Vaccine microarray patch self-administration: An innovative approach to improve pandemic and routine vaccination rates

The high-density microprojection array patch (HD-MAP) is a novel vaccine delivery system with potential for self-administered vaccination. HD-MAPs provide an alternative to needle and syringe (N&S) vaccination. Additional advantages could include reduced cold-chain requirements, reduced vaccine dose, reduced vaccine wastage, an alternative for needle phobic patients and elimination of needlestick injuries. The drivers and potential benefits of vaccination by self-administering HD-MAPs are high patient acceptance and preference, higher vaccination rates, speed of roll-out, cost-savings, and reduced sharps and environmental waste. The HD-MAP presents a unique approach in pandemic preparedness and routine vaccination of adults. It could alleviate strain on the healthcare workforce and allows vaccine administration by minimally-trained workers, guardian or subjects themselves. Self-vaccination using HD-MAPs could occur in vaccination hubs with supervision, at home after purchasing at the pharmacy, or direct distribution to in-home settings. As a result, it has the potential to increase vaccine coverage and expand the reach of vaccines, while also reducing labor costs associated with vaccination. Key challenges remain around shifting the paradigm from medical professionals administrating vaccines using N&S to a future of self-administration using HD-MAPs. Greater awareness of HD-MAP technology and improving our understanding of the implementation processes required for adopting this technology, are critical factors underpinning HD-MAP uptake by the public.

Powder plasma spheroidization treatment and the characterization of microstructure and mechanical properties of SS 316L powder and L-PBF builds

A plasma spheroidization treatment was applied to stock stainless steel 316L powder for additive manufacturing. The normal and treated powders were compared both in the powder state as well as in the resulting laser powder bed fusion (L-PBF) builds. The plasma spheroidization process slightly increased treated powder aspect ratio and sphericity and shifted the size distribution to larger diameters relative to the normal powder. The normal powder was austenitic in nature whereas the plasma spheroidization process introduced a small fraction (∼3.5 vol %) of ferrite in the treated powder. Ferrite in the powder was not retained in the printed samples and was not shown to negatively affect the build quality. Porosity areal fraction was generally smaller in the treated powder builds. The normal powder builds had a 6% higher yield strength than treated, however the scatter was significantly larger in the 45° and horizontal orientations compared to the treated powder builds.

Evaluation of the self-administration potential of high-density microarray patches to human skin: A preliminary study

The high-density microneedle array patch (HD-MAP) is a novel vaccine delivery system with potential for self-administered vaccination. In this study, Vaxxas HD-MAPs were applied by both a trained user and self-administered with application sites compared to determine the response of skin and the level of engagement of the HD-MAP with human skin. Twenty healthy participants were enrolled, and the response of skin including erythema was observed at all application sites and no difference was found between trained user or self-administered applications. The majority of participants (70%) preferred the deltoid upper arm application site for applying HD-MAPs. Fluorescent dermatoscope images confirmed HD-MAPs engaged the skin surface and scanning electron microscopy (SEM) image analysis exhibited similar delivery characteristics for the upper arm and forearm sites when applied by either a trained user or self-administered. This study showed that noninvasive methods including dermatoscopy and SEM image analysis were able to estimate the engagement of HD-MAPs with human skin. HD-MAP self-vaccination technology has a unique proposition in pandemic preparedness by alleviating the need for health-care workers to administer vaccines, however greater awareness and understanding of the potential of this technology is required.

2'-5'-Oligoadenylate synthetase-like protein inhibits intracellular M. tuberculosis replication and promotes proinflammatory cytokine secretion

Host cytoplasmic surveillance pathways are known to elicit type I interferon (IFN) responses which are crucial to antimicrobial defense mechanisms. Oligoadenylate synthetase-like (OASL) protein has been extensively characterized as a part of the anti-viral mechanism, however a number of transcriptomic studies reveal its upregulation in response to infection with a wide variety of intracellular bacterial pathogens. To date, there is no evidence documenting the role (if any) of OASL during mycobacterium tuberculosis infection. Using two pathogenic strains differing in virulence only, as well as the non-pathogenic M. bovis BCG strain, we observed that pathogenicity and virulence strongly induced OASL expression after 24 h of infection. Further, we observed that OASL knock down led to a significant increase in M. tb CFU counts 96 h post-infection in comparison to the respective controls. Luminex revealed that OASL silencing significantly decreased IL-1β, TNF-α and MCP-1 secretion in THP-1 cells and had no effect on IL-10 secretion. We therefore postulate that OASL regulates pro-inflammatory mediators such as cytokines and chemokines which suppress intracellular mycobacterial growth and survival.

P1760Incidence and effects of stroke, MI and bleeding on mortality among patients with ACS undergoing PCI: a comparative analysis from the PROMETHEUS registry

Background

Stroke represents a potentially calamitous complication among patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) even though its rates are relatively low. Data on the distribution of stroke occurrence over time and its overlap with myocardial infarction (MI) and bleeding after PCI is scarce.

Purpose

We sought to compare the occurrence and impacts of stroke, MI and bleeding on subsequent mortality in ACS patients undergoing PCI in contemporary clinical practice.

Methods

A total of 19,914 ACS patients who underwent PCI in the PROMETHEUS multi-center observational study were analyzed. We calculated the cumulative stroke incidence at 30 days and 1 year using Kaplan Meier (KM) method. We also compared the distribution of stroke, myocardial infarction (MI) and bleeding across time and evaluated the overlap between their occurrences. Predictors of 1 year stroke occurrence were identified through multivariable Cox-regression and stroke, MI and bleeding were entered as time-updated covariates to estimate their individual effects on subsequent mortality.

Results

Of the total number of patients, 244 patients (1.5%) had a stroke within 1 year. 48 of these patients also experienced an MI while another 48 patients experienced a bleeding event. Furthermore, 14 of these overlapping patients experienced a stroke, MI and bleeding event, all within the 1-year follow-up. Patients who sustained a stroke were more likely to have a prior history of cerebrovascular disease, peripheral artery disease, MI and heart failure compared to those who did not have a stroke. Mortality risk was significantly higher among those with stroke versus those without stroke (adjusted HR 4.84, p<0.0001). However, the association attenuated over time with a much larger effect in the first 30 days of its occurrence (adjusted HR 17.7, p<0.0001) versus beyond 30 days (adjusted HR 1.22; 95% CI: 0.6–2.46, p=0.58). Although the effects of MI and bleeding on subsequent mortality within 30 days of occurrence were significantly lower than stroke (adjusted HR 6.22, p<0.0001; adjusted HR 7.30, p<0.0001, respectively), their effects were more sustained on mortality beyond 30 days (adjusted HR 2.89, p<0.0001; adjusted HR 3.05, p<0.0001, respectively).

Conclusion

When compared with MI and bleeding, stroke had a substantially stronger impact on mortality that attenuated rapidly over time among ACS patients undergoing PCI. Optimization of modifiable risk factors and medication adherence are essential parts of management of stroke following PCI for ACS.

Generation and characterization of thiol-deficient Mycobacterium tuberculosis mutants

Mycothiol (MSH) and ergothioneine (ERG) are thiols able to compensate for each other to protect mycobacteria against oxidative stress. Gamma-glutamylcysteine (GGC), another thiol and an intermediate in ERG biosynthesis has detoxification abilities. Five enzymes are involved in ERG biosynthesis, namely EgtA, EgtB, EgtC, EgtD and EgtE. The role of these enzymes in the production of ERG had been unclear. On the other hand, the enzyme MshA is known to be essential for MSH biosynthesis. In this manuscript, we describe the raw data of the generation and characterization of Mycobacterium tuberculosis (M.tb) mutants harbouring a deletion of the gene coding for each of these enzymes, and the raw data of the phenotypic characterization of the obtained thiol-deficient M.tb mutants. High throughput screening (HTS) of off-patent drugs and natural compounds revealed few compounds that displayed a higher activity against the thiol-deficient mutants relative to the wild-type strain. The mode of action of these drugs was further investigated. Raw data displaying these results are described here.

The functional interplay of low molecular weight thiols in Mycobacterium tuberculosis

BACKGROUND

Three low molecular weight thiols are synthesized by Mycobacterium tuberculosis (M.tb), namely ergothioneine (ERG), mycothiol (MSH) and gamma-glutamylcysteine (GGC). They are able to counteract reactive oxygen species (ROS) and/or reactive nitrogen species (RNS). In addition, the production of ERG is elevated in the MSH-deficient M.tb mutant, while the production of MSH is elevated in the ERG-deficient mutants. Furthermore, the production of GGC is elevated in the MSH-deficient mutant and the ERG-deficient mutants. The propensity of one thiol to be elevated in the absence of the other prompted further investigations into their interplay in M.tb.

METHODS

To achieve that, we generated two M.tb mutants that are unable to produce ERG nor MSH but are able to produce a moderate (ΔegtD-mshA) or significantly high (ΔegtB-mshA) amount of GGC relative to the wild-type strain. In addition, we generated an M.tb mutant that is unable to produce GGC nor MSH but is able to produce a significantly low level of ERG (ΔegtA-mshA) relative to the wild-type strain. The susceptibilities of these mutants to various in vitro and ex vivo stress conditions were investigated and compared.

RESULTS

The ΔegtA-mshA mutant was the most susceptible to cellular stress relative to its parent single mutant strains (ΔegtA and ∆mshA) and the other double mutants. In addition, it displayed a growth-defect in vitro, in mouse and human macrophages suggesting; that the complete inhibition of ERG, MSH and GGC biosynthesis is deleterious for the growth of M.tb.

CONCLUSIONS

This study indicates that ERG, MSH and GGC are able to compensate for each other to maximize the protection and ensure the fitness of M.tb. This study therefore suggests that the most effective strategy to target thiol biosynthesis for anti-tuberculosis drug development would be the simultaneous inhibition of the biosynthesis of ERG, MSH and GGC.

Realization of a Λ System with Metastable States of a Capacitively Shunted Fluxonium

We realize a Λ system in a superconducting circuit, with metastable states exhibiting lifetimes up to 8 ms. We exponentially suppress the tunneling matrix elements involved in spontaneous energy relaxation by creating a "heavy" fluxonium, realized by adding a capacitive shunt to the original circuit design. The device allows for both cavity-assisted and direct fluorescent readouts, as well as state preparation schemes akin to optical pumping. Since direct transitions between the metastable states are strongly suppressed, we utilize Raman transitions for coherent manipulation of the states.

Differential inhibition of adenylylated and deadenylylated forms of M. tuberculosis glutamine synthetase as a drug discovery platform

Glutamine synthetase is a ubiquitous central enzyme in nitrogen metabolism that is controlled by up to four regulatory mechanisms, including adenylylation of some or all of the twelve subunits by adenylyl transferase. It is considered a potential therapeutic target for the treatment of tuberculosis, being essential for the growth of Mycobacterium tuberculosis, and is found extracellularly only in the pathogenic Mycobacterium strains. Human glutamine synthetase is not regulated by the adenylylation mechanism, so the adenylylated form of bacterial glutamine synthetase is of particular interest. Previously published reports show that, when M. tuberculosis glutamine synthetase is expressed in Escherichia coli, the E. coli adenylyl transferase does not optimally adenylylate the M. tuberculosis glutamine synthetase. Here, we demonstrate the production of soluble adenylylated M. tuberulosis glutamine synthetase in E. coli by the co-expression of M. tuberculosis glutamine synthetase and M. tuberculosis adenylyl transferase. The differential inhibition of adenylylated M. tuberulosis glutamine synthetase and deadenylylated M. tuberulosis glutamine synthetase by ATP based scaffold inhibitors are reported. Compounds selected on the basis of their enzyme inhibition were also shown to inhibit M. tuberculosis in the BACTEC 460TB™ assay as well as the intracellular inhibition of M. tuberculosis in a mouse bone-marrow derived macrophage assay.

PerFlexMEA: a thin microporous microelectrode array for in vitro cardiac electrophysiological studies on hetero-cellular bilayers with controlled gap junction communication

The new microelectrode array device presented is called PerFlexMEA and it enables controlled coupling between myocytes and nonmyocytes used in cardiovascular conduction studies. The device consists of an 8 μm thin parylene microporous membrane with a 4 × 5 microelectrode array patterned on one side. Myocytes and nonmyocytes can be plated on either side of the parylene membrane to create a tissue bilayer. The 3-3.5 μm diameter pores allow inter-layer dye and electrical coupling without transmembrane cell migration. Cell migration was found to vary with cell-type and micropore diameter. Pore density can be varied based on desired coupling ratio. The flexible parylene membrane is packaged between two rigid thermoplastic layers, such that the microelectrode array region is exposed, while the rest of the device remains insulated. The packaged PerFlexMEA fits in a 60 mm culture dish. Recording experiments are performed by simply plugging it into a commercially available multielectrode amplifier system. Recorded signals were processed and analysed using scripts generated in MATLAB. Our experimental results provide evidence of the reliability of this device, as conduction velocity was observed to decrease after inducing lateral hetero-cellular controlled coupling between myocytes and HeLa cells expressing connexin 43.

Omitting pre-operative coagulation screening tests in hip fracture patients: stopping the financial cascade?

BACKGROUND

Coagulation screening continues as a standard of care in many hip fracture pathways despite the 2011 guidelines from the Association of Anaesthetists of Great Britain and Ireland (AAGBI) which recommend that such screening be performed only if clinically indicated. This study aims to evaluate the use of pre-operative coagulation screening and explore its financial impact.

METHODS

Prospective data was collected in accordance with the "Standardised Audit of Hip Fractures in Europe" (SAHFE) protocol. All patients admitted to our hospital with hip fractures during a 12-month period from November 2011 to November 2012 were analysed. Data including coagulation results and the use of vitamin K or blood products were collected retrospectively from the hospital computer system. Patient subgroup analysis was performed for intraoperative blood loss, post-operative blood units transfused, haematoma formation and gastrointestinal haemorrhage.

RESULTS

814 hip fractures were analysed. 91.4% (n=744) had coagulation tests performed and 22.0% (n=164) had an abnormal result. Of these, 55 patients were taking warfarin leaving 109 patients who had abnormal results and were not taking warfarin. When this group (n=109) was compared to those who had normal test results (n=580) and to all other patients (n=705) there was no difference in intraoperative blood loss (p=0.79, 0.78), postoperative transfusion (p=0.38, 0.30), postoperative haematoma formation (p=0.79, 1.00), or gastrointestinal haemorrhage (p=0.45, 1.00), respectively. In those who were not taking warfarin, but had abnormal results, none had treatment to reverse their coagulopathy with either vitamin K or blood products. By omitting pre-operative coagulation tests in patients who are not taking warfarin, we estimate a financial saving of between £66,500 and £432,250 per annum.

CONCLUSIONS

This study supports the hypothesis that routine pre-operative coagulation screening is unnecessary in hip fracture patients unless they take warfarin or have a known coagulopathy. Moreover, its omission represents significant cost-saving potential.

Maternal supportive and interfering control as predictors of adaptive and social development in children with and without developmental delays

BACKGROUND

Parents of children with developmental delays (DD) have been found to use more controlling behaviour with their children than parents of children with typical development (TD). While controlling behaviour is related to poorer developmental outcomes in TD children, there is little research on how it predicts outcomes in DD children. Furthermore, existing research tends to use inconsistent or non-specific definitions of controlling behaviour, often combining parent control which follows the child's goal (e.g. supportive direction) and that which interferes with the child's goal (e.g. interference).

METHODS

Participants were 200 mother-child dyads observed at child age 3, with follow-up assessments of adaptive behaviour and social skills administered at child ages 5 and 6, respectively. We coded the frequency of both types of controlling behaviour based on mothers' interactions with their children with TD (n = 113) or DD (n = 87) at age 3.

RESULTS

Mothers in the DD group used more interfering but not more supportive directive acts compared to mothers in the TD group. Adaptive behaviour was assessed at child age 5 and social skills were assessed at age 6. Higher frequency of supportive directive acts predicted better adaptive functioning for the TD group and better social skills for the DD group. Higher frequency of interfering acts predicted lower adaptive and social skills for children with DD but not with TD.

CONCLUSIONS

Results are discussed in terms of the differential developmental needs of children with and without DD as well as implications for early intervention.

Septic arthritis in the era of immunosuppressive treatments

Immunosuppressants have been the mainstay of treatment for certain inflammatory joint conditions for many years. Developments in this field, namely biological treatments, have led to a change in the classical presentation of acute bone, joint and soft tissue infections. The normal findings of severe pain and tenderness on examination may be absent or simply mimic a typical exacerbation of the chronic joint condition. A minimally raised white cell count and elevated C-reactive protein in the absence of systemic signs of infection may be interpreted as further evidence for the diagnosis of an exacerbation of inflammatory arthritis. We present a unique case of recurrent polyarticular septic arthritis in a patient treated with immunosuppression for refractory rheumatoid arthritis. We hope this article will enable doctors to appreciate and recognise the changing face of septic arthritis in the modern era of immunosuppressant treatments.

Diversity of movements by individual anadromous coastal cutthroat trout Oncorhynchus clarkii clarkii

Wild, downstream-migrating cutthroat trout, Oncorhynchus clarkii clarkii, smolts and adults were captured at a weir in Big Beef Creek, Hood Canal, Washington, surgically implanted with acoustic tags and tracked to identify spring and summer movements using stationary receivers in order to test the assumption that the species moves little while in marine waters. Overall, 93-96% migrated from the stream into the east side of the long narrow fjord, where they dispersed north and south along the shoreline. Most O. c. clarkii were detected nearshore within 10 km of the release site, with declining detection rates to 77 km. Over one-third (36%) crossed c. 2-4 km of deep water to the other side but only one O. c. clarkii left the Hood Canal basin. Movements and behaviour patterns did not differ between smolts and adults but cluster analysis revealed two modes of distribution, here categorized as residents and migrants. Within these categories of overall distribution, a range of finer-scale behaviour patterns was observed, including sedentary individuals, daily moving between proximate sites and more continuous long-distance travel. Diel movement patterns varied markedly among individuals but overall activity increased near dawn, peaked around mid-day and declined but continued at night. These patterns contrast with sympatric and closely related steelhead trout, Oncorhynchus mykiss, providing new insights into the diversity of salmonid behaviour.

Enriching the captive elephant population genetic pool through artificial insemination with frozen-thawed semen collected in the wild

The first successful AI in an elephant was reported in 1998, using fresh semen. Since then almost 40 calves have been produced through AI in both Asian and African elephants worldwide. Following these successes, with the objective of enriching the captive population with genetic material from the wild, we evaluated the possibility of using frozen-thawed semen collected from wild bulls for AI in captivity. Semen, collected from a 36-yr-old wild African savanna elephant (Loxodonta africana) in South Africa was frozen using the directional freezing technique. This frozen-thawed semen was used for four inseminations over two consecutive days, two before and two after ovulation, in a 26-yr-old female African savanna elephant in Austria. Insemination dose of 1200 × 10(6) cells per AI with 61% motility resulted in pregnancy, which was confirmed through ultrasound examination 75, 110 and 141 days after the AI procedure. This represents the first successful AI using wild bull frozen-thawed semen in elephants. The incorporation of AI with frozen-thawed semen into the assisted reproduction toolbox opens the way to preserve and transport semen between distant individuals in captivity or, as was done in this study, between wild and captive populations, without the need to transport stressed or potentially disease-carrying animals or to remove animals from the wild. In addition, cryopreserved spermatozoa, in combination with AI, are useful methods to extend the reproductive lifespan of individuals beyond their biological lifespan and an important tool for genetic diversity management and phenotype selection in these endangered mammals.

In vitro efficacy of bismuth thiols against biofilms formed by bacteria isolated from human chronic wounds

AIMS

The purpose of this study was to evaluate the antimicrobial efficacy of thirteen bismuth thiol preparations for bactericidal activity against established biofilms formed by two bacteria isolated from human chronic wounds.

METHODS

Single species biofilms of a Pseudomonas aeruginosa or a methicillin-resistant Staphylococcus aureus were grown in either colony biofilm or drip-flow reactors systems. Biofilms were challenged with bismuth thiols, antibiotics or silver sulfadiazine, and log reductions were determined by plating for colony formation.

CONCLUSIONS

Antibiotics were ineffective or inconsistent against biofilms of both bacterial species tested. None of the antibiotics tested were able to achieve >2 log reductions in both biofilm models. The 13 different bismuth thiols tested in this investigation achieved widely varying degrees of killing, even against the same micro-organism in the same biofilm model. For each micro-organism, the best bismuth thiol easily outperformed the best conventional antibiotic. Against P. aeruginosa biofilms, bismuth-2,3-dimercaptopropanol (BisBAL) at 40-80 μg ml⁻¹ achieved > 7·7 mean log reduction for the two biofilm models. Against MRSA biofilms, bismuth-1,3-propanedithiol/bismuth-2-mercaptopyridine N-oxide (BisBDT/PYR) achieved a 4·9 log reduction.

SIGNIFICANCE AND IMPACT OF THE STUDY

Bismuth thiols are effective antimicrobial agents against biofilms formed by wound bacteria and merit further development as topical antiseptics for the suppression of biofilms in chronic wounds.

Parents' emotion expression as a predictor of child's social competence: children with or without intellectual disability

BACKGROUND

Parents' expression of positive emotion towards children who are typically developing (TD) is generally associated with better social development. However, the association between parents' negative emotion expression and social development can be positive or negative depending upon a number of factors, including the child's emotion regulation abilities. Given the lower emotion regulation capabilities of children with intellectual disability (ID), we hypothesised that parents' negative emotion expression would be associated with lower social development in children with ID compared to those with TD.

METHODS

Participants were 180 families of children with or without ID enrolled in a longitudinal study. Parents' positive and negative affect were coded live from naturalistic home interactions at child ages 5-8 years, and child's social skills were measured by using mother report at child ages 6-9 years. We examined mothers' and fathers' emotion expression as a time-varying predictor of social skills across ages 5-9 years.

RESULTS

Mothers, but not fathers, expressed less positive affect and more negative affect with ID group children. Parents' positive affect expression was related to social skills only for TD children, with mothers' positive affect predicting higher social skills. Contrary to expectations, fathers' positive affect predicted lower social skills. Parents' negative affect predicted significantly lower social skills for children with ID than for children with TD.

CONCLUSIONS

Findings support the theory that low to moderate levels of negative expression may be less beneficial or detrimental for children with ID compared to children with TD. Implications for further research and intervention are discussed.

Transposition of the maize controlling element "Activator" in tobacco

Transposition of the maize autonomous controlling element Activator (Ac) and a nonautonomous derivative, Dissociation (Ds), was investigated in tobacco cells. Tobacco protoplasts were transformed with Ti-plasmid vectors that contained Ac or Ds flanked by short maize wx gene sequences. The structures of the elements and surrounding wx and T-DNA sequences were investigated in nine Ac and five Ds tobacco transformants by digestion with restriction enzymes, Southern blotting, and hybridization using specific probes. In four of the nine Ac transformed lines, Ac had excised from its original position in the T-DNA and inserted at new sites in the tobacco genome. Ds did not excise from its original T-DNA position in any of the transformants examined. Two Ac fragments and cellular flanking sequences were cloned from a line of tobacco in which Ac had transposed. Fragments, comprised of sequences flanking the newly integrated Ac elements, were used as hybridization probes to normal tobacco DNA and to the tobacco DNA from which they were isolated. The Ac copies were integrated into repetitive tobacco DNA sequences. Two tobacco fragments containing empty Wx donor sites were cloned from the DNA of the same Ac transformant and sequenced. Both sequences are among the types of excision products observed to result from Ac-catalyzed excision events in maize. Our results indicate that the maize controlling element Ac is capable of self-catalyzed transposition in tobacco.

Lymph node yield in rectal cancer surgery: effect of preoperative chemoradiotherapy

AIM

Adequate lymph node resection in rectal cancer is important for staging and local control. This study aims to verify the effect of neoadjuvant chemoradiation, as well as some clinicopathological features, on the yield of lymph nodes in rectal carcinoma.

METHODS

Data on consecutive patients who had total mesorectal excision for rectal adenocarcinoma at a single cancer center between January 2003 and July 2008 were reviewed. No patient had any prior pelvic surgery or radiotherapy. Patients had neoadjuvant chemoradiotherapy if they were stage II or III.

RESULTS

A total of 116 patients were included. The mean age was 53 years (range 29-83). Fifty-nine patients (51%) received neoadjuvant therapy before resection. The mean number of lymph nodes removed was 18 (range 4-67) per specimen. There was less lymph node yield in patients who received neoadjuvant therapy (16 vs. 19, p = 0.008). Only 64% of patients who had preoperative therapy had 12 lymph nodes or more in the specimen as opposed to 88% of those who had surgery upfront (p = 0.003). Other factors associated with lower lymph node yield included: female sex (p = 0.03) and tumour location in the lower rectum (p = 0.002). Age, tumour stage and grade, type of operation and surgical delay did not affect the number of lymph nodes removed.

CONCLUSION

Preoperative chemoradiotherapy for rectal cancer results in reduction in lymph node yield. Female sex and lower rectal tumours are also associated with retrieval of fewer lymph nodes.

Predicting maternal parenting stress in middle childhood: the roles of child intellectual status, behaviour problems and social skills

BACKGROUND

Parents of children with intellectual disabilities (ID) typically report elevated levels of parenting stress, and child behaviour problems are a strong predictor of heightened parenting stress. Interestingly, few studies have examined child characteristics beyond behaviour problems that may also contribute to parenting stress. The present longitudinal study examined the contribution of child social skills to maternal parenting stress across middle childhood, as well as the direction of the relationship between child social skills and parenting stress.

METHOD

Families of children with ID (n = 74) or typical development (TD) (n = 115) participated over a 2-year period. Maternal parenting stress, child behaviour problems and child social skills were assessed at child ages six and eight.

RESULTS

Child social skills accounted for unique variance in maternal parenting stress above and beyond child intellectual status and child behaviour problems. As the children matured, there was a significant interaction between child social skills and behaviour problems in predicting parenting stress. With respect to the direction of these effects, a cross-lagged panel analysis indicated that early parenting stress contributed to later social skills difficulties for children, but the path from children's early social skills to later parenting stress was not supported, once child behaviour problems and intellectual status were accounted for.

CONCLUSION

When examining parenting stress, child social skills are an important variable to consider, especially in the context of child behaviour problems. Early parenting stress predicted child social skills difficulties over time, highlighting parenting stress as a key target for intervention.

Increased maternofetal calcium flux in parathyroid hormone-related protein-null mice

The role of parathyroid hormone-related protein (PTHrP) in fetal calcium homeostasis and placental calcium transport was examined in mice homozygous for the deletion of the PTHrP gene (PTHrP^−/− null; NL) compared to PTHrP^+/+ (wild-type; WT) and PTHrP^+/− (heterozygous; HZ) littermates. Fetal blood ionized calcium was significantly reduced in NL fetuses compared to WT and HZ groups at 18 days of pregnancy (dp) with abolition of the fetomaternal calcium gradient. In situ placental perfusion of the umbilical circulation at 18 dp was used to measure unidirectional clearance of ⁴⁵Ca across the placenta in maternofetal (^CaK_mf) and fetoplacental (^CaK_fp) directions; ^CaK_fp was < 5% of ^CaK_mf for all genotypes. At 18 dp, ^CaK_mf across perfused placenta and intact placenta (^CaK_mf(intact)) were similar and concordant with net calcium accretion rates in vivo. ^CaK_mf was significantly raised in NL fetuses compared to WT and HZ littermates. Calcium accretion was significantly elevated in NL fetuses by 19 dp. Placental calbindin-D_9K expression in NL fetuses was marginally enhanced (P < 0.07) but expression of TRPV6/ECaC2 and plasma membrane Ca²⁺-ATPase (PMCA) isoforms 1 and 4 were unaltered. We conclude that PTHrP is an important regulator of fetal calcium homeostasis with its predominant effect being on unidirectional maternofetal transfer, probably mediated by modifying placental calbindin-D_9K expression. In situ perfusion of mouse placenta is a robust methodology for allowing detailed dissection of placental transfer mechanisms in genetically modified mice.

Cardiopulmonary bypass surgery in a patient with paroxysmal nocturnal haemoglobinuria

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare acquired haemolytic anaemia. Cardiac bypass surgery in patients with PNH may be complicated by aggravation of haemolysis in addition to increased risk of infection, renal failure, bleeding and thrombosis. We describe a case of uncomplicated cardiopulmonary bypass surgery for aortic valve replacement and aortoplasty in a patient with PNH and discuss some recommendations to reduce the risk of peri-operative complications.

Artificial Perfusion of the Fetal Circulation of the In situ Mouse Placenta: Methodology and Validation

Here we present methodology and validation (including measurement of unidirectional maternofetal clearance (Kmf) of (45)Ca and (14)C-mannitol) for in situ perfusion of the mouse placenta. On day 18 of gestation (term=19 days) mice were anaesthetised and the uterus delivered into a saline bath (40 degrees C). A fetus was selected, the umbilical artery and vein catheterised and perfused with Krebs Ringer (pH 7.4) at 60 microl/min. (45)Ca/(14)C-mannitol (2 microCi/5 microCi in 50 microl saline) was injected via maternal tail vein. Perfusate samples were collected every 5 min for 45 min. Maternal carotid artery pressure was monitored throughout perfusion. A terminal maternal cardiac blood sample was taken and analysed. Placentas were immersion fixed and processed for electron microscopy. Kmf for (45)Ca and (14)C-mannitol was calculated as perfusate [(45)Ca or (14)C-mannitol] x perfusion rate/maternal plasma [(45)Ca or (14)C-mannitol]xplacental weight. Maternal cardiac blood chemistry at termination (n=8-15, mean+/-SEM) was as follows: pH 7.153+/-0.016, PCO(2) 45.48+/-2.06 mmHg, PO(2) 66.47+/-7.10 mmHg, Na(+) 151.4+/-1.2 mmol/l, K(+) 5.54+/-0.17 mmol/l, Ca(2+) 1.15+/-0.03 mmol/l, glucose 7.2+/-0.5 mmol/l, and lactate 1.76+/-0.77 mmol/l. A successful 45 min perfusion in which perfusate recovery was >95% occurred in >50% of animals. Perfusion did not alter placental morphology or carotid pressure. Kmf (microl/min/g placenta) for (45)Ca (66.0+/-8.4 (n=7)) was significantly higher than Kmf for (14)C-mannitol (20.0+/-2.4 (n=5)) (p<0.01). These data demonstrate physiological perfusion of the mouse placenta in situ and its usefulness for measurement of solute transfer.