Three-dimensional digital measurement of the facet joint in normal individual and lumbar intervertebral disc herniation patients aged 13 - 18 years.

BACKGROUND: Lumbar facet joint is an important element of spinal "three-joint complex". Whether there is a relationship between strange structure of facet joint and adolescent lumbar disc herniation (ALDH) is nonetheless controversial, and the current research is mainly centered on adults. OBJECTIVE: To find out the normal lumbar facet joints between 13 and 18 years old to provide anatomical basis for early diagnosis and therapy of lumbar disc herniation. METHODS: CT imaging information of 32 sufferers with lumbar disc herniation aged from 13 to 18 years old in Inner Mongolia have been collected as the ALDH group, and 62 wholesome subjects in the equal period had been chosen as the normal group. Uncooked records of continuous scanning lumbar tomography pix were imported into MIMICS 21.0 for evaluation and size in DICOM format. The parameters include facet joint height, facet joint width, et al. RESULTS: 1. The left and right transverse angle of L5S1 segment in the ALDH group were (52.41 ± 9.2) ° and (55.99 ± 10.91) ° (P < 0.05), and the differences were statistically significant. The right side is larger than the left side. 2. Facet joint thickness in L3-L5 segment of the normal group was significantly higher than that of male (1.63 ± 0.32) mm than that of female (1.38 ± 0.25) mm; In 16-18 years old group, comparison of facet joint cross-sectional area was statistically significant (22.1 ± 3.04) mm2 in male than (18.92 ± 3.71) mm2 in female. 3. In comparison between normal and ALDH group, there was significant difference in L3-4 transverse angle (P < 0.05), L4-5 facet joint height and facet joint thickness (P < 0.05), L5S1 facet joint thickness and transverse angle (P < 0.05). CONCLUSION: When ALDH occurs in the L5S1 segment, there is a substantial difference between the left and right sides of the transverse angle, and there is a difference in the thickness and the facet joint cross-sectional area between males and females, which is generally larger in males than in females. Facet joint height is larger, transverse angle of left and right is asymmetric, inferior articular process is larger, and facet joint thickness is smaller can indicate that lumbar disc herniation is effortless to occur.

UHPLC-MS/MS Determination, Pharmacokinetic, and Bioavailability Study of Taxifolin in Rat Plasma after Oral Administration of its Nanodispersion.

A rapid and sensitive LC-MS/MS method based on the Triple Quad system has been developed and validated for the determination and pharmacokinetics of taxifolin and its nanodispersion in rat plasma. Taxifolin plasma samples along with butylparaben (internal standard) were pre-treated by liquid-liquid extraction with ethyl acetate, and then separated on a SB-C18 RRHD column (150 mm × 2.1 mm × 1.8 µm) using isocratic elution with a run time of 3.0 min. The mobile phase was acetonitrile-water (90:10, v/v) containing 5 mM ammonium acetate at a flow rate of 0.4 mL/min. Quantification of taxifolin was performed by the electrospray ionization tandem mass spectrometry in the multiple reaction monitoring (MRM) mode with negative atmospheric ionization at m/z 303.0→285.0 for taxifolin and 193.1→92.0 for I.S., respectively. The calibration curve of taxifolin showed good linearity over a concentration range of 5.0-4280 ng/mL with a correlation coefficient of 0.9995. The limit of quantification (LLOQ) was 5.0 ng/mL. Intra-day, inter-day precision and accuracy (percent relative to standard deviation) were all within 8% at three concentration levels. A total recovery of taxifolin and I.S. was beyond 75%. The present LC-MS/MS method was successfully applied to pharmacokinetic studies of taxifolin after intravenous administration of taxifolin, oral administration of its physical mixture and nanodispersion. The absolute bioavailability of taxifolin was calculated as 0.75% for taxifolin nanodispersion and 0.49% for taxifolin, respectively.

Stereoselectivity in metabolic 3-reduction of tibolone in healthy Chinese female volunteers.

AIM: To investigate the stereoselectivity in human metabolic 3-reduction of tibolone. METHODS: Twenty healthy Chinese female volunteers were given a single oral dose of tibolone (2.5 mg), and serial blood samples were collected after treatment. The plasma concentrations of the two pharmacologically active 3-hydroxyl metabolites of tibolone, 3alpha-hydroxyl-7-methyl- norethynodrel (3alpha-HMN) and 3beta-hydroxyl-7-methyl- norethynodrel (3beta-HMN) in plasma were determined by using a validated liquid chromatography-mass spectrometry (LC-MS) method. RESULTS: The apparent elimination half-life (T(1/2) of 3alpha-HMN was 1.43+/-0.52 h, and that of 3beta-HMN was 1.53+/-0.60 h. Maximum plasma concentrations (C(max)) were found to be 8.75+/-4.36 microg/L for 3alpha-HMN and 3.59+/-1.81 microg/L for 3beta-HMN. Areas under the plasma concentration versus time curve (AUC(0-t)) were 26.30+/-12.14 microg.h(-1).L(-1) for 3alpha-HMN and 9.89+/-4.93 microg.h(-1).L(-1) for 3beta-HMN. CONCLUSION: Stereo-selective differences exist in the pharmacokinetics of tibolone metabolism in humans.

p-Toluenesulfonyl isocyanate as a novel derivatization reagent to enhance the electrospray ionization and its application in the determination of two stereo isomers of 3-hydroxyl-7-methyl-norethynodrel in plasma.

In this paper, p-toluenesulfonyl isocyanate has been reported as a novel derivatization reagent with strong nuclephilic reactivity for the hydroxyl compounds. The derivatization for the two pharmacologically active 3-hydroxyl metabolites, 3alpha-hydroxyl-7-methyl-norethynodrel and 3beta-hydroxyl-7-methyl-norethynodrel by p-toluenesulfonyl isocyanate can be accomplished in 2 min under room temperature. The offline derivatization procedure introduced an easily ionizable sulfonylcarbamic ester moiety to the metabolites. This greatly improved the analyte's sensitivity in negative electrospray ionization and enabled us to achieve the desired lower limit of quantitation at 100 pg/ml in plasma. Therefore, a sensitive high performance liquid chromatography-mass spectrometry (HPLC-MS) method for the analysis of the two stereo isomers was developed. The method had been validated to be accurate, precise, and sensitive, and can be used for the metabolism pharmacokinetic study of tibolone in human subjects.