardiac troponin t (tnnt2); cardiac troponin c (tnnc1), a-tropomyosin (tpm1), myosin binding protein-c (mybpc3), cardiac troponin (tnni3), essential and regulatory light chain genes (myl3 and myl2, respectively), cardiac a-actin gene (actc) and titin (ttn). the objective of this paper is the revision of the current state of the knowledge on (1) the organization and mutations of the hcm causing genes and their proteins and (2) the animal models developed for the study of the genes, mutations and proteins in the hypertrophic cardiomyopathy.
On Native Origin of the American Indians  [PDF]
Tianxi Sun
Open Journal of Applied Sciences (OJAppS) , 2016, DOI: 10.4236/ojapps.2016.69061
Abstract: There have been controversies over differing opinions in the source of the American Indians. In this paper, the writer criticized the so-called classical theory that the remote ancestors of the American Indians entered America from Asia through the Bering Straits 14,000 ~ 20,000 years ago, worn their “clothes” and carried kindling during the late Paleolithic, no matter how by “boat” across the Bering Sea or by foot through a “Bering Land Bridge” which might once link up Asia and North America during glacial period; and independently proposed a new hypothesis that American Indians might be originated from the Western Rift Valley of North America. On the basis of locus distribution of American ancient human’s remnants, the writer pointed out that American ancient humans might be first originated at Yukon Territory of Canada within the Western Rift Valley of North America (the Basin & Range Province), and then migrated south ward (Yukon Territory → Mojave Desert → Mexico → Peru → Chile). Moreover, American Indians would have long been a presence for 40,000 years, or even 100,000 ~ 200,000 years in the American continents. So far, the logical basis which American Indians came from Asia 14,000 ~ 20,000 years ago was crushed, and derived two inferences: 1) American Indians might be originated from the Western Rift Valley of North America; 2) Only the Eskimo might be the mover eastward from Asia, because of their gene B.
Indians culture in the tourism of Ontario  [PDF]
Besermenji Sne?ana,Mili? Nata?a,Mulec Ivo
Journal of the Geographical Institute Jovan Cvijic, SASA , 2011, DOI: 10.2298/ijgi1103119b
Abstract: The first association to potential tourists, when they mention Ontario or Canada, is endless and untouched natural area. Numerous forest areas and beautiful lakes, wild animals moving freely in these expanses of the famous Niagara Falls are important part of Ontario tourism offer. Regarding cultural assets of Ontario and of the entire Canada, it may not have old city quarters as Europe, but it certainly has a long history. This history includes Indians whose customs and culture are very interesting for tourists.
Troponin and Anti-Troponin Autoantibody Levels in Patients with Ventricular Noncompaction  [PDF]
Hatice Betül Erer, Tolga Sinan Güven?, Ahu Sarbay Kemik, Hale Yaka Y?lmaz, ?eref Kul, Servet Altay, Nurten Sayar, Yüksel Kaya, Mehmet Eren
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0057648
Abstract: Ventricular hypertrabeculation/noncompaction is a morphologic and functional anomaly of myocardium characterized by prominent trabeculae accompanied by deep recessus. Dilated cardiomyopathy with left ventricular failure is observed in these patients, while the cause or pathophysiologic nature of this complication is not known. Anti-troponin antibodies are formed against circulating cardiac troponins after an acute coronary event or conditions associated with chronic myocyte necrosis, such as dilated cardiomyopathy. In present study, we aimed to investigate cardiac troponins and anti troponin autoantibodies in ventricular noncompaction/hypertrabeculation patients with/without reduced ejection fraction. A total of 50 patients with ventricular noncompaction and 23 healthy volunteers were included in this study. Noncompaction/hypertrabeculation was diagnosed with two-dimensional echocardiography using appropriate criteria. Depending on ejection fraction, patients were grouped into noncompaction with preserved EF (LVEF >50%, n = 24) and noncompaction with reduced EF (LVEF <35%, n = 26) groups. Troponin I, troponin T, anti-troponin I IgM and anti-troponin T IgM were measured with sandwich immunoassay method using a commercially available kit. Patients with noncompaction had significantly higher troponin I (28.98±9.21 ng/ml in NCNE group and 28.11±10.42 ng/ml in NCLE group), troponin T (22.17±6.97 pg/ml in NCNE group and 22.78±7.76 pg/ml in NCLE group) and antitroponin I IgM (1.92±0.43 μg/ml in NCNE group and 1.79±0.36 μg/ml in NCLE group) levels compared to control group, while antitroponin T IgM and IgG were only elevated in patients with noncompaction and reduced EF (15.81±6.52 μg/ml for IgM and 16.46±6.25 μg/ml for IgG). Elevated cardiac troponins and anti-troponin I autoantibodies were observed in patients with noncompaction preceding the decline in systolic function and could indicate ongoing myocardial damage in these patients.
Trachoma among the Yanomami Indians
Paula, J.S.;Medina, N.H.;Cruz, A.A.V.;
Brazilian Journal of Medical and Biological Research , 2002, DOI: 10.1590/S0100-879X2002001000007
Abstract: the yanomami are one of the last primitive groups of indians living in brazil. they have almost no contact with other cultures. the epidemiology of eye disease among yanomami is virtually unknown. for the first time, a trachoma survey was conducted among yanomami indians in the state of amazonas near the venezuelan border of the brazilian rain forest. ophthalmic examination was carried out on a total of 613 individuals (338 males and 275 females) from eight yanomami villages along the marauiá river located in the upper rio negro basin. age was classified into three categories (children, adults, and elderly) and trachoma was classified into five grades: follicular, inflammatory intense, cicatricial, trichiasis, and corneal opacity. trachoma was endemic in all villages visited. overall, 30.3% of the subjects had trachoma. females were significantly more affected (37.4%) than males (23.9%). the inflammatory trachoma rate reached 24.9% in children and the cicatricial form increased with age, reaching 13.9% among adults and 35.21% among the elderly. trichiasis or corneal opacities were not detected and treatment of the entire population was initiated with 1 g azithromycin. the detection of endemic trachoma among the yanomami is relevant for the understanding of the epidemiology of this disease in the brazilian rain forest and underscores the necessity for a program of trachoma control in this region.
Trachoma among the Yanomami Indians  [cached]
Paula J.S.,Medina N.H.,Cruz A.A.V.
Brazilian Journal of Medical and Biological Research , 2002,
Abstract: The Yanomami are one of the last primitive groups of Indians living in Brazil. They have almost no contact with other cultures. The epidemiology of eye disease among Yanomami is virtually unknown. For the first time, a trachoma survey was conducted among Yanomami Indians in the State of Amazonas near the Venezuelan border of the Brazilian rain forest. Ophthalmic examination was carried out on a total of 613 individuals (338 males and 275 females) from eight Yanomami villages along the Marauiá River located in the upper Rio Negro Basin. Age was classified into three categories (children, adults, and elderly) and trachoma was classified into five grades: follicular, inflammatory intense, cicatricial, trichiasis, and corneal opacity. Trachoma was endemic in all villages visited. Overall, 30.3% of the subjects had trachoma. Females were significantly more affected (37.4%) than males (23.9%). The inflammatory trachoma rate reached 24.9% in children and the cicatricial form increased with age, reaching 13.9% among adults and 35.21% among the elderly. Trichiasis or corneal opacities were not detected and treatment of the entire population was initiated with 1 g azithromycin. The detection of endemic trachoma among the Yanomami is relevant for the understanding of the epidemiology of this disease in the Brazilian rain forest and underscores the necessity for a program of trachoma control in this region.
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