Risk of fetal loss after chorionic villus sampling in twin pregnancy derived from propensity score matching analysis

OBJECTIVE

To estimate the risk of fetal loss associated with chorionic villus sampling (CVS) in twin pregnancy, using propensity score analysis.

METHODS

This was a multicenter cohort study of women with twin pregnancy undergoing ultrasound examination at 11-13 weeks' gestation, performed in eight fetal medicine units in which the leadership were trained at the Harris Birthright Research Centre for Fetal Medicine in London, UK, and in which the protocols for screening, invasive testing and pregnancy management are similar. The risk of death of at least one fetus was compared between pregnancies that had and those that did not have CVS, after propensity score matching (1:1 ratio). This procedure created two comparable groups by balancing the maternal and pregnancy characteristics that lead to CVS being performed, similar to how randomization operates in a randomized clinical trial.

RESULTS

The study population of 8581 twin pregnancies included 445 that had CVS. Death of one or two fetuses at any stage during pregnancy occurred in 11.5% (51/445) of pregnancies in the CVS group and in 6.3% (515/8136) in the non-CVS group (P < 0.001). The propensity score algorithm matched 258 cases that had CVS with 258 non-CVS cases; there was at least one fetal loss in 29 (11.2%) cases in the CVS group and in 35 (13.6%) cases in the matched non-CVS group (odds ratio (OR), 0.81; 95% CI, 0.48-1.35; P = 0.415). However, there was a significant interaction between the risk of fetal loss after CVS and the background risk of fetal loss; when the background risk was higher, the risk of fetal loss after CVS decreased (OR, 0.46; 95% CI, 0.23-0.90), while, in pregnancies with a lower background risk of fetal loss, the risk of fetal loss after CVS increased (OR, 2.45; 95% CI, 0.95-7.13). The effects were statistically significantly different (P-value of the interaction = 0.005). For a pregnancy in which the background risk of fetal loss was about 6% (the same as in our non-CVS population), there was no change in the risk of fetal loss after CVS, but, when the background risk was more than 6%, the posterior risk was paradoxically reduced, and when the background risk was less than 6%, the posterior risk increased exponentially; for example, if the background risk of fetal loss was 2.0%, the relative risk was 2.8 and the posterior risk was 5.6%.

CONCLUSION

In twin pregnancy, after accounting for the risk factors that lead to both CVS and spontaneous fetal loss and confining the analysis to pregnancies at lower prior risk, CVS seems to increase the risk of fetal loss by about 3.5% above the patient's background risk. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Lewis Acid Enabled Copper-Catalyzed Asymmetric Synthesis of Chiral β-Substituted Amides

Here we report that readily available silyl- and boron-based Lewis acids in combination with chiral copper catalysts are able to overcome the reactivity issues of unactivated enamides, known as the least reactive carboxylic acid derivatives, toward alkylation with organomagnesium reagents. Allowing unequaled chemo-reactivity and stereocontrol in catalytic asymmetric conjugate addition to enamides, the method is distinguished by its unprecedented reaction scope, allowing even the most challenging and synthetically important methylations to be accomplished with good yields and excellent enantioselectivities. This catalytic protocol tolerates a broad temperature range (−78 °C to ambient) and scale up (10 g), while the chiral catalyst can be reused without affecting overall efficiency. Mechanistic studies revealed the fate of the Lewis acid in each elementary step of the copper-catalyzed conjugate addition of Grignard reagents to enamides, allowing us to identify the most likely catalytic cycle of the reaction.

Diagnostic criteria of white coat hypertension (WCH): consequences for the implications of WCH for target organs

In a sample comprising 51 normotensive subjects and 51 subjects with in-clinic arterial hypertension [blood pressures (BPs) > or = 140/90 mmHg), we investigated the prevalence of target organ damage [left ventricular hypertrophy (LVH) and retinal vasculopathy] in white coat hypertension (WCH) groups defined using: (a) the "optimal ambulatory BP" criterion of the Seventh International Consensus Conference (in-clinic BPs >140/90 mmHg, daytime mean BPs < 130/80 mmHg) and (b) the "normal ambulatory BP" criterion proposed in 1997 by Verdecchia and co-workers (in-clinic BPs >140/ 90 mmHg, daytime mean BPs < 135/85 mmHg), and we compared the results with those obtained for the normotensive group and for a WCH group defined as in a 1996 study of the same data. We found that the newer criteria did not alter the conclusions reached in 1996: namely, that WCH constitutes a state of risk intermediate between normotension and sustained hypertension, which demands in-depth evaluation and active monitoring, if not immediate therapy. We also found that when the WCH group was defined as those patients with in-clinic BPs > or = 140/90 mmHg and 24-h mean BPs < 121/78 mmHg, the prevalence of target organ damage was similar to that found in the control group. We conclude that if WCH status is to imply absence of elevated risk of target organ damage, then the ambulatory BP threshold defining WCH should be lower than the upper limit of ambulatory BPs among subjects who are normotensive in the clinic. The desirability of predicting target organ damage in both hypertensive and normotensive subjects using criteria combining in-clinic BPs, daytime mean ambulatory BPs and night-time mean ambulatory BPs is suggested.

Free-Radical Cyclizations onto Differently Substituted 1,2,3-Triazoles Installed in Sugar Templates

The synthesis and manipulation of differently substituted 1,2,3-triazoles (7-11 and 12-16) installed in sugar templates gave compounds 29-34 and 44-50, after reaction with tributyltin hydride or tris(trimethylsilyl)silane. Following standard procedures compound 44 was transformed into piperidinose derivative 54. These compounds are chiral, useful building blocks for the synthesis of glycosidase inhibitors of the fused-azole piperidinose type.

Iontophoretic permselectivity of mammalian skin: characterization of hairless mouse and porcine membrane models

PURPOSE

To evaluate the transport number of Na+, and the isoelectric point, of two skin membranes frequently used for iontophoretic in vitro research.

METHODS

Na+ transport numbers were determined by the Hittorf method or by the measurement of membrane potential. The skin isoelectric point was deduced from the electroosmosis of mannitol (a polar non-electrolyte) as a function of pH.

RESULTS

The Na+ transport number across porcine skin, like that for hairless mouse, indicated a modest cation permselectivity. Consistent with this observation, the isoelectric points of porcine and hairless mouse skin were determined to be in the ranges of 3.5-3.75 and 4.5-4.6, respectively. That is, at physiological pH, both of these model membranes supports a net negative charge.

CONCLUSIONS

The permselective properties of porcine and hairless mouse skin are similar (but with the porcine membrane having apparently fewer basic or more weakly-acidic groups than that of the mouse) and consistent with the characteristics, which have been deduced elsewhere, of human skin.