Estradiol enhances T-type calcium channel activation in human myometrium telocytes.

Uterine peristalsis is essential for gamete transport and embryo implantation. It shares the characteristics of spontaneity, rhythmicity, and directivity with gastrointestinal peristalsis. Telocytes, the "interstitial Cajal-like cells" outside the digestive canal, are also located in the uterus and may act as pacemakers. To investigate the possible origin and regulatory mechanism of periodic uterine peristalsis in the human menstrual cycle, telocytes in the myometrium were studied to determine the effect of estradiol on T-type calcium channel regulation. In this study, biopsies of the human myometrium were obtained for cell culture, and double-labeling immunofluorescence screening was used to identify telocytes and T-type calcium channel expression. Intracellular calcium signal measurements and patch-clamp recordings were used to investigate the role of T-type calcium channels in regulating calcium currents with or without estradiol. Our study demonstrates that telocytes exist in the human uterus and express T-type calcium channels. The intracellular Ca2+ fluorescence intensity marked by Fluo-4AM was dramatically decreased by NNC 55-0396, a highly selective T-type calcium channel blocker, but enhanced by estradiol. T-type calcium current amplitude increased in telocytes incubated with estradiol in a dose-dependent manner compared to the control group. In conclusion, our study demonstrated that telocytes exist in the human myometrium, expressing T-type calcium channels and estradiol-enhanced T-type calcium currents, which may be a reasonable explanation for the origin of uterine peristalsis. The role of telocytes in the human uterus as pacemakers and message transfer stations in uterine peristalsis may be worth further investigation.

Determination, Isolation, and Identification of Related Impurities in Erdosteine Bulk Drug.

BACKGROUND: Erdosteine is a mucolytic drug and has antioxidant activity. OBJECTIVE: The study aimed to develop an HPLC method for determination of erdosteine and its impurities in erdosteine bulk drug and to identify the main impurities to help improve the quality of erdosteine bulk drug. METHOD: The chromatographic separations were performed on a CAPCELL PAK C18 column (250 mm × 4.6 mm id, 5 µm). Acetonitrile-0.01 mol/L citric acid solution (13 + 87, by volume) pumped at a flow rate of 1.0 mL/min was used as the mobile phase. The detection wavelength was 254 nm. Two main impurities in erdosteine bulk drug were enriched by an ODS column chromatography and oxidative degradation, respectively, and then both were purified by semipreparative HPLC. Finally, their structures were identified by a variety of spectral data (MS, 1H NMR and 13C NMR). RESULTS: Good separations of erdosteine and its related impurities were observed. A new impurity was confirmed as ethyl ({2-oxo-2-[(2-oxotetrahydro-3-thiophenyl) amino] ethyl} sulfanyl)acetate, which was erdosteine ethyl ester, and was produced in the refining process of erdosteine bulk drug when using ethanol as a refining solvent. Another impurity was confirmed as ({2-oxo-2-[(2-oxotetrahydro-3-thiophenyl)amino]ethyl}sulfinyl) acetic acid, which was an erdosteine oxide. CONCLUSIONS: An HPLC method for determination of erdosteine and its related impurities was developed and validated. Two main impurities in erdosteine bulk drug were isolated and identified. Avoiding ethanol as the refining solvent can improve the purity of erdosteine bulk drug. HIGHLIGHTS: A new process-related impurity and an oxidative degradation impurity in erdosteine bulk drug were isolated and identified.

Identification and quantification of five impurities in cloperastine hydrochloride.

Cloperastine hydrochloride, a piperidine derivative, is a drug substance with a central antitussive effect and widely used in cough treatment; and its impurities have not been reported. Herein we isolated and identified five impurities (named as impurity A, B, C, D and E) in cloperastine hydrochloride bulk drug and developed a quantitative HPLC method. First, impurity A, B, C were enriched by ODS column chromatography and isolated by semi-preparative HPLC, at the same time, impurity D was purified by ODS column chromatography. Then, impurity E was enriched by strong acid degradation and purified by semi-preparative HPLC. At last, their structures were characterized by a variety of spectral data (MS, 1H NMR, 13C NMR, HSQC, HMBC and 1H-1H COSY). Impurity A was confirmed as 1-[2-(diphenylmethoxy)ethyl]piperidine, which having one less chloro-substituent compared with cloperastine. Impurity B was confirmed as 1-[2-[(2-chlorophenyl)(phenyl)methoxy]ethyl]piperidine, which was the isomer of cloperastine with 2-chloro-substituent. Impurity C was confirmed as 1-[2-[(3-chlorophenyl)(phenyl)methoxy]ethyl]piperidine, which was the isomer of cloperastine with 3-chloro-substituent. Impurity D was confirmed as (4-chlorophenyl)(phenyl)methanone, which was the raw material for the synthesis of cloperastine. Impurity E was confirmed as (4-chlorophenyl)(phenyl)methanol, which was an intermediate in the synthesis of cloperastine, and it was also a hydrolysate of cloperastine. Finally, the developed method was validated in terms of specificity, linearity, sensitivity, precision and accuracy.

A risk model to predict severe postpartum hemorrhage in patients with placenta previa: a single-center retrospective study.

BACKGROUND: The study aimed to establish a predictive risk model for severe postpartum hemorrhage in placenta previa using clinical and placental ultrasound imaging performed prior to delivery. METHODS: Postpartum hemorrhage patients were retrospectively enrolled. Severe postpartum hemorrhage was defined as exceeding 1,500 mL. Data collected included clinical and placental ultrasound images. RESULTS: Age of pregnancy, time of delivery, time of miscarriage, history of vaginal delivery, gestational weeks at pregnancy termination, depth of placenta invading the uterine muscle wall were independent risk factors for severe postpartum hemorrhage in placenta previa. A model to predict severe postpartum hemorrhage in placenta previa was established: P=Log(Y/1-Y), where Y =-6.942 + 0.075 X1 (age) +1.531 X2 (times of delivery) + 0.223 X3 (time of miscarriage) - 3.557X4 (vaginal delivery: 1 for yes, 0 for no) + 1.753 X5 (0 for <37 weeks, 1 for ≥37 weeks) + 1.574 X6 (Depth of placenta invading uterine muscle wall: 0 for normal, 1 for placenta adhesion, 2 for placenta implantation, 3 for placenta penetration); discriminant boundary value of the prediction model (probability: P) was 0.268. Predicting sensitivity (Se) =0.765 (negative predicting accuracy rate), specificity (Sp) =0.900 (positive predicting accuracy rate), total accuracy rate =0.8000, and AUC of ROC curve =0.840. CONCLUSIONS: The risk prediction model which had clinical and ultrasound imaging information prior to delivery had a high decision accuracy. However, before it can be used in the clinic, multicenter large-sample clinical studies should be performed to verify its accuracy and reliability.

A dual-regulated oncolytic adenovirus carrying TAp63 gene exerts potent antitumor effect on colorectal cancer cells.

The purpose of this study is to evaluate possible antitumor activity of a dual-regulated oncolytic adenovirus carrying the TAp63 gene on colorectal cancer. The recombinant virus Ad-survivin-ZD55-TAp63 was constructed by inserting the TAp63 gene into the dual-regulated pshuttle-survivin-ZD55 vector. RT-PCR and western blot assays were used to verify the recombinant virus Ad-survivin-ZD55-TAp63. Crystal violet staining was carried out to detect the cytopathic effect of Ad-survivin-ZD55-TAp63 in human colorectal cancer cell line HCT-116 and normal liver cell line L-O2. MTT and cell apoptosis assays were applied to explore the biological functions of Ad-survivin-ZD55-TAp63 within HCT116 cells. To further identify the antitumor effects of Ad-survivin-ZD55-TAp63 on HCT116 xenograft in BALB/C nude mice, tumor volumes were calculated and tumor tissues from the xenograft models were examined by TUNEL assays. The results showed that Ad-survivin-ZD55-TAp63 was successfully constructed, and could selectively replicate in HCT116 cells without significant toxicity to L-02 cells. Furthermore, Ad-survivin-ZD55-TAp63 dose- and time-dependently inhibited cell proliferation and induced cell apoptosis in vitro. In HCT116 xenograft models, intratumoral injection of Ad-survivin-ZD55-TAp63 significantly suppressed tumor growth and caused tumor cell apoptosis. Therefore, these results suggest that the recombinant virus Ad-survivin-ZD55-TAp63 exhibits specific antitumor effects, and may be used in the future for the treatment of colorectal cancer.

Soil respiration and carbon loss relationship with temperature and land use conversion in freeze-thaw agricultural area.

Soil respiration (Rs) was hypothesized to have a special response pattern to soil temperature and land use conversion in the freeze-thaw area. The Rs differences of eight types of land use conversions during agricultural development were observed and the impacts of Rs on soil organic carbon (SOC) loss were assessed. The land use conversions during last three decades were categorized into eight types, and the 141 SOC sampling sites were grouped by conversion type. The typical soil sampling sites were subsequently selected for monitoring of soil temperature and Rs of each land use conversion types. The Rs correlations with temperature at difference depths and different conversion types were identified with statistical analysis. The empirical mean error model and the biophysical theoretical model with Arrhenius equation about the Rs sensitivity to temperature were both analyzed and shared the similar patterns. The temperature dependence of soil respiration (Q10) analysis further demonstrated that the averaged value of eight types of land use in this freeze-thaw agricultural area ranged from 1.15 to 1.73, which was lower than the other cold areas. The temperature dependence analysis demonstrated that the Rs in the top layer of natural land covers was more sensitive to temperature and experienced a large vertical difference. The natural land covers exhibited smaller Rs and the farmlands had the bigger value due to tillage practices. The positive relationships between SOC loss and Rs were identified, which demonstrated that Rs was the key chain for SOC loss during land use conversion. The spatial-vertical distributions of SOC concentration with the 1.5-km grid sampling showed that the more SOC loss in the farmland, which was coincided with the higher Rs in farmlands. The analysis of Rs dynamics provided an innovative explanation for SOC loss in the freeze-thaw agricultural area. The analysis of Rs dynamics provided an innovative explanation for SOC loss in the freeze-thaw agricultural area.

Comparison of three derivatization reagents for the simultaneous determination of highly hydrophilic pyrimidine antitumor agents in human plasma by LC-MS/MS.

A comparison of three derivatization reagents (dansyl chloride, diazomethane and p-bromophenacyl bromide) for the simultaneous quantitation of three anticancer chemicals (tegafur, 5-fluorouracil and gimeracil) and endogenous uracil in plasma using high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed and evaluated. Through a comprehensive consideration, p-bromophenacyl bromide (p-BPB) was finally selected as the derivatization reagent. Because it essentially changed the chromatographic behavior of the aforementioned highly hydrophilic compounds and significantly enhanced their sensitivities. The method was validated over the concentration ranges of 5-5000 ng/ml for tegafur, 0.6-700 ng/ml for 5-fluorouracil, 3-700 ng/ml for gimeracil and 6-2000 ng/ml for uracil. The method was successfully applied to the pharmacokinetics study of tegafur, 5-fluorouracil, gimeracil and uracil in cancer patients.

[Pharmacokinetics of S-1 capsule in patients with advanced gastric cancer].

The study is to investigate the pharmacokinetics of S-1 capsule (tegafur, gimeracil and potassium oxonate capsule) in patients with advanced gastric cancer after single and multiple oral administration. Twelve patients with advanced gastric cancer were recruited to the study. The dose of S-1 for each patient was determined according to his/her body surface area (BSA). The dose for single administration was 60 mg every subject. The dose for multiple administration for one subject was as follows: 100 mg x d(-1) or 120 mg x d(-1), 28-days consecutive oral administration. The pharmacokinetic parameters of tegafur, 5-fluorouracil, gimeracil, potassium oxonate and uracil after single oral administration were as follows: (2,207 +/- 545), (220.0 +/- 68.2), (374.9 +/- 103.0), (110.5 +/- 100.8) and (831.1 +/- 199.9) ng x mL(-1) for Cmax; (11.8 +/- 3.8), (4.4 +/- 3.3), (7.8 +/- 5.1), (3.1 +/- 0.9) and (8.8 +/- 4.1) h for t1/2, respectively. After six days oral administration, the average steady state plasma concentrations (Cav) of tegafur, 5-fluorouracil, gimeracil, potassium oxonate and uracil were (2,425 +/- 1,172), (73.88 +/- 18.88), (162.6 +/- 70.8), (36.89 +/- 29.35) and (435.3 +/- 141.0) ng x mL(-1), respectively, and the degree of fluctuation (DF) were (1.0 +/- 0.2), (2.5 +/- 0.4), (3.1 +/- 0.8), (2.4 +/- 0.8) and (1.5 +/- 0.3), respectively. The cumulative urine excretion percentage of tegafur, 5-fluorouracil, gimeracil and potassium oxonate in urine within 48 h were (4.2 +/- 2.8) %, (4.7 +/- 1.6) %, (18.5 +/- 6.0) % and (1.7 +/- 1.2) %, repectively, after single oral administration of S-1. The results exhibited that tegafur had some drug accumulation observed, and gimeracil, potassium oxonate, 5-fluorouracil and uracil had no drug accumulation observed.