Polymorphism rs2073618 of the TNFRSF11B (OPG) Gene and Bone Mineral Density in Mexican Women with Rheumatoid Arthritis.

Osteoporosis (OP) is highly prevalent in rheumatoid arthritis (RA) and is influenced by genetic factors. Single-nucleotide polymorphism (SNP) rs2073618 in the TNFRSF11B osteoprotegerin (OPG) gene has been related to postmenopausal OP although, to date, no information has been described concerning whether this polymorphism is implied in abnormalities of bone mineral density (BMD) in RA. We evaluated, in a case-control study performed in Mexican-Mestizo women with RA, whether SNP rs2073618 in the TNFRSF11B gene is associated with a decrease in BMD. RA patients were classified as follows: (1) low BMD and (2) normal BMD. All patients were genotyped for the rs2073618 polymorphism by PCR-RFLP. The frequency of low BMD was 74.4%. Higher age was observed in RA with low BMD versus normal BMD (62 and 54 years, resp.; p < 0.001). Worse functioning and lower BMI were observed in RA with low BMD (p = 0.003 and p = 0.002, resp.). We found similar genotype frequencies in RA with low BMD versus RA with normal BMD (GG genotype 71% versus 64.4%, GC 26% versus 33%, and CC 3% versus 2.2%, resp.; p = 0.6). We concluded that in Mexican-Mestizo female patients with RA, the rs2073618 polymorphism of the TNRFS11B gene is not associated with low BMD.

Association between bone turnover markers, clinical variables, spinal syndesmophytes and bone mineral density in Mexican patients with ankylosing spondylitis.

OBJECTIVES: To compare bone turnover marker (BTM) levels and bone mineral density (BMD) between patients with ankylosing spondylitis (AS) and healthy controls (HC) and to evaluate, in AS, the association between BTM levels and clinical variables, spinal syndesmophytes, and BMD using multivariate analysis. METHOD: Seventy-eight AS patients were compared with 58 HC matched by gender. Spinal syndesmophytes in AS and other characteristics were assessed. C-terminal telopeptide fragments of type I collagen (CTX), bone-specific alkaline phosphatase (BAP), osteocalcin (OC) serum levels, and BMD of the lumbar spine, femoral neck, and forearm were evaluated. RESULTS: AS males and females had lower BAP levels than their respective HC (p < 0.001 and p = 0.001). AS patients with bridging syndesmophytes had higher OC levels than AS patients either with non-bridging syndesmophytes (p = 0.001) or without spinal syndesmophytes (p < 0.001). OC and CTX levels correlated significantly with the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS). In the multivariate linear regression adjusted by age, gender, the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), BMD in the lumbar spine, and C-reactive protein (CRP), we observed an association between BAP levels and anti-tumour necrosis factor (anti-TNF) use (p = 0.05) whereas OC levels were associated with mSASSS (p < 0.001) and anti-TNF use (p = 0.05), and CTX levels were exclusively associated with mSASSS (p = 0.03). In the logistic regression analysis, only OC levels were associated with the presence of syndesmophytes in AS [odds ratio (OR) 2.42, 95% confidence interval (CI) 1.19-5.75]. CONCLUSIONS: We observed an increase in OC levels in AS patients with syndesmophytes. BTM levels were associated with the severity of spinal damage. Future longitudinal studies should evaluate whether these BTMs should be included as tools to determine the prognosis and progression of spinal damage.

Δ6-fatty acid desaturase and fatty acid elongase mRNA expression, phagocytic activity and weight-to-length relationships in channel catfish (Ictalurus punctatus) fed alternative diets with soy oil and a probiotic.

A time-course feeding trial was conducted for 120 days on juvenile channel catfish (Ictalurus punctatus) to study the effects of diets differing in oil source (fish oil or soy oil) and supplementation with a commercial probiotic. Relative levels of Δ6-fatty acid desaturase (Δ6-FAD) and fatty acid elongase (FAE) expression were assessed in brain and liver tissues. Both genes showed similar expression levels in all groups studied. Fish weight-to-length relationships were evaluated using polynomial regression analyses, which identified a burst in weight and length in the channel catfish on day 105 of treatment; this increase was related to an increase in gene expression. Mid-intestinal lactic acid bacterium (LAB) count was determined according to morphological and biochemical criteria using API strips. There was no indication that intestinal LAB count was affected by the modified diets. The Cunningham glass adherence method was applied to evaluate phagocytic cell activity in peripheral blood. Reactive oxygen species (ROS) generation was assessed through the respiratory burst activity of spleen macrophages by the NBT reduction test. Probiotic-supplemented diets provided a good substrate for innate immune system function; the phagocytic index was significantly enhanced in fish fed soy oil and the probiotic, and at the end of the experimental period, ROS production increased in fish fed soy oil. The substitution of fish oil by soy oil is recommended for food formulation and will contribute to promoting sustainable aquaculture. Probiotics are also recommended for channel catfish farming as they may act as immunonutrients.

Photostimulation of Japanese quail.

To adapt commercial poultry production to a new scenario of energy savings and to develop specific practices for quail production aimed at reducing costs while maintaining or improving productivity, four experiments were conducted. In the first experiment, birds were allocated to four treatments (photoperiod duration): T1: 14 L:10 D; T2: 15 L:9 D; T3: 16 L:8 D; and T4: 17 L:7 D. In the second experiment, birds were subjected to four levels of brightness: T1: 5 lux; T2: 10 lux; T3:15 lux; and T4: 22 lux (control). In the third experiment, four types of lamps were evaluated: T1: compact fluorescent lamp (color temperature: 6,500 K); T2: compact fluorescent lamp (color temperature: 2,700 K); T3: incandescent lamp; and T4: yellow LED. In the last experiment, four lighting programs were compared: T1: continuous program (control), in which there was a single photoperiod of 15 h; the other treatments consisted of intermittent lighting programs, as follows: T2: 1 h of light provided 1 h after dusk; T3: 1 h of light provided 2 h before dawn; T4: half an hour of light provided 1 h after dusk and half an hour of light provided 1.5 h before dawn. In each experiment, 1,296 Japanese quail were evaluated for four 28-d cycles, totaling 112 experimental days. A completely randomized experimental design of 4 treatments with 12 replicates of 27 birds each was applied in all trials. Performance and egg quality were evaluated in each experiment. Higher egg production and adequate egg quality, as well as energy savings, can be obtained with Japanese quail using compact fluorescent lamps or LEDs and a photoperiod of 15 h/d supplied using an intermittent lighting program, with 1 h of artificial light 2 h before dawn at a brightness of 5 lux.

Turnover do carbono em sangue e plasma, nas fases crescimento e postura, de codornas japonesas (Coturnix coturnix japonica) / Turnover of carbon in blood and plasma, growth stages and posture, japanese quails (Coturnix coturnix japonica)

O estudo objetivou avaliar o turnover do 13C no sangue e plasma de codornas japonesas utilizando a técnica de isótopos estáveis, para a obtenção do patamar de equilíbrio isotópico que servirá de fundamento para estudos de rastreabilidade. Foram utilizadas 300 aves durante o período experimental de 1-42 e 49-97 dias de idade. Os tratamentos da primeira fase foram constituídos de dietas à base de arroz (C3), contendo ou não farinha de carne e ossos bovinos e um com dieta à base de milho (C4). Nessa primeira fase foi analisado o turnover do sinal isotópico do matrizeiro à base de dietas C4 para dietas à base de C3, como também as diferenças isotópicas das dietas contendo ou não farinha de origem animal. Na segunda fase houve uma substituição de dietas, ou seja, as aves no tratamento C4 da primeira fase passaram a consumir dieta C3, e o tratamento que antes consumia dieta C3 passou para dieta C4. Para determinar a taxa de turnover e o percentual estimado de participação da farinha na composição do material coletado, foi empregado o modelo de diluição isotópica utilizando valores do δ13C. A comparação entre as meias-vidas do sangue e plasma da primeira fase revelou o enriquecimento do δ13C na dieta; já na segunda fase foi possível observar as velocidades de incorporação após a troca das dietas...

The study aimed to evaluate the turnover of 13C in the blood and plasma of Japanese quail using the technique of stable isotopes to obtain the level of isotopic equilibrium that will be the foundation for studies of traceability. A total of 300 birds during the experimental period of 1-42 and 49-97 days of age. The first phase of the treatments consisted of diets based on rice (C3), with or without meat and beef bones and a diet based on corn (C4). This was first examined the turnover signal farm matrix isotope-based diets based diets C4 to C3, as well as isotopic differences of diets with or without animal meal In the second stage there was a substitution of diets, or C4 treatment of the first stage passes to consume C3-based diet than before treatment and diet consumed C3 to C4 diet. To determine the turnover rate and the estimated percentage of participation of flour in the composition of the collected material was used isotope dilution model using δ13C values. A comparison of the half-lives of blood and plasma from the first phase discloses the enrichment of dietary δ 13C, in the second phase was observed after incorporation speeds exchange diets...

Use of organic acids and competitive exclusion product as an alternative to antibiotic as a growth promoter in the raising of commercial turkeys.

A study was conducted to investigate the effects of organic acids (OA) and competitive exclusion product (CE) on growth performance, intestinal morphology, and concentration of volatile fatty acids in the cecal content. The experiment lasted for 10 wk. Four hundred twenty 1-d-old female commercial cross turkey poults (British United Turkeys, BUT Big 9) were distributed into 4 treatments with 5 replicates/pen of 21 birds each. The birds were fed a basal diet without growth promoter (control), diet with lincomycin (44 mg/kg), diet with organic acids (2 g/kg), and diet with product of CE (10(9) cfu/kg). Dietary levels of other nutrients, housing, and general management practices were similar for all treatments. On the first week (d 0-7), the BW and BW gain of the birds that fed diets with OA were lower than in the control group. In the fattening phase (d 28-70), the feed intake of the OA-treated group was lower than compared with the control. The birds that received diet with OA and CE product presented higher concentrations of propionic acid, at 14 d, and butyric acid in cecal content at 28, 56, and 70 d, compared with the control. Dietary inclusion of additives had no significant effects on intestinal villus height, crypt depth, and villus:crypt ratio. Organic acids had negative effects either on early gain or feed intake throughout the study. Because the test was conducted under controlled experimental conditions, the additives that showed results similar to those found by using antibiotics should be studied further in commercial farms to obtain results that can be incorporated into practice.

Electrocardiographic profile of guinea pig heart submitted to Ginkgo biloba extract and its terpenoids / Perfil eletrocardiográfico do coração de cobaia submetido ao extrato de Ginkgo biloba e seus terpenóides

Electrocardiographic effects produced by Ginkgo biloba extract (EGb) and by ginkgolides A (GA) and B (GB), and bilobalide (BB) were investigated in guinea pig heart mounted in Langendorff apparatus (Tyrode, 34 ± 0.1 ºC, 95% O2, 5% CO2). Electrocardiographic parameters were evaluated in the conditions: 1) control with Tyrode and DMSO, 2) EGb (n=4), GA (n=5), GB (n=5) or BB (n=6), and 3) washout. The results showed that 0.1 and 1.0 mg/ml of EGb do not change the electrocardiographic parameters. However, 10 mg/ml of EGb increased the PR interval (PRi) at 21% (p<0.001). This increase was also observed for 50 mM GA (20%, p<0.001) and 70 mM BB (13%, p<0.001), which indicates Ca2+ channel block. However, the 50 mM GB reduced the PRi at 11 % (p<0.001). The GA (23%, p<0.001), GB (16%, p<0.001), and BB (40%, p<0.001) reduced the QT interval (QTi), which suggests the activation of the potassium channel. However, EGb increased QTi (6%, p<0.001). The EGb (28%, p<0.05) and GB (13%, p<0.05) reduced the heart rate. Atrioventricular (AV) block was observed with EGb, GA, and BB. We can conclude that EGb and its terpenoids alter the ECG parameters inducing AV block, which indicates possible arrhythmogenic potential.

Os efeitos eletrocardiográficos produzidos pelo extrato de Ginkgo biloba (EGb) e gingkolídeos A (GA) e B (GB), e bilobalide (BB) foram investigados em coração de cobaia montado sistema de Langendorff (Tyrode, 34 ± 0.1 ºC, 95% O2, 5% CO2). Os parâmetros do ECG foram avaliados nas condições: 1) Tyrode e DMSO, 2) EGb (n=4), GA (n=5), GB (n=5) ou BB (n=6) diluídos em DMSO e 3) washout. Os resultados demonstram que 0,1 e 1,0 mg/mL de EGb não alteraram os parâmetros eletrocardiográficos. Entretanto, 10 mg/ml de EGb aumentaram o intervalo PR (PRi) em 21% (p<0.001). Esse aumento também foi observado com GA a 50µM (20%, p<0,001) e BB a 70 mM (13%, p<0,001) indicando bloqueio de canais de cálcio. Por outro lado, GB reduziu o PRi (11%, p<0,001). O intervalo QT (QTi) foi reduzido por GA (23%, p<0,001), GB (16%, p<0,001) e BB (40%, p < 0.001) sugerindo uma ativação de canais de potássio. Entretanto, EGb aumentou o QTi (6%, p<0.001). A frequência cardíaca foi reduzida por EGb (28%, p<0.05) e GB (13%, p<0.05). Bloqueios átrio-ventriculares (BAV) foram observados com EGb, GA e BB. Podemos concluir que EGb e os terpenos alteram parâmetros eletrocardiográficos induzindo BAV e demonstrando possível potencial arritmogênico.

The -174G/C and -572G/C interleukin 6 promoter gene polymorphisms in mexican patients with rheumatoid arthritis: a case-control study.

OBJECTIVE: There is a lack of information about the genotype frequencies of IL-6 -174G/C and -572G/C polymorphisms in Mexicans with rheumatoid arthritis (RA). Therefore, the aim of this study was to evaluate the association of the IL-6 -174G/C and -572G/C polymorphisms in Mexican mestizo with RA. METHODS: We included 137 patients with RA and 102 healthy controls. Patients were assessed for clinical characteristics. IL-6 -174G/C and -572G/C polymorphisms were genotyped using PCR-RFLP analysis. Allele and genotype frequencies and the Hardy-Weinberg equilibrium were computed. Odds ratios (ORs) were computed to identify the risk for RA associated with the presence of GG genotype in comparison with the GC or CC genotypes. RESULTS: The genotype -174GG occurred at a higher frequency in cases and controls (77.4% versus 78.4%, P = 0.845). We found similar results for the genotype -572GG (54% in patients versus 60.8% in controls, P = 0.295). CONCLUSIONS: This is the first study to evaluate the association of -174G/C and -572G/C polymorphisms of the IL-6 gene with RA in Mexican mestizo patients. These two polymorphisms were not associated with RA in the studied sample. Additional studies are required to evaluate if these IL-6 polymorphisms have relevance to the development of more severe disease.

Gender differences and regionalization of the cultural significance of wild mushrooms around La Malinche volcano, Tlaxcala, Mexico.

The purpose of this study was to determine the cultural significance of wild mushrooms in 10 communities on the slopes of La Malinche volcano, Tlaxcala. The frequency and order of mention of each mushroom species in interviews of 200 individuals were used as indicators of the relative cultural significance of each species. A X(2) analysis was used to compare the frequency of mention of each species between males and females, and a Mann-Whitney U test was used to compare the difference in the total number of fungi mentioned by either gender. Traditional names for mushroom species were documented and frequency of mention assessed through multivariate statistics. The fungi with highest frequency of mention were Amanita basii, Lyophyllum decastes, Boletus pinophilus, Gomphus floccosus and Cantharellus cibarius complex. We found significant differences in the frequency of mention of different fungi by males and females but no significant difference was found for the total number of fungi mentioned by either gender. Principal component analysis suggested a cultural regionalization of La Malinche volcano communities based on preferences for consumption and use of traditional names. We observed two groups: one formed by communities on the eastern part of the volcano (with mixed cultures) and the other including communities on the western slope (ethnic Nahua towns). San Isidro Buensuceso is the most distinct community, according to the criteria in this study.

The mouse pubic symphysis as a remodeling system: morphometrical analysis of proliferation and cell death during pregnancy, partus and postpartum.

Marked changes in mice pubic symphysis occur by the end of pregnancy. Tissue remodeling involves a dynamic balance between cell proliferation and programmed cell death as well as changes in the extracellular matrix components. Therefore, it is important to consider both of these cellular behaviors when investigating the mechanism that regulates interpubic tissue remodeling, growth during late pregnancy and partus ensuring involution during the postpartum period. Proliferating and programmed death cells were identified by immunohistochemistry (proliferating cell nuclear antigen and TUNEL detection, respectively) and the rates at which these processes occurred were determined by morphometric analysis. The results demonstrated that cellular proliferation was intense during the period of ligament formation, from D15 to D18, thereafter abruptly declining on D19. From parturition (D19) onwards, an ever-increasing decline in the cellular proliferation levels could be observed. The quantitative analyses of cellular death showed opposite results when compared to cellular proliferation. During early pregnancy the cycle of cellular renovation was clearly proliferative and during late mouse pregnancy the cycle was directed by programmed cellular death. Although the high levels of cellular death during postpartum involution could be shown by the TUNEL-positive cells, we were unable to observed picnotic nucleus at the light microscopy.

Genotype Ser413/Ser of PAI-2 polymorphism Ser413/Cys is associated with anti-phospholipid syndrome and systemic lupus erythematosus in a familial case: comparison with healthy controls.

BACKGROUND: We describe a family with a 7-year-old proband case diagnosed with systemic lupus erythematosus (SLE) plus secondary anti-phospholipid syndrome (APS) as well as two affected paternal aunts. We compared the frequency of these polymorphisms with healthy controls. OBJECTIVES: To evaluate the mode of inheritance in this familial case of APS and SLE and the possible association of plasminogen activator inhibitor-1 (PAI-1) -675 4G/5G and PAI-2 Ser(413)/Cys polymorphisms. To compare the genotype frequency of these polymorphisms with the results found in a Mexican Mestizo population. METHODS: PAI-1 -675 4G/5G and PAI-2 Ser(413)/Cys were determined by the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) technique using Bsl I and Mwo I on four generations of the family studied. PAI-2 Ser(413)/Cys polymorphism was also determined in 50 healthy individuals of Mexican Mestizo origin. RESULTS: The family pedigree demonstrated that this family did not follow a Mendelian inheritance pattern. When the PAI-2 Ser(413)/Cys polymorphism was examined, we found that 60% (3/5) of the relatives homozygous to Ser(413)/Ser were affected with SLE and/or APS (p = 0.027). The proband case was 4G/5G genotype for the PAI-1 -675 4G/5G polymorphism. No differences between healthy controls of the Mexican Mestizo population and the family studied for the PAI-2 Ser(413)/Cys polymorphism or PAI-1 -675 4G/5G polymorphisms were found. CONCLUSIONS: Our data indicate that this family did not follow the Mendelian inheritance pattern. The Ser(413)/Ser genotype demonstrated in 60% of the affected members (3/5) of this family might increase the risk for autoimmune syndromes such as APS or SLE.

Electrophysiological effects of the aqueous extract of Averrhoa carambola L. leaves on the guinea pig heart.

This work aims to describe some electrophysiological changes promoted by the aqueous extract (AEx) from Averrhoa carambola leaves in guinea pig heart. The experiments were carried out on isolated heart or on right atrium-ventricle preparations. In 6 hearts, the extract induced many kinds of atrioventricular blocks (1st, 2nd, and 3rd degrees); increased the QT interval from 229+/-23 to 264+/-19 ms; increased the QRS complex duration from 27+/-3.1 to 59+/-11 ms, and depressed the cardiac rate from 136+/-17 to 89+/-14b pm. Furthermore, it decreased the conduction velocity of atrial impulse (17+/-3%); reduced the intraventricular pressure (86+/-6%), and increased the conduction time between the right atrium and the His bundle (27+/-6.5%). The conduction time from the His bundle to the right ventricle was not altered. Atropine sulfate did not change either the electrocardiographic parameters or the intraventricular pressure effects promoted by the A. carambola AEx. Based on these results, the popular use of such extracts should be avoided because it can promote electrical and mechanical changes in the normal heart.

Guava extract (Psidium guajava) alters the labelling of blood constituents with technetium-99m.

Psidium guajava (guava) leaf is a phytotherapic used in folk medicine to treat gastrointestinal and respiratory disturbances and is used as anti-inflammatory medicine. In nuclear medicine, blood constituents (BC) are labelled with technetium-99m ((99m)Tc) and used to image procedures. However, data have demonstrated that synthetic or natural drugs could modify the labelling of BC with (99m)Tc. The aim of this work was to evaluate the effects of aqueous extract of guava leaves on the labelling of BC with (99m)Tc. Blood samples of Wistar rats were incubated with different concentrations of guava extract and labelled with (99m)Tc after the percentage of incorporated radioactivity (%ATI) in BC was determined. The results suggest that aqueous guava extract could present antioxidant action and/or alters the membrane structures involved in ion transport into cells, thus decreasing the radiolabelling of BC with (99m)Tc. The data showed significant (P<0.05) alteration of ATI in BC from blood incubated with guava extract.

Molecular mechanisms in normal pregnancy and rheumatic diseases.

Pregnancy is a phenomenon that is not totally understood, based on the complex molecular interactions between the mother and the embrio. Once the fecundation is completed the fetus starts to fight for survival. The first challenge is the implantation process and the second one is the interaction with the maternal immune system. This review discusses how the fetus avoids the immune system rejection, and the mechanisms that the maternal immune system adapts in order to be fit for a successful pregnancy. Also, we focus in this paper on the effects of pregnancy in rheumatic diseases, because the myriad clinical outcomes of the disease itself and the obstetric complications dependent of the disease implicated, as for example in rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), spondyloarthropaties and antiphospholipid syndrome (APS).

Negative inotropic and chronotropic effects on the guinea pig atrium of extracts obtained from Averrhoa carambola L. leaves.

It has been reported that star fruit can lead to a fatal outcome in uremic patients. The intoxication syndrome consists of hiccups, mental confusion, dizziness, and vomiting. On the other hand, folk medicine uses teas and infusions of carambola leaves to treat headache, vomiting, cough, insomnia, and diabetes. This motivated us to determine if Averrhoa carambola can act on the contractility and automaticity of the guinea pig heart. We measured the atrial isometric force in stimulated left atria and determined the chronotropic changes in spontaneously beating right atria. The carambola leaf extracts (1.5 mg/ml) abolished the contractile force in a concentration-dependent manner. Among the crude, methanolic, ethanolic, aqueous, and acetic extracts, the aqueous one was the most potent (EC50 = 520 +/- 94 microg/ml; flavonoids and tannins are the main constituents; Na+ and K+ contents in 1.0 mg/ml of aqueous extract were 0.12 +/- 0.016 and 1.19 +/- 0.15 mM, respectively). The aqueous extract abolished the positive Bowditch staircase phenomenon and reduced the inotropic response to CaCl2 (0.17-8.22 mM), events that are dependent on the cellular Ca2+ inward current. The adrenergic, muscarinic or opioid membrane receptors do not seem to participate in the mechanism of action of the cardioactive substance(s). In spontaneously beating atria, the aqueous extract promoted a negative chronotropic effect that was antagonized by 0.1 microM isoproterenol bitartrate. With this agonist, the EC50 of the aqueous extract increased from 133 +/- 58 to 650 +/- 100 microg/ml. These data regarding the effect of A. carambola on guinea pig atrial contractility and automaticity indicate an L-type Ca2+ channel blockade.

Negative inotropic and chronotropic effects on the guinea pig atrium of extracts obtained from Averrhoa carambola L. leaves

It has been reported that star fruit can lead to a fatal outcome in uremic patients. The intoxication syndrome consists of hiccups, mental confusion, dizziness, and vomiting. On the other hand, folk medicine uses teas and infusions of carambola leaves to treat headache, vomiting, cough, insomnia, and diabetes. This motivated us to determine if Averrhoa carambola can act on the contractility and automaticity of the guinea pig heart. We measured the atrial isometric force in stimulated left atria and determined the chronotropic changes in spontaneously beating right atria. The carambola leaf extracts (1.5 mg/ml) abolished the contractile force in a concentration-dependent manner. Among the crude, methanolic, ethanolic, aqueous, and acetic extracts, the aqueous one was the most potent (EC50 = 520 ± 94 æg/ml; flavonoids and tannins are the main constituents; Na+ and K+ contents in 1.0 mg/ml of aqueous extract were 0.12 ± 0.016 and 1.19 ± 0.15 mM, respectively). The aqueous extract abolished the positive Bowditch staircase phenomenon and reduced the inotropic response to CaCl2 (0.17-8.22 mM), events that are dependent on the cellular Ca2+ inward current. The adrenergic, muscarinic or opioid membrane receptors do not seem to participate in the mechanism of action of the cardioactive substance(s). In spontaneously beating atria, the aqueous extract promoted a negative chronotropic effect that was antagonized by 0.1 æM isoproterenol bitartrate. With this agonist, the EC50 of the aqueous extract increased from 133 ± 58 to 650 ± 100 æg/ml. These data regarding the effect of A. carambola on guinea pig atrial contractility and automaticity indicate an L-type Ca2+ channel blockade.

Efeito da idade da matriz sobre o desempenho e rendimento de carcaça de frangos de corte / Effect of broiler breeder age on performance and carcass yield of broiler chickens

Avaliou-se efeito da idade da matriz sobre as características de desempenho, rendimento de carcaça e partes de frangos de corte, criados até 49 dias de idade. Foram utilizados 3600 pintos de um dia, oriundos de ovos de matrizes da linhagem Ross 308, distribuídos segundo um delineamento experimental inteiramente ao acaso, em esquema fatorial 5I2, com cinco idades de matrizes (29, 41, 58, 68 e 98 semanas) e dois sexos, com quatro repetições de 90 aves cada. Aos 21, 28, 35, 42 e 49 dias de idade, cinco frangos por parcela foram amostrados e abatidos após jejum alimentar de oito horas, para avaliação do rendimento de carcaça e partes. A idade da matriz influenciou (P<0,05) o desempenho das aves na fase inicial de criação (1 a 21 dias); os frangos oriundos de matrizes com 29 semanas de idade apresentaram menor rendimento. A idade da matriz não afetou (P>0,05) o rendimento de carcaça nas idades avaliadas. Os frangos oriundos de matrizes com 29 semanas apresentaram melhor rendimento de peito que aqueles de matrizes com 58 semanas. O sexo influenciou (P<0,05) tanto o desempenho quanto o rendimento de carcaça e partes dos frangos de corte.

Inotropic effect of Citrus sinensis (L.) Osbeck leaf extracts on the guinea pig atrium.

The objective of the present investigation was to determine the contractile effect of crude and acetone leaf extracts of Citrus sinensis (L.) Osb. on mammalian myocardium. Crude leaf extracts have been used in folk medicine to treat neurological disorders. Some flavonoids isolated from this plant presented a positive inotropic effect on myocardium. This motivated us to test the extracts on the atria of guinea pigs of both sexes (300-500 g) and surprisingly we observed inotropic depression instead of an increase in force. The maximum effect of the crude extract was 79.4 +/- 8.1% of the control force amplitude (N = 5 hearts, 10 trials, 27 +/- 0.1 degrees C, stimulus: 2 Hz, 400 V, 0.5 ms). The EC50 for crude, ethanol, acetic, aqueous, and acetone extracts was 300, 300, 600, 1000, and 140 microg/ml, respectively, with a Hill constant of 1.8, 2.0, 2.5, 2.0, and 1.4, respectively. Blockade of cholinergic, beta-adrenergic, or opioid membrane receptors with 1.5 microM atropine sulfate, 1 microM propranolol, and 10 microM naloxone, respectively, did not change the effect of the crude extract. The acetone extract abolished the Bowditch positive staircase phenomenon (N = 5 hearts, 10 trials, 27 +/- 0.1 degrees C), suggesting a possible reduction of the calcium inward current, and also promoted the so-called Woodworth phenomenon. The effect was concentration-dependent and indicated the existence of another inhibitory contractile mechanism such as the simultaneous activation of some of the membrane potassium channels reducing the myocardial action potential duration and further decreasing the cellular calcium entry.

Inotropic effect of Citrus sinensis ( L. ) Osbeck leaf extracts on the guinea pig atrium

The objective of the present investigation was to determine the contractile effect of crude and acetone leaf extracts of Citrus sinensis (L.) Osb. on mammalian myocardium. Crude leaf extracts have been used in folk medicine to treat neurological disorders. Some flavonoids isolated from this plant presented a positive inotropic effect on myocardium. This motivated us to test the extracts on the atria of guinea pigs of both sexes (300-500 g) and surprisingly we observed inotropic depression instead of an increase in force. The maximum effect of the crude extract was 79.4 ± 8.1 percent of the control force amplitude (N = 5 hearts, 10 trials, 27 ± 0.1°C, stimulus: 2 Hz, 400 V, 0.5 ms). The EC50 for crude, ethanol, acetic, aqueous, and acetone extracts was 300, 300, 600, 1000, and 140 æg/ml, respectively, with a Hill constant of 1.8, 2.0, 2.5, 2.0, and 1.4, respectively. Blockade of cholinergic, beta-adrenergic, or opioid membrane receptors with 1.5 æM atropine sulfate, 1 æM propranolol, and 10 æM naloxone, respectively, did not change the effect of the crude extract. The acetone extract abolished the Bowditch positive staircase phenomenon (N = 5 hearts, 10 trials, 27 ± 0.1°C), suggesting a possible reduction of the calcium inward current, and also promoted the so-called Woodworth phenomenon. The effect was concentration-dependent and indicated the existence of another inhibitory contractile mechanism such as the simultaneous activation of some of the membrane potassium channels reducing the myocardial action potential duration and further decreasing the cellular calcium entry.