Pilot test of a learned resourcefulness program for older family caregivers in Taiwan.

Learned resourcefulness, a theory-based education intervention, can be applied to provide strategies to improve the health status and reduce caregiver burden for older family caregivers. We developed a culturally relevant SOURCE program and designed a pilot study to its effect and feasibility for older family caregivers living in Taiwan. Using a quasi-experimental study with one-group, pre-test and post-test design, we recruited a convenience sample of 30 older family caregivers who received home-care services from a regional hospital in southern Taiwan. The older family caregivers participated in and completed the four-week SOURCE program. Effectiveness and feasibility data were collected after the completion of the program. Results indicated that the SOURCE program significantly improved caregiving burden (t = 3.05, p = .005) and revealed that the program was helpful and useful to older family caregivers. The next step will be to use the SOURCE program with more older family caregivers.

Effects of ketoconazole, voriconazole, and itraconazole on the pharmacokinetics of apatinib in rats.

We investigated the effect of azole antifungal drugs (ketoconazole, voriconazole, and itraconazole) on the pharmacokinetics of apatinib in rats. The rats in ketoconazole, voriconazole, and itraconazole groups received single-dose apatinib 30 mg/kg after the oral administration of ketoconazole, voriconazole, and itraconazole, respectively. Co-administration of ketoconazole or voriconazole significantly increased the apatinib Cmax and AUC(0-t) and decreased the clearance. Co-administration of itraconazole did not significantly affect the pharmacokinetics parameters of apatinib. It could be concluded that both ketoconazole and voriconazole significantly increase the exposure of apatinib, and affect the pharmacokinetics of apatinib in rat. Apatinib can be co-administered with itraconazole, but ketoconazole and voriconazole should be avoided if possible or be underwent therapeutic drug monitoring of apatinib. A further clinical study should be conducted to investigate the inhibitory effect of azole antifungal drugs on the apatinib plasma concentration.

Flux balance analysis predicts Warburg-like effects of mouse hepatocyte deficient in miR-122a.

The liver is a vital organ involving in various major metabolic functions in human body. MicroRNA-122 (miR-122) plays an important role in the regulation of liver metabolism, but its intrinsic physiological functions require further clarification. This study integrated the genome-scale metabolic model of hepatocytes and mouse experimental data with germline deletion of Mir122a (Mir122a-/-) to infer Warburg-like effects. Elevated expression of MiR-122a target genes in Mir122a-/-mice, especially those encoding for metabolic enzymes, was applied to analyze the flux distributions of the genome-scale metabolic model in normal and deficient states. By definition of the similarity ratio, we compared the flux fold change of the genome-scale metabolic model computational results and metabolomic profiling data measured through a liquid-chromatography with mass spectrometer, respectively, for hepatocytes of 2-month-old mice in normal and deficient states. The Ddc gene demonstrated the highest similarity ratio of 95% to the biological hypothesis of the Warburg effect, and similarity of 75% to the experimental observation. We also used 2, 6, and 11 months of mir-122 knockout mice liver cell to examined the expression pattern of DDC in the knockout mice livers to show upregulated profiles of DDC from the data. Furthermore, through a bioinformatics (LINCS program) prediction, BTK inhibitors and withaferin A could downregulate DDC expression, suggesting that such drugs could potentially alter the early events of metabolomics of liver cancer cells.

Creating a conceptual model for family caregivers of older adults intervention research: A narrative review of learned resourcefulness, resourcefulness, and the transtheoretical model.

Providing and maintaining optimal care is challenging for older family caregivers who are caring for disabled older adults. Learned Resourcefulness can facilitate family caregivers' self-help strategies, and Resourcefulness can facilitate help-seeking from others. However, little is known about how older family caregivers can effectively maintain and adapt self-help and help-seeking strategies over time, especially as the dynamic nature of caregiving for disabled older adults demands change. To this end, the Transtheoretical model (TTM) provides useful constructs that address family caregivers' readiness to change their self-help and help-seeking behaviors. This paper reviews relevant literature regarding Learned Resourcefulness, Resourcefulness, and the TTM. The proposed conceptual model incorporates constructs from the TTM integrated with Learned Resourcefulness and Resourcefulness strategies to aid in the development and testing of interventions that are designed to promote the quality of life and health of older family caregivers while they are providing care to disabled older adults.

Inhibitory Effect of Apigenin on Losartan Metabolism and CYP2C9 Activity in vitro.

BACKGROUND: CYP2C9 is one of the most important phase I drug-metabolizing enzymes in liver. The objective of this work was to investigate the effects of apigenin on the metabolism of losartan and human CYP2C9 and rat CYP2C11 activity in vitro. METHODS: Different concentrations of apigenin were added to a 100 mmol/l Tris-HCl reaction mixture containing 2 pmol/ml recombinant human CYP2C9.1, 0.25 mg/ml human liver microsomes or 0.5 mg/ml rat liver microsomes to determine the half maximal inhibition or a half-maximal inhibitory concentration (IC50) on the metabolism of losartan. In addition, diclofenac used as CYP2C9 substrate was performed to determine the effects of apigenin on CYP2C9. RESULTS: The results showed that apigenin has the inhibitory effect on the metabolism of losartan in vitro, the IC50 was 7.61, 4.10 and 11.07 µmol/l on recombinant CYP2C9 microsomes, human liver microsomes and rat liver microsomes, respectively. Meanwhile, apigenin's mode of action on human CYP2C9 activity was competitive for the substrate diclofenac. In contrast to its potent inhibition of CYP2C9 in humans (9.51 µmol/l), apigenin had lesser effects on CYP2C11 in rat (IC50 = 15.51 µmol/l). CONCLUSION: The observations imply that apigenin has the inhibitory effect on the metabolism of losartan and CYP2C9 activity in vitro. More attention should be paid as to when losartan should be administrated combined with apigenin.

Structural characteristics of the nonallosteric human cytosolic malic enzyme.

Human cytosolic NADP(+)-dependent malic enzyme (c-NADP-ME) is neither a cooperative nor an allosteric enzyme, whereas mitochondrial NAD(P)(+)-dependent malic enzyme (m-NAD(P)-ME) is allosterically activated by fumarate. This study examines the molecular basis for the different allosteric properties and quaternary structural stability of m-NAD(P)-ME and c-NADP-ME. Multiple residues corresponding to the fumarate-binding site were mutated in human c-NADP-ME to correspond to those found in human m-NAD(P)-ME. Additionally, the crystal structure of the apo (ligand-free) human c-NADP-ME conformation was determined. Kinetic studies indicated no significant difference between the wild-type and mutant enzymes in Km,NADP, Km,malate, and kcat. A chimeric enzyme, [51-105]_c-NADP-ME, was designed to include the putative fumarate-binding site of m-NAD(P)-ME at the dimer interface of c-NADP-ME; however, this chimera remained nonallosteric. In addition to fumarate activation, the quaternary structural stability of c-NADP-ME and m-NAD(P)-ME is quite different; c-NADP-ME is a stable tetramer, whereas m-NAD(P)-ME exists in equilibrium between a dimer and a tetramer. The quaternary structures for the S57K/N59E/E73K/S102D and S57K/N59E/E73K/S102D/H74K/D78P/D80E/D87G mutants of c-NADP-ME are tetrameric, whereas the K57S/E59N/K73E/D102S m-NAD(P)-ME quadruple mutant is primarily monomeric with some dimer formation. These results strongly suggest that the structural features near the fumarate-binding site and the dimer interface are highly related to the quaternary structural stability of c-NADP-ME and m-NAD(P)-ME. In this study, we attempt to delineate the structural features governing the fumarate-induced allosteric activation of malic enzyme.

Effect of CYP2C9 genetic polymorphism on the metabolism of flurbiprofen in vitro.

CYP2C9 is an important member of the cytochrome P450 enzyme superfamily, and 57 cytochrome P450 2C9 alleles have been previously reported. To examine the enzymatic activity of the CYP2C9 alleles, kinetic parameters for 4'-hydroxyflurbiprofen were determined using recombinant human P450s CYP2C9 microsomes from insect cells Sf21 carrying wild-type CYP2C9*1 and other variants. The results showed that the enzyme activity of most of the variants decreased comparing with the wild type as the previous studies reported, while the enzyme activity of some of them increased, which were not in accordance with the previous researches. Of the 36 tested CYP2C9 allelic isoforms, two variants (CYP2C9*53 and CYP2C9*56) showed a higher intrinsic clearance value than the wild-type protein, especially for CYP2C9*56, exhibited much higher intrinsic clearance (197.3%) relative to wild-type CYP2C9*1, while the remaining 33 CYP2C9 allelic isoforms exhibited significantly decreased clearance values (from 0.6 to 83.8%) compared to CYP2C9*1. This study provided the most comprehensive data on the enzymatic activities of all reported CYP2C9 variants in the Chinese population with regard to the commonly used non-steroidal anti-inflammatory drug, flurbiprofen (FP). The results indicated that most of the tested rare alleles decreased the catalytic activity of CYP2C9 variants toward FP hydroxylation in vitro. This is the first report of all these rare alleles for FP metabolism providing fundamental data for further clinical studies on CYP2C9 alleles for FP metabolism in vivo.

The role of CYP2C9 genetic polymorphisms in the oxidative metabolism of diclofenac in vitro.

CYP2C9 is one of four known members of the human cytochrome P450 CYP2C superfamily, with at least 57 CYP2C9 alleles being previously identified. Genetic polymorphisms of CYP2C9 significantly influence the efficacy and safety of some drugs, which might cause adverse effects and therapeutic failure. The purpose of the present study was to clarify the role of 36 CYP2C9 alleles, 21 novel alleles (*36-*56) found in the Chinese population, in the oxidative metabolism of diclofenac in vitro. Insect microsomes expressing the 36 human CYP2C9 alleles were incubated with 2-100 µM diclofenac for 30 min at 37 degrees C and terminated by the addition of 30 µL 0.1 M HCl. Diclofenac and 4'-hydroxyl (OH)-diclofenac, the major diclofenac metabolite, were analyzed by high-performance liquid chromatography (HPLC). Compared with wild-type CYP2C9*1, most variants showed significantly altered values in V(max), K(m) and intrinsic clearance (V(max)/K(m)). Only one variant exhibited markedly increased intrinsic clearance value, whereas 31 variants exhibited significantly decreased values. Thus, this study demonstrated that more attention should be given to subjects carrying these CYP2C9 alleles when administering diclofena.

SOURCE, a learned resourcefulness program to reduce caregiver burden and improve quality of life for older family caregivers.

BACKGROUND: Family members often undertake caregiving responsibilities over long periods of time, which could lead to caregiving burden. A theory-based and culturally sensitive learned resourcefulness program may help family caregivers mitigate stress by learning and using self-help strategies. OBJECTIVES: This study's aim is to use rigorous methods to investigate the effects of a learned resourcefulness program called SOURCE (Chen et al., Geriatric Nursing, 2021, 45, 1129) to reduce caregiver burden and improve quality of life (QOL) for family caregivers. SOURCE is an acronym for the six self-help behaviors at the core of this theory-based learned resourcefulness program, developed by the Principal Investigator (PI) in collaboration with other researchers (Chen et al., Geriatric Nursing, 2021, 45, 1129). These behaviors are: seeking problem-solving strategies, organizing daily actions, using self-regulation, reframing positive situations, changing negative self-thinking, and exploring new thinking and skills. METHODS: We used a quasi-experimental design with repeated measures for this study. The potential subjects were family caregivers whose family member was receiving home care. PI recruited 94 family caregivers (60 years old or older) who were caring for disabled and/or ill family members who also were 60 years old or older and living at home at the time of the study. The PI recruited these caregivers through the home care services department of a hospital and two community healthcare centers in Taiwan. The experimental group (n = 46) received the four-week in-person SOURCE while their family member continued to receive home care services, whereas the control group (n = 48) did not receive the SOURCE program while their family member received home care services. We collected data from the participants using the Caregiver Burden Scale, EuroQol-5 Dimension, and Rosenbaum's Self-Control Scale at baseline (T0, Week 1), after the intervention (T1, Week 5), and at follow-up (T2, Week 9). We analyzed the data using paired-sample t-tests and used the generalized estimating equation method to compare paired data between the baseline and follow-up. RESULTS: Of the 94 recruited family caregivers, 90.4% (n = 85) completed the study. We found no significant differences between the experimental and control groups in terms of demographic, caregiver burden, and QOL variables at baseline. Compared to the control group, the experimental group had significantly improved caregiver burden scores (indicating a reduction in caregiver burden) at the end of the intervention and at follow-up. The experimental group had significantly improved QOL scores at follow-up only. The experimental group also showed high levels of adherence to and satisfaction with the intervention. The paired-sample t-test results show significantly improved learned resourcefulness between T0 and T1 and between T0 and T2 (t = -5.84, p < 0.001; t = -6.77, p < 0.001) for the experimental group. CONCLUSION: The SOURCE program helped family caregivers develop and use self-help behaviors during their daily caregiving tasks. The family caregivers reported satisfaction with the program as well as reduced caregiver burden and improved QOL after the program ended. IMPLICATIONS FOR PRACTICE: The SOURCE program can be implemented to improve family caregivers' caregiver burden and QOL. Community health nurses can improve self-help abilities of family caregivers by helping them to acquire abilities and skills that allow them to effectively handle stress and reduce their caregiver burden.

The Effectiveness of On-Demand Health Education Systems in Assisting the Nursing Workload.

This article explores the "On-Demand Health Education System" in healthcare, highlighting its role in enhancing nursing efficiency and quality. Using a database, it allows nurses to provide tailored education via QR codes for patients and families. Key findings show its positive impact on education quality and efficiency, though improvements are needed in user interface and accessibility for certain groups like the elderly. Future enhancements should focus on user experience and expanding accessibility, acknowledging the potential of such systems in medical education with technological advancement.

Implementation of an Automated Dispensing Cabinet System and Its Impact on Drug Administration: Longitudinal Study.

BACKGROUND: A technology that has been widely implemented in hospitals in the United States is the automated dispensing cabinet (ADC), which has been shown to reduce nurse drug administration errors and the time nurses spend administering drugs. OBJECTIVE: This study aimed to determine the impact of an ADC system on medication administration by nurses as well as safety before and after ADC implementation. METHODS: We conducted a 24-month-long longitudinal study at the National Taiwan University Hospital in Taipei, Taiwan. Clinical observations and questionnaires were used to evaluate the time differences in drug preparation, delivery, and returns in the inpatient ward by nurses before and after using the ADC. Drug errors recorded in the Medical Incident Events system were assessed the year before and after ADC implementation. RESULTS: The drug preparation time of the wards increased significantly (all P<.005). On average, 2 minutes of preparation time is needed for each patient. Only 1 unit showed an increase in the drug return time, but this was not significant. There were 9 (45%) adverse events during the drug administration phase, and 11 (55%) events occurred during the drug-dispensing phase. Although a decrease in the mean number of events reported was observed during the ADC implementation period, this difference was not significant. As for the questionnaire that were administered to the nurses, the overall mean score was 3.90; the highest score was for the item "I now spend less time waiting for medications that come from the pharmacy than before the ADC was implemented" (score=4.24). The item with the lowest score was "I have to wait in line to get my patient medications" (score=3.32). CONCLUSIONS: The nurses were generally satisfied with ADC use over the 9 months following complete implementation and integration of the system. It was acknowledged that the ADC offers benefits in terms of pharmaceutical stock management; however, this comes at the cost of increased nursing time. In general, the nurses remained supportive of the benefits for their patients, despite consequences to their workflows. Their acceptance of the ADC system in this study demonstrates this.

Develop a Mobile Nursing App to Improve Nursing Workflow and Effectiveness Assessment.

We develop a mobile care application that includes tools such as voice input, image upload, and image recognition. This procedure will be used in clinical care. The study is expected to undergo actual use testing in the ward and a questionnaire survey three months after use. During use, the mobile phone connection data will continuously monitor to analyze the number and time of connection records.

Elastic Band Exercises Improved Activities of Daily Living and Functional Fitness of Wheelchair-bound Older Adults with Cognitive Impairment: A Cluster Randomized Controlled Trial.

OBJECTIVE: The purpose of this study was to test the effects of a 6-month Wheelchair-bound Senior Elastic Band (WSEB) exercise program on the activities of daily living (ADL) and functional fitness of wheelchair-bound older adults with cognitive impairment. DESIGN: Cluster randomized controlled trial was used. A convenience sample of 138 wheelchair-bound older adults with cognitive impairment were recruited from 8 nursing homes in southern Taiwan and were randomly assigned based on the nursing homes they lived to the experimental (4 nursing homes; n = 73) or the control group (4 nursing homes; n = 65). The experimental group performed WSEB exercises 3 times per week and 40 minutes per session for 6 months. The ADL and functional fitness (cardiopulmonary function, body flexibility, range of joint motion, and muscle strength and endurance) were examined at baseline, 3 months, and the end of 6-month study. RESULTS: The ADL and functional fitness indicators of participants in the experimental group showed significant improvements compared to the control group (all P < 0.05). CONCLUSIONS: The WSEB exercises have positive benefits for the ADL and functional fitness of wheelchair-bound older adults with cognitive impairment. It is suggested that WSEB exercises be included as a routine activity in nursing homes. TO CLAIM CME CREDITS: Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCMECME OBJECTIVES:: Upon completion of this article the reader should be able to: (1) Understand the risk factors for functional decline in older adults with dementia; (2) Articulate the benefits of structured activities and exercises in the older adult with dementia; and (3) Incorporate elastic band exercises into the treatment plan of wheelchair bound older adults with dementia. LEVEL: AdvancedACCREDITATION:: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The Association of Academic Physiatrists designates this activity for a maximum of 1.5 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Caregiver burden, health status, and learned resourcefulness of older caregivers.

As caregivers undertake caregiving responsibilities over a long period of time, the burdens placed on them could lead to undue stress and affect their health. This correlation study examined the current situations and relationships among caregiver burden, health status, and learned resourcefulness (LR) of older caregivers who care for disabled older adults, and predicted the important factors that affect their caregiver burden. In all, 108 older caregivers were recruited from home care services of two hospitals. Structured questionnaire interviews were applied to collect data: the Caregiver Burden Scale, the SF-36 Health Survey (SF-36), and the Rosenbaum's Self-Control Schedule. Results indicated that the caregiver burden was negatively correlated with physical health, mental health, and LR. Physical and mental health were positively correlated with LR. The predictors of caregiver burden included LR, health status, economic status, and activities of daily living, which accounted for 58.60% of the total caregiver burden variance.

The development of bioactive peptides from dietary proteins as a dipeptidyl peptidase IV inhibitor for the management of type 2 diabetes.

One of the new approaches to the management of type 2 diabetes mellitus (T2DM) consists of orally administered dipeptidyl peptidase-IV (DPP-IV) inhibitors. These synthetic drug inhibitors are reported to have some side effects and that subsequently limits their applications. There is a growing interest to develop natural DPP-IV inhibitors that will be potent without undesirable side effects. Many in vitro and some in vivo studies have highlighted the potential of food-derived peptides functioning as effective DPPIV inhibitors. Bioactive peptides within original food-derived proteins are inactive but can be activated by being released during food processing (by enzymatic hydrolysis or fermentation) or during gastrointestinal digestion. Hence, the utilization of computer-aided techniques as screening tools may be helpful in predicting the potential of food proteins as precursors of DPP-IV inhibitory peptides. This paper reviews the current literature on DPP-IV inhibitory peptides, focusing on their in vitro activity and in vivo antidiabetic effects. In addition, the feasibility of various in silico approaches is also summarized in this review.

Kinetic origin of grain boundary migration, grain coalescence, and defect reduction in the crystallization of quenched two-dimensional Yukawa liquids.

The kinetic origin of grain boundary migration, grain coalescence, and defect reduction in the crystallization of quenched two-dimensional Yukawa liquids are numerically investigated. It is found that, in grain coalescence, stick-slip cracking the region in front of the grain boundary into smaller subgrains corotating with small angle, followed by healing, is the key for aligning lattice misorientation and inducing grain boundary stick-slip advance. Cracking is initiated from the weakly interlocked dislocation along its Burgers vector, which in turn causes dislocation motion along the crack. The cascaded scattering and recombination of two dislocations with 60^{∘} and 120^{∘} Burgers vector angle difference into two and one dislocations are the major processes for dislocation motion and reduction, respectively, in grain boundary migration. A rough grain boundary with large curvature easily supports the above process and induces high grain boundary mobility. Along a straight smooth grain boundary, the parallel Burgers vectors of the string of dislocations hinder defect reduction and induce coalescence stagnation.

Matrine attenuates allergic airway inflammation and eosinophil infiltration by suppressing eotaxin and Th2 cytokine production in asthmatic mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Matrine has been isolated from Sophora flavescens, and found to show anti-inflammatory effects in macrophages and anti-cachectic effects in hepatomas. The present study investigated whether matrine suppressed eosinophil infiltration and airway hyperresponsiveness (AHR) in mice, and decreased the inflammatory response of tracheal epithelial cells. MATERIALS AND METHODS: BALB/c mice were sensitized and challenged with ovalbumin to induce allergic asthma in mice. These asthmatic mice were given various doses of matrine by intraperitoneal injection. Additionally, activated human tracheal epithelial cells (BEAS-2B cells) were treated with matrine, and evaluated for levels of proinflammatory cytokines and chemokines. RESULTS: We found that matrine significantly decreased AHR, and suppressed goblet cell hyperplasia, eosinophil infiltration, and inflammatory response in the lung tissue of asthmatic mice. Matrine also reduced the levels of Th2 cytokines and chemokines in bronchoalveolar lavage fluid, and suppressed OVA-IgE production in serum. Furthermore, matrine treatment of activated BEAS-2B cells decreased production of proinflammatory cytokines and eotaxins, as well as suppressed ICAM-1 expression and thus adhesion of eosinophils to inflammatory BEAS-2B cells in vitro. CONCLUSIONS: Our findings suggest that matrine can improve allergic asthma in mice, and therefore has potential therapeutic potential in humans.

Oral lovastatin attenuates airway inflammation and mucus secretion in ovalbumin-induced murine model of asthma.

PURPOSE: Lovastatin is an effective inhibitor of cholesterol synthesis. A previous study demonstrated that lovastatin can also suppress airway hyperresponsiveness (AHR) in murine model of asthma. We aimed to investigate the effect of lovastatin on mucus secretion and inflammation-associated gene expression in the lungs of murine model of asthma. METHODS: Female BALB/c mice were sensitized and challenged with ovalbumin (OVA) by intraperitoneal injection, and orally administered lovastatin from days 14 to 27 post-injection. Gene expression in lung tissues was analyzed using real-time polymerase chain reaction. AHR and goblet cell hyperplasia were also examined. BEAS-2B human bronchial epithelial cells were used to evaluate the effect of lovastatin on the expression of cell adhesion molecules, chemokines, and proinflammatory cytokines in vitro. RESULTS: We showed that lovastatin inhibits the expression of Th2-associated genes, including eotaxins and adhesion molecules, in the lungs of murine model of asthma. Mucin 5AC expression, eosinophil infiltration and goblet cell hyperplasia were significantly decreased in the lung tissue of murine model of asthma treated with lovastatin. Furthermore, lovastatin inhibited AHR and expression of Th2-associated cytokines in bronchoalveolar lavage fluid. However, a high dose (40 mg/kg) of lovastatin was required to decrease specific IgE to OVA levels in serum, and suppress the expression of Th2-associated cytokines in splenocytes. Activated BEAS-2B cells treated with lovastatin exhibited reduced IL-6, eotaxins (CCL11 and CCL24), and intercellular adhesion molecule-1 protein expression. Consistent with this, lovastatin also suppressed the ability of HL-60 cells to adhere to inflammatory BEAS-2B cells. CONCLUSIONS: These data suggest that lovastatin suppresses mucus secretion and airway inflammation by inhibiting the production of eotaxins and Th2 cytokines in murine model of asthma.

The effect of apigenin on pharmacokinetics of imatinib and its metabolite N-desmethyl imatinib in rats.

The purpose of this study was to determine the effect of apigenin on the pharmacokinetics of imatinib and N-desmethyl imatinib in rats. Healthy male SD rats were randomly divided into four groups: A group (the control group), B group (the long-term administration of 165 mg/kg apigenin for 15 days), C group (a single dose of 165 mg/kg apigenin), and D group (a single dose of 252 mg/kg apigenin). The serum concentrations of imatinib and N-desmethyl imatinib were measured by HPLC, and pharmacokinetic parameters were calculated using DAS 3.0 software. The parameters of AUC(0-t), AUC(0-∞), Tmax, V(z)/F, and CL(z)/F for imatinib in group B were different from those in group A (P < 0.05). Besides, MRT(0-t) and MRT(0-∞) in groups C and D differed distinctly from those in group A as well. The parameters of AUC(0-t) and Cmax for N-desmethyl imatinib in group C were significantly lower than those in group A (P < 0.05); however, compared with groups B and D, the magnitude of effect was modest. Those results indicated that apigenin in the short-term study inhibited the metabolism of imatinib and its metabolite N-desmethyl imatinib, while in the long-term study the metabolism could be accelerated.

Determinants of nucleotide-binding selectivity of malic enzyme.

Malic enzymes have high cofactor selectivity. An isoform-specific distribution of residues 314, 346, 347 and 362 implies that they may play key roles in determining the cofactor specificity. Currently, Glu314, Ser346, Lys347 and Lys362 in human c-NADP-ME were changed to the corresponding residues of human m-NAD(P)-ME (Glu, Lys, Tyr and Gln, respectively) or Ascaris suum m-NAD-ME (Ala, Ile, Asp and His, respectively). Kinetic data demonstrated that the S346K/K347Y/K362Q c-NADP-ME was transformed into a debilitated NAD⁺-utilizing enzyme, as shown by a severe decrease in catalytic efficiency using NADP⁺ as the cofactor without a significant increase in catalysis using NAD⁺ as the cofactor. However, the S346K/K347Y/K362H enzyme displayed an enhanced value for k(cat,NAD), suggesting that His at residue 362 may be more beneficial than Gln for NAD⁺ binding. Furthermore, the S346I/K347D/K362H mutant had a very large K(m,NADP) value compared to other mutants, suggesting that this mutant exclusively utilizes NAD⁺ as its cofactor. Since the S346K/K347Y/K362Q, S346K/K347Y/K362H and S346I/K347D/K362H c-NADP-ME mutants did not show significant reductions in their K(m,NAD) values, the E314A mutation was then introduced into these triple mutants. Comparison of the kinetic parameters of each triple-quadruple mutant pair (for example, S346K/K347Y/K362Q versus E314A/S346K/K347Y/K362Q) revealed that all of the K(m) values for NAD⁺ and NADP(+) of the quadruple mutants were significantly decreased, while either k(cat,NAD) or k(cat,NADP) was substantially increased. By adding the E314A mutation to these triple mutant enzymes, the E314A/S346K/K347Y/K362Q, E314A/S346K/K347Y/K362H and E314A/S346I/K347D/K362H c-NADP-ME variants are no longer debilitated but become mainly NAD⁺-utilizing enzymes by a considerable increase in catalysis using NAD⁺ as the cofactor. These results suggest that abolishing the repulsive effect of Glu314 in these quadruple mutants increases the binding affinity of NAD⁺. Here, we demonstrate that a series of E314A-containing c-NADP-ME quadruple mutants have been changed to NAD⁺-utilizing enzymes by abrogating NADP⁺ binding and increasing NAD⁺ binding.