Loading...
(1/892) Distribution of keratins, vimentin, and actin in the testis of two South American camelids: vicuna (Vicugna vicugna) and llama (Lama glama). An immunohistochemical study.

The purpose of the present study was to investigate the pattern of distribution of cytokeratins, vimentin and muscular actin in the testis of vicuna (Vicugna vicugna) and llama (Lama glama) two species of camelids native of the Andean high plateau of South America. Testicular biopsies of four vicunas and five llamas were used. Animals were healthy breeders. The tissues were processed by standard immunohistochemistry with antipancytokeratinAE1/AE3, antikeratin 18 (K 18), CAM 5.2 (antikeratin 5, 18, and 19), antivimentin, and smooth-muscle-specific antiactin antibodies to track the cytoskeletal pattern of testicular cells. Using AE1/AE3 antibody the immunostaining was found in the epithelial lining of tubuli recti and rete testis. The reaction was relatively stronger in the apical cytoplasm of epithelial cells. The testicular cells of the two species showed no reaction to K 18 and CAM 5.2 antibodies. Antivimentin antibody stained the basal cytoplasm of the Sertoli cells, the Leydig cells, and the epithelial lining of tubuli recti and rete testis. In the last two structures the immunostain was relatively more intense in the basal cytoplasm of epithelial cells. Antiactin antibody stained the peritubular cells and the muscle cells of the lamina propria oftubuli recti and rete testis. The presence in these species of only some keratins found in man, its coexpression with vimentin in epithelial lining of tubuli recti and rete testis and the peritubule organization, so different from other ungulates may reflect a differential adaptation of the cytoskeleton to particular reproductive strategies.  (+info)

(2/892) Health maintenance organizations in developing countries: what can we expect?

Health maintenance organizations (HMOs) are a relatively new and alternative means of providing health care, combining a risk-sharing (insurance) function with health service provision. Their potential for lowering costs has attracted great interest in the USA and elsewhere, and has raised questions regarding their applicability to other settings. Little attention, however, has been given to critically reviewing the experience with HMOs in other countries, particularly concerning their introduction to settings other than the USA. This paper first reviews the current experience of HMOs in low- and middle-income countries, including Argentina, Bolivia, Brazil, Colombia, Ecuador, Uruguay, Chile and Indonesia. Secondly, the paper reviews the USA experience with HMOs: prerequisites for the establishment of HMOs in the USA are identified and discussed, followed by a review of the performance of HMOs in terms of cost containment, integration of care and quality of care for the elderly and poor. The analysis concludes that difficulties may arise when implementing HMOs in developing countries, and that potential adverse effects on the overall health care delivery system may occur. These should be avoided by careful analyses of a nation's health care system.  (+info)

(3/892) Containing health costs in the Americas.

In recent years, a series of policy measures affecting both demand and supply components of health care have been adopted in different Latin American and Caribbean countries, as well as in Canada and the United States. In applying these measures various objectives have been pursued, among them: to mobilize additional resources to increase operating budgets; to reduce unnecessary utilization of health services and consumption of pharmaceuticals; to control increasing production costs; and to contain the escalation of health care expenditures. In terms of demand management, some countries have established cost-recovery programmes in an attempt to offset declining revenues. These measures have the potential to generate additional operating income in public facilities, particularly if charges are levied on hospital care. However, only scant information is available on the effects of user charges on demand, utilization, or unit costs. In terms of supply management, corrective measures have concentrated on limiting the quantity and the relative prices of different inputs and outputs. Hiring freezes, salary caps, limitations on new construction and equipment, use of drug lists, bulk procurement of medicines and vaccines, and budget ceilings are among the measures utilized to control production costs in the health sector. To moderate health care expenditures, various approaches have been followed to subject providers to 'financial discipline'. Among them, new reimbursement modalities such as prospective payment systems offer an array of incentives to modify medical practice. Cost-containment efforts have also spawned innovations in the organization and delivery of health services. Group plans have been established on the basis of prepaid premiums to provide directly much or all health care needs of affiliates and their families. The issue of intrasectorial co-ordination, particularly between ministries of health and social security institutions, has much relevance for cost containment. In various countries, large-scale reorganization processes have been undertaken to eliminate costly duplications of resources, personnel, and services that resulted from the multiplicity of providers in the public subsector. Given the pluralistic character of the region's health systems, an important challenge for policy-makers is to find ways to redefine the role of state intervention in health from the simple provision of services to one that involves the 'management' of health care in the entire sector.  (+info)

(4/892) Evidence on the origin of cassava: phylogeography of Manihot esculenta.

Cassava (Manihot esculenta subsp. esculenta) is a staple crop with great economic importance worldwide, yet its evolutionary and geographical origins have remained unresolved and controversial. We have investigated this crop's domestication in a phylogeographic study based on the single-copy nuclear gene glyceraldehyde 3-phosphate dehydrogenase (G3pdh). The G3pdh locus provides high levels of noncoding sequence variation in cassava and its wild relatives, with 28 haplotypes identified among 212 individuals (424 alleles) examined. These data represent one of the first uses of a single-copy nuclear gene in a plant phylogeographic study and yield several important insights into cassava's evolutionary origin: (i) cassava was likely domesticated from wild M. esculenta populations along the southern border of the Amazon basin; (ii) the crop does not seem to be derived from several progenitor species, as previously proposed; and (iii) cassava does not share haplotypes with Manihot pruinosa, a closely related, potentially hybridizing species. These findings provide the clearest picture to date on cassava's origin. When considered in a genealogical context, relationships among the G3pdh haplotypes are incongruent with taxonomic boundaries, both within M. esculenta and at the interspecific level; this incongruence is probably a result of lineage sorting among these recently diverged taxa. Although phylogeographic studies in animals have provided many new evolutionary insights, application of phylogeography in plants has been hampered by difficulty in obtaining phylogenetically informative intraspecific variation. This study demonstrates that single-copy nuclear genes can provide a useful source of informative variation in plants.  (+info)

(5/892) Detection of an archaic clone of Staphylococcus aureus with low-level resistance to methicillin in a pediatric hospital in Portugal and in international samples: relics of a formerly widely disseminated strain?

Close to half of the 878 methicillin-resistant Staphylococcus aureus (MRSA) strains recovered between 1992 and 1997 from the pediatric hospital in Lisbon were bacteria in which antibiotic resistance was limited to beta-lactam antibiotics. The other half were multidrug resistant. The coexistence of MRSA with such unequal antibiotic resistance profiles prompted us to use molecular typing techniques for the characterization of the MRSA strains. Fifty-three strains chosen randomly were typed by a combination of genotypic methods. Over 90% of the MRSA strains belonged to two clones: the most frequent one, designated the "pediatric clone," was reminiscent of historically "early" MRSA: most isolates of this clone were only resistant to beta-lactam antimicrobials and remained susceptible to macrolides, quinolones, clindamycin, spectinomycin, and tetracycline. They showed heterogeneous and low-level resistance to methicillin (MIC, 1.5 to 6 microg/ml), carried the ClaI-mecA polymorph II, were free of the transposon Tn554, and showed macrorestriction pattern D (clonal type II::NH::D). The second major clone was the internationally spread and multiresistant "Iberian" MRSA with homogeneous and high-level resistance to methicillin (MIC, >200 microg/ml) and clonal type I::E::A. Surprisingly, the multidrug-resistant and highly epidemic Iberian MRSA did not replace the much less resistant pediatric clone during the 6 years of surveillance. The pediatric clone was also identified among contemporary MRSA isolates from Poland, Argentina, The United States, and Colombia, and the overwhelming majority of these were also associated with pediatric settings. We propose that the pediatric MRSA strain represents a formerly widely spread archaic clone which survived in some epidemiological settings with relatively limited antimicrobial pressure.  (+info)

(6/892) New World hantaviruses.

Since the initial description in 1993 of hantavirus pulmonary syndrome and its novel aetiological agent, Sin Nombre virus, our knowledge of the epidemiology of New World hantaviruses has continued to evolve. After the identifying outbreak in the southwestern US, four hantaviruses have been identified in North America with specific rodent hosts and associated with a number of sporadic cases. This stability of case recognition in North America is in contrast to the multiple outbreaks and endemic cases in South America. Despite a plethora of New World hantaviruses and new evidence of person-to-person transmission, the ecological and personal determinants of this human infection remain a mystery.  (+info)

(7/892) Impact of maternal nativity on the prevalence of diabetes during pregnancy among U.S. ethnic groups.

OBJECTIVE: This study examines the impact of maternal nativity (birthplace) on the overall prevalence of diabetes during pregnancy and among 15 racial and ethnic groups in the U.S. RESEARCH DESIGN AND METHODS: Birth certificate data for all resident single live births in the U.S. from 1994 to 1996 were used to calculate reported diabetes prevalence during pregnancy and to assess the impact of maternal birthplace outside of the 50 states and Washington, DC, on the risk of diabetes before and after adjustment for differences in maternal age, other sociodemographic characteristics, and late or no initiation of prenatal care overall and for each racial and ethnic group. RESULTS: Mothers born outside of the U.S. are significantly more likely to have diabetes during pregnancy. The impact of maternal nativity on diabetes prevalence is largely explained by the older childbearing age of immigrant mothers. However, adjusted diabetes risk remains elevated for Asian-Indian, non-Hispanic black, Filipino, Puerto Rican, and Central and South American mothers who were born outside the U.S. Conversely, birthplace outside the U.S. significantly reduces diabetes risk for Japanese, Mexican, and Native American women. CONCLUSIONS: Identification, treatment, and follow-up of immigrant mothers with diabetes during pregnancy may require special attention to language and sociocultural barriers to effective care. Systematic surveillance of the prevalence and impact of diabetes during pregnancy for immigrant and nonimmigrant women, particularly in racial and ethnic minority groups, and more detailed studies on the impact of acculturation on diabetes may increase understanding of the epidemiology of diabetes during pregnancy in our increasingly diverse society.  (+info)

(8/892) Population structure of the primary malaria vector in South America, Anopheles darlingi, using isozyme, random amplified polymorphic DNA, internal transcribed spacer 2, and morphologic markers.

A genetic and morphologic survey of Anopheles darlingi populations collected from seven countries in Central and South America was performed to clarify the taxonomic status of this major malaria vector species in the Americas. Population genetics was based on three techniques including isozyme, random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR), and internal transcribed spacer 2 (ITS2) markers. The results of the isozyme analysis indicated moderate differences in the allele frequencies of three putative loci (glutamate oxalaoacetate transaminase-1, isocitrate dehydrogenase-1, and phosphoglucomutase) of the 31 analyzed. No fixed electromorphic differences separated the populations of An. darlingi, which showed little genetic divergence (Nei distances = 0.976-0.995). Fragments produced by RAPD-PCR demonstrated evidence of geographic partitioning and showed that all populations were separated by small genetic distances as measured with the 1 - S distance matrix. The ITS2 sequences for all samples were identical except for four individuals from Belize that differed by a three-base deletion (CCC). The morphologic study demonstrated that the Euclidean distances ranged from 0.02 to 0.14, with the highest value observed between populations from Belize and Bolivia. Based on these analyses, all the An. darlingi populations examined demonstrated a genetic similarity that is consistent with the existence of a single species and suggest that gene flow is occurring throughout the species' geographic range.  (+info)