The first example of a zirconium-oxide based metal–organic framework constructed from monocarboxylate ligands

This work reports the first example of a Zr-based MOF which is exclusively constructed from the monocarboxylate ligand formate.

Sleep Disturbances in Depression

Major depressive disorder is frequently accompanied by sleep disturbances such as insomnia or hypersomnia and polysomnographic sleep findings of increased rapid-eye-movement sleep and decreased slow wave sleep. For many patients, insomnia persists even after mood symptoms have been adequately treated. These patients have poorer outcomes than patients without sleep problems. These outcomes suggest that overlapping neural mechanisms regulate sleep and mood. Treatment of these patients can incorporate sedating antidepressants, nonbenzodiazepine γ-aminobutyric acid agonists, and cognitive behavioral therapy. Sleep restriction has been found to improve mood in depressed patients; however, the benefits typically disappear after recovery sleep.

A prostaglandin E2 receptor antagonist prevents pregnancies during a preclinical contraceptive trial with female macaques

STUDY QUESTION

Can administration of a prostaglandin (PG) E2 receptor 2 (PTGER2) antagonist prevent pregnancy in adult female monkeys by blocking periovulatory events in the follicle without altering menstrual cyclicity or general health?

SUMMARY ANSWER

This is the first study to demonstrate that a PTGER2 antagonist can serve as an effective non-hormonal contraceptive in primates.

WHAT IS KNOWN ALREADY

The requirement for PGE2 in ovulation and the release of an oocyte surrounded by expanded cumulus cells (cumulus-oocyte expansion; C-OE) was established through the generation of PTGS2 and PTGER2 null-mutant mice. A critical role for PGE2 in primate ovulation is supported by evidence that intrafollicular injection of indomethacin in rhesus monkeys suppressed follicle rupture, whereas co-injection of PGE2 with indomethacin resulted in ovulation.

STUDY DESIGN, SIZE, DURATION

First, controlled ovulation protocols were performed in adult, female rhesus monkeys to analyze the mRNA levels for genes encoding PGE2 synthesis and signaling components in the naturally selected pre-ovulatory follicle at different times after the ovulatory hCG stimulus (0, 12, 24, 36 h pre-ovulation; 36 h post-ovulation, n = 3-4/time point). Second, controlled ovarian stimulation cycles were utilized to obtain multiple cumulus-oocyte complexes (COCs) from rhesus monkeys to evaluate the role of PGE2 in C-OE in vitro (n = 3-4 animals/treatment; ≥3 COCs/animal/treatment). Third, adult cycling female cynomolgus macaques were randomly assigned (n = 10/group) to vehicle (control) or PTGER2 antagonist (BAY06) groups to perform a contraceptive trial. After the first treatment cycle, a male of proven fertility was introduced into each group and they remained housed together for the duration of the 5-month contraceptive trial that was followed by a post-treatment reversibility trial.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Quantitative real-time PCR, COC culture and expansion, immunofluorescence/confocal microscopy, enzyme immunoassay, contraceptive trial, ultrasonography, complete blood counts, serum biochemistry tests and blood lipid profiles.

MAIN RESULTS AND THE ROLE OF CHANCE

Several mRNAs encoding proteins involved in PGE2 synthesis, metabolism and signaling increase (P < 0.05) in the periovulatory follicle after administration of an ovulatory hCG bolus. PGE2 signaling through PTGER2 induces cumulus cell expansion and production of hyaluronic acid, which are critical events for fertilization. Moreover, chronic administration of a selective PTGER2 antagonist resulted in a significant (P < 0.05 versus vehicle-treated controls) contraceptive effect without altering steroid hormone patterns or menstrual cyclicity during a 5-months contraceptive trial. Fertility recovered as early as 1 month after ending treatment.

LIMITATIONS, REASONS FOR CAUTION

This is a proof-of-concept study in a non-human primate model. Further investigations are warranted to elucidate the mechanism(s) of PTGER2 antagonist action in the primate ovary. Although PTGER2 antagonist treatment did not produce any obvious undesirable effects, improvements in the mode of administration, as well as the efficacy of these compounds, are necessary to consider such a contraceptive for women.

WIDER IMPLICATIONS OF THE FINDINGS

Monitoring as well as improving the efficacy and safety of female contraceptives is an important public health activity. Even though hormonal contraceptives are effective for women, concerns remain regarding their side-effects and long-term use because of the widespread actions of such steroidal products in many tissues. Moreover, some women cannot take hormones for medical reasons. Thus, development of non-hormonal contraceptives for women is warranted.

STUDY FUNDING/COMPETING INTEREST(S)

Supported by Bayer HealthCare Pharmaceuticals, The Eunice Kennedy Shriver NICHD Contraceptive Development and Research Center (U54 HD055744), NIH Office of the Director (Oregon National Primate Research Center P51 OD011092), and a Lalor Foundation Postdoctoral Basic Research Fellowship (MCP). The use of the Leica confocal was supported by grant number S10RR024585. Some of the authors (N.B., A.R., K.-H.F., U.F., B.B. and B.L.) are employees of Bayer Healthcare Pharma.

Multifunctional MOFs through CO2fixation: a metamagnetic kagome lattice with uniaxial zero thermal expansion and reversible guest sorption

The properties of atmospheric CO₂fixation, metamagnetism, reversible guest adsorption and zero thermal expansion have been combined in a single robust MOF, [Cu₃(bpac)₃(CO₃)₂](ClO₄)₂·H₂O (1·H₂O).

Magnetic, electrochemical and optical properties of a sulfate-bridged Co(ii) imidazole dimer

The electrochemical, optical and magnetic properties of a sulfate-bridged high spin Co(ii) dimer, [Co₂(DMIM)₄(μ₂-O²,O,O′-SO₄)₂]·2MeCN are reported. Antiferromagnetic coupling across the μ₂-(O²-sulfato) bridging mode has been identified with J = −28 cm⁻¹.

Magnetic and Electronic Properties of Three New Hetero-Bimetallic Coordination Frameworks [Ru2(O2CR)4][Au(CN)2] (R = Benzoic Acid, Furan-2-carboxylate, or Thiophen-2-carboxylate)

The crystal structures and magnetic and electronic properties of three new hetero-bimetallic coordination frameworks, [Ru2(O2CR)4][Au(CN)2] (R = phenyl (1(Ph)), 2-furan (1(Furan)), and 2-thiophene (1(Thio)), have been characterised. Through variation of the functionalised carboxylate group, both the one-dimensional chain structure and properties of the frameworks have been systematically modulated. The magnetic behaviour for each framework has been modelled with a zero-field splitting model and the presence of weak inter-dimer coupling was assessed.

The effect of temperature elevation on cryopreserved mesenchymal stem cells

BACKGROUND

Cryopreservation is of particular importance in stem cell research and regenerative medicine as it permits long term stabilisation of biological cells. Cells retain their regenerative capacity after years of storage at cryogenic temperatures. However, elevation of temperature may occur due to variety of reasons, for example in the event of equipment malfunction or during delays in transportation. To date, a limited amount research has been carried out to examine the effects of temperature elevation on stem cell survival during cryopreservation.

METHODS

Mesenchymal Stem Cells (MSCs) obtained from 8-12 week Sprague Dawley male rats were cryopreserved according to the standard procedures. Under experimental conditions, cryopreserved specimens were exposed to elevated temperatures ranging from -20 C to 37 C and cellular membrane integrity assessed via trypan-blue exclusion at various time points.

RESULTS

An approximating model of multiple regression was fitted to the experimental data and optimisation of model parameters was carried out. This model provides an approximation of cell viability in response to elevated temperature conditions.

DISCUSSION

The results demonstrate that elevation of temperature has a dramatic effect, even over short periods of time, on the viability of cryopreserved specimens. The model presented here could be used to predict the damage suffered by a specimen due to exposure to elevated temperature over a defined period of time.

Age- and gender-specific TSH reference intervals in people with no obvious thyroid disease in Tayside, Scotland: the Thyroid Epidemiology, Audit, and Research Study (TEARS)

OBJECTIVE

The aim of the study was to examine the association of tested TSH with age, gender, and diabetes in a large population-based cohort without evidence of thyroid disease.

DESIGN

Record-linkage technology was used retrospectively to identify people without evidence of thyroid disease in the general population of Tayside, Scotland, from July 1, 2003, to December 31, 2009.

COHORT

All Tayside residents who had thyroid function tests performed were identified. Using a unique patient identifier, data linkage enabled a cohort without thyroid disease to be identified by excluding anyone with thyroid or antithyroid prescription, thyroid-related admission or surgery, treatment with radioactive iodine and/or positive thyroid antibodies. Cases below 18 years of age were also excluded.

OUTCOME MEASURES

We measured TSH distribution among different age groups and by gender.

RESULTS

We identified the latest TSH measurements in 153127 people from the reference population after applying the exclusion criteria. There was a significant increase in median TSH (1.58 mU/L at 31-40 y to 1.86 mU/L at >90 y; P < .001) and 97.5th centile TSH (3.98 to 5.94 mU/L, respectively) with increasing age. The 2.5th centile decreased with age (0.51 to 0.31 mU/L). Patients with diabetes had marginally higher TSH concentration (1.80 vs 1.70 mU/L; P < .001).

CONCLUSION

The use of these age-specific reference intervals for TSH, especially in those over 70 years old, would result in the reclassification of many TSH results from "abnormal" to "normal" (within the 95th centile reference interval) and avoid unnecessary treatment.

Obesity-induced insulin resistance in human skeletal muscle is characterised by defective activation of p42/p44 MAP kinase

Insulin resistance (IR), an impaired cellular, tissue and whole body response to insulin, is a major pathophysiological defect of type 2 diabetes mellitus. Although IR is closely associated with obesity, the identity of the molecular defect(s) underlying obesity-induced IR in skeletal muscle remains controversial; reduced post-receptor signalling of the insulin receptor substrate 1 (IRS1) adaptor protein and downstream effectors such as protein kinase B (PKB) have previously been implicated. We examined expression and/or activation of a number of components of the insulin-signalling cascade in skeletal muscle of 22 healthy young men (with body mass index (BMI) range, 20-37 kg/m(2)). Whole body insulin sensitivity (M value) and body composition was determined by the hyperinsulinaemic (40 mU. min(-1).m(-2).), euglycaemic clamp and by dual energy X-ray absorptiometry (DEXA) respectively. Skeletal muscle (vastus lateralis) biopsies were taken before and after one hour of hyperinsulinaemia and the muscle insulin signalling proteins examined by western blot and immunoprecipitation assay. There was a strong inverse relationship between M-value and BMI. The most striking abnormality was significantly reduced insulin-induced activation of p42/44 MAP kinase, measured by specific assay, in the volunteers with poor insulin sensitivity. However, there was no relationship between individuals' BMI or M-value and protein expression/phosphorylation of IRS1, PKB, or p42/44 MAP kinase protein, under basal or hyperinsulinaemic conditions. In the few individuals with poor insulin sensitivity but preserved p42/44 MAP kinase activation, other signalling defects were evident. These findings implicate defective p42/44 MAP kinase signalling as a potential contributor to obesity-related IR in a non-diabetic population, although clearly multiple signalling defects underlie obesity associated IR.

Impact of student choice on academic performance: cross-sectional and longitudinal observations of a student cohort

BACKGROUND

Student choice plays a prominent role in the undergraduate curriculum in many contemporary medical schools. A key unanswered question relates to its impact on academic performance.

METHODS

We studied 301 students who were in years 2 and 3 of their medical studies in 2005/06. We investigated the relationship between SSC grade and allocated preference. Separately, we examined the impact of 'self-proposing' (students designing and completing their own SSC) on academic performance in other, standard-set, summative assessments throughout the curriculum. The chi-squared test was used to compare academic performance in SSC according to allocated preference. Generalised estimating equations were used to investigate the effect of self-proposing on performance in standard-set examinations.

RESULTS

(1) Performance in staff-designed SSC was not related to allocated preference. (2) Performance in year 1 main examination was one of the key predictors of performance in written and OSCE examinations in years 2, 3 and 4 (p<0.001). (3) The higher the score in the year 1 examination, the more likely a student was to self-propose in subsequent years (OR [CI] 1.07 [1.03-1.11], p<0.001). (4) Academic performance of students who self-proposed at least once in years 2 and/or 3 varied according to gender and year of course.

CONCLUSION

In this study, no association was observed between allocated preference and SSC grade. The effect of self-proposing on academic performance in standard-set examinations was small. Our findings suggest instead that academically brighter students are more likely to design their own modules. Although student choice may have educational benefits, this report does not provide convincing evidence that it improves academic performance.