Acute effects of temperature and hypercarbia on cutaneous and branchial gas exchange in the South American lungfish, Lepidosiren paradoxa.

The South American lungfish, Lepidosiren paradoxa inhabits seasonal environments in the Central Amazon and Paraná-Paraguay basins that undergo significant oscillations in temperature throughout the year. They rely on different gas exchange organs, such as gills and skin for aquatic gas exchange while their truly bilateral lungs are responsible for aerial gas exchange; however, there are no data available on the individual contributions of the skin and the gills to total aquatic gas exchange in L. paradoxa. Thus, in the present study we quantify the relative contributions of skin and gills on total aquatic gas exchange during warm (35°C) and cold exposure (20°C) in addition to the effects of aerial and aquatic hypercarbia on aquatic gas exchange and gill ventilation rate (fG; 25°C), respectively. Elevated temperature (35°C) caused a significant increase in the contribution of cutaneous (from 0.61±0.13 to 1.34±0.26ml. STPD.h-1kg-1) and branchial (from 0.54±0.17 to 1.73±0.53ml. STPD.h-1kg-1) gas exchange for V̇CO2 relative to the lower temperature (20°C), while V̇O2 remained relatively unchanged. L. paradoxa exhibited a greater branchial contribution in relation to total aquatic gas exchange at lower temperatures (20 and 25°C) for oxygen uptake. Aerial hypercarbia decreased branchial V̇O2 whereas branchial V̇CO2 was significantly increased. Progressive increases in aquatic hypercarbia did not affect fG. This response is in contrast to increases in pulmonary ventilation that may offset any increase in arterial partial pressure of CO2 owing to CO2 loading through the animals' branchial surface. Thus, despite their reduced contribution to total gas exchange, cutaneous and branchial gas exchange in L. paradoxa can be significantly affected by temperature and aerial hypercarbia.

Seroprevalencia y detección de infección primaria por citomegalovirus mediante prueba de avidez IgG en el primer trimestre de embarazo / Seroprevalence and detection of primary infection by cytomegalovirus with IgG avidity test during the first quarter of pregnancy

Objetivo. Conocer la seroprevalencia y detección de infección primaria por citomegalovirus (CMV) mediante prueba de avidez de inmunoglobulina G (IgG) durante el primer trimestre del embarazo en el Hospital General de Morelia, Michoacán. Material y métodos. Se estudiaron 177 pacientes mediante prueba de Elisa modificada, la cual utiliza inmunoanálisis quimioluminiscente de micropartículas (CMIA) para detección de anti-CMV (IgG e inmunoglobulina M [IgM]) e IgG avidez. Resultados. Del total de pruebas, 90.4% resultaron positivas para IgG; de éstas, 2.3% resultaron reactivas a IgM. En este segundo grupo, la prueba de IgG avidez reportó avidez baja en 1.1% y alta en el mismo porcentaje; 9.6% fueron seronegativas. Conclusiones. Se encontró similitud con lo publicado en México. Los profesionales de la salud deben conocer los algoritmos para el diagnóstico y manejo oportuno de la infección por CMV mediante la prueba de avidez de IgG.

Objective. To determine the seroprevalence and detection of primary infection by cytomegalovirus (CMV) with immunoglobulin G (IgG) avidity test during the first quarter of pregnancy in the General Hospital in Morelia, Michoacan. Materials and methods. A total of 177 patients were studied employing a modified Elisa test using a chemiluminescent microparticle immunoassay (CMIA) for the detection of CMV antibodies (IgG and immunoglobulin M [IgM]), and IgG avidity. Results. 90.4% were positive for IgG, and of these, 2.3% were also reactive for IgM, and in this group the IgG avidity test reported low avidity for 1.1% and higher avidity in the same percentage. 9.6% were seronegative. Conclusions. Similarity was found with published studies in Mexico. Health professionals should know the clinical algorithms for diagnosis and proper management of CMV infection using the IgG avidity test.

[Seroprevalence and detection of primary infection by cytomegalovirus with IgG avidity test during the first quarter of pregnancy]. / Seroprevalencia y detección de infección primaria por citomegalovirus mediante prueba de avidez IgG en el primer trimestre de embarazo.

OBJECTIVE: To determine the seroprevalence and detection of primary infection by cytomegalovirus (CMV) with immunoglobulin G (IgG) avidity test during the first quarter of pregnancy in the General Hospital in Morelia, Michoacan. MATERIALS AND METHODS: A total of 177 patients were studied employing a modified Elisa test using a chemiluminescent microparticle immunoassay (CMIA) for the detection of CMV antibodies (IgG and immunoglobulin M [IgM]), and IgG avidity. RESULTS: 90.4% were positive for IgG, and of these, 2.3% were also reactive for IgM, and in this group the IgG avidity test reported low avidity for 1.1% and higher avidity in the same percentage. 9.6% were seronegative. CONCLUSIONS: Similarity was found with published studies in Mexico. Health professionals should know the clinical algorithms for diagnosis and proper management of CMV infection using the IgG avidity test.

Respiratory chemoreceptor function in vertebrates comparative and evolutionary aspects.

The sensing of blood gas tensions and/or pH is an evolutionarily conserved, homeostatic mechanism, observable in almost all species studied from invertebrates to man. In vertebrates, a shift from the peripheral O(2)-oriented sensing in fish, to the central CO(2)/pH sensing in most tetrapods reflects the specific behavioral requirements of these two groups whereby, in teleost fish, a highly O(2)-oriented control of breathing matches the ever-changing and low oxygen levels in water, whilst the transition to air-breathing increased the importance of acid-base regulation and O(2)-related drive, although retained, became relatively less important. The South American lungfish and tetrapods are probably sister groups, a conclusion backed up by many similar features of respiratory control. For example, the relative roles of peripheral and central chemoreceptors are present both in the lungfish and in land vertebrates. In both groups, the central CO(2)/pH receptors dominate the ventilatory response to hypercarbia (60-80%), while the peripheral CO(2)/pH receptors account for 20-30%. Some basic components of respiratory control have changed little during evolution. This review presents studies that reflect the current trends in the field of chemoreceptor function, and several laboratories are involved. An exhaustive review on the previous literature, however, is beyond the intended scope of the article. Rather, we present examples of current trends in respiratory function in vertebrates, ranging from fish to humans, and focus on both O(2) sensing and CO(2) sensing. As well, we consider the impact of chronic levels of hypoxia-a physiological condition in fish and in land vertebrates resident at high elevations or suffering from one of the many cardiorespiratory disease states that predispose an animal to impaired ventilation or cardiac output. This provides a basis for a comparative physiology that is informative about the evolution of respiratory functions in vertebrates and about human disease. Currently, most detail is known for mammals, for which molecular biology and respiratory physiology have combined in the discovery of the mechanisms underlying the responses of respiratory chemoreceptors. Our review includes new data on nonmammalian vertebrates, which stresses that some chemoreceptor sites are of ancient origin.