BACKGROUND: Decreasing of absorption of zinc from small intestine can induce dermatitis, alopecia, growth and developmental disorder and so on. It is not very clear that how to keep homeostasis when there is low zinc concentration. The discoveries of zinc transporters and relative researches provide new study direction.OBJECTIVE: To study the effect of different zinc concentration on the expressions of divalent metal transporter 1 (DMT1) and human zinc-regulated transporter (ZRT), iron-regulated transporter (IRT)-like protein (ZIP) 4mRNA, and analyze the potential pathway of absorption of zinc from small intestine in low zinc concentration.DESIGN: Blank-controlled experiment.SETTING: Department of Military Hygiene, Navy Faculty, Second Military Medical University of Chinese PLA.MATERIALS: The experiment was accomplished in Department of Military Hygiene, Navy Faculty of Second Military Medical University of Chinese PLA between October 2004 and May 2005. Materials were human colon adenocarcinoma cells Caco2 that were purchased from Shanghai Institute of Cell of Chinese Academy of Sciences.Time-dependent effect: The expression of DMT1 and ZIP4 mRNA was detected with reverse transcription-polymerase chain reaction (RT-PCR) at 0,dependent effect: The expression of DMT1 and ZIP4 mRNA were measured after the 0, 2.5, 5, 7.5 and 10 μmol/L TPEN exposure, respectively, by RT-PCR.MAIN OUTCOME MEASURES: Time-and dose-dependent effect of zinc on the expression of DMT1 and ZIP4 mRNA in Caco2 cells.RESULTS: ①Time-dependent effect: Compared with 0 hour, the expression of DMT1 mRNA obviously increased at 6, 8 and 10 hours (P ＜ 0.05 ), but there was no significant change at 2 and 4 hours. The expression of ZIP4 mRNA markedly increased in all timing, and ZIP4 mRNA level at the 6th hour reached the peak with the prolongation of low zinc duration,which was 2.1 times ofthat at 0 hour. ②Dose-dependent effect: The expression of DMT1 mRNA distinctly increased at the concentration of 7.5 and 10 μmol/L TPEN exposure as compared with that of the control group (P ＜ 0.05), but there was no significant change at 2.5 and 5 μmol/L. The ZIP4 mRNA expression increased with the increasing of the concentration of TPEN, the expression of ZIP4 mRNA was 2.7 times of that at 0 μmol/L. CONCLUSION: Zinc can regulate the expression of DMT1 and ZIP4 mRNA in Caco2 cells, and there is time-and dose-dependent effect. But the mRNA expression of ZIP4 is more sensitive and prompt than DMT1. Cells can upregulate the expression of DMT1 and ZIP4 mRNA to keep the homeostasis in low zinc condition.

Objective:To observe the growth and development of the weaned mice fed with different levels of dietary zinc and to explore the expression of zinc transporter 3(ZnT3) mRNA induced by different dietary zinc intakes. Methods: Twenty male weaned mice (postnatal day 21) were divided into 4 groups: zinc deficient (ZD), zinc adequate(ZA), zinc supplemental (ZS) and pair fed(PF). Mice were fed with different levels of dietary zinc for 3 weeks (from postnatal day 21 to postnatal day 42) ;the zinc contents of ZD, ZA, ZS and PF group were 1 mg/kg, 30 mg/kg, 180 mg/kg and 180 mg/kg respectively. From postnatal day 21 to postnatal day 42, the diet intakes and weight of the mice were measured everyday. On postnatal day 42, the mice were sacrificed and tissues were immediately isolated and frozen lor RNA extraction. The serum zinc concentrations were measured by AAS and the expression of ZnT3 mRNA was determined by semiquantitative RT-PCR. Results: The dietary intakes and weight of ZD mice were much lower than that of other groups(P3

Objective To explore the expression and change of ski-interacting protein (SKIP) in rats after spinal cord injury. Methods A total of 60 adult female Sprague-Dawley rats were randomly divided into sham group (n=30) and spinal cord injury (SCI) group (n=30), each group was further divided into five time points including one day, three days, five days, seven days, and 14 days with six rats in each time points. The model was established at T10 with modified Allen's technique, and the sham group only bit the lamina of rats. The hindlimbs behavior was assessed with Basso-Beattie-Bresnahan (BBB) score at each time point. The pathological changes of spinal cord neurons were detected with Nissl staining. The expression of SKIP were observed with immunofluorescence staining. Results The BBB scores were signif-icantly lower in each time point in SCI group than in the sham group (t>48.267, P<0.001). Compared with the sham group, Nissl bodies in the cytoplasm of spinal cord neurons began to disintegrate, coalesce and irregularly distribute, the neurons began to degenerate and die on the fifth day, and the damage deteriorated on the 14th day. Immunofluorescence staining showed that SKIP expression was mainly expressed in the gray matter of the spinal cord and little expressed in the white matter. The expression of SKIP gradually increased after SCI, and reached a peak on the fifth day (t=-17.035, P<0.001) and decreased significantly on the 14th day (t=3.853, P<0.05). Conclusion SKIP may be a new signaling molecule, which play an important role in neuronal apoptosis after SCI.

Objective To study the differentiation and proliferation ability of the spinal neural stem cells (NSCs) at different gestational ages in fetal rats. Methods Sprague-Dawley fetal rats were divided into group A (12 days of pregnancy), group B (14 days of pregnancy) and group C (16 days of pregnancy). NSCs were separated with enzyme-assisted microdissection. The diameter and numbers of NSCs balls were measured at different time. The cell growth curve was drawn with CCK8 colorimeter. NSCs were identified with BrdU/Nestin immunohistochemical staining. They were induced with 10% fetal bovine serum for 10 days, and the expression of β-tubulinⅢ and glial fibrillary acidic protein was detected with immunocytochemistry. Results There were cells expressed BrdU, Nestin, β-tubulinⅢ and GFAP in all the group. The most cells (22.74±0.79%) expressed β-tubulinⅢ in the group B, but no significant difference between group B and group C. The cell vitality on the 5th day of third-generation neural stem cells was the most in group B. Conclusion For enzyme-assisted microdissection, it may obtain more neurons to isolate the neural stem cells from 14 days of pregnancy pregnant rats.

Objective To explore the expression and the changes of ski with time in the injured spinal cord in rats. Methods Sixty adult female Sprague-Dawley rats were randomly divided into sham group (n=30) and injury group (n=30), each group were further divided into 1 week, 2 weeks, 4 weeks, 8 weeks and 12 weeks subgroups, with 6 rats in each subgroup. Spinal cord injury at T10 was established with modi-fied Allen's technique (10 g × 25 mm) in the injury group. The hindlimbs behavior of rats was rated with Basso-Beattie-Bresnahan (BBB) scores 1 day, 3 days, 1 week, 2 weeks, 4 weeks, 8 weeks and 12 weeks after spinal cord injury. Three rats in each subgroup were stained with HE staining to observe the pathological changes of the spinal cord and the formation of cavity. The other 3 rats were analyzed with im-munofluorescence staining of ski and semi quantitative analysis. Results The BBB scores of each time point were less in the injury group than in the sham group (P<0.05). Necrosis was the major pathological change in the injury groups 1 and 2 weeks after injury;cystic cavity completely formed 4 weeks after injury, with dense scar tissue around it;there was no significant change in the cavity and scar 8 and 12 weeks after injury, however, the adjacent spinal cord was obviously thinner. Ski expressed little in the normal spinal cord, and expressed more and more after injury, peaked at 8 weeks and decreased then. Ski was mainly observed in white matter in the sham group and 12 weeks injury subgroup, which was in gray matter 2, 4 and 8 weeks after injury. Ski was highly expressed around the cavity in injury center and formed high expression band. Conclusion Ski expresses after spinal cord injury in rats, that may be associated with the activation and prolif-eration of astrocytes and the formation of glial scar.

Objective To explore the learning and memory impairment and pathology in hippocampus in rats after spinal cord contu-sion. Methods 36 adult female Sprague-Dawley rats were randomly divided into sham group (n=18) and spinal cord injury group (n=18). Spinal cord injury model at T10 was established with modified Allen's technique (10 g × 25 mm). The hindlimbs behavior of rats was rated with Basso-Beattie-Bresnahan (BBB) scores once a week for 5 weeks. They were tested with motor evoked potentials (MEP) and Morris wa-ter maze 5 weeks after injury. The pathology of hippocampus was detected with HE staining 1 week, 3 weeks and 5 weeks after injury, 4 rats in a group, repectively. Results The BBB scores were significantly lower in the spinal cord injury group than in the sham group at each time point (P<0.05). The latencies of both N1 and P1 wave of MEP were significantly longer in the spinal cord injury group than in the sham group (P<0.001), while the amplitudes were significantly less (P<0.001). For the Morris water maze, the latency of arrival platform were sig-nificantly longer in the spinal cord injury group than in the sham group (P<0.001), and the time in target was significantly less (P<0.001), with more systematic positioning or annular positioning, while the sham group with more space-based positioning. Morphologically abnor-mal cells in hippocampus gradually increased since the first week after injury, with the decrease of cells survival, while it was normal in the sham group. Conclusion Spinal cord contusion can cause learning and memory impairment in rats, which may be related to injury in hippo-campus.

Objective:To analyze the influencing factors of contrast agent extravasation in coronary CT angiography(CTA)examination,and to formulate intervention measures.Methods:A retrospective selection of data from 583 patients who underwent coronary CTA at Peking University People's Hospital from January to December 2023 was conducted.Logistic regression was used to analyze the patients'general information and injection protocols,and the risk factors of contrast agent extravasation were determined.Results:Among the 583 patients included,11 patients had contrast agent extravasation during CTA examination,with an extravasation rate of 1.887%.The contrast agent was all extravasated into the subcutaneous tissue,and the CT value did not reach the trigger criteria.Gender,education level,diabetes mellitus,history of intravenous chemotherapy,age,weight,body mass index(BMI),injection rate and injection dose were all associated with the occurrence of contrast agent extravasation,the difference was statistically significant(x2=18.911,7.563,16.567,4.279,t=3.576,3.244,1.865,4.297,6.532,P<0.05).Age,education level,history of intravenous chemotherapy,diabetes mellitus,injection rate and injection dose were risk factors for contrast agent extravasation in coronary CTA(OR=1.008,1.372,1.029,5.092,0.975,1.421,P<0.05).Conclusion:Factors such as low education level,advanced age,history of intravenous chemotherapy,high injection rate and large injection dose can increase the risk of contrast agent extravasation in coronary CTA examination.Radiology staff should closely monitor high-risk patients,strengthen monitoring of intravenous injection of contrast agents for coronary CTA examination,and reduce the occurrence of contrast agent extravasation.

Objective To study the effect of active respiratory circulation combined with incremental resistance exercise on exercise endurance in elderly patients with rheumatic heart disease.Methods A total of 120 elderly patients with rheumatic heart disease hospitalized in the cardiac rehabilitation department of this hospital from October 2021 to October 2022 were selected as the study subjects and divided into the observa-tion group and control group by the random number table method,60 cases in each group.The patients in the control group were treated with the conventional treatment and rehabilitation nursing,and the observation group adopted the active respiratory circulation technique combined with incremental resistance exercise on the basis of the former.The 30 s arm flexion,2 min step test,6 min walking distance,cardiac function and nursing satisfaction on 1 d before training and 30 d after training were compared between the two groups.Re-sults The number of 30 s arm flexions and 2 min steps on 30 d after training in the observation group was higher than that in the control group[32.23(12.88,52.33)times vs.23.46(1.77,44.48)times,(9.62±0.48)times vs.(9.03±0.35)times],the 6-min walking distance was longer than that in the control group[(427.59±20.36)m vs.(394.89±17.95)m],the levels of LVEF and BNP were higher than those in the con-trol group[(56.32±3.60)％vs.(52.23±3.13)％,(645.00±9.12)pg/mL vs.(637.00±9.16)pg/mL],and the proportion of very satisfaction was higher than that in the control group(78.33％vs.21.66％),the differ-ences were statistically significant(P＜0.05).Conclusion Active respiration and circulation technology com-bined with incremental resistance exercise could effectively improve the flexion mobility ability of both upper limbs,the flexibility and exercise ability of both lower limbs,and improve the muscle strength of the limbs and cardiac function in elderly patients with rheumatic heart disease.