Optimal size threshold for PIRADSv2 category 5 upgrade and its positive predictive value: is it predictive of "very high" likelihood of clinically-significant cancer?

AIM

To identify the optimal size metric and threshold for Prostate Imaging Reporting and Data System (PIRADS) 5 upgrade, calculate its positive predictive value (PPV) for clinically-significant prostate cancer (csPCA), and determine if it is indicative of a "very high" likelihood of csPCA.

MATERIALS AND METHODS

One hundred and forty-three PIRADS 4 or 5 lesions were evaluated. Lesion diameters were used to calculate lesion volume (LV). Pearson correlation between maximum lesion diameter (MLD) and LV was calculated. Area under the curve (AUC) for discriminating csPCA (Gleason grade ≥ 3 + 4) was calculated using MLD and LV. Optimal size thresholds (using Youden index) and highly predictive size thresholds were identified for the whole prostate (WP), peripheral zone (PZ), and transitional zone (TZ).

RESULTS

There was high correlation between MLD and LV (r=0.77-0.81), with comparable AUCs for MLD and LV in the identification of csPCA in the WP (0.73, 0.72), PZ (0.73, 0.73), and TZ (0.79, 0.75). Optimal MLD thresholds were 1.4, 1.4, and 1.6 cm in the WP, PZ, and TZ respectively, with PPVs of 76%, 81%, and 69%, respectively. An MLD threshold of 2.7 cm would be needed in the WP to achieve a PPV approaching 90%, with sensitivity decreasing to 10%.

CONCLUSIONS

There is high correlation between MLD and LV with comparable discrimination of csPCA using each. PIRADSv2's 1.5 cm MLD threshold is near the optimal threshold for PIRADS 5 upgrade but has moderate PPV. A much higher threshold would be needed to increase its PPV, with significant sacrifice in sensitivity.

How Quality Control Systems AID Sec-Dependent Protein Translocation

The evolutionarily conserved Sec machinery is responsible for transporting proteins across the cytoplasmic membrane. Protein substrates of the Sec machinery must be in an unfolded conformation in order to be translocated across (or inserted into) the cytoplasmic membrane. In bacteria, the requirement for unfolded proteins is strict: substrate proteins that fold (or misfold) prematurely in the cytoplasm prior to translocation become irreversibly trapped in the cytoplasm. Partially folded Sec substrate proteins and stalled ribosomes containing nascent Sec substrates can also inhibit translocation by blocking (i.e., “jamming”) the membrane-embedded Sec machinery. To avoid these issues, bacteria have evolved a complex network of quality control systems to ensure that Sec substrate proteins do not fold in the cytoplasm. This quality control network can be broken into three branches, for which we have defined the acronym “AID”: (i) avoidance of cytoplasmic intermediates through cotranslationally channeling newly synthesized Sec substrates to the Sec machinery; (ii) inhibition of folding Sec substrate proteins that transiently reside in the cytoplasm by molecular chaperones and the requirement for posttranslational modifications; (iii) destruction of products that could potentially inhibit translocation. In addition, several stress response pathways help to restore protein-folding homeostasis when environmental conditions that inhibit translocation overcome the AID quality control systems.

The C-terminal tail of the bacterial translocation ATPase SecA modulates its activity

In bacteria, the translocation of proteins across the cytoplasmic membrane by the Sec machinery requires the ATPase SecA. SecA binds ribosomes and recognises nascent substrate proteins, but the molecular mechanism of nascent substrate recognition is unknown. We investigated the role of the C-terminal tail (CTT) of SecA in nascent polypeptide recognition. The CTT consists of a flexible linker (FLD) and a small metal-binding domain (MBD). Phylogenetic analysis and ribosome binding experiments indicated that the MBD interacts with 70S ribosomes. Disruption of the MBD only or the entire CTT had opposing effects on ribosome binding, substrate-protein binding, ATPase activity and in vivo function, suggesting that the CTT influences the conformation of SecA. Site-specific crosslinking indicated that F399 in SecA contacts ribosomal protein uL29, and binding to nascent chains disrupts this interaction. Structural studies provided insight into the CTT-mediated conformational changes in SecA. Our results suggest a mechanism for nascent substrate protein recognition.

The Perceptions of Patients, their Parents and Healthcare Providers on the Transition of Young Adults with Type 1 Diabetes to Adult Services in the West of Ireland

Aim This study aims to describe the perceptions of young adults’, parents of young adults’ and health care professionals’ (HCPs) of the transition process for young adults with Type 1 Diabetes in the West of Ireland. Methods Thematic analysis of semi-structured interviews conducted with the three stakeholder groups was performed. Results Young adults hardly noticed the transition, with many of them seeing it as a physical move, whereas parents were more anxious and felt their involvement was still needed but not accommodated. Both groups perceived the young adults’ ability to manage their diabetes as a facilitator, as well as the continuity of care provided by the diabetes nurse. Resource limitations and an inability of a young adult to self-manage were identified as barriers to smooth transition by parents, whilst HCPs were experiencing problems with non-attendance and a lack of a psychology service. Conclusion This study highlights the importance of encouraging adolescents’ autonomy in the years leading to transition. A key healthcare professional link between both services appears to facilitate smooth transition. Being flexible and supportive of both parents and adolescents including the provision of mental health services are other important considerations.

Isolated cervical recurrence of squamous cell carcinoma in the previously treated neck

PURPOSE

Our study goal was to identify clinical factors associated with, and that might predict, treatment outcome for patients with an isolated cervical recurrence of squamous cell carcinoma in the previously treated neck (ICR-PTN).

MATERIALS AND METHODS

We reviewed all patients with noncutaneous head and neck squamous cell carcinoma treated at our tertiary care center between 1987 and 1997, and identified 17 patients (2%) who later developed an isolated recurrence in a previously treated neck. These patients made up our study group, and their charts were thoroughly reviewed. Outcome of salvage therapy (surgery, radiation, or combined therapy) for these patients was compared with pooled clinicopathologic data using the Fisher exact test (one tail).

RESULTS

Fifteen such ICR-PTN patients consented to salvage therapy. Six patients were without disease at last follow-up, and 3 were successfully palliated. A statistically significant association between the side of ICR-PTN relative to the primary tumor and outcome of salvage therapy (P =.026) was noted, with ipsilateral neck recurrence being a favorable prognostic factor. Trends that did not meet the standard for statistical significance were observed between a better outcome of salvage therapy and the following parameters: age of less than 60, nonsurgical initial treatment of the neck, and lack of a history of a recurrence before they developed the ICR-PTN.

CONCLUSIONS

The current study showed that only the side of the ICR-PTN relative to the primary site is associated with outcome of salvage therapy. Based on our findings and a review of the literature, we have developed a summary of factors that might predict which patients with an ICR-PTN are most likely to benefit from aggressive salvage therapy.