Daily fluctuations in occupation with and worry about COVID-19.

In the first week after the first COVID-19 patient was reported in the Netherlands, we conducted a pre-registered momentary assessment study (7 surveys per day, 50 participants, 7 days) to study the dynamic relationship between individuals' occupation with and worries about COVID-19 in daily life, and the moderating role of neuroticism in this relationship. At the group level, higher scores on occupation and worry co-occurred, and occupation predicted worry 1 h later, but not vice versa. There were substantial individual differences in the magnitudes and directions of the effects. For instance, occupation with COVID-19 was related to increases in worry for some but decreases in worry for others. Neuroticism did not predict any of these individual differences in the links between worry and occupation. This study suggests that it is important to go beyond group-level analyses and to account for individual differences in responses to COVID-19.

The Longitudinal Association between Self-esteem and Depressive Symptoms in Adolescents: Separating between-person effects from within-person effects.

Many longitudinal studies have investigated whether self-esteem predicts depressive symptoms (vulnerability model) or the other way around (scar model) in adolescents. The most common method of analysis has been the Cross-lagged Panel Model (CLPM). The CLPM does not separate between-person effects from within-person effects, making it unclear whether the results from previous studies actually reflect the within-person effects, or whether they reflect differences between people. We investigated the associations between self-esteem and depressive symptoms at the within-person level, using Random Intercept Cross-Lagged Panel Models (RI-CLPM). To get an impression of the magnitude of possible differences between the RI-CLPM and CLPM, we compared the results of both models. We used data from three longitudinal adolescent samples (age range 7-18; Study 1: N=1,948; Study 2: N=1,455; Study 3: N=316). Intervals between the measurements were 1-1.5 years. Single-paper meta-analyses showed support for small within-person associations from self-esteem to depressive symptoms, but not the other way around, thus only providing some support for the vulnerability model. The cross-lagged associations in the aggregated RI-CLPM and CLPM showed similar effect sizes. Overall, our results show that over 1-1.5 year time intervals, low self-esteem may negatively influence depressive symptoms over time within adolescents, but only weakly so.

Adolescent Loneliness and Social Skills: Agreement and Discrepancies Between Self-, Meta-, and Peer-Evaluations.

Lonely adolescents report that they have poor social skills, but it is unknown whether this is due to an accurate perception of a social skills deficit, or a biased negative perception. This is an important distinction, as actual social skills deficits require different treatments than biased negative perceptions. In this study, we compared self-reported social skills evaluations with peer-reported social skills and meta-evaluations of social skills (i.e., adolescents' perceptions of how they believe their classmates evaluate them). Based on the social skills view, we expected negative relations between loneliness and these three forms of social skills evaluations. Based on the bias view, we expected lonely adolescents to have more negative self- and meta-evaluations compared to peer-evaluations of social skills. Participants were 1342 adolescents (48.64 % male, M age = 13.95, SD = .54). All classmates rated each other in a round-robin design to obtain peer-evaluations. Self- and meta-evaluations were obtained using self-reports. Data were analyzed using polynomial regression analyses and response surface modeling. The results indicated that, when self-, peer- and meta-evaluations were similar, a greater sense of loneliness was related to poorer social skills. Loneliness was also related to larger discrepancies between self- and peer-evaluations of loneliness, but not related to the direction of these discrepancies. Thus, for some lonely adolescents, loneliness may be related to an actual social skills deficit, whereas for others a biased negative perception of one's own social skills or a mismatch with the environment may be related to their loneliness. This implies that different mechanisms may underlie loneliness, which has implications for interventions.

Thermal and photochemical solvolysis of (E)- and (Z)-2-phenyl-1-propenyl(phenyl)iodonium tetrafluoroborate: benzenium and primary vinylic cation intermediates.

The thermal and photochemical solvolysis of the two stereoisomeric 2-phenyl-1-propenyl(phenyl)iodonium tetrafluoroborates has been investigated in alcoholic solvents of varying nucleophilicity. The product profiles and rates of product formation in the thermal reaction are all compatible with a mechanism involving cleavage of the vinylic C-I bond assisted by the group in the trans position (methyl or phenyl), always leading to rearranged products. Depending on the nucleophilicity of the solvent, the primarily formed cations may or may not further rearrange to more stable isomers. The less reactive Z compound also yields some unrearranged vinyl ether product in the more nucleophilic solvents via an in-plane S(N)2 mechanism. The mechanism of the photolysis involves direct, unassisted cleavage of the vinylic, and aromatic, C-I bond in an S(N)1 mechanism. This produces a primary vinyl cation, which is partially trapped prior to rearrangement in methanol. The unrearranged vinyl ethers are mainly formed with retention of configuration via a lambda3-iodonium/solvent complex in an S(N)i mechanism. Thermal and photochemical solvolyses of iodonium salts are complementary techniques for the generation of different cation intermediates from the same substrate.

Molecular analysis of naturally occuring ermC-encoding plasmids in staphylococci isolated from animals with and without previous contact with macrolide/lincosamide antibiotics.

A total of 16 epidemiologically unrelated macrolide-resistant staphylococcal isolates of various animal origins were investigated for the molecular basis of macrolide resistance with respect to previous contact of their host animals with macrolides and lincosamides. All isolates carried ermC-encoding plasmids of 2.3-4.0 kbp. The eight plasmids of staphylococci from animals which had not received macrolides or lincosamides showed inducible ermC gene expression and did not exhibit alterations in the ermC regulatory region. The remaining eight plasmids expressed the ermC gene constitutively. Six of these plasmids were from staphylococci from animals which had received tylosin or spiramycin as feed additives or lincomycin for therapeutic purposes. All constitutively expressed ermC genes revealed either sequence deletions or sequence duplications in their ermC regulatory region, as detected by a PCR assay and by sequence analysis. These sequence deletions and duplications found in naturally occurring plasmids corresponded closely to the mutations seen in the ermC-encoding plasmids after growth of an inducibly resistant strain in the presence of non-inducing macrolides or lincosamides under in vitro conditions.

Tandem duplication in ermC translational attenuator of the macrolide-lincosamide-streptogramin B resistance plasmid pSES6 from Staphylococcus equorum.

A tandem duplication of 23 bp in the ermC gene translational attenuator of plasmid pSES6 from Staphylococcus equorum which mediated constitutive resistance to macrolide-lincosamide-streptogramin B antibiotics was identified. This duplication included the ribosome binding site for the ermC gene as well as the first 5 bp of the ermC coding sequence. It was postulated that this sequence duplication affects the possible RNA conformations so that the ribosome binding site for ErmC synthesis is readily accessible to the ribosomes and thus constitutive expression of the ermC gene occurs.

Irreversible binding with biological macromolecules and effects in bacterial mutagenicity tests of the radical cation of promethazine and photoactivated promethazine. Comparison with chlorpromazine.

The irreversible binding of the radical cation of promethazine (PMZ+.) to DNA and protein in vitro and bacterial macromolecules in situ has been studied. Binding experiments were performed with synthesized [35S] promethazine. The results are compared to those with the chlorpromazine radical cation (CPZ+.). Secondary reaction products which result from fission of the alkylamino side chain are involved in the macromolecular binding of PMZ+. Compared to CPZ+. the covalent DNA binding of PMZ+. is significantly less. A larger amount of PMZ+. binds to single-stranded DNA than to double-stranded DNA. The extent of binding to proteins and RNA is of the same order as that of CPZ+. Bacterial mutagenicity tests show that the low genotoxicity of PMZ+. is related to the low DNA binding. The bacterial cytotoxicity is possibly related to the covalent protein binding. Similar results have been obtained with photoactivated promethazine (PMZ) and chlorpromazine (CPZ). The role of radical cations in the photosensitization and metabolic activation of phenothiazine drugs is discussed.

Photosensitized irreversible binding of estrone to protein via a hydroperoxide intermediate: an explanation of (photo-) allergic side-effects of estrogens.

After irradiation (lambda greater than 425 nm) for 15 min of a solution of [4-14C]-estrone, albumin and the photosensitizer hematoporphyrin in phosphate buffer, more than 30% of the radioactivity could not be extracted. When the protein was added after irradiation, irreversible binding also occurred. Sephadex gel filtration showed that the radiolabel was bound to albumin as well as to the photosensitizer. A 10 beta-hydroperoxide is the reactive intermediate in this binding. Inasmuch as phenolic steroids coupled to proteins have been used for the induction of estrogenic-specific antibodies, the irreversible binding observed between estrone and albumin by photosensitization might be an explanation for (photo)allergic disorders associated with estrogens.

Interaction of the photosensitization products of oestrone with DNA: comparison with the horseradish peroxidase catalyzed reaction.

The interaction with DNA of [4-14C]oestrone upon photosensitization with hematoporphyrin (HP) as a photosensitizer has been investigated. By means of Sephadex LH-20 gel filtration and extraction with dichloromethane it was found that, after irradiation (lambda greater than 425 nm) of a solution of HP, DNA and [4-14C]oestrone 21% of the radiolabel was associated with DNA. If DNA was added after irradiation 23% was bound to DNA, whereas 25% of the oestrone remained after photoreaction under the conditions applied. The binding occurs via the reactive 10 beta-hydroperoxy-1,4-estradien-3,17-dione, which is the only product after photosensitization of oestrone. The hydroperoxide has a strong interaction with DNA compared with that of other steroids. By repeated precipitation with 5 M NaCl and ethanol the association can be broken. It is reported, that binding of oestrone to protein induced by both photosensitization and horseradish peroxidase (HRPO)/H2O2 is irreversible, but that the amount of binding to DNA is dependent on the method of determination. However, neither the hydroperoxide nor its reduced product, a p-quinol, is intermediate or product in the HRPO catalyzed reaction of oestrogens. The tight association of the hydroperoxide product of oestrone with DNA, which may proceed via hydrogen bonding between the -OOH group and oxygen atoms of the backbone phosphate groups or of the furanose ring, might be a cause of chemical modification of DNA and of mutagenic effects.

Irreversible Binding of Norethisterone to Human Serum Protein Induced by UV-B Light.

In as much as oral contraceptive ingestion has been associated with photoallergic effects, the irreversible binding of 4-(14)C-norethisterone to proteins catalyzed by UV-B light (290-320 nm) was investigated. Irreversible binding to a human plasma protein mixture and to albumin of the radiolabeled progestogen was linear for 40min, when mixtures of protein and steroid were irradiated with UV-B light. Approximately 16 % of the radiolabel was irreversibly bound under the conditions of the assay. Irreversible binding also occurred, when proteins were added several hours after irradiation. Preliminary experiments in rats administered 4-(14)C-norethisterone also indicate the formation in skin and liver of irreversibly bound adducts under photoreactive conditions. Such reactions may in part be responsible for some of the side-effects associated with oral contraceptive use.