Acta cientifica venezolana最新文献_第6页

[Abundance of sea urchin Lytechinus variegatus (Lamarck) on North, East and West coasts of Margarita Island (Venezuela) ]. [玛格丽塔岛(委内瑞拉)北、东、西海岸海胆Lytechinus variegatus (Lamarck)的数量]。

Acta cientifica venezolana Pub Date : 2002-01-01

Alfredo Gómez Gaspar

{"title":"[Abundance of sea urchin Lytechinus variegatus (Lamarck) on North, East and West coasts of Margarita Island (Venezuela) ].","authors":"Alfredo Gómez Gaspar","doi":"","DOIUrl":"","url":null,"abstract":"The sea urchin roe reach a very high price in the international fish product market favoring the increase in the catches of this resource and overfishing in some countries. In the Island of Margarita (Venezuela) some species, Lytechinus variegatus (Lamarck) among others, are consumed as food but studies to determine abundance of the resource are unknown. Nine sample stations (depth less than 2 m) on the North, East and West coast of Margarita Island were visited in six different occasions between February/1998 and February/1999 to study the population density (urchins/m2) of L. variegatus. Using a quadrat (0.25 m2) thrown 8 times over seagrasses (Thalassia testudinum) beds and over submerged rocks and the urchins removed by dive. The diameter of each specimen was measured and returned to the sea. The water temperature, salinity and dissolved oxygen of each site was measured. Were collected a total of 2,073 urchins with a diameter ranging from 11.0 to 84.5 mm and population density between 1 to 52 urchins/m2. The mean size of specimens collected in the stations was between 30.44 and 55.09 mm and average density fluctuated between 3.2 to 43.2 urchins/m2. The station where sea urchins were found to be most abundant was the North coast (Manzanillo fishing villae) where they live on rocks with a density (38 a 52/m2) far over the values previously cited for the Caribbean sea and Florida.","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 1","pages":"15-20"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21977440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

[Effect of hypoproteic diets enriched with essential and non-essential amino acids on the uninephrectomized rat ]. [富含必需氨基酸和非必需氨基酸的低蛋白饮食对未去肾大鼠的影响]。

Acta cientifica venezolana Pub Date : 2002-01-01

Virginia Leticia Colina, Margarita Pérez-Gonzalez, Jacobo Villalobos, Vito Lamanna

{"title":"[Effect of hypoproteic diets enriched with essential and non-essential amino acids on the uninephrectomized rat ].","authors":"Virginia Leticia Colina, Margarita Pérez-Gonzalez, Jacobo Villalobos, Vito Lamanna","doi":"","DOIUrl":"","url":null,"abstract":"Hyperalimentation solutions, with low protein content but rich in amino acids, have been more frequently used as a dietary treatment for renal terminal patients, with the purpose to increase their survival. However, the literature in this respect is contradictory. Some authors justify the use of amino acids due to the fact that they seem to regenerate damaged tubular cells (glycine, for example). Other authors, on the contrary, do not agree with this position, since some amino acids, like L-Serine and Lysine, are nephrotoxic. In 1977, it was demostrated that Lysine and Arginine inhibited protein tubular reabsorption, inducing proteinuria, while Glycine, Alanine, Asparagine and Glutamic Acid did not. In order to clarify this issue, we carried out a controlled animal study using uninephrectomized rats fed during nine weeks, with different hypoproteinic diets (4% protein content), enriched individually with five different amino acids. The hypoproteinic diets were enriched with Lysine and Arginine (essential amino acids) and Proline, Glutamic Acid and Asparagine (non essential amino acids). Assays for serum biochemical markers and renal function were carried-out pre-nephrectomy, two weeks after nephrectomy (post-nephrectomy control) and nine weeks post-diet for all the animals, no matter the diet to which they were subjected, the serum biochemistry results showed that all the hypoproteinic diets, enriched with amino acids, affected the renal function. The nephrotoxicity of the tested amino acids, followed this decreasing order: Glutamic Acid > Proline > Lysine > Asparagine > Arginine. hypoproteinic diets enriched with Lysine, Asparagine and Arginine, produced glomerular hyperfiltration, without proteinuria. In summary, our results point towards the idea that, contrarily to what has been described in the literature by some authors: enrichment of hypoproteinic diets with certain amino acids does not seem to protect against progression of renal disease in physiologically compromised kidneys.","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 1","pages":"21-8"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21977441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Serum enzyme pattern and local enzyme gradients in chronic chagasic patients. 慢性血吸虫病患者血清酶谱及局部酶梯度。

Acta cientifica venezolana Pub Date : 2002-01-01

Oscar Marino Alarcón-Corredor, Hugo Carrasco-Guerra, María Ramírez de Fernández, Wanda León

{"title":"Serum enzyme pattern and local enzyme gradients in chronic chagasic patients.","authors":"Oscar Marino Alarcón-Corredor, Hugo Carrasco-Guerra, María Ramírez de Fernández, Wanda León","doi":"","DOIUrl":"","url":null,"abstract":"Histochemical studies of myocardial biopsies from chronic chagasic patients at different evolutive stages showed a pattern primarily characterized by a marked increment in tissue enzymes such as mono-amine oxidase and lysosomal acid phosphatase. This cellular damage can be reflected by changes in certain serum enzymes associated with myocardial metabolism, specially in the coronary sinus, where the blood metabolized by the heart is drained. However, little is known about the possible changes in blood enzyme activity during chronic Chagas disease. In this investigation, the activity of the following enzymes glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), alkaline phosphatase (ALP), acid maltase (AM), lactate dehydrogenase (LDH), alpha-hydroxybutyric dehydrogenase (alpha-HBDH or LDH1) and creatine phosphokinase (CPK) was measured in blood serum of the superior cava vein (SCV), coronary sinus (CS) and pulmonary (PA) and femoral (FA) arteries of 45 chronic chagasic patients, ages between 20 and 55 yr, at different evolutive stages (groups IA, IB, II and III). The results demonstrate that the average activity of the enzymes studied in chagasic patients, except LDH and CPK, are significantly altered (p < 0.05) in the majority of the arterial and venous blood samples. The finding of released GOT, GPT, ALP, acid maltase and alpha-HBDH in groups IA and IB is an indication of early myocardial damage in chronic chagasic patients without clinical evidence of cardiac disease. In conclusion, it is suggested that the possible evolutive pattern for myocardial damage could be established by the increment in coronary sinus blood of the enzymes GOT, acid maltase and alpha-HBDH.","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 3","pages":"210-7"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22308148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

[Improvement of somatic embryogenesis process in sugarcane Venezuelan cultivars]. [委内瑞拉甘蔗品种体细胞胚胎发生过程的改进]。

Acta cientifica venezolana Pub Date : 2002-01-01

Ana Karina Marcano, Pedro Molina Guevara, Maira Oropeza, Eva de García

引用次数: 0

[New physiological records for Turiamo Bay, Henri Pittier National Park, Aragua, Venezuela]. [委内瑞拉阿拉瓜亨利皮蒂埃国家公园图里亚莫湾的新生理记录]。

Acta cientifica venezolana Pub Date : 2002-01-01

Beatriz Vera, Ernesto Foldats

引用次数: 0

Laboratory scale production of maltodextrins and glucose syrup from banana starch. 实验室规模用香蕉淀粉生产麦芽糊精和葡萄糖浆。

Acta cientifica venezolana Pub Date : 2002-01-01

Luis Arturo Bello-Pérez, Laura Sánchez-Hernández, Esther Moreno-Damían, Jorge F Toro-Vazquez

{"title":"Laboratory scale production of maltodextrins and glucose syrup from banana starch.","authors":"Luis Arturo Bello-Pérez, Laura Sánchez-Hernández, Esther Moreno-Damían, Jorge F Toro-Vazquez","doi":"","DOIUrl":"","url":null,"abstract":"Banana starch was isolated to obtain maltodextrin by enzymatic hydrolysis with a heat-stable alpha-amylase. The maltodextrin obtained had a dextrose equivalent (DE) between 7-11 and showed suitable chemical characteristics for food application. Additionally, banana maltodextrin had a greater white color value and total color difference (delta E) than a sample of commercial maltodextrin. Further saccharification of the maltodextrins was carried out with amyloglucosidase and pullulanase at 60 degrees C during 24 h obtaining a glucose syrup. Chemical characteristics of banana glucose syrup were compared with those of a commercial syrup obtaining similar results. Nevertheless, the color of banana glucose syrup was clearer than the one of a sample of commercial syrup. However, it showed lower color stability than the commercial sample, i.e., the color of banana glucose syrup changed as a function of storage time. Banana starch may be used to obtain maltodextrins and glucose syrups with similar chemical characteristics of those obtained from maize starch. Particularly, the color of banana maltodextrin is adequate for its use in food products.","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 1","pages":"44-8"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21977448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

[Potential antimitotics. 2. Synthesis of 1-benzyl-3-carbethoxy-2-quinolones]. (潜在的抗有丝分裂的。2. 1-苄基-3-碳氧基-2-喹诺酮类化合物的合成

Acta cientifica venezolana Pub Date : 2002-01-01

María A Lorenzo, Wilmer Guzmán, Carlos J Márquez

引用次数: 0

[Effects of skeletal muscle proteins on corrosion of stainless steels]. [骨骼肌蛋白对不锈钢腐蚀的影响]。

Acta cientifica venezolana Pub Date : 2002-01-01

Christian Rojas, María E Lago

{"title":"[Effects of skeletal muscle proteins on corrosion of stainless steels].","authors":"Christian Rojas, María E Lago","doi":"","DOIUrl":"","url":null,"abstract":"The corrosion behavior of AISI 304 and AISI 316 stainless steels and a steel that matches the requirements of the ASTM Standard F-138 of possible use in traumatology, was studied in the presence of skeletal muscle proteins. The investigation was carried out using potentiodynamics polarization measurements and cyclic polarization, using a fluid of the same protein and salt composition than skeletal muscle. To evaluate the effect of the proteins, the tests were performed with and without the addition of proteins to the cellular fluid at 37 degrees C. The electrochemical assays revealed a negative effect of proteins on pitting corrosion, according to the quality of the steel used to carry out the assays; the most resistant being the AISI 316L and the F-138. In the presence of proteins scanning electron microscopy (SEM) carried out after cyclic polarization revealed a mixed layer, formed by oxides and proteins stuck to the metal surface. This layer seems to be a more unstable passive layer than the corresponding one formed in the absence of proteins. The Tafel plot in the presence of proteins revealed that the corrosion mechanism was controlled by diffusional process. The results with respect to pitting corrosion were similar to those obtained in marine environments.","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 2","pages":"156-63"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22186066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

[Chemical characterization of Brazilian oat genotypes]. [巴西燕麦基因型的化学特性]。

Acta cientifica venezolana Pub Date : 2002-01-01

Rosane Costa Beber, Alicia de Francisco, Antonio Carlos Alves, Roberta Marins de Sá, Paulo Ogliari

引用次数: 0

[Radioactivity for 137Cs, 125I, 131I, 59Fe, y 57Co windows from foods included in the basic alimentary basket and in the water, consumed in the state of Carabobo, Venezuela]. [委内瑞拉卡拉波波州食用的基本食物篮子和水中的137Cs, 125I, 131I, 59Fe, y 57Co窗口的放射性]。

Acta cientifica venezolana Pub Date : 2002-01-01

Annabell Torres, María Tovar, Oscar Malpica, Antonio Eblen-Zajjur

{"title":"[Radioactivity for 137Cs, 125I, 131I, 59Fe, y 57Co windows from foods included in the basic alimentary basket and in the water, consumed in the state of Carabobo, Venezuela].","authors":"Annabell Torres, María Tovar, Oscar Malpica, Antonio Eblen-Zajjur","doi":"","DOIUrl":"","url":null,"abstract":"One of the input ways of radionucleids into the organism is through food intake. The aim of the present study is to measure the radioactivity levels in food and water samples within energy windows corresponding to 137Cs, 125I, 131I, 59Fe, and 57Co. Samples were taken from local and imported food belonging to the venezuelan basic alimentary basket and included: beef meat, hen egg, chicken bone, tomato, black bean, rice, powder milk from local dealers or imported from Italy and New Zeeland, potable water from the Valencia city aqueduct and bottled water from local sources or imported from Portugal. Radioactivity was measured with a well type Nal (TI) scintillation counter. Analyzed foods and water presented levels lower than the minimal detectable activity for 137Cs, 131I, 59Fe, 57Co, but it was detected in the Valencia city aqueduct water and in bottled water imported from Portugal, levels greater than the minimal detectable activity for the 125I energy window. These results strongly suggest the need of repeated multienergy windows monitoring of radioactivity of basic alimentary basket foods and potable water.","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 4","pages":"279-83"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22552333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0