Distinct Dynamics of Mitotic Transition in B-Cell Lymphoma and Reactive B-Cell Lymphoproliferations Determined by H3S10 Phosphohistone Immunolabeling.

OBJECTIVES: Clonal selection in the follicular germinal centers in lymphatic tissues is accompanied by an intense proliferation of polyclonal B cells in a precisely regulated fashion. In contrast, B-cell neoplasias proliferate autonomously due to endogenous stimuli. The cell kinetic activity is obvious at many levels including progressive chromatin modification and elevated mitotic rates. We asked if there are differences in the kinetics of histone H3S10 phosphorylation required for mitotic entry between highly proliferating B cells of reactive germinal centers and in B-cell lymphomas with different proliferative capacity. MATERIAL AND METHODS: Phospho-H3 histone (pH3S10)-specific immunohistochemistry was applied to cultivated cell, reactive and selected indolent and aggressive lymphoma samples (diffuse large B-cell lymphoma, Burkitt lymphoma, lymphoblastic lymphoma, follicular lymphoma and small lymphocytic lymphoma). Microscopic quantification of the "dot-type" (representing late G2 phase) and "mitotic" immunolabeling patterns per field of view was performed and compared with classical cell proliferation markers. RESULTS: In addition to the dense homogeneous chromatin labeling highlighting mitotic figures, we stated a selective dot-type nuclear labeling representing ongoing chromatin condensation in premitotic G2 phase cells. While cell proliferation and mitotic counts correlated in general with histology, statistical analysis indicated an accumulation of G2 phase pH3S10 pattern in the reactive germinal centers in contrast to lymphomas. The dot-type G2 staining pattern was surprisingly overrepresented (1,321.7 ± 356.5/10 HPF) in the reactive germinal centers compared to aggressive lymphomas (101.3 ± 33.1) (p < 0.005). The relative G2/M value was significantly higher (4.6 ± 0.6) in reactive germinal center B cells than in any lymphoma entity evaluated (0.7 ± 0.2 in Burkitt lymphoma, 0.9 ± 0.4 in grade 3b follicular lymphoma, 1.3 ± 1.1 in diffuse large B-cell lymphoma, 1.5 ± 0.6 in lymphoblastic lymphoma, and 0.9 ± 0.2 in small lymphocytic lymphoma). CONCLUSIONS: pH3S10 immunohistochemistry enabled the presentation of significant differences in the cell cycle kinetics between reactive and neoplastic B-cell lymphoproliferations. Accumulation of G2 phase B cells in reactive folliculi directs to physiological G2/M checkpoint blockade. In contrast, accelerated G2/M transition in lymphomas is potentially associated with impaired genomic repair and cell death mechanisms.

Hands-on teaching, shadowing, and supported learning through acute clinics to help improve the confidence of and meet training needs for junior doctors working in ear, nose, and throat surgery.

BACKGROUND: Ear, nose, and throat (ENT) surgery is a niche and unique specialty that has been recognized as being poorly taught throughout medical school and postgraduate training. Junior doctors who rotate into this specialty often find it hard and struggle to manage patients. Aims: The aim of this study was to devise a junior doctor-focused induction program with specific emphasis on shadowing and partnered working to improve confidence and competence. METHODS: Feedback from previous trainees was used to identify valuable training opportunities within the 4-month rotation. Trainers identified clinical areas where supported learning could be delivered. Trainees were allocated to rotate between theater, ward, on-call shifts, and acute clinics. The degree of time spent in each area was analyzed in order to balance service provision vs learning needs. Furthermore, novel strategies were introduced in each session to maximize learning experiences. Junior doctors were aware of the opportunities that would be available to them at the start of the rotation. In order to assess whether the aims were met, a questionnaire survey was used to assess exposure to core ENT practical skills and junior doctors' confidence levels in carrying them out unsupervised. RESULTS: Junior doctors spent 40% of their time assessing new acute admissions. Twenty percent of time was spent in ENT clinic, but novel practical methods of induction were introduced such as 1 week of directly supervised shadowing, followed by a transition period with regular debrief. A three-stage model was used to offer training in practical procedures in the clinical setting. Over half of the trainees felt confident in undertaking 50% of the core ENT procedures unsupervised. CONCLUSION: Our study reveals that giving junior doctors a relevant, focused and appropriate induction helps orientate them, give them the opportunity to ask questions, and also find their grounding in order to begin working. Having dedicated time to shadow and be with a colleague to assess and treat patients initially, with ongoing telephone and in person support, ensured that their confidence and competence improved very quickly. It also improved workplace satisfaction and motivated doctors to undertake self-directed learning and improve and enhance their skills beyond the minimum.