Identified or conflicted: a latent class and regression tree analysis explaining how identity constructs cluster within smokers

Identity, or ‘who I am’, is important for smoking behaviour. Identity constructs (parts of a person’s identity) are typically examined as separate entities, but emerging evidence suggests that the multifaceted nature of identity is relevant in the context of smoking. This cross-sectional study examined how smoking-related self- and group-identity constructs cluster within adult daily smokers (N = 231), whether classes of smokers can be distinguished based on clusters of identity constructs, and which factors explain class membership. Data were collected online in The Netherlands and Belgium, 2017–2018. Latent class and regression tree analyses showed that participants in Class 1 of ‘Identified smokers’ (estimated population share 54%) reported stronger smoker self- and group-identities, stronger expected identity loss when quitting smoking, and weaker quitter self-identities and non-smoker self- and group-identities (vs. Class 2 of ‘Conflicted smokers’). Class membership was explained by the interaction between mental smoking dependence (dominant explanatory variable), consideration of future consequences, age of smoking onset, self-efficacy, and future self thought clarity. Models had good fit. The identity of more dependent smokers is more strongly oriented toward smoking. Smoking is also more strongly embedded in the identity of smokers who started smoking young, are less inclined to think about the future, and have lower self-efficacy.

Local recurrence following breast-conserving treatment in women aged 40 years or younger: trends in risk and the impact on prognosis in a population-based cohort of 1143 patients

AIM

To evaluate trends in the risk of local recurrences after breast-conserving treatment (BCT) and to examine the impact of local recurrence (LR) on distant relapse-free survival in a large, population-based cohort of women aged ≤40 years with early-stage breast cancer.

METHODS

All women (n=1143) aged ≤40 years with early-stage (pT1-2/cT1-2, N0-2, M0) breast cancer who underwent BCT in the south of the Netherlands between 1988 and 2010 were included. BCT consisted of local excision of the tumour followed by irradiation of the breast.

RESULTS

After a median follow-up of 8.5 (0.1-24.6)years, 176 patients had developed an isolated LR. The 5-year LR-rate for the subgroups treated in the periods 1988-1998, 1999-2005 and 2006-2010 were 9.8% (95% confidence interval (CI) 7.1-12.5), 5.9% (95% CI 3.2-8.6) and 3.3% (95% CI 0.6-6.0), respectively (p=0.006). In a multivariate analysis, adjuvant systemic treatment was associated with a reduced risk of LR of almost 60% (hazard ratio (HR) 0.42; 95%CI 0.28-0.60; p<0.0001). Patients who experienced an early isolated LR (≤5 years after BCT) had a worse distant relapse-free survival compared to patients without an early LR (HR 1.83; 95% CI 1.27-2.64; p=0.001). Late local recurrences did not negatively affect distant relapse-free survival (HR 1.24; 95% CI 0.74-2.08; p=0.407).

CONCLUSION

Local control after BCT improved significantly over time and appeared to be closely related to the increased use and effectiveness of systemic therapy. These recent results underline the safety of BCT for young women with early-stage breast cancer.

Relationship between the two immunologically distinguishable forms of glucocerebrosidase in tissue extracts

Extracts of human spleen contain two immunologically distinguishable forms of glucocerebrosidase: form I is precipitable by polyclonal or monoclonal anti-(placental glucocerebrosidase) antibodies, whereas form II is not [Aerts, J. M. F. G., Donker-Koopman, W. E., Van der Vliet, M. F. K., Jonsson, L. M. V., Ginns, E. I., Murray, G. J., Barranger, J. A., Tager, J. M. & Schram, A. W. (1985) Eur. J. Biochem. 150, 565-574]. The proportion of form II glucocerebrosidase was high in extracts of spleen, liver and kidney and low in extracts of brain, placenta and fibroblasts. Furthermore, the proportion of form II enzyme was higher in a detergent-free aqueous extract of spleen than in a Triton X-100 extract of total spleen or splenic membranes. When form II glucocerebrosidase in a splenic extract was separated from form I enzyme by immunoaffinity chromatography and stored at 4 degrees C, a gradual conversion to form I enzyme occurred. The conversion was almost immediate if 30% (v/v) ethylene glycol was present. In the denatured state both forms of glucocerebrosidase reacted with anti-(placental glucocerebrosidase) antibodies. Form I glucocerebrosidase was stimulated by sodium taurocholate or sphingolipid-activator protein 2 (SAP-2), whereas form II enzyme exhibited maximal activity in the absence of the effectors. The pH activity profile of form II glucocerebrosidase was almost identical to that of form I enzyme in the presence of SAP-2. In the native state, form I glucocerebrosidase had a molecular mass of 60 kDa whereas that of form II glucocerebrosidase was about 200 kDa. After gel-permeation high-performance liquid chromatography of splenic extracts, the fractions with form II glucocerebrosidase contained material cross-reacting with both anti-(placental glucocerebrosidase) and anti-(SAP-2) antibodies. Preincubation of form I glucocerebrosidase with SAP-2 at pH 4.5 led to masking of the epitope on glucocerebrosidase reacting with monoclonal anti-(placental glucocerebrosidase) antibody 2C7. Furthermore, preincubation of form I glucocerebrosidase with monoclonal antibody 2C7 prevented activation of the enzyme by SAP-2. We propose that form I glucocerebrosidase is a monomeric form of the enzyme, whereas form II glucocerebrosidase is a high-Mr complex of the enzyme in association with sphingolipid-activator protein 2.