During May 1998, we conducted a case-control study of 357 participants from 60 households during an outbreak of acute bartonellosis in the Urubamba Valley, Peru, a region not previously considered ...endemic for this disease. Blood and insect specimens were collected and environmental assessments were done. Case-patients (n = 22) were defined by fever, anemia, and intra-erythrocytic coccobacilli seen in thin smears. Most case-patients were children (median age = 6.5 years). Case-patients more frequently reported sand fly bites than individuals of neighboring households (odds ratio OR = 5.8, 95% confidence interval CI = 1.2-39.2), or members from randomly selected households > or = 5 km away (OR = 8.5, 95% CI = 1.7-57.9). Bartonella bacilliformis isolated from blood was confirmed by nucleotide sequencing (citrate synthase g/tA, 338 basepairs). Using bacterial isolation (n = 141) as the standard, sensitivity, specificity, and positive predictive value of thin smears were 36%, 96%, and 44%, respectively. Patients with clinical syndromes compatible with bartonellosis should be treated with appropriate antibiotics regardless of thin-smear results.
Evidence that domestic dogs may act as reservoir hosts for cutaneous leishmaniasis in the Peruvian Andes is provided by the isolation, for the first time, from naturally infected dogs of parasites ...identified (by isoenzymes) as
Leishmania peruviana.
Leishmania parasites were isolated from nasal aspirates or biopsies from 5 (1·8%) of 279 asymptomatic dogs sampled in endemic villages of the Peruvian Andes. In addition,
Leishmania (Viannia) infections were identified in 15 (5·4%) of 276 nasal samples by the polymerase chain reaction (PCR) using subgenus-specific primers. Further circumstantial evidence for a reservoir role for dogs comes from the finding of a relatively high dog blood index among the sandfly vectors collected inside houses (29% for
Lutzomyia peruensis and 17% for
Lu. verrucarum). Possible wild mammal reservoir hosts for Andean cutaneous leishmaniasis were also detected in endemic villages. At least 8 species were identified among the 1266 small mammals trapped.
Leishmania parasites were isolated from blood or skin biopsies taken from 2 (2·6%) of 78
Didelphis albiventris and 6 (1·2%) of 511
Phyllotis andinum. Three isolates were identified by isoenzymes as
L. peruviana, and the other 5 were identified by PCR as
Leishmania (Viannia) species.
Leishmania (Viannia) infections were also identified by PCR directly on skin biopsies taken from 2 (2·8%) of 72
D. albiventris, 1 (0·2%) of 499
P. andinum, and 4 (2·6%) of 153
Akodon sp.
Objectives To determine the relative bioavailability of the estrogenic components of a generic brand of conjugated estrogens marketed in Chile in comparison to that of Conpremin* (Premarin* in the ...United States).
Methods A randomized cross-over study was conducted on 16 healthy postmenopausal women receiving single oral doses of either two Conpremin 0.625-mg tablets or two 0.625-mg tablets of the generic brand, with a 14-day wash-out interval between doses. A gas chromatography tandem mass spectrometry assay was used to determine estrogen components.
Results The peak plasma concentrations of unconjugated and total estrone and equilin, unconjugated 17β-dihydroequilin and 17β-estradiol were higher and occurred earlier with the generic conjugated estrogens than with Conpremin. The 90% confidence limits for both variables lay outside the accepted bioequivalence limits of 80-125%. Additionally, no measurable plasma concentration of unconjugated Δ8-9-dehydroestrone or 17 β-Δ8-9-dehydroestradiol was seen after administration of the generic conjugated estrogens.
Conclusions These pharmacokinetic results indicate that the generic tablets do not have the modified-release characteristics of Conpremin tablets. In addition, the absence of Δ8-9-dehydroestrone and 17β-Δ8-9-dehydroestradiol in the plasma indicates that the generic form is not compositionally equivalent to Conpremin.
A two-year field study of Andean cutaneous leishmaniasis (uta) in the valley of Purisima, Ancash Department, Peru has provided quantitative epidemiologic and entomologic evidence for the predominant ...role of Lutzomyia peruensis in the transmission of Leishmania peruviana in this endemic area. The monthly incidence in the valley was greatest in the wet season (from December to May), when Lu. peruensis was particularly endophilic. A significant correlation was detected between intradomiciliary (but not extradomiciliary) Lu. peruensis abundance and the monthly incidence of uta in the valley following a one-month time lag. In contrast, no significant correlation was detected between any measure of Lu. verrucarum abundance and the incidence of uta. Lutzomyia peruensis and Lu. verrucarum comprise more than 98% of all the sand fly captures made in this valley. The increase in incidence of uta with altitude, which reached a peak rate between 2,250 and 2,750 meters above sea level, was associated with an increase in the relative abundance of Lu. peruensis as compared with Lu. verrucarum. Seasonal and altitudinal variation was also detected in the peak time of activity for both sand fly species, a phenomenon that could significantly influence the transmission rate: later host-seeking sand flies being more likely to find sleeping, nondefensive, human hosts.
Risk factors for cutaneous leishmaniasis were identified from a comparative study of transmission rates in 27 villages in the Departments of Lima, Ancash, and Piura in Peru. To evaluate regression ...analysis as a tool for the incrimination of sand fly vectors in the absence of other biologic evidence, univariate and multivariate logistic regression analyses were used to identify which of 14 variables (the abundance of nine sand fly species, four social factors, and region) predicted transmission rates in villages (incidence, active prevalence, or cumulative prevalence). In general, suspected or proven vectors (e.g., Lutzomyia peruensis) had the strongest associations with transmission rate, indicating that regression is a useful supplementary method of incriminating vectors. Regression was then used to quantify the importance of suspected risk factors. Transmission rate increased with the abundance of Lu. peruensis, Lu. ayacuchensis, Lu. noguchii, and, to a lesser extent, Lu. verrucarum and transmission was higher among villagers who slept more frequently in temporary shelters in crop areas. There were also weak effects of the number of dogs/ person (negative) and the number of persons/household (positive). Linear regressions failed to detect a threshold sand fly density below which transmission ceases. The minimal adequate multiple regression model explained 82% of the variance in village incidence rates. This model was used to predict the effect on incidence of reducing each of the four suspected vectors in northern and southern Peru. The results indicate that vector control programs in the south should aim at Lu. peruensis, Lu. verrucarum, and Lu. noguchii, but focus on Lu. ayacuchensis in the north.
The oxidation of low-density lipoprotein (LDL) is an important factor in the development of atherosclerosis. The antioxidant activity of some compounds buffers the free radicals generated either ...endogenously or exogenously, thus decreasing the potential damage mediated by oxidation. Estrogens are potent antioxidants of LDL, in vitro and in vivo, a mechanism that could probably influence the cardioprotection associated with hormone replacement therapy in postmenopause. We conducted an in vitro study of the antioxidant effect on LDL of two selective estrogen receptor modulators, raloxifene (RLX) and tamoxifen (TMX), comparing them with the known antioxidant effect of estradiol (E2 ).
LDL was isolated by ultracentrifugation from plasma obtained from 12 healthy, untreated, postmenopausal women. Aliquots containing 0.5 mg of LDL protein were incubated for 4 h with CuSO4 (15 micro M) to induce oxidative stress and with one of the three compounds studied: RLX, TMX, or E2 at doses of 0, 1, 2, 3, 5, 15, 50, and 500 micro M, and 1 and 2 mM. Malonaldehyde (MDA, nmol/mg protein) was measured as a marker of LDL oxidation.
E2 induced a dose-dependent decrease in MDA concentration. MDA values decreased significantly, as compared with baseline, starting at a concentration of 2 micro M for RLX and 3 micro M for both, TMX, or E2. The dose necessary to reduce the generation of MDA by 50% was significantly lower for RLX (3.3 micro M, < 0.001) than for E2 (24.6 micro M ) or TMX (35.3 micro M). The area under the curve also showed a higher antioxidant activity for RLX compared with TMX or E2 ( < 0.001).
The in vitro antioxidant activity of RLX is substantially more potent than TMX or E2. This finding, added to the other beneficial effects of the drug in the cardiovascular system, could imply some cardioprotector effect.
A study was carried out in the Peruvian Andes to test the suitability of CDC light traps for monitoring changes in the human-landing rate of endophagic phlebotomine sandflies, following ...house-spraying with pyrethroid insecticide. On four pairs of consecutive nights, sandflies were caught inside eight sprayed and eight unsprayed houses, either by human bait or by CDC light traps. The sandflies collected were Lutzomyia verrucarum (97%) and Lu. peruensis (3%), both probable vectors of Leishmania peruviana, and the species composition was unaffected by house-spraying. A non-linear relationship was detected between light-trap and human-bait catches, but the relationship did not diverge significantly from linearity within the range of sandfly abundance found in most houses in the endemic area (i.e. between 3 and 200 sandflies/house-night), and did not differ significantly between sprayed and unsprayed houses. However, light trap catches had a significantly lower proportion of blood-fed females in sprayed than in unsprayed houses, probably due to an insecticidal effect on post-blood-feeding behaviour. The proportion of Lu. verrucarum was significantly higher in light trap than in human bait catches, indicating that Lu. peruensis is either more anthropophilic or less phototropic than Lu. verrucarum.
Background Phytoestrogens are a family of plant-derived compounds with weak estrogenic and antiestrogenic properties. The antioxidant capacity of phytoestrogens has been proposed as one of the ...important mechanisms that explain their health benefits.
Objective To determine the in vitro potency of three phytoestrogens, ubiquitous in food, (biochanin A, daidzein and genistein) as antioxidants of low density lipoprotein (LDL) and to compare them with the well-established antioxidant actions of estradiol and quercetin, an ubiquitous flavonoid which is found in high concentration in onions, tea and berries.
Methods LDL was isolated by ultracentrifugation from the plasma of ten healthy postmenopausal women who were not on hormone therapy. Aliquots containing 0.5 mg of protein were incubated for 4 h with CuSO4 15 μmol/l to induce oxidative stress and with one of the five compounds studied: estradiol, quercetin, biochanin A, daidzein, and genistein, in doses of 0, 5, 15, 50, 500, 1000 and 2000 μmol/l. In addition, we studied the combined effect of estradiol 1 μmol/l plus quercetin 1 μmol/l, comparing their antioxidant action with that of each compound separately. Malonaldehyde (MDE nmol/mg protein) was measured as a marker of LDL oxidation.
Results Estradiol and quercetin induced a dose-dependent decrease in MDE concentration (p < 0.01). Comparing the areas under the curve, the antioxidant effect of quercetin was 8 times higher than the one observed with estradiol (p < 0.01). A 50% decrease in MDE was reached by quercetin at a concentration of 3.4 μmol/l, estradiol at 29 μmol/l, genistein at 280 μmol/l, biochanin at 1312 mmol/l and daidzein at 8007 mmol/l. Estradiol 1 μmol/l and quercetin 1 μmol/l did not modify MDE generation separately, but, when incubated combined, there was a significant decrease of MDE (p < 0.02).
Conclusion The phytoestrogens studied showed a weak antioxidant activity in vitro. The flavonoid quercetin, in contrast, showed the most potent antioxidant activity in vitro, higher than estradiol. Estradiol and quercetin showed additive antioxidant activity. We speculate that different compounds with variable antioxidant effects could amplify their antioxidant capacity when acting combined.
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