Caregiver Burden and Related Factors Among Caregivers of Patients with Myotonic Dystrophy Type 1.

BACKGROUND: Multi-systemic symptoms of varying severity in myotonic dystrophy type 1 (DM1) may pose difficulties in caregiving. However, the factors which affect their care burden are yet to be sufficiently understood. OBJECTIVE: We investigated care burden and its correlates among caregivers of patients with DM1. METHODS: General demographic information was obtained from patients with DM1, as well as Barthel index (ADL), body mass index, and genetic information. Patients completed SF-36v2 (health-related quality of life), CES-D (depressive symptoms), and ESS (daytime sleepiness) questionnaires. Caregivers reported their perception of patient's status through these questionnaires, and completed Zarit Caregiver Burden Interview (ZBI). Correlation analysis of these variables were performed, and regression analysis was utilized to assess the relationship between caregiver burden and other variables. RESULTS: Forty-three patient-caregiver dyads participated. Mean ZBI score was 20.7±17.4, and 32.6% reported a significant care burden. ZBI correlated with caregiver-reported CES-D, but not with patient-reported CES-D. Both patient-reported and caregiver-reported physical QoL of patients correlated with patient ADL. Multiple regression analysis revealed that the combination of caregiver-reported CES-D, caregiver-reported mental QoL, and genetic characteristics predicted caregiver burden. CONCLUSIONS: Caregiver burden was felt although patients were relatively well-functioning. Patients' and caregivers' assessment of patients' physical condition were similar. However, they did not agree on the evaluation of the patients' psychological state. Cognitive characteristic of the patients and the caregivers' perception of the patients' state may have affected the results. Future DM1 care strategies need to work on improvement of patient-caregiver communication and provide support for the caregiver's psychological health.

Health-related quality of life and its correlates in Japanese patients with myotonic dystrophy type 1.

PURPOSE: Myotonic dystrophy type 1 (DM1) is a common form of muscular dystrophy that presents with a variety of symptoms that can affect patients' quality of life (QoL). Despite the importance of clarifying patients' subjective experience in both physical and psychosocial aspects for improved symptom management, there is lack of evidence concerning QoL of patients with DM1 in Japan. PATIENTS AND METHODS: A cross-sectional study was performed with 51 DM1 patients who completed questionnaires that measured health-related QoL (HRQoL), depression, and daytime sleepiness. Activities of daily living, body mass index (BMI), and genetic information were also collected, together with general demographic information. Correlation analyses using these variables were performed. Furthermore, regression analysis was utilized to assess the relationship that HRQoL, depression, and daytime sleepiness scores have with other variables. RESULTS: Physical component summary (PCS) score was affected by the disease more than the mental component summary (MCS) score among study participants. Moderate correlation was observed between PCS and depression, PCS and Barthel index, and depression and daytime sleepiness. Regression analysis revealed that age, sex, cytosine-thymine-guanine repeats, and BMI did not predict the aforementioned dependent variables. CONCLUSION: DM1 symptoms influenced physical component scores more than mental component scores, although the state of physical wellness seemed to affect patients' mood. Explaining the QoL of these patients only using biologic and genetic characteristics was not sufficient. We conclude that social and psychological aspects of these patients' lives and the nature of adjustments made by patients due to DM1 to require further examination in order to improve the standard of care.

Molecular dynamics studies of the structural change in 1,3-diamino-2,4,6-trinitrobenzene (DATB) in the crystalline state under high pressure.

Molecular dynamics (MD) calculations were performed to reveal the effect of high pressure on the crystal of 1,3-diamino-2,4,6-trinitrobenzene (DATB). The coordinates of the individual atoms in the DATB crystal structure were obtained using X-ray diffraction analysis. The primary simulation cell consists of 54 molecules in a monoclinic cell, corresponding to 27 unit cells obtained by replicating the experimentally determined unit cell. The pressure dependence of intermolecular distance concerning hydrogen bonds in the DATB crystal was investigated in the range of 1 atm to 25.0 GPa by increasing the pressure at every 0.5 GPa. Intermolecular distances of the hydrogen bonds between the nitro and amino groups decrease with increasing pressure up to 25.0 GPa, except in the range of 7.5 to 8.5 GPa. A unique structural change in the DATB crystal occurred at approximately 7.5 GPa. Intermolecular distances began to remarkably increase at 7.5 GPa and kept increasing until 8.5 GPa. To clarify the origin of this strange behavior, we used the same pressure regions as those above to analyze the changes in the dihedral angles defined by the plane of the nitro or amino group and by the aromatic rings of hydrogen bonds. The results showed a strong correlation between the increment of the intermolecular distances and the changes in the dihedral angles for these groups. Moreover, when the pressure dependence of the crystal parameter was analyzed, it was found that the a-axis length did not change despite the change in the lengths of the other two axes. The direction of the a axis corresponds to the direction of intermolecular hydrogen bond networks in the crystal. The results of the present MD calculations explained our previous results for Raman spectra measurements. Further analysis showed that these hydrogen bonds play an important role in stabilizing the energy change of the crystal system.