Gestation as mothering

Some commentators maintain that gestational surrogates are not ‘mothers’ in a way capable of grounding a claim to motherhood. These commentators find that the practices that constitute motherhood do not extend to gestational surrogates. We argue that gestational surrogates should be construed as mothers of the children they bear, even if they fully intend to surrender those children at birth to the care of others. These women stand in a certain relationship to the expected children: they live in changed moral circumstances by reason of their pregnancy, and they engage in the practices said to define motherhood in the post-birth context. By contrast, ovum donors and embryo donors are not similarly ‘mothers’ because they do not find themselves involved in these circumstances. Not all women involved in three-parent in vitro fertilization qualify as mothers either. Given this analysis of mothering, we note that transmen who gestate children are engaged in mothering activity even if they otherwise function as a father to those children. By itself, this defence of the maternity of gestational surrogates does not confer moral title to the children they bear; gestation would not by itself override the contractual arrangements gestational surrogates have made regarding the disposition of their children. This interpretation of gestational surrogates as mothers does, however, undercut cultural understandings of these women as mere ‘vessels’, devoid of entitlement to respect as persons and parents. We also consider the meaning of mothering for ‘brain-dead’ women kept alive to give birth and for the prospect of extracorporeal gestation.     

Hypoxia stimulates osteoclast formation from human peripheral blood

Active pathological bone destruction in humans often occurs in locations where oxygen tension (pO₂) is likely to be low, for example, at the sites of tumours, inflammation, infections and fractures, or the poorly vascularized yellow fatty marrow of the elderly. We examined the effect of pO₂ on formation of osteoclasts, the cells responsible for bone resorption, in 14‐day cultures of normal human peripheral blood mononuclear cells (hPBMCs) on ivory discs. Hypoxia (1–2% O₂) caused threefold increases in the number of osteoclasts formed, compared with 20% O₂. Hypoxia also caused a twofold increase in the number of nuclei per osteoclast, leading to stimulations of resorption pit formation of up to 10‐fold. Exposure to hypoxia led to stabilization of the hypoxia‐inducible factors, HIF1α and HIF2α, and upregulation of vascular endothelial growth factor and interleukin‐6 expression by hPBMCs. These findings help explain why extravasation of mononuclear precursors into relatively O₂‐deficient bone microenvironments could result in osteoclast formation and suggest a new mechanism for the bone loss associated with the pathophysiological conditions where hypoxia commonly occurs. Copyright © 2010 John Wiley & Sons, Ltd.     

Perceived and Physiological Indicators of Relaxation: As Different as Mozart and Alice in Chains

The effects of listening to different types of music on perceived and physiological indicators of relaxation were evaluated. Fifty-six undergraduate students, 24 males and 32 females, mean age of 21, were randomly assigned to listen to classical, hard rock, self-selected relaxing music, or no music. Participants' relaxation level, skin temperature, muscle tension and heart rate were evaluated before and after exposure to a music condition. Analyses of variance using baseline measures as covariates indicated that skin temperature decreased for all conditions (p = 0.001) and the classical, self-selected relaxing music and no music groups reported significant increases in feelings of relaxation (p = 0.004). These results partially support the hypothesis that classical and self-selected relaxing music can increase perceptions of relaxation to a greater degree than listening to hard rock music. However, no differences were found between different types of music on physiological indicators of arousal. Implications for using music to reduce stress were discussed.     

ESEEM and Mössbauer studies of the ferriheme model compound bis(3-aminopyrazole)tetraphenylporphyrinatoiron(III) chloride, [TPPFe(NH2PzH)2]Cl

A model heme complex, bis(3-aminopyrazole)tetraphenylporphinatoiron(III) chloride, [TPPFe (NH₂PzH)₂]Cl, for which the EPR g-values lead to a rhombicity V/Δ=1.2 if g _zz is the largest g-value, have been investigated by electron spin echo envelope modulation (ESEEM) and Mössbauer spectroscopies. The ESEEM studies focus on the proton sum frequency peaks at near twice the proton Larmor frequency. Analysis of the distant proton peak (mainly due to the pyrrole-H) at exactly twice the proton Larmor frequency shows conclusively that g _zz is aligned along the normal to the porphyrin plane, and thus the electron configuration is (d _xy )²(d _xz ,d _yz )³, with g _zz >g _yy >g _xx . This system is thus another violation to Taylor's "proper axis system" rule. The near proton (the α-H and N-H of the axial ligands) peaks provide distance information for those protons from the metal. Magnetic Mössbauer studies of the same complex confirm the (d _xy )²(d _xz ,d _yz )³ ground state and indicate that, as is the case for cytochrome P450_cam, A _xx is the largest magnitude A-value, and is negative in sign. Other low-spin iron(III) porphyrinates also have A _xx of negative sign, but usually the magnitude is only about half that of A _zz , which is always positive in sign.     

Determination of platinum in rat dorsal root ganglion using ICP-MS

This study evaluated the performance of inductively coupled plasma mass spectrometry for the determination of platinum (Pt) in rat dorsal root ganglion. The method detection limit was found to be 0.008 ng/mL of Pt, which corresponds to 4 pg of Pt per milligram of ganglia. The standard deviations in the tissue matrix were 5.7% or better and minimum matrix effect was observed. Compared to indium, the use of iridium or a combination of iridium and bismuth as internal standard(s) provided more accurate measurement. The Pt in the tissue digestate was stable for a minimum of 46 d at levels above 0.05 ng/mL. Flow injection analysis using undiluted digestates resulted in approximately 20% signal enhancement. Internal standard correction was necessary to obtain accurate results. The method was used in initial studies in which rats were dosed with cisplatin and has shown that Pt accumulates and persists in dorsal rat ganglion following treatment. Paper presented at the Pittsburgh Conference, Atlanta, GA, March 1997     

Potentiation of myoblast transplantation by host muscle irradiation is dependent on the rate of radiation delivery

Transplantation of muscle precursor cells (mpc) has been suggested as a treatment for myopathies, such as Duchenne muscular dystrophy. Irradiation of skeletal muscle with 16-20 Gy prevents muscle regeneration and also augments muscle formation from implanted muscle precursor cells (mpc). However, when mdx nu/nu mouse muscles are preirradiated at 0.73 Gy/min rather than at 1.29 Gy/min prior to their injection with normal mpc, significantly more muscle fibres of donor origin are formed. This suggests that the rate at which irradiation is delivered has a physiological effect on the muscle. Although it would not be feasible to irradiate a patient's muscles prior to mpc implantation, once the factor(s) which are altered in irradiated muscle have been identified, it might be possible to use these to increase the success of myoblast transplantation.