scholarly journals Effects of multiple doses of simvastatin and artesunate monotherapy on SCHISTOSOMA MANSONI adult worms during infection in hyperlidemic mice

2021 ◽  
Vol 50 (1) ◽  
pp. 21-39
Author(s):  
Alba Cristina Miranda de Barros Alencar ◽  
Thais Silva dos Santos ◽  
Luciana Brandao-Bezerra ◽  
Eduardo Jose Lopes-Torres ◽  
Jose Firmino Nogueira Neto ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Schistosoma Mansoni ◽  
Reproductive System ◽  
Severe Damage ◽  
High Fat ◽  
Multiple Doses ◽  
Antischistosomal Activity ◽  
Males And Females ◽  
High Fat Chow ◽  
Scanning Electron

A single dose of simvastatin and of artesunate monotherapy cause damage to the reproductive system of schistosomes as well as severe tegumental damage in male worms recovered from mice fed high-fat chow. This study aims to investigate whether treatment with multipledose regimes may offer more antischistosomal activity advantages than single daily dosing in mice fed high-fat chow. For this purpose, nine weeks post-infection, Swiss Webster mice were gavaged with simvastatin (200 mg/kg) or artesunate (300 mg/kg) for five consecutive days and euthanized two weeks post-treatment. Adult worms were analyzed using brightfieldmicroscopy, confocal microscopy and scanning electron microscopy, presenting damages caused by simvastatin and artesunate to the reproductive system of males and females as well as tegument alterations, including peeling, sloughing areas, loss of tubercles, tegumental bubbles and tegument rupture exposing subtegumental tissue. The overall findings in this study revealed the potential antischistosomal activity of simvastatin and artesunate against Schistosoma mansoni adult worms, in addition to showing that multiple doses of either monotherapy caused severe damage to the tegument.KEY WORDS: Schistosoma mansoni; hyperlipidemia; simvastatin; artesunate; microscopy.

Failure Analysis of a Shaft Belonging to a Ship Engine Speed Controller

1999 ◽  
Author(s):  
Miguel V. Figueiredo ◽  
Fernando M. Oliveira ◽  
Paulo T. de Castro ◽  
António A. Fernandes
Keyword(s):  
Electron Microscopy ◽  
Fracture Surface ◽  
Failure Analysis ◽  
Laboratory Tests ◽  
Engine Speed ◽  
Notch Toughness ◽  
Severe Damage ◽  
Speed Controller ◽  
Service Conditions ◽  
Scanning Electron

Abstract The fracture of a shaft belonging to the speed controller of a ship’s engine is presented. An over-speed situation occurred as a result of the fracture of this shaft, which led to severe damage to the engine. The failure examination concentrated first on the study of the available evidence, which included the analysis of the shaft’s material and fracture surface. The shaft’s material was studied as concerns chemical composition, mechanical properties and micrographic structure. The fracture surface was studied using scanning electron microscopy. Several different destructive laboratory tests were conducted on the material, in order to obtain fracture surfaces which could be used for comparison purposes, and thus help to identify the cause of the fracture. The next step of the failure analysis consisted of a stress analysis of the shaft under service conditions. A probable scenario for the failure was proposed, which helped the interested parties to reach an agreement concerning responsibilities for the failure. It was found that the shaft material presented low notch toughness. The stress levels at the time of the accident imply that it is unlikely that the fracture was due to fatigue. The probable cause of the failure was sudden blockage of the shaft.

Antennal Sensilla of Chrysis shanghalensis (Hymenoptera: Chrysididae), a Larval Ectoparasite of Monema flavescens (Lepidoptera: Limacodidae)

2021 ◽  
Vol 56 (1) ◽  
pp. 1-11
Author(s):  
Shu Z. Yang ◽  
Mei H. Yang ◽  
Yun Xu ◽  
Jin T. Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Natural Enemy ◽  
Tree Species ◽  
External Morphology ◽  
Antennal Sensilla ◽  
Sensilla Basiconica ◽  
Sensilla Trichodea ◽  
Males And Females ◽  
Scanning Electron

Abstract Chrysis shanghalensis Smith (Hymenoptera: Chrysididae) is an ectoparasitoid and important natural enemy of Monema flavescens Walker (Lepidoptera: Limacodidae), a serious defoliator of a number of tree species. The external morphology of the antennal sensilla of this parasitoid was examined by scanning electron microscopy, and types and distribution of sensilla were recorded. The antennae of C. shanghalensis were geniculate in shape and composed of a scape with radicula, a pedicel, and a flagellum divided into 11 flagellomeres in males and females. Cuticular pore and 14 types of sensilla were identified on the antennae of both sexes. These included aporous Böhm's bristles, sensilla trichodea 1, 2, and 3 (nonporous), sensilla trichodea 4 (multiporous), two types of sensilla chaetica (nonporous), four morphological types of sensilla basiconica (multiporous), two morphological types of sensilla coeloconica (multiporous), and one type of sensillum campaniforme (nonporous).

Microstructure of Female Reproductive System of Phenacoccus fraxinus Tang (Hemiptera: Coccoidea: Pseudococcidae)

2008 ◽  
Vol 43 (4) ◽  
pp. 362-372 ◽  
Author(s):  
Xiaohong Fu ◽  
Yingping Xie ◽  
Xiaomin Zhang ◽  
Weimin Liu
Keyword(s):  
Electron Microscopy ◽  
Reproductive System ◽  
Lipid Droplets ◽  
Nurse Cells ◽  
Serial Sections ◽  
Female Reproductive System ◽  
Follicular Cells ◽  
Yolk Lipid ◽  
Egg Chamber ◽  
Scanning Electron

The structure of the female reproductive system of the mealybug, Phenacoccus fraxinus Tang (Hemiptera: Coccoidea: Pseudococcidae), was studied using standard histological examination of serial sections of tissues embedded in paraffin and by scanning electron microscopy. Our studies revealed that the ovary of P. fraxinus has paired lateral oviducts comprised of numerous short ovarioles. Each ovariole consists of 1 trophic chamber, 1 egg chamber and 1 pedicel which connect to the bottom of the egg chamber. Three nurse cells were observed in the trophic chamber, whereas yolk, lipid droplets and an oocyte were seen in the egg chamber. Follicular cells were arranged along the wall of the egg chamber and extended to form the pedicel. Many tracheae and tracheoles of various thicknesses were observed innervating the clusters of ovaries.

scholarly journals Sexual dichroism and pigment localization in the wing scales of Pieris rapae butterflies

2006 ◽  
Vol 274 (1606) ◽  
pp. 97-102 ◽  
Author(s):  
M.A Giraldo ◽  
D.G Stavenga
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Pieris Rapae ◽  
Reflectance Spectra ◽  
High Concentration ◽  
Pieris Rapae Crucivora ◽  
Males And Females ◽  
Wing Coloration ◽  
Scanning Electron ◽  
Wing Scales

The beads in the wing scales of pierid butterflies play a crucially important role in wing coloration as shown by spectrophotometry and scanning electron microscopy (SEM). The beads contain pterin pigments, which in Pieris rapae absorb predominantly in the ultraviolet (UV). SEM demonstrates that in the European subspecies Pieris rapae rapae , both males and females have dorsal wing scales with a high concentration of beads. In the Japanese subspecies Pieris rapae crucivora , however, only the males have dorsal wing scales studded with beads, and the dorsal scales of females lack beads. Microspectrophotometry of single scales without beads yields reflectance spectra that increase slightly and monotonically with wavelength. With beads, the reflectance is strongly reduced in the UV and enhanced at the longer wavelengths. By stacking several layers of beaded scales, pierid butterflies achieve strong colour contrasts, which are not realized in the dorsal wings of female P. r. crucivora . Consequently, P. r. crucivora exhibits a strong sexual dichroism that is absent in P. r. rapae .

Adult worm tegumental damage and egg-granulomas in praziquantel-resistant and -susceptible Schistosoma mansoni treated in vivo

2002 ◽  
Vol 76 (4) ◽  
pp. 327-333 ◽  
Author(s):  
Y.-S. Liang ◽  
G.C. Coles ◽  
J.-R. Dai ◽  
Y.-C. Zhu ◽  
M.J. Doenhoff
Keyword(s):  
Schistosoma Mansoni ◽  
Drug Resistant ◽  
Severe Damage ◽  
Drug Pressure ◽  
Electron Microscopic ◽  
Scanning Electron Microscopic ◽  
Susceptible Control ◽  
Effect Of Treatment ◽  
Scanning Electron

AbstractThe effect of treatment with praziquantel (PZQ) on the tegument of adult Schistosoma mansoni worms and on liver egg-granulomas has been examined in mice infected with PZQ-resistant and -susceptible parasite isolates. Two PZQ-resistant S. mansoni isolates, one selected by passage in the laboratory under drug pressure and one from Senegal established from eggs excreted by an uncured patient, were compared with PZQ-susceptible control isolates. Scanning electron microscopic observations on the tegument of Schistosoma adult worms treated in vivo with PZQ showed that more severe damage was inflicted by PZQ on susceptible worms than on drug-resistant worms. Observations on the pathology of Schistosoma egg-granulomas in the liver of infected mice after treatment with PZQ indicated that eggs from susceptible control isolates were more sensitive to PZQ than those from drug-resistant isolates.

scholarly journals A single oral fixed - dose praziquantel-miltefosine nanocombination for effective control of experimental Schistosomiasis mansoni

2020 ◽  
Author(s):  
Maha Mohamed Eissa ◽  
Mervat El-Azzouni ◽  
Labiba Khalil El-Khordagui ◽  
Amany Abdel Bary ◽  
Riham Mohamed El-Moslemany ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Combination Therapy ◽  
Schistosoma Mansoni ◽  
Drug Repurposing ◽  
Fixed Dose ◽  
Schistosomiasis Control ◽  
Lipid Nanocapsules ◽  
Therapeutic Profile ◽  
Scanning Electron

Abstract Background: Schistosomiasis control has been centered to date on praziquantel, with shortcomings involving ineffectiveness against immature worms, reinfection and emergence of drug resistance. Strategies based on drug repurposing and/or praziquantel combination therapy proved effective, though with some limitations. Combining such strategies with nanotechnology would further augment therapeutic benefits. Nanocarrier-mediated delivery of multiple drugs in schistosomiasis control has not been documented to date. Our objective was to combine drug repurposing, combinational therapy and nanotechnology for the development of a single oral fixed dose nanocombination to improve praziquantel therapeutic profile. This was based on praziquantel and an antischistosomal repurposing candidate miltefosine, co-loaded into lipid nanocapsules in reduced doses. Methods: Two fixed dose lipid nanocapsule formulations were prepared at two concentration levels of praziquantel and miltefosine. Their antischistosomal activity in comparison with control singly loaded lipoid nanocapsules was assessed in Schistosoma mansoni- infected mice. Single oral dos of 250mg praziquantel-20mg miltefosine/kg and 125mg praziquantel-10mg miltefosine/kg were administered on the initial day of infection, 21st and 42nd days post infection. Scanning electron microscopy, parasitological and histopathological studies were used for assessment. In vivo data were subjected to analysis of variance and post hoc test (Tukey) was used for pairwise comparisons. Results: Lipid nanocapsules showed a mean diameter of 58 nm and high entrapment efficiency of both drugs (>95%). Compared to singly loaded lipid nanocapsules, the larger dose praziquantel-miltefosine nanocombination exerted high antischistosomal efficacy in terms of % reduction of worm burden, particularly when given against invasive and juvenile worms, and amelioration of hepatic granulomas. Scanning electron microscopy revealed extensive tegumental damage with noticeable deposition of nanostructures. Conclusions: A fixed dose praziquantel-miltefosine nanocombination offers great potential as a novel single dose oral antischistosomal therapy offering multistage activity and protection against hepatic pathology. The novel drug repurposing/combination therapy/nanotechnology multiple approach has the potentials of improving the therapeutic profile of praziquantel, achieving radical cure, hindering resistance to the component drugs, and simplifying praziquantel chemotherapy. Key words: Praziquantel, miltefosine, lipid nanocapsules, Schistosoma mansoni, nanocombination, multistage activity, tegumental targeting, scanning electron microscopy. ​ [LE1] [LE1]

First report of Schulzia travassosi (Nematoda, Trichostrongylina, Molineoidea) for amphibians of the Chaco region in Argentina and proposal of Oswaldocruzia melanostictusi nov. comb.

2015 ◽  
Vol 60 (4) ◽  
Author(s):  
Cynthya E. González ◽  
Monika I. Hamann
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
First Record ◽  
Nematode Parasite ◽  
First Report ◽  
Chaco Region ◽  
Males And Females ◽  
Almost All ◽  
Chaco Province ◽  
Scanning Electron

AbstractThis is the first record of the nematode parasite Schulzia travassosi (Trichostrongylina, Molineidae) in two Argentinean amphibians, Leptodactylus bufonius and Rhinella major, collected in two localities of the Chaco region, Las Lomitas (Formosa Province) and Taco Pozo (Chaco Province). The species was observed using light and scanning electron microscopy (SEM) and compared with previous studies of Paraguayan specimens. Regarding metric characters, the measurements found in Argentinean specimens generally did not differ from those of Paraguayan specimens; some differences were observed in the total length of males and females (some longer and some shorter than Paraguayan specimens), length of the oesophagus (in almost all specimens shorter than in Paraguayan ones) and position of the vulva (nearer to posterior end in Argentinean specimens). The branches and sphincter of ovejector are slightly longer than in Paraguayan female specimens. In males, ray 4 is almost the same length as rays 2, 3 and 5, 6. Cephalic end, cephalic vesicle, synlophe and vulvar depression were viewed under SEM. Schulzia melanostictusi Chopra, Shing and Kumar, 1986 is reassigned as Oswaldocruzia melanostictusi (Chopra, Shing and Kumar, 1986) nov. comb.

Sign in / Sign up

Export Citation Format

Share Document