Hypertrophied myocardium is more dependent on extracellular calcium than the normal cardiac muscle.

BACKGROUND: The aim of this study was to analyze stable hypertrophied myocardial function and its response to inotropic maneuvers in rats submitted to renovascular hypertension for a 10-week period (RHT group, n=10). MATERIAL/METHODS: Myocardial performance was studied in isolated left ventricle papillary muscles in isometric contraction under the following conditions: at postrest contraction of 30 seconds (PRC), at extracellular calcium (ECa2+) chloride concentration of 1.25 and 5.20 mM, and after beta-adrenergic stimulation with 10-6 M isoproterenol (ISOP). RESULTS: The results were compared with normotensive Wistar controls rats (C group, n=10). In basal condition, resting tension, and contraction time (TPT) were greater, while relaxation time (RT50) tended to be longer in RHT than C group. PRC and ISOP promoted a similar change in muscle function response intensity (delta) in both groups. ECa2+ shift did not change TPT in the C group and decreased TPT in the RHT animals; delta was different between these groups. RT50 increased in C and decreased in RHT, both without statistical significance; however, delta was different. CONCLUSIONS: These results suggest that hypertrophied myocardial dysfunction may be attributed to changes in intracellular calcium cycling.

A comparative study of myocardial function and morphology during fasting/refeeding and food restriction in rats.

BACKGROUND: This study compared the influence of fasting/refeeding cycles and food restriction on rat myocardial performance and morphology. METHODS: Sixty-day-old male Wistar rats were submitted to food ad libitum (C), 50% food restriction (R50), and fasting/refeeding cycles (RF) for 12 weeks. Myocardial function was evaluated under baseline conditions and after progressive increase in calcium and isoproterenol. Myocardium ultrastructure was examined in the papillary muscle. RESULTS: Fasting/refeeding cycles maintained rat body weight and left ventricle weight between control and food-restricted rats. Under baseline conditions, the time to peak tension (TPT) was more prolonged in R50 than in RF and C rats. Furthermore, the maximum tension decline rate (-dT/dt) increased less in R50 than in RF with calcium elevation. While the R50 group showed focal changes in many muscle fibers, such as the disorganization or loss of myofilaments, polymorphic mitochondria with disrupted cristae, and irregular appearance or infolding of the plasma membrane, the RF rats displayed few alterations such as loss or disorganization of myofibrils. CONCLUSION: Food restriction promotes myocardial dysfunction, not observed in RF rats, and higher morphological damage than with fasting/refeeding. The increase in TPT may be attributed possibly to the disorganization and loss of myofibrils; however, the mechanisms responsible for the alteration in -dT/dt in R50 needs to be further clarified.

Growth hormone attenuates myocardial fibrosis in rats with chronic pressure overload-induced left ventricular hypertrophy.

1. The role of growth hormone (GH) in cardiac remodelling and function in chronic and persistent pressure overload-induced left ventricular hypertrophy has not been defined. The aim of the present study was to assess short-term GH treatment on left ventricular function and remodelling in rats with chronic pressure overload-induced hypertrophy. 2. Twenty-six weeks after induction of ascending aortic stenosis (AAS), rats were treated with daily subcutaneous injections of recombinant human GH (1 mg/kg per day; AAS-GH group) or saline (AAS-P group) for 14 days. Sham-operated animals served as controls. Left ventricular function was assessed by echocardiography before and after GH treatment. Myocardial fibrosis was evaluated by histological analysis. 3. Before GH treatment, AAS rats presented similar left ventricular function and structure. Treatment of rats with GH after the AAS procedure did not change bodyweight or heart weight, both of which were higher in the AAS groups than in the controls. After GH treatment, posterior wall shortening velocity (PWSV) was lower in the AAS-P group than in the control group. However, in the AAS-GH group, PWSV was between that in the control and AAS-P groups and did not differ significantly from either group. Fractional collagen (% of total area) was significantly higher in the AAS-P and AAS-GH groups compared with control (10.34 +/- 1.29, 4.44 +/- 1.37 and 1.88 +/- 0.88%, respectively; P < 0.05) and was higher still in the AAS-P group compared with the AAS-GH group. 4. The present study has shown that short-term administration of GH to rats with chronic pressure overload-induced left ventricular hypertrophy induces cardioprotection by attenuating myocardial fibrosis.

O efeito do exercício em mini-trampolim de solo sobre medidas de resistência muscular localizada (RML), capacidade aeróbia (VO2) e flexibilidade / Effects of rebound exercise training on some variables with located muscular strength, aerobic capability and flexibility

O presente estudo teve como objetivo analisar os efeitos de um programa de dezesseis semanas em mini-trampolim de solo sobre resistência muscular localizada “RML” de membros inferiores e abdominal, flexibilidade e capacidade aeróbia, em mulheres sedentárias entre 20 e 35 anos de idade. Trata-se de ensaio de intervenção em 26 voluntárias, aplicado em três sessões semanais de quarenta e cinco minutos. Foram realizados os seguintes testes: 1) RML: por repetição máxima em 1 minuto, 2) Capacidade aeróbia (VO2): banco de Astrand, 3) flexibilidade: sentar e alcançar (banco de Wells). Para comparação dos dados antes e depois do treinamento, aplicou-se teste t de Student para amostras dependentes, utilizando-se pacote estatístico SPSS. Observou-se que o programa proporcionou aumentos significativos da flexibilidade, resistência muscular abdominal e de membros inferiores, além de melhora significativa na freqüência cardíaca de recuperação pós-exercício e no consumo máximo de oxigênio. Estes resultados indicam que o mini-trampolim de solo é atividade capaz de incrementar capacidades físicas importantes para manutenção da saúde.

The present study aimed to analyze the effects of a program of sixteen weeks on mini-trampoline ground on muscular endurance "RML" lower limb and abdominal, flexibility and aerobic capacity in sedentary women between 20 and 35 years old. It is intervention trial in 26 volunteers applied three times per week for forty-five minutes. 1) RML: The following tests were performed by repetition maximum in 1 minute, 2) Aerobic capacity (VO2): bank Astrand, 3) flexibility: sit and reach (Wells). to comparison of data before and after training, we applied the Student t test for samples dependent, using SPSS statistical package. It was noted that the program provided increases significant flexibility, abdominal muscle endurance and lower limbs, as well as improvement significant in heart rate recovery after exercise and maximal oxygen consumption. These results indicate that the mini trampoline is soil activity to increase capacity Physical important for health maintenance.

Food restriction impairs myocardial inotropic response to calcium and beta-adrenergic stimulation in spontaneously hypertensive rats.

Although long-term food restriction (FR) has been shown to induce cardiac remodeling and dysfunction, there are few data on the effects of FR on pressure-overloaded hearts. The aim of this study was to examine the effects of FR on cardiac muscle performance during inotropic stimulation in the myocardium of spontaneously hypertensive rats (SHRs). Male 60-day-old SHRs were subjected to FR for 90 days. Food-restricted animals received 50% of the ad libitum amount of food consumed by the control group. Myocardial function was studied in isolated left ventricular papillary muscle under isometric contraction in basal condition (1.25 mmol/L extracellular Ca(2+) concentration) and after 3 inotropic maneuvers: (1) at postrest contraction of 30 seconds, (2) at extracellular Ca(2+) concentration of 5.2 mmol/L, and (3) after beta-adrenergic stimulation with 10(-6) mol/L isoproterenol. At basal condition, time from peak tension to 50% relaxation was greater in the food-restricted group (P < .05). Inotropic stimulation with postrest contraction and isoproterenol promoted a significant lower increase of developed tension, maximum rate of tension development, and maximum rate of tension decline in the food-restricted compared to the control group. The elevation of extracellular Ca(2+) concentration induced a lower increase of developed tension, maximum rate of tension development, and time from peak tension to 50% relaxation in the food-restricted than in the control group. In conclusion, long-term FR promotes impairment of myocardial inotropic response to calcium and beta-adrenergic stimulation in SHRs.

Prevalência e implicações da incontinência urinária e fecal em mulheres / Prevalence and implications of urinary and fecal incontinence in women

Avaliar a prevalência da incontinência urinária (IU) e fecal em mulheres atendidas no ambulatório geral do Centro de Saúde Escola - Botucatu - SP. Foram escolhidas 807 mulheres aleatoriamente responderam um questionário aplicado por entrevistadores previamente selecionados e treinados, após assinarem termo de consentimento livre e esclarecido aprovado pelo CEP. Foram distribuídas em dois grupos: GI (n=567), mulheres sem perda de urina, e grupo G2 (n=240), com perda urinária. A média de idade no GI foi de 52 anos e no G2 de 51, não havendo diferença estatisticamente significativa entre os grupos. A prevalência de incontinência urinária foi de 29,7 porcento e em 59,2 porcento a urgência estava associada. O índice de massa corpórea (IMC) foi significativamente mais alto no grupo com perda de urina em relação às mulheres continentes. Na análise de outras variáveis não houve diferença estatisticamente significativa entre os grupos estudados. No grupo de mulheres incontinentes, observou-se número significativamente mais alto de partos vaginais nas mulheres com urgência e incontinência fecal em relação às continentes. A obesidade pode ser fator contributivo ou mesmo de piora da IU. A incontinência, seja urinária de urgência ou fecal, está relacionada a número mais alto de partos vaginais.

Our objective was to evaluate the prevalence of urinary incontinence in women seen at the general outpatient service of Health-School Unit of Botucatu - UNESP. 807 women answered a questionnaire applied by interviewers previously selected and trained, after signing a free informed consent approved by CEP. They were divided into 2 groups: GI (n=567) with women without urine loss and group G2 (n=240) with urine loss. Mean age in group GI was 52 years and 51 years in G2. There was no statistically significant diference between both groups. Urinary incontinence prevalence was 29.7 percent, and in 59.2 percent of cases urgency was associated. Body mass index (BMI) was significantly higher in the group with urine loss when compared to the continent women. By analyzing other variables there was no statistically significant difference between both groups. In the incontinent group, there was a significantly higher number of vaginal deliveries in women with urgency. Considering fecal loss, vaginal deliveries had a significantly higher number among incontinent than continent women. Obesity can either contribute of worsen urinary incontinence. Fecal or urge incontinence is related to the higher number of vaginal deliveries.

Influences of rich in saturated and unsaturated fatty acids diets in rat myocardium.

OBJECTIVES: To study the influence of saturated (SFA) and unsaturated fatty acid (UFA) rich diets on mechanical function, morphology and oxidative stress in rat myocardium. METHODS: Male, 60-day-old Wistar rats were fed a control (n=8), a SFA (n=8), or a UFA-rich diet (n=8) for sixty days. Mechanical function was studied in isolated left ventricle papillary muscle under isometric and isotonic contractions, in basal conditions (1.25 mM calcium chloride) and after 5.2 mM calcium chloride and beta-adrenergic stimuli with 1.0 microM isoproterenol. Left ventricle fragments were used to study oxidative stress and morphology under light and electron microscopy. RESULTS: SFA and UFA-rich diets did not change myocardium mechanical function. Both diets caused oxidative stress, with high lipid hydroperoxide and low superoxide-dismutase concentrations. UFA rich diet decreased catalase expression and SFA rich diet decreased the amount of myocardial glutathione-peroxidase. Both diets promoted light ultrastructural injuries such as lipid deposits and cell membrane injuries. CONCLUSION: Results suggest that SFA and UFA rich diets do not alter isolated muscle mechanical function, but promote light myocardial morphological injuries and oxidative stress.

Influências de dietas ricas em ácidos graxos saturados e insaturados sobre o miocárdio de ratos / Influences of rich in saturated and unsaturated fatty acids diets in rat myocardium

OBJETIVOS: O estudo avaliou a influência de dietas ricas em ácidos graxos saturados (AGS) e ácidos graxos insaturados (AGI) sobre a função mecânica, a morfologia e o estresse oxidativo do miocárdio de ratos. MÉTODOS: Ratos Wistar com 60 dias de idade foram alimentados com dieta padrão (n = 8) ou dietas ricas em AGS (n = 8) ou AGI (n = 8) durante 60 dias. A função mecânica foi avaliada em músculo papilar isolado do ventrículo esquerdo (VE) por meio de contrações isométrica e isotônica, em condição basal (1,25 mM de cálcio), após elevação da concentração extracelular de cálcio para 5,2 mM e estimulação beta-adrenérgica com isoproterenol 1,0 µM. Fragmentos do VE foram usados para estudo de estresse oxidativo e microscopias óptica e eletrônica. RESULTADOS: As dietas suplementadas com AGS e AGI não alteraram a função mecânica do músculo cardíaco. Entretanto, ambas provocaram estresse oxidativo, com aumento do hidroperóxido de lipídio e redução da concentração de superóxido dismutase. A dieta AGI diminuiu a expressão da catalase e a AGS reduziu a quantidade de glutationa peroxidase miocárdica. Ambas as dietas promoveram discretas alterações morfológicas visualizadas ultra-estruturalmente, como depósitos lipídicos e lesões das membranas celulares. CONCLUSÃO: Os resultados sugerem que dietas enriquecidas com AGS e AGI não acarretam alteração da função mecânica do músculo cardíaco isolado, mas causam discretas lesões estruturais e estresse oxidativo no miocárdio.

OBJECTIVES: To study the influence of saturated (SFA) and unsaturated fatty acid (UFA) rich diets on mechanical function, morphology and oxidative stress in rat myocardium. METHODS: Male, 60-day-old Wistar rats were fed a control (n=8), a SFA (n=8), or a UFA-rich diet (n=8) for sixty days. Mechanical function was studied in isolated left ventricle papillary muscle under isometric and isotonic contractions, in basal conditions (1.25mM calcium chloride) and after 5.2mM calcium chloride and beta-adrenergic stimuli with 1.0µM isoproterenol. Left ventricle fragments were used to study oxidative stress and morphology under light and electron microscopy. RESULTS: SFA and UFA-rich diets did not change myocardium mechanical function. Both diets caused oxidative stress, with high lipid hydroperoxide and low superoxide-dismutase concentrations. UFA rich diet decreased catalase expression and SFA rich diet decreased the amount of myocardial glutathione-peroxidase. Both diets promoted light ultrastructural injuries such as lipid deposits and cell membrane injuries. CONCLUSION: Results suggest that SFA and UFA rich diets do not alter isolated muscle mechanical function, but promote light myocardial morphological injuries and oxidative stress.

Mensuração do tamanho cardíaco em radiografias de gatos com hipertireoidismo experimental / Vertebral scale system to measure heart size in radiographs in experimentally hyperthyroidism in the cats

O hipertireoidismo felino ou tireotoxicose é a doença endócrina mais freqüente em gatos domésticos. O hipertireoidismo felino é uma desordem multissistêmica associada com aumento das concentrações dos hormônios tireoidianos circulantes, triidotironina (T3) e tiroxina (T4). Anormalidades cardiovasculares em gatos com hipertireoidismo espontâneo já foram bem descritas. O objetivo deste trabalho foi realizar a mensuração cardíaca em 19 gatos submetidos a tireotoxicose experimental, utilizando o “vertebral heart size” (VHS). A mensuração utilizando o VHS foi realizada a partir de radiografias torácicas lateral, dorsoventral e ventrodorsal. As radiografias torácicas laterais foram mais eficazes do que as ventrodorsal e dorsoventral em ilustrar o aumento progressivo do coração. O VHS é um método fácil de ser usado, permitindo a avaliação do tamanho cardíaco em gatos hipertireóideos, e facilita a identificação de cardiomegalia e progressão do tamanho cardíaco.

Feline hyperthyroidism (thyrotoxicosis) is now recognised as the most common endocrine disease of the domestic cat. Feline hyperthyroidism cause multisystemic disorder associated with incresead circulating concentrations of the thyroid hormones, tri-iodothyronine (T3) and thyroxine (T4). Cardiovascular abnormalities in cats with spontaneous hyperthyroid have been described. Objective to determine heart size of progressing experimental thyrotoxicosis of 19 cats, using a vertebral scale system (VHS). The lateral, dorsoventral e ventrodorsal radiographs thoracic were measured using a vertebral scale system. Lateral radiographs thoracic to efficient develop that DV and VD. The VHS method is easy to use, allows objective assessment of heart size in cats hyperthyroid, and may be helpful to identify cardiomegaly and heart size progressing.

Agravos músculo-esqueléticos em bailarinas clássicas, não clássicas e praticantes de educação física / Musculoskeletal injuries in classical and non-classical ballerinas, and people who practice physical education: a comparative study

A literatura especializada descreve grande número de agravos que são típicos das praticantes de dança compredominância das lesões nos membros inferiores. No entanto, em nosso meio, pouco se conhece sobre oimpacto da exposição das bailarinas a esses processos mórbidos. O objetivo da presente investigaçãobuscou observar a ocorrência de Agravos Músculos-Esqueléticos (AME) em praticantes de balé e embailarinas sem formação clássica, comparando-as com escolares participantes apenas de aulas de EducaçãoFísica. Para tanto, realizou-se um estudo na cidade de Bauru - SP com 83 jovens de 12 a 17 anos dispostas emtrês grupos, a saber: i) bailarinas clássicas (27); ii) praticantes de dança sem formação clássica (19) e iii)alunas que participavam apenas de aulas escolares de Educação Física (37). A investigação ocorreu noperíodo de 225 dias, sendo que, por quinzena, cada participante foi entrevistada e as informações registradasem formulário específico. Os números médios de dias com AME nos grupos considerados foram de 42,16+59,09nas escolares, 181,80+118,65 para as bailarinas clássicas e 36,32+ 61,71 para às não-clássicas. Entre asbailarinas clássicas, 24 (89%) relataram agravos, as quais passaram, em média, 81% dos dias do período deacompanhamento com manifestações dolorosas. As bailarinas clássicas e não clássicas apresentarammovimentos de flexão como a causa situacional que mais resulta em AME. Entre as escolares os movimentosde força muscular são responsáveis por grande parte dos AME. Entre os grupos a região corporal que maisse destaca com relação a presença de AME é o joelho, com predominância de intensidade moderada. Oelevado número de dias que as bailarinas clássicas referiram queixas de dor pode estar relacionado commovimentos repetitivos resultantes de microtraumas na ultra estrutura de músculos, tendões e ligamentosque indicam o caráter crônico dos agravos.

The technical literature describes a large number of disorders typical of people who practice dance withpredominance of lower extremities injuries. Nevertheless, there is a little knowledge about the impact of theexposure of ballerinas to these morbid processes. The aim of this investigation was to observe the occurrenceof musculoskeletal injuries in ballet dancers and ballerinas with no classical formation comparing them toschool dancers, which only practice it in their physical education classes. To accomplish that, a study wascarried out in Bauru, São Paulo, Brazil, with 83 youths aging from 12 to 17 years old and divided into threegroups as follow: i) classic ballerinas (27); ii) dancers without classical formation (19) and iii) students thatparticipate in regular P.E classes (37). The evaluation was accomplished in 225 days. Each participant wasinterviewed in an interval of fifteen days and an appropriated formulary was filled to register the information.The average of days with musculoskeletal injuries in the considered groups was 42.16 + 59.09 into studentsgroup, 181.80 + 118.65 to classical ballerinas group, and 36.32 + 61.71 to non-classical ballerinas group. Amongclassical ballerinas 24 (89%) presented injuries and spend approximately 81% of the attendance days with painfulmanifestation. The classical and non-classical ballerinas presented movements with flexion as the situationalcause, which mostly results in MSI. Among the schoolgirls the movement of muscular strength is responsible formost part of MSI. Among these groups the body region where the MSI is easily recognized, with predominanceand in moderate intensity, is the knee. The high number of days in which the classical ballerinas mentioned to befeeling pain can be related to the repetitive movements resulting from micro traumas in the ultra structure of themuscles, tendons, and ligaments that indicate the chronic aspect of the injuries.

Correlação entre qualidade de vida de mulheres obesas e a prática do Deep Water Running pela análise canônica / Correlation between quality of life and deep water running in obese women through canonic analysis

Objetivo: Investigar a correlação entre mudanças de aptidão física e qualidade de vida em obesas através do deep water running em intervenção de 17 semanas (três sessões semanais), sem dieta específica. Métodos: Estudo quase-experimental de grupo único, com avaliação inicial e final. Avaliaram-se 31 mulheres (38 a 57 anos) com 30 a 40% de gordura. Consideraram-se percentual de gordura, circunferências, condição cardiorrespiratória, flexibilidade, força e qualidade de vida. Aplicaram-se, com5% de significância, o teste “t” de Student, teste não-paramétrico de Wilcoxon e análise canônica para associação entre qualidade de vida e aptidão física. ResultadosConstatou-se melhora da condição cardiorrespiratória (p<0,001), da força(p<0,001), da flexibilidade (p<0,001), redução da gordura corporal (p<0,001),aumento da massa muscular (p<0,001) e evolução da qualidade de vida nosdomínios físico (p<0,001), psicológico (p<0,001) e das relações sociais (p<0,005). O valor de 0,83 (p<0,01) da análise canônica apontou correlação significante entre qualidade de vida e aptidão física. Conclusão:Observou-se o efeito singular do deep water running, indicando que este tipo deexercícios físicos pode efetivamente beneficiar a evolução da qualidade de vida de obesas

[Echocardiographic criteria for the definition of ventricular dysfunction severity in aortic banded rats]. / Critérios ecocardiográficos para definição de graus de disfunção ventricular em ratos portadores de estenose aórtica.

OBJECTIVE: The purpose of this study was to identify echocardiographic parameters that allow distinguishing different levels of cardiac dysfunction in aortic banded rats. METHODS: Wistar male rats (90-100 g) were subjected to aortic banding (n=23) or a sham operation (n=12). The following echocardiographic parameters were evaluated and used to group rats into groups with similar characteristics using cluster analysis: absolute values and after normalization to body weight of left ventricular end-diastolic diameter (LVDD) and left atrial systolic diameter; left ventricular end-systolic diameter (LVSD); LV weight to body weight ratio (LVW/BW); three indexes of left ventricular shortening (endocardial fractional shortening, EFS; midwall FS, MFS; and posterior wall shortening velocity, (PWSV). RESULTS: The cluster analysis could group aortic banded rats into two groups: mild (n=13) and severe (n=9) stage of heart failure. There was no overlapping among the values of the 95% confidence interval of the following parameters between the two groups: LVDD, LVSD, EFS, MFS, LVW/BW, and PWSV. CONCLUSION: It is feasible to distinguish two groups of aortic banded rats according to the level of cardiac dysfunction using those echocardiographic parameters. This allows to perform longitudinal studies in homogeneous groups of rats with aortic banding and cardiac dysfunction.

Critérios ecocardiográficos para definição de graus de disfunção ventricular em ratos portadores de estenose aórtica / Echocardiographic criteria for the definition of ventricular dysfunction severity in aortic banded rats

OBJETIVO: O objetivo deste estudo foi identificar variáveis ecocardiográficas que definam graus de disfunção cardíaca em ratos com estenose aórtica (EAo). MÉTODOS: Ratos Wistar (n = 23), machos (90-100 g), foram submetidos a cirurgia para indução de EAo. As variáveis ecocardiográficas analisadas foram: diâmetros diastólico do ventrículo esquerdo (DDVE) e sistólico do átrio esquerdo em valores absolutos e normalizados para o peso corporal; diâmetro sistólico do VE (DSVE); três índices de encurtamento do VE ( por cento de encurtamento endocárdico, por centoEnc.Endo; por cento de encurtamento miocárdico, por centoEnc.Mio; e velocidade de encurtamento da parede posterior do VE, VEPP); e índice de massa do VE (IMVE). Essas variáveis foram utilizadas para a análise de agrupamento ("cluster analysis"). RESULTADOS: A análise de agrupamento possibilitou separar os ratos com EAo em dois grupos: disfunção leve (n = 13) e disfunção severa (n = 9). Os intervalos de confiança das seguintes variáveis não apresentaram superposição dos seus valores: DDVE, DSVE, por centoEnc.Endo, por centoEnc.Mio, IMVE e VEPP. CONCLUSÃO: A utilização conjunta dos intervalos de confiança dessas variáveis permite identificar dois grupos de ratos com estenose aórtica e diferentes graus de comprometimento cardíaco, possibilitando a realização de estudos longitudinais com grupos homogêneos de animais.

Daytime variations in glucose tolerance in people with impaired glucose tolerance.

To determine whether glucose tolerance varies throughout the day in people with impaired glucose tolerance (IGT). We studied 15 healthy IGT, and 18 matched normal glucose tolerant (NGT) individuals. Blood samples were taken every 30-120 min during a 24h period in which all individuals had three mixed meals and nocturnal sleep. We measured glucose, free fatty acids, specific insulin, intact proinsulin, cortisol and growth hormone. Variable responses were considered as concentrations and areas under the curves. Comparison between the groups was by Student's t-test, Mann-Whitney, and analysis of variance. Higher total glucose response, inappropriate normal total insulin response, and unproportionally increased proinsulin total response were observed in the IGT group. Lower glucose tolerance occurred in IGT after dinner, as in the NGT, and after breakfast associated with increased insulin response after breakfast, and similar proinsulin response after all three meals. IGT had higher glucose response than NGT after breakfast and lunch, similar insulin responses, and increased proinsulin-insulin ratio after all three meals. Data from this study demonstrate that IGT individuals present lower glucose tolerance in the evening, as those with NGT, and in the morning, as reported in patients with type 2 diabetes.

[Contribution of post-breakfast plasma glucose to the glycemic control of type 2 diabetic patients]. / Contribuição da glicemia pós-desjejum para o controle glicêmico do paciente com diabetes melito tipo 2.

UNLABELLED: Epidemiological studies have documented that postprandial hyperglycemia is the main risk factor for cardiovascular diseases. It has been established that glycated hemoglobin (HbA1C) provides an integrated measure of plasma glucose (PG) of the last 2-3 months. However, the relative contribution of fasting PG (FPG) and postprandial PG (PPG) to the HbA1C value is controversial. OBJECTIVE: To evaluate FPG and PPG contributions to the HbA1C value in patients with type 2 diabetes mellitus (DM2). METHODS: 53 subjects with stable DM2 were studied. They were treated with oral anti-diabetic agents (n = 27) and/or insulin (n = 26). Each subject went to 3 visits at 2-month-intervals. On each visit, FPG, PPG (2 h after breakfast and lunch), and HbA1C were measured and we provided breakfast and lunch according to their meal habits. PG was measured by glucose-oxidase and HbA1C by ion-exchange chromatography. Statistical analysis was performed by correlation coefficients at a < 0.05 P value. RESULTS: Correlations were stronger between HbA1C and post-breakfast PG (r: 0.66-0.48), mean FPG (r: 0.64-0.41), glucose area under the curve (r: 0.64-0.46), and mean PPG (r: 0.59-0.41). CONCLUSIONS: Measurement of post-breakfast PG showed to be another valuable tool for type 2 diabetic glucose control monitoring.

Contribuição da glicemia pós-desjejum para o controle glicêmico do paciente com diabetes melito tipo 2 / Contribution of post-breakfast plasma glucose to the glycemic control of type 2 diabetic patients

Estudos epidemiológicos observaram que glicemias pós-prandiais (GPPs) elevadas são fator principal na ocorrência de doenças cardiovasculares. Sabe-se que a hemoglobina glicada (HbA1C) reflete a glicemia média dos últimos 2-3 meses, entretanto é controversa a contribuição relativa da glicemia de jejum (GJ) e GPP para o valor da HbA1C. OBJETIVO: Avaliar a contribuição da GJ e GPPs para o valor da HbA1C em pacientes com diabetes melito tipo 2 (DM2). MÉTODOS: Participaram 53 indivíduos com DM2, estáveis e em tratamento com antidiabéticos orais (n= 27) e/ou insulina (n= 26). Cada paciente comparecia a 3 visitas a intervalos de 2 meses. Em cada visita era medida a GJ, as GPPs (2h pós-desjejum: GPD e pós-almoço: GPA) e a HbA1C, sendo fornecido o desjejum e o almoço segundo seus hábitos alimentares. Mediu-se a glicose plasmática pela glicose-oxidase e a HbA1C, pela cromatografia de troca iônica. Realizou-se a análise das associações pelo coeficiente de correlação de Spearman, com P< 0,05. RESULTADOS: A HbA1C correlacionou-se melhor em cada visita ao longo do estudo com a GPD (r: 0,66­0,48), a glicemia média (r: 0,64­0,41), a área abaixo da curva glicêmica (r : 0,64­0,46) e a GPP média (r: 0,59­0,41). CONCLUSÕES: A GPD mostrou-se um parâmetro eficaz adicional no monitoramento glicêmico dos pacientes com DM2.

Exercise training increases myocardial inotropic response in food restricted rats.

This study evaluated the effects of exercise training on myocardial function and ultrastructure of rats submitted to different levels of food restriction (FR). Male Wistar-Kyoto rats, 60 days old, were submitted to free access to food, light FR (20%), severe FR (50%) and/or to swimming training (one hour per day with 5% of load, five days per week for 90 days). Myocardial function was evaluated by left ventricular papillary muscle under basal condition (calcium 1.25 mM), and after extracellular calcium elevation to 5.2 mM and isoproterenol (1 microM) addition. The ultrastructure of the myocardium was examined in the papillary muscle. The training effectiveness was verified by improvement of myocardial metabolic enzyme activities. Both 20% and 50% food restriction protocols presented minor body and ventricular weights gain. The 20%-FR, in sedentary or trained rats, did not alter myocardial function or ultrastructure. The 50%-FR, in sedentary rats, caused myocardial dysfunction under basal condition, decreased response to inotropic stimulation, and promoted myocardial ultrastructural damage. The 50%-FR, in exercised rats, increased myocardial dysfunction under basal condition but increased response to inotropic stimulation although there was myocardial ultrastructural damage. In conclusion, the exercise training in severe restriction caused marked myocardial dysfunction at basal condition but increased myocardial response to inotropic stimulation.

Myocardial dysfunction induced by food restriction is related to morphological damage in normotensive middle-aged rats.

Previous works from our laboratory have revealed that food restriction (FR) promotes discrete myocardial dysfunction in young rats. We examined the effects of FR on cardiac function, in vivo and in vitro, and ultrastructural changes in the heart of middle-aged rats. Twelve-month-old Wistar-Kyoto rats were fed a control (C) or restricted diet (daily intake reduced to 50% of the control group) for 90 days. Cardiac performance was studied by echocardiogram and in isolated left ventricular (LV) papillary muscle by isometric contraction in basal condition, after calcium chloride (5.2 mM) and beta-adrenergic stimulation with isoproterenol (10(-6) M). FR did not change left ventricular function, but increased time to peak tension, and decreased maximum rate of papillary muscle tension development. Inotropic maneuvers promoted similar effects in both groups. Ultrastructural alterations were seen in most FR rat muscle fibers and included, absence and/or disorganization of myofilaments and Z line, hyper-contracted myofibrils, polymorphic and swollen mitochondria with disorganized cristae, and a great quantity of collagen fibrils. In conclusion, cardiac muscle sensitivity to isoproterenol and elevation of extracellular calcium concentration is preserved in middle-aged FR rats. The intrinsic muscle performance depression might be related to morphological damage.

[Blockade of renin-angiotensin system attenuates cardiac remodeling in rats undergoing aortic stenosis]. / O bloqueio do sistema renina-angiotensina atenua a remodelação cardíaca de ratos submetidos a estenose aórtica.

OBJECTIVE: To assess the role of the AT1 receptor blocker and the angiotensin-converting enzyme inhibitor in cardiac remodeling induced by aortic stenosis in rats. METHODS: Wistar rats were divided into the following 4 groups: 1) C--control (n=13); 2) AoS--aortic stenosis (n=11); 3) LIS--AoS treated with lisinopril, 20 mg/kg/day (n=11); and 4) LOS--AoS treated with losartan, 40 mg/kg/day (n=9). The treatments were initiated 3 days before surgery. After 6 weeks, the animals underwent echocardiographic study, and quantification of the hydroxyproline (HOP) concentration and the left ventricular (LV) myocyte cross-sectional area (CSA). RESULTS: Aortic stenosis induced an increase in left ventricular wall thickness. The LIS and LOS groups showed no difference as compared with the control group. The AoS and LIS rats had greater left atrial diameters than the control rats did, while no difference was observed in the LOS animals. The AoS animals had greater values of shortening percentage than control animals did. This fact was modified with neither LIS nor LOS. The cross-sectional area of the animals in the AoS group was greater than that in the control group. However, treatment with LOS and LIS attenuated the AoS-induced increase in area. Aortic stenosis caused an increase in HOP concentration, while the LOS group showed no difference as compared with the control group. CONCLUSION: Blockade of the renin-angiotensin system with AT1 blocker and ACEI may attenuate the development of heart hypertrophy, but only the blockade of AT1 receptors attenuates left ventricular interstitial fibrosis.

O bloqueio do sistema renina-angiotensina atenua a remodelação cardíaca de ratos submetidos a estenose aórtica / Blockade of renin-angiotensin system attenuates cardiac remodeling in rats undergoing aortic stenosis

OBJETIVO: Avaliar o papel do bloqueador dos receptores AT1 e do inibidor da enzima conversora da angiotensina na remodelação cardíaca induzida por estenose aórtica em ratos. MÉTODOS: Ratos Wistar foram divididos em 4 grupos: controle (C, n=13), estenose aórtica (EAo, n=11), EAo com lisinopril, 20 mg/kg/dia (LIS, n=11) e EAo com losartan, 40 mg/kg/dia (LOS, n=9). Os tratamentos foram iniciados 3 dias antes da cirurgia. Após 6 semanas, os animais foram submetidos ao estudo ecocardiográfico, quantificação da concentração de hidroxiprolina e da área seccional (CSA) miocitária do ventrículo esquerdo (VE). RESULTADOS: A EAo induziu aumento da espessura da parede do VE. Os animais LIS e LOS não apresentaram diferença em relação aos animais controles. Os ratos EAo e LIS apresentaram maiores diâmetros do átrio esquerdo que os ratos controles, enquanto nos animais LOS não houve diferença. Os animais com EAo apresentaram maiores valores da porcentagem de encurtamento que os controle. Esse fato não foi modificado com LIS ou LOS. A CSA dos animais do grupo EAo foi maior que a dos controle. Entretanto, o tratamento com LOS e com LIS atenuou o aumento da área induzida pela EAo. A EAo resultou em aumento na concentração de HOP, enquanto o grupo LOS não apresentou diferença em relação ao grupo controle. CONCLUSÃO: O bloqueio do sistema renina-angiotensina, com bloqueador AT1 e com IECA, pode atenuar o desenvolvimento de hipertrofia cardíaca, porém só o bloqueio dos receptores AT1 atenua a fibrose intersticial do VE.