Strongly oversized fission yeast cells lack any size control and tend to grow linearly rather than bilinearly.

During the mitotic cycle, the rod-shaped fission yeast cells grow only at their tips. The newly born cells grow first unipolarly at their old end, but later in the cycle, the 'new end take-off' event occurs, resulting in bipolar growth. Photographs were taken of several steady-state and induction synchronous cultures of different cell cycle mutants of fission yeast, generally larger than wild type. Length measurements of many individual cells were performed from birth to division. For all the measured growth patterns, three different functions (linear, bilinear and exponential) were fitted, and the most adequate one was chosen by using specific statistical criteria, considering the altering parameter numbers. Although the growth patterns were heterogeneous in all the cultures studied, we could find some tendencies. In cultures with sufficiently wide size distribution, cells large enough at birth tend to grow linearly, whereas the other cells generally tend to grow bilinearly. We have found that among bilinearly growing cells, the larger they are at birth, the rate change point during their bilinear pattern occurs earlier in the cycle. This shifting near to the beginning of the cycle might finally cause a linear pattern, if the cells are even larger. In all of the steady-state cultures studied, a size control mechanism operates to maintain homeostasis. By contrast, strongly oversized cells of induction synchronous cultures lack any sizer, and their cycle rather behaves like an adder. We could determine the critical cell size for both the G1 and G2 size controls, where these mechanisms become cryptic. TAKE AWAY: Most individual fission yeast cells in steady-state cultures grow bilinearly. In strongly oversized fission yeast cells, linear growth dominates over bilinear. Above birth length thresholds, both the G1 and G2 size controls become cryptic.

First off-time treatment prostate-specific antigen kinetics predicts survival in intermittent androgen deprivation for prostate cancer.

BACKGROUND: Prostate-specific antigen (PSA) doubling time is relying on an exponential kinetic pattern. This pattern has never been validated in the setting of intermittent androgen deprivation (IAD). Objective is to analyze the prognostic significance for PCa of recurrent patterns in PSA kinetics in patients undergoing IAD. METHODS: A retrospective study was conducted on 377 patients treated with IAD. On-treatment period (ONTP) consisted of gonadotropin-releasing hormone agonist injections combined with oral androgen receptor antagonist. Off-treatment period (OFTP) began when PSA was lower than 4 ng/ml. ONTP resumed when PSA was higher than 20 ng/ml. PSA values of each OFTP were fitted with three basic patterns: exponential (PSA(t) = λ.e(αt)), linear (PSA(t) = a.t), and power law (PSA(t) = a.t(c)). Univariate and multivariate Cox regression model analyzed predictive factors for oncologic outcomes. RESULTS: Only 45% of the analyzed OFTPs were exponential. Linear and power law PSA kinetics represented 7.5% and 7.7%, respectively. Remaining fraction of analyzed OFTPs (40%) exhibited complex kinetics. Exponential PSA kinetics during the first OFTP was significantly associated with worse oncologic outcome. The estimated 10-year cancer-specific survival (CSS) was 46% for exponential versus 80% for nonexponential PSA kinetics patterns. The corresponding 10-year probability of castration-resistant prostate cancer (CRPC) was 69% and 31% for the two patterns, respectively. Limitations include retrospective design and mixed indications for IAD. CONCLUSION: PSA kinetic fitted with exponential pattern in approximately half of the OFTPs. First OFTP exponential PSA kinetic was associated with a shorter time to CRPC and worse CSS.

Assessing competence needs for doctors in the emergency department duty rosters: an observational study.

BACKGROUND: The purpose of our investigation is to analyze if emergency epidemiology is randomly variable or predictable. If emergency admissions show a predictable pattern, we can use it for multiple planning purposes, especially defining competence needs for duty roster personnel. METHOD: An observational study of consecutive emergency admissions at Haukeland University Hospital in Bergen over six years. We extracted the discharge diagnoses from our electronic patient record and sorted the patients by diagnoses and frequency. Data were loaded into a Jupyter notebook and presented in form of frequency diagrams. The study population, 213,801 patients, comprises all emergency admissions in need of secondary emergency care from the relevant specialities in the catchment area of our hospital in the western health region of Norway. Patients in need of tertiary care from the whole region are also included. RESULTS: Our analysis shows an annually reproducible distribution pattern regarding type and number of patients. The pattern adhere to an exponential curve that is stable from year to year. An exponential distribution pattern also applies when we sort patients according to the capital letters groups in the ICD 10 system. The same applies if patients are sorted adhering to primarily surgical or medical diagnoses. CONCLUSION: Analysis of the emergency epidemiology of all admitted emergency patients in a defined geographical area gives a solid basis for defining competence needs for duty roster work.