Buchbesprechungen

Ohne Zusammenfassung     

Der Muskuläre Cyclus der Menschlichen Gebärmutter

Ohne Zusammenfassung     

Pretest and change score intercorrelations in the validation of behavioral measures of openness

Two behavioral measures of openness (a miniature situations test and a structured self-disclosure interview), two self-report measures of openness (the Dogmatism Scale and the Experience Inventory), and the Ego-strength Scale were administered to 50 Ss on two different occasions spaced several weeks apart. One of the behavioral measures, the miniature situations test, correlated positively with the other measures of openness on the pretest. With regard to change scores across the two sessions, the behavioral measures correlated positively with each other and negatively with the self-report measures of openness and with the Ego-strength Scale. These results were interpreted as supporting the theoretical supposition that behavioral measures are most suitable for the measurement of short-term change in openness.     

From the Cover: Strain history dependence of the nonlinear stress response of fibrin and collagen networks

We show that the nonlinear mechanical response of networks formed from un–cross-linked fibrin or collagen type I continually changes in response to repeated large-strain loading. We demonstrate that this dynamic evolution of the mechanical response arises from a shift of a characteristic nonlinear stress–strain relationship to higher strains. Therefore, the imposed loading does not weaken the underlying matrices but instead delays the occurrence of the strain stiffening. Using confocal microscopy, we present direct evidence that this behavior results from persistent lengthening of individual fibers caused by an interplay between fiber stretching and fiber buckling when the networks are repeatedly strained. Moreover, we show that covalent cross-linking of fibrin or collagen inhibits the shift of the nonlinear material response, suggesting that the molecular origin of individual fiber lengthening may be slip of monomers within the fibers. Thus, a fibrous architecture in combination with constituents that exhibit internal plasticity creates a material whose mechanical response adapts to external loading conditions. This design principle may be useful to engineer novel materials with this capability.     

The dystrophin gene and cognitive function in the general population

The aim of our study is to investigate whether single-nucleotide dystrophin gene (DMD) variants associate with variability in cognitive functions in healthy populations. The study included 1240 participants from the Erasmus Rucphen family (ERF) study and 1464 individuals from the Rotterdam Study (RS). The participants whose exomes were sequenced and who were assessed for various cognitive traits were included in the analysis. To determine the association between DMD variants and cognitive ability, linear (mixed) modeling with adjustment for age, sex and education was used. Moreover, Sequence Kernel Association Test (SKAT) was used to test the overall association of the rare genetic variants present in the DMD with cognitive traits. Although no DMD variant surpassed the prespecified significance threshold (P<1 × 10⁻⁴), rs147546024:A>G showed strong association (β=1.786, P-value=2.56 × 10⁻⁴) with block-design test in the ERF study, while another variant rs1800273:G>A showed suggestive association (β=−0.465, P-value=0.002) with Mini-Mental State Examination test in the RS. Both variants are highly conserved, although rs147546024:A>G is an intronic variant, whereas rs1800273:G>A is a missense variant in the DMD which has a predicted damaging effect on the protein. Further gene-based analysis of DMD revealed suggestive association (P-values=0.087 and 0.074) with general cognitive ability in both cohorts. In conclusion, both single variant and gene-based analyses suggest the existence of variants in the DMD which may affect cognitive functioning in the general populations.     

Rivaroxaban reversal with prothrombin complex concentrate or tranexamic acid in healthy volunteers

Essentials

• Specific reversal agents for managing severe factor Xa inhibitor‐associated bleeding are lacking.
• We assessed 4‐factor‐prothrombin complex concentrate (4F‐PCC) and tranexamic acid (TXA).
• 4F‐PCC, but not TXA, reduced the prothrombin time and increased endogenous thrombin potential.
• These agents may be viable options for reversal of therapeutic doses of rivaroxaban.

Summary

Background

Oral activated factor X inhibitors such as rivaroxaban are widely used, but specific reversal agents are lacking. Although four‐factor prothrombin complex concentrate (4F‐PCC) and tranexamic acid (TXA) are sometimes used to manage serious bleeding, their efficacy is unknown. Prior studies in healthy subjects taking rivaroxaban revealed that 4F‐PCC partially reverses the prolonged prothrombin time (PT), and fully restores the endogenous thrombin potential (ETP). The effect of TXA has not been evaluated.

Methods

In this double‐blind, parallel‐group study, 147 healthy volunteers given rivaroxaban 20 mg twice daily for 3 days were randomized after their morning dose on day 4 to receive intravenous 4F‐PCC (50 IU kg^?1), TXA (1.0 g), or saline. Standardized punch biopsies were performed at baseline and after 4F‐PCC, TXA or saline administration. Reversal was assessed by measuring bleeding duration and bleeding volume at biopsy sites, and by determining the PT and ETP.

Results

As compared with saline, 4F‐PCC partially reversed the PT and completely reversed the ETP, whereas TXA had no effect. Neither 4F‐PCC nor TXA reduced bleeding duration or volume. All treatments were well tolerated, with no recorded adverse events.

Conclusions

Although 4F‐PCC reduced the PT and increased the ETP in volunteers given supratherapeutic doses of rivaroxaban, neither 4F‐PCC nor TXA influenced punch biopsy bleeding.

     

Constructing the meaning of ultrasound viewing in abortion care

As ultrasound scanning becomes increasingly routine in abortion care, scholars and activists have forwarded claims about how viewing the ultrasound image will affect pregnant women seeking abortion, speculating that it will dissuade them from abortion. These accounts, however, fail to appreciate how viewing is a social process. Little research has investigated how ultrasound workers navigate viewing in abortion care. We draw on interviews with twenty‐six ultrasound workers in abortion care for their impressions and practices around ultrasound viewing. Respondents reported few experiences of viewing dissuading women from abortion, but did report that it had an emotional effect on patients that they believed was associated with gestational age. These impressions informed their practices, leading many to manage patient viewing based on the patient's gestational age. Other aspects of their accounts, however, undercut the assertion that the meaning of ultrasound images is associated with gestation and show the pervasiveness of cultural ideas associating developing foetal personhood with increasing gestational age. Findings demonstrate the social construction of ultrasound viewing, with implications in the ongoing contestation over abortion rights in the US.     

Postmenopausal estrogen administration suppresses muscle sympathetic nerve activity

The activity of the sympathetic nervous system shows gender-specific differences with lower sympathoneural activity to the muscle vascular bed in women compared with men, with this difference vanishing after menopause. The present study tested the hypothesis that estrogen exerts regulatory influence on the autonomic nervous system in postmenopausal women. Eleven healthy postmenopausal women (age, 58.5 +/- 1.0 yr; mean +/- SEM) were studied in a randomized double-blind crossover protocol with transdermal administration of 100 microgram/day estradiol (E(2)) or placebo (P) for 2 days. Muscle sympathetic activity (MSA), blood pressure, and heart rate were recorded at rest and during sympathoexcitatory maneuvers (apnea, cold pressor test). E(2) administration significantly increased serum E(2) to physiological levels (E(2), 469.5 +/- 51.5; P, 34.8 +/- 2.2 pmol/L; P < 0.05) and significantly lowered MSA (E(2), 30.1 +/- 3.0 vs. P 37.7 +/- 3.1 bursts/min; P < 0.05). At the same time, blood pressure and heart rate were not affected. MSA was significantly enhanced during apnea and the cold pressure test, and this physiological response to the maneuvers was not changed after estrogen supplementation. In conclusion, elevation of low postmenopausal estrogen levels to physiological premenopausal levels by transdermal E(2) administration supresses MSA. This effect is most likely the consequence of a direct E(2) effect on central nervous autonomic centers, which could explain the gender-specific differences in sympathetic outflow to the muscle vascular bed. The sympathoinhibitory estrogen effects could be important for beneficial cardiovascular effects of estrogen replacement therapy in postmenopausal women.