Background
New‐onset chronic pain has been acknowledged as part of the post‐COVID‐19 condition. However, available fine‐grained data about its clinical phenotype, trajectories and main associated ...characteristics remain scarce. We described the distinct temporal evolutions of post‐COVID‐19 pain and their epidemiological and phenotypical features.
Methods
A prospective cross‐sectional study enrolled post‐COVID‐19 condition patients (i.e. who had persisting COVID‐19‐related symptoms over 30 days since their first positive laboratory test), whose COVID‐19 diagnosis had been supported by RT‐PCR of oral/nasopharyngeal swab or serology. They underwent in‐person evaluations with a structured interview, pain and quality‐of‐life‐related questionnaires and thorough physical examination. Chronic pain (CP) and probable neuropathic pain (NP) were defined according to IASP criteria.
Results
The present study included 226 individuals, 177 (78.3%) of whom presented over 3 months since their first COVID‐19 symptom. New‐onset pain occurred in 170 (75.2%) participants and was chronic in 116 (68.2%). A chronic course was associated with COVID‐19‐related hospitalization, new‐onset fatigue, lower cognitive performance, motor and thermal sensory deficits, mood and sleep impairments and overall lower quality‐of‐life levels. Probable NP occurred in only 7.6% new‐onset pain patients, and was associated with pain chronification, new‐onset fatigue, motor and thermal sensory deficits, mechanical allodynia and lower rates of SARS‐CoV‐2 vaccination. Previous CP was reported by 86 (38.1%) individuals and had aggravated after the infection in 66 (76.7%) of them, which was associated with orthostatic hypotension.
Conclusions
Post‐COVID pain phenomena follow different paths, which are associated with specific clinical and epidemiological features, and possibly distinct underlying mechanisms, prognostic and therapeutic implications.
Significance
COVID‐19‐related pain usually follows a chronic course and is non‐neuropathic. Its possible courses and phenotypes are associated with distinct clinical and epidemiological features. This suggests differing underlying mechanisms, which may have significant prognostic and therapeutic implications.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•Rapid determination of molecular weight of chitosanes was possible.•Single point determination of viscometric parameter for chitosanes was proposed.•Equations for quick viscometric measurements for ...chitosanes was evaluated.
A viscometric study was carried out at 25°C to assess the physical–chemical behavior in solution and the mean viscometric molar mass (M¯v) of chitosan solutions with different deacetylation degrees, in two solvent mixtures: medium 1—acetic acid 0.3mol/L and sodium acetate 0.2mol/L; and medium 2—acetic acid 0.1mol/L and sodium chloride 0.2mol/L. Different equations were employed, by graphical extrapolation, to calculate the intrinsic viscosities η and the viscometric constants, to reveal the solvent's quality: Huggins (H), Kraemer (K) and Schulz–Blaschke (SB). For single-point determination, the equations used were SB, Solomon–Ciuta (SC) and Deb–Chanterjee (DC), resulting in a faster form of analysis. The values of ̄M¯v were calculated by applying the equation of Mark–Houwink–Sakurada. The SB and SC equations were most suitable for single-point determination of η and ̄M¯v and the Schulz–Blachke constant (kSB), equal to 0.28, already utilized for various systems, can also be employed to analyze chitosan solutions under the conditions studied.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Premise of the Study
This study details the unusual synorganization of the staminate flower in wind‐pollinated urticalean rosids to add the missing pieces that complete the puzzle of the explosive ...mechanism of pollen release in this group.
Methods
Flower buds and flowers were analyzed using light and scanning electron microscopy.
Key Results
The pistillode, stamens, and sepals form a floral apparatus that explosively releases pollen to be carried by the wind. The anthers dehisce when the stamens are still inflexed on the floral bud and are enveloped by the sepals and supported by an inflated pistillode. The distension of the filaments presses the pistillode, which decreases the pressure exerted on the anthers by releasing the air accumulated internally through its apical orifice. The extended filaments and the dehiscent free anthers move rapidly outward from the center of the flower. This movement of the filaments is then blocked by the robust basally united sepals, which causes a rapid inversion of the anther position, thus hurling the pollen grains far from the flower. The pollen grains are released grouped by the mucilage produced in high quantity in the cells found in all floral organs.
Conclusions
The anatomical structure of the pistillode and the finding of mucilaginous cells are the main features that help in the understanding the explosive mechanism of pollen release in urticalean rosids. The pistillode can be considered an exaptation because it was evolved later to provide a new role in the plant, optimizing male fitness.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
RESUMEN Antecedentes: El dolor crónico de nueva aparición se considera que forma parte de la condición o afección post-COVID-19. Sin embargo, los datos detallados existentes sobre el fenotipo ...clínico, las trayectorias y las principales características asociadas siguen siendo escasos. Describimos las distintas evoluciones temporales del dolor post-COVID-19 y sus rasgos epidemiológicos y fenotípicos. Métodos: Estudio prospectivo y transversal de pacientes con afección post-COVID-19 (es decir, con síntomas persistentes relacionados con la COVID-19 durante 30 días desde la primera prueba positiva de laboratorio) cuyo diagnóstico de COVID-19 estuviera basado en la RT-PCR de un frotis oral/nasofaríngeo o una serología. Se sometieron a evaluaciones presenciales mediante una entrevista estructurada, cuestionarios de dolor y calidad de vida y una exploración física exhaustiva. El dolor crónico (DC) y el dolor neuropático (DN) probablemente se definieron conforme a los criterios IASP. Resultados: El presente estudio incluyó 226 individuos, 177 (78,3 %) de los cuales se presentaron pasados más de 3 meses desde el primer síntoma de COVID-19. Tenían dolor de nueva aparición 170 (75,2 %) de los participantes y dolor crónico 116 (68,2 %). El curso crónico se asociaba a hospitalización por COVID-19, fatiga de nueva aparición, menor rendimiento cognitivo, déficits motores y sensitivos térmicos, alteraciones del ánimo y el sueño, y niveles generalmente inferiores de calidad de vida. El DN probable afectaba a solo el 7,6 % de los pacientes con dolor de nueva aparición y se asociaba a cronificación del dolor, fatiga de nueva aparición, déficits motores y de sensación térmica, alodinia mecánica y tasas menores de vacunación frente al SARS-CoV-2. Referían DC previo 86 (38,1 %) individuos, y este había empeorado tras la infección en 66 (76,7 %) de ellos, lo que se asociaba a hipotensión ortostática. Conclusiones: Los fenómenos dolorosos post-COVID siguen diferentes trayectorias que se asocian a rasgos clínicos y epidemiológicos específicos, y posiblemente a distintos mecanismos de base y diferentes implicaciones pronósticas y terapéuticas. Significado: El dolor relacionado con la COVID-19 sigue normalmente un curso crónico y no es neuropático. Los posibles cursos y fenotipos se asocian a rasgos clínicos y epidemiológicos distintos. Esto sugiere que los mecanismos de base difieren, lo que podría tener implicaciones pronósticas y terapéuticas importantes.
T. cruzi II strains accumulate more 8-oxoguanine in the kDNA after hydrogen peroxide-induced 18 oxidative stress than T. cruzi I strains. NT: untreated; T: treated. Display omitted
▶ Distinct levels ...of DNA mismatch repair activity are found among T. cruzi strains. ▶ In T. cruzi and T. brucei, MSH2 has a mitochondrial function involved in the response to oxidative stress.
Components of the DNA mismatch repair (MMR) pathway are major players in processes known to generate genetic diversity, such as mutagenesis and DNA recombination. Trypanosoma cruzi, the protozoan parasite that causes Chagas disease has a highly heterogeneous population, composed of a pool of strains with distinct characteristics. Studies with a number of molecular markers identified up to six groups in the T. cruzi population, which showed distinct levels of genetic variability. To investigate the molecular basis for such differences, we analyzed the T. cruzi MSH2 gene, which encodes a key component of MMR, and showed the existence of distinct isoforms of this protein. Here we compared cell survival rates after exposure to genotoxic agents and levels of oxidative stress-induced DNA in different parasite strains. Analyses of msh2 mutants in both T. cruzi and T. brucei were also used to investigate the role of Tcmsh2 in the response to various DNA damaging agents. The results suggest that the distinct MSH2 isoforms have differences in their activity. More importantly, they also indicate that, in addition to its role in MMR, TcMSH2 acts in the parasite response to oxidative stress through a novel mitochondrial function that may be conserved in T. brucei.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The dependence of the adsorption behavior toward Zn²⁺ and Cd²⁺ on the synthesis conditions of dithiocarbamate styrenic resins was investigated. We synthesized styrene-divinylbenzene copolymers with ...different kinds of porous structures by varying the divinylbenzene (DVB)-to-styrene ratio and the dilution degree of the monomers with n-heptane. The porous structure of these materials was characterized. The introduction of the dithiocarbamate moiety on the copolymers followed a synthetic pathway based on the nitration reaction, reduction of the nitro group to the amino one, and finally, the addition of the amino group to CS₂. All of the synthesis steps were monitored by Fourier transform infrared spectroscopy. Only the addition reaction to CS₂ was greatly influenced by the copolymer porosity. The effect of the dilution degree on the reaction extension was more pronounced than the effect of the DVB content. The more porous materials with higher dithiocarbamate contents adsorbed a higher amount of ions in a faster way, with Zn²⁺ being preferable over Cd²⁺ ions. The difference between the Zn²⁺ and Cd²⁺ adsorption rates was enhanced with the copolymer porosity, and also enhanced was the difference between the amounts of ions adsorbed by the copolymer; this suggested that the selectivity toward these ions could be controlled by the copolymer porous structure.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Styrene-divinylbenzene (S-DVB) copolymers with different kinds of porous structures were synthesized by aqueous suspension polymerization using n-heptane as the pore forming agent. The amount of this ...solvent (monomer dilution degree) and the DVB content in the organic phase were varied. The combination of three different dilution degree values and three DVB contents yielded three series of copolymers with a variety of porous structures. The three series were composed by copolymers with pore diameters (D) in the following ranges: D < 500 Å, 500 < D < 1000 Å, and D > 1000 Å, respectively. The effect of synthesis conditions on the pore size distribution and on the copolymer matrix rigidity was evaluated. These copolymers were submitted to a chloromethylation reaction with a paraformaldehyde/gaseous HCl mixture in the presence of zinc chloride as a Lewis acid catalyst and 1,2-dichloroethane as solvent. The effect of the copolymer porosity on the chloromethylation reaction extension was evaluated. It was possible to observe that a gel copolymer with a high swelling capacity in the reaction medium achieved the same chloromethylation yield observed for a high porous copolymer. This result thus indicates that, in the case of the chloromethylation reaction studied here, the high swelling capacity of the gel copolymer can counterbalance its limited surface area, turning this type of polymer structure as reactive as a macroporous one.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The influence of the crosslinking degree and monomer dilution with a porogenic agent on the binding of copper(II) by four amidoxime chelating resins was studied by EPR. The amidoxime resins were ...characterized by FTIR and surface area measurements, and were loaded with Cu(II). Room temperature EPR spectra of the Cu(II)-loaded resins were best simulated with two Cu(II) species, namely Species 1, corresponding to isolated Cu(II) sites, and Species 2, whose broad lines where assigned to clustering of Cu(II) centers. All the spectra also presented a pattern of ligand hyperfine lines (
a
N
=
1.4
mT) corresponding to two magnetically equivalent nitrogen nuclei bonded to the Cu(II) center. The concentration and distribution of amidoxime groups in the polymer matrix influenced the environment of Cu(II) ions. The formation of Cu(II) clusters was improved by two factors: high pore diameter and high amidoxime group content of the chelating resins.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This study focuses on the floral development of Copaifera langsdorffii to elucidate uncertain features in its floral morphology, such as the tetramerous calyx, lack of petals, blackened anthers and ...their supposed sterility, as well as polyembryony. Buds and flowers were dissected and prepared for examination under scanning electron and light microscopes. The floral apex initiates two bracteoles, five sepals, five petals, five outer stamens, five inner stamens, and one carpel. Order is helical for sepals, reversed unidirectional for the petals, and unidirectional for two whorls of stamens. The tetramerous calyx results from the union of two adaxial sepal primordia, which forms one large sepal and three other smaller sepals. Although the flower lacks petals, the petal primordia are initiated but do not elongate like the other floral organs, remaining as petal rudiments. Ten stamens are formed in two distinct whorls. Formation within each whorl is almost simultaneous, and the inner whorl is formed shortly after the outer. During organ elongation, the inner stamen primordia bases are reoriented outward, resulting in a single whorl of stamens. The darkened anthers have viable pollen grains. Thus, there is no relation between sterility and the dark coloration of the anthers. No signs of extranumerary embryos are observed; therefore, polyembryony is not confirmed. Although studies on floral development of Detarieae have been reported, few Neotropical genera of the tribe (such as Copaifera) have been studied.
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BFBNIB, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Chelating resins for mercury adsorption were prepared by grafting polyacrylamide chains onto styrene–divinylbenzene (Sty–DVB) copolymers by applying gamma radiation. Sty–DVB copolymers were ...synthesized by aqueous suspension polymerization employing different synthesis conditions. The copolymers were characterized by apparent density, surface area, pore size distribution and swelling capacity. The copolymers were irradiated using a
60Co-γ source at room temperature in the presence of acrylamide solution in methanol. The grafting reaction was evaluated with the aid of elemental analysis, FTIR and thermogravimetric analysis (TGA). Hg(II) uptake measurements were carried out in batch experiments. The results showed that these resins can be successfully used for Hg(II) adsorption at ppm levels. The porosity degree of the copolymers influences the grafting yield as well as the Hg(II) complexation capacity of the chelating resins.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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