ABSTRACT
Objective@#To investigate the status and influencing factors of disease uncertainty among caregivers of colorectal cancer patients receiving chemotherapy, so as to provide insights into psychological interventions among caregivers. @*Methods@#Caregivers of colorectal cancer patients hospitalized in Hunan Cancer Hospital, the Third Xiangya Hospital and the Second Xiangya Hospital for chemotherapy from March 2020 to December 2021 were recruited. Caregivers' demographics, health status, medical and nursing support and social support, as well as patients' demographics, frequency of chemotherapy and disease stage were collected using questionnaire surveys. Caregivers' disease uncertainty was evaluated using Chinese version of the Uncertainty in Illness Scale for Family Members, and factors affecting caregivers' disease uncertainty were identified using a multivariable linear regression model.@*Results@#A total of 318 caregivers were enrolled, including 115 men (36.16%) and 203 women (63.84%), with a mean age of (45.89±6.57) years, and there were 186 caregivers as patients' spouses (58.49%). The mean score of disease uncertainty was (86.65±10.82) points, and the scores of the unpredictability dimension, uncertainty dimension, complexity, and lack of information dimension were (3.21±0.35), (2.98±0.48), (2.84±0.49) and (2.36±0.59) points, respectively. There were 285 participants with a high level of disease uncertainty (89.62%), and multivariable linear regression analysis identified social support (β′=-0.199), medical and nursing support (β′=-0.118), patient's age (β′=-0.155) and stage Ⅲ and Ⅳ of colorectal cancer (β′=0.151) as factors affecting caregiver's disease uncertainty.@*Conclusion@#Caregivers of colorectal cancer patients with chemotherapy have a high level of disease uncertainty, which is affected by social support, medical and nursing support, patient's age and duration of disease.
ABSTRACT
Nitrile hydratase (NHase) has attracted considerable attention since it can efficiently catalyze the hydration of nitriles to valuable amides. However, the poor stability of NHase is one of the main drawbacks in the industrial application. In this study, we compared the structural difference between Fe-type and Co-type NHase and found that an extra α helix existed at the ß-subunit surface of Co-type NHase (defined as the ß-6th helix). Then, the effects of the ß-6th helix were investigated on the thermal stability and the catalytic kinetics of a Co-type NHase from Aurantimonas manganoxydans ATCC BAA-1229 (NHase1229). When the ß-6th helix was deleted or disrupted, the thermal stability of NHase1229 was reduced to 17.6 and 12.9% of that of wild NHase1229, respectively. Thus, the ß-6th helix is important for the thermal stability of Co-type NHase. Based on the structural characteristics of Co-type NHase, the ß-6th helix may be interacted with another helix at the α-subunit (defined as the α-2nd helix) by hydrophobic network just as a "magnetic suction buckle" on the enzyme surface to stabilize the binding of α- and ß-subunits. The ß-6th helix is located at the mouth of the substrate and product tunnel, so it plays crucial roles in catalytic process. Furthermore, the ß-6th helix in NHase1229 was swapped with a thermophilic NHase fragment from Pseudonocardia thermophila JCM3095 (NHase1229-Swap). The thermal stability of NHase1229-Swap was significantly improved, and the half-life was approximately 2.4-fold at 40 °C than that of the wild NHase1229. The knowledge is useful for improving the stability of NHases by restriction fragment swapping.
