Sexual Orientation in Twins: Evidence That Human Sexual Identity May Be Determined Five Days Following Fertilization.

Human same-sex sexual attraction has been recorded from the beginning of written history. It remains a controversial topic, but recent theories favor prenatal influences. A paradox is the occurrence of same-sex orientation in twins in that there is a higher level of concordance in monozygous twins compared to that in dizygous twins or non-twin siblings. If sexual orientation was entirely genetically determined monozygous twins would be expected to have identical sexual inclinations. Monozygous twins have twice the incidence of sexual concordance in comparison to dizygous twins but a third of these pairs have different sexual identities. An explanation for this disparity may lie in the time an embryo splits to form two separate fetuses. If splitting occurs early in twin development each twin may develop his or her own sexual identity; splitting occurring later results in twins that have the same sexual dispositions. A possible process for such determination may be in the mitochondria, with universal maternal inheritance of a proportion of normal functioning but alternate mitochondria. Variation in the distribution of these mitochondria in neural precursor cells becomes a mechanism for the development of intrinsic sexual orientation and for the spectrum of human sexual inclinations. The timing of embryonic splitting may be determined from the examination of fetal membranes, and the concept of early fetal sexual orientation is open to support or disproval.

Influence of variations in systemic blood flow and pressure on cerebral and systemic oxygen saturation in cardiopulmonary bypass patients.

BACKGROUND: Although both pressure and flow are considered important determinants of regional organ perfusion, the relative importance of each is less established. The aim of the present study was to evaluate the impact of variations in flow, pressure, or both on cerebral and whole-body oxygen saturation. METHODS: Thirty-four consenting patients undergoing elective cardiac surgery on cardiopulmonary bypass were included. Using a randomized cross-over design, four different haemodynamic states were simulated: (i) 20% flow decrease, (ii) 20% flow decrease with phenylephrine to restore baseline pressure, (iii) 20% pressure decrease with sodium nitroprusside (SNP) under baseline flow, and (iv) increased flow with baseline pressure. The effect of these changes was evaluated on cerebral (Sc(O2)) and systemic (Sv(O2)) oxygen saturation, and on systemic oxygen extraction ratio (OER). Data were assessed by within- and between-group comparisons. RESULTS: Decrease in flow was associated with a decrease in [from 63.5 (7.4) to 62.0 (8.5) %, P<0.001]. When arterial pressure was restored with phenylephrine during low flow, Sc(O2) further decreased from 61.0 (9.7) to 59.2 (10.2) %, P<0.001. Increase in flow was associated with an increase in Sc(O2) from 62.6 (7.7) to 63.6 (8.9) %, P=0.03, while decreases in pressure with the use of SNP did not affect Sc(O2). Sv(O2) was significantly lower (P<0.001) and OER was significantly higher (P<0.001) in the low flow arms. CONCLUSIONS: In the present elective cardiac surgery population, Sc(O2) and Sv(O2) were significantly lower with lower flow, regardless of systemic arterial pressure. Moreover, phenylephrine administration was associated with a reduced cerebral and systemic oxygen saturation.

[Zuclopenthixol acetate and haloperidol in acute psychoses. Results of the AMDP subgroup in a multicenter Belgian study]. / L'acétate de zuclopenthixol et l'halopéridol dans la psychose aigüe. Résultats du sous-groupe AMDP d'une étude multicentrique belge.

The efficacy of i.m. cis(Z)-clopenthixol in aggressive, agitated and delusional patients is well established but it necessitates, as for all other parenteral neuroleptics, several injections daily. Zuclopenthixol acetate is the first injectable neuroleptic characterized simultaneously by a short latency of action (2-3 h) and by a long duration of action (2-3 days). Within the frame of a Belgian multicentre study of zuclopenthixol acetate and haloperidol, a group of French-speaking psychiatrists added the AMDP scales to the basic protocol. The results of this AMDP subsample of 20 Acetate vs. 13 Haloperidol patients do not allow the demonstration of statistically significant differences between both neuroleptics because of the smallness and unbalance of the sample, but they indicate that both antipsychotics are very active and that a comprehensive rating scale such as the AMDP gives a much better differentiated clinical picture of a new drug than the total scores of short, so-called "economical" rating scales.