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1.
J Hum Nutr Diet ; 36(3): 1111-1120, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36000222

RESUMO

BACKGROUND: Although in vitro and animal studies have shown that iron loading in pancreatic beta cells impairs insulin secretion, no human studies have documented the acute effects of oral iron on beta-cell insulin secretory capacity. In the present study, we determined beta-cell insulin secretory capacity at baseline and after a single oral dose of iron (ferrous sulphate, 120 mg elemental iron) in healthy male individuals. METHODS: Fifteen healthy male volunteers underwent an oral glucose tolerance test (OGTT) to document baseline glucose tolerance and insulin secretion kinetics (baseline OGTT). One week later, the same subjects underwent a second OGTT, 2 h after an oral dose of ferrous sulphate (120 mg of elemental iron) (post-iron OGTT). Changes in disposition index, insulin secretion kinetics, glucose tolerance, insulin resistance, insulin clearance and iron-related parameters in serum were determined. RESULTS: Compared to baseline OGTT, the areas under the curve (AUC) for serum iron and transferrin saturation increased by 125% and 118%, respectively, in the post-iron OGTT. The disposition index decreased by 20% (p = 0.009) and the AUC for glucose concentrations increased by 5.7% (p < 0.001) during the post-iron OGTT. The insulin secretion rate was marginally lower during the first hour (-3.5%, p = 0.63), but became significantly higher during the second hour (22%, p = 0.005) of the post-iron OGTT. Insulin resistance and insulin clearance rate were not affected by iron intake. CONCLUSIONS: The decrease in disposition index and glucose tolerance observed after the oral dose of iron points to an acute iron-induced impairment in pancreatic beta-cell insulin secretory capacity.


Assuntos
Diabetes Mellitus Tipo 2 , Resistência à Insulina , Células Secretoras de Insulina , Masculino , Humanos , Células Secretoras de Insulina/fisiologia , Glicemia , Ferro , Insulina
2.
Nutr Metab Cardiovasc Dis ; 31(5): 1486-1493, 2021 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-33744036

RESUMO

BACKGROUND AND AIMS: The use of Friedewald's formula to calculate serum low-density lipoprotein cholesterol (LDL-C) is well-known to have limitations. A modification of it, in 2013, has been proposed to be superior. However, it was not known whether LDL-C values (calculated by the modified formula) meet laboratory performance criteria for their estimation. This study aimed to evaluate this. METHODS AND RESULTS: LDL-C values were calculated for 129,821 lipid profiles, using both Friedewald's formula and its modified version. Kappa statistics and intra-class correlation coefficient (ICC) were used to determine degree of agreement between directly measured and calculated values for LDL-C. Bias and total percentage error of the values were calculated. LDL-C concentrations calculated by the modified formula showed a greater degree of agreement with directly measured values (kappa = 0.713) than those calculated by Friedewald's formula (kappa = 0.595). Both the formulae produced values with negative biases (-3.47 for the modified formula and -7.62 for Friedewald's formula) and total percentage errors above the recommended limit of 12% (15.57% for the modified formula and 21.77% for Friedewald's formula). ICC showed that values calculated by the modified formula showed a greater degree of agreement with directly measured values, across a range of LDL-C values. CONCLUSION: Calculated LDL-C values, using the modified formula, showed better agreement with directly measured values, and less bias and percentage total error than those obtained by use of Friedewald's formula. However, the percentage total error with use of the modified formula exceeded the recommended limit for LDL-C.


Assuntos
LDL-Colesterol/sangue , Dislipidemias/diagnóstico , Modelos Biológicos , Adulto , Biomarcadores/sangue , HDL-Colesterol/sangue , Dislipidemias/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Triglicerídeos/sangue
3.
Pharmacogenet Genomics ; 28(1): 31-35, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29087970

RESUMO

Clozapine is the drug of choice for treatment-resistant schizophrenia. However, its use is associated with variable clinical responses and serious adverse effects. Polymorphisms in genes encoding proteins involved in synaptic neurotransmission may account for such variability. Here, we studied independent and epistatic genetic associations of polymorphisms in DRD4 (120-bp duplication) and COMT (Val158Met) with clinical response to clozapine in people with treatment-resistant schizophrenia. We studied 93 participants who were on stable doses of clozapine for at least 12 weeks. A total score of less than or equal to 35 on the Brief Psychiatric Rating Scale was defined as a clinical response. The genetic associations were tested using logistic regression analyses. Neither polymorphism studied was found to be independently associated with response to clozapine. However, a statistically significant gene-gene interaction was observed between the polymorphisms. Participants with the COMT Val/Met or Met/Met genotype, who also had one or two DRD4 120-bp alleles (120/240 and 120/120), showed significantly better clinical response to clozapine. Our results highlight the importance of investigating gene-gene interactions, while studying the pharmacogenetics of clozapine.


Assuntos
Catecol O-Metiltransferase/genética , Clozapina/administração & dosagem , Resistência a Medicamentos , Receptores de Dopamina D4/genética , Esquizofrenia/tratamento farmacológico , Adulto , Substituição de Aminoácidos , Duplicação Cromossômica , Clozapina/farmacologia , Resistência a Medicamentos/efeitos dos fármacos , Epistasia Genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Variantes Farmacogenômicos , Esquizofrenia/genética , Resultado do Tratamento
4.
Biochim Biophys Acta Gen Subj ; 1862(9): 1870-1882, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29859963

RESUMO

BACKGROUND: An iron-overloaded state has been reported to be associated with insulin resistance. On the other hand, conditions such as classical hemochromatosis (where iron overload occurs primarily in the liver) have been reported to be associated with increased insulin sensitivity. The reasons for these contradictory findings are unclear. In this context, the effects of increased intracellular iron per se on insulin signaling in hepatocytes are not known. METHODS: Mouse primary hepatocytes were loaded with iron in vitro by incubation with ferric ammonium citrate (FAC). Intracellular events related to insulin signaling, as well as changes in gene expression and hepatocyte glucose production (HGP), were studied in the presence and absence of insulin and/or forskolin (a glucagon mimetic). RESULTS: In vitro iron-loading of hepatocytes resulted in phosphorylation-mediated activation of Akt and AMP-activated protein kinase. This was associated with decreased basal and forskolin-stimulated HGP. Iron attenuated forskolin-mediated induction of the key gluconeogenic enzyme, glucose-6-phosphatase. It also attenuated activation of the Akt pathway in response to insulin, which was associated with decreased protein levels of insulin receptor substrates 1 and 2, constituting insulin resistance. CONCLUSIONS: Increased intracellular iron has dual effects on insulin sensitivity in hepatocytes. It increased basal activation of the Akt pathway, but decreased activation of this pathway in response to insulin. GENERAL SIGNIFICANCE: These findings may help explain why both insulin resistance and increased sensitivity have been observed in iron-overloaded states. They are of relevance to a variety of disease conditions characterized by hepatic iron overload and increased risk of diabetes.


Assuntos
Regulação da Expressão Gênica/efeitos dos fármacos , Hepatócitos/metabolismo , Insulina/farmacologia , Sobrecarga de Ferro/fisiopatologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Animais , Células Cultivadas , Hepatócitos/efeitos dos fármacos , Hepatócitos/patologia , Hipoglicemiantes/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais/efeitos dos fármacos
5.
Br J Nutr ; 115(11): 1978-86, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27080262

RESUMO

Hepatic Fe overload has often been reported in patients with advanced alcoholic liver disease. However, it is not known clearly whether it is the effect of alcohol that is responsible for such overload. To address this lacuna, a time-course study was carried out in mice in order to determine the effect of alcohol on Fe homoeostasis. Male Swiss albino mice were pair-fed Lieber-DeCarli alcohol diet (20 % of total energy provided as alcohol) for 2, 4, 8 or 12 weeks. Expression levels of duodenal and hepatic Fe-related proteins were determined by quantitative PCR and Western blotting, as were Fe levels and parameters of oxidative stress in the liver. Alcohol induced cytochrome P4502E1 and oxidative stress in the liver. Hepatic Fe levels and ferritin protein expression dropped to significantly lower levels after 12 weeks of alcohol feeding, with no significant effects at earlier time points. This was associated, at 12 weeks, with significantly decreased liver hepcidin expression and serum hepcidin levels. Protein expressions of duodenal ferroportin (at 8 and 12 weeks) and divalent metal transporter 1 (at 8 weeks) were increased. Serum Fe levels rose progressively to significantly higher levels at 12 weeks. Histopathological examination of the liver showed mild steatosis, but no stainable Fe in mice fed alcohol for up to 12 weeks. In summary, alcohol ingestion by mice in this study affected several Fe-related parameters, but produced no hepatic Fe accumulation. On the contrary, alcohol-induced decreases in hepatic Fe levels were seen and may contribute to alcohol-induced suppression of hepcidin.


Assuntos
Etanol/efeitos adversos , Hepcidinas/metabolismo , Ferro/metabolismo , Hepatopatias Alcoólicas/metabolismo , Fígado/metabolismo , Animais , Proteínas de Transporte de Cátions/metabolismo , Duodeno/metabolismo , Fígado Gorduroso , Ferritinas/metabolismo , Hepcidinas/sangue , Ferro/sangue , Sobrecarga de Ferro/sangue , Fígado/patologia , Hepatopatias Alcoólicas/patologia , Masculino , Camundongos , Estresse Oxidativo
6.
Br J Haematol ; 164(4): 586-96, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24236640

RESUMO

ATOH8 has previously been shown to be an iron-regulated transcription factor, however its role in iron metabolism is not known. ATOH8 expression in HEK293 cells resulted in increased endogenous HAMP mRNA levels as well as HAMP promoter activity. Mutation of the E-box or SMAD response elements within the HAMP promoter significantly reduced the effects of ATOH8, indicating that ATOH8 activates HAMP transcription directly as well as through bone morphogenic protein (BMP) signalling. In support of the former, Chromatin immunoprecipitation assays provided evidence that ATOH8 binds to E-box regions within the HAMP promoter while the latter was supported by the finding that ATOH8 expression in HEK293 cells led to increased phosphorylated SMAD1,5,8 levels. Liver Atoh8 levels were reduced in mice under conditions associated with increased erythropoietic activity such as hypoxia, haemolytic anaemia, hypotransferrinaemia and erythropoietin treatment and increased by inhibitors of erythropoiesis. Hepatic Atoh8 mRNA levels increased in mice treated with holo transferrin, suggesting that Atoh8 responds to changes in plasma iron. ATOH8 is therefore a novel transcriptional regulator of HAMP, which is responsive to changes in plasma iron and erythroid activity and could explain how changes in erythroid activity lead to regulation of HAMP.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Eritropoese/genética , Eritropoese/fisiologia , Hepcidinas/genética , Proteínas Smad/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Feminino , Células HEK293 , Hepcidinas/biossíntese , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Regiões Promotoras Genéticas , Proteínas Smad/genética , Transcrição Gênica
7.
Br J Nutr ; 111(6): 1059-68, 2014 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-24160450

RESUMO

Mechanisms responsible for derangements in Fe homeostasis in chronic inflammatory conditions are not entirely clear. The aim of the present study was to test the hypothesis that inflammation affects the expression of Fe-related proteins in the duodenum and monocytes of patients with chronic inflammatory disorders, thus contributing to dysregulated Fe homeostasis. Duodenal mucosal samples and peripheral blood monocytes obtained from patients with chronic inflammatory disorders, namely ulcerative colitis (UC), Crohn's disease (CD) and rheumatoid arthritis, were used for gene and protein expression studies. Hb levels were significantly lower and serum C-reactive protein levels were significantly higher in patients in the disease groups. The gene expression of several Fe-related proteins in the duodenum was significantly up-regulated in patients with UC and CD. In patients with UC, the protein expression of divalent metal transporter 1 and ferroportin, which are involved in the absorption of dietary non-haem Fe, was also found to be significantly higher in the duodenal mucosa. The gene expression of the duodenal proteins of interest correlated positively with one another and negatively with Hb. In patients with UC, the gene expression of Fe-related proteins in monocytes was found to be unaffected. In a separate group of patients with UC, serum hepcidin levels were found to be significantly lower than those in the control group. In conclusion, the expression of Fe-related proteins was up-regulated in the duodenum of patients with chronic inflammatory conditions in the present study. The effects appeared to be secondary to anaemia and the consequent erythropoietic drive.


Assuntos
Artrite Reumatoide/metabolismo , Duodeno/metabolismo , Expressão Gênica , Doenças Inflamatórias Intestinais/metabolismo , Ferro/metabolismo , Regulação para Cima , Adulto , Idoso , Proteína C-Reativa/análise , Colite Ulcerativa/metabolismo , Doença de Crohn/metabolismo , Feminino , Ferritinas/sangue , Ferritinas/genética , Hemoglobinas/análise , Hepcidinas/sangue , Humanos , Ferro/sangue , Proteínas de Ligação ao Ferro/genética , Masculino , Pessoa de Meia-Idade , Monócitos/metabolismo
8.
J Biol Chem ; 287(6): 4099-106, 2012 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-22144676

RESUMO

The BMP/SMAD4 pathway has major effects on liver hepcidin levels. Bone morphogenetic protein-binding endothelial cell precursor-derived regulator (Bmper), a known regulator of BMP signaling, was found to be overexpressed at the mRNA and protein levels in liver of genetically hypotransferrinemic mice (Trf(hpx/hpx)). Soluble BMPER peptide inhibited BMP2- and BMP6-dependent hepcidin promoter activity in both HepG2 and HuH7 cells. These effects correlated with reduced cellular levels of pSMAD1/5/8. Addition of BMPER peptide to primary human hepatocytes abolished the BMP2-dependent increase in hepcidin mRNA, whereas injection of Bmper peptide into mice resulted in reduced liver hepcidin and increased serum iron levels. Thus Bmper may play an important role in suppressing hepcidin production in hypotransferrinemic mice.


Assuntos
Peptídeos Catiônicos Antimicrobianos/sangue , Proteínas de Transporte/metabolismo , Ferro/sangue , Fígado/metabolismo , Transferrina/metabolismo , Regulação para Cima , Animais , Peptídeos Catiônicos Antimicrobianos/genética , Proteína Morfogenética Óssea 2/antagonistas & inibidores , Proteína Morfogenética Óssea 2/genética , Proteína Morfogenética Óssea 2/metabolismo , Proteínas de Transporte/genética , Células Hep G2 , Hepcidinas , Humanos , Camundongos , Camundongos Transgênicos , Peptídeos/farmacologia , Proteínas Smad/genética , Proteínas Smad/metabolismo , Transferrina/genética
9.
Inflammation ; 46(6): 2209-2222, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37486527

RESUMO

Ulcerative colitis (UC) is often associated with anemia. Hepcidin, the central regulator of iron homeostasis, is known to be induced by inflammation and suppressed by anemia. It is not clear how hepcidin is affected in those with UC, when both inflammation and anemia may co-exist.Such knowledge may hold implications for treatment. Hematological and iron-related parameters, C-reactive protein (CRP), growth differentiation factor 15 (GDF-15) and erythroferrone (ERFE) (erythroid regulators of hepcidin) levels were estimated in blood from those with UC and in control subjects. Values for hematological and iron-related parameters showed evidence of iron-deficiency and resultant anemia, in patients with UC. The presence of UC was significantly associated with inflammation. Serum levels of ERFE, but not of GDF-15, were significantly higher in patients with UC than in control patients, while hepcidin levels were significantly lower. Serum hepcidin concentrations in patients with UC correlated positively with serum iron, ferritin and GDF-15, and negatively with serum ERFE. The iron status and serum hepcidin levels in UC patients with co-existent anemia were significantly lower and serum ERFE values significantly higher than in those with UC without anemia. The effect of anemia on hepcidin predominated over that of inflammation in patients with UC, resulting in suppressed hepcidin levels. This effect is possibly mediated through erythroferrone. We suggest that a serum hepcidin-guided approach may be useful to guide use of oral iron supplements to treat co-existent iron-deficiency anemia in patients with UC and other chronic inflammatory diseases.


Assuntos
Anemia Ferropriva , Anemia , Colite Ulcerativa , Humanos , Hepcidinas/metabolismo , Anemia Ferropriva/tratamento farmacológico , Anemia Ferropriva/complicações , Colite Ulcerativa/complicações , Colite Ulcerativa/tratamento farmacológico , Fator 15 de Diferenciação de Crescimento , Anemia/complicações , Anemia/metabolismo , Ferro/uso terapêutico , Ferro/metabolismo , Inflamação/complicações
10.
J Nutr Biochem ; 111: 109175, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36223834

RESUMO

Increased body iron stores and inflammation in adipose tissue have been implicated in the pathogenesis of insulin resistance (IR) and type 2 diabetes mellitus. However, the underlying basis of these associations is unclear. To attempt to investigate this, we studied the development of IR and associated inflammation in adipose tissue in the presence of increased body iron stores. Male hepcidin knock-out (Hamp1-/-) mice, which have increased body iron stores, and wild-type (WT) mice were fed a high-fat diet (HFD) for 12 and 24 weeks. Development of IR and metabolic parameters linked to this, insulin signaling in various tissues, and inflammation and iron-related parameters in visceral adipose tissue were studied in these animals. HFD-feeding resulted in impaired glucose tolerance in both genotypes of mice. In response to the HFD for 24 weeks, Hamp1-/- mice gained less body weight and developed less systemic IR than corresponding WT mice. This was associated with less lipid accumulation in the liver and decreased inflammation and lipolysis in the adipose tissue in the knock-out mice, than in the WT animals. Fewer macrophages infiltrated the adipose tissue in the knockout mice than in wild-type mice, with these macrophages exhibiting a predominantly anti-inflammatory (M2-like) phenotype and indirect evidence of a possible lowered intracellular iron content. The absence of hepcidin was thus associated with attenuated inflammation in the adipose tissue and increased whole-body insulin sensitivity, suggesting a role for it in these processes.


Assuntos
Diabetes Mellitus Tipo 2 , Resistência à Insulina , Masculino , Camundongos , Animais , Resistência à Insulina/fisiologia , Dieta Hiperlipídica/efeitos adversos , Hepcidinas/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Camundongos Endogâmicos C57BL , Tecido Adiposo/metabolismo , Inflamação/metabolismo , Insulina/metabolismo , Camundongos Knockout , Ferro/metabolismo
11.
Blood Cells Mol Dis ; 49(1): 11-9, 2012 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-22504041

RESUMO

Anemia of inflammation is characterized by disturbances in systemic iron homeostasis. In order to better understand the events involved, we carried out a time-course study on the effects of acute and chronic inflammation on iron-related proteins in mouse splenic macrophages and the liver. Mice were sacrificed at various time points ranging from 0 h up to 4 weeks after induction of inflammation with turpentine oil. Expression levels of iron-related proteins in the splenic macrophages and liver were determined. Iron levels in the serum, spleen and liver were also measured. Hepatic hepcidin was found to be induced in response to inflammation. In the macrophages, expression levels of ferroportin and TfR1 were decreased at some of the time points. The expression of hepatic TfR1 and ferritin was significantly higher at the early time points. Ferritin levels in the liver decreased progressively thereafter; this was associated with significantly higher ferroportin expression in the liver, despite high levels of hepcidin, suggesting that hepcidin may not regulate ferroportin levels in the liver, unlike in the macrophages. The effects of hepcidin, thus, appeared to be tissue-specific. Serum iron levels were decreased initially; these then rose and were associated with decreasing iron levels in the liver and spleen. Thus, inflammation affected the expression levels of many proteins involved in iron homeostasis in splenic macrophages and the liver, with differences seen in the effects at these 2 sites. These effects are likely to contribute to the development of anemia of inflammation.


Assuntos
Regulação da Expressão Gênica , Proteínas de Ligação ao Ferro/sangue , Ferro/sangue , Macrófagos/metabolismo , Baço/metabolismo , Anemia/sangue , Anemia/etiologia , Animais , Inflamação/sangue , Inflamação/induzido quimicamente , Inflamação/complicações , Irritantes/efeitos adversos , Irritantes/farmacologia , Fígado/metabolismo , Camundongos , Especificidade de Órgãos , Terebintina/efeitos adversos , Terebintina/farmacologia
12.
Br J Nutr ; 108(11): 1994-2001, 2012 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-22360813

RESUMO

In order to understand better the molecular mechanisms involved in the pathogenesis of anaemia of inflammation, we carried out a time-course study on the effects of turpentine-induced acute and chronic inflammation on duodenal proteins involved in Fe absorption in mice. Expression levels of these proteins and hepatic hepcidin and serum Fe levels were determined in inflamed mice. In acutely inflamed mice, significantly increased expression of ferritin was the earliest change observed, followed by decreased divalent metal transporter 1 expression in the duodenum and increased hepcidin expression in the liver. Ferroportin expression increased subsequently, despite high levels of hepcidin. Hypoferraemia, which developed at early time periods studied, was followed by increased serum Fe levels at later points. The present results thus show that acute inflammation induced several changes in the expression of proteins involved in duodenal Fe absorption, contributing to the development of hypoferraemia. Resolution of inflammation caused attenuation of many of these effects. Effects in chronically inflamed mice were less consistent. The present results also suggest that inflammation-induced increases in ferritin appeared to override the effects of hepcidin on the expression levels of ferroportin in enterocytes.


Assuntos
Anemia Ferropriva/etiologia , Duodenite/metabolismo , Duodeno/metabolismo , Ferritinas/metabolismo , Absorção Intestinal , Mucosa Intestinal/metabolismo , Ferro da Dieta/metabolismo , Doença Aguda , Animais , Peptídeos Catiônicos Antimicrobianos/genética , Peptídeos Catiônicos Antimicrobianos/metabolismo , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Doença Crônica , Duodenite/sangue , Duodenite/imunologia , Duodenite/fisiopatologia , Duodeno/imunologia , Ferritinas/genética , Regulação da Expressão Gênica , Hepcidinas , Mucosa Intestinal/imunologia , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos , RNA Mensageiro/metabolismo , Fatores de Tempo
13.
BMC Med Educ ; 12: 21, 2012 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-22510159

RESUMO

BACKGROUND: E-learning resources (e-resources) have been widely used to facilitate self-directed learning among medical students. The Department of Biochemistry at Christian Medical College (CMC), Vellore, India, has made available e-resources to first-year medical students to supplement conventional lecture-based teaching in the subject. This study was designed to assess students' perceptions of the impact of these e-resources on various aspects of their learning in biochemistry. METHODS: Sixty first-year medical students were the subjects of this study. At the end of the one-year course in biochemistry, the students were administered a questionnaire that asked them to assess the impact of the e-resources on various aspects of their learning in biochemistry. RESULTS: Ninety-eight percent of students had used the e-resources provided to varying extents. Most of them found the e-resources provided useful and of a high quality. The majority of them used these resources to prepare for periodic formative and final summative assessments in the course. The use of these resources increased steadily as the academic year progressed. Students said that the extent to which they understood the subject (83%) and their ability to answer questions in assessments (86%) had improved as a result of using these resources. They also said that they found biochemistry interesting (73%) and felt motivated to study the subject (59%). CONCLUSIONS: We found that first-year medical students extensively used the e-resources in biochemistry that were provided. They perceived that these resources had made a positive impact on various aspects of their learning in biochemistry. We conclude that e-resources are a useful supplement to conventional lecture-based teaching in the medical curriculum.


Assuntos
Bioquímica/educação , Comportamento do Consumidor , Internet/estatística & dados numéricos , Estudantes de Medicina/psicologia , Acesso à Informação , Adolescente , Educação de Graduação em Medicina , Feminino , Humanos , Índia , Masculino , Adulto Jovem
14.
Indian J Med Ethics ; VII(3): 196-202, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35699293

RESUMO

Unmerited authorship in research papers is widely acknowledged to constitute research misconduct. In different contexts, it has been called "gift", "honorary", or "guest" authorship. Although several attempts have been made to address the issue, it remains a significant problem in research. In this paper, we discuss accepted criteria that qualify a person to be an author on a research publication and define what constitutes "gift authorship". We also look at the scenario in India and try to identify the circumstances that have fostered this practice in academia in the country. Finally, we discuss the adverse effects of this practice on the research enterprise as a whole, and possible remedial measures.


Assuntos
Autoria , Má Conduta Científica , Humanos , Índia , Boca , Editoração
15.
J Diabetes Complications ; 35(9): 107977, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34217587

RESUMO

AIM: Diabetes mellitus has been reported to be associated with increased serum levels of ferritin. The basis of this association is unclear. It is also not precisely known whether other iron-related parameters, including hepcidin (the central regulator of systemic iron homeostasis), are affected under these circumstances. This study attempted to determine this. METHODS: Adult men (normoglycemic or newly diagnosed with diabetes or pre-diabetes) were recruited. Anthropometric, metabolic, and hematological and iron-related parameters in blood were measured. Indices of insulin resistance (HOMA-IR) and pancreatic beta cell function (HOMA-ß) were calculated. RESULTS: Subjects in the 3 groups were similar in age, and anthropometric and hematological parameters. Serum ferritin and hepcidin levels were higher in diabetics, than in pre-diabetics and in control subjects. These elevations seen were not linked to the presence of inflammation. HOMA-IR was higher in diabetics, and HOMA-ß lower in diabetics and pre-diabetics, than in control subjects. HOMA-IR and serum ferritin were positively correlated with one another. CONCLUSION: Elevated levels of serum ferritin and hepcidin in newly diagnosed diabetics (but not pre-diabetics) indicate dysregulated iron homeostasis, with the former positively associated with insulin resistance in these patients.


Assuntos
Diabetes Mellitus , Ferro/sangue , Estado Pré-Diabético , Adulto , Diabetes Mellitus/diagnóstico , Ferritinas/sangue , Hepcidinas , Homeostase , Humanos , Resistência à Insulina , Masculino , Estado Pré-Diabético/complicações , Estado Pré-Diabético/diagnóstico
16.
Biochim Biophys Acta Mol Cell Res ; 1867(2): 118621, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31812496

RESUMO

BACKGROUND: Increased body iron stores have been implicated in the pathogenesis of diabetes mellitus. However, the molecular mechanisms involved are unclear. The liver plays a central role in homeostasis of iron and glucose in the body. Mice deficient in hepcidin (the central regulator of systemic iron homeostasis) (Hamp1-/- mice) accumulate iron in the liver in vivo. The effects of such iron loading on hepatic insulin signaling and glucose metabolism are not known. METHODS: Hepatocytes isolated from Hamp1-/- mice were studied for markers of insulin signaling (and its downstream effects), glucose production, expression of gluconeogenic and lipogenic enzymes, and markers of AMPK (AMP-activated protein kinase) activation and oxidative stress. These parameters were studied both in the absence and presence of insulin, and also with the use of an iron chelator. RESULTS: Akt in the insulin signaling pathway was found to be activated in the Hamp1-/- hepatocytes to a greater extent than wild-type (WT) cells, both under basal conditions and in response to insulin. Incubation of the Hamp1-/- hepatocytes with an iron chelator attenuated these effects. There was no evidence of oxidative stress or AMPK activation in the Hamp1-/- hepatocytes. Glucose production by these cells was similar to that by WT cells. Gene expression of key gluconeogenic enzymes was decreased in these cells. In addition, they showed evidence of increased lipogenesis. CONCLUSIONS: Hepatocytes from Hamp1-/- mice showed evidence of greater sensitivity to the effects of insulin than WT hepatocytes. This may explain the insulin-sensitive phenotype that has been reported in classical hemochromatosis.


Assuntos
Hepcidinas/genética , Insulina/metabolismo , Ferro/toxicidade , Transdução de Sinais/efeitos dos fármacos , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Células Cultivadas , Ferritinas/metabolismo , Glucose/metabolismo , Glucose-6-Fosfatase/metabolismo , Hepatócitos/citologia , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Hepcidinas/deficiência , Insulina/farmacologia , Ferro/metabolismo , Quelantes de Ferro/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Estresse Oxidativo/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores da Transferrina/genética , Receptores da Transferrina/metabolismo
17.
J Nutr Biochem ; 84: 108441, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32629238

RESUMO

Type 2 diabetes mellitus (T2DM) and insulin resistance (IR) have been associated with dysregulation of iron metabolism. The basis for this association is not completely understood. To attempt to investigate this, we studied temporal associations between onset of insulin resistance (IR) and dysregulated iron homeostasis, in a mouse model of T2DM. Male C57Bl/6 mice (aged 8 weeks) were fed a high-fat diet (HFD; 60% energy from fat) or a control diet (CD; 10% energy from fat) for 4, 8, 12, 16, 20 and 24 weeks. Development of IR was documented, and various metabolic, inflammatory and iron-related parameters were studied in these mice. HFD-feeding induced weight gain, hepato-steatosis and IR in the mice. Onset of IR occurred from 12 weeks onwards. Hepatic iron stores progressively declined from 16 weeks onwards. Accompanying changes included a decrease in hepatic hepcidin (Hamp1) mRNA expression and serum hepcidin levels and an increase in iron content in the epididymal white adipose tissue (eWAT). Iron content in the liver negatively correlated with that in the eWAT. Factors known to regulate hepatic Hamp1 expression (such as serum iron levels, systemic inflammation, and bone marrow-derived erythroid regulators) were not affected by HFD-feeding. In conclusion, the results show that the onset of IR in HFD-fed mice preceded dysregulation of iron homeostasis, evidence of which were found both in the liver and visceral adipose tissue.


Assuntos
Dieta Hiperlipídica/efeitos adversos , Resistência à Insulina , Insulina/metabolismo , Ferro/metabolismo , Tecido Adiposo/metabolismo , Animais , Diabetes Mellitus Tipo 2/metabolismo , Homeostase , Inflamação/metabolismo , Fígado/metabolismo , Masculino , Camundongos Endogâmicos C57BL
18.
J Trace Elem Med Biol ; 58: 126442, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31835128

RESUMO

BACKGROUND: Perturbations in iron homeostasis have been reported to be associated with irreversible liver injury in chronic liver disease (CLD). However, it is not clear whether liver dysfunction per se underlies such dysregulation or whether other factors also contribute to it. This study attempted to examine the issues involved. METHODS: Patients diagnosed to have chronic liver disease (n = 63), who underwent a medically-indicated upper gastrointestinal endoscopy, were the subjects of this study. Patients with dyspepsia, who underwent such a procedure, and were found to have no endoscopic abnormalities, were used as control subjects (n = 49). Duodenal mucosal samples were obtained to study mRNA and protein levels of duodenal proteins involved in iron absorption. A blood sample was also obtained for estimation of hematological, iron-related, inflammatory and liver function-related parameters. RESULTS: Patients with CLD had impaired liver function, anemia of inflammation and lower serum levels of hepcidin than control subjects. Gene (mRNA) expression levels of duodenal ferroportin and duodenal cytochrome b (proteins involved in iron absorption) were decreased, while that of divalent metal transporter-1 (DMT-1) was unchanged. Protein expression of DMT-1 was, however, decreased while that of ferroportin was unchanged. In the CLD group, serum hepcidin was predicted independently by serum ferritin and hemoglobin, but not by C-reactive protein (a marker of inflammation). CLD patients with serum ferritin greater than 300 µg/dL had significantly greater liver dysfunction (as indicated by significantly higher serum concentrations of bilirubin, AST and ALT, and MELD scores), higher serum concentrations of CRP and hepcidin, and higher ferroportin protein expression, than those with serum ferritin ≤ 300 µg/dL. CONCLUSIONS: In patients with CLD, anemia of inflammation and low serum hepcidin levels were found to paradoxically co-exist. Expression of duodenal proteins involved in iron absorption were either decreased or unaltered in these patients. The hepcidin response to higher body iron levels and/or inflammation appeared to be functional in these patients, despite the presence of liver disease.


Assuntos
Hepcidinas/metabolismo , Homeostase , Ferro/metabolismo , Hepatopatias/metabolismo , Biomarcadores/sangue , Proteína C-Reativa/metabolismo , Estudos de Casos e Controles , Doença Crônica , Duodeno/metabolismo , Ferritinas/sangue , Hepcidinas/sangue , Humanos , Absorção Intestinal , Hepatopatias/sangue , Hepatopatias/virologia , Masculino , Pessoa de Meia-Idade
19.
Crit Care Med ; 36(1): 172-5, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18007267

RESUMO

OBJECTIVE: Early neurologic deterioration has been studied in patients with intracerebral hemorrhage during hospitalization, but rates and factors associated with prehospital neurologic deterioration (PND) are unknown. We sought to determine the prevalence of PND among patients with intracerebral hemorrhage during Emergency Medical Services transportation to the hospital. DESIGN: Historical cohort study. SETTINGS: U.S. acute care hospital from 2000 to 2004. PATIENTS: Hospitalized patients with a diagnosis of spontaneous intracerebral hemorrhage were identified by codes of the International Statistical Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). METHODS: The initial Glasgow Coma Scale score ascertained at the scene by the Emergency Medical Services was compared with the subsequent evaluation in the emergency department to identify neurologic deterioration (defined as a decrease in Glasgow Coma Scale of > or = 2 points). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of the 98 patients with acute intracerebral hemorrhage, 22 patients (22%) showed PND during Emergency Medical Services transport, with a mean decrease in the Glasgow Coma Scale score during transport of 6 points. The patients who demonstrated neurologic deterioration tended to have higher diastolic blood pressure at the scene (p = .045), greater rates of intraventricular extension (p < .0001), and radiologic signs of herniation (p < .0001) on initial computed tomographic scan. There was a statistically significant decrease in diastolic blood pressure between the evaluations of the Emergency Medical Services and the emergency department among both patients with and without PND. CONCLUSIONS: PND occurs in nearly one fifth of patients with intracerebral hemorrhage. Higher diastolic blood pressure at the scene, intraventricular extension, and radiologically evident herniation seem to be associated with PND. Prospective studies are needed to evaluate the efficacy of Emergency Medical Services interventions to reduce this early clinical deterioration.


Assuntos
Hemorragia Cerebral/epidemiologia , Serviços Médicos de Emergência/estatística & dados numéricos , Doenças do Sistema Nervoso/epidemiologia , Distribuição por Idade , Hemorragia Cerebral/terapia , Estudos de Coortes , Feminino , Escala de Coma de Glasgow , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Doenças do Sistema Nervoso/diagnóstico , Doenças do Sistema Nervoso/terapia , New Jersey/epidemiologia , Prevalência , Estudos Retrospectivos , Análise de Sobrevida
20.
Clin Chim Acta ; 396(1-2): 23-5, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18619953

RESUMO

BACKGROUND: Myeloperoxidase (MPO) and interleukin-6 (IL-6) are often used as markers of inflammation. The aim of this study was to ascertain whether MPO activity is as reliable as IL-6 as an indicator of inflammation. METHODS: Inflammation was induced in mice, using either turpentine or indomethacin. Duodenal tissue was removed from these animals at various time periods ranging from 6 h to 7 days later. Concentrations of IL-6 and MPO activity were estimated in the tissue. Histopathological examination was also carried out at some of the time periods to determine the presence of neutrophil infiltration in turpentine-treated mice. RESULTS: Concentrations of IL-6 and MPO activity were significantly higher in tissue that had been treated with the agents used, at all the time periods studied, when compared with corresponding control tissue. Fold-increases in MPO activity were higher than fold-increases in IL-6. Concentrations of the 2 parameters showed significant positive correlation. Histopathological examination did not show significantly higher numbers of neutrophils infiltrating the tissue in response to turpentine, at the time periods studied. CONCLUSIONS: Estimation of MPO activity is a reliable indicator of inflammation, being more sensitive than histopathological examination of tissue and as good as measurement of IL-6 concentrations.


Assuntos
Peroxidase/metabolismo , Animais , Indometacina/uso terapêutico , Inflamação/tratamento farmacológico , Inflamação/enzimologia , Interleucina-6/metabolismo , Masculino , Camundongos , Terebintina/uso terapêutico
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