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S Valle

Publications and source records attributed to S Valle.

13 recordsLinked to original sources
PubMed2004

Use of IgG Avidity test in case definitions of toxoplasmosis in pregnancy.

A survey network for congenital toxoplasmosis (TOXO-NET) was set up in December 1996 in Piedmont (Italy). Participants were asked to classify the infections in pregnant mothers and newborns by the criteria of the European Network on Congenital Toxoplasmosis published by Lebech in 1996. Because the IgG Avidity test is largely employed as a 2nd level test in toxoplasmosis diagnosis and it could be helpful to date infection, the co-ordinators of TOXO-NET suggested including it in the "case definition" of "probable" infection and "unlikely" infection. 117 cases of toxoplasmosis in pregnancy divided into the risk categories under Lebech's criteria were re-examined using the "new" case definitions. 77 out of 117 (65.8%) Toxoplasma gondii infections during pregnancy could be defined with only one serum sample using the IgG Avidity test. The IgG Avidity test proved a useful method to classify the Toxoplasma gondii infections in pregnancy, especially when we had only one serum sample.

Animals↗
PubMed1999

Widespread atypical cutaneous Leishmaniasis caused by Leishmania (L.) Chagasi in Nicaragua.

Leishmania chagasi, the causative agent of visceral leishmaniasis (VL) in the Americas, has recently been associated with atypical cutaneous leishmaniasis (ACL) in Central America; however, little comprehensive information about this disease is available. Clinical, epidemiologic, and parasitologic characteristics of 252 ACL cases and 44 VL cases in Nicaragua were analyzed. Visceral leishmaniasis is primarily associated with malnourished children less than five years of age, whereas ACL is found predominantly in children greater than five years of age and young adults. Genetically similar parasites are associated with both disease manifestations. The sand fly Lutzomyia evansi, in addition to Lu. longipalpis, may be involved in transmission of L. chagasi to humans. Our results indicate that ACL is more prevalent than previously thought, affecting up to 10% of a local population. The fact that the same parasite appears to cause both ACL and the potentially fatal visceral disease suggests that the host immune response is critical in determining the outcome of L. chagasi infection. The public health implications of the wide-spread presence of L. chagasi are discussed.

Animals↗
PubMed1998

Genetic variability among populations of the sand fly Lutzomyia (Lutzomyia) longipalpis (Diptera: Psychodidae) from Central America.

Eleven Central American populations of Lutzomyia longipalpis (Lutz & Neiva) were analyzed for genetic variation at 16 enzyme loci. The aim was to study the genetic structure among populations within this region and to identify demes that may represent different sibling species. Genotypic frequencies within populations agreed with Hardy-Weinberg expectations, indicating that there were no sympatric sibling species among these 11 populations. Levels of genetic distance between pairs of populations were very low (< 0.02). Some substructing was evident, because after genotypes of all populations mere pooled, 7 of the 16 enzyme loci deviated from Hardy-Weinberg expectations. Estimates of effective migration rates among populations (Nm) were low (3.7), indicating that gene flow was restricted. These data explained observed genetic substructuring when all genotypes were pooled.

Animals↗
PubMed1998

Typing of dengue viruses in clinical specimens and mosquitoes by single-tube multiplex reverse transcriptase PCR.

In recent years, dengue viruses (serotypes 1 to 4) have spread throughout tropical regions worldwide. In many places, multiple dengue virus serotypes are circulating concurrently, which may increase the risk for the more severe form of the disease, dengue hemorrhagic fever. For the control and prevention of dengue fever, it is important to rapidly detect and type the virus in clinical samples and mosquitoes. Assays based on reverse transcriptase (RT) PCR (RT-PCR) amplification of dengue viral RNA can offer a rapid, sensitive, and specific approach to the typing of dengue viruses. We have reduced a two-step nested RT-PCR protocol to a single-tube reaction with sensitivity equivalent to that of the two-step protocol (1 to 50 PFU) in order to maximize simplicity and minimize the risk of sample cross-contamination. This assay was also optimized for use with a thermostable RT-polymerase. We designed a plasmid-based internal control that produces a uniquely sized product and can be used to control for both reverse transcription or amplification steps without the risk of generating false-positive results. This single-tube RT-PCR procedure was used to type dengue viruses during the 1995 and 1997-1998 outbreaks in Nicaragua. In addition, an extraction procedure that permits the sensitive detection of viral RNA in pools of up to 50 mosquitoes without PCR inhibition or RNA degradation was developed. This assay should serve as a practical tool for use in countries where dengue fever is endemic, in conjunction with classical methods for surveillance and epidemiology of dengue viruses.

Aedes↗
PubMed1995

[Phlebotomines of Nicaragua. II. Description of Lutzomyia legerae n. sp. (Diptera:Psychodidae)].

Both sexes of Lutzomyia legerae n. sp., a new species of phlebotomine sand fly belonging to the subgenus Lutzomyia, cruciata complex, are described from specimens collected in peridomestic environment, by light-trap, in central Nicaragua. Females of the new species are very close to L. cruciata. Therefore, in the leishmaniasis foci where the two species occur sympatrically implication of each species as a vector has to be carefully investigated.

Animals↗
PubMed1982

A combination Verhoeff's elastic and Masson's trichrome stain for routine histology.

A method for the combined staining of elastic, muscle and connective tissue for routine use in histopathology is described. The elastica, stained black by Verhoeff's technique, is contrasted with the muscle and connective tissue stained red and green or blue respectively by a modification of Masson's trichrome. Cell nuclei stain blue-black with Weigert's iron hematoxylin. The procedure takes approximately two hours and is most suitable for the study of vascular pathology in surgical and autopsy sections.

Connective Tissue↗
PubMedDate not supplied

[Transgenics without Manichaeism].

We live in an era characterized by the hegemony of science and technology, an era fraught with questions awaiting answers which would enable a safe and sustainable future for humankind. The development of agro-industrial processes - food products in particular - through recombinant DNA technology has enhanced the profit prospects of the few big biotechnology companies and of large-scale farmers who have access to the latest technological developments. We thus oppose a moratorium on recombinant DNA technology. Moreover, hasty statements about risk-free transgenics may be misleading in the absence of extensive safety tests. There is a pressing need for the establishment of biosafety policy in this country involving the organized civil society and every government agency responsible for monitoring such matters. There is also the need to put in place a bio-surveillance and a code of ethics regarding genetic manipulation.

Biotechnology↗
PubMedDate not supplied

[Streptococcus agalactiae in pregnant women. Prevalence at the Posadas Hospital].

Streptococcus agalactiae (Lancefield group B Streptococcus), is the most frequent microorganism involved in neonatal infections through the mother-fetus vertical transmission. It is also responsible for infections in pregnant women, and adults with underlying diseases. The objective of this work was to know the S. agalactiae carrier prevalence in pregnant women who attended to Posadas Hospital, and to study the susceptibility pattern of the isolates to penicillin, erythromycin and clindamycin. From 1203 pregnant women studied, S. agalactiae was recovered in 113, which means a prevalence of 9.39%. Antimicrobial susceptibility was tested to 87 isolates. All of them were susceptible to penicillin, and only 2 isolates were resistant to erythromycin and clindamycin (constitutive MLS mechanism). We emphasize the importance of knowing these last resistance, in the case of beta-lactam antibiotics allergic women.

Adolescent↗
PubMedDate not supplied

[Colorectal cancer screening: survey of endoscopy center's physicians in Lazio region].

The aim of the present work is to describe the characteristics of digestive endoscopy centers and the physicians that work there, with particular attention to their attitudes and practices in colorectal cancer screening. A questionnaire was sent to all 80 digestive endoscopy centers in the Lazio region, identified by the annual census of Italian Society of Digestive Endoscopy (Società Italiana di Endoscopia Digestiva, SIED). Seventy-one centers (89%), returned the questionnaire. Screening activity on average represents 14% of the centers' colonoscopy workload. Colonoscopy was considered to be a "very effective" screening test by 96% of physicians, the faecal occult blood test "very effective" by 20%, and flexosigmoidoscopy "very effective" by 11%. Ninety-seven percent (97%) of physicians reported recommending any test for screening: 80% colonoscopy, 61% faecal occult blood test, 14% double contrast barium enema and 11% flexosigmoidoscopy. Despite the fact that almost all physicians reported recommending screening, the centres are only marginally involved in screening practice. Endoscopy centers' physicians tend to have an aggressive strategy for colorectal cancer prevention and exclusive trust in colonoscopy; an attitude more consistent with a clinical-diagnostic approach than with real mass screening of a healthy population.

Adult↗