Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SOUTH AMERICA”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources
PubMed2006

Last Glacial mammals in South America: a new scenario from the Tarija Basin (Bolivia).

The chronology, sedimentary history, and paleoecology of the Tarija Basin (Bolivia), one of the richest Pleistocene mammalian sites in South America, are revised here based on a multidisciplinary study, including stratigraphy, sedimentology, geomorphology, paleontology, isotope geochemistry, and (14)C geochronology. Previous studies have indicated a Middle Pleistocene age for this classic locality. We have been able to obtain a series of (14)C dates encompassing all the fossil-bearing sequences previously studied in the Tarija Basin. The dated layers range in age from about 44,000 to 21,000 radiocarbon years before present (BP), indicating that the Tarija fauna is much younger than previously thought. Glacial advances correlated to marine isotopic stages (MIS) 4 and 2 (ca. 62 and 20 ka BP, respectively) are also documented at the base and at the very top of the Tarija-Padcaya succession, respectively, indicating that the Bolivian Altiplano was not dry but sustained an ice cap during the Last Glacial Maximum. The results of this multidisciplinary study enable us to redefine the chronological limits of the Tarija sequence and of its faunal assemblage and to shift this paleontological, paleoclimatological, and paleoecological framework to the time interval from MIS 4 to MIS 2.

Animals↗
PubMed2006

Andes Hantavirus as possible cause of disease in travellers to South America.

BACKGROUND: Hantaviruses in Europe and Asia cause haemorrhagic fever with renal syndrome and epidemic nephritis (mortality rate <1-15%). New strains of Hantaviruses cause Hantavirus pulmonary syndrome (HPS) from Canada to South America. Andes virus mortality rate is about 30% in Chile. METHOD: Clinical charts of 54 patients were reviewed. RESULTS: Inhalation of aerosolized urine, faeces or saliva of rodents is the principal cause of infection. The incubation period is between 8 and 43 days. The main prodromal symptoms are: myalgias, fever, fatigue, gastrointestinal disorders, dyspnoea, petechiae and coughing. After the 4th day pulmonary oedema, hypotension and renal failure appear. Haemorrhagic disorders may occur. The first laboratory tests presenting alterations are: haemoconcentration, leukocytosis, low platelet count <150 micro/L, and presence of immunoblasts. The treatment is supportive: mechanical ventilation, vasopressor drugs, haemofiltration or haemodialysis, and extracorporeal membrane oxygenation. There is no specific treatment for HPS. Preventive measures must be empathised. CONCLUSION: The principal risk factors for tourists are: accommodation in abandoned or closed up facilities; failure to use indicated pathways when walking in forests; camping outside recommended areas; drinking water from natural sources and fishing in risk areas. The risk of infection for foreign tourists in Chile is low.

Animals↗
PubMed1986

The Multiple Forms of alpha-Amylase Enzyme of the Araucaria Species of South America: A. araucana (Mol.) Koch and A. angustifolia (Bert.) O. Kutz : A Comparative Study.

alpha-Amylase is one of the major enzymes present in the seeds of both Araucaria species of South America and it initiates starch hydrolysis during germination and early seedling growth. The pattern of the multiple forms of alpha-amylase of the two Araucaria species was investigated by electrophoresis and isoelectrofocusing of the native enzyme in polyacrylamide gels. The enzyme forms were compared in the embryo and megagametophyte of quiescent seeds and of seeds imbibed for 18, 48, and 90 hours. Specific alpha-amylase enzyme forms appear and disappear during these imbibition periods showing both similarities and differences between tissues and species. Before imbibition, there are five alpha-amylase forms identical in both tissues, but different between species. After 18 hours of imbibition, there are two enzyme forms in both tissues of Araucaria araucana seeds, only one form in the embryo of Araucaria angustifolia but two forms in the megagametophyte of this specie. After 48 hours of seed imbibition, most of the enzyme forms present in quiescent seeds reappear. At 90 hours of imbibition different enzyme forms are detected in the embryo with respect to the gametophyte. The changes in form patterns of alpha-amylase are discussed according to a possible regulation of gene expression by endogenous gibberellins.

Journal Article↗
PubMed2006

Hyperlexia in Spanish-speaking children: report of 2 cases from Colombia, South America.

Hyperlexia is a condition rarely reported in Spanish-speaking children, characterized by the ability to recognize written words without formal training. We present two unrelated autistic children with hyperlexia from Colombia (South America) who were followed for 8 years with formal neuropsychological evaluations of language, motor skills, visual perception, attention and behavior. Both children taught themselves to read before 5 years of age but showed minimal comprehension; both displayed obsessional reading and difficulties in social skills and attention. Brain CT scans were normal. Hyperlexia has been associated with hyperactivation of the left superior temporal cortex; we conclude that the orthographic route is a probable mechanism for the development of hyperlexia.

Adolescent↗
PubMed1999

Mayaro virus disease: an emerging mosquito-borne zoonosis in tropical South America.

This report describes the clinical, laboratory, and epidemiological findings on 27 cases of Mayaro virus (MV) disease, an emerging mosquito-borne viral illness that is endemic in rural areas of tropical South America. MV disease is a nonfatal, dengue-like illness characterized by fever, chills, headache, eye pain, generalized myalgia, arthralgia, diarrhea, vomiting, and rash of 3-5 days' duration. Severe joint pain is a prominent feature of this illness; the arthralgia sometimes persists for months and can be quite incapacitating. Cases of two visitors from the United States, who developed MV disease during visits to eastern Peru, are reported. MV disease and dengue are difficult to differentiate clinically.

Adult↗
PubMed1996

Failure of combined chloroquine and high-dose primaquine therapy for Plasmodium vivax malaria acquired in Guyana, South America.

The presence of chloroquine-resistant Plasmodium vivax malaria in the New World has been suspected but not confirmed. We report the cases of three patients who acquired vivax malaria in Guyana, South America, and for whom standard chloroquine therapy (25 mg/kg) failed despite therapeutic blood levels. The optimal treatment of chloroquine-resistant P. vivax malaria is unknown, but recent studies suggest that a combination of chloroquine (25 mg/kg) and high-dose primaquine (2.5 mg/kg over 48 hours) is effective therapy. Two of our patients had recurrences of P. vivax malaria 6-8 weeks after receiving directly observed therapy with this combination. These cases confirm the presence of chloroquine-resistant P. vivax in Guyana and emphasize the need for better treatment regimens for chloroquine-resistant and primaquine-resistant P. vivax malaria.

Adult↗
PubMedDate not supplied

Specific histologic features of Santa Marta hepatitis: a severe form of hepatitis delta-virus infection in northern South America.

Stimulated by observations in an outbreak of hepatitis delta-virus infection among Yucpa Indians in Venezuela, in which unusual histologic features were found, we studied 100 cases of fatal hepatitis from Colombia, South America, which had been obtained by autopsy or viscerotomy. These cases were considered to be "Santa Marta hepatitis," or "hepatitis of the Sierra Nevada de Santa Marta," which has been observed in this region for more than 40 years. Of the 100 cases, 19 had a variety of histologic lesions or were normal, and hepatitis delta-virus antigen was not demonstrated immunocytochemically in any of them. By contrast, 81 cases had a characteristic histologic picture with intense microvesicular steatosis associated with conspicuous eosinophilic necrosis of the hepatocytes, which apparently were sluggishly removed by cytolysis. Hepatitis delta-virus antigen was detected in 70% of the 81 cases, and the absence of detection of this antigen was often associated with poor tissue preservation and more extensive hepatocyte necrosis. A smaller percentage of patients had hepatitis B virus antigens detectable in liver tissue. The characteristic lesion in these 81 cases could be distinguished from other causes of microvesicular steatosis by the extensive eosinophilic necrosis. Other variable accompanying features included intraacinar, mainly macrophagic, scavenger cell inflammation, intense portal inflammation, a parenchymal regeneration, and ductular and arteriolar proliferation. Santa Marta hepatitis as a severe form of hepatitis delta-virus infection differs markedly from fulminant delta-hepatitis in Europe and the United States in which the microsteatosis with marked eosinophilic degeneration is not found. The causes for these differences are unknown but may relate to nutritional factors or environmental toxins.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Viral↗