[Research advances on thymosin β4 in promoting wound healing]

With the aging of population and the development of social economy, the incidence of chronic wounds is increasing day by day, while the incidence of burns and trauma remains at a high level, making wound repair an increasingly concerned area in clinical practice. Thymosin β4 is a naturally occurring small molecule protein in vivo, which is widely distributed in a variety of body fluids and cells, especially in platelets. Thymosin β4 has biological activities of promoting angiogenesis, anti-inflammation, anti-apoptosis, and anti-fibrosis, and has many important functions in wound repair. Thymosin β4 has been observed to promote the healing of various wounds, such as burns, diabetic ulcers, pressure ulcers. This paper will review the molecular structure, mechanism of wound healing promotion, pharmacokinetics, and clinical application of thymosin β4, aiming to introduce its potential in wound treatment and the shortcomings of current researches.

[Influencing factors of postoperative acute kidney injury in patients undergoing cardiac surgery]

Objective: To analyze the influencing factors of acute kidney injury (AKI) in patients after cardiac surgery using levosimendan or dobutamine, and explore the effect of positive inotropic drugs on AKI. Methods: The clinical data of 417 patients undergoing cardiac surgery from January to June 2018 in Beijing Anzhen Hospital and treated with levosimendan or dobutamine during perioperative period were retrospectively reviewed and collected. Patients were divided into AKI group and non-AKI group according to whether AKI occurred. Univariate logistic regression analysis was used to analyze the factors related to the occurrence of AKI. The statistically significant factors (P<0.05) were further included in the multivariate logistic regression analysis. Results: Totally, 417 patients were enrolled in the study, with a mean age of (58.2±10.4) years old and a male rate of 65.0% (n=271), and the AKI incidence rate was 25.2% (105/417). Univariate logistic regression analysis showed that male, chronic kidney disease, high serum creatinine level in preoperative period, aortic obstruction time ≥ 120 minutes and extracorporeal circulation time ≥ 120 minutes were risk factors for AKI (all P<0.05). Vasodilator and levosimendan treatment during perioperative period were protective factors (P<0.05). Multivariate logistic regression analysis showed that chronic kidney disease (OR=17.291, 95%CI: 4.335-68.960, P<0.001) and high serum creatinine level (OR=1.097, 95%CI: 1.074-1.121, P<0.001) in preoperative period were independent risk factors for AKI. Perioperative application of levosimendan (OR=0.533, 95%CI: 0.288-0.984, P=0.044) was an independent protective factor. Conclusions: Risk factors for AKI after cardiac surgery include chronic kidney disease and high serum creatinine level in preoperative period. The use of levosimendan during preoperative period has the potential effect to protect against AKI.

[IgG4 immunohistochemistry in Riedle thyroiditis]

Objective: To observe the histopathological changes and immunohistochemical expression of IgG4 in Riedle thyroiditis (RT) and to study the relationship between RT and IgG4-related diseases (IgG4-RD). Methods: A total of 5 RT patients were collected from the Department of Pathology, Peking Union Medical College Hospital during April 2012 to August 2014. The clinical and immunohistochemical features were analyzed in the 5 patients. Histopathologic analysis was performed on hematoxylin and eosin-stained sections. Results: There were one male and four female patients, aged 52 to 78 years (median 59 years). Five cases were characterized by multiple nodules of thyroid, which increased year by year. All patients were found to have surrounding tissue compression symptoms and signs. Two female patients were found to have hypothyroidism. The serum concentration of IgG was elevated in 2 cases, and the serum concentration of IgG was not tested before operation in the remaining patients. By ultrasound, all presented as low echo or medium low echo. Strong echo occasionally appeared in hypoechoic nodules. Microscopically, fibrous tissue hyperplasia was infiltrated with varying numbers of lymphocytes and plasma cells. The occlusion of phlebitis was found in 4 cases and eosinophils were found in 3 cases. IgG4 counts and IgG4/IgG ratios in 5 cases were 20/HPF, 16%; 60/HPF, 82%; 22/HPF, 28%; 400/HPF, 266% and 33/HPF, 71%, respectively. Conclusions: With the similar pathological manifestations between RT and IgG4-RD, immunohistochemical staining shows that the number of IgG4 positive plasma cells and IgG4/IgG ratio of RT are increased in varying degrees. Some cases meet the diagnostic criteria of IgG4-RD, and speculate that some cases of RT belong to IgG4-RD.

Role of selenoprotein S (SEPS1) -105G>A polymorphisms and PI3K/Akt signaling pathway in Kashin-Beck disease

OBJECTIVE

To investigate the relationship between SEPS1 polymorphism and phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway in Kashin-Beck disease (KBD) and further explore the pathogenesis of KBD.

METHODS

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to detect SEPS1 -105G>A polymorphism in 232 cases and 331 controls. The protein expressions of PI3K/Akt signaling molecules in whole blood and chondrocytes were detected by Western blot.

RESULTS

The frequencies of SEPS1 -105G>A genotype AA (21.1% vs 3.0%) and minor allele A (34.1% vs 16.0%) in KBD are significantly higher than those in controls (OR: 8.020, 95% confidence interval (95% CI) 6.341-10.290, P < 0.0001; OR: 2.470, 95% CI 2.001-4.463, P < 0.0001, respectively). SEPS1 AA genotype was an independent risk factor for KBD (adjusted OR: 9.345, 95% CI 4.254-20.529; P < 0.0001). The expression of Gβγ, PI3Kp110, pAkt and pGSK3β in KBD group were higher than that in control group (all P < 0.05). Gβγ, pAkt and pGSK3β protein expression of AA and GA increased than GG (all P < 0.05). Cell apoptosis was increasing and molecule expression of PI3K/Akt signaling pathway were up-regulated in the tert-Butyl hydroperoxide (tBHP)-injured group, the cell apoptosis and expression levels of PI3K/Akt in Na2SeO3 group were decreased.

CONCLUSIONS

The SEPS1 -105G>A is associated with an increased risk of KBD and influences the expression of PI3K/Akt signaling pathway in KBD patients. Apoptosis induced by tBHP in chondrocyte might be mediated via up-regulation of PI3K/Akt, Na2SeO3 has an effect of anti-apoptosis by down-regulating of PI3K/Akt signaling pathway.

Effect and mechanism of andrographolide on the recovery of Pseudomonas aeruginosa susceptibility to several antibiotics

Effectiveness and mechanism of action of andrographolide on the recovery of Pseudomonas aeruginosa susceptibility to antibiotics was investigated. In the presence of andrographolide, the Mueller-Hinton broth dilution method measured minimal inhibitory concentrations (MIC) of ceftazidine, cefpirome, chloramphenicol, L-ofloxacin, kanamycin, imipenem and meropenem. Real-time fluorescence quantitative polymerase chain reaction was used to determine mexB mRNA expressions in P. aeruginosa PAO1 strain and MexAB-OprM overexpressing strain. Relative mexB mRNA expression was detected in both strains incubated for 3 and 9 h. When andrographolide-treated groups were compared with controls, the MIC of ceftazidine, cefpirome, L-ofloxacin and meropenem for both strains decreased, and the relative mexB mRNA expression was significantly lower, although between andrographolide groups there were no significant differences. Compared with the inactivated quorum-sensing system, relative amounts of mexB mRNA in the PAO1 strain and MexAB-OprM overexpressing strain in the activated quorum-sensing system increased 10- and 30-fold, respectively. Andrographolide recovered P. aeruginosa susceptibility to antibiotics and reduced the MexAB-OprM efflux pump expression level.

[Intrathecal injection of NOS antisense oligonucleotides inhibits the increase of NMDA1AR mRNA expression in the spinal cord and brainstem of morphine-withdrawal rats]

Methods of reverse transcription polymerase chain reaction (RT-PCR), intrathecal injection and antisense drugs were used to study the effects of nitric oxide (NO) on the scores of morphine-withdrawal syndrome and the expression of NMDA1AR mRNA in rat spinal cord and brainstem. Intrathecal injection of NOS antisense oligonucleotides (AS-ONs) significantly decreased the scores of morphine-withdrawal symptoms. The effect of nNOS AS-ONs was greater than that of eNOS AS-ONs. The expression of NMDA1AR mRNA in the spinal cord and brainstem increased in morphine-dependent rats and increased to a greater extent in morphine-withdrawal rats. Intrathecal injection of nNOS AS-ONs significantly inhibited the increased expression of NMDA1AR mRNA in the spinal cord and brainstem of morphine-withdrawal rats. Intrathecal injection of eNOS antisense oligonucleotides inhibited the expression of NMDA1AR mRNA in the spinal cord of morphine-withdrawal rats, but did not in the brainstem. It is suggested that NO mediates morphine-withdrawal reaction and participates in modulating the expression of NMDA1AR mRNA in morphine-withdrawal rats.

[NO involvement in mediation of spinal neuron sensitization in morphine-withdrawal rats]

The effects of nitric oxide (NO) on the activation of spinal cord neurons were studied using immunocytochemistry, intrathecal injection and antisense oligonucleotides (AS-ONs) techniques in morphine-withdrawal rats. Acute administration of naloxone and chronic administration of morphine changed neither the expression of Fos-LI and NADPH-d positive neurons nor the expression of Fos/NADPH-d double-labeled neurons in the spinal cord of rats. Fos-LI, NADPH-d positive and Fos/NADPH-d double-labeled neurons were increased significantly in number in morphine-withdrawal rats and they were observed in all the laminae of the spinal cord. Intrathecal injection of L-NA, nNOS antisense oligonucleotides significantly inhibited the expression of Fos-LI in the spinal cord and decreased the scores for morphine-withdrawal symptoms in morphine-withdrawal rats, but not in nNOS-S group. The results suggest that NO mediates the spinal neurons sensitization in morphine-withdrawal rats.

[Increased expression of formalin-induced Fos and NADPH-d positive neurons in the spinal cord of morphine-tolerant rats]

Fos immunocytochemistry, NADPH-d histochemistry and Fos/NADPH-d double-labeling method were used to study the changes in formalin-induced Fos, NADPH-d positive and Fos/NADPH-d double-labeled neurons in the spinal cord of morphine-tolerant rats. Formalin-induced Fos-like immunoreactivity (Fos-LI) was located in the superficial laminae and neck of ipsilateral spinal cord. Acute administration of morphine decreased the expression of Fos-LI in non-tolerant rats, while the expression of Fos-LI was significantly increased in morphine-tolerant rats. Fos-LI was distributed not only in the whole laminae of the ipsilateral spinal cord but also in the contralateral spinal cord. Acute administration of morphine was ineffective in decreasing the expression of Fos-LI in morphine-tolerant rats. Morphine tolerance increased the expression of formalin-induced NADPH-d positive neurons in the superficial laminae of spinal dorsal horn. A few formalin-induced Fos/NADPH-d double-labeled neurons were detected in the superficial laminae of spinal dorsal horn of non-tolerant rats. In morphine-tolerant rats, on the other hand, formalin-induced Fos/NADPH-d double-labeled neurons were increased and distributed in the whole laminae of the ipsilateral spinal cord and the contralateral superficial spinal cord. It is suggested that NO is involved in the increase of formalin-induced Fos-LI in the spinal cord of morphine-tolerant rats and may play an important role in the development of morphine tolerance.

Conversion of a mitochondrial gene for mammalian cytochrome c oxidase subunit II into its universal codon equivalent and expression in vivo and in vitro

To begin to assess the independent structural and functional characteristics of the mitochondrially encoded subunits of mammalian cytochrome c oxidase, we have converted the cloned mitochondrial gene for rat subunit II (coxII) into its universal codon equivalent (ucoxII) by oligonucleotide-directed, site-specific mutagenesis. This involved synthesizing 12 oligodeoxynucleotides to achieve the 13 ATA to ATG and the 5 TGA to TGG changes needed. To express ucoxII in Escherichia coli, we used a number of different expression vectors in which the promoters and ribosome-binding sequences of the messenger RNA were varied. While ucoxII alone was expressed at a low level, a striking increase in the level of expression resulted when the ucoxII gene was fused to other E. coli genes. The COXII peptide was identified by proteolytic digestion, partial sequencing, and reaction with specific antisera. A cro-beta-galactosidase-COXII fusion protein has been purified, characterized, and used to produce polyclonal antibodies to the COXII peptide. The ucoxII gene was also expressed in a cell-free translation system and in Xenopus oocytes, yielding a nondenatured, membrane-associated peptide with the same apparent molecular weight as authentic subunit II. In oocytes and in a reticulocyte lysate in vitro system supplemented with microsomal membranes, the protein is glycosylated and coisolates with the washed membrane fraction. In both cases, the COXII peptide is soluble under mild conditions in a nonionic detergent and is precipitable by antibodies to subunit II. The production of subunit II in the in vitro translation system is stimulated as strongly by addition of soybean phospholipid vesicles as by microsomal membranes, providing further evidence of membrane insertion and stabilization.(ABSTRACT TRUNCATED AT 250 WORDS)

Specific sequences downstream from -6 are not essential for proper and efficient in vitro utilization of the Escherichia coli lactose promoter

A series of deletion mutants of the wild-type Escherichia coli lactose promoter, with endpoints at +25, +19, +14, +1 and -6 (relative to the start of transcription at +1), was constructed and the deleted DNA replaced with non-lac DNA. These mutants were used to show that no specific DNA sequences downstream from -6 are required for efficient promoter utilization in vitro. In all cases transcription is dependent on the presence of the catabolite activator protein (CAP) and cAMP, and begins at +1 at a level indistinguishable from that at the wild-type promoter. A set of lac DNA fragments deleted to -6 was constructed, having an A, C, G or T residue at +1 and heterologous DNA downstream. These synthetic promoters allow systematic testing of the effect of the initiating nucleotide on the transcription process. Again, transcription occurs mainly from +1, at a level similar to the normal wild-type level. No substantial differences between these promoters are observed in the rates of formation of stable complexes, in the degree of complex formation, in the rate at which polymerase "escapes" from the complex or in abortive transcription products. Equivalent results are seen with a related set of constructs based on the CAP-insensitive lac UV5 promoter. Thus, lac promoter sequences including consensus hexamers at -10 and -35, plus the spacer region between them, provide specificity and efficiency both in initiation of transcription by RNA polymerase and in CAP-polymerase interactions. A question as to whether there is a third RNA polymerase binding site at lac, in addition to the known overlapping P1 and P2 regions, was not unambiguously answered. However, if a "P3" site does exist, it must lie between P1 and P2. Alternatively, the variety of polymerase interactions at wild-type lac may reflect different structural states of the enzyme. The results presented here indicate that DNA downstream from -6 plays little part in determining the conformation of the enzyme at the lactose promoter.