Oligomeric proanthocyanidins ameliorates osteoclastogenesis through reducing OPG/RANKL ratio in chicken's embryos.

Skeletal disorders can seriously threaten the health and the performance of poultry, such as tibial dyschondroplasia (TD) and osteoporosis (OP). Oligomeric proanthocyanidins (OPC) are naturally occurring polyphenolic flavonoid compounds that can be used as potential substances to improve the bone health and the growth performance of poultry. Eighty 7-day-old green-eggshell yellow feather layer chickens were randomly divided into 4 groups: basal diet and basal diet supplementation with 25, 50, and 100 mg/kg OPC. The results have indicated that the growth performance and bone parameters of chickens were significantly improved supplementation with OPC in vivo, including the bone volume (BV), the bone mineral density (BMD) and the activities of antioxidative enzymes, but ratio of osteoprotegerin (OPG)/receptor activator of NF-κB (RANK) ligand (RANKL) was decreased. Furthermore, primary bone marrow mesenchymal stem cells (BMSCs) and bone marrow monocytes/macrophages (BMMs) were successfully isolated from femur and tibia of chickens, and co-cultured to differentiate into osteoclasts in vitro. The osteogenic differentiation derived from BMSCs was promoted treatment with high concentrations of OPC (10, 20, and 40 µmol/L) groups in vitro, but emerging the inhibition of osteoclastogenesis by increasing the ratio of OPG/RANKL. In contrary, the osteogenic differentiation was also promoted treatment with low concentrations of OPC (2.5, 5, and 10 µmol/L) groups, but osteoclastogenesis was enhanced by decreasing the ratio of OPG/RANKL in vitro. In addition, OPG inhibits the differentiation and activity of osteoclasts by increasing the autophagy in vitro. Dietary supplementation of OPC can improve the growth performance of bone and alter the balance of osteoblasts and osteoclasts, thereby improving the bone health of chickens.

A phase IV study to evaluate the safety of fruquintinib in Chinese patients in real-world clinical practice.

INTRODUCTION: Fruquintinib is approved in China for patients with metastatic colorectal cancer (CRC) who progressed after 2 lines of chemotherapy. This postmarketing study was conducted to evaluate the safety of fruquintinib in the Chinese population, including previously treated patients with advanced CRC and other solid tumors. METHODS: Patients in the first cycle of fruquintinib or expected to start fruquintinib within a week were enrolled. Fruquintinib was administrated according to the label or per physicians' discretion. Patient characteristics and safety information were collected at baseline, 1 month, and 6 months after consent (or 30 days after the last dose). RESULTS: Overall, 3005 patients enrolled between April 24, 2019 and September 27, 2022. All enrolled patients received at least one dose of fruquintinib. Most patients had metastases at baseline. The median age was 60 years. More than half (64.0%) of the patients started fruquintinib at 5 mg, and the median treatment exposure was 2.7 months. Nearly one-third (32.5%) of patients with CRC received fruquintinib with concomitant antineoplastic agents. Treatment-emergent adverse events (TEAEs) leading to dose modification were reported in 626 (20.8%) patients, and 469 (15.6%) patients experienced TEAEs leading to treatment discontinuation. The most common grade ≥ 3 TEAEs were hypertension (6.6%), palmar-plantar erythrodysesthesia syndrome (2.2%), and platelet count decreased (1.0%). Combination therapy did not lead to excessive toxicities. CONCLUSIONS: The safety profile of fruquintinib in the real world was generally consistent with that in clinical studies, and the incidence of TEAEs was numerically lower than known VEGF/VEGFR inhibitor-related AEs. Fruquintinib exhibited manageable safety and tolerability in Chinese patients in the real-world setting.

Polystyrene exacerbates cadmium-induced mitochondrial damage to lung by blocking autophagy in mice.

Cadmium (Cd) is an environmental heavy metal, and its accumulation is harmful to animal and human health. The cytotoxicity of Cd includes oxidative stress, apoptosis, and mitochondrial histopathological changes. Furthermore, polystyrene (PS) is a kind of microplastic piece derived from biotic and abiotic weathering courses, and has toxicity in various aspects. However, the potential mechanism of action of Cd co-treated with PS is still poorly unclear. The objective of this study was to investigate the effects of PS on Cd-induced histopathological injury of mitochondria in the lung of mice. In this study, the results have showed that Cd could induce the activity of oxidative enzymes of the lung cells in mice, increasing the content of partial microelement and the phosphorylation of inflammatory factor NF-κB p65. Cd further destroys the integrity of mitochondria by increasing the expression of apoptotic protein and blocking the autophagy. In addition, PS solely group aggravated the lung damage in mice, especially mitochondrial toxicity, and played a synergistic effect with Cd in lung injury. However, how PS can augment mitochondrial damage and synergism with Cd in lung of mice requiring further exploration. Therefore, PS was able to exacerbate Cd-induced mitochondrial damage to the lung in mice by blocking autophagy, and was associated with the apoptosis.

A Review of Signaling Transduction Mechanisms in Osteoclastogenesis Regulation by Autophagy, Inflammation, and Immunity.

Osteoclastogenesis is an ongoing rigorous course that includes osteoclast precursors fusion and bone resorption executed by degradative enzymes. Osteoclastogenesis is controlled by endogenous signaling and/or regulators or affected by exogenous conditions and can also be controlled both internally and externally. More evidence indicates that autophagy, inflammation, and immunity are closely related to osteoclastogenesis and involve multiple intracellular organelles (e.g., lysosomes and autophagosomes) and certain inflammatory or immunological factors. Based on the literature on osteoclastogenesis induced by different regulatory aspects, emerging basic cross-studies have reported the emerging disquisitive orientation for osteoclast differentiation and function. In this review, we summarize the partial potential therapeutic targets for osteoclast differentiation and function, including the signaling pathways and various cellular processes.

Puerarin alleviates cadmium-induced oxidative damage to bone by reducing autophagy in rats.

Autophagy is a regulatory mechanism involved in cadmium (Cd)-induced bone toxicity and is suppressed by various stimuli, including oxidative stress. Puerarin is an isoflavonoid compound isolated from Pueraria, a plant used in traditional Chinese medicine. The underlying mechanisms of action of puerarin remain unclear. The objective of this study was to explore the mitigating effects of puerarin on cadmium-induced oxidative damage in the bones of rats. Cadmium exposure increased oxidative damage in rat bones; this was markedly decreased by puerarin treatment, as demonstrated by changes in the activity of antioxidative enzymes. Cadmium-induced blockage of the expression of key bone regulatory proteins, autophagy-related markers, and signaling molecules was also alleviated by puerarin treatment. Additionally, cadmium reduced expression of the autophagic protein Rab7 and of late endosomal/lysosomal adaptor and MAPK and mTOR activator 1 (LAMTOR1); the decrease in these proteins was not restored by puerarin treatment. We speculate that puerarin relieves the inhibition of fusion of autophagosomes with lysosomes that is induced by cadmium; however, this specific effect of puerarin and downstream effects on bone regulatory mechanisms require further investigation. In conclusion, puerarin alleviates cadmium-induced oxidative damage in the bones of rats by attenuating autophagy, which is likely associated with the antioxidant activity of puerarin.

Gemcitabine Plus Cisplatin Versus Fluorouracil Plus Cisplatin as First-Line Therapy for Recurrent or Metastatic Nasopharyngeal Carcinoma: Final Overall Survival Analysis of GEM20110714 Phase III Study.

PURPOSE: GEM20110714 (ClinicalTrials.gov identifier: NCT01528618), the first randomized, phase III study of systemic chemotherapy in recurrent or metastatic nasopharyngeal carcinoma (NPC), reported significant progression-free survival improvement with gemcitabine plus cisplatin (GP) versus fluorouracil plus cisplatin (FP; hazard ratio, 0.55; 95% CI, 0.44 to 0.68; P < .001). Data from the final analysis of overall survival (OS) are presented here. METHODS: From February 2012 to October 2015, 362 patients were randomly assigned to receive either GP (gemcitabine 1 g/m2 once daily on days 1 and 8 and cisplatin 80 mg/m2 once daily on day 1; n = 181) or FP (fluorouracil 4 g/m2 in continuous intravenous infusion over 96 hours and cisplatin 80 mg/m2 once daily on day 1; n = 181) once every 21 days. The primary end point was progression-free survival, which has been previously reported; OS was a secondary end point. RESULTS: After a median follow-up time of 69.5 months with GP and 69.7 months with FP, 148 (81.8%) and 166 (91.7%) deaths occurred in the GP and FP arms, respectively. The estimated hazard ratio for OS was 0.72 (95% CI, 0.58 to 0.90; two-sided P = .004). The median OS was 22.1 months (95% CI, 19.2 to 25.0 months) with GP versus 18.6 months (95% CI, 15.4 to 21.7 months) with FP. The OS probabilities at 1, 3, and 5 years were 79.9% versus 71.8%, 31.0% versus 20.4%, and 19.2% versus 7.8%, respectively. Poststudy therapy was administered in 51.9% and 55.2% of patients in the GP and FP arms, respectively. CONCLUSION: Among patients with previously untreated advanced nasopharyngeal carcinoma, those who receive GP have longer OS than those receive FP. Gemcitabine plus cisplatin should be considered a preferred front-line option for these patients.

Red Blood Cell Distribution Width as a Predictive Marker for Coronary Artery Lesions in Patients with Kawasaki Disease.

This study aimed to investigate the association between red blood cell distribution width (RDW) and the risk of coronary artery lesions (CALs) in patients with Kawasaki disease (KD). A total of 1355 patients who met the diagnostic criteria for KD were reviewed between January 2018 and December 2019, including 636 patients with CALs and 719 patients without CALs. Blood samples for RDW were obtained at admission (before intravenous immunoglobulin treatment). A logistic regression analysis was performed, and a receiver operating characteristic curve was constructed to determine the prognostic value of RDW standard deviation (RDW-SD) and RDW coefficient of variation (RDW-CV). The study was registered at www.chictr.org.cn , No.: ChiCTR 2000040980. The results showed that RDW-SD increased in patients with complete KD and CALs compared with patients with complete KD without CALs (39 fL vs. 38 fL, respectively; p = 0.000). RDW-CV in patients with complete KD and CALs was significantly higher compared with patients with completed KD without CALs (p = 0.000). Further multivariate logistic regression analysis revealed that RDW-SD was an independent marker of CALs in patients with complete KD (p = 0.001), but no association was found between RDW-CV and CALs. The area under the curve of RDW-SD for predicting CALs in patients with complete KD was 0.606 (95% confidence interval 0.572-0.640; p = 0.000) with a sensitivity and specificity of 61% and 55%, respectively, when the optimal cut-off value of RDW-SD was 38.5 fL. RDW-CV increased in patients with incomplete KD and CALs compared with patients without CALs (13.55% vs 13.3%, respectively; p = 0.004), and multivariate logistic regression analysis revealed that RDW-CV was an independent marker of CALs in patients with incomplete KD (p = 0.021). The area under the curve of RDW-CV for predicting CALs in patients with incomplete KD was 0.597 (95% confidence interval 0.532-0.661; p = 0.004) with a sensitivity and specificity of 40% and 77%, respectively, when the optimal cut-off value of RDW-SD was 13.85%. Conclusion: RDW can be used as an independent predictive marker of CALs in patients with KD, but the type of KD should be considered. RDW-SD was an independent marker of CALs in patients with complete KD, while RDW-CV was a predictor of incomplete KD.

Acute recurrent rhabdomyolysis in a Chinese boy associated with a novel compound heterozygous LPIN1 variant: a case report.

BACKGROUND: LPIN1-related acute recurrent rhabdomyolysis (RM), first reported in 2008, is an autosomal recessive inherited metabolic disease. In recent years, LPIN1 gene variants have been identified as one of the main causes of severe RM in children in Western countries. The disease is extremely rare in China, and we report a case of acute recurrent RM caused by a novel compound heterozygous LPIN1 variant. CASE PRESENTATION: A 15-year-old Chinese boy presented with myalgia after strenuous exercise, accompanied by transient increases in serum creatine kinase and myoglobin and persistent hyperuricaemia and hyperbilirubinaemia. Genetic analysis using high-throughput genomic sequencing and Sanger sequencing revealed that there was a compound heterozygous variant in the LPIN1 gene of the proband: the paternal c.2047A > G(p.I683V) was an unreported missense variant, and the maternal c.2107_2108 insAGG(p.Q703delin sQE) was an unreported in-frame variant. CONCLUSIONS: In children with RM, LPIN1 variants should always be considered in the differential diagnosis. The clinical features of our case are atypical, which highlights the importance of an accurate diagnosis by genetic testing. If detected early, the condition may be controlled, and the prognosis may be improved.

Septin 9 Methylation in Nasopharyngeal Swabs: A Potential Minimally Invasive Biomarker for the Early Detection of Nasopharyngeal Carcinoma.

Nasopharyngeal carcinoma (NPC) is highly prevalent in Southeast Asia, and an unfavorable outcome is usually attributed to advanced stage NPC. Current methods for the early diagnosis of NPC have limitations in clinical practice. The aim of this study was to investigate the diagnostic ability of Septin 9 methylation for NPC. A quantitative methylation-sensitive PCR (qMS-PCR) assay was developed to measure the methylation status and levels of Septin 9 in nasopharyngeal tissues and paired swabs from patients with NPC, chronic nasopharyngitis, and healthy donors. Methylated Septin 9 was detected in 92% (23/25) of NPC tissues and 25% (4/16) of nasopharyngitis controls (p < 0.05). High-frequency hypermethylation with decreased mRNA expression of Septin 9 in NPC was also identified. Further, Septin 9 methylation was identified in 90.5% (19/21) of NPC biopsies and 71.4% (15/21) of paired swabs, indicating a good concordance between the two sample types. In addition, methylated Septin 9 was found in 16 (72.7%) nasal swabs from 22 NPC patients, 2 of 19 (10.5%) nasopharyngitis, but not in any of the healthy controls (p < 0.01). The methylation score in nasal swabs of the NPC group was also significantly higher than that of non-NPC controls (p < 0.001). Moreover, receiver operating characteristic (ROC) curve analysis showed an area under the curve (AUC) of 0.882 of Septin 9 methylation tests to discriminate NPC from non-NPC subjects. Our study demonstrated that frequent methylation of Septin 9 was present in NPC. Its detection in nasopharyngeal swabs may provide a minimally invasive and informative method for identifying early NPC cases.

Gemcitabine plus cisplatin versus fluorouracil plus cisplatin in recurrent or metastatic nasopharyngeal carcinoma: a multicentre, randomised, open-label, phase 3 trial.

BACKGROUND: Outcomes are poor for patients with recurrent or metastatic nasopharyngeal carcinoma and no well established first-line chemotherapy is available for the disease. We compared the efficacy and safety of gemcitabine plus cisplatin versus fluorouracil plus cisplatin in patients with recurrent or metastatic nasopharyngeal carcinoma. METHODS: In this multicentre, randomised, open-label, phase 3 trial, patients with recurrent or metastatic nasopharyngeal carcinoma were recruited from 22 hospitals in China. Key inclusion criteria were Eastern Cooperative Oncology Group performance status of 0 or 1, adequate organ function, and measurable lesions according to Response Evaluation Criteria in Solid Tumors version 1.1. Patients were randomly assigned in a 1:1 ratio to receive either gemcitabine (1 g/m2 intravenously on days 1 and 8) and cisplatin (80 mg/m2 intravenously on day 1), or fluorouracil (4 g/m2 in continuous intravenous infusion over 96 h) and cisplatin (80 mg/m2 on day 1 given intravenously) once every 3 weeks for a maximum of six cycles. The randomisation was done centrally via an interactive phone response system using block randomisation with a size of six. The primary endpoint was progression-free survival assessed by the independent image committee in the intention-to-treat population. Safety analyses were done in patients who received at least one cycle of study drug. This study is ongoing and is registered with ClinicalTrials.gov, number NCT01528618. FINDINGS: Between Feb 20, 2012, and Oct 30, 2015, 362 patients were randomly assigned to a group (181 to the gemcitabine [plus cisplatin] group and 181 to the fluorouracil [plus cisplatin] group). Median follow-up time for progression-free survival was 19·4 months (IQR 12·1-35·6). The median progression-free survival was 7·0 months (4·4-10·9) in the gemcitabine group and 5·6 months (3·0-7·0) in the fluorouracil group (hazard ratio [HR] 0·55 [95% CI 0·44-0·68]; p<0·0001). A total of 180 patients in the gemcitabine group and 173 patients in the fluorouracil group were included in the safety analysis. Significantly different treatment-related grade 3 or 4 adverse events between the gemcitabine and fluorouracil groups were leucopenia (52 [29%] vs 15 [9%]; <0·0001), neutropenia (41 [23%] vs 23 [13%]; p=0·0251), thrombocytopenia (24 [13%] vs three [2%]; p=0·0007), and mucosal inflammation (0 vs 25 [14%]; <0·0001). Serious treatment-related adverse events occurred in seven (4%) patients in the gemcitabine group and ten (6%) in the fluorouracil group. Six (3%) patients in the gemcitabine group and 14 (8%) patients in the fluorouracil group discontinued treatment because of drug-related adverse events. No treatment-related deaths occurred in either group. INTERPRETATION: Gemcitabine plus cisplatin prolongs progression-free survival in patients with recurrent or metastatic nasopharyngeal carcinoma. The results establish gemcitabine plus cisplatin as the standard first-line treatment option for this population. FUNDING: Sun Yat-Sen University Clinical Research 5010 Programme, Chinese National Natural Science Foundation project (grant numbers 81372502 and 81201917), the National High Technology Research and Development Program of China (863 program numbers 2012AA02A501 and 2012AA02A502), and the Natural Science Foundation of Guangdong (grant number S2013010016564).

Ultrasound triggered image-guided drug delivery to inhibit vascular reconstruction via paclitaxel-loaded microbubbles.

Paclitaxel (PTX) has been recognized as a promising drug for intervention of vascular reconstructions. However, it is still difficult to achieve local drug delivery in a spatio-temporally controllable manner under real-time image guidance. Here, we introduce an ultrasound (US) triggered image-guided drug delivery approach to inhibit vascular reconstruction via paclitaxel (PTX)-loaded microbubbles (PLM) in a rabbit iliac balloon injury model. PLM was prepared through encapsulating PTX in the shell of lipid microbubbles via film hydration and mechanical vibration technique. Our results showed PLM could effectively deliver PTX when exposed to US irradiation and result in significantly lower viability of vascular smooth muscle cells. Ultrasonographic examinations revealed the US signals from PLM in the iliac artery were greatly increased after intravenous administration of PLM, making it possible to identify the restenosis regions of iliac artery. The in vivo anti-restenosis experiments with PLM and US greatly inhibited neointimal hyperplasia at the injured site, showing an increased lumen area and reduced the ratio of intima area and the media area (I/M ratio). No obvious functional damages to liver and kidney were observed for those animals. Our study provided a promising approach to realize US triggered image-guided PTX delivery for therapeutic applications against iliac restenosis.

Giant liposarcoma of the esophagus: A case report.

Liposarcomas rarely develop in the aerodigestive tract. Here, we present a primary esophageal liposarcoma that was discovered between the T3 and T7 levels of the esophagus during right pleural exploration of a 51-year-old male patient. The patient had presented with non-specific symptoms, including progressive dysphagia over the previous 6 mo, without complaints of chest or epigastric pain, regurgitation, or weight loss. A radical three-hole esophagectomy was performed. The tumor was extremely large (14 cm × 7.0 cm × 6.5 cm), but completely encapsulated. Upon histological examination, the tumor was diagnosed as a giant, well-differentiated esophageal liposarcoma with a dedifferentiated component. Non-specific radiological and endoscopic results during the clinical work-up delayed diagnosis until post-operative histology was performed. In this report, the clinical, radiological and endoscopic diagnostic challenges specific to the case are discussed, as well as the surgical and pathological findings.

Giant clear cell hidradenoma of the knee.

Hidradenomas, also referred to as nodular hidradenomas or clear cell hidradenomas (CCH), are benign cutaneous eccrine tumors usually 2-3 cm in dimension. Hidradenomas are relatively common; however, giant forms are rare. We report a case of an 8.0 x 6.0 x 3.0 cm clear cell hidradenoma of the left knee in a 43-year-old man. The tumor was mobile, located above the patellar tendon and was without bony involvement on imaging studies. Grossly, the resected tumor was unencapsulated and tan, with a solid and cystic cut surface showing papillary excrescences on the cyst wall. Microscopically, the tumor cells showed an infiltrative growth pattern at the periphery, however, the tumor cytology was bland and no necrosis or mitoses were identified. The overlying dermis contained hemosiderin pigment deposition and infiltration with eosinophils. Immunohistochemically, tumor cells were positive for cytokeratin, CAM5.2, p53, carcino-embryonic antigen (CEA) and epithelial membrane antigen (EMA), and negative for CD10 and Ki-67. The cytological features of hidradenomas can present diagnostic challenges, as other 'clear cell' tumors such as metastatic renal cell carcinoma should be considered. Immunohistochemical studies and differential diagnoses are discussed.

Nuclear respiratory factor 1 controls myocyte enhancer factor 2A transcription to provide a mechanism for coordinate expression of respiratory chain subunits.

Nuclear respiratory factors NRF1 and NRF2 regulate the expression of nuclear genes encoding heme biosynthetic enzymes, proteins required for mitochondrial genome transcription and protein import, and numerous respiratory chain subunits. NRFs thereby coordinate the expression of nuclear and mitochondrial genes relevant to mitochondrial biogenesis and respiration. Only two of the nuclear-encoded respiratory chain subunits have evolutionarily conserved tissue-specific forms: the cytochrome c oxidase (COX) subunits VIa and VIIa heart/muscle (H) and ubiquitous (L) isoforms. We used genome comparisons to conclude that the promoter regions of COX6A(H) and COX7A(H) lack NRF sites but have conserved myocyte enhancer factor 2 (MEF2) elements. We show that MEF2A mRNA is induced with forced expression of NRF1 and that the MEF2A 5'-regulatory region contains an evolutionarily conserved canonical element that binds endogenous NRF1 in chromatin immunoprecipitation (ChIP) assays. NRF1 regulates MEF2A promoter-reporters according to overexpression, RNA interference underexpression, and promoter element mutation studies. As there are four mammalian MEF2 isotypes, we used an isoform-specific antibody in ChIP to confirm MEF2A binding to the COX6A(H) promoter. These findings support a role for MEF2A as an intermediary in coordinating respiratory chain subunit expression in heart and muscle through a NRF1 --> MEF2A --> COX(H) transcriptional cascade. MEF2A also bound the MEF2A and PPARGC1A promoters in ChIP, placing it within a feedback loop with PGC1alpha in controlling NRF1 activity. Interruption of this cascade and loop may account for striated muscle mitochondrial defects in mef2a null mice. Our findings also account for the previously described indirect regulation by NRF1 of other MEF2 targets in muscle such as GLUT4.

Myocyte enhancer factor 2A is transcriptionally autoregulated.

MEF2 (myocyte enhancer factor 2) proteins are a small family of transcription factors that play pivotal roles in striated muscle differentiation, development, and metabolism, in neuron survival and synaptic formation, and in lymphocyte selection and activation. Products of the four mammalian MEF2 genes, MEF2A, MEF2B, MEF2C, and MEF2D, are expressed with overlapping but distinct temporospatial patterns. Toward analysis of MEF2A functions and the determinants of its regulated expression, we have mapped and begun studies of the transcriptional control regions of this gene. Heterogeneous 5'-untranslated regions of MEF2A mRNAs result from use of alternative promoters and splicing patterns. The two closely approximated TATA-less promoters are approximately 65 kb upstream of the exon containing the sole initiation codon. Ribonuclease protection and primer extension assays show that each promoter is active in various adult tissues. A canonical MEF2 site overlies the major promoter 1 transcription start site. This element specifically binds MEF2 factors, including endogenous nuclear MEF2A according to chromatin immunoprecipitation studies, and is critical to MEF2A transcription in myocytes. The site exerts reciprocal control of the alternative promoters, silencing promoter 1 and activating promoter 2 under some conditions. Erk5 and p38 MAPK signaling stimulate MEF2A expression by activating both promoters from the MEF2 element. MEF2A transcription is therefore subject to positive or negative regulation by its protein products, depending on signaling activities that influence MEF2 factor trans-activity. The sole MEF2 gene of the cephalochordate amphioxus has a similar regulatory region structure, suggesting that this mode of autoregulatory control is conserved among higher metazoan MEF2 genes.

[Relationship of plasma concentration of 5-fluorouracil with toxicity and response in patients with nasopharyngeal carcinoma].

BACKGROUND & OBJECTIVE: Because there are several mechanisms of activity and toxicity and inter-individual variation in pharmaco- dynamics of 5-fluorouracil (5-FU),it is difficult to predict the sensitivity and toxicity of 5-FU in an individual patient. This study was designed to assess inter-patient variation of 5-FU steady-state plasma concentration and the relationship of plasma concentration of 5-FU with toxic side effects and therapeutic response. METHODS: Twenty patients with nasopharyngeal carcinoma were treated with 5-FU combined with cisplatin(DDP). Blood samples were collected after 24 hours of infusion of 5-FU. Plasma concentrations of 5-FU were measured using high performance liquid chromatography(HPLC) with column temperature at 25 Celsius degree, flow rate at 1.3 ml/min, wave length at 260 nm and 1 mmol/l phosphate buffer (pH 3.0) as mobile phase. RESULTS: The plasma concentrations of 5-FU were normally distributed in the patients. No adverse effects were noted in the patients with plasma concentration of 5-FU lower than 600 microg/L, and severe toxic side effects were observed in the patients with plasma concentration of 5-FU greater than 1000 microg/L. The differences between plasma concentrations of 5-FU and each grade side effects reached statistical significance (P< 0.05). CONCLUSION: The plasma concentration of 5-FU have highly inter-individual variation in the patients with nasopharyngeal carcinoma. Plasma concentrations of 5-FU were associated with the toxicity and treatment response.

Evidence of a malonyl-CoA-insensitive carnitine palmitoyltransferase I activity in red skeletal muscle.

Carnitine palmitoyltransferase I (CPT I), which is expressed as two distinct isoforms in liver (alpha) and muscle (beta), catalyzes the rate-limiting step in the transport of fatty acid into the mitochondria. Malonyl-CoA, a potent inhibitor of CPT I, is considered a key regulator of fatty acid oxidation in both tissues. Still unanswered is how muscle beta-oxidation proceeds despite malonyl-CoA concentrations that exceed the IC(50) for CPT Ibeta. We evaluated malonyl-CoA-suppressible [(14)C]palmitate oxidation and CPT I activity in homogenates of red (RG) and white (WG) gastrocnemius, soleus (SOL), and extensor digitorum longus (EDL) muscles. Adding 10 microM malonyl-CoA inhibited palmitate oxidation by 29, 39, 60, and 89% in RG, SOL, EDL, and WG, respectively. Thus malonyl-CoA resistance, which correlated strongly (0.678) with absolute oxidation rates (RG > SOL > EDL > WG), was greater in red than in white muscles. Similarly, malonyl-CoA-resistant palmitate oxidation and CPT I activity were greater in mitochondria from RG compared with WG. Ribonuclease protection assays were performed to evaluate whether our data might be explained by differential expression of CPT I splice variants. We detected the presence of two CPT Ibeta splice variants that were more abundant in red compared with white muscle, but the relative expression of the two mRNA species was unrelated to malonyl-CoA resistance. These results provide evidence of a malonyl-CoA-insensitive CPT I activity in red muscle, suggesting fiber type-specific expression of distinct CPT I isoforms and/or posttranslational modulations that have yet to be elucidated.