Nanotubes and nanowires with both elemental1,2 (carbon or silicon) and multi-element3,4,5 compositions (such as compound semiconductors or oxides), and exhibiting electronic properties ranging from metallic to semiconducting, are being extensively investigated for use in device structures designed to control electron charge6,7,8. However, another important degree of freedom—electron spin, the control of which underlies the operation of ‘spintronic’ devices9—has been much less explored. This is probably due to the relative paucity of nanometre-scale ferromagnetic building blocks10 (in which electron spins are naturally aligned) from which spin-polarized electrons can be injected. Here we describe nanotubes of vanadium oxide (VOx), formed by controllable self-assembly11, that are ferromagnetic at room temperature. The as-formed nanotubes are transformed from spin-frustrated semiconductors to ferromagnets by doping with either electrons or holes, potentially offering a route to spin control12 in nanotube-based heterostructures13.

Room-temperature ferromagnetic nanotubes controlled by electron or hole doping

Ectopic pregnancy remains a considerable cause of maternal morbidity and mortality worldwide. Currently, it is diagnosed using a combination of transvaginal ultrasound and serial serum beta-human chorionic gonadotrophin levels. Diagnosis is often delayed and these tests are time-consuming and costly, both psychologically to the patient and financially to health services. The development of a biomarker that can differentiate a tubal ectopic from an intrauterine implantation is therefore important. In the pre-genomic era, a one-by-one scientific approach has revealed over 20 candidate biomarkers that could be used as a test to diagnose ectopic pregnancy although at present their clinical utility is very limited. These biomarkers cluster into themes: markers of abnormal embryo/trophoblast growth, markers of abnormal corpus luteum function, markers of a growing pregnancy in the Fallopian tube, markers of inflammation and peritoneal irritation, and uterine markers of normal implantation. It is likely that this thematic approach will facilitate the identification of newer biomarkers using microarray technology and inform the development of investigative paradigms using multiple markers at the time of presentation.

/pdf/serum-biomarkers-of-tubal-ectopic-pregnancy-current-fkzdjoyetm.pdf

Serum biomarkers of tubal ectopic pregnancy: current candidates and future possibilities

The objective of this study was to determine the clinical presentation, treatment, and outcome of patients diagnosed with possible ectopic molar gestation registered with the Trophoblastic Disease Screening and Treatment Centre, Weston Park Hospital, Sheffield between 1986 and 2000. From the 5581 women registered, those with a diagnosis of ectopic molar pregnancy were identified from a computer database. Information regarding the relevant history of each patient and the clinical presentation, treatment, and outcomes of gestational trophoblastic disease (GTD) was determined by reviewing referral forms, case notes, and pro formas completed by the referring gynecologist. Histological review of the cases was undertaken where possible. Suspected ectopic molar gestations comprised 31/5581 (0.55%) of registrations. Known risk factors for ectopic pregnancy were identified in 79% of cases. Central histological review confirmed only six cases of GTD: three choriocarcinoma and three early complete moles. Four patients subsequently required chemotherapy. All patients are now in complete remission. We conclude that ectopic GTD is uncommon, with a UK incidence of approximately 1.5 per 1,000,000 births. Initial management is usually surgical removal of the conceptus, pathological suspicion of the diagnosis and registration with a screening center. Chemotherapy may be required and the prognosis is excellent.

https://ijgc.bmj.com/content/ijgc/14/2/366.full.pdf

The clinical presentation, treatment, and outcome of patients diagnosed with possible ectopic molar gestation.

BACKGROUND: Enhanced vascularization appears to be important for follicular selection and maturation in both spontaneous and stimulated IVF cycles. Nitric oxide, formed in vivo from L-arginine, may play a key role in follicular maturation and ovulation. METHODS: To evaluate the role of L-arginine supplementation in controlled ovarian hyperstimulation, 37 IVF patients were divided into two groups according to ovarian stimulation protocols: group I, GnRH agonist plus pure (p)FSH plus oral L-arginine (n 18); and group II, GnRH agonist plus pFSH plus placebo (n 19). Hormonal, ultrasonographic and Doppler evaluations were performed, and plasma and follicular fluid nitrite/nitrate concentrations were monitored. RESULTS: Thirty-two patients completed the study. In group I (n 16), plasma L-arginine concentrations increased from (basal) 87 12 µ mol to 279 31 µmol (P 0.002) on the day of β-HCG administration. In this group, pFSH treatment was shorter (P 0.039) than in group II (n 16). The number of the follicles ≥17 mm was lower (P 0.038) in group I than group II. The ‘good quality’ embryos were fewer in number (P 0.034) and pregnancy rate, both per patient (P 0.024) and per embryo transfer (P 0.019), was lower in group I. In the L-arginine group, an increased follicular fluid concentration of nitrite/nitrate was observed. On day 8 of the cycle, elevated plasma estradiol levels were associated with decreased blood flow resistances of perifollicular arteries. Follicular fluid concentrations of nitrite/ nitrate were inversely correlated with embryo quality (r –0.613; P 0.005) and perifollicular artery pulsatility index (r –0.609; P 0.021). CONCLUSIONS: L-Arginine supplementation may be detrimental to embryo quality and pregnancy rate during controlled ovarian hyperstimulation cycles.

/pdf/adjuvant-l-arginine-treatment-in-controlled-ovarian-2fqpzku5f9.pdf

Adjuvant L-arginine treatment in controlled ovarian hyperstimulation: a double-blind, randomized study.

Progesterone, inhibin, and hCG multiple marker strategy to differentiate viable from nonviable pregnancies.

Serum luteal phase progesterone in women undergoing frozen embryo transfer in assisted conception: a systematic review and meta-analysis.

Tubal pregnancy is now commonly managed by laparoscopic salpingostomy or systemic methotrexate. A disadvantage of such conservative management is the need for appropriate follow-up, with serial measurement of serum concentrations of human chorionic gonadotrophin (HCG), to exclude persistent ectopic pregnancy (PEP). Concentrations of inhibin A, also a placental product, are significantly increased during pregnancy and the half-life of inhibin A is significantly shorter than that of HCG. To assess the suitability of inhibin A as a marker of PEP, we studied 16 women who had undergone surgery for a tubal pregnancy, measuring HCG and inhibin during follow-up. The mean +/- SEM time taken to achieve non-pregnant concentrations of inhibin A was significantly shorter than for HCG (4.2 +/- 0.8 days versus 21.6 +/- 4.4 days respectively; P < 0.001 Wilcoxon signed rank test). However, in all women the inhibin A concentration increased rapidly after reaching a nadir, reflecting the return of ovarian function, complicating the interpretation of results. In four women inhibin A was almost undetectable preoperatively, while the corresponding HCG concentration was high. These data suggest that inhibin A will not be a useful marker for PEP but that it may provide a more accurate preoperative assessment of trophoblast viability than HCG, thereby improving management.

Evaluation of serum inhibin A as a surveillance marker after conservative management of tubal pregnancy.

https://www.fertstert.org/article/S0015-0282(98)00338-0/pdf

Different influence of incongruent follicular development on in vitro fertilization–embryo transfer and gamete intrafallopian transfer pregnancy rates

In this paper a retrospective cost comparison between laparoscopic treatment of ectopic pregnancy and conventional laparotomy under casemix funding has been performed. The total mean cost of laparoscopic treatment was $2,930 while the total mean cost of laparotomy was $4,259 per patient.

Philip Jm Lowe

Papers

Serum luteal phase progesterone in women undergoing frozen embryo transfer in assisted conception: a systematic review and meta-analysis.

Evaluation of serum inhibin A as a surveillance marker after conservative management of tubal pregnancy.

Different influence of incongruent follicular development on in vitro fertilization–embryo transfer and gamete intrafallopian transfer pregnancy rates

A casemix cost comparison of 2 treatments for ectopic pregnancy