The next generation of PI3K-Akt-mTOR pathway inhibitors in breast cancer cohorts

The PI3K/Akt/mTOR pathway plays a role in various oncogenic processes in breast cancer and key pathway aberrations have been identified which drive the different molecular subtypes. Early drugs developed targeting this pathway produced some clinical success but were hampered by pharmacokinetics, tolerability and efficacy problems. This created a need for new PI3K pathway-inhibiting drugs, which would produce more robust results allowing incorporation into treatment regimens for breast cancer patients. In this review, the most promising candidates from the new generation of PI3K-pathway inhibitors is explored, presenting evidence from preclinical and early clinical research, as well as ongoing trials utilising these drugs in breast cancer cohorts. The problems hindering the development of drugs targeting the PI3K pathway are examined, which have created problems for their use as monotherapies. PI3K pathway inhibitor combinations therefore remains a dynamic research area, and their role in combination with immunotherapies and epigenetic therapies is also inspected.

Critcomms: a national cross-sectional questionnaire based study to investigate prehospital handover practices between ambulance clinicians and specialist prehospital teams in Scotland

BACKGROUND

Poor communication during patient handover is recognised internationally as a root cause of a significant proportion of preventable deaths. Improving the accuracy and quality of handover may reduce associated mortality and morbidity. Although the practice of handover between Ambulance and Emergency Department clinicians has received some attention over recent years there is little evidence to support handover best practice within the prehospital domain. Further research is therefore urgently required to understand the most appropriate way to deliver clinical information exchange in the pre-hospital environment. We aimed to investigate current clinical information exchange practices, perceived challenges and the preferred handover mnemonic for use during transfer of high acuity patients between ambulance clinicians and specialist prehospital teams.

METHODS

A national, cross-sectional questionnaire study. Participants were road based ambulance clinicians (RBAC) or active members of specialist prehospital teams (SPHT) based in Scotland.

RESULTS

Over a three month study period there were 247 prehospital incidents involving specialist teams. One hundred ninety individuals completed the questionnaire; 61% [n = 116] RBAC and 39% [n = 74] SPHT. Median length of prehospital experience was 10 years (IQR 5-18). Overall current prehospital handover practices were perceived as being effective (Mdn 4.00; IQR 3-4 [1 = very ineffective - 5 = very effective]) although SPHT clinicians rated handover effectiveness slightly lower than RBAC's (Mdn 3.00 vs 4.00, U = 1842.5, p = .03). 'ATMIST' (Age, Time of onset, Medical complaint/injury, Investigation, Signs and Treatment) was deemed the mnemonic of choice. The clinical variables perceived as essential for handover are not explicitly identified within the SBAR mnemonic. The most frequently reported method of recording and transferring information during handover was via memory (n = 112 and n = 120 respectively) and 'interruptions' were perceived as the most significant barrier to effective handover.

CONCLUSION

While, overall, current prehospital handover practice is perceived as effective this study has identified a number of areas for improvement. These include the development of a shared mental model through system standardisation, innovations to support information recording and delivery, and the clear identification at incidents of a handover lead. Mnemonics must be carefully selected to ensure they explicitly contain the perceived essential clinical variables required for prehospital handover; the mnemonic ATMIST meets these requirements. New theoretically informed, evidence-based interventions, must be developed and tested within existing systems of care to minimise information loss and risk to patients.

Raman spectroscopy for cytopathology of exfoliated cervical cells

Cervical cancer is the fourth most common cancer affecting women worldwide but mortality can be decreased by early detection of pre-malignant lesions. The Pap smear test is the most commonly used method in cervical cancer screening programmes. Although specificity is high for this test, it is widely acknowledged that sensitivity can be poor mainly due to the subjective nature of the test. There is a need for new objective tests for the early detection of pre-malignant cervical lesions. Over the past two decades, Raman spectroscopy has emerged as a promising new technology for cancer screening and diagnosis. The aim of this study was to evaluate the potential of Raman spectroscopy for cervical cancer screening using both Cervical Intraepithelial Neoplasia (CIN) and Squamous Intraepithelial Lesion (SIL) classification terminology. ThinPrep® Pap samples were recruited from a cervical screening population. Raman spectra were recorded from single cell nuclei and subjected to multivariate statistical analysis. Normal and abnormal ThinPrep® samples were discriminated based on the biochemical fingerprint of the cells using Principal Component Analysis (PCA). Principal Component Analysis - Linear Discriminant Analysis (PCA-LDA) was employed to build classification models based on either CIN or SIL terminology. This study has shown that Raman spectroscopy can be successfully applied to the study of routine cervical cytology samples from a cervical screening programme and that the use of CIN terminology resulted in improved sensitivity for high grade cases.

Multiple pathways facilitate the biogenesis of mammalian tail-anchored proteins

Tail-anchored (TA) proteins are transmembrane proteins with a single C-terminal transmembrane domain, which functions as both their subcellular targeting signal and membrane anchor. We show that knockout of TRC40 in cultured human cells has a relatively minor effect on endogenous TA proteins, despite their apparent reliance on this pathway in vitro. These findings support recent evidence that the canonical TRC40 pathway is not essential for TA protein biogenesis in vivo. We therefore investigated the possibility that other ER-targeting routes can complement the TRC40 pathway and identified roles for both the SRP pathway and the recently described mammalian SND pathway in TA protein biogenesis. We conclude that, although TRC40 normally plays an important role in TA protein biogenesis, it is not essential, and speculate that alternative pathways for TA protein biogenesis, including those identified in this study, contribute to the redundancy of the TRC40 pathway.

Summary: In addition to the canonical TRC40-targeting pathway, mammalian tail-anchored proteins can also utilise the SRP and SND pathways to facilitate their insertion into the ER membrane.

Intra- and inter-observer reproducibility of CINtec® PLUS in ThinPrep® cytology preparations

BACKGROUND

This study evaluated the intra- and inter-observer reproducibility of the dual-stain biomarker, CINtec^® PLUS cytology in ThinPrep^® specimens, for improved specificity in the detection of cervical disease in women testing human papillomavirus (HPV) positive.

METHODS

A total of 972 cases of HPV-positive women from a triage and primary HPV screening population were selected from an ongoing study evaluating the clinical performance of CINtec^® PLUS cytology. For reproducibility analyses, three cytotechnologists rescreened sets of slides which they had previously reported themselves and which were previously reported by each of the other cytotechnologists. The original results of slides previously screened by each of the three cytotechnologists were also compared with the results of an expert reference evaluator.

RESULTS

Intra- and inter-observer agreement for paired evaluations between reviewers ranged from 82.8% to 94.9% (kappa 0.65-0.91) and 89.2% to 93% (kappa 0.83-0.88), respectively. Reproducibility analyses between the cytotechnologists and the reference evaluator revealed agreements ranging from 95.5% to 98% (kappa 0.89-0.96).

CONCLUSION

Evaluation of the dual-stain biomarker showed a high level of agreement across all evaluators suggesting that CINtec^® PLUS cytology will perform well in the hands of cytotechnologists and pathologist reviewers and could be introduced into cellular pathology laboratories that employ ThinPrep^® LBC with a minimum effort.

Mycolactone reveals the substrate-driven complexity of Sec61-dependent transmembrane protein biogenesis

Mycolactone is the exotoxin virulence factor produced by Mycobacterium ulcerans, the pathogen responsible for Buruli ulcer. The skin lesions and immunosuppression that are characteristic of this disease result from the action of mycolactone, which targets the Sec61 complex and inhibits the co-translational translocation of secretory proteins into the endoplasmic reticulum. In this study, we investigate the effect of mycolactone on the Sec61-dependent biogenesis of different classes of transmembrane protein (TMP). Our data suggest that the effect of mycolactone on TMP biogenesis depends on how the nascent chain initially engages the Sec61 complex. For example, the translocation of TMP lumenal domains driven by an N-terminal cleavable signal sequence is efficiently inhibited by mycolactone. In contrast, the effect of mycolactone on protein translocation that is driven solely by a non-cleavable signal anchor/transmembrane domain depends on which flanking region is translocated. For example, while translocation of the region N-terminal to a signal anchor/transmembrane domain is refractive to mycolactone, C-terminal translocation is efficiently inhibited. Our findings highlight the diversity of Sec61-dependent translocation and provide a molecular basis for understanding the effect of mycolactone on the biogenesis of different TMPs.

Highlighted Article: The exotoxin mycolactone interferes with the biogenesis of the majority of transmembrane proteins and its actions highlight differences in how distinct classes of these proteins initially engage the Sec61 translocon.

Controlling wettability of PECVD-deposited dual organosilicon/carboxylic acid films to influence DNA hybridisation assay efficiency

Plasma oxidation of Zeonor and deposition of TEOS/AA thin film showing dual layer effect on the surface.

Normobaric hyperoxia training in elite female hockey players

BACKGROUND

Supplemental oxygen use may offer recovery benefits to team sport athletes both in training and match play. A blinded independent measures study was used to investigate the effect of supplementary oxygen use during recovery from high-intensity exercise on performance.

METHODS

Fifteen female international hockey players underwent a 6 week running based training program with a 2:1 work to rest ratio. The subjects were split into 3 groups; normobaric hyperoxia (HXA), normoxia (NXA) and control (CTR). In between exercise sets HXA received 100% oxygen for 1 minute whilst NXA received a placebo in the same manner. CTR received no treatment and were not supervised. Maximal aerobic speed (MAS) was measured pre and post. Distance covered was measured along with peak heart rate (HRpeak), peak blood lactate concentration ([La-]peak) and rate of perceived exertion (RPE).

RESULTS

MAS improved in HXA, NXA and CTR. However, distance ran in training was not different between groups. There was a likely positive effect on HRpeak in HXA (lower in HXA). RPE and [La-]peak response was not different between groups.

CONCLUSIONS

Inhaling supplementary oxygen during recovery between high-intensity intervals did not improve physiological performance of high-level team sport players. The normobaric hyperoxia treatment had no effect on maximal aerobic (distance covered), metabolic ([La-]peak), and perception (RPE) parameters. It is not recommended as an ergogenic aid to training at sea level.

REGULATION OF AUSTRALIAN MEDICAL PROFESSIONALS AND NATIONAL SECURITY: LESSONS FROM THREE CASE STUDIES

In recent times, Australia's national security concerns have had controversial impacts on regulation of Australian medical practitioners in areas related to immigration detention. This column explores three recent case studies relevant to this issue. The first involves the enactment of the Australian Border Force Act 2015 (Cth), which has a significant impact on the regulation of medical professionals who work with people in immigration detention. The second involves the decision of the High Court of Australia in Plaintiff M68/2015 v Minister for Immigration and Border Protection [2016] HCA 1 that an amendment to Australian federal legislation justified sending children back to immigration detention centres in Papua New Guinea and Nauru. This legislation was previously heavily criticised by the Australian Human Rights Commissioner. The third concerns the deregistration of Tareq Kamleh, an Australian doctor of German-Palestinian heritage who came to public attention on ANZAC Day 2015 with his appearance online in a propaganda video for the Islamic State terrorist organisation al-Dawla al-Islamyia fil Iraq wa'al Sham, also known as Islamic State of Iraq and Syria (ISIS) or Daesh. Australia's professional regulatory system should presumptively respect professional virtues, such as loyalty to the relief of individual patient suffering, when dealing with doctors (whether in Australia or ISIS-occupied Syria) working under regimes whose principles appear inconsistent with those of ethics and human rights.

HPV16 and HPV18 genotyping triage in young women with borderline cytology or mild dyskaryosis: effect of age on genotype-specific risk of high-grade CIN

OBJECTIVE

Human papillomavirus (HPV) triage of borderline cytology or mild dyskaryosis is limited by the higher prevalence of HPV in women with these findings relative to those with high-grade cervical intraepithelial neoplasia (≥CIN2). This is particularly relevant in young women in whom HPV prevalence is discernible. In a previous analysis of HPV triage and colposcopy outcomes in Northern Ireland, we revealed a substantial amount of prevalent high-grade disease in women below 30 years of age. We explored the role of genotyping for HPV16/HPV18 in this population by assessing the risk of high-grade lesions associated with these genotypes and the effect of age on type-specific risk.

METHODS

Of the 866 women eligible for HPV triage, those who tested positive for HPV were referred to colposcopy. The relative risk of ≥CIN2 for HPV16, HPV18 and non-HPV16/18 high-risk genotype positivity was determined for cobas(®) HPV Test-positive results.

RESULTS

The relative risk of high-grade CIN was significantly greater in women infected with HPV16 and/or HPV18 compared with non-HPV16/18 infections, regardless of age (2.23 and 0.45, respectively). In women under 30 years of age, HPV16-associated risk of ≥CIN2 was significantly greater than that of HPV18 and the non-HPV16/18 genotypes (1.74 versus 1.03 and 0.58, respectively). In women aged ≥30 years, HPV18 infection presented the greatest risk of ≥CIN2 (3.03). The relative risk of ≥CIN2 associated with non-HPV16/18 genotypes was lower (range, 0.32-0.58) for both age groups.

CONCLUSION

This analysis demonstrates the value of genotyping for HPV16/HPV18 and age stratification to improve the specificity of HPV triage and to tailor management relative to the risk of high-grade CIN and cancer.

Mechanistic insights into the inhibition of Sec61-dependent co- and post-translational translocation by mycolactone

The virulence factor mycolactone is responsible for the immunosuppression and tissue necrosis that characterise Buruli ulcer, a disease caused by infection with Mycobacterium ulcerans In this study, we confirm that Sec61, the protein-conducting channel that coordinates entry of secretory proteins into the endoplasmic reticulum, is a primary target of mycolactone, and characterise the nature of its inhibitory effect. We conclude that mycolactone constrains the ribosome-nascent-chain-Sec61 complex, consistent with its broad-ranging perturbation of the co-translational translocation of classical secretory proteins. In contrast, the effect of mycolactone on the post-translational ribosome-independent translocation of short secretory proteins through the Sec61 complex is dependent on both signal sequence hydrophobicity and the translocation competence of the mature domain. Changes to protease sensitivity strongly suggest that mycolactone acts by inducing a conformational change in the pore-forming Sec61α subunit. These findings establish that mycolactone inhibits Sec61-mediated protein translocation and highlight differences between the co- and post-translational routes that the Sec61 complex mediates. We propose that mycolactone also provides a useful tool for further delineating the molecular mechanisms of Sec61-dependent protein translocation.

Use of an integrated modelling and simulation approach to develop a simplified peginterferon alfa-2a dosing regimen for children with hepatitis C

AIM

The aim of the study was to simplify the dosing regimen of peginterferon alfa-2a in paediatric patients with chronic hepatitis C.

METHODS

A population pharmacokinetic (PK) model was developed using PK data from 14 children aged 2-8 years and 402 adults. Simulations were produced to identify a simplified dosing regimen that would provide exposures similar to those observed in the paediatric clinical trials and in the range known to be safe/efficacious in adults. Model predictions were evaluated against observed adult and paediatric data to reinforce confidence of the proposed dosing regimen.

RESULTS

The final model was a two compartment model with a zero order resorption process. Covariates included a linear influence of body surface area (BSA) on apparent oral clearance (CL/F) and a linear influence of body weight on apparent volume of distribution of the central compartment (V1 /F). A simplified dosing regimen was developed which is expected to provide exposures in children aged ≥5 years similar to the dosing formula used in the paediatric clinical trial and within the range that is safe/efficacious in adults. This simplified regimen is approved in the EU and in other countries for the treatment of chronic hepatitis C in treatment-naive children/adolescents aged ≥5 years in combination with ribavirin.

CONCLUSION

Pre-existing adult PK data were combined with relatively limited paediatric PK data to develop a PK model able to predict exposure in both populations adequately. This provided increased confidence in characterizing PK in children and helped in the development of a simplified dosing regimen of peginterferon alfa-2a in paediatric patients.

Potential of 3D printing technologies for fabrication of electron bolus and proton compensators

In electron and proton radiotherapy, applications of patient-specific electron bolus or proton compensators during radiation treatments are often necessary to accommodate patient body surface irregularities, tissue inhomogeneity, and variations in PTV depths to achieve desired dose distributions. Emerging 3D printing technologies provide alternative fabrication methods for these bolus and compensators. This study investigated the potential of utilizing 3D printing technologies for the fabrication of the electron bolus and proton compensators. Two printing technologies, fused deposition modeling (FDM) and selective laser sintering (SLS), and two printing materials, PLA and polyamide, were investigated. Samples were printed and characterized with CT scan and under electron and proton beams. In addition, a software package was developed to convert electron bolus and proton compensator designs to printable Standard Tessellation Language file format. A phantom scalp electron bolus was printed with FDM technology with PLA material. The HU of the printed electron bolus was 106.5 ± 15.2. A prostate patient proton compensator was printed with SLS technology and polyamide material with -70.1 ± 8.1 HU. The profiles of the electron bolus and proton compensator were compared with the original designs. The average over all the CT slices of the largest Euclidean distance between the design and the fabricated bolus on each CT slice was found to be 0.84 ± 0.45 mm and for the compensator to be 0.40 ± 0.42 mm. It is recommended that the properties of specific 3D printed objects are understood before being applied to radiotherapy treatments.

Human papillomavirus testing in young women: clinical outcomes of human papillomavirus triage in a UK cervical screening program

BACKGROUND

In the United Kingdom, human papillomavirus (HPV) testing is used to triage women with borderline cytology or mild dyskaryosis; however, in young women, the value of triage is limited by the high HPV prevalence rate. The current study examined the impact of HPV triage on colposcopy referral, colposcopy procedures, and patient outcome in a cervical screening population that included women aged < 25 years.

METHODS

Women aged 18 to 65 years attending for cervical screening in Northern Ireland were tested for HPV if their cytology result demonstrated borderline cytology or mild dyskaryosis. Of the 866 women eligible for HPV triage, those who tested negative for HPV were returned to routine screening and women who tested positive were referred to colposcopy.

RESULTS

HPV prevalence was 82.07% in women aged < 25 years and 54.69% in women aged ≥ 25 years. Colposcopy referrals increased by 42.67%. The odds of undergoing a large loop excision of the transformation zone (LLETZ) compared with punch biopsy increased by 0.056 per year above the age of 31 years. LLETZ performed in women aged ≥ 25 years and those aged < 25 years yielded rates of cervical intraepithelial neoplasia of type 2 or higher (≥ CIN2) of 57.04% and 80.00%, respectively. The positive predictive value of HPV triage for detecting ≥ CIN2 was 29.92% in women aged < 25 years and 27.51% in the older age group.

CONCLUSIONS

HPV triage substantially increased colposcopy referrals. The positive predictive value of a positive HPV test to detect ≥ CIN2 was not affected by age. LLETZ performed in women aged < 25 years yielded higher rates of ≥ CIN2 compared with the older age group.