Objective To explore the prognostic value of early lactate clearance rate in patients with respiratory failure.Methods 117 patients with respiratory failure and elevated blood lactate, admitted into respiratory intensive care unit( RICU) between January 2010 and December 2011, were retrospectively analyzed. Arterial lactate and arterial blood gas were measured before and 12h, 24h, 48h, and 72h after treatment. Then12h lactate clearance rate was calculated. The acute physiology and chronic health evaluation Ⅱ( APACHEⅡ) score was evaluated before and after 12h treatment. The mortality were compared between subgroups with different lactate normalization time( lt;24 h, 24 ～48 h, 48 ～72 h, and gt;72h, respectively) . The clinical data was compared between subgroups with different prognosis ( survival or non-survival ) and between subgroups with different lactate clearance rate( ≥10% as high lactate clearance rate, lt;10% as low lactate clearance rate) . Results The mortality of the patients with lactate normalization time in less 24 hours was significantly lower than that of the patients with lactate normalization time more than 72 hours ( 5. 3% vs. 89. 2% , P lt; 0. 001) . The 12 hour lactate clearance rate of the survival group was significantly higher than that of the non-survival group [ ( 43. 6 ±26. 8) % vs. ( 12. 3 ±39. 1) % , P lt;0. 01] . The mortality of the patients with high lactate clearance rate was significantly lower than that of the patients with lowlactate clearance rate( 25. 8% vs. 71. 4% , P lt;0. 01) . Conclusion Early lactate clearance rate can be used as a marker for prognosis of patients with respiratory failure.
Objective To establish an animal model for repairing the sciatic nerve defect with a biodegradable poly D,L-lactic acid/nerve growth factor (PDLLA/NGF) that can control the release conduit in rats and to observe an effect of the conduit on the sciatic nerve regeneration. Methods The PDLLA conduit and the PDLLA/NGF-controlled release conduit (NGF 450 U per conduit) were madewith the solvent-volatilixation method. Forty male SD rats were randomly and equally divided into 4 groups. The middle segments (10 mm) of the sciatic nerves of the rats were excised and were then repaired with the sciatic nerve autograft(Group A), with the PDLLA conduit (Group B), with the PDLLA conduit and an injection of NGF (30 U) into the conduit (Group C), and with the PDLLA/NGF controlled-release conduit (Group D), respectively, with the 10-mm nerve defect left behind. Three months after operation, the morphologic parameters of the nerve regeneration were observed and evaluated under light microscope and electron microscope, and the image analysis was also made. Results Three months after operation, porous adherence between the conduit and the surrounding tissues could be observed. The conduit presented a partial biodegradation but still remainedintact in the outline and the proximal nerve regenerated through the conduit cavity. Based on the histological observation, the quantity, uniformity, and maturity of the nerve fiber regeneration in Groups A and D were better than those in Groups B and C. The image analysis indicated that there were no significant differences in the nerve fiber diameter, axon diameter or myelin thickness between Group A and Group D (P＞0.05). However, all the parameters in Groups A and D were better than those in Groups B and C (P＜0.05). Conclusion The PDLLA/NGF-controlled release conduit can effectively promote the sciatic nerve regeneration of rats. Its morphological index is similar to that of the nerve autograft.
Objective To investigate the feasibility oftissue engineered intervertebral disc for regeneration of discs. Methods A three-dimensional porous poly(L-lactic-co-glycolic acid) (PLGA) scaffold was fabricated by temperature induced phase separation method. Human fetal disc cells were isolated and cultured in vitro. The disc cells labeledwith a PKH-26 fluorescent dye were seeded into a threedimensional porous scaffold. The proliferation of disc cells with PKH-26 fluorescent labels was assessed by using MTT uptake, laser fluorescence microscopy and SEM. Results Human fetal disc cells displayed a polygonal shape in primary monolayer culture. A regular arrangement and microtubules orientationstructure scaffold with 50-300 μm in diameter was fabricated by thermal-induced phase separation technique. MTT uptake and fluorescent microscopy examination indicated that the seeded disc cells were viable and showed proliferation activity within a porous scaffold. Conclusion The above findings support potential applications of tissue engineered disc in treatment of disc degenerative diseases.
Objective To study the influence of in vitro force-vascularization on in vivo vascularization of porous polylactic glycolic acid copolymer(PLGA) scaffolds with internal network channels (PPSINC). Methods After the in vitro forcevascula ization of PPSINCs covered with microvessel endothelial cells (MVEC) of mice, they were divided into two groups: the force-vascularization group (group A) and the control group with only PSINCs (group B). All the PPSINCs were planted in the mesentery of 12 mice for 2 and 4 weeks, the PPSINCs were cut out, the vascular ization of PPSINCs was investigated by histology and immunohistochemistry, and the vascularization area of the histologic section of the PPSINCswas measured with the computer-assistant image analysis system. Result After the in vitro forcevascularization of PPSINCs, the MVEC of the mice sticking on the channel wall could be seen. After the scaffold was im planted into the mice for 2 weeks, the vascularization area of the histologic section of PPSINCs (VA) in group A (2 260.91±242.35 μm2) was compared with that in group B (823.64±81.29 μm2)，and the difference was sig nificant in statistics（P＜0.01).The VA for 4 weeks in group A (17 284.36 ±72.67 μm2) was compared with that in group B (17 041.14±81.51 μm2), and the difference was not significant in statistics（P＞0.05）.The area of the actin positivestaining (AA) in the histologi c section of PPSINCs for 2 weeks’ implantation in group A (565.22±60.58 μm2) was compared with that in group B (205.91±16.25 μm2), and the difference was signi ficant in statistics（P＜0.01). After the implantation for 4 weeks, the VA in group A (4 321.09±19.82 μm2) was compared with group B (4 260.28±27.17 μm2), and the difference was not significant in statistics（P＞0.05）. Conclusion The PPSINC is a good simple scaffold model of vasculariazation. The in vitro force-vascularization can increase the in vivo vascularization of PPSINCs in the early stage.
The poly-lactic acid membrane is characterized by its non-toxicity, non-carcinogenic and the property of degradation in the body in animal experiment, this membrane was wrapped around the tenorrhaphy site. The results showed that 3 to 9 weeks after operation there was an intact space surrounding the tendon, and the membrane began to degradate at 24 weeks, might achieve the purpose to prevent the formation of adhesion. From Nov. 1985 to Sept. 1989, this membrane was applied to 20 tendons of 14 patients. The follow-up results showed that the satisfactory rate was 81.8% .the indications of using poly-lacic acid membrane were primary, delayed primary and secondary suture of flexor tendon injuries in areas of the fingers.
Objective To prepare a self-made compound, hemostatic jelly with polylactic acid(PLA), which has the hemostatic and absorbable effect on injured cancellous bone. Methods Two bone defects of 5 mm in diameter and 4 mm in depth were subjected on 20 health rabbits by drilling through their either outside plate of the iliac, and were filled with hemostatic jelly(group A), bone wax(group B) and blank(group C) respectively. Hemostasis were observed and recorded after 1 and 10 minutes. Five specimens were harvested at 2, 4, 8 and 12 weeks postoperatively for histological observation. Results ① Hemostatic effect: Bleeding of injured spongy bone stopped within 10 minutes after the treatment of hemostatic jelly and bone wax, but bleeding of balnk did not stop. Hemostatic jelly and bone wax adhered to bone defects firmly within 10 minutes was after the treatment. ② Absorbable effect: Hemostatic jelly and bone defects have not changed visibly in the first 2 weeks. With histological observation 4 to 8 weeks after the operation, hemastatic jelly was absorbed gradually and replaced by osteogenous tissue. It was absorbed completely after 8 to 12 weeks. Bone wax was not absorbed after 12 weeks, no new bone tissue was observed at bone wax area. The blank was replaced by connective tissue and osteogenous tissue partially after 12 weeks. Conclusion The compound hemostatic jelly manifests both hemostatic and absorbable effects on injured cancellous bone and may substitute for bone wax in clinical application.
Objective To study the result of using nerve conduit coated with chitin and filled with a guide-fiber to repair peripheral nerve defect. Methods Twenty-four female adult SD rats were made the model of 14 mm-gap on bilateral sciatic nerve under sterile condition. The rats were randomly divided into 4 groups(n=6),group A: polymer polyglycolic-lactic acid(PGLA) nerve conduit coated with chitin and filled with a guide-fiber as experimental group to repair 14 mm gap of rat sciatic nerve；group B: PGLA nerve conduit coated with chitin； group C: PGLA nerve conduit； group D: autograft (control group). The repair result was evaluated by normal observation, EMG testing and S-100 histological immunostaining analysis 4 and 12 weeks after operation.Results Four weeks after the operation，there were new regenerated immature fibers in groups A,B and C, 12 weeks after the operation, the regenerated nerve fibers were seen to have bridged the gap. There were myelinated fibers equably distributed and rarely newgenerated nerve fibers in distal parts of group D. The repair result of PGLA nerve conduit coated with a chitin and filled with guide-fiber was better than that of groups B and C（Plt;0.05）. There was significant difference of nerve fiber diameter，thickness of myelin sheath and fiber density in group D from those in groups A, B and C（Plt;0.05），but there were degenerative changes such as vacuoles insheaths and myelin separation in proximal and few new regenerated nerve fibers in distal parts of group D. Conclusion PGLA nerve conduit coated with chitin and filled with a guide-fiber offers a possible substitute for the repair of peripheral nerve defect.
Objective To explore the predictive value of simplified acute physiological score Ⅱ (SAPS-Ⅱ) combined with lactate clearance rates (LCR) at different moments for mortality in sepsis patients. Methods A total of 188 patients with sepsis admitted in the hospital from April 2020 to February 2023 were selected, who were evaluated using the SAPS-Ⅱ scale. Spectrophotometry was used to detect blood lactate at baseline, after 6h, 12h, 24h, and 48h, then the LCR after 6h, 12h, 24h, and 48h were calculated. The patients were divided into a survival group (n=139) and a death group (n=37) based on 28 day outcome. Logistic regression analysis was used to explore the risk factors of sepsis death, and the efficacy of SAPS-Ⅱ scores combined with LCR at different moments in predicting patient death was analyzed using receiver operating characteristic (ROC) curve. Results Twelve patients fell off, and 37 died in the remaining 176 patients, the mortality rate was 21.02%. The age, temperature, random blood glucose, blood urea nitrogen, serum creatinine, and SAPS- Ⅱ scores in the death group were significantly higher than those in the survival group (P<0.05), while platelet count and LCR at all moments were significantly lower than those in the survival group (P<0.05). The LCR of the death group continued to decrease with time. The trend of changes in the survival group were opposite, and the differences in the two groups between each two moments were statistically significant (P<0.05). The SAPS-Ⅱ scores and LCR at all moments were risk factors for patient death (P<0.05). The SAPS-Ⅱ score and LCR at all moments had predictive value for patient death, and the area under ROC curve of the combined prediction was 0.921 (95%CI 0.825 - 1.000), which was higher than the individual prediction and LCR at each moment combined with SAPS II score prediction (P<0.05). Conclusion The SAPS-Ⅱ scores and LCR at different moments are all related to death of sepsis patients, and the combined prediction of death by the above indicators is highly effective.
Objective To determine the incidence of vitamin B1 deficiency in critically ill patients, to compare vitamin B1 levels between septic and non-septic patients, and to explore the relationship between vitamin B1 levels and lactate levels. Methods Using a retrospective study method, critically ill patients admitted to the Department of Intensive Care of Nanjing Drum Tower Hospital from February 2022 to November 2022 were included in the study, and the patients were divided into sepsis and non-sepsis groups according to the admission diagnosis, and the differences in the vitamin B1 levels of the patients between the two groups were analyzed, as well as the correlation between the vitamin B1 levels and the lactic acid levels. Results There was a significant difference in serum vitamin B1 levels between the sepsis patients and the non-sepsis patients [(1.6±0.3)ng/mL vs. (2.1±0.2)ng/mL, P=0. 009]. For all patients, there was no correlation between vitamin B1 levels and lactate levels. But when the patient was in a hyperlactate state (lactate level ≥2 mmol/L), vitamin B1 levels were significantly negatively correlated with lactate levels (r=–0. 229, P=0. 004). Conclusions Vitamin B1 deficiency is prevalent in critically ill patients and is strongly correlated with whether or not the patient is septic. Vitamin B1 levels are significantly and negatively correlated with lactate levels when the patient's lactate level is ≥2 mmol/L.
Objective To investigate if lactic acid can promote the expression of vascular endothelial growth factor (VEGF) in the rat retinal explants.Methods The retinas of two-week neonatal SD rats were placed onto the culture plate inserts and incubated with Dulbeccoprime;s modified Eagleprime;s medium （DMEM） plus 2% fetal bovine serum (FBS) containing 10,20,30 mmol/L of lactic acid, respectively. Each group had 24 retinas. At 24 hours after incubation, the retinas were sectioned for light microscopy and the expression of VEGF was measured by real time PCR and Western blot. Results The cultured retinas maintained intact construction, and no cytolysis and apoptosis were observed under light microscope. RT-PCR showed the levels of VEGF mRNA were 0.74plusmn;0.06 for 10 mmol/L lactic acid group, 0.99plusmn;0.12 for 20 mmol/L group, and 1.45plusmn;0.17 for 30 mmol/L group respectively. VEGF expression was 0.34plusmn;0.15 for 10 mmol/L, 0.54plusmn;0.16 for 20 mmol/L, and 0.93plusmn;0.23 for 30 mmol/L group respectively by Western blot. Both PCR and Western blot showed 30 mmol/L of lactic acid significantly increased the levels of VEGF mRNA and VEGF expression. Conclusion The induction of retinal VEGF by lactic acid is concentration-dependent.