The human cases of eosinophilic meningitis recently reported from Brazil have focused the attention of the public health agencies on the role the introduced snail
Achatina fulica plays as hosts of ...the metastrongylid nematodes. Determining the potential of this snail to host and develop infective larval stages of metastrongylids in the wild and identify the species harbored by them is crucial for designing effective control measures. Here we assess if
A. fulica may act as intermediate host of
A. cantonensis at the peridomiciliary areas of a patient's house from state of Pernambuco (PE), who was diagnosed with eosinophilic meningitis and a history of ingesting raw molluscs. Larvae obtained from naturally infected
A.
fulica were orally administered to
Rattus norvegicus. The worms were collected from the pulmonary artery and brain, and were morphologically characterized and compared to the Japan isolate of
A. cantonensis. Adult worms and infective L
3 larvae (PE isolate) recovered from
A. fulica specimens were also analyzed by polymerase chain reaction and restriction fragment length polymorphism of ITS2 region from rDNA and compared to
A. cantonensis (ES isolate),
A. vasorum (MG isolate) and
A.
costaricensis (RS isolate). The large size of the spicules (greater than those observed in other species of
Angiostrongylus) and the pattern of the bursal rays agree with the original species description by
Chen (1935). Furthermore, the morphology of the PE isolate was similar to that of Japan isolate. The PCR-RFLP profiles obtained were distinctive among species and no variation in patterns was detected among adult individuals from
A. cantonensis isolates from PE and ES. The importance of
A. fulica as an intermediate host of eosinophilic menigoencepahlitis in Brazil is emphasized.
ABSTRACT
STUDY QUESTION
Is permeable cryoprotectant-free vitrification of native sperm samples a good alternative to conventional slow freezing?
SUMMARY ANSWER
The permeable cryoprotectant-free sperm ...vitrification protocol tested in this study renders considerably better recovery rates of good quality sperm compared to slow freezing.
WHAT IS KNOWN ALREADY
Slow freezing is currently the most commonly used technique for sperm cryopreservation, though this method has been repeatedly shown to have negative effects on both structural and functional sperm features. New alternative methods such as vitrification have been established as a successful alternative in other reproductive cell types, but vitrification of spermatozoa is still a rather unexplored methodology, with limited studies showing its efficacy in male gametes.
STUDY DESIGN SIZE, DURATION
This study included 18 normozoospermic sperm samples from patients seeking ART treatment between 2014 and 2015. The effects of a new vitrification protocol on functional and structural sperm quality parameters in comparison to fresh and slow-frozen samples were assessed.
PARTICIPANTS/MATERIALS, SETTING, METHODS
All samples were divided into three aliquots: fresh (F), slow freezing–thawing (S) and vitrification-warming (V). Sperm concentration, motility, morphology, vitality, DNA fragmentation, cytoskeleton integrity and spontaneous acrosome reaction were assessed and compared between the groups.
MAIN RESULTS AND THE ROLE OF CHANCE
Results showed improved preservation of sperm features after vitrification compared to conventional freezing. Permeable cryoprotectant-free vitrification presented a significantly higher percentage of live spermatozoa, than slow freezing, better preservation of acrosomes was achieved in vitrified samples and DNA fragmentation was reduced approximately one-third on average compared to slow freezing. Regarding tubulin assay, three different labelling patterns were observed. The frequency of these labelling patterns was similar in F and V groups but this was not the case of the S group. The multivariate analysis of all sperm quality parameters studied revealed that the V group presented features that are closer to the F group than the S group, indicating that samples are better preserved through vitrification than slow freezing.
LIMITATIONS REASONS FOR CAUTION
This validation has been undertaken only on normozoospermic sperm samples. It would be necessary to compare these results in pathological samples and also to evaluate the influence of the application of this methodology on clinical outcomes.
WIDER IMPLICATIONS OF THE FINDINGS
The sperm vitrification protocol here described warrants better maintenance of sperm quality parameters than traditional freezing methods and may be a good alternative to preserve sperm samples from patients seeking IVF treatment.
STUDY FUNDING/COMPETING INTEREST(S)
This study was funded by IVF-Spain Foundation. The authors have no conflicts of interest to declare.
Abstract One hundred thirty-six isolates, 88 human and 48 environmental, that met the requirements to belong to the genus Paenibacillus were identified using a polyphasic taxonomic approach known as ...16S rRNA plus phenotypic traits. Thirty-seven Paenibacillus species were identified; some had not been previously reported from clinical samples. The main species were P. pabuli (13 isolates), P. provencensis (11), P. phoenicis (9) and P. lautus (8). P. pabuli (11/13) and P. provencensis (8/11) were mainly environmental isolates, while P. phoenicis (9/9) and P. lautus (6/8) were mainly human isolates. Despite the difficulties in assigning to human Paenibacillus isolates a role as a pathogen or contaminant, here 25% of the isolates were involved in true infections, especially in those cases that affected abscesses, wound exudates, ocular infections and diverse fluids. In addition, 15 isolates were identified as 11 ‘Candidatus’ to a new species, all of them from human specimens except one that was obtained from laboratory air. The antimicrobial susceptibility testing showed 95.6% of isolates were resistant to ampicillin, 44% were resistant to cotrimoxazole, 20 to 30% were resistant to cefotaxime and vancomycin and 13% were resistant to rifampicin and erythromycin.
Increasing evidence indicates that circulating insulin-like growth factor I (IGF-I) acts as a peripheral neuroactive signal participating not only in protection against injury but also in normal ...brain function. Epidemiological studies in humans as well as recent evidence in experimental animals suggest that blood-borne IGF-I may be involved in cognitive performance. In agreement with observations in humans, we found that mice with low-serum IGF-I levels due to liver-specific targeted disruption of the IGF-I gene presented cognitive deficits, as evidenced by impaired performance in a hippocampal-dependent spatial-recognition task. Mice with serum IGF-I deficiency also have disrupted long-term potentiation (LTP) in the hippocampus, but not in cortex. Impaired hippocampal LTP was associated with a reduction in the density of glutamatergic boutons that led to an imbalance in the glutamatergic/GABAergic synapse ratio in this brain area. Behavioral and synaptic deficits were ameliorated in serum IGF-I-deficient mice by prolonged systemic administration of IGF-I that normalized the density of glutamatergic boutons in the hippocampus. Altogether these results indicate that liver-derived circulating IGF-I affects crucial aspects of mature brain function; that is, learning and synaptic plasticity, through its trophic effects on central glutamatergic synapses. Declining levels of serum IGF-I during aging may therefore contribute to age-associated cognitive loss.
Whether insulin-like growth factor I (IGF-I) signaling in Alzheimer's disease (AD) is beneficial or detrimental remains controversial. We now show that a competitive regulation by IGF-I of the ...phosphatase calcineurin in reactive, but not in quiescent astrocytes drives Alzheimer's pathology. Calcineurin de-phosphorylates the transcription factor Foxo3 in response to tumor necrosis factor-α (TNFα), an inflammatory cytokine increased in AD, activating nuclear factor-κB (NFκB) inflammatory signaling in astrocytes. In turn, IGF-I inactivates and displaces Foxo3 from calcineurin in TNFα-stimulated astrocytes by recruiting the transcription factor peroxisome proliferator-activated receptor-γ, and NFκB signaling is inhibited. This antagonistic mechanism reversibly drives the course of the disease in AD mice, even at advanced stages. As hallmarks of this calcineurin/Foxo3/NFκB pathway are present in human AD brains, treatment with IGF-I may be beneficial by antagonizing it.
The role of insulin-like growth factor I (IGF-I) and its receptor (IGF-IR) in brain pathology is still unclear. Thus, either reduction of IGF-IR or treatment with IGF-I, two apparently opposite ...actions, has proven beneficial in brain diseases such as Alzheimer´s dementia (AD). A possible explanation of this discrepancy is that IGF-I down-regulates brain IGF-IR levels, as previously seen in a mouse AD model. We now explored whether under normal conditions IGF-I modulates its receptor. We first observed that in vitro, IGF-I reduced IGF-IR mRNA levels in all types of brain cells including neurons, astrocytes, microglia, endothelial cells, and oligodendrocytes. IGF-I also inhibited its own expression in neurons and brain endothelium. Next, we analyzed in vivo actions of IGF-I. As serum IGF-I can enter the brain, we injected mice with IGF-I intraperitoneously. As soon as one hour after injection, decreased hippocampal IGF-I levels were observed, followed by increased IGF-I and IGF-IR mRNAs six hours later. As environmental enrichment (EE) stimulates the entrance of serum IGF-I into the brain, we analyzed whether a physiological entrance of IGF-I also produced changes in brain IGF-IR. Stimulation of IGF-IR by EE triggered a gradual decrease in hippocampal IGF-I levels. After six hours of EE exposure, IGF-I levels reached a significant decrease in parallel with increased IGF-IR expression. After longer times, IGF-IR mRNA levels returned to baseline. Thus, under non-pathological conditions, IGF-I regulates brain IGF-IR. Because baseline IGF-IR levels are rapidly restored, a tight control of brain IGF-IR expression seems to operate under physiological conditions.
Abstract
Anecdotal evidence suggests that community infection control measures during the COVID-19 outbreak have modified the number and natural history of acute surgical inflammatory processes ...(ASIP—appendicitis, cholecystitis, diverticulitis and perianal abscesses) admissions. This study aims to evaluate the impact of the COVID-19 pandemic on the presentation and treatment ASIP and quantify the effect of COVID-19 infection on the outcomes of ASIP patients. This was a multicentre, comparative study, whereby ASIP cases from 2019, 2020 and 2021 (March 14th to May 2nd) were analyzed. Data regarding patient and disease characteristics as well as outcomes, were collected from sixteen centres in Madrid, and one in Seville (Spain). The number of patients treated for ASIP in 2019 was 822 compared to 521 in 2020 and 835 in 2021. This 1/3rd reduction occurs mainly in patients with mild cases, while the number of severe cases was similar. Surgical standards suffered a step back during the first wave: Lower laparoscopic approach and longer length of stay. We also found a more conservative approach to the patients this year, non-justified by clinical circumstances. Luckily these standards improved again in 2021. The positive COVID-19 status itself did not have a direct impact on mortality. Strikingly, none of the 33 surgically treated COVID positive patients during both years died postoperatively. This is an interesting finding which, if confirmed through future research with a larger sample size of COVID-19 positive patients, can expedite the recovery phase of acute surgical services.
This paper investigates the tensile behavior of green ultra-high-performance fiber-reinforced concrete (UHPFRC) using commercially available steelfibers. An ecofriendly ultra-high-performance ...concrete (UHPC) with a low carbon footprint was developed, aiming for a compressive strength of 150 MMPa (22 ksi) and a high packing density (0.81) while using recycled glass powder and micro-limestone powder as partial substitution of silica fume and ordinary portland cement. Besides the commercially available normal-strength deformed steel fibers, high-strength smooth steel fibers were used to establish a comparison. The study showed that, with appropriate hooked normal-strength and smooth high-strength steel fibers, 1% of fiber is enough to achieve strain hardening behavior. Moreover, the smooth fibers achieved the maximum tensile strength (sigma.sub.pc = 11.04 MPa) when 2% of volume was used. However, despite having less tensile strength, only the hooked-end fibers achieved a maximum post-cracking strain (epsilon.sub.pc) of over 0.3% using 2% of volume. Keywords: commercially available fibers; composite; direct tensile behavior; supplementary cementitious materials (SCM); ultra-high-performance fiber-reinforced concrete (UHPFRC).
Aims. We study the origin of large abundances of complex organic molecules in the Galactic center (GC). Methods. We carried out a systematic study of the complex organic molecules CH sub(3) OH, C ...sub(2) H sub(5) OH, (CH sub(3)) sub(2) O, HCOOCH sub(3), HCOOH, CH sub(3) COOH, H sub(2) CO, and CS toward 40 GC molecular clouds. Using the LTE approximation, we derived the physical properties of GC molecular clouds and the abundances of the complex molecules. The abundances of complex organic molecules in the GC are compared with those measured in hot cores and hot corinos, in which these complex molecules are also abundant. Results. The CH sub(3) OH abundance between clouds varies by nearly two orders of magnitude from beta Pictoris. In particular, the scattered light surface brightness profile falls off as beta Pictoris and 35 AU for AU Mic. In both cases, the disk color rises as the distance increases beyond these reference radii. Aims. In this paper, we present the first comprehensive analysis of the AU Mic disk properties since the system was resolved by Kalas et al. (2004, Science, 303, 1990). We explore whether the dynamical model, which successfully reproduces the beta Pictoris brightness profile (e.g., Augereau et al. 2001, A&A, 370, 447), could apply to AU Mic. Methods. We calculate the surface density profile of the AU Mic disk by performing the inversion of the near-IR and visible scattered light brightness profiles measured by Liu (2004, Science, 305, 1442) and Krist et al. (2005, AJ, 129, 1008), respectively. We discuss the grain properties by analysing the blue color of the disk in the visible (Krist et al. 2005) and by fitting the disk spectral energy distribution. Finally, we evaluate the radiation and wind forces on the grains. The impact of the recurrent X-ray and UV-flares on the dust dynamics is also discussed. Results. We show that irrespective of the mean scattering asymmetry factor of the grains, most of the emission arises from an asymmetric, collisionally-dominated region that peaks close to the surface brightness break around 35 AU. The elementary scatterers at visible wavelengths are found to be sub-micronic, but the inferred size distribution underestimates the number of large grains, resulting in sub-millimeter emissions that are too low compared to the observations. From our inversion procedure, we find that the V-to H-band scattering cross sections ratio increases outside 40 AU, in line with the observed color gradient of the disk. This behavior is expected if the grains have not been produced locally, but placed in orbits of high eccentricity by a size-dependent pressure force, resulting in a paucity of large grains beyond the outer edge of the parent bodies' disk. Because of the low luminosity of AU Mic, radiation pressure is inefficient to diffuse the smallest grains in the outer disk, even when the flares are taken into account. Conversely, we show that a standard, solar- like stellar wind generates a pressure force onto the dust particles that behaves much like a radiation pressure force. With an assumed dot{M} \simeq 3\times102} similar to \dot{M}_{\odot}, the wind pressure overcomes the radiation pressure, and this effect is enhanced by the stellar flares. This greatly contributes to populating the extended AU Mic debris disk and explains the similarity between the beta Pictoris and AU Mic brightness profiles. In both cases, the color gradient beyond 120 AU for beta Pictoris and 35 AU for AU Mic, is believed to be a direct consequence of the dust dynamics.
In this study, we focus on qualitative differences in the network structure and dynamics of natural as well as poly(butadiene) rubber in dependence of the cure system (sulfur/accelerator or organic ...peroxide) used in the vulcanization process. The spatial homogeneity of the distribution of chemical and physical cross-links in the network is assessed via the quantitative measurement of proton−proton residual dipolar couplings as measured by static multiple-quantum (MQ) NMR spectroscopy at low field. The experiment also provides information on the apparent correlation time of fast segmental fluctuations that dominate chain relaxation processes at lower temperature, for which we also find characteristic differences. Vulcanization via a radical mechanism (using organic peroxides) leads to networks with a high content of nonelastic defects (loops or dangling chains), a rather inhomogeneous distribution of cross-links, and modified (slower) local dynamics, as compared to networks obtained by sulfur vulcanization. These microstructural factors can be related with the well-known differences in the macroscopic properties of diene rubbers vulcanized with different cure systems.
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