Correlated receptor transport processes buffer single-cell heterogeneity.

Cells typically vary in their response to extracellular ligands. Receptor transport processes modulate ligand-receptor induced signal transduction and impact the variability in cellular responses. Here, we quantitatively characterized cellular variability in erythropoietin receptor (EpoR) trafficking at the single-cell level based on live-cell imaging and mathematical modeling. Using ensembles of single-cell mathematical models reduced parameter uncertainties and showed that rapid EpoR turnover, transport of internalized EpoR back to the plasma membrane, and degradation of Epo-EpoR complexes were essential for receptor trafficking. EpoR trafficking dynamics in adherent H838 lung cancer cells closely resembled the dynamics previously characterized by mathematical modeling in suspension cells, indicating that dynamic properties of the EpoR system are widely conserved. Receptor transport processes differed by one order of magnitude between individual cells. However, the concentration of activated Epo-EpoR complexes was less variable due to the correlated kinetics of opposing transport processes acting as a buffering system.

Gender aspects of parents' needs of schizophrenia patients.

BACKGROUND: Most studies about the problems and needs of schizophrenia carers included only one care-giving relative, usually the patients' mothers. METHODS: 101 mothers and fathers of the same patients suffering from schizophrenia were included into this study. Their needs were assessed by means of the "Carers' Needs Assessment for Schizophrenia". RESULTS: Mothers reported significantly more often problems than fathers concerning stress due to earlier life events and burn-out. Mothers needed interventions such as individual psychoeducation or family counselling more than twice as often as fathers. Overall, mothers reported higher numbers of problems and needs for intervention than fathers. The number of mothers' problems was predicted by not living with a partner and by a shorter duration of the patients' illness. The number of mothers' needs was predicted by more psychiatric symptoms, not living with a partner and a shorter duration of the patients' illness. Among fathers we could not identify any predictors, neither for the number of problems nor for the number of needs. CONCLUSIONS: Fathers and mothers often report problems and frequently need professional support. Overall, mothers exhibited more problems and needs for interventions than fathers. The differences between mothers and fathers indicate the importance of considering the carer's gender in clinical work.

[Are there gender-specific differences between mothers and fathers caring for a schizophrenia patient?]. / Gibt es geschlechtsspezifische Unterschiede in der elterlichen Betreuung von Schizophrenie-Kranken?

OBJECTIVE: The purpose of this study was to investigate differences between mothers and fathers of patients with schizophrenia or schizoaffective disorders concerning the time spent with the patients as well as other aspects of caring. METHODS: 101 mothers and 101 fathers of the same patients suffering from schizophrenia or schizoaffective disorders according to ICD-10 were investigated. RESULTS: The mean time spent in personal (i.e. face-to-face) or telephone contact with patients was significantly higher for mothers than for fathers. About the half of the mothers spent more time with the patients than the fathers, while 12% of fathers spent more time than the mothers. Among 40% of patients, mothers and fathers spent an equal amount of time for personal or telephone contact with the patients. Concerning other aspects of caring (legal representative of the patient, payment for patient's costs, caring for the patient's household) we could not find any differences between mothers and fathers. CONCLUSIONS: Concerning several aspects we could not confirm that mothers are more involved into the patients' care than the fathers. These findings are in contrast to the usual assumptions about familial caregivers based on the traditional gender-specific role models.

[Minor relatives of schizophrenia patients: burden and needs]. / Minderjährige Angehörige von Schizophrenie-Kranken: Belastungen und Unterstützungsbedarf.

OBJECTIVES: The aim of the present study was to investigate the burden of minor relatives of schizophrenia patients and of the needs for support for the relatives. METHODS: 135 relatives of patients with schizophrenia or schizoaffective disorders were assessed by using the "Involvement Evaluation Questionnaire" and the "Carers' Needs Assessment for Schizophrenia". RESULTS: 24.4% of the total sample (N=33) had minor (i.e. below 18 years) siblings (N=18) or children (N=15). If the patient had minor siblings, almost the half of the adult relatives reported moderate or severe problems. However, among those patients who had to take care for minor children, only a fifth reported moderate or severe problems. Among the patients' offsprings being under the age of 16 behavioural disturbances, reduced appetite and other consequences of the disease were reported frequently. CONCLUSIONS: These results indicate that patients with schizophrenia or schizoaffective disorders often have minor relatives in their family frequently suffering from marked burden.

The importance of statistical modelling in clinical research : Comparing multidimensional Rasch-, structural equation and linear regression models for analyzing the depression of relatives of psychiatric patients.

BACKGROUND: Various studies have shown that caregiving relatives of schizophrenic patients are at risk of suffering from depression. These studies differ with respect to the applied statistical methods, which could influence the findings. Therefore, the present study analyzes to which extent different methods may cause differing results. METHODS: The present study contrasts by means of one data set the results of three different modelling approaches, Rasch Modelling (RM), Structural Equation Modelling (SEM), and Linear Regression Modelling (LRM). RESULTS: The results of the three models varied considerably, reflecting the different assumptions of the respective models. CONCLUSIONS: Latent trait models (i. e., RM and SEM) generally provide more convincing results by correcting for measurement error and the RM specifically proves superior for it treats ordered categorical data most adequately.

The Carers' Needs Assessment for Dementia (CNA-D): development, validity and reliability.

BACKGROUND: A variety of interventions are available to support the caregivers of dementia patients. For the purposes of service planning, we developed an instrument to assess the needs of these caregivers and to determine whether needs are met. The reliability and validity of this new instrument was also investigated. METHODS: The development of the Carers' Needs Assessment for Dementia (CNA-D), was based on in-depth interviews and a focus group. The combined inter-rater and test-retest reliability was investigated among 45 dementia caregivers. Correlations of the CNA-D with the Zarit Burden Inventory were used to analyze concurrent validity. Content validity was investigated by performing a separate survey among 40 caregivers and 40 professionals. RESULTS: The CNA-D is a semi-structured research interview including 18 problem areas. For each problem area, the CNA-D offers several possible interventions. The relevance of the problem areas and the interventions (content validity) was confirmed by most of the study participants. Significant positive associations were found between the total score of the Zarit Burden Inventory and the number of problems and the number of unmet needs according to the CNA-D. The agreement between the interviewers was "excellent" (kappa above 0.75) in 73.7% of the problem areas and in 69.9% of the interventions. CONCLUSIONS: The CNA-D is a valid and reliable instrument for comprehensively assessing the needs of dementia caregivers.