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    ABSTRACT: Rainbow trout were introduced to Lake Titicaca in 1942. A commercial trout canning operation started in 1961 but terminated in 1970. Data for this study were collected in 1966 and 1967, with the object of examining the life history, biology, and commercial fishery of Titicaca rainbow trout. Trout were caught commercially and experimentally by gillnets in different parts of the lake.Lake Titicaca lies across the border of Peru and Bolivia at 3212 m above sea level. The physico-chemical characteristics of the lake appear ideal for self-sustaining populations of rainbow trout. Growth was constant throughout the year, and was good in relation to growth rates of rainbow trout in other parts of the world. Spawning took place in the tributaries in the winter. Recruitment to the fishery occurs in 7.62 cm stretch mesh gillnets at about 27 cm fork length.The total annual commercial catch increased to 500 metric tons in 1965 before subsequently decreasing. The simplest explanation for the decline in total catch would be the increase in fishing mortality due to increased fishing effort, although it is possible that the decline in water level has had some effect. It appeared possible that the lake could sustain an annual catch of about 350 tons.
    Journal of Fish Biology 01/2006; 5(4):429 - 440.
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    ABSTRACT: This study analyses the manner in which trophoblast cells adhere to uterine epithelium and the subsequent interactions that contribute to the establishment of epitheliochorial placentation in the alpaca Lama pacos. Specimens at the luteal and follicular phases and at 22, 26, 30 and 45 days of pregnancy (op) were processed for morphological studies. On day 15 op, the blastocysts are completely free within the uterine lumen, with implantation starting around day 20. On days 22 and 26 of gestation, the trophoblast is apposed to the epithelial surface of the uterus, with areas of contact and adhesion by means of complex interdigitation. Implantation sites occur prevalently in the left uterine horn, but an expanded trophoblast also occupies large extensions of the right horn, where the maternofetal interaction shows peculiar areas of apposition. As development continues, attachment areas become more extensive. On days 30 and 45, many secretory granules can be seen in the uterine epithelium, while giant multinucleate cells appear interposed between the remaining trophoblast cells, showing intense alkaline phosphatase activity, deposits containing iron and PAS-positive granules. Placental lactogen hormone is not present within the cytoplasm of the binucleate or multinucleate trophoblast cells. By day 30 of gestation, the trophoblast layer is lined by an extraembryonic connective tissue that by day 45 is well vascularized, thus indicating the starting point of placental formation. Fetal and maternal capillaries indent the epithelium and the trophoblast, narrowing the specialized areas of exchange, which occur along the entire maternofetal interface, characterizing the diffuse nature of this placenta.
    Anatomy and Embryology 01/2004; 207(4-5):317-31.
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    ABSTRACT: Reproduction in South American camelids is poorly studied. To extend our knowledge of the development and cellular physiology of the placenta in the alpaca Lama pacos, we have examined specimens from day 150 of pregnancy to term. Morphological investigations using light, transmission and scanning electron microscopy, the histochemical localization of iron, alkaline and acid phosphatase activity, and the immunodetection of placental lactogen hormone were performed. Throughout pregnancy there was a progressive increase in the depths of folds on the uterine mucosa surface together with a thickening of the endometrium. Glandular cells exhibited PAS and acid phosphatase (AcP) positive secretion granules. In the chorion, giant trophoblast polyploid cells gradually became more numerous and larger. Non-giant cells exhibited positive granules for PAS, alkaline phosphatase (AkP) reaction and immunostaining for bovine placental lactogen hormone (PLH). SDS -PAGE electrophoresis and Western blotting procedures also confirmed the presence of a bovine PLH-like glycoprotein in the fetal alpaca placenta. Over the glandular openings, the chorion formed typical areolae, where the trophoblast exhibited AcP and PAS positive reactions. At these sites, the fetal endothelial cells contained iron-storage granules in their cytoplasm. The trophoblast-epithelial interface exhibited a complex microvillous interdigitation, in which an AkP reaction was very prominent. The chorionic capillaries progressively indented adjacent trophoblast cells. These data suggest that although the epitheliochorial alpaca placenta is diffuse, various trophoblast cell types and specialized areas of the maternofetal interface give the placenta micro-regional functions where histiotrophic nutrition, hormone production and molecular exchange are prevalent.
    Anatomy and Embryology 08/2003; 207(1):45-62.


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    Puno, Peru
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