The transmission of Leishmania infantum chagasi by the bite of the Lutzomyia longipalpis to two different vertebrates

<p>Abstract</p> <p>Background</p> <p>Sandflies are vectors of <it>Leishmania</it>, the causative agent of leishmaniasis in mammalian hosts, including humans. The protozoan parasite is transmitted by the sandfly bite during salivation that occurs at the moment of blood feeding. The components of vector saliva include anticlotting and vasodilatory factors that facilitate blood flow and immunomodulatory factors that inhibit wound healing and quell the immune response. Not surprisingly, these factors also play important roles in the establishment of <it>Leishmania </it>infection. To date, the majority of knowledge that has been generated regarding the process of <it>Leishmania </it>infection, including <it>L. infantum chagasi </it>transmission has been gathered by using intradermal or subcutaneous inoculation of purified parasites.</p> <p>Findings</p> <p>This study presents the establishment of a transmission model of <it>Leishmania infantum chagasi </it>by the bite of <it>Lutzomyia longipalpis</it>, the vector of American visceral leishmaniasis. The parasites were successfully transmitted by infected sandfly bites to mice and hamsters, indicating that both animals are good experimental models. The <it>L. infantum chagasi </it>dose that was transmitted in each single bite ranged from 10 to 10, 000 parasites, but 75% of the sandflies transmitted less than 300 parasites.</p> <p>Conclusions</p> <p>The strategy for initiating infection by sandfly bite of experimental animals facilitates future investigations into the complex and dynamic mechanisms of visceral leishmaniasis. It is important to elucidate the transmission mechanism of vector bites. This model represents a useful tool to study <it>L. infantum chagasi </it>infection transmitted by the vector.</p

Correlation between endometrial dating of luteal phase days 6 and 10 of the same menstrual cycle

CONTEXT: Endometrial maturation, important in the diagnosis of infertile couples, has been evaluated since 1950 using the Noyes criteria. Nevertheless, there is no consensus regarding the most suitable period of the luteal phase for performing the biopsy. OBJETIVE: This study evaluated the correlation between the histological dating of two endometrial biopsies performed in the same menstrual cycle, on luteal phase days six and ten.DESIGN: Prospective study. SETTING: Human Reproduction Division of the Federal University of São Paulo, referral center. PATIENTS:Twenty-five women complaining of infertility had their menstrual cycles monitored by ultrasound and LH plasma levels, to obtain evidence of ovulation. PROCEDURES: Endometrial biopsies were performed on luteal phase days LH+6 and LH+10 (luteal phase day 1 = LH+1 = the day that follows LH peak). Dating was done according to morphometric criteria, in which an endometrium sample is considered out of phase if the minimum maturation delay is one day. On day LH+6, blood was drawn for plasma progesterone level determination. RESULTS: All patients had an ovulatory cycle (mean LH peak: 47.4 U/L; mean follicular diameter on LH peak day: 18.9 mm; mean endometrial thickness on LH peak day: 10.3 mm; mean plasma progesterone level on day LH+6: 14.4 ng/ml). 14 patients had both biopsies in phase; 5 patients had out of phase biopsies only on day LH+6; 3 had out of phase biopsies only on day LH+10 and 3 patients had out of phase biopsies on both days. McNemar's test showed no statistical difference between these data (p>33.36%). CONCLUSIONS: The correlation found between the endometrial datings suggests that biopsies performed on either of these two days are suitable for evaluation of endometrial maturation.CONTEXTO: A verificação da maturidade endometrial, elemento diagnóstico necessário na avaliação do casal com queixa de infertilidade, vem sendo feita desde 1950 através do critério de datação histológica de Noyes. No entanto, não existe um consenso em relação ao período da fase lútea mais adequado para a colheita. OBJETIVO: Avaliar a correlação entre as datações histológicas de duas amostras de endométrio colhidas nos dias 6 e 10 da fase lútea de um mesmo ciclo menstrual. LOCAL: Setor de Reprodução Humana da Universidade Federal de São Paulo (UNIFESP). TIPO DE ESTUDO: Estudo prospectivo. Constou da comparação entre duas datações de endométrio num mesmo ciclo menstrual. PARTICIPANTES: 25 pacientes com queixa de infertilidade tiveram um ciclo menstrual monitorizado por ultra-sonografia e medida plasmática de LH, para demonstração de ovulação. PROCEDIMENTO: Biópsias de endométrio foram feitas nos dias LH+6 e LH+10 da fase lútea, considerando-se o dia seguinte ao do pico de LH como LH+1. A datação foi feita de acordo com critério morfométrico, considerando-se o endométrio como fora de fase, se o atraso de maturação mínimo fosse de um dia. No dia LH+6 foi feita dosagem de progesterona plasmática. RESULTADOS: Todas as pacientes apresentaram ciclos ovulatórios (média dos valores de pico de LH: 47,3 U/L; média dos diâmetros foliculares no dia do pico de LH: 18,9 mm; média das espessuras do endométrio no dia do pico de LH: 10,3 mm; média das concentrações de progesterona plasmática no dia LH+6: 14,4 ng/ml.). Em 14 pacientes, as duas biópsias estavam em fase. Houve atraso de maturação apenas no dia LH+6 em cinco pacientes; apenas no dia LH+10 em três pacientes e, nos dois dias, em três pacientes. Não houve diferença estatística entre esses valores (teste de McNemar, p=33,36%). CONCLUSÕES: Os resultados sugerem que a colheita do endométrio em qualquer dos dias (sexto ou décimo) da fase lútea fornece resultados semelhantes em relação à maturidade endometrial.Universidade Federal de São Paulo (UNIFESP)UNIFESPSciEL

Инфекционная составляющая и иммунопатология при хронических воспалительных заболеваниях слизистой оболочки гастродуоденальной области

Выявлено коинфицирование слизистой оболочки желудочно−кишечного тракта Helicobacter pylori и вирусами группы герпеса у больных хроническим гастритом, язвенной болезнью желудка и двенадцатиперстной кишки. Проведена оценка общих и специфических иммунных реакций организма на указанные инфекционные агенты. Обнаруженные изменения в клеточном и гуморальном звене иммунитета могут свидетельствовать об обусловленном ими системном иммунопатологическом процессе.Co−infection of the gastrointestinal mucosa with Helicobacter pylori and herpes viruses in patients with chronic gastritis, gastric and duodenal ulcer was revealed. General and specific immune reactions of the organism to the above agents were evaluated. The revealed changes in the cellular and humoral immunity can suggest systemic immunopathological process

Quantification of Leishmania infantum DNA in females, eggs and larvae of Rhipicephalus sanguineus

<p/> <p>Background</p> <p><it>Leishmania infantum </it>is a widespread parasite that affects dogs and humans worldwide. It is transmitted primarily by phlebotomine sand flies, but recently there has been much discussion on the role of the brown dog tick, <it>Rhipicephalus sanguineus</it>, as a potential vector for this protozoan. Recent laboratory and field investigations have contributed to this hypothesis, but a proof of the vector capacity of <it>R. sanguineus </it>has yet to be provided. Following a recent study suggesting that <it>L. infantum </it>passes transovarially from the female tick to her progeny the current study provides new evidence of the transovarial transmission of <it>L. infantum </it>in <it>R. sanguineus</it>.</p> <p>Methods</p> <p>Engorged females of <it>R. sanguineus </it>were collected from the environment in a dog shelter of southern Italy, where canine leishmaniosis is endemic. In the laboratory, 97 females that successfully laid eggs, their eggs and the originated larvae were subjected to DNA extraction and then tested by a TaqMan-based real time PCR targeting a fragment of the kinetoplast DNA (kDNA) of <it>L. infantum</it>.</p> <p>Results and conclusions</p> <p><it>L. infantum </it>kDNA was detected in engorged females, their eggs and originating larvae, with a parasite load ranging from 1.8 × 10^-4to 10.0 × 10⁰. Certainly, the current study provides further evidence on the passage of <it>L. infantum </it>from <it>R. sanguineus </it>females to their offspring. The observation of promastigote forms in larvae is necessary to definitively confirm this hypothesis, which would raise interesting questions about the possible role of ticks in the maintenance of <it>L. infantum </it>infection among dogs in certain areas.</p

The Evolution of Compact Binary Star Systems

We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Binary NSs and BHs are thought to be the primary astrophysical sources of gravitational waves (GWs) within the frequency band of ground-based detectors, while compact binaries of WDs are important sources of GWs at lower frequencies to be covered by space interferometers (LISA). Major uncertainties in the current understanding of properties of NSs and BHs most relevant to the GW studies are discussed, including the treatment of the natal kicks which compact stellar remnants acquire during the core collapse of massive stars and the common envelope phase of binary evolution. We discuss the coalescence rates of binary NSs and BHs and prospects for their detections, the formation and evolution of binary WDs and their observational manifestations. Special attention is given to AM CVn-stars -- compact binaries in which the Roche lobe is filled by another WD or a low-mass partially degenerate helium-star, as these stars are thought to be the best LISA verification binary GW sources.Comment: 105 pages, 18 figure