Coronary magnetic resonance angiography for assessment of the stent lumen: a phantom study.

PURPOSE: To evaluate the feasibility of visualizing the stent lumen using coronary magnetic resonance angiography in vitro. MATERIAL AND METHODS: Nineteen different coronary stents were implanted in plastic tubes with an inner diameter of 3 mm. The tubes were positioned in a plastic container filled with gel and included in a closed flow circuit (constant flow 18 cm/sec). The magnetic resonance images were obtained with a dual inversion fast spin-echo sequence. For intraluminal stent imaging, subtraction images were calculated from scans with and without flow. Subsequently, intraluminal signal properties were objectively assessed and compared. RESULTS: As a function of the stent type, various degrees of in-stent signal attenuation were observed. Tantalum stents demonstrated minimal intraluminal signal attenuation. For nitinol stents, the stent lumen could be identified, but the intraluminal signal was markedly reduced. Steel stents resulted in the most pronounced intraluminal signal voids. CONCLUSIONS: With the present technique, radiofrequency penetration into the stents is strongly influenced by the stent material. Thesefindings may have important implicationsforfuture stent design and stent imaging strategies.

Development of Ascaris lumbricoides eggs from females eliminated after chemotherapy in man

The development of Ascaris lumbricoides eggs obtained from females eliminated after treatment of infected individuals with a single oral dose of the antihelminthic drugs thiabendazole (50 mg/kg - 33 patients) or levamisole (250 mg - independent of body weigth - 20 patients) was studied. Every female eliminated up to 72 h after treatment were dissected, the uterus isolated and sectioned into small fragments. The eggs were transferred to plastics tubes and incubated at 28 degrees centigrades in 0.1 N H2 SO4 for 100 days. Every 20 days, starting from the 20 th up to the 100 th day, the extent of egg embryonation ratio was determined. The culture of A. lumbricoides eggs obtained from females from patients treated with thiabendazole did not contain embryonated eggs until the final period of observation. In contrast, the eggs obtained from females eliminated by patients treated with levamisole (control) presented an embryonation rate of 0.0 - 98.0% in the same period.

New methods for the diagnosis of Babesia bigemina infection

Accurate diagnosis of Babesia bigemina infection, an economically important tick-transmitted protozoan parasite of cattle, is essential in the management of disease control and in epidemiological studies. The currentlyused methods of diagnosis are blood smear examination and serological tests which include agglutination and immunofluorescence tests. These testes have been used the fild but because they lack sensitivity and specificity, never and improved methods of diagnosis are being developed. The quantitative buffy coat (OBC) method, using microhaematocrit tubes and acridine orange staining allows rapid and quicker diagnosis of B. bigemina and other blood parasites compared to light microscopic examination of stained smears. Parasite specific monoclonal antibodies have been used in antigen/antibody capture enzymelinked immunosorbent assays with grater sensitivity and specificity than previously described serological tests. Similary, DNA probes, derived from a repetitive sequence of the B. bigemina genome, offer a method of detecting very small numbers of parasites which are undetectable by conventional microscopy. An extrachromosomal DNA element, present in all the tick-borne protozoan parasites so far tested, provides an accurate means of diferentiating mixed parasite populations in infected animals. These improved methods will greatly facilitate epidemiological studies.

Why are slip lengths so large in carbon nanotubes?

The enhanced flow in carbon nanotubes is explained using a mathematical model that includes a depletion layer with reduced viscosity near the wall. In the limit of large tubes the model predicts no noticeable enhancement. For smaller tubes the model predicts enhancement that increases as the radius decreases. An analogy between the reduced viscosity and slip-length models shows that the term slip-length is misleading and that on surfaces which are smooth at the nanoscale it may be thought of as a length-scale associated with the size of the depletion region and viscosity ratio. The model therefore provides a physical interpretation of the classical Navier slip condition and explains why `slip-lengths' may be greater than the tube radius.

Diagnosis of malaria by acridine orange fluorescent microscopy in an endemic area of Venezuela

Fluorescent (acridine orange) microscopical examination of capillary centrifuged blood (quantitative buffy coat [QBC®] analysis) and Giemsa stained thick blood smears (GTS) were compared for diagnosis of malaria in blood specimens from adults living in malaria transmission areas of the States of Bolivar and Amazonas in southeastern and south Venezuela, respectively. Of a total of 198 GTS examined, 95 subjects (48%) showed parasitaemia. Among the 95 blood films with a positive GTS, 94 were judged positive by the QBC. However, positive QBC tubes were found in 29 out of 103 blood specimens with a negative GTS. Thus, relative to a GTS standard, the sensitivity and specificity of the QBC-test was 99.2% and 72%, respectively. Young trophozoites of Plasmodium vivax and P. falciparum could not be distinguished with certainty. It is confirmed that the QBC offers many advantages compared with the standard diagnosis of malaria parasites, specifically in the speed of staining and ease of interpretation. However, in places where P. falciparum and P. vivax occur, species and stage differentiation should be confirmed with the GTS.

Morphology and Histology of the Female Reproductive System of Abedus ovatus Stal (Belostomatidae: Hemiptera: Insecta)

In Abedus ovatus Stal, the female reproductive system consists of a pair of ovaries leading to oviduct and opens out by genital aperture. Each ovary is composed of five telotrophic ovarioles, with four different regions, terminal filament, germarium, vitellarium and pedicel. Germarium and vitellarium are the germ tubes in which the development of oocyte occurs. In the germarium, the differentiation of trophocytes into young oocytes was observed in three zones, ZI, ZII and ZIII. Further development of oocytes in the vitellarium could be divided into seven stages, STI STVII. The developed eggs are lodged in the pedicel

Microautophagy in the yeast Saccharomyces cerevisiae.

Microautophagy involves direct invagination and fission of the vacuolar/lysosomal membrane under nutrient limitation. In Saccharomyces cerevisiae microautophagic uptake of soluble cytosolic proteins occurs via an autophagic tube, a highly specialized vacuolar membrane invagination. At the tip of an autophagic tube vesicles (autophagic bodies) pinch off into thevacuolar lumen for degradation. Formation of autophagic tubes is topologically equivalent to other budding processes directed away from the cytosolic environment, e.g., the invagination of multivesicular endosomes, retroviral budding, piecemeal microautophagy of the nucleus and micropexophagy. This clearly distinguishes microautophagy from other membrane fission events following budding toward the cytosol. Such processes are implicated in transport between organelles like the plasma membrane, the endoplasmic reticulum (ER), and the Golgi. Over many years microautophagy only could be characterized microscopically. Recent studies provided the possibility to study the process in vitro and have identified the first molecules that are involved in microautophagy.

A Possible Role for Rusa Deer (Cervus timorensis russa) and Wild Pigs in Spread of Trypanosoma evansi from Indonesia to Papua New Guinea

Movement of transmigrants and livestock from western Indonesia to southeastern areas of Irian Jaya near the border with Papua New Guinea may pose a risk of introducing Trypanosoma evansi into Papua New Guinea via feral Rusa deer (Cervus timorensis russa) and wild pigs which inhabit these areas in large numbers. Pilot experimental studies were conducted to observe infection in pigs and Rusa deer with a strain of T. evansi isolated in Indonesia. Parasitaemia and signs of clinical disease were monitored each second day for 120 days. Trypanosomes were observed in haematocrit tubes at the plasma-buffy coat interface of jugular blood of deer and pigs on 86% and 37% of sampling occasions respectively. Parasitaemia was at a high level in deer for 35% of the time but for only 11.5% of the time in pigs. Results indicate that both Rusa deer and pigs have a high tolerance for infection with T. evansi. The deer suffered mild anaemia evidenced by a 25% reduction in packed cell volume (PCV) 14 days after infection which coincided with the initial peak in parasitaemia. However, PCV had returned to pre infection values by the end of the experiment. The pigs showed no change in PCV. There were no visual indications of disease in either species and appetite was not noticeably affected. It was concluded that both Rusa deer and pigs were capable reservoir hosts for T. evansi but that Rusa deer, with their more persistent higher levels of parasitaemia, have more potential to spread T. evansi into Papua New Guinea from West Irian than pigs.

Sensitivity of a Vacuum Aspiratory Culture Technique for Diagnosis of Localized Cutaneous Leishmaniasis in an Endemic Area of Leishmania (Viannia) braziliensis Transmission

Sixty eight patients with localized cutaneous leishmaniasis from an area with Leishmania (Viannia) braziliensis transmission had cultures performed with a modified Marzochi´s vacuum aspiratory puncture technique to establish sensitivity and contamination rate with this new method. Overall sensitivity of three aspirates was 47.1%; (CI95% 39.4; 59.4) significantly greater than the sensitivity of a single one aspirate. Fungal contamination was observed in 6/204 (2.9%) inoculated culture tubes. We recommend that this useful technique should be adopted as routine for primary isolation of L. (V.) braziliensis from localized cutaneous ulcers.

Preliminary assays indicate that Antonia ovata (Loganiaceae) and Derris amazonica (Papilionaceae), ichthyotoxic plants used for fishing in Roraima, Brazil, have an insecticide effect on Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae)

Laboratory-reared Lutzomyia longipalpis (Lutz and Neiva 1912) was tested with extracts of two ichthyotoxic plants, known as timbós, used as fishing poison in the Amazon. Phlebotomines, L. longipalpis, and plants, Antonia ovata and Derris amazonica, were collected in the Raposa-Serra do Sol Indian Reserve, a focus of visceral leishmaniasis in the State of Roraima, Brazil. Extracts were prepared from dried leaves of A. ovata and roots of D. amazonica that were percolated in water, filtered and dried out at 50°C. The solid extract obtained was diluted in water at 150, 200 and 250 mg/ml. The solution was blotted in filter paper placed at the bottom of cylindric glass tubes containing sand flies. For each plant extract and dilution, two series of triplicates with 5 male and 5 female specimens of L. longipalpis were used. Mortality was recorded every 2 h during 72 h of exposure. At 72 h the mortality was as high as 80% for extracts of A. ovata (LD50 = 233 mg/ ml), and 100% for D. amazonica (LD50 = 212 mg/ ml) whereas in the control groups maximum mortality never surpassed 13%. Preliminary assays indicated that A. ovata and D. amazonica displayed significant insecticide effect against L. longipalpis.

Biological variability in clinical isolates of Trichomonas vaginalis

Eighteen clinical isolates of Trichomonas vaginalis were obtained from women who attended health centers of the Goverment of Madrid. A total of 1,848 vaginal specimens recovered during the gynaecological examination were seeded in culture tubes containing liquid Diamond medium. Pathogenicity to mice was determined after intraperitoneal inoculation of mice by quantification of mortality and gross damage to abdominal organs. As could be expected, a broad variability was obtained, being some of the isolates more virulent than the reference strain. Regarding to metronidazole susceptibility, none resistant isolate was found but different degrees of susceptibility were determined.

A study of the cambial zone and conductive phloem of common beech (Fagus sylvatica L.) using an image analysis method. I. Influence of tree age on the structure

Quantification is a major problem when using histology to study the influence of ecological factors on tree structure. This paper presents a method to prepare and to analyse transverse sections of cambial zone and of conductive phloem in bark samples. The following paper (II) presents the automated measurement procedure. Part I here describes and discusses the preparation method, and the influence of tree age on the observed structure. Highly contrasted images of samples extracted at breast height during dormancy were analysed with an automatic image analyser. Between three young (38 years) and three old (147 years) trees, age-related differences were identified by size and shape parameters, at both cell and tissue levels. In the cambial zone, older trees had larger and more rectangular fusiform initials. In the phloem, sieve tubes were also larger, but their shape did not change and the area for sap conduction was similar in both categories. Nevertheless, alterations were limited, and demanded statistical analysis to be identified and ascertained. The physiological implications of the structural changes are discussed.

Ecology of Haemagogus sp. and Sabethes sp. (Diptera: Culicidae) in relation to the microclimates of the Caxiuanã National Forest, Pará, Brazil

This study was conducted in a meteorological tower located in the Caxiuanã Forest (municipality of Melgaço, Pará, Brazil) with the aim of assessing the vertical stratification of species of Haemagogus and Sabethes, potential vectors of the yellow fever virus. To investigate the role of microclimates in mosquito stratification, bimonthly collections were conducted at ground level (0 m), 8 m, 16 m and 30 m (canopy level), with the aid of entomological nets and suction tubes, from July 2005-April 2006. A total of 25,498 mosquitoes were collected; specimens of Sabethes sp. and Haemagogus janthinomyswere found mostly at heights of 16 m and 30 m while Hg. leucocelaenus was most frequently observed at ground level. The largest number of vector species was collected during the rainiest months, but this difference between seasons was not statistically significant. However, the number of Hg. janthinomys was positively correlated with variations in temperature and relative humidity.

The vacuolar transporter chaperone (VTC) complex is required for microautophagy.

Microautophagy involves direct invagination and fission of the vacuolar/lysosomal membrane under nutrient limitation. This occurs by an autophagic tube, a specialized vacuolar membrane invagination that pinches off vesicles into the vacuolar lumen. In this study we have identified the VTC (vacuolar transporter chaperone) complex as required for microautophagy. The VTC complex is present on the ER and vacuoles and at the cell periphery. On induction of autophagy by nutrient limitation the VTC complex is recruited to and concentrated on vacuoles. The VTC complex is inhomogeneously distributed within the vacuolar membranes, showing an enrichment on autophagic tubes. Deletion of the VTC complex blocks microautophagic uptake into vacuoles. The mutants still form autophagic tubes but the production of microautophagic vesicles from their tips is impaired. In line with this, affinity-purified antibodies to the Vtc proteins inhibit microautophagic uptake in a reconstituted system in vitro. Our data suggest that the VTC complex is an important constituent of autophagic tubes and that it is required for scission of microautophagic vesicles from these tubes.

Growth, cysts and kinetics of Borrelia garinii (Spirochaetales: Spirochaetacea) in different culture media

The aim of the present paper was to evaluate cyst formation and growth parameters of Borrelia garinii in a range of media differing in formulation and cost. A qualitative assessment of morphology and motility of B. garinii was conducted. All media were prepared aseptically and used in test tubes or Petri dishes. For each medium, the initial spirochete concentration was standardized to 10³ spirochets/mL. The following culture media were suitable to grow B. garinii: Barbour-Stoenner-Kelly, brain heart infusion and PMR. Growth was minimal at six weeks post-inoculation and maximum spirochete density was observed between 9-12 weeks. Often, the cultures developed cysts of different sizes, isolated or in groups, with a spiraled portion of variable sizes, mainly in unfavorable culture media. Brazilian Lyme disease-like illness, also known as Baggio-Yoshinari syndrome (BYS), is a new and interesting emerging tick-borne disease, caused by Borrelia burgdorferi sensu lato spirochetes, only during its cystic forms. It has been assumed that the peculiar clinical and laboratory features of BYS are consequential to the absence of a human sucker Ixodes ricinus complex tick at risk areas in Brazil, supporting the concept that the borrelia phenotypic expression pattern is modified as it is transmitted through the host.