Visualization of therapeutic intervention for acute liver injury using low-intensity pulsed ultrasound-responsive phase variant nanoparticles.

Acute liver injury (ALI) is a highly fatal condition characterized by sudden massive necrosis of liver cells, inflammation, and impaired coagulation function. Currently, the primary clinical approach for managing ALI involves symptom management based on the underlying causes. The association between excessive reactive oxygen species originating from macrophages and acute liver injury is noteworthy. Therefore, we designed a novel nanoscale phase variant contrast agent, denoted as PFP@CeO2@Lips, which effectively scavenges reactive oxygen species, and enables visualization through low intensity pulsed ultrasound activation. The efficacy of the nanoparticles in scavenging excess reactive oxygen species from RAW264.7 and protective AML12 cells has been demonstrated through in vitro and in vivo experiments. Additionally, these nanoparticles have shown a protective effect against LPS/D-GalN attack in C57BL/6J mice. Furthermore, when exposed to LIPUS irritation, the nanoparticles undergo liquid-gas phase transition and enable ultrasound imaging.

Recent Advance in Source, Property, Differentiation, and Applications of Infrapatellar Fat Pad Adipose-Derived Stem Cells.

Infrapatellar fat pad (IPFP) can be easily obtained during knee surgery, which avoids the damage to patients for obtaining IPFP. Infrapatellar fat pad adipose-derived stem cells (IPFP-ASCs) are also called infrapatellar fat pad mesenchymal stem cells (IPFP-MSCs) because the morphology of IPFP-ASCs is similar to that of bone marrow mesenchymal stem cells (BM-MSCs). IPFP-ASCs are attracting more and more attention due to their characteristics suitable to regenerative medicine such as strong proliferation and differentiation, anti-inflammation, antiaging, secreting cytokines, multipotential capacity, and 3D culture. IPFP-ASCs can repair articular cartilage and relieve the pain caused by osteoarthritis, so most of IPFP-related review articles focus on osteoarthritis. This article reviews the anatomy and function of IPFP, as well as the discovery, amplification, multipotential capacity, and application of IPFP-ASCs in order to explain why IPFP-ASC is a superior stem cell source in regenerative medicine.

Determination of benzalkonium chloride in viscous ophthalmic drops of azithromycin by high-performance liquid chromatography.

A high-performance liquid chromatography (HPLC) system was used in the reversed phase mode for the determination of benzalkonium chloride (BKC) in azithromycin viscous ophthalmic drops. A Venusil-XBP(L)-C(18) (150 mmx4.6 mm, 5 microm) column was used at 50 degrees C. The mobile phase consisted of a mixture of methanol-potassium phosphate (16:5, v/v). Two sample preparation methods were compared. The results suggested that, compared with an extraction procedure, a deproteinization procedure was much quicker and more convenient. Using the deproteinization procedure for sample preparation, calibration curves were linear in the range 5.0 to approximately 50 microg/ml. The within-day and inter-day coefficients of variation were less than 10%. The average recoveries were determined as 96.70%, 98.52%, and 97.96% at concentrations of 10.0, 30.0, and 50.0 microg/ml, respectively. Variability in precision did not exceed 5%. In conclusion, this HPLC method using a simple sample treatment procedure appears suitable for monitoring BKC content in azithromycin viscous ophthalmic drops.

[A study on expression of caspase-8 in organs of rats after electrical injury at antemortem or postmortem].

OBJECTIVE: This study was conducted to detect the expression of caspase-8 in organs of rats after The electrical injury so as to elucidate whether caspase-8 is useful in identifying electrical lesion. METHODS: experiment included two parts. In the first part (the antemortem electrical injury part), thirty-five healthy male SD rats were randomly divided into seven groups (n = 5 per group), i. e. the group of rats subjected to instantaneous electrothanasia; the groups of rats subjected to cervical dislocation at 1 h, 2 h, 4 h, 8 h after electrical injury; the sham group and the normal control group. In the second part (the postmortem electrical injury part), twenty-five healthy male SD rats wererandomly divided into five groups (n=5 per group), i. e. the groups of rats electrically injured just after death, and at 15 min, 30 min, 60 min after death; and the postmortem sham group. All experimental rats were given respectively an electric shock with two metal clamps that were connected with two poles of 220 V alternating current by clamping the rats' left hind limbs and right forelimbs. The rats of sham group after death were clamped but not electrified. The brain, lung, heart, liver, spleen, kidney, the muscle of electrified limb, the cutis of electrified limb of all experimental rats and those organs of control groups were dissected to detect the expression of caspase-8 by immunohistochemistry staining, and the staining intensities were assessed by image analysis system. RESULTS: In the antemortem electrical injury groups, the expression of caspase-8 was positive in brain, heart, liver and kidney; the strongest staining intensity appeard at 4 h after electrical injury and decreased at 8 h after electrical injury. In the group of rats electrically injuryed just after death, the expression of caspase-8 was faint, and the expression of caspase-8 in spleen, lung, muscle and cutis was negative in the other groups. The expression of caspase-8 in all detected organs was negative in the other rats that were electrified after death. CONCLUSION: Caspase-8 can be regarded as an index in identifying electrical injury and distinguishing between antemortem and postmortem electrical injuryies.

[Expression of c-Fos in rats organs after electrical injury].

OBJECTIVE: To study the expression of c-fos in organs after rats electrified. METHODS: The brain, lung, heart, liver, spleen, kidney, muscle of electrified limb, and cutis of electrified limb of all experimental rats and those organs of control groups were dissected to detect the expression of c-fos by using immunohistochemistry staining, and the staining intensity were assessed by image analysis system. RESULTS: The expression of c-fos was observed in brain, heart, liver, lung, kidney and muscle in electrified directly group, the amount of expression reached peak at 2 h after electrified and decreasing at 8 h after electrified, and the expression showed faintness in electrified at the immediate after death group. The expressions of c-fos in spleen and cutis is negative in all groups. The expression of c-fos in all detected organs was negative in other rats that were electrified after death. CONCLUSION: c-fos can be regard as a target in identifying electrical injury, whether it formed at antemortem or postmortem.

[Expression of PDGF-B after fluid percussion brain injury in rats].

OBJECTIVE: To elucidate the changes of PDGF-B chain in the brain injured by fluid percussion. METHODS: The expression of PDGF-B protein was studied by immunohistochemistry and the results were assessed by image analysis system. RESULTS: Enhanced expression of PDGF-B protein induced by fluid percussion injury was seen at 1 h, and its marked up-regulation was noted at 4-7 days, and then the expression became decreased but it remained above the control levels till 14 days after injury. CONCLUSION: Fluid percussion brain injury induced expression of PDGF-B. The regular change pattern of PDGF-B level in time course seems to be of value in estimating the age of brain injury.

[Co-expressions of phosphoenolpyruvate synthetase A (ppsA) and transketolase A (tktA) genes of Escherichia coli].

Metabolic engineering is the analysis of metabolic pathway and designing rational genetic modification to optimize cellular properties by using principle of molecular biology. Aromatic metabolites such as tryptophan, phenylalanine, and tyrosine are essential amino acids for human and animals. In addition, phenylalanine is used in aspartame production. Escherichia coli and many other microoganism synthesize aromatic amino acids through the condensation reaction between phospho-enolpyruvate (PEP) and erythrose-4-phosphate(E4P) to form 3-deoxy-D-arabinoheptulosonate 7-phosphate(DAHP). But many enzymes compete for intracellular PEP, especially the phosphotransferase system which is responsible for glucose transport in E. coli. This system uses PEP as a phosphate donor and converts it to pyruvate, which is less likely to recycle back to PEP. To channel more carbon flux into the aromatic pathway, one has to overcome pathways competing for PEP. ppsA and tktA are the key genes in central metabolism of aromatic amino acids biosynthesis. ppsA encoding phosphoenolpyrucate synthetase A (PpsA) which catalyzes pyruvate into PEP; tktA encoding transketolase A which plays a major role in erythrose-4-phosphate (E4P) production of pentose pathway. We amplified ppsA and tktA from E. coli K-12 by PCR and constructed recombinant plasmids of them in pBV220 vector containing P(R)P(L) promoter. Because of each gene carrying P(L) promoter, four productions of ligation were obtained. The monoclonal host containing recombinant plasmids was routinely grown in Luria-Bertani (LB) medium added Ampicillin at 37 degrees C overnight, and then inoculated in LB (Apr) medium by 3%-5% in flasks on a rotary shaker at 30 degres C, induced at 42 degrees C for 4.5 hours when OD600 = 0.4, cells were obtained by centrifugation at 10,000 r/min at 4 degrees C. The results of SDS-PAGE demonstrated that the bands at 84kD and 73kD were more intensive than the same ones of the controls. The specific activity of PpsA in crude extracts was increased by 10.8-fold, and TktA, by 3.9-fold. When both genes were co-expressed in E. coli, the activity of PpsA varied from 2.1-9.1 fold comparing to control, but the activity of TktA was relatively stable(3.9-4.5 fold). Whatever the two genes were expressed respectively or cooperatively, both could promote the production of DAHP, the first intermediate of the common aromatic pathway, but co-expression was more effective on forming DAHP. The results demonstrate that co-expression of ppsA and tktA can improve the production of DAHP to near theoretical yield. This report details a different strategy based on co-expression of two genes in one vector in vivo to release the burden and paves the way for construction of genetic engineering bacteria for further research.