OBJECTIVE To investigate the stability of 5-fluorouracil （5-FU） in human blood and to establish a standardized clinical sampling and delivery procedure for therapeutic drug monitoring （TDM） of 5-FU. METHODS The EDTA-anticoagulated whole blood was used as the matrix to prepare stability assessment samples of 5-FU at both low （200 ng/mL） and high （5 000 ng/mL） concentrations （with groups without stabilizer and with 1% volume ratio of stabilizer）. The stability assessment samples were placed under room temperature （[ 25±2） ℃] and refrigerated （2-8 ℃） conditions， with sampling at 0， 0.5， 1， 2， 4， 7， and 24 h. After vortexing and centrifugation， the upper plasma layer was collected； proteins were precipitated using methanol， and the concentration of 5-FU in plasma was determined by liquid chromatography-tandem mass spectrometry. Based on the whole blood stability results， clinical sampling and delivery procedures were established. RESULTS The concentration of 5-FU in blank whole blood samples without stabilizers was significantly lower than that in samples with stabilizers （P＜0.05）. However， varying volumes （10， 25， 50 μL） of stabilizers had no significant effect on the measured concentrations of 5-FU in stability assessment samples with low and high concentrations （P＞0.05）. Without the addition of a stabilizer， low- and high-concentration 5-FU whole blood samples remained stable at room temperature for 0.5 h and 1 h， respectively， and under refrigeration for 2 h and 7 h， respectively. After the addition of a 1% stabilizer， the whole blood samples remained stable for up to 24 h under both room temperature and refrigerated conditions. Based on these findings， the following procedure was established： after collection， whole blood samples could be temporarily stored at room temperature （≤0.5 h） or at 4　℃ （≤2 h）， and transported at 2-8　℃. Upon delivery to the laboratory， a 1% volume ratio of stabilizer must be added immediately， followed by centrifugation within 24 h. The resulting plasma should be stored at －20 ℃ . CONCLUSIONS 5-FU in whole blood exhibits poor stability at room temperature. Refrigeration at 2-8　℃ slightly improves stability ， but degradation still occurs rapidly. Adding a stabilizer at a 1% volume ratio significantly prolongs the refrigerated storage time. The established sampling and transport procedure for 5-FU TDM innovatively introduces the stabilizer addition step at the laboratory sample reception stage （rather than immediately after blood draw）. This approach ensures analytical quality while offering greater adaptability to real-world clinical sampling conditions， significantly improving practical feasibility.

OBJECTIVETo analyze the genetic data of 30 insertion and deletion polymorphisms (InDel) loci included in an InvestigatorR DIPplex diagnostic kit, and to evaluate the forensic application in ethnic Tibetan population from China.

METHODSBy detecting 226 unrelated individuals with the Investigator(R) DIPplex kit, allelic frequencies and population genetics parameters of the 30 InDels were statistically analyzed and compared with available data derived from other populations from various regions.

RESULTSAfter the Bonferroni correction at a 95% significance level (P=0.0017), no significant departures from the Hardy-Weinberg equilibrium were observed except for the HLD114 locus. Linkage disequilibrium test showed no significant allelic association between all 30 loci after the Bonferroni's correction. The average heterozygosity (Ho) of all loci was 0.4125, the mean discrimination power (DP) was 0.5618, the mean polymorphism information content (PIC) was 0.3280, and the combined discrimination power (TDP) was 0.999999999990. The combined power of exclusion of all loci was 0.987 849 91 in trio cases and 0.94977125 in duo cases. Genetic distance between Tibetan and Han from Beijing was minimum (0.0068) in the 5 populations, while genetic distance between Tibetan and Uygur was maximal (0.0215).

CONCLUSIONMultiplex detection has revealed that these 30 InDel loci have a moderate distribution of genetic polymorphism among ethnic Tibetan group residing in Tibet, China.

Adult ; Asian Continental Ancestry Group ; ethnology ; genetics ; Female ; Gene Frequency ; Humans ; INDEL Mutation ; Linkage Disequilibrium ; Male ; Middle Aged ; Polymorphism, Genetic ; Tibet ; ethnology ; Young Adult

Objective To research the relation between the time-dependent appearances of myofibroblasts during the repair of contused skeletal muscle in rat and wound age determination. Methods A total of 35 SD male rats were divided into the control and six injured groups according to wound age as fol-lows: 12 h, 1 d, 5 d, 7 d, 10 d and 14 d after injury. The appearances of myofibroblasts were detected by HE staining, immunohistochemistry and confocal laser scanning microscopy. Masson’s trichrome staining was utilized to examine collagen accumulation in the contused areas. Results Immunohistochemical stain-ing showed that α-SMA+ myofibroblasts were initially observed at 5 d post-injury. The average ratio of myofibroblasts was highest at 14 d post-injury, with all samples, ratios more than 50%. In the other five groups, the average of α-SMA positive ratios were less than 50%. The collagen stained areas in the contused zones, concomitant with myofibroblast appearance, were increasingly augmented along with ad-vances of posttraumatic interval. Conclusion The immunohistochemical detection of myofibroblasts can be applied to wound age determination. The myofibroblasts might be involved in collagen deposition during the repair of contused skeletal muscle in rat.

Objective To study the percentages of polymorphonuclear leukocytes (PMN), mononuclear cells (MNC) and fibroblastic cells (FBC) in different post-traumatic intervals after skeletal muscle me-chanical injury in rats. Methods The rat model of skeletal muscle mechanical injury was established. The rats were divided into injured groups (6 h, 12 h, 1 d, 3 d, 7 d, 10 d and 14 d after injury ) and con-trol group. The percentages of PMN, MNC and FBC in different post-traumatic intervals after skeletal muscle mechanical injury were assessed with HE staining and image analysis. Results At post-injury 6-12 h, the percentages of PMN and MNC infiltration appeared in injured sites and that of PMN reached peak. At 1 d, the percentage of MNC infiltration appeared and reached peak, while that of PMN de-creased. At 3-7 d, the percentage of FBC gradually increased, while that of PMN and MNC decreased. At 10-14 d, the percentage of FBC reached peak. Conclusion The percentages of PMN, MNC and FBC in injured zones showed time-dependent changes, which might be used as reference index for determination of age of skeletal muscle injury.

Purpose To explore the effect of Levothyroxine on spatial working memory in patients with subclinical hypothyroidism (SCH) using blood oxygenation level dependent-functional MRI (BOLD-fMRI). Materials and Methods Sixteen patients with SCH before and after 6 months levothyroxine (LT4) treatment and 16 matched euthyroid volunteers underwent n-back task fMRI scanning. AFNI software was used for localization and quantification. Results All the subjects demonstrated activated areas including bilateral dorsolateral prefrontal cortex (DLPFC), bilateral premotor area (PreMA), supplementary motor area/anterior cingulate cortex, bilateral parietal area (PA) and right caudate nucleus/thalamus, with right hemisphere dominance. Quantitative analysis of regions of interests showed that all these regions had load effect related to memory load in the control group (P<0.001), whereas only left DLPFC, left PA, bilateral PreMA and right caudate nucleus/thalamus showed the same effect in SCH group. After 6-month treatment with LT4, BOLD signal change was observed in SCH patients within the right DLPFC, right PA and anterior cingulate/supplementary motor cortex (P<0.001). The activation intensity of working memory related brain regions was lower in SCH group compared with that of the control group. Conclusion Spatial working memory impairments in SCH patients are likely related to decreased right DLPFC and right posterior parietal function. LT4 replacement therapy is important to improve and reverse the memory impairment.