[Clinical Characteristics and Risk Factors in Children with Acute Leukemia Complicated with Multiple Drug Resistant Bacterial Septicemia].

OBJECTIVE: To investigate the clinical characteristics and risk factors of acute leukemia complicated with multi-drug resistant bacterial septicemia in children. METHODS: The clinical data of children with acute leukemia complicated with septicemia admitted to the Affiliated Hospital of Guangdong Medical University from January 2013 to May 2021 were retrospectively analyzed. Their flora composition and drug resistance were also analyzed. The children were divided into multi-drug resistant bacteria (MDRB) group and non-multi-drug resistant bacteria (non-MDRB) group according to the drug sensitivity results, and the differences in clinical data between the two group were compared. RESULTS: A total of 108 children had drug sensitivity results, 47 cases in the MDRB group, including 26 strians of Gram-positive bacteria (G+), the most common multi-drug resistant G+ bacteria were coagulase-negative staphylococci (CoNS) and Staphylococcus aureus, and the most common multi-drug resistant Gram-negative bacteria G- bacteria were Escherichia coli and Klebsiella pneumoniae subspecies pneumoniae. Compared with non-MDRB group, children in MDRB group had higher C-reactive protein (CRP) level and mortality rate (P <0.001, P =0.009), lower initial empirical anti-infection efficiency (P <0.001), and were more likely to have septic shock (P =0.003). Logistic analysis showed that the risk factors of acute leukemia complicated with MDRB septicemia in children were previous MDRB infection (OR =6.763, 95% CI: 1.141-40.092, P =0.035), duration of agranulocytosis before infection≥7 days (OR =3.071, 95% CI: 1.139-8.282, P =0.027), and previous use of antimicrobial drugs within 90 days before infection (OR =7.675, 95% CI: 1.581-37.261, P =0.011). CONCLUSIONS: The clinical features of acute leukemia complicated with MDRB septicemia in children include a heavy inflammatory response, significantly elevated CRP, susceptibility to secondary septic shock, low efficiency of initial empirical anti-infective therapy, and high mortality rate. Previous MDRB infection, duration of agranulocytosis before infection≥7 days, and previous use of antimicrobial drugs within 90 days before infection are risk factors of acute leukemia complicated with MDRB septicemia in children.

[Toxic Effects of Long-term Exposure to PM2.5 and Protective Effects of Chitosan on Bone Marrow Hematopoietic Environment of the Mice].

OBJECTIVE: To investigate the toxic damage and possible mechanism of chronic exposure of ambient particulate matter (PM2.5) to the marrow micro-environment of the mice, and the protective effect of chitooligosaccharides. METHODS: Mice were treated with different doses (150, 300, 600 mg/kg) of chitosan after exposure to PM2.5, and then the mice were divided into: high dose group, medium dose group, low dose group according to the given dose, and the model group and the drug group were set as well. The productions of inflammatory cytokines IL-2, IL-8, TPO and VCAM-1 in marrow tissues were detected by ELISA, the expression of CXCL12 and CXCR4 protein in bone marrow tissues were measured by Western blot. RESULTS: Compared with the mice in control group, IL-2 secretion and CXCL12 expression were decreased in the bone marrow of PM2.5 infected mice, while the secretion of IL-8, TPO and VCAM-1 were significantly increased, and CXCR4 expression was significantly up-regulated (P<0.05). Compared with the mice in control group, drug group and other dose groups, IL-2 secretion in the bone marrow of the mice in high-dose group was significantly increased, and IL-8, TPO and VCAM-1 secretion were significantly decreased (P<0.05). CONCLUSION: Chronic exposure of PM2.5 shows some toxicity effect on marrow micro-environment. Chitosan oligosaccharide can reduce the pathologic damage of bone marrow and the toxicity to bone marrow microenvironment caused by PM2.5 at a certain extent.

[The Comparison of Iron Deficiency Anemia Rat Treated with Hydroxypropyl Chitosan Ferrous Ion Complex and Ferrous Sulfate].

OBJECTIVE: To observe and compare the therapeutic effects of hydroxypropyl chitosan ferrous ion complex solution and ferrous sulfate solution in iron deficiency anemia rats and their effects on gastric mucosa. METHODS: Seven rats were randomly selected from thirty five SPF grade SD rats as control group, and were fed with normal diet, distilled water (E). The rest of SD rats were fed with low iron feed and distilled water plus continuous tail vein bloodletting to establish the iron deficiency anemia model. After the model was established successfully, the rats were randomly divided into four groups: blank control group (A), iron deficiency anemia control group (B), ferrous sulfate group (C), hydroxypropyl chitosan ferrous ion complex (HPCTS-Fe2+) group (D). Group A was killed and the gastric tissue was taken to make the pathological section. Group E was fed with normal feed and distilled water continually. Group B, C and D were fed with low iron feed and distilled water. Moreover, Group C and group D were treated with ferrous sulfate solution and HPCTS-Fe2+ solution respectively to made the blood recover treatment (4 mg / kg of iron each time, twice a day). During the treatment period, Ret%, SF and blood routine were checked regularly. After 6 weeks of treatment, the rats were killed, and the gastric tissue was taken to make the pathological section, and the condition of gastric mucosa was observed by the light microscope. RESULTS: After modeling, except the normal control group, the hair color of the rats in the four groups showed dark yellow and the belly of the toes became white gradually. HGB, HCT, Ret%, MCV, MCH, MCHC and SF decreased significantly (P < 0.05). After treatment, the rats with dark yellow hair in group C and D were improved, and the toe abdomen turned pink gradually. RBC, HGB, HCT, Ret%, MCV, MCH, MCHC and SF in rats in group C and D increased, which were higher than those in group B (P < 0.05). The HGB of the rats in group D was higher than that of group C in day 28th during treatment and the Ret% was higher than that in group C at day 10th (P<0.05).After treatment, the liver and spleen of the rats in group C and D were lighter than those in group B (P<0.05).The gastric mucosa in group A, B, D and E was not damaged obviously, while it was slightly irritated and damaged in group C. CONCLUSION: Hydroxypropyl chitosan ferrous complex solution can improve the hemoglobin level of SD rats with iron deficiency anemia, which is stronger than ferrous sulfate solution and shows no damage to gastric mucosa.