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For decades antimonials were the drugs of choice for the treatment of visceral leishmaniasis (VL), but the recent emergence of resistance has made them redundant as first-line therapy in the endemic VL region in the Indian subcontinent. The application of other drugs has been limited due to adverse effects, perceived high cost, need for parenteral administration and increasing rate of treatment failures. Liposomal amphotericin B (AmB) and miltefosine (MIL) have been positioned as the effective first-line treatments; however, the number of monotherapy MIL-failures has increased after a decade of use. Since no validated molecular resistance markers are yet available, monitoring and surveillance of changes in drug sensitivity and resistance still depends on standard phenotypic in vitro promastigote or amastigote susceptibility assays. Clinical isolates displaying defined MIL- or AmB-resistance are still fairly scarce and fundamental and applied research on resistance mechanisms and dynamics remains largely dependent on laboratory-generated drug resistant strains. This review addresses the various challenges associated with drug susceptibility and -resistance monitoring in VL, with particular emphasis on the choice of strains, susceptibility model selection and standardization of procedures with specific read-out parameters and well-defined threshold criteria. The latter are essential to support surveillance systems and safeguard the limited number of currently available antileishmanial drugs.
To highlight the value of sialendoscopy during transoral resection of the sublingual gland for a plunging ranula to prevent iatrogenic injury to the submandibular duct.
Method and results:
The clinical course of a 20-year-old male with a plunging ranula was analysed. The patient underwent transoral resection of the affected sublingual gland and pseudocyst. Sialendoscopy was used to confirm patency of the submandibular duct with placement of a Marchal dilator to aid in preservation of the duct during sublingual gland dissection. The sublingual gland was successfully removed, with no injury to the submandibular duct or lingual nerve. During follow up, the patient had slight numbness to the tip of the tongue, which resolved after 2–3 days. Post-operative examination showed the submandibular duct to be intact and there was no swelling of the submandibular area.
Sialendoscopy-assisted transoral sublingual gland resection for a plunging ranula is a safe and effective technique. Sialendoscopy aids in skeletonisation and preservation of the submandibular duct.
Inclusion of fermentable fibres in the diet can have an impact on the hindgut microbiome and provide numerous health benefits to the host. Potato fibre (PF), a co-product of potato starch isolation, has a favourable chemical composition of pectins, resistant and digestible starch, cellulose, and hemicelluloses. The objective of the present study was to evaluate the effect of increasing dietary PF concentrations on the faecal microbiome of healthy adult dogs. Fresh faecal samples were collected from ten female dogs with hound bloodlines (6·13 (sem 0·17) years; 22·0 (sem 2·1) kg) fed five test diets containing graded concentrations of PF (0, 1·5, 3, 4·5 or 6 % as-fed; Roquette Frères) in a replicated 5 × 5 Latin square design. Extraction of DNA was followed by amplification of the V4–V6 variable region of the 16S rRNA gene using barcoded primers. Sequences were classified into taxonomic levels using Basic Local Alignment Search Tool (BLASTn) against a curated GreenGenes database. Inclusion of PF increased (P< 0·05) the faecal proportions of Firmicutes, while those of Fusobacteria decreased (P< 0·05). Similar shifts were observed at the genus level and were confirmed by quantitative PCR (qPCR) analysis. With increasing concentrations of PF, faecal proportions of Faecalibacterium increased (P< 0·05). Post hoc Pearson's correlation analysis showed positive (P< 0·05) correlations with Bifidobacterium spp. and butyrate production and Lactobacillus spp. concentrations. Overall, increases in the proportion of Faecalibacterium (not Lactobacillus/Bifidobacterium, as confirmed by qPCR analysis) and faecal SCFA concentrations with increasing dietary PF concentrations suggest that PF is a possible prebiotic fibre.
In vitro preservation of the male gamete is a challenge in the development of artificial insemination techniques for domestic animals. Specific strategies and diluents have been developed for the preservation of the fertilizing ability of the semen for each species. However, the epididymal medium has been demonstrated to be the best sperm environment to maintain sperm viability over several days and weeks for mammals. The aims of this study were to evaluate the motility and in vivo fertility of ram epididymal spermatozoa when the semen was stored for up to 4 days at 4°C undiluted in epididymal plasma. The study was undertaken with two ovine breeds (Ile de France and Corriedale). The motility of epididymal spermatozoa was better preserved in the undiluted epididymal fluid than when epididymal spermatozoa were diluted in classic ovine extender such as skim milk. During storage, the decrease in the percentage of motile sperm was lower if the epididymal spermatozoa were collected immediately after epididymal sampling than 24 h after castration or animal death. The fertility obtained after cryopreservation of the stored sperm and subsequent intrauterine insemination ranged from 55% to 24% following 24 to 96-h sperm storage. There was a linear regression relationship between fertility and the number of motile sperm inseminated for both breeds. These results show that it is possible to keep epididymal sperm motile and fertile for several days without dilution. Such a method of sperm preservation could be a final possibility for animals of high genetic value or for endangered species when the collection of semen before death of the animal is not possible.
Triatoma virus (TrV) is a small, non-enveloped virus that has a+ssRNA genome and is currently classified under the Cripavirus genus of the Dicistroviridae family. TrV infects haematophagous triatomine insects (Hemiptera: Reduviidae), which are vectors of American trypanosomosis (Chagas disease). TrV can be transmitted through the horizontal faecal–oral route, and causes either deleterious sublethal effects or even the death of laboratory insect colonies. Various species of triatomines from different regions of Latin America are currently being reared in research laboratories, with little or no awareness of the presence of TrV; therefore, any biological conclusion drawn from experiments on insects infected with this virus is inherently affected by the side effects of its infection. In this study, we developed a mathematical model to estimate the sample size required for detecting a TrV infection. We applied this model to screen the infection in the faeces of triatomines belonging to insectaries from 13 Latin American countries, carrying out the identification of TrV by using RT-PCR. TrV was detected in samples coming from Argentina, which is where the virus was first isolated from Triatoma infestans (Hemiptera: Reduviidae) several years ago. Interestingly, several colonies from Brazil were also found infected with the virus. This positive result widens the TrV's host range to a total of 14 triatomine species. Our findings suggest that many triatomine species distributed over a large region of South America may be naturally infected with TrV.
One of the most routine uses of fluorescence microscopy is colocalization, i.e., the demonstration of a relationship between pairs of biological molecules. Frequently this is presented simplistically by the use of overlays of red and green images, with areas of yellow indicating colocalization of the molecules. Colocalization data are rarely quantified and can be misleading. Our results from both synthetic and biological datasets demonstrate that the generation of Pearson's correlation coefficient between pairs of images can overestimate positive correlation and fail to demonstrate negative correlation. We have demonstrated that the calculation of a thresholded Pearson's correlation coefficient using only intensity values over a determined threshold in both channels produces numerical values that more accurately describe both synthetic datasets and biological examples. Its use will bring clarity and accuracy to colocalization studies using fluorescent microscopy.
An electric network is constituted by generators providing power to various
loads. The induction machine is the most common motor in the industrial
applications because of its simplicity of construction, its reliability and
its low cost. It allows the constant speed applications when it is directly
supplied by the network and variable speed ones with the use of power
converters. These speed drives induce important harmonic perturbations in
the power system and in the motor side. In this context, we are interested
by the frequential modelling of the induction machine in order to simulate
the line current with its harmonic components. In order to use the induction
machine models, it is necessary to identify their parameters and therefore
realizing specific and sufficiently informative tests. Several tests of
identification are presented in the literature; their differences and their
relevance have not been discussed. This study deals with the realization and
the comparison of several types of frequential tests (constant voltage,
constant V/f, injection of DC current) for induction machine models
identification. The comparison of the simulation results with the
experimental measurements allows electing the most representative of the
induction machine behaviour.
L'influence de Tubificidae du genre Tubifex sur le relargage des différentes formes du phosphore (particulaire, organique dissous et orthophosphates) a été étudiée au laboratoire, en conditions contrôlées. Lorsque le milieu est oxygéné, les vers entraînent une augmentation du phosphore particulaire dans la colonne d'eau mais aux dépens des orthophosphates, de sorte que le relargage de phosphore total n'est guère supérieur à celui du témoin. En milieu appauvri en oxygène, la différence est plus nette mais elle est surtout due au phosphore particulaire plus abondant. Ce phosphore particulaire semble provenir d'une agitation plus importante car la défécation est réduite par le déficit en oxygène. Le transfert apparent orthophosphates-phosphore particulaire pose le problème de la biodisponibilité de ce dernier qui conditionne l'action positive ou négative des Tubifex sur la nutrition algale.
Calculations of crystal size distributions in oriented clays (montmorillonite and kaolinite) are carried out utilizing X-ray diffraction data together with a method based on information theory. Two different procedures for dealing with the available data are compared. One of them involves some points of the corresponding spectrum, the other correlates the data by means of their moments.
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