[Consistency evaluation of 2 methods in detecting serum insulin-like growth factorâ in children].

Objective: To evaluate the consistency of mass spectrometry (MS) and chemiluminescence immunoassay (CLIA) in detecting serum insulin-like growth factor-1 (IGF-1) and IGF-1 standard deviation score (SDS). Methods: This cross-sectional parallel control study prospectively collected the serum samples of 115 children with short stature disorders who were admitted in the Department of Endocrinology, Beijing Children's Hospital, Capital Medical University from February 2020 to December 2021. The serum IGF-1 level was detected by CLIA and MS, and converted to SDS for consistency analysis. Pearson analysis was used to analyze the correlation between the 2 methods, and Deming regression equation was established. Bland-Altman diagram and weighted Kappa coefficient were used to evaluate the consistency of the 2 methods. Results: There were 46 boys (40.0%) and 69 girls (60.0%), aged (8±3) years. Among the 115 cases, 37 were Turner syndrome, 59 were small for gestational age (SGA) at term, 1 was growth hormone deficiency (GHD) and 18 were other diseases. Pearson correlation analysis showed a preferable correlation between IGF-1 measured by the 2 detection methods (r=0.94, P<0.01), and IGF-1 SDS was also significantly correlated (r=0.92, P<0.01). Bland-Altman analysis showed that the consistency of serum IGF-1 levels detected by the 2 methods was poor, and the mean difference between CLIA and MS was 33.38 µg/L. The result detected by CLIA was significantly higher than that by MS, with SDS of 43.51 µg/L (95%CI -51.89-118.7 µg/L). After converting the results to SDS and removing 3 outliers (including 1 GHD patient), the weighted Kappa showed acceptable consistency (κ=0.68). Conclusion: In clinical application, after converting to IGF-1 SDS, IGF-1 detected by MS and CLIA can be used for cross-reference, but too high or too low levels should be cautious about.

[Clinical characteristics of 14 cases of neonatal tracheotomy in neonatal intensive care unit].

Objective: To analyze the clinical characteristics of neonatal tracheotomy in neonatal intensive care unit (NICU). Methods: This single-center retrospective study included 14 neonates admitted to NICU of Beijing Children's Hospital, Capital Medical University from January 2016 to August 2021, and were<28 days of age on admission, who met the criteria of tracheotomy and finally completed the procedure. The clinical characteristics including age, weight, duration of ventilation, etiology of tracheotomy, length of hospital stay and prognosis were summarized and analyzed. Wilcoxon signed-rank test was used to compare the weight gain velocity and the duration of ventilation before and after tracheotomy. Paired t-test was used to compare the hospitalization length before and after tracheotomy. Spearman correlation was used to analyze the correlation between the clinical characteristics and outcomes. Results: For the 14 neonates, the gestational age was (38±4) weeks and birth weight was (2 824±949) g. Nine of them were male. The age on transportation was 16 (6, 25) d. A total of 10 neonates were on invasive ventilation on admission, the other 4 were on nasal continuous positive airway pressure support. Bilateral vocal cord paralysis (7 cases) was the commonest cause of tracheotomy. The age on operation was 33 (22, 44) d. There were statistically significant differences in duration of ventilation and weight gain velocity before and after operation (19.00 (10.50, 34.00) vs. 0.86 (0.06, 3.25) d, 1.66 (-0.16, 5.54) vs. 4.69 (2.30, 9.32) g/(kg·d), Z=3.01 and -1.98, both P<0.05). The total hospital stay in NICU was (37±12) d. One neonate died during hospitalization. The existence of pneumonia on admission was positively correlated to NICU stay length (r=0.57, P=0.027), the pre-operational weight gain velocity was negatively correlated to the post-operational NICU stay length (r=-0.73, P=0.020). There were 4 neonates de-cannulated during 7-38 months after the tracheotomy, and 5 neonates still wearing the tracheal cannulation during 15-66 months after the tracheotomy. Two neonates died and 2 neonates lost follow-up after discharge. All neonates could not vocalize normally before de-cannulation, and the language development obviously lagged behind the normal age group after de-cannulation. Conclusions: Bilateral vocal cord paralysis is the commonest cause of neonatal tracheotomy. The benefit of tracheotomy for NICU neonates with surgical indications is obvious, especially in facilitating extubation and improving weight gain.

[Development of case report form based on clinical data interchange standards consortium on special diseases to promote the ecology construction of real-world data in China].

Real world data (RWD) refers to the data generated in routine clinical practices, daily life, and real work environment and has been widely used in clinical or public health research. Still, issues related to the quality of RWD, such as incompleteness, inconsistency, and inaccuracy, would affect the validity of real-world research. To overcome the challenges due to the lack of standardization of real world source data, case report form based on clinical data interchange standards consortium (CDISC-CRF) on certain diseases was developed to promote the ecology construction of RWD based on the data standards set by the CDISC which has been widely used. Firstly, we described how to apply data standards to make up the gap between RWD and real world evidence. Then, the process was designed to build RWD ecology based on CDISC-CRF, in which the development technology of CDISC-CRF form is mainly introduced. Finally, the application prospect and significance of building real-world data based on disease-specific CDISC-CRF are described. It is believed that the present paper can provide a new idea for promoting the ecology construction of RWD in China.

[Establishment of reference interval of vitamin A for Chinese children and adolescents based on expectation-maximization algorithm].

Objective: To establish the reference interval of vitamin A for Chinese children and adolescents by indirect approach. Method: The serum retinol samples from 28 provinces, autonomous regions and municipalities in China between January 2016 and June 2019 were examined by high performance liquid chromatography in third-party clinical laboratory institutions. Using a cross-sectional study, descriptive statistics of serum vitamin A levels in children and adolescents aged 0-18 years were carried out in population, region and season. The distribution parameters of vitamin A levels were calculated iteratively by the expectation-maximization (EM) algorithm, and the reference interval was established. Results: A total of 1 096 597 cases were included in the analysis, including 631 017 males and 465 580 females, with a median age of 3(1, 6) years. Before the age of 4 years, the median serum vitamin A level increased with age [median level and its quartiles was 0.15 (0.11, 0.18) mg/L for neonates, 0.23 (0.18, 0.29) mg/L for infants aged below 1 year, and 0.27 (0.20, 0.34) mg/L for kids aged 1-<4 years]. The median serum vitamin A level was stable at the age of 4-8 years (median level ranged from 0.27 to 0.29 mg/L). Afterwards, the median serum vitamin A level reached 0.30 mg/L at the age of 9 years, and then an increasing trend with age was observed till 18 years. The median serum vitamin A level was higher in south area (male:0.33 mg/L; female:0.34 mg/L), compared with other areas (0.24-0.30 mg/L). The variation of the median serum vitamin A level among seasons was within 0.03 mg/L. Based on EM algorithm using indirect approach, the reference intervals of vitamin A for Chinese children and adolescents were as follows: newborn, 0.27-0.47 mg/L; infants aged below 1 year, 0.36-0.56 mg/L; children aged 1-<7 years, 0.35-0.54 mg/L; children aged 7-<16 years, 0.46-0.60 mg/L; and teenagers aged over 16 years, 0.38-0.59 mg/L. Conclusion: The EM algorithm can provide a basis for the establishment of vitamin A reference interval for Chinese children and adolescents, and the established reference interval needs to be further verified by direct method.

[Visual outcome of cataract surgery and its influencing factors in China].

Objective: To explore the visual outcome of cataract surgery and its influencing factors in China. Methods: A case-control study. The information of 2 078 479 patients who underwent cataract extraction of 31 provinces (municipalities and autonomous regions) recorded in the National Cataract Surgery Information Reporting System during January to December, 2017 were analyzed. The postoperative visual outcomes of 3 days after surgery and 3 months after surgery were analyzed. The effects of age, gender, preoperative corrected visual acuity, past medical history, and surgical methods on the results of cataract surgery were analyzed. Surgery effect was divided into ideal effect, moderate effect and poor effect according to the best corrected visual acuity after operation. Wilcoxon rank sum test and multinomial logistic regression model were used for statistical analysis. Results: There were 1 197 942 female patients (57.64%) and 880 537 male patients (42.36%) in all 2 078 479 cases. The average age was (69±11) years old. The main type of cataract was age-related (1 928 440 cases; 92.78%). There were 1 608 385 cases, 1 126 961 cases and 389 020 cases with complete corrected visual acuity before surgery, 3 days after surgery and 3 months after surgery, respectively. The median difference of corrected visual acuity of preoperative versus three days after surgery, and preoperative versus three months after surgery were -0.48, -0.52 respectively (after logarithm of the minimum angle of resolution conversion). The interquartile ranges were 0.60 and 0.73 respectively. The differences were statistically significant (Z=551 599.30, 206 815.35; both P<0.01). Multivariate analysis showed that postoperative complications (moderate effect: OR=0.50, 95%CI: 0.46 to 0.55; ideal effect: OR=0.31, 95%CI: 0.28 to 0.33), preoperative pupil abnormal (moderate effect: OR=0.52, 95%CI: 0.44 to 0.61; ideal effect: OR=0.55, 95%CI: 0.47 to 0.63), preoperative intraocular pressure abnormalities (moderate effect: OR=0.86, 95%CI: 0.79 to 0.93; ideal effect: OR=0.45, 95%CI: 0.42 to 0.49), history of hypertension (moderate effect: OR=0.90, 95%CI: 0.85 to 0.95; ideal effect: OR=0.88, 95%CI: 0.83 to 0.93) and history of diabetes (moderate effect: OR=0.86, 95%CI: 0.80 to 0.93; ideal effect: OR=0.92, 95%CI: 0.86 to 0.99) were predictors of worse outcome. Good preoperative corrected visual acuity (0.2 to 0.4 for moderate effect: OR=2.20, 95%CI: 2.06 to 2.34; for ideal effect: OR=5.25, 95%CI: 4.94 to 5.59; 0.5 to 0.7 for moderate effect: OR=1.08, 95%CI: 0.96 to 1.21; for ideal effect: OR=6.35, 95%CI: 5.69 to 7.08; above 0.8 for moderate effect: OR=0.73, 95%CI: 0.60 to 0.89; for ideal effect: OR=6.58, 95%CI: 5.51 to 7.86), small incision extracapsular extraction (moderate effect: OR=3.19, 95%CI: 2.35 to 4.33; ideal effect: OR=6.79, 95%CI: 5.13 to 8.97) and phacoemulsification (moderate effect: OR=2.12, 95%CI: 1.60 to 2.81; ideal effect: OR=3.34, 95%CI: 2.59 to 4.32) were predictors of better outcome. Conclusions: Visual acuity of patients in China improve significantly after cataract surgery. However, some patients still suffer moderate visual impairment. The effect of surgery can be affected by many factors, such as preoperative corrected visual acuity, preoperative intraocular pressure, preoperative pupil status, surgical approach and postoperative complications, etc. (Chin J Ophthalmol, 2021, 57: 63-70).

[Epidemic characteristics of hand, foot and mouth disease (HFMD) and the lag effect of average daily temperature on the epidemic of HFMD in Beijing].

Objective: To analyze the epidemic characteristics of hand, foot and mouth disease (HFMD) in Beijing and explore the short-term lag effect of daily average temperature on HFMD. Methods: The incidence data and meteorological data of HFMD were collected from Xicheng District, Chaoyang District, and Changping District of Beijing between January 2009 and December 2018. The dose-response relationship and short-term lag effect of temperature and HFMD incidence were explored by the distributed lag non-linear model (DNLM). Results: From 2009 to 2018, a total of 97 210 cases of HFMD were confirmed in Xicheng District, Chaoyang District, and Changping District of Beijing. The incidence rate of HFMD in Xicheng district was 71.83/100 000, which was the lowest in three districts. The total annual average incidence was 146.89/100 000 in the three districts. The cases were concentrated from May to July, with a small peak in October to November. The ratio of male to female was 1.49∶1, and the median age of the patients was 3.08 (1.89, 4.39) years old, which showed a decreasing trend in children under 6 years old (Z=-30.11, P<0.01). The DNLM showed that the cumulative relative risk (RR) curve had a bimodal distribution, with RR of 1.36 (95%CI: 1.05-1.76) and 1.35 (95%CI: 1.10-1.66), and the peak values appeared at 4 ℃ and 26 ℃, respectively. Conclusions: The incidence rate of HFMD in Xicheng was the lowest in three districts of Beijing. In addition, the incidence of HFMD is seasonal, and the incidence is higher in spring and summer than that in autumn and winter. Daily average temperature had a lag effect on HFMD, which was different between high temperature and low temperature.

[Clinical characteristics and gene expression profiles in children with ETV6-RUNX1 acute lymphoblastic leukemia].

Objective: To evaluate the heterogeneity in pediatric ETV6-RUNX1 acute lymphoblastic leukemia (ALL) by gene expression profile and to study clinical characteristics in different clusters. Methods: An improved advanced fragment analysis (iAFA) technique was developed to detect 57 marker genes in 264 pediatric ALL patients treated in Beijing Children's Hospital from August 2016 to June 2019. The 56 ALL patients with ETV6-RUNX1 positive were evaluated by clinical characteristics in gene expression profile, immunophenotype and early response of chemotherapy in different clusters. Results: The 56 ETV6-RUNX1-positive patients were clustered into 2 groups of E/R-1 (45, 80.4%) and E/R-2 (11, 19.6%) . Spearman coefficient was 0.788 and 0.901 in E/R-2 and E/R-1, respectively. The median of initial platelet counts was 104 (27-644) and 50 (8-390) (P<0.01) in E/R-2 and E/R-1, respectively. The median of proportion of initial bone marrow immature cells was 0.830 (0.270-0.975) and 0.935 (0.445-0.990) (P<0.05) in E/R-2 and E/R-1, respectively. The most specific immunophenotype at initial diagnosis, CD22(+)CD34(+)CD20(-)CD117(-)CD56(-), mainly gathered in E/R-2 (P<0.001) . Patients negative of minimal residual disease detected by flow cytometry (MRD-FCM) at day 33 were 5 (55.6%) and 32 (88.9%) in E/R-2 and E/R-1, respectively. There was no significant difference in the original analysis (P=0.064) but difference in sensitivity analysis (P=0.035) . Nevertheless, patients negative of MRD detected by polymerase chain reaction (MRD-PCR) at day 33 were 7 (77.8%) and 36 (100%) in E/R-2 and E/R-1, respectively, with significant difference (P=0.047) . Conclusion: Gene expression profile shows heterogeneous in ETV6-RUNX1 ALL, and the E/R-2 profile indicates that these patients may have a less tendency to thrombocytopenia at the initial diagnosis but have poorer response to induction chemotherapy and may influence further outcome.

Research Note: The immune enhancement ability of inulin on ptfA gene DNA vaccine of avian Pasteurella multocida.

To evaluate the ability of inulin to enhance the immune response of a ptfA gene DNA vaccine for avian Pasteurella multocida, inulin was added as an adjuvant to the ptfA-DNA vaccine, obtaining an inulin-adjuvant DNA vaccine. The DNA vaccine was administered to chickens; a fimbria protein vaccine and an attenuated live vaccine were used as positive controls. The levels of the serum antibody and concentrations of interferon-γ (IFN-γ), interleukin-2 (IL-2), and interleukin-4 (IL-4) were determined, and a lymphocyte proliferation assay was performed. After being challenged with virulent P. multocida, the protective efficacy was evaluated. The results showed that the serum antibodies induced by the ptfA-DNA vaccine were not enhanced by inulin. The stimulation index values and the concentrations of IL-2 and IFN-γ in chickens vaccinated with inulin-adjuvant DNA vaccine were significantly higher than those in chickens vaccinated with the DNA vaccine, those with the fimbria protein vaccine, and the chickens gavaged with inulin. The concentrations of IL-4 in the inulin-adjuvant DNA vaccine group and the fimbria protein vaccine group were higher than those in the DNA vaccine group and the inulin-gavage group. The protective efficacy rates of the attenuated live vaccine group, the fimbria protein vaccine group, the DNA vaccine group, the inulin-adjuvant DNA vaccine group, and the inulin-gavage group were 90, 70, 55, 65, and 55%, respectively.

Columnar structured FePt films epitaxially grown on large lattice mismatched intermediate layer.

The microstructure and magnetic properties of the FePt films grown on large mismatched ZrN (15.7%) intermediate layer were investigated. With using ZrN intermediate layer, FePt 10 nm films exhibited (001) texture except for some weaker FePt (110) texture. Good epitaxial relationships of FePt (001) <100>//ZrN (001) <100>//TiN (001) <100> among FePt and ZrN/TiN were revealed from the transmission electron microscopy (TEM) results. As compared with TiN intermediate layer, although FePt-SiO2-C films grown on ZrN/TiN intermediate layer showed isotropic magnetic properties, the large interfacial energy and lattice mismatch between FePt and ZrN would lead to form columnar structural FePt films with smaller grain size and improved isolation. By doping ZrN into the TiN layer, solid solution of ZrTiN was formed and the lattice constant is increased comparing with TiN and decreased comparing with ZrN. Moreover, FePt-SiO2-C films grown on TiN 2 nm-20 vol.% ZrN/TiN 3 nm intermediate layer showed an improved perpendicular magnetic anisotropy. Simultaneously, columnar structure with smaller grain size retained.

[Intervention of systolic pressure and left ventricular hypertrophy in rats under cold stress].

OBJECTIVE: To investigate the effects of different drugs on systolic blood pressure (SBP) and left ventricular hypertrophy (LVH) in spontaneously hypertensive rats under cold stress. METHODS: A total of 40 male spontaneously hypertensive rats aged 10 weeks (160~200 g) were given adaptive feeding for 7 days at a temperature of 20±1°C and then randomly divided into control group, cold stress group, metoprolol group, amlodipine group, and benazepril group, with 8 rats in each group. SBP, body weight, and heart rate were measured once a week. After the rats were sacrificed by exsanguination, left ventricular weight (LVW) was measured, and left ventricular weight index (LVWI; mg/g) was calculated. Radioimmunoassay was used to measure the concentrations of endothelin-1 (ET-1) and angiotensin-II (Ang-II) in plasma and myocardium, and the chemical method was used to measure the concentrations of nitric oxide (NO) in plasma and myocardium. RT-PCR was used to measure the mRNA expression of endothelin-A receptor. RESULTS: Compared with the cold stress group, all medication groups showed significant reductions in SBP since week 5 (P<0.05). The cold stress group showed a significant increase in LVWI compared with the control group (3.38±0.27 mg/g vs 2.89±0.19 mg/g, P<0.05). The amlodipine group showed a significant reduction in LVWI compared with the cold stress group (2.98±0.28 mg/g vs 3.38±0.27 mg/g, P<0.05). The cold stress group showed a significant reduction in plasma NO concentration compared with the control group (104.9±19.5 µmol/L vs 129.3±17.8 µmol/L, P<0.05) ; compared with the cold stress group, all the medication groups showed significant increases in blood NO concentration (P<0.05). The cold stress group showed a significant increase in myocardial ET-1 concentration compared with the control group (6.3±1.5 pg/100 mg vs 4.5±1.9 pg/100 mg, P<0.05) ; compared with the cold stress group, the amlodipine group showed a significant reduction in myocardial ET-1 concentration (4.4±1.0 pg/100 mg vs 6.3±1.5 pg/100 mg, P<0.05). The cold stress group had significantly higher mRNA expression of endothelin-A receptor than the control group (0.86±0.23 vs 0.45±0.16, P<0.01) ; compared with the cold stress group, the amlodipine group showed a significant reduction in the mRNA expression of endothelin-A receptor (0.41±0.14 vs 0.86±0.23, P<0.01). CONCLUSION: Amlodipine can reduce the increase in SBP and inhibit LVH in spontaneously hypertensive rats under cold stress.

Erythropoietin Pretreatment Attenuates Seawater Aspiration-Induced Acute Lung Injury in Rats.

Seawater drowning-induced acute lung injury (ALI) is a serious clinical condition characterized by increased alveolar-capillary permeability, excessive inflammatory responses, and refractory hypoxemia. However, current therapeutic options are largely supportive; thus, it is of great interest to search for alternative agents to treat seawater aspiration-induced ALI. Erythropoietin (EPO) is a multifunctional agent with antiinflammatory, antioxidative, and antiapoptotic properties. However, the effects of EPO on seawater aspiration-induced ALI remain unclear. In the present study, male rats were randomly assigned to the naive group, normal saline group, seawater group, or seawater + EPO group. EPO was administered intraperitoneally at 48 and 24 h before seawater aspiration. Arterial blood gas analysis was performed with a gas analyzer at baseline, 30 min, 1 h, 4 h, and 24 h after seawater aspiration, respectively. Histological scores, computed tomography scan, nuclear factor kappa B p65, inducible nitric oxide synthase, caspase-3, tumor necrosis factor-alpha, interleukin (IL)-1ß, IL-6, IL-10, wet-to-dry weight ratio, myeloperoxidase activity, malondialdehyde, and superoxide dismutase in the lung were determined 30 min after seawater aspiration. Our results showed that EPO pretreatment alleviated seawater aspiration-induced ALI, as indicated by increased arterial partial oxygen tension and decreased lung histological scores. Furthermore, EPO pretreatment attenuated seawater aspiration-induced increase in the expressions of pulmonary nuclear factor kappa B p65, inducible nitric oxide synthase, caspase-3, tumor necrosis factor-alpha, IL-1ß, myeloperoxidase activity, and malondialdehyde when compared with the seawater group. Collectively, our study suggested that EPO pretreatment attenuates seawater aspiration-induced ALI by down-regulation of pulmonary pro-inflammatory cytokines, oxidative stress, and apoptosis.

Neurobehavioural abnormalities induced by repeated exposure of neonatal rats to sevoflurane can be aggravated by social isolation and enrichment deprivation initiated after exposure to the anaesthetic.

BACKGROUND: We tested the hypothesis that developmental effects of repeated neonatal exposure to sevoflurane in rats are exacerbated by stressful experiences received later in life. METHODS: Sprague-Dawley male rats received sequential exposures to 3% sevoflurane for two h on postnatal days (P) six, seven, and eight. After weaning at P21, rats were housed either in pairs in an enriched environment (EE) or singly in an enrichment-deprived environment (an adverse environment, AE). The hippocampal concentrations of brain-derived neurotrophic factor (BDNF), and synaptic markers were assessed at P8 and P53. The dentate gyrus neural progenitor proliferation was evaluated at P11 and P53 after administration of bromodeoyuridine (BrdU) at P8 to P10 and at P22 to P27, respectively. Neurobehavioural evaluations were performed at P49 to P53. RESULTS: Repeated sevoflurane exposure acutely reduced concentrations of BDNF, synaptic markers and neural progenitor proliferation. The sevoflurane group housed in the AE conditions (sevoflurane+AE) had decreased concentrations of BDNF and synaptic markers, and survival of new granule cells and impaired cognitive function compared with the control+AE, control+EE, and sevoflurane+EE groups. The neurobehavioural parameters in the sevoflurane+EE and control+EE groups were similar. CONCLUSIONS: Neurocognitive abnormalities induced by repeated neonatal exposure to sevoflurane can be aggravated by stressful conditions such as social isolation and enrichment deprivation.

Nanogranular TiN-ZrO2 intermediate layer induced improvement of isolation and grain size of FePt thin films.

The effects of TiN-ZrO2 intermediate layer on the microstructures and magnetic properties of FePt films were investigated. The TiN-ZrO2 intermediate layer was granular consisting of grains of solid solution of Ti(Zr)ON segregated by amorphous ZrO2. By doping ZrO2 into TiN intermediate layer, the FePt grains became better isolated from each other and the FePt grain size was reduced. For 20 vol. % ZrO2 doping into TiN, the grain size decreased dramatically from 11. 2 nm to 6. 4 nm, and good perpendicular anisotropy was achieved simultaneously. For the FePt 4nm-SiO2 35 vol. % -C 20 vol. % films grown on top of the TiN-ZrO2 20 vol. % intermediate layer, well isolated FePt (001) granular films with coercivity higher than 18. 1 kOe and an average size as small as 6. 4 nm were achieved.

Advanced glycation end-products and methionine sulphoxide in skin collagen of patients with type 1 diabetes.

AIMS/HYPOTHESIS: We determined whether oxidative damage in collagen is increased in (1) patients with diabetes; (2) patients with diabetic complications; and (3) subjects from the Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) study, with comparison of subjects from the former standard vs intensive treatment groups 4 years after DCCT completion. SUBJECTS, MATERIALS AND METHODS: We quantified the early glycation product fructose-lysine, the two AGEs N (epsilon)-(carboxymethyl)lysine (CML) and pentosidine, and the oxidised amino acid methionine sulphoxide (MetSO) in skin collagen from 96 patients with type 1 diabetes (taken from three groups: DCCT/EDIC patients and clinic patients from South Carolina and Scotland) and from 78 healthy subjects. RESULTS: Fructose-lysine was increased in diabetic patients (p<0.0001), both with or without complications (p<0.0001). Controlling for HbA(1c), rates of accumulation of AGEs were higher in diabetic patients than control subjects, regardless of whether the former had complications (CML and pentosidine given as log(e)[pentosidine]) or not (CML only) (all p<0.0001). MetSO (log(e)[MetSO]) also accumulated more rapidly in diabetic patients with complications than in controls (p<0.0001), but rates were similar in patients without complications and controls. For all three products, rates of accumulation with age were significantly higher in diabetic patients with complications than in those without (all p<0.0001). At 4 years after the end of the DCCT, no differences were found between the previous DCCT management groups for fructose-lysine, AGEs or MetSO. CONCLUSIONS/INTERPRETATION: The findings suggest that in type 1 diabetic patients enhanced oxidative damage to collagen is associated with the presence of vascular complications.

Working memory deficits induced by single but not repeated exposures to domoic acid.

Single injections of domoic acid, given either intraperitoneally to mice or directly into the hippocampal formation of rats, have been shown to impair learning on the place version of the Morris water maze task and the eight arm radial maze task. The present study was designed to test whether both single and repeated exposures of intraperitoneally administered domoic acid (1.0 or 2.0 mg/kg) impair spatial working memory in mice on a delayed matching-to-sample task. DBA strain mice were given a series of four injections over a 7-day period consisting of either saline or one of two doses of domoic acid. During the 18 days of testing, each subject was given one trial per day consisting of one information run, followed by three test runs. On non-alternation days (days in which the correct response was the same as the preceding day) the saline injected group significantly outperformed the single injection 2.0 mg/kg domoic acid group. This indicates that domoic acid-treated animals were incapable of forming a memory that persisted for 24 h and hence were less able to utilize the prior day's experience. However, the repeated exposure groups did not perform as poorly on non-alternation days than the single exposure groups, indicating that domoic acid may affect multiple mechanisms involved in memory consolidation.

Repeated independent exposures to domoic acid do not enhance symptomatic toxicity in outbred or seizure-sensitive inbred mice.

Domoic acid (DA) is an environmental neurotoxin to humans. This work examines whether repeated exposure to subsymptomatic or symptomatic nonlethal doses of domoic acid leads to enhanced symptomatic toxicity in ICR outbred and DBA inbred strains of laboratory mice. A multiple independent exposure paradigm was designed in which doses were administered intraperitoneally every other day for 7 days to achieve four separate exposures to domoic acid. We first examined the effect of repeated exposure on serum clearance of domoic acid. Serum domoic acid levels did not differ following a single or repeated exposure. We next examined the effect of repeated exposure on symptomatic toxicity. The mean toxicity scores did not show a significant difference between single and repeated exposures of either subsymptomatic (0.5 mg/kg) or symptomatic sublethal (2.0 mg/kg) doses of domoic acid. We then examined the effects of repeated domoic acid exposure on a second strain of mouse. DBA mice were chosen based upon their sensitivity to kainic acid-induced seizures; however, the ICR mice were more sensitive to low-dose domoic acid toxicity, particularly in terms of onset and duration of stereotypic scratching behavior. Our results indicate that both strains of mice have comparable concentration-dependent toxic responses to domoic acid; however, differences exist in the magnitude of the response and in specific symptoms. The mean toxicity scores did not show a significant difference when a single exposure (1.0 and 2.0 mg/kg domoic acid) and repeated exposure of the same dose were compared in the DBA mice. This study provides no evidence that short-term repeated exposure to domoic acid in laboratory mice alters domoic acid clearance from the serum, or leads to a more sensitive or a greater neurotoxic response.

Domoic acid is a potent neurotoxin to neonatal rats.

Domoic acid induces a time-dependent neuroexcitotoxic effect in neonatal rats characterized by hyperactivity, stereotypic scratching, convulsions, and death with observable behaviors occurring at exposures 40 times lower by body weight in neonates than reported in adults. Low doses of domoic acid (0.1 mg/kg) induced c-fos in the central nervous system which was inhibited in part by 2-amino-5-phosphonovaleric acid, an NMDA receptor antagonist. Domoic acid caused no evidence of structural alteration in the brain of neonates as assessed by Nissel staining and cupric silver histochemistry. Domoic acid induced reproducible behavioral effects at doses as low as 0.05 mg/kg and induced seizures doses as low as 0.2 mg/kg. Determination of serum domoic acid levels after 60 min exposure indicated that serum levels of domoic acid in the neonates corresponded closely to the serum levels that induce similar symptoms in adult rats and mice. We conclude that neonatal rats are highly sensitive to the neuroexcitatory and lethal effects of domoic acid and that the increased sensitivity results from higher than expected serum levels of domoic acid. These findings are consistent with other findings that reduced serum clearance of domoic acid is a predisposing factor to domoic acid toxicity.

Brain Fos induction is a sensitive biomarker for the lowest observed neuroexcitatory effects of domoic acid.

Domoic acid induces Fos in several brain regions controlling memory processing and gastrointestinal functions. In the present study, we determined serum levels of domoic acid that caused observable effects, and examined whether brain c-fos was a sensitive marker for the lowest observed neuroexcitatory effects in mice. Five different doses (0.25 to 4.0 mg/kg) of domoic acid were intraperitoneally administered to mice, and the serum concentration of domoic acid was monitored using a radioreceptor assay. The earliest neuroexcitatory effect of domoic acid on behavior was observed in the form of hyperactivity which occurred at 0.5 mg/kg (0.076 +/- 0.02 microgram/ml serum domoic acid, means +/- SE, n = 5). However, stereotypic behavior (scratching) was observed only at doses > or = 1.0 mg/kg (0.25 +/- 0.02 microgram/ml). At 2.0 mg/kg (0.54 +/- 0.04 microgram/ml) and higher, convulsions and seizures occurred. Domoic acid induction of c-fos mRNA was detected in the whole brain at 1.0 mg/kg, whereas increased Fos immunostaining was localized in the dentate granule cells and the pyramidal cells of hippocampal formation at doses as low as 0.5 mg/kg (0.076 +/- 0.02 microgram/ml). Our results indicate that Fos expression in the hippocampus is a sensitive biomarker for the neuroexcitatory effects of domoic acid, being induced at doses of domoic acid lower than those that elicit stereotypic behavior.