A path analysis investigation into menopausal osteoporosis, sarcopenia risk, and their impact on sleep quality, depressive symptoms and quality of life.

PURPOSE: The objective was to investigate the relationships among disease characteristics, sarcopenia risk, bone function, sleep quality, depressive symptoms, and health-related quality of life in menopausal women. Additionally, we also examined the potential mediating role of coping in the relationship between these factors and health outcomes for individuals with osteoporosis. METHODS: In a cross-sectional approach, 201 participants were referred by a physician from the Family Medicine Department during their outpatient visits at a general hospital in Southern Taiwan. Data collection involved structured one-on-one interviews, and the analysis included descriptive and inferential statistics, along with a structural equation modeling. RESULTS: The participants' bone function was strongly positively related to coping, physical and mental quality of life (QOL), and negatively related to sleep quality and depressive symptoms. The duration of osteoporosis was positively related to pain, sarcopenia risk, sleep quality, but negatively related to bone function, physical and mental QOL. This structural framework explains 36% of the variance in depressive symptoms, 25% in sleep disturbances, 54% in mental QOL, and 72% in physical QOL. The best-fit structural equation modeling showed that physical function, exercise, sarcopenia, pain, and coping were significant predictors of depressive symptoms, with coping acting as a mediator in these relationships. CONCLUSION: Individuals who employed more active coping strategies exhibited fewer depressive symptoms, better sleep quality, and superior physical and mental QOL. Further, individuals with osteoporosis had lower pain levels, less sarcopenia risk, and higher engaged in exercise presentation improved physical and mental QOL. Future longitudinal research holds the promise of providing deeper insights into these complex relationships.

Sleep disturbances, glycaemic control, stress, and coping among diabetic patients: A structural equation modelling approach.

BACKGROUND: Sleep disturbances are more prevalent in diabetic patients than in the general population and may consequently be comorbid with hyperglycaemia. OBJECTIVE: The two study aims were to (1) verify the factors associated with sleep disturbances and glycaemic control and (2) further understand the mediation effects of coping and social support in the relationship among stress, sleep disturbances, and glycaemic control. METHODS: A cross-sectional study design was used. Data were collected at two metabolic clinics in southern Taiwan. The study recruited 210 patients with type II diabetes mellitus who were aged 20 years or above. Demographic information and data on stress, coping, social support, sleep disturbances, and glycaemic control were collected. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality, and PSQI scores >5 were considered to indicate sleep disturbances. Structural equation modelling (SEM) approaches were employed to analyse the path association for sleep disturbances in diabetic patients. RESULTS: The mean age of the 210 participants was 61.43 (standard deviation, SD 11.41) years old, and 71.9 % reported sleep disturbances. The final path model had acceptable model fit indices. Stress perception was divided into stress perceived positively and negatively. Stress perceived positively was associated with coping (ß = 0.46, p < .01) and social support (ß = 0.31, p < .01), whereas stress perceived negatively was significantly associated with sleep disturbances (ß = 0.40, p < .001). CONCLUSIONS: The study shows that sleep quality is essential to glycaemic control, and stress perceived negatively might play a critical role to sleep quality.

Application of Grey Relational Analysis to Predict Dementia Tendency by Cognitive Function, Sleep Disturbances, and Health Conditions of Diabetic Patients.

Background: The number of elderly diabetic patients has been increasing recently, and these patients have a higher morbidity of dementia than those without diabetes. Diabetes is associated with an increased risk for the development of dementia in elderly individuals, which is a serious health problem. Objectives: The primary aim was to examine whether diabetes is a risk factor for dementia among elderly individuals. The secondary aim was to apply grey theory to integrate the results and how they relate to cognitive impairments in elderly diabetic patients and to predict which participants are at high risk of developing dementia. Methods: Two hundred and twenty patients aged 50 years or older who were diagnosed with diabetes mellitus were recruited. Information on demographics, disease characteristics, activities of daily living, Mini Mental State Examination, sleep quality, depressive symptoms, and health-related quality of life was collected via questionnaires. The grey relational analysis approach was applied to evaluate the relationship between the results and health outcomes. Results: A total of 13.6% of participants had cognitive disturbances, of whom 1.4% had severe cognitive dysfunction. However, with regard to sleep disorders, 56.4% had sleep disturbances of varying degrees from light to severe. Further investigation is needed to address this problem. A higher prevalence of sleep disturbances among diabetic patients translates to a higher degree of depressive symptoms and a worse physical and mental health-related quality of life. Furthermore, based on the grey relational analysis, the grey relation coefficient varies from 0.6217~0.7540. Among the subjects, Participant 101 had the highest value, suggesting a need for immediate medical care. In this study, we observed that 20% of the total participants, for whom the grey relation coefficient was 0.6730, needed further and immediate medical care.

Cognitive Behavioral Therapy plus Coping Management for Depression and Anxiety on Improving Sleep Quality and Health for Patients with Breast Cancer.

Cancer-related treatments may lead to side effects that undermine a patients' quality of life (QOL). Although cognitive behavioral therapy plus coping management (CBTM) may appear to improve health-related QOL in cancer patients, limited documentation exists on the effectiveness of psychosocial interventions for patients with breast cancer (BC) during recovery. The purpose of this study was to examine the effectiveness of CBTM for sleep quality, anxiety, depression, and health among patients with BC. An experimental study was conducted to assess the efficacy of a CBTM intervention (experimental group = 36, control group = 34). The experimental group received a 12-week CBTM intervention focused on their identity, challenges, the replacement of dysfunctional beliefs, coping skills, relaxation, and rehabilitation exercises, while the control group received usual care. The follow-up evaluations were performed immediately after the intervention (T1), and at one (T2) and three months (T3). The generalized estimating equation (GEE) model showed significant effects from the CBTM intervention over time. The experimental group showed significant improvement in sleep quality, anxiety and depressive symptoms, and significant increases in their mental and physical QOL from baseline, T1, T2, and T3-except for the mental and physical QOL showing no significant change at T3-while the control group receiving usual care showed no changes over time. The results suggest that CBTM increases sleep quality, reduces anxiety and depressive symptoms, and enhances health-related QOL for participants. CBTM is efficacious and can be provided by nurses to enhance patients' coping skills and consequently improve their QOL.

Nurses' knowledge, attitude, and competence regarding palliative and end-of-life care: a path analysis.

BACKGROUND: Nurses' knowledge regarding palliative and end-of-life (EOL) care has been documented, but the competence of nurses in Taiwan has not been deeply analyzed and may affect the use of EOL care. PURPOSE: We aimed to (1) assess the palliative care knowledge, competence and attitude of nurses in a general hospital and (2) examine the paths connecting nurses' demographic characteristics, previous experiences, knowledge, competence, and attitude. METHOD: A correlational, cross-sectional survey design was implemented to recruit 682 eligible nurses. The questionnaires included demographic information and palliative and EOL care knowledge, attitude, and competence scales. Path analysis was employed for statistical analysis using structural equation modeling. RESULTS: Overall, 76% of the questions assessing palliative and hospice knowledge were answered correctly. Nurses' palliative attitudes were divided into "positive perception" and "negative perception". "Positive perception" was highly correlated with competence (r = 0.48, p < 0.001), but "negative perception" was not significantly correlated with competence (r = -0.07, p = 0.25). "Positive perception" (ß =  -0.01, p = 0.84) and competence (ß =  0.02, p = 0.80) were not related to palliative knowledge. "Negative perception", however, was negatively associated with palliative knowledge (ß =  -0.20, p < 0.01). CONCLUSIONS: This study suggests continuing education to decrease nurses' "negative perception" attitude regarding the provision of information to patients and families to provide better palliative and EOL care. IMPLICATIONS FOR PRACTICE: Nurses' attitudes and competences with respect to palliative care and EOL care are critical. Areas for further research and advanced palliative and EOL care-related education and training are suggested and may be applied in future clinical interventions.

Psychometric and Linguistic Evaluation of a Coping Scale for Breast Cancer Survivors in Taiwan.

BACKGROUND: Coping strategies are essential in dealing with threatening situations or difficulties for better psychological adjustments and quality of life. A short-form modified Ways of Coping Questionnaire (MWCQ) would be useful to quickly assess the coping strategies used by breast cancer survivors. OBJECTIVES: The aim of this study was to evaluate the psychometric properties of a Chinese version of a brief version of the MWCQ in breast cancer survivors. METHODS: A methodological, cross-sectional design was used in this study. The study has internal consistency reliability, face/content, construct, and convergent/divergent validity. Factor analysis and confirmatory factor analysis were used to examine the psychometric properties of the MWCQ-brief in a convenience sample of 207 women with breast cancer from 2 general hospitals in Taiwan. RESULTS: From the initial 35-item coping scale, factor analysis results supported a 24-item questionnaire, and the following 4 factors were extracted: effective coping, optimistic coping, unpractical coping, and escape coping. Confirmatory factor analysis results revealed an 18-item questionnaire with 3 factors extracted: active coping, avoidance coping, and minimizing the situation. CONCLUSIONS: The 24- and 18-item MWCQ-brief versions demonstrate fair psychometric properties to measure adaptability among women with breast cancer in Taiwan. This scale is simple but contains 4 or 3 concepts for coping that can be appropriately used to assess underlying states of adaptation in women with breast cancer. IMPLICATIONS FOR PRACTICE: The MWCQ-brief is a valid and reliable tool to understand the adaptability states of female breast cancer survivors by exploring reactions to the disease. Healthcare professionals can provide appropriate psychosocial interventions based on assessment results.

The main factors affecting Taiwan's economic growth rate via dynamic grey relational analysis.

Ever since the grey system theory was proposed about 40 years ago, its characteristics such as small samples, few data, and uncertainty have been used for study in the literature with increasingly wider scope. Recent studies on grey relation analysis have included static data analyses, and most of them have adopted initial values with only a relational order. Under the same study conditions, if different data preprocessing methods are used, then the relational order will be ranked differently. This study took Taiwan as the object to explore seven economic indices (birth rate (%), Taiwan's total population (thousand people), unemployment rate (%), income per capita (USD), weighted average interest rate on deposits (%), Consumer Price Index (CPI), and national income (NI)) and how they affect the economic growth rate. The traditional static grey relational analysis treated the collected data with taking consideration of time effect which is irrational under some circumstance. An innovative dynamic grey relational analysis was carried out by shifting the raw data due to the time leading or lagging effect which is a mean to improve the capability of traditional grey relational analysis. The differences in analyses between static grey relational analysis and dynamic grey relational analysis via different data preprocessing methods were further discussed, finding that different data preprocessing methods generated a new set of relational orders through the latter. Finally, the prosperity index was used to identify the effects of all factors on economic growth (leading, synchronization, and lagging indices).

Resilience and coping styles as predictors of health outcomes in breast cancer patients: A structural equation modelling analysis.

INTRODUCTION: Resilience has been associated with psychological adaptation to many threatening life events, but previous studies have rarely analysed the integrated relationships among demographic and disease characteristics and various health outcomes in Taiwan. This study examined the associations among demographic factors, disease characteristics, resilience, coping styles and adverse health outcomes, including anxiety and depressive symptoms and sleep disorders. METHODS: A descriptive, cross-sectional study design was used. Data from a convenience sample of 175 patients with breast cancer aged 20 years or older were collected using a self-reported questionnaire. A structural equation modelling approach was applied to examine the relationships among the variables. RESULTS: The results showed that greater resilience was related to fewer depressive symptoms, lower anxiety levels and better sleep quality. All three coping styles, including active coping, minimising the situation and avoidance coping, were negatively correlated with depressive symptoms, but only active coping was significantly correlated with sleep quality. Resilience had a direct effect on depressive symptoms, anxiety and sleep disorders. Furthermore, a mediating effect of resilience was observed on the relationship between marital satisfaction and depressive symptoms. CONCLUSION: Resilience can strengthen breast cancer-related adaptation. Additionally, breast cancer survivors who used mainly the active and minimising coping styles tended to experience fewer depressive symptoms.

Social support as a mediator between sleep disturbances, depressive symptoms, and health-related quality of life in patients undergoing hemodialysis.

BACKGROUND: The hemodialysis regimen is an inevitable and mandatory treatment for patients with end-stage renal disease (ESRD). During the dialysis journey, patients may experience maladaptation in terms of sleep disturbances, depressive symptoms, and reduced health-related quality of life (HRQOL). Psychosocial resources such as social support may have beneficial influences on health outcomes, but studies have rarely analyzed the integrated relationships among risk factors which include pain, sleep disturbances, duration since diagnosis and various health outcomes in Taiwan. This study aimed to bridge this gap by investigating the relationships among related risk factors, social support, sleep disturbances, depressive symptoms, and HRQOL, which is composed of physical quality of life (PQOL) and mental quality of life (MQOL), in ESRD patients. METHOD: A correlational design was used, and 178 patients aged 20 years or older were recruited via convenience sample. The relationships among the risk factors, the mediators, depressive symptoms, PQOL, and MQOL were analyzed using structural equation modeling. RESULTS: The findings showed that more than 70% of the participants reported poor sleep quality, and 32% reported depressive symptoms. When participants had greater pain and more sleep disorders, they were more likely to be depressed. When participants had more appraisal support; they had better PQOL and fewer depressive symptoms. Overall, the structural equation model explained 31.8% of the variance in self-reported depressive symptoms, 29.4% of the variance in PQOL, and 5.7% of the variance in MQOL. Moreover, appraisal support enhanced PQOL and reduced depressive symptoms by exerting its two mediating effects on sleep disturbances. CONCLUSION: Our findings indicate that patients with ESRD who have more social support have better PQOL and MQOL and fewer depressive symptoms than those with less social support.

Relationships among personality, coping, and concurrent health-related quality of life in women with breast cancer.

BACKGROUND: Theory has suggested that personality plays an important role related to health behavior and results in health outcomes, but inconsistent with the findings exist. Moreover, limited research has focused on style of coping with personality traits and health-related quality of life (HRQOL) for patients with breast cancer. We tested how ways of coping and personality traits are associated with HRQOL in patients with breast cancer, after controlling for age, education, disease severity, and sleep disorders. METHODS: In a cross-sectional study of 207 patients with breast cancer, they completed a set of questionnaires at two general hospitals. The measures used were demographic and individual characteristics, personality traits, ways of coping, and health surveys. We used correlations and hierarchical regressions to determine all relationships among factors, sleep disorders, personality, coping, and HRQOL. RESULTS: Most participants were reported as having stage II (77, 37.2%) breast cancer. About 60% patients with breast cancer have poor sleep and sleep disorders having a negative association with HRQOL. Participants using more active coping, with lower neuroticism, and higher agreeableness traits are more likely to have a better physical quality of life (PQOL). In the PQOL regression model, clinical conditions (duration since cancer diagnosis; sleep disorders) and two personality traits (neuroticism and agreeableness) significantly explained 23% of variance. Moreover, fewer sleep disorders and two personality traits (neuroticism and conscientiousness) significantly explained 31% of variance in the mental quality-of-life (MQOL) regression model. CONCLUSIONS: A high prevalence of sleep disorders for patients with breast cancer has occurred and sleep disorders were negatively associated with PQOL and MQOL. In addition, neuroticism was positively related to sleep disorders and could be relevant to psycho-educational interventions.

Robotic mitral valve replacements with bioprosthetic valves in 52 patients: experience from a tertiary referral hospital.

OBJECTIVES: Robotic mitral valve replacement (MVR) emerged in the late 1990s as an alternative approach to conventional sternotomy. With the increased use of bioprosthetic valves worldwide and strong patient desire for minimally invasive procedures, the safety and feasibility of robotic MVRs with bioprosthetic valves require investigation. METHODS: Between January 2013 and May 2017, 52 consecutive patients underwent robotic MVRs using the da Vinci Si surgical system (Intuitive Surgical Inc., Sunnyvale, CA, USA). Their mean age was 55.1 ± 13.8 years, and mean EuroSCORE II was 2.25% ± 1.25%. Among the enrolled patients, 32 (61.5%) patients presented with preoperative atrial fibrillation, 6 (11.5%) patients had experienced embolic stroke and 5 (9.6%) patients had undergone previous cardiac surgery. The operations were performed using cardiopulmonary bypass (CPB) under an arrested heart status. RESULTS: Five porcine valves and 47 bovine valves were implanted. A total of 38 (73.1%) patients received concomitant cardiac procedures, including 26 Cox-maze IV procedures, 12 tricuspid valve repairs and 5 atrial septal defect repairs. The mean aortic cross-clamp and CPB times were 141.3 ± 34.3 min and 217.1 ± 42.0 min, respectively. There was no operative mortality. During the mean follow-up of 29 ± 15 months, no prosthesis degeneration was noted. The average left atrial dimension exhibited a significant decrease from 51.4 ± 11.5 mm to 42.6 ± 10.1 mm. CONCLUSIONS: Robotic MVR with bioprosthetic valves is safe, feasible and reproducible. Mid-term results are encouraging. Both aortic cross-clamp and CPB times can be improved with experience.

Depressive Symptoms and Health-Related Quality of Life Among Prostate Cancer Survivors.

BACKGROUND: Prostate cancer is a global health problem; its incidence is on the rise in Chinese and usually fraught with both physical and psychological symptomatology. OBJECTIVE: The aim of this study is to explore the relationships among demographic and disease characteristics, resourcefulness, depressive symptoms, and health related quality of life (HRQOL). METHODS: A descriptive, correlational design was used. A total of 200 individuals with prostate cancer were recruited. The participants completed a self-report regarding their depressive symptoms and HRQOL. Using a structural equation modeling approach, all relationships among the factors, mediators, depressive symptoms, and HRQOL were analyzed. RESULTS: The more resourcefulness that participants perceived, the more likely they were to report better HRQOL. The best-fitted structural equation model included individual demographics and disease characteristics and resourcefulness as significant predictors of HRQOL. Moreover, this structural model explained 72%, 76%, and 57% of the variance in physical quality of life, mental quality of life, and depressive symptoms, respectively. In addition, resourcefulness had a positive mediating effect on increasing the physical and mental quality of life and decreasing the depressive symptoms for patients with prostate cancer. CONCLUSIONS: Resourcefulness helps patients with prostate cancer build a positive attitude and that it is crucial for enhancing the HRQOL of patients. By using the proper resourcefulness strategy, that is, either personal (self-help) or social (help-seeking), nursing professionals can substantially contribute to enhancing the HRQOL for patients with PC. IMPLICATIONS FOR PRACTICE: Knowledge of risk factors for HRQOL would be useful for nursing professional in detecting health problems and treatment options.

Depression and Health-Related Quality of Life and Their Association With Resourcefulness in Survivors of Prostate Cancer.

OBJECTIVE: This study aimed to identify the determinants of depressive symptoms (DSs) and health-related quality of life (HRQOL) in survivors of prostate cancer (PC). METHODS: This study used a descriptive, correlational design to assess a sample of 133 individuals with PC. The participants were face-to-face interviewed to collect demographic data and disease characteristics, assess self-control schedule, and survey health status. Correlation analysis, Student's t-test, ANOVA, and regression analysis were applied. RESULTS: Over half the patients had depressive symptoms, and 96.1% had erectile dysfunction. Lack of resourcefulness was found to decrease PC-specific quality of life (PCQOL) and physical quality of life (PQOL). The participants who were more resourceful showed a better mental quality of life (MQOL) and PQOL (r=0.53**; r=0.41**) and fewer DSs (r=-0.52**). Most participants were stage II and IV, and there were significantly different effects on PQOL and MQOL related to cancer stage. Regarding the different outcomes of various therapies, the findings suggested that survivors of PC who underwent radical prostatectomy were more likely to have a better MQOL than those who underwent other treatments. In addition, resourcefulness had mediating effects on pain, PQOL/MQOL, and DSs in the patients with PC. CONCLUSIONS: Good mental health and resourcefulness can help patients with PC reduce pain and enhance positive thinking and may augment PQOL and MQOL.

Robotic totally endoscopic coronary artery bypass for isolated ostial stenosis of the left coronary artery.

Isolated ostial stenosis (IOS) is a rare disease that encroaches on aorto-coronary junction of uncertain etiology. All distal coronary vessels present normally. IOS occurs predominantly in premenopausal young women with few risk factors for atherosclerotic disease. Here, we report a 40-year-old woman who had experienced crescendo angina for 4 months. Surgical revascularization was achieved by robotic totally endoscopic coronary artery bypass (TECAB) with left internal thoracic artery (LITA) graft. She resumed her daily tasks without difficulties 1 week after the operation. Postoperative computed tomographic angiography disclosed good opacification of the LITA graft and distal runoff. Robotic TECAB is a potentially feasible alternative for IOS patients, particularly in premenopausal young woman, with obvious benefits of cosmetic appearance and speedy recovery.

Effects of Resourcefulness on Sleep Disturbances, Anxiety, and Depressive symptoms in Family Members of Intensive Care Unit Patients.

The study aimed to investigate the relationships among psychological distresses, resourcefulness, sleep disturbances, anxiety and depressive symptoms in family members of intensive care unit (ICU) patients. A cross-sectional, descriptive correlational design was employed. Using structural equation modeling (SEM) approach, relationships among factors, mediators, and outcomes were analyzed. The SEM explained 59% of the variances in depressive symptoms and 36% in anxiety. Family members with greater learned resourcefulness had fewer sleep disturbances, depressive and anxiety symptoms. Nursing professionals need to detect psychiatric disease of family members and must be especially vigilant with people who have low resourcefulness and sleep disturbances.

Risk Factors and Coping Style Affect Health Outcomes in Adults With Type 2 Diabetes.

OBJECTIVE: Most psychosocial interventions among individuals with Type 2 diabetes mellitus (T2DM) target depressive symptoms (DSs) rather than causal antecedents that lead to DSs or affect health-related quality of life (HrQoL). This research investigated a conceptual model of the effects of risk factors and coping styles on HrQoL and DSs in patients with T2DM. METHOD: A descriptive, correlational design was used with a convenience sample of 241 adults with T2DM aged ≥ 20 years recruited from a hospital metabolic outpatient department. Data were collected using a demographic questionnaire, the modified Ways of Coping Checklist, the Center for Epidemiological Studies Depression Scale, the Short Form 36 Health Survey, and physiological examination. HbA1C was collected from participants' medical records. Structural equation modeling techniques were used to analyze relationships among risk factors, mediators, and HrQoL. RESULTS: Younger age, more education, and longer duration of diabetes predicted better physical quality of life. Duration of diabetes and three coping styles predicted DSs. Longer duration of diabetes and lower fasting glucose predicted better mental quality of life. Three coping styles acted as mediators between risk factors and health, that is, active and minimizing styles promoted positive outcomes, while avoidance promoted negative outcomes. CONCLUSIONS: This integrated model provides a holistic picture of how risk factors and coping style influence HrQoL and DSs in individuals with T2DM. Nurses could use active coping strategies in cognitive behavioral therapy to enhance glycemic control in patients with T2DM.

Effects of motivational enhancement therapy plus cognitive behaviour therapy on depressive symptoms and health-related quality of life in adults with type II diabetes mellitus: a randomised controlled trial.

OBJECTIVE: This paper evaluates the effectiveness of motivational enhancement therapy plus cognitive behavioural therapy on depressive symptoms, glycosylated haemoglobin, fasting glucose, body mass index (BMI), and health-related quality of life in type II diabetes patients. METHODS: A controlled trial was conducted to compare patients who received the behavioural intervention with untreated controls on measures of health outcomes. A total of 31 intervention group participants and 30 controls were selected from patients that met the inclusion criteria from a hospital-based endocrinology outpatient department. The outcome measures including depressive symptoms, glycosylated haemoglobin, fasting glucose, BMI, and both physical and mental quality of life were collected before (T1), after (T2), and after 90 days (T3) following the intervention. RESULTS: The experimental group showed a significant reduction in glycosylated haemoglobin, fasting glucose, and depressive symptoms and a significant increase in physical quality of life and mental quality of life at T2 and T3, while patients in the control group with usual care showed no changes over time. CONCLUSION: The behavioural intervention facilitated a significant improvement in psychological adjustment and glycemic control, thus strengthening diabetes control skills and leading to healthy outcomes. It is feasible that nurses and psychiatrists can deliver the behavioural intervention for diabetes patients to decrease their depressive symptoms. Sharing discussion and problem-solving experiences is particularly helpful method for self-control, and these will be beneficially influential on further research.

Structure of human POFUT2: insights into thrombospondin type 1 repeat fold and O-fucosylation.

Protein O-fucosylation is a post-translational modification found on serine/threonine residues of thrombospondin type 1 repeats (TSR). The fucose transfer is catalysed by the protein O-fucosyltransferase 2 (POFUT2) and >40 human proteins contain the TSR consensus sequence for POFUT2-dependent fucosylation. To better understand O-fucosylation on TSR, we carried out a structural and functional analysis of human POFUT2 and its TSR substrate. Crystal structures of POFUT2 reveal a variation of the classical GT-B fold and identify sugar donor and TSR acceptor binding sites. Structural findings are correlated with steady-state kinetic measurements of wild-type and mutant POFUT2 and TSR and give insight into the catalytic mechanism and substrate specificity. By using an artificial mini-TSR substrate, we show that specificity is not primarily encoded in the TSR protein sequence but rather in the unusual 3D structure of a small part of the TSR. Our findings uncover that recognition of distinct conserved 3D fold motifs can be used as a mechanism to achieve substrate specificity by enzymes modifying completely folded proteins of very wide sequence diversity and biological function.

Enhanced expression of beta 3-galactosyltransferase 5 activity is sufficient to induce in vivo synthesis of extended type 1 chains on lactosylceramides of selected human colonic carcinoma cell lines.

In general, an elevated expression of beta 3-galactosyltransferase (beta 3GalT) activity contributed by beta 3GalT5 correlates well with increased biosynthesis and expression of type 1 chain (Gal beta 1-3GlcNAc beta 1-) derivatives such as Lewis A and sialyl Lewis A, which are mostly recognized as terminal epitopes and not further extended. Most known beta 3-N-acetylglucosaminyltransferases show a higher activity toward extending type 2 chain (Gal beta 1-4GlcNAc beta 1-), and an over-expression of beta 3GalT5 could suppress the formation of the type 2 chain poly-N-acetyllactosaminoglycans. The potential of extending instead the predominant type 1 chain termini synthesized under such circumstances was, however, not investigated, partly due to technical difficulty in unambiguous identification of extended type 1 chains. Using an advanced mass spectrometry-based glycomic mapping and glycan sequencing approach, we show here that type 1 chains carried on the lacto-series glycosphingolipids of colonic carcinoma cells can be extended when the endogenous beta 3GalT activity relative to competing beta 4GalT activity, as defined against a common GlcNAc beta 1-3Gal beta 1-4Glc acceptor, is sufficiently high, as found in Colo205 and SW1116, but not in DLD-1 cells. In support of this positive correlation, the lacto-series glycosphingolipids isolated from stably transfected DLD-1 clones over-expressing beta 3GalT5 were shown to comprise fucosylated dimeric type 1 chains, whereas a mock transfectant and the DLD-1 parent carried only fucosylated dimeric type 2 chains on their lactosylceramides. It suggests that while the natural expression of extended type 1 chain is likely to be determined by many contributing factors including the relative amounts of competing glycosyltransferases and the UDP-Gal level, the enhanced expression of beta 3GalT5 is sufficient to promote in vivo extension of type 1 chains by furnishing a significantly higher amount of type 1 chain precursors relative to competing type 2 chains.